The physiological activation and consequences of Toxin-Antitoxin systems in Salmonella

沙门氏菌毒素-抗毒素系统的生理激活和后果

• 批准号: 10295585
• 负责人: Sophie Helaine
• 金额: $ 50.69万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-07 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10295585
• 关键词: Acetylation; Address; Affect; Amino Acyl Transfer RNA; Antibiotics; Antimicrobial Resistance; Bacteria; Bacteriophages; Biochemical; Biology; Cell physiology; Cells; Cellular Immunity; Complex; Crystallization; Development; Disputes; Elements; Environment; Equilibrium; Event; Exposure to; Family; Foundations; Genes; Genetic; Glean; Glycine; Growth; Heterogeneity; Immune; Immunity; In Vitro; Infection; Intoxication; Knowledge; Lead; Light; Molecular; Mutagenesis; Mycobacterium tuberculosis; Operon; Phenotype; Physiological; Process; Proteins; Pseudomonas aeruginosa; Relapse; Reporting; Repression; Repressor Proteins; Resolution; Role; Salmonella; Salmonella typhimurium; Scientist; Specificity; Stimulus; Stress; Structure; System; Therapeutic; Toxin; Transfer RNA; Translations; Work; antitoxin; base; gene repression; genetic approach; imaging approach; in vivo; insight; macrophage; paralogous gene; pathogen; persistent bacteria; promoter; resilience; response; structural biology; uptake

PROJECT SUMMARY/ABSTRACT Bacteria control their growth in response to environmental challenges and sometimes enter a growth arrested state. Growth-arrested bacteria often show remarkable abilities to survive exposure to antibiotics and are known as antibiotic persisters. These bacterial persisters are thought to contribute to the relapse of many infections and to the worrying burden of antimicrobial resistance. Understanding how bacteria establish this growth arrested state can help to develop better antibiotics. Toxin-Antitoxin (TA) modules are widespread pairs of genes involved in bacterial growth control. They are stress responsive systems that enable bacteria to adapt their growth in response to insults such as attack by phage or host immune defense cells. TA systems encode a non- secreted toxin which inhibits an essential cellular function thereby controlling growth, and an antitoxin that neutralizes the toxin. The antitoxin exerts control over the toxin at two levels, through repression of expression and direct neutralization. It is thought that upon stress, the antitoxin is degraded, on one hand de-repressing expression of the operon, and on the other hand liberating the toxin. However, despite numerous studies on toxin functions, very little information is available on how stresses lead to activation of TA systems, from “de- repression” of the TA operon and liberation of the toxin to actual consequences of the activity of the toxin on the bacteria; and the role of these ubiquitous elements remains disputed. The foundation of the work is our prior demonstration that uptake of Salmonella Typhimurium by macrophages is a natural trigger of expression and activity of each of the TA modules encoded by the bacteria. Using a combination of genetic, biochemical, structural and imaging approaches, we will take advantage of this powerful trigger to study how TA systems of the TacAT group are activated (de-repression in aim 1 and liberation of the toxin in aim 2) and the physiological consequences of the activity of Tac toxins in response to attacks inflicted on bacteria by their environment (intoxication in aim 3 and effects of intoxication in aim 4). The knowledge generated will undoubtedly provide insight on other TA systems beyond the Tac family. In addition, it has the potential to transform our understanding of bacterial growth heterogeneity and the associated phenomenon of antibiotic persistence and serve as a springboard to develop better antibiotics.

项目概要/摘要 细菌为了应对环境挑战而控制其生长，有时会进入生长停滞状态 状态。生长停滞的细菌通常表现出非凡的能力，能够在接触抗生素的情况下生存，并且众所周知 作为抗生素持续者。这些细菌持续存在被认为会导致许多感染的复发和 令人担忧的抗菌素耐药性负担。了解细菌如何实现这种生长抑制 国家可以帮助开发更好的抗生素。毒素-抗毒素 (TA) 模块是广泛存在的基因对 参与细菌生长控制。它们是压力响应系统，使细菌能够适应它们的 响应噬菌体或宿主免疫防御细胞攻击等损伤而生长。 TA 系统编码非 分泌的毒素抑制基本细胞功能从而控制生长，以及抗毒素 中和毒素。抗毒素通过抑制表达在两个层面上控制毒素 以及直接中和。人们认为，在压力下，抗毒素会被降解，一方面可以解除抑制 一方面表达操纵子，另一方面释放毒素。然而，尽管有大量研究 毒素功能，关于压力如何导致TA系统激活的信息很少，从“de- TA操纵子的抑制和毒素的释放对毒素活性对 细菌;这些无处不在的元素的作用仍然存在争议。工作的基础是我们的先决条件 证明巨噬细胞摄取鼠伤寒沙门氏菌是表达和表达的自然触发因素 细菌编码的每个 TA 模块的活性。结合遗传、生化、 结构和成像方法，我们将利用这个强大的触发器来研究 TA 系统如何 TacAT 组被激活（目标 1 中去抑制，目标 2 中毒素释放），并且生理学 Tac 毒素的活性对环境对细菌造成的攻击作出反应的后果 （目标 3 中的中毒和目标 4 中的中毒影响）。所产生的知识无疑将提供 对 Tac 系列以外的其他 TA 系统的深入了解。此外，它还有可能改变我们的 了解细菌生长异质性和抗生素持久性的相关现象 作为开发更好抗生素的跳板。