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Barendrecht S, Schreurs A, Geissler S, Sabanov V, Ilse V, Rieckmann V, Eichentopf R, Künemund A, Hietel B, Wussow S, Hoffmann K, Körber-Ferl K, Pandey R, Carter GW, Demuth HU, Holzer M, Roßner S, Schilling S, Preuss C, Balschun D, Cynis H. A novel human tau knock-in mouse model reveals interaction of Abeta and human tau under progressing cerebral amyloidosis in 5xFAD mice. Alzheimers Res Ther 2023; 15:16. [PMID: 36641439 PMCID: PMC9840277 DOI: 10.1186/s13195-022-01144-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [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: 02/11/2022] [Accepted: 12/14/2022] [Indexed: 01/16/2023]
Abstract
BACKGROUND Hyperphosphorylation and intraneuronal aggregation of the microtubule-associated protein tau is a major pathological hallmark of Alzheimer's disease (AD) brain. Of special interest is the effect of cerebral amyloid beta deposition, the second main hallmark of AD, on human tau pathology. Therefore, studying the influence of cerebral amyloidosis on human tau in a novel human tau knock-in (htau-KI) mouse model could help to reveal new details on their interplay. METHODS We studied the effects of a novel human htau-KI under fast-progressing amyloidosis in 5xFAD mice in terms of correlation of gene expression data with human brain regions, development of Alzheimer's-like pathology, synaptic transmission, and behavior. RESULTS The main findings are an interaction of human beta-amyloid and human tau in crossbred 5xFADxhtau-KI observed at transcriptional level and corroborated by electrophysiology and histopathology. The comparison of gene expression data of the 5xFADxhtau-KI mouse model to 5xFAD, control mice and to human AD patients revealed conspicuous changes in pathways related to mitochondria biology, extracellular matrix, and immune function. These changes were accompanied by plaque-associated MC1-positive pathological tau that required the htau-KI background. LTP deficits were noted in 5xFAD and htau-KI mice in contrast to signs of rescue in 5xFADxhtau-KI mice. Increased frequencies of miniature EPSCs and miniature IPSCs indicated an upregulated presynaptic function in 5xFADxhtau-KI. CONCLUSION In summary, the multiple interactions observed between knocked-in human tau and the 5xFAD-driven progressing amyloidosis have important implications for future model development in AD.
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Affiliation(s)
- Susan Barendrecht
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - An Schreurs
- grid.5596.f0000 0001 0668 7884KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Tiensestraat 102, box 3714, 3000 Leuven, Belgium
| | - Stefanie Geissler
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Victor Sabanov
- grid.5596.f0000 0001 0668 7884KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Tiensestraat 102, box 3714, 3000 Leuven, Belgium
| | - Victoria Ilse
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Vera Rieckmann
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Rico Eichentopf
- grid.5596.f0000 0001 0668 7884KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Tiensestraat 102, box 3714, 3000 Leuven, Belgium
| | - Anja Künemund
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Benjamin Hietel
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Sebastian Wussow
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Katrin Hoffmann
- grid.9018.00000 0001 0679 2801Martin Luther University Halle-Wittenberg, Institute for Human Genetics, Magdeburger Strasse 2, 06112 Halle, Germany
| | - Kerstin Körber-Ferl
- grid.9018.00000 0001 0679 2801Martin Luther University Halle-Wittenberg, Institute for Human Genetics, Magdeburger Strasse 2, 06112 Halle, Germany
| | - Ravi Pandey
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory, 600 Main St, Bar Harbor, ME 04609 USA
| | - Gregory W. Carter
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory, 600 Main St, Bar Harbor, ME 04609 USA
| | - Hans-Ulrich Demuth
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
| | - Max Holzer
