Mechanisms of gamma delta intraepithelial lymphocyte-mediated host defense

γδ上皮内淋巴细胞介导的宿主防御机制

• 批准号: 9976324
• 负责人: Madeleine Hu
• 金额: $ 4.21万
• 依托单位: RBHS-NEW JERSEY MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9976324
• 关键词: Academic Medical Centers; Acute; Advisory Committees; Anti-Bacterial Agents; Antibacterial Response; Apoptotic; Autoimmunity; Automobile Driving; Bacteria; Bacterial Translocation; Basic Science; Behavior; Cells; Clinical; Data; Development; Enteral; Enterocytes; Epithelial; Epithelial Cells; Epithelium; Event; Exhibits; Extracellular Space; Failure; Focal Infection; Foundations; Future; Goals; Health; Home environment; Host Defense; Immune; Immune system; In Vitro; Infection; Inflammation; Inflammatory Bowel Diseases; Inflammatory Response; Institution; Intestinal Mucosa; Intestines; Knockout Mice; Knowledge; Laboratories; Lateral; Lead; Lipopolysaccharides; Lymphocyte; Lymphocyte Function; Maintenance; Mediating; Mentors; Microbe; Migration Assay; Mission; Molecular; Mucous Membrane; Mus; National Institute of Diabetes and Digestive and Kidney Diseases; Nuclear Translocation; Pathologic; Pattern; Pattern Recognition; Peritoneal; Phenotype; Physicians; Predisposition; Process; Production; Public Health; Receptor Signaling; Regulation; Relapse; Reporter; Research; Research Training; Role; Salmonella; Salmonella typhimurium; Scientist; Signal Transduction; Skin; Systemic infection; T-Cell Receptor; Testing; Therapeutic; Toll-like receptors; Training; Translational Research; United States National Institutes of Health; Wild Type Mouse; Work; adaptive immune response; antimicrobial peptide; base; career; cell motility; collaborative environment; commensal bacteria; cytokine; human disease; improved; in vivo; insight; interest; intestinal epithelium; intraepithelial; intravital microscopy; microbial; migration; monolayer; novel; pathogen; pathogenic bacteria; prevent; programs; response; skills; translational medicine; γδ T cells

PROJECT SUMMARY/ABSTRACT. The intestinal epithelium is the first line of defense against the trillions of bacteria in the intestinal lumen. Failure to prevent or limit bacterial invasion can lead to infection and may trigger a harmful inflammatory response, as seen in inflammatory bowel disease. Intraepithelial lymphocytes (IEL) expressing the γδ T cell receptor rapidly respond to bacterial translocation through modulation of their migratory behavior and release of soluble host defense factors, including cytokines and antimicrobial peptides (AMP). Though γδ IELs are an essential part of host antibacterial response, many of the processes surrounding γδ IEL-mediated host defense remain unclear. The objective of this application is to elucidate the mechanisms through which γδ IELs contribute to host antibacterial defense. Preliminary data suggests that γδ IEL surveillance behavior and effector function may be partially mediated by cell-autonomous recognition of microbe-associated molecular patterns (MAMP) through Toll-like receptor/MyD88 signaling. Moreover, a newly-identified requirement for γδ IELs in lipopolysaccharide (LPS)-induced epithelial cell shedding may represent a novel form of γδ IEL- mediated host antibacterial defense, as extrusion of enterocytes infected with intracellular bacteria limits pathogen proliferation within the epithelium. These observations have led to the central hypothesis that γδ IELs contribute to host defense against bacterial invasion by activating migratory and effector responses following cell-autonomous MAMP recognition and by promoting the shedding of infected enterocytes. The aims of this application are to 1) determine the contributions of γδ IEL MyD88 signaling to host defense against acute bacterial invasion and 2) determine the mechanisms through which γδ IELs regulate cell shedding in response to acute bacterial challenge. The role of γδ IEL MyD88 in mediating MAMP-induced changes in γδ IEL migration and cytokine/AMP secretion will be assessed using inducible, γδ T-cell-specific MyD88 knockout mice and a combination of in vitro and in vivo approaches. Further, the contribution of γδ IEL MyD88 to antibacterial defense will be determined using Salmonella Typhimurium infections. Next, the mechanisms by which γδ T cells promote LPS-induced epithelial cell shedding will be interrogated by quantifying cell shedding in mice exhibiting altered γδ IEL migratory phenotypes or following γδ TCR inhibition. The requirement for γδ IELs in shedding of Salmonella-infected enterocytes will be assessed at early infection timepoints. Completion of these aims will provide novel insight into the mechanisms driving γδ IEL-mediated antibacterial defense. The results of these studies will contribute towards the long-term goal of determining the therapeutic potential of targeting γδ IEL effector functions as a means to prevent excessive inflammation by promoting rapid clearance of infection. The proposed research and training plan, along with my mentors, advisory committee, and the interdisciplinary environment at my home institution, will help me achieve my long- term career goal of becoming an effective physician-scientist involved in independent translational research.

项目摘要/摘要。 肠上皮是抵御肠腔内数万亿细菌的第一道防线。 未能预防或限制细菌入侵可能会导致感染，并可能引发有害的炎症 反应，如表达 γδ T 细胞的上皮内淋巴细胞 (IEL) 中所见。 受体通过调节细菌的迁移行为和释放对细菌易位做出快速反应 尽管 γδ IEL 是一种可溶性宿主防御因子，包括细胞因子和抗菌肽 (AMP)。 宿主抗菌反应的重要组成部分，许多围绕 γδ IEL 介导的宿主防御的过程 目前尚不清楚该应用的目的是阐明 γδ IEL 的机制。 初步数据表明 γδ IEL 监视行为和有助于宿主抗菌防御。 效应器功能可能部分由微生物相关分子的细胞自主识别介导 模式（MAMP）通过Toll样受体/MyD88信号传导此外，新确定的γδ需求。 脂多糖（LPS）诱导的上皮细胞脱落中的 IEL 可能代表 γδ IEL 的一种新形式 介导宿主抗菌防御，因为被细胞内细菌感染的肠上皮细胞的挤出受到限制 这些观察结果得出了 γδ 的中心假设。 IEL 通过激活迁移和效应反应，有助于宿主防御细菌入侵 细胞自主 MAMP 识别并促进受感染肠上皮细胞脱落。 本应用的目的是 1) 确定 γδ IEL MyD88 信号传导对宿主防御的贡献 抵抗急性细菌入侵，2) 确定 γδ IEL 调节细胞的机制 γδ IEL MyD88 在介导 MAMP 诱导中的作用。 γδ IEL 迁移和细胞因子/AMP 分泌的变化将使用诱导型、γδ T 细胞特异性进行评估 MyD88 敲除小鼠以及体外和体内方法的结合此外，γδ IEL 的贡献。 接下来，将使用鼠伤寒沙门氏菌感染来确定 MyD88 的抗菌防御能力。 γδ T 细胞促进 LPS 诱导的上皮细胞脱落的机制将受到质疑 量化表现出改变的 γδ IEL 迁移表型或 γδ TCR 抑制后的小鼠的细胞脱落。 将在早期感染时评估沙门氏菌感染的肠上皮细胞脱落时对 γδ IEL 的需求 完成这些目标将为驱动 γδ IEL 介导的机制提供新的见解。 这些研究的结果将有助于确定抗菌防御的长期目标。 靶向 γδ IEL 效应子的治疗潜力可作为预防过度炎症的手段 与我的导师一起促进快速清除感染。 咨询委员会以及我所在机构的跨学科环境将帮助我实现我的长期目标 长期职业目标是成为一名参与独立转化研究的有效医师科学家。