Genetic and microrna polymorphisms in young South African Indians with coronary artery disease.

Doctor of Philosophy in Medical Biochemistry. University of KwaZulu-Natal, Medical School 2015.The global burden of cardiovascular disease (CVD) is on the increase with coronary artery disease (CAD) estimated to become the leading cause of mortality worldwide by 2020. The age of onset of this chronic disorder is on the decline, particularly in the South African Indian population. Indians in South Africa (SA) have a higher prevalence of premature CAD compared to other ethnic groups in SA. Coronary artery disease is a lifestyle and genetic disease, and the inheritance of genetic variation from one or both parents plays an important role in the risk of an individual developing CAD. Genetic and epigenetic studies are being explored as potential tools for therapeutic interventions against CVDs. The role of single nucleotide polymorphisms (SNP) in microRNAs (miR, miRNA) and molecules regulating epigenetic pathways remains poorly understood. This study investigated SNPs in candidate genes; methylenetetrahydrofolate reductase (MTHFR), sirtuin (SIRT) 1, miR-499, and miR-146a; in young SA Indians with CAD. The study population included 106 SA Indian male CAD patients, 100 sex- and age-matched Indian, and 84 sex- and age-matched Black controls. The MTHFR, miR-146a, and miR-499 SNPs were investigated by PCR-RFLP, whilst a TaqMan SNP Genotyping assay assessed the SIRT1 SNPs. MiR-146a expression was measured by qPCR and western blot was used to assess the expression of NF-κB, IRAK-1, and TRAF-6. Interleukin (IL)-6 levels were analysed using an ELISA. All clinical parameters were obtained from pathology reports. Methylenetetrahydrofolate reductase is involved in folate metabolism and methylation pathways. The MTHFR rs1801133 has been associated with increased levels of homocysteine, a well known risk factor for CAD. Sirtuin 1, histone deacetylase, has been identified as a candidate molecule affecting the epigenetic mechanisms of CAD. Two common SNPs in the SIRT1 gene, rs7895833 and rs1467568, have been associated with several well-established risk factors for CAD. MicroRNAs (miRNAs) are small noncoding RNA molecules that inhibit messenger RNA (mRNA) translation or promoting mRNA degradation. MiR-499 and miR-146a are inflammatory-associated miRNAs. Two miRNA SNPs, miR-146a rs2910164 and miR-499 rs3746444, have been implicated in chronic inflammatory diseases. There was a significant association between the MTHFR variant (T) allele and CAD patients compared to Indian controls (p=0.0353, OR=2.105 95% CI 1.077–4.114). Indian controls presented with a higher frequency of the T allele compared to Black controls (7% vs. 2% respectively, p=0.0515 OR=3.086 95% CI 0.9958–9.564). The variant allele for the two SIRT1 SNPs occurred more frequently in the total Indian group compared to the total Black population (rs1467568: 41% vs. 18.5% respectively, p<0.0001, OR=3.190 95% CI 2.058-40943 and rs7895833: 41% vs. 22% respectively, p<0.0001, OR=2.466 95% CI 1.620–3.755). Indian controls presented with a higher frequency for both SNPs compared to Black controls (rs1467568: 40% vs. 18.5% respectively, p<0.0001, OR=2.996 95% CI 1.850–4.853 and rs7895833: 41% vs. 22% respectively, p<0.0001, OR=2.513 95% CI 1.578–4.004). No difference was seen in the distribution of both SNPs between CAD patients and either control group. The MTHFR and SIRT1 SNPs were not associated with any clinical parameters in CAD patients and controls. The miR-499 variant (G) allele was found at a higher frequency in the total Indian group (34%) compared to the total Black population (22%) (p=0.0070, OR=1.796 95% CI 1.182–2.730). Indian cases presented with higher frequency of the rs3746444 G allele compared to Indian controls (38% vs. 29%, p=0.059, respectively). No differences in genotypic frequency for rs2910164 was found (GG: 45 vs. 47 %, GC: 46 vs. 41 %, CC: 9 vs. 12 %) in controls and patients respectively (odds ratio=1.025; 95 % confidence interval 0.6782–1.550; p=0.9164). The lowest levels of NF-κB and C-reactive protein (hsCRP) were found in patients with the homozygous C allele compared to the heterozygous GC and wildtype variants. Higher levels of miR-499 targets, hsCRP and IL-6, were observed in CAD patients with the variant genotypes compared to those with the wild type genotypes (8.92±1.91 vs. 6.73±0.87 mg/L; p=0.299, 3.02±0.77 vs. 2.18±0.57 pg/mL; p=0.381 respectively). A 6.25-fold increase in miR-146a levels was observed in CAD patients with the CC genotype (relative to controls and patients with the wildtype variant, p<0.0001). These (CC genotype) patients had significantly lower levels of miR-146a targets, IRAK-1 (0.38±0.02; p=0.0072) and TRAF-6 (0.44±0.02; p=0.0146). Taken together, this study provides the frequency distribution of the SNPs in four candidate genes for CAD in young South African Indians compared to Indian and Black controls. The frequency of variant alleles of rs1801133, rs3746444, rs7895833 and rs1467568 was greater in the Indian population compared to Black South Africans. Although no difference in frequency was observed for rs2010164, our results suggest a role for miR-146a in toll-like receptor (TLR) signalling via a negative feedback mechanism involving the attenuation of NF-κB by downregulation of IRAK-1 and TRAF-6. Thus miR-146a can act as a target for therapy towards lowering inflammation in CAD patients

