151
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Sugihara K, Sasaki S, Uemura A, Kidoaki S, Miura T. Mechanisms of endothelial cell coverage by pericytes: computational modelling of cell wrapping and in vitro experiments. J R Soc Interface 2020; 17:20190739. [PMID: 31992164 DOI: 10.1098/rsif.2019.0739] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Pericytes (PCs) wrap around endothelial cells (ECs) and perform diverse functions in physiological and pathological processes. Although molecular interactions between ECs and PCs have been extensively studied, the morphological processes at the cellular level and their underlying mechanisms have remained elusive. In this study, using a simple cellular Potts model, we explored the mechanisms for EC wrapping by PCs. Based on the observed in vitro cell wrapping in three-dimensional PC-EC coculture, the model identified four putative contributing factors: preferential adhesion of PCs to the extracellular matrix (ECM), strong cell-cell adhesion, PC surface softness and larger PC size. While cell-cell adhesion can contribute to the prevention of cell segregation and the degree of cell wrapping, it cannot determine the orientation of cell wrapping alone. While atomic force microscopy revealed that PCs have a larger Young's modulus than ECs, the experimental analyses supported preferential ECM adhesion and size asymmetry. We also formulated the corresponding energy minimization problem and numerically solved this problem for specific cases. These results give biological insights into the role of PC-ECM adhesion in PC coverage. The modelling framework presented here should also be applicable to other cell wrapping phenomena observed in vivo.
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Affiliation(s)
- Kei Sugihara
- Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Saori Sasaki
- Laboratory of Biomedical and Biophysical Chemistry, Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, Japan
| | - Akiyoshi Uemura
- Department of Retinal Vascular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Satoru Kidoaki
- Laboratory of Biomedical and Biophysical Chemistry, Institute for Materials Chemistry and Engineering, Kyushu University, Fukuoka, Japan
| | - Takashi Miura
- Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,CREST, Japan Science and Technology Agency, Kawaguchi, Japan
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152
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Barzegari A, Gueguen V, Omidi Y, Ostadrahimi A, Nouri M, Pavon‐Djavid G. The role of Hippo signaling pathway and mechanotransduction in tuning embryoid body formation and differentiation. J Cell Physiol 2020; 235:5072-5083. [DOI: 10.1002/jcp.29455] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 01/06/2020] [Indexed: 12/21/2022]
Affiliation(s)
- Abolfazl Barzegari
- Department of Medical Biotechnology, Faculty of Advanced Medical SciencesTabriz University of Medical Sciences Tabriz Iran
| | - Virginie Gueguen
- INSERM U1148, Laboratory for Vascular Translational Science, Cardiovascular BioengineeringUniversité Paris 13 Paris France
| | - Yadollah Omidi
- Research Center for Pharmaceutical NanotechnologyTabriz University of Medical Sciences Tabriz Iran
- Department of Pharmaceutics, Faculty of PharmacyTabriz University of Medical Sciences Tabriz Iran
| | - Alireza Ostadrahimi
- Nutrition Research CenterTabriz University of Medical Sciences Tabriz Iran
- Department of Clinical Nutrition, Faculty of Nutrition and Food SciencesTabriz University of Medical Sciences Tabriz Iran
| | - Mohammad Nouri
- Department of Medical Biotechnology, Faculty of Advanced Medical SciencesTabriz University of Medical Sciences Tabriz Iran
- Department of Clinical Biochemistry and Laboratory Medicine, Faculty of MedicineTabriz University of Medical Sciences Tabriz Iran
| | - Graciela Pavon‐Djavid
- INSERM U1148, Laboratory for Vascular Translational Science, Cardiovascular BioengineeringUniversité Paris 13 Paris France
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153
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Zhu M, Zernicka-Goetz M. Building an apical domain in the early mouse embryo: Lessons, challenges and perspectives. Curr Opin Cell Biol 2019; 62:144-149. [PMID: 31869760 DOI: 10.1016/j.ceb.2019.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 11/21/2019] [Indexed: 01/09/2023]
Abstract
Cell polarization is critical for lineage segregation and morphogenesis during mammalian embryogenesis. However, the processes and mechanisms that establish cell polarity in the mammalian embryo are not well understood. Recent studies suggest that unique regulatory mechanisms are deployed by the mouse embryo to establish cell polarization. In this review, we discuss the current understanding of cell polarity establishment, focusing on the formation of the apical domain in the mouse embryo. We will also discuss outstanding questions and possible directions for future study.
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Affiliation(s)
- Meng Zhu
- Mammalian Embryo and Stem Cell Group, University of Cambridge, Department of Physiology, Development and Neuroscience, Downing Street, Cambridge, CB2 3DY, UK
| | - Magdalena Zernicka-Goetz
- Mammalian Embryo and Stem Cell Group, University of Cambridge, Department of Physiology, Development and Neuroscience, Downing Street, Cambridge, CB2 3DY, UK.
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154
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Urbanczyk M, Layland SL, Schenke-Layland K. The role of extracellular matrix in biomechanics and its impact on bioengineering of cells and 3D tissues. Matrix Biol 2019; 85-86:1-14. [PMID: 31805360 DOI: 10.1016/j.matbio.2019.11.005] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 11/24/2019] [Accepted: 11/24/2019] [Indexed: 12/20/2022]
Abstract
The cells and tissues of the human body are constantly exposed to exogenous and endogenous forces that are referred to as biomechanical cues. They guide and impact cellular processes and cell fate decisions on the nano-, micro- and macro-scale, and are therefore critical for normal tissue development and maintaining tissue homeostasis. Alterations in the extracellular matrix composition of a tissue combined with abnormal mechanosensing and mechanotransduction can aberrantly activate signaling pathways that promote disease development. Such processes are therefore highly relevant for disease modelling or when aiming for the development of novel therapies. In this mini review, we describe the main biomechanical cues that impact cellular fates. We highlight their role during development, homeostasis and in disease. We also discuss current techniques and tools that allow us to study the impact of biomechanical cues on cell and tissue development under physiological conditions, and we point out directions, in which in vitro biomechanics can be of use in the future.
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Affiliation(s)
- Max Urbanczyk
- Department of Women's Health, Research Institute of Women's Health, Eberhard Karls University Tübingen, Germany
| | - Shannon L Layland
- Department of Women's Health, Research Institute of Women's Health, Eberhard Karls University Tübingen, Germany
| | - Katja Schenke-Layland
- Department of Women's Health, Research Institute of Women's Health, Eberhard Karls University Tübingen, Germany; Natural and Medical Sciences Institute (NMI) at the University of Tübingen, Reutlingen, Germany; Cluster of Excellence IFIT (EXC 2180), "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University Tübingen, Germany; Dept. of Medicine/Cardiology, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
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155
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Yao C, Zhang W, Shuai L. The first cell fate decision in pre-implantation mouse embryos. CELL REGENERATION 2019; 8:51-57. [PMID: 31844518 PMCID: PMC6895705 DOI: 10.1016/j.cr.2019.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 10/14/2019] [Accepted: 10/16/2019] [Indexed: 10/27/2022]
Abstract
Fertilization happens when sperm and oocytes meet, which is a complicated process involving many important types of biological activation. Beginning in the 2-cell stage, an important event referred to as zygotic genome activation (ZGA) occurs, which governs the subsequent development of the embryo. In ZGA, multiple epigenetic modifications are involved and critical for pre-implantation development. These changes occur after ZGA, resulting in blastomeres segregate into two different lineages. Some blastomeres develop into the inner cell mass (ICM), and others develop into the trophectoderm (TE), which is considered the first cell fate decision. How this process is initiated and the exact molecular mechanisms involved are fascinating questions that remain to be answered. In this review, we introduce some possible developmental models of the first cell fate decision and discuss the signalling pathways and transcriptional networks regulating this process.
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Affiliation(s)
- Chunmeng Yao
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin, 300350, China
| | - Wenhao Zhang
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin, 300350, China
| | - Ling Shuai
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy, Nankai University, Tianjin, 300350, China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
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156
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Abstract
Early embryogenesis is characterized by the segregation of cell lineages that fulfill critical roles in the establishment of pregnancy and development of the fetus. The formation of the blastocyst marks the emergence of extraembryonic precursors, needed for implantation, and of pluripotent cells, which differentiate toward the major lineages of the adult organism. The coordinated emergence of these cell types shows that these processes are broadly conserved in mammals. However, developmental heterochrony and changes in gene regulatory networks highlight unique evolutionary adaptations that may explain the diversity in placentation and in the mechanisms controlling pluripotency in mammals. The incorporation of new technologies, including single-cell omics, imaging, and gene editing, is instrumental for comparative embryology. Broadening the knowledge of mammalian embryology will provide new insights into the mechanisms driving evolution and development. This knowledge can be readily translated into biomedical and biotechnological applications in humans and livestock, respectively.
