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Ceder MM, Weman HM, Johansson E, Henriksson K, Magnusson KA, Roman E, Lagerström MC. The glycine receptor alpha 3 subunit mRNA expression shows sex-dependent differences in the adult mouse brain. BMC Neurosci 2023; 24:32. [PMID: 37264306 DOI: 10.1186/s12868-023-00800-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/28/2023] [Indexed: 06/03/2023] Open
Abstract
BACKGROUND The glycinergic system plays an important inhibitory role in the mouse central nervous system, where glycine controls the excitability of spinal itch- and pain-mediating neurons. Impairments of the glycine receptors can cause motor and sensory deficits. Glycine exerts inhibition through interaction with ligand-gated ion channels composed of alpha and beta subunits. We have investigated the mRNA expression of the glycine receptor alpha 3 (Glra3) subunit in the nervous system as well as in several peripheral organs of female and male mice. RESULTS Single-cell RNA sequencing (scRNA-seq) data analysis on the Zeisel et al. (2018) dataset indicated widespread but low expression of Glra3 in vesicular glutamate transporter 2 (Vglut2, Slc17a6) positive and vesicular inhibitory amino acid transporter (Viaat, Slc32a1)positive neurons of the mouse central nervous system. Highest occurrence of Glra3 expression was identified in the cortex, amygdala, and striatal regions, as well as in the hypothalamus, brainstem and spinal cord. Bulk quantitative real-time-PCR (qRT-PCR) analysis demonstrated Glra3 expression in cortex, amygdala, striatum, hypothalamus, thalamus, pituitary gland, hippocampus, cerebellum, brainstem, and spinal cord. Additionally, male mice expressed higher levels of Glra3 in all investigated brain areas compared with female mice. Lastly, RNAscope spatially validated Glra3 expression in the areas indicated by the single-cell and bulk analyses. Moreover, RNAscope analysis confirmed co-localization of Glra3 with Slc17a6 or Slc32a1 in the central nervous system areas suggested from the single-cell data. CONCLUSIONS Glra3 expression is low but widespread in the mouse central nervous system. Clear sex-dependent differences have been identified, indicating higher levels of Glra3 in several telencephalic and diencephalic areas, as well as in cerebellum and brainstem, in male mice compared with female mice.
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Affiliation(s)
- Mikaela M Ceder
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Hannah M Weman
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Ebba Johansson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Katharina Henriksson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Kajsa A Magnusson
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Erika Roman
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Neuropharmacology and Addiction, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden
| | - Malin C Lagerström
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
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2
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Fricke S, Harnau M, Hetsch F, Liu H, Leonhard J, Eylmann A, Knauff P, Sun H, Semtner M, Meier JC. Cesium activates the neurotransmitter receptor for glycine. Front Mol Neurosci 2023; 16:1018530. [PMID: 37284465 PMCID: PMC10239821 DOI: 10.3389/fnmol.2023.1018530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 05/02/2023] [Indexed: 06/08/2023] Open
Abstract
The monovalent cations sodium and potassium are crucial for the proper functioning of excitable cells, but, in addition, other monovalent alkali metal ions such as cesium and lithium can also affect neuronal physiology. For instance, there have been recent reports of adverse effects resulting from self-administered high concentrations of cesium in disease conditions, prompting the Food and Drug Administration (FDA) to issue an alert concerning cesium chloride. As we recently found that the monovalent cation NH4+ activates glycine receptors (GlyRs), we investigated the effects of alkali metal ions on the function of the GlyR, which belongs to one of the most widely distributed neurotransmitter receptors in the peripheral and central nervous systems. Whole-cell voltage clamp electrophysiology was performed with HEK293T cells transiently expressing different splice and RNA-edited variants of GlyR α2 and α3 homopentameric channels. By examining the influence of various milli- and sub-millimolar concentrations of lithium, sodium, potassium, and cesium on these GlyRs in comparison to its natural ligand glycine (0.1 mM), we could show that cesium activates GlyRs in a concentration- and post-transcriptional-dependent way. Additionally, we conducted atomistic molecular dynamic simulations on GlyR α3 embedded in a membrane bilayer with potassium and cesium, respectively. The simulations revealed slightly different GlyR-ion binding profiles for potassium and cesium, identifying interactions near the glycine binding pocket (potassium and cesium) and close to the RNA-edited site (cesium) in the extracellular GlyR domain. Together, these findings show that cesium acts as an agonist of GlyRs.
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Affiliation(s)
- Steffen Fricke
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Magnus Harnau
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Florian Hetsch
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Haoran Liu
- Structural Chemistry and Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
- Institute of Chemistry, Technical University of Berlin, Berlin, Germany
| | - Julia Leonhard
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Anna Eylmann
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Pina Knauff
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Han Sun
- Structural Chemistry and Computational Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
- Institute of Chemistry, Technical University of Berlin, Berlin, Germany
| | - Marcus Semtner
- Psychoneuroimmunology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jochen C. Meier
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
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Kuhse J, Groeneweg F, Kins S, Gorgas K, Nawrotzki R, Kirsch J, Kiss E. Loss of Extrasynaptic Inhibitory Glycine Receptors in the Hippocampus of an AD Mouse Model Is Restored by Treatment with Artesunate. Int J Mol Sci 2023; 24:ijms24054623. [PMID: 36902054 PMCID: PMC10002537 DOI: 10.3390/ijms24054623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/14/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by synaptic failure and neuronal loss. Recently, we demonstrated that artemisinins restored the levels of key proteins of inhibitory GABAergic synapses in the hippocampus of APP/PS1 mice, a model of cerebral amyloidosis. In the present study, we analyzed the protein levels and subcellular localization of α2 and α3 subunits of GlyRs, indicated as the most abundant receptor subtypes in the mature hippocampus, in early and late stages of AD pathogenesis, and upon treatment with two different doses of artesunate (ARS). Immunofluorescence microscopy and Western blot analysis demonstrated that the protein levels of both α2 and α3 GlyRs are considerably reduced in the CA1 and the dentate gyrus of 12-month-old APP/PS1 mice when compared to WT mice. Notably, treatment with low-dose ARS affected GlyR expression in a subunit-specific way; the protein levels of α3 GlyR subunits were rescued to about WT levels, whereas that of α2 GlyRs were not affected significantly. Moreover, double labeling with a presynaptic marker indicated that the changes in GlyR α3 expression levels primarily involve extracellular GlyRs. Correspondingly, low concentrations of artesunate (≤1 µM) also increased the extrasynaptic GlyR cluster density in hAPPswe-transfected primary hippocampal neurons, whereas the number of GlyR clusters overlapping presynaptic VIAAT immunoreactivities remained unchanged. Thus, here we provide evidence that the protein levels and subcellular localization of α2 and α3 subunits of GlyRs show regional and temporal alterations in the hippocampus of APP/PS1 mice that can be modulated by the application of artesunate.
