Elevated levels of interleukin (IL)-18 have been reported in a number of allergic diseases. We recently reported that IL-18 in the blood and IL-18Ralpha mRNA in the oesophagus are induced during human eosinophilic oesophagitis (EoE). Additionally, we earlier showed that invariant natural killer T (i
NKT) cells are critical to EoE pathogenesis; however, the mechanism of iNKT cell activation in EoE is not well understood. Therefore, the current study focused on the hypothesis that allergen-induced IL-18 may have an important role in iNKT cell-mediated EoE pathogenesis. We first validated the human EoE findings of IL-18 in experimental EoE by examining blood levels of IL-18 and oesophageal IL-18Ralpha mRNA levels in aeroallergen- and food allergen-induced experimental mouse models of EoE. We demonstrate that blood IL-18 protein and oesophageal IL-18Ralpha mRNA are induced in the mouse model of EoE and that IL-18Ralpha is expressed by iNKT cells in the oesophagus. Intranasal delivery of rIL-18 induced both mast cells and eosinophilic inflammation in the oesophagus in a time- and dose-dependent manner. To establish the significance of IL-18 in EoE pathogenesis, we examined DOX-inducible rtTA-CC10-IL-18 bitransgenic mice that induce IL-18 protein expression in the oesophagus. Our analysis indicated that induction of IL-18 in these mice resulted in the development of many of the characteristics of EoE, including oesophageal intraepithelial eosinophilia, increased mast cells, oesophageal remodelling and fibrosis. The current study provides evidence that IL-18 may induce iNKT cell activation to release the eosinophil-activating cytokine IL-5, as IL-5-deficient mice and iNKT cell-deficient (CD1d null) mice do not induce EoE in response to intranasal IL-18 challenge. Taken together, these findings provide evidence that allergen-induced IL-18 has a significant role in promoting IL-5- and iNKT-dependent EoE pathogenesis.
Dutt A, etal., Proc Natl Acad Sci U S A. 2008 Jun 24;105(25):8713-7. Epub 2008 Jun 13.
Oncogenic activation of tyrosine kinases is a common mechanism of carcinogenesis and, given the druggable nature of these enzymes, an attractive target for anticancer therapy. Here, we show that somatic mutations of the fibroblast growth factor receptor 2 (FGFR2) tyrosine kinase gene, FGFR2, are pre
sent in 12% of endometrial carcinomas, with additional instances found in lung squamous cell carcinoma and cervical carcinoma. These FGFR2 mutations, many of which are identical to mutations associated with congenital craniofacial developmental disorders, are constitutively activated and oncogenic when ectopically expressed in NIH 3T3 cells. Inhibition of FGFR2 kinase activity in endometrial carcinoma cell lines bearing such FGFR2 mutations inhibits transformation and survival, implicating FGFR2 as a novel therapeutic target in endometrial carcinoma.
Vascular hyperplasia may be involved in the remodeling of vasculature. It was unknown if there were genetic determinants for aortic smooth muscle cell number (SMCN) and, if yes, whether they acted independently of those for blood pressure (BP). To unravel this issue, we utilized congenic strains pre
viously constructed for BP studies. These strains were made by replacing various Chromosome 2 segments of the Dahl salt-sensitive (S) rat with those of the Milan normotensive rat (MNS). We measured and compared SMCN in aortic cross sectional areas and BPs of these strains. Consequently, a quantitative trait locus (QTL) for SMCN was localized to a chromosome region not containing a BP QTL, but harboring the locus for the angiotensin II receptor AT1B (Agtr1b). Agtr1b became a candidate for the SMCN QTL because a) two significant mutations were found in the coding region between S and all congenic strains possessing the MNS alleles and b) contractile responses to angiotensin II were significantly and selectively reduced in congenic rats harboring the MNS alleles of the SMCN QTL as compared to S rats. The current investigation presents the first line of evidence that a QTL for aortic SMCN exists, and it acts independently of QTLs for BP. The relevant congenic strains developed therein potentially provide novel mammalian models for the studies of vascular remodeling disorders.
Dutta AK Med Hypotheses. 2015 Dec;85(6):736-9. doi: 10.1016/j.mehy.2015.10.019. Epub 2015 Oct 24.
Alcoholic liver disease is a major source of morbidity and mortality worldwide. Twin studies had demonstrated heritability of alcoholic liver disease. Although to date only Adiponutrin (PNPLA3) rs738409 polymorphism (I148M) had been unequivocally proved to be associated with increased risk of alcoho
lic liver disease across different ethnicities. This protein was previously thought to have a predominant lipolytic role. However, recent investigations have provided evidence of lipogenic activity of this protein. The current hypothesis paper is summarizing the recent evidences gleaned in biological role of Adiponutrin and bioinformatic pointers towards a role in lipid trafficking. A critical appraisal of the utility of murine models and cell based systems in investigating Adiponutrin is also presented. As the HepG2 cell line harbors the I148M mutation in homozygous state it is hypothesized that this should represent an ideal model system for PNPLA3 biology. Thus, as Adiponutrin is proposed as having both lipolytic and lipogenic/lipid trafficking roles it is termed as a Yin-Yang protein in analogy to ancient Chinese wisdom.
Angiogenin (ANG), a 14-kDa pro-angiogenic secreted protein, has been shown to play a role in cell migration and tumor invasion, which involve proteolytic cleavage of plasminogen to generate plasmin. However, the mechanism by which ANG regulates plasmin formation and cell migration was not known. Ou
r studies here detected elevated levels of secreted and cell surface-bound ANG in highly invasive metastatic breast cancer cells. ANG was also detected at very high levels in the tumor cells in infiltrating ductal carcinomas. By immunofluorescence and immunoprecipitation analysis, ANG was detected at the leading edges of the cell surfaces where it colocalized and interacted with members of the plasminogen activation system (PAS) such as annexin A2 (A2), calpactin (S100-A10) and urokinase plasminogen activator receptor (uPAR). Analysis of lipid raft (LR) and non-lipid raft (NLR) regions of the cell membranes showed the predominance of ANG, A2 and S100-A10 in the LR regions. In contrast, uPAR was detected predominantly in the NLR fractions, suggesting that ANG interacts with uPAR at the junctions of LR and NLR regions. ANG knockdown in T47D and MDA-MB-231 breast cancer cell lines did not affect the cellular expression of A2, S100-A10 and uPAR but decreased cell migration and plasmin formation. Neutralization of ANG with monoclonal antibodies similarly decreased the migration of MDA-MB-231 cells. In the presence of ANG, uPAR was observed to interact with uPA, which is necessary for plasmin formation. Conversely, in the absence of ANG, uPAR did not interact with uPA and FAK and Src kinases were observed to be dephosphorylated. Exogenous addition of recombinant ANG to ANG knocked down MDA-MB-231 cells restored FAK phosphorylation, uPAR interactions with uPA, plasmin formation as well as migration of these cells. Taken together, our results identified a novel role for ANG as a member of the uPAR interactome that facilitates the interaction of uPAR with uPA, leading to plasmin formation and cell migration necessary for tumor invasion and metastasis of breast cancer cells.
Dutra MS, etal., J Infect Dis. 2013 Jan 1;207(1):152-63. doi: 10.1093/infdis/jis640. Epub 2012 Oct 24.
Retinochoroiditis manifests in patients infected with Toxoplasma gondii. Here, we assessed 30 sibships and 89 parent/case trios of presumed ocular toxoplasmosis (POT) to evaluate associations with polymorphisms in the NOD2 gene. Three haplotype-tagging single-nucleotide polymorphisms (tag-SNPs) with
in the NOD2 gene were genotyped. The family-based association test showed that the tag-SNP rs3135499 is associated with retinochoroiditis (P = .039). We then characterized the cellular immune response of 59 cases of POT and 4 cases of active ocular toxoplasmosis (AOT). We found no differences in levels of interferon gamma (IFN-gamma) and interleukin 2 produced by T-helper 1 cells when comparing patients with AOT or POT to asymptomatic individuals. Unexpectedly, we found an increased interleukin 17A (IL-17A) production in patients with POT or OAT. In patients with POT or AOT, the main cellular source of IL-17A was CD4(+)CD45RO(+)T-bet(-)IFN-gamma(-) T-helper 17 cells. Altogether, our results suggest that NOD2 influences the production of IL-17A by CD4(+) T lymphocytes and might contribute to the development of ocular toxoplasmosis.
The innate immune system pattern recognition receptors (PRR) are the first line of host defenses recognizing the various pathogen- or danger-associated molecular patterns and eliciting defenses by regulating the production of pro-inflammatory cytokines such as IL-1beta, IL-18 or interferon beta (IF
N-beta). NOD-like receptors (NLRs) and AIM2-like receptors (ALRs) are cytoplasmic inflammasome sensors of foreign molecules, including DNA. IFI16, a sequence-independent nuclear innate sensor ALR, recognizes episomal dsDNA genomes of herpes viruses such as KSHV, EBV, and HSV-1 in the infected cell nuclei, forms an inflammasome complex with ASC and procaspase1, and relocates into the cytoplasm leading into Caspase-1 and IL-1beta generation. IFI16 also induces IFN-beta during HSV-1 infection via the cytoplasmic STING-TBK1-IRF3 pathway. Thus far, whether IFI16 recognizes foreign DNA directly or utilizes other host protein(s) is unknown. Here, we demonstrate that BRCA1, a DNA damage repair sensor and transcription regulator, is in complex with IFI16 in the host cell nucleus, and their association increases in the presence of nuclear viral genomes during de novo KSHV, EBV and HSV-1 infection, and in latent KSHV or EBV infection, but not by DNA damage responses (DDR) induced by bleomycin and vaccinia virus cytoplasmic dsDNA. BRCA1 is a constituent of the triggered IFI16-inflammasome and is translocated into the cytoplasm after genome recognition along with the IFI16-inflammasome. The absence of BRCA1 abrogated IFI16-viral genome association, inflammasome assembly, IFI16 cytoplasmic localization, and Caspase-1 and IL-1beta production. The absence of BRCA1 also abolished the cytoplasmic IFI16-STING interaction, downstream IRF3 phosphorylation, nuclear translocation of pIRF3 and IFN-beta production during de novo KSHV and HSV-1 infection. These findings highlight that BRCA1 plays a hitherto unidentified innate immunomodulatory role by facilitating nuclear foreign DNA sensing by IFI16, subsequent assembly and cytoplasmic distribution of IFI16-inflammasomes leading into IL-1beta formation and the induction of IFN-beta via cytoplasmic signaling through IFI16-STING, TBK1 and IRF3.
Oxytocin and its receptor are potentially important for cardiovascular functions. In the present paper, we report their chromosome locations in the rat and their comparative mapping with the mouse and human. They are located in chromosome regions previously known to contain quantitative trait loci f
Dutta A, etal., Structure. 2012 Nov 7;20(11):1838-49. doi: 10.1016/j.str.2012.08.012. Epub 2012 Sep 6.
Ionotropic glutamate receptors (iGluRs) harbor two extracellular domains: the membrane-proximal ligand-binding domain (LBD) and the distal N-terminal domain (NTD). These are involved in signal sensing: the LBD binds L-glutamate, which activates the receptor channel. Ligand binding to the NTD modulat
es channel function in the NMDA receptor subfamily of iGluRs, which has not been observed for the AMPAR subfamily to date. Structural data suggest that AMPAR NTDs are packed into tight dimers and have lost their signaling potential. Here, we assess NTD dynamics from both subfamilies, using a variety of computational tools. We describe the conformational motions that underly NMDAR NTD allosteric signaling. Unexpectedly, AMPAR NTDs are capable of undergoing similar dynamics; although dimerization imposes restrictions, the two subfamilies sample similar, interconvertible conformational subspaces. Finally, we solve the crystal structure of AMPAR GluA4 NTD, and combined with molecular dynamics simulations, we characterize regions pivotal for an as-yet-unexplored dynamic spectrum of AMPAR NTDs.
Myostatin (MSTN) has been implicated in metabolic adaptation to physiological stimuli, such as physical exercise, which is linked to improved glucose homeostasis. The aim of the present study was to evaluate the influence of exercise on the expression of MSTN, MSTN receptors (ActRIIB and ALK4) and f
ollistatin (FS) in the muscle and fat of streptozotocin-induced diabetic rats. Control and diabetic rats were randomly assigned to a swimming training group (EC and ED, respectively) and a sedentary group (SC and SD, respectively). Exercising animals swam for 45 min at 0900 and 1700 hours, 5 day/week, for 4 weeks. The mRNA expression of MSTN, ActRIIB, ALK4 and FS mRNA was quantified by real-time reverse transcription-polymerase chain reaction. Expression of MSTN and FS mRNA increased in the muscle and subcutaneous fat of SD compared with SC rats. Expression of ActRIIB mRNA was increased in the muscle, mesenteric fat and brown adipose tissue (BAT) of SD compared with SC rats, whereas ALK4 mRNA expression was only increased in the BAT of SD compared with SC rats. After training, MSTN and ActRIIB expression was lower in the BAT of EC compared with SC rats. Expression of MSTN mRNA increased in the mesenteric fat of ED compared with SD rats, whereas FS mRNA expression decreased in the muscle, mesenteric and subcutaneous fat and BAT. Lower ALK4 mRNA expression was noted in the BAT of ED compared with SD rats. These results indicate that MSTN, its receptors and FS expression change in both the muscle and fat of diabetic rats and that the expression of these factors can be modulated by exercise in diabetes.
Dutil J and Deng AY, Physiol Genomics 2001 Jun 6;6(1):3-9.
Both linkage and use of congenic strains have shown that a region on rat chromosome 2 (Chr 2) of Dahl salt-sensitive rats (S) contained a quantitative trait locus (QTL) for blood pressure (BP). A congenic strain was made by replacing a segment of the S rat by the homologous region of the Milan normo
tensive (MNS) rat. Since the region was roughly 80 cM in size, a further reduction is required toward the final identification of the QTL. Currently, three congenic substrains were made by replacing smaller sections within the 80 cM. Each strain contains a specific region of MNS in the S genetic background. Two of the three congenic strains shared a segment in common, and both showed a BP-lowering effect. One of the three congenic strains carried a unique segment and had the same BP as S. Deducing the fragment shared in the two substrains having an effect, the BP QTL has to be present in a region of roughly 15 cM. In contrast to BP, heart rates of all the congenic rats were the same as that of the S rat. Thus BP and the heart rate are under the control of independent genetic determinants.
Dutta A, etal., Science. 2016 Jun 24;352(6293):1576-80. doi: 10.1126/science.aad9512.
The NKX3.1 homeobox gene plays essential roles in prostate differentiation and prostate cancer. We show that loss of function of Nkx3.1 in mouse prostate results in down-regulation of genes that are essential for prostate differentiation, as well as up-regulation of genes that are not normally expre
ssed in prostate. Conversely, gain of function of Nkx3.1 in an otherwise fully differentiated nonprostatic mouse epithelium (seminal vesicle) is sufficient for respecification to prostate in renal grafts in vivo. In human prostate cells, these activities require the interaction of NKX3.1 with the G9a histone methyltransferase via the homeodomain and are mediated by activation of target genes such as UTY (KDM6c), the male-specific paralog of UTX (KDM6a) We propose that an NKX3.1-G9a-UTY transcriptional regulatory network is essential for prostate differentiation, and we speculate that disruption of such a network predisposes to prostate cancer.
Dutil J, etal., Cancer Genet. 2012 May;205(5):242-8. doi: 10.1016/j.cancergen.2012.04.002.
Mutations in the breast cancer 1, early onset (BRCA1) and breast cancer 2 (BRCA2) genes are responsible for the majority of hereditary breast cancers. Knowledge of the incidence and prevalence of BRCA mutations in a specific population or ethnic group is necessary to provide accurate genetic counsel
ing for breast cancer patients and their families; however, these data have not been gathered in the population of Puerto Rico. We conducted a retrospective study of female breast cancer patients undergoing genetic testing for BRCA mutations in the highest-volume breast surgery practices in San Juan, Puerto Rico. Data collection includes three-generation family cancer history and results from complete BRCA sequencing. A total of six different deleterious mutations were observed, including one mutation in BRCA1 and five mutations in BRCA2. Three recurrent mutations (BRCA1 del exon1-2, BRCA2 4150G>T, and BRCA2 6027del4) account for over 70% of all the BRCA mutations observed in this study population. This study examines for the first time the characteristics of hereditary breast cancer in Puerto Rico and assesses the accuracy of existing genetic risk assessment tools in that population. This data is expected to contribute to providing accurate and efficient tools for the clinical management of hereditary breast cancer in Puerto Rico.
BACKGROUND AND PURPOSE: Phosphoinositide 3-kinase-gamma (PI3Kgamma) is implicated in many pathophysiological conditions, and recent evidence has suggested its involvement in colitis. In the present study, we investigated the effects of AS605240, a relatively selective PI3Kgamma inhibitor, in experim
ental colitis and its underlying mechanisms. EXPERIMENTAL APPROACH: Acute colitis was induced in mice by treatment with trinitrobenzene sulphonic acid (TNBS), and the effect of AS605240 on colonic injury was assessed. Pro-inflammatory mediators and cytokines were measured by immunohistochemistry, elisa, real time-polymerase chain reaction and flow cytometry. KEY RESULTS: Oral administration of AS605240 significantly attenuated TNBS-induced acute colitis and diminished the expression of matrix metalloproteinase-9 and vascular endothelial growth factor. The colonic levels and expression of IL-1beta, CXCL-1/KC, MIP-2 and TNF-alpha were also reduced following therapeutic treatment with AS605240. Moreover, AS605240 reduced MIP-2 levels in a culture of neutrophils stimulated with lipopolysaccharide. The mechanisms underlying these actions of AS605240 are related to nuclear factor-kappa (NF-kappaB) inhibition. Importantly, the PI3Kgamma inhibitor also up-regulated IL-10, CD25 and FoxP3 expression. In addition, a significant increase in CD25 and FoxP3 expression was found in isolated lamina propria CD4+ T cells of AS605240-treated mice. The effect of AS605240 on Treg induction was further confirmed by showing that concomitant in vivo blockade of IL-10R significantly attenuated its therapeutic activity. CONCLUSIONS AND IMPLICATIONS: These results suggest that AS605240 protects mice against TNBS-induced colitis by inhibiting multiple inflammatory components through the NF-kappaB pathway while simultaneously inducing an increase in the functional activity of CD4+CD25+ Treg. Thus, AS605240 may offer a promising new therapeutic strategy for the treatment of inflammatory bowel diseases.
Dutil J and Deng AY, Mamm Genome 2001 May;12(5):362-5.
A region on rat Chromosome (Chr) 2 of the Dahl salt-sensitive rat (S) was shown previously to contain a quantitative trait locus (QTL) for blood pressure (BP). This was achieved first by linkage, followed by the use of congenic strains. A congenic strain, designated S.MNS-D2Mit6/Adh, contained a seg
ment of Chr 2 from the Milan Normotensive (MNS) rat in the S genetic background. Since the region containing the QTL was roughly 80 cM in size, a further reduction was needed towards the positional or candidate gene cloning. Currently, two congenic substrains were made from the original strain S.MNS-D2Mit6/Adh. One of these two substrains showed a BP-lowering effect, whereas the other substrain did not. Deducing the segment not shared in the two substrains, the BP QTL has to be present in a chromosome region of roughly 5.7 cM between the marker D2Rat303 and the locus for the neutroendopeptidase gene (Nep). Nep is not included within the segment. This region does not seem to contain any candidate genes well known for the BP control. Thus, the final identification of the QTL will most likely lead to the discovery of a brand new gene for the BP regulation.
Dutta P, etal., BMC Cancer. 2016 Jan 21;16:33. doi: 10.1186/s12885-016-2053-3.
BACKGROUND: miRNAs can regulate cellular survival in various cancer cell types. Recent evidence implicates the formation of lipid droplets as a hallmark event during apoptotic cell death response. It is presently unknown whether MIR494, located at 14q32 which is deleted in renal cancers, reduces cel
l survival in renal cancer cells and if this process is accompanied by changes in the number of lipid droplets. METHODS: 769-P renal carcinoma cells were utilized for this study. Control or MIR494 mimic was expressed in these cells following which cell viability (via crystal violet) and apoptotic cell numbers (via Annexin V/PI staining) were assessed. By western blotting, MIR494 cellular responses were validated using MIR494 antagomir and Argonaute 2 siRNA. Transmission electron microscopy (TEM) was performed in MIR494-transfected 769-P cells to identify ultrastructural changes. LipidTOX green neutral lipid staining and cholesterol measurements were conducted to assess accumulation of lipids droplets and total cholesterol levels, respectively, in MIR494 expressing 769-P cells. Indirect immunofluorescence and western analyses were also performed to examine changes in mitochondria organization. Co-transfection of MIR494 mimic with siRNA targeting LC3B and ATG7 was conducted to assess their contribution to formation of lipid droplets in MIR494-expressing cells. RESULTS: MIR494 expression reduces viability of 769-P renal cancer cells; this was accompanied by increased cleaved PARP (an apoptotic marker) and LC3B protein. Further, expression of MIR494 increased LC3B mRNA levels and LC3B promoter activity (2.01-fold; 50% increase). Interestingly, expression of MIR494 markedly increased multilamellar bodies and lipid droplets (by TEM and validated by LipidTOX immunostaining) while reducing total cholesterol levels. Via immunocytochemistry, we observed increased LC3B-associated endogenous punctae upon MIR494 expression. In contrast to ATG7 siRNA, knockdown of LC3B reduced the numbers of lipid droplets in MIR494-expressing cells. Our results also identified that MIR494 expression altered the organization of mitochondria which was accompanied by co-localization with LC3B punctae, decreased PINK1 protein, and altered Drp1 intracellular distribution. CONCLUSION: Collectively, our findings indicate that MIR494 reduces cell survival in 769-P renal cancer cells which is accompanied by increased lipid droplet formation (which occurs in a LC3B-dependent manner) and mitochondrial changes.
Dutil J, etal., Hypertension 2005 Apr;45(4):557-64. Epub 2005 Feb 28.
Our previous work demonstrated 2 quantitative trait loci (QTLs), C2QTL1 and C2QTL2, for blood pressure (BP) located on chromosome (Chr) 2 of Dahl salt-sensitive (DSS) rats. However, for a lack of markers, the 2 congenic strains delineating C2QTL1 and C2QTL2 could not be separated. The position of th
e C2QTL1 was only inferred by comparing 2 congenic strains, one having and another lacking a BP effect. Furthermore, it was not known how adjacent QTLs would interact with one another on Chr 2. In the current investigation, first, a critical chromosome marker was developed to separate 2 C2QTLs. Second, a congenic substrain was created to cover a chromosome fragment thought to harbor C2QTL1. Finally, a series of congenic strains was produced to systematically and comprehensively cover the entire Chr 2 segment containing C2QTL2 and other regions previously untested. Consequently, a total of 3 QTLs were discovered, with C2QTL3 located between C2QTL1 and C2QTL2. C2QTL1, C2QTL2, and C2QTL3 reside in chromosome segments of 5.7 centiMorgan (cM), 3.5 cM, and 1.5 cM, respectively. C2QTL1 interacted epistatically with either C2QTL2 or C2QTL3, whereas C2QTL2 and C2QTL3 showed additive effects to each other. These results suggest that BP QTLs closely linked in a segment interact epistatically and additively to one another on Chr 2.
Dutta S, etal., Cancer Res. 2016 Jan 15;76(2):418-28. doi: 10.1158/0008-5472.CAN-15-1488. Epub 2015 Nov 11.
Neuropilin-2 (NRP2) is a non-tyrosine kinase receptor frequently overexpressed in various malignancies, where it has been implicated in promoting many protumorigenic behaviors, such as imparting therapeutic resistance to metastatic cancer cells. Here, we report a novel function of NRP2 as a regulat
or of endocytosis, which is enhanced in cancer cells and is often associated with increased metastatic potential and drug resistance. We found that NRP2 depletion in human prostate and pancreatic cancer cells resulted in the accumulation of EEA1/Rab5-positive early endosomes concomitant with a decrease in Rab7-positive late endosomes, suggesting a delay in early-to-late endosome maturation. NRP2 depletion also impaired the endocytic transport of cell surface EGFR, arresting functionally active EGFR in endocytic vesicles that consequently led to aberrant ERK activation and cell death. Mechanistic investigations revealed that WD-repeat- and FYVE-domain-containing protein 1 (WDFY1) functioned downstream of NRP2 to promote endosome maturation, thereby influencing the endosomal trafficking of EGFR and the formation of autolysosomes responsible for the degradation of internalized cargo. Overall, our results indicate that the NRP2/WDFY1 axis is required for maintaining endocytic activity in cancer cells, which supports their oncogenic activities and confers drug resistance. Therefore, therapeutically targeting endocytosis may represent an attractive strategy to selectively target cancer cells in multiple malignancies.
Dutto I, etal., PLoS One. 2016 Jan 5;11(1):e0146031. doi: 10.1371/journal.pone.0146031. eCollection 2016.
The cell cycle inhibitor p21CDKN1A was previously found to interact directly with DNA nick-sensor poly(ADP-ribose) polymerase-1 (PARP-1) and to promote base excision repair (BER). However, the molecular mechanism responsible for this BER-related association of p21 with PARP-1 remains to be clarified
. In this study we investigate the capability of p21 to influence PARP-1 binding to DNA repair intermediates in a reconstituted BER system in vitro. Using model photoreactive BER substrates containing single-strand breaks, we found that full-length recombinant GST-tagged p21 but not a C-terminal domain truncated form of p21 was able to stimulate the PARP-1 binding to BER intermediates with no significant influence on the catalytic activity of PARP-1. In addition, we investigate whether the activation of PARP-1 through poly(ADP-ribose) (PAR) synthesis, is required for its interaction with p21. We have found that in human fibroblasts and in HeLa cells treated with the DNA alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), the interaction of p21 with PARP-1 was greatly dependent on PAR synthesis. In fact, an anti-PAR antibody was able to co-immunoprecipitate p21 and PARP-1 from extracts of MNNG-treated cells, while blocking PAR synthesis with the PARP-1 inhibitor Olaparib, drastically reduced the amount of p21 co-immunoprecipitated by a PARP-1 antibody. Our results provide the first evidence that p21 can stimulate the binding of PARP-1 to DNA repair intermediates, and that this cooperation requires PAR synthesis.
Dutta S, etal., Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):1065-70. Epub 2001 Jan 16.
The homeobox factor PDX-1 is a key regulator of pancreatic morphogenesis and glucose homeostasis; targeted disruption of the PDX-1 gene leads to pancreatic agenesis in pdx-1(-/-) homozygotes. Pdx-1 heterozygotes develop normally, but they display glucose intolerance in adulthood. Like certain other
homeobox proteins, PDX-1 contains a consensus FPWMK motif that promotes heterodimer formation with the ubiquitous homeodomain protein PBX. To evaluate the importance of PDX-1:PBX complexes in pancreatic morphogenesis and glucose homeostasis, we expressed either wild-type or PBX interaction defective PDX-1 transgenes under control of the PDX-1 promoter. Both wild-type and mutant PDX-1 transgenes corrected glucose intolerance in pdx-1 heterozygotes. The wild-type PDX-1 transgene rescued the development of all pancreatic lineages in pdx-1(-/-) animals, and these mice survived to adulthood. In contrast, pancreata from pdx-1(-/-) mice expressing the mutant PDX-1 transgene were hypoplastic, and these mice died within 3 weeks of birth from pancreatic insufficiency. All pancreatic cell types were observed in pdx-1(-/-) mice expressing the mutant PDX-1 transgene; but the islets were smaller, and increased numbers of islet hormone-positive cells were noted within the ductal epithelium. These results indicate that PDX-1:PBX complexes are dispensable for glucose homeostasis and for differentiation of stem cells into ductal, endocrine, and acinar lineages; but they are essential for expansion of these populations during development.
The aim of this study was to understand the association of human papillomavirus (HPV) type 16/18 infection and polymorphisms in the HLA-DQB1 (rs6457617) and IL-1β -511 (rs16944) loci with the development of uterine cervical cancer (CaCx). The distribution of HLA-DQB1 G > A and IL-1β -511 C/T polymor
phisms was determined in HPV-negative cervical swabs from normal women (N = 111) and compared with cervical swabs of HPV-cleared normal women (once HPV infected followed by natural clearance of the infection, N = 86), HPV16/18-positive cervical intraepithelial neoplasia (CIN, N = 41) and CaCx biopsies (N = 107). The A-allele containing genotypes (i.e. G/A and A/A) of HLA-DQB1 was significantly associated with CaCx compared with HPV-negative [OR = 2.56(1.42-4.62), p = 0.001] or HPV-cleared [OR = 2.07(1.12-3.87), p = 0.01] normal women, whereas the T-allele containing genotypes (i.e. C/T and T/T) of IL-1β showed increased risk of CIN [OR = 3.68(0.97-16.35), p = 0.03; OR = 3.59(0.92-16.38), p = 0.03] and CaCx development [OR = 2.03(1.03-5.2), p = 0.02; OR = 2.25(0.96-5.31), p = 0.04] compared with HPV-negative or HPV-cleared normal women. Considering these two loci together, it was evident that the T- and A-alleles rendered significantly increased susceptibility for development of CIN and CaCx compared with HPV-negative and HPV-cleared normal women. Moreover, the T-allele of IL-1β showed increased susceptibility for CIN [OR = 3.62(0.85-17.95), p = 0.04] and CaCx [OR = 2.39(0.91-6.37), p = 0.05] development compared with the HPV-cleared women, even in the presence of the HLA-DQB1 G-allele. Thus, our data suggest that persistent HPV16/18 infection in the cervix due to the presence of the HLA-DQB1 A-allele and chronic inflammation due to the presence of the IL-1β -511 T-allele might predispose women to CaCx development.
BACKGROUND/AIMS: Furosemide is a loop diuretic widely used in clinical practice for the treatment of oedema and hypertension. The aim of this study was to determine physiological and molecular changes in the hypothalamic-neurohypophysial system as a consequence of furosemide-induced sodiu
m depletion. METHODS: Male rats were sodium depleted by acute furosemide injection (10 and 30 mg/kg) followed by access to low sodium diet and distilled water for 24 h. The renal and behavioural consequences were evaluated, while blood and brains were collected to evaluate the neuroendocrine and gene expression responses. RESULTS: Furosemide treatment acutely increases urinary sodium and water excretion. After 24 h, water and food intake were reduced, while plasma angiotensin II and corticosterone were increased. After hypertonic saline presentation, sodium-depleted rats showed higher preference for salt. Interrogation using RNA sequencing revealed the expression of 94 genes significantly altered in the hypothalamic paraventricular nucleus (PVN) of sodium-depleted rats (31 upregulated and 63 downregulated). Out of 9 genes chosen, 5 were validated by quantitative PCR in the PVN (upregulated: Ephx2, Ndnf and Vwf; downregulated: Caprin2 and Opn3). The same genes were also assessed in the supraoptic nucleus (SON, upregulated: Tnnt1, Mis18a, Nr1d1 and Dbp; downregulated: Caprin2 and Opn3). As a result of these plastic transcriptome changes, vasopressin expression was decreased in PVN and SON, whilst vasopressin and oxytocin levels were reduced in plasma. CONCLUSIONS: We thus have identified novel genes that might regulate vasopressin gene expression in the hypothalamus controlling the magnocellular neurons secretory response to body sodium depletion and consequently hypotonic stress.
Dutta AK, etal., Am J Physiol Gastrointest Liver Physiol. 2016 Jan 1;310(1):G34-42. doi: 10.1152/ajpgi.00146.2015. Epub 2015 Nov 5.
TMEM16A is a newly identified Ca(2+)-activated Cl(-) channel in biliary epithelial cells (BECs) that is important in biliary secretion. While extracellular ATP stimulates TMEM16A via binding P2 receptors and increasing intracellular Ca(2+) concentration ([Ca(2+)]i), the regulatory pathways have not
been elucidated. Protein kinase C (PKC) contributes to ATP-mediated secretion in BECs, although its potential role in TMEM16A regulation is unknown. To determine whether PKCalpha regulates the TMEM16A-dependent membrane Cl(-) transport in BECs, studies were performed in human biliary Mz-cha-1 cells. Addition of extracellular ATP induced a rapid translocation of PKCalpha from the cytosol to the plasma membrane and activation of whole cell Ca(2+)-activated Cl(-) currents. Currents demonstrated outward rectification and reversal at 0 mV (properties consistent with TMEM16A) and were inhibited by either molecular (siRNA) or pharmacologic (PMA or Go6976) inhibition of PKCalpha. Intracellular dialysis with recombinant PKCalpha activated Cl(-) currents with biophysical properties identical to TMEM16A in control cells but not in cells after transfection with TMEM16A siRNA. In conclusion, our studies demonstrate that PKCalpha is coupled to ATP-stimulated TMEM16A activation in BECs. Targeting this ATP-Ca(2+)-PKCalpha signaling pathway may represent a therapeutic strategy to increase biliary secretion and promote bile formation.
Dutta D and Donaldson JG, Traffic. 2015 Sep;16(9):994-1009. doi: 10.1111/tra.12302. Epub 2015 Jun 4.
Clathrin-mediated endocytosis (CME) and clathrin-independent endocytosis (CIE) co-exist in most cells but little is known about their communication and coordination. Here we show that when CME was inhibited, endocytosis by CIE continued but endosomal trafficking of CIE cargo proteins was altered. CI
E cargo proteins that normally traffic directly into Arf6-associated tubules after internalization and avoid degradation (CD44, CD98 and CD147) now trafficked to lysosomes and were degraded. The endosomal tubules were also absent and Arf6-GTP levels were elevated. The altered trafficking, loss of the tubular endosomal network and elevated Arf6-GTP levels caused by inhibition of CME were rescued by expression of Rab35, a Rab associated with clathrin-coated vesicles, or its effector ACAPs, Arf6 GTPase activating proteins (GAP) that inactivate Arf6. Furthermore, siRNA knockdown of Rab35 recreated the phenotype of CME ablation on CIE cargo trafficking without altering endocytosis of transferrin. These observations suggest that Rab35 serves as a CME detector and that loss of CME, or Rab35 input, leads to elevated Arf6-GTP and shifts the sorting of CIE cargo proteins to lysosomes and degradation.
The parkin-associated endothelial-like receptor (PAELR, GPR37) is an orphan G protein-coupled receptor that interacts with and is degraded by parkin-mediated ubiquitination. Mutations in parkin are thought to result in PAELR accumulation and increase neuronal cell death in Parkinson's disease. In th
is study, we find that the protein interacting with C-kinase (PICK1) interacts with PAELR. Specifically, the Postsynaptic density protein-95/Discs large/ZO-1 (PDZ) domain of PICK1 interacted with the last three residues of the c-terminal (ct) located PDZ motif of PAELR. Pull-down assays indicated that recombinant and native PICK1, obtained from heterologous cells and rat brain tissue, respectively, were retained by a glutathione S-transferase fusion of ct-PAELR. Furthermore, coimmunoprecipitation studies isolated a PAELR-PICK1 complex from transiently transfected cells. PICK1 interacts with parkin and our data showed that PICK1 reduces PAELR expression levels in transiently transfected heterologous cells compared to a PICK1 mutant that does not interact with PAELR. Finally, PICK1 over-expression in HEK293 cells reduced cell death induced by PAEALR over-expression during rotenone treatment and these effects of PICK1 were attenuated during inhibition of the proteasome. These results suggest a role for PICK1 in preventing PAELR-induced cell toxicity.
Thioredoxin is a major component of thiol-reducing system. Recently, we identified thioredoxin-binding protein-2 (TBP-2) as a negative regulator of thioredoxin. Here, we report the role of TBP-2 in oxidative renal tubular injury and the subsequent carcinogenesis by ferric nitrilotriacetate. TBP-2 wa
s abundantly expressed in the rat kidney. Immunohistochemical analysis revealed that TBP-2 was present in association with nuclei and mitochondrial intermembrane space in the proximal tubular cells and coimmunoprecipitated with cytochrome c. After acute oxidative tubular damage, TBP-2 protein, but not messenger RNA, markedly decreased, demonstrating shortened half-life of this protein. Most cases of the induced renal cell carcinoma showed undetectable levels of TBP-2 protein, which was associated with the methylation of CpG island in the promoter region. Genome sequence analyses identified the poly-A tract in the 3' untranslated region as a mutation hot spot in this rather nonselective environment. Collectively, the amounts of TBP-2 protein were inversely associated with proliferation of tubular cells, as evaluated by proliferating cell nuclear antigen. These results suggest that loss of TBP-2 is essential for proliferation of not only neoplastic but also non-neoplastic renal tubular cells, and that TBP-2 is a target gene in oxidative stress-induced renal carcinogenesis by ferric nitrilotriacetate.
The murine gammaherpesvirus 68 (MHV-68) is an ideal model system for the study of interactions between gammaherpesviruses and their hosts. Intranasal infection of mice with MHV-68 results in replication of the virus in the lung epithelium followed by latent infection of B cells. Resolution of produc
tive MHV-68 infection depends on the adaptive immune system, but little is known about the role of innate immune mechanisms and the early interaction between the host and the virus. In this report, we have used mice that are deficient in components of the early defence system, the common type I interferon (IFN) receptor (IFN R), the transcriptional activator IRF-1, and the inducible nitric oxide synthase, to investigate the contribution of these mechanisms to control of MHV-68 infection. We show that while wild-type mice are highly resistant to infection with MHV-68, mice unresponsive to type I IFNs (IFN-alpha/beta R(-/-) ) are highly susceptible to the virus. At high multiplicities of infection (m.o.i. ; 4 x 10(6) PFU), 80-90% of IFN-alpha/beta R(-/-) mice succumb to infection, and at low m.o.i. (4 x 10(3) PFU), 50% mortality rates occur. Both high and low doses of virus lead to 100- to 1000-fold higher lung virus titres in IFN-alpha/beta R(-/-) mice than are found in wild-type mice and result in systemic dissemination of the virus. Latently infected cells are detectable in the spleens of IFN-alpha/beta R(-/-) mice earlier than in wild-type mice, and the numbers of latently infected cells are 10-fold higher in the IFN-alpha/beta R(-/-) mice during the acute phase of infection. We find IRF-1 has a critical role in protection from fatal disease, whereas inducible nitric oxide synthase does not appear to be important. The results indicate that innate immune mechanisms are critical for the early control of MHV-68 and may play a role in the establishment of latency.
Mechanisms of natural killer T (NKT)-cell activation remain unclear. Here, we report that during Trypanosoma cruzi infection, interleukin-12 (IL-12) deficiency or anti-CD1d antibody treatment prevents normal activation. The required IL-12 arises independently of MyD88. The data support a model of no
Duthie SJ, etal., Cancer Prev Res (Phila Pa). 2010 Jan;3(1):92-100.
Folate deficiency is implicated in human colon cancer. The effects of feeding rats a folate-deficient diet for 24 weeks on DNA damage (8-oxo-7,8-dihydroguanine), DNA repair [O(6)-methylguanine-DNA methyltransferase (MGMT) and 8-oxoguanine-DNA glycosylase (OGG-1) activity], and epigenetic parameters
(genome-wide cytosine methylation and indices of cellular methylation status) were investigated. Relative to control diet, the folate-deficient diet resulted in significantly reduced levels of serum ( approximately 80%; P < 0.0001), whole blood ( approximately 40%; P < 0.0001), and tissue folate (between 25% and 60% depending on the tissue sampled; P < 0.05); increased plasma total homocysteine ( approximately 35%; P < 0.05); and decreased S-adenosylmethionine to S-adenosylhomocysteine concentrations ( approximately 11%; P < 0.05). There was no significant change in the levels of 5-methyldeoxycytidine in liver or colon DNA, nor in the activity of liver DNA cytosine methyltransferase. However, there were significant increases in 8-oxo-7,8-dihydroguanine (P < 0.001) in lymphocyte DNA and in levels of the DNA repair proteins OGG-1 ( approximately 27%; P < 0.03) and MGMT ( approximately 25%; P < 0.003) in the liver, but not in the colon. This may reflect the ability of the liver, but not the colon, to upregulate DNA repair enzymes in response to either elevated DNA damage or an imbalance in the nucleotide precursor pool. These results show that folate deficiency can significantly modulate DNA damage and DNA repair, providing mechanisms by which it plays a role in the etiology of human cancer. We speculate that the inability of colon tissue to respond to folate deficiency occurs in humans and may increase the potential for malignant transformation.
Duttke SH, etal., Front Neurosci. 2022 May 16;16:858427. doi: 10.3389/fnins.2022.858427. eCollection 2022.
Substance abuse and addiction represent a significant public health problem that impacts multiple dimensions of society, including healthcare, the economy, and the workforce. In 2021, over 100,000 drug overdose deaths were reported in the US, with an alarming increase in fatalities related to opioid
s and psychostimulants. Understanding the fundamental gene regulatory mechanisms underlying addiction and related behaviors could facilitate more effective treatments. To explore how repeated drug exposure alters gene regulatory networks in the brain, we combined capped small (cs)RNA-seq, which accurately captures nascent-like initiating transcripts from total RNA, with Hi-C and single nuclei (sn)ATAC-seq. We profiled initiating transcripts in two addiction-related brain regions, the prefrontal cortex (PFC) and the nucleus accumbens (NAc), from rats that were never exposed to drugs or were subjected to prolonged abstinence after oxycodone or cocaine intravenous self-administration (IVSA). Interrogating over 100,000 active transcription start regions (TSRs) revealed that most TSRs had hallmarks of bonafide enhancers and highlighted the KLF/SP1, RFX, and AP1 transcription factors families as central to establishing brain-specific gene regulatory programs. Analysis of rats with addiction-like behaviors versus controls identified addiction-associated repression of transcription at regulatory enhancers recognized by nuclear receptor subfamily 3 group C (NR3C) factors, including glucocorticoid receptors. Cell-type deconvolution analysis using snATAC-seq uncovered a potential role of glial cells in driving the gene regulatory programs associated with addiction-related phenotypes. These findings highlight the power of advanced transcriptomics methods to provide insight into how addiction perturbs gene regulatory programs in the brain.
Dutour A, etal., Hum Mol Genet. 2011 Oct 1;20(19):3779-86. doi: 10.1093/hmg/ddr294. Epub 2011 Jun 30.
Constitutional laminopathies, such as the Dunnigan familial partial lipodystrophy, are severe diseases caused by mutations in A-type lamins and share several features with metabolic syndrome (MS). In this study, we hypothesized that MS may be, in some cases, a mild form of laminopathies and use the
abnormal cell nucleus phenotype observed in these diseases as a primary screening test in patients suffering from common MS. Nuclear shape and lamin A nucleoplasmic distribution abnormalities were systematically searched in lymphoblastoid cells of 87 consecutive patients with MS. In parallel, five genes encoding either the A-type lamins or the enzymes of the lamin A maturation pathway were systematically sequenced (LMNA, ZMPSTE24, ICMT, FNTA and FNTB). We identified 10 MS patients presenting abnormal nuclear shape and disturbed lamin A/C nuclear distribution. These patients were not clinically different from those without nuclear abnormalities except that they were younger, and had higher triglyceridemia and SGPT levels. Three of them carry a heterozygous mutation in LMNA or in ZMPSTE24, a gene encoding one of the lamin A processing enzymes. All three mutations are novel missense mutations predicted to be damaging. Both lymphoblastoid cells and skin fibroblasts from the patient carrying the mutation in ZMPSTE24, showed accumulation of lamin A precursor, indicating an alteration of the lamin A processing, confirmed by functional study. Together, these results show for the first time, that a significant proportion of MS patients exhibits laminopathies and suggest that systematic investigation of lamin A and its partners should be performed at the diagnosis of this syndrome.
Dutmer CM, etal., J Clin Immunol. 2015 Nov;35(8):754-60. doi: 10.1007/s10875-015-0207-8. Epub 2015 Oct 29.
PURPOSE: Hypomorphic mutations in RAG1 and RAG2 are associated with significant clinical heterogeneity and symptoms of immunodeficiency or autoimmunity may be late in appearance. As a result, immunosuppressive medications may be introduced that can have life-threatening consequences. We describe a
previously healthy 13-month-old girl presenting with rash and autoimmune hemolytic anemia, while highlighting the importance of vigilance and consideration of an underlying severe immunodeficiency disease prior to instituting immunosuppressive therapy. METHODS: Given clinical deterioration of the patient and a temporal association with recently administered vaccinations, virus genotyping was carried out via 4 real-time Forster Resonance Energy Transfer PCR protocols targeting vaccine-associated single nucleotide polymorphisms. Genomic DNA was extracted from whole blood and analyzed via the next-generation sequencing method of sequencing-by-synthesis. Immune function studies included immunophenotyping of peripheral blood lymphocytes, mitogen-induced proliferation and TLR ligand-induced production of TNFalpha. Analysis of recombination activity of wild-type and mutant RAG2 constructs was performed. RESULTS: Virus genotyping revealed vaccine-strain VZV, mumps, and rubella. Next-generation sequencing identified heterozygosity for RAG2 R73H and P180H mutations. Profound lymphopenia was associated with intense corticosteroid therapy, with some recovery after steroid reduction. Residual, albeit low, RAG2 protein activity was demonstrated. CONCLUSIONS: Because of the association of RAG deficiency with late-onset presentation and autoimmunity, live virus vaccination and immunosuppressive therapies are often initiated and can result in negative consequences. Here, hypomorphic RAG2 mutations were linked to disseminated vaccine-strain virus infections following institution of corticosteroid therapy for autoimmune hemolytic anemia.
Astrocytes play a predominant role in energy metabolism and in the catabolism of gamma-aminobutyric acid (GABA) and glutamate, neurotransmitters critically involved in epileptic processes. We show specific astrocytic alterations in the genetic absence epilepsy rats from Strasbourg (GAERS). Spontane
ous absence seizures appear in this strain in the cortex and thalamus after the age of 1 month. In these brain structures, we demonstrate increased GFAP expression in both adult and young GAERS, suggesting that reactive astrocytes are already present before the onset of seizures. Glutamate dehydrogenase (GDH) and glutamine synthetase (GS), which are localized mainly in astrocytes and involved in glutamate catabolism, are shown to be differentially altered. GDH expression was increased in the thalamus of both young and adult GAERS and in the cortex of young GAERS. GS expression was slightly decreased in the thalamus of young GAERS. These astrocytic modifications are not adaptive responses to seizures, as the modifications appear before the development of absence seizures. Thus, astrocytes might be involved in the neuronal processes giving rise to epileptic seizures in this strain.
Dutriez I, etal., Experientia. 1992 Mar 15;48(3):290-300.
Neutral endopeptidase (NEP, enkephalinase, CALLA) which is present in various neural and non-neural tissues, is able to cleave a variety of regulatory peptides. The distribution of NEP has been studied during rat pre- and post-natal development by autoradiography after in vitro binding of the tritia
ted inhibitor [3H]HACBO-Gly to whole-body and organ sections. In the central nervous system (CNS), where the presence of NEP has been related to the termination of the action of enkephalins, the external layer of the olfactory bulbs is the only structure prominently labeled before birth. Other CNS structures rich in NEP in the adult, such as the nigrostriatal tract, are progressively labeled after birth. Outside the CNS, the progressive appearance of NEP in the kidney, the lungs and the salivary glands suggests its concomitant involvement in adult physiological functions, including fluid balance control, possibly by cleaving the atrial natriuretic peptide (ANP) and other peptides. On the other hand, transient or enhanced expression of NEP is observed during the development of several organs such as the sensory organs, the heart and the major blood vessels, the intestine, the bones and the genital tubercle. In addition to the still incompletely known physiological functions of the enzyme, the developmental pattern of its expression in several tissues strongly suggests a modulatory role for NEP in the ontogeny of a large number of organs.
PML (Promyelocytic Leukemia protein), also known as TRIM19, belongs to the family of tripartite motif (TRIM) proteins. PML is mainly expressed in the nucleus, where it forms dynamic structures known as PML nuclear bodies that recruit many other proteins, such as Sp100 and Daxx. While the role of PML
/TRIM19 in antiviral defense is well documented, its effect on HIV-1 infection remains unclear. Here we show that infection by HIV-1 and other retroviruses triggers the formation of PML cytoplasmic bodies, as early as 30 minutes post-infection. Quantification of the number and size of PML cytoplasmic bodies revealed that they last approximately 8 h, with a peak at 2 h post-infection. PML re-localization is blocked by reverse-transcription inhibitors and is not observed following infection with unrelated viruses, suggesting it is specifically triggered by retroviral reverse-transcription. Furthermore, we show that PML interferes with an early step of retroviral infection since PML knockdown dramatically increases reverse-transcription efficiency. We demonstrate that PML does not inhibit directly retroviral infection but acts through the stabilization of one of its well-characterized partners, Daxx. In the presence of PML, cytoplasmic Daxx is found in the vicinity of incoming HIV-1 capsids and inhibits reverse-transcription. Interestingly, Daxx not only interferes with exogenous retroviral infections but can also inhibit retrotransposition of endogenous retroviruses, thus identifying Daxx as a broad cellular inhibitor of reverse-transcription. Altogether, these findings unravel a novel antiviral function for PML and PML nuclear body-associated protein Daxx.
Dutrieux J, etal., Retrovirology. 2015 Mar 24;12:28. doi: 10.1186/s12977-015-0155-7.
BACKGROUND: The TRIM5alpha restriction factor interferes with retroviral infections by inhibiting an early step of viral replication. TRIM5alpha activity was recently proposed to be regulated by the SUMO machinery and one SUMO consensus conjugation site as well as three putative SUMO interacting mo
tifs (SIMs) were identified within TRIM5alpha sequence. Whereas mutation of the SIM sequences was found to abolish TRIM5alpha antiviral activity, mutation of the consensus SUMO conjugation site did not affect its restriction capacity, although this putative site has never been shown to be actually a SUMO substrate. FINDINGS: Here we further demonstrate that TRIM5alpha relies on the SUMO machinery to promote restriction, since SUMO1 overexpression enhances TRIM5alpha-mediated retroviral inhibition whereas knockdown of SUMO1 or E2 SUMO conjugating enzyme Ubc9 prevents restriction. Furthermore, we show for the first time that TRIM5alpha is SUMOylated both in vitro and in cellulo and that Lysine 10 is the main SUMOylation site. Mutation of the consensus SUMO conjugation motif in position 10 abrogated SUMOylation at this position, but did not disrupt TRIM5alpha antiviral activity. CONCLUSIONS: Altogether, our results confirm that the SUMO machinery is involved in TRIM5alpha-mediated retroviral restriction, and demonstrate that TRIM5alpha is a SUMO 1 and SUMO 2 substrate. The inability to abrogate TRIM5alpha antiviral activity by mutating its main SUMO conjugation motif supports the notion that non-covalent interaction with SUMO or SUMOylated proteins rather than TRIM5alpha direct SUMOylation is required.
Dutriez-Casteloot I, etal., Horm Metab Res. 2008 Apr;40(4):257-61.