Sirtuin 1 rs1467568 and rs7895833 in South African Indians with early-onset coronary artery disease

BACKGROUND : Sirtuin 1 (SIRT1), a class III histone deacetylase, has been identified as a candidate molecule affecting the epigenetic mechanisms of cardiovascular disease (CVD). Previous studies have shown that some SIRT1 single-nucleotide polymorphisms (SNPs) are associated with body mass index, diabetes, blood pressure, cholesterol metabolism and coronary artery calcification. We investigated two A>G SIRT1 SNPs, rs1467568 and rs7895833, in young South African (SA) Indians with coronary artery disease (CAD) and compared them to Indian and black controls. METHODS : For rs1467568, a total of 287 subjects were recruited into this study (104 CAD patients, 99 age-, gender- and race-matched controls, and 84 age- and gender-matched black controls). For rs7895833, a total of 281 subjects were recruited into this study (100 CAD patients, 99 age-, gender- and race-matched controls, and 82 age- and gender-matched black controls). All patients were male, of Indian ethnicity, stable CAD confirmed on angiography, mean age 37.5 years; range 24–45. All subjects were genotyped using TaqMan SNP genotyping assays. RESULTS : The variant allele for both SNPs was found at a higher frequency in the total Indian group compared to the total black population (rs1467568: 41 vs 18.5%, respectively, p < 0.0001, OR = 3.190, 95% CI: 2.058–40943; and rs7895833: 41 vs 22%, respectively, p < 0.0001, OR = 2.466, 95% CI: 1.620– 3.755). Indian controls presented with a higher frequency for both SNPs compared to black controls (rs1467568: 40 vs 18.5%, respectively, p < 0.0001, OR = 2.996, 95% CI: 1.850– 4.853; and rs7895833: 41 vs 22%, respectively, p < 0.0001, OR = 2.513, 95% CI: 1.578–4.004). No difference was seen in the distribution of both SNPs between CAD patients and either control group. We did not observe any association between the SNPs and clinical parameters in CAD patients and controls. CONCLUSION : Both SNP variant alleles occurred more frequently in SA Indians than in SA blacks. A larger study group and further analysis is required to assess whether these SIRT1 SNPs may serve as risk factors that contribute to Indians developing early-onset CAD.The National Research Foundation (NRF) for a scholarship and UKZN (College of Health Sciences).www.cvja.co.zaam2016Physiolog

MicroRNA-146a rs2910164 is associated with severe preeclampsia in Black South African women on HAART

Abstract Background South African (SA) Black women have a high prevalence of preeclampsia and HIV, both conditions associated with increased inflammation. miR-146a is an inflammatory-associated miR and a common single nucleotide polymorphism (rs2910164) has been associated with several disease conditions. To date, this SNP has not been investigated in SA Black women. We therefore aimed to investigate the miR-146a G\u2009>\u2009C SNP in SA Blacks with preeclampsia, and further examine possible association among preeclamptic (PE) women with HIV infection on HAART. Methods This hospital-based, case-control study included 95 normotensive and 98 PE Black SA women (aged 16\u201346 years old). Patients and controls were genotyped by PCR-RFLP. Using a Cytometric Bead Array assay, serum cytokine levels (including Th1- and Th2-related cytokines) were determined in 4 groups of pregnant women, viz: normotensive, HIV infected, PE\u2009+\u2009HIV infected, and PE women. Results There was no significant association between the miR-146a polymorphism and PE susceptibility in our data. However, in the subgroup analyses, the variant genotypes (GC/CC) were significantly associated with lower severe PE risk ( p \u2009=\u20090.0497), more especially in the presence of HIV and HAART ( p \u2009=\u20090.017). In the normotensive group, the variant genotypes were associated with lower IL-2 in both the total normotensive group (269\u2009\ub1\u20091.26 (36) vs 273\u2009\ub1\u20091.31 (23); p \u2009=\u20090.035) and the PE HIV+ sub-group 265\u2009\ub1\u20091.54 (19) vs 271\u2009\ub1\u20091.38 (11); p\u2009= \u20090.008). Conclusions Our study suggests that miR-146a rs2910164 polymorphism might not be associated with PE susceptibility, cytokines or related features. However, the miR-146a GC/CC genotype might reduce susceptibility to severe PE, which might be further influenced by the presence of co-morbid HIV infection among pregnant women on HAART. This variant genotype may also be associated with reduced circulating IL-2 levels and thus reduced pro-inflammatory response in normotensive women, which may be further influenced by the presence of HIV infection and HAART

