title: Acetaminophen inhibits iNOS gene expression in RAW 264.7 macrophages: differential regulation of NF-kappaB by acetaminophen and salicylates.
abstract: Acetaminophen is a widely used analgesic and anti-inflammatory drug that is considered a good alternative to salicylates for individuals who cannot tolerate salicylates. Nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been implicated as a mediator of inflammation. Recent evidence suggests that anti-inflammatory effect of salicylates lies in the inhibition of iNOS, but nothing has been reported about the direct effect of iNOS expression by acetaminophen. The present study was designed to elucidate sequentially the action mechanisms of acetaminophen and salicylates (aspirin and sodium salicylate) on lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma)-induced iNOS expression in RAW 264.7 macrophages. Both acetaminophen and salicylates inhibited NO production and iNOS protein expression in a dose dependent manner. Acetaminophen inhibited iNOS mRNA expression, promoter activity of iNOS gene and nuclear factor-kappa B (NF-kappaB) binding activity induced by LPS plus IFN-gamma, whereas salicylates did not show any effect on them. In addition, salicylates did not affect on iNOS mRNA stability induced by LPS plus IFN-gamma. Furthermore, the inhibition of iNOS protein expression and NO production by salicylates was disappeared when salicylates were added for only 5 h to inhibit the early event of iNOS expression. Aspirin also dose dependently inhibited iNOS enzyme activity in cell-free extracts, whereas no significant differences were observed in extracts treated with sodium salicylate or acetaminophen. These findings suggest that acetaminophen may exert analgesic or anti-inflammatory effect by inhibiting iNOS expression induced by LPS plus IFN-gamma at transcriptional level by suppression of NF-kappaB binding activity, whereas salicylates exert its effect by inhibiting iNOS expression at the translational or posttranslational level.
authors.affiliation: Department of Pharmacology, Chungnam National University, Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Ryu
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: J H
authors.initials: JH
authors.lastname: Seok
authors.forename: J H
authors.initials: JH
authors.lastname: Hong
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee
authors.forename: J H
authors.initials: JH
authors.lastname: Lim
authors.forename: Y M
authors.initials: YM
authors.lastname: Kim
authors.forename: G M
authors.initials: GM
authors.lastname: Hur
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001241:Aspirin / Q000494:pharmacology; D002384:Catalysis / Q000187:drug effects; D002457:Cell Extracts; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012459:Salicylates / Q000494:pharmacology*; D012980:Sodium Salicylate / Q000494:pharmacology
chemical_list: D000893:Anti-Inflammatory Agents; D002457:Cell Extracts; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D012459:Salicylates; D009569:Nitric Oxide; D000082:Acetaminophen; D007371:Interferon-gamma; D004247:DNA; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D001241:Aspirin; D012980:Sodium Salicylate