- Paul Flechsig Institute for Brain Research, Leipzig University, Liebigstraße 19, 04103 Leipzig, Germany
| | - Steffen Roßner
- Paul Flechsig Institute for Brain Research, Leipzig University, Liebigstraße 19, 04103 Leipzig, Germany
| | - Stephan Schilling
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany ,grid.427932.90000 0001 0692 3664Anhalt University of Applied Sciences, Bernburger Straße 55, 06366 Köthen, Germany
| | - Christoph Preuss
- grid.249880.f0000 0004 0374 0039The Jackson Laboratory, 600 Main St, Bar Harbor, ME 04609 USA
| | - Detlef Balschun
- grid.5596.f0000 0001 0668 7884KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Tiensestraat 102, box 3714, 3000 Leuven, Belgium
| | - Holger Cynis
- grid.418008.50000 0004 0494 3022Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany
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Latif-Hernandez A, Sabanov V, Ahmed T, Craessaerts K, Saito T, Saido T, Balschun D. The two faces of synaptic failure in App NL-G-F knock-in mice. Alzheimers Res Ther 2020; 12:100. [PMID: 32838792 PMCID: PMC7445922 DOI: 10.1186/s13195-020-00667-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [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: 05/13/2020] [Accepted: 08/10/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Intensive basic and preclinical research into Alzheimer's disease (AD) has yielded important new findings, but they could not yet been translated into effective therapies. One of the reasons is the lack of animal models that sufficiently reproduce the complexity of human AD and the response of human brain circuits to novel treatment approaches. As a step in overcoming these limitations, new App knock-in models have been developed that avoid transgenic APP overexpression and its associated side effects. These mice are proposed to serve as valuable models to examine Aß-related pathology in "preclinical AD." METHODS Since AD as the most common form of dementia progresses into synaptic failure as a major cause of cognitive deficits, the detailed characterization of synaptic dysfunction in these new models is essential. Here, we addressed this by extracellular and whole-cell patch-clamp recordings in AppNL-G-F mice compared to AppNL animals which served as controls. RESULTS We found a beginning synaptic impairment (LTP deficit) at 3-4 months in the prefrontal cortex of AppNL-G-F mice that is further aggravated and extended to the hippocampus at 6-8 months. Measurements of miniature EPSCs and IPSCs point to a marked increase in excitatory and inhibitory presynaptic activity, the latter accompanied by a moderate increase in postsynaptic inhibitory function. CONCLUSIONS Our data reveal a marked impairment of primarily postsynaptic processes at the level of synaptic plasticity but the dominance of a presumably compensatory presynaptic upregulation at the level of elementary miniature synaptic function.
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Affiliation(s)
- Amira Latif-Hernandez
- Brain and Cognition, KU Leuven, Tiensestraat 102, Box 3714, 3000, Leuven, Belgium
- Present Address: Neurology and Neurological Sciences, Stanford Medicine, Stanford, USA
| | - Victor Sabanov
- Brain and Cognition, KU Leuven, Tiensestraat 102, Box 3714, 3000, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Tariq Ahmed
- Brain and Cognition, KU Leuven, Tiensestraat 102, Box 3714, 3000, Leuven, Belgium
- Present Address: Qatar Biomedical Research Institute, Ar-Rayyan, Qatar
| | - Katleen Craessaerts
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for the Biology of Disease, Leuven, Belgium
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako-shi, Saitama, Japan
- Present Address: Department of Neurocognitive Science, Nagoya City University Graduate School of Medical Science, Nagoya, Aichi, Japan
| | - Takaomi Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Center for Brain Science, Wako-shi, Saitama, Japan
| | - Detlef Balschun
- Brain and Cognition, KU Leuven, Tiensestraat 102, Box 3714, 3000, Leuven, Belgium.
- Leuven Brain Institute, KU Leuven, Leuven, Belgium.
