101
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Actomyosin pulsation and flows in an active elastomer with turnover and network remodeling. Nat Commun 2017; 8:1121. [PMID: 29066711 PMCID: PMC5783953 DOI: 10.1038/s41467-017-01130-1] [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: 04/05/2016] [Accepted: 08/22/2017] [Indexed: 02/03/2023] Open
Abstract
Tissue remodeling requires cell shape changes associated with pulsation and flow of the actomyosin cytoskeleton. Here we describe the hydrodynamics of actomyosin as a confined active elastomer with turnover of its components. Our treatment is adapted to describe the diversity of contractile dynamical regimes observed in vivo. When myosin-induced contractile stresses are low, the deformations of the active elastomer are affine and exhibit spontaneous oscillations, propagating waves, contractile collapse and spatiotemporal chaos. We study the nucleation, growth and coalescence of actomyosin-dense regions that, beyond a threshold, spontaneously move as a spatially localized traveling front. Large myosin-induced contractile stresses lead to nonaffine deformations due to enhanced actin and crosslinker turnover. This results in a transient actin network that is constantly remodeling and naturally accommodates intranetwork flows of the actomyosin-dense regions. We verify many predictions of our study in Drosophila embryonic epithelial cells undergoing neighbor exchange during germband extension. Tissue remodeling involves substantial involvement of the contractile actomyosin cytoskeleton. Here the authors model the spatiotemporal evolution of actomyosin densities during Drosophila germband extension and find affine and nonaffine deformations that depend on the magnitude of local contractile stress.
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102
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Naganathan SR, Oates AC. Mechanochemical coupling and developmental pattern formation. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.coisb.2017.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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103
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Viscoelastic Dissipation Stabilizes Cell Shape Changes during Tissue Morphogenesis. Curr Biol 2017; 27:3132-3142.e4. [DOI: 10.1016/j.cub.2017.09.005] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/27/2017] [Accepted: 09/05/2017] [Indexed: 12/22/2022]
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104
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Integrating planar polarity and tissue mechanics in computational models of epithelial morphogenesis. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.coisb.2017.07.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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105
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Dumbali SP, Mei L, Qian S, Maruthamuthu V. Endogenous Sheet-Averaged Tension Within a Large Epithelial Cell Colony. J Biomech Eng 2017; 139:2646921. [PMID: 28753694 DOI: 10.1115/1.4037404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Indexed: 11/08/2022]
Abstract
Epithelial cells form quasi-two-dimensional sheets that function as contractile media to effect tissue shape changes during development and homeostasis. Endogenously generated intrasheet tension is a driver of such changes, but has predominantly been measured in the presence of directional migration. The nature of epithelial cell-generated forces transmitted over supracellular distances, in the absence of directional migration, is thus largely unclear. In this report, we consider large epithelial cell colonies which are archetypical multicell collectives with extensive cell-cell contacts but with a symmetric (circular) boundary. Using the traction force imbalance method (TFIM) (traction force microscopy combined with physical force balance), we first show that one can determine the colony-level endogenous sheet forces exerted at the midline by one half of the colony on the other half with no prior assumptions on the uniformity of the mechanical properties of the cell sheet. Importantly, we find that this colony-level sheet force exhibits large variations with orientation-the difference between the maximum and minimum sheet force is comparable to the average sheet force itself. Furthermore, the sheet force at the colony midline is largely tensile but the shear component exhibits significantly more variation with orientation. We thus show that even an unperturbed epithelial colony with a symmetric boundary shows significant directional variation in the endogenous sheet tension and shear forces that subsist at the colony level.
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Affiliation(s)
- Sandeep P Dumbali
- Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529
| | - Lanju Mei
- Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529
| | - Shizhi Qian
- Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529
| | - Venkat Maruthamuthu
- Mechanical and Aerospace Engineering, Old Dominion University, 4635 Hampton Boulevard, 238e Kaufman, Norfolk, VA 23529 e-mail:
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106
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Harlepp S, Thalmann F, Follain G, Goetz JG. Hemodynamic forces can be accurately measured in vivo with optical tweezers. Mol Biol Cell 2017; 28:3252-3260. [PMID: 28904205 PMCID: PMC5687027 DOI: 10.1091/mbc.e17-06-0382] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/15/2022] Open
Abstract
Force sensing and generation at the tissue and cellular scale is central to many biological events. There is a growing interest in modern cell biology for methods enabling force measurements in vivo. Optical trapping allows noninvasive probing of piconewton forces and thus emerged as a promising mean for assessing biomechanics in vivo. Nevertheless, the main obstacles lie in the accurate determination of the trap stiffness in heterogeneous living organisms, at any position where the trap is used. A proper calibration of the trap stiffness is thus required for performing accurate and reliable force measurements in vivo. Here we introduce a method that overcomes these difficulties by accurately measuring hemodynamic profiles in order to calibrate the trap stiffness. Doing so, and using numerical methods to assess the accuracy of the experimental data, we measured flow profiles and drag forces imposed to trapped red blood cells of living zebrafish embryos. Using treatments enabling blood flow tuning, we demonstrated that such a method is powerful in measuring hemodynamic forces in vivo with accuracy and confidence. Altogether this study demonstrates the power of optical tweezing in measuring low range hemodynamic forces in vivo and offers an unprecedented tool in both cell and developmental biology.
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Affiliation(s)
- Sébastien Harlepp
- Université de Strasbourg, 67000 Strasbourg, France .,IPCMS, UMR7504, 67200 Strasbourg, France.,LabEx NIE, Université de Strasbourg, 67000 Strasbourg, France
| | - Fabrice Thalmann
- Université de Strasbourg, 67000 Strasbourg, France.,ICS, UPR22, 67034 Strasbourg, France
| | - Gautier Follain
- Université de Strasbourg, 67000 Strasbourg, France.,Inserm UMR_S1109, MN3T, 67200 Strasbourg, France.,LabEx Medalis, Université de Strasbourg, 67000 Strasbourg, France.,Fédération de Médecine Translationnelle de Strasbourg (FMTS), 67000 Strasbourg, France
| | - Jacky G Goetz
- Université de Strasbourg, 67000 Strasbourg, France .,Inserm UMR_S1109, MN3T, 67200 Strasbourg, France.,LabEx Medalis, Université de Strasbourg, 67000 Strasbourg, France.,Fédération de Médecine Translationnelle de Strasbourg (FMTS), 67000 Strasbourg, France
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107
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Ishihara S, Marcq P, Sugimura K. From cells to tissue: A continuum model of epithelial mechanics. Phys Rev E 2017; 96:022418. [PMID: 28950595 DOI: 10.1103/physreve.96.022418] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Indexed: 01/05/2023]
Abstract
A two-dimensional continuum model of epithelial tissue mechanics was formulated using cellular-level mechanical ingredients and cell morphogenetic processes, including cellular shape changes and cellular rearrangements. This model incorporates stress and deformation tensors, which can be compared with experimental data. Focusing on the interplay between cell shape changes and cell rearrangements, we elucidated dynamical behavior underlying passive relaxation, active contraction-elongation, and tissue shear flow, including a mechanism for contraction-elongation, whereby tissue flows perpendicularly to the axis of cell elongation. This study provides an integrated scheme for the understanding of the orchestration of morphogenetic processes in individual cells to achieve epithelial tissue morphogenesis.
