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)是人类第二常见的细菌感染。大部分 这些感染是由大肠杆菌引起的，它有一种独特的进入高度 牢不可破的膀胱表面上皮。在研究分子方面如何 尿路致病性大肠杆菌(UPEC)进入膀胱上皮细胞(BECs)，我们观察到感染的BECs 有一种强大的、但在很大程度上被忽视的能力，可以无损失地排出大部分感染UPEC 细胞的生存能力。这些观察结果表明，BEC具有强大的细胞内感知能力 细菌和启动细菌排出活动。使用生化和分子方法，我们 已经在BEC中发现了一种能够识别细胞内UPEC的独特机制 涉及免疫监视分子，Toll样受体(TLR)4。我们还发现了几个 细菌胞吐作用的关键介质，包括胞囊复合体a-Rab的成分 GTPase、Rab11和SNARE复合体。此外，我们还发现脂肪中含有细胞成分。 传统上不与胞外过程相关的浮筏隔间 质膜。研究这些不同的信号成分和通路是如何 整合和实现细菌排出可为如何治疗提供有价值线索 最大限度地利用膀胱中的细菌排出机制。在这份提案中，我们计划确认和 将这些观察结果扩展到以下具体目的：(I)阐明TLR4 在BECs中感觉囊泡内的大肠杆菌。(2)调查外囊如何复杂化和囊泡运输 元素促进细菌的排出。(3)确定圈套复合体对 膜融合和根尖细菌排出。(四)鉴定细胞脂筏组分中的成分 与细菌排泄有关。