Coherent Motion of Monolayer Sheets under Active and Passive Confinement: From Build-up to Consequence

Abstract

Coherent angular motion of cell collectives plays a vital role in many physiological processes including tissue morphogenesis and glandular formation. Various studies have established the inevitable role of confinement in setting up rotational mode of migration of cells. In the present study, we examine the implications of various confining conditions on built up of coherent motion of cells. As any perturbation of coherent rotation leads to the interruption of the related activities, we also investigate the effects of different perturbations on coherently rotating cells. A self propelled particle based model is used, wherein each cell is assumed as motile particle and interacts with neighboring cells via harmonic forces. Using this model, we show that cells, when confined in circular geometry, exhibit coherent motion with cell density, cell-cell adhesion stiffness and size of the tissue dictating the pattern of the motion. Further we also show that even motile cells confined inside a passive tissue of non-motile cells are capable of exhibiting coherent rotation. In this case, depending upon the properties of external tissue cells, motile cells exhibit different migratory patterns, which suggest that it is not necessary to have a geometric confinement for built up of coherence. In the later part of the study, where the effect of various perturbations are examined, we show that synchronous division of cells can change the direction of coherent rotation of cells. Finally when the confinement is removed, cells are shown to migrate in different pattern depending up on the stiffness of cell- cell connection which determine the cohesivity of the system. Together, these results show how various parameters can regulate the onset and the presence of different modes of coherent motion of tissues.