Caulfield MJ and Stanko D, J Immunol. 1992 Apr 1;148(7):2068-73.
With age, NZB mice develop anti-RBC autoantibodies resulting in the development of autoimmune hemolytic anemia. We now have evidence that this spontaneous autoantibody response consists of antibodies that are similar in specificity and Id expression to a pathogenic autoantibody (G8
eight:700;'>G8) that was cloned from an autoimmune NZB mouse. Similar to autoantibodies eluted from Coombs'-positive mouse E (MRBC), the G8 mAb recognizes native (unmodified) MRBC but not RBC from other species. Interestingly, G8 and four additional mAb bind with a higher titer to bromelain-treated MRBC than to native MRBC. Nucleotide sequence analysis reveals, however, that unlike "natural" antibodies that react solely with bromelain-MRBC, G8 is encoded by a J558 VH gene and a V kappa 12,13 L-chain gene. Thus G8 is clearly distinct from antibodies to bromelain-MRBC which are encoded by unrelated V genes. Instead, the sequence of the G8 VH chain was found to be nearly identical to that of an anti-DNA mAb derived from an MRL-lpr/lpr mouse. The results suggest Coombs'-positive autoantibodies from NZB mice are not derived from "natural" antibodies, but rather, consist of a restricted set of autoantibodies expressing the G8 IdX.
OBJECTIVE: We examined the influence of genetic variation of the ATP-binding cassette (ABC) transporter G8 on apolipoprotein B (apoB) kinetics in overweight/obese men. METHODS AND RESULTS: Very low-density lipoprotein (VLDL)
and low-density lipoprotein (LDL) apoB kinetics were determined in 47 men (body mass index 32+/-3 kg/m2) using stable isotope and multicompartmental modeling to estimate production rate (PR), fractional catabolic rate (FCR), and VLDL to LDL-apoB conversion. Relative to the wild-type (400TT), subjects carrying the ABCG8 400K allele had significantly decreased plasma concentrations of triglycerides, sitosterol, and campesterol, lower PR of VLDL-apoB, and higher VLDL to LDL-apoB conversion (P<0.05). The PR and FCR of LDL-apoB were also significantly higher with 400K allele (P<0.05). No association was found with ABCG8 D19H. Compared with APOE2 or APOE3, APOE4 carriers had significantly higher plasma LDL-cholesterol concentrations and lower LDL-apoB FCR. During multiple regression analysis including age, homeostasis model assessment score, plasma concentrations of sitosterol, and lathosterol, ABCG8 and apoE genotypes were independent determinants of VLDL-apoB PR and LDL-apoB FCR, respectively (P<0.05). CONCLUSIONS: Variation in the ABC transporter G8 appears to independently influence the metabolism of apoB-containing lipoproteins in overweight/obese subjects. This may have therapeutic implications for the management of dyslipidemia in these subjects.
The ratio of serum plant sterols to cholesterol is positively correlated with the fractional cholesterol absorption, whereas serum precursors of cholesterol synthesis are positively correlated with cholesterol synthesis. Recently, two ABC (ATP-binding cassette) transporters, ABCG5 and ABCG8
='font-weight:700;'>G8, have been described as playing an important role in the absorption and excretion of sterols. In the present study, we tested the hypothesis that genetic variation in ABCG5/ABCG8 influences the levels of serum plant sterol (sitosterol) and cholesterol precursor (lathosterol) in Japanese primary hypercholesterolaemic patients (n = 100). We identified a novel mutation [859T/C (C287R)] and a novel polymorphism [1285A/G (M429V)] at the ABCG5/ABCG8 loci, as well as four polymorphisms reported previously [1810C/G (Q604E), 161G/A (C54Y), 1199C/A (T400K) and 1895C/T (A632V)]. In carriers of the novel M429V variant, the serum level of sitosterol and the sitosterol/cholesterol ratio were significantly higher than those in non-carriers (3.64 compared with 2.56 microg/ml, and 1.45 microg/mg compared with 1.00 microg/mg respectively; P < 0.01 for both), and serum lathosterol tended to be lower (1.95 microg/ml compared with 3.03 microg/ml; P = 0.08), whereas no significant difference was observed in other lipid profiles. These four polymorphisms (1810C/G, 161G/A, 1199C/A and 1285A/G) generated six haplotypes, and the C/G/C/G haplotype was significantly associated with a higher sitosterol level and sitosterol/cholesterol ratio compared with the other five haplotypes (P < 0.05 for both). We conclude that, in 8% of patients with hypercholesterolaemia, the novel ABCG8 M429V variant was associated with higher cholesterol absorption efficiency. Future studies should investigate whether these findings have implications for the optimal cholesterol-lowering drug treatment in hypercholesterolaemic patients.
BACKGROUND: The long-term excessive intake of exogenous cholesterol can lead to abnormally elevated blood lipid levels and induce cardiovascular and cerebrovascular diseases. However, the influence and relevance of exogenous cholesterol on plasma cholesterol components were still unclear,
and the influence on intestinal lipid metabolism targets needs to be further explored. METHODS: In vivo, the C57BL/6 + NF group and ApoE-/- + NF group mice were fed a normal specific pathogen-free (SPF) diet; the ApoE-/- + HF group mice were fed a high-cholesterol SPF diet. The plasma and jejunum tissue homogenate were obtained for non-targeted lipid metabolomics. The lipid droplets in tissues were observed by transmission electron microscope and oil red O staining. Jejunum tissue morphology was observed by HE staining. The kits were used to detect lipid content in plasma, tissues, intestinal contents, and cells. Western blot, RT-PCR, immunohistochemistry (IHC), and immunofluorescence (IF) were used to observe the key target of lipid metabolism. In vitro, the final concentration of cholesterol was 100 μmol/L in Caco-cells. Oil red O staining, western blot, RT-PCR and immunofluorescence (IF) were used to observe the changes of lipid metabolism. Finally, the influence of liver X receptor alpha (LXRα) on intestinal cholesterol metabolism was clarified by applying the LXRα inhibitor GSK2033 and siRNA targeting LXRα. RESULTS: The aortic arch and intestinal villi of the two groups of ApoE-/- mice showed apparent lesions and lipid accumulation, and there were significant changes in a variety of lipids in the plasma and jejunum. Additionally, jejunum LXRα was markedly activated. High cholesterol can significantly activate LXRα in Caco-2 cells. After LXRα was inhibited, the protein level of ATP-binding cassette transporter A1/G5/G8 (ABCA1/G5/G8) decreased, and the quantity and volume of intracellular lipids soared. CONCLUSION: In a high-cholesterol environment, the intestine promotes the excretion of cholesterol from the cell through the LXRα-ABCA1/G5/G8 pathway, reduces the intestinal intake of a variety of exogenous cholesterol, and reduces the risk of AS.
Dikkers A, etal., Atherosclerosis. 2015 Dec;243(2):402-6. doi: 10.1016/j.atherosclerosis.2015.10.010. Epub 2015 Oct 8.
BACKGROUND AND AIMS: Biliary cholesterol secretion is important for reverse cholesterol transport (RCT). ABCG5/G8 contribute most cholesterol mass secretion into bile. We investigated the impact of hepatic ABCG5/G8
='font-weight:700;'>G8 on cholesterol metabolism and RCT. METHODS: Biliary and fecal sterol excretion (FSE) as well as RCT were determined using wild-type controls, Abcg8 knockout mice, Abcg8 knockouts with adenovirus-mediated hepatocyte-specific Abcg8 reinstitution and hepatic Abcg5/g8 overexpression in wild-types. RESULTS: In Abcg8 knockouts, biliary cholesterol secretion was decreased by 75% (p < 0.001), while mass FSE and RCT were unchanged. Hepatic reinstitution of Abcg8 increased biliary cholesterol secretion 5-fold (p < 0.001) without changing FSE or overall RCT. Overexpression of both ABCG5/G8 elevated biliary cholesterol secretion 5-fold and doubled FSE (p < 0.001) without affecting overall RCT. CONCLUSIONS: ABCG5/G8 mediate mass biliary cholesterol secretion but not from a RCT-relevant pool. Intervention strategies aiming at increasing hepatic Abcg5/g8 expression for enhancing RCT are not likely to be successful.
DuBois RN, etal., Am J Physiol. 1994 May;266(5 Pt 1):G822-7.
Growth factors have been shown to play a role in intestinal epithelial growth regulation and transformation. Utilizing standard differential cloning techniques, we have isolated a growth factor-inducible gene (RS-2) from rat intestinal epithelial cells that has approximately 95% homology to the mous
e mitogen-inducible cyclooxygenase (COX-2) at the amino acid level. This cDNA hybridizes to a approximately 4.5-kb mRNA from transforming growth factor (TGF)-alpha-stimulated rat intestinal epithelial (RIE-1) cells and is constitutively expressed in vivo in adult rat kidney and brain. Nuclear run-on experiments demonstrate that the increase of RS-2 mRNA after TGF-alpha stimulation is in part due to an increased transcription rate of the gene. The coding region for RS-2 was subcloned into a pCMV-2 expression vector, and the RS-2 protein was expressed in COS-1 cells. Microsomal fractions isolated from the COS-1 cells transfected with the RS-2 expression vector contained cyclooxygenase activity. In addition to the production of prostaglandins, the recombinant RS-2 protein also catalyzed the formation of three other eicosanoid products. In summary, we have cloned a mitogen-inducible cyclooxygenase gene from rat intestinal cells that is induced following growth factor stimulation.
Nguyen TD, etal., Am J Physiol. 1993 Nov;265(5 Pt 1):G811-8.
Pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) and PACAP-27 are recently characterized hypothalamic peptides with marked homology with vasoactive intestinal peptide (VIP), which are concentrated in the innervation of the digestive tract. We now report that, on rat liver plasma memb
ranes, PACAP interacts with at least two types of receptors: receptors demonstrating equally high affinity for PACAP and VIP and receptors with high affinity for PACAP but low affinity for VIP. In contrast, on rat intestinal epithelial cell laterobasal membranes, only receptors with high affinities for PACAP and VIP were observed. After 125I-labeled VIP or 125I-labeled PACAP-27 was cross-linked to the liver plasma membrane receptors with the use of either disuccinimidosuberate or disuccinimido dithiobis(propionate), analysis of the resulting ligand-receptor complexes on sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the structures of the VIP and PACAP receptors were similar: both ligand-receptor complexes displayed two radioactive bands with relative molecular weights of 80,000 and 56,000 under reducing conditions and of 75,000 and 53,000 under nonreducing conditions. These findings suggest that the receptors for the PACAP peptides and VIP are closely related, reflecting the marked homology between these peptides. The presence of receptors specific for PACAP on rat liver plasma membranes should stimulate further studies of the interaction between PACAP and the liver.
Meng D, etal., J Huazhong Univ Sci Technolog Med Sci. 2015 Jun;35(3):319-26. doi: 10.1007/s11596-015-1431-4. Epub 2015 Jun 14.
Many studies have reported the relationship between CXCL12 G801A polymorphism and cancer risk, with conflicting results. In this study, we tried to clarify the possibility that this polymorphism may increase cancer risk by c
onducting an updated meta-analysis. PubMed and EMbase were searched for case-control studies regarding the association of the gene polymorphism and cancer risk. Data were extracted and odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to assess the strength of the association. Heterogeneity among articles and publication bias was also assessed. Significantly increased risk for cancer was found (A vs. G: OR=1.26, 95% CI=1.13-1.40, P<0.01; AA+AG vs. GG: OR=1.33, 95% CI=1.16-1.52, P<0.01). In subgroup analysis, statistically elevated cancer risk was found in both Asian and Caucasian populations (for Asian, AA+AG vs. GG: OR=1.74, 95% CI=1.22-2.47, P<0.01; for Caucasian, AA+AG vs. GG: OR=1.24, 95% CI=1.09-1.42, P<0.01). Our result indicated that CXCL12 G801A polymorphism is a risk factor for cancer. To validate the finding, further large-size case-control studies are warranted.
Zellweger spectrum disorder (ZSD) is a disease continuum that results from inherited defects in PEX genes essential for normal peroxisome assembly. These autosomal recessive disorders impact brain development and also cause postnatal liver, adrenal, and kidney dysfunction, as well as loss of vision
and hearing. The hypomorphic PEX1-G843D missense allele, observed in approximately 30% of ZSD patients, is associated with milder clinical and biochemical phenotypes, with some homozygous individuals surviving into early adulthood. Nonetheless, affected children with the PEX1-G843D allele have intellectual disability, failure to thrive, and significant sensory deficits. To enhance our ability to test candidate therapies that improve human PEX1-G843D function, we created the novel Pex1-G844D knock-in mouse model that represents the murine equivalent of the common human mutation. We show that Pex1-G844D homozygous mice recapitulate many classic features of mild ZSD cases, including growth retardation and fatty livers with cholestasis. In addition, electrophysiology, histology, and gene expression studies provide evidence that these animals develop a retinopathy similar to that observed in human patients, with evidence of cone photoreceptor cell death. Similar to skin fibroblasts obtained from ZSD patients with a PEX1-G843D allele, we demonstrate that murine cells homozygous for the Pex1-G844D allele respond to chaperone-like compounds, which normalizes peroxisomal β-oxidation. Thus, the Pex1-G844D mouse provides a powerful model system for testing candidate therapies that address the most common genetic cause of ZSD. In addition, this murine model will enhance studies focused on mechanisms of pathogenesis.
