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Yoshida K, Hayashi S. Epidermal growth factor receptor signaling protects epithelia from morphogenetic instability and tissue damage in Drosophila. Development 2023; 150:297057. [PMID: 36897356 PMCID: PMC10108703 DOI: 10.1242/dev.201231] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 02/09/2023] [Indexed: 03/11/2023]
Abstract
Dying cells in the epithelia communicate with neighboring cells to initiate coordinated cell removal to maintain epithelial integrity. Naturally occurring apoptotic cells are mostly extruded basally and engulfed by macrophages. Here, we have investigated the role of Epidermal growth factor (EGF) receptor (EGFR) signaling in the maintenance of epithelial homeostasis. In Drosophila embryos, epithelial tissues undergoing groove formation preferentially enhanced extracellular signal-regulated kinase (ERK) signaling. In EGFR mutant embryos at stage 11, sporadic apical cell extrusion in the head initiates a cascade of apical extrusions of apoptotic and non-apoptotic cells that sweeps the entire ventral body wall. Here, we show that this process is apoptosis dependent, and clustered apoptosis, groove formation, and wounding sensitize EGFR mutant epithelia to initiate massive tissue disintegration. We further show that tissue detachment from the vitelline membrane, which frequently occurs during morphogenetic processes, is a key trigger for the EGFR mutant phenotype. These findings indicate that, in addition to cell survival, EGFR plays a role in maintaining epithelial integrity, which is essential for protecting tissues from transient instability caused by morphogenetic movement and damage.
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Affiliation(s)
- Kentaro Yoshida
- Laboratory for Morphogenetic Signaling, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan
| | - Shigeo Hayashi
- Laboratory for Morphogenetic Signaling, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan
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2
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Cells into tubes: Molecular and physical principles underlying lumen formation in tubular organs. Curr Top Dev Biol 2020; 143:37-74. [PMID: 33820625 DOI: 10.1016/bs.ctdb.2020.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tubular networks, such as the vascular and respiratory systems, transport liquids and gases in multicellular organisms. The basic units of these organs are tubes formed by single or multiple cells enclosing a luminal cavity. The formation and maintenance of correctly sized and shaped lumina are fundamental steps in organogenesis and are essential for organismal homeostasis. Therefore, understanding how cells generate, shape and maintain lumina is crucial for understanding normal organogenesis as well as the basis of pathological conditions. Lumen formation involves polarized membrane trafficking, cytoskeletal dynamics, and the influence of intracellular as well as extracellular mechanical forces, such as cortical tension, luminal pressure or blood flow. Various tissue culture and in vivo model systems, ranging from MDCK cell spheroids to tubular organs in worms, flies, fish, and mice, have provided many insights into the molecular and cellular mechanisms underlying lumenogenesis and revealed key factors that regulate the size and shape of cellular tubes. Moreover, the development of new experimental and imaging approaches enabled quantitative analyses of intracellular dynamics and allowed to assess the roles of cellular and tissue mechanics during tubulogenesis. However, how intracellular processes are coordinated and regulated across scales of biological organization to generate properly sized and shaped tubes is only beginning to be understood. Here, we review recent insights into the molecular, cellular and physical mechanisms underlying lumen formation during organogenesis. We discuss how these mechanisms control lumen formation in various model systems, with a special focus on the morphogenesis of tubular organs in Drosophila.
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3
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Chen T, Guo Y, Shan J, Zhang J, Shen X, Guo J, Liu XM. Vector Analysis of Cytoskeletal Structural Tension and the Mechanisms that Underpin Spectrin-Related Forces in Pyroptosis. Antioxid Redox Signal 2019; 30:1503-1520. [PMID: 29669427 DOI: 10.1089/ars.2017.7366] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Aims: Pyroptotic cells are characterized by plasma swelling, membrane blebbing, and disintegration of the cell membrane mediated by spectrin-based membrane skeleton and intercellular competitive tension activities. The spectrin-based membrane skeleton is involved in membrane organization through the regulation of intercellular tension. Using genetically encoded tension sensors to attain noninvasive force measurements in structural proteins, we investigated how cytoskeletal structural tension influences changes in plasma morphology during pyroptosis and the regulatory mechanism of cytoskeletal structural tension that underpins pyroptosis. Results: The results indicate that increasing spectrin tension is caused by osmotic swelling. Hightened tension of spectrin was closely associated with the shrink tension transmitted synergistically by microfilaments (MFs) and microtubules (MTs). However, the increment of spectrin tension in pyroptotic cells was controlled antagonistically by MF and MT forces. Different from MF tension, outward MT forces participated in the formation of membrane blebs. Spectrin tension caused by inward MF forces resisted pyroptosis swelling. Stabilization of MF and MT structure had little influence on intracellular tension and pyroptosis deformation. Pyroptosis-induced cytoskeletal structural tension was highly dependent on calcium signaling and reactive oxygen species generation. Blocking of membrane pores, nonselective ion flux, or elimination of caspase-1 cleavage resulted in the remission of structural forces associated with pyroptosis failure. Innovation and Conclusions: The data suggest that subcellular tension, in terms of magnitude and vector, is integral to pyroptosis through the mediation of swelling and blebbing and the elimination of structural tension, especially MT forces, may result in pyroptosis inhibition.
