101
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Lam PY, Mangos S, Green JM, Reiser J, Huttenlocher A. In vivo imaging and characterization of actin microridges. PLoS One 2015; 10:e0115639. [PMID: 25629723 PMCID: PMC4309568 DOI: 10.1371/journal.pone.0115639] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 11/25/2014] [Indexed: 11/19/2022] Open
Abstract
Actin microridges form labyrinth like patterns on superficial epithelial cells across animal species. This highly organized assembly has been implicated in mucus retention and in the mechanical structure of mucosal surfaces, however the mechanisms that regulate actin microridges remain largely unknown. Here we characterize the composition and dynamics of actin microridges on the surface of zebrafish larvae using live imaging. Microridges contain phospho-tyrosine, cortactin and VASP, but not focal adhesion kinase. Time-lapse imaging reveals dynamic changes in the length and branching of microridges in intact animals. Transient perturbation of the microridge pattern occurs before cell division with rapid re-assembly during and after cytokinesis. Microridge assembly is maintained with constitutive activation of Rho or inhibition of myosin II activity. However, expression of dominant negative RhoA or Rac alters microridge organization, with an increase in distance between microridges. Latrunculin A treatment and photoconversion experiments suggest that the F-actin filaments are actively treadmilling in microridges. Accordingly, inhibition of Arp2/3 or PI3K signaling impairs microridge structure and length. Taken together, actin microridges in zebrafish represent a tractable in vivo model to probe pattern formation and dissect Arp2/3-mediated actin dynamics in vivo.
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Affiliation(s)
- Pui-ying Lam
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, United States of America
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706, United States of America
| | - Steve Mangos
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL 60612, United States of America
| | - Julie M. Green
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, United States of America
| | - Jochen Reiser
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL 60612, United States of America
| | - Anna Huttenlocher
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, United States of America
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, United States of America
- * E-mail:
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102
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Tug of war--the influence of opposing physical forces on epithelial cell morphology. Dev Biol 2015; 401:92-102. [PMID: 25576028 DOI: 10.1016/j.ydbio.2014.12.030] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 12/24/2014] [Accepted: 12/28/2014] [Indexed: 01/13/2023]
Abstract
The shape of a single animal cell is determined both by its internal cytoskeleton and through physical interactions with its environment. In a tissue context, this extracellular environment is made up largely of other cells and the extracellular matrix. As a result, the shape of cells residing within an epithelium will be determined both by forces actively generated within the cells themselves and by their deformation in response to forces generated elsewhere in the tissue as they propagate through cell-cell junctions. Together these complex patterns of forces combine to drive epithelial tissue morphogenesis during both development and homeostasis. Here we review the role of both active and passive cell shape changes and mechanical feedback control in tissue morphogenesis in different systems.
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103
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R. Noppe A, Roberts AP, Yap AS, Gomez GA, Neufeld Z. Modelling wound closure in an epithelial cell sheet using the cellular Potts model. Integr Biol (Camb) 2015; 7:1253-64. [DOI: 10.1039/c5ib00053j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We use a two-dimensional cellular Potts model to represent the behavior of an epithelial cell layer and describe its dynamics in response to a microscopic wound.
