Mechano-chemical feedback under confinement drives single-cell rotation

The emergence of a preferred sense of rotation, or chirality, is common in systems with many interacting active constituents. A biologically relevant example is the formation of rotating multicellular structures during morphogenesis. An important question in such systems, where individual agents are out of equilibrium, is whether chiral symmetry breaking can occur at the constituent level. Here, we address this issue through a cellular phase field model that accounts for cell deformation, confinement by the extracellular matrix, and cell polarization governed by stochastic excitable dynamics. Numerical simulations of the model demonstrate not only that rotational motion of a single cell is possible, but also how it can be maintained over many rotations despite internal noise. We show that confinement weakening increases the persistence of the rotational motion, which is closely related to the creation of larger protrusions. We characterize this persistence by coarse-graining the numerical data into a semi- Markovian renewal process. Finally, we reveal how changes in cell shape modulate local excitable polarization dynamics through a mechanical feedback, enhancing rotational persistence.