DNA Methylation and SNPs of ABCA1 Gene Promoter Affect Gene Expression and Involve in the Pathological Mechanism of Ischemic Stroke

Abstract

ATP binding cassette subfamily A1 (ABCA1) is a key protein in the formation of mature high density lipoprotein (HDL), which plays a crucial role in atherosclerosis. Accumulating evidence has shown that the expression levels of the ABCA1 gene are upregulated in ischemic stroke (IS) patients. However, the mechanism remains elusive. We hypothesized that DNA methylation and SNPs of ABCA1 gene promoter affect the expression levels of ABCA1 gene and involve in the pathological mechanism of IS. 100 patients with IS and 100 healthy controls were enrolled in the present study. Initially, the mRNA expression levels of ABCA1 gene were examined by qPCR and the methylation levels was detected by MethyTarget sequencing. Then, rs1800976, rs1800977, rs2246298, rs2437817, rs2740483, rs539621172 in promoter region of ABCA1 gene were selected for genotyping. Finally, the relationship between the methylation of ABCA1 gene and gene expression was verified by constructing THP-1 foam cell model. The mRNA expression levels of ABCA1 gene in the IS group were significantly higher than those in controls (P<0.05). 17 CpG sites in the promoter of ABCA1 gene were analyzed and the DNA methylation levels of CpG1, CpG7 and CpG15 sites in IS group was significantly lower than control group (P<0.05). Rs2740483, rs1800977 and rs2437817 were significantly correlated with CpG1. Rs1800977 was significantly correlated with CpG3. In summary, DNA methylation and rs2740483, rs1800977, rs2437817 of ABCA1 gene promoter affect the expression levels of ABCA1 gene, change the clearance rate of intracellular lipids, and participate in the pathogenesis of IS.