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Affiliation(s)
- Adrian R. Noppe
- School of Mathematics and Physics
- The University of Queensland
- Brisbane
- Australia 4072
| | - Anthony P. Roberts
- School of Mathematics and Physics
- The University of Queensland
- Brisbane
- Australia 4072
| | - Alpha S. Yap
- Institute for Molecular Bioscience
- Division of Cell Biology and Molecular Medicine
- The University of Queensland
- Brisbane
- Australia 4072
| | - Guillermo A. Gomez
- Institute for Molecular Bioscience
- Division of Cell Biology and Molecular Medicine
- The University of Queensland
- Brisbane
- Australia 4072
| | - Zoltan Neufeld
- School of Mathematics and Physics
- The University of Queensland
- Brisbane
- Australia 4072
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104
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The Toll/NF-κB signaling pathway is required for epidermal wound repair in Drosophila. Proc Natl Acad Sci U S A 2014; 111:E5373-82. [PMID: 25427801 DOI: 10.1073/pnas.1408224111] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Toll/NF-κB pathway, first identified in studies of dorsal-ventral polarity in the early Drosophila embryo, is well known for its role in the innate immune response. Here, we reveal that the Toll/NF-κB pathway is essential for wound closure in late Drosophila embryos. Toll mutants and Dif dorsal (NF-κB) double mutants are unable to repair epidermal gaps. Dorsal is activated on wounding, and Dif and Dorsal are required for the sustained down-regulation of E-cadherin, an obligatory component of the adherens junctions (AJs), at the wound edge. This remodeling of the AJs promotes the assembly of an actin-myosin cable at the wound margin; contraction of the actin cable, in turn, closes the wound. In the absence of Toll or Dif and dorsal (dl), both E-cadherin down-regulation and actin-cable formation fail, thus resulting in open epidermal gaps. Given the conservation of the Toll/NF-κB pathway in mammals and the epithelial expression of many components of the pathway, this function in wound healing is likely to be conserved in vertebrates.
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105
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Zhou Z, Munteanu EL, He J, Ursell T, Bathe M, Huang KC, Chang F. The contractile ring coordinates curvature-dependent septum assembly during fission yeast cytokinesis. Mol Biol Cell 2014; 26:78-90. [PMID: 25355954 PMCID: PMC4279231 DOI: 10.1091/mbc.e14-10-1441] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cytokinesis in fission yeast is accomplished by inward growth of the cell wall septum guided by the contractile ring. The ring promotes local septum growth in a curvature-dependent manner, allowing even a misshapen septum to grow into a more regular shape. This suggests that the ring regulates cell wall assembly through a mechanosensitive mechanism. The functions of the actin-myosin–based contractile ring in cytokinesis remain to be elucidated. Recent findings show that in the fission yeast Schizosaccharomyces pombe, cleavage furrow ingression is driven by polymerization of cell wall fibers outside the plasma membrane, not by the contractile ring. Here we show that one function of the ring is to spatially coordinate septum cell wall assembly. We develop an improved method for live-cell imaging of the division apparatus by orienting the rod-shaped cells vertically using microfabricated wells. We observe that the septum hole and ring are circular and centered in wild-type cells and that in the absence of a functional ring, the septum continues to ingress but in a disorganized and asymmetric manner. By manipulating the cleavage furrow into different shapes, we show that the ring promotes local septum growth in a curvature-dependent manner, allowing even a misshapen septum to grow into a more regular shape. This curvature-dependent growth suggests a model in which contractile forces of the ring shape the septum cell wall by stimulating the cell wall machinery in a mechanosensitive manner. Mechanical regulation of the cell wall assembly may have general relevance to the morphogenesis of walled cells.
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Affiliation(s)
- Zhou Zhou
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032
| | - Emilia Laura Munteanu
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032
| | - Jun He
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Tristan Ursell
- Department of Bioengineering, Stanford University, Stanford, CA 94305
| | - Mark Bathe
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305 Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Fred Chang
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032
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106
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Abstract
Cells are always subjected to mechanical stresses, resulting in wounds of the cell membrane, but cells are able to repair and reseal their wounded membrane. Previous reports have shown that actin and myosin II accumulate around the wound and that the constriction of this purse-string closes the membrane pore. Here, we developed a microsurgical wound assay to assess wound repair in Dictyostelium cells. Fluorescent dye that had been incorporated into the cells leaked out for only 2-3 sec after wounding, and a GFP-derived, fluorescent Ca(2+) sensor showed that intracellular Ca(2+) transiently increased immediately after wounding. In the absence of external Ca(2+), the cell failed to repair itself. During the repair process, actin accumulated at the wounded sites but myosin II did not. The wounds were repaired even in myosin II null cells to a comparable degree as the wild-type cells, suggesting that myosin II does not contribute to wound repair. Thus, the actomyosin purse-string constriction model is not a common mechanism for wound repair in eukaryotic cells, and this discrepancy may arise from the difference in cell size.