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Affiliation(s)
- Ramiro Alberio
- School of Biosciences, University of Nottingham, Nottingham NG7 2RD, United Kingdom;
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157
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Ryan AQ, Chan CJ, Graner F, Hiiragi T. Lumen Expansion Facilitates Epiblast-Primitive Endoderm Fate Specification during Mouse Blastocyst Formation. Dev Cell 2019; 51:684-697.e4. [PMID: 31735667 PMCID: PMC6912163 DOI: 10.1016/j.devcel.2019.10.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/29/2019] [Accepted: 10/14/2019] [Indexed: 12/21/2022]
Abstract
Epithelial tissues typically form lumina. In mammalian blastocysts, in which the first embryonic lumen forms, many studies have investigated how the cell lineages are specified through genetics and signaling, whereas potential roles of the fluid lumen have yet to be investigated. We discover that in mouse pre-implantation embryos at the onset of lumen formation, cytoplasmic vesicles are secreted into intercellular space. The segregation of epiblast and primitive endoderm directly follows lumen coalescence. Notably, pharmacological and biophysical perturbation of lumen expansion impairs the specification and spatial segregation of primitive endoderm cells within the blastocyst. Luminal deposition of FGF4 expedites fate specification and partially rescues the reduced specification in blastocysts with smaller cavities. Combined, our results suggest that blastocyst lumen expansion plays a critical role in guiding cell fate specification and positioning, possibly mediated by luminally deposited FGF4. Lumen expansion may provide a general mechanism for tissue pattern formation. Lumenogenesis coincides with cytoplasmic vesicle release into intercellular space Mouse blastocyst epiblast-primitive endoderm segregation follows lumen expansion Reduced lumen expansion impairs cell fate specification and segregation Luminally deposited FGF4 expedites epiblast-primitive endoderm specification
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Affiliation(s)
- Allyson Quinn Ryan
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; Laboratoire Matière et Systèmes Complexes, Université Denis Diderot, Paris 7, CNRS UMR 7057, Condorcet Building 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
| | - Chii Jou Chan
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - François Graner
- Laboratoire Matière et Systèmes Complexes, Université Denis Diderot, Paris 7, CNRS UMR 7057, Condorcet Building 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
| | - Takashi Hiiragi
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan.
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158
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Niwayama R, Moghe P, Liu YJ, Fabrèges D, Buchholz F, Piel M, Hiiragi T. A Tug-of-War between Cell Shape and Polarity Controls Division Orientation to Ensure Robust Patterning in the Mouse Blastocyst. Dev Cell 2019; 51:564-574.e6. [PMID: 31735668 PMCID: PMC6892278 DOI: 10.1016/j.devcel.2019.10.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 07/04/2019] [Accepted: 10/14/2019] [Indexed: 01/08/2023]
Abstract
Oriented cell division patterns tissues by modulating cell position and fate. While cell geometry, junctions, cortical tension, and polarity are known to control division orientation, relatively little is known about how these are coordinated to ensure robust patterning. Here, we systematically characterize cell division, volume, and shape changes during mouse pre-implantation development by in toto live imaging. The analysis leads us to a model in which the apical domain competes with cell shape to determine division orientation. Two key predictions of the model are verified experimentally: when outside cells of the 16-cell embryo are released from cell shape asymmetry, the axis of division is guided by the apical domain. Conversely, orientation cues from the apical domain can be overcome by applied shape asymmetry in the 8-cell embryo. We propose that such interplay between cell shape and polarity in controlling division orientation ensures robust patterning of the blastocyst and possibly other tissues. Cell division, volume, and shape changes are characterized by in toto embryo imaging Cell shape and the apical domain compete to determine division orientation Two key predictions of the model are verified experimentally The tug-of-war mechanism ensures robust cell allocation and patterning
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Affiliation(s)
- Ritsuya Niwayama
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Prachiti Moghe
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Yan-Jun Liu
- UMR 144 Institut Curie, Institut Pierre Gilles de Gennes for Microfluidics, Paris, France
| | - Dimitri Fabrèges
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Frank Buchholz
- Medical Systems Biology, UCC, University Hospital and Medical Faculty Carl Gustav Carus, TU Dresden, Dresden, Germany
| | - Matthieu Piel
- UMR 144 Institut Curie, Institut Pierre Gilles de Gennes for Microfluidics, Paris, France
| | - Takashi Hiiragi
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany; Institute for Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan.
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159
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Motegi F, Plachta N, Viasnoff V. Novel approaches to link apicobasal polarity to cell fate specification. Curr Opin Cell Biol 2019; 62:78-85. [PMID: 31731147 DOI: 10.1016/j.ceb.2019.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/19/2019] [Accepted: 09/26/2019] [Indexed: 12/26/2022]
Abstract
Understanding the development of apicobasal polarity (ABP) is a long-standing problem in biology. The molecular components involved in the development and maintenance of APB have been largely identified and are known to have ubiquitous roles across organisms. Our knowledge of the functional consequences of ABP establishment and maintenance is far less comprehensive. Recent studies using novel experimental approaches and cellular models have revealed a growing link between ABP and the genetic program of cell lineage. This mini-review describes some of the most recent advances in this new field, highlighting examples from Caenorhabditis elegans and mouse embryos, human pluripotent stem cells, and epithelial cells. We also speculate on the most interesting and challenging avenues that can be explored.
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Affiliation(s)
- Fumio Motegi
- Department of Biological Sciences, National University of Singapore, 117583, Singapore; Mechanobiology Institute, National University of Singapore, 117 411, Singapore; Temasek Life-sciences Laboratory, 117604, Singapore; Contributed equally
| | - Nicolas Plachta
- Institute of Molecular and Cell Biology, ASTAR, Singapore; Contributed equally
| | - Virgile Viasnoff
- Department of Biological Sciences, National University of Singapore, 117583, Singapore; Mechanobiology Institute, National University of Singapore, 117 411, Singapore; CNRS, 117411, Singapore; Contributed equally.
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160
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aPKCi triggers basal extrusion of luminal mammary epithelial cells by tuning contractility and vinculin localization at cell junctions. Proc Natl Acad Sci U S A 2019; 116:24108-24114. [PMID: 31699818 PMCID: PMC6883778 DOI: 10.1073/pnas.1906779116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
This study shows that an oncogenic mammary epithelial cell surrounded by normal cells can extrude basally in vivo and invade surrounding tissues without formation of a primary tumor. Here, we show that overexpression of the key polarity protein atypical protein kinase C ι (aPKCi) is sufficient for triggering basally oriented epithelial cell extrusion and early cell invasion into the mammary gland stroma. Moreover, we highlight the importance of the difference between the mechanical properties of aPKCi-overexpressing cells and those of the normal surrounding cells associated with the decrease of vinculin at the cell junction, which triggers cell segregation, the first step toward promoting and controlling the direction of cell extrusion. Metastasis is the main cause of cancer-related deaths. How a single oncogenic cell evolves within highly organized epithelium is still unknown. Here, we found that the overexpression of the protein kinase atypical protein kinase C ι (aPKCi), an oncogene, triggers basally oriented epithelial cell extrusion in vivo as a potential mechanism for early breast tumor cell invasion. We found that cell segregation is the first step required for basal extrusion of luminal cells and identify aPKCi and vinculin as regulators of cell segregation. We propose that asymmetric vinculin levels at the junction between normal and aPKCi+ cells trigger an increase in tension at these cell junctions. Moreover, we show that aPKCi+ cells acquire promigratory features, including increased vinculin levels and vinculin dynamics at the cell–substratum contacts. Overall, this study shows that a balance between cell contractility and cell–cell adhesion is crucial for promoting basally oriented cell extrusion, a mechanism for early breast cancer cell invasion.
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161
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Abstract
Cells are arranged into species-specific patterns during early embryogenesis. Such cell division patterns are important since they often reflect the distribution of localized cortical factors from eggs/fertilized eggs to specific cells as well as the emergence of organismal form. However, it has proven difficult to reveal the mechanisms that underlie the emergence of cell positioning patterns that underlie embryonic shape, likely because a systems-level approach is required that integrates cell biological, genetic, developmental, and mechanical parameters. The choice of organism to address such questions is also important. Because ascidians display the most extreme form of invariant cleavage pattern among the metazoans, we have been analyzing the cell biological mechanisms that underpin three aspects of cell division (unequal cell division (UCD), oriented cell division (OCD), and asynchronous cell cycles) which affect the overall shape of the blastula-stage ascidian embryo composed of 64 cells. In ascidians, UCD creates two small cells at the 16-cell stage that in turn undergo two further successive rounds of UCD. Starting at the 16-cell stage, the cell cycle becomes asynchronous, whereby the vegetal half divides before the animal half, thus creating 24-, 32-, 44-, and then 64-cell stages. Perturbing either UCD or the alternate cell division rhythm perturbs cell position. We propose that dynamic cell shape changes propagate throughout the embryo via cell-cell contacts to create the ascidian-specific invariant cleavage pattern.
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162
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Lenzini S, Devine D, Shin JW. Leveraging Biomaterial Mechanics to Improve Pluripotent Stem Cell Applications for Tissue Engineering. Front Bioeng Biotechnol 2019; 7:260. [PMID: 31649928 PMCID: PMC6795675 DOI: 10.3389/fbioe.2019.00260] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 09/26/2019] [Indexed: 12/31/2022] Open
Abstract
A primary goal in tissue engineering is to develop functional tissues by recapitulating salient features of complex biological systems that exhibit a diverse range of physical forces. Induced pluripotent stem cells (iPSCs) are promising autologous cell sources to execute these developmental programs and their functions; however, cells require an extracellular environment where they will sense and respond to mechanical forces. Thus, understanding the biophysical relationships between stem cells and their extracellular environments will improve the ability to design complex biological systems through tissue engineering. This article first describes how the mechanical properties of the environment are important determinants of developmental processes, and then further details how biomaterials can be designed to precisely control the mechanics of cell-matrix interactions in order to study and define their reprogramming, self-renewal, differentiation, and morphogenesis. Finally, a perspective is presented on how insights from the mechanics of cell-matrix interactions can be leveraged to control pluripotent stem cells for tissue engineering applications.
