title: Role of protein tyrosine phosphatases in the regulation of interferon-{gamma}-induced macrophage nitric oxide generation: implication of ERK pathway and AP-1 activation.
abstract: NO is a potent molecule involved in the cytotoxic events mediated by macrophages (MØ) against microorganisms. We reported previously that inhibition of MØ protein tyrosine phosphatases (PTPs) mediates a protective effect against Leishmania infection, which was NO-dependent. Herein, we show that the PTP inhibitors of the peroxovanadium (pV) class, bpV(phen) and bpV(pic), can similarly increase murine MØ IFN-gamma-induced NO generation. Using various second messenger (JAK2, MEK, Erk1/Erk2, and p38) antagonists, we found that the Erk1/Erk2 pathway was the principal pathway submitted to regulation by PTPs in the context of IFN-gamma-driven MØ activation and increase in NO production. We observed that bpV(phen) increases inducible NO synthase (iNOS) expression, resulting in enhanced NO production, whereas the bpV(pic) increase of NO production does not seem to result from a modulation of iNOS expression. Transcription factors STAT-1alpha and NF-kappaB, recognized for their importance in NO generation, were not affected by the pV treatment. However, AP-1 was strongly activated by bpV(phen) but not by bpV(pic). Collectively, our results suggest that increased IFN-gamma-induced NO production, observed after bpV(phen) treatment, involves the activation of the transcription factor AP-1 by Erk1/Erk2- and stress-activated protein kinase/JNK-dependent transduction mechanisms.
authors.affiliation: Centre de Recherche en Infectiologie and Département de Biologie Médicale, Centre Hospitalier Universitaire de Québec, Pavillon CHUL, Université Laval, Ste-Foy, Québec, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Blanchette
authors.forename: Philippe
authors.initials: P
authors.lastname: Pouliot
authors.forename: Martin
authors.initials: M
authors.lastname: Olivier
mesh_terms: D000818:Animals; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000187:drug effects; D009942:Organometallic Compounds / Q000494:pharmacology; D010618:Phenanthrolines / Q000494:pharmacology; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000502:physiology*; D020123:Sirolimus / Q000494:pharmacology; D013329:Structure-Activity Relationship; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D009942:Organometallic Compounds; D010618:Phenanthrolines; D018808:Transcription Factor AP-1; C119540:oxodiperoxo(pyridine-2-carboxylate)vanadate(V); D009569:Nitric Oxide; C102120:bisperoxo(1,10-phenanthroline)oxovanadate(1-); D007371:Interferon-gamma; D052247:Nitric Oxide Synthase Type II; D048049:Extracellular Signal-Regulated MAP Kinases; D017027:Protein Tyrosine Phosphatases; D020123:Sirolimus