Mechanisms of Pseudomonas Resistance to Membrane Permeabilization by SP-A

假单胞菌对 SP-A 膜透化的抗性机制

• 批准号: 7790727
• 负责人: Gee W Lau
• 金额: $ 39.03万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7790727
• 关键词: A Mouse; Anabolism; Antibiotic Resistance; Bacteria; Binding; Biological Assay; Calcium; Carbohydrates; Cause of Death; Cell membrane; Cessation of life; Chelating Agents; Chemotaxis; Collectins; Data; Employee Strikes; Figs - dietary; Flagella; Goals; Human; Individual; Infection; Lead; Libraries; Life; Lipopolysaccharide Biosynthesis Pathway; Lipopolysaccharides; Lung; Measures; Mediating; Membrane; Microbe; Modification; Mutagenesis; Nosocomial Infections; Paralysed; Pathway interactions; Peptide Hydrolases; Permeability; Phosphotransferases; Pneumonia; Predisposition; Process; Proteins; Pseudomonas; Pseudomonas aeruginosa; Publishing; Pulmonary Surfactant-Associated Protein A; Pulmonary Surfactant-Associated Proteins; Pulmonary Surfactants; Pyruvate; Pyruvates; Relative (related person); Reporting; Resistance; Role; Sepsis; Testing; Transplantation; antimicrobial; antimicrobial peptide; comparative; cystic fibrosis patients; killings; macrophage; microbial; mutant; pathogen; public health relevance; pyochelin; salicylate; treatment strategy

DESCRIPTION (provided by applicant): Traditionally, the pulmonary surfactant protein-A (SP-A) is thought to opsonize and enhance the clearance of microbial pathogens. Recently, we have reported that SP-A also directly kills Pseudomonas aeruginosa (PA) in a macrophage-independent manner, by increasing the permeability of bacterial membranes. However, the mechanism by which SP-A disrupts PA cell membranes and its relative importance in lung defense are poorly defined. In addition, how microbes protect themselves against SP-A is unknown. Especially, we have shown that wild-type PA strain PA01 is resistant to membrane permeabilization by SP-A. Our long-term goal is to understand the antimicrobial mechanisms of SP-A, and to reveal how bacteria confer resistance/susceptibility to SP-A. The overall hypothesis to be tested is that PA pathways including flagellum, salicylate and pyochelin, and phosphoenol-pyruvate phosphotransferase, are important to resist membrane permeabilization by SP-A. Our hypothesis is supported by our published and preliminary data which show that PA mutant strains deficient in flagellum (flgE), deficient in salicylate and pyochelin biosynthesis (pchA), and defective in producing phosphoenol-pyruvate phosphotransferase (ptsP), are preferentially cleared in the SP-A+/+ mouse lungs, but survived in the SP-A-/- mouse lungs. Most strikingly, the flgE, pchA and ptsP mutant bacteria show significant increase in susceptibility to SP-A mediated membrane permeabilization, but not opsonization. We propose three aims to examine the mechanisms by which flagellum, PchA and PtsP pathways maintain LPS and cell membrane integrity, and regulate the bacterial processes that inactivate SP-A, to confer resistance to killing by SP-A-mediated membrane permeabilization and to killing by SP-A and antimicrobial peptides and proteins (AMPPs) whose functions that are either dependent or aided by SP-A. Aim 1 will determine the "offensive" strategies orchestrated by PA's flagellum, PchA and PtsP to confer resistance to SP-A-mediated membrane permeabilization. These offensive measures to be tested include the ability of PA to secrete proteases that degrade SP-A, and to secrete salicylate that strips Ca2+ associated with SP-A, which is required for the activity of SP-A. Aim 2 will determine the "defensive" strategies orchestrated by PA's flagellum, salicylate/pyochelin and phosphoenol-pyruvate phosphotransferase to confer resistance to SP-A-mediated membrane permeabilization. The defensive measures to be determined include increased LPS biosynthesis and modification, and chemotaxis evasion. Aim 3 will examine the hypothesis that during the initial interactions, SP-A preemptively "paralyzes" PA, allowing other AMPPs to act synergistically or additively to kill the bacteria. We will use "checker board" assays to determine the roles of flagellum, PchA and PtsP pathways against individual, synergistic and additive killing by individual AMPP alone, different combinations of AMMPs, and AMMPs with SP-A. Completion of the proposed aims will enhance our understanding of the antimicrobial mechanisms of the SP-A and lead to new treatment strategies for pneumonias. PUBLIC HEALTH RELEVANCE: Pseudomonas aeruginosa is one of the most common causes of nosocomial infections in humans, lung infections in cystic fibrosis patients, and a primary cause of death and sepsis in immuno-compromised individuals. The continuous emergence of antibiotic resistant P. aeruginosa, which can lead to denial for lung transplant, infection and death, emphasize the urgent need to explore alternative strategies to manage P. aeruginosa infections. Enhance understanding of the antimicrobial mechanisms of the Surfactant Protein A, and the mechanisms by which P. aeruginosa confers resistance/susceptibility to Surfactant Protein A may lead to new treatment strategies for life-threatening pneumonias.

