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Measuring nucleus mechanics within a living multicellular organism: Physical decoupling and attenuated recovery rate are physiological protective mechanisms of the cell nucleus under high mechanical load.
- Source :
-
Molecular biology of the cell [Mol Biol Cell] 2020 Aug 01; Vol. 31 (17), pp. 1943-1950. Date of Electronic Publication: 2020 Jun 17. - Publication Year :
- 2020
-
Abstract
- Nuclei within cells are constantly subjected to compressive, tensile, and shear forces, which regulate nucleoskeletal and cytoskeletal remodeling, activate signaling pathways, and direct cell-fate decisions. Multiple rheological methods have been adapted for characterizing the response to applied forces of isolated nuclei and nuclei within intact cells. However, in vitro measurements fail to capture the viscoelastic modulation of nuclear stress-strain relationships by the physiological tethering to the surrounding cytoskeleton, extracellular matrix and cells, and tissue-level architectures. Using an equiaxial stretching apparatus, we applied a step stress and measured nucleus deformation dynamics within living Caenorhabditis elegans nematodes. Nuclei deformed nonmonotonically under constant load. Nonmonotonic deformation was conserved across tissues and robust to nucleoskeletal and cytoskeletal perturbations, but it required intact linker of nucleoskeleton and cytoskeleton complex attachments. The transition from creep to strain recovery fits a tensile-compressive linear viscoelastic model that is indicative of nucleoskeletal-cytoskeletal decoupling under high load. Ce-lamin ( lmn-1 ) knockdown softened the nucleus, whereas nematode aging stiffened the nucleus and decreased deformation recovery rate. Recovery lasted minutes rather than seconds due to physiological damping of the released mechanical energy, thus protecting nuclear integrity and preventing chromatin damage.
- Subjects :
- Animals
Biomechanical Phenomena
Caenorhabditis elegans
Chromatin metabolism
Cytoskeleton metabolism
Extracellular Matrix metabolism
Microtubules metabolism
Models, Biological
Nuclear Envelope metabolism
Nuclear Matrix metabolism
Stress, Mechanical
Cell Nucleus metabolism
Molecular Imaging methods
Rheology methods
Subjects
Details
- Language :
- English
- ISSN :
- 1939-4586
- Volume :
- 31
- Issue :
- 17
- Database :
- MEDLINE
- Journal :
- Molecular biology of the cell
- Publication Type :
- Academic Journal
- Accession number :
- 32583745
- Full Text :
- https://doi.org/10.1091/mbc.E20-01-0085