miR-137调控人脂肪间充质干细胞成骨向分化的作用和机制研究

Human adipose-derived stem cells (hASCs) are one type of the ideal seed cells for bone tissue engineering. Our study group indicate that the genetic and chemical blockade of histone demethylase LSD1 promote the osteogenic differentiation of hASCs. However, upstream factors and related molecules that control the functions of LSD1 are still unknown, impeding the further development of targeted drugs. Recent researches show that some miRNAs regulate the osteogenic differentiation of stem cells, and LSD1 is reported to be the target gene of miR-137. Therefore, identifying whether miR-137 regulate the osteogenesis of hASCs via targeting LSD1 and other related molecules has great significance to develop targeted drugs which promote osteogenesis of these cells in the future. The content of this project contains: 1) to explore the effects of overexpressing and knocking down miR-137 on the osteogenic differentiation of hASCs; 2) to investigate the molecular mechanisms of miR-137 regulating the osteogenesis of hASCs, including LSD1 pathway, other pathways and their reciprocal interactions. Our investigation on the roles of miR-137 in hASCs’ osteogenesis will provide a new target for the gene target-therapy of bone defect and definitively benefit the clinical translation of bone tissue engineering based on hASCs. Our exploration on the mechanisms of miR-137 in hASCs’ osteogenesis will enrich the epigenetic modulatory mechanisms of miRNA on the osteogenesis of stem cells.

人脂肪间充质干细胞（hASCs）是骨组织工程的理想种子细胞之一。本课题组发现基因和化学阻断组蛋白去甲基化酶LSD1促进hASCs成骨分化，但其上游调控因素及相关信号分子尚未明确，制约了靶向药物的进一步开发。现报道多种miRNA调控干细胞成骨向分化，且LSD1为miR-137的靶基因，故明确miR-137是否可通过靶向作用LSD1及其他相关信号分子调控hASCs成骨分化对未来开发促进该细胞成骨的靶向药物有重大意义。项目内容有：探究过表达和敲低miR-137对hASCs体内外成骨分化的作用；探究miR-137调控hASCs成骨的机制（LSD1通路、其他通路及通路间的相互作用关系）。本项目中明确miR-137对hASCs的成骨作用可为骨缺损的靶向基因治疗提供新靶点，有利于实现骨组织工程技术的临床转化；探究miR-137调控hASCs成骨的信号通路可丰富miRNA调控干细胞成骨的表观遗传学机制。

抑制组蛋白去甲基化酶（LSD1）可促进人脂肪间充质干细胞（hASCs）成骨分化，但其上游调控因子及相关调控机制尚未明确。miRNA可调控干细胞成骨分化，且在多种肿瘤细胞系中证实LSD1为miR-137的靶基因，故明确miR-137对LSD1及其他相关信号分子的调控作用以及对hASCs成骨分化的影响，对未来开发促进该细胞成骨的靶向药物有重大意义。本项目主要研究miR-137对hASCs体内外成骨向分化的作用效果及其如何通过由LSD1、NOTCH1-HES1和BMP2-SMAD4通路构成的信号网络完成该生物学调控过程。本研究发现：1）miR-137负向调控hASCs体内外成骨向分化；2）miR-137靶向结合NOTCH1的3′ UTR，从而负向调控NOTCH1、正向调控HES1的表达；3）miR-137正向调控LSD1的表达，负向调控BMP2、SMAD4的表达；4）NOTCH1、BMP2信号均可与LSD1交互负向调控，NOTCH1和BMP2信号交互正向调控，最终miR-137通过NOTCH1/LSD1/BMP2信号网络协同调控hASCs成骨向分化。本项目明确miR-137对hASCs的成骨作用可为骨缺损的靶向治疗提供新的靶点，有利于实现骨组织工程技术的临床转化；探究miR-137调控hASCs成骨的信号通路可丰富miRNA调控干细胞成骨的表观遗传机制。