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Affiliation(s)
- Shuji Ishihara
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan and Department of Physics, School of Science and Technology, Meiji University, Kanagawa 214-8571, Japan
| | - Philippe Marcq
- Sorbonne Universités, UPMC Université Paris 6, Institut Curie, CNRS, UMR 168, Laboratoire Physico Chimie Curie, Paris, France
| | - Kaoru Sugimura
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan and JST PRESTO, Tokyo 102-0075, Japan
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108
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An Actomyosin-Arf-GEF Negative Feedback Loop for Tissue Elongation under Stress. Curr Biol 2017; 27:2260-2270.e5. [DOI: 10.1016/j.cub.2017.06.038] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/15/2017] [Accepted: 06/14/2017] [Indexed: 02/06/2023]
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109
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Raghunathan R, Zhang J, Wu C, Rippy J, Singh M, Larin KV, Scarcelli G. Evaluating biomechanical properties of murine embryos using Brillouin microscopy and optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-6. [PMID: 28861955 PMCID: PMC5582619 DOI: 10.1117/1.jbo.22.8.086013] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/03/2017] [Indexed: 05/19/2023]
Abstract
Embryogenesis is regulated by numerous changes in mechanical properties of the cellular microenvironment. Thus, studying embryonic mechanophysiology can provide a more thorough perspective of embryonic development, potentially improving early detection of congenital abnormalities as well as evaluating and developing therapeutic interventions. A number of methods and techniques have been used to study cellular biomechanical properties during embryogenesis. While some of these techniques are invasive or involve the use of external agents, others are compromised in terms of spatial and temporal resolutions. We propose the use of Brillouin microscopy in combination with optical coherence tomography (OCT) to measure stiffness as well as structural changes in a developing embryo. While Brillouin microscopy assesses the changes in stiffness among different organs of the embryo, OCT provides the necessary structural guidance.
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Affiliation(s)
- Raksha Raghunathan
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Jitao Zhang
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
| | - Chen Wu
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Justin Rippy
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Manmohan Singh
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
| | - Kirill V. Larin
- University of Houston, Department of Biomedical Engineering, Houston, Texas, United States
- Tomsk State University, Interdisciplinary Laboratory of Biophotonics, Tomsk, Russia
- Address all correspondence to: Kirill V. Larin, E-mail: ; Giuliano Scarcelli, E-mail:
| | - Giuliano Scarcelli
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
- Address all correspondence to: Kirill V. Larin, E-mail: ; Giuliano Scarcelli, E-mail:
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110
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Quantitative modelling of epithelial morphogenesis: integrating cell mechanics and molecular dynamics. Semin Cell Dev Biol 2017; 67:153-160. [DOI: 10.1016/j.semcdb.2016.07.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/28/2016] [Accepted: 07/27/2016] [Indexed: 12/22/2022]
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111
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Hara Y. Contraction and elongation: Mechanics underlying cell boundary deformations in epithelial tissue. Dev Growth Differ 2017; 59:340-350. [DOI: 10.1111/dgd.12356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/02/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Yusuke Hara
- Mechanobiology Institute National University of Singapore T‐Lab 5A Engineering Drive 1, Level 9 Singapore 117411
- Temasek Life Sciences Laboratory National University of Singapore 1 Research Link Singapore 117604 Singapore
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112
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Alt S, Ganguly P, Salbreux G. Vertex models: from cell mechanics to tissue morphogenesis. Philos Trans R Soc Lond B Biol Sci 2017; 372:20150520. [PMID: 28348254 PMCID: PMC5379026 DOI: 10.1098/rstb.2015.0520] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2016] [Indexed: 12/23/2022] Open
Abstract
Tissue morphogenesis requires the collective, coordinated motion and deformation of a large number of cells. Vertex model simulations for tissue mechanics have been developed to bridge the scales between force generation at the cellular level and tissue deformation and flows. We review here various formulations of vertex models that have been proposed for describing tissues in two and three dimensions. We discuss a generic formulation using a virtual work differential, and we review applications of vertex models to biological morphogenetic processes. We also highlight recent efforts to obtain continuum theories of tissue mechanics, which are effective, coarse-grained descriptions of vertex models.This article is part of the themed issue 'Systems morphodynamics: understanding the development of tissue hardware'.
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Affiliation(s)
- Silvanus Alt
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Poulami Ganguly
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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113
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Davidson LA. Mechanical design in embryos: mechanical signalling, robustness and developmental defects. Philos Trans R Soc Lond B Biol Sci 2017; 372:20150516. [PMID: 28348252 PMCID: PMC5379024 DOI: 10.1098/rstb.2015.0516] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2016] [Indexed: 12/18/2022] Open
Abstract
Embryos are shaped by the precise application of force against the resistant structures of multicellular tissues. Forces may be generated, guided and resisted by cells, extracellular matrix, interstitial fluids, and how they are organized and bound within the tissue's architecture. In this review, we summarize our current thoughts on the multiple roles of mechanics in direct shaping, mechanical signalling and robustness of development. Genetic programmes of development interact with environmental cues to direct the composition of the early embryo and endow cells with active force production. Biophysical advances now provide experimental tools to measure mechanical resistance and collective forces during morphogenesis and are allowing integration of this field with studies of signalling and patterning during development. We focus this review on concepts that highlight this integration, and how the unique contributions of mechanical cues and gradients might be tested side by side with conventional signalling systems. We conclude with speculation on the integration of large-scale programmes of development, and how mechanical responses may ensure robust development and serve as constraints on programmes of tissue self-assembly.This article is part of the themed issue 'Systems morphodynamics: understanding the development of tissue hardware'.
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Affiliation(s)
- Lance A Davidson
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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114
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Boyd ARB, Moore S, Sader JE, Lee PVS. Modelling apical columnar epithelium mechanics from circumferential contractile fibres. Biomech Model Mechanobiol 2017; 16:1555-1568. [PMID: 28389829 DOI: 10.1007/s10237-017-0905-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 03/27/2017] [Indexed: 11/26/2022]
Abstract
Simple columnar epithelia are formed by individual epithelial cells connecting together to form single cell high sheets. They are a main component of many important body tissues and are heavily involved in both normal and cancerous cell activities. Prior experimental observations have identified a series of contractile fibres around the circumference of a cross section located in the upper (apical) region of each cell. While other potential mechanisms have been identified in both the experimental and theoretical literature, these circumferential fibres are considered to be the most likely mechanism controlling movement of this cross section. Here, we investigated the impact of circumferential contractile fibres on movement of the cross section by creating an alternate model where movement is driven from circumferential contractile fibres, without any other potential mechanisms. In this model, we utilised a circumferential contractile fibre representation based on investigations into the movement of contractile fibres as an individual system, treated circumferential fibres as a series of units, and matched our model simulation to experimental geometries. By testing against laser ablation datasets sourced from existing literature, we found that circumferential fibres can reproduce the majority of cross-sectional movements. We also investigated model predictions related to various aspects of cross-sectional movement, providing insights into epithelium mechanics and demonstrating the usefulness of our modelling approach.
