Altered m(6)A modification is involved in up‐regulated expression of FOXO3 in luteinized granulosa cells of non‐obese polycystic ovary syndrome patients

The pathophysiology of polycystic ovary syndrome (PCOS) is characterized by granulosa cell (GC) dysfunction. m(6)A modification affects GC function in patients with premature ovarian insufficiency (POI), but the role of m(6)A modification in PCOS is unknown. The purpose of the prospective comparative study was to analyse the m(6)A profile of the luteinized GCs from normovulatory women and non‐obese PCOS patients following controlled ovarian hyperstimulation. RNA m(6)A methylation levels were measured by m(6)A quantification assay in the luteinized GCs of the controls and PCOS patients. Then, m(6)A profiles were analysed by methylated RNA immunoprecipitation sequencing (MeRIP‐seq). We reported that the m(6)A level was increased in the luteinized GCs of PCOS patients. Comparative analysis revealed differences between the m(6)A profiles from the luteinized GC of the controls and PCOS patients. We identified FOXO3 mRNA with reduced m(6)A modification in the luteinized GCs of PCOS patients. Selectively knocking down m(6)A methyltransferases or demethylases altered expression of FOXO3 in the luteinized GCs from the controls, but did not in PCOS patients. These suggested an absence of m(6)A‐mediated transcription of FOXO3 in the luteinized GCs of PCOS patients. Furthermore, we demonstrated that the involvement of m(6)A in the stability of the FOXO3 mRNA that is regulated via a putative methylation site in the 3’‐UTR only in the luteinized GCs of the controls. In summary, our findings showed that altered m(6)A modification was involved in up‐regulated expression of FOXO3 mRNA in the luteinized GCs from non‐obese PCOS patients following controlled ovarian hyperstimulation.