Fluoride activates diradylglycerol and superoxide generation in human neutrophils via PLD/PA phosphohydrolase-dependent and -independent pathways.
In contrast to the rapid, ethanol-inhibited superoxide generation by the receptor-linked agonist formyl-methionyl-leucyl-phenylalanine (fMLP), fluoride-activated superoxide generation occurs after a prolonged lag, and as shown herein is relatively ethanol-insensitive. We have investigated fluoride-activation of diradylglycerol generation and phospholipase D activity. Fluoride induces a very large increase in diradylglycerol mass (both 1,2-diacylglycerol (DAG) and 1-O-alkyl,2-acylglycerol (EAG)), with kinetics similar to superoxide generation. Unlike fMLP-activated diglyceride generation which is completely inhibited by ethanol, that produced by fluoride is only partially (30%) blocked. When the phosphatidylcholine pool is 3H-prelabeled, fluoride activates both [3H]phosphatidic acid (PA) and [3H]diglyceride generation with similar kinetics. Partial inhibition of the production of these species by ethanol was seen, coincident with the appearance of [3H]phosphatidylethanol, indicating phospholipase D-dependent transphosphatidylation had occurred. The data are consistent with the fluoride activation of PA and diglyceride generation by both phospholipase D-dependent and -independent (presumably phospholipase C) mechanisms.
Olson
S C
SC
Department of Biochemistry, Emory University Medical School, Atlanta, GA 30322.
Tyagi
S R
SR
Lambeth
J D
JD
D004075:Diglycerides / Q000097:blood*; D000431:Ethanol / Q000494:pharmacology; D007700:Kinetics; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010711:Phosphatidate Phosphatase / Q000097:blood*; D010712:Phosphatidic Acids / Q000097:blood; D010714:Phosphatidylethanolamines / Q000097:blood; D010739:Phospholipase D / Q000097:blood*; D012969:Sodium Fluoride / Q000494:pharmacology*; D013481:Superoxides / Q000097:blood*
C011439:1,2-diacylglycerol; D004075:Diglycerides; D010712:Phosphatidic Acids; D010714:Phosphatidylethanolamines; D013481:Superoxides; D000431:Ethanol; D009240:N-Formylmethionine Leucyl-Phenylalanine; C035561:diarachidonyl diglyceride; D012969:Sodium Fluoride; D010711:Phosphatidate Phosphatase; D010739:Phospholipase D