Tag polymorphisms of solute carrier family 12 member 3 gene modify the risk of hypertension in northeastern Han Chinese

A Pilot Study of Gene Expression Analysis in Peripheral Blood Mononuclear Cells in Response to a Hypocaloric Mediterranean Diet

Background

Few studies have examined gene expression in peripheral blood mononuclear cells (PBMCs) after a dietary intervention.

Objective

Our study is aimed at evaluating in a pilot study the peripheral blood gene expression in obese patients after weight loss secondary to a hypocaloric Mediterranean diet.

Design

A sample of 11 obese subjects without metabolic syndrome was enrolled. Biochemical, anthropometric parameters and microarray analysis were performed at baseline and after 6 months of dietary intervention.

Results

The mean age was 43.1 ± 6.3 years, and the mean body mass index (BMI) was 38.6 ± 8.1 kg/m². All the next improvements were statistically significant: body weight −7.4 ± 1.9 kg, BMI -2.5 ± 0.2 kg, fat mass −5.7 ± 1.2 kg, waist circumference −5.8 ± 1.2 cm, triglycerides −17.4 ± 6.5 mg/dl, C-reactive protein −3.1 ± 1.5 mg/dL, insulin −2.1 ± 1.0 mUI/L, and HOMA-IR −0.7 ± 0.2 units. We identified 634 differentially expressed genes: 262 genes with relative higher expression levels and 372 with lower expression levels. Cluster analysis showed 35 genes in nutritional disease and 17 genes in endocrine system. The most relevant gene was thyroid peroxidase (TPO), and this gene was overexpressed, and the next genes carbonic anhydrase VI (CA6), caveolin protein 1 (CAV1) and solute carrier family type 12 (SLLC12A3), soluble carrier family type 12 (SLLC12A3), beta 3 receptor (ADRB3), and glutamate receptor ionotropic N methyl D aspartate 2 A (GRIN2A) were all underexpressed.

Conclusion

In PBMC from obese patients after a diet with a Mediterranean pattern, the expression of 634 genes, of the endocrine system and of nutritional disease, is modified.

Thiazide-sensitive Na+-Cl- cotransporter: genetic polymorphisms and human diseases

The thiazide-sensitive Na(+)-Cl(-) cotransporter (TSC) is responsible for the major sodium chloride reabsorption pathway, which is located in the apical membrane of the epithelial cells of the distal convoluted tubule. TSC is involved in several physiological activities including transepithelial ion absorption and secretion, cell volume regulation, and setting intracellular Cl(-) concentration below or above its electrochemical potential equilibrium. In addition, TSC serves as the target of thiazide-type diuretics that are the first line of therapy for the treatment of hypertension in the clinic, and its mutants are also reported to be associated with the hereditary disease, Gitelman's syndrome. This review aims to summarize the publications with regard to the TSC by focusing on the association between TSC mutants and human hypertension as well as Gitelman's syndrome.

Do genetic defects of DNA repair relevant proteins alter susceptibility to hypertension? A case-control study in northeastern Han Chinese

The aim of this study was to examine the individual and interactive associations of five non-synonymous variants of four DNA repair relevant genes (XRCC1, XRCC3, hOGG1, NQO1) with hypertension in a large northeastern Han Chinese population. This was a hospital-based study involving 1009 hypertensive patients and 756 normotensive controls. All five variants satisfied the Hardy-Weinberg equilibrium. With a Bonferroni corrected alpha of 0.05/5, significance was only attained in the genotype (P=0.007) and allele (P=0.006) distributions of rs25487 in XRCC1 gene between patients and controls, with its mutant allele conferring 29% (95% CI: 1.09-1.53; P=0.003), 31% (95% CI: 1.05-1.62; P=0.015) and 66% (95%CI: 1.10-2.52; P=0.016) increased risks of hypertension under the additive, dominant and recessive models, respectively after adjusting for confounders. The frequency of allele combination C-A-C-G-C (alleles in order of rs1799782, rs25487, rs861539, rs1052133 and rs1800566) was significantly higher in patients than in controls (P=0.003), while that of C-G-C-C-C was significantly lower (P=0.001). Interaction analysis failed to identify any suggestive evidence of synergism across five examined variants. Our findings provide evidence for a contributory role of XRCC1 gene rs25487 variant in the development of hypertension, and this variant possibly acted in a recessive pattern.

