Dentin sialophosphoprotein-promoted mineralization and expression of odontogenic genes in adipose-derived stromal cells

Dentin sialophosphoprotein (DSPP) is an extracellular matrix, typically dentin- and bone-specific gene, which plays an important role in dentin mineralization and tooth development. Adipose-derived stromal cells (ADSCs) are considered to contain a group of pluripotent mesenchymal stem cells which are capable of mineralization either in vitro or in vivo. In the present study, we hypothesized that overexpression of DSPP would promote mineralization in ADSCs. Our results showed that infection of DSPP-expressing adenovirus (Ad-DSPP) enhanced expression of genes related to mineralization, such as Cbfa1, Osx, BSP, OCN and DMP1 in ADSCs. Alkaline phosphatase activity was also confirmed in Ad-DSPP-infected ADSCs by cytochemistry and alkaline phosphatase activity assay. Mineralization assay indicated that Ad-DSPP-infected ADSCs were able to form mineralized nodules. Another finding in this study is that early odontogenic marker genes such as Msx1, Msx2, Lhx7 and Pax9 were expressed in DSPP-overexpressed ADSCs. Thus, our results suggested that overexpression of DSPP promoted mineralization of ADSCs, and together with the expression of early odontogenic marker genes, implied that these cells may differentiate into functional odontoblast-like cells. Copyright (C) 2007 S. Karger AG, Basel.