CML-1 inhibits TNF-α-induced NF-κB activation and adhesion molecule expression in endothelial cells through inhibition of IkBα kinase

Abstract

CML-1 is a purified extract from a mixture of 13 oriental herbs (Achyranthis Radix, Angelicae Gigantis Radix, Cinnamomi Cortex Spissus, Eucommiae Cortex, Glycyrrhizae Radix, Hoelen, Lycii Fructus, Paeoniae Radix, Rehmanniae Radix Preparata and Atractylodis Rhizoma, Zingiberis Rhizoma, Zizyphi Semen, Acori Graminei Rhizoma) that have been widely used for the treatment of inflammatory diseases in Asia. Since our previous study has been shown to have the anti-inflammatory activity of CML-1 in vivo and the upregulation of adhesion molecules in response to numerous inducing factors is associated with inflammation, this study examined the effect of CML-1 on the expression of adhesion molecules induced by TNF-α in cultured human umbilical vein endothelial cells (HUVECs). Preincubation of HUVECs for 20 h with CML-1 (1–100 μg/ml) dose-dependently inhibited TNF-α (10 ng/ml)-induced adhesion of THP-1 monocytic cells, as well as mRNA and protein expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1). CML-1 was also shown to inhibit NK-kB activation induced by TNF-α. Furthermore, CML-1 inhibited TNF-α-induced IkB kinase activation, subsequent degradation of IkBα, and nuclear translocation of NK-kB. Evidence presented in this report demonstrated that CML-1 inhibited the adhesive capacity of HUVEC and the TNF-α-mediated induction of E-selectin, ICAM-1 and VCAM-1 in HUVEC by inhibiting the IkB/NF-kB signaling pathway at the level of IkB kinase, which may explain the ability of CML-1 to suppress inflammation and modulate the immune response.