PPARGC1A rs3736265 G>A polymorphism is associated with decreased risk of type 2 diabetes mellitus and fasting plasma glucose level

Association between PPARγ, PPARGC1A, and PPARGC1B genetic variants and susceptibility of gastric cancer in an Eastern Chinese population

PURPOSE

Previous studies showed that peroxisome proliferator-activated receptor gamma (PPARγ) and PPARγ coactivator1 family (PPARGC1A and PPARGC1B) gene single nucleotide variants (SNVs)were strongly associated with cancer susceptibility. The purpose of this study was to investigate the association of PPARγ, PPARGC1A, and PPARGC1B variants with the risk of gastric cancer (GC).

PATIENTS AND METHODS

We performed a case-control study of 490 GC cases and 1,476 healthy controls from eastern China. PPARγ rs1801282 C > G, rs3856806 C > T, PPARGC1A rs2970847 C > T, rs8192678 C > T and PPARGC1B rs7732671 G > C, rs17572019 G > A SNVs were selected to investigate the association between these SNVs and GC susceptibility. Genotypes of the SNVs were assessed by multiplex fluorescent PCR using a custom-by-design 48-Plex SNPscan^tm Kit.

RESULTS

The PPARγ rs1801282 SNV was associated with a decreased risk for GC (GC vs. CC: odds ratio (OR) = 0.62, 95% confidence interval (95%CI) = 0.42-0.93, adjusted P = 0.019; GC + GG vs. GG: OR = 0.63 95%CI = 0.42-0.93, adjusted P = 0.019; respectively). In addition, stratified analysis revealed that the PPARγ rs1801282 SNV was correlated with the risk of GC in subgroups of age ≥ 61, no smoking, and no alcohol consuming. We also confirmed that the PPARγ rs3856806 C > T SNV promoted the risk of GC in women. The PPARGC1A rs8192678 TT genotype decreased the susceptibility of GC in men. The PPARGC1A rs2970847 C > T SNV decreased the susceptibility of GC in the subgroup of BMI ≥ 24 kg/m². The PPARGC1B rs7732671 G > C and rs17572019 G > A SNVs promoted the risk of GC in the subgroup of BMI ≥ 24 kg/m².

CONCLUSION

This study indicates that the PPARγ, PPARGC1A, and PPARGC1B SNVs may be associated with the susceptibility of GC in eastern Chinese population. Future studies with larger populations, detailed H. pylori infection status for subgroup analysis, and functional study are needed to further clarify the relationship between these SNVs and GC risk.

The role of the PPARG (Pro12Ala) common genetic variant on type 2 diabetes mellitus risk

Background

Type 2 diabetes (T2DM) prevalence has been rapidly increasing in the last decades. T2DM pathogenesis is related to insulin resistance and beta-cell dysfunction. Peroxisome proliferator-activated receptor gamma (PPARG) is concerned about T2DM risk through the involvement in adipocyte differentiation and energy homeostasis. The present study aimed to find the risk associated with a common genetic variant (Pro12Ala) of the PPARG gene in the development of T2DM in a group of the Iranian population.

Methods

Totally, 149 patients with T2DM and 96 healthy individuals were recruited in this case-control study. The genotyping of the genetic variant was carried out using the polymerase chain reaction (PCR) followed by Sanger sequencing.

Results

No significant difference is observed between the CG and GG genotypes frequency of the PPARG variant (P = 0.17) in T2DM patient and the control groups. Furthermore, the frequency of the G allele was similar between case and control groups. The Pro12Ala variant may decrease the risk of diabetic retinopathy (DR) which was not statistically significant. Furthermore, the Pro12Ala variant caused a 27% increase in the risk of diabetes nephropathy (DN) among patients with T2DM but was not significant.

Conclusions

Our findings showed that the PPARG variant could not impact on T2DM development and its complications.

rs10865710 polymorphism in PPARG promoter is associated with the severity of type 2 diabetes mellitus and coronary artery disease in a Chinese population

BACKGROUND

Relationship between polymorphisms in peroxisome proliferator-activated receptor gamma (PPARG) and progression of type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) remains to be clarified.

METHODS

635 subjects were divided into T2DM, CAD, T2DM complicated with CAD (T2DM/CAD) and control groups according to diagnostic criteria. The rs10865710 and rs3856806 polymorphisms were genotyped, and the severity of T2DM and CAD was evaluated for all subjects.

