Mitochondria-targeted Cytochrome P450 2E1 Induces Oxidative Damage and Augments Alcohol-mediated Oxidative Stress
Mitochondria-targeted Cytochrome P450 2E1 Induces Oxidative Damage and Augments Alcohol-mediated Oxidative Stress
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DOI：
10.1074/jbc.m110.121822
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发表时间：
2010-08-06
影响因子：
4.8
通讯作者：
Avadhani, Narayan G.
中科院分区：
文献类型：
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作者：
Bansal, Seema;Liu, Chuan-Peng;Avadhani, Narayan G.
乙醇诱导的细胞色素P450 2 E1（CYP 2 E1）也在不同的病理和生理条件下被诱导。包括我们在内的研究表明，CYP 2 E1是双峰靶向内质网（微粒体）（mc CYP 2 E1）和线粒体（mt CYP 2 E1）。在这项研究中，我们在主要表达mtCYP 2 E1或mc CYP 2 E1的稳定细胞系中研究了mtCYP 2 E1在乙醇介导的氧化应激中的作用。ER+突变（A2 L，A9 L）增加新生蛋白与信号识别颗粒结合的亲和力，优先将CYP 2 E1靶向内质网。Mt+（L17 G）和Mt++（I8 R，L11 R，L17 R）突变蛋白，显示出逐渐降低的信号识别颗粒结合亲和力，以相应的更高水平靶向线粒体。GSH消耗的速率，作为氧化应激的量度，在表达Mt++和Mt+蛋白的细胞中比表达ER+蛋白的细胞更高。此外，细胞水平的F-2-异前列腺素，氧化应激的直接指标，在乙醇处理后的Mt++细胞显着增加。值得注意的是，Mt++ CYP 2 E1蛋白在酵母细胞中的表达比野生型或ER+蛋白引起更严重的线粒体DNA损伤和呼吸缺陷，如通过细胞不能在甘油或乙醇上生长所测试的。此外，含有高mt CYP 2 E1的乙醇喂养大鼠的肝线粒体显示出更高水平的F-2-异前列烷产生。这些结果有力地表明，mt CYP 2 E1诱导氧化应激，并增强酒精介导的细胞/组织损伤。
The ethanol-inducible cytochrome P450 2E1 (CYP2E1) is also induced under different pathological and physiological conditions. Studies including ours have shown that CYP2E1 is bimodally targeted to both the endoplasmic reticulum (microsomes) (mc CYP2E1) and mitochondria (mt CYP2E1). In this study we investigated the role of mtCYP2E1 in ethanol-mediated oxidative stress in stable cell lines expressing predominantly mt CYP2E1 or mc CYP2E1. The ER+ mutation (A2L, A9L), which increases the affinity of the nascent protein for binding to the signal recognition particle, preferentially targets CYP2E1 to the endoplasmic reticulum. The Mt+ (L17G) and Mt++ (I8R, L11R, L17R) mutant proteins, showing progressively lower affinity for signal recognition particle binding, were targeted to mitochondria at correspondingly higher levels. The rate of GSH depletion, used as a measure of oxidative stress, was higher in cells expressing Mt++ and Mt+ proteins as compared with cells expressing ER+ protein. In addition, the cellular level of F-2-isoprostanes, a direct indicator of oxidative stress, was increased markedly in Mt++ cells after ethanol treatment. Notably, expression of Mt++ CYP2E1 protein in yeast cells caused more severe mitochondrial DNA damage and respiratory deficiency than the wild type or ER+ proteins as tested by the inability of cells to grow on glycerol or ethanol. Additionally, liver mitochondria from ethanol-fed rats containing high mt CYP2E1 showed higher levels of F-2-isoprostane production. These results strongly suggest that mt CYP2E1 induces oxidative stress and augments alcohol-mediated cell/tissue injury.