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Affiliation(s)
- Tingting Chen
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China.,State Key Laboratory Cultivation Base for TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Yichen Guo
- Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.,Department of Biomedical Engineering, University of Alabama at Birmingham (UAB), Birmingham, Alabama
| | - Jinjun Shan
- Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Jiarui Zhang
- State Key Laboratory Cultivation Base for TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.,Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Xu Shen
- State Key Laboratory Cultivation Base for TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.,Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Jun Guo
- Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, People's Republic of China.,State Key Laboratory Cultivation Base for TCM Quality and Efficacy, School of Medicine and Life Science, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.,Key Laboratory of Drug Target and Drug for Degenerative Disease, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China.,Jiangsu Key Laboratory of Pediatric Respiratory Disease, Institute of Pediatrics, Nanjing University of Chinese Medicine, Nanjing, People's Republic of China
| | - Xiaoguang Margaret Liu
- Department of Biomedical Engineering, University of Alabama at Birmingham (UAB), Birmingham, Alabama
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4
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Kotini MP, Mäe MA, Belting HG, Betsholtz C, Affolter M. Sprouting and anastomosis in the Drosophila trachea and the vertebrate vasculature: Similarities and differences in cell behaviour. Vascul Pharmacol 2019; 112:8-16. [DOI: 10.1016/j.vph.2018.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/21/2018] [Accepted: 11/02/2018] [Indexed: 01/25/2023]
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5
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Best BT. Single-cell branching morphogenesis in the Drosophila trachea. Dev Biol 2018; 451:5-15. [PMID: 30529233 DOI: 10.1016/j.ydbio.2018.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 11/23/2018] [Accepted: 12/01/2018] [Indexed: 12/20/2022]
Abstract
The terminal cells of the tracheal epithelium in Drosophila melanogaster are one of the few known cell types that undergo subcellular morphogenesis to achieve a stable, branched shape. During the animal's larval stages, the cells repeatedly sprout new cytoplasmic processes. These grow very long, wrapping around target tissues to which the terminal cells adhere, and are hollowed by a gas-filled subcellular tube for oxygen delivery. Our understanding of this ramification process remains rudimentary. This review aims to provide a comprehensive summary of studies on terminal cells to date, and attempts to extrapolate how terminal branches might be formed based on the known genetic and molecular components. Next to this cell-intrinsic branching mechanism, we examine the extrinsic regulation of terminal branching by the target tissue and the animal's environment. Finally, we assess the degree of similarity between the patterns established by the branching programs of terminal cells and other branched cells and tissues from a mathematical and conceptual point of view.
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Affiliation(s)
- Benedikt T Best
- Director's Research Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstr. 1, 69117 Heidelberg, Germany; Collaboration for Joint PhD degree from EMBL and Heidelberg University, Faculty of Biosciences, Germany
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6
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Development and Function of the Drosophila Tracheal System. Genetics 2018; 209:367-380. [PMID: 29844090 DOI: 10.1534/genetics.117.300167] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/12/2018] [Indexed: 12/14/2022] Open
Abstract
The tracheal system of insects is a network of epithelial tubules that functions as a respiratory organ to supply oxygen to various target organs. Target-derived signaling inputs regulate stereotyped modes of cell specification, branching morphogenesis, and collective cell migration in the embryonic stage. In the postembryonic stages, the same set of signaling pathways controls highly plastic regulation of size increase and pattern elaboration during larval stages, and cell proliferation and reprograming during metamorphosis. Tracheal tube morphogenesis is also regulated by physicochemical interaction of the cell and apical extracellular matrix to regulate optimal geometry suitable for air flow. The trachea system senses both the external oxygen level and the metabolic activity of internal organs, and helps organismal adaptation to changes in environmental oxygen level. Cellular and molecular mechanisms underlying the high plasticity of tracheal development and physiology uncovered through research on Drosophila are discussed.