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Affiliation(s)
- Jochen Kuhse
- Institute of Anatomy and Cell Biology, University of Heidelberg, 69117 Heidelberg, Germany
| | - Femke Groeneweg
- Institute of Anatomy and Cell Biology, University of Heidelberg, 69117 Heidelberg, Germany
- Institute of Neuroanatomy, Medical Faculty Mannheim, University Heidelberg, 68167 Mannheim, Germany
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern-Landau, 67663 Kaiserslautern, Germany
| | - Karin Gorgas
- Institute of Anatomy and Cell Biology, University of Heidelberg, 69117 Heidelberg, Germany
| | - Ralph Nawrotzki
- Institute of Anatomy and Cell Biology, University of Heidelberg, 69117 Heidelberg, Germany
| | - Joachim Kirsch
- Institute of Anatomy and Cell Biology, University of Heidelberg, 69117 Heidelberg, Germany
| | - Eva Kiss
- Institute of Anatomy and Cell Biology, University of Heidelberg, 69117 Heidelberg, Germany
- Department of Cellular and Molecular Biology, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Târgu Mureș, 540142 Târgu Mures, Romania
- Correspondence:
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Bhumika S, Basalingappa KM, Gopenath TS, Basavaraju S. Glycine encephalopathy. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2022; 58:132. [PMCID: PMC9672649 DOI: 10.1186/s41983-022-00567-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/19/2022] [Indexed: 11/18/2022] Open
Abstract
Inherited neurotransmitter diseases are a subset of rare neurometabolic disorders characterized by hereditary deficiencies in neurotransmitter metabolism or transport. Non-ketotic hyperglycinaemia (NKH), called glycine encephalopathy, is an autosomal recessive glycine metabolism disorder characterized by an abnormal accumulation of glycine in all bodily tissues, including the CNS. The SLC6A9 gene, which codes for the GLYT1 protein, a biochemical abnormality in the GCS, and dihydrolipoamide dehydrogenase enzymes, which function as a GCS component, are responsible for the neonatal form’s symptoms, which include progressive encephalopathy, hypotonia, seizures, and occasionally mortality in the first few days of life. By changing the MAPK signalling pathways, glycine deprivation in the brain damages neurons by increasing NMDA receptor activation, increasing intracellular Ca levels, and leading to DNA breakage and cell death in the neuron region. In addition to the previously mentioned clinical diagnosis, NKH or GE would be determined by MLPA and 13C glycine breath tests. Pediatricians, surgeons, neurologists, and geneticists treat NKH and GE at the newborn period; there is no cure for either condition.
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Hetero-pentamerization determines mobility and conductance of Glycine receptor α3 splice variants. Cell Mol Life Sci 2022; 79:540. [PMID: 36197517 PMCID: PMC9534812 DOI: 10.1007/s00018-022-04506-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/21/2022] [Accepted: 07/23/2022] [Indexed: 11/05/2022]
Abstract
Glycine receptors (GlyRs) are ligand-gated pentameric chloride channels in the central nervous system. GlyR-α3 is a possible target for chronic pain treatment and temporal lobe epilepsy. Alternative splicing into K or L variants determines the subcellular fate and function of GlyR-α3, yet it remains to be shown whether its different splice variants can functionally co-assemble, and what the properties of such heteropentamers would be. Here, we subjected GlyR-α3 to a combined fluorescence microscopy and electrophysiology analysis. We employ masked Pearson’s and dual-color spatiotemporal correlation analysis to prove that GlyR-α3 splice variants heteropentamerize, adopting the mobility of the K variant. Fluorescence-based single-subunit counting experiments revealed a variable and concentration ratio dependent hetero-stoichiometry. Via cell-attached single-channel electrophysiology we show that heteropentamers exhibit currents in between those of K and L variants. Our data are compatible with a model where α3 heteropentamerization fine-tunes mobility and activity of GlyR-α3 channels, which is important to understand and tackle α3 related diseases.
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Petukhova E, Ponomareva D, Rustler K, Koenig B, Bregestovski P. Action of the Photochrome Glyght on GABAergic Synaptic Transmission in Mouse Brain Slices. Int J Mol Sci 2022; 23:ijms231810553. [PMID: 36142469 PMCID: PMC9503965 DOI: 10.3390/ijms231810553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
Glyght is a new photochromic compound described as an effective modulator of glycine receptors at heterologous expression, in brain slices and in zebrafish larvae. Glyght also caused weak inhibition of GABAA-mediated currents in a cell line expressing α1/β2/γ2 GABAA receptors. However, the effects of Glyght on GABAergic transmission in the brain have not been analysed, which does not allow a sufficiently comprehensive assessment of the effects of the compound on the nervous system. Therefore, in this study using whole-cell patch-clamp recording, we analysed the Glyght (100 µM) action on evoked GABAergic inhibitory postsynaptic currents (eIPSCs) in mice hippocampal slices. Two populations of cells were found: the first responded by reducing the GABAergic eIPSCs’ amplitude, whereas the second showed no sensitivity to the compound. Glyght did not affect the ionic currents’ amplitude induced by GABA application, suggesting the absence of action on postsynaptic GABA receptors. Additionally, Glyght had no impact on the paired-pulse modulation of GABAergic eIPSCs, indicating that Glyght does not modulate the neurotransmitter release mechanisms. In the presence of strychnine, an antagonist of glycine receptors, the Glyght effect on GABAergic synaptic transmission was absent. Our results suggest that Glyght can modulate GABAergic synaptic transmission via action on extrasynaptic glycine receptors.