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Affiliation(s)
- Shigehiko Yumura
- Department of Functional Molecular Biology, Graduate School of Medicine, Yamaguchi University, Yamaguchi 753-8512, Japan
| | - Sayaka Hashima
- Department of Functional Molecular Biology, Graduate School of Medicine, Yamaguchi University, Yamaguchi 753-8512, Japan
| | - Satsuki Muranaka
- Department of Functional Molecular Biology, Graduate School of Medicine, Yamaguchi University, Yamaguchi 753-8512, Japan
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107
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Hu B, Shi W, Wu YL, Leow WR, Cai P, Li S, Chen X. Orthogonally engineering matrix topography and rigidity to regulate multicellular morphology. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5786-5793. [PMID: 25066463 DOI: 10.1002/adma.201402489] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Indexed: 06/03/2023]
Abstract
Programmable polymer substrates, which mimic the variable extracellular matrices in living systems, are used to regulate multicellular morphology, via orthogonally modulating the matrix topography and elasticity. The multicellular morphology is dependent on the competition between cell-matrix adhesion and cell-cell adhesion. Decreasing the cell-matrix adhesion provokes cytoskeleton reorganization, inhibits lamellipodial crawling, and thus enhances the leakiness of multicellular morphology.
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Affiliation(s)
- Benhui Hu
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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108
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Border forces and friction control epithelial closure dynamics. Biophys J 2014; 106:65-73. [PMID: 24411238 DOI: 10.1016/j.bpj.2013.11.015] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 10/30/2013] [Accepted: 11/06/2013] [Indexed: 02/08/2023] Open
Abstract
We study the closure dynamics of a large number of well-controlled circular apertures within an epithelial monolayer, where the collective cell migration responsible for epithelization is triggered by the removal of a spatial constraint rather than by scratching. Based on experimental observations, we propose a physical model that takes into account border forces, friction with the substrate, and tissue rheology. Border protrusive activity drives epithelization despite the presence of a contractile actomyosin cable at the periphery of the wound. The closure dynamics is quantified by an epithelization coefficient, defined as the ratio of protrusive stress to tissue-substrate friction, that allows classification of different phenotypes. The same analysis demonstrates a distinct signature for human cells bearing the oncogenic RasV12 mutation, demonstrating the potential of the approach to quantitatively characterize metastatic transformations.
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109
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Brugués A, Anon E, Conte V, Veldhuis JH, Gupta M, Colombelli J, Muñoz JJ, Brodland GW, Ladoux B, Trepat X. Forces driving epithelial wound healing. NATURE PHYSICS 2014; 10:683-690. [PMID: 27340423 PMCID: PMC4915550 DOI: 10.1038/nphys3040] [Citation(s) in RCA: 270] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A fundamental feature of multicellular organisms is their ability to self-repair wounds through the movement of epithelial cells into the damaged area. This collective cellular movement is commonly attributed to a combination of cell crawling and "purse-string" contraction of a supracellular actomyosin ring. Here we show by direct experimental measurement that these two mechanisms are insufficient to explain force patterns observed during wound closure. At early stages of the process, leading actin protrusions generate traction forces that point away from the wound, showing that wound closure is initially driven by cell crawling. At later stages, we observed unanticipated patterns of traction forces pointing towards the wound. Such patterns have strong force components that are both radial and tangential to the wound. We show that these force components arise from tensions transmitted by a heterogeneous actomyosin ring to the underlying substrate through focal adhesions. The structural and mechanical organization reported here provides cells with a mechanism to close the wound by cooperatively compressing the underlying substrate.
