Odontoblast marker gene expression is enhanced by a CC-chemokine family protein MIP-3α in human mesenchymal stem cells

ObjectiveMacrophage inflammatory protein-3 alpha (MIP-3α) is a major CC-chemokine family protein, which serves as a differentiation factor for mesenchymal cells, including osteoblasts and dental pulp cells. The purpose of this study was to investigate the influence of MIP-3α on human mesenchymal stem cell differentiation in vitro.DesignHuman mesenchymal stem cells were maintained in Dulbecco's modified Eagle's medium in the presence or absence of MIP-3α and the presence or absence of osteogenic factors (dexamethasone, β-glycerophoshate and ascorbic acid). Alkaline phosphatase (ALP) activity was measured, and expression of odontoblast and osteoblast markers were examined by RT-PCR and Western blotting.ResultsMIP-3α alone did not increase ALP activity, as compared to controls. The combination of MIP-3α and osteogenic factors increased ALP activity beyond increases observed with osteogenic factors alone. mRNA expression of the odontoblast marker dspp was only detectable when MIP-3α was added together with osteogenic factors at day 7 in three out of four samples. DSP protein level was increased only in the samples treated with both MIP-3α and osteogenic factors until day 5. In contrast, MIP-3α did not influence levels of the osteoblast markers CBFA1 or BSP.ConclusionsThe present study demonstrated that MIP-3α enhanced gene expression and protein levels of odontoblast-related genes, without affecting levels of the osteogenic proteins CBFA1 or BSP.