Ephrin-B2 signaling regulates angiogenesis in dental pulp regeneration. IADR/PER, London, England, July 25-28, 2018.

Abstract

Objectives: To identify the specific role and function of ephrin-B2 in angiogenesis, and develop a new approach to accelerating angiogenesis in pulp regeneration by modulating ephrin-B2 expression in stem cells from apical papilla (SCAPs). Methods: SCAPs were transfected with ephrin-B2 using lentiviral expression vectors. Real-time PCR and western blot were performed to detect vascular endothelial growth factor (VEGF) and ephrin-B2 expression in SCAPs after transfection. Tube formation and Matrigel plug assays were performed to evaluate angiogenic ability of SCAPs after transfection. Results: After transfection, ephrin-B2 mRNA and protein expression in experimental group (ephrin-B2-SCAPs) was significantly higher than that of control group (GFP-SCAPs). MTT assays showed no significant difference in proliferation rate among ephrin-B2-SCAPs, GFP-SCAPs, and WT-SCAPs after 3, 5, 7, 9, 11 d of incubation. Tube formation assay revealed that both the average number of tubules and the total length of tubules in HUVECs cocultured with ephrin-B2-SCAPs group were significantly higher than that of control groups at 4 h. HUVECs cocultured with ephrin-B2-SCAPs under normoxia formed more and longer tubules than HUVECs cocultured with GFP-SCAPs under normoxia at 12 and 24 h. ELISA results showed that the concentration of VEGF in supernatants of the ephrin-B2-SCAPs group was also higher than its concentration in supernatants of the GFP-SCAPs group at each time point (4, 12, 24 h). Vivo experiments showed that more blood vessels were seen in the gel balls of ephrin-B2-SCAPs cocultured with HUVECs, whose gel balls were full of dark red blood vessels. CD31, which is the marker of endothelial cells showed the enlarged blood vessels were formed by HUVECs. Conclusions: Co-transplantation of SCAPs and ECs into root canals may accelerate vasculature formation. Overexpression of ephrin-B2 signaling in SCAPs generates functional neo-capillaries with greater vessel volumes. Ephrin-B2 signaling could be utilized to enhance dental pulp regeneration by virtue of accelerating angiogenesis.