Microbial Chemical Sensing and Host Responses

总结。 数以万计的细菌细胞产生的数以万计的微生物代谢物 肠道(我们的微生物区系)知之甚少，目前的估计表明，我们只知道生物学上的 来自微生物区系的所有小分子中0.1%的功能。其中的一些代谢物被称为 代谢体的“暗物质”无疑会对人体生理产生深远的影响。在这里，我们将 确定人类微生物组如何通过暗物质衍生的分子与宿主“交流” 宿主G蛋白偶联受体(GPCRs)的调节，包括由 由微生物区系编码的新小分子(Aim 1a)，来自内源的GPCR信号效应 宿主化学物质(目标1b)，重组化学物质的GPCR靶向药物的肠道细菌转化 宿主-微生物区系界面的信号程序(目标2)。一个主要的焦点将是结构、功能和 与“孤儿”GPCR信号相关的新代谢物的生物合成特征 目前可以获得化学和生物信息。我们的建议利用了两项研究的结果 高通量筛查和一个目标筛查，每个筛查都侧重于微生物如何 或宿主代谢在详细的分子水平上影响宿主GPCR信号转导。在初步的高吞吐量 研究：1)我们分析了大约150种不同的人类肠道细菌，以分泌激活的代谢物 使用高通量GPCRs筛选系统的常规GPCRs(314 GPCRs)(目标1a)。我们有 这项筛查鉴定的细菌代谢物到目前为止激活了三个孤儿GPCR 从而建立了一条“gpr去孤构化”的管道。2)我们已经对人体组织进行了小分子筛选 在没有报告的配基信息的情况下激活“孤立的”GPCRs(目标1b)，为 阐明内源性孤儿gpr信号的结构和分布。3)我们已经评估了 由数十个专家组成的小组处理271种FDA批准的药物(包括62种GPCR靶向药物) 微生物区系衍生的细菌。这一初步数据包括585,000种药物的微生物区系测量。许多 药物代谢产物和细菌对药物的反应可以在代谢组学数据中观察到，指导 从肠道微生物区系中发现新的GPCR药物转化和“特殊”代谢物 生产是对GPCR药物的反应诱导的(目标2)。拟议的研究将是迄今为止的一项 前所未有的基于结构功能的微生物代谢组“暗物质”的探索以及如何 它是被主人“感觉到”的。这类研究可能会为gpcr和微生物区系靶向治疗提供新的思路。 应对多种人类疾病的战略。

Summary. The tens of thousands of microbial metabolites produced by the trillions of bacterial cells that colonize our intestines (our microbiota) are poorly understood, and current estimates suggest that we only know the biological functions of 0.1% of all small molecules derived from the microbiota. Some of the metabolites in this so called “dark matter” of the metabolome will undoubtedly have profound impacts on human physiology. Here, we will establish how the human microbiome “communicates” with the host via dark-matter-derived molecular modulation of host G protein-coupled receptors (GPCRs), including GPCR signaling effects mediated by novel small molecules encoded by the microbiota (Aim 1a), GPCR signaling effects derived from endogenous host chemicals (Aim 1b), and gut bacterial transformations of GPCR-targeted medical drugs that rewire chemical signaling programs at the host-microbiota interface (Aim 2). A major focus will be the structural, functional, and biosynthetic characterization of novel metabolites associated with “orphan” GPCR signaling where only limited chemical and biological information is currently available. Our proposal takes advantage of the results from two high-throughput screens and one targeted screen, which each focused on different aspects of how microbial or host metabolism impacts host GPCR signaling at a detailed molecular level. In preliminary high-throughput studies: 1) We have analyzed ~150 diverse human gut bacteria for secretion of metabolites that activate conventional GPCRs (314 GPCRs) using a high-throughput GPCR screening system (Aim 1a). We have characterized bacterial metabolites identified by this screen that activate three orphan GPCRs to date and have thus established a pipeline for “GPCR deorphanization.” 2) We have screened human tissues for small molecules that activate “orphan” GPCRs with no reported ligand information available (Aim 1b), providing a basis to elucidate the structure and distribution of endogenous orphan GPCR signals. 3) We have evaluated the processing of 271 FDA-approved drugs (including 62 GPCR-targeted drugs) by a panel of dozens of gut microbiota-derived bacteria. This preliminary data includes 585,000 drug-by-microbiota measurements. Many drug metabolism products and bacterial responses to drugs can be observed in the metabolomics data, guiding the discovery of novel GPCR drug transformations and “specialized” metabolites from the gut microbiota whose production is induced in response to GPCR drugs (Aim 2). The proposed studies will represent a heretofore unprecedented structure-function-based exploration of the “dark matter” of the microbiota metabolome and how it is “sensed” by the host. Such studies may illuminate novel GPCR- and microbiota-targeted therapeutic strategies for a diversity of human diseases.