外泌体调控ADSCs在ColⅠ/RGD改性n-HAP支架中成骨的效能与机制研究

Artificial bone engineering scaffold material with stem cells and growth factors is a promising solution. Adipose-derived stem cells (ADSCs) are multi-potential stem cells.According to our previous study, we have verified that exosomes can promote the osteogenic differentiation of undifferentiated ADSCs, however the exact mechanism is still unclear.Furthermore, By gene-chip screening, we found that the expression of miR-130a-3p in exosomes, which was extracted during osteogenic differentiation, was most obviously up-regulated compared to control group. On the other hand, we successfully made ColⅠ/ n-HAP scaffolds, but its surface lacks of specific biological signals, affecting the attachment of cells and exosomes to the material.In this study, we are going to solve this problem by adding RGD（Arginine-Glycine-Aspartic Acid）to the material surface as specific biological signal. Furthermore, we will study the key role of miR-130a-3p during exosomes enhance osteogenic differentiation of ADSCs，and explore the mechanism which miR-130a-3p of exosomes actives Wnt signalling pathway to regulate osteogenic differentiation of ADSCs. In addition, we will apply ColⅠ/ RGD-modified n-HAP scaffolds with exosomes and ADSCs to the repair of mandible defect in rabbits, which will provide new ideas and experimental basis for the repair of clinical bone defects.

联合干细胞及生长因子的人工骨组织工程是未来治疗颌骨缺损的希望。脂肪干细胞（Adipose-derived stem cells，ADSCs）具有多向分化潜能，我们已验证其成骨分化时分泌的外泌体能促原始ADSCs成骨，但外泌体诱导ADSCs成骨的机制尚待阐明。我们通过基因芯片检测发现不同分化阶段的ADSCs外泌体中miR-130a-3p表达差异最显著；另外我们已成功制备I型胶原/纳米羟基磷灰石支架材料，但材料表面缺乏特定的生物信号，影响其粘附率。因此，本项目拟在材料上衔接含RGD（Arginine-Glycine-Aspartic Acid）序列的多肽以赋予其生物信号，同时探究miR-130a-3p在外泌体促进ADSCs成骨分化过程中的作用和信号传导机制，并在ColⅠ/RGD改性n-HAP支架上负载外泌体和ADSCs，通过兔下颌骨缺损模型观测骨修复疗效，为临床骨缺损修复提供新思路和基础。

联合干细胞及生长因子的人工骨组织工程是未来治疗颌骨缺损的希望。脂肪干细胞（Adip ose-derived stem cells，ADSCs）具有多向分化潜能，本部分研究通过实验探究，证实了只有来源于经过成骨诱导的脂肪干细胞外泌体才能促进脂肪干细胞的成骨分化，而未经诱导的脂肪干细胞外泌体不能。此外，利用基因芯片（Microarray）技术分析比较了未经诱导脂肪干细胞外泌体和经成骨诱导脂肪干细胞外泌体中miRNAs的表达谱，发现不同分化阶段的ADSCs外泌体中miR-130a-3p表达差异最显著。并进行了相关生物信息学分析，以进一步探讨这些差异表达的miRNAs所影响的生物学功能，同时本研究也阐明了miR-130a-3p/SIRT7/Wnt/β-catenin轴在调控ADSCs成骨分化过程中的重要意义，为骨再生的临床治疗提供了理论依据。另外我们已成功制备I型胶原/纳米羟基磷灰石支架材料，但材料表面缺乏特定的生物信号，影响其粘附率。因此，本项目在材料上衔接含RGD（Arginine-Glycine-Aspartic Acid）序列的多肽以赋予其生物信号，并在ColⅠ/RGD改性n-HAP支架上负载外泌体和ADSCs，通过兔下颌骨缺损模型证实材料具备良好的修复效能，为临床骨缺损修复提供新思路和基础。