Interfacial friction dictates long-range force propagation in tissues

TL;DR

This study reveals that interfacial friction between tissue layers enables long-range force transmission, with implications for understanding mechanical signaling in tissues.

Contribution

It introduces a theoretical model showing how interlayer friction facilitates force propagation in multilayer tissue systems, supported by experimental validation.

Findings

Long-range wave propagation occurs only with weak interlayer attachment.

Frictional sliding between layers enhances force transmission across tissues.

Substrate stiffness and slipperiness influence wave dynamics.

Abstract

Tissues are characterized by layers of functional units such as cells and extracellular matrix (ECM). Nevertheless, how dynamics at interlayer interfaces help transmit cellular forces in tissues remains overlooked. Here, we investigate a multi-layer system where a layer of epithelial cells is seeded upon an elastic substrate in contact with a hard surface. Our experiments show that, upon a cell extrusion event in the cellular layer, long-range wave propagation emerges in the substrate only when the two substrate layers were weakly attached to each other. We then derive a theoretical model which quantitatively reproduces the wave dynamics and explains how frictional sliding between substrate layers helps propagate cellular forces at a variety of scales, depending on the stiffness, thickness, and slipperiness of the substrate. These results highlight the importance of interfacial friction between layers in transmitting mechanical cues in tissues in vivo.