SGK1 Attenuates Oxidative Stress-Induced Renal Tubular Epithelial Cell Injury by Regulating Mitochondrial Function
SGK1 Attenuates Oxidative Stress-Induced Renal Tubular Epithelial Cell Injury by Regulating Mitochondrial Function
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DOI：
10.1155/2019/2013594
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发表时间：
2019-09-18
影响因子：
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通讯作者：
Zhang, Xiaoli
中科院分区：
文献类型：
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作者：
Jiang, Daofang;Fu, Chensheng;Zhang, Xiaoli
线粒体功能障碍与许多肾脏疾病的早期或进展有关。改善线粒体功能和体内平衡有可能保护肾功能。已知血清和糖皮质激素诱导的激酶1 （SGK1）调节各种细胞过程，包括细胞存活。在这项研究中，我们打算证明SGK1在肾小管细胞氧化应激损伤中的作用和分子机制，并确定线粒体功能的调节是否参与这一过程。将HK-2细胞暴露于H2O2中，通过CCK-8法和annexin-V/PI染色动态检测细胞活力和凋亡情况。流式细胞术或western blot检测细胞活性氧（ROS）和三磷酸腺苷（ATP）浓度及SGK1/GSK3 β /PGC-1 α信号通路的表达。此外，在H2O2暴露前，在培养基中加入靶向SGK1和SB216763的shRNA，分别下调SGK1和GSK3 β。检测细胞活力和线粒体功能，包括线粒体膜电位（δ psi m）、细胞色素C释放、mtDNA拷贝数和线粒体生物发生。H2O2暴露显著刺激了蛋白水平和SGK1的激活。与对照组细胞相比，SGK1抑制的HK-2细胞对h2o2诱导的氧化应激损伤更敏感，因为它们表现出更多的凋亡细胞死亡和线粒体功能障碍，包括细胞ATP生成恶化、ROS积累、线粒体膜电位降低和细胞色素C释放到细胞质中。对SGK1敲低的研究也表明，SGK1是诱导与线粒体生物发生相关的蛋白质所必需的，包括PGC-1 α、NRF-1和TFAM。此外，SGK1抑制对细胞凋亡和线粒体功能（包括线粒体生物发生）的有害影响与GSK3 β的磷酸化有关，并通过SB216763处理部分逆转。H2O2导致HK-2细胞中SGK1过表达，通过改善线粒体功能和灭活GSK3 β来保护人肾小管细胞免受氧化应激损伤。
Mitochondrial dysfunction has been implicated in the early stages or progression of many renal diseases. Improving mitochondrial function and homeostasis has the potential to protect renal function. Serum- and glucocorticoid-induced kinase 1 (SGK1) is known to regulate various cellular processes, including cell survival. In this study, we intend to demonstrate the effect and molecular mechanisms of SGK1 in renal tubular cells upon oxidative stress injury and to determine whether regulation of mitochondrial function is implicated in this process. HK-2 cells were exposed to H2O2, and cell viability and apoptosis were dynamically detected by the CCK-8 assay and annexin-V/PI staining. The concentrations of cellular reactive oxygen species (ROS) and adenosine triphosphate (ATP) and the expression of the SGK1/GSK3 beta/PGC-1 alpha signaling pathway were analyzed by flow cytometry or western blot. In addition, shRNA targeting SGK1 and SB216763 were added into the culture medium before H2O2 exposure to downregulate SGK1 and GSK3 beta, respectively. Cell viability and mitochondrial functions, including mitochondrial membrane potential (Delta psi m), Cytochrome C release, mtDNA copy number, and mitochondrial biogenesis, were examined. Protein levels and SGK1 activation were significantly stimulated by H2O2 exposure. HK-2 cells with SGK1 inhibition were much more sensitive to H2O2-induced oxidative stress injury than control group cells, as they exhibited increased apoptotic cell death and mitochondrial dysfunction involving the deterioration of cellular ATP production, ROS accumulation, mitochondrial membrane potential reduction, and release of Cytochrome C into the cytoplasm. Studies on SGK1 knockdown also indicated that SGK1 is required for the induction of proteins associated with mitochondrial biogenesis, including PGC-1 alpha, NRF-1, and TFAM. Moreover, the deleterious effects of SGK1 suppression on cell apoptosis and mitochondrial function, including mitochondrial biogenesis, were related to the phosphorylation of GSK3 beta and partially reversed by SB216763 treatment. H2O2 leads to SGK1 overexpression in HK-2 cells, which protects human renal tubule cells from oxidative stress injury by improving mitochondrial function and inactivating GSK3 beta.