Nuclear Lamin Protein C Is Linked to Lineage-Specific, Whole-Cell Mechanical Properties
Lamin proteins confer nuclear integrity and relay external mechanical cues that drive changes in gene expression. However, the influence these lamins have on whole-cell mechanical properties is unknown. We hypothesized that protein expression of lamins A, B1, and C would depend on the integrity of the actin cytoskeleton and correlate with cellular elasticity and viscoelasticity.
To test these hypotheses, we examined the protein expression of lamins A, B1, and C across five different cell lines with varied mechanical properties. Additionally, we treated representative “soft/stiff” cell types with cytochalasin D and LMNA siRNA to determine the effect of a more compliant whole-cell phenotype on lamin A, B1 and C protein expression.
A positive, linear correlation existed between lamin C protein expression and average cell moduli/apparent viscosity. Though moderate correlations existed between lamin A/B1 protein expression and whole-cell mechanical properties, they were statistically insignificant. Inhibition of actin polymerization, via cytochalasin D treatment, resulted in reduced cell elasticity, viscoelasticity, and lamin A and C protein expression in “stiff” MG-63 cells. In “soft” HEK-293T cells, this treatment reduced cell elasticity and viscoelasticity but did not affect lamin B1 or C protein expression. Additionally, LMNA siRNA treatment of MG-63 cells decreased whole-cell elasticity and viscoelasticity.
These findings suggest that lamin C protein expression is strongly associated with whole-cell mechanical properties and could potentially serve as a biomarker for mechanophenotype.
KeywordsMechanophenotype Elasticity Viscoelasticity Atomic force microscopy Cytoskeleton Mechanical biomarkers
We would like to thank Dr. Jeffrey Morgan for his gift of NHF cells. We would also like to acknowledge the Brown Genomics Core Facility and Dr. Christoph Schorl for assistance with fluorescence-based western blot detection. This work by supported by NIH Grants R01 AR063642 and P20 GM104937 (EMD) and R25 GM083270 (RDGC) and NSF CAREER Award CBET 1253189 (EMD).
This work by supported by NIH Grants R01 AR063642 and P20 GM104937 (EMD) and R25 GM083270 (RDGC) and NSF CAREER Award CBET 1253189 (EMD).
Conflict of interest
Authors RDGC, JSS, VCF, and EMD have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
R.D.G.C. and E.M.D. designed all experiments. R.D.G.C. conducted all AFM experiments. R.D.G.C. and V.C.F. conducted all western blot experiments. J.S.S. conduced all qPCR experiments. R.D.G.C. and E.M.D. analyzed the data and wrote the manuscript.
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