Major Histocompatibility Complex Shapes Early Life Microbial Events to prevent Autoimmunity

项目摘要： 1型糖尿病（T1 D）是一种使人衰弱的自身免疫性疾病，影响数百万人。可惜 T1 D的发病率正在上升。T1 D中最强的遗传因素是MHC II类基因座。某些MHC单倍型 与T1 D的高风险相关，而其他人则提供主要保护。然而，机制仍然存在， 未知最近的研究表明，环境因素，如微生物组，也有助于 T1 D发病率上升。虽然遗传和环境因素都有助于发展的风险 T1 D，对MHC II遗传因子如何与微生物因子相互作用知之甚少。非肥胖型糖尿病（NOD） 鼠模型重现了人类T1 D的许多特征，包括与T1 D相关的显性保护， MHC II类基因座NOD小鼠自发发展T1 D，但转基因可预防自身免疫 MHCII E等位基因的表达（Eα16/NOD小鼠）。最近发表的研究和新的初步数据 我们的实验室表明，微生物群对这种保护至关重要。本提案的目的是确定 免疫调节细菌和免疫系统途径，可用于开发预防性T1 D 遗传风险患者的治疗 为了严格研究早期微生物，我们开发了一种由9种可培养细菌组成的新型财团。 （我们称之为PedsCom）代表了断奶前糖尿病保护的Eα16/NOD中90%以上的细菌 小鼠为了研究特定细菌的免疫调节机制，我们正在应用gnotobiotic技术 使用PedsCom财团和使用Eα16/NOD小鼠的疾病遗传模型。实验 在这项建议中概述的将阐明MHC II分子与肠道相互作用的机制 预防T1 D的微生物在目标1中，我将研究MHC II E表达是否影响早期生活事件的形成， 微生物定植，通过比较定植动力学和体液反应， NOD和Eα16/NOD小鼠被PedsCom联合体定殖。在目标2中，我将确定PedsCom是否 早期微生物的联合体足以预防T1 D，外周调节性T细胞是否能预防T1 D， 通过研究PedsCom、无特定病原体（SPF）和无菌定植小鼠，在Eα16/NOD小鼠中观察T1 D。 在此期间，这些研究将扩大我的技术技能，提高我的能力， 实验设计和分析，并提高我的沟通能力，发现科学界。 我将在宾夕法尼亚大学完成这项奖学金，该大学提供项目，课程和结构 这将有助于我的职业发展。此外，我将利用 免疫学研究生组和医学科学家培训计划，以提高我的能力， 教育家和临床医生。利用我现有的资源，我将探索基本的和临床相关的 在这个建议的问题，以获得必要的技能，成为一个成功的医生科学家。

Project Summary: Type 1 diabetes (T1D) is a debilitating autoimmune disease that affects millions. Unfortunately, the incidence of T1D is rising. The strongest genetic factor in T1D is the MHC class II locus. Some MHC haplotypes are associated with higher risk to T1D, while others provide dominant protection. Yet, the mechanism remains unknown. Recent studies suggest that environmental factors, such as the microbiome, also contribute to the increasing incidence of T1D. While both genetic and environmental factors contribute to the risk of developing T1D, little is known of how MHC II genetic factors interact with microbial factors. The non-obese diabetic (NOD) murine model recapitulates many features of T1D in humans including the dominant protection associated with the MHC class II locus. NOD mice spontaneously develop T1D, but autoimmunity can be prevented by transgenic expression of the MHCII E allele (Eα16/NOD mice). Recent published studies and new preliminary data from our laboratory suggests that microbiota are critical for this protection. The goal of this proposal is to identify immunomodulatory bacteria and immune system pathways that can be used to develop preventative T1D therapies for genetically at-risk patients To rigorously study the early-life microbiota, we developed a novel consortium of 9 culturable bacteria (which we call PedsCom) that represent over 90% of the bacteria in pre-weaning diabetes-protected Eα16/NOD mice. To investigate immunomodulatory mechanisms of specific bacteria, we are applying gnotobiotic techniques using the PedsCom consortium and genetic models of disease utilizing Eα16/NOD mice. The experiments outlined in this proposal will elucidate the mechanisms by which MHC II molecules interact with intestinal microbes to prevent T1D. In Aim 1, I will investigate if MHC II E expression impacts early-life events to shape microbial colonization by comparing colonization dynamics and humoral responses to commensal bacteria in the NOD and Eα16/NOD mice colonized by the PedsCom consortia. In Aim 2, I will determine if the PedsCom consortia of early-life microbes are sufficient to prevent T1D and whether peripheral regulatory T cells prevent T1D in Eα16/NOD mice by studying PedsCom, specific pathogen free (SPF), and germ-free colonized mice. During this fellowship, these investigations will expand my technical skills, improve my aptitude for experimental design and analysis, and enhance my ability to communicate findings to the scientific community. I will complete this fellowship at the University of Pennsylvania, which offers programs, courses, and structured mentorships that will aid my career development. In addition, I will take advantage of opportunities offered by the Immunology Graduate Group and the Medical Scientist Training Program to enhance my abilities as an educator and a clinician. With the resources available to me, I will explore the fundamental and clinically relevant questions in this proposal to gain the skills necessary to become a successful physician scientist.