Copper Sensing in Uropathogenic Escherichia coli

项目总结 意义：尿路感染是最常见的成人细菌感染，每年影响 全球超过1.5亿人。作为抗生素处方的一个常见原因，尿路感染被认为是 抗菌剂耐药性的重要来源。因此，提高了对相互作用的理解 尿路感染时宿主与病原体之间的关系对于促进新的治疗方法的发展至关重要 探员们。作为一种保护策略，急性感染期间尿铜浓度会增加5倍。 对抗病原体。在尿路感染后，大部分铜在肠道中排泄，尿路病原体在肠道中定居。 形成了反复感染的基础。尿路致病性大肠杆菌(UPEC)，最常见的原因是 UTIS，使用铜外流和隔离机制来防止铜中毒。此外，UPEC居住在 寄主体内铜含量和氧气含量不同的多个生态位(肠道、阴道和膀胱) 集中精神。虽然铜的反应机制已经在实验室菌株中得到了表征，但 每个铜反应系统对宿主UPEC持久性的相对贡献尚未阐明。 这一提议将决定UPEC对铜和铜的时空诱导和调节 将定义每个响应系统在调解主机中的UPEC持久性方面的作用。 理论基础和假设：为了成功感染尿路，UPEC必须耐受 铜含量。同样，UPEC必须耐受肠道铜的排泄，以定植宿主肠道，并有可能 导致再次感染。根据先前的研究，铜响应的UPEC基因座cus是最多的 上调了急性人类尿路感染样本中的所有基因。Cus轨迹编码两个组分 信号系统CusSR、铜感应和响应信号系统以及铜排出装置 CusCFBA。此外，铜响应系统CueR/COPA在好氧条件下促进铜出口。 氧的有效性是铜反应系统在大肠杆菌中优先活跃的关键决定因素 对铜的氧化状态和铜外流的能量要求。氧气水平变化很大， UPEC的利基市场。我假设氧气的可用性和铜的水平决定了铜的反应 在UPEC殖民和感染的解剖利基中活跃的系统。我提出了两个目标来测试 这个假设是： 目标：AIM 1将确定哪些UPEC铜反应系统在解剖壁龛(阴道， 肠，膀胱)，UPEC遇到。目标2将研究CusSR在介导铜敏感中的作用 以及对厌氧肠道的耐受性。 影响：这些研究将首次解决铜响应系统的层级和本地化问题 泌尿病因学。澄清UPEC如何感知和响应铜将提供对 靶向UPEC的铜解毒方法是治疗和预防尿路感染的一种可行的治疗方案。

PROJECT SUMMARY Significance: Urinary tract infections (UTIs) are the most common adult bacterial infection annually affecting over 150 million individuals worldwide. As a common reason for antibiotic prescriptions, UTIs are considered a substantial source of resistance to antimicrobial agents. Thus, improved understanding of the interactions between host and bacterial pathogen during UTI is essential for facilitating the development of new therapeutic agents. The concentration of copper increases 5-fold in the urine during acute infection as a protective strategy against the pathogen. Most copper is excreted in the intestines where uropathogens colonize following UTI forming the basis for recurrent infections. Uropathogenic Escherichia coli (UPEC), the most common cause of UTIs, uses copper efflux and sequestration mechanisms to prevent copper toxicity. Additionally, UPEC inhabits multiple niches (intestines, vagina, and bladder) throughout the host that vary in copper content and oxygen concentration. While copper response mechanisms have been characterized in laboratory strains of E. coli, the relative contribution of each copper response system to UPEC persistence in the host has not been elucidated. This proposal will determine the spatio-temporal induction and regulation of the UPEC response to copper and will define the role of each response system in mediating UPEC persistence in the host. Rationale and Hypothesis: In order to successfully infect the urinary tract, UPEC must tolerate increased copper levels. Similarly, UPEC must tolerate intestinal copper excretion to colonize the host gut and potentially cause re-infections. Based on prior studies, the copper responsive UPEC locus cus is among the most upregulated of all genes in samples from acute human UTIs. The cus locus encodes the two-component signaling system CusSR, a copper sensing and response signaling system, and copper efflux apparatus CusCFBA. Additionally, the copper response systems CueR/CopA facilitate copper export in aerobic conditions. Oxygen availability is a key determinant of which copper response system is preferentially active in E. coli due to the oxidation state of copper and energetic requirements for copper efflux. Oxygen levels vary widely within UPEC’s niches. I hypothesize that oxygen availability and copper levels dictate the copper response systems that are active in the anatomic niches that UPEC colonizes and infects. I propose two aims to test this hypothesis: Aims: Aim 1 will determine which UPEC copper response systems are active in the anatomic niches (vagina, intestines, bladder) that UPEC encounters. Aim 2 will investigate the role of CusSR in mediating copper sensing and tolerance in the anaerobic intestinal niche. Impact: These studies will be the first to address the hierarchy and localization of copper response systems uropathogenesis. Clarification of how UPEC senses and responds to copper will provide insight into whether targeting copper detoxification methods of UPEC is a viable therapeutic option for UTI treatment and prevention.