Numerous association studies have been performed to evaluate the relationship between the angiotensinogen gene and the essential hypertension, but their results are conflicting. The conflicting results may be explained by methodological reasons, particularly genetic differences in the population sam
ples, phenotypic differences in the hypertensive populations analyzed, lack of appropriate control for other hypertension risk factors in some studies, or limited statistical power among many studies. Furthermore, hypertension is a public health issue of great relevance in Baleric Islands (Spain). For these reasons we performed an association study about the relationship between the M235T, T174M and G-6A diallelic polymorphisms of the angiotensinogen gene and hypertension in a population from Majorca (Balearic Islands), in which a considerable homogeneity with respect to ethnicity and environmental factors could be documented. This population was composed of 109 patients and 107 controls. Alleles of the angiotensinogen gene were determined by PCR and restriction site polymorphism analysis. The different genotypes were tested for association with dependent variables by univariate and multivariate logistic regression analysis. In the univariate analysis we found no evidence of association between the angiotensinogen gene genotypes and hypertension. This lack of association was independent of obesity, familial history of hypertension and diabetes for the genotypes of the polymorphisms M235T and G-6A; however, in the multivariate analysis the T174T174 genotype showed an almost significant positive association with hypertension [OR = 2.76 (95% confidence interval: 1.00-7.65, p = 0.05)]. The T174T174 genotype also showed a significant negative association with obesity [OR = 0.41 (95% confidence interval: 0.18-0.90, p = 0.03)] that remained after adjustment by sex, hypertension and diabetes [OR = 0.26 (95% confidence interval: 0.10-0.65, p = 0.004)]. Our results: a) are in contrast with the results from most previous studies that found a relationship of the T174M polymorphism with hypertension, as in those studies the M174 allele was responsible for the association; b) emphasize the need for rigorous control for obsesity in the studies of association between the angiotensinogen gene and hypertension; c) underscore the importance and the utility of using concrete populations to carry out studies on the genetic dissection of hypertension.
Marco RA, etal., Hear Res. 1996 Aug;97(1-2):95-101.
The distribution of calcitonin gene-related peptide immunoreactivity (CGRPi) within efferent vestibular neurons in the chinchilla was investigated using fluorescent retrograde labeling combined with immunohistochemistry. Efferent vestibular neurons were found bilaterally in clusters: dorsolateral (g
roup E1) and medial (group E2) to the genu of CN VII, as well as ventromedial to the descending CN VII fibers in the parvicellular reticular formation (PCR). The percentage of retrogradely labeled cells containing CGRPi was 77.1 +/- 5.7 for group E1 neurons, 90.3 +/- 3.8 in the E2 region. Among the PCR efferents more then half of the neurons (61.4 +/- 19.9%) expressed CGRP peptide or message. The wide distribution of CGRP among vestibular efferent neurons suggests that CGRP plays an important role in vestibular efferent function. In addition, the differential distribution among the groups of vestibular efferent neurons suggests that efferent modulation of vestibular function is different between the E cell group efferent neurons and the PCR efferent neurons.
Marco J, etal., Peptides. 2008 May;29(5):852-8. Epub 2007 Sep 4.
In the perfused rat pancreas, infusion of urotensin-II (UII), a somatostatin-like peptide, inhibits glucose-induced insulin secretion. We have resorted to specific antagonists of the UII receptor (UT), palosuran and urantide, to investigate whether endogenous UII also behaves as an inhibitor of beta
-cell secretion. The insulinostatic effect of UII was counteracted by palosuran and by urantide but not by a somatostatin-receptor antagonist (cyclo-somatostatin). Furthermore, the insulinostatic effect of somatostatin was not reversed by palosuran. These results suggest that UII and somatostatin blocked beta-cell secretion via distinct receptors. Finally, in the absence of exogenous UII, both palosuran and urantide potentiated glucose-induced insulin release, thus supporting the concept that endogenous UII is an insulinostatic peptide. By virtue of their insulinotropic effect, UT antagonists may be considered potential drugs for treating the impaired insulin secretion characteristic of type 2 diabetic patients.
Marco A, etal., Psychoneuroendocrinology. 2013 Dec;38(12):2844-53. doi: 10.1016/j.psyneuen.2013.07.011. Epub 2013 Aug 16.
Impaired response of the brain to the leptin signal leads to a persisting dysregulation of food intake and energy balance. High plasma leptin or insulin should activate proopiomelanocortin (POMC), the precursor of the anorexigenic neuropeptide α-melanocyte-stimulating hormone (α-MSH) in
the hypothalamic arcuate nucleus (ARC). Nevertheless, in obesity, this signal transduction pathway might be impaired. In this study we investigated whether chronic high fat (HF) diet consumption from post-weaning to adulthood increases CpG methylation of the Pomc promoter. The hypothesis that this would disrupt the essential binding of the transcription factor Sp1 to the Pomc promoter was tested. Male rats were raised from postnatal day 21 till 90 on either HF or standard diet. As a result HF fed rats were significantly heavier, with high leptin and insulin levels in their plasma but almost no changes in ARC mRNA expression levels of Pomc. The Pomc promoter area in the HF-treated rats was found to be hypermethylated. Furthermore, there was a direct correlation in individual rats between CpG methylation at specific sites that affect Sp1 binding and plasma leptin levels and/or body weight. Although, as expected the HF diet resulted in up-regulation of Sp1, the binding of Sp1 to the hypermethylated Pomc promoter was significantly reduced. Therefore, we suggest that hypermethylation on the promoter region of the Pomc gene can emerge at post-lactation periods and interfere with transcription factor binding, thus blocking the effects of high leptin levels, leading to obesity.
Marco S, etal., Dis Model Mech. 2016 Sep 1;9(9):999-1013. doi: 10.1242/dmm.025171. Epub 2016 Aug 4.
Mucopolysaccharidosis type IIIC (MPSIIIC) is a severe lysosomal storage disease caused by deficiency in activity of the transmembrane enzyme heparan-alpha-glucosaminide N-acetyltransferase (HGSNAT) that catalyses the N-acetylation of alpha-glucosamine residues of heparan sulfate. Enzyme deficiency c
auses abnormal substrate accumulation in lysosomes, leading to progressive and severe neurodegeneration, somatic pathology and early death. There is no cure for MPSIIIC, and development of new therapies is challenging because of the unfeasibility of cross-correction. In this study, we generated a new mouse model of MPSIIIC by targeted disruption of the Hgsnat gene. Successful targeting left LacZ expression under control of the Hgsnat promoter, allowing investigation into sites of endogenous expression, which was particularly prominent in the CNS, but was also detectable in peripheral organs. Signs of CNS storage pathology, including glycosaminoglycan accumulation, lysosomal distension, lysosomal dysfunction and neuroinflammation were detected in 2-month-old animals and progressed with age. Glycosaminoglycan accumulation and ultrastructural changes were also observed in most somatic organs, but lysosomal pathology seemed most severe in liver. Furthermore, HGSNAT-deficient mice had altered locomotor and exploratory activity and shortened lifespan. Hence, this animal model recapitulates human MPSIIIC and provides a useful tool for the study of disease physiopathology and the development of new therapeutic approaches.
Marco S, etal., J Neurobiol. 2002 Sep 15;52(4):343-51.
Glial cell line-derived neurotrophic factor (GDNF) family members have been proposed as candidates for the treatment of Parkinson's disease because they protect nigral dopaminergic neurons against various types of insult. However, the efficiency of these factors depends on the availability of their
receptors after damage. We evaluated the changes in the expression of c-Ret, GFRalpha1, and GFRalpha2 in the substantia nigra pars compacta in a rat model of Parkinson's disease by in situ hybridization. Intrastriatal injection of 6-hydroxydopamine (6-OHDA) transiently increased c-Ret and GFRalpha1 mRNA levels in the substantia nigra pars compacta at 1 day postlesion. At later time points, 3 and 6 days, the expression of c-Ret and GFRalpha1 was downregulated. GFRalpha2 expression was differentially regulated, as it decreased only 6 days after 6-OHDA injection. Triple-labeling studies, using in situ hybridization for the GDNF family receptors and immunohistochemistry for neuronal or glial cell markers, showed that changes in the expression of c-Ret, GFRalpha1, and GFRalpha2 in the substantia nigra pars compacta were localized to neurons. In conclusion, our results show that nigral neurons differentially regulate the expression of GDNF family receptors as a transient and compensatory response to 6-OHDA lesion.
Marco EM, etal., Pharmacol Biochem Behav. 2017 Jan;152:68-80. doi: 10.1016/j.pbb.2016.11.005. Epub 2016 Nov 25.
Alcohol use disorder and depression are highly comorbid, and both conditions exhibit important sexual dimorphisms. Here, we aimed to investigate voluntary alcohol consumption after 6weeks of chronic mild stress (CMS) in Wistar rats - employed as an animal model of depression. Male and female rats we
re investigated, and changes in several molecular markers were analysed in frontal cortex (FCx) and hippocampal formation (HF). CMS induced depressive-like responses in the forced swimming test - increased immobility time - in male and female animals, without affecting anhedonia (sucrose preference test) nor motor activity (holeboard); body weight gain and food intake were diminished only among CMS males. Voluntary alcohol consumption was evaluated in a two-bottle choice paradigm (ethanol 20% versus tap water) for 4 consecutive days; females exhibited a higher preference for alcohol compared to male animals. In particular, alcohol consumption was significantly higher among CMS females compared to CMS male animals. Remarkably, similar changes in both male and female animals exposed to CMS were observed regarding the expression levels of NCAM-140KDa (decrease), GFAP and CB1R expression (increase) within the FCx as well as for HF PSD-95 levels (increase). However, contrasting effects in males and females were reported in relation to synaptophysin (SYN) protein levels within the FCx, HF CB1R expression (a decrease among male animals but an increase in females); while the opposite pattern was observed for NCAM-140KDa protein levels in the HF. A decrease in CB2R expression was only observed in the HF of CMS-females. The present study suggests that male and female animals might be differentially affected by CMS regarding later voluntary alcohol consumption. In this initial approach, cortical SYN, and NCAM-140KDa, CB1R and CB2R expression within the HF have arisen as potential candidates to explain such sex differences in behaviour. However, the depression-alcoholism relationship still deserves further investigation.
BACKGROUND: Cyclooxygenase (COX)-2 activity has been said to have a protective effect in asthmatic patients as a result of prostaglandin E(2) production. In order to elucidate the mechanisms involved, we evaluated the impact of selective inhibition of COX-2 with rofecoxib during ovalbumin challenge,
assessing mast cell activity and airway response in a murine model of asthma. MATERIAL AND METHODS: Mice were sensitized to ovalbumin (10 microg injected intraperitoneally) and further challenged with 0.5% intranasal ovalbumin. Half the sensitized animals were treated orally with rofecoxib (15 mg/kg/d during the challenge phase). Lung function was measured by whole body plethysmography before and after exposure to ovalbumin. The severity of airway inflammation was evaluated by means of a scoring system. Finally, the serum level of mouse mast cell protease-1 was determined as an indicator of mucosal mast cell activity. RESULTS: Sensitized mice treated with rofecoxib exhibited 2.4-fold greater airway hyperresponsiveness than did vehicle-treated mice at a methacholine concentration of 100mg/ml. A clear trend toward worsening airway inflammation in the presence of rofecoxib was observed, although the difference between rofecoxib-treated and vehicle-treated animals was not significant. These changes were accompanied by a significant increase in mucosal mast cell activity. CONCLUSIONS: Selective pharmacological inhibition of COX-2 during the challenge phase worsens airway function in the ovalbumin -induced murine model of acute asthma. We suggest that this effect might be at least partially explained by the increase in airway mast cell activity.
Annexin V has phospholipid-binding capacity and plays a potent antithrombotic role. Recently, a C to T transition has been described in the Kozak region of this gene, affecting the nucleotide preceding the initiation ATG codon. We have developed a simple method to detect this genetic change, showing
by analysis of 580 Mediterranean white subjects that the -1C to T transition (-1C>T) is a common polymorphism (allele frequency, 0.121). This polymorphism is in linkage disequilibrium with a new C>G polymorphism located 27 bp downstream in intron 2. We show that -1C/C carriers presented significantly lower plasma levels of annexin V than -1C/T subjects (0.45 +/- 0.20 ng/mL versus 0.73 +/- 0.28 ng/mL, respectively; P =.02). In vitro transcription/translation experiments support that the -1T allele increases translation efficiency. The clinical relevance of the -1C>T change was investigated in consecutive patients with nontraumatic spontaneous intracranial hemorrhage (n = 225), deep venous thrombosis (n = 151), and coronary heart disease (n = 101). Finally, we also studied 166 survivors of an acute myocardial infarction occurring at age of 45 or less. This polymorphism seems to have a minor effect in bleeding disorders, but to play a protective role against early myocardial infarction, reducing by 2-fold the risk of developing the disease (P =.006; odds ratio, 0.51; 95% confidence interval, 0.30-0.85).
Serra-Pages M, etal., Clin Exp Allergy. 2015 Oct;45(10):1590-600. doi: 10.1111/cea.12542.
BACKGROUND: Prostaglandin E2 (PGE2 ) has been proposed to exert antiasthmatic effects in patients, to prevent antigen-induced airway pathology in murine models, and to inhibit mast cells (MC) activity in vitro. OBJECTIVE: To assess in a murine model whether the protective effect of PGE2 may be a con
sequence of its ability to activate the E-prostanoid (EP)2 receptor on airway MC. METHODS: Either BALB/c or C57BL/6 mice were exposed intranasally (i.n.) to house dust mite (HDM) aeroallergens. Both strains were given PGE2 locally (0.3 mg/kg), but only BALB/c mice were administered butaprost (EP2 agonist: 0.3 mg/kg), or AH6809 (EP2 antagonist; 2.5 mg/kg) combined with the MC stabilizer sodium cromoglycate (SCG: 25 mg/kg). Airway hyperresponsiveness (AHR) and inflammation, along with lung MC activity, were evaluated. In addition, butaprost's effect was assessed in MC-mediated passive cutaneous anaphylaxis (PCA) in mice challenged with 2,4-dinitrophenol (DNP). RESULTS: Selective EP2 agonism attenuated aeroallergen-caused AHR and inflammation in HDM-exposed BALB/c mice, and this correlated with a reduced lung MC activity. Accordingly, the blockade of endogenous PGE2 by means of AH6809 worsened airway responsiveness in sensitive BALB/c mice, and such worsening was reversed by SCG. The relevance of MC to PGE2 -EP2 driven protection was further highlighted in MC-dependent PCA, where butaprost fully prevented MC-induced ear swelling. Unlike in BALB/c mice, PGE2 did not protect the airways of HDM-sensitized C57BL/6 animals, a strain in which we showed MC to be irrelevant to aeroallergen-driven AHR and inflammation. CONCLUSIONS & CLINICAL RELEVANCE: The beneficial effect of both exogenous and endogenous PGE2 in aeroallergen-sensitized mice may be attributable to the activation of the EP2 receptor, which in turn acts as a restrainer of airway MC activity. This opens a path towards the identification of therapeutic targets against asthma along the 'EP2 -MC-airway' axis.
Herrerias A, etal., J Inflamm (Lond). 2009 Oct 30;6:30.
ABSTRACT: BACKGROUND: Prostaglandin E2 (PGE2), experimentally administered to asthma patients or assayed in murine models, improves allergen-driven airway inflammation. The mechanisms are unknown, but fluctuations of the endogenous cyclooxygenase (COX)-2/prostaglandin/E prostanoid (EP) receptor path
way activity likely contribute to the clinical outcome. We analyzed the activity of the pathway in mice sensitized to aeroallergens, and then studied its modulation under exogenous PGE2. METHODS: Mice were exposed to house dust mite (HDM) aeroallergens, a model that enable us to mimic the development of allergic asthma in humans, and were then treated with either subcutaneous PGE2 or the selective EP1/3 receptor agonist sulprostone. Simultaneously with airway responsiveness and inflammation, lung COX-2 and EP receptor mRNA expression were assessed. Levels of PGE2, PGI2, PGD2 were also determined in bronchoalveolar lavage fluid. RESULTS: HDM-induced airway hyperreactivity and inflammation were accompanied by increased COX-2 mRNA production. In parallel, airway PGE2 and PGI2, but not PGD2, were upregulated, and the EP2 receptor showed overexpression. Subcutaneous PGE2 attenuated aeroallergen-driven airway eosinophilic inflammation and reduced endogenous PGE2 and PGI2 production. Sulprostone had neither an effect on airway responsiveness or inflammation nor diminished allergen-induced COX-2 and PGE2 overexpression. Finally, lung EP2 receptor levels remained high in mice treated with PGE2, but not in those treated with sulprostone. CONCLUSION: The lung COX-2/PGE2/EP2 receptor pathway is upregulated in HDM-exposed mice, possibly as an effort to attenuate allergen-induced airway inflammation. Exogenous PGE2 downregulates its endogenous counterpart but maintains EP2 overexpression, a phenomenon that might be required for administered PGE2 to exert its protective effect.
Alpha-1 antitrypsin deficiency (AATD) is a hereditary liver disease caused by mutations in the SERPINA1 serine protease inhibitor gene. Most severe patients are homozygous for PiZ alleles (PiZZ; amino acid E324K), which lead to protein aggregates in hepatocytes and reduced circulating levels of AAT.
The liver aggregates typically lead to fibrosis, cirrhosis, and hepatocellular carcinoma, and the reduced circulating AAT levels can lead to emphysema and chronic obstructive pulmonary diseases. In this study, two CRISPR/Cas9 gene editing approaches were used to decrease liver aggregates and increase systemic AAT-M levels in the PiZ transgenic mouse. In the first approach, AAT expression in hepatocytes was reduced more than 98% following the systemic delivery of AAV8-CRISPR targeting exon 2 of hSERPINA1, leading to reduced aggregates in hepatocytes. In the second approach, a second adeno-associated virus, which provided the donor template to correct the Z mutation, was also administered. These treated mice had reduced AAT expression (> 98%) and a low level (5%) of wildtype AAT-M mRNA. Taken together, this study shows that CRISPR gene editing can efficiently reduce liver expression of AAT-Z and restore modest levels of wildtype AAT-M in a mouse model of AATD, raising the possibility of CRISPR gene editing therapeutic for AATD.
Bas E, etal., Acta Otolaryngol. 2009 Apr;129(4):385-9. doi: 10.1080/00016480802566279.
CONCLUSION: The calcineurin inhibitor tacrolimus (TCR) and the pineal gland hormone and antioxidant melatonin (MLT) have been shown to possess otoprotective properties against noise-induced hearing loss (NIHL). In contrast, dexamethasone (DXM) was not effective as an otoprotective agent against NI
HL. Further studies are needed to understand the exact molecular mechanisms involved. OBJECTIVE: Exposure to noise pollution and use of audio devices for long periods of time at high volume is known to cause hearing loss or NIHL. Our goal was to evaluate the effectiveness of various known compounds such as the anti-inflammatory DXM, the antioxidant MLT and the immunosuppressant TCR against NIHL. MATERIALS AND METHODS: Thirty-two Wistar rats were randomly divided into groups that were then exposed to intense white noise at 120 dB SPL for 4 h. The day before and for a period of 14 days, test groups were administered one of the three compounds. The efficacy of the compounds against NIHL was determined after examining the shifts in the levels of distortion product otoacoustic emissions (DPOAEs) and changes in the threshold of auditory brainstem responses (ABRs). Cytocochleograms and determination of gene expression in whole rat cochlea were carried out at day 21. RESULTS: Treatment with DXM had no otoprotective effect, while animals treated with MLT experienced an improvement in their hearing functionality. This effect, which is probably linked to MLT's ability to reduce c-fos and TNF-alpha gene expression thereby preventing outer hair cell (OHC) loss, was even more pronounced in week 3. For its part, TCR provided protection against injury to the cochlea from week 1, eventually leading to a full recovery in hearing. The compound reduced both c-fos and TNF-alpha expression, as well as OHC loss.
BACKGROUND: Andes virus (ANDV) is the sole etiologic agent of hantavirus cardiopulmonary syndrome (HCPS) in Chile, with a fatality rate of about 35%. Individual host factors affecting ANDV infection outcome are poorly understood. In this case-control genetic association analysis, we explored the lin
k between single-nucleotide polymorphisms (SNPs) rs12979860, rs8099917 and rs1800629 and the clinical outcome of ANDV-induced disease. The SNPs rs12979860 and rs8099917 are known to play a role in the differential expression of the interleukin 28B gene (IL28B), whereas SNP rs1800629 is implicated in the expression of tumor necrosis factor alpha gene (TNF-alpha). METHODS: A total of 238 samples from confirmed ANDV-infected patients collected between 2006 and 2014, and categorized according to the severity of the disease, were genotyped for SNPs rs12979860, rs8099917, and rs1800629. RESULTS: Analysis of IL28B SNPs rs12979860 and rs8099917 revealed a link between homozygosity of the minor alleles (TT and GG, respectively), displaying a mild disease progression, whereas heterozygosity or homozygosity for the major alleles (CT/CC and TG/TT, respectively) in both IL28B SNPs is associated with severe disease. No association with the clinical outcome of HCPS was observed for TNF-alpha SNP rs1800629 (TNF -308G>A). CONCLUSIONS: The IL28B SNPs rs12979860 and rs8099917, but not TNF-alpha SNP rs1800629, are associated with the clinical outcome of ANDV-induced disease, suggesting a possible link between IL28B expression and ANDV pathogenesis.
Rodriguez-Ballesteros M, etal., Hum Mutat. 2003 Dec;22(6):451-6.
Inherited hearing impairment affects one in 2,000 newborns. Nonsyndromic prelingual forms are inherited mainly as autosomal recessive traits, for which 16 genes are currently known. Mutations in the genes encoding connexins 26 and 30 account for up to 50% of these cases. However, the individual cont
ribution of the remaining genes to the whole remains undetermined. In addition, for most of the genes there is a need for studies on genotype-phenotype correlations, to identify distinctive clinical features which may direct the molecular diagnosis to specific genes. Here we present a mutation analysis and a genotype-phenotype correlation study on the gene encoding otoferlin (OTOF), responsible for the DFNB9 subtype of prelingual hearing impairment. Four novel mutations were identified: c.2122C>T (p.Arg708Ter), c.4275G>A (p.Trp1425Ter), c.4362+2T>G, and c.5860_5862delATC (p.Ile1954del). A total of 37 subjects with mutations in OTOF were studied clinically. They were phenotypically homogeneous, having profound hearing impairment with very early onset, as shown by pure-tone audiometry and auditory brainstem responses. Magnetic resonance imaging and computed tomography did not reveal any inner ear malformation. Unexpectedly, transient evoked otoacoustic emissions (TEOAEs) were present, either bilaterally or unilaterally in 11 subjects. Altogether, clinical data of these subjects met the diagnostic criteria of auditory neuropathy. A total of 10 subjects had been successfully provided with cochlear implants. The results of our study indicate that genetic diagnosis of subjects with auditory neuropathy and profound hearing impairment should be directed to the otoferlin gene. Our data are of concern to universal screening programs which use TEOAEs as the first detection test for hearing impairment in newborns, since this technique may overlook a nonnegligible proportion of cases.
We present our experience with the diagnosis of 26 patients (19 families) with congenital disorders of glycosylation classified as type Ia due to PMM deficiency. In all but one of these CDG Ia families the patients are compound heterozygous for mutations in PMM2. Eighteen different mutations were de
tected. In contrast to other series in which R141H represents 43-50% of the alleles, only 9/36 (25%) alleles have this mutation. Two mutations (R123Q and T237M) have been found on three disease chromosomes, four (V44A, Y64C, P113L and F207S) on two disease chromosomes and 12 mutations (D65Y, Y76C, IVS3+2C>T, E93A, R123X, V129M, I153T, F157S, E197A, N216I, T226S, C241S) only on one disease chromosome. V44A and D65Y probably originated in the Iberian peninsula, as they have only been reported in Portuguese and Latin-American patients; Y64C, Y76C, R123X and F207S have not been detected in other patients. R123X is the only stop codon mutation so far described in PMM2. The common European F119L mutation has not been found in our patients, although it is very frequent in other populations (43% allele frequency in Danish patients). Probably because of this genetic heterogeneity, Spanish patients show very diverse phenotypes that are, in general, milder than in other series. This points to the necessity of widening the criteria for CDG in the routine screening for inborn metabolic diseases.
Brancati F, etal., Am J Hum Genet. 2007 Jul;81(1):104-13. doi: 10.1086/519026. Epub 2007 May 18.
Joubert syndrome-related disorders (JSRDs) are a group of clinically and genetically heterogeneous conditions that share a midbrain-hindbrain malformation, the molar tooth sign (MTS) visible on brain imaging, with variable neurological, ocular, and renal manifestations. Mutations in the CEP290 gene
were recently identified in families with the MTS-related neurological features, many of which showed oculo-renal involvement typical of Senior-Loken syndrome (JSRD-SLS phenotype). Here, we performed comprehensive CEP290-mutation analysis on two nonoverlapping cohorts of JSRD-affected patients with a proven MTS. We identified mutations in 19 of 44 patients with JSRD-SLS. The second cohort consisted of 84 patients representing the spectrum of other JSRD subtypes, with mutations identified in only two patients. The data suggest that CEP290 mutations are frequently encountered and are largely specific to the JSRD-SLS subtype. One patient with mutation displayed complete situs inversus, confirming the clinical and genetic overlap between JSRDs and other ciliopathies.
Jansen S, etal., Am J Hum Genet. 2017 Apr 6;100(4):650-658. doi: 10.1016/j.ajhg.2017.02.005. Epub 2017 Mar 23.
Intellectual disability (ID) is a highly heterogeneous disorder involving at least 600 genes, yet a genetic diagnosis remains elusive in ∼35%-40% of individuals with moderate to severe ID. Recent meta-analyses statistically analyzing de novo mutations in >7,000 individuals with neurodevelopmental di
sorders highlighted mutations in PPM1D as a possible cause of ID. PPM1D is a type 2C phosphatase that functions as a negative regulator of cellular stress-response pathways by mediating a feedback loop of p38-p53 signaling, thereby contributing to growth inhibition and suppression of stress-induced apoptosis. We identified 14 individuals with mild to severe ID and/or developmental delay and de novo truncating PPM1D mutations. Additionally, deep phenotyping revealed overlapping behavioral problems (ASD, ADHD, and anxiety disorders), hypotonia, broad-based gait, facial dysmorphisms, and periods of fever and vomiting. PPM1D is expressed during fetal brain development and in the adult brain. All mutations were located in the last or penultimate exon, suggesting escape from nonsense-mediated mRNA decay. Both PPM1D expression analysis and cDNA sequencing in EBV LCLs of individuals support the presence of a stable truncated transcript, consistent with this hypothesis. Exposure of cells derived from individuals with PPM1D truncating mutations to ionizing radiation resulted in normal p53 activation, suggesting that p53 signaling is unaffected. However, a cell-growth disadvantage was observed, suggesting a possible effect on the stress-response pathway. Thus, we show that de novo truncating PPM1D mutations in the last and penultimate exons cause syndromic ID, which provides additional insight into the role of cell-cycle checkpoint genes in neurodevelopmental disorders.
The discoidin domain receptor 1 (DDR1) is a member of the receptor tyrosine kinase family that signals in response to collagen and that has been implicated in cancer progression. In the present study, we investigated the expression and role of DDR1 in human melanoma progression. Immunohistochemical
staining of human melanoma specimens (n = 52) shows high DDR1 expression in melanoma lesions that correlates with poor prognosis. DDR1 expression was associated with the clinical characteristics of Clark level and ulceration and with BRAF mutations. Downregulation of DDR1 by small interfering RNA (siRNA) in vitro inhibited melanoma cells malignant properties, migration, invasion, and survival in several human melanoma cell lines. A DDR tyrosine kinase inhibitor (DDR1-IN-1) significantly inhibited melanoma cell proliferation in vitro, and ex vivo and in tumor xenografts, underlining the promising potential of DDR1 inhibition in melanoma.
BACKGROUND: Hepatic reperfusion injury may cause acute inflammatory damage, producing significant organ dysfunction, and is an important problem in liver transplantation. This experiment aimed to study early changes of hepatic function after donor liver denervation and Kupffer cell deplet
ion in rat-to-rat liver transplantation and to evaluate the effect of pre-treatment on liver reperfusion injury. METHODS: Donor rats were divided into four groups: control group; group G was pre-treated with gadolinium chloride (G), an inhibitor of Kupffer cells; group H with hexamethonium (H), a sympathetic ganglionic blocking agent; and group HG, with combined H and G pre-treatment. Under the same conditions, serum alanine aminotransferase (ALT), arterial ketone body ratio (AKBR), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and superoxide dismutase (SOD) of recipient rats were assessed at 4, 8, 16 and 24 hours after liver transplantation. Histological studies of the grafts were compared. RESULTS: HG pre-treatment significantly decreased ALT, TNF-alpha, and IL-6 levels, increased AKBR and SOD levels, and demonstrated less pathological damage at 8, 16 and 24 hours compared with the control group. Similar trends were also found in the other groups (G and H). However, the differences among them were not significant at 4 post-operative hours. CONCLUSIONS: Donor denervation and Kupffer cell depletion had preventive effect on liver reperfusion injury. HG pre-treatment is a feasible and reproducible method to protect grafts from reperfusion injury.
Notch signaling is an established developmental pathway for brain morphogenesis. Given that Delta-like 1 (DLL1) is a ligand for the Notch receptor and that a few individuals with developmental delay, intellectual disability, and brain malformations have microdeletions encompassing DLL1, we hypothesi
zed that insufficiency of DLL1 causes a human neurodevelopmental disorder. We performed exome sequencing in individuals with neurodevelopmental disorders. The cohort was identified using known Matchmaker Exchange nodes such as GeneMatcher. This method identified 15 individuals from 12 unrelated families with heterozygous pathogenic DLL1 variants (nonsense, missense, splice site, and one whole gene deletion). The most common features in our cohort were intellectual disability, autism spectrum disorder, seizures, variable brain malformations, muscular hypotonia, and scoliosis. We did not identify an obvious genotype-phenotype correlation. Analysis of one splice site variant showed an in-frame insertion of 12 bp. In conclusion, heterozygous DLL1 pathogenic variants cause a variable neurodevelopmental phenotype and multi-systemic features. The clinical and molecular data support haploinsufficiency as a mechanism for the pathogenesis of this DLL1-related disorder and affirm the importance of DLL1 in human brain development.
Neilson DE, etal., Am J Hum Genet. 2009 Jan;84(1):44-51. doi: 10.1016/j.ajhg.2008.12.009.
Acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy that can occur in otherwise healthy children after common viral infections such as influenza and parainfluenza. Most ANE is sporadic and nonrecurrent (isolated ANE). However, we identified a 7 Mb interval containing a sus
ceptibility locus (ANE1) in a family segregating recurrent ANE as an incompletely penetrant, autosomal-dominant trait. We now report that all affected individuals and obligate carriers in this family are heterozygous for a missense mutation (c.1880C-->T, p.Thr585Met) in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2). To determine whether this mutation is the susceptibility allele, we screened controls and other patients with ANE who are unrelated to the index family. Patients from 9 of 15 additional kindreds with familial or recurrent ANE had the identical mutation. It arose de novo in two families and independently in several other families. Two other patients with familial ANE had different RANBP2 missense mutations that altered conserved residues. None of the three RANBP2 missense mutations were found in 19 patients with isolated ANE or in unaffected controls. We conclude that missense mutations in RANBP2 are susceptibility alleles for familial and recurrent cases of ANE.
OBJECTIVE: Ghrelin is a 28 amino acid residue peptide identified in both human and rat stomach and which acts as an endogenous ligand for the GH secretagogue receptor (GHS-R) and stimulates GH release. GHS-Rs are expressed in a number of tissues, including the pancreas, and ghrelin-like immunoreacti
vity is present in peripheral plasma, where its levels increase during fasting and decrease after food intake. The relationship between nutritional status and circulating ghrelin concentrations prompted us to investigate the effect of this peptide on pancreatic hormone secretion. METHODS: The study was performed in the isolated rat pancreas perfused in situ. Insulin, glucagon and somatostatin were measured by radioimmunoassay. RESULTS: Addition of 10 nM ghrelin to the perfusate significantly reduced the insulin response to the secretagogues glucose, arginine and carbachol, which act on the B-cell via different mechanisms, as well as the somatostatin response to arginine. Ghrelin was without effect on the glucagon output induced by this amino acid. At a lower concentration (2 nM) ghrelin was also found to inhibit glucose-induced insulin release. CONCLUSION: These findings support the proposal that the inhibitory effect of ghrelin on insulin release constitutes a tonic regulation of the B-cell, contributing to restrain its secretory activity in the state of food deprivation. On the other hand, the inhibition of pancreatic somatostatin release by ghrelin suggests a blocking effect of this hormone on the widely distributed D-cell population.
PURPOSE: To study the lipid hydroperoxide activity in vasoproliferative and fibroproliferative retinal disorders. METHODS: Vitreous body samples from patients undergoing vitrectomy because of proliferative vitreoretinopathy (PVR; n = 12) or proliferative diabetic retinopathy (PDR; n = 15), and rhegm
atogenous retinal detachment/macular hole/epiretinal membranes as the comparison group (CG; n = 14), were analysed for protein content and basal and induced lipid peroxidation (LPO), as determined by the thiobarbituric acid reactive substances (TBARS) test and LPO 586 commercial kit. The antioxidant activity for superoxide dismutase (SOD) and catalase (CAT) was also assayed. RESULTS: Malondialdehyde (MDA)-like metabolites and 4-hydroxynonenal (4-HNE) mean values were first measured to assess basal LPO, and found to be significantly higher in the PVR and PDR cases than in the CG (p < or = 0.0001). LPO induced by nicotine adenine dinucleotide phosphate iron (NADPH-Fe) was then assayed and the data showed that MDA mean values were 5-fold greater for the PVR and PDR eyes than in the case of basal LPO (p < or = 0.0001). SOD activity was significantly smaller in the PVR (p = 0.0010) and PDR (p < or = 0.0001) groups than in the CG. CAT levels displayed significantly lower values in the PVR and PDR cases than in the CG (p < or = 0.0001). No significant differences in free radical (FR) formation and antioxidant status between PVR and PDR patients were observed. CONCLUSIONS: Fibrovascular proliferative vitreoretinopathies correlate with increased FR formation and decreased antioxidant activity in the human vitreous body.
Leo D, etal., Genes Brain Behav. 2009 Apr;8(3):356-68. Epub 2009 Feb 19.
Methylphenidate (MPH) administration to adolescent rodents produces persistent region-specific changes in brain reward circuits and alterations of reward-based behavior. We show that these modifications include a marked increment of serotonin (5-hydroxy-tryptamine) receptor type 7 (Htr7) expression
and synaptic contacts, mainly in the nucleus accumbens, and a reduction of basal behavioral impulsivity. We show that neural and behavioral consequences are functionally related: administration of a selective Htr7 antagonist fully counteracts the MPH-reduced impulsive behavior and enhances impulsivity when administered alone in naive rats. Agonist-induced activation of endogenous Htr7 significantly increases neurite length in striatal neuron primary cultures, thus suggesting plastic remodeling of neuronal morphology. The mixed Htr (1a/7) agonist, 8-OH-DPAT, reduces impulsive behavior in adolescent rats and in naive adults, whose impulsivity is enhanced by the Htr7 antagonist. In summary, behavioral pharmacology experiments show that Htr7 mediates self-control behavior, and brain primary cultures experiments indicate that this receptor may be involved in the underlying neural plasticity, through changes in neuronal cytoarchitecture.
The diagnosis of von Willebrand disease (VWD) remains difficult in a significant proportion of patients. A Spanish multicentre study investigated a cohort of 556 patients from 330 families who were analysed centrally. VWD was confirmed in 480. Next generation sequencing (NGS) of the whole coding V
WF was carried out in all recruited patients, compared with the phenotype, and a final diagnosis established. A total of 238 different VWF mutations were found, 154 were not included in the Leiden Open Variation Database (LOVD). Of the patients, 463 were found to have VWF mutation/s. A good phenotypic/genotypic association was estimated in 96.5% of the patients. One hundred seventy-four patients had two or more mutations. Occasionally a predominant phenotype masked the presence of a second abnormality. One hundred sixteen patients presented with mutations that had previously been associated with increased von Willebrand factor (VWF) clearance. RIPA unavailability, central phenotypic results disagreement and difficult distinction between severe type 1 and type 3 VWD prevented a clear diagnosis in 70 patients. The NGS study facilitated an appropriate classification in 63 of them. The remaining seven patients presented with a VWF novel mutation pending further investigation. In five patients with a type 3 and two with a type 2A or 2B phenotype with no mutation, an acquired von Willebrand syndrome (AVWS) was suspected/confirmed. These data seem to support NGS as a first line efficient and faster paradigm in VWD diagnosis.
Connaughton DM, etal., Am J Hum Genet. 2020 Oct 1;107(4):727-742. doi: 10.1016/j.ajhg.2020.08.013. Epub 2020 Sep 4.
Congenital anomalies of the kidney and urinary tract (CAKUT) constitute one of the most frequent birth defects and represent the most common cause of chronic kidney disease in the first three decades of life. Despite the discovery of dozens of monogenic causes of CAKUT, most pathogenic pathways rema
in elusive. We performed whole-exome sequencing (WES) in 551 individuals with CAKUT and identified a heterozygous de novo stop-gain variant in ZMYM2 in two different families with CAKUT. Through collaboration, we identified in total 14 different heterozygous loss-of-function mutations in ZMYM2 in 15 unrelated families. Most mutations occurred de novo, indicating possible interference with reproductive function. Human disease features are replicated in X. tropicalis larvae with morpholino knockdowns, in which expression of truncated ZMYM2 proteins, based on individual mutations, failed to rescue renal and craniofacial defects. Moreover, heterozygous Zmym2-deficient mice recapitulated features of CAKUT with high penetrance. The ZMYM2 protein is a component of a transcriptional corepressor complex recently linked to the silencing of developmentally regulated endogenous retrovirus elements. Using protein-protein interaction assays, we show that ZMYM2 interacts with additional epigenetic silencing complexes, as well as confirming that it binds to FOXP1, a transcription factor that has also been linked to CAKUT. In summary, our findings establish that loss-of-function mutations of ZMYM2, and potentially that of other proteins in its interactome, as causes of human CAKUT, offering new routes for studying the pathogenesis of the disorder.
Spinelli E, etal., Ann Neurol. 2021 Aug;90(2):274-284. doi: 10.1002/ana.26147. Epub 2021 Jul 13.
OBJECTIVE: The MAST family of microtubule-associated serine-threonine kinases (STKs) have distinct expression patterns in the developing and mature human and mouse brain. To date, only MAST1 has been conclusively associated with neurological disease, with de novo variants in individuals w
ith a neurodevelopmental disorder, including a mega corpus callosum. METHODS: Using exome sequencing, we identify MAST3 missense variants in individuals with epilepsy. We also assess the effect of these variants on the ability of MAST3 to phosphorylate the target gene product ARPP-16 in HEK293T cells. RESULTS: We identify de novo missense variants in the STK domain in 11 individuals, including 2 recurrent variants p.G510S (n = 5) and p.G515S (n = 3). All 11 individuals had developmental and epileptic encephalopathy, with 8 having normal development prior to seizure onset at <2 years of age. All patients developed multiple seizure types, 9 of 11 patients had seizures triggered by fever and 9 of 11 patients had drug-resistant seizures. In vitro analysis of HEK293T cells transfected with MAST3 cDNA carrying a subset of these patient-specific missense variants demonstrated variable but generally lower expression, with concomitant increased phosphorylation of the MAST3 target, ARPP-16, compared to wild-type. These findings suggest the patient-specific variants may confer MAST3 gain-of-function. Moreover, single-nuclei RNA sequencing and immunohistochemistry shows that MAST3 expression is restricted to excitatory neurons in the cortex late in prenatal development and postnatally. INTERPRETATION: In summary, we describe MAST3 as a novel epilepsy-associated gene with a potential gain-of-function pathogenic mechanism that may be primarily restricted to excitatory neurons in the cortex. ANN NEUROL 2021;90:274-284.
Granadillo JL, etal., J Med Genet. 2020 Oct;57(10):717-724. doi: 10.1136/jmedgenet-2019-106470. Epub 2020 Mar 9.
BACKGROUND: Rare variants in hundreds of genes have been implicated in developmental delay (DD), intellectual disability (ID) and neurobehavioural phenotypes. TNRC6B encodes a protein important for RNA silencing. Heterozygous truncating variants have been reported in three patients from l
arge cohorts with autism, but no full phenotypic characterisation was described. METHODS: Clinical and molecular characterisation was performed on 17 patients with TNRC6B variants. Clinical data were obtained by retrospective chart review, parent interviews, direct patient interaction with providers and formal neuropsychological evaluation. RESULTS: Clinical findings included DD/ID (17/17) (speech delay in 94% (16/17), fine motor delay in 82% (14/17) and gross motor delay in 71% (12/17) of subjects), autism or autistic traits (13/17), attention deficit and hyperactivity disorder (ADHD) (11/17), other behavioural problems (7/17) and musculoskeletal findings (12/17). Other congenital malformations or clinical findings were occasionally documented. The majority of patients exhibited some dysmorphic features but no recognisable gestalt was identified. 17 heterozygous TNRC6B variants were identified in 12 male and five female unrelated subjects by exome sequencing (14), a targeted panel (2) and a chromosomal microarray (1). The variants were nonsense (7), frameshift (5), splice site (2), intragenic deletions (2) and missense (1). CONCLUSIONS: Variants in TNRC6B cause a novel genetic disorder characterised by recurrent neurocognitive and behavioural phenotypes featuring DD/ID, autism, ADHD and other behavioural abnormalities. Our data highly suggest that haploinsufficiency is the most likely pathogenic mechanism. TNRC6B should be added to the growing list of genes of the RNA-induced silencing complex associated with ID/DD, autism and ADHD.
BACKGROUND: The aim of this study was to evaluate, the existence of a signature of differentially expressed microRNAs (miRNAs) during osteogenic differentiation of bone marrow MSCs from OA and healthy donors and to describe their possible implication in joint regeneration through modulation of mole
cular mechanisms involved in homeostatic control in OA pathophysiology. METHODS: Following phenotypic assessment of BM-MSCs obtained from OA diagnosed patients (n = 10) and non-OA (n = 10), total small RNA was isolated after osteogenic induction for 1, 10 and 21 days, miRNA profiles were generated using a commercial expression array of 754 well-characterized miRNAs. MiRNAs, with consistent differential expression were selected for further validation by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis. RESULTS: A total of 246 miRNAs were differentially expressed (fold change >/= +/- 2, P =0.05) between OA and non-OA BM-MSC samples; these miRNAs showed variable interactions depending on the cell and differentiation status. Two miRNAs, hsa-miR-210 and hsa-miR-335-5p out of 21 used for validation showed a significant downregulated expression during induced osteogenesis. In particular hsa-miR-335-5p, a critical regulator in bone homeostasis, was further studied. hsa-miR-335-5p downregulation in OA-MSCs, as well as their host coding gene, MEST, were also assessed. CONCLUSIONS: To our knowledge, this study represents the most comprehensive assessment to date of miRNA expression profiling in BM-MSCs from OA patients and their role during osteogenic differentiation. We describe the existence of a correlation between miR-335-5p expression and OA indicating the putative role of this miRNA in OA features. These findings, may contribute to our understanding of the molecular mechanisms involved in MSCs mediated homeostatic control in OA pathophysiology that could be applicable in future therapeutic approaches.
Reis GS, etal., J Pediatr (Rio J). 2014 Jan-Feb;90(1):58-64. doi: 10.1016/j.jped.2013.06.004. Epub 2013 Oct 13.
OBJECTIVE: To determine the frequency of different phenotypes for congenital anomalies of the kidney and urinary tract (CAKUT) in a Brazilian sample, and to evaluate the association between the CAKUT phenotypes and the BMP4 gene. METHODS: In this study, 457 Brazilian individuals
were analyzed in an attempt to establish the association between the BMP4 gene and the CAKUT diagnosis. A case-control sample was genotyped for three BMP4 gene polymorphisms. RESULTS: Association data was established with CAKUT sample as a whole and with the three most important CAKUT phenotypes: multicystic dysplastic kidney disease (MDK), ureteropelvic junction obstruction (UPJO) and vesicoureteral reflux (VUR). When the sample was segregated in these three phenotypes, associations between the BMP4 gene were observed with UPJO and with MDK. Conversely, VUR was not associated to the polymorphisms of the BMP4 gene. CONCLUSIONS: The present data suggest that Brazilian individuals with polymorphisms of the BMP4 gene have a higher risk to develop CAKUT, especially the malformations related to nephrogenesis and initial branching such as MDK and UPJO. Conversely, VUR appeared not to be related to BMP4 gene.
Upon activation, neutrophils release DNA fibers decorated with antimicrobial proteins, forming neutrophil extracellular traps (NETs). Although NETs are bactericidal and contribute to innate host defense, excessive NET formation has been linked to the pathogenesis of autoinflammatory diseases. Howeve
r, the mechanisms regulating NET formation, particularly during chronic inflammation, are poorly understood. Here we show that the G protein-coupled receptor (GPCR) CXCR2 mediates NET formation. Downstream analyses showed that CXCR2-mediated NET formation was independent of NADPH oxidase and involved Src family kinases. We show the pathophysiological relevance of this mechanism in cystic fibrosis lung disease, characterized by chronic neutrophilic inflammation. We found abundant NETs in airway fluids of individuals with cystic fibrosis and mouse cystic fibrosis lung disease, and NET amounts correlated with impaired obstructive lung function. Pulmonary blockade of CXCR2 by intra-airway delivery of small-molecule antagonists inhibited NET formation and improved lung function in vivo without affecting neutrophil recruitment, proteolytic activity or antibacterial host defense. These studies establish CXCR2 as a receptor mediating NADPH oxidase-independent NET formation and provide evidence that this GPCR pathway is operative and druggable in cystic fibrosis lung disease.
BACKGROUND: Inflammatory lung diseases are a major morbidity factor in children. Therefore, novel strategies for early detection of inflammatory lung diseases are of high interest. Bacterial lipopolysaccharide (LPS) is recognized via Toll-like receptors and CD14. CD14 exists as a soluble (sCD14) and
membrane-associated (mCD14) protein, present on the surface of leukocytes. Previous studies suggest sCD14 as potential marker for inflammatory diseases, but their potential role in pediatric lung diseases remained elusive. Therefore, we examined the expression, regulation and significance of sCD14 and mCD14 in pediatric lung diseases. METHODS: sCD14 levels were quantified in serum and bronchoalveolar lavage fluid (BALF) of children with infective (pneumonia, cystic fibrosis, CF) and non-infective (asthma) inflammatory lung diseases and healthy control subjects by ELISA. Membrane CD14 expression levels on monocytes in peripheral blood and on alveolar macrophages in BALF were quantified by flow cytometry. In vitro studies were performed to investigate which factors regulate sCD14 release and mCD14 expression. RESULTS: sCD14 serum levels were specifically increased in serum of children with pneumonia compared to CF, asthma and control subjects. In vitro, CpG induced the release of sCD14 levels in a protease-independent manner, whereas LPS-mediated mCD14 shedding was prevented by serine protease inhibition. CONCLUSIONS: This study demonstrates for the first time the expression, regulation and clinical significance of soluble and membrane CD14 receptors in pediatric inflammatory lung diseases and suggests sCD14 as potential marker for pneumonia in children.
The involvement of the cholinergic system in learning and memory together with the cognitive enhancing properties of 5-HT6 receptor antagonists led us to study the relationship between 5-HT6 receptors and cholinergic neurotransmission. A selective cholinergic lesion, induced by injection of the immu
notoxin 192-IgG-Saporin into the nucleus basalis magnocellularis, failed to alter the density of 5-HT6 receptor mRNA or protein expression in the deafferentated frontal cortex, suggesting that 5-HT6 receptors are not located on cholinergic neurons. The 5-HT6 receptor antagonist SB-357134 (0.001-1 microM) induced a concentration-dependant K+-evoked [3H]acetylcholine (ACh) release in vitro in rat cortical and striatal slices, which was blocked by tetrodotoxin. SB-357134, up to 1 microM, stimulated glutamate release in cortical and striatal slices. In the cortex, riluzole (1 microM) blocked the SB-357134-induced K+-stimulated [3H]ACh release, and simultaneous administration of MK-801 (1 microM) and SB-357134 (0.05 microM) elicited an increase in K+-evoked ACh release. In the striatum, SB-357134, 1 microM, decreased dopamine release, and the increase in K+-evoked [3H]ACh release induced by 5-HT6 receptor blockade was reversed by the D1 receptor antagonist, SCH23390 (1 microM). In both the frontal cortex and striatum, bicuculline, 1 microM, showed no effect on SB-357134-evoked [3H]ACh. These results are discussed in terms of neurochemical mechanisms involved in 5-HT6 receptor functions.
Marcos A, etal., Neuropharmacology. 2022 Mar 15;206:108937. doi: 10.1016/j.neuropharm.2021.108937. Epub 2021 Dec 26.
Although the pharmacological and behavioural interactions between cocaine and alcohol are well established, less is known about how polyconsumption of these drugs affects the neurotransmitter systems involved in their psychoactive effects and in particular, in the process of addiction. Here, rats of
both sexes at two stages of development were studied under a chronic regime of intravenous cocaine and/or alcohol administration. Brain samples from the medial prefrontal cortex, nucleus accumbens, hippocampus and amygdala were extracted to analyse the mRNA expression of genes encoding subunits of the GABA, NMDA and AMPA receptors, as well as the expression of the CB1 receptor, and that of enzymes related to the biosynthesis and degradation of endocannabinoids. Moreover, two synaptic scaffold proteins related to GABA and NMDA receptors, gephyrin and PSD-95, were quantified in Western blots. Significant interactions between cocaine and alcohol were common, affecting the GABAergic and endocannabinoid systems in the medial prefrontal cortex and amygdala of young adults, whereas such interactions were evident in the glutamatergic and endocannabinoid systems in adults, as well as a more pronounced sex effect. Significant interactions between these drugs affecting the scaffold proteins were evident in the medial prefrontal cortex and nucleus accumbens of young adults, and in the nucleus accumbens and amygdala of adults, but not in the hippocampus. These results highlight the importance of considering the interactions between cocaine and alcohol on neurotransmitter systems in the context of polyconsumption, specifically when treating problems of abuse of these two substances.
Gnathodiaphyseal dysplasia (GDD) is an autosomal dominant syndrome characterized by frequent bone fractures at a young age, bowing of tubular bones and cemento-osseus lesions of the jawbones. Anoctamin 5 (ANO5) belongs to the anoctamin protein family that includes calcium-activated chloride channel
s. However, recent data together with our own experiments reported here add weight to the hypothesis that ANO5 may not function as calcium-activated chloride channel. By sequencing the entire ANO5 gene coding region and untranslated regions in a large Italian GDD family, we found a novel missense mutation causing the p.Thr513Ile substitution. The mutation segregates with the disease in the family and has never been described in any database as a polymorphism. To date, only two mutations on the same cysteine residue at position 356 of ANO5 amino-acid sequence have been described in GDD families. As ANO5 has also been found to be mutated in two different forms of muscular dystrophy, the finding of this third mutation in GDD adds clues to the role of ANO5 in these disorders.
Marconi A, etal., Exp Dermatol. 2015 May;24(5):396-8. doi: 10.1111/exd.12679.
Melanoma is characterized, among other features, by microenvironmental factors and by an altered apoptotic machinery. Melanoma cell response to a hypoxic environment is transcriptionally regulated by the Hypoxia-Inducible Factor (HIF)-1alpha. p75 neurotrophin receptor (p75(NTR) ), also called CD271,
mediates apoptosis in several cell systems. The purpose of this study was to analyze the expression of HIF-1alpha and CD271 in melanomas at different phases of progression, as evaluated by histology and reflectance confocal microscopy (RCM). By RCM, 41.67% tumors were characterized by the presence of a population of dendritic and pleomorphic cells (D+P), corresponding to in situ melanoma; 25% exhibited a predominantly round-cell (RN) proliferation with histologic features of superficial melanoma, and 33.33% showed the presence of cells aggregated in nests (DN), typical of invasive melanoma. HIF-1alpha was scarcely detected in D+P and in RN melanomas, while it was highly expressed in DN tumors. By contrast, CD271 positive cells were mostly detected in D+P population, and barely observed in the other subtypes. This work demonstrates that CD271 expression inversely correlates with hypoxia in melanoma, and that the two markers may be used in the future as diagnostic/prognostic tools for this neoplasm.
