Immune mediated exocytosis of intravesicular UPEC from bladder cells

免疫介导的膀胱细胞囊内 UPEC 胞吐作用

基本信息

批准号：
8908009
负责人：
Soman N Abraham
金额：
$ 34万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-07 至 2018-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8908009
关键词：
Actins Adaptor Signaling Protein Antibiotics Apical Bacteria Bacterial Infections Binding Biochemical Bladder Caveolae Cell Culture Techniques Cell Survival Cell membrane Cells Complex Defense Mechanisms Detection Development Docking Drug Targeting Epithelial Cells Epithelium Escherichia coli Event Exocytosis Flushing Gastrointestinal tract structure Health Human Immune Immune response Immune system In Vitro Infection Infectious Agent Lead Lipopolysaccharides Mediating Mediator of activation protein Mining Molecular Monomeric GTP-Binding Proteins Mus Pathway interactions Pattern Recognition Play Process Proteins Proteome Recruitment Activity Reporting Research Role SNAP receptor Signal Transduction TLR4 gene Tubulin Urethra Urinary tract Urinary tract infection Urine Uropathogenic E. coli Vesicle Virulence apical membrane chemokine combat community-acquired UTI cytokine in vivo man microbial microbial colonization neutrophil novel novel strategies protein complex rab GTP-Binding Proteins research study response target SNARE proteins toll-like receptor 4 trafficking

项目摘要

DESCRIPTION (provided by applicant): Urinary tract infections (UTIs) continue to be the second most common bacterial infections in man. Most of these infections are caused by uropathogenic E. coli (UPEC) that gain access into bladder epithelial cells and persist intracellularly, where they are inaccessible to the immune system and also antibiotics. Remarkably, recent in vivo and in vitro studies on infected bladder epithelial cells have revealed that these cells have a powerful capacity to exocytose large proportions of infecting UPEC without loss of cell viability. These observations point to a powerful capacity of BECs to sense intracellular bacteria and initiate bacterial exocytosis. They also suggest that if the underlying mechanism were understood, it may be possible to utilize drugs targeting this pathway to boost this cellular defense mechanism. To date, using biochemical and molecular approaches, we have determined that a key molecule responsible for recognizing intracellular UPEC is the imunosurveillance molecule, Toll like Receptor (TLR) 4. We have also identified several key mediators of bacterial exocytosis, which include components of the exocyst complex a Rab GTPase, Rab11 and the SNARE complex. Additionally, we have implicated subcellular microdomains called caveolae in this exocytic process, in the extrusion of bacteria through the plasma membrane. Here we propose to examine how these various signaling components, pathways and subcellular microdomians integrate and achieve bacterial expulsion. We plan to confirm and extend this observation in the following specific aims: (i) Elucidate how intravesicular UPEC are detected by TLR4 in BECs. (ii) Determine how cellular machinery for vesicle trafficking mediates bacterial exocytosis. (iii) Investigate the role of SNARE proteins to docking and discharge of intravesicular UPEC (IV). Identify novel bacterial expulsion components using proteome mining approach.

描述（由申请人提供）：尿路感染（UTI）仍然是人类第二常见的细菌感染。这些感染大多数是由泌尿道致病性大肠杆菌（UPEC）引起的，它们可以进入膀胱上皮细胞并在细胞内持续存在，免疫系统和抗生素都无法接近它们。值得注意的是，最近对受感染膀胱上皮细胞的体内和体外研究表明，这些细胞具有强大的能力，可以在不丧失细胞活力的情况下胞吐大部分感染 UPEC。这些观察结果表明 BEC 具有感知细胞内细菌并启动细菌胞吐作用的强大能力。他们还建议，如果了解了潜在的机制，就有可能利用针对该途径的药物来增强这种细胞防御机制。迄今为止，利用生化和分子方法，我们已经确定负责识别细胞内 UPEC 的关键分子是免疫监视分子 Toll 样受体 (TLR) 4。我们还确定了细菌胞吐作用的几个关键介质，其中包括外囊复合体由 Rab GTPase、Rab11 和 SNARE 复合体组成。此外，我们还发现，在细菌通过质膜挤出的胞吐过程中，存在称为小窝的亚细胞微区。在这里，我们建议研究这些不同的信号成分、途径和亚细胞微结构如何整合并实现细菌排出。我们计划在以下具体目标中确认并扩展这一观察结果：（i）阐明 BEC 中 TLR4 如何检测囊泡内 UPEC。 (ii) 确定囊泡运输的细胞机制如何介导细菌胞吐作用。 (iii) 研究 SNARE 蛋白对囊泡内 UPEC 的对接和排出的作用 (IV)。使用蛋白质组挖掘方法识别新型细菌排出成分。