Name: biophysical assays to probe the mechanical properties of the interphase cell nucleus: substrate strain application and microneedle manipulation
Uploaded: 2011-09-14T12:00:00
Description: Watch this Scientific Journal Video about Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation at JoVE.com

This work was supported by the National Institutes of Health (R01 HL082792 and R01 NS059348) and the Brigham and Women's Hospital Cardiovascular Leadership Group Award.

1. Substrate strain application
The measurement of normalized nuclear strain includes the preparation of strain dishes with transparent, elastic silicone membranes as cell culture surface, plating cells onto the dishes, and acquiring images of the cells before, during and after (uniaxial or biaxial) strain application.
Preparation of silicone membrane dishes and adherence of cells 
<ol>
	<li>Each strain dish consists of a custom-made bottomless plastic dish with a di...

<ol>
	<li>Friedl, P., Wolf, K., Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nuclear+mechanics+during+cell+migration.">Nuclear mechanics during cell migration.</a> Curr Opin Cell Biol. 23, 55-64 (2011).</li><li>Mejat, A., Misteli, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LINC+complexes+in+health+and+disease.">LINC complexes in health and disease.</a> Nucleus. 1, 40-52 (2010).</li><li>Worman, H. J., Fong, L. G., Muchir, A., Young, S. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laminopathies+and+the+long+strange+trip+from+basic+cell+biology+to+therapy.">Laminopathies and the long strange trip from basic cell biology to therapy.</a> J Clin Invest. 119, 1825-1836 (2009).</li><li>Caille, N., Tardy, Y., Meister, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+strain+field+in+endothelial+cells+subjected+to+uniaxial+deformation+of+their+substrate.">Assessment of strain field in endothelial cells subjected to uniaxial deformation of their substrate.</a> Ann Biomed Eng. 26, 409-416 (1998).</li><li>Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lamins+A+and+C+but+not+lamin+B1+regulate+nuclear+mechanics.">Lamins A and C but not lamin B1 regulate nuclear mechanics.</a> J Biol Chem. 281, 25768-25780 (2006).</li><li>Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Abnormal+nuclear+shape+and+impaired+mechanotransduction+in+emerin-deficient+cells.">Abnormal nuclear shape and impaired mechanotransduction in emerin-deficient cells.</a> J Cell Biol. 170, 781-791 (2005).</li><li>Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lamin+A/C+deficiency+causes+defective+nuclear+mechanics+and+mechanotransduction.">Lamin A/C deficiency causes defective nuclear mechanics and mechanotransduction.</a> J Clin Invest. 113, 370-378 (2004).</li><li>Verstraeten, V. L., Ji, J. Y., Cummings, K. S., Lee, R. T., Lammerding, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+mechanosensitivity+and+nuclear+stiffness+in+Hutchinson-Gilford+progeria+cells:+effects+of+farnesyltransferase+inhibitors.">Increased mechanosensitivity and nuclear stiffness in Hutchinson-Gilford progeria cells: effects of farnesyltransferase inhibitors.</a> Aging Cell. 7, 383-393 (2008).</li><li>Brooks, S. V., Zerba, E., Faulkner, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Injury+to+muscle+fibres+after+single+stretches+of+passive+and+maximally+stimulated+muscles+in+mice.">Injury to muscle fibres after single stretches of passive and maximally stimulated muscles in mice.</a> J Physiol. 488, 459-469 (1995).</li><li>Maniotis, A. J., Chen, C. S., Ingber, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Demonstration+of+mechanical+connections+between+integrins,+cytoskeletal+filaments,+and+nucleoplasm+that+stabilize+nuclear+structure.">Demonstration of mechanical connections between integrins, cytoskeletal filaments, and nucleoplasm that stabilize nuclear structure.</a> Proc Natl Acad Sci. 94, 849-854 (1997).</li></ol>

Substrate strain assay
Strain application has been successfully used by us and other groups to study induced nuclear deformations in cells subjected to mechanical stress and to investigate the contribution of specific nuclear envelope proteins to nuclear stiffness.4-8 The advantage of this technique is that it probes mechanical properties of living nuclei in their normal cellular and cytoskeletal environment and that the substrate strain application resembles physiological load applica...

