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

• 批准号: 8668381
• 负责人: Soman N Abraham
• 金额: $ 33.69万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 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/8668381
• 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; 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; public health relevance; rab GTP-Binding Proteins; research study; response; target SNARE proteins; toll-like receptor 4; trafficking

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（UTIs）仍然是人类第二大常见的细菌感染。大肠杆菌（UPEC）进入膀胱上皮细胞并持续存在于细胞内，在那里它们无法进入免疫系统和抗生素。值得注意的是，最近对感染的膀胱上皮细胞的体内和体外研究已经揭示，这些细胞具有强大的胞吐大比例的感染UPEC而不损失细胞活力的能力。这些观察结果表明BEC具有强大的能力来感知细胞内细菌并启动细菌胞吐作用。他们还表明，如果了解了潜在的机制，就有可能利用靶向这一途径的药物来增强这种细胞防御机制。迄今为止，使用生物化学和分子方法，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，其中包括胞吐复合物Rab GT3、Rab 11和SNARE复合物的组分。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，我们建议检查这些不同的信号成分，途径和亚细胞microdomians整合，并实现细菌驱逐。我们计划在以下具体目标中确认和扩展该观察结果：（i）阐明BEC中TLR4如何检测囊内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蛋白在囊泡内UPEC对接和放电中的作用（IV）。利用蛋白质组挖掘方法鉴定新的细菌排出组分。