Marconi C, etal., Blood. 2019 Mar 21;133(12):1346-1357. doi: 10.1182/blood-2018-07-859496. Epub 2018 Dec 27.
Inherited thrombocytopenias (ITs) are a heterogeneous group of disorders characterized by low platelet count that may result in bleeding tendency. Despite progress being made in defining the genetic causes of ITs, nearly 50% of patients with familial thrombocytopenia are affected with forms of unkno
wn origin. Here, through exome sequencing of 2 siblings with autosomal-recessive thrombocytopenia, we identified biallelic loss-of-function variants in PTPRJ . This gene encodes for a receptor-like PTP, PTPRJ (or CD148), which is expressed abundantly in platelets and megakaryocytes. Consistent with the predicted effects of the variants, both probands have an almost complete loss of PTPRJ at the messenger RNA and protein levels. To investigate the pathogenic role of PTPRJ deficiency in hematopoiesis in vivo, we carried out CRISPR/Cas9-mediated ablation of ptprja (the ortholog of human PTPRJ) in zebrafish, which induced a significantly decreased number of CD41+ thrombocytes in vivo. Moreover, megakaryocytes of our patients showed impaired maturation and profound defects in SDF1-driven migration and formation of proplatelets in vitro. Silencing of PTPRJ in a human megakaryocytic cell line reproduced the functional defects observed in patients' megakaryocytes. The disorder caused by PTPRJ mutations presented as a nonsyndromic thrombocytopenia characterized by spontaneous bleeding, small-sized platelets, and impaired platelet responses to the GPVI agonists collagen and convulxin. These platelet functional defects could be attributed to reduced activation of Src family kinases. Taken together, our data identify a new form of IT and highlight a hitherto unknown fundamental role for PTPRJ in platelet biogenesis.
OBJECTIVE: Neuropsychological problems occurrence varies among childhood cancer survivors, and associated risk factors have not been fully deciphered. We wanted to study the role of genetic variants in behavioral problems in this population. STUDY DESIGN: Behavioral problems in pediatric acute lym
phoblastic leukemia patients (n=138) were investigated longitudinally, using the Child Behavior Checklist questionnaire and multilevel statistical modeling. Thirty-four candidate polymorphisms, related to anticancer drug effects, were investigated. RESULTS: NOS3 gene functional polymorphisms showed significant association: patients homozygous for the minor allele at investigated loci showed decreased externalizing behavioral problems scores over time (t tests: T-786C n=69, P=0.003; G894T n=71, P=0.065). The effect was even more pronounced for individuals that are homozygous for the -786C844T haplotype (t test, n=69, P<0.001) and results were supported by multilevel modeling analyses (P<0.001). No such association was observed for internalizing behavioral problems. CONCLUSION: NOS3 variants modulate externalizing problems individual trajectories, likely in relationship with glucocorticoid exposure.
Marcora E and Kennedy MB, Hum Mol Genet. 2010 Nov 15;19(22):4373-84. Epub 2010 Aug 25.
Expansion of a polyglutamine (polyQ) tract in the Huntingtin (Htt) protein causes Huntington's disease (HD), a fatal inherited neurodegenerative disorder. Loss of the normal function of Htt is thought to be an important pathogenetic component of HD. However, the function of wild-type Htt is not wel
l defined. Htt is thought to be a multifunctional protein that plays distinct roles in several biological processes, including synaptic transmission, intracellular transport and neuronal transcription. Here, we show with biochemical and live cell imaging studies that wild-type Htt stimulates the transport of nuclear factor kappa light-chain-enhancer of activated B cells (NF-kappaB) out of dendritic spines (where NF-kappaB is activated by excitatory synaptic input) and supports a high level of active NF-kappaB in neuronal nuclei (where NF-kappaB stimulates the transcription of target genes). We show that this novel function of Htt is impaired by the polyQ expansion and thus may contribute to the etiology of HD.
Marcocci E, etal., Nephrol Dial Transplant. 2009 May;24(5):1464-71. doi: 10.1093/ndt/gfn681. Epub 2009 Jan 7.
BACKGROUND: Alport syndrome is a clinically and genetically heterogeneous nephropathy characterized by glomerular basement membrane lesions often associated with hearing loss and ocular anomalies. While the X-linked and the autosomal recessive forms are well known, the autosomal dominant form is not
well acknowledged. METHODS: We have clinically investigated 38 patients with a diagnosis of autosomal dominant Alport syndrome belonging to eight different families. The analysis of the COL4A4 gene was performed by denaturing high performance liquid chromatography and automated DNA sequencing. RESULTS: In our cohort of patients, only 24.3% (9/37) reached end-stage renal disease, at the mean age of 51.2 years. Four patients had hearing loss (13.3%) and none ocular changes. Molecular analysis revealed eight novel private COL4A4 gene mutations: three frameshift, three missense and two splice-site mutations. CONCLUSIONS: These data indicate autosomal dominant Alport syndrome as a disease with a low risk of ocular and hearing anomalies but with a significant risk to develop renal failure although at an older age than the X-linked form. We were unable to demonstrate a genotype-phenotype correlation. Altogether, these data make difficult the differential diagnosis with the benign familial haematuria due to heterozygous mutations of COL4A4 and COL4A3, especially in young patients, and with the X-linked form of Alport syndrome in families where only females are affected. A correct diagnosis and prognosis is based on a comprehensive clinical investigation in as many family members as possible associated with a broadly formal genetic analysis of the pedigree.
Di Marco F, etal., Pulm Pharmacol Ther. 2010 Jun;23(3):159-64. Epub 2010 Jan 22.
BACKGROUND: Some studies suggest that the sympathetic nervous system and the renin-angiotensin system are activated in patients with chronic obstructive pulmonary disease (COPD), potentially resulting in negative cardiopulmonary and muscular effects. The aim of this pilot study was to evaluate the e
fficacy of an angiotensin converting enzyme (ACE) inhibitor on cardiopulmonary exercise performance in COPD patients. Primary outcome was the effect of treatment on the ventilatory response to exercise (VE/VCO(2) slope). Secondary outcomes were exercise variables evaluated by the cardiopulmonary exercise test, and pulmonary function according to ACE genotyping. METHODS: 4 weeks treatment with enalapril (10 mg od) or placebo was evaluated in 21 COPD patients (FEV(1) < 60%) and without cardiovascular disease in a double-blind, cross-over study. RESULTS: 18 patients completed the study. Enalapril did not exert a significant effect on exercise VE/VCO(2) slope or on peak O(2) consumption. However enalapril significantly improved peak O(2) pulse and work rate compared to placebo. A mild but significant worsening of the diffusion capacity of the lung was observed. ACE genotype did not significantly affect patients' response to treatment, except for a trend toward a more evident effect of treatment in patients with II ACE genotype in terms of O(2) pulse and gas diffusion. CONCLUSIONS: In this pilot study, ACE inhibition did not affect the ventilatory response to exercise in COPD patients. However, treatment resulted in improvement in work rate and O(2) pulse, suggesting that ACE inhibitor therapy warrants consideration and may provide beneficial effect on the cardiovascular response to exercise in COPD.
De Marco P, etal., J Hum Genet. 2006;51(2):98-103. Epub 2005 Nov 29.
Genetic variants of enzymes involved in the folate pathway might be expected to have an impact on neural tube defect (NTD) risk. Given its key role in folate metabolism, the methylenetetrahydrofolate dehydrogenase 1 (MTHFD1) gene could represent an attractive candidate in NTD aetiology. In this stud
y, the impact of the MTHFD1 1958G > A polymorphism on NTD risk in the Italian population was examined both by hospital-based case-control and family-based studies. The MTHFD1 1958G > A polymorphism was genotyped in 142 NTD cases, 125 mothers, 108 fathers and 523 controls. An increased risk was found for the heterozygous 1958G/A (OR = 1.69; P = 0.04) and homozygous 1958A/A (OR = 1.91; P = 0.02) genotypes in the children. Significant association was also found when combined 1958G/A and 1958A/A genotypes of cases were compared with the 1958G/G genotype (OR = 1.76; P = 0.02). The risk of an NTD-affected pregnancy of the mothers was increased 1.67-fold (P = 0.04) only when a dominant effect (1958G/A or 1958A/A vs 1958G/G) of the 1958A allele was analysed. The combined TDT/1-TDT (Z = 2.11; P = 0.03) and FBAT (Z = 2.4; P = 0.01) demonstrated a significant excess of transmission of the 1958A allele to affected individuals. In summary, our results indicate that heterozygosity and homozygosity for the MTHFD1 1958G > A polymorphism are genetic determinants of NTD risk in the cases examined.
De Marco G, etal., J Clin Endocrinol Metab. 2011 Aug;96(8):E1335-9. doi: 10.1210/jc.2010-2467. Epub 2011 May 11.
CONTEXT: Congenital hypothyroidism (CH) associated with goiter or a gland of normal size has been linked to dual oxidase 2 (DUOX2) mutations in the presence of iodide organification defect. OBJECTIVE: Thirty unrelated children with CH or subclinical hypothyroidism (SH) identified during infancy wit
h a eutopic thyroid gland, coming from our Screening Centre for CH or referred from other regions of Italy, were studied with the perchlorate discharge test to identify organification defects. Eleven children with iodide organification defect were considered for the genetic analysis of TPO, DUOX2, and dual oxidase maturation factor 2 (DUOXA2) genes. PATIENTS: Eight children with CH and three with SH and eutopic thyroid gland were included in the study. After discontinuation of therapy, a partial or complete organification defect was shown after (1)(2)(3)I scintigraphy and perchlorate test. METHODS: TPO, DUOX2, and DUOXA2 genes were analyzed, and functional activity of DUOX2 variants was studied in HeLa cells. RESULTS: Sequencing of the DUOX2 gene revealed a deletion S965fsX994 in three children; two were euthyroid after 1 month of L-T(4) discontinuation but developed SH after 5 and 18 months, respectively, whereas the other child had SH. One child with SH showed H678R, R701Q, and P982A substitutions, and another child with SH showed only the P982A. One child with SH showed the Y1150C mutation, and another euthyroid child showed the A728T mutation. Functional studies confirmed that S965fsX994, Y1150C, and A728T mutations were responsible for the defect in H(2)O(2) production, whereas H678R, R701Q, and P982A did not alter H(2)O(2) production in vitro. CONCLUSIONS: Genetic analysis of the DUOX2 gene was performed in 11 children with organification defect. Two new mutations (Y1150C and A728T) and the deletion S965FsX994 were responsible for the deficit in the organification process and the phenotypes. Three polymorphisms (H678R, P982A, and R701Q) were identified.
de Marco MC, etal., J Cell Biol 2002 Oct 14;159(1):37-44. Epub 2002 Oct 07.
Transcytosis is used alone (e.g., hepatoma HepG2 cells) or in combination with a direct pathway from the Golgi (e.g., epithelial MDCK cells) as an indirect route for targeting proteins to the apical surface. The raft-associated MAL protein is an essential element of the machinery for the direct rout
e in MDCK cells. Herein, we present the functional characterization of MAL2, a member of the MAL protein family, in polarized HepG2 cells. MAL2 resided selectively in rafts and is predominantly distributed in a compartment localized beneath the subapical F-actin cytoskeleton. MAL2 greatly colocalized in subapical endosome structures with transcytosing molecules en route to the apical surface. Depletion of endogenous MAL2 drastically blocked transcytotic transport of exogenous polymeric immunoglobulin receptor and endogenous glycosylphosphatidylinositol-anchored protein CD59 to the apical membrane. MAL2 depletion did not affect the internalization of these molecules but produced their accumulation in perinuclear endosome elements that were accessible to transferrin. Normal transcytosis persisted in cells that expressed exogenous MAL2 designed to resist the depletion treatment. MAL2 is therefore essential for transcytosis in HepG2 cells.
De Marco C, etal., Oncotarget. 2015 Nov 24;6(37):39634-50. doi: 10.18632/oncotarget.4022.
The hotspot E17K mutation in the pleckstrin homology domain of AKT1 occurs in approximately 0.6-2% of human lung cancers. In this manuscript, we sought to determine whether this AKT1 variant is a bona-fide activating mutation and plays a role in the development of lung cancer. Here we report that i
n immortalized human bronchial epithelial cells (BEAS-2B cells) mutant AKT1-E17K promotes anchorage-dependent and -independent proliferation, increases the ability to migrate, invade as well as to survive and duplicate in stressful conditions, leading to the emergency of cells endowed with the capability to form aggressive tumours at high efficiency. We provide also evidence that the molecular mechanism whereby AKT1-E17K is oncogenic in lung epithelial cells involves phosphorylation and consequent cytoplasmic delocalization of the cyclin-dependent kinase (cdk) inhibitor p27. In agreement with these results, cytoplasmic p27 is preferentially observed in primary NSCLCs with activated AKT and predicts poor survival.
Di Marco V, etal., J Viral Hepat. 2013 Feb;20(2):113-21. doi: 10.1111/j.1365-2893.2012.01637.x. Epub 2012 Jul 25.
Genetic factors can influence the outcome of antiviral therapy in chronic hepatitis C (HCV). We evaluated the role of interleukin-28B single nucleotide polymorphisms (SNPs) and inosine triphosphatase (ITPA) gene variants in HCV cirrhosis treated with Peg-Interferon and ribavirin. A prospective cohor
t of 233 patients with compensated cirrhosis received 1-1.5 mug/kg/week of Peg-Interferon alpha-2b plus 1000-1200 mg/day of RBV for 48 weeks. A sustained virologic response (SVR) was achieved in 27% of patients. On multivariate logistic analysis, the absence of oesophageal varices (OR 3.64 CI 95% 1.27-10.44 P = 0.016), infection with genotype 2 or 3 (OR 4.06, CI 95% 1.08-15.26, P = 0.038), C/C alleles of rs12979860 SNP (OR 7.04, CI 95% 2.40-20.72, P < 0.001) and rapid virologic response (RVR) (OR 78.29, CI 95% 16.07-381.29, P < 0.001) were independently associated with SVR. Patients who experienced post-treatment relapse received lower total doses of Peg-Interferon (52.0 +/- 15.8 mug/kg vs 65.7 +/- 13.3 mug/kg, P < 0.001) and lower total dose of RBV (3829 +/- 1210 mg vs 4709 +/- 954 mg, P < 0.001) than patients who achieved an SVR. ITPA variants predictive of high ITPase activity were associated with reduction of haemoglobin >/=3 g/dL in the first 4 weeks (P < 0.001), and with reduction of haemoglobin <10 g/dL (P = 0.03) on treatment. In conclusion, combination therapy with Peg-Interferon and RBV in patients with HCV cirrhosis must be guided by virus genotype, severity of portal hypertension, favourable IL-28B polymorphisms and ITPA variants, and RVR on treatment.
Diseases involving the distal lung alveolar epithelium include chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and lung adenocarcinoma. Accurate labeling of specific cell types is critical for determining the contribution of each to the pathogenesis of these diseases. The dista
l lung alveolar epithelium is composed of two cell types, alveolar epithelial type 1 (AT1) and type 2 (AT2) cells. Although cell type-specific markers, most prominently surfactant protein C, have allowed detailed lineage tracing studies of AT2 cell differentiation and the cells' roles in disease, studies of AT1 cells have been hampered by a lack of genes with expression unique to AT1 cells. In this study, we performed genome-wide expression profiling of multiple rat organs together with purified rat AT2, AT1, and in vitro differentiated AT1-like cells, resulting in the identification of 54 candidate AT1 cell markers. Cross-referencing with genes up-regulated in human in vitro differentiated AT1-like cells narrowed the potential list to 18 candidate genes. Testing the top four candidate genes at RNA and protein levels revealed GRAM domain 2 (GRAMD2), a protein of unknown function, as highly specific to AT1 cells. RNA sequencing (RNAseq) confirmed that GRAMD2 is transcriptionally silent in human AT2 cells. Immunofluorescence verified that GRAMD2 expression is restricted to the plasma membrane of AT1 cells and is not expressed in bronchial epithelial cells, whereas reverse transcription-polymerase chain reaction confirmed that it is not expressed in endothelial cells. Using GRAMD2 as a new AT1 cell-specific gene will enhance AT1 cell isolation, the investigation of alveolar epithelial cell differentiation potential, and the contribution of AT1 cells to distal lung diseases.
Elucidation of the epigenetic basis for cell-type specific gene regulation is key to gaining a full understanding of how the distinct phenotypes of differentiated cells are achieved and maintained. Here we examined how epigenetic changes are integrated with transcriptional activation to determine ce
ll phenotype during differentiation. We performed epigenomic profiling in conjunction with transcriptomic profiling using in vitro differentiation of human primary alveolar epithelial cells (AEC). This model recapitulates an in vivo process in which AEC transition from one differentiated cell type to another during regeneration following lung injury. Interrogation of histone marks over time revealed enrichment of specific transcription factor binding motifs within regions of changing chromatin structure. Cross-referencing of these motifs with pathways showing transcriptional changes revealed known regulatory pathways of distal alveolar differentiation, such as the WNT and transforming growth factor beta (TGFB) pathways, and putative novel regulators of adult AEC differentiation including hepatocyte nuclear factor 4 alpha (HNF4A), and the retinoid X receptor (RXR) signaling pathways. Inhibition of the RXR pathway confirmed its functional relevance for alveolar differentiation. Our incorporation of epigenetic data allowed specific identification of transcription factors that are potential direct upstream regulators of the differentiation process, demonstrating the power of this approach. Integration of epigenomic data with transcriptomic profiling has broad application for the identification of regulatory pathways in other models of differentiation.
The myeloproliferative sarcoma virus (MPSV) infection in DBA/2 mice leads to important quantitative and qualitative changes in their hemopoiesis. These findings suggest a disturbance in the production and action of a certain hemopoietic factor similar to IL3. Here, we show that the level of the 20 a
lpha-hydroxysteroid dehydrogenase (20 alpha-SDH) expression, which can be induced by IL3, is dramatically increased in spleen and thymus of MPSV-infected mice. Our results suggest that quantification of 20 alpha-SDH activity can be used to indicate abnormal production of a growth factor similar to IL3 in hemopoietic system diseases.
Marcolongo P, etal., FEBS Lett. 1998 Oct 2;436(2):247-50.
Glycogen storage disease (GSD) 1b is the deficiency of endoplasmic reticulum glucose-6-phosphate (G6P) transport. We here report the structure of the gene encoding a protein likely to be responsible for G6P transport, and its mapping to human chromosome 11q23.3. The gene is composed of nine exons sp
anning a genomic region of approximately 4 kb. Primers based on the genomic sequence were used in single strand conformation polymorphism (SSCP) analysis and mutations were found in six out of seven GSD 1b patients analysed.
In order to determine whether or not CFTR protein distribution differs between the airways of fetuses with Cystic Fibrosis (CF) from the airways of normal fetuses we studied the distribution pattern of the CFTR protein in lung. Cases of normal and CF human fetuses as well as cases of normal neonates
were examinated. Our aim was to establish whether CFTR expression during pregnancy could be correlated with the maturation of the airways, and to compare normal and CF samples. We hypothesized that any difference between normal and CF fetal lung in CFTR protein expression could be related to a functional change appearing in early development even if no morphological differences could be detected at the light microscopic level. The distribution of CFTR protein progressively increased from 10 weeks of gestation (WG) to mid-gestation, but thereafter decreased until term. The CFTR protein was first detected in the cytoplasm of undifferentiated epithelial cells. Before mid-gestation, the immunostaining was strongly positive in bronchi, in sub-mucosal glands, and in lung parenchyma. Then, it became localized to the apical zone of the epithelial cells. This pattern correlated with differentiation during the second half of gestation. The main difference observed between normal and CF fetuses was a 3-week delay in detectability of the CFTR protein expression in the latter until 15 weeks of gestation. These results support the hypothesis of an early functional change. Abnormal fetal lung CFTR protein regulation could give rise to a predisposition to the post-natal inflammatory changes of the airways that characterize CF disease.
Marcogliese PC, etal., Am J Hum Genet. 2018 Aug 2;103(2):245-260. doi: 10.1016/j.ajhg.2018.07.006. Epub 2018 Jul 26.
Interferon regulatory factor 2 binding protein-like (IRF2BPL) encodes a member of the IRF2BP family of transcriptional regulators. Currently the biological function of this gene is obscure, and the gene has not been associated with a Mendelian disease. Here we describe seven individuals who carry da
maging heterozygous variants in IRF2BPL and are affected with neurological symptoms. Five individuals who carry IRF2BPL nonsense variants resulting in a premature stop codon display severe neurodevelopmental regression, hypotonia, progressive ataxia, seizures, and a lack of coordination. Two additional individuals, both with missense variants, display global developmental delay and seizures and a relatively milder phenotype than those with nonsense alleles. The IRF2BPL bioinformatics signature based on population genomics is consistent with a gene that is intolerant to variation. We show that the fruit-fly IRF2BPL ortholog, called pits (protein interacting with Ttk69 and Sin3A), is broadly detected, including in the nervous system. Complete loss of pits is lethal early in development, whereas partial knockdown with RNA interference in neurons leads to neurodegeneration, revealing a requirement for this gene in proper neuronal function and maintenance. The identified IRF2BPL nonsense variants behave as severe loss-of-function alleles in this model organism, and ectopic expression of the missense variants leads to a range of phenotypes. Taken together, our results show that IRF2BPL and pits are required in the nervous system in humans and flies, and their loss leads to a range of neurological phenotypes in both species.
Garcia-Marcos M, etal., J Lipid Res. 2006 Apr;47(4):705-14. Epub 2006 Jan 16.
The plasma membrane of cells from rat submandibular glands was isolated and extensively sonicated. The homogenate was centrifuged at high speed in a discontinuous sucrose gradient. Light fractions contained vesicles analogous to rafts: they were rich in cholesterol, they contained GM1 and caveolin-1
, and P2X7 receptors were detected in these fractions. The location of the P2X7 receptors in rafts was abolished when cellular cholesterol was removed by methyl-beta-cyclodextrin (MCD). ATP activated neutral sphingomyelinase (N-SMase), which provoked a decrease of the cellular content of sphingomyelin and an increase of ceramide levels in these cells and in the rafts. Treatment with MCD and filipin (but not with alpha-cyclodextrin) abolished the increase of the intracellular concentration of calcium ([Ca2+]i) in response to epinephrine but not to ATP. MCD and filipin also inhibited the activation by ATP of phospholipase A2 (PLA2). Inhibition of N-SMase with glutathione or GW4869 prevented the activation of PLA2 by P2X7 agonists without affecting [Ca2+]i levels. We conclude that P2X7 receptors are present in both raft and nonraft compartments of plasma membranes; the receptors forming a nonselective cation channel are located in the nonraft fraction. P2X7 receptors in the rafts are coupled to the activation of N-SMase, which increases the content of ceramides in rafts. This may contribute to the activation of PLA2 in response to P2X7 receptor occupancy.
Garcia-Marcos M, etal., J Biol Chem. 2011 Aug 12;286(32):28138-49. doi: 10.1074/jbc.M110.204099. Epub 2011 Jun 8.
Heterotrimeric G proteins are molecular switches modulated by families of structurally and functionally related regulators. GIV (Gα-interacting vesicle-associated protein) is the first non-receptor guanine nucleotide exchange factor (GEF) that activates Gα(i) subunits via a defined, evol
utionarily conserved motif. Here we found that Calnuc and NUCB2, two highly homologous calcium-binding proteins, share a common motif with GIV for Gα(i) binding and activation. Bioinformatics searches and structural analysis revealed that Calnuc and NUCB2 possess an evolutionarily conserved motif with sequence and structural similarity to the GEF sequence of GIV. Using in vitro pulldown and competition assays, we demonstrate that this motif binds preferentially to the inactive conformation of Gα(i1) and Gα(i3) over other Gα subunits and, like GIV, docks onto the α3/switch II cleft. Calnuc binding was impaired when Lys-248 in the α3 helix of Gα(i3) was replaced with M, the corresponding residue in Gα(o), which does not bind to Calnuc. Moreover, mutation of hydrophobic residues in the conserved motif predicted to dock on the α3/switch II cleft of Gα(i3) impaired the ability of Calnuc and NUCB2 to bind and activate Gα(i3) in vitro. We also provide evidence that calcium binding to Calnuc and NUCB2 abolishes their interaction with Gα(i3) in vitro and in cells, probably by inducing a conformational change that renders the Gα(i)-binding residues inaccessible. Taken together, our results identify a new type of Gα(i)-regulatory motif named the GBA motif (for Gα-binding and -activating motif), which is conserved across different proteins throughout evolution. These findings provide the structural basis for the properties of Calnuc and NUCB2 binding to Gα subunits and its regulation by calcium ions.
Garcia-Marcos M, etal., Proc Natl Acad Sci U S A. 2009 Mar 3;106(9):3178-83. doi: 10.1073/pnas.0900294106. Epub 2009 Feb 11.
Heterotrimeric G proteins are molecular switches that control signal transduction. Ligand-occupied, G protein-coupled receptors serve as the canonical guanine nucleotide exchange factors (GEFs) that activate heterotrimeric G proteins. A few unrelated nonreceptor GEFs have also been described, but li
ttle or nothing is known about their structure, mechanism of action, or cellular functions in mammals. We have discovered that GIV/Girdin serves as a nonreceptor GEF for G alpha i through an evolutionarily conserved motif that shares sequence homology with the synthetic GEF peptide KB-752. Using the available structure of the KB-752 x G alpha i1 complex as a template, we modeled the G alpha i-GIV interface and identified the key residues that are required to form it. Mutation of these key residues disrupts the interaction and impairs Akt enhancement, actin remodeling, and cell migration in cancer cells. Mechanistically, we demonstrate that the GEF motif is capable of activating as well as sequestering the G alpha-subunit, thereby enhancing Akt signaling via the G betagamma-PI3K pathway. Recently, GIV has been implicated in cancer metastasis by virtue of its ability to enhance Akt activity and remodel the actin cytoskeleton during cancer invasion. Thus, the novel regulatory motif described here provides the structural and biochemical basis for the prometastatic features of GIV, making the functional disruption of this unique G alpha i-GIV interface a promising target for therapy against cancer metastasis.
Marcos-Villar L, etal., J Virol. 2016 Jan 20;90(7):3694-707. doi: 10.1128/JVI.00053-16.
Influenza A virus requires ongoing cellular transcription to carry out the cap-snatching process. Chromatin remodelers modify chromatin structure to produce an active or inactive conformation, which enables or prevents the recruitment of transcriptional complexes to specific genes; viral transcript
ion thus depends on chromatin dynamics. Influenza virus polymerase associates with chromatin components of the infected cell, such as RNA polymerase II (RNAP II) or the CHD6 chromatin remodeler. Here we show that another CHD family member, CHD1 protein, also interacts with the influenza virus polymerase complex. CHD1 recognizes the H3K4me3 (histone 3 with a trimethyl group in lysine 4) histone modification, a hallmark of active chromatin. Downregulation of CHD1 causes a reduction in viral polymerase activity, viral RNA transcription, and the production of infectious particles. Despite the dependence of influenza virus on cellular transcription, RNAP II is degraded when viral transcription is complete, and recombinant viruses unable to degrade RNAP II show decreased pathogenicity in the murine model. We describe the CHD1-RNAP II association, as well as the parallel degradation of both proteins during infection with viruses showing full or reduced induction of degradation. The H3K4me3 histone mark also decreased during influenza virus infection, whereas a histone mark of inactive chromatin, H3K27me3, remained unchanged. Our results indicate that CHD1 is a positive regulator of influenza virus multiplication and suggest a role for chromatin remodeling in the control of the influenza virus life cycle. IMPORTANCE: Although influenza virus is not integrated into the genome of the infected cell, it needs continuous cellular transcription to synthesize viral mRNA. This mechanism implies functional association with host genome expression and thus depends on chromatin dynamics. Influenza virus polymerase associates with transcription-related factors, such as RNA polymerase II, and with chromatin remodelers, such as CHD6. We identified the association of viral polymerase with another chromatin remodeler, the CHD1 protein, which positively modulated viral polymerase activity, viral RNA transcription, and virus multiplication. Once viral transcription is complete, RNAP II is degraded in infected cells, probably as a virus-induced mechanism to reduce the antiviral response. CHD1 associated with RNAP II and paralleled its degradation during infection with viruses that induce full or reduced degradation. These findings suggest that RNAP II degradation and CHD1 degradation cooperate to reduce the antiviral response.
INTRODUCTION: Neurofibromatosis type 1 (NF1) is a progressive multisystem disorder following an autosomal dominant inheritance pattern that presents with multiple neurological manifestations. METHODS: We reviewed medical histories of patients with NF1 followed up at our hospital
's paediatric neurology department from May 1990 to 31 December 2018. We collected data on neurological symptoms. RESULTS: A total of 128 patients with NF1 were identified. Mean age (SD) at NF1 diagnosis was 4.43 (3.38) years (range, 0.5-14.5 years). There was a slight female predominance (53.1%). Macrocephaly (head circumference over 2 SDs above average for age) was present in 37.5% of cases. Attention-deficit/hyperactivity disorder was recorded in 28.9% of patients (37): combined type in 20 patients, predominantly inattentive in 15, and predominantly impulsive/hyperactive in 2. Other manifestations included headache (18.6%), cognitive impairment (7.8%), motor deficit (6.2%), and epilepsy (4.68%). Brain MRI was performed in 85 patients, revealing T2-weighted hyperintensities in the basal ganglia and/or cerebellum in 60 patients (70.5%), Chiari malformation type 1 in 4 cases, and arachnoid cysts in 3. Optic nerve gliomas were identified by MRI in 22 patients (25.8%). Other MRI findings included plexiform neurofibromas (9.3%) and central nervous system gliomas (3.1%). CONCLUSIONS: The neurological manifestations identified in our sample are consistent with those reported in the literature. Effective transfer strategies from paediatric neurology departments and subsequent clinical follow-up by adult neurology departments are needed to prevent loss to follow-up in adulthood.
Duriez B, etal., Proc Natl Acad Sci U S A. 2007 Feb 27;104(9):3336-41. doi: 10.1073/pnas.0611405104. Epub 2007 Feb 20.
Thioredoxins belong to a large family of enzymatic proteins that function as general protein disulfide reductases, therefore participating in several cellular processes via redox-mediated reactions. So far, none of the 18 members of this family has been involved in human pathology. Here we identifie
d TXNDC3, which encodes a thioredoxin-nucleoside diphosphate kinase, as a gene implicated in primary ciliary dyskinesia (PCD), a genetic condition characterized by chronic respiratory tract infections, left-right asymmetry randomization, and male infertility. We show that the disease, which segregates as a recessive trait, results from the unusual combination of the following two transallelic defects: a nonsense mutation and a common intronic variant found in 1% of control chromosomes. This variant affects the ratio of two physiological TXNDC3 transcripts: the full-length isoform and a novel isoform, TXNDC3d7, carrying an in-frame deletion of exon 7. In vivo and in vitro expression data unveiled the physiological importance of TXNDC3d7 (whose expression was reduced in the patient) and the corresponding protein that was shown to bind microtubules. PCD is known to result from defects of the axoneme, an organelle common to respiratory cilia, embryonic nodal cilia, and sperm flagella, containing dynein arms, with, to date, the implication of genes encoding dynein proteins. Our findings, which identify a another class of molecules involved in PCD, disclose the key role of TXNDC3 in ciliary function; they also point to an unusual mechanism underlying a Mendelian disorder, which is an SNP-induced modification of the ratio of two physiological isoforms generated by alternative splicing.
Ruiz A, etal., Am J Hum Genet. 1998 Jun;62(6):1452-9.
Retinitis pigmentosa (RP) is the most common inherited retinal dystrophy, with extensive allelic and nonallelic genetic heterogeneity. Autosomal recessive RP (arRP) is the most common form of RP worldwide, with at least nine loci known and accountable for approximately 10%-15% of all cases. Gamma-am
inobutyric acid (GABA) is the major inhibitory transmitter in the CNS. Different GABA receptors are expressed in all retinal layers, and inhibition mediated by GABA receptors in the human retina could be related to RP. We have selected chromosomal regions containing genes that encode the different subunits of the GABA receptors, for homozygosity mapping in inbred families affected by arRP. We identify a new locus for arRP, on chromosome 6, between markers D6S257 and D6S1644. Our data suggest that 10%-20% of Spanish families affected by typical arRP could have linkage to this new locus. This region contains subunits GABRR1 and GABRR2 of the GABA-C receptor, which is the effector of lateral inhibition at the retina.
Gleeson FC, etal., Oncotarget. 2017 Jun 28;8(55):93464-93475. doi: 10.18632/oncotarget.18750. eCollection 2017 Nov 7.
BACKGROUND: Recent genetic studies have highlighted that alterations in MEN1, chromatin remodeling genes, and mammalian target of rapamycin (mTOR) pathway genes are the most frequent molecular events identified in pancreas neuroendocrine tumors (pNETs). The prognostic or predictive impact
of these biomarkers and other less frequently observed aberrations, i.e. PTEN, TSC2 and PIK3CA are relatively unknown. The aims of this targeted next generation sequencing (NGS) study were to assess tumor cytology genotype diversity, to survey for potential adverse prognostic biomarkers and the prevalence of mTOR pathway variants. METHODS: Using a custom 15 gene gastroenteropancreatic neuroendocrine tumor panel, targeted NGS of archived (2002-2013) primary pNETs (n=90) and pNET liver metastasis (n=32) cytology smears was performed. RESULTS: The genetic variant landscape revealed that 21% and 28% of primary and metastatic liver pNETs harbored >= 2 variants per tumor, respectively. The most prevalent primary tumor variants were in the MEN1 (42%), DAXX (11%), ATRX (10%), and TSC2 (8%) genes. Patients harboring aberrations in TSC2, KRAS or TP53 were more likely to experience disease progression and reduced overall survival, when compared to individuals who were wild-type. The prevalence of these potential prognostic biomarkers in early disease was observed in 3.3% of the primary tumor cohort. mTOR pathway variants including alterations in PTEN, TSC2 and PIK3CA were identified in 10% and 12.5% of primary tumors and pNET liver metastasis, respectively. CONCLUSION: Cytology based tumor genotyping revealed a broad spectrum of genetic variants including possible adverse prognostic biomarkers, reflective of an aggressive phenotype. It also demonstrated the prevalence of potential predictive biomarkers for mTOR pathway inhibitor sensitivity.
Dewachter L, etal., Eur Respir J. 2009 Nov;34(5):1100-10. Epub 2009 Mar 26.
Mutations in the gene encoding bone morphogenetic protein (BMP) receptor type 2 (BMPR-2) have been reported in pulmonary arterial hypertension (PAH), but their functional relevance remains incompletely understood. BMP receptor expression was evaluated in human lungs and in cultured pulmonary artery
smooth muscle cells (PASMCs) isolated from 19 idiopathic PAH patients and nine heritable PAH patients with demonstrated BMPR-2 mutations. BMP4-treated PASMCs were assessed for Smad and p38 mitogen-activated protein kinase (MAPK) signalling associated with mitosis and apoptosis. Lung tissue and PASMCs from heritable PAH patients presented with decreased BMPR-2 expression and variable increases in BMPR-1A and BMPR-1B expression, while a less important decreased BMPR-2 expression was observed in PASMCs from idiopathic PAH patients. Heritable PAH PASMCs showed no increased phosphorylation of Smad1/5/8 in the presence of BMP4, which actually activated the p38MAPK pathway. Individual responses varied from one mutation to another. PASMCs from PAH patients presented with an in vitro proliferative pattern, which could be inhibited by BMP4 in idiopathic PAH but not in heritable PAH. PASMCs from idiopathic PAH and more so from heritable PAH presented an inhibition of BMP4-induced apoptosis. Most heterogeneous BMPR-2 mutations are associated with defective Smad signalling compensated for by an activation of p38MAPK signalling, accounting for PASMC proliferation and deficient apoptosis.
Wan F, etal., Am J Physiol Heart Circ Physiol. 2015 Dec 1;309(11):H1883-93. doi: 10.1152/ajpheart.00594.2015. Epub 2015 Oct 9.
The activation of the calpain system is involved in the repair process following myocardial infarction (MI). However, the impact of the inhibition of calpain by calpastatin, its natural inhibitor, on scar healing and left ventricular (LV) remodeling is elusive. Male mice ubiquitously overexpressing
calpastatin (TG) and wild-type (WT) controls were subjected to an anterior coronary artery ligation. Mortality at 6 wk was higher in TG mice (24% in WT vs. 44% in TG, P < 0.05) driven by a significantly higher incidence of cardiac rupture during the first week post-MI, despite comparable infarct size and LV dysfunction and dilatation. Calpain activation post-MI was blunted in TG myocardium. In TG mice, inflammatory cell infiltration and activation were reduced in the infarct zone (IZ), particularly affecting M2 macrophages and CD4(+) T cells, which are crucial for scar healing. To elucidate the role of calpastatin overexpression in macrophages, we stimulated peritoneal macrophages obtained from TG and WT mice in vitro with IL-4, yielding an abrogated M2 polarization in TG but not in WT cells. Lymphopenic Rag1(-/-) mice receiving TG splenocytes before MI demonstrated decreased T-cell recruitment and M2 macrophage activation in the IZ day 5 after MI compared with those receiving WT splenocytes. Calpastatin overexpression prevented the activation of the calpain system after MI. It also impaired scar healing, promoted LV rupture, and increased mortality. Defective scar formation was associated with blunted CD4(+) T-cell and M2-macrophage recruitment.
IMPORTANCE: Trastuzumab is a life-saving therapy but is associated with symptomatic and asymptomatic left ventricular ejection fraction (LVEF) decline. We report the cardiac toxic effects of a nonanthracycline and trastuzumab-based treatment for patients with early-stage human epidermal growth facto
r receptor 2 (ERBB2, formerly HER2 or HER2/neu)-positive breast cancer. OBJECTIVE: To determine the cardiac safety of paclitaxel with trastuzumab and the utility of LVEF monitoring in patients with node-negative, ERBB2-positive breast cancer. DESIGN, SETTING, AND PARTICIPANTS: In this secondary analysis of an uncontrolled, single group study across 14 medical centers, enrollment of 406 patients with node-negative, ERBB2-positive breast cancer 3 cm, or smaller, and baseline LVEF of greater than or equal to 50% occurred from October 9, 2007, to September 3, 2010. Patients with a micrometastasis in a lymph node were later allowed with a study amendment. Median patient age was 55 years, 118 (29%) had hypertension, and 30 (7%) had diabetes. Patients received adjuvant paclitaxel for 12 weeks with trastuzumab, and trastuzumab was continued for 1 year. Median follow-up was 4 years. INTERVENTIONS: Treatment consisted of weekly 80-mg/m2 doses of paclitaxel administered concurrently with trastuzumab intravenously for 12 weeks, followed by trastuzumab monotherapy for 39 weeks. During the monotherapy phase, trastuzumab could be administered weekly 2-mg/kg or every 3 weeks as 6-mg/kg. Radiation and hormone therapy were administered per standard guidelines after completion of the 12 weeks of chemotherapy. Patient LVEF was assessed at baseline, 12 weeks, 6 months, and 1 year. MAIN OUTCOMES AND MEASURES: Cardiac safety data, including grade 3 to 4 left ventricular systolic dysfunction (LVSD) and significant asymptomatic LVEF decline, as defined by our study, were reported. RESULTS: Overall, 2 patients (0.5%) (95% CI, 0.1%-1.8%) developed grade 3 LVSD and came off study, and 13 (3.2%) (95% CI, 1.9%-5.4%) had significant asymptomatic LVEF decline, 11 of whom completed study treatment. Median LVEF at baseline was 65%; 12 weeks, 64%; 6 months, 64%; and 1 year, 64%. CONCLUSIONS AND RELEVANCE: Cardiac toxic effects from paclitaxel with trastuzumab, manifesting as grade 3 or 4 LVSD or asymptomatic LVEF decline, were low. Patient LVEF was assessed at baseline, 12 weeks, 6 months, and 1 year, and our findings suggest that LVEF monitoring during trastuzumab therapy without anthracyclines could be simplified for many individuals.
BACKGROUND: Pulmonary arterial hypertension (PH), whether idiopathic or related to underlying diseases such as HIV infection, results from complex vessel remodeling involving both pulmonary artery smooth muscle cell (PA-SMC) proliferation and inflammation. CCR5, a coreceptor for cellular HIV-1 entry
expressed on macrophages and vascular cells, may be involved in the pathogenesis of PH. Maraviroc is a new CCR5 antagonist designed to block HIV entry. METHODS AND RESULTS: Marked CCR5 expression was found in lungs from patients with idiopathic PH, in mice with hypoxia-induced PH, and in Simian immunodeficiency virus-infected macaques, in which it was localized chiefly in the PA-SMCs. To assess the role for CCR5 in experimental PH, we used both gene disruption and pharmacological CCR5 inactivation in mice. Because maraviroc does not bind to murine CCR5, we used human-CCR5ki mice for pharmacological and immunohistochemical studies. Compared with wild-type mice, CCR5-/- mice or human-CCR5ki mice treated with maraviroc exhibited decreased PA-SMC proliferation and recruitment of perivascular and alveolar macrophages during hypoxia exposure. CCR5-/- mice reconstituted with wild-type bone marrow cells and wild-type mice reconstituted with CCR5-/- bone marrow cells were protected against PH, suggesting CCR5-mediated effects on PA-SMCs and macrophage involvement. The CCR5 ligands CCL5 and the HIV-1 gp120 protein increased intracellular calcium and induced growth of human and human-CCR5ki mouse PA-SMCs; maraviroc inhibited both effects. Maraviroc also reduced the growth-promoting effects of conditioned media from CCL5-activated macrophages derived from human-CCR5ki mice on PA-SMCs from wild-type mice. CONCLUSION: The CCL5-CCR5 pathway represents a new therapeutic target in PH associated with HIV or with other conditions.
Current studies evidence the role of miRNAs in extracellular vesicles (EVs) as key regulators of pathological processes, including neuroinflammation and neurodegeneration. As EVs can cross the blood-brain barrier, and EV miRNAs are very stable in peripheral circulation, we evaluated the potential ge
nder differences in inflammatory-regulated miRNAs levels in human and murine plasma EVs derived from alcohol-intoxicated female and male adolescents, and whether these miRNAs could be used as biomarkers of neuroinflammation. We demonstrated that while alcohol intoxication lowers anti-inflammatory miRNA (mir-146a-5p, mir-21-5p, mir-182-5p) levels in plasma EVs from human and mice female adolescents, these EV miRNAs increased in males. In mice brain cortices, ethanol treatment lowers mir-146a-5p and mir-21-5p levels, while triggering a higher expression of inflammatory target genes (Traf6, Stat3, and Camk2a) in adolescent female mice. These results indicate, for the first time, that female and male adolescents differ as regards the ethanol effects associated with the inflammatory-related plasma miRNAs EVs profile, and suggest that female adolescents are more vulnerable than males to the inflammatory effects of binge alcohol drinking. These findings also support the view that circulating miRNAs in EVs could be useful biomarkers for screening ethanol-induced neuroinflammation and brain damage in adolescence.
Perche O, etal., Eur J Med Genet. 2013 Nov;56(11):635-41. doi: 10.1016/j.ejmg.2013.07.007. Epub 2013 Sep 4.
7qter deletion syndrome includes prenatal and/or postnatal growth retardation, microcephaly, psychomotor delay or mental retardation and a characteristic dysmorphism. If clinical features are well described, the molecular mechanisms underlying the 7qter deletion syndrome remain unknown. Those deleti
ons usually arise de novo. Here, we describe a young boy with an abnormal phenotype consistent with a 7qter deletion syndrome. High resolution genomic analysis (Affymetrix Human Genome Wide SNP 6.0) revealed a 7q36.3 deletion encompassing NCAPG2, ESYT2, WDR60 and VIPR2, inherited from his asymptomatic father and paternal grandfather. In addition, the patient also harbored a MCPH1 deletion inherited from his healthy mother. Combined NCAPG2 and MCPH1 deletions were correlated with low mRNA levels and protein expression in the patient. MCPH1 and NCAPG2 proteins interaction is known to control chromosome structure and we thus propose that double heterozygosity for null mutations of those two genes of the Condensin II system contribute to mental deficiency with severe microcephaly phenotype.
Loizidou M, etal., Clin Genet. 2007 Feb;71(2):165-70.
In Cyprus, the prevalence of breast cancer associated with BRCA1 and BRCA2 mutations in young women is unknown. In this study, we present the results of mutational analysis of the BRCA1 and BRCA2 genes in 26 Cypriot women diagnosed with breast cancer by the age of 40. The entire coding regions, incl
uding splice sites, of the BRCA1 and BRCA2 genes were sequenced using cycle sequencing. We identified four pathogenic mutations: two in BRCA1 [c.1840A>T (K614X), c.5310delG (5429delG)] and two in BRCA2 [c.3531-3534delCAGC (3758del4), c.8755delG (8984delG)] in six of 26 unrelated patients. The BRCA2 mutation c.3531-3534delCAGC (3758del4) is novel and the BRCA1 mutation c.1840A>T (K614X) is reported for the first time in Cypriot patients. The BRCA2 Cypriot founder mutation c.8755delG (8984delG) was detected in three unrelated patients. Additionally, we identified one novel BRCA1 missense mutation, two novel polymorphisms and three novel intronic variants of which BRCA1 c.4185+3A>G (IVS12+3A>G) may be pathogenic. Of the six BRCA1/2 mutation carriers, only four had a family history. These results show that the prevalence of BRCA1 and BRCA2 mutations in Cypriot women diagnosed with early-onset breast cancer is high. We conclude that Cypriot women with early-onset breast cancer should be offered BRCA1/2 testing irrespective of their family history.
Rodger C, etal., Am J Hum Genet. 2020 Dec 3;107(6):1129-1148. doi: 10.1016/j.ajhg.2020.10.012. Epub 2020 Nov 12.
The endosomal sorting complexes required for transport (ESCRTs) are essential for multiple membrane modeling and membrane-independent cellular processes. Here we describe six unrelated individuals with de novo missense variants affecting the ATPase domain of VPS4A, a critical enzyme regulating ESCRT
function. Probands had structural brain abnormalities, severe neurodevelopmental delay, cataracts, growth impairment, and anemia. In cultured cells, overexpression of VPS4A mutants caused enlarged endosomal vacuoles resembling those induced by expression of known dominant-negative ATPase-defective forms of VPS4A. Proband-derived fibroblasts had enlarged endosomal structures with abnormal accumulation of the ESCRT protein IST1 on the limiting membrane. VPS4A function was also required for normal endosomal morphology and IST1 localization in iPSC-derived human neurons. Mutations affected other ESCRT-dependent cellular processes, including regulation of centrosome number, primary cilium morphology, nuclear membrane morphology, chromosome segregation, mitotic spindle formation, and cell cycle progression. We thus characterize a distinct multisystem disorder caused by mutations affecting VPS4A and demonstrate that its normal function is required for multiple human developmental and cellular processes.
James LI, etal., Nat Chem Biol. 2013 Mar;9(3):184-91. doi: 10.1038/nchembio.1157. Epub 2013 Jan 6.
We describe the discovery of UNC1215, a potent and selective chemical probe for the methyllysine (Kme) reading function of L3MBTL3, a member of the malignant brain tumor (MBT) family of chromatin-interacting transcriptional repressors. UNC1215 binds L3MBTL3 with a K(d) of 120 nM, competitively displ
acing mono- or dimethyllysine-containing peptides, and is greater than 50-fold more potent toward L3MBTL3 than other members of the MBT family while also demonstrating selectivity against more than 200 other reader domains examined. X-ray crystallography identified a unique 2:2 polyvalent mode of interaction between UNC1215 and L3MBTL3. In cells, UNC1215 is nontoxic and directly binds L3MBTL3 via the Kme-binding pocket of the MBT domains. UNC1215 increases the cellular mobility of GFP-L3MBTL3 fusion proteins, and point mutants that disrupt the Kme-binding function of GFP-L3MBTL3 phenocopy the effects of UNC1215 on localization. Finally, UNC1215 was used to reveal a new Kme-dependent interaction of L3MBTL3 with BCLAF1, a protein implicated in DNA damage repair and apoptosis.
Abd El-Aziz MM, etal., Ophthalmic Res. 2006;38(1):19-23. Epub 2005 Sep 23.
To identify the disease gene in 6 Spanish families with autosomal recessive retinitis pigmentosa linked to the RP25 locus, mutation screening of 4 candidate genes, KHDRBS2, PTP4A1, KIAA1411 and OGFRL1, was undertaken based on their expression or functional relevance to the retina. Twenty-six single
nucleotide polymorphisms were identified, of which 14 were novel. Even though no pathological mutations were detected, these genes however remain as good candidates for other retinal degenerations mapping to the same chromosomal region.
The transcription factor Yin Yang 1 (YY1) has an important regulatory role in tumorigenesis, but its implication in thyroid cancer has not been yet investigated. In the present study, we have analyzed the expression of YY1 in differentiated thyroid cancer and assessed the association of YY1 expressi
on with clinical features. Expression of YY1 was evaluated in human thyroid cancer cell lines, a series of matched normal/tumor thyroid tissues and in a thyroid cancer tissue microarray, using real-time PCR, Western blot, and/or immunohistochemistry. YY1 was overexpressed in thyroid cancer cells, at transcription and protein levels. A significant increase of YY1 mRNA was also observed in tumor thyroid tissues. Moreover, immunohistochemical analysis of the thyroid cancer tissue microarray revealed that both papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC) present increased YY1 protein levels (48 and 19%, respectively). After stratification by the level of YY1 protein, positive YY1 expression identifies 88% of patients with PTC. The association of YY1 expression with clinicopathological features in PTC and FTC showed that YY1 expression was related with age at diagnosis. Our data indicates for the first time overexpression of YY1 in differentiated thyroid cancer, with YY1 being more frequently overexpressed in the PTC subtype.
Girard E, etal., Int J Cancer. 2019 Apr 15;144(8):1962-1974. doi: 10.1002/ijc.31921. Epub 2018 Nov 13.
Pathogenic variants in BRCA1 and BRCA2 only explain the underlying genetic cause of about 10% of hereditary breast and ovarian cancer families. Because of cost-effectiveness, multigene panel testing is often performed even if the clinical utility of testing most of the genes remains questionable. Th
e purpose of our study was to assess the contribution of rare, deleterious-predicted variants in DNA repair genes in familial breast cancer (BC) in a well-characterized and homogeneous population. We analyzed 113 DNA repair genes selected from either an exome sequencing or a candidate gene approach in the GENESIS study, which includes familial BC cases with no BRCA1 or BRCA2 mutation and having a sister with BC (N = 1,207), and general population controls (N = 1,199). Sequencing data were filtered for rare loss-of-function variants (LoF) and likely deleterious missense variants (MV). We confirmed associations between LoF and MV in PALB2, ATM and CHEK2 and BC occurrence. We also identified for the first time associations between FANCI, MAST1, POLH and RTEL1 and BC susceptibility. Unlike other associated genes, carriers of an ATM LoF had a significantly higher risk of developing BC than carriers of an ATM MV (ORLoF = 17.4 vs. ORMV = 1.6; p Het = 0.002). Hence, our approach allowed us to specify BC relative risks associated with deleterious-predicted variants in PALB2, ATM and CHEK2 and to add MAST1, POLH, RTEL1 and FANCI to the list of DNA repair genes possibly involved in BC susceptibility. We also highlight that different types of variants within the same gene can lead to different risk estimates.
Pastor IJ, etal., Eur Psychiatry. 2009 Apr;24(3):191-4. doi: 10.1016/j.eurpsy.2008.08.007. Epub 2008 Oct 11.
BACKGROUND: Fyn tyrosine kinase is a member of the Scr family that phosphorylates the NR2A and NR2B subunits of the NMDA receptors reducing the inhibitory effects of ethanol and therefore may regulate the individual sensitivity to ethanol. OBJECTIVES: To investigate whether ther
e is any relationship between the polymorphism at position -93 of the Fyn kinase gene and the susceptibility to develop alcoholism. METHODS: We studied the distribution of genotypes and alleles of the polymorphism -93A/G (137346 T/C) in the 5' UTR region of the fyn gene in 207 male heavy drinkers (119 with alcohol dependence and 88 with alcohol abuse) and 100 control subjects from Castilla y León (Spain). RESULTS: The frequency of G allele carriers was higher in alcohol dependents than in alcohol abusers (47.9% vs 30.6%; p=0.015; OR=2.077; 95% CI 1.165-3.704). CONCLUSION: Our results show that the -93G allele of Fyn kinase gene is associated with higher risk to develop alcohol dependence in Spanish men.
Corredor Z, etal., Sci Rep. 2020 Jan 10;10(1):144. doi: 10.1038/s41598-019-56695-2.
