Mechanical instabilities in expanding epithelia. Elastic waves in a viscous medium?

Datum

11.11.2015

Zeit

11:00 - 12:00

Sprecher

Jaume Casademunt

Zugehörigkeit

University of Barcelona, Spain

Sprache

en

Hauptthema

Biologie

Andere Themen

Biologie

Host

Jan Brugues

Beschreibung

Collective cell migration in freely spreading epithelia in controlled environments has become a landmark in our current understanding of fundamental biophysical processes in development, regeneration, wound healing or cancer. The possibility of measuring simultaneously both local forces and velocities in model epithelial monolayers in vitro, has revealed a rich repertoire of dynamic behavior that is now amenable to quantitative modeling but which remains poorly understood. In particular, some experiments have reported the puzzling observation of apparently elastic waves when one would expect a fluid-like behaviour of the tissue. Here we propose a continuum description that combines two sources of activity: traction forces on the substrate and contractile stresses. This provides a theoretical framework of epithelial monolayers that reveals new mechanical instabilities of polarized tissues generated by active stresses. This explains a variety of experimental observations and in particular the generation of elastic-like waves in a viscous fluid by the presence of active traction forces. We discuss the mechanisms of the different instabilities that lead to pattern formation and traveling waves, and we speculate on the explanation of the 'weakly turbulent' behavior observed in extended epithelia as a transition to spatio-temporal chaos.

Letztmalig verändert: 12.11.2015, 14:16:38