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Facchini G, Rathery A, Douady S, Sillam-Dussès D, Perna A. Substrate evaporation drives collective construction in termites. eLife 2024; 12:RP86843. [PMID: 38597934 PMCID: PMC11006414 DOI: 10.7554/elife.86843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Abstract
Termites build complex nests which are an impressive example of self-organization. We know that the coordinated actions involved in the construction of these nests by multiple individuals are primarily mediated by signals and cues embedded in the structure of the nest itself. However, to date there is still no scientific consensus about the nature of the stimuli that guide termite construction, and how they are sensed by termites. In order to address these questions, we studied the early building behavior of Coptotermes gestroi termites in artificial arenas, decorated with topographic cues to stimulate construction. Pellet collections were evenly distributed across the experimental setup, compatible with a collection mechanism that is not affected by local topography, but only by the distribution of termite occupancy (termites pick pellets at the positions where they are). Conversely, pellet depositions were concentrated at locations of high surface curvature and at the boundaries between different types of substrate. The single feature shared by all pellet deposition regions was that they correspond to local maxima in the evaporation flux. We can show analytically and we confirm experimentally that evaporation flux is directly proportional to the local curvature of nest surfaces. Taken together, our results indicate that surface curvature is sufficient to organize termite building activity and that termites likely sense curvature indirectly through substrate evaporation. Our findings reconcile the apparently discordant results of previous studies.
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Affiliation(s)
- Giulio Facchini
- Life Sciences Department, University of RoehamptonLondonUnited Kingdom
- Service de Chimie et Physique Non Linéaire, Université Libre de BruxellesBrusselsBelgium
- Laboratoire Matière et Systèmes Complexe, CNRS, Université Paris CitéParisFrance
| | - Alann Rathery
- Life Sciences Department, University of RoehamptonLondonUnited Kingdom
| | - Stéphane Douady
- Laboratoire Matière et Systèmes Complexe, CNRS, Université Paris CitéParisFrance
| | - David Sillam-Dussès
- Laboratoire d’Ethologie Expérimentale et Comparée, LEEC, UR 4443, Université Sorbonne Paris NordVilletaneuseFrance
| | - Andrea Perna
- Life Sciences Department, University of RoehamptonLondonUnited Kingdom
- Networks Unit, IMT School for Advanced Studies LuccaLuccaItaly
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2
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Krajnc M, Fei C, Košmrlj A, Kalin M, Stopar D. Mechanical constraints to unbound expansion of B. subtilis on semi-solid surfaces. Microbiol Spectr 2024; 12:e0274023. [PMID: 38047692 PMCID: PMC10783106 DOI: 10.1128/spectrum.02740-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/13/2023] [Indexed: 12/05/2023] Open
Abstract
IMPORTANCE How bacterial cells colonize new territory is a problem of fundamental microbiological and biophysical interest and is key to the emergence of several phenomena of biological, ecological, and medical relevance. Here, we demonstrate how bacteria stuck in a colony of finite size can resume exploration of new territory by aquaplaning and how they fine tune biofilm viscoelasticity to surface material properties that allows them differential mobility. We show how changing local interfacial forces and colony viscosity results in a plethora of bacterial morphologies on surfaces with different physical and mechanical properties.
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Affiliation(s)
- Mojca Krajnc
- Biotechnical Faculty, Department of Microbiology, University of Ljubljana, Ljubljana, Slovenia
| | - Chenyi Fei
- Lewis-Sigler Institute for Integrative Genomics, Carl C. Icahn Laboratory, Princeton University, Princeton, New Jersey, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, USA
- Princeton Materials Institute, Princeton University, Princeton, New Jersey, USA
| | - Mitjan Kalin
- Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - David Stopar
- Biotechnical Faculty, Department of Microbiology, University of Ljubljana, Ljubljana, Slovenia
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3
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Morikawa K, Morita S, Sakura K, Maeno A, Gotoh H, Niimi T, Inoue Y. Unveiling the role of differential growth in 3D morphogenesis: An inference method to analyze area expansion rate distribution in biological systems. J Theor Biol 2023; 575:111650. [PMID: 37884223 DOI: 10.1016/j.jtbi.2023.111650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 10/28/2023]
Abstract
The three-dimensional (3D) morphologies of many organs in organisms, such as the curved shapes of leaves and flowers, the branching structure of lungs, and the exoskeletal shape of insects, are formed through surface growth. Although differential growth, a mode of surface growth, has been qualitatively identified as 3D morphogenesis, a quantitative understanding of the mechanical contribution of differential growth is lacking. To address this, we developed a quantitative inference method to analyze the distribution of the area expansion rate, which governs the growth of surfaces into 3D morphology. To validate the accuracy of our method, we tested it on a basic 3D morphology that allowed for the theoretical derivation of the area expansion rate distribution, and then assessed the difference between the predicted outcome and the theoretical solution. We also applied this method to complex 3D shapes and evaluated its accuracy through numerical experiments. The findings of the study revealed a linear decrease in error on a log-log scale with an increase in the number of meshes in both evaluations. This affirmed the reliability of the predictions for meshes that are sufficiently refined. Moreover, we employed our methodology to analyze the developmental process of the Japanese rhinoceros beetle Trypoxylus dichotomus, which is characterized by differential growth regulating 3D morphogenesis. The results indicated a notably high rate of area expansion on the left and right edges of the horn primordium, which is consistent with the experimental evidence of a higher rate of cell division in these regions. Hence, these findings confirm the efficacy of the proposed method in analyzing biological systems.
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Affiliation(s)
- Kentaro Morikawa
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Japan.
| | - Shinichi Morita
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Japan; Basic Biology Program, Graduate Institute for Advanced Studies, The Graduate University for Advanced Studies, SOKENDAI, Japan
| | - Kazuki Sakura
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Japan
| | | | - Hiroki Gotoh
- Department of Biological Science, Faculty of Science, Shizuoka University, Japan
| | - Teruyuki Niimi
- Division of Evolutionary Developmental Biology, National Institute for Basic Biology, Japan; Basic Biology Program, Graduate Institute for Advanced Studies, The Graduate University for Advanced Studies, SOKENDAI, Japan
| | - Yasuhiro Inoue
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, Japan.
