Immune regulation of the transcriptional and spatial profile of Clostridioides difficile

项目摘要 艰难梭菌是一种机会性病原体，可在下列情况下定植于患者的胃肠道 抗生素对肠道微生物群的干扰。宿主对感染的免疫反应的质量是一个 决定疾病结果的重要因素。免疫缺陷使宿主极易患上 感染，而不受控制的宿主炎症可导致疾病(28)。有趣的是，许多临床和 动物研究发现，宿主的免疫反应限制了艰难梭菌介导的组织损伤，但不会 直接驱使病原体清除(4-12)。然而，宿主免疫因素塑造艰难梭菌的可能性 超出病原体总负担的生物学在很大程度上仍然是未知的。以前的研究已经证明， 肠道内其他致病肠道细菌的生物地理学和转录活性 由粘膜免疫系统塑造(13-16)。免疫压力是否影响艰难梭菌的空间分布 而且转录图谱还没有被研究过。这一建议利用了明显的免疫缺陷小鼠 先前报告的艰难梭菌感染表现出从轻微到严重的疾病谱，尽管 难以区分的艰难梭菌负担或毒素产生。这项提案的目标将首先、可视化和 定量艰难梭菌在粘液层和中央管腔中的繁殖体和孢子负荷 肠道在不同的免疫条件下。第二，在补充性研究中，体内转录 艰难梭菌的图谱将在具有明显免疫缺陷的小鼠身上进行评估。转录的 促进产孢子、毒力因子、营养吸收、抗菌剂解毒和 将检查代谢活动，以了解艰难梭菌如何响应免疫压力以促进 持久力和传播力。这些目标将揭示新的免疫-C。艰难的相互作用决定了 疾病严重性，并提供如何调节免疫反应以支持的模板 艰难梭菌相关性疾病的常规抗生素治疗。 1

Project Summary Clostridiodies difficile is an opportunistic pathogen that can colonize a patient’s gastrointestinal tract following antibiotic perturbation of the intestinal microbiome. The quality of the host immune response to infection is an important factor in determining disease outcome. Immunodeficiencies leave the host acutely susceptible to infection, while unregulated host inflammation can drive disease (28). Interestingly, numerous clinical and animal studies have found the host immune response limits C. difficile-mediated tissue damage but does not directly drive pathogen clearance (4-12). However, the potential for host immune factors to shape C. difficile biology beyond total pathogen burden remains largely undefined. Previous studies have demonstrated that the biogeography and transcriptional activity of other pathogenic intestinal bacteria within the intestinal tract can be shaped by the mucosal immune system (13-16). Whether immunologic pressures shape C. difficile spatial and transcriptional profile has not been explored. This proposal utilizes distinct immunodeficient mice previously reported to exhibit a spectrum from mild to severe disease upon C. difficile infection despite indistinguishable C. difficile burden or toxin production. The aims of this proposal will first, visualize and quantify the C. difficile vegetative and spore burden in the mucus layer compared to the central lumen of the intestine under distinct immunologic conditions. Second, in complementary studies, the in vivo transcriptional profile of C. difficile will be assessed in mice harboring distinct immunologic deficiencies. Transcriptional pathways that promote sporulation, virulence factors, nutrient uptake, antimicrobial detoxification, and metabolic activity will be examined to understand how C. difficile responds to immune pressure to promote persistence and transmission. These aims will reveal novel immune-C. difficile interactions that determine disease severity and provide a template for how the immune response can be modulated to support conventional antibiotic treatment in treating C. difficile associated disease. 1