Stimulation of differentiation in sodium-dependent vitamin C transporter 2 overexpressing MC3T3-E1 osteoblasts

• Published in: Biochemical and biophysical research communications 2004-05, Vol.317 (4), p.1159-1164
• Main Authors: Wu, Ximei, Itoh, Norio, Taniguchi, Takashi, Hirano, Junko, Nakanishi, Tsuyoshi, Tanaka, Keiichi
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Alkaline Phosphatase - metabolism; Animals; Ascorbic acid; Ascorbic Acid - metabolism; Biological Transport; Calcification, Physiologic - physiology; Cell Differentiation; Collagen - metabolism; Differentiation; Gene Expression Regulation, Developmental; Hydroxyproline - metabolism; Kinetics; MC3T3-E1 cells; Mice; Organic Anion Transporters, Sodium-Dependent - biosynthesis; Organic Anion Transporters, Sodium-Dependent - physiology; Osteoblast; Osteoblasts - cytology; Osteoblasts - metabolism; Osteopontin; Overexpression; Promoter Regions, Genetic; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; RNA, Messenger - biosynthesis; Sialoglycoproteins - biosynthesis; Sialoglycoproteins - genetics; Sodium-Coupled Vitamin C Transporters; Sodium-dependent vitamin C transporter; Symporters - biosynthesis; Symporters - physiology
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2004.03.158

Sodium-dependent vitamin C transporter (SVCT) 2 facilitates reduced ascorbic acid (AA) transport in MC3T3-E1 osteoblasts. Our previous studies suggested that Zn-induced osteoblast differentiation and Ca 2+-, PO 4 3−-stimulated osteopontin (OPN) expression might result from their up-regulation effect on SVCT2 expression and AA uptake. Here, we investigated the role of SVCT2 on osteoblast differentiation by using SVCT2-overexpressing cells. Two clones of SVCT2-introduced cells overexpressed SVCT2 mRNA by 2.8- and 3.1-fold those of control cells, which resulted in obvious increase of AA uptake by 2.1- and 2.4-fold in V max with no change in K m. Alkaline phosphatase activity, hydroxyproline content significantly increased in SVCT2-overexpressing cells, and the induction of OPN mRNA was through up-regulation of OPN promoter activity by SVCT2 overexpression. Moreover, SVCT2-overexpressing cells exhibited more ability to promote mineralization and increase calcium deposition under the stimulation of 5 mM β-glycerophosphate. These findings indicate that SVCT2 stimulates osteoblast differentiation and mineralization.