Rebamipide inhibits tumor necrosis factor-α-induced interleukin-8 expression by suppressing the NF-κB signal pathway in human umbilical vein endothelial cells

Abstract

Objective: This study was designed to identify the inhibitory effect of rebamipide on tumor necrosis factor-α (TNF-α)-induced interleukin-8 (IL-8) production and nuclear factor-κB (NF-κB) activation in human umbilical vein endothelial cells (HUVECs).

Methods: After stimulation with TNF-α, HUVECs were treated with rebamipide in a dose-dependent manner. The viability of HUVECs was assessed using methylthiazol tetrazolium assay after 24 h incubation with rebamipide. TNF-α-induced IL-8 expression was determined by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (RT-PCR). TNF-α-induced IκB-α phosphorylation and translocation of NF-κB p65 subunit into nucleus in endothelial cells were assessed using immunoblot analysis.

Results: We found that rebamipide decreased the expression of IL-8 in the dose-dependent manner under the treatment with TNF-α 10 ng/ml. TNF-α-induced degradation of IκB-α at 15 min was maximally observed and rebamipide (2 mM) inhibited TNF-α-induced phosphorylation of IκB-α in the cytoplasm of endothelial cells by western blot analysis. Rebamipide also suppressed TNF-α-stimulated NF-κB p65 nuclear translocation.

Conclusion: Rebamipide suppresses TNF-α-induced IL-8 production through (1) inhibition of IκB-α phosphorylation in the cytoplasm and (2) blockage of NF-κB p65 protein transport into the nucleus. We suggest that the anti-inflammatory effect of rebamipide is related to the down-regulation of IL-8 expression that is important in endothelial inflammation.