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Burkert N, Roy S, Häusler M, Wuttke D, Müller S, Wiemer J, Hollmann H, Oldrati M, Ramirez-Franco J, Benkert J, Fauler M, Duda J, Goaillard JM, Pötschke C, Münchmeyer M, Parlato R, Liss B. Deep learning-based image analysis identifies a DAT-negative subpopulation of dopaminergic neurons in the lateral Substantia nigra. Commun Biol 2023; 6:1146. [PMID: 37950046 PMCID: PMC10638391 DOI: 10.1038/s42003-023-05441-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 10/10/2023] [Indexed: 11/12/2023] Open
Abstract
Here we present a deep learning-based image analysis platform (DLAP), tailored to autonomously quantify cell numbers, and fluorescence signals within cellular compartments, derived from RNAscope or immunohistochemistry. We utilised DLAP to analyse subtypes of tyrosine hydroxylase (TH)-positive dopaminergic midbrain neurons in mouse and human brain-sections. These neurons modulate complex behaviour, and are differentially affected in Parkinson's and other diseases. DLAP allows the analysis of large cell numbers, and facilitates the identification of small cellular subpopulations. Using DLAP, we identified a small subpopulation of TH-positive neurons (~5%), mainly located in the very lateral Substantia nigra (SN), that was immunofluorescence-negative for the plasmalemmal dopamine transporter (DAT), with ~40% smaller cell bodies. These neurons were negative for aldehyde dehydrogenase 1A1, with a lower co-expression rate for dopamine-D2-autoreceptors, but a ~7-fold higher likelihood of calbindin-d28k co-expression (~70%). These results have important implications, as DAT is crucial for dopamine signalling, and is commonly used as a marker for dopaminergic SN neurons.
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Affiliation(s)
- Nicole Burkert
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Shoumik Roy
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany.
| | - Max Häusler
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | | | - Sonja Müller
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Johanna Wiemer
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Helene Hollmann
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Marvin Oldrati
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Jorge Ramirez-Franco
- UMR_S 1072, Aix Marseille Université, INSERM, Faculté de Médecine Secteur Nord, Marseille, France
- INT, Aix Marseille Université, CNRS, Campus Santé Timone, Marseille, France
| | - Julia Benkert
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Johanna Duda
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Jean-Marc Goaillard
- UMR_S 1072, Aix Marseille Université, INSERM, Faculté de Médecine Secteur Nord, Marseille, France
- INT, Aix Marseille Université, CNRS, Campus Santé Timone, Marseille, France
| | - Christina Pötschke
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
| | - Moritz Münchmeyer
- Wolution GmbH & Co. KG, 82152, Munich, Germany
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Rosanna Parlato
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany
- Division of Neurodegenerative Disorders, Department of Neurology, Medical Faculty Mannheim, Mannheim Center for Translational Neurosciences, Heidelberg University, 68167, Mannheim, Germany
| | - Birgit Liss
- Institute of Applied Physiology, Medical Faculty, Ulm University, 89081, Ulm, Germany.
- Linacre College & New College, Oxford University, OX1 2JD, Oxford, UK.
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2
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Hoang ON, Ermund A, Jaramillo AM, Fakih D, French CB, Flores JR, Karmouty-Quintana H, Magnusson JM, Fois G, Fauler M, Frick M, Braubach P, Hales JB, Kurten RC, Panettieri R, Vergara L, Ehre C, Adachi R, Tuvim MJ, Hansson GC, Dickey BF. Mucins MUC5AC and MUC5B Are Variably Packaged in the Same and in Separate Secretory Granules. Am J Respir Crit Care Med 2022; 206:1081-1095. [PMID: 35776514 PMCID: PMC9704839 DOI: 10.1164/rccm.202202-0309oc] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 07/01/2022] [Indexed: 01/27/2023] Open
Abstract
Rationale: MUC5AC (mucin 5AC, oligomeric gel-forming) and MUC5B (mucin 5B, oligomeric gel-forming) are the predominant secreted polymeric mucins in mammalian airways. They contribute differently to the pathogenesis of various muco-obstructive and interstitial lung diseases, and their genes are separately regulated, but whether they are packaged together or in separate secretory granules is not known. Objectives: To determine the packaging of MUC5AC and MUC5B within individual secretory granules in mouse and human airways under varying conditions of inflammation and along the proximal-distal axis. Methods: Lung tissue was obtained from mice stimulated to upregulate mucin production by the cytokines IL-1β and IL-13 or by porcine pancreatic elastase. Human lung tissue was obtained from donated normal lungs, biopsy samples of transplanted lungs, and explanted lungs from subjects with chronic obstructive pulmonary disease. MUC5AC and MUC5B were labeled with antibodies from different animal species or, in mice only, by transgenic chimeric mucin-fluorescent proteins and imaged using widefield deconvolution or Airyscan fluorescence microscopy. Measurements and Main Results: In both mouse and human airways, most secretory granules contained both mucins interdigitating within the granules. Smaller numbers of granules contained MUC5B alone, and even fewer contained MUC5AC alone. Conclusions: MUC5AC and MUC5B are variably stored both in the same and in separate secretory granules of both mice and humans. The high fraction of granules containing both mucins under a variety of conditions makes it unlikely that their secretion can be differentially controlled as a therapeutic strategy. This work also advances knowledge of the packaging of mucins within secretory granules to understand mechanisms of epithelial stress in the pathogenesis of chronic lung diseases.
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Affiliation(s)
- Oanh N. Hoang
- Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Anna Ermund
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Ana M. Jaramillo
- Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Dalia Fakih
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Cory B. French
- Washington University School of Medicine, St. Louis, Missouri
| | - Jose R. Flores
- Washington University School of Medicine, St. Louis, Missouri
| | - Harry Karmouty-Quintana
- Division of Critical Care, Pulmonary, and Sleep Medicine, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas
| | - Jesper M. Magnusson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Giorgio Fois
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
| | | | - Joshua B. Hales
- Washington University School of Medicine, St. Louis, Missouri
| | | | | | - Leoncio Vergara
- Institute of Biosciences and Technology, Texas A&M School of Medicine, Houston, Texas; and
| | - Camille Ehre
- Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Roberto Adachi
- Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Michael J. Tuvim
- Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Gunnar C. Hansson
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Burton F. Dickey
- Department of Pulmonary Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
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3
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Föhr KJ, Rapp M, Fauler M, Zimmer T, Jungwirth B, Messerer DAC. Block of Voltage-Gated Sodium Channels by Aripiprazole in a State-Dependent Manner. Int J Mol Sci 2022; 23:ijms232112890. [PMID: 36361681 PMCID: PMC9656591 DOI: 10.3390/ijms232112890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/05/2022] [Accepted: 10/20/2022] [Indexed: 11/24/2022] Open
Abstract
Aripiprazole is an atypical antipsychotic drug, which is prescribed for many psychiatric diseases such as schizophrenia and mania in bipolar disorder. It primarily acts as an agonist of dopaminergic and other G-protein coupled receptors. So far, an interaction with ligand- or voltage-gated ion channels has been classified as weak. Meanwhile, we identified aripiprazole in a preliminary test as a potent blocker of voltage-gated sodium channels. Here, we present a detailed analysis about the interaction of aripiprazole with the dominant voltage-gated sodium channel of heart muscle (hNav1.5). Electrophysiological experiments were performed by means of the patch clamp technique at human heart muscle sodium channels (hNav1.5), heterologously expressed in human TsA cells. Aripiprazole inhibits the hNav1.5 channel in a state- but not use-dependent manner. The affinity for the resting state is weak with an extrapolated Kr of about 55 µM. By contrast, the interaction with the inactivated state is strong. The affinities for the fast and slow inactivated state are in the low micromolar range (0.5–1 µM). Kinetic studies indicate that block development for the inactivated state must be described with a fast (ms) and a slow (s) time constant. Even though the time constants differ by a factor of about 50, the resulting affinity constants were nearly identical (in the range of 0.5 µM). Besides this, aripirazole also interacts with the open state of the channel. Using an inactivation deficit mutant, an affinity of about 1 µM was estimated. In summary, aripiprazole inhibits voltage-gated sodium channels at low micromolar concentrations. This property might add to its possible anticancer and neuroprotective properties.
