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） 对肝脏损害的了解仍然很少，缺乏或未经证实的治疗方法。更好地了解 需要肝脏处理、加工和响应乙醇的机制来制定策略 以避免和治疗酒精引起的危险的肝脏后果，特别是纤维化和肝硬化。EtOH 酒精消耗会导致酒精代谢（SIAM）的迅速增加，这与相应的酒精消耗有关。 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），增加线粒体吞噬负荷，并释放线粒体DNA（mtDNA） 在肝性脂肪性肝炎和纤维化之前进行治疗。在这里，我们以这些发现为基础， 1）EtOH诱导的mtDepo的发作和恢复，2）mtDepo的信号，途径和机制， 诱导的线粒体自噬，和3）mtDepo下游的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，刺激更快的线粒体NADH氧化， 乙醇代谢所需的NAD+，但长期而言，mtDepo变得适应不良， 线粒体自噬和线粒体损伤相关分子模式（mtDAMP）如mtDNA的释放， 最终导致肝终末期肝病。在具体目标1中，我们将描述 EtOH诱导的mtDepo的发生和恢复，特别是不同质子的开放和关闭的作用， 诱导mtDepo和线粒体生物合成的泄漏途径以在EtOH后恢复功能性线粒体 都被代谢掉了在具体目标2中，我们将表征EtOH后的线粒体自噬方式 治疗具体来说，我们将确定EtOH诱导的mtDepo启动的线粒体自噬是否涉及经典的线粒体自噬。 PINK 1/Parkin泛素化途径，由线粒体肿胀触发，导致内膜疝 通过破裂的外膜释放线粒体DNA，如在初步工作中观察到的，或两者兼而有之。在特定 目的3，我们将确定线粒体DAMPs（如mtDNA）（可能与乙醛协同作用）的途径， 由肝EtOH代谢产生）在星状细胞中引起促纤维化反应， 注意线粒体DNA敏感Toll样受体9（TLR 9）的作用，其缺陷减少酒精诱导的 肝损伤总之，这些目标将增加我们对发病机制的理解， 以及mtDepo诱导的线粒体自噬失调如何导致mtDAMP释放 导致星状细胞活化并最终导致肝纤维化。该项目的研究结果将使 开发新的基于机制的治疗方法来治疗和预防酒精性肝病。