PSEUDOMONAS PRODUCTS, OXYGEN RADICALS, AND LUNG INJURY

铜绿假单胞菌引起急性和慢性肺部感染 和其他部位导致明显的组织损伤。 形成反应性 氧物种，如超氧化物（O2）过氧化氢（H2 O2），和 羟自由基（OH）与组织损伤的关系日益密切 与一系列人类病理学有关。 OH，通过 铁（Fe）催化的O2和H2 O2的反应，是最具反应性的 氧自由基 我们实验室最近的工作表明， 由铜绿假单胞菌主动分泌的三种化合物可以单独或组合使用， 与中性粒细胞（PMN）衍生的O2/H2 O2结合，导致OH产生 以及随后的组织损伤。 这些产自铜绿假单胞菌的产品是： 绿脓菌螯铁蛋白，一种铜绿假单胞菌铁载体（Fe-螯合剂）， 雇用获得微环境FE，我们发现这是一个 有效OH催化剂;假弹性蛋白酶，aP.铜绿蛋白酶 我们发现它可以切割人类铁结合蛋白转铁蛋白， 能够催化OH生成的新型Fe螯合物;以及绿脓菌素aP 可以进行细胞介导的有氧氧化还原循环的铜绿产物 这导致O2和H2 O2的产生。 工作目标 提出的是调查潜在的具体目标已经有针对性 为了学习 目的1将评估铁-绿脓菌螯铁蛋白复合物， 铁绿脓菌螯铁蛋白（Fe-衍生的O2和H2 O2通过诱导OH的产生 靠近细胞膜。 目标2将确定氧化剂种类是什么 铁绿脓菌螯铁蛋白与O2/H2 O2相互作用过程中产生的 绿脓菌螯铁蛋白分子的特征有助于促进其 增强O2/H2 O2-细胞损伤，以及铜-绿脓菌螯铁蛋白是否增强 绿脓菌素通过催化OH产生介导的细胞毒性。 目标4将 确定转铁蛋白的假弹性蛋白酶切割是否也增强 O2/H2O介导的肺上皮和内皮细胞损伤 OH催化。 目标5将调查是否产生 氧化剂通过这些铜绿假单胞菌产物改变内皮细胞功能 a通过增加嗜中性粒细胞粘附进一步促进组织损伤 通过调节粘附配体的表达， 或血小板活化因子（PAF）的内皮细胞表面： 减少内皮细胞前列环素的产生：或增加 内皮细胞释放促炎细胞因子如TNF和 dIL-1。 因此，这些研究将探索新的和以前未探索的 铜绿假单胞菌衍生产品可能有助于 通过诱导产生有毒的氧物质而导致肺损伤。 等 这些信息最终可能会导致新的治疗方法的设计， 采取干预措施，降低艾滋病毒/艾滋病感染的发病率和死亡率， 肺和其他器官感染铜绿假单胞菌和相关细菌病原体。

Pseudomonas aeruginosa causes acute and chronic infections of the lung and other sites resulting in marked tissue damage. Formation of reactive oxygen species such as superoxide (O2) hydrogen peroxide (H2O2), and hydroxyl radical (OH) has been increasingly implicated in tissue injury associated with a wide array of human pathology. OH, generated via the iron (Fe)-catalyzed reaction of O2 and H2O2, is the most reactive of the oxygen free radical. Recent work from our laboratory has suggested that three compounds actively secreted by P. aeruginosa may alone, or in conjunction with neutrophil (PMN)-derived O2/H2O2, lead to OH generation and subsequent tissue injury. These P. aeruginosa-derived products are: pyochelin, a P. aeruginosa siderophore (Fe-chelator) which P. aeruginosa employs to acquire microenvironmental FE and which we found is an effective OH catalyst; pseudomonas elastase, aP. aeruginosa protease which we found cleaves the human Fe-binding protein transferrin to form new Fe chelates capable of catalyzing OH production; and pyocyanin aP aeruginosa product which can undergo cell-mediated aerobic redox cycling which results in the generation of O2 and H2O2. The goal of the work proposed is to investigate the potential specific aims have been targeted for study. Aim 1 will assess whether the iron-pyochelin complex, ferripyochelin (Fe-derived O2 and H2O2 by inducing the generation of OH near the cell membrane. Aim 2 will determine what oxidant species are generated during the interaction of Fe-pyochelin with O2/H2O2 what features of the pyochelin molecule serve to promote its ability to enhance O2/H2O2-cell injury, and whether a copper-pyochelin enhances pyocyanin-mediated cytotoxicity by catalyzing OH generation. Aim 4 will determine if pseudomonas elastase cleavage of transferrin also enhances O2/H2O mediated injury of pulmonary epithelial and endothelial cells through OH catalysis. Aim 5 will investigate whether the generation of oxidants by these P aeruginosa products alters endothelial cell function a as to further promote tissue injury by: increasing neutrophil adherence to endothelial cells by modulating the expression of adherence ligands or platelet activating factor (PAF) on the endothelial cell surface: decreasing endothelial cell prostacyclin production: or increasing endothelial cell release of pro-inflammatory cytokines such as TNF an dIL-1. Thus, these studies will explore novel and previously unexplored mechanisms whereby P. aeruginosa-derived products could contribute to lung injury by inducing the production of toxic oxygen species. Such information could eventually result in the design of new therapeutic intervention to decrease the morbidity and mortality of infections of the lung and other organs with P. aeruginosa and related bacterial pathogens.