RESULTS

In patients with T2DM, G allele carriers of rs10865710 polymorphism had significantly higher levels of glucose, triglycerides, apolipoprotein B (ApoB) and lipoprotein (a) (Lp(a)) than non-carriers, T allele carriers of rs3856806 polymorphism had significantly higher levels of glucose, low-density lipoprotein cholesterol (LDL-C), ApoB and Lp(a) than non-carriers. In patients with CAD, G allele carriers of rs10865710 polymorphism had significantly higher levels of total cholesterol (TC), ApoB and Lp(a) than non-carriers, T allele carriers of rs3856806 polymorphism had significantly higher levels of body mass index, blood pressure, TC, LDL-C and ApoB than non-carriers. Patients with one or two G alleles of rs10865710 polymorphism had significantly higher levels of Gensini scores and more diseased coronary branches than those patients without CAD. The rs3856806 polymorphism was not associated with CAD severity, but it was found to be significantly associated with T2DM/CAD, T allele frequency was significantly higher in T2DM/CAD group than that in T2DM/CAD-free group.

CONCLUSIONS

The rs10865710 and rs3856806 polymorphisms in PPARG are significantly associated with glucose levels in patients with T2DM. The rs10865710 polymorphism is significantly associated with the severity of CAD, which is possibly mediated by hyperlipidaemia and hyperglycaemia.

Interaction between dietary branched-chain amino acids and genetic risk score on the risk of type 2 diabetes in Chinese

BACKGROUND AND OBJECTIVES

Previous studies have found the important gene-diet interactions on type 2 diabetes (T2D) incident but have not followed branched-chain amino acids (BCAAs), even though they have shown heterogeneous effectiveness in diabetes-related factors. So in this study, we aim to investigate whether dietary BCAAs interact with the genetic predisposition in relation to T2D risk and fasting glucose in Chinese adults.

METHODS

In a case-control study nested in the Harbin Cohort Study on Diet, Nutrition and Chronic Non-Communicable Diseases, we obtained data for 434 incident T2D cases and 434 controls matched by age and sex. An unweighted genetic risk score (GRS) was calculated for 25 T2D-related single nucleotide polymorphisms by summation of the number of risk alleles for T2D. Multivariate logistic regression models and general linear regression models were used to assess the interaction between dietary BCAAs and GRS on T2D risk and fasting glucose.

RESULTS

Significant interactions were found between GRS and dietary BCAAs on T2D risk and fasting glucose (p for interaction = 0.001 and 0.004, respectively). Comparing with low GRS, the odds ratio of T2D in high GRS were 2.98 (95% CI 1.54-5.76) among those with the highest tertile of total BCAA intake but were non-significant among those with the lowest intake, corresponding to 0.39 (0.12) mmol/L versus - 0.07 (0.10) mmol/L fasting glucose elevation per tertile. Viewed differently, comparing extreme tertiles of dietary BCAAs, the odds ratio (95% CIs) of T2D risk were 0.46 (0.22-0.95), 2.22 (1.15-4.31), and 2.90 (1.54-5.47) (fasting glucose elevation per tertile: - 0.23 (0.10), 0.18 (0.10), and 0.26 (0.13) mmol/L) among participants with low, intermediate, and high genetic risk, respectively.

CONCLUSIONS

This study indicated that dietary BCAAs could amplify the genetic association with T2D risk and fasting glucose. Moreover, higher BCAA intake showed positive association with T2D when genetic predisposition was also high but changed to negative when genetic predisposition was low.

Associations Between microRNA Polymorphisms and Development of Coronary Artery Disease: A Case-Control Study

Coronary artery disease (CAD), a common cardiovascular disease, has become a vital cause of mortality worldwide. Genetic microRNA (miR) polymorphisms might contribute to CAD susceptibility. In this study, we selected miR-146a, miR-196a2, and miR-499 single nucleotide polymorphisms and conducted a case-control study. In total, 505 CAD cases and 1109 controls were recruited. We used SNPscan™ genotyping assay to obtain genotyping of miR rs2910164, rs11614913, and rs3746444 variants. We found that miR-196a2 rs11614913 T > C decreased the susceptibility of myocardial infarction (MI) (TC vs. TT: adjusted p = 0.007 and CC/TC vs. TT: adjusted p = 0.012). In female subgroup, our results indicated that miR-196a2 rs11614913 T > C variants might also decrease the susceptibility of CAD (TC vs. TT: adjusted p = 0.017 and TC/CC vs. TT: adjusted p = 0.015). In summary, these results suggest that miR-196a2 rs11614913 T > C locus decreases the susceptibility of CAD in female and MI subgroups. However, further studies are needed to validate the potential associations of miR-196a2 rs11614913 locus with CAD.

