Elucidation of the mechanism of TNF-induced reactive oxygen species-dependent cytotoxicity and development of its clinical application

TNF诱导的活性氧依赖性细胞毒性机制的阐明及其临床应用的开发

基本信息

批准号：
15390131
负责人：
NAKANO Hiroyasu
金额：
$ 7.62万
依托单位：
Juntendo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

By using NF-κB activation-deficient cells, we demonstrate that TNFα stimulation leads to accumulation of reactive oxygen species(ROS), which is essential for prolonged mitogen-activated protein kinase(MAPK) activation and necrotic cell death. Moreover, microarray analysis shows that several antioxidant enzymes are induced by TNFα in an NF-κB-dependent manner. Collectively, a novel function of NF-κB is to suppress TNF-induced ROS accumulation by upregulating anti-oxidant enzymes.Accumulation of unfolded proteins in the endoplasmic reticulum(ER) causes ER overload, resulting in ER stress. To cope with ER stress, mammalian cells trigger a specific response known as the unfolded protein response(UPR). By using murine fibrosarcoma L929 cells, in which tumor necrosis factor(TNF)α induces accumulation of reactive oxygen species(ROS) and cell death, we show that TNFαTh induces the UPR in a ROS-dependent fashion. In contrast to TNFα, oxidative stresses by H_2O_2 or arsenite only induce eIF2α phosphorylation, but not activation of PERK- or IRE1-dependent pathways, indicating the specificity of downstream signaling induced by various oxidative stresses. Conversely, the UPR induced by tunicamycin substantially suppresses TNFα-induced ROS accumulation and cell death. Collectively, some, but not all, oxidative stresses induce the UPR, and preemptive UPR counteracts TNFα-induced ROS accumulation.

通过使用NF-κB激活缺陷细胞，我们证明TNFα刺激会导致活性氧（ROS）的积累，这对于延长促丝分裂原活化蛋白激酶（MAPK）激活和坏死细胞死亡至关重要。此外，微阵列分析表明，TNFα以NF-κB依赖性方式诱导了几种抗氧化剂。总体而言，NF-κB的新功能是通过上调抗氧化剂酶来抑制TNF诱导的ROS积累。内质网中展开的蛋白质的蓄积会导致ER超负荷，从而导致ER应力。为了应对质网应激，哺乳动物细胞会触发一种特定的反应，称为展开的蛋白质反应（UPR）。通过使用鼠纤维肉瘤L929细胞，其中肿瘤坏死因子（TNF）α诱导活性氧（ROS）和细胞死亡的积累，我们表明TNFαTH以ROS依赖性方式诱导UPR。与TNFα相反，H_2O_2或砷仅诱导EIF2α磷酸化，而不是激活PERK-或IRE1依赖性途径，这表明由各种氧化应激引起的下游信号传导的特异性。相反，衣霉素诱导的UPR基本上抑制了TNFα诱导的ROS积累和细胞死亡。总的来说，有些但不是全部，氧化应激会诱导UPR，而先发制人的UPR抵消了TNFα诱导的ROS积累。