1
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Chen JJ, Kaufmann WA, Chen C, Arai I, Kim O, Shigemoto R, Jonas P. Developmental transformation of Ca 2+ channel-vesicle nanotopography at a central GABAergic synapse. Neuron 2024; 112:755-771.e9. [PMID: 38215739 DOI: 10.1016/j.neuron.2023.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 07/12/2023] [Accepted: 12/05/2023] [Indexed: 01/14/2024]
Abstract
The coupling between Ca2+ channels and release sensors is a key factor defining the signaling properties of a synapse. However, the coupling nanotopography at many synapses remains unknown, and it is unclear how it changes during development. To address these questions, we examined coupling at the cerebellar inhibitory basket cell (BC)-Purkinje cell (PC) synapse. Biophysical analysis of transmission by paired recording and intracellular pipette perfusion revealed that the effects of exogenous Ca2+ chelators decreased during development, despite constant reliance of release on P/Q-type Ca2+ channels. Structural analysis by freeze-fracture replica labeling (FRL) and transmission electron microscopy (EM) indicated that presynaptic P/Q-type Ca2+ channels formed nanoclusters throughout development, whereas docked vesicles were only clustered at later developmental stages. Modeling suggested a developmental transformation from a more random to a more clustered coupling nanotopography. Thus, presynaptic signaling developmentally approaches a point-to-point configuration, optimizing speed, reliability, and energy efficiency of synaptic transmission.
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Affiliation(s)
- Jing-Jing Chen
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Chong Chen
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Itaru Arai
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Olena Kim
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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2
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Johnson A, Kaufmann WA, Sommer C, Costanzo T, Dahhan DA, Bednarek SY, Friml J. Three-dimensional visualization of planta clathrin-coated vesicles at ultrastructural resolution. Mol Plant 2022; 15:1533-1542. [PMID: 36081349 DOI: 10.1016/j.molp.2022.09.003] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/18/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Biological systems are the sum of their dynamic three-dimensional (3D) parts. Therefore, it is critical to study biological structures in 3D and at high resolution to gain insights into their physiological functions. Electron microscopy of metal replicas of unroofed cells and isolated organelles has been a key technique to visualize intracellular structures at nanometer resolution. However, many of these methods require specialized equipment and personnel to complete them. Here, we present novel accessible methods to analyze biological structures in unroofed cells and biochemically isolated organelles in 3D and at nanometer resolution, focusing on Arabidopsis clathrin-coated vesicles (CCVs). While CCVs are essential trafficking organelles, their detailed structural information is lacking due to their poor preservation when observed via classical electron microscopy protocols experiments. First, we establish a method to visualize CCVs in unroofed cells using scanning transmission electron microscopy tomography, providing sufficient resolution to define the clathrin coat arrangements. Critically, the samples are prepared directly on electron microscopy grids, removing the requirement to use extremely corrosive acids, thereby enabling the use of this method in any electron microscopy lab. Secondly, we demonstrate that this standardized sample preparation allows the direct comparison of isolated CCV samples with those visualized in cells. Finally, to facilitate the high-throughput and robust screening of metal replicated samples, we provide a deep learning analysis method to screen the "pseudo 3D" morphologies of CCVs imaged with 2D modalities. Collectively, our work establishes accessible ways to examine the 3D structure of biological samples and provide novel insights into the structure of plant CCVs.
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Affiliation(s)
- Alexander Johnson
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria.
| | - Walter A Kaufmann
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Christoph Sommer
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Tommaso Costanzo
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Dana A Dahhan
- UW-Madison, Department of Biochemistry, 433 Babcock Dr., Madison, WI 53706, USA
| | | | - Jiří Friml
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
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3
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Assen FP, Abe J, Hons M, Hauschild R, Shamipour S, Kaufmann WA, Costanzo T, Krens G, Brown M, Ludewig B, Hippenmeyer S, Heisenberg CP, Weninger W, Hannezo E, Luther SA, Stein JV, Sixt M. Multitier mechanics control stromal adaptations in the swelling lymph node. Nat Immunol 2022; 23:1246-1255. [PMID: 35817845 PMCID: PMC9355878 DOI: 10.1038/s41590-022-01257-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 07/29/2021] [Accepted: 06/07/2022] [Indexed: 11/09/2022]
Abstract
Lymph nodes (LNs) comprise two main structural elements: fibroblastic reticular cells that form dedicated niches for immune cell interaction and capsular fibroblasts that build a shell around the organ. Immunological challenge causes LNs to increase more than tenfold in size within a few days. Here, we characterized the biomechanics of LN swelling on the cellular and organ scale. We identified lymphocyte trapping by influx and proliferation as drivers of an outward pressure force, causing fibroblastic reticular cells of the T-zone (TRCs) and their associated conduits to stretch. After an initial phase of relaxation, TRCs sensed the resulting strain through cell matrix adhesions, which coordinated local growth and remodeling of the stromal network. While the expanded TRC network readopted its typical configuration, a massive fibrotic reaction of the organ capsule set in and countered further organ expansion. Thus, different fibroblast populations mechanically control LN swelling in a multitier fashion. Sixt and colleagues show that different fibroblast populations in the lymph node mechanically control its swelling in a multitier fashion.
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Affiliation(s)
- Frank P Assen
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria. .,Department of Dermatology, Medical University Vienna, Vienna, Austria.
| | - Jun Abe
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland
| | - Miroslav Hons
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria.,BIOCEV, First Faculty of Medicine, Charles University, Vestec, Czech Republic
| | - Robert Hauschild
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Shayan Shamipour
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Tommaso Costanzo
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Gabriel Krens
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Markus Brown
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Burkhard Ludewig
- Institute of Immunobiology, Kantonsspital St Gallen, St Gallen, Switzerland
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | | | - Wolfgang Weninger
- Department of Dermatology, Medical University Vienna, Vienna, Austria
| | - Edouard Hannezo
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Sanjiv A Luther
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Jens V Stein
- Department of Oncology, Microbiology and Immunology, University of Fribourg, Fribourg, Switzerland
| | - Michael Sixt
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria.
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4
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Dahhan DA, Reynolds GD, Cárdenas JJ, Eeckhout D, Johnson A, Yperman K, Kaufmann WA, Vang N, Yan X, Hwang I, Heese A, De Jaeger G, Friml J, Van Damme D, Pan J, Bednarek SY. Proteomic characterization of isolated Arabidopsis clathrin-coated vesicles reveals evolutionarily conserved and plant-specific components. Plant Cell 2022; 34:2150-2173. [PMID: 35218346 PMCID: PMC9134090 DOI: 10.1093/plcell/koac071] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/22/2022] [Indexed: 05/26/2023]
Abstract
In eukaryotes, clathrin-coated vesicles (CCVs) facilitate the internalization of material from the cell surface as well as the movement of cargo in post-Golgi trafficking pathways. This diversity of functions is partially provided by multiple monomeric and multimeric clathrin adaptor complexes that provide compartment and cargo selectivity. The adaptor-protein assembly polypeptide-1 (AP-1) complex operates as part of the secretory pathway at the trans-Golgi network (TGN), while the AP-2 complex and the TPLATE complex jointly operate at the plasma membrane to execute clathrin-mediated endocytosis. Key to our further understanding of clathrin-mediated trafficking in plants will be the comprehensive identification and characterization of the network of evolutionarily conserved and plant-specific core and accessory machinery involved in the formation and targeting of CCVs. To facilitate these studies, we have analyzed the proteome of enriched TGN/early endosome-derived and endocytic CCVs isolated from dividing and expanding suspension-cultured Arabidopsis (Arabidopsis thaliana) cells. Tandem mass spectrometry analysis results were validated by differential chemical labeling experiments to identify proteins co-enriching with CCVs. Proteins enriched in CCVs included previously characterized CCV components and cargos such as the vacuolar sorting receptors in addition to conserved and plant-specific components whose function in clathrin-mediated trafficking has not been previously defined. Notably, in addition to AP-1 and AP-2, all subunits of the AP-4 complex, but not AP-3 or AP-5, were found to be in high abundance in the CCV proteome. The association of AP-4 with suspension-cultured Arabidopsis CCVs is further supported via additional biochemical data.
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Affiliation(s)
| | | | - Jessica J Cárdenas
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Dominique Eeckhout
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Alexander Johnson
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | | | - Walter A Kaufmann
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Nou Vang
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Xu Yan
- College Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science & Technology, Pohang 37673, Korea
| | - Antje Heese
- Division of Biochemistry, Interdisciplinary Plant Group, University of Missouri-Columbia, Columbia, Missouri 65211, USA
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Jiří Friml
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Daniël Van Damme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Jianwei Pan
- College Life Sciences, Lanzhou University, Lanzhou 730000, China
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5
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Dahhan DA, Reynolds GD, Cárdenas JJ, Eeckhout D, Johnson A, Yperman K, Kaufmann WA, Vang N, Yan X, Hwang I, Heese A, De Jaeger G, Friml J, Van Damme D, Pan J, Bednarek SY. Proteomic characterization of isolated Arabidopsis clathrin-coated vesicles reveals evolutionarily conserved and plant-specific components. Plant Cell 2022; 34:2150-2173. [PMID: 35218346 DOI: 10.1101/2021.09.16.460678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/22/2022] [Indexed: 05/26/2023]
Abstract
In eukaryotes, clathrin-coated vesicles (CCVs) facilitate the internalization of material from the cell surface as well as the movement of cargo in post-Golgi trafficking pathways. This diversity of functions is partially provided by multiple monomeric and multimeric clathrin adaptor complexes that provide compartment and cargo selectivity. The adaptor-protein assembly polypeptide-1 (AP-1) complex operates as part of the secretory pathway at the trans-Golgi network (TGN), while the AP-2 complex and the TPLATE complex jointly operate at the plasma membrane to execute clathrin-mediated endocytosis. Key to our further understanding of clathrin-mediated trafficking in plants will be the comprehensive identification and characterization of the network of evolutionarily conserved and plant-specific core and accessory machinery involved in the formation and targeting of CCVs. To facilitate these studies, we have analyzed the proteome of enriched TGN/early endosome-derived and endocytic CCVs isolated from dividing and expanding suspension-cultured Arabidopsis (Arabidopsis thaliana) cells. Tandem mass spectrometry analysis results were validated by differential chemical labeling experiments to identify proteins co-enriching with CCVs. Proteins enriched in CCVs included previously characterized CCV components and cargos such as the vacuolar sorting receptors in addition to conserved and plant-specific components whose function in clathrin-mediated trafficking has not been previously defined. Notably, in addition to AP-1 and AP-2, all subunits of the AP-4 complex, but not AP-3 or AP-5, were found to be in high abundance in the CCV proteome. The association of AP-4 with suspension-cultured Arabidopsis CCVs is further supported via additional biochemical data.
