A sex-specific effect of the CYP17A1 SNP rs11191548 on blood pressure in Chinese children

The CYP17A1 gene polymorphisms are associated with hypercholesterolemia in Han Chinese

BACKGROUND

The CYP17A1 gene has been identified to associate with hypertension in Chinese population. However, the association between CYP17A1 polymorphisms and hypertension-related factors is unclear. The present study aimed to investigate the relation between CYP17A1 single nucleotide polymorphisms (SNPs) and serum lipid profiles.

METHODS

In total, 1350 participants were included in the study. Six SNPs in or near CYP17A1 gene were genotyped in a Han Chinese population in two stages.

RESULTS

There was a statistically significant association of rs1004467 (adjusted odds ratio = 0.783, 95% confidence interval = 0.667-0.919, p < 0.05) and rs11191548 (adjusted odds ratio = 0.788, 95% confidence interval = 0.672-0.925, p < 0.05) with hypercholesterolemia after adjustment for potential factors. Additionally, the rs1004467 minor G-allele and the rs11191548 minor C-allele were significantly associated with the lower serum total cholesterol levels (p < 0.05 for all).

CONCLUSIONS

The rs1004467 and rs11191548 in the CYP17A1 gene are associated with a decreased risk of hypercholesterolemia and lower serum TC levels in Han Chinese.

Associations of the hypertension-related single nucleotide polymorphism rs11191548 with high-density lipoprotein cholesterol and leptin in Chinese children

Background

The genome-wide association study has founded hypertension-related single nucleotide polymorphism (SNP) rs11191548 near CYP17A1 encoding a key enzyme involved in steroid metabolism, but the molecular mechanisms are not understood and the associations of the SNP with hypertension-related traits are not fully described, especially in children. The aim of the present study is to investigate the associations between the SNP and two hypertension-related traits, lipids and leptin.

Methods

We genotyped the SNP in Beijing Child and Adolescent Metabolic Syndrome (BCAMS) study. A total of 3503 children participated in the study.

Results

The SNP rs11191548 was significantly associated with high-density lipoprotein cholesterol (HDL) (P = 0.014 and 0.028, respectively) and leptin (P = 0.011 and 0.026, respectively) under an additive model after adjustment for age, gender, and systolic blood pressure (SBP) or diastolic blood pressure (DBP). There was a statistically significant association of rs11191548 with high leptin after adjustment for age, gender, and SBP or DBP. The P-values remain significant after correction for multiple testing.

Conclusions

We demonstrate for the first time that the SNP rs11191548 near CYP17A1 is associated with HDL and leptin in Chinese children. These novel findings provide important evidence that HDL and leptin maybe possibly mediate the process of CYP17A1 involved in hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0523-y) contains supplementary material, which is available to authorized users.

Association of CYP17A1 Genetic Polymorphisms and Susceptibility to Essential Hypertension in the Southwest Han Chinese Population

Background

The CYP17A1 gene encodes for cytochrome P450 enzyme CYP17A1, which is involved with the steroidogenic pathway including mineralocorticoids. The CYP17A1 polymorphisms might affect enzyme activity, then leading to a state of mineralocorticoid 11-deoxycorticosterone excess characterized by hypertension, suppressed plasma renin activity, and low aldosterone concentrations. The aim of this study was to investigate the contribution of CYP17A1 polymorphisms in inducing the susceptibility to essential hypertension among the Southwest Han Chinese population.

Material/Methods

Eight single nucleotide polymorphisms of CYP17A1 were genotyped in a case-control study for samples by polymerase chain reaction-restriction fragment length polymorphism analysis.

