INTERACTION OF THE PSEUDOMONAS-AERUGINOSA SECRETORY PRODUCTS PYOCYANIN AND PYOCHELIN GENERATES HYDROXYL RADICAL AND CAUSES SYNERGISTIC DAMAGE TO ENDOTHELIAL-CELLS - IMPLICATIONS FOR PSEUDOMONAS-ASSOCIATED TISSUE-INJURY
INTERACTION OF THE PSEUDOMONAS-AERUGINOSA SECRETORY PRODUCTS PYOCYANIN AND PYOCHELIN GENERATES HYDROXYL RADICAL AND CAUSES SYNERGISTIC DAMAGE TO ENDOTHELIAL-CELLS - IMPLICATIONS FOR PSEUDOMONAS-ASSOCIATED TISSUE-INJURY
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DOI：
10.1172/jci116104
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发表时间：
1992-12-01
影响因子：
15.9
通讯作者：
COX, CD
中科院分区：
文献类型：
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作者：
BRITIGAN, BE;ROEDER, TL;COX, CD
绿青素是铜绿假单胞菌的一种分泌产物，能够在有氧条件下进行氧化还原循环，产生超氧化物和过氧化氢。利用自旋捕捉技术结合电子顺磁共振波谱(EPR)，在NADH或猪内皮细胞有氧还原绿色素的过程中检测到超氧化物歧化。没有检测到羟基自由基形成的证据。草酸铬消除了内皮细胞暴露于绿青素所产生的超氧化物衍生的自旋加合物的EPR谱，表明超氧化物在内皮细胞质膜附近形成。我们以前已经报道过，铜绿假单胞菌铁质载体上的铁通过Haber-Weiss反应催化超氧化物和过氧化氢生成羟基自由基。在本研究中，当NADH和绿色素在铁蛋白存在下反应时，检测到了羟基自由基形成的自旋陷阱证据。同样，内皮细胞暴露于绿青素和铁蛋白也会导致羟基自由基的产生，这似乎发生在接近细胞表面的地方。根据Cr-51释放的评估，单独用绿青素或铁蛋白处理的内皮细胞表现出轻微的损伤。然而，内皮细胞暴露在绿蛋白和绿青素的组合中，导致55%的特异性铬-51释放。无铁的褐蛋白没有引起细胞损伤，过氧化氢酶或二甲基硫脲的存在可减轻细胞的损伤。这些数据表明，铜绿假单胞菌的分泌产物绿青素和绿球蛋白可能通过产生羟基自由基协同作用，损害假单胞菌感染部位的局部组织。
Pyocyanin, a secretory product of Pseudomonas aeruginosa, has the capacity to undergo redox cycling under aerobic conditions with resulting generation of superoxide and hydrogen peroxide. By using spin trapping techniques in conjunction with electron paramagnetic resonance spectrometry (EPR), superoxide was detected during the aerobic reduction of pyocyanin by NADH or porcine endothelial cells. No evidence of hydroxyl radical formation was detected. Chromium oxalate eliminated the EPR spectrum of the superoxide-derived spin adduct resulting from endothelial cell exposure to pyocyanin, suggesting superoxide formation close to the endothelial cell plasma membrane. We have previously reported that iron bound to the P. aeruginosa siderophore pyochelin (ferripyochelin) catalyzes the formation of hydroxyl free radical from superoxide and hydrogen peroxide via the Haber-Weiss reaction. In the present study, spin trap evidence of hydroxyl radical formation was detected when NADH and pyocyanin were allowed to react in the presence of ferripyochelin. Similarly, endothelial cell exposure to pyocyanin and ferripyochelin also resulted in hydroxyl radical production which appeared to occur in close proximity to the cell surface. As assessed by Cr-51 release, endothelial cells which were treated with pyocyanin or ferripyochelin alone demonstrated minimal injury. However, endothelial cell exposure to the combination of pyochelin and pyocyanin resulted in 55% specific Cr-51 release. Injury was not observed with the substitution of iron-free pyochelin and was diminished by the presence of catalase or dimethyl thiourea. These data suggest the possibility that the P. aeruginosa secretory products pyocyanin and pyochelin may act synergistically via the generation of hydroxyl radical to damage local tissues at sites of pseudomonas infection.