The role of p38 mitogen-activated protein kinase in IL-1 beta transcription.
Several reports have shown that bicyclic imidazoles, specific inhibitors of the p38 mitogen-activated protein kinase (MAPK), block cytokine synthesis at the translational level. In this study, we examined the role of p38 MAPK in the regulation of the IL-1beta cytokine gene in monocytic cell lines using the bicyclic imidazole SB203580. Addition of SB203580 30 min before stimulation of monocytes with LPS inhibited IL-1beta protein and steady state message in a dose-dependent manner in both RAW264.7 and J774 cell lines. The loss of IL-1beta message was due mainly to inhibition of transcription, since nuclear run-off analysis showed an approximately 80% decrease in specific IL-1 RNA synthesis. In contrast, SB203580 had no effect on the synthesis of TNF-alpha message. LPS-stimulated p38 MAPK activity in the RAW264.7 cells was blocked by SB203580, as measured by the inhibition of MAPKAP2 kinase activity, a downstream target of the p38 MAPK. CCAATT/enhancer binding protein (C/EBP)/NFIL-6-driven chloramphenicol acetyltransferase (CAT) reporter activity was sensitive to SB203580, indicating that C/EBP/NFIL-6 transcription factor(s) are also targets of p38 MAPK. In contrast, transfected CAT constructs containing NF-kappaB elements were only partially inhibited (approximately 35%) at the highest concentration of SB203580 after LPS stimulation. As measured by EMSA, LPS-stimulated NF-kappaB activation was not affected by SB203580. Overall, the results demonstrate, for the first time, a role for p38 MAPK in IL-1beta transcription by acting through C/EBP/NFIL-6 transcription factors.
Baldassare
J J
JJ
Department of Pharmacological and Physiological Sciences, St. Louis University School of Medicine, St. Louis, MO 63104, USA.
Bi
Y
Y
Bellone
C J
CJ
D000818:Animals; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017930:Genes, Reporter / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics; D007424:Intracellular Fluid / Q000187:drug effects / Q000201:enzymology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D020928:Mitogen-Activated Protein Kinases; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000378:metabolism; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000187:drug effects / Q000276:immunology*; D048051:p38 Mitogen-Activated Protein Kinases; D000093242:Interleukin-6 Inhibitors
D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D015500:Chloramphenicol O-Acetyltransferase; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D007375:Interleukin-1; D015850:Interleukin-6; D020928:Mitogen-Activated Protein Kinases; D009687:Nuclear Proteins; D011500:Protein Synthesis Inhibitors; D011725:Pyridines; D012333:RNA, Messenger; D014157:Transcription Factors; D048051:p38 Mitogen-Activated Protein Kinases; D000093242:Interleukin-6 Inhibitors; C497253:Cebpd protein, mouse; C093642:SB 203580