Defects in junctional adhesion molecule-A and Intestinal Permeability: Identification of Novel Mechanisms Driving Non-Alcoholic Steatohepatitis

连接粘附分子-A 和肠道通透性的缺陷：驱动非酒精性脂肪性肝炎的新机制的鉴定

• 批准号: 9913994
• 负责人: Mark J Czaja
• 金额: $ 47.1万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9913994
• 关键词: Adoptive Transfer; American; Antibodies; Attenuated; Automobile Driving; Binding; Cell Survival; Cell physiology; Cells; Cholesterol; Cirrhosis; Data; Defect; Development; Diet; Distal part of ileum; Epithelial Cells; Fatty acid glycerol esters; Fibrosis; Fructose; Functional disorder; Health; Hepatic; Hepatic Stellate Cell; Housing; Human; Immune; Impairment; Infiltration; Inflammation; Inflammatory; Insulin Resistance; Interferon-beta; Intestinal permeability; Intestines; Knock-out; Knockout Mice; Leaky Gut; Lesion; Link; Lipopolysaccharides; Liver; Liver Fibrosis; Liver diseases; Measures; Mediating; Metabolic syndrome; Modeling; Molecular; Movement; Mucositis; Mus; Natural Killer Cells; Pathogenesis; Patients; Permeability; Polymers; Ribosomal RNA; Risk; Role; Secondary to; Severities; Signal Transduction; Steatohepatitis; TLR4 gene; Testing; Tight Junctions; Time; United States; Wild Type Mouse; base; clinical application; clinically relevant; cytokine; dysbiosis; experimental study; fecal transplantation; functional disability; gut bacteria; gut microbiota; immune activation; in vivo; inflammatory disease of the intestine; inorganic phosphate; insight; intestinal barrier; intestinal epithelium; junctional adhesion molecule; liver inflammation; liver injury; liver transplantation; microbial; microbiome analysis; microbiota; molecular assembly/self assembly; mouse model; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel; novel therapeutics; obesogenic; pyrosequencing; saturated fat; sevelamer; tool; western diet

PROJECT ABSTRACT Non-alcoholic fatty liver disease (NAFLD) poses a major health risk to a growing sector of Americans. Non-alcoholic steatohepatitis (NASH) - a more aggressive liver lesion - along with NAFLD are the hepatic manifestations of metabolic syndrome (MetS), for which insulin resistance and inflammation are thought to be key drivers. This proposal takes advantage of mice with an intestinal permeability defect in tight junctions (TJs) of the intestinal epithelium that develops as a consequence of a targeted deletion of the junctional adhesion molecule A (JAM-A). Preliminary data, obtained from both JAM-A global knockout (JAM-A-/-) and VillinCreJAM- AFL/FL mouse colonies fed an obesogenic diet (HFCD), demonstrate robust steatohepatitis and early hepatic stellate cell ( H S C ) activation after eight weeks. These data raise critical unanswered questions regarding the molecular dysfunction associated with intestinal permeability and direct association with NASH progression. The proposed model will provide a unique opportunity to elucidate the molecular and cellular mechanisms responsible for impaired intestinal barrier function, significant lipopolysaccharide (LPS) translocation, as measured in vivo, that are conducive to development and progression of NASH. Therefore, the central hypothesis of this application is western diet-induced gut dysbiosis synergizes with impaired barrier function of VillinCreJAM-AFL/FL mice to facilitate translocation of LPS to the liver, promoting inflammation and fibrosis resulting in NASH progression. The central hypothesis will be tested by the following integrated specific aims. AIM 1: Demonstrate a direct link between gut LPS and hepatic innate immune activation that drives NASH development and progression in the setting of altered intestinal permeability. We hypothesize that hepatic TLR activation driven by gut LPS drives hepatic inflammation in HFCD-fed VillinCreJAM-AFL/FL mice. We will substantiate our hypothesis by determining whether treatment with an agent that can bind LPS, sevelamer, attenuates hepatic inflammation and fibrosis in HFCD-fed VillinCreJAM-AFL/FL mice. AIM 2: To test whether NASH development is dependent on a synergistic relationship between increased intestinal permeability in HFCD-fed VilllinCreJAM-AFL/FL mice and a HFCD-induced pro-inflammatory gut microbiota: We hypothesize that Western diet-induced gut microbial dysbiosis results in mucosal inflammation that further disrupts intestinal TJ molecular assembly and severely compromises gut barrier function. AIM 3: To verify that HFCD-fed VilllinCreJAM-AFL/FL mice have accelerated fibrosis as a consequence of impaired natural killer (NK) cell function that promotes hepatic stellate cell (HSC) survival. We hypothesize that HFCD-mediated depletion or functional impairment of NK cells promotes HSC survival in VillinCreJAM-AFL/FL mice. Given the preliminary data, proposed hypothesis and aims, this unique model of NASH will provide mechanistic insights that will have a high likelihood of clinical applicability for potential treatment for NASH.

