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Vázquez-Liébanas E, Mocci G, Li W, Laviña B, Reddy A, O'Connor C, Hudson N, Elbeck Z, Nikoloudis I, Gaengel K, Vanlandewijck M, Campbell M, Betsholtz C, Mäe MA. Mosaic deletion of claudin-5 reveals rapid non-cell-autonomous consequences of blood-brain barrier leakage. Cell Rep 2024; 43:113911. [PMID: 38446668 DOI: 10.1016/j.celrep.2024.113911] [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: 07/14/2023] [Revised: 12/19/2023] [Accepted: 02/16/2024] [Indexed: 03/08/2024] Open
Abstract
Claudin-5 (CLDN5) is an endothelial tight junction protein essential for blood-brain barrier (BBB) formation. Abnormal CLDN5 expression is common in brain disease, and knockdown of Cldn5 at the BBB has been proposed to facilitate drug delivery to the brain. To study the consequences of CLDN5 loss in the mature brain, we induced mosaic endothelial-specific Cldn5 gene ablation in adult mice (Cldn5iECKO). These mice displayed increased BBB permeability to tracers up to 10 kDa in size from 6 days post induction (dpi) and ensuing lethality from 10 dpi. Single-cell RNA sequencing at 11 dpi revealed profound transcriptomic differences in brain endothelial cells regardless of their Cldn5 status in mosaic mice, suggesting major non-cell-autonomous responses. Reactive microglia and astrocytes suggested rapid cellular responses to BBB leakage. Our study demonstrates a critical role for CLDN5 in the adult BBB and provides molecular insight into the consequences and risks associated with CLDN5 inhibition.
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Affiliation(s)
- Elisa Vázquez-Liébanas
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Giuseppe Mocci
- Single Cell Core Facility of Flemingsberg Campus (SICOF), Karolinska Institute, 14157 Huddinge, Sweden
| | - Weihan Li
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Bàrbara Laviña
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Avril Reddy
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Claire O'Connor
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Natalie Hudson
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Zaher Elbeck
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Ioannis Nikoloudis
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Konstantin Gaengel
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Michael Vanlandewijck
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden; Single Cell Core Facility of Flemingsberg Campus (SICOF), Karolinska Institute, 14157 Huddinge, Sweden; Department of Medicine, Karolinska Institute, 14157 Huddinge, Sweden
| | - Matthew Campbell
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Christer Betsholtz
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden; Department of Medicine, Karolinska Institute, 14157 Huddinge, Sweden
| | - Maarja Andaloussi Mäe
- Department of Immunology, Genetics, and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden.
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2
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Bernier-Latmani J, González-Loyola A, Petrova TV. Mechanisms and functions of intestinal vascular specialization. J Exp Med 2024; 221:e20222008. [PMID: 38051275 PMCID: PMC10697212 DOI: 10.1084/jem.20222008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023] Open
Abstract
The intestinal vasculature has been studied for the last 100 years, and its essential role in absorbing and distributing ingested nutrients is well known. Recently, fascinating new insights into the organization, molecular mechanisms, and functions of intestinal vessels have emerged. These include maintenance of intestinal epithelial cell function, coping with microbiota-induced inflammatory pressure, recruiting gut-specific immune cells, and crosstalk with other organs. Intestinal function is also regulated at the systemic and cellular levels, such that the postprandial hyperemic response can direct up to 30% of systemic blood to gut vessels, while micron-sized endothelial cell fenestrations are necessary for nutrient uptake. In this review, we will highlight past discoveries made about intestinal vasculature in the context of new findings of molecular mechanisms underpinning gut function. Such comprehensive understanding of the system will pave the way to breakthroughs in nutrient uptake optimization, drug delivery efficiency, and treatment of human diseases.