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Affiliation(s)
- Stephen Lenzini
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, United States
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Daniel Devine
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, United States
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Jae-Won Shin
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL, United States
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
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163
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Dutta P, Odedra D, Pohl C. Planar Asymmetries in the C. elegans Embryo Emerge by Differential Retention of aPARs at Cell-Cell Contacts. Front Cell Dev Biol 2019; 7:209. [PMID: 31612135 PMCID: PMC6776615 DOI: 10.3389/fcell.2019.00209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/11/2019] [Indexed: 01/08/2023] Open
Abstract
Formation of the anteroposterior and dorsoventral body axis in Caenorhabditis elegans depends on cortical flows and advection of polarity determinants. The role of this patterning mechanism in tissue polarization after formation of cell-cell contacts is not fully understood. Here, we demonstrate that planar asymmetries are established during left-right symmetry breaking: Centripetal cortical flows asymmetrically and differentially advect anterior polarity determinants (aPARs) from contacts to the medial cortex, resulting in their unmixing from apical myosin. Contact localization and advection of PAR-6 requires balanced CDC-42 activation, while asymmetric retention and advection of PAR-3 can occur independently of PAR-6. Concurrent asymmetric retention of PAR-3, E-cadherin/HMR-1 and opposing retention of antagonistic CDC-42 and Wnt pathway components leads to planar asymmetries. The most obvious mark of planar asymmetry, retention of PAR-3 at a single cell-cell contact, is required for proper cytokinetic cell intercalation. Hence, our data uncover how planar polarity is established in a system without the canonical planar cell polarity pathway through planar asymmetric retention of aPARs.
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Affiliation(s)
| | | | - Christian Pohl
- Medical Faculty, Buchmann Institute for Molecular Life Sciences, Institute of Biochemistry II, Goethe University, Frankfurt, Germany
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164
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Abstract
The Hippo signalling pathway and its transcriptional co-activator targets Yorkie/YAP/TAZ first came to attention because of their role in tissue growth control. Over the past 15 years, it has become clear that, like other developmental pathways (e.g. the Wnt, Hedgehog and TGFβ pathways), Hippo signalling is a 'jack of all trades' that is reiteratively used to mediate a range of cellular decision-making processes from proliferation, death and morphogenesis to cell fate determination. Here, and in the accompanying poster, we briefly outline the core pathway and its regulation, and describe the breadth of its roles in animal development.
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Affiliation(s)
- John Robert Davis
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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165
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Rezaei-Lotfi S, Hunter N, Farahani RM. Coupled cycling programs multicellular self-organization of neural progenitors. Cell Cycle 2019; 18:2040-2054. [PMID: 31286803 PMCID: PMC6681778 DOI: 10.1080/15384101.2019.1638692] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023] Open
Abstract
Self-organization is central to the morphogenesis of multicellular organisms. However, the molecular platform that coordinates the robust emergence of complex morphological patterns from local interactions between cells remains unresolved. Here we demonstrate that neural self- organization is driven by coupled cycling of progenitor cells. In a coupled cycling mode, intercellular contacts relay extrinsic cues to override the intrinsic cycling rhythm of an individual cell and synchronize the population. The stringency of coupling and hence the synchronicity of the population is programmed by recruitment of a key coupler, β-catenin, into junctional complexes. As such, multicellular self-organization is driven by the same basic mathematical principle that governs synchronized behavior of macro-scale biological systems as diverse as the synchronized chirping of crickets, flashing of fireflies and schooling of fish; that is synchronization by coupling. It is proposed that coupled cycling foreshadows a fundamental adaptive change that facilitated evolution and diversification of multicellular life forms.
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Affiliation(s)
- Saba Rezaei-Lotfi
- IDR/Westmead Institute for Medical Research, Sydney, NSW, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Neil Hunter
- IDR/Westmead Institute for Medical Research, Sydney, NSW, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Ramin M Farahani
- IDR/Westmead Institute for Medical Research, Sydney, NSW, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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166
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Abstract
Biochemical reactions are intrinsically stochastic, leading to variation in the production of mRNAs and proteins within cells. In the scientific literature, this source of variation is typically referred to as 'noise'. The observed variability in molecular phenotypes arises from a combination of processes that amplify and attenuate noise. Our ability to quantify cell-to-cell variability in numerous biological contexts has been revolutionized by recent advances in single-cell technology, from imaging approaches through to 'omics' strategies. However, defining, accurately measuring and disentangling the stochastic and deterministic components of cell-to-cell variability is challenging. In this Review, we discuss the sources, impact and function of molecular phenotypic variability and highlight future directions to understand its role.
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Affiliation(s)
- Nils Eling
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK.
- Wellcome Sanger Institute, Welcome Genome Campus, Hinxton, UK.
| | | | - John C Marioni
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, UK.
- Wellcome Sanger Institute, Welcome Genome Campus, Hinxton, UK.
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.
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167
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Doerr S, Ragkousi K. Cell polarity oscillations in mitotic epithelia. Curr Opin Genet Dev 2019; 57:47-53. [PMID: 31465986 DOI: 10.1016/j.gde.2019.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 12/21/2022]
Abstract
Epithelial organization and function depend on coordinated cell polarity. In developing tissues, proliferative epithelia maintain whole tissue polarity as individual cells undergo symmetric divisions. However, recent work has shown that cells in diverse epithelia remodel their polarity in a cell cycle-dependent manner. Here, we discuss the different mechanisms that drive mitotic polarity oscillations and their implications for tissue morphogenesis.
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Affiliation(s)
- Sophia Doerr
- Department of Biology, Amherst College, Amherst, MA 01002, United States; Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, United States
| | - Katerina Ragkousi
- Department of Biology, Amherst College, Amherst, MA 01002, United States; Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, United States.
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168
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Dumortier JG, Le Verge-Serandour M, Tortorelli AF, Mielke A, de Plater L, Turlier H, Maître JL. Hydraulic fracturing and active coarsening position the lumen of the mouse blastocyst. Science 2019; 365:465-468. [DOI: 10.1126/science.aaw7709] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/12/2019] [Indexed: 12/14/2022]
Abstract
During mouse pre-implantation development, the formation of the blastocoel, a fluid-filled lumen, breaks the radial symmetry of the blastocyst. The factors that control the formation and positioning of this basolateral lumen remain obscure. We found that accumulation of pressurized fluid fractures cell-cell contacts into hundreds of micrometer-size lumens. These microlumens eventually discharge their volumes into a single dominant lumen, which we model as a process akin to Ostwald ripening, underlying the coarsening of foams. Using chimeric mutant embryos, we tuned the hydraulic fracturing of cell-cell contacts and steered the coarsening of microlumens, allowing us to successfully manipulate the final position of the lumen. We conclude that hydraulic fracturing of cell-cell contacts followed by contractility-directed coarsening of microlumens sets the first axis of symmetry of the mouse embryo.
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169
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Schliffka MF, Maître JL. Stay hydrated: basolateral fluids shaping tissues. Curr Opin Genet Dev 2019; 57:70-77. [DOI: 10.1016/j.gde.2019.06.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/15/2019] [Accepted: 06/21/2019] [Indexed: 01/29/2023]
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170
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Cong J, Fang B, Wang Q, Su Y, Gu T, Luo T. The mechanobiology of actin cytoskeletal proteins during cell-cell fusion. J R Soc Interface 2019; 16:20190022. [PMID: 31337301 DOI: 10.1098/rsif.2019.0022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Myosin II and spectrin β display mechanosensitive accumulations in invasive protrusions during cell-cell fusion of Drosophila myoblasts. The biochemical inhibition and deactivation of these proteins results in significant fusion defects. Yet, a quantitative understanding of how the protrusion geometry and fusion process are linked to these proteins is still lacking. Here we present a quantitative model to interpret the dependence of the protrusion size and the protrusive force on the mechanical properties and microstructures of the actin cytoskeleton and plasma membrane based on a mean-field theory. We build a quantitative linkage between mechanosensitive accumulation of myosin II and fusion pore formation at the tip of the invasive protrusion through local area dilation. The mechanical feedback loop between myosin II and local deformation suggests that myosin II accumulation possibly reduces the energy barrier and the critical radius of fusion pores. We also analyse the effect of spectrin β on maintaining the proper geometry of the protrusions required for the success of cell-cell fusion.
