Caenorhabditis Elegans: a Model for Genetic Interaction between the Gut Microbiota and Intestinal Epithelial Cells

项目摘要 炎症性和传染性疾病是世界范围内的主要死亡原因。协调和 免疫防御的调节对于对抗感染和防止异常炎症是必不可少的。 回应。这在胃肠道中尤其重要，因为潜在的病原体必须 与共生微生物不同。我们肠道微生物群落的有害变化(生物失调)是 与许多疾病有关。在宿主-微生物相互作用的最前沿是肠道细胞，它们扮演着 一个关键的障碍和与我们的光亮环境的接口。肠道细胞拥有一套天然免疫系统 受体和防御机制，使它们能够直接对肠道细菌做出反应和调节。因此，他们 被认为在建立和维持我们发展的有益共生关系方面发挥着关键作用 用我们的肠道微生物群。值得注意的是，这些宿主-微生物相互作用的几个基本过程 仍然知之甚少，包括肠道细胞如何区分共生体和病原体或 肠道细胞的哪些反应促进了肠道的共生选择。这项提议的长期目标是 就是确定肠道细胞如何直接对选择和维持共生肠道做出贡献 细菌。拟议的研究通过利用 模型生物秀丽线虫提供剖析错综复杂所需的精细空间分辨率 潜在的宿主-微生物相互作用。线虫是肠道发育和先天免疫的模型 在自然界中也有各种各样的肠道微生物群，使线虫成为研究微生物的极佳系统- 诱导先天免疫反应。目标1将确定细菌和社区特异性免疫如何 肠道中的反应是通过评估肠道细胞对 利用单细胞RNA测序(scRNA-seq)检测肠道共生细菌和致病细菌。这将揭示独一无二的 肠道细胞之间基于细菌暴露的先天免疫特征。初步 来自我们的胚胎scRNA-seq数据集的证据突出了几个空间上不同的免疫基因，包括C- 类型凝集素(CLEC)，在哺乳动物的细菌识别中具有明确的作用。目标2将决定 肠道细胞如何通过测试先天免疫受体的作用来调节肠道的共生定植， 特别是CLECs，在选择和维持共生菌方面。使用分子的组合 生物学和显微技术，Aim 2将阐明需要识别和响应的CLEC队列 到共生肠道细菌。这项拟议的调查结果将阐明先天免疫是如何调节的。 在整个肠道的转录水平上，以及它如何有助于选择和维持 肠道中宿主与微生物的关系。通过将线虫的易驯养性与创新的机械装置相结合 分析我们将推动线虫研究社区向前发展，重要的是，揭示保守的途径 能够创造出可概括的概念，而不仅仅限于线虫。

Project Summary Inflammatory and infectious diseases are among the leading causes of death worldwide. Coordination and regulation of immune defenses are essential to combating infection and preventing aberrant inflammatory responses. This is especially important within the gastrointestinal tract where potential pathogens must be differentiated from commensal microbes. Deleterious alterations in our gut microbial community (dysbiosis) are associated with numerous diseases. At the forefront of host-microbe interactions are intestinal cells which act as a critical barrier and interface with our luminal environment. Intestinal cells possess a repertoire of innate immune receptors and defense mechanisms, allowing them to directly respond to and modulate gut bacteria. Thus, they are thought to play a critical role in establishing and maintaining the beneficial symbiotic relationships we develop with our gut microbiota. Remarkably, several fundamental processes underlying these host-microbe interactions remain poorly understood, including how intestinal cells differentiate between commensals and pathogens or which intestinal cell responses promote commensal selection in the gut. The long-term objective of this proposal is to determine how intestinal cells directly contribute to the selection and maintenance of commensal gut bacteria. The proposed research approaches this objective by leveraging the tractability and simplicity of the model organism C. elegans to provide the fine-scale spatial resolution needed to dissect the intricacies underlying host-microbe interactions. C. elegans is a model of intestinal development and innate immunity that also harbors a diverse gut microbiome in natura, making C. elegans an excellent system for studying microbial- induced innate immune responses. Aim 1 will determine how bacteria- and community-specific immune responses are organized in the intestine by evaluating the transcriptional response of intestinal cells to commensal and pathogenic gut bacteria using single-cell RNA-sequencing (scRNA-seq). This will reveal unique innate immune signatures among intestinal cells throughout the gut based on bacterial exposure. Preliminary evidence from our embryo scRNA-seq dataset highlight several spatially distinct immune genes including the C- type lectins (CLECs), which have a well-defined role in bacterial recognition in mammals. Aim 2 will determine how intestinal cells regulate commensal colonization in the gut by testing the role of innate immune receptors, specifically CLECs, in selecting for and maintaining commensal bacteria. Using a combination of molecular biology and microscopy techniques, aim 2 will elucidate the cohorts of CLECs required to recognize and respond to commensal gut bacteria. Results from this proposed investigation will clarify how innate immunity is regulated on a transcriptional level throughout the intestine and how it contributes to the selection and maintenance of host-microbe relationships in the gut. By combining the tractability of C. elegans with innovative mechanistic analysis we will move the C. elegans research community forward and, importantly, reveal conserved pathways enabling the creation of generalizable concepts not limited solely to C. elegans.