Numb在肾脏细胞自噬中的作用及其机制研究

项目名称： Numb在肾脏细胞自噬中的作用及其机制研究

项目编号： No.81500514

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 医药、卫生

项目作者： 艾军

作者单位： 南方医科大学

项目金额： 20万元

中文摘要： 急性肾损伤(AKI)增加住院患者死亡率和致残率，也是致慢性肾衰竭的重要原因，肾小管上皮细胞损伤是其主要病理表现。自噬在AKI中具有保护作用。Numb是一个高度保守的蛋白，具有多种生物学功能，但其在肾脏功能不清。我们发现，Numb在肾小管上皮细胞广泛表达，且在AKI时表达显著上升；沉默Numb导致p62降低，LC3II上升，提示下调Numb促进自噬。研究表明，胞浆p53抑制自噬，而Numb可与p53及HDM2结合形成三聚体，抑制p53降解。我们也发现，沉默Numb后p53显著降低；因此，我们提出假设：Numb通过抑制p53降解，增加p53蛋白水平，抑制细胞自噬，促进AKI损伤。我们将分别上调、下调Numb明确Numb对肾小管上皮细胞自噬的作用及其机制；建立肾脏Numb基因敲除小鼠，验证Numb通过抑制自噬加重AKI损伤的机制。本研究将进一步揭示AKI的损伤机制，为临床防治AKI提供新靶点。

中文关键词： Numb；细胞自噬；肿瘤抑制因子p53；急性肾损伤；Numb敲除小鼠

英文摘要： Acute kidney injury (AKI) is a major renal disease associated with significant mortality and the development of chronic kidney disease and end-stage renal disease. However, current treatment options are limited. Pathologically, AKI is characterized by tubular cell injury and death. Recent studies have demonstrated that autophagy is rapidly induced during AKI to protect tubular cells from injury and death. .Numb plays a critical role in cell endocytosis, adhesion, migration, differentiation, and self-renewal. Our previous studies showed that Numb was well expressed in renal tubular epithelial cells. In renal ischemia-reperfusion injury and cisplatin induced AKI mice, renal Numb protein expression was significantly upregulated. Our further studies showed that reduction of Numb could down-regulate p62 and up-regulate LC3II protein expression. These data suggested that reduction of Numb might promote renal autophagy. .Studies had shown cytosolic p53 inhibited autophagy, and Numb plays a role in p53 stabilization. Over-expression of Numb increases the level of p53, while reduction of Numb causes a decrease p53 expression. Our studies also showed that reduction of Numb could down-regulate p53 protein expression，suggesting that Numb might inhibite autophagy via p53 stabilization..We are going to validate this hypotheses by the following studies. Firstly, we are going to detect the changes of autophage in Numb over-expression and knock-down renal epithelial cells. Secondly, we are going to examine the changes of autophage in Numb over-expression cells when inhibiting p53 expression or Numb knock-down cells when inhibiting HDM2 expression. At last, we are going to confirm these changes in renal Numb gene knock-out mice.

英文关键词： Numb;autophagy;tumor suppressor p53;acute renal failure;Numb knock-out mice