Dynamical theory of active cellular response to external stress
Dynamical theory of active cellular response to external stress
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DOI：
10.1103/physreve.78.031923
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发表时间：
2008-09-01
影响因子：
2.4
通讯作者：
Safran, Samuel A.
中科院分区：
文献类型：
--
作者：
De, Rumi;Safran, Samuel A.
我们提出了一个全面的，理论处理的方向响应的外部应力的活跃，收缩细胞嵌入凝胶状弹性介质。该理论既包括由基质变形产生的力，也包括由应力纤维的内部调节和细胞的局部粘连引起的力。我们计算了弹性偶极子的大小和方向的随时间响应，它表征了细胞施加的主动力，适用于各种情况。对于静态或准静态外部应力，细胞方向平行于应力，而对于高频动态外部应力，细胞方向几乎垂直。本文给出了这些效应的数值计算和解析计算。此外，我们还预测了细胞对缓慢和快速变化的外部应力反应的松弛时间；预测了松弛时间随外加频率变化的几种特征标度。我们还处理了应力纤维和黏附的调节由应变（而不是应力）控制的细胞的情况，并表明细胞取向对基质泊松比的预测依赖性可以区分细胞反应的应变和应力调节。
We present a comprehensive, theoretical treatment of the orientational response to external stress of active, contractile cells embedded in a gel-like elastic medium. The theory includes both the forces that arise from the deformation of the matrix as well as forces due to the internal regulation of the stress fibers and focal adhesions of the cell. We calculate the time-dependent response of both the magnitude and the direction of the elastic dipole that characterizes the active forces exerted by the cell, for various situations. For static or quasistatic external stress, cells orient parallel to the stress while for high frequency dynamic external stress, cells orient nearly perpendicular. Both numerical and analytical calculations of these effects are presented. In addition we predict the relaxation time for the cellular response for both slowly and rapidly varying external stresses; several characteristic scaling regimes for the relaxation time as a function of applied frequency are predicted. We also treat the case of cells for which the regulation of the stress fibers and focal adhesions is controlled by strain (instead of stress) and show that the predicted dependence of the cellular orientation on the Poisson ratio of the matrix can differentiate strain vs stress regulation of cellular response.