Aspirin inhibits nuclear factor-kappa B mobilization and monocyte adhesion in stimulated human endothelial cells

The induction of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin by tumor necrosis factor-alpha (TNF) is mediated by mobilization of the transcription factor nuclear factor-kappa B (NF-kappa B). Since salicylates have been reported to inhibit NF-kappa B activation by preventing the degradation of its inhibitor I kappa B, we studied a potential inhibition of this pathway by acetylsalicylate (aspirin) in human umbilical vein endothelial cells (HUVECs).

Gel-shift analyses demonstrated dose-dependent inhibition of TNF-induced NF-kappa B mobilization by aspirin at concentrations ranging from 1 to 10 mmol/L. Induction of VCAM-1 and E-selectin surface expression by TNF was dose-dependently reduced by aspirin over the same range, while induction of intercellular adhesion molecule-1 (ICAM-1) was hardly affected. Aspirin appeared to prevent VCAM-1 transcription, since it dose-dependently inhibited induction of VCAM-1 mRNA by TNF. As a functional consequence, adhesion of U937 monocytes to TNF-stimulated HUVECs was markedly reduced by aspirin due to suppression of VCAM-1 and E-selectin upregulation. These effects of aspirin were not related to the inhibition of cyclooxygenase activity, since indomethacin was ineffective.

Our data suggest that aspirin inhibits NF-kappa B mobilization, induction of VCAM-1 and E-selectin, and subsequent monocyte adhesion in endothelial cells stimulated by TNF, thereby providing an additional mechanism for therapeutic effects of aspirin.