EphrinB2和VEGF协同调控牙髓干细胞促进血管新生的实验研究

项目名称： EphrinB2和VEGF协同调控牙髓干细胞促进血管新生的实验研究

项目编号： No.81470735

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 张成飞

作者单位： 香港大学深圳研究院

项目金额： 73万元

中文摘要： 牙髓再生最简便的方法是将体外工程化的牙髓组织植入根管内，以期获得功能性的牙髓牙本质复合体。然而，植入根管内的组织只能通过根尖孔获得血液供应，远离根尖孔的组织会发生缺氧性坏死。因此，获得快速、充分的血液供应，是牙髓再生的关键。我们的研究已表明，牙髓干细胞能促进和稳定内皮细胞形成的血管网；在缺氧条件下上调VEGF和ephrinB2表达，进一步促进新生血管网的形成。因此，我们推测，牙髓干细胞与血管内皮细胞可能通过ephrinB2和VEGF的协同作用，促进内皮细胞增殖、移动和伸展，形成初级血管网，同时诱导牙髓干细胞分化形成周细胞，使新生血管成熟。我们将探讨牙髓干细胞与血管内皮细胞的相互作用；研究ephrinB2激活与血管新生的关系；探索VEGF和ephrinB2协同作用对血管形成和血管结构的影响，以及可能的调控信号。本项目如获得成功，将对牙髓根尖周病、以及其他缺血性疾病的治疗有明显的指导意义。

中文关键词： 牙髓干细胞；血管内皮细胞；周细胞；EphB4/ephrinB2；血管内皮生长因子

英文摘要： Rapid and overwhelming blood supply is of paramount importance in the survival and integration of high volume engineered tissues following in vivo implantation. The root canal space is encapsulated by dentin in the center of each tooth, with only a single blood supply from its apical end. This anatomical limitation poses even more difficulties for a speedy interconnection with the host vascular system. Therefore, it is absolutely fundamental to develop tissue engineering approaches aimed at accelerating blood vessel network formation and re-connectivity with the host tissues. Our previous study showed that dental pulp stem cells (DPSCs) enhanced tube formation when co-cultured with human umbilical vein endothelial cells (HUVECs), and led to stabilization of the preexisting vessel-like structures formed by HUVECs. It also increased the longevity of these structures. Our further study found that stem cells from apical papilla (SCAPs) increased secretion of hypoxia-inducible-factor-α (HIF-α), VEGF and ephrinB2 under hypoxic condition, which in turn significantly induced more tube formation in co-culture scenario of SCAPs and HUVECs, as they may occur in the implanted prevascularized tissue construct. SCAPs have similar characteristics to DPSCs for its stemness. These findings indicate that co-culture of DPSCs or SCAP swith ECs is a promising strategy for regenerative endodontics. It is rational to hypothesize that VEGF and ephrinB2 cooperatively regulate interactions between DPSCs and HUVECs, by stimulating endothelial cells proliferation, migration and assembly into vascular structures; and in another aspect, inducing DPSCs to differentiate into pericytes to stabilize the newly-formed vasculature. The objectives of the present proposal are to explore the role of VEGF and ephrinB2 in the crosstalk between DPSCs and HUVECs; to study the correlation of ephrinB2 expression and phosphorylation with angiogenesis; and to investigate the cooperative effect of VEGF and ephrinB2 on newly-formed vasculature and the detailed vascular structures. This study for the first time will unravel the role of ephrinB2 and VEGF in angiogenesis and in vivo anastomosis; The new knowledge will bring much needed insight into dentine/pulp regeneration and provide a molecular basis for pharmaceutical therapies acting on ephrinB2 and VEGF signaling, so as to orchestrate pericytes recruitment and assembly for dentine-pulp regeneration.

英文关键词： dental pulp stem cells;endothelial cells;pericyte;EphB4/ephrinB2;VEGF