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Ge Y, Lin YH, Lautscham LA, Goldmann WH, Fabry B, Naumann CA. N-cadherin-functionalized polymer-tethered multi-bilayer: a cell surface-mimicking substrate to probe cellular mechanosensitivity. Soft Matter 2016; 12:8274-8284. [PMID: 27731476 DOI: 10.1039/c6sm01673a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Fate and function of anchorage-dependent cells depend on a variety of environmental cues, including those of mechanical nature. Previous progress in the understanding of cellular mechanosensitivity has been closely linked to the availability of artificial cell substrates of adjustable viscoelasticity, allowing for a direct correlation between substrate stiffness and cell response. Exemplary, polymeric gel substrates with polymer-conjugated cell-substrate linkers provided valuable insight into the role of mechanical signals during cell migration in an extracellular matrix environment. In contrast, less is known about the role of external mechanical signals across cell-cell interfaces, in part, due to the limitations of traditional polymeric substrates to mimic the remarkable dynamics of cell-cell linkages. To overcome this shortcoming, we introduce a cell surface-mimicking cell substrate of adjustable stiffness, which is comprised of a polymer-tethered lipid multi-bilayer stack with N-cadherin linkers. Unlike traditional polymeric cell substrates with polymer-conjugated linkers, this novel artificial cell substrate is able to replicate the dynamic assembly/disassembly of cadherin linkers into linker clusters and the long-range movements of cadherin-based cell-substrate linkages observed at cell-cell interfaces. Moreover, substrate stiffness can be changed by adjusting the number of bilayers in the multi-bilayer stack, thus enabling the analysis of cellular mechanosensitivity in the presence of artificial cell-cell linkages. The presented biomembrane-mimicking cell substrate provides a valuable tool to explore the functional role of mechanical cues from neighboring cells.
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Affiliation(s)
- Y Ge
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
| | - Y H Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
| | - L A Lautscham
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - W H Goldmann
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - B Fabry
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen, 91052, Germany
| | - C A Naumann
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis, 46202 USA.
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Lautscham LA, Kämmerer C, Lange JR, Kolb T, Mark C, Schilling A, Strissel PL, Strick R, Gluth C, Rowat AC, Metzner C, Fabry B. Migration in Confined 3D Environments Is Determined by a Combination of Adhesiveness, Nuclear Volume, Contractility, and Cell Stiffness. Biophys J 2016; 109:900-13. [PMID: 26331248 DOI: 10.1016/j.bpj.2015.07.025] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 07/17/2015] [Accepted: 07/20/2015] [Indexed: 01/13/2023] Open
Abstract
In cancer metastasis and other physiological processes, cells migrate through the three-dimensional (3D) extracellular matrix of connective tissue and must overcome the steric hindrance posed by pores that are smaller than the cells. It is currently assumed that low cell stiffness promotes cell migration through confined spaces, but other factors such as adhesion and traction forces may be equally important. To study 3D migration under confinement in a stiff (1.77 MPa) environment, we use soft lithography to fabricate polydimethylsiloxane (PDMS) devices consisting of linear channel segments with 20 μm length, 3.7 μm height, and a decreasing width from 11.2 to 1.7 μm. To study 3D migration in a soft (550 Pa) environment, we use self-assembled collagen networks with an average pore size of 3 μm. We then measure the ability of four different cancer cell lines to migrate through these 3D matrices, and correlate the results with cell physical properties including contractility, adhesiveness, cell stiffness, and nuclear volume. Furthermore, we alter cell adhesion by coating the channel walls with different amounts of adhesion proteins, and we increase cell stiffness by overexpression of the nuclear envelope protein lamin A. Although all cell lines are able to migrate through the smallest 1.7 μm channels, we find significant differences in the migration velocity. Cell migration is impeded in cell lines with larger nuclei, lower adhesiveness, and to a lesser degree also in cells with lower contractility and higher stiffness. Our data show that the ability to overcome the steric hindrance of the matrix cannot be attributed to a single cell property but instead arises from a combination of adhesiveness, nuclear volume, contractility, and cell stiffness.
