Increase in cell responses and protein phosphorylation of neutrophils induced by synthetic diacylglycerols.
Diacylglycerols (DG) induced various stimulation-coupled responses of guinea pig peritoneal neutrophils (GPPMN), such as superoxide (O2-.) generation, luminol chemiluminescence response (LCL) and membrane depolarization. These activities induced by L-alpha-1,2-dioctanoyl glycerol (diC8) are quite similar to those induced by phorbol 12-myristate 13-acetate (PMA). The effects of diC8 were much stronger than those of L-alpha-1-oleoyl-2-acetylglycerol (OAG) and no effect was produced by L-alpha-1,2-dioleoyl glycerol (DO). Concentrations of diC8 and OAG for maximal O2-. generation were 1 and 10 microM, respectively. However, rat brain Ca(2+)- and phospholipid-dependent protein kinase (PKC) was activated by all DGs used, and the concentrations of OAG, DO and diC8 for half maximum stimulation were 0.2, 1.0 and 2.0 microM, respectively. Discrepancies between the concentrations of DGs required for O2-. release and PKC activation might be due to differences in their affinity for and permeability in the membrane. The generation of active oxygen and the PKC activity were both sensitive to PKC inhibitors, such as 1-(5-isoquinolinesulfonyl)-2-methyl-piperazine (H-7) and staurosporine. ID50 of H-7 and staurosporine for the inhibition of diC8-induced O2-. release were 150 nM and 10 nM, respectively. By contrast, staurosporine does not inhibit diC8 induced membrane depolarization. Phosphorylation of cytoplasmic proteins, such as the 47 kDa protein, was increased by DGs and this phosphorylation was also inhibited by H-7 or staurosporine. The capacities of stimulating the rates of 47 kDa protein phosphorylation were in the order diC8 > OAG > DO. These results suggest the involvement of protein phosphorylation in DG-induced O2-. generation. However, a part of the O2-. generation induced by high concentration of DG might have occurred via a PKC-independent pathway.
Kawada
M
M
Department of Cell Chemistry, Okayama University Medical School, Japan.
Edashige
K
K
Watanabe
Y
Y
Yasuda
T
T
Utsumi
K
K
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D001386:Azides / Q000494:pharmacology; D001798:Blood Proteins / Q000378:metabolism*; D001921:Brain / Q000201:enzymology; D004075:Diglycerides / Q000494:pharmacology*; D006168:Guinea Pigs; D007546:Isoquinolines / Q000494:pharmacology; D007700:Kinetics; D008163:Luminescent Measurements; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000097:blood*; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D019810:Sodium Azide; D013329:Structure-Activity Relationship; D013481:Superoxides / Q000097:blood*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D001386:Azides; D001798:Blood Proteins; D004075:Diglycerides; D007546:Isoquinolines; D010750:Phosphoproteins; D010879:Piperazines; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D019810:Sodium Azide; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate