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Méhes E, Mones E, Varga M, Zsigmond Á, Biri-Kovács B, Nyitray L, Barone V, Krens G, Heisenberg CP, Vicsek T. 3D cell segregation geometry and dynamics are governed by tissue surface tension regulation. Commun Biol 2023; 6:817. [PMID: 37542157 PMCID: PMC10403547 DOI: 10.1038/s42003-023-05181-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023] Open
Abstract
Tissue morphogenesis and patterning during development involve the segregation of cell types. Segregation is driven by differential tissue surface tensions generated by cell types through controlling cell-cell contact formation by regulating adhesion and actomyosin contractility-based cellular cortical tensions. We use vertebrate tissue cell types and zebrafish germ layer progenitors as in vitro models of 3-dimensional heterotypic segregation and developed a quantitative analysis of their dynamics based on 3D time-lapse microscopy. We show that general inhibition of actomyosin contractility by the Rho kinase inhibitor Y27632 delays segregation. Cell type-specific inhibition of non-muscle myosin2 activity by overexpression of myosin assembly inhibitor S100A4 reduces tissue surface tension, manifested in decreased compaction during aggregation and inverted geometry observed during segregation. The same is observed when we express a constitutively active Rho kinase isoform to ubiquitously keep actomyosin contractility high at cell-cell and cell-medium interfaces and thus overriding the interface-specific regulation of cortical tensions. Tissue surface tension regulation can become an effective tool in tissue engineering.
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Affiliation(s)
- Elod Méhes
- Department of Biological Physics, ELTE Eötvös University, Budapest, Hungary
| | - Enys Mones
- Department of Biological Physics, ELTE Eötvös University, Budapest, Hungary
| | - Máté Varga
- Department of Genetics, ELTE Eötvös University, Budapest, Hungary
| | - Áron Zsigmond
- Department of Genetics, ELTE Eötvös University, Budapest, Hungary
| | - Beáta Biri-Kovács
- Department of Biochemistry, ELTE Eötvös University, Budapest, Hungary
| | - László Nyitray
- Department of Biochemistry, ELTE Eötvös University, Budapest, Hungary
| | - Vanessa Barone
- Center for Marine Biotechnology and Biomedicine, University of California San Diego, La Jolla, CA, USA
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Gabriel Krens
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Tamás Vicsek
- Department of Biological Physics, ELTE Eötvös University, Budapest, Hungary.
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2
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Abstract
Embryonic cells grow in environments that provide a plethora of physical cues, including mechanical forces that shape the development of the entire embryo. Despite their prevalence, the role of these forces in embryonic development and their integration with chemical signals have been mostly neglected, and scrutiny in modern molecular embryology tilted, instead, towards the dissection of molecular pathways involved in cell fate determination and patterning. It is now possible to investigate how mechanical signals induce downstream genetic regulatory networks to regulate key developmental processes in the embryo. Here, we review the insights into mechanical control of early vertebrate development, including the role of forces in tissue patterning and embryonic axis formation. We also highlight recent in vitro approaches using individual embryonic stem cells and self-organizing multicellular models of human embryos, which have been instrumental in expanding our understanding of how mechanics tune cell fate and cellular rearrangements during human embryonic development.
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3
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Suzuki S, Omori I, Kuraishi R, Kaneko H. Cell sorting and germ layer formation in reconstructed starfish embryos. Dev Growth Differ 2021; 63:343-353. [PMID: 34480340 DOI: 10.1111/dgd.12749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 11/28/2022]
Abstract
Germ layer formation is driven by embryonic cell sorting during the early developmental stages. Starfish (Patiria pectinifera) embryos have a connected endoderm and ectoderm, albeit with few contact surfaces between the epithelia. To better understand the association between cell sorting and germ layer formation, we reconstructed P. pectinifera embryos and examined their germ layer formation. Initial observations showed that the presumptive endodermal (pEN) and presumptive ectodermal (pEC) portions of the embryonic body at the late-blastula stage were preserved throughout development. Based on this, cells that were dissociated from each dermal fragment were mixed in a reconstruction experiment. Our results showed that the pEN and pEC cells were located inside and outside the reaggregates, respectively, to form an embryonic body containing two epithelial layers, separated by a blastocoel. During this process, the pEN cells were motile and shifted from smaller clumps to form a large clump. In contrast, in reaggregates formed in separate cultures, the pEN cells showed strong adhesion abilities, whereas the pEC cells underwent epithelialization. Unlike that in pEN cells, the reaggregation of pEC cells preceded cadherin expression. Filamentous actin was similarly observed in both reaggregates. These results suggest that during the reconstruction of starfish embryos, germ layer formation occurs via the sorting of pEN and pEC cells, depending on their adhesiveness, motility, and epithelialization. In vivo, these properties might embody the physiological significance of cell adhesion in the germ layers constituting the epithelial monolayer.
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Affiliation(s)
- Sohei Suzuki
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama, Japan
| | - Ikuko Omori
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama, Japan.,Department of Hematology, Nippon Medical School, Bunkyo-ku, Japan
| | - Ritsu Kuraishi
- Department of Biology, Research and Education Center for Natural Sciences, Keio University, Yokohama, Japan
| | - Hiroyuki Kaneko
- Department of Biology, Research and Education Center for Natural Sciences, Keio University, Yokohama, Japan
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4
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Minn KT, Fu YC, He S, Dietmann S, George SC, Anastasio MA, Morris SA, Solnica-Krezel L. High-resolution transcriptional and morphogenetic profiling of cells from micropatterned human ESC gastruloid cultures. eLife 2020. [PMID: 33206048 DOI: 10.1101/2020.1101.1122.915777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023] Open
Abstract
During mammalian gastrulation, germ layers arise and are shaped into the body plan while extraembryonic layers sustain the embryo. Human embryonic stem cells, cultured with BMP4 on extracellular matrix micro-discs, reproducibly differentiate into gastruloids, expressing markers of germ layers and extraembryonic cells in radial arrangement. Using single-cell RNA sequencing and cross-species comparisons with mouse, cynomolgus monkey gastrulae, and post-implantation human embryos, we reveal that gastruloids contain cells transcriptionally similar to epiblast, ectoderm, mesoderm, endoderm, primordial germ cells, trophectoderm, and amnion. Upon gastruloid dissociation, single cells reseeded onto micro-discs were motile and aggregated with the same but segregated from distinct cell types. Ectodermal cells segregated from endodermal and extraembryonic but mixed with mesodermal cells. Our work demonstrates that the gastruloid system models primate-specific features of embryogenesis, and that gastruloid cells exhibit evolutionarily conserved sorting behaviors. This work generates a resource for transcriptomes of human extraembryonic and embryonic germ layers differentiated in a stereotyped arrangement.
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Affiliation(s)
- Kyaw Thu Minn
- Department of Biomedical Engineering, Washington University, St. Louis, United States
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Yuheng C Fu
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
- Department of Genetics, Washington University School of Medicine, St. Louis, United States
- Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, United States
| | - Shenghua He
- Department of Computer Science & Engineering, Washington University, St. Louis, United States
| | - Sabine Dietmann
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
- Division of Nephrology, Washington University School of Medicine, St. Louis, United States
- Institute for Informatics, Washington University School of Medicine, St. Louis, United States
| | - Steven C George
- Department of Biomedical Engineering, University of California, Davis, Davis, United States
| | - Mark A Anastasio
- Department of Biomedical Engineering, Washington University, St. Louis, United States
- Department of Bioengineering, University of Illinois, Urbana-Champaign, United States
| | - Samantha A Morris
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
- Department of Genetics, Washington University School of Medicine, St. Louis, United States
- Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, United States
| | - Lilianna Solnica-Krezel
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
- Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, United States
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5
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Minn KT, Fu YC, He S, Dietmann S, George SC, Anastasio MA, Morris SA, Solnica-Krezel L. High-resolution transcriptional and morphogenetic profiling of cells from micropatterned human ESC gastruloid cultures. eLife 2020; 9:e59445. [PMID: 33206048 PMCID: PMC7728446 DOI: 10.7554/elife.59445] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 11/17/2020] [Indexed: 12/29/2022] Open
Abstract
During mammalian gastrulation, germ layers arise and are shaped into the body plan while extraembryonic layers sustain the embryo. Human embryonic stem cells, cultured with BMP4 on extracellular matrix micro-discs, reproducibly differentiate into gastruloids, expressing markers of germ layers and extraembryonic cells in radial arrangement. Using single-cell RNA sequencing and cross-species comparisons with mouse, cynomolgus monkey gastrulae, and post-implantation human embryos, we reveal that gastruloids contain cells transcriptionally similar to epiblast, ectoderm, mesoderm, endoderm, primordial germ cells, trophectoderm, and amnion. Upon gastruloid dissociation, single cells reseeded onto micro-discs were motile and aggregated with the same but segregated from distinct cell types. Ectodermal cells segregated from endodermal and extraembryonic but mixed with mesodermal cells. Our work demonstrates that the gastruloid system models primate-specific features of embryogenesis, and that gastruloid cells exhibit evolutionarily conserved sorting behaviors. This work generates a resource for transcriptomes of human extraembryonic and embryonic germ layers differentiated in a stereotyped arrangement.
