Elucidating the role of an immunomodulator from a gut microbe in inflammatory bowel disease

项目总结/摘要 炎症性肠病（IBD）是一种影响消化道的自身免疫性疾病。强烈 与肠道微生物群落成员的不平衡有关。目前尚不清楚是否缺席或 特定微生物的存在有助于IBD的进展。肠道微生物的单一培养 与健康或IBD相关的人进行了筛选，以确定他们产生被免疫缺陷病毒识别的分子的能力。 免疫系统促进炎症（通过诱导TNFα）或抑制炎症（通过诱导IL 10）。 从该筛选中，发现活泼瘤胃球菌产生有效的抗炎分子。这项工作 将识别和表征这种抗炎分子，确定它是如何产生的，它是如何被识别的， 免疫系统，以及它是否存在于临床样品中。 首先，来自R. gnavus将从规模扩大的培养物中纯化， 分馏一旦纯净，将使用NMR，MS和X射线的组合来确定结构 衍射法为了确定抗炎分子和潜在的类似物在其他组织中的分布， 肠道微生物的生物合成基因将通过R. gavus或异源 目的基因的表达。或者，R.将筛选gnavus（或密切相关的种属） 对于那些不产生抗炎分子的人，他们的基因组将被比较， 与抗炎活性相关的基因。 当Myd 88被敲除时，该分子的抗炎活性被消除;因此， 通过TLR被免疫系统识别。每个TLR将被敲除，以确定抗- 炎症分子被免疫系统识别。免疫系统的反应也会 其特征在于RNA-seq.抗炎分子的临床相关性将通过以下方式确定： 在先前从患者粪便样品收集的代谢组学数据中搜索其存在。可选择地， 生物合成基因的存在和表达将通过挖掘先前收集的 来自这些相同患者样品的宏基因组和转录组数据。最后，将建立小鼠IBD模型。 用于确定R. gnavus及其纯化的免疫调节剂对疾病的发生、严重程度和 进展这项工作将扩大我们对肠道微生物组成员如何调节肠道微生物的认识。 免疫系统及其与IBD的相关性，并且还可以确定治疗干预的潜在途径。

Project Summary/Abstract Inflammatory bowel disease (IBD) is an autoimmune disease that affects the digestive tract. It is strongly correlated with imbalances in members of the gut microbial community. It is not known if the absence or presence of specific microbes contributes to the progression of IBD. Monocultures of gut microbes strongly associated with health or IBD were screened for their ability to produce molecules that are recognized by the immune system to promote inflammation (by inducing TNFα) or to suppress inflammation (by inducing IL10). From this screen, Ruminococcus gnavus was found to produce a potent anti-inflammatory molecule. This work will identify and characterize this anti-inflammatory molecule, determine how it is made, how it is recognized by the immune system, and whether it is present in clinical samples. First, the anti-inflammatory molecule from R. gnavus will be purified from scale-up cultures with activity-guided fractionation. Once pure, the structure will be determined using a combination of NMR, MS and X-ray diffraction. To determine the distribution of the anti-inflammatory molecule and potential analogs among other gut microbes the biosynthetic genes will be determined through gene deletion in R. gnavus, or heterologous expression of genes of interest. Alternatively, strains of R. gnavus (or closely related species) will be screened for those that do not produce the anti-inflammatory molecule, and their genomes will be compared to identify genes associated with anti-inflammatory activity. The anti-inflammatory activity of the molecule is abolished when Myd88 is knocked out; therefore, it is likely recognized by the immune system through a TLR. Each TLR will be knocked out to determine how the anti- inflammatory molecule is recognized by the immune system. The response of the immune system will also be characterized by RNA-seq. The clinical relevance of the anti-inflammatory molecule will be established by searching for its presence in previously collected metabolomic data from patient stool samples. Alternatively, presence and expression of the biosynthetic genes will be determined by mining previously collected metagenomic and transcriptomic data from these same patient samples. Finally, a mouse IBD model will be used to determine the effects of R. gnavus and its purified immunomodulator on disease initiation, severity, and progression. This work will expand our knowledge of how a member of the gut microbiome modulates the immune system and its relevance for IBD, and may also identify potential avenues for therapeutic intervention.