Microbiome and Intestinal Innate Immune Response in Alcoholic Liver Disease

项目摘要 酗酒和与酒精有关的疾病是工业化国家的一个主要医疗负担。慢性 酒精中毒与肠道微生物群的变化，肠道通透性的增加， 细菌产物的全身水平升高。粪肠球菌（Enterococcus faecalis，E.粪便）是 足以引起轻度脂肪变性肝病并加重小鼠中乙醇诱导的肝病。我们 鉴定出溶细胞素，一种由大肠杆菌分泌的两个亚基外毒素。粪便，导致肝细胞死亡和肝损伤。 与对照组相比，酒精使用障碍或酒精性肝炎患者的粪便数量增加 大肠粪便溶细胞素阳性（溶细胞）E.粪便与肝病严重程度相关， 酒精性肝炎患者的死亡率慢性酒精使用如何导致肠道和肝脏 溶细胞素阳性E.粪便是未知的。我们实验室的结果表明， 肠内E.肠道糖萼的变化，特别是 减少肠上皮细胞顶膜糖蛋白的β（1，2）-岩藻糖基化。酒精- 岩藻糖基转移酶2（Fut 2）介导的抑制允许肠道定植和细菌移位 大肠粪便此外，易位E.粪便被补体吞噬并消除 Kupffer细胞上的免疫球蛋白超家族（CRIg）受体。慢性酒精性肝炎患者 具有较低的肝CRIg表达，这减少了E.粪肠球菌消除，E. coli.粪 并增加肝损伤。因此，乙醇相关的肠道定植和肝脏 消除E.粪便会促进酒精相关的肝病。我们的实验方法是使用小鼠 乙醇喂养模型，以研究Fut 2在限制E.粪肠球菌和 减少肝脏疾病（目标1）。我们还将评估吞噬蛋白CRIg对细胞凋亡的功能贡献。 E.粪便消除和肝脏疾病（目的2）。将测试新的战略，以防止和改善 临床前模型中乙醇诱导的肝病。我们相信，这些研究将提供新的见解， 微生物群对酒精相关肝病的贡献。

Project Summary Alcohol abuse and alcohol-related diseases are a major medical burden in industrialized countries. Chronic alcoholism is associated with changes in the intestinal microbiota, increases in intestinal permeability, and elevated systemic levels of bacterial products. We demonstrated that Enterococcus faecalis (E. faecalis) is sufficient to cause mild steatotic liver disease and to exacerbate ethanol-induced liver disease in mice. We identified cytolysin, a two-subunit exotoxin secreted by E. faecalis, to cause hepatocyte death and liver injury. Compared with controls, patients with alcohol use disorder or alcoholic hepatitis have increased fecal numbers of E. faecalis. The presence of cytolysin-positive (cytolytic) E. faecalis correlated with liver disease severity and mortality in patients with alcoholic hepatitis. How chronic alcohol use results in increased intestinal and hepatic numbers of cytolysin-positive E. faecalis is not known. Results from our laboratory suggest that increased intestinal numbers of E. faecalis are facilitated by changes in the intestinal glycocalyx and in particular by reduced (1,2)-fucosylation of glycoproteins on the apical membrane of intestinal epithelial cells. Alcohol- mediated suppression of Fucosyltransferase 2 (Fut2) allows intestinal colonization and bacterial translocation of E. faecalis. Furthermore, translocated E. faecalis is phagocytosed and eliminated by the complement receptor of the immunoglobulin superfamily (CRIg) on Kupffer cells. Patients with chronic alcoholic hepatitis have lower hepatic CRIg expression, which reduces E. faecalis elimination, prolongs exposure to E. faecalis and increases liver damage. Thus, ethanol associated changes in intestinal colonization and hepatic elimination of E. faecalis promotes alcohol-related liver disease. Our experimental approach is to use mouse models of ethanol feeding to investigate the role of Fut2 in limiting intestinal colonization of E. faecalis and reducing liver disease (Aim 1). We will also assess the functional contribution of the phagocytic protein CRIg to E. faecalis elimination and to liver disease (Aim 2). New strategies will be tested to prevent and ameliorate ethanol-induced liver disease in preclinical models. We believe these studies will provide novel insights into the contribution of the microbiota to alcohol-related liver disease.