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4
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Humbert MV, Spalluto CM, Bell J, Blume C, Conforti F, Davies ER, Dean LSN, Elkington P, Haitchi HM, Jackson C, Jones MG, Loxham M, Lucas JS, Morgan H, Polak M, Staples KJ, Swindle EJ, Tezera L, Watson A, Wilkinson TMA. Towards an artificial human lung: modelling organ-like complexity to aid mechanistic understanding. Eur Respir J 2022; 60:2200455. [PMID: 35777774 DOI: 10.1183/13993003.00455-2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/11/2022] [Indexed: 11/05/2022]
Abstract
Respiratory diseases account for over 5 million deaths yearly and are a huge burden to healthcare systems worldwide. Murine models have been of paramount importance to decode human lung biology in vivo, but their genetic, anatomical, physiological and immunological differences with humans significantly hamper successful translation of research into clinical practice. Thus, to clearly understand human lung physiology, development, homeostasis and mechanistic dysregulation that may lead to disease, it is essential to develop models that accurately recreate the extraordinary complexity of the human pulmonary architecture and biology. Recent advances in micro-engineering technology and tissue engineering have allowed the development of more sophisticated models intending to bridge the gap between the native lung and its replicates in vitro Alongside advanced culture techniques, remarkable technological growth in downstream analyses has significantly increased the predictive power of human biology-based in vitro models by allowing capture and quantification of complex signals. Refined integrated multi-omics readouts could lead to an acceleration of the translational pipeline from in vitro experimental settings to drug development and clinical testing in the future. This review highlights the range and complexity of state-of-the-art lung models for different areas of the respiratory system, from nasal to large airways, small airways and alveoli, with consideration of various aspects of disease states and their potential applications, including pre-clinical drug testing. We explore how development of optimised physiologically relevant in vitro human lung models could accelerate the identification of novel therapeutics with increased potential to translate successfully from the bench to the patient's bedside.
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Affiliation(s)
- Maria Victoria Humbert
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Cosma Mirella Spalluto
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- M.V. Humbert and C.M. Spalluto are co-first authors and contributed equally to this work
| | - Joseph Bell
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Cornelia Blume
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
- School of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Franco Conforti
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Elizabeth R Davies
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Lareb S N Dean
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Paul Elkington
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Hans Michael Haitchi
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Claire Jackson
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Mark G Jones
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Matthew Loxham
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Jane S Lucas
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Hywel Morgan
- Institute for Life Sciences, University of Southampton, Southampton, UK
- Electronics and Computer Science, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, UK
| | - Marta Polak
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Karl J Staples
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
| | - Emily J Swindle
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- Institute for Life Sciences, University of Southampton, Southampton, UK
| | - Liku Tezera
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Department of Infection and Immunity, Faculty of Medicine, University College London, London, UK
| | - Alastair Watson
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
- College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
- School of Clinical Medicine, University of Cambridge, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Tom M A Wilkinson
- School of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- NIHR Southampton Biomedical Research Centre, University Hospital Southampton, Southampton, UK
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5
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Nadir Kaplan C, Mahadevan L. Geometrical dynamics of edge-driven accretive surface growth. Proc Math Phys Eng Sci 2022. [DOI: 10.1098/rspa.2021.0638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Accretion of mineralized thin wall-like structures via localized growth along their edges is observed in physical and biological systems ranging from molluscan and brachiopod shells to carbonate–silica composite precipitates. To understand the shape of these mineralized structures, we develop a mathematical framework that treats the thin-walled shells as a smooth surface left in the wake of the growth front that can be described as an evolving space curve. Our theory then takes an explicit geometric form for the prescription of the velocity of the growth front curve, along with compatibility relations and a closure equation related to the nature of surface curling. Solutions of these equations capture a range of geometric precipitate patterns seen in abiotic and biotic forms across scales. In addition to providing a framework for the growth and form of these thin-walled morphologies, our theory suggests a new class of dynamical systems involving moving space curves that are compatible with non-Euclidean embeddings of surfaces.
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Affiliation(s)
- C. Nadir Kaplan
- Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Center for Soft Matter and Biological Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - L. Mahadevan
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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6
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Rippa AL, Alpeeva EV, Vasiliev AV, Vorotelyak EA. Alveologenesis: What Governs Secondary Septa Formation. Int J Mol Sci 2021; 22:ijms222212107. [PMID: 34829987 PMCID: PMC8618598 DOI: 10.3390/ijms222212107] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 12/30/2022] Open
Abstract
The simplification of alveoli leads to various lung pathologies such as bronchopulmonary dysplasia and emphysema. Deep insight into the process of emergence of the secondary septa during development and regeneration after pneumonectomy, and into the contribution of the drivers of alveologenesis and neo-alveolarization is required in an efficient search for therapeutic approaches. In this review, we describe the formation of the gas exchange units of the lung as a multifactorial process, which includes changes in the actomyosin cytoskeleton of alveocytes and myofibroblasts, elastogenesis, retinoic acid signaling, and the contribution of alveolar mesenchymal cells in secondary septation. Knowledge of the mechanistic context of alveologenesis remains incomplete. The characterization of the mechanisms that govern the emergence and depletion of αSMA will allow for an understanding of how the niche of fibroblasts is changing. Taking into account the intense studies that have been performed on the pool of lung mesenchymal cells, we present data on the typing of interstitial fibroblasts and their role in the formation and maintenance of alveoli. On the whole, when identifying cell subpopulations in lung mesenchyme, one has to consider the developmental context, the changing cellular functions, and the lability of gene signatures.
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7
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Cai W, Wang Y, Zhang J, Zhang H, Luo T. Multi-scale simulation of early kidney branching morphogenesis. Phys Biol 2021; 18:026005. [PMID: 33395673 DOI: 10.1088/1478-3975/abd844] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An important feature of the branch morphogenesis during kidney development is the termination of the tips on the outer surface of a kidney. This feature requires the avoidance of the intersection between the tips and existing ducts inside the kidney. Here, we started from a continuous model and implemented the coarse grained rules into a fast and discrete simulations. The ligand-receptor-based Turing mechanism suggests a repulsion that decreases exponentially with distance between interacting branches, preventing the intersection between neighboring branches. We considered this repulsive effect in numerical simulations and successfully reproduce the key features of the experimentally observed branch morphology for an E15.5 kidney. We examine the similarity of several geometrical parameters between the simulation results and experimental observations. The good agreement between the simulations and experiments suggests that the concentration decay caused by the absorption of glial cell line derived neurotrophic factor might be the key factor to affect the geometry in early kidney development.