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Affiliation(s)
- Kyaw Thu Minn
- Department of Biomedical Engineering, Washington UniversitySt. LouisUnited States
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
| | - Yuheng C Fu
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
- Center of Regenerative Medicine, Washington University School of MedicineSt. LouisUnited States
| | - Shenghua He
- Department of Computer Science & Engineering, Washington UniversitySt. LouisUnited States
| | - Sabine Dietmann
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Division of Nephrology, Washington University School of MedicineSt. LouisUnited States
- Institute for Informatics, Washington University School of MedicineSt. LouisUnited States
| | - Steven C George
- Department of Biomedical Engineering, University of California, DavisDavisUnited States
| | - Mark A Anastasio
- Department of Biomedical Engineering, Washington UniversitySt. LouisUnited States
- Department of Bioengineering, University of IllinoisUrbana-ChampaignUnited States
| | - Samantha A Morris
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
- Center of Regenerative Medicine, Washington University School of MedicineSt. LouisUnited States
| | - Lilianna Solnica-Krezel
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Center of Regenerative Medicine, Washington University School of MedicineSt. LouisUnited States
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6
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Fagotto F. Tissue segregation in the early vertebrate embryo. Semin Cell Dev Biol 2020; 107:130-146. [DOI: 10.1016/j.semcdb.2020.05.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 11/30/2022]
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7
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Banote RK, Chebli J, Şatır TM, Varshney GK, Camacho R, Ledin J, Burgess SM, Abramsson A, Zetterberg H. Amyloid precursor protein-b facilitates cell adhesion during early development in zebrafish. Sci Rep 2020; 10:10127. [PMID: 32576936 PMCID: PMC7311384 DOI: 10.1038/s41598-020-66584-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 05/21/2020] [Indexed: 01/05/2023] Open
Abstract
Understanding the biological function of amyloid beta (Aβ) precursor protein (APP) beyond its role in Alzheimer's disease is emerging. Yet, its function during embryonic development is poorly understood. The zebrafish APP orthologue, Appb, is strongly expressed during early development but thus far has only been studied via morpholino-mediated knockdown. Zebrafish enables analysis of cellular processes in an ontogenic context, which is limited in many other vertebrates. We characterized zebrafish carrying a homozygous mutation that introduces a premature stop in exon 2 of the appb gene. We report that appb mutants are significantly smaller until 2 dpf and display perturbed enveloping layer (EVL) integrity and cell protrusions at the blastula stage. Moreover, appb mutants surviving beyond 48 hpf exhibited no behavioral defects at 6 dpf and developed into healthy and fertile adults. The expression of the app family member, appa, was also found to be altered in appb mutants. Taken together, we show that appb is involved in the initial development of zebrafish by supporting the integrity of the EVL, likely by mediating cell adhesion properties. The loss of Appb might then be compensated for by other app family members to maintain normal development.
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Affiliation(s)
- Rakesh Kumar Banote
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, S-41345, Gothenburg, Sweden.,Cellectricon AB, Neongatan 4B, SE-431 53, Mölndal, Sweden
| | - Jasmine Chebli
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, S-41345, Gothenburg, Sweden
| | - Tuğçe Munise Şatır
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, S-41345, Gothenburg, Sweden
| | - Gaurav K Varshney
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA.,Genes & Human Disease Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Rafael Camacho
- Centre for Cellular Imaging, Core Facilities, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Johan Ledin
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA.,Department of Organismal Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Shawn M Burgess
- Translational and Functional Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Alexandra Abramsson
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, S-41345, Gothenburg, Sweden.
| | - Henrik Zetterberg
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, S-41345, Gothenburg, Sweden.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N3BG, United Kingdom.,UK Dementia Research Institute, London, WC1N3BG, United Kingdom
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8
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Abdel Fattah AR, Ranga A. Nanoparticles as Versatile Tools for Mechanotransduction in Tissues and Organoids. Front Bioeng Biotechnol 2020; 8:240. [PMID: 32363177 PMCID: PMC7180186 DOI: 10.3389/fbioe.2020.00240] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/09/2020] [Indexed: 12/28/2022] Open
Abstract
Organoids are 3D multicellular constructs that rely on self-organized cell differentiation, patterning and morphogenesis to recapitulate key features of the form and function of tissues and organs of interest. Dynamic changes in these systems are orchestrated by biochemical and mechanical microenvironments, which can be engineered and manipulated to probe their role in developmental and disease mechanisms. In particular, the in vitro investigation of mechanical cues has been the focus of recent research, where mechanical manipulations imparting local as well as large-scale mechanical stresses aim to mimic in vivo tissue deformations which occur through proliferation, folding, invagination, and elongation. However, current in vitro approaches largely impose homogeneous mechanical changes via a host matrix and lack the required positional and directional specificity to mimic the diversity of in vivo scenarios. Thus, while organoids exhibit limited aspects of in vivo morphogenetic events, how local forces are coordinated to enable large-scale changes in tissue architecture remains a difficult question to address using current techniques. Nanoparticles, through their efficient internalization by cells and dispersion through extracellular matrices, have the ability to provide local or global, as well as passive or active modulation of mechanical stresses on organoids and tissues. In this review, we explore how nanoparticles can be used to manipulate matrix and tissue mechanics, and highlight their potential as tools for fate regulation through mechanotransduction in multicellular model systems.
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Affiliation(s)
- Abdel Rahman Abdel Fattah
- Laboratory of Bioengineering and Morphogenesis, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Adrian Ranga
- Laboratory of Bioengineering and Morphogenesis, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
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9
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Abstract
ABSTRACT
Cell–cell adhesion strength, measured as tissue surface tension, spans an enormous 1000-fold range when different cell types are compared. However, the examination of basic mechanical principles of cell adhesion indicates that cadherin-based and related mechanisms are not able to promote the high-strength adhesion experimentally observed in many late embryonic or malignant tissues. Therefore, the hypothesis is explored that the interaction of the pericellular matrices of cells generates strong adhesion by a mechanism akin to the self-adhesion/self-healing of dynamically cross-linked hydrogels. Quantitative data from biofilm matrices support this model. The mechanism links tissue surface tension to pericellular matrix stiffness. Moreover, it explains the wide, matrix-filled spaces around cells in liquid-like, yet highly cohesive, tissues, and it rehabilitates aspects of the original interpretation of classical cell sorting experiments, as expressed in Steinberg's differential adhesion hypothesis: that quantitative differences in adhesion energies between cells are sufficient to drive sorting.
