IRAKM and Mincle in ALD

IRAKM 和 Mincle 在 ALD 中

• 批准号: 9067893
• 负责人: Xiaoxia Li
• 金额: $ 43.81万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2020-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9067893
• 关键词: Affect; Alcohol abuse; Alcoholic Liver Diseases; Alcohols; American; Animal Model; Biochemical; C Type Lectin Receptors; Cell Death; Cessation of life; Cirrhosis; Complex; Data; Development; Disease Progression; Dose; Ethanol; Family; Fibrosis; Foundations; Future; Genes; Genetic; Goals; Health; Hepatic; Hepatitis; Hepatocyte; IRAK1 gene; IRAK2 gene; IRAK3 gene; IRAK4 gene; Indium; Inflammation; Inflammatory; Inflammatory Response; Injury; Interleukin-1; Intestines; Kupffer Cells; Lead; Ligands; Link; Lipopolysaccharides; Liver; Liver Circulation; MAP3K7 gene; Mediating; Molecular; Morbidity - disease rate; Mus; Myeloid Cells; Pathogenesis; Pathway interactions; Patients; Permeability; Phosphotransferases; Post-Transcriptional Regulation; Prevention; Primary carcinoma of the liver cells; Production; Reporting; Research Project Grants; Role; Signal Transduction; Source; Stimulus; TLR4 gene; TNF gene; Testing; Therapeutic; Therapeutic Intervention; Time; Translations; Up-Regulation; Work; alcohol exposure; base; chemokine; cytokine; design; endoplasmic reticulum stress; extracellular; feeding; improved; injured; interest; macrophage; member; mitochondrial dysfunction; mortality; mouse model; pre-clinical; preclinical study; problem drinker; response; response to injury; sensor; stellate cell; upstream kinase

 DESCRIPTION (provided by applicant): Alcoholic liver disease (ALD) is a major source of alcohol-related morbidity and mortality. It is estimated that 10-15 percent of alcoholics develop fibrosis, cirrhosis and hepatocellular carcinoma. Inflammatory responses are critical contributors to disease progression. One important pathway to increased inflammation results from increased intestinal permeability and changes in bacterial microflora, resulting in activation of Toll-like receptor 4 (TLR4) on Kupffer cells. However, ethanol also directly injures hepatocytes; our preliminary data indicate that signals from injured hepatocytes are also critical to the activation of hepatic macrophages. The overall objective of this proposal is to investigate how TLR-dependent inflammatory responses, in combination with alcohol-induced hepatocellular injury, coordinately lead to pathogenesis of ALD. TLRs transduce their signals through the adaptor molecule MyD88 and members of the IL-1R-associated kinase (IRAK) family, including IRAK1, IRAK2, IRAKM and IRAK4. IRAK4, the upstream kinase, directly interacts with MyD88. While MyD88- IRAK4-IRAK1 mediates TAK1-dependent NFB activation, MyD88-IRAK4-IRAK2 is critical for post- transcriptional control. While IRAKM interacts with MyD88-IRAK4 to mediate a MEKK3-dependent second wave NFB activation, it interacts with IRAK2 to inhibit translation of cytokines and chemokines. Thus, IRAKM exerts an overall inhibitory effect on inflammatory responses. Surprisingly, we found IRAKM-deficient mice were protected from ethanol-induced liver injury. Array analysis led us to be interested in one particular TLR4-induced IRAKM-dependent gene, Mincle, a C-type lectin receptor, that senses non-homeostatic cell death, thereby inducing pro-inflammatory cytokine and chemokine production. Mincle expression was induced in liver of ALD patients and in mice after ethanol feeding in an IRAKM-dependent pathway. Further, Mincle-deficient mice were protected from ethanol-induced liver injury. Since Mincle is a sensor for cell death and its expression is IRAKM-dependent, we hypothesize that TLR-induced IRAKM-dependent Mincle up-regulation in Kupffer cells provides a critical link between alcohol-induced cell death and onset of inflammatory responses, contributing to the pathogenesis of ALD. To test this hypothesis, we propose the following Aims: Aim 1 Investigate the mechanism for TLR-mediated IRAKM-dependent pathway in ALD: we will investigate (1) The molecular mechanism for the TLR-MyD88-IRAKM-MEKK3-dependent pathway induced by low dose of TLR ligands; (2) The mechanism for the pathogenic role of the TLR-MyD88-IRAKM-MEKK3-dependent pathway in ALD. Aim 2 Investigate the mechanism by which Mincle-mediated signaling contributes to ALD: We will investigate (1) The molecular mechanism for Mincle-mediated inflammasome activation; (2) The cellular mechanism for the pathogenic role of the Mincle-dependent pathway in ALD. These combined molecular/cellular and pre-clinical studies will identify critical elements in the role of the TLR-IRAK-M-Mincle signaling in ALD, leading to improved therapeutics for prevention and treatment of ALD.

