MiRNA-20a promotes osteogenic differentiation of human mesenchymal stem cells by co-regulating BMP signaling
MiRNA-20a promotes osteogenic differentiation of human mesenchymal stem cells by co-regulating BMP signaling
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miRNA-20a通过共同调节BMP信号促进人间充质干细胞的成骨分化
DOI：
10.4161/rna.8.5.16043
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发表时间：
2011-09-01
期刊：
影响因子：
4.1
通讯作者：
Kung, Hsiang-fu
中科院分区：
文献类型：
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作者：
Zhang, Jin-fang;Fu, Wei-ming;Kung, Hsiang-fu
间充质干细胞(MSCs)的成骨分化是一个复杂的过程，受包括microRNAs在内的多种因素的调控。我们的初步数据显示，在成骨分化过程中，内源性miR-20a的表达增加。同时，成骨细胞标志物和调节因子BMP2、BMP4、Runx2、Osx、Ocn和OPn的表达也上调，而脂肪细胞标志物PPARγ和成骨细胞拮抗剂BAMBI和CRIM1表达下调，提示miR-20a在成骨细胞分化调控中起重要作用。为了验证这一假设，我们通过将miR-20a模拟载体和慢病毒miR20a表达载体导入hMSCs来测试其对成骨分化的影响。我们发现miR-20a通过上调BMP/Runx2信号通路促进成骨分化。我们进行了生物信息学分析，预测PPARγ、BAMBI和CRIM1将成为miR-20a的潜在靶点。PPARγ是骨形态发生蛋白/Runx2信号的负调控因子，而BAMBI或CRIM1是骨形态发生蛋白通路的拮抗剂。此外，通过荧光素酶报告、定量RT-PCR和Western印迹分析，我们证实这些分子确实是miR-20a的靶标。与miR-20a过表达类似，特异性siRNA沉默PPARγ、BAMBI或CRIM1可促进成骨。综上所述，我们首次证明miR-20a通过靶向骨形态发生蛋白信号的负调控因子PPARγ、BAMBI和CRIM1，以协同调控的方式促进人MSCs的成骨。
Osteogenic differentiation of mesenchymal stem cells (MSCs) is a complex process, which is regulated by various factors including microRNAs. Our preliminary data showed that the expression of endogenous miR-20a was increased during the course of osteogenic differentiation. Simultaneously, the expression of osteoblast markers and regulators BMP2, BMP4, Runx2, Osx, OCN and OPN was also elevated whereas adipocyte markers PPARγ and osteoblast antagonist, Bambi and Crim1, were downregulated, thereby suggesting that miR-20a plays an important role in regulating osteoblast differentiation. To validate this hypothesis, we tested its effects on osteogenic differentiation by introducing miR-20a mimics and lentiviral-miR20a-expression vectors into hMSCs. We showed that miR-20a promoted osteogenic differentiation by the upregulation of BMP/Runx2 signaling. We performed bioinformatics analysis and predicted that PPARγ, Bambi and Crim1 would be potential targets of miR-20a. PPARγ is a negative regulator of BMP/Runx2 signaling whereas Bambi or Crim1 are antagonists of the BMP pathway. Furthermore, we confirmed that all these molecules were indeed the targets of miR-20a by luciferase reporter, quantitative RT-PCR and western blot assays. Similarly to miR-20a overexpression, the osteogenesis was enhanced by the silence of PPARγ, Bambi or Crim1 by specific siRNAs. Taken together, for the first time, we demonstrated that miR-20a promoted the osteogenesis of hMSCs in a co-regulatory pattern by targeting PPARγ, Bambi and Crim1, the negative regulators of BMP signaling.