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Affiliation(s)
- A R B Boyd
- Department of Mechanical Engineering, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - S Moore
- IBM Research Australia, Level 5, 204 Lygon Street, Carlton, VIC, 3010, Australia
| | - J E Sader
- School of Mathematics and Statistics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - P V S Lee
- Department of Mechanical Engineering, University of Melbourne, Melbourne, VIC, 3010, Australia.
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115
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Ghosh S, Cimino JG, Scott AK, Damen FW, Phillips EH, Veress AI, Neu CP, Goergen CJ. In Vivo Multiscale and Spatially-Dependent Biomechanics Reveals Differential Strain Transfer Hierarchy in Skeletal Muscle. ACS Biomater Sci Eng 2017; 3:2798-2805. [PMID: 29276759 DOI: 10.1021/acsbiomaterials.6b00772] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biological tissues have a complex hierarchical architecture that spans organ to subcellular scales and comprises interconnected biophysical and biochemical machinery. Mechanotransduction, gene regulation, gene protection, and structure-function relationships in tissues depend on how force and strain are modulated from macro to micro scales, and vice versa. Traditionally, computational and experimental techniques have been used in common model systems (e.g., embryos) and simple strain measures were applied. But the hierarchical transfer of mechanical parameters like strain in mammalian systems is largely unexplored in vivo. Here, we experimentally probed complex strain transfer processes in mammalian skeletal muscle tissue over multiple biological scales using complementary in vivo ultrasound and optical imaging approaches. An iterative hyperelastic warping technique quantified the spatially-dependent strain distributions in tissue, matrix, and subcellular (nuclear) structures, and revealed a surprising increase in strain magnitude and heterogeneity in active muscle as the spatial scale also increased. The multiscale strain heterogeneity indicates tight regulation of mechanical signals to the nuclei of individual cells in active muscle, and an emergent behavior appearing at larger (e.g. tissue) scales characterized by dramatically increased strain complexity.
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Affiliation(s)
- Soham Ghosh
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States
| | - James G Cimino
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, West Lafayette, Indiana 47907, United States
| | - Adrienne K Scott
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States
| | - Frederick W Damen
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, West Lafayette, Indiana 47907, United States
| | - Evan H Phillips
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, West Lafayette, Indiana 47907, United States
| | - Alexander I Veress
- Department of Mechanical Engineering, University of Washington, 352600 Stevens Way, Seattle, Washington 98195, United States
| | - Corey P Neu
- Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States.,Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, West Lafayette, Indiana 47907, United States
| | - Craig J Goergen
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, West Lafayette, Indiana 47907, United States
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116
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Kobb AB, Zulueta-Coarasa T, Fernandez-Gonzalez R. Tension regulates myosin dynamics during Drosophila embryonic wound repair. J Cell Sci 2017; 130:689-696. [DOI: 10.1242/jcs.196139] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/03/2017] [Indexed: 12/14/2022] Open
Abstract
ABSTRACT
Embryos repair epithelial wounds rapidly in a process driven by collective cell movements. Upon wounding, actin and the molecular motor non-muscle myosin II are redistributed in the cells adjacent to the wound, forming a supracellular purse string around the lesion. Purse string contraction coordinates cell movements and drives rapid wound closure. By using fluorescence recovery after photobleaching in Drosophila embryos, we found that myosin turns over as the purse string contracts. Myosin turnover at the purse string was slower than in other actomyosin networks that had a lower level of contractility. Mathematical modelling suggested that myosin assembly and disassembly rates were both reduced by tension at the wound edge. We used laser ablation to show that tension at the purse string increased as wound closure progressed, and that the increase in tension was associated with reduced myosin turnover. Reducing purse string tension by laser-mediated severing resulted in increased turnover and loss of myosin. Finally, myosin motor activity was necessary for its stabilization around the wound and for rapid wound closure. Our results indicate that mechanical forces regulate myosin dynamics during embryonic wound repair.
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Affiliation(s)
- Anna B. Kobb
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada M5G 1M1
| | - Teresa Zulueta-Coarasa
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada M5G 1M1
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Ontario, Canada M5G 1M1
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada M5S 3G5
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
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117
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Serwane F, Mongera A, Rowghanian P, Kealhofer DA, Lucio AA, Hockenbery ZM, Campàs O. In vivo quantification of spatially varying mechanical properties in developing tissues. Nat Methods 2017; 14:181-186. [PMID: 27918540 PMCID: PMC5524219 DOI: 10.1038/nmeth.4101] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 10/23/2016] [Indexed: 12/13/2022]
Abstract
The mechanical properties of the cellular microenvironment and their spatiotemporal variations are thought to play a central role in sculpting embryonic tissues, maintaining organ architecture and controlling cell behavior, including cell differentiation. However, no direct in vivo and in situ measurement of mechanical properties within developing 3D tissues and organs has yet been performed. Here we introduce a technique that employs biocompatible, magnetically responsive ferrofluid microdroplets as local mechanical actuators and allows quantitative spatiotemporal measurements of mechanical properties in vivo. Using this technique, we show that vertebrate body elongation entails spatially varying tissue mechanics along the anteroposterior axis. Specifically, we find that the zebrafish tailbud is viscoelastic (elastic below a few seconds and fluid after just 1 min) and displays decreasing stiffness and increasing fluidity toward its posterior elongating region. This method opens new avenues to study mechanobiology in vivo, both in embryogenesis and in disease processes, including cancer.
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Affiliation(s)
- Friedhelm Serwane
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
| | - Alessandro Mongera
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
| | - Payam Rowghanian
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
| | - David A. Kealhofer
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Adam A. Lucio
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
| | - Zachary M. Hockenbery
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
| | - Otger Campàs
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
- California NanoSystems Institute, University of California, Santa Barbara, CA, USA
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA, USA
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118
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Zulueta-Coarasa T, Fernandez-Gonzalez R. Tension (re)builds: Biophysical mechanisms of embryonic wound repair. Mech Dev 2016; 144:43-52. [PMID: 27989746 DOI: 10.1016/j.mod.2016.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/15/2016] [Accepted: 11/18/2016] [Indexed: 12/24/2022]
Abstract
Embryonic tissues display an outstanding ability to rapidly repair wounds. Epithelia, in particular, serve as protective layers that line internal organs and form the skin. Thus, maintenance of epithelial integrity is of utmost importance for animal survival, particularly at embryonic stages, when an immune system has not yet fully developed. Rapid embryonic repair of epithelial tissues is conserved across species, and involves the collective migration of the cells around the wound. The migratory cell behaviours associated with wound repair require the generation and transmission of mechanical forces, not only for the cells to move, but also to coordinate their movements. Here, we review the forces involved in embryonic wound repair. We discuss how different force-generating structures are assembled at the molecular level, and the mechanisms that maintain the balance between force-generating structures as wounds close. Finally, we describe the mechanisms that cells use to coordinate the generation of mechanical forces around the wound. Collective cell movements and their misregulation have been associated with defective tissue repair, developmental abnormalities and cancer metastasis. Thus, we propose that understanding the role of mechanical forces during embryonic wound closure will be crucial to develop therapeutic interventions that promote or prevent collective cell movements under pathological conditions.
