Format

Send to

Choose Destination
Biophys J. 2018 Jun 5;114(11):2743-2755. doi: 10.1016/j.bpj.2018.03.037.

Collective Cell Behavior in Mechanosensing of Substrate Thickness.

Author information

1
Centre for Human Development, Stem Cells and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, United Kingdom.
2
Centre for Human Development, Stem Cells and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, United Kingdom; Mechanical Engineering, University of Southampton, Southampton, United Kingdom.
3
Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, Iowa.
4
Biomedical Imaging Unit, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.
5
Institute of Lightweight Design and Structural Biomechanics, Technische Universität Wien, Vienna, Austria.
6
Mechanical Engineering, University of Southampton, Southampton, United Kingdom; Department of Mechanical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium.
7
Centre for Craniofacial and Regenerative Biology, King's College London, London, United Kingdom.
8
Mechanical Engineering, University of Southampton, Southampton, United Kingdom.
9
Centre for Human Development, Stem Cells and Regeneration, Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, United Kingdom; Mechanical Engineering, University of Southampton, Southampton, United Kingdom. Electronic address: n.d.evans@soton.ac.uk.

Abstract

Extracellular matrix stiffness has a profound effect on the behavior of many cell types. Adherent cells apply contractile forces to the material on which they adhere and sense the resistance of the material to deformation-its stiffness. This is dependent on both the elastic modulus and the thickness of the material, with the corollary that single cells are able to sense underlying stiff materials through soft hydrogel materials at low (<10 μm) thicknesses. Here, we hypothesized that cohesive colonies of cells exert more force and create more hydrogel deformation than single cells, therefore enabling them to mechanosense more deeply into underlying materials than single cells. To test this, we modulated the thickness of soft (1 kPa) elastic extracellular-matrix-functionalized polyacrylamide hydrogels adhered to glass substrates and allowed colonies of MG63 cells to form on their surfaces. Cell morphology and deformations of fluorescent fiducial-marker-labeled hydrogels were quantified by time-lapse fluorescence microscopy imaging. Single-cell spreading increased with respect to decreasing hydrogel thickness, with data fitting to an exponential model with half-maximal response at a thickness of 3.2 μm. By quantifying cell area within colonies of defined area, we similarly found that colony-cell spreading increased with decreasing hydrogel thickness but with a greater half-maximal response at 54 μm. Depth-sensing was dependent on Rho-associated protein kinase-mediated cellular contractility. Surface hydrogel deformations were significantly greater on thick hydrogels compared to thin hydrogels. In addition, deformations extended greater distances from the periphery of colonies on thick hydrogels compared to thin hydrogels. Our data suggest that by acting collectively, cells mechanosense rigid materials beneath elastic hydrogels at greater depths than individual cells. This raises the possibility that the collective action of cells in colonies or sheets may allow cells to sense structures of differing material properties at comparatively large distances.

PMID:
29874622
PMCID:
PMC6027966
DOI:
10.1016/j.bpj.2018.03.037
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center