Dichotomous Roles of Thrombin in Acetaminophen Hepatotoxicity

凝血酶在对乙酰氨基酚肝毒性中的二分作用

基本信息

批准号：
8490364
负责人：
Robert Andrew Roth
金额：
$ 31.17万
依托单位：
MICHIGAN STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-30 至 2015-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8490364
关键词：
Acetaminophen Acute Liver Failure Antifibrinolytic Agents Blood coagulation Cells Cessation of life Coagulation Process Coculture Techniques Data Dependency Deposition Dose Endothelium Event Fibrin Fibrinogen Fibrinolysis Generations Genetic Glutathione Hemorrhage Hepatocyte Hepatotoxicity Human Hypoxia Hypoxia Inducible Factor In Vitro Inflammation Mediators Injury Integral Membrane Protein Interleukin-1 beta Interleukins Intervention Knock-out Lead Link Liver Liver Failure Mediating Mediator of activation protein Metabolic Metabolism Mus N-acetyl-4-benzoquinoneimine Nitric Oxide Overdose Oxidative Stress PAR-1 Receptor Pathogenesis Pathologic Patients Peptide Hydrolases Pharmaceutical Preparations Phase Plasma Proteins Plasminogen Activator Inhibitor 1 Play Production Proteins Research Design Role Series System Technology Testing Therapeutic Intervention Thrombin Thrombin Receptor Thromboplastin Time Tissues Toxic effect Tumor Necrosis Factor-alpha acetaminophen overdose base biological systems cytokine hepatic necrosis improved in vivo injured intrahepatic liver injury novel novel strategies prevent protein expression public health relevance research study stem transcription factor

项目摘要

DESCRIPTION (provided by applicant): Overdose with acetaminophen (APAP) is the most common cause of acute liver failure in humans. Metabolic bioactivation of APAP initiates a cascade of events that causes hepatocellular necrosis, and it is during this progression phase when antidotal therapy is most likely to be successful. In human patients, coagulation cascade activation and thrombin generation accompanies the progression of APAP hepatotoxicity. In APAP- treated mice, tissue factor (TF) activates the coagulation cascade, resulting in activation of the thrombin receptor, protease-activated receptor-1 (PAR-1), and in the deposition of fibrin in liver. Preliminary results suggest that coagulation system activation has dichotomous roles in APAP hepatotoxicity. TF-dependent thrombin generation and stimulation of PAR-1 appear to contribute to the early progression of liver damage, since deficiency in TF or PAR-1 reduces early APAP-induced hepatocellular injury. Generation of nitric oxide and of cytokines such as tumor necrosis factor-alpha and interleukin 1-beta are associated with early progression of APAP hepatotoxicity, and PAR-1 activation of nonparenchymal cells in other tissues has been shown to stimulate production of each of these factors. Conversely, thrombin-mediated fibrin deposition limits later hepatocellular injury and hemorrhage. The deposition of fibrin is enhanced by the antifibrinolytic activity of plasminogen activator inhibitor-1 (PAI-1), a plasma protein the expression of which is induced by the transcription factor, hypoxia inducible factor-1alpha (HIF-1a). Based on our preliminary data, we hypothesize that APAP overdose results in TF-dependent production of thrombin, which contributes to the early progression of liver injury by activating PAR-1, but also limits hemorrhage and hepatocellular necrosis progression by generating fibrin. This hypothesis will be tested in mice in a series of experiments in vivo and in vitro employing parenchymal and nonparenchymal liver cells and using genetic approaches including novel mice generated using conditional knockout, Cre-LoxP technology, as well as appropriate pharmacological interventions. Aim 1 will explore the importance of TF expressed by hepatocytes and hepatocyte-derived procoagulant microparticles in thrombin generation, and the role of decreased glutathione in TF activation during APAP toxicity. Aim 2 will determine the role of PAR-1 activation on nonparenchymal cells in the expression of factors associated with the pathogenesis APAP-induced liver injury. The final aim will focus on the injury-limiting influence of fibrin clots and role of HIF-1a-mediated expression of PAI-1 in fibrin deposition in liver. Elucidating mechanisms by which APAP-induced liver injury progresses is essential for defining novel strategies to prevent liver failure in patients and for the general understanding of the pathogenesis of drug-induced liver injury.

描述（由申请人提供）：用对乙酰氨基酚（APAP）过量是人类急性肝衰竭的最常见原因。 APAP的代谢生物激活引发了导致肝细胞坏死的一系列级联事件，正是在此进展阶段，当抗原疗法最有可能成功。在人类患者中，凝血级联激活和凝血酶产生伴随着APAP肝毒性的进展。在APAP处理的小鼠中，组织因子（TF）激活凝血级联反应，从而激活凝血酶受体，蛋白酶激活的受体1（PAR-1）以及在肝脏中纤维蛋白的沉积中。初步结果表明，凝血系统的激活在APAP肝毒性中具有二分法。 TF依赖性凝血酶的产生和PAR-1刺激似乎有助于肝损伤的早期进展，因为TF或PAR-1的缺乏会减少早期APAP诱导的肝细胞损伤。一氧化氮和细胞因子（例如肿瘤坏死因子-Alpha和白介素1-β）的产生与APAP肝毒性的早期进展有关，并且已证明其他组织中非正质细胞的PAR-1激活可刺激这些因素的产生。相反，凝血酶介导的纤维蛋白沉积限制后来肝细胞损伤和出血。纤维蛋白的沉积通过纤维蛋白抑制剂1（PAI-1）的抗纤维蛋白分解活性增强，血浆蛋白是由转录因子，低氧诱导因子-1alpha（HIF-1A）诱导的表达。基于我们的初步数据，我们假设APAP过量导致凝血酶的TF依赖性产生，这通过激活PAR-1来促进肝损伤的早期进展，但也限制了通过产生纤维蛋白的出血和肝细胞性坏死进展。该假设将在小鼠的体内和实质性肝细胞的一系列实验和体外进行测试，并使用遗传方法，包括使用条件敲除，CRE-LOXP技术产生的新小鼠，以及适当的药理干预措施。 AIM 1将探讨肝素产生中肝细胞和肝细胞衍生的proc凝微粒表达的TF的重要性，以及在APAP毒性过程中谷胱甘肽降低在TF激活中的作用。 AIM 2将确定PAR-1激活对非肾小球细胞的作用在与发病机理APAP诱导的肝损伤相关的因子表达中的作用。最终目标将集中于纤维蛋白凝块的损伤影响以及HIF-1A介导的PAI-1在肝蛋白沉积中的表达的作用。阐明APAP诱导的肝损伤进展的机制对于定义预防患者肝衰竭的新型策略以及对药物引起的肝损伤发病机理的一般理解至关重要。