LncRNA H19通过miR449b-Notch1信号调控BMP9诱导的血管形成和成骨分化

阐明BMP9诱导的血管形成机制是构建基于BMP9的组织工程骨需解决的瓶颈问题之一。前期利用新型小RNA库筛选并鉴定出调控BMP9诱导骨形成的关键lncRNA: H19。并发现：①沉默H19导致BMP9诱导的MSCs成骨分化减弱、血管形成受阻，且可被外源性激活Notch1信号补救；②Notch1调控BMP9诱导的成骨分化和血管形成；③MiR449b抑制BMP9诱导的成骨分化和的血管形成。故提出BMP9/H19/miR449b-Notch1信号调控BMP9诱导血管形成进而影响骨形成的假设，即：BMP9调控H19，H19通过CeRNA机制吸附miR449b，并活化Notch1促进血管形成和骨形成。本课题将通过体内外实验证实上述信号轴的存在，以及该信号轴促血管形成和骨形成的分子机制，并在骨缺损模型上明确干预上述通路对BMP9促进的骨缺损修复的影响，为构建基于BMP9的组织工程骨提供理论和实验依据。

Effective bone formation requires a well-coordinated coupling of osteogenesis and blood vessel formation. BMP9 mediated blood vessel formation is essential for BMP9 based bone tissue engineering. Recently, to figure out the regulation effect of long non-coding RNA (lncRNA), we successfully constructed a novel short RNA library, which expresses completely-randomized 19-mer. Through RNA library screening, we identified that lncRNA H19 (H19) was one of the most important lncRNA that regulated BMP9 induced bone formation. Our further research found silencing H19 blocked BMP9 induced bone formation combined with blocked blood vessel formation, which could be rescued by the activation of Notch1. Meanwhile, Notch1 regulated BMP9 mediated blood vessel formation and osteogenesis. In addition, miR449b inhibited BMP9 induced osteogenic differentiation and blood vessel formation of MSCs. Therefore, we deduce that BMP9/H19/miR449b-Notch1 signaling regulates BMP9 mediated blood vessel formation of MSCs and further promotes bone formation. Namely, BMP9 regulates H19 expression, H19 inhibits miR449b through competing endogenous RNA（CeRNA）mechanism, and further promotes blood vessel formation and bone formation through Notch1 signaling. This study will verify the regulation hypothesis of BMP9/H19/miR449b-Notch1 and mechanisms in detail will be clarified through both in vitro and in vivo tests. Furthermore, we will identify the repair effect of BMP9-H19-miR449b mediated tissue engineering bone through nude mice skull bone defect model. Collectively, this project will provide new theoretical and experimental evidence for BMP9 mediated bone tissue engineering.