E. coli virulence gene expression during clinical UTIs in women

 描述(申请人提供)：尿路是最常见的细菌感染部位之一，而大肠杆菌是目前为止感染该部位最常见的物种。大多数关于尿路致病性大肠杆菌(UPEC)毒力基因表达的数据来自体外研究或小鼠尿路感染模型(UTI)。为了纠正这一点，我们测量了从出现简单尿路感染的妇女身上收集并立即稳定下来的尿液中大肠杆菌的全球基因表达。这些新的RNAseq数据使我们能够专注于在人类感染期间表达最高的毒力机制。我们的长期研究目标是了解UPEC如何定植人类尿路，避免免疫反应，并损害宿主。在这一资助期间的目标是确定在人类宿主中被发现特异性上调的毒力基因在致病中的作用。我们的核心假设是UPEC菌株的毒力是其附着、铁获取、毒素产生和特定代谢物运输能力的总和，这一假设得到了我们对UPEC在UTI期间全球基因表达模式的测量的支持，这些基因表达模式是在密歇根大学大学卫生服务诊所就诊的五名女性中出现的膀胱炎症状。这项拟议工作的基本原理是，一旦我们确定了人类尿路感染期间表达最高的毒力基因，我们就可以将重点放在针对这些特定目标的干预和预防上。我们将验证我们的中心假设，并通过实现两个具体目标来完成我们的目标：1)确定人类尿路感染期间致尿路感染大肠杆菌的代表性转录组；以及2)确定新发现的在感染女性尿路感染的大肠杆菌中上调的毒力决定因素的致病机制。实施这些目标的预期结果将是对全球基因表达和宿主特异性毒力基因在女性感染期间上调的准确评估，而不是在尿液或富含介质的体外培养期间。这些研究的积极影响将是巨大的。我们将精确量化UPEC基因在其他健康女性感染期间的表达。我们将确定新发现的毒力因子在大肠杆菌尿路感染过程中的作用机制。我们会 还要了解哪些毒力决定因素在简单的人类尿路感染中同时存在和表达，以及它们表达的程度。了解这种细菌用来定植人类尿路、避免免疫反应和损害宿主的毒力因子，将为预防反复尿路感染女性和那些首次感染尿路感染易感女性的这种公共卫生祸害打开大门。

 DESCRIPTION (provided by applicant): The urinary tract is among the most common sites of bacterial infection and E. coli is by far the most common species infecting this site. Most data regarding expression of uropathogenic E. coli (UPEC) virulence genes have come from in vitro studies or the murine model of urinary tract infection (UTI). To remedy this, we have measured global gene expression from E. coli in urine collected and stabilized immediately from women presenting with uncomplicated UTI. These new RNAseq data allow us to focus on the most highly expressed virulence mechanisms active during human infection. Our long term research goal is to understand how UPEC colonize the human urinary tract, avoid the immune response, and damage the host. The objective during this funding period is to determine the contribution to pathogenesis of the virulence genes found to be specifically upregulated in the human host. Our central hypothesis, that the virulence of a UPEC strain is the sum of its capacity for adherence, iron acquisition, toxin production and specific metabolite transport, is supported by our measurements of global gene expression patterns of UPEC during UTI in five women attending the University Health Service Clinic at the University of Michigan for the symptoms of cystitis. The rationale for the proposed work is that once we identify the most highly expressed virulence genes during UTI in humans, we can focus efforts on intervention and prevention directed toward these specific targets. We will test our central hypothesis and complete our objectives by carrying out two specific aims: 1) Determine the representative transcriptome for uropathogenic E. coli during urinary tract infection in humans; and 2) Determine the mechanism of pathogenesis for newly discovered virulence determinants upregulated in E. coli infecting women with urinary tract infection. The expected outcomes of conducting these aims will be a precise assessment of global gene expression and host-specific virulence genes upregulated during infection in women, but not during in vitro culture in urine or rich medium. The positive impact of these studies will be substantial. We will precisely quantify UPEC gene expression during infection of otherwise healthy women. We will determine the mechanisms of action of the newly identified virulence factors active during infection of the urinary tract by E. coli. We will also understand which virulence determinants are both present and expressed during uncomplicated human UTI, and the degree to which they are expressed. Understanding the virulence factors used by the bacterium to colonize the human urinary tract, avoid the immune response, and damage the host will open the door to preventing this public health scourge in women with recurrent UTI and those susceptible to their first UTI.