Ethanol Hepatotoxicity and NO-Dependent Mitochondrial Dysfunction

描述（由申请人提供）：乙醇引起的缺氧增加导致肝毒性，其机制尚不清楚。线粒体功能障碍和相关活性氧和氮（ROS/RNS）的形成似乎是肝脏中酒精暴露的结果。我们假设乙醇依赖性缺氧与一氧化氮（NO）与线粒体呼吸链的相互作用有关，这已得到先前资助期进行的研究的支持。在这一竞争性更新中，我们建立在以下发现的基础上：a)对NO依赖的线粒体呼吸抑制的敏感性增强发生在暴露于酒精的早期；b)这种反应在缺乏诱导NO合成酶同型型的小鼠中消失；c)这些变化与线粒体蛋白质组的变化以及蛋白质和线粒体DNA的氧化修饰有关。这些数据导致了一种假设，即酒精肝毒性通过增加线粒体功能障碍而加剧，而线粒体靶向抗氧化剂将改善这些影响。这一概念将通过追求以下具体目标来检验：确定线粒体靶向抗氧化剂（MTA）对酒精依赖性肝毒性和缺氧发展的影响。2：确定MTA对慢性酒精依赖性线粒体蛋白活性变化、NO对呼吸链抑制的敏感性和mtDNA损伤的影响。3：确定MTA对线粒体蛋白质组乙醇依赖性修饰的影响。该项目将通过确定慢性酒精中毒导致肝损伤的机制来促进公共卫生。此外，还将测试一种新型药物的可能性，这种药物可以直接作用于细胞中产生能量的部分，以逆转或防止酒精的这些毒性作用。

DESCRIPTION (provided by applicant): Increased hypoxia in response to ethanol contributes to hepatotoxicity through mechanisms that are not understood in detail. Mitochondrial dysfunction and the associated formation of reactive oxygen and nitrogen species (ROS/RNS) appear to be a consequence of alcohol exposure in the liver. We hypothesized that ethanol-dependent hypoxia involved a contribution from the nitric oxide (NO) interaction with the mitochondrial respiratory chain, and this has been supported by studies undertaken in the previous funding period. In this competing renewal, we build upon these findings that demonstrate a) enhanced sensitivity to the NO-dependent inhibition of mitochondrial respiration occurs early on exposure to alcohol b) this response is ablated in mice lacking the inducible NO synthase isoform c) these changes are associated with changes in the mitochondrial proteome and oxidative modification of proteins and mitochondrial DNA. These data have led to the hypothesis that alcohol hepatotoxicity is exacerbated through increased mitochondrial dysfunction and these effects will be ameliorated by mitochondrially targeted antioxidants. This concept will be tested by pursuit of the following Specific Aims: 1. Determine the effect of mitochondrially targeted antioxidants (MTA) on the development of alcohol-dependent hepatoxicity and hypoxia. 2: Determine the effects of MTA on the chronic alcohol-dependent changes in activity of mitochondrial proteins, sensitivity to inhibition of the respiratory chain by NO and damage to mtDNA. 3: Determine the effects of MTA on the ethanol dependent modifications of the mitochondrial proteome. This project will contribute to public health through defining the mechanisms that lead to the liver damage that occurs in response to chronic alcoholism. In addition, the possibility of using a new class of drugs directed to the parts of the cell that produce energy to reverse or prevent these toxic effects of alcohol will be tested.