Deciphering the logic of glycolipid signaling at the host-microbiome interface

项目摘要/摘要 人类密集分布着共生细菌--统称为微生物组-- 调节生理，例如通过强有力的小分子。广泛的努力已经确定了两个关键 微生物组在健康人体生物学中的作用及其相关组成 从小分子到疾病，从自身免疫性疾病到神经疾病。潜在的 然而，宿主-微生物组相互作用的分子机制在很大程度上是未知的，阻碍了 微生物组相关疾病治疗干预措施的发展。 高通量功能基因组学方法系统研究功能的最新进展 对人类和细菌基因的研究，例如基于CRISPR的基因筛查，现在原则上能够使系统 研究宿主-微生物组相互作用的分子机制。为了实现他们的潜力 微生物组生物学，这种系统的筛选方法必须在模型系统中实施和验证 概括了与宿主-微生物组相互作用相关表型；一旦实现，它们代表 强大的工具来识别与产生这些表型有关的基因。 该提案描述了用于原始人的功能基因组学方法的发展 树突状细胞，微生物群和人类免疫系统之间相互作用的模型系统，以及 这些方法在寄主受体鉴定中的应用及两类寄主的生理作用 细菌糖脂、荚膜多糖和脂多糖。这两个阶层都有大量的 微生物组和个体例子表明了这些分子在调节中的中心作用 免疫功能。例如，已知单个荚膜多糖可以诱导分化为 调节性T细胞和脂多糖是天然免疫细胞的配体，并引起不同的反应 从炎症到免疫抑制。在这项建议中，开发了新的细菌菌株 具有受控糖脂结构变异的文库与功能基因组学方法相结合 对糖脂对免疫细胞的影响进行结构-功能分析，并确定宿主 介导这些效应的受体和信号通路。这一对潜在机制的剖析 宿主-微生物组界面上的糖脂信号将提高对微生物组在体内的作用的理解 调节免疫系统的功能和成熟。 本提案中描述的方法将同样适用于研究其他 微生物组衍生的分子，与微生物组疾病有关的人类受体，或单个细菌 菌株。总之，这项提议将为微生物组的生物学提供新的见解，并建立 普遍适用的方法来破译宿主-微生物组相互作用的机制。

Project Summary/Abstract Humans are densely colonized with symbiotic bacteria – collectively referred to as the microbiome – that modulate physiology, for example through potent small molecules. Extensive efforts have both identified crucial roles of the microbiome in healthy human biology and linked composition of the microbiome and its associated small molecules to diseases ranging from autoimmune diseases to neurological disorders. The underlying molecular mechanisms of host-microbiome interactions, however, are largely undefined, impeding the development of therapeutic interventions for microbiome-associated diseases. Recent advances in high-throughput functional genomics methods to systematically probe the functions of human and bacterial genes, such as CRISPR-based genetic screens, now in principle enable systematic studies into the molecular mechanisms of host-microbiome interactions. To achieve their potential for microbiome biology, such systematic screening methods must be implemented and validated in model systems that recapitulate phenotypes relevant to host-microbiome interactions; once implemented, they represent powerful tools to identify genes involved in producing these phenotypes. This proposal describes the development of functional genomics approaches for primary human dendritic cells, a model system for interactions between the microbiome and the human immune system, and the application of these approaches to the identification of host receptors and physiological roles of two classes of bacterial glycolipids, capsular polysaccharides and lipopolysaccharides. Both classes are highly abundant in the microbiome and individual examples have suggested central roles for these molecules in modulating immune function. For example, individual capsular polysaccharides are known to induce differentiation of regulatory T-cells, and lipopolysaccharides are ligands for innate immune cells and elicit varying responses ranging from inflammation to immunosuppression. In this proposal, the development of new bacterial strain libraries with controlled variations in glycolipid structure is combined with functional genomics approaches to conduct structure-function analyses of the effects of glycolipids on immune cells and to identify the host receptors and signaling pathways that mediate these effects. This dissection of the mechanisms underlying glycolipid signaling at the host-microbiome interface will improve understanding of the role of the microbiome in modulating function and maturation of the immune system. The approaches described in this proposal will be similarly applicable to study the roles of other microbiome-derived molecules, human receptors implicated in microbiome diseases, or individual bacterial strains. Altogether, this proposal will both provide new insight into the biology of the microbiome and establish generally applicable approaches to decipher mechanisms of host-microbiome interactions.