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Affiliation(s)
- Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
- Correspondence:
| | - Michael Rapp
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, University of Ulm, 89081 Ulm, Germany
| | - Thomas Zimmer
- Institute of Physiology, University Hospital of Jena, 07747 Jena, Germany
| | - Bettina Jungwirth
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - David Alexander Christian Messerer
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
- Department of Transfusion Medicine and Hemostaseology, Friedrich-Alexander University Erlangen-Nuremberg, University Hospital Erlangen, 91052 Erlangen, Germany
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4
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Eisele J, Schreiner S, Borho J, Fischer S, Heber S, Endres S, Fellermann M, Wohlgemuth L, Huber-Lang M, Fois G, Fauler M, Frick M, Barth H. The Pore-Forming Subunit C2IIa of the Binary Clostridium botulinum C2 Toxin Reduces the Chemotactic Translocation of Human Polymorphonuclear Leukocytes. Front Pharmacol 2022; 13:810611. [PMID: 35222028 PMCID: PMC8881014 DOI: 10.3389/fphar.2022.810611] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 01/24/2022] [Indexed: 11/30/2022] Open
Abstract
The binary C2 toxin of Clostridium (C.) botulinum consists of two non-linked proteins, the enzyme subunit C2I and the separate binding/transport subunit C2II. To exhibit toxic effects on mammalian cells, proteolytically activated C2II (C2IIa) forms barrel-shaped heptamers that bind to carbohydrate receptors which are present on all mammalian cell types. C2I binds to C2IIa and the toxin complexes are internalized via receptor-mediated endocytosis. In acidified endosomal vesicles, C2IIa heptamers change their conformation and insert as pores into endosomal membranes. These pores serve as translocation-channels for the subsequent transport of C2I from the endosomal lumen into the cytosol. There, C2I mono-ADP-ribosylates G-actin, which results in depolymerization of F-actin and cell rounding. Noteworthy, so far morphological changes in cells were only observed after incubation with the complete C2 toxin, i.e., C2IIa plus C2I, but not with the single subunits. Unexpectedly, we observed that the non-catalytic transport subunit C2IIa (but not C2II) alone induced morphological changes and actin alterations in primary human polymorphonuclear leukocytes (PMNs, alias neutrophils) from healthy donors ex vivo, but not macrophages, epithelial and endothelial cells, as detected by phase contrast microscopy and fluorescent microscopy of the actin cytoskeleton. This suggests a PMN selective mode of action for C2IIa. The cytotoxicity of C2IIa on PMNs was prevented by C2IIa pore blockers and treatment with C2IIa (but not C2II) rapidly induced Ca2+ influx in PMNs, suggesting that pore-formation by C2IIa in cell membranes of PMNs is crucial for this effect. In addition, incubation of primary human PMNs with C2IIa decreased their chemotaxis ex vivo through porous culture inserts and in co-culture with human endothelial cells which is closer to the physiological extravasation process. In conclusion, the results suggest that C2IIa is a PMN-selective inhibitor of chemotaxis. This provides new knowledge for a pathophysiological role of C2 toxin as a modulator of innate immune cells and makes C2IIa an attractive candidate for the development of novel pharmacological strategies to selectively down-modulate the excessive and detrimental PMN recruitment into organs after traumatic injuries.
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Affiliation(s)
- Julia Eisele
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Simone Schreiner
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Joscha Borho
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Stephan Fischer
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Sebastian Heber
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Sascha Endres
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Maximilian Fellermann
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
| | - Lisa Wohlgemuth
- Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, Ulm University Medical Center, Ulm, Germany
| | - Giorgio Fois
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Holger Barth
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, Ulm, Germany
- *Correspondence: Holger Barth,
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5
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Fuchs E, Messerer DAC, Karpel-Massler G, Fauler M, Zimmer T, Jungwirth B, Föhr KJ. Block of Voltage-Gated Sodium Channels as a Potential Novel Anti-cancer Mechanism of TIC10. Front Pharmacol 2021; 12:737637. [PMID: 34744721 PMCID: PMC8567104 DOI: 10.3389/fphar.2021.737637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/15/2021] [Indexed: 12/19/2022] Open
Abstract
Background: Tumor therapeutics are aimed to affect tumor cells selectively while sparing healthy ones. For this purpose, a huge variety of different drugs are in use. Recently, also blockers of voltage-gated sodium channels (VGSCs) have been recognized to possess potentially beneficial effects in tumor therapy. As these channels are a frequent target of numerous drugs, we hypothesized that currently used tumor therapeutics might have the potential to block VGSCs in addition to their classical anti-cancer activity. In the present work, we have analyzed the imipridone TIC10, which belongs to a novel class of anti-cancer compounds, for its potency to interact with VGSCs. Methods: Electrophysiological experiments were performed by means of the patch-clamp technique using heterologously expressed human heart muscle sodium channels (hNav1.5), which are among the most common subtypes of VGSCs occurring in tumor cells. Results: TIC10 angular inhibited the hNav1.5 channel in a state- but not use-dependent manner. The affinity for the resting state was weak with an extrapolated Kr of about 600 μM. TIC10 most probably did not interact with fast inactivation. In protocols for slow inactivation, a half-maximal inhibition occurred around 2 µM. This observation was confirmed by kinetic studies indicating that the interaction occurred with a slow time constant. Furthermore, TIC10 also interacted with the open channel with an affinity of approximately 4 µM. The binding site for local anesthetics or a closely related site is suggested as a possible target as the affinity for the well-characterized F1760K mutant was reduced more than 20-fold compared to wild type. Among the analyzed derivatives, ONC212 was similarly effective as TIC10 angular, while TIC10 linear more selectively interacted with the different states. Conclusion: The inhibition of VGSCs at low micromolar concentrations might add to the anti-tumor properties of TIC10.
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Affiliation(s)
- Eva Fuchs
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| | | | | | - Michael Fauler
- Institute of General Physiology, University of Ulm, Ulm, Germany
| | - Thomas Zimmer
- Institute of Physiology, University Hospital of Jena, Jena, Germany
| | - Bettina Jungwirth
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| | - Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
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6
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Stratmann AEP, Wohlgemuth L, Erber ME, Bernhard S, Hug S, Fauler M, Vidoni L, Mohamed AOK, Thomaß BD, Münnich F, Stukan L, Föhr KJ, Mannes M, Huber-Lang MS, Messerer DAC. Simultaneous Measurement of Changes in Neutrophil Granulocyte Membrane Potential, Intracellular pH, and Cell Size by Multiparametric Flow Cytometry. Biomedicines 2021; 9:1504. [PMID: 34829733 PMCID: PMC8614908 DOI: 10.3390/biomedicines9111504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 01/10/2023] Open
Abstract
Neutrophils provide rapid and efficient defense mechanisms against invading pathogens. Upon stimulation with proinflammatory mediators, including complement factors and bacterial peptides, neutrophils respond with changes in their membrane potential, intracellular pH, and cellular size. This study provides an approach to quantify these important changes simultaneously using multiparametric flow cytometry, thereby revealing a typical sequence of neutrophil activation consisting of depolarization, alkalization, and increase in cellular size. Additionally, the time resolution of the flow cytometric measurement is improved in order to allow changes that occur within seconds to be monitored, and thus to enhance the kinetic analysis of the neutrophil response. The method is appropriate for the reliable semiquantitative detection of small variations with respect to an increase, no change, and decrease in those parameters as demonstrated by the screening of various proinflammatory mediators. As a translational outlook, the findings are put into context in inflammatory conditions in vitro as well as in a clinically relevant whole blood model of endotoxemia. Taken together, the multiparametric analysis of neutrophil responsiveness regarding depolarization, alkalization, and changes in cellular size may contribute to a better understanding of neutrophils in health and disease, thus potentially yielding innovative mechanistic insights and possible novel diagnostic and/or prognostic approaches.
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Affiliation(s)
| | - Lisa Wohlgemuth
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Maike Elisabeth Erber
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Stefan Bernhard
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Stefan Hug
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany
| | - Laura Vidoni
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Adam Omar Khalaf Mohamed
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Bertram Dietrich Thomaß
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Frederik Münnich
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Laura Stukan
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
| | - Marco Mannes
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Markus Stefan Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - David Alexander Christian Messerer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital Ulm, 89081 Ulm, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, 89081 Ulm, Germany
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7
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Lutz AK, Pfaender S, Incearap B, Ioannidis V, Ottonelli I, Föhr KJ, Cammerer J, Zoller M, Higelin J, Giona F, Stetter M, Stoecker N, Alami NO, Schön M, Orth M, Liebau S, Barbi G, Grabrucker AM, Delorme R, Fauler M, Mayer B, Jesse S, Roselli F, Ludolph AC, Bourgeron T, Verpelli C, Demestre M, Boeckers TM. Autism-associated SHANK3 mutations impair maturation of neuromuscular junctions and striated muscles. Sci Transl Med 2021; 12:12/547/eaaz3267. [PMID: 32522805 DOI: 10.1126/scitranslmed.aaz3267] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 12/09/2019] [Accepted: 04/07/2020] [Indexed: 12/12/2022]
Abstract
Heterozygous mutations of the gene encoding the postsynaptic protein SHANK3 are associated with syndromic forms of autism spectrum disorders (ASDs). One of the earliest clinical symptoms in SHANK3-associated ASD is neonatal skeletal muscle hypotonia. This symptom can be critical for the early diagnosis of affected children; however, the mechanism mediating hypotonia in ASD is not completely understood. Here, we used a combination of patient-derived human induced pluripotent stem cells (hiPSCs), Shank3Δ11(-/-) mice, and Phelan-McDermid syndrome (PMDS) muscle biopsies from patients of different ages to analyze the role of SHANK3 on motor unit development. Our results suggest that the hypotonia in SHANK3 deficiency might be caused by dysfunctions in all elements of the voluntary motor system: motoneurons, neuromuscular junctions (NMJs), and striated muscles. We found that SHANK3 localizes in Z-discs in the skeletal muscle sarcomere and co-immunoprecipitates with α-ACTININ. SHANK3 deficiency lead to shortened Z-discs and severe impairment of acetylcholine receptor clustering in hiPSC-derived myotubes and in muscle from Shank3Δ11(-/-) mice and patients with PMDS, indicating a crucial role for SHANK3 in the maturation of NMJs and striated muscle. Functional motor defects in Shank3Δ11(-/-) mice could be rescued with the troponin activator Tirasemtiv that sensitizes muscle fibers to calcium. Our observations give insight into the function of SHANK3 besides the central nervous system and imply potential treatment strategies for SHANK3-associated ASD.
