Novel determinants of fibrinogen pro-repair activity in acetaminophen-induced liver toxicity

对乙酰氨基酚诱导的肝毒性中纤维蛋白原修复活性的新决定因素

• 批准号: 10585920
• 负责人: James P Luyendyk
• 金额: $ 41.72万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10585920
• 关键词: Acetaminophen; Acetylcysteine; Acute; Acute Liver Failure; Afibrinogenemia; Air; Analgesics; Biochemistry; Blood coagulation; Cell Culture System; Chemicals; Coagulation Process; Complex; Custom; Data; Defect; Deposition; Enzymes; Exposure to; Factor XIII; Fibrin; Fibrinogen; Gene Expression; Glutaminase; Goals; Health; Hemorrhage; Hemostatic function; Hepatic; Hepatotoxicity; Hospital Costs; Human; In Vitro; Injury; Integrin Binding; Integrins; Ligands; Link; Liver; Liver Failure; Liver diseases; Macrophage; Macrophage Activation; Mediating; Modification; Molecular; Mus; Mutation; Outcome; Overdose; Pathway interactions; Patient-Focused Outcomes; Patients; Phagocytes; Pharmaceutical Preparations; Polymers; Process; Property; Proteins; Research; Risk; Role; Structure; Testing; Therapeutic; Thrombin; Tissues; Toxic Hepatitis; Toxicant exposure; United States; Variant; acetaminophen overdose; acetaminophen-induced liver injury; acute liver injury; acute toxicity; clotting enzyme; crosslink; design; gene repair; improved; in vitro activity; in vivo; injured; injury and repair; intrahepatic; liver injury; liver repair; mouse model; novel; novel therapeutics; programs; repair function; repaired; response; therapeutic target; thrombotic; thrombotic complications; toxicant; transglutaminase 2

PROJECT SUMMARY The leading cause of acute liver injury and acute liver failure in the United States is hepatotoxicity caused by overdose of the pain medication acetaminophen (APAP). Nearly 50% of patients presenting with APAP- induced liver injury require costly hospitalization, and the efficacy of available treatments (i.e., N- acetylcysteine) is very limited for patients presenting well after APAP overdose. APAP overdose patients would benefit most from treatments that maximize liver repair pathways, such as proe-pr air macrophage activation. We recently discovered a remarkable pathway of liver repair following APAP hepatotoxicity whereby the clotting protein fibrin(ogen), deposited in the injured liver of both humans and mice, engages β2 integrins and directs local pro-repair macrophage activity. The fibrin(ogen)-β2 integrin interaction is carefully regulated and acquired by modifications of fibrin(ogen) structure. Defining the mechanisms whereby fibrin(ogen) is converted to a β2 integrin ligand that elicits pro-repair macrophage activity in liver injury is critical, as this could uncover novel putative therapeutic targets to improve liver repair pathways in patients with severe hepatotoxicity or acute liver failure. Our strong preliminary studies suggest that, in contrast to the current paradigm, hepatic fibrin(ogen) accumulation caused by acute toxicity is independent of blood coagulation activity. The central hypothesis framing these studies is that liver injury stimulates coagulation-independent cross-linking of fibrin(ogen) by tissue transglutaminase-2 (TGM2) to form a novel fibrin(ogen) complex that drives macrophage- mediated liver repair. Our approach includes genetically-modified mice lacking specific fibrin(ogen) cross- linking enzymes, mice expressing fibrin(ogen) proteins with specific functional mutations, application of a coagulation-insensitive fibrin(ogen) as a putative pro-repair therapeutic, a unique cell culture system to examine primary macrophage activation by unique molecular forms of fibrin(ogen), and analysis of fibrin(ogen) deposits in livers of human patients with acute liver failure. The investigative team comprises experts in toxic liver injury and repair, coagulation and fibrin(ogen) biochemistry/function, and mouse modeling of liver disease. In our proposed studies we will: (Aim 1) Identify the mechanism whereby APAP-induced liver injury stimulates hepatic deposition of repair-promoting cross-linked fibrin(ogen); (Aim 2) Determine the role of fibrin(ogen) hemostatic function in repair of the APAP-injured liver; and (Aim 3) Determine the mechanism whereby fibrin(ogen) cross-linking drives pro-repair macrophage activity in vitro. The expected outcome of these Specific Aims is discovery of entirely novel mechanisms linking unique structural modification of the clotting protein fibrin(ogen) with macrophage-mediated liver repair. Identifying these mechanisms could pinpoint putative targets (e.g., TGM2, β2 integrin-fibrin(ogen) interaction), and novel agents, such as fibrinogen tailored to be pro-repair and free of thrombotic risk. Indeed, such major advances would provide entirely novel specific therapies to improve liver repair that would greatly improve patient outcomes.

