151
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Chen T, Callan-Jones A, Fedorov E, Ravasio A, Brugués A, Ong HT, Toyama Y, Low BC, Trepat X, Shemesh T, Voituriez R, Ladoux B. Large-scale curvature sensing by directional actin flow drives cellular migration mode switching. NATURE PHYSICS 2019; 15:393-402. [PMID: 30984281 PMCID: PMC6456019 DOI: 10.1038/s41567-018-0383-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 11/14/2018] [Indexed: 05/21/2023]
Abstract
Cell migration over heterogeneous substrates during wound healing or morphogenetic processes leads to shape changes driven by different organizations of the actin cytoskeleton and by functional changes including lamellipodial protrusions and contractile actin cables. Cells distinguish between cell-sized positive and negative curvatures in their physical environment by forming protrusions at positive ones and actin cables at negative ones; however, the cellular mechanisms remain unclear. Here, we report that concave edges promote polarized actin structures with actin flow directed towards the cell edge, in contrast to well-documented retrograde flow at convex edges. Anterograde flow and contractility induce a tension anisotropy gradient. A polarized actin network is formed, accompanied by a local polymerization-depolymerization gradient, together with leading-edge contractile actin cables in the front. These cables extend onto non-adherent regions while still maintaining contact with the substrate through focal adhesions. The contraction and dynamic reorganization of this actin structure allows forward movements enabling cell migration over non-adherent regions on the substrate. These versatile functional structures may help cells sense and navigate their environment by adapting to external geometric and mechanical cues.
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Affiliation(s)
- Tianchi Chen
- Mechanobiology Institute, National University of Singapore, Singapore
| | - Andrew Callan-Jones
- Laboratoire Matière et Systèmes Complexes, UMR 7057, CNRS and Université Paris Diderot, Paris, France
| | | | - Andrea Ravasio
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Agustí Brugués
- Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Hui Ting Ong
- Mechanobiology Institute, National University of Singapore, Singapore
| | - Yusuke Toyama
- Mechanobiology Institute, National University of Singapore, Singapore
- Department of Biological Sciences, National University of Singapore
- Temasek Life Sciences Laboratory, Singapore
| | - Boon Chuan Low
- Mechanobiology Institute, National University of Singapore, Singapore
- Department of Biological Sciences, National University of Singapore
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), and Universitat de Barcelona, Barcelona, Spain
| | - Tom Shemesh
- Technion – Israel Institute of Technology, Israel
| | - Raphaël Voituriez
- Laboratoire Jean Perrin and Laboratoire de Physique Theorique de la Matiere Condensee, CNRS/Sorbonne Université, Paris, France
- Corresponding authors: Benoît Ladoux; ; Raphaël Voituriez;
| | - Benoît Ladoux
- Mechanobiology Institute, National University of Singapore, Singapore
- Institut Jacques Monod (IJM), CNRS UMR 7592 & Université Paris Diderot, Paris, France
- Corresponding authors: Benoît Ladoux; ; Raphaël Voituriez;
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152
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Regulation of Actin Dynamics in the C. elegans Somatic Gonad. J Dev Biol 2019; 7:jdb7010006. [PMID: 30897735 PMCID: PMC6473838 DOI: 10.3390/jdb7010006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/13/2019] [Accepted: 03/15/2019] [Indexed: 11/25/2022] Open
Abstract
The reproductive system of the hermaphroditic nematode C. elegans consists of a series of contractile cell types—including the gonadal sheath cells, the spermathecal cells and the spermatheca–uterine valve—that contract in a coordinated manner to regulate oocyte entry and exit of the fertilized embryo into the uterus. Contraction is driven by acto-myosin contraction and relies on the development and maintenance of specialized acto-myosin networks in each cell type. Study of this system has revealed insights into the regulation of acto-myosin network assembly and contractility in vivo.
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153
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Xiao Y, Riahi R, Torab P, Zhang DD, Wong PK. Collective Cell Migration in 3D Epithelial Wound Healing. ACS NANO 2019; 13:1204-1212. [PMID: 30758172 DOI: 10.1021/acsnano.8b06305] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Collective cell migration plays a pivotal role in development, wound healing, and metastasis, but little is known about the mechanisms and coordination of cell migration in 3D microenvironments. Here, we demonstrate a 3D wound healing assay by photothermal ablation for investigating collective cell migration in epithelial tissue structures. The nanoparticle-mediated photothermal technique creates local hyperthermia for selective cell ablation and induces collective cell migration of 3D tissue structures. By incorporating dynamic single cell gene expression analysis, live cell actin staining, and particle image velocimetry, we show that the wound healing response consists of 3D vortex motion moving toward the wound followed by the formation of multicellular actin bundles and leader cells with active actin-based protrusions. Inhibition of ROCK signaling disrupts the multicellular actin bundle and enhances the formation of leader cells at the leading edge. Furthermore, single cell gene expression analysis, pharmacological perturbation, and RNA interference reveal that Notch1-Dll4 signaling negatively regulates the formation of multicellular actin bundles and leader cells. Taken together, our study demonstrates a platform for investigating 3D collective cell migration and underscores the essential roles of ROCK and Notch1-Dll4 signaling in regulating 3D epithelial wound healing.
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Affiliation(s)
| | - Reza Riahi
- Harvard-MIT Division of Health Sciences and Technology , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | | | | | - Pak Kin Wong
- Department of Surgery , The Pennsylvania State University , Hershey , Pennsylvania 17033 , United States
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154
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Fujii Y, Ochi Y, Tuchiya M, Kajita M, Fujita Y, Ishimoto Y, Okajima T. Spontaneous Spatial Correlation of Elastic Modulus in Jammed Epithelial Monolayers Observed by AFM. Biophys J 2019; 116:1152-1158. [PMID: 30826009 DOI: 10.1016/j.bpj.2019.01.037] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 01/19/2019] [Accepted: 01/28/2019] [Indexed: 12/28/2022] Open
Abstract
For isolated single cells on a substrate, the intracellular stiffness, which is often measured as the Young's modulus, E, by atomic force microscopy (AFM), depends on the substrate rigidity. However, little is known about how the E of cells is influenced by the surrounding cells in a cell population system in which cells physically and tightly contact adjacent cells. In this study, we investigated the spatial heterogeneities of E in a jammed epithelial monolayer in which cell migration was highly inhibited, allowing us to precisely measure the spatial distribution of E in large-scale regions by AFM. The AFM measurements showed that E can be characterized using two spatial correlation lengths: the shorter correlation length, lS, is within the single cell size, whereas the longer correlation length, lL, is longer than the distance between adjacent cells and corresponds to the intercellular correlation of E. We found that lL decreased significantly when the actin filaments were disrupted or calcium ions were chelated using chemical treatments, and the decreased lL recovered to the value in the control condition after the treatments were washed out. Moreover, we found that lL decreased significantly when E-cadherin was knocked down. These results indicate that the observed long-range correlation of E is not fixed within the jammed state but inherently arises from the formation of a large-scale actin filament structure via E-cadherin-dependent cell-cell junctions.
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Affiliation(s)
- Yuki Fujii
- Graduate School of Information Science and Technology, Sapporo, Japan
| | - Yuki Ochi
- Graduate School of Information Science and Technology, Sapporo, Japan
| | - Masahiro Tuchiya
- Graduate School of Information Science and Technology, Sapporo, Japan
| | - Mihoko Kajita
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuyuki Fujita
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Yukitaka Ishimoto
- Department of Machine Intelligence and Systems Engineering, Akita Prefectural University, Yurihonjo City, Japan
| | - Takaharu Okajima
- Graduate School of Information Science and Technology, Sapporo, Japan.
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155
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Mueller R, Yeomans JM, Doostmohammadi A. Emergence of Active Nematic Behavior in Monolayers of Isotropic Cells. PHYSICAL REVIEW LETTERS 2019; 122:048004. [PMID: 30768306 DOI: 10.1103/physrevlett.122.048004] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Indexed: 06/09/2023]
Abstract
There is now growing evidence of the emergence and biological functionality of liquid crystal features, including nematic order and topological defects, in cellular tissues. However, how such features that intrinsically rely on particle elongation emerge in monolayers of cells with isotropic shapes is an outstanding question. In this Letter, we present a minimal model of cellular monolayers based on cell deformation and force transmission at the cell-cell interface that explains the formation of topological defects and captures the flow-field and stress patterns around them. By including mechanical properties at the individual cell level, we further show that the instability that drives the formation of topological defects, and leads to active turbulence, emerges from a feedback between shape deformation and active driving. The model allows us to suggest new explanations for experimental observations in tissue mechanics, and to propose designs for future experiments.
