Conclusions
CD90+ and CD271+ cells are the major components of DPSCs in in vitro culture. High-level expression of HspB8 was critical for maintaining differentiation potential of DPSCs.
Methods
Different passages of rat DPSCs were evaluated for changes in CD90+ and/or CD271+ stem cells and changes in osteogenic potential. Real-time RT-PCR and immunostaining were conducted to determine expression of HspB8 and Gipc2. Expression of the genes in DPSCs was knocked down by siRNA, followed by osteogenic induction to evaluate the function of the genes.
Results
About 90% of cells in the DPSC cultures were CD90+ and/or CD271+ cells without dramatic change during in vitro proliferation. The DPSCs at passages 3 to 5 (P3 to P5) possess strong osteogenic potential, but such potential was greatly reduced at later passages. Expression of HspB8 and Gipc2 was significantly reduced at P11 versus P3. Knock-down of HspB8 expression abolished osteogenic potential of the DPSCs, but knock-down of Gipc2 had no effect. Conclusions: CD90+ and CD271+ cells are the major components of DPSCs in in vitro culture. High-level expression of HspB8 was critical for maintaining differentiation potential of DPSCs.