A diacylglycerol kinase inhibitor, R 59 022, potentiates superoxide anion production and 46-kDa protein phosphorylation in guinea pig polymorphonuclear leukocytes.
A diacylglycerol (DG) kinase inhibitor, R 59 022, potentiated superoxide anion (O2-) production in guinea pig polymorphonuclear leukocytes (PMNL) induced by N-formyl-methionyl-leucyl-phenylalanine (FMLP). R 59 022 also potentiated O2- production induced by 1-oleoyl-2-acetylglycerol, a permeable DG. However, the production induced by phorbol 12-myristate 13-acetate (PMA), a direct activator for protein kinase C, was not potentiated by R 59 022. R 59 022 by itself had no significant effects on unstimulated O2- production. The potentiation of FMLP-induced O2- production by R 59 022 was correlated closely with increased formation of DG and decreased formation of phosphatidic acid, a product of DG kinase. R 59 022 had no effect on the breakdown of phosphoinositides. Phosphorylation of 46-kDa protein(s) by protein kinase C was also examined in relation to O2- production in PMNL. In coincidence with the increase in O2- production, the phosphorylation was potentiated by R 59 022 in the response to FMLP, but not in the response to PMA. In addition, staurosporine, a protein kinase C inhibitor, inhibited increases in both O2- production and phosphorylation of the 46-kDa protein(s) after PMA stimulation. Similar inhibitory effects of staurosporine were also observed upon stimulation with FMLP, irrespective of the presence of R 59 022. These results indicate that retention of DG as a result of the inhibition of further metabolism induces marked stimulation of O2- production via protein kinase C activation in PMNL. These results also provide further evidence for the close relationship between 46-kDa protein phosphorylation by protein kinase C and stimulation of O2- production in PMNL.
Ohtsuka
T
T
Department of Physiological Chemistry, Hiroshima University, School of Medicine, Japan.
Hiura
M
M
Yoshida
K
K
Okamura
N
N
Ishibashi
S
S
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D019852:Diacylglycerol Kinase; D005260:Female; D006168:Guinea Pigs; D007700:Kinetics; D008970:Molecular Weight; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010743:Phospholipids / Q000096:biosynthesis; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000302:isolation & purification; D010766:Phosphorylation; D010770:Phosphotransferases / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors; D011744:Pyrimidinones / Q000494:pharmacology*; D019311:Staurosporine; D013481:Superoxides / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology*
D000470:Alkaloids; D010743:Phospholipids; D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D011744:Pyrimidinones; D013844:Thiazoles; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; C047505:R 59022; D010770:Phosphotransferases; D019852:Diacylglycerol Kinase; D019311:Staurosporine