抑制Hmga2促进小鼠脂肪间充质干细胞成骨分化并加速骨缺损修复

Hmga2 knockdown enhances osteogenic differentiation of adipose-derived mesenchymal stem cells and accelerates bone defect healing in mice

目的探讨高迁移率族蛋白A2(HMGA2)在脂肪间充质干细胞(ADSCs)成骨分化进程中的作用及其在骨缺损修复中的应用。方法通过GEO数据库和Rstudio软件,挖掘出在ADSCs“成脂-成骨”分化平衡中的关键节点因子HMGA2,并通过在线蛋白互作网络分析工具String和绘图软件Cytoscape,绘制HMGA2在成骨分化中的互作关系网络,预测其下游作用靶点。设计Hmga2 siRNA并转染小鼠原代脂肪间充质干细胞(mADSCs),诱导其体外成骨分化,在不同时间点(Day 3,Day 7,Day 14)收集样本,通过碱性磷酸酶染色和茜素红染色评估成骨分化能力,并通过RT-qPCR和Western blotting检测成骨特异性标志物Runt相关转录因子2(RUNX2)、骨桥蛋白(OPN)和骨钙素(OCN)的表达。将敲低Hmga2的mADSCs移植至小鼠不可自愈合颅骨缺损处,术后6周通过μCT扫描、骨组织学染色检测成骨标志物,评价骨缺损修复效果。结果GEO数据库分析结果显示HMGA2在ADSCs成脂分化进程中表达上调。蛋白互作网络分析提示在ADSCs成骨分化中,HMGA2的潜在作用靶点包括SMAD7、CDH1、CDH2、SNAI1、SMAD9、IGF2BP3、ALDH1A1。抑制Hmga2后,mADSCs中成骨分化相关标志物RUNX2、OPN和OCN的表达显著上调,且碱性磷酸酶的表达和钙结节的形成增加(P<0.05)。在小鼠颅骨缺损模型中,敲低Hmga2促进了骨缺损部位的新骨形成(P<0.05)。结论HMGA2是调控ADSCs成骨分化的重要因子,抑制Hmga2能显著促进ADSCs成骨分化,并加速体内骨缺损的修复。

Objective To investigate the role of high-mobility group AT-hook 2(HMGA2)in osteogenic differentiation of adipose-derived mesenchymal stem cells(ADSCs)and the effect of Hmga2 knockdown for promoting bone defect repair.Methods Bioinformatics studies using the GEO database and Rstudio software identified HMGA2 as a key factor in adipogenic-osteogenic differentiation balance of ADSCs.The protein-protein interaction network of HMGA2 in osteogenic differentiation was mapped using String and visualized with Cytoscape to predict the downstream targets of HMGA2.Primary mouse ADSCs(mADSCs)were transfected with Hmga2 siRNA,and the changes in osteogenic differentiation of the cells were evaluated using alkaline phosphatase staining and Alizarin red S staining.The expressions of osteogenic markers Runt-related transcription factor 2(RUNX2),osteopontin(OPN),and osteocalcein(OCN)in the transfected cells were detected using RT-qPCR and Western blotting.In a mouse model of critical-sized calvarial defects,mADSCs with Hmga2-knockdown were transplanted into the defect,and bone repair was evaluated 6 weeks later using micro-CT scanning and histological staining.Results GEO database analysis showed that HMGA2 expression was upregulated during adipogenic differentiation of ADSCs.Protein-protein interaction network analysis suggested that the potential HMGA2 targets in osteogenic differentiation of ADSCs included SMAD7,CDH1,CDH2,SNAI1,SMAD9,IGF2BP3,and ALDH1A1.In mADSCs,Hmga2 knockdown significantly upregulated the expressions of RUNX2,OPN,and OCN and increased cellular alkaline phosphatase activity and calcium deposition.In a critical-sized calvarial defect model,transplantation of mADSCs with Hmga2 knockdown significantly promoted new bone formation.Conclusion HMGA2 is a crucial regulator of osteogenic differentiation in ADSCs,and Hmga2 knockdown significantly promotes osteogenic differentiation of ADSCs and accelerates ADSCs-mediated bone defect repair in mice.