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Affiliation(s)
- Romain Mueller
- The Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Parks Road, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Julia M Yeomans
- The Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Parks Road, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Amin Doostmohammadi
- The Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Parks Road, University of Oxford, Oxford OX1 3PU, United Kingdom
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156
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Onochie OE, Zollinger A, Rich CB, Smith M, Trinkaus-Randall V. Epithelial cells exert differential traction stress in response to substrate stiffness. Exp Eye Res 2019; 181:25-37. [PMID: 30653966 DOI: 10.1016/j.exer.2019.01.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/10/2019] [Accepted: 01/13/2019] [Indexed: 10/27/2022]
Abstract
Epithelial wound healing is essential for maintaining the function and clarity of the cornea. Successful repair after injury involves the coordinated movements of cell sheets over the wounded region. While collective migration has been the focus of studies, the effects that environmental changes have on this form of movement are poorly understood. To examine the role of substrate compliancy on multi-layered epithelial sheet migration, we performed traction force and confocal microscopy to determine differences in traction forces and to examine focal adhesions on synthetic and biological substrates. The leading edges of corneal epithelial sheets undergo retraction or contraction prior to migration, and alterations in the sheet's stiffness are affected by the amount of force exerted by cells at the leading edge. On substrates of 30 kPa, cells exhibited greater and more rapid movement than on substrates of 8 kPa, which are similar to that of the corneal basement membrane. Vinculin and its phosphorylated residue Y1065 were prominent along the basal surface of migrating cells, while Y822 was prominent between neighboring cells along the leading edge. Vinculin localization was diffuse on a substrate where the basement membrane was removed. Furthermore, when cells were cultured on fibronectin-coated acrylamide substrates of 8 and 50 kPa and then wounded, there was an injury-induced phosphorylation of Y1065 and substrate dependent changes in the number and size of vinculin containing focal adhesions. These results demonstrate that changes in substrate stiffness affected traction forces and vinculin dynamics, which potentially could contribute to the delayed healing response associated with certain corneal pathologies.
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Affiliation(s)
- Obianamma E Onochie
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA.
| | - Alicia Zollinger
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
| | - Celeste B Rich
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA.
| | - Michael Smith
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
| | - Vickery Trinkaus-Randall
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA; Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USA.
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157
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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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158
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Computational Modeling of Collective Cell Migration: Mechanical and Biochemical Aspects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1146:1-11. [PMID: 31612450 DOI: 10.1007/978-3-030-17593-1_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Collective cell migration plays key roles in various physiological and pathological processes in multicellular organisms, including embryonic development, wound healing, and formation of cancer metastases. Such collective migration involves complex crosstalk among cells and their environment at both biochemical and mechanical levels. Here, we review various computational modeling strategies that have been helpful in decoding the dynamics of collective cell migration. Most of such attempts have focused either aspect - mechanical or biochemical regulation of collective cell migration, and have yielded complementary insights. Finally, we suggest some possible ways to integrate these models to gain a more comprehensive understanding of collective cell migration.
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159
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Ajeti V, Tabatabai AP, Fleszar AJ, Staddon MF, Seara DS, Suarez C, Yousafzai MS, Bi D, Kovar DR, Banerjee S, Murrell MP. Wound Healing Coordinates Actin Architectures to Regulate Mechanical Work. NATURE PHYSICS 2019; 15:696-705. [PMID: 31897085 PMCID: PMC6939997 DOI: 10.1038/s41567-019-0485-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 02/26/2019] [Indexed: 05/20/2023]
Abstract
How cells with diverse morphologies and cytoskeletal architectures modulate their mechanical behaviors to drive robust collective motion within tissues is poorly understood. During wound repair within epithelial monolayers in vitro, cells coordinate the assembly of branched and bundled actin networks to regulate the total mechanical work produced by collective cell motion. Using traction force microscopy, we show that the balance of actin network architectures optimizes the wound closure rate and the magnitude of the mechanical work. These values are constrained by the effective power exerted by the monolayer, which is conserved and independent of actin architectures. Using a cell-based physical model, we show that the rate at which mechanical work is done by the monolayer is limited by the transformation between actin network architectures and differential regulation of cell-substrate friction. These results and our proposed mechanisms provide a robust physical model for how cells collectively coordinate their non-equilibrium behaviors to dynamically regulate tissue-scale mechanical output.
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Affiliation(s)
- Visar Ajeti
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - A Pasha Tabatabai
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - Andrew J Fleszar
- Department of Biomedical Engineering, University of Wisconsin-Madison, 1550 Engineering Drive, Madison, WI, 53706, USA
| | - Michael F Staddon
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK
| | - Daniel S Seara
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - Cristian Suarez
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 E. 58 St, Chicago, IL, 60637, USA
| | - M Sulaiman Yousafzai
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
| | - Dapeng Bi
- Department of Physics, Northeastern University, 111 Dana Research Center, Boston, MA 02115, USA
| | - David R Kovar
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 E. 58 St, Chicago, IL, 60637, USA
| | - Shiladitya Banerjee
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, Gower Street, London WC1E 6BT, UK
| | - Michael P Murrell
- Department of Physics, Yale University, 217 Prospect Street, New Haven, Connecticut 06511, USA
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, USA
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160
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Septiadi D, Abdussalam W, Rodriguez-Lorenzo L, Spuch-Calvar M, Bourquin J, Petri-Fink A, Rothen-Rutishauser B. Revealing the Role of Epithelial Mechanics and Macrophage Clearance during Pulmonary Epithelial Injury Recovery in the Presence of Carbon Nanotubes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1806181. [PMID: 30370701 DOI: 10.1002/adma.201806181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/03/2018] [Indexed: 06/08/2023]
Abstract
Wound healing assays are extensively used to study tissue repair mechanisms; they are typically performed by means of physical (i.e., mechanical, electrical, or optical) detachment of the cells in order to create an open space in which live cells can lodge. Herein, an advanced system based on extensive photobleaching-induced apoptosis; providing a powerful tool to understand the repair response of lung epithelial tissue, consisting of a small injury area where apoptotic cells are still intact, is developed. Notably, the importance of epithelial mechanics and the presence of macrophages during the repair can be understood. The findings reveal that individual epithelial cells are able to clear the apoptotic cells by applying a pushing force, whilst macrophages actively phagocytose the dead cells to create an empty space. It is further shown that this repair mechanism is hampered when carbon nanotubes (CNTs) are introduced: formation of aberrant (i.e., thickening) F-actins, maturation of focal adhesion, and increase in traction force leading to retardation in cell migration are observed. The results provide a mechanistic view of how CNTs can interfere with lung repair.
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Affiliation(s)
- Dedy Septiadi
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Wildan Abdussalam
- Department of High Energy Density, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Laura Rodriguez-Lorenzo
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Miguel Spuch-Calvar
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Joël Bourquin
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
| | - Alke Petri-Fink
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4, 1700, Fribourg, Switzerland
- Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700, Fribourg, Switzerland
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161
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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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162
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Bredov D, Volodyaev I. Increasing complexity: Mechanical guidance and feedback loops as a basis for self-organization in morphogenesis. Biosystems 2018; 173:133-156. [PMID: 30292533 DOI: 10.1016/j.biosystems.2018.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 10/28/2022]
Abstract
The article is devoted to physical views on embryo development as a combination of structurally stable dynamics and symmetry-breaking events in the general process of self-organization. The first corresponds to the deterministic aspect of embryo development. The second type of processes is associated with sudden increase of variability in the periods of symmetry-breaking, which manifests unstable dynamics. The biological basis under these considerations includes chemokinetics (a system of inductors, repressors, and interaction with their next surrounding) and morphomechanics (i.e. mechanotransduction, mechanosensing, and related feedback loops). Although the latter research area is evolving rapidly, up to this time the role of mechanical properties of embryonic tissues and mechano-dependent processes in them are integrated in the general picture of embryo development to a lesser extent than biochemical signaling. For this reason, the present article is mostly devoted to experimental data on morphomechanics in the process of embryo development, also including analysis of its limitations and possible contradictions. The general system of feedback-loops and system dynamics delineated in this review is in large part a repetition of the views of Lev Beloussov, who was one of the founders of the whole areas of morphomechanics and morphodynamics, and to whose memory this article is dedicated.
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Affiliation(s)
- Denis Bredov
- Laboratory of Developmental biophysics, Department of Embryology, Faculty of Biology, Moscow State University, Moscow, 119234, Russia
| | - Ilya Volodyaev
- Laboratory of Developmental biophysics, Department of Embryology, Faculty of Biology, Moscow State University, Moscow, 119234, Russia.
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163
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Labernadie A, Trepat X. Sticking, steering, squeezing and shearing: cell movements driven by heterotypic mechanical forces. Curr Opin Cell Biol 2018; 54:57-65. [DOI: 10.1016/j.ceb.2018.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/05/2018] [Accepted: 04/12/2018] [Indexed: 12/11/2022]
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164
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Staddon MF, Bi D, Tabatabai AP, Ajeti V, Murrell MP, Banerjee S. Cooperation of dual modes of cell motility promotes epithelial stress relaxation to accelerate wound healing. PLoS Comput Biol 2018; 14:e1006502. [PMID: 30273354 PMCID: PMC6181425 DOI: 10.1371/journal.pcbi.1006502] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 10/11/2018] [Accepted: 09/11/2018] [Indexed: 11/19/2022] Open
Abstract
Collective cell migration in cohesive units is vital for tissue morphogenesis, wound repair, and immune response. While the fundamental driving forces for collective cell motion stem from contractile and protrusive activities of individual cells, it remains unknown how their balance is optimized to maintain tissue cohesiveness and the fluidity for motion. Here we present a cell-based computational model for collective cell migration during wound healing that incorporates mechanochemical coupling of cell motion and adhesion kinetics with stochastic transformation of active motility forces. We show that a balance of protrusive motility and actomyosin contractility is optimized for accelerating the rate of wound repair, which is robust to variations in cell and substrate mechanical properties. This balance underlies rapid collective cell motion during wound healing, resulting from a tradeoff between tension mediated collective cell guidance and active stress relaxation in the tissue.