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Affiliation(s)
- Wenran Cai
- 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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8
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Jones MR, Chong L, Bellusci S. Fgf10/Fgfr2b Signaling Orchestrates the Symphony of Molecular, Cellular, and Physical Processes Required for Harmonious Airway Branching Morphogenesis. Front Cell Dev Biol 2021; 8:620667. [PMID: 33511132 PMCID: PMC7835514 DOI: 10.3389/fcell.2020.620667] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/10/2020] [Indexed: 12/12/2022] Open
Abstract
Airway branching morphogenesis depends on the intricate orchestration of numerous biological and physical factors connected across different spatial scales. One of the key regulatory pathways controlling airway branching is fibroblast growth factor 10 (Fgf10) signaling via its epithelial fibroblast growth factor receptor 2b (Fgfr2b). Fine reviews have been published on the molecular mechanisms, in general, involved in branching morphogenesis, including those mechanisms, in particular, connected to Fgf10/Fgfr2b signaling. However, a comprehensive review looking at all the major biological and physical factors involved in branching, at the different scales at which branching operates, and the known role of Fgf10/Fgfr2b therein, is missing. In the current review, we attempt to summarize the existing literature on airway branching morphogenesis by taking a broad approach. We focus on the biophysical and mechanical forces directly shaping epithelial bud initiation, branch elongation, and branch tip bifurcation. We then shift focus to more passive means by which branching proceeds, via extracellular matrix remodeling and the influence of the other pulmonary arborized networks: the vasculature and nerves. We end the review by briefly discussing work in computational modeling of airway branching. Throughout, we emphasize the known or speculative effects of Fgfr2b signaling at each point of discussion. It is our aim to promote an understanding of branching morphogenesis that captures the multi-scalar biological and physical nature of the phenomenon, and the interdisciplinary approach to its study.
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Affiliation(s)
- Matthew R. Jones
- Key Laboratory of Interventional Pulmonology of Zhejiang Province, Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
- Cardio-Pulmonary Institute and Department of Pulmonary and Critical Care Medicine and Infectious Diseases, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig University Giessen, Giessen, Germany
| | - Lei Chong
- National Key Clinical Specialty of Pediatric Respiratory Medicine, Discipline of Pediatric Respiratory Medicine, Institute of Pediatrics, The Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Saverio Bellusci
- Key Laboratory of Interventional Pulmonology of Zhejiang Province, Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
- Cardio-Pulmonary Institute and Department of Pulmonary and Critical Care Medicine and Infectious Diseases, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig University Giessen, Giessen, Germany
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9
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Facchini G, Lazarescu A, Perna A, Douady S. A growth model driven by curvature reproduces geometric features of arboreal termite nests. J R Soc Interface 2020; 17:20200093. [PMID: 32693744 PMCID: PMC7423439 DOI: 10.1098/rsif.2020.0093] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We present a simple three-dimensional model to describe the autonomous expansion of a substrate whose growth is driven by the local mean curvature of its surface. The model aims to reproduce the nest construction process in arboreal Nasutitermes termites, whose cooperation may similarly be mediated by the shape of the structure they are walking on, for example focusing the building activity of termites where local mean curvature is high. We adopt a phase-field model where the nest is described by one continuous scalar field and its growth is governed by a single nonlinear equation with one adjustable parameter d. When d is large enough the equation is linearly unstable and fairly reproduces a growth process in which the initial walls expand, branch and merge, while progressively invading all the available space, which is consistent with the intricate structures of real nests. Interestingly, the linear problem associated with our growth equation is analogous to the buckling of a thin elastic plate under symmetric in-plane compression, which is also known to produce rich patterns through nonlinear and secondary instabilities. We validated our model by collecting nests of two species of arboreal Nasutitermes from the field and imaging their structure with a micro-computed tomography scanner. We found a strong resemblance between real and simulated nests, characterized by the emergence of a characteristic length scale and by the abundance of saddle-shaped surfaces with zero-mean curvature, which validates the choice of the driving mechanism of our growth model.
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Affiliation(s)
- G Facchini
- Life Sciences Department, University of Roehampton, London, UK
| | - A Lazarescu
- Institut de Recherche en Mathématique et Physique, UCLouvain, Louvain-la-Neuve, Belgium
| | - A Perna
- Life Sciences Department, University of Roehampton, London, UK
| | - S Douady
- Laboratoire Matière et Systèmes Complexes, Université Paris Diderot, Paris, France
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10
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Leonard-Duke J, Evans S, Hannan RT, Barker TH, Bates JHT, Bonham CA, Moore BB, Kirschner DE, Peirce SM. Multi-scale models of lung fibrosis. Matrix Biol 2020; 91-92:35-50. [PMID: 32438056 DOI: 10.1016/j.matbio.2020.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/13/2020] [Accepted: 04/15/2020] [Indexed: 02/08/2023]
Abstract
The architectural complexity of the lung is crucial to its ability to function as an organ of gas exchange; the branching tree structure of the airways transforms the tracheal cross-section of only a few square centimeters to a blood-gas barrier with a surface area of tens of square meters and a thickness on the order of a micron or less. Connective tissue comprised largely of collagen and elastic fibers provides structural integrity for this intricate and delicate system. Homeostatic maintenance of this connective tissue, via a balance between catabolic and anabolic enzyme-driven processes, is crucial to life. Accordingly, when homeostasis is disrupted by the excessive production of connective tissue, lung function deteriorates rapidly with grave consequences leading to chronic lung conditions such as pulmonary fibrosis. Understanding how pulmonary fibrosis develops and alters the link between lung structure and function is crucial for diagnosis, prognosis, and therapy. Further information gained could help elaborate how the healing process breaks down leading to chronic disease. Our understanding of fibrotic disease is greatly aided by the intersection of wet lab studies and mathematical and computational modeling. In the present review we will discuss how multi-scale modeling has facilitated our understanding of pulmonary fibrotic disease as well as identified opportunities that remain open and have produced techniques that can be incorporated into this field by borrowing approaches from multi-scale models of fibrosis beyond the lung.