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14-3-3εa directs the pulsatile transport of basal factors toward the apical domain for lumen growth in tubulogenesis. Proc Natl Acad Sci U S A 2018; 115:E8873-E8881. [PMID: 30158171 PMCID: PMC6156656 DOI: 10.1073/pnas.1808756115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Ascidians have become a powerful model system in which to uncover basic mechanisms that govern body plan specification and elaboration. In particular, the ascidian notochord is a highly tractable model for tubulogenesis. Here, we use chemical genetics to identify roles for 14-3-3εa, and its binding partner ezrin/radixin/moesin (ERM), in tubulogenesis. Combining genetic and chemical perturbations with live cell imaging, we present evidence that 14-3-3εa–ERM interactions are required for tubulogenesis and that they act by promoting a directed cytoplasmic flow, previously uncharacterized, which carries lumen-associated components from the basal domain to the apical domain to feed lumen growth. Because many core components of this system are highly conserved, these results have broad implications for tubulogenesis in many other contexts. The Ciona notochord has emerged as a simple and tractable in vivo model for tubulogenesis. Here, using a chemical genetics approach, we identified UTKO1 as a selective small molecule inhibitor of notochord tubulogenesis. We identified 14-3-3εa protein as a direct binding partner of UTKO1 and showed that 14-3-3εa knockdown leads to failure of notochord tubulogenesis. We found that UTKO1 prevents 14-3-3εa from interacting with ezrin/radixin/moesin (ERM), which is required for notochord tubulogenesis, suggesting that interactions between 14-3-3εa and ERM play a key role in regulating the early steps of tubulogenesis. Using live imaging, we found that, as lumens begin to open between neighboring cells, 14-3-3εa and ERM are highly colocalized at the basal cortex where they undergo cycles of accumulation and disappearance. Interestingly, the disappearance of 14-3-3εa and ERM during each cycle is tightly correlated with a transient flow of 14-3-3εa, ERM, myosin II, and other cytoplasmic elements from the basal surface toward the lumen-facing apical domain, which is often accompanied by visible changes in lumen architecture. Both pulsatile flow and lumen formation are abolished in larvae treated with UTKO1, in larvae depleted of either 14-3-3εa or ERM, or in larvae expressing a truncated form of 14-3-3εa that lacks the ability to interact with ERM. These results suggest that 14-3-3εa and ERM interact at the basal cortex to direct pulsatile basal accumulation and basal–apical transport of factors that are essential for lumen formation. We propose that similar mechanisms may underlie or may contribute to lumen formation in tubulogenesis in other systems.
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8
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Ogura Y, Wen FL, Sami MM, Shibata T, Hayashi S. A Switch-like Activation Relay of EGFR-ERK Signaling Regulates a Wave of Cellular Contractility for Epithelial Invagination. Dev Cell 2018; 46:162-172.e5. [PMID: 29983336 DOI: 10.1016/j.devcel.2018.06.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/27/2018] [Accepted: 06/06/2018] [Indexed: 01/24/2023]
Abstract
The dynamics of extracellular signal-regulated kinase (ERK) signaling underlies its versatile functions in cell differentiation, cell proliferation, and cell motility. Classical studies in Drosophila established that a gradient of epidermal growth factor receptor (EGFR)-ERK signaling is essential for these cellular responses. However, we challenge this view by the real-time monitoring of ERK activation; we show that a switch-like ERK activation is essential for the invagination movement of the Drosophila tracheal placode. This switch-like ERK activation stems from the positive feedback regulation of the EGFR-ERK signaling and a resultant relay of EGFR-ERK signaling among tracheal cells. A key transcription factor Trachealess (Trh) permissively regulates the iteration of the relay, and the ERK activation becomes graded in trh mutant. A mathematical model based on these observations and a molecular link between ERK activation dynamics and myosin shows that the relay mechanism efficiently promotes epithelial invagination while the gradient mechanism does not.