项目摘要 非酒精性脂肪肝（NAFLD）对越来越多的美国人构成了重大的健康风险。 非酒精性脂肪性肝炎（NASH）-一种更具侵袭性的肝脏病变-沿着NAFLD是肝脏的 代谢综合征（MetS）的临床表现，胰岛素抵抗和炎症被认为是代谢综合征的主要原因。 关键驱动因素。这个提议利用了小鼠的紧密连接（TJ）的肠道通透性缺陷 肠上皮细胞的生长是由于有针对性地删除连接粘连 分子A（JAM-A）。从JAM-A全局敲除（JAM-A-/-）和VillinCreJAM-A-/-获得的初步数据， AFL/FL小鼠群喂食致肥胖饮食（HFCD），显示出强烈的脂肪性肝炎和早期肝硬化。 星状细胞（H S C）活化。这些数据提出了关键的未解之谜 关于与肠通透性相关的分子功能障碍以及与 NASH进展。提出的模型将提供一个独特的机会，阐明分子和细胞 导致肠屏障功能受损的机制，显著的脂多糖（LPS）易位， 如在体内测量的，其有助于NASH的发展和进展。因此中央 本申请的假设是，西方饮食诱导的肠道生态失调与受损的屏障功能协同作用， VillinCreJAM-AFL/FL小鼠促进LPS易位到肝脏，促进炎症和纤维化， NASH进展。中心假设将通过以下综合具体目标进行检验。目标1： 证明肠道LPS和驱动NASH的肝脏先天免疫激活之间的直接联系 在肠道通透性改变的情况下的发展和进展。我们假设肝脏 由肠道LPS驱动的TLR激活驱动HFCD喂养的VillinCreJAM-AFL/FL小鼠的肝脏炎症。我们将 通过确定是否用能结合LPS的药物，司维拉姆， 减轻HFCD喂养的VillinCreJAM-AFL/FL小鼠的肝脏炎症和纤维化。目标2：测试是否 NASH的发展取决于肠道渗透性增加与 在喂食HFCD的VilllinCreJAM-AFL/FL小鼠和HFCD诱导的促炎肠道微生物群中：我们 假设西方饮食诱导肠道微生物生态失调导致粘膜炎症， 破坏肠TJ分子组装并严重损害肠屏障功能。目标3：验证 HFCD喂养的VilllinCreJAM-AFL/FL小鼠由于自然杀伤细胞受损而加速了纤维化 (NK)促进肝星状细胞（HSC）存活的细胞功能。我们假设HFCD介导的 NK细胞的耗竭或功能损伤促进VillinCreJAM-AFL/FL小鼠中HSC的存活。鉴于 初步数据，提出的假设和目标，这个独特的NASH模型将提供机制的见解 其将具有用于NASH的潜在治疗的临床适用性的高可能性。