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Affiliation(s)
- Julie Leonard-Duke
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephanie Evans
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Riley T Hannan
- Department of Pathology, University of Virginia, Charlottesville, VA 22908, USA
| | - Thomas H Barker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Jason H T Bates
- Department of Medicine, Vermont Lung Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Catherine A Bonham
- Division of Pulmonary and Critical Care Medicine, University of Virginia, Charlottesville VA 22908, USA
| | - Bethany B Moore
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, and Department of Microbiology and Immunology, University of Michigan Medical Center, Ann Arbor, MI, 48109, USA
| | - Denise E Kirschner
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Shayn M Peirce
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
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11
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Image-based modeling of kidney branching morphogenesis reveals GDNF-RET based Turing-type mechanism and pattern-modulating WNT11 feedback. Nat Commun 2019; 10:239. [PMID: 30651543 PMCID: PMC6484223 DOI: 10.1038/s41467-018-08212-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 12/22/2018] [Indexed: 11/08/2022] Open
Abstract
Branching patterns and regulatory networks differ between branched organs. It has remained unclear whether a common regulatory mechanism exists and how organ-specific patterns can emerge. Of all previously proposed signalling-based mechanisms, only a ligand-receptor-based Turing mechanism based on FGF10 and SHH quantitatively recapitulates the lung branching patterns. We now show that a GDNF-dependent ligand-receptor-based Turing mechanism quantitatively recapitulates branching of cultured wildtype and mutant ureteric buds, and achieves similar branching patterns when directing domain outgrowth in silico. We further predict and confirm experimentally that the kidney-specific positive feedback between WNT11 and GDNF permits the dense packing of ureteric tips. We conclude that the ligand-receptor based Turing mechanism presents a common regulatory mechanism for lungs and kidneys, despite the differences in the molecular implementation. Given its flexibility and robustness, we expect that the ligand-receptor-based Turing mechanism constitutes a likely general mechanism to guide branching morphogenesis and other symmetry breaks during organogenesis. Many organs develop through branching morphogenesis, but whether the underlying mechanisms are shared is unknown. Here, the authors show that a ligand-receptor based Turing mechanisms, similar to that observed in lung development, likely underlies branching morphogenesis of the kidney.
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12
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Lang C, Conrad L, Michos O. Mathematical Approaches of Branching Morphogenesis. Front Genet 2018; 9:673. [PMID: 30631344 PMCID: PMC6315180 DOI: 10.3389/fgene.2018.00673] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 12/04/2018] [Indexed: 12/16/2022] Open
Abstract
Many organs require a high surface to volume ratio to properly function. Lungs and kidneys, for example, achieve this by creating highly branched tubular structures during a developmental process called branching morphogenesis. The genes that control lung and kidney branching share a similar network structure that is based on ligand-receptor reciprocal signalling interactions between the epithelium and the surrounding mesenchyme. Nevertheless, the temporal and spatial development of the branched epithelial trees differs, resulting in organs of distinct shape and size. In the embryonic lung, branching morphogenesis highly depends on FGF10 signalling, whereas GDNF is the driving morphogen in the kidney. Knockout of Fgf10 and Gdnf leads to lung and kidney agenesis, respectively. However, FGF10 plays a significant role during kidney branching and both the FGF10 and GDNF pathway converge on the transcription factors ETV4/5. Although the involved signalling proteins have been defined, the underlying mechanism that controls lung and kidney branching morphogenesis is still elusive. A wide range of modelling approaches exists that differ not only in the mathematical framework (e.g., stochastic or deterministic) but also in the spatial scale (e.g., cell or tissue level). Due to advancing imaging techniques, image-based modelling approaches have proven to be a valuable method for investigating the control of branching events with respect to organ-specific properties. Here, we review several mathematical models on lung and kidney branching morphogenesis and suggest that a ligand-receptor-based Turing model represents a potential candidate for a general but also adaptive mechanism to control branching morphogenesis during development.
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Affiliation(s)
| | | | - Odyssé Michos
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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13
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Meyerholz DK, Stoltz DA, Gansemer ND, Ernst SE, Cook DP, Strub MD, LeClair EN, Barker CK, Adam RJ, Leidinger MR, Gibson-Corley KN, Karp PH, Welsh MJ, McCray PB. Lack of cystic fibrosis transmembrane conductance regulator disrupts fetal airway development in pigs. J Transl Med 2018; 98:825-838. [PMID: 29467455 PMCID: PMC6019641 DOI: 10.1038/s41374-018-0026-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/16/2017] [Accepted: 01/10/2018] [Indexed: 11/15/2022] Open
Abstract
Loss of cystic fibrosis transmembrane conductance regulator (CFTR) function causes cystic fibrosis (CF), predisposing the lungs to chronic infection and inflammation. In young infants with CF, structural airway defects are increasingly recognized before the onset of significant lung disease, which suggests a developmental origin and a possible role in lung disease pathogenesis. The role(s) of CFTR in lung development is unclear and developmental studies in humans with CF are not feasible. Young CF pigs have structural airway changes and develop spontaneous postnatal lung disease similar to humans; therefore, we studied lung development in the pig model (non-CF and CF). CF trachea and proximal airways had structural lesions detectable as early as pseudoglandular development. At this early developmental stage, budding CF airways had smaller, hypo-distended lumens compared to non-CF airways. Non-CF lung explants exhibited airway lumen distension in response to forskolin/IBMX as well as to fibroblast growth factor (FGF)-10, consistent with CFTR-dependent anion transport/secretion, but this was lacking in CF airways. We studied primary pig airway epithelial cell cultures and found that FGF10 increased cellular proliferation (non-CF and CF) and CFTR expression/function (in non-CF only). In pseudoglandular stage lung tissue, CFTR protein was exclusively localized to the leading edges of budding airways in non-CF (but not CF) lungs. This discreet microanatomic localization of CFTR is consistent with the site, during branching morphogenesis, where airway epithelia are responsive to FGF10 regulation. In summary, our results suggest that the CF proximal airway defects originate during branching morphogenesis and that the lack of CFTR-dependent anion transport/liquid secretion likely contributes to these hypo-distended airways.
