RORalpha1 and RORalpha4 suppress TNF-alpha-induced VCAM-1 and ICAM-1 expression in human endothelial cells

Retinoic acid receptor-related orphan receptor-alpha (RORalpha) is a nuclear orphan receptor. Adenovirus-mediated overexpression of RORalpha1 and RORalpha4 suppressed tumor necrosis factor-alpha (TNF-alpha)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) in human umbilical vein endothelial cells. Overexpression of RORalpha1 and RORalpha4 also suppressed TNF-alpha-stimulated translocation of p50 and p65 to the nucleus. In contrast, dominant-negative deletion mutants of RORalpha1 and RORalpha4 failed to suppress the induction of VCAM-1 and ICAM-1 and translocations of p50 and p65. These results suggest that RORalpha1 and RORalpha4 regulate the inflammatory responses via inhibition of the nuclear factor-kappaB signaling pathway in endothelial cells.