Correlation Between PPARGC1A Gene Rs8192678 G>A Polymorphism and Susceptibility To Type-2 Diabetes

Objective

To systematically investigate the correlation between the G>A polymorphism of the peroxisome proliferator-activated receptor γ coactivator 1α (PPARGC1A or PGC-1alpha) gene rs8192678 locus and the susceptibility to type-2 diabetes mellitus (T2DM).

Methods

The inclusion and exclusion criteria and retrieval strategies of original literatures were formulated. Then, subjects and free words “PPARGC1A”,”gene polymorphism”, and “T2DM” were retrieved from the PubMed, EMBASE, and Cochrane Library databases. Case-control studies on the G>A polymorphism of the PPARGC1A gene rs8192678 locus and susceptibility to T2DM were included for the meta-analysis.

Results

The number of cases in the T2DM group and control group was 5,607 and 7,596, respectively. The meta-analysis revealed that the PPARGC1A gene rs8192678 locus G>A polymorphism is associated with susceptibility to T2DM. There are differences in each group of genetic models, of which three groups of genetic models are highly significant. In the allele model, OR=1.249, 95% CI: 1.099-1.419, and P=0.001. In the dominant inheritance model, OR=1.364, 95% CI: 1.152-1.614, and P=0.000. In the additive inheritance model, OR=0.828, 95% CI: 0.726-0.945, and P=0.005. And one group is significant, in the recessive inheritance model, OR=1.187, 95% CI: 1.021-1.381, and P=0.026.

Conclusion

In Western Asian, South Asian, European and African populations, the A allele of the PPARGC1A gene rs8192678 locus may be one of the risk factors for T2DM.

Systematic Meta-analysis Revealed an Association of PGC-1α rs8192678 Polymorphism in Type 2 Diabetes Mellitus

Background

Genome-wide association study (GWAS) provides an unprecedented opportunity to reveal substantial genetic contribution to type 2 diabetes mellitus (T2DM) and glycemic identification of allelic heterogeneity and population-specific genetic variants, yet it also faces difficulty due to the vast amount of potential confounding factors and limited availability of clinical data. To identify responsible susceptibility loci and genomic polymorphism for T2DM and glycemic traits, we have systematically investigated a genome-wide association study related to T2DM. Although GWAS has captured many common genetic variations, which are related to T2DM, each risk allele (RA) of single-nucleotide polymorphisms (SNPs) at these loci is not conclusive. Therefore, it is common to present a combination of several SNPs to infer T2DM risk, yet it is still insufficient to be deterministic. To streamline the identification of a deterministic genetic variation in T2DM, we developed this meta-analysis as a showcase to comprehensively identify the association between cumulative RAs and T2DM risk by combining different studies in reported literature and databases. After all, we identified that PGC-1α rs8192678 polymorphism can be considered as a potentially deterministic biomarker in T2DM risk. Previous studies have potentially linked PGC-1α rs8192678 polymorphism to type 2 diabetes mellitus (T2DM) risk, but the results remain inconsistent in different populations and are not conclusive. We developed a new meta-analysis approach to systematically identify the association between PGC-1α rs8192678 polymorphism and T2DM, and we have comprehensively assessed different ethnic groups to validate our findings.

Methods

We performed comprehensive information retrieval and knowledge discovery meta-analysis by searching extensively published literature and different electronic databases to acquire eligible studies for the above association study. We developed a method to use pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) in five genetic models (allelic, dominant, recessive, homozygous, and heterozygous genetic models) to identify the relationship among ethnicity subgroup analyses comprehensively.

