Mechanism of Bacterial Expulsion from Infected Bladder Cells.

受感染膀胱细胞排出细菌的机制。

• 批准号: 8544558
• 负责人: Soman N Abraham
• 金额: $ 20万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-30 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8544558
• 关键词: Accounting; Actins; Adaptor Signaling Protein; Antibiotics; Apical; Bacteria; Bacterial Infections; Binding; Biochemical; Bladder; Cell Survival; Cell membrane; Cells; Complex; Cyclic AMP; Defense Mechanisms; Development; Docking; Drug Delivery Systems; Elements; Epithelial Cells; Epithelium; Escherichia coli; Event; Exocytosis; Flushing; Housing; Human; Immune; Immune response; In Vitro; Infection; Knowledge; Lead; Maps; Mediating; Mediator of activation protein; Membrane Fusion; Membrane Microdomains; Molecular; Monomeric GTP-Binding Proteins; Pathway interactions; Process; Proteins; Recruitment Activity; Research; Role; SNAP receptor; Side; Signal Pathway; Signal Transduction; Structure; TLR4 gene; Therapeutic; Tubulin; Urinary tract; Urinary tract infection; Urine; Uropathogenic E. coli; Vesicle; Virulence; antimicrobial drug; base; combat; human SNAP23 protein; man; novel; novel strategies; prevent; protein complex; rab GTP-Binding Proteins; target SNARE proteins; toll-like receptor 4; trafficking; trait

Urinary tract infections (UTIs) account for the second most common bacterial infections in man. Most of these infections are caused by E.coli which have a distinct mechanism for entry into the highly impregnable superficial epithelium of the bladder. While investigating molecular aspects of how uropathogenic E.coli (UPEC) enter bladder epithelial cells (BECs), we observed that infected BECs have a powerful and largely overlooked capacity to exocytose most of the infecting UPEC without loss of cellular viability. These observations point to a powerful capacity of BECs to sense intracellular bacteria and initiate bacterial expulsion activities. Using biochemical and molecular approaches, we have identified a distinct mechanism in BECs that are capable of recognizing intracellular UPEC involving 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 cellular components in lipid raft compartments not traditionally associated in exocytic processes in the extrusion of bacteria through the plasma membrane. Studies to examine how these various signaling components and pathways integrate and achieve bacterial expulsion could provide valuable clues on how to therapeutically maximize bacterial expulsion mechanisms in the bladder. In this proposal, we plan to confirm and extend these observation in the following specific Aims: (i) Elucidate the mechanism by which TLR4 senses intravesicular E. coli in BECs. (ii) Investigate how exocyst complex and vesicular trafficking elements promote bacterial expulsion. (iii) Determine the contribution of SNARE complex to the membrane fusion and apical bacteria discharge. (iv) Identify components in cellular lipid raft fractions involved in bacterial expulsion.

尿路感染（UTI）是人类中第二大常见的细菌感染。大多数 这些感染是由大肠杆菌引起的，大肠杆菌具有独特的进入高度的机制 膀胱的浅表上皮不可固化。同时研究了如何 肝病大肠杆菌（UPEC）进入膀胱上皮细胞（BEC），我们观察到感染的BEC 具有强大的且在很大程度上被忽视的胞外染料的能力 细胞活力。这些观察表明，BEC有强大的能力感知细胞内 细菌并启动细菌驱逐活动。使用生化和分子方法，我们 已经确定了能够识别细胞内UPEC的BEC中的独特机制 涉及毫米生物监视分子，像受体（TLR）4。我们还确定了几个 细菌胞吐作用的关键介体，其中包括外囊复合物的成分A Rab GTPase，Rab11和Snare Complex。此外，我们在脂质中牵涉到细胞成分 传统上，筏室与细胞挤压中不相关的细菌通过 质膜。研究以检查这些各种信号成分和途径的研究 整合并实现细菌驱除可以提供有关如何治疗的宝贵线索 最大化膀胱中的细菌驱逐机制。在此提案中，我们计划确认和 在以下特定目的中扩展这些观察结果：（i）阐明TLR4的机制 在BEC中感觉到内部大肠杆菌。 （ii）研究外囊复合物和囊泡运输方式 元素促进细菌驱逐。 （iii）确定SNARE复合物对 膜融合和顶端细菌排出。 （iv）识别细胞脂质筏部分中的成分 参与细菌驱逐。