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Affiliation(s)
- Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada
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10
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Yu M, Mahtabfar A, Beelen P, Demiryurek Y, Shreiber DI, Zahn JD, Foty RA, Liu L, Lin H. Coherent Timescales and Mechanical Structure of Multicellular Aggregates. Biophys J 2019; 114:2703-2716. [PMID: 29874619 DOI: 10.1016/j.bpj.2018.04.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/29/2018] [Accepted: 04/09/2018] [Indexed: 02/06/2023] Open
Abstract
Multicellular aggregates are an excellent model system to explore the role of tissue biomechanics in specifying multicellular reorganization during embryonic developments and malignant invasion. Tissue-like spheroids, when subjected to a compressive force, are known to exhibit liquid-like behaviors at long timescales (hours), largely because of cell rearrangements that serve to effectively dissipate the applied stress. At short timescales (seconds to minutes), before cell rearrangement, the mechanical behavior is strikingly different. The current work uses shape relaxation to investigate the structural characteristics of aggregates and discovers two coherent timescales: one on the order of seconds, the other tens of seconds. These timescales are universal, conserved across a variety of tested species, and persist despite great differences in other properties such as tissue surface tension and adhesion. A precise mathematical theory is used to correlate the timescales with mechanical properties and reveals that aggregates have a relatively strong envelope and an unusually "soft" interior (weak bulk elastic modulus). This characteristic is peculiar, considering that both layers consist of identical units (cells), but is consistent with the fact that this structure can engender both structural integrity and the flexibility required for remodeling. In addition, tissue surface tension, elastic modulus, and viscosity are proportional to each other. Considering that these tissue-level properties intrinsically derive from cellular-level properties, the proportionalities imply precise coregulation of the latter and in particular of the tension on the cell-medium and cell-cell interfaces.
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Affiliation(s)
- Miao Yu
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Aria Mahtabfar
- Department of Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Paul Beelen
- Department of Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Yasir Demiryurek
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - David I Shreiber
- Department of Biomedical Engineering, The State University of New Jersey, Piscataway, New Jersey
| | - Jeffrey D Zahn
- Department of Biomedical Engineering, The State University of New Jersey, Piscataway, New Jersey
| | - Ramsey A Foty
- Department of Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| | - Liping Liu
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey; Department of Mathematics, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Hao Lin
- Department of Mechanical and Aerospace Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey.
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11
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Abstract
Mechanical forces are an important contributor to cell fate specification and cell migration during embryonic development in animals. Similarities between embryogenesis and regeneration, particularly with regards to pattern formation and large-scale tissue movements, suggest similarly important roles for physical forces during regeneration. While the influence of the mechanical environment on stem cell differentiation in vitro is being actively exploited in the fields of tissue engineering and regenerative medicine, comparatively little is known about the role of stresses and strains acting during animal regeneration. In this review, we summarize published work on the role of physical principles and mechanical forces in animal regeneration. Novel experimental techniques aimed at addressing the role of mechanics in embryogenesis have greatly enhanced our understanding at scales from the subcellular to the macroscopic - we believe the time is ripe for the field of regeneration to similarly leverage the tools of the mechanobiological research community.
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Affiliation(s)
- Kevin Chiou
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eva-Maria S Collins
- Physics Department, UC San Diego, La Jolla, CA 92093, USA; Section of Cell&Developmental Biology, UC San Diego, La Jolla, CA 92093, USA.
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12
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Abstract
Colloidal gels are three-dimensional networks of microgel particles and can be utilized to design microtissues where the differential adhesive interactions between the particles and cells, guided by their surface energetics, are engineered to spatially assemble the cellular and colloidal components into three-dimensional microtissues. In this work we utilized a colloidal interaction approach to design cell-polyurethane (PU) microgel bimodal microtissues using endothelial cells (ECs) as a normal cell model and a nonmalignant breast cancer cell line (MCF-7) as a cancer cell model. PU microgels were developed from a library of segmental polyurethanes with poly(ethylene glycol) soft segment and aliphatic diisocyanate/l-tyrosine based chain extender as hard segment to modulate the interactions between PU colloidal particles and cells. The surface energies of the microgel particles and cells were estimated using Zisman's critical surface tension and van Oss-Good-Chaudhury theory (vOGCT) from liquid contact angle analysis. Binary interaction potentials between colloidal PU particles and cells and the ternary interaction between colloidal PU particle, cell, and collagen I/Matrigel were calculated to explain the formation of microtissues and their spreading in extraneous biomatrix respectively by using classical and extended DLVO theory (XDLVO). Furthermore, rheological analysis and in silico simulations were used to analyze the assembly and spreading of the PU microgel based microtissues. In vitro experiments showed that ECs and MCF-7 displayed more differentiated (EC spreading/MCF-7 lumen formation) character when mixed with microgel particles that were stable in aqueous medium and more undifferentiated character (EC nonspreading/MCF-7 spreading) when mixed with microgel particles unstable in aqueous medium.
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Affiliation(s)
- Michael J. Hill
- Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Debanjan Sarkar
- Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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13
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Winklbauer R, Parent SE. Forces driving cell sorting in the amphibian embryo. Mech Dev 2017; 144:81-91. [DOI: 10.1016/j.mod.2016.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/18/2016] [Accepted: 09/29/2016] [Indexed: 01/05/2023]
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14
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Abstract
Cells have an intrinsic ability to self-assemble and self-organize into complex and functional tissues and organs. By taking advantage of this ability, embryoids, organoids and gastruloids have recently been generated in vitro, providing a unique opportunity to explore complex embryological events in a detailed and highly quantitative manner. Here, we examine how such approaches are being used to answer fundamental questions in embryology, such as how cells self-organize and assemble, how the embryo breaks symmetry, and what controls timing and size in development. We also highlight how further improvements to these exciting technologies, based on the development of quantitative platforms to precisely follow and measure subcellular and molecular events, are paving the way for a more complete understanding of the complex events that help build the human embryo.
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Affiliation(s)
- Mijo Simunovic
- Center for Studies in Physics and Biology, The Rockefeller University, New York, NY 10065, USA
- Laboratory of Stem Cell Biology and Molecular Embryology, The Rockefeller University, New York, NY 10065, USA
| | - Ali H Brivanlou
- Laboratory of Stem Cell Biology and Molecular Embryology, The Rockefeller University, New York, NY 10065, USA
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15
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Abstract
Morphogenetic mechanisms such as cell movement or tissue separation depend on cell attachment and detachment processes, which involve adhesion receptors as well as the cortical cytoskeleton. The interplay between the two components is of stunning complexity. Most strikingly, the binding energy of adhesion molecules is usually too small for substantial cell-cell attachment, pointing to a main deficit in our present understanding of adhesion. In this Opinion article, I integrate recent findings and conceptual advances in the field into a coherent framework for cell adhesion. I argue that active cortical tension is best viewed as an integral part of adhesion, and propose on this basis a non-arbitrary measure of adhesion strength - the tissue surface tension of cell aggregates. This concept of adhesion integrates heterogeneous molecular inputs into a single mechanical property and simplifies the analysis of attachment-detachment processes. It draws attention to the enormous variation of adhesion strengths among tissues, whose origin and function is little understood.
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Affiliation(s)
- Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada
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16
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Abstract
Mechanical interactions are essential for bending and shaping tissues during morphogenesis. A common feature of nearly all internal organs is the formation of a tubular network consisting of an epithelium that surrounds a central lumen. Lumen formation during organogenesis requires precisely coordinated mechanical and biochemical interactions. Whereas many genetic regulators of lumen formation have been identified, relatively little is known about the mechanical cues that drive lumen morphogenesis. Lumens can be shaped by a variety of physical behaviors including wrapping a sheet of cells around a hollow core, rearranging cells to expose a lumenal cavity, or elongating a tube via cell migration, though many of the details underlying these movements remain poorly understood. It is essential to define how forces generated by individual cells cooperate to produce the tissue-level forces that drive organogenesis. Transduction of mechanical forces relies on several conserved processes including the contraction of cytoskeletal networks or expansion of lumens through increased fluid pressure. The morphogenetic events that drive lumen formation serve as a model for similar mechanical processes occurring throughout development. To understand how lumenal networks arise, it will be essential to investigate how biochemical and mechanical processes integrate to generate complex structures from comparatively simple interactions.
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Affiliation(s)
- Adam Navis
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, United States
| | - Celeste M Nelson
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, United States; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States.
