Collective cell chirality

Individual and collective cell polarity has fascinated mathematical modelers for a long time. Recently, a more subtle type of symmetry breaking started to attract attention of experimentalists and theorists alike - emergence of chirality in single cells and in cell groups. I will describe a joint project with Bershadsky/Tee lab to understand collective cell chirality on adhesive islands. From the initial microscopy data, two potential models emerged: in one, cells elongate and slowly rotate, and neighboring cells align with each other. When the collective rotation is stopped by the island boundaries, chirality emerges. In an alternative model, cells become chiral due to stress fibers turns inside the cells on the boundary, and then the polarity pattern propagates inward into the cellular groups. We used agent-based modeling to simulate these two hypotheses. The models make many predictions, and I will show how we discriminated between the models by comparing the data to these predictions.