Mechanochemical Patterning Localizes the Organizer of a Luminal Epithelium

Abstract

The spontaneous emergence of tissue patterns is often attributed to biochemical reaction-diffusion systems. In Hydra tissue regeneration, the formation of a Wnt signaling center serves as a well-known example of such a process. However, despite extensive research, a strictly biochemical mechanism for self-organization in Hydra remains elusive. In this study, we investigated mechanical stimuli and identified a positive feedback loop between Wnt signaling and tissue stretching. We developed a mathematical model of mechanochemical pattern formation in a closed elastic shell, representing regenerating Hydra epithelial spheroids. Our model explains how mechanical forces drive axis formation and predicts the organizer's location under various perturbations, providing a more comprehensive understanding of the spatial dynamics involved. Validation by partially confining regenerating tissues showed that the organizer indeed forms in regions with the greatest stretching potential. This work highlights a novel mechanochemical mechanism for luminal epithelium patterning, suggesting that mechanical forces, in addition to biochemical signals, play a crucial role in tissue regeneration and axis specification. Our findings offer broader implications for the role of mechanical forces in tissue organization in various biological systems, opening new avenues for investigating mechanochemical feedback in development and regeneration.