Abstract
Monocytic THP-1 cells expressed tumour necrosis factor-alpha (TNF-alpha) mRNA, but hardly any detectable TNF-alpha protein and a partially activated MAP kinase ERK-2 in the unstimulated state. Stimulation with phorbol ester led to expression of TNF-alpha protein without significant changes in mRNA, a response that was sensitive to the MEK-1/2 inhibitors PD98059 and U0126. A calcium signal also led to expression of TNF-alpha protein, but now accompanied by a rapid increase in mRNA. A synergistic effect between phorbol ester and calcium ionophore was evident at the level of TNF-alpha protein, but not its mRNA. Stimulation with anisomycin led to a TNF-alpha expression that was sensitive to the p38 inhibitor SB203580. Actinomycin D lowered TNF-alpha mRNA in a similar way as PD98059 but was less inhibitory on PMA- or anisomycin-induced formation of TNF-alpha, thus confirming that these agents acted by causing translational derepression. Thus, in THP-1 cells MAP kinase pathways involving MEK-1/2 and possibly ERK-2 as well as the human p38 analogue were essential for basal TNF-alpha mRNA expression and translational activation.
Copyright 2000 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anisomycin / pharmacology
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Blotting, Northern
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Blotting, Western
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Butadienes / pharmacology
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Calcium / metabolism
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Cell Line
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Cycloheximide / pharmacology
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Dactinomycin / pharmacology
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Dose-Response Relationship, Drug
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Enzyme Inhibitors / pharmacology
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Flavonoids / pharmacology
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Humans
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Imidazoles / pharmacology
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Ionophores / pharmacology
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MAP Kinase Signaling System
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinases / metabolism
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Monocytes / metabolism
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Nitriles / pharmacology
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Protein Biosynthesis
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Protein Synthesis Inhibitors / pharmacology
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Pyridines / pharmacology
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RNA, Messenger / metabolism
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Signal Transduction*
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Tetradecanoylphorbol Acetate / pharmacology
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Time Factors
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Tumor Necrosis Factor-alpha / biosynthesis
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Tumor Necrosis Factor-alpha / metabolism*
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p38 Mitogen-Activated Protein Kinases
Substances
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Butadienes
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Enzyme Inhibitors
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Flavonoids
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Imidazoles
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Ionophores
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Nitriles
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Protein Synthesis Inhibitors
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Pyridines
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RNA, Messenger
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Tumor Necrosis Factor-alpha
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U 0126
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Dactinomycin
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Anisomycin
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Cycloheximide
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinases
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p38 Mitogen-Activated Protein Kinases
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Tetradecanoylphorbol Acetate
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SB 203580
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2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
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Calcium