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Affiliation(s)
- Lena A Lautscham
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany.
| | - Christoph Kämmerer
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Janina R Lange
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Thorsten Kolb
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Christoph Mark
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Achim Schilling
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Pamela L Strissel
- Laboratory for Molecular Medicine, Department of Gynecology and Obstetrics, University-Clinic Erlangen, Erlangen, Germany
| | - Reiner Strick
- Laboratory for Molecular Medicine, Department of Gynecology and Obstetrics, University-Clinic Erlangen, Erlangen, Germany
| | - Caroline Gluth
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Amy C Rowat
- Department of Integrative Biology and Physiology, UCLA, Los Angeles, California
| | - Claus Metzner
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Ben Fabry
- Biophysics Group, Department of Physics, University of Erlangen-Nuremberg, Erlangen, Germany
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Lange JR, Steinwachs J, Kolb T, Lautscham LA, Harder I, Whyte G, Fabry B. Microconstriction arrays for high-throughput quantitative measurements of cell mechanical properties. Biophys J 2016; 109:26-34. [PMID: 26153699 DOI: 10.1016/j.bpj.2015.05.029] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 12/15/2022] Open
Abstract
We describe a method for quantifying the mechanical properties of cells in suspension with a microfluidic device consisting of a parallel array of micron-sized constrictions. Using a high-speed charge-coupled device camera, we measure the flow speed, cell deformation, and entry time into the constrictions of several hundred cells per minute during their passage through the device. From the flow speed and the occupation state of the microconstriction array with cells, the driving pressure across each constriction is continuously computed. Cell entry times into microconstrictions decrease with increased driving pressure and decreased cell size according to a power law. From this power-law relationship, the cell elasticity and fluidity can be estimated. When cells are treated with drugs that depolymerize or stabilize the cytoskeleton or the nucleus, elasticity and fluidity data from all treatments collapse onto a master curve. Power-law rheology and collapse onto a master curve are predicted by the theory of soft glassy materials and have been previously shown to describe the mechanical behavior of cells adhering to a substrate. Our finding that this theory also applies to cells in suspension provides the foundation for a quantitative high-throughput measurement of cell mechanical properties with microfluidic devices.
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Affiliation(s)
- Janina R Lange
- Biophysics Group, Department of Physics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Julian Steinwachs
- Biophysics Group, Department of Physics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Thorsten Kolb
- Biophysics Group, Department of Physics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany; Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
| | - Lena A Lautscham
- Biophysics Group, Department of Physics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Irina Harder
- Max Planck Institute for the Science of Light, Erlangen, Germany
| | - Graeme Whyte
- Institute of Biological Chemistry, Biophysics and Bioengineering, Department of Physics, Heriot-Watt University, Edinburgh, UK
| | - Ben Fabry
- Biophysics Group, Department of Physics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany.
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Schürmann S, Wagner S, Herlitze S, Fischer C, Gumbrecht S, Wirth-Hücking A, Prölß G, Lautscham LA, Fabry B, Goldmann WH, Nikolova-Krstevski V, Martinac B, Friedrich O. The IsoStretcher: An isotropic cell stretch device to study mechanical biosensor pathways in living cells. Biosens Bioelectron 2016; 81:363-372. [PMID: 26991603 DOI: 10.1016/j.bios.2016.03.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 12/31/2022]
Abstract
Mechanosensation in many organs (e.g. lungs, heart, gut) is mediated by biosensors (like mechanosensitive ion channels), which convert mechanical stimuli into electrical and/or biochemical signals. To study those pathways, technical devices are needed that apply strain profiles to cells, and ideally allow simultaneous live-cell microscopy analysis. Strain profiles in organs can be complex and multiaxial, e.g. in hollow organs. Most devices in mechanobiology apply longitudinal uniaxial stretch to adhered cells using elastomeric membranes to study mechanical biosensors. Recent approaches in biomedical engineering have employed intelligent systems to apply biaxial or multiaxial stretch to cells. Here, we present an isotropic cell stretch system (IsoStretcher) that overcomes some previous limitations. Our system uses a rotational swivel mechanism that translates into a radial displacement of hooks attached to small circular silicone membranes. Isotropicity and focus stability are demonstrated with fluorescent beads, and transmission efficiency of elastomer membrane stretch to cellular area change in HeLa/HEK cells. Applying our system to lamin-A overexpressing fibrosarcoma cells, we found a markedly reduced stretch of cell area, indicative of a stiffer cytoskeleton. We also investigated stretch-activated Ca(2+) entry into atrial HL-1 myocytes. 10% isotropic stretch induced robust oscillating increases in intracellular Fluo-4 Ca(2+) fluorescence. Store-operated Ca(2+) entry was not detected in these cells. The Isostretcher provides a useful versatile tool for mechanobiology.
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Affiliation(s)
- S Schürmann
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany
| | - S Wagner
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany; Department of Physics, Biophysics Group, FAU, Henkestr. 91, 91052 Erlangen, Germany
| | - S Herlitze
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany
| | - C Fischer
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany
| | - S Gumbrecht
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany
| | - A Wirth-Hücking
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany
| | - G Prölß
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany
| | - L A Lautscham
- Department of Physics, Biophysics Group, FAU, Henkestr. 91, 91052 Erlangen, Germany
| | - B Fabry
- Department of Physics, Biophysics Group, FAU, Henkestr. 91, 91052 Erlangen, Germany
| | - W H Goldmann
- Department of Physics, Biophysics Group, FAU, Henkestr. 91, 91052 Erlangen, Germany
| | - V Nikolova-Krstevski
- Molecular Cardiology Division, Victor Chang Cardiac Research Institute, 405 Liverpool St, Darlinghurst, NSW 2010 Sydney, Australia
| | - B Martinac
- Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst NSW 2010, Australia; St Vincent's Clinical School, University of New South Wales, Darlinghurst NSW 2010, Australia
| | - O Friedrich
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Paul-Gordan-Str.3, 91052 Erlangen, Germany.
