Collective motion of cells crawling on a substrate: roles of cell shape and contact inhibition

TL;DR

This study models cell crawling and contact inhibition to reveal how cell shape influences collective movement, showing that broader fronts promote migration and density waves emerge at higher cell densities.

Contribution

A minimal mechanical model demonstrating how cell shape and contact inhibition influence collective cell migration and pattern formation.

Findings

Cells with broad fronts migrate coherently without explicit alignment.

Narrow-front cells tend to form immobile colonies.

Density waves propagate against migration direction at higher densities.

Abstract

Contact inhibition plays a crucial role in the motility of cells, the process of wound healing, and the formation of tumors. By mimicking the mechanical motion of calls crawling on a substrate using a pseudopod, we constructed a minimal model for migrating cells which gives rise to contact inhibition of locomotion (CIL) naturally. The model cell consists of two disks, one in the front (a pseudopod) and the other one in the back (cell body), connected by a finitely extensible spring. Despite the simplicity of the model, the cells' collective behavior is highly nontrivial, depending on the shape of cells and whether CIL is enabled or not. Cells with a small front circle (i.e. a narrow pseudopod) form immobile colonies. In contrast, cells with a large front circle (i.e. such as a lamellipodium) exhibit coherent migration without any explicit alignment mechanism being present in the model. This suggests that crawling cells often exhibit broad fronts because it helps them avoid clustering. Upon increasing the density, the cells develop density waves which propagate against the direction of cell migration and finally arrest at higher densities.