Differential regulation of neutrophil phospholipase d activity and degranulation.
One of the proposed functions of phosphatidic acid (PA) formation from phospholipase D (PLD) activation in neutrophils is to promote degranulation induced by receptor agonists. The present study shows that the time course and dose response of PA formation and degranulation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) differed. PLD activation and degranulation also exhibited different dose response to genistein and epigallocatechin gallate (EGCG), inhibitors of protein tyrosine kinases. Genistein inhibited PLD activity with an IC(50) value of 12.2 microM in fMLP- and 107 microM in phorbol myristate acetate (PMA)-stimulated cells. It required higher concentrations of genistein to inhibit degranulation than to inhibit PLD activity induced by fMLP. EGCG in the range of 40-400 microM had no effect on PLD activity but it inhibited the release of beta-glucuronidase and elastase by fMLP-stimulated cells. These results demonstrate differential regulation of PLD activity and degranulation of primary granules by genistein and EGCG in fMLP-stimulated neutrophils.
Tou
Jen Sie
JS
Department of Biochemistry, Tulane University Health Sciences Center, 1430 Tulane Avenue, New Orleans, Louisiana 70112, USA. jtou@tulane.edu
D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D015550:Cell Degranulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D005966:Glucuronidase / Q000378:metabolism; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000378:metabolism; D010712:Phosphatidic Acids / Q000096:biosynthesis / Q000494:pharmacology; D010739:Phospholipase D / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects; D013267:Stilbenes / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004791:Enzyme Inhibitors; D010712:Phosphatidic Acids; D013267:Stilbenes; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002392:Catechin; C045651:epigallocatechin gallate; D019833:Genistein; D010739:Phospholipase D; D005966:Glucuronidase; D010196:Pancreatic Elastase; D013755:Tetradecanoylphorbol Acetate; D000077185:Resveratrol