Novel virulence and exoenzyme regulators

新型毒力和外酶调节剂

• 批准号: 8260347
• 负责人: ROBERT M SHANKS
• 金额: $ 36.12万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8260347
• 关键词: Address; American; Anti-Infective Agents; Antibiotic Resistance; Antibiotics; Attenuated; Bacteremia; Bacteria; Blindness; Cell model; Cells; Clinical; Communities; Cornea; Custom; DNA-Protein Interaction; Data; Developed Countries; Developing Countries; Endocarditis; Epithelial Cells; Eye Infections; Figs - dietary; Foundations; Future; Gene Targeting; Genes; Genetic; Genetic Transcription; Hemolysin; In Vitro; Infection; Keratitis; Knock-out; Knowledge; Laboratories; Lead; Life; Metalloproteases; Methods; Modeling; Morbidity - disease rate; Mutate; Mutation; Nosocomial Infections; Organism; Oryctolagus cuniculus; Outcome; Pathogenesis; Pathogenicity; Pathway interactions; Peptide Hydrolases; Pharmaceutical Preparations; Pneumonia; Production; Proteins; RNA; Regulation; Regulator Genes; Regulatory Pathway; Research; Resistance; Resistance development; Reverse Transcriptase Polymerase Chain Reaction; Role; Serratia marcescens; System; Testing; Tissues; Transcriptional Regulation; United States; Urinary tract infection; Virulence; Virulence Factors; Vision; corneal epithelium; cytotoxicity; design; exoenzyme; in vivo; mortality; mutant; new therapeutic target; novel; novel strategies; pathogen; prevent; public health relevance; transcription factor

DESCRIPTION (provided by applicant): Bacterial keratitis is a costly and global problem that results in vision loss and blindness, and Serratia marcescens is a leading agent of community-acquired Gram-negative bacterial keratitis. S. marcescens also causes many hospital acquired infections including pneumonia, endocarditis, bacteremia and urinary tract infections that are commonly resistant to current antibiotics and whose outcomes are associated with significant morbidity and mortality. There is a lack of studies that investigate how S. marcescens genes contribute to ocular infections using isogenic mutant strains. The broad long-term objective of this research is to prevent vision loss following corneal infections caused by this organism. A better understanding of the mechanisms by S. marcescens virulence factors are regulated will allow for a novel approach to reduce tissue damage and corneal opacification that results from the expression of these factors. This new knowledge about specific pathways can be used to custom design novel anti-infectives. Establishing new therapeutic targets is becoming ever more important as bacteria continue to develop resistance to existing classes of antibiotics. Our overall specific hypothesis to be tested is that the transcription factor EepR/S is a critical virulence factor that controls expression of tissue damaging metalloprotease and hemolysin activities. Our preliminary data supports that the mutation of EepR/S in S. marcescens severely attenuates the pathogenesis of S. marcescens in an in vivo ocular model of keratitis. Our central hypothesis will be tested by accomplishing the following aims: Aim 1. Test the hypothesis that EepR/S, four metalloproteases and the ShlA hemolysin are required for S. marcescens cytotoxicity in vitro and ocular pathogenesis in vivo. Aim 2. Test the hypothesis that EepR and EepS regulate transcription of metalloprotease and hemolysin genes, and that EepR/S is in a regulatory pathway with other transcription factors (crp, hexS and pigP). PUBLIC HEALTH RELEVANCE: Ocular infections caused by bacteria are a common and costly problem in the United States and in both developed and developing nations abroad. Over 100,000 Americans live with vision loss due to corneal infections (keratitis) caused by dangerous bacteria. The bacterium Serratia marcescens is a frequent cause of serious and sometimes fatal hospital acquired infections and vision impairing community-acquired corneal infections. S. marcescens genes that facilitate vision-threatening corneal infections have not been studied to date. This study is designed to determine how S. marcescens is able to successfully infect and damage the cornea. Specifically, we will evaluate the role of secreted proteases, a pore-forming hemolysin, and a newly discovered genetic regulatory system. The answers to these questions will allow for the creation of new drugs to treat S. marcescens ocular infections and reduce infection-associated vision loss.

描述（由申请人提供）：细菌性角膜炎是一个代价高昂的全球性问题，会导致视力丧失和失明，而粘质沙雷氏菌是社区获得性革兰氏阴性细菌性角膜炎的主要病原体。粘质沙门氏菌还会引起许多医院获得性感染，包括肺炎、心内膜炎、菌血症和尿路感染，这些感染通常对当前的抗生素具有耐药性，其结果与显着的发病率和死亡率相关。目前还缺乏研究粘质链球菌基因如何利用同基因突变株导致眼部感染的研究。这项研究的广泛长期目标是防止这种微生物引起的角膜感染后视力丧失。更好地了解粘质沙门氏菌毒力因子的调节机制将有助于找到一种新方法来减少这些因子表达导致的组织损伤和角膜混浊。关于特定途径的新知识可用于定制设计新型抗感染药物。随着细菌不断对现有类别的抗生素产生耐药性，建立新的治疗靶点变得越来越重要。我们要测试的总体具体假设是转录因子 EepR/S 是控制组织损伤性金属蛋白酶和溶血素活性表达的关键毒力因子。我们的初步数据支持，粘质链球菌中 EepR/S 的突变严重减弱了角膜炎体内眼模型中粘质链球菌的发病机制。我们的中心假设将通过实现以下目标进行检验： 目标 1. 检验以下假设：EepR/S、四种金属蛋白酶和 ShlA 溶血素是粘质沙门氏菌体外细胞毒性和体内眼部发病机制所必需的。目标 2. 检验以下假设：EepR 和 EepS 调节金属蛋白酶和溶血素基因的转录，以及 EepR/S 与其他转录因子（crp、hexS 和 pigP）处于调节途径中。 公共卫生相关性：细菌引起的眼部感染是美国以及国外发达国家和发展中国家的一个常见且代价高昂的问题。超过 100,000 名美国人因危险细菌引起的角膜感染（角膜炎）而视力丧失。粘质沙雷氏菌是严重甚至有时致命的医院获得性感染和视力受损的社区获得性角膜感染的常见原因。迄今为止，尚未研究促进威胁视力的角膜感染的粘质沙门氏菌基因。本研究旨在确定粘质沙门氏菌如何成功感染和损伤角膜。具体来说，我们将评估分泌蛋白酶、成孔溶血素和新发现的基因调控系统的作用。这些问题的答案将有助于开发新药来治疗粘质沙门氏菌眼部感染并减少感染相关的视力丧失。