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Affiliation(s)
- Agustí Brugués
- Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Ester Anon
- Institute for Bioengineering of Catalonia, Barcelona, Spain
- Institut Jacques Monod (IJM), Université Paris Diderot, and Unité Mixte de Recherche 7592 CNRS, Paris, France
| | - Vito Conte
- Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Jim H. Veldhuis
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Mukund Gupta
- Mechanobiology Institute (MBI), National University of Singapore, Singapore
| | - Julien Colombelli
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
| | - José J. Muñoz
- Laboratori de Càlcul Numèric, Department of Applied Mathematics III, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - G. Wayne Brodland
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Benoit Ladoux
- Institut Jacques Monod (IJM), Université Paris Diderot, and Unité Mixte de Recherche 7592 CNRS, Paris, France
- Mechanobiology Institute (MBI), National University of Singapore, Singapore
- Corresponding authors: Prof. Xavier Trepat, Institute for Bioengineering of Catalonia C/ Baldiri Reixac 15-21 Barcelona 08028 Spain Tel: +34934020265 ; Prof. Benoit Ladoux Institut Jacques Monod, Université Paris Diderot & CNRS UMR 7592 Batiment Buffon 15 rue Hélène Brion 75013 Paris, France
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, and CIBERES, Spain
- Corresponding authors: Prof. Xavier Trepat, Institute for Bioengineering of Catalonia C/ Baldiri Reixac 15-21 Barcelona 08028 Spain Tel: +34934020265 ; Prof. Benoit Ladoux Institut Jacques Monod, Université Paris Diderot & CNRS UMR 7592 Batiment Buffon 15 rue Hélène Brion 75013 Paris, France
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110
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Muñoz-Soriano V, López-Domenech S, Paricio N. Why mammalian wound-healing researchers may wish to turn toDrosophilaas a model. Exp Dermatol 2014; 23:538-42. [DOI: 10.1111/exd.12472] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2014] [Indexed: 01/10/2023]
Affiliation(s)
- Verónica Muñoz-Soriano
- Departamento de Genética; Facultad CC Biológicas; Universidad de Valencia; Burjasot Spain
| | - Sandra López-Domenech
- Departamento de Genética; Facultad CC Biológicas; Universidad de Valencia; Burjasot Spain
| | - Nuria Paricio
- Departamento de Genética; Facultad CC Biológicas; Universidad de Valencia; Burjasot Spain
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111
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Krautz R, Arefin B, Theopold U. Damage signals in the insect immune response. FRONTIERS IN PLANT SCIENCE 2014; 5:342. [PMID: 25071815 PMCID: PMC4093659 DOI: 10.3389/fpls.2014.00342] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 06/26/2014] [Indexed: 05/24/2023]
Abstract
Insects and mammals share an ancient innate immune system comprising both humoral and cellular responses. The insect immune system consists of the fat body, which secretes effector molecules into the hemolymph and several classes of hemocytes, which reside in the hemolymph and of protective border epithelia. Key features of wound- and immune responses are shared between insect and mammalian immune systems including the mode of activation by commonly shared microbial (non-self) patterns and the recognition of these patterns by dedicated receptors. It is unclear how metazoan parasites in insects, which lack these shared motifs, are recognized. Research in recent years has demonstrated that during entry into the insect host, many eukaryotic pathogens leave traces that alert potential hosts of the damage they have afflicted. In accordance with terminology used in the mammalian immune systems, these signals have been dubbed danger- or damage-associated signals. Damage signals are necessary byproducts generated during entering hosts either by mechanical or proteolytic damage. Here, we briefly review the current stage of knowledge on how wound closure and wound healing during mechanical damage is regulated and how damage-related signals contribute to these processes. We also discuss how sensors of proteolytic activity induce insect innate immune responses. Strikingly damage-associated signals are also released from cells that have aberrant growth, including tumor cells. These signals may induce apoptosis in the damaged cells, the recruitment of immune cells to the aberrant tissue and even activate humoral responses. Thus, this ensures the removal of aberrant cells and compensatory proliferation to replace lost tissue. Several of these pathways may have been co-opted from wound healing and developmental processes.
