CH6-aptamer/ADK-siRNA联合修饰pDA/PCL/nBG靶向诱导成骨机制的研究

Early recruitment and differentiation of osteoblasts is a key factor in enhancing osteogenic efficiency. Our previous study found that pDA / PCL / nBG scaffolds promote osteoblast recruitment, differentiation and osteogenic targeting. However, the osteogenic quality and efficiency are still not enough. The latest study found that the nucleic acid aptamer (CH6-aptamer) can specifically identify and raise osteoblasts; adenosine kinase (ADK) inhibition of ATP-dependent cell energy metabolism pathway. Therefore, we first proposed to construct a protamine-loaded CH6-aptamer / Protamine / ADK-siRNA complex, then modify it on an existing pDA / PCL / nBG scaffold. After that, we recruit chemotaxis through a combination of complexes and energy activation function to improve the target bone formation efficiency. In this study, based on the analysis of the relationship between osteoblasts and CH6, ADK, the mechanisms of CH6-specific recognition and chemotaxis osteoblast and the specific binding sites were dynamically observed to explore the molecular mechanism of ADK induced osteogenesis. Animal models are used to further reveal the in vivo effect of target-induced osteogenesis. The results not only help to improve the osteogenesis efficiency, but also provide novel ideas for the promotion of maxillofacial bone regeneration.

成骨细胞的早期募集和分化是提高成骨效率的关键因素。课题组前期研究发现，pDA/PCL/nBG支架可促进成骨细胞募集、分化，并增强靶向成骨。但是，其成骨质量和效率仍然不足。最新研究发现，核酸适配体CH6-aptamer能特异性识别和募集成骨细胞；抑制腺苷激酶ADK可激活细胞ATP相关能量代谢通路。据此，我们率先提出，构建鱼精蛋白Protamine为载体的CH6-aptamer/Protamine/ADK-siRNA复合体，将其负载于已有的pDA/PCL/nBG支架，通过联合应用复合体募集趋化作用及能量激活功能，提高靶区成骨效率。本研究拟在分析成骨细胞与CH6、ADK相互关系的基础上，动态观测CH6特异性识别和趋化成骨细胞机制和特异性结合位点，探讨ADK诱导成骨的分子机制。采用动物模型进一步揭示靶向诱导成骨的体内作用效果，研究成果不仅有助于提高成骨效率，也为促进颌面部骨再生提供新思路。

成骨细胞的早期募集和分化是提高成骨效率的关键因素。课题组前期研究发现，PCL/nBG支架可促进成骨细胞募集、分化，并增强靶向成骨。但是，由于成纤维细胞比成骨细胞更具备资源竞争优势，导致成骨质量与效率仍然不足。研究发现，聚多巴胺能够通过希夫反应接枝多种生物活性因子。据此，我们提出，构建PCL/nBG为载体的聚多巴胺壳聚糖复合体支架，通过联合应用复合体募集趋化作用及促成骨功能，提高靶区成骨效率。本研究拟在分析BMSCs与壳聚糖相互关系的基础上，动态观测功能化支架特异性识别和趋化成骨细胞机制和特异性结合位点，探讨壳聚糖诱导成骨的分子机制。采用动物模型进一步揭示靶向诱导体内成骨效果。项目取得的关键数据:项目通过高压成形离子滤沥技术制作的复合支架其压缩模量 ＞8兆帕，优于目前绝大多数传统高分子复合支架，PCL/nBG-PDA-CS支架协同诱导骨及血管再生，细胞增殖能力提高2.5倍，体内成骨能力提高3.61倍。壳聚糖化学锚定的支架表面生物蛋白亲和性更强，化学锚定组缺损内矿化骨组织比壳聚糖物理吸附组以及多巴胺组的密度更高。Micro-CT骨组织定量数据检测显示：多巴胺、壳聚糖分别修饰以及化学锚定组的骨体积分数显著增强。其中，化学锚定组表现出最高的骨小梁体积分数和数量以及最低的骨小梁分离度，进一步提示PCL/nBG-PDA-CS支架能更加有效的提高骨再生。

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