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Affiliation(s)
- Jing Cong
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Bing Fang
- College of Mechanical and Electronic Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, People's Republic of China
| | - Qian Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Yan Su
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, People's Republic of China
| | - Tianqi Gu
- College of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, People's Republic of China
| | - Tianzhi Luo
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, People's Republic of China
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171
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Henderson BW, Greathouse KM, Ramdas R, Walker CK, Rao TC, Bach SV, Curtis KA, Day JJ, Mattheyses AL, Herskowitz JH. Pharmacologic inhibition of LIMK1 provides dendritic spine resilience against β-amyloid. Sci Signal 2019; 12:eaaw9318. [PMID: 31239325 PMCID: PMC7088434 DOI: 10.1126/scisignal.aaw9318] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) therapies predominantly focus on β-amyloid (Aβ), but Aβ effects may be maximal before clinical symptoms appear. Downstream of Aβ, dendritic spine loss correlates most strongly with cognitive decline in AD. Rho-associated kinases (ROCK1 and ROCK2) regulate the actin cytoskeleton, and ROCK1 and ROCK2 protein abundances are increased in early AD. Here, we found that the increased abundance of ROCK1 in cultured primary rat hippocampal neurons reduced dendritic spine length through a myosin-based pathway, whereas the increased abundance of ROCK2 induced spine loss through the serine and threonine kinase LIMK1. Aβ42 oligomers can activate ROCKs. Here, using static imaging studies combined with multielectrode array analyses, we found that the ROCK2-LIMK1 pathway mediated Aβ42-induced spine degeneration and neuronal hyperexcitability. Live-cell microscopy revealed that pharmacologic inhibition of LIMK1 rendered dendritic spines resilient to Aβ42 oligomers. Treatment of hAPP mice with a LIMK1 inhibitor rescued Aβ-induced hippocampal spine loss and morphologic aberrations. Our data suggest that therapeutically targeting LIMK1 may provide dendritic spine resilience to Aβ and therefore may benefit cognitively normal patients that are at high risk for developing dementia.
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Affiliation(s)
- Benjamin W Henderson
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
- Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Kelsey M Greathouse
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
- Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Raksha Ramdas
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
- Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Courtney K Walker
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
- Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Tejeshwar C Rao
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Svitlana V Bach
- Department of Neurobiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Kendall A Curtis
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
- Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Jeremy J Day
- Department of Neurobiology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Alexa L Mattheyses
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Jeremy H Herskowitz
- Center for Neurodegeneration and Experimental Therapeutics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA.
- Department of Neurology, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
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172
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Hydraulic control of mammalian embryo size and cell fate. Nature 2019; 571:112-116. [PMID: 31189957 DOI: 10.1038/s41586-019-1309-x] [Citation(s) in RCA: 187] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 05/21/2019] [Indexed: 11/08/2022]
Abstract
Size control is fundamental in tissue development and homeostasis1,2. Although the role of cell proliferation in these processes has been widely studied, the mechanisms that control embryo size-and how these mechanisms affect cell fate-remain unknown. Here we use the mouse blastocyst as a model to unravel a key role of fluid-filled lumen in the control of embryo size and specification of cell fate. We find that there is a twofold increase in lumenal pressure during blastocyst development, which translates into a concomitant increase in cell cortical tension and tissue stiffness of the trophectoderm that lines the lumen. Increased cortical tension leads to vinculin mechanosensing and maturation of functional tight junctions, which establishes a positive feedback loop to accommodate lumen growth. When the cortical tension reaches a critical threshold, cell-cell adhesion cannot be sustained during mitotic entry, which leads to trophectoderm rupture and blastocyst collapse. A simple theory of hydraulically gated oscillations recapitulates the observed dynamics of size oscillations, and predicts the scaling of embryo size with tissue volume. This theory further predicts that disrupted tight junctions or increased tissue stiffness lead to a smaller embryo size, which we verified by biophysical, embryological, pharmacological and genetic perturbations. Changes in lumenal pressure and size can influence the cell division pattern of the trophectoderm, and thereby affect cell allocation and fate. Our study reveals how lumenal pressure and tissue mechanics control embryo size at the tissue scale, which is coupled to cell position and fate at the cellular scale.
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173
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Self-Organized Nuclear Positioning Synchronizes the Cell Cycle in Drosophila Embryos. Cell 2019; 177:925-941.e17. [PMID: 30982601 DOI: 10.1016/j.cell.2019.03.007] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/16/2018] [Accepted: 03/04/2019] [Indexed: 11/22/2022]
Abstract
The synchronous cleavage divisions of early embryogenesis require coordination of the cell-cycle oscillator, the dynamics of the cytoskeleton, and the cytoplasm. Yet, it remains unclear how spatially restricted biochemical signals are integrated with physical properties of the embryo to generate collective dynamics. Here, we show that synchronization of the cell cycle in Drosophila embryos requires accurate nuclear positioning, which is regulated by the cell-cycle oscillator through cortical contractility and cytoplasmic flows. We demonstrate that biochemical oscillations are initiated by local Cdk1 inactivation and spread through the activity of phosphatase PP1 to generate cortical myosin II gradients. These gradients cause cortical and cytoplasmic flows that control proper nuclear positioning. Perturbations of PP1 activity and optogenetic manipulations of cortical actomyosin disrupt nuclear spreading, resulting in loss of cell-cycle synchrony. We conclude that mitotic synchrony is established by a self-organized mechanism that integrates the cell-cycle oscillator and embryo mechanics.
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174
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Menchero S, Rollan I, Lopez-Izquierdo A, Andreu MJ, Sainz de Aja J, Kang M, Adan J, Benedito R, Rayon T, Hadjantonakis AK, Manzanares M. Transitions in cell potency during early mouse development are driven by Notch. eLife 2019; 8:42930. [PMID: 30958266 PMCID: PMC6486152 DOI: 10.7554/elife.42930] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 04/07/2019] [Indexed: 12/11/2022] Open
Abstract
The Notch signalling pathway plays fundamental roles in diverse developmental processes in metazoans, where it is important in driving cell fate and directing differentiation of various cell types. However, we still have limited knowledge about the role of Notch in early preimplantation stages of mammalian development, or how it interacts with other signalling pathways active at these stages such as Hippo. By using genetic and pharmacological tools in vivo, together with image analysis of single embryos and pluripotent cell culture, we have found that Notch is active from the 4-cell stage. Transcriptomic analysis in single morula identified novel Notch targets, such as early naïve pluripotency markers or transcriptional repressors such as TLE4. Our results reveal a previously undescribed role for Notch in driving transitions during the gradual loss of potency that takes place in the early mouse embryo prior to the first lineage decisions. We start life as a single cell, which immediately begins to divide to form an embryo that will eventually contain all the different kinds of cells found in the adult body. During the first few rounds of cell division, embryonic cells can become any type of adult cells, but also form the placenta, the organ that sustains the embryo while in the womb. As cells keep on dividing, they lose this ability, called potency, and they take on more specific and inflexible roles. The first choice embryonic cells must make is whether to become part of the placenta or part of the future body. These types of decisions are controlled by molecular cascades known as signalling pathways, which relay information from the cells surface to its control centre. There, specific genes get turned on or off in response to an outside signal. Previous research showed that two signalling pathways, Hippo and Notch, help separate placenta cells from those that will form the rest of the body. However, it was not known whether the two pathways worked independently, or if they were overlapping. Menchero et al. therefore wanted to find out when exactly the Notch pathway started to be active, and examine how it helped cells to either become the placenta or part of the future body. Experiments with developing mouse embryos showed that the Notch pathway was activated after the very first two cell divisions, when the embryo consists of only four cells. Genetic manipulations combined with drug treatments that changed the activity of the Notch pathway confirmed that Notch and Hippo acted independently at this stage. Further, larger-scale analysis of gene activity in these embryos also revealed that Notch signalling was working in a previously unknown way: it turned off the genes that maintain potency, pushing the cells to become more specialised. Ultimately, identifying this new mode of action for the Notch pathway in the early embryo may help to understand how the signalling cascade acts in other types of processes. This knowledge could be useful, for example, to push embryonic cells grown in the laboratory towards a desired fate.