 描述(由申请人提供)：酒精性肝病(ALD)是与酒精相关的发病率和死亡率的主要来源。据估计，10%-15%的酗酒者会患上纤维化、肝硬化和肝细胞癌。炎症反应是疾病进展的关键因素。炎症增加的一个重要途径是肠道通透性增加和细菌菌群变化，导致库普弗细胞上Toll样受体4(TLR4)的激活。然而，乙醇也直接损伤肝细胞；我们的初步数据表明，来自受损肝细胞的信号也是激活肝巨噬细胞的关键。这项建议的总体目标是研究依赖TLR的炎症反应与酒精诱导的肝细胞损伤如何协同导致ALD的发病。TLRs通过接头分子MyD88和IL-1R相关激酶(IRAK)家族成员，包括IRAK1、IRAK2、IRAKM和IRAK4来传递信号。上游的IRAK4与MyD88直接相互作用。MyD88-IRAK4-IRAK1介导依赖于的核转录因子TakB的激活，而MyD88-IRAK4-IRAK2对转录后调控起关键作用。当IRAKM与MyD88-IRAK4相互作用以介导依赖于MEKK3的第二波NFB激活时，它与IRAK2相互作用以抑制细胞因子和趋化因子的翻译。因此，IRAKM对炎症反应具有整体抑制作用。令人惊讶的是，我们发现IRAKM缺陷小鼠可以免受乙醇诱导的肝损伤。阵列分析使我们对TLR4诱导的IRAKM依赖基因Mincle感兴趣，Mincle是一种C型凝集素受体，它感知非稳态细胞死亡，从而诱导促炎细胞因子和趋化因子的产生。在ALD患者的肝脏和酒精喂养后的小鼠肝脏中，Mincle的表达是以IRAKM依赖的途径诱导的。此外，Mincle缺乏的小鼠可以免受乙醇诱导的肝损伤。由于Mincle是细胞死亡的感受器，其表达是IRAKM依赖的，我们推测TLR诱导的Kupffer细胞IRAKM依赖的Mincle上调在酒精诱导的细胞死亡和炎症反应的发生之间起着关键的联系，从而参与ALD的发病。为了验证这一假说，我们提出了以下目标：目的1探讨TLR介导的IRAKM依赖通路在ALD中的作用机制：(1)小剂量TLR配体诱导的TLR-MyD88-IRAKM-MEKK3依赖通路的分子机制；(2)TLR-MyD88-IRAKM-MEKK3依赖通路在ALD发病中的作用机制。目的2探讨Mincle介导的信号转导在ALD中的作用机制：(1)Mincle介导的炎性小体激活的分子机制；(2)Mincle依赖通路在ALD中致病作用的细胞机制。这些结合的分子/细胞和临床前研究将确定TLR-IRAK-M-Mincle信号在ALD中所起作用的关键因素，从而改进ALD的预防和治疗方法。