Cell reorientation under cyclic stretching

TL;DR

This paper introduces a new theoretical framework to understand how cells reorient themselves in response to cyclic stretching, combining experimental data with a dissipative relaxation model to explain cellular mechanosensitivity.

Contribution

The study presents a novel theory that explains cell reorientation under cyclic stretch by modeling dissipative elastic energy relaxation, supported by extensive experimental validation.

Findings

The new theory accurately predicts cell reorientation dynamics.

Existing models are incompatible with experimental data.

Cell reorientation is driven by elastic energy relaxation.

Abstract

Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations -- cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell's passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells, measured over a wide range of experimental conditions, thus elucidating a basic aspect of mechanosensitivity.