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Affiliation(s)
- Teresa Zulueta-Coarasa
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Ted Rogers Centre for Heart Research, University of Toronto, Toronto, ON M5G 1M1, Canada; Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.
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119
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Hou J, Luo T, Ng KL, Leung AYH, Liang R, Sun D. Characterization of Drug Effect on Leukemia Cells Through Single Cell Assay With Optical Tweezers and Dielectrophoresis. IEEE Trans Nanobioscience 2016; 15:820-827. [DOI: 10.1109/tnb.2016.2616160] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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120
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Coburn L, Lopez H, Caldwell BJ, Moussa E, Yap C, Priya R, Noppe A, Roberts AP, Lobaskin V, Yap AS, Neufeld Z, Gomez GA. Contact inhibition of locomotion and mechanical cross-talk between cell-cell and cell-substrate adhesion determine the pattern of junctional tension in epithelial cell aggregates. Mol Biol Cell 2016; 27:3436-3448. [PMID: 27605701 PMCID: PMC5221537 DOI: 10.1091/mbc.e16-04-0226] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/30/2016] [Indexed: 01/13/2023] Open
Abstract
A computational approach is used to analyze the biomechanics of epithelial cells based on their capacity to adhere to one another and to the substrate and exhibit contact inhibition of locomotion. This approach reproduces emergent properties of epithelial cell aggregates and makes predictions for experimental validation. We used a computational approach to analyze the biomechanics of epithelial cell aggregates—islands, stripes, or entire monolayers—that combines both vertex and contact-inhibition-of-locomotion models to include cell–cell and cell–substrate adhesion. Examination of the distribution of cell protrusions (adhesion to the substrate) in the model predicted high-order profiles of cell organization that agree with those previously seen experimentally. Cells acquired an asymmetric distribution of basal protrusions, traction forces, and apical aspect ratios that decreased when moving from the edge to the island center. Our in silico analysis also showed that tension on cell–cell junctions and apical stress is not homogeneous across the island. Instead, these parameters are higher at the island center and scale up with island size, which we confirmed experimentally using laser ablation assays and immunofluorescence. Without formally being a three-dimensional model, our approach has the minimal elements necessary to reproduce the distribution of cellular forces and mechanical cross-talk, as well as the distribution of principal stress in cells within epithelial cell aggregates. By making experimentally testable predictions, our approach can aid in mechanical analysis of epithelial tissues, especially when local changes in cell–cell and/or cell–substrate adhesion drive collective cell behavior.
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Affiliation(s)
- Luke Coburn
- School of Physics and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland .,Institute of Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen AB24 3FX, United Kingdom
| | - Hender Lopez
- School of Physics and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland.,Center for BioNano Interactions, School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Benjamin J Caldwell
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Elliott Moussa
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Chloe Yap
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Rashmi Priya
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Adrian Noppe
- School of Mathematics and Physics, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Anthony P Roberts
- School of Mathematics and Physics, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Vladimir Lobaskin
- School of Physics and Complex and Adaptive Systems Laboratory, University College Dublin, Belfield, Dublin 4, Ireland
| | - Alpha S Yap
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Zoltan Neufeld
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia.,School of Mathematics and Physics, University of Queensland, St. Lucia, Brisbane 4072, Australia
| | - Guillermo A Gomez
- Institute for Molecular Bioscience, Division of Cell Biology and Molecular Medicine, University of Queensland, St. Lucia, Brisbane 4072, Australia
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121
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de Saint Vincent MR. Optical twisting to monitor the rheology of single cells. Biorheology 2016; 53:69-80. [DOI: 10.3233/bir-15084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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122
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Liu AP. Biophysical Tools for Cellular and Subcellular Mechanical Actuation of Cell Signaling. Biophys J 2016; 111:1112-1118. [PMID: 27456131 DOI: 10.1016/j.bpj.2016.02.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/17/2016] [Accepted: 02/01/2016] [Indexed: 10/24/2022] Open
Abstract
The ability to spatially control cell signaling can help resolve fundamental biological questions. Optogenetic and chemical dimerization techniques along with fluorescent biosensors to report cell signaling activities have enabled researchers to both visualize and perturb biochemistry in living cells. A number of approaches based on mechanical actuation using force-field gradients have emerged as complementary technologies to manipulate cell signaling in real time. This review covers several technologies, including optical, magnetic, and acoustic control of cell signaling and behavior and highlights some studies that have led to novel insights. I will also discuss some future direction on repurposing mechanosensitive channel for mechanical actuation of spatial cell signaling.
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Affiliation(s)
- Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan; Biophysics Program, University of Michigan, Ann Arbor, Michigan.
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123
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Campàs O. A toolbox to explore the mechanics of living embryonic tissues. Semin Cell Dev Biol 2016; 55:119-30. [PMID: 27061360 PMCID: PMC4903887 DOI: 10.1016/j.semcdb.2016.03.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/15/2016] [Indexed: 01/03/2023]
Abstract
The sculpting of embryonic tissues and organs into their functional morphologies involves the spatial and temporal regulation of mechanics at cell and tissue scales. Decades of in vitro work, complemented by some in vivo studies, have shown the relevance of mechanical cues in the control of cell behaviors that are central to developmental processes, but the lack of methodologies enabling precise, quantitative measurements of mechanical cues in vivo have hindered our understanding of the role of mechanics in embryonic development. Several methodologies are starting to enable quantitative studies of mechanics in vivo and in situ, opening new avenues to explore how mechanics contributes to shaping embryonic tissues and how it affects cell behavior within developing embryos. Here we review the present methodologies to study the role of mechanics in living embryonic tissues, considering their strengths and drawbacks as well as the conditions in which they are most suitable.
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Affiliation(s)
- Otger Campàs
- Department of Mechanical Engineering, University of California, Santa Barbara, CA 93106, USA; Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, CA 93106, USA; California Nanosystems Institute, University of California, Santa Barbara, CA 93106, USA.
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124
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Abstract
Development, homeostasis and regeneration of tissues result from a complex combination of genetics and mechanics, and progresses in the former have been quicker than in the latter. Measurements of in situ forces and stresses appear to be increasingly important to delineate the role of mechanics in development. We review here several emerging techniques: contact manipulation, manipulation using light, visual sensors, and non-mechanical observation techniques. We compare their fields of applications, their advantages and limitations, and their validations. These techniques complement measurements of deformations and of mechanical properties. We argue that such approaches could have a significant impact on our understanding of the development of living tissues in the near future.
