Epigenome Mapping of Human Normal Purified Hepatocytes: Personal Epigenome Variation and Genome–Epigenome Correlation

AIM: The aim of this study was to reveal the epigenome landscape of human normal hepatocytes. MATERIALS & METHODS: Cells purified from partial hepatectomy specimens of Japanese patients were subjected to whole-genome bisulfite sequencing using postbisulfite adaptor tagging, chromatin immunoprecipitation sequencing, RNA sequencing and whole-genome sequencing. RESULTS: CHG and CHH methylations were inversely associated with gene expression. Histone modification profiles of personal differentially methylated regions (pDMRs) differed considerably among samples. pDMRs were observed around the transcription start sites of genes whose expression is reportedly regulated by CpG methylation. pDMRs were frequently observed in the vicinity of single-nucleotide variations and insertions/deletions. CONCLUSION: Genetic variations may induce epigenetic variations, generating individual differences in the phenotypes of normal hepatocytes through variations in expression.