title: Is the mechanical activity of epithelial cells controlled by deformations or forces?
abstract: The traction forces developed by cells depend strongly on the substrate rigidity. In this letter, we characterize quantitatively this effect on MDCK epithelial cells by using a microfabricated force sensor consisting in a high-density array of soft pillars whose stiffness can be tailored by changing their height and radius to obtain a rigidity range from 2 nN/microm up to 130 nN/microm. We find that the forces exerted by the cells are proportional to the spring constant of the pillars meaning that, on average, the cells deform the pillars by the same amount whatever their rigidity. The relevant parameter may thus be a deformation rather than a force. These dynamic observations are correlated with the reinforcement of focal adhesions that increases with the substrate rigidity.
authors.affiliation: Matière et Systèmes Complexes, CNRS UMR 7057/Université Paris 7, Tour 33-34, 2 place Jussieu 75005 Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Saez
authors.forename: Axel
authors.initials: A
authors.lastname: Buguin
authors.forename: Pascal
authors.initials: P
authors.lastname: Silberzan
authors.forename: Benoît
authors.initials: B
authors.lastname: Ladoux
mesh_terms: D000818:Animals; D002460:Cell Line; D003198:Computer Simulation; D004285:Dogs; D004548:Elasticity; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology*; D007668:Kidney / Q000166:cytology / Q000502:physiology*; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D008954:Models, Biological; D010812:Physical Stimulation / Q000379:methods*; D013314:Stress, Mechanical