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Affiliation(s)
- Kaoru Sugimura
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), iCeMS Complex 2, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501, Japan JST, PRESTO, 5 Sanban-cho, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Pierre-François Lenne
- Institut de Biologie du Développement de Marseille, Aix-Marseille Université, CNRS UMR7288, Case 907, Parc Scientifique de Luminy, F-13288 Marseille Cedex 9, France
| | - François Graner
- Laboratoire Matière et Systémes Complexes, Université Denis Diderot - Paris 7, CNRS UMR7057, 10 rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13, France
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125
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Murisic N, Hakim V, Kevrekidis IG, Shvartsman SY, Audoly B. From discrete to continuum models of three-dimensional deformations in epithelial sheets. Biophys J 2016; 109:154-63. [PMID: 26153712 DOI: 10.1016/j.bpj.2015.05.019] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 04/13/2015] [Accepted: 05/13/2015] [Indexed: 11/28/2022] Open
Abstract
Epithelial tissue, in which cells adhere tightly to each other and to the underlying substrate, is one of the four major tissue types in adult organisms. In embryos, epithelial sheets serve as versatile substrates during the formation of developing organs. Some aspects of epithelial morphogenesis can be adequately described using vertex models, in which the two-dimensional arrangement of epithelial cells is approximated by a polygonal lattice with an energy that has contributions reflecting the properties of individual cells and their interactions. Previous studies with such models have largely focused on dynamics confined to two spatial dimensions and analyzed them numerically. We show how these models can be extended to account for three-dimensional deformations and studied analytically. Starting from the extended model, we derive a continuum plate description of cell sheets, in which the effective tissue properties, such as bending rigidity, are related explicitly to the parameters of the vertex model. To derive the continuum plate model, we duly take into account a microscopic shift between the two sublattices of the hexagonal network, which has been ignored in previous work. As an application of the continuum model, we analyze tissue buckling by a line tension applied along a circular contour, a simplified set-up relevant to several situations in the developmental contexts. The buckling thresholds predicted by the continuum description are in good agreement with the results of stability calculations based on the vertex model. Our results establish a direct connection between discrete and continuum descriptions of cell sheets and can be used to probe a wide range of morphogenetic processes in epithelial tissues.
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Affiliation(s)
- Nebojsa Murisic
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Vincent Hakim
- CNRS & Laboratoire de Physique Statistique, Ecole Normale Supérieure, Paris, France
| | - Ioannis G Kevrekidis
- Chemical and Biological Engineering, Princeton University, Princeton, New Jersey
| | - Stanislav Y Shvartsman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Basile Audoly
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7190 Institut Jean Le Rond d'Alembert, Paris, France.
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126
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Kannan N, Tang VW. Synaptopodin couples epithelial contractility to α-actinin-4-dependent junction maturation. J Cell Biol 2016; 211:407-34. [PMID: 26504173 PMCID: PMC4621826 DOI: 10.1083/jcb.201412003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A novel tension-sensitive junctional protein, synaptopodin, can relay biophysical input from cellular actomyosin contractility to induce biochemical changes at cell–cell contacts, resulting in structural reorganization of the junctional complex and epithelial barrier maturation. The epithelial junction experiences mechanical force exerted by endogenous actomyosin activities and from interactions with neighboring cells. We hypothesize that tension generated at cell–cell adhesive contacts contributes to the maturation and assembly of the junctional complex. To test our hypothesis, we used a hydraulic apparatus that can apply mechanical force to intercellular junction in a confluent monolayer of cells. We found that mechanical force induces α-actinin-4 and actin accumulation at the cell junction in a time- and tension-dependent manner during junction development. Intercellular tension also induces α-actinin-4–dependent recruitment of vinculin to the cell junction. In addition, we have identified a tension-sensitive upstream regulator of α-actinin-4 as synaptopodin. Synaptopodin forms a complex containing α-actinin-4 and β-catenin and interacts with myosin II, indicating that it can physically link adhesion molecules to the cellular contractile apparatus. Synaptopodin depletion prevents junctional accumulation of α-actinin-4, vinculin, and actin. Knockdown of synaptopodin and α-actinin-4 decreases the strength of cell–cell adhesion, reduces the monolayer permeability barrier, and compromises cellular contractility. Our findings underscore the complexity of junction development and implicate a control process via tension-induced sequential incorporation of junctional components.
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Affiliation(s)
- Nivetha Kannan
- Program in Global Public Health, University of Illinois, Urbana-Champaign, Champaign, IL 61801
| | - Vivian W Tang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Champaign, IL 61801
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127
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Vasquez CG, Martin AC. Force transmission in epithelial tissues. Dev Dyn 2016; 245:361-71. [PMID: 26756938 DOI: 10.1002/dvdy.24384] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/10/2015] [Accepted: 12/31/2015] [Indexed: 12/12/2022] Open
Abstract
In epithelial tissues, cells constantly generate and transmit forces between each other. Forces generated by the actomyosin cytoskeleton regulate tissue shape and structure and also provide signals that influence cells' decisions to divide, die, or differentiate. Forces are transmitted across epithelia because cells are mechanically linked through junctional complexes, and forces can propagate through the cell cytoplasm. Here, we review some of the molecular mechanisms responsible for force generation, with a specific focus on the actomyosin cortex and adherens junctions. We then discuss evidence for how these mechanisms promote cell shape changes and force transmission in tissues.
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Affiliation(s)
- Claudia G Vasquez
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts
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128
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Liang X, Michael M, Gomez GA. Measurement of Mechanical Tension at Cell-cell Junctions Using Two-photon Laser Ablation. Bio Protoc 2016; 6:e2068. [PMID: 28191488 DOI: 10.21769/bioprotoc.2068] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The cortical actomyosin cytoskeleton is found in all non-muscle cells where a key function is to control mechanical force (Salbreux et al., 2012). When coupled to E-cadherin cell-cell adhesion, cortical actomyosin generates junctional tension that influences many aspects of tissue function, organization and morphogenesis (Lecuit and Yap, 2015). Uncovering the molecular mechanisms underlying the generation of junctional tension requires tools for measuring it in live cells with a high spatio-temporal resolution. For this, we have set up a technique of laser ablation, in which we use the high power output of a two-photon laser to physically cut the actin cortex at the sites of cell-cell adhesion labeled with E-cadherin-GFP. Tension, thus is visualized as the outwards recoil of the vertices that define a junction after this was ablated/cut. Analysis of recoil versus time allows extracting parameters related to the amount of contractile force that is applied to the junction before ablation (initial recoil) and the ratio between elasticity of the junction and viscosity of the media (cytoplasm) in which the junctional cortex is immersed. Using this approach we have discovered how Src protein-tyrosine kinase (Gomez et al., 2015); actin-binding proteins such as tropomyosins (Caldwell et al., 2014) and N-WASP (Wu et al., 2014); Myosin II (Priya et al., 2015) and coronin-1B (Michael et al., 2016) contribute to the molecular apparatus responsible for generating tension at the cell-cell junctions. This protocol describes the experimental procedure for setting up laser ablation experiments and how to optimize ablation and acquisition conditions for optimal measurements of junctional tension. It also provides a full description, step by step, of the post-acquisition analysis required to evaluate changes in contractile force as well as cell elasticity and/or cytoplasm viscosity.