Chronic kidney disease (CKD) patients have many affected physiological pathways. Variations in the genes regulating these pathways might affect the incidence and predisposition to this disease. A total of 722 Spanish adults, including 548 patients and 174 controls, were genotyped to better understan
d the effects of genetic risk loci on the susceptibility to CKD. We analyzed 38 single nucleotide polymorphisms (SNPs) in candidate genes associated with the inflammatory response (interleukins IL-1A, IL-4, IL-6, IL-10, TNF-α, ICAM-1), fibrogenesis (TGFB1), homocysteine synthesis (MTHFR), DNA repair (OGG1, MUTYH, XRCC1, ERCC2, ERCC4), renin-angiotensin-aldosterone system (CYP11B2, AGT), phase-II metabolism (GSTP1, GSTO1, GSTO2), antioxidant capacity (SOD1, SOD2, CAT, GPX1, GPX3, GPX4), and some other genes previously reported to be associated with CKD (GLO1, SLC7A9, SHROOM3, UMOD, VEGFA, MGP, KL). The results showed associations of GPX1, GSTO1, GSTO2, UMOD, and MGP with CKD. Additionally, associations with CKD related pathologies, such as hypertension (GPX4, CYP11B2, ERCC4), cardiovascular disease, diabetes and cancer predisposition (ERCC2) were also observed. Different genes showed association with biochemical parameters characteristic for CKD, such as creatinine (GPX1, GSTO1, GSTO2, KL, MGP), glomerular filtration rate (GPX1, GSTO1, KL, ICAM-1, MGP), hemoglobin (ERCC2, SHROOM3), resistance index erythropoietin (SOD2, VEGFA, MTHFR, KL), albumin (SOD1, GSTO2, ERCC2, SOD2), phosphorus (IL-4, ERCC4 SOD1, GPX4, GPX1), parathyroid hormone (IL-1A, IL-6, SHROOM3, UMOD, ICAM-1), C-reactive protein (SOD2, TGFB1,GSTP1, XRCC1), and ferritin (SOD2, GSTP1, SLC7A9, GPX4). To our knowledge, this is the second comprehensive study carried out in Spanish patients linking genetic polymorphisms and CKD.
Azoulay E, etal., J Appl Physiol (1985). 2003 May;94(5):2027-33. Epub 2003 Jan 10.
Physiopathological discrepancies exist between the most widely used models of pulmonary hypertension (PH), namely monocrotaline- and hypoxia-induced PH. The development of a new model could help in the understanding of underlying mechanisms. Repeated alpha-naphthylthiourea (ANTU) injections (5 mg/kg
weekly, 3 wk) induced pulmonary vascular remodeling, which was associated with development of PH and right ventricular hypertrophy. ANTU followed by granulocyte colony-stimulating factor (G-CSF; 25 microgram. kg(-1). day(-1) subcutaneously, 3 days/wk) induced higher pulmonary arterial pressures and right ventricular hypertrophy than ANTU alone. Lidocaine, which inhibits neutrophil functions, inhibited PH exacerbation by G-CSF. Endothelial nitric oxide synthase expression, measured to assess ANTU-related endothelial toxicity, decreased significantly in ANTU-treated rats and fell even more sharply when G-CSF was given. This occurred despite a significant increase in vascular endothelial cell growth factor expression in lung and right ventricle in rats given ANTU alone and even more in rats given ANTU plus G-CSF. Repeated ANTU administration induces PH with vascular remodeling that can be further aggravated by the neutrophil activator G-CSF.
ABSTRACT: INTRODUCTION: Pandemic A/H1N1/2009 influenza causes severe lower respiratory complications in rare cases. The association between host immune responses and clinical outcome in severe cases is unknown. METHODS: We utilized gene expression, cytokine profiles and generation of antibody respon
ses following hospitalization in 19 critically ill patients with primary pandemic A/H1N1/2009 influenza pneumonia for identifying host immune responses associated with clinical outcome. Ingenuity pathway analysis 8.5 (IPA) (Ingenuity Systems, Redwood City, CA) was used to select, annotate, and visualize genes by function and pathway (gene ontology). IPA analysis identified those canonical pathways differentially expressed (P<0.05) between comparison groups. Hierarchical clustering of those genes differentially expressed between groups by IPA analysis was performed using BRB-Array Tools v.3.8.1. RESULTS: The majority of patients were characterized by the presence of comorbidities and the absence of immunosuppressive conditions. pH1N1 specific antibody production was observed around day 9 from disease onset and defined an early period of innate immune response and a late period of adaptive immune response to the virus. The most severe patients (n=12) showed persistence of viral secretion. Seven of the most severe patients died. During the late phase, the most severe patient group had impaired expression of a number of genes participating in adaptive immune responses when compared to less severe patients. These genes were involved in antigen presentation, B-cell development, T-helper cell differentiation, CD28, granzyme-B signaling, apoptosis and protein ubiquitination. Patients with the poorest outcomes were characterized by pro-inflammatory hypercytokinemia, along with elevated levels of immunosuppresory cytokines (interleukin (IL)-10 and IL-1ra) in serum. CONCLUSIONS: Our findings suggest an impaired development of adaptive immunity in the most severe cases of pandemic influenza, leading to an unremitting cycle of viral replication and innate cytokine-chemokine release. Interruption of this deleterious cycle may improve disease outcome.
We study a patient with the human papilloma virus (HPV)-2-driven "tree-man" phenotype and two relatives with unusually severe HPV4-driven warts. The giant horns form an HPV-2-driven multifocal benign epithelial tumor overexpressing viral oncogenes in the epidermis basal layer. The patients are unexp
ectedly homozygous for a private CD28 variant. They have no detectable CD28 on their T cells, with the exception of a small contingent of revertant memory CD4+ T cells. T cell development is barely affected, and T cells respond to CD3 and CD2, but not CD28, costimulation. Although the patients do not display HPV-2- and HPV-4-reactive CD4+ T cells in vitro, they make antibodies specific for both viruses in vivo. CD28-deficient mice are susceptible to cutaneous infections with the mouse papillomavirus MmuPV1. The control of HPV-2 and HPV-4 in keratinocytes is dependent on the T cell CD28 co-activation pathway. Surprisingly, human CD28-dependent T cell responses are largely redundant for protective immunity.
This study was designed to investigate the role of killer immunoglobulin-like receptor (KIR) genes in the outcome of hepatitis C virus (HCV) infection. In patients who cleared the virus (HCV RNA-) we found a decrease of 2DL2 (P= 0.04), and 2DS2 (P= 0.014) accompanied by an increase of 2DS5 (P= 0.04)
. Those RNA+ patients with elevated levels of hepatic transaminases (HCV RNA+ elevated alanine aminotransferase) showed an increased frequency of 2DS3 (P= 0.018). Additionally, in cirrhotic patients we found an increased frequency of individuals having two copies of 3DS1 and HLA-Bw4 (P= 0.016). We conclude that higher natural killer cytotoxicity might be associated with a worse progression of the HCV infection.
Hartl D, etal., J Immunol. 2008 Dec 1;181(11):8053-67.
Various inflammatory diseases are characterized by tissue infiltration of neutrophils. Chemokines recruit and activate leukocytes, but neutrophils are traditionally known to be restricted in their chemokine receptor (CR) expression repertoire. Neutrophils undergo phenotypic and functional changes un
der inflammatory conditions, but the mechanisms regulating CR expression of infiltrated neutrophils at sites of chronic inflammation are poorly defined. Here we show that infiltrated neutrophils from patients with chronic inflammatory lung diseases and rheumatoid arthritis highly express CR on their surface that are absent or only marginally expressed on circulating neutrophils, i.e., CCR1, CCR2, CCR3, CCR5, CXCR3, and CXCR4, as measured by flow cytometry, immunohistochemistry, and confocal microscopy. The induction of CR surface expression on infiltrated neutrophils was functionally relevant, because receptor activation by chemokine ligands ex vivo modulated neutrophil effector functions such as respiratory burst activity and bacterial killing. In vitro studies with isolated neutrophils demonstrated that the surface expression of CR was differentially induced in a cytokine-mediated, protein synthesis-dependent manner (CCR1, CCR3), through Toll-like (CXCR3) or NOD2 (CCR5) receptor engagement, through neutrophil apoptosis (CCR5, CXCR4), and/or via mobilization of intracellular CD63(+) granules (CXCR3). CR activation on infiltrated neutrophils may represent a key mechanism by which the local inflammatory microenvironment fine-tunes neutrophil effector functions in situ. Since the up-regulation of CR was exclusively found on infiltrated neutrophils at inflammatory sites in situ, the targeting of these G protein-coupled receptors may have the potential to site-specifically target neutrophilic inflammation.
Cervera C, etal., Transplant Proc. 2009 Jul-Aug;41(6):2259-61.
BACKGROUND: Mannose-binding lectin (MBL) is a component of the innate immune system that binds the surface of pathogens, activating the complement pathway and acting as opsonin. Certain single-nucleotide polymorphisms of MBL2 are associated with a decrease in the circulating levels of MBL. Our aim w
as to evaluate the influence of MBL2 polymorphisms in the invasiveness of Cytomegalovirus (CMV) disease after solid organ transplantation. METHODS: We include those solid organ transplant recipients who developed CMV disease posttransplant from 2000 to 2006. MBL2 genotyping was performed by sequencing of exon 1 (wild-type allele A and variants B, C, and D) and promoter regions (alleles H and L, X and Y, and P and Q). In the case of liver transplantation, donor MBL2 genotypes were analyzed. Associations were calculated by the chi-square test and binary logistic regression. RESULTS: We included 45 transplant recipients with CMV disease (22 renal, 7 simultaneous kidney-pancreas, 11 liver, and 5 heart), of whom 10 (22%) had invasive CMV disease. No differences were found regarding HH (versus HL or LL), YY and YX (versus XX) and QQ (versus QP and PP) haplotypes with invasive CMV disease (P = 1.000 for all 3 comparisons). Patients with an exon 1 wild-type (AA) haplotype had 36% invasive CMV disease in comparison with 9% of patients with A/O or O/O haplotypes (P = .035). Binary logistic regression analysis showed that patients with exon 1 AA haplotype had an independent risk of developing invasive CMV disease (odds ratio, 6.0; 95% confidence interval, 1.1-32.5). CONCLUSIONS: Our results suggest that exon 1 wild-type genotypes are associated with a higher risk of invasive CMV disease after solid organ transplantation.
Pingault V, etal., Am J Hum Genet. 2013 May 2;92(5):707-24. doi: 10.1016/j.ajhg.2013.03.024.
Transcription factor SOX10 plays a role in the maintenance of progenitor cell multipotency, lineage specification, and cell differentiation and is a major actor in the development of the neural crest. It has been implicated in Waardenburg syndrome (WS), a rare disorder characterized by the associati
on between pigmentation abnormalities and deafness, but SOX10 mutations cause a variable phenotype that spreads over the initial limits of the syndrome definition. On the basis of recent findings of olfactory-bulb agenesis in WS individuals, we suspected SOX10 was also involved in Kallmann syndrome (KS). KS is defined by the association between anosmia and hypogonadotropic hypogonadism due to incomplete migration of neuroendocrine gonadotropin-releasing hormone (GnRH) cells along the olfactory, vomeronasal, and terminal nerves. Mutations in any of the nine genes identified to date account for only 30% of the KS cases. KS can be either isolated or associated with a variety of other symptoms, including deafness. This study reports SOX10 loss-of-function mutations in approximately one-third of KS individuals with deafness, indicating a substantial involvement in this clinical condition. Study of SOX10-null mutant mice revealed a developmental role of SOX10 in a subpopulation of glial cells called olfactory ensheathing cells. These mice indeed showed an almost complete absence of these cells along the olfactory nerve pathway, as well as defasciculation and misrouting of the nerve fibers, impaired migration of GnRH cells, and disorganization of the olfactory nerve layer of the olfactory bulbs.
Matesanz N, etal., Nat Commun. 2017 Oct 11;8(1):856. doi: 10.1038/s41467-017-00948-z.
Increasing the thermogenic capacity of adipose tissue to enhance organismal energy expenditure is considered a promising therapeutic strategy to combat obesity. Here, we report that expression of the p38 MAPK activator MKK6 is elevated in white adipose tissue of obese individuals. Using knockout ani
mals and shRNA, we show that Mkk6 deletion increases energy expenditure and thermogenic capacity of white adipose tissue, protecting mice against diet-induced obesity and the development of diabetes. Deletion of Mkk6 increases T3-stimulated UC¿P1 expression in adipocytes, thereby increasing their thermogenic capacity. Mechanistically, we demonstrate that, in white adipose tissue, p38 is activated by an alternative pathway involving AMPK, TAK, and TAB. Our results identify MKK6 in adipocytes as a potential therapeutic target to reduce obesity.Brown and beige adipose tissues dissipate heat via uncoupling protein 1 (UCP1). Here the authors show that the stress activated kinase MKK6 acts as a repressor of UCP1 expression, suggesting that its inhibition promotes adipose tissue browning and increases organismal energy expenditure.
Damiola F, etal., Breast Cancer Res Treat. 2015 Dec;154(3):463-71. doi: 10.1007/s10549-015-3625-7. Epub 2015 Nov 12.
Several population-based and family-based studies have demonstrated that germline mutations of the PALB2 gene (Partner and Localizer of BRCA2) are associated with an increased risk of breast cancer. Distinct mutation frequencies and spectrums have been described depending on the population studied.
Here we describe the first complete PALB2 coding sequence screening in the French population. We screened the complete coding sequence and intron-exon boundaries of PALB2, using the EMMA technique, to assess the contribution of pathogenic mutations in a set of 835 familial breast cancer cases and 662 unrelated controls from the French national study GENESIS and the Paul Strauss Cancer Centre, all previously tested negative for BRCA1 and BRCA2 pathogenic mutations. Our analysis revealed the presence of four novel deleterious mutations: c.1186insT, c.1857delT and c.2850delC in three cases, c.3418dupT in one control. In addition, we identified two in-frame insertion/deletion, 19 missense substitutions (two of them predicted as pathogenic), 9 synonymous variants, 28 variants located in introns and 2 in UTRs, as well as frequent variants. Truncating PALB2 mutations were found in 0.36% of familial breast cancer cases, a frequency lower than the one detected in comparable studies in other populations (0.73-3.40%). This suggests a small but significant contribution of PALB2 mutations to the breast cancer susceptibility in the French population.
Confaloni A, etal., Neurosci Lett. 2003 Dec 15;353(1):61-5.
Nicastrin is a protein recently discovered associated to presenilins and involved in the production of amyloid beta peptide that accumulates in Alzheimer's disease (AD) brain. In this study the nicastrin gene was examined for unknown mutations and polymorphisms in 104 patients with familial AD (52 e
arly-onset and 52 late-onset), 174 sporadic AD and 191 healthy neurological controls of Italian origin. The scanning of the nicastrin gene identified a missense mutation (N417Y) in two patients with sporadic AD, in an early-onset familial AD and in a young control subject. Furthermore, we found two silent mutations and four intronic polymorphisms, three of them co-segregating in a single haplotype. We found some differences in the distribution of genotype alterations in the AD population compared to the controls. However, our data together with other evidence did not support the pathological role of missense mutation N417Y.
Cortegano I, etal., Cell Death Differ. 2014 Jul;21(7):1081-94. doi: 10.1038/cdd.2014.27. Epub 2014 Feb 28.
Loss-of-function studies have demonstrated the essential role of Notch in definitive embryonic mouse hematopoiesis. We report here the consequences of Notch gain-of-function in mouse embryo hematopoiesis, achieved by constitutive expression of Notch1 intracellular domain (N1ICD) in angiopoietin rece
ptor tyrosine kinase receptor-2 (Tie2)-derived enhanced green fluorescence protein (EGFP(+)) hematovascular progenitors. At E9.5, N1ICD expression led to the absence of the dorsal aorta hematopoietic clusters and of definitive hematopoiesis. The EGFP(+) transient multipotent progenitors, purified from E9.5 to 10.5 Tie2-Cre;N1ICD yolk sac (YS) cells, had strongly reduced hematopoietic potential, whereas they had increased numbers of hemogenic endothelial cells. Late erythroid cell differentiation stages and mature myeloid cells (Gr1(+), MPO(+)) were also strongly decreased. In contrast, EGFP(+) erythro-myeloid progenitors, immature and intermediate differentiation stages of YS erythroid and myeloid cell lineages, were expanded. Tie2-Cre;N1ICD YS had reduced numbers of CD41(++) megakaryocytes, and these produced reduced below-normal numbers of immature colonies in vitro and their terminal differentiation was blocked. Cells from Tie2-Cre;N1ICD YS had a higher proliferation rate and lower apoptosis than wild-type (WT) YS cells. Quantitative gene expression analysis of FACS-purified EGFP(+) YS progenitors revealed upregulation of Notch1-related genes and alterations in genes involved in hematopoietic differentiation. These results represent the first in vivo evidence of a role for Notch signaling in YS transient definitive hematopoiesis. Our results show that constitutive Notch1 activation in Tie2(+) cells hampers YS hematopoiesis of E9.5 embryos and demonstrate that Notch signaling regulates this process by balancing the proliferation and differentiation dynamics of lineage-restricted intermediate progenitors.
T-box genes regulate development processes, some of these genes having also a role in cell proliferation and survival. TBX15 is a T-box transcription factor that, recently, has been proposed as a marker in prostate cancer, but its function in carcinogenesis is unknown. Here the role of TBX15 in carc
inogenesis was investigated using thyroid cancer cell lines. First, using western blot analysis, we show that the expression of TBX15 was altered in thyroid cancer cells lines with respect to normal thyroid cells. Transfection of thyroid cancer cells with TBX15, in the presence or absence of camptothecin as a cytotoxic agent, proved non effect of TBX15 in cell viability; but, it increased cell proliferation after 48 h of transfection (P < 0.01). Consistently, apoptosis was reduced in TBX15 transfected cells (P < 0.01) which also showed a decrease of the proapoptotic Bax regulator and an increase of the antiapoptotic Bcl2 and Bcl-XL regulators. Additionally, siRNA shutdown of constitutive TBX15 increased apoptosis. TBX15 transfection did not alter colony formation and cell migration. Taken together, these results indicate for the first time an antiapoptotic role of TBX15 in cancer cells, suggesting a contribution of TBX15 in carcinogenesis and the potential therapeutic target of TBX15.
Li S, etal., Breast Cancer Res. 2015 Jul 4;17:91. doi: 10.1186/s13058-015-0590-3.
INTRODUCTION: Chemotherapy remains the only available treatment for triple-negative (TN) breast cancer, and most patients exhibit an incomplete pathologic response. Half of patients exhibiting an incomplete pathologic response die within five years of treatment due to chemo-resistant, recurrent tumo
r growth. Defining molecules responsible for TN breast cancer chemo-resistance is crucial for developing effective combination therapies blocking tumor recurrence. Historically, chemo-resistance studies have relied on long-term chemotherapy selection models that drive genetic mutations conferring cell survival. Other models suggest that tumors are heterogeneous, being composed of both chemo-sensitive and chemo-resistant tumor cell populations. We previously described a short-term chemotherapy treatment model that enriches for chemo-residual TN tumor cells. In the current work, we use this enrichment strategy to identify a novel determinant of TN breast cancer chemotherapy resistance [a nuclear isoform of basic fibroblast growth factor (bFGF)]. METHODS: Studies are conducted using our in vitro model of chemotherapy resistance. Short-term chemotherapy treatment enriches for a chemo-residual TN subpopulation that over time resumes proliferation. By western blotting and real-time polymerase chain reaction, we show that this chemotherapy-enriched tumor cell subpopulation expresses nuclear bFGF. The importance of bFGF for survival of these chemo-residual cells is interrogated using short hairpin knockdown strategies. DNA repair capability is assessed by comet assay. Immunohistochemistry (IHC) is used to determine nuclear bFGF expression in TN breast cancer cases pre- and post- neoadjuvant chemotherapy. RESULTS: TN tumor cells surviving short-term chemotherapy treatment express increased nuclear bFGF. bFGF knockdown reduces the number of chemo-residual TN tumor cells. Adding back a nuclear bFGF construct to bFGF knockdown cells restores their chemo-resistance. Nuclear bFGF-mediated chemo-resistance is associated with increased DNA-dependent protein kinase (DNA-PK) expression and accelerated DNA repair. In fifty-six percent of matched TN breast cancer cases, percent nuclear bFGF-positive tumor cells either increases or remains the same post- neoadjuvant chemotherapy treatment (compared to pre-treatment). These data indicate that in a subset of TN breast cancers, chemotherapy enriches for nuclear bFGF-expressing tumor cells. CONCLUSION: These studies identify nuclear bFGF as a protein in a subset of TN breast cancers that likely contributes to drug resistance following standard chemotherapy treatment.
OBJECTIVE: Carbon monoxide-releasing molecules (CORMs) represent a pharmacological alternative to CO gas inhalation. Here, we questioned whether CORM-3, a well-characterized water-soluble CORM, could prevent and reverse pulmonary hypertension (PH) in chronically hypoxic mice and in smooth muscle pro
moter 22 serotonin transporter mice overexpressing the serotonin transporter in smooth muscle cells (SMCs). APPROACH AND RESULTS: Treatment with CORM-3 (50 mg/kg per day once daily) for 3 weeks prevented PH, right ventricular hypertrophy, and distal pulmonary artery muscularization in mice exposed to chronic hypoxia and partially reversed PH in smooth muscle promoter 22 serotonin transporter mice by reducing Ki67 dividing pulmonary artery SMCs (PA-SMCs). In these models, CORM-3 markedly increased lung p21 mRNA and protein levels and p21-stained PA-SMCs. These effects contrasted with the transient pulmonary vasodilatation and rise in lung cGMP levels induced by a single injection of CORM-3 in mice exposed to acute hypoxia. Studies in cultured rat PA-SMCs revealed that the inhibitory effects of CORM-3 on cell growth were independent of cGMP formation but associated with increased p21 mRNA and protein levels. Protection against PH by CORM-3 required increased lung expression of p21, as indicated by the inability of CORM-3 to prevent chronic hypoxia-induced PH in p21-deficient mice and to alter the growth of PA-SMCs derived from p21-deficient mice. CORM-3-induced p21 overexpression was linked to p53 activation as assessed by the inability of CORM-3 to prevent PH and induce p21 expression in p53-deficient mice and in PA-SMCs derived from p53-deficient mice. CONCLUSIONS: CORM-3 inhibits pulmonary vascular remodeling via p21, which may represent a useful approach for treating PH.
Gonzalez-Teran B, etal., EMBO J. 2016 Mar 1;35(5):536-52. doi: 10.15252/embj.201591857. Epub 2016 Feb 3.
Non-alcoholic fatty liver disease (NAFLD) is a major health problem and the main cause of liver disease in Western countries. Although NAFLD is strongly associated with obesity and insulin resistance, its pathogenesis remains poorly understood. The disease begins with an excessive accumulation of t
riglycerides in the liver, which stimulates an inflammatory response. Alternative p38 mitogen-activated kinases (p38gamma and p38delta) have been shown to contribute to inflammation in different diseases. Here we demonstrate that p38delta is elevated in livers of obese patients with NAFLD and that mice lacking p38gamma/delta in myeloid cells are resistant to diet-induced fatty liver, hepatic triglyceride accumulation and glucose intolerance. This protective effect is due to defective migration of p38gamma/delta-deficient neutrophils to the damaged liver. We further show that neutrophil infiltration in wild-type mice contributes to steatosis development by means of inflammation and liver metabolic changes. Therefore, p38gamma and p38delta in myeloid cells provide a potential target for NAFLD therapy.
BACKGROUND: The origin of congenital or childhood nonimmune isolated atrioventricular (AV) block remains unknown. We hypothesized that this conduction abnormality in the young may be a heritable disease. METHODS AND RESULTS: A multicenter retrospective study (13 French referral centers, from 1980-20
09) included 141 children with AV block diagnosed in utero, at birth, or before 15 years of age without structural heart abnormalities and without maternal antibodies. Parents and matched control subjects were investigated for family history and for ECG screening. In parents, a family history of sudden death or progressive cardiac conduction defect was found in 1.4% and 11.1%, respectively. Screening ECGs from 130 parents (mean age 42.0 +/- 6.8 years, 57 couples) were compared with those of 130 matched healthy control subjects. All parents were asymptomatic and in sinus rhythm, except for 1 with undetected complete AV block. Conduction abnormalities were more frequent in parents than in control subjects, found in 50.8% versus 4.6%, respectively (P<0.001). A long PR interval was found in 18.5% of the parents but never in control subjects (P<0.0001). Complete or incomplete right bundle-branch block was observed in 39.2% of the parents and 1.5% of the control subjects (P<0.0001). Complete or incomplete left bundle-branch block was found in 15.4% of the parents and 3.1% of the control subjects (P<0.0006). Estimated heritability for isolated conduction disturbances was 91% (95% confidence interval, 80%-100%). SCN5A mutation screening identified 2 mutations in 2 patients among 97 children. CONCLUSIONS: ECG screening in parents of children affected by idiopathic AV block revealed a high prevalence of conduction abnormalities. These results support the hypothesis of an inheritable trait in congenital and childhood nonimmune isolated AV block.
Houssaini A, etal., Am J Respir Cell Mol Biol. 2013 May;48(5):568-77. doi: 10.1165/rcmb.2012-0429OC.
Pulmonary artery (PA) smooth muscle cell (SMC) proliferation in pulmonary hypertension (PH) may be linked to dysregulated mammalian target of rapamycin (mTOR) signaling. The mTOR pathway involves two independent complexes, mTORC1 and mTORC2, which phosphorylate S6 kinase (S6K) and serine/threonine k
inase (Akt), respectively, and differ in their sensitivity to rapamycin. Here, we evaluated rapamycin-sensitive mTOR substrates and PA-SMC proliferation in rats with monocrotaline (MCT)-induced PH (MCT-PH). Compared with cells from control rats, cultured PA-SMCs from MCT-PH rats exhibited increased growth responses to platelet-derived growth factor, serotonin (5-hydroxytryptophan), IL-1beta, insulin-like growth factor-1, or fetal calf serum (FCS), with increases in phosphorylated (Ser-473)Akt, (Thr-308)Akt, glycogen synthase kinase (GSK)3, and S6K reflecting activated mTORC1 and mTORC2 signaling. Treatment with rapamycin (0.5 muM) or the Akt inhibitor, A-443654 (0.5 muM), reduced FCS-stimulated growth of PA-SMCs from MCT-PH rats to the level in control rats while inhibiting Akt, GSK3, and S6K activation. Neither the tyrosine kinase inhibitor, imatinib (0.1 muM), nor the 5-hydroxytryptophan transporter inhibitor, fluoxetine (5 muM), normalized the increased PA-SMC growth response to FCS. Rapamycin treatment (5 mg/kg/d) of MCT-PH rats from Day 21 to Day 28 markedly reduced phoshop (p)-Aky, p-GSK3, and p-S6K in PAs, and normalized growth of derived PA-SMCs. This effect was not observed after 1 week of imatinib (100 mg/kg/d) or fluoxetine (20 mg/kg/d). Rapamycin given preventively (Days 1-21) or curatively (Days 21-42) inhibited MCT-PH to a greater extent than did imatinib or fluoxetine. Experimental PH in rats is associated with a sustained proliferative PA-SMC phenotype linked to activation of both mTORC1 and mTORC2 signaling and is suppressed by rapamycin treatment.
Mouraret N, etal., Circulation. 2015 Feb 24;131(8):742-55. doi: 10.1161/CIRCULATIONAHA.114.013258. Epub 2014 Dec 30.
BACKGROUND: Cells exhibiting dysregulated growth may express telomerase reverse transcriptase (TERT), the dual function of which consists of maintaining telomere length, in association with the RNA template molecule TERC, and controlling cell growth. Here, we investigated lung TERT in human and exp
erimental pulmonary hypertension (PH) and its role in controlling pulmonary artery smooth muscle cell (PA-SMC) proliferation. METHODS AND RESULTS: Marked TERT expression or activity was found in lungs from patients with idiopathic PH and from mice with PH induced by hypoxia or serotonin-transporter overexpression (SM22-5HTT(+) mice), chiefly within PA-SMCs. In cultured mouse PA-SMCs, TERT was expressed on growth stimulation by serum. The TERT inhibitor imetelstat and the TERT activator TA65 abrogated and stimulated PA-SMC growth, respectively. PA-SMCs from PH mice showed a heightened proliferative phenotype associated with increased TERT expression, which was suppressed by imetelstat treatment. TERC(-/-) mice at generation 2 and TERT(-/-) mice at generations 2, 3, and 4 developed less severe PH than did wild-type mice exposed to chronic hypoxia, with less distal pulmonary artery muscularization and fewer Ki67-stained proliferating PA-SMCs. Telomere length differed between TERC(-/-) and TERT(-/-) mice, whereas PH severity was similar in the 2 strains and across generations. Chronic imetelstat treatment reduced hypoxia-induced PH in wild-type mice or partially reversed established PH in SM22-5HTT(+) mice while simultaneously decreasing TERT expression. Opposite effects occurred in mice treated with TA65. CONCLUSIONS: Telomerase exerts telomere-independent effects on PA-SMC growth in PH and may constitute a treatment target for PH.
Crotti L, etal., J Am Coll Cardiol. 2012 Oct 9;60(15):1410-8. doi: 10.1016/j.jacc.2012.04.037. Epub 2012 Jul 25.
OBJECTIVES: The aim of this study was to provide the spectrum and prevalence of mutations in the 12 Brugada syndrome (BrS)-susceptibility genes discovered to date in a single large cohort of unrelated BrS patients. BACKGROUND: BrS is a potentially lethal heritable arrhythmia syndrome diagnosed elect
rocardiographically by coved-type ST-segment elevation in the right precordial leads (V1 to V3; type 1 Brugada electrocardiographic [ECG] pattern) and the presence of a personal/family history of cardiac events. METHODS: Using polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing, comprehensive mutational analysis of BrS1- through BrS12-susceptibility genes was performed in 129 unrelated patients with possible/probable BrS (46 with clinically diagnosed BrS [ECG pattern plus personal/family history of a cardiac event] and 83 with a type 1 BrS ECG pattern only). RESULTS: Overall, 27 patients (21%) had a putative pathogenic mutation, absent in 1,400 Caucasian reference alleles, including 21 patients with an SCN5A mutation, 2 with a CACNB2B mutation, and 1 each with a KCNJ8 mutation, a KCND3 mutation, an SCN1Bb mutation, and an HCN4 mutation. The overall mutation yield was 23% in the type 1 BrS ECG pattern-only patients versus 17% in the clinically diagnosed BrS patients and was significantly greater among young men<20 years of age with clinically diagnosed BrS and among patients who had a prolonged PQ interval. CONCLUSIONS: We identified putative pathogenic mutations in approximately 20% of our BrS cohort, with BrS genes 2 through 12 accounting for <5%. Importantly, the yield was similar between patients with only a type 1 BrS ECG pattern and those with clinically established BrS. The yield approaches 40% for SCN5A-mediated BrS (BrS1) when the PQ interval exceeds 200 ms. Calcium channel-mediated BrS is extremely unlikely in the absence of a short QT interval.
Bermejo-Martin JF, etal., Crit Care. 2009;13(6):R201. Epub 2009 Dec 11.
INTRODUCTION: Human host immune response following infection with the new variant of A/H1N1 pandemic influenza virus (nvH1N1) is poorly understood. We utilize here systemic cytokine and antibody levels in evaluating differences in early immune response in both mild and severe patients infected with
nvH1N1. METHODS: We profiled 29 cytokines and chemokines and evaluated the haemagglutination inhibition activity as quantitative and qualitative measurements of host immune responses in serum obtained during the first five days after symptoms onset, in two cohorts of nvH1N1 infected patients. Severe patients required hospitalization (n = 20), due to respiratory insufficiency (10 of them were admitted to the intensive care unit), while mild patients had exclusively flu-like symptoms (n = 15). A group of healthy donors was included as control (n = 15). Differences in levels of mediators between groups were assessed by using the non parametric U-Mann Whitney test. Association between variables was determined by calculating the Spearman correlation coefficient. Viral load was performed in serum by using real-time PCR targeting the neuraminidase gene. RESULTS: Increased levels of innate-immunity mediators (IP-10, MCP-1, MIP-1beta), and the absence of anti-nvH1N1 antibodies, characterized the early response to nvH1N1 infection in both hospitalized and mild patients. High systemic levels of type-II interferon (IFN-gamma) and also of a group of mediators involved in the development of T-helper 17 (IL-8, IL-9, IL-17, IL-6) and T-helper 1 (TNF-alpha, IL-15, IL-12p70) responses were exclusively found in hospitalized patients. IL-15, IL-12p70, IL-6 constituted a hallmark of critical illness in our study. A significant inverse association was found between IL-6, IL-8 and PaO2 in critical patients. CONCLUSIONS: While infection with the nvH1N1 induces a typical innate response in both mild and severe patients, severe disease with respiratory involvement is characterized by early secretion of Th17 and Th1 cytokines usually associated with cell mediated immunity but also commonly linked to the pathogenesis of autoimmune/inflammatory diseases. The exact role of Th1 and Th17 mediators in the evolution of nvH1N1 mild and severe disease merits further investigation as to the detrimental or beneficial role these cytokines play in severe illness.
Microtubule-associated protein tau (MAPT) and apolipoprotein E (APOE) are involved in the pathogenic mechanisms of Alzheimer's disease (AD). We prospectively followed three longitudinal independent samples (total n=319) with amnestic mild cognitive impairment (MCI) and analyzed whether MAPT H1/H2 h
aplotypes and APOE epsilon4 polymorphisms accelerated the rate of progression from MCI to dementia. At the end of the study, 172 subjects remained cognitively stable, whereas 147 progressed to dementia. APOE epsilon4 and MAPT H1/H1 were independently associated with an increased rate of progression to dementia in the combined sample. Cox regression models of the combined MCI sample showed that MAPT H1/H1 carriers had an increased rate of progression to dementia compared with non carriers (Hazard Ratio =1.45; 95% CI=1.04-2.02; p=0.028) and time-to-progression was shortened by 1.37 years. APOE epsilon4 allele also accelerated progression to dementia (Hazard Ratio=1.47; 95% CI= 1.06-2.04; p=0.020) and reduced the time-to-progression by 0.87 years. Additionally, MAPT H1/H1 genotype and APOE epsilon4 allele had an additive effect in progression to dementia, increasing progression rate to dementia (Hazard Ratio=2.24, 95% CI =1.40-3.58; p=0.001) and shortening time-to-progression to dementia by 2.92 years. Similar results were obtained when only considering progression to AD-type dementia. Our results suggest that both MAPT H1/H1 genotype and APOE epsilon4 allele lead to a more rapid progression to dementia among MCI subjects, probably mediating an increased rate of amyloid-beta and tau brain deposition.
Triggering receptor expressed on myeloid (TREM)-1 is integral to the inflammatory response occurring during septic shock, although its precise function has yet to be determined. Here we show that in vivo silencing of TREM-1 using siRNA duplexes in a fecal peritonitis mouse model resulted in a blunte
d inflammatory response and increased mortality. This was associated with impaired bacterial clearance related to marked inhibition of the neutrophil oxidative burst. By contrast, TREM-1-silenced mice were highly resistant to a lethal endotoxin challenge, while partial silencing of TREM-1 in the bacterial peritonitis model produced a significant survival benefit. These data highlight the crucial role of the TREM-1 pathway in mounting an adequate inflammatory and cytotoxic response to polymicrobial sepsis, and both the therapeutic promise and potential risks of its modulation.
Izikki M, etal., Am J Physiol Lung Cell Mol Physiol. 2007 Oct;293(4):L1045-52. Epub 2007 Aug 3.
Serotonin [5-hydroxytryptamine (5-HT)] biosynthesis depends on two rate-limiting tryptophan hydroxylases (Tph): Tph1, which is expressed in peripheral organs, and Tph2, which is expressed in neurons. Because 5-HT is involved in pulmonary hypertension (PH), we investigated whether genetic variations
in Tph1 and/or Tph2 affected PH development in mice. To examine the functional impact of peripheral Tph1 deficiency on hypoxic PH, we used Tph1(-/-) mice characterized by very low 5-HT synthesis rates and contents in the gut and lung and increased 5-HT synthesis in the forebrain. With chronic hypoxia, 5-HT synthesis in the forebrain increased further. Hypoxic PH, right ventricular hypertrophy, and distal pulmonary artery muscularization were less severe (P < 0.001) than in wild-type controls. The Tph inhibitor p-chlorophenylalanine (100 mgxkg(-1)xday(-1)) further improved these parameters. We then investigated whether mouse strains harboring the C1473G polymorphism of the Tph2 gene showed different PH phenotypes during hypoxia. Forebrain Tph activity was greater and hypoxic PH was more severe in C57Bl/6 and 129X1/SvJ mice homozygous for the 1473C allele than in DBA/2 and BALB/cJ mice homozygous for the 1473G allele. p-Chlorophenylalanine reduced PH in all groups and abolished the difference in PH severity across mouse strains. Hypoxia increased 5-hydroxytryptophan accumulation but decreased 5-HT contents in the forebrain and lung, suggesting accelerated 5-HT turnover during hypoxia. These results provide evidence that dysregulation of 5-HT synthesis is closely linked to the hypoxic PH phenotype in mice and that Tph1 and Tph2 may contribute to PH development.
De Stasi AM, etal., Cereb Cortex. 2016 Apr;26(4):1778-94. doi: 10.1093/cercor/bhw002. Epub 2016 Jan 26.
Severe myoclonic epilepsy of infancy (SMEI) is associated with loss of function of the SCN1A gene encoding the NaV1.1 sodium channel isoform. Previous studies in Scn1a(-/+) mice during the pre-epileptic period reported selective reduction in interneuron excitability and proposed this as the main pat
hological mechanism underlying SMEI. Yet, the functional consequences of this interneuronal dysfunction at the circuit level in vivo are unknown. Here, we investigated whether Scn1a(-/+) mice showed alterations in cortical network function. We found that various forms of spontaneous network activity were similar in Scn1a(-/+) during the pre-epileptic period compared with wild-type (WT) in vivo. Importantly, in brain slices from Scn1a(-/+) mice, the excitability of parvalbumin (PV) and somatostatin (SST) interneurons was reduced, epileptiform activity propagated more rapidly, and complex synaptic changes were observed. However, in vivo, optogenetic reduction of firing in PV or SST cells in WT mice modified ongoing network activities, and juxtasomal recordings from identified PV and SST interneurons showed unaffected interneuronal firing during spontaneous cortical dynamics in Scn1a(-/+) compared with WT. These results demonstrate that interneuronal hypoexcitability is not observed in Scn1a(-/+) mice during spontaneous activities in vivo and suggest that additional mechanisms may contribute to homeostatic rearrangements and the pathogenesis of SMEI.
Akdi A, etal., Thyroid. 2010 Jul;20(7):803-9. doi: 10.1089/thy.2010.0072.
BACKGROUND: A member of the genes encoding WD-repeat proteins, the WDR3 gene, maps in the 1p12 region. This region was shown to be associated with thyroid cancer susceptibility in a previous work. In this study we aim to evaluate the contribution of WDR3 to thyroid cancer risk. METHODS: A case-contr
ol association study was performed in a total of 402 patients and 479 control subjects from a Spanish population. In the initial phase of the study, 10 single-nucleotide polymorphisms covering the WDR3 region were genotyped in a small group (157 patients and 118 control subjects); next, three of the initial single-nucleotide polymorphisms were further genotyped in the overall population. In addition, WDR3 expression was investigated in 10 thyroid cancer cell lines by RT-PCR and Western blot. RESULTS: Haplotype analysis revealed that combination of certain WDR3 variants, such as haplotype CAT, increases the risk of thyroid cancer (odds ratio = 1.85, 95% confidence interval = 0.97-3.55, p = 0.063). Further, both messenger RNA transcription and protein expression of WDR3 were altered in human thyroid cancer cells. CONCLUSION: These results indicate for the first time that WDR3 is a risk factor to thyroid cancer, suggesting its implication in the etiology of thyroid cancer.
GLUT1 deficiency (GLUT1D) has recently been identified as an important cause of generalized epilepsies in childhood. As it is a treatable condition, it is crucial to determine which patients should be investigated. METHODS: We analyzed SLC2A1 for mutations in a group of 93 unrelated children with g
eneralized epilepsies. Fasting lumbar puncture was performed following the identification of a mutation. We compared our results with a systematic review of 7 publications of series of patients with generalized epilepsies screened for SLC2A1 mutations. RESULTS: We found 2/93 (2.1%) patients with a SLC2A1 mutation. One, carrying a novel de novo deletion had epilepsy with myoclonic-atonic seizures (MAE), mild slowing of head growth, choreiform movements and developmental delay. The other, with a paternally inherited missense mutation, had childhood absence epilepsy with atypical EEG features and paroxysmal exercise-induced dyskinesia (PED) initially misdiagnosed as myoclonic seizures. Out of a total of 1110 screened patients with generalized epilepsies from 7 studies, 2.4% (29/1110) had GLUT1D. This rate was higher (5.6%) among 303 patients with early onset absence epilepsy (EOAE) from 4 studies. About 50% of GLUT1D patients had abnormal movements and 41% a family history of seizures, abnormal movements or both. CONCLUSION: GLUT1D is most likely to be found in MAE and in EOAE. The probability of finding GLUT1D in the classical idiopathic generalized epilepsies is very low. Pointers to GLUT1D include an increase in seizures before meals, cognitive impairment, or PED which can easily be overlooked.
Intestinal-type sinonasal adenocarcinoma represents 8% to 25% of all malignant sinonasal cancer and is etiologically related to occupational exposure to wood dust. Despite its clear etiology, the mechanisms behind the carcinogenic effects of wood dust are unclear. Because it is known that carcinoge
ns can leave specific mutational fingerprints, we aimed to analyze the spectrum of TP53 mutations and to relate the findings to the wood dust etiology of the patients. Forty-four primary tumors were examined for TP53 mutations by direct sequencing. In addition, p53 protein expression was analyzed by immunohistochemistry using a tissue microarray consisting of 92 tumors. We report a frequency of 41% (18/44) TP53 mutations and 72% (66/92) p53 immunopositivity in intestinal-type sinonasal adenocarcinoma, significantly related to wood dust, but not to tobacco etiology. G-->A transition (50%, 9/18 cases) was the most common alteration detected, almost exclusively found in nonsmokers, whereas G-->T (27%, 5/18 cases) was detected in smokers only. These data point to wood dust exposure as the causal factor in the mutagenesis of TP53, possibly caused by reactive nitrogen species generated through a chronic inflammatory process.
The limb-girdle muscular dystrophies are a genetically heterogeneous group of inherited progressive muscle disorders that affect mainly the proximal musculature, with evidence for at least three autosomal dominant and eight autosomal recessive loci. The latter mostly involve mutations in genes encod
ing components of the dystrophin-associated complex; another form is caused by mutations in the gene for the muscle-specific protease calpain 3. Using a positional cloning approach, we have identified the gene for a form of limb-girdle muscular dystrophy that we previously mapped to chromosome 2p13 (LGMD2B). This gene shows no homology to any known mammalian gene, but its predicted product is related to the C. elegans spermatogenesis factor fer-1. We have identified two homozygous frameshift mutations in this gene, resulting in muscular dystrophy of either proximal or distal onset in nine families. The proposed name 'dysferlin' combines the role of the gene in producing muscular dystrophy with its C. elegans homology.
Nicholl DJ, etal., Neurology. 1999 Oct 22;53(7):1415-21.
OBJECTIVE: To determine whether reported genetic association of polymorphisms in the CYP2D6, CYP1A1, N-acetyltransferase 2 (NAT2), DAT1, and glutathione s-transferase M1 (GSTM1) genes with PD were evident in a population of 176 unrelated patients with sporadic PD and to extend these findings to oth
er disease groups (familial PD [n = 30], ALS [n = 50], multiple system atrophy [n = 38], progressive supranuclear palsy [n = 35], and AD [n = 23]). METHODS: A combination of allele-specific PCR and analysis of restriction fragment length polymorphisms were performed. RESULTS: We genotyped 1,131 individuals. After matching each patient with a control subject by age, sex, ethnicity, and geographic origin, there was no association of any allele/genotype with any of the six disease groups. There was an increased frequency of NAT2 slow acetylators in the ALS group compared with controls (70% versus 50%; OR 2.33 [95% CI, 1.03 to 5.30]), but this was not significant after adjusting for multiple testing. CONCLUSIONS: This is one of the most extensive candidate gene studies performed in PD and the first time that some of these loci have been studied in multiple system atrophy and progressive supranuclear palsy. In contrast with previous studies, we found no role for these polymorphisms in the etiology of PD, ALS, multiple system atrophy, progressive supranuclear palsy, or AD.
In mice, trophoblasts are equipped with a potent anticoagulant mechanism, the protein C pathway. In human placenta, no functional studies of the protein C pathway are available. Human first-trimester trophoblasts (CK(++) HLA-G(+/-) Vim(-)) were isolated and kept in culture for a maximum of 48 hours.
Activation of protein C on trophoblasts was at least as efficient as in endothelial cells (4.43 x 10 (-) (7) nmol/L/min/cell). Endothelial protein C receptor (EPCR) was expressed in syncytiotrophoblasts and extravillous trophoblasts. Downregulation of the messenger RNA of trophoblast EPCR occurred when trophoblasts were challenged with tumor necrosis factor alpha, and it could be prevented by unfractionated heparin but not by low-molecular-weight heparin at therapeutic doses. In conclusion, there is a functional protein C pathway on human first-trimester trophoblasts which can be modulated by inflammation. This finding has implications for the pathogenesis and prevention of placenta-mediated obstetric complications.
Prostate cancer is among the most commonly diagnosed male diseases and a leading cause of cancer mortality in men. There is emerging evidence that autophagy plays an important role in malignant cell survival and offers protection from the anti-cancer drugs in prostate cancer cells. AMBRA1 and the a
utophagic protein sequestosome-1 (SQSTM1; p62) expression were evaluated by immunohistochemistry and western blot on tissue samples from both benign and malignant prostatic lesions. The data reported in this pilot study demonstrated an increased expression of AMBRA1 and SQSTM1, which were also associated with an accumulation of LC3II in prostate cancer but not in benign lesion. In the present study we found that: (i) at variance with benign lesion, prostate cancer cells underwent SQSTM1 accumulation, i.e., clearly displayed a defective autophagic process but, also, (ii) prostate cancer accumulated AMBRA1 and (iii) this increase positively correlated with the Gleason score. These results underscore a possible implication of autophagy in prostate cancer phenotype and of AMBRA1 as possible cancer progression biomarker in this malignancy.
In animals, silicon is an abundant and differentially distributed trace element that is believed to play important biological functions. One would thus expect silicon concentrations in body fluids to be regulated by silicon transporters at the surface of many cell types. Curiously, however, and eve
n though they exist in plants and algae, no such transporters have been identified to date in vertebrates. Here, we show for the first time that the human aquaglyceroporins, i.e., AQP3, AQP7, AQP9 and AQP10 can act as silicon transporters in both Xenopus laevis oocytes and HEK-293 cells. In particular, heterologously expressed AQP7, AQP9 and AQP10 are all able to induce robust, saturable, phloretin-sensitive silicon transport activity in the range that was observed for low silicon rice 1 (lsi1), a silicon transporter in plant. Furthermore, we show that the aquaglyceroporins appear as relevant silicon permeation pathways in both mice and humans based on 1) the kinetics of substrate transport, 2) their presence in tissues where silicon is presumed to play key roles and 3) their transcriptional responses to changes in dietary silicon. Taken together, our data provide new evidence that silicon is a potentially important biological element in animals and that its body distribution is regulated. They should open up original areas of investigations aimed at deciphering the true physiological role of silicon in vertebrates.
BNAR syndrome (MIM608980) is a very rare condition: nine cases belonging to three unrelated families were reported since its first description in 2002. The distinctive clinical feature is the bifidity of the tip of the nose and its association with anorectal and/or renal anomalies. Its molecular bas
is consisting of biallelic FREM1 missense or nonsense mutations was elucidated after studying the original Egyptian family and was confirmed in two families originating from Afghanistan and Pakistan. We describe a fourth family originating from Turkey with signs challenging the diagnostic criteria suggested by the description of the three reported families.
Severini C, etal., Sci Rep. 2015 Oct 19;5:15301. doi: 10.1038/srep15301.
Bv8/Prokineticin 2 (PROK2) is a bioactive peptide initially discovered as a regulator of gastrointestinal motility. Among multiple biological roles demonstrated for PROK2, it was recently established that PROK2 is an insult-inducible endangering mediator for cerebral damage. Aim of the present study
was to evaluate the PROK2 and its receptors' potential involvement in amyloid beta (Abeta) neurotoxicity, a hallmark of Alzheimer's disease (AD) and various forms of traumatic brain injury (TBI). Analyzing primary cortical cultures (CNs) and cortex and hippocampus from Abeta treated rats, we found that PROK2 and its receptors PKR1 and PKR2 mRNA are up-regulated by Abeta, suggesting their potential involvement in AD. Hence we evaluated if impairing the prokineticin system activation might have protective effect against neuronal death induced by Abeta. We found that a PKR antagonist concentration-dependently protects CNs against Abeta(1-42)-induced neurotoxicity, by reducing the Abeta-induced PROK2 neuronal up-regulation. Moreover, the antagonist completely rescued LTP impairment in hippocampal slices from 6 month-old Tg2576 AD mice without affecting basal synaptic transmission and paired pulse-facilitation paradigms. These results indicate that PROK2 plays a role in cerebral amyloidosis and that PROK2 antagonists may represent a new approach for ameliorating the defining pathology of AD.
Chiarini A, etal., Oncol Rep. 2010 Apr;23(4):887-92.
Perylenequinones that generate reactive oxygen species (ROS) when illuminated with visible light have been recommended as photodynamic chemotherapeutic agents. One of these is calphostin C (CalC), the action of the photo-activated derivative of which, CalCphiE, has been ascribed to its ability to se
lectively and irreversibly inhibit protein kinase Cs (PKCs). But recent results of experiments with neoplastic rat fibroblasts and human breast and uterine cervix cancer cells have revealed that the action of CalCphiE involves more than PKC inhibition. Besides suppressing PKC activity, CalCphiE rapidly causes endoplasmic reticulum (ER) stress in breast cancer cells and the selective complete oxidation and proteasomal destruction of the functionally essential nuclear envelope protein lamin B1, in human cervical carcinoma (HCC) cells and neoplastic rat fibroblasts. When these lamin B1-lacking cells are placed in the dark, cytoplasmic membrane-linked PKC activities suddenly rebound and apoptogenesis is initiated as indicated by the immediate release of cytochrome c from mitochondria and later on the activation of caspases. Hence, CalCphiE is a photodynamic cytocidal agent attacking multiple targets in cancer cells and it would be worth determining, even for their best applicative use, whether other perylenequinones also share the so far unexpectedly complex deadly properties of the CalCphiE.
Infectious diseases are frequently observed in children and their recurrence represents a demanding challenge for the paediatrician. It has been hypothesized that a defective immune response may occur in these patients. The aim of the present study was to evaluate whether children presenting with r
ecurrent otitis have a defective interferon (IFN)gamma production by the lymphocytes of peripheral blood and of adenoid tissue, in comparison with children without recurrent otitis. Our study group was represented by 58 children undergoing adenoidectomy for adenoidal hypertrophy. They were subdivided into two groups according to the recurrence of otitis (>or=3 per year) or not (<3 per year). Intracellular cytokine profile of lymphocyte subsets in adenoids and peripheral blood was evaluated by flow cytometry analysis. Children with recurrent otitis showed a significantly lower percentage of CD8+-producing IFN gamma cells in adenoids than children with <3 otitis per year (p = 0.003). The reduced capability of the adenoid cells to produce INF-gamma may induce a high susceptibility to the recurrence of otitis in children.
IGHV3-21-using chronic lymphocytic leukemia (CLL) is a distinct entity with restricted immunoglobulin gene features and poor prognosis and is more frequently encountered in Northern than Southern Europe. To further investigate this subset and its geographic distribution in the context of a country
(Italy) with both continental and Mediterranean areas, 37 IGHV3-21 CLLs were collected out of 1076 cases enrolled by different institutions from Northern or Central Southern Italy. Of the 37 cases, 18 were identified as homologous (hom)HCDR3-IGHV3-21 CLLs and were found almost exclusively (16 of 18) in Northern Italy; in contrast, 19 nonhomHCDR3-IGHV3-21 cases were evenly distributed throughout Italy. Clinically, poor survivals were documented for IGHV3-21 CLLs as well as for subgroups of mutated and homHCDR3-IGHV3-21 CLLs. Negative prognosticators CD38, ZAP-70, CD49d, and CD79b were expressed at higher levels in homHCDR3 than nonhomHCDR3-IGHV3-21 cases. Differential gene expression profiling (GEP) of 13 IGHV3-21 versus 52 non-IGHV3-21 CLLs identified, among 122 best-correlated genes, TGFB2 and VIPR1 as down- and up-regulated in IGHV3-21 CLL cases, respectively. Moreover, GEP of 7 homHCDR3 versus 6 nonhomHCDR3-IGHV3-21 CLLs yielded 20 differentially expressed genes, with WNT-16 being that expressed at the highest levels in homHCDR3-IGHV3-21 CLLs. Altogether, IGHV3-21 CLLs, including those with homHCDR3, had a peculiar global phenotype in part explaining their worse clinical outcome.