Maternal undernutrition leads to intrauterine growth retardation and predisposes to the development of pathologies in adulthood. The hypothalamo-pituitary-adrenal axis is a major target of early-life programming. We showed previously that perinatal maternal 50% food restriction leads to hypothalamo-
pituitary-adrenal axis hyperactivity and disturbs glucocorticoid feedback in adult male rats. To try to better understand these alterations, we studied several factors involved in corticosterone sensitivity. We showed that unlike the restricted expression of 11 beta-HSD2 mRNA, the 11 beta-HSD1, glucocorticoid, and mineralocorticoid receptor genes are widely distributed in rat. In contrast to the hypothalamus, we confirmed that maternal undernutrition modulates hippocampal corticosterone receptor balance and leads to increased 11 beta-HSD1 gene expression. In the pituitary, rats exhibited a huge increase in both mRNA and mineralocorticoid receptor binding capacities as well as decreased 11 beta-HSD1/11 beta-HSD2 gene expression. Using IN SITU hybridization, we showed that the mineralocorticoid receptor gene was expressed in rat corticotroph cells and by other adenopituitary cells. In the adrenal gland, maternal food restriction decreased 11beta-HSD2 mRNA. This study demonstrated that maternal food restriction has both long-term and tissue-specific effects on gene expression of factors involved in glucocorticoid sensitivity and that it could contribute, via glucocorticoid excess, to the development of adult diseases.
Hu M, etal., Eye (Lond). 1999 Jun;13 ( Pt 3a):309-13.
PURPOSE: To investigate cytokine mRNA expression and the influence of acyclovir and tetrandrine on that expression in the corneas of mice infected with herpes simplex virus type 1 (HSV-1). METHODS: Male BALB/c mice were infected in the right cornea with HSV-1. The corneas were harvested from control
normal mice and from untreated, acyclovir-treated and tetrandrine-treated mice 14 days after infection. The infected corneas of each group were divided into inflamed and uninflamed depending on clinical observation. After total mRNA extraction from the corneas, gene expression of interleukin 1 beta (IL-1 beta), IL-6, tumour necrosis factor alpha (TNF-alpha) and transforming growth factor (beta (TGF-beta) was analysed by reverse transcription polymerase chain reaction. RESULTS: No mRNA expression of the cytokines was found in normal corneas. IL-1 beta and TNF-alpha mRNA was seen in inflamed corneas, while mRNA expression of IL-6 and relatively weaker TGF-beta mRNA expression were found both in inflamed corneas and in infected but uninflamed corneas treated with acyclovir. TNF-alpha mRNA was present in the uninflamed corneas of tetrandrine-treated mice. No influence of either agent was found on TGF-beta gene expression. CONCLUSIONS: The results suggest that local IL-1 beta and TNF-alpha gene expression is required for corneal inflammation, whereas IL-6 and TGF-beta may exert antiviral and inflammation regulatory activities in HSV corneal infection.
Sanyal M, etal., Clin Immunol. 2015 Dec;161(2):355-65. doi: 10.1016/j.clim.2015.10.005. Epub 2015 Oct 21.
Schimke immuno-osseous dysplasia (SIOD) is an autosomal recessive, fatal childhood disorder associated with skeletal dysplasia, renal dysfunction, and T-cell immunodeficiency. This disease is linked to biallelic loss-of-function mutations of the SMARCAL1 gene. Although recurrent infection, due to T-
cell deficiency, is a leading cause of morbidity and mortality, the etiology of the T-cell immunodeficiency is unclear. Here, we demonstrate that the T cells of SIOD patients have undetectable levels of protein and mRNA for the IL-7 receptor alpha chain (IL7Ralpha) and are unresponsive to stimulation with IL-7, indicating a loss of functional receptor. No pathogenic mutations were detected in the exons of IL7R in these patients; however, CpG sites in the IL7R promoter were hypermethylated in SIOD T cells. We propose therefore that the lack of IL7Ralpha expression, associated with hypermethylation of the IL7R promoter, in T cells and possibly their earlier progenitors, restricts T-cell development in SIOD patients.
Ding L, etal., Nature. 2008 Oct 23;455(7216):1069-75. doi: 10.1038/nature07423.
Determining the genetic basis of cancer requires comprehensive analyses of large collections of histopathologically well-classified primary tumours. Here we report the results of a collaborative study to discover somatic mutations in 188 human lung adenocarcinomas. DNA sequencing of 623 genes with
known or potential relationships to cancer revealed more than 1,000 somatic mutations across the samples. Our analysis identified 26 genes that are mutated at significantly high frequencies and thus are probably involved in carcinogenesis. The frequently mutated genes include tyrosine kinases, among them the EGFR homologue ERBB4; multiple ephrin receptor genes, notably EPHA3; vascular endothelial growth factor receptor KDR; and NTRK genes. These data provide evidence of somatic mutations in primary lung adenocarcinoma for several tumour suppressor genes involved in other cancers--including NF1, APC, RB1 and ATM--and for sequence changes in PTPRD as well as the frequently deleted gene LRP1B. The observed mutational profiles correlate with clinical features, smoking status and DNA repair defects. These results are reinforced by data integration including single nucleotide polymorphism array and gene expression array. Our findings shed further light on several important signalling pathways involved in lung adenocarcinoma, and suggest new molecular targets for treatment.
Adipose tissue is crucial for the maintenance of energy and metabolic homeostasis and its deregulation can lead to obesity and type II diabetes (T2D). Using gene disruption in the mouse, we discovered a function for a RhoA-specific guanine nucleotide exchange factor PDZ-RhoGEF (Arhgef11) in white ad
ipose tissue biology. While PDZ-RhoGEF was dispensable for a number of RhoA signaling-mediated processes in mouse embryonic fibroblasts, including stress fiber formation and cell migration, it's deletion led to a reduction in their proliferative potential. On a whole organism level, PDZ-RhoGEF deletion resulted in an acute increase in energy expenditure, selectively impaired early adipose tissue development and decreased adiposity in adults. PDZ-RhoGEF-deficient mice were protected from diet-induced obesity and T2D. Mechanistically, PDZ-RhoGEF enhanced insulin/IGF-1 signaling in adipose tissue by controlling ROCK-dependent phosphorylation of the insulin receptor substrate-1 (IRS-1). Our results demonstrate that PDZ-RhoGEF acts as a key determinant of mammalian metabolism and obesity-associated pathologies.
Age-associated deficits in learning and memory are closely correlated with impairments of synaptic plasticity. Analysis of N-methyl-D-aspartate receptor (NMDAr)-dependent long-term potentiation (LTP) in CA1 hippocampal slices indicates that the glial-derived neuromodulator D-serine is required for t
he induction of synaptic plasticity. During aging, the content of D-serine and the expression of its synthesizing enzyme serine racemase are significantly decreased in the hippocampus. Impaired LTP and NMDAr-mediated synaptic potentials in old rats are rescued by exogenous D-serine. These results highlight the critical role of glial cells and presumably astrocytes, through the availability of D-serine, in the deficits of synaptic mechanisms of learning and memory that occur in the course of aging.
Slavotinek AM, etal., Am J Med Genet A. 2004 Aug 15;129(1):69-72.
We report a 19-year-old, non-Amish Caucasian female patient with primary amenorrhea caused by complete lack of Mullerian fusion with vaginal agenesis or Mullerian aplasia (MA), postaxial polydactyly (PAP), and tetralogy of Fallot. The genital tract anomaly of MA with and without renal or skeletal an
omalies comprises Mayer-Rokitansky-Kuster-Hauser syndrome, which has not been reported with tetralogy of Fallot. The phenotypic triad of anomalies most closely resembled McKusick-Kaufman syndrome (MKS; OMIM 236700), a rare multiple congenital anomaly syndrome comprised of hydrometrocolpos (HMC), PAP, and congenital heart malformation that is inherited in an autosomal recessive pattern. While upper reproductive tract anomalies have not been reported with MKS, they have been reported with Bardet-Biedl syndrome (BBS), a syndrome that significantly overlaps with MKS. Both MKS and BBS can be caused by mutations in the MKKS or BBS6 gene on chromosome 20p12 and BBS is also associated with mutations in other genes (BBS1, BBS2, BBS4, and BBS7). To address this heterogenity, we sequenced the causative genes in MKS and BBS but no mutations in these five genes were identified. Fluorescence in situ hybridization (FISH) excluded large deletions of chromosome 20p12 and microsatellite marker studies confirmed biparental inheritance for all of the known BBS loci. The dual midline fusion defects of tetralogy of Fallot and MA suggests that either this patient has a unique syndrome with a distinct genetic etiology or that she has a genetically heterogeneous or variant form of MKS.
OBJECTIVE : To localize quantitative trait loci (QTL) in an animal model that is potentially relevant to human hypertension. DESIGN AND METHODS : Four congenic strains have been constructed by replacing various segments of the Dahl salt-sensitive (S) rat by those of the Lewis (LEW) rat. A marker-ass
isted approach was employed to facilitate this process. When these congenic strains were established, their blood pressures (BPs) were measured by telemetry and compared with that of the S rat. Moreover, a search was conducted to find possible intermediate phenotypes linking the BP effects of the QTL and other physiological traits. RESULTS : Two BP QTL, designated as QTL1 and QTL2, have been mapped to the regions of 4.2 centiMorgans (cM) and less than 12.1 cM respectively on rat chromosome 10. The effects of both QTL correlate with cardiac, left ventricular and aortic hypertrophy. The effect of QTL1 is also associated with renal hypertrophy. CONCLUSION : The current study proved that multiple QTL exist in the region of Dahl rat chromosome 10. The identification of these QTL may help unravel the mechanisms underlying the pathogenesis of certain QTL in humans.
Photoaffinity labeling is a positive function approach that has been used in an effort to identify the cocaine-binding site on the dopamine transporter (DAT). Radioactive and non-radioactive analogs of cocaine and other dopamine uptake blockers are used to irreversibly label the DAT ligand-binding s
ite and the protein is subjected to chemical or enzymatic treatments that cleave at specific amino acid residues. Analysis of cleavage products from radioactively photolabeled DAT using epitope-specific immunoprecipitation, gel electrophoresis, and autoradiography has identified the site of origin in the primary sequence of labeled fragments as small as 4 kDa. More precise localization of the site of labeling is done by subjecting photolabeled DAT to parallel or serial digestion with multiple cleavage methods, followed by analysis of radiolabeled peptides by reverse-phase HPLC. Fragment retention times are compared to calculated retention times of predicted digest peptides and to chemically or photochemically labeled synthetic peptides. The presence of authentic DAT sequence in HPLC fractions of digests from DAT labeled with non-radioactive ligands is further supported by MALDI and nanoelectrospray mass spectrometry. Using these methods we have identified two distinct regions of DAT that interact with multiple structurally related and diverse irreversible ligands, suggesting that these regions may be involved in the formation of ligand binding sites.
Wang X, etal., Nat Commun. 2016 May 10;7:11459. doi: 10.1038/ncomms11459.
Human neuroimaging studies suggest that aberrant neural connectivity underlies behavioural deficits in autism spectrum disorders (ASDs), but the molecular and neural circuit mechanisms underlying ASDs remain elusive. Here, we describe a complete knockout mouse model of the autism-associated Shank3 g
ene, with a deletion of exons 4-22 (Deltae4-22). Both mGluR5-Homer scaffolds and mGluR5-mediated signalling are selectively altered in striatal neurons. These changes are associated with perturbed function at striatal synapses, abnormal brain morphology, aberrant structural connectivity and ASD-like behaviour. In vivo recording reveals that the cortico-striatal-thalamic circuit is tonically hyperactive in mutants, but becomes hypoactive during social behaviour. Manipulation of mGluR5 activity attenuates excessive grooming and instrumental learning differentially, and rescues impaired striatal synaptic plasticity in Deltae4-22(-/-) mice. These findings show that deficiency of Shank3 can impair mGluR5-Homer scaffolding, resulting in cortico-striatal circuit abnormalities that underlie deficits in learning and ASD-like behaviours. These data suggest causal links between genetic, molecular, and circuit mechanisms underlying the pathophysiology of ASDs.
Audrain M, etal., Mol Neurodegener. 2016 Jan 12;11:5. doi: 10.1186/s13024-016-0070-y.
BACKGROUND: Alzheimer's disease (AD) is the most frequent form of dementia in the elderly and no effective treatment is currently available. The mechanisms triggering AD onset and progression are still imperfectly dissected. We aimed at deciphering the modifications occurring in vivo during the ver
y early stages of AD, before the development of amyloid deposits, neurofibrillary tangles, neuronal death and inflammation. Most current AD models based on Amyloid Precursor Protein (APP) overproduction beginning from in utero, to rapidly reproduce the histological and behavioral features of the disease within a few months, are not appropriate to study the early steps of AD development. As a means to mimic in vivo amyloid APP processing closer to the human situation in AD, we used an adeno-associated virus (AAV)-based transfer of human mutant APP and Presenilin 1 (PS1) genes to the hippocampi of two-month-old C57Bl/6 J mice to express human APP, without significant overexpression and to specifically induce its amyloid processing. RESULTS: The human APP, betaCTF and Abeta42/40 ratio were similar to those in hippocampal tissues from AD patients. Three months after injection the murine Tau protein was hyperphosphorylated and rapid synaptic failure occurred characterized by decreased levels of both PSD-95 and metabolites related to neuromodulation, on proton magnetic resonance spectroscopy ((1)H-MRS). Astrocytic GLT-1 transporter levels were lower and the tonic glutamatergic current was stronger on electrophysiological recordings of CA1 hippocampal region, revealing the overstimulation of extrasynaptic N-methyl D-aspartate receptor (NMDAR) which precedes the loss of long-term potentiation (LTP). These modifications were associated with early behavioral impairments in the Open-field, Y-maze and Morris Mater Maze tasks. CONCLUSIONS: Altogether, this demonstrates that an AD-like APP processing, yielding to levels of APP, betaCTF and Abeta42/Abeta40 ratio similar to those observed in AD patients, are sufficient to rapidly trigger early steps of the amyloidogenic and Tau pathways in vivo. With this strategy, we identified a sequence of early events likely to account for disease onset and described a model that may facilitate efforts to decipher the factors triggering AD and to evaluate early neuroprotective strategies.
Chatterjee A, etal., J Cell Physiol. 2011 Oct;226(10):2543-54. doi: 10.1002/jcp.22599.
Cardiac hypertrophy leading to eventual heart failure is the most common cause of mortality throughout the world. The triggering mechanisms for cardiac hypertrophy are not clear but both apoptosis and cell proliferation have been reported in sections of failing hearts. In this study, we utilized bot
h angiotensin II (AngII) treatment of cardiomyocytes and aortic ligation in rats (Rattus norvegicus, Wistar strain) for induction of hypertrophy to understand the cellular factors responsible for activation of apoptotic or anti-apoptotic pathway. Hypertrophy markers (ANF, beta-MHC), apoptotic proteins (Bax, Bad, Fas, p53, caspase-3, PARP), and anti-apoptotic or cell proliferation marker proteins (Bcl2, NF-kappaB, Ki-67) were induced significantly during hypertrophy, both in vitro as well as in vivo. Co-localization of both active caspase-3 and Ki-67 was observed in hypertrophied myocytes. p53 and NF-kappaBp65 binding to co-activator p300 was also increased in AngII treated myocytes. Inhibition of p53 resulted in downregulation of apoptosis, NF-kappaB activation, and NF-kappaB-p300 binding; however, NF-kappaB inhibition did not inhibit apoptosis or p53-p300 binding. Blocking of either p53 or NF-kappaB by specific inhibitors resulted in decrease in cell proliferation and hypertrophy markers, suggesting that p53 initially binds to p300 and then this complex recruits NF-kappaB. Thus, these results indicate the crucial role of p53 in regulating both apoptotic and cell proliferation during hypertrophy.
Bhattacharyya SS, etal., Zhong Xi Yi Jie He Xue Bao. 2010 Jul;8(7):645-54.
OBJECTIVE: Anti-cancer potentials of scopoletin (7-hydroxy-6-methoxy coumarin) separated from plant extract (Gelsemium sempervirens) were demonstrated earlier from our in vitro studies. In the present study, its in vivo effects have been evaluated in mice. METHODS: Mice were chronically administered
7,12-dimethylbenz [a] anthracene (DMBA) once a week and croton oil twice a week on their back, which resulted in the development of fully grown finger-like projections (papilloma) after 24 weeks. Two subgroups of mice (drug-treated) were treated with two doses of scopoletin (50 mg and 100 mg/kg body weight) respectively while control received 2% ethyl alcohol (the "vehicle" of scopoletin). After the 24-week drug administration, expressions of several key receptors such as aryl hydrocarbon receptor (AhR) and signal proteins like p53, cytochrome P450 1A1 (CYP1A1), proliferating cell nuclear antigen (PCNA), signal transducer and activator of transcription-3 (Stat-3), survivin, matrix metalloproteinase-2 (MMP-2), cyclin D1, c-myc, tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) and caspase-3, and some anti-oxidant markers were studied. Lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase and glutathione-s-transferase in supernatant were also detected. RESULTS: Carcinogens induced toxicity, and over-expression of AhR, CYP1A1, PCNA, Stat-3, survivin, MMP-2, cyclin D1 and c-myc and down-regulation of p53, caspase-3 and TIMP-2. In mice treated with scopoletin, the expressions of these proteins and toxicity biomarkers were reverted. CONCLUSION: Since AhR is known to be ligand-activated by DMBA to release signals for several downstream proteins initiating reactive oxygen species generation, the down-regulation of AhR by scopoletin appeared to play a significant role in subsequent down-regulation of some key signal proteins. One possible mechanism of down-regulation of AhR may be through competitive inhibition by scopoletin. Mitogen-activated protein kinases may also have some critical role. This compound can be considered as a possible candidate for chemoprevention.
Shlyakhtenko LS, etal., Sci Rep. 2015 Oct 27;5:15648. doi: 10.1038/srep15648.
APOBEC3G (A3G) protein has antiviral activity against HIV and other pathogenic retroviruses. A3G has two domains: a catalytic C-terminal domain (CTD) that deaminates cytidine, and a N-terminal domain (NTD) that binds to ssDNA. Although abundant information exists about the biological activities of
A3G protein, the interplay between sequence specific deaminase activity and A3G binding to ssDNA remains controversial. We used the topographic imaging and force spectroscopy modalities of Atomic Force Spectroscopy (AFM) to characterize the interaction of A3G protein with deaminase specific and nonspecific ssDNA substrates. AFM imaging demonstrated that A3G has elevated affinity for deaminase specific ssDNA than for nonspecific ssDNA. AFM force spectroscopy revealed two distinct binding modes by which A3G interacts with ssDNA. One mode requires sequence specificity, as demonstrated by stronger and more stable complexes with deaminase specific ssDNA than with nonspecific ssDNA. Overall these observations enforce prior studies suggesting that both domains of A3G contribute to the sequence specific binding of ssDNA.
BACKGROUND: Previous studies have investigated associations between apolipoprotein E (APOE)-varepsilon4 allele status and acetylcholinesterase inhibitor treatment response in patients with Alzheimer's disease. The ability to draw definitive conclusions regarding the effect of APOE-varepsilon4 genoty
pe on treatment response has been hindered by inconsistent results among studies and methodological limitations that restrict interpretation of study findings. OBJECTIVE: To determine whether APOE-varepsilon4 carrier status influences the magnitude of change in 13-item Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog) score associated with acetylcholinesterase inhibitor treatment (i.e., donepezil). METHODS: Analyses were performed using pooled data from the donepezil and placebo treatment arms of three consecutive, similarly designed, 12-week, multi-national, randomized clinical studies that enrolled patients with mild-to-moderate Alzheimer's disease. Correlations between APOE-varepsilon4 carrier status and ADAS-cog scores were evaluated using analysis of covariance. RESULTS: No appreciable interaction between donepezil response and APOE-varepsilon4 carrier status or copy number was detected. Both carriers and non-carriers of APOE-varepsilon4 who received donepezil experienced significant improvements from baseline in ADAS-cog score versus placebo (p < 0.05). Change from baseline to final observation in the donepezil treatment group was - 2.95 for APOE-varepsilon4 carriers and - 4.09 for non-carriers (p = 0.23). In contrast, non-carriers of APOE-varepsilon4 in the placebo treatment group exhibited a greater improvement from baseline versus carriers (-2.38 versus - 0.60, p = 0.05). CONCLUSION: Within this population, APOE genotype had no statistically significant effect on cognitive response to donepezil treatment; however, APOE-varepsilon4 allele status was associated with a difference in the magnitude of the change in ADAS-cog of placebo-treated patients.
Dasgupta S, etal., Indian J Med Res. 2015 Sep;142(3):276-85. doi: 10.4103/0971-5916.166587.
BACKGROUND & OBJECTIVES: The Vitamin-D receptor (VDR) regulates vitamin D levels and calcium metabolism in the body and these are known to be associated with endocrine dysfunctions, insulin resistance and type-2 diabetes in polycystic ovarian syndrome (PCOS). Studies on VDR polymorphisms among PCOS
women are sparse. We undertook this study to investigate the association pattern of VDR polymorphisms (Cdx2, Fok1, Apa1 and Taq1) with PCOS among Indian women. METHODS: For the present study, 250 women with PCOS and 250 normal healthy control women were selected from Hyderabad city, Telangana, India. The four VDR polymorphisms were genotyped and analysed using ASM-PCR (allele specific multiple PCR) and PCR-RFLP (restriction fragment length polymorphism). RESULTS: The genotype and allele frequency distributions of only Cdx2 showed significant difference between the PCOS cases and control women, indicating protective role of this SNP against PCOS phenotype. However, significant association was observed between VDR genotypes and some of the PCOS specific clinical/biochemical traits. For example, Fok1 showed a significant genotypic difference for the presence of infertility and Cdx2 genotpes showed association with testosterone levels. Further, the two haplotypes, ACCA and ACTA, were found to be significantly associated with PCOS indicating haplotype specific risk. INTERPRETATION & CONCLUSIONS: Although VDR polymorphisms have not shown significant association with PCOS, in view of functional significance of the SNPs considered, one cannot yet rule out the possibility of their association with PCOS. Further, specifically designed studies on large cohorts are required to conclusively establish the role of VDR polymorphisms in PCOS, particularly including data on vitamin D levels.
Alzheimer's disease (AD) is characterized by both amyloid and Tau pathologies. The amyloid component and altered cholesterol metabolism are closely linked, but the relationship between Tau pathology and cholesterol is currently unclear. Brain cholesterol is synthesized in situ and cannot cross the
blood-brain barrier: to be exported from the central nervous system into the blood circuit, excess cholesterol must be converted to 24S-hydroxycholesterol by the cholesterol 24-hydroxylase encoded by the CYP46A1 gene. In AD patients, the concentration of 24S-hydroxycholesterol in the plasma and the cerebrospinal fluid are lower than in healthy controls. The THY-Tau22 mouse is a model of AD-like Tau pathology without amyloid pathology. We used this model to investigate the potential association between Tau pathology and CYP46A1 modulation. The amounts of CYP46A1 and 24S-hydroxycholesterol in the hippocampus were lower in THY-Tau22 than control mice. We used an adeno-associated virus (AAV) gene transfer strategy to increase CYP46A1 expression in order to investigate the consequences on THY-Tau22 mouse phenotype. Injection of the AAV-CYP46A1 vector into the hippocampus of THY-Tau22 mice led to CYP46A1 and 24S-hydroxycholesterol content normalization. The cognitive deficits, impaired long-term depression and spine defects that characterize the THY-Tau22 model were completely rescued, whereas Tau hyperphosphorylation and associated gliosis were unaffected. These results argue for a causal link between CYP46A1 protein content and memory impairments that result from Tau pathology. Therefore, CYP46A1 may be a relevant therapeutic target for Tauopathies and especially for AD.
Liu YT, etal., Am J Pathol. 2007 Dec;171(6):1978-88. Epub 2007 Nov 30.
Ferric nitrilotriacetate induces oxidative renal tubular damage via Fenton-reaction, which subsequently leads to renal cell carcinoma (RCC) in rodents. Here, we used gene expression microarray and array-based comparative genomic hybridization analyses to find target oncogenes in this model. At the c
ommon chromosomal region of amplification (4q22) in rat RCCs, we found ptprz1, a tyrosine phosphatase (also known as protein tyrosine phosphatase zeta or receptor tyrosine phosphatase beta) highly expressed in the RCCs. Analyses revealed genomic amplification up to eightfold. Despite scarcity in the control kidney, the amounts of PTPRZ1 were increased in the kidney after 3 weeks of oxidative stress, and mRNA levels were increased 16 approximately 552-fold in the RCCs. Network analysis of the expression revealed the involvement of the beta-catenin pathway in the RCCs. In the RCCs, dephosphorylated beta-catenin was translocated to nuclei, resulting in the expression of its target genes cyclin D1, c-myc, c-jun, fra-1, and CD44. Furthermore, knockdown of ptprz1 with small interfering RNA (siRNA), in FRCC-001 and FRCC-562 cell lines established from the induced RCCs, decreased the amounts of nuclear beta-catenin and suppressed cellular proliferation concomitant with a decrease in the expression of target genes. These results demonstrate that chronic oxidative stress can induce genomic amplification of ptprz1, activating beta-catenin pathways without the involvement of Wnt signaling for carcinogenesis. Thus, iron-mediated persistent oxidative stress confers an environment for gene amplification.
Singh N, etal., Dev Dyn. 2016 Feb;245(2):114-22. doi: 10.1002/dvdy.24361. Epub 2015 Dec 6.
BACKGROUND: In Ts65Dn, a mouse model of Down syndrome (DS), brain and craniofacial abnormalities that parallel those in people with DS are linked to an attenuated cellular response to sonic hedgehog (SHH) signaling. If a similarly reduced response to SHH occurs in all trisomic cells, then chronic up
-regulation of the pathway might have a positive effect on development in trisomic mice, resulting in amelioration of the craniofacial anomalies. RESULTS: We crossed Ts65Dn with Ptch1(tm1Mps/+) mice and quantified the craniofacial morphology of Ts65Dn;Ptch(+/-) offspring to assess whether a chronic up-regulation of the SHH pathway rescued DS-related anomalies. Ts65Dn;Ptch1(+/-) mice experience a chronic increase in SHH in SHH-receptive cells due to haploinsufficiency of the pathway suppressor, Ptch1. Chronic up-regulation had minimal effect on craniofacial shape and did not correct facial abnormalities in Ts65Dn;Ptch(+/-) mice. We further compared effects of this chronic up-regulation of SHH with acute pathway stimulation in mice treated on the day of birth with a SHH pathway agonist, SAG. We found that SHH affects facial morphology differently based on chronic vs. acute postnatal pathway up-regulation. CONCLUSIONS: Our findings have implications for understanding the function of SHH in craniofacial development and for the potential use of SHH-based agonists to treat DS-related abnormalities. Developmental Dynamics 245:114-122, 2016. (c) 2015 Wiley Periodicals, Inc.
Exposure to psychosocial stress is a risk factor for many diseases, including atherosclerosis. Although incompletely understood, interaction between the psyche and the immune system provides one potential mechanism linking stress and disease inception and progression. Known cross-talk between the br
ain and immune system includes the hypothalamic-pituitary-adrenal axis, which centrally drives glucocorticoid production in the adrenal cortex, and the sympathetic-adrenal-medullary axis, which controls stress-induced catecholamine release in support of the fight-or-flight reflex. It remains unknown, however, whether chronic stress changes hematopoietic stem cell activity. Here we show that stress increases proliferation of these most primitive hematopoietic progenitors, giving rise to higher levels of disease-promoting inflammatory leukocytes. We found that chronic stress induced monocytosis and neutrophilia in humans. While investigating the source of leukocytosis in mice, we discovered that stress activates upstream hematopoietic stem cells. Under conditions of chronic variable stress in mice, sympathetic nerve fibers released surplus noradrenaline, which signaled bone marrow niche cells to decrease CXCL12 levels through the beta3-adrenergic receptor. Consequently, hematopoietic stem cell proliferation was elevated, leading to an increased output of neutrophils and inflammatory monocytes. When atherosclerosis-prone Apoe(-/-) mice were subjected to chronic stress, accelerated hematopoiesis promoted plaque features associated with vulnerable lesions that cause myocardial infarction and stroke in humans.
Moujahidine M, etal., Hypertens Res 2004 Mar;27(3):203-12.
Chromosomes (Chr) 10 and 16 of the Dahl salt-sensitive (S) rat harbor quantitative trait loci (QTLs) for blood pressure (BP). To facilitate gene discovery of these QTLs, gene profiling based on microarrays was combined with fine QTL mapping to identify potential candidate genes that are differential
ly expressed. First, the region harboring the BP QTL on Chr 16 was narrowed by comparative congenic mapping. In this endeavor, a number of new chromosome markers were generated and used to physically define the chromosome interval in question. Second, in an effort to minimize the costs of gene profiling without sacrificing the chance of gene discovery, a combination congenic strain was produced by replacing one segment of Chr 10 along with one segment of Chr 16 of the hypertensive S rat by those of the normotensive Lewis (LEW) rat. Both of these regions are known to contain BP QTLs. Third, kidneys of this combination congenic strain and the S strain were employed for expression profiling studies. Finally, a comparison between the two strains yielded a number of potentially differentially expressed candidates. Six Established Sequence Tags (ESTs)/genes among them were located in Chr 10 regions and 1 was found in a Chr 16 region, and the genetic make-ups of all these regions were shown to be different between S and LEW. However, none of these ESTs/genes identified by gene profiling were located in an interval containing a QTL. Thus, the present study highlights the importance of correlating the results of gene expression profiling with fine congenic mapping.
Grondin M, etal., Physiol Genomics 2005 Mar 21;21(1):112-6. Epub 2005 Jan 4.
Linkage studies suggested that a quantitative trait locus (QTL) for blood pressure (BP) was present in a region on chromosome 17 (Chr 17) of Dahl salt-sensitive (DSS) rats. A subsequent congenic strain targeting this QTL, however, could not confirm it. These conflicting results called into question
the validity of localization of a QTL by linkage followed by the use of a congenic strain made with an incomplete chromosome coverage. To resolve this issue, we constructed five new congenic strains, designated C17S.L1 to C17S.L5, that completely spanned the +/-2 LOD confidence interval supposedly containing the QTL. Each congenic strain was made by replacing a segment of the DSS rat by that of the normotensive Lewis (LEW) rat. The only section to be LL homozygous is the region on Chr 17 specified in a congenic strain, as evidenced by a total genome scan. The results showed that BPs of C17S.L1 and C17S.L2 were lower (P < 0.04) than that of DSS rats. In contrast, BPs of C17S.L3, C17S.L4, and C17S.L5 were not different (P > 0.6) from that of DSS rats. Consequently, a BP QTL must be located in an interval of approximately 15 cM shared between C17S.L1 and C17S.L2 and unique to them both, as opposed to C17S.L3, C17S.L4, and C17S.L5. The present study illustrates the importance of thorough chromosome coverage, the necessity for a genome-wide screening, and the use of "negative" controls in physically mapping a QTL by congenic strains.
Palijan A, etal., Hypertension 2003 Oct;42(4):515-22. Epub 2003 Aug 25
Chromosome mapping based on congenic strains can restrict quantitative trait loci (QTLs) for blood pressure (BP) into small intervals that are otherwise indistinguishable in linkage analysis. Also, congenic strains can be created to test a candidate gene to be a BP QTL. Taking full advantage of thes
e features, we produced 10 congenic strains by replacing various segments of chromosome (Chr) 10 of the Dahl salt-sensitive (DSS) rat with those of the Lewis (LEW) rat. These strains were made to systematically cover an entire section of Chr 10. Three of the strains were designed to narrow the intervals that harbor previously mapped QTL1 and QTL2. Two of the strains were designed for the express purpose of testing the QTL candidacy of loci for inducible nitric oxide synthase (Nos2) and angiotensin-converting enzyme (Ace) genes. BPs of these strains were measured by telemetry and compared with those of the DSS rat. Consequently, QTL1 and QTL2 were narrowed to segments of 53.5 and 100.4 centiRays, respectively. A new QTL, QTL3, was found between QTL1 and QTL2. Both Nos2 and Ace have been disqualified as QTLs in the DSS and LEW comparison. Therefore, there are no obvious candidate genes in the segments that harbor these 3 QTLs, which represent genes previously not thought to be involved in BP regulation. These QTLs will likely have an influence on studies of human hypertension because of their homology with the human CHR 17 region in which QTLs for BP have been found.
Moujahidine M, etal., Mamm Genome 2002 Mar;13(3):153-6.
A Chromosome (Chr) 16 segment of the Dahl salt-sensitive (S) rat was shown by linkage to contain a blood pressure (BP) quantitative trait locus (QTL). To verify and further narrow down the region harboring the QTL, we made two congenic strains by replacing two segments of the S rats with the homolog
ous segments of the Lewis (LEW) rats. The construction of these congenic strains was facilitated by a genome-wide marker screening. The two congenic strains contained a segment in common, and BPs of both were significantly lower than that of the S strain. Consequently, a BP QTL could be localized to the overlapping region of about 49.4 centiRay (cR) including the telomere on a radiation hybrid map. Heart weights, left and right ventricular weights, kidney weights, and aortic weights over length were all significantly decreased in the congenic strains compared with the S strain. Thus, there appeared to exist an association between the effects of the QTL on BP and on cardiac, renal, and vascular hypertrophy.
Vasakova M, etal., Scand J Immunol. 2007 Mar;65(3):265-70.
Idiopathic pulmonary fibrosis (IPF) is a serious disease characterized with progressive scarring of the lungs in which a genetic background is supposed. We have tested correlation of promotor regions of IL-1alpha and IL-4 gene polymorphisms with clinical parameters in IPF. We investigated the group
of 30 patients with IPF. The correlations of vital capacity (VC) and diffusing capacity for carbon monoxide (DL(CO)), bronchoalveolar lavage (BAL) fluid cell counts and high resolution computed tomography (HRCT) alveolar and interstitial scores with different genotypes of IL-4 at (-1098), (-590) and (-33) positions and IL-1 alpha at (-889) position were tested. The PCR method was used for genotyping. The carriers of CT genotype at IL-1 alpha (-889) position had higher VC at the time of diagnosis. The CC genotype at this position was more frequent in patients with higher counts of HLADR+ T lymphocytes in BAL. The GT genotype at IL-4 (-1098) position correlated with higher counts of CD4(+) T lymphocytes, and inversely the TT genotype with higher counts of CD8(+) T lymphocytes in BAL fluid. According to dynamic changes of HRCT score the CT genotype at IL-4 (-33) was more frequent in patients with progressive disease compared to that with stable disease. We assume from our data that the gene polymorphisms of the promotor region of IL-4 at position (-1098) and (-33) and IL-1 alpha at position (-889) are likely to play a pathogenic role in IPF and in modification of its clinical presentation and severity.
Vasakova M, etal., Respir Med. 2007 May;101(5):944-50. Epub 2006 Oct 23.
INTRODUCTION: Idiopathic pulmonary fibrosis (IPF) is a serious disease with unknown cause and the influence of cytokine gene polymorphisms is presumed in the etiology and pathogenesis of the disease. We used high-resolution computed tomography (HRCT) as a marker of disease stage and progression and
compared the alveolar and interstitial score with IL-1, IL-4, IL-12, IL-1RA and IL-4RA cytokine gene polymorphisms. SUBJECTS AND METHODS: The IPF patients were all Caucasians from the Czech Republic and consisted of 20 females and 10 males, with a mean age of 65 years, range 36-85. The HRCT results were evaluated by an experienced viewer using the interstitial and alveolar score scales, which were based on the IPF HRCT description system from Gay SE, Kazerooni EA, Tows GB, Lynch JP, Gross BH, Cascade PN, et al. [Idiopathic pulmonary fibrosis. Predicting response to therapy and survival. Am J Respir Crit Care Med 1998;157:1063-72]. We evaluated the polymorphisms of cytokine genes utilizing a PCR with sequence-specific primers method. RESULTS: The HRCT alveolar score was more pronounced in IL-4 RA (+1902) AG heterozygotes. The HRCT interstitial score was less severe in the IL-12 (-1188) AA homozygotes. According to progression of the HRCT interstitial score, the CC homozygosity at IL-1 RA (mspa 111100), the AA homozygosity at IL-4 RA (+1902) and CC homozygosity at IL-4(+33) positions were more frequent in patients with stable disease compared to those with progressive disease. CONCLUSIONS: We assume from our data that the polymorphisms of IL-4, IL-4RA, IL-1RA and IL-12 genes (genes of cytokines with regulatory activity) might influence the phenotype of IPF as shown by measurable changes in HRCT investigations.
Ariyarajah A, etal., J Hypertens 2004 Aug;22(8):1495-502.
OBJECTIVE: Our previous linkage analyses showed that there was likely a quantitative trait locus (QTL) for blood pressure (BP) on chromosome 8 (Chr 8) in the strain comparison between the Dahl salt-sensitive (S) and the Lewis (LEW) rats. The current work is to delineate the chromosome interval harbo
ring this QTL by using congenic strains with different chromosome substitutions. METHODS: Two congenic strains were produced by replacing different segments of the S rats with the homologous segments of the LEW rats. A genome-wide marker screening was utilized to accelerate this process. The two strains generated are designated as C8S.L1 and C8S.L2, respectively. BPs of the rats were measured by telemetry. RESULTS: C8S.L1 showed a BP lower than that of S rats. In contrast, C8S.L2 did not have chromosome overlaps with C8S.L1, but unexpectedly, exhibited a BP-raising effect, higher than that of S rats. CONCLUSION: There are at least two QTLs present in a section of Chr 8 that possess opposite BP effects. The current congenic work reveals not only the presence of QTLs, but the complexity of QTLs on BP. The novel congenic strain with hypertension more severe than S provides a new model for studies in elucidating physiological mechanisms controlling BP.
Alam SK, etal., Cell Death Differ. 2016 Apr;23(4):707-22. doi: 10.1038/cdd.2015.133. Epub 2015 Oct 23.
Mutation in the TP53 gene positively correlates with increased incidence of chemoresistance in different cancers. In this study, we investigated the mechanism of chemoresistance and epithelial-to-mesenchymal transition (EMT) in colorectal cancer involving the gain-of-function (GOF) mutant p53/ephrin
-B2 signaling axis. Bioinformatic analysis of the NCI-60 data set and subsequent hub prediction identified EFNB2 as a possible GOF mutant p53 target gene, responsible for chemoresistance. We show that the mutant p53-NF-Y complex transcriptionally upregulates EFNB2 expression in response to DNA damage. Moreover, the acetylated form of mutant p53 protein is recruited on the EFNB2 promoter and positively regulates its expression in conjunction with coactivator p300. In vitro cell line and in vivo nude mice data show that EFNB2 silencing restores chemosensitivity in mutant p53-harboring tumors. In addition, we observed high expression of EFNB2 in patients having neoadjuvant non-responder colorectal carcinoma compared with those having responder version of the disease. In the course of deciphering the drug resistance mechanism, we also show that ephrin-B2 reverse signaling induces ABCG2 expression after drug treatment that involves JNK-c-Jun signaling in mutant p53 cells. Moreover, 5-fluorouracil-induced ephrin-B2 reverse signaling promotes tumorigenesis through the Src-ERK pathway, and drives EMT via the Src-FAK pathway. We thus conclude that targeting ephrin-B2 might enhance the therapeutic potential of DNA-damaging chemotherapeutic agents in mutant p53-bearing human tumors.
Humphray SJ, etal., Nature. 2004 May 27;429(6990):369-74.
Chromosome 9 is highly structurally polymorphic. It contains the largest autosomal block of heterochromatin, which is heteromorphic in 6-8% of humans, whereas pericentric inversions occur in more than 1% of the population. The finished euchromatic sequence of chromosome 9 comprises 109,044,351 base
pairs and represents >99.6% of the region. Analysis of the sequence reveals many intra- and interchromosomal duplications, including segmental duplications adjacent to both the centromere and the large heterochromatic block. We have annotated 1,149 genes, including genes implicated in male-to-female sex reversal, cancer and neurodegenerative disease, and 426 pseudogenes. The chromosome contains the largest interferon gene cluster in the human genome. There is also a region of exceptionally high gene and G + C content including genes paralogous to those in the major histocompatibility complex. We have also detected recently duplicated genes that exhibit different rates of sequence divergence, presumably reflecting natural selection.
DNA methyltransferase 3A (DNMT3A) is an enzyme involved in DNA methylation that is frequently mutated in human hematologic malignancies. We have previously shown that inactivation of Dnmt3a in hematopoietic cells results in chronic lymphocytic leukemia in mice. Here we show that 12% of Dnmt3a-defici
ent mice develop CD8+ mature peripheral T cell lymphomas (PTCL) and 29% of mice are affected by both diseases. 10% of Dnmt3a+/- mice develop lymphomas, suggesting that Dnmt3a is a haploinsufficient tumor suppressor in PTCL. DNA methylation was deregulated genome-wide with 10-fold more hypo- than hypermethylated promoters and enhancers, demonstrating that hypomethylation is a major event in the development of PTCL. Hypomethylated promoters were enriched for binding sites of transcription factors AML1, NF-kappaB and OCT1, implying the transcription factors potential involvement in Dnmt3a-associated methylation. Whereas 71 hypomethylated genes showed an increased expression in PTCL, only 3 hypermethylated genes were silenced, suggesting that cancer-specific hypomethylation has broader effects on the transcriptome of cancer cells than hypermethylation. Interestingly, transcriptomes of Dnmt3a+/- and Dnmt3aDelta/Delta lymphomas were largely conserved and significantly overlapped with those of human tumors. Importantly, we observed downregulation of tumor suppressor p53 in Dnmt3a+/- and Dnmt3aDelta/Delta lymphomas as well as in pre-tumor thymocytes from 9 months old but not 6 weeks old Dnmt3a+/- tumor-free mice, suggesting that p53 downregulation is chronologically an intermediate event in tumorigenesis. Decrease in p53 is likely an important event in tumorigenesis because its overexpression inhibited proliferation in mouse PTCL cell lines, suggesting that low levels of p53 are important for tumor maintenance. Altogether, our data link the haploinsufficient tumor suppressor function of Dnmt3a in the prevention of mouse mature CD8+ PTCL indirectly to a bona fide tumor suppressor of T cell malignancies p53.
This is a pilot study to test the hypothesis that polymorphisms that may be linked to cyclooxygenase production may affect the likelihood and the nature of bleeding in patients with ulcer disease. Of the two polymorphism that have previously been studied for links we chose the A842G polymorphims. Of
the 50 patients with ulcer bleeding who were studied, 8 had a heterozygous polymorphisms and 42 had the normal configuration. On comparing these two groups. there were no significant differences in clinical presentation except that there was a tendency to have less gastric ulcers among those with the A842G/C50T polymorphism. Based on these studies we need to undertake a larger studies comparing these groups with those with ulcers without GI bleeding and those without ulcers
Yang L, etal., Oncotarget. 2015 Dec 22;6(41):43743-58. doi: 10.18632/oncotarget.6193.
CUB-domain-containing protein 1 (CDCP1) is a trans-membrane protein regulator of cell adhesion with a potent pro-migratory function in tumors. Given that proteolytic cleavage of the ectodomain correlates with outside-in oncogenic signaling, we characterized glycosylation in the context of cellular
processing and expression of CDCP1 in prostate cancer. We detected 135 kDa full-length and proteolytic processed 70 kDa species in a panel of PCa cell models. The relative expression of full-length CDCP1 correlated with the metastatic potential of syngeneic cell models and an increase in surface membrane expression of CDCP1 was observed in tumor compared to adjacent normal prostate tissues. We demonstrated that glycosylation of CDCP1 is a prerequisite for protein stability and plasma membrane localization, and that the expression level and extent of N-glycosylation of CDCP1 correlated with metastatic status. Interestingly, complex N-linked glycans with sialic acid chains were restricted to the N-terminal half of the ectodomain and absent in the truncated species. Characterization of the extracellular expression of CDCP1 identified novel circulating forms and revealed that extracellular vesicles provide additional processing pathways. Employing immunoaffinity mass spectrometry, we detected elevated levels of circulating CDCP1 in patient urine with high-risk disease. Our results establish that differential glycosylation, cell surface presentation and extracellular expression of CDCP1 are hallmarks of PCa progression.
Subramani E, etal., Fertil Steril. 2016 Apr;105(4):1076-1084.e5. doi: 10.1016/j.fertnstert.2015.12.015. Epub 2016 Jan 8.
OBJECTIVE: To investigate the influence of dormant Mycobacterium tuberculosis on the expression of various endometrial receptivity markers and leukemia inhibitory factor (LIF)-signal transducers and activators of transcription 3 (STAT3) signaling pathway. Expression of endometrial receptivity marke
rs and LIF-STAT3 signaling in in vitro decidualized human endometrial stromal cells (hESC) treated with 65 kDa mycobacterial heat shock protein (HSP65) is also explored. DESIGN: A prospective study. SETTING: Tertiary care hospital and reproductive health research unit. PATIENT(S): Endometrial tissue samples were collected from 38 women who tested positive for Mycobacterium tuberculosis and 30 normal women with proven fertility undergoing sterilization. In vitro decidualization of hESC was performed. INTERVENTION(S): Endometrial biopsies collected from all women during implantation window and treatment of hESC with HSP65. MAIN OUTCOME MEASURE(S): Measurement of various endometrial receptivity markers including alphavbeta3 integrin, E-cadherin, MECA-79, mucin-1, and pinopodes and LIF/LIFR-STAT3 signaling molecules expressed in the endometrium of women with dormant genital tuberculosis (GTB) during implantation window and measured also in HSP65-treated hESC. RESULT(S): Significantly reduced levels of endometrial receptivity markers LIF, LIFR, and pSTAT3 were observed in endometrium of women with dormant GTB as compared with controls. A similar trend was observed under in vitro conditions with decreased level of phosphorylated STAT3 in HSP65-treated hESC. However, no change in the expression of endometrial receptivity markers under in vitro conditions was observed. CONCLUSION(S): Our findings suggest that endometrium of women with dormant GTB is associated with poor receptivity, as evidenced by reduced receptivity markers and aberrant LIF-STAT3 signaling. In vitro treatment of hESC with HSP65 also confirms compromised endometrial decidualization.
Using the Illumina 450K array and a stringent statistical analysis with age and gender correction, we report genome-wide differences in DNA methylation between pathology-free regions derived from human multiple sclerosis-affected and control brains. Differences were subtle, but widespread and reprod
ucible in an independent validation cohort. The transcriptional consequences of differential DNA methylation were further defined by genome-wide RNA-sequencing analysis and validated in two independent cohorts. Genes regulating oligodendrocyte survival, such as BCL2L2 and NDRG1, were hypermethylated and expressed at lower levels in multiple sclerosis-affected brains than in controls, while genes related to proteolytic processing (for example, LGMN, CTSZ) were hypomethylated and expressed at higher levels. These results were not due to differences in cellular composition between multiple sclerosis and controls. Thus, epigenomic changes in genes affecting oligodendrocyte susceptibility to damage are detected in pathology-free areas of multiple sclerosis-affected brains.
Kaposi's sarcoma-associated herpesvirus (KSHV) enters human dermal microvascular endothelial cells (HMVEC-d), its naturalin vivotarget cells, by lipid raft-dependent macropinocytosis. The internalized viral envelope fuses with the macropinocytic membrane, and released capsid is transported to the n
uclear vicinity, resulting in the nuclear entry of viral DNA. The endosomal sorting complexes required for transport (ESCRT) proteins, which include ESCRT-0, -I, -II, and -III, play a central role in endosomal trafficking and sorting of internalized and ubiquitinated receptors. Here, we examined the role of ESCRT-0 component Hrs (hepatocyte growth factor-regulated tyrosine kinase substrate) in KSHV entry into HMVEC-d by macropinocytosis. Knockdown of Hrs by short hairpin RNA (shRNA) transduction resulted in significant decreases in KSHV entry and viral gene expression. Immunofluorescence analysis (IFA) and plasma membrane isolation and proximity ligation assay (PLA) demonstrated the translocation of Hrs from the cytosol to the plasma membrane of infected cells and association with alpha-actinin-4. In addition, infection induced the plasma membrane translocation and activation of the serine/threonine kinase ROCK1, a downstream target of the RhoA GTPase. Hrs knockdown reduced these associations, suggesting that the recruitment of ROCK1 is an Hrs-mediated event. Interaction between Hrs and ROCK1 is essential for the ROCK1-induced phosphorylation of NHE1 (Na(+)/H(+)exchanger 1), which is involved in the regulation of intracellular pH. Thus, our studies demonstrate the plasma membrane association of ESCRT protein Hrs during macropinocytosis and suggest that KSHV entry requires both Hrs- and ROCK1-dependent mechanisms and that ROCK1-mediated phosphorylation of NHE1 and pH change is an essential event required for the macropinocytosis of KSHV. IMPORTANCE: Macropinocytosis is the major entry pathway of KSHV in human dermal microvascular endothelial cells, the natural target cells of KSHV. Although the role of ESCRT protein Hrs has been extensively studied with respect to endosomal movement and sorting of ubiquitinated proteins into lysosomes, its function in macropinocytosis is not known. In the present study, we demonstrate for the first time that upon KSHV infection, the endogenous Hrs localizes to the plasma membrane and the membrane-associated Hrs facilitates assembly of signaling molecules, macropinocytosis, and virus entry. Hrs recruits ROCK1 to the membrane, which is required for the activation of NHE1 and an increase in submembranous intracellular pH occurring during macropinocytosis. These studies demonstrate that the localization of Hrs from the cytosol to the plasma membrane is important for coupling membrane dynamics to the cytosolic signaling events during macropinocytosis of KSHV.
Malonia SK, etal., Proc Natl Acad Sci U S A. 2015 Jul 14;112(28):8632-7. doi: 10.1073/pnas.1510929112. Epub 2015 Jun 29.
The tumor suppressor p53 plays a critical role in maintaining genomic stability. In response to genotoxic stress, p53 levels increase and induce cell-cycle arrest, senescence, or apoptosis, thereby preventing replication of damaged DNA. In unstressed cells, p53 is maintained at a low level. The ma
jor negative regulator of p53 is MDM2, an E3 ubiquitin ligase that directly interacts with p53 and promotes its polyubiquitination, leading to the subsequent destruction of p53 by the 26S proteasome. Following DNA damage, MDM2 is degraded rapidly, resulting in increased p53 stability. Because of the important role of MDM2 in modulating p53 function, it is critical to understand how MDM2 levels are regulated. Here we show that the F-box protein FBXO31, a candidate tumor suppressor encoded in 16q24.3 for which there is loss of heterozygosity in various solid tumors, is responsible for promoting MDM2 degradation. Following genotoxic stress, FBXO31 is phosphorylated by the DNA damage serine/threonine kinase ATM, resulting in increased levels of FBXO31. FBXO31 then interacts with and directs the degradation of MDM2, which is dependent on phosphorylation of MDM2 by ATM. FBXO31-mediated loss of MDM2 leads to elevated levels of p53, resulting in growth arrest. In cells depleted of FBXO31, MDM2 is not degraded and p53 levels do not increase following genotoxic stress. Thus, FBXO31 is essential for the classic robust increase in p53 levels following DNA damage.
Oligodendrocytes derive from progenitors (OPCs) through the interplay of epigenomic and transcriptional events. By integrating high-resolution methylomics, RNA-sequencing, and multiple transgenic lines, this study defines the role of DNMT1 in developmental myelination. We detected hypermethylation o
f genes related to cell cycle and neurogenesis during differentiation of OPCs, yet genetic ablation of Dnmt1 resulted in inefficient OPC expansion and severe hypomyelination associated with ataxia and tremors in mice. This phenotype was not caused by lineage switch or massive apoptosis but was characterized by a profound defect of differentiation associated with changes in exon-skipping and intron-retention splicing events and by the activation of an endoplasmic reticulum stress response. Therefore, loss of Dnmt1 in OPCs is not sufficient to induce a lineage switch but acts as an important determinant of the coordination between RNA splicing and protein synthesis necessary for myelin formation.
