Screening And Identification Of Genetic Risk Factors For Coronary Artery Disease In Oxidative Stress And Lipid-associated Pathways

Objective To investigate whether single nucleotide polymorphisms(SNPs)in thioredoxin-interacting protein(TXNIP)gene and lipid-associated loci were genetic risk factors for coronary artery disease(CAD)in the Chinese Han population.Method(1)In a two-stage case-control study with a total of 1818 CAD patients and 1963 controls,three SNPs in TXNIP were genotyped by high-resolution melting(HRM)analyses.TXNIP mRNA expression and methylation levels at cg19693031 in leucocytes were detected by reverse-transcription quantitative PCR and pyrosequencing analyses,respectively.Plasma levels of TXNIP and malondialdehyde(MDA)were determined by ELISA and thiobarbituric acid reactive substances assays,respectively.The severity of coronary atherosclerosis was assessed by frequencies of left main trunk disease,vessel scores,and modified Gensini scores.The gene-environment interactions in CAD risk were appraised by subgroup,multifactor dimensionality reduction(MDR),and classification and regression tree(CART)analyses.(2)In 1100 CAD patients and 1069 controls,six lipid-associated SNPs were genotyped by HRM analyses.The severity of coronary atherosclerosis was assessed by vessel scores and modified Gensini scores.The genetic risk scores(GRS)were calculated by merging the risk alleles of significant loci(HNF1A rs 1169288,MADD-FOLH1 rs7395662,and NAT2 rs1495741)weighted by their effect sizes.Expression quantitative trait loci(eQTL)analyses were performed by combining the genotype and expression data from HapMap release 3.3,1000 Genomes Browser and ArrayExpress databases.Results(1)In discovery,replication,and their merged sets,the variant genotypes of SNPs rs7212(OR = 1.26,P = 0.001)and rs7211(OR = 1.23,P = 0.005)were significantly associated with CAD risk under a dominant model.In haplotype analyses,compared with the reference haplotype,haplotype "G-T" had a 1.22-fold increased risk of CAD(P = 0.003).We also observed the cumulative effects of SNPs rs7212 and rs7211 on CAD risk and the severity of coronary atherosclerosis.Moreover,the gene-environment interactions among the variant genotypes of SNP rs7212,smoking habit,alcohol drinking habit and history of type ? diabetes were associated with a 3,70-fold increased risk of CAD(P<0.001).Subsequent genotype-phenotype correlation analyses further observed the significant effects of SNP rs7212 on TXNIP mRNA expression,plasma TXNIP and MDA levels.(2)In single-locus analyses,the minor allele C of HNF1A rs1169288 was positively associated with total cholesterol(TC)levels(? = 0.060,P = 0.001),CAD risk(OR=1.18,P=0.006),vessel scores(P = 0.002),and modified Gensini scores(? = 0.113,P=0.002);the minor allele A of MADD-FOLH1 rs7395662 was correlated with decreased high-density lipoprotein cholesterol(HDL-c)levels(? =-0.024,P = 0.007)and increased CAD risk(OR = 1.20,P = 0.002).The GRS,consisting of three risk loci,was found to be associated with TC levels(?= 0.033,P<0.001),HDL-c levels(?=-0.013,P = 0.004),CAD risk(P<0.001),and modified Gensini scores(?= 0.028,P = 0.003).Subsequent eQTL analyses revealed significant effects of rs1169288 and rs7395662 on HNF1A and MADD mRNA expression,respectively.Conclusion(1)TXNIP SNPs may individually and cumulatively affect CAD risk through a possible mechanism of regulating TXNIP expression and gene-environment interactions.(2)Lipid-associated loci may jointly contribute to CAD risk and the severity of coronary atherosclerosis.