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

基本信息

批准号：
10062476
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
项目类别：
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/10062476
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

项目摘要

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.

项目概要医院获得性肠球菌病原体抗生素耐药性的上升构成了严重的临床问题威胁。特别是，肠球菌现在极有可能对万古霉素表现出耐药性，而万古霉素已历史上，抗生素是这些病原体的最后手段，给临床医生留下了很少的生存空间。治疗选择。这些生物体中的万古霉素耐药性总是涉及获得编码在移动DNA元件上的抗性操纵子。这些操纵子（最终源自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耐药性。重要的是，这些重塑酶的表达是由两个- VanS/VanR 组件系统可感知抗生素的存在并通过以下方式响应此信号：增加抗性基因的转录。人们对VanS（组氨酸激酶传感器）如何运作知之甚少。该双组分系统检测万古霉素；事实上，基本细节仍然模糊不清，包括 VanS 是否直接结合万古霉素，或者是否检测到万古霉素的某些下游结果万古霉素作用。该提案重点关注两种主要形式的耐万古霉素肠球菌 (VRE) 在患者中发现的，即A型和B型耐药。结合使用生物化学、生物物理和微生物学方法，拟议的实验将解决潜在的分子机制这两类 VRE 中抗生素的识别。该提案建立在初步观察的基础上，揭示了 A 和 B 耐药表型似乎依赖于根本不同的抗生素机制传感。因此，一个目标将集中于 B 型肠球菌 (VanSB) 的 VanS 蛋白，该蛋白被证明可以直接与万古霉素结合。将阐明这种相互作用背后的细节，以及所产生的影响抗生素对 VanSB 酶活性的作用。第二个目标侧重于 VanSA，但它并不直接对抗生素产生反应。因此，将探测激活信号的精确身份。一个第三个目标将提供有关 VanS 和 VanR 蛋白的结构信息，以便告知和指导功能性努力。总体而言，拟议的工作将为了解一个系统的运作提供基本见解。抗生素传感途径；为合理重新设计治疗方法提供潜在的切入点使它们能够逃避病原体的检测；并为抗生素佐剂的开发提供信息克服细菌监测系统并恢复万古霉素等经过充分测试的药物的功效。