miR-210通过促进骨组织血管生成防治绝经后骨质疏松

Postmenopausal osteoporosis has been associated with decreased ability of bone angiogenesis and osteoblasts differentiation of bone marrow mesenchymal stem cells (BMSCs). Over-expression microRNA-210(miR-210) in normoxic endothelial cells stimulate the formation of capillary-like structures as well as vascular endothelial growth factor (VEGF)-driven cell migration，VEGF is also an important regulator of BMSCs fate, determining whether differentiation gives rise to osteoblasts or adipocytes. We have found that the expression of miR-210 is detected in bone marrow mesenchymal stem cells culture in vitro and miR-210 can promote the expression of vascular edothelial growth factor in bone marrow mesenchymal stem cells. Therefore, this study first aims to demonstrate miR-210 can promote osteoblasts differentiation and inhibit adipocytes differentiation of bone marrow mesenchymal stem cells in vitro and elucidate the regulatory mechanism. Then, bone marrow mesenchymal stem cells transfected with lentivirus-mediated miR-210 in vitro transplant into ovariectomized rats and study the bone angiogenesis, bone quality and bone marrow fat content to demonstrate miR-210 can prevent postmenopausal osteoporosis by promoting bone angiogenesis. This study will be expand a new idea of prevention postmenopausal osteoporosis and provide a theory basis for developing new treatment method of targeting miR-210.

绝经后骨质疏松发病过程中伴随着骨组织血管生成能力的下降和骨髓间充质干细胞（BMSCs）成骨分化能力的降低。内皮细胞微小RNA-210（miR-210）的过表达能刺激毛细血管样结构的形成以及血管内皮生长因子（VEGF）诱导的细胞迁移，VEGF能调控BMSCs分化为成骨细胞还是脂肪细胞。课题组前期研究发现：BMSCs体外培养中检测到miR-210的表达，miR-210能够促进大鼠BMSCs中VEGF的表达。本课题拟首先从细胞水平上证实miR-210能够促进BMSCs成骨分化而抑制其成脂分化，然后将体外慢病毒转染miR-210的BMSCs移植到卵巢切除大鼠体内，研究骨组织血管生成、骨质量和骨髓内脂肪含量的变化，从整体水平上证实miR-210能够通过促进骨组织血管生成防治绝经后骨质疏松。本项目将有助于开拓绝经后骨质疏松防治的新思路，并为开发以miR-210为靶点的治疗方法提供理论基础。

本研究旨在探讨miR-210通过促进骨组织血管生成防治绝经后骨质疏松的作用，研究结果显示：体外培养的大鼠骨髓间充质干细胞（BMSC）中存在miR-210的表达，miR-210模拟物以时间依赖的方式促进了血管内皮生长因子（VEGF）的表达，过表达miR-210的BMSC能显著抑制PPARγ的表达，同时能明显促进ALP和osterix的表达，说明miR-210能促进BMSC的成骨性分化抑制成脂性分化。将体外构建的miR-210和siRNA miR-210慢病毒表达系统感染BMSCs，将细胞悬液通过尾静脉分别注入正常大鼠体内，检测两组大鼠骨组织血管和骨质量的差异，结果表明：与siRNA miR-210组相比，miR-210组大鼠股骨髁血管灌注数量多，VEGF和CD31免疫组化阳性细胞数量多，成骨细胞数量多，而破骨细胞数量少，说明miR-210促进了BMSC的成骨分化而抑制了破骨分化，miR-210组大鼠股骨的最大应力、弹性模量和刚度指标均优于siRNA miR-210组。在卵巢切除（OVX）术后1、2、4周分别通过尾静脉注射转染miR-210和siRNA miR-210的BMSCs，miR-210组大鼠股骨髁血管灌注数量多，VEGF和CD31免疫组化阳性细胞数量多。miR-210组OVX大鼠骨质量明显优于siRNA miR-210组，miR-210组大鼠股骨的最大应力、弹性模量和刚度指标均优于siRNA miR-210组。本研究结果从细胞水平上证实了miR-210能够促进BMSCs 成骨分化而抑制其成脂分化，从整体水平上证实了miR-210 能够通过促进骨组织血管生成防治绝经后骨质疏松。本研究开拓了绝经后骨质疏松防治的新思路，并为开发以miR-210 为靶点的治疗方法提供了理论基础。