Glutamate-cysteine ligase attenuates TNF-induced mitochondrial injury and apoptosis
Glutamate-cysteine ligase attenuates TNF-induced mitochondrial injury and apoptosis
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DOI：
10.1016/j.freeradbiomed.2004.05.027
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发表时间：
2004-09-01
影响因子：
7.4
通讯作者：
Kavanagh, TJ
中科院分区：
文献类型：
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作者：
Botta, D;Franklin, CC;Kavanagh, TJ
谷胱甘肽(GSH)在清除自由基、维持细胞氧化还原状态、调节细胞对多种毒物的反应等方面发挥着重要作用。谷胱甘肽合成的限速酶是谷氨酸-半胱氨酸连接酶(GCL)，它由催化亚基(GCLC)和修饰亚基(GCLM)组成。为了确定增加的GSH生物合成能力是否增强了细胞对肿瘤坏死因子-α(TNF-α)诱导的细胞凋亡的抵抗力，我们建立了几个高表达GCLC和/或GCLM的小鼠肝肝癌(HEPA-1)细胞系。单独高表达GCLC的细胞表现出轻微的GCL活性增加，而同时过度表达两个亚基的细胞GCL活性有很大的增加。重要的是，过度表达这两个GCL亚基的细胞对肿瘤坏死因子诱导的细胞凋亡表现出更强的抵抗力，表现为氧化还原电位的丧失，线粒体膜电位的丧失，细胞色素c的移位到细胞质，以及caspase-3，caspase-8和caspase-9的激活。分析肿瘤坏死因子对这些参数的影响表明，在GCL过度表达的细胞中，保持线粒体的完整性介导了这种保护作用。(C)2004 Elsevier Inc.保留所有权利。
Glutathione (GSH) is important in free radical scavenging, maintaining cellular redox status, and regulating cell survival in response to a wide variety of toxicants. The rate-limiting enzyme in GSH synthesis is glutamate-cysteine ligase (GCL), which is composed of catalytic (GCLC) and modifier (GCLM) subunits. To determine whether increased GSH biosynthetic capacity enhances cellular resistance to tumor necrosis factor-alpha- (TNF-alpha-) induced apoptotic cell death, we have established several mouse liver hepatoma (Hepa- 1) cell lines overexpressing GCLC and/or GCLM. Cells overexpressing GCLC alone exhibit modest increases in GCL activity, while cells overexpressing both subunits have large increases in GCL activity. Importantly, cells overexpressing both GCL subunits exhibit increased resistance to TNF-induced apoptosis as judged by a loss of redox potential; mitochondrial membrane potential; translocation of cytochrome c to the cytoplasm; and activation of caspase-3, caspase-8, and caspase-9. Analysis of the effects of TNF on these parameters indicates that maintaining mitochondrial integrity mediates this protective effect in GCL-overexpressing cells. (C) 2004 Elsevier Inc. All rights reserved.