IRAKM and MINCLE in ALD

ALD 中的 IRAKM 和 MINCLE

• 批准号: 10750123
• 负责人: LAURA E. NAGY
• 金额: $ 60.22万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-17 至 2028-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10750123
• 关键词: Acute; Adrenal Cortex Hormones; Affect; Alcohol abuse; Alcoholic Hepatitis; Alcoholic Liver Diseases; Alcohols; American; Animal Model; Automobile Driving; Binding Proteins; Biogenesis; Biological Response Modifiers; C Type Lectin Receptors; CASP1 gene; Carbon Tetrachloride; Caspase; Cell Death; Chronic; Cirrhosis; Clinical; Collagen; Complex; Data; Deposition; Development; Disease; Disease Progression; Dose; Endotoxins; Ethanol; Family; Fibrosis; Foundations; Future; Genes; Glucosylceramides; HMGB1 gene; Hepatic; Hepatic Stellate Cell; Hepatitis; Hepatocyte; IL18 gene; IRAK3 gene; IRAK4 gene; Impairment; Inflammasome; Inflammation; Inflammatory; Inflammatory Response; Injury; Innate Immune Response; Interleukin-1; Interleukin-1 beta; Interruption; Intervention; Intestinal permeability; Kupffer Cells; Lead; Ligands; Link; Lipid Binding; Lipopolysaccharides; Liver; Liver Fibrosis; Liver diseases; Macrophage; Malignant Neoplasms; Mediating; Modeling; Molecular; Morbidity - disease rate; Mus; Nonlytic; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Peripheral Blood Mononuclear Cell; Play; Primary carcinoma of the liver cells; Production; Proteins; Reporting; Risk; Role; Serum; Serum amyloid A protein; Severity of illness; Signal Transduction; Spliceosomes; TLR4 gene; TNF gene; Testing; Therapeutic; Therapeutic Intervention; cell injury; cytokine; effective therapy; end stage liver disease; extracellular vesicles; feeding; fibrogenesis; hepatocellular injury; hepatocyte injury; liver function; liver inflammation; liver injury; member; microbiota; mortality; mouse model; novel; novel therapeutic intervention; pharmacologic; programs; rational design; response; sensor; stellate cell; therapeutic target; treatment strategy

ABSTRACT A pivotal stage of the ALD progression is the development of hepatic inflammation, which substantially increases the risk for fibrosis, cirrhosis and cancer. Despite the recent surge in the use of immunomodulatory biologics for other inflammatory diseases, corticosteroids remain the only therapeutic for hepatic inflammation, underscoring a major unmet clinical need. While evidence indicates that a combination of ethanol-induced hepatocyte cell death and elevated circulating endotoxin drives hepatic inflammation in ALD, a major question arising is how the chronic low grade inflammation is initiated and amplified in the progression of ALD. We reported that low-dose endotoxin induces the expression of Mincle, a member of the C-type lectin receptor family that acts as a sensor for cell death, via the IRAKM-dependent TLR4 signaling in hepatic macrophages. Mincle detects components released by dead hepatocytes and activates inflammasomes and IL-1β production, serving as a critical link between cell death and inflammation in murine models of ALD. Recently, we found serum concentrations of β- glucosylceramide (GluCer), a Mincle ligand released by dying hepatocytes, are increased by ethanol feeding in mice and highly elevated in sera from patients with AH. GluCer concentrations were positively correlated with disease severity in patients, suggesting that GluCer may be a major Mincle ligand driving hepatic inflammation and fibrosis in ALD. Intriguingly, Mincle activation leads to a non-lytic form of IL-1β secretion from hepatic macrophages and hepatic stellate cells (HSCs) via a novel GSDMD-mediated biogenesis and release of small extracellular vesicles (sEVs). The non-lytic IL-1β secretion spares hepatic macrophages from pyroptosis, allowing them to continue amplifying the inflammatory response. Importantly, our preliminary data highlight a critical pathogenic role for IL-1β containing sEVs in potentiating ethanol-induced liver injury in mice. Mechanistically, we found that IL-1β induced the expression of SAA in hepatocytes, which in turn activated caspase3-GSDME-mediated pyroptosis. Hepatocyte pyroptosis releases the danger signal HMGB1, which can further activate caspase 1 and 11-dependent GSDMD-cleavage in neighboring hepatocytes, amplifying hepatocyte injury. This escalation of injury not only impairs liver function but likely leads to further release of GluCer, amplifying macrophage inflammatory responses. Importantly, our preliminary data reveal that GluCer also activated HSCs, enhancing collagen deposition and aggravating liver fibrosis. By dissecting the GluCer- Mincle-GSDMD-IL-1β-sEV cascade, this application will evaluate strategies and identify therapeutic targets to interrupt this positive feed forward loop that amplifies the early stage hepatocyte cell death into debilitating hepatic inflammation and fibrosis.

摘要 酒精性肝脏疾病进展的一个关键阶段是肝脏炎症的发展，该炎症大幅增加 纤维化、肝硬化和癌症的风险。尽管最近使用免疫调节生物制剂用于 在其他炎症性疾病中，皮质类固醇仍然是肝脏炎症的唯一治疗药物， 一个主要的未满足的临床需求。虽然有证据表明，乙醇诱导的肝细胞 死亡和升高的循环内毒素驱动ALD中的肝脏炎症，出现的主要问题是 慢性低度炎症在ALD的进展中开始并扩大。我们报道过低剂量 内毒素诱导Mincle的表达，Mincle是C型凝集素受体家族的成员，作为传感器 通过肝巨噬细胞中的IRAKM依赖性TLR 4信号传导导致细胞死亡。Mincle检测组件 由死亡的肝细胞释放并激活炎性小体和IL-1β产生，作为关键环节 细胞死亡和炎症之间的关系。最近，我们发现血清中β- 葡萄糖神经酰胺（GluCer），一种由垂死肝细胞释放的Mincle配体，在肝细胞中通过乙醇喂养增加， 在小鼠和AH患者血清中高度升高。GluCer浓度正相关， 提示GluCer可能是驱动肝脏炎症的主要Mincle配体 和纤维化。有趣的是，Mincle激活导致肝脏分泌IL-1β的非溶解形式， 巨噬细胞和肝星状细胞（HSC）通过一种新的GSDMD介导的生物合成和释放小 细胞外囊泡（sEV）。非溶解性IL-1β分泌使肝巨噬细胞免于焦亡， 让它们继续放大炎症反应。重要的是，我们的初步数据突出了一个 含有IL-1β的sEV在增强小鼠乙醇诱导的肝损伤中的关键致病作用。 从机制上讲，我们发现IL-1β诱导肝细胞SAA的表达，而SAA反过来激活了 半胱天冬酶3-GSDME介导的焦亡。肝细胞凋亡释放危险信号HMGB 1， 进一步激活邻近肝细胞中的半胱天冬酶1和11依赖性GSDMD裂解， 肝细胞损伤这种损伤的升级不仅损害肝功能，而且可能导致进一步释放 GluCer，放大巨噬细胞炎症反应。重要的是，我们的初步数据显示，GluCer 还激活HSC，增加胶原沉积，加重肝纤维化。通过解剖谷氨酸酶 Mincle-GSDMD-IL-1β-sEV级联反应，该申请将评估策略并确定治疗靶点， 中断这种正向前馈循环，该循环将早期肝细胞死亡放大为使 肝脏炎症和纤维化。