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Affiliation(s)
- Michael F. Staddon
- Department of Physics and Astronomy, University College London, London, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Dapeng Bi
- Department of Physics, Northeastern University, Boston, Massachusetts, United States of America
| | - A. Pasha Tabatabai
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
- Systems Biology Institute, Yale University, West Haven, Connecticut, United States of America
| | - Visar Ajeti
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
- Systems Biology Institute, Yale University, West Haven, Connecticut, United States of America
| | - Michael P. Murrell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
- Systems Biology Institute, Yale University, West Haven, Connecticut, United States of America
- Department of Physics, Yale University, New Haven, Connecticut, United States of America
| | - Shiladitya Banerjee
- Department of Physics and Astronomy, University College London, London, United Kingdom
- Institute for the Physics of Living Systems, University College London, London, United Kingdom
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165
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Schaumann EN, Staddon MF, Gardel ML, Banerjee S. Force localization modes in dynamic epithelial colonies. Mol Biol Cell 2018; 29:2835-2847. [PMID: 30207837 PMCID: PMC6249864 DOI: 10.1091/mbc.e18-05-0336] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Collective cell behaviors, including tissue remodeling, morphogenesis, and cancer metastasis, rely on dynamics among cells, their neighbors, and the extracellular matrix. The lack of quantitative models precludes understanding of how cell-cell and cell-matrix interactions regulate tissue-scale force transmission to guide morphogenic processes. We integrate biophysical measurements on model epithelial tissues and computational modeling to explore how cell-level dynamics alter mechanical stress organization at multicellular scales. We show that traction stress distribution in epithelial colonies can vary widely for identical geometries. For colonies with peripheral localization of traction stresses, we recapitulate previously described mechanical behavior of cohesive tissues with a continuum model. By contrast, highly motile cells within colonies produce traction stresses that fluctuate in space and time. To predict the traction force dynamics, we introduce an active adherent vertex model (AAVM) for epithelial monolayers. AAVM predicts that increased cellular motility and reduced intercellular mechanical coupling localize traction stresses in the colony interior, in agreement with our experimental data. Furthermore, the model captures a wide spectrum of localized stress production modes that arise from individual cell activities including cell division, rotation, and polarized migration. This approach provides a robust quantitative framework to study how cell-scale dynamics influence force transmission in epithelial tissues.
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Affiliation(s)
- Erik N Schaumann
- Department of Chemistry, University of Chicago, Chicago, IL 60637
| | - Michael F Staddon
- Department of Physics & Astronomy, University College London, London WC1E 6BT, United Kingdom.,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
| | - Margaret L Gardel
- Department of Physics, University of Chicago, Chicago, IL 60637.,James Franck Institute, University of Chicago, Chicago, IL 60637.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
| | - Shiladitya Banerjee
- Department of Physics & Astronomy, University College London, London WC1E 6BT, United Kingdom.,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
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166
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Sephien A, Peters K, Shoji C, Schwartz-Fernandes FA. Intraoperative Tips for Hand Surgery: A Focus on Reducing Postoperative Scarring and Tendon Rupture. Cureus 2018; 10:e3274. [PMID: 30443445 PMCID: PMC6235636 DOI: 10.7759/cureus.3274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This article is a collection of intraoperative techniques performed by a single hand surgeon with literature support for these techniques for the purpose of circumventing potential limitations intraoperatively. These techniques include the use of a Beaver Blade handle (Beaver, Beaver-Visitec, Waltham, MA, US) to be used as a rasp to smooth intraosseous tunnels during tendon transfers, a Stryker (Stryker, Stryker Corporation, Kalamazoo, MI, US) or Synthes (Deputy Synthes, Johnson & Johnson, West Palm Beach, FL, US) drill as a motorized file for plate deburring, and Insorb forceps (Insorb, Incisive Surgical, Plymouth, MN, US) for skin closure. These tips serve as methods to minimize scarring and circumvent unfortunate obstacles, such as tendon rupture, and the consequential weakened repair that can occur post-operatively. These have not been previously reported in the literature but have been performed by the senior author with no resulting complications. Additionally, the common availability of the equipment allows for a potential economic benefit.
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Affiliation(s)
- Andrew Sephien
- Orthopaedics and Sports Medicine, University of South Florida Morsani College of Medicine, Tampa, USA
| | - Katherine Peters
- Orthopaedics and Sports Medicine, University of South Florida Morsani College of Medicine, Tampa, USA
| | - Christopher Shoji
- Orthopaedics and Sports Medicine, University of South Florida Morsani College of Medicine, Tampa, USA
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167
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Weng W, He S, Song H, Li X, Cao L, Hu Y, Cui J, Zhou Q, Peng H, Su J. Aligned Carbon Nanotubes Reduce Hypertrophic Scar via Regulating Cell Behavior. ACS NANO 2018; 12:7601-7612. [PMID: 30040897 DOI: 10.1021/acsnano.7b07439] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Hypertrophic scars, characterized by excessive cell proliferation, disordered cell growth, and aberrant deposition of collagens, could cause significant clinical problems. Herein, aligned carbon nanotubes (ACNTs) were synthesized via chemical vapor deposition, and bulk ACNTs were pulled out from the arrays. The capacity of the ACNTs to reduce hypertrophic scar formation was evaluated both in vitro and in vivo. The results demonstrated that the ACNTs suppressed the overproliferation of fibroblast cells, directed their growth, and inhibited collagen expression in vitro without cell cytotoxicity. Moreover, in vivo evaluation in a rabbit ear model indicated relieved scar hypertrophy after the ACNTs treatment. The gene expression microarray was further used to understand the mechanism, which showed that ACNTs could inhibit the TGFβ pathway to alter the components in the extracellular matrix, cell proliferation, cell cytoskeleton, and cell motility. These findings may provide a potent strategy of using carbon nanotubes in the bioengineering field.
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Affiliation(s)
| | - Sisi He
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science and Laboratory of Advanced Materials , Fudan University , Shanghai 200438 , China
| | | | | | | | - Yajie Hu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science and Laboratory of Advanced Materials , Fudan University , Shanghai 200438 , China
| | | | | | - Huisheng Peng
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science and Laboratory of Advanced Materials , Fudan University , Shanghai 200438 , China
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168
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Vishwakarma M, Di Russo J, Probst D, Schwarz US, Das T, Spatz JP. Mechanical interactions among followers determine the emergence of leaders in migrating epithelial cell collectives. Nat Commun 2018; 9:3469. [PMID: 30150695 PMCID: PMC6110746 DOI: 10.1038/s41467-018-05927-6] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/23/2018] [Indexed: 01/14/2023] Open
Abstract
Regulating the emergence of leaders is a central aspect of collective cell migration, but the underlying mechanisms remain ambiguous. Here we show that the selective emergence of leader cells at the epithelial wound-margin depends on the dynamics of the follower cells and is spatially limited by the length-scale of collective force transduction. Owing to the dynamic heterogeneity of the monolayer, cells behind the prospective leaders manifest locally increased traction and monolayer stresses much before these leaders display any phenotypic traits. Followers, in turn, pull on the future leaders to elect them to their fate. Once formed, the territory of a leader can extend only to the length up-to which forces are correlated, which is similar to the length up-to which leader cells can transmit forces. These findings provide mechanobiological insight into the hierarchy in cell collectives during epithelial wound healing. During collective cell migration, how leader cells emerge is poorly understood. Here, the authors find that small groups of mechanically-interacting follower cells pull on the future leaders to stochastically elect them to their fate.
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Affiliation(s)
- Medhavi Vishwakarma
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany.,Department of Biophysical Chemistry, Heidelberg University, INF 253, 69120, Heidelberg, Germany
| | - Jacopo Di Russo
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany.,Department of Biophysical Chemistry, Heidelberg University, INF 253, 69120, Heidelberg, Germany
| | - Dimitri Probst
- Institute for Theoretical Physics and BioQuant, Heidelberg University, INF 267, 69120, Heidelberg, Germany
| | - Ulrich S Schwarz
- Institute for Theoretical Physics and BioQuant, Heidelberg University, INF 267, 69120, Heidelberg, Germany
| | - Tamal Das
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany. .,Department of Biophysical Chemistry, Heidelberg University, INF 253, 69120, Heidelberg, Germany. .,TIFR Centre for Interdisciplinary Sciences (TCIS), Tata Institute of Fundamental Research Hyderabad, 500107, Hyderabad, India.
| | - Joachim P Spatz
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany. .,Department of Biophysical Chemistry, Heidelberg University, INF 253, 69120, Heidelberg, Germany.
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169
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Basu S, Sutradhar S, Paul R. Substrate stiffness and mechanical stress due to intercellular cooperativity guides tissue structure. J Theor Biol 2018; 457:124-136. [PMID: 30144408 DOI: 10.1016/j.jtbi.2018.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 07/30/2018] [Accepted: 08/01/2018] [Indexed: 12/31/2022]
Abstract
A key challenge in cell and tissue morphogenesis is to understand how a crucial balance between cell proliferation and apoptosis maintains an evolving tissue structure. These processes are mutually non-exclusive and require stiffness monitoring of the host substrate. Adhered cells actively mechanosense the tension in the extracellular matrix (ECM). They collectively alter self-organization and generate a host of tissue patterns. Using an in silico elastic fiber-network in two dimensions, we simulate cell-ECM composite structures and characterize features of the emerging tissue patterns during successive cell proliferation and apoptosis. Our data reveals that, in general, cell viability is a function of the cell-induced effective ECM stiffness supported by intercellular cooperativity. Translating this into a remodeling tissue, we find that average cell cycle duration in concert with the locally stressed regions of the ECM promote heterogeneous proliferation and apoptosis inducing finger-like protrusions along the tissue periphery - a feature normally observed during tumorigenesis. Further, we find that recovery of a scratch wound is delayed for cells harbored on a compliant or (and) in a highly collagen depleted ECM.
