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Abdali SS, Yokoyama T, Yamamoto Y, Narita K, Hirakawa M, Saino T. Immunohistochemical analysis and distribution of epithelial mast cells in the rat larynx and trachea. Histochem Cell Biol 2024; 162:287-297. [PMID: 39031197 DOI: 10.1007/s00418-024-02309-6] [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] [Accepted: 07/09/2024] [Indexed: 07/22/2024]
Abstract
Mast cells (MCs) in rat airways have been classified into two subtypes: epithelial MCs and connective tissue MCs (CTMCs). However, the immunohistochemical characteristics, cellular morphology, and distribution of epithelial MCs in the upper airways remain unclear. The present study investigated the morphological characteristics and distribution of epithelial MCs using 5-hydroxytryptamine (5-HT) and other immunohistochemical markers in sectioned or whole-mount preparations of the rat larynx and trachea. A double immunofluorescence analysis revealed the colocalization of 5-HT immunoreactivity with c-kit, a stem cell factor receptor commonly used as a MC marker, in both epithelial MCs and CTMCs. Dopa decarboxylase, an enzyme involved in 5-HT synthesis, was detected in both subtypes, suggesting their ability to synthesize and release 5-HT. Tryptase and histidine decarboxylase (a biosynthetic enzyme of histamine), which are well-known mediators of MCs, were exclusive to CTMCs. Epithelial MCs were pleomorphic with long cytoplasmic processes, whereas CTMCs were round and lacked cytoplasmic processes. The density of epithelial MCs was significantly higher in the glottis and cranial part of the trachea than in the epiglottis and other parts of the trachea. The present results showed that the morphology and immunohistochemical characteristics of epithelial MCs were different from those of CTMCs in the rat larynx and trachea, and variform epithelial MCs were predominantly located at the entrance of the upper airways. Epithelial MCs may release 5-HT to regulate innate immune responses by modulating epithelial cell functions at the entrance gate of the upper airways.
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Affiliation(s)
- Sayed Sharif Abdali
- Department of Anatomy (Cell Biology), Iwate Medical University, 1-1-1 Idaidori, Yahaba-cho, Shiwa-gun, Iwate, 028-3694, Japan.
| | - Takuya Yokoyama
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate, 020-8550, Japan
| | - Keishi Narita
- Department of Anatomy (Cell Biology), Iwate Medical University, 1-1-1 Idaidori, Yahaba-cho, Shiwa-gun, Iwate, 028-3694, Japan
| | - Masato Hirakawa
- Department of Anatomy (Cell Biology), Iwate Medical University, 1-1-1 Idaidori, Yahaba-cho, Shiwa-gun, Iwate, 028-3694, Japan
| | - Tomoyuki Saino
- Department of Anatomy (Cell Biology), Iwate Medical University, 1-1-1 Idaidori, Yahaba-cho, Shiwa-gun, Iwate, 028-3694, Japan
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2
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Frey A, Lunding LP, Wegmann M. The Dual Role of the Airway Epithelium in Asthma: Active Barrier and Regulator of Inflammation. Cells 2023; 12:2208. [PMID: 37759430 PMCID: PMC10526792 DOI: 10.3390/cells12182208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/01/2023] [Accepted: 09/03/2023] [Indexed: 09/29/2023] Open
Abstract
Chronic airway inflammation is the cornerstone on which bronchial asthma arises, and in turn, chronic inflammation arises from a complex interplay between environmental factors such as allergens and pathogens and immune cells as well as structural cells constituting the airway mucosa. Airway epithelial cells (AECs) are at the center of these processes. On the one hand, they represent the borderline separating the body from its environment in order to keep inner homeostasis. The airway epithelium forms a multi-tiered, self-cleaning barrier that involves an unstirred, discontinuous mucous layer, the dense and rigid mesh of the glycocalyx, and the cellular layer itself, consisting of multiple, densely interconnected cell types. On the other hand, the airway epithelium represents an immunologically highly active tissue once its barrier has been penetrated: AECs play a pivotal role in releasing protective immunoglobulin A. They express a broad spectrum of pattern recognition receptors, enabling them to react to environmental stressors that overcome the mucosal barrier. By releasing alarmins-proinflammatory and regulatory cytokines-AECs play an active role in the formation, strategic orientation, and control of the subsequent defense reaction. Consequently, the airway epithelium is of vital importance to chronic inflammatory diseases, such as asthma.
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Affiliation(s)
- Andreas Frey
- Division of Mucosal Immunology and Diagnostics, Research Center Borstel, 23845 Borstel, Germany;
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 22927 Großhansdorf, Germany;
| | - Lars P. Lunding
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 22927 Großhansdorf, Germany;
- Division of Lung Immunology, Research Center Borstel, 23845 Borstel, Germany
| | - Michael Wegmann
- Airway Research Center North (ARCN), German Center for Lung Research (DZL), 22927 Großhansdorf, Germany;
- Division of Lung Immunology, Research Center Borstel, 23845 Borstel, Germany
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3
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Seidl C, Da Silva F, Zhang K, Wohlgemuth K, Omran H, Niehrs C. Mucociliary Wnt signaling promotes cilia biogenesis and beating. Nat Commun 2023; 14:1259. [PMID: 36878953 PMCID: PMC9988884 DOI: 10.1038/s41467-023-36743-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 02/15/2023] [Indexed: 03/08/2023] Open
Abstract
It is widely thought that Wnt/Lrp6 signaling proceeds through the cytoplasm and that motile cilia are signaling-inert nanomotors. Contrasting both views, we here show in the mucociliary epidermis of X. tropicalis embryos that motile cilia transduce a ciliary Wnt signal that is distinct from canonical β-catenin signaling. Instead, it engages a Wnt-Gsk3-Ppp1r11-Pp1 signaling axis. Mucociliary Wnt signaling is essential for ciliogenesis and it engages Lrp6 co-receptors that localize to cilia via a VxP ciliary targeting sequence. Live-cell imaging using a ciliary Gsk3 biosensor reveals an immediate response of motile cilia to Wnt ligand. Wnt treatment stimulates ciliary beating in X. tropicalis embryos and primary human airway mucociliary epithelia. Moreover, Wnt treatment improves ciliary function in X. tropicalis ciliopathy models of male infertility and primary ciliary dyskinesia (ccdc108, gas2l2). We conclude that X. tropicalis motile cilia are Wnt signaling organelles that transduce a distinct Wnt-Pp1 response.
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Affiliation(s)
- Carina Seidl
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
| | - Fabio Da Silva
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
| | - Kaiqing Zhang
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
| | - Kai Wohlgemuth
- University Children's Hospital Muenster, Department of General Pediatrics, 48149, Muenster, Germany
| | - Heymut Omran
- University Children's Hospital Muenster, Department of General Pediatrics, 48149, Muenster, Germany
| | - Christof Niehrs
- Division of Molecular Embryology, DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany. .,Institute of Molecular Biology (IMB), 55128, Mainz, Germany.
