101
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Schwarz US. To buckle or not to buckle. NATURE MATERIALS 2020; 19:8-9. [PMID: 31853032 DOI: 10.1038/s41563-019-0543-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
- Ulrich S Schwarz
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany.
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102
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Callens SJP, Uyttendaele RJC, Fratila-Apachitei LE, Zadpoor AA. Substrate curvature as a cue to guide spatiotemporal cell and tissue organization. Biomaterials 2019; 232:119739. [PMID: 31911284 DOI: 10.1016/j.biomaterials.2019.119739] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/23/2019] [Accepted: 12/25/2019] [Indexed: 12/11/2022]
Abstract
Recent evidence clearly shows that cells respond to various physical cues in their environments, guiding many cellular processes and tissue morphogenesis, pathology, and repair. One aspect that is gaining significant traction is the role of local geometry as an extracellular cue. Elucidating how geometry affects cell and tissue behavior is, indeed, crucial to design artificial scaffolds and understand tissue growth and remodeling. Perhaps the most fundamental descriptor of local geometry is surface curvature, and a growing body of evidence confirms that surface curvature affects the spatiotemporal organization of cells and tissues. While well-defined in differential geometry, curvature remains somewhat ambiguously treated in biological studies. Here, we provide a more formal curvature framework, based on the notions of mean and Gaussian curvature, and summarize the available evidence on curvature guidance at the cell and tissue levels. We discuss the involved mechanisms, highlighting the interplay between tensile forces and substrate curvature that forms the foundation of curvature guidance. Moreover, we show that relatively simple computational models, based on some application of curvature flow, are able to capture experimental tissue growth remarkably well. Since curvature guidance principles could be leveraged for tissue regeneration, the implications for geometrical scaffold design are also discussed. Finally, perspectives on future research opportunities are provided.
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Affiliation(s)
- Sebastien J P Callens
- Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft, 2628CD, the Netherlands.
| | - Rafael J C Uyttendaele
- Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft, 2628CD, the Netherlands
| | - Lidy E Fratila-Apachitei
- Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft, 2628CD, the Netherlands
| | - Amir A Zadpoor
- Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft, 2628CD, the Netherlands
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103
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Kaurin D, Arroyo M. Surface Tension Controls the Hydraulic Fracture of Adhesive Interfaces Bridged by Molecular Bonds. PHYSICAL REVIEW LETTERS 2019; 123:228102. [PMID: 31868410 DOI: 10.1103/physrevlett.123.228102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Biological function requires cell-cell adhesions to tune their cohesiveness; for instance, during the opening of new fluid-filled cavities under hydraulic pressure. To understand the physical mechanisms supporting this adaptability, we develop a stochastic model for the hydraulic fracture of adhesive interfaces bridged by molecular bonds. We find that surface tension strongly enhances the stability of these interfaces by controlling flaw sensitivity, lifetime, and optimal architecture in terms of bond clustering. We also show that bond mobility embrittles adhesions and changes the mechanism of decohesion. Our study provides a mechanistic background to understand the biological regulation of cell-cell cohesion and fracture.
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Affiliation(s)
- Dimitri Kaurin
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
| | - Marino Arroyo
- Universitat Politècnica de Catalunya-BarcelonaTech, 08034 Barcelona, Spain
- Institute for Bioengineering of Catalonia, The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain
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104
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Monemian Esfahani A, Rosenbohm J, Reddy K, Jin X, Bouzid T, Riehl B, Kim E, Lim JY, Yang R. Tissue Regeneration from Mechanical Stretching of Cell-Cell Adhesion. Tissue Eng Part C Methods 2019; 25:631-640. [PMID: 31407627 PMCID: PMC6859692 DOI: 10.1089/ten.tec.2019.0098] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/05/2019] [Indexed: 01/09/2023] Open
Abstract
Cell-cell adhesion complexes are macromolecular adhesive organelles that integrate cells into tissues. This mechanochemical coupling in cell-cell adhesion is required for a large number of cell behaviors, and perturbations of the cell-cell adhesion structure or related mechanotransduction pathways can lead to critical pathological conditions such as skin and heart diseases, arthritis, and cancer. Mechanical stretching has been a widely used method to stimulate the mechanotransduction process originating from the cell-cell adhesion and cell-extracellular matrix (ECM) complexes. These studies aimed to reveal the biophysical processes governing cell proliferation, wound healing, gene expression regulation, and cell differentiation in various tissues, including cardiac, muscle, vascular, and bone. This review explores techniques in mechanical stretching in two-dimensional settings with different stretching regimens on different cell types. The mechanotransduction responses from these different cell types will be discussed with an emphasis on their biophysical transformations during mechanical stretching and the cross talk between the cell-cell and cell-ECM adhesion complexes. Therapeutic aspects of mechanical stretching are reviewed considering these cellular responses after the application of mechanical forces, with a focus on wound healing and tissue regeneration. Impact Statement Mechanical stretching has been proposed as a therapeutic option for tissue regeneration and wound healing. It has been accepted that mechanotransduction processes elicited by mechanical stretching govern cellular response and behavior, and these studies have predominantly focused on the cell-extracellular matrix (ECM) sites. This review serves the mechanobiology community by shifting the focus of mechanical stretching effects from cell-ECM adhesions to the less examined cell-cell adhesions, which we believe play an equally important role in orchestrating the response pathways.
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Affiliation(s)
- Amir Monemian Esfahani
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Jordan Rosenbohm
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Keerthana Reddy
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Xiaowei Jin
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Tasneem Bouzid
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Brandon Riehl
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Eunju Kim
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Jung Yul Lim
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
- Mary and Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, Nebraska
| | - Ruiguo Yang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
- Mary and Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, Nebraska
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, Nebraska
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105
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Abstract
Cell-cell junctions are specializations of the plasma membrane responsible for physically integrating cells into tissues. We are now beginning to appreciate the diverse impacts that mechanical forces exert upon the integrity and function of these junctions. Currently, this is best understood for cadherin-based adherens junctions in epithelia and endothelia, where cell-cell adhesion couples the contractile cytoskeletons of cells together to generate tissue-scale tension. Junctional tension participates in morphogenesis and tissue homeostasis. Changes in tension can also be detected by mechanotransduction pathways that allow cells to communicate with each other. In this review, we discuss progress in characterising the forces present at junctions in physiological conditions; the cellular mechanisms that generate intrinsic tension and detect changes in tension; and, finally, we consider how tissue integrity is maintained in the face of junctional stresses.
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106
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Mongera A, Michaut A, Guillot C, Xiong F, Pourquié O. Mechanics of Anteroposterior Axis Formation in Vertebrates. Annu Rev Cell Dev Biol 2019; 35:259-283. [PMID: 31412208 PMCID: PMC7394480 DOI: 10.1146/annurev-cellbio-100818-125436] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The vertebrate anteroposterior axis forms through elongation of multiple tissues during embryogenesis. This process is based on tissue-autonomous mechanisms of force generation and intertissue mechanical coupling whose failure leads to severe developmental anomalies such as body truncation and spina bifida. Similar to other morphogenetic modules, anteroposterior body extension requires both the rearrangement of existing materials-such as cells and extracellular matrix-and the local addition of new materials, i.e., anisotropic growth, through cell proliferation, cell growth, and matrix deposition. Numerous signaling pathways coordinate body axis formation via regulation of cell behavior during tissue rearrangements and/or volumetric growth. From a physical perspective, morphogenesis depends on both cell-generated forces and tissue material properties. As the spatiotemporal variation of these mechanical parameters has recently been explored in the context of vertebrate body elongation, the study of this process is likely to shed light on the cross talk between signaling and mechanics during morphogenesis.
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Affiliation(s)
- Alessandro Mongera
- Department of Genetics, Harvard Medical School, and Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA;
| | - Arthur Michaut
- Department of Genetics, Harvard Medical School, and Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA;
| | - Charlène Guillot
- Department of Genetics, Harvard Medical School, and Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA;
| | - Fengzhu Xiong
- Department of Genetics, Harvard Medical School, and Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA;
| | - Olivier Pourquié
- Department of Genetics, Harvard Medical School, and Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA;
- Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts 02138, USA
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107
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Aufderhorst-Roberts A, Koenderink GH. Stiffening and inelastic fluidization in vimentin intermediate filament networks. SOFT MATTER 2019; 15:7127-7136. [PMID: 31334536 DOI: 10.1039/c9sm00590k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Intermediate filaments are cytoskeletal proteins that are key regulators of cell mechanics, a role which is intrinsically tied to their hierarchical structure and their unique ability to accommodate large axial strains. However, how the single-filament response to applied strains translates to networks remains unclear, particularly with regards to the crosslinking role played by the filaments' disordered "tail" domains. Here we test the role of these noncovalent crosslinks in the nonlinear rheology of reconstituted networks of the intermediate filament protein vimentin, probing their stress- and rate-dependent mechanics. Similarly to previous studies we observe elastic stress-stiffening but unlike previous work we identify a characteristic yield stress σ*, above which the networks exhibit rate-dependent softening of the network, referred to as inelastic fluidization. By investigating networks formed from tail-truncated vimentin, in which noncovalent crosslinking is suppressed, and glutaraldehyde-treated vimentin, in which crosslinking is made permanent, we show that rate-dependent inelastic fluidization is a direct consequence of vimentin's transient crosslinking. Surprisingly, although the tail-tail crosslinks are individually weak, the effective timescale for stress relaxation of the network exceeds 1000 s at σ*. Vimentin networks can therefore maintain their integrity over a large range of strains (up to ∼1000%) and loading rates (10-3 to 10-1 s-1). Our results provide insight into how the hierarchical structure of vimentin networks contributes to the cell's ability to be deformable yet strong.
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108
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Barriga EH, Mayor R. Adjustable viscoelasticity allows for efficient collective cell migration. Semin Cell Dev Biol 2019; 93:55-68. [PMID: 29859995 PMCID: PMC6854469 DOI: 10.1016/j.semcdb.2018.05.027] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 12/22/2022]
Abstract
Cell migration is essential for a wide range of biological processes such as embryo morphogenesis, wound healing, regeneration, and also in pathological conditions, such as cancer. In such contexts, cells are required to migrate as individual entities or as highly coordinated collectives, both of which requiring cells to respond to molecular and mechanical cues from their environment. However, whilst the function of chemical cues in cell migration is comparatively well understood, the role of tissue mechanics on cell migration is just starting to be studied. Recent studies suggest that the dynamic tuning of the viscoelasticity within a migratory cluster of cells, and the adequate elastic properties of its surrounding tissues, are essential to allow efficient collective cell migration in vivo. In this review we focus on the role of viscoelasticity in the control of collective cell migration in various cellular systems, mentioning briefly some aspects of single cell migration. We aim to provide details on how viscoelasticity of collectively migrating groups of cells and their surroundings is adjusted to ensure correct morphogenesis, wound healing, and metastasis. Finally, we attempt to show that environmental viscoelasticity triggers molecular changes within migrating clusters and that these new molecular setups modify clusters' viscoelasticity, ultimately allowing them to migrate across the challenging geometries of their microenvironment.
