Association of Interleukin-1 gene polymorphisms with central obesity and metabolic syndrome in a coronary heart disease population

The objective of this study was to determine whether single nucleotide polymorphisms (SNPs) in the Interleukin-1 (IL-1) gene family are associated with central obesity and metabolic syndrome in a coronary heart disease population. The IL-1α C-889T (rs1800587) and IL-1β +3954 (rs1143634) SNPs were studied in a Western Australian coronary heart disease (CHD) population (N = 556). Subjects who were TT homozygous at either SNP had larger waist circumference (IL-1α: 1.8 cm greater, P = 0.04; IL-1β: 4 cm greater, P = 0.0004) compared with major allele homozygotes. Individuals with two copies of the IL-1α:IL-1β T:T haplotype had greater waist circumference (4.7 cm greater, P = 0.0001) compared to other haplotypes. There was a significant interaction between the IL-1β SNP and BMI level on waist circumference (P = 0.01). When the cohort was stratified by median BMI, TT carriers for IL-1β with above median BMI had greater waist circumference (6.1 cm greater, P = 0.007) compared to baseline carriers, whilst no significant association was seen in the below median group. Similarly, when the cohort was stratified by median fibrinogen level (IL-1α interaction P = 0.01; IL-1β interaction P = 0.04), TT carriers for both SNPs in the above median fibrinogen group had greater waist circumference (IL-1α 2.7 cm greater, P = 0.007; IL-1β 3.3 cm greater, P = 0.003) compared with major allele homozygotes. This association was not seen in the below median group. Also, we found a trend of increased metabolic syndrome for IL-1β TT homozygotes (P = 0.07). In conclusion, our findings suggest that in a CHD population IL-1 gene polymorphisms may be involved in increased central obesity, and the genetic influences are more evident among patients who have a higher level of obesity or inflammatory markers.     

−509C>T polymorphism in the TGF-β1 gene promoter,impact on the hepatocellular carcinoma risk in Chinese patients with chronic hepatitis B virus infection

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The risk for developing HCC increases with severity of inflammation and fibrosis. Transforming growth factor-β1 (TGF-β1) is most frequently upregulated in tumor cells. The most studied −509C>T polymorphism of TGF-β1 gene has been associated with colorectal, gynecologic, and lung cancers. To assess whether this polymorphism in TGF-β1 gene is associated with susceptibility to and/or clinicopathologic characteristics of HBV-related HCC, a total of 575 patients with chronic HBV infection and 299 healthy volunteers with no evidence of recent or remote HBV infection were prospectively enrolled. The patients were divided into two groups: those without (n = 196) and those with HCC (n = 379). These 379 HCC patients with chronic HBV infection were designated as cases, the remaining 196 patients without HCC and 299 healthy volunteers served as disease and healthy controls, respectively. −509C>T polymorphism in the TGF-β1 gene promoter was studied using restriction fragment-length polymorphism. In addition, tumor tissues of liver (n = 60) were obtained from the studied HCC patients for measurement of TGF-β1 mRNA expression levels. We also assessed the plasma TGF-β1 levels of HBV patients without (n = 94) or with HCC (n = 136) and healthy subjects (n = 120). In our study group, the risk of HCC in Chinese patients with HBV infection was significantly lower with the TT genotypes than in those with the CC genotypes at position −509 of TGF-β1 gene (P = 0.01). In addition, in the case group, patients with the CC genotype had a statistically significant higher median plasma TGF-β1 or liver tumor tissue TGF-β1 mRNA level compared with the individuals with the TT genotype. However, in a subsequent analysis of the association between this polymorphism and clinicopathological characteristics including tumor number, size, grade, stage, and invasiveness, there was no significant difference in both the distribution of genotype or allelic frequency within HCC patients, indicating that −509C>T exchange in TGF-β1 gene may play an important role in the occurrence, not the progression of HBV-related HCC through influencing plasma concentrations of TGF-β1 or TGF-β1 mRNA expression of liver tumor tissue.     