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4
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Kohlfaerber T, Pieper M, Münter M, Holzhausen C, Ahrens M, Idel C, Bruchhage KL, Leichtle A, König P, Hüttmann G, Schulz-Hildebrandt H. Dynamic microscopic optical coherence tomography to visualize the morphological and functional micro-anatomy of the airways. BIOMEDICAL OPTICS EXPRESS 2022; 13:3211-3223. [PMID: 35781952 PMCID: PMC9208592 DOI: 10.1364/boe.456104] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/03/2022] [Accepted: 04/19/2022] [Indexed: 06/15/2023]
Abstract
In the imaging of airway tissue, optical coherence tomography (OCT) provides cross-sectional images of tissue structures, shows cilia movement and mucus secretion, but does not provide sufficient contrast to differentiate individual cells. By using fast sequences of microscopic resolution OCT (mOCT) images, OCT can use small signal fluctuations to overcome lack in contrast and speckle noise. In this way, OCT visualizes airway morphology on a cellular level and allows the tracking of the dynamic behavior of immune cells, as well as mucus transport and secretion. Here, we demonstrate that mOCT, by using temporal tissue fluctuation as contrast (dynamic mOCT), provides the possibility to study physiological and pathological tissue processes in vivo.
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Affiliation(s)
- Tabea Kohlfaerber
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Mario Pieper
- University of Lübeck, Institute of Anatomy, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Airway Research Center North Member of the German Center for Lung Research, DZL, 22927 Großhansdorf, Germany
| | - Michael Münter
- University of Lübeck, Institute of Biomedical Optics, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Cornelia Holzhausen
- University of Lübeck, Institute of Anatomy, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Martin Ahrens
- Airway Research Center North Member of the German Center for Lung Research, DZL, 22927 Großhansdorf, Germany
- University of Lübeck, Institute of Biomedical Optics, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Christian Idel
- University Hospital Schleswig-Holstein, ENT Clinics, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Karl-Ludwig Bruchhage
- University Hospital Schleswig-Holstein, ENT Clinics, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Anke Leichtle
- University Hospital Schleswig-Holstein, ENT Clinics, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Peter König
- University of Lübeck, Institute of Anatomy, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Airway Research Center North Member of the German Center for Lung Research, DZL, 22927 Großhansdorf, Germany
| | - Gereon Hüttmann
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- University of Lübeck, Institute of Anatomy, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Airway Research Center North Member of the German Center for Lung Research, DZL, 22927 Großhansdorf, Germany
- Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
| | - Hinnerk Schulz-Hildebrandt
- Medizinisches Laserzentrum Lübeck GmbH, Peter-Monnik-Weg 4, 23562 Lübeck, Germany
- University of Lübeck, Institute of Anatomy, Ratzeburger Allee 160, 23562 Lübeck, Germany
- Airway Research Center North Member of the German Center for Lung Research, DZL, 22927 Großhansdorf, Germany
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5
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Walentek P. Signaling Control of Mucociliary Epithelia: Stem Cells, Cell Fates, and the Plasticity of Cell Identity in Development and Disease. Cells Tissues Organs 2022; 211:736-753. [PMID: 33902038 PMCID: PMC8546001 DOI: 10.1159/000514579] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/19/2021] [Indexed: 01/25/2023] Open
Abstract
Mucociliary epithelia are composed of multiciliated, secretory, and stem cells and line various organs in vertebrates such as the respiratory tract. By means of mucociliary clearance, those epithelia provide a first line of defense against inhaled particles and pathogens. Mucociliary clearance relies on the correct composition of cell types, that is, the proper balance of ciliated and secretory cells. A failure to generate and to maintain correct cell type composition and function results in impaired clearance and high risk to infections, such as in congenital diseases (e.g., ciliopathies) as well as in acquired diseases, including asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). While it remains incompletely resolved how precisely cell types are specified and maintained in development and disease, many studies have revealed important mechanisms regarding the signaling control in mucociliary cell types in various species. Those studies not only provided insights into the signaling contribution to organ development and regeneration but also highlighted the remarkable plasticity of cell identity encountered in mucociliary maintenance, including frequent trans-differentiation events during homeostasis and specifically in disease. This review will summarize major findings and provide perspectives regarding the future of mucociliary research and the treatment of chronic airway diseases associated with tissue remodeling.
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Affiliation(s)
- Peter Walentek
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany.,CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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6
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Echinocandins Accelerate Particle Transport Velocity in the Murine Tracheal Epithelium: Dependency on Intracellular Ca 2+ Stores. Antimicrob Agents Chemother 2021; 65:e0066921. [PMID: 34491804 PMCID: PMC8522769 DOI: 10.1128/aac.00669-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The mucociliary clearance of lower airways is modulated by different physiologic stimuli and also by pathophysiologic agents like polluting substances or pharmaceutical molecules. In the present investigation, we measured the particle transport velocity (PTV) of mouse tracheae as a surrogate for mucociliary clearance. In mouse tracheal preparations, we detected a sustained increase in the PTV under the application of the echinocandins caspofungin, anidulafungin, and micafungin. In further experiments, we observed the effects of echinocandins on the PTV were dependent on intracellular Ca2+ homeostasis. In Ca2+-free buffer solutions, the amplitude of the echinocandin-evoked rise in the PTV was significantly reduced relative to that in the experiments in Ca2+-containing solutions. Depletion of intracellular Ca2+ stores of the endoplasmic reticulum (ER) by caffeine completely prevented an increase in the PTV with subsequent caspofungin applications. Mitochondrial Ca2+ stores seemed to be unaffected by echinocandin treatment. We also observed no altered generation of reactive oxygen species under the application of echinocandins as probable mediators of the PTV. Consequently, the observed echinocandin effects on the PTV depend upon the Ca2+ influx and Ca2+ contents of the ER. We assume that all three echinocandins act intracellularly on ER Ca2+ stores to activate Ca2+-dependent signal transduction cascades, enhancing the PTV.
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7
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Arzola-Martínez L, Benavente R, Vega G, Ríos M, Fonseca W, Rasky AJ, Morris S, Lukacs NW, Villalón MJ. Blocking ATP-releasing channels prevents high extracellular ATP levels and airway hyperreactivity in an asthmatic mouse model. Am J Physiol Lung Cell Mol Physiol 2021; 321:L466-L476. [PMID: 34231389 DOI: 10.1152/ajplung.00450.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Allergic asthma is a chronic airway inflammatory response to different triggers like inhaled allergens. Excessive ATP in fluids from patients with asthma is considered an inflammatory signal and an important autocrine/paracrine modulator of airway physiology. Here, we investigated the deleterious effect of increased extracellular ATP (eATP) concentration on the mucociliary clearance (MCC) effectiveness and determined the role of ATP releasing channels during airway inflammation in an ovalbumin (OVA)-sensitized mouse model. Our allergic mouse model exhibited high levels of eATP measured in the tracheal fluid with a luciferin-luciferase assay and reduced MCC velocity determined by microspheres tracking in the trachea ex vivo. Addition of ATP had a dual effect on MCC, where lower ATP concentration (µM) increased microspheres velocity, whereas higher concentration (mM) transiently stopped microspheres movement. Also, an augmented ethidium bromide uptake by the allergic tracheal airway epithelium suggests an increase in ATP release channel functionality during inflammatory conditions. The use of carbenoxolone, a nonspecific inhibitor of connexin and pannexin1 channels reduced the eATP concentration in the allergic mouse tracheal fluid and dye uptake by the airway epithelium, providing evidence that these ATP release channels are facilitating the net flux of ATP to the lumen during airway inflammation. However, only the specific inhibition of pannexin1 with 10Panx peptide significantly reduced eATP in bronchoalveolar lavage and decreased airway hyperresponsiveness in OVA-allergic mouse model. These data provide evidence that blocking eATP may be a pharmacological alternative to be explored in rescue therapy during episodes of airflow restriction in patients with asthma.