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Affiliation(s)
- S Basu
- Department of Solid State Physics, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata, West Bengal 700032, India.
| | - S Sutradhar
- Department of Solid State Physics, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata, West Bengal 700032, India; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA.
| | - R Paul
- Department of Solid State Physics, Indian Association for the Cultivation of Science, 2A & 2B Raja S. C. Mullick Road, Kolkata, West Bengal 700032, India.
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170
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Crane MJ, Xu Y, Henry WL, Gillis SP, Albina JE, Jamieson AM. Pulmonary influenza A virus infection leads to suppression of the innate immune response to dermal injury. PLoS Pathog 2018; 14:e1007212. [PMID: 30138446 PMCID: PMC6107272 DOI: 10.1371/journal.ppat.1007212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/12/2018] [Indexed: 12/31/2022] Open
Abstract
The innate immune system is responsible for many important functions in the body including responding to infection, clearing cancerous cells, healing wounds, and removing foreign substances. Although many of these functions happen simultaneously in life, most laboratory studies of the innate immune response focus on one activity. How the innate immune system responds to concurrent insults in different parts of the body is not well understood. This study explores the impact of a lung infection on the cutaneous wound healing process. We used two complimentary models of injury: the excisional tail wound and subcutaneous implantation of polyvinyl alcohol (PVA) sponges. These models allow for assessment of the rate of closure and measurement of cellular and cytokine responses during acute wound healing, respectively. When mice with these healing wounds were infected with influenza A virus (IAV) in the lung there was a delay in wound healing. The viral lung infection suppressed the innate immune response in a healing wound, including cellular infiltrate, chemokines, growth factors, and cytokines. However, there was not a global immune suppression as there was an increase in inflammation systemically in mice with both infection and healing wounds compared to mice with only wounds or IAV infection. In addition, the lung immune response was largely unaffected indicating that responding to a lung infection is prioritized over a healing wound. This study introduces the concept of immune triage, in that when faced with multiple insults the immune system prioritizes responses. This paradigm likely applies to many situations that involve the innate immune system, and understanding how the innate immune system handles multiple insults is essential to understanding how it can efficiently clear pathogens while responding to other inflammatory events. In a natural setting, the innate immune system is frequently faced with multiple insults, against which it must mount overlapping inflammatory responses. We are interested in how the innate immune system deals with multiple, simultaneously occurring inflammatory insults, and if the response to one will take priority. For example, the innate immune system is essential in mediating both the early control of pathogen replication in infected tissue and in the early stages of wound healing. Pulmonary infections occur frequently in injured patient populations; therefore, we set out to determine the impact of a respiratory infection on a healing wound. To examine this, mice with healing dermal wounds were infected with influenza A virus (IAV), a common cause of viral pneumonia. We found that the innate immune response to the lung infection took priority at the expense of the healing wound, in that the initial control of viral replication in the lung was not impacted, while the wound healing response was suppressed. Very little work has been done examining how the immune response can respond to overlapping inflammatory insults. Our work shows that not all immune responses are created equal, and that the cells of the innate immune system are preferentially routed towards fighting a lung infection rather than the healing dermal wound. This apparent prioritization of the innate immune response opens up a new direction of study. It is relevant to many fields where competing insults may alter the disease state.
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Affiliation(s)
- Meredith J. Crane
- Division of Biology and Medicine, Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Yun Xu
- Division of Biology and Medicine, Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - William L. Henry
- Division of Biology and Medicine, Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Sean P. Gillis
- Division of Biology and Medicine, Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, United States of America
| | - Jorge E. Albina
- Department of Surgery, Rhode Island Hospital and the Warren Alpert School of Medicine of Brown University, Providence, Rhode Island, United States of America
| | - Amanda M. Jamieson
- Division of Biology and Medicine, Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
- * E-mail:
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171
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Metzner C, Lange J, Krauss P, Wunderling N, Übelacker J, Martin F, Fabry B. Pressure-driven collective growth mechanism of planar cell colonies. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2018; 51:304004. [PMID: 30906071 PMCID: PMC6426131 DOI: 10.1088/1361-6463/aace4c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The growth of cell colonies is determined by the migration and proliferation of the individual cells. This is often modeled with the Fisher-Kolmogorov (FK) equation, which assumes that cells diffuse independently from each other, but stop to proliferate when their density reaches a critial limit. However, when using measured, cell-line specific parameters, we find that the FK equation drastically underestimates the experimentally observed increase of colony radius with time. Moreover, cells in real colonies migrate radially outward with superdiffusive trajectories, in contrast to the assumption of random diffusion. We demonstrate that both dicrepancies can be resolved by assuming that cells in dense colonies are driven apart by repulsive, pressure-like forces. Using this model of proliferating repelling particles (PRP), we find that colony growth exhibits different dynamical regimes, depending on the ratio between a pressure-related equilibrium cell density and the critial density of proliferation arrest.
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Affiliation(s)
- Claus Metzner
- Biophysics Group, Friedrich-Alexander-University, Erlangen, Germany
| | - Janina Lange
- Soft Condensed Matter Group, Ludwig-Maximilians-University, Germany
| | - Patrick Krauss
- Experimental Otolaryngology, University Hospital Erlangen, Germany
| | | | | | | | - Ben Fabry
- Biophysics Group, Friedrich-Alexander-University, Erlangen, Germany
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172
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Theoretical Analysis of Stress Distribution and Cell Polarization Surrounding a Model Wound. Biophys J 2018; 115:398-410. [PMID: 30021114 DOI: 10.1016/j.bpj.2018.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 06/07/2018] [Accepted: 06/07/2018] [Indexed: 01/14/2023] Open
Abstract
A growing amount of experimental evidence shows that the local elastic field acting on cells governs their spatial organization and polarity in a tissue. Interestingly, experiments on wound healing reveal a universal formation of thick actomyosin bundles around the margins of epithelial gaps. Although the forces involved in this process have been measured, the mechanisms governing cellular alignment and contractile ring formation are still not fully understood. To theoretically investigate this process, we have carried out a self-consistent calculation of the elastic field that is actively generated around a circular gap in a contractile cell monolayer that is adhered to an elastic substrate, taking into account the responsiveness of actomyosin activity to the locally generated stress. We model actomyosin contractility by a radial distribution of point force dipoles that may alter in magnitude and orientation in response to the local elastic stress. In addition, the model takes into account the forces exerted by leader cells on the margins of the cell monolayer. Our model suggests that the presence of a hole in the center of a contractile cell monolayer creates a mechanical tendency for actomyosin forces to polarize tangentially around the hole margin. In addition, it predicts that this tendency optimizes with substrate rigidity, thickness, and strength of cell adhesion to the substrate. Our calculations support the view that the universal formation of a peripheral contractile ring is a consequence of actomyosin contractility in the bulk and its inherent responsiveness to the local stress.
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173
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Galior K, Ma VPY, Liu Y, Su H, Baker N, Panettieri RA, Wongtrakool C, Salaita K. Molecular Tension Probes to Investigate the Mechanopharmacology of Single Cells: A Step toward Personalized Mechanomedicine. Adv Healthc Mater 2018; 7:e1800069. [PMID: 29785773 PMCID: PMC6105437 DOI: 10.1002/adhm.201800069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/15/2018] [Indexed: 01/03/2023]
Abstract
Given that dysregulation of mechanics contributes to diseases ranging from cancer metastasis to lung disease, it is important to develop methods for screening the efficacy of drugs that target cellular forces. Here, nanoparticle-based tension sensors are used to quantify the mechanical response of individual cells upon drug treatment. As a proof-of-concept, the activity of bronchodilators is tested on human airway smooth muscle cells derived from seven donors, four of which are asthmatic. It is revealed that airway smooth muscle cells isolated from asthmatic donors exhibit greater traction forces compared to the control donors. Additionally, the mechanical signal is abolished using myosin inhibitors or further enhanced in the presence of inflammatory inducers, such as nicotine. Using the signal generated by the probes, single-cell dose-response measurements are performed to determine the "mechano" effective concentration (mechano-EC50 ) of albuterol, a bronchodilator, which reduces integrin forces by 50%. Mechano-EC50 values for each donor present discrete readings that are differentially enhanced as a function of nicotine treatment. Importantly, donor mechano-EC50 values varied by orders of magnitude, suggesting significant variability in their sensitivity to nicotine and albuterol treatment. To the best of the authors' knowledge, this is the first study harnessing a piconewton tension sensor platform for mechanopharmacology.
