The Pseudomonas aeruginosa protease CtpA and type 3 secretion

铜绿假单胞菌蛋白酶CtpA和3型分泌

基本信息

批准号：
8995635
负责人：
ANDREW J. DARWIN
金额：
$ 21.19万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-02-01 至 2018-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8995635
关键词：
Acute Acute Pneumonia Affect Alanine Animal Model Antibiotic Resistance Antibiotics Attenuated Bacteria Burn injury C-terminal Cell Signaling Process Chronic Cleaved cell Communicable Diseases Complement Complex Data Defect Disease Disease Outbreaks Drug Targeting Genes Health Hospitals Host Defense Human Immune system In Vitro Infection Intensive Care Units Investigation Learning Life Lung Mammalian Cell Mass Spectrum Analysis Motivation Multi-Drug Resistance Organism Patients Peptide Hydrolases Periplasmic Proteins Pharmaceutical Preparations Phenotype Process Protein Export Pathway Proteins Proteolysis Pseudomonas aeruginosa Pseudomonas serine proteinase Research Resistance Resolution Sepsis Serine Staging System Testing Virulence Virulence Factors Work Wound Infection attenuation cell envelope cystic fibrosis patients cytotoxicity design env Gene Products in vivo insight mouse model mutant new therapeutic target novel novel therapeutic intervention pathogen periplasm prevent protein complex research study resistant strain targeted treatment

项目摘要

DESCRIPTION (provided by applicant): The bacterium Pseudomonas aeruginosa is a common opportunistic human pathogen that causes life- threatening illnesses, including acute pneumonia, long-term lung colonization in most cystic fibrosis patients, and severe wound infections, especially in hospitalized patients and those with severe burns. Most P. aeruginosa infections are associated with compromised host defense and this, together with the common environmental occurrence of the organism, makes it the second most common cause of sepsis in the intensive care unit. The resolution of P. aeruginosa disease is challenging, in part because of its intrinsic resistance to antibiotics as well as occasional outbreaks of multi-drug-resistant strains in hospitals. Therefore, there is an urgent need to identify new targets for therapeutic attack. One of the most critical systems that P. aeruginosa uses to establish an infection is a complex protein export machine known as a type 3 secretion system. We have now discovered that inactivation of the uncharacterized P. aeruginosa gene PA5134/ctpA (periplasmic C- terminal processing protease) prevents normal type 3 secretion system activity, reduces the cytotoxicity of P. aeruginosa towards cultured mammalian cells, and severely attenuates it in an animal model of acute infection. However, we do not understand why. This exploratory project is founded on the central hypothesis that the cleavage of one or more cell envelope proteins by CtpA is required for normal type 3 secretion system activity. To test this hypothesis we will: (1) Identify substrates of CtpA and (2) Investigate the mechanism by which CtpA-dependent proteolysis affects type 3 secretion. This will provide critical insight into the roe of CtpA and a better understanding of how it affects Pa virulence. Such insight into the consequences of CtpA activity is very important, especially because this relatively accessible periplasmic protein could eventually be considered as an attractive target for therapeutic drugs that inactivate it.

描述（由申请人提供）：铜绿假单胞菌是一种常见的机会性人类病原体，可引起危及生命的威胁，包括急性肺炎、大多数囊性纤维化患者的长期肺部定植以及严重的伤口感染，尤其是住院患者和大多数铜绿假单胞菌感染与宿主防御受损有关，加上该生物体在环境中的常见情况，使其成为脓毒症的第二个最常见原因。铜绿假单胞菌疾病的解决具有挑战性，部分原因是其对抗生素的固有耐药性以及医院中偶尔爆发的多重耐药菌株，因此迫切需要识别新的耐药菌株。铜绿假单胞菌用来建立感染的最关键系统之一是一种复杂的蛋白质输出机器，称为 3 型分泌系统，我们现在发现未表征的铜绿假单胞菌基因失活。 PA5134/ctpA（周质 C 末端加工蛋白酶）可阻止正常的 3 型分泌系统活性，降低铜绿假单胞菌对培养的哺乳动物细胞的细胞毒性，并在急性感染的动物模型中严重减弱其细胞毒性。但是，我们不明白为什么。该探索性项目的核心假设是，CtpA 裂解一种或多种细胞包膜蛋白是正常 3 型分泌系统活性所必需的。为了检验这一假设，我们将：(1) 识别 CtpA 的底物，以及 (2) 研究 CtpA 依赖性蛋白水解影响 3 型分泌的机制，这将为了解 CtpA 的作用提供重要见解，并更好地了解它如何影响 Pa。对 CtpA 活性后果的深入了解非常重要，特别是因为这种相对容易获得的周质蛋白最终可能被认为是使其失活的治疗药物的有吸引力的靶点。