Effect of a Cyclooxygenase-2 Inhibitor on Interleukin-1β–Stimulated Activation of the Transcription Factor Nuclear Factor-Kappa B in Human Gingival Fibroblasts

• Autores: David A. Tipton
• Localización: Journal of periodontology, ISSN 0022-3492, Vol. 78, Nº. 3, 2007, págs. 542-549
• Idioma: inglés
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• Resumen

  • Background: In previous work, the cyclooxygenase-2 inhibitor NS-398 inhibited interleukin (IL)-1β–stimulated prostaglandin E2 (PGE2) production almost completely while partially inhibiting IL-6 production in aggressive periodontitis (AgP) human gingival fibroblasts. PGE2 and the transcription factor nuclear factor-kappa B (NF-κB) regulate IL-1β–stimulated IL-6 production. Cytoplasmic NF-κB is bound to inhibitors (IκB proteins). IL-1β initiates a cascade resulting in phosphorylation and degradation of IκB, allowing nuclear translocation of NF-κB and target gene activation. The purpose of this study was to determine whether NS-398 inhibited phosphorylation of IκB and NF-κB activation.

    Methods: AgP fibroblasts (1 to 2 × 106) were exposed to IL-1β (1 × 10−11M) with or without NS-398 (10 nM) in serum-free medium. The NF-κB subunit p65 and phospho-IκBα were measured in whole cell, cytoplasmic, or nuclear extracts, using colorimetric assays. Enzyme-linked immunosorbent assays were used to measure PGE2 and IL-6 production by 2.5 × 104 cells after exposure to IL-1β with or without NS-398 in serum-free medium.

    Results: Consistent with previous results, NS-398 reduced IL-1β–stimulated PGE2 by ∼98% (P <0.001) and IL-6 by ∼65% (P <0.001). IL-1β increased nuclear and cytoplasmic p65 (∼8-fold [P <0.001] and ∼2.5-fold [P <0.03], respectively) over control levels. NS-398 reduced IL-1β–stimulated nuclear and cytoplasmic p65 to control levels. IL-1β increased phospho-IκBα in whole cell extracts by a maximum of approximately 9.5 times (P = 0.0001), and this was inhibited significantly by NS-398 (P ≤0.008).

    Conclusions: NS-398 inhibited NF-κB activation and nuclear p65 levels in human gingival fibroblasts. This seemed to be due to inhibition of the phosphorylation cascade resulting in formation of phospho-IκBα and free p65. NF-κB inhibition may be useful in treating inflammatory diseases such as AgP.