To explore the epigenetic mechanism of deoxyribonucleic acid (DNA) damage induced by vinyl chloride (VC), we studied the micronuclei of peripheral blood lymphocytes in 193 subjects (92 in a VC exposure group employed in a chlorine-alkali plant; 101 in a control group employed in a power plant) and selected three pairs from the subjects (exposed and control) for whole-genome bisulfite sequencing (WGBS). The results showed that the rate of micronucleus formation in the VC exposure group was higher than that of control group (6.05 ± 3.28‰ vs. 2.01 ± 1.79‰). A total of 9534 differentially methylated regions (DMRs) were identified by WGBS, of which 4816 were hypomethylated and 4718 were hypermethylated. The Kyoto encyclopedia of genes and genomes (KEGG) pathway and gene ontology (GO) analyses showed the top three KEGG pathways were cancer , neuroactive ligand-receptor interaction, and axon guidance, and the top three GO-BP pathways enriched were multicellular organismal process, developmental process, and anatomical structure development. In the most enriched DMR pathway (pathways in cancer), we found that BCL2, TJP2, TAOK1, PFKFB3, LIPI, and LIPH were hypermethylated, and the methylation levels of BNIP1 and GRPEL2 were decreased. The methylation of differentially methylated genes (DMGs) mentioned above were verified by methylation-specific PCR (MSP) and agarose gel electrophoresis (AGE) in 50 pairs of subjects, where the coincidence rate was 60-100%. In conclusion, the epigenetic perturbations of specific DMGs (BCL2, TJP2, TAOK1, PFKFB3, LIPI, LIPH, BNIP1, and GRPEL2) may be associated with DNA damage from vinyl chloride exposure.
Keywords: DNA methylation; differentially methylated regions; vinyl chloride; whole-genome bisulfite sequencing.