Downregulation of Apoptosis and Modulation of TGF-β1 by Sodium Selenate Prevents Streptozotocin-Induced Diabetic Rat Renal Impairment

To investigate whether sodium selenate treatment would impact on the onset of diabetic nephropathy, we examined blood glucose, serum biochemical components, and interrelationship between oxidative stress, TGF-β1, and apoptosis in streptozotocin (STZ) induced diabetic rats. Sixty male Wistar rats were divided into six groups. Group I (n = 10), normal control; Group II (n = 10), diabetic control; Group III (n = 10), sodium selenate (16 μmoles/kg) + diabetic; Group IV (n = 10), sodium selenate (32 μmoles/kg) + diabetic; Group V (n = 10), sodium selenate (16 μmoles/kg) control; and Group VI (n = 10), sodium selenate (32 μmoles/kg) control. Sodium selenate was administered via orogastric route for 10 weeks. In the diabetic group, diabetes was induced by single intraperitoneal injection of STZ (50 mg/kg). The levels of blood glucose were estimated and total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, creatinine, urea, and albumin were detected in serum. Antioxidant status was examined by measuring the superoxide dismutase (SOD), catalase, glutathione, and lipid peroxidation in kidney tissues. Histopathological studies were performed in the kidney tissue sections. The expression of TGF-β1 was estimated by the immunohistochemical analysis in kidneys. Apoptotic study in kidney was performed using the TdT-mediated dUTP nick end labeling technique. It was observed that blood glucose, serum, total cholesterol, HDL cholesterol, triglycerides, creatinine, urea, and albumin were significantly higher in diabetic control groups. Diabetic + sodium selenate (16 and 32 μmoles/kg) significantly reduced blood glucose, serum, total cholesterol, HDL cholesterol, triglycerides, creatinine, urea, and albumin levels. Selenium-treated groups significantly increased antioxidant enzyme activities (SOD, catalase, and glutathione) in kidneys of diabetic rats. All enzyme activities of selenium control groups did not differ compared with the normal control. Sodium selenate reduces significantly lipid peroxidation in diabetic rats. Cellular architecture of the diabetic rats was altered whereas sodium selenate administration rectifies the degenerative changes of the kidney. Profound immunopositivity of TGF-β1 was observed in the glomerular and tubulointerstitial cells of diabetic rat kidney. Immunopositivity of TGF-β1 was significantly reduced in both low and high dose of sodium-selenate-treated rats (P < 0.05, P < 0.01). High numbers of apoptotic cells were observed in diabetic rats whereas sodium selenate in both doses significantly reduces the incidence of apoptosis (P < 0.05, P < 0.01). We conclude herein that sodium selenate has the potential to play a significant role in limiting the renal impairment by altering the apoptosis and TGF-β1 in experimental diabetic rats.     

Expression of connective tissue growth factor and interleukin-11 in intratumoral tissue is associated with poor survival after curative resection of hepatocellular carcinoma

In the present study, we evaluated the prognostic value of intratumoral and peritumoral expression of connective tissue growth factor (CTGF), transforming growth factor-beta 1 (TGF-β1), and interleukin-11 (IL-11) in patients with hepatocellular carcinoma (HCC) after curative resection. Expression of CTGF, TGF-β1, and IL-11 was assessed by immunohistochemical staining of tissue microarrays containing paired tumor and peritumoral liver tissue from 290 patients who had undergone hepatectomy for histologically proven HCC. The prognostic value of these and other clinicopathologic factors were evaluated. The median follow-up time was 54.3 months (range, 4.3–118.3 months). High intratumoral CTGF expression was associated with vascular invasion (P = 0.015), intratumoral IL-11 expression correlated with higher tumor node metastasis (TNM) stage (P = 0.009), and peritumoral CTGF overexpression correlated with lack of tumor encapsulation (P = 0.031). Correlation analysis of these proteins revealed that intratumoral CTGF and IL-11 correlated with high intratumoral TGF-β1 expression (r = 0.325, P < 0.001; and r = 0.273, P < 0.001, respectively). TNM stage (P < 0.001), high intratumoral CTGF levels (P = 0.010), and intratumoral IL-11 expression (P = 0.015) were independent prognostic factors for progression-free survival (PFS). Vascular invasion (P = 0.032), TNM stage (P < 0.001), high intratumoral CTGF levels (P = 0.036), and intratumoral IL-11 expression (P = 0.013) were independent prognostic factors for overall survival (OS). High intratumoral CTGF and intratumoral IL-11 expression were associated with PFS and OS after hepatectomy, and the combination of intratumoral CTGF with IL-11 may be predictive of survival.     

