The Pseudomonas aeruginosa protease CtpA and type 3 secretion

铜绿假单胞菌蛋白酶CtpA和3型分泌

• 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
• 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

 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（由申请方提供）：铜绿假单胞菌是一种常见的人类机会致病菌，可导致危及生命的疾病，包括急性肺炎、大多数囊性纤维化患者的长期肺部定植和严重伤口感染，尤其是住院患者和严重烧伤患者。大多数铜绿假单胞菌感染与宿主防御受损有关，这与生物体的常见环境发生一起，使其成为重症监护病房中脓毒症的第二大常见原因。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内在耐药性以及医院中偶尔爆发的多重耐药菌株。因此，迫切需要确定新的治疗攻击靶点。铜绿假单胞菌用于建立感染的最关键系统之一是被称为3型分泌系统的复杂蛋白质输出机器。我们现在已经发现，未表征的铜绿假单胞菌基因PA 5134/ctpA（周质C-末端加工蛋白酶）的失活阻止了正常的3型分泌系统活性，降低了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了它.然而，我们不明白为什么。该探索性项目建立在CtpA切割一种或多种细胞包膜蛋白是正常的3型分泌系统活性所需的中心假设上。为了验证这一假设，我们将：（1）确定CtpA的底物和（2）研究CtpA依赖性蛋白水解影响3型分泌的机制。这将提供关键的深入了解卵的CtpA和更好地了解它如何影响Pa毒力。这种对CtpA活性后果的洞察是非常重要的，特别是因为这种相对容易接近的周质蛋白最终可能被认为是治疗药物的有吸引力的靶标。