Abstract
1. Cyclooxygenase (COX)-2 expression and activity in response to pro-inflammatory cytokines TNF alpha and IFN gamma was evaluated in the colonic epithelial cell line HT29 and the airway epithelial cell line A549. 2. TNF alpha induced concentration- and time-dependent upregulation of COX-2 mRNA, protein and prostaglandin (PG)E(2) synthesis. 3. Co-stimulation of TNF alpha with IFN gamma resulted in reduced COX-2 mRNA and protein expression. 4. IFN gamma had no effect on the stability of TNF alpha-induced COX-2 mRNA. 5. TNF alpha-induced PGE(2) biosynthesis was significantly enhanced by the simultaneous addition of IFN gamma and was COX-2 dependent. 6. The combination of IFN gamma and TNF alpha induced the microsomal prostaglandin E synthase (mPGES), comensurate with the enhanced PGE(2) synthesis. 7. These results suggest that, in terms of PGE(2) biosynthesis, IFN gamma plays a negative regulatory role at the level of COX-2 expression and a positive regulatory role at the level of mPGES expression. This may have important implications for the clinical use of IFN gamma in inflammatory diseases.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Caco-2 Cells
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Colon / drug effects
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Colon / metabolism*
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Colon / pathology
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Cyclooxygenase Inhibitors / metabolism
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Dactinomycin / pharmacology
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Dose-Response Relationship, Drug
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Drug Therapy, Combination
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Epithelial Cells / drug effects
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Epithelial Cells / metabolism*
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Epithelial Cells / pathology
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Evaluation Studies as Topic
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HT29 Cells
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Humans
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Interferon-alpha / metabolism
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Interferon-alpha / pharmacology
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Interferon-gamma / antagonists & inhibitors
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Interferon-gamma / metabolism
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Interferon-gamma / pharmacology*
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Intramolecular Oxidoreductases / genetics
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Intramolecular Oxidoreductases / metabolism
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Mice
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Microsomes / enzymology
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Prostaglandin-E Synthases
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Prostaglandins E / biosynthesis*
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Tumor Necrosis Factor-alpha / drug effects
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Tumor Necrosis Factor-alpha / metabolism
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Tumor Necrosis Factor-alpha / pharmacology
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Up-Regulation
Substances
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Cyclooxygenase Inhibitors
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Interferon-alpha
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Prostaglandins E
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RNA, Messenger
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Tumor Necrosis Factor-alpha
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Dactinomycin
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Interferon-gamma
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Intramolecular Oxidoreductases
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Prostaglandin-E Synthases