Investigation on the effect of experimental phospholipase A2 inhibitors on the formyl-methionyl-leucyl-phenylalanine-stimulated chemotaxis of human leukocytes in vitro.
We investigated the effects of phospholipase A2 (PLA2) activation and inhibition on the chemotaxis of mixed human leukocytes (MHL) in a 48-well microchemotaxis chamber and on the production of leukotriene B4 (LTB4) by an enzyme immuno assay. LTB4 is the eicosanoid which is most likely responsible for induction of chemotaxis and its production can be used as an indicator of PLA2 stimulation. Formyl-methionyl-leucyl-phenylalanine (F-met-leu-phe, f-MLP), a well known inducer of PLA2 in our experiments stimulated dose-dependently the chemotaxis of MHL with a maximum at 10 nmol/l. In accordance with the chemotaxis assay the maximum LTB4-production was found at 10 nmol/l f-MLP. The preincubation of MHL with the PLA2 inhibitors mepacrine (1-100 mumol/l), manoalide (1-100 mumol/l) and BM 16.2115 (1,6-dioxadispiro[4.1.5.1]trideca-8,11-diene-2,10-dione, 0.5-50 mumol/l) dose-dependently reduced the chemotaxis of MHL induced by 10 nmol/l f-MLP. The inhibitory effect of the experimental compound BM 16.2115 was about 2 times stronger than those of the reference compounds mepacrine and manoalide. Thus inhibitors of PLA2 reduce chemotaxis of leukocytes probably by reducing production of LTB4. This mechanism could be of considerable interest for the development of anti-inflammatory drugs.
Hinder
M
M
Department of Pharmacology, Boehringer Mannheim GmbH, Germany.
D002470:Cell Survival / Q000187:drug effects; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007958:Leukocyte Count / Q000187:drug effects; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism*; D007975:Leukotriene B4 / Q000096:biosynthesis; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D013141:Spiro Compounds / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D013141:Spiro Compounds; C111593:BM 162115; D007975:Leukotriene B4; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010741:Phospholipases A; D054467:Phospholipases A2