Mechanisms Underlying Regulation of Susceptibility to CNS Autoimmunity by Commensal Lactobacillus Species

项目概要： 多发性硬化（MS）是一种慢性自身免疫性中枢神经系统（CNS）疾病， 年轻人非创伤性神经障碍。MS的原因很复杂，不能归因于 任何一个单一的基因，超过70%的风险归因于环境因素。最近的研究发现， 在MS患者体内的人类肠道微生物组中，作为一种环境风险，包括 乳杆菌属动物模型支持肠道微生物组在MS中的因果作用，尽管其机制 仍不清楚利用MS的小鼠模型，我们已经鉴定了疾病抗性和易感性， 微生物组，乳酸杆菌物种丰度存在明显差异， 已知调节免疫系统的循环代谢副产物。此外，我们还发现了一种 乳酸菌属（Lactobacillus reuteri（L.）reuteri），这足以加重MS样症状， 小鼠全基因组测序表明必要的酶机制，以解释 观察到循环代谢物的差异。该建议的重点是1）确定蜂窝 探讨了L. reuteri对EAE的影响包括对浸润性外周免疫 细胞和CNS驻留神经胶质细胞的影响和2）确定L.罗伊氏衍生的色氨酸代谢物 神经炎症 为了直接支持拟议的研究，培训计划将发展知识、专门知识、科学知识和技能， 1）多发性硬化症小鼠模型中的沟通技巧和技术能力，重点是宿主相互作用 肠道微生物组，包括定向微生物组操作，2）免疫学，重点是 神经免疫学，流式细胞术，体外和体内功能测定，3）微生物学，重点是 肠道细菌，它们的培养、分离、基因组和代谢表征以及操作，4） 神经病理学，重点是研究CNS病理学的技术，以表征炎症 CNS自身免疫性疾病中的脱髓鞘病变和血脑屏障完整性分析，以及5） 代谢组学，重点是细菌代谢物及其对宿主生理的影响。 佛蒙特大学（UVM）的培训环境是多学科的，具有学院氛围， 强调积极的指导，因此非常适合支持这一提议， 自身免疫、CNS神经病理学和肠道微生物群。这一点得到了以下共同导师的证实： 生物医学和健康科学（BHSC），微生物学和分子生物学系的任命 遗传学（MMG）和神经科学，连接到核心设施和Larner中心 医学院提供充分的机会，分享资源，促进面对面的沟通。

Project Summary: Multiple sclerosis (MS) is a chronic autoimmune central nervous system (CNS) disease and the leading cause of non-traumatic neurological disability in young adults. The cause of MS is complex and cannot be ascribed to any single gene with over 70% risk attributed to environmental factors. Recent studies identified an imbalance in the human gut microbiome within MS patients as one such environmental risk, including depletion of the Lactobacillus genus. Animal models support a causal role for the gut microbiome in MS, though the mechanism remains unclear. Utilizing a mouse model of MS, we have identified disease resistant and susceptible microbiomes, with stark differences in Lactobacillus species abundance and notable differences in their circulating metabolic by-products known to modulate the immune system. Further, we have identified a single commensal species, Lactobacillus reuteri (L. reuteri), which is sufficient to accentuate MS-like symptoms in the mouse with whole genome sequencing indicating the necessary enzymatic machinery to account for the observed differences in circulating metabolites. The focus of this proposal is to 1) determine the cellular mechanisms underlying the effects of L. reuteri on EAE including both impact on infiltrating peripheral immune cells and CNS resident glial cells and 2) determine the impact of L. reuteri-derived tryptophan metabolites on neuroinflammation. In direct support of the proposed studies, the training plan will develop the knowledge, expertise, scientific communication skills and technical abilities in 1) mouse models of multiple sclerosis focused on host interactions with the gut microbiome including directed microbiome manipulation, 2) immunology, with a focus on neuroimmunology, flow cytometry, and functional assays in vitro and in vivo, 3) microbiology, with a focus on commensal gut bacteria, their culture, isolation, genomic and metabolic characterization, and manipulation, 4) neuropathology, with a focus on techniques to investigate CNS pathology to characterize inflammatory demyelinating lesions in CNS autoimmune disease and blood brain barrier integrity analysis and 5) metabolomics with a focus on bacterial metabolites and their effects on host physiology. The training environment at the University of Vermont (UVM) is multidisciplinary with a collegial atmosphere that stresses active mentorship and as such is uniquely appropriate to support this proposal which bridges autoimmunity, CNS neuropathology and commensal microbiota. This is evidenced by co-mentors with appointments in the departments of Biomedical and Health Sciences (BHSC), Microbiology and Molecular Genetics (MMG), and Neurological Sciences which are connected to a hub of core facilities and the Larner College of Medicine offering ample opportunity to share resources and promote in-person communication.