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Affiliation(s)
- Kornelia Galior
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | | | - Yang Liu
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Hanquan Su
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Nusaiba Baker
- Emory University School of Medicine, Emory University, Atlanta, GA, 30307, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Cherry Wongtrakool
- Emory University School of Medicine, Emory University, Atlanta, GA, 30307, USA
- Atlanta Veterans Affairs Medical Center, Decatur, GA, 30033, USA
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Winship Cancer Institute, Emory University, Atlanta, GA, 30322, USA
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174
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Kim EJY, Korotkevich E, Hiiragi T. Coordination of Cell Polarity, Mechanics and Fate in Tissue Self-organization. Trends Cell Biol 2018; 28:541-550. [DOI: 10.1016/j.tcb.2018.02.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 02/06/2023]
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175
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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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176
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Stoecklin C, Yue Z, Chen WW, de Mets R, Fong E, Studer V, Viasnoff V. A New Approach to Design Artificial 3D Microniches with Combined Chemical, Topographical, and Rheological Cues. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201700237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Celine Stoecklin
- Mechanobiology Institute; 5A Engineering Drive 1 Singapore 117411 Singapore
| | - Zhang Yue
- Mechanobiology Institute; 5A Engineering Drive 1 Singapore 117411 Singapore
| | - Wilhelm W. Chen
- Mechanobiology Institute; 5A Engineering Drive 1 Singapore 117411 Singapore
- School of Materials Science and Engineering; Nanyang Technological University; N4.1, 50 Nanyang Avenue Singapore 639798 Singapore
| | - Richard de Mets
- Mechanobiology Institute; 5A Engineering Drive 1 Singapore 117411 Singapore
| | - Eileen Fong
- School of Materials Science and Engineering; Nanyang Technological University; N4.1, 50 Nanyang Avenue Singapore 639798 Singapore
| | - Vincent Studer
- CNRS; Interdisciplinary Institute for Neuroscience; UMR 5297 Bordeaux F-33000 France
| | - Virgile Viasnoff
- Mechanobiology Institute; 5A Engineering Drive 1 Singapore 117411 Singapore
- CNRS; UMI 3639 5A Engineering Drive 1 Singapore 117411 Singapore
- Department of Biological Sciences; National university of Singapore; 14 Science Drive 4 Singapore 117543 Singapore
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177
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Chepizhko O, Lionetti MC, Malinverno C, Giampietro C, Scita G, Zapperi S, La Porta CAM. From jamming to collective cell migration through a boundary induced transition. SOFT MATTER 2018; 14:3774-3782. [PMID: 29713711 DOI: 10.1039/c8sm00128f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Cell monolayers provide an interesting example of active matter, exhibiting a phase transition from flowing to jammed states as they age. Here we report experiments and numerical simulations illustrating how a jammed cellular layer rapidly reverts to a flowing state after a wound. Quantitative comparison between experiments and simulations shows that cells change their self-propulsion and alignment strength so that the system crosses a phase transition line, which we characterize by finite-size scaling in an active particle model. This wound-induced unjamming transition is found to occur generically in epithelial, endothelial and cancer cells.
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Affiliation(s)
- Oleksandr Chepizhko
- Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, Technikerstrasse 21a, A-6020 Innsbruck, Austria
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178
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Sussman DM, Merkel M. No unjamming transition in a Voronoi model of biological tissue. SOFT MATTER 2018; 14:3397-3403. [PMID: 29667689 DOI: 10.1039/c7sm02127e] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Vertex models are a popular approach to simulating the mechanical and dynamical properties of dense biological tissues, describing the tissue as a network of polygons. Recently a class of two-dimensional vertex models was shown to exhibit a disordered rigidity transition controlled by the preferred cellular geometry, which was subsequently echoed by experimental findings. An attractive variant of these models uses a Voronoi tessellation to describe the cells, which reduces the number of degrees of freedom as compared the original vertex model. The Voronoi model was also endowed with a non-equilibrium model of cellular motility, leading to rich, glassy behavior. This glassy behavior was suggested to be inextricably linked to an underlying jamming transition. We test this conjecture, exploring the low-effective-temperature limit of the 2D Voronoi model by studying cell trajectories from detailed dynamical simulations in combination with rigidity measurements of energy-minimized disordered cell configurations. We find that the zero-temperature limit of this model has no unjamming transition. We show that this absence of an unjamming transition is intimately linked to the marginality of the model, i.e. the fact that the constraints imposed on cell areas and perimeters precisely balance the number of degrees of freedom in the model. Our work suggests that constraint counting arguments are useful to understand rigidity in a broad class of models of dense biological tissues.
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Affiliation(s)
- Daniel M Sussman
- Department of Physics, Syracuse University, Physics Building, Syracuse, New York 13210, USA.
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179
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Yang R, Broussard JA, Green KJ, Espinosa HD. Techniques to stimulate and interrogate cell-cell adhesion mechanics. EXTREME MECHANICS LETTERS 2018; 20:125-139. [PMID: 30320194 PMCID: PMC6181239 DOI: 10.1016/j.eml.2017.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cell-cell adhesions maintain the mechanical integrity of multicellular tissues and have recently been found to act as mechanotransducers, translating mechanical cues into biochemical signals. Mechanotransduction studies have primarily focused on focal adhesions, sites of cell-substrate attachment. These studies leverage technical advances in devices and systems interfacing with living cells through cell-extracellular matrix adhesions. As reports of aberrant signal transduction originating from mutations in cell-cell adhesion molecules are being increasingly associated with disease states, growing attention is being paid to this intercellular signaling hub. Along with this renewed focus, new requirements arise for the interrogation and stimulation of cell-cell adhesive junctions. This review covers established experimental techniques for stimulation and interrogation of cell-cell adhesion from cell pairs to monolayers.
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Affiliation(s)
- Ruiguo Yang
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588, United States
| | - Joshua A. Broussard
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
- Department of Dermatology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Kathleen J. Green
- Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
- Department of Dermatology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, United States
| | - Horacio D. Espinosa
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, United States
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL 60208, United States
- Institute for Cellular Engineering Technologies, Northwestern University, Evanston, IL 60208, United States
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180
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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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181
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Suffoletto K, Jetta D, Hua SZ. E-cadherin mediated lateral interactions between neighbor cells necessary for collective migration. J Biomech 2018; 71:159-166. [PMID: 29486895 DOI: 10.1016/j.jbiomech.2018.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 01/22/2018] [Accepted: 02/01/2018] [Indexed: 12/19/2022]
Abstract
Collective cell movement is critical in pathological processes such as wound healing and cancer invasion. It entails complex interactions between adjacent cells and between cells-extracellular matrices. Most studies measure the migration patterns and force propagation by placing cells on flat, patterned substrates. The cooperative behavior resulting from cell-cell interactions is not well understood. We have developed a multi-channel microfluidic device that has junctional protein E-cadherin coated onto the sidewalls of the channels that enables the cells' lateral interactions with their neighbors to be studied. Our study reveals that epithelial cells rely on lateral E-cadherin-based adhesions to maintain the cohesion of the group. Cells move faster in narrower channels, but the average velocity along the channels is reduced in E-cadherin coated channels versus non-adhesive channels. We have directly measured the forces in the cross-linking protein, alpha-actinin, using FRET sensors during cell migration, and found that higher tension exists at the cell edges adjacent to the walls coated with E-cadherin, the implication being E-cadherin transmits the shear forces but does not provide a driving force for this migration.
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Affiliation(s)
- Kevin Suffoletto
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, NY 14260, USA
| | - Deekshitha Jetta
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, NY 14260, USA
| | - Susan Z Hua
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, NY 14260, USA; Department of Physiology and Biophysics, SUNY-Buffalo, Buffalo, NY 14260, USA.
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182
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Sussman DM, Schwarz JM, Marchetti MC, Manning ML. Soft yet Sharp Interfaces in a Vertex Model of Confluent Tissue. PHYSICAL REVIEW LETTERS 2018; 120:058001. [PMID: 29481188 DOI: 10.1103/physrevlett.120.058001] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Indexed: 06/08/2023]
Abstract
How can dense biological tissue maintain sharp boundaries between coexisting cell populations? We explore this question within a simple vertex model for cells, focusing on the role of topology and tissue surface tension. We show that the ability of cells to independently regulate adhesivity and tension, together with neighbor-based interaction rules, lets them support strikingly unusual interfaces. In particular, we show that mechanical- and fluctuation-based measurements of the effective surface tension of a cellular aggregate yield different results, leading to mechanically soft interfaces that are nevertheless extremely sharp.
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Affiliation(s)
- Daniel M Sussman
- Department of Physics and Soft Matter Program, Syracuse University, Syracuse, New York 13244, USA
| | - J M Schwarz
- Department of Physics and Soft Matter Program, Syracuse University, Syracuse, New York 13244, USA
| | - M Cristina Marchetti
- Department of Physics and Soft Matter Program, Syracuse University, Syracuse, New York 13244, USA
| | - M Lisa Manning
- Department of Physics and Soft Matter Program, Syracuse University, Syracuse, New York 13244, USA
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183
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Coburn L, Lopez H, Schouwenaar IM, Yap AS, Lobaskin V, Gomez GA. Role of contact inhibition of locomotion and junctional mechanics in epithelial collective responses to injury. Phys Biol 2018; 15:024001. [PMID: 29091048 DOI: 10.1088/1478-3975/aa976b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epithelial tissues form physically integrated barriers against the external environment protecting organs from infection and invasion. Within each tissue, epithelial cells respond to different challenges that can potentially compromise tissue integrity. In particular, cells collectively respond to injuries by reorganizing their cell-cell junctions and migrating directionally towards the sites of damage. Notwithstanding, the mechanisms that drive collective responses in epithelial aggregates remain poorly understood. In this work, we develop a minimal mechanistic model that is able to capture the essential features of epithelial collective responses to injuries. We show that a model that integrates the mechanics of cells at the cell-cell and cell-substrate interfaces as well as contact inhibition of locomotion (CIL) correctly predicts two key properties of epithelial response to injury as: (1) local relaxation of the tissue and (2) collective reorganization involving the extension of cryptic lamellipodia that extend, on average, up to 3 cell diameters from the site of injury and morphometric changes in the basal regions. Our model also suggests that active responses (like the actomyosin purse string and softening of cell-cell junctions) are needed to drive morphometric changes in the apical region. Therefore, our results highlight the importance of the crosstalk between junctional biomechanics, cell substrate adhesion, and CIL, as well as active responses, in guiding the collective rearrangements that are required to preserve the epithelial barrier in response to injury.