Results

The polymorphisms rs11191548 and rs4919687 were significantly associated with hypertension risk, which was confirmed by systolic and diastolic blood pressure distribution analyses between different genotype groups, and these two polymorphisms were found in linkage disequilibrium. The rs4919687 polymorphism was estimated to cause the destruction of exonic splicing silencer (ESR and Motif 3) sites and to transform the transcription factor AREB6 binding site, respectively, in the bioinformatics analyses. The haplotypes rs4919686A-rs3740397G -rs4919687C-rs743572C-rs11191548C and rs4919686A-rs3740397G-rs4919687T-rs743572C- rs11191548T were found to be susceptible to essential hypertension.

Conclusions

Our findings suggest that the CYP17A1 polymorphisms could be a genetic risk factor for essential hypertension among the Yunnan Han Chinese population, which would have implications for the treatment of this complex disorder.

Effect of n-3 and n-6 Polyunsaturated Fatty Acids on Microsomal P450 Steroidogenic Enzyme Activities and In Vitro Cortisol Production in Adrenal Tissue From Yorkshire Boars

Dysregulation of adrenal glucocorticoid production is increasingly recognized to play a supportive role in the metabolic syndrome although the mechanism is ill defined. The adrenal cytochrome P450 (CYP) enzymes, CYP17 and CYP21, are essential for glucocorticoid synthesis. The omega-3 and omega-6 polyunsaturated fatty acids (PUFA) may ameliorate metabolic syndrome, but it is unknown whether they have direct actions on adrenal CYP steroidogenic enzymes. The aim of this study was to determine whether PUFA modify adrenal glucocorticoid synthesis using isolated porcine microsomes. The enzyme activities of CYP17, CYP21, 11β-hydroxysteroid dehydrogenase type 1, hexose-6-phosphate dehydrogenase (H6PDH), and CYP2E1 were measured in intact microsomes treated with fatty acids of disparate saturated bonds. Cortisol production was measured in a cell-free in vitro model. Microsomal lipid composition after arachidonic acid (AA) exposure was determined by sequential window acquisition of all theoretical spectra-mass spectrometry. Results showed that adrenal microsomal CYP21 activity was decreased by docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), eicosapentaenoic acid, α-linolenic acid, AA, and linoleic acid, and CYP17 activity was inhibited by DPA, DHA, eicosapentaenoic acid, and AA. Inhibition was associated with the number of the PUFA double bonds. Similarly, cortisol production in vitro was decreased by DPA, DHA, and AA. Endoplasmic enzymes with intraluminal activity were unaffected by PUFA. In microsomes exposed to AA, the level of AA or oxidative metabolites of AA in the membrane was not altered. In conclusion, these observations suggest that omega-3 and omega-6 PUFA, especially those with 2 or more double bonds (DPA, DHA, and AA), impede adrenal glucocorticoid production.

Sex-specific association of rs4746172 of VCL gene with hypertension in two Han populations from Southern China

Hypertension is the most common and lethal risk factor for cardiovascular disease (CVD). Numerous variants have been associated with hypertension, however, most of which failed to get replication due to ethnic differences. In this study, we analyzed associations of 10 newly reported single nucleotide polymorphisms (SNPs) in Europeans with hypertension in Chinese. A total of 1766 samples consisting of 880 subjects with hypertension and 886 controls were collected and the SNPs were genotyped using multiple assays based on the SNaPshot mini-sequencing approach. Our results revealed a significant genotypic association of rs4746172 of VCL with hypertension with a lower frequency of minor allele in male subjects (OR = 0.70, 95% CI: 0.54-0.92, p = 0.011) but not in females. To validate the result, we genotyped the SNPs in another Chinese population with 546 individuals, and got a consistent association for the rs4746172 (OR = 0.56, 95% CI: 0.38-0.82, p = 2.4 × 10(-3)) in males. The VCL-encoding protein was involved in cardiomyopathy that associated with hypertension, therefore our results suggest the rs4746172 of VCL may be a novel target for clinical interventions to reduce CVD risk by regulating blood pressure in male Chinese.