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Affiliation(s)
- Sergio Menchero
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Isabel Rollan
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | | | - Maria Jose Andreu
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Julio Sainz de Aja
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Minjung Kang
- Developmental Biology Program, Sloan Kettering Institute, New York, United States
| | - Javier Adan
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Rui Benedito
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Teresa Rayon
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | | | - Miguel Manzanares
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
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175
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Lemke SB, Weidemann T, Cost AL, Grashoff C, Schnorrer F. A small proportion of Talin molecules transmit forces at developing muscle attachments in vivo. PLoS Biol 2019; 17:e3000057. [PMID: 30917109 PMCID: PMC6453563 DOI: 10.1371/journal.pbio.3000057] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 04/08/2019] [Accepted: 03/08/2019] [Indexed: 11/19/2022] Open
Abstract
Cells in developing organisms are subjected to particular mechanical forces that shape tissues and instruct cell fate decisions. How these forces are sensed and transmitted at the molecular level is therefore an important question, one that has mainly been investigated in cultured cells in vitro. Here, we elucidate how mechanical forces are transmitted in an intact organism. We studied Drosophila muscle attachment sites, which experience high mechanical forces during development and require integrin-mediated adhesion for stable attachment to tendons. Therefore, we quantified molecular forces across the essential integrin-binding protein Talin, which links integrin to the actin cytoskeleton. Generating flies expressing 3 Förster resonance energy transfer (FRET)-based Talin tension sensors reporting different force levels between 1 and 11 piconewton (pN) enabled us to quantify physiologically relevant molecular forces. By measuring primary Drosophila muscle cells, we demonstrate that Drosophila Talin experiences mechanical forces in cell culture that are similar to those previously reported for Talin in mammalian cell lines. However, in vivo force measurements at developing flight muscle attachment sites revealed that average forces across Talin are comparatively low and decrease even further while attachments mature and tissue-level tension remains high. Concomitantly, the Talin concentration at attachment sites increases 5-fold as quantified by fluorescence correlation spectroscopy (FCS), suggesting that only a small proportion of Talin molecules are mechanically engaged at any given time. Reducing Talin levels at late stages of muscle development results in muscle–tendon rupture in the adult fly, likely as a result of active muscle contractions. We therefore propose that a large pool of adhesion molecules is required to share high tissue forces. As a result, less than 15% of the molecules experience detectable forces at developing muscle attachment sites at the same time. Our findings define an important new concept of how cells can adapt to changes in tissue mechanics to prevent mechanical failure in vivo. The protein Talin links the transmembrane cell adhesion molecule integrin to the actin cytoskeleton. Quantitative FRET-based force measurements across Talin in vivo reveal that only few Talin molecules are under force during the development of muscle attachment sites. Cells in our body are constantly exposed to mechanical forces, which they need to sense and react to. In previous studies, fluorescent force sensors were developed to demonstrate that individual proteins in adhesion structures of a cell experience forces in the piconewton (pN) range. However, these cells were analyzed in isolation in an artificial plastic or glass environment. Here, we explored forces on adhesion proteins in their natural environment within a developing animal and used the muscle–tendon tissue in the fruit fly Drosophila as a model system. We made genetically modified fly lines with force sensors or controls inserted into the gene that produces the essential adhesion protein Talin. Using these force sensor flies, we found that only a small proportion of all the Talin proteins (<15%) present at developing muscle–tendon attachments experience detectable forces at the same time. Nevertheless, a large amount of Talin is accumulated at these attachments during fly development. We found that this large Talin pool is important to prevent rupture of the muscle–tendon connection in adult flies that produce high muscle forces during flight. In conclusion, we demonstrated that a large pool of Talin proteins is required for stable muscle–tendon attachment, likely with the individual Talin molecules dynamically sharing the mechanical load.
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Affiliation(s)
- Sandra B. Lemke
- Max Planck Institute of Biochemistry, Martinsried, Germany
- * E-mail: (FS); (CG); (SBL)
| | | | - Anna-Lena Cost
- Max Planck Institute of Biochemistry, Martinsried, Germany
- University of Münster, Institute for Molecular Cell Biology, Münster, Germany
| | - Carsten Grashoff
- Max Planck Institute of Biochemistry, Martinsried, Germany
- University of Münster, Institute for Molecular Cell Biology, Münster, Germany
- * E-mail: (FS); (CG); (SBL)
| | - Frank Schnorrer
- Max Planck Institute of Biochemistry, Martinsried, Germany
- Aix Marseille University, CNRS, IBDM, Marseille, France
- * E-mail: (FS); (CG); (SBL)
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176
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Filimonow K, Saiz N, Suwińska A, Wyszomirski T, Grabarek JB, Ferretti E, Piliszek A, Plusa B, Maleszewski M. No evidence of involvement of E-cadherin in cell fate specification or the segregation of Epi and PrE in mouse blastocysts. PLoS One 2019; 14:e0212109. [PMID: 30735538 PMCID: PMC6368326 DOI: 10.1371/journal.pone.0212109] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 01/27/2019] [Indexed: 12/13/2022] Open
Abstract
During preimplantation mouse development stages, emerging pluripotent epiblast (Epi) and extraembryonic primitive endoderm (PrE) cells are first distributed in the blastocyst in a "salt-and-pepper" manner before they segregate into separate layers. As a result of segregation, PrE cells become localised on the surface of the inner cell mass (ICM), and the Epi is enclosed by the PrE on one side and by the trophectoderm on the other. During later development, a subpopulation of PrE cells migrates away from the ICM and forms the parietal endoderm (PE), while cells remaining in contact with the Epi form the visceral endoderm (VE). Here, we asked: what are the mechanisms mediating Epi and PrE cell segregation and the subsequent VE vs PE specification? Differences in cell adhesion have been proposed; however, we demonstrate that the levels of plasma membrane-bound E-cadherin (CDH1, cadherin 1) in Epi and PrE cells only differ after the segregation of these lineages within the ICM. Moreover, manipulating E-cadherin levels did not affect lineage specification or segregation, thus failing to confirm its role during these processes. Rather, we report changes in E-cadherin localisation during later PrE-to-PE transition which are accompanied by the presence of Vimentin and Twist, supporting the hypothesis that an epithelial-to-mesenchymal transition process occurs in the mouse peri-implantation blastocyst.
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Affiliation(s)
- Katarzyna Filimonow
- Department of Embryology, Faculty of Biology, The University of Warsaw, I. Miecznikowa, Warsaw, Poland
- Division of Developmental Biology and Medicine, The University of Manchester, Oxford Road, Manchester, United Kingdom
- Department of Experimental Embryology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Postępu 36a, Jastrzębiec, Poland
| | - Nestor Saiz
- Division of Developmental Biology and Medicine, The University of Manchester, Oxford Road, Manchester, United Kingdom
| | - Aneta Suwińska
- Department of Embryology, Faculty of Biology, The University of Warsaw, I. Miecznikowa, Warsaw, Poland
| | - Tomasz Wyszomirski
- Faculty of Biology, Biological and Chemical Research Centre, The University of Warsaw, Zwirki i Wigury, Warsaw, Poland
| | - Joanna B. Grabarek
- Division of Developmental Biology and Medicine, The University of Manchester, Oxford Road, Manchester, United Kingdom
| | - Elisabetta Ferretti
- The Danish Stem Cell Centre (DanStem), University of Copenhagen, Blegdamsvej, Copenhagen N, Denmark
| | - Anna Piliszek
- Department of Experimental Embryology, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Postępu 36a, Jastrzębiec, Poland
| | - Berenika Plusa
- Division of Developmental Biology and Medicine, The University of Manchester, Oxford Road, Manchester, United Kingdom
- * E-mail: (MM); (BP)
| | - Marek Maleszewski
- Department of Embryology, Faculty of Biology, The University of Warsaw, I. Miecznikowa, Warsaw, Poland
- * E-mail: (MM); (BP)
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177
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De Caluwé J, Tosenberger A, Gonze D, Dupont G. Signalling-modulated gene regulatory networks in early mammalian development. J Theor Biol 2019; 463:56-66. [DOI: 10.1016/j.jtbi.2018.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 10/25/2018] [Accepted: 12/05/2018] [Indexed: 01/18/2023]
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178
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Topal T, Kim BC, Villa-Diaz LG, Deng CX, Takayama S, Krebsbach PH. Rapid translocation of pluripotency-related transcription factors by external uniaxial forces. Integr Biol (Camb) 2019; 11:41-52. [PMID: 30809641 PMCID: PMC6428113 DOI: 10.1093/intbio/zyz003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/22/2019] [Indexed: 11/14/2022]
Abstract
Human embryonic stem cells subjected to a one-time uniaxial stretch for as short as 30-min on a flexible substrate coated with Matrigel experienced rapid and irreversible nuclear-to-cytoplasmic translocation of NANOG and OCT4, but not Sox2. Translocations were directed by intracellular transmission of biophysical signals from cell surface integrins to nuclear CRM1 and were independent of exogenous soluble factors. On E-CADHERIN-coated substrates, presumably with minimal integrin engagement, mechanical strain-induced rapid nuclear-to-cytoplasmic translocation of the three transcription factors. These findings might provide fundamental insights into early developmental processes and may facilitate mechanotransduction-mediated bioengineering approaches to influencing stem cell fate determination.