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Koch N, Koch D, Krueger S, Tröger J, Sabanov V, Ahmed T, McMillan LE, Wolf D, Montag D, Kessels MM, Balschun D, Qualmann B. Syndapin I Loss-of-Function in Mice Leads to Schizophrenia-Like Symptoms. Cereb Cortex 2020; 30:4306-4324. [DOI: 10.1093/cercor/bhaa013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
Abstract
Schizophrenia is associated with cognitive and behavioral dysfunctions thought to reflect imbalances in neurotransmission systems. Recent screenings suggested that lack of (functional) syndapin I (PACSIN1) may be linked to schizophrenia. We therefore studied syndapin I KO mice to address the suggested causal relationship to schizophrenia and to analyze associated molecular, cellular, and neurophysiological defects. Syndapin I knockout (KO) mice developed schizophrenia-related behaviors, such as hyperactivity, reduced anxiety, reduced response to social novelty, and an exaggerated novel object response and exhibited defects in dendritic arborization in the cortex. Neuromorphogenic deficits were also observed for a schizophrenia-associated syndapin I mutant in cultured neurons and coincided with a lack of syndapin I–mediated membrane recruitment of cytoskeletal effectors. Syndapin I KO furthermore caused glutamatergic hypofunctions. Syndapin I regulated both AMPAR and NMDAR availabilities at synapses during basal synaptic activity and during synaptic plasticity—particularly striking were a complete lack of long-term potentiation and defects in long-term depression in syndapin I KO mice. These synaptic plasticity defects coincided with alterations of postsynaptic actin dynamics, synaptic GluA1 clustering, and GluA1 mobility. Both GluA1 and GluA2 were not appropriately internalized. Summarized, syndapin I KO led to schizophrenia-like behavior, and our analyses uncovered associated molecular and cellular mechanisms.
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Affiliation(s)
- Nicole Koch
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Dennis Koch
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Sarah Krueger
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Jessica Tröger
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Victor Sabanov
- Laboratory of Biological Psychology, Brain & Cognition, University of Leuven, 3000 Leuven, Belgium
| | - Tariq Ahmed
- Laboratory of Biological Psychology, Brain & Cognition, University of Leuven, 3000 Leuven, Belgium
| | - Laura E McMillan
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - David Wolf
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Dirk Montag
- Neurogenetics Lab, Leibniz Institute for Neurobiology, 39116 Magdeburg, Germany
| | - Michael M Kessels
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Detlef Balschun
- Laboratory of Biological Psychology, Brain & Cognition, University of Leuven, 3000 Leuven, Belgium
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
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Scheyltjens I, Vreysen S, Van den Haute C, Sabanov V, Balschun D, Baekelandt V, Arckens L. Transient and localized optogenetic activation of somatostatin-interneurons in mouse visual cortex abolishes long-term cortical plasticity due to vision loss. Brain Struct Funct 2018; 223:2073-2095. [PMID: 29372324 PMCID: PMC5968055 DOI: 10.1007/s00429-018-1611-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 05/17/2017] [Accepted: 01/14/2018] [Indexed: 04/13/2023]
Abstract
Unilateral vision loss through monocular enucleation (ME) results in partial reallocation of visual cortical territory to another sense in adult mice. The functional recovery of the visual cortex occurs through a combination of spared-eye potentiation and cross-modal reactivation driven by whisker-related, somatosensory inputs. Brain region-specific intracortical inhibition was recently recognized as a crucial regulator of the cross-modal component, yet the contribution of specific inhibitory neuron subpopulations remains poorly understood. Somatostatin (SST)-interneurons are ideally located within the cortical circuit to modulate sensory integration. Here we demonstrate that optogenetic stimulation of visual cortex SST-interneurons prior to eye removal decreases ME-induced cross-modal recovery at the stimulation site. Our results suggest that SST-interneurons act as local hubs, which are able to control the influx and extent of cortical cross-modal inputs into the deprived cortex. These insights critically expand our understanding of SST-interneuron-specific regulation of cortical plasticity induced by sensory loss.
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Affiliation(s)
- Isabelle Scheyltjens
- Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Naamsestraat 59, Box 2467, 3000, Leuven, Belgium.