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Affiliation(s)
- Elena Petukhova
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia
- OpenLab Gene and Cell Technologies, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia
| | - Daria Ponomareva
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia
- Institut de Neurosciences des Systèmes, Aix-Marseille University, INSERM, INS, 13005 Marseille, France
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
| | - Karin Rustler
- Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
| | - Burkhard Koenig
- Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
| | - Piotr Bregestovski
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia
- Institut de Neurosciences des Systèmes, Aix-Marseille University, INSERM, INS, 13005 Marseille, France
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
- Correspondence:
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7
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San Martin LS, Armijo-Weingart L, Araya A, Yévenes GE, Harvey RJ, Aguayo LG. Contribution of GlyR α3 Subunits to the Sensitivity and Effect of Ethanol in the Nucleus Accumbens. Front Mol Neurosci 2021; 14:756607. [PMID: 34744627 PMCID: PMC8570041 DOI: 10.3389/fnmol.2021.756607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
The glycine receptor (GlyR), a ligand-gated ion channel, is critical for inhibitory neurotransmission in brainstem, spinal cord, and in supraspinal regions. Recent data from several laboratories have shown that GlyRs are expressed in the brain reward circuitry and that α1 and α2 are the principal subunits expressed in the nucleus accumbens (nAc). In the present study, we studied the sensitivity to ethanol of homomeric and heteromeric α3 GlyR subunits in HEK293 cells and dissociated neurons from the nAc. Finally, we explored ethanol-related behaviors in a Glra3 knockout mouse (Glra3–/–). Studies in HEK293 cells showed that while homomeric α3 GlyR subunits were insensitive to ethanol, heteromeric α3β GlyR subunits showed higher sensitivity to ethanol. Additionally, using electrophysiological recordings in dissociated accumbal neurons, we found that the glycine current density increased in Glra3–/– mice and the GlyRs were less affected by ethanol and picrotoxin. We also examined the effect of ethanol on sedation and drinking behavior in Glra3–/– mice and found that the duration in the loss of righting reflex (LORR) was unchanged compared to wild-type (WT) mice. On the other hand, using the drinking in the dark (DID) paradigm, we found that Glra3–/– mice have a larger ethanol consumption compared to WT mice, and that this was already high during the first days of exposure to ethanol. Our results support the conclusion that heteromeric α3β, but not homomeric α3, GlyRs are potentiated by ethanol. Also, the increase in GlyR and GABAAR mediated current densities in accumbal neurons in the KO mice support the presence of compensatory changes to α3 knock out. The increase in ethanol drinking in the Glra3–/– mice might be associated to the reduction in β and compensatory changes in other subunits in the receptor arrangement.
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Affiliation(s)
- Loreto S San Martin
- Department of Physiology, Programa de Neurociencia, Psiquiatria y Salud Mental, Universidad de Concepción, Concepción, Chile
| | - Lorena Armijo-Weingart
- Department of Physiology, Programa de Neurociencia, Psiquiatria y Salud Mental, Universidad de Concepción, Concepción, Chile
| | - Anibal Araya
- Department of Physiology, Programa de Neurociencia, Psiquiatria y Salud Mental, Universidad de Concepción, Concepción, Chile
| | - Gonzalo E Yévenes
- Department of Physiology, Programa de Neurociencia, Psiquiatria y Salud Mental, Universidad de Concepción, Concepción, Chile
| | - Robert J Harvey
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sunshine Coast, QLD, Australia.,Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Luis G Aguayo
- Department of Physiology, Programa de Neurociencia, Psiquiatria y Salud Mental, Universidad de Concepción, Concepción, Chile
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8
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Rapid effects of neurosteroids on neuronal plasticity and their physiological and pathological implications. Neurosci Lett 2021; 750:135771. [PMID: 33636284 DOI: 10.1016/j.neulet.2021.135771] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/15/2021] [Accepted: 02/20/2021] [Indexed: 11/22/2022]
Abstract
Current neuroscience research on neurosteroids and their synthetic analogues - neuroactive steroids - clearly demonstrate their drug likeness in a variety of neurological and psychiatric conditions. Moreover, research on neurosteroids continues to provide novel mechanistic insights into receptor activation or inhibition of various receptors. This mini-review will provide a high-level overview of the research area and discuss the various classes of potential physiological and pathological implications discovered so far.
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9
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Hussein RA, Ahmed M, Sticht H, Breitinger HG, Breitinger U. Fine-Tuning of Neuronal Ion Channels-Mapping of Residues Involved in Glucose Sensitivity of Recombinant Human Glycine Receptors. ACS Chem Neurosci 2020; 11:3474-3483. [PMID: 33007159 DOI: 10.1021/acschemneuro.0c00566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The inhibitory glycine receptor (GlyR) mediates synaptic inhibition in the spinal cord, brain stem, and other regions of the mammalian central nervous system. Glucose was shown to potentiate α1 GlyRs by interacting with K143. Here, additional amino acids involved in glucose modulation were identified using a structure-based approach of site-directed mutagenesis followed by whole-cell patch-clamp analysis. We identified two additional lysine residues in the α1 GlyR extracellular domain, K16 and K281, that were involved in glucose modulation. Mutation of either residue to alanine abolished glucose potentiation. Residue K281 is located in the same pocket as K143 and could thus contribute to glucose binding. The double mutant K143A-K281A showed a 6-fold increase of EC50, while EC50 of both single mutants K143A and K281A was only slightly increased (1.7- and 1.3-fold, respectively). K16 is located at an analgesic binding site that is distant from the agonist or glucose sites, and the K16A mutation may generate a receptor species that is not potentiated. GlyR position α1-S267 is close to the postulated glucose binding site and known for interactions with ethanol and anesthetics. In the presence of glucose, GlyR α1 mutants S267A, S267I, and S267R showed potentiation, no effect, and reduction of current responses, respectively. This pattern follows that of ethanol modulation and suggests that the interaction sites of glucose and ethanol are identical or located close to each other. Our results support the presence of a distinct binding site for glucose on the glycine receptor, overlapping with the ivermectin/ethanol binding pocket near the transmembrane region and the TM2-3 loop.
