Epithelial layer fluidization by curvature-induced unjamming

TL;DR

This study explores how surface curvature influences epithelial tissue fluidization and cell migration, revealing that increased curvature facilitates the unjamming transition, affecting tissue flexibility and mobility.

Contribution

It introduces a vertex model on a spherical surface to demonstrate the impact of curvature on epithelial unjamming, a factor previously overlooked in flat tissue models.

Findings

Higher curvature reduces energy barriers for cell rearrangements.

Increased curvature enhances cell mobility and intercalation.

Small structures are more migratory, larger ones become rigid.

Abstract

The transition of an epithelial layer from a stationary, quiescent state to a highly migratory, dynamic state is required for wound healing, development, and regeneration. This transition, known as the unjamming transition (UJT), is responsible for epithelial fluidization and collective migration. Previous theoretical models have primarily focused on the UJT in flat epithelial layers, neglecting the effects of strong surface curvature characteristic of the epithelium \textit{in vivo}. In this study, we investigate the role of surface curvature on tissue plasticity and cellular migration using a vertex model embedded on a spherical surface. Our findings reveal that increasing curvature promotes the UJT by reducing the energy barriers to cellular rearrangements. Higher curvature favors cell intercalation, mobility, and self-diffusivity, resulting in epithelial structures that are malleable and migratory when small, but become more rigid and stationary as they grow. Together, these results provide a conceptual framework to better understand how cell shape, cell propulsion, and tissue geometry contribute to tissue malleability, remodeling, and stabilization.