Contribution of mitochondrial GSH transport to matrix GSH status and colonic epithelial cell apoptosis
Contribution of mitochondrial GSH transport to matrix GSH status and colonic epithelial cell apoptosis
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DOI：
10.1016/j.freeradbiomed.2007.09.011
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发表时间：
2008-03-01
影响因子：
7.4
通讯作者：
Aw, Tak Yee
中科院分区：
文献类型：
--
作者：
Circu, Magdalena L.;Rodriguez, Cynthia;Aw, Tak Yee
在此之前。我们发现细胞内的谷胱甘肽/谷胱甘肽二硫键(GSH/GSSG)在细胞凋亡信号转导中起重要作用，早期的研究将线粒体GSH(MtGSH)的缺失与细胞毒性增强联系起来。目前的研究集中在线粒体GSH转运和线粒体GSH/GSSG状态在未转化的结肠上皮细胞系NCM460细胞凋亡启动中的作用，使用具有氧化还原循环活性的苯二酮(MQ)作为氧化挑战的模型。我们的结果表明，半喹酮自由基参与了MQ介导的细胞凋亡，这与线粒体可溶性GSH和蛋白结合的硫醇池的显著氧化、细胞色素c从线粒体到胞浆的移位以及caspase-9的激活有关。MQ诱导的细胞凋亡可通过抑制mtGSH摄取而增强，线粒体GSSG和蛋白SSG的增加与线粒体呼吸活性的降低相一致。此外，N-乙酰-L-半胱氨酸(NAC)可阻止细胞凋亡，恢复细胞氧化还原动态平衡。重要的是，mtGSH转运抑制有效地阻断了NAC介导的保护作用，因为它不能减弱mtGSSG。这些结果支持线粒体GSH转运和mtGSH状态在氧化细胞杀伤中的重要性。(C)2007 Elsevier Inc.保留所有权利。
Previously. we showed that cellular glutathione/glutathione disulfide (GSH/GSSG) play an important role in apoptotic signaling, and early studies linked mitochondrial GSH (mtGSH) loss to enhanced cytotoxicity. The current study focuses on the contribution of mitochondrial GSH transport and mitochondrial GSH/GSSG status to apoptosis initiation in a nontransformed colonic epithelial cell line, NCM460, using menadione (MQ), a quinone with redox cycling bioreactivity, as a model of oxidative challenge. Our results implicate the semiquinone radical in MQ-mediated apoptosis, which was associated with marked oxidation of the mitochondrial soluble GSH and protein-bound thiol pools, mitochondria-to-cytosol translocation of cytochrome c, and activation of caspase-9. MQ-induced apoptosis was potentiated by inhibition of mtGSH uptake in accordance with exacerbated mitochondrial GSSG (mtGSSG) and protein-SSG and compromised mitochondrial respiratory activity. Moreover, cell apoptosis was prevented by N-acetyl-L-Cysteine (NAC) pretreatment, which restored cellular redox homeostasis. Importantly, mtGSH transport inhibition effectively blocked NAC-mediated protection in accordance with its failure to attenuate mtGSSG. These results support the importance of mitochondrial GSH transport and the mtGSH status in oxidative cell killing. (c) 2007 Elsevier Inc. All rights reserved.