Aldehyde Dehydrogenase-2 as a Drug Target for Cholestatic Liver Fibrosis

醛脱氢酶 2 作为胆汁淤积性肝纤维化的药物靶点

• 批准号: 9174034
• 负责人: Hereward John Clfford Wimborne
• 金额: $ 4.02万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2017-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9174034
• 关键词: 4 hydroxynonenal; Adverse event; Affect; Aldehydes; Animal Model; Apoptosis; Attenuated; Cause of Death; Cholestasis; Chronic; Cirrhosis; Collagen; Complex; Data; Deposition; Development; Drug Metabolic Detoxication; Drug Targeting; Effector Cell; Enzymes; Epigenetic Process; Ethanol toxicity; Extracellular Signal Regulated Kinases; Fibrosis; Generations; Hepatic Stellate Cell; Histology; Hydroxyproline; Image; Inflammation; Injury; Lead; Ligation; Lipid Inclusion; Lipid Peroxidation; Lipid Peroxides; Liver; Liver Failure; Liver Fibrosis; Malondialdehyde; Mediator of activation protein; Mentors; Metabolism; MicroRNAs; Microscopy; Mitochondria; Mitogen-Activated Protein Kinases; Morphology; Multicellular Process; Mus; Necrosis; Nuclear; Pharmaceutical Preparations; Phosphorylation; Pilot Projects; Platelet-Derived Growth Factor; Play; Procollagen; Proteins; Reactive Oxygen Species; Recovery; Role; Signal Transduction; Signaling Molecule; Smooth Muscle Actin Staining Method; Testing; Therapeutic; Time; Transforming Growth Factor beta; Transforming Growth Factors; Transplantation; Virus Diseases; Vitamin A; aldehyde dehydrogenases; bile duct; chronic liver disease; connective tissue growth factor; diphenyleneiodonium; in vivo; knock-down; liver inflammation; liver injury; liver transplantation; mouse model; new therapeutic target; novel; p65; prevent; protein expression; public health relevance; response; second harmonic; small molecule; success

 DESCRIPTION (provided by applicant): Fibrotic transformation of the liver is a major cause of death worldwide. The generation of reactive oxygen species (ROS) is a typical feature of chronic liver disease, causing protein damage and lipid peroxidation and leading to formation of toxic aldehydes. Mitochondrial aldehyde dehydrogenase-2 (ALDH2) detoxifies these aldehydes. My recent pilot study showed that Alda-1, a novel small-molecule activator of ALDH2, decreased fibrosis after bile duct ligation (BDL). Accordingly, I seek to validate ALDH2 as a drug target to decrease fibrosis by detoxification of toxic aldehydes. I hypothesize that activation of ALDH2 aids in the detoxification of aldehydes and decreases activation of hepatic stellate cells, thereby suppressing fibrosis and promoting recovery. Success of this study will identify a novel therapeutic target against fibrosis for development of much needed antifibrotic drugs to treat hepatic fibrosis/cirrhosis. I will test this hypothesis through two Specific Aims. 1) Elucidate the anti-fibrotic role of ALDH2 in a mouse model of cholestatic injury. The role of toxic aldehydes in fibrosis remains unclear. Therefore, I will explore whether toxic aldehydes play a critical role in liver fibrosis and if ALDH2 activation attenuates fibrosis after BDL. I will assess time- dependent changes of toxic aldehydes generation (4-hydroxynonenal [4-HNE] and malondialdehyde [MDA]), ALDH2 expression/activity, and fibrotic markers and signals (e.g., alpha-smooth muscle actin [α-SMA], TGFβ- 1, PDGF, Smad 2/3, ERK, and NF-κB p65 subunit), and epigenetic control by microRNAs. I will directly image HSC activation and procollagen deposition using intravital multiphoton/second harmonic generation (SHG) microscopy. Fibrotic liver injury is a complex, multicellular process, so I will also determine the effect of ALDH2 activation and deficiency on hepatocellular injury (necrosis and apoptosis) and inflammation after BDL. I expect that ALDH2-deficiency will increase toxic aldehydes and exacerbate hepatic injury and fibrotic activation, whereas ALDH2 activation will mitigate these adverse events. I expect that these studies will validate ALDH2 as a new drug target against ROS-associated liver fibrosis. 2) Determine whether ALDH2 activation inhibits activation of hepatic stellate cells (HSC) and/or causes reversion of activated HSCs to a quiescent state. In addition to my pilot study, previous studies show that aldehydes activate cultured HSCs. I will assess whether ALDH2 activation in HSCs prevents/decreases activation by both exogenous and endogenous aldehydes at early stages and promotes reversion of activated HSCs at later stages. I will verify through ALDH2 knockdown that the effect of Alda-1 is ALDH2 dependent. I expect: 1) Toxic aldehydes will accumulate as HSCs become activated in culture; 2) ALDH2 knockdown will increase, whereas ALDH2 activation by Alda- 1 will delay/decrease spontaneous and exogenous aldehyde-induced HSC activation; and 3) Late administration of Alda-1 will blunt and even reverse HSC activation. These data serve to demonstrate a direct relationship between aldehyde metabolism and activation of HSCs, the primary fibrotic effector cells.

