应激致线粒体基因（mitochondrial DNA，mtDNA）稳定性失衡启动肾小管上皮细胞（Renal tubular cell, RTC）损伤是急性肾损伤（Acute kidney injury，AKI）的重要病理基础，机制未明。DNA2是新近鉴定的维持mtDNA稳定性的关键蛋白，课题组前期发现DNA2在AKI应激状态下发生细胞内再分布导致mtDNA稳定性丢失，且可能由E3泛素连接酶TRAF6及其协同蛋白TIFA介导。本研究拟进一步，建立TIFA、TRAF6及DNA2的RTC表达干预模型和敲除小鼠AKI模型，并通过蛋白质共表达、胞内迁移、泛素化修饰等的分析，评价蛋白质互作对mtDNA稳定性的调控，从分子、细胞及体内水平阐明介导应激损伤中RTC mtDNA稳定性失衡的TIFA/TRAF6/DNA2互作机制及其效应机制。本研究有助于深入理解AKI的病理机制，为疾病防治提供新线索。

Mitochondrial DNA (mtDNA) instability caused by stress factors inducing renal tubular cell (RTC) injury, which serves as a basis of the pathological change of acute kidney injury (AKI) and its regulating mechanism is unclear. Recently, DNA2 was identified as a key protein to maintain stability of nuclear genome as well as mtDNA. Our preliminary study indicated that DNA2 induced mtDNA instability due to its intracellular re-localization, which might be mediated by E3 ubiquitin ligase TRAF6 and its co-activator TIFA. The present study aims to further investigate the regulatory role and mechanism of TIFA/TRAF6/DNA2 pathway mediating RTC mtDNA instability under stress. The TIFA, TRAF6 and DNA2 expression manipulated cell models will be established and their biological function, including expression variations on gene or protein level, intracellular localization or migration, ubiquitin level change, etc, will be evaluated. Furthermore, the animal models of ischemia reperfusion AKI, septic AKI and drug toxicity AKI will be established on TRAF6 knock out mice, to confirm the mtDNA instability regulating mechanism in vivo. As the increasing prevalence of AKI, the results of this study will not only expand our understanding of the mechanisms of AKI, but also assist in the eventual development of new therapeutic targets for the disease.