Pathophysiology of hypertension in obese children: a systematic review

Hypertension is increasingly common in overweight and obese children. The mechanisms behind the development of hypertension in obesity are complex, and evidence is limited. In order to effectively treat obese children for hypertension, it is important to have a deeper understanding of the pathophysiology of hypertension in obese children. The present review summarizes the main factors associated with hypertension in obese children and discusses their potential role in its pathophysiology. Systematic searches were conducted in PubMed and EMBASE for articles published up to October 2014. In total, 60 relevant studies were included. The methodological quality of the included studies ranged from weak to strong. Several factors important in the development of hypertension in obese children have been suggested, including endocrine determinants, such as corticosteroids and adipokines, sympathetic nervous system activity, disturbed sodium homeostasis, as well as oxidative stress, inflammation and endothelial dysfunction. Understanding the pathophysiology of hypertension in overweight and obese children is important and could have implications for its screening and treatment. Based on solely cross-sectional observational studies, it is impossible to infer causality. Longitudinal studies of high methodological quality are needed to gain more insight into the complex mechanisms behind the development of hypertension in obese children.

A Single Nucleotide Polymorphism near the CYP17A1 Gene Is Associated with Left Ventricular Mass in Hypertensive Patients under Pharmacotherapy

Cytochrome P450 17A1 (CYP17A1) catalyses the formation and metabolism of steroid hormones. They are involved in blood pressure (BP) regulation and in the pathogenesis of left ventricular hypertrophy. Therefore, altered function of CYP17A1 due to genetic variants may influence BP and left ventricular mass. Notably, genome wide association studies supported the role of this enzyme in BP control. Against this background, we investigated associations between single nucleotide polymorphisms (SNPs) in or nearby the CYP17A1 gene with BP and left ventricular mass in patients with arterial hypertension and associated cardiovascular organ damage treated according to guidelines. Patients (n = 1007, mean age 58.0 ± 9.8 years, 83% men) with arterial hypertension and cardiac left ventricular ejection fraction (LVEF) ≥ 40% were enrolled in the study. Cardiac parameters of left ventricular mass, geometry and function were determined by echocardiography. The cohort comprised patients with coronary heart disease (n = 823; 81.7%) and myocardial infarction (n = 545; 54.1%) with a mean LVEF of 59.9% ± 9.3%. The mean left ventricular mass index (LVMI) was 52.1 ± 21.2 g/m2.7 and 485 (48.2%) patients had left ventricular hypertrophy. There was no significant association of any investigated SNP (rs619824, rs743572, rs1004467, rs11191548, rs17115100) with mean 24 h systolic or diastolic BP. However, carriers of the rs11191548 C allele demonstrated a 7% increase in LVMI (95% CI: 1%-12%, p = 0.017) compared to non-carriers. The CYP17A1 polymorphism rs11191548 demonstrated a significant association with LVMI in patients with arterial hypertension and preserved LVEF. Thus, CYP17A1 may contribute to cardiac hypertrophy in this clinical condition.

Sex-dependent regulation of cytochrome P450 family members Cyp1a1, Cyp2e1, and Cyp7b1 by methylation of DNA

Sexual differences are only partially attributable to hormones. Cultured male or female cells, even from embryos before sexual differentiation, differ in gene expression and sensitivity to toxins, and these differences persist in isolated primary cells. Male and female cells from Swiss Webster CWF mice manifest sex-distinct patterns of DNA methylation for X-ist and for cytochrome P450 (CYP; family members 1a1, 2e1m, and 7b1. Dnmt3l is differentially expressed but not differentially methylated, and Gapdh is neither differentially methylated nor expressed. CYP family genes differ in expression in whole tissue homogenates and cell cultures, with female Cyp expression 2- to 355-fold higher and Dnmt3l 12- to 32-fold higher in males. DNA methylation in the promoters of these genes is sex dimorphic; reducing methylation differences reduces to 1- to 6-fold differences in the expression of these genes. Stress or estradiol alters both methylation and gene expression. We conclude that different methylation patterns partially explain the sex-based differences in expression of CYP family members and X-ist, which potentially leads to inborn differences between males and females and their different responses to chronic and acute changes. Sex-differential methylation may have medical effects.