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Affiliation(s)
- Elias H Barriga
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK
| | - Roberto Mayor
- Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK.
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109
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Khalilgharibi N, Fouchard J, Asadipour N, Barrientos R, Duda M, Bonfanti A, Yonis A, Harris A, Mosaffa P, Fujita Y, Kabla A, Mao Y, Baum B, Muñoz JJ, Miodownik M, Charras G. Stress relaxation in epithelial monolayers is controlled by the actomyosin cortex. NATURE PHYSICS 2019; 15:839-847. [PMID: 33569083 PMCID: PMC7116713 DOI: 10.1038/s41567-019-0516-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 04/01/2019] [Indexed: 05/19/2023]
Abstract
Epithelial monolayers are one-cell thick tissue sheets that line most of the body surfaces, separating internal and external environments. As part of their function, they must withstand extrinsic mechanical stresses applied at high strain rates. However, little is known about how monolayers respond to mechanical deformations. Here, by subjecting suspended epithelial monolayers to stretch, we find that they dissipate stresses on a minute timescale and that relaxation can be described by a power law with an exponential cut-off at timescales larger than ~10 s. This process involves an increase in monolayer length, pointing to active remodelling of cellular biopolymers at the molecular scale during relaxation. Strikingly, monolayers consisting of tens of thousands of cells relax stress with similar dynamics to single rounded cells and both respond similarly to perturbations of the actomyosin cytoskeleton. By contrast, cell-cell junctional complexes and intermediate filaments do not relax tissue stress, but form stable connections between cells, allowing monolayers to behave rheologically as single cells. Taken together our data show that actomyosin dynamics governs the rheological properties of epithelial monolayers, dissipating applied stresses, and enabling changes in monolayer length.
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Affiliation(s)
- Nargess Khalilgharibi
- London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK
- Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, Gower Street, London WC1E 6BT, UK
| | - Jonathan Fouchard
- London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK
| | - Nina Asadipour
- Laboratori de Càlcul Numèric (LaCàN), Dept. Mathematics, Esc. d'Enginyeria Barcelona Est (EEBE), Universitat Politècnica de Catalunya - Barcelona Tech (UPC), 08036, Barcelona, Spain
| | - Ricardo Barrientos
- Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, Gower Street, London WC1E 6BT, UK
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Maria Duda
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | | | - Amina Yonis
- London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK
- Department of Cell and Developmental Biology, University College London, UK
| | - Andrew Harris
- London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK
- Department of Physics, University College London, London WC1E 6BT, UK
- Engineering Doctorate Program, Department of Chemistry, University College London, London WC1H 0AJ, UK
- Department of Bioengineering and Biophysics Program, University of California, Berkeley, 648 Stanley Hall MC 1762, Berkeley, CA 94720, USA
| | - Payman Mosaffa
- Laboratori de Càlcul Numèric (LaCàN), Dept. Mathematics, Esc. d'Enginyeria Barcelona Est (EEBE), Universitat Politècnica de Catalunya - Barcelona Tech (UPC), 08036, Barcelona, Spain
| | | | - Alexandre Kabla
- Department of Mechanical Engineering, Cambridge University, UK
| | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
- Institute for the Physics of Living Systems, University College London, UK
| | - José J Muñoz
- Laboratori de Càlcul Numèric (LaCàN), Dept. Mathematics, Esc. d'Enginyeria Barcelona Est (EEBE), Universitat Politècnica de Catalunya - Barcelona Tech (UPC), 08036, Barcelona, Spain
- Barcelona Graduate School of Mathematics (BGSMath), Spain
| | - Mark Miodownik
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK
- Department of Cell and Developmental Biology, University College London, UK
- Institute for the Physics of Living Systems, University College London, UK
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110
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Montanino A, Deryckere A, Famaey N, Seuntjens E, Kleiven S. Mechanical characterization of squid giant axon membrane sheath and influence of the collagenous endoneurium on its properties. Sci Rep 2019; 9:8969. [PMID: 31222074 PMCID: PMC6586665 DOI: 10.1038/s41598-019-45446-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/07/2019] [Indexed: 12/15/2022] Open
Abstract
To understand traumas to the nervous system, the relation between mechanical load and functional impairment needs to be explained. Cellular-level computational models are being used to capture the mechanism behind mechanically-induced injuries and possibly predict these events. However, uncertainties in the material properties used in computational models undermine the validity of their predictions. For this reason, in this study the squid giant axon was used as a model to provide a description of the axonal mechanical behavior in a large strain and high strain rate regime [Formula: see text], which is relevant for injury investigations. More importantly, squid giant axon membrane sheaths were isolated and tested under dynamic uniaxial tension and relaxation. From the lumen outward, the membrane sheath presents: an axolemma, a layer of Schwann cells followed by the basement membrane and a prominent layer of loose connective tissue consisting of fibroblasts and collagen. Our results highlight the load-bearing role of this enwrapping structure and provide a constitutive description that could in turn be used in computational models. Furthermore, tests performed on collagen-depleted membrane sheaths reveal both the substantial contribution of the endoneurium to the total sheath's response and an interesting increase in material nonlinearity when the collagen in this connective layer is digested. All in all, our results provide useful insights for modelling the axonal mechanical response and in turn will lead to a better understanding of the relationship between mechanical insult and electrophysiological outcome.
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Affiliation(s)
- Annaclaudia Montanino
- Division of Neuronic Engineering, Royal Institute of Technology (KTH), Huddinge, Sweden.
| | - Astrid Deryckere
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Nele Famaey
- Biomechanics section, KU Leuven, Leuven, Belgium
| | - Eve Seuntjens
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Svein Kleiven
- Division of Neuronic Engineering, Royal Institute of Technology (KTH), Huddinge, Sweden
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111
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Bernardi L, Giampietro C, Marina V, Genta M, Mazza E, Ferrari A. Adaptive reorientation of endothelial collectives in response to strain. Integr Biol (Camb) 2019; 10:527-538. [PMID: 30112523 DOI: 10.1039/c8ib00092a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mature epithelial monolayers share the ability to coherently respond to external mechanical stimuli. Tissue remodeling requires cell shape changes and coordinated movements. Human endothelia provide an exquisite example of such emerging collective activities. As part of their function in maintaining body homeostasis under variable hemodynamic loadings, endothelial ensembles must dynamically adapt to wall shear stress and cyclic deformation. While the alignment of several types of cells, including fibroblasts, osteoblasts and epithelial tissues, in response to various flow conditions or wall shear stress levels has been described in detail, less is known about collective endothelial remodeling under pure wall deformation. Here, using a custom-developed bioreactor, we exposed mature human endothelia to two distinct physiological levels of cyclic loading, generating overlapping gradients of strain. Endothelial cells remodeled depending on the level of imposed strain yielding local variations of cell density. In particular, a collective cell orientation orthogonal to the main direction of strain was observed at low levels of wall deformation, while cells reoriented parallel to the main direction of strain at high levels of wall deformation. The tissue adaptation depended on the establishment of mature adherens junctions, which were reinforced by the polarized recruitment of the adaptor protein vinculin. The pivotal role of cell-to-cell junctions was confirmed by the biochemical inhibition of vascular endothelial cadherin homotypic contacts, which impaired the collective remodeling. Together, our data establish wall deformation as an independent determinant of endothelial architecture with direct implications in vascular physiopathology.
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Affiliation(s)
- Laura Bernardi
- ETH Zurich, Institute for Mechanical Systems, 8092 Zürich, Switzerland.
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112
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Hydraulic control of mammalian embryo size and cell fate. Nature 2019; 571:112-116. [PMID: 31189957 DOI: 10.1038/s41586-019-1309-x] [Citation(s) in RCA: 174] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 05/21/2019] [Indexed: 11/08/2022]
Abstract
Size control is fundamental in tissue development and homeostasis1,2. Although the role of cell proliferation in these processes has been widely studied, the mechanisms that control embryo size-and how these mechanisms affect cell fate-remain unknown. Here we use the mouse blastocyst as a model to unravel a key role of fluid-filled lumen in the control of embryo size and specification of cell fate. We find that there is a twofold increase in lumenal pressure during blastocyst development, which translates into a concomitant increase in cell cortical tension and tissue stiffness of the trophectoderm that lines the lumen. Increased cortical tension leads to vinculin mechanosensing and maturation of functional tight junctions, which establishes a positive feedback loop to accommodate lumen growth. When the cortical tension reaches a critical threshold, cell-cell adhesion cannot be sustained during mitotic entry, which leads to trophectoderm rupture and blastocyst collapse. A simple theory of hydraulically gated oscillations recapitulates the observed dynamics of size oscillations, and predicts the scaling of embryo size with tissue volume. This theory further predicts that disrupted tight junctions or increased tissue stiffness lead to a smaller embryo size, which we verified by biophysical, embryological, pharmacological and genetic perturbations. Changes in lumenal pressure and size can influence the cell division pattern of the trophectoderm, and thereby affect cell allocation and fate. Our study reveals how lumenal pressure and tissue mechanics control embryo size at the tissue scale, which is coupled to cell position and fate at the cellular scale.
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113
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Sorba F, Poulin A, Ischer R, Shea H, Martin-Olmos C. Integrated elastomer-based device for measuring the mechanics of adherent cell monolayers. LAB ON A CHIP 2019; 19:2138-2146. [PMID: 31115420 DOI: 10.1039/c9lc00075e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cells in the body collectively sustain mechanical deformations in almost all physiological functions. From the morphogenesis stage, cells' ability to sustain stress is essential for the body's well-being. Several pathologies have been associated with abnormal mechanical properties, thus suggesting the Young's modulus as a biomarker to diagnose diseases and determine their progression. Advancements in the field are quite slow because current techniques for measuring cell and tissue mechanics rely on complex and bulky measurement platforms that have low repeatability rates and limited measurement time-scales. We present the first miniaturized system that allows accurate quantification of the Young's modulus of adherent cell monolayers over a longer time (1-2 days). Our approach is based on tensile testing and optical read-out. Thanks to a thoughtful design and material choice, we are able to miniaturize tensile testing platforms into a 1 cm × 2 cm device. We provide highly repeatable Young's modulus measurements in the relevant range between 3 kPa and 300 kPa, over time and under physiological conditions, thus representing an interesting alternative to existing measurement platforms. Furthermore, the compatibility with standard biological equipment, continuous optical imaging and measurements on all types of adherent cells make this device highly versatile. Measurements on human sarcoma osteogenic (SaOS2) and Madin-Darby canine kidney cells (MDCK) are reported. The demonstrated capability to measure real-time changes in mechanical properties, such as after chemical treatment, opens the door for investigating the effects of drugs on cell mechanics.
