EphrinB2 signaling regulates osteogenesis in periodontal tissue regeneration

Abstract

The study aimed to investigate the effects of ephrinB2 signaling on osteogenesis in periodontal tissue regeneration. In the first study, we investigated the angiogenic and osteogenic capacity and pericyte-like profile of stem cells from human exfoliated deciduous teeth (SHEDs) and dental pulp stem cells (DPSCs). This part investigated the angiogenic and pericyte-like functions of SHEDs and DPSCs. We performed osteogenic and adipogenic assays to evaluate the mesenchymal potential of SHEDs, DPSCs, and pericytes. We conducted an in vitro Matrigel angiogenesis assay to reveal the ability of SHEDs, DPSCs, and pericytes to stabilize vascular-like structures. We conducted quantitative real-time polymerase chain reaction (RT-qPCR) to evaluate mRNA expression. Flow cytometry, western blotting, and immunostaining were used to assess the protein expression. Wound healing and transwell assays were performed to evaluate the migration ability of SHEDs, DPSCs, and pericytes. The osteogenic and adipogenic induction assays showed that SHEDs, DPSCs, and pericytes exhibited similar stem cell characteristics. The mRNA expression levels of PDGFR-β, α-SMA, NG2, and DEMSIN in SHEDs and DPSCs cultured in EC culture medium were significantly higher compared to those in the control groups on day 7 (P < 0.05), and significantly higher than those in the pericytes group on day 14 (P < 0.05). Flow cytometry showed that high proportions of SHEDs and DPSCs were positive for various pericyte markers on day 7. The DPSCs, SHEDs, and pericytes displayed strong migration ability; however, there was no significant difference among the groups (P > 0.05). This first study concluded that SHEDs and DPSCs show a profile similar to that of pericytes. Our study lays a solid theoretical foundation for the clinical use of DPSCs as a potential candidate to replace pericytes. In the second study, we explored the effects of ephrinB2 reverse signaling on osteogenic differentiation of human periodontal ligament stem cells (PDLSCs). We demonstrated that transgenic expression of ephrinB2 in PDLSCs promoted osteogenic differentiation via stimulating the phosphorylation of ephrinB2 and EPHB4, which regulate cell communication between PDLSCs as well as PDLSCs and pre-osteoblasts within coculture. In the third study, we developed endothelial progenitor cells (EPCs)/PDLSCs in three-dimensional (3D) cell sheets using cell membrane technology with a coculture of ephrinB2 over-express canine PDLSCs (cPDLSCs) and EPCs. EPCs/cPDLSCs-ephrinB2 3D cell sheets were wrapped around the implants’ surface before transplanting to the osteoporotic canine mandible. This study indicated that ephrinB2-cPDLSCs/EPC-3D cell sheet promoted alveolar osseointegration on the implant surface. In conclusion, our study demonstrated that ephrinB2 reverse signaling promoted osteogenic differentiation of PDLSCs and alveolar bone repair in beagles, highlighting its therapeutic potential for treating periodontal tissue damage in clinical practice.