炎症微环境中长链非编码RNA-MIR31HG调控骨髓间充质干细胞成骨分化的研究

The bone renewal process is usually complicated by inflammatory reaction. Although bone marrow mesenchymal stem cells (BMSCs) is one of the ideal seed cells of tissue engineering for repairing bone loss，the mechanism for the inhibition of BMSC osteoblast differentiation under inflammatory condition remains unclear. Several studies indicated long non-coding RNAs (lncRNAs) are important in BMSC osteogenesis, but whether lncRNAs are involved in inflammatory inhibition of bone formation remains unknown. In this study, we confirmed that lncRNA-MIR31HG was upregulated by the stimulation of inflammatory cytokines. In turn, MIR31HG regulated the NF-κB activity and knockdown of MIR31HG significantly promoted BMSC osteogenic differentiation. Thus, we propose the regulatory circuitry between MIR31HG and NF-κB may affect BMSC osteoblast differentiation under inflammatory condition. This project is conducive to confirm the role of MIR31HG in osteoblast differentiation of BMSCs under inflammatory condition in vitro and in vivo, and determine the molecular mechanism of the regulatory loop between MIR31HG and NF-κB signaling pathway. This project will be helpful to verify the value of lncRNA as effective target molecular for enhancing bone regeneration under inflammatory condition, and will benefit the clinical translation of bone tissue engineering based on BMSCs.

骨缺损修复引起的炎症反应在骨改建中发挥重要作用。虽然骨髓间充质干细胞（BMSCs）是组织工程中修复骨缺损的理想种子细胞之一，但炎症微环境对BMSCs成骨分化的影响及分子机制尚不清楚。已知长链非编码RNA（lncRNA）在干细胞分化中起重要作用，但其在炎症微环境下如何调控干细胞成骨分化尚未见报道。本项目前期研究表明，炎症因子可上调BMSCs中lncRNA-MIR31HG的表达；敲低MIR31HG不仅促进干细胞成骨分化，还同时抑制炎症反应关键通路NF-κB活性。因此，我们推测MIR31HG与NF-κB之间存在相互调控环路，并可能影响炎症环境下干细胞成骨分化。本研究拟通过体外细胞学，分子生物学和动物体内实验，明确MIR31HG在炎症微环境中对BMSCs成骨的影响，并深入阐明MIR31HG与NF-κB间相互调控的分子机制，探索利用lncRNA为药物靶点实现拮抗炎症因子进而高效促进干细胞成骨分化。

骨缺损修复引起的炎症反应在骨改建中发挥重要作用。长链非编码RNA（lncRNA）在干细胞分化中起重要作用，但其在炎症微环境下如何调控干细胞成骨分化尚未见报道。本项目前期研究表明，炎症因子可上调lncRNA-MIR31HG的表达；敲低MIR31HG不仅促进干细胞成骨分化，还同时抑制炎症反应关键通路NF-κB活性。因此，我们推测MIR31HG与NF-κB之间存在相互调控环路，并可能影响炎症环境下干细胞成骨分化。研究结果显示NF-κB的p65亚基通过结合在MIR31HG的上游启动子区调控其表达，而MIR31HG通过结合IκBα影响NF-κB通路的激活。同时，MIR31HG的启动子区存在多个甲基化调控位点，甲基化抑制剂能够促进MIR31HG的表达。此外，MIR31HG通过结合HDAC，对组蛋白乙酰化水平进行调控。本研究通过体外细胞学，分子生物学和动物体内实验，明确了MIR31HG在炎症微环境中对成骨细胞分化的影响，并深入阐明MIR31HG与NF-κB间相互调控的分子机制，阐明了DNA甲基化和机械力对MIR31HG表达的影响，探索了MIR31HG对组蛋白乙酰化的影响，为利用MIR31HG的潜在应用和转化提供理论依据。