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Asthana A, Kisaalita WS. Molecular basis for cytokine biomarkers of complex 3D microtissue physiology in vitro. Drug Discov Today 2016; 21:950-61. [PMID: 27021792 DOI: 10.1016/j.drudis.2016.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 02/05/2016] [Accepted: 03/16/2016] [Indexed: 11/24/2022]
Abstract
'Physiologically more-relevant' claims are readily made for cells cultured on any surface or in a scaffold that provides loosely defined 3D geometry. A set of tools to measure culture '3D-ness' more accurately are needed. Such tools should find applications in fields ranging from high-throughput identification of substrates for tissue engineering and regenerative medicine to cell-based screening of drug candidates. Until now, these fields have not provided a consensus for the most promising place to initiate the search. Here, we review recent advances in transcriptomic, proteomic, inflammation and oncology-related pathways, as well as functional studies that strongly point to cytokines as the most likely compounds to form the missing consensus.
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Abstract
During embryonic development, tissues deform by a succession and combination of morphogenetic processes. Tissue compaction is the morphogenetic process by which a tissue adopts a tighter structure. Recent studies characterized the respective roles of cells' adhesive and contractile properties in tissue compaction. In this review, we formalize the mechanical and molecular principles of tissue compaction and we analyze through the prism of this framework several morphogenetic events: the compaction of the early mouse embryo, the formation of the fly retina, the segmentation of somites and the separation of germ layers during gastrulation.
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Affiliation(s)
- Hervé Turlier
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Jean-Léon Maître
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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Abstract
In development, cells organize into biological tissues through cell growth, migration, and differentiation. Globally, this process is dictated by a genetically encoded program in which secreted morphogens and cell-cell interactions prompt the adoption of unique cell fates. Yet, at its lowest level, development is achieved through the modification of cell-cell adhesion and actomyosin-based contractility, which set the level of tension within cells and dictate how they pack together into tissues. The regulation of tension within individual cells and across large groups of cells is a major driving force of tissue organization and the basis of all cell shape change and cell movement in development.
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Affiliation(s)
- Evan Heller
- Howard Hughes Medical Institute, Robin Neustein Chemers Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065
| | - Elaine Fuchs
- Howard Hughes Medical Institute, Robin Neustein Chemers Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065
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Fathi-Azarbayjani A, Jouyban A. Surface tension in human pathophysiology and its application as a medical diagnostic tool. ACTA ACUST UNITED AC 2015; 5:29-44. [PMID: 25901295 PMCID: PMC4401165 DOI: 10.15171/bi.2015.06] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 01/03/2015] [Accepted: 01/26/2015] [Indexed: 12/29/2022]
Abstract
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Introduction: Pathological features of disease appear to be quite different. Despite this diversity, the common feature of various disorders underlies physicochemical and biochemical factors such as surface tension. Human biological fluids comprise various proteins and phospholipids which are capable of adsorption at fluid interfaces and play a vital role in the physiological function of human organs. Surface tension of body fluids correlates directly to the development of pathological states.
Methods: In this review, the variety of human diseases mediated by the surface tension changes of biological phenomena and the failure of biological fluids to remain in their native state are discussed.
Results: Dynamic surface tension measurements of human biological fluids depend on various parameters such as sex, age and changes during pregnancy or certain disease. It is expected that studies of surface tension behavior of human biological fluids will provide additional information and might become useful in medical practice. Theoretical background on surface tension measurement and surface tension values of reference fluids obtained from healthy and sick patients are depicted.
Conclusion: It is well accepted that no single biomarker will be effective in clinical diagnosis. The surface tension measurement combined with routine lab tests may be a novel non-invasive method which can not only facilitate the discovery of diagnostic models for various diseases and its severity, but also be a useful tool for monitoring treatment efficacy. We therefore expect that studies of surface tension behavior of human biological fluids will provide additional useful information in medical practice.
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Affiliation(s)
| | - Abolghasem Jouyban
- Drug Applied Research Center and Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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Abstract
Morphogenetic processes often involve the rapid rearrangement of cells held together by mutual adhesion. The dynamic nature of this adhesion endows tissues with liquid-like properties, such that large-scale shape changes appear as tissue flows. Generally, the resistance to flow (tissue viscosity) is expected to depend on the cohesion of a tissue (how strongly its cells adhere to each other), but the exact relationship between these parameters is not known. Here, we analyse the link between cohesion and viscosity to uncover basic mechanical principles of cell rearrangement. We show that for vertebrate and invertebrate tissues, viscosity varies in proportion to cohesion over a 200-fold range of values. We demonstrate that this proportionality is predicted by a cell-based model of tissue viscosity. To do so, we analyse cell adhesion in Xenopus embryonic tissues and determine a number of parameters, including tissue surface tension (as a measure of cohesion), cell contact fluctuation and cortical tension. In the tissues studied, the ratio of surface tension to viscosity, which has the dimension of a velocity, is 1.8 µm/min. This characteristic velocity reflects the rate of cell-cell boundary contraction during rearrangement, and sets a limit to rearrangement rates. Moreover, we propose that, in these tissues, cell movement is maximally efficient. Our approach to cell rearrangement mechanics links adhesion to the resistance of a tissue to plastic deformation, identifies the characteristic velocity of the process, and provides a basis for the comparison of tissues with mechanical properties that may vary by orders of magnitude.
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Affiliation(s)
- Robert David
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
| | - Olivia Luu
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
| | - Erich W Damm
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
| | - Jason W H Wen
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
| | - Martina Nagel
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
| | - Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, Canada M5S 3G5
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Abstract
Patients with glioblastoma typically present when tumors are at an advanced stage. Surgical resection, radiotherapy and adjuvant chemotherapy are currently the standard of care for glioblastoma. However, due to the infiltrative and dispersive nature of the tumor, recurrence rate remains high and typically results in very poor prognosis. Efforts to treat the primary tumor are, therefore, palliative rather than curative. From a practical perspective, controlling growth and dispersal of the recurrence may have a greater impact on disease-free survival. In order for cells to disperse, they must first detach from the mass. Preventing detachment may keep tumors that recur more localized and perhaps more amenable to therapy. Here we introduce a new perspective in which a quantifiable mechanical property, namely tissue surface tension, can provide novel information on tumor behavior. The overall theme of the discussion will attempt to integrate how adhesion molecules can alter a tumor's mechanical properties and how, in turn, these properties can be modified to prevent tumor cell detachment and dispersal.
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Affiliation(s)
- Ramsey A Foty
- Department of Surgery, University of Medicine & Dentistry, New Jersey Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA.
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Harata A, Matsuzaki T, Nishikawa A, Ihara S. The cell sorting process of Xenopus gastrula cells involves the acto-myosin system and TGF-β signaling. In Vitro Cell Dev Biol Anim 2013; 49:220-9. [PMID: 23435857 DOI: 10.1007/s11626-013-9586-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 01/25/2013] [Indexed: 01/03/2023]
Abstract
We have previously shown that the cell sorting process of animal pole cells (AC) and vegetal pole cells (VC) from Xenopus gastrulae is considered to involve two steps: concentrification and polarization. In this study, we addressed the question of what specified the spatial relationship of the AC and VC clusters during the process. First, we examined the inhibitory or facilitatory treatment for myosin 2 activity during each of the two steps. The aggregates treated with Y27632 or blebbistatin during the concentrification step showed a cluster random arrangement, suggesting the prevention of the cell sorting by inhibition of myosin 2. Meanwhile, the treatment with a Rac1 inhibitor, NSC23766, during the same step resulted in promotion of the fusion of the AC clusters and the progression of the cell sorting, presumably by an indirect activation of myosin 2. On the other hand, the treatments with any of the three drugs during the polarization step showed that the two clusters did not appose, and their array remained concentric. Thus, the modulation of cell contraction might be indispensable to each of the two steps. Next, the activin/nodal TGF-β signaling was perturbed by using a specific activin receptor-like kinase inhibitor, SB431542. The results revealed a bimodal participation of the activin/nodal TGF-β signaling, i.e., suppressive and promotive effects on the concentrification and the polarization, respectively. Thus, the present in vitro system, which permits not only the cell contraction-mediated cell sorting but also the TGF-β-directed mesodermal induction such as cartilage formation, may fairly reflect the embryogenesis in vivo.
