SIRT3 attenuates AGEs-induced senescence in human granulosa cells through enhancing mitophagy

Age-related decreases in follicle numbers and oocyte quality are major contributors to the decline in female fertility, which is associated with increased infertility rates. Emerging evidence suggests that targeting granulosa cell senescence could delay ovarian aging and depletion of the ovarian reserve, highlighting the potential for therapeutic interventions focused on granulosa cells. Advanced glycation end products (AGEs) accumulate with age and result in oxidative stress in the follicular microenvironment, but their direct impact on human granulosa cell (hGC) senescence and the fundamental processes are still mostly unknown. In this study, we found that AGEs treatment significantly exacerbated hGC senescence, impaired mitochondrial function, and suppressed mitophagy in a concentration-dependent manner. Importantly, these deficits were lessened by urolithin A-induced mitophagy activation, whereas Cyclosporine A-induced mitophagy inhibition had the reverse consequences. In addition, silencing Sirtuin 3 (SIRT3) or PINK1 further aggravated these adverse effects, while SIRT3 overexpression attenuated senescence and restored mitochondrial function by enhancing mitophagy. Furthermore, SIRT3 overexpression promoted the synthesis of estradiol-17β and progesterone, key hormones for ovarian function. Our findings demonstrated that AGEs induced hGC senescence by disrupting mitochondrial function and inhibiting mitophagy, with SIRT3 playing a protective role. Enhancing mitophagy by targeting SIRT3 may be a promising treatment approach to counteract age-related declines in female fertility.