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Affiliation(s)
- Anne-Kathrin Lutz
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Stefanie Pfaender
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Berra Incearap
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Valentin Ioannidis
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Ilaria Ottonelli
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Karl J Föhr
- Department of Anesthesiology, Ulm University Hospital, 89081 Ulm, Germany
| | - Judith Cammerer
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Marvin Zoller
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Julia Higelin
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Federica Giona
- CNR Neuroscience Institute, University of Milan, 20129 Milan, Italy.,BIOMETRA University of Milan, 20129 Milan, Italy
| | - Maximilian Stetter
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | - Nicole Stoecker
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | | | - Michael Schön
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany
| | | | - Stefan Liebau
- Institute of Neuroanatomy and Developmental Biology, Eberhard Karls University Tübingen, 72074 Tübingen, Germany
| | - Gotthold Barbi
- Institute for Human Genetics, Ulm University Hospital, 89081 Ulm, Germany
| | - Andreas M Grabrucker
- Cellular Neurobiology and Neuro-Nanotechnology Lab, Department of Biological Sciences, University of Limerick, V94PH61 Limerick, Ireland.,Bernal Institute, University of Limerick, V94T9PX Limerick, Ireland.,Health Research Institute (HRI), University of Limerick, V94T9PX Limerick, Ireland
| | - Richard Delorme
- Child and Adolescent Psychiatry Department, APHP, Robert-Debré Hospital, 750197 Paris, France
| | - Michael Fauler
- Institute of General Physiology, Ulm University, 89081 Ulm, Germany
| | - Benjamin Mayer
- Institute of Epidemiology and Medical Biometry, Ulm University, 89075 Ulm, Germany
| | | | | | | | - Thomas Bourgeron
- Génétique Humaine et Fonctions Cognitives, Université Paris Diderot, Institut Pasteur, 75015 Paris, France
| | - Chiara Verpelli
- CNR Neuroscience Institute, University of Milan, 20129 Milan, Italy.,BIOMETRA University of Milan, 20129 Milan, Italy
| | - Maria Demestre
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany.
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany. .,DZNE, Ulm Site, 89081 Ulm, Germany
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8
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Bernhard S, Hug S, Stratmann AEP, Erber M, Vidoni L, Knapp CL, Thomaß BD, Fauler M, Nilsson B, Nilsson Ekdahl K, Föhr K, Braun CK, Wohlgemuth L, Huber-Lang M, Messerer DAC. Interleukin 8 Elicits Rapid Physiological Changes in Neutrophils That Are Altered by Inflammatory Conditions. J Innate Immun 2021; 13:225-241. [PMID: 33857948 DOI: 10.1159/000514885] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 01/22/2021] [Indexed: 11/19/2022] Open
Abstract
A sufficient response of neutrophil granulocytes stimulated by interleukin (IL)-8 is vital during systemic inflammation, for example, in sepsis or severe trauma. Moreover, IL-8 is clinically used as biomarker of inflammatory processes. However, the effects of IL-8 on cellular key regulators of neutrophil properties such as the intracellular pH (pHi) in dependence of ion transport proteins and during inflammation remain to be elucidated. Therefore, we investigated in detail the fundamental changes in pHi, cellular shape, and chemotactic activity elicited by IL-8. Using flow cytometric methods, we determined that the IL-8-induced cellular activity was largely dependent on specific ion channels and transporters, such as the sodium-proton exchanger 1 (NHE1) and non-NHE1-dependent sodium flux. Exposing neutrophils in vitro to a proinflammatory micromilieu with N-formyl-Met-Leu-Phe, LPS, or IL-8 resulted in a diminished response regarding the increase in cellular size and pH. The detailed kinetics of the reduced reactivity of the neutrophil granulocytes could be illustrated in a near-real-time flow cytometric measurement. Last, the LPS-mediated impairment of the IL-8-induced response in neutrophils was confirmed in a translational, animal-free human whole blood model. Overall, we provide novel mechanistic insights for the interaction of IL-8 with neutrophil granulocytes and report in detail about its alteration during systemic inflammation.
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Affiliation(s)
- Stefan Bernhard
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Stefan Hug
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | | | - Maike Erber
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Laura Vidoni
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Christiane Leonie Knapp
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Bertram Dietrich Thomaß
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, University of Ulm, Ulm, Germany
| | - Bo Nilsson
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Kristina Nilsson Ekdahl
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Centre of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Karl Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| | - Christian Karl Braun
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany.,Department of Pediatrics and Adolescent Medicine, University Hospital of Ulm, Ulm, Germany
| | - Lisa Wohlgemuth
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - David Alexander Christian Messerer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany.,Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
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9
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Hug S, Bernhard S, Stratmann AEP, Erber M, Wohlgemuth L, Knapp CL, Bauer JM, Vidoni L, Fauler M, Föhr KJ, Radermacher P, Hoffmann A, Huber-Lang M, Messerer DAC. Activation of Neutrophil Granulocytes by Platelet-Activating Factor Is Impaired During Experimental Sepsis. Front Immunol 2021; 12:642867. [PMID: 33796110 PMCID: PMC8007865 DOI: 10.3389/fimmu.2021.642867] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
Platelet-activating factor (PAF) is an important mediator of the systemic inflammatory response. In the case of sepsis, proper activation and function of neutrophils as the first line of cellular defense are based on a well-balanced physiological response. However, little is known about the role of PAF in cellular changes of neutrophils during sepsis. Therefore, this study investigates the reaction patterns of neutrophils induced by PAF with a focus on membrane potential (MP), intracellular pH, and cellular swelling under physiological and pathophysiological conditions and hypothesizes that the PAF-mediated response of granulocytes is altered during sepsis. The cellular response of granulocytes including MP, intracellular pH, cellular swelling, and other activation markers were analyzed by multiparametric flow cytometry. In addition, the chemotactic activity and the formation of platelet-neutrophil complexes after exposure to PAF were investigated. The changes of the (electro-)physiological response features were translationally verified in a human ex vivo whole blood model of endotoxemia as well as during polymicrobial porcine sepsis. In neutrophils from healthy human donors, PAF elicited a rapid depolarization, an intracellular alkalization, and an increase in cell size in a time- and dose-dependent manner. Mechanistically, the alkalization was dependent on sodium-proton exchanger 1 (NHE1) activity, while the change in cellular shape was sodium flux- but only partially NHE1-dependent. In a pathophysiological altered environment, the PAF-induced response of neutrophils was modulated. Acidifying the extracellular pH in vitro enhanced PAF-mediated depolarization, whereas the increases in cell size and intracellular pH were largely unaffected. Ex vivo exposure of human whole blood to lipopolysaccharide diminished the PAF-induced intracellular alkalization and the change in neutrophil size. During experimental porcine sepsis, depolarization of the MP was significantly impaired. Additionally, there was a trend for increased cellular swelling, whereas intracellular alkalization remained stable. Overall, an impaired (electro-)physiological response of neutrophils to PAF stimulation represents a cellular hallmark of those cells challenged during systemic inflammation. Furthermore, this altered response may be indicative of and causative for the development of neutrophil dysfunction during sepsis.
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Affiliation(s)
- Stefan Hug
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Stefan Bernhard
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | | | - Maike Erber
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Lisa Wohlgemuth
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Christiane Leonie Knapp
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Jonas Martin Bauer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Laura Vidoni
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, University of Ulm, Ulm, Germany
| | - Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany
| | - Peter Radermacher
- Institute of Anesthesiological Pathophysiology and Process Development, University Hospital of Ulm, Ulm, Germany
| | - Andrea Hoffmann
- Institute of Anesthesiological Pathophysiology and Process Development, University Hospital of Ulm, Ulm, Germany
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany
| | - David Alexander Christian Messerer
- Institute of Clinical and Experimental Trauma Immunology, University Hospital of Ulm, Ulm, Germany.,Department of Anesthesiology and Intensive Care Medicine, University Hospital of Ulm, Ulm, Germany.,Institute of Anesthesiological Pathophysiology and Process Development, University Hospital of Ulm, Ulm, Germany
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10
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Mannal N, Kleiner K, Fauler M, Dougalis A, Poetschke C, Liss B. Multi-Electrode Array Analysis Identifies Complex Dopamine Responses and Glucose Sensing Properties of Substantia Nigra Neurons in Mouse Brain Slices. Front Synaptic Neurosci 2021; 13:635050. [PMID: 33716704 PMCID: PMC7952765 DOI: 10.3389/fnsyn.2021.635050] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/08/2021] [Indexed: 12/16/2022] Open
Abstract
Dopaminergic (DA) midbrain neurons within the substantia nigra (SN) display an autonomous pacemaker activity that is crucial for dopamine release and voluntary movement control. Their progressive degeneration is a hallmark of Parkinson's disease. Their metabolically demanding activity-mode affects Ca2+ homeostasis, elevates metabolic stress, and renders SN DA neurons particularly vulnerable to degenerative stressors. Accordingly, their activity is regulated by complex mechanisms, notably by dopamine itself, via inhibitory D2-autoreceptors and the neuroprotective neuronal Ca2+ sensor NCS-1. Analyzing regulation of SN DA neuron activity-pattern is complicated by their high vulnerability. We studied this activity and its control by dopamine, NCS-1, and glucose with extracellular multi-electrode array (MEA) recordings from midbrain slices of juvenile and adult mice. Our tailored MEA- and spike sorting-protocols allowed high throughput and long recording times. According to individual dopamine-responses, we identified two distinct SN cell-types, in similar frequency: dopamine-inhibited and dopamine-excited neurons. Dopamine-excited neurons were either silent in the absence of dopamine, or they displayed pacemaker-activities, similar to that of dopamine-inhibited neurons. Inhibition of pacemaker-activity by dopamine is typical for SN DA neurons, and it can undergo prominent desensitization. We show for adult mice, that the number of SN DA neurons with desensitized dopamine-inhibition was increased (~60–100%) by a knockout of NCS-1, or by prevention of NCS-1 binding to D2-autoreceptors, while time-course and degrees of desensitization were not altered. The number of neurons with desensitized D2-responses was also higher (~65%) at high glucose-levels (25 mM), compared to lower glucose (2.5 mM), while again desensitization-kinetics were unaltered. However, spontaneous firing-rates were significantly higher at high glucose-levels (~20%). Moreover, transient glucose-deprivation (1 mM) induced a fast and fully-reversible pacemaker frequency reduction. To directly address and quantify glucose-sensing properties of SN DA neurons, we continuously monitored their electrical activity, while altering extracellular glucose concentrations stepwise from 0.5 mM up to 25 mM. SN DA neurons were excited by glucose, with EC50 values ranging from 0.35 to 2.3 mM. In conclusion, we identified a novel, common subtype of dopamine-excited SN neurons, and a complex, joint regulation of dopamine-inhibited neurons by dopamine and glucose, within the range of physiological brain glucose-levels.