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Affiliation(s)
- Llilian Arzola-Martínez
- Department of Physiology, Faculty of Biological Science, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Rebeca Benavente
- Department of Physiology, Faculty of Biological Science, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Génesis Vega
- Department of Physiology, Faculty of Biological Science, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mariana Ríos
- Department of Molecular Genetics and Microbiology, Faculty of Biological Science, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Wendy Fonseca
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Andrew J Rasky
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Susan Morris
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Nicholas W Lukacs
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Manuel J Villalón
- Department of Physiology, Faculty of Biological Science, Pontificia Universidad Católica de Chile, Santiago, Chile
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Marinković M, Berger J, Jékely G. Neuronal coordination of motile cilia in locomotion and feeding. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190165. [PMID: 31884921 PMCID: PMC7017327 DOI: 10.1098/rstb.2019.0165] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Efficient ciliary locomotion and transport require the coordination of motile cilia. Short-range coordination of ciliary beats can occur by biophysical mechanisms. Long-range coordination across large or disjointed ciliated fields often requires nervous system control and innervation of ciliated cells by ciliomotor neurons. The neuronal control of cilia is best understood in invertebrate ciliated microswimmers, but similar mechanisms may operate in the vertebrate body. Here, we review how the study of aquatic invertebrates contributed to our understanding of the neuronal control of cilia. We summarize the anatomy of ciliomotor systems and the physiological mechanisms that can alter ciliary activity. We also discuss the most well-characterized ciliomotor system, that of the larval annelid Platynereis. Here, pacemaker neurons drive the rhythmic activation of cholinergic and serotonergic ciliomotor neurons to induce ciliary arrests and beating. The Platynereis ciliomotor neurons form a distinct part of the larval nervous system. Similar ciliomotor systems likely operate in other ciliated larvae, such as mollusc veligers. We discuss the possible ancestry and conservation of ciliomotor circuits and highlight how comparative experimental approaches could contribute to a better understanding of the evolution and function of ciliary systems. This article is part of the Theo Murphy meeting issue ‘Unity and diversity of cilia in locomotion and transport’.
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Affiliation(s)
- Milena Marinković
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Jürgen Berger
- Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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9
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Hollenhorst MI, Jurastow I, Nandigama R, Appenzeller S, Li L, Vogel J, Wiederhold S, Althaus M, Empting M, Altmüller J, Hirsch AKH, Flockerzi V, Canning BJ, Saliba A, Krasteva‐Christ G. Tracheal brush cells release acetylcholine in response to bitter tastants for paracrine and autocrine signaling. FASEB J 2019; 34:316-332. [DOI: 10.1096/fj.201901314rr] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/20/2019] [Accepted: 10/22/2019] [Indexed: 12/20/2022]
Affiliation(s)
| | - Innokentij Jurastow
- Institute of Anatomy and Cell Biology Justus‐Liebig‐University of Giessen Giessen Germany
- Department of Anesthesiology and Intensive Care Medicine (CS) University Hospital Charité Humboldt University of Berlin Berlin Germany
| | - Rajender Nandigama
- Institute of Anatomy and Cell Biology University of Würzburg Würzburg Germany
| | - Silke Appenzeller
- Comprehensive Cancer Centre Mainfranken University of Würzburg Würzburg Germany
| | - Lei Li
- Core Unit SysMed University of Würzburg Würzburg Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA‐based Infection Research (HIRI) Helmholtz‐Centre for Infection Research (HZI) Würzburg Germany
| | - Stephanie Wiederhold
- Institute of Anatomy and Cell Biology Justus‐Liebig‐University of Giessen Giessen Germany
| | - Mike Althaus
- School of Natural and Environmental Sciences Newcastle University Newcastle upon Tyne United Kingdom
| | - Martin Empting
- Department of Drug Design and Optimization (DDOP) Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS)‐Helmholtz Centre for Infection Research (HZI) Saarbrücken Germany
- Department of Pharmacy Saarland University Saarbrücken Germany
- German Centre for Infection Research (DZIF) Saarbrücken Germany
| | - Janine Altmüller
- Cologne Centre for Genomics University of Cologne Cologne Germany
| | - Anna K. H. Hirsch
- Department of Drug Design and Optimization (DDOP) Helmholtz‐Institute for Pharmaceutical Research Saarland (HIPS)‐Helmholtz Centre for Infection Research (HZI) Saarbrücken Germany
- Department of Pharmacy Saarland University Saarbrücken Germany
- German Centre for Infection Research (DZIF) Saarbrücken Germany
| | - Veit Flockerzi
- Institute of Experimental and Clinical Pharmacology and Toxicology/PZMS Saarland University Homburg Germany
| | - Brendan J. Canning
- Department of Medicine Division of Allergy and Clinical Immunology School of Medicine Johns Hopkins University Baltimore MD USA
| | - Antoine‐Emmanuel Saliba
- Helmholtz Institute for RNA‐based Infection Research (HIRI) Helmholtz‐Centre for Infection Research (HZI) Würzburg Germany
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10
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Mucociliary Clearance in Mice Measured by Tracking Trans-tracheal Fluorescence of Nasally Aerosolized Beads. Sci Rep 2018; 8:14744. [PMID: 30282981 PMCID: PMC6170422 DOI: 10.1038/s41598-018-33053-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/19/2018] [Indexed: 12/15/2022] Open
Abstract
Mucociliary clearance (MCC) is the first line of defense in clearing airways. In genetically engineered mice, each component of this system (ciliary beat, mucus, airway surface hydration) can be studied separately to determine its contribution to MCC. Because MCC is difficult to measure in mice, MCC measurements are often omitted from these studies. We report a simple method to measure MCC in mice involving nasal inhalation of aerosolized fluorescent beads and trans-tracheal bead tracking. This method has a number of advantages over existing methods: (1) a small volume of liquid is deposited thus minimally disturbing the airway surface; (2) bead behavior on airways can be visualized; (3) useful for adult or neonatal mice; (4) the equipment is relatively inexpensive and easily obtainable. The type of anesthetic had no significant effect on the rate of MCC, but overloading the airways with beads significantly decreased MCC. In addition, the rate of bead transport was not different in alive (3.11 mm/min) vs recently euthanized mice (3.10 mm/min). A 5-min aerosolization of beads in a solution containing UTP significantly increased the rate of MCC, demonstrating that our method would be of value in testing the role of various pharmacological agents on MCC.
