VDAC in Ethanol and Aldehyde-Induced Mitochondrial Dysfunction

VDAC 在乙醇和醛引起的线粒体功能障碍中的作用

• 批准号: 8761184
• 负责人: John J Lemasters
• 金额: $ 33.64万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-15 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8761184
• 关键词: 4 hydroxynonenal; Acetaldehyde; Acute; Affect; Alcohol dehydrogenase; Alcoholic Liver Diseases; Aldehydes; Apoptosis; Cell Death; Cell Membrane Permeability; Cessation of life; Citrulline; Cyclic AMP-Dependent Protein Kinases; Cytochrome P-450 CYP2E1; Disease; Dose; Drug Metabolic Detoxication; Endotoxins; Ethanol; Ethanol Metabolism; Etiology; Event; Fat emulsion; Fatty Acids; Fatty Liver; Functional disorder; Generations; Health; Hepatocyte; Histopathology; In Vitro; Individual; Knock-out; Kupffer Cells; Lead; Ligands; Lipid Peroxidation; Lipids; Liver; Liver Mitochondria; Liver diseases; Malondialdehyde; Mediating; Metabolism; Mitochondria; Molecular Weight; Movement; Mus; N-terminal; Ornithine; Outer Mitochondrial Membrane; Oxidative Stress; Oxygen; Pathogenesis; Pathology; Pathway interactions; Permeability; Phosphotransferases; Prevention; Process; Protein Isoforms; Protein Kinase; Rattus; Respiration; Role; Signal Transduction; Small Interfering RNA; Steatohepatitis; Techniques; Tumor Necrosis Factor-alpha; Urea; VDAC1 gene; VDAC2 gene; VDAC3 gene; Vertebral column; Volatile Fatty Acids; Voltage-Dependent Anion Channel; adenylate kinase; alcohol effect; aldehyde dehydrogenases; base; catalase; cell killing; effective therapy; expectation; in vitro Model; in vivo; inhibitor/antagonist; knock-down; liver injury; mitochondrial dysfunction; mitochondrial membrane; nonalcoholic steatohepatitis; novel; oxidation; phosphorothioate; receptor; research study; respiratory; rhodamine dextran; solute; stress-activated protein kinase 1; toxicant; treatment strategy; uptake

DESCRIPTION (provided by applicant): Liver pathology in alcoholic liver disease (ALD), non-alcoholic steatohepatitis (NASH) and forms of toxicant-associated steatohepatitis (TASH) is indistinguishable. ALD pathogenesis may be related to generation of toxic acetaldehyde (AcAld), whereas NASH and TASH are associated with generation of malondialdehyde (MDA), 4-hydroxynonenal (HNE), chloracetaldehyde (ClAcAld) and others by lipid peroxidation and/or toxicant metabolism. With the major exceptions of oxygen and short chain fatty acids, all mitochondrial metabolites cross mitochondrial outer membranes (MOM) via open voltage dependent anion channels (VDAC). The central hypothesis of this project is that ethanol and aldehydes close VDAC, decrease permeability of MOM and suppress normal mitochondrial function. Such VDAC closure allows the selective and more rapid mitochondrial oxidation of toxic aldehydes, which permeate mitochondria freely. Although VDAC closure is adaptive in promoting aldehyde detoxification, VDAC closure may be maladaptive in promoting steatosis and lipotoxicity. Accordingly, we propose to: 1) Characterize the effects of ethanol and aldehydes on ureagenesis in cultured hepatocytes, since ureagenesis is a major energy-consuming process that is dependent on exchange of metabolites across mitochondrial membranes. We will characterize the effects of ethanol, AcAld, MDA, HNE, ClAcAld and other aldehydes on ureagenic respiration and outer membrane permeability with the expectation that exogenous aldehydes and AcAld formed by ethanol metabolism will cause dose-dependent inhibition of ureagenesis and a decrease of MOM permeability to low molecular weight (≤ 3 kDa) solutes. Follow-on experiments identify kinase pathways mediating VDAC closure. 2) Determine the contributions of the three individual VDAC isoforms to suppression of ureagenesis in hepatocytes by ethanol and aldehydes using phosphorothioate siRNA single and double knockout/knockdowns of the VDAC isoforms. 3) Evaluate the role of aldehydes, kinases and VDAC in steatosis and lipotoxicity in vitro and in vivo. In preliminary experiments, aldehyde promoted steatosis dependent on c-Jun N-terminal kinase (JNK) after incubation of hepatocytes with Intralipid and sensitized to tumor necrosis factor-α (TNFα)-dependent apoptosis. We will evaluate mechanisms underlying this cell killing and the role of specific VDAC isoforms in promoting both steatosis and cell death. ALD and NASH are widely prevalent diseases in the U.S. for which therapy is largely ineffective. Lack of effective therapy reflects our ignorance of the underlying etiologies. In particular, the basis for the identical histopathology of ALD, NASH and TASH is unknown. Aldehyde-dependent VDAC closure provides a shared mechanism for the underlying pathophysiology of these diseases, which will likely lead to better strategies for treatment and prevention.

描述（由适用提供）：酒精性肝病（ALD），非酒精性脂肪性肝炎（NASH）和与毒物相关的脂肪性肝炎（TASH）的形式是无法区分的。 ALD发病机理可能与有毒乙醛（ACALD）的产生有关，而Nash和Tash与产生丙二醛（MDA），4-羟基诺纳尔（HNE），氯乙醛醛（Clacalde）（Clacald）（Clacald）和其他有关脂质过氧化物过氧化和毒剂的毒剂和毒性和毒剂Metaborism有关。除氧气和短链脂肪酸外，所有线粒体代谢产物都通过开放电压依赖性阴离子通道（VDAC）交叉线粒体外膜（MOM）。该项目的中心假设是乙醇和醛接近VDAC，降低了MOM的渗透性并抑制正常的线粒体功能。这种VDAC闭合允许选择性，尽管VDAC闭合在促进醛中具有适应性，从而自由地渗透了线粒体。尽管VDAC闭合在促进醛排毒方面具有适应性，但VDAC闭合可能在促进脂肪变性和脂肪毒性方面可能是不良适应性的。据此，我们建议：1）表征乙醇和醛对培养的肝细胞中尿素发生的影响，因为尿素发生是一个主要的能量耗尽过程，依赖于跨线粒体膜的代谢物的交换。我们将表征乙醇，Acald，MDA，HNE，Clacald和其他醛对尿素呼吸和膜外膜通透性的影响，并期望由乙醇代​​谢形成外源性醛和Acald，而乙醇代谢会导致剂量依赖性抑制Momengens solecare use的溶液效率（均可缩短量）。后续实验确定了介导VDAC闭合的激酶途径。 2）确定使用磷酸硫酸磷酸siRNA的乙醇和醛单独的三种VDAC同工型对乙醇和醛在肝细胞中抑制尿素发生的贡献。 3）评估醛，激酶和VDAC在体外和体内脂肪毒性中的作用。在初步实验中，醛在培养肝素内孵育肝胞脂和对肿瘤坏死因子因子-α（TNFα）依赖性凋亡后促进了脂肪变性。我们将评估这种细胞杀伤的基础机制以及特定VDAC同工型在促进脂肪变性和细胞死亡中的作用。在美国，ALD和NASH是美国广泛普遍存在的疾病。缺乏有效的疗法反映了我们对潜在病因的无知。特别是，ALD，NASH和TASH相同的组织病理学的基础是未知的。依赖醛的VDAC闭合为这些疾病的潜在病理生理提供了共同的机制，这可能会导致更好的治疗和预防策略。