Active self-polarization of contractile cells in asymmetrically shaped domains.
Active self-polarization of contractile cells in asymmetrically shaped domains.
复制标题
不对称形状区域中收缩细胞的主动自极化。
DOI：
10.1103/physreve.76.021905
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
S. Safran
中科院分区：
文献类型：
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作者：
A. Zemel;S. Safran
收缩细胞产生的机械力使细胞能够感知环境，并与其他细胞相互作用。通过对环境的局部拉力，细胞可以感知和响应机械特征，如局部应力(或应变)、细胞域的形状和周围的刚性；同时，它们还可以改变系统的机械状态。这就产生了一个机械反馈回路，可以导致细胞的自极化。在这篇文章中，我们提出了一个定量的力学模型，它预测球状结构域中细胞的自极化，球状结构域包括收缩细胞和弹性基质，这些细胞嵌入在三维无细胞凝胶中。该理论是基于对固体中被动夹杂物的已知结果的推广，以包括细胞活动的影响。我们使用Zemel提出的活性细胞磁化率张量[Phys.莱特牧师。97,128103(2006年)]来计算极化响应，从而计算蜂窝域中的细胞所形成的弹性应力场。与无细胞的周围材料相比，细胞极化被分析为细胞区域的形状和弹性模量的函数。与实验一致的是，我们的理论预测，在被一种大的无细胞材料包围的凝胶中，细胞会产生更强的收缩力，这种材料的弹性模量比含有细胞的凝胶更硬。这为在游离凝胶和固定凝胶中观察到的细胞力的发展差异提供了一个定量的解释。在非对称形状(球状)晶胞的情况下，我们证明了晶胞内部的各向异性弹性场导致了沿晶胞长轴的自发自极化。
Mechanical forces generated by contractile cells allow the cells to sense their environment and to interact with other cells. By locally pulling on their environment, cells can sense and respond to mechanical features such as the local stress (or strain), the shape of a cellular domain, and the surrounding rigidity; at the same time, they also modify the mechanical state of the system. This creates a mechanical feedback loop that can result in self-polarization of cells. In this paper, we present a quantitative mechanical model that predicts the self-polarization of cells in spheroidally shaped domains, comprising contractile cells and an elastic matrix, that are embedded in a three-dimensional, cell-free gel. The theory is based on a generalization of the known results for passive inclusions in solids to include the effects of cell activity. We use the active cellular susceptibility tensor presented by Zemel [Phys. Rev. Lett. 97, 128103 (2006)] to calculate the polarization response and hence the elastic stress field developed by the cells in the cellular domain. The cell polarization is analyzed as a function of the shape and the elastic moduli of the cellular domain compared with the cell-free surrounding material. Consistent with experiment, our theory predicts the development of a stronger contractile force for cells in a gel that is surrounded by a large, cell-free material whose elastic modulus is stiffer than that of the gel that contains the cells. This provides a quantitative explanation of the differences in the development of cellular forces as observed in free and fixed gels. In the case of an asymmetrically shaped (spheroidal) domain of cells, we show that the anisotropic elastic field within the domain leads to a spontaneous self-polarization of the cells along the long axis of the domain.