| | - Samme Vreysen
- Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Naamsestraat 59, Box 2467, 3000, Leuven, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, KU Leuven, 3000, Leuven, Belgium.,Leuven Viral Vector Core, KU Leuven, 3000, Leuven, Belgium
| | - Victor Sabanov
- Laboratory of Biological Psychology, KU Leuven, 3000, Leuven, Belgium
| | - Detlef Balschun
- Laboratory of Biological Psychology, KU Leuven, 3000, Leuven, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, KU Leuven, 3000, Leuven, Belgium
| | - Lutgarde Arckens
- Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Naamsestraat 59, Box 2467, 3000, Leuven, Belgium
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Schreurs A, Sabanov V, Balschun D. Distinct Properties of Long-Term Potentiation in the Dentate Gyrus along the Dorsoventral Axis: Influence of Age and Inhibition. Sci Rep 2017; 7:5157. [PMID: 28698637 PMCID: PMC5506024 DOI: 10.1038/s41598-017-05358-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 05/26/2017] [Indexed: 02/07/2023] Open
Abstract
The hippocampus is important for spatial navigation, episodic memory and affective behaviour. Increasing evidence suggests that these multiple functions are accomplished by different segments along the dorsal-ventral (septal-temporal) axis. Long-term potentiation (LTP), the best-investigated cellular correlate of learning and memory, has distinct properties along this axis in the CA1 region, but so far, little is known about longitudinal differences in dentate gyrus (DG). Therefore, here we examined potential dorsoventral differences in DG-LTP using in vitro multi-electrode array recordings. In young mice, we found higher basal synaptic transmission in the dorsal DG, while the LTP magnitude markedly increased towards the ventral pole. Strikingly, these differences were greatly reduced in slices from middle-aged mice. Short-term plasticity, evaluated by paired-pulse ratios, was similar across groups. Recordings in the presence and absence of GABAA-receptor blocker picrotoxin suggested a higher inhibitory tone in the ventral DG of young mice, confirmed by an increased frequency of miniature inhibitory postsynaptic currents. Our findings support the view that the hippocampus contains discrete functional domains along its dorsoventral axis and demonstrate that these are subject to age-dependent changes. Since these characteristics are presumably conserved in the human hippocampus, our findings have important clinical implications for hippocampus- and age-related disorders.
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Affiliation(s)
- An Schreurs
- KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Laboratory of Biological Psychology, Leuven, Belgium
| | - Victor Sabanov
- KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Laboratory of Biological Psychology, Leuven, Belgium
| | - Detlef Balschun
- KU Leuven, Faculty of Psychology and Educational Sciences, Brain & Cognition, Laboratory of Biological Psychology, Leuven, Belgium.
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Bhattacharya S, Herrera-Molina R, Sabanov V, Ahmed T, Iscru E, Stöber F, Richter K, Fischer KD, Angenstein F, Goldschmidt J, Beesley PW, Balschun D, Smalla KH, Gundelfinger ED, Montag D. Genetically Induced Retrograde Amnesia of Associative Memories After Neuroplastin Ablation. Biol Psychiatry 2017; 81:124-135. [PMID: 27215477 DOI: 10.1016/j.biopsych.2016.03.2107] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 03/12/2016] [Accepted: 03/21/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUND Neuroplastin cell recognition molecules have been implicated in synaptic plasticity. Polymorphisms in the regulatory region of the human neuroplastin gene (NPTN) are correlated with cortical thickness and intellectual abilities in adolescents and in individuals with schizophrenia. METHODS We characterized behavioral and functional changes in inducible conditional neuroplastin-deficient mice. RESULTS We demonstrate that neuroplastins are required for associative learning in conditioning paradigms, e.g., two-way active avoidance and fear conditioning. Retrograde amnesia of learned associative memories is elicited by inducible neuron-specific ablation of Nptn gene expression in adult mice, which shows that neuroplastins are indispensable for the availability of previously acquired associative memories. Using single-photon emission computed tomography imaging in awake mice, we identified brain structures activated during memory recall. Constitutive neuroplastin deficiency or Nptn gene ablation in adult mice causes substantial electrophysiologic deficits such as reduced long-term potentiation. In addition, neuroplastin-deficient mice reveal profound physiologic and behavioral deficits, some of which are related to depression and schizophrenia, which illustrate neuroplastin's essential functions. CONCLUSIONS Neuroplastins are essential for learning and memory. Retrograde amnesia after an associative learning task can be induced by ablation of the neuroplastin gene. The inducible neuroplastin-deficient mouse model provides a new and unique means to analyze the molecular and cellular mechanisms underlying retrograde amnesia and memory.
