Ethanol toxicity and NO-dependent mitochondrial damage

描述(申请人提供)：涉及的是活性氧(ROS) 在高浓度乙醇的肝脏毒性中。一系列机制 如线粒体GSH浓度降低，抑制 呼吸作用和对低氧的敏感度增加。焦点 这项建议的目的是检查乙醇对肝脏线粒体的影响。 一氧化氮(NO)、活性氮(RNS)介导的功能 还有罗斯。先前的研究和初步数据表明，双相 NO在线粒体中的作用可以通过对两者的控制来证明。 呼吸功能和导致细胞色素c释放的过程。 尽管乙醇引起的许多线粒体缺陷也可以 由RNS引起的一种机械性联系尚未得到检验。发展出的概念 在这个提议中，一氧化氮在乙醇中被转化为线粒体毒素 通过与ROS的反应消耗。支持这一假说的关键发现 在体内酒精摄取诱导诱导型一氧化氮合酶，其产物一氧化氮是一种 线粒体呼吸的强大调节器2)这与 相反，酪氨酸硝化增加--RNS3)NO的标记物--抑制 细胞色素c从线粒体释放，而RNS，如过氧亚硝酸盐， 促进这种促凋亡因子的释放4)长期饮酒 导致肝细胞对低氧应激更敏感。这些数据 导致了一种假说，一种导致酒精的关键机制 肝毒性是通过对线粒体功能的NO依赖修饰而实现的。 这一概念将通过在野外追求以下具体目标来检验 类型和诱导型一氧化氮合酶淘汰饮酒小鼠：1.确定 长期饮酒增加了线粒体呼吸中的NO， 抗氧化能力和ROS/RNS的形成。2.确定慢性病的影响 饮酒对细胞色素c释放和线粒体蛋白的影响 在分离的细胞器和肝细胞中的修饰。3.确定 NO依赖对线粒体蛋白质合成的影响及对NO的反应 慢性酒精摄入后肝细胞对低氧应激的影响。

DESCRIPTION (provided by applicant): Reactive oxygen species (ROS) are involved in the hepatotoxicity of high concentrations of ethanol. A number of mechanisms such as decreased concentrations of mitochondrial GSH, inhibition of respiration and enhanced susceptibility to hypoxia have been invoked. The focus of this proposal is to examine the effects of ethanol on hepatic mitochondrial function mediated through nitric oxide (NO), reactive nitrogen species (RNS) and ROS. Previous studies and preliminary data have shown that a biphasic effect of NO can be demonstrated in mitochondria in terms of control of both respiratory function and the processes leading to cytochrome c release. Although many of the mitochondrial defects elicited by ethanol can also be caused by RNS a mechanistic link has not been examined. The concept developed in this proposal is that NO is converted to a mitochondrial toxin on ethanol consumption by reaction with ROS. Key findings in support of this hypothesis are 1) iNOS is induced on ethanol consumption in vivo and its product, NO, is a potent regulator of mitochondrial respiration 2) this is associated with increased tyrosine nitration-a marker of RNS 3) NO, in contrast, inhibits cytochrome c release from mitochondria, whereas RNS such as peroxynitrite, promotes release of this pro-apoptotic factor 4) chronic ethanol consumption leads to greater sensitivity of the hepatocyte to hypoxic stress. These data have led to the hypothesis that a critical mechanism contributing to alcohol hepatotoxicity is through NO-dependent modification of mitochondrial function. This concept will be tested by pursuit of the following Specific Aims in wild type and INOS knock out mice consuming ethanol: 1. Determine the effects of increased NO by chronic alcohol consumption on mitochondrial respiration, antioxidant capacity and ROS/RNS formation. 2. Determine the effect of chronic alcohol consumption on cytochrome c release and mitochondrial protein modification in isolated organelle and hepatocytes. 3. Determine the NO-dependent effects on mitochondrial protein synthesis and the response of hepatocytes to hypoxic stress after chronic consumption of ethanol.