Expression and regulation of the nuclear receptor RORα in human vascular cells

Retinoic acid receptor-related orphan receptor alpha (RORalpha) is a member of the nuclear receptor superfamily. Using RT-PCR, RORalpha mRNA was identified in human aortic smooth muscle cells (hASMC), endothelial cells (EC), as well as in human mammary arteries and atherosclerotic plaques. We found a predominant expression of RORalpha1 in hASMC, and RORalpha4 in EC, RORalpha2 and RORalpha3 were not detected. In arteries, RORalpha4 was predominant compared with RORalpha1. In atherosclerotic plaques. RORalpha expression was significantly decreased. In hASMC stimulated with cytokines, RORalpha expression was increased by 2.5-fold. RORalpha mRNA was also significantly increased (similar to2-fold) in hASMC and EC cultured under hypoxia. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.