Del Alamo Juan C, Meili Ruedi, Alonso-Latorre Baldomero, Rodríguez-Rodríguez Javier, Aliseda Alberto, Firtel Richard A, Lasheras Juan C
Department of Mechanical and Aerospace Engineering, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
Proc Natl Acad Sci U S A. 2007 Aug 14;104(33):13343-8. doi: 10.1073/pnas.0705815104. Epub 2007 Aug 7.
Cell motility plays an essential role in many biological systems, but precise quantitative knowledge of the biophysical processes involved in cell migration is limited. Better measurements are needed to ultimately build models with predictive capabilities. We present an improved force cytometry method and apply it to the analysis of the dynamics of the chemotactic migration of the amoeboid form of Dictyostelium discoideum. Our explicit calculation of the force field takes into account the finite thickness of the elastic substrate and improves the accuracy and resolution compared with previous methods. This approach enables us to quantitatively study the differences in the mechanics of the migration of wild-type (WT) and mutant cell lines. The time evolution of the strain energy exerted by the migrating cells on their substrate is quasi-periodic and can be used as a simple indicator of the stages of the cell motility cycle. We have found that the mean velocity of migration v and the period of the strain energy T cycle are related through a hyperbolic law v = L/T, where L is a constant step length that remains unchanged in mutants with adhesion or contraction defects. Furthermore, when cells adhere to the substrate, they exert opposing pole forces that are orders of magnitude higher than required to overcome the resistance from their environment.
细胞运动性在许多生物系统中起着至关重要的作用，但对于细胞迁移所涉及的生物物理过程的精确量化知识却很有限。需要更好的测量方法来最终构建具有预测能力的模型。我们提出了一种改进的力细胞术方法，并将其应用于分析盘基网柄菌变形虫状形态趋化迁移的动力学。我们对力场进行的显式计算考虑了弹性基质的有限厚度，与先前的方法相比提高了准确性和分辨率。这种方法使我们能够定量研究野生型（WT）和突变细胞系迁移力学的差异。迁移细胞施加在其基质上的应变能的时间演化是准周期性的，可作为细胞运动周期阶段的一个简单指标。我们发现迁移平均速度v和应变能周期T通过双曲线定律v = L/T相关联，其中L是一个恒定步长，在有黏附或收缩缺陷的突变体中保持不变。此外，当细胞黏附在基质上时，它们会施加相反方向的极向力，这些力比克服其环境阻力所需力高出几个数量级。