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Affiliation(s)
- Dana A Dahhan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Gregory D Reynolds
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Jessica J Cárdenas
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Dominique Eeckhout
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Alexander Johnson
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Klaas Yperman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Walter A Kaufmann
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Nou Vang
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Xu Yan
- College Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science & Technology, Pohang 37673, Korea
| | - Antje Heese
- Division of Biochemistry, Interdisciplinary Plant Group, University of Missouri-Columbia, Columbia, Missouri 65211, USA
| | - Geert De Jaeger
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Jiří Friml
- Institute of Science and Technology (IST Austria), Klosterneuburg 3400, Austria
| | - Daniël Van Damme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium
- VIB Center for Plant Systems Biology, Ghent 9052, Belgium
| | - Jianwei Pan
- College Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Sebastian Y Bednarek
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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6
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Johnson A, Dahhan DA, Gnyliukh N, Kaufmann WA, Zheden V, Costanzo T, Mahou P, Hrtyan M, Wang J, Aguilera-Servin J, van Damme D, Beaurepaire E, Loose M, Bednarek SY, Friml J. The TPLATE complex mediates membrane bending during plant clathrin-mediated endocytosis. Proc Natl Acad Sci U S A 2021; 118:e2113046118. [PMID: 34907016 PMCID: PMC8691179 DOI: 10.1073/pnas.2113046118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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] [Accepted: 11/01/2021] [Indexed: 01/08/2023] Open
Abstract
Clathrin-mediated endocytosis is the major route of entry of cargos into cells and thus underpins many physiological processes. During endocytosis, an area of flat membrane is remodeled by proteins to create a spherical vesicle against intracellular forces. The protein machinery which mediates this membrane bending in plants is unknown. However, it is known that plant endocytosis is actin independent, thus indicating that plants utilize a unique mechanism to mediate membrane bending against high-turgor pressure compared to other model systems. Here, we investigate the TPLATE complex, a plant-specific endocytosis protein complex. It has been thought to function as a classical adaptor functioning underneath the clathrin coat. However, by using biochemical and advanced live microscopy approaches, we found that TPLATE is peripherally associated with clathrin-coated vesicles and localizes at the rim of endocytosis events. As this localization is more fitting to the protein machinery involved in membrane bending during endocytosis, we examined cells in which the TPLATE complex was disrupted and found that the clathrin structures present as flat patches. This suggests a requirement of the TPLATE complex for membrane bending during plant clathrin-mediated endocytosis. Next, we used in vitro biophysical assays to confirm that the TPLATE complex possesses protein domains with intrinsic membrane remodeling activity. These results redefine the role of the TPLATE complex and implicate it as a key component of the evolutionarily distinct plant endocytosis mechanism, which mediates endocytic membrane bending against the high-turgor pressure in plant cells.
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Affiliation(s)
| | - Dana A Dahhan
- Department of Biochemistry, Hector F. DeLuca Laboratories, University of Wisconsin-Madison, Madison, WI 53706
| | | | | | - Vanessa Zheden
- Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Tommaso Costanzo
- Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Pierre Mahou
- CNRS, INSERM, Laboratory for Optics and Biosciences Ecole Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Mónika Hrtyan
- Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Jie Wang
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Center for Plant Systems Biology, 9052 Ghent, Belgium
| | | | - Daniël van Damme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium
- Vlaams Instituut voor Biotechnologie (VIB) Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Emmanuel Beaurepaire
- CNRS, INSERM, Laboratory for Optics and Biosciences Ecole Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Martin Loose
- Institute of Science and Technology, 3400 Klosterneuburg, Austria
| | - Sebastian Y Bednarek
- Department of Biochemistry, Hector F. DeLuca Laboratories, University of Wisconsin-Madison, Madison, WI 53706
| | - Jiří Friml
- Institute of Science and Technology, 3400 Klosterneuburg, Austria;
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7
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Venezia S, Kaufmann WA, Wenning GK, Stefanova N. Toll-like receptor 4 deficiency facilitates α-synuclein propagation and neurodegeneration in a mouse model of prodromal Parkinson's disease. Parkinsonism Relat Disord 2021; 91:59-65. [PMID: 34530328 DOI: 10.1016/j.parkreldis.2021.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 06/21/2021] [Revised: 08/27/2021] [Accepted: 09/08/2021] [Indexed: 01/24/2023]
Abstract
The evidence linking innate immunity mechanisms and neurodegenerative diseases is growing, but the specific mechanisms are incompletely understood. Experimental data suggest that microglial TLR4 mediates the uptake and clearance of α-synuclein also termed synucleinophagy. The accumulation of misfolded α-synuclein throughout the brain is central to Parkinson's disease (PD). The distribution and progression of the pathology is often attributed to the propagation of α-synuclein. Here, we apply a classical α-synuclein propagation model of prodromal PD in wild type and TLR4 deficient mice to study the role of TLR4 in the progression of the disease. Our data suggest that TLR4 deficiency facilitates the α-synuclein seed spreading associated with reduced lysosomal activity of microglia. Three months after seed inoculation, more pronounced proteinase K-resistant α-synuclein inclusion pathology is observed in mice with TLR4 deficiency. The facilitated propagation of α-synuclein is associated with early loss of dopamine transporter (DAT) signal in the striatum and loss of dopaminergic neurons in substantia nigra pars compacta of TLR4 deficient mice. These new results support TLR4 signaling as a putative target for disease modification to slow the progression of PD and related disorders.
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Affiliation(s)
- Serena Venezia
- Laboratory for Translational Neurodegeneration Research, Division of Neurobiology, Department of Neurology, Medical University of Innsbruck, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Gregor K Wenning
- Laboratory for Translational Neurodegeneration Research, Division of Neurobiology, Department of Neurology, Medical University of Innsbruck, Austria
| | - Nadia Stefanova
- Laboratory for Translational Neurodegeneration Research, Division of Neurobiology, Department of Neurology, Medical University of Innsbruck, Austria.
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8
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Schöpf CL, Ablinger C, Geisler SM, Stanika RI, Campiglio M, Kaufmann WA, Nimmervoll B, Schlick B, Brockhaus J, Missler M, Shigemoto R, Obermair GJ. Presynaptic α 2δ subunits are key organizers of glutamatergic synapses. Proc Natl Acad Sci U S A 2021; 118:e1920827118. [PMID: 33782113 PMCID: PMC8040823 DOI: 10.1073/pnas.1920827118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [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] [Indexed: 01/04/2023] Open
Abstract
In nerve cells the genes encoding for α2δ subunits of voltage-gated calcium channels have been linked to synaptic functions and neurological disease. Here we show that α2δ subunits are essential for the formation and organization of glutamatergic synapses. Using a cellular α2δ subunit triple-knockout/knockdown model, we demonstrate a failure in presynaptic differentiation evidenced by defective presynaptic calcium channel clustering and calcium influx, smaller presynaptic active zones, and a strongly reduced accumulation of presynaptic vesicle-associated proteins (synapsin and vGLUT). The presynaptic defect is associated with the downscaling of postsynaptic AMPA receptors and the postsynaptic density. The role of α2δ isoforms as synaptic organizers is highly redundant, as each individual α2δ isoform can rescue presynaptic calcium channel trafficking and expression of synaptic proteins. Moreover, α2δ-2 and α2δ-3 with mutated metal ion-dependent adhesion sites can fully rescue presynaptic synapsin expression but only partially calcium channel trafficking, suggesting that the regulatory role of α2δ subunits is independent from its role as a calcium channel subunit. Our findings influence the current view on excitatory synapse formation. First, our study suggests that postsynaptic differentiation is secondary to presynaptic differentiation. Second, the dependence of presynaptic differentiation on α2δ implicates α2δ subunits as potential nucleation points for the organization of synapses. Finally, our results suggest that α2δ subunits act as transsynaptic organizers of glutamatergic synapses, thereby aligning the synaptic active zone with the postsynaptic density.
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Affiliation(s)
- Clemens L Schöpf
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Cornelia Ablinger
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Stefanie M Geisler
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Department of Pharmacology and Toxicology, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Ruslan I Stanika
- Division of Physiology, Karl Landsteiner University of Health Sciences, A-3500 Krems, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Benedikt Nimmervoll
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Bettina Schlick
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Gerald J Obermair
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria;
- Division of Physiology, Karl Landsteiner University of Health Sciences, A-3500 Krems, Austria
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9
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Li H, von Wangenheim D, Zhang X, Tan S, Darwish‐Miranda N, Naramoto S, Wabnik K, De Rycke R, Kaufmann WA, Gütl D, Tejos R, Grones P, Ke M, Chen X, Dettmer J, Friml J. Cellular requirements for PIN polar cargo clustering in Arabidopsis thaliana. New Phytol 2021; 229:351-369. [PMID: 32810889 PMCID: PMC7984064 DOI: 10.1111/nph.16887] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/07/2020] [Indexed: 05/12/2023]
Abstract
Cell and tissue polarization is fundamental for plant growth and morphogenesis. The polar, cellular localization of Arabidopsis PIN-FORMED (PIN) proteins is crucial for their function in directional auxin transport. The clustering of PIN polar cargoes within the plasma membrane has been proposed to be important for the maintenance of their polar distribution. However, the more detailed features of PIN clusters and the cellular requirements of cargo clustering remain unclear. Here, we characterized PIN clusters in detail by means of multiple advanced microscopy and quantification methods, such as 3D quantitative imaging or freeze-fracture replica labeling. The size and aggregation types of PIN clusters were determined by electron microscopy at the nanometer level at different polar domains and at different developmental stages, revealing a strong preference for clustering at the polar domains. Pharmacological and genetic studies revealed that PIN clusters depend on phosphoinositol pathways, cytoskeletal structures and specific cell-wall components as well as connections between the cell wall and the plasma membrane. This study identifies the role of different cellular processes and structures in polar cargo clustering and provides initial mechanistic insight into the maintenance of polarity in plants and other systems.
