Effects of shear stress on germ lineage specification of embryonic stem cells.
Effects of shear stress on germ lineage specification of embryonic stem cells.
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DOI：
10.1039/c2ib20040f
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发表时间：
2012-09
期刊：
影响因子：
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通讯作者：
R. P. Wolfe;Jardin A Leleux;R. Nerem;T. Ahsan
中科院分区：
文献类型：
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作者：
R. P. Wolfe;Jardin A Leleux;R. Nerem;T. Ahsan
迄今为止，机械生物学一直专注于分化的细胞或祖细胞，但机械力对多能干细胞早期分化的影响在很大程度上仍然是未知的。为了研究细胞变形的影响，我们利用流体流动生物反应器施加稳定的层流剪切应力的小鼠胚胎干细胞（ESCs）培养在二维表面上。剪切应力被发现影响多能性，以及中胚层，内胚层和外胚层谱系的胚芽特化，如分别由OCT 4，T-BRACHY，AFP和内斯的基因表达所示。外胚层和中胚层对剪切应力的反应取决于应力大小（范围为1.5至15达因cm（-2））。此外，将持续时间从1天增加到4天导致T-BROCHY持续增加和AFP明显抑制。分化的这些变化与Wnt和雌激素通路的激活同时发生，如通过信号分子的PCR阵列所确定的。总之，这些研究表明，机械微环境可能是一个重要的调节器在早期分化事件，包括原肠胚形成。这一见解进一步了解了发育过程中的正常和病理事件，并促进了扩大临床治疗干细胞生产的策略。
Mechanobiology to date has focused on differentiated cells or progenitors, yet the effects of mechanical forces on early differentiation of pluripotent stem cells are still largely unknown. To study the effects of cellular deformation, we utilize a fluid flow bioreactor to apply steady laminar shear stress to mouse embryonic stem cells (ESCs) cultured on a two dimensional surface. Shear stress was found to affect pluripotency, as well as germ specification to the mesodermal, endodermal, and ectodermal lineages, as indicated by gene expression of OCT4, T-BRACHY, AFP, and NES, respectively. The ectodermal and mesodermal response to shear stress was dependent on stress magnitude (ranging from 1.5 to 15 dynes cm(-2)). Furthermore, increasing the duration from one to four days resulted in a sustained increase in T-BRACHY and a marked suppression of AFP. These changes in differentiation occurred concurrently with the activation of Wnt and estrogen pathways, as determined by PCR arrays for signalling molecules. Together these studies show that the mechanical microenvironment may be an important regulator during early differentiation events, including gastrulation. This insight furthers understanding of normal and pathological events during development, as well as facilitates strategies for scale up production of stem cells for clinical therapies.