Laboratory for Multiscale Mechanics and Medical Science, Department of Engineering Mechanics, SVL, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Nano Lett. 2024 Jun 12;24(23):7069-7076. doi: 10.1021/acs.nanolett.4c01636. Epub 2024 May 29.
Local cells can actively create reverse bending (evagination) in invaginated epithelia, which plays a crucial role in the formation of elaborate organisms. However, the precise physical mechanism driving the evagination remains elusive. Here, we present a three-dimensional vertex model, incorporating the intrinsic cell polarity, to explore the complex morphogenesis induced by local mechanical modulations. We find that invaginated tissues can spontaneously generate local reverse bending due to the shift of the apicobasal polarity. Their exact shapes can be analytically determined by the local apicobasal differential tension and the internal stress. Our continuum theory exhibits three regions in a phase diagram controlled by these two parameters, showing curvature transitions from ordered to disordered states. Additionally, we delve into epithelial curvature transition induced by the nucleus repositioning, revealing its active contribution to the apicobasal force generation. The uncovered mechanical principles could potentially guide more studies on epithelial folding in diverse systems.
局部细胞可以主动在凹陷的上皮中产生反向弯曲（外翻），这在复杂生物体的形成中起着至关重要的作用。然而，精确的物理机制仍然难以捉摸。在这里，我们提出了一个三维顶点模型，结合了内在的细胞极性，来探索局部机械调制引起的复杂形态发生。我们发现，由于顶端-基底极性的移动，凹陷的组织可以自发地产生局部反向弯曲。它们的确切形状可以通过局部顶端-基底的差异张力和内部应力来进行分析确定。我们的连续体理论在由这两个参数控制的相图中展示了三个区域，显示出曲率从有序到无序状态的转变。此外，我们还研究了由核重定位引起的上皮曲率转变，揭示了它对顶端-基底力产生的积极贡献。所揭示的力学原理可能为研究不同系统中的上皮折叠提供更多的指导。
