Salicylate Is a Transcriptional Inhibitor of the Inducible Nitric Oxide Synthase in Cultured Cardiac Fibroblasts

• Published in: The Journal of biological chemistry 1996-12, Vol.271 (49), p.31585-31592
• Main Authors: Farivar, R. Saeid, Brecher, Peter
• Format: Article
• Language: English
• Subjects: Animals; Blotting, Northern; Cells, Cultured; Dexamethasone - pharmacology; DNA-Binding Proteins - metabolism; Dose-Response Relationship, Drug; Enzyme Induction - drug effects; Fibroblasts - enzymology; Interferon-gamma - pharmacology; Mice; Myocardium - enzymology; NF-kappa B - metabolism; Nitric Oxide Synthase - biosynthesis; Salicylates - pharmacology; Salicylic Acid; Sodium Salicylate - pharmacology; STAT1 Transcription Factor; Time Factors; Trans-Activators - metabolism; Transcription, Genetic - drug effects; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.271.49.31585

We have previously reported that salicylate inhibits the inducible NO synthase (NOS 2) in cytokine-induced cardiac fibroblasts (Farivar, R. S., Chobanian, A. V., and Brecher, P. (1996) Circ. Res. 78, 759-768). To define further the mechanism of inhibition of NOS 2 by salicylate, we investigated NOS 2 mRNA induction by cytokines and determined the kinetics of inhibition by salicylate as compared to dexamethasone. Interferon-γ plus tumor necrosis factor-α induced NOS 2 mRNA synergistically in a time- and dose-dependent manner. Both dexamethasone and salicylate equally inhibited the induction of NOS 2 mRNA in a time- and dose-dependent fashion, both before and after cytokine induction. Salicylate also inhibited interferon-γ plus interleukin-1β-induced NOS 2 mRNA. After 24 h of cytokine stimulation, salicylate stopped the induction of NOS 2 mRNA, whereas dexamethasone delayed the accumulation of transcript. In half-life experiments of NOS 2 mRNA, we found that dexamethasone reduced the half-life of NOS 2 mRNA from 7 to 4 h, whereas salicylate had no effect on mRNA stability. Tumor necrosis factor-α and interferon-γ induced NF-κB (p50/p65) and STAT-1, respectively, as assessed by gel shift assays. Salicylate did not inhibit the cytokine induction of NF-κB or STAT-1. This study suggests that the anti-inflammatory mechanism of salicylate involves inhibition of NOS 2 transcription and shows that the effect is independent of NF-κB activation.