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Affiliation(s)
- Luke Coburn
- Institute of Complex Systems and Mathematical Biology, University of Aberdeen, United Kingdom. Authors to whom any correspondence should be addressed
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184
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Liu Y, Galior K, Ma VPY, Salaita K. Molecular Tension Probes for Imaging Forces at the Cell Surface. Acc Chem Res 2017; 50:2915-2924. [PMID: 29160067 DOI: 10.1021/acs.accounts.7b00305] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mechanical forces are essential for a variety of biological processes ranging from transcription and translation to cell adhesion, migration, and differentiation. Through the activation of mechanosensitive signaling pathways, cells sense and respond to physical stimuli from the surrounding environment, a process widely known as mechanotransduction. At the cell membrane, many signaling receptors, such as integrins, cadherins and T- or B-cell receptors, bind to their ligands on the surface of adjacent cells or the extracellular matrix (ECM) to mediate mechanotransduction. Upon ligation, these receptor-ligand bonds transmit piconewton (pN) mechanical forces that are generated, in part, by the cytoskeleton. Importantly, these forces expose cryptic sites within mechanosensitive proteins and modulate the binding kinetics (on/off rate) of receptor-ligand complexes to further fine-tune mechanotransduction and the corresponding cell behavior. Over the past three decades, two categories of methods have been developed to measure cell receptor forces. The first class is traction force microscopy (TFM) and micropost array detectors (mPADs). In these methods, cells are cultured on elastic polymers or microstructures that deform under mechanical forces. The second category of techniques is single molecule force spectroscopy (SMFS) including atomic force microscopy (AFM), optical or magnetic tweezers, and biomembrane force probe (BFP). In SMFS, the experimenter applies external forces to probe the mechanics of individual cells or single receptor-ligand complexes, serially, one bond at a time. Although these techniques are powerful, the limited throughput of SMFS and the nN force sensitivity of TFM have hindered further elucidation of the molecular mechanisms of mechanotransduction. In this Account, we introduce the recent advent of molecular tension fluorescence microscopy (MTFM) as an emerging tool for molecular imaging of receptor mechanics in living cells. MTFM probes are composed of an extendable linker, such as polymer, oligonucleotide, or protein, and flanked by a fluorophore and quencher. By measuring the fluorescence emission of immobilized MTFM probes, one can infer the extension of the linker and the externally applied force. Thus, MTFM combines aspects of TFM and SMFS to optically report receptor forces across the entire cell surface with pN sensitivity. Specifically, we provide an in-depth review of MTFM probe design, which includes the extendable "spring", spectroscopic ruler, surface immobilization chemistry, and ligand design strategies. We also demonstrate the strengths and weaknesses of different versions of MTFM probes by discussing case studies involving the pN forces involved in epidermal growth factor receptor, integrin, and T-cell receptor signaling pathways. Lastly, we present a brief future outlook, primarily from a chemists' perspective, on the challenges and opportunities for the design of next generation MTFM probes.
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Affiliation(s)
- Yang Liu
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Kornelia Galior
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Victor Pui-Yan Ma
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Khalid Salaita
- Department
of Chemistry, Emory University, Atlanta, Georgia 30322, United States
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30332, United States
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185
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Kamran Z, Zellner K, Kyriazes H, Kraus CM, Reynier JB, Malamy JE. In vivo imaging of epithelial wound healing in the cnidarian Clytia hemisphaerica demonstrates early evolution of purse string and cell crawling closure mechanisms. BMC DEVELOPMENTAL BIOLOGY 2017; 17:17. [PMID: 29258421 PMCID: PMC5735930 DOI: 10.1186/s12861-017-0160-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/27/2017] [Indexed: 12/21/2022]
Abstract
Background All animals have mechanisms for healing damage to the epithelial sheets that cover the body and line internal cavities. Epithelial wounds heal either by cells crawling over the wound gap, by contraction of a super-cellular actin cable (“purse string”) that surrounds the wound, or some combination of the two mechanisms. Both cell crawling and purse string closure of epithelial wounds are widely observed across vertebrates and invertebrates, suggesting early evolution of these mechanisms. Cnidarians evolved ~600 million years ago and are considered a sister group to the Bilateria. They have been much studied for their tremendous regenerative potential, but epithelial wound healing has not been characterized in detail. Conserved elements of wound healing in bilaterians and cnidarians would suggest an evolutionary origin in a common ancestor. Here we test this idea by characterizing epithelial wound healing in live medusae of Clytia hemisphaerica. Results We identified cell crawling and purse string-mediated mechanisms of healing in Clytia epithelium that appear highly analogous of those seen in higher animals, suggesting that these mechanisms may have emerged in a common ancestor. Interestingly, we found that epithelial wound healing in Clytia is 75 to >600 times faster than in cultured cells or embryos of other animals previously studied, suggesting that Clytia may provide valuable clues about optimized healing efficiency. Finally, in Clytia, we show that damage to the basement membrane in a wound gap causes a rapid shift between the cell crawling and purse string mechanisms for wound closure. This is consistent with work in other systems showing that cells marginal to a wound choose between a super-cellular actin cable or lamellipodia formation to close wounds, and suggests a mechanism underlying this decision. Conclusions 1. Cell crawling and purse string mechanisms of epithelial wound healing likely evolved before the divergence of Cnidaria from the bilaterian lineage ~ 600mya 2. In Clytia, the choice between cell crawling and purse string mechanisms of wound healing depends on interactions between the epithelial cells and the basement membrane. Electronic supplementary material The online version of this article (10.1186/s12861-017-0160-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zach Kamran
- Biological Sciences Collegiate Division, The University of Chicago, 924 East 57th Street, Chicago, IL, 60637, USA
| | - Katie Zellner
- Biological Sciences Collegiate Division, The University of Chicago, 924 East 57th Street, Chicago, IL, 60637, USA
| | - Harry Kyriazes
- Niles North High School, District 219, 7700 Gross Point Rd., Skokie, IL, 60077, USA
| | - Christine M Kraus
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA
| | - Jean-Baptiste Reynier
- Biological Sciences Collegiate Division, The University of Chicago, 924 East 57th Street, Chicago, IL, 60637, USA
| | - Jocelyn E Malamy
- Department of Molecular Genetics and Cell Biology, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
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186
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Zhao J, Cao Y, DiPietro LA, Liang J. Dynamic cellular finite-element method for modelling large-scale cell migration and proliferation under the control of mechanical and biochemical cues: a study of re-epithelialization. J R Soc Interface 2017; 14:rsif.2016.0959. [PMID: 28404867 DOI: 10.1098/rsif.2016.0959] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/15/2017] [Indexed: 01/07/2023] Open
Abstract
Computational modelling of cells can reveal insight into the mechanisms of the important processes of tissue development. However, current cell models have limitations and are challenged to model detailed changes in cellular shapes and physical mechanics when thousands of migrating and interacting cells need to be modelled. Here we describe a novel dynamic cellular finite-element model (DyCelFEM), which accounts for changes in cellular shapes and mechanics. It also models the full range of cell motion, from movements of individual cells to collective cell migrations. The transmission of mechanical forces regulated by intercellular adhesions and their ruptures are also accounted for. Intra-cellular protein signalling networks controlling cell behaviours are embedded in individual cells. We employ DyCelFEM to examine specific effects of biochemical and mechanical cues in regulating cell migration and proliferation, and in controlling tissue patterning using a simplified re-epithelialization model of wound tissue. Our results suggest that biochemical cues are better at guiding cell migration with improved directionality and persistence, while mechanical cues are better at coordinating collective cell migration. Overall, DyCelFEM can be used to study developmental processes when a large population of migrating cells under mechanical and biochemical controls experience complex changes in cell shapes and mechanics.