Results

We identified 20 eligible studies consisting of 16,182 subjects (8,038 cases and 8,144 controls) in our meta-analysis. PGC-1α rs8192678 polymorphisms of all subjects showed a significant association with T2DM susceptibility under all genetic models: allelic (OR: 1.24, 95% CI: 1.13-1.35), dominant (OR: 1.27, 95% CI: 1.14-1.42), recessive (OR: 1.24, 95% CI: 1.14-1.36), homozygous (OR: 1.40, 95% CI: 1.20-1.64), and heterozygous (OR: 1.20, 95% CI: 1.06-1.35). In the subgroup analysis, we identified a significant association between PGC-1α rs8192678 polymorphism and T2DM in the Caucasian and Indian populations under all genetic models we investigated. This is the most comprehensive study of the subject to date.

Conclusion

Our development of meta-analysis revealed that the minor allele (A) carriers, especially AA genotype carriers, can lead to risk of T2DM in the Caucasian and Indian populations. This is the first report that such risk has been confirmed. Our finding shed new light into the genetic alteration in T2DM.

CNDP1, NOS3, and MnSOD Polymorphisms as Risk Factors for Diabetic Nephropathy among Type 2 Diabetic Patients in Malaysia

Type 2 diabetes mellitus (T2DM) is associated with a high incidence of nephropathy. The aim of this study was to investigate the association of a genetic polymorphism of carnosinase (CNDP1-D18S880 and -rs2346061), endothelial nitric oxide synthase (NOS3-rs1799983), and manganese superoxide dismutase (MnSOD-rs4880) genes with the development of diabetic nephropathy among Malaysian type 2 diabetic patients. A case-control association study was performed using 652 T2DM patients comprising 227 Malays (without nephropathy = 96 and nephropathy = 131), 203 Chinese (without nephropathy = 95 and nephropathy = 108), and 222 Indians (without nephropathy = 136 and nephropathy = 86). DNA sequencing was performed for the D18S880 of CNDP1, while the rest were tested using DNA Sequenom MassARRAY to identify the polymorphisms. DNA was extracted from the secondary blood samples taken from the T2DM patients. The alleles and genotypes were tested using four genetic models, and the best mode of inheritance was chosen based on the least p value. The rs2346061 of CNDP1 was significantly associated with diabetic nephropathy among the Indians only with OR = 1.94 and 95% CI = (1.76–3.20) and fitted best the multiplicative model, while D18S880 was associated among all the three major races with the Malays having the strongest association with OR = 2.46 and 95% CI = (1.48–4.10), Chinese with OR = 2.26 and 95% CI = (1.34–3.83), and Indians with OR = 1.77 and 95% CI = (1.18–2.65) in the genotypic multiplicative model. The best mode of inheritance for both MnSOD and NOS3 was the additive model. For MnSOD-rs4880, the Chinese had OR = 2.8 and 95% CI = (0.53–14.94), Indians had OR = 2.4 and 95% CI = (0.69–2.84), and Malays had OR = 2.16 and 95% CI = (0.54–8.65), while for NOS3-rs1799983, the Indians had the highest risk with OR = 3.16 and 95% CI = (0.52–17.56), followed by the Chinese with OR = 3.55 and 95% CI = (0.36–35.03) and the Malays with OR = 2.89 and 95% CI = (0.29–28.32). The four oxidative stress-related polymorphisms have significant effects on the development of nephropathy in type 2 diabetes patients. The genes may, therefore, be considered as risk factors for Malaysian subjects who are predisposed to T2DM nephropathy.

Association of PPARG Gene Polymorphisms Pro12Ala with Type 2 Diabetes Mellitus: A Meta-analysis

BACKGROUND

Previous studies suggested that the single nucleotide polymorphisms of Pro12Ala located within the PPARG gene were significantly associated with the T2DM. Recently, the genetic studies on Pro12Ala were conducted in the different ethnic groups and the results of each study were shown to be inconsistent. Moreover, the systematic review has not been updated since 2000.

OBJECTIVE

To further validate the risk of Pro12Ala for T2DM disease based on the genetic data.

METHODS

The genetic studies on the Pro12Ala in the T2DM were searched in the PubMed and PMC database from January 2000 to October 2017. The meta-analysis was conducted with the CMA software.

RESULTS

The meta-analysis collected 14 studies including 20702 cases and 36227 controls. The combined analysis of all studies found that Pro12Ala was shown to be significantly associated with T2DM and the Ala allele played the increasing risks for the disease. Nevertheless, publication bias was detected in the combined analysis. The subgroup analysis indicated that Pro12Ala was found to be significant in the Caucasian and Chinese population. There was no heterogeneity and publication bias in these two groups.

