Maurin B, Cañadas P, Baudriller H, Montcourrier P, Bettache N
Laboratoire de Mécanique et Génie Civil, Université Montpellier 2, UMR CNRS 5508, Montpellier Cedex 5, France.
J Biomech. 2008;41(9):2036-41. doi: 10.1016/j.jbiomech.2008.03.011. Epub 2008 May 7.
The biomechanical behavior of an adherent cell is intimately dependent on its cytoskeleton structure. Several models have been proposed to study this structure taking into account its existing internal forces. However, the structural and geometrical complexities of the cytoskeleton's filamentous networks lead to difficulties for determining a biologically realistic architecture. The objective of this paper is to present a mechanical model, combined with a numerical method, devoted to the form-finding of the cytoskeleton structure (shape and internal forces) when a cell adheres on a substrate. The cell is modeled as a granular medium, using rigid spheres (grains) corresponding to intracellular cross-linking proteins and distant mechanical interactions to reproduce the cytoskeleton filament internal forces. At the initial state (i.e., before adhesion), these interactions are tacit. The adhesion phenomenon is then simulated by considering microtubules growing from the centrosome towards transmembrane integrin-like receptors. The simulated cell shape changes in this process and results in a mechanically equilibrated structure with traction and compression forces, in interaction with the substrate reactions. This leads to a compressive microtubule network and a corresponding tensile actin-filament network. The results provide coherent shape and forces information for developing a mechanical model of the cytoskeleton structure, which can be exploitable in future biomechanical studies of adherent cells.
贴壁细胞的生物力学行为与其细胞骨架结构密切相关。已经提出了几种模型来研究这种结构，并考虑到其现有的内力。然而，细胞骨架丝状网络的结构和几何复杂性导致难以确定生物学上现实的结构。本文的目的是提出一种机械模型，并结合一种数值方法，用于在细胞粘附在基质上时确定细胞骨架结构的形状和内力）。细胞被建模为颗粒介质，使用对应于细胞内交联蛋白的刚性球体（颗粒）和远距离机械相互作用来再现细胞骨架细丝的内力。在初始状态（即粘附之前），这些相互作用是隐性的。然后通过考虑从中心体向跨膜整合素样受体生长的微管来模拟粘附现象。在此过程中，模拟的细胞形状发生变化，并导致与底物反应相互作用的具有牵引力和压缩力的机械平衡结构。这导致压缩微管网络和相应的拉伸肌动蛋白丝网络。这些结果为开发细胞骨架结构的机械模型提供了连贯的形状和力信息，可用于未来贴壁细胞的生物力学研究。