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Affiliation(s)
- Soumee Bhattacharya
- Neurogenetics Special Laboratory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Rodrigo Herrera-Molina
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Special Laboratory Electron and Laserscanning Microscopy, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Victor Sabanov
- Laboratory of Biological Psychology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Tariq Ahmed
- Laboratory of Biological Psychology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Emilia Iscru
- Laboratory of Biological Psychology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Franziska Stöber
- Research Group Neuropharmacology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Karin Richter
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University, Magdeburg, Germany
| | - Klaus-Dieter Fischer
- Institute for Biochemistry and Cell Biology, Otto-von-Guericke University, Magdeburg, Germany
| | - Frank Angenstein
- Special Laboratory Noninvasive Brain Imaging, Leibniz Institute for Neurobiology, Magdeburg, Germany; Helmholtz Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioral Neurosciences and Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Jürgen Goldschmidt
- Department Systems Physiology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Philip W Beesley
- Special Laboratory for Molecular Biology Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany; School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, United Kingdom
| | | | - Karl-Heinz Smalla
- Special Laboratory for Molecular Biology Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Neurosciences and Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Eckart D Gundelfinger
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Helmholtz Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioral Neurosciences and Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Dirk Montag
- Neurogenetics Special Laboratory, Leibniz Institute for Neurobiology, Magdeburg, Germany.
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Schreurs A, Leenders N, Sabanov V, Van Den Haute C, Welkenhuysen M, Hoffman L, Braeken D, Baekelandt V, Balschun D. Optogenetic inhibition of long-term potentiation in the mouse dentate gyrus. Front Neurosci 2017. [DOI: 10.3389/conf.fnins.2017.94.00047] [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: 11/13/2022] Open
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Sabanov V, Braat S, D'Andrea L, Willemsen R, Zeidler S, Rooms L, Bagni C, Kooy RF, Balschun D. Impaired GABAergic inhibition in the hippocampus of Fmr1 knockout mice. Neuropharmacology 2016; 116:71-81. [PMID: 28012946 DOI: 10.1016/j.neuropharm.2016.12.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [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: 05/18/2016] [Revised: 11/30/2016] [Accepted: 12/12/2016] [Indexed: 01/24/2023]
Abstract
Many clinical and molecular features of the fragile X syndrome, a common form of intellectual disability and autism, can be modeled by deletion of the Fmr1 protein (Fmrp) in mice. Previous studies showed a decreased expression of several components of the GABAergic system in Fmr1 knockout mice. Here, we used this mouse model to investigate the functional consequences of Fmrp deletion on hippocampal GABAergic inhibition in the CA1-region of the hippocampus. Whole-cell patch-clamp recordings demonstrated a significantly reduced amplitude of evoked inhibitory postsynaptic currents (eIPSCs) and a decrease in the amplitude and frequency of spontaneous IPSCs. In addition, miniature IPSCs were reduced in amplitude and frequency and decayed significantly slower than mIPSCs in controls. Quantitative real-time PCR revealed a significantly lower expression of α2, β1 and δ GABAA receptor subunits in the hippocampus of the juvenile mice (P22) compared to wild-type littermates. Correspondingly, we found also at the protein level reduced amounts of α2, β1 and δ subunits in Fmr1 knockout mice. Overall, these results demonstrate that the reduction in several components of the GABAergic system is already present at young age and that this reduction results in measurable abnormalities on GABAA receptor-mediated phasic inhibition. These abnormalities might contribute to the behavioral and cognitive deficits of this fragile X mouse model.
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Affiliation(s)
- Victor Sabanov
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium.
| | - Sien Braat
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
| | - Laura D'Andrea
- Center for Human Genetics-VIB Center for the Biology of Disease, KULeuven, Leuven, Belgium; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy.
| | - Rob Willemsen
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
| | - Shimriet Zeidler
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands.
| | - Liesbeth Rooms
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium.
| | - Claudia Bagni
- Center for Human Genetics-VIB Center for the Biology of Disease, KULeuven, Leuven, Belgium; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy; Department of Fundamental Neuroscience, University of Lausanne, Switzerland.
| | - R Frank Kooy
- Department of Medical Genetics, University of Antwerp, Antwerp, Belgium.
| | - Detlef Balschun
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium.
