OmpR and acid regulation of Escherichia coli fim genes

描述(申请人提供)：尿路致病性大肠埃希菌(UPEC)是美国尿路感染的主要原因，每年导致数百万病例。在UPEC诱导的尿路感染中，附着上皮细胞是至关重要的第一步。1型菌毛介导了这种结合，动物研究表明这种菌毛类型在人类膀胱感染中起着关键作用。1型菌毛的表达受时相变化的影响，细胞可以在有毛和无毛状态之间切换。有9个FIM基因参与了1型菌毛的表达，包括编码结构亚基的FIMA基因和影响FIMB和FIME编码的相位变化的位点特异性重组酶。几个环境因素影响这些fim基因的调控，但对调节生活在人类尿路的UPEC中fim基因表达的环境线索知之甚少。由于UPEC每年导致许多尿路感染，这项拨款建议通过进行DNA酶足迹、PCRS、Western blots和报告分析来阐明FIMA、FIMB和FIME的表达，以回答OmpR和耐酸基因蛋白可能如何调控UPEC中1型Pilus的表达。此外，这项提案将首次使用报告系统检查UPEC细胞中这三个基因的调节情况，这些细胞接种到小鼠的尿路中。Fim基因是如何调控的将被揭开，这可能对未来的预防策略有用，这些策略利用饮食变化来改变人类尿路的内部环境，并防止UPEC结合。 本研究将有助于我们了解尿路致病性大肠埃希菌I型菌毛FIM基因的调控。通过了解fim基因是如何调控的，我们可能能够通过改变饮食或药物来治疗未来的尿路感染，这些药物会影响导致1型菌毛表达的调节级联反应。

DESCRIPTION (provided by applicant): Uropathogenic Escherichia coli (UPEC) are the leading cause of urinary tract infections in the United States, resulting in millions of cases each year. Attachment to epithelial cells is a vital first step in UPEC induced urinary tract infections. Type 1 pili mediate this binding, and animal studies have shown a critical role for this pilus type in human bladder infections. Expression of type 1 pili is affected by phase variation whereby cells can switch between piliated and nonpiliated states. Nine fim genes are involved in type 1 pilus expression, including the fimA gene that encodes the structural subunits and site-specific recombinases that affect phase variation encoded by fimB and fimE. Several environmental factors influence regulation of these fim genes, but little is known about the environmental cues regulating fim gene expression in UPEC living in the human urinary tract. Because UPEC cause many urinary tract infections each year, this grant proposes to answer how OmpR and acid tolerance gene proteins may be regulating type 1 pilus expression in UPEC by performing DNase footprinting, PCRs, Western blots, and reporter assays to elucidate fimA, fimB, and fimE expression. Moreover, this proposal will examine for the first time the regulation of these three genes in UPEC cells inoculated into murine urinary tracts using a reporter system. How the fim genes are regulated will be uncovered, which could be useful for future prevention strategies that use dietary changes to change the internal environment of the human urinary tract and prevent the UPEC from binding. This research will help us understand the regulation of type 1 pili fim genes in uropathogenic Escherichia coli growing in human urinary tracts. By understanding how the fim genes are regulated, we may be able to treat urinary tract infections in the future through dietary changes or drugs that affect the regulatory cascade that leads to type 1 pilus expression.