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Role of protein tyrosine phosphatases in the regulation of interferon‐γ‐induced macrophage nitric oxide generation: implication of ERK pathway and AP‐1 activation
Author(s) -
Blanchette Julie,
Pouliot Philippe,
Olivier Martin
Publication year - 2007
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0505252
Subject(s) - protein tyrosine phosphatase , biology , nitric oxide , mapk/erk pathway , macrophage , phosphatase , tyrosine , microbiology and biotechnology , interferon gamma , interferon , tyrosine kinase , nitric oxide synthase , biochemistry , signal transduction , immunology , immune system , phosphorylation , endocrinology , in vitro
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‐γ‐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‐γ‐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‐1α and NF‐κB, 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‐γ‐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.