Cytokine gene polymorphism and asthma susceptibility, progress and control level

Asthma is a multifactor inflammatory disorder, and its management requires understanding of its various pathogenesis and control mechanisms. Cytokines and other inflammatory mediators are important factors in asthma pathophysiology. In this study, we evaluated the role of cytokine polymorphisms in the asthma susceptibility, progress, control, and lung functions. IL-4-C590T polymorphism by PCR-RFLP method, IFN-γ T+874A, TNF-α-A308G, IL-6 G−174C and TGF-β T+869C variants by ARMS-PCR method and IgE serum level by ELISA technique were determined in 81 asthmatic patients and 124 normal subjects. Asthma diagnosis, treatment and control levels were considered using standard schemes and criteria. TNF-α−308GA genotype was more frequent in asthmatics (P = 0.025, OR 3.352), and polymorphisms between different asthma control levels (P > 0.05) were not different. IFN-γ+874AT genotype had a positive correlation with the familial history of asthma (P = 0.034, OR 2.688). IL-6−174C allele (P = 0.045), TNF-α−308GG genotype (P = 0.002) and TNF-α−308G allele (P = 0.004) showed reduced values, and TNF-α−308GA genotype (P = 0.002) increased FEF25-75 value in asthmatics. IFN-γ+874AA genotype caused a decrease in FVC factor (P = 0.045). This study showed that TNF-α−308GA is a risk factor for asthma, but cytokine gene variants do not affect asthma control and IgE serum levels. Variants producing lower levels of IL-6, TNF-α and IFN-γ are associated with reduced pulmonary capacities. To achieve an appropriate schema for asthma management, further studies with consideration of different aspects in a larger group of patients would be more elucidative.     

Effects of remifentanyl and fentanyl on LPS-induced cytokine release in human whole blood in vitro

Aim The present study sought insight into the effects of remifentanyl and fentanyl on LPS-induced release of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and IL-10 in human whole blood. Methods Whole blood was incubated in the presence and absence of remifentanyl and fentanyl. Effects of remifentanyl and fentanyl on spontaneous and endotoxin (lipopolysaccharide; 100 ng ml⁻¹)-stimulated cytokine release were studied in whole blood from volunteers (n = 10) cultured for 6 h. Results IL-6, TNF-α and IL-10 concentrations in groups added with LPS were significantly higher than those in control group (P < 0.01). IL-6, TNF-α and IL-10 concentrations in activation groups treated with remifentanyl or fentanyl were significantly lower than those in LPS treated group (P < 0.05). There were no significant differences on IL-6,TNF-α and IL-10 concentrations in drug-alone groups compared with control group (P > 0.05). Conclusion Remifentanyl or fentanyl alone has no effects on IL-6, TNF-α and IL-10 production, but could attenuate LPS-induced IL-6,TNF-α and IL-10 production in human whole blood. Remifentanyl and fentanyl could inhibit the expressions of IL-6, TNF-α and IL-10 induced by LPS.     