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Affiliation(s)
- Francesca Sorba
- Swiss Center for Electronics and Microtechnology, CSEM SA, Neuchâtel, Switzerland.
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114
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Proag A, Monier B, Suzanne M. Physical and functional cell-matrix uncoupling in a developing tissue under tension. Development 2019; 146:dev.172577. [PMID: 31064785 PMCID: PMC6589077 DOI: 10.1242/dev.172577] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 04/26/2019] [Indexed: 01/02/2023]
Abstract
Tissue mechanics play a crucial role in organ development. They rely on the properties of cells and the extracellular matrix (ECM), but the relative physical contribution of cells and ECM to morphogenesis is poorly understood. Here, we have analyzed the behavior of the peripodial epithelium (PE) of the Drosophila leg disc in the light of the dynamics of its cellular and ECM components. The PE undergoes successive changes during leg development, including elongation, opening and removal to free the leg. During elongation, we found that the ECM and cell layer are progressively uncoupled. Concomitantly, the tension, mainly borne by the ECM at first, builds up in the cell monolayer. Then, each layer of the peripodial epithelium is removed by an independent mechanism: while the ECM layer withdraws following local proteolysis, cellular monolayer withdrawal is independent of ECM degradation and is driven by myosin II-dependent contraction. These results reveal a surprising physical and functional cell-matrix uncoupling in a monolayer epithelium under tension during development. This article has an associated ‘The people behind the papers’ interview. Highlighted Article: The independent behavior of extracellular matrix and cell monolayer of an epithelium under tension during Drosophila leg development highlights the interplay between tissue mechanics and cell-matrix coupling.
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Affiliation(s)
- Amsha Proag
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Bruno Monier
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
| | - Magali Suzanne
- LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse 31062, France
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115
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A Combined AFM and Lateral Stretch Device Enables Microindentation Analyses of Living Cells at High Strains. Methods Protoc 2019; 2:mps2020043. [PMID: 31164622 PMCID: PMC6632168 DOI: 10.3390/mps2020043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/13/2019] [Accepted: 05/21/2019] [Indexed: 12/22/2022] Open
Abstract
Mechanical characterization of living cells undergoing substantial external strain promises insights into material properties and functional principles of mechanically active tissues. However, due to the high strains that occur in physiological situations (up to 50%) and the complex structure of living cells, suitable experimental techniques are rare. In this study, we introduce a new system composed of an atomic force microscope (AFM), a cell stretching system based on elastomeric substrates, and light microscopy. With this system, we investigated the influence of mechanical stretch on monolayers of keratinocytes. In repeated indentations at the same location on one particular cell, we found significant stiffening at 25% and 50% strain amplitude. To study the contribution of intermediate filaments, we used a mutant keratinocyte cell line devoid of all keratins. For those cells, we found a softening in comparison to the wild type, which was even more pronounced at higher strain amplitudes.
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116
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Bashirzadeh Y, Dumbali S, Qian S, Maruthamuthu V. Mechanical response of an epithelial island subject to uniaxial stretch on a hybrid silicone substrate. Cell Mol Bioeng 2019; 12:33-40. [PMID: 31105800 DOI: 10.1007/s12195-018-00560-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Introduction The mechanical response of large multi-cellular collectives to external stretch has remained largely unexplored, despite its relevance to normal function and to external challenges faced by some tissues. Here, we introduced a simple hybrid silicone substrate to enable external stretch while providing a physiologically relevant physical micro-environment for cells. Methods We micropatterned epithelial islands on the substrate using a stencil to allow for a circular island shape without restraining island edges. We then used traction force microscopy to determine the strain energy and the inter-cellular sheet tension within the island as a function of time after stretch. Results While the strain energy stored in the substrate for unstretched cell islands stayed constant over time, a uniaxial 10% stretch resulted in an abrupt increase, followed by sustained increase in the strain energy of the islands over tens of minutes, indicating slower dynamics than for single cells reported previously. The sheet tension at the island mid-line perpendicular to the stretch direction also more than doubled compared to unstretched islands. Interestingly, the sheet tension at the island mid-line parallel to the stretch direction also reached similar levels over tens of minutes indicating the tendency of the island to homogenize its internal stress. Conclusions We found that the sheet tension within large epithelial islands depends on its direction relative to that of the stretch initially, but not at longer times. We suggest that the hybrid silicone substrate provides for an accessible substrate for studying the mechanobiology of large epithelial cell islands.
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Affiliation(s)
- Yashar Bashirzadeh
- Mechanical & Aerospace Engineering, Old Dominion University, 4635 Hampton Blvd, 238e Kaufman, Norfolk, VA 23529 USA
| | - Sandeep Dumbali
- Mechanical & Aerospace Engineering, Old Dominion University, 4635 Hampton Blvd, 238e Kaufman, Norfolk, VA 23529 USA
| | - Shizhi Qian
- Mechanical & Aerospace Engineering, Old Dominion University, 4635 Hampton Blvd, 238e Kaufman, Norfolk, VA 23529 USA
| | - Venkat Maruthamuthu
- Mechanical & Aerospace Engineering, Old Dominion University, 4635 Hampton Blvd, 238e Kaufman, Norfolk, VA 23529 USA
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117
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D'Angelo A, Dierkes K, Carolis C, Salbreux G, Solon J. In Vivo Force Application Reveals a Fast Tissue Softening and External Friction Increase during Early Embryogenesis. Curr Biol 2019; 29:1564-1571.e6. [PMID: 31031116 PMCID: PMC6509404 DOI: 10.1016/j.cub.2019.04.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 02/06/2019] [Accepted: 04/03/2019] [Indexed: 11/23/2022]
Abstract
During development, cell-generated forces induce tissue-scale deformations to shape the organism [1,2]. The pattern and extent of these deformations depend not solely on the temporal and spatial profile of the generated force fields but also on the mechanical properties of the tissues that the forces act on. It is thus conceivable that, much like the cell-generated forces, the mechanical properties of tissues are modulated during development in order to drive morphogenesis toward specific developmental endpoints. Although many approaches have recently emerged to assess effective mechanical parameters of tissues [3-8], they could not quantitatively relate spatially localized force induction to tissue-scale deformations in vivo. Here, we present a method that overcomes this limitation. Our approach is based on the application of controlled forces on a single microparticle embedded in an individual cell of an embryo. Combining measurements of bead displacement with the analysis of induced deformation fields in a continuum mechanics framework, we quantify material properties of the tissue and follow their changes over time. In particular, we uncover a rapid change in tissue response occurring during Drosophila cellularization, resulting from a softening of the blastoderm and an increase of external friction. We find that the microtubule cytoskeleton is a major contributor to epithelial mechanics at this stage. We identify developmentally controlled modulations in perivitelline spacing that can account for the changes in friction. Overall, our method allows for the measurement of key mechanical parameters governing tissue-scale deformations and flows occurring during morphogenesis.
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Affiliation(s)
- Arturo D'Angelo
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Kai Dierkes
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Carlo Carolis
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | | | - Jérôme Solon
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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118
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Serrano R, Aung A, Yeh YT, Varghese S, Lasheras JC, Del Álamo JC. Three-Dimensional Monolayer Stress Microscopy. Biophys J 2019; 117:111-128. [PMID: 31103228 DOI: 10.1016/j.bpj.2019.03.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 03/07/2019] [Accepted: 03/28/2019] [Indexed: 01/06/2023] Open
Abstract
Many biological processes involve the collective generation and transmission of mechanical stresses across cell monolayers. In these processes, the monolayer undergoes lateral deformation and bending because of the tangential and normal components of the cell-generated stresses. Monolayer stress microscopy (MSM) methods have been developed to measure the intracellular stress distribution in cell monolayers. However, current methods assume plane monolayer geometry and neglect the contribution of bending to the intracellular stresses. This work introduces a three-dimensional (3D) MSM method that calculates monolayer stress from measurements of the 3D traction stresses exerted by the cells on a flexible substrate. The calculation is carried out by imposing equilibrium of forces and moments in the monolayer, subject to external loads given by the 3D traction stresses. The equilibrium equations are solved numerically, and the algorithm is validated for synthetic loads with known analytical solutions. We present 3D-MSM measurements of monolayer stress in micropatterned islands of endothelial cells of different sizes and shapes. These data indicate that intracellular stresses caused by lateral deformation emerge collectively over long distances; they increase with the distance from the island edge until they reach a constant value that is independent of island size. On the other hand, bending-induced intracellular stresses are more concentrated spatially and remain confined to within one to two cell lengths of bending sites. The magnitude of these bending stresses is highest at the edges of the cell islands, where they can exceed the intracellular stresses caused by lateral deformations. Our data from nonpatterned monolayers suggests that biomechanical perturbations far away from monolayer edges also cause significant localized alterations in bending tension. The localized effect of bending-induced stresses may be important in processes like cellular extravasation, which are accompanied by significant normal deflections of a cell monolayer (i.e., the endothelium) and require localized changes in monolayer permeability.
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Affiliation(s)
- Ricardo Serrano
- Department of Mechanical and Aerospace Engineering, San Diego, San Diego, California.
| | - Aereas Aung
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Yi-Ting Yeh
- Department of Mechanical and Aerospace Engineering, San Diego, San Diego, California; Department of Bioengineering, San Diego, San Diego, California; Institute of Engineering in Medicine, University of California, San Diego, San Diego, California
| | - Shyni Varghese
- Department of Biomedical Engineering, Durham, North Carolina; Department of Mechanical Engineering and Material Sciences, Durham, North Carolina; Department of Orthopaedic Surgery, Duke University, Durham, North Carolina
| | - Juan C Lasheras
- Department of Mechanical and Aerospace Engineering, San Diego, San Diego, California; Department of Bioengineering, San Diego, San Diego, California; Institute of Engineering in Medicine, University of California, San Diego, San Diego, California
| | - Juan C Del Álamo
- Department of Mechanical and Aerospace Engineering, San Diego, San Diego, California.
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Fodor É, Mehandia V, Comelles J, Thiagarajan R, Gov NS, Visco P, van Wijland F, Riveline D. Spatial Fluctuations at Vertices of Epithelial Layers: Quantification of Regulation by Rho Pathway. Biophys J 2019; 114:939-946. [PMID: 29490253 DOI: 10.1016/j.bpj.2017.12.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 01/14/2023] Open
Abstract
In living matter, shape fluctuations induced by acto-myosin are usually studied in vitro via reconstituted gels, whose properties are controlled by changing the concentrations of actin, myosin, and cross-linkers. Such an approach deliberately avoids consideration of the complexity of biochemical signaling inherent to living systems. Acto-myosin activity inside living cells is mainly regulated by the Rho signaling pathway, which is composed of multiple layers of coupled activators and inhibitors. Here, we investigate how such a pathway controls the dynamics of confluent epithelial tissues by tracking the displacements of the junction points between cells. Using a phenomenological model to analyze the vertex fluctuations, we rationalize the effects of different Rho signaling targets on the emergent tissue activity by quantifying the effective diffusion coefficient, and the persistence time and length of the fluctuations. Our results reveal an unanticipated correlation between layers of activation/inhibition and spatial fluctuations within tissues. Overall, this work connects regulation via biochemical signaling with mesoscopic spatial fluctuations, with potential application to the study of structural rearrangements in epithelial tissues.