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11
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Hull J, Lyon R. In vitro pharmacology of ambroxol: Potential serotonergic sites of action. Life Sci 2018; 197:67-72. [DOI: 10.1016/j.lfs.2018.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/19/2018] [Accepted: 02/02/2018] [Indexed: 12/19/2022]
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12
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Chortarea S, Barosova H, Clift MJD, Wick P, Petri-Fink A, Rothen-Rutishauser B. Human Asthmatic Bronchial Cells Are More Susceptible to Subchronic Repeated Exposures of Aerosolized Carbon Nanotubes At Occupationally Relevant Doses Than Healthy Cells. ACS NANO 2017; 11:7615-7625. [PMID: 28505409 DOI: 10.1021/acsnano.7b01992] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although acute pulmonary toxicity of carbon nanotubes (CNTs) has been extensively investigated, the knowledge of potential health effects following chronic occupational exposure is currently limited and based only upon in vivo approaches. Our aim was to realistically mimic subchronic inhalation of multiwalled CNTs (MWCNTs) in vitro, using the air-liquid interface cell exposure (ALICE) system for aerosol exposures on reconstituted human bronchial tissue from healthy and asthmatic donors. The reliability and sensitivity of the system were validated using crystalline quartz (DQ12), which elicited an increased (pro-)inflammatory response, as reported in vivo. At the administrated MWCNT doses relevant to human occupational lifetime exposure (10 μg/cm2 for 5 weeks of repeated exposures/5 days per week) elevated cilia beating frequency (in both epithelial cultures), and mucociliary clearance (in asthmatic cells only) occurred, whereas no cytotoxic reactions or morphological changes were observed. However, chronic MWCNT exposure did induce an evident (pro-)inflammatory and oxidative stress response in both healthy and asthmatic cells. The latter revealed stronger and more durable long-term effects compared to healthy cells, indicating that individuals with asthma may be more susceptible to adverse effects from chronic MWCNT exposure. Our results highlight the power of occupationally relevant subchronic exposures on human in vitro models in nanosafety hazard assessment.
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Affiliation(s)
- Savvina Chortarea
- BioNanomaterials, Adolphe Merkle Institute, University of Fribourg , CH-1700 Fribourg, Switzerland
| | - Hana Barosova
- BioNanomaterials, Adolphe Merkle Institute, University of Fribourg , CH-1700 Fribourg, Switzerland
| | | | - Peter Wick
- Laboratory for Materials-Biology Interactions, Empa, Swiss Federal Laboratories for Materials, Science and Technology , 9014 St Gallen, Switzerland
| | - Alke Petri-Fink
- BioNanomaterials, Adolphe Merkle Institute, University of Fribourg , CH-1700 Fribourg, Switzerland
- Department of Chemistry, University of Fribourg , CH-1700 Fribourg, Switzerland
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13
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Verasztó C, Ueda N, Bezares-Calderón LA, Panzera A, Williams EA, Shahidi R, Jékely G. Ciliomotor circuitry underlying whole-body coordination of ciliary activity in the Platynereis larva. eLife 2017; 6. [PMID: 28508746 PMCID: PMC5531833 DOI: 10.7554/elife.26000] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/14/2017] [Indexed: 01/23/2023] Open
Abstract
Ciliated surfaces harbouring synchronously beating cilia can generate fluid flow or drive locomotion. In ciliary swimmers, ciliary beating, arrests, and changes in beat frequency are often coordinated across extended or discontinuous surfaces. To understand how such coordination is achieved, we studied the ciliated larvae of Platynereis dumerilii, a marine annelid. Platynereis larvae have segmental multiciliated cells that regularly display spontaneous coordinated ciliary arrests. We used whole-body connectomics, activity imaging, transgenesis, and neuron ablation to characterize the ciliomotor circuitry. We identified cholinergic, serotonergic, and catecholaminergic ciliomotor neurons. The synchronous rhythmic activation of cholinergic cells drives the coordinated arrests of all cilia. The serotonergic cells are active when cilia are beating. Serotonin inhibits the cholinergic rhythm, and increases ciliary beat frequency. Based on their connectivity and alternating activity, the catecholaminergic cells may generate the rhythm. The ciliomotor circuitry thus constitutes a stop-and-go pacemaker system for the whole-body coordination of ciliary locomotion. DOI:http://dx.doi.org/10.7554/eLife.26000.001 The oceans contain a wide variety of microscopic organisms including bacteria, algae and animal larvae. Many of the microscopic animals that live in water use thousands of beating hair-like projections called cilia instead of muscles to swim around in the water. Understanding how these animals move will aid our understanding of how ocean processes, such as the daily migration of plankton to and from the surface of the water, are regulated. The larvae of a ragworm called Platynereis use cilia to move around. Like other animals, Platynereis has a nervous system containing neurons that form networks to control the body. It is possible that the nervous system is involved in coordinating the activity of the cilia to allow the larvae to manoeuvre in the water, but it was not clear how this could work. Here, Veraszto et al. investigated how Platynereis is able to swim. The experiments show that the larvae can coordinate their cilia so that they all stop beating at the same time and fold into to the body. Then the larvae can stimulate all of their cilia to resume beating. Veraszto et al. used a technique called electron microscopy to study how the nervous system connects to the cilia. This revealed that several giant neurons span the entire length of the larva and connect to cells that bear cilia. When these neurons were active, all the cilia in the body closed. When a different group of neurons in the larva was active, all of the cilia resumed beating. Together, these two groups of neurons were ultimately responsible for the swimming motions of the larvae. Together, the findings of Veraszto et al. show that a few neurons in the nervous system of the larvae provide a sophisticated system for controlling how the larvae swim around. This suggests that the microscopic animals found in marine environments are a lot more sophisticated than previously appreciated. A next challenge is to find out how the neurons that control cilia connect to the rest of the animal’s nervous system and how different cues influence when the larva swims or stops swimming. This would help us understand how the environment influences the distribution of animal larvae in the oceans and how this may change in the future. DOI:http://dx.doi.org/10.7554/eLife.26000.002
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Affiliation(s)
- Csaba Verasztó
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Nobuo Ueda
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Aurora Panzera
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Réza Shahidi
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany
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14
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Lindner K, Ströbele M, Schlick S, Webering S, Jenckel A, Kopf J, Danov O, Sewald K, Buj C, Creutzenberg O, Tillmann T, Pohlmann G, Ernst H, Ziemann C, Hüttmann G, Heine H, Bockhorn H, Hansen T, König P, Fehrenbach H. Biological effects of carbon black nanoparticles are changed by surface coating with polycyclic aromatic hydrocarbons. Part Fibre Toxicol 2017; 14:8. [PMID: 28327162 PMCID: PMC5361723 DOI: 10.1186/s12989-017-0189-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/07/2017] [Indexed: 02/04/2023] Open
Abstract