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Affiliation(s)
- Xuan Liang
- Divisions of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Australia
| | - Magdalene Michael
- Randall Division of Cell and Molecular Biophysics, King's College London, Guy's Campus, London, UK
| | - Guillermo A Gomez
- Divisions of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Australia
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129
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Follain G, Mercier L, Osmani N, Harlepp S, Goetz JG. Seeing is believing: multi-scale spatio-temporal imaging towards in vivo cell biology. J Cell Sci 2016; 130:23-38. [DOI: 10.1242/jcs.189001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
Life is driven by a set of biological events that are naturally dynamic and tightly orchestrated from the single molecule to entire organisms. Although biochemistry and molecular biology have been essential in deciphering signaling at a cellular and organismal level, biological imaging has been instrumental for unraveling life processes across multiple scales. Imaging methods have considerably improved over the past decades and now allow to grasp the inner workings of proteins, organelles, cells, organs and whole organisms. Not only do they allow us to visualize these events in their most-relevant context but also to accurately quantify underlying biomechanical features and, so, provide essential information for their understanding. In this Commentary, we review a palette of imaging (and biophysical) methods that are available to the scientific community for elucidating a wide array of biological events. We cover the most-recent developments in intravital imaging, light-sheet microscopy, super-resolution imaging, and correlative light and electron microscopy. In addition, we illustrate how these technologies have led to important insights in cell biology, from the molecular to the whole-organism resolution. Altogether, this review offers a snapshot of the current and state-of-the-art imaging methods that will contribute to the understanding of life and disease.
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Affiliation(s)
- Gautier Follain
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
| | - Luc Mercier
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
| | - Naël Osmani
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
| | - Sébastien Harlepp
- Université de Strasbourg, Strasbourg F-67000, France
- DON: Optique ultrarapide et nanophotonique, IPCMS UMR7504, Strasbourg 67000, France
- LabEx NIE, Université de Strasbourg, Strasbourg F-67000, France
| | - Jacky G. Goetz
- Microenvironmental Niche in Tumorigenesis and Targeted Therapy, Inserm U1109, MN3T, Strasbourg F-67200, France
- Université de Strasbourg, Strasbourg F-67000, France
- LabEx Medalis, Université de Strasbourg, Strasbourg, F-67000, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg F-67000, France
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130
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Aekbote BL, Fekete T, Jacak J, Vizsnyiczai G, Ormos P, Kelemen L. Surface-modified complex SU-8 microstructures for indirect optical manipulation of single cells. BIOMEDICAL OPTICS EXPRESS 2016; 7:45-56. [PMID: 26819816 PMCID: PMC4722909 DOI: 10.1364/boe.7.000045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 11/19/2015] [Accepted: 11/20/2015] [Indexed: 05/24/2023]
Abstract
We introduce a method that combines two-photon polymerization (TPP) and surface functionalization to enable the indirect optical manipulation of live cells. TPP-made 3D microstructures were coated specifically with a multilayer of the protein streptavidin and non-specifically with IgG antibody using polyethylene glycol diamine as a linker molecule. Protein density on their surfaces was quantified for various coating methods. The streptavidin-coated structures were shown to attach to biotinated cells reproducibly. We performed basic indirect optical micromanipulation tasks with attached structure-cell couples using complex structures and a multi-focus optical trap. The use of such extended manipulators for indirect optical trapping ensures to keep a safe distance between the trapping beams and the sensitive cell and enables their 6 degrees of freedom actuation.
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Affiliation(s)
- Badri L. Aekbote
- Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Tamás Fekete
- Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Jaroslaw Jacak
- University of Applied Sciences Upper Austria, Garnisonstraße 21, 4020 Linz, Austria
| | - Gaszton Vizsnyiczai
- Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Pál Ormos
- Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
| | - Lóránd Kelemen
- Biological Research Centre of the Hungarian Academy of Sciences, Temesvári krt. 62, Szeged 6726, Hungary
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131
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Guirao B, Rigaud SU, Bosveld F, Bailles A, López-Gay J, Ishihara S, Sugimura K, Graner F, Bellaïche Y. Unified quantitative characterization of epithelial tissue development. eLife 2015; 4. [PMID: 26653285 PMCID: PMC4811803 DOI: 10.7554/elife.08519] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 11/03/2015] [Indexed: 12/20/2022] Open
Abstract
Understanding the mechanisms regulating development requires a quantitative characterization of cell divisions, rearrangements, cell size and shape changes, and apoptoses. We developed a multiscale formalism that relates the characterizations of each cell process to tissue growth and morphogenesis. Having validated the formalism on computer simulations, we quantified separately all morphogenetic events in the Drosophila dorsal thorax and wing pupal epithelia to obtain comprehensive statistical maps linking cell and tissue scale dynamics. While globally cell shape changes, rearrangements and divisions all significantly participate in tissue morphogenesis, locally, their relative participations display major variations in space and time. By blocking division we analyzed the impact of division on rearrangements, cell shape changes and tissue morphogenesis. Finally, by combining the formalism with mechanical stress measurement, we evidenced unexpected interplays between patterns of tissue elongation, cell division and stress. Our formalism provides a novel and rigorous approach to uncover mechanisms governing tissue development. DOI:http://dx.doi.org/10.7554/eLife.08519.001 In animals, the final size and shape of each tissue is determined by the precise control of when, where and how much individual cells grow, divide, move and die. An important challenge in biology is to understand how the behaviors of each individual cell can act together to generate a large and reproducible change at the scale of entire tissues and organs. Here, Guirao et al. have developed a new approach to provide maps that reveal how much each cell process contributes to the development of tissues. A caterpillar becoming a butterfly is a famous example of insect ‘metamorphosis’. The fruit fly offers another example of such tissue development: within five days, a rice grain-like maggot morphs into an adult fly with long antennae, legs and wings. Guirao et al. used a microscope to observe cells over a period of several hours during the metamorphosis of the adult fruit fly wings and thorax (the region between the neck and abdomen). In both regions, Guirao et al. showed that all the cell processes participate in the formation of the adult tissue. Cell division, cell death, and changes in cell size affect the size of the tissue, while cell division, cell rearrangements, and changes in cell shape alter the shape of the tissue. The relative contributions of these cell processes varied a lot in both space and time. Further experiments then used mutant flies with defects in cell division to analyse the impact of cell division on the other cell processes and the eventual shape of the tissue. Finally, Guirao et al. showed that there are unexpected interactions between the patterns of tissue growth, cell division and the mechanical forces in the tissue. These findings provide a new approach to uncover how animals from different species can have such a variety of shapes and sizes, even though they each start life as a single cell. Ultimately, this may also aid efforts to understand how certain diseases affect the development of tissues. DOI:http://dx.doi.org/10.7554/eLife.08519.002
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Affiliation(s)
- Boris Guirao
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Stéphane U Rigaud
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Floris Bosveld
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Anaïs Bailles
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Jesús López-Gay
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
| | - Shuji Ishihara
- Department of Physics, School of Science and Technology, Meiji University, Kanagawa, Japan
| | - Kaoru Sugimura
- Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency, Tokyo, Japan
| | - François Graner
- Laboratoire Matière et Systèmes Complexes (CNRS UMR7057), Université Paris-Diderot, Paris, France
| | - Yohanns Bellaïche
- Polarity, Division and Morphogenesis Team, Genetics and Developmental Biology Unit (CNRS UMR3215/Inserm U934), Institut Curie, Paris, France
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132
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Turlier H, Maître JL. Mechanics of tissue compaction. Semin Cell Dev Biol 2015; 47-48:110-7. [PMID: 26256955 PMCID: PMC5484403 DOI: 10.1016/j.semcdb.2015.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/30/2015] [Accepted: 08/03/2015] [Indexed: 01/01/2023]
Abstract
During embryonic development, tissues deform by a succession and combination of morphogenetic processes. Tissue compaction is the morphogenetic process by which a tissue adopts a tighter structure. Recent studies characterized the respective roles of cells' adhesive and contractile properties in tissue compaction. In this review, we formalize the mechanical and molecular principles of tissue compaction and we analyze through the prism of this framework several morphogenetic events: the compaction of the early mouse embryo, the formation of the fly retina, the segmentation of somites and the separation of germ layers during gastrulation.
