MicroRNA-17-92 cluster 缓释微球组织工程化神经移植物的构建及其应用于修复大鼠周围神经缺损的研究

探索寻找自体神经替代物用以修复周围神经缺损，一直是周围神经再生领域研究热点。本课题组利用经典的大鼠坐骨神经横断模型，不同时间点取近侧和远侧端各0.5cm神经组织进行RNA-seq深度测序，差异表达显著基因基于时序分类，结合mRNA与miRNA表达谱相关性分析，靶基因pathway，整合构建mRNA-miRNA互作网络，结果发现miR-17-92 cluster不仅是发育早期关键调控因子，同时还是周围神经再生过程关键基因。本研究拟运用组织工程研究手段，制备工程化miR-17-92 cluster过表达质粒PLGA缓释微球丝素神经移植物，并将其用于修复大鼠坐骨神经10mm缺损。通过改善局部再生微环境，促进神经元轴突生长，施万细胞增殖迁移，加速血管重建，从而加快神经生长速度，实现靶肌更快更精准重支配，达到神经功能良好恢复。本研究丰富了周围神经再生核心网络调控理论，为开展临床治疗提供新思路新方法。

Tissue engineered nerve grafts (TENGs) represent a promising alternative to autologous nerve grafts used for peripheral nerve repair, and have become a focus in research of peripheral nerve regeneration. In the RNA-seq study with 0.5cm long nerve tissues at different time points from both the proximal and distal nerve ends in the rat sciatic nerve transection model. A set of genes during the process of nerve injury were identified. Most time-dependent differentially expressed genes were functionally classified into different categories. Integrated with the mRNA and miRNA expression profiles, miRNA target gene pathway enrichment analysis, we developed the mRNA-miRNA interaction network to reveal the post-transcriptional landscape of peripheral nerve injury. The results of the bioinformatics analysis indicated that miR-17-92 cluster not only plays a crucial role in neural development, but also the key gene in peripheral neural regeneration. Based on this premise, this project aims to construct a novel TENG that is featured by a controlled release PLGA microsphere drug delivery system through immobilizing a miR-17-92 cluster overexpression plasmid to a silk fibroin-based nerve conduit by using genipin as a crosslinking agent, and to use the TENG for repairing a 10 mm long sciatic nerve defect in rats. Our design is hoped to optimize the regenerative microenvironment by controlling the miR-17-92 cluster expression level, and to promote neurites outgrowth, facilitate Schwann cells proliferation and migration and accelerate vascular remodeling, and thus leading to the better outcome of nerve regeneration, targeted muscle reinnervation and functional recovery. This study provides some new insights into the biological processes and molecular mechanisms underlying peripheral nerve regeneration, and also contributing to the development of a potential therapeutic target for peripheral nerve injury.