Abstract :

The directed migration of epithelial cell collectives by coordinated movements is key to many physiological and pathological processes and is often studied at the level of large confluent monolayers. However, many migration processes rely on the migration of small groups of polarized epithelial clusters and their responses to external geometries. At the same time, the development and function of many organisms involve the folding of epithelial monolayers that must adapt to variations of local curvature. Despite their importance on the homeostasis of epithelial systems, spatial confinement and curvature changes are difficult to reproduce, limiting our understanding of these complex mechanisms. In this talk, I will first introduce well-defined in vitro systems based on micropatterned adhesive microstripes to study the migration of small epithelial clusters with well-defined geometries. We will highlight the importance of geometry in defining the migration properties of individual cells and cell clusters, providing a conceptual framework for extracting interaction rules from the way active systems interact with physical boundaries. The second part will introduce a photopolymerization technique using optical photomasks to form wavy hydrogels, allowing us to examine how concave and convex curvatures affect the mechanical properties of epithelial monolayers and induce nuclear deformations. We will show that active cell mechanics and nuclear mechanoadaptation are key players of the mechanistic regulation of epithelia to substrate curvature.

Contact : Martial.Balland@univ-grenoble-alpes.fr