Abstract: Abstract：Objective To investigate the effect of CD24 molecule(CD24) on the osteogenic differentiation potential of stem cells from apical papilla (SCAPs). Methods Lentiviral CD24 ShRNA was used to silence the expression of CD24. Real-time fluorescence quantitative RT-PCR was used to detect the knockout effect of CD24. Alkaline phosphatase (ALP) activity assay was used to detect the ALP activity, which was the early marker of osteogenic differentiation. Alizarin-red staining and calcium quantitative analysis were used to study the potential of SCAPs mineralization in vitro. The expression of osteogenic related genes was detected by real-time fluorescence quantitative RT-PCR, including collagen type I alpha 1 chain (COL1A1), collagen type I alpha 2 chain (COL1A2), bone sialoprotein (BSP), osteonectin (ON) and runt-related transcription factor 2 (RUNX2). The gene expression changes of SCAPs were analyzed. Results Real time RT-PCR result showed that CD24 could be silenced in SCAPs. ALP activity assay showed that the depletion of CD24 inhibited ALP activity. Alizarin-red staining and calcium quantitative analysis revealed that the knockout of CD24 obviously suppressed the mineralization of SCAPs in vitro. Real-time fluorescence quantitative RT-PCR displayed that the depletion of CD24 obviously depressed the expressions of COL1A1, COL1A2, BSP and ON in SCAPs. The RUNX2 expression was repressed in CD24 silenced SCAPs compared with control group. Conclusion The gene silencing of CD24 represses the osteogenic differentiation potential of SCAPs by targeting the RUNX2.

Key words: CD24 molecule (CD24), Stem cells from apical papilla (SCAPs), Osteogenic differentiation