Abstract
In murine macrophages, inducible NO synthase II (iNOS or NOS-II) is induced at the transcriptional level by IFN-gamma, alone or synergistically with LPS. We investigated the possible role of reactions of ADP-ribosylation in triggering the signaling pathways involved in NOS-II gene expression. Stimulation with IFN-gamma and/or LPS of RAW 264.7 macrophages, transiently transfected with the NOS-II promoter, was inhibited by ADP-ribosylation inhibitors, indicating that they interfered with the signal(s) responsible for NOS-II gene transcription. We therefore explored the effect of these inhibitors on the activity of IRF-1 and NF kappa B transcription factors known to be involved in NOS-II induction by IFN-gamma and LPS. No effect was observed on IRF-1 activation. However, NF kappa B binding to its target sequence diminished and transfection experiments with an NF kappa B-driven reporter plasmid demonstrating that ADP-ribosylation inhibitors suppressed NF kappa B-dependent promoter activity. These results provide evidence that a step involving ADP-ribosylation is required to activate NF kappa B-mediated gene transcription.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Benzamides / pharmacology
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DNA-Binding Proteins / antagonists & inhibitors
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Enzyme Induction / drug effects*
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Enzyme Inhibitors / pharmacology
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Genes, Reporter / genetics
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Interferon Regulatory Factor-1
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Interferon-gamma / antagonists & inhibitors
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Interferon-gamma / pharmacology
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Lipopolysaccharides / antagonists & inhibitors
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Lipopolysaccharides / pharmacology
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Macrophages / physiology*
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Mice
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NF-kappa B / antagonists & inhibitors*
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Niacinamide / pharmacology
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Nitric Oxide Synthase / metabolism*
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Nitric Oxide Synthase Type II
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Phosphoproteins / antagonists & inhibitors
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Poly(ADP-ribose) Polymerase Inhibitors*
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Promoter Regions, Genetic / genetics
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Transcription Factors / antagonists & inhibitors
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Transcription, Genetic / drug effects*
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Transfection / genetics
Substances
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Benzamides
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DNA-Binding Proteins
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Enzyme Inhibitors
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Interferon Regulatory Factor-1
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Irf1 protein, mouse
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Lipopolysaccharides
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NF-kappa B
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Phosphoproteins
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Poly(ADP-ribose) Polymerase Inhibitors
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Transcription Factors
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Niacinamide
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Interferon-gamma
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3-aminobenzamide
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Nitric Oxide Synthase
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Nitric Oxide Synthase Type II
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Nos2 protein, mouse