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Affiliation(s)
- Hongjiang Li
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and BioinformaticsGhent UniversityGhent9052Belgium
| | - Daniel von Wangenheim
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
- Centre for Plant Integrative BiologySchool of BiosciencesUniversity of NottinghamLoughboroughLE12 5RDUK
| | - Xixi Zhang
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
- Department of Applied Genetics and Cell BiologyUniversity of Natural Resources and Life Sciences (BOKU)Vienna1190Austria
| | - Shutang Tan
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
| | | | - Satoshi Naramoto
- Graduate School of Life SciencesTohoku UniversitySendai980‐8577Japan
| | - Krzysztof Wabnik
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and BioinformaticsGhent UniversityGhent9052Belgium
| | - Riet De Rycke
- Department of Plant Biotechnology and BioinformaticsGhent UniversityGhent9052Belgium
- VIB Center for Plant Systems BiologyGhent9052Belgium
- Expertise Centre for Transmission Electron Microscopy and VIB BioImaging CoreGhent UniversityGhent9052Belgium
| | - Walter A. Kaufmann
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
| | - Daniel Gütl
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
| | - Ricardo Tejos
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and BioinformaticsGhent UniversityGhent9052Belgium
- Departamento de BiologíaFacultad de CienciasCentro de Biología Molecular VegetalUniversidad de ChileSantiago7800003Chile
| | - Peter Grones
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
| | - Meiyu Ke
- Haixia Institute of Science and TechnologyFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Xu Chen
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and BioinformaticsGhent UniversityGhent9052Belgium
- Haixia Institute of Science and TechnologyFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Jan Dettmer
- Department of Plant Systems Biology, VIB and Department of Plant Biotechnology and BioinformaticsGhent UniversityGhent9052Belgium
| | - Jiří Friml
- Institute of Science and Technology Austria (IST Austria)Klosterneuburg3400Austria
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10
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Johnson A, Gnyliukh N, Kaufmann WA, Narasimhan M, Vert G, Bednarek SY, Friml J. Experimental toolbox for quantitative evaluation of clathrin-mediated endocytosis in the plant model Arabidopsis. J Cell Sci 2020; 133:jcs248062. [PMID: 32616560 DOI: 10.1242/jcs.248062] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/22/2020] [Indexed: 12/29/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) is a crucial cellular process implicated in many aspects of plant growth, development, intra- and intercellular signaling, nutrient uptake and pathogen defense. Despite these significant roles, little is known about the precise molecular details of how CME functions in planta To facilitate the direct quantitative study of plant CME, we review current routinely used methods and present refined, standardized quantitative imaging protocols that allow the detailed characterization of CME at multiple scales in plant tissues. These protocols include: (1) an efficient electron microscopy protocol for the imaging of Arabidopsis CME vesicles in situ, thus providing a method for the detailed characterization of the ultrastructure of clathrin-coated vesicles; (2) a detailed protocol and analysis for quantitative live-cell fluorescence microscopy to precisely examine the temporal interplay of endocytosis components during single CME events; (3) a semi-automated analysis to allow the quantitative characterization of global internalization of cargos in whole plant tissues; and (4) an overview and validation of useful genetic and pharmacological tools to interrogate the molecular mechanisms and function of CME in intact plant samples.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Alexander Johnson
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Nataliia Gnyliukh
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | | | - Grégory Vert
- Plant Science Research Laboratory (LRSV), UMR5546 CNRS/Université Toulouse 3, 24 chemin de Borde Rouge, 31320 Auzeville Tolosane, France
| | | | - Jiří Friml
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
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11
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Reipert S, Goldammer H, Richardson C, Goldberg MW, Hawkins TJ, Hollergschwandtner E, Kaufmann WA, Antreich S, Stierhof YD. Agitation Modules: Flexible Means to Accelerate Automated Freeze Substitution. J Histochem Cytochem 2018; 66:903-921. [PMID: 29969056 DOI: 10.1369/0022155418786698] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
For ultrafast fixation of biological samples to avoid artifacts, high-pressure freezing (HPF) followed by freeze substitution (FS) is preferred over chemical fixation at room temperature. After HPF, samples are maintained at low temperature during dehydration and fixation, while avoiding damaging recrystallization. This is a notoriously slow process. McDonald and Webb demonstrated, in 2011, that sample agitation during FS dramatically reduces the necessary time. Then, in 2015, we (H.G. and S.R.) introduced an agitation module into the cryochamber of an automated FS unit and demonstrated that the preparation of algae could be shortened from days to a couple of hours. We argued that variability in the processing, reproducibility, and safety issues are better addressed using automated FS units. For dissemination, we started low-cost manufacturing of agitation modules for two of the most widely used FS units, the Automatic Freeze Substitution Systems, AFS(1) and AFS2, from Leica Microsystems, using three dimensional (3D)-printing of the major components. To test them, several labs independently used the modules on a wide variety of specimens that had previously been processed by manual agitation, or without agitation. We demonstrate that automated processing with sample agitation saves time, increases flexibility with respect to sample requirements and protocols, and produces data of at least as good quality as other approaches.
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Affiliation(s)
- Siegfried Reipert
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - Helmuth Goldammer
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | | | - Martin W Goldberg
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Timothy J Hawkins
- Department of Biosciences, Durham University, Durham, United Kingdom
| | | | - Walter A Kaufmann
- Electron Microscopy Facility, Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Sebastian Antreich
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - York-Dieter Stierhof
- Center for Plant Molecular Biology (ZMBP), Microscopy, University of Tübingen, Tübingen, Germany
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12
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Weis C, Kaufmann WA, Humpel C. Lipid-Mediated In Vivo Gene Transfer Replaces the Loss of Choline Acetyltransferase Activity after Unilateral Fimbria-Fornix Aspiration. Cell Transplant 2017. [DOI: 10.3727/000000001783986233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Carla Weis
- Laboratory of Psychiatry, Clinic of Psychiatry, University Hospital Innsbruck, Austria
| | - Walter A. Kaufmann
- Laboratory of Psychiatry, Clinic of Psychiatry, University Hospital Innsbruck, Austria
| | - Christian Humpel
- Laboratory of Psychiatry, Clinic of Psychiatry, University Hospital Innsbruck, Austria
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13
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Grones P, Chen X, Simon S, Kaufmann WA, De Rycke R, Nodzyński T, Zažímalová E, Friml J. Auxin-binding pocket of ABP1 is crucial for its gain-of-function cellular and developmental roles. J Exp Bot 2015; 66:5055-65. [PMID: 25922490 DOI: 10.1093/jxb/erv177] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [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: 05/11/2023]
Abstract
The plant hormone auxin is a key regulator of plant growth and development. Auxin levels are sensed and interpreted by distinct receptor systems that activate a broad range of cellular responses. The Auxin-Binding Protein1 (ABP1) that has been identified based on its ability to bind auxin with high affinity is a prime candidate for the extracellular receptor responsible for mediating a range of auxin effects, in particular, the fast non-transcriptional ones. Contradictory genetic studies suggested prominent or no importance of ABP1 in many developmental processes. However, how crucial the role of auxin binding to ABP1 is for its functions has not been addressed. Here, we show that the auxin-binding pocket of ABP1 is essential for its gain-of-function cellular and developmental roles. In total, 16 different abp1 mutants were prepared that possessed substitutions in the metal core or in the hydrophobic amino acids of the auxin-binding pocket as well as neutral mutations. Their analysis revealed that an intact auxin-binding pocket is a prerequisite for ABP1 to activate downstream components of the ABP1 signalling pathway, such as Rho of Plants (ROPs) and to mediate the clathrin association with membranes for endocytosis regulation. In planta analyses demonstrated the importance of the auxin binding pocket for all known ABP1-mediated postembryonic developmental processes, including morphology of leaf epidermal cells, root growth and root meristem activity, and vascular tissue differentiation. Taken together, these findings suggest that auxin binding to ABP1 is central to its function, supporting the role of ABP1 as auxin receptor.
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Affiliation(s)
- Peter Grones
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Bioinformatics, Ghent University, BE-9052 Gent, Belgium
| | - Xu Chen
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Bioinformatics, Ghent University, BE-9052 Gent, Belgium
| | - Sibu Simon
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB) and Department of Plant Biotechnology and Bioinformatics, Ghent University, BE-9052 Gent, Belgium
| | - Walter A Kaufmann
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria
| | - Riet De Rycke
- VIB Department for Molecular Biomedical Research, VIB, 9052 Gent, Belgium
| | - Tomasz Nodzyński
- Mendel Centre for Plant Genomics and Proteomics, Masaryk University, CEITEC MU, CZ-625 00 Brno, Czech Republic
| | - Eva Zažímalová
- Institute of Experimental Botany of the Academy of Sciences of the Czech Republic, 165 02 Prague, Czech Republic
| | - Jiří Friml
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria
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14
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Mansouri M, Kasugai Y, Fukazawa Y, Bertaso F, Raynaud F, Perroy J, Fagni L, Kaufmann WA, Watanabe M, Shigemoto R, Ferraguti F. Distinct subsynaptic localization of type 1 metabotropic glutamate receptors at glutamatergic and
GABA
ergic synapses in the rodent cerebellar cortex. Eur J Neurosci 2014; 41:157-67. [DOI: 10.1111/ejn.12779] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 09/26/2014] [Accepted: 10/05/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Mahnaz Mansouri
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | - Yu Kasugai
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | - Yugo Fukazawa
- Division of Cerebral Structure National Institute for Physiological Sciences Okazaki Japan
| | - Federica Bertaso
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Fabrice Raynaud
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Julie Perroy
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Laurent Fagni
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Walter A. Kaufmann
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | | | - Ryuichi Shigemoto
- Division of Cerebral Structure National Institute for Physiological Sciences Okazaki Japan
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15
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Schmiedinger T, Vogel GF, Eiter O, Pfaller K, Kaufmann WA, Flörl A, Gutleben K, Schönherr S, Witting B, Lechleitner TW, Ebner HL, Seppi T, Hess MW. Cryo-immunoelectron microscopy of adherent cells improved by the use of electrospun cell culture substrates. Traffic 2013; 14:886-94. [PMID: 23631675 DOI: 10.1111/tra.12080] [Citation(s) in RCA: 7] [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: 11/20/2012] [Revised: 04/25/2013] [Accepted: 04/30/2013] [Indexed: 01/27/2023]
Abstract
Electrospun nanofibres are an excellent cell culture substrate, enabling the fast and non-disruptive harvest and transfer of adherent cells for microscopical and biochemical analyses. Metabolic activity and cellular structures are maintained during the only half a minute-long harvest and transfer process. We show here that such samples can be optimally processed by means of cryofixation combined either with freeze-substitution, sample rehydration and cryosection-immunolabelling or with freeze-fracture replica-immunolabelling. Moreover, electrospun fibre substrates are equally suitable for complementary approaches, such as biochemistry, fluorescence microscopy and cytochemistry.
