Fibroblast growth factor-2 induces osteogenic differentiation through a Runx2 activation in vascular smooth muscle cells

• Published in: Biochemical and biophysical research communications 2010-04, Vol.394 (2), p.243-248
• Main Authors: Nakahara, Takehiro, Sato, Hiroko, Shimizu, Takehisa, Tanaka, Toru, Matsui, Hiroki, Kawai-Kowase, Keiko, Sato, Mahito, Iso, Tatsuya, Arai, Masashi, Kurabayashi, Masahiko
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Animals; ARTERIOSCLEROSIS; Atherosclerosis; Atherosclerosis - genetics; Atherosclerosis - metabolism; Cell Differentiation; Cells, Cultured; Core Binding Factor Alpha 1 Subunit - genetics; Core Binding Factor Alpha 1 Subunit - metabolism; CORONARIES; CYSTEINE; DNA; Fibroblast Growth Factor 2 - pharmacology; Fibroblast Growth Factor 2 - physiology; FIBROBLASTS; FLUORESCENCE; Gene Expression; Gene Knockdown Techniques; Genetic Markers; GROWTH FACTORS; Humans; HYDROGEN PEROXIDE; Hydrogen Peroxide - metabolism; LUCIFERASE; Mitogen-Activated Protein Kinase Kinases - metabolism; Muscle, Smooth, Vascular - cytology; Muscle, Smooth, Vascular - metabolism; MUSCLES; Myocytes, Smooth Muscle - cytology; Myocytes, Smooth Muscle - metabolism; Osteoblasts - metabolism; Osteogenesis; Osteogenic differentiation; Osteopontin - genetics; Protein-Tyrosine Kinases - metabolism; RATS; Receptor, Fibroblast Growth Factor, Type 1 - metabolism; RECEPTORS; Signaling mechanism; SKELETON; src-Family Kinases; TRANSCRIPTION FACTORS; Transcriptional Activation; Vascular calcification; Vascular smooth muscle cells
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2009.11.038

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.