Correlations of ANP genetic polymorphisms and serum levels with ischemic stroke risk: a meta-analysis

The relationship between polymorphism of insulin-like growth factor I gene and susceptibility to type 2 diabetes in Uygur population, Xinjiang, China

Background

Type 2 diabetes (T2DM) susceptibility varies among different populations and is affected by gene single nucleotide polymorphism (SNP). Insulin-like growth factor (IGF)-1 gene, which has many SNP loci, is involved in T2DM pathogenesis. However, the relationship of IGF-1 gene polymorphism with T2DM in Uyghur population is less studied.

Objective

To investigate the relationship between T2DM susceptibility and polymorphism of IGF-1 gene in Uyghur population of Xinjiang, China.

Methods

This study enrolled 220 cases (122 males (55.46%) and 98 females (44.54%); mean age of 53.40 ± 10.94 years) of T2DM patients (T2DM group) and 229 (124 males (54.15%) and 105 females (45.85%); mean age of 51.64 ± 10.48 years) healthy controls (control group). Biochemical indexes were determined. IGF-1 gene polymorphism was analyzed by SNP genotyping.

Results

The levels of TG, HDL, LDL, BUN, and Cr were statistically significant between the T2DM group and the control group. In terms of IGF-1 polymorphism, T2DM group had higher frequency of AA genotype (OR = 2.40, 95% CI = 1.19–4.84) and allele A (OR = 1.55, 95% CI = 1.17–2.06) of rs35767 loci, suggesting that rs35767 is related to the occurrence of T2DM. A total of 5 gene interaction models was obtained through analyzing the interaction of 5 SNP loci with the GMDR method. Among them, the two-factor model that included rs35767 locus and rs5742694 locus had statistical difference with a large cross-validation consistency (10/10). The combination of GG/CC, GA/AA, AA/AA, and AA/AC genotype was in high-risk group, whereas the combination of GG/AA, GG/AC, GA/AC and GA/CC genotype was in the low-risk group. The risk of T2DM in the high-risk group was 2.165 times than that of the low-risk group (OR = 2.165, 95% CI = 1.478–3.171).

Conclusion

TG, HDL, LDL, BUN, and Cr are influencing factors of T2DM in Uyghur population. The rs35767 locus of IGF-1 gene may be associated with T2DM in Uyghur population. The high-risk group composing of rs35767 locus and rs5742694 locus has a higher risk of T2DM.

Association between NPPA promoter methylation and hypertension: results from Gusu cohort and replication in an independent sample

Background

Atrial natriuretic peptide (ANP), one of the main members of the natriuretic peptides system, has been associated with hypertension and related complications, but the underlying molecular mechanisms are not very clear. Here, we aimed to examine whether DNA methylation, a molecular modification to the genome, of the natriuretic peptide A gene (NPPA), the coding gene of ANP, was associated with hypertension.

Methods

Peripheral blood DNA methylation of NPPA promoter was quantified by target bisulfite sequencing in 2498 community members (mean aged 53 years, 38% men) as a discovery sample and 1771 independent participants (mean aged 62 years, 54% men) as a replication sample. In both samples, we conducted a single CpG association analysis, followed by a gene-based association analysis, to examine the association between NPPA promoter methylation and hypertension, adjusting for age, sex, education level, cigarette smoking, alcohol consumption, obesity, fasting glucose, and lipids. Multiple testing was controlled by the false discovery rate approach.

Results

Of the 9 CpG loci assayed, hypermethylation at 5 CpGs (CpG1, CpG3, CpG6, CpG8, and CpG9) was significantly associated with a lower odds of prevalent hypertension in the discovery sample, and one CpG methylation (CpG1 located at Chr1:11908353) was successfully replicated in the replication sample (OR = 0.82, 95%CI 0.74–0.91, q = 0.002) after adjusting for covariates and multiple testing. The gene-based analysis found that DNA methylation of the 9 CpGs at NPPA promoter as a whole was significantly associated with blood pressure and prevalent hypertension in both samples (all P < 0.05).