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Affiliation(s)
- Nadja Mannal
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | - Michael Fauler
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | | | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.,Linacre and New College, University of Oxford, Oxford, United Kingdom
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11
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Föhr KJ, Nastos A, Fauler M, Zimmer T, Jungwirth B, Messerer DAC. Block of Voltage-Gated Sodium Channels by Atomoxetine in a State- and Use-dependent Manner. Front Pharmacol 2021; 12:622489. [PMID: 33732157 PMCID: PMC7959846 DOI: 10.3389/fphar.2021.622489] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/08/2021] [Indexed: 12/13/2022] Open
Abstract
Atomoxetine, a neuroactive drug, is approved for the treatment of attention-deficit/hyperactivity disorder (ADHD). It is primarily known as a high affinity blocker of the noradrenaline transporter, whereby its application leads to an increased level of the corresponding neurotransmitter in different brain regions. However, the concentrations used to obtain clinical effects are much higher than those which are required to block the transporter system. Thus, off-target effects are likely to occur. In this way, we previously identified atomoxetine as blocker of NMDA receptors. As many psychotropic drugs give rise to sudden death of cardiac origin, we now tested the hypothesis whether atomoxetine also interacts with voltage-gated sodium channels of heart muscle type in clinically relevant concentrations. Electrophysiological experiments were performed by means of the patch-clamp technique at human heart muscle sodium channels (hNav1.5) heterogeneously expressed in human embryonic kidney cells. Atomoxetine inhibited sodium channels in a state- and use-dependent manner. Atomoxetine had only a weak affinity for the resting state of the hNav1.5 (Kr: ∼ 120 µM). The efficacy of atomoxetine strongly increased with membrane depolarization, indicating that the inactivated state is an important target. A hallmark of this drug was its slow interaction. By use of different experimental settings, we concluded that the interaction occurs with the slow inactivated state as well as by slow kinetics with the fast-inactivated state. Half-maximal effective concentrations (2–3 µM) were well within the concentration range found in plasma of treated patients. Atomoxetine also interacted with the open channel. However, the interaction was not fast enough to accelerate the time constant of fast inactivation. Nevertheless, when using the inactivation-deficient hNav1.5_I408W_L409C_A410W mutant, we found that the persistent late current was blocked half maximal at about 3 µM atomoxetine. The interaction most probably occurred via the local anesthetic binding site. Atomoxetine inhibited sodium channels at a similar concentration as it is used for the treatment of ADHD. Due to its slow interaction and by inhibiting the late current, it potentially exerts antiarrhythmic properties.
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Affiliation(s)
- Karl Josef Föhr
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, Ulm, Germany
| | - Ariadni Nastos
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, Ulm, Germany
| | - Michael Fauler
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Thomas Zimmer
- Institute of Physiology, University Hospital Jena, Jena, Germany
| | - Bettina Jungwirth
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Ulm, Ulm, Germany
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12
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Messerer DAC, Fauler M, Horneffer A, Schneider A, Keis O, Mauder LM, Radermacher P. Do medical students recognise the deteriorating patient by analysing their vital signs? A monocentric observational study based on the National Early Warning Score 2. BMJ Open 2021; 11:e044354. [PMID: 33622952 PMCID: PMC7907869 DOI: 10.1136/bmjopen-2020-044354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE Assessment of the expertise of medical students in evaluating vital signs and their implications for the current risk of a patient, an appropriate monitoring frequency, and a proper clinical response. METHODS 251 second-year and 267 fifth-year medical students in a curriculum consisting of 6 years of medical school at Ulm University, Germany, were interviewed in a paper-based questionnaire. The students were asked to rate their proficiency in interpreting vital signs and to give pathological thresholds of vital signs. Based on the National Early Warning Score 2 (NEWS2), nine vital signs of fictional patients were created and students were asked to comment on their clinical risk, to set an appropriate monitoring frequency as well as a clinical response. RESULTS Interviewing medical students regarding each vital sign individually, the students indicated a pathological threshold in accordance with the NEWS2 for respiratory rate, temperature, and heart rate. By contrast, inappropriate pathological limits were given regarding oxygen saturation and systolic blood pressure. Translating the vital signs into nine fictional patients, fifth-year medical students overall chose an appropriate response in 78% (67%-78%, median±IQR). In detail, fifth-year students successfully identified patients at very high or low risk and allocated them accordingly. However, cases on the edge were often stratified inappropriately. For example, a fictional case with vital signs indicating a surging sepsis was frequently underappreciated (48.5%) and allocated to an insufficient clinical response by fifth-year students. CONCLUSIONS Recognising the healthy as well as the deteriorating patient is a key ability for future physicians. NEWS2-based education might be a valuable tool to assess and give feedback on student's knowledge in this vital professional activity.
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Affiliation(s)
- David Alexander Christian Messerer
- Institute of Anaesthesiologic Pathophysiology and Method Development, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Astrid Horneffer
- Medical Faculty, Office of the Dean of Studies, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Achim Schneider
- Medical Faculty, Office of the Dean of Studies, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Oliver Keis
- Medical Faculty, Office of the Dean of Studies, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Lea-Marie Mauder
- Medical Faculty, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Peter Radermacher
- Institute of Anaesthesiologic Pathophysiology and Method Development, University Hospital Ulm, Ulm, Baden-Württemberg, Germany
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13
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Chakraborty S, Winkelmann VE, Braumüller S, Palmer A, Schultze A, Klohs B, Ignatius A, Vater A, Fauler M, Frick M, Huber-Lang M. Role of the C5a-C5a receptor axis in the inflammatory responses of the lungs after experimental polytrauma and hemorrhagic shock. Sci Rep 2021; 11:2158. [PMID: 33495506 PMCID: PMC7835219 DOI: 10.1038/s41598-020-79607-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 12/09/2020] [Indexed: 12/11/2022] Open
Abstract
Singular blockade of C5a in experimental models of sepsis is known to confer protection by rescuing lethality and decreasing pro-inflammatory responses. However, the role of inhibiting C5a has not been evaluated in the context of sterile systemic inflammatory responses, like polytrauma and hemorrhagic shock (PT + HS). In our presented study, a novel and highly specific C5a L-aptamer, NoxD21, was used to block C5a activity in an experimental murine model of PT + HS. The aim of the study was to assess early modulation of inflammatory responses and lung damage 4 h after PT + HS induction. NoxD21-treated PT + HS mice displayed greater polymorphonuclear cell recruitment in the lung, increased pro-inflammatory cytokine levels in the bronchoalveolar lavage fluids (BALF) and reduced myeloperoxidase levels within the lung tissue. An in vitro model of the alveolar-capillary barrier was established to confirm these in vivo observations. Treatment with a polytrauma cocktail induced barrier damage only after 16 h, and NoxD21 treatment in vitro did not rescue this effect. Furthermore, to test the exact role of both the cognate receptors of C5a (C5aR1 and C5aR2), experimental PT + HS was induced in C5aR1 knockout (C5aR1 KO) and C5aR2 KO mice. Following 4 h of PT + HS, C5aR2 KO mice had significantly reduced IL-6 and IL-17 levels in the BALF without significant lung damage, and both, C5aR1 KO and C5aR2 KO PT + HS animals displayed reduced MPO levels within the lungs. In conclusion, the C5aR2 could be a putative driver of early local inflammatory responses in the lung after PT + HS.
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Affiliation(s)
- Shinjini Chakraborty
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University Medical Center, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Veronika Eva Winkelmann
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Sonja Braumüller
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University Medical Center, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Annette Palmer
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University Medical Center, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Anke Schultze
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University Medical Center, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Bettina Klohs
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University Medical Center, Helmholtzstrasse 8/1, 89081, Ulm, Germany
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, Ulm University Medical Center, Helmholtzstrasse 14, 89081, Ulm, Germany
| | - Axel Vater
- Aptarion Biotech AG, Max-Dohrn-Str. 8-10, 10589, Berlin, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, Ulm University Medical Center, Helmholtzstrasse 8/1, 89081, Ulm, Germany.
