PHARMACOLOGICAL ANALYSIS OF PROTEIN-KINASES RESPONSIBLE FOR CHEMOTAXIS OF RAT PERITONEAL NEUTROPHILS

Several types of kinase inhibitors were used to investigate the possib le signaling pathways leading to the chemotaxis of rat peritoneal neut rophils toward macrophage inflammatory protein-2, cytokine-induced neu trophil chemoattractant-l, and platelet-activating factor. The chemota xis and shape changes induced by each of these chemoattractants were s trongly inhibited by a tyrosine kinase inhibitor (herbimycin A) and pr otein kinase C inhibitors (H-7 (1-(5-isoquinolinesulphonyl)-2-methylpi perazine dihydrochloride) and calphostin C). The formation of phosphat idyl 3,4,5-triphosphate in chemoattractant-stimulated neutrophils was completely inhibited by 100 nM of wortmannin, an inhibitor of phosphat idylinositol 3-kinase, whereas the chemotaxis toward each of these che moattractants was partially inhibited (50% inhibition). The mitogen-ac tivated protein kinase/extracellular signal-regulated kinase kinase (M EK-1) inhibitor PD 98059 did not inhibit the neutrophil chemotaxis. Th ese findings suggest that the activation of tyrosine kinase and protei n kinase C strongly participates in neutrophil chemotaxis and that the activation of phosphatidylinositol 3-kinase is partially involved, bu t that the activation of mitogen-activated protein kinase is not invol ved in neutrophil chemotaxis. The cross-linking of the signaling pathw ays for chemotaxis toward each chemoattractant was also examined. (C) 1998 Elsevier Science B.V. All rights reserved.