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Fazzari P, Snellinx A, Sabanov V, Ahmed T, Serneels L, Gartner A, Shariati SAM, Balschun D, De Strooper B. Cell autonomous regulation of hippocampal circuitry via Aph1b-γ-secretase/neuregulin 1 signalling. eLife 2014; 3. [PMID: 24891237 PMCID: PMC4073283 DOI: 10.7554/elife.02196] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [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: 01/02/2014] [Accepted: 05/29/2014] [Indexed: 12/27/2022] Open
Abstract
Neuregulin 1 (NRG1) and the γ-secretase subunit APH1B have been previously implicated as genetic risk factors for schizophrenia and schizophrenia relevant deficits have been observed in rodent models with loss of function mutations in either gene. Here we show that the Aph1b-γ-secretase is selectively involved in Nrg1 intracellular signalling. We found that Aph1b-deficient mice display a decrease in excitatory synaptic markers. Electrophysiological recordings show that Aph1b is required for excitatory synaptic transmission and plasticity. Furthermore, gain and loss of function and genetic rescue experiments indicate that Nrg1 intracellular signalling promotes dendritic spine formation downstream of Aph1b-γ-secretase in vitro and in vivo. In conclusion, our study sheds light on the physiological role of Aph1b-γ-secretase in brain and provides a new mechanistic perspective on the relevance of NRG1 processing in schizophrenia. DOI:http://dx.doi.org/10.7554/eLife.02196.001 Schizophrenia affects around 1% of the world's population, with symptoms including hallucinations and delusions, apathy and cognitive impairments. Multiple genes and environmental factors interact to increase the risk of schizophrenia, making the causes of the disease—which can differ between individuals—difficult to disentangle. However, Schizophrenia is known to be associated with a reduction in the number of dendritic spines, the small protrusions that allow brain cells to receive inputs from other brain cells. One gene that has repeatedly been implicated in schizophrenia is neuregulin 1 (NRG1), which encodes a signalling protein with more than thirty different variants. One of these variants, type III NRG1, is located on the cell membrane. An enzyme called γ-secretase can cleave the 'tail' of this protein, which means that the tail becomes free to move to the nucleus of the cell, where it can alter the expression of genes. Fazzari et al. have now studied how different γ-secretases interact with type III NRG1 by using genetic techniques to remove a specific part of the enzymes in the brains of mice. The brain cells of these mutant mice contained fewer dendritic spines than mice with normal γ-secretases. However, the number of dendritic spines in the mutant mice could be restored by introducing γ-secretase. These results are consistent with a model in which mutations that remove the ability of γ-secretases to cleave NRG1 lead to some of the structural and functional changes in the brain that are associated with schizophrenia. An improved understanding of the properties of the various γ-secretases could also lead to the design of safer versions of drugs called γ-secretase modulators that are used to treat Alzheimer's disease. DOI:http://dx.doi.org/10.7554/eLife.02196.002
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Affiliation(s)
- Pietro Fazzari
- VIB Center for the Biology of Disease, KU Leuven, Leuven, Belgium
| | - An Snellinx
- VIB Center for the Biology of Disease, KU Leuven, Leuven, Belgium
| | - Victor Sabanov
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium
| | - Tariq Ahmed
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium
| | | | - Annette Gartner
- VIB Center for the Biology of Disease, KU Leuven, Leuven, Belgium
| | - S Ali M Shariati
- VIB Center for the Biology of Disease, KU Leuven, Leuven, Belgium
| | - Detlef Balschun
- Laboratory of Biological Psychology, KU Leuven, Leuven, Belgium
| | - Bart De Strooper
- VIB Center for the Biology of Disease, KU Leuven, Leuven, Belgium
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10
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Koch D, Spiwoks-Becker I, Sabanov V, Sinning A, Dugladze T, Stellmacher A, Ahuja R, Grimm J, Schüler S, Müller A, Angenstein F, Ahmed T, Diesler A, Moser M, Tom Dieck S, Spessert R, Boeckers TM, Fässler R, Hübner CA, Balschun D, Gloveli T, Kessels MM, Qualmann B. Proper synaptic vesicle formation and neuronal network activity critically rely on syndapin I. EMBO J 2011; 30:4955-69. [PMID: 21926968 DOI: 10.1038/emboj.2011.339] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 08/23/2011] [Indexed: 02/03/2023] Open
Abstract
Synaptic transmission relies on effective and accurate compensatory endocytosis. F-BAR proteins may serve as membrane curvature sensors and/or inducers and thereby support membrane remodelling processes; yet, their in vivo functions urgently await disclosure. We demonstrate that the F-BAR protein syndapin I is crucial for proper brain function. Syndapin I knockout (KO) mice suffer from seizures, a phenotype consistent with excessive hippocampal network activity. Loss of syndapin I causes defects in presynaptic membrane trafficking processes, which are especially evident under high-capacity retrieval conditions, accumulation of endocytic intermediates, loss of synaptic vesicle (SV) size control, impaired activity-dependent SV retrieval and defective synaptic activity. Detailed molecular analyses demonstrate that syndapin I plays an important role in the recruitment of all dynamin isoforms, central players in vesicle fission reactions, to the membrane. Consistently, syndapin I KO mice share phenotypes with dynamin I KO mice, whereas their seizure phenotype is very reminiscent of fitful mice expressing a mutant dynamin. Thus, syndapin I acts as pivotal membrane anchoring factor for dynamins during regeneration of SVs.