FBLN-3 has recently been proposed as a biomarker for malignant mesothelioma. A significantly increased standardized mortality rate from malignant mesothelioma has been reported in Biancavilla, Italy. Its cause has been identified in environmental exposure to fluoro-edenite. The aim of this study was
to seek a correlation between plasma FBLN-3 concentration and pleural plaques in subjects exposed to fluoro-edenite and in a nonexposed control group. Pleural plaques was never detected in the control group, whereas it was found in 52% of exposed subjects. Median FBLN-3 concentrations were 12.96 and 5.29 ng/ml in the exposed and the control group, respectively (p < 0.001). FBLN-3 plasma levels exhibited a high predictive value for the presence of pleural plaques.
De Fusco M, etal., Nat Genet 2003 Feb;33(2):192-6.
Headache attacks and autonomic dysfunctions characterize migraine, a very common, disabling disorder with a prevalence of 12% in the general population of Western countries. About 20% of individuals affected with migraine experience aura, a visual or sensory-motor neurological dysfunction that usual
ly precedes or accompanies the headache. Although the mode of transmission is controversial, population-based and twin studies have implicated genetic factors, especially in migraine with aura. Familial hemiplegic migraine is a hereditary form of migraine characterized by aura and some hemiparesis. Here we show that mutations in the gene ATP1A2 that encodes the alpha2 subunit of the Na+/K+ pump are associated with familial hemiplegic migraine type 2 (FHM2) linked to chromosome 1q23 (OMIM 602481). Functional data indicate that the putative pathogenetic mechanism is triggered by a loss of function of a single allele of ATP1A2. This is the first report associating mutations of Na+K+ pump subunits to genetic diseases.
Paradiso B, etal., Proc Natl Acad Sci U S A. 2009 Apr 28;106(17):7191-6. Epub 2009 Apr 6.
A loss of neurons is observed in the hippocampus of many patients with epilepsies of temporal lobe origin. It has been hypothesized that damage limitation or repair, for example using neurotrophic factors (NTFs), may prevent the transformation of a normal tissue into epileptic (epileptogenesis). Her
e, we used viral vectors to locally supplement two NTFs, fibroblast growth factor-2 (FGF-2) and brain-derived neurotrophic factor (BDNF), when epileptogenic damage was already in place. These vectors were first characterized in vitro, where they increased proliferation of neural progenitors and favored their differentiation into neurons, and they were then tested in a model of status epilepticus-induced neurodegeneration and epileptogenesis. When injected in a lesioned hippocampus, FGF-2/BDNF expressing vectors increased neuronogenesis, embanked neuronal damage, and reduced epileptogenesis. It is concluded that reduction of damage reduces epileptogenesis and that supplementing specific NTFs in lesion areas represents a new approach to the therapy of neuronal damage and of its consequences.
Until recently, thrombocytopenia 2 (THC2) was considered an exceedingly rare form of autosomal dominant thrombocytopenia and only 2 families were known. However, we recently identified mutations in the 5'-untranslated region of the ANKRD26 gene in 9 THC2 families. Here we report on 12 additional ped
igrees with ANKRD26 mutations, 6 of which are new. Because THC2 affected 21 of the 210 families in our database, it has to be considered one of the less rare forms of inherited thrombocytopenia. Analysis of all 21 families with ANKRD26 mutations identified to date revealed that thrombocytopenia and bleeding tendency were usually mild. Nearly all patients had no platelet macrocytosis, and this characteristic distinguishes THC2 from most other forms of inherited thrombocytopenia. In the majority of cases, platelets were deficient in glycoprotein Ia and alpha-granules, whereas in vitro platelet aggregation was normal. Bone marrow examination and serum thrombopoietin levels suggested that thrombocytopenia was derived from dysmegakaryopoiesis. Unexplained high values of hemoglobin and leukocytes were observed in a few cases. An unexpected finding that warrants further investigation was a high incidence of acute leukemia. Given the scarcity of distinctive characteristics, the ANKRD26-related thrombocytopenia has to be taken into consideration in the differential diagnosis of isolated thrombocytopenias.
Pippucci T, etal., Am J Hum Genet. 2011 Jan 7;88(1):115-20. doi: 10.1016/j.ajhg.2010.12.006.
THC2, an autosomal-dominant thrombocytopenia described so far in only two families, has been ascribed to mutations in MASTL or ACBD5. Here, we show that ANKRD26, another gene within the THC2 locus, and neither MASTL nor ACBD5, is mutated in eight unrelated families. ANKRD26 was also found to be muta
ted in the family previously reported to have an ACBD5 mutation. We identified six different ANKRD26 mutations, which were clustered in a highly conserved 19 bp sequence located in the 5' untranslated region. Mutations were not detected in 500 controls and are absent from the 1000 Genomes database. Available data from an animal model and Dr. Watson's genome give evidence against haploinsufficiency as the pathogenetic mechanism for ANKRD26-mediated thrombocytopenia. The luciferase reporter assay suggests that these 5' UTR mutations might enhance ANKRD26 expression. ANKRD26 is the ancestor of a family of primate-specific genes termed POTE, which have been recently identified as a family of proapoptotic proteins. Dysregulation of apoptosis might therefore be the pathogenetic mechanism, as demonstrated for another thrombocytopenia, THC4. Further investigation is needed to provide evidence supporting this hypothesis.
Ferrari S, etal., Proc Natl Acad Sci U S A. 2001 Oct 23;98(22):12614-9.
CD40 is a member of the tumor necrosis factor receptor superfamily, expressed on a wide range of cell types including B cells, macrophages, and dendritic cells. CD40 is the receptor for CD40 ligand (CD40L), a molecule predominantly expressed by activated CD4(+) T cells. CD40/CD40L interaction induce
s the formation of memory B lymphocytes and promotes Ig isotype switching, as demonstrated in mice knocked-out for either CD40L or CD40 gene, and in patients with X-linked hyper IgM syndrome, a disease caused by CD40L/TNFSF5 gene mutations. In the present study, we have identified three patients with an autosomal recessive form of hyper IgM who fail to express CD40 on the cell surface. Sequence analysis of CD40 genomic DNA showed that one patient carried a homozygous silent mutation at the fifth base pair position of exon 5, involving an exonic splicing enhancer and leading to exon skipping and premature termination; the other two patients showed a homozygous point mutation in exon 3, resulting in a cysteine to arginine substitution. These findings show that mutations of the CD40 gene cause an autosomal recessive form of hyper IgM, which is immunologically and clinically undistinguishable from the X-linked form.
Palazzo E, etal., Int J Mol Sci. 2015 Nov 3;16(11):26291-302. doi: 10.3390/ijms161125948.
The Notch signaling pathway orchestrates cell fate by either inducing cell differentiation or maintaining cells in an undifferentiated state. This study aims to evaluate Notch expression and function in normal human keratinocytes. Notch1 is expressed in all epidermal layers, though to a different de
gree of intensity, with a dramatic decrease during ageing. Notch1 intracellular domain (N1ICD) levels are decreased during transit from keratinocyte stem cells (KSC) to transit amplifying (TA) cells, mimicking survivin expression in samples from donors of all ages. Calcium markedly reduces N1ICD levels in keratinocytes. N1ICD overexpression induces the up-regulation of survivin and the down-regulation of keratin 10 and involucrin, while increasing the S phase of the cell cycle. On the other hand, Notch1 inhibition (DAPT) dose-dependently decreases survivin, stimulates differentiation, and reduces keratinocyte proliferation in samples from donors of all ages. Silencing Notch downgrades survivin and increases keratin 10. In addition, Notch1 inhibition decreases survivin levels and proliferation both in KSC and TA cells. Finally, while survivin overexpression decreases keratinocyte differentiation and increases N1ICD expression both in KSC and TA cells, silencing survivin results in N1ICD down-regulation and an increase in differentiation markers. These results suggest that the Notch1/survivin crosstalk contributes to the maintenance of stemness in human keratinocytes.
De Falco F, etal., Oncotarget. 2015 Jun 30;6(18):16559-72.
In chronic lymphocytic leukemia (CLL), Notch1 and Notch2 signaling is constitutively activated and contributes to apoptosis resistance. We show that genetic inhibition of either Notch1 or Notch2, through small-interfering RNA, increases apoptosis of CLL cells and is associated with decreased levels
of the anti-apoptotic protein Mcl-1. Thus, Notch signaling promotes CLL cell survival at least in part by sustaining Mcl-1 expression. In CLL cells, an enhanced Notch activation also contributes to the increase in Mcl-1 expression and cell survival induced by IL-4.Mcl-1 downregulation by Notch targeting is not due to reduced transcription or degradation by caspases, but in part, to increased degradation by the proteasome. Mcl-1 downregulation by Notch targeting is also accompanied by reduced phosphorylation of eukaryotic translation initiation factor 4E (eIF4E), suggesting that this protein is another target of Notch signaling in CLL cells.Overall, we show that Notch signaling sustains CLL cell survival by promoting Mcl-1 expression and eIF4E activity, and given the oncogenic role of these factors, we underscore the therapeutic potential of Notch inhibition in CLL.
Mutations in progranulin gene (GRN) are the most common cause of autosomal dominant familial frontotemporal lobar degeneration (FTLD). In addition, GRN variability influences the risk to develop the disease in non-carriers (sporadic FTLD). We evaluated progranulin gene (GRN) promoter methylation le
vels in peripheral blood mononuclear cells isolated from 38 patients with sporadic FTLD compared with 38 controls, and correlate them with GRN mRNA expression rate. The percentage of methylation of the GRN promoter was increased in patients with FTLD compared with controls (61.5 vs. 46.3 %, P < 0.001). A trend towards decreased GRN relative expression was observed in patients compared with controls (threefold decrease over controls, P > 0.05), together with a negative correlation between the degree of GRN promoter methylation and mRNA GRN levels (rho = -0.1, P > 0.05). GRN promoter methylation was not correlated with age. In conclusion, the degree of methylation of the GRN promoter is increased in patients with FTLD as compared with controls, likely leading to a decreased expression of GRN.
Mangione PP, etal., Proc Natl Acad Sci U S A. 2014 Jan 28;111(4):1539-44. doi: 10.1073/pnas.1317488111. Epub 2014 Jan 13.
The Ser52Pro variant of transthyretin (TTR) produces aggressive, highly penetrant, autosomal-dominant systemic amyloidosis in persons heterozygous for the causative mutation. Together with a minor quantity of full-length wild-type and variant TTR, the main component of the ex vivo fibrils was the re
sidue 49-127 fragment of the TTR variant, the portion of the TTR sequence that previously has been reported to be the principal constituent of type A, cardiac amyloid fibrils formed from wild-type TTR and other TTR variants [Bergstrom J, et al. (2005) J Pathol 206(2):224-232]. This specific truncation of Ser52Pro TTR was generated readily in vitro by limited proteolysis. In physiological conditions and under agitation the residue 49-127 proteolytic fragment rapidly and completely self-aggregates into typical amyloid fibrils. The remarkable susceptibility to such cleavage is likely caused by localized destabilization of the beta-turn linking strands C and D caused by loss of the wild-type hydrogen-bonding network between the side chains of residues Ser52, Glu54, Ser50, and a water molecule, as revealed by the high-resolution crystallographic structure of Ser52Pro TTR. We thus provide a structural basis for the recently hypothesized, crucial pathogenic role of proteolytic cleavage in TTR amyloid fibrillogenesis. Binding of the natural ligands thyroxine or retinol-binding protein (RBP) by Ser52Pro variant TTR stabilizes the native tetrameric assembly, but neither protected the variant from proteolysis. However, binding of RBP, but not thyroxine, inhibited subsequent fibrillogenesis.
Zuffa E, etal., Oncotarget. 2015 Oct 13;6(31):31284-94. doi: 10.18632/oncotarget.5161.
FLT3 internal tandem duplication (ITD), one of the most frequent mutations in Acute Myeloid Leukemia (AML), is reported to be an unstable marker, as it can evolve from FLT3 ITD- to ITD+ during the disease course. A single-gene sensitive mutational screening approach may be helpful for better clarif
ying the exact timing of mutation occurrence, especially when FLT3 ITD appears to occur late, at disease progression. We developed an amplicon-based ultra-deep-sequencing (UDS) approach for FLT3 mutational screening. We exploited this highly sensitive technology for the retrospective screening of diagnosis, relapse and follow-up samples of 5 out of 256 cytogenetically normal (CN-) AML who were FLT3 wild-type at presentation, but tested ITD+ at relapse or disease progression. Our study revealed that all patients carried a small ITD+ clone at diagnosis, which was undetectable by routine analysis (0,2-2% abundance). The dynamics of ITD+ clones from diagnosis to disease progression, assessed by UDS, reflected clonal evolution under treatment pressure. UDS appears as a valuable tool for FLT3 mutational screening and for the assessment of minimal residual disease (MRD) during follow-up, by detecting small ITD+ clones that may survive chemotherapy, evolve over time and definitely worsen the prognosis of CN-AML patients.
Lotti R, etal., Int J Mol Sci. 2016 Jan 12;17(1). pii: E89. doi: 10.3390/ijms17010089.
Squamous Cell Carcinoma-derived Stem-like Cells (SCC-SC) originate from alterations in keratinocyte stem cells (KSC) gene expression and sustain tumor development, invasion and recurrence. Since survivin, a KSC marker, is highly expressed in SCC-SC, we evaluate its role in SCC-SC cell growth and SCC
models. Survivin silencing by siRNA decreases clonal growth of SCC keratinocytes and viability of total, rapidly adhering (RAD) and non-RAD (NRAD) cells from primary SCC. Similarly, survivin silencing reduces the expression of stem cell markers (OCT4, NOTCH1, CD133, beta(1)-integrin), while it increases the level of differentiation markers (K10, involucrin). Moreover, survivin silencing improves the malignant phenotype of SCC 3D-reconstruct, as demonstrated by reduced epidermal thickness, lower Ki-67 positive cell number, and decreased expression of MMP9 and psoriasin. Furthermore, survivin depletion by siRNA in Ras(G12V)-IkappaBalpha-derived tumors leads to smaller tumor formation characterized by lower mitotic index and reduced expression of the tumor-associated marker HIF1alpha, VEGF and CD51. Therefore, our results indicate survivin as a key gene in regulating SCC cancer stem cell formation and cSCC development.
The presence of autoantibodies in multiple sclerosis (MuS) is well known, but their target antigens have not been clearly identified. In the present study, IgG autoreactivity to neural antigens of normal human white matter separated by bidimensional electrophoresis was assessed in serum and cerebros
pinal fluid of 18 MuS and 20 control patients. Broad IgG autoreactivity was detected by two-dimensional immunoblotting in all cases to neural antigens, most of which were identified by mass spectrometry. The comparative analysis of MuS and non-MuS reactive spots showed that a restricted number of neural protein isoforms were specifically recognized by MuS IgG. Almost all MuS patients had cerebrospinal fluid IgG directed to isoforms of one of the oligodendroglial molecules, transketolase, 2',3'-cyclic-nucleotide 3'-phosphodiesterase type I, collapsin response mediator protein 2, and tubulin beta 4. Interestingly 50% of MuS IgG recognized transketolase, which was mostly localized on oligodendrocytes in human white matter from normal and MuS samples. IgG autoreactivity to cytoskeletal proteins (radixin, sirtuin 2, and actin-interacting protein 1) was prevalent in secondary progressive MuS patients. Among the proteins recognized by serum IgG, almost all MuS patients specifically recognized a restricted number of neuronal/cytoskeletal proteins, whereas 2',3'-cyclic-nucleotide 3'-phosphodiesterase type I was the oligodendroglial antigen most frequently recognized (44%) by MuS seric IgG. Our immunomics approach shed new light on the autoimmune repertoire present in MuS patients revealing novel oligodendroglial and/or neuronal putative autoantigens with potential important pathogenic and diagnostic implications.
Calì E, etal., Genet Med. 2022 Oct;24(10):2194-2203. doi: 10.1016/j.gim.2022.07.013. Epub 2022 Aug 24.
PURPOSE: The mediator (MED) multisubunit-complex modulates the activity of the transcriptional machinery, and genetic defects in different MED subunits (17, 20, 27) have been implicated in neurologic diseases. In this study, we identified a recurrent homozygous variant in MED11 (c.325C>T;
p.Arg109Ter) in 7 affected individuals from 5 unrelated families. METHODS: To investigate the genetic cause of the disease, exome or genome sequencing were performed in 5 unrelated families identified via different research networks and Matchmaker Exchange. Deep clinical and brain imaging evaluations were performed by clinical pediatric neurologists and neuroradiologists. The functional effect of the candidate variant on both MED11 RNA and protein was assessed using reverse transcriptase polymerase chain reaction and western blotting using fibroblast cell lines derived from 1 affected individual and controls and through computational approaches. Knockouts in zebrafish were generated using clustered regularly interspaced short palindromic repeats/Cas9. RESULTS: The disease was characterized by microcephaly, profound neurodevelopmental impairment, exaggerated startle response, myoclonic seizures, progressive widespread neurodegeneration, and premature death. Functional studies on patient-derived fibroblasts did not show a loss of protein function but rather disruption of the C-terminal of MED11, likely impairing binding to other MED subunits. A zebrafish knockout model recapitulates key clinical phenotypes. CONCLUSION: Loss of the C-terminal of MED subunit 11 may affect its binding efficiency to other MED subunits, thus implicating the MED-complex stability in brain development and neurodegeneration.
The role of the obesity cytokine leptin in breast cancer progression has raised interest in interfering with leptin's actions as a valuable therapeutic strategy. Leptin interacts with its receptor through three different binding sites: I-III. Site I is crucial for the formation of an active leptin-
leptin receptor complex and in its subsequent activation. Amino acids 39-42 (Leu-Asp-Phe-Ile- LDFI) were shown to contribute to leptin binding site I and their mutations in alanine resulted in muteins acting as typical antagonists. We synthesized a small peptide based on the wild-type sequence of leptin binding site I (LDFI) and evaluated its efficacy in antagonizing leptin actions in breast cancer using in vitro and in vivo experimental models. The peptide LDFI abolished the leptin-induced anchorage-dependent and -independent growth as well as the migration of ERalpha-positive (MCF-7) and -negative (SKBR3) breast cancer cells. These results were well correlated with a reduction in the phosphorylation levels of leptin downstream effectors, as JAK2/STAT3/AKT/MAPK. Importantly, the peptide LDFI reversed the leptin-mediated up-regulation of its gene expression, as an additional mechanism able to enhance the peptide antagonistic activity. The described effects were specific for leptin signalling, since the developed peptide was not able to antagonize the other growth factors' actions on signalling activation, proliferation and migration. Finally, we showed that the LDFI pegylated peptide markedly reduced breast tumour growth in xenograft models. The unmodified peptide LDFI acting as a full leptin antagonist could become an attractive option for breast cancer treatment, especially in obese women.
Stewart K, etal., PLoS Genet. 2016 Feb 9;12(2):e1005785. doi: 10.1371/journal.pgen.1005785. eCollection 2016 Feb.
Rho family GTPases act as molecular switches regulating actin cytoskeleton dynamics. Attenuation of their signaling capacity is provided by GTPase-activating proteins (GAPs), including p190A, that promote the intrinsic GTPase activity of Rho proteins. In the current study we have performed a small-s
cale ENU mutagenesis screen and identified a novel loss of function allele of the p190A gene Arhgap35, which introduces a Leu1396 to Gln substitution in the GAP domain. This results in decreased GAP activity for the prototypical Rho-family members, RhoA and Rac1, likely due to disrupted ordering of the Rho binding surface. Consequently, Arhgap35-deficient animals exhibit hypoplastic and glomerulocystic kidneys. Investigation into the cystic phenotype shows that p190A is required for appropriate primary cilium formation in renal nephrons. P190A specifically localizes to the base of the cilia to permit axoneme elongation, which requires a functional GAP domain. Pharmacological manipulations further reveal that inhibition of either Rho kinase (ROCK) or F-actin polymerization is able to rescue the ciliogenesis defects observed upon loss of p190A activity. We propose a model in which p190A acts as a modulator of Rho GTPases in a localized area around the cilia to permit the dynamic actin rearrangement required for cilia elongation. Together, our results establish an unexpected link between Rho GTPase regulation, ciliogenesis and glomerulocystic kidney disease.
miR-96 is a microRNA, a non-coding RNA gene which regulates a wide array of downstream genes. The miR-96 mouse mutant diminuendo exhibits deafness and arrested hair cell functional and morphological differentiation. We have previously shown that several genes are markedly downregulated in the diminu
endo organ of Corti; one of these is Ptprq, a gene known to be important for maturation and maintenance of hair cells. In order to study the contribution that downregulation of Ptprq makes to the diminuendo phenotype, we carried out microarrays, scanning electron microscopy and single hair cell electrophysiology to compare diminuendo mutants (heterozygous and homozygous) with mice homozygous for a functional null allele of Ptprq. In terms of both morphology and electrophysiology, the auditory phenotype of mice lacking Ptprq resembles that of diminuendo heterozygotes, while diminuendo homozygotes are more severely affected. A comparison of transcriptomes indicates there is a broad similarity between diminuendo homozygotes and Ptprq-null mice. The reduction in Ptprq observed in diminuendo mice appears to be a major contributor to the morphological, transcriptional and electrophysiological phenotype, but does not account for the complete diminuendo phenotype.
Carrott L, etal., J Neurosci. 2016 Jan 6;36(1):222-34. doi: 10.1523/JNEUROSCI.1808-15.2016.
The Neuroplastin gene encodes two synapse-enriched protein isoforms, Np55 and Np65, which are transmembrane glycoproteins that regulate several cellular processes, including the genesis, maintenance, and plasticity of synapses. We found that an absence of Np65 causes early-onset sensorineural hearin
g loss and prevented the normal synaptogenesis in inner hair cells (IHCs) in the newly identified mouse mutant pitch. In wild-type mice, Np65 is strongly upregulated in the cochlea from around postnatal day 12 (P12), which corresponds to the onset of hearing. Np65 was specifically localized at the presynaptic region of IHCs. We found that the colocalization of presynaptic IHC ribbons and postsynaptic afferent terminals is greatly reduced in pitch mutants. Moreover, IHC exocytosis is also reduced with mutant mice showing lower rates of vesicle release. Np65 appears to have a nonessential role in vision. We propose that Np65, by regulating IHC synaptogenesis, is critical for auditory function in mammals. SIGNIFICANCE STATEMENT: In the mammalian cochlea, the sensory inner hair cells (IHCs) encode auditory information. They do this by converting sound wave-induced mechanical motion of their hair bundles into an electrical current. This current generates a receptor potential that controls release of glutamate neurotransmitter from their ribbon synapses onto the auditory afferent fiber. We show that the synapse-enriched protein Np65, encoded by the Neuroplastin gene, is localized at the IHC presynaptic region. In mutant mice, absence of Np65 causes early-onset sensorineural hearing loss and prevents normal neurotransmitter release in IHCs and colocalization of presynaptic ribbons with postsynaptic afferents. We identified Neuroplastin as a novel deafness gene required for ribbon synapse formation and function, which is critical for sound perception in mammals.
Grabner A, etal., Cell Metab. 2015 Dec 1;22(6):1020-32. doi: 10.1016/j.cmet.2015.09.002. Epub 2015 Oct 1.
Chronic kidney disease (CKD) is a worldwide public health threat that increases risk of death due to cardiovascular complications, including left ventricular hypertrophy (LVH). Novel therapeutic targets are needed to design treatments to alleviate the cardiovascular burden of CKD. Previously, we dem
onstrated that circulating concentrations of fibroblast growth factor (FGF) 23 rise progressively in CKD and induce LVH through an unknown FGF receptor (FGFR)-dependent mechanism. Here, we report that FGF23 exclusively activates FGFR4 on cardiac myocytes to stimulate phospholipase Cgamma/calcineurin/nuclear factor of activated T cell signaling. A specific FGFR4-blocking antibody inhibits FGF23-induced hypertrophy of isolated cardiac myocytes and attenuates LVH in rats with CKD. Mice lacking FGFR4 do not develop LVH in response to elevated FGF23, whereas knockin mice carrying an FGFR4 gain-of-function mutation spontaneously develop LVH. Thus, FGF23 promotes LVH by activating FGFR4, thereby establishing FGFR4 as a pharmacological target for reducing cardiovascular risk in CKD.
Dillon RL, etal., Cancer Res. 2009 Jun 15;69(12):5057-64. Epub 2009 Jun 2.
The phosphatidylinositol 3-kinase (PI3K)/Akt survival pathway is often dysregulated in cancer. Our previous studies have shown that coexpression of activated Akt1 with activated ErbB2 or polyoma virus middle T antigen uncoupled from the PI3K pathway (PyVmT Y315/322F) accelerates mammary tumor develo
pment but cannot rescue the metastatic phenotype associated with these models. Here, we report the generation of transgenic mice expressing activated Akt2 in the mammary epithelium. Like the mouse mammary tumor virus-Akt1 strain, mammary-specific expression of Akt2 delayed mammary gland involution. However, in contrast to Akt1, coexpression of Akt2 with activated ErbB2 or PyVmT Y315/322F in the mammary glands of transgenic mice did not affect the latency of tumor development. Strikingly, Akt2 coexpresssion markedly increased the incidence of pulmonary metastases in both tumor models, demonstrating a unique role in tumor progression. Together, these observations argue that these highly conserved kinases have distinct biological and biochemical outputs that play opposing roles in mammary tumor induction and metastasis.
The hotspot AKT1E17K mutation in the pleckstrin homology domain of AKT1 occurs in approximately 0.6-2% of human lung cancers. Recently, we have demonstrated that AKT1E17K transforms immortalized human bronchial cells. Here by use of a transgenic Cre-inducible murine strain in the wild type Rosa26 (R
26) locus (R26-AKT1E17K mice) we demonstrate that AKT1E17K is a bona-fide oncogene and plays a role in the development of lung cancer in vivo. In fact, we report that mutant AKT1E17K induces bronchial and/or bronchiolar hyperplastic lesions in murine lung epithelium, which progress to frank carcinoma at very low frequency, and accelerates tumor formation induced by chemical carcinogens. In conclusion, AKT1E17K induces hyperplasia of mouse lung epithelium in vivo and cooperates with urethane to induce the fully malignant phenotype.
Alport syndrome (ATS) is a nephropathy characterized by the association of progressive hematuric nephritis with ultrastructural changes of the glomerular basement membrane (thinning, thickening, and splitting), sensorineural deafness, and variable ocular abnormalities (anterior lenticonus, macular
flecks, and cataracts). The most common mode of transmission is X-linked inheritance, due to COL4A5 mutations. X-linked ATS is rarely associated with diffuse leiomyomatosis (DL), a benign hypertrophy of the visceral smooth muscle in gastrointestinal, respiratory, and female reproductive tracts. The ATS-DL complex is due to deletions that encompass the 5' ends of the COL4A5 and COL4A6 genes and include the bidirectional promoter. In this paper, we described 3 ATS-DL cases, 2 familial and 1 sporadic bearing a deletion encompassing the 5'-end of both the COL4A5 and COL4A6 genes, as identified by multiplex ligation-dependent probe amplification (MLPA) analysis. The array-CGH technique allowed a better definition of deletion size, confirming that the proximal breakpoint was within COL4A6 intron 2 in 2 cases. Surprisingly, 1 case had a deletion extending proximally beyond exon 3 of COL4A6, as confirmed by qPCR analysis. This is the largest deletion reported to date that has been associated with ATS-DL and this case should lead us to reconsider the mechanisms that might be involved in the development of diffuse leiomyomatosis.
Different genes are associated with categorical classifications of asthma severity. However, continuous outcomes should be used to catch the heterogeneity of asthma phenotypes and to increase the power in association studies. Accordingly, the aim of this study was to evaluate the association betwee
n single nucleotide polymorphisms (SNPs) in candidate gene regions and continuous measures of asthma severity, in adult patients from the general population. In the Gene Environment Interactions in Respiratory Diseases (GEIRD) study (www.geird.org), 326 subjects (aged 20-64) with ever asthma were identified from the general population in Verona (Italy) between 2007 and 2010. A panel of 236 SNPs tagging 51 candidate gene regions (including one or more genes) was analysed. A symptom and treatment score (STS) and pre-bronchodilator FEV1% predicted were used as continuous measures of asthma severity. The association of each SNP with STS and FEV1% predicted was tested by fitting quasi-gamma and linear regression models, respectively, with gender, body mass index and smoking habits as potential confounders. The Simes multiple-test procedure was used for controlling the false discovery rate (FDR). SNP rs848 in the IL13 gene region (IL5/RAD50/IL13/IL4) was associated with STS (TG/GG vs TT genotype: uncorrected p-value = 0.00006, FDR-corrected p-value = 0.04), whereas rs20541 in the same gene region, in linkage disequilibrium with rs848 (r(2) = 0.94) in our sample, did not reach the statistical significance after adjusting for multiple testing (TC/CC vs TT: uncorrected p-value = 0.0003, FDR-corrected p-value = 0.09). Polymorphisms in other gene regions showed a non-significant moderate association with STS (IL12B, TNS1) or lung function (SERPINE2, GATA3, IL5, NPNT, FAM13A) only. After adjusting for multiple testing and potential confounders, SNP rs848 in the IL13 gene region is significantly associated with a continuous measure of symptom severity in adult subjects with ever asthma.
BACKGROUND: A recent study in German and Italian families associated variants in the interleukin-1 receptor antagonist (IL1RA) gene with asthma. The aim of the present study was to further investigate the role of single nucleotide polymorphisms (SNPs) in the IL1RA gene in the development of atopy an
d lifelong asthma in a population-based study. METHODS: DNA samples from the German centres of the European Community Respiratory Health Survey were analysed for genetic variants in the IL1RA gene and the development of asthma, atopy and bronchial hyperreactivity. RESULTS: Carriers of the rare G allele of SNP rs447713 had a significantly increased risk of developing asthma (P = 0.0013) and allergic sensitization (P = 0.0119). Carriers of the rare C allele of SNP rs3087271 had an increased risk of asthma (P = 0.0227) and high immunoglobulin E (IgE) levels (P = 0.0232). A haplotype built from eight SNPs in the IL1RA gene (A-C-A-G-A-C-G-A) was associated with a higher prevalence of asthma (P = 0.007) and high total IgE (P = 0.02). Bronchial hyperreactivity was positively associated with the haplotype A-C-G-G-A-C-G-C (P = 0.02) and negatively with the A-C-G-G-A-C-T-C (P = 0.03). CONCLUSION: A previously described association between IL1RA and asthma in families could be reproduced in a population-based sample. The genetic variants of IL1RA gene do not to seem to affect asthma alone, but to act as modulators of asthma-related traits as well, where different haplotypes drive the development of different phenotypes.
Meloni A, etal., J Clin Endocrinol Metab. 2008 Nov;93(11):4389-97. doi: 10.1210/jc.2008-0935. Epub 2008 Aug 26.
CONTEXT: In autoimmune polyendocrinopathy syndrome type I (APS-I), mutations in the autoimmune regulator gene (AIRE) impair thymic self-tolerance induction in developing T cells. The ensuing autoimmunity particularly targets ectodermal and endocrine tissues, but chronic candidiasis usually comes fi
rst. We recently reported apparently APS-I-specific high-titer neutralizing autoantibodies against type I interferons in 100% of Finnish and Norwegian patients, mainly with two prevalent AIRE truncations. OBJECTIVES: Because variability in clinical features and age at onset in APS-I frequently results in unusual presentations, we prospectively checked the diagnostic potential of anti-interferon antibodies in additional APS-I panels with other truncations or rare missense mutations and in disease controls with chronic mucocutaneous candidiasis (CMC) but without either common AIRE mutation. DESIGN: The study was designed to detect autoantibodies against interferon-alpha2 and interferon-omega in antiviral neutralization assays. SETTING AND PATIENTS: Patients included 14 British/Irish, 15 Sardinian, and 10 Southern Italian AIRE-mutant patients with APS-I; also 19 other patients with CMC, including four families with cosegregating thyroid autoimmunity. OUTCOME: The diagnostic value of anti-interferon autoantibodies was assessed. RESULTS: We found antibodies against interferon-alpha2 and/or interferon-omega in all 39 APS-I patients vs. zero of 48 unaffected relatives and zero of 19 British/Irish CMC patients. Especially against interferon-omega, titers were nearly always high, regardless of the exact APS-I phenotype/duration or AIRE genotype, including 12 different AIRE length variants or 10 point substitutions overall (n=174 total). Strikingly, in one family with few typical APS-I features, these antibodies cosegregated over three generations with autoimmune hypothyroidism plus a dominant-negative G228W AIRE substitution. CONCLUSIONS: Otherwise restricted to patients with thymoma and/or myasthenia gravis, these precocious persistent antibodies show 98% or higher sensitivity and APS-I specificity and are thus a simpler diagnostic option than detecting AIRE mutations.
Rosati A, etal., Nat Commun. 2015 Nov 2;6:8695. doi: 10.1038/ncomms9695.
The incidence and death rate of pancreatic ductal adenocarcinoma (PDAC) have increased in recent years, therefore the identification of novel targets for treatment is extremely important. Interactions between cancer and stromal cells are critically involved in tumour formation and development of met
astasis. Here we report that PDAC cells secrete BAG3, which binds and activates macrophages, inducing their activation and the secretion of PDAC supporting factors. We also identify IFITM-2 as a BAG3 receptor and show that it signals through PI3K and the p38 MAPK pathways. Finally, we show that the use of an anti-BAG3 antibody results in reduced tumour growth and prevents metastasis formation in three different mouse models. In conclusion, we identify a paracrine loop involved in PDAC growth and metastatic spreading, and show that an anti-BAG3 antibody has therapeutic potential.
Through exome sequencing, we identified six individuals with biallelic loss-of-function mutations in TRIP13. All six developed Wilms tumor. Constitutional mosaic aneuploidies, microcephaly, developmental delay and seizures, which are features of mosaic variegated aneuploidy (MVA) syndrome, were more
variably present. Through functional studies, we show that TRIP13-mutant patient cells have no detectable TRIP13 and have substantial impairment of the spindle assembly checkpoint (SAC), leading to a high rate of chromosome missegregation. Accurate segregation, as well as SAC proficiency, is rescued by restoring TRIP13 function. Individuals with biallelic TRIP13 or BUB1B mutations have a high risk of embryonal tumors, and here we show that their cells display severe SAC impairment. MVA due to biallelic CEP57 mutations, or of unknown cause, is not associated with embryonal tumors and cells from these individuals show minimal SAC deficiency. These data provide insights into the complex relationships between aneuploidy and carcinogenesis.
Del Vecchio F, etal., BMC Bioinformatics. 2015 Dec 10;16:408. doi: 10.1186/s12859-015-0836-1.
BACKGROUND: Hepatocellular carcinoma (HCC) is an aggressive epithelial tumor which shows very poor prognosis and high rate of recurrence, representing an urgent problem for public healthcare. MicroRNAs (miRNAs/miRs) are a class of small, non-coding RNAs that attract great attention becaus
e of their role in regulation of processes such as cellular growth, proliferation, apoptosis. Because of the thousands of potential interactions between a single miR and target mRNAs, bioinformatics prediction tools are very useful to facilitate the task for individuating and selecting putative target genes. In this study, we present a chemically-induced HCC mouse model to identify differential expression of miRNAs during the progression of the hepatic injury up to HCC onset. In addition, we describe an established bioinformatics approach to highlight putative target genes and protein interaction networks where they are involved. RESULTS: We describe four miRs (miR-125a-5p, miR-27a, miR-182, miR-193b) which showed to be differentially expressed in the chemically-induced HCC mouse model. The miRs were subjected to four of the most used predictions tools and 15 predicted target genes were identified. The expression of one (ANK3) among the 15 predicted targets was further validated by immunoblotting. Then, enrichment annotation analysis was performed revealing significant clusters, including some playing a role in ion transporter activity, regulation of receptor protein serine/threonine kinase signaling pathway, protein import into nucleus, regulation of intracellular protein transport, regulation of cell adhesion, growth factor binding, and regulation of TGF-beta/SMAD signaling pathway. A network construction was created and links between the selected miRs, the predicted targets as well as the possible interactions among them and other proteins were built up. CONCLUSIONS: In this study, we combined miRNA expression analysis, obtained by an in vivo HCC mouse model, with a bioinformatics-based workflow. New genes, pathways and protein interactions, putatively involved in HCC initiation and progression, were identified and explored.
Michel V, etal., Dev Biol 2005 Apr 15;280(2):281-94.
Cadherin 23 is required for normal development of the sensory hair bundle, and recent evidence suggests it is a component of the tip links, filamentous structures thought to gate the hair cells' mechano-electrical transducer channels. Antibodies against unique peptide epitopes were used to study the
properties of cadherin 23 and its spatio-temporal expression patterns in developing cochlear hair cells. In the rat, intra- and extracellular domain epitopes are readily detected in the developing hair bundle between E18 and P5, and become progressively restricted to the distal tip of the hair bundle. From P13 onwards, these epitopes are no longer detected in hair bundles, but immunoreactivity is observed in the apical, vesicle-rich, pericuticular region of the hair cell. In the P2-P3 mouse cochlea, immunogold labeling reveals cadherin 23 is associated with kinocilial links and transient lateral links located between and within stereociliary rows. At this stage, the cadherin 23 ectodomain epitope remains on the hair bundle following BAPTA or La(3+) treatment, but is lost following exposure to the protease subtilisin. In contrast, mechano-electrical transduction is abolished by BAPTA but unaffected by subtilisin. These results suggest cadherin 23 is associated with transient lateral links that have properties distinct from those of the tip-link.
Salvi M, etal., J Biol Chem. 2007 Aug 17;282(33):24407-15. Epub 2007 Jun 18.
Highly purified rat liver mitochondria (RLM) when exposed to tert-butylhydroperoxide undergo matrix swelling, membrane potential collapse, and oxidation of glutathione and pyridine nucleotides, all events attributable to the induction of mitochondrial permeability transition. Instead, RLM, if treate
d with the same or higher amounts of H2O2 or tyramine, are insensitive or only partially sensitive, respectively, to mitochondrial permeability transition. In addition, the block of respiration by antimycin A added to RLM respiring in state 4 conditions, or the addition of H2O2, results in O2 generation, which is blocked by the catalase inhibitors aminotriazole or KCN. In this regard, H2O2 decomposition yields molecular oxygen in a 2:1 stoichiometry, consistent with a catalytic mechanism with a rate constant of 0.0346 s(-1). The rate of H2O2 consumption is not influenced by respiratory substrates, succinate or glutamate-malate, nor by N-ethylmaleimide, suggesting that cytochrome c oxidase and the glutathione-glutathione peroxidase system are not significantly involved in this process. Instead, H2O2 consumption is considerably inhibited by KCN or aminotriazole, indicating activity by a hemoprotein. All these observations are compatible with the presence of endogenous heme-containing catalase with an activity of 825 +/- 15 units, which contributes to mitochondrial protection against endogenous or exogenous H2O2. Mitochondrial catalase in liver most probably represents regulatory control of bioenergetic metabolism, but it may also be proposed for new therapeutic strategies against liver diseases. The constitutive presence of catalase inside mitochondria is demonstrated by several methodological approaches as follows: biochemical fractionating, proteinase K sensitivity, and immunogold electron microscopy on isolated RLM and whole rat liver tissue.
Several genetic mutations affecting the development and function of mammalian hair cells have been shown to cause deafness but not vestibular defects, most likely because vestibular deficits are sometimes centrally compensated. The study of hair cell physiology is thus a powerful direct approach to
ascertain the functional status of the vestibular end organs. Deletion of Epidermal growth factor receptor pathway substrate 8 (Eps8), a gene involved in actin remodeling, has been shown to cause deafness in mice. While both inner and outer hair cells from Eps8 knockout (KO) mice showed abnormally short stereocilia, inner hair cells (IHCs) also failed to acquire mature-type ion channels. Despite the fact that Eps8 is also expressed in vestibular hair cells, Eps8 KO mice show no vestibular deficits. In the present study we have investigated the properties of vestibular Type I and Type II hair cells in Eps8-KO mice and compared them to those of cochlear IHCs. In the absence of Eps8, vestibular hair cells show normally long kinocilia, significantly shorter stereocilia and a normal pattern of basolateral voltage-dependent ion channels. We have also found that while vestibular hair cells from Eps8 KO mice show normal voltage responses to injected sinusoidal currents, which were used to mimic the mechanoelectrical transducer current, IHCs lose their ability to synchronize their responses to the stimulus. We conclude that the absence of Eps8 produces a weaker phenotype in vestibular hair cells compared to cochlear IHCs, since it affects the hair bundle morphology but not the basolateral membrane currents. This difference is likely to explain the absence of obvious vestibular dysfunction in Eps8 KO mice.
INTRODUCTION: Lung cancer is the leading global cause of cancer-related mortality and is associated with poor prognosis. To improve survival rates of lung cancer patients, better understanding of tumorigenic mechanisms is necessary, which may lead to development of new therapeutic strategies. The h
OGG1 and NTH1 genes act in the DNA BER repair pathway and their involvement in lung cancer pathogenesis has been analyzed in several populations. METHODS: We analyzed targeted regions of the hOGG1 and NTH1 genes in 96 Brazilian patients with non-small-cell lung cancer (NSCLC) and 89 cancer-free, ethnically matched controls. RESULTS: The NTH1 c.98G>T polymorphism rs2302172 (p = 0.02 and p = 0.02 for allele and genotype frequency between cases and controls, respectively) and the 140-17C> T variant (rs2233518) (p = 0.02 and p = 0.02 for allele and genotype frequency between cases and controls, respectively) were detected in four lung cancer cases (4 %) while the NTH1 Q131K (C391A) polymorphism was found in seven lung cancer cases (7 %) (p = 0.001 and p = 0.008, for allele and genotype frequency between cases and controls, respectively). None of these sequence variants were detected in controls. The Ser326Cys (C1245G, rs1052133) polymorphism in the OGG1 gene was detected in 42 % of analyzed NSCLC patients and in 34 % of the controls (p = 0.11 and p = 0.25 for allele and genotype frequency between cases and controls, respectively). CONCLUSIONS: Our study provides preliminary evidence that polymorphisms in OGG1 do not contribute to development of NSCLC in Brazilian patients and that NTH1 polymorphisms may be associated with NSCLC pathogenesis.
Trevisan A, etal., Toxicol Lett. 2004 Sep 10;152(2):105-10.
The effect of cis-platin on erythrocyte aminolevulinic acid dehydratase (ALAD) activity was studied in vivo and in vitro. Young male Wistar rats were treated with a single i.p. injection of cis-platin at 2.5, 5.0, and 10.0mg/kg dose. In addition, a single i.p. injection of lead nitrate (1.0mg/kg dos
e) was administered as positive control. Experiments in vitro were also performed to elucidate the possible mechanism of action. The aminolevulinic acid dehydratase was almost completely inhibited in vitro from 0.5mM concentration, and the IC(50) was stated at 0.265 mM, 20 times higher than lead (IC(50) stated at 0.013 mM). Reduced glutathione, partially but significantly, reactivated in vitro the enzyme treated with cis-platin (0.5 and 5.0mM), whereas zinc showed a positive, significant effect with the higher dose (5.0mM) only. On the contrary, inhibition caused by lead (0.005 mM) was partially, but significantly restored by reduced glutathione, and, almost completely, by zinc. The experiments in vivo show that cis-platin causes a dose- and time-dependent inhibition of ALAD activity with 5.0 and 10.0mg/kg dose, until 66 and 33% of the control activity 96 h after treatment, respectively. The results show that erythrocyte ALAD is sensitive to cis-platin and suggest that the mechanism of enzyme inhibition is a direct interaction with sulfhydryl groups, whereas zinc site appears involved with the higher doses only. This mechanism appears different from lead that prevalently inhibits ALAD removing zinc from the enzyme, other than interacting with sulfhydryl groups.
OBJECTIVE: The aim of this study was to investigate the presence of germline mutations in the CDKN1B gene that encodes the cyclin-dependent kinase (Cdk) inhibitor p27 in multiple endocrine neoplasia 1 (MEN1)-like Spanish index patients. The CDKN1B gene has recently been identified as a tumor suscept
ibility gene for MEN4, with six germline mutations reported so far in patients with a MEN-like phenotype but negative for MEN1 mutations. DESIGN AND METHODS: Fifteen Spanish index cases with MEN-like symptoms were screened for mutations in the CDKN1B gene and the mutant variant was studied functionally by transcription/translation assays in vitro and in transiently transfected HeLa cells. RESULTS: We report the identification of a heterozygous GAGA deletion in the 5'-UTR of CDKN1B, NM_004064.3:c.-32_-29del, in a patient affected by gastric carcinoid tumor and hyperparathyroidism. This deletion falls inside the region that is responsible for CDKN1B transcription and is predicted to destroy a secondary stem and loop structure that includes the GAGAGA element responsible for ribosome recruitment. Accordingly, in vitro studies of coupled transcription/translation assays and transient transfection in HeLa cells showed that the GAGA deletion in the CDKN1B 5'-UTR significantly impairs the transcription of downstream reporter luciferase (of approximately 40-60%) and, possibly, the translation of the corresponding mRNA. This mutation was associated with a significant reduction in the amount of CDKN1B mRNA in peripheral blood leukocytes from the patient, as demonstrated by quantitative real-time PCR. CONCLUSIONS: Our results confirm that germline CDKN1B mutations may predispose to a human MEN4 condition and add novel evidence that alteration in the transcription/translation rate of CDKN1B mRNA might be the mechanism implicated in tumor susceptibility.
Caleshu C, etal., Am J Med Genet A. 2011 Sep;155A(9):2229-35. doi: 10.1002/ajmg.a.34097. Epub 2011 Aug 5.
Mutations in genes that encode components of the sarcomere are well established as the cause of hypertrophic and dilated cardiomyopathies. Sarcomere genes, however, are increasingly being associated with other cardiomyopathies. One phenotype more recently recognized as a disease of the sarcomere is
restrictive cardiomyopathy (RCM). We report on two patients with RCM associated with multiple mutations in sarcomere genes not previously associated with RCM. Patient 1 presented with NYHA Class III/IV heart failure at 22 years of age. She was diagnosed with RCM and advanced heart failure requiring heart transplantation. Sequencing of sarcomere genes revealed previously reported homozygous p.Glu143Lys mutations in MYL3, and a novel heterozygous p.Gly57Glu mutation in MYL2. The patient's mother is a double heterozygote for these mutations, with no evidence of cardiomyopathy. Patient 2 presented at 35 years of age with volume overload while hospitalized for oophorectomy. She was diagnosed with RCM and is being evaluated for heart transplantation. Sarcomere gene sequencing identified homozygous p.Asn279His mutations in TPM1. The patient's parents are consanguineous and confirmed heterozygotes. Her father was diagnosed with HCM at 42 years of age. This is the first report of mutations in TPM1, MYL3, and MYL2 associated with primary, non-hypertrophied RCM. The association of more sarcomere genes with RCM provides further evidence that mutations in the various sarcomere genes can cause different cardiomyopathy phenotypes. These cases also contribute to the growing body of evidence that multiple mutations have an additive effect on the severity of cardiomyopathies.
Given the critical role of pattern recognition receptors (PRRs) in acid nucleic recognition in the initiation of innate immunity and the orchestration of adaptive immunity, the aim of this study was to determine whether any heterogeneity of PRR expression in the airway tracts of infants with respira
tory syncytial virus (RSV) infection might explain the broad clinical spectrum of RSV-associated bronchiolitis in infants. For this purpose, the levels of melanoma differentiation-associated protein-5 (MDA-5), retinoic acid inducible gene-1 (RIG-1), and Toll-like receptor 3 (TLR-3), TLR-7, TLR-8, and TLR-9 mRNAs were evaluated, using TaqMan quantitative reverse transcription-PCR, in cells from nasopharyngeal washes collected from 157 infants suffering from acute bronchiolitis whether or not they were associated with respiratory viruses. High interindividual variability was observed in both virus-positive and -negative infants; however, the relative gene expression levels of MDA-5, RIG-1, TLR-7, and TLR-8 were significantly higher in the virus-infected group, whereas the expression levels of TLR-3 and TLR-9 were not significantly different. The differences in the gene expression of MDA-5, RIG-1, TLR-7, and TLR-8 were more evident in infants with RSV infection than in those with bocavirus or rhinovirus infection. In RSV-infected infants, PRR-mRNA levels also were analyzed in relation to interferon protein levels, viral load, clinical severity, days of hospitalization, age, and body weight. A significant positive correlation was observed only between RSV viral load and RIG-1 mRNA levels. These findings provide the first direct evidence that, in infants with respiratory virus-associated bronchiolitis, especially RSV, there are substantial changes in PRR gene expression; this likely is an important determinant of the clinical outcome of bronchiolitis.
OBJECTIVE: Familial isolated primary hyperparathyroidism (FIPH) can result from either incomplete expression of a syndromic form of familial primary hyperparathyroidism [multiple endocrine neoplasia type 1 (MEN 1), hyperparathyroidism-jaw tumour syndrome (HPT-JT) or familial hypocalciuric hypercalca
emia (FHH)] or still unrecognized causes. Design Genetic analyses of MEN1, HRPT2 and CASR genes in FIHP. PATIENTS: Seven well-characterized Italian kindreds with FIHP, with negative clinical features for MEN 1, HPT-JT and FHH. The mean age (+/- SD) at diagnosis was 45 +/- 17 years (range 18-70 years) in the probands and 42 +/- 18 years (range 15-69 years) in the other affected subjects. MEASUREMENTS: Direct sequencing of germline DNA of the MEN1, HRPT2 and CASR genes from probands. The region of interest was amplified in some family members. RESULTS: Germline MEN1 mutations were detected in three kindreds. Multiglandular involvement was found in all but one affected subject belonging to the three kindreds with MEN1 mutations. In these patients persistence/relapse of the disease was observed unless an extensive parathyroidectomy (excision of 3(1)/(2) glands) had been performed, with the exception of one patient, who is currently normocalcaemic 168 months after excision of two glands. No mutations of MEN1, HRPT2 and CASR genes were identified in the remaining four families. CONCLUSIONS: MEN1 genotyping appears worthwhile in FIHP families, as the finding of mutation(s) may predict multiglandular involvement and therefore have practical surgical implications, and prompt further investigation in the family, with the possibility of identifying new cases and beginning a programme of periodic surveillance for emergence of tumours in all carriers.
Rigiracciolo DC, etal., Oncotarget. 2016 Jan 5;7(1):94-111. doi: 10.18632/oncotarget.6475.
Aldosterone induces relevant effects binding to the mineralcorticoid receptor (MR), which acts as a ligand-gated transcription factor. Alternate mechanisms can mediate the action of aldosterone such as the activation of epidermal growth factor receptor (EGFR), MAPK/ERK, transcription factors and ion
channels. The G-protein estrogen receptor (GPER) has been involved in the stimulatory effects of estrogenic signalling in breast cancer. GPER has been also shown to contribute to certain responses to aldosterone, however the role played by GPER and the molecular mechanisms implicated remain to be fully understood. Here, we evaluated the involvement of GPER in the stimulatory action exerted by aldosterone in breast cancer cells and breast tumor derived endothelial cells (B-TEC). Competition assays, gene expression and silencing studies, immunoblotting and immunofluorescence experiments, cell proliferation and migration were performed in order to provide novel insights into the role of GPER in the aldosterone-activated signalling. Our results demonstrate that aldosterone triggers the EGFR/ERK transduction pathway in a MR- and GPER-dependent manner. Aldosterone does not bind to GPER, it however induces the direct interaction between MR and GPER as well as between GPER and EGFR. Next, we ascertain that the up-regulation of the Na+/H+ exchanger-1 (NHE-1) induced by aldosterone involves MR and GPER. Biologically, both MR and GPER contribute to the proliferation and migration of breast and endothelial cancer cells mediated by NHE-1 upon aldosterone exposure. Our data further extend the current knowledge on the molecular mechanisms through which GPER may contribute to the stimulatory action elicited by aldosterone in breast cancer.