Auer DR, etal., Biotechnol Lett. 2014 Jun;36(6):1179-85. doi: 10.1007/s10529-014-1473-x. Epub 2014 Feb 22.
Polymorphic non-coding variants at the NOS1AP locus have been associated with the common cardiac, metabolic and neurological traits and diseases. Although, in vitro gene targeting-based cellular and biochemical studies have shed some light on NOS1AP function in cardiac and neuronal tissue, to enhan
ce our understanding of NOS1AP function in mammalian physiology and disease, we report the generation of cre recombinase-conditional Nos1ap over-expression transgenic mice (Nos1ap (Tg)). Conditional transgenic mice were generated by the pronuclear injection method and three independent, single-site, multiple copies integration event-based founder lines were selected. For heart-restricted over-expression, Nos1ap (Tg) mice were crossed with Mlc2v-cre and Nos1ap transcript over-expression was observed in left ventricles from Nos1ap (Tg); Mlc2v-cre F1 mice. We believe that with the potential of conditional over-expression, Nos1ap (Tg) mice will be a useful resource in studying NOS1AP function in various tissues under physiological and disease states.
The contribution of the microenvironment to pancreatic acinar-to-ductal metaplasia (ADM), a preneoplastic transition in oncogenic Kras-driven pancreatic cancer progression, is currently unclear. Here we show that disruption of paracrine Hedgehog signaling via genetic ablation of Smoothened (Smo) in
stromal fibroblasts in a Kras(G12D) mouse model increased ADM. Smo-deleted fibroblasts had higher expression of transforming growth factor-alpha (Tgfa) mRNA and secreted higher levels of TGFalpha, leading to activation of EGFR signaling in acinar cells and increased ADM. The mechanism involved activation of AKT and noncanonical activation of the GLI family transcription factor GLI2. GLI2 was phosphorylated at Ser230 in an AKT-dependent fashion and directly regulated Tgfa expression in fibroblasts lacking Smo Additionally, Smo-deleted fibroblasts stimulated the growth of Kras(G12D)/Tp53(R172H) pancreatic tumor cells in vivo and in vitro. These results define a non-cell-autonomous mechanism modulating Kras(G12D)-driven ADM that is balanced by cross-talk between Hedgehog/SMO and AKT/GLI2 pathways in stromal fibroblasts.
Wilson disease (WD) is caused by defects in ATP7B gene due to impairment of normal function of the copper transporting P-type ATPase. This study describes a comprehensive genetic analysis of 199 Indian WD patients including mutations detected in our previous studies, undertakes functional assessmen
t of the nucleotide variants in ATP7B promoter and correlates genotype with disease phenotype. The patient cohort harbors a total of 10 common and 48 rare mutations in the coding region of ATP7B including 21 novel changes. The common mutations represent 74% of characterized coding mutant alleles with p.C271X (63/260) and p.G1101R (7/31) being the most prevalent in eastern and western Indian patients, respectively. The mutation spectrum between east and west is mostly different with only three mutations (p.G1061E, p.N1270S and p.A1049A-fs) being shared between both the groups. Eight novel and 10 reported variants have been detected in the promoter and non-coding regions (5' and 3'UTRs) of ATP7B. Promoter reporter assay demonstrated that 3 novel variants and 5 reported polymorphisms alter the gene expression to a considerable extent; hence might play important role in ATP7B gene regulation. We devised the neurological involvement score to capture the spectrum of neurological involvement in WD patients. By utilizing the age at onset, neurological involvement score and ATP7B mutation background, we generated a genotype-phenotype matrix that could be effectively used to depict the phenotypic spectra of WD affected individuals and serve as a platform to identify prospective "outliers" to be investigated for their remarkable phenotypic divergence.
Non-syndromic pituitary gigantism can result from AIP mutations or the recently identified Xq26.3 microduplication causing X-linked acrogigantism (XLAG). Within Xq26.3, GPR101 is believed to be the causative gene, and the c.924G > C (p.E308D) variant in this orphan G protein-coupled receptor has bee
n suggested to play a role in the pathogenesis of acromegaly.We studied 153 patients (58 females and 95 males) with pituitary gigantism. AIP mutation-negative cases were screened for GPR101 duplication through copy number variation droplet digital PCR and high-density aCGH. The genetic, clinical and histopathological features of XLAG patients were studied in detail. 395 peripheral blood and 193 pituitary tumor DNA samples from acromegaly patients were tested for GPR101 variants.We identified 12 patients (10 females and 2 males; 7.8 %) with XLAG. In one subject, the duplicated region only contained GPR101, but not the other three genes in found to be duplicated in the previously reported patients, defining a new smallest region of overlap of duplications. While females presented with germline mutations, the two male patients harbored the mutation in a mosaic state. Nine patients had pituitary adenomas, while three had hyperplasia. The comparison of the features of XLAG, AIP-positive and GPR101&AIP-negative patients revealed significant differences in sex distribution, age at onset, height, prolactin co-secretion and histological features. The pathological features of XLAG-related adenomas were remarkably similar. These tumors had a sinusoidal and lobular architecture. Sparsely and densely granulated somatotrophs were admixed with lactotrophs; follicle-like structures and calcifications were commonly observed. Patients with sporadic of familial acromegaly did not have an increased prevalence of the c.924G > C (p.E308D) GPR101 variant compared to public databases.In conclusion, XLAG can result from germline or somatic duplication of GPR101. Duplication of GPR101 alone is sufficient for the development of XLAG, implicating it as the causative gene within the Xq26.3 region. The pathological features of XLAG-associated pituitary adenomas are typical and, together with the clinical phenotype, should prompt genetic testing.
The IL-1beta and type I interferon-beta (IFN-beta) molecules are important inflammatory cytokines elicited by the eukaryotic host as innate immune responses against invading pathogens and danger signals. Recently, a predominantly nuclear gamma-interferon-inducible protein 16 (IFI16) involved in tra
nscriptional regulation has emerged as an innate DNA sensor which induced IL-1beta and IFN-beta production through inflammasome and STING activation, respectively. Herpesvirus (KSHV, EBV, and HSV-1) episomal dsDNA genome recognition by IFI16 leads to IFI16-ASC-procaspase-1 inflammasome association, cytoplasmic translocation and IL-1beta production. Independent of ASC, HSV-1 genome recognition results in IFI16 interaction with STING in the cytoplasm to induce interferon-beta production. However, the mechanisms of IFI16-inflammasome formation, cytoplasmic redistribution and STING activation are not known. Our studies here demonstrate that recognition of herpesvirus genomes in the nucleus by IFI16 leads into its interaction with histone acetyltransferase p300 and IFI16 acetylation resulting in IFI16-ASC interaction, inflammasome assembly, increased interaction with Ran-GTPase, cytoplasmic redistribution, caspase-1 activation, IL-1beta production, and interaction with STING which results in IRF-3 phosphorylation, nuclear pIRF-3 localization and interferon-beta production. ASC and STING knockdowns did not affect IFI16 acetylation indicating that this modification is upstream of inflammasome-assembly and STING-activation. Vaccinia virus replicating in the cytoplasm did not induce nuclear IFI16 acetylation and cytoplasmic translocation. IFI16 physically associates with KSHV and HSV-1 genomes as revealed by proximity ligation microscopy and chromatin-immunoprecipitation studies which is not hampered by the inhibition of acetylation, thus suggesting that acetylation of IFI16 is not required for its innate sensing of nuclear viral genomes. Collectively, these studies identify the increased nuclear acetylation of IFI16 as a dynamic essential post-genome recognition event in the nucleus that is common to the IFI16-mediated innate responses of inflammasome induction and IFN-beta production during herpesvirus (KSHV, EBV, HSV-1) infections.
Ray K, etal., Neurochem Int. 2011 Jan;58(1):112-8. Epub 2010 Nov 12.
Sojourners to high altitude experience poor-quality of sleep due to hypobaric hypoxia (HH). Brain neurotransmitters are the key regulators of sleep wakefulness. Scientific literature has limited information on the role of brain neurotransmitters involved in sleep disturbance in HH. The present study
aimed to investigate the time dependent changes in neurotransmitter levels and enzymes involved in the biosynthesis of brain neurotransmitters in frontal cortex, brain stem, cerebellum, pons and medulla and the effect of these alterations on sleep architecture in HH. Thirty adult Sprague-Dawley rats, body weight of 230-250 g were exposed to simulated altitude approximately 7620 m, 282 mm Hg, partial pressure of O(2) 59 mm Hg for 7 and 14 days continuously in an animal decompression chamber. After 7 and 14 days of HH, brain nor-epinephrine and dopamine levels were significantly increased in frontal cortex, brain stem, cerebellum and pons and medulla whereas serotonin level was significantly reduced in frontal cortex and pons and medulla after 14 days of HH. Tyrosine hydroxylase level in locus coeruleus (LC) was significantly increased whereas Choline Acetyl Transferase and Glutamic Acid Decarboxylase (GAD) levels were significantly reduced in laterodorsal-tegmentum and pedunculopontine-tegmentum after 7 days of HH. GAD was also reduced in LC after 7 days HH. Alteration in these neurotransmitters and enzyme levels was accompanied with reduction in quality and quantity of sleep. There was a significant increase in sleep latency, rapid eye movement (REM) latency, duration of active awake, quiet awake, quiet sleep and a significant decrease in duration of REM sleep and deep sleep on day 7 and 14 of HH. It was concluded that HH alters the expression of enzymes linked to sleep neurotransmitter synthesis pathway and subsequent loss of homeostasis at neurotransmitter level disrupts the sleep pattern in hypobaric hypoxia.
Sulfotransferase catalyzed sulfation is important in the regulation of different hormones and the metabolism of hydroxyl containing xenobiotics. In the present investigation, we examined the effects of hyperoxia on aryl sulfotransferase IV in rat lungs in vivo. The enzyme activity of aryl sulfotrans
ferase IV increased 3- to 8-fold in >95% O2 treated rat lungs. However, hyperoxic exposure did not change the mRNA and protein levels of aryl sulfotransferase IV in lungs as revealed by Western blot and RT-PCR. This suggests that oxidative regulation occurs at the level of protein modification. The increase of nonprotein soluble thiol and reduced glutathione (GSH)/oxidized glutathione (GSSG) ratios in treated lung cytosols correlated well with the aryl sulfotransferase IV activity increase. In vitro, rat liver cytosol 2-naphthol sulfation activity was activated by GSH and inactivated by GSSG. Our results suggest that Cys residue chemical modification is responsible for the in vivo and in vitro oxidative regulation. The molecular modeling structure of aryl sulfotransferase IV supports this conclusion. Our gel filtration chromatography results demonstrated that neither GSH nor GSSG treatment changed the existing aryl sulfotransferase IV dimer status in cytosol, suggesting that oxidative regulation of aryl sulfotransferase IV is not caused by dimer-monomer status change.
TAR DNA-binding protein 43 (TDP-43) is a major component in aggregates of ubiquitinated proteins in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Here we report that lipopolysaccharide (LPS)-induced inflammation can promote TDP-43 mislocalization and aggregation.
In culture, microglia and astrocytes exhibited TDP-43 mislocalization after exposure to LPS. Likewise, treatment of the motoneuron-like NSC-34 cells with TNF-alpha (TNF-alpha) increased the cytoplasmic levels of TDP-43. In addition, the chronic intraperitoneal injection of LPS at a dose of 1mg/kg in TDP-43(A315T) transgenic mice exacerbated the pathological TDP-43 accumulation in the cytoplasm of spinal motor neurons and it enhanced the levels of TDP-43 aggregation. These results suggest that inflammation may contribute to development or exacerbation of TDP-43 proteinopathies in neurodegenerative disorders.
Cordeiro CA, etal., Invest Ophthalmol Vis Sci. 2008 May;49(5):1979-82. doi: 10.1167/iovs.07-1393.
PURPOSE: Experimental data have demonstrated a relevant role for IL-10, an anti-inflammatory cytokine, in the modulation of acute ocular toxoplasmosis. Therefore, this study was conducted to investigate the possible association between an IL10 gene polymorphism at position -1082 and toxoplasmic reti
nochoroiditis (TR) in humans. METHODS: One hundred patients with diagnosed TR were recruited from the Uveitis Section, Federal University of Minas Gerais. For comparison, one hundred healthy blood donors with positive serology for toxoplasmosis and without retinal signs of previous TR were included in the study. Genomic DNA was obtained from oral swabs of individuals and amplified using polymerase chain reaction (PCR) with specific primers flanking the locus -1082 of IL10 (-1082G/A). PCR products were subjected to restriction endonuclease digestion and analyzed by polyacrylamide gel electrophoresis, to distinguish allele G and A of the IL-10 gene, allowing the detection of the polymorphism and determination of genotypes. RESULTS: There was a significant difference in the genotype distribution between TR patients and control subjects (chi(2) = 6.33, P = 0.04). Carriers of the IL10 -1082 A allele (AA+AG genotypes) were more often patients with TR than control subjects (chi(2) = 5.97, P = 0.01, OR, 2.55; 95% CI, 1.11 < OR < 5.55). In a subgroup analysis, there was no significant difference in genotypes and allele carriage regarding visual acuity, involvement of both eyes and TR recurrence. CONCLUSIONS: This study suggests that the genotypes related with a low production of IL-10 may be associated with the occurrence of TR.
Interleukin (IL)-6 is an inflammatory mediator involved in bone resorption. G/C polymorphism at position -174 of the IL-6 gene has been reported to influence IL-6 expression, with the G allele associated with higher expression levels. The aims of this study were to investigate the expression of IL-6
as well as the incidence of IL-6 (-174) gene polymorphism and their correlation to the severity of periodontitis in Brazilians. Peripheral blood mononuclear cells were collected from 12 non-smoker individuals with periodontitis for evaluation of IL-6 expression using flow cytometry. We observed a positive correlation between the mean clinical attachment loss and intensity of expression of IL-6, in which the greater the attachment loss, the higher the expression of IL-6 (P=0 x 007, R2=0 x 52). Also, patients with severe periodontitis displayed a higher intensity of IL-6 expression compared to moderate periodontitis (P=0 x 04). To determine the occurrence of IL-6 gene polymorphism, DNA was obtained from oral swabs of 209 Brazilian individuals with and without periodontitis. Polymerase chain reaction, restriction endonuclease digestion and electrophoresis were performed, allowing for detection of the IL-6 (-174) polymorphism. We observed that non-smokers with moderate periodontitis (P=0 x 05) and control (P=0 x 04) groups displayed a higher incidence of the G genotype when compared to severe periodontitis. This suggests that the G genotype may represent a protective role in severity of periodontitis. Thus, the increased expression of IL-6 and IL-6 (-174) polymorphism are associated with periodontal disease severity in Brazilian individuals.
Cordeiro CA, etal., Acta Ophthalmol. 2013 Jun;91(4):e311-4. doi: 10.1111/aos.12046. Epub 2013 Jan 22.
PURPOSE: Experimental data have demonstrated a relevant role for IL-6 in the modulation of acute ocular toxoplasmosis. Therefore, we aim to investigate the possible association between the IL-6 gene polymorphism at position -174 and toxoplasmic retinochoroiditis (TR) in humans. METHODS: Ninety-seven
patients with diagnosed TR were recruited from the Uveitis Section, Federal University of Minas Gerais. For comparison, 83 healthy blood donors with positive serology for toxoplasmosis and without retinal signs of previous TR were included in the study. Genomic DNA was obtained from oral swabs of individuals and amplified using polymerase chain reaction (PCR) with specific primers flanking the locus -174 of IL-6 (-174G/C). PCR products were submitted to restriction endonuclease digestion and analysed by polyacrylamide gel electrophoresis to distinguish allele G and C of the IL-6 gene, allowing the detection of the polymorphism and determination of genotypes. RESULTS: There was a significant difference in the genotype (chi(2) = 12.9, p = 0.001) and allele (chi(2) = 6.62, p = 0.01) distribution between TR patients and control subjects. In a subgroup analysis, there was no significant difference in genotypes and allele frequencies regarding TR recurrence. CONCLUSIONS: This study suggests that the genotypes related with a lower production of IL-6 may be associated with the occurrence of TR.
Pathophysiological functions of cardiac cystic fibrosis transmembrane conductance regulator (cCFTR) in ischemia are not well known. Using neonatal rat ventricular cardiomyocytes in primary culture in this study, we thus examined whether the CFTR protein is expressed and is functioning as a cAMP-acti
vated anion channel on the plasma membrane under ischemic conditions. After the cells were subjected to simulated ischemia (O(2) and glucose deprivation), an up-regulation of the CFTR expression was transiently observed in the membrane fraction by Western blot. A peak expression of mature CFTR protein was found at 3 h of ischemia, and thereafter the signal diminished gradually. In contrast, the results of Northern blot indicated that the expression level of CFTR mRNA changed little until 3 h of ischemia, whereas the level slightly decreased after 8 h of ischemia. An immunohistochemical examination showed, in agreement with the results of Western blot analysis, that the expression of CFTR protein on the plasma membrane became most prominent at 3 h of ischemia, whereas the plasmalemmal CFTR signal was markedly reduced after 8 h of ischemia. Whole-cell recordings showed that the cardiomyocytes responded to cAMP with an activation of time- and voltage-independent currents that contained an anion-selective component sensitive to CFTR Cl(-) channel blockers (NPPB and glibenclamide) but not to a stilbene-derivative conventional Cl(-) channel blocker (SITS). This cAMP-activated Cl(-) channel current was found to be enhanced after an application of ischemic stress for 3 to 4 h. These findings indicate that a plasmalemmal expression of CFTR is transiently enhanced under glucose-free hypoxic conditions presumably because of a posttranslational control.
Familial Mediterranean fever (FMF) is a recessive disorder characterized by episodes of fever with serositis or synovitis. Recently the FMF gene (MEFV) was cloned; the protein product, pyrin/marenostrin, is thought to regulate inflammation in myeloid cells. In this manuscript we report the mouse and
rat homologs of MEFV. The murine gene contains ten exons with a coding sequence of 2304 bp, while the rat homolog has nine exons with a coding sequence of 2253 bp. A considerable amino acid sequence homology was observed between the mouse and human (47.6% identity and 65.5% similarity) and between the mouse and rat genes (73.5% identity and 82.1% similarity). The predicted rodent proteins have several important domains and signals found in human pyrin, including a B-box zinc finger domain, Robbins-Dingwall nuclear localization signal, and coiled-coil domain. However, perhaps because of an ancient frame-shift mutation, neither the mouse nor the rat protein has an intact C-terminal B30.2 domain, in which most FMF-associated mutations have been found in human MEFV. Nevertheless, like the human gene, mouse Mefv is expressed in peripheral blood granulocytes but not lymphocytes. Consistent with its expression in granulocytes, Mefv was detected at high levels in the primary follicles and marginal zones of the splenic white pulp. Mefv is localized on mouse Chromosome (Chr) 16, region A3-B1, extending a region of synteny with human Chr 16p13.3. Development of knockout and knockin mouse models may provide further insights into the functional evolution of this gene.
Pathak A, etal., Hum Genet. 2015 Jul;134(7):775-87. doi: 10.1007/s00439-015-1550-9. Epub 2015 May 5.
Juvenile myelomonocytic leukemia (JMML) is a pediatric myeloproliferative neoplasm that arises from malignant transformation of the stem cell compartment and results in increased production of myeloid cells. Somatic and germline variants in CBL (Casitas B-lineage lymphoma proto-oncogene) have been a
ssociated with JMML. We report an incompletely penetrant CBL Y371C mutation discovered by whole-exome sequencing in three individuals with JMML in a large pedigree with 35 years of follow-up. The Y371 residue is highly evolutionarily conserved among CBL orthologs and paralogs. In silico bioinformatics prediction programs suggested that the Y371C mutation is highly deleterious. Protein structural modeling revealed that the Y371C mutation abrogated the ability of the CBL protein to adopt a conformation that is required for ubiquitination. Clinically, the three mutation-positive JMML individuals exhibited variable clinical courses; in two out of three, primary hematologic abnormalities persisted into adulthood with minimal clinical symptoms. The penetrance of the CBL Y371C mutation was 30% for JMML and 40% for all leukemia. Of the 8 mutation carriers in the family with available photographs, only one had significant dysmorphic features; we found no evidence of a clinical phenotype consistent with a "CBL syndrome". Although CBL Y371C has been previously reported in familial JMML, we are the first group to follow a complete pedigree harboring this mutation for an extended period, revealing additional information about this variant's penetrance, function and natural history.
Perilipin 5 (PLIN5) is a lipid droplet (LD) protein highly expressed in oxidative tissues, including the fasted liver. However, its expression also increases in nonalcoholic fatty liver. To determine whether PLIN5 regulates metabolic phenotypes of hepatosteatosis under nutritional excess, liver targ
eted overexpression of PLIN5 was achieved using adenoviral vector (Ad-PLIN5) in male C57BL/6J mice fed high-fat diet. Mice treated with adenovirus expressing green fluorescent protein (GFP) (Ad-GFP) served as control. Ad-PLIN5 livers increased LD in the liver section, and liquid chromatography with tandem mass spectrometry revealed increases in lipid classes associated with LD, including triacylglycerol, cholesterol ester, and phospholipid classes, compared with Ad-GFP liver. Lipids commonly associated with hepatic lipotoxicity, diacylglycerol, and ceramides, were also increased in Ad-PLIN5 liver. The expression of genes in lipid metabolism regulated by peroxisome proliferator-activated receptor-alpha was reduced suggestive of slower mobilization of stored lipids in Ad-PLIN5 mice. However, the increase of hepatosteatosis by PLIN5 overexpression did not worsen glucose homeostasis. Rather, serum insulin levels were decreased, indicating better insulin sensitivity in Ad-PLIN5 mice. Moreover, genes associated with liver injury were unaltered in Ad-PLIN5 steatotic liver compared with Ad-GFP control. Phosphorylation of protein kinase B was increased in Ad-PLIN5-transduced AML12 hepatocyte despite of the promotion of fatty acid incorporation to triacylglycerol as well. Collectively, our data indicates that the increase in liver PLIN5 during hepatosteatosis drives further lipid accumulation but does not adversely affect hepatic health or insulin sensitivity.
Zhao J, etal., Circ Res. 2020 Aug 14;127(5):677-692. doi: 10.1161/CIRCRESAHA.119.316398. Epub 2020 Jun 4.
RATIONALE: Unproven theories abound regarding the long-range uptake and endocrine activity of extracellular blood-borne microRNAs into tissue. In pulmonary hypertension (PH), microRNA-210 (miR-210) in pulmonary endothelial cells promotes disease, but its activity as an extracellular molec
ule is incompletely defined. OBJECTIVE: We investigated whether chronic and endogenous endocrine delivery of extracellular miR-210 to pulmonary vascular endothelial cells promotes PH. METHODS AND RESULTS: Using miR-210 replete (wild-type [WT]) and knockout mice, we tracked blood-borne miR-210 using bone marrow transplantation and parabiosis (conjoining of circulatory systems). With bone marrow transplantation, circulating miR-210 was derived predominantly from bone marrow. Via parabiosis during chronic hypoxia to induce miR-210 production and PH, miR-210 was undetectable in knockout-knockout mice pairs. However, in plasma and lung endothelium, but not smooth muscle or adventitia, miR-210 was observed in knockout mice of WT-knockout pairs. This was accompanied by downregulation of miR-210 targets ISCU (iron-sulfur assembly proteins)1/2 and COX10 (cytochrome c oxidase assembly protein-10), indicating endothelial import of functional miR-210. Via hemodynamic and histological indices, knockout-knockout pairs were protected from PH, whereas knockout mice in WT-knockout pairs developed PH. In particular, pulmonary vascular engraftment of miR-210-positive interstitial lung macrophages was observed in knockout mice of WT-knockout pairs. To address whether engrafted miR-210-positive myeloid or lymphoid cells contribute to paracrine miR-210 delivery, we studied miR-210 knockout mice parabiosed with miR-210 WT; Cx3cr1 knockout mice (deficient in myeloid recruitment) or miR-210 WT; Rag1 knockout mice (deficient in lymphocytes). In both pairs, miR-210 knockout mice still displayed miR-210 delivery and PH, thus demonstrating a pathogenic endocrine delivery of extracellular miR-210. CONCLUSIONS: Endogenous blood-borne transport of miR-210 into pulmonary vascular endothelial cells promotes PH, offering fundamental insight into the systemic physiology of microRNA activity. These results also describe a platform for RNA-mediated crosstalk in PH, providing an impetus for developing blood-based miR-210 technologies for diagnosis and therapy in this disease.
Karlsson E, etal., Breast Cancer Res Treat. 2015 Aug;153(1):31-40. doi: 10.1007/s10549-015-3516-y. Epub 2015 Jul 25.
Breast cancer is a heterogeneous disease and new clinical markers are needed to individualise disease management and therapy further. Alterations in the PI3K/AKT pathway, mainly PIK3CA mutations, have been shown frequently especially in the luminal breast cancer subtypes, suggesting a cross-talk bet
ween ER and PI3K/AKT. Aberrant PI3K/AKT signalling has been connected to poor response to anti-oestrogen therapies. In vitro studies have shown protein tyrosine phosphatase, non-receptor type 2 (PTPN2) as a previously unknown negative regulator of the PI3K/AKT pathway. Here, we evaluate possible genomic alterations in the PTPN2 gene and its potential as a new prognostic and treatment predictive marker for endocrine therapy benefit in breast cancer. PTPN2 gene copy number was assessed by real-time PCR in 215 tumour samples from a treatment randomised study consisting of postmenopausal patients diagnosed with stage II breast cancer 1976-1990. Corresponding mRNA expression levels of PTPN2 were evaluated in 86 available samples by the same methodology. Gene copy loss of PTPN2 was detected in 16% (34/215) of the tumours and this was significantly correlated with lower levels of PTPN2 mRNA. PTPN2 gene loss and lower mRNA levels were associated with activation of AKT and a poor prognosis. Furthermore, PTPN2 gene loss was a significant predictive marker of poor benefit from tamoxifen treatment. In conclusion, genomic loss of PTPN2 may be a previously unknown mechanism of PI3K/AKT upregulation in breast cancer. PTPN2 status is a potential new clinical marker of endocrine treatment benefit which could guide further individualised therapies in breast cancer.
Star fishes (Asteroidea) are rich in polar steroids with diverse structural characteristics. The structural modifications of star fish steroids occur at 3beta, 4beta, 5alpha, 6alpha (or beta), 7alpha (or beta), 8, 15alpha (or beta) and 16beta positions of the steroidal nucleus and in the side chain.
Widely found polar steroids in starfishes include polyhydroxysteroids, steroidal sulfates, glycosides, steroid oligoglycosides etc. Bioactivity of these steroids is less studied; only a few reports like antibacterial, cytotoxic activity etc. are available. In continuation of our search for bioactive molecules from natural sources, we undertook in silico screening of steroids from star fishes against Bcl-2 and CDK-4/Cyclin D1 - two important targets of progression and proliferation of cancer cells. We have screened 182 natural steroids from star fishes occurring in different parts of the world and their 282 soft-derivatives by in silico methods. Their physico-chemical properties, drug-likeliness, binding potential with the selected targets, ADMET (absorption, distribution, metabolism, toxicity) were predicted. Further, the results were compared with those of existing steroidal and non steroidal drugs and inhibitors of Bcl-2 and CDK-4/Cyclin D1. The results are promising and unveil that some of these steroids can be potent leads for cancer treatments.
Our objective was to investigate the mitochondrial dynamics following oxygen-glucose deprivation (OGD) in cultured rat cortical neurons. We documented changes in morphology, protein expression, and DNA levels in mitochondria following OGD and examined the roles of mitochondrial fission [dynamin-rela
ted protein 1 (Drp1), fission protein-1 (Fis1)] and fusion [mitofusin-1 (Mfn1), mitofusin-2 (Mfn2), and optic atrophy-1 protein (OPA1)] proteins on mitochondrial biogenesis and morphogenesis. We tested the effects of two Drp1 blockers [15-deoxy-¿12,14-Prostaglandin J2 (PGJ2) and Mitochondrial Division Inhibitor (Mdivi-1)] on mitochondrial dynamics and cell survival. One hour of OGD had minimal effects on neuronal viability but mitochondria appeared condensed. Three hours of OGD caused a 60% decrease in neuronal viability accompanied by a transition from primarily normal/tubular and lesser number of rounded mitochondria during normoxia to either poorly labeled or small and large rounded mitochondria. The percentage of rounded mitochondria remained the same. The mitochondrial voltage-dependent anion channel, Complex V, and mitoDNA levels increased after OGD associated with a dramatic reduction in Drp1 expression, less reduction in Mfn2 expression, an increase in Mfn1 expression, with no changes in either OPA1 or Fis1. Although PGJ2 increased polymerization of Drp1, it did not reduce cell death or alter mitochondrial morphology following OGD and Mdivi-1 did not protect neurons against OGD. In summary, mitochondrial biogenesis and maintained fusion occurred in neurons along with mitochondrial fission following OGD; thus Mfn1 but not Drp1 may be a major regulator of these processes.
Rohatgi S, etal., J Immunol. 2009 May 1;182(9):5570-85. doi: 10.4049/jimmunol.0803254.
Immunization of human volunteers with a single dose of pneumococcal surface protein A (PspA) stimulates broad cross-reactive Abs to heterologous PspA molecules that, when transferred, protect mice from fatal infection with Streptococcus pneumoniae. In this study, we report the molecular characteriza
tion of 36 mouse mAbs generated against the extracellular domain of PspA (PspA(3-286)) from strain R36A. Abs to PspA(3-286) were encoded by diverse V(H) and V(kappa) families/genes. The H chain CDR3 and L chain CDR3 lengths were 3-13 (7.8 +/- 0.5) and 8-9 (8.7 +/- 0.2) codons, respectively. Unexpectedly, seven hybridomas expressed H chains that lack D(H) gene-derived amino acids. Nontemplate-encoded addition(s) were observed in the H chain expressed in six of these seven hybridomas; Palindromic addition(s) were absent. Absence of D(H) gene-derived amino acids did not prevent anti-PspA(3-286) mAbs from attaining average relative avidity. Avidity maturation occurred during primary IgG anti-PspA(3-286) polyclonal Ab response in PspA(3-286)- and R36A-immunized mice. Compared with PspA(3-286)-immunized mice, the relative avidity of the primary polyclonal IgG Abs was higher in R36A immunized mice on days 72, 86, and 100. Two pairs of clonally related hybridomas were observed. D(H) genes expressed in the majority (75.9%) of the hybridomas used reading frame 3. Analysis of replacement/silent mutation ratio in the CDR and framework regions provided evidence for Ag-driven selection in 11 mAbs. Based on epitope localization experiments, the mAbs were classified into 12 independent groups. ELISA additivity assay indicated that members within a group recognized topographically related epitopes. This study provides molecular insights into the biology of D(H)-less Abs.
Polymeropoulos MH, etal., Science. 1997 Jun 27;276(5321):2045-7.
Parkinson's disease (PD) is a common neurodegenerative disorder with a lifetime incidence of approximately 2 percent. A pattern of familial aggregation has been documented for the disorder, and it was recently reported that a PD susceptibility gene in a large Italian kindred is located on the long
arm of human chromosome 4. A mutation was identified in the alpha-synuclein gene, which codes for a presynaptic protein thought to be involved in neuronal plasticity, in the Italian kindred and in three unrelated families of Greek origin with autosomal dominant inheritance for the PD phenotype. This finding of a specific molecular alteration associated with PD will facilitate the detailed understanding of the pathophysiology of the disorder.
Kruer MC, etal., Ann Neurol. 2013 Dec;74(6):805-14. doi: 10.1002/ana.23971.
OBJECTIVE: Cerebral palsy is estimated to affect nearly 1 in 500 children, and although prenatal and perinatal contributors have been well characterized, at least 20% of cases are believed to be inherited. Previous studies have identified mutations in the actin-capping protein KANK1 and the adaptor
protein-4 complex in forms of inherited cerebral palsy, suggesting a role for components of the dynamic cytoskeleton in the genesis of the disease. METHODS: We studied a multiplex consanguineous Jordanian family by homozygosity mapping and exome sequencing, then used patient-derived fibroblasts to examine functional consequences of the mutation we identified in vitro. We subsequently studied the effects of adducin loss of function in Drosophila. RESULTS: We identified a homozygous c.1100G>A (p.G367D) mutation in ADD3, encoding gamma adducin in all affected members of the index family. Follow-up experiments in patient fibroblasts found that the p.G367D mutation, which occurs within the putative oligomerization critical region, impairs the ability of gamma adducin to associate with the alpha subunit. This mutation impairs the normal actin-capping function of adducin, leading to both abnormal proliferation and migration in cultured patient fibroblasts. Loss of function studies of the Drosophila adducin ortholog hts confirmed a critical role for adducin in locomotion. INTERPRETATION: Although likely a rare cause of cerebral palsy, our findings indicate a critical role for adducins in regulating the activity of the actin cytoskeleton, suggesting that impaired adducin function may lead to neuromotor impairment and further implicating abnormalities of the dynamic cytoskeleton as a pathogenic mechanism contributing to cerebral palsy.
Sun L, etal., J Biol Chem. 2016 Mar 11;291(11):5688-707. doi: 10.1074/jbc.M115.669952. Epub 2016 Jan 20.
Diabetic nephropathy (DN) is characterized by perturbations in metabolic/cellular signaling pathways with generation of reactive oxygen species (ROS). The ROS are regarded as a common denominator of various pathways, and they inflict injury on renal glomerular cells. Recent studies indicate that t
ubular pathobiology also plays a role in the progression of DN. However, the mechanism(s) for how high (25 mm) glucose (HG) ambience induces tubular damage remains enigmatic. myo-Inositol oxygenase (MIOX) is a tubular enzyme that catabolizes myo-inositol to d-glucuronate via the glucuronate-xylulose (G-X) pathway. In this study, we demonstrated that G-X pathway enzymes are expressed in the kidney, and MIOX expression/bioactivity was up-regulated under HG ambience in LLC-PK1 cells, a tubular cell line. We further investigated whether MIOX overexpression leads to accentuation of tubulo-interstitial injury, as gauged by some of the parameters relevant to the progression of DN. Under HG ambience, MIOX overexpression accentuated redox imbalance, perturbed NAD(+)/NADH ratios, increased ROS generation, depleted reduced glutathione, reduced GSH/GSSG ratio, and enhanced adaptive changes in the profile of the antioxidant defense system. These changes were also accompanied by mitochondrial dysfunctions, DNA damage and induction of apoptosis, accentuated activity of profibrogenic cytokine, and expression of fibronectin, the latter two being the major hallmarks of DN. These perturbations were largely blocked by various ROS inhibitors (Mito Q, diphenyleneiodonium chloride, and N-acetylcysteine) and MIOX/NOX4 siRNA. In conclusion, this study highlights a novel mechanism where MIOX under HG ambience exacerbates renal injury during the progression of diabetic nephropathy following the generation of excessive ROS via an unexplored G-X pathway.
Overexpression and hyperactivation of lymphocyte-specific protein tyrosine kinase (Lck) have been associated with leukemia development. We previously showed that, other than its known function as a cytoplasmic signal transducer, Lck also acts as a nuclear transcription factor in mouse leukemic cell
s. In the present study, we demonstrated the presence of nuclear Lck in human leukemic T cells and in primary cells. We further established a positive correlation between Lck nuclear localization and its kinase activity. Proteomic analysis identified CR6-interacting factor 1 (CRIF1) as one of the Lck-interacting proteins. CRIF1 and Lck association in the nucleus was confirmed both by immunofluorescence microscopy and co-immunoprecipitation in human leukemic T cells. Close-range interaction between Lck and CRIF1 was validated by in situ proximity ligation assay (PLA). Consistent with the role of nuclear CRIF1 as a tumor suppressor, CRIF1 silencing promotes leukemic T cell survival in the absence of growth factors. This protective effect can be recapitulated by endogenous Lck or reconstituted Lck in leukemic T cells. All together, our results support a novel function of nuclear Lck in promoting human leukemic T cell survival through interaction with a tumor suppressor. It has important implications in defining a paradigm shift of non-canonical protein tyrosine kinase signaling.
Kirby L, etal., Nat Commun. 2019 Aug 29;10(1):3887. doi: 10.1038/s41467-019-11638-3.
Oligodendrocyte precursor cells (OPCs) are abundant in the adult central nervous system, and have the capacity to regenerate oligodendrocytes and myelin. However, in inflammatory diseases such as multiple sclerosis (MS) remyelination is often incomplete. To investigate how neuroinflammation influenc
es OPCs, we perform in vivo fate-tracing in an inflammatory demyelinating mouse model. Here we report that OPC differentiation is inhibited by both effector T cells and IFNγ overexpression by astrocytes. IFNγ also reduces the absolute number of OPCs and alters remaining OPCs by inducing the immunoproteasome and MHC class I. In vitro, OPCs exposed to IFNγ cross-present antigen to cytotoxic CD8 T cells, resulting in OPC death. In human demyelinated MS brain lesions, but not normal appearing white matter, oligodendroglia exhibit enhanced expression of the immunoproteasome subunit PSMB8. Therefore, OPCs may be co-opted by the immune system in MS to perpetuate the autoimmune response, suggesting that inhibiting immune activation of OPCs may facilitate remyelination.
Mirgal D, etal., Trans R Soc Trop Med Hyg. 2016 May;110(5):294-8. doi: 10.1093/trstmh/trw026.
BACKGROUND: Recent studies in experimental mice have shown that mild deficiency of methylenetetrahydrofolate reductase (MTHFR) enzyme confers protection against malaria, thus providing an important basis for the hypothesis that MTHFR polymorphism, i.e. C677T, might have been subjected to
selection pressure against malaria. The present study was undertaken in a malaria endemic region in North East India to assess whether a similar selection advantage exists for other genes in folate metabolism pathway. METHODS: A total of 401 subjects including 131 symptomatic malaria, 97 asymptomatic malaria and 173 normal healthy controls were analysed for nine polymorphisms (single-nucleotide polymorphisms [SNPs] in eight genes and insertion/deletion in one gene): MTHFR C677T, methionine synthase reductase (MTRR) A66G, glutamate carboxypeptidase II (GCPII) C1561T, cystathionine beta-synthase (CBS) 844ins68, reduced folate carrier-1 (RFC-1) G80A, serine hydroxymethyltransferase (SHMT) C1420T, methionine synthase (MTR) A2756G, MTHFR G1793A (D 919G), glycine N-methyltransferase (GNMT) 1289 by PCR-RFLP technique. Differences in frequencies of genotype distribution of each polymorphic marker between these groups were evaluated. RESULTS: MTRR A2756G, SHMT C1420T, GCPII C1561T, MTRR A2756G and GNMT C1289T and RFC1 G80A polymorphisms showed significantly different prevalence between different groups analyzed. No significant differences were seen in the distribution of other polymorphisms. CONCLUSIONS: The study gives a clue for the possible selection of specific polymorphisms in the genes involved in the folate metabolism pathway by malaria parasite.
Congenital anomalies are the second highest cause of infant deaths, and, in most cases, diagnosis is a challenge. In this study, we characterize patterns of DNA copy number aberrations in different samples of post-mortem tissues from patients with congenital malformations. Twenty-eight patients und
ergoing autopsy were cytogenomically evaluated using several methods, specifically, Multiplex Ligation-dependent Probe Amplification (MLPA), microsatellite marker analysis with a MiniFiler kit, FISH, a cytogenomic array technique and bidirectional Sanger sequencing, which were performed on samples of different tissues (brain, heart, liver, skin and diaphragm) preserved in RNAlater, in formaldehyde or by paraffin-embedding. The results identified 13 patients with pathogenic copy number variations (CNVs). Of these, eight presented aneuploidies involving chromosomes 13, 18, 21, X and Y (two presented inter- and intra-tissue mosaicism). In addition, other abnormalities were found, including duplication of the TYMS gene (18p11.32); deletion of the CHL1 gene (3p26.3); deletion of the HIC1 gene (17p13.3); and deletion of the TOM1L2 gene (17p11.2). One patient had a pathogenic missense mutation of g.8535C>G (c.746C>G) in exon 7 of the FGFR3 gene consistent with Thanatophoric Dysplasia type I. Cytogenomic techniques were reliable for the analysis of autopsy material and allowed the identification of inter- and intra-tissue mosaicism and a better understanding of the pathogenesis of congenital malformations.
Chojnowski A, etal., Elife. 2015 Aug 27;4. doi: 10.7554/eLife.07759.
Hutchinson-Gilford progeria (HGPS) is a premature ageing syndrome caused by a mutation in LMNA, resulting in a truncated form of lamin A called progerin. Progerin triggers loss of the heterochromatic marker H3K27me3, and premature senescence, which is prevented by telomerase. However, the mechanism
how progerin causes disease remains unclear. Here, we describe an inducible cellular system to model HGPS and find that LAP2alpha (lamina-associated polypeptide-alpha) interacts with lamin A, while its interaction with progerin is significantly reduced. Super-resolution microscopy revealed that over 50% of telomeres localize to the lamina and that LAP2alpha association with telomeres is impaired in HGPS. This impaired interaction is central to HGPS since increasing LAP2alpha levels rescues progerin-induced proliferation defects and loss of H3K27me3, whereas lowering LAP2 levels exacerbates progerin-induced defects. These findings provide novel insights into the pathophysiology underlying HGPS, and how the nuclear lamina regulates proliferation and chromatin organization.
Plastic changes in motor cortex capillary structure and function were examined in three separate experiments in adult rats following prolonged exercise. The first two experiments employed T-two-star (T(2)*)-weighted and flow-alternating inversion recovery (FAIR) functional magnetic resonance imagin
g to assess chronic changes in blood volume and flow as a result of exercise. The third experiment used an antibody against the CD61 integrin expressed on developing capillaries to determine if motor cortex capillaries undergo structural modifications. In experiment 1, T(2)*-weighted images of forelimb regions of motor cortex were obtained following 30 days of either repetitive activity on a running wheel or relative inactivity. The proton signal intensity was markedly reduced in the motor cortex of exercised animals compared with that of controls. This reduction was not attributable to alterations of vascular iron levels. These results are therefore most consistent with increased capillary perfusion or blood volume of forelimb regions of motor cortex. FAIR images acquired during experiment 2 under normocapnic and hypercapnic conditions indicated that resting cerebral blood flow was not altered under normal conditions but was elevated in response to high levels of CO(2), suggesting that prolonged exercise increases the size of a capillary reserve. Finally, the immunohistological data indicated that exercise induces robust growth of capillaries (angiogenesis) within 30 days from the onset of the exercise regimen. Analysis of other regions failed to find any changes in perfusion or capillary structure suggesting that this motor activity-induced plasticity may be specific to motor cortex.These data indicate that capillary growth occurs in motor areas of the cerebral cortex as a robust adaptation to prolonged motor activity. In addition to capillary growth, the vascular system also experiences heightened flow under conditions of activation. These changes are chronic and observable even in the anesthetized animal and are measurable using noninvasive techniques.
Manubolu M, etal., J Ethnopharmacol. 2014 May 14;153(3):744-52. doi: 10.1016/j.jep.2014.03.040. Epub 2014 Mar 26.
ETHNOPHARMACOLOGICAL RELEVANCE: Actiniopteris radiata is a herb with great medicinal value and is evaluated for hepatoprotective activity. To investigate the protective effect of ethanolic extract of Actiniopteris radiata (EEAR) on CCl(4) induced oxidative stress in male Wistar albino rats. MATERIAL
S AND METHODS: EEAR were administered for 8 consecutive weeks to rats. Group I - control; Group II - toxin control (30% CCl(4)); Group III and Group IV received EEAR (250 and 500 mg/kg respectively). Antioxidant status in liver were estimated by determining the activities of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx); as well as by determining the levels of lipid peroxidation (LPO) and reduced glutathione (GSH). In addition, isoenzyme pattern and mRNA expression of the antioxidants were studied. Partial characterization of EEAR was performed by Liquid chromatography-mass spectrometry (LC-MS). RESULTS: CCl(4) induced oxidative stress as evidenced from increase in LPO along with reduction of SOD, CAT, GPx and GSH. Treatment with EEAR (250 and 500 mg/kg) mitigated the CCl(4) induced oxidative stress. An analysis of the isozyme pattern of these antioxidant enzymes revealed variations in SOD2, CAT, GPx2 and GPx3 in CCl(4) treated rats, which were normalized after EEAR treatment. Furthermore, expression of genes for the antioxidant enzymes, were down-regulated by CCl(4) treatment, which were reversed by EEAR. The results of partial characterization of EEAR by LC-MS revealed the presence of rutin and other 7 unknown phenolic derivatives. CONCLUSIONS: These findings suggest the protective effect of EEAR against CCl(4) induced oxidative stress might be attributed to the presence of flavonoids and phenolic compounds.
Pal M, etal., Tissue Cell. 2008 Dec;40(6):425-35. doi: 10.1016/j.tice.2008.04.003. Epub 2008 Jun 24.
Oral submucous fibrosis (OSF) is a precancerous condition of the oral cavity and oropharynx and a significant number of such cases transform into oral squamous cell carcinoma (OSCC). Presently, diagnosis of OSF is done mainly through qualitative histopathological techniques and in the level of diagn
ostic molecular biology no specific genetic marker is evident. Keeping these facts in mind this study evaluates histopathological changes in the epithelium and subepithelial connective tissue of OSF through quantitative digital image analysis in respect to specific candidate features and analyses null mutations in the GSTM1 and GSTT1 by PCR amplification. The analysis revealed that there are subtle quantitative differences in the histological images of OSF compared to NOM. The thickness of the epithelium and cell population in its different zones, radius of curvature of rete-ridges and connective tissue papillae were decreased but length of rete-ridges and connective tissue papillae, fibrocity and the number of cellular components (predominantly inflammatory cells) in the subepithelial connective tissue were increased in OSF. The PCR study revealed that there is no significant difference in the allelic variants in GSTM1 between OSF and normal, while GSTT1 null gene showed significantly higher frequencies in this precancerous condition. This study establishes a distinct quantitative difference between normal oral mucosa (NOM) and OSF in respect to their histological features and GST null gene frequencies.
Palijan A, etal., Physiol Genomics 2003 Sep 29;15(1):1-8.
Our previous linkage studies indicated that there might be a blood pressure (BP) quantitative trait locus (QTL) on chromosome 3 (Chr 3) contrasting between the Dahl salt-sensitive (S) strain and the Lewis (LEW) strain. To prove and then to narrow down the segment containing this QTL, five congenic s
trains have been generated by replacing various segments of the S rats with the homologous segments of the LEW rats. They are designated as S.L1, S.L2, S.L3, S.L4, and S.L5, respectively. S.L2, S.L3, S.L4, and S.L5 are substrains of S.L1, i.e., they contain substitutions of smaller sections within the large fragment defined by S.L1. The construction of these congenic strains was facilitated by a genome-wide marker screening process. BPs of the rats were measured by telemetry. S.L2 and S.L3 shared a fragment of Chr 3 in common and both showed a BP-lowering effect, indicating the existence of "-BP" QTL alleles from LEW compared with S. In contrast, S.L4 involves a section with no overlap with either S.L2 or S.L3, and S.L4 showed a BP significantly higher than that of S rats, indicating the presence of "+BP" QTL alleles from LEW compared with S. Interestingly, the combined effect of the -BP QTL and +BP QTL alleles was "-" in S.L1, implying that the "-" QTL is epistatic to "+" QTL.
Orlov SN, etal., Physiol Genomics 2001 Dec 21;7(2):171-7.
Both linkage and use of congenic strains have shown that a chromosome region near the gene for the Na-K-ATPase alpha(1)-subunit (Atp1a1) contained a quantitative trait locus (QTL) for blood pressure (BP). Currently, two congenic strains, designated S.M5 and S.M6, were made by replacing a segment of
the Dahl salt-sensitive SS/Jr (S) rat by the homologous region of the Milan normotensive rat (MNS). In S.M5, the gene for Atp1a1 is from the MNS strain; whereas in S.M6, Atp1a1 is from the S strain. The baseline activity of the alpha(1)-Na-K-ATPase and its stoichiometry were evaluated by an assay of ouabain-sensitive inwardly and outwardly directed (86)Rb and (22)Na fluxes in erythrocytes. The two congenic strains showed a similar BP, but both had a BP lower than that of S rats (P < 0.0001). Neither the alpha(1)-Na-K-ATPase activity nor its stoichiometry was affected by the substitution of the Atp1a1 alleles of S by those of MNS. Thus the BP-lowering effects observed in S.M5 and S.M6 could not be attributed to the alpha(1)-Na-K-ATPase activity or its stoichiometry. Atp1a1 is not supported as a candidate to be a BP QTL.
BACKGROUND: Overactivation of reticuloendothelial cells lining liver sinusoids - Kupffer cells (macrophages) and sinusoidal endothelial cells - may narrow the sinusoidal lumen, impair perfusion in liver microcirculation and contribute to disease severity in alcoholic hepatitis. AIM:
The aim of the article was to assess reticuloendothelial activation in patients with severe alcoholic hepatitis (SAH). METHODS: In SAH patients, we prospectively studied baseline reticuloendothelial activation markers [serum ferritin, sCD163 and plasma von Willebrand factor (VWF) antigen] and Macrophage Activation Syndrome (MAS) criteria, correlated them with disease severity scores [model for end-stage liver disease (MELD) and Sequential Organ Failure Assessment (SOFA) scores] and analyzed their ability to predict survival over a 90-day follow-up period. RESULTS: A total of 50 SAH patients [45 (37-49) years, median (interquartile range), 49 males, discriminant function, 76.2 (54.5-106.6); MELD score, 30 (26.2-36)] were studied. 41 SAH patients (82%) had ferritin >500 ng/mL, and all (100%) had markedly raised sCD163 and VWF levels. The median sCD163 level was 10-fold higher than healthy controls and the median VWF level was 5-fold above the upper limit of normal. In total, 37 SAH patients (74%) met MAS criteria. Reticuloendothelial activation markers correlated with MELD and SOFA scores (P < 0.05). VWF was an independent marker to predict mortality in SAH [adjusted hazard ratio, 1.002 (1.000-1.004)]. CONCLUSIONS: The reticuloendothelial system was markedly activated and correlated with disease severity scores in SAH patients.VWF predicted short-term mortality independent of MELD and sCD163. Further larger multicentric studies are needed to validate these findings.
Wang L, etal., Mol Cancer Res. 2010 Dec;8(12):1591-600. doi: 10.1158/1541-7786.MCR-10-0209. Epub 2010 Oct 27.
Although the importance of RGS-GAIP-interacting protein (GIPC) in the biology of malignant cells is well known, the molecular mechanism of GIPC in the inhibition of tumor progression has not been identified. This study focused on elucidating the molecular role of GIPC in breast cancer progression.