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Affiliation(s)
- Ayano Harata
- Department of Biological Science, Faculty of Life and Environmental Science, Shimane University, 1060 Nisikawatsu-cho, Matsue, Shimane, 690-8504, Japan
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Harata A, Matsuzaki T, Ozaki K, Ihara S. The Cell Sorting Process of Xenopus Gastrula Cells Progresses in a Stepwise Fashion Involving Concentrification and Polarization. Cell 2013. [DOI: 10.4236/cellbio.2013.22007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Barone V, Heisenberg CP. Cell adhesion in embryo morphogenesis. Curr Opin Cell Biol 2012; 24:148-53. [DOI: 10.1016/j.ceb.2011.11.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/08/2011] [Accepted: 11/16/2011] [Indexed: 01/11/2023]
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Abstract
Xenopus gastrulation consists of the orderly deformation of a single, multilayered cell sheet that resembles a multilayered epithelium, and flexible cell-cell adhesion has to provide tissue cohesion while allowing for cell rearrangements that drive gastrulation. A few classic cadherins are expressed in the Xenopus early embryo. The prominent C-cadherin is essential for the cohesion of the animal part of the gastrula including ectoderm and chordamesoderm, and it contributes to the adhesion of endoderm and anterior mesoderm in the vegetal moiety. The cadherin/catenin complex is expressed in a graded pattern which is stable during early development. Regional differences in cell adhesion conform to the graded cadherin/catenin expression pattern. However, although the cadherin/catenin pattern seems to be actively maintained, and cadherin function is modulated to reinforce differential adhesiveness, it is not clear how regional differences in tissue cohesion affect gastrulation. Manipulating cadherin expression or function does not induce cell sorting or boundary formation in the embryo. Moreover, known boundary formation mechanisms in the gastrula are based on active cell repulsion. Cell rearrangement is also compatible with variable tissue cohesion. Thus, identifying roles for differential adhesion in the Xenopus gastrula remains a challenge.
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Affiliation(s)
- Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada,
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29
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Blancas AA, Chen CS, Stolberg S, McCloskey KE. Adhesive forces in embryonic stem cell cultures. Cell Adh Migr 2011; 5:472-9. [PMID: 22274712 PMCID: PMC3277780 DOI: 10.4161/cam.5.6.18270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 09/21/2011] [Accepted: 09/30/2011] [Indexed: 12/19/2022] Open
Abstract
Most cell culture systems grow and spread as contact-inhibited monolayers on flat culture dishes, but the embryonic stem cell (ESC) is one of the cell phenotypes that prefer to self-organize as tightly packed three-dimensional (3D) colonies. ESC also readily form 3D cell aggregates, called embryoid bodies (EB) that partially mimic the spatial and temporal processes of the developing embryo. Here, the rationale for ESC aggregatation, rather than "spreading" on gelatin-coated or mouse embryonic fibroblast (MEF)-coated dishes, is examined through the quantification of the expression levels of adhesion molecules on ESC and the calculation of the adhesive forces on ESC. Modeling each ESC as a dodecahedron, the adhesive force for each ESC-ESC binding was found to be 9.1 x 10(5) pN, whereas, the adhesive force for ESC-MEF binding was found to be an order of magnitude smaller at 7.9 x 10(4) pN. We also show that E-cadherin is the dominating molecule in the ESC-ESC adhesion and blocking E-cadherin leads to a significant reduction in colony formation. Here, we mathematically describe the preference for ESC to self-assemble into ESC-ESC aggregates and 3D colonies, rather than to bind and spread on gelatin or MEF-coated dishes, and have shown that these interactions are predominantly due to E-cadherin expression on ESC.
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Affiliation(s)
- Alicia A Blancas
- Graduate Program in Quantitative and Systems Biology, University of California Merced, Merced, CA, USA
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30
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Abstract
Morphogenesis takes place against a background of organism-to-organism and environmental variation. Therefore, fundamental questions in the study of morphogenesis include: How are the mechanical processes of tissue movement and deformation affected by that variability, and in turn, how do the mechanic of the system modulate phenotypic variation? We highlight a few key factors, including environmental temperature, embryo size and environmental chemistry that might perturb the mechanics of morphogenesis in natural populations. Then we discuss several ways in which mechanics-including feedback from mechanical cues-might influence intra-specific variation in morphogenesis. To understand morphogenesis it will be necessary to consider whole-organism, environment and evolutionary scales because these larger scales present the challenges that developmental mechanisms have evolved to cope with. Studying the variation organisms express and the variation organisms experience will aid in deciphering the causes of birth defects.
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Affiliation(s)
- Michelangelo von Dassow
- Department of Bioengineering, University of Pittsburgh, 3501 Fifth Ave, 5059-BST3, Pittsburgh, PA 15213, USA.
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31
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Abstract
Studies of cell-cell cohesion and cell-substratum adhesion have historically been performed on monolayer cultures adherent to rigid substrates. Cells within a tissue, however, are typically encased within a closely packed tissue mass in which cells establish intimate connections with many near-neighbors and with extracellular matrix components. Accordingly, the chemical milieu and physical forces experienced by cells within a 3D tissue are fundamentally different than those experienced by cells grown in monolayer culture. This has been shown to markedly impact cellular morphology and signaling. Several methods have been devised to generate 3D cell cultures including encapsulation of cells in collagen gels or in biomaterial scaffolds. Such methods, while useful, do not recapitulate the intimate direct cell-cell adhesion architecture found in normal tissues. Rather, they more closely approximate culture systems in which single cells are loosely dispersed within a 3D meshwork of ECM products. Here, we describe a simple method in which cells are placed in hanging drop culture and incubated under physiological conditions until they form true 3D spheroids in which cells are in direct contact with each other and with extracellular matrix components. The method requires no specialized equipment and can be adapted to include addition of any biological agent in very small quantities that may be of interest in elucidating effects on cell-cell or cell-ECM interaction. The method can also be used to co-culture two (or more) different cell populations so as to elucidate the role of cell-cell or cell-ECM interactions in specifying spatial relationships between cells. Cell-cell cohesion and cell-ECM adhesion are the cornerstones of studies of embryonic development, tumor-stromal cell interaction in malignant invasion, wound healing, and for applications to tissue engineering. This simple method will provide a means of generating tissue-like cellular aggregates for measurement of biomechanical properties or for molecular and biochemical analysis in a physiologically relevant model.
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Affiliation(s)
- Ramsey Foty
- Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, USA.
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Rohani N, Canty L, Luu O, Fagotto F, Winklbauer R. EphrinB/EphB signaling controls embryonic germ layer separation by contact-induced cell detachment. PLoS Biol 2011; 9:e1000597. [PMID: 21390298 PMCID: PMC3046958 DOI: 10.1371/journal.pbio.1000597] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Accepted: 01/18/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The primordial organization of the metazoan body is achieved during gastrulation by the establishment of the germ layers. Adhesion differences between ectoderm, mesoderm, and endoderm cells could in principle be sufficient to maintain germ layer integrity and prevent intermixing. However, in organisms as diverse as fly, fish, or amphibian, the ectoderm-mesoderm boundary not only keeps these germ layers separated, but the ectoderm also serves as substratum for mesoderm migration, and the boundary must be compatible with repeated cell attachment and detachment. PRINCIPAL FINDINGS We show that localized detachment resulting from contact-induced signals at the boundary is at the core of ectoderm-mesoderm segregation. Cells alternate between adhesion and detachment, and detachment requires ephrinB/EphB signaling. Multiple ephrinB ligands and EphB receptors are expressed on each side of the boundary, and tissue separation depends on forward signaling across the boundary in both directions, involving partially redundant ligands and receptors and activation of Rac and RhoA. CONCLUSION This mechanism differs from a simple differential adhesion process of germ layer formation. Instead, it involves localized responses to signals exchanged at the tissue boundary and an attachment/detachment cycle which allows for cell migration across a cellular substratum.