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Affiliation(s)
- Rama Ashraf Hussein
- Department of Biochemistry, The German University in Cairo, Main Entrance of Al Tagamoa Al Khames, New Cairo 11835, Egypt
| | - Marwa Ahmed
- Department of Biochemistry, The German University in Cairo, Main Entrance of Al Tagamoa Al Khames, New Cairo 11835, Egypt
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Fahrstrasse 17, D-91054 Erlangen, Germany
| | - Hans-Georg Breitinger
- Department of Biochemistry, The German University in Cairo, Main Entrance of Al Tagamoa Al Khames, New Cairo 11835, Egypt
| | - Ulrike Breitinger
- Department of Biochemistry, The German University in Cairo, Main Entrance of Al Tagamoa Al Khames, New Cairo 11835, Egypt
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Zhang ZY, Bai HH, Guo Z, Li HL, He YT, Duan XL, Suo ZW, Yang X, He YX, Hu XD. mGluR5/ERK signaling regulated the phosphorylation and function of glycine receptor α1ins subunit in spinal dorsal horn of mice. PLoS Biol 2019; 17:e3000371. [PMID: 31433808 PMCID: PMC6703679 DOI: 10.1371/journal.pbio.3000371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 07/24/2019] [Indexed: 12/29/2022] Open
Abstract
Inhibitory glycinergic transmission in adult spinal cord is primarily mediated by glycine receptors (GlyRs) containing the α1 subunit. Here, we found that α1ins, a longer α1 variant with 8 amino acids inserted into the intracellular large loop (IL) between transmembrane (TM)3 and TM4 domains, was expressed in the dorsal horn of the spinal cord, distributed at inhibitory synapses, and engaged in negative control over nociceptive signal transduction. Activation of metabotropic glutamate receptor 5 (mGluR5) specifically suppressed α1ins-mediated glycinergic transmission and evoked pain sensitization. Extracellular signal-regulated kinase (ERK) was critical for mGluR5 to inhibit α1ins. By binding to a D-docking site created by the 8-amino–acid insert within the TM3–TM4 loop of α1ins, the active ERK catalyzed α1ins phosphorylation at Ser380, which favored α1ins ubiquitination at Lys379 and led to α1ins endocytosis. Disruption of ERK interaction with α1ins blocked Ser380 phosphorylation, potentiated glycinergic synaptic currents, and alleviated inflammatory and neuropathic pain. These data thus unraveled a novel, to our knowledge, mechanism for the activity-dependent regulation of glycinergic neurotransmission. Activity-dependent phosphorylation of the glycine receptor α1ins subunit by metabotropic glutamate receptor 5 and ERK kinase signalling causes endocytosis of α1ins and glycinergic disinhibition in the spinal cord dorsal horn, contributing to pain sensitization.
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Affiliation(s)
- Zi-Yang Zhang
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Hu-Hu Bai
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Zhen Guo
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Hu-Ling Li
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Yong-Tao He
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Xing-Lian Duan
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Zhan-Wei Suo
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Xian Yang
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
| | - Yong-Xing He
- School of Life Sciences, Lanzhou University, Lanzhou, Gansu, PR China
| | - Xiao-Dong Hu
- Department of Molecular Pharmacology, School of Pharmacy, Lanzhou University, Lanzhou, Gansu, PR China
- * E-mail:
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Principal Neurons in the Anteroventral Cochlear Nucleus Express Cell-Type Specific Glycine Receptor α Subunits. Neuroscience 2019; 415:77-88. [PMID: 31325562 DOI: 10.1016/j.neuroscience.2019.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 11/21/2022]
Abstract
Signal processing in the principal neurons of the anteroventral cochlear nucleus (AVCN) is modulated by glycinergic inhibition. The kinetics of IPSCs are specific to the target neurons. It remains unclear what glycine receptor subunits are involved in generating such target-specific IPSC kinetics in AVCN principal neurons. We investigated the expression patterns of glycine receptor α (GlyRα) subunits in AVCN using immunohistochemical labeling of four isoforms of GlyRα subunits (GlyRα1-α4), and found that AVCN neurons express GlyRα1 and GlyRα4, but not GlyRα2 and GlyRα3 subunits. To further identify the cell type-specific expression patterns of GlyRα subunits, we combined whole-cell patch clamp recording with immunohistochemistry by recording from all three types of AVCN principal neurons, characterizing the synaptic properties of their glycinergic inhibition, dye-filling the neurons, and processing the slice for immunostaining of different GlyRα subunits. We found that AVCN bushy neurons express both GlyRα1 and GlyRα4 subunits that underlie their slow IPSC kinetics, whereas both T-stellate and D-stellate neurons express only GlyRα1 subunit that underlies their fast IPSC kinetics. In conclusion, AVCN principal neurons express cell-type specific GlyRα subunits that underlie their distinct IPSC kinetics, which enables glycinergic inhibition from the same source to exert target cell-specific modulation of activity to support the unique physiological function of these neurons.
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Lushnikova I, Maleeva G, Skibo G. Glycine receptors are involved in hippocampal neuronal damage caused by oxygen-glucose deficiency. Cell Biol Int 2018; 42:1423-1431. [PMID: 30022566 DOI: 10.1002/cbin.11034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/13/2018] [Indexed: 11/07/2022]
Abstract
Glycine receptors (GlyRs) belong to the family of ligand-gated cys-loop receptors and effectuate fast inhibitory neurotransmission in central nervous system (CNS). They are involved in numerous physiological processes, such as movement, respiration, and processing of sensory information, as well as in regulation of neuronal excitability in different brain regions. GlyRs play important role in the maintenance of excitatory/inhibitory balance in the hippocampus and participate in the development of various brain pathologies. In the present study, we have examined a surface expression of GlyRs by pyramidal neurons and astrocytes in control and after 30 min of oxygen-glucose deprivation (OGD) in the organotypic culture of hippocampal slices. Our investigation has demonstrated a decrease in GlyR-positive staining associated with pyramidal neurons and relative stability of GlyRs expression at the surface of astrocytes 4 hs after OGD. These data indicate that GlyRs dysfunction may represent a significant additional factor leading to enhanced neuronal damage induced by OGD. Pharmacological modulation of GlyRs is a promising venue of research for the correction of negative consequences of oxygen-glucose deficiency.
