PSEUDOMONAS PRODUCTS, OXYGEN RADICALS, AND LUNG INJURY

铜绿假单胞菌引起急性和慢性肺部感染 和其他部位造成明显的组织损伤。反应性的形成 氧物种，如超氧化物(O2)、过氧化氢(H2O2)，以及 羟基自由基(OH)与组织损伤的关系日益密切 与广泛的人类病理有关。哦，通过 铁(Fe)催化的O2和H2O2的反应是最活跃的 氧自由基。我们实验室最近的研究表明 铜绿假单胞菌主动分泌的三种化合物可能单独或在 与中性粒细胞(PMN)产生的O2/H2O2结合，导致OH的产生 以及随后的组织损伤。这些铜绿假单胞菌衍生产品包括： 铜绿假单胞菌的铁载体(铁络合剂) 雇佣来获得微环境FE，我们发现这是一种 有效的羟基催化剂；假单胞菌弹性蛋白酶，AP。铜绿假单胞菌蛋白酶 我们发现它能裂解人铁结合蛋白转铁蛋白形成 能够催化产生羟基的新型铁络合物；以及绿色素AP 可进行细胞介导的有氧氧化还原循环的铜绿假单胞菌 这会导致O2和H2O2的产生。这项工作的目标 建议是为了调查已经有针对性的潜在具体目标 为了学习。目标1将评估铁-绿球蛋白复合体， 铁蛋白(铁衍生的O2和通过诱导产生OH而产生的过氧化氢 靠近细胞膜。目标2将确定氧化剂的种类 铁-褐球蛋白与O2/H2O2相互作用产生什么 品红分子的特性有助于提高它的能力 增强O_2/H_2O_2-细胞损伤，以及一种铜绿蛋白是否增强 绿青素通过催化羟基生成而介导的细胞毒性。目标4将 测定假单胞菌弹性蛋白酶对转铁蛋白的裂解作用是否也增强 O2/H2O介导的肺上皮细胞和内皮细胞损伤 通过OH催化。目标5将调查是否产生了 这些铜绿假单胞菌产物的氧化剂改变内皮细胞功能 A AS通过增加中性粒细胞黏附进一步促进组织损伤 通过调节黏附配体的表达对内皮细胞的作用 或内皮细胞表面的血小板激活因子(PAF)： 内皮细胞前列环素产生减少或增加 内皮细胞释放促炎细胞因子如肿瘤坏死因子 DIL-1。因此，这些研究将探索新的和以前未曾探索过的东西 铜绿假单胞菌衍生产品可促进 通过诱导有毒氧物种的产生而造成的肺损伤。是这样的 信息最终可能导致设计新的治疗方法 采取干预措施降低人群感染的发病率和死亡率 肺部和其他器官有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.