Bacterial invasion of of eukaryotic tissues

细菌侵入真核组织

• 批准号: 6678369
• 负责人: DENNIS J KOPECKO
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6678369
• 关键词: bacteria infection mechanism; bacterial cytopathogenic effect; bacterial genetics; biological signal transduction; cell component structure /function; confocal scanning microscopy; cytoskeleton; enteric bacteria; eukaryote; fluorescence microscopy; gastrointestinal epithelium; gastrointestinal infection; gram negative bacteria; host organism interaction; human tissue; messenger RNA; molecular cloning; molecular pathology; nucleic acid quantitation /detection; receptor; receptor binding; tissue /cell culture; transmission electron microscopy; video microscopy; virulence

Summary: Many bacterial pathogens of the intestinal tract have as an early and necessary step in initiation of disease the ability to penetrate gut epithelial cells. My lab's work in the early 1980's established that Shigella's genetic machinery to trigger invasion is encoded on a large virulence-associated plasmid. More recent studies have shown that the invasion ability of other enteric bacteria is chromosomally encoded. This project is aimed at understanding the prokaryotic and eukaryotic requirements for bacterial internalization, with the ultimate aim being a thorough molecular definition of the events involved in bacterial invasion of eukaryotic tissues. Current experimental approaches involve the use of assays measuring bacterial entry into cultured lines of human epithelial cells of various tissue origins. Biochemical inhibitors of prokaryotic structure/function or of eukaryotic cell processes are employed in these tissue culture invasion assays to examine the requirements for bacterial uptake. Direct visualization of bacterial entry is measured via transmission electron microscopy,video microscopy,fluorescent microscopy, and confocal microscopy. In addition to the approaches described above, genetic techniques are employed to clone the responsible bacterial genes. Eukaryotic receptors for bacterial ligands and specific eukaryotic cell responses to bacterial invasion are measured via inhibitor competition assays, ligand binding assays, and mRNA analyses of infected eukaryotic cells. The information gained from each of these approaches is integrated to provide a mechanistic understanding of bacterial entry for each pathway studied. Recent progress has revealed that Campylobacter jejuni invasion is dependent upon host microtubules but not microfilaments. Apparent signalling by the approaching bacterium triggers the host cell to extend a microtubule-based, fingerlike projection. C. jejuni interacts with a host receptor located in membrane caveolae at the tip of this membrane extension. This bacterial-host "ligand -receptor" interaction activates a signal transduction cascade that releases Ca++ from intracellular stores and activates PI-3 kinase, calmodulin, and protein kinase C, which are required for C. jejuni internalization. The entering bacterium within an endosome moves via dynein and microtubules to the perinuclear region over 4 hrs.

摘要：许多肠道细菌病原体具有穿透肠道上皮细胞的能力，这是疾病发生的早期和必要步骤。我的实验室在20世纪80年代早期的工作确定了志贺氏菌触发入侵的遗传机制是在一个大的毒力相关质粒上编码的。最近的研究表明，其他肠道细菌的入侵能力是由染色体编码的。