By using a human breast tumor specimen, an in vivo mouse model, and breast cancer cell lines, we showed for the first time that GIPC is involved in breast cancer progression through regulation of breast cancer cell proliferation, survival, and invasion. Furthermore, we found that the Akt/Mdm2/p53 axis, insulin-like growth factor-1 receptor, matrix metalloproteinase-9, and Cdc42 were downstream of GIPC signaling in breast cancer cells. Moreover, we showed that wild-type p53 reduced GIPC-induced breast cancer cell survival, whereas mutant p53 inhibited GIPC-induced cell invasion. Finally, we demonstrated that an N-myristoylated GIPC peptide (CR1023, N-myristoyl-PSQSSSEA) capable of blocking the PDZ domain of GIPC successfully inhibited MDA-MB-231 cell proliferation, survival, and further in vivo tumor growth. Taken together, these findings demonstrate the importance of GIPC in breast tumor progression, which has a potentially significant impact on the development of therapies against many common cancers expressing GIPC, including breast and renal cancer.
This study shows a decrease in soluble amyloid-beta protein precursor-alpha (sAbetaPPalpha) levels, but no change in sAbetaPPbeta, in the rat hippocampus during healthy aging, associated with the weaker expression of N-methyl-D-aspartate receptor (NMDAR)-dependent long-term potentiation (LTP) in the
CA1 area of hippocampal slices. Exogenous application of recombinant sAbetaPPalpha increases NMDAR activation in aged animals and could rescue the age-related LTP deficits described. In contrast, it does not affect basal synaptic transmission or glutamate release. These results indicate that improving synaptic sAbetaPPalpha availability at synapses helps in reducing the functional NMDAR-related deregulation of hippocampal networks linked to aging.
Shibata E, etal., Mol Cell Biol. 2011 Aug;31(15):3136-45. doi: 10.1128/MCB.05496-11. Epub 2011 May 31.
CRL4(Cdt2) is a cullin-based E3 ubiquitin ligase that promotes the ubiquitin-dependent proteolysis of various substrates implicated in the control of cell cycle and various DNA metabolic processes such as DNA replication and repair. Substrates for CRL4(Cdt2) E3 ubiquitin ligase include the replicati
on licensing factor Cdt1 and the cyclin-dependent kinase (Cdk) inhibitor p21. Inhibition of this E3 ligase leads to serious abnormalities of the cell cycle and cell death. The ubiquitin-conjugating enzyme (UBC) involved in this important pathway, however, remains unknown. By a proteomic analysis of Cdt2-associated proteins and an RNA interference-based screening approach, we show that CRL4(Cdt2) utilizes two different UBCs to target different substrates. UBCH8, a member of the UBE2E family of UBCs, ubiquitylates and promotes the degradation of p21, both during the normal cell cycle and in UV-irradiated cells. Importantly, depletion of UBCH8 by small interfering RNA (siRNA) increases p21 protein level, delays entry into S phase of the cell cycle, and suppresses the DNA damage response after UV irradiation. On the other hand, members of the UBE2G family of UBCs (UBE2G1 and UBE2G2) cooperate with CRL4(Cdt2) to polyubiquitylate and degrade Cdt1 postradiation, an activity that is critical for preventing origin licensing in DNA-damaged cells. Finally, we show that UBCH8, but not UBE2G1 or UBE2G2, is required for CRL4(Cdt2)-mediated ubiquitylation and degradation of the histone H4 lysine 20 monomethyltransferase Set8, a previously identified CRL4(Cdt2) substrate, as well as for CRL4(Cdt2)-dependent monoubiquitylation of PCNA in unstressed cells. These findings identify the UBCs required for the activity of CRL4(Cdt2) on multiple substrates and demonstrate that different UBCs are involved in the selective ubiquitylation of different substrates by the same E3 complex.
Coleman KE, etal., Genes Dev. 2015 Aug 15;29(16):1734-46. doi: 10.1101/gad.263731.115. Epub 2015 Aug 13.
Timely ubiquitin-mediated protein degradation is fundamental to cell cycle control, but the precise degradation order at each cell cycle phase transition is still unclear. We investigated the degradation order among substrates of a single human E3 ubiquitin ligase, CRL4(Cdt2), which mediates the S-p
hase degradation of key cell cycle proteins, including Cdt1, PR-Set7, and p21. Our analysis of synchronized cells and asynchronously proliferating live single cells revealed a consistent order of replication-coupled destruction during both S-phase entry and DNA repair; Cdt1 is destroyed first, whereas p21 destruction is always substantially later than that of Cdt1. These differences are attributable to the CRL4(Cdt2) targeting motif known as the PIP degron, which binds DNA-loaded proliferating cell nuclear antigen (PCNA(DNA)) and recruits CRL4(Cdt2). Fusing Cdt1's PIP degron to p21 causes p21 to be destroyed nearly concurrently with Cdt1 rather than consecutively. This accelerated degradation conferred by the Cdt1 PIP degron is accompanied by more effective Cdt2 recruitment by Cdt1 even though p21 has higher affinity for PCNA(DNA). Importantly, cells with artificially accelerated p21 degradation display evidence of stalled replication in mid-S phase and sensitivity to replication arrest. We therefore propose that sequential degradation ensures orderly S-phase progression to avoid replication stress and genome instability.
Circulating microRNAs (miRNA) have been intensely investigated as biomarkers in disease and therapy. Several studies have identified miR-122 as an important regulator of HCV replication. The effect of new therapies that directly target the HCV replication life cycle on circulating microRNA levels ha
s not been elucidated. We performed expression profiling of circulating miRNA in serum in subjects treated with HCV direct-acting antiviral agents (DAAs). Serum miRNA levels were evaluated from two studies in HCV GT1-infected treatment-naive subjects and prior nonresponders to pegylated interferon (pegIFN) and ribavirin (RBV) who received paritaprevir/ritonavir + dasabuvir + RBV for 12 weeks, and in treatment-naive genotype (GT)1-3-infected subjects who received paritaprevir/ritonavir + ombitasvir +/- RBV for 12 weeks. Over 100 different miRNA species were detected in serum. Of these, levels of miR-122 showed the most consistent change in response to treatment across all HCV genotypes. In all subjects, miR-122 showed an average four-fold reduction between baseline and week 2, and remained below baseline through post-treatment week 12 in subjects who achieved sustained virological response. In contrast, in subjects who did not achieve SVR, miR-122 levels began to return to baseline levels after the second week of treatment. The change in miR-122 levels was similar across genotypes, and was comparable with or without RBV. This is the first report comparing expression levels of circulating miRNA in HCV GT1-3 subjects treated with IFN-free combinations of DAAs. The results suggest that serum levels of miR-122 are reduced following treatment in subjects who achieve SVR, and correlate with HCV RNA levels across genotypes.
Pursuing fully a suggestion from linkage analysis that there might be a quantitative trait locus (QTL) for blood pressure (BP) in a Chromosome (Chr) 2 region of the Dahl salt-sensitive rat (DSS), four congenic strains were made by replacing various fragments of DSS Chr 2 with those of Lewis (LEW). C
onsequently, a BP QTL was localized to a segment of around 3 centiMorgan (cM) or near 3 megabases (Mbs) on Chr 2 by comparative congenics. The BPaugmenting alleles of this QTL originated from the LEW rat, a normotensive strain compared to DSS. The dissection of a QTL with such a paradoxical effect illustrated the power of congenics in unearthing a gene hidden in the context of the whole animal system presumably by interactions with other genes. The locus for the angiotensin II receptor AT1B (Agtr1b) is not supported as a candidate gene for the QTL because a congenic strain harboring it did not have an effect on BP. There are approximately 19 known and unknown genes present in the QTLinterval. Among them, no standout candidate genes are reputed to affect BP. Thus the QTL will likely represent a novel gene for BP regulation.
Joseph AM, etal., Exp Gerontol. 2013 Sep;48(9):858-68. doi: 10.1016/j.exger.2013.05.061. Epub 2013 Jun 7.
Aging is associated with a loss in muscle known as sarcopenia that is partially attributed to apoptosis. In aging rodents, caloric restriction (CR) increases health and longevity by improving mitochondrial function and the polyphenol resveratrol (RSV) has been reported to have similar benefits. In t
he present study, we investigated the potential efficacy of using short-term (6 weeks) CR (20%), RSV (50 mg/kg/day), or combined CR+ RSV (20% CR and 50 mg/kg/day RSV), initiated at late-life (27 months) to protect muscle against sarcopenia by altering mitochondrial function, biogenesis, content, and apoptotic signaling in both glycolytic white and oxidative red gastrocnemius muscle (WG and RG, respectively) of male Fischer 344 x Brown Norway rats. CR but not RSV attenuated the age-associated loss of muscle mass in both mixed gastrocnemius and soleus muscle, while combined treatment (CR + RSV) paradigms showed a protective effect in the soleus and plantaris muscle (P < 0.05). Sirt1 protein content was increased by 2.6-fold (P < 0.05) in WG but not RG muscle with RSV treatment, while CR or CR + RSV had no effect. PGC-1alpha levels were higher (2-fold) in the WG from CR-treated animals (P < 0.05) when compared to ad-libitum (AL) animals but no differences were observed in the RG with any treatment. Levels of the anti-apoptotic protein Bcl-2 were significantly higher (1.6-fold) in the WG muscle of RSV and CR + RSV groups compared to AL (P < 0.05) but tended to occur coincident with elevations in the pro-apoptotic protein Bax so that the apoptotic susceptibility as indicated by the Bax to Bcl-2 ratio was unchanged. There were no alterations in DNA fragmentation with any treatment in muscle from older animals. Additionally, mitochondrial respiration measured in permeabilized muscle fibers was unchanged in any treatment group and this paralleled the lack of change in cytochrome c oxidase (COX) activity. These data suggest that short-term moderate CR, RSV, or CR + RSV tended to modestly alter key mitochondrial regulatory and apoptotic signaling pathways in glycolytic muscle and this might contribute to the moderate protective effects against aging-induced muscle loss observed in this study.
Liu X, etal., Cell. 2024 May 9;187(10):2465-2484.e22. doi: 10.1016/j.cell.2024.04.005. Epub 2024 May 2.
Remyelination failure in diseases like multiple sclerosis (MS) was thought to involve suppressed maturation of oligodendrocyte precursors; however, oligodendrocytes are present in MS lesions yet lack myelin production. We found that oligodendrocytes in the lesions are epigenetically silenced. Develo
ping a transgenic reporter labeling differentiated oligodendrocytes for phenotypic screening, we identified a small-molecule epigenetic-silencing-inhibitor (ESI1) that enhances myelin production and ensheathment. ESI1 promotes remyelination in animal models of demyelination and enables de novo myelinogenesis on regenerated CNS axons. ESI1 treatment lengthened myelin sheaths in human iPSC-derived organoids and augmented (re)myelination in aged mice while reversing age-related cognitive decline. Multi-omics revealed that ESI1 induces an active chromatin landscape that activates myelinogenic pathways and reprograms metabolism. Notably, ESI1 triggered nuclear condensate formation of master lipid-metabolic regulators SREBP1/2, concentrating transcriptional co-activators to drive lipid/cholesterol biosynthesis. Our study highlights the potential of targeting epigenetic silencing to enable CNS myelin regeneration in demyelinating diseases and aging.
Disabled-1 (Dab1) plays a key role in reelin-mediated neuronal migration during brain development. Tyrosine phosphorylation of Dab1 at two YQXI and two YXVP motifs recruits multiple SH2 domains, resulting in activation of a wide range of signaling cascades. However, the molecular mechanisms underly
ing the coordinated regulation of Dab1 downstream effectors remain poorly understood. Here, we show that alternative splicing results in inclusion of different combinations of YQXI and YXVP motifs in Dab1 isoforms during development. Dab1 variants with partial or complete loss of YQXI motifs are preferentially expressed at early developmental stages, whereas the commonly studied Dab1 is predominantly expressed at late developmental stages. Expression of Dab1 variants in 293T and Neuro2a cells reveals reduced levels or absence of tyrosine phosphorylation in variants that have lost one or both YQXI motifs. We further demonstrate that Dab1 variants differ in their abilities to activate Src and recruit distinct SH2 domains involved in specific downstream signaling pathways. We propose that coordinated expression of specific Dab1 isoforms in different populations of cells in the developing brain contributes to precise neuronal migration by modulating the activity of subsets of Dab1 downstream effectors.
Arbore G, etal., Science. 2016 Jun 17;352(6292):aad1210. doi: 10.1126/science.aad1210.
The NLRP3 inflammasome controls interleukin-1beta maturation in antigen-presenting cells, but a direct role for NLRP3 in human adaptive immune cells has not been described. We found that the NLRP3 inflammasome assembles in human CD4(+) T cells and initiates caspase-1-dependent interleukin-1beta secr
etion, thereby promoting interferon-gamma production and T helper 1 (T(H)1) differentiation in an autocrine fashion. NLRP3 assembly requires intracellular C5 activation and stimulation of C5a receptor 1 (C5aR1), which is negatively regulated by surface-expressed C5aR2. Aberrant NLRP3 activity in T cells affects inflammatory responses in human autoinflammatory disease and in mouse models of inflammation and infection. Our results demonstrate that NLRP3 inflammasome activity is not confined to "innate immune cells" but is an integral component of normal adaptive T(H)1 responses.
Marciniak E, etal., Sci Rep. 2015 Oct 29;5:15862. doi: 10.1038/srep15862.
Chemokines are signaling molecules playing an important role in immune regulations. They are also thought to regulate brain development, neurogenesis and neuroendocrine functions. While chemokine upsurge has been associated with conditions characterized with cognitive impairments, their ability to m
odulate synaptic plasticity remains ill-defined. In the present study, we specifically evaluated the effects of MIP1-alpha/CCL3 towards hippocampal synaptic transmission, plasticity and spatial memory. We found that CCL3 (50 ng/ml) significantly reduced basal synaptic transmission at the Schaffer collateral-CA1 synapse without affecting NMDAR-mediated field potentials. This effect was ascribed to post-synaptic regulations, as CCL3 did not impact paired-pulse facilitation. While CCL3 did not modulate long-term depression (LTD), it significantly impaired long-term potentiation (LTP), an effect abolished by Maraviroc, a CCR5 specific antagonist. In addition, sub-chronic intracerebroventricular (icv) injections of CCL3 also impair LTP. In accordance with these electrophysiological findings, we demonstrated that the icv injection of CCL3 in mouse significantly impaired spatial memory abilities and long-term memory measured using the two-step Y-maze and passive avoidance tasks. These effects of CCL3 on memory were inhibited by Maraviroc. Altogether, these data suggest that the chemokine CCL3 is an hippocampal neuromodulator able to regulate synaptic plasticity mechanisms involved in learning and memory functions.
The fructose added to soft drinks and processed food, as well as frequent detection of vitamin D deficiency in the body, are two insults increasingly considered to cause lesions in target organs. We studied the liver after a chronic high-fructose diet deficient and supplemented with vitamin D. Sixty
C57BL/6 mature male mice were allocated into six groups (n = 10) for ten weeks: control (C), control deficient in vitamin D (CDD), control supplemented with vitamin D (CDS), fructose (F), fructose deficient in vitamin D (FDD), and fructose supplemented with vitamin D (FDS). The gene expressions of vitamin D receptor and CYP27B1 and 25 hydroxyvitamin D plasma level ensured that the diets caused vitamin D deficiency or supplementation. Body mass did not change, but blood pressure (BP) increased in CDD, F, and FDD, whereas BP was controlled in FDS. Insulinemia, insulin tolerance and resistance were seen in both vitamin D deficiency and fructose groups but improved with vitamin D supplementation. The steatosis and fibrosis were observed in the CDD, F and FDD groups. Also, F and FDD showed activation of stellate cells (HSC). Lipogenesis and inflammation gene expressions were enhanced in the CDD, F and FDD groups, but diminished with vitamin D supplementation. In conclusion, we demonstrated the adverse effects of vitamin D deficiency on metabolism, liver steatosis and, combined with fructose intake, liver interstitial fibrosis with hepatic stellate cell activation, and alteration of the lipogenesis, beta-oxidation, and liver inflammation. All these data improved when vitamin D was supplemented in the animals.
Ross MT, etal., Nature. 2005 Mar 17;434(7031):325-37.
The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise proc
ess that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence.
Dey BK, etal., Genes Dev. 2014 Mar 1;28(5):491-501. doi: 10.1101/gad.234419.113. Epub 2014 Feb 14.
Regulated expression of the H19 long noncoding RNA gene has been well characterized as a paradigm for genomic imprinting, but the H19 RNA's biological function remains largely unclear. H19 is abundantly expressed maternally in embryonic tissues but is strongly repressed after birth, and significant
transcription persists only in skeletal muscle. Thus, we examined the role of the H19 RNA in skeletal muscle differentiation and regeneration. Knockdown of H19 RNA in myoblast cells and H19 knockout mouse satellite cells decreases differentiation. H19 exon1 encodes two conserved microRNAs, miR-675-3p and miR-675-5p, both of which are induced during skeletal muscle differentiation. The inhibition of myogenesis by H19 depletion during myoblast differentiation is rescued by exogenous expression of miR-675-3p and miR-675-5p. H19-deficient mice display abnormal skeletal muscle regeneration after injury, which is rectified by reintroduction of miR-675-3p and miR-675-5p. miR-675-3p and miR-675-5p function by directly targeting and down-regulating the anti-differentiation Smad transcription factors critical for the bone morphogenetic protein (BMP) pathway and the DNA replication initiation factor Cdc6. Therefore, the H19 long noncoding RNA has a critical trans-regulatory function in skeletal muscle differentiation and regeneration that is mediated by the microRNAs encoded within H19.
Transportin-2 (TNPO2) mediates multiple pathways including non-classical nucleocytoplasmic shuttling of >60 cargoes, such as developmental and neuronal proteins. We identified 15 individuals carrying de novo coding variants in TNPO2 who presented with global developmental delay (GDD), dysmorphic fea
tures, ophthalmologic abnormalities, and neurological features. To assess the nature of these variants, functional studies were performed in Drosophila. We found that fly dTnpo (orthologous to TNPO2) is expressed in a subset of neurons. dTnpo is critical for neuronal maintenance and function as downregulating dTnpo in mature neurons using RNAi disrupts neuronal activity and survival. Altering the activity and expression of dTnpo using mutant alleles or RNAi causes developmental defects, including eye and wing deformities and lethality. These effects are dosage dependent as more severe phenotypes are associated with stronger dTnpo loss. Interestingly, similar phenotypes are observed with dTnpo upregulation and ectopic expression of TNPO2, showing that loss and gain of Transportin activity causes developmental defects. Further, proband-associated variants can cause more or less severe developmental abnormalities compared to wild-type TNPO2 when ectopically expressed. The impact of the variants tested seems to correlate with their position within the protein. Specifically, those that fall within the RAN binding domain cause more severe toxicity and those in the acidic loop are less toxic. Variants within the cargo binding domain show tissue-dependent effects. In summary, dTnpo is an essential gene in flies during development and in neurons. Further, proband-associated de novo variants within TNPO2 disrupt the function of the encoded protein. Hence, TNPO2 variants are causative for neurodevelopmental abnormalities.
Tominaga T, etal., J Biol Chem. 2016 Jan 15;291(3):1348-67. doi: 10.1074/jbc.M115.698191. Epub 2015 Nov 17.
The kidney is one of the target organs for various metabolic diseases, including diabetes, metabolic syndrome, and obesity. Most of the metabolic studies underscore glomerular pathobiology, although the tubulo-interstitial compartment has been underemphasized. This study highlights mechanisms conc
erning the pathobiology of tubular injury in the context of myo-inositol oxygenase (Miox), a tubular enzyme. The kidneys of mice fed a high fat diet (HFD) had increased Miox expression and activity, and the latter was related to phosphorylation of serine/threonine residues. Also, expression of sterol regulatory element-binding protein1 (Srebp1) and markers of cellular/nuclear damage was increased along with accentuated apoptosis and loss of tubular brush border. Similar results were observed in cells treated with palmitate/BSA. Multiple sterol-response elements and E-box motifs were found in the miox promoter, and its activity was modulated by palmitate/BSA. Electrophoretic mobility and ChIP assays confirmed binding of Srebp to consensus sequences of the miox promoter. Exposure of palmitate/BSA-treated cells to rapamycin normalized Miox expression and prevented Srebp1 nuclear translocation. In addition, rapamycin treatment reduced p53 expression and apoptosis. Like rapamycin, srebp siRNA reduced Miox expression. Increased expression of Miox was associated with the generation of reactive oxygen species (ROS) in kidney tubules of mice fed an HFD and cell exposed to palmitate/BSA. Both miox and srebp1 siRNAs reduced generation of ROS. Collectively, these findings suggest that HFD or fatty acids modulate transcriptional, translational, and post-translational regulation of Miox expression/activity and underscore Miox being a novel target of the transcription factor Srebp1. Conceivably, activation of the mTORC1/Srebp1/Miox pathway leads to the generation of ROS culminating into tubulo-interstitial injury in states of obesity.
The intracerebroventricular infusion of streptozotocin (icv-STZ) has been largely used in research to mimic the main characteristics of Alzheimer's disease (AD), including cognitive decline, impairment of cholinergic transmission, oxidative stress and astrogliosis. Moderate physical exercise has a n
umber of beneficial effects on the central nervous system, as demonstrated both in animals and in human studies. This study aimed to evaluate the effect of 5-week treadmill training, in the icv-SZT model of sporadic AD, on cognitive function, oxidative stress (particularly mediated by NO) and on the astrocyte marker proteins, glial fibrillary acidic protein (GFAP) and S100B. Results confirm the spatial cognitive deficit and oxidative stress in this model, as well as astroglial alterations, particularly a decrease in CSF S100B. Physical exercise prevented these alterations, as well as increasing the hippocampal content of glutathione and GFAP per se in the CA1 region. These findings reinforce the potential neuroprotective role of moderate physical exercise. Astroglial changes observed in this dementia model contribute to understanding AD and other diseases that are accompanied by cognitive deficit.
Trerotola M, etal., Oncotarget. 2015 Jun 10;6(16):14318-28.
In this study, we show that the transmembrane glycoprotein Trop-2 is up-regulated in human prostate cancer (PCa) with extracapsular extension (stages pT3/pT4) as compared to organ-confined (stage pT2) PCa. Consistent with this evidence, Trop-2 expression is found to be increased in metastatic prosta
te tumors of Transgenic Adenocarcinoma of Mouse Prostate mice and to strongly correlate with alpha5beta1 integrin levels. Using PCa cells, we show that Trop-2 specifically associates with the alpha5 integrin subunit, as binding to alpha3 is not observed, and that Trop-2 displaces focal adhesion kinase from focal contacts. In support of the role of Trop-2 as a promoter of PCa metastatic phenotype, we observe high expression of this molecule in exosomes purified from Trop-2-positive PCa cells. These vesicles are then found to promote migration of Trop-2-negative PCa cells on fibronectin, an alpha5beta1 integrin/focal adhesion kinase substrate, thus suggesting that the biological function of Trop-2 may be propagated to recipient cells. In summary, our findings show that Trop-2 promotes an alpha5beta1 integrin-dependent pro-metastatic signaling pathway in PCa cells and that the altered expression of Trop-2 may be utilized for early identification of capsule-invading PCa.
Picher-Martel V, etal., Mol Brain. 2015 Oct 31;8(1):71. doi: 10.1186/s13041-015-0162-6.
BACKGROUND: Mutations in the gene encoding Ubiquilin-2 (UBQLN2) are linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). UBQLN2 plays a central role in ubiquitin proteasome system (UPS) and UBQLN2 mutants can form cytoplasmic aggregates in vitro and in vivo. RESULTS: Her
e, we report that overexpression of WT or mutant UBQLN2 species enhanced nuclear factor kappaB (NF-kappaB) activation in Neuro2A cells. The inhibition of NF-kappaB stress-mediated activation with SB203580, a p38 MAPK inhibitor, demonstrated a role for MAPK in NF-kappaB activation by UBQLN2 species. Live cell imaging and microscopy showed that UBQLN2 aggregates are dynamic structures that promote cytoplasmic accumulation of TAR DNA-binding protein (TDP-43), a major component of ALS inclusion bodies. Furthermore, up-regulation of UBQLN2 species in neurons caused an ER-stress response and increased their vulnerability to death by toxic mediator TNF-alpha. Withaferin A, a known NF-kappaB inhibitor, reduced mortality of Neuro2A cells overexpressing UBQLN2 species. CONCLUSIONS: These results suggest that UBQLN2 dysregulation in neurons can drive NF-kappaB activation and cytosolic TDP-43 aggregation, supporting the concept of pathway convergence in ALS pathogenesis. These Ubiquilin-2 pathogenic pathways might represent suitable therapeutic targets for future ALS treatment.
Hu X, etal., Proc Natl Acad Sci U S A. 2013 Jun 18;110(25):10213-8. doi: 10.1073/pnas.1221243110. Epub 2013 Jun 3.
Tumor suppressors known to date impede cancer growth by arresting the cell cycle or promoting apoptosis. Here we show that unphosphorylated human STAT5A functions as a tumor suppressor capable of repressing multiple oncogenes via heterochromatin formation. Unphosphorylated STAT5A binds to heterochr
omatin protein 1alpha (HP1alpha) and stabilizes heterochromatin. Expressing unphosphorylated STAT5A or HP1alpha inhibits colon cancer growth in mouse xenograft models. Transcriptome profiling shows that expressing an unphosphorylatable STAT5A has similar effects to overexpressing HP1alpha in global gene expression. Notably, the majority of the genes commonly repressed by unphosphorylated STAT5A and HP1alpha have been implicated in cancer development. Finally, down-regulation, somatic mutations, and deletions of STAT5 genes are found in certain human cancers. These results suggest that unphosphorylated STAT5A may epigenetically suppress tumor growth by promoting heterochromatin formation.
A broad Chromosome (Chr) 10 region of the Dahl salt-sensitive (S) rat was shown by linkage and the use of congenic strains to contain a blood pressure (BP) quantitative trait locus (QTL). To further narrow down the region harboring the QTL, four congenic strains carrying smaller segments were made b
y replacing various segments of the S rats with the homologous segments of the Lewis (LEW) rats. The construction of these congenic strains was facilitated by a genome-wide marker screening. One congenic strain, assigned as S.L4, showed a BP-lowering effect, and the region harboring a BP QTL, designated QTL1, is localized to a segment of about 15 cM. Two other strains, assigned as S.L2 and S.L5, contained an overlapping segment, and both showed a BP-lowering effect. In contrast, the fourth congenic strain, assigned as S.L1, contained a smaller and shared fragment with S.L2 and S.L5, but it did not have a BP-lowering effect. Deducing from the segment in common in S.L2 and S.L5, and not shared between S.L1 and both congenic strains S.L2 and S.L5, the region harboring a QTL, designated as QTL2, was narrowed to about 12 cM. The current work showed the general applicability of the 'speed congenic' approach to map and fine-map BP QTL.
A small supernumerary marker chromosome (sSMC) derived from chromosome 22 is a relatively common cytogenetic finding. This sSMC typically results in tetrasomy for a chromosomal region that spans the chromosome 22p arm and the proximal 2 Mb of 22q11.21. Using classical cytogenetics, fluorescence in
situ hybridization, multiplex ligation-dependent probe amplification, and array techniques, 7 patients with sSMCs derived from chromosome 22 were studied: 4 non-related and 3 from the same family (mother, daughter, and son). The sSMCs in all patients were dicentric and bisatellited chromosomes with breakpoints in the chromosome 22 low-copy repeat A region, resulting in cat eye syndrome (CES) due to chromosome 22 partial tetrasomy 22pter-->q11.2 including the cat eye chromosome region. Although all subjects presented the same chromosomal abnormality, they showed a wide range of phenotypic differences, even in the 3 patients from the same family. There are no previous reports of CES occurring within 3 patients in the same family. Thus, the clinical and follow-up data presented here contribute to a better delineation of the phenotypes and outcomes of CES patients and will be useful for genetic counseling.
The pleiotropic actions of interleukin-2 (IL-2) are essential for regulation of immune responses and maintenance of immune tolerance. The IL-2 receptor (IL-2R) is composed of IL-2Rα, IL-2Rβ, and IL-2Rγ subunits, with defects in IL-2Rα and IL-2Rγ and their downstream signaling
effectors resulting in known primary immunodeficiency disorders. Here, we report the first human defect in IL-2Rβ, occurring in two infant siblings with a homozygous IL2RB mutation in the WSXWS motif, manifesting as multisystem autoimmunity and susceptibility to CMV infection. The hypomorphic mutation results in diminished IL-2Rβ surface expression and dysregulated IL-2/15 signaling, with an anticipated reduction in regulatory T cells. However, in contrast to the IL-2Rβ-/- animal model, which lacks NK cells, these siblings demonstrate an expansion of NK cells, particularly the CD56bright subset, and a lack of terminally differentiated NK cells. Thus, the early-onset autoimmunity and immunodeficiency are linked to functional deficits arising from altered IL-2Rβ expression and signaling in T and NK cells.
Gingras MC, etal., Cell Rep. 2016 Feb 2;14(4):907-19. doi: 10.1016/j.celrep.2015.12.005. Epub 2016 Jan 21.
The ampulla of Vater is a complex cellular environment from which adenocarcinomas arise to form a group of histopathologically heterogenous tumors. To evaluate the molecular features of these tumors, 98 ampullary adenocarcinomas were evaluated and compared to 44 distal bile duct and 18 duodenal aden
ocarcinomas. Genomic analyses revealed mutations in the WNT signaling pathway among half of the patients and in all three adenocarcinomas irrespective of their origin and histological morphology. These tumors were characterized by a high frequency of inactivating mutations of ELF3, a high rate of microsatellite instability, and common focal deletions and amplifications, suggesting common attributes in the molecular pathogenesis are at play in these tumors. The high frequency of WNT pathway activating mutation, coupled with small-molecule inhibitors of beta-catenin in clinical trials, suggests future treatment decisions for these patients may be guided by genomic analysis.
Jerosch-Herold M, etal., Am J Physiol Heart Circ Physiol. 2008 Sep;295(3):H1234-H1242. doi: 10.1152/ajpheart.00429.2008. Epub 2008 Jul 25.
Idiopathic dilated cardiomyopathy (IDC) is characterized by left ventricular (LV) enlargement with systolic dysfunction, other causes excluded. When inherited, it represents familial dilated cardiomyopathy (FDC). We hypothesized that IDC or FDC would show with cardiac magnetic resonance (CMR) incre
ased myocardial accumulation of gadolinium contrast at steady state and decreased baseline myocardial blood flow (MBF) due to structural alterations of the extracellular matrix compared with normal myocardium. CMR was performed in nine persons affected with IDC/FDC. Healthy controls came from the general population (n = 6) or were unaffected family members of FDC patients (n = 3) without signs or symptoms of IDC/FDC or any structural cardiac abnormalities. The myocardial partition coefficient for gadolinium contrast (lambda(Gd)) was determined by T1 measurements. LV shape and function and MBF were assessed by standard CMR methods. lambda(Gd) was elevated in IDC/FDC patients vs. healthy controls (lambda(Gd) = 0.56 +/- 0.15 vs. 0.41 +/- 0.06; P = 0.002), and correlated with LV enlargement (r = 0.61 for lambda(Gd) vs. end-diastolic volume indexed by height; P < 0.01) and with ejection fraction (r = -0.80; P < 0.001). The extracellular volume fraction was higher in IDC patients than in healthy controls (0.31 +/- 0.05 vs. 0.24 +/- 0.03; P = 0.002). Resting MBF was lower in IDC patients (0.64 +/- 0.13 vs. 0.91 +/- 0.22; P = 0.01) than unaffected controls and correlated with both the partition coefficient (r = -0.57; P = 0.012) and the extracellular volume fraction (r = -0.56; P = 0.019). The expansion of the extracellular space correlated with reduced MBF and ventricular dilation. Expansion of the extracellular matrix may be a key contributor to contractile dysfunction in IDC patients.
Dezerega A, etal., J Periodontol. 2010 Feb;81(2):267-76.
BACKGROUND: Chemokines are central in the activation and direction of leukocyte subsets to target tissues. However, the monocyte chemoattractant protein-3 (MCP-3) has not been associated with chronic periodontitis. Chronic periodontitis is an infection showing episodic supporting tissue destruction.
The aim of this study is to determine the levels and expression of MCP-3 in periodontal sites characterized by active periodontal connective tissue destruction. METHODS: The study population consisted of 15 patients with a progression of periodontitis (15 of 56 patients), 18 patients with chronic periodontitis, and 10 healthy subjects without periodontal disease. As determined by the tolerance method, the 15 patients with moderate to advanced chronic periodontitis showed a progression of periodontitis over a 4-month period. Periodontitis was characterized by at least six sites with a probing depth >or=5 mm, clinical attachment level >or=3 mm, and radiographic bone loss. Gingival crevicular fluid was collected using a paper strip. The total protein concentration was determined. An enzyme-linked immunosorbent assay was performed to determine the total amount of MCP-3, and an immunoWestern blot was conducted to assess molecular MCP-3 forms. To determine the MCP-3 expression by immunohistochemistry, gingival biopsies were obtained from patients with chronic periodontitis and healthy subjects during third-molar extraction surgery. Statistical analyses were performed using statistical software. Data were expressed as subject means +/- SD, using the chi(2) and Student t tests. RESULTS: The total amount and concentration of chemokine MCP-3 were significantly higher in patients with chronic periodontitis than in healthy subjects (8.25 pg versus 0.53 pg, P = 0.006 and 2.95 pg/microl versus 0.45 pg/microl, P = 0.04, respectively). Active sites showed a significantly higher total amount and concentration of MCP-3 than inactive sites (11.12 versus 2.88 pg, P value = 0.005 and 3.95 versus 1.02, P value = 0.005, respectively). Western blot and immunohistochemical staining confirmed the presence of MCP-3 in periodontal disease, with observable differences between patients with chronic periodontitis and healthy subjects. CONCLUSIONS: MCP-3 was highly expressed in patients with chronic periodontitis, particularly in those with progressive periodontal lesions. MCP-3 could be involved in the recruitment of inflammatory cells toward periodontal tissues during the progression of the disease.
Deficiency of carbohydrate sulfotransferase 3 (CHST3; also known as chondroitin-6-sulfotransferase) has been reported in a single kindred so far and in association with a phenotype of severe chondrodysplasia with progressive spinal involvement. We report eight CHST3 mutations in six unrelated indivi
duals who presented at birth with congenital joint dislocations. These patients had been given a diagnosis of either Larsen syndrome (three individuals) or humero-spinal dysostosis (three individuals), and their clinical features included congenital dislocation of the knees, elbow joint dysplasia with subluxation and limited extension, hip dysplasia or dislocation, clubfoot, short stature, and kyphoscoliosis developing in late childhood. Analysis of chondroitin sulfate proteoglycans in dermal fibroblasts showed markedly decreased 6-O-sulfation but enhanced 4-O-sulfation, confirming functional impairment of CHST3 and distinguishing them from diastrophic dysplasia sulphate transporter (DTDST)-deficient cells. These observations provide a molecular basis for recessive Larsen syndrome and indicate that recessive Larsen syndrome, humero-spinal dysostosis, and spondyloepiphyseal dysplasia Omani type form a phenotypic spectrum.
There is a high incidence of Niemann-Pick type B disease in the Maghreb region of North Africa, which includes Morocco, Algeria and Tunisia. A hypothesis that there may well be a common, predominant mutant acid sphingomyelinase allele responsible for the type B phenotype in this population has been
tested. A deletion of an arginine codon at amino acid residue 608 was found in one patient. The same mutation was also observed in another of our cases. An original screening procedure using 3'-end digoxigenin-labeled allele-specific oligonucleotides and chemiluminescent detection was developed and used parallel to the conventional assay with 5'-end radiolabeled oligonucleotides. Of the 15 non-related, non-Jewish North African type B patients studied, 12 were homozygous and two compound heterozygous for this deletion (26 delta R608 alleles/30 mutant alleles). Among type B patients from other geographic regions (France, UK, Italy, Czechoslovakia), this mutation was observed in only one of the 16 alleles studied. Our results indicate that deletion of arginine 608 in the acid sphingomyelinase gene is the highly prevalent mutation underlying Niemann-Pick type B disease in the population of Maghreb. A varying severity of the clinical and enzymatic expression within the non-neuronopathic phenotype has however been observed in patients homozygous for the mutation.
OBJECTIVE: The aim of this study was to investigate whether fibroblast growth factor receptor 4 (FGFR4) could serve as a potential therapeutic target, prognostic biomarker or biomarker predicting radiotherapy sensitivity in oral squamous cell carcinoma (OSCC) and oropharyngeal squamous cell carcinom
a (OPSCC). METHODS: FGFR4 immunohistochemistry and FGFR4/CEN5q FISH were performed on tissue microarrays from 212 OSCC and 238 OPSCC patients. FGFR4 genotypes were determined by PCR and DNA sequencing in 76 random OPSCC samples. The response to radiotherapy was evaluated 3 months after the last radiotherapy treatment session by a head and neck radiation oncologist and/or surgeon during clinic visits. The results were correlated to overall survival and response to radiotherapy. RESULTS: The FGFR4 protein was overexpressed in 64% (153/238) of OPSCCs and 41% (87/212) of OSCCs. The FGFR4 gene was amplified in 0.47% (1/212) of OSCCs and 0.42% (1/238) of OPSCCs, and the FGFR4 Gly388Arg polymorphism was detected in 62% (47/76) of OPSCCs. FGFR4 protein expression, FGFR4 gene copy numbers and FGFR4 genotypes were not related to overall survival or response to radiotherapy in OSCC or OPSCC. CONCLUSION: FGFR4 is frequently overexpressed in OSCC and OPSCC in the absence of gene amplification, and may serve as a potential predictive marker for FGFR4-directed targeted therapy in OSCC and OPSCC.
Several genome-wide screens for asthma and related phenotypes have been published to date but data on fine-mapping are scarce. For higher resolution we performed a fine-mapping study with 2 cM average spacing in often discussed asthma candidate regions (2p, 5q, 6p, 7p, 9q, 11p, and 12q) to narrow do
wn the regions of interest. All participants of a Caucasian family study (97 families with at least two affected sib pairs) were genotyped for 49 supplementary polymorphic dinucleotide markers. Our results indicate increased evidence for linkage on chromosome 6p, 9q, and 12q. These candidate regions were further analyzed with SNP polymorphisms in the endothelin 1 (EDN1), lymphotoxin alpha (LTA), and neuronal nitric oxide synthase (NOS1) genes. In addition, IL4 -590C>T and IL10 -592C>A, localized on chromosomes 5q and 1q, respectively, have been analyzed for SNP association. Of the six SNPs tested, four revealed weak association with the examined phenotypes. These are the IL10 -592C>A SNP in the interleukin 10 gene (p=0.036 for eosinophil cell counts), the 4124T>C SNP in EDN1 (p=0.044 for asthma), the 3391C>T SNP in NOS1 with eosinophil cell counts (p=0.0086), and the 5266C>T polymorphism, also in the NOS1 gene, for high IgE levels (p=0.022). In summary, fine mapping data enable us to confine asthma candidate regions, while variants of EDN1 and NOS1, or nearby genes, may play an important role in this context.
Kolb AF, etal., Biochem J. 2019 Oct 15;476(19):2769-2795. doi: 10.1042/BCJ20190275.
Elevated serum homocysteine, an intermediate of cellular one-carbon metabolism, is an independent risk factor for cardiovascular disease (CVD). Folate deficiency increases serum homocysteine and may contribute to CVD progression. Vascular smooth muscle cells (VSMCs) regulate vascular contractility,
but also contribute to repair processes in response to vascular injury. Nutritional deficiencies, like folate deficiency, are thought to impact on this phenotypic plasticity, possibly by epigenetic mechanisms. We have investigated the effect of folate deficiency on VSMCs in two cell culture systems representing early and late stages of smooth muscle cells differentiation. We find that folate deficiency promotes differentiation towards a more contractile phenotype as indicated by increased expression of respective marker genes. However, microarray analysis identified markers of striated muscle as the predominant gene expression change elicited by folate deficiency. These changes are not merely a reflection of cell cycle arrest, as foetal calf serum restriction or iron deficiency do not replicate the gene expression changes observed in response to folate deficiency. Folate deficiency only has a marginal effect on global DNA methylation. DNA methylation of CpG islands associated with genes regulated by folate deficiency remains unaffected. This supports our earlier findings in a mouse model system which also did not show any changes in global DNA methylation in response to folate and vitamin B6/B12 deficiency. These data suggest that folate deficiency enhances the expression of smooth muscle marker gene expression, promotes a shift towards a skeletal muscle phenotype, and does not regulate gene expression via DNA methylation.
Deuchars KL, etal., Biochim Biophys Acta 1992 Mar 24;1130(2):157-65.
In higher vertebrates, P-glycoprotein is usually encoded by a small family of genes. We have determined that the rat contains three P-glycoprotein genes and have cloned distinct genomic fragments containing the putative 3' untranslated regions of these P-glycoprotein genes. Sequence analysis indicat
es that the rat P-glycoprotein genes belong to the three P-glycoprotein classes identified in mammals. These cloned sequences will be useful for delineating the expression of P-glycoprotein genes in the rat. We have also isolated a fourth clone which contains only a short, but highly conserved P-glycoprotein domain. This clone appears not be a member of the P-glycoprotein gene family, and its relationship to P-glycoprotein is unknown.
BACKGROUND: Chondrosarcomas are the second most frequent primary malignant type of bone tumor. No effective systemic treatment has been identified in advanced or adjuvant phases for chondrosarcoma. The aim of the present study was to determine the antitumor effects of doxorubicin and everolimus, an
mTOR inhibitor on chondrosarcoma progression. METHODS AND FINDINGS: Doxorubin and/or everolimus were tested in vivo as single agent or in combination in the rat orthotopic Schwarm chondrosarcoma model, in macroscopic phase, as well as with microscopic residual disease. Response to everolimus and/or doxorubicin was evaluated using chondrosarcoma volume evolution (MRI). Histological response was evaluated with % of tumor necrosis, tumor proliferation index, metabolism quantification analysis between the treated and control groups. Statistical analyses were performed using chi square, Fishers exact test. Doxorubicin single agent has no effect of tumor growth as compared to no treatment; conversely, everolimus single agent significantly inhibited tumor progression in macroscopic tumors with no synergistic additive effect with doxorubicin. Everolimus inhibited chondrosarcoma proliferation as evaluated by Ki67 expression did not induce the apoptosis of tumor cells; everolimus reduced Glut1 and 4EBP1 expression. Importantly when given in rats with microscopic residual diseases, in a pseudo neoadjuvant setting, following R1 resection of the implanted tumor, everolimus significantly delayed or prevented tumor recurrence. CONCLUSIONS: MTOR inhibitor everolimus blocks cell proliferation, Glut1 expression and HIF1a expression, and prevents in vivo chondrosarcoma tumor progression in both macroscopic and in adjuvant phase post R1 resection. Taken together, our preclinical data indicate that mTOR inhibitor may be effective as a single agent in treating chondrosarcoma patients. A clinical trial evaluating mTOr inhibitor as neo-adjuvant and adjuvant therapy in chondrosarcoma patients is being constructed.
Dezerega A, etal., Int Endod J. 2010 Oct;43(10):902-8. doi: 10.1111/j.1365-2591.2010.01764.x. Epub 2010 Jul 15.
AIM: To study the expression of monocyte chemotactic protein-3 (MCP-3, also known as chemokine CCL-7) in tissue from apical lesions (AL) and to associate MCP-3 expression with symptomatic or asymptomatic apical periodontitis. METHODOLOGY: To determine the expression of MCP-3 in AL, biopsies obtained
during tooth extraction procedures were fixed, subjected to routine processing and diagnosed as apical granuloma (AG) (n = 7) or radicular cyst (RC) (n = 5). As controls, apical periodontal ligament (PDL) specimens from healthy premolars extracted for orthodontics reasons were included (n = 7). All specimens were immunostained for MCP-3 and examined under a light microscope. In addition, homogenates from AL (n = 14) and healthy PDL samples (n = 7) were studied through immunowestern blot. Finally, periapical exudates samples were collected from root canals of teeth having diagnosis of symptomatic (n = 14) and asymptomatic apical periodontitis (n = 14) during routine endodontic treatments and analysed by immunowestern blot and densitometry. RESULTS: MCP-3 was detected in AG and RC and localized mainly to inflammatory leucocytes, whereas no expression was observed in healthy PDLs. MCP-3 was also detected in periapical exudate, and its levels were significantly higher in symptomatic than in asymptomatic apical periodontitis. CONCLUSIONS: MCP-3 was expressed in AL and its levels associated with clinical symptoms. MCP-3 might play a role in disease pathogenesis, possibly by stimulating mononuclear chemotaxis.
Inflammatory disorders of the bowel and colon cancer are associated with elevated indices of oxidative stress. Analogous elevations in markers of oxidative stress and loss of cell-membrane integrity are also observed in the colons of rats deficient in vitamin E (D-alpha-tocopherol), the major lipid-
soluble antioxidant in biological systems. The causal relationship between colon pathologies associated with oxidative stress and dietary deficiency in antioxidant vitamins such as vitamin E is still uncertain. Investigation of potential mechanisms by which lack of dietary vitamin E may lead to clinically relevant pathological changes in colon tissue was conducted using gene expression profiling strategies on vitamin E-sufficient and -deficient rats. Morphological changes and increased indices of lipid peroxidation were linked to vitamin E deficiency. These changes in colon tissue are potentially important in disease pathogenesis of the colon linked with oxidative stress or other direct consequences of inadequate levels of vitamin E.
Immediate postnatal overfeeding in rats, obtained by reducing the litter size, results in early-onset obesity. Such experimental paradigm programs overweight, insulin resistance, dyslipidemia, increased adipose glucocorticoid metabolism [up-regulation of glucocorticoid receptor (GR) and 11beta-hydro
xysteroid dehydrogenase type 1 (11beta-HSD1)], and overexpression of proinflammatory cytokines in mesenteric adipose tissue (MAT) in adulthood. We studied the effects of pioglitazone, a PPARgamma agonist, treatment on the above-mentioned overfeeding-induced alterations. Nine-month-old rats normofed or overfed during the immediate postnatal period were given pioglitazone (3 mg/kg/day) for 6 weeks. Pioglitazone stimulated weight gain and induced a redistribution of adipose tissue toward epididymal location with enhanced plasma adiponectin. Treatment normalized postnatal overfeeding-induced metabolic alterations (increased fasting insulinemia and free fatty acids) and mesenteric overexpression of GR, 11beta-HSD11, CD 68, and proinflammatory cytokines mRNAs, including plasminogen-activator inhibitor type 1. Mesenteric GR mRNA levels correlated positively with mesenteric proinflammatory cytokines mRNA concentrations. In vitro incubation of MAT obtained from overfed rats demonstrated that pioglitazone induced a down-regulation of GR gene expression and normalized glucocorticoid-induced stimulation of 11beta-HSD1 and plasminogen-activator inhibitor type 1 mRNAs. Our data show for the first time that the metabolic, endocrine, and inflammatory alterations induced by early-onset postnatal obesity can be reversed by pioglitazone at the adulthood. They demonstrate that pioglitazone, in addition to its well-established effect on adipose tissue redistribution and adiponectin secretion, reverses programing-induced adipose GR, 11beta-HSD1, and proinflammatory cytokines overexpression, possibly through a GR-dependent mechanism.
Drew JE, etal., Biochem Pharmacol. 2005 Sep 15;70(6):888-93. doi: 10.1016/j.bcp.2005.06.011.
Oxidative stress is a characteristic of cancerous colon tissue and inflammatory bowel diseases that increase colon cancer risk. Epidemiological evidence supports a protective effect of plant-derived compounds. Aspirin is also protective against colon cancer. The mechanism of action is unclear althou
gh salicylic acid, the main metabolite of aspirin, has been shown to decrease the synthesis of pro-inflammatory and potentially neo-plastic prostaglandins. Salicylic acid is found in significant quantities in a plant-based diet. However, in plants salicylic acid is also reported to modulate the expression of numerous enzymes with antioxidant activity. The aim of this study was to assess whether salicylic acid can modulate pro-cancerous biological pathways in the colon. Oxidative stress, prostaglandins and cytosolic glutathione peroxidase (cyGPX) were analysed in proximal, transverse and distal colon from a rat model of diet-induced oxidative stress. Elevated plasma pyruvate kinase activity (1293+/-206 U/ml) and increased indices of lipid peroxidation in colon (proximal 6.4+/-0.84 nM MDA/mg protein; transverse 6.9+/-0.97 nM MDA/mg protein; distal 5.2+/-0.62 nM MDA/mg protein) from rats fed a Vitamin E deficient diet were significantly decreased on supplementation with salicylic acid (plasma pyruvate 546+/-43 U/ml; salicylic acid proximal 3.6+/-0.39 nM MDA/mg protein; transverse 4.5+/-0.61 nM MDA/mg protein; distal 4.4+/-0.27 nM MDA/mg protein). Reductions in oxidative stress and prostaglandin production on supplementation with salicylic acid were associated with an elevation in glutathione peroxidase activity (Vitamin E deficient proximal 0.056+/-0.013 U/mg protein; transverse 0.073+/-0.008 U/mg protein; distal 0.088+/-0.010 U/mg protein; Vitamin E deficient with salicylic acid proximal 0.17+/-0.01 U/mg protein; transverse 0.23+/-0.016 U/mg protein; distal 0.16+/-0.020 U/mg protein). Gpx1 and Gpx2 gene transcripts were not elevated in association with increased activity of the soluble glutathione peroxidase activity. Glutathione peroxidases are key antioxidant enzymes, catalysing the decomposition of potentially toxic lipid peroxides. Gpx activity and regulation of Gpx gene transcription has been shown previously to be complex with activity not necessarily mirrored by a corresponding elevation in gene transcription. By supplementing the diet of Vitamin E deficient rats with salicylic acid (1 g/kg diet), this study assessed effects of salicylic acid on cytosolic glutathione peroxidase activity in the colon. The ability of salicylic acid to modulate antioxidant enzymes in colon tissue may be an important mechanism in inhibiting colon cancer development.
Silva RL, etal., PLoS Negl Trop Dis. 2017 Mar 29;11(3):e0005486. doi: 10.1371/journal.pntd.0005486. eCollection 2017 Mar.
BACKGROUND: CD163, receptor for the haptoglobin-hemoglobin complex, is expressed on monocytes/macrophages and neutrophils. A soluble form of CD163 (sCD163) has been associated with the M2 macrophage phenotype, and M2 macrophages have been shown to down-modulate inflammatory responses. In
particular, previous studies have shown that M2 is closely associated with the most severe clinical presentation of leprosy (i.e. lepromatous leprosy (LL)), as well as tuberculosis. We hypothesized that sCD163 correlates with severity of diseases caused by intracellular pathogens. METHODOLOGY/PRINCIPAL FINDINGS: To assess this hypothesis, sCD163 levels were measured in the serum of leprosy and visceral leishmaniasis (VL) patients stratified by severity of the clinical presentation. sCD163 levels were significantly higher in patients with these diseases than those observed in healthy control individuals. Further analyses on infection and disease status of leprosy and VL patients revealed a clear association of sCD163 levels with clinical parameters of disease severity. In vitro culture assays revealed that Leishmania infection induced CD163 expression on the surface of both monocyte/macrophages and neutrophils, suggesting these cells as possible sources of sCD163. FACS analyses shows that the cells expressing CD163 produces both TNF-α and IL-4. CONCLUSIONS/SIGNIFICANCE: Taken together, our results reveal sCD163 as a potential biomarker of severity of diseases caused by intracellular pathogens M. leprae and Leishmania spp. and have a modulatory role, with a mix of an inflammatory property induced by TNF-α release, but that potentially induces an anti-inflammatory T cell response, related to IL-4 release.
