Changes Of Genome-wide DNA Methylation In Peripheral Blood Nucleated Cells Of Workers Exposed To Vinyl Chloride

Objectives:WGBS was performed on the DNA of peripheral blood nucleated cells of workers exposed to vinyl chloride occupationally,so as to map the whole genome DNA methylation change spectrum,screen out DMRs and DMGs,and explore the early biological markers of carcinogenesis of vinyl chloride and its epigenetic mechanism.Methods:Physical examination data and occupational exposure data of employees of a chlorinealkali plant(exposure group)and a power plant(control group)in Shandong province were collected,and 5ml peripheral blood at elbow was collected.According to the accumulated exposure dose and micronucleus test results,3 subjects were selected in the exposed group and the control group respectively,and the DNA of peripheral blood nucleated cells was sequenced through WGBS to detect the level of whole-genome DNA methylation,and to find out DMRs and DMGs.KEGG pathway analysis and gene-ontology analysis were performed on the sequencing results,and methylation specific PCR and agarose gel electrophoresis were used to verify the methylation level of genes in the peripheral blood nucleated cells of 50 randomly selected subjects in the exposed group and the control group.Results:Compared with the control group,a total of 9534 DMRs were identified by WGBS in the whole genome,among which 4816 DMRs were hypomethylated and 4718 DMRs were hypermethylated.There were 1333 DMGs,among which,apoptosis related genes included BCL2,MADD,TJP2,AEN,TAOK1,BNIP1,and DNA damage repair related genes included LIPH,NBN,LIPI,ATM,PFKFB3,GRPEL2,cell cycle-related genes included LIPH,LIPI,PFKFB3,GRPEL2 and etc.,these genes were related to basic physiological processes.Gene ontology analysis showed that the genes were mainly distributed at the junction between cells,extracellular region,membrane and organelle,affected protein kinase activity,phospholipase activity,catalytic activity,receptor activity and structural molecule activity,involved cell death and its regulation,programmed cell death and its regulation,apoptosis regulation of DNA damage repair,cell proliferation regulation,autophagy regulation and other biological functional processes.KEGG pathway analysis showed that genes were enriched in cancer,rap1 signaling pathway,cAMP signaling pathway,hippo signaling pathway,cGMP-PKG signaling pathway.The methylation levels of BCL2,TJP2,TAOL1,LIPI,LIPH and PFKFB3 were increased,BNIP1 and GRPEL2 were decreased.Conclusions:The methylation level of genome-wide DNA in peripheral blood nucleated cells was increased due to vinyl chloride exposure,and the specific DMGs would be used as early biomarkers for vinyl chloride exposure.