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Affiliation(s)
- Thomas Schmiedinger
- Department of Therapeutic Radiology and Oncology, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria
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16
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Kaufmann WA, Matsui K, Jeromin A, Nerbonne JM, Ferraguti F. Kv4.2 potassium channels segregate to extrasynaptic domains and influence intrasynaptic NMDA receptor NR2B subunit expression. Brain Struct Funct 2012; 218:1115-32. [PMID: 22932868 PMCID: PMC3748322 DOI: 10.1007/s00429-012-0450-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 08/08/2012] [Indexed: 12/23/2022]
Abstract
Neurons of the intercalated cell clusters (ITCs) represent an important relay site for information flow within amygdala nuclei. These neurons receive mainly glutamatergic inputs from the basolateral amygdala at their dendritic domains and provide feed-forward inhibition to the central nucleus. Voltage-gated potassium channels type-4.2 (Kv4.2) are main players in dendritic signal processing and integration providing a key component of the A currents. In this study, the subcellular localization and distribution of the Kv4.2 was studied in ITC neurons by means of light- and electron microscopy, and compared to other types of central principal neurons. Several ultrastructural immunolocalization techniques were applied including pre-embedding techniques and, most importantly, SDS-digested freeze-fracture replica labeling. We found Kv4.2 densely expressed in somato-dendritic domains of ITC neurons where they show a differential distribution pattern as revealed by nearest neighbor analysis. Comparing ITC neurons with hippocampal pyramidal and cerebellar granule cells, a cell type- and domain-dependent organization in Kv4.2 distribution was observed. Kv4.2 subunits were localized to extrasynaptic sites where they were found to influence intrasynaptic NMDA receptor subunit expression. In samples of Kv4.2 knockout mice, the frequency of NR1-positive synapses containing the NR2B subunit was significantly increased. This indicates a strong, yet indirect effect of Kv4.2 on the synaptic content of NMDA receptor subtypes, and a likely role in synaptic plasticity at ITC neurons.
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Affiliation(s)
- Walter A Kaufmann
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr Strasse 1a, 6020 Innsbruck, Austria.
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17
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Stefanova N, Kaufmann WA, Humpel C, Poewe W, Wenning GK. Systemic proteasome inhibition triggers neurodegeneration in a transgenic mouse model expressing human α-synuclein under oligodendrocyte promoter: implications for multiple system atrophy. Acta Neuropathol 2012; 124:51-65. [PMID: 22491959 PMCID: PMC3377902 DOI: 10.1007/s00401-012-0977-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [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: 09/15/2011] [Revised: 03/23/2012] [Accepted: 03/25/2012] [Indexed: 12/24/2022]
Abstract
Multiple system atrophy (MSA) is a progressive late onset neurodegenerative α-synucleinopathy with unclear pathogenesis. Recent genetic and pathological studies support a central role of α-synuclein (αSYN) in MSA pathogenesis. Oligodendroglial cytoplasmic inclusions of fibrillar αSYN and dysfunction of the ubiquitin–proteasome system are suggestive of proteolytic stress in this disorder. To address the possible pathogenic role of oligodendroglial αSYN accumulation and proteolytic failure in MSA we applied systemic proteasome inhibition (PSI) in transgenic mice with oligodendroglial human αSYN expression and determined the presence of MSA-like neurodegeneration in this model as compared to wild-type mice. PSI induced open field motor disability in transgenic αSYN mice but not in wild-type mice. The motor phenotype corresponded to progressive and selective neuronal loss in the striatonigral and olivopontocerebellar systems of PSI-treated transgenic αSYN mice. In contrast no neurodegeneration was detected in PSI-treated wild-type controls. PSI treatment of transgenic αSYN mice was associated with significant ultrastructural alterations including accumulation of fibrillar human αSYN in the cytoplasm of oligodendroglia, which resulted in myelin disruption and demyelination characterized by increased g-ratio. The oligodendroglial and myelin pathology was accompanied by axonal degeneration evidenced by signs of mitochondrial stress and dysfunctional axonal transport in the affected neurites. In summary, we provide new evidence supporting a primary role of proteolytic failure and suggesting a neurodegenerative pathomechanism related to disturbed oligodendroglial/myelin trophic support in the pathogenesis of MSA.
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Affiliation(s)
- Nadia Stefanova
- Division of Neurobiology, Innsbruck Medical University, Innsbruck, Austria.
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18
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Willis M, Kaufmann WA, Wietzorrek G, Hutter-Paier B, Moosmang S, Humpel C, Hofmann F, Windisch M, Knaus HG, Marksteiner J. L-type calcium channel CaV 1.2 in transgenic mice overexpressing human AbetaPP751 with the London (V717I) and Swedish (K670M/N671L) mutations. J Alzheimers Dis 2010; 20:1167-80. [PMID: 20413896 DOI: 10.3233/jad-2010-091117] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cumulative evidence indicates that amyloid-beta peptides exert some of their neurodegenerative effects through modulation of L-type voltage gated calcium channels, which play key roles in a diverse range of CNS functions. In this study we examined the expression of CaV1.2 L-type voltage gated calcium channels in transgenic mice overexpressing human AbetaPP751 with the London (V717I) and Swedish (K670M/N671L) mutations by immunohistochemistry in light and electron microscopy. In hippocampal layers of wild type and transgenic mice, CaV1.2 channels were predominantly localized to somato-dendritic domains of neurons, and to astrocytic profiles with an age-dependent increase in labeling density. In transgenic animals, CaV1.2-like immunoreactive clusters were found in neuronal profiles in association with amyloid-beta plaques. Both the number and density of these clusters depended upon age of animals and number of plaques. The most striking difference between wild type and transgenic mice was the age-dependent expression of CaV1.2 channels in reactive astrocytes. At the age of 6 month, CaV1.2 channels were rarely detected in reactive astrocytes of transgenic mice, but an incremental number of CaV1.2 expressing reactive astrocytes was found with increasing age of animals and number of amyloid-beta plaques. This study demonstrates that CaV1.2 channels are highly expressed in reactive astrocytes of 12-months of age transgenic mice, which might be a consequence of the increasing amyloid burden. Further studies should clarify which functional implications are associated with the higher availability of CaV1.2 channels in late stage Alzheimer's disease.
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Affiliation(s)
- Michael Willis
- Department of Psychiatry and Psychotherapy, University Clinic of General and Social Psychiatry, Innsbruck Medical University, Innsbruck, Austria
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19
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Kaufmann WA, Kasugai Y, Ferraguti F, Storm JF. Two distinct pools of large-conductance calcium-activated potassium channels in the somatic plasma membrane of central principal neurons. Neuroscience 2010; 169:974-86. [PMID: 20595025 PMCID: PMC2923744 DOI: 10.1016/j.neuroscience.2010.05.070] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 05/26/2010] [Accepted: 05/27/2010] [Indexed: 01/07/2023]
Abstract
Although nerve cell membranes are often assumed to be uniform with respect to electrical properties, there is increasing evidence for compartmentalization into subdomains with heterogeneous impacts on the overall cell function. Such microdomains are characterized by specific sets of proteins determining their functional properties. Recently, clustering of large-conductance calcium-activated potassium (BKCa) channels was shown at sites of subsurface membrane cisterns in cerebellar Purkinje cells (PC), where they likely participate in building a subcellular signaling unit, the 'PLasmERosome'. By applying SDS-digested freeze-fracture replica labeling (SDS-FRL) and postembedding immunogold electron microscopy, we have now studied the spatial organization of somatic BKCa channels in neocortical layer 5 pyramidal neurons, principal neurons of the central and basolateral amygdaloid nuclei, hippocampal pyramidal neurons and dentate gyrus (DG) granule cells to establish whether there is a common organizational principle in the distribution of BKCa channels in central principal neurons. In all cell types analyzed, somatic BKCa channels were found to be non-homogenously distributed in the plasma membrane, forming two pools of channels with one pool consisting of clustered channels and the other of scattered channels in the extrasynaptic membrane. Quantitative analysis by means of SDS-FRL revealed that about two-thirds of BKCa channels belong to the scattered pool and about one-third to the clustered pool in principal cell somata. Overall densities of channels in both pools differed in the different cell types analyzed, although being considerably lower compared to cerebellar PC. Postembedding immunogold labeling revealed association of clustered channels with subsurface membrane cisterns and confirmed extrasynaptic localization of scattered channels. This study indicates a common organizational principle for somatic BKCa channels in central principal neurons with the formation of a clustered and a scattered pool of channels, and a cell-type specific density of this channel type.
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Affiliation(s)
- W A Kaufmann
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr Strasse 1a, 6020 Innsbruck, Austria.
