Antibiotic Recognition and Signaling in Vancomycin-Resistant Enterococci (VRE)

耐万古霉素肠球菌 (VRE) 中的抗生素识别和信号转导

• 批准号: 10304192
• 负责人: Patrick J Loll
• 金额: $ 38.87万
• 依托单位: DREXEL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10304192
• 关键词: Address; Adjuvant; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Binding; Biochemical; Biophysics; Cell Wall; Clinical; Communities; Cytoplasm; Detection; Development; Elements; Enterococcus; Enzymes; Genes; Genetic Transcription; Genotype; Hospitals; Human; Immune; In Vitro; Infection; Length; Lipids; Maps; Membrane; Microbe; Microbiology; Molecular; Nosocomial Infections; Operon; Organism; Outcome; Pathogen detection; Pathway interactions; Patients; Phenotype; Phosphorylation; Protein Dephosphorylation; Proteins; Public Health; Refractory; Resistance; Resort; Signal Transduction; Soil; Stress; Structure; System; Therapeutic; Time; Vancomycin; Vancomycin Resistance; Vancomycin resistant enterococcus; Work; World Health Organization; X-Ray Crystallography; clinically relevant; combat; drug testing; experimental study; insight; novel; pathogen; protein-histidine kinase; reconstitution; resistance gene; sensor; sensor histidine kinase; transcription factor; transposon/insertion element

PROJECT SUMMARY The rise of antibiotic resistance in hospital-acquired enterococcal pathogens constitutes a serious clinical threat. In particular, enterococci are now extremely likely to display resistance to vancomycin, which has historically functioned as the antibiotic of last resort for these pathogens, leaving the clinician with few viable therapeutic options. Vancomycin resistance in these organisms invariably involves the acquisition of resistance operons encoded on mobile DNA elements. These operons (which are ultimately derived from antibiotic-producing soil microbes) encode enzymes that remodel the bacterial cell wall, and thereby confer resistance to the antibiotic. Importantly, expression of these remodeling enzymes is controlled by a two- component system, VanS/VanR, that senses the presence of the antibiotic and responds to this signal by increasing transcription of the resistance genes. Little is known about how VanS, the sensor histidine kinase of this two-component system, detects vancomycin; indeed, fundamental details remain obscure, including whether VanS directly binds vancomycin, or whether it instead detects some downstream consequence of vancomycin action. This proposal focuses on the two main forms of vancomycin-resistant enterococci (VRE) found in patients, namely A- and B-type resistance. Using a combination of biochemical, biophysical, and microbiological approaches, the proposed experiments will address the molecular mechanisms underlying antibiotic recognition in these two types of VRE. The proposal builds upon preliminary observations revealing that the A and B resistance phenotypes appear to rely on fundamentally different mechanisms of antibiotic sensing. Hence, one Aim will focus on the VanS protein from B-type enterococci (VanSB), which is shown to bind directly to vancomycin. The details underlying this interaction will be elucidated, as will the effects of antibiotic action upon the enzymatic activities of VanSB. A second Aim focuses on VanSA, which does not respond directly to the antibiotic. Accordingly, the precise identity of the activating signal will be probed. A third Aim will provide structural information about the VanS and VanR proteins, in order to inform and direct the functional efforts. Overall, the proposed work will yield fundamental insights into the functioning of an antibiotic-sensing pathway; provide potential entry points for the rational redesign of therapeutics that will enable them to evade detection by pathogens; and inform the development of antibiotic adjuvants that can overcome bacterial surveillance systems and restore efficacy to well-tested drugs such as vancomycin.

项目摘要 医院获得的肠球菌病原体中抗生素耐药性的兴起构成了严重的临床 威胁。特别是，肠球菌现在极有可能表现出对万古霉素的抗性， 历史上充当这些病原体的最后手段的抗生素，使临床医生几乎没有生存 治疗选择。这些生物中的万古霉素抗性总是涉及获取 在移动DNA元件上编码的电阻操纵子。这些操纵子（最终是从 产生抗生素的土壤微生物）编码重塑细菌细胞壁的酶，从而赋予 对抗生素的抗性。重要的是，这些重塑酶的表达受到两种 组件系统，Vans/vanr，感知抗生素的存在，并通过 抗性基因的转录增加。关于传感器组氨酸激酶的货车如何了解 在这个两个组件系统中，检测万古霉素；确实，基本细节仍然晦涩，包括 Vans是否直接结合万古霉素，还是检测到的某些下游结果 万古霉素作用。该提案重点介绍了万古霉素抗肠球菌（VRE）的两种主要形式 在患者中发现，即A-和B型耐药性。结合生化，生物物理和 微生物学方法，提出的实验将解决基础的分子机制 这两种类型的VRE中的抗生素识别。该提案建立在初步观察的基础上 A和B抗性表型似乎依赖于根本不同的抗生素机制 感应。因此，一个目标将重点放在B型肠球菌（VANSB）的VAN蛋白上，该蛋白显示为 直接与万古霉素结合。这种相互作用的细节将被阐明，以及 VANSB酶促活性的抗生素作用。第二个目标重点是Vansa，而不是 直接对抗生素反应。因此，将探测激活信号的精确身份。一个 第三目的将提供有关VAN和VANR蛋白的结构信息，以告知和指导 功能努力。总体而言，拟议的工作将产生基本的见解 抗生素感应途径；为理性的治疗方法提供潜在的切入点 使他们能够通过病原体逃避检测；并告知可以开发的抗生素佐剂 克服细菌监测系统，并恢复对诸如万古霉素等经过良好测试药物的功效。