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Affiliation(s)
- David K Meyerholz
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
| | - David A Stoltz
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Biomedical Engineering, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Nick D Gansemer
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Sarah E Ernst
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Daniel P Cook
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Matthew D Strub
- Department of Pediatrics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Erica N LeClair
- Department of Pediatrics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Carrie K Barker
- Department of Pediatrics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Ryan J Adam
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Biomedical Engineering, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Mariah R Leidinger
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Katherine N Gibson-Corley
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Philip H Karp
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael J Welsh
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Paul B McCray
- Department of Pediatrics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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14
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George UZ, Lubkin SR. Tissue geometry may govern lung branching mode selection. J Theor Biol 2018; 442:22-30. [PMID: 29330055 DOI: 10.1016/j.jtbi.2017.12.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 12/19/2017] [Accepted: 12/31/2017] [Indexed: 11/17/2022]
Abstract
Lung branching morphogenesis proceeds in three stereotyped modes (domain, planar, and orthogonal branching). Much is known about the molecular players, including growth factors such as fibroblast growth factor 10 but it is unknown how these signals could actuate the different branching patterns. With the aim of identifying mechanisms that may determine the different branching modes, we developed a computational model of the epithelial lung bud and its surrounding mesenchyme. We studied transport of morphogens and localization of morphogen flux at lobe surfaces and lobe edges. We find that a single simple mechanism is theoretically capable of directing an epithelial tubule to elongate, bend, flatten, or bifurcate, depending solely on geometric ratios of the tissues in the vicinity of a growing tubule tip. Furthermore, the same simple mechanism is capable of generating orthogonal or planar branching, depending only on the same geometric ratios.
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Affiliation(s)
- Uduak Z George
- College of Engineering, University of Georgia, Athens, GA 30602, USA.
| | - Sharon R Lubkin
- Department of Mathematics, North Carolina State University, Raleigh, NC 27695-8205, USA.
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15
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Dahl-Jensen SB, Figueiredo-Larsen M, Grapin-Botton A, Sneppen K. Short-range growth inhibitory signals from the epithelium can drive non-stereotypic branching in the pancreas. Phys Biol 2016; 13:016007. [PMID: 26906913 DOI: 10.1088/1478-3975/13/1/016007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Many organs such as the vasculature, kidney, lungs, pancreas and several other glands form ramified networks of tubes that either maximize exchange surfaces between two compartments or minimize the volume of an organ dedicated to the production and local delivery of a cell-derived product. The structure of these tubular networks can be stereotyped, as in the lungs, or stochastic with large variations between individuals, as in the pancreas. The principles driving stereotyped branching have attracted much attention and several models have been proposed and refined. Here we focus on the pancreas, as a model of non-stereotyped branching. In many ramified tubular organs, an important role of the mesenchyme as a source of branching signals has been proposed, including in the pancreas. However, our previous work has shown that in the absence of mesenchyme, epithelial cells seeded in vitro in Matrigel form heavily branched organoids. Here we experimentally show that pancreatic organoids grow primarily at the tips. Furthermore, in contrast to classical 'depletion of activator' mechanisms, organoids growing in close vicinity seem not to affect each other's growth before they get in contact. We recapitulate these observations in an in silico model of branching assuming a 'local inhibitor' is secreted by the epithelium. Remarkably this simple mechanism is sufficient to generate branched organoids similar to those observed in vitro, including their transition from filled spheres to a tree like structure. Quantifying the similarity between in silico and in vitro development through a normalized surface to volume ratio, our in silico model predicts that inhibition is likely to be cooperative and that the diffusing inhibitor decays within a length scale of 10-20 μm.
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Affiliation(s)
- Svend Bertel Dahl-Jensen
- DanStem, University of Copenhagen, 3B Blegdamsvej, DK-2200 Copenhagen N, Denmark. Center for Models of Life, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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16
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George UZ, Bokka KK, Warburton D, Lubkin SR. Quantifying stretch and secretion in the embryonic lung: Implications for morphogenesis. Mech Dev 2015; 138 Pt 3:356-63. [PMID: 26189687 DOI: 10.1016/j.mod.2015.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/09/2015] [Accepted: 07/10/2015] [Indexed: 12/21/2022]
Abstract
Branching in the embryonic lung is controlled by a variety of morphogens. Mechanics is also believed to play a significant role in lung branching. The relative roles and interactions of these two broad factors are challenging to determine. We considered three hypotheses for explaining why tracheal occlusion triples branching with no overall increase in size. Both hypotheses are based on tracheal occlusion blocking the exit of secretions. (H1) Increased lumen pressure stretches tissues; stretch receptors at shoulders of growing tips increase local rate of branching. (H2) Blocking exit of secretions blocks advective transport of morphogens, leading to (H2a) increased overall concentration of morphogens or (H2b) increased flux of morphogens at specific locations. We constructed and analyzed computational models of tissue stretch and solute transport in a 3D lung geometry. Observed tissue stresses and stretches were predominantly in locations unrelated to subsequent branch locations, suggesting that tissue stretch (H1) is not the mechanism of enhancement of branching. Morphogen concentration in the mesenchyme (H2a) increased with tracheal occlusion, consistent with previously reported results. Morphogen flux at the epithelial surface (H2b) completely changed its distribution pattern when the trachea was occluded, tripling the number of locations at which it was elevated. Our results are consistent with the hypothesis that tracheal occlusion blocks outflow of secretions, leading to a higher number of high-flux locations at branching tips, in turn leading to a large increase in number of branching locations.
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Affiliation(s)
- Uduak Z George
- North Carolina State University, Raleigh, NC 27695-8205, USA
| | - Kishore K Bokka
- North Carolina State University, Raleigh, NC 27695-8205, USA
| | - David Warburton
- Saban Research Institute, 4650 Sunset Boulevard, MS# 35, Los Angeles, CA 90027, USA
| | - Sharon R Lubkin
- North Carolina State University, Raleigh, NC 27695-8205, USA.