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20
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Subramanyam P, Obermair GJ, Baumgartner S, Gebhart M, Striessnig J, Kaufmann WA, Geley S, Flucher BE. Activity and calcium regulate nuclear targeting of the calcium channel beta4b subunit in nerve and muscle cells. Channels (Austin) 2009; 3:343-55. [PMID: 19755859 PMCID: PMC2853709 DOI: 10.4161/chan.3.5.9696] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [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] [Indexed: 01/27/2023] Open
Abstract
Auxiliary beta subunits are critical determinants of membrane expression and gating properties of voltage-gated calcium channels. Mutations in the beta(4) subunit gene cause ataxia and epilepsy. However, the specific function of beta(4) in neurons and its causal relation to neurological diseases are unknown. Here we report the localization of the beta(4) subunit in the nuclei of cerebellar granule and Purkinje cells. beta(4b) was the only beta isoform showing nuclear targeting when expressed in neurons and skeletal myotubes. Its specific nuclear targeting property was mapped to an N-terminal double-arginine motif, which was necessary and sufficient for targeting beta subunits into the nucleus. Spontaneous electrical activity and calcium influx negatively regulated beta(4b) nuclear localization by a CRM-1-dependent nuclear export mechanism. The activity-dependent shuttling of beta(4b) into and out of the nucleus indicates a specific role of this beta subunit in neurons, in communicating the activity of calcium channels to the nucleus.
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Affiliation(s)
- Prakash Subramanyam
- Department of Physiology and Medical Physics; Division of Physiology; Medical University Innsbruck; Innsbruck, Austria
| | - Gerald J. Obermair
- Department of Physiology and Medical Physics; Division of Physiology; Medical University Innsbruck; Innsbruck, Austria
| | - Sabine Baumgartner
- Department of Physiology and Medical Physics; Division of Physiology; Medical University Innsbruck; Innsbruck, Austria
| | - Mathias Gebhart
- Biocenter; Section of Molecular Pathophysiology; Medical University Innsbruck; Innsbruck, Austria
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology; Institute of Pharmacy; University of Innsbruck; Innsbruck, Austria
| | - Walter A. Kaufmann
- Department of Pharmacology; Medical University Innsbruck; Innsbruck, Austria
| | - Stephan Geley
- Biocenter; Section of Molecular Pathophysiology; Medical University Innsbruck; Innsbruck, Austria
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics; Division of Physiology; Medical University Innsbruck; Innsbruck, Austria
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21
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Kaufmann WA, Ferraguti F, Fukazawa Y, Kasugai Y, Shigemoto R, Laake P, Sexton JA, Ruth P, Wietzorrek G, Knaus HG, Storm JF, Ottersen OP. Large-conductance calcium-activated potassium channels in purkinje cell plasma membranes are clustered at sites of hypolemmal microdomains. J Comp Neurol 2009; 515:215-30. [PMID: 19412945 DOI: 10.1002/cne.22066] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Calcium-activated potassium channels have been shown to be critically involved in neuronal function, but an elucidation of their detailed roles awaits identification of the microdomains where they are located. This study was undertaken to unravel the precise subcellular distribution of the large-conductance calcium-activated potassium channels (called BK, KCa1.1, or Slo1) in the somatodendritic compartment of cerebellar Purkinje cells by means of postembedding immunogold cytochemistry and SDS-digested freeze-fracture replica labeling (SDS-FRL). We found BK channels to be unevenly distributed over the Purkinje cell plasma membrane. At distal dendritic compartments, BK channels were scattered over the plasma membrane of dendritic shafts and spines but absent from postsynaptic densities. At the soma and proximal dendrites, BK channels formed two distinct pools. One pool was scattered over the plasma membrane, whereas the other pool was clustered in plasma membrane domains overlying subsurface cisterns. The labeling density ratio of clustered to scattered channels was about 60:1, established in SDS-FRL. Subsurface cisterns, also called hypolemmal cisterns, are subcompartments of the endoplasmic reticulum likely representing calciosomes that unload and refill Ca2+ independently. Purkinje cell subsurface cisterns are enriched in inositol 1,4,5-triphosphate receptors that mediate the effects of several neurotransmitters, hormones, and growth factors by releasing Ca2+ into the cytosol, generating local Ca2+ sparks. Such increases in cytosolic [Ca2+] may be sufficient for BK channel activation. Clustered BK channels in the plasma membrane may thus participate in building a functional unit (plasmerosome) with the underlying calciosome that contributes significantly to local signaling in Purkinje cells.
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Affiliation(s)
- Walter A Kaufmann
- Department of Pharmacology, Innsbruck Medical University, 6020 Innsbruck, Austria.
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Kaufmann WA, Ferraguti F, Fukazawa Y, Kasugai Y, Shigemoto R, Laake P, Sexton JA, Ruth P, Wietzorrek G, Knaus HG, Storm JF, Ottersen OP. BK channels in Purkinje cell plasma membranes are concentrated in plasmerosomes at sites of hypolemmal cisternae. BMC Pharmacol 2008. [PMCID: PMC3313227 DOI: 10.1186/1471-2210-8-s1-a37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Geracitano R, Kaufmann WA, Szabo G, Ferraguti F, Capogna M. Synaptic heterogeneity between mouse paracapsular intercalated neurons of the amygdala. J Physiol 2007; 585:117-34. [PMID: 17916608 DOI: 10.1113/jphysiol.2007.142570] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
GABAergic medial paracapsular intercalated (Imp) neurons of amygdala are thought of as playing a central role in fear learning and extinction. We report here that the synaptic network formed by these neurons exhibits distinct short-term plastic synaptic responses. The success rate of synaptic events evoked at a frequency range of 0.1-10 Hz varied dramatically between different connected cell pairs. Upon enhancing the frequency of stimulation, the success rate increased, decreased or remained constant, in a similar number of cell pairs. Such synaptic heterogeneity resulted in inhibition of the firing of the postsynaptic neurons with different efficacies. Moreover, we found that the different synaptic weights were mainly determined by diversity in presynaptic release probabilities rather than postsynaptic changes. Sequential paired recording experiments demonstrated that the same presynaptic neuron established the same type of synaptic connections with different postsynaptic neurons, suggesting the absence of target-cell specificity. Conversely, the same postsynaptic neuron was contacted by different types of synaptic connections formed by different presynaptic neurons. A detailed anatomical analysis of the recorded neurons revealed discrete and unexpected peculiarities in the dendritic and axonal patterns of different cell pairs. In contrast, several intrinsic electrophysiological responses were homogeneous among neurons, and synaptic failure counts were not affected by presynaptic cannabinoid 1 or GABA B receptors. We propose that the heterogeneous functional connectivity of Imp neurons, demonstrated by this study, is required to maintain the stability of firing patterns which is critical for the computational role of the amygdala in fear learning and extinction.
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Sailer CA, Kaufmann WA, Kogler M, Chen L, Sausbier U, Ottersen OP, Ruth P, Shipston MJ, Knaus HG. Immunolocalization of BK channels in hippocampal pyramidal neurons. Eur J Neurosci 2006; 24:442-54. [PMID: 16903852 DOI: 10.1111/j.1460-9568.2006.04936.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neurons are highly specialized cells in which the integration and processing of electrical signals critically depends on the precise localization of ion channels. For large-conductance Ca(2+)- activated K(+) (BK) channels, targeting to presynaptic membranes in hippocampal pyramidal cells was reported; however, functional evidence also suggests a somatodendritic localization. Therefore we re-examined the subcellular distribution of BK channels in mouse hippocampus using a panel of independent antibodies in a combined approach of conventional immunocytochemistry on cultured neurons, pre- and postembedding electron microscopy and immunoprecipitation. In cultured murine hippocampal neurons, the colocalization of BK channels with both pre- and postsynaptic marker proteins was observed. Electron microscopy confirmed targeting of BK channels to axonal as well as dendritic membranes of glutamatergic synapses in hippocampus. A postsynaptic localization of BK channels was also supported by the finding that the channel coimmunoprecipitated with PSD95, a protein solely expressed in the postsynaptic compartment. These results thus demonstrate that BK channels reside in both post- and presynaptic compartments of hippocampal pyramidal neurons.
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Affiliation(s)
- Claudia A Sailer
- Department of Medical Genetics, Molecular and Clinical Pharmacology, Division for Molecular and Cellular Pharmacology, Medical University Innsbruck, Peter-Mayr Strasse 1, 6020 Innsbruck, Austria
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Sailer CA, Kaufmann WA, Marksteiner J, Knaus HG. Comparative immunohistochemical distribution of three small-conductance Ca2+-activated potassium channel subunits, SK1, SK2, and SK3 in mouse brain. Mol Cell Neurosci 2004; 26:458-69. [PMID: 15234350 DOI: 10.1016/j.mcn.2004.03.002] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [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: 12/15/2003] [Revised: 02/27/2004] [Accepted: 03/02/2004] [Indexed: 11/22/2022] Open
Abstract
To investigate the distribution of all three SK channel subunits in the mouse central nervous system, we performed immunohistochemistry using sequence-specific antibodies directed against SK1, SK2, and SK3 proteins. Expression of SK1 and SK2 proteins revealed a partly overlapping distribution pattern restricted to a limited number of brain areas (e.g., neocortex, hippocampal formation). In contrast, SK3 immunoreactivity was rather complementary and predominantly detected in phylogenetically older brain regions like basal ganglia, thalamus, and various brain stem nuclei (e.g., locus coeruleus, tegmental nuclei). At the cellular level, SK1- and SK2-like immunoreactivity was primarily localized to somatic and dendritic structures, whereas the majority of SK3-like immunoreactivity was associated with varicose fibers.
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Affiliation(s)
- Claudia A Sailer
- Institute for Biochemical Pharmacology, Medical University Innsbruck, A-6020 Innsbruck, Austria
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Abstract
Based on electrophysiological studies, Ca(2+)-activated K(+) channels and voltage-gated Ca(2+) channels appear to be located in close proximity in neurons. Such colocalization would ensure selective and rapid activation of K(+) channels by local increases in the cytosolic calcium concentration. The nature of the apparent coupling is not known. In the present study we report a direct coassembly of big conductance Ca(2+)-activated K(+) channels (BK) and L-type voltage-gated Ca(2+) channels in rat brain. Saturation immunoprecipitation studies were performed on membranes labeled for BK channels and precipitated with antibodies against alpha(1C) and alpha(1D) L-type Ca(2+) channels. To confirm the specificity of the interaction, precipitation experiments were carried out also in reverse order. Also, additive precipitation was performed because alpha(1C) and alpha(1D) L-type Ca(2+) channels always refer to separate ion channel complexes. Finally, immunochemical studies showed a distinct but overlapping expression pattern of the two types of ion channels investigated. BK and L-type Ca(2+) channels were colocalized in various compartments throughout the rat brain. Taken together, these results demonstrate a direct coassembly of BK channels and L-type Ca(2+) channels in certain areas of the brain.
