지질다당류에 의해 활성화된 대식세포에서의 4-tert-부틸 페닐 살리실산의 항염증 효과

Abstract

Inflammation may lead to onset of a variety of diseases if it runs uncontrolled. Over-expression of both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins is well known to be crucially related to stimulative effect on some severe chronic inflammatory diseases as well as various tumors. Nuclear factor-κB (NF-κB) is also known to play a critical role in transcriptional regulation of these proteins. This study aims to investigate the anti-inflammatory effect of 4-tert-butyl phenyl salicylic acid (TBPS), one of the salicylic acid derivatives, and to figure out its mechanism by using the model of lipopolysaccharides (LPS)-stimulated Raw 264.7 mouse macrophage cells.

MTT assay, Western blot analysis, ELISA analysis, and Reverse transcription and polymerase chain reaction (RT-PCR) analysis were performed in order to explore the anti-inflammatory effect

of TBPS. It was found that TBPS meaningfully regulated nitric oxide (NO) production without cytotoxic effects on Raw 264.7 cells in a stable state of 1∼15 µg/㎖. TBPS dose-dependently reduced iNOS expression, and COX-2 expression significantly in a range of 1∼15 µg/㎖. Moreover, expressions of iNOS mRNA and COX-2 mRNA meaningfully decreased in a dose dependent manner. In addition, TBPS significantly inhibited the production of inflammatory mediators or pro-inflammatory cytokines such as tumor necrosis factor-a (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Moreover, mRNA gene expressions of TNF-α, IL-1β and IL-6 attenuated in a dose dependent manner.

Furthermore, it was found that TBPS suppressed the LPS-stimulated DNA binding activity of NF-κB. TBPS potently inhibited the translocation of NF-κB into the nucleus by IκBα degradation following IκBα phosphorylation. It indicates that the TBPS inhibits NF-κB activation.

In conclusion, the results show the first that TBPS exerts the anti-inflammatory effect in vitro, both by inhibiting the expressions of iNOS and COX-2 in Raw 264.7 cells, and by suppressing the activation of the NF-κB signaling pathway. Therefore, TBPS may be a potential therapeutic candidate for the regulatory agents of inflammation.