Heparan sulfate expression is affected by inflammatory stimuli in primary human endothelial cells

In diabetes the endothelium is either chronically or transiently exposed to hyperglycemic conditions. In addition, endothelial dysfunction in diabetes is related to changes in the inflammatory response and the turnover of extracellular matrix. This study was undertaken to study the effects of inflammatory stimuli on one particular matrix component, the heparan sulfate (HS) proteoglycans (PGs) synthesized by primary human umbilical cord vein endothelial cells (HUVEC). Such cells were cultured in vitro in 5 mM and 25 mM glucose. The latter concentration was used to mimic hyperglycemic conditions in short-term experiments. HUVEC were also cultured in the presence of the inflammatory agents tumor necrosis factor α (TNF-α), interleukin 1α (IL-1α), interleukin 1β (IL-1β) and transforming growth factor β (TGF-β). The cells were labeled with ³⁵S-sulfate and ³⁵S-PGs were recovered for further analyses. The major part of the ³⁵S-PGs was secreted to the medium, irrespective of type of stimuli. Secreted ³⁵S-PGs were therefore isolated and subjected to further analyses. TNF-α and IL-1α slightly increased the release of ³⁵S-PGs to the culture medium, whereas IL-1β treatment gave a significant increase. The different treatments neither changed the ratio of ³⁵S-HS and ³⁵S-chondroitin sulfate (CS) nor the macromolecular properties of the ³⁵S-PGs. However, the ³⁵S-HS chains were slightly increased in size after TNF-α treatment, and slightly decreased after TGF-β treatment, but not affected by the other treatments. Compositional analysis of labeled disaccharides showed changes in the amount of 6-O-sulfated glucosamine residues after treatment with TNF-α, IL-1α and IL-1β. Western immunoblotting showed that major HSPGs recovered from these cells were collagen XVIII, perlecan and agrin, and that secretion of these distinct PGs was increased after IL-1β stimulation. Hence, short term inflammatory stimuli increased the release of HSPGs in HUVEC and affected both the size and sulfation pattern of HS, depending on type of stimuli.     

Regulation of melanin synthesis by the TGF-β family in B16 melanoma cells

Effects of representative members of the transforming growth factor-β (TGF-β) family, TGF-β1, activin A and BMP-2, on melanin content and expression of pigment-producing enzymes were examined in B16 melanoma cells. Treatment with TGF-β1 or activin A but not with BMP-2 significantly decreased melanin content and expression of Tyrosinase and Tyrp-1, suggesting an inhibitory effect of TGF-β1 and activin A on melanin synthesis. TGF-β1 completely inhibited melanin synthesis induced by α-melanin stimulating hormone (α-MSH), whereas activin A only slightly did. As compared with parental B16 cells, the inhibitory effects of TGF-β1 and activin A on melanin content were relative smaller in B16 F10 cells, a subline of B16 cells that contain more pigment. The present study indicates that in addition to TGF-β, activin negatively regulates melanogenesis in the absence of α-MSH, but that the activity in the presence of α-MSH was slightly different between TGF-β and activin.     

Transforming growth factor β 869C/T and interleukin 6 -174G/C polymorphisms relate to the severity and progression of bone-erosive damage detected by ultrasound in rheumatoid arthritis

Introduction  

Single nucleotide polymorphisms (SNPs) of transforming growth factor β (TGF-β) and IL-6 genes (respectively, 869C/T and -174G/C) have been associated with radiographic severity of bone-erosive damage in patients with rheumatoid arthritis (RA). Musculoskeletal ultrasound (US) is more sensitive than radiography in detecting bone erosion. We analyzed the association between TGF-β 869C/T and IL-6 -174G/C SNPs and bone-erosive damage, evaluated by US, in a cohort of patients with severely active RA.     

