Wang Zhe, Wei Quanwei, Geng He, Malyar Rahmani Mohammad, Berthier Tevanu, Shi Fangxiong
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Free Radic Biol Med. 2025 Jul 31. doi: 10.1016/j.freeradbiomed.2025.07.049.
Follicular atresia plays a significant role in the depletion of the ovarian reserve and the decline of overall ovarian function. Understanding its molecular mechanisms is essential to preventing ovarian aging and maintaining female reproductive health. Although NAD+ depletion is known to induce apoptosis in various cell types, the dynamic changes in NAD+ metabolism during follicular atresia remain unclear. Moreover, its specific impact on granulosa cells has not been fully elucidated. In this study, we examined the metabolic alterations of NAD+ during follicular atresia. We also explored the molecular mechanisms underlying granulosa cell apoptosis to provide a theoretical basis for developing novel therapeutic strategies to preserve female fertility. Using a well-established porcine model of follicular atresia, we observed a downregulation of key enzymes involved in NAD+ biosynthesis during follicular regression, accompanied by an increased progesterone to estradiol (P4/E2) ratio in the follicular fluid. In granulosa cells, reduced NAD+ levels and decreased NAD+/NADH ratios activated caspase-3 thereby triggering apoptosis. In a vitro model of granulosa cell apoptosis, we further demonstrated that NAD+ precursors can bypass the rate-limiting enzyme NAMPT but NMNAT1 remaines essential for effective NAD salvage. Deficiency of NMNAT1 compromised nuclear SIRT1 activity, leading to excessive p53 acetylation and the induction of apoptosis Additionally, pharmacological inhibition of NAMPT impaired mitochondrial SIRT3 activity, which enhanced p53-mediated apoptotic pathways. In conclusion, the NAD+ salvage pathway is crucial for regulating follicular atresia, NMNAT1 acts as a key regulator in granulosa cells within this pathway. It supports cell survival through SIRT1-mediated deacetylation of p53. These findings identify NMNAT1 as a potential therapeutic target to delay ovarian aging and preserve females fertility.
卵泡闭锁在卵巢储备的消耗和整体卵巢功能的衰退中起着重要作用。了解其分子机制对于预防卵巢衰老和维持女性生殖健康至关重要。尽管已知NAD+耗竭会诱导多种细胞类型发生凋亡，但卵泡闭锁过程中NAD+代谢的动态变化仍不清楚。此外，其对颗粒细胞的具体影响尚未完全阐明。在本研究中，我们研究了卵泡闭锁过程中NAD+的代谢变化。我们还探讨了颗粒细胞凋亡的分子机制，为开发保护女性生育能力的新治疗策略提供理论依据。利用成熟的猪卵泡闭锁模型，我们观察到卵泡退化过程中参与NAD+生物合成的关键酶下调，同时卵泡液中孕酮与雌二醇（P4/E2）的比值升高。在颗粒细胞中，NAD+水平降低和NAD+/NADH比值下降激活了半胱天冬酶-3，从而触发凋亡。在颗粒细胞凋亡的体外模型中，我们进一步证明NAD+前体可以绕过限速酶NAMPT，但NMNAT1对于有效的NAD挽救仍然至关重要。NMNAT1的缺乏损害了细胞核中SIRT1的活性，导致p53过度乙酰化并诱导凋亡。此外，对NAMPT的药理学抑制损害了线粒体中SIRT3的活性，增强了p53介导的凋亡途径。总之，NAD+挽救途径对于调节卵泡闭锁至关重要，NMNAT1在该途径中作为颗粒细胞的关键调节因子。它通过SIRT1介导的p53去乙酰化来支持细胞存活。这些发现确定NMNAT1是延缓卵巢衰老和维持女性生育能力的潜在治疗靶点。
