DEM, Queen's School of Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom.
LIPhy, CNRS-UMR 5588, Université Grenoble Alpes, F-38000 Grenoble, France.
Phys Rev E. 2018 Jan;97(1-1):012410. doi: 10.1103/PhysRevE.97.012410.
The motility of a cell can be triggered or inhibited not only by an applied force but also by a mechanically neutral force couple. This type of loading, represented by an applied stress and commonly interpreted as either squeezing or stretching, can originate from extrinsic interaction of a cell with its neighbors. To quantify the effect of applied stresses on cell motility we use an analytically transparent one-dimensional model accounting for active myosin contraction and induced actin turnover. We show that stretching can polarize static cells and initiate cell motility while squeezing can symmetrize and arrest moving cells. We show further that sufficiently strong squeezing can lead to the loss of cell integrity. The overall behavior of the system depends on the two dimensionless parameters characterizing internal driving (chemical activity) and external loading (applied stress). We construct a phase diagram in this parameter space distinguishing between static, motile, and collapsed states. The obtained results are relevant for the mechanical understanding of contact inhibition and the epithelial-to-mesenchymal transition.
细胞的运动不仅可以被施加的力触发或抑制，也可以被机械中性力偶触发或抑制。这种加载类型由施加的应力表示，通常被解释为挤压或拉伸，可以来源于细胞与其相邻细胞的外部相互作用。为了量化施加的应力对细胞运动的影响，我们使用了一个分析上透明的一维模型，该模型考虑了活跃的肌球蛋白收缩和诱导的肌动蛋白周转率。我们表明，拉伸可以使静态细胞极化并启动细胞运动，而挤压可以使运动细胞对称化并停止。我们进一步表明，足够强的挤压会导致细胞完整性的丧失。系统的整体行为取决于两个无量纲参数，它们分别描述内部驱动力（化学活性）和外部载荷（施加的应力）。我们在这个参数空间中构建了一个相图，将静态、运动和崩溃状态区分开来。所得结果与接触抑制和上皮-间充质转化的力学理解有关。