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14
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Diem K, Fauler M, Fois G, Hellmann A, Winokurow N, Schumacher S, Kranz C, Frick M. Mechanical stretch activates piezo1 in caveolae of alveolar type I cells to trigger ATP release and paracrine stimulation of surfactant secretion from alveolar type II cells. FASEB J 2020; 34:12785-12804. [PMID: 32744386 DOI: 10.1096/fj.202000613rrr] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022]
Abstract
Secretion of pulmonary surfactant in the alveoli of the lungs is essential to maintain lung function. Stretching of alveoli during lung inflation is the main trigger for surfactant secretion. Yet, the molecular mechanisms how mechanical distension of alveoli results in surfactant secretion are still elusive. The alveolar epithelium consists of alveolar epithelial type I (ATI) and surfactant secreting type II (ATII) cells. ATI, but not ATII cells, express caveolae, small plasma membrane invaginations that can respond to plasma membrane stresses and serve mechanotransductive roles. Within this study, we investigated the role of caveolae as mechanosensors in the alveolus. We generated a human caveolin-1 knockout ATI cell (hAELVicav-/- ) using CRISPR/Cas9. Wildtype (hAELViwt ) and hAELVicav-/- cells grown on flexible membranes responded to increasing stretch amplitudes with rises in intracellular Ca2+ . The response was less frequent and started at higher stretch amplitudes in hAELVicav-/- cells. Stretch-induced Ca2+ -signals depended on Ca2+ -entry via piezo1 channels, localized within caveolae in hAELViwt and primary ATI cells. Ca2+ -entry via piezo1 activated pannexin-1 hemichannels resulting in ATP release from ATI cells. ATP release was reduced in hAELVicav-/- cells. In co-cultures resembling the alveolar epithelium, released ATP stimulated Ca2+ signals and surfactant secretion from neighboring ATII cells when co-cultured with hAELViwt but not hAELVicav-/- cells. In summary, we propose that caveolae in ATI cells are mechanosensors within alveoli regulating stretch-induced surfactant secretion from ATII cells.
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Affiliation(s)
- Kathrin Diem
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Giorgio Fois
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Andreas Hellmann
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Natalie Winokurow
- Institute of Molecular and Cellular Anatomy, Ulm University, Ulm, Germany
| | - Stefan Schumacher
- Institute of Molecular and Cellular Anatomy, Ulm University, Ulm, Germany
| | - Christine Kranz
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
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15
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Wirsching E, Fauler M, Fois G, Frick M. P2 Purinergic Signaling in the Distal Lung in Health and Disease. Int J Mol Sci 2020; 21:E4973. [PMID: 32674494 PMCID: PMC7404078 DOI: 10.3390/ijms21144973] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/07/2020] [Accepted: 07/10/2020] [Indexed: 12/13/2022] Open
Abstract
The distal lung provides an intricate structure for gas exchange in mammalian lungs. Efficient gas exchange depends on the functional integrity of lung alveoli. The cells in the alveolar tissue serve various functions to maintain alveolar structure, integrity and homeostasis. Alveolar epithelial cells secrete pulmonary surfactant, regulate the alveolar surface liquid (ASL) volume and, together with resident and infiltrating immune cells, provide a powerful host-defense system against a multitude of particles, microbes and toxicants. It is well established that all of these cells express purinergic P2 receptors and that purinergic signaling plays important roles in maintaining alveolar homeostasis. Therefore, it is not surprising that purinergic signaling also contributes to development and progression of severe pathological conditions like pulmonary inflammation, acute lung injury/acute respiratory distress syndrome (ALI/ARDS) and pulmonary fibrosis. Within this review we focus on the role of P2 purinergic signaling in the distal lung in health and disease. We recapitulate the expression of P2 receptors within the cells in the alveoli, the possible sources of ATP (adenosine triphosphate) within alveoli and the contribution of purinergic signaling to regulation of surfactant secretion, ASL volume and composition, as well as immune homeostasis. Finally, we summarize current knowledge of the role for P2 signaling in infectious pneumonia, ALI/ARDS and idiopathic pulmonary fibrosis (IPF).
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Affiliation(s)
| | | | | | - Manfred Frick
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (E.W.); (M.F.); (G.F.)
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16
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Lutz A, Jung D, Diem K, Fauler M, Port F, Gottschalk K, Felder E. Acute effects of cell stretch on keratin filaments in A549 lung cells. FASEB J 2020; 34:11227-11242. [PMID: 32632966 DOI: 10.1096/fj.201903160rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 05/29/2020] [Accepted: 06/18/2020] [Indexed: 12/31/2022]
Abstract
Keratin filaments (KFs) comprise the intermediate filaments of epithelial cells and are well known for their cytoprotective properties and their mechanical resilience. Although, several studies have demonstrated KFs' remarkable tensile properties relatively little is known about acute implications of mechanical stretch on KFs in living cells. This includes structural effects on the KFs and their higher level assembly structures as well as posttranslational response mechanisms to possibly modify KF's properties. We subjected simple epithelial A549 lung cells to 30% unidirectional stretch and already after 10 seconds we observed morphological changes of the KF-network as well as structural effects on their desmosomal anchor sites-both apparently caused by the tensile strain. Interestingly, the effect on the desmosomes was attenuated after 30 seconds of cell stretch with a concomitant increase in phosphorylation of keratin8-S432, keratin18-S53, and keratin18-S34 without an apparent increase in keratin solubility. When mimicking the phosphorylation of keratin18-S34 the stretch-induced effect on the desmosomes could be diminished and probing the cell surface with atomic force microscopy showed a lowered elastic modulus. We conclude that the stretch-induced KF phosphorylation affects KF's tensile properties, probably to lower the mechanical load on strained desmosomal cell-cell contacts, and hence, preserve epithelial integrity.
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Affiliation(s)
- Anngrit Lutz
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Dominik Jung
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Kathrin Diem
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Michael Fauler
- Department of General Physiology, Ulm University, Ulm, Germany
| | - Fabian Port
- Department of Experimental Physics, Ulm University, Ulm, Germany
| | - Kay Gottschalk
- Department of Experimental Physics, Ulm University, Ulm, Germany
| | - Edward Felder
- Department of General Physiology, Ulm University, Ulm, Germany
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Heck AJ, Ostertag T, Schnell L, Fischer S, Agrawalla BK, Winterwerber P, Wirsching E, Fauler M, Frick M, Kuan SL, Weil T, Barth H. Targeted Protein Delivery: Supramolecular Toxin Complexes for Targeted Pharmacological Modulation of Polymorphonuclear Leukocyte Functions (Adv. Healthcare Mater. 17/2019). Adv Healthc Mater 2019. [DOI: 10.1002/adhm.201970072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Astrid Johanna Heck
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Theresa Ostertag
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Leonie Schnell
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Stephan Fischer
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | | | - Pia Winterwerber
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Eva Wirsching
- Institute of General Physiology – Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Michael Fauler
- Institute of General Physiology – Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Manfred Frick
- Institute of General Physiology – Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Seah Ling Kuan
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
- Institute of Inorganic Chemistry IUlm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Tanja Weil
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
- Institute of Inorganic Chemistry IUlm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Holger Barth
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
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Heck AJ, Ostertag T, Schnell L, Fischer S, Agrawalla BK, Winterwerber P, Wirsching E, Fauler M, Frick M, Kuan SL, Weil T, Barth H. Supramolecular Toxin Complexes for Targeted Pharmacological Modulation of Polymorphonuclear Leukocyte Functions. Adv Healthc Mater 2019; 8:e1900665. [PMID: 31318180 DOI: 10.1002/adhm.201900665] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/04/2019] [Indexed: 12/19/2022]
Abstract
The targeted pharmacological modulation of polymorphonuclear leukocytes (PMNs) is of major medical interest. These innate immune cells play a central role in the defense against pathogenic microorganisms. However, their excessive chemotactic recruitment into tissues after traumatic injury is detrimental due to local and systemic inflammation. Rho-GTPases, being the master regulators of the actin cytoskeleton, regulate migration and chemotaxis of PMNs, are attractive pharmacological targets. Herein, supramolecular protein complexes are assembled in a "mix-and-match" approach containing the specific Rho-inhibiting clostridial C3 enzyme and three PMN-binding peptides using an avidin platform. Selective delivery of the C3 Rho-inhibitor with these complexes into the cytosol of human neutrophil-like NB-4 cells and primary human PMNs ex vivo is demonstrated, where they catalyze the adenosine diphosphate (ADP) ribosylation of Rho and induce a characteristic change in cell morphology. Notably, the complexes do not deliver C3 enzyme into human lung epithelial cells, A549 lung cancer cells, and immortalized human alveolar epithelial cells (hAELVi), demonstrating their cell type-selectivity. The supramolecular complexes represent attractive molecular tools to decipher the role of PMNs in infection and inflammation or for the development of novel therapeutic approaches for diseases that are associated with hyperactivity and reactivity of PMNs such as post-traumatic injury.
