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

项目总结/摘要 人类密集地寄居着共生细菌-统称为微生物组- 调节生理学，例如通过有效的小分子。广泛的努力既确定了关键的 微生物组在健康人体生物学中的作用以及微生物组的相关组成及其相关的 从自身免疫性疾病到神经系统疾病。底层 然而，宿主-微生物组相互作用的分子机制在很大程度上是不确定的，阻碍了 开发微生物组相关疾病的治疗干预措施。 高通量功能基因组学研究方法的最新进展 人类和细菌基因，如基于CRISPR的基因筛选，现在原则上可以系统地 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的表型;一旦实施，它们代表了 这是一个强有力的工具，可以识别参与产生这些表型的基因。 该建议描述了功能基因组学方法的发展， 树突状细胞，微生物组和人类免疫系统之间相互作用的模型系统，以及 这些方法在鉴定两类受体及其生理作用中的应用 细菌糖脂、荚膜多糖和脂多糖。这两类都是非常丰富的， 微生物组和个别例子表明这些分子在调节 免疫功能例如，已知单独的荚膜多糖可诱导分化的细胞。 调节性T细胞和脂多糖是先天性免疫细胞的配体，并引起不同的反应 从炎症到免疫抑制。在这个建议中，新菌株的开发 具有糖脂结构受控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，并识别宿主 受体和信号通路介导这些作用。这种对潜在机制的剖析 宿主-微生物组界面的糖脂信号传导将提高对微生物组在 调节免疫系统的功能和成熟。 本提案中所述的方法同样适用于研究其他组织的作用。 微生物组来源的分子、与微生物组疾病有关的人类受体或个体细菌 菌株总而言之，这项提案将为微生物组的生物学提供新的见解，并建立 通常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.