Dr Andrew Clark

There is growing evidence that the physical properties of the cellular environment can impact cell migration. However, it is not currently understood how active physical remodeling of the network by cells affects their migration dynamics. Here, we study collective migration of small clusters of cells on deformable collagen-1 networks. Combining theory and experiments, we find that cell clusters, despite displaying no apparent internal polarity, generate asymmetric collagen gradients during migration and migrate persistently. We find that persistent migration can arise from viscoelastic relaxation of collagen networks, and reducing the viscoelastic relaxation time by chemical crosslinking leads to a reduction in migration persistence. Single cells produce only short range network deformations that relax on shorter timescales, which leads to lower migration persistence. This simple physical model provides a mechanism for self-generated polarity on viscoelastic substrates during collective migration in the absence of internal biochemical polarity mechanisms.