  Collective cell migration in cohesive units is vital for tissue
morphogenesis, wound repair, and immune response. While the fundamental driving
forces for collective cell motion stem from contractile and protrusive
activities of individual cells, it remains unknown how their balance is
optimized to maintain tissue cohesiveness and the fluidity for motion. Here we
present a cell-based computational model for collective cell migration during
wound healing that incorporates mechanochemical coupling of cell motion and
adhesion kinetics with stochastic transformation of active motility forces. We
show that a balance of protrusive motility and actomyosin contractility is
optimized for accelerating the rate of wound repair, which is robust to
variations in cell and substrate mechanical properties. This balance underlies
rapid collective cell motion during wound healing, resulting from a tradeoff
between tension mediated collective cell guidance and active stress relaxation
in the tissue.
