Robinson Alexander J, Kashanin Dmitry, O'Dowd Frank, Williams Vivienne, Walsh Garry M
School of Medicine, University of Aberdeen, Aberdeen, Scotland, UK.
J Leukoc Biol. 2008 Jun;83(6):1522-9. doi: 10.1189/jlb.1007717. Epub 2008 Mar 10.
Montelukast (MLK) is a cysteinyl leukotriene receptor-1 (cysLT(1)R) antagonist with inhibitory effects on eosinophils, key proinflammatory cells in asthma. We assessed the effect of MLK on resting and GM-CSF-stimulated eosinophil adhesion to recombinant human (rh)VCAM-1 at different flow rates using our novel microflow system. At 1 or 2 dyn cm(-2), shear-stress unstimulated eosinophils tethered immediately to rhVCAM-1, "rolled" along part of the channel until they tethered, or rolled without tethering. At flow rates greater than 2 dyn cm(-2), adherent eosinophils began to be displaced from rhVCAM-1. MLK (10 nM and 100 nM) gave partial ( approximately 40%) but significant (P<0.05) inhibition of unstimulated eosinophil adhesion to rhVCAM-1 at 1 or 2 dyn cm(-2) shear stress. Once adhered, unstimulated eosinophils did not exhibit morphological changes, and GM-CSF-stimulated eosinophil adhesion under flow was characterized by greater cell flattening with significant (P<0.05) inhibition of adherent cell numbers by 100 nM MLK observed. This effect appeared specific for MLK, as the analog (E)-3-[[[3-[2-(7-chloro-2-quinolinyl)ethenyl]phenyl]-[[3-dimethylamino)-3-oxopropyl]thio]methyl]thio]-propanoic acid, sodium salt, had no significant effect on eosinophil adhesion to VCAM-1. The possibility that LTC(4), released from unstimulated or GM-CSF-treated eosinophils, contributed to their adhesion to VCAM-1 was excluded as the LT biosynthesis inhibitor 3-[1-(p-Chlorobenzyl)-5-(isopropyl)-3-t-butylthioindol-2-yl]-2,2-dimethylpropanoic acid had no inhibitory effect, and exogenously added LTC(4) did not enhance eosinophil adhesion. In contrast, LTD(4) enhanced eosinophil adhesion to VCAM-1, an effect blocked by MLK (10 and 100 nM). These findings demonstrate that MLK-mediated inhibition of unstimulated and GM-CSF-stimulated eosinophil adhesion to VCAM-1 under shear-stress conditions appears independent of cysLT(1)R antagonism.
孟鲁司特（MLK）是一种半胱氨酰白三烯受体-1（cysLT(1)R）拮抗剂，对嗜酸性粒细胞具有抑制作用，嗜酸性粒细胞是哮喘中的关键促炎细胞。我们使用新型微流系统评估了MLK在不同流速下对静息和GM-CSF刺激的嗜酸性粒细胞与重组人（rh）VCAM-1黏附的影响。在1或2达因/平方厘米时，剪切应力未刺激的嗜酸性粒细胞立即与rhVCAM-1结合，沿着通道的一部分“滚动”，直到它们结合，或者不结合而滚动。在流速大于2达因/平方厘米时，黏附的嗜酸性粒细胞开始从rhVCAM-1上被冲走。MLK（10 nM和100 nM）在1或2达因/平方厘米的剪切应力下对未刺激的嗜酸性粒细胞与rhVCAM-1的黏附产生部分（约40%）但显著（P<0.05）的抑制作用。一旦黏附，未刺激的嗜酸性粒细胞没有表现出形态变化，并且在流动条件下GM-CSF刺激的嗜酸性粒细胞黏附的特征是细胞更加扁平，观察到100 nM MLK对黏附细胞数量有显著（P<0.05）的抑制作用。这种作用似乎对MLK具有特异性，因为类似物（E）-3-[[[3-[2-(7-氯-2-喹啉基)乙烯基]苯基]-[[3-二甲基氨基)-3-氧代丙基]硫代]甲基]硫代]-丙酸，钠盐，对嗜酸性粒细胞与VCAM-1的黏附没有显著影响。未刺激或GM-CSF处理的嗜酸性粒细胞释放的LTC(4)促成其与VCAM-1黏附的可能性被排除，因为白三烯生物合成抑制剂3-[1-(对氯苄基)-5-(异丙基)-3-叔丁基硫代吲哚-2-基]-2,2-二甲基丙酸没有抑制作用，并且外源性添加的LTC(4)没有增强嗜酸性粒细胞的黏附。相反，LTD(4)增强了嗜酸性粒细胞与VCAM-1的黏附，这种作用被MLK（10和100 nM）阻断。这些发现表明，在剪切应力条件下，MLK介导的对未刺激和GM-CSF刺激的嗜酸性粒细胞与VCAM-1黏附的抑制作用似乎独立于cysLT(1)R拮抗作用。
