Dept of Medicine, M6076, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL 60637, USA.
Eur Respir J. 2010 Feb;35(2):402-9. doi: 10.1183/09031936.00009309. Epub 2009 Aug 13.
We examined the functional role and mechanisms by which activation of cysteinyl leukotriene-1 receptor (cysLT(1)R) regulates beta(2)-integrin adhesion to intercellular adhesion molecule (ICAM)-1 in human polymorphonuclear leukocytes (PMNs) in vitro. Human peripheral blood PMNs and eosinophils were isolated separately from the same mildly atopic donors. Surface expression of cysLT(1)R was identified both in PMNs and in eosinophils by immunofluorescence analysis. Total cysLT(1)R protein was substantially greater in eosinophils than in PMNs as determined by Western blot analysis. However, leukotriene D(4) (LTD(4)) upregulated beta(2)-integrin adhesion of PMNs to ICAM-1 with high efficacy in a time- and concentration-dependent manner. Upregulated beta(2)-integrin adhesion of PMNs was related temporally and quantitatively to phosphorylation of 85-kDa cytosolic group IVa phospholipase A2 (gIVaPLA2). Augmented LTD(4)-induced adhesion was blocked significantly by montelukast, a cysLT(1)R antagonist. Trifluoromethylketone (a gIVaPLA2 inhibitor) blocked beta(2)-integrin adhesion caused by LTD(4) activation, as did anti-CD18 monoclonal antibody directed against beta(2)-integrin on the PMN surface. Our data demonstrate that LTD(4) causes phosphorylation of gIVaPLA2 and upregulation of beta(2)-integrin adhesion to ICAM-1 or ICAM-1 surrogate through cysLT(1)R activation. Activation of gIVaPLA2 is a critical step through which beta(2)-integrin adhesion is upregulated by the cysLT(1)R expressed on the surface membrane of human PMN.
我们研究了半胱氨酰白三烯 1 型受体（cysLT1R）激活在体外调节人嗜中性粒细胞（PMN）β2-整联蛋白与细胞间黏附分子（ICAM）-1黏附中的功能作用和机制。人类外周血 PMN 和嗜酸性粒细胞分别从同一轻度过敏供体中分离。通过免疫荧光分析鉴定 PMN 和嗜酸性粒细胞中 cysLT1R 的表面表达。Western blot 分析表明，总 cysLT1R 蛋白在嗜酸性粒细胞中明显多于 PMN。然而，白三烯 D4（LTD4）以时间和浓度依赖的方式高效地上调 PMN 的β2-整联蛋白与 ICAM-1 的黏附。PMNs 的β2-整联蛋白黏附的上调与 85kDa 胞质 IVa 磷脂酶 A2（gIVaPLA2）的磷酸化在时间上和数量上相关。cysLT1R 拮抗剂孟鲁司特显著阻断了 LTD4 诱导的黏附。三氟甲基酮（gIVaPLA2 抑制剂）阻断了 LTD4 激活引起的β2-整联蛋白黏附，抗 PMN 表面上的β2-整联蛋白 CD18 单克隆抗体也阻断了 LTD4 激活引起的β2-整联蛋白黏附。我们的数据表明，LTD4 导致 gIVaPLA2 的磷酸化和通过 cysLT1R 激活导致β2-整联蛋白与 ICAM-1 或 ICAM-1 替代物的黏附上调。gIVaPLA2 的激活是 PMN 表面膜上表达的 cysLT1R 通过上调β2-整联蛋白黏附的关键步骤。