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Affiliation(s)
- Nazanin Rohani
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Laura Canty
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Olivia Luu
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - François Fagotto
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
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Abstract
During the development of multicellular organisms, cell fate specification is followed by the sorting of different cell types into distinct domains from where the different tissues and organs are formed. Cell sorting involves both the segregation of a mixed population of cells with different fates and properties into distinct domains, and the active maintenance of their segregated state. Because of its biological importance and apparent resemblance to fluid segregation in physics, cell sorting was extensively studied by both biologists and physicists over the last decades. Different theories were developed that try to explain cell sorting on the basis of the physical properties of the constituent cells. However, only recently the molecular and cellular mechanisms that control the physical properties driving cell sorting, have begun to be unraveled. In this review, we will provide an overview of different cell-sorting processes in development and discuss how these processes can be explained by the different sorting theories, and how these theories in turn can be connected to the molecular and cellular mechanisms driving these processes.
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Affiliation(s)
- S F Gabby Krens
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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Caicedo-Carvajal CE, Shinbrot T, Foty RA. Alpha5beta1 integrin-fibronectin interactions specify liquid to solid phase transition of 3D cellular aggregates. PLoS One 2010; 5:e11830. [PMID: 20686611 PMCID: PMC2912296 DOI: 10.1371/journal.pone.0011830] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 06/30/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Tissue organization during embryonic development and wound healing depends on the ability of cells on the one hand to exchange adhesive bonds during active rearrangement and on the other to become fixed in place as tissue homeostasis is reached. Cells achieve these contradictory tasks by regulating either cell-cell adhesive bonds, mediated by cadherins, or cell-extracellular matrix (ECM) connections, regulated by integrins. Integrin alpha5beta1 and soluble fibronectin (sFN) are key players in cell-ECM force generation and in ECM polymerization. Here, we explore the interplay between integrin alpha5beta1 and sFN and its influence on tissue mechanical properties and cell sorting behavior. METHODOLOGY/PRINCIPAL FINDINGS We generated a series of cell lines varying in alpha5beta1 receptor density. We then systematically explored the effects of different sFN concentrations on aggregate biomechanical properties using tissue surface tensiometry. We found previously unreported complex behaviors including the observation that interactions between fibronectin and integrin alpha5beta1 generates biphasic tissue cohesion profiles. Specifically, we show that at constant sFn concentration, aggregate cohesion increases linearly as alpha5beta1 receptor density is increased from low to moderate levels, producing a transition from viscoelastic-liquid to pseudo viscoelastic-solid behavior. However, further increase in receptor density causes an abrupt drop in tissue cohesion and a transition back to viscoelastic-liquid properties. We propose that this may be due to depletion of sFn below a critical value in the aggregate microenvironment at high alpha5beta1 levels. We also show that differential expression of alpha5beta1 integrin can promote phase-separation between cells. CONCLUSIONS/SIGNIFICANCE The interplay between alpha5-integrin and sFn contributes significantly to tissue cohesion and, depending on their level of expression, can mediate a shift from liquid to elastic behavior. This interplay represents a tunable level of control between integrins and the ECM that can influence tissue cohesion and other mechanical properties, which may translate to the specification of tissue structure and function. These studies provide insights into important biological processes such as embryonic development, wound healing, and for tissue engineering applications.
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Affiliation(s)
- Carlos E. Caicedo-Carvajal
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey, United States of America
| | - Troy Shinbrot
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey, United States of America
| | - Ramsey A. Foty
- Department of Surgery, University of Medicine and Dentistry, New Jersey-Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States of America
- * E-mail:
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Manning ML, Foty RA, Steinberg MS, Schoetz EM. Coaction of intercellular adhesion and cortical tension specifies tissue surface tension. Proc Natl Acad Sci U S A 2010; 107:12517-22. [PMID: 20616053 DOI: 10.1073/pnas.1003743107] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In the course of animal morphogenesis, large-scale cell movements occur, which involve the rearrangement, mutual spreading, and compartmentalization of cell populations in specific configurations. Morphogenetic cell rearrangements such as cell sorting and mutual tissue spreading have been compared with the behaviors of immiscible liquids, which they closely resemble. Based on this similarity, it has been proposed that tissues behave as liquids and possess a characteristic surface tension, which arises as a collective, macroscopic property of groups of mobile, cohering cells. But how are tissue surface tensions generated? Different theories have been proposed to explain how mesoscopic cell properties such as cell-cell adhesion and contractility of cell interfaces may underlie tissue surface tensions. Although recent work suggests that both may be contributors, an explicit model for the dependence of tissue surface tension on these mesoscopic parameters has been missing. Here we show explicitly that the ratio of adhesion to cortical tension determines tissue surface tension. Our minimal model successfully explains the available experimental data and makes predictions, based on the feedback between mechanical energy and geometry, about the shapes of aggregate surface cells, which we verify experimentally. This model indicates that there is a crossover from adhesion dominated to cortical-tension dominated behavior as a function of the ratio between these two quantities.
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Visconti RP, Kasyanov V, Gentile C, Zhang J, Markwald RR, Mironov V. Towards organ printing: engineering an intra-organ branched vascular tree. Expert Opin Biol Ther 2010; 10:409-20. [PMID: 20132061 DOI: 10.1517/14712590903563352] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
IMPORTANCE OF THE FIELD Effective vascularization of thick three-dimensional engineered tissue constructs is a problem in tissue engineering. As in native organs, a tissue-engineered intra-organ vascular tree must be comprised of a network of hierarchically branched vascular segments. Despite this requirement, current tissue-engineering efforts are still focused predominantly on engineering either large-diameter macrovessels or microvascular networks. AREAS COVERED IN THIS REVIEW We present the emerging concept of organ printing or robotic additive biofabrication of an intra-organ branched vascular tree, based on the ability of vascular tissue spheroids to undergo self-assembly. WHAT THE READER WILL GAIN The feasibility and challenges of this robotic biofabrication approach to intra-organ vascularization for tissue engineering based on organ-printing technology using self-assembling vascular tissue spheroids including clinically relevantly vascular cell sources are analyzed. TAKE HOME MESSAGE It is not possible to engineer 3D thick tissue or organ constructs without effective vascularization. An effective intra-organ vascular system cannot be built by the simple connection of large-diameter vessels and microvessels. Successful engineering of functional human organs suitable for surgical implantation will require concomitant engineering of a 'built in' intra-organ branched vascular system. Organ printing enables biofabrication of human organ constructs with a 'built in' intra-organ branched vascular tree.
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Affiliation(s)
- Richard P Visconti
- Medical University of South Carolina, Bioprinting Research Center, Department of Regenerative Medicine and Cell Biology, 173 Ashley Avenue, Charleston, SC 29425, USA
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Brodland GW, Yang J, Sweny J. Cellular interfacial and surface tensions determined from aggregate compression tests using a finite element model. HFSP J 2009; 3:273-81. [PMID: 20057960 DOI: 10.2976/1.3175812] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 06/20/2009] [Indexed: 12/26/2022]
Abstract
Although previous studies suggested that the interfacial tension gamma(cc) acting along cell-cell boundaries and the effective viscosity mu of the cell cytoplasm could be measured by compressing a spherical aggregate of cells between parallel plates, the mechanical understanding necessary to extract this information from these tests-tests that have provided the surface tension sigma(cm) acting along cell-medium interfaces-has been lacking. These tensions can produce net forces at the subcellular level and give rise to cell motions and tissue reorganization, the rates of which are regulated by mu. Here, a three-dimensional (3D) cell-based finite element model provides insight into the mechanics of the compression test, where these same forces are at work, and leads to quantitative relationships from which the effective viscosity mu of the cell cytoplasm, the tension gamma(cc) that acts along internal cell-cell interfaces and the surface tension sigma(cp) along the cell-platen boundaries can be determined from force-time curves and aggregate profiles. Tests on 5-day embryonic chick mesencephalon, neural retina, liver, and heart aggregates show that all of these properties vary significantly with cell type, except gamma(cc), which is remarkably constant. These properties are crucial for understanding cell rearrangement and tissue self-organization in contexts that include embryogenesis, cancer metastases, and tissue engineering.
