Systematic profiling of spatiotemporal tissue and cellular stiffness in the developing brain
Systematic profiling of spatiotemporal tissue and cellular stiffness in the developing brain
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DOI：
10.1242/dev.109637
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发表时间：
2014-10-01
期刊：
影响因子：
4.6
通讯作者：
Kosodo, Yoichi
中科院分区：
文献类型：
--
作者：
Iwashita, Misato;Kataoka, Noriyuki;Kosodo, Yoichi
越来越多的证据表明，生态位的物理特性在影响干细胞的行为、生长和分化方面具有重要意义。在物理性质中，细胞外硬度已被证明对几种细胞类型的体外命运决定有直接影响。然而，很少有证据表明，在组织发育过程中，硬度的变化是否发生在体内。为了解决这个问题，我们提出了一个系统的策略来评估刚度的转变，在一个发展组织使用小鼠胚胎大脑皮层作为实验模型。我们将组织和细胞硬度的原子力显微镜测量与特定神经分化标记物的免疫染色相结合，将硬度值与发育中的大脑组织和细胞的特征相关联。我们发现，在发育过程中，脑室和脑室下区的硬度逐渐增加。在E16.5处，中间区域出现了组织刚度峰值。尽管神经元的细胞刚度随着微管细胞骨架的成熟而单调增加，但皮质板的刚度在E18.5时呈初始增加后下降的趋势。这些结果表明，组织刚度不能仅仅由构成组织的细胞的刚度决定。综上所述，我们的方法描述了具有明确特征的活组织和细胞的刚度，因此可以用来进一步理解刚度作为决定大脑皮层和其他组织形成过程中细胞命运的物理因素的作用。
Accumulating evidence implicates the significance of the physical properties of the niche in influencing the behavior, growth and differentiation of stem cells. Among the physical properties, extracellular stiffness has been shown to have direct effects on fate determination in several cell types in vitro. However, little evidence exists concerning whether shifts in stiffness occur in vivo during tissue development. To address this question, we present a systematic strategy to evaluate the shift in stiffness in a developing tissue using the mouse embryonic cerebral cortex as an experimental model. We combined atomic force microscopy measurements of tissue and cellular stiffness with immunostaining of specific markers of neural differentiation to correlate the value of stiffness with the characteristic features of tissues and cells in the developing brain. We found that the stiffness of the ventricular and subventricular zones increases gradually during development. Furthermore, a peak in tissue stiffness appeared in the intermediate zone at E16.5. The stiffness of the cortical plate showed an initial increase but decreased at E18.5, although the cellular stiffness of neurons monotonically increased in association with the maturation of the microtubule cytoskeleton. These results indicate that tissue stiffness cannot be solely determined by the stiffness of the cells that constitute the tissue. Taken together, our method profiles the stiffness of living tissue and cells with defined characteristics and can therefore be utilized to further understand the role of stiffness as a physical factor that determines cell fate during the formation of the cerebral cortex and other tissues.