Giant fluctuations and structural effects in a flocking epithelium

Abstract

Epithelial cells cultured in a monolayer are very motile in isolation but reach a near-jammed state when mitotic division increases their number above a critical threshold. We have recently shown that a monolayer can be reawakened by over-expression of a single protein, RAB5A, a master regulator of endocytosis. This reawakening of motility was explained in term of a flocking transition that promotes the emergence of a large-scale collective migratory pattern. Here we focus on the impact of this reawakening on the structural properties of the monolayer. We find that the unjammed monolayer is characterised by a fluidisation at the single cell level and by enhanced non-equilibrium large-scale number fluctuations at a larger length scale. Also with the help of numerical simulations, we trace back the origin of these fluctuations to the self-propelled active nature of the constituents and to the existence of a local alignment mechanism, leading to the spontaneous breaking of the orientational symmetry.

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Cited by in corpus (15)

• Active glasses
• Learning hydrodynamic equations for active matter from particle simulations and experiments
• Geometric frustration and solid-solid transitions in model 2D tissue
• Quantitative Assessment of the Toner and Tu Theory of Polar Flocks
• Self-Aligning Polar Active Matter
• Hydrodynamic Theory of Flocking in the Presence of Quenched Disorder
• Tracking collective cell motion by topological data analysis
• Designing, Synthesizing and Modeling Active Fluids
• Multiple dynamic regimes in a coarsening foam
• Clustering and anisotropic correlated percolation in polar flocks
• Minimum scaling model and exact exponents for the Nambu-Goldstone modes in the Vicsek Model
• Thermodynamic constraints and exact scaling exponents of flocking matter
• Polarization and dynamic phases of aligning active matter in periodic obstacle arrays
• Giant density fluctuations in locally hyperuniform states
• Phases and homogeneous ordered states in alignment-based self-propelled particle models