Emergent cell migration from cell shape deformations and T1 transitions

TL;DR

This study demonstrates how local cell shape deformations and T1 transitions, despite their random nature, lead to emergent, coordinated cell migration and flow patterns in epithelial tissues.

Contribution

It reveals the correlation between cell shape, T1 transition distribution, and tissue-scale cell migration using multi-phase field and elastic solid models.

Findings

T1 transitions are spatially correlated and shape-dependent.

Cells losing neighbors relax, while those gaining neighbors elongate.

Asymmetric T1 transition patterns promote directed cell migration.

Abstract

T1 transitions, which are localised cell rearrangements, play an important role in the fluidization of epithelial monolayers. Using a multi-phase field model and an active elastic solid model, we show that although each cell undergoes T1 transitions in time as uncorrelated, random events, the spatial distribution of these events is highly correlated and is dependent on cell shape. T1 transitions have a dual effect. Cells losing neighbours tend to relax their shape, while those gaining neighbours tend to elongate. By analysing the statistics of successive T1 transitions undergone by a deformable cell, we find asymmetric spatial distributions related to how cells lose or gain neighbours. These asymmetric spatial patterns of T1 transitions promote directed cell migration, and form the backbone for coherent flow patterns at tissue scales.