Quantifying active and resistive stresses in adherent cells

TL;DR

This paper compares three methods for calculating intracellular stresses in adherent cells, revealing that they measure different stress components and proposing a way to isolate active stress.

Contribution

It demonstrates through 3D FEM modeling that existing methods measure different stress components and suggests combining them to isolate active stress.

Findings

Different methods measure different stress components

Active and resistive stresses are distinguishable

Combining methods can isolate active stress

Abstract

To understand cell migration, it is crucial to gain knowledge on how cells exert and integrate forces on/from their environment. A quantity of prime interest for biophysicists interested in cell movements modeling is the intracellular stresses. Up to now, three different methods have been proposed to calculate it, they are all in the regime of the thin plate approximation. Two are based on solving the mechanical equilibrium equation inside the cell material (Monolayer Stress Microscopy, and Bayesian Inference Stress Microscopy) and one is based on the continuity of displacement at the cell/substrate interface (Intracellular Stress Microscopy). We show here using 3D FEM modeling that these techniques do not calculate the same quantities (as was previously assumed), the first techniques calculate the sum of the active and resistive stresses within the cell, whereas the last one only calculate the resistive component. Combining these techniques should in principle permit to get access to the active stress alone.