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Affiliation(s)
- Astrid Johanna Heck
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Theresa Ostertag
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Leonie Schnell
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Stephan Fischer
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | | | - Pia Winterwerber
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Eva Wirsching
- Institute of General Physiology – Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Michael Fauler
- Institute of General Physiology – Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Manfred Frick
- Institute of General Physiology – Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Seah Ling Kuan
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
- Institute of Inorganic Chemistry IUlm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Tanja Weil
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
- Institute of Inorganic Chemistry IUlm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
| | - Holger Barth
- Institute of Pharmacology and Toxicology – Ulm University Medical Center Albert‐Einstein‐Allee 11 89081 Ulm Germany
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Schnell L, Felix I, Müller B, Sadi M, Bank F, Papatheodorou P, Popoff MR, Aktories K, Waltenberger E, Benz R, Weichbrodt C, Fauler M, Frick M, Barth H. Revisiting an old antibiotic: bacitracin neutralizes binary bacterial toxins and protects cells from intoxication. FASEB J 2019; 33:5755-5771. [DOI: 10.1096/fj.201802453r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Leonie Schnell
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Ina Felix
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Bastian Müller
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Mirko Sadi
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | - Franziska Bank
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
| | | | | | - Klaus Aktories
- Institute of ExperimentalClinical Pharmacology and ToxicologyUniversity of Freiburg Freiburg Germany
| | - Eva Waltenberger
- Department of Life Sciences and ChemistryJacobs University Bremen Bremen Germany
| | - Roland Benz
- Department of Life Sciences and ChemistryJacobs University Bremen Bremen Germany
| | | | - Michael Fauler
- Institute of General PhysiologyUniversity of Ulm Ulm Germany
| | - Manfred Frick
- Institute of General PhysiologyUniversity of Ulm Ulm Germany
| | - Holger Barth
- Institute of Pharmacology and ToxicologyUniversity of Ulm Medical Center Ulm Germany
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Fois G, Föhr KJ, Kling C, Fauler M, Wittekindt OH, Dietl P, Frick M. P2X 4 receptor re-sensitization depends on a protonation/deprotonation cycle mediated by receptor internalization and recycling. J Physiol 2018; 596:4893-4907. [PMID: 30144063 DOI: 10.1113/jp275448] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 08/21/2018] [Indexed: 12/28/2022] Open
Abstract
KEY POINTS Re-sensitization of P2X4 receptors depends on a protonation/de-protonation cycle Protonation and de-protonation of the receptors is achieved by internalization and recycling of P2X4 receptors via acidic compartments Protonation and de-protonation occurs at critical histidine residues within the extracellular loop of P2X4 receptors Re-sensitization is blocked in the presence of the receptor agonist ATP ABSTRACT: P2X4 receptors are members of the P2X receptor family of cation-permeable, ligand-gated ion channels that open in response to the binding of extracellular ATP. P2X4 receptors are implicated in a variety of biological processes, including cardiac function, cell death, pain sensation and immune responses. These physiological functions depend on receptor activation on the cell surface. Receptor activation is followed by receptor desensitization and deactivation upon removal of ATP. Subsequent re-sensitization is required to return the receptor into its resting state. Desensitization and re-sensitization are therefore crucial determinants of P2X receptor signal transduction and responsiveness to ATP. However, the molecular mechanisms controlling desensitization and re-sensitization are not fully understood. In the present study, we provide evidence that internalization and recycling via acidic compartments is essential for P2X4 receptor re-sensitization. Re-sensitization depends on a protonation/de-protonation cycle of critical histidine residues within the extracellular loop of P2X4 receptors that is mediated by receptor internalization and recycling. Interestingly, re-sensitization under acidic conditions is completely revoked by receptor agonist ATP. Our data support the physiological importance of the unique subcellular distribution of P2X4 receptors that is predominantly found within acidic compartments. Based on these findings, we suggest that recycling of P2X4 receptors regulates the cellular responsiveness in the sustained presence of ATP.
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Affiliation(s)
| | - Karl J Föhr
- Department of Anesthesiology, University of Ulm, Ulm, Germany
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Richter J, Kretz AL, Lemke J, Fauler M, Werner JU, Paschke S, Leithäuser F, Henne-Bruns D, Hillenbrand A, Knippschild U. CK1α overexpression correlates with poor survival in colorectal cancer. BMC Cancer 2018; 18:140. [PMID: 29409464 PMCID: PMC5801892 DOI: 10.1186/s12885-018-4019-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/22/2018] [Indexed: 12/20/2022] Open
Abstract
Background Colorectal cancer (CRC) is the fourth leading cause of cancer related deaths worldwide and prognosis in advanced tumor stage still remains poor. Since CK1 isoforms have been reported to be deregulated in several tumor entities CK1 has emerged as a novel drug target in cancer therapy. In this study we set out to investigate whether CK1α might have the potential to serve as prognostic marker. Methods CK1α RNA and protein expression levels in healthy and tumor tissue of CRC patients were analyzed using quantitative real-time PCR and Western Blot analysis, respectively. Prognostic relevance was investigated by correlating obtained CK1α expression levels with patients’ survival rate generating Kaplan-Meier survival plots. Results It could be shown that CK1α is overexpressed in colorectal tumor tissue compared to normal tissue and CK1α overexpression in tumor tissue correlates with poor survival in CRC patients. Results become more significant when only considering patients with high-grade tumors, as well as patients assigned to UICC II and UICC III stage. Furthermore, Cox regression analysis revealed that CK1α is an independent prognostic factor. In addition, tumors expressing decreased levels of the kinase reveal positive effects on overall survival when localized in the right colon compared to those in the left side. Conclusion In summary, this study provides evidence for the first time that CK1α RNA levels might serve as prognostic marker for CRC. Electronic supplementary material The online version of this article (10.1186/s12885-018-4019-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Julia Richter
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Anna-Laura Kretz
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Johannes Lemke
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Michael Fauler
- Ulm University, Institute of General Physiology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Jens-Uwe Werner
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Stephan Paschke
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Frank Leithäuser
- Department of Pathology, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Doris Henne-Bruns
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Andreas Hillenbrand
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany
| | - Uwe Knippschild
- Department of General and Visceral Surgery, Ulm University Hospital, Albert-Einstein-Allee 23, 89081, Ulm, Germany.
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Schmidt H, Michel C, Braubach P, Fauler M, Neubauer D, Thompson KE, Frick M, Mizaikoff B, Dietl P, Wittekindt OH. Water Permeability Adjusts Resorption in Lung Epithelia to Increased Apical Surface Liquid Volumes. Am J Respir Cell Mol Biol 2017; 56:372-382. [DOI: 10.1165/rcmb.2016-0161oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Hanna Schmidt
- Institute of General Physiology, Ulm University, Ulm, Germany
| | | | - Peter Braubach
- Institute of Pathology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Daniel Neubauer
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany; and
| | - Kristin E. Thompson
- Institute of General Physiology, Ulm University, Ulm, Germany
- Institute de la Santé et de la Recherche Médicale, UMR_S938, Sorbonne Universités, Paris, France
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany; and
| | - Paul Dietl
- Institute of General Physiology, Ulm University, Ulm, Germany
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Föhr KJ, Knippschild U, Herkommer A, Fauler M, Peifer C, Georgieff M, Adolph O. State-dependent block of voltage-gated sodium channels by the casein-kinase 1 inhibitor IC261. Invest New Drugs 2017; 35:277-289. [PMID: 28164251 DOI: 10.1007/s10637-017-0429-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/12/2017] [Indexed: 12/13/2022]
Abstract
Background and Purpose IC261 (3-[(2,4,6-trimethoxyphenyl)methylidenyl]-indolin-2-one) has previously been introduced as an isoform specific inhibitor of casein kinase 1 (CK1) causing cell cycle arrest or cell death of established tumor cell lines. However, it is reasonable to assume that not all antitumor activities of IC261 are mediated by the inhibition of CK1. Meanwhile there is growing evidence that functional voltage-gated sodium channels are also implicated in the progression of tumors as their blockage suppresses tumor migration and invasion of different tumor cell lines. Thus, we asked whether IC261 functionally inhibits voltage-gated sodium channels. Experimental Approach Electrophysiological experiments were performed using the patch-clamp technique at human heart muscle sodium channels heterologously expressed in human TsA cells. Key Results IC261 inhibits sodium channels in a state-dependent manner. IC261 does not interact with the open channel and has only a low affinity for the resting state of the hNav1.5 (human voltage-gated sodium channel; Kr: 120 μM). The efficacy of IC261 strongly increases with membrane depolarisation, indicating that the inactivated state is an important target. The results of different experimental approaches finally revealed an affinity of IC261 to the inactivated state between 1 and 2 μM. Conclusion and Implications IC261 inhibits sodium channels at a similar concentration necessary to reduce CK1δ/ε activity by 50% (IC50 value 1 μM). Thus, inhibition of sodium channels might contribute to the antitumor activity of IC261.
