Pathobiology of Liver Injury

肝损伤的病理学

• 批准号: 10292719
• 负责人: Harmeet Malhi
• 金额: $ 40.99万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-23 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10292719
• 关键词: Acetylation; Address; Americas; Applications Grants; Attenuated; Binding; Binding Proteins; Cell Communication; Cell Line; Cells; Communication; Complex; Data; Diet; Disease; Disease Progression; EP300 gene; Economic Burden; Endoribonucleases; Enhancers; Enzymes; Epigenetic Process; Factor X; Fatty Liver; Fatty acid glycerol esters; Generations; Genetic Transcription; Goals; Grant; Hepatic; Hepatocyte; Histones; Immune; In Vitro; Inflammation; Inflammatory; Inositol; Interruption; Knock-out; Kupffer Cells; Leukocytes; Link; Lipids; Liver; Liver diseases; Lysine; Mediating; Mediator of activation protein; Molecular; Molecular Genetics; Mouse Strains; Mus; Obesity; Pathogenesis; Pattern; Pharmacology; Play; Process; Proteomics; Research; Role; S100A11 gene; Signal Transduction; Sorting - Cell Movement; Stress; Testing; Transplantation; United States; Up-Regulation; base; biological adaptation to stress; career; cell injury; chronic liver disease; druggable target; endoplasmic reticulum stress; experimental study; extracellular vesicles; genetic approach; granulocyte; in vitro Model; in vivo Model; inhibitor/antagonist; insight; intrahepatic; liver inflammation; liver injury; macrophage; monocyte; mortality; nonalcoholic steatohepatitis; novel; particle; receptor; receptor expression; receptor for advanced glycation endproducts; recruit; therapeutic target; transcription factor; vesicular release

PROJECT ABSTRACT. My long term career objective is to define the mechanisms of liver inflammation in nonalcoholic steatohepatitis (NASH), the most-prevalent chronic liver disease in the United States of America. NASH is characterized by endoplasmic reticulum (ER) stress, which results in release of proinflammatory extracellular vesicles (EVs) from lipid overloaded (lipotoxic) hepatocytes. The contribution of recruited monocyte-derived macrophages (MDMs) to the intrahepatic macrophage (IHM) pool increases in NASH and the recruited MDMs play a pivotal role in inflammation. The current proposal examines the mechanistic link between hepatocyte-derived EVs and specific MDM subsets. In preliminary studies we have identified that activation of the lipotoxic ER stress activated endoribonuclease, inositol requiring enzyme 1 alpha (IRE1α) and its target transcription factor X-box binding protein 1 (XBP1), upregulates the expression of S100A11. This upregulation of S100A11 is associated with activating, histone 3 lysine 27, acetylation in the enhancer region of S100A11. Lipotoxic hepatocytes release S100A11 containing EVs (S100A11-EVs). S100A11-EVs activate macrophage receptor for advanced glycation endproducts (RAGE) signaling. Hepatocellular expression of S100A11 and MDM expression of RAGE are upregulated in NASH. Silencing S100A11 decreases MDM- associated hepatic inflammation in NASH. Based on these original preliminary data, we have formulated the CENTRAL HYPOTHESIS that lipotoxic hepatocytes release S100A11-EVs which activate a subset of proinflammatory RAGE expressing IHMs promoting NASH pathogenesis. Therefore, the goals of this proposal are to understand: i) how S100A11-EVs are released by hepatocytes; ii) how RAGE is activated by lipotoxic EVs in a subset of macrophages; and iii) can hepatic inflammation be attenuated by inhibiting S100A11-EV-RAGE signaling? The proposed experiments will employ complementary in vitro and in vivo models of lipotoxicity and NASH, and pharmacological, molecular and genetic approaches to address three integrated hypotheses. First we will directly test the hypothesis that lipotoxic hepatocytes release S100A11- EVs a) by XBP1 driven transcriptional upregulation of S100A11 by binding to and recruiting histone acetylating factors to an enhancer region, and b) by selective cargo sorting of S100A11 into lipotoxic EVs. Second we will directly test the hypothesis that RAGE is activated in a subset of macrophages by lipotoxic EVs a) by generating multivalent signal competent RAGE oligomers, and b) leads to the accumulation of a subset of proinflammatory RAGE expressing macrophages in the liver. Third we will directly test the hypothesis that interrupting S100A11-EV induced RAGE activation attenuates murine NASH a) by reducing the release of S100A11-EVs, and b) when macrophage RAGE is deleted. This R01 grant application will yield mechanistic insights into hepatocyte-to-macrophage crosstalk in NASH, thus identifying potentially druggable targets, e.g., inhibitors of S100A11 or RAGE.

项目摘要。我的长期职业目标是定义肝脏炎症的机制 非酒精性脂肪性肝炎（NASH），美国最贫乏的慢性肝病。 NASH的特征是内质网（ER）应激，这导致促炎的释放 脂质过载（脂肪毒性）肝细胞的细胞外蔬菜（EV）。招募的贡献 纳什和 招募的MDM在炎症中起关键作用。当前的提案考试机械链接 在肝细胞衍生的电动汽车和特定的MDM子集之间。在初步研究中，我们已经确定 激活脂肪毒性ER应激激活的内丁核酸酶，肌醇，需要酶1α（IRE1α）和 其目标转录因子X-box结合蛋白1（XBP1）上调S100A11的表达。这 S100A11的上调与激活，组蛋白3赖氨酸27，增强剂区域的乙酰化有关 S100A11。脂肪毒性肝细胞释放含有EV的S100A11（S100A11-EVS）。 S100A11-EVS激活 巨噬细胞受体用于晚期糖基化最终产物（RAGE）信号传导。肝细胞表达 NASH中更新了S100A11和MDM的愤怒表达。沉默S100A11逐渐下降MDM- 纳什相关的肝炎。基于这些原始的初步数据，我们已经制定了 中心假设是脂肪毒性肝细胞释放S100A11-EVS，该evs激活了一个子集 表达IHM的促炎愤怒，促进NASH发病机理。因此，目标的目标 提案要理解：i）肝细胞如何释放S100A11-EV； ii）如何激活愤怒 巨噬细胞子集中的脂肪毒性电动汽车； iii）可以通过抑制来减弱肝发炎 S100A11-EV-RAGE信号传导？提出的实验将在体外和体内采用完整性 脂肪毒性和NASH的模型，以及药物，分子和遗传方法，以解决三个 综合假设。首先，我们将直接检验脂肪毒性肝细胞释放S100A11-的假设。 EVS a）通过XBP1驱动的S100A11的转录上调和募集组蛋白乙酰化。 增强剂区域的因素，b）通过选择性货物将S100A11的选择性分类为脂肪毒性电动汽车。第二我们会 直接检验以下假设：lipototoxic evs a）在巨噬细胞中激活愤怒的假设 产生多价信号胜任的愤怒低聚物，b）导致一部分的积累 促炎的促进愤怒在肝脏中表达巨噬细胞。第三，我们将直接检验以下假设 中断S100A11-EV引起的愤怒激活减少了鼠Nash a）减少释放 S100A11-EV，b）当巨噬细胞愤怒被删除时。此R01赠款申请将产生机理 对纳什中肝细胞到巨噬细胞串扰的洞察力，从而确定了潜在的可吸毒靶标，例如 S100A11或愤怒的抑制剂。