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（由申请人提供）：细菌性角膜炎是一个昂贵且全球性的问题，导致视力丧失和失明，而Marcescens是社区获得的革兰氏阴性细菌角膜炎的领先者。马克斯霉菌还引起许多医院获得的感染，包括肺炎，心内膜炎，菌血症和尿路感染，通常对当前的抗生素具有抗药性，并且其结果与显着的发病率和死亡率有关。缺乏研究研究链球菌基因如何使用等源性突变菌株对眼部感染有何贡献。这项研究的广泛长期目标是防止在这种生物引起的角膜感染后视力丧失。对Marcescens毒力因子的机制有更好的了解将允许采用一种新的方法来减少组织损伤和角膜无情，这是由于这些因素的表达而导致的。有关特定途径的新知识可用于定制设计新颖的反感染物。随着细菌继续对现有抗生素类型的抗性，建立新的治疗靶标变得越来越重要。我们要测试的总体特定假设是转录因子EEPR/s是控制组织破坏金属蛋白酶和溶血素活性的关键毒力因子。我们的初步数据支持，在马甲中，EEPR/S的突变严重减弱了在体内角质炎的体内眼部模型中Marcescens的发病机理。我们的中心假设将通过实现以下目的来检验：目标1。检验假设，即EEPR/S，四个金属蛋白酶和SHLA血解素在体内的体外和眼部发病机中需要S. marcescenss。marcescenss. shla hemolysin。 AIM 2。检验EEPR和EEPS调节金属蛋白酶和溶血素基因的转录的假设，并且EEPR/S处于具有其他转录因子（CRP，HEXS和PIGP）的调节途径中。 公共卫生相关性：细菌引起的眼部感染在美国以及国外发展和发展中的国家都是一个普遍且昂贵的问题。由于危险细菌引起的角膜感染（角膜炎），超过100,000名美国人因视力丧失而生活。细菌铜质铜质经常引起严重，有时是致命的医院感染，视力损害了社区获得的角膜感染。迄今为止尚未研究促进威胁性角膜感染的铜霉基因。这项研究旨在确定S. marcescens如何成功感染和破坏角膜。具体而言，我们将评估分泌蛋白酶，形成孔的血溶素和新发现的遗传调节系统的作用。这些问题的答案将允许创建新药物来治疗Marcescens的眼部感染并减少与感染相关的视力丧失。