Deciphering the source and consequences of Nur77 expression during E. coli rUTI in mice

摘要 复发性尿路感染(RUTI)是一个昂贵的临床问题，影响着全球数百万妇女和 导致全球抗生素耐药性的上升。多条证据表明，阴道中的细菌 会影响对尿路感染的敏感性。例如，患有阴道微生物失调的妇女称为细菌性阴道病(BV)。 患尿路感染的风险增加。几种阴道细菌--包括与BV相关的阴道加德纳氏菌 (G.V.)-从直接从膀胱通过针吸或经尿道收集的尿液中分离出来 导尿术。尽管培养条件通常不足以检测到它，但G.V.的存在。在尿液中也是 与鲁蒂有流行病学上的联系。我们已经开发了新的小鼠模型来确定阴道的影响 细菌对泌尿系感染的新视角--检验暂时性膀胱暴露于阴道细菌的想法 例如G.V.对引起尿路感染的主要原因--大肠杆菌(E.C.)的致病作用。我们之前 证明了G.V.可引起小鼠膀胱上皮细胞的凋亡和脱落。当老鼠藏匿的时候 E.C.潜在的细胞内膀胱库。来自之前的实验感染，G.V.引发了E.C.的出现。 而Ruti的致死率是单独接触车辆的小鼠的4倍。这些数据表明，暴露在膀胱中 致通用汽车。可能是女性发生鲁蒂的诱因。 在细胞和分子水平上了解G.V.触发角质剥落和Ruti，我们已经检查了 对G.V.的转录反应。使用批量RNA测序。这一分析表明，通用汽车。 诱导孤儿核受体Nur77(也称为Nr4a1)的表达。Nur77是公认的 在其他组织的疾病中，它在细胞凋亡和炎症反应中的作用，但在尿路中的作用是 很大程度上没有人研究。我们使用Nur77-/-小鼠的初步数据表明，G.V.需要Nur77。触发E.C. Ruti在我们的小鼠模型中。在这篇聚焦R03的文章中，我们试图回答关于 Nur77对G.V.诱导的E.C.的作用Ruti：在G.V.之后，膀胱中的哪些细胞类型表达Nur77。 曝光？(目标1)，以及哪些宿主对G.V.暴露-脱落或炎性细胞因子 生产-是由Nur77调节的吗？(目标2)。我们建议的实验建立在我们的初步数据和 利用现有的Nur77基因敲除和报告小鼠以及我们在详细描述膀胱反应方面的经验 微生物暴露。这些研究的成功完成将提供重要的机械洞察 通用汽车。触发E.C.并将生成关键数据，以便在此基础上构建未来的R01提案。

ABSTRACT Recurrent urinary tract infection (rUTI) is a costly clinical problem that affects millions of women worldwide and contributes to the global rise in antibiotic resistance. Multiple lines of evidence indicate that bacteria in the vagina can affect susceptibility to UTI. For example, women with the vaginal dysbiosis called bacterial vaginosis (BV) are at increased risk of UTI. Several vaginal bacteria—including the BV-associated species Gardnerella vaginalis (G.v.)—have been isolated from urine collected directly from the bladder by needle aspiration or transurethral catheterization. Although culture conditions are not often poised to detect it, the presence of G.v. in urine is also epidemiologically linked with rUTI. We have developed new mouse models to define the impact of vaginal bacteria on UTI from a new perspective—testing the idea that transient bladder exposures to vaginal bacteria such as G.v. influence the pathogenesis of Escherichia coli (E.c.), the leading cause of UTI. We previously demonstrated that G.v. triggers apoptosis and exfoliation of the bladder epithelium in mice. When mice harbored latent intracellular bladder reservoirs of E.c. from a prior experimental infection, G.v. triggered emergence of E.c. and rUTI at a rate 4-fold higher than mice exposed to vehicle alone. These data indicate that bladder exposures to G.v. could represent a trigger of rUTI in women. To understand at the cellular and molecular level how G.v. triggers exfoliation and rUTI, we have examined the transcriptional response to G.v. in the bladder using bulk RNA sequencing. This analysis revealed that G.v. induced the expression of the orphan nuclear receptor Nur77 (also called Nr4a1). Nur77 is well-recognized for its role in apoptosis and in inflammatory responses in diseases in other tissues, but its role in the urinary tract is largely unstudied. Our preliminary data using Nur77-/- mice indicate that Nur77 is required for G.v. to trigger E.c. rUTI in our mouse model. In this focused R03, we seek to answer two fundamental questions regarding the contribution of Nur77 to G.v.-induced E.c. rUTI: Which cell types in the bladder express Nur77 following G.v. exposure? (Aim 1), and Which host responses to G.v. exposure—exfoliation or inflammatory cytokine production—are mediated by Nur77? (Aim 2). Our proposed experiments build upon our preliminary data and leverage available Nur77 knockout and reporter mice and our experience in detailing bladder responses to microbial exposures. Successful completion of these studies will provide important mechanistic insights into how G.v. triggers E.c. rUTI and will generate key data on which to build a future R01 proposal.