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Affiliation(s)
- Dennis Koch
- Institute of Biochemistry I, Jena University Hospital-Friedrich Schiller University Jena, Jena, Germany
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11
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Ahmed T, Sabanov V, D'Hooge R, Balschun D. An N-methyl-d-aspartate-receptor dependent, late-phase long-term depression in middle-aged mice identifies no GluN2-subunit bias. Neuroscience 2011; 185:27-38. [DOI: 10.1016/j.neuroscience.2011.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 03/17/2011] [Accepted: 04/03/2011] [Indexed: 10/18/2022]
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12
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Sabanov V, Nedergaard J. Ca(2+) -independent effects of BAPTA and EGTA on single-channel Cl(-) currents in brown adipocytes. Biochim Biophys Acta 2007; 1768:2714-25. [PMID: 17716619 DOI: 10.1016/j.bbamem.2007.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 06/29/2007] [Accepted: 07/02/2007] [Indexed: 10/23/2022]
Abstract
The Cl(-) channels of brown adipocytes electrophysiologically resemble outwardly rectifying Cl(-) channels (ORCC). To study tentative Ca(2+) regulation of these channels, we attempted to control Ca(2+) levels at the cytoplasmic side of the inside-out membrane patches with Ca(2+)-chelating agents. However, we found that the commonly used Ca(2+)-chelators EGTA and BAPTA by themselves influenced the Cl(-) channel currents, unrelated to their calcium chelating effects. Consequently, in this report we delineate effects of Ca(2+)-chelators (acting from the cytoplasmic side) on the single Cl(-) channel currents in patch-clamp experiments. Using fixed (1-2 mM) concentrations of chelators, two types of Cl(-) channels were identified, as discriminated by their reaction to the Ca(2+)-chelators and by their conductance: true-blockage channels (31 pS) and quasi-blockage channels (52 pS). In true-blockage channels, EGTA and BAPTA inhibited channel activity in a classical flickery type manner. In quasi-blockage channels, chelators significantly shortened the duration of individual openings, as in a flickering block, but the overall channel activity tended to increase. This dual effect of mean open time decrease accompanied by a tendency of open probability to increase we termed a quasi-blockage. Despite the complications due to the chelators as such, we could detect a moderate inhibitory effect of Ca(2+). The anionic classical Cl(-) channel blockers DIDS and SITS could mimic the true/quasi blockage of EGTA and BAPTA. It was concluded that at least in this experimental system, standard techniques for Ca(2+) level control in themselves could fundamentally affect the behaviour of Cl(-) channels.
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Affiliation(s)
- Victor Sabanov
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91, Stockholm, Sweden
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13
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Abstract
Cell cycle-related changes in the ability to regulate cell volume following hyposmotic swelling were studied in mouse fibroblasts using videomicroscopy and the whole-cell patch clamp technique. Regulatory volume decrease (RVD) and volume-sensitive Cl- conductance (G(Cl,vol)) were measured: (1) in proliferating cells of different sizes; (2) in cells arrested in defined phases of the cell cycle (G1, G1/S, S, and M phases) using mevastatin, mimosine, hydroxyurea, aphidicolin, cytosine beta-D-arabinofuranoside, and taxol; and (3) in serum-starved cells (G(0) state). Cells in all groups were able to undergo RVD, although the cells approaching mitosis (i.e., the largest cells in proliferating cultures and the taxol-treated cells) had the lowest rates of shrinkage during RVD. In agreement with this finding, the density of G(Cl,vol) was stable in proliferating and cell cycle-arrested cells for most of the cell cycle, with the exception of the cells approaching mitosis and the new daughter cells where the density was decreased to half. The impairment of RVD was greatest in serum-starved cells which also had the lowest density of G(Cl,vol). We conclude that proliferating cells maintain an ability to recover from osmotic swelling as they progress through the cell cycle, although this ability may be compromised during mitosis.
