Genome-Wide Identification of Epigenetic Hotspots Potentially Related to Cardiovascular Risk in Adult Women after a Complicated Pregnancy

Abstract

Background: The physiological demands of pregnancy on the maternal cardiovascular system can catapult women into a metabolic syndrome that predisposes to atherosclerosis in later life. We sought to identify the nature of the epigenomic changes associated with the increased cardiovascular disease (CVD) risk in adult women following pre-eclampsia.

Findings: We assessed the genome wide epigenetic profile by methyl-C sequencing of monozygotic parous twin sister pairs discordant for a severe variant of pre-eclampsia. In the adult twin sisters at risk for CVD as a consequence of a complicated pregnancy, a set of 12 differentially methylated regions with at least 50% difference in methylation percentage and the same directional change was found to be shared between the affected twin sisters and significantly different compared to their unaffected monozygous sisters.

Conclusion: The current epigenetic marker set will permit targeted analysis of differentially methylated regions potentially related to CVD risk in large cohorts of adult women following complicated pregnancies.

Fig 1. Scatter plot of differentially methylated regions (DMRs) with significant difference between adult monozygotic twins sisters discordant for severe pre-eclampsia and subsequent CVD risk.

DMRs were identified by genome-wide methylC-sequencing followed by Bismark analysis.

Fig 2

By targeted methyl-C DNA sequencing (principle explained in A), DMR1 (see Table 3) was analyzed. Within the 80 bp region analyzed (B), 2 patterns were found after bisulfite sequencing. Strands were either completely unmethylated (B1) or hemimethylated at 4 sites presenting as heterozygous calls (B1+B2). For comparison, the converted upper strand is shown (B3). The unaffected twins showed hemimethylation of 4 (boxes) out of 16 methylation sensitive C nucleotides (C1+C2) and hypomethylation (loss of methylation) in affected twins (C3+C4). Open circle: unmethylated, closed circle: methylated.