Interactive contribution of serine/threonine kinase 39 gene multiple polymorphisms to hypertension among northeastern Han Chinese

Serine/threonine kinase 39 (STK39) gene has been reported to be a hypertension-susceptibility gene by a recent genome-wide association study in Western populations. To validate this finding in Chinese, we focused on five well-characterized common polymorphisms in STK39 gene to examine their potential association with hypertension in a large northeastern Han population. This is a hospital-based case-control study involving 1009 hypertensive patients and 756 normotensive controls. Data were analyzed by the Haplo.Stats and multifactor dimensionality reduction (MDR) softwares. The genotype and allele distributions of rs6749447, rs3754777 and rs6433027 differed significantly between patients and controls (P < 0.001) even after the Bonferroni correction. The majority of derived haplotypes also showed remarkable differences between the two groups (P ≤ 0.001). As indicated by MDR analysis, a three-locus model including rs6749447, rs35929607 and rs3754777 was selected as the overall best with a larger testing accuracy of 0.7309 and a maximum cross-validation consistency of 10 (P < 0.001). The utility of this model was reinforced by a Logistic regression analysis. Taken together, our findings suggest the potential interactive role of STK39 gene multiple polymorphisms in the development of hypertension among northeastern Han Chinese.

Genetic variants of the matrix metalloproteinase family genes and risk for hypertension: a case-control study among northeastern Han Chinese

In this study, we sought to examine the association between 10 genetic variants in the matrix metalloproteinase (MMP) family genes and the risk of hypertension among northeastern Han Chinese. This was a hospital-based case-control study involving 1009 sporadic hypertensive patients and 756 age-, gender- and ethnicity-matched normotensive controls. The genotypes of the 10 examined variants were determined by PCR-ligase detection reaction method. The genotype/allele distributions of rs3025058 and rs679620 differed significantly between patients and controls, with a Bonferroni corrected α of 0.05/10. The probability of having hypertension was significant for rs3025058 under the additive (odds ratio; 95% confidence interval; P: 1.33; 1.16-1.53; <0.001) and dominant (1.43; 1.18-1.73; <0.001) models and was significant for rs679620 under the additive (1.27; 1.1-1.46; <0.001) model after adjusting for confounders. In a combined analysis, when compared with the reference group (score<3.5 for unfavorable genotypes), participants in the medium- and high-risk groups had odds ratios that increased to 1.61 (95% CI: 1.25-2.51; P<0.001) and 1.92 (95% CI: 1.54-2.39; P<0.001) after adjustment, respectively. Interaction analysis showed that a three-locus model including rs3025058, rs679620 and rs243865 was the best, with a maximum testing accuracy of 0.6605 and a cross-validation consistency of 10 (P=0.0022). Taken together, our findings suggest that the true association between individual variants and the risk of hypertension may not be revealed until combined analyses of multiple variants from genes involving a specific physiological or cellular function are performed. Moreover, we propose a three-locus model that can best characterize the genetic interactions of the MMP multiple gene family.

The contributory role of angiotensin receptor-like 1 gene multiple polymorphisms in hypertension among northeastern Han Chinese

Background and Objective

Via direct sequencing, we have recently identified six common polymorphisms in angiotensin receptor-like 1 (AGTRL1) gene, and found only two polymorphisms were significantly associated with hypertension in a family-based analysis on 1,015 southern Han Chinese. Extending our previous work and considering the ubiquity of epistasis in determining disease susceptibility, we, in this study, sought to explore the potential interaction of AGTRL1 gene six polymorphisms with hypertension in a large northeastern Han Chinese population.

Methods and Results

This was a case-control study involving 1,009 sporadic hypertensive patients and 756 normotensive controls. Data were analyzed by Haplo.Stats and multifactor dimensionality reduction (MDR) softwares. There were no deviations from Hardy-Weinberg equilibrium for all polymorphisms. The genotypes and alleles of rs7119675 and rs11544374 differed significantly between the two groups (P<0.0005), even after the Bonferroni correction. Under three genetic models, significant association was consistently observed for rs7119675 and rs11544374, and this association was independent of confounding factors. Taking rs7119375 as an example, the odds of having hypertension was 2.46 (95% confidence interval (95% CI): 2.06–2.94), 2.82 (95% CI: 2.29–3.46) and 3.97 (95% CI: 2.37–6.64) under additive, dominant and recessive models (P<0.001), respectively, whereas the adjusted risk estimates were slightly attenuated but still significant. The frequencies of most derived haplotypes differed significantly between patients and controls. Haplotype-phenotype analyses indicated marginal association for triglyceride (P_Sim = 0.011) and total cholesterol (P_Sim = 0.025) in patients and for triglyceride in controls (P_Sim = 0.023). The overall best MDR model included rs11544374, rs7119375 and rs948847 with the maximal testing accuracy of 0.737 and cross-validation consistency of 10 out of 10 (P<0.0001). Further interaction entropy graph suggested that the interaction of rs7119375 with rs11544374 and rs948847 was strongly antagonized.

Conclusions

Our findings demonstrate that AGTRL1 genetic polymorphisms might contribute to the development of hypertension independently and/or through complex interaction.