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

项目摘要 炎症和传染病是全世界的主要死因之一。协调和 调节免疫防御对于对抗感染和预防异常炎症至关重要 应答这在胃肠道内尤其重要，因为潜在的病原体必须在胃肠道内传播。 与浮游微生物的区别我们肠道微生物群落的有害改变（生态失调）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， 一个关键的屏障和接口与我们的管腔环境。肠细胞具有先天免疫的所有功能， 受体和防御机制，使它们能够直接响应和调节肠道细菌。所以他们 被认为在建立和维持我们发展的有益的共生关系方面起着关键作用 肠道菌群的影响值得注意的是，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肠道和病原体， 这种肠道细胞反应促进了肠道中的细胞选择。本提案的长期目标 是为了确定肠道细胞如何直接参与肠道的选择和维持， 细菌拟议的研究方法，这一目标，利用易处理性和简单性的 模式生物C. elegans提供精细尺度的空间分辨率， 宿主与微生物之间的相互作用C.线虫是肠道发育和先天免疫的模型， 在自然界中也有多种肠道微生物，使C. elegans是研究微生物的一个很好的系统， 诱导先天免疫反应。目标1将确定细菌和社区特异性免疫 通过评估肠细胞对以下物质的转录反应， 使用单细胞RNA测序（scRNA-seq）的肠道和致病性肠道细菌。这将揭示独特的 基于细菌暴露的整个肠道的肠细胞之间的先天免疫特征。初步 来自我们胚胎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- 型凝集素（CLEC），其在哺乳动物中的细菌识别中具有明确的作用。目标2将决定 肠细胞如何通过测试先天免疫受体的作用来调节肠道中的细菌定植， 特别是CLEC，在选择和维持肠道细菌方面。使用分子的组合 生物学和显微镜技术，目标2将阐明CLECs的队列需要识别和响应 到肠道细菌。这项研究的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结合C.具有创新机制的优雅 分析我们将移动C。线虫研究社区向前发展，重要的是，揭示保守的途径 使得能够创建可推广的概念，而不仅仅限于C。优雅

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.