The coordination of cell proliferation and migration in growing tissues is crucial in development and regeneration but remains poorly understood. Here, we find that, while expanding with an edge speed independent of initial conditions, millimeter-scale epithelial monolayers exhibit internal patterns of proliferation and migration that depend not on the current but on the initial tissue size, indicating memory effects. Specifically, the core of large tissues becomes very dense, almost quiescent, and ceases cell-cycle progression. In contrast, initially-smaller tissues develop a local minimum of cell density and a tissue-spanning vortex. To explain vortex formation, we propose an active polar fluid model with a feedback between cell polarization and tissue flow. Taken together, our findings suggest that expanding epithelia decouple their internal and edge regions, which enables robust expansion dynamics despite the presence of size and history-dependent patterns in the tissue interior.
Representative raw datasets for each Figure are available at Zenodo DOI: 10.5281/zenodo.3858845Full raw dataset is hundreds of gigabytes due to the video data and can be provided upon request. Key analysis code provided at our github repository: Github DOI: 10.5281/zenodo.3861843
- Daniel J Cohen
- Ricard Alert
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Jody Rosenblatt, King's College London, United Kingdom
© 2020, Heinrich et al.
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