Pharmacological analysis of protein kinases responsible for chemotaxis of rat peritoneal neutrophils.

Several types of kinase inhibitors were used to investigate the possible signaling pathways leading to the chemotaxis of rat peritoneal neutrophils toward macrophage inflammatory protein-2, cytokine-induced neutrophil chemoattractant-1, and platelet-activating factor. The chemotaxis and shape changes induced by each of these chemoattractants were strongly inhibited by a tyrosine kinase inhibitor (herbimycin A) and protein kinase C inhibitors (H-7 (1-(5-isoquinolinesulphonyl)-2-methylpiperazine dihydrochloride) and calphostin C). The formation of phosphatidyl 3,4,5-triphosphate in chemoattractant-stimulated neutrophils was completely inhibited by 100 nM of wortmannin, an inhibitor of phosphatidylinositol 3-kinase, whereas the chemotaxis toward each of these chemoattractants was partially inhibited (50% inhibition). The mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK-1) inhibitor PD 98059 did not inhibit the neutrophil chemotaxis. These findings suggest that the activation of tyrosine kinase and protein kinase C strongly participates in neutrophil chemotaxis and that the activation of phosphatidylinositol 3-kinase is partially involved, but that the activation of mitogen-activated protein kinase is not involved in neutrophil chemotaxis. The cross-linking of the signaling pathways for chemotaxis toward each chemoattractant was also examined.