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

基本信息

批准号：
10020308
负责人：
RITA TAMAYO
金额：
$ 50.85万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
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/10020308
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

项目摘要

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标。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可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。这些目标的完成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。