骨髓间充质干细胞来源外泌体通过力学敏感性lncRNA NR_028591调控骨代谢机制的研究

Disuse osteoporosis caused by stress loss seriously affects the patient's health and quality of life. There is still a lack of effective clinical intervention on disuse osteoporosis and its the pathogenesis is unclear for the present. The regulation of osteogenic differentiation of mesenchymal stem cells (BMSC) and osteoclast differentiation in bone marrow is an essential factor for bone reconstruction. Therefore, it is of great scientific significance to explore new mechanisms of stress stimulation to regulate the osteogenesis and osteoclast differentiation in order to find new targets in the prevention and control of osteoporosis. In our prelimilary studies, we have verified that stress stimulation promoted the osteogenic differentiation of BMSC by regulating the expression of lncRNA NR_028591; the stress stimulation on BMSC also induced the secretion of exosomes with abundant NR_028591, which was phagocyted by the osteoclast precursor, subsequently leading to the inhibition of osteoclast differentiation.The aim of this study is to identify whether stress stimulation induces the osteogenic differentiation of BMSC by regulating the expression of NR_028591, and promotes the secretion of exosomes with abundant NR_028591 from BMSC to mediate intercellular communication and then inhibit osteoclast differerntiation to regulate bone homeostasis.This study would elucidate the mechanism of biomechanical control of intercellular communication in bone remodeling microenvironment in a new perspective, providing research basis and potential therapeutic target for clinical prevention and treatment of disuse osteoporosis.

由于应力缺失导致的废用性骨质疏松症严重影响患者的健康，其发病机制尚不明确，临床上缺乏有效的干预手段。骨髓间充质干细胞（BMSCs）成骨分化以及破骨细胞分化的调控是构建骨重建稳态的要素，探索应力刺激调控成骨和破骨分化的新机制对寻找新的废用性骨质疏松防治靶标有重要科学意义。我们前期研究发现应力刺激通过调控lncRNA NR_028591的表达促进BMSCs的成骨分化。应力刺激BMSCs后可以分泌富含NR_028591的外泌体被破骨前体细胞吞噬并抑制其向破骨细胞分化。因此本课题将研究应力刺激是否通过调控BMSCs中NR_028591表达调控BMSCs的成骨分化，并促进BMSCs释放富含NR_028591的外泌体介导细胞间通讯，抑制破骨细胞分化，调节骨重建稳态并阐述其机制，为阐明骨重建微环境中生物力学调控细胞间通讯机制发掘新研究方向，为临床防治废用性骨质疏松症提供研究基础及潜在药物靶标。

由于应力缺失导致的废用性骨质疏松症严重影响患者的健康，其发病机制尚不明确，临床上缺乏有效的干预手段。骨髓间充质干细胞（BMSCs）成骨分化以及破骨细胞分化的调控是构建骨重建稳态的要素，探索应力刺激调控成骨和破骨分化的新机制以期寻找新的废用性骨质疏松防治靶标有重要科学意义。我们发现在循环机械牵张力学刺激下BMSCs中lncRNA NR_028591的表达显著性升高，lncRNA NR_028591过表达促进BMSCs的成骨分化，敲低lncRNA NR_028591降低BMSCs的成骨分化能力。LncRNA NR_028591通过ceRNA机制调控miR-214的功能促进ATF4的表达从而增强BMSCs的成骨分化能力。BMSCs来源外泌体可以促进破骨前体细胞的凋亡。BMSCs来源外泌体通过抑制破骨前体细胞NF-κB信号通路抑制破骨细胞分化。循环牵张力学刺激条件下BMSCs分泌的外泌体中lncRNA NR_028591的含量显著性升高。过表达lncRNA NR_028591可以显著性降低破骨细胞的分化能力。LncRNA NR_028591通过ceRNA机制调控miR-214的功能促进PTEN的表达从而抑制破骨细胞的分化。BMSCs来源外泌体可以有效促进小鼠骨量的增加。BMSCs来源外泌体可以有效抑制体内破骨细胞分化。利用高通量筛选技术我们筛选出了可以主动促进BMSCs成骨分化的小分子化合物鬼臼毒素和依托泊苷。我们发现鬼臼毒素和依托泊苷可以显著性促进BMSCs的成骨分化。本项目研究结果为废用性骨质疏松的治疗提供了新的治疗靶点和治疗手段。