Neddylation inhibition alleviates polycystic ovary syndrome by regulating granulosa cell function and androgen synthesis

Polycystic ovary syndrome (PCOS) is a common and complex endocrine and metabolic disorder whose etiology has not yet been fully elucidated. Emerging research has revealed an association between PCOS pathogenesis and post-translational modifications of proteins. However, the effect of neddylation on PCOS pathogenesis has not been investigated. In this study, key proteins of the neddylation pathway (Nedd8, neddylation-activating enzyme (NAE), and Cullin-1/2/3) were significantly upregulated in the granulosa cells of patients with PCOS; this was accompanied by enhanced apoptosis (increased Bax and Caspase-3, decreased Bcl-2) and elevated expression of the androgen synthesis-related proteins, namely: androgen receptor (AR) and Cytochrome P450 Family 17 Subfamily A Member 1(CYP17A1). In the in vitro DHT-induced PCOS KGN cell model, key neddylation pathway proteins (Nedd8, NAE, and Cullin-1) were upregulated. Overexpression of Nedd8 and inhibition of neddylation by MLN4924 promoted apoptosis. However, inhibition of neddylation by MLN4924 reversed AR/CYP17A1 protein expression. In a rat model of PCOS, MLN4924 treatment significantly suppressed the expression of Nedd8, NAE, and Cullin-1/2/3 in the ovarian tissue, restored estrous cycles, alleviated ovarian morphological abnormalities (characterized by increased corpora lutea and reduced cystic follicles), and decreased serum testosterone and LH levels. MLN4924 significantly promoted ovarian granulosa cell apoptosis, but reduced the expression of androgen synthesis-related proteins. Together, these findings indicate the unrecognized role of neddylation in PCOS, while highlighting that MLN4924 represents a potential therapeutic approach for PCOS treatment.