Davallia bilabiata Inhibits TNF-α-Induced Adhesion Molecules and Chemokines by Suppressing IKK/NF-kappa B Pathway in Vascular Endothelial Cells

Abstract

Davallia bilabiata (D. bilabiata) is also called GuSuiBu in Taiwan and is used as a substitute for Drynaria fortunei J. Sm. It is often used for trauma and bone repair. The inhibitory effect of D. bilabiata on inflammatory activity has not been reported. In the present study, we aimed to study the mechanism of anti-inflammation of D. bilabiata on the adhesion of leukocytes to vascular endothelial cells. The results showed that D. bilabiata, at concentrations without cytotoxic effect, inhibited the adhesion of monocytes (THP-1) to the TNF-α-stimulated human umbilical vascular endothelial cells (HUVECs). D. bilabiata suppressed the expression of the adhesion molecules ICAM, VCAM, and E-selectin at both the mRNA and protein level. In addition, both of the TNF-α-induced mRNA and protein expression of chemokines including fractalkine/CX3CL1, MCP-1 and RANTES as well as the level of secreted soluble fractalkine were decreased by D. bilabiata. We also verified that D. bilabiata inhibited the TNF-α-induced nuclear translocation of NF-κB through the inhibitory process on the TNF-α-activated phosphorylation of IKKα, IKKβ, IκB and NF-κB. All together, we concluded that the D. bilabiata affected the canonical pathway of TNF-α-induced NF-κB activation and down-regulated cell adhesion molecules and chemokine expression through inhibition of the NF-κB/IκBα/IKK signaling pathway. These findings strongly indicated that D. bilabiata might be a promising alternative/adjunct treatment for inflammatory diseases, such as rheumatoid arthritis and osteoarthritis.