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Affiliation(s)
- P Doroshenko
- Loeb Health Research Institute, Ottawa Hospital, University of Ottawa, 75 Parkdale Avenue, Ottawa, Ontario, Canada K1Y 4E9.
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Bryan-Sisneros A, Sabanov V, Thoroed SM, Doroshenko P. Dual role of ATP in supporting volume-regulated chloride channels in mouse fibroblasts. Biochim Biophys Acta 2000; 1468:63-72. [PMID: 11018652 DOI: 10.1016/s0005-2736(00)00243-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The effects of inhibitors of protein tyrosine kinases (PTKs) on the Cl(-) current (I(Cl(vol))) through volume-regulated anion/chloride (VRAC) channels whilst manipulating cellular ATP have been studied in mouse fibroblasts using the whole-cell patch clamp technique. Removal of ATP from the pipette-filling solution prevented activation of the current during osmotic cell swelling and when the volume of patched cells was increased by the application of positive pressure through the patch pipette to achieve rates exceeding 100%/min. Equimolar substitution of ATP in the pipette solution with its non-hydrolyzable analogs, adenosine 5'-O-(3-thiotriphosphate) (ATPgammaS) or adenylyl-(beta,gamma-methylene)-diphosphonate (AMP-PCP), not only supported activation of the current but also maintained its amplitude. The PTK inhibitors, tyrphostins A25, B46, 3-amino-2,4-dicyano-5-(4-hydroxyphenyl)penta-2,4-dienonitrile++ + and genistein (all at 100 microM), inhibited I(Cl(vol)) in a time-dependent manner. Tyrphostin A1, which does not inhibit PTK activity, did not affect the current amplitude. The PTK inhibitors also inhibited I(Cl(vol)) under conditions where ATP in the pipette was substituted with ATPgammaS or AMP-PCP. We conclude that in mouse fibroblasts ATP has a dual role in the regulation of the current: it is required for protein phosphorylation to keep VRAC channels operational and, through non-hydrolytic binding, determines the magnitude of I(Cl(vol)). We also suggest that tyrosine-specific protein kinases and phosphatases exhibit an interdependent involvement in the regulation of VRAC channels.
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Affiliation(s)
- A Bryan-Sisneros
- Loeb Health Research Institute, Ottawa University, 725 Parkdale Avenue, K1Y 4E9, Ottawa, Ont., Canada
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Sabanov V, Nedergaard J. Chloride channels in brown adipocyte plasma membranes: candidates for mediation of alpha 1-adrenergic depolarization? Biochem Biophys Res Commun 1995; 211:639-47. [PMID: 7794279 DOI: 10.1006/bbrc.1995.1860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The presence of plasma membrane Cl- channels was investigated in brown-fat cells differentiated in culture. Single channel activity was followed by the patch-clamp technique, with an NMDG+ Cl- pipette solution and a NaCl bath solution. Only rarely was putative Cl- channel activity encountered in the cell-attached mode. However, after excision, ion channel activity of two types was observed in inside-out patches: one type represented the earlier observed non-selective cation channel, and one a putative Cl- channel, with the following characteristics: practically non-rectifying current-voltage relationship with a conductance of approximately 50 pS and a reversal potential of approximately 0 in symmetrical Cl- solutions, voltage dependent channel activity (Po approached 0.5 at positive holding potentials), and rapid flickering activity in the open state. It is discussed whether this Cl- channel may be responsible for the initial depolarization phase observed after alpha 1-adrenergic stimulation of brown-fat cells.
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Affiliation(s)
- V Sabanov
- Wenner-Gren Institute, Arrhenius Laboratories F3, Stockholm University, Sweden
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