 描述(由申请人提供)：肝脏纤维化转化是世界范围内死亡的主要原因。活性氧(ROS)的产生是慢性肝病的典型特征，可导致蛋白质损伤和脂质过氧化，并导致有毒醛的形成。线粒体乙醛脱氢酶-2(ALDH2)可使这些醛脱毒。我最近的初步研究表明，ALDA-1，一种新型的ALDH2小分子激活剂，可以减少胆管结扎(BDL)后的纤维化。因此，我试图验证ALDH2作为一种通过解毒有毒醛来减少纤维化的药物靶点。我推测ALDH2的激活有助于醛的解毒，减少肝星状细胞的激活，从而抑制纤维化，促进恢复。这项研究的成功将为开发治疗肝纤维化/肝硬变的急需的抗纤维化药物确定一个新的抗纤维化治疗靶点。我将通过两个具体目标来检验这一假设。1)澄清 ALDH2在胆汁淤积性损伤小鼠模型中的抗纤维化作用。有毒醛在纤维化中的作用尚不清楚。因此，我将探讨有毒的醛是否在 肝纤维化和If ALDH2激活可减轻BDL后的纤维化。我将评估与时间相关的 毒性醛的生成(4-羟基壬烯醛和丙二醛)、ALDH2的表达/活性、纤维化标志物和信号(如α-平滑肌肌动蛋白[α-SMA]、转化生长因子β-1、PDGF、Smad2/3、ERK和NF-κB p65亚单位)的变化，以及MicroRNAs对表观遗传的调控。我将使用活体多光子/二次谐波(SHG)显微镜直接成像HSC的激活和前胶原沉积。纤维化肝损伤是一个复杂的、多细胞的过程，因此我还将研究ALDH2的激活和缺失对BDL后肝细胞损伤(坏死和凋亡)和炎症的影响。我预计ALDH2缺乏会增加有毒的醛，加剧肝损伤和纤维化激活，而ALDH2的激活将减轻这些不良事件。我预计这些研究将证实ALDH2是一种对抗ROS相关性肝纤维化的新药靶点。2)确定ALDH2激活是否抑制肝星状细胞(HSC)的激活和/或使激活的HSC回复到静止状态。除了我的初步研究外，以前的研究表明，醛可以激活培养的HSC。我将评估HSCs中ALDH2的激活是否在早期阻止/减少外源和内源性醛的激活，并在后期促进激活的HSCs的逆转。我将通过ALDH2基因敲除来验证ALDA-1的作用是依赖于ALDH2的。我预计：1)当HSC在培养中被激活时，有毒的醛将会积累；2)ALDH2基因敲除将增加，而ALDH2被ALDA-1激活将延迟/降低自发和外源性醛诱导的HSC激活；以及3)晚期给药将钝化甚至逆转HSC的激活。这些数据证明了醛代谢和肝干细胞激活之间的直接关系，肝干细胞是主要的纤维化效应细胞。