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Affiliation(s)
- Iryna Lushnikova
- Department of Cytology, O.O.Bogomoletz Institute of Physiology, National Academy of Sciences, Kiev, Ukraine
| | - Galyna Maleeva
- Aix-Marseille University, INSERM, INS, Institut de Neurosciences des Systèmes, Marseille, France
| | - Galyna Skibo
- Department of Cytology, O.O.Bogomoletz Institute of Physiology, National Academy of Sciences, Kiev, Ukraine
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Kuenzel K, Mofrad SA, Gilbert DF. Phenotyping Cellular Viability by Functional Analysis of Ion Channels: GlyR-Targeted Screening in NT2-N Cells. Methods Mol Biol 2018; 1601:205-214. [PMID: 28470528 DOI: 10.1007/978-1-4939-6960-9_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Glycine receptor chloride channels (GlyRs) are attractive drug targets for therapeutic intervention and are also more and more recognized in the context of in vitro neurotoxicity and developmental neurotoxicity testing. Assaying the functional properties of GlyR can serve as an indicator of cellular viability and the integrity of the developing and mature central nervous system. Human pluripotent NTERA-2 (NT2) stem cells undergo neuronal differentiation upon stimulation with retinoic acid and express a large variety of neuronal proteins-including GlyR. YFP-I152L, a halide-sensitive variant of yellow fluorescent protein, allows high-throughput fluorescence-based functional analysis of GlyRs in NT2 cells. Here we describe a protocol for phenotyping of cellular viability by functional analysis of GlyR in neuronally differentiated NT2 (NT2-N) cells using YFP-I152L as a reporter of functional integrity of GlyRs. The protocol describes neuronal differentiation of NT2 stem cells, transient transfection of NT2-N cells with YFP-I152L as well as functional imaging and analysis of data from high-content imaging.
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Affiliation(s)
- Katharina Kuenzel
- Institute of Medical Biotechnology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052, Erlangen, Germany.
| | - Sepideh Abolpour Mofrad
- Institute of Medical Biotechnology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Paul-Gordan-Str. 3, 91052, Erlangen, Germany
| | - Daniel F Gilbert
- Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Institute of Medical Biotechnology, Paul-Gordan-Street 3, 91052, Erlangen, Germany
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14
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Janzen D, Schaefer N, Delto C, Schindelin H, Villmann C. The GlyR Extracellular β8-β9 Loop - A Functional Determinant of Agonist Potency. Front Mol Neurosci 2017; 10:322. [PMID: 29062270 PMCID: PMC5640878 DOI: 10.3389/fnmol.2017.00322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 09/22/2017] [Indexed: 01/07/2023] Open
Abstract
Ligand-binding of Cys-loop receptors results in rearrangements of extracellular loop structures which are further translated into the tilting of membrane spanning helices, and finally opening of the ion channels. The cryo-EM structure of the homopentameric α1 glycine receptor (GlyR) demonstrated an involvement of the extracellular β8–β9 loop in the transition from ligand-bound receptors to the open channel state. Recently, we identified a functional role of the β8–β9 loop in a novel startle disease mouse model shaky. The mutation of residue GlyRα1Q177 to lysine present in shaky mice resulted in reduced glycine potency, reduced synaptic expression, and a disrupted hydrogen network at the structural level around position GlyRα1Q177. Here, we investigated the role of amino acid volume, side chain length, and charge at position Q177 to get deeper insights into the functional role of the β8–β9 loop. We used a combined approach of in vitro expression analysis, functional electrophysiological recordings, and GlyR modeling to describe the role of Q177 for GlyR ion channel function. GlyRα1Q177 variants do not disturb ion channel transport to the cellular surface of transfected cells, neither in homomeric nor in heteromeric GlyR configurations. The EC50 values were increased for all GlyRα1Q177 variants in comparison to the wild type. The largest decrease in glycine potency was observed for the variant GlyRα1Q177R. Potencies of the partial agonists β-alanine and taurine were also reduced. Our data are further supported by homology modeling. The GlyRα1Q177R variant does not form hydrogen bonds with the surrounding network of residue Q177 similar to the substitution with a basic lysine present in the mouse mutant shaky. Among all investigated Q177 mutants, the neutral exchange of glutamine to asparagine as well as the introduction of the closely related amino acid glutamic acid preserve the hydrogen bond network. Introduction of amino acids with small side chains or larger volume resulted in a loss of their hydrogen bonds to neighboring residues. The β8–β9 loop is thus an important structural and functional determinant of the inhibitory GlyR.
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Affiliation(s)
- Dieter Janzen
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
| | - Natascha Schaefer
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
| | - Carolyn Delto
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Hermann Schindelin
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Carmen Villmann
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
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15
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Glycine receptor α3 and α2 subunits mediate tonic and exogenous agonist-induced currents in forebrain. Proc Natl Acad Sci U S A 2017; 114:E7179-E7186. [PMID: 28784756 DOI: 10.1073/pnas.1703839114] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Neuronal inhibition can occur via synaptic mechanisms or through tonic activation of extrasynaptic receptors. In spinal cord, glycine mediates synaptic inhibition through the activation of heteromeric glycine receptors (GlyRs) composed primarily of α1 and β subunits. Inhibitory GlyRs are also found throughout the brain, where GlyR α2 and α3 subunit expression exceeds that of α1, particularly in forebrain structures, and coassembly of these α subunits with the β subunit appears to occur to a lesser extent than in spinal cord. Here, we analyzed GlyR currents in several regions of the adolescent mouse forebrain (striatum, prefrontal cortex, hippocampus, amygdala, and bed nucleus of the stria terminalis). Our results show ubiquitous expression of GlyRs that mediate large-amplitude currents in response to exogenously applied glycine in these forebrain structures. Additionally, tonic inward currents were also detected, but only in the striatum, hippocampus, and prefrontal cortex (PFC). These tonic currents were sensitive to both strychnine and picrotoxin, indicating that they are mediated by extrasynaptic homomeric GlyRs. Recordings from mice deficient in the GlyR α3 subunit (Glra3-/-) revealed a lack of tonic GlyR currents in the striatum and the PFC. In Glra2-/Y animals, GlyR tonic currents were preserved; however, the amplitudes of current responses to exogenous glycine were significantly reduced. We conclude that functional α2 and α3 GlyRs are present in various regions of the forebrain and that α3 GlyRs specifically participate in tonic inhibition in the striatum and PFC. Our findings suggest roles for glycine in regulating neuronal excitability in the forebrain.
