1D confinement mimicking microvessel geometry controls pericyte shape and motility

Pericytes are mural cells of the microvasculature, characterised by their elongated distinct shape. Pericytes span along the axis of the vessels they adhere to, therefore they experience extreme lateral and longitudinal confinement. Pericyte shape is key for their function during vascular regulation and their spatial distribution is established by cell migration during the embryonic stage and maintained through controlled motility in the adult. However, how pericyte morphology is associated with migration and function remains unknown. We use micropatterns to mimic pericyte adhesion to vessels, and to reproduce in vitro the shapes adopted by pericytes in vivo. We show that lateral confinement controls cell shape and produces in vivo-like phenotype. Modelling the pericyte as an incompressible linear elastic material predicts strain and shape of pericytes as a function of lateral confinement. Pericyte kinetics on both laterally confining lanes, and longitudinally constraining motifs is described by dry friction theory. Pericytes are capable of crossing gaps of different sizes. The percentage of crossings is correctly predicted by the likelihood of a fluctuating system to overcome an energy barrier. Our joint experimental and theoretical approach demonstrates the effect of in vivo-like geometrical confinement on pericyte morphology and migration which is accurately described by dry friction theory.