| Abstrakt: |
In this study, we examined the effect of extracellular matrix (ECM) components including type I collagen (Col I), type IV collagen (Col IV), laminin, and fibronectin on differentiation of the human osteoblastic cell line SV-HFO when the cells were treated with dexamethasone (Dex), which induces the cells' mineralization. All ECM proteins clearly increased the alkaline phosphatase (ALP) activity of SV-HFO cells in a dose-dependent fashion. Similarly, treatment with 1α, 25-dihydroxyvitamin D (1,25(OH)D) induced the ECM components to enhance the osteocalcin (OC) synthesis of SV-HFO cells. Each ECM component had distinct effects depending on the soluble factor used; with Dex treatment, fibronectin more efficiently increased the ALP activity of Dex-treated SV-HFO cells than Col I, Col IV, or laminin, while with 1,25(OH)D treatment, Col IV more efficiently increased on OC synthesis than the other ECMs. We also examined the expression of integrins, an ECM receptor family, using monoclonal antibodies. Flow cytometric analysis demonstrated that SV-HFO cells expressed all very late antigen (VLA) integrins including VLA-1 to VLA-6 as well as αβ integrin, and that the expression of VLA integrins is regulated by the Dex-induced cell differentiation. These findings suggest that ECM components have soluble factor-dependent stimulatory effects on the regulation of osteoblastic differentiation of SV-HFO cells, possibly through the cell surface ECM receptors in the integrin family. [ABSTRACT FROM AUTHOR] |
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