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16
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Förstera B, Muñoz B, Lobo MK, Chandra R, Lovinger DM, Aguayo LG. Presence of ethanol-sensitive glycine receptors in medium spiny neurons in the mouse nucleus accumbens. J Physiol 2017; 595:5285-5300. [PMID: 28524260 DOI: 10.1113/jp273767] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 05/05/2017] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS The nucleus accumbens (nAc) is involved in addiction-related behaviour caused by several drugs of abuse, including alcohol. Glycine receptors (GlyRs) are potentiated by ethanol and they have been implicated in the regulation of accumbal dopamine levels. We investigated the presence of GlyR subunits in nAc and their modulation by ethanol in medium spiny neurons (MSNs) of the mouse nAc. We found that the GlyR α1 subunit is preferentially expressed in nAc and is potentiated by ethanol. Our study shows that GlyR α1 in nAc is a new target for development of novel pharmacological tools for behavioural intervention in drug abuse. ABSTRACT Alcohol abuse causes major social, economic and health-related problems worldwide. Alcohol, like other drugs of abuse, increases levels of dopamine in the nucleus accumbens (nAc), facilitating behavioural reinforcement and substance abuse. Previous studies suggested that glycine receptors (GlyRs) are involved in the regulation of accumbal dopamine levels. Here, we investigated the presence of GlyRs in accumbal dopamine receptor medium spiny neurons (MSNs) of C57BL/6J mice, analysing mRNA expression levels and immunoreactivity of GlyR subunits, as well as ethanol sensitivity. We found that GlyR α1 subunits are expressed at higher levels than α2, α3 and β in the mouse nAc and were located preferentially in dopamine receptor 1 (DRD1)-positive MSNs. Interestingly, the glycine-evoked currents in dissociated DRD1-positive MSNs were potentiated by ethanol. Also, the potentiation of the GlyR-mediated tonic current by ethanol suggests that they modulate the excitability of DRD1-positive MSNs in nAc. This study should contribute to understanding the role of GlyR α1 in the reward system and might help to develop novel pharmacological therapies to treat alcoholism and other addiction-related and compulsive behaviours.
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Affiliation(s)
- B Förstera
- Department of Physiology, University of Concepcion, Concepcion, Chile
| | - B Muñoz
- Department of Physiology, University of Concepcion, Concepcion, Chile
| | - M K Lobo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, HSF II Rm 251, Baltimore, MD, 21201, USA
| | - R Chandra
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn Street, HSF II Rm 251, Baltimore, MD, 21201, USA
| | - D M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - L G Aguayo
- Department of Physiology, University of Concepcion, Concepcion, Chile
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17
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Morelli G, Avila A, Ravanidis S, Aourz N, Neve RL, Smolders I, Harvey RJ, Rigo JM, Nguyen L, Brône B. Cerebral Cortical Circuitry Formation Requires Functional Glycine Receptors. Cereb Cortex 2017; 27:1863-1877. [PMID: 26891984 DOI: 10.1093/cercor/bhw025] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The development of the cerebral cortex is a complex process that requires the generation, migration, and differentiation of neurons. Interfering with any of these steps can impair the establishment of connectivity and, hence, function of the adult brain. Neurotransmitter receptors have emerged as critical players to regulate these biological steps during brain maturation. Among them, α2 subunit-containing glycine receptors (GlyRs) regulate cortical neurogenesis and the present work demonstrates the long-term consequences of their genetic disruption on neuronal connectivity in the postnatal cerebral cortex. Our data indicate that somatosensory cortical neurons of Glra2 knockout mice (Glra2KO) have more dendritic branches with an overall increase in total spine number. These morphological defects correlate with a disruption of the excitation/inhibition balance, thereby increasing network excitability and enhancing susceptibility to epileptic seizures after pentylenetetrazol tail infusion. Taken together, our findings show that the loss of embryonic GlyRα2 ultimately impairs the formation of cortical circuits in the mature brain.
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Affiliation(s)
- Giovanni Morelli
- BIOMED Research Institute, Hasselt University, Hasselt 3500, Belgium.,GIGA-Neurosciences.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R)
| | - Ariel Avila
- Program in Neurosciences and Mental Health, SickKids Research Institute, The Hospital for Sick Children (SickKids), Toronto, ON, CanadaM5G 1X8
| | | | - Najat Aourz
- Department of Pharmaceutical Chemistry and Drug Analysis, C4N, Center for Neuroscience, Vrije Universiteit Brussel, 1090 Brussel, Belgium
| | - Rachael L Neve
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry and Drug Analysis, C4N, Center for Neuroscience, Vrije Universiteit Brussel, 1090 Brussel, Belgium
| | - Robert J Harvey
- Department of Pharmacology, UCL School of Pharmacy, London WC1N 1AX, UK
| | - Jean-Michel Rigo
- BIOMED Research Institute, Hasselt University, Hasselt 3500, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences.,Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R).,Walloon Excellence in Lifesciences and Biotechnology (WELBIO), University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Bert Brône
- BIOMED Research Institute, Hasselt University, Hasselt 3500, Belgium
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18
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Lynch JW, Zhang Y, Talwar S, Estrada-Mondragon A. Glycine Receptor Drug Discovery. ADVANCES IN PHARMACOLOGY 2017; 79:225-253. [DOI: 10.1016/bs.apha.2017.01.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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19
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Meier JC, Kankowski S, Krestel H, Hetsch F. RNA Editing-Systemic Relevance and Clue to Disease Mechanisms? Front Mol Neurosci 2016; 9:124. [PMID: 27932948 PMCID: PMC5120146 DOI: 10.3389/fnmol.2016.00124] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 11/04/2016] [Indexed: 11/13/2022] Open
Abstract
Recent advances in sequencing technologies led to the identification of a plethora of different genes and several hundreds of amino acid recoding edited positions. Changes in editing rates of some of these positions were associated with diseases such as atherosclerosis, myopathy, epilepsy, major depression disorder, schizophrenia and other mental disorders as well as cancer and brain tumors. This review article summarizes our current knowledge on that front and presents glycine receptor C-to-U RNA editing as a first example of disease-associated increased RNA editing that includes assessment of disease mechanisms of the corresponding gene product in an animal model.