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Affiliation(s)
- Yosuke Ogura
- Laboratory for Morphogenetic Signaling, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Fu-Lai Wen
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Mustafa M Sami
- Laboratory for Morphogenetic Signaling, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Tatsuo Shibata
- Laboratory for Physical Biology, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Shigeo Hayashi
- Laboratory for Morphogenetic Signaling, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
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9
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Fraire-Zamora JJ, Jaeger J, Solon J. Two consecutive microtubule-based epithelial seaming events mediate dorsal closure in the scuttle fly Megaselia abdita. eLife 2018. [PMID: 29537962 PMCID: PMC5851697 DOI: 10.7554/elife.33807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Evolution of morphogenesis is generally associated with changes in genetic regulation. Here, we report evidence indicating that dorsal closure, a conserved morphogenetic process in dipterans, evolved as the consequence of rearrangements in epithelial organization rather than signaling regulation. In Drosophila melanogaster, dorsal closure consists of a two-tissue system where the contraction of extraembryonic amnioserosa and a JNK/Dpp-dependent epidermal actomyosin cable result in microtubule-dependent seaming of the epidermis. We find that dorsal closure in Megaselia abdita, a three-tissue system comprising serosa, amnion and epidermis, differs in morphogenetic rearrangements despite conservation of JNK/Dpp signaling. In addition to an actomyosin cable, M. abdita dorsal closure is driven by the rupture and contraction of the serosa and the consecutive microtubule-dependent seaming of amnion and epidermis. Our study indicates that the evolutionary transition to a reduced system of dorsal closure involves simplification of the seaming process without changing the signaling pathways of closure progression.
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Affiliation(s)
- Juan Jose Fraire-Zamora
- Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Johannes Jaeger
- Universitat Pompeu Fabra, Barcelona, Spain.,System Biology Programme, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Konrad Lorenz Institute for Evolution and Cognition Research (KLI), Klosterneuburg, Austria
| | - Jérôme Solon
- Cell and Developmental Biology Programme, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
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10
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Ochoa-Espinosa A, Harmansa S, Caussinus E, Affolter M. Myosin II is not required for Drosophila tracheal branch elongation and cell intercalation. Development 2017; 144:2961-2968. [PMID: 28811312 DOI: 10.1242/dev.148940] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 07/05/2017] [Indexed: 01/04/2023]
Abstract
The Drosophila tracheal system consists of an interconnected network of monolayered epithelial tubes that ensures oxygen transport in the larval and adult body. During tracheal dorsal branch (DB) development, individual DBs elongate as a cluster of cells, led by tip cells at the front and trailing cells in the rear. Branch elongation is accompanied by extensive cell intercalation and cell lengthening of the trailing stalk cells. Although cell intercalation is governed by Myosin II (MyoII)-dependent forces during tissue elongation in the Drosophila embryo that lead to germ-band extension, it remained unclear whether MyoII plays a similar active role during tracheal branch elongation and intercalation. Here, we have used a nanobody-based approach to selectively knock down MyoII in tracheal cells. Our data show that, despite the depletion of MyoII function, tip cell migration and stalk cell intercalation (SCI) proceed at a normal rate. This confirms a model in which DB elongation and SCI in the trachea occur as a consequence of tip cell migration, which produces the necessary forces for the branching process.
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Affiliation(s)
| | - Stefan Harmansa
- Biozentrum, University of Basel, Klingelbergstr. 50/70, 4056 Basel, Switzerland
| | - Emmanuel Caussinus
- Institute of Molecular Life Sciences (IMLS), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Affolter
- Biozentrum, University of Basel, Klingelbergstr. 50/70, 4056 Basel, Switzerland
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11
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Goodwin K, Nelson CM. Generating tissue topology through remodeling of cell-cell adhesions. Exp Cell Res 2017; 358:45-51. [PMID: 28322823 DOI: 10.1016/j.yexcr.2017.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 12/27/2022]
Abstract
During tissue morphogenesis, cellular rearrangements give rise to a large variety of three-dimensional structures. Final tissue architecture varies greatly across organs, and many develop to include combinations of folds, tubes, and branched networks. To achieve these different tissue geometries, constituent cells must follow different programs that dictate changes in shape and/or migratory behavior. One essential component of these changes is the remodeling of cell-cell adhesions. Invasive migratory behavior and separation between tissues require localized breakdown of cadherin-mediated adhesions. Conversely, tissue folding and fusion require the formation and reinforcement of cell-cell adhesions. Cell-cell adhesion plays a critical role in tissue morphogenesis; its manipulation may therefore prove to be invaluable in generating complex topologies ex vivo. Recapitulating these shapes in engineered tissues would enable a better understanding of how these processes occur in vivo, and may lead to improved design of organs for clinical applications. In this review, we discuss work investigating the formation of folds, tubes, and branched networks with an emphasis on known or possible roles for cell-cell adhesion. We then examine recently developed tools that could be adapted to manipulate cell-cell adhesion in engineered tissues.
