Abstract 17200: Altered Nuclear and Cytoskeletal Mechanics and Defective Cell Adhesion in Cardiac Myocytes Carrying the Cardiomyopathy LMNA D192G Mutation
Introduction: Previous investigations suggested that lamin A/C gene (LMNA) mutations, which cause a variety of human diseases including muscular dystrophies and dilated cardiomyopathy, alter the nuclear mechanical properties.
Hypothesis: We hypothesized that not only the nucleus, but also the whole-cell biomechanical behavior may be altered in cardiomyocytes with the dilated cardiomyopathy LMNA D192G mutation.
Methods: We combined atomic force microscopy (AFM), molecular and cellular biology methodologies to study the biomechanics of the nucleus and whole-cell. Neonatal rat ventricular myocytes (NRVMs) were infected with adenoviral vectors containing either wild type or LMNA D192G. LMNA protein expression was confirmed up to day 6. Nuclear and whole-cell biomechanics were investigated in LMNA D192G, wild type and control NRVMs, .
Results: Live-cell AFM force-deformation curves from days 1 through 6 showed that LMNA D192G nuclei displayed higher stiffness and fragility compared to controls with a peak at 72h (P<0.05), with 3 time increase in nuclear Young modulus. Furthermore, mutant NRVMs showed a severe reduction in the adhesion area between AFM probe and cell membrane compared to control and wild type. Finally, D192G NRVMs displayed increased viscoelasticity behavior measured as force decays with time during cell deformation (relaxation force test) compared to wild type and control NRVMs, suggesting loss of cytoskeleton elasticity. The altered biomechanical behavior of LMNA D192G NRVMs was rescued by wild-type LMNA (P<0.05).
Conclusions: Our study suggests that the cardiomyopathy LMNA D192G mutation has a profound effect on the whole-cell biomechanics in cardiomyocytes, extending beyond the increased nuclear stiffness and fragility, and involving cytoskeletal structural modifications and reduced cell membrane adhesion, changes that can be rescued by wild-type LMNA.
Author Disclosures: O. Sbaizero: None. T. Lanzicher: None. V. Martinelli: None. C. Long: None. D. Slavov: None. G. Del Favero: None. M. Taylor: None. L. Mestroni: None.
This research has received full or partial funding support from the American Heart Association.
- © 2014 by American Heart Association, Inc.