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Affiliation(s)
- Étienne Fodor
- DAMTP, Centre for Mathematical Sciences, University of Cambridge, Cambridge, United Kingdom; Laboratoire Matière et Systèmes Complexes, UMR 7057 CNRS/P7, Université Paris Diderot, Paris cedex 13, France
| | - Vishwajeet Mehandia
- Laboratory of Cell Physics, ISIS/IGBMC, Université de Strasbourg and CNRS (UMR 7006), Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS (UMR 7104), INSERM (U964), Université de Strasbourg, Illkirch, France; School of Mechanical, Materials and Energy Engineering, Indian Institute of Technology, Ropar, India
| | - Jordi Comelles
- Laboratory of Cell Physics, ISIS/IGBMC, Université de Strasbourg and CNRS (UMR 7006), Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS (UMR 7104), INSERM (U964), Université de Strasbourg, Illkirch, France
| | - Raghavan Thiagarajan
- Laboratory of Cell Physics, ISIS/IGBMC, Université de Strasbourg and CNRS (UMR 7006), Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS (UMR 7104), INSERM (U964), Université de Strasbourg, Illkirch, France
| | - Nir S Gov
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Paolo Visco
- Laboratoire Matière et Systèmes Complexes, UMR 7057 CNRS/P7, Université Paris Diderot, Paris cedex 13, France
| | - Frédéric van Wijland
- Laboratoire Matière et Systèmes Complexes, UMR 7057 CNRS/P7, Université Paris Diderot, Paris cedex 13, France
| | - Daniel Riveline
- Laboratory of Cell Physics, ISIS/IGBMC, Université de Strasbourg and CNRS (UMR 7006), Strasbourg, France; Development and Stem Cells Program, IGBMC, CNRS (UMR 7104), INSERM (U964), Université de Strasbourg, Illkirch, France.
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Duda M, Kirkland NJ, Khalilgharibi N, Tozluoglu M, Yuen AC, Carpi N, Bove A, Piel M, Charras G, Baum B, Mao Y. Polarization of Myosin II Refines Tissue Material Properties to Buffer Mechanical Stress. Dev Cell 2019; 48:245-260.e7. [PMID: 30695698 PMCID: PMC6353629 DOI: 10.1016/j.devcel.2018.12.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 11/26/2018] [Accepted: 12/21/2018] [Indexed: 11/06/2022]
Abstract
As tissues develop, they are subjected to a variety of mechanical forces. Some of these forces are instrumental in the development of tissues, while others can result in tissue damage. Despite our extensive understanding of force-guided morphogenesis, we have only a limited understanding of how tissues prevent further morphogenesis once the shape is determined after development. Here, through the development of a tissue-stretching device, we uncover a mechanosensitive pathway that regulates tissue responses to mechanical stress through the polarization of actomyosin across the tissue. We show that stretch induces the formation of linear multicellular actomyosin cables, which depend on Diaphanous for their nucleation. These stiffen the epithelium, limiting further changes in shape, and prevent fractures from propagating across the tissue. Overall, this mechanism of force-induced changes in tissue mechanical properties provides a general model of force buffering that serves to preserve the shape of tissues under conditions of mechanical stress.
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Affiliation(s)
- Maria Duda
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Natalie J Kirkland
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Nargess Khalilgharibi
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; London Centre for Nanotechnology, University College London, London WC1E 6BT, UK; Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology (CoMPLEX), University College London, London WC1E 6BT, UK
| | - Melda Tozluoglu
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Alice C Yuen
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Nicolas Carpi
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris 75005, France
| | - Anna Bove
- London Centre for Nanotechnology, University College London, London WC1E 6BT, UK; Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Matthieu Piel
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris 75005, France
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK; Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK; College of Information and Control, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China.
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121
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Banerjee S, Marchetti MC. Continuum Models of Collective Cell Migration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1146:45-66. [PMID: 31612453 DOI: 10.1007/978-3-030-17593-1_4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Collective cell migration plays a central role in tissue development, morphogenesis, wound repair and cancer progression. With the growing realization that physical forces mediate cell motility in development and physiology, a key biological question is how cells integrate molecular activities for force generation on multicellular scales. In this review we discuss recent advances in modeling collective cell migration using quantitative tools and approaches rooted in soft matter physics. We focus on theoretical models of cell aggregates as continuous active media, where the feedback between mechanical forces and regulatory biochemistry gives rise to rich collective dynamical behavior. This class of models provides a powerful predictive framework for the physiological dynamics that underlies many developmental processes, where cells need to collectively migrate like a viscous fluid to reach a target region, and then stiffen to support mechanical stresses and maintain tissue cohesion.
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123
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Williamson JJ, Salbreux G. Stability and Roughness of Interfaces in Mechanically Regulated Tissues. PHYSICAL REVIEW LETTERS 2018; 121:238102. [PMID: 30576196 PMCID: PMC6420071 DOI: 10.1103/physrevlett.121.238102] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 07/03/2018] [Indexed: 05/26/2023]
Abstract
Cell division and death can be regulated by the mechanical forces within a tissue. We study the consequences for the stability and roughness of a propagating interface by analyzing a model of mechanically regulated tissue growth in the regime of small driving forces. For an interface driven by homeostatic pressure imbalance or leader-cell motility, long and intermediate-wavelength instabilities arise, depending, respectively, on an effective viscosity of cell number change, and on substrate friction. A further mechanism depends on the strength of directed motility forces acting in the bulk. We analyze the fluctuations of a stable interface subjected to cell-level stochasticity, and find that mechanical feedback can help preserve reproducibility at the tissue scale. Our results elucidate mechanisms that could be important for orderly interface motion in developing tissues.
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Affiliation(s)
- John J Williamson
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, United Kingdom
| | - Guillaume Salbreux
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, United Kingdom
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124
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Sadeghipour E, Garcia MA, Nelson WJ, Pruitt BL. Shear-induced damped oscillations in an epithelium depend on actomyosin contraction and E-cadherin cell adhesion. eLife 2018; 7:39640. [PMID: 30427775 PMCID: PMC6235569 DOI: 10.7554/elife.39640] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/19/2018] [Indexed: 12/22/2022] Open
Abstract
Shear forces between cells occur during global changes in multicellular organization during morphogenesis and tissue growth, yet how cells sense shear forces and propagate a response across a tissue is unknown. We found that applying exogenous shear at the midline of an epithelium induced a local, short-term deformation near the shear plane, and a long-term collective oscillatory movement across the epithelium that spread from the shear-plane and gradually dampened. Inhibiting actomyosin contraction or E-cadherin trans-cell adhesion blocked oscillations, whereas stabilizing actin filaments prolonged oscillations. Combining these data with a model of epithelium mechanics supports a mechanism involving the generation of a shear-induced mechanical event at the shear plane which is then relayed across the epithelium by actomyosin contraction linked through E-cadherin. This causes an imbalance of forces in the epithelium, which is gradually dissipated through oscillatory cell movements and actin filament turnover to restore the force balance across the epithelium.
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Affiliation(s)
- Ehsan Sadeghipour
- Department of Bioengineering, Stanford University, Stanford, United States.,Department of Mechanical Engineering, Stanford University, Stanford, United States
| | - Miguel A Garcia
- Department of Biology, Stanford University, Stanford, United States
| | - William James Nelson
- Department of Biology, Stanford University, Stanford, United States.,Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States
| | - Beth L Pruitt
- Department of Bioengineering, Stanford University, Stanford, United States.,Department of Mechanical Engineering, Stanford University, Stanford, United States.,Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States.,The Stanford Cardiovascular Institute, Stanford University, Stanford, United States.,Mechanical Engineering, University of California, Santa Barbara, United States.,Biomolecular Science and Engineering, University of California, Santa Barbara, United States.,Cellular and Developmental Biology, University of California, Santa Barbara, United States
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125
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Nier V, Peyret G, d'Alessandro J, Ishihara S, Ladoux B, Marcq P. Kalman Inversion Stress Microscopy. Biophys J 2018; 115:1808-1816. [PMID: 30301513 DOI: 10.1016/j.bpj.2018.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 08/29/2018] [Accepted: 09/12/2018] [Indexed: 10/28/2022] Open
Abstract
Although mechanical cues are crucial to tissue morphogenesis and development, the tissue mechanical stress field remains poorly characterized. Given traction force time-lapse movies, as obtained by traction force microscopy of in vitro cellular sheets, we show that the tissue stress field can be estimated by Kalman filtering. After validation using numerical data, we apply Kalman inversion stress microscopy to experimental data. We combine the inferred stress field with velocity and cell-shape measurements to quantify the rheology of epithelial cell monolayers in physiological conditions, found to be close to that of an elastic and active material.
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Affiliation(s)
- Vincent Nier
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, Paris, France
| | - Grégoire Peyret
- Institut Jacques Monod, CNRS, Université Paris Diderot, Paris, France
| | | | - Shuji Ishihara
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Benoit Ladoux
- Institut Jacques Monod, CNRS, Université Paris Diderot, Paris, France; Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Philippe Marcq
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, Paris, France.
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126
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Nagre N, Cong X, Ji HL, Schreiber JM, Fu H, Pepper I, Warren S, Sill JM, Hubmayr RD, Zhao X. Inhaled TRIM72 Protein Protects Ventilation Injury to the Lung through Injury-guided Cell Repair. Am J Respir Cell Mol Biol 2018; 59:635-647. [PMID: 29958015 PMCID: PMC6236686 DOI: 10.1165/rcmb.2017-0364oc] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 06/28/2018] [Indexed: 12/27/2022] Open
Abstract
Studies showed that TRIM72 is essential for repair of alveolar cell membrane disruptions, and exogenous recombinant human TRIM72 protein (rhT72) demonstrated tissue-mending properties in animal models of tissue injury. Here we examine the mechanisms of rhT72-mediated lung cell protection in vitro and test the efficacy of inhaled rhT72 in reducing tissue pathology in a mouse model of ventilator-induced lung injury. In vitro lung cell injury was induced by glass beads and stretching. Ventilator-induced lung injury was modeled by injurious ventilation at 30 ml/kg tidal volume. Affinity-purified rhT72 or control proteins were added into culture medium or applied through nebulization. Cellular uptake and in vivo distribution of rhT72 were detected by imaging and immunostaining. Exogenous rhT72 maintains membrane integrity of alveolar epithelial cells subjected to glass bead injury in a dose-dependent manner. Inhaled rhT72 decreases the number of fatally injured alveolar cells, and ameliorates tissue-damaging indicators and cell injury markers after injurious ventilation. Using in vitro stretching assays, we reveal that rhT72 improves both cellular resilience to membrane wounding and membrane repair after injury. Image analysis detected rhT72 uptake by rat alveolar epithelial cells, which can be inhibited by a cholesterol-disrupting agent. In addition, inhaled rhT72 distributes to the distal lungs, where it colocalizes with phosphatidylserine detection on nonpermeabilized lung slices to label wounded cells. In conclusion, our study showed that inhaled rhT72 accumulates in injured lungs and protects lung tissue from ventilator injury, the mechanisms of which include improving cell resilience to membrane wounding, localizing to injured membrane, and augmenting membrane repair.
