Nuclear receptor coactivator 4 linked to follicular dysplasia in polycystic ovary syndrome: A key regulator that aggravates ovarian granulosa cells ferritinophagy and ferroptosis

Ferroptosis is a type of cell death caused by iron-dependent lipid peroxidation and excessive production of reactive oxygen species (ROS). Hyperandrogen exposure can induce ovarian ferroptosis in polycystic ovary syndrome (PCOS). However, there is not enough direct evidence regarding ovarian ferroptosis in PCOS to prove the role of ferroptosis in PCOS and the underlying mechanism. Nuclear receptor coactivator 4 (NCOA4) expression in ovarian granulosa cells and its mechanism of mediating ferroptosis have not been studied. In this study, we aimed to investigate how iron overload in ovarian granulosa cells and hyperandrogen exposure-induced ferroptosis affect ovarian development in a PCOS model. Increased ferroptosis was observed in hyperandrogenic mice with PCOS and in 5α-dihydrotestosterone (DHT)-induced primary granulosa cells. Iron deposition increased significantly, followed by increased cellular Fe²⁺ concentration, whereas ROS accumulation, malondialdehyde (MDA), glutathione (GSH), and the glutathione/oxidized glutathione (GSH/GSSG) ratio decreased. NCOA4 and transferrin receptor expression increased; however, ferritin heavy chain 1 expression decreased in ovarian tissues. Androgen receptor and NCOA4 showed increased colocalization in the ovarian granulosa cell layer. Notably, DHT induced ferroptosis by activating NOCA4-dependent ferritin autophagy. However, deferoxamine mesylate inhibited ferroptosis in the ovarian granulosa mice cells, ameliorating the PCOS phenotype. Steroid hormone biosynthesis, arachidonic acid metabolism, and unsaturated fatty acid pathways were most significantly affected, providing a reference for PCOS diagnosis and treatment and corresponding drug development.