Immune responses to commensal bacterial spores in the intestinal mucosa

对肠粘膜共生细菌孢子的免疫反应

基本信息

批准号：
10170250
负责人：
Jin Mo Park
金额：
$ 20.68万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-22 至 2022-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10170250
关键词：
16S ribosomal RNA sequencing Acute Anthrax disease Applications Grants Bacillus anthracis Bacillus anthracis spore Bacteria Bacterial RNA Bacterial Spores Bioinformatics Biological Assay Cell Wall Cells Colitis Colon Carcinoma Complementary DNA Data Disease Etiology Firmicutes Foundations Genomic DNA Health Promotion Homeostasis Human IFNAR1 gene Immune Immune response Immune system Immunity In Vitro Infection Inflammation Inflammatory Inflammatory Response Interferon Type I Interferons Interleukin-1 Intestinal Mucosa Intestines Investigation Knockout Mice Knowledge Label Link Malignant Neoplasms Mediating Messenger RNA Metagenomics Modeling Mucous Membrane Mus Pathogenicity Pathology Phylogenetic Analysis Physiology Play Production Property Proteins Protocols documentation RNA Reproduction spores Research Research Project Grants Resistance Ribosomal RNA Role Sampling Severities Signal Transduction Sorting - Cell Movement Stress Structure TLR2 gene TLR7 gene Tissues Toll-like receptors Transfer RNA Transplantation base chronic inflammatory disease commensal bacteria enteric virus infection genetic signature gut metagenome gut microbiome gut microbiota immunoregulation microbiota neutrophil novel pathogenic bacteria protective effect receptor response sensor transmission process

项目摘要

PROJECT SUMMARY/ABSTRACT Many bacterial species in the phylum Firmicutes produce spores. The spores of commensal and pathogenic bacteria play a crucial role in host entry and the initial encounter with the immune system. How bacterial spores interact with host immunity, however, remains poorly understood. In the proposed research project, we investigate spore-immune interactions and their impact on inflammation and tissue homeostasis in the intestinal mucosa. We discovered that RNA-sensing toll-like receptors (TLRs)—TLR7 and TLR13 in mice and their human counterparts—played a crucial role in detecting and triggering immune responses to the spores of Bacillus anthracis (BA), the etiologic agent of anthrax. BA spores harbored high amounts of RNA whose TLR- stimulating activity was retained after extraction and purification. This RNA was mainly located in the outermost layer of the spore, or the exosporium. TLR7/13 sensing of BA spores led to type I interferon (IFN-I) production from host cells. These findings prompted us to search commensal bacterial spores for similar structural features and functional properties. For this investigation, we devised a novel protocol that enabled spore isolation from fecal samples or intestinal luminal contents without ex vivo culture. This protocol allowed us to detect gut microbiota-derived spores with high RNA content and IFN-I-inducing capacity. These findings, in conjunction with the emerging evidence that "tonic" IFN-I signaling protects against colitis, colon cancer, and enteric viral infection, led us to formulate the central hypothesis that TLR sensing of spore-associated RNA is a pivotal mechanism by which commensal bacterial spores induce IFN-I-dependent tissue-protective responses in the intestinal mucosa. In the proposed research, we will verify the central hypothesis by pursuing the following specific aims: to identify the commensal bacterial species in the mouse and human gut whose spores possess an RNA-laden exosporium and IFN-I-inducing activity (Aim #1); and to establish the role of commensal bacterial spores and spore-sensing TLRs in inducing IFN-I production and suppressing inflammatory damage in the intestinal mucosa (Aim #2). Our study will advance our understanding of mucosal physiology and pathology by identifying commensal bacterial spores as major inducers of intestinal IFN-I production and demonstrating their role in immune regulation and tissue protection.

项目概要/摘要厚壁菌门中的许多细菌物种产生共生孢子和致病孢子。细菌在宿主进入宿主以及与免疫系统的初次接触中发挥着至关重要的作用。然而，在拟议的研究项目中，我们对孢子与宿主免疫的相互作用仍然知之甚少。研究孢子-免疫相互作用及其对炎症和组织稳态的影响我们在小鼠和肠粘膜中发现了 RNA 感应 Toll 样受体 (TLR)——TLR7 和 TLR13。他们的人类下属——在检测和触发对孢子的免疫反应方面发挥了至关重要的作用炭疽杆菌 (BA) 是炭疽病的病原体，BA 孢子含有大量 TLR- 的 RNA。提取纯化后保留了刺激活性，该RNA主要位于最外层。孢子层或 BA 孢子外壁的 TLR7/13 感应导致 I 型干扰素 (IFN-I) 的产生。这些发现促使我们在共生细菌孢子中寻找类似的结构。为了这项研究，我们设计了一种新的协议来启用孢子。该方案使我们能够在不进行离体培养的情况下从粪便样本或肠腔内容物中分离。检测肠道微生物群衍生的孢子，其具有高 RNA 含量和 IFN-I 诱导能力。与新出现的证据相结合，“强效”IFN-I 信号传导可以预防结肠炎、结肠癌和肠道病毒感染，使我们提出了一个中心假设：孢子相关 RNA 的 TLR 传感是一种共生细菌孢子诱导 IFN-I 依赖性组织保护反应的关键机制在所提出的研究中，我们将通过追求以下内容来验证中心假设。以下具体目标：确定小鼠和人类肠道中的共生细菌种类，其孢子具有充满 RNA 的外壁和 IFN-I 诱导活性（目标 #1）并确定其作用；共生细菌孢子和孢子感应 TLR 在诱导 IFN-I 产生和抑制中的作用肠粘膜炎症损伤（目标#2）。通过鉴定共生细菌孢子作为肠道 IFN-I 主要诱导剂来研究生理学和病理学生产并展示其在免疫调节和组织保护中的作用。