title: Clofazimine-mediated regulation of human polymorphonuclear leukocyte migration by pro-oxidative inactivation of both leukoattractants and cellular migratory responsiveness.
abstract: The effects of clofazimine (0.15-20 micrograms/ml) on the spontaneous and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-stimulated migration, membrane-associated oxidative metabolism, degranulation and production of prostaglandin (PG) E2 by human polymorphonuclear in vitro have been investigated. Clofazimine at concentrations of 0.3 microgram/ml and greater significantly increased both the spontaneous and FMLP-stimulated chemiluminescence (CL), hexose monophosphate shunt (HMS) activity, myeloperoxidase-mediated protein iodination, auto-iodination, degranulation and PGE2 production by PMNL. At the same concentrations clofazimine inhibited both random and leukoattractant-induced migration of PMNL. Inhibition of PMNL migration by clofazimine was due to both a cell-directed auto-oxidative mechanism and by functional inactivation of FMLP. Clofazimine mediated inhibition of PMNL migration was prevented by the anti-oxidants cysteine and dapsone but not by the potent inhibitors of PG synthetase indomethacin and piroxicam. Anti-oxidants also protected FMLP from functional inactivation by clofazimine-exposed PMNL. Clofazimine increased both the spontaneous and FMLP-stimulated production of PGE2 by PMNL from four children with chronic granulomatous disease (CGD). Clofazimine is not an oxidising agent nor did it stimulate membrane-associated oxidative metabolism in CGD or NaF-pulsed normal PMNL. These data show that clofazimine-mediated inhibition of PMNL migration is dependent on intact cellular membrane-associated oxidative metabolism. Clofazimine is therefore a pro-oxidative anti-inflammatory agent.
mesh_terms: D000328:Adult; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D002991:Clofazimine / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008163:Luminescent Measurements; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D010084:Oxidation-Reduction; D010427:Pentose Phosphate Pathway / Q000187:drug effects; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology
chemical_list: D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D009240:N-Formylmethionine Leucyl-Phenylalanine; D012969:Sodium Fluoride; D002991:Clofazimine