Contractile network models for adherent cells

TL;DR

This paper compares different contractile network models for adherent cells, highlighting how active contraction and cable mechanics produce realistic cell shapes and force distributions, enhancing understanding of cell-environment interactions.

Contribution

It introduces and compares passive and active contractile network models, emphasizing the importance of cable mechanics for realistic cell morphology and force sensing.

Findings

Active cable networks produce circular arc cell shapes.

Force distribution is locally determined in active cable models.

Passive networks do not replicate the typical cell morphology.

Abstract

Cells sense the geometry and stiffness of their adhesive environment by active contractility. For strong adhesion to flat substrates, two-dimensional contractile network models can be used to understand how force is distributed throughout the cell. Here we compare the shape and force distribution for different variants of such network models. In contrast to Hookean networks, cable networks reflect the asymmetric response of biopolymers to tension versus compression. For passive networks, contractility is modeled by a reduced resting length of the mechanical links. In actively contracting networks, a constant force couple is introduced into each link in order to model contraction by molecular motors. If combined with fixed adhesion sites, all network models lead to invaginated cell shapes, but only actively contracting cable networks lead to the circular arc morphology typical for strongly adhering cells. In this case, shape and force distribution are determined by local rather than global determinants and thus are suited to endow the cell with a robust sense of its environment. We also discuss non-linear and adaptive linker mechanics as well as the relation to tissue shape.