Global regulation in Clostridium difficile via phase variation of cyclic diguanylate signaling

通过环二鸟苷酸信号传导的相位变化对艰难梭菌进行全局调控

• 批准号: 10231171
• 负责人: RITA TAMAYO
• 金额: $ 49.84万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-18 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10231171
• 关键词: Affect; Anaerobic Bacteria; Animal Model; Antibiotic Therapy; Antibiotics; Antigens; Attenuated; Behavior; Biochemical; Biochemistry; Cell Surface Proteins; Cell Wall; Cell surface; Cells; Cessation of life; Clostridium difficile; Cytotoxin; DNA; DNA Sequence; Data; Development; Diarrhea; Disease; Ensure; Environment; Enzymes; Flagella; Gene Expression; Gene Expression Regulation; Genetic; Global Change; Goals; Growth; Health Care Costs; Heterogeneity; Human; Hydrolase; Immune; Infection; Intestines; Laboratories; Life Style; Link; Mediating; Microbial Biofilms; Mission; Modification; Molecular; Molecular Biology; Molecular Genetics; Morphology; Names; Nosocomial Infections; Operon; Outcome; Pathogenicity; Periodicity; Phase; Phenotype; Physiological; Physiology; Pilum; Play; Population; Preventive; Production; Proteins; Pseudomembranous Colitis; Public Health; Recurrence; Regulation; Regulon; Research; Resources; Role; Signal Transduction; Signaling Molecule; Surface; Symptoms; System; Techniques; Testing; Therapeutic; Toxin; United States National Institutes of Health; Variant; Virulence; Work; bacterial genetics; cell behavior; cell motility; combat; extracellular; fitness; gene function; gut colonization; immunogenic; pathogen; pathogenic bacteria; pressure; protein function; recombinase; response

PROJECT SUMMARY Clostridium difficile is a major public health threat, causing disease ranging from mild diarrhea to potentially fatal pseudomembranous colitis. C. difficile disease symptoms are largely mediated by the secreted cytotoxins, TcdA and TcdB. Many aspects of the pathogenicity of this bacterium remains poorly understood, including how C. difficile adapts to the host intestinal environment. The components of the bacterial cell surface play critical roles in physiology and virulence and are commonly immunogenic antigens and potential antibiotic targets. In C. difficile the signaling molecule cyclic diguanylate (c-di-GMP) controls the production of flagella, type IV pili, and multiple additional cell surface proteins, indicating a key role for c-di-GMP in reorganizing the C. difficile cell surface in response to the host intestinal environment. Phase variation is a means by which many bacterial species introduce phenotypic heterogeneity into the population as a strategy to ensure survival of the population in the face of changing selective pressures. We recently showed that flagella and toxins phase vary in C. difficile, and sequencing analyses identified several other putative phase variable loci including two that encode c-di-GMP hydrolases. Our central hypothesis is that C. difficile combines c-di-GMP signaling and phase variation to coordinate global changes to the cell surface, enabling adaptation to extracellular pressures encountered during colonization of the intestinal tract. The objective of this proposal is to define the mechanisms of phase variation that control c-di-GMP signaling, the phenotypic responses to changes in c-di- GMP, and the impact of these regulatory mechanisms on C. difficile physiology and virulence. To accomplish this goal, we employ molecular genetics, biochemical techniques, and animal models of C. difficile disease to examine phase variation and c-di-GMP signaling at the population and single cell levels. Our discovery that C. difficile links phase variation with c-di-GMP signaling reveals a previously unknown mechanism for coordinated modification of the bacterial cell surface. Completion of these aims may expose new targets for attenuating C. difficile fitness in the host, facilitating efforts to combat this increasingly problematic pathogen.

项目概要 艰难梭菌是一个主要的公共卫生威胁，引起从轻度腹泻到潜在的疾病。 致命的伪膜性结肠炎。艰难梭菌疾病症状主要是由分泌的细胞毒素介导的， TcdA 和 TcdB。这种细菌的致病性的许多方面仍然知之甚少，包括如何 艰难梭菌适应宿主肠道环境。细菌细胞表面的成分至关重要 在生理学和毒力中发挥作用，通常是免疫原性抗原和潜在的抗生素靶点。在 艰难梭菌信号分子环二鸟苷酸 (c-di-GMP) 控制鞭毛、IV 型菌毛、 和多种额外的细胞表面蛋白，表明 c-di-GMP 在重组艰难梭菌中发挥着关键作用 细胞表面对宿主肠道环境做出反应。相变是许多细菌 物种将表型异质性引入种群，作为确保物种生存的策略 人口面临不断变化的选择压力。我们最近表明鞭毛和毒素的相位不同 在艰难梭菌中，测序分析确定了其他几个假定的相位可变基因座，其中两个 编码 c-di-GMP 水解酶。我们的中心假设是艰难梭菌结合了 c-di-GMP 信号传导和 相位变化协调细胞表面的整体变化，从而能够适应细胞外压力 肠道定植期间遇到的。该提案的目标是定义 控制 c-di-GMP 信号传导的相变机制，对 c-di- 变化的表型反应 GMP，以及这些调节机制对艰难梭菌生理学和毒力的影响。为了完成 为了实现这一目标，我们采用分子遗传学、生化技术和艰难梭菌疾病动物模型来 检查群体和单细胞水平的相位变化和 c-di-GMP 信号传导。我们的发现是 C. difficile 与 c-di-GMP 信号传导的相位变化揭示了一种以前未知的协调机制 细菌细胞表面的修饰。完成这些目标可能会揭示减少艰难梭菌的新目标。 艰难梭菌在宿主体内的适应性，有助于对抗这种日益成问题的病原体。