AP-1 activation through endogenous H(2)O(2) generation by alveolar macrophages.
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.
Iles
Karen E
KE
Department of Environmental Health Sciences, University of Alabama at Birmingham, 35294-0022, USA.
Dickinson
Dale A
DA
Watanabe
Nobuo
N
Iwamoto
Takeo
T
Forman
Henry Jay
HJ
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*
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