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Atherosclerosis and aneurysm of the aorta are relatively common pathological conditions that remain asymptomatic for a long period of time and have life-threatening and disabling complications. DNA methylation profiling in several regions (a dilated area, a nondilated area, and an atherosclerotic plaque) of the ascending aorta was carried out in patients with aortic aneurysm. DNA methylation was analyzed by reduced representation bisulfite sequencing (RRBS). Differences in methylation level between dilated and normal aortic tissues were detected for two CpG sites of the NR2F1-AS1 gene (|Δβ| > 0.2 and FDR < 0.05). In total, 586/480 differentially methylated CpG sites (DMSs) were identified by comparing atherosclerotic plaque samples with dilated/normal aortic tissues; 323/234 of the DMSs were hypermethylated and 263/246 were hypomethylated in atherosclerotic plaques. Most DMSs were in introns and intergenic regions; 88.2% of the DMSs were in the binding sites of transcription factors, among which ZNf263, ZFP148, PATZ1, NRF1, TCF12, and EGR1 play a role in the pathogenesis of atherosclerosis of various arteries and ELK1, ETS1, and KLF15 play a role in aortic aneurysms. Sixteen DMSs were found in the regions of the genes CMIP, RPH3AL, XRCC1, GATA5, EXD3, KCNC2, HIVEP3, ADCY9, CDCP2, FOLR1, WT1, MGMT, GAS2, CA1, PRSS16, and ANK3, whose protein products are involved in both aortic dissection and atherosclerosis in various arterial circulation regions. The protein products of the genes are involved in a wide range of biological processes, including mesenchyme development (GO:0060485; FOLR1, WT1, GATA5, HIVEP3, and KCNC2) and positive regulation of DNA metabolic processes (GO:0051054; MGMT, WT1, and XRCC1).

The status of DNA methylation in the human genome changes during the pathogenesis of common diseases and acts as a predictor of life expectancy. Therefore, it is of interest to investigate the methylation level of regulatory regions of genes responsible for general biological processes that are potentially significant for the development of age-associated diseases. Among them there are genes encoding proteins of DNA repair system, which are characterized by pleiotropic effects. Here, results of the targeted methylation analysis of two regions of the human genome (the promoter of the MLH1 gene and the enhancer near the ATM gene) in different tissues of patients with carotid atherosclerosis are present. Analysis of the methylation profiles of studied genes in various tissues of the same individuals demonstrated marked differences between leukocytes and tissues of the vascular wall. Differences in methylation levels between normal and atherosclerotic tissues of the carotid arteries were revealed only for two studied CpG sites (chr11:108089866 and chr11:108090020, GRCh37/hg19 assembly) in the ATM gene. Based on this, we can assume the involvement of ATM in the development of atherosclerosis. "Overload" of the studied regions with transcription factor binding sites (according to ReMapp2022 data) indicate that the tissue-specific nature of methylation of the regulatory regions of the MLH1 and ATM may be associated with expression levels of these genes in a particular tissue. It has been shown that inter-individual differences in the methylation levels of CpG sites are associated with sufficiently distant nucleotide substitutions. [ABSTRACT FROM AUTHOR]