Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.
Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Southern Medical University, Guangzhou, Guangdong, China.
J Surg Res. 2019 Jan;233:221-230. doi: 10.1016/j.jss.2018.07.019. Epub 2018 Aug 31.
The deactivation of SIRT3, a novel deacetylase located in mitochondria, can aggravate multiple organ dysfunction. However, the role of SIRT3 and its downstream targets in ischemia/reperfusion (I/R)-induced acute kidney injury (AKI) remain unknown.
I/R was reproduced in a rat model using a clamp placed on the left and right renal pedicles for 40 min. The rats were intraperitoneally injected with either the vehicle or a selective SIRT3 inhibitor (3-TYP) and scarified at different time points (4, 8, and 24 h after I/R). A portion of the renal tissue was extracted for histological analysis, and another portion was collected for the isolation of renal tubular epithelial cells for Western blotting, SOD2 and SIRT3 activity, cell apoptosis, and the determination of oxidative stress.
The I/R-induced AKI model was successfully reproduced and SIRT3 activity was considerably reduced than control (sham operated) group, accompanied by increased acetylation of SOD2 and p53, as well as their elevated physical interaction in extracted mitochondrial protein (all P values < 0.05). Moreover, SIRT3 suppression by 3-TYP treatment (comparing with the vehicle treatment group) aggravated AKI, as evidenced by increased indicators of oxidative stress (increased mitochondrial red fluorescence MitoSOX and decreased reduced glutathione/oxidized glutathione ratio, all P values < 0.01).
The elevation of SOD2 and p53 protein acetylation in the mitochondria of renal tubular epithelial cells is an important signaling event in the pathogenesis of I/R-induced AKI. Thus, deacetylase SIRT3 may be an upstream regulator of both SOD2 and p53, and the SIRT3 deactivation may aggravate AKI.
位于线粒体中的新型去乙酰化酶 SIRT3 的失活会加重多器官功能障碍。然而，SIRT3 及其下游靶点在缺血/再灌注（I/R）诱导的急性肾损伤（AKI）中的作用尚不清楚。
使用夹在左右肾蒂上 40 分钟的方法在大鼠模型中复制 I/R。大鼠腹膜内注射载体或选择性 SIRT3 抑制剂（3-TYP），并在 I/R 后不同时间点（4、8 和 24 小时）宰杀。提取一部分肾组织进行组织学分析，另一部分收集用于分离肾管状上皮细胞进行 Western blot、SOD2 和 SIRT3 活性、细胞凋亡和氧化应激测定。
成功复制了 I/R 诱导的 AKI 模型，与对照组（假手术）相比，SIRT3 活性显著降低，同时 SOD2 和 p53 的乙酰化增加，以及它们在提取的线粒体蛋白中的物理相互作用增强（所有 P 值均<0.05）。此外，通过 3-TYP 处理（与载体处理组相比）抑制 SIRT3 加重了 AKI，这表现为氧化应激指标增加（线粒体红色荧光 MitoSOX 增加，还原型谷胱甘肽/氧化型谷胱甘肽比值降低，所有 P 值均<0.01）。
肾管状上皮细胞线粒体中 SOD2 和 p53 蛋白乙酰化的升高是 I/R 诱导的 AKI 发病机制中的一个重要信号事件。因此，去乙酰化酶 SIRT3 可能是 SOD2 和 p53 的上游调节剂，SIRT3 的失活可能加重 AKI。