IL-1β (−511T/C) gene polymorphism not IL-1β (+3953T/C) and LT-α (+252A/G) gene variants confers susceptibility to visceral leishmaniasis

Lymphotoxin-α (LT-α) and interleukin-1beta (IL-1β) are proinflammatory cytokines playing important roles in immunity against Leishmania infection and the outcome of the disease. As cytokine productions are under the genetic control, this study tried to find any probable relationship between these cytokine gene polymorphisms and the susceptibility to visceral leishmaniasis in Iranian pediatric patients. Ninety-five pediatric patients involved with visceral leishmaniasis and 128 non-relative healthy people, from the same area as the patients, were genotyped for LT-α (+252A/G) and IL-1β (+3953T/C and −511T/C) gene polymorphisms using polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP). There was not found any significant differences in allele and genotype frequencies of LT-α (+252A/G) and IL-1β (+3953) among the study groups. However, the frequency of IL-1β −511TT genotype was higher in the controls (P = 0.0004) while the frequency of IL-1β −511CC genotype and C allele were higher in the patients (P = 0.008 and P = 0.00006, respectively). Furthermore, IL-1β CC (−511/+3953) haplotype was more frequent in VL patients compared with the controls (P = 0.0002) and the distribution of TT haplotype was higher in the controls compared with the patients (P = 0.003). In conclusion, based on the results, IL-1β −511C allele, CC genotype and CC (−511/+3953) haplotype could be considered as the susceptibility factors for visceral leishmaniasis while IL-1β −511TT genotype, T allele and TT haplotype (−511/+3953) might be counted as the influential factors for resistance to the disease.     

Haplotypes of IL-10 promoter variants are associated with susceptibility to severe malarial anemia and functional changes in IL-10 production

Plasmodium falciparum malaria is one of the leading global causes of morbidity and mortality with African children bearing the highest disease burden. Among the various severe disease sequelae common to falciparum malaria, severe malarial anemia (SMA) in pediatric populations accounts for the greatest degree of mortality. Although the patho-physiological basis of SMA remains unclear, dysregulation in inflammatory mediators, such as interleukin (IL)-10, appear to play an important role in determining disease outcomes. Since polymorphic variability in innate immune response genes conditions susceptibility to malaria, the relationship between common IL-10 promoter variants (−1,082A/G, −819T/C, and −592A/C), SMA (Hb < 6.0 g/dL), and circulating inflammatory mediator levels (i.e., IL-10, TNF-α, IL-6 and IL-12) were investigated in parasitemic Kenyan children (n = 375) in a holoendemic P. falciparum transmission area. Multivariate logistic regression analyses demonstrated that the −1,082G/−819C/−592C (GCC) haplotype was associated with protection against SMA (OR; 0.68, 95% CI, 0.43–1.05; P = 0.044) and increased IL-10 production (P = 0.029). Although none of the other haplotypes were significantly associated with susceptibility to SMA, individuals with the −1,082A/−819T/−592A (ATA) haplotype had an increased risk of SMA and reduced circulating IL-10 levels (P = 0.042). Additional results revealed that the IL-10:TNF-α ratio was higher in the GCC group (P = 0.024) and lower in individuals with the ATA haplotype (P = 0.034), while the IL-10:IL-12 ratio was higher in ATA haplotype (P = 0.006). Results presented here demonstrate that common IL-10 promoter haplotypes condition susceptibility to SMA and functional changes in circulating IL-10, TNF-α, and IL-12 levels in children with falciparum malaria. The study was approved by the ethical and scientific review committees at the Kenya Medical Research Institute and the institutional review board at the University of Pittsburgh.     

Lysozyme transgenic goats’ milk positively impacts intestinal cytokine expression and morphology

