Deletion of RBPJK in Mesenchymal Stem Cells Enhances Osteogenic Activity by Up-Regulation of BMP Signaling.
Deletion of RBPJK in Mesenchymal Stem Cells Enhances Osteogenic Activity by Up-Regulation of BMP Signaling.
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DOI：
10.1371/journal.pone.0135971
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Dong Y
中科院分区：
文献类型：
--
作者：
Shang X;Luo Z;Wang X;Jaeblon T;Marymont JV;Dong Y
最近，我们在体内和体外都证明了依赖于RBPjk的Notch信号在调节骨髓间充质干细胞(MSC)分化过程中的重要性。在这里，我们进一步进行了RBPJK功能丧失的实验，首次证明了RBPJK缺陷的MSC通过上调BMP信号而显示出增强的分化和成骨作用。在本研究中，我们首先比较了免疫球蛋白kappa J区(RBPJK)缺陷的人骨髓间充质干细胞(MSCs)在正常和重组信号结合蛋白中的自发分化和成骨分化。研究发现，RBPJK在新鲜分离的MSCs中高表达，在自发分化过程中表达下调，在诱导分化的成骨介质中表达更强。在MSCs中缺失RBPJK不仅可以促进细胞的自发分化，而且可以通过增强碱性磷酸酶(ALP)活性、茜素红染色、Runx2、骨桥蛋白(OPN)、I型胶原(COL1a1)的基因表达而显著加速条件培养液诱导的成骨分化。此外，去除RBPJK后，BMP信号反应报告活性和磷酸化Smad1/5/8的表达也显著增加。这些结果表明，抑制MSCs中的Notch信号通过上调BMP信号来促进细胞的成骨分化，而RBPJK缺陷的MSC可能是基于细胞的骨组织工程较好的细胞群。
Recently we have demonstrated the importance of RBPjk-dependent Notch signaling in the regulation of mesenchymal stem cell (MSC) differentiation during skeletogenesis both in vivo and in vitro. Here we further performed RBPJK loss-of-function experiments to demonstrate for the first time that RBPJK deficient MSC shows enhanced differentiation and osteogenesis acts via up-regulation of the BMP signaling. In the present study, we first compared the spontaneous and osteogenic differentiation in normal and recombination signal binding protein for immunoglobulin kappa J region (RBPJK) deficient human bone marrow-derived mesenchymal stem cells (MSCs). It was found that RBPJK highly expressed in fresh isolated MSCs and its expression was progressing down-regulated during spontaneous differentiation and even greater in osteogenic media inducted differentiation. Deletion of RBPJK in MSCs not only enhances cell spontaneous differentiation, but also significantly accelerates condition media inducted osteogenic differentiation by showing enhanced alkaline phosphatase (ALP) activity, Alizarin red staining, gene expression of Runx2, Osteopontin (OPN), Type I collagen (COL1a1) in culture. Additionally, BMP signaling responsive reporter activity and phosphor-smad1/5/8 expression were also significantly increased upon removal of RBPJK in MSCs. These data proved that inhibition of Notch signaling in MSCs promotes cell osteogenic differentiation by up-regulation of BMP signaling, and RBPJK deficient MSC maybe a better cell population for cell-based bone tissue engineering.