Epithelium, dendritic cells, and Clostridium difficile associated colitis

上皮、树突状细胞和艰难梭菌相关结肠炎

• 批准号: 7887611
• 负责人: Hanping Feng
• 金额: $ 41.53万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7887611
• 关键词: Accounting; Acute; Antibiotics; Antigen-Presenting Cells; Apoptosis; Apoptotic; Bacteria; Blood; CDC42 gene; Cell Communication; Cell Death; Cell Line; Cells; Clostridium difficile; Colitis; Cytoskeleton; Dendritic Cells; Development; Diarrhea; Disease; Enterocolitis; Environment; Epithelial; Epithelial Cells; Epithelium; Europe; Exotoxins; Exposure to; Family; Fluids and Secretions; Goals; Homeostasis; Hospitalization; Hospitals; Immune; Immune response; Immunity; In Vitro; Incidence; Infection; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Inflammatory Response; Inflammatory disease of the intestine; Intervention; Intestinal Mucosa; Intestines; Knowledge; Laboratories; Lamina Propria; Mediating; Microscope; Microscopy; Molecular; Morbidity - disease rate; Mucous Membrane; Mus; Nature; Necrosis; North America; Outcome; Process; Production; Proteins; Pseudomembranous Colitis; Role; Severities; Severity of illness; Stream; Stress; Testing; Tight Junctions; Tissues; Toxin; Work; abstracting; base; cell motility; chemokine; cytokine; design; in vivo; macrophage; migration; molecular mass; mortality; public health relevance; response; rho; rho GTP-Binding Proteins; two-photon

DESCRIPTION (provided by applicant): Clostridium difficile, an etiologic agent for pseudomembranous colitis, accounts for a quarter cases of antibiotic-associated diarrhea. With the recent emergence of hypervirulent strains, the incidence of C. difficile infection (CDI) has increased significantly in both North America and Europe, causing lengthy hospitalization, substantial morbidity and mortality. CDI is thought to be mainly mediated by exotoxins TcdA and TcdB, which glucosylate low molecular mass GTPase of the Rho family, leading to massive fluid secretion, acute inflammation, and necrosis of the colonic mucosa. Our long-term goal is to understand the mechanisms mediating intestinal inflammation in C. difficile infection and to utilize this knowledge for the design of better immune interventions in order to reduce the incidence of CDI and severity of the disease. The interaction of intestinal epithelial cells (IECs) with intestinal antigen presenting cells (APCs), such as dendritic cells (DCs) and macrophages, in the gut orchestrates mucosal immune homeostasis and inflammatory response. Our objective is to elucidate the immune response of IECs and intestinal DCs after their exposure to C. difficile toxins and to determine the nature of their interaction on initiating intestinal inflammation and tissue destruction. To achieve this objective, we will test several working hypotheses: 1) C. difficile toxin-intoxicated IECs are capable of mobilizing and activating DCs; 2) In severe cases of CDI, C. difficile toxins can cross a severely damaged intestinal barrier and further activate DCs and macrophages; and 3) proinflammatory cytokine TNF-a synergizes with the toxins to induce apoptosis of IECs, thus exacerbating tissue destruction and enterocolitis. By testing these hypotheses, we expect to gain a better understanding of not only the underlying mechanisms by which C. difficile toxins induce severe enterocolitis, but also the role of IEC-DC interaction in the onset and development of intestinal inflammatory diseases in general. We believe that such an understanding will help us to design better immune interventions against CDI and other intestinal inflammatory diseases. PUBLIC HEALTH RELEVANCE: Clostridium difficile is the most common cause of hospital-acquired antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis, the most severe intestinal inflammation. The diseases are in mainly caused by toxins secreted by the bacteria. The goal of this project is to elucidate the immune response of the intestinal epithelial cells (the first line of cells encountering the toxins) and intestinal dendritic cells (the immune cells regulating intestinal inflammatory response) after their exposure to C. difficile toxins and to determine the nature of their interaction on initiating intestinal inflammation and tissue destruction. We believe the study will help us to design better immune interventions against C. difficile infection and other intestinal inflammatory diseases.

描述（由申请人提供）：艰难梭菌，假膜性结肠炎的病原体，占抗生素相关性腹泻病例的四分之一。随着最近高毒力菌株的出现，艰难梭菌感染（CDI）的发病率在北美和欧洲都显著增加，造成长期住院，大量发病率和死亡率。CDI被认为主要由外毒素TcdA和TcdB介导，这两种外毒素葡萄糖化了Rho家族的低分子质量GTPase，导致大量液体分泌，急性炎症和结肠粘膜坏死。我们的长期目标是了解艰难梭菌感染介导肠道炎症的机制，并利用这一知识设计更好的免疫干预措施，以减少CDI的发病率和疾病的严重程度。肠上皮细胞（IECs）与肠抗原呈递细胞（apc），如树突状细胞（dc）和巨噬细胞，在肠道中相互作用，协调粘膜免疫稳态和炎症反应。我们的目的是阐明iec和肠dc暴露于艰难梭菌毒素后的免疫反应，并确定它们在启动肠道炎症和组织破坏方面相互作用的性质。为了实现这一目标，我们将测试几个工作假设：1)艰难梭菌毒素中毒的IECs能够动员和激活DCs；2)在重症CDI病例中，艰难梭菌毒素可以穿过严重受损的肠道屏障，进一步激活dc和巨噬细胞；3)促炎细胞因子TNF-a与毒素协同诱导iec细胞凋亡，从而加重组织破坏和小肠结肠炎。通过测试这些假设，我们希望更好地了解艰难梭菌毒素诱导严重小肠结肠炎的潜在机制，以及IEC-DC相互作用在肠道炎症性疾病的发生和发展中的作用。我们相信这样的理解将有助于我们设计更好的免疫干预CDI和其他肠道炎症性疾病。