Background Carbon black nanoparticles (CBNP) are mainly composed of carbon, with a small amount of other elements (including hydrogen and oxygen). The toxicity of CBNP has been attributed to their large surface area, and through adsorbing intrinsically toxic substances, such as polycyclic aromatic hydrocarbons (PAH). It is not clear whether a PAH surface coating changes the toxicological properties of CBNP by influencing their physicochemical properties, through the specific toxicity of the surface-bound PAH, or by a combination of both. Methods Printex®90 (P90) was used as CBNP; the comparators were P90 coated with either benzo[a]pyrene (BaP) or 9-nitroanthracene (9NA), and soot from acetylene combustion that bears various PAHs on the surface (AS-PAH). Oxidative stress and IL-8/KC mRNA expression were determined in A549 and bronchial epithelial cells (16HBE14o-, Calu-3), mouse intrapulmonary airways and tracheal epithelial cells. Overall toxicity was tested in a rat inhalation study according to Organization for Economic Co-operation and Development (OECD) criteria. Effects on cytochrome monooxygenase (Cyp) mRNA expression, cell viability and mucociliary clearance were determined in acute exposure models using explanted murine trachea. Results All particles had similar primary particle size, shape, hydrodynamic diameter and ζ-potential. All PAH-containing particles had a comparable specific surface area that was approximately one third that of P90. AS-PAH contained a mixture of PAH with expected higher toxicity than BaP or 9NA. PAH-coating reduced some effects of P90 such as IL-8 mRNA expression and oxidative stress in A549 cells, granulocyte influx in the in vivo OECD experiment, and agglomeration of P90 and mucus release in the murine trachea ex vivo. Furthermore, P90-BaP decreased particle transport speed compared to P90 at 10 μg/ml. In contrast, PAH-coating induced IL-8 mRNA expression in bronchial epithelial cell lines, and Cyp mRNA expression and apoptosis in tracheal epithelial cells. In line with the higher toxicity compared to P90-BaP and P90-9NA, AS-PAH had the strongest biological effects both ex vivo and in vivo. Conclusions Our results demonstrate that the biological effect of CBNP is determined by a combination of specific surface area and surface-bound PAH, and varies in different target cells. Electronic supplementary material The online version of this article (doi:10.1186/s12989-017-0189-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karina Lindner
- Institut für Anatomie, Zentrum für medizinische Struktur- und Zellbiologie, Universität zu Lübeck (UzL), Airway Research Center North (ARCN), German Center for Lung Research (DZL), Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Michael Ströbele
- Karlsruher Institut für Technologie, Engler-Bunte-Institut, Bereich Verbrennungstechnik, Karlsruhe, Germany
| | - Sandra Schlick
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Experimentelle Pneumologie, Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - Sina Webering
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Experimentelle Pneumologie, Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - André Jenckel
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Angeborene Immunität, Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - Johannes Kopf
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Olga Danov
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Katherina Sewald
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Christian Buj
- Institut für Biomedizinische Optik, Universität zu Lübeck (UzL), Lübeck, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Lübeck, Germany
| | - Otto Creutzenberg
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Thomas Tillmann
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Gerhard Pohlmann
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Heinrich Ernst
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Christina Ziemann
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Gereon Hüttmann
- Institut für Biomedizinische Optik, Universität zu Lübeck (UzL), Lübeck, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Lübeck, Germany
| | - Holger Heine
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Angeborene Immunität, Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
| | - Henning Bockhorn
- Karlsruher Institut für Technologie, Engler-Bunte-Institut, Bereich Verbrennungstechnik, Karlsruhe, Germany
| | - Tanja Hansen
- Fraunhofer Institut für Toxikologie und Experimentelle Medizin ITEM, Hannover, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany
| | - Peter König
- Institut für Anatomie, Zentrum für medizinische Struktur- und Zellbiologie, Universität zu Lübeck (UzL), Airway Research Center North (ARCN), German Center for Lung Research (DZL), Ratzeburger Allee 160, 23562, Lübeck, Germany.
| | - Heinz Fehrenbach
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Experimentelle Pneumologie, Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany
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15
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Braun K, Stach T. Comparative study of serotonin-like immunoreactivity in the branchial basket, digestive tract, and nervous system in tunicates. ZOOMORPHOLOGY 2016. [DOI: 10.1007/s00435-016-0317-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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16
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Weiterer S, Kohlen T, Veit F, Sachs L, Uhle F, Lichtenstern C, Weigand MA, Henrich M. Galactomannan and Zymosan Block the Epinephrine-Induced Particle Transport in Tracheal Epithelium. PLoS One 2015; 10:e0143163. [PMID: 26571499 PMCID: PMC4646458 DOI: 10.1371/journal.pone.0143163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 11/02/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Ciliary beating by respiratory epithelial cells continuously purges pathogens from the lower airways. Here we investigated the effect of the fungal cell wall polysaccharides Galactomannan (GM) and Zymosan (Zym) on the adrenergic activated particle transport velocity (PTV) of tracheal epithelium. METHODS Experiments were performed using tracheae isolated from male C57BL/6J mice. Transport velocity of the cilia bearing epithelial cells was measured by analysing recorded image sequences. Generation of reactive oxygen species (ROS) were determined using Amplex Red reagents. PCR experiments were performed on isolated tracheal epithelium to identify adrenergic receptor mRNA. RESULTS The adrenergic receptors α1D, α2A, β1 and β2 have been identified in isolated tracheal epithelium. We found epinephrine responsible for an increase in PTV, which could only be reduced by selective β-receptor-inhibition. In addition, either GM or Zym prevented the epinephrine induced PTV increase. Furthermore, we observed a strong ROS generation evoked by GM or Zym. However, epinephrine induced increase in PTV recovered in the presence of GM and Zym after application of ROS scavengers. CONCLUSION Both GM or Zym trigger reversible ROS generation in tracheal tissue leading to inhibition of the β-adrenergic increase in PTV.
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Affiliation(s)
- Sebastian Weiterer
- Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany
- * E-mail:
| | - Thomas Kohlen
- Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Florian Veit
- Excellencecluster Cardio-Pulmonary System (ECCPS), German Lung Center (DZL), Universities of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig-University Giessen, Giessen, Germany
| | - Lydia Sachs
- Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Florian Uhle
- Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany
| | | | - Markus A. Weigand
- Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Michael Henrich
- Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University Giessen, Giessen, Germany
- Department of Anaesthesiology and Intensive Care Medicine, St. Vincentius-Clinic, Karlsruhe, Germany
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17
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Walentek P, Beyer T, Hagenlocher C, Müller C, Feistel K, Schweickert A, Harland RM, Blum M. ATP4a is required for development and function of the Xenopus mucociliary epidermis - a potential model to study proton pump inhibitor-associated pneumonia. Dev Biol 2015; 408:292-304. [PMID: 25848696 DOI: 10.1016/j.ydbio.2015.03.013] [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: 10/04/2014] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 12/12/2022]
Abstract
Proton pump inhibitors (PPIs), which target gastric H(+)/K(+)ATPase (ATP4), are among the most commonly prescribed drugs. PPIs are used to treat ulcers and as a preventative measure against gastroesophageal reflux disease in hospitalized patients. PPI treatment correlates with an increased risk for airway infections, i.e. community- and hospital-acquired pneumonia. The cause for this correlation, however, remains elusive. The Xenopus embryonic epidermis is increasingly being used as a model to study airway-like mucociliary epithelia. Here we use this model to address how ATP4 inhibition may affect epithelial function in human airways. We demonstrate that atp4a knockdown interfered with the generation of cilia-driven extracellular fluid flow. ATP4a and canonical Wnt signaling were required in the epidermis for expression of foxj1, a transcriptional regulator of motile ciliogenesis. The ATP4/Wnt module activated foxj1 downstream of ciliated cell fate specification. In multiciliated cells (MCCs) of the epidermis, ATP4a was also necessary for normal myb expression, apical actin formation, basal body docking and alignment of basal bodies. Furthermore, ATP4-dependent Wnt/β-catenin signaling in the epidermis was a prerequisite for foxa1-mediated specification of small secretory cells (SSCs). SSCs release serotonin and other substances into the medium, and thereby regulate ciliary beating in MCCs and protect the epithelium against infection. Pharmacological inhibition of ATP4 in the mature mucociliary epithelium also caused a loss of MCCs and led to impaired mucociliary clearance. These data strongly suggest that PPI-associated pneumonia in human patients might, at least in part, be linked to dysfunction of mucociliary epithelia of the airways.