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent</td>
			<td>Company</td>
			<td>Catalogue number</td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>Millipore</td>
			<td>FC010</td>
		</tr>
		<tr>
			<td>MitoTracker Red FM and Green FM</td>
			<td>Invitrogen</td>
			<td>M22425 and M-7514</td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Invitrogen</td>
			<td>H3570</td>
		</tr>
		<tr>
			<td>Hank's Buffered Salt Saline</td>
			<td>Invitrogen</td>
			<td>14185</td>
		</tr>
		<tr>
			<td>Phenol free, DMEM</td>
			<td>Invitrogen</td>
			<td>21063</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Aleken Biologicals</td>
			<td>FBSS500</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Sigma</td>
			<td>P0781-100ML</td>
		</tr>
		<tr>
			<td>Borosilicate Glass with filament </td>
			<td>Sutter Instrument</td>
			<td>BF100-78-10</td>
		</tr>
		<tr>
			<td>Gloss/Gloss non-reinforced silicone sheeting, 0.005"</td>
			<td>Specialty Manufacturing Inc.</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Dulbecco's Phosphate Buffered Saline</td>
			<td>Invitrogen</td>
			<td>14200</td>
		</tr>
		<tr>
			<td>35 mm glass bottom culture dishes (FluoroDish)</td>
			<td>World Precision Instruments, INC</td>
			<td>FD35-100</td>
		</tr>
		<tr>
			<td>Braycote 804 Vacuum Grease</td>
			<td>Spi supplies</td>
			<td>05133A-AB</td>
		</tr>
	</tbody>
</table>

biophysical assays to probe the mechanical properties of the interphase cell nucleus: substrate strain application and microneedle manipulation

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.

Watch this Scientific Journal Video about Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation at JoVE.com

Biophysical Assays to Probe the Mechanical Properties of the Interphase Cell Nucleus: Substrate Strain Application and Microneedle Manipulation

We present two independent, microscope-based tools to measure the induced nuclear and cytoskeletal deformations in single, living adherent cells in response to global or localized strain application. These techniques are used to determine nuclear stiffness (i.e., deformability) and to probe intracellular force transmission between the nucleus and the cytoskeleton.

In most eukaryotic cells, the nucleus is the largest organelle and is typically 2 to 10 times stiffer than the surrounding cytoskeleton; consequently, the ...

Research

JoVE Journal

Biology

Mechanical Stimulation of Stem Cells Using Cyclic Uniaxial Strain

The role of mechanical forces in the development and maintenance of biological tissues is well documented, including several mechanically regulated ...

Purification of the M. magneticum Strain AMB-1 Magnetosome Associated Protein MamA&Delta;41

Magnetotactic bacteria comprise a diverse group of aquatic microorganisms that are able to orientate themselves along geomagnetic fields. This behavior is ...

Photobleaching Assays (FRAP &amp; FLIP) to Measure Chromatin Protein Dynamics in Living Embryonic Stem Cells

Photobleaching Assays FRAP & FLIP to Measure Chromatin Protein Dynamics in Living Embryonic Stem Cells

Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Loss In Photobleaching (FLIP) enable the study of protein dynamics in living cells with ...

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

Pharmacological and Functional Genetic Assays to Manipulate Regeneration of the Planarian Dugesia japonica

Free-living planarian flatworms have a long history of experimental usage owing to their remarkable regenerative abilities1. Small fragments excised from ...

Selective Capture of 5-hydroxymethylcytosine from Genomic DNA

5-methylcytosine (5-mC) constitutes ~2-8% of the total cytosines in human genomic DNA and impacts a broad range of biological functions, including gene ...

Super-resolution Imaging of the Bacterial Division Machinery

Bacterial cell division requires the coordinated  assembly of more than ten essential proteins at midcell1,2. Central  to this process is the formation of ...

Application of an In vitro DNA Protection Assay to Visualize Stress Mediation Properties of the Dps Protein

Application of an In vitro DNA Protection Assay to Visualize Stress Mediation Properties of the Dps Protein

Oxidative stress is an unavoidable byproduct of  aerobic life.  Molecular oxygen is  essential for terrestrial metabolism, but it also takes part in many ...

The Cell-based L-Glutathione Protection Assays to Study Endocytosis and Recycling of Plasma Membrane Proteins

Membrane trafficking involves transport of proteins from the plasma membrane to the cell interior (i.e. endocytosis) followed by trafficking to lysosomes ...

Probe-based Real-time PCR Approaches for Quantitative Measurement of microRNAs

Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that ...

Sequential Application of Glass Coverslips to Assess the Compressive Stiffness of the Mouse Lens: Strain and Morphometric Analyses

The eye lens is a transparent organ that refracts and focuses light to form a clear image on the retina. In humans, ciliary muscles contract to deform the ...