LPS刺激人牙髓干细胞产生的外泌体在牙髓再生中的作用

无干细胞移植的牙髓再生技术由于缺乏牙髓干细胞（dental pulp stem cells,DPSCs）的参与，再生的组织在结构和功能方面仍然达不到理想的目标。外泌体（exosome, EXO）是一种可由多种细胞分泌的纳米级小囊泡，通过传递其携带的蛋白质和核酸等生物活性物质介导细胞间的信息交流，可替代母体细胞发挥生物学作用，与母体细胞相比具有稳定易保存、低免疫原性等优点，发挥的功能作用取决于母体细胞的类型和分泌时的生理状态。本项目将采用LPS在诱导成牙条件下刺激DPSCs，探讨LPS对DPSCs分泌的EXO携带的生物信息所产生的变化和影响，通过在体外研究DPSC-EXO诱导骨髓间充质干细胞成牙本质细胞向分化的作用，动物体内评价DPSC-EXO在牙髓血运重建技术中的应用或与趋化因子SDF-1的协同作用，为DPSC-EXO替代DPSCs用于牙髓再生治疗提供依据。

The dental-pulp like tissue regenerated by tissue engineering without dental pulp stem cells (DPSCs) had been proved existing differences both in structure and function compare with dentin-pulp complex. Exosome (EXO) is the nano-sized extracellular vesicles released by various original cells. It packed with cell-type specific combinations of proteins, lipids, coding, and non-coding RNAs. EXOs play a pivotal role in the cell-to-cell communication process by shuttling active cargoes and could replace the original cells for tissue repairing and regeneration. Compared with original cells, EXO is characterized by low immunogenicity capacity, easy storage and easier manipulate. Exosomes have their own distinct functional properties which depend on the type and physiological or pathological conditions of original cell. This project will isolate EXO from DPSCs cultured under odontogenic conditions with or without lipopolysaccharide. The expression profiling of DPSC-EXO miRNA will be analyzed. The potential of DPSC-EXO to induce odontogenic differentiation of bone marrow mesenchymal stem cells will be evaluated in vitro. We also study the dental pulp regeneration capacity of DPSC-EXO combined with evoking apical bleeding or with implanting SDF-1 in vivo, which supposed to provide evidence for applying DPSC-EXO in dental pulp regeneration instead of DPSCs.