Lipotoxicity and Liver Inflammation

脂毒性和肝脏炎症

• 批准号: 10337075
• 负责人: Samar Ibrahim
• 金额: $ 35.78万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-15 至 2024-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10337075
• 关键词: Adhesions; Adoptive Transfer; Affinity; Anti-Inflammatory Agents; Attenuated; Binding; Biochemical; Biogenesis; Biological; Biology; Cell Adhesion Inhibition; Cell Adhesion Molecules; Cell Communication; Cell model; Cell surface; Cells; Childhood; Choline; Cytoskeleton; Data; Development; Diet; Disease; Encapsulated; Endothelial Cells; Endothelium; Exposure to; Flow Cytometry; Functional disorder; GTPase-Activating Proteins; Goals; Hepatic; Hepatocyte; Home; Human; In Vitro; Infiltration; Inflammation; Inflammatory Response; Injury; Integrin Inhibition; Integrins; Isotope Labeling; Leukocytes; Ligands; Link; Lipids; Liver; Liver diseases; Mediating; Mediator of activation protein; Modeling; Molecular; Molecular Conformation; Molecular Profiling; Mus; Nonesterified Fatty Acids; Obesity; Pathogenesis; Pathway interactions; Pharmacology; Positron-Emission Tomography; Proteome; Public Health; Publishing; Research; Role; Scaffolding Protein; Signal Pathway; Signal Transduction; Sterility; Stress; Surface; Testing; Therapeutic Intervention; Vascular Cell Adhesion Molecule-1; base; experimental study; extracellular vesicles; hepatocyte injury; inhibitor; innovation; insight; liver inflammation; liver injury; macrophage; member; microfluidic technology; monocyte; mouse model; nanomedicine; nanoscale; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; novel therapeutic intervention; p38 Mitogen Activated Protein Kinase; prevent; recruit; therapeutic target; trafficking; vesicular release

PROJECT SUMMARY Overall Objectives of this proposal are to define mechanisms linking hepatocyte injury during lipotoxicity with hepatic inflammation in nonalcoholic steatohepatitis (NASH). NASH is the most common pediatric liver disease characterized by abundant circulating saturated free fatty acids (SFAs), along with hepatocyte lipotoxicity and monocyte-derived macrophage mediated liver inflammation. Hepatocyte lipotoxicity and liver injury are, in part, induced by SFAs and their intracellular metabolite lysophosphatidyl choline (LPC). However, cellular and molecular mechanisms linking hepatocyte lipotoxicity to liver inflammation are not completely understood. Emerging data implicate extracellular vesicles (EVs) released during hepatocyte lipotoxic stress in liver inflammation. In published and preliminary experiments, we have discovered that, lipotoxic hepatocytes release a large number of proinflammatory EVs; these EVs are enriched with the adhesion molecule integrin β1 (ITGβ1) and promote monocytes adhesion to liver sinusoidal endothelial cells (LSECs) in vitro. We also demonstrated that the expression of ITGβ1 ligand, vascular cell adhesion molecule (VCAM) 1, on LSECs is increased during lipotoxicity. Based on these novel observations, we have formulated the CENTRAL HYPOTHESIS that lipotoxic hepatocytes release ITGβ1-enriched EVs that recruit and retain monocyte in the liver promoting inflammation. We will employ current biochemical and cell biological approaches that include microfluidic technology, Nanoscale flow cytometry, and 89Zirconium isotopically labelled EVs visualized with positron emission tomography (PET) scan to test this hypothesis. Our independent SPECIFIC AIMS will test three integrated hypotheses. First, we will demonstrate that hepatocyte lipotoxicity induces an active conformation switch of ITGβ1, enhancing its endocytic trafficking and release into EVs. Second, we will define the mechanism of increased VCAM1 expression during lipotoxicity. We will also directly test the hypothesis that lipotoxic hepatocyte-derived EVs mediate monocytes adhesion to LSECs, through ITGβ1-VCAM1 binding interaction, in vitro by using microfluidic technology. Third, using a mouse model of NASH, we will test the hypothesis that pharmacological inhibition of integrin β1 or conditional deletion of endothelial VCAM1 is protective against liver inflammation. We will also demonstrate that adoptively-transferred lipotoxic hepatocyte- derived EVs home to the LSECs of recipient mice through their high affinity integrin β1cargo. We have established the requisite cell and mouse models to study lipotoxicity, integrin signaling and EV biology. This proposal is technically and conceptually innovative, as it seeks to integrate the molecular mechanisms underlying hepatocyte injury, integrin activation and trafficking with liver inflammation, and links hepatic pathophysiology with nanomedicine. This research has the potential to identify new therapeutic strategies, namely integrin and VCAM1 inhibitors, to prevent or reverse liver injury and inflammation in human NASH.

项目摘要 该提案的总体目标是定义与脂肪毒性期间肝细胞损伤联系起来的机制 非酒精性脂肪性肝炎（NASH）中的肝炎炎症。纳什是最常见的小儿肝病 以丰富的循环饱和游离脂肪酸（SFA）以及肝细胞脂毒性和 单核细胞衍生的巨噬细胞介导的肝脏注射。肝细胞脂肪毒性和肝损伤部分是 由SFA及其细胞内代谢物溶磷脂酰胆碱（LPC）诱导。但是，细胞和 将肝细胞脂肪毒性与肝脏炎症联系起来的分子机制尚不完全了解。 新兴数据暗示肝细胞脂肪毒性应激期间释放的细胞外蔬菜（EV） 炎。在发布和初步实验中，我们发现，脂肪毒性肝细胞 释放大量促炎性电动汽车；这些电动汽车富含粘合分子整合素 β1（ITGβ1）在体外促进对肝正弦内皮细胞（LSEC）粘合的单核细胞。我们也是 证明了lsecs上的ITGβ1配体的表达，血管细胞粘合分子（VCAM）1的表达 在脂毒性期间增加。基于这些新颖的观察，我们制定了中央 假设脂肪毒性肝细胞释放了富含ITGβ1的电动汽车，该电动汽车募集并保留单核细胞 肝脏促进炎症。我们将采用当前的生化和细胞生物学方法，包括 微流体技术，纳米级流式细胞仪和89zirconium同位素标记的EVS可视化 正电子发射断层扫描（PET）扫描以检验该假设。我们独立的特定目标将测试 三个综合假设。首先，我们将证明肝细胞脂肪毒性会影响活性 ITGβ1的构象转换，增强其内吞运输并释放到EV中。第二，我们将定义 脂肪毒性期间VCAM1表达增加的机制。我们还将直接检验假设 通过ITGβ1-VCAM1结合，脂肪毒性肝细胞衍生的EV介导了LSEC的单核细胞粘附于LSECS 通过使用微流体技术在体外相互作用。第三，使用NASH的鼠标模型，我们将测试 假设整联蛋白β1的药物抑制或内皮VCAM1的条件缺失为 防止肝脏炎症。我们还将证明自适应转移的脂肪毒性肝细胞 - 通过高亲和力整合蛋白β1Cargo衍生的EV源自受体小鼠的LSEC。我们有 建立了必要的细胞和小鼠模型，以研究脂肪毒性，整合素信号传导和EV生物学。这 提案在技术上和概念上都是创新的，因为它试图整合分子机制 潜在的肝细胞损伤，整联蛋白激活和肝脏感染的运输，并连接肝 纳米医学的病理生理学。这项研究有可能确定新的治疗策略， 即整联蛋白和VCAM1抑制剂，以预防或反向人类NASH肝损伤和注射。