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Affiliation(s)
- Nagaraja Nagre
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
| | - Xiaofei Cong
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
| | - Hong-Long Ji
- Texas Lung Injury Institute, the University of Texas Health Science Center at Tyler, Tyler, Texas
| | - John M. Schreiber
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
| | - Hongyun Fu
- Division of Community Health and Research, Pediatrics Department and
| | - Ian Pepper
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
| | - Seth Warren
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
| | - Joshua M. Sill
- Division of Pulmonary and Critical Care, Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia; and
| | - Rolf D. Hubmayr
- Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minnesota
| | - Xiaoli Zhao
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia
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127
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Latorre E, Kale S, Casares L, Gómez-González M, Uroz M, Valon L, Nair RV, Garreta E, Montserrat N, Del Campo A, Ladoux B, Arroyo M, Trepat X. Active superelasticity in three-dimensional epithelia of controlled shape. Nature 2018; 563:203-208. [PMID: 30401836 DOI: 10.1038/s41586-018-0671-4] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 10/08/2018] [Indexed: 01/13/2023]
Abstract
Fundamental biological processes are carried out by curved epithelial sheets that enclose a pressurized lumen. How these sheets develop and withstand three-dimensional deformations has remained unclear. Here we combine measurements of epithelial tension and shape with theoretical modelling to show that epithelial sheets are active superelastic materials. We produce arrays of epithelial domes with controlled geometry. Quantification of luminal pressure and epithelial tension reveals a tensional plateau over several-fold areal strains. These extreme strains in the tissue are accommodated by highly heterogeneous strains at a cellular level, in seeming contradiction to the measured tensional uniformity. This phenomenon is reminiscent of superelasticity, a behaviour that is generally attributed to microscopic material instabilities in metal alloys. We show that in epithelial cells this instability is triggered by a stretch-induced dilution of the actin cortex, and is rescued by the intermediate filament network. Our study reveals a type of mechanical behaviour-which we term active superelasticity-that enables epithelial sheets to sustain extreme stretching under constant tension.
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Affiliation(s)
- Ernest Latorre
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain.,LaCàN, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona, Spain
| | - Sohan Kale
- LaCàN, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona, Spain
| | - Laura Casares
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain
| | - Manuel Gómez-González
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain
| | - Marina Uroz
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain
| | - Léo Valon
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain
| | - Roshna V Nair
- INM-Leibniz Institut für Neue Materialien, Saarbrücken, Germany
| | - Elena Garreta
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain
| | - Nuria Montserrat
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain.,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Barcelona, Spain
| | - Aránzazu Del Campo
- INM-Leibniz Institut für Neue Materialien, Saarbrücken, Germany.,Chemistry Department, Saarland University, Saarbrücken, Germany
| | - Benoit Ladoux
- CNRS UMR 7592, Institut Jacques Monod (IJM), Université Paris Diderot, Paris, France.,Mechanobiology Institute (MBI), National University of Singapore, Singapore, Singapore
| | - Marino Arroyo
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain. .,LaCàN, Universitat Politècnica de Catalunya-BarcelonaTech, Barcelona, Spain.
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology (BIST), Barcelona, Spain. .,Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Barcelona, Spain. .,Unitat de Biofísica i Bioenginyeria, Universitat de Barcelona, Barcelona, Spain. .,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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128
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Armon S, Bull MS, Aranda-Diaz A, Prakash M. Ultrafast epithelial contractions provide insights into contraction speed limits and tissue integrity. Proc Natl Acad Sci U S A 2018; 115:E10333-E10341. [PMID: 30309963 PMCID: PMC6217427 DOI: 10.1073/pnas.1802934115] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
By definition of multicellularity, all animals need to keep their cells attached and intact, despite internal and external forces. Cohesion between epithelial cells provides this key feature. To better understand fundamental limits of this cohesion, we study the epithelium mechanics of an ultrathin (∼25 μm) primitive marine animal Trichoplax adhaerens, composed essentially of two flat epithelial layers. With no known extracellular matrix and no nerves or muscles, T. adhaerens has been claimed to be the "simplest known living animal," yet is still capable of coordinated locomotion and behavior. Here we report the discovery of the fastest epithelial cellular contractions known in any metazoan, to be found in T. adhaerens dorsal epithelium (50% shrinkage of apical cell area within one second, at least an order of magnitude faster than other known examples). Live imaging reveals emergent contractile patterns that are mostly sporadic single-cell events, but also include propagating contraction waves across the tissue. We show that cell contraction speed can be explained by current models of nonmuscle actin-myosin bundles without load, while the tissue architecture and unique mechanical properties are softening the tissue, minimizing the load on a contracting cell. We propose a hypothesis, in which the physiological role of the contraction dynamics is to resist external stresses while avoiding tissue rupture ("active cohesion"), a concept that can be further applied to engineering of active materials.
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Affiliation(s)
- Shahaf Armon
- Department of Bioengineering, Stanford University, Stanford, CA 94305
| | | | | | - Manu Prakash
- Department of Bioengineering, Stanford University, Stanford, CA 94305;
- Chan Zuckerberg Biohub, San Francisco, CA 94158
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129
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Nestor-Bergmann A, Johns E, Woolner S, Jensen OE. Mechanical characterization of disordered and anisotropic cellular monolayers. Phys Rev E 2018; 97:052409. [PMID: 29906905 PMCID: PMC7613005 DOI: 10.1103/physreve.97.052409] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Indexed: 01/13/2023]
Abstract
We consider a cellular monolayer, described using a vertex-based model, for which cells form a spatially disordered array of convex polygons that tile the plane. Equilibrium cell configurations are assumed to minimize a global energy defined in terms of cell areas and perimeters; energy is dissipated via dynamic area and length changes, as well as cell neighbor exchanges. The model captures our observations of an epithelium from a Xenopus embryo showing that uniaxial stretching induces spatial ordering, with cells under net tension (compression) tending to align with (against) the direction of stretch, but with the stress remaining heterogeneous at the single-cell level. We use the vertex model to derive the linearized relation between tissue-level stress, strain, and strain rate about a deformed base state, which can be used to characterize the tissue’s anisotropic mechanical properties; expressions for viscoelastic tissue moduli are given as direct sums over cells. When the base state is isotropic, the model predicts that tissue properties can be tuned to a regime with high elastic shear resistance but low resistance to area changes, or vice versa.
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Affiliation(s)
- Alexander Nestor-Bergmann
- Department of Physiology, Development & Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, United Kingdom
| | - Emma Johns
- Wellcome Trust Centre for Cell-Matrix Research, School of Medical Sciences, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Sarah Woolner
- Wellcome Trust Centre for Cell-Matrix Research, School of Medical Sciences, Faculty of Biology, Medicine & Health, Manchester Academic Health Science Centre, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Oliver E Jensen
- School of Mathematics, University of Manchester, Manchester M13 9PL, United Kingdom
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130
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Yu SM, Oh JM, Lee J, Lee-Kwon W, Jung W, Amblard F, Granick S, Cho YK. Substrate curvature affects the shape, orientation, and polarization of renal epithelial cells. Acta Biomater 2018; 77:311-321. [PMID: 30006316 DOI: 10.1016/j.actbio.2018.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/25/2018] [Accepted: 07/09/2018] [Indexed: 10/28/2022]
Abstract
The unique structure of kidney tubules is representative of their specialized function. Because maintaining tubular structure and controlled diameter is critical for kidney function, it is critical to understand how topographical cues, such as curvature, might alter cell morphology and biological characteristics. Here, we examined the effect of substrate curvature on the shape and phenotype of two kinds of renal epithelial cells (MDCK and HK-2) cultured on a microchannel with a broad range of principal curvature. We found that cellular architecture on curved substrates was closely related to the cell type-specific characteristics (stiffness, cell-cell adherence) of the cells and their density, as well as the sign and degree of curvature. As the curvature increased on convex channels, HK-2 cells, having lower cell stiffness and monolayer integrity than those of MDCK cells, aligned their in-plane axis perpendicular to the channel but did not significantly change in morphology. By contrast, MDCK cells showed minimal change in both morphology and alignment. However, on concave channels, both cell types were elongated and showed longitudinal directionality, although the changes in MDCK cells were more conservative. Moreover, substrate curvature contributed to cell polarization by enhancing the expression of apical and basolateral cell markers with height increase of the cells. Our study suggests curvature to be an important guiding principle for advanced tissue model developments, and that curved and geometrically ambiguous substrates can modulate the cellular morphology and phenotype. STATEMENT OF SIGNIFICANCE In many tissues, such as renal tubules or intestinal villi, epithelial layers exist in naturally curved forms, a geometry that is not reproduced by flat cultures. Because maintaining tubular structure is critical for kidney function, it is important to understand how topographical cues, such as curvature, might alter cell morphology and biological characteristics. We found that cellular architecture on curved substrates was closely related to cell type and density, as well as the sign and degree of the curvature. Moreover, substrate curvature contributed to cell polarization by enhancing the expression of apical and basolateral cell markers with height increase. Our results suggested that substrate curvature might contribute to cellular architecture and enhance the polarization of kidney tubule cells.
