CHRONIC ETHANOL CONSUMPTION AND MITOCHONDRIAL DNA DAMAGE

长期乙醇消耗与线粒体 DNA 损伤

• 批准号: 6509026
• 负责人: ALAN CAHILL
• 金额: $ 21.44万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-19 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6509026
• 关键词: DNA damage; adduct; age difference; alcoholic beverage consumption; alcoholism /alcohol abuse; ethanol; laboratory rat; mitochondrial DNA; oxidative stress; pathologic process; phosphorylation

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.

描述：（改编自研究者的摘要）建议 研究长期乙醇消耗导致的假设 线粒体DNA氧化损伤增加，衰老可能会增加线粒体DNA的氧化损伤 肝线粒体对乙醇引起的 mtDNA 缺陷的敏感性 体内平衡。已发表的数据表明，长期饲喂乙醇具有深远的影响 对大鼠肝线粒体代谢功能的影响。乙醇摄入量 导致氧化磷酸化减少，结构异常 线粒体和线粒体产生的活性氧水平升高 物种。研究人员之前的研究已经证实，从长期来看 暴露会导致 mtDNA 氧化损伤增加，表现为增加 8-羟基脱氧鸟苷 (8-OHdG) 加合物的水平。这些研究已 扩展显示 2 个月大的动物维持 Lieber-DeCarli 饮食 一年内 mtDNA 含量减少 40%，而 mtDNA 含量增加 3 倍 8-OHdG 加合物形成。此外，单链断裂和 还观察到线粒体DNA的缺失。最近，短期、慢性乙醇 制定了喂养方案，用 Lieber-DeCarli 喂养 1 岁的大鼠 2个月的饮食，与饮食习惯改变无关的喂养期 幼年动物的 mtDNA 结构。初步结果表明，这些动物 与年轻人相比，mtDNA 损耗更大（大于 60%） 动物饲喂乙醇一年。这表明衰老会增加 肝线粒体对乙醇诱导的 mtDNA 改变的敏感性 体内平衡。拟议的研究将（a）充分描述新喂养方式的特征 线粒体DNA含量、氧化损伤水平和 呼吸链复合物的活性； (b) 调查影响 氧化损伤对老年人线粒体DNA降解和修复过程的影响 动物，以阐明其背后的生化机制 乙醇引起 mtDNA 耗竭； (c) 研究乙醇的作用和 线粒体DNA缺失形成过程中的活性氧； (d) 调查 线粒体DNA含量减少对线粒体产生的影响 转录本和电子传递链复合物的活性； （五） 研究mtDNA结构改变在形成中的作用 与酒精性肝病（ALD）相关的病理病变；和 (f) 研究乙醇消耗对肝脏 mtDNA 结构的影响 人类酗酒者。我们对 mtDNA 在发病机制中作用的理解 这些深入分析将增强对酒精性肝病的认识。