We investigated the frequency of the GSTM1 genotypes in 70 Brazilian patients with oral squamous cell carcinoma (OSCC) and 82 age-sex matched controls. The GSTM1 genotypes were studied by PCR-based methods. The frequency of male patients with OSCC and null for the GSTM1 (70.5%) was statistically dif
ferent from the male patients from the control group (48.5%) (Odds Ratio, OR=2.53, 95% CI=1.22-5.24, P<0.05). The frequency of the GSTM1 null genotype (0/0) in the group with OSCC (65.7%) was statistically different from the controls (48.7%) (OR=2.01, 95% CI=1.04-3.88, P<0.05). The prevalence of GSTM1 deficiency (null) was significantly higher for patients with oral cancer of the floor of the mouth (OR=3.67, 95% CI=1.11-12.11, P<0.05). In conclusion, the GSTM1 null genotype may increase the risk for OSCC development.
Piacentini R, etal., Sci Rep. 2015 Oct 21;5:15444. doi: 10.1038/srep15444.
Increasing evidence suggests that recurrent Herpes Simplex Virus type 1 (HSV-1) infection spreading to the CNS is a risk factor for Alzheimer's Disease (AD) but the underlying mechanisms have not been fully elucidated yet. Here we demonstrate that in cultured mouse cortical neurons HSV-1 induced Ca
(2+)-dependent activation of glycogen synthase kinase (GSK)-3. This event was critical for the HSV-1-dependent phosphorylation of amyloid precursor protein (APP) at Thr668 and the following intraneuronal accumulation of amyloid-beta protein (Abeta). HSV-1-infected neurons also exhibited: i) significantly reduced expression of the presynaptic proteins synapsin-1 and synaptophysin; ii) depressed synaptic transmission. These effects depended on GSK-3 activation and intraneuronal accumulation of Abeta. In fact, either the selective GSK-3 inhibitor, SB216763, or a specific antibody recognizing Abeta (4G8) significantly counteracted the effects induced by HSV-1 at the synaptic level. Moreover, in neurons derived from APP KO mice and infected with HSV-1 Abeta accumulation was not found and synaptic protein expression was only slightly reduced when compared to wild-type infected neurons. These data further support our contention that HSV-1 infections spreading to the CNS may contribute to AD phenotype.
Antonelli A, etal., World J Gastroenterol. 2009 Oct 28;15(40):5074-9.
AIM: To evaluate serum levels of N-terminal pro-brain natriuretic peptide (NTproBNP) and tumor necrosis factor alpha (TNF-alpha) in a large series of patients with hepatitis C associated with mixed cryoglobulinemia (MC+HCV). METHODS: Serum NTproBNP and TNF-alpha levels were assayed in 50 patients wi
th MC+HCV, and in 50 sex- and age-matched controls. RESULTS: Cryoglobulinemic patients showed significantly higher mean NTproBNP and TNF-alpha levels than controls (P < 0.001; Mann-Whitney U test). By defining high NTproBNP level as a value higher than 125 pg/mL (the single cut-off point for outpatients under 75 years of age), 30% of MC+HCV and 6% of controls had high NTproBNP (c2, P < 0.01). With a cut-off point of 300 pg/mL (used to rule out heart failure (HF) in patients under 75 years of age), 8% of MC+HCV and 0 controls had high NTproBNP (c2, P < 0.04). With a cut-off point of 900 pg/mL (used for ruling in HF in patients aged 50-75 years; such as the patients of our study), 6% of MC+HCV and 0 controls had high NTproBNP (c2, P = 0.08). CONCLUSION: The study demonstrates high levels of circulating NTproBNP and TNF-alpha in MC+HCV patients. The increase of NTproBNP may indicate the presence of a subclinical cardiac dysfunction.
In sarcoid granulomas, apoptotic events are reduced, which explains their characteristic long-lasting inflammation. We have described that interferon-gamma (IFN-gamma) inhibits apoptosis in macrophages through the expression of p21(Waf1). Here, we explore the molecular mechanisms involved in the inh
ibition of apoptosis in sarcoid granulomas. We analyzed skin biopsies from 19 sarcoidosis patients and 16 controls. Total RNA was subjected to semiquantitative reverse transcriptase-polymerase chain reaction analysis. There was no difference found in the expression of proapoptotic (Bax and Bcl-X(s)) or antiapoptotic (Bcl-2 and Bcl-X(L)) genes nor in the expression of the tumor suppressor gene p53. Furthermore, the expression of IFN-gamma and the cdk inhibitors p21(Waf1) and p27(Kip1) were analyzed. IFN-gamma was detected in 37% of the sarcoidosis patients, and controls were negative (P<0.02). In addition, a higher proportion of patients expressing p21(Waf1) (58%) versus controls (12%) was found (P<0.005). There was a significant correlation between the expression of IFN-gamma and p21(Waf1) (r=0.69) and between p21(Waf1) and fibronectin (r=0.65). Finally, using immunohistochemistry, high p21(Waf1) reactivity was observed inside the granuloma. We conclude that the high levels of p21(Waf1) in sarcoidosis may explain the absence of apoptosis in the granuloma and the persistence of inflammation.
Brambilla M, etal., Thromb Haemost. 2015 Aug 31;114(3):579-92. doi: 10.1160/TH14-10-0830. Epub 2015 Jun 11.
Tissue factor (TF), the main activator of the blood coagulation cascade, has been shown to be expressed by platelets. Despite the evidence that both megakaryocytes and platelets express TF mRNA, and that platelets can make de novo protein synthesis, the main mechanism thought to be responsible for t
he presence of TF within platelets is through the uptake of TF positive microparticles. In this study we assessed 1) whether human megakaryocytes synthesise TF and transfer it to platelets and 2) the contribution of platelet-TF to the platelet hemostatic capacity. In order to avoid the cross-talk with circulating microparticles, we took advantage from an in vitro cultured megakaryoblastic cell line (Meg-01) able to differentiate into megakaryocytes releasing platelet-like particles. We show that functionally active TF is expressed in human megakaryoblasts, increased in megakaryocytes, and is transferred to a subset of shed platelets where it contributes to clot formation. These data were all confirmed in human CD34pos-derived megakaryocytes and in their released platelets. The effect of TF silencing in Meg-megakaryoblasts resulted in a significant reduction of TF expression in these cells and also in Meg-megakaryocytes and Meg-platelets. Moreover, the contribution of platelet-TF to the platelet hemostatic capacity was highlighted by the significant delay in the kinetic of thrombin formation observed in platelets released by TF-silenced megakaryocytes. These findings provide evidences that TF is an endogenously synthesised protein that characterises megakaryocyte maturation and that it is transferred to a subset of newly-released platelets where it is functionally active and able to trigger thrombin generation.
The planar cell polarity (PCP) pathway controls the process of convergent extension (CE) during gastrulation and neural tube closure, and has been implicated in the pathogenesis of neural tube defects (NTDs) in animal models and human cohorts. In this study, we analyzed the role of one core PCP gene
PRICKLE1 in these malformations. We screened this gene in 810 unrelated NTD patients and identified seven rare missense heterozygous mutations that were absent in all controls analyzed and predicted to be functionally deleterious using bioinformatics. Functional validation of five PRICKLE1 variants in a zebrafish model demonstrated that one variant, p.Arg682Cys, antagonized the CE phenotype induced by the wild-type zebrafish prickle1a (zpk1a) in a dominant fashion. Our study demonstrates that PRICKLE1 could act as a predisposing factor to human NTDs and further expands our knowledge of the role of PCP genes in the pathogenesis of these malformations.
Parolaro D, etal., Eur J Pharmacol. 1993 Feb 15;244(3):211-22.
In situ hybridization histochemistry has been used to detect the basal distribution of mRNA encoding the alpha subunit of Gs, Go and Gi2 proteins throughout the rat brain. Based on these data we investigated the effect of chronic morphine on the content of these G protein alpha subunits mRNA. We obs
erved an increase in the expression of alpha s and alpha o messages of chronically morphine-treated animals, while no changes were seen in alpha i2 mRNA. Specifically a 30% increase in expression for alpha s was seen only in the paraventricular nucleus of hypothalamus and a 20% elevation for alpha o was detected in the claustrum and endopiriform nucleus. Immunoblotting analysis was used to correlate the changes in alpha s and alpha o messages with equivalent changes in protein levels. Chronic morphine significantly increased alpha s amounts in the hypothalamus (70%), and produced a minor elevation (30%) in G alpha o levels in the olfactory area. Our results indicate that in discrete brain regions altered G protein expression is part of the adaptive changes underlying opiate tolerance.
Increasing evidence suggests a critical role for oxidative and nitrosative stress in the pathogenesis of most important neurodegenerative disorders. Parkinson's disease (PD) is a neurodegenerative disease characterized by a severe depletion in number of dopaminergic cells of the substantia nigra (SN
). Administration of L-DOPA (LD) is the more effective treatment for patients with PD. However, the vast majority of patients suffer LD-related complications, which represent the major problem in the clinical management of PD. In the present study, LD administration to rats resulted in a significant dose-dependent increase in Hsp70 synthesis which was specific for the SN. The amount of 70 kDa protein increased after 6 h treatment reaching the maximal induction after 24-48 h. Induction of Hsp70 in the SN was associated with a significant increase in constitutive Hsc70 and mitochondrial Hsp60 stress proteins, and with increased expression of mitochondrial complex I whereas no significant changes were found in the activity of complex IV. In the same experimental conditions, a significant decrease in reduced glutathione was observed, which was associated with an increased content of oxidized glutathione content as well as nitric oxide (NO) synthase activity, NO metabolites and nitrotyrosine immunoreactivity. Interestingly, Hsp70 induction, iNOS up-regulation and nitrotyrosine formation have been confirmed also in SN and striatum of rats treated with LD and carbidopa, this latter being an inhibitor of the peripheral DOPA decarboxylase. Our data are in favor of the importance of the heat shock signal pathway as a basic mechanism of defense against neurotoxicity elicited by free radical oxygen and nitrogen species produced in aging and neurodegenerative disorders.
Tarantino P, etal., Am J Med Genet B Neuropsychiatr Genet. 2011 Jan;156B(1):104-7. doi: 10.1002/ajmg.b.31129. Epub 2010 Nov 2.
The major component of Lewy Bodies (LB), the pathological hallmark of Parkinson's disease (PD) is alpha-synuclein, most prominently phosphorylated at serine 129. G-protein coupled receptor kinase 5 (GRK5) has been reported to phosphorylate alpha-synuclein in vitro, enhancing the alpha-synuclein toxi
city to dopaminergic neurons in Drosophila model. Moreover, GRK5 was found in LBs from brain of PD patients. A genetic association study performed in the Japanese population revealed haplotypic association of the GRK5 gene with susceptibility to sporadic PD. We aimed at investigating whether four polymorphisms within the GRK5 gene (rs871196, rs2420616, rs7069375, rs4752293) could represent a risk factor for sporadic PD in Southern Italy. We genotyped 446 patients with PD and 450 controls for these markers and did not find any significant association with the disease at allelic, genotypic and haplotypic level. Our results indicate that the GRK5 gene does not confer risk to sporadic PD in our sample from Southern Italy.
Zuccotti A, etal., J Neurosci. 2012 Jun 20;32(25):8545-53. doi: 10.1523/JNEUROSCI.1247-12.2012.
The precision of sound information transmitted to the brain depends on the transfer characteristics of the inner hair cell (IHC) ribbon synapse and its multiple contacting auditory fibers. We found that brain derived neurotrophic factor (BDNF) differentially influences IHC characteristics in the int
act and injured cochlea. Using conditional knock-out mice (BDNF(Pax2) KO) we found that resting membrane potentials, membrane capacitance and resting linear leak conductance of adult BDNF(Pax2) KO IHCs showed a normal maturation. Likewise, in BDNF(Pax2) KO membrane capacitance (DeltaC(m)) as a function of inward calcium current (I(Ca)) follows the linear relationship typical for normal adult IHCs. In contrast the maximal DeltaC(m), but not the maximal size of the calcium current, was significantly reduced by 45% in basal but not in apical cochlear turns in BDNF(Pax2) KO IHCs. Maximal DeltaC(m) correlated with a loss of IHC ribbons in these cochlear turns and a reduced activity of the auditory nerve (auditory brainstem response wave I). Remarkably, a noise-induced loss of IHC ribbons, followed by reduced activity of the auditory nerve and reduced centrally generated wave II and III observed in control mice, was prevented in equally noise-exposed BDNF(Pax2) KO mice. Data suggest that BDNF expressed in the cochlea is essential for maintenance of adult IHC transmitter release sites and that BDNF upholds opposing afferents in high-frequency turns and scales them down following noise exposure.
Shashi V, etal., EMBO J. 2018 Dec 3;37(23):e100540. doi: 10.15252/embj.2018100540. Epub 2018 Nov 12.
A set of glutamylases and deglutamylases controls levels of tubulin polyglutamylation, a prominent post-translational modification of neuronal microtubules. Defective tubulin polyglutamylation was first linked to neurodegeneration in the Purkinje cell degeneration (pcd) mouse, which lacks deglutamyl
ase CCP1, displays massive cerebellar atrophy, and accumulates abnormally glutamylated tubulin in degenerating neurons. We found biallelic rare and damaging variants in the gene encoding CCP1 in 13 individuals with infantile-onset neurodegeneration and confirmed the absence of functional CCP1 along with dysregulated tubulin polyglutamylation. The human disease mainly affected the cerebellum, spinal motor neurons, and peripheral nerves. We also demonstrate previously unrecognized peripheral nerve and spinal motor neuron degeneration in pcd mice, which thus recapitulated key features of the human disease. Our findings link human neurodegeneration to tubulin polyglutamylation, entailing this post-translational modification as a potential target for drug development for neurodegenerative disorders.
Lemay P, etal., J Med Genet. 2015 Jul;52(7):493-7. doi: 10.1136/jmedgenet-2015-103027. Epub 2015 Mar 24.
BACKGROUND: Neural tube defects (NTDs) are very common and severe birth defects that are caused by failure of neural tube closure and that have a complex aetiology. Anencephaly and spina bifida are severe NTDs that affect reproductive fitness and suggest a role for de novo mutations (DNMs) in their
aetiology. METHODS: We used whole-exome sequencing in 43 sporadic cases affected with myelomeningocele or anencephaly and their unaffected parents to identify DNMs in their exomes. RESULTS: We identified 42 coding DNMs in 25 cases, of which 6 were loss of function (LoF) showing a higher rate of LoF DNM in our cohort compared with control cohorts. Notably, we identified two protein-truncating DNMs in two independent cases in SHROOM3, previously associated with NTDs only in animal models. We have demonstrated a significant enrichment of LoF DNMs in this gene in NTDs compared with the gene specific DNM rate and to the DNM rate estimated from control cohorts. We also identified one nonsense DNM in PAX3 and two potentially causative missense DNMs in GRHL3 and PTPRS. CONCLUSIONS: Our study demonstrates an important role of LoF DNMs in the development of NTDs and strongly implicates SHROOM3 in its aetiology.
Leidenz FB, etal., Genet Res (Camb). 2015 Mar 30;97:e3. doi: 10.1017/S0016672315000063.
BACKGROUND: Paraganglioma syndrome type 1 (PGL1) is a rare autosomal dominant syndrome associated with multiple, overwhelmingly benign, pheochromocytomas and paragangliomas, attributed to SDHD gene mutations. OBJECTIVE: Clinically and molecularly characterize a family with uncommon malignant phenoty
pe of paragangliomas attributed to two seemingly pathogenic SDHD germline mutations. MATERIALS & METHODS: The proband presented with large bilateral carotid body tumours and family history of cervical masses in his five siblings. All family members underwent clinical examination, imaging studies (18F-FDG PET/CT) and genotyping of relevant genes. The proband was diagnosed with locally advanced paraganglioma; his hypertensive, otherwise asymptomatic father, had locally advanced pheochromocytoma and his three siblings showed multiple head and neck masses, confirmed to be paragangliomas with local metastasis. All affected patients carried two germline mutations in the SDHD gene; a previously reported nonsense mutation in exon 1 (p.Trp5X) and a novel missense mutation in exon 2 (p.Pro53Leu), highly deleterious by in silico analysis. Allelic loss at the SDHD locus was not shown for any of the analysed tumours. CONCLUSIONS: This is a rare case of malignant PGL1 with seemingly double pathogenic mutations in the SDHD gene, highlighting the possibility that the presence of both mutations is associated with the more aggressive phenotype.
Methylenetetrahydrofolate reductase status, homocysteine and lipoproteins levels have been associated with severity of disease and both rapid and sustained virological response (SVR) in patients with genotype 1 chronic hepatitis C (CHC). We aimed to assess the association of homocysteine and MTHFR s
tatus with serum cholesterol levels and their potential links to both histological findings and virological response, in patients with genotype 1 hepatitis C virus (HCV). A total of 119 consecutive patients were evaluated by biopsy and metabolic measurements. A total of 103 healthy blood donors were used as controls. Serum homocysteine and MTHFR C677T mutation were also evaluated. All patients underwent antiviral therapy with PEG-IFN alfa-2a plus ribavirin. HCV-RNA was assessed at baseline, week 4, week 12, at the end of therapy and after 6 months of follow-up. Mean serum values of homocysteine were higher in patients than in controls (15.8 ± 5.8 μg/L vs 12.5 ± 5.8 μg/L; P < 0.001), with a similar CC, CT and TT MTHFR distribution (23.6%, 48.7% and 27.7% in G1-CHC vs 34%, 48.5% and 17.5% in controls; P = 0.14). In genotype 1, HCV MTHFR TT homozygosis was independently linked to higher LDL (OR 1.016; CI 1.002-1.031; P = 0.03), but not to homocysteine. No association were found between homocysteine, MTHFR and histological features or both rapid virological response (RVR) and SVR. Low cholesterol (OR 0.988, 95%CI 0.975-0.999, P = 0.04) was independently linked to severe fibrosis, and high LDL was the only independent positive predictors of both RVR and SVR (OR 1.036; 95%CI 1.017-1.055; P < 0.001; and OR 1.016; 95%CI 1.001-1.031; P = 0.04 respectively). In patients with genotype 1 hepatitis C, showing higher homocysteine serum levels than controls, MTHFR C677T homozygosis, via modulating cholesterol levels, could interfere with liver fibrosis and response to antiviral therapy.
Ottini L, etal., Carcinogenesis. 2004 Dec;25(12):2337-43. Epub 2004 Aug 19.
Gastric carcinomas (GCs) with high-level microsatellite instability (MSI-H) are characterized by widespread mutations at coding and non-coding mononucleotide repeats. Deletions at coding mononucleotide tracts are predicted to cause frameshift mutations and alter normal protein functions. Mutations a
ffecting non-coding mononucleotide repeats may lead to functional consequences if they occur in gene regulatory regions. To investigate whether mutations in non-coding polypyrimidine tracts within cancer-related genes may contribute to the phenotype of MSI-H GCs, we analysed the poly(T)11 tract constituting an accessory splicing signal within the intron 4 of the MRE11 gene. Mutations at the intronic MRE11 poly(T)11 were evaluated by PCR-based assay in 27 MSI-H, 22 MSI-low and 29 MSI-negative GCs derived from a well-characterized series of GCs identified in a high-risk area in Tuscany, Central Italy. Deletion of 2 and 1 bp at the MRE11poly(T)11 were identified in 33 and 48% MSI-H GCs, respectively. Biallelic mutations were frequently observed (77%) in GCs harbouring 2 bp deletions. The presence of MRE11poly(T)11 2 bp deletion was associated with a totally absent or strongly reduced MRE11 immunostaining (P < 0.001) and with a positive GC family history (P = 0.046). Immunoblotting assays confirmed the absence of MRE11 expression in GCs with a 2 bp deletion. The relatively high frequency of the MRE11poly(T)11 mutations, the occurrence of biallelic mutations and the evidence of loss of protein expression indicate MRE11 as novel mutational target in MSI-H GC. Overall, our results indicate that MSI-associated mutations occurring in non-coding repeats may affect protein expression in MSI-H GC.
Neural-tube defects such as anencephaly and spina bifida constitute a group of common congenital malformations caused by complex genetic and environmental factors. We have identified three mutations in the VANGL1 gene in patients with familial types (V239I and R274Q) and a sporadic type (M328T) of t
he disease, including a spontaneous mutation (V239I) appearing in a familial setting. In a protein-protein interaction assay V239I abolished interaction of VANGL1 protein with its binding partners, disheveled-1, -2, and -3. These findings implicate VANGL1 as a risk factor in human neural-tube defects.
In about 50% of sporadic cases of retinoblastoma, no constitutive RB1 mutations are detected by conventional methods. However, recent research suggests that, at least in some of these cases, there is somatic mosaicism with respect to RB1 normal and mutant alleles. The increased availability of next
generation sequencing improves our ability to detect the exact percentage of patients with mosaicism. Using this technology, we re-tested a series of 40 patients with sporadic retinoblastoma: 10 of them had been previously classified as constitutional heterozygotes, whereas in 30 no RB1 mutations had been found in lymphocytes. In 3 of these 30 patients, we have now identified low-level mosaic variants, varying in frequency between 8 and 24%. In 7 out of the 10 cases previously classified as heterozygous from testing blood cells, we were able to test additional tissues (ocular tissues, urine and/or oral mucosa): in three of them, next generation sequencing has revealed mosaicism. Present results thus confirm that a significant fraction (6/40; 15%) of sporadic retinoblastoma cases are due to postzygotic events and that deep sequencing is an efficient method to unambiguously distinguish mosaics. Re-testing of retinoblastoma patients through next generation sequencing can thus provide new information that may have important implications with respect to genetic counseling and family care.
Nephrogenic diabetes insipidus (NDI) is an inherited disorder characterized by renal resistance to the antidiuretic effect of arginine vasopressin (AVP), resulting in polyuria, polydipsia, and hypoosmolar urine. In the vast majority of cases, NDI is associated with germ-line mutations in the vasopre
ssin receptor type 2 gene (AVPR2) and in about 8% of the cases with the water channel aquaporin-2 gene (AQP-2) mutations. To date, approximately 277 families with 185 germ-line mutations in the AVPR2 gene have been described worldwide. In the present study, the AVPR2 gene was genotyped in eight unrelated Brazilian kindred with NDI. In five of these NDI families, novel mutations were noted (S54R, I130L, S187R, 219delT, and R230P), whereas three seemingly unrelated probands were found to harbor previously described AVPR2 gene mutations (R106C, R137H, R337X). Additionally a novel polymorphism (V281V) was detected. In conclusion, although NDI is a rare disease, the findings of mutations scattered over the entire coding region of the AVPR2 gene are a valuable model to determine structure function relationship in G-protein-coupled receptor related diseases. Furthermore, our data indicate that in Brazil the spectrum of AVPR2 gene mutations is "family specific".
Gabriel LA, etal., Arch Ophthalmol. 2011 Jun;129(6):781-4. doi: 10.1001/archophthalmol.2011.113.
OBJECTIVES: To describe new ocular findings associated with oculodentodigital dysplasia (ODDD) and a novel mutation in the connexin 43 transmembrane domain. DESIGN: Oculodentodigital dysplasia is a rare autosomal dominant disease characterized by multiple systemic abnormalities, most commonly of the
ocular, nasal, dental, and limb structures. Herein, we studied 2 patients with ODDD. We describe their clinical findings and 2 ocular abnormalities not previously emphasized or reported. RESULTS: Optic nerve and retinal dysplasia was observed in both patients, and ciliary body cysts were observed in 1 patient. Both patients carried isolated in-frame deletion and missense mutations of the GJA1 gene on chromosome 6. CONCLUSIONS: Optic nerve and retinal dysplasia had not been emphasized as ocular manifestations of ODDD. Ciliary body cysts have not previously been reported in association with ODDD. CLINICAL RELEVANCE: Our findings support the potential significance of connexin 43 in the retina, optic nerve, and ciliary body. Retinal and optic nerve dysplasia may be more common than previously appreciated and may be associated with reduced vision. In addition, the ciliary body cysts observed in 1 patient may be secondary to weakened cellular adhesions between ciliary body pigmented and nonpigmented epithelium associated with the in-frame deletion identified in the affected patient. The presence of these cysts may exacerbate glaucoma or complicate its management.
Duncker SV, etal., J Neurosci. 2013 May 29;33(22):9508-19. doi: 10.1523/JNEUROSCI.5689-12.2013.
The encoding of auditory information with indefatigable precision requires efficient resupply of vesicles at inner hair cell (IHC) ribbon synapses. Otoferlin, a transmembrane protein responsible for deafness in DFNB9 families, has been postulated to act as a calcium sensor for exocytosis as well as
to be involved in rapid vesicle replenishment of IHCs. However, the molecular basis of vesicle recycling in IHCs is largely unknown. In the present study, we used high-resolution liquid chromatography coupled with mass spectrometry to copurify otoferlin interaction partners in the mammalian cochlea. We identified multiple subunits of the adaptor protein complex AP-2 (CLAP), an essential component of clathrin-mediated endocytosis, as binding partners of otoferlin in rats and mice. The interaction between otoferlin and AP-2 was confirmed by coimmunoprecipitation. We also found that AP-2 interacts with myosin VI, another otoferlin binding partner important for clathrin-mediated endocytosis (CME). The expression of AP-2 in IHCs was verified by reverse transcription PCR. Confocal microscopy experiments revealed that the expression of AP-2 and its colocalization with otoferlin is confined to mature IHCs. When CME was inhibited by blocking dynamin action, real-time changes in membrane capacitance showed impaired synaptic vesicle replenishment in mature but not immature IHCs. We suggest that an otoferlin-AP-2 interaction drives Ca(2+)- and stimulus-dependent compensating CME in mature IHCs.
The mechanoelectrical transducer (MET) channels located at the stereocilia tip of cochlear hair cells are crucial to convert the mechanical energy of sound into receptor potentials, but the identity of its pore-forming subunits remains uncertain. Piezo1, which has been identified in the transcriptom
e of mammalian cochlear hair cells, encodes a transmembrane protein that forms mechanosensitive channels in other tissues. We investigated the properties of the MET channel in outer hair cells (OHCs) of Piezo1 mice (postnatal day 6-9). The MET current was elicited by deflecting the hair bundle of OHCs using sinewave and step stimuli from a piezo-driven fluid jet. Apical and basal OHCs were investigated because the properties of the MET channel vary along the cochlea. We found that the maximal MET current amplitude and the resting open probability of the MET channel in OHCs were similar between Piezo1(+/-) haploinsufficient mice and wild-type littermates. The sensitivity to block by the permeant MET channel blocker dihydrostreptomycin was also similar between the two genotypes. Finally, the anomalous mechano-gated current, which is activated by sheer force and which is tip-link independent, was unaffected in OHCs from Piezo1(+/-) haploinsufficient mice. Our results suggest that Piezo1 is unlikely to be a component of the MET channel complex in mammalian cochlear OHCs.
Ware J, etal., J Clin Invest. 1993 Sep;92(3):1213-20.
Leucine-rich repeats are a conserved structural motif, of yet undefined significance, found in a group of proteins from different species. Among these are the four components of the human platelet glycoprotein Ib-IX-V complex, a membrane receptor that performs an essential role in the thrombogenic f
unction of platelets by interacting with the adhesive protein, von Willebrand factor. We have found that a single amino acid substitution (Ala156-->Val) within one of the six leucine-rich repeats in the alpha-subunit of glycoprotein Ib results in a variant form of the congenital bleeding disorder, Bernard-Soulier syndrome, characterized by giant dysfunctional platelets. Genetic studies of the propositus and his family members were complemented by immunological and functional analysis of expressed recombinant GP Ib alpha fragments to demonstrate that the observed mutation is the cause of defective von Willebrand factor binding. These studies define the molecular basis of the Bernard-Soulier syndrome within this family and demonstrate that structural integrity of a leucine-rich repeat is necessary for normal function of the glycoprotein Ib-IX-V receptor complex and, possibly, for normal platelet morphology.
Increasing evidence links dysregulation of NR2B-containing N-methyl-D-aspartate receptor remodelling and trafficking to Alzheimer's disease (AD). This theme offers the possibility that the GRIN2B gene, encoding this selective NR2B subunit, represents a potential molecular modulating factor for this
disease. Based on this hypothesis, we carried out a mutation scanning of exons and flanking regions of GRIN2B in a well-characterized cohort of AD patients, recruited from Southern Italy. A "de novo" p.K1293R mutation, affecting a highly conserved residue of the protein in the C-terminal domain, was observed for the first time in a woman with familial AD, as the only genetic alteration of relevance. Moreover, an association study between the other detected sequence variants and AD was performed. In particular, the study was focused on five identified single nucleotide polymorphisms: rs7301328, rs1805482, rs3026160, rs1806191 and rs1806201, highlighting a significant contribution from the GRIN2B rs1806201 T allele towards disease susceptibility [adjusted odds ratio (OR) = 1.92, 95% confidence interval (CI) 1.40-2.63, p < 0.001, after correction for sex, age, and APOE e4 genotype]. This was confirmed by haplotype analysis that identified a specific haplotype, carrying the rs1806201 T allele (CCCTC), over-represented in patients versus controls (adjusted OR = 6.03; p < 0.0001). Although the pathogenic role of the GRIN2B-K1293R mutation in AD is not clear, our data advocate that genetic variability in the GRIN2B gene, involved in synaptic functioning, might provide valuable insights into disease pathogenesis, continuing to attract significant attention in biomedical research on its genetic and functional role.
Lisi S, etal., Proc Natl Acad Sci U S A. 2003 Dec 9;100(25):14858-63. Epub 2003 Dec 1.
Hormone secretion by thyrocytes occurs by fluid phase uptake and lysosomal degradation of the prohormone thyroglobulin (Tg). However, some Tg internalized by megalin bypasses lysosomes and is transcytosed across cells and released into the bloodstream. Because the hormone content of Tg is variable,
we investigated whether this affects transcytosis. We found that rat Tg with a low hormone content [low-hormonogenic rat Tg (low-horm-rTg)] is transcytosed by megalin across thyroid FRTL-5 cells to a greater extent than rat Tg with a high hormone content [hormonogenic rat Tg (horm-rTg)]. In immunoprecipitation experiments, the Tg sequence Arg-2489-Lys-2503 (required for binding to megalin and heparan sulfate proteoglycans) was found to be more exposed in low-horm-rTg, which accounted for its preferential transcytosis. Thus, removal of surface heparan sulfate proteoglycans from FRTL-5 cells or blocking of 2489-2503 reduced transcytosis of low-horm-rTg to a greater extent than that of horm-rTg. Preferential transcytosis of low-horm-rTg affected hormone release. Thus, the increase in hormone release from horm-rTg in FRTL-5 cells determined by megalin blocking (due to reduced transcytosis and enhanced Tg degradation) was rescued by low-horm-rTg, suggesting that megalin is required for effective hormone release. This finding was confirmed in a small number of megalin-deficient mice, which had serological features resembling mild hypothyroidism. Reduced hormone formation within Tg in vivo, due to treatment of rats with aminotriazole or of patients with Graves' disease with methimazole, resulted in increased Tg transcytosis via megalin, in confirmation of results with FRTL-5 cells. Our study points to a major role of megalin in thyroid homeostasis with possible implications in thyroid diseases.
The role of endogenous interferon-gamma (IFN gamma) in the development of insulin-dependent diabetes mellitus (IDDM) in diabetes-prone BB rats was evaluated. Several groups of these animals were treated under different, experimental conditions with a purified polyclonal antibody (Ab), antirat IFN ga
mma. The results show that when administered at doses of 100 or 200 micrograms/week from the 30/33th until the 105th day of age, the anti-IFN gamma Ab reversibly reduced the incidence of IDDM compared to that in control rats treated with either irrelevant rabbit IgG or PBS. Moreover, when given up to the 105th day of age, these doses of anti-IFN gamma Abs exerted comparable preventive effects regardless of whether application started as early as within 24 h after birth or at the end of the prediabetic period (e.g. 70/75 days). In contrast, under none of the above experimental conditions did larger doses of anti-IFN gamma Ab (500 micrograms or 1 mg/week) exert antidiabetogenic effects in the BB rats. Apparently, this was due to the exuberant production of neutralizing Abs elicited by the large amount of the xenogeneic Ab injected. At histoimmunological analyses, the BB rats treated with 200 micrograms/ week anti-IFN gamma Abs from 30-80 days of age exhibited a milder insulitic process along with diminished spleen frequency of activated lymphoid cells (MHC class II and interleukin-2 receptor positive). Taken together, these results provide further in vivo evidence for the central pathogenic role of IFN gamma in BB rat IDDM and anticipate the usefulness of specific IFN gamma inhibitors in the prevention of the disease in the clinical setting. Defining novel and less immunogenic forms of specific IFN gamma inhibitors than xenogeneic Abs is important for improving the efficiency of anti-IFN gamma-oriented approaches.
OBJECTIVE: Oxidative stress is considered a hallmark of atherosclerosis. In particular, the superoxide-generating type 1 NADPH oxidase (NOX1) has been shown to be induced and play a pivotal role in early phases of mouse models of atherosclerosis and in the context of diabetes mellitus. Here, we inv
estigated the role of the most abundant type 4 isoform (NOX4) in human and mouse advanced atherosclerosis. APPROACH AND RESULTS: Plaques of patients with cardiovascular events or established diabetes mellitus showed a surprising reduction in expression of the most abundant but hydrogen peroxide (H2O2)-generating type 4 isoform (Nox4), whereas Nox1 mRNA was elevated, when compared with respective controls. As these data suggested that NOX4-derived reactive oxygen species may convey a surprisingly protective effect during plaque progression, we examined a mouse model of accelerated and advanced diabetic atherosclerosis, the streptozotocin-treated ApoE(-/-) mouse, with (NOX4(-/-)) and without genetic deletion of Nox4. Similar to the human data, advanced versus early plaques of wild-type mice showed reduced Nox4 mRNA expression. Consistent with a rather protective role of NOX4-derived reactive oxygen species, NOX4(-/-) mice showed increased atherosclerosis when compared with wild-type mice. Deleting NOX4 was associated with reduced H2O2 forming activity and attenuation of the proinflammatory markers, monocyte chemotratic protein-1, interleukin-1beta, and tumor necrosis factor-alpha, as well as vascular macrophage accumulation. Furthermore, there was a greater accumulation of fibrillar collagen fibres within the vascular wall and plaque in diabetic Nox4(-/-)ApoE(-/-) mice, indicative of plaque remodeling. These data could be replicated in human aortic endothelial cells in vitro, where Nox4 overexpression increased H2O2 and reduced the expression of pro-oxidants and profibrotic markers. Interestingly, Nox4 levels inversely correlated with Nox2 gene and protein levels. Although NOX2 is not constitutively active unlike NOX4 and forms rather superoxide, this opens up the possibility that at least some effects of NOX4 deletion are mediated by NOX2 activation. CONCLUSIONS: Thus, the appearance of reactive oxygen species in atherosclerosis is apparently not always a nondesirable oxidative stress, but can also have protective effects. Both in humans and in mouse, the H2O2-forming NOX4, unlike the superoxide-forming NOX1, can act as a negative modulator of inflammation and remodeling and convey atheroprotection. These results have implications on how to judge reactive oxygen species formation in cardiovascular disease and need to be considered in the development of NOX inhibitory drugs.
Arthus MF, etal., J Am Soc Nephrol. 2000 Jun;11(6):1044-54.
X-linked nephrogenic diabetes insipidus (NDI) is a rare disease caused by mutations in the arginine vasopressin receptor 2 gene (AVPR2). Thirty-three novel AVPR2 mutations were identified in 62 families that were not included in our previous studies. This study describes the diversity of mutations o
bserved in a total of 117 families, the number of affected people at the time of diagnosis, skewed X chromosome inactivation in severely affected females, the inferred parental origin of de novo mutations, and it provides estimates of incidence. Among 117 families, there were 82 different putative disease-causing mutations. Based on haplotype analysis, it can be inferred that when the same AVPR2 mutation is identified in different families that were not known to be related, the mutations most likely arose independently. More than half of the families had only one affected male; two families presented with a severely affected female and no family history of NDI. A de novo mutation arose during oogenesis in the mother in 20% of isolated cases. The estimate of about 8.8 per million male live births of the incidence of X-linked NDI in the province of Quebec, Canada may be representative of the general population except in Nova Scotia and New Brunswick, where the incidence is more than six times higher. Documentation of the diversity of mutations will assist in revealing the full spectrum of clinical variation. Discussion of genetic and population genetic aspects of X-linked NDI may contribute to early diagnosis and treatment.
Wang M, etal., Birth Defects Res A Clin Mol Teratol. 2015 Dec;103(12):1021-7. doi: 10.1002/bdra.23422. Epub 2015 Sep 14.
BACKGROUND: Neural tube defects (NTDs) are among the most common congenital defects affecting approximately 1 in 1000 live births in North America. Their etiology is complex including environmental and genetic factors. Defects in the planar cell polarity (PCP) signaling pathway have been strongly as
sociated with NTDs in animal models and human cohorts. Protein tyrosine kinase 7 (Ptk7) was shown to cause a very severe form of NTDs called craniorachischisis in a mouse model and genetically interacts with a core PCP member Vangl2 where double heterozygotes suffer from spina bifida. In this study, we examined the role of PTK7 in human NTDs to determine whether variants at this gene predispose to these defects. METHODS: We sequenced the coding region and the exon-intron junctions of PTK7 in a cohort of 473 patients affected with various forms of open and closed NTDs. Novel and rare variants(<1%) were genotyped in a cohort of 473 individuals. Their pathogenic effect was predicted in silico and functionally in an overexpression assay in a well-established zebrafish model. RESULTS: We identified in our cohort 6 rare variants, 3 of which were absent in public databases. One variant, p.Gly348Ser, acted as a hypermorph when overexpressed in the zebrafish model. CONCLUSION: We detected potentially pathogenic PTK7 variants in 1.1% of our NTD cohort. Our findings implicate PTK7 as a risk factor for NTDs and provide additional evidence for a pathogenic role of PCP signaling in these malformations.
BACKGROUND: Impaired signaling in the IFN-γ/IL-12 pathway causes susceptibility to severe disseminated infections with mycobacteria and dimorphic yeasts. Dominant gain-of-function mutations in signal transducer and activator of transcription 1 (STAT1) have been associated with chron
ic mucocutaneous candidiasis. OBJECTIVE: We sought to identify the molecular defect in patients with disseminated dimorphic yeast infections. METHODS: PBMCs, EBV-transformed B cells, and transfected U3A cell lines were studied for IFN-γ/IL-12 pathway function. STAT1 was sequenced in probands and available relatives. Interferon-induced STAT1 phosphorylation, transcriptional responses, protein-protein interactions, target gene activation, and function were investigated. RESULTS: We identified 5 patients with disseminated Coccidioides immitis or Histoplasma capsulatum with heterozygous missense mutations in the STAT1 coiled-coil or DNA-binding domains. These are dominant gain-of-function mutations causing enhanced STAT1 phosphorylation, delayed dephosphorylation, enhanced DNA binding and transactivation, and enhanced interaction with protein inhibitor of activated STAT1. The mutations caused enhanced IFN-γ-induced gene expression, but we found impaired responses to IFN-γ restimulation. CONCLUSION: Gain-of-function mutations in STAT1 predispose to invasive, severe, disseminated dimorphic yeast infections, likely through aberrant regulation of IFN-γ-mediated inflammation.
La Russa A, etal., J Neuroimmunol. 2010 Aug 25;225(1-2):175-9. doi: 10.1016/j.jneuroim.2010.04.016. Epub 2010 May 14.
To investigate the role of the matrix metalloproteinase-9 gene (MMP-9) in multiple sclerosis (MS), we analyzed the functional -1562C/T and -90 (CA)(n) repeat polymorphisms in 243 Italian patients with MS and 173 healthy controls. A significant increase of the -1562T allele carriers was found in pati
A number of tumors exhibit an altered expression of sirtuins, including NAD+-dependent histone deacetylase silent information regulator 1 (SIRT1) that may act as a tumor suppressor or tumor promoter mainly depending on the tumor types. For instance, in breast cancer cells SIRT1 was shown to exert an
essential role toward the oncogenic signaling mediated by the estrogen receptor-alpha (ERalpha). In accordance with these findings, the suppression of SIRT1 led to the inhibition of the transduction pathway triggered by ERalpha. As the regulation of SIRT1 has not been investigated in cancer cells lacking ER, in the present study we ascertained the expression and function of SIRT1 by estrogens in ER-negative breast cancer cells and cancer-associated fibroblasts obtained from breast cancer patients. Our results show that 17beta-estradiol (E2) and the selective ligand of GPER, namely G-1, induce the expression of SIRT1 through GPER and the subsequent activation of the EGFR/ERK/c-fos/AP-1 transduction pathway. Moreover, we demonstrate that SIRT1 is involved in the pro-survival effects elicited by E2 through GPER, like the prevention of cell cycle arrest and cell death induced by the DNA damaging agent etoposide. Interestingly, the aforementioned actions of estrogens were abolished silencing GPER or SIRT1, as well as using the SIRT1 inhibitor Sirtinol. In addition, we provide evidence regarding the involvement of SIRT1 in tumor growth stimulated by GPER ligands in breast cancer cells and xenograft models. Altogether, our data suggest that SIRT1 may be included in the transduction network activated by estrogens through GPER toward the breast cancer progression.
OBJECTIVE: The aim of the present study was to evaluate serum soluble interleukin-1 receptor antagonist (sIL-1RA) concentration and its relationship with the degree of cigarette smoking in patients with Graves' ophthalmopathy (GO). DESIGN AND SUBJECTS: Twenty-two consecutive GO patients (20 women, t
wo men; age range 25-68 years, mean 48 years; 12 smokers, 10 non-smokers) submitted to IV glucocorticoid pulses over a 3-month period. MEASUREMENTS: sIL-1RA levels were measured by an immunoenzymatic assay (sensitivity, 4 ng/l; normal range, 50-290 ng/l) before glucocorticoid treatment, after two months of therapy, and 3 months after drug withdrawal. RESULTS: Thirteen patients responded to treatment (59%; five smokers and eight non-smokers), nine were non-responders (41%; seven smokers and two non-smokers). Baseline median sIL-1RA concentration did not differ in smokers and non-smokers (222 and 173 ng/l, respectively; P = 0.69). Likewise, no significant differences were found between the two groups during treatment (537 and 389 ng/l, respectively; P = 0.28); sIL-1RA concentration after treatment was higher in smokers (258 vs. 94 ng/l; P = 0.02). There was no correlation between basal sIL-1RA levels and the degree of cigarette smoking. Likewise, there was no difference in sIL-1RA levels in responders and non-responders, either at baseline (186 vs. 216 ng/l; P = 0.83), during or after treatment. CONCLUSION: Our study suggests that circulating soluble interleukin-1 receptor antagonist levels, both at baseline and during glucocorticoid treatment, are neither influenced by cigarette smoking nor predictive of subsequent response to glucocorticoid treatment.
The Vps10p family member sortilin is involved in various cell processes, including protein trafficking. Here we found that sortilin is expressed in thyroid epithelial cells (thyrocytes) in a TSH-dependent manner, that the hormone precursor thyroglobulin (Tg) is a high-affinity sortilin ligand, and t
hat binding to sortilin occurs after Tg endocytosis, resulting in Tg recycling. Sortilin was found to be expressed intracellularly in thyrocytes, as observed in mouse, human, and rat thyroid as well as in FRTL-5 cells. Sortilin expression was demonstrated to be TSH dependent, both in FRTL-5 cells and in mice treated with methimazole and perchlorate. Plasmon resonance binding assays showed that Tg binds to sortilin in a concentration-dependent manner and with high affinity, with Kd values that paralleled the hormone content of Tg. In addition, we found that Tg and sortilin interact in vivo and in cultured cells, as observed by immunoprecipitation, in mouse thyroid extracts and in COS-7 cells transiently cotransfected with sortilin and Tg. After incubation of FRTL-5 cells with exogenous, labeled Tg, sortilin and Tg interacted intracellularly, presumably within the endocytic pathway, as observed by immunofluorescence and immunoelectron microscopy, the latter technique showing some degree of Tg recycling. This was confirmed in FRTL-5 cells in which Tg recycling was reduced by silencing of the sortilin gene and in CHO cells transfected with sortilin in which recycling was increased. Our findings provide a novel pathway of Tg trafficking and a novel function of sortilin in the thyroid gland, the functional impact of which remains to be established.
Toriyama M, etal., Nat Genet. 2016 Jun;48(6):648-56. doi: 10.1038/ng.3558. Epub 2016 May 9.
Cilia use microtubule-based intraflagellar transport (IFT) to organize intercellular signaling. Ciliopathies are a spectrum of human diseases resulting from defects in cilia structure or function. The mechanisms regulating the assembly of ciliary multiprotein complexes and the transport of these com
plexes to the base of cilia remain largely unknown. Combining proteomics, in vivo imaging and genetic analysis of proteins linked to planar cell polarity (Inturned, Fuzzy and Wdpcp), we identified and characterized a new genetic module, which we term CPLANE (ciliogenesis and planar polarity effector), and an extensive associated protein network. CPLANE proteins physically and functionally interact with the poorly understood ciliopathy-associated protein Jbts17 at basal bodies, where they act to recruit a specific subset of IFT-A proteins. In the absence of CPLANE, defective IFT-A particles enter the axoneme and IFT-B trafficking is severely perturbed. Accordingly, mutation of CPLANE genes elicits specific ciliopathy phenotypes in mouse models and is associated with ciliopathies in human patients.
Ramos AV, etal., BMC Med Genet. 2012 Nov 7;13:101. doi: 10.1186/1471-2350-13-101.
BACKGROUND: Obesity has become a common human disorder associated with significant morbidity and mortality and adverse effects on quality of life. Sequence variants in two candidate genes, FTO and UCP-1, have been reported to be overrepresented in obese Caucasian population. The associati
on of these genes polymorphisms with the obesity phenotype in a multiethnic group such as the Brazilian population has not been previously reported. METHODS: To assess the putative contribution of both FTO and UCP-1 to body mass index (BMI) and cardiovascular risk we genotyped SNPs rs9939609 (FTO) and rs6536991, rs22705565 and rs12502572 (UCP-1) from 126 morbidly obese subjects (BMI 42.9 ± 5.6 kg/m2, mean ± SE) and 113 normal-weight ethnically matched controls (BMI 22.6 ± 3.5 kg/m2, mean ± SE). Waist circumference, blood pressure, glucose and serum lipids were also measured. Each sample was also genotyped for 40 biallelic short insertion/deletion polymorphism (indels) for ethnic assignment and to estimate the proportion of European, African and Amerindian biogeographical ancestry in the Brazilian population. RESULTS: Cases did not differ from controls in the proportions of genomic ancestry. The FTO SNP rs9939609 and UCP-1 SNP rs6536991 were significantly associated with BMI (p= 0.04 and p<0.0001 respectively). An allele dose dependent tendency was observed for BMI for rs6536991 sample of controls. No other significant associations between any SNP and hypertension, hyperlipidemia and diabetes were noted after correction for BMI and no significant synergistic effect between FTO and UCP-1 SNPs with obesity were noted. There was not an association between rs9939609 (FTO) and rs6536991 (UCP-1) in with maximum weight loss after 1 year in 94 obese patients who underwent bariatric surgery. CONCLUSION: Our data are consistent with FTO rs9939609 and UCP-1 rs6536991 common variants as contributors to obesity in the Brazilian population.
BACKGROUND: Evidences suggest that GAB2 and BDNF genes may be associated with Alzheimer's disease (AD). We aimed to investigate the GAB2 rs2373115 and BDNF rs6265 polymorphisms and the risk of AD in a Brazilian sample. METHODS: 269 AD patients and 114 controls were genotyped with Real-time PCR. Mult
ifactor dimensionality reduction (MDR) was employed to explore the effects of gene-gene interactions. RESULTS: GAB2 and BDNF were not associated with AD in our sample. Nevertheless BDNF Val allele (rs6265) presented a synergic association with the APOE epsilon4 allele. A multiple logistic regression demonstrated that the APOE epsilon4 allele and years of education were the best predictors for AD. In epsilon4 non-carriers sex, education and hypertension were independently correlated with AD, while in epsilon4 carriers we did not observe any association. The findings were further confirmed by bootstrapping method. CONCLUSIONS: Our data suggest that the interaction of BDNF and APOE has significant effect on AD. Moreover in absence of epsilon4, female sex, low level of education and hypertension are independently associated with AD. Interventions aimed to prevent AD should focus on these factors and also taking into account the APOE alleles.
Scrima M, etal., Am J Pathol. 2012 Mar;180(3):1202-1214. doi: 10.1016/j.ajpath.2011.11.038. Epub 2012 Jan 13.
The aim of the present work was to identify protein tyrosine phosphatases (PTPs) as novel, candidate tumor suppressor genes in lung cancer. Among the 38 PTPs in the human genome that show specificity for phosphotyrosine, we identified six PTPs by quantitative RT-PCR whose mRNA expression levels were
significantly down-regulated in lung cancer-derived cell lines (ie, PTPRE, PTPRF, PTPRU, PTPRK, PTPRD, and PTPN13). After validation in primary samples of non-small cell lung cancer (NSCLC), we selected PTPN13 for further studies. The results presented here demonstrate that PTPN13 is a candidate tumor suppressor gene that is frequently inactivated in NSCLC through the loss of either mRNA and protein expression (64/87, 73%) or somatic mutation (approximately 8%). Loss of PTPN13 expression was apparently due to the loss of one or both copies of the PTPN13 locus at 4q (approximately 26% double deletion and approximately 37% single deletion) but not to promoter methylation. Finally, the manipulation of PTPN13 expression in lung cancer cells (ie, NCI-H292, A549) demonstrated that PTPN13 negatively regulates anchorage-dependent and anchorage-independent growth in vitro and restrains tumorigenicity in vivo, possibly through the control of the tyrosine phosphorylation of both EGFR and HER2. In conclusion, the expression screening of PTPs in lung cancer reported here has identified PTPN13 as a novel candidate tumor suppressor in NSCLC whose loss increases signaling from epidermal growth factor receptor and HER2 tyrosine kinase receptors.
BACKGROUND: Abdominal obesity (AO) is a common modifiable risk factor for certain non-communicable diseases associated with enhanced oxidative stress (OS). The objective of this work was to investigate whether the interaction between antioxidant vitamin intake and OS-related polymorphisms modulates
gene-associated anthropometry in a Spanish population. METHODS: A total of 246 subjects with AO, and 492 age and gender matched non-AO subjects were included in the study. Anthropometric, biochemical, and OS parameters, and antioxidant dietary intake data were assessed using validated procedures. DNA from white blood cells was isolated and the genotype of seven polymorphisms from genes involved in OS (pro-oxidant and antioxidant) were analyzed using the SNPlex system. The effects of the c.-793T > C polymorphism on promoter activity and thus thioredoxin (TXN) activity were examined using reporter assays. RESULTS: The AO group had higher 8-Oxo-2'-deoxyguanosine levels and took in less vitamin A and vitamin E compared to the non-AO group. Logistic regression analysis revealed that the rs2301241 polymorphism in TXN and rs740603 in catechol-O-methyltransferase (COMT) were associated with waist circumference (WC) and AO. Moreover, these polymorphisms were more strongly associated with variations in WC in subjects with low vitamin E intakes. A promoter assay revealed that the T to C conversion at c.-793 (rs2301241) induced a more than two fold increase in reporter gene expression. CONCLUSIONS: WC is associated both with dietary vitamin E intake and genetic variants of TXN and COMT suggesting that existence of a complex nutrigenetic pathway that involves regulation of AO.
BACKGROUND & AIMS: We tested the putative association of the rs58542926 variant of TM6SF2, a recently described genetic determinant of nonalcoholic fatty liver disease, with steatosis and fibrosis in genotype 1(G1) chronic hepatitis C(CHC) patients. METHODS: A total of 694 consecutively biopsied Cau
casian G1 CHC patients were genotyped for TM6SF2 rs58542926, IL28B rs12979860 and PNPLA3 rs738409. Steatosis was classified as absent (<5%), mild-moderate(5-29%) and severe(>/=30%), Fibrosis was considered severe if=F3-F4. RESULTS: Carriers of TM6SF2 rs58542926 (6.3% of patients) exhibited lower serum levels of cholesterol (P = 0.04) and triglycerides (P = 0.01), but a similar distribution of steatosis severity (P = 0.63), compared to noncarriers. Prevalence and severity of steatosis were reduced in IL28B C allele carriers (P = 0.005) and elevated in PNPLA3 G allele carriers (P < 0.001). After adjustment for age, gender, body mass index and homoeostasis model assessment score, steatosis severity was independently associated with IL28B rs12979860 (odds ratio [OR] 0.69, 95% confidence interval [CI] 0.55-0.86, P = 0.001) and PNPLA3 rs738409 (OR 1.84, 95% CI 1.46-2.83, P < 0.001), but not TM6SF2 rs58542926 (OR 1.48, 95% CI 0.82-2.69, P = 0.19). Variants of TM6SF2 (30.9% vs. 25%, P = 0.40), IL28B and PNPLA3 were not directly associated with fibrosis severity, although variants of IL28B and PNPLA3 promoted steatosis (OR 1.36, 95% CI 1.06-1.75, P = 0.01) that in turn is associated with severe fibrosis. CONCLUSIONS: In G1 CHC patients, TM6SF2 rs58542926 does not affect the histological severity of liver damage. However, IL28B rs12979860 and PNPLA3 rs738409 modify steatosis.
