title: Oxidative stress triggers STAT3 tyrosine phosphorylation and nuclear translocation in human lymphocytes.
abstract: Oxidizing agents are powerful activators of factors responsible for the transcriptional activation of cytokine-encoding genes involved in tissue injury. In this study we show evidence that STAT3 is a transcription factor whose activity is modulated by H2O2 in human lymphocytes, in which endogenous catalase had previously been inhibited. H2O2-induced nuclear translocation of STAT3 to form sequence-specific DNA-bound complexes was evidenced by immunoblotting of nuclear fractions and electrophoretic mobility shift assays, and vanadate was found to strongly synergize with H2O2. Moreover, anti-STAT3 antibodies specifically precipitated a protein of 92 kDa that becomes phosphorylated on tyrosine upon lymphocyte treatment with H2O2. Phenylarsine oxide, a tyrosine phosphatase inhibitor, and genistein, a tyrosine kinase inhibitor, cooperated and cancelled, respectively, the H2O2-promoted STAT3 nuclear translocation. Evidence is also presented, using Fe2+/Cu2+ ions, that.OH generated from H2O2 through Fenton reactions could be a candidate oxygen reactive species to directly activate STAT3. Present data suggest that H2O2 and vanadate are likely to inhibit the activity of intracellular tyrosine phosphatase(s), leading to enhanced STAT3 tyrosine phosphorylation and hence its translocation to the nucleus. These results demonstrate that the DNA binding activity of STAT3 can be modulated by oxidizing agents and provide a framework to understand the effects of oxidative stress on the JAK-STAT signaling pathway.
authors.affiliation: Departamento de Bioquímica Médica y Biología Molecular, Facultad de Medicina, Universidad de Sevilla, 41009 Sevilla, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Carballo
authors.forename: M
authors.initials: M
authors.lastname: Conde
authors.forename: R
authors.initials: R
authors.lastname: El Bekay
authors.forename: J
authors.initials: J
authors.lastname: Martín-Nieto
authors.forename: M J
authors.initials: MJ
authors.lastname: Camacho
authors.forename: J
authors.initials: J
authors.lastname: Monteseirín
authors.forename: J
authors.initials: J
authors.lastname: Conde
authors.forename: F J
authors.initials: FJ
authors.lastname: Bedoya
authors.forename: F
authors.initials: F
authors.lastname: Sobrino
mesh_terms: D001152:Arsenicals / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D003300:Copper / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003958:Diamide / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000494:pharmacology; D008214:Lymphocytes / Q000378:metabolism*; D018384:Oxidative Stress; D010618:Phenanthrolines / Q000494:pharmacology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000032:analysis; D010835:Phytohemagglutinins / Q000494:pharmacology; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D017382:Reactive Oxygen Species; D050796:STAT3 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
chemical_list: D001152:Arsenicals; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D010618:Phenanthrolines; D010835:Phytohemagglutinins; D017382:Reactive Oxygen Species; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D015534:Trans-Activators; C029341:oxophenylarsine; D003958:Diamide; D019000:Phosphotyrosine; D014638:Vanadates; D014443:Tyrosine; D003300:Copper; D006861:Hydrogen Peroxide; D019833:Genistein; D007501:Iron; D017027:Protein Tyrosine Phosphatases; C025205:1,10-phenanthroline