Sterile Hepatic Inflammation

描述(由申请人提供)： 项目摘要/摘要病理性肝细胞死亡导致无菌炎症反应(SIR)，从而放大最初的肝损伤。SIR是多种疾病损伤的重要组成部分，包括对乙酰氨基酚(APAP)肝毒性，以及酒精性和非酒精性脂肪性肝炎。导致肝脏无菌炎症的分子机制在很大程度上是未知的。假设。肝脏无菌炎症的发展有两个信号要求：信号1)哺乳动物核酸激活TLR7和9导致前IL-1b和前IL-18上调；信号2)激活炎症体和caspapse-1以裂解前IL-1b和前IL-18，并分泌活性细胞因子。为了研究这些问题，我们使用了APAP肝毒性的小鼠模型，并表明：i)完全APAP肝毒性需要IL-1b和IL-18。Ii)TLR7和TLR9的激活是肝脏上调前IL-1b和前IL-18转录本和完全APAP肝毒性所必需的。3)凋亡肝细胞DNA可激活肝窦内皮细胞表面TLR9，引起肝损伤。4)炎症小体的组成成分(NLRP3、ASC、caspase-1)是APAP完全肝毒性所必需的。基于这一背景，我们提出了以下目标：1：确定哺乳动物核酸与TLR7和9之间的相互作用，从而导致前IL-1b和前IL-18上调。1A)检测来自健康、坏死和凋亡的肝细胞的单链RNA以及核和线粒体DNA是否能上调肝细胞群体中的前IL-1b和前IL-18。1b)测试是否需要TLR7和9信令来实现1a中看到的效果。1c)确定TLR7和TLR9导致前IL-1b和前IL-18上调的信号通路。1d)测试TLR7和TLR9是否足以或需要激活炎症小体。2：确定NLRP3炎症体的激活机制。2a)确定ATP和尿酸一钠(MSU)在肝细胞群中炎性小体激活中的作用。2B)确定Pannexin通道在APAP诱导的肝脏SIR中的作用。2C)确定体内MSU在APAP诱导的肝脏SIR中的作用。 公共卫生相关性： 项目简介药物中毒引起的慢性肝病、酒精性脂肪性肝炎(ASH)、非酒精性肝炎(NASH)、丙型肝炎和乙型肝炎在退伍军人中的比例过高。这是由于药物滥用、糖尿病以及接触针头和血液制品的发生率较高。这导致了由于疲劳、黄疸、脚踝肿胀和瘙痒而导致的非常高的发病率。此外，这还会导致因肝硬变、肝细胞癌和肝功能衰竭而导致的死亡率增加。目前，这些肝病还没有有效的治疗方法。这是因为我们对肝脏炎症和损伤是如何在这些情况下开始的了解非常少。我们建议确定TLR和炎症体通路中的分子，这是启动肝脏炎症和损伤过程所必需的。因此，从这个项目中获得的知识将直接导致为这些疾病设计合理的治疗方法。

DESCRIPTION (provided by applicant): Project Summary/Abstract Pathological hepatocyte death results in a sterile inflammatory response (SIR) which amplifies the original liver injury. The SIR is an important component of injury in a wide range of diseases including acetaminophen (APAP) hepatotoxicity, as well as alcoholic and non-alcoholic steatohepatitis. The molecular mechanisms responsible for sterile inflammation in the liver are largely unknown. Hypothesis. There is a two signal requirement for the development of sterile inflammation in the liver: Signal 1) Activation of TLR 7 and 9 by mammalian nucleic acids resulting in up-regulation of pro-IL-1b and pro-IL-18 and signal 2) Activation of the inflammasome and caspapse-1 for cleavage of pro-IL-1b and pro-IL-18, and secretion of active cytokines. To examine these issues, we have used the mouse model of APAP hepatotoxicity and show that: i) IL- 1b and IL-18 are required for full APAP hepatotoxicity. ii) Activation of TLR7 and 9 is required for up-regulation of pro-IL-1b and pro-IL-18 transcripts in the liver and full APAP hepatotoxicity. iii) DNA from apoptotic hepatocytes can activate TLR9 on sinusoidal endothelial cells, and cause liver injury. iv) Components of the inflammasome (NLRP3, ASC, caspase-1) are required for full APAP hepatotoxicity. Based on this background we propose the following objectives: 1: Identify the interactions between mammalian nucleic acids and TLR 7 and 9 which result in up- regulation of pro-IL-1b and pro-lL-18. 1a) Test if ssRNA and nuclear and mitochondrial DNA from healthy, necrotic and apoptotic hepatocytes can up-regulate pro-IL-1b and pro-lL-18 in liver cell populations. 1b) Test if TLR 7 and 9 signaling is required for the effects seen in 1a. 1c) Identify the signaling pathways fromTLR7 and TLR9 which result in up-regulation of pro-IL-1b and pro-IL-18. 1d) Test if TLR7 and 9 are sufficient or required for inflammasome activation. 2: Identify the mechanisms of activation of the NLRP3 inflammasome. 2a) Determine the role of ATP and monosodium urate (MSU) in inflammasome activation in liver cell populations. 2b) Determine the role of the pannexin channel in-vivo in the APAP induced hepatic SIR. 2c) Determine the role of MSU in-vivo in the APAP induced hepatic SIR. PUBLIC HEALTH RELEVANCE: Project Narrative Chronic liver disease due to drug toxicity, alcoholic steatohepatitis (ASH), non-alcoholic hepatitis (NASH), hepatitis C and B are over-represented in the veteran population. This is due to a higher incidence of substance abuse, diabetes and exposure to needle sticks and blood products. This results in a very high degree of morbidity due to fatigue, jaundice, ankle swelling and pruritis. In addition this also results in increased mortality due to cirrhosis, hepatocellular cancer as well as liver failure. Currently there are no effective treatments these liver diseases. This is due to the fact that we have a very poor understanding of how liver inflammation and injury start in these conditions. We propose to identify the molecules in the TLR and inflammasome pathways, which are required to start the process of liver inflammation and injury. The knowledge gained from this project will therefore directly result in designing rational therapies for these conditions.