In Vitro Osteogenic Potential of Human Mesenchymal Stem Cells Is Predicted by Runx2/Sox9 Ratio
In Vitro Osteogenic Potential of Human Mesenchymal Stem Cells Is Predicted by Runx2/Sox9 Ratio
复制标题
DOI：
10.1089/ten.tea.2014.0096
复制
发表时间：
2015-01-01
影响因子：
4.1
通讯作者：
Stoddart, Martin J.
中科院分区：
文献类型：
--
作者：
Loebel, Claudia;Czekanska, Ewa M.;Stoddart, Martin J.
简介：Runx2是研究最多的转录因子之一，在间充质干细胞（MSCs）中表达，并致力于成骨分化。在体内软骨内骨形成过程中，Sox9直接与Runx2相互作用并抑制其活性；然而，Sox9在体外直接成骨中的作用在很大程度上被忽视了。方法：体外培养骨髓来源的人间充质干细胞（hMSCs），分别在对照和添加地塞米松（DEX）的成骨培养基中培养。为了进一步研究Sox9在体外直接成骨中的作用，我们用Sox9 siRNA处理hMSCs。结果：我们发现Sox9是hMSCs体外成骨分化的关键早期指标。成骨诱导导致Sox9基因和蛋白表达在第7天显著降低。用Sox9 siRNA处理hMSCs增强矿化，表明Sox9的下调参与了直接成骨。在没有DEX的情况下，Sox9的siRNA敲低本身并不诱导成骨，这表明仍需要其他因素。结论：对不同年龄和性别的非预选献血者（n=12）的筛查显示，第7天的Runx2/Sox9比值与第28天的Ca-45掺入相关。Sox9下调对体外人间充质干细胞矿化的影响表明，迄今为止，Sox9作为直接成骨的主要调节剂具有前所未有的作用。我们认为Runx2/Sox9比值是一种很有前景的早期体外筛选人间充质干细胞成骨性的方法。
Introduction: Runx2 is one of the most studied transcription factors expressed in mesenchymal stem cells (MSCs) upon their commitment toward an osteogenic differentiation. During endochondral bone formation in vivo, Sox9 directly interacts with Runx2 and represses its activity; however, the role of Sox9 in direct osteogenesis in vitro has been largely overlooked.Methods: Bone marrow-derived human MSCs (hMSCs) were cultured in vitro either in the control or osteogenic medium supplemented with dexamethasone (DEX). To further investigate the role of Sox9 in direct osteogenesis in vitro, hMSCs were treated with Sox9 siRNA.Results: We show here that Sox9 is the key early indicator during in vitro osteogenic differentiation of hMSCs. Osteogenic induction leads to a significant decrease of Sox9 gene and protein expression by day 7. Treatment of hMSCs with Sox9 siRNA enhanced mineralization in vitro, suggesting that downregulation of Sox9 is involved in direct osteogenesis. siRNA knockdown of Sox9 did not in itself induce osteogenesis in the absence of DEX, indicating that other factors are still required.Conclusion: Screening of not preselected donors of different ages and gender (n=12) has shown that the Runx2/Sox9 ratio on day 7 is correlated to the Ca-45 incorporation on day 28. The impact of Sox9 downregulation in the mineralization of human MSCs in vitro indicates a so far unprecedented role of Sox9 as a major regulator of direct osteogenesis. We propose that the Runx2/Sox9 ratio is a promising, early, in vitro screening method for osteogenicity of human MSCs.