Department of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China.
Nephrology and Urology Research Institute of Wuhan University, Wuhan, Hubei, China.
Cell Prolif. 2023 Feb;56(2):e13362. doi: 10.1111/cpr.13362. Epub 2022 Nov 26.
Acute kidney injury (AKI) is often secondary to sepsis. Increasing evidence suggests that mitochondrial dysfunction contributes to the pathological process of AKI. In this study, we aimed to examine the regulatory roles of Sirt3 in Lipopolysaccharide (LPS)-induced mitochondrial damage in renal tubular epithelial cells (TECs). Sirt3 knockout mice were intraperitoneally injected with LPS, and cultured TECs were stimulated with LPS to evaluate the effects of Sirt3 on mitochondrial structure and function in TECs. Electron microscopy was used to assess mitochondrial morphology. Immunofluorescence staining was performed to detect protein expression and examine mitochondrial morphology. Western blotting was used to quantify protein expression. We observed that LPS increased apoptosis, induced disturbances in mitochondrial function and dynamics, and downregulated Sirt3 expression in a sepsis-induced AKI mouse model and human proximal tubular (HK-2) cells in vitro. Sirt3 deficiency further exacerbated LPS-induced renal pathological damage, apoptosis and disturbances in mitochondrial function and dynamics. On the contrary, Sirt3 overexpression in HK-2 cells alleviated these lesions. Functional studies revealed that Sirt3 overexpression alleviated LPS-induced mitochondrial damage and apoptosis in TECs by promoting OPA1-mediated mitochondrial fusion through the deacetylation of i-AAA protease (YME1L1), an upstream regulatory molecule of OPA1. Our study has identified Sirt3 as a vital factor that protects against LPS-induced mitochondrial damage and apoptosis in TECs via the YME1L1-OPA1 signaling pathway.
急性肾损伤（AKI）常继发于脓毒症。越来越多的证据表明，线粒体功能障碍参与了 AKI 的病理过程。在这项研究中，我们旨在研究 Sirt3 在脂多糖（LPS）诱导的肾小管上皮细胞（TEC）线粒体损伤中的调节作用。Sirt3 敲除小鼠经腹腔注射 LPS，培养的 TEC 用 LPS 刺激，以评估 Sirt3 对 TEC 中线粒体结构和功能的影响。电子显微镜用于评估线粒体形态。免疫荧光染色用于检测蛋白表达和观察线粒体形态。Western blot 用于定量蛋白表达。我们观察到 LPS 增加了细胞凋亡，诱导了线粒体功能和动力学的紊乱，并下调了脓毒症诱导的 AKI 小鼠模型和体外人近端肾小管（HK-2）细胞中的 Sirt3 表达。Sirt3 缺失进一步加重了 LPS 诱导的肾病理损伤、细胞凋亡和线粒体功能及动力学紊乱。相反，HK-2 细胞中的 Sirt3 过表达缓解了这些损伤。功能研究表明，Sirt3 过表达通过去乙酰化 OPA1 的上游调节分子 i-AAA 蛋白酶（YME1L1），促进 OPA1 介导的线粒体融合，从而减轻 LPS 诱导的 TEC 中线粒体损伤和凋亡。我们的研究表明，Sirt3 是一种重要的因子，通过 YME1L1-OPA1 信号通路保护 TEC 免受 LPS 诱导的线粒体损伤和凋亡。