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Affiliation(s)
| | | | - Ulrich Theopold
- *Correspondence: Ulrich Theopold, Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Svante Arrheniusväg 20C, Stockholm, Sweden e-mail:
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112
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Palmyre A, Lee J, Ryklin G, Camarata T, Selig MK, Duchemin AL, Nowak P, Arnaout MA, Drummond IA, Vasilyev A. Collective epithelial migration drives kidney repair after acute injury. PLoS One 2014; 9:e101304. [PMID: 25010471 PMCID: PMC4092191 DOI: 10.1371/journal.pone.0101304] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 06/04/2014] [Indexed: 02/07/2023] Open
Abstract
Acute kidney injury (AKI) is a common and significant medical problem. Despite the kidney’s remarkable regenerative capacity, the mortality rate for the AKI patients is high. Thus, there remains a need to better understand the cellular mechanisms of nephron repair in order to develop new strategies that would enhance the intrinsic ability of kidney tissue to regenerate. Here, using a novel, laser ablation-based, zebrafish model of AKI, we show that collective migration of kidney epithelial cells is a primary early response to acute injury. We also show that cell proliferation is a late response of regenerating kidney epithelia that follows cell migration during kidney repair. We propose a computational model that predicts this temporal relationship and suggests that cell stretch is a mechanical link between migration and proliferation, and present experimental evidence in support of this hypothesis. Overall, this study advances our understanding of kidney repair mechanisms by highlighting a primary role for collective cell migration, laying a foundation for new approaches to treatment of AKI.
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Affiliation(s)
- Aurélien Palmyre
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Jeongeun Lee
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Biomedical Sciences, NYIT COM, Old Westbury, New York, United States of America
| | - Gennadiy Ryklin
- Department of Biomedical Sciences, NYIT COM, Old Westbury, New York, United States of America
| | - Troy Camarata
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Martin K. Selig
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Anne-Laure Duchemin
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Paul Nowak
- Department of Biomedical Sciences, NYIT COM, Old Westbury, New York, United States of America
| | - M. Amin Arnaout
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Developmental and Regenerative Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Iain A. Drummond
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Aleksandr Vasilyev
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Department of Biomedical Sciences, NYIT COM, Old Westbury, New York, United States of America
- * E-mail:
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113
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Zulueta-Coarasa T, Tamada M, Lee EJ, Fernandez-Gonzalez R. Automated multidimensional image analysis reveals a role for Abl in embryonic wound repair. Development 2014; 141:2901-11. [PMID: 24948602 DOI: 10.1242/dev.106898] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The embryonic epidermis displays a remarkable ability to repair wounds rapidly. Embryonic wound repair is driven by the evolutionary conserved redistribution of cytoskeletal and junctional proteins around the wound. Drosophila has emerged as a model to screen for factors implicated in wound closure. However, genetic screens have been limited by the use of manual analysis methods. We introduce MEDUSA, a novel image-analysis tool for the automated quantification of multicellular and molecular dynamics from time-lapse confocal microscopy data. We validate MEDUSA by quantifying wound closure in Drosophila embryos, and we show that the results of our automated analysis are comparable to analysis by manual delineation and tracking of the wounds, while significantly reducing the processing time. We demonstrate that MEDUSA can also be applied to the investigation of cellular behaviors in three and four dimensions. Using MEDUSA, we find that the conserved nonreceptor tyrosine kinase Abelson (Abl) contributes to rapid embryonic wound closure. We demonstrate that Abl plays a role in the organization of filamentous actin and the redistribution of the junctional protein β-catenin at the wound margin during embryonic wound repair. Finally, we discuss different models for the role of Abl in the regulation of actin architecture and adhesion dynamics at the wound margin.
