Formation of diacylglycerol, inositol phosphates, arachidonic acid and its metabolites in macrophages.
Treatment of macrophages with zymosan, 4 beta-phorbol 12-myristate 13-acetate (PMA) and fluoride but not with A 23187 or arachidonic acid (delta Ach) leads to a generation of diacylglycerol (acyl2Gro). Formation of inositol phosphates is achieved with zymosan, only. An elevation of intracellular calcium is obtained with zymosan and A 23187 but not with PMA, fluoride or delta Ach. Prior treatment of the cells with phorbol ester for 3 h which has been shown recently to result in a down-regulation of protein kinase (PK) C-beta but not PKC-delta [Duyster, J., Schwende, H., Fitzke, E., Hidaka H. & Dieter P. (1993) Biochem. J. 292, 203-207] has no effect on the zymosan-induced formation of acyl2Gro or inositol phosphates but inhibits the PMA-induced generation of acyl2Gro. Down-regulation of PKC-delta by prior phorbol ester treatment for 24 h augments the zymosan-induced generation of acyl2Gro and inositol phosphates. The acyl2Gro lipase inhibitor RG 80267 inhibits the PMA-induced and fluoride-induced generation of prostaglandin (PG) E2, reduces the zymosan-induced release of PGE2 by 50% but has no effect on PGE2 formation of unstimulated, A 23187-treated or delta Ach-treated cells. Furthermore, RG 80267 enhances accumulation of delta Ach-labeled acyl2Gro in response to zymosan, PMA and fluoride. These data indicate that zymosan activates a phosphatidylinositol 4,5-bisphosphate-specific phospholipase (PL) C, that generation of acyl2Gro by PMA and fluoride occurs via hydrolysis of other phospholipids, that PKC-beta is involved in the PMA-induced generation of acyl2Gro and PKC-delta negatively modulates the zymosan-induced activation of PLC and PMA and fluoride induce a liberation of delta Ach from acyl2Gro, A 23187 activates the PLA2 pathway and zymosan stimulates both, the acyl2Gro- and PLA2-pathway.
Dieter
P
P
Institute of Molecular Cell Biology, University of Freiburg, Germany.
Fitzke
E
E
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism / Q000494:pharmacology*; D000001:Calcimycin / Q000494:pharmacology; D002478:Cells, Cultured; D003512:Cyclohexanones / Q000494:pharmacology; D004075:Diglycerides / Q000096:biosynthesis*; D005459:Fluorides / Q000494:pharmacology; D007295:Inositol Phosphates / Q000096:biosynthesis*; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015054:Zymosan / Q000494:pharmacology
D003512:Cyclohexanones; D004075:Diglycerides; D007295:Inositol Phosphates; D016718:Arachidonic Acid; D000001:Calcimycin; C036535:1,6-bis(cyclohexyloximinocarbonyl)hexane; D015054:Zymosan; D013755:Tetradecanoylphorbol Acetate; D005459:Fluorides