Characterization of vacuole escape in Shigella infection

志贺氏菌感染中液泡逃逸的特征

基本信息

批准号：
9976031
负责人：
HERVE F AGAISSE
金额：
$ 23.75万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-02-01 至 2022-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9976031
关键词：
Actins Acyltransferase Africa Agreement Animal Model Asia Bacteria Biochemical Bioinformatics Cell Line Cell membrane Cell physiology Cells Cessation of life Chemicals Colon Confocal Microscopy Country Cysteine Cytoskeleton Cytosol Defect Disease Distal Dose Epithelial Cells Foundations Genetic HT29 Cells Hemorrhagic colitis Human Human Volunteers Income Individual Infant Infection Inflammation Intestinal Mucosa Intestines Invaded Latin America Mass Spectrum Analysis Measures Mediating Membrane Modeling Modification Molecular Monomeric GTP-Binding Proteins Mucous Membrane Mutation Needles Oral Oryctolagus cuniculus Outcome Pathogenesis Pathology Pathway interactions Prevention Preventive Intervention Process Proteins Research Proposals Resolution Role Route Sanitation Shigella Infections Shigella flexneri Site Supporting Cell System Testing Therapeutic Intervention Time Travel Type III Secretion System Pathway Vacuole base cell motility cellular imaging design diarrheal disease enteric pathogen genetic approach high risk human model human pathogen imaging approach in vivo inhibitor/antagonist innovation insight low income country microbial mutant neonatal infection nonhuman primate pathogen polymerization recruit uptake

项目摘要

The intracellular pathogen Shigella flexneri is the causative agent of bacillary dysentery in humans. In low- income countries, poor sanitation is responsible for approximately 270 million cases of shigellosis annually, with at least 250,000 of these resulting in death. In high-income countries, shigellosis is typically associated with travel to high-risk regions (Latin America, Asia and Africa). The disease is characterized by severe bloody diarrhea and dramatic destruction of the colonic mucosa. S. flexneri is transmitted via the fecal-oral route and is extremely contagious, with a rate of attack above 90% with an infectious dose as low as 100-1000 bacteria per individual, as determined in human volunteer studies. S. flexneri is an intracellular pathogen that invades epithelial cells in the human colon. The bacteria trigger their own entry by injecting bacterial effector proteins through their type 3 secretion system (T3SS), leading to bacterial uptake into primary cellular vacuoles. The pathogen promptly escapes from primary vacuoles to gain access to the cytosolic compartment. In the cytosol, bacteria recruit components of the actin cytoskeleton and actin polymerization at the bacterial pole propel the pathogen throughout the cell. As motile bacteria reach cell-cell contacts, they form membrane protrusions that project into adjacent cells. The resolution of the formed protrusions leads to formation of double-membrane vacuoles (DMVs) in adjacent cells, from which the pathogens escape, thereby achieving cell-to-cell spread. The importance of this dissemination process in S. flexneri pathogenesis has been initially established through studies conducted in non-human primates or in human volunteers and recently demonstrated by our group in an infant rabbit model of bacillary dysentery. Although actin-based motility is now fairly well understood, the mechanisms supporting cell-to-cell spread are unclear. Our group has previously shown the importance of the T3SS in bacterial dissemination. Moreover, we have recently identified the T3SS effector protein IcsB as a critical determinant of DMV escape during cell-to-cell spread. Here we propose to explore how IcsB contribute to DMV escape in epithelial cells (Aim1) and how IcsB-mediated DMV escape contributes to pathogenesis in vivo (Aim2).

细胞内病原体志贺氏菌Flexneri是人类细菌痢疾的病因。在低 - 收入国家，卫生条件不佳，每年大约有2.7亿例志核病病例其中至少有25万导致死亡。在高收入国家，智格病通常是相关的前往高风险地区（拉丁美洲，亚洲和非洲）。该疾病的特征是严重的血腥结肠粘膜的腹泻和戏剧性破坏。 S. flexneri是通过粪便途径传输的，具有传染性，攻击速率超过90％，感染剂量低至100-1000个细菌每个人，如人类志愿者研究中所确定的。 S. flexneri是一种侵入的细胞内病原体人类结肠中的上皮细胞。细菌通过注入细菌效应蛋白来触发自己的进入通过其3型分泌系统（T3S），导致细菌摄取到原代细胞液泡中。这病原体迅速逃离原发性液泡以进入胞质室。在细胞质中，细菌募集肌动蛋白细胞骨架和肌动蛋白聚合在细菌极推进的成分整个细胞中的病原体。当运动细菌达到细胞细胞接触时，它们会形成膜突起投射到相邻的细胞中。形成的突起的分辨率导致形成双膜相邻细胞中的液泡（DMV），从中散发出病原体，从而实现细胞间扩散。这这种传播过程在S. flexneri发病机理中的重要性最初是通过在非人类灵长类动物或人类志愿者中进行的研究，最近由我们的小组在杆菌痢疾的婴儿兔模型。尽管基于肌动蛋白的运动现在已经相当理解了，但支持细胞间扩散的机制尚不清楚。我们的小组以前已经表明了细菌传播中的T3SS。此外，我们最近将T3SS效应蛋白ICSB确定为一种在细胞到细胞扩散期间，DMV逃逸的关键决定因素。在这里，我们建议探索ICSB如何贡献在上皮细胞中DMV逃脱（AIM1），以及ICSB介导的DMV逃逸如何有助于发病机理 Vivo（AIM2）。