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Affiliation(s)
- Katharine Goodwin
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, United States
| | - Celeste M Nelson
- Department of Chemical & Biological Engineering, Princeton University, Princeton, NJ 08544, United States; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States.
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12
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Caviglia S, Flores-Benitez D, Lattner J, Luschnig S, Brankatschk M. Rabs on the fly: Functions of Rab GTPases during development. Small GTPases 2017; 10:89-98. [PMID: 28118081 PMCID: PMC6380344 DOI: 10.1080/21541248.2017.1279725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The organization of intracellular transport processes is adapted specifically to different cell types, developmental stages, and physiologic requirements. Some protein traffic routes are universal to all cells and constitutively active, while other routes are cell-type specific, transient, and induced under particular conditions only. Small GTPases of the Rab (Ras related in brain) subfamily are conserved across eukaryotes and regulate most intracellular transit pathways. The complete sets of Rab proteins have been identified in model organisms, and molecular principles underlying Rab functions have been uncovered. Rabs provide intracellular landmarks that define intracellular transport sequences. Nevertheless, it remains a challenge to systematically map the subcellular distribution of all Rabs and their functional interrelations. This task requires novel tools to precisely describe and manipulate the Rab machinery in vivo. Here we discuss recent findings about Rab roles during development and we consider novel approaches to investigate Rab functions in vivo.
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Affiliation(s)
- Sara Caviglia
- a Danish Stem Cell Center (DanStem), University of Copenhagen , Copenhagen , Denmark.,c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland
| | - David Flores-Benitez
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Johanna Lattner
- b Max Planck Institute for Cell Biology and Genetics (MPI-CBG) , Dresden , Germany
| | - Stefan Luschnig
- c Institute of Molecular Life Sciences and Ph.D. Program in Molecular Life Sciences, University of Zurich , Zurich , Switzerland.,d Institute of Neurobiology and Cluster of Excellence Cells-in-Motion (EXC 1003 - CiM), University of Münster , Münster , Germany
| | - Marko Brankatschk
- e The Biotechnological Center of the TU Dresden (BIOTEC) , Dresden , Germany
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13
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Miao G, Hayashi S. Escargot controls the sequential specification of two tracheal tip cell types by suppressing FGF signaling in Drosophila. Development 2016; 143:4261-4271. [PMID: 27742749 PMCID: PMC5117212 DOI: 10.1242/dev.133322] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 10/04/2016] [Indexed: 01/05/2023]
Abstract
Extrinsic branching factors promote the elongation and migration of tubular organs. In the Drosophila tracheal system, Branchless (Drosophila FGF) stimulates the branching program by specifying tip cells that acquire motility and lead branch migration to a specific destination. Tip cells have two alternative cell fates: the terminal cell (TC), which produces long cytoplasmic extensions with intracellular lumen, and the fusion cell (FC), which mediates branch connections to form tubular networks. How Branchless controls this specification of cells with distinct shapes and behaviors is unknown. Here we report that this cell type diversification involves the modulation of FGF signaling by the zinc-finger protein Escargot (Esg), which is expressed in the FC and is essential for its specification. The dorsal branch begins elongation with a pair of tip cells with high FGF signaling. When the branch tip reaches its final destination, one of the tip cells becomes an FC and expresses Esg. FCs and TCs differ in their response to FGF: TCs are attracted by FGF, whereas FCs are repelled. Esg suppresses ERK signaling in FCs to control this differential migratory behavior. Summary: The migratory behavior of tracheal fusion cells is controlled by the FGF-induced expression of the transcription factor Escargot, which subsequently suppresses ERK signaling.
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Affiliation(s)
- Guangxia Miao
- Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.,Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan
| | - Shigeo Hayashi
- Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan .,Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan
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