Elucidating the mechanisms of transient polymyxin resistance in pathogenic E. coli.

阐明致病性大肠杆菌瞬时多粘菌素耐药机制。

• 批准号: 10224796
• 负责人: Melanie N Hurst
• 金额: $ 2.49万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2022-05-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10224796
• 关键词: Anogenital region; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Attention; Bacteria; Bacterial Chromosomes; Base Sequence; Cations; Cells; Code; Cues; Data; Disease; Elements; Ensure; Enterobacteriaceae; Environment; Enzymes; Escherichia coli; Event; Exhibits; Frequencies; Genes; Genetic; Genetic Transcription; Genome; Genomics; Goals; Heterogeneity; Immune; In Vitro; Individual; Infection; Iron; Lead; Lipid A; Membrane; Minimum Inhibitory Concentration measurement; Modification; Molecular Biology; OmpR protein; Operating System; Output; Pathogenicity; Phosphotransferases; Phylogenetic Analysis; Polymyxin B; Polymyxin B resistance; Polymyxin Resistance; Population; Probiotics; Property; Receptor Signaling; Recurrence; Regulation; Regulon; Reporter; Reporting; Research; Resistance; Resort; Role; Salmonella; Signal Transduction; Signal Transduction Pathway; Specificity; Stress; System; Testing; Transcriptional Activation; Untranslated RNA; Up-Regulation; Urethra; Urinary tract; Urinary tract infection; Uropathogenic E. coli; Virulence; Work; antimicrobial; bacterial fitness; bacterial resistance; colistin resistance; extracellular; fitness; flexibility; genetic element; genome-wide analysis; global health; gut colonization; insight; interdisciplinary approach; member; microbial; mouse model; pathogenic Escherichia coli; pathogenic bacteria; polypeptide; prevent; programs; protein-histidine kinase; resistance mechanism; response; sensor; sensor histidine kinase

Defining Differences in how LPS modification is Regulated in Different E. coli pathotypes Project Summary Cells encounter a constant barrage of extracellular cues to which they respond using only the finite number of signal transduction pathways encoded within their genome. While we understand how individual signal transduction systems operate, little is known about how distinct signaling systems interact to integrate information and/or expand their signal responses. The overall goal of this project is to understand how signaling flexibility benefits the responses of different E. coli strains to cationic polypeptides. Although much attention is placed on the acquisition of antibiotic resistance markers by the Enterobacteriaceae, there is increasing evidence that bacteria can also mount transient resistance to antibiotics via the upregulation of chromosomally encoded markers. For example, the pmrC gene encoded by Salmonella spp and E. coli species is an orthologue of the mcr-1 gene that imparts resistance to colistin antibiotics. We have recently demonstrated that transient resistance to polymyxin B arises in strains of uropathogenic E. coli, following stimulation with ferric iron. We subsequently found that the transient polymyxin B resistance is brought about via the activation of the PmrB sensor kinase, a member of the PmrAB two-component system (TCS). Bacterial TCSs comprise a membrane- embedded histidine kinase that is the signal receptor, and a response regulator protein that directs the corresponding cellular changes. Although there are sequence-based determinants that dictate specificity among cognate TCS partners, we discovered strong interactions between the PmrAB and QseBC TCSs, in which the PmrB histidine kinase readily activates both its cognate partner PmrA and the non-cognate response regulator QseB in response to ferric iron, leading to a 16-fold increase in the MIC. I hypothesize that coordinated regulation of PmrA and QseB leads to upregulation of genes critical for lipid A modification that in turn protects bacteria from the insults of polymyxin B and other cationic polypeptides. I will test this hypothesis in three aims, in which I will: (1) Define the PmrA and QseB regulons in response to polymyxin B and define the mechanism by which PmrA and QseB activation leads to polymyxin B resistance. (2) Determine how the QseBC and PmrAB interactions have evolved to benefit bacterial fitness in different niches, and; (3) Ascertain how the amount of conservation present in the QseBC-PmrAB signaling cascade in E. coli strains from different phylogenetic clades and with different pathogenic strategies. Towards these goals, an inter-disciplinary approach will be followed, encompassing molecular biology, genome-wide analyses of transcription and robust murine models of infection. Combined these studies will provide mechanistic details into a mechanism that allows bacteria to survive one of the last resort antibiotics and will provide insights into the conservation of the QseBC- PmrAB circuitry in different E. coli pathotypes.

定义不同大肠杆菌致病型中 LPS 修饰调节方式的差异 项目概要 细胞遇到持续不断的细胞外信号，它们仅使用有限数量的信号做出反应 其基因组中编码的信号转导途径。虽然我们了解个体信号如何 转导系统如何运作，人们对不同信号系统如何相互作用整合知之甚少 信息和/或扩展其信号响应。该项目的总体目标是了解信号如何传递 灵活性有利于不同大肠杆菌菌株对阳离子多肽的反应。虽然备受关注 越来越多的证据表明肠杆菌科细菌获得抗生素抗性标记 细菌还可以通过染色体编码的上调对抗生素产生短暂的耐药性 标记。例如，沙门氏菌和大肠杆菌编码的 pmrC 基因是 mcr-1 基因赋予粘菌素抗生素耐药性。我们最近证明了瞬态 在三价铁刺激后，泌尿道致病性大肠杆菌菌株会产生对多粘菌素 B 的耐药性。我们 随后发现短暂的多粘菌素 B 耐药是通过 PmrB 的激活引起的 传感器激酶，PmrAB 双组分系统 (TCS) 的成员。细菌 TCS 包含膜 嵌入的组氨酸激酶是信号受体，以及指导反应的反应调节蛋白 相应的细胞变化。尽管存在基于序列的决定因素决定了之间的特异性 同源 TCS 合作伙伴，我们发现 PmrAB 和 QseBC TCS 之间存在很强的相互作用，其中 PmrB 组氨酸激酶很容易激活其同源伙伴 PmrA 和非同源反应调节因子 QseB 对三价铁的反应，导致 MIC 增加 16 倍。我假设协调监管 PmrA 和 QseB 会导致对脂质 A 修饰至关重要的基因上调，从而保护细菌 免受多粘菌素 B 和其他阳离子多肽的侵害。我将从三个目标来检验这个假设，其中 我将： (1) 定义响应多粘菌素 B 的 PmrA 和 QseB 调节子，并定义其机制 PmrA 和 QseB 激活导致多粘菌素 B 耐药。 (2) 确定QseBC和PmrAB如何 相互作用的发展有利于不同生态位的细菌适应性； (3) 确定金额 来自不同系统发育分支的大肠杆菌菌株中 QseBC-PmrAB 信号级联中存在的保守性 并具有不同的致病策略。为了实现这些目标，将遵循跨学科的方法， 涵盖分子生物学、全基因组转录分析和强大的小鼠感染模型。 这些研究相结合，将为细菌在其中一种环境下生存的机制提供机制细节。 抗生素的最后手段，并将提供有关 QseBC-PmrAB 电路在不同环境下的保护的见解 大肠杆菌致病型。