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Affiliation(s)
- Hervé Turlier
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jean-Léon Maître
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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133
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Machado PF, Duque J, Étienne J, Martinez-Arias A, Blanchard GB, Gorfinkiel N. Emergent material properties of developing epithelial tissues. BMC Biol 2015; 13:98. [PMID: 26596771 PMCID: PMC4656187 DOI: 10.1186/s12915-015-0200-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/13/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Force generation and the material properties of cells and tissues are central to morphogenesis but remain difficult to measure in vivo. Insight is often limited to the ratios of mechanical properties obtained through disruptive manipulation, and the appropriate models relating stress and strain are unknown. The Drosophila amnioserosa epithelium progressively contracts over 3 hours of dorsal closure, during which cell apices exhibit area fluctuations driven by medial myosin pulses with periods of 1.5-6 min. Linking these two timescales and understanding how pulsatile contractions drive morphogenetic movements is an urgent challenge. RESULTS We present a novel framework to measure in a continuous manner the mechanical properties of epithelial cells in the natural context of a tissue undergoing morphogenesis. We show that the relationship between apicomedial myosin fluorescence intensity and strain during fluctuations is consistent with a linear behaviour, although with a lag. We thus used myosin fluorescence intensity as a proxy for active force generation and treated cells as natural experiments of mechanical response under cyclic loading, revealing unambiguous mechanical properties from the hysteresis loop relating stress to strain. Amnioserosa cells can be described as a contractile viscoelastic fluid. We show that their emergent mechanical behaviour can be described by a linear viscoelastic rheology at timescales relevant for tissue morphogenesis. For the first time, we establish relative changes in separate effective mechanical properties in vivo. Over the course of dorsal closure, the tissue solidifies and effective stiffness doubles as net contraction of the tissue commences. Combining our findings with those from previous laser ablation experiments, we show that both apicomedial and junctional stress also increase over time, with the relative increase in apicomedial stress approximately twice that of other obtained measures. CONCLUSIONS Our results show that in an epithelial tissue undergoing net contraction, stiffness and stress are coupled. Dorsal closure cell apical contraction is driven by the medial region where the relative increase in stress is greater than that of stiffness. At junctions, by contrast, the relative increase in the mechanical properties is the same, so the junctional contribution to tissue deformation is constant over time. An increase in myosin activity is likely to underlie, at least in part, the change in medioapical properties and we suggest that its greater effect on stress relative to stiffness is fundamental to actomyosin systems and confers on tissues the ability to regulate contraction rates in response to changes in external mechanics.
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Affiliation(s)
- Pedro F Machado
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Julia Duque
- Centro de Biología Molecular Severo Ochoa, CSIC, C/ Nicolás Cabrera 1, Madrid, 28049, Spain
| | - Jocelyn Étienne
- Université Grenoble Alpes, Laboratoire Interdisciplinaire de Physique, BP 53, Cedex 9, Grenoble, 38041, France.,CNRS, Laboratoire Interdisciplinaire de Physique, BP 53, Cedex 9, Grenoble, 38041, France
| | | | - Guy B Blanchard
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK.
| | - Nicole Gorfinkiel
- Centro de Biología Molecular Severo Ochoa, CSIC, C/ Nicolás Cabrera 1, Madrid, 28049, Spain.
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134
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Collinet C, Rauzi M, Lenne PF, Lecuit T. Local and tissue-scale forces drive oriented junction growth during tissue extension. Nat Cell Biol 2015; 17:1247-58. [PMID: 26389664 DOI: 10.1038/ncb3226] [Citation(s) in RCA: 182] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 07/20/2015] [Indexed: 12/16/2022]
Abstract
Convergence-extension is a widespread morphogenetic process driven by polarized cell intercalation. In the Drosophila germ band, epithelial intercalation comprises loss of junctions between anterior-posterior neighbours followed by growth of new junctions between dorsal-ventral neighbours. Much is known about how active stresses drive polarized junction shrinkage. However, it is unclear how tissue convergence-extension emerges from local junction remodelling and what the specific role, if any, of junction growth is. Here we report that tissue convergence and extension correlate mostly with new junction growth. Simulations and in vivo mechanical perturbations reveal that junction growth is due to local polarized stresses driven by medial actomyosin contractions. Moreover, we find that tissue-scale pulling forces at the boundary with the invaginating posterior midgut actively participate in tissue extension by orienting junction growth. Thus, tissue extension is akin to a polarized fluid flow that requires parallel and concerted local and tissue-scale forces to drive junction growth and cell-cell displacement.
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Affiliation(s)
- Claudio Collinet
- Aix Marseille Université, CNRS, IBDM UMR7288 13009 Marseille, France
| | - Matteo Rauzi
- EMBL Heidelberg, Meyerhofstrasse 1 69117 Heidelberg, Germany
| | | | - Thomas Lecuit
- Aix Marseille Université, CNRS, IBDM UMR7288 13009 Marseille, France
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135
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Guan Y, Shan X, Zhang F, Wang S, Chen HY, Tao N. Kinetics of small molecule interactions with membrane proteins in single cells measured with mechanical amplification. SCIENCE ADVANCES 2015; 1:e1500633. [PMID: 26601298 PMCID: PMC4646812 DOI: 10.1126/sciadv.1500633] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/14/2015] [Indexed: 05/21/2023]
Abstract
Measuring small molecule interactions with membrane proteins in single cells is critical for understanding many cellular processes and for screening drugs. However, developing such a capability has been a difficult challenge. We show that molecular interactions with membrane proteins induce a mechanical deformation in the cellular membrane, and real-time monitoring of the deformation with subnanometer resolution allows quantitative analysis of small molecule-membrane protein interaction kinetics in single cells. This new strategy provides mechanical amplification of small binding signals, making it possible to detect small molecule interactions with membrane proteins. This capability, together with spatial resolution, also allows the study of the heterogeneous nature of cells by analyzing the interaction kinetics variability between different cells and between different regions of a single cell.
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Affiliation(s)
- Yan Guan
- Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Electrical Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA
| | - Xiaonan Shan
- Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Fenni Zhang
- Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Electrical Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA
| | - Shaopeng Wang
- Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
- Corresponding author. E-mail: (N.T.); (H.-Y.C.)
| | - Nongjian Tao
- Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
- School of Electrical Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
- Corresponding author. E-mail: (N.T.); (H.-Y.C.)