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Affiliation(s)
- Morten Grunnet
- Department of Medical Physiology, the Panum Institute, University of Copenhagen, Blegdamsvej 3, Copenhagen DK-2200, Denmark.
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27
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Lechner T, Adlassnig C, Humpel C, Kaufmann WA, Maier H, Reinstadler-Kramer K, Hinterhölzl J, Mahata SK, Jellinger KA, Marksteiner J. Chromogranin peptides in Alzheimer's disease. Exp Gerontol 2004; 39:101-13. [PMID: 14724070 DOI: 10.1016/j.exger.2003.09.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Synaptic disturbances may play a key role in the pathophysiology of Alzheimer's disease. To characterize differential synaptic alterations in the brains of Alzheimer patients, chromogranin A, chromogranin B and secretoneurin were applied as soluble constituents for large dense core vesicles, synaptophysin as a vesicle membrane marker and calbindin as a cytosolic protein. In controls, chromogranin B and secretogranin are largely co-contained in interneurons, whereas chromogranin A is mostly found in pyramidal neurons. In Alzheimer's disease, about 30% of beta-amyloid plaques co-labelled with chromogranin A, 20% with secretoneurin and 15% with chromogranin B. Less than 5% of beta-amyloid plaques contained synaptophysin or calbindin, respectively. Semiquantitative immunohistochemistry revealed a significant loss for chromogranin B- and secretoneurin-like immunoreactivity in the dorsolateral, the entorhinal, and orbitofrontal cortex. Chromogranin A displayed more complex changes. It was the only chromogranin peptide to be expressed in glial fibrillary acidic protein containing cells. About 40% of chromogranin A immunopositive plaques and extracellular deposits were surrounded and pervaded by activated microglia. The present study demonstrates a loss of presynaptic proteins involved in distinct steps of exocytosis. An imbalanced availability of chromogranins may be responsible for impaired neurotransmission and a reduced functioning of dense core vesicles. Chromogranin A is likely to be a mediator between neuronal, glial and inflammatory mechanisms found in Alzheimer disease.
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Affiliation(s)
- Theresa Lechner
- Department of Psychiatry, Anichstrasse 35, Innsbruck A-6020, Austria
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Kaufmann WA, Humpel C, Alheid GF, Marksteiner J. Compartmentation of alpha 1 and alpha 2 GABA(A) receptor subunits within rat extended amygdala: implications for benzodiazepine action. Brain Res 2003; 964:91-9. [PMID: 12573516 DOI: 10.1016/s0006-8993(02)04082-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The extended amygdala, a morphological and functional entity within the basal forebrain, is a neuronal substrate for emotional states like fear and anxiety. Anxiety disorders are commonly treated by benzodiazepines that mediate their action via GABA(A) receptors. The binding properties and action of benzodiazepines depend on the alpha-subunit profile of the hetero-pentameric receptors: whereas the alpha1 subunit is associated with benzodiazepine type I pharmacology and reportedly mediates sedative as well as amnesic actions of benzodiazepines, the alpha2 subunit confers benzodiazepine type II pharmacology and mediates the anxiolytic actions of benzodiazepines. We determined the localization of alpha1 and alpha2 subunits within the extended amygdala, identified by secretoneurin immunostaining, to define the morphological substrates for the diverse benzodiazepine actions. A moderate expression of the alpha1 subunit could be detected in compartments of the medial subdivision and a strong expression of the alpha2 subunit throughout the central subdivision. It is concluded that the alpha1 and alpha2 subunits are differentially expressed within the extended amygdala, indicating that this structure is compartmentalized with respect to function and benzodiazepine action.
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Affiliation(s)
- Walter A Kaufmann
- Centre for Molecular Biology and Neuroscience, Department of Anatomy, University of Oslo, N-0317 Oslo, Norway
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Obermair GJ, Kaufmann WA, Knaus HG, Flucher BE. The small conductance Ca2+-activated K+ channel SK3 is localized in nerve terminals of excitatory synapses of cultured mouse hippocampal neurons. Eur J Neurosci 2003; 17:721-31. [PMID: 12603262 DOI: 10.1046/j.1460-9568.2003.02488.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [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: 12/30/2022]
Abstract
In the central nervous system small conductance Ca2+-activated K+ (SK) channels are important for generating the medium/slow afterhyperpolarization seen after single or trains of action potentials. Three SK channel isoforms (SK1,-2,-3) are differentially distributed throughout the brain, but little is known about their specific expression in particular neuronal compartments. In the hippocampus SK3 was found in the neuropil, predominantly in the terminal field of the mossy fibres and in fine varicose fibres, but excluded from the pyramidal and granule cell layers. Because this expression pattern suggested a presynaptic localization, we examined the subcellular distribution of SK3 in cultured hippocampal neurons using high-resolution immunofluorescence analysis. SK3 was localized in a punctate, synaptic pattern. The SK3 clusters were precisely colocalized with the presynaptic marker synapsin and at close range (0.4-0.5 microm) from NMDA-receptors and PSD-95. This arrangement is consistent with a localization of SK3 in the presynaptic nerve terminal, but not restricted to the synaptic membrane proper. In agreement with the increasing expression of SK3 during early postnatal development in vivo, the fraction of synapses containing SK3 increased from 14% to 57% over a six-week culture period. SK3-containing synapses were equally observed on spiny, glutamatergic and smooth GABAergic neurons. In contrast to its close association with NMDA-receptors and PSD-95, SK3 was rarely associated with GABAA-receptor clusters. Thus, SK3 is a presynaptic channel in excitatory hippocampal synapses, with no preference for glutamatergic or GABAergic postsynaptic neurons, and is probably involved in regulating neurotransmitter release.
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Affiliation(s)
- Gerald J Obermair
- Department of Physiology, University of Innsbruck, 6020 Innsbruck, Austria
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Sailer CA, Hu H, Kaufmann WA, Trieb M, Schwarzer C, Storm JF, Knaus HG. Regional differences in distribution and functional expression of small-conductance Ca2+-activated K+ channels in rat brain. J Neurosci 2002; 22:9698-707. [PMID: 12427825 PMCID: PMC6757844] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023] Open
Abstract
Small-conductance Ca2+-activated K+ (SK) channels are important for excitability control and afterhyperpolarizations in vertebrate neurons and have been implicated in regulation of the functional state of the forebrain. We have examined the distribution, functional expression, and subunit composition of SK channels in rat brain. Immunoprecipitation detected solely homotetrameric SK2 and SK3 channels in native tissue and their constitutive association with calmodulin. Immunohistochemistry revealed a restricted distribution of SK1 and SK2 protein with highest densities in subregions of the hippocampus and neocortex. In contrast, SK3 protein was distributed more diffusely in these brain regions and predominantly expressed in phylogenetically older brain regions. Whole-cell recording showed a sharp segregation of apamin-sensitive SK current within the hippocampal formation, in agreement with the SK2 distribution, suggesting that SK2 homotetramers underlie the apamin-sensitive medium afterhyperpolarizations in rat hippocampus.
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Affiliation(s)
- Claudia A Sailer
- Institute for Biochemical Pharmacology, University Innsbruck, A-6020 Innsbruck, Austria
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Nowakowski C, Kaufmann WA, Adlassnig C, Maier H, Salimi K, Jellinger KA, Marksteiner J. Reduction of chromogranin B-like immunoreactivity in distinct subregions of the hippocampus from individuals with schizophrenia. Schizophr Res 2002; 58:43-53. [PMID: 12363389 DOI: 10.1016/s0920-9964(01)00389-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Synaptic disturbances may play a key role in the pathophysiology of schizophrenia. This study was designed to further investigate possible synaptic alterations in the brains of chronic schizophrenic patients. Chromogranin B was applied as a marker for large dense core vesicles and synapsin I as a protein associated with the synaptic vesicle membrane. The distribution and density of chromogranin B-and synapsin I-like immunoreactivity in subregions of the hippocampus was compared between controls (n = 16) and patients with schizophrenia (n = 17). The overall distribution of hippocampal chromogranin B- and synapsin I-like immunoreactivity was similar in controls and in schizophrenic patients with the highest densities in the terminal field of mossy fibers and in the inner molecular layer of the dentate gyrus. In schizophrenic hippocampi, a significant reduction in the density of chromogranin B-like immunoreactivity was found in the CA4 and CA3 but not in the CA1 area of the dentate gyrus based on computerized image analysis. The loss of immunoreactivity was localized to mossy fibers and terminals surrounding hilar interneurons. Double-labelling immunohistochemistry revealed that synapsin I was co-expressed with chromogranin B in these neuronal structures and was also significantly reduced in schizophrenic hippocampi. The present study demonstrates an area-specific reduction of chromogranin B which is paralleled by a decrease of synapsin I. The loss of presynaptic proteins involved in distinct steps of exocytosis may cause complex synaptic disturbances in specific hippocampal subregions resulting in an imbalanced neurotransmitter availability in schizophrenic patients.