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Affiliation(s)
- Jeremiah Bernier-Latmani
- Department of Oncology, University of Lausanne and Ludwig Institute for Cancer Research Lausanne, Lausanne, Switzerland
| | | | - Tatiana V. Petrova
- Department of Oncology, University of Lausanne and Ludwig Institute for Cancer Research Lausanne, Lausanne, Switzerland
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
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3
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Shaping subcellular tubes through vesicle trafficking: Common and distinct pathways. Semin Cell Dev Biol 2023; 133:74-82. [PMID: 35365398 DOI: 10.1016/j.semcdb.2022.03.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/23/2022]
Abstract
Cells with subcellular lumens form some of the most miniature tubes in the tubular organs of animals. These are often crucial components of the system, executing functions at remote body locations. Unlike tubes formed by intercellular or autocellular junctions, the cells with junctionless subcellular lumens face unique challenges in modifying the cell shape and plasma membrane organization to incorporate a membrane-bound tube within, often associated with dramatic cellular growth and extensions. Results in the recent years have shown that membrane dynamics, including both the primary delivery and recycling, is crucial in providing the cell with the flexibility to face these challenges. A significant portion of this information has come from two in vivo invertebrate models; the Drosophila tracheal terminal cells and the C. elegans excretory cell. This review focuses on the data obtained from these systems in the recent past about how trafficking pathways influence subcellular tube and branching morphogenesis. Given that such tubes occur in vertebrate vasculature, these insights are relevant to human health, and we contrast our conclusions with the less understood subcellular tubes of angiogenesis.
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4
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Paramore SV, Goodwin K, Nelson CM. How to build an epithelial tree. Phys Biol 2022; 19. [DOI: 10.1088/1478-3975/ac9e38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 10/27/2022] [Indexed: 11/23/2022]
Abstract
Abstract
Nature has evolved a variety of mechanisms to build epithelial trees of diverse architectures within different organs and across species. Epithelial trees are elaborated through branch initiation and extension, and their morphogenesis ends with branch termination. Each of these steps of the branching process can be driven by the actions of epithelial cells themselves (epithelial-intrinsic mechanisms) or by the cells of their surrounding tissues (epithelial-extrinsic mechanisms). Here, we describe examples of how these mechanisms drive each stage of branching morphogenesis, drawing primarily from studies of the lung, kidney, salivary gland, mammary gland, and pancreas, all of which contain epithelial trees that form through collective cell behaviors. Much of our understanding of epithelial branching comes from experiments using mice, but we also include examples here from avian and reptilian models. Throughout, we highlight how distinct mechanisms are employed in different organs and species to build epithelial trees. We also highlight how similar morphogenetic motifs are used to carry out conserved developmental programs or repurposed to support novel ones. Understanding the unique strategies used by nature to build branched epithelia from across the tree of life can help to inspire creative solutions to problems in tissue engineering and regenerative medicine.
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5
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Lepeta K, Roubinet C, Bauer M, Vigano MA, Aguilar G, Kanca O, Ochoa-Espinosa A, Bieli D, Cabernard C, Caussinus E, Affolter M. Engineered kinases as a tool for phosphorylation of selected targets in vivo. J Cell Biol 2022; 221:213463. [PMID: 36102907 PMCID: PMC9477969 DOI: 10.1083/jcb.202106179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 05/19/2022] [Accepted: 07/27/2022] [Indexed: 11/22/2022] Open
Abstract
Reversible protein phosphorylation by kinases controls a plethora of processes essential for the proper development and homeostasis of multicellular organisms. One main obstacle in studying the role of a defined kinase–substrate interaction is that kinases form complex signaling networks and most often phosphorylate multiple substrates involved in various cellular processes. In recent years, several new approaches have been developed to control the activity of a given kinase. However, most of them fail to regulate a single protein target, likely hiding the effect of a unique kinase–substrate interaction by pleiotropic effects. To overcome this limitation, we have created protein binder-based engineered kinases that permit a direct, robust, and tissue-specific phosphorylation of fluorescent fusion proteins in vivo. We show the detailed characterization of two engineered kinases based on Rho-associated protein kinase (ROCK) and Src. Expression of synthetic kinases in the developing fly embryo resulted in phosphorylation of their respective GFP-fusion targets, providing for the first time a means to direct the phosphorylation to a chosen and tagged target in vivo. We presume that after careful optimization, the novel approach we describe here can be adapted to other kinases and targets in various eukaryotic genetic systems to regulate specific downstream effectors.