Previous studies have demonstrated that the CXCL12 G801A polymorphism is closely correlated with tumor susceptibility. In addition, the CXCL12/CXCR4 pathway is closely related to proliferation, metastasis, and invasion of g
lioma. However, the genetic effects of the CXCL12 G801A polymorphism on glioma risk in Chinese populations remain unknown. In this study, we investigated the potential associations between the CXCL12 G801A polymorphism with glioma susceptibility and its clinicopathological characteristics. Frequencies of CXCL12 G801A polymorphic variants between glioma patients (N = 750) and healthy controls (N = 750) were assessed using restriction length fragment polymorphism analysis. The association among the CXCL12 G801A polymorphism, glioma grade (WHO classification), and histological type was also evaluated. Our results showed that patients with glioma had significantly higher frequency of the CXCL12-3' A/A genotypes (P = 0.039) as compared with healthy controls. When stratified by the glioma histology, high-grade glioma patients had significantly higher frequency of the CXCL12-3' A/A genotypes (P = 0.019) as compared with low-grade glioma patients. When stratified by the WHO grade, significantly higher frequency of the CXCL12-3' A/A genotype was observed in stage IV glioma patients (P = 0.037). We conclude that the CXCL12 G801A polymorphism is a risk factor that increases susceptibility to gliomas in a subset of the general Han Chinese population.
Froh M, etal., Am J Physiol Gastrointest Liver Physiol 2002 Oct;283(4):G856-63.
Recent studies have demonstrated that glycine blunts the response of Kupffer cells to endotoxin. Based on pharmacological evidence, it was hypothesized that Kupffer cells and other macrophages contain a glycine-gated chloride channel similar to the glycine receptor expressed in neuronal tissues. Mor
eover, glycine stimulates influx of radiolabeled chloride in Kupffer cells in a dose-dependent manner. RT-PCR was used to identify mRNA of both alpha- and beta-subunits of the glycine receptor in rat Kupffer cells, peritoneal neutrophils, and splenic and alveolar macrophages, similar to the sequence generated from rat spinal cord. Importantly, the sequence of the cloned Kupffer cell glycine receptor fragment for the beta-subunit was >95% homologous with the receptor from the spinal cord. Membranes of these cells also contain a protein that is immunoreactive with antibodies against the glycine-gated chloride channel. These data demonstrate that Kupffer cells, as well as other macrophages and leukocytes, express mRNA and protein for a glycine-gated chloride channel with both molecular and pharmacological properties similar to the channel expressed in the central nervous system.
Development and differentiation of the intestinal epithelium appear to be regulated by various growth factors. Using cDNA microarrays, we identified heparin-binding EGF-like growth factor (HB-EGF) as one of the genes induced by intestinal-specific transcription factor Cdx2 in an intestinal undiffere
ntiated rat cell line, intestinal epithelial cell (IEC)-6. Both Cdx2 and HB-EGF stimulated cell proliferation and migration, and their effects were inhibited partially by an EGF receptor-specific tyrosine kinase inhibitor, PD-153035. HB-EGF may function as one of the mediators of Cdx2 and may be associated with the proliferation and migration in the intestinal epithelium. The Cdx2 protein can bind to the Cdx2-binding element of the HB-EGF gene. Reporter gene analyses showed that the HB-EGF gene promoter is Cdx2 responsive and that the activity of the promoter in the IEC-6 cells depends on the number of consensus Cdx2-binding site-like sequences. These data indicate that HB-EGF gene expression can be regulated by Cdx2 and serves to mediate the control of Cdx2 of the proliferation and migration of IEC-6 cells.
The initial and rate-limiting step in the classic pathway of bile acid biosynthesis is 7alpha-hydroxylation of cholesterol, a reaction catalyzed by cholesterol 7alpha-hydroxylase (CYP7A1). The effect of CYP7A1 overexpression on cholesterol homeostasis in human liver cells has not been examined. The
specific aim of this study was to determine the effects of overexpression of CYP7A1 on key regulatory steps involved in hepatocellular cholesterol homeostasis, using primary human hepatocytes (PHH) and HepG2 cells. Overexpression of CYP7A1 in HepG2 cells and PHH was accomplished by using a recombinant adenovirus encoding a CYP7A1 cDNA (AdCMV-CYP7A1). CYP7A1 overexpression resulted in a marked activation of the classic pathway of bile acid biosynthesis in both PHH and HepG2 cells. In response, there was decreased HMG-CoA-reductase (HMGR) activity, decreased acyl CoA:cholesterol acyltransferase (ACAT) activity, increased cholesteryl ester hydrolase (CEH) activity, and increased low-density lipoprotein receptor (LDLR) mRNA expression. Changes observed in HMGR, ACAT, and CEH mRNA levels paralleled changes in enzyme specific activities. More specifically, LDLR expression, ACAT activity, and CEH activity appeared responsive to an increase in cholesterol degradation after increased CYP7A1 expression. Conversely, accumulation of the oxysterol 7alpha-hydroxycholesterol in the microsomes after CYP7A1 overexpression was correlated with a decrease in HMGR activity.
Aquaporin-2 (AQP-2) is the vasopressin-regulated water channel expressed in the apical membrane of principal cells in the collecting duct and is involved in the urinary concentrating mechanism. In the rat distal colon, vasopressin stimulates water absorption through an unknown mechanism. With the hy
pothesis that AQP-2 could contribute to this vasopressin effect, we studied its presence in rat colonic epithelium. We used RT-PCR, in situ hybridization, immunoblotting, and immunocytochemistry to probe for AQP-2 expression. An AQP-2 amplicon was obtained through RT-PCR of colon epithelium RNA, and in situ hybridization revealed AQP-2 mRNA in colonic crypts and, to a lesser extent, in surface absorptive epithelial cells. AQP-2 protein was localized to the apical membrane of surface absorptive epithelial cells, where it colocalized with H(+)-K(+)-ATPase but not with Na(+)-K(+)-ATPase. AQP-2 was absent from the small intestine, stomach, and liver. Water deprivation increased the hybridization signal and the protein level (assessed by Western blot analysis) for AQP-2 in distal colon. This was accompanied by increased p-chloromercuriphenylsulfonic acid-sensitive water absorption. These results indicate that AQP-2 is present in the rat distal colon, where it might be involved in a water-sparing mechanism. In addition, these results support the idea that AQP-2, and probably other aquaporins, are involved in water absorption in the colon.
Only one secretin receptor has been cloned and its properties characterized in native and transfected cells. To test the hypothesis that stimulatory and inhibitory effects of secretin are mediated by different secretin receptor subtypes, pancreatic and gastric secretory responses to secretin and sec
retin-Gly were determined in rats. Pancreatic fluid secretion was increased equipotently by secretin and secretin-Gly, but secretin was markedly more potent for inhibition of basal and gastrin-induced acid secretion. In Chinese hamster ovary cells stably transfected with the rat secretin receptor, secretin and secretin-Gly equipotently displaced (125)I-labeled secretin (IC(50) values 5.3 +/- 0.5 and 6.4 +/- 0.6 nM, respectively). Secretin, but not secretin-Gly, caused release of somatostatin from rat gastric mucosal D cells. Thus the equipotent actions of secretin and secretin-Gly on pancreatic secretion appear to result from equal binding and activation of the pancreatic secretin receptor. Conversely, secretin more potently inhibited gastric acid secretion in vivo, and only secretin released somatostatin from D cells in vitro. These results support the existence of a secretin receptor subtype mediating inhibition of gastric acid secretion that is distinct from the previously characterized pancreatic secretin receptor.
Valles-Ayoub Y, etal., Genet Test Mol Biomarkers. 2011 Jun;15(6):395-8. doi: 10.1089/gtmb.2010.0203. Epub 2011 Feb 3.
Wolman disease (WD) is a rare inherited condition caused by lysosomal acid lipase (LAL) deficiency first described in Iranian-Jewish (IJ) children. Newborns with WD are healthy and active, but soon the infant develops symptoms of severe malnutrition in the first few months of life, and often dies be
fore the age of 1 year. Harmful amounts of lipids accumulate in the spleen, liver, bone marrow, intestine, adrenal glands, and lymph nodes. Although worldwide incidence is estimated at 1/350,000 newborns, WD occurs at higher than expected frequency in the IJ community of the Los Angeles area. As a validation study, we analyzed 162 DNA specimens of IJ origin by automated sequencing. For LIPA p.G87V (ggc>gtc, alternative numbering p.G66V), a heterozygous frequency of 5/162 (3.086%) was discovered. Thus, we estimate that as high as 1 in 4200 newborns of IJ couples may be at risk. Additional studies are required to confirm and further validate the higher frequencies seen in our sample pool, and to determine if people of IJ and even possibly Middle Eastern descent are at a higher risk for WD.
Wang S, etal., Genet Mol Res. 2015 Jun 1;14(2):5856-61. doi: 10.4238/2015.June.1.2.
Cyclin D1 is an important cell cycle regulator implicated in the pathogenesis of many cancer types. In particular, translocation and overexpression of cyclin D1 are common events in multiple myeloma (MM), suggesting that it may drive the initiation and progression of this malignancy. However, the a
ssociation between genetic polymorphisms of cyclin D1 and the risk for developing MM remains poorly characterized. We performed a case-control study with 67 patients with MM and 66 healthy controls in a Chinese population. The cancer-associated G870A single nucleotide polymorphism (SNP) of CCND1, the gene encoding cyclin D1, was determined by polymerase chain reaction and restriction fragment length polymorphism. We found that there was a strong association between the homozygous variant allele (GG) and MM susceptibility, with an odds ratio (OR) of 4.679 [95% confidence interval (CI): 1.081-5.647]. When further stratified analysis was performed, the increased risk was only evident in individuals over 60 years old (OR=3.297; 95%CI: 1.058-10.276). Our results suggest that the CCND1 G870A SNP may be critically involved in MM development.
Prior studies have demonstrated that glucocorticoid hormones elicit functional maturation of the small intestine as evidenced by their ability to induce increases in the expression of various digestive hydrolases, such as sucrase-isomaltase and trehalase. However, these increases have a lag time of
approximately 24 h, suggesting that they are secondary effects of hormone action. To identify candidate primary response genes, we performed microarray analysis on pooled RNA from jejunums of untreated postnatal day 8 mouse pups and from littermates who earlier received dexamethasone 2 h. Fluorescent dye-labeled samples were hybridized in quadruplicate to glass-spotted cDNA microarrays containing 15,000 cDNA clones from the National Institute of Aging cDNA clone set. Analysis of the resulting signals using relatively stringent criteria identified 66 transcripts upregulated and 36 downregulated by 2 h of glucocorticoid treatment. Among the upregulated transcripts, the magnitude of the increase detected by microarray ranged from 1.4- to 16-fold. Selected mRNAs from throughout the range were subsequently analyzed by Northern blot analysis. Of 11 mRNAs chosen all were confirmed, and there was a strong correlation between the magnitude of the increase observed from the microarray analysis and from Northern blot analysis. Additional time points showed that these transcripts peaked between 2 and 6 h and had returned to baseline by 24 h. Gene ontology analysis showed pleiotropic effects of dexamethasone on the developing intestine and pointed to genes in the development category as being likely candidates for mediation of glucocorticoid-induced maturation of intestinal function.
Qin LY, etal., Asian Pac J Cancer Prev. 2014;15(16):6923-8.
In recent years, mounting evidence has indicated that the CCND1 G870A gene polymorphism, which impacts the mitotic cell cycle, may influence leukemia or non-Hodgkin lymphoma risk. Unfortunately, the previous results were inc
onsistent. Therefore, a meta-analysis was performed to obtain a more precise estimation of any association. We conducted a search in PubMed, Embase and CNKI covering all published papers up to March, 2014. A total of 9 publications including 10 case-control studies met the inclusion criteria. Odds ratios (ORs) and their 95% confidence intervals (95%CIs) were applied to assess association. The pooled ORs showed significant association in non-Hodgkin lymphoma (comparison A vs G: OR= 1.114, 95%CI=1.053-1.179, p=0.000; homozygote comparison AA vs GG: OR=1.245, 95%CI=1.110-1.396, p=0.000; heterozygote comparison AG vs GG: OR=1.095, 95%CI=1.000-1.199, p=0.05; dominant model AA/GA vs GG: OR=1.137, 95%CI=1.043-1.239, p=0.003; and recessive model AA vs GA/GG: OR=1.177, 95%CI=1.066-1.301, p=0.001). However, there was no association between the CCND1 G870A polymorphism and leukemia risk. In conclusion, the CCND1 G870A polymorphism may increase risk of non-Hodgkin lymphoma, but not leukemia. However, more primary large scale and well-designed studies are still required to evaluate the interaction of CCND1 G870A polymorphism with leukemia and non-Hodgkin lymphoma risk.
Wrzosek M, etal., J Physiol Pharmacol. 2015 Oct;66(5):681-9.