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Affiliation(s)
- Jieling Zhao
- Department of Bioengineering, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Youfang Cao
- Theoretical Biology and Biophysics (T-6), Center for Nonlinear Studies (CNLS), Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Luisa A DiPietro
- Center for Wound Healing and Tissue Regeneration, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA
| | - Jie Liang
- Department of Bioengineering, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA
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187
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Vig DK, Hamby AE, Wolgemuth CW. Cellular Contraction Can Drive Rapid Epithelial Flows. Biophys J 2017; 113:1613-1622. [PMID: 28978451 DOI: 10.1016/j.bpj.2017.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 08/01/2017] [Accepted: 08/07/2017] [Indexed: 01/18/2023] Open
Abstract
Single, isolated epithelial cells move randomly; however, during wound healing, organism development, cancer metastasis, and many other multicellular phenomena, motile cells group into a collective and migrate persistently in a directed manner. Recent work has examined the physics and biochemistry that coordinates the motions of these groups of cells. Of late, two mechanisms have been touted as being crucial to the physics of these systems: leader cells and jamming. However, the actual importance of these to collective migration remains circumstantial. Fundamentally, collective behavior must arise from the actions of individual cells. Here, we show how biophysical activity of an isolated cell impacts collective dynamics in epithelial layers. Although many reports suggest that wound closure rates depend on isolated cell speed and/or leader cells, we find that these correlations are not universally true, nor do collective dynamics follow the trends suggested by models for jamming. Instead, our experimental data, when coupled with a mathematical model for collective migration, shows that intracellular contractile stress, isolated cell speed, and adhesion all play a substantial role in influencing epithelial dynamics, and that alterations in contraction and/or substrate adhesion can cause confluent epithelial monolayers to exhibit an increase in motility, a feature reminiscent of cancer metastasis. These results directly question the validity of wound-healing assays as a general means for measuring cell migration, and provide further insight into the salient physics of collective migration.
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Affiliation(s)
- Dhruv K Vig
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona
| | - Alex E Hamby
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona
| | - Charles W Wolgemuth
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona; Department of Physics, University of Arizona, Tucson, Arizona.
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188
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Sonavane PR, Wang C, Dzamba B, Weber GF, Periasamy A, DeSimone DW. Mechanical and signaling roles for keratin intermediate filaments in the assembly and morphogenesis of Xenopus mesendoderm tissue at gastrulation. Development 2017; 144:4363-4376. [PMID: 28982683 PMCID: PMC5769636 DOI: 10.1242/dev.155200] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 09/25/2017] [Indexed: 12/21/2022]
Abstract
The coordination of individual cell behaviors is a crucial step in the assembly and morphogenesis of tissues. Xenopus mesendoderm cells migrate collectively along a fibronectin (FN) substrate at gastrulation, but how the adhesive and mechanical forces required for these movements are generated and transmitted is unclear. Traction force microscopy (TFM) was used to establish that traction stresses are limited primarily to leading edge cells in mesendoderm explants, and that these forces are balanced by intercellular stresses in follower rows. This is further reflected in the morphology of these cells, with broad lamellipodial protrusions, mature focal adhesions and a gradient of activated Rac1 evident at the leading edge, while small protrusions, rapid turnover of immature focal adhesions and lack of a Rac1 activity gradient characterize cells in following rows. Depletion of keratin (krt8) with antisense morpholinos results in high traction stresses in follower row cells, misdirected protrusions and the formation of actin stress fibers anchored in streak-like focal adhesions. We propose that maintenance of mechanical integrity in the mesendoderm by keratin intermediate filaments is required to balance stresses within the tissue to regulate collective cell movements.
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Affiliation(s)
- Pooja R Sonavane
- Department of Cell Biology, School of Medicine, University of Virginia Health System, P.O. Box 800732, Charlottesville, VA 22908, USA
| | - Chong Wang
- Department of Cell Biology, School of Medicine, University of Virginia Health System, P.O. Box 800732, Charlottesville, VA 22908, USA
| | - Bette Dzamba
- Department of Cell Biology, School of Medicine, University of Virginia Health System, P.O. Box 800732, Charlottesville, VA 22908, USA
| | - Gregory F Weber
- Department of Cell Biology, School of Medicine, University of Virginia Health System, P.O. Box 800732, Charlottesville, VA 22908, USA
| | - Ammasi Periasamy
- Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Douglas W DeSimone
- Department of Cell Biology, School of Medicine, University of Virginia Health System, P.O. Box 800732, Charlottesville, VA 22908, USA
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189
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Veldhuis JH, Ehsandar A, Maître JL, Hiiragi T, Cox S, Brodland GW. Inferring cellular forces from image stacks. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0261. [PMID: 28348259 DOI: 10.1098/rstb.2016.0261] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2016] [Indexed: 12/18/2022] Open
Abstract
Although the importance of cellular forces to a wide range of embryogenesis and disease processes is widely recognized, measuring these forces is challenging, especially in three dimensions. Here, we introduce CellFIT-3D, a force inference technique that allows tension maps for three-dimensional cellular systems to be estimated from image stacks. Like its predecessors, video force microscopy and CellFIT, this cell mechanics technique assumes boundary-specific interfacial tensions to be the primary drivers, and it constructs force-balance equations based on triple junction (TJ) dihedral angles. The technique involves image processing, segmenting of cells, grouping of cell outlines, calculation of dihedral planes, averaging along three-dimensional TJs, and matrix equation assembly and solution. The equations tend to be strongly overdetermined, allowing indistinct TJs to be ignored and solution error estimates to be determined. Application to clean and noisy synthetic data generated using Surface Evolver gave tension errors of 1.6-7%, and analyses of eight-cell murine embryos gave estimated errors smaller than the 10% uncertainty of companion aspiration experiments. Other possible areas of application include morphogenesis, cancer metastasis and tissue engineering.This article is part of the themed issue 'Systems morphodynamics: understanding the development of tissue hardware'.
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Affiliation(s)
- Jim H Veldhuis
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Ahmad Ehsandar
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Jean-Léon Maître
- Department of Genetics and Developmental Biology, Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Takashi Hiiragi
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Simon Cox
- Department of Mathematics, Aberystwyth University, Aberystwyth, Ceredigion SY23 3BZ, UK
| | - G Wayne Brodland
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 .,Centre for Bioengineering and Biotechnology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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190
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Abstract
Biomaterials engineered with specific bioactive ligands, tunable mechanical properties, and complex architectural features have emerged as powerful tools to probe how cells sense and respond to the physical properties of their material surroundings, and ultimately provide designer approaches to control cell function.
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Affiliation(s)
- Linqing Li
- Biological Design Center and the Department of Biomedical Engineering, Boston University, Boston, Massachusetts, 02215, USA
- the Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, 02115, USA
| | - Jeroen Eyckmans
- Biological Design Center and the Department of Biomedical Engineering, Boston University, Boston, Massachusetts, 02215, USA
- the Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, 02115, USA
| | - Christopher S. Chen
- Biological Design Center and the Department of Biomedical Engineering, Boston University, Boston, Massachusetts, 02215, USA
- the Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, 02115, USA
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191
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Karsch S, Kong D, Großhans J, Janshoff A. Single-Cell Defects Cause a Long-Range Mechanical Response in a Confluent Epithelial Cell Layer. Biophys J 2017; 113:2601-2608. [PMID: 29129266 DOI: 10.1016/j.bpj.2017.10.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/05/2017] [Accepted: 10/16/2017] [Indexed: 02/06/2023] Open
Abstract
Epithelial cells are responsible for tissue homeostasis and form a barrier to maintain chemical gradients and mechanical integrity. Therefore, rapid wound closure is crucial for proper tissue function and restoring homeostasis. In this study, the mechanical properties of cells surrounding a single-cell wound are investigated during closure of the defect. The single-cell wound is induced in an intact layer using micropipette action and responses in neighboring cells are monitored with atomic force microscopy. Direct neighbors reveal a rise in the apparent pretension, which is dominated by cortical tension. The same effect was observed for a single-cell wound induced by laser ablation and during closure of a not fully confluent layer. Moreover, changes in the apparent pretension are far reaching and persist even in cells separated by three cell widths from the defect. This shows that epithelial cells respond to minimal wounds in a collective fashion by increased contractility with substantial reach.
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Affiliation(s)
- Susanne Karsch
- Institute for Physical Chemistry, University of Göttingen, Göttingen, Germany
| | - Deqing Kong
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Göttingen, Germany
| | - Jörg Großhans
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Göttingen, Germany
| | - Andreas Janshoff
- Institute for Physical Chemistry, University of Göttingen, Göttingen, Germany.
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192
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193
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Lin L, Zeng X. Numerical investigation of the role of intercellular interactions on collective epithelial cell migration. Biomech Model Mechanobiol 2017; 17:439-448. [PMID: 29094276 DOI: 10.1007/s10237-017-0970-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/16/2017] [Indexed: 11/26/2022]
Abstract
During collective cell migration, the intercellular forces will significantly affect the collective migratory behaviors. However, the measurement of mechanical stresses exerted at cell-cell junctions is very challenging. A recent experimental observation indicated that the intercellular adhesion sites within a migrating monolayer are subjected to both normal stress exerted perpendicular to cell-cell junction surface and shear stress exerted tangent to cell-cell junction surface. In this study, an interfacial interaction model was proposed to model the intercellular interactions for the first time. The intercellular interaction model-based study of collective epithelial migration revealed that the direction of cell migration velocity has better alignment with the orientation of local principal stress at higher maximum shear stress locations in an epithelial monolayer sheet. Parametric study of the effects of adhesion strength indicated that normal adhesion strength at the cell-cell junction surface has dominated effect on local alignment between the direction of cell velocity vector and the principal stress orientation, while the shear adhesion strength has little effect, which provides compelling evidence to help explain the force transmission via cell-cell junctions between adjacent cells in collective cell motion and provides new insights into "adhesive belt" effects at cell-cell junction.
