Abstract
Oxidative stress has been implicated in triggering granulosa cell (GC) death during follicular atresia. Recent studies suggested that follicle-stimulating hormone (FSH) has a pivotal role in protecting GCs from oxidative injury, although the exact mechanism remains largely unknown. Here, we report that FSH promotes GC survival by inhibiting oxidative stress-induced mitophagy. The loss of GC viability caused by oxidative stress was significantly reduced after FSH treatment, which was correlated with impaired activation of mitophagy upon oxidative stress. Compared with FSH treatment, blocking mitophagy displayed approximate preventive effect on oxidative stress-induced GC death, but FSH did not further restore viability of cells pretreated with mitophagy inhibitor. Importantly, FSH suppressed the induction of serine/threonine kinase PINK1 during oxidative stress. This inhibited the mitochondrial translocation of the E3 ligase Parkin, which is required for the subsequent clearance of mitochondria, and ultimately cell death via mitophagy. In addition, knocking down PINK1 using RNAi confirmed the role of the FSH-PINK1-Parkin-mitophagy pathway in regulating GC survival under oxidative conditions. These findings introduce a novel physiological function of FSH in protecting GCs against oxidative damage by targeting PINK1-Parkin-mediated mitophagy.