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Affiliation(s)
- Peter Walentek
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany; Department of Molecular and Cell Biology, Center for Integrative Genomics, University of California at Berkeley, Berkeley, CA 94720, USA.
| | - Tina Beyer
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany
| | - Cathrin Hagenlocher
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany
| | - Christina Müller
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany
| | - Kerstin Feistel
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany
| | - Axel Schweickert
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany
| | - Richard M Harland
- Department of Molecular and Cell Biology, Center for Integrative Genomics, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Martin Blum
- Institute of Zoology, University of Hohenheim, Garbenstrasse 30, 70593 Stuttgart, Germany
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18
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Huang BK, Choma MA. Microscale imaging of cilia-driven fluid flow. Cell Mol Life Sci 2015; 72:1095-113. [PMID: 25417211 PMCID: PMC4605231 DOI: 10.1007/s00018-014-1784-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 10/24/2022]
Abstract
Cilia-driven fluid flow is important for multiple processes in the body, including respiratory mucus clearance, gamete transport in the oviduct, right-left patterning in the embryonic node, and cerebrospinal fluid circulation. Multiple imaging techniques have been applied toward quantifying ciliary flow. Here, we review common velocimetry methods of quantifying fluid flow. We then discuss four important optical modalities, including light microscopy, epifluorescence, confocal microscopy, and optical coherence tomography, that have been used to investigate cilia-driven flow.
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Affiliation(s)
- Brendan K Huang
- Department of Biomedical Engineering, Yale University, New Haven, USA,
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19
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Bermbach S, Weinhold K, Roeder T, Petersen F, Kugler C, Goldmann T, Rupp J, König P. Mechanisms of cilia-driven transport in the airways in the absence of mucus. Am J Respir Cell Mol Biol 2014; 51:56-67. [PMID: 24467665 DOI: 10.1165/rcmb.2012-0530oc] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Airway mucus is thought to be required for the clearance of inhaled particles by mucociliary transport, but this view has recently been challenged. To test if mucus is necessary for cilia-driven particle transport, we removed mucus from murine and human ex vivo airway preparations by thorough rinsing with buffer with or without additional dithiothreitol washing. The transport of particles with diameters of 4.5 μm, 200 nm, and 40 nm and of bacteria was analyzed by video microscopy. Complete removal of mucus was verified by wheat germ agglutinin staining and by scanning electron microscopy. In the absence of mucus, we observed efficient transport of particles and bacteria by direct cilia-mediated propulsion or via fluid flow generated by ciliary beating. Virus-sized particles had the tendency to attach to cilia. Because direct contact of particles with ciliated cells occurs in the absence of mucus, we examined if this direct interaction changes epithelial function. Neither bacteria- nor LPS-induced nuclear translocation of NF-κB p65 in ciliated cells occurred, indicating that mere contact between ciliated cells and bacteria during transport does not activate the epithelium. Attachment of virus-sized particles to cilia could induce mucus release and/or increase the ciliary beat frequency. Our results indicate that cilia-driven transport of particles with various sizes is possible in murine and human airways without the presence of mucus. If mucus-free transport fails, the epithelium can react by releasing mucus or increasing the ciliary beat frequency to maintain particle transport.
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Affiliation(s)
- Saskia Bermbach
- 1 Institut für Anatomie, Zentrum für medizinische Struktur- und Zellbiologie, Universität zu Lübeck, Lübeck, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), Germany
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20
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Weiterer S, Schulte D, Müller S, Kohlen T, Uhle F, Weigand MA, Henrich M. Tumor necrosis factor alpha induces a serotonin dependent early increase in ciliary beat frequency and epithelial transport velocity in murine tracheae. PLoS One 2014; 9:e91705. [PMID: 24626175 PMCID: PMC3953516 DOI: 10.1371/journal.pone.0091705] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 02/14/2014] [Indexed: 12/21/2022] Open
Abstract
The tracheal epithelium prevents via its highly effective clearance mechanism the contamination of the lower airways by pathogens. This mechanism is driven by ciliary bearing cells which are not only in contact with the gas phase; in addition they are also influenced by inflammatory mediators. These mediators can alter the protective function of the epithelium. Since the pro-inflammatoric cytokine tumor necrosis factor-α (TNF-α) plays a pivotal role within the inflammatory cascade, we investigated its effect onto the tracheal epithelium measured by its ciliary beat frequency and the particle transport velocity. In organ explant experiments the ciliary beat frequency and the particle transport velocity were measured under the application of TNF-α using tracheae from male C57BL6J mice. We observed a dose dependent TNF-α induced increase of both particle transport velocity and ciliary beat frequency. Knock out mice experiments made evident that the increase was depended on the expression of tumor necrosis factor receptor 1 (TNF-R1). The increases in ciliary beat frequency as well as the accelerated particle transport velocity were either inhibited by the unspecific serotonin antagonist methysergide or by cyproheptadine a specific 5-HT2 receptor antagonist. Thus, acetylcholine antagonists or nitric oxide synthase (NOS) inhibitors failed to inhibit the TNF-α induced activation. In conclusion, TNF-α may play a pivotal role in the protection of lower airways by inducing ciliary activity and increase in particle transport velocity via TNF-R1 and 5-HT2 receptor.
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Affiliation(s)
- Sebastian Weiterer
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
| | - Dagmar Schulte
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
| | - Sabrina Müller
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
| | - Thomas Kohlen
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
| | - Florian Uhle
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
| | - Markus A. Weigand
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
| | - Michael Henrich
- Department of Anaesthesiology, Intensive Care Medicine, Pain Therapy, Justus-Liebig-University Giessen, Giessen, Germany
- * E-mail:
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21
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Walentek P, Bogusch S, Thumberger T, Vick P, Dubaissi E, Beyer T, Blum M, Schweickert A. A novel serotonin-secreting cell type regulates ciliary motility in the mucociliary epidermis of Xenopus tadpoles. Development 2014; 141:1526-33. [PMID: 24598162 DOI: 10.1242/dev.102343] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The embryonic skin of Xenopus tadpoles serves as an experimental model system for mucociliary epithelia (MCE) such as the human airway epithelium. MCEs are characterized by the presence of mucus-secreting goblet and multiciliated cells (MCCs). A third cell type, ion-secreting cells (ISCs), is present in the larval skin as well. Synchronized beating of MCC cilia is required for directional transport of mucus. Here we describe a novel cell type in the Xenopus laevis larval epidermis, characterized by serotonin synthesis and secretion. It is termed small secretory cell (SSC). SSCs are detectable at early tadpole stages, unlike MCCs and ISCs, which are specified at early neurulation. Subcellularly, serotonin was found in large, apically localized vesicle-like structures, which were entirely shed into the surrounding medium. Pharmacological inhibition of serotonin synthesis decreased the velocity of cilia-driven fluid flow across the skin epithelium. This effect was mediated by serotonin type 3 receptor (Htr3), which was expressed in ciliated cells. Knockdown of Htr3 compromised flow velocity by reducing the ciliary motility of MCCs. SSCs thus represent a distinct and novel entity of the frog tadpole MCE, required for ciliary beating and mucus transport across the larval skin. The identification and characterization of SSCs consolidates the value of the Xenopus embryonic skin as a model system for human MCEs, which have been known for serotonin-dependent regulation of ciliary beat frequency.