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Affiliation(s)
- Liqiang Lin
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Xiaowei Zeng
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX, 78249, USA.
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194
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Alobaidi AA, Sun B. Probing three-dimensional collective cancer invasion with DIGME. CANCER CONVERGENCE 2017; 1:1. [PMID: 29623954 PMCID: PMC5876692 DOI: 10.1186/s41236-017-0004-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 09/14/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Multicellular pattern formation plays an important role in developmental biology, cancer metastasis and wound healing. While many physical factors have been shown to regulate these multicellular processes, the role of ECM micro-to-meso scale geometry has been poorly understood in 3D collective cancer invasion. RESULTS We have developed a mechanical-based strategy, Diskoid In Geometrically Micropatterned ECM (DIGME). DIGME allows easy engineering of the shape of 3D tissue organoid, the mesoscale ECM heterogeneity, and the fiber alignment of collagen-based ECM all at the same time. We have employed DIGME to study the 3D invasion of MDA-MB-231 diskoids in engineered collagen matrix. We find that the collective cancer invasion is closely regulated by the micro-to-meso scale geometry of the ECM. CONCLUSIONS We conclude that DIGME provides a simple yet powerful tool to probe 3D dynamics of tissue organoids in physically patterned microenvironments.
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Affiliation(s)
- Amani A. Alobaidi
- Department of Physics, Oregon State University, Weniger Hall, Corvallis, OR USA
| | - Bo Sun
- Department of Physics, Oregon State University, Weniger Hall, Corvallis, OR USA
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195
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Theveneau E, Linker C. Leaders in collective migration: are front cells really endowed with a particular set of skills? F1000Res 2017; 6:1899. [PMID: 29152225 PMCID: PMC5664975 DOI: 10.12688/f1000research.11889.1] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/28/2017] [Indexed: 12/21/2022] Open
Abstract
Collective cell migration is the coordinated movement emerging from the interaction of at least two cells. In multicellular organisms, collective cell migration is ubiquitous. During development, embryonic cells often travel in numbers, whereas in adults, epithelial cells close wounds collectively. There is often a division of labour and two categories of cells have been proposed: leaders and followers. These two terms imply that followers are subordinated to leaders whose proposed broad range of actions significantly biases the direction of the group of cells towards a specific target. These two terms are also tied to topology. Leaders are at the front while followers are located behind them. Here, we review recent work on some of the main experimental models for collective cell migration, concluding that leader-follower terminology may not be the most appropriate. It appears that not all collectively migrating groups are driven by cells located at the front. Moreover, the qualities that define leaders (pathfinding, traction forces and matrix remodelling) are not specific to front cells. These observations indicate that the terms leaders and followers are not suited to every case. We think that it would be more accurate to dissociate the function of a cell from its position in the group. The position of cells can be precisely defined with respect to the direction of movement by purely topological terms such as "front" or "rear" cells. In addition, we propose the more ample and strictly functional definition of "steering cells" which are able to determine the directionality of movement for the entire group. In this context, a leader cell represents only a specific case in which a steering cell is positioned at the front of the group.
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Affiliation(s)
- Eric Theveneau
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Claudia Linker
- Randall Division of Cell & Molecular Biophysics, King's College London, London, UK
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196
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Coupled circumferential and axial tension driven by actin and myosin influences in vivo axon diameter. Sci Rep 2017; 7:14188. [PMID: 29079766 PMCID: PMC5660205 DOI: 10.1038/s41598-017-13830-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/29/2017] [Indexed: 01/07/2023] Open
Abstract
It has long been known that neuronal axons are contractile. They actively maintain rest tension along the longitudinal direction both in vitro and in vivo. Here we show evidence that embryonic drosophila axons also actively maintain contractility/tension along the circumferential direction. We used confocal microscopy and spatial light interference microscopy to monitor axonal diameter along their length. We observed a decrease in diameter when microtubules are disrupted and an increase in diameter when actin filaments or myosin II are disrupted. Interestingly, active diameter reduction occurred consistently when axons were subjected to manipulations known to increase axial tension, suggesting that tension can be coupled in the axial and circumferential direction. This is further supported by the remarkably similar time constants for diameter reduction and rest tension increase of slackened axons. We infer that the actomyosin-driven circumferential contraction/hoop tension applies a squeezing force on the microtubule bundle of the axons. This hoop tension is balanced by the restoring force of the microtubule bundle. Therefore, axonal diameter increased when actin/myosin disrupting drugs relaxed the hoop tension and decreased when microtubule disrupting drug relaxed the restoring force. Circumferential tension thus can regulate axonal diameter and volume, as well as potentially microtubules alignment, inter-tubular spacing, and, by extension, axonal transport.
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197
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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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198
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Chen T, Zhao H, Gao L, Song L, Yang F, Du J. Hypotonicity promotes epithelial gap closure by lamellipodial protrusion. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 148:60-64. [PMID: 28962936 DOI: 10.1016/j.pbiomolbio.2017.09.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/11/2017] [Accepted: 09/25/2017] [Indexed: 01/24/2023]
Abstract
The closure of gaps within epithelia is an essential part of many physiological and pathological processes, such as embryonic development, organ remodeling and wound healing. Emerging evidence proved that the physical microenvironment plays important roles in cell behaviors. However, the effect of osmolarity of extracellular medium on gap closure is least understood. Using a gap closure model of epithelial cells, we found that hypotonic condition significantly facilitated the process of gap closure. Moreover, instead of actomyosin ring, enhanced migration leading by lamellipodia primarily contributed to the rapid gap closure in hypotonic condition. These findings provide insights for understanding the physiology of epithelial gap closure.
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Affiliation(s)
- T Chen
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China; Department of Orthopaedics, Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Guangxi 530027, People's Republic of China
| | - H Zhao
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China
| | - L Gao
- College of Life Science, Hebei Normal University, Heibei 050024, People's Republic of China
| | - L Song
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China; College of Life Science, Hebei Normal University, Heibei 050024, People's Republic of China
| | - F Yang
- Department of Orthopaedics, Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Guangxi 530027, People's Republic of China
| | - J Du
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, People's Republic of China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China.
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199
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Abstract
Recent findings suggest that mechanical forces strongly influence wound repair and fibrosis across multiple organ systems. Traction force is vital to the characterization of cellular responses to mechanical stimuli. Using hydrogel-based traction force microscopy, a FRET-based tension sensor, or microengineered cantilevers, the magnitude of traction forces can be measured. Here, we describe a traction force measurement methodology using a dense array of elastomeric microposts. This platform can be used to measure the traction force of a single cell or a colony of cells with or without geometric confinement.
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200
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Suñé-Auñón A, Jorge-Peñas A, Aguilar-Cuenca R, Vicente-Manzanares M, Van Oosterwyck H, Muñoz-Barrutia A. Full L 1-regularized Traction Force Microscopy over whole cells. BMC Bioinformatics 2017; 18:365. [PMID: 28797233 PMCID: PMC5550960 DOI: 10.1186/s12859-017-1771-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/30/2017] [Indexed: 12/21/2022] Open
Abstract
Background Traction Force Microscopy (TFM) is a widespread technique to estimate the tractions that cells exert on the surrounding substrate. To recover the tractions, it is necessary to solve an inverse problem, which is ill-posed and needs regularization to make the solution stable. The typical regularization scheme is given by the minimization of a cost functional, which is divided in two terms: the error present in the data or data fidelity term; and the regularization or penalty term. The classical approach is to use zero-order Tikhonov or L2-regularization, which uses the L2-norm for both terms in the cost function. Recently, some studies have demonstrated an improved performance using L1-regularization (L1-norm in the penalty term) related to an increase in the spatial resolution and sensitivity of the recovered traction field. In this manuscript, we present a comparison between the previous two regularization schemes (relying in the L2-norm for the data fidelity term) and the full L1-regularization (using the L1-norm for both terms in the cost function) for synthetic and real data. Results Our results reveal that L1-regularizations give an improved spatial resolution (more important for full L1-regularization) and a reduction in the background noise with respect to the classical zero-order Tikhonov regularization. In addition, we present an approximation, which makes feasible the recovery of cellular tractions over whole cells on typical full-size microscope images when working in the spatial domain. Conclusions The proposed full L1-regularization improves the sensitivity to recover small stress footprints. Moreover, the proposed method has been validated to work on full-field microscopy images of real cells, what certainly demonstrates it is a promising tool for biological applications. Electronic supplementary material The online version of this article (doi:10.1186/s12859-017-1771-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alejandro Suñé-Auñón
- Bioengineering and Aerospace Engineering Department, Universidad Carlos III de Madrid, Leganés, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, 28911, Madrid, Spain
| | - Alvaro Jorge-Peñas
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, 3001, Leuven, Belgium
| | - Rocío Aguilar-Cuenca
- Instituto de Investigación Sanitaria-Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, School of Medicine, 28006, Madrid, Spain
| | - Miguel Vicente-Manzanares
- Instituto de Investigación Sanitaria-Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, School of Medicine, 28006, Madrid, Spain
| | - Hans Van Oosterwyck
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, 3001, Leuven, Belgium.,Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, Leuven, Belgium
| | - Arrate Muñoz-Barrutia
- Bioengineering and Aerospace Engineering Department, Universidad Carlos III de Madrid, Leganés, Spain. .,Instituto de Investigación Sanitaria Gregorio Marañón, 28911, Madrid, Spain.
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