Tracqui Philippe, Ohayon Jacques
Laboratoire TIMC-IMAG, Equipe DynaCell-CNRS UMR 5525, Institut de l'Ingénierie et de l'Information de Santé, In3S, Faculté de médecine, 38706 La Tronche Cedex, France.
Acta Biotheor. 2004;52(4):323-41. doi: 10.1023/B:ACBI.0000046601.50235.df.
How environmental mechanical forces affect cellular functions is a central problem in cell biology. Theoretical models of cellular biomechanics provide relevant tools for understanding how the contributions of deformable intracellular components and specific adhesion conditions at the cell interface are integrated for determining the overall balance of mechanical forces within the cell. We investigate here the spatial distributions of intracellular stresses when adherent cells are probed by magnetic twisting cytometry. The influence of the cell nucleus stiffness on the simulated nonlinear torque-bead rotation response is analyzed by considering a finite element multi-component cell model in which the cell and its nucleus are considered as different hyperelastic materials. We additionally take into account the mechanical properties of the basal cell cortex, which can be affected by the interaction of the basal cell membrane with the extracellular substrate. In agreement with data obtained on epithelial cells, the simulated behaviour of the cell model relates the hyperelastic response observed at the entire cell scale to the distribution of stresses and strains within the nucleus and the cytoskeleton, up to cell adhesion areas. These results, which indicate how mechanical forces are transmitted at distant points through the cytoskeleton, are compared to recent data imaging the highly localized distribution of intracellular stresses.
环境机械力如何影响细胞功能是细胞生物学中的一个核心问题。细胞生物力学的理论模型为理解可变形的细胞内成分的贡献以及细胞界面处特定的黏附条件如何整合以确定细胞内机械力的整体平衡提供了相关工具。我们在此研究通过磁性扭转细胞术探测贴壁细胞时细胞内应力的空间分布。通过考虑一个有限元多组分细胞模型来分析细胞核刚度对模拟的非线性扭矩 - 磁珠旋转响应的影响，在该模型中细胞及其细胞核被视为不同的超弹性材料。我们还考虑了基底细胞皮层的力学性质，其可能受到基底细胞膜与细胞外基质相互作用的影响。与在上皮细胞上获得的数据一致，细胞模型的模拟行为将在整个细胞尺度上观察到的超弹性响应与细胞核和细胞骨架内直至细胞黏附区域的应力和应变分布联系起来。这些结果表明了机械力如何通过细胞骨架在远处点之间传递，并与最近对细胞内应力高度局部化分布进行成像的数据进行了比较。
