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（由申请方提供）：肝损伤由病毒性肝炎感染、其他感染（如登革热）、化学品（如乙醇）和生物毒素引起。原发性肝细胞损伤是由先天免疫系统介导的免疫病理过程，但其机制尚不清楚。这部分是因为缺血再灌注和CCl 4给药等实验模型同时影响许多肝细胞类型。为了阐明肝脏免疫病理学的机制，我们建立了一个新的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，然后施用白喉毒素导致肝损伤。有趋化因子基因的快速上调和混合骨髓流入，与血清丙氨酸氨基转移酶（ALT）的急剧升高相一致。我们发现了两个惊人的现象。首先，病理学是通过Toll样受体-3（TLR-3）介导的，这表明RNA是重要的分子触发器的假设。第二，当我们分离和隔离不同的肝细胞亚群时，先天免疫反应在肝细胞中最为显著。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性免疫反应的原动力。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可能是相关的。在具体目标2中，我们解剖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去唾液酸糖蛋白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，但在具体目标3中，我们使用B型肝炎病毒诱导的免疫病理学实验模型，检验了RNA和TLR 3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TLR 3介导的肝损伤机制，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，我们使用白喉毒素引起伤害，这是一种潜在的生物威胁。改善白喉毒素诱导的细胞损伤的新方法将在生物攻击事件中保护群体方面具有重要价值。其次，特定目标1和3中的新实验使用重组RNA酶融合蛋白，该蛋白经遗传工程改造用作人类治疗剂，并且已经处于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，那么就有一条直接的途径将这一发现转化为临床医学。