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Auernheimer V, Lautscham LA, Leidenberger M, Friedrich O, Kappes B, Fabry B, Goldmann WH. Vinculin phosphorylation at residues Y100 and Y1065 is required for cellular force transmission. J Cell Sci 2015; 128:3435-43. [PMID: 26240176 DOI: 10.1242/jcs.172031] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 07/27/2015] [Indexed: 01/13/2023] Open
Abstract
The focal adhesion protein vinculin connects the actin cytoskeleton, through talin and integrins, with the extracellular matrix. Vinculin consists of a globular head and tail domain, which undergo conformational changes from a closed auto-inhibited conformation in the cytoplasm to an open conformation in focal adhesions. Src-mediated phosphorylation has been suggested to regulate this conformational switch. To explore the role of phosphorylation in vinculin activation, we used knock-out mouse embryonic fibroblasts re-expressing different vinculin mutants in traction microscopy, magnetic tweezer microrheology, FRAP and actin-binding assays. Compared to cells expressing wild-type or constitutively active vinculin, we found reduced tractions, cytoskeletal stiffness, adhesion strength, and increased vinculin dynamics in cells expressing constitutively inactive vinculin or vinculin where Src-mediated phosphorylation was blocked by replacing tyrosine at position 100 and/or 1065 with a non-phosphorylatable phenylalanine residue. Replacing tyrosine residues with phospho-mimicking glutamic acid residues restored cellular tractions, stiffness and adhesion strength, as well as vinculin dynamics, and facilitated vinculin-actin binding. These data demonstrate that Src-mediated phosphorylation is necessary for vinculin activation, and that phosphorylation controls cytoskeletal mechanics by regulating force transmission between the actin cytoskeleton and focal adhesion proteins.
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Affiliation(s)
- Vera Auernheimer
- Department of Physics, Biophysics Group, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Lena A Lautscham
- Department of Physics, Biophysics Group, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Maria Leidenberger
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Barbara Kappes
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Ben Fabry
- Department of Physics, Biophysics Group, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Wolfgang H Goldmann
- Department of Physics, Biophysics Group, University of Erlangen-Nuremberg, 91052 Erlangen, Germany
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Lautscham LA, Lin CY, Auernheimer V, Naumann CA, Goldmann WH, Fabry B. Biomembrane-mimicking lipid bilayer system as a mechanically tunable cell substrate. Biomaterials 2014; 35:3198-207. [PMID: 24439398 PMCID: PMC4026006 DOI: 10.1016/j.biomaterials.2013.12.091] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 12/22/2013] [Indexed: 11/26/2022]
Abstract
Cell behavior such as cell adhesion, spreading, and contraction critically depends on the elastic properties of the extracellular matrix. It is not known, however, how cells respond to viscoelastic or plastic material properties that more closely resemble the mechanical environment cells encounter in the body. In this report, we employ viscoelastic and plastic biomembrane-mimicking cell substrates. The compliance of the substrates can be tuned by increasing the number of polymer-tethered bilayers. This leaves the density and conformation of adhesive ligands on the top bilayer unaltered. We then observe the response of fibroblasts to these property changes. For comparison, we also study the cells on soft polyacrylamide and hard glass surfaces. Cell morphology, motility, cell stiffness, contractile forces and adhesive contact size all decrease on more compliant matrices but are less sensitive to changes in matrix dissipative properties. These data suggest that cells are able to feel and respond predominantly to the effective matrix compliance, which arises as a combination of substrate and adhesive ligand mechanical properties.
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Affiliation(s)
- Lena A Lautscham
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany.
| | - Corey Y Lin
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis 46202, USA
| | - Vera Auernheimer
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany
| | - Christoph A Naumann
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University, Indianapolis 46202, USA
| | - Wolfgang H Goldmann
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany
| | - Ben Fabry
- Department of Biophysics, University of Erlangen-Nuremberg, Erlangen 91052, Germany
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Lautscham LA, Yu-Hung Lin C, Auernheimer V, Minner D, Goldmann WH, Naumann CA, Fabry B. Mechanosensing of Cells in Laminin-Fuctionalized Biomembrane-Mimicking Substrates. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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