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131
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Herrera-Perez RM, Kasza KE. Biophysical control of the cell rearrangements and cell shape changes that build epithelial tissues. Curr Opin Genet Dev 2018; 51:88-95. [DOI: 10.1016/j.gde.2018.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/22/2018] [Accepted: 07/16/2018] [Indexed: 11/26/2022]
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132
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Abstract
Precisely controlled cell deformations are key to cell migration, division and tissue morphogenesis, and have been implicated in cell differentiation during development, as well as cancer progression. In animal cells, shape changes are primarily driven by the cellular cortex, a thin actomyosin network that lies directly underneath the plasma membrane. Myosin-generated forces create tension in the cortical network, and gradients in tension lead to cellular deformations. Recent studies have provided important insight into the molecular control of cortical tension by progressively unveiling cortex composition and organization. In this Cell Science at a Glance article and the accompanying poster, we review our current understanding of cortex composition and architecture. We then discuss how the microscopic properties of the cortex control cortical tension. While many open questions remain, it is now clear that cortical tension can be modulated through both cortex composition and organization, providing multiple levels of regulation for this key cellular property during cell and tissue morphogenesis. Summary: A summary of the composition, architecture, mechanics and function of the cellular actin cortex, which determines the shape of animal cells, and, thus, provides the foundation for cell and tissue morphogenesis.
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Affiliation(s)
- Priyamvada Chugh
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK .,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Ewa K Paluch
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK .,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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133
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Yang Y, Levine H. Role of the supracellular actomyosin cable during epithelial wound healing. SOFT MATTER 2018; 14:4866-4873. [PMID: 29850664 DOI: 10.1039/c7sm02521a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The closure of wounds in epithelia is center to many physiological processes in both development and repair of multicellular organisms. Depending on the biochemical and mechanical environment as well as cell type, this collective cellular movement often involves coordinated cell crawling and the purse-string contraction of a supracellular actomyosin ring around the wound. However, it remains uncertain how these two mechanisms cooperatively contribute to the wound healing, and especially the role of the ring is not clear. To decipher this complex process, we develop a particle-based model that includes purse-string contraction, cell crawling and other properties incorporated with monolayers of Madin-Darby canine kidney (MDCK) cells. Our model captures the traction force patterns under several different conditions in experiments. In addition to traction force pointing away from the wound on the leading edge, we observed patterns of traction force pointing towards the wound. We show this inward pointing force pattern is induced by the purse-string contraction. Our model also explains the effects of the purse-string ring and which parameters affect the relative efficiency of these two mechanisms.
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Affiliation(s)
- Yanjun Yang
- Department of Applied Physics and Center for Theoretical Biological Physics, Rice University, Houston TX, 77251-1892, USA.
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134
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Tlili S, Gauquelin E, Li B, Cardoso O, Ladoux B, Delanoë-Ayari H, Graner F. Collective cell migration without proliferation: density determines cell velocity and wave velocity. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172421. [PMID: 29892428 PMCID: PMC5990758 DOI: 10.1098/rsos.172421] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/23/2018] [Indexed: 05/18/2023]
Abstract
Collective cell migration contributes to embryogenesis, wound healing and tumour metastasis. Cell monolayer migration experiments help in understanding what determines the movement of cells far from the leading edge. Inhibiting cell proliferation limits cell density increase and prevents jamming; we observe long-duration migration and quantify space-time characteristics of the velocity profile over large length scales and time scales. Velocity waves propagate backwards and their frequency depends only on cell density at the moving front. Both cell average velocity and wave velocity increase linearly with the cell effective radius regardless of the distance to the front. Inhibiting lamellipodia decreases cell velocity while waves either disappear or have a lower frequency. Our model combines conservation laws, monolayer mechanical properties and a phenomenological coupling between strain and polarity: advancing cells pull on their followers, which then become polarized. With reasonable values of parameters, this model agrees with several of our experimental observations. Together, our experiments and model disantangle the respective contributions of active velocity and of proliferation in monolayer migration, explain how cells maintain their polarity far from the moving front, and highlight the importance of strain-polarity coupling and density in long-range information propagation.
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Affiliation(s)
- Sham Tlili
- Laboratoire Matière et Systèmes Complexes, Université Denis Diderot - Paris 7, CNRS UMR 7057, Condorcet building, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
- Mechanobiology Institute, Department of Biological Sciences, National University of Singapore, 5A Engineering Drive, 1, 117411 Singapore
| | - Estelle Gauquelin
- Institut Jacques Monod, Université Denis Diderot - Paris 7, CNRS UMR 7592, Buffon building, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Brigitte Li
- Laboratoire Matière et Systèmes Complexes, Université Denis Diderot - Paris 7, CNRS UMR 7057, Condorcet building, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
| | - Olivier Cardoso
- Laboratoire Matière et Systèmes Complexes, Université Denis Diderot - Paris 7, CNRS UMR 7057, Condorcet building, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
| | - Benoît Ladoux
- Mechanobiology Institute, Department of Biological Sciences, National University of Singapore, 5A Engineering Drive, 1, 117411 Singapore
- Institut Jacques Monod, Université Denis Diderot - Paris 7, CNRS UMR 7592, Buffon building, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Hélène Delanoë-Ayari
- Univ. Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5306, Institut Lumière Matière, Campus LyonTech - La Doua, Kastler building, 10 rue Ada Byron, 69622 Villeurbanne Cedex, France
| | - François Graner
- Laboratoire Matière et Systèmes Complexes, Université Denis Diderot - Paris 7, CNRS UMR 7057, Condorcet building, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
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135
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Shook DR, Kasprowicz EM, Davidson LA, Keller R. Large, long range tensile forces drive convergence during Xenopus blastopore closure and body axis elongation. eLife 2018; 7:e26944. [PMID: 29533180 PMCID: PMC5896886 DOI: 10.7554/elife.26944] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 03/12/2018] [Indexed: 02/03/2023] Open
Abstract
Indirect evidence suggests that blastopore closure during gastrulation of anamniotes, including amphibians such as Xenopus laevis, depends on circumblastoporal convergence forces generated by the marginal zone (MZ), but direct evidence is lacking. We show that explanted MZs generate tensile convergence forces up to 1.5 μN during gastrulation and over 4 μN thereafter. These forces are generated by convergent thickening (CT) until the midgastrula and increasingly by convergent extension (CE) thereafter. Explants from ventralized embryos, which lack tissues expressing CE but close their blastopores, produce up to 2 μN of tensile force, showing that CT alone generates forces sufficient to close the blastopore. Uniaxial tensile stress relaxation assays show stiffening of mesodermal and ectodermal tissues around the onset of neurulation, potentially enhancing long-range transmission of convergence forces. These results illuminate the mechanobiology of early vertebrate morphogenic mechanisms, aid interpretation of phenotypes, and give insight into the evolution of blastopore closure mechanisms.
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Affiliation(s)
- David R Shook
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
| | - Eric M Kasprowicz
- Department of Internal MedicineThomas Jefferson University HospitalPhiladelphiaUnited States
| | - Lance A Davidson
- Department of Computational and Systems BiologyUniversity of PittsburghPittsburghUnited States
- Department of BioengineeringUniversity of PittsburghPittsburghUnited States
| | - Raymond Keller
- Department of BiologyUniversity of VirginiaCharlottesvilleUnited States
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136
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Mosaffa P, Rodríguez-Ferran A, Muñoz JJ. Hybrid cell-centred/vertex model for multicellular systems with equilibrium-preserving remodelling. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2928. [PMID: 28898926 DOI: 10.1002/cnm.2928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
We present a hybrid cell-centred/vertex model for mechanically simulating planar cellular monolayers undergoing cell reorganisation. Cell centres are represented by a triangular nodal network, while the cell boundaries are formed by an associated vertex network. The two networks are coupled through a kinematic constraint which we allow to relax progressively. Special attention is paid to the change of cell-cell connectivity due to cell reorganisation or remodelling events. We handle these situations by using a variable resting length and applying an Equilibrium-Preserving Mapping on the new connectivity, which computes a new set of resting lengths that preserve nodal and vertex equilibrium. We illustrate the properties of the model by simulating monolayers subjected to imposed extension and during a wound healing process. The evolution of forces and the Equilibrium-Preserving Mapping are analysed during the remodelling events. As a by-product, the proposed technique enables to recover fully vertex or fully cell-centred models in a seamless manner by modifying a numerical parameter of the model.
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Affiliation(s)
- Payman Mosaffa
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya-Barcelona Tech, Barcelona, Spain
| | - Antonio Rodríguez-Ferran
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya-Barcelona Tech, Barcelona, Spain
| | - José J Muñoz
- Laboratori de Càlcul Numèric (LaCàN), Universitat Politècnica de Catalunya-Barcelona Tech, Barcelona, Spain
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137
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Inverse tissue mechanics of cell monolayer expansion. PLoS Comput Biol 2018; 14:e1006029. [PMID: 29494578 PMCID: PMC5849322 DOI: 10.1371/journal.pcbi.1006029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/13/2018] [Accepted: 02/07/2018] [Indexed: 01/01/2023] Open
Abstract
Living tissues undergo deformation during morphogenesis. In this process, cells generate mechanical forces that drive the coordinated cell motion and shape changes. Recent advances in experimental and theoretical techniques have enabled in situ measurement of the mechanical forces, but the characterization of mechanical properties that determine how these forces quantitatively affect tissue deformation remains challenging, and this represents a major obstacle for the complete understanding of morphogenesis. Here, we proposed a non-invasive reverse-engineering approach for the estimation of the mechanical properties, by combining tissue mechanics modeling and statistical machine learning. Our strategy is to model the tissue as a continuum mechanical system and to use passive observations of spontaneous tissue deformation and force fields to statistically estimate the model parameters. This method was applied to the analysis of the collective migration of Madin-Darby canine kidney cells, and the tissue flow and force were simultaneously observed by the phase contrast imaging and traction force microscopy. We found that our monolayer elastic model, whose elastic moduli were reverse-engineered, enabled a long-term forecast of the traction force fields when given the tissue flow fields, indicating that the elasticity contributes to the evolution of the tissue stress. Furthermore, we investigated the tissues in which myosin was inhibited by blebbistatin treatment, and observed a several-fold reduction in the elastic moduli. The obtained results validate our framework, which paves the way to the estimation of mechanical properties of living tissues during morphogenesis. In order to shape the body of a multicellular organism, cells generate mechanical forces and undergo deformation. Although these forces are being increasingly determined, quantitative characterization of the relation between the deformation and forces at the tissue level remains challenging. To estimate these properties, we developed a reverse-engineering method by combining tissue mechanics modeling and statistical machine learning, and then tested this method on a common model system, the expansion of cultured cell monolayer. This statistically sound framework uses the passive observations of spontaneous deformation and force dynamics in tissues, and enables us to elucidate unperturbed mechanical processes underlying morphogenesis.