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Affiliation(s)
- Clara Nowakowski
- Department of Psychiatry, University of Innsbruck, Anichstrasse 35, 6020 Innsbruck, Austria
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Weis C, Kaufmann WA, Humpel C. Lipid-mediated in vivo gene transfer replaces the loss of choline acetyltransferase activity after unilateral fimbria-fornix aspiration. Cell Transplant 2002; 10:681-8. [PMID: 11814110] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
In Alzheimer's disease cholinergic neurons degenerate, resulting in loss of hippocampal acetylcholine. The fimbria-fornix aspiration is a well-known animal model mimicking hippocampal cholinergic deficiency. The aim of the present study was to use in vivo lipid-mediated gene transfer to introduce an expression vector coding for the acetylcholine synthesizing enzyme choline acetyltransferase into the hippocampus to replace the loss of enzyme activity after unilateral fimbria-fornix aspiration. Our data show that the lipid FuGene is useful to transfer DNA in vitro into 3T3 fibroblasts, C6 glioma cells, and primary astroglia and to express the respective enzyme. Lipid-mediated gene transfer in vivo resulted in a marked but transient expression of green fluorescent protein below the injection site peaking 5 days after the injection. Unilateral fimbria-fornix aspiration led to a marked reduction in the activity of choline acetyltransferase in the hippocampus, which was completely replaced 5 days after lipid-mediated gene transfer of the choline acetyltransferase vector. In conclusion, our data provide evidence that lipid-mediated gene transfer using FuGene is a useful tool to replace loss of choline acetyltranseferase activity in the hippocampus after fimbria-fornix aspiration; however, the lack of good gene transfer efficiency and the transient nature of expression limit its use for clinical applications.
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Affiliation(s)
- C Weis
- Laboratory of Psychiatry, Clinic of Psychiatry, University Hospital Innsbruck, Austria
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Pragl B, Koschak A, Trieb M, Obermair G, Kaufmann WA, Gerster U, Blanc E, Hahn C, Prinz H, Schütz G, Darbon H, Gruber HJ, Knaus HG. Synthesis, characterization, and application of cy-dye- and alexa-dye-labeled hongotoxin(1) analogues. The first high affinity fluorescence probes for voltage-gated K+ channels. Bioconjug Chem 2002; 13:416-25. [PMID: 12009929 DOI: 10.1021/bc015543s] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [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: 11/30/2022]
Abstract
Hongotoxin(1) (HgTX(1)), a 39-residue peptide recently isolated from the venom of Centruroides limbatus, blocks the voltage-gated K+ channels K(v)1.1, K(v)1.2, and K(v)1.3 at picomolar toxin concentrations (Koschak, A., Bugianesi, R. M., Mitterdorfer, J., Kaczorowski, G. J., Garcia, M. L., and Knaus, H. G. (1998) J. Biol. Chem. 273, 2639-2644). In this report, we determine the three-dimensional structure of HgTX(1) using NMR spectroscopy (PDB-code: 1HLY). HgTX(1) was found to possess a structure similar to previously characterized K+ channel toxins (e.g. margatoxin) consisting of a three-stranded antiparallel beta-sheet (residues 2-4, 26-30, and 33-37) and a helical conformation (part 3(10) helix and part alpha helix; residues 10-20). Due to the importance of residue Lys-28 for high-affinity interaction with the respective channels, lysine-reactive fluorescence dyes cannot be used to label wild-type HgTX(1). On the basis of previous studies (see above) and our NMR data, a HgTX(1) mutant (HgTX(1)-A19C) was engineered, expressed, and purified. HgTX(1)-A19C-SH was labeled using sulfhydryl-reactive Cy3-, Cy5-, and Alexa-dyes. Pharmacological characterization of fluorescently labeled HgTX(1)-A19C in radioligand binding studies indicated that these hongotoxin(1) analogues retain high-affinity for voltage-gated K+ channels and a respective pharmacological profile. Cy3- and Alexa-dye-labeled hongotoxin(1) analogues were used to investigate the localization of K+ channels in brain sections. The distribution of toxin binding closely follows the distribution of K(v)1.2 immunoreactivity with the highest expression levels in the cerebellar Purkinje cell layer. Taken together, these results demonstrate that fluorescently labeled HgTX(1) analogues comprise novel probes to characterize a subset of voltage-gated K+ channels.
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Affiliation(s)
- Bernt Pragl
- Institut für Biochemische Pharmakologie, Universität Innsbruck, Peter Mayr-Strasse 1, A-6020, Austria
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Abstract
Chromogranin A, chromogranin B, and secretogranin II are acidic proteins which are stored in large dense core vesicles of neurons. An antiserum, raised against a synthetic peptide (PE-11), present in the chromogranin B molecule, and an antiserum raised against secretoneurin contained in the secretogranin II sequence, was used to localize these peptides together with chromogranin A in the human hippocampal formation. The distribution of these peptides was investigated in Alzheimer's disease and compared to control subjects. Chromogranin A, chromogranin B, and secretogranin II are distinctly distributed with an overlap in their distribution patterns. They were only detected in neuronal structures. The highest density of immunoreactivity was found for chromogranin B. A layer specific distribution was especially obvious in the inner molecular layer of the dentate gyrus as secretoneurin-like immunoreactivity was restricted to its innermost part whereas that of chromogranin B was highly concentrated throughout the inner molecular layer. In Alzheimer's disease, about 10 to 20% of the amyloid-immunoreactive plaques contained either chromogranin A, chromogranin B or secretoneurin. The density of secretoneurin-and chromogranin B-like immunoreactivity was significantly reduced in the inner molecular layer of the dentate gyyrs, the CA1 area, the subiculum and in layers I, III and V of the entorhinal cortex. The present study demonstrates that chromogranin peptides are markers for human hippocampal pathways. Thee are particularly suitable to study nerve fibers, terminating at the inner molecular layer of the dentate gyrus. Chromogranin peptides have a potential as neuronal markers for synaptic degeneration in Alzheimer's disease.
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Affiliation(s)
- Josef Marksteiner
- Institute for Biochemical Pharmacology, Department of Psychiatry, University Innsbruck, Austria.
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Embacher N, Kaufmann WA, Beer R, Maier H, Jellinger KA, Poewe W, Ransmayr G. Apoptosis signals in sporadic amyotrophic lateral sclerosis: an immunocytochemical study. Acta Neuropathol 2001; 102:426-34. [PMID: 11699554 DOI: 10.1007/s004010100438] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [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: 10/25/2022]
Abstract
Sporadic amyotrophic lateral sclerosis (sALS) is a neurodegenerative disorder of unknown cause characterized by selective loss of both upper and lower motor neurons. Whether neuronal death in sALS is due to apoptosis has so far not been clarified. In this study, the expression and distribution patterns of pro- and anti-apoptotic bcl-2 family members as well as the executioner caspase-3 were investigated in post-mortem CNS tissue of eight sALS patients and seven age-matched controls. Sparse motor neurons were immunoreactive for bcl-2, bax, bak, and CM1 on serial sections through the spinal cord and motor cortex of individual sALS patients and controls. However, there was no obvious difference in the numbers of immunoreactive (IR) neurons between the two groups. The study did not find evidence for apoptosis as a major mechanism of motor neuronal cell death in sALS.
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Affiliation(s)
- N Embacher
- Department of Neurology, University Hospital Innsbruck, Austria
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Bond CT, Sprengel R, Bissonnette JM, Kaufmann WA, Pribnow D, Neelands T, Storck T, Baetscher M, Jerecic J, Maylie J, Knaus HG, Seeburg PH, Adelman JP. Respiration and parturition affected by conditional overexpression of the Ca2+-activated K+ channel subunit, SK3. Science 2000; 289:1942-6. [PMID: 10988076 DOI: 10.1126/science.289.5486.1942] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In excitable cells, small-conductance Ca2+-activated potassium channels (SK channels) are responsible for the slow after-hyperpolarization that often follows an action potential. Three SK channel subunits have been molecularly characterized. The SK3 gene was targeted by homologous recombination for the insertion of a gene switch that permitted experimental regulation of SK3 expression while retaining normal SK3 promoter function. An absence of SK3 did not present overt phenotypic consequences. However, SK3 overexpression induced abnormal respiratory responses to hypoxia and compromised parturition. Both conditions were corrected by silencing the gene. The results implicate SK3 channels as potential therapeutic targets for disorders such as sleep apnea or sudden infant death syndrome and for regulating uterine contractions during labor.
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Affiliation(s)
- C T Bond
- Vollum Institute, Department of Obstetrics and Gynecology, Oregon Health Sciences University, Portland, OR 97201, USA
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Marksteiner J, Lechner T, Kaufmann WA, Gurka P, Humpel C, Nowakowski C, Maier H, Jellinger KA. Distribution of chromogranin B-like immunoreactivity in the human hippocampus and its changes in Alzheimer's disease. Acta Neuropathol 2000; 100:205-12. [PMID: 10963369 DOI: 10.1007/s004010000239] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [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: 11/25/2022]
Abstract
Synapse loss is crucially involved in cognitive decline in Alzheimer's disease (AD). This study was performed to investigate the distribution and density of chromogranin B-like immunoreactivity in the hippocampus of control compared to AD brain. Chromogranin B is a large precursor molecule found in large dense-core vesicles. For immunocytochemistry we used an antiserum raised against a synthetic peptide (PE- 11) present in the chromogranin B molecule. Chromogranin B-like immunoreactivity was concentrated in the terminal field of mossy fibers, the inner molecular layer of the dentate gyrus and in layer II of the entorhinal cortex. In AD, chromogranin B was detected in neuritic plaques. The density of chromogranin B-like immunoreactivity was significantly reduced in the inner molecular layer of the dentate gyrus and in layers II, III and V of the entorhinal cortex in AD brains. The present study demonstrates that chromogranin B is a marker for human hippocampal pathways. It is particularly suitable for studying nerve fibers terminating at the inner molecular layer of the dentate gyrus. It is present in neuritic plaques, and its density is reduced in a layer-specific manner.
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Affiliation(s)
- J Marksteiner
- Department of Psychiatry, University of Innsbruck, Austria.
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38
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Abstract
3,4-Methylenedioxymetamphetamine (MDMA, "ecstasy") is an increasingly abused drug, which has significant effects on the dopamine system in the striatum. The isolated single organotypic slice model allows investigation of the effects of drugs of abuse on the expression of transcription factors in the striatum without dopaminergic and glutamatergic interactions. In this study the effects of MDMA on the expression of c-fos mRNA by in situ hybridization as well as the c-fos-like protein by immunohistochemistry in isolated dorsal striatum was investigated. It was shown that 100 microM MDMA induced c-fos mRNA expression 30 min after treatment. Expression of c-fos-like protein was transiently detected 3 h afterwards. The c-fos expression was inhibited by MK 801 and metoclopramide, indicating the involvement of dopaminergic D2 receptors and glutamatergic NMDA receptors. The dopaminergic D1 receptor antagonist SCH 23390 did not affect c-fos expression. We conclude that MDMA treatment leads to the induction of c-fos expression in isolated rat striatal slices. This effect is independent of extrinsic neuronal circuitry and seems to be associated with direct interactions between MDMA and the dopamine/glutamate receptor system.
