Synergistic effects of transforming growth factor-β on the expression ofc-fms, macrophage colony-stimulating factor receptor gene, in vascular smooth muscle cells

Abstract

Vascular smooth muscle cells (SMC) transform to foam cells in the process of atherosclerosis. We have reported that SMC derived from the intima of atherosclerotic lesions express c‐fms, macrophage colony‐stimulating factor receptor gene, which is not normally expressed in medial SMC. In the present study, we demonstrated that transforming growth factor‐β (TGF‐β) synergistically induced expression of c‐fms in the presence of platelet‐derived growth factor‐BB in human medial SMC, a level comparable to that observed in the intima. The induction of c‐fms was not inhibited by protein kinase C (PKC) inhibitor, suggesting that TGF‐β induces c‐fms via a PKC‐independent pathway. These results suggest that TGF‐β plays an important role in the phenotypic change of smooth muscle cells to macrophage‐like cells in the process of atherosclerosis.