Receptor-coupled signal transduction in human polymorphonuclear neutrophils: effects of a novel inhibitor of phospholipase C-dependent processes on cell responsiveness.
1-[6-[[17 beta-3-Methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]- 1H-pyrrole-2,5-dione (U-73122), an inhibitor of phospholipase C (PLC)-dependent processes in human platelets, was found to be a potent inhibitor of human polymorphonuclear neutrophil (PMN) activation by structurally unrelated receptor-specific agonists. U-73122 caused a time- and concentration-dependent (0.1-1 microM) inhibition of myeloperoxidase and vitamin B12-binding protein release from PMNs exposed to N-formyl-methionyl-leucyl-phenylalanine, recombinant human C5a, leukotriene B4 and platelet-activating factor. Activation of the respiratory burst, as measured by superoxide anion production, in PMNs stimulated with these agonists was also suppressed by U-73122. These data suggested that U-73122 inhibited a component of signal transduction that was common to the mechanisms of action of these stimuli. Production of inositol 1,4,5-trisphosphate and 1,2-diacylglycerol and the rise in the cytosolic free calcium concentration, which are early postreceptor events in PMN activation, were all suppressed in U-73122-treated PMNs stimulated with the agonists. These signal transduction events require activation of PLC. Receptor-coupled activation of PLC in membranes isolated from PMNs was potently inhibited by U-73122. U-73122, however, had no direct effect on PMN protein kinase C activity. 1-[6-[[17 beta-3-Methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl] -2,5- pyrrolidine-dione (U-73343), a close analog of U-73122 that does not suppress PLC activity, did not inhibit receptor-specific agonist-induced PMN responsiveness. U-73122, therefore, is a novel reagent that is useful in investigating PLC function in receptor-mediated PMN activation.
Smith
R J
RJ
Department of Hypersensitivity Diseases Research, Upjohn Company, Kalamazoo, Michigan.
Sam
L M
LM
Justen
J M
JM
Bundy
G L
GL
Bala
G A
GA
Bleasdale
J E
JE
D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors; D011760:Pyrrolidinones / Q000494:pharmacology*; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors*
D004963:Estrenes; D010972:Platelet Activating Factor; D011760:Pyrrolidinones; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015544:Inositol 1,4,5-Trisphosphate; D007770:L-Lactate Dehydrogenase; D010738:Type C Phospholipases