Mutations in voltage-gated sodium channels expressed highly in the brain (SCN1A, SCN2A, SCN3A, and SCN8A) are responsible for an increasing number of epilepsy syndromes. In particular, mutations in the SCN3A gene, encoding the pore-forming Nav1.3 α subunit, have been identified in patients wit
h focal epilepsy. Biophysical characterization of epilepsy-associated SCN3A variants suggests that both gain- and loss-of-function SCN3A mutations may lead to increased seizure susceptibility. In this report, we identified a novel SCN3A variant (L247P) by whole exome sequencing of a child with focal epilepsy, developmental delay, and autonomic nervous system dysfunction. Voltage clamp analysis showed no detectable sodium current in a heterologous expression system expressing the SCN3A-L247P variant. Furthermore, cell surface biotinylation demonstrated a reduction in the amount of SCN3A-L247P at the cell surface, suggesting the SCN3A-L247P variant is a trafficking-deficient mutant. To further explore the possible clinical consequences of reduced SCN3A activity, we investigated the effect of a hypomorphic Scn3a allele (Scn3aHyp) on seizure susceptibility and behavior using a gene trap mouse line. Heterozygous Scn3a mutant mice (Scn3a+/Hyp) did not exhibit spontaneous seizures nor were they susceptible to hyperthermia-induced seizures. However, they displayed increased susceptibility to electroconvulsive (6Hz) and chemiconvulsive (flurothyl and kainic acid) induced seizures. Scn3a+/Hyp mice also exhibited deficits in locomotor activity and motor learning. Taken together, these results provide evidence that loss-of-function of SCN3A caused by reduced protein expression or deficient trafficking to the plasma membrane may contribute to increased seizure susceptibility.
Andrade FO, etal., Cells. 2023 Mar 21;12(6):961. doi: 10.3390/cells12060961.
Although multifactorial in origin, one of the most impactful consequences of social isolation is an increase in breast cancer mortality. How this happens is unknown, but many studies have shown that social isolation increases circulating inflammatory cytokines and impairs mitochondrial metabolism. U
sing a preclinical Sprague Dawley rat model of estrogen receptor-positive breast cancer, we investigated whether social isolation impairs the response to tamoxifen therapy and increases the risk of tumors emerging from dormancy, and thus their recurrence. We also studied which signaling pathways in the mammary glands may be affected by social isolation in tamoxifen treated rats, and whether an anti-inflammatory herbal mixture blocks the effects of social isolation. Social isolation increased the risk of dormant mammary tumor recurrence after tamoxifen therapy. The elevated recurrence risk was associated with changes in multiple signaling pathways including an upregulation of IL6/JAK/STAT3 signaling in the mammary glands and tumors and suppression of the mitochondrial oxidative phosphorylation (OXPHOS) pathway. In addition, social isolation increased the expression of receptor for advanced glycation end-products (RAGE), consistent with impaired insulin sensitivity and weight gain linked to social isolation. In socially isolated animals, the herbal product inhibited IL6/JAK/STAT3 signaling, upregulated OXPHOS signaling, suppressed the expression of RAGE ligands S100a8 and S100a9, and prevented the increase in recurrence of dormant mammary tumors. Increased breast cancer mortality among socially isolated survivors may be most effectively prevented by focusing on the period following the completion of hormone therapy using interventions that simultaneously target several different pathways including inflammatory and mitochondrial metabolism pathways.
BACKGROUND: Precision cancer medicine depends on defining distinct tumour subgroups using biomarkers that may occur at very modest frequencies. One such subgroup comprises patients with exceptionally mutated (ultramutated) cancers caused by mutations that impair DNA polymerase epsilon (PO
LE) proofreading. METHODS: We examined the association of POLE proofreading domain mutation with clinicopathological variables and immune response in colorectal cancers from clinical trials (VICTOR, QUASAR2, and PETACC-3) and colorectal cancer cohorts (Leiden University Medical Centre 1 and 2, Oslo 1 and 2, Bern, AMC-AJCC-II, and Epicolon-1). We subsequently investigated its association with prognosis in stage II/III colorectal cancer by Cox regression of pooled individual patient data from more than 4500 cases from these studies. FINDINGS: Pathogenic somatic POLE mutations were detected in 66 (1·0%) of 6517 colorectal cancers, and were mutually exclusive with mismatch repair deficiency (MMR-D) in the 6277 cases for whom both markers were determined (none of 66 vs 833 [13·4%] of 6211; p<0·0001). Compared with cases with wild-type POLE, cases with POLE mutations were younger at diagnosis (median 54·5 years vs 67·2 years; p<0·0001), were more frequently male (50 [75·8%] of 66 vs 3577 [55·5%] of 6445; p=0·0010), more frequently had right-sided tumour location (44 [68·8%] of 64 vs 2463 [39·8%] of 6193; p<0·0001), and were diagnosed at an earlier disease stage (p=0·006, χ2 test for trend). Compared with mismatch repair proficient (MMR-P) POLE wild-type tumours, POLE-mutant colorectal cancers displayed increased CD8+ lymphocyte infiltration and expression of cytotoxic T-cell markers and effector cytokines, similar in extent to that observed in immunogenic MMR-D cancers. Both POLE mutation and MMR-D were associated with significantly reduced risk of recurrence compared with MMR-P colorectal cancers in multivariable analysis (HR 0·34 [95% CI 0·11-0·76]; p=0·0060 and 0·72 [0·60-0·87]; p=0·00035), although the difference between the groups was not significant. INTERPRETATION: POLE proofreading domain mutations identify a subset of immunogenic colorectal cancers with excellent prognosis. This association underscores the importance of rare biomarkers in precision cancer medicine, but also raises important questions about how to identify and implement them in practice. FUNDING: Cancer Research UK, Academy of Medical Sciences, Health Foundation, EU, ERC, NIHR, Wellcome Trust, Dutch Cancer Society, Dutch Digestive Foundation.
Long-term l-3,4-dihydroxyphenylalanine (L-Dopa) treatment in Parkinson's disease leads to involuntary movements called dyskinesia, notably through an overexpression of immediate-early genes (IEG). Their rapid transcription involves the stalling of RNA polymerase II on IEG promoters, a mechanism tha
t critically depends on the presence of the negative elongation factor (NELF) protein complex. We here down-regulated the key NELF-E subunit using lentiviral vector delivery of a short hairpin RNA in the striatum of 6-hydroxydopamine lesioned rats. Such NELF-E reduced expression significantly attenuated the development of abnormal involuntary movements in response to chronic L-Dopa treatment. Effectiveness of silencing was demonstrated by the significant decrease in striatal FosB, ARC and Zif268 IEG expression. Repression of NELF-mediating RNA polymerase II stalling thus achieves both antidyskinetic and potentiation of antiparkinsonian L-Dopa effect, highlighting the role of transcriptional events in dyskinesia establishment, acute dyskinetic manifestation and in the therapeutic response to L-Dopa.
Satzer D, etal., BMC Neurosci. 2015 Nov 6;16:74. doi: 10.1186/s12868-015-0212-0.
BACKGROUND: T cells undergo autoimmunization following spinal cord injury (SCI) and play both protective and destructive roles during the recovery process. T cell-deficient athymic nude (AN) rats exhibit improved functional recovery when compared to immunocompetent Sprague-Dawley (SD) rat
s following spinal cord transection. METHODS: In the present study, we evaluated locomotor recovery in SD and AN rats following moderate spinal cord contusion. To explain variable locomotor outcome, we assessed whole-genome expression using RNA sequencing, in the acute (1 week post-injury) and chronic (8 weeks post-injury) phases of recovery. RESULTS: Athymic nude rats demonstrated greater locomotor function than SD rats only at 1 week post-injury, coinciding with peak T cell infiltration in immunocompetent rats. Genetic markers for T cells and helper T cells were acutely enriched in SD rats, while AN rats expressed genes for T(h)2 cells, cytotoxic T cells, NK cells, mast cells, IL-1a, and IL-6 at higher levels. Acute enrichment of cell death-related genes suggested that SD rats undergo secondary tissue damage from T cells. Additionally, SD rats exhibited increased acute expression of voltage-gated potassium (Kv) channel-related genes. However, AN rats demonstrated greater chronic expression of cell death-associated genes and less expression of axon-related genes. Immunostaining for macrophage markers revealed no T cell-dependent difference in the acute macrophage infiltrate. CONCLUSIONS: We put forth a model in which T cells facilitate early tissue damage, demyelination, and Kv channel dysregulation in SD rats following contusion SCI. However, compensatory features of the immune response in AN rats cause delayed tissue death and limit long-term recovery. T cell inhibition combined with other neuroprotective treatment may thus be a promising therapeutic avenue.
Hamada H, etal., J Immunol. 2009 Mar 15;182(6):3469-81.
We show here that IL-17-secreting CD4 T (Th)17 and CD8 T (Tc)17 effector cells are found in the lung following primary challenge with influenza A and that blocking Ab to IL-17 increases weight loss and reduces survival. Tc17 effectors can be generated in vitro using naive CD8 T cells from OT-I TCR-t
ransgenic mice. T cell numbers expand 20-fold and a majority secretes IL-17, but little IFN-gamma. Many of the IL-17-secreting cells also secrete TNF and some secrete IL-2. Tc17 are negative for granzyme B, perforin message, and cytolytic activity, in contrast to Tc1 effectors. Tc17 populations express message for orphan nuclear receptor gammat and FoxP3, but are negative for T-bet and GATA-3 transcription factors. The FoxP3-positive, IL-17-secreting and IFN-gamma-secreting cells represent three separate populations. The IFN-gamma-, granzyme B-, FoxP3-positive cells and cells positive for IL-22 come mainly from memory cells and decrease in number when generated from CD44(low) rather than unselected CD8 T cells. Cells of this unique subset of CD8 effector T cells expand greatly after transfer to naive recipients following challenge and can protect them against lethal influenza infection. Tc17 protection is accompanied by greater neutrophil influx into the lung than in Tc1-injected mice, and the protection afforded by Tc17 effectors is less perforin but more IFN-gamma dependent, implying that different mechanisms are involved.
RAR-related orphan receptor-gammat (ROR-gammat) directs differentiation of proinflammatory T helper 17 (TH17) cells and is a potential therapeutic target in chronic autoimmune and inflammatory diseases. However, ROR-gammat-dependent group 3 innate lymphoid cells ILC3s provide essential immunity and
tissue protection in the intestine, suggesting that targeting ROR-gammat could also result in impaired host defense after infection or enhanced tissue damage. Here, we demonstrate that transient chemical inhibition of ROR-gammat in mice selectively reduces cytokine production from TH17 but not ILCs in the context of intestinal infection with Citrobacter rodentium, resulting in preserved innate immunity. Temporal deletion of Rorc (encoding ROR-gammat) in mature ILCs also did not impair cytokine response in the steady state or during infection. Finally, pharmacologic inhibition of ROR-gammat provided therapeutic benefit in mouse models of intestinal inflammation and reduced the frequency of TH17 cells but not ILCs isolated from primary intestinal samples of individuals with inflammatory bowel disease (IBD). Collectively, these results reveal differential requirements for ROR-gammat in the maintenance of TH17 cell and ILC3 responses and suggest that transient inhibition of ROR-gammat is a safe and effective therapeutic approach during intestinal inflammation.
An essential component of microtubules, alpha-tubulin is also a multigene family in many species. An orthology-based nomenclature for this gene family has previously been difficult to assign due to incomplete genome builds and the high degree of sequence similarity between members of this family. Us
ing the current genome builds, sequence analysis of human, mouse, and rat alpha-tubulin genes has enabled an updated nomenclature to be generated. This revised nomenclature provides a unified language for the discussion of these genes in mammalian species; it has been approved by the gene nomenclature committees of the three species and is supported by researchers in the field.
Jagodic M, etal., Sci Transl Med. 2009 Dec 9;1(10):10ra21. doi: 10.1126/scitranslmed.3000278.
Multiple sclerosis, the most common cause of progressive neurological disability in young adults, is a chronic inflammatory disease. There is solid evidence for a genetic influence in multiple sclerosis, and deciphering the causative genes could reveal key pathways influencing the disease. A genome
region on rat chromosome 9 regulates experimental autoimmune encephalomyelitis, a model for multiple sclerosis. Using interval-specific congenic rat lines and association of single-nucleotide polymorphisms with inflammatory phenotypes, we localized the gene of influence to Vav1, which codes for a signal-transducing protein in leukocytes. Analysis of seven human cohorts (12,735 individuals) demonstrated an association of rs2546133-rs2617822 haplotypes in the first VAV1 intron with multiple sclerosis (CA: odds ratio, 1.18; CG: odds ratio, 0.86; TG: odds ratio, 0.90). The risk CA haplotype also predisposed for higher VAV1 messenger RNA expression. VAV1 expression was increased in individuals with multiple sclerosis and correlated with tumor necrosis factor and interferon-gamma expression in peripheral blood and cerebrospinal fluid cells. We conclude that VAV1 plays a central role in controlling central nervous system immune-mediated disease and proinflammatory cytokine production critical for disease pathogenesis.
INTRODUCTION: Leukotriene C4 synthase (LTC4S) gene -444A/C polymorphism has been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. The aim of this study was to investigate the association between the -444A/C polymorphism of LTC4S gen
e and asthma, asthma phenotypes (aspirin intolerant/tolerant asthma) and different characteristics of the patients. MATERIAL AND METHODS: We included 106 patients with asthma (60 with aspirin tolerant asthma - ATA, 46 with aspirin intolerant asthma - AIA) and 103 controls. All the subjects were genotyped for LTC4S-444 A/C by Real-Time PCR. We assessed the association of LTC4S promoter polymorphism with asthma and its phenotypes and with clinical and biological characteristics of asthmatic patients. RESULTS: We did not find a significant association between the studied polymorphism and asthma, but the minor allele tended to be more frequent in AIA patients. We found a significant association between the minor allele C and lower levels of serum total immunoglobulin E and eosinophils, suggesting a possible role of -444A/C LTC4S polymorphism as modulating factor of allergic inflammation in asthma. CONCLUSION: The results show that LTC4S -444A/C SNP is not associated with susceptibility to asthma in Romanian patients, but could influence asthma phenotype, namely aspirin intolerant asthma.
Horani A, etal., PLoS One. 2013 Aug 26;8(8):e72299. doi: 10.1371/journal.pone.0072299. eCollection 2013.
BACKGROUND: Primary ciliary dyskinesia (PCD) is a genetic disorder characterized by impaired ciliary function, leading to chronic sinopulmonary disease. The genetic causes of PCD are still evolving, while the diagnosis is often dependent on finding a ciliary ultrastructural abnormality an
d immotile cilia. Here we report a novel gene associated with PCD but without ciliary ultrastructural abnormalities evident by transmission electron microscopy, but with dyskinetic cilia beating. METHODS: Genetic linkage analysis was performed in a family with a PCD subject. Gene expression was studied in Chlamydomonas reinhardtii and human airway epithelial cells, using RNA assays and immunostaining. The phenotypic effects of candidate gene mutations were determined in primary culture human tracheobronchial epithelial cells transduced with gene targeted shRNA sequences. Video-microscopy was used to evaluate cilia motion. RESULTS: A single novel mutation in CCDC65, which created a termination codon at position 293, was identified in a subject with typical clinical features of PCD. CCDC65, an orthologue of the Chlamydomonas nexin-dynein regulatory complex protein DRC2, was localized to the cilia of normal nasal epithelial cells but was absent in those from the proband. CCDC65 expression was up-regulated during ciliogenesis in cultured airway epithelial cells, as was DRC2 in C. reinhardtii following deflagellation. Nasal epithelial cells from the affected individual and CCDC65-specific shRNA transduced normal airway epithelial cells had stiff and dyskinetic cilia beating patterns compared to control cells. Moreover, Gas8, a nexin-dynein regulatory complex component previously identified to associate with CCDC65, was absent in airway cells from the PCD subject and CCDC65-silenced cells. CONCLUSION: Mutation in CCDC65, a nexin-dynein regulatory complex member, resulted in a frameshift mutation and PCD. The affected individual had altered cilia beating patterns, and no detectable ultrastructural defects of the ciliary axoneme, emphasizing the role of the nexin-dynein regulatory complex and the limitations of certain methods for PCD diagnosis.
Cilia and flagella are microtubule-based structures nucleated by modified centrioles termed basal bodies. These biochemically complex organelles have more than 250 and 150 polypeptides, respectively. To identify the proteins involved in ciliary and basal body biogenesis and function, we undertook a
comparative genomics approach that subtracted the nonflagellated proteome of Arabidopsis from the shared proteome of the ciliated/flagellated organisms Chlamydomonas and human. We identified 688 genes that are present exclusively in organisms with flagella and basal bodies and validated these data through a series of in silico, in vitro, and in vivo studies. We then applied this resource to the study of human ciliation disorders and have identified BBS5, a novel gene for Bardet-Biedl syndrome. We show that this novel protein localizes to basal bodies in mouse and C. elegans, is under the regulatory control of daf-19, and is necessary for the generation of both cilia and flagella.
Wallmeier J, etal., Am J Hum Genet. 2019 Nov 7;105(5):1030-1039. doi: 10.1016/j.ajhg.2019.09.022. Epub 2019 Oct 17.
Hydrocephalus is one of the most prevalent form of developmental central nervous system (CNS) malformations. Cerebrospinal fluid (CSF) flow depends on both heartbeat and body movement. Furthermore, it has been shown that CSF flow within and across brain ventricles depends on cilia motility of the ep
endymal cells lining the brain ventricles, which play a crucial role to maintain patency of the narrow sites of CSF passage during brain formation in mice. Using whole-exome and whole-genome sequencing, we identified an autosomal-dominant cause of a distinct motile ciliopathy related to defective ciliogenesis of the ependymal cilia in six individuals. Heterozygous de novo mutations in FOXJ1, which encodes a well-known member of the forkhead transcription factors important for ciliogenesis of motile cilia, cause a motile ciliopathy that is characterized by hydrocephalus internus, chronic destructive airway disease, and randomization of left/right body asymmetry. Mutant respiratory epithelial cells are unable to generate a fluid flow and exhibit a reduced number of cilia per cell, as documented by high-speed video microscopy (HVMA), transmission electron microscopy (TEM), and immunofluorescence analysis (IF). TEM and IF demonstrate mislocalized basal bodies. In line with this finding, the focal adhesion protein PTK2 displays aberrant localization in the cytoplasm of the mutant respiratory epithelial cells.
AIMS: Five desmosomal genes have been recently implicated in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) but the clinical impact of genetics remains poorly understood. We wanted to address the potential impact of genotyping. METHODS AND RESULTS: Direct sequencing of the five g
enes (JUP, DSP, PKP2, DSG2, and DSC2) was performed in 135 unrelated patients with ARVD/C. We identified 41 different disease-causing mutations, including 28 novel ones, in 62 patients (46%). In addition, a genetic variant of unknown significance was identified in nine additional patients (7%). Distribution of genes was 31% (PKP2), 10% (DSG2), 4.5% (DSP), 1.5% (DSC2), and 0% (JUP). The presence of desmosomal mutations was not associated with familial context but was associated with young age, symptoms, electrical substrate, and extensive structural damage. When compared with other genes, DSG2 mutations were associated with more frequent left ventricular involvement (P = 0.006). Finally, complex genetic status with multiple mutations was identified in 4% of patients and was associated with more frequent sudden death (P = 0.047). CONCLUSION: This study supports the use of genetic testing as a new diagnostic tool in ARVC/D and also suggests a prognostic impact, as the severity of the disease appears different according to the underlying gene or the presence of multiple mutations.
Kotula E, etal., Cell Cycle. 2015;14(12):1961-72. doi: 10.1080/15384101.2015.1026522.
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) plays a major role in DNA damage signaling and repair and is also frequently overexpressed in tumor metastasis. We used isogenic cell lines expressing different levels of DNA-PKcs to investigate the role of DNA-PKcs in metastatic develo
pment. We found that DNA-PKcs participates in melanoma primary tumor and metastasis development by stimulating angiogenesis, migration and invasion. Comparison of conditioned medium content from DNA-PKcs-proficient and deficient cells reveals that DNA-PKcs controls secretion of at least 103 proteins (including 44 metastasis-associated with FBLN1, SERPINA3, MMP-8, HSPG2 and the inhibitors of matrix metalloproteinases, such as alpha-2M and TIMP-2). High throughput analysis of secretomes, proteomes and transcriptomes, indicate that DNA-PKcs regulates the secretion of 85 proteins without affecting their gene expression. Our data demonstrate that DNA-PKcs has a pro-metastatic activity via the modification of the tumor microenvironment. This study shows for the first time a direct link between DNA damage repair and cancer metastasis and highlights the importance of DNA-PKcs as a potential target for anti-metastatic treatment.
Maroto JP, etal., J Clin Oncol. 2011 May 1;29(13):1750-6. doi: 10.1200/JCO.2010.29.2235. Epub 2011 Mar 28.
PURPOSE: Pneumonitis has occurred in patients treated with inhibitors of the mammalian target of rapamycin (mTOR). In a phase III study of patients with previously untreated, poor-prognosis, advanced renal cell carcinoma (ARCC), the mTOR inhibitor temsirolimus improved survival compared with interfe
ron. We performed a retrospective, independent, blinded radiographic review of chest computed tomography (CT) images of patients in this study to characterize temsirolimus-related pneumonitis. PATIENTS AND METHODS: Patients were treated with intravenous temsirolimus 25 mg once weekly or subcutaneous interferon alfa 3 million units, with an increase to 18 million units, thrice weekly. Drug-related pneumonitis was identified based on sequential chest CT images, required every 8 weeks, showing changes consistent with pneumonitis and not pneumonia (infection) or disease progression as correlated with clinical data. Cumulative probability of drug-related pneumonitis was estimated using the Kaplan-Meier method. RESULTS: Eight (6%) of 138 and 52 (29%) of 178 evaluable patients on interferon and temsirolimus treatment, respectively, developed radiographically identified drug-related pneumonitis. Time to onset of pneumonitis was significantly shorter on the temsirolimus arm than on the interferon arm (log-rank P < .001). Estimated cumulative probability of pneumonitis at 8 and 16 weeks from first dose was 21% and 31%, respectively, on the temsirolimus arm and 6% and 8%, respectively, on the interferon arm. Respiratory symptoms were observed around time of onset of radiographically diagnosed temsirolimus-related pneumonitis in 16 (31%) of 52 patients. CONCLUSION: Patients with ARCC receiving temsirolimus should be monitored closely for development of pneumonitis, and their management should be altered if clinical symptoms appear.
Andre B, etal., Biochem Biophys Res Commun. 2011 Jul 22;411(1):175-9. doi: 10.1016/j.bbrc.2011.06.125. Epub 2011 Jun 25.
The rapid turnover rate of hyaluronan (HA), the major unbranched glycosaminoglycan of the extracellular matrix, is dependent on hyaluronidases. One of them, hyaluronidase-2 (Hyal2), degrades HA into smaller fragments endowed with specific biological activities such as inflammation and angiogenesis.
Yet the cellular environment of Hyal2, a purported glycosylphosphatidylinositol (GPI)-anchored protein, remains uncertain. We have examined the membrane association of Hyal2 in MDA-MB231 cancer cells where it is highly expressed and in COS-7 cells transfected with native or fluorescent Hyal2 constructs. In both cell types, Hyal2 was strongly associated with cell membrane fractions from which it could be extracted using a Triton X-114 treatment (hydrophobic phase) but not an osmotic shock or an alkaline carbonate solution. Treatment of membrane preparations with phosphatidylinositol-specific phospholipase C released immunoreactive Hyal2 into the aqueous phase, confirming the protein is attached to the membrane through a functional GPI anchor. Hyal2 transfected in COS-7 cells was associated with detergent-resistant, cholesterol-rich membranes known as lipid rafts. The cellular immunofluorescent pattern of Hyal2 was conditioned by the presence of a GPI anchor. In summary, the strong membrane association of Hyal2 through its GPI anchor demonstrated in this study using biochemical methods suggests that the main activity of this enzyme is located at the level of the plasma membrane in close contact with the pericellular HA-rich glycocalyx, the extracellular matrix, or possibly endocytic vesicles.
Van Waes V, etal., Eur J Neurosci. 2006 Aug;24(4):1193-200. doi: 10.1111/j.1460-9568.2006.04973.x. Epub 2006 Aug 21.
The period of adolescence and environmental factors, such as stress, are important in determining ethanol vulnerability in both humans and rats. Ethanol is a powerful activator of the hypothalamic-pituitary-adrenal (HPA) axis but attenuated responses of the HPA axis to ethanol have been described in
populations with a high risk of ethanol abuse. In rats, prenatal stress leads to prolonged stress-induced corticosterone secretion and increases the vulnerability to drugs of abuse, such as amphetamine and nicotine in adulthood and 3,4-methylenedioxymethamphetamine in adolescent rats. The aim of the present study was to assess the impact of a prenatal stress on HPA axis responsiveness to a moderate dose of ethanol (1.5 g/kg i.p.) in adolescent male rats (28 days old). The parameters evaluated were plasma adrenocorticotropic hormone, plasma corticosterone and mRNA expression of HPA axis central markers (mineralocorticoid receptor, glucocorticoid receptor, corticotropin-releasing hormone and pro-opiomelanocortin). Contrary to prior expectations, our results demonstrate that prenatal stress blunts the HPA axis responsiveness to a moderate dose of ethanol in adolescent rats in spite of similar blood ethanol levels. These data suggest that prenatal stress may have the opposite effect on the response to stress depending on the attributes of the stressor stimulus. They thus raise questions about the possible impact of prenatal stress on the further development of ethanol vulnerability.
Ortiz LA, etal., Proc Natl Acad Sci U S A. 2007 Jun 26;104(26):11002-7. Epub 2007 Jun 14.
Mesenchymal stem cells (MSCs) have been exploited as cellular vectors to treat a wide array of diseases but the mechanisms responsible for their therapeutic effect remain indeterminate. Previously, we reported that MSCs inhibit bleomycin (BLM)-induced inflammation and fibrosis within the lungs of mi
ce. Interrogation of the MSC transcriptome identified interleukin 1 receptor antagonist (IL1RN) as a potential mediator of this effect. Fractionation studies indicated that MSCs are the principal source of IL1RN in murine bone marrow and that its expression is restricted to a unique subpopulation of cells. Moreover, MSC-conditioned media was shown to block proliferation of an IL-1alpha-dependent T cell line and inhibit production of TNF-alpha by activated macrophages in vitro. Studies conducted in mice revealed that MSC administration was more effective than recombinant IL1RN delivered via adenoviral infection or osmotic pumps in inhibiting BLM-induced increases in TNF-alpha, IL-1alpha, and IL1RN mRNA in lung, IL1RN protein in bronchoalveolar lavage (BAL) fluid, and trafficking of lymphocytes and neutrophils into the lung. Therefore, MSCs protect lung tissue from BLM-induced injury by blocking TNF-alpha and IL-1, two fundamental proinflammatory cytokines in lung. Identification of IL1RN-expressing human MSC subpopulations may provide a novel cellular vector for treating chronic inflammatory diseases in humans.
Very recently, mutations in the TRPM4 gene have been identified in four pedigrees as the cause of an autosomal dominant form of cardiac conduction disease. To determine the role of TRPM4 gene variations, the relative frequency of TRPM4 mutations and associated phenotypes was assessed in a cohort of
160 unrelated patients with various types of inherited cardiac arrhythmic syndromes. In eight probands with atrioventricular block or right bundle branch block--five familial cases and three sporadic cases--a total of six novel and two published TRPM4 mutations were identified. In patients with sinus node dysfunction, Brugada syndrome, or long-QT syndrome, no mutations were found. The novel mutations include six amino acid substitutions and appeared randomly distributed through predicted TRPM4 protein. In addition, eight polymorphic sites including two in-frame deletions were found. Mutations separated from polymorphisms by absence in control individuals and familial cosegregation in some families. In summary, TRPM4 gene mutations appear to play a major role in cardiac conduction disease but not for other related syndromes so far. The phenotypes are variable and clearly suggestive of additional factors modulating the disease phenotype in some patients.
Horani A, etal., Am J Hum Genet. 2012 Oct 5;91(4):685-93. doi: 10.1016/j.ajhg.2012.08.022.
Motile cilia are essential components of the mucociliary escalator and are central to respiratory-tract host defenses. Abnormalities in these evolutionarily conserved organelles cause primary ciliary dyskinesia (PCD). Despite recent strides characterizing the ciliome and sensory ciliopathies through
exploration of the phenotype-genotype associations in model organisms, the genetic bases of most cases of PCD remain elusive. We identified nine related subjects with PCD from geographically dispersed Amish communities and performed exome sequencing of two affected individuals and their unaffected parents. A single autosomal-recessive nonsynonymous missense mutation was identified in HEATR2, an uncharacterized gene that belongs to a family not previously associated with ciliary assembly or function. Airway epithelial cells isolated from PCD-affected individuals had markedly reduced HEATR2 levels, absent dynein arms, and loss of ciliary beating. MicroRNA-mediated silencing of the orthologous gene in Chlamydomonas reinhardtii resulted in absent outer dynein arms, reduced flagellar beat frequency, and decreased cell velocity. These findings were recapitulated by small hairpin RNA-mediated knockdown of HEATR2 in airway epithelial cells from unaffected donors. Moreover, immunohistochemistry studies in human airway epithelial cells showed that HEATR2 was localized to the cytoplasm and not in cilia, which suggests a role in either dynein arm transport or assembly. The identification of HEATR2 contributes to the growing number of genes associated with PCD identified in both individuals and model organisms and shows that exome sequencing in family studies facilitates the discovery of novel disease-causing gene mutations.
Carapito R, etal., Am J Hum Genet. 2019 Feb 7;104(2):319-330. doi: 10.1016/j.ajhg.2018.12.007. Epub 2019 Jan 10.
ZMIZ1 is a coactivator of several transcription factors, including p53, the androgen receptor, and NOTCH1. Here, we report 19 subjects with intellectual disability and developmental delay carrying variants in ZMIZ1. The associated features include growth failure, feeding difficulties, microcephaly,
facial dysmorphism, and various other congenital malformations. Of these 19, 14 unrelated subjects carried de novo heterozygous single-nucleotide variants (SNVs) or single-base insertions/deletions, 3 siblings harbored a heterozygous single-base insertion, and 2 subjects had a balanced translocation disrupting ZMIZ1 or involving a regulatory region of ZMIZ1. In total, we identified 13 point mutations that affect key protein regions, including a SUMO acceptor site, a central disordered alanine-rich motif, a proline-rich domain, and a transactivation domain. All identified variants were absent from all available exome and genome databases. In vitro, ZMIZ1 showed impaired coactivation of the androgen receptor. In vivo, overexpression of ZMIZ1 mutant alleles in developing mouse brains using in utero electroporation resulted in abnormal pyramidal neuron morphology, polarization, and positioning, underscoring the importance of ZMIZ1 in neural development and supporting mutations in ZMIZ1 as the cause of a rare neurodevelopmental syndrome.
Multiple sclerosis (MS) is a chronic relapsing-remitting inflammatory disease of the central nervous system characterized by oligodendrocyte damage, demyelination and neuronal death. Genetic association studies have shown a 2-fold or greater prevalence of the HLA-DRB1*1501 allele in the MS populati
on compared with normal Caucasians. In discovery cohorts of Australasian patients with MS (total 2941 patients and 3008 controls), we examined the associations of 12 functional polymorphisms of P2X7, a microglial/macrophage receptor with proinflammatory effects when activated by extracellular adenosine triphosphate (ATP). In discovery cohorts, rs28360457, coding for Arg307Gln was associated with MS and combined analysis showed a 2-fold lower minor allele frequency compared with controls (1.11% for MS and 2.15% for controls, P = 0.0000071). Replication analysis of four independent European MS case-control cohorts (total 2140 cases and 2634 controls) confirmed this association [odds ratio (OR) = 0.69, P = 0.026]. A meta-analysis of all Australasian and European cohorts indicated that Arg307Gln confers a 1.8-fold protective effect on MS risk (OR = 0.57, P = 0.0000024). Fresh human monocytes heterozygous for Arg307Gln have >85% loss of 'pore' function of the P2X7 receptor measured by ATP-induced ethidium uptake. Analysis shows Arg307Gln always occurred with 270His suggesting a single 307Gln-270His haplotype that confers dominant negative effects on P2X7 function and protection against MS. Modeling based on the homologous zP2X4 receptor showed Arg307 is located in a region rich in basic residues located only 12 A from the ligand binding site. Our data show the protective effect against MS of a rare genetic variant of P2RX7 with heterozygotes showing near absent proinflammatory 'pore' function.
Alsafadi S, etal., Nat Commun. 2016 Feb 4;7:10615. doi: 10.1038/ncomms10615.
Hotspot mutations in the spliceosome gene SF3B1 are reported in approximately 20% of uveal melanomas. SF3B1 is involved in 3'-splice site (3'ss) recognition during RNA splicing; however, the molecular mechanisms of its mutation have remained unclear. Here we show, using RNA-Seq analyses of uveal mel
anoma, that the SF3B1(R625/K666) mutation results in deregulated splicing at a subset of junctions, mostly by the use of alternative 3'ss. Modelling the differential junctions in SF3B1(WT) and SF3B1(R625/K666) cell lines demonstrates that the deregulated splice pattern strictly depends on SF3B1 status and on the 3'ss-sequence context. SF3B1(WT) knockdown or overexpression do not reproduce the SF3B1(R625/K666) splice pattern, qualifying SF3B1(R625/K666) as change-of-function mutants. Mutagenesis of predicted branchpoints reveals that the SF3B1(R625/K666)-promoted splice pattern is a direct result of alternative branchpoint usage. Altogether, this study provides a better understanding of the mechanisms underlying splicing alterations induced by mutant SF3B1 in cancer, and reveals a role for alternative branchpoints in disease.
Cajal-Retzius (CR) cells are essential for cortical development and lamination. These pioneer neurons arise from distinct progenitor sources, including the cortical hem and the ventral pallium at pallium-subpallium boundary (PSB). CXCR4, the canonical receptor for the chemokine CXCL12, controls the
superficial location of hem-derived CR cells. However, recent studies showed that CXCR7, a second CXCL12 receptor, is also expressed in CR cells at early developmental stages. We thus investigated the role of CXCR7 during CR cell development using multiple loss-of-function approaches. Cxcr7 gene inactivation led to aberrant localization of Reelin-positive cells within the pallium. In addition, Cxcr7(-/-) mice were characterized by significant accumulation of ectopic CR cells in the lateral part of the dorsal pallium compared with Cxcr4 knockout mice. Loss-of-function approaches, using either gene targeting or pharmacological receptor inhibition, reveal that CXCR7 and CXCR4 act both in CR positioning. Finally, conditional Cxcr7 deletion in cells derived from Dbx1-expressing progenitors indicates an essential role of CXCR7 in controlling the positioning of a subpopulation of PSB-derived CR cells. Our data demonstrate that CXCR7 has a role in the positioning of hem and PSB-derived CR cells, CXCL12 regulating CR cell subpial localization through the combined action of CXCR4 and CXCR7.
Preeclampsia is a pregnancy-specific disorder associated with hyperlipidemia. Liver X receptor (LXR) alpha and LXRbeta are key regulators of lipid homeostasis. In the current study, we investigated expression of LXRalpha, LXRbeta and their target genes in human term placenta, decidua and subcutaneou
s adipose tissue from pregnancies complicated by preeclampsia. Furthermore, we analyzed the protein levels of LXRalpha and LXRbeta in placenta. We also analyzed lipid concentrations in term placental tissue. Gene expression of LXRalpha, LXRbeta and fatty acid transporter CD36 was significantly decreased in placental tissues, while increased expression was observed for LXRalpha in adipose tissue, from pregnancies complicated by preeclampsia. The placental protein level of LXRbeta was reduced, and there was a positive correlation between placental LXRbeta mRNA expression and placental free fatty acids in preeclampsia. Our results suggest a possible role for LXRbeta as a transcriptional regulator in preeclampsia.
BACKGROUND: Immunodeficient mice are invaluable tools to analyze the long-term effects of potentially immunogenic molecules in the absence of adaptive immune responses. Nevertheless, there are models and experimental situations that would beneficiate of larger immunodeficient recipients.
Rats are ideally suited to perform experiments in which larger size is needed and are still a small animal model suitable for rodent facilities. Additionally, rats reproduce certain human diseases better than mice, such as ankylosing spondylitis and Duchenne disease and these disease models would greatly benefit of immunodeficient rats to test different immunogenic treatments. METHODS: We describe the generation of Il2rg-deficient rats and their crossing with previously described Rag1-deficient rats to generate double-mutant RRG animals. RESULTS: As compared to Rag1-deficient rats, Il2rg-deficient rats were more immunodeficient since partially lacked not only T and B cells but also NK cells. RRG animals showed a more profound immunossuppressed phenotype since they displayed undetectable levels of T, B and NK cells. Similarly, all immunoglobulin isotypes in sera were decreased in Rag1 or Il2rg-deficient rats and undetectable in RRG animals. Rag1 or Il2rg-deficient rats rejected allogeneic skin transplants and human tumors whereas RRG animals not only accepted allogeneic rat skin but also xenogeneic human tumors, skin and hepatocytes. Immune humanization of RRG animals was unsuccessful. CONCLUSION: Thus, immunodeficient RRG animals are useful recipients for long term studies in which immune responses could be an obstacle, including tissue humanization of different tissues.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Yamada M, etal., Nature 2001 Mar 8;410(6825):207-12.
Members of the muscarinic acetylcholine receptor family (M1-M5) have central roles in the regulation of many fundamental physiological functions. Identifying the specific receptor subtype(s) that mediate the diverse muscarinic actions of acetylcholine is of considerable therapeutic interest, but has
proved difficult primarily because of a lack of subtype-selective ligands. Here we show that mice deficient in the M3 muscarinic receptor (M3R-/- mice) display a significant decrease in food intake, reduced body weight and peripheral fat deposits, and very low levels of serum leptin and insulin. Paradoxically, hypothalamic messenger RNA levels of melanin-concentrating hormone (MCH), which are normally upregulated in fasted animals leading to an increase in food intake, are significantly reduced in M3R-/- mice. Intra-cerebroventricular injection studies show that an agouti-related peptide analogue lacked orexigenic (appetite-stimulating) activity in M3R-/- mice. However, M3R-/- mice remained responsive to the orexigenic effects of MCH. Our data indicate that there may be a cholinergic pathway that involves M3-receptor-mediated facilitation of food intake at a site downstream of the hypothalamic leptin/melanocortin system and upstream of the MCH system.
Pesant M, etal., Cardiovasc Res. 2006 Feb 1;69(2):440-9. Epub 2005 Dec 6.
OBJECTIVE: Activation of peroxisome proliferator-activated receptor alpha (PPARalpha) and PPARgamma plays beneficial roles in cardiovascular disorders such as atherosclerosis and heart reperfusion. Although PPARalpha and gamma have been documented to reduce oxidative stress in the vasculature and th
e heart, the role of PPARdelta remains poorly studied. METHODS AND RESULTS: We focused on PPARdelta function in the regulation of oxidative stress-induced apoptosis in the rat cardiomyoblast cell line H9c2. Using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), we showed that PPARdelta is the predominantly expressed isotype whereas PPARalpha was weakly detected. By performing cell viability assays, we also showed that the selective PPARdelta agonist GW501516 protected cells from H(2)O(2)-induced cell death. The protective effect of GW501516 was due to an inhibition of H(2)O(2)-triggered apoptosis as shown by annexin-V labeling, DNA fragmentation analysis, and caspase-3 activity measurement. We demonstrated by transient transfection of a dominant negative mutant of PPARdelta that the protection induced by GW501516 was totally dependent on PPARdelta. Semi-quantitative RT-PCR and Western blotting analysis demonstrated that GW501516 treatment upregulated catalase. Moreover, forced overexpression of catalase inhibited H(2)O(2)-triggered apoptosis, as evidenced by annexin-V labeling. CONCLUSION: Taken together, our results account for an important role of PPARdelta in inhibiting the onset of oxidative stress-induced apoptosis in H9c2 cells. PPARdelta appears to be a new therapeutic target for the regulation of heart reperfusion-associated oxidative stress and stimulation of enzymatic antioxidative defences.
Daniel JM, etal., Arterioscler Thromb Vasc Biol. 2016 Feb;36(2):317-27. doi: 10.1161/ATVBAHA.115.305974. Epub 2015 Dec 10.
OBJECTIVE: Regulator of G-protein signaling 5 (RGS5) is abundantly expressed in vascular smooth muscle cells (SMCs) and inhibits G-protein signaling by enhancing the guanosine triphosphate-hydrolyzing activity of Galpha-subunits. In the present study, we investigated the effects of RGS5 on vascular
SMC function in vitro and neointima formation after wire-induced injury in mice and determined the underlying mechanisms. APPROACH AND RESULTS: We found a robust expression of RGS5 in native arteries of C57BL/6 mice and a highly significant downregulation within neointimal lesions 10 and 21 days after vascular injury as assessed by quantitative polymerase chain reaction, immunoblotting, and immunohistochemistry. In vitro, RGS5 was found significantly downregulated after mitogenic stimulation of human coronary artery SMCs. To restore RGS5 levels, SMCs were transduced with adenoviral vectors encoding wild-type RGS5 or a nondegradable mutant. RGS5-WT and, even more prominently, the C2A-RGS5 mutant prevented SMC proliferation and migration. In contrast, the siRNA-mediated knockdown of RGS5 significantly augmented SMC proliferation. Following overexpression of RGS5, fluorescence-activated cell sorting analysis of propidium iodide-stained cells indicated cell cycle arrest in G0/G1 phase. Mechanistically, inhibition of the phosphorylation of the extracellular signal-regulated kinase 1/2 and mitogen-activated protein kinase downstream signaling was shown to be responsible for the anti-proliferative effect of RGS5. Following wire-induced injury of the femoral artery in C57BL/6 mice, adenoviral-mediated overexpression of RGS5-WT or C2A-RGS5 significantly reduced SMC proliferation and neointima formation in vivo. CONCLUSIONS: Downregulation of RGS5 is an important prerequisite for SMC proliferation in vitro and in vivo. Therefore, reconstitution of RGS5 levels represents a promising therapeutic option to prevent vascular remodeling processes.
Spermatogenesis consists broadly of three phases: proliferation of diploid germ cells, meiosis, and finally extensive differentiation of the haploid cells into effective delivery vehicles for the paternal genome. Despite detailed characterization of many haploid developmental steps leading to sperm,
only fragmentary information exists on the control of gene expression underlying these processes. Here we report that the RFX2 transcription factor is a master regulator of genes required for the haploid phase. A targeted mutation of Rfx2 was created in mice. Rfx2-/- mice are perfectly viable but show complete male sterility. Spermatogenesis appears to progress unperturbed through meiosis. However, haploid cells undergo a complete arrest in spermatid development just prior to spermatid elongation. Arrested cells show altered Golgi apparatus organization, leading to a deficit in the generation of a spreading acrosomal cap from proacrosomal vesicles. Arrested cells ultimately merge to form giant multinucleated cells released to the epididymis. Spermatids also completely fail to form the flagellar axoneme. RNA-Seq analysis and ChIP-Seq analysis identified 139 genes directly controlled by RFX2 during spermiogenesis. Gene ontology analysis revealed that genes required for cilium function are specifically enriched in down- and upregulated genes showing that RFX2 allows precise temporal expression of ciliary genes. Several genes required for cell adhesion and cytoskeleton remodeling are also downregulated. Comparison of RFX2-regulated genes with those controlled by other major transcriptional regulators of spermiogenesis showed that each controls independent gene sets. Altogether, these observations show that RFX2 plays a major and specific function in spermiogenesis.
Increased platelet reactivity has been implicated in the vascular complications of myeloproliferative diseases and diabetes mellitus. The mechanisms of platelet hyperresponsiveness have not been fully explained. Expression of CD36 or fatty acid translocase (FAT) and its role in arachidonic acid (AA
) uptake by platelets were examined in subjects with myeloproliferative disorders (MPD), those with non-insulin-dependent diabetes mellitus (NIDDM), and in normal, healthy, age-matched controls. Surface expression of CD36 on platelet membranes was increased in MPD (10.94 +/- 0.76 pmol/mg protein) compared with normal controls (6.94 +/- 0.48 pmol/mg protein), p < 0.001. Total platelet content of CD36 was also significantly higher (32.1 +/- 0.61 pmol/mg protein, p < 0.01) compared with those in sex and age matched normal controls (25.7 +/- 1.09 pmol/mg protein). In contrast, platelet surface expression of CD36 in NIDDM (6.5 +/- 0.56 pmol/mg protein) was not significantly different from those of normal controls despite higher total content of CD36 (32.8 +/- 1.2, pmol/mg protein, p < 0 .01). Intact MPD platelets bound significantly more arachidonic acid (AA) (1.53 +/- 0.16 nmol/mg protein, p < 0.05), compared with controls (1.12 +/- 0.07 nmol/mg protein) or NIDDM subjects (1.16 +/- 0.16 nmol/mg protein). The capacity of MPD platelet membranes to bind 14C-AA was also increased (1.72 +/- 0.25 nmol/mg protein, p < 0.05) compared with that of controls (1.62 +/- 0.05 nmol/mg protein) and of NIDDM (1.22 +/- 0.08 nmol/mg protein). This is consistent with higher surface expression of CD36 in MPD platelets. Membrane fatty acid analysis indicated that the % of AA in platelet phospholipids was significantly lower in MPD (3.15 +/- 0.81%) compared with the controls (5.62 +/- 1.7%, p < 0.05. The AA content of diabetic platelets (4.82 +/- 1.1%) was not significantly different from normal controls. In summary, both total and surface expression of CD36 are increased in MPD, consistent with an enhanced capacity for uptake of AA by platelets. Increased expression of CD36 in platelets may play a role in the vaso-occlusive manifestations of MPD.
A few animal models of Duchenne muscular dystrophy (DMD) are available, large ones such as pigs or dogs being expensive and difficult to handle. Mdx (X-linked muscular dystrophy) mice only partially mimic the human disease, with limited chronic muscular lesions and muscle weakness. Their small size
also imposes limitations on analyses. A rat model could represent a useful alternative since rats are small animals but 10 times bigger than mice and could better reflect the lesions and functional abnormalities observed in DMD patients. Two lines of Dmd mutated-rats (Dmdmdx) were generated using TALENs targeting exon 23. Muscles of animals of both lines showed undetectable levels of dystrophin by western blot and less than 5% of dystrophin positive fibers by immunohistochemistry. At 3 months, limb and diaphragm muscles from Dmdmdx rats displayed severe necrosis and regeneration. At 7 months, these muscles also showed severe fibrosis and some adipose tissue infiltration. Dmdmdx rats showed significant reduction in muscle strength and a decrease in spontaneous motor activity. Furthermore, heart morphology was indicative of dilated cardiomyopathy associated histologically with necrotic and fibrotic changes. Echocardiography showed significant concentric remodeling and alteration of diastolic function. In conclusion, Dmdmdx rats represent a new faithful small animal model of DMD.
Paulmyer-Lacroix O, etal., Eur J Endocrinol. 2006 Jul;155(1):177-85.
OBJECTIVE: Adrenomedullin (AM), a potent vasodilatator and antioxidative peptide, was shown recently to be expressed by adipose tissue. The aim of our study was to investigate the precise localization of AM within human adipose tissue, and to examine AM regulation in obesity. DESIGN: Subcutaneous (S
C) and omental (OM) adipose tissues from 9 lean and 13 obese women were profiled for AM expression changes. Preadipocytes from human adipose tissue were isolated and differentiated under defined adipogenic conditions. METHODS: AM expression was analyzed by immunohistochemistry, in situ hybridization and quantitative RT-PCR. RESULTS: A strong AM expression was observed in vessel walls, stromal cell clusters and isolated stromal cells, some of them being CD 68 positive, whereas mature adipocytes were not labeled. Calcitonin receptor-like receptor and receptor activity-modifying proteins (RAMP) 2 and RAMP 3 were expressed in vessel walls. In vitro, preadipocytes of early differentiation stages spontaneously secreted AM. No difference in AM localization was found between SC and OM adipose tissue. AM levels in SC tissue did not differ between lean and obese subjects. By contrast, AM levels in OM tissue were significantly higher in obese as compared with lean women. Moreover, we found a positive relationship between OM AM and tumor necrosis factor alpha mRNA levels and AM-immunoreactive area in OM tissue followed the features of the metabolic syndrome. CONCLUSION: Stromal cells from human adipose tissue, including macrophages, produce AM. Its synthesis increased in the OM territory during obesity and paralleled the features of the metabolic syndrome. Therefore, AM should be considered as a new member of the adipokine family.
Schlegel A, etal., J Hepatol. 2013 Nov;59(5):984-91. doi: 10.1016/j.jhep.2013.06.022. Epub 2013 Jun 29.
BACKGROUND & AIMS: The use of livers from donors after cardiac arrest (DCD) is increasing in many countries to overcome organ shortage. Due to additional warm ischemia before preservation, those grafts are at higher risk of failure and bile duct injury. Several competing rescue strategies by machine
perfusion techniques have been developed with, however, unclear effects on biliary injury. We analyze the impact of an end-ischemic Hypothermic Oxygenated PErfusion (HOPE) approach applied only through the portal vein for 1h before graft implantation. METHODS: Rat livers were subjected to 30-min in situ warm ischemia, followed by subsequent 4-h cold storage, mimicking DCD-organ procurement and conventional organ transport. Livers in the HOPE group underwent also passive cold storage for 4h, but were subsequently machine perfused for 1h before implantation. Outcome was tested by liver transplantation (LT) at 12h after implantation (n=10 each group) and after 4 weeks (n=10 each group), focusing on early reperfusion injury, immune response, and later intrahepatic biliary injury. RESULTS: All animals survived after LT. However, reperfusion injury was significantly decreased by HOPE treatment as tested by hepatocyte injury, Kupffer cell activation, and endothelial cell activation. Recipients receiving non-perfused DCD livers disclosed less body weight gain, increased bilirubin, and severe intrahepatic biliary fibrosis. In contrast, HOPE treated DCD livers were protected from biliary injury, as detected by cholestasis parameter and histology. CONCLUSIONS: We demonstrate in a DCD liver transplant model that end-ischemic hypothermic oxygenated perfusion is a powerful strategy for protection against biliary injury.