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Affiliation(s)
- Jochen C Meier
- Cell Physiology, Technische Universität Braunschweig Braunschweig, Germany
| | - Svenja Kankowski
- Cell Physiology, Technische Universität Braunschweig Braunschweig, Germany
| | - Heinz Krestel
- Neurology, Universitätsspital und Universität Bern Bern, Switzerland
| | - Florian Hetsch
- Cell Physiology, Technische Universität Braunschweig Braunschweig, Germany
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20
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Breitinger U, Sticht H, Breitinger HG. Modulation of Recombinant Human α1 Glycine Receptors by Mono- and Disaccharides: A Kinetic Study. ACS Chem Neurosci 2016; 7:1077-87. [PMID: 27227552 DOI: 10.1021/acschemneuro.6b00044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Glycine receptors (GlyRs) mediate fast synaptic inhibition in spinal cord, brainstem, and higher brain centers. Recently, glucose was identified as a positive modulator of GlyR-mediated currents. Here, we investigated extent and kinetics of the positive modulation of recombinant human α1 glycine receptors by different mono- and disaccharides and sorbitol using patch-clamp recording techniques. Glucose and fructose augmented glycine-mediated whole-cell currents with an EC50 of 6-7 mM. At concentrations > 10 mM, the maximum of current enhancement was reached within ∼30 min. Kinetics of GlyR modulation resemble those of protein glycation. On-rates were <0.5 h for saturating concentrations of monosaccharides and ∼1.5 h for disaccharides. Off-rates were considerably slower (>24 h). Galactose, the C4-epimer of glucose, and the sugar alcohol sorbitol had no effect on GlyR currents. Recent cryoelectron microscopy structures were used to identify a potential binding site for saccharides near the ivermectin binding pocket with lysine 143 as possible attachment site. The GlyR mutant α1(K143A) was not potentiated by glucose, suggesting an involvement of this residue in glycine receptor modulation by saccharides.
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Affiliation(s)
- Ulrike Breitinger
- Department
of Biochemistry, The German University in Cairo, Main Entrance
of Al Tagamoa Al Khames, New Cairo 11835, Egypt
| | - Heinrich Sticht
- Bioinformatics, Institute for Biochemistry, Friedrich-Alexander-Universität Erlangen-Nümberg, Fahrstrasse 17, D-91054 Erlangen, Germany
| | - Hans-Georg Breitinger
- Department
of Biochemistry, The German University in Cairo, Main Entrance
of Al Tagamoa Al Khames, New Cairo 11835, Egypt
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21
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Raltschev C, Hetsch F, Winkelmann A, Meier JC, Semtner M. Electrophysiological Signature of Homomeric and Heteromeric Glycine Receptor Channels. J Biol Chem 2016; 291:18030-40. [PMID: 27382060 DOI: 10.1074/jbc.m116.735084] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 11/06/2022] Open
Abstract
Glycine receptors are chloride-permeable, ligand-gated ion channels and contribute to the inhibition of neuronal firing in the central nervous system or to facilitation of neurotransmitter release if expressed at presynaptic sites. Recent structure-function studies have provided detailed insights into the mechanisms of channel gating, desensitization, and ion permeation. However, most of the work has focused only on comparing a few isoforms, and among studies, different cellular expression systems were used. Here, we performed a series of experiments using recombinantly expressed homomeric and heteromeric glycine receptor channels, including their splice variants, in the same cellular expression system to investigate and compare their electrophysiological properties. Our data show that the current-voltage relationships of homomeric channels formed by the α2 or α3 subunits change upon receptor desensitization from a linear to an inwardly rectifying shape, in contrast to their heteromeric counterparts. The results demonstrate that inward rectification depends on a single amino acid (Ala(254)) at the inner pore mouth of the channels and is closely linked to chloride permeation. We also show that the current-voltage relationships of glycine-evoked currents in primary hippocampal neurons are inwardly rectifying upon desensitization. Thus, the alanine residue Ala(254) determines voltage-dependent rectification upon receptor desensitization and reveals a physio-molecular signature of homomeric glycine receptor channels, which provides unprecedented opportunities for the identification of these channels at the single cell level.
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Affiliation(s)
- Constanze Raltschev
- From the Department of Biomedicine, Cellular Neurophysiology, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Florian Hetsch
- the Division of Cell Physiology, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany, and
| | - Aline Winkelmann
- the Division of Cell Physiology, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany, and
| | - Jochen C Meier
- the Division of Cell Physiology, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany, and
| | - Marcus Semtner
- Cellular Neurosciences, Max-Delbrück-Centrum für Molekulare Medizin (MDC), Robert-Rössle-Strasse 10, 13092 Berlin, Germany
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22
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Ogino K, Hirata H. Defects of the Glycinergic Synapse in Zebrafish. Front Mol Neurosci 2016; 9:50. [PMID: 27445686 PMCID: PMC4925712 DOI: 10.3389/fnmol.2016.00050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/13/2016] [Indexed: 12/26/2022] Open
Abstract
Glycine mediates fast inhibitory synaptic transmission. Physiological importance of the glycinergic synapse is well established in the brainstem and the spinal cord. In humans, the loss of glycinergic function in the spinal cord and brainstem leads to hyperekplexia, which is characterized by an excess startle reflex to sudden acoustic or tactile stimulation. In addition, glycinergic synapses in this region are also involved in the regulation of respiration and locomotion, and in the nociceptive processing. The importance of the glycinergic synapse is conserved across vertebrate species. A teleost fish, the zebrafish, offers several advantages as a vertebrate model for research of glycinergic synapse. Mutagenesis screens in zebrafish have isolated two motor defective mutants that have pathogenic mutations in glycinergic synaptic transmission: bandoneon (beo) and shocked (sho). Beo mutants have a loss-of-function mutation of glycine receptor (GlyR) β-subunit b, alternatively, sho mutant is a glycinergic transporter 1 (GlyT1) defective mutant. These mutants are useful animal models for understanding of glycinergic synaptic transmission and for identification of novel therapeutic agents for human diseases arising from defect in glycinergic transmission, such as hyperekplexia or glycine encephalopathy. Recent advances in techniques for genome editing and for imaging and manipulating of a molecule or a physiological process make zebrafish more attractive model. In this review, we describe the glycinergic defective zebrafish mutants and the technical advances in both forward and reverse genetic approaches as well as in vivo visualization and manipulation approaches for the study of the glycinergic synapse in zebrafish.
