Cells alter their mechanical properties in response to their local microenvironment; this plays a role in determining cell function and can even influence stem cell fate. Here, we identify a robust and unified relationship between cell stiffness and cell volume. As a cell spreads on a substrate, its volume decreases, while its stiffness concomitantly increases. We find that both cortical and cytoplasmic cell stiffness scale with volume for numerous perturbations, including varying substrate stiffness, cell spread area, and external osmotic pressure. The reduction of cell volume is a result of water efflux, which leads to a corresponding increase in intracellular molecular crowding. Furthermore, we find that changes in cell volume, and hence stiffness, alter stem-cell differentiation, regardless of the method by which these are induced. These observations reveal a surprising, previously unidentified relationship between cell stiffness and cell volume that strongly influences cell biology.

中文翻译：

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通过水流出改变细胞体积会影响细胞刚度和干细胞命运

细胞响应其局部微环境而改变其机械性能；这在决定细胞功能中起着重要作用，甚至可以影响干细胞的命运。在这里，我们确定了细胞刚度和细胞体积之间的稳健和统一的关系。随着细胞在基底上扩散，其体积减小，而其刚度随之增大。我们发现皮层和细胞质的细胞硬度随体积变化而变化，包括许多不同的底物硬度，细胞扩散面积和外部渗透压。细胞体积的减少是水流出的结果，这导致细胞内分子拥挤的相应增加。此外，我们发现细胞体积的变化以及因此的硬度都会改变干细胞的分化，而与诱导这些细胞的方法无关。