Corns LF, etal., J Neurosci. 2016 Jan 13;36(2):336-49. doi: 10.1523/JNEUROSCI.2439-15.2016.
The transduction of sound into electrical signals depends on mechanically sensitive ion channels in the stereociliary bundle. The molecular composition of this mechanoelectrical transducer (MET) channel is not yet known. Transmembrane channel-like protein isoforms 1 (TMC1) and 2 (TMC2) have been pr
oposed to form part of the MET channel, although their exact roles are still unclear. Using Beethoven (Tmc1(Bth/Bth)) mice, which have an M412K point mutation in TMC1 that adds a positive charge, we found that Ca(2+) permeability and conductance of the MET channel of outer hair cells (OHCs) were reduced. Tmc1(Bth/Bth) OHCs were also less sensitive to block by the permeant MET channel blocker dihydrostreptomycin, whether applied extracellularly or intracellularly. These findings suggest that the amino acid that is mutated in Bth is situated at or near the negatively charged binding site for dihydrostreptomycin within the permeation pore of the channel. We also found that the Ca(2+) dependence of the operating range of the MET channel was altered by the M412K mutation. Depolarization did not increase the resting open probability of the MET current of Tmc1(Bth/Bth) OHCs, whereas raising the intracellular concentration of the Ca(2+) chelator BAPTA caused smaller increases in resting open probability in Bth mutant OHCs than in wild-type control cells. We propose that these observations can be explained by the reduced Ca(2+) permeability of the mutated MET channel indirectly causing the Ca(2+) sensor for adaptation, at or near the intracellular face of the MET channel, to become more sensitive to Ca(2+) influx as a compensatory mechanism. SIGNIFICANCE STATEMENT: In the auditory system, the hair cells convert sound-induced mechanical movement of the hair bundles atop these cells into electrical signals through the opening of mechanically gated ion channels at the tips of the bundles. Although the nature of these mechanoelectrical transducer (MET) channels is still unclear, recent studies implicate transmembrane channel-like protein isoform 1 (TMC1) channels in the mammalian cochlea. Using a mutant mouse model (Beethoven) for progressive hearing loss in humans (DFNA36), which harbors a point mutation in the Tmc1 gene, we show that this mutation affects the MET channel pore, reducing its Ca(2+) permeability and its affinity for the permeant blocker dihydrostreptomycin. A number of phenomena that we ascribe to Ca(2+)-dependent adaptation appear stronger, in compensation for the reduced Ca(2+) entry.
Solari E, etal., Am J Physiol Heart Circ Physiol. 2020 Aug 1;319(2):H507-H518. doi: 10.1152/ajpheart.00175.2020. Epub 2020 Jul 24.
The lymphatic system drains and propels lymph by extrinsic and intrinsic mechanisms. Intrinsic propulsion depends upon spontaneous rhythmic contractions of lymphatic muscles in the vessel walls and is critically affected by changes in the surrounding tissue like osmolarity and temperature. Lymphatic
s of the diaphragm display a steep change in contraction frequency in response to changes in temperature, and this, in turn, affects lymph flow. In the present work, we demonstrated in an ex vivo diaphragmatic tissue rat model that diaphragmatic lymphatics express transient receptor potential channels of the vanilloid 4 subfamily (TRPV4) and that their blockade by both the nonselective antagonist Ruthenium Red and the selective antagonist HC-067047 abolished the response of lymphatics to temperature changes. Moreover, the selective activation of TRPV4 channels by means of GSK1016790A mirrored the behavior of vessels exposed to increasing temperatures, pointing out the critical role played by these channels in sensing the temperature of the lymphatic vessels' environment and thus inducing a change in contraction frequency and lymph flow.NEW & NOTEWORTHY The present work addresses the putative receptor system that enables diaphragmatic lymphatics to change intrinsic contraction frequency and thus lymph flow according to the changes in temperature of the surrounding environment, showing that this role can be sustained by TRPV4 channels alone.
Molinaro A, etal., J Bone Miner Res. 2015 May;30(5):906-12. doi: 10.1002/jbmr.2408.
Hypocalcemia and hyperphosphatemia because of resistance toward parathyroid hormone (PTH) in the proximal renal tubules are the most prominent abnormalities in patients affected by pseudohypoparathyroidism type Ib (PHP-Ib). In this rare disorder, which is caused by GNAS methylation changes, resista
nce can occur toward other hormones, such as thyroid-stimulating hormone (TSH), that mediate their actions through G protein-coupled receptors. However, these additional laboratory abnormalities are usually not recognized until PTH-resistant hypocalcemia becomes clinically apparent. We now describe four pediatric patients, first diagnosed with subclinical or overt hypothyroidism between the ages of 0.2 and 15 years, who developed overt PTH-resistance 3 to 20 years later. Although anti-thyroperoxidase (anti-TPO) antibodies provided a plausible explanation for hypothyroidism in one of these patients, this and two other patients revealed broad epigenetic GNAS abnormalities, which included loss of methylation (LOM) at exons AS, XL, and A/B, and gain of methylation at exon NESP55; ie, findings consistent with PHP-Ib. LOM at GNAS exon A/B alone led in the fourth patient to the identification of a maternally inherited 3-kb STX16 deletion, a well-established cause of autosomal dominant PHP-Ib. Although GNAS methylation changes were not detected in additional pediatric and adult patients with subclinical hypothyroidism (23 pediatric and 39 adult cases), hypothyroidism can obviously be the initial finding in PHP-Ib patients. One should therefore consider measuring PTH, along with calcium and phosphate, in patients with unexplained hypothyroidism for extended periods of time to avoid hypocalcemia and associated clinical complications.
Rett syndrome (RTT) is a severe neurodevelopmental disorder affecting almost exclusively females. The Hanefeld variant, or early-onset seizure variant, has been associated with mutations in CDKL5 gene. AIMS: In recent years more than 60 patients with mutations in the CDKL5 gene have been described
in the literature, but the cardiorespiratory phenotype has not been reported. Our aim is to describe clinical and autonomic features of these girls. METHODS: 10 girls with CDKL5 mutations and a diagnosis of Hanefeld variant have been evaluated on axiological and clinical aspects. In all subjects an evaluation of the autonomic system was performed using the Neuroscope. RESULTS: Common features were gaze avoidance, repetitive head movements and hand stereotypies. The autonomic evaluation disclosed eight cases with the Forceful breather cardiorespiratory phenotype and two cases with the Apneustic breather phenotype. CONCLUSIONS: The clinical picture remains within the RTT spectrum but some symptoms are more pronounced in addition to the very early onset of seizures. The cardiorespiratory phenotype was dominated by Forceful breathers, while Feeble breathers were not found, differently from the general Rett population, suggesting a specific behavioral and cardiorespiratory phenotype of the RTT the Hanefeld variant.
Buniello A, etal., EMBO Mol Med. 2016 Feb 8;8(3):191-207. doi: 10.15252/emmm.201505523.
WBP2 encodes the WW domain-binding protein 2 that acts as a transcriptional coactivator for estrogen receptor alpha (ESR1) and progesterone receptor (PGR). We reported that the loss of Wbp2 expression leads to progressive high-frequency hearing loss in mouse, as well as in two deaf children, each c
arrying two different variants in the WBP2 gene. The earliest abnormality we detect in Wbp2-deficient mice is a primary defect at inner hair cell afferent synapses. This study defines a new gene involved in the molecular pathway linking hearing impairment to hormonal signalling and provides new therapeutic targets.
Kim C, etal., Diabet Med. 2016 Jan;33(1):32-8. doi: 10.1111/dme.12799. Epub 2015 May 29.
AIM: To examine concentrations of biomarkers (adiponectin, C-reactive protein, fibrinogen and tissue plasminogen-activator antigen) associated with glucose homeostasis and diabetes risk by history of gestational diabetes (GDM). METHODS: We conducted a secondary analysis of the Diabetes Prevention P
rogram, a randomized trial of lifestyle intervention or metformin for diabetes prevention. At baseline, participants were overweight and had impaired glucose tolerance. Biomarkers at baseline and 1 year after enrolment were compared between parous women with (n = 350) and without histories of GDM (n = 1466). Cox proportional hazard models evaluated whether history of GDM was associated with diabetes risk, after adjustment for baseline biomarker levels as well as for change in biomarker levels, demographic factors and anthropometrics. RESULTS: At baseline, women with histories of GDM had lower adiponectin (7.5 mug/ml vs. 8.7 mug/ml; p < 0.0001) and greater log C-reactive protein (-0.90 mg/l vs. -0.78 mg/l, p = 0.04) levels than women without histories of GDM, but these associations did not persist after adjustment for demographic factors. Fibrinogen and tissue plasminogen-activator antigen were similar between women with and without histories of GDM. Women with and without histories of GDM had a similar pattern of changes in biomarkers within randomization arm. Adjustment for age, race/ethnicity, baseline weight, change in weight, baseline biomarker level and change in biomarker level did not significantly alter the association between history of GDM, and diabetes risk. CONCLUSIONS: Among women with impaired glucose tolerance, biomarkers in women with and without histories of GDM are similar and respond similarly to lifestyle changes and metformin. Adjustment for biomarker levels did not explain the higher risk of diabetes observed in women with histories of GDM.
West NA, etal., Diabetes Care. 2009 Jan;32(1):175-80. Epub 2008 Oct 22.
OBJECTIVE: To compare cardiovascular disease (CVD) risk factors among recently diagnosed youth with type 2 diabetes and nondiabetic youth and investigate whether demographic, behavioral, or metabolic factors might account for observed differences. RESEARCH DESIGN AND METHODS: Data from 106 type 2 di
abetic and 189 nondiabetic multiethnic youth, aged 10-22 years, were analyzed. Prevalence of CVD risk factors were age and race/ethnicity adjusted using direct standardization. Multiple linear regression models were sequentially adjusted for demographic, behavioral (dietary saturated fat intake and physical activity), and metabolic (body adiposity and glycemia) factors to explore possible mechanisms associated with differences in CVD risk factors between the case and control groups. RESULTS: Compared with control subjects, youth with type 2 diabetes had a higher prevalence of elevated blood pressure, obesity, large waist circumference, low HDL cholesterol, high triglycerides, and high albumin-to-creatinine ratio (P < 0.05 for each risk factor). Type 2 diabetic youth also had higher levels of apolipoprotein B, fibrinogen, interleukin (IL)-6, C-reactive protein, and leptin; lower adiponectin levels; and denser LDL particles (P < 0.05 for each risk factor). Adjustment for BMI, waist circumference, and A1C substantially attenuated differences in the CVD risk factors between the case/control groups, except for fibrinogen and IL-6, which remained significantly higher in type 2 diabetic youth. CONCLUSIONS: Compared with control youth, type 2 diabetic youth have a less favorable CVD risk factor profile. Adiposity and glycemia are important contributors to differences in CVD risk profiles among type 2 diabetic and control youth. Inflammatory and prothrombotic factors may also play an important role.
BACKGROUND: Phospholipid transfer protein (PLTP) plays an important role in HDL particle metabolism and may modulate hepatic secretion of apolipoprotein B-containing lipoproteins. However, whether PLTP might participate directly in human atherosclerotic lesion formation is unknown. METHODS AND RESUL
TS: The cellular and extracellular distributions of PLTP were determined in normal and atherosclerotic human coronary lesions with a monoclonal antibody to human PLTP. Cell types (smooth muscle cells [SMCs] or macrophages), apolipoproteins (apoA-I, apoB, and apoE), and extracellular matrix proteoglycans (biglycan and versican) were identified on adjacent sections with monospecific antibodies. Minimal extracellular PLTP was detected in nonatherosclerotic coronary arteries, but extracellular and cellular PLTP immunostaining was widespread in atherosclerotic lesions. PLTP was detected in foam cell SMCs and in foam cell macrophages, which suggests that cellular cholesterol accumulation might increase PLTP expression in both cell types. This was confirmed by in vitro studies demonstrating that cholesterol loading of macrophages leads to 2- to 3-fold increases in PLTP steady-state mRNA levels, protein expression, and activity. PLTP also was detected in an extracellular distribution, colocalizing with apoA-I, apoB, apoE, and the vascular proteoglycan biglycan. In gel mobility shift assays, both active and inactive recombinant PLTP markedly increased HDL binding to biglycan, which suggests that PLTP may mediate lipoprotein binding to proteoglycans independent of its phospholipid transfer activity. CONCLUSIONS: PLTP is present in human atherosclerotic lesions, and its distribution suggests roles for PLTP in both cellular cholesterol metabolism and lipoprotein retention on extracellular matrix.
OBJECTIVES: Lipoprotein(a) [Lp(a)] is mainly similar in composition to LDL, but differs in having apolipoprotein (apo) (a) covalently linked to apoB-100. Our purpose was to examine the individual metabolism of apo(a) and apoB-100 within plasma Lp(a). MATERIALS AND METHODS: The kinetics of apo(a) and
apoB-100 in plasma Lp(a) were assessed in four men with dyslipidemia [Lp(a) concentration: 8.9-124.7nmol/L]. All subjects received a primed constant infusion of [5,5,5-(2)H3] L-leucine while in the constantly fed state. Lp(a) was immunoprecipitated directly from whole plasma; apo(a) and apoB-100 were separated by gel electrophoresis; and isotopic enrichment was determined by gas chromatography/mass spectrometry. RESULTS: Multicompartmental modeling analysis indicated that the median fractional catabolic rates of apo(a) and apoB-100 within Lp(a) were significantly different at 0.104 and 0.263 pools/day, respectively (P=0.04). The median Lp(a) apo(a) production rate at 0.248nmol/kg.day(-1) was significantly lower than that of Lp(a) apoB-100 at 0.514nmol/kg.day(-1) (P=0.03). CONCLUSION: Our data indicate that apo(a) has a plasma residence time (11days) that is more than twice as long as that of apoB-100 (4days) within Lp(a), supporting the concept that apo(a) and apoB-100 within plasma Lp(a) are not catabolized from the bloodstream as a unit in humans in the fed state.
Ansseau E, etal., PLoS One. 2009 Oct 15;4(10):e7482. doi: 10.1371/journal.pone.0007482.
Facioscapulohumeral muscular dystrophy (FSHD) is a dominant disease linked to contractions of the D4Z4 repeat array in 4q35. We have previously identified a double homeobox gene (DUX4) within each D4Z4 unit that encodes a transcription factor expressed in FSHD but not control myoblasts. DUX4 and its
target genes contribute to the global dysregulation of gene expression observed in FSHD. We have now characterized the homologous DUX4c gene mapped 42 kb centromeric of the D4Z4 repeat array. It encodes a 47-kDa protein with a double homeodomain identical to DUX4 but divergent in the carboxyl-terminal region. DUX4c was detected in primary myoblast extracts by Western blot with a specific antiserum, and was induced upon differentiation. The protein was increased about 2-fold in FSHD versus control myotubes but reached 2-10-fold induction in FSHD muscle biopsies. We have shown by Western blot and by a DNA-binding assay that DUX4c over-expression induced the MYF5 myogenic regulator and its DNA-binding activity. DUX4c might stabilize the MYF5 protein as we detected their interaction by co-immunoprecipitation. In keeping with the known role of Myf5 in myoblast accumulation during mouse muscle regeneration DUX4c over-expression activated proliferation of human primary myoblasts and inhibited their differentiation. Altogether, these results suggested that DUX4c could be involved in muscle regeneration and that changes in its expression could contribute to the FSHD pathology.
OBJECTIVE: The effects of extended-release niacin (ERN; 1-2 g/d) on the metabolism of lipoprotein(a) (Lp(a)) and apolipoprotein (apo) B-100-containing lipoproteins were investigated in 11 statin-treated white men with type 2 diabetes mellitus in a randomized, crossover trial of 12-weeks duration. AP
PROACH AND RESULTS: The kinetics of Lp(a) and very low-density lipoprotein (VLDL), intermediate-density lipoprotein, and low-density lipoprotein (LDL) apoB-100 were determined following a standardized oral fat load (87% fat) using intravenous administration of D3-leucine, gas chromatography-mass spectrometry, and compartmental modeling. ERN significantly decreased fasting plasma total cholesterol, LDL cholesterol, and triglyceride concentrations. These effects were achieved without significant changes in body weight or insulin resistance. ERN significantly decreased plasma Lp(a) concentration (-26.5%) and the production rates of apo(a) (-41.5%) and Lp(a)-apoB-100 (-32.1%); the effect was greater in individuals with elevated Lp(a) concentration. ERN significantly decreased VLDL (-58.7%), intermediate-density lipoprotein (-33.6%), and LDL (-18.3%) apoB-100 concentrations and the corresponding production rates (VLDL, -49.8%; intermediate-density lipoprotein, -44.7%; LDL, -46.1%). The number of VLDL apoB-100 particles secreted increased in response to the oral fat load. Despite this, total VLDL apoB-100 production over the 10-hour postprandial period was significantly decreased with ERN (-21.9%). CONCLUSIONS: In statin-treated men with type 2 diabetes mellitus, ERN decreased plasma Lp(a) concentrations by decreasing the production of apo(a) and Lp(a)-apoB-100. ERN also decreased the concentrations of apoB-100-containing lipoproteins by decreasing VLDL production and the transport of these particles down the VLDL to LDL cascade. Our study provides further mechanistic insights into the lipid-regulating effects of ERN.
OBJECTIVE: The aim of this study was to examine the effects of acute exercise on insulin signaling in skeletal muscle of women with polycystic ovary syndrome (PCOS) and controls (CTRL). METHODS: Fifteen women with obesity and PCOS and 12 body mass index-matched CTRL participated in this study. Subj
ects performed a 40-min single bout of exercise. Muscle biopsies were performed before and 60 min after exercise. Selected proteins were assessed by Western blotting. RESULTS: CTRL, but not PCOS, showed a significant increase in PI3-k p85 and AS160 Thr 642 after a single bout of exercise (P = 0.018 and P = 0.018, respectively). Only PCOS showed an increase in Akt Thr 308 and AMPK phosphorylation after exercise (P = 0.018 and P = 0.018, respectively). Total GLUT4 expression was comparable between groups (P > 0.05). GLUT4 translocation tended to be significantly higher in both groups after exercise (PCOS: P = 0.093; CTRL: P = 0.091), with no significant difference between them (P > 0.05). CONCLUSIONS: A single bout of exercise elicited similar GLUT4 translocation in skeletal muscle of PCOS and CTRL, despite a slightly differential pattern of protein phosphorylation. The absence of impairment in GLUT4 translocation suggests that PCOS patients with obesity and insulin resistance may benefit from exercise training.
Pereira-da-Silva M, etal., Endocrinology. 2003 Nov;144(11):4831-40. Epub 2003 Jul 24.
Short-term cold exposure of homeothermic animals leads to higher thermogenesis and food consumption accompanied by weight loss. An analysis of cDNA-macroarray was employed to identify candidate mRNA species that encode proteins involved in thermogenic adaptation to cold. A cDNA-macroarray analysis,
confirmed by RT-PCR, immunoblot, and RIA, revealed that the hypothalamic expression of melanin-concentrating hormone (MCH) is enhanced by exposure of rats to cold environment. The blockade of hypothalamic MCH expression by antisense MCH oligonucleotide in cold-exposed rats promoted no changes in feeding behavior and body temperature. However, MCH blockade led to a significant drop in body weight, which was accompanied by decreased liver glycogen, increased relative body fat, increased absolute and relative interscapular brown adipose tissue mass, increased uncoupling protein 1 expression in brown adipose tissue, and increased consumption of lean body mass. Thus, increased hypothalamic MCH expression in rats exposed to cold may participate in the process that allows for efficient use of energy for heat production during thermogenic adaptation to cold.
Wensky AK, etal., J Immunol. 2005 Feb 1;174(3):1416-23.
Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the CNS initiated by autoreactive CD4(+) T cells. EAE classically presents with a progressive ascending paralysis and is a model of multiple sclerosis that recapitulates some aspects of the disease. In this report we descr
ibe a mouse strain that spontaneously develops a severe, nonclassical form of EAE with 100% incidence. The distinct clinical phenotype is marked initially by a slight head tilt, progressing to a severe head tilt, spinning, or a rotatory motion. Classical EAE spontaneously occurs in myelin basic protein (MBP)-specific TCR transgenic RAG-1(-/-) mice (referred to as T/R(-)), whereas nonclassical EAE spontaneously occurs in T/R(-) IFN-gamma(-/-) mice (T/R(-)gamma(-)). Thus, the TCR recognizes the same Ag (MBP) and uses identical TCR in both cases. The cellular infiltrate in nonclassical EAE is predominantly found in the brainstem and cerebellum, with very little inflammation in the spinal cord, which is primarily affected in classical disease. Importantly, depending on the genetic makeup and priming conditions of the MBP-specific T cells, nonclassical disease can occur in the presence of an inflammatory infiltrate with eosinophilic, neutrophilic, or monocytic characteristics. Finally, we believe that nonclassical spontaneous EAE could be a useful model for the study of some characteristics of multiple sclerosis not observed in classical EAE, such as the inflammatory responses in the brainstem and cerebellum that can cause vertigo.
Look AHEAD (Action for Health in Diabetes) is a randomized trial determining whether intensive lifestyle intervention (ILI) aimed at long-term weight loss and increased physical fitness reduces cardiovascular morbidity and mortality in overweight and obese individuals with type 2 diabetes compared t
o control (diabetes support and education, DSE). We investigated the correlates of N-terminal pro-brain natriuretic peptide (NT-proBNP), a biomarker associated with heart failure (HF) risk, in a subsample from 15 of 16 participating centers and tested the hypothesis that ILI decreased NT-proBNP levels. Baseline and 1-year blood samples were assayed for NT-proBNP in a random sample of 1,500 without, and all 628 with, self-reported baseline CVD (cardiovascular disease) (N = 2,128). Linear models were used to assess relationships that log-transformed NT-proBNP had with CVD risk factors at baseline and that 1-year changes in NT-proBNP had with intervention assignment. At baseline, the mean (s.d.) age, BMI, and hemoglobin A(1c) (HbA(1c)) were 59.6 (6.8) years, 36.0 kg/m(2) (5.8), and 7.2% (1.1), respectively. Baseline geometric mean NT-proBNP was not different by condition (ILI 53.3 vs. DSE 51.5, P = 0.45), was not associated with BMI, and was inversely associated with HbA(1c). At 1 year, ILI participants achieved an average weight loss of 8.3% compared to 0.7% in DSE. At 1 year, NT-proBNP levels increased to a greater extent in the intervention arm (ILI +21.3% vs. DSE +14.2%, P = 0.046). The increased NT-proBNP associated with ILI was correlated with changes in HbA(1c), BMI, and body composition. In conclusion, among overweight and obese persons with diabetes, an ILI that reduced weight was associated with an increased NT-proBNP.
We characterized the peroxidase mechanism of recombinant rat brain cytoglobin (Cygb) challenged by hydrogen peroxide, tert-butylhydroperoxide and by cumene hydroperoxide. The peroxidase mechanism of Cygb is similar to that of myoglobin. Cygb challenged by hydrogen peroxide is converted to a Fe4+ ox
oferryl pi cation, which is converted to Fe4+ oxoferryl and tyrosyl radical detected by direct continuous wave-electron paramagnetic resonance and by 3,5-dibromo-4-nitrosobenzene sulfonate spin trapping. When organic peroxides are used as substrates at initial reaction times, and given an excess of peroxide present, the EPR signals of the corresponding peroxyl radicals precede those of the direct tyrosyl radical. This result is consistent with the use of peroxide as a reducing agent for the recycling of Cygb high-valence species. Furthermore, we found that the Cygb oxidation by peroxides leads to the formation of amyloid fibrils. This result suggests that Cygb possibly participates in the development of degenerative diseases; our findings also support the possible biological role of Cygb related to peroxidase activity.
Li G, etal., Am J Respir Cell Mol Biol. 2014 Aug;51(2):210-22. doi: 10.1165/rcmb.2013-0353OC.
Claudin proteins are major constituents of epithelial and endothelial tight junctions (TJs) that regulate paracellular permeability to ions and solutes. Claudin 18, a member of the large claudin family, is highly expressed in lung alveolar epithelium. To elucidate the role of claudin 18 in alveolar
epithelial barrier function, we generated claudin 18 knockout (C18 KO) mice. C18 KO mice exhibited increased solute permeability and alveolar fluid clearance (AFC) compared with wild-type control mice. Increased AFC in C18 KO mice was associated with increased beta-adrenergic receptor signaling together with activation of cystic fibrosis transmembrane conductance regulator, higher epithelial sodium channel, and Na-K-ATPase (Na pump) activity and increased Na-K-ATPase beta1 subunit expression. Consistent with in vivo findings, C18 KO alveolar epithelial cell (AEC) monolayers exhibited lower transepithelial electrical resistance and increased solute and ion permeability with unchanged ion selectivity. Claudin 3 and claudin 4 expression was markedly increased in C18 KO mice, whereas claudin 5 expression was unchanged and occludin significantly decreased. Microarray analysis revealed changes in cytoskeleton-associated gene expression in C18 KO mice, consistent with observed F-actin cytoskeletal rearrangement in AEC monolayers. These findings demonstrate a crucial nonredundant role for claudin 18 in the regulation of alveolar epithelial TJ composition and permeability properties. Increased AFC in C18 KO mice identifies a role for claudin 18 in alveolar fluid homeostasis beyond its direct contributions to barrier properties that may, at least in part, compensate for increased permeability.
Lipoprotein lipase (LPL) is involved in regulation of fatty acid metabolism, and facilitates cellular uptake of lipoproteins, lipids and lipid-soluble vitamins. We evaluated LPL distribution in healthy and Alzheimer's disease (AD) brain tissue and its relative levels in cerebrospinal fluid. LPL immu
nostaining is widely present in different neuronal subgroups, microglia, astrocytes and oligodendroglia throughout cerebrum, cerebellum and spinal cord. LPL immunoreactivity is also present in leptomeninges, small blood vessels, choroid plexus and ependymal cells, Schwann cells associated with cranial nerves, and in anterior and posterior pituitary. In vitro studies have shown presence of secreted LPL in conditioned media of human cortical neuronal cell line (HCN2) and neuroblastoma cells (SK-N-SH), but not in media of cultured primary human astrocytes. LPL was present in cytoplasmic and nuclear fractions of neuronal cells and astrocytes in vitro. LPL immunoreactivity strongly associates with AD-related pathology, staining diffuse plaques, dystrophic and swollen neurites, possible Hirano bodies and activated glial cells. We observed no staining associated with neurofibrillary tangles or granulovacuolar degeneration. Granule cells of the dentate gyrus and the associated synaptic network showed significantly reduced staining in AD compared to control tissue. LPL was also reduced in AD CSF samples relative to those in controls.
Plasma levels of lipoprotein(a) [Lp(a)], an atherogenic particle, vary widely between individuals and are highly genetically determined. Whether Lp(a) is a positive acute-phase reactant is debated. The present study was designed to evaluate the impact of major inflammatory responses on plasma Lp(a)
levels. Plasma levels of C-reactive protein (CRP), low density lipoprotein cholesterol, Lp(a), and apolipoprotein(a) [apo(a)] fragments, as well as urinary apo(a), were measured serially in 9 patients admitted to the intensive care unit for sepsis and 4 patients with extensive burns. Sepsis and burns elicited a major increase in plasma CRP levels. In both conditions, plasma concentrations of Lp(a) declined abruptly and transiently in parallel with plasma low density lipoprotein cholesterol levels and closely mirrored plasma CRP levels. In 5 survivors, the nadir of plasma Lp(a) levels was 5- to 15-fold lower than levels 16 to 18 months after the study period. No change in plasma levels of apo(a) fragments or urinary apo(a) was noticed during the study period. Turnover studies in mice indicated that clearance of Lp(a) was retarded in lipopolysaccharide-treated animals. Taken together, these data demonstrate that Lp(a) behaves as a negative acute-phase reactant during major inflammatory response. Nongenetic factors have a major, acute, and unexpected impact on Lp(a) metabolism in burns and sepsis. Identification of these factors may provide new tools to lower elevated plasma Lp(a) levels.
Han CY, etal., J Clin Invest. 2016 Jan;126(1):266-81. doi: 10.1172/JCI83475. Epub 2015 Dec 7.
HDL from healthy humans and lean mice inhibits palmitate-induced adipocyte inflammation; however, the effect of the inflammatory state on the functional properties of HDL on adipocytes is unknown. Here, we found that HDL from mice injected with AgNO3 fails to inhibit palmitate-induced inflammation a
nd reduces cholesterol efflux from 3T3-L1 adipocytes. Moreover, HDL isolated from obese mice with moderate inflammation and humans with systemic lupus erythematosus had similar effects. Since serum amyloid A (SAA) concentrations in HDL increase with inflammation, we investigated whether elevated SAA is a causal factor in HDL dysfunction. HDL from AgNO3-injected mice lacking Saa1.1 and Saa2.1 exhibited a partial restoration of antiinflammatory and cholesterol efflux properties in adipocytes. Conversely, incorporation of SAA into HDL preparations reduced antiinflammatory properties but not to the same extent as HDL from AgNO3-injected mice. SAA-enriched HDL colocalized with cell surface-associated extracellular matrix (ECM) of adipocytes, suggesting impaired access to the plasma membrane. Enzymatic digestion of proteoglycans in the ECM restored the ability of SAA-containing HDL to inhibit palmitate-induced inflammation and cholesterol efflux. Collectively, these findings indicate that inflammation results in a loss of the antiinflammatory properties of HDL on adipocytes, which appears to partially result from the SAA component of HDL binding to cell-surface proteoglycans, thereby preventing access of HDL to the plasma membrane.
BACKGROUND: In the nonclassical form (NC), good correlation has been observed between genotypes and 17OH-progesterone (17-OHP) levels. However, this correlation was not identified with regard to the severity of hyperandrogenic manifestations, which could depend on interindividual variability in peri
pheral androgen sensitivity. Androgen action is modulated by the polymorphic CAG tract (nCAG) of the androgen receptor (AR) gene and by polymorphisms in 5alpha-reductase type 2 (SRD5A2) enzyme, both of which are involved in the severity of hyperandrogenic disorders. OBJECTIVES: To analyze whether nCAG-AR and SRD5A2 polymorphisms influence the severity of the nonclassical phenotype. PATIENTS: NC patients (n = 114) diagnosed by stimulated-17OHP >/=10 ng/mL were divided into groups according to the beginning of hyperandrogenic manifestations (pediatric and adolescent/adult) and CYP21A2 genotypes (C/C: homozygosis for mild mutations; A/C: compound heterozygosis for severe/mild mutations). METHODS: CYP21A2 mutations were screened by allelic-specific PCR, MLPA and/or sequencing. HpaII-digested and HpaII-undigested DNA samples underwent GeneScan analysis to study nCAG, and the SRD5A2 polymorphisms were screened by RLFP. RESULTS: Mean nCAG did not differ among pediatric, adolescent/adult and asymptomatic subjects. In the C/C genotype, we observed a significantly lower frequency of longer CAG alleles in pediatric patients than in adolescent/adults (p = 0.01). In patients carrying the A/C genotype, the frequencies of shorter and longer CAG alleles did not differ between pediatric patients and adolescent/adults (p>0.05). Patients with clitoromegaly had significantly lower weighted CAG biallelic mean than those without it: 19.1+/-2.7 and 21.6+/-2.5, respectively (p = 0.007), independent of the CYP21A2 genotype's severity. The SRD5A2 polymorphisms were not associated with the variability of hyperandrogenic NC phenotypes. CONCLUSIONS: In this series, we observed a modulatory effect of the CAG-AR tract on clinical manifestations of the NC form. Although the NC form is a monogenic disorder, our preliminary data suggested that the interindividual variability of the hyperandrogenic phenotype could arise from polygenic interactions.
We studied the genotype/phenotype correlation in a cohort of glycogen storage disease type (GSD) 1b patients. A total of 25 GSD1b patients, 13 females and 12 males, age range: 4.3-28.4 years, mean:14.6+/-6.8 years; median: 15 years, representing the entire case load of Italian GSD1b patients, were e
nrolled in the study. Molecular analysis of the glucose 6-phosphate translocase (G6PT1) gene was performed in all patients. We analysed the presence of a correlation among both the clinical features associated with GSD1b (neutropenia, frequency of admission to the hospital for severe infections) and the presence of systemic complications (liver adenomas, nephropathy, bone mineral density defect, polycystic ovaries, short stature, inflammatory bowel disease) and the mutations detected in each patient. Nine patients were homozygous or compound heterozygous for mutations causing stop codons. In particular, three patients were homozygous for the same mutation (400X); of these patients, one showed chronic neutropenia with severe and frequent infections and severe inflammatory bowel disease, another patient cyclic neutropenia associated with rare bacterial infections and mild bowel involvement and the last one normal neutrophil count. Two patients were homozygous for the mutation 128X; one of these patients did not show neutropenia, whereas the other one had severe neutropenia needing frequent hospital admission and was under granulocyte-colony stimulating factor treatment. In three patients no mutations were detected. CONCLUSION: No correlation was found between individual mutations and the presence of neutropenia, bacterial infections and systemic complications. These results suggest that different genes and proteins modulate neutrophil differentiation, maturation and apoptosis and thus the severity and frequency of infections. The absence of detectable mutations in three patients could suggest that a second protein plays a role in microsomal phosphate transport.
Benedetti A, etal., Biochem J 2002 Oct 15;367(Pt 2):505-10.
Histone 2A increases glucose-6-phosphatase activity in liver microsomes. The effect has been attributed either to the conformational change of the enzyme, or to the permeabilization of microsomal membrane that allows the free access of substrate to the intraluminal glucose-6-phosphatase catalytic si
te. The aim of the present study was the critical reinvestigation of the mechanism of action of histone 2A. It has been found that the dose-effect curve of histone 2A is different from that of detergents and resembles that of the pore-forming alamethicin. Inhibitory effects of EGTA on glucose-6-phosphatase activity previously reported in histone 2A-treated microsomes have been also found in alamethicin-permeabilized vesicles. The effect of EGTA cannot therefore simply be an antagonization of the effect of histone 2A. Histone 2A stimulates the activity of another latent microsomal enzyme, UDP-glucuronosyltransferase, which has an intraluminal catalytic site. Finally, histone 2A renders microsomal vesicles permeable to non-permeant compounds. Taken together, the results demonstrate that histone 2A stimulates glucose-6-phosphatase activity by permeabilizing the microsomal membrane.
Senesi S, etal., Biochem J. 2005 Jul 1;389(Pt 1):57-62.
Glucose 6-phosphate transport has been well characterized in liver microsomes. The transport is required for the functioning of the glucose-6-phosphatase enzyme that is situated in the lumen of the hepatic endoplasmic reticulum. The genetic deficiency of the glucose 6-phosphate transport activity ca
uses a severe metabolic disease termed type 1b glycogen storage disease. The cDNA encoding a liver transporter for glucose 6-phosphate was cloned and was found to be mutated in patients suffering from glycogen storage disease 1b. While related mRNAs have been described in liver and other tissues, the encoded protein(s) has not been immunologically characterized yet. In the present study, we report (using antibodies against three different peptides of the predicted amino acid sequence) that a major protein encoded by the glucose 6-phosphate transporter gene is expressed in the endoplasmic reticulum membranes of rat and human liver. The protein has an apparent molecular mass of approx. 33 kDa using SDS/PAGE, but several lines of evidence indicate that its real molecular mass is 46 kDa, as expected. The glucose 6-phosphate transporter protein was also immunodetected in kidney microsomes, but not in microsomes derived from human fibrocytes, rat spleen and lung, and a variety of cell lines. Moreover, little or no expression of the glucose 6-phosphate transporter protein was found in liver microsomes obtained from three glycogen storage disease 1b patients, even bearing mutations that do not directly interfere with protein translation, which can be explained by a (proteasome-mediated) degradation of the mutated transporter.
Mirandola S, etal., Gastroenterology. 2006 May;130(6):1661-9. Epub 2006 Mar 6.
BACKGROUND & AIMS: Hepatic steatosis is frequent in chronic hepatitis C. Several mechanisms might be implicated, including metabolic cofactors and direct viral effects on intracellular lipid pathways. In a transgenic mouse model, hepatitis C virus (HCV) was shown to inhibit microsomal triglyceride t
ransfer protein (MTP) activity, which is essential for hepatic lipoprotein assembly and secretion. No data are available on liver MTP activity in HCV-infected patients. We therefore investigated liver MTP gene expression and its lipid transfer activity in untreated cases infected with the major HCV genotypes showing variable degrees of hepatic steatosis. METHODS: MTP messenger RNA (mRNA) levels were measured by real-time polymerase chain reaction, and MTP activity was assessed by fluorescent assay in liver biopsy specimens of 58 HCV-positive patients. A set of metabolic and serum lipid markers was also measured at the time of liver biopsies. RESULTS: MTP mRNA levels showed a statistically significant (P = .001) inverse correlation with the degree of steatosis, independently of the HCV genotype. MTP mRNA levels also had an inverse correlation with serum insulin (P = .0002), homeostasis model assessment-insulin resistance (HOMA-IR) (P = .005), and body mass index (P = .02) in patients with HCV-1 and HCV-2 and with serum HCV-RNA (P = .02) in HCV-3 patients. Liver MTP-specific activity was significantly reduced in HCV-3 patients compared with those with other HCV genotypes (P = .004) and correlated with reduced serum cholesterol, apo B, and low-density lipoproteins. CONCLUSIONS: MTP may play a central role in HCV-related steatosis, being modulated by different genotype-specific mechanisms, mainly hyperinsulinemia in non-HCV-3 patients, and more profound and direct virus-related effects in HCV-3-infected individuals.
Galli L, etal., FEBS Lett. 1999 Oct 8;459(2):255-8.
Glycogen storage diseases type 1 (GSD 1) are a group of autosomal recessive disorders characterized by impairment of terminal steps of glycogenolysis and gluconeogenesis. Mutations of the glucose-6-phosphatase gene are responsible for the most frequent form of GSD 1, the subtype 1a, while mutations
of the glucose-6-phosphate transporter gene (G6PT) have recently been shown to cause the non 1a forms of GSD, namely the 1b and 1c subtypes. Here, we report on the analysis by single-stranded conformation polymorphism (SSCP) and/or DNA sequencing of the exons of the G6PT in 14 patients diagnosed either as affected by the GSD 1b or 1c subtypes. Mutations in the G6PT gene were found in all patients. Four of the detected mutations were novel mutations, while the others were previously described. Our results confirm that the GSD 1b and 1c forms are due to mutations in the same gene, i.e. the G6PT gene. We also show that the same kind of mutation can be associated or not with evident clinical complications such as neutrophil impairment. Since no correlation between the type and position of the mutation and the severity of the disease was found, other unknown factors may cause the expression of symptoms, such as neutropenia, which dramatically influence the severity of the disease.
Qu D, etal., J Biol Chem. 2015 Dec 18;290(51):30441-52. doi: 10.1074/jbc.M115.677815. Epub 2015 Nov 4.
Emerging evidence has demonstrated a growing genetic component in Parkinson disease (PD). For instance, loss-of-function mutations in PINK1 or PARKIN can cause autosomal recessive PD. Recently, PINK1 and PARKIN have been implicated in the same signaling pathway to regulate mitochondrial clearance t
hrough recruitment of PARKIN by stabilization of PINK1 on the outer membrane of depolarized mitochondria. The precise mechanisms that govern this process remain enigmatic. In this study, we identify Bcl2-associated athanogene 2 (BAG2) as a factor that promotes mitophagy. BAG2 inhibits PINK1 degradation by blocking the ubiquitination pathway. Stabilization of PINK1 by BAG2 triggers PARKIN-mediated mitophagy and protects neurons against 1-methyl-4-phenylpyridinium-induced oxidative stress in an in vitro cell model of PD. Collectively, our findings support the notion that BAG2 is an upstream regulator of the PINK1/PARKIN signaling pathway.
Ansar M, etal., Am J Hum Genet. 2019 Nov 7;105(5):907-920. doi: 10.1016/j.ajhg.2019.09.013. Epub 2019 Oct 10.
We report two consanguineous families with probands that exhibit intellectual disability, developmental delay, short stature, aphasia, and hypotonia in which homozygous non-synonymous variants were identified in IQSEC1 (GenBank: NM_001134382.3). In a Pakistani family, the IQSEC1 segregating variant
is c.1028C>T (p.Thr343Met), while in a Saudi Arabian family the variant is c.962G>A (p.Arg321Gln). IQSEC1-3 encode guanine nucleotide exchange factors for the small GTPase ARF6 and their loss affects a variety of actin-dependent cellular processes, including AMPA receptor trafficking at synapses. The ortholog of IQSECs in the fly is schizo and its loss affects growth cone guidance at the midline in the CNS, also an actin-dependent process. Overexpression of the reference IQSEC1 cDNA in wild-type flies is lethal, but overexpression of the two variant IQSEC1 cDNAs did not affect viability. Loss of schizo caused embryonic lethality that could be rescued to 2nd instar larvae by moderate expression of the human reference cDNA. However, the p.Arg321Gln and p.Thr343Met variants failed to rescue embryonic lethality. These data indicate that the variants behave as loss-of-function mutations. We also show that schizo in photoreceptors is required for phototransduction. Finally, mice with a conditional Iqsec1 deletion in cortical neurons exhibited an increased density of dendritic spines with an immature morphology. The phenotypic similarity of the affecteds and the functional experiments in flies and mice indicate that IQSEC1 variants are the cause of a recessive disease with intellectual disability, developmental delay, and short stature, and that axonal guidance and dendritic projection defects as well as dendritic spine dysgenesis may underlie disease pathogenesis.
Mitochondrial disorders are clinically and genetically heterogeneous, with variants in mitochondrial or nuclear genes leading to varied clinical phenotypes. TAMM41 encodes a mitochondrial protein with cytidine diphosphate-diacylglycerol synthase activity: an essential early step in the biosynthesis
of phosphatidylglycerol and cardiolipin. Cardiolipin is a mitochondria-specific phospholipid that is important for many mitochondrial processes. We report three unrelated individuals with mitochondrial disease that share clinical features, including lethargy at birth, hypotonia, developmental delay, myopathy, and ptosis. Whole exome and genome sequencing identified compound heterozygous variants in TAMM41 in each proband. Western blot analysis in fibroblasts showed a mild oxidative phosphorylation (OXPHOS) defect in only one of the three affected individuals. In skeletal muscle samples, however, there was severe loss of subunits of complexes I-IV and a decrease in fully assembled OXPHOS complexes I-V in two subjects as well as decreased TAMM41 protein levels. Similar to the tissue-specific observations on OXPHOS, cardiolipin levels were unchanged in subject fibroblasts but significantly decreased in the skeletal muscle of affected individuals. To assess the functional impact of the TAMM41 missense variants, the equivalent mutations were modeled in yeast. All three mutants failed to rescue the growth defect of the Δtam41 strains on non-fermentable (respiratory) medium compared with wild-type TAM41, confirming the pathogenicity of the variants. We establish that TAMM41 is an additional gene involved in mitochondrial phospholipid biosynthesis and modification and that its deficiency results in a mitochondrial disorder, though unlike families with pathogenic AGK (Sengers syndrome) and TAFAZZIN (Barth syndrome) variants, there was no evidence of cardiomyopathy.
OBJECTIVES: To determine whether B-cell markers (blood and minor salivary gland [SG] B-cell depletion [BCD], autoantibodies, B-cell-activating factor [BAFF]) are associated with clinical response to rituximab in patients with primary Sjogren's syndrome (pSS). METHODS: 45 patients with pSS were inclu
ded: in group I, 14 received low-dose rituximab (two 375-mg/m(2) infusions) in an open-labelled study; in group II, 17 received full-dose rituximab (two 1000-mg infusions) and 14 received a placebo in a randomized, controlled study. The proportion of SG B cells was assessed using pixel-based software analyses of digitized double-immunostained (CD3/CD20) whole SGs. Response was defined at week-24 according to the Sjogren's Syndrome Responder Index (SSRI)-30. RESULTS: Response rate was 50% in both groups of rituximab-treated patients. Duration of blood BCD was similar in both groups despite the difference in rituximab dosage, and was highly correlated with residual serum-rituximab levels at week-16. SG B-cell dynamics mirrored blood B-cell levels, with a drastic decrease in SG B-cells at week-12 (group I), but an increase in approximately 50% of patients in group II by week-24, in whom blood B cells had already returned. Duration of BCD was not associated with the clinical response, but responders had lower baseline proportions of SG B cells. Baseline serum BAFF level was correlated with the proportion of SG B-cells and other B-cell-activation markers, and was associated with the clinical response with higher levels in non-responders. CONCLUSIONS: In pSS, half of the patients display an intense BAFF-driven B-cell activation and do not respond to a single course of rituximab.
Cobblestone lissencephaly represents a peculiar brain malformation with characteristic radiological anomalies, defined as cortical dysplasia combined with dysmyelination, dysplastic cerebellum with cysts and brainstem hypoplasia. Cortical dysplasia results from neuroglial overmigration into the arac
hnoid space, forming an extracortical layer, responsible for agyria and/or 'cobblestone' brain surface and ventricular enlargement. The underlying mechanism is a disruption of the glia limitans, the outermost layer of the brain. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal recessive diseases with cerebral, ocular and muscular deficits, Walker-Warburg syndrome, muscle-eye-brain and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN and FKRP genes attributed these diseases to alpha-dystroglycanopathies. However, studies have not been able to identify causal mutations in the majority of patients and to establish a clear phenotype/genotype correlation. Therefore, we decided to perform a detailed neuropathological survey and molecular screenings in 65 foetal cases selected on the basis of histopathological criteria. After sequencing the six genes of alpha-dystroglycanopathies, a causal mutation was observed in 66% of cases. On the basis of a ratio of severity, three subtypes clearly emerged. The most severe, which we called cobblestone lissencephaly A, was linked to mutations in POMT1 (34%), POMT2 (8%) and FKRP (1.5%). The least severe, cobblestone lissencephaly C, was linked to POMGNT1 mutations (18%). An intermediary type, cobblestone lissencephaly B, was linked to LARGE mutations (4.5%) identified for the first time in foetuses. We conclude that cobblestone lissencephaly encompasses three distinct subtypes of cortical malformations with different degrees of neuroglial ectopia into the arachnoid space and cortical plate disorganization regardless of gestational age. In the cerebellum, histopathological changes support the novel hypothesis that abnormal lamination arises from a deficiency in granule cells. Our studies demonstrate the positive impact of histoneuropathology on the identification of alpha-dystroglycanopathies found in 66% of cases, while with neuroimaging criteria and biological values, mutations are found in 32-50% of patients. Interestingly, our morphological classification was central in the orientation of genetic screening of POMT1, POMT2, POMGNT1, LARGE and FKRP. Despite intensive research, one-third of our cases remained unexplained; suggesting that other genes and/or pathways may be involved. This material offers a rich resource for studies on the affected neurodevelopmental processes of cobblestone lissencephaly and on the identification of other responsible gene(s)/pathway(s).
Penisson-Besnier I, etal., Neuromuscul Disord. 2013 Aug;23(8):664-9. doi: 10.1016/j.nmd.2013.04.009. Epub 2013 Jun 12.
Complete deficiency of the extracellular matrix glycoprotein tenascin-X (TNX) leads to recessive forms of Ehlers-Danlos syndrome, clinically characterized by hyperextensible skin, easy bruising and joint hypermobility. Clinical and pathological studies, immunoassay, and molecular analyses were combi
ned to study a patient suffering from progressive muscle weakness. Clinical features included axial and proximal limb muscle weakness, subclinical heart involvement, minimal skin hyperextensibility, no joint abnormalities, and a history of easy bruising. Skeletal muscle biopsy disclosed striking muscle consistency and the abnormal presence of myotendinous junctions in the muscle belly. TNX immunostaining was markedly reduced in muscle and skin, and serum TNX levels were undetectable. Compound heterozygous mutations were identified: a previously reported 30kb deletion and a non-synonymous novel missense mutation in the TNXB gene. This study identifies a TNX-deficient patient presenting with a primary muscle disorder, thus expanding the phenotypic spectrum of TNX-related abnormalities. Biopsy findings provide evidence that TNX deficiency leads to muscle softness and to mislocalization of myotendinous junctions.
Chung HL, etal., Am J Hum Genet. 2020 May 7;106(5):717-725. doi: 10.1016/j.ajhg.2020.04.001. Epub 2020 Apr 23.
We identified three unrelated individuals with de novo missense variants in CDK19, encoding a cyclin-dependent kinase protein family member that predominantly regulates gene transcription. These individuals presented with hypotonia, global developmental delay, epileptic encephalopathy, and dysmorphi
c features. CDK19 is conserved between vertebrate and invertebrate model organisms, but currently abnormalities in CDK19 are not known to be associated with a human disorder. Loss of Cdk8, the fly homolog of CDK19, causes larval lethality, which is suppressed by expression of human CDK19 reference cDNA. In contrast, the CDK19 p.Tyr32His and p.Thr196Ala variants identified in the affected individuals fail to rescue the loss of Cdk8 and behave as null alleles. Additionally, neuronal RNAi-mediated knockdown of Cdk8 in flies results in semi-lethality. The few eclosing flies exhibit severe seizures and a reduced lifespan. Both phenotypes are fully suppressed by moderate expression of the CDK19 reference cDNA but not by expression of the two variants. Finally, loss of Cdk8 causes an obvious loss of boutons and synapses at larval neuromuscular junctions (NMJs). Together, our findings demonstrate that human CDK19 fully replaces the function of Cdk8 in the fly, the human disease-associated CDK19 variants behave as strong loss-of-function variants, and deleterious CDK19 variants underlie a syndromic neurodevelopmental disorder.
BACKGROUND: Idiopathic dilated cardiomyopathy (DCM) is the most frequent indication for orthotopic heart transplantation. It has been suggested that mutations in genes encoding desmosomal proteins, more typically associated with arrhythmogenic right ventricular cardiomyopathy, are a cause of DCM. OB
JECTIVES: To determine the frequency of desmosomal protein gene mutations in heart transplant recipients and their families and to examine histopathological characteristics of explanted organs from mutation carriers. METHODS: 89 unrelated patients aged 47.9+/-13.5 years (80% male) transplanted for end-stage DCM underwent genetic screening of five desmosomal genes (PKP2, DSP, DSC2, DSG2 and JUP). The findings were correlated with clinical features and histological characteristics in explanted hearts. RESULTS: Pathogenic mutations were identified in 12 patients (13%). Five additional patients (6%) had genetic variants of unknown significance. The clinical phenotype of patients with pathogenic mutations was indistinguishable from that observed in patients without mutations. Evaluation of 76 relatives from 14 families with sequence variants (11 with pathogenic mutations and three with variants of unknown effect) identified 38 mutation carriers, four of whom had an overt DCM phenotype. Evidence of co-segregation of mutations with DCM phenotype was found in five families. Histological evaluation of explanted hearts did not show any specific features in patients with pathogenic mutations. CONCLUSIONS: Mutations in desmosomal genes are frequent in patients with advanced DCM undergoing cardiac transplantation. These findings emphasise the importance of familial evaluation and genetic counselling in patients with end-stage DCM and pose important challenges for current histopathological criteria for arrhythmogenic right ventricular cardiomyopathy.
Guo H, etal., Nat Commun. 2019 Oct 15;10(1):4679. doi: 10.1038/s41467-019-12435-8.
Postsynaptic density (PSD) proteins have been implicated in the pathophysiology of neurodevelopmental and psychiatric disorders. Here, we present detailed clinical and genetic data for 20 patients with likely gene-disrupting mutations in TANC2-whose protein product interacts with multiple PSD protei
ns. Pediatric patients with disruptive mutations present with autism, intellectual disability, and delayed language and motor development. In addition to a variable degree of epilepsy and facial dysmorphism, we observe a pattern of more complex psychiatric dysfunction or behavioral problems in adult probands or carrier parents. Although this observation requires replication to establish statistical significance, it also suggests that mutations in this gene are associated with a variety of neuropsychiatric disorders consistent with its postsynaptic function. We find that TANC2 is expressed broadly in the human developing brain, especially in excitatory neurons and glial cells, but shows a more restricted pattern in Drosophila glial cells where its disruption affects behavioral outcomes.