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Affiliation(s)
- Karl J Föhr
- Department of Anesthesiology, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89075, Ulm, Germany.
| | - Uwe Knippschild
- Department of General and Visceral Surgery, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89081, Ulm, Germany
| | - Anna Herkommer
- Department of Anesthesiology, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89081, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, University of Ulm, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
| | - Christian Peifer
- Institute of Pharmacy, University of Kiel, Gutenbergstr. 76, D-24118, Kiel, Germany
| | - Michael Georgieff
- Department of Anesthesiology, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89075, Ulm, Germany
| | - Oliver Adolph
- Department of Anesthesiology, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89075, Ulm, Germany
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Tavakoli S, Rappl S, Fauler M, Frick M, Gottschalk K, Hobi N. Mechanobiophysics of the alveolus – Reconstruction of strain and forces at the gas-blood barrier. Pneumologie 2016. [DOI: 10.1055/s-0036-1583498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Eschbach J, von Einem B, Müller K, Bayer H, Scheffold A, Morrison BE, Rudolph KL, Thal DR, Witting A, Weydt P, Otto M, Fauler M, Liss B, McLean PJ, Spada ARL, Ludolph AC, Weishaupt JH, Danzer KM. Mutual exacerbation of peroxisome proliferator-activated receptor γ coactivator 1α deregulation and α-synuclein oligomerization. Ann Neurol 2014; 77:15-32. [PMID: 25363075 DOI: 10.1002/ana.24294] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 09/29/2014] [Accepted: 10/05/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Aggregation of α-synuclein (α-syn) and α-syn cytotoxicity are hallmarks of sporadic and familial Parkinson disease (PD), with accumulating evidence that prefibrillar oligomers and protofibrils are the pathogenic species in PD and related synucleinopathies. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a key regulator of mitochondrial biogenesis and cellular energy metabolism, has recently been associated with the pathophysiology of PD. Despite extensive effort on studying the function of PGC-1α in mitochondria, no studies have addressed whether PGC-1α directly influences oligomerization of α-syn or whether α-syn oligomers impact PGC-1α expression. MATERIALS AND METHODS We tested whether pharmacological or genetic activation of PGC-1α or PGC-11α knockdown could modulate the oligomerization of α-syn in vitro by using an α-syn -fragment complementation assay. RESULTS In this study, we found that both PGC-1α reference gene (RG-PGC-1α) and the central nervous system (CNS)-specific PGC-1α (CNS-PGC-1α) are downregulated in human PD brain, in A30P α-syn transgenic animals, and in a cell culture model for α-syn oligomerization. Importantly, downregulation of both RG-PGC-1α and CNS-PGC-1α in cell culture or neurons from RG-PGC-1α-deficient mice leads to a strong induction of α-syn oligomerization and toxicity. In contrast, pharmacological activation or genetic overexpression of RG-PGC-1α reduced α-syn oligomerization and rescued α-syn-mediated toxicity. INTERPRETATION Based on our results, we propose that PGC-1α downregulation and α-syn oligomerization form a vicious circle, thereby influencing and/or potentiating each other. Our data indicate that restoration of PGC-1α is a promising approach for development of effective drugs for the treatment of PD and related synucleinopathies.
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Affiliation(s)
- Judith Eschbach
- Department of Neurology, Ulm University, Ulm, Germany; Inoviem Scientific, Strasbourg, France
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Dragicevic E, Poetschke C, Duda J, Schlaudraff F, Lammel S, Schiemann J, Fauler M, Hetzel A, Watanabe M, Lujan R, Malenka RC, Striessnig J, Liss B. Cav1.3 channels control D2-autoreceptor responses via NCS-1 in substantia nigra dopamine neurons. ACTA ACUST UNITED AC 2014; 137:2287-302. [PMID: 24934288 PMCID: PMC4107734 DOI: 10.1093/brain/awu131] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Dopamine midbrain neurons within the substantia nigra are particularly prone to degeneration in Parkinson's disease. Their selective loss causes the major motor symptoms of Parkinson's disease, but the causes for the high vulnerability of SN DA neurons, compared to neighbouring, more resistant ventral tegmental area dopamine neurons, are still unclear. Consequently, there is still no cure available for Parkinson's disease. Current therapies compensate the progressive loss of dopamine by administering its precursor l-DOPA and/or dopamine D2-receptor agonists. D2-autoreceptors and Cav1.3-containing L-type Ca(2+) channels both contribute to Parkinson's disease pathology. L-type Ca(2+) channel blockers protect SN DA neurons from degeneration in Parkinson's disease and its mouse models, and they are in clinical trials for neuroprotective Parkinson's disease therapy. However, their physiological functions in SN DA neurons remain unclear. D2-autoreceptors tune firing rates and dopamine release of SN DA neurons in a negative feedback loop through activation of G-protein coupled potassium channels (GIRK2, or KCNJ6). Mature SN DA neurons display prominent, non-desensitizing somatodendritic D2-autoreceptor responses that show pronounced desensitization in PARK-gene Parkinson's disease mouse models. We analysed surviving human SN DA neurons from patients with Parkinson's disease and from controls, and detected elevated messenger RNA levels of D2-autoreceptors and GIRK2 in Parkinson's disease. By electrophysiological analysis of postnatal juvenile and adult mouse SN DA neurons in in vitro brain-slices, we observed that D2-autoreceptor desensitization is reduced with postnatal maturation. Furthermore, a transient high-dopamine state in vivo, caused by one injection of either l-DOPA or cocaine, induced adult-like, non-desensitizing D2-autoreceptor responses, selectively in juvenile SN DA neurons, but not ventral tegmental area dopamine neurons. With pharmacological and genetic tools, we identified that the expression of this sensitized D2-autoreceptor phenotype required Cav1.3 L-type Ca(2+) channel activity, internal Ca(2+), and the interaction of the neuronal calcium sensor NCS-1 with D2-autoreceptors. Thus, we identified a first physiological function of Cav1.3 L-type Ca(2+) channels in SN DA neurons for homeostatic modulation of their D2-autoreceptor responses. L-type Ca(2+) channel activity however, was not important for pacemaker activity of mouse SN DA neurons. Furthermore, we detected elevated substantia nigra dopamine messenger RNA levels of NCS-1 (but not Cav1.2 or Cav1.3) after cocaine in mice, as well as in remaining human SN DA neurons in Parkinson's disease. Thus, our findings provide a novel homeostatic functional link in SN DA neurons between Cav1.3- L-type-Ca(2+) channels and D2-autoreceptor activity, controlled by NCS-1, and indicate that this adaptive signalling network (Cav1.3/NCS-1/D2/GIRK2) is also active in human SN DA neurons, and contributes to Parkinson's disease pathology. As it is accessible to pharmacological modulation, it provides a novel promising target for tuning substantia nigra dopamine neuron activity, and their vulnerability to degeneration.
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Affiliation(s)
- Elena Dragicevic
- 1 Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | - Johanna Duda
- 1 Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Falk Schlaudraff
- 1 Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Stephan Lammel
- 2 Nancy Pritzker Laboratory, Department of Psychiatry and Behavioural Sciences, Stanford University School of Medicine, Palo Alto, USA
| | - Julia Schiemann
- 3 Institute of Neurophysiology, Goethe University Frankfurt, Germany
| | - Michael Fauler
- 1 Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Andrea Hetzel
- 4 Rosalind Franklin University of Medicine and Science, North Chicago, USA
| | - Masahiko Watanabe
- 5 Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan
| | - Rafael Lujan
- 6 Instituto de Investigación en Discapacidades Neurológicas (IDINE), Departamento de Ciencias Médicas, Universidad Castilla-La Mancha, Albacete, Spain
| | - Robert C Malenka
- 2 Nancy Pritzker Laboratory, Department of Psychiatry and Behavioural Sciences, Stanford University School of Medicine, Palo Alto, USA
| | - Joerg Striessnig
- 7 Institute of Pharmacy, Department of Pharmacology and Toxicology, Centre of Molecular Biosciences, University of Innsbruck, Austria
| | - Birgit Liss
- 1 Institute of Applied Physiology, University of Ulm, Ulm, Germany
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Schlaudraff F, Gründemann J, Fauler M, Dragicevic E, Hardy J, Liss B. Orchestrated increase of dopamine and PARK mRNAs but not miR-133b in dopamine neurons in Parkinson's disease. Neurobiol Aging 2014; 35:2302-15. [PMID: 24742361 PMCID: PMC4099518 DOI: 10.1016/j.neurobiolaging.2014.03.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 02/27/2014] [Accepted: 03/14/2014] [Indexed: 01/25/2023]
Abstract
Progressive loss of substantia nigra dopamine neurons (SN DA) is a hallmark of aging and of Parkinson's disease (PD). Mutations in PARK genes cause familial PD forms. Increased expression of alpha-synuclein (PARK4) is a disease-triggering event in familial PD and also observed in SN DA neurons in sporadic PD but related transcriptional changes are unknown. With optimized single-cell quantitative real-time polymerase chain reaction analysis, we compared messenger RNA and microRNA levels in SN DA neurons from sporadic PD patients and controls. Non-optimally matched donor ages and RNA integrities are common problems when analyzing human samples. We dissected the influence of distinct ages and RNA integrities of our samples by applying a specifically-optimized, linear-mixed-effects model to quantitative real-time polymerase chain reaction-data. We identified that elevated alpha-synuclein messenger RNA levels in SN DA neurons of human PD brains were positively correlated with corresponding elevated levels of mRNAs for functional compensation of progressive SN DA loss and for enhanced proteasomal (PARK5/UCHL1) and lysosomal (PARK9/ATPase13A2) function, possibly counteracting alpha-synuclein toxicity. In contrast, microRNA miR-133b levels, previously implicated in transcriptional dysregulation in PD, were not altered in SN DA neurons in PD.
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Affiliation(s)
- Falk Schlaudraff
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Jan Gründemann
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Michael Fauler
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Elena Dragicevic
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - John Hardy
- Department of Molecular Neuroscience and Reta Lila Weston Laboratories, Institute of Neurology, London, UK
| | - Birgit Liss
- Department of Applied Physiology, Institute of Applied Physiology, University of Ulm, Ulm, Germany.