The major goal of this study was to evaluate the effects of tumor necrosis factor-alpha (TNF-alpha), delivered as pGL1-TNF-alpha, on hematological variables, as well as C6 tumor growth in athymic mice treated with and without radiation. pGL1-TNF-alpha was administered intratumorally at low to high d
oses (15, 150 and 450 microg) in all three phases of this study. In phase A, pGL1-TNF-alpha expression within tumors was dose dependent and transient, with highest levels seen at 18 h after injection, whereas no TNF-alpha protein was detected in plasma. Low erythrocyte counts, hemoglobin, and hematocrit were associated with tumor presence, but the reduction in these variables was most striking in the group receiving 450 microg of pGL1-TNF-alpha, the group that also exhibited thrombocytopenia at 72 h. In phase B, treatment with pGL1-TNF-alpha at 15 or 150 microg resulted in the greatest degree of splenomegaly, increased spontaneous blastogenesis by splenocytes, and high leukocyte and lymphocyte numbers in the spleen. In these same two groups, flow cytometry analyses of spleen cells showed that high levels of natural killer (panNK+) cells, B (CD19+) lymphocytes, and cells expressing the CD71 and CD25 activation markers were present (p < 0.05). An enhancing effect was also noted in some of the measurements with parental plasmid p WS4 and tumor presence. In phase C, the slowest tumor progression was observed in the groups receiving 15 and 150 microg pGL1-TNF-alpha together with radiation; tumor volumes were 51 and 43% smaller, respectively, than for PBS-injected controls by the end of the study. Collectively, these results show that localized treatment with pGL1-TNF-alpha is hematologically nontoxic at low doses and support the premise that activation of lymphocytes may contribute to the antitumor effects of radiation against a highly aggressive brain tumor.
Demuth I, etal., Neurogenetics. 2011 Nov;12(4):273-82. doi: 10.1007/s10048-011-0299-0. Epub 2011 Oct 2.
Ataxia telangiectasia (AT) is an autosomal recessive disorder characterized by cerebellar degeneration, immunodeficiency, oculocutaneous telangiectasias, chromosomal instability, radiosensitivity, and cancer predisposition. The gene mutated in the patients, ATM, encodes a member of the phosphatidyli
nositol 3-kinase family proteins. The ATM protein has a key role in the cellular response to DNA damage. Truncating and splice site mutations in ATM have been found in most patients with the classical AT phenotype. Here we report of our extensive ATM mutation screening on 25 AT patients from 19 families of different ethnic origin. Previously unknown mutations were identified in six patients including a new homozygous missense mutation, c.8110T>C (p.Cys2704Arg), in a severely affected patient. Comprehensive clinical data are presented for all patients described here along with data on ATM function generated by analysis of cell lines established from a subset of the patients.
Golec M, etal., Ann Agric Environ Med. 2009 Dec;16(2):289-97.
The cathelicidin LL-37 is an antimicrobial and lipopolysaccharide neutralizing peptide, possessing pro-inflammatory, tissue repair and remodeling activities. Recent reports indicate that the progression of COPD might be connected with increased levels of LL-37. The numerous experimental data show th
e potential role of LL-37 in the response to the exposure to organic dust (containing lipopolysaccharide and microorganisms) which is one of the major COPD causative factors. This work strives to further prove the role of LL-37 in the development of COPD. A cross-sectional study was conducted in 30 farmers in the early stages of COPD according to GOLD, 36 healthy farmers and 16 healthy urban dwellers. Collection of induced-sputum samples and lung function testing were conducted before and after work. The quantification of the LL-37 in sputum samples was performed by mass spectrometry and radioisotope techniques. Levels of granzymes A and B, IL-8, IFN-gamma and TGF-beta1 in sputum were measured by ELISA technique. Statistical analysis was conducted by Kruskal-Wallis and Mann-Whitney U tests. Significantly higher levels of LL-37 were observed in sputum samples from farmers with COPD compared to healthy individuals. The concentration of LL-37 in sputum from farmers was significantly higher compared to urban dwellers. The same was true for both granzymes A and B. The results of this study suggest that LL-37 and granzymes A and B may add to the development of COPD. The results suggest also their role in an organism's response to organic dust exposure.
Although much is known about the initiation of immune responses, much less is known about what controls the effector phase. CD8(+) T cell responses are believed to be programmed in lymph nodes during priming without any further contribution by dendritic cells (DCs) and Ag. In this study, we report t
he requirement for DCs, Ag, and CD28 costimulation during the effector phase of the CD8(+) T cell response. Depleting DCs or blocking CD28 after day 6 of primary influenza A virus infection decreases the virus-specific CD8(+) T cell response by inducing apoptosis, and this results in decreased viral clearance. Furthermore, effector CD8(+) T cells adoptively transferred during the effector phase fail to expand without DC, CD28 costimulation, and cognate Ag. The absence of costimulation also leads to reduced survival of virus-specific effector cells as they undergo apoptosis mediated by the proapoptotic molecule Bim. Finally, IL-2 treatment restored the effector response in the absence of CD28 costimulation. Thus, in contrast to naive CD8(+) T cells, which undergo an initial Ag-independent proliferation, effector CD8(+) T cells expanding in the lungs during the effector phase require Ag, CD28 costimulation, and DCs for survival and expansion. These requirements would greatly impair effector responses against viruses and tumors that are known to inhibit DC maturation and in chronic infections and aging where CD28(-/-) CD8(+) T cells accumulate.
In brain tumors the main source of energy is from glycolysis, which is initiated by hexokinase 1 (HK1), an enzyme bound to the mitochondrial porin. Disruption of HK binding greatly affects tumor cell survival. Little is known about the acceptor site of HK1. Therefore, a polyclonal antibody (Pab) dir
ected to MIAAQLLAYYFTELK (MK) peptide, corresponding to the 15-amino acids of the N-terminal sequence of brain HK1 was obtained. Anti MK antibody (aMK-Pab)bound specifically to HK as shown by ELISA. The aMK-Pab binding to MK peptide was antibody-concentration dependent and was completely abolished by its preincubation with the peptide at 6 x 10-8 M. The aMK-Pab recognized cytosolic HK (cHK) and HK solubilized (sHK)from rat-brain mitochondrial preparations, but not the yeast HK which does not have the MK sequence. An anti-brain HK Pab (aHK-Pab) directed to purified HK recognized the MK peptide; aHK-Pab bound to MK and this binding was inhibited by preincubation of the antibody with the MK peptide. It was previously demonstrated that brain HK anchors to mitochondria porins, also designated as voltage dependent-anion channels (VDAC) via the MK sequence. A specific anti-VDAC antibody (aVDAC-Pab) which specifically bound the N and C-terminal sequences of VDACwas found to bind to c-HK, sHK and MK-coated wells and this binding was abolished by aVDACPabpreincubation with MK peptide. These data suggest that the three Pabs cross-react with an epitope present in HK and VDAC, and which was presented in the MK peptide. Comparison of alignment of HK or VDAC sequences, available in the protein data bank (PDB), did not allow putative homologues responsible for the cross-reaction to be identified, suggesting that the epitope is conformational. This, added to inhibition of mitochondria-isolated HK binding by the MK peptide,suggests that there is an homophilic-type interaction between HK and porin, through a peptidic structure represented at least in part in the MK peptide.
Zhang Q, etal., Blood. 2016 Mar 31;127(13):1687-700. doi: 10.1182/blood-2015-08-665604. Epub 2016 Jan 21.
Targeting oncogenic transcription factor signal transducer and activator of transcription 3 (STAT3) in acute myeloid leukemia (AML) can reduce blast survival and tumor immune evasion. Decoy oligodeoxynucleotides (dODNs), which comprise STAT3-specific DNA sequences are competitive inhibition of STAT3
transcriptional activity. To deliver STAT3dODN specifically to myeloid cells, we linked STAT3dODN to the Toll-like receptor 9 (TLR9) ligand, cytosine guanine dinucleotide (CpG). The CpG-STAT3dODN conjugates are quickly internalized by human and mouse TLR9(+)immune cells (dendritic cells, B cells) and the majority of patients' derived AML blasts, including leukemia stem/progenitor cells. Following uptake, CpG-STAT3dODNs are released from endosomes, and bind and sequester cytoplasmic STAT3, thereby inhibiting downstream gene expression in target cells. STAT3 inhibition in patients' AML cells limits their immunosuppressive potential by reduced arginase expression, thereby partly restoring T-cell proliferation. Partly chemically modified CpG-STAT3dODNs have >60 hours serum half-life which allows for IV administration to leukemia-bearing mice (50% effective dose approximately 2.5 mg/kg). Repeated administration of CpG-STAT3dODN resulted in regression of human MV4-11 AML in mice. The antitumor efficacy of this strategy is further enhanced in immunocompetent mice by combining direct leukemia-specific cytotoxicity with immunogenic effects of STAT3 blocking/TLR9 triggering. CpG-STAT3dODN effectively reducedCbfb/MYH11/MplAML burden in various organs and eliminated leukemia stem/progenitor cells, mainly through CD8/CD4 T-cell-mediated immune responses. In contrast, small-molecule Janus kinase 2/STAT3 inhibitor failed to reproduce therapeutic effects of cell-selective CpG-STAT3dODN strategy. These results demonstrate therapeutic potential of CpG-STAT3dODN inhibitors with broad implications for treatement of AML and potentially other hematologic malignancies.
Mitochondria have been derived from alpha-bacterial endosymbionts during the evolution of eukaryotes. Numerous bacterial functions have been maintained inside the organelles including fatty acid degradation, citric acid cycle, oxidative phosphorylation, and the synthesis of heme or lipoic acid cofac
tors. Additionally, mitochondria have inherited the bacterial iron-sulfur cluster assembly (ISC) machinery. Many of the ISC components are essential for cell viability because they generate a still unknown, sulfur-containing compound for the assembly of cytosolic and nuclear Fe/S proteins that perform important functions in, e.g., protein translation, DNA synthesis and repair, and chromosome segregation. The sulfur-containing compound is exported by the mitochondrial ABC transporter Atm1 (human ABCB7) and utilized by components of the cytosolic iron-sulfur protein assembly (CIA) machinery. An appealing minimal model for the striking compartmentation of eukaryotic Fe/S protein biogenesis is provided by organisms that contain mitosomes instead of mitochondria. Mitosomes have been derived from mitochondria by reductive evolution, during which they have lost virtually all classical mitochondrial tasks. Nevertheless, mitosomes harbor all core ISC components which presumably have been maintained for assisting the maturation of cytosolic-nuclear Fe/S proteins. The current review is centered around the Atm1 export process. We present an overview on the mitochondrial requirements for the export reaction, summarize recent insights into the 3D structure and potential mechanism of Atm1, and explain how the CIA machinery uses the mitochondrial export product for the assembly of cytosolic and nuclear Fe/S proteins.
Hossain DM, etal., Clin Cancer Res. 2015 Aug 15;21(16):3771-82. doi: 10.1158/1078-0432.CCR-14-3145. Epub 2015 May 12.
PURPOSE: Recent advances in immunotherapy of advanced human cancers underscored the need to address and eliminate tumor immune evasion. The myeloid-derived suppressor cells (MDSC) are important inhibitors of T-cell responses in solid tumors, such as prostate cancers. However, targeting MDSCs proved
challenging due to their phenotypic heterogeneity. EXPERIMENTAL DESIGN: Myeloid cell populations were evaluated using flow cytometry on blood samples, functional assays, and immunohistochemical/immunofluorescent stainings on specimens from healthy subjects, localized and metastatic castration-resistant prostate cancer patients. RESULTS: Here, we identify a population of Lin(-)CD15(HI)CD33(LO) granulocytic MDSCs that accumulate in patients' circulation during prostate cancer progression from localized to metastatic disease. The prostate cancer-associated MDSCs potently inhibit autologous CD8(+) T cells' proliferation and production of IFNgamma and granzyme-B. The circulating MDSCs have high levels of activated STAT3, which is a central immune checkpoint regulator. The granulocytic pSTAT3(+) cells are also detectable in patients' prostate tissues. We previously generated an original strategy to silence genes specifically in Toll-like Receptor-9 (TLR9) positive myeloid cells using CpG-siRNA conjugates. We demonstrate that human granulocytic MDSCs express TLR9 and rapidly internalize naked CpG-STAT3siRNA, thereby silencing STAT3 expression. STAT3 blocking abrogates immunosuppressive effects of patients-derived MDSCs on effector CD8(+) T cells. These effects depended on reduced expression and enzymatic activity of Arginase-1, a downstream STAT3 target gene and a potent T-cell inhibitor. CONCLUSIONS: Overall, we demonstrate the accumulation of granulocytic MDSCs with prostate cancer progression and the feasibility of using TLR9-targeted STAT3siRNA delivery strategy to alleviate MDSC-mediated immunosuppression.
da Cunha AA, etal., Mol Cell Biochem. 2011 Dec;358(1-2):153-60. doi: 10.1007/s11010-011-0930-2. Epub 2011 Jun 30.
Tissue accumulation of homocysteine occurs in classical homocystinuria, a metabolic disease characterized biochemically by cystathionine beta-synthase deficiency. Vascular manifestations such as myocardial infarction, cerebral thrombosis, hepatic steatosis, and pulmonary embolism are common in this
disease and poorly understood. In this study, we investigated the effect of chronic hyperhomocysteinemia on some parameters of oxidative stress (thiobarbituric acid-reactive substances, protein carbonyl content, 2',7'-dichlorofluorescein fluorescence assay, and total radical-trapping antioxidant potent) and activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) in the rat lung. Reduced glutathione content and glucose 6-phosphate dehydrogenase activity, as well as nitrite levels, were also evaluated. Wistar rats received daily subcutaneous injections of Hcy (0.3-0.6 mumol/g body weight) from the 6th to the 28th days-of-age and the control group received saline. One and 12 h after the last injection, rats were killed and the lungs collected. Hyperhomocysteinemia increased lipid peroxidation and oxidative damage to protein, and disrupted antioxidant defenses (enzymatic and non-enzymatic) in the lung of rats, characterizing a reliable oxidative stress. In contrast, this amino acid did not alter nitrite levels. Our findings showed a consistent profile of oxidative stress in the lung of rats, elicited by homocysteine, which could explain, at least in part, the mechanisms involved in the lung damage that is present in some homocystinuric patients.
Phenylketonuria (PKU) is a disorder caused by a deficiency in phenylalanine hydroxylase activity, which converts phenylalanine (Phe) to tyrosine, leading to hyperphenylalaninemia (HPA) with accumulation of Phe in tissues of patients. The neuropathophysiology mechanism of disease remains unknown. H
owever, recently the involvement of oxidative stress with decreased glutathione levels in PKU has been reported. Intracellular glutathione (GSH) levels may be maintained by the antioxidant action of lipoic acid (LA). The aim of this study was to evaluate the activity of the enzymes involved in the metabolism and function of GSH, such as glutathione peroxidase (GSH-Px), glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GR), glutamate-cysteine ligase (GCL), glutathione-S-transferase (GST) and GSH content in brain and liver of young rats subjected to a chemically induced model of HPA and the effect of LA for a week. In brain, the administration of Phe reduced the activity of the GSH-Px, GR and G6PD and LA prevented these effects totally or partially. GCL activity was increased by HPA and was not affect by LA antioxidant treatment. GST activity did not differ between groups. GSH content was increased by LA and decreased by HPA treatment in brain samples. Considering the liver, all parameters analyzed were increased in studied HPA animals and LA was able to hinder some effects except for the GCL, GST enzymes and GSH content. These results suggested that HPA model alter the metabolism of GSH in rat brain and liver, which may have an important role in the maintenance of GSH function in PKU although liver is not a directly affected organ in this disease. So, an antioxidant therapy with LA may be useful in the treatment of oxidative stress in HPA.
Phenylketonuria (PKU) is an inherited metabolic disorder caused by deficiency of phenylalanine hydroxylase which leads to accumulation of phenylalanine and its metabolites in tissues of patients with severe neurological involvement. Recently, many studies in animal models or patients have reported
the role of oxidative stress in PKU. In the present work we studied the effect of lipoic acid against oxidative stress in rat brain provoked by an animal model of hyperphenylalaninemia (HPA), induced by repetitive injections of phenylalanine and alpha-methylphenylalanine (a phenylalanine hydroxylase inhibitor) for 7 days, on some oxidative stress parameters. Lipoic acid prevented alterations on catalase (CAT) and superoxide dismutase (SOD), and the oxidative damage of lipids, proteins, and DNA observed in HPA rats. In addition, lipoic acid diminished reactive species generation compared to HPA group which was positively correlated to SOD/CAT ratio. We also observed that in vitro Phe inhibited CAT activity while phenyllactic and phenylacetic acids stimulated superoxide dismutase activity. These results demonstrate the efficacy of lipoic acid to prevent oxidative stress induced by HPA model in rats. The possible benefits of lipoic acid administration to PKU patients should be considered.
Almeida Pereira Leite ST, etal., Ann Hepatol. 2013 Sep-Oct;12(5):733-9.
INTRODUCTION: The progression of hepatic disease in chronic viral hepatitis is accompanied by an increased production of reactive oxygen species (ROS), as well as an accumulation of oxidative DNA damage, which is primarily repaired through base excision repair. XRCC1 (X-ray repair cross c
omplementing protein 1) is one of the most important proteins involved in this repair pathway. The present study was carried out to verify the possible association of the XRCC1 rs25487 polymorphism with cirrhosis in patients from Central-West Brazil. MATERIAL AND METHODS: A total of 227 individuals with viral hepatitis, 53 cirrhotic and 174 non-cirrhotic, were genotyped for the XRCC1 rs25487 polymorphism using PCR-RFLP. RESULTS: There were significantly higher frequencies of both the Arg/Gln genotype and of individuals with at least one Gln allele (Arg/ Gln+Gln/Gln) among cirrhotic patients (56.6% and 69.8%) compared with non-cirrhotic patients (25.8% and 37.9%). Both conditions were significantly associated with cirrhosis, independent of age, sex, alcohol intake or tobacco use (adjusted OR = 3.5, CI = 1.7-7.4, p = 0.001 and adjusted OR = 3.1, CI = 1.5-6.3, p = 0.002, respectively). Similar results were obtained for a group of HCV-infected patients but not for HBV-infected patients. CONCLUSIONS: The XRCC1 rs25487 polymorphism may influence the development of cirrhosis in viral hepatitis patients, and additional investigation will be necessary.
Leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) encodes an inner mitochondrial membrane protein with an osmoregulatory function controlling mitochondrial volume and ion homeostasis. The putative association of LETM1 with a human disease was initially suggested in Wolf-Hirschhorn sy
ndrome, a disorder that results from de novo monoallelic deletion of chromosome 4p16.3, a region encompassing LETM1. Utilizing exome sequencing and international gene-matching efforts, we have identified 18 affected individuals from 11 unrelated families harboring ultra-rare bi-allelic missense and loss-of-function LETM1 variants and clinical presentations highly suggestive of mitochondrial disease. These manifested as a spectrum of predominantly infantile-onset (14/18, 78%) and variably progressive neurological, metabolic, and dysmorphic symptoms, plus multiple organ dysfunction associated with neurodegeneration. The common features included respiratory chain complex deficiencies (100%), global developmental delay (94%), optic atrophy (83%), sensorineural hearing loss (78%), and cerebellar ataxia (78%) followed by epilepsy (67%), spasticity (53%), and myopathy (50%). Other features included bilateral cataracts (42%), cardiomyopathy (36%), and diabetes (27%). To better understand the pathogenic mechanism of the identified LETM1 variants, we performed biochemical and morphological studies on mitochondrial K+/H+ exchange activity, proteins, and shape in proband-derived fibroblasts and muscles and in Saccharomyces cerevisiae, which is an important model organism for mitochondrial osmotic regulation. Our results demonstrate that bi-allelic LETM1 variants are associated with defective mitochondrial K+ efflux, swollen mitochondrial matrix structures, and loss of important mitochondrial oxidative phosphorylation protein components, thus highlighting the implication of perturbed mitochondrial osmoregulation caused by LETM1 variants in neurological and mitochondrial pathologies.
Voss JO, etal., Biomed Res Int. 2015;2015:714230. doi: 10.1155/2015/714230. Epub 2015 Dec 22.
INTRODUCTION: Human mesenchymal stromal cells (hMSCs) exhibit the potential to accelerate bone healing by enhanced osteogenic differentiation. Interleukin-1beta is highly expressed during fracture healing and has been demonstrated to exert a significant impact on the differentiation behaviour of hM
SCs. Here, we investigate the effect of 2-hour IL-1beta stimulation on the differentiation and paracrine activity of hMSCs in coculture with osteosarcoma cells in vitro. METHODS: hMSCs from 3 donors were incubated for 2 hours with 10 ng/mL IL-1beta and subsequently cocultured with MG63-GFP cells either in control or in differentiation medium in a transwell system for 28 days. Genetic and functional effects were investigated. RESULTS: hMSCs cultured in control medium exhibited a regulatory effect on cocultured MG63-GFP cells, resulting in upregulation of osteogenic gene expression in combination with increased ALP activity. However, while stimulated hMSCs cultured under differentiation conditions exhibit signs of osteogenic differentiation, osteogenic differentiation also caused an impaired regulatory effect on the cocultured MG63-GFP cells. CONCLUSION: Short stimulation of hMSCs has the potential to modify their long-term behaviour. In addition, undifferentiated hMSCs are able to regulate osteoblast differentiation; however, this regulatory function is lost upon osteogenic differentiation in vitro. This offers a novel approach for clinical cell therapy protocols.
Hüffmeier U, etal., Orphanet J Rare Dis. 2021 Mar 18;16(1):136. doi: 10.1186/s13023-021-01744-1.
BACKGROUND: An identical homozygous missense variant in EIF3F, identified through a large-scale genome-wide sequencing approach, was reported as causative in nine individuals with a neurodevelopmental disorder, characterized by variable intellectual disability, epilepsy, behavioral proble
ms and sensorineural hearing-loss. To refine the phenotypic and molecular spectrum of EIF3F-related neurodevelopmental disorder, we examined independent patients. RESULTS: 21 patients were homozygous and one compound heterozygous for c.694T>G/p.(Phe232Val) in EIF3F. Haplotype analyses in 15 families suggested that c.694T>G/p.(Phe232Val) was a founder variant. All affected individuals had developmental delays including delayed speech development. About half of the affected individuals had behavioral problems, altered muscular tone, hearing loss, and short stature. Moreover, this study suggests that microcephaly, reduced sensitivity to pain, cleft lip/palate, gastrointestinal symptoms and ophthalmological symptoms are part of the phenotypic spectrum. Minor dysmorphic features were observed, although neither the individuals' facial nor general appearance were obviously distinctive. Symptoms in the compound heterozygous individual with an additional truncating variant were at the severe end of the spectrum in regard to motor milestones, speech delay, organic problems and pre- and postnatal growth of body and head, suggesting some genotype-phenotype correlation. CONCLUSIONS: Our study refines the phenotypic and expands the molecular spectrum of EIF3F-related syndromic neurodevelopmental disorder.
As the list of putative driver mutations in glioma grows, we are just beginning to elucidate the effects of dysregulated developmental signaling pathways on the transformation of neural cells. We have employed a postnatal, mosaic, autochthonous glioma model that captures the first hours and days of
gliomagenesis in more resolution than conventional genetically engineered mouse models of cancer. We provide evidence that disruption of the Nf1-Ras pathway in the ventricular zone at multiple signaling nodes uniformly results in rapid neural stem cell depletion, progenitor hyperproliferation, and gliogenic lineage restriction. Abolishing Ets subfamily activity, which is upregulated downstream of Ras, rescues these phenotypes and blocks glioma initiation. Thus, the Nf1-Ras-Ets axis might be one of the select molecular pathways that are perturbed for initiation and maintenance in glioma.
The phosphatidylinositol glycan anchor biosynthesis class S protein (PIGS) gene has recently been implicated in a novel congenital disorder of glycosylation resulting in autosomal recessive inherited glycosylphosphatidylinositol-anchored protein (GPI-AP) deficiency. Previous studies described seven
patients with biallelic variants in the PIGS gene, of whom two presented with fetal akinesia and five with global developmental delay and epileptic developmental encephalopathy. We present the molecular and clinical characteristics of six additional individuals from five families with unreported variants in PIGS. All individuals presented with hypotonia, severe global developmental delay, microcephaly, intractable early infantile epilepsy, and structural brain abnormalities. Additional findings include vision impairment, hearing loss, renal malformation, and hypotonic facial appearances with minor dysmorphic features but without a distinctive facial gestalt. Four individuals died due to neurologic complications. GPI anchoring studies performed on one individual revealed a significant decrease in GPI-APs. We confirm that biallelic variants in PIGS cause vitamin pyridoxine-responsive epilepsy due to inherited GPI deficiency and expand the genotype and phenotype of PIGS-related disorder. Further delineation of the molecular spectrum of PIGS-related disorders would improve management, help develop treatments, and encourage the expansion of diagnostic genetic testing to include this gene as a potential cause of neurodevelopmental disorders and epilepsy.
Parvaiz F, etal., World J Gastroenterol. 2015 Nov 21;21(43):12361-9. doi: 10.3748/wjg.v21.i43.12361.
AIM: To investigate the mechanisms of insulin resistance in human hepatoma cells expressing hepatitis C virus (HCV) nonstructural protein 5A (NS5A). METHODS: The human hepatoma cell lines, Huh7 and Huh7.5, were infected with HCV or transiently-transfected with a vector expressing HCV NS5A. The eff
ect of HCV NS5A on the status of the critical players involved in insulin signaling was analyzed using real-time quantitative polymerase chain reaction and Western blot assays. Data were analyzed using Graph Pad Prism version 5.0. RESULTS: To investigate the effect of insulin treatment on the players involved in insulin signaling pathway, we analyzed the status of insulin receptor substrate-1 (IRS-1) phosphorylation in HCV infected cells or Huh7.5 cells transfected with an HCV NS5A expression vector. Our results indicated that there was an increased phosphorylation of IRS-1 (Ser(307)) in HCV infected or NS5A transfected Huh7.5 cells compared to their respective controls. Furthermore, an increased phosphorylation of Akt (Ser(473)) was observed in HCV infected and NS5A transfected cells compared to their mock infected cells. In contrast, we observed decreased phosphorylation of Akt Thr308 phosphorylation in HCV NS5A transfected cells. These results suggest that Huh7.5 cells either infected with HCV or ectopically expressing HCV NS5A alone have the potential to induce insulin resistance by the phosphorylation of IRS-1 at serine residue (Ser(307)) followed by decreased phosphorylation of Akt Thr(308), Fox01 Ser(256) and GSK3beta Ser(9), the downstream players of the insulin signaling pathway. Furthermore, increased expression of PECK and glucose-6-phosphatase, the molecules involved in gluconeogenesis, in HCV NS5A transfected cells was observed. CONCLUSION: Taken together, our results suggest the role of HCV NS5A in the induction of insulin resistance by modulating various cellular targets involved in the insulin signaling pathway.
McRae S, etal., J Biol Chem. 2016 Feb 12;291(7):3254-67. doi: 10.1074/jbc.M115.694059. Epub 2015 Dec 23.
Hepatitis C virus (HCV) relies on host lipids and lipid droplets for replication and morphogenesis. The accumulation of lipid droplets in infected hepatocytes manifests as hepatosteatosis, a common pathology observed in chronic hepatitis C patients. One way by which HCV promotes the accumulation o
f intracellular lipids is through enhancing de novo lipogenesis by activating the sterol regulatory element-binding proteins (SREBPs). In general, activation of SREBPs occurs during cholesterol depletion. Interestingly, during HCV infection, the activation of SREBPs occurs under normal cholesterol levels, but the underlying mechanisms are still elusive. Our previous study has demonstrated the activation of the inflammasome complex in HCV-infected human hepatoma cells. In this study, we elucidate the potential link between chronic hepatitis C-associated inflammation and alteration of lipid homeostasis in infected cells. Our results reveal that the HCV-activated NLRP3 inflammasome is required for the up-regulation of lipogenic genes such as 3-hydroxy-3-methylglutaryl-coenzyme A synthase, fatty acid synthase, and stearoyl-CoA desaturase. Using pharmacological inhibitors and siRNA against the inflammasome components (NLRP3, apoptosis-associated speck-like protein containing a CARD, and caspase-1), we further show that the activation of the NLRP3 inflammasome plays a critical role in lipid droplet formation. NLRP3 inflammasome activation in HCV-infected cells enables caspase-1-mediated degradation of insulin-induced gene proteins. This subsequently leads to the transport of the SREBP cleavage-activating protein.SREBP complex from the endoplasmic reticulum to the Golgi, followed by proteolytic activation of SREBPs by S1P and S2P in the Golgi. Typically, inflammasome activation leads to viral clearance. Paradoxically, here we demonstrate how HCV exploits the NLRP3 inflammasome to activate SREBPs and host lipid metabolism, leading to liver disease pathogenesis associated with chronic HCV.
Fliedner A, etal., Am J Hum Genet. 2020 Sep 3;107(3):544-554. doi: 10.1016/j.ajhg.2020.06.019. Epub 2020 Jul 29.
RNA polymerase II interacts with various other complexes and factors to ensure correct initiation, elongation, and termination of mRNA transcription. One of these proteins is SR-related CTD-associated factor 4 (SCAF4), which is important for correct usage of polyA sites for mRNA termination. Using e
xome sequencing and international matchmaking, we identified nine likely pathogenic germline variants in SCAF4 including two splice-site and seven truncating variants, all residing in the N-terminal two thirds of the protein. Eight of these variants occurred de novo, and one was inherited. Affected individuals demonstrated a variable neurodevelopmental disorder characterized by mild intellectual disability, seizures, behavioral abnormalities, and various skeletal and structural anomalies. Paired-end RNA sequencing on blood lymphocytes of SCAF4-deficient individuals revealed a broad deregulation of more than 9,000 genes and significant differential splicing of more than 2,900 genes, indicating an important role of SCAF4 in mRNA processing. Knockdown of the SCAF4 ortholog CG4266 in the model organism Drosophila melanogaster resulted in impaired locomotor function, learning, and short-term memory. Furthermore, we observed an increased number of active zones in larval neuromuscular junctions, representing large glutamatergic synapses. These observations indicate a role of CG4266 in nervous system development and function and support the implication of SCAF4 in neurodevelopmental phenotypes. In summary, our data show that heterozygous, likely gene-disrupting variants in SCAF4 are causative for a variable neurodevelopmental disorder associated with impaired mRNA processing.
UNLABELLED: In advanced cirrhosis, impaired function is caused by intrinsic damage to the native liver cells and from the abnormal microenvironment in which the cells reside. The extent to which each plays a role in liver failure and regeneration is unknown. To examine this issue, hepatoc
ytes from cirrhotic and age-matched control rats were isolated, characterized, and transplanted into the livers of noncirrhotic hosts whose livers permit extensive repopulation with donor cells. Primary hepatocytes derived from livers with advanced cirrhosis and compensated function maintained metabolic activity and the ability to secrete liver-specific proteins, whereas hepatocytes derived from cirrhotic livers with decompensated function failed to maintain metabolic or secretory activity. Telomere studies and transcriptomic analysis of hepatocytes recovered from progressively worsening cirrhotic livers suggest that hepatocytes from irreversibly failing livers show signs of replicative senescence and express genes that simultaneously drive both proliferation and apoptosis, with a later effect on metabolism, all under the control of a central cluster of regulatory genes, including nuclear factor κB and hepatocyte nuclear factor 4α. Cells from cirrhotic and control livers engrafted equally well, but those from animals with cirrhosis and failing livers showed little initial evidence of proliferative capacity or function. Both, however, recovered more than 2 months after transplantation, indicating that either mature hepatocytes or a subpopulation of adult stem cells are capable of full recovery in severe cirrhosis. CONCLUSION: Transplantation studies indicate that the state of the host microenvironment is critical to the regenerative potential of hepatocytes, and that a change in the extracellular matrix can lead to regeneration and restoration of function by cells derived from livers with end-stage organ failure.
Yokoyama S, etal., Nature. 2011 Nov 13;480(7375):99-103. doi: 10.1038/nature10630.
So far, two genes associated with familial melanoma have been identified, accounting for a minority of genetic risk in families. Mutations in CDKN2A account for approximately 40% of familial cases, and predisposing mutations in CDK4 have been reported in a very small number of melanoma kindreds. Her
e we report the whole-genome sequencing of probands from several melanoma families, which we performed in order to identify other genes associated with familial melanoma. We identify one individual carrying a novel germline variant (coding DNA sequence c.G1075A; protein sequence p.E318K; rs149617956) in the melanoma-lineage-specific oncogene microphthalmia-associated transcription factor (MITF). Although the variant co-segregated with melanoma in some but not all cases in the family, linkage analysis of 31 families subsequently identified to carry the variant generated a log of odds (lod) score of 2.7 under a dominant model, indicating E318K as a possible intermediate risk variant. Consistent with this, the E318K variant was significantly associated with melanoma in a large Australian case-control sample. Likewise, it was similarly associated in an independent case-control sample from the United Kingdom. In the Australian sample, the variant allele was significantly over-represented in cases with a family history of melanoma, multiple primary melanomas, or both. The variant allele was also associated with increased naevus count and non-blue eye colour. Functional analysis of E318K showed that MITF encoded by the variant allele had impaired sumoylation and differentially regulated several MITF targets. These data indicate that MITF is a melanoma-predisposition gene and highlight the utility of whole-genome sequencing to identify novel rare variants associated with disease susceptibility.
Non-Hodgkin lymphoma of Waldeyer's ring constitutes a small percentage of cases of palatine tonsil malignancies and its precise etiology remains unknown. RCAS1 (receptor cancer-binding antigen expressed on SiSo cells) has been demonstrated to be associated with poor prognosis, the development of lym
ph node metastases and participation in tumor microenvironment remodeling. Our aim is to analyze the potential role of RCAS1 expression in the tumor and tumor microenvironment in the development of early-stage palatine tonsil B-cell lymphomas. We selected 20 patients and analyzed tissue samples from the lymphoma and tumor microenvironment of each patient and from a reference group of 20 patients with chronic tonsillitis. The presence of RCAS1 protein immunoreactivity was demonstrated in 65% of the examined tissue samples of diffuse large B-cell lymphoma and in 25% of the analyzed stromata in which it was exhibited by CD68-positive cells identified as macrophages and dispersed throughout the stroma. RCAS1 immunoreactivity in the lymphoma tissue samples remained at a level comparable with that of the reference and was significantly higher in these samples than in those from the stroma. Chronic inflammation of the palatine tonsils thus results in intensive infiltration by various types of immune system cells and in excessive RCAS1 immunoreactivity, both of which confirm the important regulatory role of RCAS1 in the immune response in the mucosa-associated lymphatic tissue of Waldeyer's ring. RCAS1 seems to be involved in creating tumor-induced inflammation in the tumor and its microenvironment.
Riedhammer KM, etal., Brain. 2021 Mar 3;144(2):411-419. doi: 10.1093/brain/awaa410.
Claudin-11, a tight junction protein, is indispensable in the formation of the radial component of myelin. Here, we report de novo stop-loss variants in the gene encoding claudin-11, CLDN11, in three unrelated individuals presenting with an early-onset spastic movement disorder, expressive speech di
sorder and eye abnormalities including hypermetropia. Brain MRI showed a myelin deficit with a discrepancy between T1-weighted and T2-weighted images and some progress in myelination especially involving the central and peripheral white matter. Exome sequencing identified heterozygous stop-loss variants c.622T>C, p.(*208Glnext*39) in two individuals and c.622T>G, p.(*208Gluext*39) in one individual, all occurring de novo. At the RNA level, the variant c.622T>C did not lead to a loss of expression in fibroblasts, indicating this transcript is not subject to nonsense-mediated decay and most likely translated into an extended protein. Extended claudin-11 is predicted to form an alpha helix not incorporated into the cytoplasmic membrane, possibly perturbing its interaction with intracellular proteins. Our observations suggest that stop-loss variants in CLDN11 expand the genetically heterogeneous spectrum of hypomyelinating leukodystrophies.
OBJECTIVE: Endometrium is a specialized organ in which phenomena controlling the level of cell proliferation and apoptosis are marked. The aim of our study was to determine the presence of proteins involved in apoptosis and proliferation: RCAS1, MT and the number of CD56-positive cells and their act
ivity to elucidate their possible role in the development of adenocarcinoma and endometriosis. MATERIALS AND METHODS: MT, RCAS1, CD56-positivity and CD69 expression were assessed in 55 tissue samples by Western blot and immunohistochemistry methods. RESULTS: We found that endometrium during secretory menstrual cycle phase is characterized by significantly higher RCAS1 and higher MT expression than in proliferative phase. The number of CD56-positive cells and the CD69 antigen expression was significantly increased. Endometrial adenocarcinoma was characterized by significantly increased RCAS1 expression, while MT expression was comparable to the level found in the secretory phase. The number of CD56-positive cells was significantly decreased and their activity was comparable to the level found in the secretory phase. Endometriosis was accompanied by significantly lower RCAS1 and MT expressions, with lower number of CD-56 positive cells and lower expression of CD69 antigen in comparison to the secretory phase. CONCLUSIONS: The ability of endometrium to determine cytotoxic activity (RCAS1 expression changes) and high protection against DNA damage (MT expression) with concomitant changes in the number of immune cells and their activity, observed in normal endometrium during the menstrual cycle phases seems to be fundamental for pathological features of endometrial adenocarcinoma and endometriosis.
Post-transplant lymphoproliferative disorders (PTLDs) are potentially fatal, often Epstein-Barr virus (EBV)-driven neoplasias developing in immunocompromised hosts. Initial treatment usually consists of a reduction in immunosuppressive therapy and/or rituximab with or without chemotherapy. However,
patients who relapse do poorly, and new treatment options are warranted. With the introduction of the immunoconjugate brentuximab vedotin, the CD30 antigen has become an effectively targetable molecule. Therefore, we investigated the frequency and level of CD30 expression in PTLDs. We identified 108 patients with PTLDs diagnosed during 1994-2011, of whom 62 had adequate paraffin-embedded tissue for tissue microarray construction. Immunohistochemical expression of CD30 was consistently detected in all types of PTLD (overall 85.25%), including the monomorphic subtypes, and was correlated with a more favorable outcome. For diffuse large B-cell lymphoma (DLBCL)-type PTLD this was regardless of EBV status, and remained significant in multivariate analysis. Cell-of-origin had no independent prognostic value in our series of DLBCL PTLD.
Analysis of 501 melanoma exomes identified RASA2, encoding a RasGAP, as a tumor-suppressor gene mutated in 5% of melanomas. Recurrent loss-of-function mutations in RASA2 were found to increase RAS activation, melanoma cell growth and migration. RASA2 expression was lost in >/=30% of human melanomas
and was associated with reduced patient survival. These findings identify RASA2 inactivation as a melanoma driver and highlight the importance of RasGAPs in cancer.
The epigenetic modifier EZH2 is part of the polycomb repressive complex that suppresses gene expression via histone methylation. Activating mutations in EZH2 are found in a subset of melanoma that contributes to disease progression by inactivating tumor suppressor genes. In this study we have targe
ted EZH2 with a specific inhibitor (GSK126) or depleted EZH2 protein by stable shRNA knockdown. We show that inhibition of EZH2 has potent effects on the growth of both wild-type and EZH2 mutant human melanoma in vitro particularly in cell lines harboring the EZH2Y646 activating mutation. This was associated with cell cycle arrest, reduced proliferative capacity in both 2D and 3D culture systems, and induction of apoptosis. The latter was caspase independent and mediated by the release of apoptosis inducing factor (AIFM1) from mitochondria. Gene expression arrays showed that several well characterized tumor suppressor genes were reactivated by EZH2 inhibition. This included activating transcription factor 3 (ATF3) that was validated as an EZH2 target gene by ChIP-qPCR. These results emphasize a critical role for EZH2 in the proliferation and viability of melanoma and highlight the potential for targeted therapy against EZH2 in treatment of patients with melanoma.
Popiela TJ, etal., Neuro Endocrinol Lett. 2006 Dec;27(6):786-94.
INTRODUCTION: The generation of proper immune response in the tumor environment seems to be essential in antitumor defense. RCAS1 expression has been shown to participate in the regulation of immune cytotoxic activity, metallothionein participates in the protection of cells against immune mediated a
poptosis. Since MT and RCAS1 expression is observed within healthy tumor environment we aimed to focus on the proteins expression in tumor and its healthy adjacent tissue in invasive ductal breast cancer regarding the immune cells presence and activity. MATERIAL AND METHODS: RCAS1, metallothionein, CD3, CD56, CD4, CD25, CD69, CD68 and CD16 antigens expression was assessed by immunohistochemistry in invasive ductal breast cancer. Tissue samples were obtained from 45 patients and were grouped according to the presence of lymph nodes metastases. Two groups were obtained: with and without lymph nodes metastases. RESULTS: Significant differences were observed in RCAS1 and metallothionein expression in tumor and significant differences in metallothionein expression in healthy stroma regarding the presence of lymph nodes metastases. The significantly higher RCAS1 expression was noticed in tumor in comparison to stroma in patients with the presence of lymph nodes metastases. No such difference was observed in patients without the metastases. Significantly higher metallothionein expression was identified in tumor than in stroma in both groups of patients, with and without lymph nodes metastases. These changes in RCAS1 and metallothionein expression were significantly related with the changes in the number and activity of immune cells. CONCLUSION: RCAS1 and metallothionein expression in breast cancer healthy stroma seems to be essential for the coexistence of cytotoxic immune cells and normal epithelial cells. The loss of the ability to compensate the growing cytotoxic immune response in the environment might participate in the development of tumor spread.
BACKGROUND: Classical Hodgkin's lymphoma is characterized by a minority of neoplastic cells surrounded by a heterogeneous background population of non-neoplastic cells including lymphoma-associated macrophages. High levels of expression of both the monocyte/macrophage lineage-associated a
ntigens CD68 and CD163 have been suggested to have pro-tumor effects. The aim of our study was to correlate expression of CD68 and CD163 with the clinico-pathological features and prognosis of a cohort of patients with previously untreated Hodgkin's lymphoma. DESIGN AND METHODS: A tissue microarray was constructed from paraffin-embedded tumor tissues from 288 cases of classical Hodgkin's lymphoma. CD68 and CD163 expression was assessed immunohistochemically and the degree of macrophage infiltration within the tumor was scored using point grid counting. Clinical data were obtained from clinical records. RESULTS: The patients' median age was 37 years (range, 6-86 years). The male to female ratio was 1.2. In classical Hodgkin's lymphoma (n = 288) high CD68 and CD163 expression correlated, at the univariate level, with poorer overall survival (P=0.002 and P=0.03, respectively) and event-free survival (P=0.03 and P=0.04, respectively). At the multivariate level, high CD68 expression remained significantly predictive of overall survival (P=0.004). In addition, we demonstrated that both high CD68 and CD163 expression were associated with the presence of Epstein-Barr virus in the neoplastic cells (P=0.001 and P=0.0002, respectively). CONCLUSIONS: In classical Hodgkin's lymphoma, high expression of the macrophage/monocyte-related antigens CD68 and CD163 correlates with adverse outcome and with the presence of Epstein-Barr virus in the tumor cell population.
Breton C, etal., Am J Physiol Endocrinol Metab. 2009 Mar;296(3):E462-72. Epub 2008 Dec 16.
Epidemiological studies suggest that maternal undernutrition predisposes the offspring to development of energy balance metabolic pathologies in adulthood. Using a model of a prenatal maternal 70% food-restricted diet (FR30) in rats, we evaluated peripheral parameters involved in nutritional regulat
ion, as well as the hypothalamic appetite-regulatory system, in nonfasted and 48-h-fasted adult offspring. Despite comparable glycemia in both groups, mild glucose intolerance, with a defect in glucose-induced insulin secretion, was observed in FR30 animals. They also exhibited hyperleptinemia, despite similar visible fat deposits. Using semiquantitative RT-PCR, we observed no basal difference of hypothalamic proopiomelanocortin (POMC) and neuropeptide Y (NPY) gene expression, but a decrease of the OB-Rb and an increase of insulin receptor mRNA levels, in FR30 animals. These animals also exhibited basal hypercorticosteronemia and a blunted increase of corticosterone in fasted compared with control animals. After fasting, FR30 animals showed no marked reduction of POMC mRNA levels or intensity of beta-endorphin-immunoreactive fiber projections. By contrast, NPY gene expression and immunoreactive fiber intensity increased. FR30 rats also displayed subtle alterations of food intake: body weight-related food intake was higher and light-dark phase rhythm and refeeding time course were modified after fasting. At rest, in the morning, hyperinsulinemia and a striking increase in the number of c-Fos-containing cells in the arcuate nucleus were observed. About 30% of the c-Fos-expressing cells were POMC neurons. Our data suggest that maternal undernutrition differently programs the long-term appetite-regulatory system of offspring, especially the response of POMC neurons to energy status and food intake rhythm.
Laborie C, etal., Neurosci Lett. 2005 Jun 24;381(3):211-6.
We have previously shown that prenatal morphine exposure inhibited the hypothalamo-pituitary-adrenal (HPA) axis and altered the hypothalamic metabolism of serotonin during the early postnatal period in the rat and induced a chronic sympathoadrenal hyperactivity under resting conditions in adult male
rats. In this study, we examined the effects of prenatal morphine exposure on the responsiveness to an acute ether inhalation stress of the sympathoadrenal and HPA axis and the hippocampal and hypothalamic concentrations of serotonin (5HT) and 5-hydroxylindoleacetic acid (5HIAA) in 3-month-old male rats. The plasma levels of adrenocorticopic hormone (ACTH) and corticosterone (B) did not differ between the two groups both under resting conditions and after ether exposure. Ether inhalation increased adrenal tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) mRNA expression as well as adrenal epinephrine (E) concentration in control rats but not in prenatally morphine-exposed (PM) animals. Under basal conditions, hypothalamic concentrations of 5HT and 5HIAA increased in PM animals. In contrast to control animals, PM rats showed, in response to stress, an increased level of 5HT and 5HIAA in both the hypothalamus and in the hippocampus. In conclusion, prenatal morphine exposure produces long-lasting alterations in brain serotonin transmission and in the sympathoadrenal responsiveness to an acute systemic stress.
Petit F, etal., Eur J Hum Genet. 2016 Jan;24(1):37-43. doi: 10.1038/ejhg.2015.53. Epub 2015 Mar 18.
The expression gradient of the morphogen Sonic Hedgehog (SHH) is crucial in establishing the number and the identity of the digits during anteroposterior patterning of the limb. Its anterior ectopic expression is responsible for preaxial polydactyly (PPD). Most of these malformations are due to the
gain-of-function of the Zone of Polarizing Activity Regulatory Sequence, the only limb-specific enhancer of SHH known to date. We report a family affected with a novel condition associating PPD and hypertrichosis of the upper back, following an autosomal dominant mode of inheritance. This phenotype is consistent with deregulation of SHH expression during limb and follicle development. In affected members, we identified a 2 kb deletion located ~240 kb upstream from the SHH promoter. The deleted sequence is capable of repressing the transcriptional activity of the SHH promoter in vitro, consistent with a silencer activity. We hypothesize that the deletion of this silencer could be responsible for SHH deregulation during development, leading to a PPD-hypertrichosis phenotype.
Dos Santos RS, etal., Diabetes. 2017 Apr;66(4):1086-1096. doi: 10.2337/db16-0839. Epub 2017 Jan 10.
We describe a new syndrome characterized by early-onset diabetes associated with bone marrow failure, affecting mostly the erythrocytic lineage. Using whole-exome sequencing in a remotely consanguineous patient from a family with two affected siblings, we identified a single homozygous missense muta
tion (chr15.hg19:g.48,626,619A>G) located in the dUTPase (DUT) gene (National Center for Biotechnology Information Gene ID 1854), affecting both the mitochondrial (DUT-M p.Y142C) and the nuclear (DUT-N p.Y54C) isoforms. We found the same homozygous mutation in an unrelated consanguineous patient with diabetes and bone marrow aplasia from a family with two affected siblings, whereas none of the >60,000 subjects from the Exome Aggregation Consortium (ExAC) was homozygous for this mutation. This replicated observation probability was highly significant, thus confirming the role of this DUT mutation in this syndrome. DUT is a key enzyme for maintaining DNA integrity by preventing misincorporation of uracil into DNA, which results in DNA toxicity and cell death. We showed that DUT silencing in human and rat pancreatic β-cells results in apoptosis via the intrinsic cell death pathway. Our findings support the importance of tight control of DNA metabolism for β-cell integrity and warrant close metabolic monitoring of patients treated by drugs affecting dUTP balance.
Many genetic disorders demonstrate mutations that can be traced to a founder, sometimes a person who can be identified. These founder mutations have generated considerable interest, because they facilitate studies of prevalence and penetrance and can be used to quantify the degree of homogeneity wi
thin a population. This paper reports on founder mutations among the Dutch and relates their occurrence to the history and demography of the Netherlands. International migration, regional and religious endogamy, and rapid population growth played key roles in shaping the Dutch population. In the first millenniums BC and AD, the Netherlands were invaded by Celts, Romans, Huns, and Germans. In more recent times, large numbers of Huguenots and Germans migrated into the Netherlands. Population growth within the Netherlands was slow until the 19th century, when a period of rapid population growth started. Today, the Dutch population numbers 16 million inhabitants. Several different classes of founder mutations have been identified among the Dutch. Some mutations occur among people who represent genetic isolates within this country. These include mutations for benign familial cholestasis, diabetes mellitus, type I, infantile neuronal ceroid lipofuscinosis, L-DOPA responsive dystonia, and triphalangeal thumb. Although not related to a specific isolate, other founder mutations were identified only within the Netherlands, including those predisposing for hereditary breast-ovarian cancer, familial hypercholesterolemia, frontotemporal dementia, hereditary paragangliomas, juvenile neuronal ceroid lipofuscinosis, malignant melanoma, protein C deficiency, and San Filippo disease. Many of these show a regional distribution, suggesting dissemination from a founder. Some mutations that occur among the Dutch are shared with other European populations and others have been transmitted by Dutch emigres to their descendents in North America and South Africa. The occurrence of short chromosomal regions that have remained identical by descent has resulted in relatively limited genetic heterogeneity for many genetic conditions among the Dutch. These observations demonstrate the opportunity for gene discovery for other diseases and traits in the Netherlands.
Weegerink NJ, etal., Ann Otol Rhinol Laryngol. 2011 Mar;120(3):191-7.
OBJECTIVES: We describe the phenotype of 2 Dutch DFNA3 families with mutations in the GJB2 gene. METHODS: Two patients from family 1 and one isolated patient from family 2 were studied. The audiometric examination consisted of pure tone and speech audiometry. T
wo patients underwent vestibular testing and high-resolution computed tomographic scanning of the temporal bone. Mutation analysis of GJB2 and GJB6 was performed. RESULTS: All 3 patients had severe to profound sensorineural hearing impairment. Cochlear implantation was performed in 2 patients, and their phoneme recognition scores were good. Mutation analyses revealed a p.Arg184Gln mutation in GJB2 in family 1 and a p.Arg75Trp mutation in GJB2 in family 2. No mutations in GJB6 were identified. Vestibular function tests and computed tomographic scans yielded normal findings in the examined subjects. CONCLUSIONS: Severe to profound sensorineural hearing impairment was found in these DFNA3 patients, and was well rehabilitated with cochlear implantation. A thorough genotype-phenotype correlation is difficult because of the small number of affected patients and the limited clinical data of these patients. More clinical data on DFNA3 families need to be published in order to create a reliable and precise phenotype characterization.
Romeike BF, etal., Pathol Res Pract. 2005;201(11):727-32. Epub 2005 Oct 19.
