Local shear signals propagate to suppress local cellular motion in stiff epithelia

Abstract

As small particles skim our airways during breathing, or our intestines during digestion, the surface epithelium is subjected to local exogenous shear that deforms hundreds to thousands of tightly interacting cells. Unlike shear deformations applied at the macro-tissue scale or the micro-cell scale, the effects of such perturbations at the meso-scale remain largely unexplored. To address this, we developed a mesoscopic probe that adheres to the apical surface of an epithelial monolayer and applies magnetically derived local shear. We find that localized shear propagated way beyond immediate neighbors and suppressed cellular migratory dynamics in stiffer layers, yet dissipated locally and left dynamics unchanged in softer layers. This mechano-transductive view is reinforced by the observation that stiffening of a soft layer promotes responsiveness to shear. Interpreted within the epithelial jamming framework, shear-induced migratory suppression in stiff layers was accompanied by reduced MSD scaling exponents and changes in cell shape. These changes suggested a localized shift of the tissue toward a lower-energetic state. Together, these observations provide a new perspective on how a local mechanical perturbation traverses the epithelial monolayer to influence both nearby and distant cellular environments.