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Affiliation(s)
- Peter Walentek
- University of Hohenheim, Institute of Zoology, Garbenstrasse 30, D-70593 Stuttgart, Germany
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22
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Currie KW, Pearson BJ. Transcription factors lhx1/5-1 and pitx are required for the maintenance and regeneration of serotonergic neurons in planarians. Development 2013; 140:3577-88. [PMID: 23903188 DOI: 10.1242/dev.098590] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In contrast to most adult organisms, freshwater planarians can regenerate any injured body part, including their entire nervous system. This allows for the analysis of genes required for both the maintenance and regeneration of specific neural subtypes. In addition, the loss of specific neural subtypes may uncover previously unknown behavioral roles for that neural population in the context of the adult animal. Here we show that two homeodomain transcription factor homologs, Smed-lhx1/5-1 and Smed-pitx, are required for the maintenance and regeneration of serotonergic neurons in planarians. When either lhx1/5-1 or pitx was knocked down by RNA interference, the expression of multiple canonical markers for serotonergic neurons was lost. Surprisingly, the loss of serotonergic function uncovered a role for these neurons in the coordination of motile cilia on the ventral epidermis of planarians that are required for their nonmuscular gliding locomotion. Finally, we show that in addition to its requirement in serotonergic neurons, Smed-pitx is required for proper midline patterning during regeneration, when it is required for the expression of the midline-organizing molecules Smed-slit in the anterior and Smed-wnt1 in the posterior.
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Affiliation(s)
- Ko W Currie
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, Canada
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Murphy SR, Schelegle ES, Miller LA, Hyde DM, Van Winkle LS. Ozone exposure alters serotonin and serotonin receptor expression in the developing lung. Toxicol Sci 2013; 134:168-79. [PMID: 23570994 DOI: 10.1093/toxsci/kft090] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ozone, a pervasive environmental pollutant, adversely affects functional lung growth in children. Animal studies demonstrate that altered lung development is associated with modified signaling within the airway epithelial mesenchymal trophic unit, including mediators that can change nerve growth. We hypothesized that ozone exposure alters the normal pattern of serotonin, its transporter (5-HTT), and two key receptors (5-HT2A and 5-HT4), a pathway involved in postnatal airway neural, epithelial, and immune processes. We exposed monkeys to acute or episodic ozone during the first 2 or 6 months of life. There were three exposure groups/age: (1) filtered air, (2) acute ozone challenge, and (3) episodic ozone + acute ozone challenge. Lungs were prepared for compartment-specific qRT-PCR, immunohistochemistry, and stereology. Airway epithelial serotonin immunopositive staining increased in all exposure groups with the most prominent in 2-month midlevel and 6-month distal airways. Gene expression of 5-HTT, 5-HT2AR, and 5-HT4R increased in an age-dependent manner. Overall expression was greater in distal compared with midlevel airways. Ozone exposure disrupted both 5-HT2AR and 5-HT4R protein expression in airways and enhanced immunopositive staining for 5-HT2AR (2 months) and 5-HT4R (6 months) on smooth muscle. Ozone exposure increases serotonin in airway epithelium regardless of airway level, age, and exposure history and changes the spatial pattern of serotonin receptor protein (5-HT2A and 5-HT4) and 5-HTT gene expression depending on compartment, age, and exposure history. Understanding how serotonin modulates components of reversible airway obstruction exacerbated by ozone exposure sets the foundation for developing clinically relevant therapies for airway disease.
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Affiliation(s)
- Shannon R Murphy
- Center for Health and the Environment, California National Primate Research Center, Davis, CA, USA
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Lavinka PC, Dong X. Molecular signaling and targets from itch: lessons for cough. COUGH 2013; 9:8. [PMID: 23497684 PMCID: PMC3630061 DOI: 10.1186/1745-9974-9-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 02/08/2013] [Indexed: 01/05/2023]
Abstract
Itch is described as an unpleasant sensation that elicits the desire to scratch, which results in the removal of the irritant from the skin. The cough reflex also results from irritation, with the purpose of removing said irritant from the airway. Could cough then be similar to itch? Anatomically, both pathways are mediated by small-diameter sensory fibers. These cough and itch sensory fibers release neuropeptides upon activation, which leads to inflammation of the nerves. Both cough and itch also involve mast cells and their mediators, which are released upon degranulation. This common inflammation and interaction with mast cells are involved in the development of chronic conditions of itch and cough. In this review, we examine the anatomy and molecular mechanisms of itch and compare them to known mechanisms for cough. Highlighting the common aspects of itch and cough could lead to new thoughts and perspectives in both fields.
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Affiliation(s)
- Pamela Colleen Lavinka
- The Solomon H, Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, 725 N Wolfe Street, Baltimore, MD, 21205, USA.
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Hussong J, Lindken R, Faulhammer P, Noreikat K, Sharp KV, Kummer W, Westerweel J. Cilia-driven particle and fluid transport over mucus-free mice tracheae. J Biomech 2012; 46:593-8. [PMID: 23276626 DOI: 10.1016/j.jbiomech.2012.08.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 07/17/2012] [Accepted: 08/09/2012] [Indexed: 11/18/2022]
Abstract
To date, there is only a fragmentary understanding of the fundamental mechanisms of airway mucociliary transport. Application of the latest measurement techniques can aid in deciphering the complex interplay between ciliary beat and airway surface liquid (ASL) transport. In the present study, direct, quasi-simultaneous measurements of the cilia-induced fluid and bead transport were performed to gain a better insight into both transport mechanisms. In this study cilia-induced periciliary liquid (PCL) transport is measured by means of micro Particle Image Velocimetry (μPIV) with neutrally buoyant tracers. Particle Tracking Velocimetry (PTV) with heavier polystyrene-ferrite beads is performed to simulate particle transport. Contrary to recent literature, in which the presence of mucus was deemed necessary to maintain periciliary liquid (PCL) transport, effective particle and fluid transport was measured in our experiments in the absence of mucus. In response to muscarine or ATP stimulation, maximum fluid transport rates of 250 μm/s at 15 μm distance to the tracheal epithelia were measured while bead transport rates over the epithelia surfaces reached 200 μm/s. We estimated that the mean bead transport is dominated by viscous drag compared to inertial fluid forces. Furthermore, mean bead transport velocities appear to be two orders of magnitude larger compared to bead sedimentation velocities. Therefore, beads are expected to closely follow the mean PCL flow in non-ciliated epithelium regions. Based on our results, we have shown that PCL transport can be directly driven by the cilia beat and that the PCL motion may be capable of driving bead transport by fluid drag.
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Affiliation(s)
- J Hussong
- Institute for Thermo- and Fluiddynamics, Universitätsstraße 150, 44801 Bochum, Germany.