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Mgharbel A, Delanoë-Ayari H, Rieu JP. Measuring accurately liquid and tissue surface tension with a compression plate tensiometer. HFSP J 2009; 3:213-21. [PMID: 19949443 DOI: 10.2976/1.3116822] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 03/20/2009] [Indexed: 01/17/2023]
Abstract
Apparent tissue surface tension allows the quantification of cell-cell cohesion and was reported to be a powerful indicator for the cellular rearrangements that take place during embryonic development or for cancer progression. The measurement is realized with a parallel compression plate tensiometer using the capillary laws. Although it was introduced more than a decade ago, it is based on various geometrical or physical approximations. Surprisingly, these approximations have never been tested. Using a novel tensiometer, we compare the two currently used methods to measure tissue surface tension and propose a third one, based on a local polynomial fit (LPF) of the profile of compressed droplets or cell aggregates. We show the importance of measuring the contact angle between the plate and the dropaggregate to obtain real accurate measurement of surface tension when applying existing methods. We can suspect that many reported values of surface tension are greatly affected because of not handling this parameter properly. We show then the benefit of using the newly introduced LPF method, which is not dependent on this parameter. These findings are confirmed by generating numerically compressed droplet profiles and testing the robustness and the sensitivity to errors of the different methods.
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Affiliation(s)
- Abbas Mgharbel
- Université de Lyon, Université de Lyon I, Laboratoire de Physique de la Matière Condensée et des Nanostructures, CNRS, UMR 5586, 43 Boulevard du 11 Nov. 1918, 69622 Villeurbanne Cedex, France
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39
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Kalantarian A, Ninomiya H, Saad SM, David R, Winklbauer R, Neumann AW. Axisymmetric drop shape analysis for estimating the surface tension of cell aggregates by centrifugation. Biophys J 2009; 96:1606-16. [PMID: 19217876 DOI: 10.1016/j.bpj.2008.10.064] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 10/08/2008] [Indexed: 11/21/2022] Open
Abstract
Biological tissues behave in certain respects like liquids. Consequently, the surface tension concept can be used to explain aspects of the in vitro and in vivo behavior of multicellular aggregates. Unfortunately, conventional methods of surface tension measurement cannot be readily applied to small cell aggregates. This difficulty can be overcome by an experimentally straightforward method consisting of centrifugation followed by axisymmetric drop shape analysis (ADSA). Since the aggregates typically show roughness, standard ADSA cannot be applied and we introduce a novel numerical method called ADSA-IP (ADSA for imperfect profile) for this purpose. To examine the new methodology, embryonic tissues from the gastrula of the frog, Xenopus laevis, deformed in the centrifuge are used. It is confirmed that surface tension measurements are independent of centrifugal force and aggregate size. Surface tension is measured for ectodermal cells in four sample batches, and varies between 1.1 and 7.7 mJ/m2. Surface tension is also measured for aggregates of cells expressing cytoplasmically truncated EP/C-cadherin, and is approximately half as large. In parallel, such aggregates show a reduction in convergent extension-driven elongation after activin treatment, reflecting diminished intercellular cohesion.
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40
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Abstract
How sensitive is morphogenesis to the mechanical properties of embryos? To estimate an upper bound on the sensitivity of early morphogenetic movements to tissue mechanical properties, we assessed natural variability in the apparent stiffness among gastrula-stage Xenopus laevis embryos. We adapted micro-aspiration methods to make repeated, nondestructive measurements of apparent tissue stiffness in whole embryos. Stiffness varied by close to a factor of 2 among embryos within a single clutch. Variation between clutches was of similar magnitude. On the other hand, the direction of change in stiffness over the course of gastrulation was the same in all embryos and in all clutches. Neither pH nor salinity--two environmental factors we predicted could affect variability in nature--affected tissue stiffness. Our results indicate that gastrulation in X. laevis is robust to at least twofold variation in tissue stiffness.
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Affiliation(s)
- Michelangelo von Dassow
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
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41
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Abstract
The amphibian gastrula can be regarded as a single coherent tissue which folds and distorts itself in a reproducible pattern to establish the embryonic germ layers. It is held together by cadherins which provide the flexible adhesion required for the massive cell rearrangements that accompany gastrulation. Cadherin expression and adhesiveness increase as one goes from the vegetal cell mass through the anterior mesendoderm to the chordamesoderm, and then decrease again slightly in the ectoderm. Together with a basic random component of cell motility, this flexible, differentially expressed adhesiveness generates surface and interfacial tension effects which, in principle, can exert strong forces. However, conclusive evidence for an in vivo role of differential adhesion-related effects in gastrula morphogenesis is still lacking. The most important morphogenetic process in the amphibian gastrula seems to be intercellular migration, where cells crawl actively across each other's surface. The crucial aspect of this process is that cell motility is globally oriented, leading for example to mediolateral intercalation of bipolar cells during convergent extension of the chordamesoderm or to the directional migration of unipolar cells during translocation of the anterior mesendoderm on the ectodermal blastocoel roof. During these movements, the boundary between ectoderm and mesoderm is maintained by a tissue separation process.
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Affiliation(s)
- Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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42
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Jakab K, Damon B, Marga F, Doaga O, Mironov V, Kosztin I, Markwald R, Forgacs G. Relating cell and tissue mechanics: Implications and applications. Dev Dyn 2008; 237:2438-49. [DOI: 10.1002/dvdy.21684] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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43
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Nusinow D, Greenberg L, Hatini V. Reciprocal roles for bowl and lines in specifying the peripodial epithelium and the disc proper of the Drosophila wing primordium. Development 2008; 135:3031-41. [PMID: 18701548 DOI: 10.1242/dev.020800] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Central to embryonic development is the generation of molecular asymmetries across fields of undifferentiated cells. The Drosophila wing imaginal disc provides a powerful system with which to understand how such asymmetries are generated and how they contribute to formation of a complex structure. Early in development, the wing primordium is subdivided into a thin layer of peripodial epithelium (PE) and an apposing thickened layer of pseudostratified columnar epithelium (CE), known as the disc proper (DP). The DP gives rise to the wing blade, hinge and dorsal mesothorax, whereas the PE makes only a minor contribution to the ventral hinge and pleura. The mechanisms that generate this major asymmetry and its contribution to wing development are poorly understood. The Lines protein destabilizes the nuclear protein Bowl in ectodermal structures. Here, we show that Bowl accumulates in the PE from early stages of wing development and is absent from the DP. Broad inhibition of Bowl in the PE resulted in the replacement of the PE with a mirror image duplication of the DP. The failure to generate the PE severely compromised wing growth and the formation of the notum. Conversely, the activation of bowl in the DP (by removal or inhibition of lines function) resulted in the transformation of the DP into PE. Thus, we provide evidence that bowl and lines act as a binary switch to subdivide the wing primordium into PE and DP, and assign crucial roles for this asymmetry in wing growth and patterning.
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Affiliation(s)
- David Nusinow
- Program in Cell, Molecular and Developmental Biology, 150 Harrison Avenue, Boston, MA 02111, USA
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44
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Abstract
We discuss the physical aspects of the morphogenic process of convergence (narrowing) and extension (lengthening) of tissues by cell intercalation. These movements, often referred to as 'convergent extension', occur in both epithelial and mesenchymal tissues during embryogenesis and organogenesis of invertebrates and vertebrates, and they play large roles in shaping the body plan during development. Our focus is on the presumptive mesodermal and neural tissues of the Xenopus (frog) embryo, tissues for which some physical measurements have been made. We discuss the physical aspects of how polarized cell motility, oriented along future tissue axes, generate the forces that drive oriented cell intercalation and how this intercalation results in convergence and extension or convergence and thickening of the tissue. Our goal is to identify aspects of these morphogenic movements for further biophysical, molecular and cell biological, and modeling studies.
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Affiliation(s)
- Ray Keller
- Department of Biology, University of Virginia, Charlottesville, VA, USA
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45
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Krieg M, Arboleda-Estudillo Y, Puech PH, Käfer J, Graner F, Müller DJ, Heisenberg CP. Tensile forces govern germ-layer organization in zebrafish. Nat Cell Biol 2008; 10:429-36. [PMID: 18364700 DOI: 10.1038/ncb1705] [Citation(s) in RCA: 539] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 01/28/2008] [Indexed: 01/27/2023]
Abstract
Understanding the factors that direct tissue organization during development is one of the most fundamental goals in developmental biology. Various hypotheses explain cell sorting and tissue organization on the basis of the adhesive and mechanical properties of the constituent cells. However, validating these hypotheses has been difficult due to the lack of appropriate tools to measure these parameters. Here we use atomic force microscopy (AFM) to quantify the adhesive and mechanical properties of individual ectoderm, mesoderm and endoderm progenitor cells from gastrulating zebrafish embryos. Combining these data with tissue self-assembly in vitro and the sorting behaviour of progenitors in vivo, we have shown that differential actomyosin-dependent cell-cortex tension, regulated by Nodal/TGFbeta-signalling (transforming growth factor beta), constitutes a key factor that directs progenitor-cell sorting. These results demonstrate a previously unrecognized role for Nodal-controlled cell-cortex tension in germ-layer organization during gastrulation.
