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: 10418802
• 负责人: Sophie Helaine
• 金额: $ 50.83万
• 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/10418802
• 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.

项目摘要/摘要 细菌控制着对环境挑战的响应，有时会进入被捕的增长 状态。生长避难的细菌通常表现出显着的能力，可以在暴露于抗生素的情况下生存，并且已知 作为抗生素的坚持。人们认为这些细菌的坚持有助于缓解许多感染和 令人担忧的抗菌耐药性燃烧。了解细菌如何确定这种增长被逮捕 州可以帮助发展更好的抗生素。毒素 - 抗毒素（TA）模块是广泛的基因对 参与细菌生长控制。它们是压力响应系统，使细菌能够适应其 响应于侮辱（例如噬菌体攻击或宿主免疫防御细胞）的增长。 TA系统编码非 - 分泌的毒素，抑制必不可少的细胞功能，从而控制生长，以及一种抗毒素的毒素 中和毒素。抗毒素通过表达在两个层次上对毒素施加控制 和直接谈判。据认为，在压力下，抗毒素会降解，一只手去抑制 歌剧的表达，另一方面解放了毒素。但是，许多研究 毒素功能，很少有关于应力如何导致TA系统激活的信息，从 抑制ta歌剧和毒素对毒素活动的实际后果的解放 细菌;这些无处不在的元素的作用仍然存在争议。这项工作的基础是我们的先前 证明巨噬细胞对鼠伤寒沙门氏菌的吸收是表达的自然触发因素， 由细菌编码的每个TA模块的活性。结合遗传，生化， 结构性和成像方法，我们将利用这种强大的触发器来研究 塔卡特组被激活（AIM 1中的抑制和AIM 2中的毒素解放）和生理学 TAC毒素活性对细菌对细菌造成的攻击的影响 （AIM 3中的中毒和AIM 4中氧基化的影响）。产生的知识无疑会提供 对TAC家族以外的其他TA系统的了解。此外，它有可能改变我们的 了解细菌生长异质性以及抗生素持久性和相关现象 用作开发更好抗生素的跳板。