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Affiliation(s)
- Tuğba Topal
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Byoung Choul Kim
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Division of Nano-Bioengineering, Incheon National University, Incheon, Republic of Korea
| | - Luis G Villa-Diaz
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Sciences, Oakland University, Rochester, MI, USA
| | - Cheri X Deng
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Shuichi Takayama
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory School of Medicine, Atlanta, GA, USA
| | - Paul H Krebsbach
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, USA
- Section of Periodontics, University of California, Los Angeles School of Dentistry, Los Angeles, CA, USA
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179
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Marikawa Y, Alarcon VB. RHOA activity in expanding blastocysts is essential to regulate HIPPO-YAP signaling and to maintain the trophectoderm-specific gene expression program in a ROCK/actin filament-independent manner. Mol Hum Reprod 2019; 25:43-60. [PMID: 30395288 PMCID: PMC6497036 DOI: 10.1093/molehr/gay048] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 11/03/2018] [Indexed: 12/14/2022] Open
Abstract
STUDY QUESTION What molecular signals are required to maintain the functional trophectoderm (TE) during blastocyst expansion of the late stage of preimplantation development? SUMMARY ANSWER The activity of ras homology family member A (RHOA) GTPases is necessary to retain the expanded blastocyst cavity and also to sustain the gene expression program specific to TE. WHAT IS KNOWN ALREADY At the early stages of preimplantation development, the precursor of the TE lineage is generated through the molecular signals that integrate RHOA, RHO-associated coiled-coil containing protein kinase (ROCK), the apicobasal cell polarity, and the HIPPO-Yes-associated protein (YAP) signaling pathway. By contrast, molecular mechanisms regulating the maintenance of the TE characteristics at the later stage, which is crucial for blastocyst hatching and implantation, are scarcely understood. STUDY DESIGN, SIZE, DURATION Expanding mouse blastocysts, obtained from crosses of the F1 (C57BL6 × DBA/2) strain, were exposed to chemical agents that interfere with RHOA, ROCK, or the actin cytoskeleton for up to 8 h, and effects on the blastocyst cavity, HIPPO-YAP signaling, and cell lineage-specific gene expression profiles were examined. PARTICIPANTS/MATERIALS, SETTING, METHODS Mouse embryos at the embryonic stage E3.5 (expanding blastocysts) and E4.5 (fully expanded blastocysts) were treated with RHOA inhibitor (C3 exoenzyme), ROCK inhibitor (Y27632), or actin filament disruptors (cytochalasin B and latrunculin A). The integrity of the blastocyst cavity was evaluated based on the gross morphology. Effects on HIPPO-YAP signaling were assessed based on the presence of nuclearized YAP protein by immunofluorescence staining and the expression of YAP/TEA domain family member (TEAD) target genes by quantitative RT-PCR (qRT-PCR). The impact of these disruptors on cell lineages was evaluated based on expression of the TE-specific and inner cell mass-specific marker genes by qRT-PCR. The integrity of the apicobasal cell polarity was assessed by localization of protein kinase C zeta (PRKCZ; apical) and scribbled planar cell polarity (SCRIB; basal) proteins by immunofluorescence staining. For comparisons, cultured cell lines, NIH/3T3 (mouse fibroblast) and P19C5 (mouse embryonal carcinoma), were also treated with RHOA inhibitor, ROCK inhibitor, and actin filament disruptors for up to 8 h, and effects on HIPPO-YAP signaling were assessed based on expression of YAP/TEAD target genes by qRT-PCR. Each experiment was repeated using three independent batches of embryos (n = 40-80 per batch) or cell collections. Statistical analyses of data were performed, using one-way ANOVA and two-sample t-test. MAIN RESULTS AND THE ROLE OF CHANCE Inhibition of RHOA deflated the cavity, diminished nuclear YAP (P < 0.01), and down-regulated the YAP/TEAD target and TE-specific marker genes in both E3.5 and E4.5 blastocysts (P < 0.05), indicating that the maintenance of the key TE characteristics is dependent on RHOA activity. However, inhibition of ROCK or disruption of actin filament only deflated the blastocyst cavity, but did not alter HIPPO-YAP signaling or lineage-specific gene expressions, suggesting that the action of RHOA to sustain the TE-specific gene expression program is not mediated by ROCK or the actomyosin cytoskeleton. By contrast, ROCK inhibitor and actin filament disruptors diminished YAP/TEAD target gene expressions in cultured cells to a greater extent than RHOA inhibitor, implicating that the regulation of HIPPO-YAP signaling in expanding blastocysts is distinctly different from that in the cell lines. Furthermore, the apicobasal cell polarity proteins in the expanding blastocyst were mislocalized by ROCK inhibition but not by RHOA inhibition, indicating that cell polarity is not linked to regulation of HIPPO-YAP signaling. Taken together, our study suggests that RHOA activity is essential to maintain the TE lineage in the expanding blastocyst and it regulates HIPPO-YAP signaling and the lineage-specific gene expression program through mechanisms that are independent of ROCK or actomyosin cytoskeleton. LARGE-SCALE DATA Not applicable. LIMITATIONS, REASONS FOR CAUTION This study was conducted using one species, the mouse. Direct translation of the experiments and findings to human fertility preservation and ART requires further investigations. WIDER IMPLICATIONS OF THE FINDINGS The elucidation of the mechanisms of TE formation is highly pertinent to fertility preservation in women. Our findings may raise awareness among providers of ART that the TE is sensitive to disturbance even in the late stage of blastocyst expansion and that rational approaches should be devised to avoid conditions that may impair the TE and its function. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by grants from the Ingeborg v.F. McKee Fund of the Hawaii Community Foundation (16ADVC-78882 to V.B.A.), and the National Institutes of Health (P20 GM103457 and R03 HD088839 to V.B.A.). The authors have no conflict of interest to declare.
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Affiliation(s)
- Yusuke Marikawa
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Vernadeth B Alarcon
- Institute for Biogenesis Research, Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA
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180
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Revell C, Blumenfeld R, Chalut KJ. Force-based three-dimensional model predicts mechanical drivers of cell sorting. Proc Biol Sci 2019; 286:20182495. [PMID: 30963946 PMCID: PMC6364585 DOI: 10.1098/rspb.2018.2495] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/03/2019] [Indexed: 01/22/2023] Open
Abstract
Many biological processes, including tissue morphogenesis, are driven by cell sorting. However, the primary mechanical drivers of sorting in multicellular aggregates (MCAs) remain controversial, in part because there is no appropriate computational model to probe mechanical interactions between cells. To address this important issue, we developed a three-dimensional, local force-based simulation based on the subcellular element method. In our method, cells are modelled as collections of locally interacting force-bearing elements. We use the method to investigate the effects of tension and cell-cell adhesion on MCA sorting. We predict a minimum level of adhesion to produce inside-out sorting of two cell types, which is in excellent agreement with observations in several developmental systems. We also predict the level of tension asymmetry needed for robust sorting. The generality and flexibility of the method make it applicable to tissue self-organization in a myriad of other biological processes, such as tumorigenesis and embryogenesis.
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Affiliation(s)
- Christopher Revell
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
| | - Raphael Blumenfeld
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
- Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK
| | - Kevin J. Chalut
- Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
- Wellcome Trust/Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, UK
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181
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Advances in Micropipette Aspiration: Applications in Cell Biomechanics, Models, and Extended Studies. Biophys J 2019; 116:587-594. [PMID: 30683304 DOI: 10.1016/j.bpj.2019.01.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/29/2018] [Accepted: 01/02/2019] [Indexed: 12/31/2022] Open
Abstract
With five decades of sustained application, micropipette aspiration has enabled a wide range of biomechanical studies in the field of cell mechanics. Here, we provide an update on the use of the technique, with a focus on recent developments in the analysis of the experiments, innovative microaspiration-based approaches, and applications in a broad variety of cell types. We first recapitulate experimental variations of the technique. We then discuss analysis models focusing on important limitations of widely used biomechanical models, which underpin the urge to adopt the appropriate ones to avoid misleading conclusions. The possibilities of performing different studies on the same cell are also considered.
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182
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Frum T, Ralston A. Visualizing HIPPO Signaling Components in Mouse Early Embryonic Development. Methods Mol Biol 2019; 1893:335-352. [PMID: 30565145 DOI: 10.1007/978-1-4939-8910-2_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The HIPPO signaling pathway plays an early and essential role in mammalian embryogenesis. The earliest known roles for HIPPO signaling during mouse development include segregating fetal and extraembryonic lineages and establishing the pluripotent progenitors of embryonic stem (ES) cells. In the mouse early embryo, HIPPO signaling responds to multiple cell biological inputs, including cell polarization, cytoskeleton, and cell environment, to influence gene expression and the first cell fate decisions in development. Methods to monitor and manipulate HIPPO signaling in the mouse early embryo are fundamental to discovering mechanisms regulating pluripotency in vivo, but properties of the early embryo, such as small cell number and spherical architecture, pose unique challenges for signaling pathway analysis. Here, we share approaches for visualizing HIPPO signaling in mouse early embryos. In addition, these methods can be applied to visualize HIPPO signaling in other spherical or cystic structures comprised of relatively few cells, such as organoids, or for the examination of other signaling pathways in these contexts.
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Affiliation(s)
- Tristan Frum
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Amy Ralston
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
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183
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Frum T, Murphy TM, Ralston A. HIPPO signaling resolves embryonic cell fate conflicts during establishment of pluripotency in vivo. eLife 2018; 7:42298. [PMID: 30526858 PMCID: PMC6289571 DOI: 10.7554/elife.42298] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/12/2018] [Indexed: 01/03/2023] Open
Abstract
During mammalian development, the challenge for the embryo is to override intrinsic cellular plasticity to drive cells to distinct fates. Here, we unveil novel roles for the HIPPO signaling pathway in controlling cell positioning and expression of Sox2, the first marker of pluripotency in the mouse early embryo. We show that maternal and zygotic YAP1 and WWTR1 repress Sox2 while promoting expression of the trophectoderm gene Cdx2 in parallel. Yet, Sox2 is more sensitive than Cdx2 to Yap1/Wwtr1 dosage, leading cells to a state of conflicted cell fate when YAP1/WWTR1 activity is moderate. Remarkably, HIPPO signaling activity resolves conflicted cell fate by repositioning cells to the interior of the embryo, independent of its role in regulating Sox2 expression. Rather, HIPPO antagonizes apical localization of Par complex components PARD6B and aPKC. Thus, negative feedback between HIPPO and Par complex components ensure robust lineage segregation. As an embryo develops, its cells divide, grow and migrate in specific patterns to build an organized collection of cells that go on to form our tissues and organs. One of the first steps – well before the embryo has implanted into the womb – is to allocate cells to make part of the placenta. Once this process is complete, the remaining cells continue building the organism. These cells are pluripotent, meaning they can develop into any part of the body. Scientists think that the embryo manages to sort ‘placenta cells’ from pluripotent ones with the help of certain proteins, which the mother has packaged into her eggs. To investigate this further, Frum et al. used genetic tools to track a specific gene called Sox2 that identifies pluripotent cells as soon as they are formed in mouse embryos. The experiments revealed that the mother places two closely related proteins known as YAP1 and WWTR1 within each egg, which help to make placenta cells different from pluripotent cells. Moreover, both proteins enable the embryo to segregate these two cell types to two different locations: placenta cells are moved to the outer layer of the embryo, while pluripotent cells are moved to the inside. Current technologies allow researchers to create pluripotent cells in the laboratory. But these approaches often result in error, failing to replicate the embryo’s natural ability. By studying how embryos form and arrange pluripotent cells, scientists hope to advance stem cell technology (which emerge from pluripotent cells). This may help to find new ways to heal damaged tissues and organs, or to treat or even prevent many diseases.