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138
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Approximate Bayesian computation reveals the importance of repeated measurements for parameterising cell-based models of growing tissues. J Theor Biol 2018; 443:66-81. [PMID: 29391171 DOI: 10.1016/j.jtbi.2018.01.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 11/22/2022]
Abstract
The growth and dynamics of epithelial tissues govern many morphogenetic processes in embryonic development. A recent quantitative transition in data acquisition, facilitated by advances in genetic and live-imaging techniques, is paving the way for new insights to these processes. Computational models can help us understand and interpret observations, and then make predictions for future experiments that can distinguish between hypothesised mechanisms. Increasingly, cell-based modelling approaches such as vertex models are being used to help understand the mechanics underlying epithelial morphogenesis. These models typically seek to reproduce qualitative phenomena, such as cell sorting or tissue buckling. However, it remains unclear to what extent quantitative data can be used to constrain these models so that they can then be used to make quantitative, experimentally testable predictions. To address this issue, we perform an in silico study to investigate whether vertex model parameters can be inferred from imaging data, and explore methods to quantify the uncertainty of such estimates. Our approach requires the use of summary statistics to estimate parameters. Here, we focus on summary statistics of cellular packing and of laser ablation experiments, as are commonly reported from imaging studies. We find that including data from repeated experiments is necessary to generate reliable parameter estimates that can facilitate quantitative model predictions.
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139
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Win Z, Buksa JM, Steucke KE, Gant Luxton GW, Barocas VH, Alford PW. Cellular Microbiaxial Stretching to Measure a Single-Cell Strain Energy Density Function. J Biomech Eng 2018; 139:2618751. [PMID: 28397957 DOI: 10.1115/1.4036440] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Indexed: 01/02/2023]
Abstract
The stress in a cell due to extracellular mechanical stimulus is determined by its mechanical properties, and the structural organization of many adherent cells suggests that their properties are anisotropic. This anisotropy may significantly influence the cells' mechanotransductive response to complex loads, and has important implications for development of accurate models of tissue biomechanics. Standard methods for measuring cellular mechanics report linear moduli that cannot capture large-deformation anisotropic properties, which in a continuum mechanics framework are best described by a strain energy density function (SED). In tissues, the SED is most robustly measured using biaxial testing. Here, we describe a cellular microbiaxial stretching (CμBS) method that modifies this tissue-scale approach to measure the anisotropic elastic behavior of individual vascular smooth muscle cells (VSMCs) with nativelike cytoarchitecture. Using CμBS, we reveal that VSMCs are highly anisotropic under large deformations. We then characterize a Holzapfel-Gasser-Ogden type SED for individual VSMCs and find that architecture-dependent properties of the cells can be robustly described using a formulation solely based on the organization of their actin cytoskeleton. These results suggest that cellular anisotropy should be considered when developing biomechanical models, and could play an important role in cellular mechano-adaptation.
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Affiliation(s)
- Zaw Win
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, 312 Church Street SE NHH 7-105, Minneapolis, MN 55455 e-mail:
| | - Justin M Buksa
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, 312 Church Street SE NHH 7-105, Minneapolis, MN 55455 e-mail:
| | - Kerianne E Steucke
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, 312 Church Street SE NHH 7-105, Minneapolis, MN 55455 e-mail:
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota-Twin Cities, 420 Washington Avenue SE MCB 4-128, Minneapolis, MN 55455 e-mail:
| | - Victor H Barocas
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, 312 Church Street SE NHH 7-105, Minneapolis, MN 55455 e-mail:
| | - Patrick W Alford
- Department of Biomedical Engineering, University of Minnesota-Twin Cities, 312 Church Street SE NHH 7-105, Minneapolis, MN 55455 e-mail:
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140
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Tang Z, Hu Y, Wang Z, Jiang K, Zhan C, Marshall WF, Tang N. Mechanical Forces Program the Orientation of Cell Division during Airway Tube Morphogenesis. Dev Cell 2018; 44:313-325.e5. [PMID: 29337000 DOI: 10.1016/j.devcel.2017.12.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 11/13/2017] [Accepted: 12/12/2017] [Indexed: 11/16/2022]
Abstract
Oriented cell division plays a key role in controlling organogenesis. The mechanisms for regulating division orientation at the whole-organ level are only starting to become understood. By combining 3D time-lapse imaging, mouse genetics, and mathematical modeling, we find that global orientation of cell division is the result of a combination of two types of spindles with distinct spindle dynamic behaviors in the developing airway epithelium. Fixed spindles follow the classic long-axis rule and establish their division orientation before metaphase. In contrast, rotating spindles do not strictly follow the long-axis rule and determine their division orientation during metaphase. By using both a cell-based mechanical model and stretching-lung-explant experiments, we showed that mechanical force can function as a regulatory signal in maintaining the stable ratio between fixed spindles and rotating spindles. Our findings demonstrate that mechanical forces, cell geometry, and oriented cell division function together in a highly coordinated manner to ensure normal airway tube morphogenesis.
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Affiliation(s)
- Zan Tang
- College of Life Sciences, Peking University, Beijing 100871, China; National Institute of Biological Sciences, Beijing 102206, China
| | - Yucheng Hu
- Zhou Pei-yuan Center for Applied Mathematics, Tsinghua University, Beijing 100084, China
| | - Zheng Wang
- National Institute of Biological Sciences, Beijing 102206, China; Graduate School of Peking Union Medical College, Beijing 100730, China
| | - Kewu Jiang
- National Institute of Biological Sciences, Beijing 102206, China; College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Cheng Zhan
- National Institute of Biological Sciences, Beijing 102206, China
| | - Wallace F Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Nan Tang
- National Institute of Biological Sciences, Beijing 102206, China.
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141
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Ruiz-Herrero T, Alessandri K, Gurchenkov BV, Nassoy P, Mahadevan L. Organ size control via hydraulically gated oscillations. Development 2017; 144:4422-4427. [DOI: 10.1242/dev.153056] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 10/24/2017] [Indexed: 01/01/2023]
Abstract
Hollow vesicular tissues of various sizes and shapes arise in biological organs such as ears, guts, hearts, brains and even entire organisms. Regulating their size and shape is crucial for their function. Although chemical signaling has been thought to play a role in the regulation of cellular processes that feed into larger scales, it is increasingly recognized that mechanical forces are involved in the modulation of size and shape at larger length scales. Motivated by a variety of examples of tissue cyst formation and size control that show simultaneous growth and size oscillations, we create a minimal theoretical framework for the growth and dynamics of a soft, fluid-permeable, spherical shell. We show that these shells can relieve internal pressure by bursting intermittently, shrinking and re-growing, providing a simple mechanism by which hydraulically gated oscillations can regulate size. To test our theory, we develop an in vitro experimental set-up to monitor the growth and oscillations of a hollow tissue spheroid growing freely or when confined. A simple generalization of our theory to account for irreversible deformations allows us to explain the time scales and the amplitudes of oscillations in terms of the geometry and mechanical properties of the tissue shells. Taken together, our theory and experimental observations show how soft hydraulics can regulate the size of growing tissue shells.
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Affiliation(s)
- Teresa Ruiz-Herrero
- Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Kévin Alessandri
- Université de Bordeaux, Talence 33405, France
- Institut d'Optique Graduate School & CNRS, LP2N, Talence F-33405, France
| | - Basile V. Gurchenkov
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch-Graffenstaden, France
- Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch-Graffenstaden, France
- Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch-Graffenstaden, France
- Université de Strasbourg, 67404 Illkirch-Graffenstaden, France
| | - Pierre Nassoy
- Université de Bordeaux, Talence 33405, France
- Institut d'Optique Graduate School & CNRS, LP2N, Talence F-33405, France
| | - L. Mahadevan
- Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Departments of Physics and Organismic and Evolutionary Biology, Wyss Institute for BioInspired Engineering and Kavli Institute for NanoBio Science and Technology, Harvard University, Cambridge, MA 02138, USA
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142
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González-Valverde I, García-Aznar JM. A hybrid computational model to explore the topological characteristics of epithelial tissues. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2877. [PMID: 28249103 DOI: 10.1002/cnm.2877] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 02/22/2017] [Accepted: 02/26/2017] [Indexed: 06/06/2023]
Abstract
Epithelial tissues show a particular topology where cells resemble a polygon-like shape, but some biological processes can alter this tissue topology. During cell proliferation, mitotic cell dilation deforms the tissue and modifies the tissue topology. Additionally, cells are reorganized in the epithelial layer and these rearrangements also alter the polygon distribution. We present here a computer-based hybrid framework focused on the simulation of epithelial layer dynamics that combines discrete and continuum numerical models. In this framework, we consider topological and mechanical aspects of the epithelial tissue. Individual cells in the tissue are simulated by an off-lattice agent-based model, which keeps the information of each cell. In addition, we model the cell-cell interaction forces and the cell cycle. Otherwise, we simulate the passive mechanical behaviour of the cell monolayer using a material that approximates the mechanical properties of the cell. This continuum approach is solved by the finite element method, which uses a dynamic mesh generated by the triangulation of cell polygons. Forces generated by cell-cell interaction in the agent-based model are also applied on the finite element mesh. Cell movement in the agent-based model is driven by the displacements obtained from the deformed finite element mesh of the continuum mechanical approach. We successfully compare the results of our simulations with some experiments about the topology of proliferating epithelial tissues in Drosophila. Our framework is able to model the emergent behaviour of the cell monolayer that is due to local cell-cell interactions, which have a direct influence on the dynamics of the epithelial tissue.
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Affiliation(s)
- Ismael González-Valverde
- Department of Mechanical Engineering, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - José Manuel García-Aznar
- Department of Mechanical Engineering, Aragon Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
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143
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Cartagena-Rivera AX, Van Itallie CM, Anderson JM, Chadwick RS. Apical surface supracellular mechanical properties in polarized epithelium using noninvasive acoustic force spectroscopy. Nat Commun 2017; 8:1030. [PMID: 29044161 PMCID: PMC5715111 DOI: 10.1038/s41467-017-01145-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 08/18/2017] [Indexed: 11/24/2022] Open
Abstract
Maintenance of epithelial tissue integrity requires coordination between cell–cell adherens junctions, tight junctions (TJ), and the perijunctional actomyosin cytoskeleton. Here we addressed the hypothesis that alterations in TJ structure and remodeling of the actomyosin cytoskeleton modify epithelial mechanics. Current methods to measure supracellular mechanical properties disrupt intact monolayers, therefore, we developed a novel method using noncontact acoustic frequency-modulation atomic force microscopy (FM-AFM) and tested it on MDCK polarized monolayers. Our results show that double knockdown (dKD) of ZO-1/ZO-2 elevates the apical epithelial tension and effective viscosity. Interestingly, epithelial tension is more sensitive to inhibition of myosin II ATPase activity than to inhibition of ROCK activity, but viscosity is highly sensitive to both. Additionally, we showed epithelial intercellular pulling forces at tricellular junctions and adhesion forces in dKD cells are elevated with an increase in contractility. In conclusion, FM-AFM enables the physiological and quantitative investigation of mechanics in intact epithelium. Determination of apical tension, fluidity, and intercellular adhesive forces in an epithelial monolayer are currently disruptive. Here the authors present a method using acoustic force microscopy to measure changes in these parameters upon tight junction structural alterations in a MDCK monolayer.
