Shaping the stress field in cell monolayers via intercellular water flows

Abstract

As open systems, cells significantly change their volumes under mechanical forces. Mechanical forces are ubiquitous in cell monolayers due to cell–cell interactions, cell–substrate interactions, and external mechanical perturbations. Thus, cells in the monolayer will dramatically change their volumes. How cellular volume regulation (i.e. water and ion flows) affects the stress profile of cell monolayer, however, remains elusive. In this work, we develop a theoretical framework to systematically study the coupling mechanism between intercellular water flows and cell stress. Consistently with experimental observations, this model can recapitulate prominent distribution features of internal stress and cell–matrix traction, including the localization of traction force, the build-up of internal cell stress, and the scaling relation between traction force and the size of cell monolayer. More importantly, the model can also predict how intercellular water flow field dictates the profiles of traction and internal stress. We find that a bigger water flow field leads to bigger maximum stress and traction. Likewise, as the water flow field increases, the position corresponding to the maximum stress shifts from monolayer center to monolayer periphery. Together, our study establishes a direct link between intercellular water flows and stress profile in the cell monolayers, which will provide a new strategy to modulate the stress field and stress-related physiological processes in living tissues.