MKX基因修饰及适配体功能化的尿源性干细胞外泌体靶向调控前交叉韧带塑形的效应及机制研究

肌腱移植重建前交叉韧带(ACL)术后，关节腔内移植物塑形不良(松散、血管化差、甚至吸收)是影响手术疗效的关键因素，其机制不明。我们前期研究发现：塑形不良的移植物胶原合成代谢及MKX基因表达明显下调，而尿源性干细胞外泌体可以减轻缺氧微环境介导的ACL成纤维细胞(ACLFs)线粒体氧化应激损伤，促进ACLFs胶原代谢稳态的维持。因此，我们提出“MKX基因修饰及ACLFs特异性适配体功能化的尿源性干细胞外泌体局部靶向ACLFs调控胶原代谢稳态，促进移植物塑形改建”的科学假说。本研究拟: 1)构建MKX基因修饰及ACLFs特异性适配体功能化的尿源性干细胞外泌体；2)体内外观察新型外泌体在缺氧微环境对ACLFs胶原稳态的调控效应；3)预测并验证新型外泌体调控ACLFs胶原稳态的关键分子及下游靶基因，构建移植物胶原代谢稳态调控的通路网络。本课题的顺利开展将为临床ACL移植物塑形提供新的思路。

The poor remodeling of intra-articular tendon graft (loosening, poor vascularization，resorption, ) after anterior cruciate ligament (ACL) reconstruction is the key factor that affects the outcome of the operation,but the underlying mechanism is not clear. Our previous study found that the collagen anabolism and MKX expression of poorly remodeled graft were significantly down-regulated.The urine-derived stem cell exosomes can diminish the oxidative stress damage to ACL fibroblasts (ACLFs) mitochondria mediated by internal hypoxic microenvironment, which is beneficial to the collagen metabolism homeostasis of ACLFs. Therefore, we hypothesized that MKX gene-modified and ACLFs-specific aptamer-functionalized urine-derived stem cell exosomes would locally take ACLFs as target and regulate the collagen metabolism homeostasis of ACLFs, thus to improve the remodeling outcomes of the tendon graft. In current study,we intend to : 1) construct the MKX gene-modified and ACLFs-specific aptamer-functionalized urine-derived stem cells exosomes; 2)observe the modulation effect of the novel exosomes regulating the collagen metabolism homeostasis of ACLFs under hypoxic microenvironment in vivo and vitro; 3)predict and verify the key biomolecule and downstream target genes and construct the modulation pathway of collagen metabolism homeostasis of graft. The result of the study will provide a new treatment strategy for the poor ACL graft remodeling.