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Affiliation(s)
| | - Chantal Roubinet
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK 2
| | - Milena Bauer
- Biozentrum, University of Basel, Basel, Switzerland 1
| | | | | | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 3
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6
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Sirocko KT, Angstmann H, Papenmeier S, Wagner C, Spohn M, Indenbirken D, Ehrhardt B, Kovacevic D, Hammer B, Svanes C, Rabe KF, Roeder T, Uliczka K, Krauss-Etschmann S. Early-life exposure to tobacco smoke alters airway signaling pathways and later mortality in D. melanogaster. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 309:119696. [PMID: 35780997 DOI: 10.1016/j.envpol.2022.119696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 05/31/2022] [Accepted: 06/26/2022] [Indexed: 06/15/2023]
Abstract
Early life environmental influences such as exposure to cigarette smoke (CS) can disturb molecular processes of lung development and thereby increase the risk for later development of chronic respiratory diseases. Among the latter, asthma and chronic obstructive pulmonary disease (COPD) are the most common. The airway epithelium plays a key role in their disease pathophysiology but how CS exposure in early life influences airway developmental pathways and epithelial stress responses or survival is poorly understood. Using Drosophila melanogaster larvae as a model for early life, we demonstrate that CS enters the entire larval airway system, where it activates cyp18a1 which is homologues to human CYP1A1 to metabolize CS-derived polycyclic aromatic hydrocarbons and further induces heat shock protein 70. RNASeq studies of isolated airways showed that CS dysregulates pathways involved in oxidative stress response, innate immune response, xenobiotic and glutathione metabolic processes as well as developmental processes (BMP, FGF signaling) in both sexes, while other pathways were exclusive to females or males. Glutathione S-transferase genes were further validated by qPCR showing upregulation of gstD4, gstD5 and gstD8 in respiratory tracts of females, while gstD8 was downregulated and gstD5 unchanged in males. ROS levels were increased in airways after CS. Exposure to CS further resulted in higher larval mortality, lower larval-pupal transition, and hatching rates in males only as compared to air-exposed controls. Taken together, early life CS induces airway epithelial stress responses and dysregulates pathways involved in the fly's branching morphogenesis as well as in mammalian lung development. CS further affected fitness and development in a highly sex-specific manner.
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Affiliation(s)
- Karolina-Theresa Sirocko
- Division for Invertebrate Models, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | | | - Stephanie Papenmeier
- Division for Invertebrate Models, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - Christina Wagner
- Division for Invertebrate Models, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany; Division of Innate Immunity, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - Michael Spohn
- Technology Platform Next Generation Sequencing, Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Daniela Indenbirken
- Technology Platform Next Generation Sequencing, Leibniz Institute of Virology (LIV), Hamburg, Germany
| | | | - Draginja Kovacevic
- DZL Laboratory - Experimental Microbiome Research, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany; Division of Early Origins of Chronic Lung Disease
| | - Barbara Hammer
- DZL Laboratory - Experimental Microbiome Research, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany; Division of Early Origins of Chronic Lung Disease
| | - Cecilie Svanes
- Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway; Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway
| | - Klaus F Rabe
- LungenClinic, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany; Department of Medicine, Christian Albrechts University, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Kiel, Germany
| | - Thomas Roeder
- Division of Molecular Physiology, Institute of Zoology, Christian-Albrechts University Kiel, Kiel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Germany
| | - Karin Uliczka
- Division of Innate Immunity, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany; Division of Early Origins of Chronic Lung Disease
| | - Susanne Krauss-Etschmann
- Institute of Experimental Medicine, Christian-Albrechts-Universität zu Kiel, Kiel, Germany; Division of Early Origins of Chronic Lung Disease.
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7
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Lam G, Beebe K, Thummel CS. A direct-drive GFP reporter for studies of tracheal development in Drosophila. Fly (Austin) 2022; 16:105-110. [PMID: 35094652 PMCID: PMC8803062 DOI: 10.1080/19336934.2022.2030191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Geanette Lam
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Katherine Beebe
- Molecular Medicine Program, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Carl S. Thummel
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA
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8
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Bilder D, Ong K, Hsi TC, Adiga K, Kim J. Tumour-host interactions through the lens of Drosophila. Nat Rev Cancer 2021; 21:687-700. [PMID: 34389815 PMCID: PMC8669834 DOI: 10.1038/s41568-021-00387-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/01/2021] [Indexed: 02/07/2023]
Abstract
There is a large gap between the deep understanding of mechanisms driving tumour growth and the reasons why patients ultimately die of cancer. It is now appreciated that interactions between the tumour and surrounding non-tumour (sometimes referred to as host) cells play critical roles in mortality as well as tumour progression, but much remains unknown about the underlying molecular mechanisms, especially those that act beyond the tumour microenvironment. Drosophila has a track record of high-impact discoveries about cell-autonomous growth regulation, and is well suited to now probe mysteries of tumour - host interactions. Here, we review current knowledge about how fly tumours interact with microenvironmental stroma, circulating innate immune cells and distant organs to influence disease progression. We also discuss reciprocal regulation between tumours and host physiology, with a particular focus on paraneoplasias. The fly's simplicity along with the ability to study lethality directly provide an opportunity to shed new light on how cancer actually kills.
