CHRONIC ETHANOL CONSUMPTION AND MITOCHONDRIAL DNA DAMAGE

描述：（改编自研究者摘要）拟 研究慢性乙醇消耗导致 线粒体DNA的氧化损伤增加，衰老可能会增加 乙醇引起线粒体DNA缺陷对肝线粒体易感性的影响 体内平衡已发表的数据表明，长期乙醇喂养有深刻的影响， 对大鼠肝线粒体代谢功能的影响。乙醇摄入 导致氧化磷酸化降低，结构异常 线粒体和脑内产生的活性氧水平升高 物种研究者先前的研究已经确定， 暴露导致线粒体DNA氧化损伤增加，这反映在 8-羟基脱氧鸟苷（8-OHdG）加合物的水平。这些研究 扩展以显示2个月大的动物维持Lieber-DeCarli饮食 一年后，线粒体DNA含量减少了40%， 8-OHdG加合物形成。此外，单链断裂和 还观察到mtDNA的缺失。最近，一种短期的慢性乙醇 制定了喂养方案，其中1岁大的大鼠喂食Lieber-DeCarli 饮食2个月，喂养期，这是不相关的改变， 年轻动物的mtDNA结构初步结果显示这些动物 表现出更大的线粒体DNA消耗（大于60%）比年轻人 动物喂食乙醇1年。这表明衰老会增加 乙醇诱导肝线粒体DNA改变对肝线粒体的敏感性 体内平衡拟议的研究将（a）充分描述新的喂养方式 线粒体DNA含量、氧化损伤水平和 呼吸链复合物的活性;（B）研究 氧化损伤对老年人线粒体DNA降解和修复过程的影响 动物，以阐明背后的生化机制（S） 乙醇引起的mtDNA耗竭;（c）研究乙醇和 活性氧在mtDNA缺失形成中的作用;（d）研究 线粒体DNA含量降低对线粒体DNA合成的影响 转录物和电子传递链复合物的活性;（e） 研究线粒体DNA结构改变在形成 与酒精性肝病（ALD）相关的病理学病变;和（f） 研究酒精消耗对肝线粒体DNA结构的影响， 人类酒鬼我们对线粒体DNA在肿瘤发病机制中的作用的理解 酒精性肝病将通过这些深入的分析得到加强。

DESCRIPTION: (Adapted from the Investigator's Abstract) It is proposed to investigate the hypothesis that chronic ethanol consumption results in increased oxidative damage to mtDNA and that aging may increase the susceptibility of liver mitochondria to ethanol-elicited defects in mtDNA homeostasis. Published data show that long-term ethanol feeding has a profound effect on the metabolic functioning of rat liver mitochondria. Ethanol intake results in decreased oxidative phosphorylation, structurally abnormal mitochondria and elevated levels of mitochondrially-produced reactive oxygen species. Previous studies by the investigator have established that long term exposure causes increased oxidative damage to mtDNA, as reflected by increased levels of 8-hydroxydeoxyguanosine (8-OHdG) adducts. These studies have been extended to show that 2 month old animals maintained on the Lieber-DeCarli diet for one year exhibit a 40% depletion in mtDNA content and a 3-fold increase in 8-OHdG adduct formation. In addition, increases in single strand breaks and deletions of mtDNA are also observed. Recently, a short term, chronic ethanol feeding regimen was developed where 1 year old rats are fed the Lieber-DeCarli diet for 2 months, a feeding period that is not associated with alterations in mtDNA structure in young animals. Preliminary results show that these animals exhibit a greater mtDNA depletion (greater than 60%) than that seen in young animals fed ethanol for 1 year. This suggests that aging increases the susceptibility of hepatic mitochondria to ethanol-induced alterations in mtDNA homeostasis. The proposed studies will (a) fully characterize the new feeding model with regard to mtDNA content, levels of oxidative damage and the activities of respiratory chain complexes; (b) investigate the effect of oxidative damage on the processes of mtDNA degradation and repair in old animals, in order to elucidate the biochemical mechanism(s) behind the ethanol-elicited mtDNA depletion; (c) investigate the role of ethanol and reactive oxygen species in the formation of mtDNA deletions; (d) investigate the effect of decreased mtDNA content on the production of mitochondrial transcripts and the activities of electron transport chain complexes; (e) investigate the role of mtDNA structural alterations in the formation of pathological lesions associated with alcoholic liver disease (ALD); and (f) investigate the effects of ethanol consumption on hepatic mtDNA structure in human alcoholics. Our understanding of the role of mtDNA in the pathogenesis of alcoholic liver disease will be enhanced by these in-depth analyses.