Requirement of hydrogen peroxide generation in TGF-beta 1 signal transduction in human lung fibroblast cells: involvement of hydrogen peroxide and Ca2+ in TGF-beta 1-induced IL-6 expression.
Stimulation of human lung fibroblast cells with TGF-beta1 resulted in a transient burst of reactive oxygen species with maximal increase at 5 min after treatment. This reactive oxygen species increase was inhibited by the antioxidant, N-acetyl-l -cysteine (NAC). TGF-beta1 treatment stimulated IL-6 gene expression and protein synthesis in human lung fibroblast cells. Antioxidants including NAC, glutathione, and catalase reduced TGF-beta1-induced IL-6 gene expression, and direct H2O2 treatment induced IL-6 expression in a dose-dependent manner. NAC also reduced TGF-beta1-induced AP-1 binding activity, which is involved in IL-6 gene expression. It has been reported that Ca2+ influx is stimulated by TGF-beta1 treatment. EGTA suppressed TGF-beta1- or H2O2-induced IL-6 expression, and ionomycin increased IL-6 expression, with simultaneously modulating AP-1 activity in the same pattern. PD98059, an inhibitor of mitogen-activated protein kinase (MAPK) kinase/extracellular signal-related kinase kinase 1, suppressed TGF-beta1- or H2O2-induced IL-6 and AP-1 activation. In addition, TGF-beta1 or H2O2 increased MAPK activity which was reduced by EGTA and NAC, suggesting that MAPK is involved in TGF-beta1-induced IL-6 expression. Taken together, these results indicate that TGF-beta1 induces a transient increase of intracellular H2O2 production, which regulates downstream events such as Ca2+ influx, MAPK, and AP-1 activation and IL-6 gene expression.
Laboratory of Immunology, Korea Research Institute of Bioscience and Biotechnology, Taejon, Republic of Korea.
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Junn
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Lee
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Ju
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Han
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Im
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Kang
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Lee
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Bae
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Lee
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Rhee
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Choi
D002118:Calcium / Q000502:physiology*; D004533:Egtazic Acid / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D007424:Intracellular Fluid / Q000276:immunology / Q000378:metabolism; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000502:physiology*; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D005419:Flavonoids; D015850:Interleukin-6; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D016212:Transforming Growth Factor beta; D004533:Egtazic Acid; D006861:Hydrogen Peroxide; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium