Биофизические Анализы для исследования механических свойств клеточного ядра Interphase: Субстрат приложений Процедить и микроиглы Манипуляция
Summary
Приведем два независимых, микроскоп-инструменты для измерения индуцированных ядерных и цитоскелета деформации в отдельных живых прилипшие клетки в ответ на глобальные и локализованной деформации приложения. Эти методы используются для определения ядерных жесткости (то есть, деформируемость) и зонд внутриклеточной передачи силы между ядром и цитоскелета.
Abstract
In most eukaryotic cells, the nucleus is the largest organelle and is typically 2 to 10 times stiffer than the surrounding cytoskeleton; consequently, the physical properties of the nucleus contribute significantly to the overall biomechanical behavior of cells under physiological and pathological conditions. For example, in migrating neutrophils and invading cancer cells, nuclear stiffness can pose a major obstacle during extravasation or passage through narrow spaces within tissues.1 On the other hand, the nucleus of cells in mechanically active tissue such as muscle requires sufficient structural support to withstand repetitive mechanical stress. Importantly, the nucleus is tightly integrated into the cellular architecture; it is physically connected to the surrounding cytoskeleton, which is a critical requirement for the intracellular movement and positioning of the nucleus, for example, in polarized cells, synaptic nuclei at neuromuscular junctions, or in migrating cells.2 Not surprisingly, mutations in nuclear envelope proteins such as lamins and nesprins, which play a critical role in determining nuclear stiffness and nucleo-cytoskeletal coupling, have been shown recently to result in a number of human diseases, including Emery-Dreifuss muscular dystrophy, limb-girdle muscular dystrophy, and dilated cardiomyopathy.3 To investigate the biophysical function of diverse nuclear envelope proteins and the effect of specific mutations, we have developed experimental methods to study the physical properties of the nucleus in single, living cells subjected to global or localized mechanical perturbation. Measuring induced nuclear deformations in response to precisely applied substrate strain application yields important information on the deformability of the nucleus and allows quantitative comparison between different mutations or cell lines deficient for specific nuclear envelope proteins. Localized cytoskeletal strain application with a microneedle is used to complement this assay and can yield additional information on intracellular force transmission between the nucleus and the cytoskeleton. Studying nuclear mechanics in intact living cells preserves the normal intracellular architecture and avoids potential artifacts that can arise when working with isolated nuclei. Furthermore, substrate strain application presents a good model for the physiological stress experienced by cells in muscle or other tissues (e.g., vascular smooth muscle cells exposed to vessel strain). Lastly, while these tools have been developed primarily to study nuclear mechanics, they can also be applied to investigate the function of cytoskeletal proteins and mechanotransduction signaling.
Protocol
Discussion
Анализ основания напряжение
Штамм заявка была успешно использована нами и другими группами для изучения индуцированных ядерных деформаций в клетках подвергаются механическим нагрузкам и исследовать вклад белков ядерного конверт ядерной жесткости. 4-8 преимущест?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Работа выполнена при поддержке Национального института здоровья (R01 и R01 HL082792 NS059348) и Бригам и женской больницы сердечно-сосудистой премии группы лидерства.
Materials
| Name of Reagent | Company | Catalogue number |
| Fibronectin | Millipore | FC010 |
| MitoTracker Red FM and Green FM | Invitrogen | M22425 and M-7514 |
| Hoechst 33342 | Invitrogen | H3570 |
| Hank’s Buffered Salt Saline | Invitrogen | 14185 |
| Phenol free, DMEM | Invitrogen | 21063 |
| Fetal bovine serum | Aleken Biologicals | FBSS500 |
| Penicillin/Streptomycin | Sigma | P0781-100ML |
| Borosilicate Glass with filament | Sutter Instrument | BF100-78-10 |
| Gloss/Gloss non-reinforced silicone sheeting, 0.005″ | Specialty Manufacturing Inc. | |
| Dulbecco’s Phosphate Buffered Saline | Invitrogen | 14200 |
| 35 mm glass bottom culture dishes (FluoroDish) | World Precision Instruments, INC | FD35-100 |
| Braycote 804 Vacuum Grease | Spi supplies | 05133A-AB |
References
- Friedl, P., Wolf, K., Lammerding, J. Nuclear mechanics during cell migration. Curr Opin Cell Biol. 23, 55-64 (2011).
- Mejat, A., Misteli, T. LINC complexes in health and disease. Nucleus. 1, 40-52 (2010).
- Worman, H. J., Fong, L. G., Muchir, A., Young, S. G. Laminopathies and the long strange trip from basic cell biology to therapy. J Clin Invest. 119, 1825-1836 (2009).
- Caille, N., Tardy, Y., Meister, J. J. Assessment of strain field in endothelial cells subjected to uniaxial deformation of their substrate. Ann Biomed Eng. 26, 409-416 (1998).
- Lammerding, J. Lamins A and C but not lamin B1 regulate nuclear mechanics. J Biol Chem. 281, 25768-25780 (2006).
- Lammerding, J. Abnormal nuclear shape and impaired mechanotransduction in emerin-deficient cells. J Cell Biol. 170, 781-791 (2005).
- Lammerding, J. Lamin A/C deficiency causes defective nuclear mechanics and mechanotransduction. J Clin Invest. 113, 370-378 (2004).
- Verstraeten, V. L., Ji, J. Y., Cummings, K. S., Lee, R. T., Lammerding, J. Increased mechanosensitivity and nuclear stiffness in Hutchinson-Gilford progeria cells: effects of farnesyltransferase inhibitors. Aging Cell. 7, 383-393 (2008).
- Brooks, S. V., Zerba, E., Faulkner, J. A. Injury to muscle fibres after single stretches of passive and maximally stimulated muscles in mice. J Physiol. 488, 459-469 (1995).
- Maniotis, A. J., Chen, C. S., Ingber, D. E. Demonstration of mechanical connections between integrins, cytoskeletal filaments, and nucleoplasm that stabilize nuclear structure. Proc Natl Acad Sci. 94, 849-854 (1997).
