Viscoelastic Cell Mechanics and actin remodelling are dependent on the rate of applied pressure
Viscoelastic Cell Mechanics and actin remodelling are dependent on the rate of applied pressure
Background: living cells are subjected to external and internal mechanical stresses. The effects of these stresses on the deformation and subsequent biological response of the cells remains unclear. This study tested the hypothesis that the rate at which pressure (or stress) is applied influence the viscoelastic properties of the cell associated with differences in the dynamics of the actin cytoskeleton.
Principal finding: micropipette aspiration was used to determine the instantaneous and equilibrium moduli and the viscosity of isolated chondrocytes based on the standard linear solid (SLS) model and a variation of this incorporating Boltzmann superposition. Cells were visualised for 180 seconds following aspiration to 7 cmH2O at 0.35, 0.70 and 5.48 cmH2O/sec. Cell recovery was then examined for a further 180 seconds once the pressure had been removed. Reducing the rate of application of pressure reduced the levels of cell deformation and recovery associated with a significant increase in modulus and viscosity. Using GFP transfection and confocal microscopy, we show that chondrocyte deformation involves distortion, disassembly and subsequent reassembly of the cortical actin cytoskeleton. At faster pressure rates, cell deformation produced an increase in cell volume associated with membrane bleb formation. GFP-actin transfection inhibited the pressure rate dependent variation in cell mechanics indicating that this behaviour is regulated by GFP-sensitive actin dynamics.
Conclusion: we suggest that slower rates of aspiration pressure enable greater levels of cortical actin distortion. This is partially inhibited by GFP or faster aspiration rates leading to membrane bleb formation and an increase in cell volume. Thus the rate of application of pressure regulates the viscoelastic mechanical properties of living cells through pressure rate sensitive differences in actin dynamics. Therefore cells appear softer when aspirated at a faster rate in contrast to what is expected of a normal viscoelastic material
e43938
Pravincumar, Priyanka
c30c7191-4a55-4d6d-b8ae-f424eab8ba07
Bader, Dan L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Knight, Martin M.
03701351-a8b9-4b66-8237-fca60c6b5412
2012
Pravincumar, Priyanka
c30c7191-4a55-4d6d-b8ae-f424eab8ba07
Bader, Dan L.
9884d4f6-2607-4d48-bf0c-62bdcc0d1dbf
Knight, Martin M.
03701351-a8b9-4b66-8237-fca60c6b5412
Pravincumar, Priyanka, Bader, Dan L. and Knight, Martin M.
(2012)
Viscoelastic Cell Mechanics and actin remodelling are dependent on the rate of applied pressure.
PLoS ONE, 7 (9), .
(doi:10.1371/journal.pone.0043938).
(PMID:22984454)
Abstract
Background: living cells are subjected to external and internal mechanical stresses. The effects of these stresses on the deformation and subsequent biological response of the cells remains unclear. This study tested the hypothesis that the rate at which pressure (or stress) is applied influence the viscoelastic properties of the cell associated with differences in the dynamics of the actin cytoskeleton.
Principal finding: micropipette aspiration was used to determine the instantaneous and equilibrium moduli and the viscosity of isolated chondrocytes based on the standard linear solid (SLS) model and a variation of this incorporating Boltzmann superposition. Cells were visualised for 180 seconds following aspiration to 7 cmH2O at 0.35, 0.70 and 5.48 cmH2O/sec. Cell recovery was then examined for a further 180 seconds once the pressure had been removed. Reducing the rate of application of pressure reduced the levels of cell deformation and recovery associated with a significant increase in modulus and viscosity. Using GFP transfection and confocal microscopy, we show that chondrocyte deformation involves distortion, disassembly and subsequent reassembly of the cortical actin cytoskeleton. At faster pressure rates, cell deformation produced an increase in cell volume associated with membrane bleb formation. GFP-actin transfection inhibited the pressure rate dependent variation in cell mechanics indicating that this behaviour is regulated by GFP-sensitive actin dynamics.
Conclusion: we suggest that slower rates of aspiration pressure enable greater levels of cortical actin distortion. This is partially inhibited by GFP or faster aspiration rates leading to membrane bleb formation and an increase in cell volume. Thus the rate of application of pressure regulates the viscoelastic mechanical properties of living cells through pressure rate sensitive differences in actin dynamics. Therefore cells appear softer when aspirated at a faster rate in contrast to what is expected of a normal viscoelastic material
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Published date: 2012
Organisations:
Faculty of Health Sciences
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Local EPrints ID: 347079
URI: http://eprints.soton.ac.uk/id/eprint/347079
ISSN: 1932-6203
PURE UUID: 962165a2-138d-453a-91f1-d455a0d636e2
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Date deposited: 17 Jan 2013 11:55
Last modified: 14 Mar 2024 12:45
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Author:
Priyanka Pravincumar
Author:
Martin M. Knight
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