NRAS and BRAF mutational status has become mandatory to treat patients with metastatic melanomas. Mutation-specific immunohistochemistry (IHC) can help analyze challenging tumor samples. We report our experience integrating NRASQ61R (SP174) and BRAFV600E (VE1) IHC in routine practice in a cancer mo
lecular genetic platform. All samples screened for BRAF and NRAS mutations during the year 2014 were analyzed by IHC and pyrosequencing, with an independent analysis of the 2 methods. Cases with first-line discordant results benefited from a complementary second-round IHC and next-generation sequencing (NGS) with a final interpretation taking into account the results of pyrosequencing, IHC, NGS, and quantification of the tumor cells. We analyzed 111 consecutive formalin-fixed and paraffin-embedded melanoma samples from 101 patients. Twenty-two and 11 samples were concordant for BRAFV600E and NRASQ61R mutations, respectively. Second-round analyses of 9 discordant and 1 molecularly inconclusive samples allowed conclusion in 4 further mutated samples (2 BRAFV600E and 2 NRASQ61R). A sample remained NRASQ61R IHC negative but NRASQ61R mutated with molecular methods. Overall, BRAFV600 and NRASQ61 mutation frequencies were 31.7% and 30.7%, respectively. When compared to molecular results, the sensitivity and specificity of IHC were 100% for BRAFV600E IHC and 92.3% and 98.9% for NRASQ61R IHC, respectively. IHC interpretation required a more stringent cutoff for BRAFV600E IHC than NRASQ61R to minimize false results. We conclude that NRASQ61R and BRAFV600E IHC coupled with NGS allow detection of mutations in melanoma challenging samples.
PURPOSE: Current evidence indicates that the common AMPD1 gene variant is associated with improved survival in patients with advanced heart failure. Whilst adenosine has been recognized to mediate the cardioprotective effect of C34T AMPD1, the precise pathophysiologic mechanism involved r
emains undefined to date. To address this issue, we used cardio-pulmonary exercise testing data (CPX) from subjects with myoadenylate deaminase (MAD) defects. METHODS: From 2009 to 2013, all the patients referred in our laboratory to perform a metabolic exercise testing, i.e. a CPX with measurements of muscle metabolites in plasma during and after exercise testing, were prospectively enrolled. Subjects that also underwent an open muscle biopsy for diagnosis purpose were finally included. The metabolic-chronotropic response was assessed by calculating the slope of the linear relationship between the percent heart rate reserve and the percent metabolic reserve throughout exercise. MAD activity was measured using the Fishbein's technique in muscle biopsy sample. The common AMPD1 mutation was genotyped and the AMPD1 gene was sequenced to screen rare variants from blood DNA. RESULTS: Sixty-seven patients were included in the study; 5 had complete MAD deficiency, 11 had partial MAD deficiency, and 51 had normal MAD activity. Compared with normal MAD activity subjects, MAD deficient subjects appeared to have a lower-than-expected metabolic-chronotopic response during exercise. The metabolic-chronotropic relationship is more closely correlated with MAD activity in skeletal muscle (Rs = 0.57, p = 5.93E-7, Spearman correlation) than the presence of the common AMPD1 gene variant (Rs = 0.34, p = 0.005). Age-predicted O2 pulse ratio is significantly increased in MAD deficient subjects, indicating a greater efficiency of the cardiovascular system to deliver O2 (p < 0.01, Scheffé's post hoc test). CONCLUSION: The metabolic-chronotropic response is decreased in skeletal muscle MAD deficiency, suggesting a biological mechanism by which AMPD1 gene exerts cardiac effect.
Triplett TA, etal., Proc Natl Acad Sci U S A. 2016 Feb 23;113(8):E1016-25. doi: 10.1073/pnas.1520245113. Epub 2016 Feb 9.
Primary T-cell acute lymphoblastic leukemia (T-ALL) cells require stromal-derived signals to survive. Although many studies have identified cell-intrinsic alterations in signaling pathways that promote T-ALL growth, the identity of endogenous stromal cells and their associated signals in the tumor m
icroenvironment that support T-ALL remains unknown. By examining the thymic tumor microenvironments in multiple murine T-ALL models and primary patient samples, we discovered the emergence of prominent epithelial-free regions, enriched for proliferating tumor cells and dendritic cells (DCs). Systematic evaluation of the functional capacity of tumor-associated stromal cells revealed that myeloid cells, primarily DCs, are necessary and sufficient to support T-ALL survival ex vivo. DCs support T-ALL growth both in primary thymic tumors and at secondary tumor sites. To identify a molecular mechanism by which DCs support T-ALL growth, we first performed gene expression profiling, which revealed up-regulation of platelet-derived growth factor receptor beta (Pdgfrb) and insulin-like growth factor I receptor (Igf1r) on T-ALL cells, with concomitant expression of their ligands by tumor-associated DCs. Both Pdgfrb and Igf1r were activated in ex vivo T-ALL cells, and coculture with tumor-associated, but not normal thymic DCs, sustained IGF1R activation. Furthermore, IGF1R signaling was necessary for DC-mediated T-ALL survival. Collectively, these studies provide the first evidence that endogenous tumor-associated DCs supply signals driving T-ALL growth, and implicate tumor-associated DCs and their mitogenic signals as auspicious therapeutic targets.
Adolescence has been linked to greater risk-taking and novelty-seeking behavior and a higher prevalence of drug abuse and risk of relapse. Decreases in cyclic adenosine monophosphate response element binding protein (CREB) and phosphorylated CREB (pCREB) have been reported after repeated cocaine adm
inistration in animal models. We compared the behavioral effects of cocaine and abstinence in adolescent and adult mice and investigated possible age-related differences in CREB and pCREB levels. Adolescent and adult male Swiss mice received one daily injection of saline or cocaine (10 mg/kg, i.p.) for 8 days. On day 9, the mice received a saline injection to evaluate possible environmental conditioning. After 9 days of withdrawal, the mice were tested in the elevated plus maze to evaluate anxiety-like behavior. Twelve days after the last saline/cocaine injection, the mice received a challenge injection of either cocaine or saline, and locomotor activity was assessed. One hour after the last injection, the brains were extracted, and CREB and pCREB levels were evaluated using Western blot in the prefrontal cortex (PFC) and hippocampus. The cocaine-pretreated mice during adolescence exhibited a greater magnitude of the expression of behavioral sensitization and greater cocaine withdrawal-induced anxiety-like behavior compared with the control group. Significant increases in CREB levels in the PFC and hippocampus and pCREB in the hippocampus were observed in cocaine-abstinent animals compared with the animals treated with cocaine in adulthood. Interestingly, significant negative correlations were observed between cocaine sensitization and CREB levels in both regions. These results suggest that the behavioral and neurochemical consequences of psychoactive substances in a still-developing nervous system can be more severe than in an already mature nervous system.
Lino-dos-Santos-Franco A, etal., Toxicol Lett. 2011 Dec 15;207(3):278-85. doi: 10.1016/j.toxlet.2011.09.026. Epub 2011 Oct 1.
Formaldehyde (FA) is an indoor and outdoor pollutant widely used by many industries, and its exposure is associated with inflammation and oxidative stress in the airways. Our previous studies have demonstrated the role of reactive oxygen species (ROS) in lung inflammation induced by FA inhalation bu
t did not identify source of the ROS. In the present study, we investigate the effects of FA on the activities and gene expression of glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), superoxide dismutase (SOD) 1 and 2, catalase (CAT), nitric oxide synthase (iNOS and cNOS) and cyclooxygenase (COX) 1 and 2. The hypothesized link between NADPH-oxidase, nitric oxide synthase and cyclooxygenase, the lung inflammation after FA inhalation was also investigated. For experiments, male Wistar rats were submitted to FA inhalation (1%, 90 min daily) for 3 consecutive days. The treatments with apocynin and indomethacin before the FA exposure reduced the number of neutrophils recruited into the lung. Moreover, the treatments with apocynin and indomethacin blunted the effect of FA on the generation of IL-1beta, while the treatments with L-NAME and apocynin reduced the generation of IL-6 by lung explants when compared to the untreated group. FA inhalation increased the levels of NO and hydrogen peroxide by BAL cells cultured and the treatments with apocynin and l-NAME reduced these generations. FA inhalation did not modify the activities of GPX, GR, GST and CAT but reduced the activity of SOD when compared to the naive group. Significant increases in SOD-1 and -2, CAT, iNOS, cNOS and COX-1 expression were observed in the FA group compared to the naive group. The treatments with apocynin, indomethacin and L-NAME reduced the gene expression of antioxidant and oxidant enzymes. In conclusion, our results indicate that FA causes a disruption of the physiological balance between oxidant and antioxidant enzymes in lung tissue, most likely favoring the oxidant pathways and thus positively modulating lung inflammation.
Fukuyama congenital muscular dystrophy (FCMD) is frequent in Japan, due to a founder mutation of the fukutin gene (FKTN). Outside Japan, FKTN mutations have only been reported in a few patients with a wide spectrum of phenotypes from Walker-Warburg syndrome to limb-girdle muscular dystrophy (LGMD2M)
. We studied four new Caucasian patients from three unrelated families. All showed raised serum CK initially isolated in one case and muscular dystrophy. Immunohistochemical studies and haplotype analysis led us to search for mutations in FKTN. Two patients (two sisters) presented with congenital muscular dystrophy, mental retardation, and posterior fossa malformation including cysts, and brain atrophy at Brain MRI. The other two patients had normal intelligence and brain MRI. Sequencing of the FKTN gene identified three previously described mutations and two novel missense mutations. Outside Japan, fukutinopathies are associated with a large spectrum of phenotypes from isolated hyperCKaemia to severe CMD, showing a clear overlap with that of FKRP.
The molecular basis underlying the clinical variability in symptomatic Duchenne muscular dystrophy (DMD) carriers are still to be precised. We report 26 cases of early symptomatic DMD carriers followed in the French neuromuscular network. Clinical presentation, muscular histological analysis and typ
e of gene mutation, as well as X-chromosome inactivation (XCI) patterns using DNA extracted from peripheral blood or muscle are detailed. The initial symptoms were significant weakness (88%) or exercise intolerance (27%). Clinical severity varied from a Duchenne-like progression to a very mild Becker-like phenotype. Cardiac dysfunction was present in 19% of the cases. Cognitive impairment was worthy of notice, as 27% of the carriers are concerned. The muscular analysis was always contributive, revealing muscular dystrophy (83%), mosaic in immunostaining (81%) and dystrophin abnormalities in western blot analysis (84%). In all, 73% had exonic deletions or duplications and 27% had point mutations. XCI pattern was biased in 62% of the cases. In conclusion, we report the largest series of manifesting DMD carriers at pediatric age and show that exercise intolerance and cognitive impairment may reveal symptomatic DMD carriers. The complete histological and immunohistological study of the muscle is the key of the diagnosis leading to the dystrophin gene analysis. Our study shows also that cognitive impairment in symptomatic DMD carriers is associated with mutations in the distal part of the DMD gene. XCI study does not fully explain the mechanisms as well as the wide spectrum of clinical phenotype, though a clear correlation between the severity of the phenotype and inactivation bias was observed.
Kim HJ, etal., Nat Commun. 2022 Apr 28;13(1):2306. doi: 10.1038/s41467-022-30015-1.
Missense variants in RNA-binding proteins (RBPs) underlie a spectrum of disease phenotypes, including amyotrophic lateral sclerosis, frontotemporal dementia, and inclusion body myopathy. Here, we present ten independent families with a severe, progressive muscular dystrophy, reminiscent of oculophar
yngeal muscular dystrophy (OPMD) but of much earlier onset, caused by heterozygous frameshift variants in the RBP hnRNPA2/B1. All disease-causing frameshift mutations abolish the native stop codon and extend the reading frame, creating novel transcripts that escape nonsense-mediated decay and are translated to produce hnRNPA2/B1 protein with the same neomorphic C-terminal sequence. In contrast to previously reported disease-causing missense variants in HNRNPA2B1, these frameshift variants do not increase the propensity of hnRNPA2 protein to fibrillize. Rather, the frameshift variants have reduced affinity for the nuclear import receptor karyopherin β2, resulting in cytoplasmic accumulation of hnRNPA2 protein in cells and in animal models that recapitulate the human pathology. Thus, we expand the phenotypes associated with HNRNPA2B1 to include an early-onset form of OPMD caused by frameshift variants that alter its nucleocytoplasmic transport dynamics.
El Khoury NB, etal., Neurobiol Dis. 2016 Apr;88:55-65. doi: 10.1016/j.nbd.2016.01.005. Epub 2016 Jan 9.
Accumulating evidence from epidemiological studies suggest that type 2 diabetes is linked to an increased risk of Alzheimer's disease (AD). However, the consequences of type 2 diabetes on AD pathologies, such as tau hyperphosphorylation, are not well understood. Here, we evaluated the impact of type
2 diabetes on tau phosphorylation in db/db diabetic mice aged 4 and 26weeks. We found increased tau phosphorylation at the CP13 epitope correlating with a deregulation of c-Jun. N-terminal kinase (JNK) and Protein Phosphatase 2A (PP2A) in 4-week-old db/db mice. 26-week-old db/db mice displayed tau hyperphosphorylation at multiple epitopes (CP13, AT8, PHF-1), but no obvious change in kinases or phosphatases, no cleavage of tau, and no deregulation of central insulin signaling pathways. In contrast to younger animals, 26-week-old db/db mice were hypothermic and restoration of normothermia rescued phosphorylation at most epitopes. Our results suggest that, at early stages of type 2 diabetes, changes in tau phosphorylation may be due to deregulation of JNK and PP2A, while at later stages hyperphosphorylation is mostly a consequence of hypothermia. These results provide a novel link between diabetes and tau pathology, and underlie the importance of recording body temperature to better understand the relationship between diabetes and AD.
Mokbel N, etal., Brain. 2013 Feb;136(Pt 2):494-507. doi: 10.1093/brain/aws348. Epub 2013 Jan 31.
Mutations in the TPM2 gene, which encodes beta-tropomyosin, are an established cause of several congenital skeletal myopathies and distal arthrogryposis. We have identified a TPM2 mutation, p.K7del, in five unrelated families with nemaline myopathy and a consistent distinctive clinical phenotype. Pa
tients develop large joint contractures during childhood, followed by slowly progressive skeletal muscle weakness during adulthood. The TPM2 p.K7del mutation results in the loss of a highly conserved lysine residue near the N-terminus of beta-tropomyosin, which is predicted to disrupt head-to-tail polymerization of tropomyosin. Recombinant K7del-beta-tropomyosin incorporates poorly into sarcomeres in C2C12 myotubes and has a reduced affinity for actin. Two-dimensional gel electrophoresis of patient muscle and primary patient cultured myotubes showed that mutant protein is expressed but incorporates poorly into sarcomeres and likely accumulates in nemaline rods. In vitro studies using recombinant K7del-beta-tropomyosin and force measurements from single dissected patient myofibres showed increased myofilament calcium sensitivity. Together these data indicate that p.K7del is a common recurrent TPM2 mutation associated with mild nemaline myopathy. The p.K7del mutation likely disrupts head-to-tail polymerization of tropomyosin, which impairs incorporation into sarcomeres and also affects the equilibrium of the troponin/tropomyosin-dependent calcium switch of muscle. Joint contractures may stem from chronic muscle hypercontraction due to increased myofibrillar calcium sensitivity while declining strength in adulthood likely arises from other mechanisms, such as myofibre decompensation and fatty infiltration. These results suggest that patients may benefit from therapies that reduce skeletal muscle calcium sensitivity, and we highlight late muscle decompensation as an important cause of morbidity.
Chung HL, etal., Neuron. 2020 May 20;106(4):589-606.e6. doi: 10.1016/j.neuron.2020.02.021. Epub 2020 Mar 12.
ACOX1 (acyl-CoA oxidase 1) encodes the first and rate-limiting enzyme of the very-long-chain fatty acid (VLCFA) β-oxidation pathway in peroxisomes and leads to H2O2 production. Unexpectedly, Drosophila (d) ACOX1 is mostly expressed and required in glia, and loss of ACOX1 leads to developmental delay
, pupal death, reduced lifespan, impaired synaptic transmission, and glial and axonal loss. Patients who carry a previously unidentified, de novo, dominant variant in ACOX1 (p.N237S) also exhibit glial loss. However, this mutation causes increased levels of ACOX1 protein and function resulting in elevated levels of reactive oxygen species in glia in flies and murine Schwann cells. ACOX1 (p.N237S) patients exhibit a severe loss of Schwann cells and neurons. However, treatment of flies and primary Schwann cells with an antioxidant suppressed the p.N237S-induced neurodegeneration. In summary, both loss and gain of ACOX1 lead to glial and neuronal loss, but different mechanisms are at play and require different treatments.
Lu S, etal., Am J Hum Genet. 2022 Apr 7;109(4):571-586. doi: 10.1016/j.ajhg.2022.01.020. Epub 2022 Mar 2.
TIAM Rac1-associated GEF 1 (TIAM1) regulates RAC1 signaling pathways that affect the control of neuronal morphogenesis and neurite outgrowth by modulating the actin cytoskeletal network. To date, TIAM1 has not been associated with a Mendelian disorder. Here, we describe five individuals with bi-alle
lic TIAM1 missense variants who have developmental delay, intellectual disability, speech delay, and seizures. Bioinformatic analyses demonstrate that these variants are rare and likely pathogenic. We found that the Drosophila ortholog of TIAM1, still life (sif), is expressed in larval and adult central nervous system (CNS) and is mainly expressed in a subset of neurons, but not in glia. Loss of sif reduces the survival rate, and the surviving adults exhibit climbing defects, are prone to severe seizures, and have a short lifespan. The TIAM1 reference (Ref) cDNA partially rescues the sif loss-of-function (LoF) phenotypes. We also assessed the function associated with three TIAM1 variants carried by two of the probands and compared them to the TIAM1 Ref cDNA function in vivo. TIAM1 p.Arg23Cys has reduced rescue ability when compared to TIAM1 Ref, suggesting that it is a partial LoF variant. In ectopic expression studies, both wild-type sif and TIAM1 Ref are toxic, whereas the three variants (p.Leu862Phe, p.Arg23Cys, and p.Gly328Val) show reduced toxicity, suggesting that they are partial LoF variants. In summary, we provide evidence that sif is important for appropriate neural function and that TIAM1 variants observed in the probands are disruptive, thus implicating loss of TIAM1 in neurological phenotypes in humans.
Garcia RC, etal., Sci Rep. 2015 Dec 2;5:17555. doi: 10.1038/srep17555.
The smoke of crack cocaine contains cocaine and its pyrolysis product, anhydroecgonine methyl ester (AEME). AEME possesses greater neurotoxic potential than cocaine and an additive effect when they are combined. Since atropine prevented AEME-induced neurotoxicity, it has been suggested that its tox
ic effects may involve the muscarinic cholinergic receptors (mAChRs). Our aim is to understand the interaction between AEME and mAChRs and how it can lead to neuronal death. Using a rat primary hippocampal cell culture, AEME was shown to cause a concentration-dependent increase on both total [(3)H]inositol phosphate and intracellular calcium, and to induce DNA fragmentation after 24 hours of exposure, in line with the activation of caspase-3 previously shown. Additionally, we assessed AEME activity at rat mAChR subtypes 1-5 heterologously expressed in Chinese Hamster Ovary cells. l-[N-methyl-(3)H]scopolamine competition binding showed a preference of AEME for the M2 subtype; calcium mobilization tests revealed partial agonist effects at M1 and M3 and antagonist activity at the remaining subtypes. The selective M1 and M3 antagonists and the phospholipase C inhibitor, were able to prevent AEME-induced neurotoxicity, suggesting that the toxicity is due to the partial agonist effect at M1 and M3 mAChRs, leading to DNA fragmentation and neuronal death by apoptosis.
Type II lissencephaly (type II LIS) is a group of autosomal recessive congenital muscular dystrophies (CMD) associated with defects in alpha-DG O-glycosylation, which comprises Walker-Warburg syndrome, Fukuyama cerebral and muscular dystrophy, or muscle-eye-brain disease. The most severe forms of t
hese diseases often have a fetal presentation and lead to a pregnancy termination. We report here the first molecular study on fetal type II LIS in a series of 47 fetuses from 41 unrelated families. Sequencing of the different genes known to be involved in alpha-DG O-glycosylation allowed the molecular diagnosis in 22 families: involvement of POMT1 was demonstrated in 32% of cases, whereas POMGNT1 and POMT2 were incriminated in 15% and in 7% of cases, respectively. We found 30 different mutations in these three genes, 25 were described herein for the first time, 15 in POMT1, and five in POMT2 and POMGNT1. Despite sequencing of FKRP, FCMD, and LARGE, no definitive molecular diagnosis could be made for the other half of our cases. Preliminary results concerning genotype-phenotype correlations show that the choice of the first gene sequenced should depend on the clinical severity of the type II LIS; POMT1 and POMT2 for severest clinical picture and POMGNT1 for milder disease. The other genes, FKRP, FCMD, and LARGE, seem not to be implicated in the fetal form of CMD.
Complex cortical malformations associated with mutations in tubulin genes are commonly referred to as "Tubulinopathies". To further characterize the mutation frequency and phenotypes associated with tubulin mutations, we studied a cohort of 60 foetal cases. Twenty-six tubulin mutations were identifi
ed, of which TUBA1A mutations were the most prevalent (19 cases), followed by TUBB2B (6 cases) and TUBB3 (one case). Three subtypes clearly emerged. The most frequent (n = 13) was microlissencephaly with corpus callosum agenesis, severely hypoplastic brainstem and cerebellum. The cortical plate was either absent (6/13), with a 2-3 layered pattern (5/13) or less frequently thickened (2/13), often associated with neuroglial overmigration (4/13). All cases had voluminous germinal zones and ganglionic eminences. The second subtype was lissencephaly (n = 7), either classical (4/7) or associated with cerebellar hypoplasia (3/7) with corpus callosum agenesis (6/7). All foetuses with lissencephaly and cerebellar hypoplasia carried distinct TUBA1A mutations, while those with classical lissencephaly harbored recurrent mutations in TUBA1A (3 cases) or TUBB2B (1 case). The third group was polymicrogyria-like cortical dysplasia (n = 6), consisting of asymmetric multifocal or generalized polymicrogyria with inconstant corpus callosum agenesis (4/6) and hypoplastic brainstem and cerebellum (3/6). Polymicrogyria was either unlayered or 4-layered with neuronal heterotopias (5/6) and occasional focal neuroglial overmigration (2/6). Three had TUBA1A mutations and 3 TUBB2B mutations. Foetal TUBA1A tubulinopathies most often consist in microlissencephaly or classical lissencephaly with corpus callosum agenesis, but polymicrogyria may also occur. Conversely, TUBB2B mutations are responsible for either polymicrogyria (4/6) or microlissencephaly (2/6).
Baala L, etal., Am J Hum Genet. 2007 Jul;81(1):170-9. Epub 2007 Jun 4.
Meckel syndrome (MKS) is a rare autosomal recessive lethal condition characterized by central nervous system malformations, polydactyly, multicystic kidney dysplasia, and ductal changes of the liver. Three loci have been mapped (MKS1-MKS3), and two genes have been identified (MKS1/FLJ20345 and MKS3/
TMEM67), whereas the gene at the MKS2 locus remains unknown. To identify new MKS loci, a genomewide linkage scan was performed using 10-cM-resolution microsatellite markers in eight families. The highest heterogeneity LOD score was obtained for chromosome 12, in an interval containing CEP290, a gene recently identified as causative of Joubert syndrome (JS) and isolated Leber congenital amaurosis. In view of our recent findings of allelism, at the MKS3 locus, between these two disorders, CEP290 was considered a candidate, and homozygous or compound heterozygous truncating mutations were identified in four families. Sequencing of additional cases identified CEP290 mutations in two fetuses with MKS and in four families presenting a cerebro-reno-digital syndrome, with a phenotype overlapping MKS and JS, further demonstrating that MKS and JS can be variable expressions of the same ciliopathy. These data identify a fourth locus for MKS (MKS4) and the CEP290 gene as responsible for MKS.
Distal arthrogryposis (DA) is a heterogeneous subgroup of arthrogryposis multiplex congenita (AMC), a large family of disorders characterized by multiple congenital joint limitations due to reduced fetal movements. DA is mainly characterized by contractures afflicting especially the distal extremiti
es without overt muscular or neurological signs. Although a limited number of genes mostly implicated in the contractile apparatus have been identified in DA, most patients failed to show mutations in currently known genes. Using a pangenomic approach, we demonstrated linkage of DA to chromosome 2q37 in two consanguineous families and the endothelin-converting enzyme like 1 (ECEL1) gene present in this region was associated with DA. Screening of a panel of 20 families with non-specific DA identified seven homozygous or compound heterozygous mutations of ECEL1 in a total of six families. Mutations resulted mostly in the absence of protein. ECEL1 is a neuronal endopeptidase predominantly expressed in the central nervous system and brain structures during fetal life in mice and human. ECEL1 plays a major role in intramuscular axonal branching of motor neurons in skeletal muscle during embryogenesis. A detailed review of clinical findings of DA patients with ECEL1 mutations revealed a homogeneous and recognizable phenotype characterized by limited knee flexion, flexed third to fifth fingers and severe muscle atrophy predominant on lower limbs and tongue that suggested a common pathogenic mechanism. We described a new and homogenous phenotype of DA associated with ECEL1 that resulted in symptoms involving rather the peripheral than the central nervous system and suggesting a developmental dysfunction.
Despite recent progress in the genetic characterization of congenital muscle diseases, the genes responsible for a significant proportion of cases remain unknown. We analysed two branches of a large consanguineous family in which four patients presented with a severe new phenotype, clinically marke
d by neonatal-onset muscle weakness predominantly involving axial muscles, life-threatening respiratory failure, skin abnormalities and joint hyperlaxity without contractures. Muscle biopsies showed the unreported association of multi-minicores, caps and dystrophic lesions. Genome-wide linkage analysis followed by gene and exome sequencing in patients identified a homozygous nonsense mutation in TRIP4 encoding Activating Signal Cointegrator-1 (ASC-1), a poorly characterized transcription coactivator never associated with muscle or with human inherited disease. This mutation resulted in TRIP4 mRNA decay to around 10% of control levels and absence of detectable protein in patient cells. ASC-1 levels were higher in axial than in limb muscles in mouse, and increased during differentiation in C2C12 myogenic cells. Depletion of ASC-1 in cultured muscle cells from a patient and in Trip4 knocked-down C2C12 led to a significant reduction in myotube diameter ex vivo and in vitro, without changes in fusion index or markers of initial myogenic differentiation. This work reports the first TRIP4 mutation and defines a novel form of congenital muscle disease, expanding their histological, clinical and molecular spectrum. We establish the importance of ASC-1 in human skeletal muscle, identify transcriptional co-regulation as novel pathophysiological pathway, define ASC-1 as a regulator of late myogenic differentiation and suggest defects in myotube growth as a novel myopathic mechanism.
Amigo-Jimenez I, etal., Oncotarget. 2015 Dec 29;6(42):44832-48. doi: 10.18632/oncotarget.6265.
CLL remains an incurable disease in spite of the many new compounds being studied. Arsenic trioxide (ATO) induces apoptosis in all CLL cell types and could constitute an efficient therapy. To further explore this, we have studied the influence of stromal cells, key components of the CLL microenviron
ment, on the response of CLL cells to ATO. Bone marrow stromal cells induced CLL cell resistance to 2 muM ATO and led to activation of Lyn, ERK, PI3K and PKC, as well as NF-kappaB and STAT3. Mcl-1, Bcl-xL, and Bfl-1 were also upregulated after the co-culture. Inhibition experiments indicated that PI3K and PKC were involved in the resistance to ATO induced by stroma. Moreover, idelalisib and sotrastaurin, specific inhibitors for PI3Kdelta and PKCbeta, respectively, inhibited Akt phosphorylation, NF-kappaB/STAT3 activation and Mcl-1 upregulation, and rendered cells sensitive to ATO. Mcl-1 was central to the mechanism of resistance to ATO, since: 1) Mcl-1 levels correlated with the CLL cell response to ATO, and 2) blocking Mcl-1 expression or function with specific siRNAs or inhibitors overcame the protecting effect of stroma. We have therefore identified the mechanism involved in the CLL cell resistance to ATO induced by bone marrow stroma and show that idelalisib or sotrastaurin block this mechanism and restore sensibility to ATO. Combination of ATO with these inhibitors may thus constitute an efficient treatment for CLL.
Volpi S, etal., J Exp Med. 2017 Mar 6;214(3):623-637. doi: 10.1084/jem.20161525. Epub 2017 Feb 1.
We studied three patients with severe skeletal dysplasia, T cell immunodeficiency, and developmental delay. Whole-exome sequencing revealed homozygous missense mutations affecting exostosin-like 3 (EXTL3), a glycosyltransferase involved in heparan sulfate (HS) biosynthesis. Patient-derived fibroblas
ts showed abnormal HS composition and altered fibroblast growth factor 2 signaling, which was rescued by overexpression of wild-type EXTL3 cDNA. Interleukin-2-mediated STAT5 phosphorylation in patients' lymphocytes was markedly reduced. Interbreeding of the extl3-mutant zebrafish (box) with Tg(rag2:green fluorescent protein) transgenic zebrafish revealed defective thymopoiesis, which was rescued by injection of wild-type human EXTL3 RNA. Targeted differentiation of patient-derived induced pluripotent stem cells showed a reduced expansion of lymphohematopoietic progenitor cells and defects of thymic epithelial progenitor cell differentiation. These data identify EXTL3 mutations as a novel cause of severe immune deficiency with skeletal dysplasia and developmental delay and underline a crucial role of HS in thymopoiesis and skeletal and brain development.
Lamiquiz-Moneo I, etal., Sci Rep. 2019 Jul 24;9(1):10770. doi: 10.1038/s41598-019-47283-5.
The aim of our study was to investigate a large cohort of overweight subjects consuming a homogeneous diet to identify the genetic factors associated with weight loss that could be used as predictive markers in weight loss interventions. We retrospectively recruited subjects (N = 788) aged over 18 y
ears with a Body Mass Index (BMI) between 25 and 40 kg/m2 who were treated at our lipid unit for at least one year from 2008 to 2016, and we also recruited a control group (168 patients) with normal BMIs. All participants received counselling from a nutritionist that included healthy diet and physical activity recommendations. We genotyped 25 single nucleotide variants (SNVs) in 25 genes that were previously associated with obesity and calculated genetic scores that were derived from 25 SNVs. The risk allele in CADM2 showed a higher frequency in overweight and obese subjects than in controls (p = 0.007). The mean follow-up duration was 5.58 ± 2.68 years. Subjects with lower genetic scores showed greater weight loss during the follow-up period. The genetic score was the variable that best explained the variations in weight from the baseline. The genetic score explained 2.4% of weight change variance at one year and 1.6% of weight change variance at the end of the follow-up period after adjusting for baseline weight, sex, age and years of follow-up.
BACKGROUND: Several studies have investigated single nucleotide polymorphisms (SNP) in candidate genes associated with susceptibility, severity or outcome in patients with community-acquired pneumonia (CAP) with conflicting results. METHODS: Multi-centre, prospective observational study. We studied
1162 white Spanish patients with CAP and 1413 controls. Severe forms of sepsis were recorded in 325 patients. Subjects were genotyped for the following polymorphisms: TNF -238 and -308, LTA +252, IL6 -174, IL1RN 86bp variable number of tandem repeats and TNFRSF1B+676 (TNFR2 M196R). RESULTS: No significant differences in genotype or allele frequencies were seen among patients and controls. We did not find any association between TNF, LTA, IL6 and IL1RN polymorphisms with disease severity or outcome. Analysis of 28-day mortality showed a significant difference in the distribution of TNFRSF1B+676 G/T genotypes (p=0.0129). Sequential Kaplan-Meier survival analysis of TNFRSF1B+676 G/T polymorphism showed a protective role of the GT genotype. Cox regression analysis adjusted for age, gender, hospital of origin and comorbidities showed that patients with GT genotypes had lower mortality rates compared to patients with GG or TT genotypes (p=0.02; HR 0.53; 95% CI 0.31-0.90 for 90-day survival; p=0.01; HR 0.41; 95% CI 0.21-0.81 for 28-day survival and p=0.049; HR 0.48; 95% CI 0.23-0.997 for 15-day survival). CONCLUSIONS: Our study does not support a role for the controversial studied polymorphisms of the TNF, LTA, IL6 and IL1RN genes in the susceptibility or outcome of CAP. A protective role of heterozygosity for the functionally relevant TNFRSF1B+676 polymorphism in the outcome of CAP was observed.
BACKGROUND: Community-acquired pneumonia (CAP) is the leading cause of death from infection in developed countries. Mannose-binding lectin (MBL) and MBL-associated serine protease 2 (MASP-2) deficiencies are common primary immunodeficiencies the clinical penetrance of which remains controversial. MB
L is a serum lectin that mediates phagocytosis and activates the lectin pathway of complement involving MASP-2. OBJECTIVE: We sought to evaluate the significance of MBL deficiency (O/O genotypes) and insufficiency (O/O plus XA/O genotypes), as well as MASP-2 deficiency (D105G mutation), in the susceptibility to and severity and outcome of CAP in adults. METHODS: MBL and MASP-2 serum levels, as well as lectin pathway activity with regard to MBL2 and MASP2 genotypes, were measured in healthy control subjects. For susceptibility, 848 patients with CAP, 1447 healthy control subjects, and a control group of 519 patients without relevant infectious diseases were studied in a case-control study. Severity and outcome were evaluated in a prospective study of the 848 patients. RESULTS: We found similar frequencies of MBL2 and MASP2 alleles and genotypes among patients and control subjects. However, in a multivariate analysis MBL insufficiency was associated with the development of the most severe forms of sepsis (P = .007), acute respiratory failure (P = .009), multiorgan dysfunction syndrome (P = .036), intensive care unit admission (P = .020), and death (P = .003). CONCLUSION: Our large study suggests that MBL plays a redundant role in human defenses against primary infection, at least in adults with CAP, and provides, for the first time, evidence that MBL insufficiency predisposes to higher severity and fatal outcome in patients with CAP, irrespective of the causal microorganisms.
BACKGROUND: Osteoprotegerin (OPG), a secreted member of the tumour necrosis factor receptor superfamily of cytokines, has been associated with endothelial dysfunction. We studied in type 2 diabetic and/or hypertensive patients the relationship between serum OPG and vascular alterations associated wi
th these pathologies. MATERIALS AND METHODS: We analysed 191 consecutive patients (52 with type 2 diabetes and 139 hypertensive nondiabetic patients) and 54 healthy controls. We assessed the relationship of OPG serum levels measured by ELISA with basal glycaemia, glycosylated haemoglobin, blood pressure, endothelial dysfunction (assessed by pulse wave velocity), retinopathy (by Keith-Wagener classification), left ventricular hypertrophy (by Cornell index), cardiovascular risk and target organs (heart, vascular, kidney) damage. RESULTS: Serum OPG levels were higher in either hypertensive or diabetic patients and in patients with non-dipper and riser circadian blood pressure patterns. We found significant correlations between OPG levels and age, height, glycaemia, systolic, diastolic and pulse blood pressure, pulse wave velocity and left ventricular hypertrophy in both hypertensive and diabetic patients. OPG levels were also higher in hypertensive patients with retinopathy, patients with high probability of 10-year cardiovascular risk, patients with three or more damaged target organs (heart, vessels, kidneys) and patients with previous episodes of ischaemic cardiopathy or hypercholesterolaemia. CONCLUSIONS: Osteoprotegerin is an indicator of diabetes- and hypertension-associated vascular pathologies as endothelial dysfunction and cardiovascular risk.
Garcia-Criado FJ, etal., J Interferon Cytokine Res. 2009 Jun 10.
Renal ischemia/reperfusion (I/R) is characterized by severe inflammatory damage. We assessed the effect of administrating recently developed nitrosothiol compounds acting as nitric oxide (NO) donors on the production of cytokines and other markers of acute inflammatory reaction in an experimental mo
del of warm (I/R), and in a model of cold ischemia and transplant in rats. Warm ischemia was achieved by ligation of left renal pedicle for 60 min, followed by contralateral nephrectomy. NO-donors LA-803, LA-807, LA-810 were administered i.v. (1.8 mumol/kg) during 30 min before reperfusion. Cold ischemia was achieved by preservating the kidney for 24 h in Euro Collins and grafting it in consanguineous Fisher 344/Ico rats. LA-803 was administered in the preservation fluid and in the recipient rat. Reperfusion time was 4 h in warm ischemia and 3 h in cold ischemia + transplantation. Administration of LA-803, LA-807 and, in a lower proportion, LA-810 prevented from the enhanced production of tumor necrosis factor (TNF), interferon-gamma (IFN-gamma), and interleukin-1beta (IL-1beta), the decrease in interleukin-6 (IL-6) and interleukin-10 (IL-10), the increase in tissue level of superoxide anion (SOA) and superoxide dismutase (SOD), and the increase in neutrophil infiltration induced by warm I/R. Treatment with LA-803 in animals with renal transplantation after cold ischemia was also associated with reduced plasma levels of TNF, IFN-gamma, and IL-1beta, increased plasma levels of IL-6 and IL-10, reduced renal levels of SOA and SOD, and reduced neutrophil infiltration. These data demonstrate that systemic administration of new NO-donors with nitrosothiol structure diminished inflammatory responses in a kidney subjected to warm I/R or cold ischemia and transplantation.
Kasher PR, etal., Am J Hum Genet. 2016 Feb 4;98(2):363-72. doi: 10.1016/j.ajhg.2015.12.014. Epub 2016 Jan 28.
Genetic studies of intellectual disability and identification of monogenic causes of obesity in humans have made immense contribution toward the understanding of the brain and control of body mass. The leptin > melanocortin > SIM1 pathway is dysregulated in multiple monogenic human obesity syndromes
but its downstream targets are still unknown. In ten individuals from six families, with overlapping 6q16.1 deletions, we describe a disorder of variable developmental delay, intellectual disability, and susceptibility to obesity and hyperphagia. The 6q16.1 deletions segregated with the phenotype in multiplex families and were shown to be de novo in four families, and there was dramatic phenotypic overlap among affected individuals who were independently ascertained without bias from clinical features. Analysis of the deletions revealed a approximately 350 kb critical region on chromosome 6q16.1 that encompasses a gene for proneuronal transcription factor POU3F2, which is important for hypothalamic development and function. Using morpholino and mutant zebrafish models, we show that POU3F2 lies downstream of SIM1 and controls oxytocin expression in the hypothalamic neuroendocrine preoptic area. We show that this finding is consistent with the expression patterns of POU3F2 and related genes in the human brain. Our work helps to further delineate the neuro-endocrine control of energy balance/body mass and demonstrates that this molecular pathway is conserved across multiple species.
Sole-Violan J, etal., Crit Care Med. 2011 Jun;39(6):1388-93.
OBJECTIVE: To assess the potential association of the functional polymorphism rs1801274 in the receptor IIa for the Fc portion of immunoglobin G (FcgammaRIIa) gene (FCGR2A-H131R) with the susceptibility to and the severity of community-acquired pneumonia (CAP). DESIGN: Multicenter prospective and ob
servational study. SETTING: Four university hospitals in Spain. PATIENTS: FCGR2A-H131R polymorphism was determined in 1,262 patients with CAP and in 1,224 in the subject control group. MEASUREMENTS AND MAIN RESULTS: Severe sepsis was recorded in 366 patients. No significant differences in genotype or allele frequencies were seen among patients with CAP or pneumococcal CAP (PCAP) and controls. Patients with bacteremic PCAP (B-PCAP) had significantly higher frequencies of FCGR2A-H/H131 genotypes than those with nonbacteremic PCAP (p = .00016, odds ratio = 2.9, 95% confidence interval 1.58-5.3). The differences remained significant when adjusting for pneumonia severity index, hospital of origin, and intensive care unit admission (p = .0012, odds ratio = 2.83, 95% confidence interval 1.51-5.32). B-PCAP was associated with a significantly higher severity of the disease, evaluated as sepsis severity (p = .000007, odds ratio = 4.40, 95% confidence interval 2.31-8.39), multiorgan dysfunction syndrome (0.00048, odds ratio = 3.29, 95% confidence interval 1.69-6.41), intensive care unit admission, acute renal failure, and acute respiratory distress syndrome. CONCLUSIONS: Our results do not support a role of FCGR2A-H131R polymorphism in susceptibility to CAP or PCAP. However, we provide the insight that homozygosity for FCGR2A-H131 predisposes B-PCAP, which was associated with higher severity in our study.
BACKGROUND: Common polymorphisms have been identified in genes suspected to play a role in asthma. We investigated their associations with wheeze and allergy in a case-control sample from Phase 2 of the International Study of Asthma and Allergies in Childhood. METHODS: We compared 1105 wheezing and
3137 non-wheezing children aged 8-12 years from 17 study centres in 13 countries. Genotyping of 55 candidate single nucleotide polymorphisms (SNPs) in 14 genes was performed using the Sequenom System. Logistic regression models were fitted separately for each centre and each SNP. A combined per allele odds ratio and measures of heterogeneity between centres were derived by random effects meta-analysis. RESULTS: Significant associations with wheeze in the past year were detected in only four genes (IL4R, TLR4, MS4A2, TLR9, P<0.05), with per allele odds ratios generally <1.3. Variants in IL4R and TLR4 were also related to allergen-specific IgE, while polymorphisms in FCER1B (MS4A2) and TLR9 were not. There were also highly significant associations (P<0.001) between SPINK5 variants and visible eczema (but not IgE levels) and between IL13 variants and total IgE. Heterogeneity of effects across centres was rare, despite differences in allele frequencies. CONCLUSIONS: Despite the biological plausibility of IgE-related mechanisms in asthma, very few of the tested candidates showed evidence of association with both wheeze and increased IgE levels. We were unable to confirm associations of the positional candidates DPP10 and PHF11 with wheeze, although our study had ample power to detect the expected associations of IL13 variants with IgE and SPINK5 variants with eczema.
Santos MC, etal., Stem Cells Dev. 2015 Nov 15;24(22):2700-8. doi: 10.1089/scd.2015.0052. Epub 2015 Aug 10.
Misexpression of stem cell-related genes may occur in some cancer cells, influencing patient's prognosis. This is the case of medulloblastoma, a common and clinically challenging malignant tumor of the central nervous system, where expression of the pluripotency factor, OCT4, is correlated with poor
survival. A downstream target of OCT4, L1TD1 (LINE-1 type transposase domain-containing protein 1 family member), encodes a novel embryonic stem cell (ESC)-related protein involved in pluripotency and self-renewal of ESCs. L1TD1 is still poorly characterized and its expression pattern and function in cancer cells are virtually unknown. Although normally restricted to non-neoplastic undifferentiated cells and germ cells, we found that high L1TD1 expression also occurs in medulloblastoma cells, reaching levels similar to those found in ESCs, and is correlated with poor prognosis. Conversely to what is reported during normal cell differentiation, when differentiated cells remain healthy, despite L1TD1 downregulation, depletion of L1TD1 protein levels by targeted gene silencing significantly reduced medulloblastoma cell viability, inhibiting cell proliferation and inducing apoptosis. More strikingly, L1TD1 depletion downregulated expression of the neural stem cell markers, CD133 and Nestin, inhibited neurosphere generation capability, and sensitized medulloblastoma cells to temozolomide and cisplatin, two chemotherapeutic agents of clinical relevance in medulloblastoma treatment. Our findings provide insights about the contribution of pluripotency-related genes to a more aggressive tumor phenotype through their involvement in the acquisition of stem-like properties by cancer cells and point out L1TD1 as a potential therapeutic target in malignant brain tumors.
Leyme A, etal., J Biol Chem. 2016 Apr 8;291(15):8269-82. doi: 10.1074/jbc.M115.691550. Epub 2016 Feb 17.
Activation of the tyrosine kinase focal adhesion kinase (FAK) upon cell stimulation by the extracellular matrix initiates integrin outside-in signaling. FAK is directly recruited to active integrins, which enhances its kinase activity and triggers downstream signaling like activation of PI3K. We re
cently described that Galpha-interacting, vesicle-associated protein (GIV), a protein up-regulated in metastatic cancers, is also required for outside-in integrin signaling. More specifically, we found that GIV is a non-receptor guanine nucleotide exchange factor that activates trimeric G proteins in response to integrin stimulation to enhance PI3K signaling and tumor cell migration. In contrast, previous reports have established that GIV is involved in phosphotyrosine (Tyr(P))-based signaling in response to growth factor stimulation;i.e.GIV phosphorylation at Tyr-1764 and Tyr-1798 recruits and activates PI3K. Here we show that phosphorylation of GIV at Tyr-1764/Tyr-1798 is also required to enhance PI3K-Akt signaling and tumor cell migration in response to integrin stimulation, indicating that GIV functions in Tyr(P)-dependent integrin signaling. Unexpectedly, we found that activation of FAK, an upstream component of the integrin Tyr(P) signaling cascade, was diminished in GIV-depleted cells, suggesting that GIV is required to establish a positive feedback loop that enhances integrin-FAK signaling. Mechanistically, we demonstrate that this feedback activation of FAK depends on both guanine nucleotide exchange factor and Tyr(P) GIV signaling as well as on their convergence point, PI3K. Taken together, our results provide novel mechanistic insights into how GIV promotes proinvasive cancer cell behavior by working as a signal-amplifying platform at the crossroads of trimeric G protein and Tyr(P) signaling.
Gupta V, etal., Proc Natl Acad Sci U S A. 2016 Sep 27;113(39):E5721-30. doi: 10.1073/pnas.1609502113. Epub 2016 Sep 12.
We previously showed that guanine nucleotide-binding (G) protein α subunit (Gα)-interacting vesicle-associated protein (GIV), a guanine-nucleotide exchange factor (GEF), transactivates Gα activity-inhibiting polypeptide 1 (Gαi) proteins in response to growth factors, such as
EGF, using a short C-terminal motif. Subsequent work demonstrated that GIV also binds Gαs and that inactive Gαs promotes maturation of endosomes and shuts down mitogenic MAPK-ERK1/2 signals from endosomes. However, the mechanism and consequences of dual coupling of GIV to two G proteins, Gαi and Gαs, remained unknown. Here we report that GIV is a bifunctional modulator of G proteins; it serves as a guanine nucleotide dissociation inhibitor (GDI) for Gαs using the same motif that allows it to serve as a GEF for Gαi. Upon EGF stimulation, GIV modulates Gαi and Gαs sequentially: first, a key phosphomodification favors the assembly of GIV-Gαi complexes and activates GIV's GEF function; then a second phosphomodification terminates GIV's GEF function, triggers the assembly of GIV-Gαs complexes, and activates GIV's GDI function. By comparing WT and GIV mutants, we demonstrate that GIV inhibits Gαs activity in cells responding to EGF. Consequently, the cAMP->PKA->cAMP response element-binding protein signaling axis is inhibited, the transit time of EGF receptor through early endosomes are accelerated, mitogenic MAPK-ERK1/2 signals are rapidly terminated, and proliferation is suppressed. These insights define a paradigm in G-protein signaling in which a pleiotropically acting modulator uses the same motif both to activate and to inhibit G proteins. Our findings also illuminate how such modulation of two opposing Gα proteins integrates downstream signals and cellular responses.
Audemard-Verger A, etal., PLoS One. 2016 Mar 22;11(3):e0151696. doi: 10.1371/journal.pone.0151696. eCollection 2016.
OBJECTIVE: To investigate association between genetic polymorphisms of GST, CYP and renal outcome or occurrence of adverse drug reactions (ADRs) in lupus nephritis (LN) treated with cyclophosphamide (CYC). CYC, as a pro-drug, requires bioactivation through multiple hepatic cytochrome P450s and glut
athione S transferases (GST). METHODS: We carried out a multicentric retrospective study including 70 patients with proliferative LN treated with CYC. Patients were genotyped for polymorphisms of the CYP2B6, CYP2C19, GSTP1, GSTM1 and GSTT1 genes. Complete remission (CR) was defined as proteinuria =0.33g/day and serum creatinine =124 micromol/l. Partial remission (PR) was defined as proteinuria =1.5g/day with a 50% decrease of the baseline proteinuria value and serum creatinine no greater than 25% above baseline. RESULTS: Most patients were women (84%) and 77% were Caucasian. The mean age at LN diagnosis was 41 +/- 10 years. The frequency of patients carrying the GST null genotype GSTT1-, GSTM1-, and the Ile-->105Val GSTP1 genotype were respectively 38%, 60% and 44%. In multivariate analysis, the Ile-->105Val GSTP1 genotype was an independent factor of poor renal outcome (achievement of CR or PR) (OR = 5.01 95% CI [1.02-24.51]) and the sole factor that influenced occurrence of ADRs was the GSTM1 null genotype (OR = 3.34 95% CI [1.064-10.58]). No association between polymorphisms of cytochrome P450s gene and efficacy or ADRs was observed. CONCLUSION: This study suggests that GST polymorphisms highly impact renal outcome and occurrence of ADRs related to CYC in LN patients.
OBJECTIVES: The aim of this study was to assess the effect of a weight loss treatment on obesity- associated variables with respect to the CLOCK and FTO genotypes. METHODS: In all, 179 volunteers (78% female) participated in a 12-week calorie-restriction program; hypocaloric die
ts of between 5442 and 10048 kJ/d were individually prescribed to all participants. Dietetic, anthropometric, and biochemical data were collected at baseline and at the end of the intervention. When treatment was over, five single nucleotide polymorphisms (SNPs) were sought in CLOCK and FTO in all participants who provided consent. Bonferroni-corrected linear regression models were used to examine the influence of interactions of the type genotype × dietetic change on obesity-associated variables. RESULTS: Variation in the CLOCK and FTO genotypes had no significant influence on the change in obesity-associated variables. The interaction genotype × percentage intake of dietary fat had a significant influence on body mass index (BMI; adjusted P = 0.03). Participants carrying CLOCK rs3749474 (TT + CT) showed a positive association between the change in percentage intake of dietary fat and change in BMI (ß = 0.044; 95% confidence interval [CI], 0.0119-0.0769; P = 0.008), whereas participants homozygous for the wild-type allele (CC) showed a negative, although nonsignificant association (ß = -0.032; 95% CI, -0.0694 to 0.036; P = 0.077). CONCLUSION: The possession of CLOCK rs3749474 may influence the effect of reducing the percentage intake of dietary fat on obesity-associated variables. Participants carrying this SNP might benefit more than others from weight loss treatment involving dietary fat restriction. The treatment of obesity might therefore be customized, depending on the alleles carried.
BACKGROUND AND OBJECTIVES: Advagraf is a new extended-release once-daily formulation of tacrolimus, a potent immunosuppressant widely used in renal transplantation. The aims of his study were (i) to develop a population pharmacokinetic model for once-daily tacrolimus in adult renal transplant patien
ts; and (ii) to develop a Bayesian estimator able to reliably estimate individual pharmacokinetic parameters and exposure indices. METHODS: Full pharmacokinetic profiles obtained from 41 adult renal transplant patients who had been switched from ciclosporin to a single daily dose of the new once-daily tacrolimus formulation for more than 6 months were analysed. Tacrolimus concentrations were measured using validated turbulent flow chromatography-tandem mass spectrometry methods. Population parameters were computed using nonlinear mixed-effect modelling software (NONMEM Version VI). The patients were randomly divided into (i) a model-building test group (n = 29); and (ii) a validation group (n = 12). Population pharmacokinetic analysis was performed to estimate the effects on tacrolimus pharmacokinetics of demographic characteristics (sex, bodyweight, age), drug interaction with prednisolone, laboratory test results (the haematocrit, haemaglobin level and serum creatinine level) and cytochrome P450 (CYP) 3A5 (CYP3A5) genetic polymorphism. The population pharmacokinetic model was further refined by taking into account all of the data from the 41 patients, and the final model was validated using a bootstrap and a visual predictive check. For Bayesian estimation, the best limited-sampling strategy was determined on the basis of the D-optimality criterion and validation performed in the validation group. RESULTS: The trapezoidal area under the whole-blood concentration time curve from 0 to 24 hours (AUC(24)) of tacrolimus varied by up to 50% for the same trough concentration value. The pharmacokinetics of once-daily tacrolimus were well described by a two-compartment model combined with an Erlang distribution to describe the absorption phase. The CYP3A5 genotype was the only covariate retained in the final model. The apparent clearance of tacrolimus was 2-fold higher in expressers (with the CYP3A5*1/*1 and CYP3A5*1/*3 genotypes) than in non-expressers (with the CYP3A5*3/*3 genotype). This factor explained around 25% of the interindividual variability in the apparent clearance. A posteriori Bayesian estimation allowed accurate prediction of the AUC(24) of once-daily tacrolimus, using just three sampling times (0, 1 and 3 hours post-dose) with a nonsignificant mean bias of 0.7% (range 16-20%) and good precision (root mean square error 9%). CONCLUSIONS: Population pharmacokinetic analysis of once-daily tacrolimus in renal transplant recipients resulted in identification of the CYP3A5*1/*3 genotype as a significant covariate on the apparent clearance of tacrolimus, and the design of an accurate maximum a posteriori Bayesian estimator based on three blood concentration measurements and this covariate. Such a tool could be helpful for comparing different exposure indices or different target levels. It could contribute to improvement of the efficacy and tolerability of once-daily tacrolimus in some patients.
