The heat stress (HS) induced by high temperatures can result in oxidative damage to muscles, thereby compromising both muscle growth and immune function within the organism. Mitophagy serves as a pivotal pathway in alleviating excessive ROS production and subsequent oxidative damage. However, the potential role of epigallocatechin-3-gallate (EGCG), a natural antioxidant found in tea, in mitophagy under HS remains unexplored. Here, we present evidence of EGCG mitigating the oxidative–redox imbalance in porcine skeletal muscles induced by HS involving the antioxidant enzyme system mediated by the Keap1/Nrf2 pathway and mitophagy mediated by the PINK1/Parkin pathway. Importantly, we identified phosphate mutase 5 (PGAM5) for the first time as a key protein modulated by EGCG under HS conditions, regulating mitophagy. Inhibition of PGAM5 significantly attenuated the activation of mitophagy by EGCG. Molecular docking and dynamics simulations further suggested that EGCG directly binds to Keap1, disrupting the Keap1–PGAM5 protein interaction and thus promoting the release of PGAM5 and subsequently activating mitophagy. In summary, this study represents the first discovery of EGCG directly targeting Keap1/PGAM5-mediated mitophagy, which serves as a potential functional supplement for regulating the antioxidant capacity in pigs.

中文翻译：

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EGCG 通过 Keap1/PGAM5 复合物介导的线粒体自噬减轻热应激猪骨骼肌氧化损伤


高温诱导的热应激 （HS） 会导致肌肉氧化损伤，从而损害生物体内的肌肉生长和免疫功能。线粒体自噬是缓解 ROS 过量产生和随后的氧化损伤的关键途径。然而，表没食子儿茶素-3-没食子儿茶素-3-没食子酸酯 （EGCG） 是一种在茶中发现的天然抗氧化剂，在 HS 下线粒体自噬中的潜在作用仍未得到探索。在这里，我们提供了 EGCG 减轻 HS 诱导的猪骨骼肌氧化还原失衡的证据，涉及由 Keap1/Nrf2 通路介导的抗氧化酶系统和由 PINK1/Parkin 通路介导的线粒体自噬。重要的是，我们首次确定磷酸盐变位酶 5 （PGAM5） 是 HS 条件下受 EGCG 调节的关键蛋白，可调节线粒体自噬。抑制 PGAM5 显着减弱了 EGCG 对线粒体自噬的激活。分子对接和动力学模拟进一步表明，EGCG 直接与 Keap1 结合，破坏 Keap1-PGAM5 蛋白相互作用，从而促进 PGAM5 的释放，随后激活线粒体自噬。综上所述，本研究首次发现 EGCG 直接靶向 Keap1/PGAM5 介导的线粒体自噬，可作为调节猪抗氧化能力的潜在功能补充剂。