In addition to its well-recognized antimicrobial properties, lysozyme can also modulate the inflammatory response. This ability may be particularly important in the gastrointestinal tract where inappropriate inflammatory reactions can damage the intestinal epithelium, leading to significant health problems. The consumption of milk from transgenic goats producing human lysozyme (hLZ) in their milk therefore has the potential to positively impact intestinal health. In order to investigate the effect of hLZ-containing milk on the inflammatory response, young pigs were fed pasteurized milk from hLZ or non-transgenic control goats and quantitative real-time PCR was performed to assess local expression of TNF-α, IL-8, and TGF-β1 in the small intestine. Histological changes were also investigated, specifically looking at villi width, length, crypt depth, and lamina propria thickness along with cell counts for intraepithelial lymphocytes and goblet cells. Significantly higher expression of anti-inflammatory cytokine TGF-β1 was seen in the ileum of pigs fed pasteurized milk containing hLZ (P = 0.0478), along with an increase in intraepithelial lymphocytes (P = 0.0255), and decrease in lamina propria thickness in the duodenum (P = 0.0001). Based on these results we conclude that consuming pasteurized milk containing hLZ does not induce an inflammatory response and improves the health of the small intestine in pigs.     

Interleukin-1, tumor necrosis factor-alpha,and transforming growth factor-beta 1 and integrative meniscal repair: influences on meniscal cell proliferation and migration

Introduction  

Interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) are up-regulated in injured and osteoarthritic knee joints. IL-1 and TNF-α inhibit integrative meniscal repair; however, the mechanisms by which this inhibition occurs are not fully understood. Transforming growth factor-β1 (TGF-β1) increases meniscal cell proliferation and accumulation, and enhances integrative meniscal repair. An improved understanding of the mechanisms modulating meniscal cell proliferation and migration will help to improve approaches for enhancing intrinsic or tissue-engineered repair of the meniscus. The goal of this study was to examine the hypothesis that IL-1 and TNF-α suppress, while TGF-β1 enhances, cellular proliferation and migration in cell and tissue models of meniscal repair.     

A risk-associated single nucleotide polymorphism of <Emphasis Type="Italic">SMAD7</Emphasis> is common to colorectal,gastric, and lung cancers in a Han Chinese population

SMAD7 has been demonstrated to antagonize TGF-β-mediated fibrosis, carcinogenesis, and inflammation. Two previous genome-wide association studies identified three single nucleotide polymorphisms (SNPs) (rs4939827, rs12953717 and rs4464148) in SMAD7 to be associated with colorectal cancer in a Western population. We conducted the first case–control study in a Han Chinese population to explore the associations between these three SNPs and colorectal, gastric, and lung cancers. Of the three SNPs, only rs12953717 was strongly associated with the three types of cancer, fitting the overdominant model. Compared with the CC/TT (CC combined with TT) genotype, the adjusted odds ratios for the CT genotype were 2.002 (95% CI, 1.250–3.207, P = 0.004), 1.678 (95% CI, 1.048–2.689, P = 0.031), 3.825 (95% CI, 2.310–6.335, P < 1 × 10⁻⁴), and 2.294 (95% CI, 1.537–3.343, P < 1 × 10⁻⁴), respectively, for colorectal, gastric, lung, and combined cancers. These outcomes suggest that rs12953717 is a common risk marker of these three types of cancer in the Han Chinese.     

Rubella vaccine-induced cellular immunity: evidence of associations with polymorphisms in the Toll-like, vitamin A and D receptors, and innate immune response genes

Toll-like, vitamin A and D receptors and other innate proteins participate in various immune functions. We determined whether innate gene-sequence variations are associated with rubella vaccine-induced cytokine immune responses. We genotyped 714 healthy children (11–19 years of age) after two doses of rubella-containing vaccine for 148 candidate SNP markers. Rubella virus-induced cytokines were measured by ELISA. Twenty-two significant associations (range of P values 0.002–0.048) were found between SNPs in the vitamin A receptor family (RARA, RARB, TOP2B and RARG), vitamin D receptor and downstream mediator of vitamin D signaling (RXRA) genes and rubella virus-specific (IFN-γ, IL-2, IL-10, TNF-α, and GM-CSF) cytokine immune responses. A TLR3 gene promoter region SNP (rs5743305, −8441A > T) was associated with rubella-specific GM-CSF secretion. Importantly, SNPs in the TRIM5 gene coding regions, rs3740996 (His43Tyr) and rs10838525 (Gln136Arg), were associated with an allele dose-related secretion of rubella virus-specific TNF-α and IL-2/GM-CSF, respectively, and have been previously shown to have functional consequences regarding the antiviral activity and susceptibility to HIV-1 infection. We identified associations between individual SNPs and haplotypes in, or involving, the RIG-I (DDX58) gene and rubella-specific TNF-α secretion. This is the first paper to present evidence that polymorphisms in the TLR, vitamin A, vitamin D receptor, and innate immunity genes can influence adaptive cytokine responses to rubella vaccination.     

