基于miR-100-5p/mTOR信号通路探讨hUCMSCs来源外泌体对牙髓损伤修复的作用及机制

由于缺乏靶向修复牙髓损伤的盖髓材料，常规牙髓切断术保存活髓的疗效并不理想。我们前期的研究结果提示脐带间充质干细胞来源的外泌体（hUCMSC-Exo）有可能在牙髓组织损伤修复中发挥重要作用。本项目围绕hUCMSC-Exo及其富集表达的miR-100-5p在牙髓损伤修复过程中的作用及相关分子机制展开以下研究：提取hUCMSCs外泌体，观察外泌体及其携带miR-100-5p对牙髓干细胞生物学功能的作用；在牙髓干细胞中对miR-100-5p/mTOR靶向作用的功能相关性进行验证；结合测序结果发现外泌体中存在的其它具有促进损伤修复和再生功能的miRNAs；在动物体内评估水凝胶包封miR-100-5p功能化的hUCMSC-Exo作为盖髓剂的疗效。预期结果将为深入挖掘外泌体的治疗机制提供切入点，为hUCMSC-Exo作为靶向修复牙髓损伤的盖髓材料提供理论依据。

The clinical outcome of conventional pulpotomy for preserving pulp vitality is very uncertain due to lack of targeted restorative materials aimed at biological processes of pulpal inflammation/repair. Our previous study has indicated that human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) may play an important role in pulpal wound healing. In this project, we investigate the effects and related molecular mechanisms of hUCMSC-Exos and exosomal miR-100-5p which is highly expressed in LPS-preconditioned hUCMSC-Exos in repairing pulp damage. The main research contents are as follows: Firstly, we investigate the in vitro effects of hUCMSC-Exos and exosomal miR-100-5p on biological functions of dental pulp stem cells (DPSCs), and combine results with sRNA sequencing to find other exosomal miRNAs that might involve in wound repair and tissue regeneration.We also perform loss- and gain-of-function experiments, rescue experiments, AGO2-RIP assays to verify miR-100-5p directly targets mTOR/NF-κB/p38MAPK activation and modulates downstream inflammatory factors expression. Finally, we assess the in vivo effects of miR-100-5p functionalized hUCMSC-Exos encapsulated in hydrogel as pulp capping agent in animal models.The expected results will shed new light on the mechanisms of hUCMSC-Exos as a new generation of targeted dental restorative material and may provide an effective and accurate strategy for vital pulp therapy.