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17
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Legras A, Mordant P, Gibault L, Hernigou A, Le Pimpec Barthes F, Riquet M. [Diaphragmatic bronchogenic cyst: an exceptional location]. REVUE DE PNEUMOLOGIE CLINIQUE 2014; 70:357-361. [PMID: 25131363 DOI: 10.1016/j.pneumo.2014.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/04/2014] [Indexed: 06/03/2023]
Abstract
A 64-year-old man complained of persistent dyspnea and bilateral basi-thoracic pain with shoulder irradiation. Chest computed tomography revealed a heterogeneous left diaphragmatic mass, while magnetic resonance imaging showed hypo-T1 and hyper-T2 signal. Positron-emission tomography did not show any hypermetabolism. Video-assisted thoracic surgery was decided. At inspection, tumour appeared within the posterior costal part of the diaphragmatic muscle. Tumour resection was extended to a 8-cm-long portion of the lumbar part of diaphragm. Diaphragm was repaired with non-absorbable interrupted sutures. Postoperative course was uneventful. Final pathology revealed an intra-diaphragmatic bronchogenic cyst, which is an exceptional condition. Primary diaphragmatic tumours are very rare and preoperative diagnosis cannot be affirmed. Embryologic hypotheses (migration along the oesophagus or envelopment within diaphragmatic precursors of an abnormal supernumerary lung bud) including recent molecular findings of deregulated pathways (fibroblast growth factor-10 and NOTCH) are discussed.
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Affiliation(s)
- A Legras
- Département chirurgie thoracique et transplantation pulmonaire, université Paris-Descartes, hôpital européen Georges-Pompidou, 20, rue Leblanc, 75015 Paris, France
| | - P Mordant
- Département chirurgie thoracique et transplantation pulmonaire, université Paris-Descartes, hôpital européen Georges-Pompidou, 20, rue Leblanc, 75015 Paris, France
| | - L Gibault
- Service de cytologie et d'anatomie pathologique, université Paris-Descartes, hôpital européen Georges-Pompidou, 75015 Paris, France
| | - A Hernigou
- Service de radiologie, université Paris-Descartes, hôpital européen Georges-Pompidou, 75015 Paris, France
| | - F Le Pimpec Barthes
- Département chirurgie thoracique et transplantation pulmonaire, université Paris-Descartes, hôpital européen Georges-Pompidou, 20, rue Leblanc, 75015 Paris, France
| | - M Riquet
- Département chirurgie thoracique et transplantation pulmonaire, université Paris-Descartes, hôpital européen Georges-Pompidou, 20, rue Leblanc, 75015 Paris, France.
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18
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Menshykau D, Blanc P, Unal E, Sapin V, Iber D. An interplay of geometry and signaling enables robust lung branching morphogenesis. Development 2014; 141:4526-36. [PMID: 25359721 DOI: 10.1242/dev.116202] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Early branching events during lung development are stereotyped. Although key regulatory components have been defined, the branching mechanism remains elusive. We have now used a developmental series of 3D geometric datasets of mouse embryonic lungs as well as time-lapse movies of cultured lungs to obtain physiological geometries and displacement fields. We find that only a ligand-receptor-based Turing model in combination with a particular geometry effect that arises from the distinct expression domains of ligands and receptors successfully predicts the embryonic areas of outgrowth and supports robust branch outgrowth. The geometry effect alone does not support bifurcating outgrowth, while the Turing mechanism alone is not robust to noisy initial conditions. The negative feedback between the individual Turing modules formed by fibroblast growth factor 10 (FGF10) and sonic hedgehog (SHH) enlarges the parameter space for which the embryonic growth field is reproduced. We therefore propose that a signaling mechanism based on FGF10 and SHH directs outgrowth of the lung bud via a ligand-receptor-based Turing mechanism and a geometry effect.
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Affiliation(s)
- Denis Menshykau
- Department of Biosystems, Science and Engineering (D-BSSE), ETH Zurich, Mattenstraße 26, 4058 Basel, Switzerland Swiss Institute of Bioinformatics (SIB), Mattenstraße 26, 4058 Basel, Switzerland
| | - Pierre Blanc
- R2D2/Retinoids, Reproduction, Developmental Diseases, Faculté de Médecine, 28 Place Henri Dunant, BP 38, 63001 Clermont-Ferrand Cedex, France
| | - Erkan Unal
- Department of Biosystems, Science and Engineering (D-BSSE), ETH Zurich, Mattenstraße 26, 4058 Basel, Switzerland Swiss Institute of Bioinformatics (SIB), Mattenstraße 26, 4058 Basel, Switzerland Developmental Genetics, Department Biomedicine, University of Basel, Mattenstraße 28, 4058 Basel, Switzerland
| | - Vincent Sapin
- R2D2/Retinoids, Reproduction, Developmental Diseases, Faculté de Médecine, 28 Place Henri Dunant, BP 38, 63001 Clermont-Ferrand Cedex, France
| | - Dagmar Iber
- Department of Biosystems, Science and Engineering (D-BSSE), ETH Zurich, Mattenstraße 26, 4058 Basel, Switzerland Swiss Institute of Bioinformatics (SIB), Mattenstraße 26, 4058 Basel, Switzerland
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19
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El Agha E, Bellusci S. Walking along the Fibroblast Growth Factor 10 Route: A Key Pathway to Understand the Control and Regulation of Epithelial and Mesenchymal Cell-Lineage Formation during Lung Development and Repair after Injury. SCIENTIFICA 2014; 2014:538379. [PMID: 25298902 PMCID: PMC4178922 DOI: 10.1155/2014/538379] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 08/07/2014] [Indexed: 06/04/2023]
Abstract
Basic research on embryonic lung development offers unique opportunities to make important discoveries that will impact human health. Developmental biologists interested in the molecular control of branching morphogenesis have intensively studied the developing lung, with its complex and seemingly stereotyped ramified structure. However, it is also an organ that is linked to a vast array of clinical problems in humans such as bronchopulmonary dysplasia in premature babies and emphysema, chronic obstructive pulmonary disease, fibrosis, and cancer in adults. Epithelial stem/progenitor cells reside in niches where they interact with specific extracellular matrices as well as with mesenchymal cells; the latter are still poorly characterized. Interactions of epithelial stem/progenitor cells with their microenvironments are usually instructive, controlling quiescence versus activation, proliferation, differentiation, and migration. During the past 18 years, Fgf10 has emerged not only as a marker for the distal lung mesenchyme during early lung development, but also as a key player in branching morphogenesis and a critical component of the niche for epithelial stem cells. In this paper, we will present the current knowledge regarding the lineage tree in the lung, with special emphasis on cell-lineage decisions in the lung mesenchyme and the role of Fgf10 in this context.