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Affiliation(s)
- David Bilder
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
| | - Katy Ong
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Tsai-Ching Hsi
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Kavya Adiga
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Jung Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
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9
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Yin J, Heutschi D, Belting HG, Affolter M. Building the complex architectures of vascular networks: Where to branch, where to connect and where to remodel? Curr Top Dev Biol 2021; 143:281-297. [PMID: 33820624 DOI: 10.1016/bs.ctdb.2021.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cardiovascular system is the first organ to become functional during vertebrate embryogenesis and is responsible for the distribution of oxygen and nutrients to all cells of the body. The cardiovascular system constitutes a circulatory loop in which blood flows from the heart through arteries into the microvasculature and back through veins to the heart. The vasculature is characterized by the heterogeneity of blood vessels with respect to size, cellular architecture and function, including both larger vessels that are found at defined positions within the body and smaller vessels or vascular beds that are organized in a less stereotyped manner. Recent studies have shed light on how the vascular tree is formed and how the interconnection of all branches is elaborated and maintained. In contrast to many other branched organs such as the lung or the kidney, vessel connection (also called anastomosis) is a key process underlying the formation of vascular networks; each outgrowing angiogenic sprout must anastomose in order to allow blood flow in the newly formed vessel segment. It turns out that during this "sprouting and anastomosis" process, too many vessels are generated, and that blood flow is subsequently optimized through the removal (pruning) of low flow segments. Here, we reflect on the cellular and molecular mechanisms involved in forming the complex architecture of the vasculature through sprouting, anastomosis and pruning, and raise some questions that remain to be addressed in future studies.
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Affiliation(s)
- Jianmin Yin
- Biozentrum der Universität Basel, Basel, Switzerland
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10
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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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11
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Buechner M, Yang Z, Al-Hashimi H. A Series of Tubes: The C. elegans Excretory Canal Cell as a Model for Tubule Development. J Dev Biol 2020; 8:jdb8030017. [PMID: 32906663 PMCID: PMC7557474 DOI: 10.3390/jdb8030017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 08/31/2020] [Accepted: 09/02/2020] [Indexed: 12/25/2022] Open
Abstract
Formation and regulation of properly sized epithelial tubes is essential for multicellular life. The excretory canal cell of C. elegans provides a powerful model for investigating the integration of the cytoskeleton, intracellular transport, and organismal physiology to regulate the developmental processes of tube extension, lumen formation, and lumen diameter regulation in a narrow single cell. Multiple studies have provided new understanding of actin and intermediate filament cytoskeletal elements, vesicle transport, and the role of vacuolar ATPase in determining tube size. Most of the genes discovered have clear homologues in humans, with implications for understanding these processes in mammalian tissues such as Schwann cells, renal tubules, and brain vasculature. The results of several new genetic screens are described that provide a host of new targets for future studies in this informative structure.
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Affiliation(s)
- Matthew Buechner
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA;
- Correspondence:
| | - Zhe Yang
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA;
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12
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Short KM, Smyth IM. Branching morphogenesis as a driver of renal development. Anat Rec (Hoboken) 2020; 303:2578-2587. [PMID: 32790143 DOI: 10.1002/ar.24486] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 12/16/2022]
Abstract
Branching morphogenesis is an integral developmental mechanism central to the formation of a range of organs including the kidney, lung, pancreas and mammary gland. The ramified networks of epithelial tubules it establishes are critical for the processes of secretion, excretion and exchange mediated by these tissues. In the kidney, branching serves to establish the collecting duct system that transports urine from the nephrons into the renal pelvis, ureter and finally the bladder. Generally speaking, the formation of these networks in different organs begins with the specification and differentiation of simple bud-like organ anlage, which then undergo a process of elaboration, typically by bifurcation. This process is often governed by the interaction of progenitor cells at the tips of the epithelia with neighboring mesenchymal cell populations which direct the branching process and which often themselves differentiate to form part of the adult organ. In the kidney, the tips of ureteric bud elaborate through a dynamic cell signaling relationship with overlying nephron progenitor cell populations. These cells sequentially commit to differentiation and the resulting nephrons reintegrate with the ureteric epithelium as development progresses. This review will describe recent advances in understanding the how the elaboration of the ureteric bud is patterned and consider the extent to which this process is shared with other organs.
