PDGF induces osteoprotegerin expression in vascular smooth muscle cells by multiple signal pathways.

Osteoprotegerin (OPG) is a key regulator of osteoclastogenesis. Recent reports suggest that OPG may function as a protector of arterial calcification and survival of endothelial cells. However, the role and expression of OPG in vascular wall is unclear. Here we report that OPG was highly expressed in vascular smooth muscle cells (VSMC) but not in endothelial cells. Platelet-derived growth factor (PDGF), basic fibroblast growth factor, angiotensin II, tumor necrosis factor alpha and interleukin-1beta upregulated OPG expression in VSMC. Moreover, inhibition of phosphatidylinositol 3-kinase/Akt or P38-signal pathway abrogated PDGF-induced OPG expression. Our results suggest that OPG may be an important determinant of vascular homeostasis.