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Affiliation(s)
- Teresa Zulueta-Coarasa
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada M5S 3G9
| | - Masako Tamada
- Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Eun J Lee
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada M5S 3G9
| | - Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada M5S 3G9 Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada M5S 3G5 Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada M5G 1X8
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114
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Swope D, Kramer J, King TR, Cheng YS, Kramer SG. Cdc42 is required in a genetically distinct subset of cardiac cells during Drosophila dorsal vessel closure. Dev Biol 2014; 392:221-32. [PMID: 24949939 DOI: 10.1016/j.ydbio.2014.05.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/19/2014] [Accepted: 05/29/2014] [Indexed: 10/25/2022]
Abstract
The embryonic heart tube is formed by the migration and subsequent midline convergence of two bilateral heart fields. In Drosophila the heart fields are organized into two rows of cardioblasts (CBs). While morphogenesis of the dorsal ectoderm, which lies directly above the Drosophila dorsal vessel (DV), has been extensively characterized, the migration and concomitant fundamental factors facilitating DV formation remain poorly understood. Here we provide evidence that DV closure occurs at multiple independent points along the A-P axis of the embryo in a "buttoning" pattern, divergent from the zippering mechanism observed in the overlying epidermis during dorsal closure. Moreover, we demonstrate that a genetically distinct subset of CBs is programmed to make initial contact with the opposing row. To elucidate the cellular mechanisms underlying this process, we examined the role of Rho GTPases during cardiac migration using inhibitory and overexpression approaches. We found that Cdc42 shows striking cell-type specificity during DV formation. Disruption of Cdc42 function specifically prevents CBs that express the homeobox gene tinman from completing their dorsal migration, resulting in a failure to make connections with their partnering CBs. Conversely, neighboring CBs that express the orphan nuclear receptor, seven-up, are not sensitive to Cdc42 inhibition. Furthermore, this phenotype was specific to Cdc42 and was not observed upon perturbation of Rac or Rho function. Together with the observation that DV closure occurs through the initial contralateral pairing of tinman-expressing CBs, our studies suggest that the distinct buttoning mechanism we propose for DV closure is elaborated through signaling pathways regulating Cdc42 activity in this cell type.
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Affiliation(s)
- David Swope
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Joseph Kramer
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Tiffany R King
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA; Graduate Program in Cell and Developmental Biology, Rutgers Graduate School of Biomedical Sciences at Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Yi-Shan Cheng
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Sunita G Kramer
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA; Graduate Program in Cell and Developmental Biology, Rutgers Graduate School of Biomedical Sciences at Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA.
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115
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Tsarouhas V, Yao L, Samakovlis C. Src kinases and ERK activate distinct responses to Stitcher receptor tyrosine kinase signaling during wound healing in Drosophila. J Cell Sci 2014; 127:1829-39. [DOI: 10.1242/jcs.143016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
Metazoans have evolved efficient mechanisms for epidermal repair and survival following injury. Several cellular responses and key signaling molecules that are involved in wound healing have been identified in Drosophila, but the coordination of cytoskeletal rearrangements and the activation of gene expression during barrier repair are poorly understood. The Ret-like receptor tyrosine kinase (RTK) Stitcher (Stit, also known as Cad96Ca) regulates both re-epithelialization and transcriptional activation by Grainy head (Grh) to induce restoration of the extracellular barrier. Here, we describe the immediate downstream effectors of Stit signaling in vivo. Drk (Downstream of receptor kinase) and Src family tyrosine kinases bind to the same docking site in the Stit intracellular domain. Drk is required for the full activation of transcriptional responses but is dispensable for re-epithelialization. By contrast, Src family kinases (SFKs) control both the assembly of a contractile actin ring at the wound periphery and Grh-dependent activation of barrier-repair genes. Our analysis identifies distinct pathways mediating injury responses and reveals an RTK-dependent activation mode for Src kinases and their central functions during epidermal wound healing in vivo.
