Human type II phospholipase A2-induced Mac-1 expression on human neutrophils.
To investigate the effect of type II phospholipase A2 (PLA2-II) on neutrophil function, we assessed the Mac-1 (CD11b/CD18) expression on human neutrophils by flow cytometry after incubation of the cells with human PLA2-II. PLA2-II at a concentration of 10 microg/mL increased the Mac-1 expression by 150% compared with unstimulated cells at 30 min and after. Under these conditions PLA2-II increased the exocytosis from secretory vesicles but not from azurophilic, specific, or gelatinase granules. The results suggest that PLA2-II induces translocation of Mac-1 from the secretory vesicles to the plasma membrane. The Mac-1 induction mediated by PLA2-II was inhibited by an anti-PLA2-II antibody, which was able to inhibit the catalytic activity. However, the Mac-1 induction by PLA2-II was not inhibited by a 5-lipoxygenase, cyclooxygenase inhibitor, or a platelet-activating factor antagonist. Thus, we examined the effects of fatty acids and lysophospholipids on Mac-1 expression. Only arachidonic acid induced Mac-1 expression. These results imply that PLA2-II induces Mac-1 expression on neutrophils via production of arachidonic acid.
Takasaki
J
J
Molecular Medicine Research Laboratory III, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., Tsukuba, Ibaraki, Japan.
Kawauchi
Y
Y
Yasunaga
T
T
Masuho
Y
Y
D000098:Acetophenones / Q000494:pharmacology; D000906:Antibodies / Q000494:pharmacology; D016718:Arachidonic Acid / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D005089:Exocytosis / Q000187:drug effects; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology; D054501:Group II Phospholipases A2; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism / Q000494:pharmacology; D016177:Macrophage-1 Antigen / Q000096:biosynthesis*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism*; D010741:Phospholipases A / Q000037:antagonists & inhibitors / Q000276:immunology / Q000494:pharmacology*; D054467:Phospholipases A2
D000098:Acetophenones; D000906:Antibodies; D005227:Fatty Acids; D008246:Lysophospholipids; D016177:Macrophage-1 Antigen; D016718:Arachidonic Acid; D010741:Phospholipases A; D054501:Group II Phospholipases A2; D054467:Phospholipases A2; C006821:4-bromophenacyl bromide; D002118:Calcium