The stress-response molecule NR4A1 resists ROS-induced pancreatic beta-cells apoptosis via WT1
The stress-response molecule NR4A1 resists ROS-induced pancreatic beta-cells apoptosis via WT1
复制标题
应激反应分子 NR4A1 通过 WT1 抵抗 ROS 诱导的胰腺 β 细胞凋亡
DOI：
10.1016/j.cellsig.2017.03.012
复制
发表时间：
2017
影响因子：
4.8
通讯作者：
Wang Xiangdong
中科院分区：
文献类型：
--
作者：
Zong Chen;Qin D;an;Yu Cong;Gao Peng;Chen Jicui;Lu Sumei;Zhang Yuchao;Liu Yuantao;Yang Yingfeng;Pu Zeqing;Li Xia;Fu Yuchang;Guan Qingbo;Wang Xiangdong
在不利条件下，胰腺β细胞通常面临内质网应激和/或ROS相关的氧化应激。我们的前期工作已经证实NR 4A 1对ER应激诱导的胰腺β细胞凋亡具有保护作用。然而，NR 4A 1是否能够保护胰腺β细胞免受ROS相关的氧化应激仍然是未知的。在本研究中，我们的数据表明，NR 4A 1蛋白表达迅速增加MIN 6细胞后，H2 O2处理，和NR 4A 1在MIN 6细胞的过表达赋予抵抗细胞凋亡由H2 O2诱导。这些结果在来自感染过表达NR 4A 1的腺病毒的小鼠的分离胰岛中得到进一步证实。8-羟基-2 ′-脱氧鸟苷（8-OHdG）被用作氧化应激的生物标志物或ROS损伤的标志物。我们发现，高脂饮食喂养的NR 4A 1基因敲除小鼠胰岛中8-OHdG水平明显高于亲本对照小鼠胰岛; NR 4A 1基因敲除小鼠胰岛中8-OHdG的凋亡率高于对照小鼠。对NR 4A 1保护作用的潜在机制的进一步研究表明，NR 4A 1在MIN 6细胞中的过表达减少了H2 O2引起的Caspase 3活化，并增加了WT 1和SOD 1的表达。在WT 1启动子中存在一个推测的NR 4A 1结合位点（− 1118 bp至− 1111 bp）;我们的数据表明NR 4A 1蛋白与WT 1启动子物理结合，增强了WT 1启动子的反式激活，并在MIN 6细胞中敲低WT 1诱导凋亡。这些结果表明NR 4A 1通过上调WT 1的表达来保护胰腺β细胞免受H2 O2介导的凋亡。
Pancreatic β-cells often face endoplasmic reticulum stress and/or ROS-associated oxidative stress under adverse conditions. Our previous work has verified that NR4A1 protects pancreatic β-cells from ER-stress induced apoptosis. However, It remains unknown whether NR4A1 is able to protect pancreatic β-cells against ROS-associated oxidative stress. In the present study, our data showed that NR4A1 protein expression rapidly increased in MIN6 cells upon H2O2treatment, and overexpression of NR4A1 in MIN6 cells conferred resistance to cell apoptosis induced by H2O2. These results were further substantiated in isolated islets from mice infected with an adenovirus overexpressing NR4A1. 8-hydroxy-2′-deoxyguanosine (8-OHdG) was used as a biomarker for oxidative stress or a marker for ROS damage. We found that the 8-OHdG level in the islets from NR4A1 knockout mice fed with high-fat diet was much higher than that in the islets from parental control mice; and higher apoptotic rate was observed in the islets from NR4A1 KO mice compared to control mice. Further investigation of underlying mechanisms of NR4A1’s protective effects showed that NR4A1 overexpression in MIN6 cells reduced Caspase 3 activation caused by H2O2, and increased expression of WT1 and SOD1. There is a putative NR4A1 binding site (− 1118 bp to − 1111 bp) in WT1 promoter; our data demonstrated that NR4A1 protein physically associates with the WT1 promoter, and enhanced WT1 promoter transactivation and knockdown of WT1 in MIN6 cells induced apoptosis. These findings suggest that NR4A1 protects pancreatic β-cells against H2O2mediated apoptosis by up-regulating WT1 expression.