Hypertension is a multifactorial disease caused by environmental, metabolic and genetic factors, but little is currently known on the complex interplay between these factors and blood pressure. The aim of the present study was to assess the potential impact of obesity, and angiotensin-converting en
zyme (ACE) I/D polymorphism and endothelial nitric oxide synthase gene (NOS3) 4a/4b, G894T and -T786C variants on the essential hypertension. The study group consisted of 1,027 Caucasian adults of Polish nationality (45.5 +/- 13.6 years old), of which 401 met the criteria for hypertension. Body weight, height and blood pressure were measured and data on self-reported smoking status were collected. Fasting blood glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides were determined by standard procedures. The ACE I/D polymorphism and three polymorphisms in NOS3 gene (4a/4b, G894T, -T786C) were detected by the PCR method. Multivariable logistic regression demonstrated that age above 45 years, diabetes, dyslipidemia, smoking and male sex are important risk factors for hypertension and no significant influence of variants in ACE and NOS3 genes on this risk was recognized. Obese subjects had a 3.27-times higher risk (OR = 3.27, 95% CI: 2.37 - 4.52) of hypertension than non-obese, and in obese the NOS3 894T allele was associated with 1.37 fold higher risk of hypertension (P = 0.031). The distribution of NOS3 G894T genotypes supported the co-dominant (OR = 1.35, P = 0.034, Pfit = 0.435) or recessive (OR = 2.00, P = 0.046, Pfit = 0.286), but not dominant model of inheritance (P = 0.100). The study indicates that in obese NOS3 G894T polymorphism may enhance hypertension risk. However, in the presence of such strong risk factors as age, diabetes and smoking, the impact of this genetic variant seems to be attenuated. Further studies are needed to reveal the usefulness of G894T polymorphism in hypertension risk assessment in obese.
Necrotizing enterocolitis (NEC) is characterized by the upregulation of proinflammatory proteins, nitrosative stress, and increased enterocyte apoptosis. We examined the expression and regulation of the Bcl-2/adenovirus EIB 19-kDa-interacting protein 3 (BNIP3), a pro-apoptotic gene regulated by nitr
ic oxide (NO) in hepatocytes, in NEC. Newborn rats subjected to hypoxia and fed a conventional formula by gavage (FFH) developed NEC and demonstrated elevated expression of BNIP3 mRNA and protein in mucosal scrapings of the ileal samples and in the liver. In contrast, control rats [breast-fed (BF) without hypoxia] did not develop NEC or elevated BNIP3 expression in these tissues. BNIP3 expression paralleled the histological manifestation of NEC. Supplementation of the formula with L-Nomega-(1-iminoethyl)lysine, an inducible NO synthase inhibitor, reduced BNIP3 expression in FFH animals to the levels found in BF animals. Both hypoxia and peroxynitrite upregulated BNIP3 protein expression in human intestinal cells. Finally, ileal samples obtained from infants undergoing surgical resection for acute NEC demonstrated higher levels of BNIP3 protein. Because hypoxia and formation of reactive nitrogen species may promote gut barrier failure, we propose that upregulation of the cell death-related protein BNIP3 is one possible mechanism associated with enterocyte cell death observed in the intestine with NEC.
Chang J, etal., Am J Physiol Gastrointest Liver Physiol. 2011 May;300(5):G884-94. Epub 2011 Feb 17.
Urocortins (UCNs) and their receptors are potent immunoregulators in the gastrointestinal (GI) tract, where they can exert both pro- and anti-inflammatory effects. We examined the contribution of Ucn1 and its receptors to the pathogenesis, progression, and resolution of colitis. Trinitrobenzene sulf
onic acid was used to induce colitis in rats. Ucn1 mRNA and immunoreactivity (IR) were ubiquitously expressed throughout the GI tract under basal conditions. During colitis, Ucn1 mRNA levels fell below basal levels on day 1 then increased again by day 6, in association with an increase in the number of Ucn1-IR inflammatory cells. Ucn1-IR cells were also numerous in proliferating granulation tissue. In contrast to Ucn1 expression, average phosphorylated ERK1/2 (pERK1/2) expression rose above controls levels on day 1 and was very low on day 6 of colitis. Knockdown of corticotropin-releasing factor 2 (CRF(2)) but not CRF(1) by RNA interference during colitis significantly decreased the macroscopic lateral spread of ulceration compared with uninjected controls or animals with CRF(1) knockdown. After knockdown of CRF(2), but not of CRF(1) during colitis, edema resolution assessed microscopically was slowed, and myeloperoxidase activity remained elevated even at day 6. Ucn1 and TNF-alpha mRNA peaked earlier, whereas pERK1/2 activation was attenuated after CRF(2) knockdown. Thus we conclude that local CRF(2) and pERK1/2 activation is pivotal for macroscopic spread of colitis and resolution of edema. Elimination of CRF(2), but not CRF(1), results in uncoordinated immune and pERK1/2 signaling responses.
Garcia-Gonzalez I, etal., Clin Investig Arterioscler. 2015 Mar-Apr;27(2):64-73. doi: 10.1016/j.arteri.2014.07.002. Epub 2014 Oct 7.
INTRODUCTION AND OBJECTIVES: Cardiovascular medicine is focused on the search for genetic risk markers with predictive and/or prognostic value. Among the genetic variants of interest are G894T endothelial nitric oxide syntha
se and G1958A methylenetetrahydrofolate dehydrogenase1 gene polymorphisms. The aim of this study was to determine the possible association between these polymorphisms and ischemic heart disease in patients from Southern of Mexico (Yucatan). METHODS: Case-control study matched by age, sex and origin was designed. We studied 98 patients with coronary disease and 101 controls. Participants were evaluated for the usual risk factors. The polymorphisms were identified using the polymerase chain reaction/restriction fragment length polymorphism analysis. Informed consent was obtained from all participants. RESULTS: The G894T and G1958A polymorphisms were not associated with ischemic heart disease, however, the TT genotype (G894T) was associated with the angina (OR=10.2; 95%CI, 1.51-68.8; p=0.025). The genotype GT (G894T) was the most frequent in patients with family history of coronary artery disease. Multiple logistic regression analysis identified smoking (OR=5.21; 95%CI, 2.1-12.9; p=0.000), hypertension (OR=3.54; 95%CI, 1.47-8.56; p=0.005) and obesity (OR=1.16; 95%CI, 1.1-1.27; p=0.001) as risk factors predicting the ischemic heart disease. CONCLUSIONS: The G894T and G1958A polymorphisms showed not association with ischemic heart disease. However, homozygosis for the 894T allele (NOS3) confers at risk to develop angina on Yucatan.
Min BW, etal., Acta Neurol Belg. 2010 Sep;110(3):255-62.
OBJECTIVES: The aim of this study was to investigate whether genetic variations in the eNOS gene were associated with intracranial and extracranial atherosclerosis in Koreans. MATERIALS AND METHODS: We analyzed data on 282 consecutive Korean patients with atherosclerosis in intracranial (ICAS) or ex
tracranial vessels, and compared with 300 healthy individuals. The eNOS gene polymorphism was analyzed by PCR and direct sequencing. RESULTS: All genetic variants were single nucleotide polymorphism, two in the coding sequence (C774T and G894T) and one in intron 6. The frequency of the G894T polymorphism was significantly higher in the coronary atherosclerosis group than in the control group, but its presence did not correlate with other clinical risk factors. There was no significant difference in genotype and allele frequencies between coronary atherosclerosis and ICAS. CONCLUSION: The G894T polymorphism in the eNOS gene might influence coronary atherosclerosis rather than ICAS in Koreans.
Hu YY, etal., Diagn Pathol. 2014 Sep 10;9:168. doi: 10.1186/s13000-014-0168-x.
BACKGROUND: Association between Cyclin D1 (CCND1) polymorphism and cervical cancer risk are conflicting with published articles. We performed a meta-analysis to investigate the association between CCND1 G870A poly
morphism and cervical cancer risk. METHODS: PubMed, Embase and CNKI data were researched to conduct a meta-analysis on the associations between CCND1 G870A polymorphism and cervical cancer risk. Ten published case-control studies including 2,864 patients with cervical cancer and 3,898 controls were collected in this meta-analysis. Odds ratio (OR) with 95% confidence interval (CI) were applied to assess the relationship; meta-regression, sensitivity analysis and cumulative analysis were also conducted to guarantee the strength of results. RESULTS: Overall, no significant association between CCND1 G870A polymorphism and cervical cancer risk were found in allele contrast (A vs. G: OR=1.02, 95% CI=0.88-1.19, P=0.76 I2=74.5%), codominant model (GA vs. GG: OR=0.98, 95% CI=0.77-1.26, P=0.90 I2=69.1%; AA vs GG: OR=1.03, 95% CI=0.75-1.41, P=0.85 I2=75.9%), dominant model (GA + AA vs. GG: OR=1.00, 95% CI=0.78-1.28, P=0.99 I2=72.3%) and recessive model (AA vs GG + GA: OR=1.06, 95% CI=0.85-1.23, P=0.62, I2=70.1%). Similarly, in the stratified analysis by ethnicity, study design and genotyping type, no significant association detected in all genetic models either. CONCLUSIONS: Our meta-analysis indicated that CCND1 G870A might be not the crucial risk factor for the development of cervical cancer. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_168.
Lu HX, etal., Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2015 Nov;31(6):517-23.
OBJECTIVE: Highland natives adapt well to the hypoxic environment at high altitude (HA). Several genes have been reported to be linked to HA adaptation. Previous studies showed that the endothelial ni- tric oxide synthase (ENOS) G8
94T polymorphism contributed to the physiology and pathophysiology of hu- mans at HA by regulating the production of NO. In this meta-analysis, we evaluate the association between the ENOS G894T polymorphism and HA adaptation through analyzing the published data. METHODS: We searched all relevant literature about the ENOS G894T polymorphism and HA adaptation in PubMed, Med- line, and Embase before Step 2015. A random-effects model was applied (Revman 5.0), and study quality was assessed in duplicate. Six studies with 634 HA native cases and 621 low-altitude controls were included in this meta-analysis. RESULTS: From the results, we observed that the wild-type allele G was significantly overrepresented in the HA groups (OR = 1.85; 95% Cl, 1.47-2.33; P < 0.0001). In addition, the GG genotype was significantly associated with HA adaptation (OR = 1.99; 95% Cl, 1.54-2.57; P < 0.0001). CONCLUSION: Our results showed that in 894 G allele carriers, the GG genotype might be a beneficial factor for HA adaptation through enhancing the level of NO. However, more studies were needed to confirm our findings due to the limited sample size.
BACKGROUND: The receptor for advanced glycation end products (RAGE) plays an important role in the pathogenesis of diabetic complications. The aim of this study is to investigate the association of the 1704 G/T and G82S poly
morphisms in the RAGE gene with diabetic retinopathy (DR). METHODS: The 1704G/T and G82S polymorphisms were genotyped in 340 Type 2 diabetes (T2DM) without DR subjects (DR- group); 166 T2DM with DR subjects (DR+ group), and 182 normal glucose tolerant subjects (NGT group). The genotypes were detected by the methods of ligase detection reaction coupled PCR. RESULTS: There was no evident difference in the 1704G/T and G82S genotypic and allelic frequencies distribution between NGT and T2DM subjects. However, the frequences of G/A+AA genotypes (60.6%) and A allele (36.4%) of G82S were significantly higher in DR+ group than those (38.4%; 20.9%, respectively) in DR- group (p=0.01and p=0.007, respectively). Furthermore, haplotype analysis revealed that the frequency of G-A haplotype containing 1704G and 82S allele in DR+ group was significantly higher than that in DR- group (33.5% vs 19.6%, p=0.01). The multiple logistic regression analysis indicated that the G82S polymorphism [odds ratio (OR): 2.964, 95% confidence interval (CI): 1.013-5.46, p=0.029] and diabetes duration (OR: 1.013, 95% CI: 1.007-1.02, p<0.001) were independent risk factors for DR. CONCLUSIONS: G82S polymorphism in the RAGE gene is associated with DR and G-A haplotype containing 1704G and 82S allele might be a genetic marker of DR in Chinese T2DM patients.
OBJECTIVE: Pregnancy-induced hypertension is one of the most important cause of maternal-fetal morbidity and mortality. Pregnancy-related hypertensive disorders are usually associated with diminished nitric oxide (NO) levels. We aimed to evaluate the role of serum NO levels and eNOS gene G8
e='font-weight:700;'>G894T polymorphism on hypertensive disorders of pregnancy. METHODS: Eighty patients with gestational hypertension or preeclampsia, and 80 healthy pregnants were enrolled to analyze serum NO levels and G894T polymorphism of the eNOS gene. NO level was analyzed by high-performance liquid chromatography (HPLC) method. The G894T polymorphism of the eNOS gene was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). RESULTS: There was no significant difference between groups in terms of G894T/eNOS genotype and allele frequencies (p > 0.05). Serum NO levels were significantly lower in the patients group. In the control group, subjects with thymine-thymine (TT) genotype had significantly lower NO levels when compared to subjects with guanine-guanine (GG) or guanine-thymine (GT) genotype (p < 0.05). CONCLUSIONS: We failed to demonstrate an association between eNOS gene G894T polymorphism and serum NO levels in patients with pregnancy-induced hypertensive disorders. We established a relation between pregnancy-induced hypertension and low NO levels.
