Diclofenac Inhibits $IFN-{\gamma}$ Plus Lipopolysaccharide-Induced iNOS Gene Expression via Suppression of $NF-{\kappa}B$ Activation in RAW 264.7 Macrophages

  • Bae, So-Hyun (Department of Pharmacology, College of Medicine, Chungnam National University) ;
  • Ryu, Young-Sue (Department of Pharmacology, College of Medicine, Chungnam National University) ;
  • Hong, Jang-Hee (Department of Pharmacology, College of Medicine, Chungnam National University) ;
  • Park, Jin-Chan (Department of Pharmacology, College of Medicine, Chungnam National University) ;
  • Kim, Yong-Man (Genetic Pharmacology Unit, National Institute of Neurological Disorders and Stroke) ;
  • Seok, Jeong-Ho (Department of Pharmacology, College of Medicine, Chungnam National University) ;
  • Lee, Jae-Heun (Department of Pharmacology, College of Medicine, Chungnam National University) ;
  • Hur, Gang-Min (Department of Pharmacology, College of Medicine, Chungnam National University)
  • Published : 2001.12.21

Abstract

Diclofenac, a phenylacetic acid derivative, is a widely used non-steroidal anti-inflammatory drug (NSAID) to provide effective relief of inflammation and pain. Nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been implicated as a mediator of inflammation. We examined the inhibitory effects of diclofenac on the induction of iNOS in RAW 264.7 macrophages which were activated with lipopolysaccharide (LPS) plus interferon-gamma $(IFN-{\gamma}).$ Treatment of RAW 264.7 cells with diclofenac and other NSAIDs (aspirin and indomethacin) significantly inhibited NO production and iNOS protein expression induced by LPS plus $IFN-{\gamma}.$ Also, diclofenac but not aspirin and indomethacin, inhibited iNOS mRNA expression and nuclear factor-kappa B $(NF-{\kappa}B)$ binding activity concentration-dependently. Furthermore, transfection of RAW 264.7 cells with iNOS promoter linked to a CAT reporter gene revealed that only diclofenac inhibited the iNOS promoter activity induced by LPS plus $IFN-{\gamma}$ through the $NF-{\kappa}B$ sites of iNOS promoter. Taken together, these suggest that diclofenac may exert its anti-inflammatory effect by inhibiting iNOS gene expression at the transcriptional level through suppression of $NF-{\kappa}B$ activation.