Glutathione Peroxidase-1 Regulates Mitochondrial Function to Modulate Redox-dependent Cellular Responses
Glutathione Peroxidase-1 Regulates Mitochondrial Function to Modulate Redox-dependent Cellular Responses
复制标题
DOI：
10.1074/jbc.m900392200
复制
发表时间：
2009-05-01
影响因子：
4.8
通讯作者：
Loscalzo, Joseph
中科院分区：
文献类型：
--
作者：
Handy, Diane E.;Lubos, Edith;Loscalzo, Joseph
谷胱甘肽过氧化物酶-1（GPx-1）是一种含硒半胱氨酸的酶，在细胞中过氧化物的还原解毒中起主要作用。在GPx-1过表达约2倍的永久转染细胞中，我们发现，细胞内积累的氧化剂响应外源性过氧化氢减少，是表皮生长因子受体（EGFR）介导的Akt激活响应过氧化氢或EGF刺激。GPx-1的敲低增强EGFR介导的Akt活化，而过氧化氢酶的过表达降低Akt活化，表明EGFR信号传导受氧化还原机制调节。为了确定线粒体氧化剂是否在这些过程中发挥作用，在EGF刺激之前用线粒体解偶联剂预处理细胞。线粒体功能的抑制减弱了对照细胞中EGF介导的Akt活化，但在GPx-1过表达细胞中没有额外的作用，表明GPx-1过表达通过减少线粒体氧化剂降低EGFR信号传导。与这一发现一致，GPx-1过表达减少了全球蛋白质二硫键的形成，这是依赖于神经产生的氧化剂。GPx-1过表达，在永久转染或腺病毒处理的细胞，也引起整体线粒体功能障碍，线粒体电位下降，ATP生产减少。GPx-1过表达也降低了EGF和血清介导的[H-3]胸苷掺入，表明GPx-1的改变可以减弱细胞增殖。总之，这些数据表明，GPx-1可以通过调节线粒体功能来调节氧化还原依赖性细胞反应。
Glutathione peroxidase-1 (GPx-1) is a selenocysteine-containing enzyme that plays a major role in the reductive detoxification of peroxides in cells. In permanently transfected cells with approximate 2-fold overexpression of GPx-1, we found that intracellular accumulation of oxidants in response to exogenous hydrogen peroxide was diminished, as was epidermal growth factor receptor (EGFR)-mediated Akt activation in response to hydrogen peroxide or EGF stimulation. Knockdown of GPx-1 augmented EGFR-mediated Akt activation, whereas overexpression of catalase decreased Akt activation, suggesting that EGFR signaling is regulated by redox mechanisms. To determine whether mitochondrial oxidants played a role in these processes, cells were pretreated with a mitochondrial uncoupler prior to EGF stimulation. Inhibition of mitochondrial function attenuated EGF-mediated activation of Akt in control cells but had no additional effect in GPx-1-overexpressing cells, suggesting that GPx-1 overexpression decreased EGFR signaling by decreasing mitochondrial oxidants. Consistent with this finding, GPx-1 overexpression decreased global protein disulfide bond formation, which is dependent on mitochondrially produced oxidants. GPx-1 overexpression, in permanently transfected or adenovirus-treated cells, also caused overall mitochondrial dysfunction with a decrease in mitochondrial potential and a decrease in ATP production. GPx-1 overexpression also decreased EGF- and serum-mediated [H-3] thymidine incorporation, indicating that alterations in GPx-1 can attenuate cell proliferation. Taken together, these data suggest that GPx-1 can modulate redox-dependent cellular responses by regulating mitochondrial function.