Fibroblast Growth Factor 2 Induces Osteogenic Differentiation through a Runx2 Activation in Vascular Smooth Muscle Cells.
Fibroblast Growth Factor 2 Induces Osteogenic Differentiation through a Runx2 Activation in Vascular Smooth Muscle Cells.
Biochem Biophys Res Commun. 2009 Nov 7;
Authors: Nakahara T, Sato H, Shimizu T, Tanaka T, Matsui H, Kawai-Kowase K, Sato M, Iso T, Arai M, Kurabayashi M
Expression of bone-associated proteins and osteoblastic transcription factor Runx2 in arterial cells has been implicated in the development of vascular calcification. However, the signaling upstream of the Runx2-mediated activation of osteoblastic program in vascular smooth muscle cells (VSMC) is poorly understood. We examined the effects of fibroblast growth factor 2 (FGF-2), an important regulator of bone formation, on osteoblastic differentiation of VSMC. Stimulation of cultured rat aortic SMC (RASMC) with FGF-2 induced the expression of the osteoblastic markers osteopontin (OPN) and osteocalcin. Luciferase assays showed that FGF-2 induced osteocyte-specific element (OSE)-dependent transcription. Downregulation of Runx2 by siRNA repressed the basal and FGF-2-stimulated expression of the OPN gene in RASMC. FGF-2 produced hydrogen peroxide in RASMC, as evaluated by fluorescent probe. Induction of OPN expression by FGF-2 was inhibited not only by PD98059 (MEK1 inhibitor) and PP1 (c-Src inhibitor), but also by an antioxidant, N-acetyl cysteine. Nuclear extracts from FGF-2-treated RASMC exhibited increased DNA-binding of Runx2 to its target sequence. Immunohistochemistry of human coronary atherectomy specimens and calcified aortic tissues showed that expression of FGF receptor-1 and Runx2 was colocalized. In conclusion, these results suggest that FGF-2 plays a role in inducing osteoblastic differentiation of VSMC by activating Runx2 through mitogen-activated protein kinase (MAPK)- dependent- and oxidative stress-sensitive signaling pathways.
PMID: 19903460 [PubMed - as supplied by publisher]
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