PURPOSE: Cyclin D1 (CCND1) mRNA is alternatively spliced to produce 2 transcripts (transcript-a and transcript-b), which may be modulated by a G870A single nucleotide polymorphism at the conserved splice donor site of exon 4
. Previous studies have suggested a significant association between the CCND1 genotype and the development of various cancers. We explored the possible association between this polymorphism and the onset or disease statue of sporadic renal cell carcinoma (RCC). MATERIALS AND METHODS: The CCND1 G870A genotype was determined in 191 RCC cases and in 400 controls by polymerase chain reaction restriction length polymorphism analysis. RESULTS: Subjects with the AA genotype were at 1.70-fold significant higher risk for RCC than those with the GG genotype (age and sex adjusted OR 1.70, 95% 95% CI 1.03 to 2.82, p = 0.039). In addition, the A allele had a gene dose effect in increasing the risk of RCC (adjusted OR 1.30, 95% CI 1.01 to 1.67, p = 0.045). For tumor stage no significant difference in genotype frequency was found (p = 0.646). CONCLUSIONS: These data suggest that the CCND1 variant A allele may be a genetic susceptibility factor with a recessive or gene dose effect for the onset of sporadic RCC. More extensive and larger studies are required to clarify whether the CCND1 genotype is more specifically involved in the onset of a histological subset of RCC or RCC at a younger age.
Thrombosis is a common complication of Behcet disease and the pathogenic mechanism of thrombotic tendency in Behcet disease is not well known. Several platelet membrane glycoprotein gene polymorphisms have been identified as risk factors for thrombosis. This study aimed to evaluate the possible role
of the GP Ia C807T/G873A polymorphism as a risk factor for thrombosis in Behcet disease. We determined the prevalence of platelet glycoprotein Ia C807T/G873A gene polymorphism in Behcet patients. Genomic DNA was obtained from 20 patients with Behcet disease and 61 controls. All individuals were of Turkish ancestry and were genotyped for the GP Ia C807T/G873A polymorphism with real-time PCR method by LightCycler system. The 807 CC, CT and TT genotypes corresponded with 873 GG, GA and AA genotypes, respectively. Complete linkage between the 807 and 873 sites was found in all samples. The 807CC(873 GG), 807CT(873GA), 807TT(873AA) genotypes found to be 45.9%, 45.9% and 8.1% in controls and 30.0%, 55.0% and 15.0% in patients with Behcet disease, respectively. The Odds Ratio for BD (OR = 1.97; 95% confidence interval (CI): 0.42-9.13) is high for the 807 TT genotype compared with controls. Thrombosis was found in 7 cases of Behcet disease group: five cases have 807CT, one case has 807TT genotype and one case has 807CC genotype. Our data indicate hat patients with BD are affected by the glycoprotein Ia gene 807TT genotypes and carrying 807T allele. The risk of thrombosis is significantly higher in patients who have 807TT and 807CT genotypes than in patients who have 807CC genotype.
Transforming growth factor-ß1 (TGF-ß1) is a multifunctional pro-inflammatory cytokine involved in inflammation and pathogenesis of cerebrovascular disease. As per our knowledge, there is no published study investigating the association between variations within the TGF-ß1 gene polymorphisms and risk
of intracerebral hemorrhage (ICH). The aim of this study was to investigate the association of the TGF-ß1 gene (C509T, G800A and T869C) polymorphisms, and their haplotypes with the risk of ICH in North Indian population. 100 ICH patients and 100 age- and sex-matched controls were studied. Genotyping was performed using SNaPshot method. Conditional logistic regression analysis was used to calculate the strength of association between TGF-ß1 gene polymorphisms and risk of ICH. Hypertension, diabetes, dyslipidemia, low socioeconomic status, smoking, physical activity were found to be associated with the risk of ICH. The distribution of C509T, G800A and T869C genotypes was consistent with Hardy-Weinberg Equilibrium (HWE) in the ICH and control group. Adjusted conditional logistic regression analysis showed an independent association of TGF-ß1 G800A (OR 9.07; 95% CI 2.3-35.6; P = 0.002) and T869C (OR 5.1; 95 % CI 1.9-13.2; P = 0.001) with the risk of ICH under dominant model. Haplotype analysis showed that C509-G800-C869 and C509-A800-C869 haplotypes were significantly associated with the increased risk of ICH. C509T and T869C were in strong linkage disequilibrium (D' = 0.53, r(2) = 0.23). Our results suggest that TGF-ß1 (G800A, T869C) gene polymorphisms and their haplotypes are significantly associated with the risk of ICH in North Indian population. Further prospective studies with large sample size are required for independent validation. Our findings could be helpful in identifying individuals at increased risk for developing ICH.
Henskens LH, etal., Stroke. 2005 Sep;36(9):1869-73. Epub 2005 Aug 18.
BACKGROUND AND PURPOSE: Silent white matter lesions (WMLs) may represent early target organ damage of the brain in patients with hypertension. Because these lesions may have a genetic background, we assessed the associations between polymorphisms of the renin-angiotensin system and the endothelial N
O synthase (NOS3) genes and silent WMLs. METHODS: Ninety-three hypertensive individuals were studied. MRI of the brain was performed to obtain estimates of the total volume of subcortical and the extent of periventricular WMLs. Patients were genotyped for the angiotensinogen (M235T), the angiotensin-converting enzyme (insertion/deletion [I/D]), the angiotensin II type 1 receptor (AGTR1 A1166C), and the NOS3 (G894T) genes. A linear regression model was used to assess the relationship of these gene polymorphisms with both subtypes of WMLs. RESULTS: When adjusted for age, diabetes mellitus, and blood pressure, subcortical WML volume was lowest in the presence of 1 or 2 AGTR1 C alleles (unstandardized beta, -38.8 [95% CI, -66.1 to -11.4] and -112.6 [CI, -188.9 to -36.4], respectively), whereas it was highest in the presence of an NOS3 T allele (31.1[corrected] [CI, 3.6 to 58.4]). No interaction between these polymorphisms on WMLs could be demonstrated. No associations were present with the other polymorphisms, either with subcortical or periventricular lesions. CONCLUSIONS: We found the AGTR1 A1166C as well as the NOS3 G894T polymorphisms to be associated with silent WMLs in the subcortical area.
BACKGROUND: The endothelial nitric oxide synthase (eNOS) G894T gene polymorphism is associated with the risk of primary hypertension (PH) and vascular complications in adults with PH. METHODS: We explored the associations o
f the G894T polymorphism with 24-h ambulatory blood pressure, left ventricular mass (LVM), carotid intima media thickness (cIMT), urinary albumin excretion, oxidative stress and inflammatory parameters in 126 children with newly diagnosed PH and in 83 healthy children. RESULTS: Among the 126 children with PH 92 (73%) had ambulatory hypertension and 34 (27%) had severe ambulatory hypertension. Left ventricular hypertrophy (LVH) was detected in 39 (31%) patients, cIMT of >2 standard deviation scores in 21 (16.6%) patients, albuminuria of >30 mg/24 h in 18 (14.3%) patients and metabolic syndrome (MS) in 22 (17.5%) patients. The frequency of the T allele was 52.4% in the PH group and 54.2% in the control group (not significant), and in both groups the frequency of the T allele was consistent with the Hardy-Weinberg equilibrium. Compared with G allele carriers, hypertensive T allele carriers had increased cIMT (p < 0.05) and more severe albuminuria (not significant, p = 0.1); there was no difference between the groups in hypertension severity and LVM. T and G allele distribution did not differ between patients with and without metabolic syndrome. No significant correlations between the assessed parameters and the eNOS G894T gene polymorphism were found in the controls, although T allele carriers tended to have an increased cIMT (p = 0.09). CONCLUSION: The eNOS T allele is not more prevalent among hypertensive children than among healthy ones, but it is associated with early vascular damage in children with PH, independent of metabolic abnormalities. No associations between the eNOS G894T polymorphism and metabolic abnormalities were found.
Duncan M, etal., Am J Physiol Gastrointest Liver Physiol. 2008 Jul;295(1):G78-G87. Epub 2008 May 15.
Enhanced intestinal transit due to lipopolysaccharide (LPS) is reversed by cannabinoid (CB)2 receptor agonists in vivo, but the site and mechanism of action are unknown. We have tested the hypothesis that CB2 receptors are expressed in the enteric nervous system and are activated in pathophysiologic
al conditions. Tissues from either saline- or LPS-treated (2 h; 65 microg/kg ip) rats were processed for RT-PCR, Western blotting, and immunohistochemistry or were mounted in organ baths where electrical field stimulation was applied in the presence or absence of CB receptor agonists. Whereas the CB2 receptor agonist JWH133 did not affect the electrically evoked twitch response of the ileum under basal conditions, in the LPS-treated tissues JWH133 was able to reduce the enhanced contractile response in a concentration-dependent manner. Rat ileum expressed CB2 receptor mRNA and protein under physiological conditions, and this expression was not affected by LPS treatment. In the myenteric plexus, CB2 receptors were expressed on the majority of neurons, although not on those expressing nitric oxide synthase. LPS did not alter the distribution of CB2 receptor expression in the myenteric plexus. In vivo LPS treatment significantly increased Fos expression in both enteric glia and neurons. This enhanced expression was significantly attenuated by JWH133, whose action was reversed by the CB2 receptor antagonist AM630. Taking these facts together, we conclude that activation of CB2 receptors in the enteric nervous system of the gastrointestinal tract dampens endotoxin-induced enhanced intestinal contractility.
Chen X, etal., DNA Cell Biol. 2012 Jun;31(6):1107-13. doi: 10.1089/dna.2011.1521. Epub 2012 Feb 3.
A common polymorphism (G870A) in the exon 4/intron 4 boundary of CCND1 gene has been linked to an alternate transcript, cyclin D1b, which preferentially encodes a protein with an increased transforming capability compared wi
th the full-length D1a. Therefore, the CCND1 G870A polymorphism may influence an individual's susceptibility to the development of certain tumors. In the present study, we investigated the association of CCND1 G870A polymorphism with glioma cancer risk in a northern Chinese population. By polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, CCND1 G870A genotyping was carried out among 170 glioma patients and 170 age, gender-matched healthy control subjects. The CCND1 870 A allele was more frequently observed in patients than in controls (0.57 vs. 0.48, p=0.03), and an increased risk of glioma cancer was observed for the AA genotype compared with the GG and AG genotypes (odds ratio [OR]=1.828; 95% confidence interval [CI]: 1.150-2.908, p=0.01), particularly among female groups, or ages <=45 groups (OR=2.204, 95% CI: 1.220-3.981, p=0.008). Significant associations were also observed between the AA genotype and glioma risk in the subgroups of World Health Organization (WHO) grade II gliomas and grade III gliomas. Further reverse transcriptase-polymerase chain reaction analysis (RT-PCR) also revealed a stronger positive correlation between the AA genotype and higher cyclin D1b expression among glioma patients either in the mean quantitative value, or the cyclin D1b/cyclin D1a ratio in the same tumor tissue (p=0.008, p=0.004, respectively). In conclusion, our data indicate that the CCND1 G870A polymorphism modulated oncogenic cyclin D1b expression in glioma tissues and may be associated with an increased risk of gliomas in Chinese population.
Riehl TE, etal., Am J Physiol Gastrointest Liver Physiol. 2015 Dec 1;309(11):G874-87. doi: 10.1152/ajpgi.00123.2015. Epub 2015 Oct 1.
Hyaluronic acid, a glycosaminoglycan in the extracellular matrix, binds to CD44 and Toll-like receptor 4 (TLR4). We previously addressed the role of hyaluronic acid in small intestinal and colonic growth in mice. We addressed the role of exogenous hyaluronic acid by giving hyaluronic acid intraperit
oneally and the role of endogenous hyaluronic acid by giving PEP-1, a peptide that blocks hyaluronic acid binding to its receptors. Exogenous hyaluronic acid increased epithelial proliferation but had no effect on intestinal length. PEP-1 resulted in a shortened small intestine and colon and diminished epithelial proliferation. In the current study, we sought to determine whether the effects of hyaluronic acid on growth were mediated by signaling through CD44 or TLR4 by giving exogenous hyaluronic acid or PEP-1 twice a week from 3-8 wk of age to wild-type, CD44(-/-), and TLR4(-/-) mice. These studies demonstrated that signaling through both CD44 and TLR4 were important in mediating the effects of hyaluronic acid on growth in the small intestine and colon. Extending our studies to early postnatal life, we assessed the effects of exogenous hyaluronic acid and PEP-1 on Lgr5(+) stem cell proliferation and crypt fission. Administration of PEP-1 to Lgr5(+) reporter mice from postnatal day 7 to day 14 decreased Lgr5(+) cell proliferation and decreased crypt fission. These studies indicate that endogenous hyaluronic acid increases Lgr5(+) stem cell proliferation, crypt fission, and intestinal lengthening and that these effects are dependent on signaling through CD44 and TLR4.
Hermann S, etal., Am J Med Genet. 2000 Mar 6;91(1):68-73.
Metachromatic leukodystrophy is a lysosomal storage disease caused by the deficiency of arylsulfatase A. Here we describe a hitherto unknown arylsulfatase A allele carrying a E312D missense mutation and characterize the effects of this and three previously described missense mutations, G8
='font-weight:700;'>G86D, Y201C, and D255H, on arylsulfatase A. In transfection experiments no enzyme activity can be expressed from arylsulfatase A cDNAs coding for the D255H substituted enzyme, whereas Y201C and E312D mutations were associated with low amounts of residual enzyme activity. All amino acid substitutions lead to a decreased stability of the mutant enzyme, and metabolic labeling experiments indicated that except for the E312D substitution the mutations cause arrest of the mutant arylsulfatase A polypeptides in a prelysosomal compartment.
Weiser B, etal., Am J Physiol Gastrointest Liver Physiol. 2011 May;300(5):G815-22. doi: 10.1152/ajpgi.00108.2010. Epub 2011 Feb 24.