Conclusions

DNA methylation levels at NPPA promoter were decreased in Chinese adults with hypertension. Aberrant DNA methylation of the NPPA gene may participate in the mechanisms of hypertension.

ScaI atrial natriuretic peptide gene polymorphisms and their possible association with postoperative atrial fibrillation - a preliminary report

INTRODUCTION

Atrial fibrillation (AF) is a frequently encountered complication after coronary artery bypass grafting (CABG), but its underlying mechanisms are still unclear. The natriuretic peptides have been reported as markers for predicting the occurrence of postoperative AF. This study evaluates whether the ScaI ANP gene polymorphisms predict the occurrence of postoperative AF.

MATERIAL AND METHODS

A prospective study of 203 consecutive patients with coronary artery disease undergoing elective CABG was undertaken for atrial natriuretic peptide (ANP) ScaI gene polymorphism. Several perioperative data were analysed. Postoperative AF was defined as lasting for at least 15 min, confirmed by 12-lead ECG and occurring within 6 postoperative days. The ScaI polymorphism of the ANP gene was determined by polymerase chain reaction (PCR). Size-dependent separation of the PCR products on a polyacrylamide gel was followed by staining with ethidium bromide.

RESULTS

The total frequency of AF was 19.7%. The frequencies of ScaI ANP gene polymorphisms were as follows: A1A1 4.90%, A1A2 59.60% and A2A2 35.46%. In order to assess the hypothesis that the A2 allele is a marker of increased risk of postoperative atrial fibrillation, the odds ratio (OR) was calculated: A2 vs. non-A2, OR = 0.98 (0.23-4.1), p = 0.97, which was not significant. The odds ratios for A2A2 and A1A1 were not significant either: A2A2 vs. non-A2A2, OR = 1.11 (0.54-2.29), p = 0.76, and A1A1 vs. non-A1A1, OR = 1.17 (0.23-5.92), p = 0.84.

CONCLUSIONS

ANP genotype did not predispose to the incidence of "new-onset" AF.

C2238/αANP modulates apolipoprotein E through Egr-1/miR199a in vascular smooth muscle cells in vitro

Subjects carrying the T2238C ANP gene variant have a higher risk to suffer a stroke or myocardial infarction. The mechanisms through which T2238C/αANP exerts detrimental vascular effects need to be fully clarified. In the present work we aimed at exploring the impact of C2238/αANP (mutant form) on atherosclerosis-related pathways. As a first step, an atherosclerosis gene expression macroarray analysis was performed in vascular smooth muscle cells (VSMCs) exposed to either T2238/αANP (wild type) or C2238/αANP. The major finding was that apolipoprotein E (ApoE) gene expression was significantly downregulated by C2238/αANP and it was upregulated by T2238/αANP. We subsequently found that C2238/αANP induces ApoE downregulation through type C natriuretic peptide receptor (NPR-C)-dependent mechanisms involving the upregulation of miR199a-3p and miR199a-5p and the downregulation of DNAJA4. In fact, NPR-C knockdown rescued ApoE level. Upregulation of miR199a by NPR-C was mediated by a reactive oxygen species-dependent increase of the early growth response protein-1 (Egr-1) transcription factor. In fact, Egr-1 knockdown abolished the impact of C2238/αANP on ApoE and miR199a. Of note, downregulation of ApoE by C2238/αANP was associated with a significant increase in inflammation, apoptosis and necrosis that was completely rescued by the exogenous administration of recombinant ApoE. In conclusion, our study dissected a novel mechanism of vascular damage exerted by C2238/αANP that is mediated by ApoE downregulation. We provide the first demonstration that C2238/αANP downregulates ApoE in VSMCs through NPR-C-dependent activation of Egr-1 and the consequent upregulation of miR199a. Restoring ApoE levels could represent a potential therapeutic strategy to counteract the harmful effects of C2238/αANP.