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Affiliation(s)
- D S Schatz
- Division of Neurochemistry, Department of Psychiatry, University Hospital Innsbruck, Austria
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39
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Abstract
Gene therapy is a potent method to counteract neurodegeneration by introducing genetic information encoding neuroprotective factors. In this study cationic lipids were used to transfer DNA into C6 glioma cells and primary glial cells. When comparing the novel compound FuGene with other commercially-available lipids, it was found that FuGene markedly enhanced gene transfer of a beta-galactosidase reporter plasmid into C6 glioma cells. FuGene had several advantages compared to other lipids, such as a very low toxicity and the capability of transfection under serum conditions. When optimizing, a DNA-lipid ratio of 150 ng DNA/1 microl FuGene and a concentration of 3 microl FuGene/1 ml medium was found to be optimal. The incubation time peaked after 8 h and the expression time reached an optimum between 2 and 6 days. When cells were transfected on 3 consecutive days for 6 h each ('boosting'), the transfection efficiency was markedly enhanced in primary glial cells. When using endotoxin-free DNA the transfection efficiency could be enhanced up to 3 times. The optimal transfection efficiency in C6 glioma cells and in primary glial cells was found to be 16.3 +/- 0.3% and 5.1 +/- 0.37% of total cells, respectively. In conclusion this study shows that the novel compound FuGene has a very high potential to transfer DNA into cells of glial origin, and it might be an interesting canditate for ex vivo and in vivo gene therapeutic approaches.
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Affiliation(s)
- B Wiesenhofer
- Department of Psychiatry, University Hospital Innsbruck, Austria
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40
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Abstract
Neurodegeneration of dopamine neurons in the ventral mesencephalon projecting to the dorsal striatum (meso-striatal system) plays a major role in Parkinson's disease. The aim of this study was to establish a simple organotypic, in vitro co-culture model for investigating the survival of dopamine neurons stimulated by the novel growth factor, glial-cell-line-derived neurotrophic factor. This model should allow investigation of the effects of the dopaminergic neurotoxin, 6-hydroxydopamine, on the expression of the transcription factor c-fos and on TUNEL staining in vitro. The dopaminotrophic factor, glial-cell-line-derived neurotrophic factor, markedly enhanced dopamine tissue levels and dopamine neuron number. Nerve-fiber ingrowth of dopamine neurons into its striatal target was found to be enhanced with glial-cell-line-derived neurotrophic factor. Using an optimized protocol, it was shown that the neurotoxin 6-hydroxydopamine selectively destructed dopamine neurons. C-fos-like immunoreactivity was enhanced in the mesencephalic part of the co-slices 3 h after application of the neurotoxin. The TUNEL staining occurred 2-5 days after the application of the neurotoxin, but did not seem to be related to dopamine neurons. In conclusion, the organotypic co-culture model provides a simple model for studying survival of dopamine neurons and for observing expression of genes and proteins that could be related to Parkinson's disease. This simple model is useful for screening novel drugs and growth factors and may markedly reduce severe animal experiments.
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Affiliation(s)
- D S Schatz
- Department of Psychiatry, University Hospital, Innsbruck, Austria
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41
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Abstract
This study was performed to investigate the distribution of chromogranin B in the human central nervous system. We used an antiserum raised against a synthetic peptide (PE-11) present in the chromogranin B molecule. PE-11-like immunoreactivity was characterized by molecular size exclusion and reversed-phase high-performance liquid chromatography. Its localization was studied using immunocytochemistry. Only the free peptide and an N-terminally elongated peptide were detected by molecular size exclusion high-performance liquid chromatography, indicating that proteolytic processing of chromogranin B is quite extensive. PE-11-like immunoreactivity was present in differently shaped fibers, varicosities and neurons, but not in glial cells. Its density varied throughout the brain. An especially high density was observed in the bed nucleus of the stria terminalis, the central and cortical nuclei of the amygdala, the hypothalamus, the hippocampus, the raphe complex, the nucleus interpeduncularis, the nucleus of the solitary tract, and laminae I and II of the spinal cord. This study demonstrates a significant processing of chromogranin B and indicates that chromogranin B constitutes a precursor for smaller peptides which are derived by endoproteolytic processing. It provides the neuroanatomical basis to investigate the chromogranin B molecule as a widespread component of large dense-core vesicles in the human central nervous system.
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Kaufmann WA, Barnas U, Humpel C, Nowakowski K, DeCol C, Gurka P, Ransmayr G, Hinterhuber H, Winkler H, Marksteiner J. Synaptic loss reflected by secretoneurin-like immunoreactivity in the human hippocampus in Alzheimer's disease. Eur J Neurosci 1998; 10:1084-94. [PMID: 9753176 DOI: 10.1046/j.1460-9568.1998.00121.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [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: 11/20/2022]
Abstract
Secretoneurin is a recently described peptide derived by endoproteolytic processing from secretogranin II, previously named chromogranin C. In this study, we have investigated the distribution of secretoneurin-like immunoreactivity in the human hippocampus in controls and in Alzheimer's disease patients, and compared the staining pattern to that of calretinin. Secretoneurin-like immunoreactivity is present throughout the hippocampal formation. At the border of the dentate molecular layer and the granule cell layer, a band of dense secretoneurin immunostaining appeared. In this part, as in the area of the CA2 sector, the high density of secretoneurin-immunoreactivity coincided with calretinin-like immunoreactivity. The mossy fibre system displayed a moderate density of secretoneurin-immunoreactivity. In the entorhinal cortex, a particularly high density of secretoneurin-immunoreactivity was observed. The density of secretoneurin-like immunoreactivity was significantly reduced in the innermost part of the molecular layer and in the outer molecular layer of the dentate gyrus in Alzheimer's disease. For calretinin-like immunoreactivity, a less pronounced decrease was found in the innermost part of the molecular layer. About 40-60% of neuritic plaques were secretoneurin-immunopositive. This study shows that secretoneurin is distinctly distributed in the human hippocampus and that significant changes of secretoneurin-like immunoreactivity occur in Alzheimer's disease, reflecting synaptic loss.
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Leitner B, Kaufmann WA, Marksteiner J, Hoflehner J, Traurig H, Saria A, Fischer-Colbrie R, Winkler H. Ontogenic development of secretogranin II and of its processing to secretoneurin in rat brain. Brain Res Dev Brain Res 1997; 100:161-8. [PMID: 9205807 DOI: 10.1016/s0165-3806(97)00042-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The ontogenic development of secretogranin II was studied by immunochemistry and immunohistochemistry. Extracts of brains from various developmental stages were analyzed by a radioimmunoassay for secretoneurin, a peptide derived from secretogranin II. From gestational day 13 to adulthood the levels increased from 0.1 to 94 fmol/mg wet weight. Characterization of the immunoreactivity by molecular sieve chromatography revealed that throughout all developmental stages the proprotein secretogranin II was fully processed to the free peptide secretoneurin. In immunohistochemistry secretoneurin-IR was first detected at embryonic day 13. Between embryonic days 14 and 18 a strong increase in the number of secretoneurin immunopositive cells was observed in many brain areas, notably in the amygdala, hypothalamus, olfactory bulb and several brainstem nuclei. The pattern of staining during development is quite similar to that in the adult. The present paper demonstrates that secretoneurin immunoreactivity appears early in embryonic life. Processing of the proprotein secretogranin II starts when the protein is first synthesized apparently at about the same time when the prohormone convertase PC1 and PC2 can be demonstrated.
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Affiliation(s)
- B Leitner
- Department of Pharmacology, University of Innsbruck, Austria
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Kaufmann WA, Barnas U, Maier J, Saria A, Alheid GF, Marksteiner J. Neurochemical compartments in the human forebrain: evidence for a high density of secretoneurin-like immunoreactivity in the extended amygdala. Synapse 1997; 26:114-30. [PMID: 9131771 DOI: 10.1002/(sici)1098-2396(199706)26:2<114::aid-syn3>3.0.co;2-b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Secretoneurin is a 33-amino acid neuropeptide produced by endoproteolytic processing from secretogranin II, which is a member of the chromogranin/ secretogranin family. In this immunocytochemical study we investigated the localization of secretoneurin-like immunoreactivity in the human substantia innominata in relation to the ventral striatopallidal system, the bed nucleus-amygdala complex and the basal nucleus of Meynert. A high density of secretoneurin immunostaining was found in the medial part of the nucleus accumbens. All subdivisions of the bed nucleus of the stria terminalis displayed a very prominent immunostaining for secretoneurin, whereas substance P and enkephalin showed a more restricted distribution. A high concentration of secretoneurin immunoreactivity was also observed in the central and medial amygdaloid nuclei. In the lateral bed nucleus of the stria terminalis and the sublenticular substantia innominata, the appearance of secretoneurin immunoreactivity was very similar to that of enkephalin-like immunoreactivity, exhibiting mostly peridendritic and perisomatic staining. The ventral pallidum and the inner pallidal segment displayed strong secretoneurin immunostaining. Secretoneurin did not label cholinergic neurons in the basal forebrain. This study demonstrates that secretoneurin-like immunoreactivity is prominent in the bed nucleus-amygdala complex, referred to as extended amygdala. The distribution of secretoneurin-like immunoreactivity in comparison with that of other neuroanatomical markers suggests that this forebrain system is a discret compartment in the human forebrain.
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Affiliation(s)
- W A Kaufmann
- Clinic of Psychiatry, University of Innsbruck, Austria
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45
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Saria A, Kaufmann WA, Marksteiner J, Leitner B, Traurig H, Fischer-Colbrie R, Winkler H. Distribution and processing of secretoneurin in the developing rat brain. Ann N Y Acad Sci 1997; 814:90-6. [PMID: 9160962 DOI: 10.1111/j.1749-6632.1997.tb46148.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- A Saria
- Department of Psychiatry, University Hospital, Innsbruck, Austria.
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