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Felder E, Fauler M, Geiler S. Introducing e-learning/teaching in a physiology course for medical students: acceptance by students and subjective effect on learning. Adv Physiol Educ 2013; 37:337-342. [PMID: 24292910 DOI: 10.1152/advan.00158.2012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Retrieval of information has substantially changed within the last two decades. Naturally, this has also affected learning/teaching techniques, and methods that are commonly referred to as "e-learning" have become an important part in modern education. Institutions have to decide if (and how) to implement this new form of teaching but face the problem that little subject-specific research has been published for different teaching modes and methods. The present study compares a course module of the physiology laboratory course for medical students in the preclinical phase before and after the introduction of computer-aided course instructions (CACI). Students were provided with an online questionnaire containing Likert items evaluating workspace redesign, acceptance of course instructions, incentive to actively participate in the course, and subjective gain of knowledge. CACI was clearly preferred over the previously used paper workbook. However, the questionnaire also revealed that the gain in knowledge, as subjectively perceived by the students, had not improved, which is in agreement with several studies that neglected a beneficial effect of e-learning on learning success. We conclude that the CACI meet today's student's expectations and that introducing this system seems justified from this perspective.
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Affiliation(s)
- E Felder
- Institute for General Physiology, University of Ulm, Ulm, Germany
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Seebohm G, Strutz-Seebohm N, Ursu ON, Preisig-Müller R, Zuzarte M, Hill EV, Kienitz MC, Bendahhou S, Fauler M, Tapken D, Decher N, Collins A, Jurkat-Rott K, Steinmeyer K, Lehmann-Horn F, Daut J, Tavaré JM, Pott L, Bloch W, Lang F. Altered stress stimulation of inward rectifier potassium channels in Andersen-Tawil syndrome. FASEB J 2011; 26:513-22. [PMID: 22002906 DOI: 10.1096/fj.11-189126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Inward rectifier potassium channels of the Kir2 subfamily are important determinants of the electrical activity of brain and muscle cells. Genetic mutations in Kir2.1 associate with Andersen-Tawil syndrome (ATS), a familial disorder leading to stress-triggered periodic paralysis and ventricular arrhythmia. To identify the molecular mechanisms of this stress trigger, we analyze Kir channel function and localization electrophysiologically and by time-resolved confocal microscopy. Furthermore, we employ a mathematical model of muscular membrane potential. We identify a novel corticoid signaling pathway that, when activated by glucocorticoids, leads to enrichment of Kir2 channels in the plasma membranes of mammalian cell lines and isolated cardiac and skeletal muscle cells. We further demonstrate that activation of this pathway can either partly restore (40% of cases) or further impair (20% of cases) the function of mutant ATS channels, depending on the particular Kir2.1 mutation. This means that glucocorticoid treatment might either alleviate or deteriorate symptoms of ATS depending on the patient's individual Kir2.1 genotype. Thus, our findings provide a possible explanation for the contradictory effects of glucocorticoid treatment on symptoms in patients with ATS and may open new pathways for the design of personalized medicines in ATS therapy.
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Affiliation(s)
- Guiscard Seebohm
- Department of Biochemistry I-Cation Channel Group, Ruhr University Bochum, Bochum, Germany.
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Fauler M, Jurkat-Rott K, Lehmann-Horn F. Facets of acute myogenic tetraparesis. KLIN NEUROPHYSIOL 2010. [DOI: 10.1055/s-0030-1251014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Fauler M, Jurkat-Rott K, Lehmann-Horn F. Activation of the Na+/K+/2 Cl−-Cotransporter in Mammalian Skeletal Muscle. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.3615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Weber YG, Storch A, Wuttke TV, Brockmann K, Kempfle J, Maljevic S, Margari L, Kamm C, Schneider SA, Huber SM, Pekrun A, Roebling R, Seebohm G, Koka S, Lang C, Kraft E, Blazevic D, Salvo-Vargas A, Fauler M, Mottaghy FM, Münchau A, Edwards MJ, Presicci A, Margari F, Gasser T, Lang F, Bhatia KP, Lehmann-Horn F, Lerche H. GLUT1 mutations are a cause of paroxysmal exertion-induced dyskinesias and induce hemolytic anemia by a cation leak. J Clin Invest 2008; 118:2157-68. [PMID: 18451999 DOI: 10.1172/jci34438] [Citation(s) in RCA: 277] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 03/19/2008] [Indexed: 11/17/2022] Open
Abstract
Paroxysmal dyskinesias are episodic movement disorders that can be inherited or are sporadic in nature. The pathophysiology underlying these disorders remains largely unknown but may involve disrupted ion homeostasis due to defects in cell-surface channels or nutrient transporters. In this study, we describe a family with paroxysmal exertion-induced dyskinesia (PED) over 3 generations. Their PED was accompanied by epilepsy, mild developmental delay, reduced CSF glucose levels, hemolytic anemia with echinocytosis, and altered erythrocyte ion concentrations. Using a candidate gene approach, we identified a causative deletion of 4 highly conserved amino acids (Q282_S285del) in the pore region of the glucose transporter 1 (GLUT1). Functional studies in Xenopus oocytes and human erythrocytes revealed that this mutation decreased glucose transport and caused a cation leak that alters intracellular concentrations of sodium, potassium, and calcium. We screened 4 additional families, in which PED is combined with epilepsy, developmental delay, or migraine, but not with hemolysis or echinocytosis, and identified 2 additional GLUT1 mutations (A275T, G314S) that decreased glucose transport but did not affect cation permeability. Combining these data with brain imaging studies, we propose that the dyskinesias result from an exertion-induced energy deficit that may cause episodic dysfunction of the basal ganglia, and that the hemolysis with echinocytosis may result from alterations in intracellular electrolytes caused by a cation leak through mutant GLUT1.
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Affiliation(s)
- Yvonne G Weber
- Neurologische Klinik and Institut für Anatomie und Zellbiologie, Universität Ulm, Ulm, Germany
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33
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Wuttke TV, Penzien J, Fauler M, Seebohm G, Lehmann-Horn F, Lerche H, Jurkat-Rott K. Neutralization of a negative charge in the S1-S2 region of the KV7.2 (KCNQ2) channel affects voltage-dependent activation in neonatal epilepsy. J Physiol 2007; 586:545-55. [PMID: 18006581 DOI: 10.1113/jphysiol.2007.143826] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The voltage-gated potassium channels KV7.2 and KV7.3 (genes KCNQ2 and KCNQ3) constitute a major component of the M-current controlling the firing rate in many neurons. Mutations within these two channel subunits cause benign familial neonatal convulsions (BFNC). Here we identified a novel BFNC-causing mutation (E119G) in the S1-S2 region of KV7.2. Electrophysiological investigations in Xenopus oocytes using two-microelectrode voltage clamping revealed that the steady-state activation curves for E119G alone and its coexpressions with KV7.2 and/or KV7.3 wild-type (WT) channels were significantly shifted in the depolarizing direction compared to KV7.2 or KV7.2/KV7.3. These shifts reduced the relative current amplitudes for mutant channels particularly in the subthreshold range of an action potential (about 45% reduction at --50 mV for E119G compared to KV7.2, and 33% for E119G/KV7.3 compared to KV7.2/KV7.3 channels). Activation kinetics were significantly slowed for mutant channels. Our results indicate that small changes in channel gating at subthreshold voltages are sufficient to cause neonatal seizures and demonstrate the importance of the M-current for this voltage range. This was confirmed by a computer model predicting an increased burst duration for the mutation. On a molecular level, these results reveal a critical role in voltage sensing of the negatively charged E119 in S1-S2 of KV7.2, a region that-- according to molecular modelling - might interact with a positive charge in the S4 segment.
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Weber YG, Storch A, Wuttke TV, Brockmann K, Kempfle J, Blacevic D, Pekrun A, Fauler M, Lehmann-Horn F, Lerche H. Leaky glucose transporters cause paroxysmal exertion-induced dyskinesia with haemolytic anaemia and epilepsy. Akt Neurol 2007. [DOI: 10.1055/s-2007-987579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Jurkat-Rott K, Fauler M, Lehmann-Horn F. Ion channels and ion transporters of the transverse tubular system of skeletal muscle. J Muscle Res Cell Motil 2006; 27:275-90. [PMID: 16933023 DOI: 10.1007/s10974-006-9088-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 07/05/2006] [Indexed: 11/27/2022]
Abstract
This review focuses on the electrical properties of the transverse (T) tubular membrane of skeletal muscle, with reference to the contribution of the T-tubular system (TTS) to the surface action potential, the radial spread of excitation and its role in excitation-contraction coupling. Particularly, the most important ion channels and ion transporters that enable proper depolarization and repolarization of the T-tubular membrane are described. Since propagation of excitation along the TTS into the depth of the fibers is a delicate balance between excitatory and inhibitory currents, the composition of channels and transporters is specific to the TTS and different from the surface membrane. The TTS normally enables the radial spread of excitation and the signal transfer to the sarcoplasmic reticulum to release calcium that activates the contractile apparatus. However, due to its structure, even slight shifts of ions may alter its volume, Nernstian potentials, ion permeabilities, and consequently T-tubular membrane potential and excitability.
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