title: AP-1 activation through endogenous H(2)O(2) generation by alveolar macrophages.
abstract: Reactive oxygen species released during the respiratory burst are known to participate in cell signaling. Here we demonstrate that hydrogen peroxide produced by the respiratory burst activates AP-1 binding. Stimulation of the macrophage cell line NR8383 with respiratory burst agonists ADP and C5a increased AP-1 binding activity. Importantly, this increase in binding was blocked by catalase, confirming mediation by endogenous H(2)O(2). Moreover, exogenously added H(2)O(2) mimicked the agonists, and also activated AP-1. Antibodies revealed that the activated AP-1 complex is composed predominantly of c-Fos/c-Jun heterodimers. Treatment of the cells with ADP, C5a and H(2)O(2) (100 microM) all increased the phosphorylation of c-Jun. c-Fos protein was increased in cells treated with C5a or high dose (200 microM) H(2)O(2), but not in cells treated with ADP. The MEK inhibitor, PD98059, partially blocked the C5a-mediated increase in AP-1 binding. A novel membrane-permeable peptide inhibitor of JNK, JNKi, also inhibited AP-1 activation. Together these data suggest that C5a-mediated AP-1 activation requires both the activation of the ERK and JNK pathways, whereas activation of the JNK pathway is sufficient to increase AP-1 binding with ADP. Thus, AP-1 activation joins the list of pathways for which the respiratory burst signals downstream events in the macrophage.
authors.affiliation: Department of Environmental Health Sciences, University of Alabama at Birmingham, 35294-0022, USA.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Iles
authors.forename: Dale A
authors.initials: DA
authors.lastname: Dickinson
authors.forename: Nobuo
authors.initials: N
authors.lastname: Watanabe
authors.forename: Takeo
authors.initials: T
authors.lastname: Iwamoto
authors.forename: Henry Jay
authors.initials: HJ
authors.lastname: Forman
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay; D004791:Enzyme Inhibitors; D005419:Flavonoids / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D016676:Macrophages, Alveolar / Q000187:drug effects* / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D051381:Rats; D017382:Reactive Oxygen Species; D016897:Respiratory Burst / Q000187:drug effects*; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D000244:Adenosine Diphosphate; D006861:Hydrogen Peroxide; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one