Chronic ethanol feeding is known to negatively impact hepatic energy metabolism. Previous studies have indicated that the underlying lesion responsible for this may lie at the level of the mitoribosome. The aim of this study was to characterize the structure of the hepatic mitoribosome in alcoholic
male rats and their isocalorically paired controls. Our experiments revealed that chronic ethanol feeding resulted in a significant depletion of both structural (death-associated protein 3) and functional [elongation factor thermo unstable (EF-Tu)] mitoribosomal proteins. In addition, significant increases were found in nucleotide elongation factor thermo stable (EF-Ts) and structural mitochondrial ribosomal protein L12 (MRPL12). The increase in MRPL12 was found to correlate with an increase in the levels of the 39S large mitoribosomal subunit. These changes were accompanied by decreased levels of nuclear- and mitochondrially encoded respiratory subunits, decreased amounts of intact respiratory complexes, decreased hepatic ATP levels, and depressed mitochondrial translation. Mathematical modeling of ethanol-mediated changes in EF-Tu and EF-Ts using prederived kinetic data predicted that the ethanol-mediated decrease in EF-Tu levels could completely account for the impaired mitochondrial protein synthesis. In conclusion, chronic ethanol feeding results in a depletion of mitochondrial EF-Tu levels within the liver that is mathematically predicted to be responsible for the impaired mitochondrial protein synthesis seen in alcoholic animals.
Satinder K, etal., Mol Cell Biochem. 2008 Jun 12;.
Cyclin D1 (CCND1) is a key regulatory protein, playing a critical role in the transition from G1 to S phase of the cell cycle. We have evaluated the association between CCND1 A870G polymorphism and risk of cervix cancer in north Indian women by using PCR-RFLP method. This association was estimated b
y computing odds ratio (ORs) and a 95% Confidence Intervals (95% CI) using a Multivariate Logistic Regression Analysis. No significant association was observed between CCND1 genotypes and overall risk of cervix cancer. But when stratified histologically, statistically significant (OR: 3.7, 95% CI: 1.56-8.87, P: 0.001) increased risk of squamous cell carcinoma (SCC) was observed for individuals with AA genotype. Thus our findings suggest that CCND1 (G870A) polymorphism may be associated with increased risk of SCC of the uterine cervix in north Indian women.
Zhao Y, etal., Genet Mol Res. 2015 May 18;14(2):5171-80. doi: 10.4238/2015.May.18.7.
Cyclin D1 (CCND1) is a key protein involved in cell-cycle regulation, and the CCND1 G870A polymorphism is associated with many types of malignancy. Studies examining the associations between this G8
;'>G870A polymorphism and susceptibility to leukemia and hepatocellular carcinoma (HCC) have shown inconsistent results. Therefore, we conducted a meta-analysis to clarify these associations. A search of the PubMed database yielded 7 relevant articles: 3 pertaining to leukemia and 4 to HCC. The odds ratios (ORs) from individual studies were pooled using a fixed or random-effect model. A significant association was observed between the CCND1 G870A variant and leukemia under the allele contrast model [P = 0.003, OR = 1.49, 95% confidence interval (CI) = 1.15-1.95], the homozygote contrast model (P = 0.003, OR = 2.30, 95%CI = 1.34-3.96), and the recessive model (P = 0.002, OR = 2.03, 95%CI = 1.29-3.21). A significant association was observed between this variant and HCC under the recessive model (P = 0.0006, OR = 1.62, 95%CI = 1.23-2.14), the dominant model (P = 0.002, OR = 1.59, 95%CI = 1.19-2.14), the homozygote contrast model (P < 0.0001, OR = 2.06, 95%CI = 1.45-2.94), and the allele contrast model (P < 0.0001, OR = 1.43, 95%CI = 1.20-1.69). Our findings suggest that heritable CCND1 status may influence the risk of developing leukemia and HCC, and that more attention should be given to carriers of these susceptibility genes.
BACKGROUND AND OBJECTIVE: Cyclin D1 is an important regulator protein for the G1-S cell cycle phase transition. The aim of this trial was to evaluate the impact of the CCND1 polymorphism G870A and corresponding pr
otein expression and CCND1 amplification on the survival of the patients. METHODS: 425 patients with ductal pancreatic adenocarcinoma who underwent resection were included after histopathological confirmation. DNA was analyzed for Cyclin D1 polymorphisms, immunhistochemical examination and fluorescence in situ hybridization analysis of the tumor were performed. RESULTS: Overall, the mean survival was 22.9 months (20.5-25.3). The survival in patients with Cyclin D1 G870A polymorphism Adenine/Adenine was 15.1 months (95% CI 11.3-18.9), 21.5 months (17.4-25.6) for Adenine/Guanine, and 29.4 months (95% CI 23.8-35.0) for Guanine/Guanine (P¿=¿0.003). A shorter survival was associated with strong/moderate protein expression in immunohistochemistry (IHC) compared to weak/no expression (P¿=¿0.028). Additionally, a significant coherency between unfavourable polymorphism (AA/AG) and increased protein expression was detected (P¿=¿0.005). CONCLUSIONS: A strong impact on survival of Cyclin D1 G870A polymorphism and the detected corresponding protein expression was found. The biological mechanism of CCND1 in carcinogenesis has not been fully examined; but at present Cyclin D1 seems to be an interesting biomarker for the prognosis of ductal adenocarcinoma.
INTRODUCTION: Hantavirus infections are characterized by both activation and dysfunction of the endothelial cells. The underlying mechanisms of the disease pathogenesis are not fully understood. Here we tested the hypothesis whether the polymorphisms of endothelial nitric oxide synthase, eNOS G8
style='font-weight:700;'>G894T, and inducible nitric oxide synthase, iNOS G2087A, are associated with the severity of acute Puumala hantavirus (PUUV) infection. PATIENTS AND METHODS: Hospitalized patients (n = 172) with serologically verified PUUV infection were examined. Clinical and laboratory variables reflecting disease severity were determined. The polymorphisms of eNOS G894T (Glu298Asp, rs1799983) and iNOS G2087A (Ser608Leu, rs2297518) were genotyped. RESULTS: The rare eNOS G894T genotype was associated with the severity of acute kidney injury (AKI). The non-carriers of G-allele (TT-homozygotes) had higher maximum level of serum creatinine than the carriers of G-allele (GT-heterozygotes and GG-homozygotes; median 326, range 102-1041 vs. median 175, range 51-1499 mumol/l; p = 0.018, respectively). The length of hospital stay was longer in the non-carriers of G-allele than in G-allele carriers (median 8, range 3-14 vs. median 6, range 2-15 days; p = 0.032). The rare A-allele carriers (i.e. AA-homozygotes and GA-heterozygotes) of iNOS G2087A had lower minimum systolic and diastolic blood pressure than the non-carriers of A-allele (median 110, range 74-170 vs.116, range 86-162 mmHg, p = 0.019, and median 68, range 40-90 vs. 72, range 48-100 mmHg; p = 0.003, respectively). CONCLUSIONS: Patients with the TT-homozygous genotype of eNOS G894T had more severe PUUV-induced AKI than the other genotypes. The eNOS G894T polymorphism may play role in the endothelial dysfunction observed during acute PUUV infection.
Yu LC, etal., Am J Physiol Gastrointest Liver Physiol. 2014 Oct 15;307(8):G824-35. doi: 10.1152/ajpgi.00070.2014. Epub 2014 Jul 24.
Antibiotic usage promotes intestinal colonization of antibiotic-resistant bacteria. However, whether resistant bacteria gain dominance in enteric microflora or disseminate to extraintestinal viscera remains unclear. Our aim was to investigate temporal diversity changes in microbiota and transepithel
ial routes of bacterial translocation after antibiotic-resistant enterobacterial colonization. Mice drinking water with or without antibiotics were intragastrically gavaged with ampicillin-resistant (Amp-r) nonpathogenic Escherichia coli (E. coli) and given normal water afterward. The composition and spatial distribution of intestinal bacteria were evaluated using 16S rDNA sequencing and fluorescence in situ hybridization. Bacterial endocytosis in epithelial cells was examined using gentamicin resistance assay and transmission electromicroscopy. Paracellular permeability was assessed by tight junctional immunostaining and measured by tissue conductance and luminal-to-serosal dextran fluxes. Our results showed that antibiotic treatment enabled intestinal colonization and transient dominance of orally acquired Amp-r E. coli in mice. The colonized Amp-r E. coli peaked on day 3 postinoculation and was competed out after 1 wk, as evidenced by the recovery of commensals, such as Escherichia, Bacteroides, Lachnospiraceae, Clostridium, and Lactobacillus. Mucosal penetration and extraintestinal dissemination of exogenous and endogenous enterobacteria were correlated with abnormal epithelial transcytosis but uncoupled with paracellular tight junctional damage. In conclusion, antibiotic-induced enteric dysbiosis predisposes to exogenous infection and causes systemic dissemination of both antibiotic-resistant and commensal enterobacteria through transcytotic routes across epithelial layers. These results may help explain the susceptibility to sepsis in antibiotic-resistant enteric bacterial infection.
Nagy M, etal., Proc Natl Acad Sci U S A. 2016 May 10;113(19):5424-8. doi: 10.1073/pnas.1604885113. Epub 2016 Apr 25.
Recent studies have indicated that mammalian cells contain a cytosolic protein disaggregation machinery comprised of Hsc70, DnaJ homologs, and Hsp110 proteins, the last of which acts to accelerate a rate-limiting step of nucleotide exchange of Hsc70. We tested the ability of transgenic overexpress
ion of a Thy1 promoter-driven human Hsp110 protein, HspA4L (Apg1), in neuronal cells of a transgenic G85R SOD1YFP ALS mouse strain to improve survival. Notably, G85R is a mutant version of Cu/Zn superoxide dismutase 1 (SOD1) that is unable to reach native form and that is prone to aggregation, with prominent YFP-fluorescent aggregates observed in the motor neurons of the transgenic mice as early as 1 mo of age. The several-fold overexpression of Hsp110 in motor neurons of these mice was associated with an increased median survival from approximately 5.5 to 7.5 mo and increased maximum survival from 6.5 to 12 mo. Improvement of survival was also observed for a G93A mutant SOD1 ALS strain. We conclude that neurodegeneration associated with cytosolic misfolding and aggregation can be ameliorated by overexpression of Hsp110, likely enhancing the function of a cytosolic disaggregation machinery.
Fletcher JA, etal., Am J Physiol Gastrointest Liver Physiol. 2016 May 15;310(10):G832-43. doi: 10.1152/ajpgi.00355.2015. Epub 2016 Mar 24.
Exercise stimulates hepatic mitochondrial adaptations; however, the mechanisms remain largely unknown. Here we tested whether FGF21 plays an obligatory role in exercise induced hepatic mitochondrial adaptations by testing exercise responses in FGF21 knockout mice. FGF21 knockout (FGF21-KO) and wil
d-type (WT) mice (11-12 wk of age) had access to voluntary running wheels for exercise (EX) or remained sedentary for 8 wk. FGF21 deficiency resulted in greater body weight, adiposity, serum cholesterol, insulin, and glucose concentrations compared with WT mice (P < 0.05). In addition, hepatic mitochondrial complete palmitate oxidation, beta-hydroxyacyl-CoA dehydrogenase (beta-HAD) activity, and nuclear content of PGC-1alpha were 30-50% lower in FGF21-KO mice compared with WT mice (P < 0.01). EX effectively lowered body weight, adiposity, serum triglycerides, free fatty acids, and insulin and normalized mitochondrial complete palmitate oxidation in the FGF21-KO mice, whereas the reduced hepatic beta-HAD activity and lowered nuclear content of PGC-1alpha in FGF21-KO mice were not restored by EX. In addition, EX increased hepatic CPT-1alpha mRNA expression and ACC phosphorylation (a marker of increased AMPK activity) and reduced hepatic triacylglycerol content in both genotypes. However, FGF21-KO mice displayed a lower EX-induced increase in the mRNA expression of the hepatic gluconeogenic gene, PEPCK, compared with WT. In conclusion, FGF21 does not appear necessary for exercise-induced systemic and hepatic mitochondrial adaptations, but the increased adiposity, hyperinsulinemia, and impairments in hepatic mitochondrial function induced by FGF21 deficiency can be partially rescued by daily wheel running exercise.
Pandey A, etal., Tumori. 2017 Dec 1:tj5000707. doi: 10.5301/tj.5000707.
Purpose The purpose of this study was to investigate the potential role of the cyclin D1 gene G870A polymorphism in the likelihood of the development of lung cancer and the overall survival of lung cancer patients in the Nor
th Indian population. Methods The study consisted of 353 lung cancer cases and 351 age- and gender-matched healthy controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLPP) was done for the CCND1 gene. The association analysis was done using the multiple linear regression, and the survival analysis was done using the Kaplan-Meier and the Cox regression models. Results The GA genotype was associated with an increased risk for overall lung cancer (odds ratio [OR] = 1.63; p = 0.01). Combined variant genotype showed a significant association for overall lung cancer (OR 1.50; p = 0.03). In addition, smokers with the carrier genotype of CCND1 were found to have a significantly higher risk for lung cancer (OR 1.57; p = 0.04). No significant correlation was observed between the overall survival of lung cancer patients and CCND1 polymorphism. However, on stratifying the subjects on the basis of histology, it was evident that small-cell lung cancer (SCLC) patients carrying the mutant (AA) genotype showed nearly a fivefold increased mortality rate compared to the wild (GG) genotype (p = 0.03). Conclusions Our results suggest that polymorphic CCND1 may increase the risk of lung cancer in smokers from North India, and it may be associated with the overall survival of SCLC patients.
Shtilbans A, etal., J Child Neurol. 2000 Nov;15(11):759-61.
We identified a G-->A transition at nt-8363 in the mitochondrial DNA transfer ribonucleic acidLys gene in blood and muscle from a 13-month-old girl who had clinical and neuroradiologic evidence of Leigh syndrome and died at age 27 months. The mutation was less abundant in the same tissues from the p
atient's mother, who developed myoclonus epilepsy with ragged red fibers (MERRF) in her late 20s. In both mother and daughter, muscle histochemistry showed ragged red and cytochrome c oxidase-negative fibers and biochemical analysis showed partial defects of multiple respiratory-chain enzymes. A maternal half-sister of the proband had died at 2.5 years of age from neuropathologically proven Leigh syndrome. The G8363A mutation, which previously had been associated with cardiomyopathy and hearing loss, MERRF, and multiple lipomas, also should be included in the differential diagnosis of maternally inherited Leigh syndrome.
Having in mind the relationships among oxidative stress, psoriasis and common disorders, the association between polymorphisms in the gene encoding the receptor for advanced glycation end products (RAGE) and plaque psoriasis, including patients with a personal history of diabetes mellitus, cardiovas
cular disorders, cancer and allergy, was investigated. The allele frequencies and genotype distribution combinations of the four polymorphisms in the RAGE gene (6p21.3, G82S, 1704G/T, 2184A/G and 2245A/G) were compared in a case-control study of 272 subjects (130 patients with plaque psoriasis and 142 healthy control subjects of comparable age and sex distribution). The polymerase chain reaction with subsequent restriction analysis was used for detection of genotype variants. There was a significantly higher frequency of the 2184G allele of the 2184A/G RAGE polymorphism in psoriatic patients than in the control subjects (odds ratio 2.18, 95% CI 1.32-3.59, P=0.001). The 2184G allele occurred more often in psoriatic patients with a negative history of cardiovascular diseases (odds ratio 2.38, 95% CI 1.35-4.18, P=0.001, Pcorr=0.004), in those with a negative history of diabetes mellitus (odds ratio 2.05, 95% CI 0.1.22-3.45, P=0.004, Pcorr=0.012) and in those with a negative history of cancer (odds ratio 1.97, 95% CI 1.17-3.31, P=0.007, Pcorr=0.014) compared with the corresponding control subjects. We conclude that the 2184G allele of the RAGE gene is a significant risk factor for plaque psoriasis. The risk is associated with the non-presence of some common, especially cardiovascular, diseases in psoriatic patients.
Yeh KY, etal., Am J Physiol Gastrointest Liver Physiol. 2011 Jul;301(1):G82-90. doi: 10.1152/ajpgi.00538.2010. Epub 2011 Mar 24.
The divalent metal transporter (DMT1, Slc11a2) is an important molecule for intestinal iron absorption. In the Belgrade (b/b) rat, the DMT1 G185R mutation markedly decreases intestinal iron absorption. We used b/b rats as a model to examine the genes that could be compensatory for decreased iron abs
orption. When tissue hypoxia was assayed by detecting pimonidazole HCl adducts, the b/b liver and intestine exhibited more adducts than the +/+ rats, suggesting that hypoxia might signal altered gene expression. Total RNA in the crypt-villus bottom (C-pole) and villus top (V-pole) of +/+, b/b, and iron-fed b/b rats was isolated for gene array analyses. In addition, hepatic hepcidin and intestinal hypoxia-inducible factor-α (Hifα) expression were examined. The results showed that expression of hepatic hepcidin was significantly decreased and intestinal Hif2α was significantly increased in b/b and iron-fed b/b than +/+ rats. In b/b rats, the expression of Tfrc mRNA in the C-pole and of DMT1, Dcytb, FPN1, Heph, Hmox1, and ZIP14 mRNAs in the V-pole were markedly enhanced with increases occurring even in the C-pole. After iron feeding, the increased expression found in b/b rats persisted, except for Heph and ZIP14, which returned to normal levels. Thus in b/b rats depressed liver hepcidin production and activated intestinal Hif2α starting at the C-pole resulted in increasing expression of iron transport genes, including DMT1 G185R, in an attempt to compensate for the anemia in Belgrade rats.
Li C, etal., Am J Physiol Gastrointest Liver Physiol. 2015 Dec 1;309(11):G888-99. doi: 10.1152/ajpgi.00414.2014. Epub 2015 Oct 1.
The igf1 gene is alternatively spliced as IGF-IEa and IGF-IEc variants in humans. In fibrostenotic Crohn's disease, the fibrogenic cytokine TGF-beta1 induces IGF-IEa expression and IGF-I production in intestinal smooth muscle and results in muscle hyperplasia and collagen I production that contribut
e to stricture formation. Mechano-growth factor (MGF) derived from IGF-IEc induces skeletal and cardiac muscle hypertrophy following stress. We hypothesized that increased IGF-IEc expression and MGF production mediated smooth muscle hypertrophy also characteristic of fibrostenotic Crohn's disease. IGF-IEc transcripts and MGF protein were increased in muscle cells isolated from fibrostenotic intestine under regulation by endogenous TGF-beta1. Erk5 and MEF2C were phosphorylated in vivo in fibrostenotic muscle; both were phosphorylated and colocalized to nucleus in response to synthetic MGF in vitro. Smooth muscle-specific protein expression of alpha-smooth muscle actin, gamma-smooth muscle actin, and smoothelin was increased in affected intestine. Erk5 inhibition or MEF2C siRNA blocked smooth muscle-specific gene expression and hypertrophy induced by synthetic MGF. Conditioned media of cultured fibrostenotic muscle induced muscle hypertrophy that was inhibited by immunoneutralization of endogenous MGF or pro-IGF-IEc. The results indicate that TGF-beta1-dependent IGF-IEc expression and MGF production in patients with fibrostenotic Crohn's disease regulates smooth muscle cell hypertrophy a critical factor that contributes to intestinal stricture formation.
The G870A polymorphism in the exon 4/intron 4 boundary of CCND1 gene is thought to influence the generation of two mRNAs (cyclin D1a and cyclin D1b). The "A" allele codes for a truncated variant, cyclin D1b, which may have h
igher transforming activity. Herein, the tumor relevance of G870A polymorphism, the association between cyclin D1 variant expression and G870A genotype, and the oncogenic potential of cyclin D1 variants in HBV-related hepatocellular carcinoma (HCC) were examined. We found that there is no significant difference of G870A distribution among the HCC, chronic HBV (CHB) infection, cirrhotic CHB, and healthy control groups. Stratification analysis revealed that in younger patients (ages <= 50), cirrhotic CHB patients with AA genotype had an increased risk of developing HCC with odds ratio of 1.943 (95 % CI 1.022-3.694, p = 0.0411) as compared with AG/GG genotypes. The two variants were both transcripted from "A" and "G" alleles, and neither cyclin D1a nor D1b production was influenced by G870A genotype in HCC. The expression of both cyclins D1a and D1b decreased in HCC tissues (p = 0.003, p = 0.005), while increased in adjacent nontumor tissues as compared with normal liver tissues (p = 0.045, p = 0.034). Overexpression of cyclin D1a or D1b could promote the cell proliferation and cell-cycle progression in Huh-7 and LO2 cell lines. Collectively, our data suggest that G870A polymorphism has only very limited predictive value for HBV-related HCC. Both cyclins D1a and D1b could promote cell proliferation, which might contribute to the potential oncogenic role of cyclin D1 variants during the precancerous cirrhotic stage of hepatocarcinogenesis.
There is growing evidence that pancreatic stellate cells (PSCs) produce cytokines and take part in the regulation of inflammatory processes in the pancreas. IL-15 inhibits apoptosis of various cell populations. This study was performed to investigate whether PSCs produce IL-15 and thereby can affect
lymphocytes. Primary PSCs were isolated from the rat pancreas using density gradient centrifugation. mRNA expression of IL-15 was demonstrated by RT-PCR, and IL-15 protein was analyzed by immunoblotting. Lymphocytes obtained from rat mesenterial lymph nodes were cocultured with in vitro activated PSCs. Apoptosis has been quantified by the binding of annexin V-FITC with a flow cytometer. Proliferation was monitored using [3H]thymidine incorporation. PSCs express two splice variants of IL-15. The protein was detectable only in cell lysates but not in the cell culture supernatant. Cocultivation of lymphocytes with PSCs and IL-15 inhibited spontaneous lymphocyte apoptosis, and this effect was reduced by an anti-IL-15 antibody. Lymphocytes induced vice versa the proliferation and collagen production of PSCs. The inhibition of spontaneous lymphocyte apoptosis in cocultures with PSCs was at least partially mediated by cell-bound IL-15. This effect and the stimulation of PSCs by lymphocytes may lead to a circulus vitiosus, resulting in the persistence of inflammatory processes and the development of fibrosis during chronic pancreatitis.
Juskeviciute E, etal., Am J Physiol Gastrointest Liver Physiol. 2016 Nov 1;311(5):G794-G806. doi: 10.1152/ajpgi.00292.2016. Epub 2016 Sep 15.
Liver regeneration is a clinically significant tissue repair process that is suppressed by chronic alcohol intake through poorly understood mechanisms. Recently, microRNA-21 (miR-21) has been suggested to serve as a crucial microRNA (miRNA) regulator driving hepatocyte proliferation after partial he
patectomy (PHx) in mice. However, we reported recently that miR-21 is significantly upregulated in ethanol-fed rats 24 h after PHx, despite inhibition of cell proliferation, suggesting a more complex role for this miRNA. Here, we investigate how inhibition of miR-21 in vivo affects the early phase of liver regeneration in ethanol-fed rats. Chronically ethanol-fed rats and pair-fed control animals were treated with AM21, a mixed locked nucleic acid-DNA analog antisense to miR-21 that inhibited miR-21 in vivo to undetectable levels. Liver regeneration after PHx was followed by cell proliferation marker and gene expression analysis, miRNA profiling, and cell signaling pathway analysis. Although liver regeneration was not significantly impaired by AM21 in chow-fed rats, AM21 treatment in ethanol-fed animals completely restored regeneration and enhanced PHx-induced hepatocyte proliferation to levels comparable to those of untreated or chow-fed animals. In addition, a marked deposition of α-smooth muscle actin, a marker of stellate cell activation, which was evident in ethanol-treated animals after PHx, was effectively suppressed by AM21 treatment. Gene expression analysis further indicated that suppression of stellate cell-specific profibrogenic profiles and the Notch signaling contributed to AM21-mediated rescue from deficient hepatocyte proliferation in ethanol-fed animals. Our results indicate that the impact of miR-21 balances proproliferative effects with antiproliferative profibrogenic actions in regulating distinctive regenerative responses in normal vs. disease conditions.
Srinivasan P, etal., Am J Physiol Gastrointest Liver Physiol. 2016 May 15;310(10):G874-83. doi: 10.1152/ajpgi.00461.2015. Epub 2016 Mar 17.
Thiamin is essential for normal metabolism in pancreatic acinar cells (PAC) and is obtained from their microenvironment through specific plasma-membrane transporters, converted to thiamin pyrophosphate (TPP) in the cytoplasm, followed by uptake of TPP by mitochondria through the mitochondrial TPP (M
TPP) transporter (MTPPT; product of SLC25A19 gene). TPP is essential for normal mitochondrial function. We examined the effect of long-term/chronic exposure of PAC in vitro (pancreatic acinar 266-6 cells) and in vivo (wild-type or transgenic mice carrying the SLC25A19 promoter) of the cigarette smoke toxin, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), on the MTPP uptake process. Our in vitro and in vivo findings demonstrate that NNK negatively affects MTPP uptake and reduced expression of MTPPT protein, MTPPT mRNA, and heterogenous nuclear RNA, as well as SLC25A19 promoter activity. The effect of NNK on Slc25a19 transcription was neither mediated by changes in expression of transcriptional factor NFY-1 (known to drive SLC25A19 transcription), nor due to changes in methylation profile of the Slc25a19 promoter. Rather, it appears to be due to changes in histone modifications that involve significant decreases in histone H3K4-trimethylation and H3K9-acetylation (activation markers). The effect of NNK on MTPPT function is mediated through the nonneuronal alpha7-nicotinic acetylcholine receptor (alpha7-nAChR), as indicated by both in vitro (using the nAChR antagonist mecamylamine) and in vivo (using an alpha7-nAchR(-/-) mouse model) studies. These findings demonstrate that chronic exposure of PAC to NNK negatively impacts PAC MTPP uptake. This effect appears to be exerted at the level of Slc25a19 transcription, involve epigenetic mechanism(s), and is mediated through the alpha7-nAchR.
Sedgeman LR, etal., Am J Physiol Gastrointest Liver Physiol. 2018 Nov 1;315(5):G810-G823. doi: 10.1152/ajpgi.00238.2018. Epub 2018 Aug 30.