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26
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Neuronal control of pedal sole cilia in the pond snail Lymnaea stagnalis appressa. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 199:71-86. [DOI: 10.1007/s00359-012-0770-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 10/11/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
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Krasteva G, Canning B, Papadakis T, Kummer W. Cholinergic brush cells in the trachea mediate respiratory responses to quorum sensing molecules. Life Sci 2012; 91:992-6. [DOI: 10.1016/j.lfs.2012.06.014] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 06/12/2012] [Accepted: 06/14/2012] [Indexed: 02/02/2023]
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28
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Noreikat K, Wolff M, Kummer W, Kölle S. Ciliary activity in the oviduct of cycling, pregnant, and muscarinic receptor knockout mice. Biol Reprod 2012; 86:120. [PMID: 22302687 DOI: 10.1095/biolreprod.111.096339] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The transport of the oocyte and the embryo in the oviduct is managed by ciliary beating and muscular contractions. Because nonneuronally produced acetylcholine influences ciliary beating in the trachea via the muscarinic receptors M2 and M3, we supposed that components of the cholinergic system may also modulate ciliary activity in the oviduct. To address this issue, we analyzed the expression profile of muscarinic receptors (CHRMs) in the murine oviduct by RT-PCR and assessed ciliary beat frequency (CBF) and cilia-driven particle transport speed (PTS) on the mucosal surface of opened oviductal segments in correlation with histomorphological investigations. RT-PCR of laser-assisted microdissected epithelium revealed expression of Chrm subtypes Chrm1 and Chrm3. In opened isthmic segments, particle transport was barely seen, correlating with a significantly lower number of ciliated cells compared to the ampulla. In the ampulla, basal PTS and CBF were high (71 μm/sec and 21 Hz, respectively) both in cycling and pregnant wild-type mice and in mice with targeted deletion of the Chrm genes Chrm1, Chrm3, Chrm4, and Chrm5. In contrast to the trachea, where basal ciliary activity was low and largely enhanced by muscarinic stimulation, muscarinic agonists and antagonists did not affect the high ampullar PTS. Our results imply that this high oviductal autonomous ciliary activity is independent from the intrinsic cholinergic system and serves to maintain optimal clearance of the tube throughout all stages of the estrous cycle and early pregnancy.
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Affiliation(s)
- Katharina Noreikat
- Institute of Veterinary Anatomy, Histology, and Embryology, Justus-Liebig University, Giessen, Germany
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Konno A, Setou M, Ikegami K. Ciliary and flagellar structure and function--their regulations by posttranslational modifications of axonemal tubulin. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 294:133-70. [PMID: 22364873 DOI: 10.1016/b978-0-12-394305-7.00003-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Eukaryotic cilia and flagella are evolutionarily conserved microtubule-based organelles protruding from the cell surface. They perform dynein-driven beating which contributes to cell locomotion or flow generation. They also play important roles in sensing as cellular antennae, which allows cells to respond to various external stimuli. The main components of cilia and flagella, α- and β-tubulins, are known to undergo various posttranslational modifications (PTMs), including phosphorylation, palmitoylation, tyrosination/detyrosination, Δ2 modification, acetylation, glutamylation, and glycylation. Recent identification of tubulin-modifying enzymes, especially tubulin tyrosine ligase-like proteins which perform tubulin glutamylation and glycylation, has demonstrated the importance of tubulin modifications for the assembly and functions of cilia and flagella. In this chapter, we review recent work on PTMs of ciliary and flagellar tubulins in conjunction with discussing the basic knowledge.
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Affiliation(s)
- Alu Konno
- Department of Cell Biology and Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Hussong J, Schorr N, Belardi J, Prucker O, Rühe J, Westerweel J. Experimental investigation of the flow induced by artificial cilia. LAB ON A CHIP 2011; 11:2017-22. [PMID: 21614349 DOI: 10.1039/c0lc00722f] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The fluid transport produced by rectangular shaped, magnetically actuated artificial cilia of 70 μm length and 20 μm width was determined by means of phase-locked Micro Particle Image Velocimetry (μPIV) measurements in a closed microfluidic chamber. The phase-averaged flow produced by the artificial cilia reached up to 130 μm s(-1) with an actuation cycle frequency of 10 Hz. Analysis of the measured flow data indicate that the present system is capable of achieving volume flow rates of V[combining dot above](cilia) = 14 ± 4 μl min(-1) in a micro channel of 0.5 × 5 mm(2) cross-sectional area when no back pressure is built up. This corresponds to an effective pressure gradient of 6 ± 1 Pa m(-1), which equals a pressure difference of 0.6 ± 0.1 mPa over a distance of 100 μm between two rows of cilia. These results were derived analytically from the measured velocity profile by treating the cilia as a thin boundary layer. While the cilia produce phase-averaged velocities of the order of O(10(2)μm s(-1)), time-resolved measurements showed that the flow field reverses two times during one actuation cycle inducing instantaneous velocities of up to approximately 2 mm s(-1). This shows that the flow field is dominated by fluid oscillations and flow rates are expected to increase if the beating motion of the cilia is further improved.
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Affiliation(s)
- J Hussong
- Laboratory for Aero and Hydrodynamics, Delft University of Technology, Leeghwaterstraat 21, 2628 CA Delft, The Netherlands.
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Sommer JU, Gross S, Hörmann K, Stuck BA. Time-dependent changes in nasal ciliary beat frequency. Eur Arch Otorhinolaryngol 2010; 267:1383-7. [PMID: 20169353 DOI: 10.1007/s00405-010-1211-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 01/29/2010] [Indexed: 11/27/2022]
Abstract
As the ex vivo lifetime of nasal ciliary cells is limited, these cells have to be transferred to a culture medium for analysis with vital cytology immediately. Although the ciliary beat frequency (CBF) is likely to change over time, sufficient data regarding changes in the ex vivo CBF has not been published to date. In the present study, nasal epithelial cells were harvested from the mucosa of the inferior turbinate of 19 healthy volunteers with a cytology brush. Beating cilia were visualized with phase-contrast microscopy. Over a 12-h timeframe, 2 s epochs of video were captured every 5 min from the identical group of cells using a high-speed digital camera with a sampling rate of 100 fps. Temperature was maintained at about 22 degrees C and controlled by an infrared pyrometer. The CBF rapidly increased by 47 +/- 53% during the first 3 h of measurement. A relative plateau followed this increase from 3 to 9 h. After 9 h, CBF reduced linearly. After 12 h, the mean frequency reduced to 20 +/- 69% of baseline. However, there was considerable variance between the samples. The initial increase in CBF has not been reported previously. This interval seems to be unsuitable for meaningful measurements. Measurements of CBF are most reliable during the plateau phase between 3 and 9 h. After 9 h, there is clearly a significant decrease in CBF, together with a considerable interindividual variance.
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Affiliation(s)
- J Ulrich Sommer
- Department of Otorhinolaryngology Head and Neck Surgery, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
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Ghosh R, Buxton GA, Usta OB, Balazs AC, Alexeev A. Designing oscillating cilia that capture or release microscopic particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:2963-8. [PMID: 19799457 DOI: 10.1021/la902926w] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We use computational modeling to capture the three-dimensional interactions between oscillating, synthetic cilia and a microscopic particle in a fluid-filled microchannel. The synthetic cilia are elastic filaments that are tethered to a substrate and are actuated by a sinusoidal force, which is applied to their free ends. The cilia are arranged in a square pattern, and a neutrally buoyant particle is initially located between these filaments. Our computational studies reveal that, depending on frequency of the beating cilia, the particle can be either driven downward toward the substrate or driven upward and expelled into the fluid above the cilial layer. This behavior mimics the performance of biological cilia used by certain marine animals to extract suspended food particles. The findings uncover a new route for controlling the deposition of microscopic particles in microfluidic devices.
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Affiliation(s)
- Rajat Ghosh
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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