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136
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Lan H, Wang Q, Fernandez-Gonzalez R, Feng JJ. A biomechanical model for cell polarization and intercalation duringDrosophilagermband extension. Phys Biol 2015; 12:056011. [DOI: 10.1088/1478-3975/12/5/056011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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137
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Yang Z, Piksarv P, Ferrier DE, Gunn-Moore FJ, Dholakia K. Macro-optical trapping for sample confinement in light sheet microscopy. BIOMEDICAL OPTICS EXPRESS 2015; 6:2778-85. [PMID: 26309743 PMCID: PMC4541507 DOI: 10.1364/boe.6.002778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/18/2015] [Accepted: 06/29/2015] [Indexed: 05/18/2023]
Abstract
Light sheet microscopy is a powerful approach to construct three-dimensional images of large specimens with minimal photo-damage and photo-bleaching. To date, the specimens are usually mounted in agents such as agarose, potentially restricting the development of live samples, and also highly mobile specimens need to be anaesthetized before imaging. To overcome these problems, here we demonstrate an integrated light sheet microscope which solely uses optical forces to trap and hold the sample using a counter-propagating laser beam geometry. Specifically, tobacco plant cells and living Spirobranchus lamarcki larvae were successfully trapped and sectional images acquired. This novel approach has the potential to significantly expand the range of applications for light sheet imaging.
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Affiliation(s)
- Zhengyi Yang
- SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS,
UK
| | - Peeter Piksarv
- SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS,
UK
- Institute of Physics, University of Tartu, Ravila 14c, Tartu, 50411,
Estonia
| | - David E.K. Ferrier
- The Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St. Andrews, East Sands, St. Andrews, KY16 8LB,
UK
| | - Frank J. Gunn-Moore
- School of Biology, Medical and Biological Sciences Building, University of St. Andrews, North Haugh, St. Andrews, KY16 9TF,
UK
| | - Kishan Dholakia
- SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS,
UK
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138
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Abstract
Advances in cell and developmental biology have often been closely linked to advances in our ability to visualize structure and function at many length and time scales. In this review, we discuss how new imaging technologies and new reagents have provided novel insights into the biology of cadherin-based cell-cell junctions. We focus on three developments: the application of super-resolution optical technologies to characterize the nanoscale organization of cadherins at cell-cell contacts, new approaches to interrogate the mechanical forces that act upon junctions, and advances in electron microscopy which have the potential to transform our understanding of cell-cell junctions.
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Affiliation(s)
- Alpha S Yap
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland, 4072, Australia
| | - Magdalene Michael
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland, 4072, Australia
| | - Robert G Parton
- Division of Cell Biology and Molecular Medicine, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Brisbane, Queensland, 4072, Australia
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139
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E-cadherin junctions as active mechanical integrators in tissue dynamics. Nat Cell Biol 2015; 17:533-9. [PMID: 25925582 DOI: 10.1038/ncb3136] [Citation(s) in RCA: 369] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
During epithelial morphogenesis, E-cadherin adhesive junctions play an important part in mechanically coupling the contractile cortices of cells together, thereby distributing the stresses that drive cell rearrangements at both local and tissue levels. Here we discuss the concept that cellular contractility and E-cadherin-based adhesion are functionally integrated by biomechanical feedback pathways that operate on molecular, cellular and tissue scales.
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140
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Etournay R, Popović M, Merkel M, Nandi A, Blasse C, Aigouy B, Brandl H, Myers G, Salbreux G, Jülicher F, Eaton S. Interplay of cell dynamics and epithelial tension during morphogenesis of the Drosophila pupal wing. eLife 2015; 4:e07090. [PMID: 26102528 PMCID: PMC4574473 DOI: 10.7554/elife.07090] [Citation(s) in RCA: 208] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/18/2015] [Indexed: 11/21/2022] Open
Abstract
How tissue shape emerges from the collective mechanical properties and behavior of individual cells is not understood. We combine experiment and theory to study this problem in the developing wing epithelium of Drosophila. At pupal stages, the wing-hinge contraction contributes to anisotropic tissue flows that reshape the wing blade. Here, we quantitatively account for this wing-blade shape change on the basis of cell divisions, cell rearrangements and cell shape changes. We show that cells both generate and respond to epithelial stresses during this process, and that the nature of this interplay specifies the pattern of junctional network remodeling that changes wing shape. We show that patterned constraints exerted on the tissue by the extracellular matrix are key to force the tissue into the right shape. We present a continuum mechanical model that quantitatively describes the relationship between epithelial stresses and cell dynamics, and how their interplay reshapes the wing.
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Affiliation(s)
- Raphaël Etournay
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Marko Popović
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Matthias Merkel
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Amitabha Nandi
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Corinna Blasse
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Benoît Aigouy
- Institut de Biologie du Développement de Marseille, Marseille, France
| | - Holger Brandl
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Gene Myers
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Guillaume Salbreux
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Lincoln's Inn Fields Laboratories, The Francis Crick Institute, London, United Kingdom
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Suzanne Eaton
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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141
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Ladoux B, Nelson WJ, Yan J, Mège RM. The mechanotransduction machinery at work at adherens junctions. Integr Biol (Camb) 2015; 7:1109-19. [PMID: 25968913 DOI: 10.1039/c5ib00070j] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The shaping of a multicellular body, and the maintenance and repair of adult tissues require fine-tuning of cell adhesion responses and the transmission of mechanical load between the cell, its neighbors and the underlying extracellular matrix. A growing field of research is focused on how single cells sense mechanical properties of their micro-environment (extracellular matrix, other cells), and on how mechanotransduction pathways affect cell shape, migration, survival as well as differentiation. Within multicellular assemblies, the mechanical load imposed by the physical properties of the environment is transmitted to neighboring cells. Force imbalance at cell-cell contacts induces essential morphogenetic processes such as cell-cell junction remodeling, cell polarization and migration, cell extrusion and cell intercalation. However, how cells respond and adapt to the mechanical properties of neighboring cells, transmit forces, and transform mechanical signals into chemical signals remain open questions. A defining feature of compact tissues is adhesion between cells at the specialized adherens junction (AJ) involving the cadherin super-family of Ca(2+)-dependent cell-cell adhesion proteins (e.g., E-cadherin in epithelia). Cadherins bind to the cytoplasmic protein β-catenin, which in turn binds to the filamentous (F)-actin binding adaptor protein α-catenin, which can also recruit vinculin, making the mechanical connection between cell-cell adhesion proteins and the contractile actomyosin cytoskeleton. The cadherin-catenin adhesion complex is a key component of the AJ, and contributes to cell assembly stability and dynamic cell movements. It has also emerged as the main route of propagation of forces within epithelial and non-epithelial tissues. Here, we discuss recent molecular studies that point toward force-dependent conformational changes in α-catenin that regulate protein interactions in the cadherin-catenin adhesion complex, and show that α-catenin is the core mechanosensor that allows cells to locally sense, transduce and adapt to environmental mechanical constrains.
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Affiliation(s)
- B Ladoux
- Institut Jacques Monod, CNRS, Université Paris Diderot, Paris, France.
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