描述（由申请人提供）：传统上，认为肺表面活性剂蛋白A（SP-A）被认为可以调整并增强微生物病原体的清除率。最近，我们报告说，SP-A还通过增加细菌膜的渗透性来直接以巨噬细胞独立的方式杀死铜绿假单胞菌（PA）。然而，SP-A破坏PA细胞膜及其在肺防御中的相对重要性的机制的定义很差。此外，微生物如何保护自己免受SP-A的侵害是未知的。特别是，我们已经表明，野生型PA菌株PA01对SP-A的膜透化具有抗性。我们的长期目标是了解SP-A的抗菌机制，并揭示细菌如何赋予SP-A的耐药性/敏感性。要测试的总体假设是PA途径在内，包括鞭毛，水杨酸酯和毕胆素以及磷酸烯醇 - 丙酮酸磷酸磷酸转移酶，对于通过SP-A抵抗膜通透性很重要。 Our hypothesis is supported by our published and preliminary data which show that PA mutant strains deficient in flagellum (flgE), deficient in salicylate and pyochelin biosynthesis (pchA), and defective in producing phosphoenol-pyruvate phosphotransferase (ptsP), are preferentially cleared in the SP-A+/+ mouse lungs, but survived in the SP-A - / - 小鼠肺。最引人注目的是，FLGE，PCHA和PTSP突变细菌显示出SP-A介导的膜通透性的敏感性显着增加，但没有调理。 We propose three aims to examine the mechanisms by which flagellum, PchA and PtsP pathways maintain LPS and cell membrane integrity, and regulate the bacterial processes that inactivate SP-A, to confer resistance to killing by SP-A-mediated membrane permeabilization and to killing by SP-A and antimicrobial peptides and proteins (AMPPs) whose functions that are either dependent or aided by sp-a。 AIM 1将确定PA的Flagellum，PCHA和PTSP精心策划的“进攻”策略，以赋予SP-A介导的膜通透性的抵抗力。这些要测试的进攻措施包括PA分泌降解SP-A的蛋白酶的能力，并分泌与SP-A相关的ca2+的水杨酸盐，这是SP-A活性所必需的。 AIM 2将确定PA的鞭毛，水杨酸酯/毕胆素和磷酸烯醇 - 丙酮酸磷酸转移酶策划的“防御”策略，以赋予SP-A介导的膜透气化的耐药性。要确定的防御措施包括增加的LPS生物合成和修饰以及趋化性逃避。 AIM 3将研究以下假设：在最初的相互作用中，SP-A先发制于“瘫痪” PA，允许其他AMPP协同或附加的作用以杀死细菌。我们将使用“ Checker板”测定法来确定单独的AMPP，不同的AMPS的不同组合和SP-A的AMMP，以确定鞭毛，PCHA和PTSP途径的作用。拟议的目标的完成将增强我们对SP-A的抗菌机制的理解，并导致针对肺炎的新治疗策略。公共卫生相关性：铜绿假单胞菌是人类中医院感染，囊性纤维化患者的肺部感染以及免疫增强个体中死亡和败血症的最常见原因之一。抗生素抗生素铜绿假单胞菌的连续出现，这可能导致肺部移植，感染和死亡的拒绝，这强调了迫切需要探索管理铜绿假单胞菌感染的替代策略。增强对表面活性剂蛋白A的抗菌机制的了解，以及铜绿假单胞菌赋予表面活性剂蛋白A的耐药性/易感性的机制，可能会导致危及生命的肺炎的新治疗策略。