Mesenchymal stem cell (MSC)-based cartilage tissue regeneration is a treatment with great potential. How to enhance the MSC chondrogenic differentiation is a key issue involved in cartilage formation. In the present study, we seek to expound the phenotypes and mechanisms of DLX5 in chondrogenic differentiation function in MSCs. Stem cells from apical papilla (SCAPs) were used. The Alcian Blue staining, pellet culture system, and cell transplantation in rabbit knee cartilage defect were used to evaluate the chondrogenic differentiation function of MSCs. Western blot, real-time RT-PCR, and ChIP assays were used to evaluate the molecular mechanisms. DLX5 and HOXC8 expressions were upregulated during chondrogenic differentiation. In vitro results showed that DLX5 and HOXC8 enhanced the expression of chondrogenic markers including collagen II (COL2), collagen V (COL5), and sex-determining region Y box protein 9 (SOX9) and promoted the chondrogenic differentiation and the formation of cartilage clumps in the pellet culture system. Mechanically, DLX5 and HOXC8 formed protein complexes and negatively regulated the LncRNA, LINC01013, via directly binding its promoter. In vivo transplantation experiment showed that DLX5 and HOXC8 could restore the cartilage defect in the rabbit knee model. In addition, knock-down of LINC01013 enhanced the chondrogenic differentiation of SCAPs. In conclusion, DLX5 and HOXC8 enhance the chondrogenic differentiation abilities of SCAPs by negatively regulating LINC01013 in SCAPs, and provided the potential target for promoting cartilage tissue regeneration.

中文翻译：

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DLX5和HOXC8通过LINC01013增强了根尖乳头干细胞的软骨分化潜能。

基于间充质干细胞（MSC）的软骨组织再生是一种具有巨大潜力的治疗方法。如何增强MSC的软骨形成分化是涉及软骨形成的关键问题。在本研究中，我们试图阐明DLX5在MSCs软骨分化功能中的表型和机制。使用了来自根尖乳头（SCAP）的干细胞。用Alcian Blue染色，颗粒培养系统和兔膝关节软骨缺损的细胞移植来评价MSCs的软骨分化功能。蛋白质印迹，实时RT-PCR和ChIP分析用于评估分子机制。在软骨分化过程中，DLX5和HOXC8的表达上调。体外实验结果显示，DLX5和HOXC8增强了包括胶原蛋白II（COL2）在内的软骨标记的表达，胶原蛋白V（COL5）和性别决定区域Y盒蛋白9（SOX9）并促进了颗粒培养系统中的软骨分化和软骨团块的形成。在机械上，DLX5和HOXC8通过直接结合其启动子形成蛋白质复合物，并对LncRNA LINC01013产生负调控。体内移植实验表明，DLX5和HOXC8可以修复兔膝关节软骨缺损。此外，敲除LINC01013可增强SCAP的软骨形成分化。综上所述，DLX5和HOXC8通过负向调节SCAPs中的LINC01013增强SCAPs的软骨分化能力，并为促进软骨组织再生提供了潜在的靶点。决定性别的区域Y盒蛋白9（SOX9），并促进颗粒培养系统中的软骨分化和软骨团块的形成。在机械上，DLX5和HOXC8通过直接结合其启动子形成蛋白质复合物，并对LncRNA LINC01013产生负调控。体内移植实验表明，DLX5和HOXC8可以修复兔膝关节软骨缺损。此外，敲除LINC01013可增强SCAP的软骨形成分化。综上所述，DLX5和HOXC8通过负向调节SCAPs中的LINC01013增强SCAPs的软骨分化能力，并为促进软骨组织再生提供了潜在的靶点。决定性别的区域Y盒蛋白9（SOX9），并促进颗粒培养系统中的软骨分化和软骨团块的形成。在机械上，DLX5和HOXC8通过直接结合其启动子形成蛋白质复合物，并对LncRNA LINC01013产生负调控。体内移植实验表明，DLX5和HOXC8可以修复兔膝关节软骨缺损。此外，敲除LINC01013可增强SCAP的软骨形成分化。综上所述，DLX5和HOXC8通过负向调节SCAPs中的LINC01013增强SCAPs的软骨分化能力，并为促进软骨组织再生提供了潜在的靶点。DLX5和HOXC8形成蛋白质复合物，并通过直接结合其启动子来负调控LncRNA LINC01013。体内移植实验表明，DLX5和HOXC8可以修复兔膝关节模型的软骨缺损。此外，敲除LINC01013可增强SCAP的软骨形成分化。综上所述，DLX5和HOXC8通过负向调节SCAPs中的LINC01013增强SCAPs的软骨分化能力，并为促进软骨组织再生提供了潜在的靶点。DLX5和HOXC8形成蛋白质复合物，并通过直接结合其启动子来负调控LncRNA LINC01013。体内移植实验表明，DLX5和HOXC8可以修复兔膝关节模型的软骨缺损。此外，敲除LINC01013可增强SCAP的软骨形成分化。综上所述，DLX5和HOXC8通过负向调节SCAPs中的LINC01013增强SCAPs的软骨分化能力，并为促进软骨组织再生提供了潜在的靶点。