The nuclear isoform of deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase, OMIM *601266, EC 3.6.1.23) is immunohistochemically detectable in all proliferating tissues and may thus be a useful adjunct for the grading of tumors analogous to Ki-67 labeling. A hundred and twenty-seven human intra
cranial tumors, including 56 astrocytomas, 12 oligodendrogliomas, 8 oligoastrocytomas, 34 meningiomas, 7 ependymomas, and 10 metastatic carcinomas, were stained using the monoclonal rat anti-human dUTPase antibody (clone 3E6) with formalin-fixed and paraffin-embedded tissue. The labeling indices were compared with those obtained with the proliferation marker Ki-67 on parallel tissue sections. All tumors contained dUTPase-positive nuclei, whereas the percentage of positive tumor cells generally increased with grade of malignancy. Meningiomas of higher grades, i.e., World Health Organization (WHO) grades II and III, contained additional cells with cytoplasmic reactivity. There were usually fewer dUTPase- than Ki-67-positive nuclei detectable. Unlike Ki-67, dUTPase was not detectable in mitotic figures. Labeling indices for dUTPase, but not for Ki-67, showed significant differences between all 3 WHO grades of diffuse astrocytomas. In summary, dUTPase staining provides a useful measure of cell proliferation distinct from that offered by Ki-67 labeling. It proved particularly useful for the evaluation of diffuse astrocytomas.
Congenital long QT syndrome (cLQTS) is electrocardiographically characterized by a prolonged QT interval and polymorphic ventricular arrhythmias (torsade de pointes). These cardiac arrhythmias may result in recurrent syncopes, seizure, or sudden death. LQTS can occur either as an autosomal dominant
(Romano Ward) or as an autosomal recessive disorder (Jervell and Lange-Nielsen syndrome). Mutations in at least five genes have been associated with the LQTS. Four genes, encoding cardiac ion channels, have been identified. The most common forms of LQTS are due to mutations in the potassium-channel genes KCNQ1 and HERG. We have screened 24 Dutch LQTS families for mutations in KCNQ1 and HERG. Fourteen missense mutations were identified. Eight of these missense mutations were novel: three in KCNQ1 and five in HERG. Novel missense mutations in KCNQ1 were Y184S, S373P, and W392R and novel missense mutations in HERG were A558P, R582C, G604S, T613M, and F640L. The KCNQ1 mutation G189R and the HERG mutation R582C were detected in two families. The pathogenicity of the mutations was based on segregation in families, absence in control individuals, the nature of the amino acid substitution, and localization in the protein. Genotype-phenotype studies indicated that auditory stimuli as trigger of cardiac events differentiate LQTS2 and LQTS1. In LQTS1, exercise was the predominant trigger. In addition, a number of asymptomatic gene defect carriers were identified. Asymptomatic carriers are still at risk of the development of life-threatening arrhythmias, underlining the importance of DNA analyses for unequivocal diagnosis of patients with LQTS.
van der Kooi AJ, etal., Neuromuscul Disord. 2013 Jun;23(6):456-60. doi: 10.1016/j.nmd.2013.03.012. Epub 2013 Apr 19.
A Dutch cohort of 105 limb girdle muscular dystrophy (LGMD) patients were subject to subsequent genetic investigations. In half the families a causative mutation was found. Recently mutations were identified in ANO5 causing LGMD2L and Miyoshi-like myopathy (MMD3
), but could also be found in patients with hyperCKemia only. Therefore, we analysed the index cases of the remaining 31 as yet undiagnosed families from our previously described cohort of LGMD patients for the presence of ANO5 mutations. Detailed history and neurological examination were available for all patients. Serum creatine kinase (CK) activity, skeletal muscle computed tomography (CT) and cardiological investigations were performed. Mutations in ANO5 were found in 16% of the families: 11 index patients and two sibs, eight males and five females. The founder mutation c.191dupA was present in 8 out of 13 patients. Ten different pathogenic mutations were identified of which seven were novel: five missense and two splice site mutations. The age of these patients ranged from 26 to 69 years and the age of onset varied from 21 to 57 years. Symptoms at onset were related to proximal leg weakness. The weakness was slowly progressive. Calf hypertrophy was present in three patients. Males were more severely affected than females. Serum CK activity was highly elevated in the early stage of disease and moderately increased in later stages. Muscle biopsy showed predominantly dystrophic changes. One patient had hypertrophic cardiomyopathy, two others had intraventricular septum thickening.
van Steensel MA, etal., Exp Dermatol. 2006 Sep;15(9):731-4.
Costello syndrome (CS) is a rare multiple congenital anomaly/mental retardation syndrome characterized by coarse face, loose skin and cardiomyopathy. It is often associated with benign and malignant tumors. Several groups have now demonstrated that CS is caused by recurring mutations in the HRAS gen
e in different ethnic groups. Here, we describe three unrelated Dutch patients and show that they all have the same mutation, G12S, in HRAS. To our knowledge, our patients are the first Dutch to be analysed. The syndrome seems to be genetically homogeneous. We discuss the pertinent nosology of the syndrome.
Beare-Stevenson syndrome (BSS) is a rare autosomal-dominant condition characterized by cutis gyrata, craniosynostosis, acanthosis nigricans, anogenital anomalies, and a prominent umbilical stump. In 1996, two mutations in the fibroblast growth factor receptor 2 gene were found to cause this syndrome
, thereby including BSS in the fibroblast growth factor receptor gene-related craniosynostosis spectrum. Until now, 12 patients with fibroblast growth factor receptor 2 gene-related BSS have been described. We report what is to our knowledge the first 2 Dutch patients with this syndrome, both caused by the mutation Tyr375Cys in the fibroblast growth factor receptor 2 gene. The patients exhibited a simplified gyral pattern, an abnormal posterior fossa, and an abnormal hippocampus on cranial magnetic resonance imaging. We discuss the clinical and radiologic findings in fibroblast growth factor receptor 2 gene-related BSS.
We have analysed 81 families with a history of breast and/or ovarian cancer for the presence of germline mutations in BRCA2 with a number of different mutation screening techniques. The protein truncation test (PTT) for exons 10 and 11 detected four different frame-shifting mutations in six of these
families. Four of the remaining 75 families had given positive linkage evidence for being due to BRCA2. In these families the entire coding region was analysed by single-strand conformational polymorphism, leading to the detection of a non-sense and a splice-site mutation in two of them. While these studies were in progress, Southern analysis of BRCA1 revealed that in our study-population of 81 families, 15 families were segregating either the exon 13 or exon 22 deletion in BRCA1 (Petrij-Bosch et al (1997) Nat Genet 17: 341-345). This prompted us to examine BRCA2 in the remaining 58 families by Southern analysis, using two different restriction enzymes. No aberrations were found in the restriction patterns. Thus, contrary to BRCA1, large genomic rearrangements within the BRCA2 gene do not represent a major mutation mechanism among Dutch breast cancer families.
Usher syndrome type II (USH2) is characterised by moderate to severe high-frequency hearing impairment, progressive visual loss due to retinitis pigmentosa and intact vestibular responses. Three loci are known for USH2, however, only the gene for USH2a (USH2A) has been identified. Mutation analysis
of USH2A was performed in 70 Dutch USH2 families. Ten mutations in USH2A were detected, of which three are novel, c.949C>A, c.2242C>T (p.Gln748X) and c.4405C>T (p.Gln1468X). Including 9 previously published Dutch USH2a families, estimates of the prevalence of USH2a in the Dutch USH2 population were made. Mutations were identified in 62% of the families. In 28% both mutated alleles were identified, whereas in 34% the mutation in only one allele was found. It is estimated that about 28% of the Dutch USH2 families have a different causative gene. Analysis of deduced haplotypes suggests that c.1256G>T (p.Cys419Phe) is a Dutch ancestral mutation, occurring in 16% of the alleles.
Mutations in the progranulin (PGRN) gene have recently been identified in frontotemporal lobar degeneration with ubiquitin inclusions linked to chromosome 17q21. We report here the finding of two novel frameshift mutations and three possible pathogenic missense mutations in the PGRN gene. Furthermo
re, we determined the frequency of PGRN mutations in familial cases recruited from a large population-based study of frontotemporal lobar degeneration carried out in The Netherlands.
BACKGROUND: Fanconi anemia (FA) (OMIM #227650) is a rare hereditary disease characterized by genomic instability. The clinical phenotype involves malformations, bone marrow failure, and cancer predisposition. Genetic heterogeneity is a remarkable feature of FA; at least 22 FANC genes are
known to cooperate in a unique FA/BRCA repair pathway. A common rule on the mutations found in these genes is allelic heterogeneity, except for mutations known to have arisen from a founder effect like the FANCC c.67delG in the Dutch Mennonite Community. Here, we present an 11-year-old male patient, member of the Mennonite Community of Tamaulipas México, with a clinical and cytogenetic diagnosis of FA. METHOD: Chromosome fragility test was performed in all siblings. Genomic DNA was obtained from peripheral blood samples. Sanger sequencing was used to identify the FANCC c.67delG mutation (NC_000009.11(NM_000136.2):c.67delG p.(Asp23IlefsTer23)) and its accompanying haplotype. RESULTS: The FANCC c.67delG mutation in 13 members of his family confirmed a FA diagnosis in two of his siblings and identified heterozygous carriers. Haplotype analysis supports that in this family, FA is caused by the founder mutation that initially appeared in Mennonite Dutch and followed this population's migrations through Canada and further to Mexico. CONCLUSION: The identification of the FANCC c.67delG mutation in this family not only allows proper genetic counseling, but it also grants the possibility to raise awareness of FA risk among the Mennonite community living in Mexico.
van den Berg L, etal., Obesity (Silver Spring). 2011 Mar;19(3):604-11. doi: 10.1038/oby.2010.259. Epub 2010 Oct 21.
The most common monogenic form of obesity is caused by mutations in the gene encoding the melanocortin-4 receptor (MC4R). We have screened the MC4R coding sequence in 291 patients of a Dutch outpatient pediatric obesity clinic. We analyzed the minimal promoter r
egion of the gene in a random subgroup of 217 children. Our aims were (i) to determine the frequency of MC4R mutations in a cohort of Dutch clinically obese children and (ii) to search for mutations in the promoter of the gene. Eleven MC4R coding variants were detected. Five children had mutations that have been shown to affect receptor function by other research groups (p.Y35X, p.I251fs, p.G231S). These children did not have earlier onset of obesity or higher BMI-SDS than the remainder of the cohort. One child had a novel nonsynonymous coding mutation (p.L304F). This variant showed a markedly decreased cell surface expression in in vitro experiments and is thus expected to be pathogenic. We detected 12 variants in the MC4R flanking regions. Five of these were not previously described (c.-1101C>T, c.-705A>T, c.-461A>G, c.-312T>C, c.-213A>G). We investigated these mutations by family studies and a bioinformatic approach. We conclude that rare heterozygous mutations in the coding sequence of MC4R account for some severe obesity cases in the Dutch population. These patients are difficult to recognize in a clinical setting. We generated a list of all MC4R variants that were described in the literature so far, which can aid the interpretation of mutations found in a diagnostic setting.
OBJECTIVE: We report a novel lamin A/C (LMNA) mutation, p.Glu223Lys, in a family with extensive atherosclerosis, diabetes mellitus and steatosis hepatis. METHODS: Sequence analysis of LMNA (using Alamut version 2.2), co-segregation analysis, electron microscopy, extensive phenotypic evaluation of t
he mutation carriers and literature comparison were used to determine the loss of function of this mutation. RESULTS: The father of three siblings died at the age of 45 years. The three siblings and the brother and sister of the father were referred to the cardiovascular genetics department, because of the premature atherosclerosis and dysmorphic characteristics observed in the father at autopsy. The novel LMNA mutation, p.Glu223Lys, was identified in the proband and his two sons. Clinical evaluation revealed atherosclerosis, insulin resistance and hypertension in the proband and dyslipidemia and hepatic steatosis in all the patients with the mutation. CONCLUSION: Based on the facts that in silico analysis predicts a possibly pathogenic mutation, the mutation co-segregates with the disease, only fibroblasts from mutation carriers show nuclear blebbing and a similar phenotype was reported to be due to missense mutations in LMNA we conclude that we deal with a pathogenic mutation. We conclude that the phenotype is similar to Dunnigan-type familial partial lipodystrophy.
BACKGROUND: Fabry disease (OMIM 301500) is an X-linked lysosomal storage disorder with characteristic vascular, renal, cardiac and cerebral complications. Globotriaosylceramide (Gb(3)) accumulates in Fabry patients as a result of alpha-galactosidase A deficiency. The phenotypic variability is high,
but the relationship between clinical symptoms in individual Fabry patients has not been uniformly documented. Also, the relation between the most prominent biochemical abnormalities, elevated Gb(3) levels in plasma and urine, and clinical symptoms is not firmly established. METHODS: Clinical and biochemical characteristics of 96 (25 deceased) Dutch Fabry patients were collected retrospectively and before the initiation of enzyme therapy. RESULTS: Clinical assessment revealed that median life expectancy was 57 years for male and 72 years for female patients. Cerebral complications, acroparaesthesias and gastrointestinal complications, but not cardiac and auditory complications, were all seen more frequently in male than female patients. Glomerular filtration rate (GFR) was highly variable in male patients, including 2 patients with GFR < 30 ml/min, but median GFR did not differ between males and females (103 and 101 ml/min, respectively). Hyperfiltration was more frequently observed in the female patient group. Microalbuminuria was present in 60% of males and 45% of females. No specific pattern of combined symptoms existed except for a relationship between left ventricular hypertrophy (LVH) and cerebral complications (males 36%, females 32%), or proteinuria (males 35%, females 31%). Gb(3) was found to be more elevated in plasma samples from male (n = 26; median 6.27 micromol/L (1.39-9.74)) than female Fabry patients (n = 37; median 2.16 (0.77-4.18)). This was also observed for urinary Gb(3): males (n = 22) median 1851 nmol/24 h (40-3724); females (n = 29) median 672 (86-2052). Plasma and urinary Gb(3) levels correlated with each other in both males (r = 0.4, p = 0.05) and females (r = 0.4, p = 0.03), but no correlation between elevated Gb(3) levels and clinical symptoms could be detected. CONCLUSION: Analysis of the characteristics of the Dutch Fabry cohort has revealed that a limited relationship between various disease manifestations exists and that individual symptoms do not correlate with elevated urinary or plasma Gb(3) levels, limiting their value as surrogate disease markers.
Kruit A, etal., Respiration. 2006;73(5):623-33. Epub 2006 Jan 27.
BACKGROUND: Chymase is released from mast cells following activation. Evidence suggests that chymase plays an important role in tissue injury and remodeling of the lungs, heart and skin. OBJECTIVE: We postulated that chymase gene (CMA1) polymorphisms are associated with pulmonary fibrosis in Dut
tyle='font-weight:700;'>Dutch and with cardiac and skin involvement in Japanese sarcoidosis patients. PATIENTS AND METHODS: Dutch (n = 153) and Japanese (n = 122) sarcoidosis patients with controls (Dutch, n = 309; Japanese, n = 111) were studied. Pulmonary involvement in Dutch patients as well as clinical manifestations in Japanese patients was evaluated for association with five CMA1 polymorphisms. RESULTS: The CMA1 polymorphisms were not associated with disease susceptibility in either population, or with radiographic evolution in the Dutch or with cardiac or skin involvement in the Japanese patients. The -526 T allele was associated with a lower iVC in Dutch patients. CONCLUSIONS: The CMA1 polymorphisms studied do not contribute to disease susceptibility in Japanese or Dutch sarcoidosis patients. CMA1 polymorphisms do not influence radiographic evolution in Dutch sarcoidosis patients, nor do they predispose to cardiac or skin involvement in Japanese patients. However, the association between CMA1 -526 C/T and iVC in the Dutch patients suggests that chymase may modify the functional outcome of pulmonary sarcoidosis.
BACKGROUND: Asthma and allergic phenotypes are complex genetic diseases with known linkage to chromosome 5q. This region has many candidate genes, including serine protease inhibitor Kazal type 5 (SPINK5), which has been associated with asthma and atopic dermatitis in family-based studies
of children with atopic dermatitis. OBJECTIVE: We sought to investigate whether single nucleotide polymorphisms in SPINK5 are associated with asthma, atopic phenotypes, and atopic dermatitis. METHODS: We investigated whether single nucleotide polymorphisms in SPINK5 (ie, -785 A/G, Asn368Ser, and Lys420Glu) are associated with asthma, atopic phenotypes, and atopic dermatitis in 200 families ascertained by a proband with asthma (nonaffected spouses served as a matched control population) and an independent set of 252 trios with asthma. RESULTS: We found no association with asthma, atopic phenotypes, and atopic dermatitis after correction for multiple testing. CONCLUSION: The negative results in this study suggest that SPINK5 is not associated with asthma or atopic phenotypes in individuals ascertained by a proband with asthma. This is consistent with the finding that SPINK5 is not expressed in the lung. Because our patients were ascertained for asthma, a role of SPINK5 in atopic dermatitis cannot be excluded.
de Vries Y, etal., Anemia. 2012;2012:865170. doi: 10.1155/2012/865170. Epub 2012 Jun 4.
Fanconi anemia (FA) is a recessive DNA instability disorder associated with developmental abnormalities, bone marrow failure, and a predisposition to cancer. Based on their sensitivity to DNA cross-linking agents, FA cells have been assigned to 15 complementation groups, and the associated genes hav
e been identified. Founder mutations have been found in different FA genes in several populations. The majority of Dutch FA patients belongs to complementation group FA-C. Here, we report 15 patients of Dutch ancestry and a large Canadian Manitoba Mennonite kindred carrying the FANCC c.67delG mutation. Genealogical investigation into the ancestors of the Dutch patients shows that these ancestors lived in four distinct areas in The Netherlands. We also show that the Dutch and Manitoba Mennonite FANCC c.67delG patients share the same haplotype surrounding this mutation, indicating a common founder.
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS: MIM 270550) is a neurodegenerative disorder characterized by early-onset cerebellar ataxia with spasticity and peripheral neuropathy. This disorder, considered to be rare, was first described in the late seventies among French Canadi
ans in the isolated Charlevoix-Saguenay region of Quebec. Nowadays, it is known that the disorder is not only limited to this region but occurs worldwide. Our objective was to identify cases of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) in Dutch patients with recessive early-onset cerebellar ataxia by sequencing the complete SACS gene. In a Dutch cohort of 43 index patients with ataxia onset before age 25, we identified 16 index patients (total 23 patients) with mutations in the SACS gene. Nine of them had homozygous mutations, and seven of them had compound heterozygous mutations. Retrospectively, the phenotype of patients carrying mutations was remarkably uniform: cerebellar ataxia with onset before age 13 years, lower limb spasticity and sensorimotor axonal neuropathy, and cerebellar (vermis) atrophy on magnetic resonance imaging, consistent with the core ARSACS phenotype previously described. The high rate of mutations (37%) identified in this cohort of Dutch patients suggests that ARSACS is substantially more frequent than previously estimated. We predict that the availability of SACS mutation analysis as well as an increasing awareness of the characteristic ARSACS phenotype will lead to the diagnosis of many additional patients, possibly even at a younger age.
Bakker SC, etal., Am J Med Genet B Neuropsychiatr Genet. 2005 Jan 5;132B(1):50-2.
Recent meta-analyses have indicated that the dopamine transporter gene (DAT1) and the dopamine receptor genes D4 (DRD4) and D5 (DRD5) are associated with attention-deficit hyperactivity disorder (ADHD), although single studies frequently failed to show significant association. In a family-based samp
le of 236 Dutch children with ADHD, we have investigated the previously described variable number of tandem repeat (VNTR) polymorphisms and two additional microsatellites at the DAT1 and DRD4 loci. DRD5 was investigated using the microsatellite that was previously found to be associated. Transmission disequilibrium tests (TDTs) did not show preferential transmission of alleles or two-marker haplotypes to affected offspring. These data suggest that DAT1, DRD4, and DRD5 do not contribute substantially to ADHD in the Dutch population.
Howard TD, etal., Am J Hum Genet. 2002 Jan;70(1):230-6. Epub 2001 Nov 14.
Asthma is a common respiratory disease that is characterized by variable airways obstruction caused by acute and chronic bronchial inflammation; associated phenotypes include bronchial hyperresponsiveness (BHR), elevated total serum immunoglobulin E (IgE) levels, and skin tests positive to common al
lergens. Binding of interleukin-13 (IL13) or interleukin-4 (IL4) to the IL4 receptor (IL4R) induces the initial response for Th2 lymphocyte polarization. Both IL13 and IL4 are produced by Th2 cells and are capable of inducing isotype class-switching of B-cells to produce IgE after allergen exposure. These cytokines also share a common receptor component, IL4R alpha. We have investigated five IL4RA single-nucleotide polymorphisms in a population of Dutch families ascertained through a proband with asthma. By considering the probands and their spouses as an unrelated sample, we observed significant associations of atopy and asthma-related phenotypes with several IL4RA polymorphisms, including S478P and total serum IgE levels (P=.0007). A significant gene-gene interaction between S478P in IL4RA and the -1111 promoter variation in IL13, previously shown to be associated with BHR (P=.003), was detected. Individuals with the risk genotype for both genes were at almost five times greater risk for the development of asthma compared to individuals with both non-risk genotypes (P=.0004). These data suggest that variations in IL4RA contribute to elevated total serum IgE levels, and interaction between IL4RA and IL13 markedly increases an individual's susceptibility to asthma.
Noonan syndrome (NS) is an autosomal dominant disorder characterized by facial dysmorphisms, short stature and congenital heart defects. The disorder is genetically heterogeneous and shows clinical overlap with other RASopathies. These syndromes are caused by mutations in a variety of genes leading
to dysregulation of the RAS-MAPK pathway: PTPN11, KRAS, SOS1, RAF1, CBL, SHOC2, NRAS, BRAF, MAP2K1, MAP2K2, HRAS, NF1 and SPRED1. In this study, we conduct a genotype-phenotype analysis of 33 patients with a clinical diagnosis of NS without a PTPN11 mutation. Mutation analysis of the genes involved in RASopathies was performed, except for NF1 and SPRED1. In 14 (42%) NS patients, a mutation was found, 7 (21%) had a mutation in SOS1, 3 (9%) in RAF1 and 1 (3%) in KRAS, MAP2K2, BRAF and SHOC2 each. The phenotype of these mutation-positive cases corresponded to that described in the literature. In the cases with a BRAF and MAP2K2 mutation, the diagnosis cardio-facio-cutaneous syndrome was made. The patient with the SHOC2 mutation had features compatible with 'Noonan-like syndrome with loose anagen hair'. Three major clinical features of NS - a typical face, short stature and a pulmonary valve stenosis - were less frequently present in the group without a mutation. Missense mutations in genes encoding proteins of the RAS-MAPK pathway cause NS. The 3 major clinical features of NS were less frequently present in the mutation-negative patients, which stresses the importance of the syndrome-specific symptoms of the face, heart and short stature in NS. However, all mutation-negative cases met the NS criteria, indicating that the involvement of novel genes is to be expected.
Petrij-Bosch A, etal., Nat Genet. 1997 Nov;17(3):341-5.
To date, more than 300 distinct small deletions, insertions and point mutations, mostly leading to premature termination of translation, have been reported in the breast/ovarian-cancer susceptibility gene BRCA1. The elevated frequencies of some mutations in certain ethnic subpopulations are caused
by founder effects, rather than by mutation hotspots. Here we report that the currently available mutation spectrum of BRCA1 has been biased by PCR-based mutation-screening methods, such as SSCP, the protein truncation test (PTT) and direct sequencing, using genomic DNA as template. Three large genomic deletions that are not detected by these approaches comprise 36% of all BRCA1 mutations found in Dutch breast-cancer families to date. A 510-bp Alu-mediated deletion comprising exon 22 was found in 8 of 170 breast-cancer families recruited for research purposes and in 6 of 49 probands referred to the Amsterdam Family Cancer Clinic for genetic counselling. In addition, a 3,835-bp Alu-mediated deletion encompassing exon 13 was detected in 4 of 170 research families, while an deletion of approximately 14 kb was detected in a single family [corrected]. Haplotype analyses indicated that each recurrent deletion had a single common ancestor.
An adult autochthonous Dutch patient who had exhibited severe perinatal anaemia, with partial recovery a few months after birth, was studied for the presence of beta-thalassaemia. Southern blotting showed that the patient was heterozygous for a novel deletion i
n the beta-globin gene cluster, leaving the beta-gene intact. Inverse polymerase chain reaction was used to determine the breakpoint sequence. The deletion removed 112 kb starting upstream of the HOR5'b6 gene to the second intron of the Agamma-globin gene, including the locus control region. The breakpoint fragment identified a 13-bp orphan sequence not present at either side of the breakpoint.
Rona G, etal., FEBS J. 2014 Dec;281(24):5463-78. doi: 10.1111/febs.13086. Epub 2014 Oct 25.
Nucleocytoplasmic trafficking of large macromolecules requires an active transport machinery. In many cases, this is initiated by binding of the nuclear localization signal (NLS) peptide of cargo proteins to importin-alpha molecules. Fine orchestration of nucleocytoplasmic trafficking is of particu
larly high importance for proteins involved in maintenance of genome integrity, such as dUTPases, which are responsible for prevention of uracil incorporation into the genome. In most eukaryotes, dUTPases have two homotrimeric isoforms: one of these contains three NLSs and is present in the cell nucleus, while the other is located in the cytoplasm or the mitochondria. Here we focus on the unusual occurrence of a pseudo-heterotrimeric dUTPase in Drosophila virilis that contains one NLS, and investigate its localization pattern compared to the homotrimeric dUTPase isoforms of Drosophila melanogaster. Although the interaction of individual NLSs with importin-alpha has been well characterized, the question of how multiple NLSs of oligomeric cargo proteins affect their trafficking has been less frequently addressed in adequate detail. Using the D. virilis dUTPase as a fully relevant physiologically occurring model protein, we show that NLS copy number influences the efficiency of nuclear import in both insect and mammalian cell lines, as well as in D. melanogaster and D. virilis tissues. Biophysical data indicate that NLS copy number determines the stoichiometry of complexation between importin-alpha and dUTPases. The main conclusion of our study is that, in D. virilis, a single dUTPase isoform efficiently reproduces the cellular dUTPase distribution pattern that requires two isoforms in D. melanogaster.
Xu Y, etal., Clin Cancer Res. 2006 Jul 1;12(13):4072-9.
PURPOSE: Prostatic dihydrotestosterone (DHT) concentration is regulated by precursors from systemic circulation and prostatic enzymes of androgen metabolism, particularly 5alpha-reductases (i.e., SRD5A1 and SRD5A2). Therefore, the levels of expression SRD5A1 and SRD5A2 and the antiprostatic cancer g
rowth response to finasteride, a selective SRD5A2 inhibitor, versus the dual SRD5A1 and SRD5A2 inhibitor, dutasteride, were compared. EXPERIMENTAL DESIGN: Real-time PCR and enzymatic assays were used to determine the levels of SRD5A1 and SRD5A2 in normal versus malignant rat and human prostatic tissues. Rats bearing the Dunning R-3327H rat prostate cancer and nude mice bearing LNCaP or PC-3 human prostate cancer xenografts were used as model systems. Tissue levels of testosterone and DHT were determined using liquid chromatography-mass spectrometry. RESULTS: Prostate cancer cells express undetectable to low levels of SRD5A2 but elevated levels of SRD5A1 activity compared with nonmalignant prostatic tissue. Daily oral treatment of rats with the SRD5A2 selective inhibitor, finasteride, reduces prostate weight and DHT content but did not inhibit R-3327H rat prostate cancer growth or DHT content in intact (i.e., noncastrated) male rats. In contrast, daily oral treatment with even a low 1 mg/kg/d dose of the dual SRD5A1 and SRD5A2 inhibitor, dutasteride, reduces both normal prostate and H tumor DHT content and weight in intact rats while elevating tissue testosterone. Daily oral treatment with finasteride significantly (P < 0.05) inhibits growth of LNCaP human prostate cancer xenografts in intact male nude mice, but this inhibition is not as great as that by equimolar oral dosing with dutasteride. This anticancer efficacy is not equivalent, however, to that produced by castration. Only combination of dutasteride and castration produces a greater tumor inhibition (P < 0.05) than castration monotherapy against androgen-responsive LNCaP cancers. In contrast, no response was induced by dutasteride in nude mice bearing androgen-independent PC-3 human prostatic cancer xenografts. CONCLUSIONS: These results document that testosterone is not as potent as DHT but does stimulate prostate cancer growth, thus combining castration with dutasteride enhances therapeutic efficacy.
Zafarmand MH, etal., Hypertension. 2008 Jun;51(6):1665-70. Epub 2008 May 5.
The Gly460Trp variant of the alpha-adducin gene has been associated with renal sodium retention and salt-sensitive hypertension. Independent of blood pressure, salt sensitivity has been related to cerebrovascular events. We studied the risk of stroke, coronary heart disease (CHD), and myocardial inf
arction (MI) associated with the alpha-adducin variant and examined the extent to which this risk is modified by the presence of hypertension. We performed a case-cohort study in a prospective cohort of 15,236 initially healthy Dutch women. We applied a Cox proportional hazards model with an estimation procedure adapted for case-cohort designs to study the relation of the polymorphism and CHD (n=210), MI (n=71), any stroke (n=74), and ischemic stroke (n=49). Subjects with the Gly460Trp variant had a 2.8 times higher risk of stroke (95% confidence intervals [CI] 1.3 to 5.8) under the dominant genetic model, which did not attenuate after adjustment. The same pattern was found under per-allele comparison. Risk of ischemic stroke in the variant allele carriers was 3.9 times higher than in subjects with the common genotype (95% CI 1.7 to 8.6) using dominant inheritance model. The same patterns were found under per-allele comparison. CHD and MI were not related to the variant. The risk of ischemic stroke was more pronounced among women with systolic hypertension (10.9; 95% CI 3.6 to 31.5). The findings in this prospective study in a population based cohort of Dutch women strongly suggest that presence of the alpha-adducin Gly460Trp polymorphism increases the risk of stroke. This risk is particularly elevated in the presence of systolic hypertension.
Germline mutations in the ATM gene are responsible for the autosomal recessive disorder ataxia-telangiectasia (A-T). In our study, we have determined the ATM mutation spectrum in 19 classical A-T patients, including some immigrant populations, as well as 12 of Dut
n>ch ethnic origin. Both the protein truncation test (PTT) and the restriction endonuclease fingerprinting (REF) method were used and compared for their detection efficiency, identifying 76% and 60% of the mutations, respectively. Most patients were found to be compound heterozygote. Seventeen mutations were distinct, of which 10 were not reported previously. Mutations are small deletions or point mutations frequently affecting splice sites. Moreover, a 16.7-kb genomic deletion of the 3' end of the gene, most likely a result of recombination between two LINE elements, was identified. The most frequently found mutation, identified in three unrelated Turkish A-T individuals, was previously described to be a Turkish A-T founder mutation. The presence of a founder mutation among relatively small ethnic population groups in Western Europe could indicate a high carrier frequency in such communities. In patients of Dutch ethnic origin, however, no significant founder effect could be identified. The observed genetic heterogeneity including the relative high percentage of splice-site mutations had no reflection on the phenotype. All patients manifested classical A-T and increased cellular radioresistant DNA synthesis.
van Beelen E, etal., Ear Hear. 2016 Jan-Feb;37(1):103-11. doi: 10.1097/AUD.0000000000000217.
OBJECTIVES: Mutations in EYA4 can cause nonsyndromic autosomal dominant sensorineural hearing impairment (DFNA10) or a syndromic variant with hearing impairment and dilated cardiomyopathy. A mutation in EYA4 was found in a Dutch family, causing DFNA10. This stud
y is focused on characterizing the hearing impairment in this family. DESIGN: Whole exome sequencing was performed in the proband. In addition, peripheral blood samples were collected from 23 family members, and segregation analyses were performed. All participants underwent otorhinolaryngological examinations and pure-tone audiometry, and 12 participants underwent speech audiometry. In addition, an extended set of audiometric measurements was performed in five family members to evaluate the functional status of the cochlea. Vestibular testing was performed in three family members. Two individuals underwent echocardiography to evaluate the nonsyndromic phenotype. RESULTS: The authors present a Dutch family with a truncating mutation in EYA4 causing a mid-frequency hearing impairment. This mutation (c.464del) leads to a frameshift and a premature stop codon (p.Pro155fsX). This mutation is the most N-terminal mutation in EYA4 found to date. In addition, a missense mutation, predicted to be deleterious, was found in EYA4 in two family members. Echocardiography in two family members revealed no signs of dilated cardiomyopathy. Results of caloric and velocity step tests in three family members showed no abnormalities. Hearing impairment was found to be symmetric and progressive, beginning as a mid-frequency hearing impairment in childhood and developing into a high-frequency, moderate hearing impairment later in life. Furthermore, an extended set of audiometric measurements was performed in five family members. The results were comparable to those obtained in patients with other sensory types of hearing impairments, such as patients with Usher syndrome type IIA and presbyacusis, and not to those obtained in patients with (cochlear) conductive types of hearing impairment, such as DFNA8/12 and DFNA13. CONCLUSIONS: The mid-frequency hearing impairment in the present family was found to be symmetric and progressive, with a predominantly childhood onset. The results of psychophysical measurements revealed similarities to other conditions involving a sensory type of hearing impairment, such as Usher syndrome type IIA and presbyacusis. The study results suggest that EYA4 is expressed in the sensory cells of the cochlea. This phenotypic description will facilitate counseling for hearing impairment in DFNA10 patients.
Martin MA, etal., Ann Hum Genet. 2004 Jan;68(Pt 1):17-22.
We report on 8 Dutch patients with McArdle's disease from 6 unrelated families. Molecular analysis revealed the presence of four previously described mutations: the common R49X mutation, the IVS14+1G>A mutation and the recently reported R269X and Y84X nonsense
mutations; and two new molecular defects: a missense mutation R138W in the homozygous state in two siblings, and a frameshift mutation c.1797delT. This first genetic study of patients from The Netherlands with McArdle's disease confirms that the R49X mutation is also the most common in Dutch patients, and that there is genetic heterogeneity within this population. Moreover, our data support the hypothesis that the Y84X mutation is a relatively frequent mutation in McArdle's patients with a Central European background, and expand the already crowded map of mutations within the PYGM gene responsible for McArdle's disease.
Yue W, etal., Clin Cancer Res. 2007 Aug 1;13(15 Pt 1):4336-44. doi: 10.1158/1078-0432.CCR-07-0015.
PURPOSE: The goal of this study is to identify novel genes frequently silenced by promoter hypermethylation in lung cancer. EXPERIMENTAL DESIGNS: Bioinformatic analysis was done to identify candidate genes significantly down-regulated in lung cancer. The effects of DNA methyltra
nsferase inhibitor 5-aza-2'-deoxycytidine on the expression of the candidate genes were determined. Methylated CpG sites in the promoters of the candidate genes were identified using bisulfite DNA sequencing. Methylation-specific PCR was developed and used to analyze DNA methylation in cell lines and clinical specimen. Pathologic and functional analyses were done to study the role of one candidate gene, receptor activity-modifying protein 2 (RAMP2), in suppressing lung cancer cell growth. RESULTS: Among 54 candidate genes down-regulated in lung cancer, 31 were found to contain CpG islands in their promoters. Six of these 31 genes could be reactivated by 5-aza-2'-deoxycytidine in at least four of six lung cancer cell lines analyzed. Promoter hypermethylation of RAMP2, epidermal growth factor-containing fibulin-like extracellular matrix protein 1, and deleted in U Twenty Twenty cells was detected in 36% to 77% of 22 lung cancer cell lines and in 38% to 50% of 32 primary lung tumors, whereas hypermethylathion of these genes was rarely found in the matched normal samples. The methylation frequencies of these genes in lung cancer were similar to those of commonly used methylation markers, such as RAS association domain family protein 1A, p16, and methylguanine-DNA methyltransferase. Immunohistochemistry showed that RAMP2 was down-regulated in a majority of lung tumors, and RAMP2 down-regulation was correlated with high tumor grade. Ectopic expression of RAMP2 inhibited lung cancer cell growth and caused apoptotic cell death. Knockdown of RAMP2 by RNA interference stimulated cell proliferation. CONCLUSIONS: Studying the newly identified genes may provide new insight into lung tumorigenesis. These genes might be useful as molecular markers of lung cancer.
Santos RL, etal., Int J Pediatr Otorhinolaryngol. 2005 Feb;69(2):165-74.
OBJECTIVE: Despite the identification of mutations in the connexin 26 (GJB2) gene as the most common cause of recessive nonsyndromic hearing loss, the pattern of hearing impairment with these mutations remains inconsistent. Recently a deletion encompassing the GJB6 gene was identified and hypothesiz
ed to also contribute to hearing loss. We hereby describe the hearing impairment in Dutch patients with biallelic connexin 26 (GJB2) and GJB2+connexin 30 (GJB6) mutations. METHODS: The audiograms of patients who were screened for GJB2 and GJB6 mutations were analysed retrospectively. Standard statistical testing was done for symmetry and shape, while repeated measurement analysis was used to assess the relation between mutation and severity. Progression was also studied via linear regression analysis. RESULTS: Of 222 hearing-impaired individuals, 35 exhibited sequence variations; of these 19 had audiograms for study. Hearing loss in patients with biallelic "radical" (i.e. deletions, nonsense and splice site) mutations was significantly worse than in the wild type and heterozygotes (SAS proc GENMOD, p=0.013). The presence of at least one missense mutation in compound heterozygotes tends to lead to better hearing thresholds compared to biallelic radical mutations (p=0.08). One patient with the [35delG]+[del(GJB6-D13S1830)] genotype was severely impaired. Non-progressive hearing impairment was demonstrated in five 35delG homozygotes in individual longitudinal analyses. However a patient with the [299A>C]+[416G>A] genotype showed significant threshold progression in the lower frequencies. Findings on asymmetry and shape were inconclusive. CONCLUSIONS: Our data support the hypothesis that severity is a function of genotype and its effect on the amino acid sequence. A bigger cohort is required to establish non-progressivity more definitively.
Within a group of 76 sporadic/autosomal recessive limb girdle muscular dystrophy (LGMD) patients we tried to identify those with LGMD type 2C-E. Muscle biopsy specimens of 40 index patients, who had 22 affected sibs, were analyzed immuno-histochemically for the presence of three subunits: alpha-, b
eta-, and gamma-sarcoglycans. Abnormal sarcoglycan expression was established in eight patients, with six affected sibs. In one patient gamma-sarcoglycan was absent, and both alpha- and beta-sarcoglycans were reduced. In the remaining seven patients gamma-sarcoglycan was (slightly) reduced, and alpha- and beta-sarcoglycans were absent or reduced. By DNA sequencing mutations were detected in one of the three sarcoglycan genes in all eight cases. Three patients had mutations in the alpha-, three in the beta-, and two in the gamma-sarcoglycan gene. The patients with sarcoglycanopathy comprised the more severely affected cases (P=0.04). In conclusion, sarcoglycanopathy was identified in 23 % (14/62) of the autosomal recessive LGMD patients.
Fetal akinesia deformation sequence (FADS) refers to a clinically and genetically heterogeneous group of disorders with congenital malformations related to impaired fetal movement. FADS can result from mutations in CHRNG, CHRNA1, CHRND, DOK7 and RAPSN; however, these genes only account for a minorit
y of cases. Here we identify MUSK as a novel cause of lethal FADS. Fourteen affected fetuses from a Dutch genetic isolate were traced back to common ancestors 11 generations ago. Homozygosity mapping in two fetuses revealed MUSK as a candidate gene. All tested cases carried an identical homozygous variant c.1724T>C; p.(Ile575Thr) in the intracellular domain of MUSK. The carrier frequency in the genetic isolate was 8%, exclusively found in heterozygous carriers. Consistent with the established role of MUSK as a tyrosine kinase that orchestrates neuromuscular synaptogenesis, the fetal myopathy was accompanied by impaired acetylcholine receptor clustering and reduced tyrosine kinase activity at motor nerve endings. A functional assay in myocytes derived from human fetuses confirmed that the variant blocks MUSK-dependent motor endplate formation. Taken together, the results strongly support a causal role of this founder mutation in MUSK, further expanding the gene set associated with FADS and offering new opportunities for prenatal genetic testing.
Nielsen M, etal., Eur J Hum Genet. 2007 Oct;15(10):1034-42. Epub 2007 Jun 13.
Partial and whole gene deletions represent a large proportion (4-33%) of the APC mutations found in polyposis patients, who previously had negative test results. The genotype-phenotype correlations for these APC deletions have not been studied in detail. We aimed to assess the number of germ line
APC deletions in Dutch polyposis patients, to describe the clinical phenotype(s), and to review the current literature. We screened 296 index patients with polyposis, who previously had negative test results for APC or MUTYH mutations, for germ line APC gene deletions using Multiplex Ligation-dependent Probe Amplification. APC deletions were identified in 19 polyposis patients; seven had a whole gene deletion, nine had a deletion involving two or more exons, and three had single exon deletions. Most of the deletion families (83%) displayed a classic familial adenomatous polyposis (FAP) phenotype (100-2000 adenomas). We saw no patients with APC deletions and a severe phenotype (ie >2000 polyps); on the contrary, two families carrying a deletion of exons 7-13 and one family with a deletion of exons 1-5 showed a distinctly attenuated FAP phenotype. APC deletions were found in a considerable proportion of polyposis patients previously tested negative for APC or MUTYH (6%, 19/296) and represent 8% of all APC mutations found at our clinics (19/242). Methods to identify such deletions should therefore be included in routine germ line APC mutation analysis. While most total and partial APC deletions lead to a classic FAP phenotype, specific (in-frame) deletions may lead to an attenuated polyposis phenotype.
A novel DFNA5 mutation was found in a Dutch family, of which 37 members were examined. A nucleotide substitution was identified in the splice acceptor site of intron 7, leading to skipping of exon 8 in part of the transcripts. The mutation was found in 18 indiv
iduals. Sensorineural hearing impairment was non-syndromic and symmetric. In early life, presumably congenitally, hearing impairment amounted to 30 dB in the high frequencies. Progression was most pronounced at 1 kHz (1.8 dB/year). Speech recognition was relatively good with a phoneme score of about 50% at the age of 70. Onset age was 37 years, and recognition deteriorated by 1.3% per year. The recognition score deteriorated by 1.0% per decibel threshold increase from a mean pure-tone average (PTA at 1, 2 and 4 kHz) of 63 dB onwards. Vestibular function was generally normal. The second mutation identified in the DFNA5 gene results in hearing impairment, similar to that in the original DFNA5 family in terms of pure-tone thresholds, but with more favourable speech recognition.
Recently, a high prevalence of morning-types was reported among trained South African endurance athletes. Proposed explanations for this observation were that either the chronotype of these athletes is better suited to coping with the early-morning start times of endurance events in South Africa; o
r habitual early waking for training or endurance events may have conditioned the athletes to adapt and become morning-types. The South African endurance athletes also had earlier chronotypes compared to a control population of less active individuals, suggesting that individuals who are more physically active may have earlier chronotypes. However, since both the South African athlete and control groups showed an overrepresentation of morning-types compared to European and American populations, the South African climate may in part have explained this bias towards morningness. Given the latitude and climate differences between South Africa and the Netherlands, and that South African marathons typically start at about 06:30 while those in the Netherlands start later (+/-11:00), comparison of South African and Dutch marathon runners and active controls would allow for simultaneous assessment of the effects of marathon start time, degree of physical activity and climate on chronotype. Therefore, the primary aims of this study were: (i) to assess the effect of marathon start time on chronotype in marathon runners and (ii) to determine the extent to which either degree of physical activity or climate might explain the bias towards morningness observed in South African athletes and controls. A secondary aim was to determine whether any relationships exist between chronotype, PERIOD3 (PER3) variable number tandem repeat (VNTR) polymorphism genotype, habitual training habits and marathon performance. Trained male marathon runners from South Africa (n = 95) and the Netherlands (n = 90), and active but non-competitive male controls from South Africa (n = 97) and the Netherlands (n = 98) completed a questionnaire capturing demographics, training and race history, as well as the Horne-Ostberg morningness-eveningness personality questionnaire. All participants donated buccal cell samples from which genomic DNA was extracted and polymerase chain reaction analysis was used to genotype them for the PER3 VNTR polymorphism, which has previously been associated with chronotype. The main finding was that South African runners were significantly more morning-orientated than Dutch runners suggesting that participation in an endurance sport with an earlier start time may influence chronotype. Secondly, both the South African and Dutch runners were significantly more morning-orientated than their respective control groups, indicating that individuals who train for and participate in recreational endurance sport races have an earlier chronotype than physically active but non-competitive males. Thirdly, mean chronotype scores were similar between the South African and Dutch control groups, suggesting that climate does not seem to affect chronotype in these groups. Fourthly, the PER3 VNTR polymorphism distribution was similar between the four groups and was not associated with chronotype, suggesting that the difference in chronotype between the four groups in this study is not explained by the PER3 VNTR genotype. Lastly, in the South African runners group, a higher preference for mornings was associated with a better personal best half-marathon and current marathon performance.
Bet PM, etal., Pharmacogenomics J. 2016 Apr;16(2):202-8. doi: 10.1038/tpj.2015.38. Epub 2015 May 19.
The drug efflux transporter permeability glycoprotein (PGP) and cytochrome P450 (CYP) 2C19 are important for eliminating antidepressants from the brain and body. The ABCB1 gene, encoding for PGP, and CYP2C19 gene have several variants that could influence enzyme function and thereby the effect of PG
P- and 2C19-dependent antidepressants. We investigated the association of antidepressant side effect and common genetic variation in 789 antidepressant users. In PGP-dependent antidepressant users, the A-allele of the rs2032588 single-nucleotide polymorphism (SNP) was associated with a lower number of side effects after adjusting for gender, age, dosage and duration of use, (B=-0.44, q=4.6 x 10(-3)). This association was different from and absent in non-PGP-dependent antidepressant users. Other SNP associations as well as an interaction analysis between the rs2032588 SNP and the CYP2C19 SNPs were not statistically significant after adjusting for covariates and multiple comparisons. The association of rs2032588 with antidepressant side effects suggests the involvement of the ABCB1 genotype in the clinical pharmacology of PGP-dependent antidepressants.
van der Hout AH, etal., Hum Mutat. 2006 Jul;27(7):654-66.
Rapid and reliable identification of deleterious changes in the breast cancer genes BRCA1 and BRCA2 has become one of the major issues in most DNA services laboratories. To rapidly detect all possible changes within the coding and splice site determining sequences of the breast cancer genes, we esta
blished a semiautomated denaturing gradient gel electrophoresis (DGGE) mutation scanning system. All exons of both genes are covered by the DGGE scan, comprising 120 amplicons. We use a semiautomated approach, amplifying all individual amplicons with the same PCR program, after which the amplicons are pooled. DGGE is performed using three slightly different gel conditions. Validation was performed using DNA samples with known sequence variants in 107 of the 120 amplicons; all variants were detected. This DGGE mutation scanning, in combination with a PCR test for two Dutch founder deletions in BRCA1 was then applied in 431 families in which 52 deleterious changes and 70 unclassified variants were found. Fifteen unclassified variants were not reported before. The system was easily adopted by five other laboratories, where in another 3,593 families both exons 11 were analyzed by the protein truncation test (PTT) and the remaining exons by DGGE. In total, a deleterious change (nonsense, frameshift, splice-site mutation, or large deletion) was found in 661 families (16.4%), 462 in BRCA1 (11.5%), 197 in BRCA2 (4.9%), and in two index cases a deleterious change in both BRCA1 and BRCA2 was identified. Eleven deleterious changes in BRCA1 and 36 in BRCA2 had not been reported before. In conclusion, this DGGE mutation screening method for BRCA1 and BRCA2 is proven to be highly sensitive and is easy to adopt, which makes screening of large numbers of patients feasible. The results of screening of BRCA1 and BRCA2 in more than 4,000 families present a valuable overview of mutations in the Dutch population.
Peelen T, etal., Am J Hum Genet. 1997 May;60(5):1041-9.
We have identified 79 mutations in BRCA1 in a set of 643 Dutch and 23 Belgian hereditary breast and ovarian cancer families collected either for research or for clinical diagnostic purposes. Twenty-eight distinct mutations have been observed, 18 of them not prev
iously reported and 12 of them occurring more than once. Most conspicuously, a 2804delAA mutation has been found 19 times and has never been reported outside the Netherlands. A common haplotype spanning > or = 375 kb could be identified for each of the nine examined recurrent mutations, indicating the presence of multiple BRCA1 founder mutations in the Dutch population. The 2804delAA mutation has been estimated to have originated approximately 32 generations ago. No specific breast or ovarian cancer phenotype could be assigned to any of the common mutations, and the ovarian cancer incidence among 18 families with the 2804delAA mutation was heterogeneous.
Abnormalities of tumor suppressor genes (TSGs) on chromosome 3p are known to be important for the development of human lung cancers. In the present study, we investigated alterations of the Dutt1/Robo1 gene, as a possible tumor suppressor in this region, in rat
lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP). Male Wistar rats, 6-wk-old, were given 2000 ppm BHP in their drinking water for 12 wk and maintained without further treatment until killed at wk 25. A total of 12 lung adenocarcinomas were obtained and total RNAs were extracted from each for assessment of aberrant transcripts of the Dutt1/Robo1 gene by reverse transcription (RT)-polymerase chain reaction (PCR) analysis. Aberrant transcripts bearing deletions of nucleotides (nt) 55-4318, 89-4346, 605-4221, and 929-4318 were detected in four of 12 adenocarcinomas (33.3%). Loss or reduced expression of the Dutt1/Robo1 gene was not found in any of the adenocarcinomas. Genomic DNAs extracted from six adenocarcinomas for Southern blot analysis did not show any evidence of deletion or gross rearrangement of the Dutt1/Robo1 gene. These results suggest that alterations of the Dutt1/Robo1 gene may be involved in the development of some lung adenocarcinomas induced by BHP in rats.
Kruit A, etal., Sarcoidosis Vasc Diffuse Lung Dis. 2010 Jul;27(2):147-52.
BACKGROUND: The angiotensin II type 1 receptor (AT2R1) is the receptor for angiotensin II, a potent vasoconstrictor produced by ACE from angiotensin I. A recent study by Biller and colleagues revealed a gender-specific association between the AT2R1 1166 A/C gene polymorphism and disease susceptibili
ty as well as a co-dependent association between AT2R1 1166 A/C and the angiotensin-converting enzyme (ACE) insertion/deletion polymorphism on ACE levels in a group of German sarcoidosis patients. OBJECTIVE: . The aim of our study was to compare our results from Dutch Caucasian sarcoidosis patients with the results of Biller et al. DESIGN: Serum and DNA from 99 patients with sarcoidosis and from 327 healthy controls were included. The AT2R1 1166 A/C and ACE I/D polymorphisms and serum ACE levels were analyzed in all subjects. RESULTS: No significant differences were found between the genotype distributions between the sarcoidosis patients and controls. The genotype distributions for either polymorphism between genders and between patients with progressive/chronic disease and those with acute/remission type disease were not different. The ACE D allele contributed significantly to higher ACE levels. This was true for both sarcoidosis patients and controls. There was no association between the AT2R1 1166 A/C genotype and ACE levels, nor did AT2R1 modify the ACE D/I effects on ACE levels. No significant differences were observed in co-incidence of ACE and AT2R1 genotypes between patients and controls. CONCLUSION: Our study could not confirm the findings by Biller and colleagues other than the influence of the ACE I/D polymorphism on serum ACE levels in both sarcoidosis patients and controls.
Cox MG, etal., Circulation. 2011 Jun 14;123(23):2690-700. doi: 10.1161/CIRCULATIONAHA.110.988287. Epub 2011 May 23.
BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an autosomal dominant inherited disease with incomplete penetrance and variable expression. Causative mutations in genes encoding 5 desmosomal proteins are found in approximately 50% of ARVD/C index patients. Previous
genotype-phenotype relation studies involved mainly overt ARVD/C index patients, so follow-up data on relatives are scarce. METHODS AND RESULTS: One hundred forty-nine ARVD/C index patients (111 male patients; age, 49+/-13 years) according to 2010 Task Force criteria and 302 relatives from 93 families (282 asymptomatic; 135 male patients; age, 44+/-13 years) were clinically and genetically characterized. DNA analysis comprised sequencing of plakophilin-2 (PKP2), desmocollin-2, desmoglein-2, desmoplakin, and plakoglobin and multiplex ligation-dependent probe amplification to identify large deletions in PKP2. Pathogenic mutations were found in 87 index patients (58%), mainly truncating PKP2 mutations, including 3 cases with multiple mutations. Multiplex ligation-dependent probe amplification revealed 3 PKP2 exon deletions. ARVD/C was diagnosed in 31% of initially asymptomatic mutation-carrying relatives and 5% of initially asymptomatic relatives of index patients without mutation. Prolonged terminal activation duration was observed more than negative T waves in V(1) to V(3), especially in mutation-carrying relatives <20 years of age. In 45% of screened families, >/=1 affected relatives were identified (90% with mutations). CONCLUSIONS: Pathogenic desmosomal gene mutations, mainly truncating PKP2 mutations, underlie ARVD/C in the majority (58%) of Dutch index patients and even 90% of familial cases. Additional multiplex ligation-dependent probe amplification analysis contributed to discovering pathogenic mutations underlying ARVD/C. Discovering pathogenic mutations in index patients enables those relatives who have a 6-fold increased risk of ARVD/C diagnosis to be identified. Prolonged terminal activation duration seems to be a first sign of ARVD/C in young asymptomatic relatives.
de Vos A, etal., Pharmacogenomics J. 2011 Oct;11(5):359-67. doi: 10.1038/tpj.2010.39. Epub 2010 Jun 8.
Polymorphisms in genes coding for drug metabolizing enzymes, such as the cytochrome P450 enzymes CYP2C19 and CYP2D6, can lead to therapy failure and side effects. In earlier studies, the novel variant CYP2C19*17 increased metabolism of several CYP2C19 substrates. The objective of this study was to
evaluate the impact of CYP2C19*17 on the metabolism of amitriptyline (AT), citalopram (CIT), and clomipramine (CLOM). Six-hundred and seventy-eight patients were included in this study, based on availability of DNA and serum levels of parent drug and main metabolite. We investigated the relationship between CYP2C19 genotypes and metabolic parameters, including serum levels corrected for dose and metabolic ratio (MR). The CYP2C19*17 allele was significantly associated with decreased MR for CIT (CYP2C19*1/*17 mean MR=2.3, compared with CYP2C19*1/*1 mean MR=2.8) and AT (CYP2C19*17/*17 mean MR=0.8, compared with CYP2C19*1/*1 mean MR=3.7 in the CYP2D6*1/*1 subgroup). Furthermore, significant association of CYP2D6 genotype with AT, CIT, and CLOM metabolism was observed. No clear correlation was found between CYP2C19 genotype and CLOM metabolism. This study confirms the increased activity of the CYP2C19*17 allele and shows increased metabolism of drugs that are metabolized by CYP2C19, including AT and CIT. However, the clinical relevance of CYP2C19*17 is probably limited for AT, CIT, and CLOM.
Leukocytes are involved in the pathogenesis of idiopathic inflammatory myopathies (IIMs). Immunoglobulin G (IgG) receptors (FcgammaR) link the specificity of IgG to the effector functions of leukocytes. Several FcgammaR subclasses display functional polymorphisms that determine in part the vigour of
the inflammatory response. FcgammaRIIIa genotypes were differentially distributed among 100 IIM patients compared with 514 healthy controls with a significant increase of the homozygous FcgammaRIIIa-V-158 genotype (3 x 2 contingency table, chi(2) = 6.3, P = 0.04). Odds ratios (ORs) increased at the addition of each FcgammaRIIIa-V-158 allele, in particular among patients with non-specific myositis and dermatomyositis {OR 2.1 [95% confidence interval (CI) 1.1-4.3] and 2.7 (95% CI 1.1-6.4) for FcgammaRIIIa-V/F158 and FcgammaRIIIa-V/V158 genotypes, respectively, using FcgammaRIIIa-F/F158 as a reference group}. These data suggest that the FcgammaRIIIa-V-158 allele may constitute a genetic risk marker for IIM.
Brohet RM, etal., J Med Genet. 2014 Feb;51(2):98-107. doi: 10.1136/jmedgenet-2013-101974. Epub 2013 Nov 27.
BACKGROUND: BRCA1 or BRCA2 mutations confer increased risks of breast and ovarian cancer, but risks have been found to vary across studies and populations. METHODS: We ascertained pedigree data of 582 BRCA1 and 176 BRCA2 families and studied the variation in breast and ovarian cancer risks using a m
odified segregation analysis model. RESULTS: The average cumulative breast cancer risk by age 70 years was estimated to be 45% (95% CI 36 to 52%) for BRCA1 and 27% (95% CI 14 to 38%) for BRCA2 mutation carriers. The corresponding cumulative risks for ovarian cancer were 31% (95% CI 17 to 43%) for BRCA1 and 6% (95% CI 2 to 11%) for BRCA2 mutation carriers. In BRCA1 families, breast cancer relative risk (RR) increased with more recent birth cohort (p heterogeneity = 0.0006) and stronger family histories of breast cancer (p heterogeneity < 0.001). For BRCA1, our data suggest a significant association between the location of the mutation and the ratio of breast to ovarian cancer (p<0.001). By contrast, in BRCA2 families, no evidence was found for risk heterogeneity by birth cohort, family history or mutation location. CONCLUSIONS: BRCA1 mutation carriers conferred lower overall breast and ovarian cancer risks than reported so far, while the estimates of BRCA2 mutations were among the lowest. The low estimates for BRCA1 might be due to older birth cohorts, a moderate family history, or founder mutations located within specific regions of the gene. These results are important for a more accurate counselling of BRCA1/2 mutation carriers.
OBJECTIVE: HbA1c is associated with cardiovascular risk in persons without diabetes and cardiovascular risk accumulates over the life course. Therefore, insight in factors determining HbA1c from childhood onwards is important. We investigated (lifestyle) determinants of HbA1c at age 12 years and the
effects of growth on change in HbA1c and the tracking of HbA1c between the age of 8 and 12 years. STUDY DESIGN AND METHODS: Anthropometric measurements were taken and HbA1c levels were assessed in 955 children without diabetes aged around 12 years participating in the PIAMA birth cohort study. In 363 of these children HbA1c was also measured at age 8 years. Data on parents and children were collected prospectively by questionnaires. RESULTS: We found no significant association between known risk factors for diabetes and HbA1c at age 12 years. Mean(SD) change in HbA1c between ages 8 and 12 years was 0.6(0.7) mmol/mol per year (or 0.1(0.1) %/yr). Anthropometric measures at age 8 and their change between age 8 and 12 years were not associated with the change in HbA1c. 68.9% of the children remained in the same quintile or had an HbA1c one quintile higher or lower at age 8 years compared to age 12 years. CONCLUSION: The lack of association between known risk factors for diabetes and HbA1c suggest that HbA1c in children without diabetes is relatively unaffected by factors associated with glycaemia. HbA1c at age 8 years is by far the most important predictor of HbA1c at age 12. Therefore, the ranking of HbA1c levels appear to be fairly stable over time.
Huijts PE, etal., Breast Cancer Res. 2007;9(6):R78.
INTRODUCTION: Seven SNPs in five genomic loci were recently found to confer a mildly increased risk of breast cancer. METHODS: We have investigated the correlations between disease characteristics and the patient genotypes of these SNPs in an unselected prospective cohort of 1,267 consecutive patien
ts with primary breast cancer. RESULTS: Heterozygote carriers and minor allele homozygote carriers for SNP rs889312 in the MAP3K1 gene were less likely to be lymph node positive at breast cancer diagnosis (P = 0.044) relative to major allele homozygote carriers. Heterozygote carriers and minor allele homozygote carriers for SNP rs3803662 near the TNCR9 gene were more likely to be diagnosed before the age of 60 years (P = 0.025) relative to major allele homozygote carriers. We also noted a correlation between the number of minor alleles of rs2981582 in FGFR2 and the average number of first-degree and second-degree relatives with breast cancer and/or ovarian cancer (P = 0.05). All other disease characteristics, including tumour size and grade, and oestrogen or progesterone receptor status, were not significantly associated with any of these variants. CONCLUSION: Some recently discovered genomic variants associated with a mildly increased risk of breast cancer are also associated with breast cancer characteristics or family history of breast cancer and ovarian cancer. These findings provide interesting new clues for further research on these low-risk susceptibility alleles.
BACKGROUND: This study aimed to evaluate the prevalence and type of mutations in the major desmosomal genes, Plakophilin-2 (PKP2), Desmoglein-2 (DSG2), and Desmocollin-2 (DSC2), in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) patients. We also aimed to distinguish relevant cli
nical and ECG parameters. METHODS AND RESULTS: Clinical evaluation was performed according to the Task Force Criteria (TFC). We analyzed the genes in (a) 57 patients who fulfilled the ARVD/C TFC (TFC+), (b) 28 patients with probable ARVD/C (1 major and 1 minor, or 3 minor criteria), and (c) 31 patients with 2 minor or 1 major criteria. In the TFC+ ARVD/C group, 23 patients (40%) had PKP2 mutations, 4 (7%) had DSG2 mutations, and 1 patient (2%) carried a mutation in DSC2, whereas 1 patient (2%) had a mutation in both DSG2 and DSC2. Among the DSG2 and DSC2 mutation-positive TFC+ ARVD/C probands, 2 carried compound heterozygous mutations and 1 had digenic mutations. In probable ARVD/C patients and those with 2 minor or 1 major criteria for ARVD/C, mutations were less frequent and they were all heterozygous. Negative T waves in the precordial leads were observed more (P<0.002) among mutation carriers than noncarriers and in particular in PKP2 mutation carriers. CONCLUSIONS: Mutations in DSG2 and DSC2 are together less prevalent (10%) than PKP2 mutations (40%) in Dutch TFC+ ARVD/C patients. Interestingly, biallelic or digenic DSC2 and/or DSG2 mutations are frequently identified in TFC+ ARVD/C patients, suggesting that a single mutation is less likely to cause a full-blown ARVD/C phenotype. Negative T waves on ECG were prevalent among mutation carriers (P<0.002).
Michels M, etal., JACC Cardiovasc Imaging. 2009 Jan;2(1):58-64. doi: 10.1016/j.jcmg.2008.08.003.
OBJECTIVES: To test the hypothesis that carriers of Dutch founder mutations in cardiac myosin-binding protein C (MYBPC3), without left ventricular hypertrophy (LVH) or electrocardiographic abnormalities, have diastolic dysfunction on tissue Doppler imaging (TDI)
, which can be used for the screening of family members in the hypertrophic cardiomyopathy (HCM) population. BACKGROUND: TDI is a more sensitive technique for the assessment of left ventricular contraction and relaxation abnormalities than is conventional echocardiography. METHODS: Echocardiographic studies including TDI were performed in genotyped hypertrophic cardiomyopathy patients (genotype-positive, G+/LVH+; n = 27), mutation carriers without LVH (G+/LVH-; n = 27), and healthy controls (n = 55). The identified mutations in MYBPC3 in the G+/LVH+ subjects were c.2864_2865delCT (12 subjects), c.2373dupG (n = 8), and p. Arg943X (n = 7). In the G+/LVH- subjects, the following mutations were identified: c.2864_2865delCT (n = 11), c.2373dupG (n = 8), and p. Arg943X (n = 8). RESULTS: Mean TDI-derived systolic and early and late diastolic mitral annular velocities were significantly lower in the G+/LVH+ subjects compared with the other groups. However, there was no difference between controls and G+/LVH- subjects. Mean TDI-derived late mitral annular diastolic velocities were significantly higher in the G+/LVH- subjects compared with controls and G+/LVH+ subjects. Using a cut-off value of mean +/- 2 SD, an abnormal late mitral annular diastolic velocity was found in 14 (51%) of G+/LVH- patients. There was no difference among the 3 different mutations. CONCLUSIONS: In contrast to earlier reports, mean mitral annular systolic velocity and early mitral annular diastolic velocity velocities were not reduced in G+/LVH- subjects, and TDI velocities were not sufficiently sensitive for determination of the affected status of an individual subject. Our findings, however, support the theory that diastolic dysfunction is a primary component of pre-clinical HCM.
PURPOSE: We evaluated the effects of dutasteride for preventing or delaying prostate growth and neoplastic changes in a transgenic model of prostate cancer. MATERIALS AND METHODS: Large probasin-large T antigen mice were treated for 4 or 8 weeks with dut
='font-weight:700;'>dutasteride. The prostate and seminal vesicles were compared with those from intact and castrated large probasin-large T antigen mice and WT mice. RESULTS: Dutasteride greatly decreased the transgene induced increase in prostate weight but castration caused greater reduction. Dutasteride inhibited type 1 and 2, 5alpha-reductase activities, decreased DNA and protein, and increased apoptotic bodies and TUNEL staining in the dorsolateral prostate. No evidence of poorly differentiated cancer was seen. Dutasteride did not decrease the weight of the androgen dependent levator ani or bulbocavernosus muscle. CONCLUSIONS: Dutasteride inhibited type 1 and 2, 5alpha-reductase activities, and decreased DNA and protein content of the dorsolateral prostate without affecting androgen responsive muscle weight in large probasin-large T antigen mice. These studies provide support for the hypothesis that a 5alpha-reductase inhibitor inhibits the initiation and/or progression of clinical prostate cancers.
van Gelder CM, etal., J Inherit Metab Dis. 2015 Mar;38(2):305-14. doi: 10.1007/s10545-014-9707-6. Epub 2014 Apr 9.
BACKGROUND: Enzyme-replacement therapy (ERT) in Pompe disease--an inherited metabolic disorder caused by acid alpha-glucosidase deficiency and characterized in infants by generalized muscle weakness and cardiomyopathy--can be complicated by immune responses. Infants that do not produce any endogen
ous acid alpha-glucosidase, so-called CRIM-negative patients, reportedly develop a strong response. We report the clinical outcome of our Dutch infants in relation to their CRIM status and immune response. METHODS: Eleven patients were genotyped and their CRIM status was determined. Antibody formation and clinical outcome were assessed for a minimum of 4 years. RESULTS: ERT was commenced between 0.1 and 8.3 months of age, and patients were treated from 0.3 to 13.7 years. All patients developed antibodies. Those with a high antibody titer (above 1:31,250) had a poor response. The antibody titers varied substantially between patients and did not strictly correlate with the patients' CRIM status. Patients who started ERT beyond 2 months of age tended to develop higher titers than those who started earlier. All three CRIM-negative patients in our study succumbed by the age of 4 years seemingly unrelated to the height of their antibody titer. CONCLUSION: Antibody formation is a common response to ERT in classic infantile Pompe disease and counteracts the effect of treatment. The counteracting effect seems determined by the antibody:enzyme molecular stoichiometry. The immune response may be minimized by early start of ERT and by immune modulation, as proposed by colleagues. The CRIM-negative status itself seems associated with poor outcome.
BACKGROUND: The beta subunit of the high-affinity receptor for IgE (FcepsilonRI-beta) is localized to chromosome 11q13 and has been reported by Cookson et al. to be in close genetic linkage with a gene for atopy. A maternally inherited association was found between the presence of a variant of Fceps
ilonRI-beta, Ile181Leu, and high total serum IgE levels (IgE > 100 IU). In a previous study of 20 Dutch families, we found no evidence for linkage of atopy or bronchial hyperresponsiveness (BHR) to chromosome 11q. OBJECTIVE: Recently segregation analysis in 92 families has given us evidence for two independent major loci accounting for 78% of the observed variance in total serum IgE levels, and linkage analysis using both sib-pair and LOD score methods has identified one major locus for regulation of IgE levels and BHR near the cytokine gene complex on chromosome 5q. The objective of this study is to pursue the identification of the second major locus. METHODS: We have studied markers in the area of the high affinity IgE receptor (FcepsilonRI-beta) on chromosome 11q (D11S1314, FcepsilonRI-beta and D11S987) in 83 families for whom DNA was available. Furthermore, our families have been examined for variance in the FcepsilonRI-beta gene, specifically for Leu181 and Leu181/Leu183 mutations. RESULTS: By sib-pair analysis, there is no evidence for linkage of total serum IgE levels or number of positive skin tests to these markers in our population. Similar negative results were obtained for affected sib-pair analysis of BHR, with the exception of D11S1314, which was significant at P=0.046. The FcepsilonRI-beta gene in 36 female probands, 44 male probands and 46 female spouses was sequenced for these mutations. For each of these 126 individuals sequencing of FcepsilonRI-beta demonstrated a wild-type sequence pattern, with no mutations found in anyone, male or female. CONCLUSION: We are unable to confirm the presence of significant mutations in FcepsilonRI-beta gene in our population, and we cannot confirm that the FcepsilonRI-beta gene is crucial to the pathogenesis of allergic inflammation in asthma.
BACKGROUND: The Brugada syndrome is an inherited cardiac electrical disorder associated with a high incidence of life-threatening arrhythmias. Screening for mutations in the cardiac Na+ channel-encoding gene SCN5A uncovers a mutation in approximately 20% of Brugada syndrome cases. Genetic heterogene
ity and/or undetected SCN5A mutations, such as exon duplications and deletions, could be involved in the remaining 80% mutation-negative patients. OBJECTIVES: Thirty-eight SCN5A mutation-negative Dutch Brugada syndrome probands were studied. The SCN5A gene was investigated for exon duplication and deletion, and a number of candidate genes (Caveolin-3, Irx-3, Irx-4, Irx-5, Irx-6, Plakoglobin, Plakophilin-2, SCN1B, SCN2B, SCN3B, and SCN4B) were tested for the occurrence of point mutations and small insertions/deletions. METHODS: We used a quantitative multiplex approach to determine SCN5A exon copy numbers. Mutation analysis of the candidate genes was performed by direct sequencing of polymerase chain reaction-amplified coding regions. RESULTS: No large genomic rearrangements in SCN5A were identified. No mutations were found in the candidate genes. Twenty novel polymorphisms were identified in these genes. CONCLUSION: Large genomic rearrangements in SCN5A are not a common cause of Brugada syndrome. Similarly, the studied candidate genes are unlikely to be major causal genes of Brugada syndrome. Further studies are required to identify other genes responsible for this syndrome.
Obesity is a rapidly growing threat to public health, driven by the increased occurrence of high caloric diets and sedentary lifestyles. Within this environment, genetic influences may largely determine inter-individual differences in obesity-related traits. To map genes involved in weight regulatio
n, we performed a genome-wide linkage scan for body mass index (BMI), a reliable measure of total body fat, in 192 Dutch families including 315 twins and 210 siblings with data on BMI. Using variance components linkage analysis, regions with LOD-scores greater than 2 were observed on 6p25.1 (LOD-score, 2.13) and 7p21.1 (LOD-score, 2.40). LOD-scores higher than 1 were found on chromosomes 3, 13, 15 and 21. Of note, evidence for the putative quantitative trait locus for BMI on 7p was obtained previously from such diverse populations as Mexican-Americans, Asians and Nigerians, suggesting that the underlying genes may effect weight regulation in diverse environments. An obvious positional candidate in the 7p linkage region is the gene encoding neuropeptide Y (NPY) that controls satiety and food intake.
van der Kallen CJ, etal., Int J Obes Relat Metab Disord 2000 Nov;24(11):1381-91.
OBJECTIVE: To search for novel genes contributing to adiposity in familial combined hyperlipidemia (FCH), a disorder characterized by abdominal obesity, hyperlipidemia and insulin resistance, using a 10cM genome-wide scan. DESIGN: Plasma leptin and soluble tumor necrosis factor receptor superfamily
members 1A and 1B (sTNFRSF1A and sTNFRSF1B, also known as sTNFR1 and sTNFR2) were analyzed as unadjusted and adjusted quantitative phenotypes of adiposity, in addition to body mass index (BMI), in multipoint and single-point analyses. In the second stage of analysis, an important chromosome 1 positional candidate gene, the leptin receptor (LEPR), was studied. SUBJECTS: Eighteen Dutch pedigrees with familial combined hyperlipidemia (FCH) (n= 198) were analyzed to search for chromosomal regions harboring genes contributing to adiposity. RESULTS: Multipoint analysis of the genome scan data identified linkage (log of odds, LOD, 3.4) of leptin levels to a chromosomal region defined by D1S3728 and D1S1665, flanking the leptin receptor (LEPR) gene by approximately 9 and 3 cM, respectively. The LOD score decreased to 1.8 with age- and gender-adjusted leptin levels. Notably, BMI also mapped to this region with an LOD score of 1.2 (adjusted BMI: LOD 0.5). Two polymorphic DNA markers in LEPR and their haplotypes revealed linkage to unadjusted and adjusted BMI and leptin, and an association with leptin levels was found as well. In addition, the marker D8S1110 showed linkage (LOD 2.8) with unadjusted plasma concentrations of soluble TNFRSF1A. BMI gave a LOD score of 0.6. Moreover, a chromosome 10 q-ter locus, AFM198ZB, showed linkage with adjusted BMI (LOD 3.3). CONCLUSION: These data provide evidence that a human chromosome 1 locus, harboring the LEPR gene, contributes to plasma leptin concentrations, adiposity and body weight in humans affected with this insulin resistant dyslipidemic syndrome. Novel loci on chromosome 8 and 10 qter need further study.
Genes contributing to common forms of hypertension are largely unknown. A number of studies in humans and in animal models have revealed associations between insulin resistance, dyslipidemia, and elevated hypertension. To identify genes contributing to blood pressure (BP) variation associated with i
nsulin-resistant dyslipidemia, we conducted a genome-wide scan for BP in a set of 18 Dutch families exhibiting the common lipid disorder familial combined hyperlipidemia. Our results reveal a locus on chromosome 4 that exhibits a significant lod score of 3.9 with systolic BP. In addition, this locus also appears to influence plasma free fatty acid levels (lod=2.4). After adjustment for age and gender, the lod score for systolic BP increased to 4.6, whereas the lod score for free fatty acid levels did not change. The chromosome 4 locus contains an attractive candidate gene, alpha-adducin, which has been associated with altered BP in animal studies and in some human populations. However, we found no evidence for an association between 2 intragenic alpha-adducin polymorphisms and systolic BP in this sample. We also observed suggestive evidence for linkage (lod=1.8) of diastolic BP to the lipoprotein lipase gene locus on chromosome 8p, supporting a finding previously observed in a separate insulin-resistant population. In addition, we also obtained suggestive evidence for linkage of systolic BP (lod=2.4) and plasma apolipoprotein B levels (lod=2.0) to a locus on proximal chromosome 19p. In conclusion, our genome scan results support the existence of multiple genetic factors that can influence both BP and plasma lipid parameters.
Breast cancer accounts for over 20% of all female cancers. A positive family history remains one of the most important risk factors for the disease, with first-degree relatives of patients having a twofold elevated risk. Known breast cancer susceptibility genes such as BRCA1 and BRCA2 explain only 2
0-25% of this risk, suggesting the existence of other breast cancer susceptibility genes. Here, we report the results of a genome-wide linkage scan in 55 high-risk Dutch breast cancer families with no mutations in BRCA1 and BRCA2. Twenty-two of these families were also part of a previous linkage study by the Breast Cancer Linkage Consortium. In addition, we performed CGH analyses in 61 tumors of these families and 31 sporadic tumors. Three regions were identified with parametric HLOD scores >1, and three with nonparametric LOD scores >1.5. Upon further marker genotyping for the candidate loci, and the addition of another 30 families to the analysis, only the locus on chromosome 9 (9q21-22, marker D9S167) remained significant, with a nonparametric multipoint LOD score of 3.96 (parametric HLOD 0.56, alpha = 0.18). With CGH analyses we observed preferential copy number loss at BAC RP11-276H19, containing D9S167 in familial tumors as compared to sporadic tumors (P < 0.001). Five candidate genes were selected from the region around D9S167 and their coding regions subjected to direct sequence analysis in 16 probands. No clear pathogenic mutations were found in any of these genes.
van Tilburg JH, etal., Eur J Clin Invest 2003 Dec;33(12):1070-4.
A genome scan was performed in obese type 2 diabetes mellitus pedigrees to identify susceptibility loci involved in obesity-driven type 2 diabetes mellitus. We studied the 20% most obese diabetes pedigrees from a confined Dutch population from around the town of
Breda. Previously we, and others, have already shown that a susceptibility locus influencing obesity in diabetes may reside on chromosome 18p11. We now report evidence to also suggest linkage for type 2 diabetes in these obese pedigrees on chromosome regions 11p (genome-wide P-value = 0.061) and 12q (genome-wide P-value = 0.029), thereby confirming previous findings from corresponding regions. The linkage found in the Breda Cohort of type 2 diabetes patients is influenced by obesity. This supports the notion that a genetic predisposition to obesity is probably intertwined with a genetic predisposition to type 2 diabetes. Further efforts should address the question of how, on a genetic level, these two factors interact.
van Waveren Hogervorst GD, etal., Eur J Haematol. 1987 May;38(5):405-9.
Size distribution curves of red blood cells were used to detect the presence of microcytes in peripheral blood of members of a Dutch family with hereditary sideroblastic anaemia. 22 of 49 members of this family have a bimodal erythrocyte volume distribution curv
e and a dimorphic blood picture. The pattern of inheritance of this morphological abnormality is clearly autosomal. It is suggested that the study of red blood cell size distribution curves may add valuable information on the pattern of inheritance in other families with hereditary sideroblastic anaemia.
Acute intermittent porphyria (AIP) is an autosomal dominant disease characterized by a deficiency of porphobilinogen deaminase (PBGD). Up to now 14 different mutations have been described. In an effort to investigate the molecular epidemiology of AIP we have undertaken a systematic study of differen
t exons of the PBGD gene from a large number of unrelated patients. Here, exon 8 from 82 unrelated Dutch and French AIP patients was examined using single strand confirmation polymorphism analysis (SSCP) after polymerase chain reaction (PCR) amplification. A single base mutation, C to T, at position 346 of the sequence coding for PBGD was observed in 15 Dutch families but in only 1 French family. A simple PCR assay is described to facilitate the diagnosis of this common mutation at the DNA level.
PURPOSE: To determine the genetic defects underlying autosomal recessive retinitis pigmentosa (arRP) in the Dutch population and in a subset of patients originating from other countries. The hypothesis was that, because there has been little migration over the p
ast centuries in certain areas of The Netherlands, a significant fraction of Dutch arRP patients carry their genetic defect in the homozygous state. METHODS: High-resolution genome-wide SNP genotyping on SNP arrays and subsequent homozygosity mapping were performed in a large cohort of 186 mainly nonconsanguineous arRP families living in The Netherlands. Candidate genes residing in homozygous regions were sequenced. RESULTS: In ~94% of the affected individuals, large homozygous sequences were identified in their genome. In 42 probands, at least one of these homozygous regions contained one of the 26 known arRP genes. Sequence analysis of the corresponding genes in each of these patients revealed 21 mutations and two possible pathogenic changes, 14 of which were novel. All mutations were identified in only a single family, illustrating the genetic diversity within the Dutch population. CONCLUSIONS: This report demonstrates that homozygosity mapping is a powerful tool for identifying the genetic defect underlying genetically heterogeneous recessive disorders like RP, even in populations with little consanguinity.
Howard TD, etal., Am J Respir Cell Mol Biol. 2001 Sep;25(3):377-84.
Asthma and atopy are related conditions that may share similar genetic susceptibility. Linkage studies have identified a region on chromosome 5q that contains biologic candidates for both asthma and atopy phenotypes, including several proinflammatory cytokines. Interleukin (IL)-13, one of the candid
ate genes in the region, is directly involved in the regulation of immunoglobulin E and has been associated with both asthma and atopy. We sought to identify new polymorphisms in the IL-13 gene, and evaluated the involvement of a subset of these variants in asthma and atopy in a case-control study using probands and spouses from a Dutch asthma family study. IL-13 was sequenced in 20 probands and 20 unaffected spouses, and 10 polymorphisms were identified, four novel and six previously reported. Three single nucleotide (nt) polymorphisms (SNPs) were detected in the 5'-promoter region, two in intron 1, and five in exon 4. Only one of the exon 4 SNPs resulted in an amino-acid change (Arg130Gln). We analyzed three SNPs in IL-13 in an extended group of 184 probands and their spouses: one in the promoter region (-1111), the Arg130Gln (nt position 4257), and a 3' untranslated region SNP (nt position 4738). The most significant associations were observed to asthma (P = 0.005), bronchial hyperresponsiveness (P = 0.003), and skin-test responsiveness (P = 0.03) with the -1111 promoter. These results provide evidence that variation in the IL-13 gene is involved in the pathogenesis of asthma and atopy. Further investigation is required to determine which specific alleles or combination of alleles contribute to these phenotypes, and the possible downstream effects of the resulting change in IL-13 levels or activity.
In 517 Dutch families at a family cancer clinic, we screened for BRCA1/2 alterations using the Protein Truncation Test (PTT) covering approximately 60% of the coding sequences of both genes and direct testing for a number of previously identified Dut
ont-weight:700;'>Dutch recurrent mutations. In 119 (23%) of the 517 families, we detected a mutation in BRCA1 (n=98; 19%) or BRCA2 (n=21; 4%). BRCA1/2 mutations were found in 72 (52%) of 138 families with breast and ovarian cancer (HBOC), in 43 (13%) of the 339 families with breast cancer only (HBC), in 4 (36%) of 11 families with ovarian cancer only (HOC), and in nine of 29 families with one single young case (<40 years) of breast cancer. Between the different subgroups of families (subdivided by the number of patients, cancer phenotype and age of onset) the proportion of BRCA1/2 mutations detected, varied between 6 and 82%. Eight different mutations, each encountered in at least six distinct families, represented as much as 61% (73/119 families) of all mutations found. The original birthplaces of the ancestors of carriers of these eight recurrent mutations were traced. To estimate the relative contribution of two important regional recurrent mutations (BRCA1 founder mutation IVS12-1643del3835 and BRCA2 founder mutation 5579insA) to the overall occurrence of breast cancer, we performed a population-based study in two specific small regions. The two region-specific BRCA1 and BRCA2 founder mutations were detected in 2.8% (3/106) and 3.2% (3/93) of the unselected breast tumours, respectively. Of tumours diagnosed before the age of 50 years, 6.9% (3/43) and 6.6% (2/30) carried the region-specific founder mutation. Thus, large regional differences exist in the prevalence of certain specific BRCA1/BRCA2 founder mutations, even in very small areas concerning populations of approximately 200000 inhabitants.
Axenovich T, etal., J Med Genet. 2011 Dec;48(12):802-9. doi: 10.1136/jmedgenet-2011-100436. Epub 2011 Nov 5.
BACKGROUND: Despite extensive research on the genetic determinants of glaucoma, the genes identified to date explain only a small proportion of cases in the general population. METHODS: Genome-wide linkage and association analyses of quantitative traits related to glaucoma were
performed: intraocular pressure, size and morphology of the optic disc (individual and combined by method of principal components) and thickness of the retinal nerve fibre layer (RNFL), in a large pedigree from a genetically isolated Dutch population. RESULTS: For the size of the optic disc, the study demonstrated a significant linkage signal (logarithm of odds (LOD)=3.6) at the LRP1B region on chromosome 2q21.2-q22.2 and significant association (p=8.95×10(-12)) with the previously reported CDC7/TGFBR3 locus at 1p22. For parameters describing morphology of the optic disc, the study obtained significant linkage signal (LOD=4.6) at regions SIRPA and RNF24/PANK2 at 20p13 (false discovery rate (FDR) based q value <0.05) and genome-wide significant association (p=2.38×10(-9)) with a common variant in the RERE gene at 1p36. Suggestive linkage and association signals indicated loci for morphology of the optic disc at 2q31-q33 (IGFBP2 locus) and for RNFL thickness at 3p22.2 (DCLK3 locus) and 14q22-q23 (SIX1 locus). CONCLUSION: This study identified new linkage regions at 20p13 (SIRPA and RNF24/PANK2 loci) and 2q33-q34 (IGFBP2 locus) for parameters describing morphology of the optic disc. The results of the study also suggested common genetic control of these parameters and RNFL thickness by SIX1 and doublecotin family genes. Finally, association signals for the recently reported RERE and LRP1B loci and the well known CDC7, TGFBR3, and ATOH7 loci were replicated.
van Dijk M, etal., Nat Genet. 2005 May;37(5):514-9. Epub 2005 Apr 3.
Preeclampsia is a pregnancy-associated disease with maternal symptoms but placental origin. Epigenetic inheritance is involved in some populations. By sequence analysis of 17 genes in the 10q22 region with maternal effects, we narrowed the minimal critical region linked with preeclampsia in the Neth
erlands to 444 kb. All but one gene in this region, which lies within a female-specific recombination hotspot, encode DNA- or RNA-binding proteins. One gene, STOX1 (also called C10orf24), contained five different missense mutations, identical between affected sisters, cosegregating with the preeclamptic phenotype and following matrilineal inheritance. Four STOX1 transcripts are expressed in early placenta, including invasive extravillus trophoblast, generating three different isoforms. All contain a winged helix domain related to the forkhead (FOX) family. The largest STOX1 isoform has exclusive nuclear or cytoplasmic expression, indicating activation and inactivation, respectively, of the PI3K-Akt-FOX pathway. Because all 38 FOX proteins and all 8 STOX1 homologs have either tyrosine or phenylalanine at position 153, the predominant Y153H variation is highly mutagenic by conservation criteria but subject to incomplete penetrance. STOX1 is a candidate for preeclampsia controlling polyploidization of extravillus trophoblast.
van der Luijt RB, etal., Hum Mutat. 1997;9(1):7-16.
Germline mutations of the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominant predisposition to colorectal cancer. We screened the entire coding region of the APC gene for mutations in an unselected series of 105 Dut
ght:700;'>Dutch FAP kindreds. For the analysis of exons 1-14, we employed the GC-clamped denaturing gradient gel electrophoresis (DGGE), while the large exon 15 was examined using the protein truncation test. Using this approach, we identified 65 pathogenic mutations in the above 105 apparently unrelated FAP families. The mutations were predominantly either frameshifts (39/65) or single base substitutions (18/65), resulting in premature stop codons. Mutations that would predict abnormal RNA splicing were identified in seven cases. In one of the families, a nonconservative amino acid change was found to segregate with the disease. In spite of the large number of APC mutations reported to date, we identified 27 novel germline mutations in our patients, which reiterates the great heterogeneity of the mutation spectrum in FAP. In addition to the point mutations identified in our patients, structural rearrangements of APC were found in two pedigrees, by Southern blot analysis. The present study indicates that the combined use of DGGE, protein truncation test, and Southern blot analysis offers an efficient strategy for the presymptomatic diagnosis of FAP by direct mutation detection. We found that the combined use of the currently available molecular approaches still fails to identify the underlying genetic defect in a significant subset of the FAP families. The possible causes for this limitation are discussed.
Nielsen M, etal., J Med Genet. 2005 Sep;42(9):e54.
OBJECTIVE: To investigate the contribution of MYH associated polyposis coli (MAP) among polyposis families in the Netherlands, and the prevalence of colonic and extracolonic manifestations in MAP patients. METHODS: 170 patients with polyposis coli, who previously tested negative for APC mutations, w
ere screened by denaturing gradient gel electrophoresis and direct sequencing to identify MYH germline mutations. RESULTS: Homozygous and compound heterozygous MYH mutations were identified in 40 patients (24%). No difference was found in the percentage of biallelic mutation carriers between patients with 10-99 polyps or 100-1000 polyps (29% in both groups). Colorectal cancer was found in 26 of the 40 patients with MAP (65%) within the age range 21 to 67 years (median 45). Complete endoscopic reports were available for 16 MAP patients and revealed five cases with gastro-duodenal polyps (31%), one of whom also presented with a duodenal carcinoma. Breast cancer occurred in 18% of female MAP patients, significantly more than expected from national statistics (standardised morbidity ratio = 3.75). CONCLUSIONS: Polyp numbers in MAP patients were equally associated with the attenuated and classical polyposis coli phenotypes. Two thirds of the MAP patients had colorectal cancer, 95% of whom were older than 35 years, and one third of a subset of patients had upper gastrointestinal lesions. Endoscopic screening of the whole intestine should be carried out every two years for all MAP patients, starting from age 25-30 years. The frequent occurrence of additional extraintestinal manifestations, such as breast cancer among female MAP patients, should be thoroughly investigated.
Hereditary C-cell carcinoma is encountered in multiple endocrine neoplasia type 2A (MEN 2A), MEN 2B, and familial medullary thyroid carcinoma (FMTC). Mutations of the RET proto-oncogene are associated with all three diseases. To obtain an insight into the molecular heterogeneity of MEN 2 syndromes a
nd FMTC in the Netherlands, probands of 20 MEN 2A families, two FMTC families, and seven MEN 2B families were analyzed by the polymerase chain reaction (PCR), DNA sequencing, and restriction enzyme digestion for abnormalities in the RET proto-oncogene. RET mutations were found in all cases. All MEN 2A families had a mutation involving one of five cysteine codons in exons 10 and 11 of RET. Two novel dinucleotide mutations and a de novo mutation were found. Both FMTC families had a mutation of the Cys at codon 618. All MEN 2B probands carried a Met to Thr mutation in exon 16. All mutations could be confirmed by restriction enzyme digestion of PCR amplicons. Identification of the RET mutation in the Dutch population with hereditary C-cell carcinoma facilitates genetic testing for families or individuals at risk for MEN 2A, FMTC, and MEN 2B.
DNA samples from 100 unrelated Belgian patients with familial hypercholesterolemia (FH) were screened for the presence of specific low-density lipoprotein receptor (LDLR) gene mutations, previously shown to be prevalent in related populations. Two point mutations, viz., P664L and a G to A splicing
defect at position 1359-1, were detected in single Flemish-speaking families. A long-distance polymerase chain reaction (PCR) assay, used to screen for the 4-kb and 2.5-kb deletions previously identified by Southern blot analyses in different parts of The Netherlands, revealed a 3-kb deletion in two Belgian patients. Comparison of PCR product length showed that both Dutch deletions of exons 7-8 are identical to that found in Belgians, but different from the 2.5-kb deletion previously described in South Africans of mixed ancestry. The Belgian patients probably share a common ancestor, for each mutation identified, with FH patients from The Netherlands, since all three mutations were associated with the same LDLR gene haplotype as described for the Dutch population. Analysis of the deletion junctions demonstrated the role of a 31-bp repetitive sequence in the generation of large rearrangements involving exons 7 and 8 of the LDLR gene. The finding that only 4 out of 100 analyzed Belgian hypercholesterolemics carry a known LDLR mutation that is prevalent in related populations suggests that the Belgian FH population has its own spectrum of mutations.
Schrauwen I, etal., Otol Neurotol. 2009 Dec;30(8):1079-83. doi: 10.1097/MAO.0b013e3181ab3058.
HYPOTHESIS/BACKGROUND: Otosclerosis is a frequent cause of hearing impairment in the Caucasian population and is characterized by abnormal bone remodeling of the otic capsule. Associations with several genes have been reported, and recently, an association between the renin-angiotensin-aldosterone
system and otosclerosis has been suggested. Polymorphisms in 3 genes were investigated: angiotensinogen (AGT), angiotensin I-converting enzyme (ACE), and angiotensin II receptor, type 1. The polymorphisms in AGT and ACE were associated with disease, and both were reported to interact with each other. In the current study, a replication study was done in a large Belgian-Dutch population to investigate whether this association could be replicated. METHODS: The same 3 polymorphisms in AGT, ACE, and angiotensin II receptor, type 1 as analyzed in the original study were investigated in 692 otosclerosis patients and 692 controls of Belgian-Dutch origin. RESULTS: None of the polymorphisms were significantly associated with disease. Interaction between AGT and ACE polymorphisms was not significant either. CONCLUSION: We could not confirm the association between AGT and ACE, nor could we find evidence for interaction between both genes in otosclerosis. Because the current patient set is much larger than the one from the original study, this study holds sufficient power to detect the previously reported associations. Nonreplication in this case probably indicates that the initial results were false positive, although a role for these genes in otosclerosis cannot be definitively ruled out.
van der Hoeven SM, etal., Nephrol Dial Transplant. 2012 Oct;27(10):3855-62. doi: 10.1093/ndt/gfs320. Epub 2012 Jul 27.
BACKGROUND: Primary hyperoxaluria Type 1, an inherited disorder with increased endogenous oxalate production, leads to the development of urolithiasis, nephrocalcinosis and end-stage renal disease (ESRD). Contrary to the general belief that patients diagnosed during adulthood experience a relatively
mild course of disease, we were confronted with several cases of ESRD caused by previously undiagnosed primary hyperoxaluria. METHODS: To study renal and patient survival in relation with genotype, age at onset of disease and therapeutic delay, we performed a nationwide search among all Dutch nephrologists and paediatric nephrologists. RESULTS: Of the 79 included patients, 38% was diagnosed at an adult age. ESRD was present at the time of diagnosis in 26% of paediatric diagnosed patients versus 52% of adult-diagnosed patients (P = 0.021). Homozygosity for the pyridoxine-responsive p.Gly170Arg or p.Phe152Ile genotype was found in 26% of paediatric diagnosed patients versus 68% of adult-diagnosed patients (P < 0.001). Of homozygous p.Gly170Arg or p.Phe152Ile patients, 48% developed ESRD at a median age of 37 years, compared with 48% in those with other mutations at a median age of 0.5 years (P < 0.001). Of the 16 patients found through family screening, 81% had a preserved renal function. CONCLUSIONS: The high prevalence of pyridoxine-responsive genotypes and favourably prognosis of timely treatment warrant early diagnostic screening for primary hyperoxaluria Type 1 in patients with recurrent urolithiasis. This will preserve kidney function and prevent diagnosis of adult diagnosed patients in ESRD.
de Heer AM, etal., Audiol Neurootol. 2011;16(2):93-105. doi: 10.1159/000313282. Epub 2010 Jun 26.
In a Dutch family with autosomal recessive hearing loss, genome-wide single-nucleotide polymorphism analysis mapped the genetic defect to the DFNB7/11 locus. A novel homozygous A-to-G change in the TMC1 gene was detected near the splice donor site of intron 19 (
c.1763+3A-->G) segregating with the hearing loss in this family. One of the 6 transmembrane domains and the actual TMC channel domain are predicted to be absent in the mutant protein. The sensorineural hearing impairment in this DFNB7/11 family has a postlingual onset. Audiometric analysis initially showed a steeply downward-sloping threshold configuration. The progressive phenotype in this family resembles the phenotype previously described for families with dominant TMC1 mutations (DFNA36) rather than that of families with recessive TMC1 mutations (DFNB7/11) which invariably cause severe-to-profound prelingual hearing impairment.
Top B, etal., Atherosclerosis. 1990 Aug;83(2-3):127-36.
DNA samples from 53 unrelated Dutch patients with familial hypercholesterolemia (FH) were screened for rearrangements in the gene for the LDL receptor (LDLR) by Southern analysis. Four different mutations have been detected by hybridisation of BglII digested ge
nomic DNA with an exon 10-14 containing cDNA probe. The mutations are defined by a 7 kb insertion near exon 11, a partial gene duplication encompassing exons 9-12, a 4 kb deletion of exons 7 and 8 and an 0.4 kb deletion comprising the 5'-part of exon 16. These four different rearrangements in the LDLR gene account for 17% of the mutations in the Dutch FH population sample. Interestingly, the 4 kb deletion was detected in 5 unrelated FH patients (9.5%) and appeared to be identical to the deletion previously described (Russell, D.W. et al., Arteriosclerosis, 9 (Suppl. I) (1989) I-8; Russell, D.W. et al., Cold Spring Harbor Symp. Quant. Biol., 51 (1987) 401). in an FH patient of Dutch origin. This suggests that the 4 kb deletion is a common mutation in the Dutch FH population.
van Moorsel CH, etal., Am J Respir Crit Care Med. 2010 Jul 23.
RATIONALE: Familial clustering of adult Idiopathic Interstitial Pneumoniaas (IIP) suggests that genetic factors might play an important role in disease development. Mutations in surfactant protein C (SFTPC) have been found in children and families suffering from idiopathic pneumonias, while co-carri
age of a mutation in ATP-binding cassette sub-family A member 3 (ABCA3) was postulated to have a disease modifying effect. OBJECTIVES: To investigate the contribution of SFTPC mutations to adult Familial Pulmonary Fibrosis (FPF) and the disease modifying effect of mutations in ABCA3 within their families. METHODS: Twenty-two unrelated FPF patients (10%) were identified within our single-center cohort of 229 patients with IIP. SFTPC was sequenced in 20 FPF and 20 sporadic patients. In patients with an SFTPC mutation, sequencing of ABCA3 was performed. Discovered variants were typed in >100 controls and 121 additional sporadic IIP patients. MEASUREMENTS AND MAIN RESULTS: In 5/20 unrelated FPF patients (25%, CI 10-49) a mutation in SFTPC was detected: M71V, IVS4+2, and three times I73T. No mutations were detected in the sporadic or control cohort. Patients with SFTPC mutations presented with a histopathological pattern of UIP and nodular septa thickening and multiple lung cysts in combination with ground glass or diffuse lung involvement on chest HRCT. Two variants in ABCA3 were found in adult FPF patients but not in affected children. CONCLUSION: Mutations in SFTPC are a frequent cause of adult FPF in our cohort. Nonclassifiable radiological patterns with cystic changes, and histopathological patterns of UIP are characteristics of adult SFTPC mutation carriers.
Nicastrin regulates gamma-secretase cleavage of the amyloid precursor protein by forming complexes with presenilins, in which most mutations causing familial early-onset Alzheimer disease (EOAD) have been found. The gene encoding nicastrin (NCSTN) maps to 1q23, a region that has been linked and asso
ciated with late-onset Alzheimer disease (LOAD) in various genome screens. In 78 familial EOAD cases, we found 14 NCSTN single-nucleotide polymorphisms (SNPs): 10 intronic SNPs, 3 silent mutations, and 1 missense mutation (N417Y). N417Y is unlikely to be pathogenic, since it did not alter amyloid beta secretion in an in vitro assay and its frequency was similar in case and control subjects. However, SNP haplotype estimation in two population-based series of Dutch patients with EOAD (n=116) and LOAD (n=240) indicated that the frequency of one SNP haplotype (HapB) was higher in the group with familial EOAD (7%), compared with the LOAD group (3%) and control group (3%). In patients with familial EOAD without the APOE epsilon4 allele, the HapB frequency further increased, to 14%, resulting in a fourfold increased risk (odds ratio = 4.1; 95% confidence interval 1.2-13.3; P=.01). These results are compatible with an important role of gamma-secretase dysfunction in the etiology of familial EOAD.
Chlamydia trachomatis infections demonstrate remarkable differences in clinical course that are approximately 40% based on host genetic variation. Here, we study the single nucleotide polymorphisms (SNPs) and their haplotypes in TLR2, TLR4 and TLR9 (TLR2 +2477G>A; TLR2 -16934T>A; TLR4+896A>G; TLR9 -
1237T>C and TLR9 +2848G>A) in relation to the susceptibility to, and severity of C. trachomatis infections. We analysed the five SNPs in a cohort of 770 Dutch Caucasian women either attending a sexually transmitted diseases outpatient clinic (n = 731) or having complaints of subfertility (n = 39). Haplotype analyses showed a trend for TLR2 haplotype I (-16934T/+2477G) to protect against the development of symptoms and tubal pathology (Ptrend = 0.03) after Chlamydia infection. In the susceptibility cohort, TLR9 haplotype III (-1237C/+2848A) showed a significant decreasing trend in the development of symptoms after C. trachomatis infection (P = 0.02, OR: 0.55, 95%CI: 0.33-0.91). Logistic regression of the TLR2 haplotypes, TLR4+896A>G, and TLR9 haplotypes showed that the TLR2 haplotype combinations AG-TA and AG-TG confer risk (OR 3.4 (P = 0.01) and 1.6 (P = 0.03)), while the TLR9 haplotype combination TG-TA protects against C. trachomatis infections (OR: 0.4, P = 0.004). Our study shows that both TLR2 and TLR9 genes and SNP combinations do influence the clinical course of Chlamydia infections.
The aim of the study was to investigate the associations between UGT1A1(*)28 genotype and (1) response rates, (2) febrile neutropenia and (3) dose intensity in patients with metastatic colorectal cancer treated with irinotecan. UGT1A1(*)28 genotype was determined in 218 patients receiving irinotecan
(either first-line therapy with capecitabine or second-line as monotherapy) for metastatic colorectal cancer. TA(7) homozygotes receiving irinotecan combination therapy had a higher incidence of febrile neutropenia (18.2%) compared to the other genotypes (TA(6)/TA(6) : 1.5%; TA(6)/TA(7) : 6.5%, P=0.031). TA(7) heterozygotes receiving irinotecan monotherapy also suffered more febrile neutropenia (19.4%) compared to TA(6)/TA(6) genotype (2.2%; P=0.015). Response rates among genotypes were not different for both regimens: combination regimen, P=0.537; single-agent, P=0.595. TA(7) homozygotes did not receive a lower median irinotecan dose, number of cycles (P-values >or=0.25) or more frequent dose reductions compared to the other genotypes (P-values for trend; combination therapy: 0.62 and single-agent: 0.45). Reductions were mainly (>80%) owing to grade >or=3 diarrhoea, not (febrile) neutropenia. TA(7)/TA(7) patients have a higher incidence of febrile neutropenia upon irinotecan treatment, but were able to receive similar dose and number of cycles compared to other genotypes. Response rates were not significantly different.
Type 2 diabetes shares substantial genetic and phenotypic overlap with familial combined hyperlipidemia. Upstream stimulatory factor 1 (USF1), a well-established susceptibility gene for familial combined hyperlipidemia, is postulated to be such a shared genetic determinant. We evaluated two establis
hed variants in familial combined hyperlipidemia (rs2073658 and rs3737787) for association with type 2 diabetes in two Dutch case-control samples (N=2011). The first case-control sample comprised 501 subjects with type 2 diabetes from the Breda cohort and 920 healthy blood bank donors of Dutch Caucasian origin. The second case-control sample included 211 subjects with type 2 diabetes, and 379 normoglycemic controls. SNP rs2073658 and SNP rs3737787 were in perfect linkage disequilibrium. In the first case-control sample, prevalence of the major allele was higher in patients than in controls (75% versus 71%, OR=1.25, p=0.018). A similar effect-size and -direction was observed in the second case-control sample (76% versus 72%, OR=1.22, p=0.16). A combined analysis strengthened the evidence for association (OR=1.23, p=0.006). Notably, the increased risk for type 2 diabetes could be ascribed to the major allele, and its high frequency translated to a substantial population attributable risk of 14.5%. In conclusion, the major allele of rs2073658 in the USF1 gene is associated with a modestly increased risk to develop type 2 diabetes in Dutch Caucasians, with considerable impact at the population level.