College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Biochimie. 2020 Mar;170:10-20. doi: 10.1016/j.biochi.2019.12.001. Epub 2019 Dec 9.
Oxidative stress leads to intestinal epithelial cells damage, which induces tight junction injury and systemic endogenous stress syndrome. The evidence suggests that SIRT1/PGC-1α pathway is closely associated with oxidative damage. However, the mechanism in protecting intestinal epithelial cells against oxidative stress dependant on autopahgy/mitophagy remains to be elucidated. In the current study, we investigated the functional role of SIRT1/PGC-1α pathway on regulation of autopahgy/mitophagy and tight junction protein expression underlying the oxidative dysfunction in porcine intestinal epithelial cells (IPEC-1). Results demonstrated that HO exposure caused high accumulation of ROS, with a decrease of mitochondrial membrane potential and an inhibition of the tight junction molecules in IPEC-1 cells. Also, COX IV mRNA expression and SIRT1/PGC-1α pathway were suppressed. Autophagy and PINK1/Parkin dependant-mitophagy were activated following HO treatment. Further research indicated that activation of SIRT1/PGC-1α pathway caused by specific activator SRT 1720 resulted in elevating autophagy/mitophagy related markers and SIRT1 inhibitor EX 527 reversed these effects. Additionally, SIRT1 activation significantly suppressed the ROS generation, leading to increase mitochondrial membrane potential and COX IV expression. Most importantly, the expression of tight junction molecules contributing to maintain intestinal barrier integrity was significantly up-regulated. Collectively, these findings indicated that autophagy/mitophagy elevation caused by SIRT1/PGC-1α pathway activation might be a protective mechanism to increase tight junction integrity against oxidative stress-mediated ROS production in IPEC-1 cells.
氧化应激导致肠上皮细胞损伤,进而引发紧密连接损伤和全身内源性应激综合征。有证据表明,SIRT1/PGC-1α 通路与氧化损伤密切相关。然而,SIRT1/PGC-1α 通路在保护肠上皮细胞免受氧化应激方面的作用机制仍有待阐明。在本研究中,我们研究了 SIRT1/PGC-1α 通路在调节猪肠上皮细胞(IPEC-1)氧化功能障碍相关自噬/线粒体自噬和紧密连接蛋白表达中的功能作用。结果表明,HO 暴露导致 ROS 大量积累,线粒体膜电位降低,紧密连接分子在 IPEC-1 细胞中的表达受到抑制。此外,COX IV mRNA 表达和 SIRT1/PGC-1α 通路受到抑制。HO 处理后自噬和 PINK1/Parkin 依赖性线粒体自噬被激活。进一步的研究表明,特异性激活剂 SRT 1720 激活 SIRT1/PGC-1α 通路导致自噬/线粒体自噬相关标志物升高,SIRT1 抑制剂 EX 527 逆转了这些效应。此外,SIRT1 激活显著抑制 ROS 的产生,导致线粒体膜电位和 COX IV 表达增加。最重要的是,参与维持肠道屏障完整性的紧密连接分子的表达显著上调。综上所述,这些发现表明,SIRT1/PGC-1α 通路激活引起的自噬/线粒体自噬增加可能是一种保护机制,可增加紧密连接的完整性,以抵抗 IPEC-1 细胞中氧化应激介导的 ROS 产生。
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