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Affiliation(s)
- Elie El Agha
- Department of Internal Medicine II, Universities of Giessen and Marburg Lung Center (UGMLC), Klinikstraße 36, 35392 Giessen, Hessen, Germany
- Member of the German Center for Lung Research (DZL), 35392 Giessen, Hessen, Germany
| | - Saverio Bellusci
- Department of Internal Medicine II, Universities of Giessen and Marburg Lung Center (UGMLC), Klinikstraße 36, 35392 Giessen, Hessen, Germany
- Member of the German Center for Lung Research (DZL), 35392 Giessen, Hessen, Germany
- Developmental Biology and Regenerative Program of the Saban Research Institute at Childrens Hospital Los Angeles and University of Southern California, Los Angeles, CA 90027, USA
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20
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Guo Y, Sun M, Garfinkel A, Zhao X. Mechanisms of side branching and tip splitting in a model of branching morphogenesis. PLoS One 2014; 9:e102718. [PMID: 25050616 PMCID: PMC4106868 DOI: 10.1371/journal.pone.0102718] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/24/2014] [Indexed: 11/29/2022] Open
Abstract
Recent experimental work in lung morphogenesis has described an elegant pattern of branching phenomena. Two primary forms of branching have been identified: side branching and tip splitting. In our previous study of lung branching morphogenesis, we used a 4 variable partial differential equation (PDE), due to Meinhardt, as our mathematical model to describe the reaction and diffusion of morphogens creating those branched patterns. By altering key parameters in the model, we were able to reproduce all the branching styles and the switch between branching modes. Here, we attempt to explain the branching phenomena described above, as growing out of two fundamental instabilities, one in the longitudinal (growth) direction and the other in the transverse direction. We begin by decoupling the original branching process into two semi-independent sub-processes, 1) a classic activator/inhibitor system along the growing stalk, and 2) the spatial growth of the stalk. We then reduced the full branching model into an activator/inhibitor model that embeds growth of the stalk as a controllable parameter, to explore the mechanisms that determine different branching patterns. We found that, in this model, 1) side branching results from a pattern-formation instability of the activator/inhibitor subsystem in the longitudinal direction. This instability is far from equilibrium, requiring a large inhomogeneity in the initial conditions. It successively creates periodic activator peaks along the growing stalk, each of which later on migrates out and forms a side branch; 2) tip splitting is due to a Turing-style instability along the transversal direction, that creates the spatial splitting of the activator peak into 2 simultaneously-formed peaks at the growing tip, the occurrence of which requires the widening of the growing stalk. Tip splitting is abolished when transversal stalk widening is prevented; 3) when both instabilities are satisfied, tip bifurcation occurs together with side branching.
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Affiliation(s)
- Yina Guo
- Institute of Robotics and Automatic Information Systems, Nankai University, Tianjin, China
| | - Mingzhu Sun
- Institute of Robotics and Automatic Information Systems, Nankai University, Tianjin, China
- State Key Laboratory of Robotics, Shenyang, China
| | - Alan Garfinkel
- Department of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (XZ); (AG)
| | - Xin Zhao
- Institute of Robotics and Automatic Information Systems, Nankai University, Tianjin, China
- Tianjin Key Laboratory of Intelligent Robotics, Tianjin, China
- * E-mail: (XZ); (AG)
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Yang J, Chen J. Developmental programs of lung epithelial progenitors: a balanced progenitor model. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 3:331-47. [PMID: 25124755 DOI: 10.1002/wdev.141] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/17/2014] [Accepted: 05/04/2014] [Indexed: 01/17/2023]
Abstract
UNLABELLED The daunting task of lung epithelium development is to transform a cluster of foregut progenitors into a three-dimensional (3D) tubular network with distinct cell types distributed at their appropriate locations. A complete understanding of lung development needs to address not only how, but also where, different cell types form. We propose that the lung epithelium forms through regulated deployment of three developmental programs: branching morphogenesis to expand progenitors and build a tree-like tubular network, airway differentiation to specify cells for the proximal conducting airways, and alveolar differentiation to specify cells for the peripheral gas exchange region. Each developmental program has its unique morphological features and molecular control mechanisms; their spatiotemporal coordination can be accounted for in a balanced progenitor model where progenitors balance between alternative developmental programs in response to spatiotemporal cues. This model integrates progenitor morphogenesis and differentiation, and provides new insights to lung immaturity in preterm birth and lung evolution. Advanced gene targeting and 3D imaging tools are needed to achieve a comprehensive understanding of lung epithelial progenitors on molecular, cellular, and morphological levels. For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The authors have declared no conflicts of interest for this article.
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Affiliation(s)
- Jun Yang
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA
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22
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Abstract
Branched structures are ubiquitous in nature, both in living and non-living systems. While the functional benefits of branching organogenesis are straightforward, the developmental mechanisms leading to the repeated branching of epithelia in surrounding mesoderm remain unclear. Both molecular and physical aspects of growth control seem to play a critical role in shape emergence and maintenance. On the molecular side, the existence of a gradient of growth-promoting ligand between epithelial tips and distal mesenchyme seems to be common to branched organs. On the physical side, the branching process seems to require a mechanism of real-time adaptation to local geometry, as suggested by the self-avoiding nature of branching events. In this paper, we investigate the outcomes of a general three-dimensional growth model, in which epithelial growth is implemented as a function of ligand income, while the mesenchyme is considered as a proliferating viscous medium. Our results suggest that the existence of a gradient of growth-promoting ligand between distal and proximal mesenchyme implies a growth instability of the epithelial sheet, resulting in spontaneous self-avoiding branching morphogenesis. While the general nature of the model prevents one from fitting the development of specific organs, it suggests that few ingredients are actually required to achieve branching organogenesis.
