Epigenomic Landscape of Human Cumulus Cells in Premature Ovarian Insufficiency Using Single‐Base Resolution Methylome and Hydroxymethylome

ABSTRACT Premature ovarian insufficiency (POI) has recently been reported to be linked with epigenetic changes. Previous studies have focused on the regulation of individual genes associated with ovarian function through single‐gene epigenetic variations; however, there is a deficiency in the comprehensive comprehension of the epigenetic profile for POI. Therefore, we conducted a multi‐omics study integrating methylation, hydroxymethylation and transcriptome sequencing analyses in cumulus cells from women with POI and their matched controls. Our data revealed significant global increases in methylation and hydroxymethylation levels in POI patients. We observed a predominance of hypermethylated and hyperhydroxymethylated regions across the genome, with methylation in gene bodies negatively correlating with gene expression, especially in promoter regions. Subsequent experimental validation was performed to confirm the involvement of candidate genes (EGR1, EGR2 and DLX5) in ovarian steroid hormone synthesis. Interestingly, our findings indicate that these epigenetic modifications are associated with genes implicated in POI, ovarian function and the epigenetic age clock. This comprehensive epigenetic profile underscores the potential for identifying novel biomarkers and therapeutic targets for POI by unravelling the complex interplay between DNA epigenetics and ovarian function.