Sylvain Gabriele, University of Mons<\/em><\/p>\n The directed migration of epithelial cell collectives through coordinated movements is fundamental to numerous physiological and pathological processes. While these dynamics are often studied in large, confluent monolayers, many migration phenomena involve the movement of small, polarized epithelial clusters and their interactions with external geometries. Additionally, epithelial monolayers must adapt to variations in local curvature during processes like tissue folding and morphogenesis, which are critical for development and homeostasis. Despite their significance, spatial confinement and curvature-induced adaptations remain poorly understood due to challenges in reproducing these conditions in vitro. We will first introduce a photopolymerization technique using optical photomasks to fabricate wavy hydrogels, allowing precise exploration of how concave and convex curvatures influence the mechanical properties of epithelial monolayers and induce nuclear deformations. Our findings highlight the pivotal roles of active cellular mechanics and nuclear mechano adaptation in regulating epithelial responses to substrate curvature. In the second part, we will employ well-defined in vitro systems based on micropatterned adhesive stripes to examine the migration of individual cells and small epithelial clusters with controlled geometries. We will demonstrate the critical role of geometry in defining the migration behaviors of cells and clusters, offering a framework to uncover the rules governing their interactions with physical boundaries. Notably, we will present evidence that migrating cells retain a \u00abmechanical memory\u00bb of past morphological states, enabling enhanced navigation through confined environments. This long-term memory of confinement, mediated by actin cortex remodeling, provides new insights into how cells adapt to dynamic microenvironments and navigate complex spaces.<\/p>\n