TYPE 1 FIMBRIAE AND URINARY TRACT INFECTIONS

1 型菌毛和尿路感染

• 批准号: 6475504
• 负责人: DAVID L HASTY
• 金额: $ 19.56万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-12-01 至 2003-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6475504
• 关键词: Escherichia coli; bacteria infection mechanism; bacterial genetics; bactericidal immunity; cytokine; enzyme linked immunosorbent assay; gene expression; histopathology; host organism interaction; immunocytochemistry; laboratory mouse; leukocyte activation /transformation; pilus; polymerase chain reaction; urinary tract infection; virulence

DESCRIPTION (Adapted from the Applicant's Abstract): Type I fimbriae are important for the urovirulence of E. coli, because they mediate adhesion, stimulate a mucosal immune response and mediate interactions with phagocytes. Experimental studies indicate the importance of type 1 fimbriae, but previous epidemiological studies found no correlation, perhaps because of the virtual ubiquity of the fim (type 1) gene cluster. Allelic variants of the gene for the FimH adhesin subunit that significantly alter the receptor-binding phenotype of E. coli have recently been discovered. Their distribution suggests that certain phenotypes offer a selective advantage in the urinary tract. This hypothesis is supported by preliminary animal studies. The effects of the expression of different fimH allelic variants on the ability of E. coli to colonize the mouse urinary tract will be studied. Isogenic E. coli strains will be inoculated into mouse bladders and infection studied by quantitative cultures and histopathology. We will identify the murine uroepithelial cell receptor(s) for E. coli expressing different fimH alleles. Preliminary studies lead us to focus on the asymmetrical unit membrane plaques (AUMs) of transitional epithelium and their constituent proteins, the uroplakins. In vitro and in vivo adhesion and adhesion inhibition assays (using uroplakin-specific antibodies) will be performed to confirm whether these molecules are the type 1 receptors. We will study the recruitment of leukocytes into the urinary tract mucosa of infected mice. The adhesion, ingestion and calling of E. coli by human and mouse peripheral blood PMN will be quantified and extracellular and intracellular release of oxygen metabolites will be measured. We will characterize the induction of cytokine production in urinary tract mucosa of mice infected with a recombinant E. coli strain exhibiting an M\H type 1 fimbrial phenotype typical of UTI isolates. When the basic responses have been characterized, we will determine whether qualitatively or quantitatively different responses are elicited by E. coli expressing different "fimH alleles. Production of inflammatory and regulatory cytokines will be measured by ELISAs and/or message will be measured by. RT-PCR. Cellular source(s) of cytokines will be determined by immunocytochemistry. The long-term goal of this research is to understand the role of type 1 fimbriae in the pathogenesis of UTIs to eventually enhance procedures for treatment or prevention.

描述（改编自申请人的摘要）：I 型菌毛是 对于大肠杆菌的尿毒力很重要，因为它们介导 粘附、刺激粘膜免疫反应并介导相互作用 与吞噬细胞。实验研究表明类型的重要性 1 菌毛，但之前的流行病学研究没有发现相关性， 也许是因为 fim（1 型）基因几乎无处不在 簇。 FimH 粘附素亚基基因的等位基因变体 显着改变大肠杆菌的受体结合表型 最近被发现。它们的分布表明某些 表型在泌尿道中提供了选择性优势。这 假设得到初步动物研究的支持。的影响 不同 fimH 等位基因变体的表达对大肠杆菌能力的影响。 将研究大肠杆菌定植于小鼠泌尿道。同基因E. 大肠杆菌菌株将被接种到小鼠膀胱并发生感染 通过定量培养和组织病理学进行研究。我们将确定 表达大肠杆菌的鼠尿上皮细胞受体 不同的 fimH 等位基因。初步研究使我们关注 移行上皮的不对称单位膜斑块（AUM）和 它们的组成蛋白是尿斑蛋白。体外和体内 粘附和粘附抑制测定（使用尿斑蛋白特异性 抗体）将被执行以确认这些分子是否是 1型受体。我们将研究白细胞招募到 受感染小鼠的尿路粘膜。粘附、摄入和 通过人类和小鼠外周血 PMN 来检测大肠杆菌 定量细胞外和细胞内氧的释放 将测量代谢物。我们将描述归纳 感染小鼠尿道粘膜的细胞因子产生 表现出 M\H 1 型菌毛表型的重组大肠杆菌菌株 典型的尿路感染分离株。当基本反应已经 特征，我们将确定是定性还是定量 表达不同“fimH”的大肠杆菌会引发不同的反应 等位基因。炎症和调节性细胞因子的产生将 通过 ELISA 测量和/或将通过信息测量。逆转录聚合酶链反应。蜂窝网络 细胞因子的来源将通过免疫细胞化学来确定。这 这项研究的长期目标是了解 1 型的作用 尿路感染发病机制中的菌毛最终增强程序 用于治疗或预防。