López-Sánchez I, etal., Proc Natl Acad Sci U S A. 2013 Apr 2;110(14):5510-5. doi: 10.1073/pnas.1303392110. Epub 2013 Mar 18.
Gα-interacting, vesicle-associated protein (GIV/Girdin) is a multidomain signal transducer that enhances PI3K-Akt signals downstream of both G-protein-coupled receptors and growth factor receptor tyrosine kinases during diverse biological processes and cancer metastasis. Mechanistically, GIV s
erves as a non-receptor guanine nucleotide exchange factor (GEF) that enhances PI3K signals by activating trimeric G proteins, Gαi1/2/3. Site-directed mutations in GIV's GEF motif disrupt its ability to bind or activate Gi and abrogate PI3K-Akt signals; however, nothing is known about how GIV's GEF function is regulated. Here we report that PKCθ, a novel protein kinase C, down-regulates GIV's GEF function by phosphorylating Ser(S)1689 located within GIV's GEF motif. We demonstrate that PKCθ specifically binds and phosphorylates GIV at S1689, and this phosphoevent abolishes GIV's ability to bind and activate Gαi. HeLa cells stably expressing the phosphomimetic mutant of GIV, GIV-S1689->D, are phenotypically identical to those expressing the GEF-deficient F1685A mutant: Actin stress fibers are decreased and cell migration is inhibited whereas cell proliferation is triggered, and Akt (a.k.a. protein kinase B, PKB) activation is impaired downstream of both the lysophosphatidic acid receptor, a G-protein-coupled receptor, and the insulin receptor, a receptor tyrosine kinase. These findings indicate that phosphorylation of GIV by PKCθ inhibits GIV's GEF function and generates a unique negative feedback loop for downregulating the GIV-Gi axis of prometastatic signaling downstream of multiple ligand-activated receptors. This phosphoevent constitutes the only regulatory pathway described for terminating signaling by any of the growing family of nonreceptor GEFs that modulate G-protein activity.
Hepatitis C virus (HCV) enters human hepatocytes through a multistep mechanism involving, among other host proteins, the virus receptor CD81. How CD81 governs HCV entry is poorly characterized, and CD81 protein interactions after virus binding remain elusive. We have developed a quantitative proteom
ics protocol to identify HCV-triggered CD81 interactions and found 26 dynamic binding partners. At least six of these proteins promote HCV infection, as indicated by RNAi. We further characterized serum response factor binding protein 1 (SRFBP1), which is recruited to CD81 during HCV uptake and supports HCV infection in hepatoma cells and primary human hepatocytes. SRFBP1 facilitates host cell penetration by all seven HCV genotypes, but not of vesicular stomatitis virus and human coronavirus. Thus, SRFBP1 is an HCV-specific, pan-genotypic host entry factor. These results demonstrate the use of quantitative proteomics to elucidate pathogen entry and underscore the importance of host protein-protein interactions during HCV invasion.
Ramanathan A, etal., Nucleic Acids Res. 2016 Jan 29;44(2):896-909. doi: 10.1093/nar/gkv1299. Epub 2015 Nov 26.
RIG-I (Retinoic Acid Inducible Gene-I) is a cytosolic innate immune receptor that detects atypical features in viral RNAs as foreign to initiate a Type I interferon signaling response. RIG-I is present in an autoinhibited state in the cytoplasm and activated by blunt-ended double-stranded (ds)RNAs
carrying a 5' triphosphate (ppp) moiety. These features found in many pathogenic RNAs are absent in cellular RNAs due to post-transcriptional modifications of RNA ends. Although RIG-I is structurally well characterized, the mechanistic basis for RIG-I's remarkable ability to discriminate between cellular and pathogenic RNAs is not completely understood. We show that RIG-I's selectivity for blunt-ended 5'-ppp dsRNAs is approximately 3000 times higher than non-blunt ended dsRNAs commonly found in cellular RNAs. Discrimination occurs at multiple stages and signaling RNAs have high affinity and ATPase turnover rate and thus a high katpase/Kd. We show that RIG-I uses its autoinhibitory CARD2-Hel2i (second CARD-helicase insertion domain) interface as a barrier to select against non-blunt ended dsRNAs. Accordingly, deletion of CARDs or point mutations in the CARD2-Hel2i interface decreases the selectivity from approximately 3000 to 150 and 750, respectively. We propose that the CARD2-Hel2i interface is a 'gate' that prevents cellular RNAs from generating productive complexes that can signal.
Cornelia de Lange syndrome (CdLS) is characterized by facial dysmorphism, growth failure, intellectual disability, limb malformations, and multiple organ involvement. Mutations in five genes, encoding subunits of the cohesin complex (SMC1A, SMC3, RAD21) and its regulators (NIPBL, HDAC8), account for
at least 70% of patients with CdLS or CdLS-like phenotypes. To date, only the clinical features from a single CdLS patient with SMC3 mutation has been published. Here, we report the efforts of an international research and clinical collaboration to provide clinical comparison of 16 patients with CdLS-like features caused by mutations in SMC3. Modeling of the mutation effects on protein structure suggests a dominant-negative effect on the multimeric cohesin complex. When compared with typical CdLS, many SMC3-associated phenotypes are also characterized by postnatal microcephaly but with a less distinctive craniofacial appearance, a milder prenatal growth retardation that worsens in childhood, few congenital heart defects, and an absence of limb deficiencies. While most mutations are unique, two unrelated affected individuals shared the same mutation but presented with different phenotypes. This work confirms that de novo SMC3 mutations account for ∼ 1%-2% of CdLS-like phenotypes.
Fernandez-Alonso R, etal., Cell Death Differ. 2015 Aug;22(8):1287-99. doi: 10.1038/cdd.2014.214. Epub 2015 Jan 9.
Vasculogenesis, the establishment of the vascular plexus and angiogenesis, branching of new vessels from the preexisting vasculature, involves coordinated endothelial differentiation, proliferation and migration. Disturbances in these coordinated processes may accompany diseases such as cancer. We h
ypothesized that the p53 family member p73, which regulates cell differentiation in several contexts, may be important in vascular development. We demonstrate that p73 deficiency perturbed vascular development in the mouse retina, decreasing vascular branching, density and stability. Furthermore, p73 deficiency could affect non endothelial cells (ECs) resulting in reduced in vivo proangiogenic milieu. Moreover, p73 functional inhibition, as well as p73 deficiency, hindered vessel sprouting, tubulogenesis and the assembly of vascular structures in mouse embryonic stem cell and induced pluripotent stem cell cultures. Therefore, p73 is necessary for EC biology and vasculogenesis and, in particular, that DNp73 regulates EC migration and tube formation capacity by regulation of expression of pro-angiogenic factors such as transforming growth factor-beta and vascular endothelial growth factors. DNp73 expression is upregulated in the tumor environment, resulting in enhanced angiogenic potential of B16-F10 melanoma cells. Our results demonstrate, by the first time, that differential p73-isoform regulation is necessary for physiological vasculogenesis and angiogenesis and DNp73 overexpression becomes a positive advantage for tumor progression due to its pro-angiogenic capacity.
Damgaard RB, etal., Cell. 2016 Aug 25;166(5):1215-1230.e20. doi: 10.1016/j.cell.2016.07.019. Epub 2016 Aug 11.
Methionine-1 (M1)-linked ubiquitin chains regulate the activity of NF-kappaB, immune homeostasis, and responses to infection. The importance of negative regulators of M1-linked chains in vivo remains poorly understood. Here, we show that the M1-specific deubiquitinase OTULIN is essential for prevent
ing TNF-associated systemic inflammation in humans and mice. A homozygous hypomorphic mutation in human OTULIN causes a potentially fatal autoinflammatory condition termed OTULIN-related autoinflammatory syndrome (ORAS). Four independent OTULIN mouse models reveal that OTULIN deficiency in immune cells results in cell-type-specific effects, ranging from over-production of inflammatory cytokines and autoimmunity due to accumulation of M1-linked polyubiquitin and spontaneous NF-kappaB activation in myeloid cells to downregulation of M1-polyubiquitin signaling by degradation of LUBAC in B and T cells. Remarkably, treatment with anti-TNF neutralizing antibodies ameliorates inflammation in ORAS patients and rescues mouse phenotypes. Hence, OTULIN is critical for restraining life-threatening spontaneous inflammation and maintaining immune homeostasis.
BACKGROUND: The condition known as cachexia presents in most patients with malignant tumours, leading to a poor quality of life and premature death. Although the cancer-cachexia state primarily affects skeletal muscle, possible damage in the cardiac muscle remains to be better characterized and eluc
idated. Leucine, which is a branched chain amino acid, is very useful for preserving lean body mass. Thus, this amino acid has been studied as a coadjuvant therapy in cachectic cancer patients, but whether this treatment attenuates the effects of cachexia and improves cardiac function remains poorly understood. Therefore, using an experimental cancer-cachexia model, we evaluated whether leucine supplementation ameliorates cachexia in the heart. METHODS: Male Wistar rats were fed either a leucine-rich or a normoprotein diet and implanted or not with subcutaneous Walker-256 carcinoma. During the cachectic stage (approximately 21 days after tumour implantation), when the tumour mass was greater than 10% of body weight, the rats were subjected to an electrocardiogram analysis to evaluate the heart rate, QT-c, and T wave amplitude. The myocardial tissues were assayed for proteolytic enzymes (chymotrypsin, alkaline phosphatase, cathepsin, and calpain), cardiomyopathy biomarkers (myeloperoxidase, tissue inhibitor of metalloproteinases, and total plasminogen activator inhibitor 1), and caspase-8, -9, -3, and -7 activity. RESULTS: Both groups of tumour-bearing rats, especially the untreated group, had electrocardiography alterations that were suggestive of ischemia, dilated cardiomyopathy, and sudden death risk. Additionally, the rats in the untreated tumour-bearing group but not their leucine-supplemented littermates exhibited remarkable increases in chymotrypsin activity and all three heart failure biomarkers analysed, including an increase in caspase-3 and -7 activity. CONCLUSIONS: Our data suggest that a leucine-rich diet could modulate heart damage, cardiomyocyte proteolysis, and apoptosis driven by cancer-cachexia. Further studies must be conducted to elucidate leucine's mechanisms of action, which potentially includes the modulation of the heart's inflammatory process.
NBS1 is an early component in DNA-Damage Response (DDR) that participates in the initiation of the responses aiming to repair double-strand breaks caused by different mechanisms. Early steps in DDR have to react to local alterations in chromatin that are induced by DNA damage. NBS1 participates in
the early detection of DNA damage and functions as a platform for the recruitment and assembly of components that are sequentially required for the repair process. In this work we have studied whether the VRK1 chromatin kinase can affect the activation of NBS1 in response to DNA damage induced by ionizing radiation. VRK1 is forming a basal preassembled complex with NBS1 in non-damaged cells. Knockdown of VRK1 resulted in the loss of NBS1 foci induced by ionizing radiation, an effect that was also detected in cell-cycle arrested cells and in ATM (-/-) cells. The phosphorylation of NBS1 in Ser343 by VRK1 is induced by either doxorubicin or IR in ATM (-/-) cells. Phosphorylated NBS1 is also complexed with VRK1. NBS1 phosphorylation by VRK1 cooperates with ATM. This phosphorylation of NBS1 by VRK1 contributes to the stability of NBS1 in ATM (-/-) cells, and the consequence of its loss can be prevented by treatment with the MG132 proteasome inhibitor of RNF8. We conclude that VRK1 regulation of NBS1 contributes to the stability of the repair complex and permits the sequential steps in DDR.
Patients with advanced Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutant lung adenocarcinoma are currently treated with standard chemotherapy because of a lack of efficacious targeted therapies. We reasoned that the identification of mediators of Kras signaling in early mouse lung hyperplasia
s might bypass the difficulties that are imposed by intratumor heterogeneity in advanced tumors, and that it might unveil relevant therapeutic targets. Transcriptional profiling of Kras(G12V)-driven mouse hyperplasias revealed intertumor diversity with a subset that exhibited an aggressive transcriptional profile analogous to that of advanced human adenocarcinomas. The top-scoring gene in this profile encodes the tyrosine kinase receptor DDR1. The genetic and pharmacological inhibition of DDR1 blocked tumor initiation and tumor progression, respectively. The concomitant inhibition of both DDR1 and Notch signaling induced the regression of KRAS;TP53-mutant patient-derived lung xenografts (PDX) with a therapeutic efficacy that was at least comparable to that of standard chemotherapy. Our data indicate that the combined inhibition of DDR1 and Notch signaling could be an effective targeted therapy for patients with KRAS-mutant lung adenocarcinoma.
Nobrega-Pereira S, etal., Nat Commun. 2016 Mar 15;7:10894. doi: 10.1038/ncomms10894.
Reactive oxygen species (ROS) are constantly generated by cells and ROS-derived damage contributes to ageing. Protection against oxidative damage largely relies on the reductive power of NAPDH, whose levels are mostly determined by the enzyme glucose-6-phosphate dehydrogenase (G6PD). Here, we repor
t a transgenic mouse model with moderate overexpression of human G6PD under its endogenous promoter. Importantly, G6PD-Tg mice have higher levels of NADPH, lower levels of ROS-derived damage, and better protection from ageing-associated functional decline, including extended median lifespan in females. The G6PD transgene has no effect on tumour development, even after combining with various tumour-prone genetic alterations. We conclude that a modest increase in G6PD activity is beneficial for healthspan through increased NADPH levels and protection from the deleterious effects of ROS.
Teresa-Rodrigo ME, etal., Biomed Res Int. 2016;2016:8742939. doi: 10.1155/2016/8742939. Epub 2016 Jan 26.
Cornelia de Lange syndrome (CdLS) is a rare genetically heterogeneous disorder with a high phenotypic variability including mental retardation, developmental delay, and limb malformations. The genetic causes in about 30% of patients with CdLS are still unknown. We report on the functional characteri
zation of two intronic NIPBL mutations in two patients with CdLS that do not affect a conserved splice-donor or acceptor site. Interestingly, mRNA analyses showed aberrantly spliced transcripts missing exon 28 or 37, suggesting the loss of the branch site by the c.5329-15A>G transition and a disruption of the polypyrimidine by the c.6344del(-13)_(-8) deletion. While the loss of exon 28 retains the reading frame of the NIBPL transcript resulting in a shortened protein, the loss of exon 37 shifts the reading frame with the consequence of a premature stop of translation. Subsequent quantitative PCR analysis demonstrated a 30% decrease of the total NIPBL mRNA levels associated with the frameshift transcript. Consistent with our results, this patient shows a more severe phenotype compared to the patient with the aberrant transcript that retains its reading frame. Thus, intronic variants identified by sequencing analysis in CdLS diagnostics should carefully be examined before excluding them as nonrelevant to disease.
Cioffi M, etal., Cell Rep. 2015 Sep 8;12(10):1594-605. doi: 10.1016/j.celrep.2015.08.006. Epub 2015 Aug 28.
Conquering obesity has become a major socioeconomic challenge. Here, we show that reduced expression of the miR-25-93-106b cluster, or miR-93 alone, increases fat mass and, subsequently, insulin resistance. Mechanistically, we discovered an intricate interplay between enhanced adipocyte precursor t
urnover and increased adipogenesis. First, miR-93 controls Tbx3, thereby limiting self-renewal in early adipocyte precursors. Second, miR-93 inhibits the metabolic target Sirt7, which we identified as a major driver of in vivo adipogenesis via induction of differentiation and maturation of early adipocyte precursors. Using mouse parabiosis, obesity in mir-25-93-106b(-/-) mice could be rescued by restoring levels of circulating miRNA and subsequent inhibition of Tbx3 and Sirt7. Downregulation of miR-93 also occurred in obese ob/ob mice, and this phenocopy of mir-25-93-106b(-/-) was partially reversible with injection of miR-93 mimics. Our data establish miR-93 as a negative regulator of adipogenesis and a potential therapeutic option for obesity and the metabolic syndrome.
Mutations in the charged multivesicular body protein 2B (CHMP2B) gene cause frontotemporal lobar degeneration. The mutations lead to C-terminal truncation of the CHMP2B protein. We generated Chmp2b knockout mice and transgenic mice expressing either wild-type or C-terminally truncated mutant CHMP2B.
The transgenic CHMP2B mutant mice have decreased survival and show progressive neurodegenerative changes including gliosis and increasing accumulation of p62- and ubiquitin-positive inclusions. The inclusions are negative for the TAR DNA binding protein 43 and fused in sarcoma proteins, mimicking the inclusions observed in patients with CHMP2B mutation. Mice transgenic for mutant CHMP2B also develop an early and progressive axonopathy characterized by numerous amyloid precursor protein-positive axonal swellings, implicating altered axonal function in disease pathogenesis. These findings were not observed in Chmp2b knockout mice or in transgenic mice expressing wild-type CHMP2B, indicating that CHMP2B mutations induce degenerative changes through a gain of function mechanism. These data describe the first mouse model of dementia caused by CHMP2B mutation and provide new insights into the mechanisms of CHMP2B-induced neurodegeneration.
Prion infections, causing neurodegenerative conditions such as Creutzfeldt-Jakob disease and kuru in humans, scrapie in sheep and BSE in cattle are characterised by prolonged and variable incubation periods that are faithfully reproduced in mouse models. Incubation time is partly determined by genet
ic factors including polymorphisms in the prion protein gene. Quantitative trait loci studies in mice and human genome-wide association studies have confirmed that multiple genes are involved. Candidate gene approaches have also been used and identified App, Il1-r1 and Sod1 as affecting incubation times. In this study we looked for an association between App, Il1-r1 and Sod1 representative SNPs and prion disease incubation time in the Northport heterogeneous stock of mice inoculated with the Chandler/RML prion strain. No association was seen with App, however, significant associations were seen with Il1-r1 (P = 0.02) and Sod1 (P<0.0001) suggesting that polymorphisms at these loci contribute to the natural variation observed in incubation time. Furthermore, following challenge with Chandler/RML, ME7 and MRC2 prion strains, Sod1 deficient mice showed highly significant reductions in incubation time of 20, 13 and 24%, respectively. No differences were detected in Sod1 expression or activity. Our data confirm the protective role of endogenous Sod1 in prion disease.
de Juan-Marcos L, etal., Ophthalmic Genet. 2016;37(1):25-30. doi: 10.3109/13816810.2014.921316. Epub 2014 Jun 3.
PURPOSE: To evaluate the association of the lysyl oxidase-like 1 (LOXL1) single nucleotide polymorphisms (SNPs) in a Spanish population with pseudoexfoliation syndrome (XFS) and pseudoexfoliation glaucoma (XFG). MATERIALS AND METHODS: The present case-control study included 100 Spanish patients (60
patients with XFS and 40 patients with XFG) and 90 control subjects. Genotypes of the three single nucleotide polymorphisms of LOXL1 (rs1048661, rs3825942, and rs2165241) were analyzed with direct sequencing. RESULTS: The G allele and the GG genotype of SNP rs3825942 were detected at a statistically higher frequency in pseudoexfoliation patients than in control subjects (p = 3.36 x 10(-5), OR = 5.71, 95% CI: 2.30-14.18; p = 3.38 x 10(-5), OR = 6.91, 95% CI: 2.51-19.03 respectively). The T allele and the TT genotype of SNP rs2165241 presented at significantly higher frequencies in pseudoexfoliation patients than in controls (p = 2.50 x 10(-4), OR = 2.18, 95% CI: 1.43-3.33; p = 1.21 x 10(-2), OR = 2.13, 95% CI: 1.75-3.85 respectively). No significant association between XFS/XFG and the rs1048661 was observed. The GGT haplotype composed of all three risk alleles was determined to be significantly associated with pseudoexfoliation. The genotypic and allelic distributions of the three SNPs were similar between XFS and XFG. CONCLUSIONS: This is the first study associating two SNPs of LOXL1 (rs3825942 and rs2165241) and XFS/XFG in a Spanish population, confirming findings in patients from Europe. However rs1048661 SNP did not show an association with XFS.
Ohta M, etal., Medicine (Baltimore). 2016 Feb;95(7):e2853. doi: 10.1097/MD.0000000000002853.
IgG4-related disease (IgG4-RD) is a novel systemic disease entity characterized by elevated serum IgG4 and tissue infiltration of IgG4-positive plasma cells accompanied by severe fibrosis. Although recent studies demonstrated that innate immune cells including monocytes and macrophages might promot
e local fibrosis and IgG4 production, the pathological mechanism remains unclear. In this study, we sought to identify the disease-associated genes, especially innate immune molecules. Gene expression was analyzed by DNA microarray in submandibular glands (SMGs) from patients with IgG4-RD (n = 5), chronic sialoadenitis (CS) (n = 3), and controls (n = 3). Differentially expressed genes (DEGs) were validated by real-time polymerase chain reaction (PCR) and immunohistochemical staining in IgG4-RD (n = 18), CS (n = 4), Sjogren syndrome (n = 11), and controls (n = 10). Gene expression patterns in the 3 groups were quite different from each other by the pvclust method and principal components analysis. In IgG4-RD, 1028 upregulated genes and 692 downregulated genes were identified as DEGs (P < 0.05). Gene Ontology (GO) term analysis indicated that the upregulated DEGs in IgG4-RD encoded proteins involved in T/B cell activation and chemotaxis. PCR validated significantly higher expression of macrophage receptor with collagenous structure (MARCO), a pattern-recognition receptor, in IgG4-RD compared with the other groups (P < 0.01). Immunohistochemical analysis confirmed that the expression pattern of MARCO was similar to that of the M2 macrophage marker CD163. MARCO was identified as a disease-associated molecule in IgG4-RD by DNA microarray. Moreover, M2 macrophages might contribute to the initiation of IgG4-RD via MARCO.
BACKGROUND: Gene polymorphisms impact greatly on a person's susceptibility to pulmonary tuberculosis (PTB). Macrophage receptor with collagenous structure (MARCO) and CD36 are two scavenger receptors (SRs) that can recognize Mycobacterium tuberculosis
(Mtb) and play a key role in tuberculosis infection. Gene polymorphisms of MARCO and CD36 may contribute to tuberculosis risk. METHODS: To investigate whether genetic polymorphisms of MARCO and CD36 are associated with susceptibility to PTB, genomic DNA samples from patients (n = 202) and healthy controls (n = 216) were collected and analyzed by polymerase chain reaction with high-resolution melting analysis. RESULTS: We studied two single nucleotide polymorphisms (SNPs) in MARCO (rs12998782 and rs17009726) and three SNPs in CD36 (rs1194182, rs3211956 and rs10499859). Rs12998782 (P = 0.018) might be associated with susceptibility to PTB. Rs1194182 (P < 0.01) and rs10499859 (P < 0.001) might be associated with resistance to PTB. Rs17009726 and rs3211956 were not associated with susceptibility/resistance to PTB. CONCLUSIONS: These data showed that MARCO rs12998782 may increase PTB risk while two SNPs of CD36, rs1194182 and rs10499859 may reduce the risk, indicating MARCO and CD36 as important receptors in response to PTB.
Recent studies suggest that the chemotactic G protein-coupled receptor formyl-peptide-receptor-like-1 (FPRL1) or the scavenger receptor MARCO (macrophage receptor with collagenous structure) plays an essential role in the inflammatory response of host defense me
chanisms and neurodegenerative disorders such as Alzheimer's disease. We therefore analyzed the involvement of FPRL1 and MARCO in amyloid beta1-42 (Abeta1-42)-induced signalling by extracellular-signal regulated kinases 1/2 (ERK1/2) phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia) and in transfected HEK293 cells. Receptors were inhibited by small interference RNA and the consequences in Abeta1-42- and MARCO agonist fucoidan-induced signal transduction were determined. Receptor deactivation by antagonists or small interference RNA verified the importance of FPRL1 for Abeta1-42-mediated signal transduction by ERK1/2 phosphorylation and cAMP level measurement in glial cells. Furthermore, for the first time, we have demonstrated a functional interaction between FPRL1 and scavenger receptors in fucoidan-mediated signalling by ERK1/2 phosphorylation and cAMP level measurement. In addition, co-immunoprecipitation data and fluorescence microscopy measurements revealed a physical interaction between FPR, FPRL1 and MARCO. These results suggest that FPRL1 plays a pivotal role for Abeta1-42-induced signal transduction in glial cells and the interaction with MARCO could explain the broad ligand spectrum of formyl peptide receptors.
BACKGROUND: The two major class A scavenger receptors are scavenger receptor A (SRA), which is constitutively expressed on most macrophage populations, and macrophage receptor with collagenous structure (MARCO), which is constitutively expressed on a
more restricted subset of macrophages, (e.g. alveolar macrophages) but whose expression increases on most macrophages during the course of infection. Although the primary role of SRA appears to be clearance of modified host proteins and lipids, mice defective in expression of either MARCO or SRA are immunocompromised in multiple models of infection and in vitro assays, the scavenger receptors have been demonstrated to bind bacteria and to enhance pro-inflammatory signalling to many bacterial lung pathogens; however their importance in Mycobacterium tuberculosis infection, is less clear. METHODS: To determine whether polymorphisms in either SRA or MARCO were associated with tuberculosis, a case-control study of was performed. DNA samples from newly-detected, smear-positive, pulmonary tuberculosis cases were collected from The Gambia. Controls for this study consisted of DNA from cord bloods obtained from routine births at local Gambian health clinics. Informed written consent was obtained from patients or their parents or guardians. Ethical approval was provided by the joint The Gambian Government/MRC Joint Ethics Committee. RESULTS: We studied the frequencies of 25 polymorphisms of MSR1 (SRA) and 22 in MARCO in individuals with tuberculosis (n=1284) and matched controls (n=1349). No SNPs within the gene encoding or within 1 kb of the promoter sequence of MSR1 were associated with either susceptibility or resistance to tuberculosis. Three SNPs in MARCO (rs4491733, Mantel-Haenszel 2x2 χ2 = 6.5, p = 0.001, rs12998782, Mantel-Haenszel 2x2 χ2 = 6.59, p = 0.001, rs13389814 Mantel-Haenszel 2x2 χ2 = 6.9, p = 0.0009) were associated with susceptibility to tuberculosis and one (rs7559955, Mantel-Haenszel 2x2 χ2 = 6.9, p = 0.0009) was associated with resistance to tuberculosis. CONCLUSIONS: These findings identify MARCO as a potentially important receptor in the host response to tuberculosis.
BACKGROUND: The accumulation of soluble oligomeric amyloid-beta peptide (oAbeta) proceeding the formation of senile plaques contributes to synaptic and memory deficits in Alzheimer's disease. Our previous studies have indentified scavenger receptor A (SR-A), especially SR-A type I (SR-AI), as prom
inent scavenger receptors on mediating oAbeta clearance by microglia while glycan moiety and scavenger receptor cysteine-rich (SRCR) domain may play the critical role. Macrophage receptor with collagenous structure (MARCO), another member of class A superfamily with a highly conserved SRCR domain, may also play the similar role on oAbeta internalization. However, the role of N-glycosylation and SRCR domain of SR-AI and MARCO on oAbeta internalization remains unclear. RESULT: We found that oAbeta internalization was diminished in the cells expressing SR-AI harboring mutations of dual N-glycosylation sites (i.e. N120Q-N143Q and N143Q-N184Q) while they were normally surface targeted. Normal oAbeta internalization was observed in 10 SR-AI-SRCR and 4 MARCO-SRCR surface targeted mutants. Alternatively, the SRCR mutants at beta-sheet and alpha-helix and on disulfide bone formation obstructed receptor's N-glycosylation and surface targeting. CONCLUSION: Our study reveals that N-glycan moiety is more critical than SRCR domain for SR-A-mediated oAbeta internalization.
Yang M, etal., Toxicol Lett. 2019 Feb;301:64-72. doi: 10.1016/j.toxlet.2018.10.031. Epub 2018 Nov 2.
Epithelial-mesenchymal transition (EMT) is linked to fibrosis following exposure to silica. The scavenger receptor, macrophage receptor with collagenous structure (MARCO) plays an important role in silica-induced inflammation, however, the effect of MARCO
'font-weight:700;'>MARCO on silica-induced fibrosis has not been identified. We hypothesized that MARCO would regulate EMT and be involved in the development of silicosis. Herein, we found that MARCO was highly expressed in lung tissue after exposure to silica and a MARCO inhibitor PolyG could alleviate pulmonary fibrosis in vivo. Our results confirmed that the expression of epithelial marker such as E-cadherin decreased, while the expression of mesenchymal markers, including vimentin and α-SMA increased after silica treatment. Furthermore, PolyG administration efficiently blocked the mRNA and protein expression of EMT markers and decreased the level of fibrosis-related transcription factors and proteins, such as Col1a1, Col3a1, Collagen I and Collagen III in the lungs of silica-exposed rats. The findings demonstrate that the macrophage membrane receptor MARCO controls the fibrotic response through regulating EMT in experimental silicosis and suggest a novel target for preventive intervention.
Hirano S and Kanno S, PLoS One. 2015 Nov 6;10(11):e0142062. doi: 10.1371/journal.pone.0142062. eCollection 2015.
The Macrophage Receptor with COllagenous structure (MARCO) protein is a plasma membrane receptor for un-opsonized or environmental particles on phagocytic cells. Here, we show that MARCO was internalized either by ruffling o
f plasma membrane followed by macropinocytosis or by endocytosis followed by fusion with autophagosome in CHO-K1 cells stably transfected with GFP-MARCO. The macropinocytic process generated large vesicles when the plasma membrane subsided. The endocytosis/autophagosome (amphisome) generated small fluorescent puncta which were visible in the presence of glutamine, chloroquine, bafilomycin, ammonia, and other amines. The small puncta, but not the large vesicles, co-localized with LC3B and lysosomes. The LC3-II/LC3-I ratio increased in the presence of glutamine, ammonia, and chloroquine in various cells. The small puncta trafficked between the peri-nuclear region and the distal ends of cells back and forth at rates of up to 2-3 mum/sec; tubulin, but not actin, regulated the trafficking of the small puncta. Besides phagocytosis MARCO, an adhesive plasma membrane receptor, may play a role in incorporation of various extracellular materials into the cell via both macropinocytic and endocytic pathways.
Ghosh S, etal., Am J Respir Cell Mol Biol. 2011 Nov;45(5):1036-44. doi: 10.1165/rcmb.2010-0349OC. Epub 2011 May 11.
Lung macrophages use the scavenger receptor MARCO to bind and ingest bacteria, particulate matter, and post cellular debris. We investigated the role of MARCO in influenza A virus (IAV) pneumonia. In contrast to higher susce
ptibility to bacterial infection, MARCO(-/-) mice had lower morbidity and mortality from influenza pneumonia than wild-type (WT) mice. The early course of influenza in MARCO(-/-) lungs was marked by an enhanced but transient neutrophilic inflammatory response and significantly lower viral replication compared with the WT mice. At later time points, no significant differences in lung histopathology or absolute numbers of T lymphocyte influx were evident. Uptake of IAV by WT and MARCO(-/-) bronchoalveolar lavage macrophages in vitro was similar. By LPS coadministration, we demonstrated that rapid neutrophil and monocyte influx during the onset of influenza suppressed viral replication, indicating a protective role of early inflammation. We hypothesized that the presence of increased basal proinflammatory post cellular debris in the absence of scavenging function lowered the inflammatory response threshold to IAV in MARCO(-/-) mice. Indeed, MARCO(-/-) mice showed increased accumulation of proinflammatory oxidized lipoproteins in the bronchoalveolar lavage early in the infection process, which are the potential mediators of the observed enhanced inflammation. These results indicate that MARCO suppresses a protective early inflammatory response to influenza, which modulates viral clearance and delays recovery.
Macrophage receptor with collagenous structure (MARCO) has an important role in the phagocytosis of Mycobacterium tuberculosis (M. tuberculosis). We hypothesized that MARCO polymorphisms are associated with phagocytosis, tub
erculosis (TB) disease susceptibility and presentation, and infecting lineage. We used a human cellular model to examine how MARCO genotype mediates the immune response; a case-control study to investigate tuberculosis host genetic susceptibility; and a host-pathogen genetic analysis to study host-pathogen interactions. Two MARCO heterozygous (AG) genotypes (single-nucleotide polymorphisms rs2278589 and rs6751745) were associated with impaired phagocytosis of M. tuberculosis trehalose 6,6'-dimycolate-cord factor and β-glucan-coated beads in macrophages. The heterozygous genotypes of rs2278589 and rs6751745 were also associated with increased risk of pulmonary TB (PTB; rs2278589, P=0.001, odds ratio (OR)=1.6; rs6751745, P=0.009, OR=1.4), and with severe chest X-ray abnormalities (P=0.007, OR=1.6). These two genotypes were also associated with the Beijing lineage (rs2278589, P=0.001, OR=1.7; rs6751745, P=0.01, OR=1.5). Together, these results suggest that MARCO polymorphisms may regulate phagocytosis of M. tuberculosis and susceptibility and severity of PTB. They also suggest MARCO genotype and Beijing strains may interact to increase the risk of PTB.
Xu J, etal., J Immunol. 2017 May 1;198(9):3548-3557. doi: 10.4049/jimmunol.1700057. Epub 2017 Mar 15.
The scavenger receptor macrophage receptor with collagenous structure (MARCO) promotes protective innate immunity against bacterial and parasitic infections; however, its role in host immunity against fungal pathogens, including the major human opportunistic fun
gal pathogen Cryptococcus neoformans, remains unknown. Using a mouse model of C. neoformans infection, we demonstrated that MARCO deficiency leads to impaired fungal control during the afferent phase of cryptococcal infection. Diminished fungal containment in MARCO-/- mice was accompanied by impaired recruitment of Ly6Chigh monocytes and monocyte-derived dendritic cells (moDC) and lower moDC costimulatory maturation. The reduced recruitment and activation of mononuclear phagocytes in MARCO-/- mice was linked to diminished early expression of IFN-γ along with profound suppression of CCL2 and CCL7 chemokines, providing evidence for roles of MARCO in activation of the CCR2 axis during C. neoformans infection. Lastly, we found that MARCO was involved in C. neoformans phagocytosis by resident pulmonary macrophages and DC. We conclude that MARCO facilitates early interactions between C. neoformans and lung-resident cells and promotes the production of CCR2 ligands. In turn, this contributes to a more robust recruitment and activation of moDC that opposes rapid fungal expansion during the afferent phase of cryptococcal infection.
Braun BJ, etal., J Neuroinflammation. 2011 Feb 7;8(1):11. doi: 10.1186/1742-2094-8-11.
BACKGROUND: Recent studies have suggested that the scavenger receptor MARCO (macrophage receptor with collagenous structure) mediates activation of the immune response in bacterial infection of the central nervous system (CNS). The chemotactic G-prote
in-coupled receptor (GPCR) formyl-peptide-receptor like-1 (FPRL1) plays an essential role in the inflammatory responses of host defence mechanisms and neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the antimicrobial peptide cathelicidin CRAMP/LL-37 is up-regulated in bacterial meningitis, but the mechanisms underlying CRAMP expression are far from clear. METHODS: Using a rat meningitis model, we investigated the influence of MARCO and FPRL1 on rCRAMP (rat cathelin-related antimicrobial peptide) expression after infection with bacterial supernatants of Streptococcus pneumoniae (SP) and Neisseria meningitides (NM). Expression of FPRL1 and MARCO was analyzed by immunofluorescence and real-time RT-PCR in a rat meningitis model. Furthermore, we examined the receptor involvement by real-time RT-PCR, extracellular-signal regulated kinases 1/2 (ERK1/2) phosphorylation and cAMP level measurement in glial cells (astrocytes and microglia) and transfected HEK293 cells using receptor deactivation by antagonists. Receptors were inhibited by small interference RNA and the consequences in NM- and SP-induced Camp (rCRAMP gene) expression and signal transduction were determined. RESULTS: We show an NM-induced increase of MARCO expression by immunofluorescence and real-time RT-PCR in glial and meningeal cells. Receptor deactivation by antagonists and small interfering RNA (siRNA) verified the importance of FPRL1 and MARCO for NM- and SP-induced Camp and interleukin-1β expression in glial cells. Furthermore, we demonstrated a functional interaction between FPRL1 and MARCO in NM-induced signalling by real-time RT-PCR, ERK1/2 phosphorylation and cAMP level measurement and show differences between NM- or SP-induced signal transduction. CONCLUSIONS: We propose that NM and SP induce glial cell activation and rCRAMP expression also via FPRL1 and MARCO. Thus the receptors contribute an important part to the host defence against infection.
Alveolar macrophages (AMs) express the class A scavenger receptor macrophage receptor with collagenous structure (MARCO), but its role in vivo in lung defense against bacteria and environmental particles has not been studied. We used MARCO
;'>MARCO-deficient mice to directly test the in vivo role of AM MARCO in innate defense against pneumococcal infection and environmental particles. In a murine model of pneumococcal pneumonia, MARCO(-/-) mice displayed an impaired ability to clear bacteria from the lungs, increased pulmonary inflammation and cytokine release, and diminished survival. In vitro binding of Streptococcus pneumoniae and in vivo uptake of unopsonized particles by MARCO(-/-) AMs were dramatically impaired. MARCO(-/-) mice treated with the "inert" environmental particle TiO(2) showed enhanced inflammation and chemokine expression, indicating that MARCO-mediated clearance of inert particles by AMs prevents inflammatory responses otherwise initiated by other lung cells. Our findings point to an important role of MARCO in mounting an efficient and appropriately regulated innate immune response against inhaled particles and airborne pathogens.
Santos Lacomba M, etal., Ophthalmic Res. 2001 Sep-Oct;33(5):251-5.
OBJECTIVE: To study the local and systemic behavior of the tumor necrosis factor-alpha (TNF-alpha) in patients with active uveitis. METHODS: TNF-alpha levels were measured in aqueous humor and peripheral blood samples using an enzyme-linked immunosorbent assay from 23 patients with uveitis and 16 co
ntrol patients who had been operated on for uncomplicated cataracts. RESULTS: Aqueous humor and sera of patients with uveitis showed higher levels of TNF-alpha than those of controls (p < 0.001). A comparison of cytokine levels between aqueous humor and sera showed significantly higher levels of TNF-alpha in serum than aqueous humor (p < 0.001). Correlation studies using the regression test for successive steps showed that serum TNF-alpha levels correlated with recurrent uveitis (r = 0.4150; p = 0.0489). CONCLUSIONS: TNF-alpha is a cytokine that participates actively in the pathogenesis of clinical uveitis. Our data emphasize the greater systemic than local participation of TNF-alpha. Finally, an elevated serum TNF-alpha seems to be associated with a recurrent pattern of uveitis.
Diabetic retinopathy is a leading cause of blindness. Visual function disorders have been demonstrated in diabetics even before the onset of retinopathy. At early stages of experimental diabetes, axoglial alterations occur at the distal portion of the optic nerve. Although ischemic conditioning can
protect neurons and synaptic terminals against ischemic damage, there is no information on its ability to protect axons. We analyzed the effect of ischemic conditioning on the early axoglial alterations in the distal portion of the optic nerve induced by experimental diabetes. Diabetes was induced in Wistar rats by an intraperitoneal injection of streptozotocin. Retinal ischemia was induced by increasing intraocular pressure to 120 mm Hg for 5 min; this maneuver started 3 days after streptozotocin injection and was weekly repeated in one eye, while the contralateral eye was submitted to a sham procedure. The application of ischemia pulses prevented a deficit in the anterograde transport from the retina to the superior colliculus, as well as an increase in astrocyte reactivity, ultraestructural myelin alterations, and altered morphology of oligodendrocyte lineage in the optic nerve distal portion at early stages of experimental diabetes. Ischemia tolerance prevented a significant decrease of retinal glutamine synthetase activity induced by diabetes. These results suggest that early vision loss in diabetes could be abated by ischemic conditioning which preserved axonal function and structure.
Comba A, etal., J Biol Chem. 2016 Jan 22;291(4):1933-47. doi: 10.1074/jbc.M115.691972. Epub 2015 Nov 24.
Numerous reports have demonstrated a tumor inhibitory effect of polyunsaturated fatty acids (PUFAs). However, the molecular mechanisms modulating this phenomenon are in part poorly understood. Here, we provide evidence of a novel antitumoral mechanism of the PUFA arachidonic acid (AA). In vivo and i
n vitro experiments showed that AA treatment decreased tumor growth and metastasis and increased apoptosis. Molecular analysis of this effect showed significantly reduced expression of a subset of antiapoptotic proteins, including BCL2, BFL1/A1, and 4-1BB, in AA-treated cells. We demonstrated that down-regulation of the transcription factor glioma-associated protein 1 (GLI1) in AA-treated cells is the underlying mechanism controlling BCL2, BFL1/A1, and 4-1BB expression. Using luciferase reporters, chromatin immunoprecipitation, and expression studies, we found that GLI1 binds to the promoter of these antiapoptotic molecules and regulates their expression and promoter activity. We provide evidence that AA-induced apoptosis and down-regulation of antiapoptotic genes can be inhibited by overexpressing GLI1 in AA-sensitive cells. Conversely, inhibition of GLI1 mimics AA treatments, leading to decreased tumor growth, cell viability, and expression of antiapoptotic molecules. Further characterization showed that AA represses GLI1 expression by stimulating nuclear translocation of NFATc1, which then binds the GLI1 promoter and represses its transcription. AA was shown to increase reactive oxygen species. Treatment with antioxidants impaired the AA-induced apoptosis and down-regulation of GLI1 and NFATc1 activation, indicating that NFATc1 activation and GLI1 repression require the generation of reactive oxygen species. Collectively, these results define a novel mechanism underlying AA antitumoral functions that may serve as a foundation for future PUFA-based therapeutic approaches.
de Paola I, etal., PLoS One. 2015 Apr 7;10(4):e0121149. doi: 10.1371/journal.pone.0121149. eCollection 2015.
Cullin3 (Cul3), a key factor of protein ubiquitination, is able to interact with dozens of different proteins containing a BTB (Bric-a-brac, Tramtrack and Broad Complex) domain. We here targeted the Cul3-BTB interface by using the intriguing approach of stabilizing the alpha-helical conformation o
f Cul3-based peptides through the "stapling" with a hydrocarbon cross-linker. In particular, by combining theoretical and experimental techniques, we designed and characterized stapled Cul3-based peptides embedding the helix 2 of the protein (residues 49-68). Intriguingly, CD and NMR experiments demonstrate that these stapled peptides were able to adopt the helical structure that the fragment assumes in the parent protein. We also show that some of these peptides were able to bind to the BTB of the tetrameric KCTD11, a substrate adaptor involved in HDAC1 degradation, with high affinity (~ 300-600 nM). Cul3-derived staple peptides are also able to bind the BTB of the pentameric KCTD5. Interestingly, the affinity of these peptides is of the same order of magnitude of that reported for the interaction of full-length Cul3 with some BTB containing proteins. Moreover, present data indicate that stapling endows these peptides with an increased serum stability. Altogether, these findings indicate that the designed stapled peptides can efficiently mimic protein-protein interactions and are potentially able to modulate fundamental biological processes involving Cul3.
The abnormal activation of the epidermal growth factor (EGF) pathway is one of the most common findings in human cancer, and a number of molecular devices of laboratory and clinical relevance have been designed to block this transduction pathway. Because of the large number of cellular events that m
ight be regulated through the activation of the four EGF receptor family members, it is possible that screening methodologies for the identification of new molecular targets working downstream of these pathways may provide new tools for cancer diagnosis and potentially prevention and therapy. In searching for EGF target genes, we have identified ERG1.2, the mouse homolog of the solid tumor-associated gene STAG1. Both in humans and in mice, it belongs to a new gene family that can give origin to several protein isoforms through alternative splicing and/or multiple translation starts. Sequence analysis and experimental data suggest that ERG1.2 is likely to function as a membrane-bound protein interacting with downstream signaling molecules through WW- and SH3-binding domains. ERG1.2 is a cell-cycle-regulated gene, and both ERG1.2 and STAG1 are induced by EGF and other growth factors at the transcript and protein levels. Finally, we have demonstrated that, besides prostate cancer and renal cell carcinoma, STAG1 was also overexpressed in breast and ovarian cancer cell lines and in breast primary tumors. Although in most cases STAG1 overexpression is probably due to the abnormal activation of the EGF pathway, we have also demonstrated genetic amplification and rearrangement of its locus in one breast cancer cell line and one primary ovarian cancer, suggesting that STAG1 might be a direct molecular target in the carcinogenetic process. Thus its overexpression might be regarded not only as a tumor marker but also as a potentially pathogenetic event.
De Mori R, etal., Am J Hum Genet. 2017 Oct 5;101(4):552-563. doi: 10.1016/j.ajhg.2017.08.017. Epub 2017 Sep 28.
The Sonic Hedgehog (SHH) pathway is a key signaling pathway orchestrating embryonic development, mainly of the CNS and limbs. In vertebrates, SHH signaling is mediated by the primary cilium, and genetic defects affecting either SHH pathway members or ciliary proteins cause a spectrum of developmenta
l disorders. SUFU is the main negative regulator of the SHH pathway and is essential during development. Indeed, Sufu knock-out is lethal in mice, and recessive pathogenic variants of this gene have never been reported in humans. Through whole-exome sequencing in subjects with Joubert syndrome, we identified four children from two unrelated families carrying homozygous missense variants in SUFU. The children presented congenital ataxia and cerebellar vermis hypoplasia with elongated superior cerebellar peduncles (mild "molar tooth sign"), typical cranio-facial dysmorphisms (hypertelorism, depressed nasal bridge, frontal bossing), and postaxial polydactyly. Two siblings also showed polymicrogyria. Molecular dynamics simulation predicted random movements of the mutated residues, with loss of the native enveloping movement of the binding site around its ligand GLI3. Functional studies on cellular models and fibroblasts showed that both variants significantly reduced SUFU stability and its capacity to bind GLI3 and promote its cleavage into the repressor form GLI3R. In turn, this impaired SUFU-mediated repression of the SHH pathway, as shown by altered expression levels of several target genes. We demonstrate that germline hypomorphic variants of SUFU cause deregulation of SHH signaling, resulting in recessive developmental defects of the CNS and limbs which share features with both SHH-related disorders and ciliopathies.
Rodier G, etal., EMBO J 2001 Dec 3;20(23):6672-82.
The activity of the cyclin-dependent kinase inhibitor p27 is controlled by its concentration and subcellular localization. However, the mechanisms that regulate its intracellular transport are poorly understood. Here we show that p27 is phosphorylated on Ser10 in vivo and that mutation of Ser10 to A
la inhibits p27 cytoplasmic relocalization in response to mitogenic stimulation. In contrast, a fraction of wild-type p27 and a p27(S10D)-phospho-mimetic mutant translocates to the cytoplasm in the presence of mitogens. G1 nuclear export of p27 and its Ser10 phosphorylation precede cyclin-dependent kinase 2 (Cdk2) activation and degradation of the bulk of p27. Interestingly, leptomycin B-mediated nuclear accumulation accelerates the turnover of endogenous p27; the p27(S10A) mutant, which is trapped in the nucleus, has a shorter half-life than wild-type p27 and the p27(S10D) mutant. In summary, p27 is efficiently degraded in the nucleus and phosphorylation of Ser10 is necessary for the nuclear to cytoplasmic redistribution of a fraction of p27 in response to mitogenic stimulation. This cytoplasmic localization may serve to decrease the abundance of p27 in the nucleus below a certain threshold required for activation of cyclin-Cdk2 complexes.
Raducu M, etal., EMBO J. 2016 Jul 1;35(13):1400-16. doi: 10.15252/embj.201593374. Epub 2016 May 27.
Skp1-Cul1-F-box protein (SCF) ubiquitin ligases direct cell survival decisions by controlling protein ubiquitylation and degradation. Sufu (Suppressor of fused) is a central regulator of Hh (Hedgehog) signaling and acts as a tumor suppressor by maintaining the Gli (Glioma-associated oncogene homolo
g) transcription factors inactive. Although Sufu has a pivotal role in Hh signaling, the players involved in controlling Sufu levels and their role in tumor growth are unknown. Here, we show that Fbxl17 (F-box and leucine-rich repeat protein 17) targets Sufu for proteolysis in the nucleus. The ubiquitylation of Sufu, mediated by Fbxl17, allows the release of Gli1 from Sufu for proper Hh signal transduction. Depletion of Fbxl17 leads to defective Hh signaling associated with an impaired cancer cell proliferation and medulloblastoma tumor growth. Furthermore, we identify a mutation in Sufu, occurring in medulloblastoma of patients with Gorlin syndrome, which increases Sufu turnover through Fbxl17-mediated polyubiquitylation and leads to a sustained Hh signaling activation. In summary, our findings reveal Fbxl17 as a novel regulator of Hh pathway and highlight the perturbation of the Fbxl17-Sufu axis in the pathogenesis of medulloblastoma.
Petroni M, etal., Cell Death Differ. 2016 Feb;23(2):197-206. doi: 10.1038/cdd.2015.81. Epub 2015 Jun 12.
The MRE11/RAD50/NBS1 (MRN) complex is a major sensor of DNA double strand breaks, whose role in controlling faithful DNA replication and preventing replication stress is also emerging. Inactivation of the MRN complex invariably leads to developmental and/or degenerative neuronal defects, the pathoge
nesis of which still remains poorly understood. In particular, NBS1 gene mutations are associated with microcephaly and strongly impaired cerebellar development, both in humans and in the mouse model. These phenotypes strikingly overlap those induced by inactivation of MYCN, an essential promoter of the expansion of neuronal stem and progenitor cells, suggesting that MYCN and the MRN complex might be connected on a unique pathway essential for the safe expansion of neuronal cells. Here, we show that MYCN transcriptionally controls the expression of each component of the MRN complex. By genetic and pharmacological inhibition of the MRN complex in a MYCN overexpression model and in the more physiological context of the Hedgehog-dependent expansion of primary cerebellar granule progenitor cells, we also show that the MRN complex is required for MYCN-dependent proliferation. Indeed, its inhibition resulted in DNA damage, activation of a DNA damage response, and cell death in a MYCN- and replication-dependent manner. Our data indicate the MRN complex is essential to restrain MYCN-induced replication stress during neural cell proliferation and support the hypothesis that replication-born DNA damage is responsible for the neuronal defects associated with MRN dysfunctions.
Zhang X, etal., Biochem J. 2011 Jun 15;436(3):547-57. doi: 10.1042/BJ20110249.
ABC (ATP-binding cassette) subfamily D transporters are found in all eukaryotic kingdoms and are known to play essential roles in mammals and plants; however, their number, organization and physiological contexts differ. Via cross-kingdom expression experiments, we have explored the conservation of
targeting, protein stability and function between mammalian and plant ABCD transporters. When expressed in tobacco epidermal cells, the mammalian ABCD proteins ALDP (adrenoleukodystrophy protein), ALDR (adrenoleukodystrophy-related protein) and PMP70 (70 kDa peroxisomal membrane protein) targeted faithfully to peroxisomes and P70R (PMP70-related protein) targeted to the ER (endoplasmic reticulum), as in the native host. The Arabidopsis thaliana peroxin AtPex19_1 interacted with human peroxisomal ABC transporters both in vivo and in vitro, providing an explanation for the fidelity of targeting. The fate of X-linked adrenoleukodystrophy disease-related mutants differed between fibroblasts and plant cells. In fibroblasts, levels of ALDP in some 'protein-absent' mutants were increased by low-temperature culture, in some cases restoring function. In contrast, all mutant ALDP proteins examined were stable and correctly targeted in plant cells, regardless of their fate in fibroblasts. ALDR complemented the seed germination defect of the Arabidopsis cts-1 mutant which lacks the peroxisomal ABCD transporter CTS (Comatose), but neither ALDR nor ALDP was able to rescue the defect in fatty acid beta-oxidation in establishing seedlings. Taken together, our results indicate that the mechanism for trafficking of peroxisomal membrane proteins is shared between plants and mammals, but suggest differences in the sensing and turnover of mutant ABC transporter proteins and differences in substrate specificity and/or function.