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Affiliation(s)
- Tristan Frum
- Department of Biochemistry and Molecular Biology, Michigan State University, Michigan, United States
| | - Tayler M Murphy
- Genetics Graduate Program, Michigan State University, Michigan, United States.,Reproductive and Developmental Biology Training Program, Michigan State University, Michigan, United States
| | - Amy Ralston
- Department of Biochemistry and Molecular Biology, Michigan State University, Michigan, United States.,Genetics Graduate Program, Michigan State University, Michigan, United States.,Reproductive and Developmental Biology Training Program, Michigan State University, Michigan, United States
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184
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Merle T, Farge E. Trans-scale mechanotransductive cascade of biochemical and biomechanical patterning in embryonic development: the light side of the force. Curr Opin Cell Biol 2018; 55:111-118. [DOI: 10.1016/j.ceb.2018.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 06/25/2018] [Accepted: 07/09/2018] [Indexed: 01/06/2023]
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185
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Perestrelo T, Correia M, Ramalho-Santos J, Wirtz D. Metabolic and Mechanical Cues Regulating Pluripotent Stem Cell Fate. Trends Cell Biol 2018; 28:1014-1029. [DOI: 10.1016/j.tcb.2018.09.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/30/2018] [Accepted: 09/25/2018] [Indexed: 02/07/2023]
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186
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Abstract
Establishing the different lineages of the early mammalian embryo takes place over several days and several rounds of cell divisions from the fertilized egg. The resulting blastocyst contains the pluripotent cells of the epiblast, from which embryonic stem cells can be derived, as well as the extraembryonic lineages required for a mammalian embryo to survive in the uterine environment. The dynamics of the cellular and genetic interactions controlling the initiation and maintenance of these lineages in the mouse embryo are increasingly well understood through application of the tools of single-cell genomics, gene editing, and in vivo imaging. Exploring the similarities and differences between mouse and human development will be essential for translation of these findings into new insights into human biology, derivation of stem cells, and improvements in fertility treatments.
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Affiliation(s)
- Janet Rossant
- Program in Stem Cell and Developmental Biology, Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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187
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Abstract
Hippo signaling is an evolutionarily conserved network that has a central role in regulating cell proliferation and cell fate to control organ growth and regeneration. It promotes activation of the LATS kinases, which control gene expression by inhibiting the activity of the transcriptional coactivator proteins YAP and TAZ in mammals and Yorkie in Drosophila. Diverse upstream inputs, including both biochemical cues and biomechanical cues, regulate Hippo signaling and enable it to have a key role as a sensor of cells' physical environment and an integrator of growth control signals. Several components of this pathway localize to cell-cell junctions and contribute to regulation of Hippo signaling by cell polarity, cell contacts, and the cytoskeleton. Downregulation of Hippo signaling promotes uncontrolled cell proliferation, impairs differentiation, and is associated with cancer. We review the current understanding of Hippo signaling and highlight progress in the elucidation of its regulatory mechanisms and biological functions.
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Affiliation(s)
- Jyoti R Misra
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854, USA;
| | - Kenneth D Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854, USA;
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188
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Xavier da Silveira Dos Santos A, Liberali P. From single cells to tissue self-organization. FEBS J 2018; 286:1495-1513. [PMID: 30390414 PMCID: PMC6519261 DOI: 10.1111/febs.14694] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/10/2018] [Accepted: 11/02/2018] [Indexed: 12/16/2022]
Abstract
Self-organization is a process by which interacting cells organize and arrange themselves in higher order structures and patterns. To achieve this, cells must have molecular mechanisms to sense their complex local environment and interpret it to respond accordingly. A combination of cell-intrinsic and cell-extrinsic cues are decoded by the single cells dictating their behaviour, their differentiation and symmetry-breaking potential driving development, tissue remodeling and regenerative processes. A unifying property of these self-organized pattern-forming systems is the importance of fluctuations, cell-to-cell variability, or noise. Cell-to-cell variability is an inherent and emergent property of populations of cells that maximize the population performance instead of the individual cell, providing tissues the flexibility to develop and maintain homeostasis in diverse environments. In this review, we will explore the role of self-organization and cell-to-cell variability as fundamental properties of multicellularity-and the requisite of single-cell resolution for its understanding. Moreover, we will analyze how single cells generate emergent multicellular dynamics observed at the tissue level 'travelling' across different scales: spatial, temporal and functional.
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Affiliation(s)
| | - Prisca Liberali
- Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland.,University of Basel, Switzerland
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189
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Characterizing Inner Pressure and Stiffness of Trophoblast and Inner Cell Mass of Blastocysts. Biophys J 2018; 115:2443-2450. [PMID: 30509858 DOI: 10.1016/j.bpj.2018.11.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/23/2018] [Accepted: 11/05/2018] [Indexed: 12/14/2022] Open
Abstract
It has long been recognized that mechanical forces underlie mammalian embryonic shape changes. Before gastrulation, the blastocyst embryo undergoes significant shape changes, namely, the blastocyst cavity emerges and expands, and the inner cell mass (ICM) forms and changes in shape. The embryo's inner pressure has been hypothesized to be the driving mechanical input that causes the expansion of the blastocyst cavity and the shape changes of the ICM. However, how the inner pressure and the mechanics of the trophoblast and the ICM change during development is unknown because of the lack of a suitable tool for quantitative characterization. This work presents a laser-assisted magnetic tweezer technique for measuring the inner pressure and Young's modulus of the trophoblast and ICM of the blastocyst-stage mouse embryo. The results quantitatively showed that the inner pressure and Young's modulus of the trophoblast and ICM all increase during progression of mouse blastocysts, providing useful data for understanding how mechanical factors are physiologically integrated with other cues to direct embryo development.
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190
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Bredov D, Volodyaev I. Increasing complexity: Mechanical guidance and feedback loops as a basis for self-organization in morphogenesis. Biosystems 2018; 173:133-156. [PMID: 30292533 DOI: 10.1016/j.biosystems.2018.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 10/28/2022]
Abstract
The article is devoted to physical views on embryo development as a combination of structurally stable dynamics and symmetry-breaking events in the general process of self-organization. The first corresponds to the deterministic aspect of embryo development. The second type of processes is associated with sudden increase of variability in the periods of symmetry-breaking, which manifests unstable dynamics. The biological basis under these considerations includes chemokinetics (a system of inductors, repressors, and interaction with their next surrounding) and morphomechanics (i.e. mechanotransduction, mechanosensing, and related feedback loops). Although the latter research area is evolving rapidly, up to this time the role of mechanical properties of embryonic tissues and mechano-dependent processes in them are integrated in the general picture of embryo development to a lesser extent than biochemical signaling. For this reason, the present article is mostly devoted to experimental data on morphomechanics in the process of embryo development, also including analysis of its limitations and possible contradictions. The general system of feedback-loops and system dynamics delineated in this review is in large part a repetition of the views of Lev Beloussov, who was one of the founders of the whole areas of morphomechanics and morphodynamics, and to whose memory this article is dedicated.
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Affiliation(s)
- Denis Bredov
- Laboratory of Developmental biophysics, Department of Embryology, Faculty of Biology, Moscow State University, Moscow, 119234, Russia
| | - Ilya Volodyaev
- Laboratory of Developmental biophysics, Department of Embryology, Faculty of Biology, Moscow State University, Moscow, 119234, Russia.
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191
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Plusa B, Hadjantonakis AK. (De)constructing the blastocyst: Lessons in self-organization from the mouse. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.coisb.2018.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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192
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Blin G, Wisniewski D, Picart C, Thery M, Puceat M, Lowell S. Geometrical confinement controls the asymmetric patterning of brachyury in cultures of pluripotent cells. Development 2018; 145:dev166025. [PMID: 30115626 PMCID: PMC6176930 DOI: 10.1242/dev.166025] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 07/30/2018] [Indexed: 01/02/2023]
Abstract
Diffusible signals are known to orchestrate patterning during embryogenesis, yet diffusion is sensitive to noise. The fact that embryogenesis is remarkably robust suggests that additional layers of regulation reinforce patterning. Here, we demonstrate that geometrical confinement orchestrates the spatial organisation of initially randomly positioned subpopulations of spontaneously differentiating mouse embryonic stem cells. We use micropatterning in combination with pharmacological manipulations and quantitative imaging to dissociate the multiple effects of geometry. We show that the positioning of a pre-streak-like population marked by brachyury (T) is decoupled from the size of its population, and that breaking radial symmetry of patterns imposes polarised patterning. We provide evidence for a model in which the overall level of diffusible signals together with the history of the cell culture define the number of T+ cells, whereas geometrical constraints guide patterning in a multi-step process involving a differential response of the cells to multicellular spatial organisation. Our work provides a framework for investigating robustness of patterning and provides insights into how to guide symmetry-breaking events in aggregates of pluripotent cells.
