miR-455-5p靶向Jak2-Stat3通路调控巨噬细胞极化在腱骨愈合的作用及分子机制研究

腱骨愈合不良是韧带重建术后亟待解决的难题。我们发现腱骨愈合早期M1/M2巨噬细胞比例失衡是导致其发生的关键因素（Am J Sports Med 2019），但其调控机制尚不明确。miRNA芯片筛查提示miR-455-5p在腱骨界面组织来源的巨噬细胞中表达显著上调。过表达或沉默miR-455-5p可显著影响巨噬细胞M1/M2表型转换。基因表达谱（miR-455-5p KO vs正常巨噬细胞）、GO及KEGG分析提示Jak2-Stat3通路显著富集，推测miR-455-5p可能靶向Jak2-Stat3通路，促进巨噬细胞 M2极化，进而影响腱骨愈合进程。为验证上述假说，本项目拟采用LysM-CreERT2;miR-455-5pflox/flox与miR-455-5p CKI小鼠模型，探究miR-455-5p调控巨噬细胞极化在腱骨愈合中的分子机制，为促进腱骨愈合提供新的理论依据及治疗靶点。

Poor tendon-to-bone healing is one of the urgent clinical problems to be solved. Our previous studies showed that excessive inflammation caused by M1/M2 imbalance contributes to poor tendon-to-bone healing (Am J Sports Med 2019; NSFC81672159). However, the precise molecular mechanism underlying it remains unclear. miRNA array results reveal that miR-455-5p is significantly upregulated in macrophages from tendon-bone tissue compared with controls. Gain-of-function and loss-of-function studies indicate that miR-455-5p significantly affect macrophages phenotype. Gene expression profile, GO and KEGG analysis demonstrate the enrichment of Jak2-Stat3 pathway. Based on the results, we presume that miR-455-5p may positively regulate Jak2-Stat3 pathway and thus activate it, promoting M2 macrophage polarization, which influences the process of tendon-to-bone healing. In order to validate the hypothesis, the relationship among miR-455-5p, macrophage polarization and Jak2-Stat3 is investigated. The LysM-CreERT2;miR-455-5pflox/flox and miR-455-5p CKI mice, RNAi, CoIP, and mass spectrometry were employed to clarify the key role of miR-455-5p regulating macrophage polarization in tendon-to-bone healing, providing a new theoretical basis and therapeutic strategy for tendon-bone healing after ligament reconstruction.