Nrf2 is increased by CYP2E1 in rodent liver and HepG2 cells and protects against oxidative stress caused by CYP2E1
Nrf2 is increased by CYP2E1 in rodent liver and HepG2 cells and protects against oxidative stress caused by CYP2E1
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DOI：
10.1002/hep.21004
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发表时间：
2006-01-01
期刊：
影响因子：
13.5
通讯作者：
Cederbaum, AI
中科院分区：
文献类型：
--
作者：
Gong, PF;Cederbaum, AI
乙醇对CYP 2 E1的诱导是乙醇产生氧化应激的一种途径。Nrf 2是一种转录因子，调节重要的抗氧化剂和II期解毒基因。研究了CYP 2 E1对Nrf 2的诱导作用及其在对CYP 2 E1引起的氧化应激增加的适应性反应中的重要性。在慢性酒精喂养的小鼠或大鼠以及吡唑处理的大鼠或小鼠的肝脏或肝细胞中观察到Nrf 2蛋白和mRNA的增加，与对照HepG 2 C34细胞相比，已知升高CYP 2 E1的条件下表达CYP 2 E1的HepG 2细胞（E47细胞）显示Nrf 2 mRNA和蛋白表达增加。Nrf 2在E47细胞中被激活，如核Nrf 2水平和Nrf 2-抗氧化剂反应元件结合活性的增加以及Nrf 2调节基因、谷氨酸半胱氨酸连接酶催化亚基（GCLC）和血红素加氧酶1（HO-1）的上调所示。CYP 2 E1活性抑制剂和活性氧（ROS）清除剂N-乙酰半胱氨酸可阻断Nrf 2蛋白和mRNA的增加，从而降低ROS水平以及Nrf 2 mRNA诱导。E47细胞中GCLC和HO-1的上调依赖于Nrf 2，并被siRNA-Nrf 2阻止。通过siRNA-Nrf 2阻断Nrf 2降低谷胱甘肽并增加ROS和脂质过氧化，导致E47细胞而不是C34细胞的线粒体膜电位降低和细胞活力丧失。这些结果表明，当CYP 2 E1升高时，Nrf 2被激活，蛋白质和mRNA水平升高。总之，Nrf 2在对抗由CYP 2 E1引起的氧化应激增加的适应性反应中起关键作用。本文的补充材料可在肝脏病学网站（http：//interscience.wiley.com/jpages/0270-9139/suppmat/index.html）上找到。
Induction of CYP2E1 by ethanol is one pathway through which ethanol generates oxidative stress. Nrf2 is a transcription factor that regulates important antioxidant and phase II detoxification genes. Nrf2 induction by CYP2E1 and its importance in the adaptive response to increased oxidative stress caused by CYP2E1 was studied. Increases in Nrf2 protein and mRNA were observed in livers or hepatocytes of chronic alcohol-fed mice or rats and of pyrazole-treated rats or mice, conditions known to elevate CYP2E1 HepG2 cells expressing CYP2E1 (E47 cells) showed increased Nrf2 mRNA and protein expression compared with control HepG2 C34 cells. Nrf2 is activated in E47 cells as shown by an increase in nuclear Nrf2 levels and Nrf2-antioxidant-responsive element binding activity, and upregulation of Nrf2-regultated genes, glutamate cysteine ligase catalytic subunit (GCLC), and heme oxygenase 1 (HO-1). Increases in Nrf2 protein and mRNA are blocked by inhibitors of CYP2E1 activity and a reactive oxygen species (ROS) scavenger, N-acetylcysteine, which decrease ROS levels as well as Nrf2 mRNA induction. Upregulation of GCLC and HO-1 in E47 cells is dependent on Nrf2 and is prevented by siRNA-Nrf2. Blocking Nrf2 by siRNA-Nrf2 decreases glutathione and increases ROS and lipid peroxidation, resulting in decreased mitochondrial membrane potential and loss of cell viability of E47 cells but not C34 cells. These results suggest that Nrf2 is activated and that levels of protein and mRNA are increased when CYP2E1 is elevated. In conclusion, Nrf2 plays a key role in the adaptive response against increased oxidative stress caused by CYP2E1. Supplementary material for this article can be found on the HEPATOLOGY Website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).