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Affiliation(s)
- Raphaël Clément
- Laboratoire J-A Dieudonné - UMR CNRS 7531, Parc Valrose - University Nice Sophia Antipolis, F-06100 Nice, France
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23
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Guo Y, Chen TH, Zeng X, Warburton D, Boström KI, Ho CM, Zhao X, Garfinkel A. Branching patterns emerge in a mathematical model of the dynamics of lung development. J Physiol 2013; 592:313-24. [PMID: 24247979 DOI: 10.1113/jphysiol.2013.261099] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Recent experimental work has described an elegant pattern of branching in the development of the lung. Multiple forms of branching have been identified, including side branching and tip bifurcation. A particularly interesting feature is the phenomenon of 'orthogonal rotation of the branching plane'. The lung must fill 3D space with the essentially 2D phenomenon of branching. It accomplishes this by rotating the branching plane by 90° with each generation. The mechanisms underlying this rotation are not understood. In general, the programmes that underlie branching have been hypothetically attributed to genetic 'subroutines' under the control of a 'global master routine' to invoke particular subroutines at the proper time and location, but the mechanisms of these routines are not known. Here, we demonstrate that fundamental mechanisms, the reaction and diffusion of biochemical morphogens, can create these patterns. We used a partial differential equation model that postulates three morphogens, which we identify with specific molecules in lung development. We found that cascades of branching events, including side branching, tip splitting and orthogonal rotation of the branching plane, all emerge immediately from the model, without further assumptions. In addition, we found that one branching mode can be easily switched to another, by increasing or decreasing the values of key parameters. This shows how a 'global master routine' could work by the alteration of a single parameter. Being able to simulate cascades of branching events is necessary to understand the critical features of branching, such as orthogonal rotation of the branching plane between successive generations, and branching mode switch during lung development. Thus, our model provides a paradigm for how genes could possibly act to produce these spatial structures. Our low-dimensional model gives a qualitative understanding of how generic physiological mechanisms can produce branching phenomena, and how the system can switch from one branching pattern to another using low-dimensional 'control knobs'. The model provides a number of testable predictions, some of which have already been observed (though not explained) in experimental work.
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Affiliation(s)
- Yina Guo
- Department of Medicine, A2-237 Center for Health Sciences, Los Angeles, California, USA 90095-1679. . X. Zhao: Institute of Robotics and Automatic Information Systems, Nankai University, Tianjin 300071, China.
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24
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Abstract
Many organs of higher organisms are heavily branched structures and arise by an apparently similar process of branching morphogenesis. Yet the regulatory components and local interactions that have been identified differ greatly in these organs. It is an open question whether the regulatory processes work according to a common principle and how far physical and geometrical constraints determine the branching process. Here, we review the known regulatory factors and physical constraints in lung, kidney, pancreas, prostate, mammary gland and salivary gland branching morphogenesis, and describe the models that have been formulated to analyse their impacts.
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Affiliation(s)
- Dagmar Iber
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Basel, Switzerland
- Swiss Institute of Bioinformatics (SIB), Basel, Switzerland
| | - Denis Menshykau
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Basel, Switzerland
- Swiss Institute of Bioinformatics (SIB), Basel, Switzerland
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Hagood JS, Ambalavanan N. Systems biology of lung development and regeneration: current knowledge and recommendations for future research. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2013; 5:125-33. [PMID: 23293056 DOI: 10.1002/wsbm.1205] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The lung begins as a simple outpouching of the foregut and develops by stages into a highly complex organ, the proper function of which is essential to life for terrestrial mammals. Interruption of normal lung development can result in death or chronic disease. Conversely, repair after lung injury, as well as many acquired diseases, involves recapitulation, often aberrant, of developmental pathways. The principal paradigms in lung development are branching morphogenesis and alveolar septation, but others, such as vasculogenesis, are critical. These are partially understood at the level of cellular differentiation and molecular signaling, but a true systems biology analysis of lung development and lung repair/regeneration, including bioinformatics analysis and integration of data from unbiased and complementary '-omics' level studies, is still lacking. The past decade has seen increasing numbers of genomic, proteomic, metabolomics, and epigenomic studies of lung development and lung remodeling. In many cases, these studies have confirmed the importance of pathways uncovered painstakingly through single-molecule approaches, but they have also uncovered novel and unexpected pathways and new paradigms such as noncoding RNA. Future studies will need to combine data from multiple repositories and apply novel mathematical and computational models in order to establish a systems-level understanding of this remarkable organ.
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Affiliation(s)
- James S Hagood
- Division of Respiratory Medicine, Department of Pediatrics, University of California-San Diego and Rady Children's Hospital of San Diego, La Jolla, CA, USA.
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Abstract
Branching morphogenesis is a widely spread phenomenon in nature. In organogenesis, it results from the inhomogeneous growth of the epithelial sheet, leading to its repeated branching into surrounding mesoderm. Lung morphogenesis is an emblematic example of tree-like organogenesis common to most mammals. The core signalling network is well identified, notably the Fgf10/Shh couple, required to initiate and maintain branching. In a previous study, we showed that the restriction by SHH of Fgf10 expression domain to distal mesenchyme spontaneously induces differential epithelial proliferation leading to branching. A simple Laplacian model qualitatively reproduced FGF10 dynamics in the mesenchyme and the spontaneous self-avoiding branching morphogenesis. However, early lung geometry has several striking features that remain to be addressed. In this paper, we investigate, through simulations and data analysis, if the FGF10-diffusion scenario accounts for the following aspects of lung morphology: size dispersion, asymmetry of branching events, and distal epithelium-mesothelium equilibrium. We report that they emerge spontaneously in the model, and that most of the underlying mechanisms can be understood as dynamical interactions between gradients and shape. This suggests that specific regulation may not be required for the emergence of these striking geometrical features.
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Affiliation(s)
- Raphaël Clément
- Laboratoire J-A Dieudonné, UMR CNRS 7531, Parc Valrose, Université Nice Sophia Antipolis, F-06100 Nice, France.
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