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Affiliation(s)
- Vasilios Tsarouhas
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-10691 Stockholm, Sweden
| | - Liqun Yao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-10691 Stockholm, Sweden
| | - Christos Samakovlis
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, S-10691 Stockholm, Sweden
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Wang L, Kounatidis I, Ligoxygakis P. Drosophila as a model to study the role of blood cells in inflammation, innate immunity and cancer. Front Cell Infect Microbiol 2014; 3:113. [PMID: 24409421 PMCID: PMC3885817 DOI: 10.3389/fcimb.2013.00113] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/21/2013] [Indexed: 01/07/2023] Open
Abstract
Drosophila has a primitive yet effective blood system with three types of haemocytes which function throughout different developmental stages and environmental stimuli. Haemocytes play essential roles in tissue modeling during embryogenesis and morphogenesis, and also in innate immunity. The open circulatory system of Drosophila makes haemocytes ideal signal mediators to cells and tissues in response to events such as infection and wounding. The application of recently developed and sophisticated genetic tools to the relatively simple genome of Drosophila has made the fly a popular system for modeling human tumorigensis and metastasis. Drosophila is now used for screening and investigation of genes implicated in human leukemia and also in modeling development of solid tumors. This second line of research offers promising opportunities to determine the seemingly conflicting roles of blood cells in tumor progression and invasion. This review provides an overview of the signaling pathways conserved in Drosophila during haematopoiesis, haemostasis, innate immunity, wound healing and inflammation. We also review the most recent progress in the use of Drosophila as a cancer research model with an emphasis on the roles haemocytes can play in various cancer models and in the links between inflammation and cancer.
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Affiliation(s)
- Lihui Wang
- Laboratory of Genes and Development, Department of Biochemistry, University of Oxford Oxford, UK
| | - Ilias Kounatidis
- Laboratory of Genes and Development, Department of Biochemistry, University of Oxford Oxford, UK
| | - Petros Ligoxygakis
- Laboratory of Genes and Development, Department of Biochemistry, University of Oxford Oxford, UK
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Losick VP, Fox DT, Spradling AC. Polyploidization and cell fusion contribute to wound healing in the adult Drosophila epithelium. Curr Biol 2013; 23:2224-2232. [PMID: 24184101 PMCID: PMC3898104 DOI: 10.1016/j.cub.2013.09.029] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/19/2013] [Accepted: 09/13/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND Reestablishing epithelial integrity and biosynthetic capacity is critically important following tissue damage. The adult Drosophila abdominal epithelium provides an attractive new system to address how postmitotic diploid cells contribute to repair. RESULTS Puncture wounds to the adult Drosophila epidermis close initially by forming a melanized scab. We found that epithelial cells near the wound site fuse to form a giant syncytium, which sends lamellae under the scab to re-epithelialize the damaged site. Other large cells arise more peripherally by initiating endocycles and becoming polyploid, or by cell fusion. Rac GTPase activity is needed for syncytium formation, while the Hippo signaling effector Yorkie modulates both polyploidization and cell fusion. Large cell formation is functionally important because when both polyploidization and fusion are blocked, wounds do not re-epithelialize. CONCLUSIONS Our observations indicate that cell mass lost upon wounding can be replaced by polyploidization instead of mitotic proliferation. We propose that large cells generated by polyploidization or cell fusion are essential because they are better able than diploid cells to mechanically stabilize wounds, especially those containing permanent acellular structures, such as scar tissue.
