Emergence of homeostatic epithelial packing and stress dissipation through divisions oriented along the long cell axis

TLDR

Animal cells undergo dramatic shape changes during mitosis, and in epithelial tissues the orientation of division influences tissue mechanics, yet the cues that orient divisions are poorly understood. The study investigates how mitotic shape changes affect cell packing and stress in stretched monolayers lacking neighbor exchange, using live imaging, mechanical perturbations, and computational modeling. Live imaging, mechanical perturbations, and computational modeling were employed to analyze mitotic shape changes in stretched monolayers without neighbor exchange. They found that divisions align with the long cell axis rather than stress direction, and that this orientation restores cell packing and dissipates stress, underscoring a key role for oriented division in morphogenetically active tissues.

Abstract

Significance Animal cells undergo a remarkable series of shape changes as they pass through mitosis and divide. In an epithelial tissue, the impact of these morphogenetic processes depends strongly on the orientation of division. However, the cues orienting divisions remain poorly understood. Here, we combine live imaging and mechanical perturbations with computational modeling to investigate the effects of shape changes accompanying mitosis and division in stretched monolayers in the absence of neighbor exchange. We show that divisions orient with the long cell axis rather than with the stress direction, and show how oriented divisions contribute to the restoration of cell packing and stress relaxation. In doing so, we identify a clear role for oriented cell division in morphogenetically active tissues.