Lipopolysaccharide (LPS) is an inhibitory factor that causes hormonal imbalance and subsequently affects ovarian function and fertility in mammals. Previous studies have shown that the exposure of granulosa cells (GC) to LPS leads to steroidogenesis dysfunction. However, the effects of LPS on the viability of GC remain largely unclear. In the present study, we aimed to address this question and unveil the underlying molecular mechanisms using cultured porcine GC. Results showed that GC proliferation and tumor necrosis factor α (TNFα) secretion were significantly increased after exposure to LPS, and these effects were completely reversed by blocking the TNFα sheddase, ADAM17. Moreover, GC proliferation induced by LPS was mimicked by treatment with recombinant TNFα. In addition, SerpinE1 and SerpinB2 expression levels increased in GC after treatment with LPS or recombinant TNFα, whereas blocking the Erk1/2 pathway completely abolished these effects and also inhibited GC proliferation. Further, consistent with the effects of blocking the Erk1/2 pathway, cell proliferation was completely inhibited by knocking down SerpinE1 or SerpinB2 in the presence of LPS or recombinant TNFα. Mitochondrial membrane potential (MMP) polarization in GC was increased by LPS or recombinant TNFα treatment, and these changes were completely negated by Erk1/2 inhibition, but not by SerpinE1 or SerpinB2 knockdown. Taken together, these results suggested that the TNFα-mediated upregulation of SerpinE1 and SerpinB2, through activation of the Erk1/2 pathway plays a crucial role in LPS-stimulated GC proliferation, and the increase in GC MMP may synergistically influence this process.

脂多糖 (LPS) 是一种抑制因子，会导致激素失衡，进而影响哺乳动物的卵巢功能和生育能力。先前的研究表明，颗粒细胞 (GC) 暴露于 LPS 会导致类固醇生成功能障碍。然而，LPS 对 GC 活力的影响在很大程度上仍不清楚。在本研究中，我们旨在解决这个问题，并使用培养的猪 GC 揭示潜在的分子机制。结果表明，暴露于LPS后GC增殖和肿瘤坏死因子α（TNFα）分泌显着增加，并且通过阻断TNFα脱落酶ADAM17可以完全逆转这些影响。此外，用重组 TNFα 处理模拟了 LPS 诱导的 GC 增殖。此外，用 LPS 或重组 TNFα 处理后，GC 中 SerpinE1 和 SerpinB2 的表达水平增加，而阻断 Erk1/2 通路完全消除了这些影响，也抑制了 GC 增殖。此外，与阻断 Erk1/2 通路的作用一致，在 LPS 或重组 TNFα 存在下，通过敲低 SerpinE1 或 SerpinB2 完全抑制细胞增殖。LPS 或重组 TNFα 处理增加了 GC 中的线粒体膜电位 (MMP) 极化，并且这些变化被 Erk1/2 抑制完全抵消，但不会被 SerpinE1 或 SerpinB2 敲低。总之，这些结果表明 TNFα 介导的 SerpinE1 和 SerpinB2 上调，通过激活 Erk1/2 通路在 LPS 刺激的 GC 增殖中起关键作用，