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Affiliation(s)
- Guillaume Blin
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Darren Wisniewski
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Catherine Picart
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH16 4UU, UK
| | - Manuel Thery
- Univ. Grenoble-Alpes, CEA, CNRS, INRA, Biosciences and Biotechnology Institute of Grenoble, Laboratoire de Physiologie Cellulaire and Végétale, UMR5168, CytoMorpho Lab, 38054 Grenoble, France
- Univ. Paris Diderot, CEA, INSERM, Hôpital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, CytoMorpho Lab, 75010 Paris, France
| | - Michel Puceat
- INSERM U1251, Université Aix-Marseille, MMG, 13885 Marseille, France
| | - Sally Lowell
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, EH16 4UU, UK
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193
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Abstract
We present an overview of symmetry breaking in early mammalian development as a continuous process from compaction to specification of the body axes. While earlier studies have focused on individual symmetry-breaking events, recent advances enable us to explore progressive symmetry breaking during early mammalian development. Although we primarily discuss embryonic development of the mouse, as it is the best-studied mammalian model system to date, we also highlight the shared and distinct aspects between different mammalian species. Finally, we discuss how insights gained from studying mammalian development can be generalized in light of self-organization principles. With this review, we hope to highlight new perspectives in studying symmetry breaking and self-organization in multicellular systems.
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Affiliation(s)
- Hui Ting Zhang
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany;
| | - Takashi Hiiragi
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany;
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194
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Bornens M. Cell polarity: having and making sense of direction-on the evolutionary significance of the primary cilium/centrosome organ in Metazoa. Open Biol 2018; 8:180052. [PMID: 30068565 PMCID: PMC6119866 DOI: 10.1098/rsob.180052] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/05/2018] [Indexed: 12/13/2022] Open
Abstract
Cell-autonomous polarity in Metazoans is evolutionarily conserved. I assume that permanent polarity in unicellular eukaryotes is required for cell motion and sensory reception, integration of these two activities being an evolutionarily constrained function. Metazoans are unique in making cohesive multicellular organisms through complete cell divisions. They evolved a primary cilium/centrosome (PC/C) organ, ensuring similar functions to the basal body/flagellum of unicellular eukaryotes, but in different cells, or in the same cell at different moments. The possibility that this innovation contributed to the evolution of individuality, in being instrumental in the early specification of the germ line during development, is further discussed. Then, using the example of highly regenerative organisms like planarians, which have lost PC/C organ in dividing cells, I discuss the possibility that part of the remodelling necessary to reach a new higher-level unit of selection in multi-cellular organisms has been triggered by conflicts among individual cell polarities to reach an organismic polarity. Finally, I briefly consider organisms with a sensorimotor organ like the brain that requires exceedingly elongated polarized cells for its activity. I conclude that beyond critical consequences for embryo development, the conservation of cell-autonomous polarity in Metazoans had far-reaching implications for the evolution of individuality.
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Affiliation(s)
- Michel Bornens
- Institut Curie, PSL Research University, CNRS - UMR 144, 75005 Paris, France
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195
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Chan CJ, Heisenberg CP, Hiiragi T. Coordination of Morphogenesis and Cell-Fate Specification in Development. Curr Biol 2018; 27:R1024-R1035. [PMID: 28950087 DOI: 10.1016/j.cub.2017.07.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
During animal development, cell-fate-specific changes in gene expression can modify the material properties of a tissue and drive tissue morphogenesis. While mechanistic insights into the genetic control of tissue-shaping events are beginning to emerge, how tissue morphogenesis and mechanics can reciprocally impact cell-fate specification remains relatively unexplored. Here we review recent findings reporting how multicellular morphogenetic events and their underlying mechanical forces can feed back into gene regulatory pathways to specify cell fate. We further discuss emerging techniques that allow for the direct measurement and manipulation of mechanical signals in vivo, offering unprecedented access to study mechanotransduction during development. Examination of the mechanical control of cell fate during tissue morphogenesis will pave the way to an integrated understanding of the design principles that underlie robust tissue patterning in embryonic development.
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Affiliation(s)
- Chii J Chan
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | | | - Takashi Hiiragi
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
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196
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Pfeffer PL. Building Principles for Constructing a Mammalian Blastocyst Embryo. BIOLOGY 2018; 7:biology7030041. [PMID: 30041494 PMCID: PMC6164496 DOI: 10.3390/biology7030041] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/16/2022]
Abstract
The self-organisation of a fertilised egg to form a blastocyst structure, which consists of three distinct cell lineages (trophoblast, epiblast and hypoblast) arranged around an off-centre cavity, is unique to mammals. While the starting point (the zygote) and endpoint (the blastocyst) are similar in all mammals, the intervening events have diverged. This review examines and compares the descriptive and functional data surrounding embryonic gene activation, symmetry-breaking, first and second lineage establishment, and fate commitment in a wide range of mammalian orders. The exquisite detail known from mouse embryogenesis, embryonic stem cell studies and the wealth of recent single cell transcriptomic experiments are used to highlight the building principles underlying early mammalian embryonic development.
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Affiliation(s)
- Peter L Pfeffer
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand.
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197
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Abstract
Precisely controlled cell deformations are key to cell migration, division and tissue morphogenesis, and have been implicated in cell differentiation during development, as well as cancer progression. In animal cells, shape changes are primarily driven by the cellular cortex, a thin actomyosin network that lies directly underneath the plasma membrane. Myosin-generated forces create tension in the cortical network, and gradients in tension lead to cellular deformations. Recent studies have provided important insight into the molecular control of cortical tension by progressively unveiling cortex composition and organization. In this Cell Science at a Glance article and the accompanying poster, we review our current understanding of cortex composition and architecture. We then discuss how the microscopic properties of the cortex control cortical tension. While many open questions remain, it is now clear that cortical tension can be modulated through both cortex composition and organization, providing multiple levels of regulation for this key cellular property during cell and tissue morphogenesis. Summary: A summary of the composition, architecture, mechanics and function of the cellular actin cortex, which determines the shape of animal cells, and, thus, provides the foundation for cell and tissue morphogenesis.
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Affiliation(s)
- Priyamvada Chugh
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK .,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Ewa K Paluch
- MRC Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK .,Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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198
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Kim EJY, Korotkevich E, Hiiragi T. Coordination of Cell Polarity, Mechanics and Fate in Tissue Self-organization. Trends Cell Biol 2018; 28:541-550. [DOI: 10.1016/j.tcb.2018.02.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/20/2018] [Accepted: 02/20/2018] [Indexed: 02/06/2023]
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White MD, Zenker J, Bissiere S, Plachta N. Instructions for Assembling the Early Mammalian Embryo. Dev Cell 2018; 45:667-679. [DOI: 10.1016/j.devcel.2018.05.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 01/23/2018] [Accepted: 05/10/2018] [Indexed: 12/15/2022]
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Wickström SA, Niessen CM. Cell adhesion and mechanics as drivers of tissue organization and differentiation: local cues for large scale organization. Curr Opin Cell Biol 2018; 54:89-97. [PMID: 29864721 DOI: 10.1016/j.ceb.2018.05.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/09/2018] [Accepted: 05/08/2018] [Indexed: 02/07/2023]
Abstract
Biological patterns emerge through specialization of genetically identical cells to take up distinct fates according to their position within the organism. How initial symmetry is broken to give rise to these patterns remains an intriguing open question. Several theories of patterning have been proposed, most prominently Turing's reaction-diffusion model of a slowly diffusing activator and a fast diffusing inhibitor generating periodic patterns. Although these reaction-diffusion systems can generate diverse patterns, it is becoming increasingly evident that cell shape and tension anisotropies, mediated via cell-cell and/or cell-matrix contacts, also facilitate symmetry breaking and subsequent self-organized tissue patterning. This review will highlight recent studies that implicate local changes in adhesion and/or tension as key drivers of cell rearrangements. We will also discuss recent studies on the role of cadherin and integrin adhesive receptors in mediating and responding to local tissue tension asymmetries to coordinate cell fate, position and behavior essential for tissue self-organization and maintenance.
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Affiliation(s)
- Sara A Wickström
- Helsinki Institute of Life Science, Biomedicum Helsinki, University of Helsinki, FI-00014 Helsinki, Finland; Wihuri Research Institute, Biomedicum Helsinki, University of Helsinki, FI-00014 Helsinki, Finland; Paul Gerson Unna Group "Skin Homeostasis and Ageing" Max Planck Institute for Biology of Ageing, Cologne, Germany; Cologne Excellence Cluster on Stress Responses in Aging-associated Diseases (CECAD), Germany.
| | - Carien M Niessen
- Department of Dermatology, Cologne Excellence Cluster on Stress Responses in Aging-associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
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