title: p38 mitogen-activated protein kinase regulates cyclooxygenase-2 mRNA stability and transcription in lipopolysaccharide-treated human monocytes.
abstract: p38 mitogen-activated protein kinase (MAPK) is activated by inflammatory stimuli such as bacterial lipopolysaccharide (LPS), interleukin-1, and tumor necrosis factor. We have previously shown that the pyridinyl imidazole SB 203580, which inhibits it, blocks the interleukin-1 induction of cyclooxygenase-2 (COX-2) and matrix metalloproteinase 1 and 3 mRNAs in fibroblasts. Here we explore the role of p38 MAPK in the response of human monocytes to LPS. 0.1 microM SB 203580 significantly inhibited the LPS induction of COX-2 and tumor necrosis factor protein and mRNAs. The activity of MAPK-activated protein kinase-2 (a substrate of p38 MAPK) in the cells was commensurately reduced. Some isoforms of c-jun N-terminal kinase (which is also activated by LPS) are sensitive to SB 203580; the inhibitor had little effect on monocyte c-jun N-terminal kinases up to 2 microM. We investigated the mechanism of inhibition of COX-2 induction. Transcription (measured by a nuclear run-on assay) was 60% inhibited by SB 203580 (2 microM). Importantly, we found that p38 MAPK was essential for stabilizing COX-2 mRNA: when cells stimulated for 4 h with LPS were treated with actinomycin D, COX-2 mRNA decayed slowly. Treatment of stimulated cells with 2 microM SB 203580 caused a rapid disappearance of COX-2 mRNA, even with actinomycin D present. We conclude p38 MAPK plays a role in the transcription and stabilization of COX-2 mRNA.
authors.affiliation: Kennedy Institute of Rheumatology, 1 Aspenlea Road, Hammersmith, London W6 8LH, United Kingdom.
authors.forename: J L
authors.initials: JL
authors.lastname: Dean
authors.forename: M
authors.initials: M
authors.lastname: Brook
authors.forename: A R
authors.initials: AR
authors.lastname: Clark
authors.forename: J
authors.initials: J
authors.lastname: Saklatvala
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051546:Cyclooxygenase 2; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics*; D048031:JNK Mitogen-Activated Protein Kinases; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases; D009000:Monocytes / Q000187:drug effects* / Q000201:enzymology; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics*; D014158:Transcription, Genetic; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D007527:Isoenzymes; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D011725:Pyridines; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580