Novel virulence and exoenzyme regulators

新型毒力和外酶调节剂

• 批准号: 8070413
• 负责人: ROBERT M SHANKS
• 金额: $ 36.16万
• 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/8070413
• 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(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，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。粘质葡萄球菌还导致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，其结果与显著的发病率和死亡率相关。目前还缺乏使用同基因突变菌株研究粘质链球菌基因如何导致眼部感染的研究。这项研究的广泛的长期目标是预防这种细菌引起的角膜感染后的视力丧失。更好地了解粘质链球菌毒力因子的调控机制，将为减少这些因子的表达导致的组织损伤和角膜混浊提供一种新的方法。这种关于特定途径的新知识可以用于定制设计新型抗感染药物。随着细菌继续对现有类别的抗生素产生抗药性，建立新的治疗靶点变得越来越重要。我们要检验的总体特异性假设是，转录因子Eepr/S是一个关键的毒力因子，它控制着组织损伤金属蛋白酶的表达和溶血素的活性。我们的初步数据支持粘质链球菌中的EEPR/S突变严重减弱了粘质链球菌在活体角膜炎眼部模型中的致病作用。我们的中心假说将通过实现以下目标来验证：目的1.验证粘质链球菌体外细胞毒和体内致病所必需的EEPR/S、四种金属蛋白酶和ShlA溶血素的假说。目的2.验证EEPR和EPS调控金属蛋白酶和溶血素基因转录的假说，以及EEPR/S与其他转录因子(C反应蛋白、HexS和PigP)处于一条调控途径。 与公共卫生相关：细菌引起的眼部感染在美国以及国外的发达国家和发展中国家都是一个常见且代价高昂的问题。超过10万美国人因危险细菌引起的角膜感染(角膜炎)而丧失视力。粘质沙雷氏菌是严重的、有时是致命的医院获得性感染和损害视力的社区获得性角膜感染的常见原因。粘质葡萄球菌促进危及视力的角膜感染的基因到目前为止还没有研究过。这项研究旨在确定粘质链球菌是如何成功感染和损害角膜的。具体地说，我们将评估分泌型蛋白酶、一种形成孔洞的溶血素和一种新发现的基因调控系统的作用。这些问题的答案将有助于创造治疗粘质葡萄球菌眼部感染和减少感染相关视力丧失的新药。