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Affiliation(s)
- Kieran M Short
- Department of Anatomy and Developmental Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
| | - Ian M Smyth
- Department of Anatomy and Developmental Biology, Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
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13
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Behr M, Riedel D. Glycosylhydrolase genes control respiratory tubes sizes and airway stability. Sci Rep 2020; 10:13377. [PMID: 32770153 PMCID: PMC7414880 DOI: 10.1038/s41598-020-70185-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/24/2020] [Indexed: 11/09/2022] Open
Abstract
Tight barriers are crucial for animals. Insect respiratory cells establish barriers through their extracellular matrices. These chitinous-matrices must be soft and flexible to provide ventilation, but also tight enough to allow oxygen flow and protection against dehydration, infections, and environmental stresses. However, genes that control soft, flexible chitin-matrices are poorly known. We investigated the genes of the chitinolytic glycosylhydrolase-family 18 in the tracheal system of Drosophila melanogaster. Our findings show that five chitinases and three chitinase-like genes organize the tracheal chitin-cuticles. Most of the chitinases degrade chitin from airway lumina to enable oxygen delivery. They further improve chitin-cuticles to enhance tube stability and integrity against stresses. Unexpectedly, some chitinases also support chitin assembly to expand the tube lumen properly. Moreover, Chitinase2 plays a decisive role in the chitin-cuticle formation that establishes taenidial folds to support tube stability. Chitinase2 is apically enriched on the surface of tracheal cells, where it controls the chitin-matrix architecture independently of other known cuticular proteins or chitinases. We suppose that the principle mechanisms of chitin-cuticle assembly and degradation require a set of critical glycosylhydrolases for flexible and not-flexible cuticles. The same glycosylhydrolases support thick laminar cuticle formation and are evolutionarily conserved among arthropods.
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Affiliation(s)
- Matthias Behr
- Institute for Biology, Leipzig University, Philipp-Rosenthal-Str. 55, 04103, Leipzig, Germany.
| | - Dietmar Riedel
- Max-Planck-Institute for Biophysical Chemistry, Electron Microscopy Group, 37077, Göttingen, Germany
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14
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Multiple Requirements for Rab GTPases in the Development of Drosophila Tracheal Dorsal Branches and Terminal Cells. G3-GENES GENOMES GENETICS 2020; 10:1099-1112. [PMID: 31980432 PMCID: PMC7056964 DOI: 10.1534/g3.119.400967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The tracheal epithelium in fruit fly larvae is a popular model for multi- and unicellular migration and morphogenesis. Like all epithelial cells, tracheal cells use Rab GTPases to organize their internal membrane transport, resulting in the specific localization or secretion of proteins on the apical or basal membrane compartments. Some contributions of Rabs to junctional remodelling and governance of tracheal lumen contents are known, but it is reasonable to assume that they play important further roles in morphogenesis. This pertains in particular to terminal tracheal cells, specialized branch-forming cells that drastically reshape both their apical and basal membrane during the larval stages. We performed a loss-of-function screen in the tracheal system, knocking down endogenously tagged alleles of 26 Rabs by targeting the tag via RNAi. This revealed that at least 14 Rabs are required to ensure proper cell fate specification and migration of the dorsal branches, as well as their epithelial fusion with the contralateral dorsal branch. The screen implicated four Rabs in the subcellular morphogenesis of terminal cells themselves. Further tests suggested residual gene function after knockdown, leading us to discuss the limitations of this approach. We conclude that more Rabs than identified here may be important for tracheal morphogenesis, and that the tracheal system offers great opportunities for studying several Rabs that have barely been characterized so far.
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15
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Araújo SJ. Centrosomes in Branching Morphogenesis. Results Probl Cell Differ 2019; 67:323-336. [PMID: 31435801 DOI: 10.1007/978-3-030-23173-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The centrosome, a major microtubule organizer, has important functions in regulating the cytoskeleton as well as the position of cellular structures and orientation of cells within tissues. The centrosome serves as the main cytoskeleton-organizing centre in the cell and is the classical site of microtubule nucleation and anchoring. For these reasons, centrosomes play a very important role in morphogenesis, not just in the early stages of cell divisions but also in the later stages of organogenesis. Many organs such as lung, kidney and blood vessels develop from epithelial tubes that branch into complex networks. Cells in the nervous system also form highly branched structures in order to build complex neuronal networks. During branching morphogenesis, cells have to rearrange within tissues though multicellular branching or through subcellular branching, also known as single-cell branching. For highly branched structures to be formed during embryonic development, the cytoskeleton needs to be extensively remodelled. The centrosome has been shown to play an important role during these events.
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Affiliation(s)
- Sofia J Araújo
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain.
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