The role of prophage life cycle in Stx production and disease due to EHEC

原噬菌体生命周期在 Stx 产生和 EHEC 引起的疾病中的作用

基本信息

批准号：
8416401
负责人：
KATHRYN A. EATON
金额：
$ 23.33万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-02-01 至 2014-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8416401
关键词：
Affect Animal Disease Models Bacteria Bacteriophages Biohazardous Substance Categories Centers for Disease Control and Prevention (U.S.)Child Colitis Complication Cultured Cells Cytolysis Development Diagnosis Dialysis procedure Disease Elements Escherichia coli EHEC Excision Fluid Therapy Gene Expression Genes Genetic Recombination Genome Goals Hemolytic-Uremic Syndrome Human In Vitro Infection Institutes Kidney Failure Kidney Transplantation Life Cycle Stages Measures Mediating Mutation National Institute of Allergy and Infectious Disease Phase Production Prophage Inductions Prophages Recovery Role Severities Shiga Toxin Shiga-Like Toxin II Supportive care Survivors System Time Variant Virulence base disability foodborne in vivo late disease onset mortality mouse model pathogen pathogenic bacteria prevent programs therapy development

项目摘要

DESCRIPTION (provided by applicant): Enterohemorrhagic Escherichia coli (EHEC) are food-borne bacterial pathogens that cause severe and occasionally fatal hemorrhagic colitis (HC). Young children are disproportionately affected by severe manifestations of disease, and may develop hemolytic-uremic syndrome (HUS), a rapidly progressive and sometimes fatal form of renal failure. HUS is an uncommon complication of disease due to EHEC, but its importance is amplified by its severity, tendency to affect young children, and the absence of any specific treatment or preventative measure. EHEC is listed as a CDC/NIAID category B biohazard agent. When HUS does occur, it is often after recovery from the diarrheic phase. Intensive fluid therapy instituted at the time of EHEC diagnosis has shown to be somewhat protective against HUS development, but therapy remains non-specific and the factors that determine whether or not HUS develops are incompletely understood. Both HC and HUS are caused by Shiga toxins (Stx), which in most EHEC strains are encoded on prophages and released following prophage induction. Control of Stx production and release is encoded within the phage genome, but the factors that control Stx production and release in vivo are poorly characterized. We hypothesize that suppressing induction and/or phage functions during the diarrheic phase will suppress Stx in vivo and synergize with supportive therapy, to ameliorate or prevent the onset of HUS. The goal of this proposal is to identify phage functions that contribute to Stx production in vivo, and therefore could represent targets for Stx suppression in vivo. We will use the ; phage-based recombination system, recombineering, to generate mutations in specific phage genes, and evaluate the role of the encoded functions in Stx production and release both in vitro and in vivo. The two specific aims are: Aim 1: Determine the extent to which phage-mediated lysis, excision, circularization, and replication control Stx2 production and release. Aim 2: Determine which of the phage functions identified in aim 1 contribute to virulence in a well- characterized Shiga toxin-dependent animal model of disease.

描述（由申请人提供）：肠肠肠癌大肠杆菌（EHEC）是食源性细菌病原体，会导致严重且偶尔致命的出血性结肠炎（HC）。幼儿受到严重疾病表现的影响不成比例，并且可能发展出溶血性尿毒症综合征（HUS），这是一种迅速进行的肾衰竭形式。 HUS是由于EHEC引起的疾病并发症的罕见并发症，但其重要性因其严重程度，影响幼儿的趋势以及缺乏任何特定治疗或预防措施而扩大。 EHEC被列为CDC/NIAID类别B Biohazard代理。当确实发生HUS时，通常是在从腹泻阶段恢复之后。在EHEC诊断时进行的强化液体疗法已证明对HUS发育有些保护，但疗法仍然非特异性，而确定HUS开发的因素是否不完全理解。 HC和HUS都是由Shiga毒素（STX）引起的，在大多数EHEC菌株中，该菌株在预言中编码并在预言诱导后释放。控制STX生产和释放的控制是在噬菌体基因组中编码的，但是控制STX生产和体内释放的因素的特征很差。我们假设在腹泻阶段抑制诱导和/或噬菌体功能将在体内抑制STX并通过支持性治疗协同作用，以改善或防止HUS的发作。该建议的目的是确定在体内有助于STX产生的噬菌体功能，因此可以代表体内STX抑制的靶标。我们将使用;基于噬菌体的重组系统，重新组合，以在特定的噬菌体基因中产生突变，并评估编码功能在STX生产中的作用，并在体外和体内释放。两个具体的目的是：目标1：确定噬菌体介导的裂解，切除，循环和复制控制STX2的产生和释放的程度。 AIM 2：确定AIM 1中确定的噬菌体功能的哪些噬菌体功能有助于疾病的疾病依赖性动物模型中的特征性志贺毒素依赖性动物。