Active T1 transitions in cellular networks

Abstract

In amorphous solids as in tissues, neighbor exchanges can relax local stresses and allow the material to flow. In this paper, we use an anisotropic vertex model to study T1 rearrangements in polygonal cellular networks. We consider two different physical realizations of the active anisotropic stresses: (i) anisotropic bond tension and (ii) anisotropic cell stress. Interestingly, the two types of active stress lead to patterns of relative orientation of T1 transitions and cell elongation that are different. Our work suggests that these two realizations of anisotropic active stresses can be observed \textit{in vivo}. We describe and explain these results through the lens of a continuum description of the tissue as an anisotropic active material. We furthermore discuss the energetics of the dynamic tissue and express the energy balance in terms of internal elastic energy, mechanical work, chemical work and heat. This allows us to define active T1 transitions that can perform mechanical work while consuming chemical energy.

Accepted for publication in EPJE. Appendix A with details of the simulations is identical to that in arXiv:2103.16462

References in corpus (6)

• Active wetting of epithelial tissues
• Anisotropy links cell shapes to tissue flow during convergent extension
• Active Fingering Instability in Tissue Spreading
• Effect of cellular rearrangement time delays on the rheology of vertex models for confluent tissues
• Hydraulic and electric control of cell spheroids
• Active instability and nonlinear dynamics of cell-cell junctions

Cited by in corpus (8)

• A Geometric Tension Dynamics Model of Epithelial Convergent Extension
• Shape-tension coupling produces nematic order in an epithelium vertex model
• The role of non-affine deformations in the elastic behavior of the cellular vertex model
• Cell Sorting in an Active Nematic Vertex Model
• Role of intercellular adhesion in modulating tissue fluidity
• Geometry of T1 transitions in epithelia
• Collective epithelial migration mediated by the unbinding of hexatic defects
• Elasticity and plasticity of epithelial gap closure