Expansion and differentiation of periodontal ligament STRO-1⁺/CD146⁺ cells with FGF-2

Objectives: The STRO-1⁺/CD146⁺ cells in human periodontal ligament cells (HPDL cells) have characteristics of stem cells. Although several reports suggested that fibroblast growth factor-2 (FGF-2) played a crucial role in self-renewal of bone marrow mesenchymal stem cells, the effects of FGF-2 on STRO-1⁺/CD146⁺ cells in HPDL cells has not been fully understood. The objective of this study was to expand the STRO-1⁺/CD146⁺ cells in HPDL cells using FGF-2, and examine the characteristics of the STRO-1⁺/CD146⁺ cells. Methods: HPDL cells (n=15) were obtained from extracted teeth using out growth method. The HPDL cells were cultured with or without FGF-2. The percentage of STRO-1⁺/CD146⁺ cells in HPDL cells were analyzed and sorted using FACSAria™. The mRNA expression of various cell specific marker genes in HPDL cells and the sorted STRO-1⁺/CD146⁺ cells was analyzed using RT-PCR. To examine multilineage differentiation potential of the STRO-1⁺/CD146⁺ cells, the cells were cultured in adipogenic or osteogenic induction medium and stained with Oil red O and alizarin red, respectively. Expression of mRNA of the cells was examined using RT-PCR. Results: The percentage of the STRO-1⁺/CD146⁺ cells in HPDL cells cultured with FGF-2 significantly increased compared to that cultured without FGF-2 (p < 0.05 ANOVA with Tukey's test). The number of STRO-1⁺/CD146⁺ cells in HPDL cells cultured with FGF-2 was 15-fold higher than those without FGF-2. The sorted STRO-1⁺/CD146⁺ cells expressed PLAP-1, periostin, S100 A4 and scleraxis mRNA, and they had potential to differentiate into both adipocytes and osteoblasts. Conclusion: Present study suggested that FGF-2 augmented the number of STRO-1⁺/CD146⁺ cells in cultured HPDL cells. Expansion of the HPDL stem cells using FGF-2 can be useful strategy for periodontal regeneration using cell transplantation.