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46
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von Dassow M, Davidson LA. Variation and robustness of the mechanics of gastrulation: the role of tissue mechanical properties during morphogenesis. ACTA ACUST UNITED AC 2008; 81:253-69. [PMID: 18228257 DOI: 10.1002/bdrc.20108] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Diverse mechanisms of morphogenesis generate a wide variety of animal forms. In this work, we discuss two ways that the mechanical properties of embryonic tissues could guide one of the earliest morphogenetic movements in animals, gastrulation. First, morphogenetic movements are a function of both the forces generated by cells and the mechanical properties of the tissues. Second, cells could change their behavior in response to their mechanical environment. Theoretical studies of gastrulation indicate that different morphogenetic mechanisms differ in their inherent sensitivity to tissue mechanical properties. Those few empirical studies that have investigated the mechanical properties of amphibian and echinoderm gastrula-stage embryos indicate that there could be high embryo-to-embryo variability in tissue stiffness. Such high embryo-to-embryo variability would imply that gastrulation is fairly robust to variation in tissue stiffness. Cell culture studies demonstrate a wide variety of cellular responses to the mechanical properties of their microenvironment. These responses are likely to be developmentally regulated, and could either increase or decrease the robustness of gastrulation movements depending on which cells express which responses. Hence both passive physical and mechanoregulatory processes will determine how sensitive gastrulation is to tissue mechanics. Addressing these questions is important for understanding the significance of diverse programs of early development, and how genetic or environmental perturbations influence development. We discuss methods for measuring embryo-to-embryo variability in tissue mechanics, and for experimentally perturbing those mechanical properties to determine the sensitivity of gastrulation to tissue mechanics.
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47
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Schötz EM, Burdine RD, Jülicher F, Steinberg MS, Heisenberg CP, Foty RA. Quantitative differences in tissue surface tension influence zebrafish germ layer positioning. HFSP J 2008; 2:42-56. [PMID: 19404452 PMCID: PMC2640996 DOI: 10.2976/1.2834817] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Indexed: 11/19/2022]
Abstract
This study provides direct functional evidence that differential adhesion, measurable as quantitative differences in tissue surface tension, influences spatial positioning between zebrafish germ layer tissues. We show that embryonic ectodermal and mesendodermal tissues generated by mRNA-overexpression behave on long-time scales like immiscible fluids. When mixed in hanging drop culture, their cells segregate into discrete phases with ectoderm adopting an internal position relative to the mesendoderm. The position adopted directly correlates with differences in tissue surface tension. We also show that germ layer tissues from untreated embryos, when extirpated and placed in culture, adopt a configuration similar to those of their mRNA-overexpressing counterparts. Down-regulating E-cadherin expression in the ectoderm leads to reduced surface tension and results in phase reversal with E-cadherin-depleted ectoderm cells now adopting an external position relative to the mesendoderm. These results show that in vitro cell sorting of zebrafish mesendoderm and ectoderm tissues is specified by tissue interfacial tensions. We perform a mathematical analysis indicating that tissue interfacial tension between actively motile cells contributes to the spatial organization and dynamics of these zebrafish germ layers in vivo.
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Affiliation(s)
- Eva-Maria Schötz
- Max-Planck-Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany
| | - Rebecca D. Burdine
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08540
| | - Frank Jülicher
- Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany
| | - Malcolm S. Steinberg
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08540
- New Jersey Center for Biomaterials, Rutgers University, Piscataway, New Jersey 08544
| | | | - Ramsey A. Foty
- UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey 08901
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Ninomiya H, Winklbauer R. Epithelial coating controls mesenchymal shape change through tissue-positioning effects and reduction of surface-minimizing tension. Nat Cell Biol 2008; 10:61-9. [PMID: 18084283 DOI: 10.1038/ncb1669] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 11/26/2007] [Indexed: 01/22/2023]
Abstract
Signalling between mesenchymal and epithelial cells has a profound influence on organ morphogenesis. However, less is known about the mechanical function of epithelial-mesenchymal interactions. Here, we describe two principal effects by which epithelia can regulate shape changes in mesenchymal cell aggregates. We propose that during formation of the embryonic body axis, the epithelial layer relieves surface minimizing tensions that would force cell aggregates into a spherical shape, and controls the serial arrangement of cell populations along the axis. The combined effects permit the tissue to deviate from a spherical form and to elongate.
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49
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Abstract
The organization of endocrine cells in pancreatic islets is established through a series of morphogenetic events involving cell sorting, migration, and re-aggregation processes for which intercellular adhesion is thought to play a central role. In animals, these morphogenetic events result in an islet topology in which insulin-secreting cells form the core, while glucagon, somatostatin, and pancreatic polypeptide-secreting cells segregate to the periphery. Isolated pancreatic islet cells self-assemble in vitro into pseudoislets with the same cell type organization as native islets. It is widely held that differential adhesion between cells of the pancreatic islets generates this specific topology. However, this differential adhesion has never been rigorously quantified. In this manuscript, we use tissue surface tensiometry to measure the cohesivity of spherical aggregates from three immortalized mouse pancreatic islet cell lines. We show that, as predicted by the differential adhesion hypothesis, aggregates of the internally segregating INS-1 and MIN6 beta-cell lines are substantially more cohesive than those of the externally segregating alpha-TC line. Furthermore, we show that forced overexpression of P-cadherin by alpha-TC cells significantly perturbs the sorting process. Collectively, the data indicate that differential adhesion can drive the in vitro organization of immortalized rodent pancreatic islet cells.
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Affiliation(s)
- Dongxuan Jia
- Department of Surgery, UMDNJ, Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
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50
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Lachnit M, Kur E, Driever W. Alterations of the cytoskeleton in all three embryonic lineages contribute to the epiboly defect of Pou5f1/Oct4 deficient MZspg zebrafish embryos. Dev Biol 2007; 315:1-17. [PMID: 18215655 DOI: 10.1016/j.ydbio.2007.10.008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2007] [Revised: 10/03/2007] [Accepted: 10/05/2007] [Indexed: 01/23/2023]
Abstract
Pou5f1/Oct4 is a transcription factor required for pluripotency of embryonic stem cells in mammals. Zebrafish pou5f1 deficient maternal and zygotic spiel ohne grenzen (MZspg) mutant embryos develop severe gastrulation defects, are dorsalized, and defective in endoderm formation. Here we analyze in detail gastrulation defects, which are manifested by a severe delay in epiboly progression. All three embryonic lineages in MZspg embryos behave abnormally during epiboly: the yolk cell forms an altered array of cortical microtubules and F-Actin, with large patches of microtubule free areas; the enveloping layer (EVL) is delayed in the coordinated cell shape changes of marginal cells, that may be mediated by F-Actin; the deep layer cells (DEL), forming the embryo proper, are non-autonomously affected in their motility and do not enter the space opening by epiboly of the EVL. Analysis of adhesiveness as well as high resolution in vivo time lapse image analysis of DEL cells suggests changed adhesive properties and inability to migrate properly on EVL and yolk syncytial layer (YSL) surfaces. Our data further reveal that during epiboly the EVL may actively probe the YSL by filopodia formation, rather than just being passively pulled vegetalwards. Our findings on the effect of Pou5f1 on cell behavior may be relevant to understand stem cell behavior and tumorigenesis involving Pou5f1.
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Affiliation(s)
- Martina Lachnit
- Department of Developmental Biology, Institute Biology 1, University of Freiburg, 79104 Freiburg, Germany
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