项目摘要 美国急性肝损伤和急性肝衰竭的主要原因是肝毒性。 止痛药对乙酰氨基酚（APAP）的过量。在患有APAP的患者中，近50％ 诱发肝损伤需要昂贵的住院和可用治疗的效率（即N- 对于APAP过量后出现的患者，乙酰半胱氨酸）非常有限。 APAP过量患者会 从最大化肝脏修复途径的治疗中受益，例如Proe-pr空气巨噬细胞激活。 最近，我们发现了APAP肝毒性后的肝脏修复的出色途径 凝结蛋白纤维蛋白（OGEN），沉积在人类和小鼠的受伤肝脏中，参与β2整联蛋白和 指导局部亲修复巨噬细胞活性。纤维蛋白（OGEN）-β2整联蛋白相互作用仔细调节，并且 通过纤维蛋白（OGEN）结构的修饰获取。定义将纤维蛋白（OGEN）转换的机制 对于β2整联蛋白配体引起肝损伤中的巨噬细胞活性至关重要，因为这可能会发现 新型假定的治疗靶标，以改善严重肝毒性或 急性肝衰竭。我们的强大初步研究表明，与当前的范式相比 由急性毒性引起的纤维蛋白（OGEN）积累与血液凝血活性无关。中央 假设构架这些研究是肝损伤刺激了与凝血无关的交联 组织转谷氨酰胺酶-2（TGM2）的纤维蛋白（OGEN）形成一种新型的纤维蛋白（OGEN）复合物，该复合物驱动巨噬细胞 - 介导的肝修复。我们的方法包括一般修饰的小鼠，缺乏特定的纤维蛋白（OGEN）横蛋白 连接酶，表达纤维蛋白（OGEN）蛋白与特定功能突变的小鼠的应用 凝结不敏感的纤维蛋白（OGEN）作为推定的促培养疗法，一种独特的细胞培养系统 通过独特的分子形式的纤维蛋白（OGE）（OGEN）检查原代巨噬细胞激活，并分析纤维蛋白（OGEN） 急性肝衰竭患者生计中的沉积物。调查团队包括有毒的专家 肝损伤和修复，凝结和纤维蛋白（OGEN）生物化学/功能以及肝病的小鼠建模。 在我们提出的研究中，我们将：（目标1）确定APAP诱导的肝损伤刺激的机制 修复促进的交联纤维蛋白（OGEN）的肝脏沉积； （AIM 2）确定纤维蛋白（OGEN）的作用 修复APAP受伤的肝脏的止血功能； （目标3）确定机制 纤维蛋白（OGEN）交联驱动体外促进巨噬细胞活性。这些特定的预期结果 目的是发现完全新颖的机制，与服装蛋白的独特结构修饰联系在一起 纤维蛋白（OGEN）具有巨噬细胞介导的肝修复。确定这些机制可以确定推定的 靶标（例如TGM2，β2整联蛋白 - 纤维蛋白（OGE）相互作用）和新型剂，例如量身定制的纤维蛋白原 亲修改，没有血小板风险。确实，这样的主要进步将提供完全新颖的特定特定 改善肝脏维修的疗法将大大改善患者的预后。