支架材料表面形貌调控Hippo信号在间充质干细胞向成骨细胞分化中的作用和意义

Scffold material is a key elememnt of bone tissue engineering, and the reccent studies demonstrated that the surface topography in nano-scale of scaffold affected the cell behaviors with unclear mechanism.Our previous studie showed that titaniom membrace with 15nm micro-sphere increased the osteogenesis differentiation of mesenchymal stem cells of mouse, and increased the levels of YAP and TAZ,the key factors of Hippo signaling pathway. This Project plans to study the effects and mechnisms of the topography of scaffold on the proliferation and differentiation of mesenchymal stem cells in vitro; the effects and mechanism of BM-MSC cultured in the nano-sphere HA on the healing of cephalic defect in rat; and the effects and mechanism of the increasing of the proliferation and differentiation of mesenchymal stem cells with general culturing based on Hippo signaling.The purposes of this project are to define the effects and mechanism of the nano-topography on the proliferation and osteogenetic differentiation of mesenchymal stem cells, the effects and mechanism of the nano-topography on the proliferation and osteogenetic differentiation of mesenchymal stem cells based on the Hippo signaling pathway. This project is expected to provide a deeper understanding of the mechanism of the nano-topography increasing the proliferation and osteogenetic differentiation of mesenchymal stem cells,and theraic and experimental surport for the desing of the safer and more effective scaffold for bone tissue engineering.

支架材料是组织工程学的一个核心问题，研究发现材料表面的纳米形貌影响干细胞行为，但其信号机制尚不明了。我们的前期研究发现15nm的微球膜能增强小鼠胚胎间充质干细胞的成骨分化，且显著增加细胞内Hippo信号关键因子YAP和TAZ的水平。本项目拟通过在体外细胞模型上研究Hippo信号介导的支架表面纳米形貌调控小鼠胚胎干细胞增殖、分化的效应及机制、纳米微球表面支架上培养的BM-MSC修复小鼠颅骨缺损的效应及机制、以及基于Hippo信号促进普通培养的BM-MSC增殖和成骨分化的效应及机制等的研究，旨在明确支架表面纳米形貌调控间充质干细胞增殖和成骨分化，以及调控Hippo信号的效应和机制，以及纳米形貌通过Hippo信号调控间充质干细胞增殖和成骨分化的意义。本项目研究能深化对支架表面纳米形貌调控细胞分化机制的理解，为设计更为安全有效的骨组织工程支架材料提供理论依据和实验依据。

支架材料是组织工程学的一个核心问题。我们研究发现材料表面的微观形貌能影响干细胞行为，但其信号机制尚不明了。我们设计了10mm*3mm羟基磷灰石支架，采用不同型号的砂纸做表面形貌的打磨（P180，P240，P600，P800，P1200，P2000），对应的颗粒直径分别为82μm，58.5μm，25.8μm，21.8μm，15.3μm，10.3μm。扫描电镜观察可见不同粗细以及深度的打磨痕迹。表面粗糙度扫描检测发现，轮廓算术平均偏差Ra和轮廓微观不平度的平均间距Sm均显示出了打磨颗粒直径一致的变化。以打磨后的材料为支架，骨髓间充质干细胞在打磨后的材料表面显示出了比未打磨的材料上更强的增殖能力；碱性磷酸酶染色和茜素红矿化染色显示打磨后的粗糙表面显著增强了骨髓间充质干细胞的成骨能力；羟基磷灰石支架微米级表面形貌显著增加了骨髓间充质干细胞的成骨基因的表达，且显著增加细胞内Hippo信号关键因子YAP和TAZ的水平，在P600打磨后的材料增加尤其显著。