JNK (c-Jun NH2-terminal kinase) is a target for antioxidants in T lymphocytes.
AP-1 has been shown to behave as a redox-sensitive transcription factor that can be activated by both oxidant and antioxidant stimuli. However, the mechanisms involved in the activation of AP-1 by antioxidants are largely unknown. In this study we show that the structurally unrelated antioxidant agents pyrrolidine dithiocarbamate (PDTC), butylated hydroxyanisole, and Nacetylcysteine activated JNK (c-Jun NH2-terminal kinase) in Jurkat T cells. This activation differed substantially from that mediated by phorbol 12-myristate 13-acetate (PMA) and Ca2+ ionophore or produced by costimulation with antibodies against the T cell receptor-CD3 complex and to CD28. The activation of JNK by classical T cell stimuli was transient, whereas that mediated by PDTC and butylated hydroxyanisole (but not N-acetylcysteine) was sustained. The kinetics of JNK activation correlated with the expression of c-jun which was transient after stimulation with PMA plus ionophore and prolonged in response to PDTC, which also transiently induced c-fos. In addition, JNK activation by PMA plus ionophore was sensitive to inhibitors of signaling pathways involving Ca2+, protein kinase C, and tyrosine phosphorylation, which failed to inhibit the activation mediated by PDTC. Transfection of trans-dominant negative expression vectors of ras and raf, together with AP-1-dependent reporter constructs, as well as Western blot analysis using anti-ERK (extracellular signal-regulated kinase) antibodies, indicated that the Ras/Raf/ERK pathway did not appear to mediate the effect of the antioxidant. However, the combined treatment with PDTC and PMA, two agents that synergize on AP-1 activation, resulted in the persistent phosphorylation of ERK-2. In conclusion, our results identify JNK as a target of antioxidant agents which can be regulated differentially under oxidant and antioxidant conditions.
Gómez del Arco
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P
Centro de Biología Molecular y Servicio de Inmunología, Hospital de la Princesa, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Cantoblanco, Madrid 28006, Spain.
Martínez-Martínez
S
S
Calvo
V
V
Armesilla
A L
AL
Redondo
J M
JM
D000975:Antioxidants / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013859:Thiocarbamates / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism*
D000975:Antioxidants; D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011759:Pyrrolidines; D012333:RNA, Messenger; D013859:Thiocarbamates; D018808:Transcription Factor AP-1; C020972:pyrrolidine dithiocarbamic acid; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate