Innate Immune Response to Hepatocyte Death

对肝细胞死亡的先天免疫反应

• 批准号: 9199394
• 负责人: Ian NICHOLAS Crispe
• 金额: $ 52.13万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-10 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9199394
• 关键词: Address; Adverse effects; Affect; Alanine; Alcohol consumption; Asialoglycoprotein Receptor; Biological; CD8-Positive T-Lymphocytes; Cell Death; Cells; Cessation of life; Chemicals; Chimeric Proteins; Clinical Medicine; Complementary DNA; Data; Dengue; Diphtheria Toxin; Disease; Employee Strikes; Ethanol; Event; Experimental Models; Gene Transduction Agent; Genes; Genetic Engineering; Hepatitis; Hepatitis B; Hepatitis C; Hepatocyte; Human; Immune; Immune response; Impairment; Infection; Injection of therapeutic agent; Injury; Injury to Liver; Innate Immune Response; Innate Immune System; Intervention; Ischemia; Literature; Liver; Liver diseases; Mediating; Methods; Modeling; Molecular; Mus; Myelogenous; Natural Immunity; Organ Transplantation; Pathogenesis; Pathology; Pathway interactions; Pattern; Persons; Phagocytes; Phagocytosis; Phase II Clinical Trials; Physiological; Poison; Population; Publishing; RNA; RNA Degradation; Recombinants; Reperfusion Therapy; Ribonucleases; Role; Sepsis; Serum; Signal Transduction; Small Interfering RNA; TLR3 gene; Testing; Therapeutic Agents; Tissues; Toxin; Transgenes; Translating; Up-Regulation; Viral hepatitis; Virus; Work; acute liver injury; base; cell injury; cell type; chemokine; diphtheria toxin receptor; experimental study; extracellular; granulocyte; immunopathology; in vivo; injured; insight; killings; liver infection; liver injury; macrophage; mouse model; novel; prevent; public health relevance; receptor; response; selective expression; sensor; transcriptome sequencing; vector

 DESCRIPTION (provided by applicant): Liver injury results from viral hepatitis infection, from other infections such as Dengue Fever, from chemicals such as ethanol, and from biological toxins. Primary hepatocellular injury in complicated by immunopathology mediated by the innate immune system, but the mechanisms are poorly understood. This is partly because experimental models such as ischemia-reperfusion and CCl4 administration impact on many liver cell types simultaneously. To clarify the mechanisms of liver immunopathology we have created a novel model to study the consequences of hepatocyte death. A gene therapy vector is used to express the Diphtheria Toxin Receptor specifically in mouse hepatocytes, then administration of Diphtheria Toxin results in liver injury. There is rapid up-regulation of chemokine genes and a mixed myeloid influx, coinciding with a sharp elevation in serum Alanine Aminotransaminase (ALT). We made two striking observations. First, the pathology is mediated via Toll-Like Receptor-3 (TLR-3), suggesting the hypothesis that RNA is the important molecular trigger. Second, when we dissociate and isolate different subsets of liver cells, the innate immune response is by far most dramatic in hepatocytes. This gives us a second hypothesis that the hepatocytes are the prime movers in sensing hepatocellular injury and orchestrating the innate immune response. In Specific Aim 1 we directly address the RNA DAMP through experiments to formally prove that RNA is the signal, and to identify what form(s) of RNA are likely to be relevant. In Specific Aim 2, we dissect the liver injury to determine the role of different forms of hepatocyte death, test whether hepatocytes directly recognize the TLR-3 mediated signal, and then test the hypothesis that the capacity of hepatocytes to take up their dead neighbors through the AsialoGylcoprotein Receptor is critical for such recognition. So far we have focused our preliminary work on the hepatocyte-specific Diphtheria Toxin model, but in Specific Aim 3 we test the hypothesis that RNA- and TLR3-dependent liver injury occurs in a more physiological context, using an experimental model of the immunopathology induced by Hepatitis B Virus. These experiments will give insight into the mechanism of an under-explored mechanism of liver injury, mediated through TLR3, and test its wider applicability. Two aspects of the proposed work enhance its global significance. First, we provoke injury using Diphtheria Toxin, which is a potential biological threat. New ways to ameliorate Diphtheria Toxin-induced cell damage will be of great value in protecting the population in the event of a biological attack Secondly, new experiments in Specific Aims 1 and 3 use a recombinant RNase fusion protein that is genetically engineered for use as a human therapeutic agent, and is already in Phase II clinical trials. This means that if the in vivo degradation of RNA in fact ameliorates liver immunopathology, there is an immediate pathway to translate this discovery to clinical medicine.

 描述（由申请人提供）：肝损伤由病毒性肝炎感染、登革热等其他感染、乙醇等化学物质以及生物毒素引起。原发性肝细胞损伤由先天免疫系统介导的免疫病理学复杂化，但其机制尚不清楚。部分原因是缺血再灌注和 CCl4 给药等实验模型同时影响多种肝细胞类型。为了阐明肝脏免疫病理学机制，我们创建了一种新模型来研究肝细胞死亡的后果。使用基因治疗载体在小鼠肝细胞中特异性表达白喉毒素受体，然后施用白喉毒素会导致肝损伤。趋化因子基因快速上调和混合髓细胞流入，同时血清丙氨酸氨基转氨酶 (ALT) 急剧升高。我们做出了两个惊人的观察。首先，病理学是通过 Toll 样受体 3 (TLR-3) 介导的，这表明 RNA 是重要的分子触发因素的假设。其次，当我们解离和分离不同的肝细胞亚群时，先天免疫反应在肝细胞中是迄今为止最显着的。这给了我们第二个假设，即肝细胞是感知肝细胞损伤和协调先天免疫反应的原动力。在具体目标 1 中，我们通过实验直接解决 RNA DAMP，以正式证明 RNA 是信号，并确定哪些形式的 RNA 可能相关。在具体目标 2 中，我们剖析了肝损伤以确定不同形式的肝细胞死亡的作用，测试肝细胞是否直接识别 TLR-3 介导的信号，然后测试肝细胞通过 AsialoGylco Protein 受体吸收其死亡邻居的能力对于这种识别至关重要的假设。到目前为止，我们的初步工作集中在肝细胞特异性白喉毒素模型上，但在特定目标 3 中，我们使用乙型肝炎病毒诱导的免疫病理学实验模型检验了 RNA 和 TLR3 依赖性肝损伤发生在更生理背景下的假设。这些实验将深入了解通过 TLR3 介导的尚未探索的肝损伤机制，并测试其更广泛的适用性。拟议工作的两个方面增强了其全球意义。首先，我们使用白喉毒素造成伤害，这是一种潜在的生物威胁。改善白喉毒素引起的细胞损伤的新方法对于在生物攻击时保护人群具有重要价值。 其次，具体目标 1 和 3 中的新实验使用了重组 RNase 融合蛋白，该蛋白经过基因工程改造，可用作人类治疗剂，并且已处于 II 期临床试验中。这意味着，如果 RNA 的体内降解实际上改善了肝脏免疫病理学，那么就有一个直接途径可以将这一发现转化为临床医学。