The orphan nuclear receptor NR4A1 attenuates oxidative stress-induced beta cells apoptosis via up-regulation of glutathione peroxidase 1
The orphan nuclear receptor NR4A1 attenuates oxidative stress-induced beta cells apoptosis via up-regulation of glutathione peroxidase 1
复制标题
孤儿核受体 NR4A1 通过上调谷胱甘肽过氧化物酶 1 减弱氧化应激诱导的 β 细胞凋亡
DOI：
10.1016/j.lfs.2018.04.027
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发表时间：
2018
期刊：
影响因子：
6.1
通讯作者：
Wang Xiangdong
中科院分区：
文献类型：
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作者：
Yang Yingfeng;Xie Fangyu;Qin D;an;Zong Chen;Han Feng;Pu Zeqing;Liu Dong;Li Xia;Zhang Yuchao;Liu Yuantao;Wang Xiangdong
目的我们前期的研究表明NR4A1对氧化应激诱导的细胞凋亡具有保护作用。然而，NR4A1下游的靶点并不完全清楚。谷胱甘肽过氧化物酶1（GPX 1）是谷胱甘肽过氧化物酶类中最常见的抗氧化酶。本研究旨在探讨GPX 1是否参与NR4A1对胰岛β细胞的保护作用。测定这些细胞中GPX 1表达和GPX 1启动子反式激活。用H2O2处理MIN6细胞，检测活化的caspase 3水平。关键发现：MIN6细胞中NR4A1的过表达导致GPX 1在mRNA和蛋白水平的表达增加。双荧光素酶分析表明NR4A1过表达能够增强GPX 1启动子的反式激活，并且GPX 1启动子中的关键调控元件被缩小到0至−2000 bp之间，并具有推定的NR4A1结合位点（−273至−268）。ChIP分析表明NR4A1与GPX1启动子物理缔合。H2O2处理后，GPX1的过表达降低了Caspase 3的活性水平，NR4A1通过与GPX1启动子上的结合位点结合，增强GPX1启动子的反式激活，从而促进GPX1的表达。NR4A1可能通过增加GPX1表达来保护胰腺β细胞免受氧化应激诱导的凋亡。
AimsOur previous study showed that NR4A1 protects against oxidative stress-induced cell apoptosis. However, the targets downstream of NR4A1 are incompletely known. Glutathione peroxidase 1 (GPX1) is the most common antioxidant enzyme in the glutathione peroxidase class. In this study, we aimed to investigate whether GPX1 is a mediator of the protective effects of NR4A1 in pancreatic β cells.Main methodsA pancreatic β cell line, MIN6, was used to generate NR4A1 over-expression cell line. GPX1 expression and GPX1 promoter trans-activation in these cells was determined. These cells were then treated with H2O2, and the active caspase3 level was determined.Key findingsNR4A1 over-expression in MIN6 cells resulted in increased GPX1 expression at both mRNA and protein levels. Dual luciferase assay showed that NR4A1 over-expression was able to enhance the trans-activation of GPX1 promoter, and the critical regulatory elements were narrowed down between 0 to −2000 bp in GPX1 promoter with a putative NR4A1 binding site (−273 to −268). ChIP assays demonstrated that NR4A1 physically associates with the GPX1 promoter. Over-expression of GPX1 reduced the active level of Caspase3 after H2O2treatment.SignificanceNR4A1 increases the expression of GPX1 by enhancing the trans-activation of GPX1 promoter through binding to the putative binding site on GPX1 promoter. NR4A1 potentially protects pancreatic β cells against oxidative stress-induced apoptosis by increasing GPX1 expression.