  Collective cell migration underlies important biological processes, such as
embryonic development, wound healing and cancer invasion. While many aspects of
single cell movements are now well established, the mechanisms leading to
displacements of cohesive cell groups are still poorly understood. To elucidate
the emergence of collective migration in mechanosensitive cells, we examine a
self-propelled Voronoi (SPV) model of confluent tissues with an orientational
feedback that aligns a cell's polarization with its local migration velocity.
While shape and motility are known to regulate a density-independent
liquid-solid transition in tissues, we find that aligning interactions
facilitate collective motion and promote solidification. Our model reproduces
the behavior observed in jammed epithelial monolayers, which are unjammed by
the addition of the endocytic protein RAB5A that promotes cell motility by
inducing large scale coherent migratory patterns and local fluidization.