TGF-β1 reverses PDGF-stimulated migration of human aortic smooth muscle cells in vitro

Summary Platelet-derived growth factor (PDGF) and transforming growth factor beta-1(TGF-β1) were tested separately or together for the ability to stimulate migration of human aortic vascular smooth muscle cells (VSMC). PDGF (10 ng/ml) stimulated migration of VSMC over a 48-h period. TGF-β1 (10 ng/ml) had no effect on migration during the same period. VSMC exposed simultaneously to both TGF-β1 and PDGF exhibited diminished migration (50%) when compared to cells treated only with PDGF. Cells that migrated in the presence of PDGF possessed short actin cables that extended from cellular processes at the leading edge of migrating cells; focal adhesions containing the α_vβ₃/β₅ integrins localized to the same region. Cells grown in the presence of TGF-β1 exhibited long, intensely stained actin filaments that spanned the entire length of the cell and were similar to untreated control VSMC. Focal adhesions containing α_vβ₃/β₅ distributed evenly on the basal surface in both TGF-β1-treated cells and control cultures. Cellular responses to PDGF were mitigated when TGF-β1 was present in the culture medium. VSMC grown in the presence of both PDGF and TGF-β1 exhibited elongated actin filaments that were similar to nonmotile TGF-β1-treated cultures. Concomitant exposure of VSMC to PDGF and TGF-β1 resulted in focal adhesions that distributed evenly on the lower cell surface. This study suggests that TGF-β1 can partially reverse the stimulatory effect of PDGF on VSMC migration in vitro by modifying the actin cytoskeleton and the distribution of the α _vβ₃/β₅ integrins.     

Evaluation of a SNP map of 6q24–27 confirms diabetic nephropathy loci and identifies novel associations in type 2 diabetes patients with nephropathy from an African-American population

Previously, we performed a genome scan for type 2 diabetes (T2DM) using 638 African-American (AA) affected sibling pairs from 247 families; non-parametric linkage analysis suggested evidence of linkage at 6q24–27 (LOD 2.26). To comprehensively evaluate this region, we performed a two-stage association study by first constructing a SNP map of 754 SNPs selected from HapMap on the basis of linkage disequilibrium (LD) in 300 AAT2DM end-stage renal disease (ESRD) subjects, 311 AA controls, 43 European American controls and 45 Yoruba Nigerian samples (Set 1). Replication analyses were conducted in an independent population of 283 AA T2DM-ESRD subjects and 282 AA controls (Set 2). In addition, we adjusted for the impact of admixture on association results by using ancestry informative markers (AIMs). In Stage 1, 137 (18.2%) SNPs showed nominal evidence of association (P < 0.05) in one or more of tests of association: allelic (n = 33), dominant (n = 36), additive (n = 29), or recessive (n = 34) genotypic models, and 2- (n = 47) and 3-SNP (n = 43) haplotypic analyses. These SNPs were selected for follow-up genotyping. Stage 2 analyses confirmed association with a predicted 2-SNP “risk” haplotype in the PARK2 gene. Also, two intergenic SNPs showed consistent genotypic association with T2DM-ESRD: rs12197043 and rs4897081. Combined analysis of all subjects from both stages revealed nominal associations with 17 SNPs within genes, including suggestive associations in ESR1 and PARK2. This study confirms known diabetic nephropathy loci and identifies potentially novel susceptibility variants located within 6q24–27 in AA. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.