Involvement of phospholipase A2 in Pseudomonas aeruginosa-mediated PMN transepithelial migration
Involvement of phospholipase A2 in Pseudomonas aeruginosa-mediated PMN transepithelial migration
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DOI：
10.1152/ajplung.00390.2005
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发表时间：
2006-04-01
影响因子：
4.9
通讯作者：
McCormick, BA
中科院分区：
文献类型：
--
作者：
Hurley, BP;Williams, NL;McCormick, BA
肺炎和囊性纤维化期间呼吸道粘膜表面细菌感染引起的炎症会导致病理。炎症反应的一个主要后果是多形核细胞（PMN）募集到感染部位。为了到达气道，中性粒细胞必须通过多种细胞因子、趋化因子和粘附分子的作用穿过几个细胞和细胞外屏障。使用在 Transwell 过滤器和人 PMN 上生长的极化肺上皮细胞（A549 或 Calu-3）模型，我们发现铜绿假单胞菌诱导 PMN 跨肺上皮屏障迁移。该过程是由响应铜绿假单胞菌感染而产生的类花生酸肝素 A(3) (HXA(3)) 介导的。 HXA(3) 是一种由花生四烯酸 (AA) 代谢的中性粒细胞化学引诱剂。鉴于 AA 的释放被认为是生成类二十烷酸的限速步骤，我们研究了肺上皮细胞的铜绿假单胞菌感染是否导致游离 AA 的增加。 A549 或 Calu-3 单层的铜绿假单胞菌感染导致预标记肺上皮细胞释放的 [H-3]AA 显着增加。 PLA(2) 抑制剂 ONO-RS-082 和 ACA 以及二酰基甘油脂肪酶抑制剂可部分抑制这一现象。两种 PLA(2) 抑制剂均显着减少铜绿假单胞菌诱导的 PMN 迁移，而二酰基甘油脂肪酶抑制剂则没有效果。此外，我们观察到铜绿假单胞菌感染导致胞质PLA(2) (cPLA(2))磷酸化增加，这表明铜绿假单胞菌激活cPLA(2)产生游离AA的机制，该游离AA可能转化为HXA(3)，这是介导PMN迁移所必需的。
Inflammation resulting from bacterial infection of the respiratory mucosal surface during pneumonia and cystic fibrosis contributes to pathology. A major consequence of the inflammatory response is recruitment of polymorphonuclear cells (PMNs) to the infected site. To reach the airway, PMNs must travel through several cellular and extracellular barriers, via the actions of multiple cytokines, chemokines, and adhesion molecules. Using a model of polarized lung epithelial cells (A549 or Calu-3) grown on Transwell filters and human PMNs, we have shown that Pseudomonas aeruginosa induces PMN migration across lung epithelial barriers. The process is mediated by epithelial production of the eicosanoid hepoxilin A(3) (HXA(3)) in response to P. aeruginosa infection. HXA(3) is a PMN chemoattractant metabolized from arachidonic acid (AA). Given that release of AA is believed to be the rate-limiting step in generating eicosanoids, we investigated whether P. aeruginosa infection of lung epithelial cells resulted in an increase in free AA. P. aeruginosa infection of A549 or Calu-3 monolayers resulted in a significant increase in [H-3]AA released from prelabeled lung epithelial cells. This was partially inhibited by PLA(2) inhibitors ONO-RS-082 and ACA as well as an inhibitor of diacylglycerol lipase. Both PLA(2) inhibitors dramatically reduced P. aeruginosa-induced PMN transmigration, whereas the diacylglycerol lipase inhibitor had no effect. In addition, we observed that P. aeruginosa infection caused an increase in the phosphorylation of cytosolic PLA(2) ( cPLA(2)), suggesting a mechanism whereby P. aeruginosa activates cPLA(2) generating free AA that may be converted to HXA(3), which is required for mediating PMN transmigration.