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

项目总结： 多发性硬化症(MS)是一种慢性自身免疫性中枢神经系统(CNS)疾病，是导致多发性硬化症的主要原因 年轻人中的非创伤性神经功能障碍。多发性硬化症的病因很复杂，不能归因于 任何风险超过70%的单基因都可归因于环境因素。最近的研究发现了一种不平衡 在多发性硬化症患者的人体肠道微生物群中作为一种这样的环境风险，包括耗尽 乳杆菌属。动物模型支持肠道微生物群在多发性硬化症中的因果作用，尽管 目前仍不清楚。利用多发性硬化症的小鼠模型，我们已经鉴定出抗病和易感 微生物群，乳酸菌种类丰度有显著差异，其 循环代谢副产物，已知可调节免疫系统。此外，我们已经确定了一种 共生种，reuri乳杆菌(L.reuri)，足以加重MS样症状 小鼠的全基因组测序表明有必要的酶机制来解释 观察到循环代谢物的差异。这项建议的重点是1)确定蜂窝 罗氏乳杆菌对EAE的作用机制，包括对外周免疫的影响 细胞和CNS驻留的神经胶质细胞和2)确定L.reuri衍生的色氨酸代谢产物对 神经炎。 在直接支持拟议研究的情况下，培训计划将发展知识、专门知识、科学 关注宿主相互作用的多发性硬化症小鼠模型的沟通技巧和技术能力 肠道微生物组，包括直接微生物组操作，2)免疫学，重点是 神经免疫学、流式细胞术和体外和体内的功能分析，3)微生物学，重点是 共生肠道细菌及其培养、分离、基因组和代谢特征以及操作，4) 神经病理学，重点是研究中枢神经系统病理以表征炎症的技术 中枢神经系统自身免疫性疾病脱髓鞘病变与血脑屏障完整性分析 代谢组学，重点研究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，具有大学氛围， 强调积极的指导，因此唯一适合支持这一建议的是 自身免疫，中枢神经病理和共生微生物区系。这一点得到了与 生物医学和健康科学系(BHSC)、微生物学和分子系的任命 遗传学(MMG)和神经科学，连接到核心设施和Larner的枢纽 医学院提供了充分的机会来分享资源和促进面对面的交流。

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.