Innate Immune Defense against Clostridium Difficile Infection

针对艰难梭菌感染的先天免疫防御

• 批准号: 8495909
• 负责人: Eric G. Pamer
• 金额: $ 34.86万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8495909
• 关键词: Aerobic; Aftercare; Agonist; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacteria; Bacterial Infections; Body Weight decreased; Bone Marrow; Cells; Cessation of life; Clindamycin; Clostridium difficile; Colitis; Complication; Cytokine Receptors; Defense Mechanisms; Dendritic Cells; Development; Diarrhea; Disease; Dose; Enteral; Environment; Epithelial Cells; Flagellin; Gastrointestinal tract structure; Germination; Goals; Gram-Positive Bacteria; Growth; Healthcare; Hospitals; Hydrocarbons; Immune; Immune system; Immunocompromised Host; Implant; Incidence; Infection; Inflammatory; Ingestion; Intestinal Diseases; Intestines; Laboratories; Lamina Propria; Ligands; Measures; Mediating; Metabolism; Microbe; Modeling; Morbidity - disease rate; Mouse Strains; Mus; Nosocomial Infections; Pathogenesis; Pathology; Patients; Population; Predisposition; Prevention strategy; Recombinant DNA; Recurrence; Reporter; Reproduction spores; Resistance; Role; Route; Signal Transduction; TLR5 gene; TLR7 gene; Taxon; Time; Toxic Megacolon; United States; antimicrobial; antimicrobial peptide; bile salts; cancer therapy; commensal microbes; design; in vivo; insight; microbial; monocyte; mortality; novel; prevent; pyrosequencing; receptor; reconstitution; resiquimod

DESCRIPTION (provided by applicant): Clostridium difficile causes colitis following antibiotic-mediated perturbation of the intestinal microbiota. C. difficile causes over 500,000 infections per year, with an estimated 15,000 deaths annually in the United States. Ingestion of infectious spores from contaminated environments represents the major route by which this infection is acquired. Very little is known about interactions between C. difficile and the normal intestinal microbiota or with the host innate immune system. Our laboratory has investigated C. difficile infection in antibiotic treated mice and demonstrated that stimulating TLR-5 with bacterial flagellin or TLR7/8 with resiquimod markedly enhances resistance to C. difficile infection. We have also demonstrated that a single dose of clindamycin results in prolonged susceptibility to C. difficile infection. The goal of this project is to characterize innate immune defenses, includig those induced by the commensal microbial flora, in protection against C. difficile infection. The first aim is to characterize the mechanism by which stimulation of TLR5 by flagellin or TLR7/8 by resiquimod enhances resistance to C. difficile infection. We will investigate the role IL22, the arl hydrocarbon receptor and primary and secondary bile salts in TLR-mediated defense against C. difficile infection. The second aim is to determine whether intestinal dendritic cells or inflammatory monocytes contribute to resistance to C. difficile infection. We will use CCR2-reporter and CCR2-depletor mice that were generated in our laboratory to determine the impact of inflammatory monocytes on the pathogenesis of C. difficile colitis. The third aim is to determine the effect of different antibiotic treatments on the composition of the intestinal microbial flora. We will use the Roche 454 massively parallel pyrosequencing platform to determine microbial complexity in the GI tract, and to correlate changes in the flora with susceptibility to C. difficile infection. Mice will be reconstituted with fractionated intestinal microbiota and resistance to C. difficile infection will be measured. These studies will identify microbial populations that inhibit germination and/or vegetative growth of C. difficile. Our ultimate goal is to identify the in vivo mechanisms protecting the host from C. difficile infection and to discover practicable approaches, such as selective TLR or cytokine receptor stimulation or microbiota manipulation, to re-induce these mechanisms in vulnerable patients.

描述（由申请人提供）：艰难梭菌在抗生素介导的肠菌群扰动后引起结肠炎。艰难梭菌会导致超过500,000的感染 一年，估计在美国每年有15,000人死亡。从受污染的环境中摄入传染性孢子代表了获得这种感染的主要途径。关于艰难梭菌与正常肠道菌群或与宿主先天免疫系统之间的相互作用知之甚少。我们的实验室研究了抗生素治疗的小鼠艰难梭菌感染，并证明用细菌鞭毛蛋白或TLR7/8刺激TLR-5具有重生的抗生素，显着增强了对艰难梭菌感染的抗性。我们还证明，单一剂量的克林霉素会导致艰难梭菌感染的敏感性延长。该项目的目的是表征先天免疫防御措施，包括由共生微生物菌群引起的，以防止艰难梭菌感染。第一个目的是表征鞭毛蛋白或TLR7/8刺激TLR5的机制，从而增强了对艰难梭菌感染的抗性。我们将研究在TLR介导的艰难梭菌感染的防御中，IL22，ARL烃受体以及原发性和继发性胆汁盐。第二个目的是确定肠道树突状细胞或炎症单核细胞是否有助于艰难梭菌感染。我们将使用我们实验室中产生的CCR2-Reporter和CCR2-驱虫小鼠，以确定炎症单核细胞对艰难梭菌结肠炎发病机理的影响。第三个目的是确定不同抗生素处理对肠道微生物菌群组成的影响。我们将使用Roche 454大量平行的焦磷酸测序平台来确定胃肠道中的微生物复杂性，并将植物群的变化与艰难梭菌感染的敏感性相关联。小鼠将用分离的肠道微生物群来重构，并将测量对艰难梭菌感染的耐药性。这些研究将确定抑制艰难梭菌发芽和/或营养生长的微生物种群。我们的最终目标是确定保护宿主免受艰难梭菌感染的体内机制，并发现可行的方法，例如选择性的TLR或细胞因子受体刺激或微生物群操纵，以重新诱导脆弱患者中的这些机制。