Mitochondrial depolarization, mitophagy, and mitochondrial DAMPs in ALD

ALD 中的线粒体去极化、线粒体自噬和线粒体 DAMP

• 批准号: 10736591
• 负责人: John J Lemasters
• 金额: $ 53.9万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10736591
• 关键词: Abdomen; Acetaldehyde; Acute; Adenine Nucleotides; Alcohol consumption; Alcoholic Liver Diseases; Alcohols; Aldehydes; Attention; Binding; Biogenesis; Cholesterol; Chronic; Cirrhosis; Collagen; Collagen Fiber; Conditioned Culture Media; Cyclic GMP; Dangerousness; Development; Diet; Disease; DsRed; Dyes; Ethanol; Ethanol Metabolism; Fibrosis; Fluorescence; Generations; Hepatic; Hepatic Stellate Cell; Hepatocyte; Human; In Vitro; Kinetics; Label; Liver; Liver Fibrosis; Liver Mitochondria; Liver diseases; Membrane; Membrane Potentials; Metabolic; Mitochondria; Mitochondrial DNA; Mitochondrial Swelling; Molecular; Movement; Mus; NADH; Oxygen Consumption; PINK1 gene; Parkin; Pathway interactions; Pattern; Permeability; Process; Proliferating; Proteins; Protons; Rattus; Recovery; Respiration; Role; Rupture; Signal Transduction; Source; Steatohepatitis; Swelling; TLR9 gene; Therapeutic; Time; UCP2 protein; Ubiquitination; Work; aldehyde dehydrogenases; end stage liver disease; fluorophore; functional restoration; in vivo; inhibitor; liver inflammation; liver injury; mitochondrial autophagy; mortality; multiphoton imaging; oxidation; prevent; receptor; response; restoration; stellate cell; success; synergism

Alcohol-associated liver disease (ALD) is the leading cause of liver-related mortality. How ethanol (EtOH) damages the liver remains poorly understood, and therapies are lacking or unproven. A better understanding of the mechanisms by which the liver handles, processes, and responds to EtOH is needed to develop strategies to avoid and treat the dangerous hepatic ramifications of alcohol, particularly fibrosis and cirrhosis. EtOH consumption produces a swift increase in alcohol metabolism (SIAM) that is associated with a commensurate increase of mitochondrial respiration. Our work reveals reversible hepatic mitochondrial depolarization (mtDepo), increased mitophagic burden, and release of mitochondrial DNA (mtDNA) in mice after EtOH treatment, that precedes hepatic steatohepatitis and fibrosis. Here, we build on these findings to characterize the signals, pathways, and mechanisms of 1) onset and recovery from EtOH-induced mtDepo, 2) mtDepo- induced mitophagy, and 3) stellate cell activation and fibrosis downstream of mtDepo. Overall, we hypothesize that mtDepo is an adaptive response stimulating more rapid mitochondrial NADH oxidation to supply NAD+ required for EtOH metabolism, but chronically, mtDepo becomes maladaptive, causing disordered mitophagy and release of mitochondrial damage-associated molecular patterns (mtDAMPs) like mtDNA, leading ultimately to hepatic end stage liver disease. In Specific Aim 1, we will characterize the mechanisms of onset and recovery of EtOH-induced mtDepo, specifically the role of opening and closing of different proton leak pathways in inducing mtDepo and of mitochondrial biogenesis to restore functional mitochondria after EtOH is metabolically eliminated. In Specific Aim 2, we will characterize the manner of mitophagy after EtOH treatment. Specifically, we will determine if mitophagy initiated by EtOH-induced mtDepo involves the classical PINK1/Parkin ubiquitination pathway, is triggered by mitochondrial swelling leading to inner membrane herniation through a ruptured outer membrane with release of mtDNA as observed in preliminary work, or both. In Specific Aim 3, we will determine pathways by which mtDAMPs (like mtDNA) (possibly in synergism with acetaldehyde generated from hepatic EtOH metabolism) elicit a profibrogenic response in stellate cells with particular attention of the role of mtDNA-sensing toll-like receptor-9 (TLR9) whose deficiency decreases alcohol-induced liver injury. Together, these aims will increase our understanding of mechanisms underlying both the onset and recovery from mtDepo and how mtDepo-induced dysregulated mitophagy leads to mtDAMP release causing stellate cell activation and ultimately hepatic fibrosis. The findings of this project will allow development of new mechanism-based therapeutics to treat and prevent alcoholic liver disease.

酒精相关性肝病（ALD）是肝脏相关死亡的主要原因。乙醇（EtOH）如何 对肝脏的损害仍知之甚少，并且缺乏或未经证实的治疗方法。更好地理解 需要了解肝脏处理、加工和响应乙醇的机制来制定策略 避免和治疗酒精对肝脏的危险后果，特别是纤维化和肝硬化。乙醇 饮酒会导致酒精代谢（SIAM）迅速增加，这与相应的酒精代谢有关 线粒体呼吸增加。我们的工作揭示了可逆的肝线粒体去极化 (mtDepo)，EtOH 后小鼠线粒体自噬负担增加和线粒体 DNA (mtDNA) 释放 在脂肪性肝炎和纤维化之前进行治疗。在这里，我们根据这些发现来描述 1) EtOH 诱导的 mtDepo 的发生和恢复的信号、途径和机制，2) mtDepo- 诱导线粒体自噬，3) mtDepo 下游星状细胞活化和纤维化。总的来说，我们假设 mtDepo 是一种适应性反应，刺激线粒体 NADH 氧化更快地供应 NAD+ 是 EtOH 代谢所必需的，但长期来看，mtDepo 会变得适应不良，导致紊乱 线粒体自噬和线粒体损伤相关分子模式 (mtDAMP) 的释放，例如 mtDNA， 最终导致肝终末期肝病。在具体目标 1 中，我们将描述机制的特征 EtOH 诱导的 mtDepo 的起始和恢复，特别是不同质子的打开和关闭的作用 EtOH 后诱导 mtDepo 和线粒体生物发生以恢复功能线粒体的渗漏途径 被代谢消除。在具体目标 2 中，我们将描述 EtOH 后线粒体自噬的方式 治疗。具体来说，我们将确定 EtOH 诱导的 mtDepo 引发的线粒体自噬是否涉及经典的 PINK1/Parkin 泛素化途径，由线粒体肿胀触发，导致内膜突出 通过破裂的外膜并释放线粒体DNA（如初步工作中所观察到的），或两者兼而有之。具体来说 目标 3，我们将确定 mtDAMP（如 mtDNA）（可能与乙醛协同作用）的途径 由肝脏乙醇代谢产生）在星状细胞中引起促纤维化反应，特别是 关注 mtDNA 感应 Toll 样受体 9 (TLR9​​) 的作用，其缺陷会降低酒精诱导的酒精中毒 肝损伤。总之，这些目标将增加我们对发病机制的理解 mtDepo 的恢复以及 mtDepo 诱导的线粒体自噬失调如何导致 mtDAMP 释放 引起星状细胞活化并最终导致肝纤维化。该项目的研究结果将允许 开发新的基于机制的疗法来治疗和预防酒精性肝病。