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Séminaire « Matière molle : organisation et dynamique » de l’INSP

Confined and shaped monolayers - Pascal Silberzan - Vendredi 8 janvier 2016 à 11 h

INSP - 4 place Jussieu - 75252 PARIS Cedex 05 - Barre 22-32 - 4e étage, salle 407

Pascal Silberzan - Centre de Recherche, Institut Curie, Paris

Abstract

Cell monolayers routinely exhibit collective behaviors largely controlled by cell-cell interactions. In this context, confinement and boundary conditions play an important role in the organization and dynamics of these cell assemblies. Interestingly, many in vivo processes, including morphogenesis or tumor maturation, involve small populations of cells within a spatially restricted region. We report experiments in which epithelial monolayers confined in circular disks exhibit low-frequency periodic radial displacement modes. When the boundary is removed, cells collectively migrate on the free surface. The essential characteristics of the collective dynamics in these two situations are well accounted for by the same theoretical model in which cells are described as persistent random walkers which adapt their motion to that of their neighbors. In contrast, elongated fibroblasts that do not develop cell-cell adhesions self-organize until reaching a perfect nematic order upon confinement. After days in culture, the confined epithelia develop a tridimensional structure in the form of a peripheral cell cord at the domain edge. Confinement by itself is therefore sufficient to induce morphogenetic-like processes including spontaneous collective pulsations, global orientation and transition from 2D to 3D. Finally, culturing cell monolayers on cylindrical wires reveals some specific traits of the out-of-plane curvature on the dynamics and architecture of epithelia, independent on the lateral confinement.