Targeting NAT10 alleviates granulosa cells oxidative stress and follicular atresia by disrupting ac4C acetylation of Tnc

Follicular atresia mediated by programmed granulosa cells (GCs) death directly contributes to ovarian dysfunction-related disorders and infertility or subfertility in mammals. N-acetyltransferase 10 (NAT10)-catalyzed N4-acetylcytidine (ac4C) modification has been identified to drive multiple biological processes, but its function in GCs death and follicular atresia is unclear. In this study, we found that a significant increase in both the ac4C RNA level and NAT10 expression in atretic follicle. Functionally, NAT10 promotes oxidative stress by inhibiting the mitophagy of GCs in vitro. Mechanistically, we identified Tnc mRNA, an important extracellular matrix glycoprotein, as a direct target of NAT10-catalyzed ac4C modification. This modification enhances the mRNA stability of Tnc, inhibits the mitophagy and promotes the oxidative stress of GCs, thereby contributing to follicular atresia progression. Additionally, we revealed that Tnc directly binds with Parkin and accelerates the ubiquitination and proteasomal degradation of Parkin, leading to inhibition of Parkin-mediated mitophagy pathway. Notably, Remodelin, a specific NAT10 inhibitor, promotes the mitophagy and inhibits the oxidative stress of GCs in vitro, and hinders follicular atresia and ameliorates impaired reproductive efficiency caused by oxidative stress of GCs in vivo through NAT10-ac4C-Tnc pathway. These findings suggested that NAT10 drives follicular atresia progression via Tnc mRNA stability regulation, and Remodelin could be a promising therapeutic candidate for targeting NAT10 in follicular atresia and infertility or subfertility treatment.