Abstract

Background: Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, increases the activity of NF-κB (NF-κB) and then induces the expression of intercellular adhesion molecule-1 (ICAM-1). However, the mechanisms regulating ADMA-induced NF-κB activation are unknown. This study investigated the function of actin cytoskeleton for ADMA-induced NF-κB activation and ICAM-1 expression in endothelial cells.
Material/Methods: Human umbilical vein endothelial cells (HUVEC) were cultured and left untreated or challenged for 24h with 100 µM ADMA in the absence and presence of 5 µM cytochalasin D (Cyt D), or 1 µM Jasplakinolide (Jas). The form of actin cytoskeleton, the translocation of NF-κB, NF-κB DNA binding activity, and the expression of ICAM-1 were determined.
Results: ADMA increased the formation of stress fiber in endothelial cells, and Cyt D clearly induced destabilization of the actin filaments. Either stabilizing or destabilizing the actin cytoskeleton prevented ADMA-induced NF-κB activation. It also showed that the inhibition of NF-κB activity was due to the impaired NF-κB nuclear translocation. Further, stabilizing or destabilizing the actin cytoskeleton inhibited the expression of the NF-κB target protein, ICAM-1.
Conclusions: Actin cytoskeleton may be engaged in modulated ADMA-induced NF-κB activation and thereby ICAM-1 expression in endothelial cells.

Keywords: Protein Transport - drug effects, Protein Binding - drug effects, Intercellular Adhesion Molecule-1 - metabolism, Human Umbilical Vein Endothelial Cells - metabolism, Depsipeptides - pharmacology, DNA - metabolism, Cytochalasin D - pharmacology, Cell Nucleus - metabolism, Arginine - pharmacology, Actin Cytoskeleton - metabolism, Stress Fibers - metabolism, Transcription Factor RelA - metabolism