Sirtuin 1 rs1467568 and rs7895833 in South African Indians with early-onset coronary artery disease

BACKGROUND : Sirtuin 1 (SIRT1), a class III histone deacetylase, has been identified as a candidate molecule affecting the epigenetic mechanisms of cardiovascular disease (CVD). Previous studies have shown that some SIRT1 single-nucleotide polymorphisms (SNPs) are associated with body mass index, diabetes, blood pressure, cholesterol metabolism and coronary artery calcification. We investigated two A>G SIRT1 SNPs, rs1467568 and rs7895833, in young South African (SA) Indians with coronary artery disease (CAD) and compared them to Indian and black controls. METHODS : For rs1467568, a total of 287 subjects were recruited into this study (104 CAD patients, 99 age-, gender- and race-matched controls, and 84 age- and gender-matched black controls). For rs7895833, a total of 281 subjects were recruited into this study (100 CAD patients, 99 age-, gender- and race-matched controls, and 82 age- and gender-matched black controls). All patients were male, of Indian ethnicity, stable CAD confirmed on angiography, mean age 37.5 years; range 24–45. All subjects were genotyped using TaqMan SNP genotyping assays. RESULTS : The variant allele for both SNPs was found at a higher frequency in the total Indian group compared to the total black population (rs1467568: 41 vs 18.5%, respectively, p < 0.0001, OR = 3.190, 95% CI: 2.058–40943; and rs7895833: 41 vs 22%, respectively, p < 0.0001, OR = 2.466, 95% CI: 1.620– 3.755). Indian controls presented with a higher frequency for both SNPs compared to black controls (rs1467568: 40 vs 18.5%, respectively, p < 0.0001, OR = 2.996, 95% CI: 1.850– 4.853; and rs7895833: 41 vs 22%, respectively, p < 0.0001, OR = 2.513, 95% CI: 1.578–4.004). No difference was seen in the distribution of both SNPs between CAD patients and either control group. We did not observe any association between the SNPs and clinical parameters in CAD patients and controls. CONCLUSION : Both SNP variant alleles occurred more frequently in SA Indians than in SA blacks. A larger study group and further analysis is required to assess whether these SIRT1 SNPs may serve as risk factors that contribute to Indians developing early-onset CAD.The National Research Foundation (NRF) for a scholarship and UKZN (College of Health Sciences).www.cvja.co.zaam2016Physiolog

Pro-inflammatory cytokine levels in HIV infected and uninfected pregnant women with and without pre-eclampsia

DRRM  cytokine analysi

Clinical characteristics of participants.

<p>Clinical characteristics of participants.</p

Comparative analysis of cytokine perturbations by groups.

<p>Comparative analysis of cytokine perturbations by groups.</p

Quantitative evaluation of cytokines.

<p>Quantitative evaluation of cytokines.</p

MiR-146a G/C rs2910164 variation in South African Indian and Caucasian patients with psoriatic arthritis

Abstract Background Psoriasis and psoriatic arthritis (PsA) are inflammatory associated autoimmune disorders. MicroRNA (miR)-146a plays a crucial role in regulating inflammation. A single nucleotide polymorphism in the miR-146a gene (rs2910164), aberrantly alters its gene expression and linked with the pathogenesis of several disorders, including psoriasis and PsA. In South Africa, psoriasis and PsA are extremely rare in the indigenous African population and most common in both the Indian and Caucasian population. The aim of this study was to investigate whether the miR-146a rs2910164 contributes towards psoriasis and PsA development in South African Indian and Caucasian patients. Methods South African Indian (n = 84) and Caucasian (n = 32) PsA patients (total n = 116) and healthy control subjects (Indian: n = 62 and Caucasian: n = 38; total n = 100) were recruited in the study. DNA was extracted from whole blood taken from all subjects, and genotyped for the miR-146a rs2910164 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Data for laboratory parameters were obtained from pathology reports. The consulting rheumatologist collected all other clinical data. Results Unstratified data (Caucasians + Indians) : A significant decrease in C-reactive protein (CRP) levels in PsA patients was observed (CRP monitored at inclusion vs. after 6 months of treatment) (18.95 ± 2.81 mg/L vs. 9.68 ± 1.32 mg/L, p = 0.0011). The miR-146a rs2910164 variant C-allele frequency in PsA patients was significantly higher vs. healthy controls (35.78% vs. 26% respectively, p = 0.0295, OR = 1.59 95% CI 1.05–2.40). Stratified data (Indians) : The variant C-allele frequency in Indian PsA patients was significantly higher vs. healthy Indian controls (35.71% vs. 22.58%, p = 0.0200, OR = 1.91 95% CI 1.13–3.22). Stratified data (Caucasians) : The variant C-allele frequency distribution between Caucasian PsA patients and healthy Caucasian controls was similar. Conclusion The rs2910164 variant C-allele may play a role in the progression of PsA in the South African Indian population. The main limitation in this study was the small sample size in the case-control cohorts, with a low overall statistical power (post-hoc power analysis = 19%)