Giant fluctuations and structural effects in a flocking epithelium

TY - JOUR

T1 - Giant fluctuations and structural effects in a flocking epithelium

AU - Giavazzi, Fabio

AU - Malinverno, Chiara

AU - Corallino, Salvatore

AU - Ginelli, Francesco

AU - Scita, Giorgio

AU - Cerbino, Roberto

N1 - We thank S Henkes for useful discussions. FGia and RC acknowledge funding from the Italian Ministry of University and Scientific Research (MIUR) under the program Futuro in Ricerca—Project ANISOFT (RBFR125H0M) and from Regione Lombardia and CARIPLO foundation under the joint action Avviso congiunto per l'incremento dell'attrattivitá del sistema ricerca lombardo e della competitivitá dei ricercatori candidati su strumenti ERC—Project 2016-0998. CM, SC and GS acknowledge funding from Associazione Italiana per la Ricerca sul Cancro (AIRC 10168 and 18621), MIUR, the Italian Ministry of Health, Ricerca Finalizzata (RF0235844), Worldwide Cancer Research (AICR-14-0335), and the European Research Council (Advanced-ERC-268836). CM was also supported by Fondazione Umberto Veronesi and SC by an AIRC fellowship. FGin acknowledges support from the Marie Curie Career Integration Grant (CIG) PCIG13-GA-2013-618399, and wish to thank the University of Milan and LibrOsteria for their hospitality while this work was underway.

PY - 2017/8/30

Y1 - 2017/8/30

N2 - 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.

AB - 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.

KW - active matter

KW - jamming transition

KW - collective cell migration

KW - non-equilibrium fluctuations

U2 - 10.1088/1361-6463/aa7f8e

DO - 10.1088/1361-6463/aa7f8e

M3 - Article

VL - 50

SP - 1

EP - 11

JO - Journal of Physics D: Applied Physics

JF - Journal of Physics D: Applied Physics

SN - 0022-3727

M1 - 384003

ER -