Colesevelam is a bile acid sequestrant approved to treat both hyperlipidemia and type 2 diabetes, but the mechanism for its glucose-lowering effects is not fully understood. The aim of this study was to investigate the role of hepatic microRNAs (miRNAs) as regulators of metabolic disease and to inve
stigate the link between the cholesterol and glucose-lowering effects of colesevelam. To quantify the impact of colesevelam treatment in rodent models of diabetes, metabolic studies were performed in Zucker diabetic fatty (ZDF) rats and db/db mice. Colesevelam treatments significantly decreased plasma glucose levels and increased glycolysis in the absence of changes to insulin levels in ZDF rats and db/db mice. High-throughput sequencing and real-time PCR were used to quantify hepatic miRNA and mRNA changes, and the cholesterol-sensitive miR-96/182/183 cluster was found to be significantly increased in livers from ZDF rats treated with colesevelam compared with vehicle controls. Inhibition of miR-182 in vivo attenuated colesevelam-mediated improvements to glycemic control in db/db mice. Hepatic expression of mediator complex subunit 1 (MED1), a nuclear receptor coactivator, was significantly decreased with colesevelam treatments in db/db mice, and MED1 was experimentally validated to be a direct target of miR-96/182/183 in humans and mice. In summary, these results support that colesevelam likely improves glycemic control through hepatic miR-182-5p, a mechanism that directly links cholesterol and glucose metabolism. NEW & NOTEWORTHY Colesevelam lowers systemic glucose levels in Zucker diabetic fatty rats and db/db mice and increases hepatic levels of the sterol response element binding protein 2-responsive microRNA cluster miR-96/182/183. Inhibition of miR-182 in vivo reverses the glucose-lowering effects of colesevelam in db/db mice. Mediator complex subunit 1 (MED1) is a novel, direct target of the miR-96/182/183 cluster in mice and humans.
Heller S, etal., Am J Physiol Gastrointest Liver Physiol. 2016 May 15;310(10):G844-54. doi: 10.1152/ajpgi.00407.2015. Epub 2016 Mar 11.
Intestinal inflammation has been recently characterized by the dysregulation of lipids as metabolic and energy sources, revealing a novel feature of its pathophysiology. Because intracellular lipids, stored in dynamic lipid droplets (LDs), provide energy for cellular needs, we investigated whether t
hey play a role in intestinal inflammation. In the inflamed intestine of mice, elevated LDs were found in colonic and infiltrating immune cells as shown by staining for the LD coat protein PLIN2 and for lipids with BODIPY. In colonic cells, TNF stimulated LD increases by receptor signaling rely on phosphatidylinositol 3-kinase activation. Downstream, TNF triggered a negative regulatory loop between LDs and the transcription factor FOXO3. This was shown in the colon of Foxo3-deficient mice, where elevation in PLIN2 and lipids were further facilitated by inflammation and were more prominent relative to wild-type, whereas, in colonic cells, inhibition of lipogenesis blocked the TNF-mediated loss of FOXO3. Furthermore, blockade of PGE2 synthesis abrogated TNF-stimulated increases in LDs and FOXO3 inactivation. We found in colonic tissue of Foxo3-deficient mice higher levels of cyclooxygenase-2, a mediator of prostaglandin E2 (PGE2) synthesis, supporting involvement of PGE2 in the LD-FOXO3 regulatory loop. Ultimately, TNF-stimulated lipogenesis leading to elevated LDs facilitated NF-kappaB-mediated increases in IL-8 protein, which is associated with the surface of LDs found in the lumina of the endoplasmic reticulum and Golgi apparatus. This novel immunometabolic mechanism of colonic inflammation involving elevated LDs could provide opportunities for new treatment options.
Mancinelli R, etal., Am J Physiol Gastrointest Liver Physiol. 2015 Dec 1;309(11):G865-73. doi: 10.1152/ajpgi.00015.2015. Epub 2015 Oct 8.
Liver transplantation and cholangiocarcinoma induce biliary dysfunction following ischemia reperfusion (IR). The function of the intrahepatic biliary tree is regulated by both autocrine and paracrine factors. The aim of the study was to demonstrate that IR-induced damage of cholangiocytes is associa
ted with altered expression of biliary angiogenic factors. Normal and bile duct ligation rats underwent 24-h sham or hepatic reperfusion after 30 min of transient occlusion of the hepatic artery (HAIR) or portal vein (PVIR) before collecting liver blocks and cholangiocyte RNA or protein. We evaluated liver histology, biliary apoptosis, proliferation and expression of VEGF-A/C, VEGFR-2/3, Ang-1/2, and Tie-1/2 in liver sections and isolated small and large cholangiocytes. Normal rat intrahepatic cholangiocyte cultures (NRICC) were maintained under standard conditions in normoxic or under a hypoxic atmosphere for 4 h and then transferred to normal conditions for selected times. Subsequently, we measured changes in biliary proliferation and apoptosis and the expression of VEGF-A/C and VEGFR-2/3. In vivo, HAIR (but not PVIR) induced damage of large bile ducts and decreased proliferation and secretin-stimulated cAMP levels. HAIR-induced damage of large bile ducts was associated with increased expression of VEGF-A/C, VEGFR-2/3, Ang-1/2, and Tie-1/2. In vitro, under hypoxic conditions, there was increased apoptosis and reduced proliferation of NRICC concomitant with enhanced expression of VEGF-A/C and VEGFR-2/3. The functional damage of large bile ducts by HAIR and hypoxia is associated with increased expression of angiogenic factors in small cholangiocytes, presumably due to a compensatory mechanism in response to biliary damage.
Wang A, etal., Am J Physiol Gastrointest Liver Physiol. 2015 Dec 1;309(11):G855-64. doi: 10.1152/ajpgi.00278.2015. Epub 2015 Oct 1.
The newest member of the Na(+)/H(+) exchanger (NHE) family, NHE8, is abundantly expressed at the apical membrane of the intestinal epithelia. We previously reported that mucin 2 expression was significantly decreased in the colon in NHE8(-/-) mice, suggesting that NHE8 is involved in intestinal muco
sal protection. In this study, we further evaluated the role of NHE8 in intestinal epithelial protection after dextran sodium sulfate (DSS) challenge. Compared with wild-type mice, NHE8(-/-) mice have increased bacterial adhesion and inflammation, especially in the distal colon. NHE8(-/-) mice are also susceptible to DSS treatment. Real-time PCR detected a remarkable increase in the expression of IL-1beta, IL-6, TNF-alpha, and IL-4 in DSS-treated NHE8(-/-) mice compared with DSS-treated wild-type littermates. Immunohistochemistry showed a disorganized epithelial layer in the colon of NHE8(-/-) mice. Periodic acid-Schiff staining showed a reduction in the number of mature goblet cells and the area of the goblet cell theca in NHE8(-/-) mice. Phyloxine/tartrazine staining revealed a decrease in functional Paneth cell population in the NHE8(-/-) small intestinal crypt. The expression of enteric defensins was also decreased in NHE8(-/-) mice. The reduced mucin production in goblet cells and antimicrobial peptides production in Paneth cells lead to disruption of the intestinal mucosa protection. Therefore, NHE8 may be involved in the establishment of intestinal mucosal integrity by regulating the functions of goblet and Paneth cells.
Strom TB, etal., FEBS Open Bio. 2014 Mar 19;4:321-7. doi: 10.1016/j.fob.2014.03.007. eCollection 2014.
More than 1700 mutations in the low density lipoprotein receptor (LDLR) gene have been found to cause familial hypercholesterolemia (FH). These are commonly divided into five classes based upon their effects on the structure and function of the LDLR. However, little is known about the mechanism by
which mutations in the transmembrane domain of the LDLR gene cause FH. We have studied how the transmembrane mutation G805R affects the function of the LDLR. Based upon Western blot analyses of transfected HepG2 cells, mutation G805R reduced the amounts of the 120 kDa precursor LDLR in the endoplasmic reticulum. This led to reduced amounts of the mature 160 kDa LDLR at the cell surface. However, significant amounts of a secreted 140 kDa G805R-LDLR ectodomain fragment was observed in the culture media. Treatment of the cells with the metalloproteinase inhibitor batimastat largely restored the amounts of the 120 and 160 kDa forms in cell lysates, and prevented secretion of the 140 kDa ectodomain fragment. Together, these data indicate that a metalloproteinase cleaved the ectodomain of the 120 kDa precursor G805R-LDLR in the endoplasmic reticulum. It was the presence of the polar Arg805 and not the lack of Gly805 which led to ectodomain cleavage. Arg805 also prevented gamma-secretase cleavage within the transmembrane domain. It is conceivable that introducing a charged residue within the hydrophobic membrane lipid bilayer, results in less efficient incorporation of the 120 kDa G805R-LDLR in the endoplasmic reticulum membrane and makes it a substrate for metalloproteinase cleavage.
Pelletier AM, etal., Am J Physiol Gastrointest Liver Physiol. 2010 Jun;298(6):G896-907. Epub 2010 Mar 25.
Hyperplasia of smooth muscle contributes to the thickening of the intestinal wall that is characteristic of inflammation, but the mechanisms of growth control are unknown. Nitric oxide (NO) from enteric neurons expressing neuronal NO synthase (nNOS) might normally inhibit intestinal smooth muscle ce
ll (ISMC) growth, and this was tested in vitro. In ISMC from the circular smooth muscle of the adult rat colon, chemical NO donors inhibited [(3)H]thymidine uptake in response to FCS, reducing this to baseline without toxicity. This effect was inhibited by the guanylyl cyclase inhibitor ODQ and potentiated by the phosphodiesterase-5 inhibitor zaprinast. Inhibition was mimicked by 8-bromo (8-Br)-cGMP, and ELISA measurements showed increased levels of cGMP but not cAMP in response to sodium nitroprusside. However, 8-Br-cAMP and cilostamide also showed inhibitory actions, suggesting an additional role for cAMP. Via a coculture model of ISMC and myenteric neurons, immunocytochemistry and image analysis showed that innervation reduced bromodeoxyuridine uptake by ISMC. Specific blockers of nNOS (7-NI, NAAN) significantly increased [(3)H]thymidine uptake in response to a standard stimulus, showing that nNOS activity normally inhibits ISMC growth. In vivo, nNOS axon number was reduced threefold by day 1 of trinitrobenzene sulfonic acid-induced rat colitis, preceding the hyperplasia of ISMC described earlier in this model. We conclude that NO can inhibit ISMC growth primarily via a cGMP-dependent mechanism. Functional evidence that NO derived from nNOS causes inhibition of ISMC growth in vitro predicts that the loss of nNOS expression in colitis contributes to ISMC hyperplasia in vivo.
Ajmo JM, etal., Am J Physiol Gastrointest Liver Physiol. 2008 Oct;295(4):G833-42. doi: 10.1152/ajpgi.90358.2008. Epub 2008 Aug 28.
Alcoholic fatty liver is associated with inhibition of sirtuin 1 (SIRT1) and AMP-activated kinase (AMPK), two critical signaling molecules regulating the pathways of hepatic lipid metabolism in animals. Resveratrol, a dietary polyphenol, has been identified as a potent activator for both SIRT1 and A
MPK. In the present study, we have carried out in vivo animal experiments that test the ability of resveratrol to reverse the inhibitory effects of chronic ethanol feeding on hepatic SIRT1-AMPK signaling system and to prevent the development of alcoholic liver steatosis. Resveratrol treatment increased SIRT1 expression levels and stimulated AMPK activity in livers of ethanol-fed mice. The resveratrol-mediated increase in activities of SIRT1 and AMPK was associated with suppression of sterol regulatory element binding protein 1 (SREBP-1) and activation of peroxisome proliferator-activated receptor gamma coactivator alpha (PGC-1alpha). In parallel, in ethanol-fed mice, resveratrol administration markedly increased circulating adiponectin levels and enhanced mRNA expression of hepatic adiponectin receptors (AdipoR1/R2). In conclusion, resveratrol treatment led to reduced lipid synthesis and increased rates of fatty acid oxidation and prevented alcoholic liver steatosis. The protective action of resveratrol is in whole or in part mediated through the upregulation of a SIRT1-AMPK signaling system in the livers of ethanol-fed mice. Our study suggests that resveratrol may serve as a promising agent for preventing or treating human alcoholic fatty liver disease.
An early event that occurs in response to alcohol consumption is mitochondrial dysfunction, which is evident in changes to the mitochondrial proteome, respiration defects, and mitochondrial DNA (mtDNA) damage. S-adenosylmethionine (SAM) has emerged as a potential therapeutic for treating alcoholic l
iver disease through mechanisms that appear to involve decreases in oxidative stress and proinflammatory cytokine production as well as the alleviation of steatosis. Because mitochondria are a source of reactive oxygen/nitrogen species and a target for oxidative damage, we tested the hypothesis that SAM treatment during alcohol exposure preserves organelle function. Mitochondria were isolated from livers of rats fed control and ethanol diets with and without SAM for 5 wk. Alcohol feeding caused a significant decrease in state 3 respiration and the respiratory control ratio, whereas SAM administration prevented these alcohol-mediated defects and preserved hepatic SAM levels. SAM treatment prevented alcohol-associated increases in mitochondrial superoxide production, mtDNA damage, and inducible nitric oxide synthase induction, without a significant lessening of steatosis. Accompanying these indexes of oxidant damage, SAM prevented alcohol-mediated losses in cytochrome c oxidase subunits as shown using blue native PAGE proteomics and immunoblot analysis, which resulted in partial preservation of complex IV activity. SAM treatment attenuated the upregulation of the mitochondrial stress chaperone prohibitin. Although SAM supplementation did not alleviate steatosis by itself, SAM prevented several key alcohol-mediated defects to the mitochondria genome and proteome that contribute to the bioenergetic defect in the liver after alcohol consumption. These findings reveal new molecular targets through which SAM may work to alleviate one critical component of alcohol-induced liver injury: mitochondria dysfunction.
