Follicular fluid meiosis-activating sterol (FF-MAS) is a small molecule compound found in FF, named for its ability to induce oocyte resumption of meiosis. Granulosa cells (GCs) within the follicle are typically located in a hypoxic environment under physiologic conditions due to limited vascular distribution. Previous research suggests that hypoxia-induced cell cycle arrest and apoptosis in GCs may be crucial triggering factors in porcine follicular atresia. However, the impact of FF-MAS on GCs within follicles has not been explored so far. In this study, we uncovered a novel role of FF-MAS in facilitating GC survival under hypoxic conditions by inhibiting STAT4 expression. We found that STAT4 expression was upregulated in porcine GCs exposed to 1% O2. Both gain and loss of function assays confirmed that STAT4 was required for cell apoptosis under hypoxia conditions, and that the GC apoptosis caused by hypoxia was markedly attenuated following FF-MAS treatment through inhibition of STAT4 expression. Correlation analysis in vivo revealed that GC apoptosis was associated with increased STAT4 expression, while the FF-MAS content in follicular fluid was negatively correlated with STAT4 mRNA levels and cell apoptosis. These findings elucidate a novel role of FF-MAS-mediated protection of GCs by inhibiting STAT4 expression under hypoxia, which might contribute to the mechanistic understanding of follicular development.

中文翻译：

---

滤泡液减数分裂激活甾醇通过抑制 STAT4 表达来防止猪卵巢颗粒细胞缺氧诱导的细胞凋亡


滤泡液减数分裂激活甾醇 （FF-MAS） 是一种在 FF 中发现的小分子化合物，因其诱导卵母细胞恢复减数分裂的能力而得名。由于血管分布有限，卵泡内的颗粒细胞 （GCs） 在生理条件下通常位于缺氧环境中。先前的研究表明，缺氧诱导的 GC 细胞周期停滞和凋亡可能是猪滤泡闭锁的关键触发因素。然而，到目前为止，FF-MAS 对卵泡内 GC 的影响尚未得到探索。在这项研究中，我们发现了 FF-MAS 通过抑制 STAT4 表达在低氧条件下促进 GC 存活的新作用。我们发现 STAT4 表达在暴露于 1% O 2 的猪 GCs 中上调。功能获得和丧失试验均证实，在缺氧条件下细胞凋亡需要 STAT4，并且在 FF-MAS 处理后通过抑制 STAT4 表达显着减弱了缺氧引起的 GC 细胞凋亡。体内相关性分析显示，GC 细胞凋亡与 STAT4 表达增加相关，而滤泡液中 FF-MAS 含量与 STAT4 mRNA 水平和细胞凋亡呈负相关。这些发现阐明了 FF-MAS 通过抑制缺氧下 STAT4 表达对 GCs 的保护的新作用，这可能有助于对卵泡发育的机制理解。