Speaker
Description
The 2D vertex model is successful in capturing many phenomena observed in epithelia but does not consider out-of-plane mechanical effects. To understand how 3D effects can be captured in 2D, we introduce a model for a monolayer of columnar cells where the energy includes terms relating to volume, surface area, lateral adhesion and cortical tension. When reduced to a 2D formulation, bulk effects due to volume and surface area introduce coupling between the apical area and perimeter. This coupling is not captured in the standard 2D model and leads to a more complex phenomenology. The reduced 2D model has five independent parameters, each of which can lead to a rigidity transition when varied; these are the target apical perimeter as used in the standard 2D model, as well as parameters controlling the strength of adhesion, cortical line tension, total area tension, and constrictive forces at the apical cortex. This reveals multiple potential mechanisms by which tissues can lose rigidity. We also find a sharp continuous squamous to columnar transition in the fixed volume limit, where a floppy region connects the two rigid states. In the rigid regime, the model shows how lateral crowding in a disordered isolated monolayer can lead to cell elongation towards the monolayer centre.
Bibliography
@article{cowley2025modeling,
title={Modeling bulk mechanical effects in a planar cellular monolayer},
author={Cowley, Natasha and Woolner, Sarah and Jensen, Oliver E},
journal={Physical Review E},
volume={112},
number={5},
pages={054401},
year={2025},
publisher={APS}
}
