Geometry-driven migration efficiency of minimal cell clusters
The directed migration of epithelial cell collectives through coordinated movements plays a crucial role in various physiological and pathological processes and is increasingly understood at the level of large confluent monolayers. However, numerous processes rely on the migration of small groups of polarized epithelial clusters in complex environments, and their responses to external geometries remain poorly understood. To address this, we cultivated primary epithelial keratocyte tissues on adhesive microstripes, creating autonomous epithelial clusters with well-defined geometries. We showed that their migration efficiency is strongly influenced by the contact geometry, and the orientation of cell-cell contacts with respect to the direction of migration. To elucidate the underlying mechanisms, we systematically explored possible cell-cell interactions using a minimal active matter model. Our investigations revealed that a combination of velocity and polarity alignment with contact regulation of locomotion captures the experimental data, which we then validated via force and intracellular stress measurements. Furthermore, we predict that this combination of rules enables efficient navigation in complex geometries, which we confirm experimentally. Altogether, our findings provide a conceptual framework for extracting interaction rules governing the behavior of active systems interacting with physical boundaries, as well as designing principles for collective navigation in complex microenvironments.