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Affiliation(s)
- Alexander X Cartagena-Rivera
- Section on Auditory Mechanics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Christina M Van Itallie
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - James M Anderson
- Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Richard S Chadwick
- Section on Auditory Mechanics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.
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144
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Blanch-Mercader C, Casademunt J. Hydrodynamic instabilities, waves and turbulence in spreading epithelia. SOFT MATTER 2017; 13:6913-6928. [PMID: 28825077 DOI: 10.1039/c7sm01128h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a hydrodynamic model of spreading epithelial monolayers described as polar viscous fluids, with active contractility and traction on a substrate. The combination of both active forces generates an instability that leads to nonlinear traveling waves, which propagate in the direction of polarity with characteristic time scales that depend on contact forces. Our viscous fluid model provides a comprehensive understanding of a variety of observations on the slow dynamics of epithelial monolayers, remarkably those that seemed to be characteristic of elastic media. The model also makes simple predictions to test the non-elastic nature of the mechanical waves, and provides new insights into collective cell dynamics, explaining plithotaxis as a result of strong flow-polarity coupling, and quantifying the non-locality of force transmission. In addition, we study the nonlinear regime of waves deriving an exact map of the model into the complex Ginzburg-Landau equation, which provides a complete classification of possible nonlinear scenarios. In particular, we predict the transition to different forms of weak turbulence, which in turn could explain the chaotic dynamics often observed in epithelia.
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Affiliation(s)
- C Blanch-Mercader
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain. and Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS, 26 rue d' Ulm, 75005 Paris, France
| | - J Casademunt
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain. and Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, Barcelona, Spain
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145
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Guirao B, Bellaïche Y. Biomechanics of cell rearrangements in Drosophila. Curr Opin Cell Biol 2017; 48:113-124. [DOI: 10.1016/j.ceb.2017.06.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/05/2017] [Accepted: 06/24/2017] [Indexed: 10/19/2022]
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146
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Du V, Luciani N, Richard S, Mary G, Gay C, Mazuel F, Reffay M, Menasché P, Agbulut O, Wilhelm C. A 3D magnetic tissue stretcher for remote mechanical control of embryonic stem cell differentiation. Nat Commun 2017; 8:400. [PMID: 28900152 PMCID: PMC5596024 DOI: 10.1038/s41467-017-00543-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 07/06/2017] [Indexed: 12/11/2022] Open
Abstract
The ability to create a 3D tissue structure from individual cells and then to stimulate it at will is a major goal for both the biophysics and regenerative medicine communities. Here we show an integrated set of magnetic techniques that meet this challenge using embryonic stem cells (ESCs). We assessed the impact of magnetic nanoparticles internalization on ESCs viability, proliferation, pluripotency and differentiation profiles. We developed magnetic attractors capable of aggregating the cells remotely into a 3D embryoid body. This magnetic approach to embryoid body formation has no discernible impact on ESC differentiation pathways, as compared to the hanging drop method. It is also the base of the final magnetic device, composed of opposing magnetic attractors in order to form embryoid bodies in situ, then stretch them, and mechanically stimulate them at will. These stretched and cyclic purely mechanical stimulations were sufficient to drive ESCs differentiation towards the mesodermal cardiac pathway. The development of embryoid bodies that are responsive to external stimuli is of great interest in tissue engineering. Here, the authors culture embryonic stem cells with magnetic nanoparticles and show that the presence of magnetic fields could affect their aggregation and differentiation.
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Affiliation(s)
- Vicard Du
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - Nathalie Luciani
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - Sophie Richard
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - Gaëtan Mary
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - Cyprien Gay
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - François Mazuel
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - Myriam Reffay
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France
| | - Philippe Menasché
- Department of Cardiovascular Surgery, Hôpital Européen Georges Pompidou; Paris Cardiovascular Research Center, INSERM U970, Université Paris Descartes, Paris, 75015, France
| | - Onnik Agbulut
- Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine (IBPS), UMR CNRS 8256, Biological Adaptation and Ageing, 75005, Paris, France
| | - Claire Wilhelm
- Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057, CNRS and Université Paris Diderot, 75205, Paris Cedex 13, France.
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147
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Drebrin's Role in the Maintenance of Endothelial Integrity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:347-360. [PMID: 28865031 DOI: 10.1007/978-4-431-56550-5_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
The human endothelium forms a permeable barrier between the blood stream and surrounding tissues, strictly governing the passage of immune cells, fluids and metabolites. The regulation of cell-cell contact dynamics between endothelial cells is essential for this function and thus for the maintenance of vascular integrity. Intercellular adhesion within the endothelium is mainly dependent on adherens junctions, composed of cell-cell adhesion proteins such as VE-cadherin and nectin, and their associated proteins. Recent research points to a critical role of the actin cytoskeleton in endothelial integrity, by providing anchorage of adhesion complexes to the cell cortex. We could show that the F-actin-binding protein drebrin is a critical regulator of endothelial integrity, by linking nectin to the cortical actin cytoskeleton. In particular, the knockdown of drebrin leads to functional impairment of endothelial cells, characterized by rupturing of endothelial monolayers cultured under conditions mimicking vascular flow. This weakening of cell-cell contacts upon drebrin depletion is based on the destabilization of nectin at adherens junctions, followed by internalization and degradation in lysosomes. Conducting interaction studies, we showed that drebrin binds to nectin's interaction partner afadin, thus linking the nectin/afadin system to the cortical F-actin network. Drebrin, containing binding sites for both afadin and F-actin, is thus uniquely equipped to stabilize nectin at adherens junctions, thereby preserving endothelial integrity. Collectively, these results contribute to the current understanding of cell-cell junction regulation, introducing a new function of drebrin as a stabilizer of endothelial integrity.
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148
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Bhave G, Colon S, Ferrell N. The sulfilimine cross-link of collagen IV contributes to kidney tubular basement membrane stiffness. Am J Physiol Renal Physiol 2017; 313:F596-F602. [PMID: 28424209 PMCID: PMC5625101 DOI: 10.1152/ajprenal.00096.2017] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 12/12/2022] Open
Abstract
Basement membranes (BMs), a specialized form of extracellular matrix, underlie nearly all cell layers and provide structural support for tissues and interact with cell surface receptors to determine cell behavior. Both macromolecular composition and stiffness of the BM influence cell-BM interactions. Collagen IV is a major constituent of the BM that forms an extensively cross-linked oligomeric network. Its deficiency leads to BM mechanical instability, as observed with glomerular BM in Alport syndrome. These findings have led to the hypothesis that collagen IV and its cross-links determine BM stiffness. A sulfilimine bond (S = N) between a methionine sulfur and a lysine nitrogen cross-links collagen IV and is formed by the matrix enzyme peroxidasin. In peroxidasin knockout mice with reduced collagen IV sulfilimine cross-links, we find a reduction in renal tubular BM stiffness. Thus this work provides the first direct experimental evidence that collagen IV sulfilimine cross-links contribute to BM mechanical properties and provides a foundation for future work on the relationship of BM mechanics to cell function in renal disease.
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Affiliation(s)
- Gautam Bhave
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
| | - Selene Colon
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt Center for Kidney Disease, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Biological Sciences, Tennessee State University, Nashville, Tennessee; and
| | - Nicholas Ferrell
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee;
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149
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Hildebrand S, Hultin S, Subramani A, Petropoulos S, Zhang Y, Cao X, Mpindi J, Kalloniemi O, Johansson S, Majumdar A, Lanner F, Holmgren L. The E-cadherin/AmotL2 complex organizes actin filaments required for epithelial hexagonal packing and blastocyst hatching. Sci Rep 2017; 7:9540. [PMID: 28842668 PMCID: PMC5572699 DOI: 10.1038/s41598-017-10102-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/03/2017] [Indexed: 12/13/2022] Open
Abstract
Epithelial cells connect via cell-cell junctions to form sheets of cells with separate cellular compartments. These cellular connections are essential for the generation of cellular forms and shapes consistent with organ function. Tissue modulation is dependent on the fine-tuning of mechanical forces that are transmitted in part through the actin connection to E-cadherin as well as other components in the adherens junctions. In this report we show that p100 amotL2 forms a complex with E-cadherin that associates with radial actin filaments connecting cells over multiple layers. Genetic inactivation or depletion of amotL2 in epithelial cells in vitro or zebrafish and mouse in vivo, resulted in the loss of contractile actin filaments and perturbed epithelial packing geometry. We further showed that AMOTL2 mRNA and protein was expressed in the trophectoderm of human and mouse blastocysts. Genetic inactivation of amotL2 did not affect cellular differentiation but blocked hatching of the blastocysts from the zona pellucida. These results were mimicked by treatment with the myosin II inhibitor blebbistatin. We propose that the tension generated by the E-cadherin/AmotL2/actin filaments plays a crucial role in developmental processes such as epithelial geometrical packing as well as generation of forces required for blastocyst hatching.
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Affiliation(s)
- Sebastian Hildebrand
- Department of Clinical Sciences, Intervention and Technology (CLINTEC), Karolinska Institutet and Division of Obstetrics and Gynecology, Karolinska University Hospital, Huddinge, Sweden.,Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Sara Hultin
- Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Aravindh Subramani
- Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Sophie Petropoulos
- Department of Clinical Sciences, Intervention and Technology (CLINTEC), Karolinska Institutet and Division of Obstetrics and Gynecology, Karolinska University Hospital, Huddinge, Sweden
| | - Yuanyuan Zhang
- Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden
| | - Xiaofang Cao
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center (BMC), Uppsala University, Uppsala, Sweden
| | - John Mpindi
- Medical Biotechnology, VTT Technical Research Centre of Finland, Turku, Finland.,Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Olli Kalloniemi
- Medical Biotechnology, VTT Technical Research Centre of Finland, Turku, Finland.,Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Staffan Johansson
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center (BMC), Uppsala University, Uppsala, Sweden
| | - Arindam Majumdar
- Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden.,Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Fredrik Lanner
- Department of Clinical Sciences, Intervention and Technology (CLINTEC), Karolinska Institutet and Division of Obstetrics and Gynecology, Karolinska University Hospital, Huddinge, Sweden.
| | - Lars Holmgren
- Department of Oncology-Pathology, Cancer Centrum Karolinska (CCK), Karolinska Institutet, Stockholm, Sweden.
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150
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Stockinger P, Solon J. Tissue Morphogenesis: Take a Step Back and Relax! Curr Biol 2017; 27:R813-R815. [PMID: 28829970 DOI: 10.1016/j.cub.2017.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A recent study identified a molecular mechanism responsible for the relaxation of epithelia upon stretch. This relaxation is due to the activity of cytohesins, which locally inhibit actomyosin contractility at cellular junctions.
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Affiliation(s)
- Petra Stockinger
- Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
| | - Jérôme Solon
- Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain.
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