CONCLUSION

The meta-analysis confirmed the evidence that the Pro12Ala was the susceptible variant for the decreasing risks for the T2DM.

Association of Kir6.2 gene rs5219 variation with type 2 diabetes: A meta-analysis of 21,464 individuals

AIMS

rs5219 is in Potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11) E23K gene, located at 11p15.1. Researches on the association between rs5219 gene polymorphism with type 2 diabetes mellitus (T2DM) were performed extensively, but the results remain controversial. To investigate the relationship, a meta-analysis involving 21,464 individuals was conducted.

METHODS

Odds ratios (OR) and 95% confidence intervals (CI) were used to assess the strength of this association. Publication bias was evaluated with Begg's test. Our research includes three gene models: allelic genetic model (K-allele vs. E-allele), recessive genetic model (KK vs. EK+EE) and dominant genetic model (EE vs. EK+KK).

RESULTS

In allelic genetic model, subgroup analysis demonstrated rs5219 K-allele was relevant to T2DM risk in Caucasian (OR: 1.16, 95% CI: 1.09-1.24, P=0.000) and East Asian (OR: 1.19, 95% CI: 1.13-1.26, P=0.000), recessive genetic model indicated rs5219 KK genotype was related to T2DM risk in Caucasian, East Asian, South Asian, and North African (OR: 1.27, 95% CI: 1.17-1.38, P=0.000), dominant genetic model pointed out rs5219 EE genotype was an opposite association with T2DM risk in Caucasian (OR: 0.86, 95% CI: 0.78-0.94, P=0.001). No obvious evidence of publication bias was found.

CONCLUSIONS

There was a believable evidence to verify that rs5219 variation was associated with T2DM.

Linking Metabolic Disease With the PGC-1α Gly482Ser Polymorphism

Peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) is a highly conserved transcriptional coactivator enriched in metabolically active tissues including liver, adipose, pancreas, and muscle. It plays a role in regulating whole body energy metabolism and its deregulation has been implicated in type 2 diabetes (T2D). A single nucleotide variant of the PPARGC1A gene (rs8192678) is associated with T2D susceptibility, relative risk of obesity and insulin resistance, and lower indices of β cell function. This common polymorphism is within a highly conserved region of the bioactive protein and leads to a single amino acid substitution (glycine 482 to serine). Its prevalence and effects on metabolic parameters appear to vary depending on factors including ethnicity and sex, suggesting important interactions between genetics and cultural/environmental factors and associated disease risk. Interestingly, carriers of the serine allele respond better to some T2D interventions, illustrating the importance of understanding functional impacts of genetic variance on PGC-1α when targeting this pathway for personalized medicine. This review summarizes a growing body of literature surrounding possible links between the PGC-1α Gly482Ser single nucleotide polymorphism and diabetes, with focus on key clinical findings, affected metabolic systems, potential molecular mechanisms, and the influence of geographical or ethnic background on associated risk.

The relationship between IGF2BP2 and PPARG polymorphisms and susceptibility to esophageal squamous-cell carcinomas in the eastern Chinese Han population

The aim of this case–control study was to assess whether PPARG and IGF2BP2 polymorphisms confer susceptibility to esophageal squamous-cell carcinoma (ESCC). A total of 507 patients pathologically confirmed for ESCC and 1,496 age-, sex-, and residence-matched healthy individuals were enrolled. The PPARG rs1801282 C>G and rs3856806 C>T and IGF2BP2 rs1470579 A>C and rs4402960 G>T polymorphisms were selected and genotyped by SNPscan genotyping assays. Multivariable logistic analysis suggested that the PPARG rs3856806 C>T polymorphism might increase the risk of ESCC. In different stratified analyses, there were significant associations between PPARG rs3856806 C>T and risk of ESCC in female, never-smoking, drinking, and never-drinking subgroups. In addition, we also found that PPARG rs1801282 C>G increased ESCC risk in the never-smoking subgroup. There was significant difference in C_rs1470579G_rs4402960C_rs1801282C_rs3856806-haplotype distribution among ESCC cases and control subjects. In conclusion, our findings highlight that PPARG rs1801282 C>G and rs3856806 C>T polymorphisms are candidates for susceptibility to ESCC in the eastern Chinese Han population. The C_rs1470579G_rs4402960C_rs1801282C_rs3856806 haplotype is associated with susceptibility to ESCC.