NR4A1 通过上调Survivin、WT1及GPX1的表达以抵抗活性氧所致胰岛β细胞的凋亡

持续高糖及高脂可导致胰岛β细胞代谢中活性氧（ROS）的升高进而增加了细胞凋亡的危险。我们前期研究显示：β细胞MIN6过表达NR4A1可抵抗H2O2引起的细胞凋亡，过表达NR4A1上调Survivin、WT1和GPX1的表达，也使WT1调控的下游分子SOD1、Bcl-2表达升高。我们假说：NR4A1上调Survivin 、WT1和 GPX1的表达，它们的蛋白表达产物或下游产物可抵抗ROS所致的β细胞凋亡。为证假说，拟在β细胞中过表达或敲出NR4A1的表达，以观察NR4A1改变后胰岛β细胞对ROS敏感性及对ROS清除能力的改变；分析NR4A1所上调的Survivin、WT1及GPX1对抵抗ROS所致β细胞凋亡的贡献及协同效应，并分析相关表达调控机制；借助NR4A1敲除小鼠验证NR4A1抵抗ROS所致β细胞凋亡的作用；探索高脂饮食对NR4A1基因敲除小鼠胰岛的影响。此研究可为糖尿病防治提供线索。

Sustained hyperglycemia and hyperlipidimia will result in increased ROS in pancreatic βcells further increase the potential of apoptosis. Our preliminary data showed: over-expression NR4A1 in pancreaticβcells (MIN6 cells) resisted H2O2-induced apoptosis, up-regulated the expression of Survivin , WT1 and GPX1，also resulted in the increased expression of SOD1 and Bcl-2 which are two down-stream molecules of WT1. We hypothesize that NR4A1 protects pancreatic βcell from ROS-induced apoptosis by up-regulating the expression of Survivin , WT1 and GPX1 or their downstream molecules. In order to verify the hypothesis, over-expression NR4A1 MIN6 cell lines and NR4A1 knock-down MIN6 cell lines will be exploited to observe the sensitivity change upon ROS treatment, the capability changes for ROS clearance; analyzing the contributions of Survivin, WT1 and GPX1 in the control of NR4A1 for protecting βcells from apoptosis caused by ROS, figuring out if these proteins have the synergetic effect on anti-oxidative-stress, and exploring the related mechanisms for up-regulation of these genes by NR4A1; the NR4A1 KO mice will be exploited to testify the protective effect of NR4A1 on pancreatic βcells from ROS, and to explore the damage of pancreatic βcells in islets of mice fed with high fat diet. This result of this project will provide clues for diabetes prevention.