HIF-1/p53调节乏氧张力下BMSC增殖和成骨分化的特点及与miRNA相关机制研究

The microenvironment that bone marrow derived mesenchymal stem cells (BMSCs) stay is under an oxygen concentration of 2%~7%. BMSCs face severer hypoxia stress when pathological risks present. The stress can recruit local and circulating precursor cells (especially BMSCs) for following reparation. However, the properties of multiplication and osteogenic differentiation that precursor cells possess under severe hypoxia is unclear. Hypoxia inducible factor 1 (HIF-1) is a critical transcription factor which can regulate biological behavior of BMSCs under hypoxia. The effect of hypoxia on BMSCs is dependent on the severity and duration of hypoxia. Moreover, the function of p53 to regulate osteogenic differentiation of BMSCs under hypoxia is closely related to HIF-1. In current research, it aims to explore the characteristics of multiplication and osteogenic differentiation of human BMSCs, and reveal intrinsic relationship between HIF-1 and p53 in controlling multiplication and osteogenic differentiation of BMSCs, as well as differential expressions of microRNA. Furthermore, the expressions of HIF-1 and p53 are regulated through the technique of small interference RNA or enhancer transfection. These reconstructed BMSCs are employed for the treatment of animal model with osteonecrosis of the femoral head, and control groups are set for comparison. The combination of in vitro and in vivo studies is to reveal the individual and reciprocal function of HIF-1/p53 and networks with miRNA, and to better employ BMSCs for cytotherapy in the near future.

骨髓间充质干细胞(BMSC)生存于2%~7%低氧微环境,当病理因素存在时,BMSC 会面临更窘迫的乏氧应激。应激因素常具有募集局部和外周循环中前体细胞(BMSC等)的功能，但募集来的前体细胞如何在此环境中增殖和成骨分化所知甚少。乏氧诱导因子1(HIF-1)是调控乏氧下BMSC细胞周期重要的转录因子；乏氧对 BMSC 增殖的影响与其张力大小有关，并且与乏氧维系时间有关。同时，p53 调控 BMSC 乏氧张力下的分化行为与HIF-1之间关系密切，miRNA在参与构建p53/HIF-1调控网络发挥了重要作用。本研究拟探索乏氧张力下BMSC增殖和成骨分化特点,miRNA差异表达及HIF-1/p53在调控BMSC增殖、分化中的机制，并通过调节HIF-1/p53在BMSC的表达、设计基于基因修饰BMSC治疗骨坏死的动物模型，为阐释BMSC的细胞生物学特点和基于BMSC的临床治疗奠定相关的理论基础。