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Affiliation(s)
- Vicki P Losick
- Department of Embryology, Carnegie Institution for Science, Howard Hughes Medical Institute, 3520 San Martin Drive, Baltimore, MD 21218, USA
| | - Donald T Fox
- Department of Pharmacology and Cancer Biology and Department of Cell Biology, Duke University Medical Center, C318 LSRC Box 3813, Durham, NC 27710, USA
| | - Allan C Spradling
- Department of Embryology, Carnegie Institution for Science, Howard Hughes Medical Institute, 3520 San Martin Drive, Baltimore, MD 21218, USA.
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Li J, Zhang S, Soto X, Woolner S, Amaya E. ERK and phosphoinositide 3-kinase temporally coordinate different modes of actin-based motility during embryonic wound healing. J Cell Sci 2013; 126:5005-17. [PMID: 23986484 PMCID: PMC3820245 DOI: 10.1242/jcs.133421] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Embryonic wound healing provides a perfect example of efficient recovery of tissue integrity and homeostasis, which is vital for survival. Tissue movement in embryonic wound healing requires two functionally distinct actin structures: a contractile actomyosin cable and actin protrusions at the leading edge. Here, we report that the discrete formation and function of these two structures is achieved by the temporal segregation of two intracellular upstream signals and distinct downstream targets. The sequential activation of ERK and phosphoinositide 3-kinase (PI3K) signalling divides Xenopus embryonic wound healing into two phases. In the first phase, activated ERK suppresses PI3K activity, and is responsible for the activation of Rho and myosin-2, which drives actomyosin cable formation and constriction. The second phase is dominated by restored PI3K signalling, which enhances Rac and Cdc42 activity, leading to the formation of actin protrusions that drive migration and zippering. These findings reveal a new mechanism for coordinating different modes of actin-based motility in a complex tissue setting, namely embryonic wound healing.
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Affiliation(s)
- Jingjing Li
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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Fernandez-Gonzalez R, Zallen JA. Wounded cells drive rapid epidermal repair in the early Drosophila embryo. Mol Biol Cell 2013; 24:3227-37. [PMID: 23985320 PMCID: PMC3806660 DOI: 10.1091/mbc.e13-05-0228] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Epithelial tissues are protective barriers that display a remarkable ability to repair wounds. Wound repair is often associated with an accumulation of actin and nonmuscle myosin II around the wound, forming a purse string. The role of actomyosin networks in generating mechanical force during wound repair is not well understood. Here we investigate the mechanisms of force generation during wound repair in the epidermis of early and late Drosophila embryos. We find that wound closure is faster in early embryos, where, in addition to a purse string around the wound, actomyosin networks at the medial cortex of the wounded cells contribute to rapid wound repair. Laser ablation demonstrates that both medial and purse-string actomyosin networks generate contractile force. Quantitative analysis of protein localization dynamics during wound closure indicates that the rapid contraction of medial actomyosin structures during wound repair in early embryos involves disassembly of the actomyosin network. By contrast, actomyosin purse strings in late embryos contract more slowly in a mechanism that involves network condensation. We propose that the combined action of two force-generating structures--a medial actomyosin network and an actomyosin purse string--contributes to the increased efficiency of wound repair in the early embryo.
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Affiliation(s)
- Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering and Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G9, Canada Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada Howard Hughes Medical Institute, Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065
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Abstract
Changes in cell shape are one of the driving forces of tissue morphogenesis. Contractile cytoskeletal assemblies based on actomyosin networks have emerged as a main player that can drive these changes. Different types of actomyosin networks have been identified, with distinct subcellular localizations, including apical junctional and apicomedial actomyosin. A further specialization of junctional actomyosin are so-called actomyosin 'cables', supracellular arrangements that appear to stretch over many cell diameters. Such actomyosin cables have been shown to serve several important functions, in processes such as wound healing, epithelial morphogenesis and maintenance of compartment identities during development. In the Drosophila embryo, we have recently identified a function for a circumferential actomyosin cable in assisting tube formation. Here, I will briefly summarize general principles that have emerged from the analysis of such cables.
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Affiliation(s)
- Katja Röper
- MRC-Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
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