Mechanical feedback in size regulation #

Alexander Erlich, Pierre Recho

12:10 Tuesday in 4Q56.

Part of the Chemo-mechanical couplings in growing tissues session.

Abstract #

The mechanism with which cells measure the dimension of the organ in which they are embedded, and slow down their growth when the final size is reached, is a long standing problem of developmental biology. The role of mechanics in this feedback is thought to be important. Morphoelasticity is a standard continuum framework for modeling growing elastic tissues. However, in this theory, in the absence of additional variables, the feedback between growth and mechanical stress leads to either a collapse or unbounded growth of the tissue, but usually prohibits reaching a finite asymptotic size (‘size control’). In this talk, I will modify this classical setting to include an energetic cost associated with growth, leading to the physical effect of size control. The present model simultaneously provides a qualitatively correct residual stress profile and has a naturally emerging necrotic core, all of which have previously been established experimentally in multicellular spheroids. This is achieved through a local feedback mechanism derived from a thermodynamical framework. The model delivers testable predictions for experimental systems, and could be a step towards the understanding of the role of mechanics in the multifaceted question of how growing organs attain their final size.