Association of common variants in/near six genes (ATP2B1, CSK, MTHFR, CYP17A1, STK39 and FGF5) with blood pressure/hypertension risk in Chinese children

Recent genome-wide association studies have identified several single-nucleotide polymorphisms (SNPs) that are associated with blood pressure (BP)/hypertension. In this study, we aimed to examine the established associations amongst Chinese children. We genotyped six SNPs (ATP2B1 rs17249754, CSK rs1378942, MTHFR rs1801133, CYP17A1 rs1004467, STK39 rs3754777 and FGF5 rs16998073) in Chinese children (N=3077, age range, 6-18 years). Based on the Chinese age- and sex-specific BP standards, 619 hypertensive cases and 2458 controls with normal BP were identified. Of the six SNPs, only ATP2B1 rs17249754 SNP was significantly associated with the risk of hypertension (allelic odds ratio (OR)=1.25, 95% confidence interval (CI): 1.08-1.44, P=0.003). Although all other SNPs showed a trend towards increasing the BP values and risk of hypertension, there was no statistically significant association after false discovery rate analysis. We calculated the weighted risk score using six SNPs, for systolic BP (SBP), diastolic BP (DBP) and hypertension. Each additional weighted risk score was associated with SBP by 1.18 mm Hg (95% CI=0.62-1.73, P<0.001), but not with the DBP (β=0.28, 95% CI=(-0.15)-0.74), and overall increased the risk of hypertension by 1.19-fold (95% CI=1.04-1.35, P=0.01). The present study confirmed the significant association of ATP2B1 rs17249754 with risk of hypertension among Chinese children, but failed to replicate the association of CSK rs1378942, MTHFR rs1801133, CYP17A1 rs1004467, STK39 rs3754777 and FGF5 rs16998073 with BP/risk of hypertension.

Common polymorphism rs11191548 near the CYP17A1 gene is associated with hypertension and systolic blood pressure in the Han Chinese population

Background The single-nucleotide polymorphism (SNP) rs11191548, near the CYP17A1 gene, has been identified as being associated with hypertension and systolic blood pressure (SBP) in genome-wide association studies (GWAS) in a European population. The CYP17A1 gene encodes cytochrome P450c17alpha and plays an important role in the steroidogenic pathway, which includes mineralocorticoids. Methods We investigated the SNP rs11191548 in a case-control study of 1,102 subjects with essential hypertension (EH) and 1,109 normotensive controls. Results The SNP rs11191548 was significantly associated with hypertension in an additive genetic model (genotypes CC vs. TC vs. TT; odds ratio (OR) = 1.27 (95% CI, 1.10-1.47; P = 0.001)). The ORs of the TC vs. TT and CC vs. TT genotypes were 1.34 (95% CI, 1.10-1.63; P = 0.003) and 1.52 (95% CI, 1.10-2.12; P = 0.014), respectively. The risk C-allele was associated with increased SBP (βadj ± SEM = 1.307±0.515; P = 0.011) levels in the controls and decreased plasma renin activity (PRA) (βadj ± SEM = -0.053±0.016; P = 0.001) in the subjects with EH. In a stratified analysis of renin-angiotensin-aldosterone-system (RAAS)-related antagonists, the C-allele was significantly associated with decreased serum potassium (K(+)) (βadj ± SEM = -0.093±0.028; P = 0.001) and PRA (βadj ± SEM = -0.067±0.023; P = 0.003) levels in patients with EH who were not taking RAAS-related antagonists. These results remained statistically significant after correction for multiple corrections. Conclusions The SNP rs11191548, near the CYP17A1 gene, was associated with hypertension and SBP in a Chinese Han population. The rs11191548 polymorphism was also related to lower PRA and K(+) levels, suggesting that it has an effect on the enzymatic activity of CYP17A1.