School of Science, Harbin Institute of Technology, Shenzhen, Guangdong, China; Department of Mechanical Engineering, The University of Hong Kong, Pok Fu Lam, Hong Kong; HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Shenzhen, Guangdong, China.
Department of Mechanical Engineering, The University of Hong Kong, Pok Fu Lam, Hong Kong; HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Shenzhen, Guangdong, China; Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong.
Biophys J. 2023 Apr 4;122(7):1315-1324. doi: 10.1016/j.bpj.2023.02.026. Epub 2023 Feb 21.
Although cells with distinct apical areas have been widely observed in epithelial tissues, how the size of cells affects their behavior during tissue deformation and morphogenesis as well as key physical factors modulating such influence remains elusive. Here, we showed that the elongation of cells within the monolayer under anisotropic biaxial stretching increases with their size because the strain released by local cell rearrangement (i.e., T1 transition) is more significant for small cells that possess higher contractility. On the other hand, by incorporating the nucleation, peeling, merging, and breakage dynamics of subcellular stress fibers into classical vertex formulation, we found that stress fibers with orientations predominantly aligned with the main stretching direction will be formed at tricellular junctions, in good agreement with recent experiments. The contractile forces generated by stress fibers help cells to resist imposed stretching, reduce the occurrence of T1 transitions, and, consequently, modulate their size-dependent elongation. Our findings demonstrate that epithelial cells could utilize their size and internal structure to regulate their physical and related biological behaviors. The theoretical framework proposed here can also be extended to investigate the roles of cell geometry and intracellular contraction in processes such as collective cell migration and embryo development.
尽管在上皮组织中广泛观察到具有不同顶区的细胞，但细胞的大小如何影响它们在组织变形和形态发生过程中的行为，以及调节这种影响的关键物理因素仍不清楚。在这里，我们表明，在各向异性双轴拉伸下，单层内细胞的伸长随细胞大小而增加，因为局部细胞重排（即 T1 转变）释放的应变对于具有更高收缩性的小细胞更为显著。另一方面，通过将亚细胞应力纤维的成核、剥离、合并和断裂动力学纳入经典顶点公式，我们发现具有主要与主要拉伸方向一致的取向的应力纤维将在三叉结处形成，这与最近的实验结果一致。应力纤维产生的收缩力有助于细胞抵抗施加的拉伸，减少 T1 转变的发生，从而调节其大小相关的伸长。我们的研究结果表明，上皮细胞可以利用其大小和内部结构来调节它们的物理和相关生物学行为。这里提出的理论框架也可以扩展到研究细胞几何形状和细胞内收缩在细胞集体迁移和胚胎发育等过程中的作用。