Nefedova VV, etal., Arch Biochem Biophys. 2013 Oct 1;538(1):16-24. doi: 10.1016/j.abb.2013.07.028. Epub 2013 Aug 12.
Some properties of G84R and L99M mutants of HspB1 associated with peripheral distal neuropathies were investigated. Homooligomers formed by these mutants are larger than those of the wild type HspB1. Large oligomers of ... (more)
n style='font-weight:700;'>G84R and L99M mutants have compromised stability and tend to dissociate at low protein concentration. G84R and L99M mutations promote phosphorylation-dependent dissociation of HspB1 oligomers without affecting kinetics of HspB1 phosphorylation by MAPKAP2 kinase. Both mutants weakly interact with HspB6 forming small heterooligomers and being unable to form large heterooligomers characteristic for the wild type HspB1. G84R and L99M mutants possess lower chaperone-like activity than the wild type HspB1 with several model substrates. We suggest that G84R mutation affects mobility and accessibility of the N-terminal domain thus modifying interdimer contacts in HspB1 oligomers. The L99M mutation is located within the hydrophobic core of the alpha-crystallin domain close to the key R140 residue, and could affect the dimer stability.
The 5-HT(1B) receptor has been implicated in several psychopathologies, including pathological aggression, alcoholism and suicide. To test these and related potential genetic relationships in a single population, the human 5-HT(1B) receptor (h5-HTR(1B)) genotype for the G8
'>G861C polymorphism was determined in 394 psychiatric patients and 96 healthy volunteers. Structured clinical interviews generated DSM III-R diagnoses. No significant association of the genotype or allele frequencies of the h5-HTR(1B) G861C locus was observed with diagnoses of alcoholism, bipolar disorder, schizophrenia or a history of a suicide attempt. Exploratory analyses indicated an association of the genotype and allele frequencies of the h5-HTR(1B) G861C locus with a history of substance abuse disorder (chi(2) = 9.51, df = 2, p = 0.009; chi(2) = 7.31, df = 1, p = 0.007, respectively) and with a diagnosis of a major depressive episode (chi(2) = 6.83, df = 2, p = 0.033; chi(2) = 5.81, df = 1, p = 0.016, respectively). Significant gene dose effects on the risk for substance abuse disorder and a major depressive episode were observed with the 861C allele (Armitage linearity tendency test: chi(2) = 7.20, df = 1, p = 0.008; chi(2) = 6.80, df = 1, p = 0.009, respectively). Substance abuse disorder and major depression appear to be associated with the h5-HTR(1B) G861C locus in the patient population, but other psychopathologies such as bipolar disorder, schizophrenia, alcoholism, and suicide attempts were not found to be associated with this polymorphism. This preliminary result will need replication, given the limitations of association studies.
Roesly HB, etal., Am J Physiol Gastrointest Liver Physiol. 2012 Apr 15;302(8):G864-72. doi: 10.1152/ajpgi.00340.2011. Epub 2012 Feb 2.
Beclin-1 has a central role in the regulation of autophagy. Barrett's esophagus (BE) is associated with a significantly increased risk for the development of esophageal adenocarcinoma (EAC). In the current study, we evaluated the role of Beclin-1 and autophagy in the EAC. Biopsies obtained from pati
ents with BE and EAC, tissues from a rat model of BE and EAC, and esophageal cell lines were evaluated for the expression of Beclin-1 by immunohistochemistry, immunoblotting, or RT-PCR. Since reflux of bile acids is important in EAC, we also evaluated the effect of exposure to deoxycholic acid (DCA) on autophagy and Beclin-1 expression. Beclin-1 expression was high in squamous epithelium and nondysplastic BE, whereas its expression was low in dysplastic BE and EAC. The same pattern of expression was observed in rat tissues and in esophageal cell lines. Normal esophageal epithelium and HET-1A cells (derived from normal squamous epithelium) show high levels of Beclin-1, but lower levels of Beclin-1 were found in BE and EAC cell lines (CP-A, CP-C, and OE33). Acute exposure to DCA led to increased Beclin-1 expression and increased autophagy as evaluated by electron microscopy and counting percentage of GFP-LC3-positive BE cells with punctate pattern. In contrast, chronic exposure to DCA did not result in the alteration of Beclin-1 levels or autophagy. In summary, these data suggest that autophagy is initially activated in response to bile acids, but chronic exposure to bile acids leads to decreased Beclin-1 expression and autophagy resistance.
Beebe-Dimmer JL, etal., Cancer Epidemiol Biomarkers Prev. 2015 Sep;24(9):1366-72. doi: 10.1158/1055-9965.EPI-15-0247. Epub 2015 Jun 24.
BACKGROUND: A rare nonconservative substitution (G84E) in the HOXB13 gene has been shown to be associated with risk of prostate cancer. DNA samples from male patients included in the Mayo Clinic Biobank (MCB) were genotyped
to determine the frequency of the G84E mutation and its association with various cancers. METHODS: Subjects were genotyped using a custom TaqMan (Applied Biosystems) assay for G84E (rs138213197). In addition to donating a blood specimen, all MCB participants completed a baseline questionnaire to collect information on medical history and family history of cancer. RESULTS: Forty-nine of 9,012 male patients were carriers of G84E (0.5%). Thirty-one percent (n = 2,595) of participants had been diagnosed with cancer, including 51.1% of G84E carriers compared with just 30.6% of noncarriers (P = 0.004). G84E was most frequently observed among men with prostate cancer compared with men without cancer (P < 0.0001). However, the mutation was also more commonly observed in men with bladder cancer (P = 0.06) and leukemia (P = 0.01). G84E carriers were more likely to have a positive family history of prostate cancer in a first-degree relative compared to noncarriers (36.2% vs. 16.0%, P = 0.0003). CONCLUSIONS: Our study confirms the association between the HOXB13 G84E variant and prostate cancer and suggests a novel association between G84E and leukemia and a suggestive association with bladder cancer. Future investigation is warranted to confirm these associations in order to improve our understanding of the role of germline HOXB13 mutations in human cancer. IMPACT: The associations between HOXB13 and prostate, leukemia, and bladder suggest that this gene is important in carcinogenesis.
Liu S, etal., Sci Rep. 2015 Sep 4;5:13598. doi: 10.1038/srep13598.
The association between the G894T polymorphism (Glu298Asp) of nitric oxide synthase 3 (NOS3) and risk of Alzheimer's disease (AD) was explored by performing a meta-analysis of case-control studies. Bibliographical searches w
ere conducted in the MEDLINE, EMBASE, and China National Knowledge Infrastructure (CNKI) databases without any language limitations. Two investigators independently assessed abstracts for relevant studies, and reviewed all eligible studies. We adopted regrouping in accordance with the most probably appropriate genetic model. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of this association. We performed a meta-analysis including 21 published articles with 23 case-control studies (5,670 cases and 5,046 controls). In the analyses, we found significant association between G894T polymorphism and AD risk under a complete overdominant model (GG + TT vs. GT) (OR = 1.18; 95%CI, 1.04-1.35; P = 0.010). When stratified by time of AD onset, we found the association between this polymorphism and AD susceptibility to be more substantial among late onset patients than among early onset patients (OR for late vs. early onset: 1.33 vs. 1.02, P interaction = 0.049). The meta-analysis showed that the polymorphism G894T of NOS3 was associated with risk of AD.
Retinal vein occlusion (RVO) is associated with hyperhomocysteinaemia and the antiphospholipid syndrome-disorders known to contribute to both arterial and venous thrombosis. In both of these conditions and RVO, platelet activation occurs. Aspirin, not warfarin, is the most effective antithrombotic a
gent in RVO and, taken together, these observations suggest an important role for platelets in this common ocular thrombotic condition. Platelet glycoprotein Ia/IIa (GpIa/IIa) is an adhesion molecule mediating platelet-collagen interactions and is key to the initiation of thrombosis. Recently, the cellular density of this molecule was shown to be determined by two silent, linked polymorphisms (C807T/G873A) within the GpIa/IIa gene. There is evidence that some of the resulting genotypes are associated with thrombo-embolic disease. This study therefore aimed to establish the prevalence of the GpIa/IIa polymorphisms and the three commonest hereditary thrombophilic disorders (prothrombin gene G20210A (PT) mutation, Factor V Leiden (FVL), and the thermolabile methylene tetrahydrofolate reductase C677T (MTHFR) mutation) in patients with RVO and normal controls. The GpIa/IIa polymorphisms and thrombophilic abnormalities were all identified using the polymerase chain reaction.Our results show that the frequency of the GpIa/IIa polymorphisms was similar in our normal control population to previously published series. Patients with RVO, however, had only a 10% (4/40) frequency of the lowest risk subtype (CC/GG) compared to 37.5% (15/40) in the control group-P 0.0039. The incidence of the PT, FVL, and MTHFR thrombophilic mutations was not different between the two groups, but interestingly none of the 7/40 RVO cases with a PT, FVL, or MTHFR mutation had the low-risk GpIa/IIa genotype while all but one of the controls did-P<0.05. Thus, 17.5% of RVO patients harboured more than one prothrombotic abnormality. The principal difference between the RVO and control group was the very high incidence of the intermediate-risk GpIa/IIa subtype (CT/GA)-82.5 vs 50%, P&<0.05. These results suggest a major role for GpIa/IIa polymorphisms in the pathogenesis of RVO.
Diler SB and Oden A, Genetika. 2016 Feb;52(2):249-54.
In previously conducted some studies it has been revealed that nitric oxide (NO) and nitric oxide synthase (NOS) system play a significant role in carcinogenesis. Nitric oxide (NO) is regulated by endothelial nitric oxide synthase (eNOS) enzyme which is one of the isoenzymes of NO synthase (NOS). I
n this study we have tried to come to a conclusion about whether eNOS gene T -786C, G894T and Intron 4 VNTR (4a/b) polymorphisms might be considered as a risk factor causing prostate cancer (PCa) or not. A total of 200 subjects were included in this research. 84 patients with PCa (mean age 70.0 +/- 6.4) and 116 healthy controls (mean age 69.9 +/- 7.5) were recruited in this case-control study. Genomic DNA was extracted using the QIAamp DNA Blood Mini Kit (QIAGEN GmbH, Maryland, USA), according to the manufacturer's guidelines. The T-786C, G894T and Intron 4 VNTR (4a/b) polymorphisms were amplified using polymerase chain reation (PCR), detected by restriction fragment length polymorphism (RFLP). For T -786C polymorphism CC genotype [odds ratio (OR): 0.34, 95% confidence interval (CI): 0.15-0.78, P = 0.009)] and allele frequency (OR: 0.631, CI: 0.421-0.946, P = 0.026) is significant for control. In patients with PCa eNOS G894T polymorphism, both GT (OR: 0.069, CI: 0.027-0.174; P = 0.0001) and TT (OR: 0.040, CI: 0.013-0.123; P = = 0.0001) genotype distribution, and also T allele frequency (OR: 0.237, CI: 0.155-0.362, P = 0.0001) were considered significant statistically. While genotype distribution for the other polymorphism eNOS, intron 4 VNTR (4a/b), is insignificant statistically, "a" allele frequency was found out to be significant (OR: 2.223, CI: 1.311-3.769, P = 0.003). In this study we indicated that genotype and allele frequencies of eNOS T -786C and G894T polymorphisms are statistically significant in patients with PCa. eNOS T -786C and G894T polymorphisms may be associated with PCa susceptibility in the Turkish population. In contrast, intron 4 VNTR (4a/b) polymorphism may not be related to PCa susceptibility in these patients.
Mochizuki K, etal., Am J Physiol Gastrointest Liver Physiol. 2007 Mar;292(3):G818-28. doi: 10.1152/ajpgi.00415.2006. Epub 2006 Nov 2.
The aim of this study was to determine the role of N-linked glycosylation in protein stability, intracellular trafficking, and bile acid transport activity of the bile salt export pump [Bsep (ATP-binding cassette B11)]. Rat Bsep was fused with yellow fluorescent protein, and the following mutants, i
n which Asn residues of putative glycosylation sites (Asn(109), Asn(116), Asn(122), and Asn(125)) were sequentially replaced with Gln, were constructed by site-directed mutagenesis: single N109Q, double N109Q + N116Q, triple N109Q + N116Q + N122Q, and quadruple N109Q + N116Q + N122Q + N125Q. Immunoblot and glycosidase cleavage analysis demonstrated that each site was glycosylated. Removal of glycans decreased taurocholate transport activity as determined in polarized MDCK II cells. This decrease resulted from rapid decay of the mutant Bsep protein; biochemical half-lives were 3.76, 3.65, 3.24, 1.35, and 0.52 h in wild-type, single-mutant, double-mutant, triple-mutant, and quadruple-mutant cells, respectively. Wild-type and single- and double-mutant proteins were distributed exclusively along the apical membranes, whereas triple- and quadruple-mutant proteins remained intracellular. MG-132 but not bafilomycin A(1) extended the half-life, suggesting a role for the proteasome in Bsep degradation. To determine whether a specific glycosylation site or the number of glycans was critical for protein stability, we studied the protein expression of combinations of N-glycan-deficient mutants and observed that Bsep with one glycan was considerably unstable compared with Bsep harboring two or more glycans. In conclusion, at least two N-linked glycans are required for Bsep protein stability, intracellular trafficking, and function in the apical membrane.