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Affiliation(s)
- Kazutoyo Ogino
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University Sagamihara, Japan
| | - Hiromi Hirata
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University Sagamihara, Japan
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23
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Kuenzel K, Friedrich O, Gilbert DF. A Recombinant Human Pluripotent Stem Cell Line Stably Expressing Halide-Sensitive YFP-I152L for GABAAR and GlyR-Targeted High-Throughput Drug Screening and Toxicity Testing. Front Mol Neurosci 2016; 9:51. [PMID: 27445687 PMCID: PMC4923258 DOI: 10.3389/fnmol.2016.00051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/13/2016] [Indexed: 01/29/2023] Open
Abstract
GABAARs and GlyRs are considered attractive drug targets for therapeutic intervention and are also increasingly recognized in the context of in vitro neurotoxicity (NT) and developmental neurotoxicity (DNT) testing. However, systematic human-specific GABAAR and GlyR-targeted drug screening and toxicity testing is hampered due to lack of appropriate in vitro models that express native GABAARs and GlyRs. We have established a human pluripotent stem cell line (NT2) stably expressing YFP-I152L, a halide-sensitive variant of yellow fluorescent protein (YFP), allowing for fluorescence-based functional analysis of chloride channels. Upon stimulation with retinoic acid, NT2 cells undergo neuronal differentiation and allow pharmacological and toxicological evaluation of native GABAARs and GlyRs at different stages of brain maturation. We applied the cell line in concentration-response experiments with the neurotransmitters GABA and glycine as well as with the drugs strychnine, picrotoxin, fipronil, lindane, bicuculline, and zinc and demonstrate that the established in vitro model is applicable to GABAAR and GlyR-targeted pharmacological and toxicological profiling. We quantified the proportion of GABAAR and GlyR-sensitive cells, respectively, and identified percentages of approximately 20% each within the overall populations, rendering the cells a suitable model for systematic in vitro GABAAR and GlyR-targeted screening in the context of drug development and NT/DNT testing.
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Affiliation(s)
- Katharina Kuenzel
- Department of Chemical and Biological Engineering, Institute of Medical Biotechnology, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany; Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany
| | - Oliver Friedrich
- Department of Chemical and Biological Engineering, Institute of Medical Biotechnology, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany; Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany
| | - Daniel F Gilbert
- Department of Chemical and Biological Engineering, Institute of Medical Biotechnology, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany; Erlangen Graduate School in Advanced Optical Technologies, Friedrich-Alexander-Universität Erlangen-NürnbergErlangen, Germany
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24
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Langlhofer G, Villmann C. The Intracellular Loop of the Glycine Receptor: It's not all about the Size. Front Mol Neurosci 2016; 9:41. [PMID: 27330534 PMCID: PMC4891346 DOI: 10.3389/fnmol.2016.00041] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 05/17/2016] [Indexed: 11/15/2022] Open
Abstract
The family of Cys-loop receptors (CLRs) shares a high degree of homology and sequence identity. The overall structural elements are highly conserved with a large extracellular domain (ECD) harboring an α-helix and 10 β-sheets. Following the ECD, four transmembrane domains (TMD) are connected by intracellular and extracellular loop structures. Except the TM3–4 loop, their length comprises 7–14 residues. The TM3–4 loop forms the largest part of the intracellular domain (ICD) and exhibits the most variable region between all CLRs. The ICD is defined by the TM3–4 loop together with the TM1–2 loop preceding the ion channel pore. During the last decade, crystallization approaches were successful for some members of the CLR family. To allow crystallization, the intracellular loop was in most structures replaced by a short linker present in prokaryotic CLRs. Therefore, no structural information about the large TM3–4 loop of CLRs including the glycine receptors (GlyRs) is available except for some basic stretches close to TM3 and TM4. The intracellular loop has been intensively studied with regard to functional aspects including desensitization, modulation of channel physiology by pharmacological substances, posttranslational modifications, and motifs important for trafficking. Furthermore, the ICD interacts with scaffold proteins enabling inhibitory synapse formation. This review focuses on attempts to define structural and functional elements within the ICD of GlyRs discussed with the background of protein-protein interactions and functional channel formation in the absence of the TM3–4 loop.
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Affiliation(s)
- Georg Langlhofer
- Institute of Clinical Neurobiology, University of Würzburg Würzburg, Germany
| | - Carmen Villmann
- Institute of Clinical Neurobiology, University of Würzburg Würzburg, Germany
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25
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Förstera B, Castro PA, Moraga-Cid G, Aguayo LG. Potentiation of Gamma Aminobutyric Acid Receptors (GABAAR) by Ethanol: How Are Inhibitory Receptors Affected? Front Cell Neurosci 2016; 10:114. [PMID: 27199667 PMCID: PMC4858537 DOI: 10.3389/fncel.2016.00114] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/20/2016] [Indexed: 01/10/2023] Open
Abstract
In recent years there has been an increase in the understanding of ethanol actions on the type A γ-aminobutyric acid chloride channel (GABAAR), a member of the pentameric ligand gated ion channels (pLGICs). However, the mechanism by which ethanol potentiates the complex is still not fully understood and a number of publications have shown contradictory results. Thus many questions still remain unresolved requiring further studies for a better comprehension of this effect. The present review concentrates on the involvement of GABAAR in the acute actions of ethanol and specifically focuses on the immediate, direct or indirect, synaptic and extra-synaptic modulatory effects. To elaborate on the immediate, direct modulation of GABAAR by acute ethanol exposure, electrophysiological studies investigating the importance of different subunits, and data from receptor mutants will be examined. We will also discuss the nature of the putative binding sites for ethanol based on structural data obtained from other members of the pLGICs family. Finally, we will briefly highlight the glycine gated chloride channel (GlyR), another member of the pLGIC family, as a suitable target for the development of new pharmacological tools.
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Affiliation(s)
- Benjamin Förstera
- Laboratory of Neurophysiology, Department of Physiology, University of Concepcion Concepcion, Chile
| | - Patricio A Castro
- Laboratory of Environmental Neurotoxicology, Department of Biomedical Sciences, Faculty of Medicine, Universidad Católica del Norte Coquimbo, Chile
| | - Gustavo Moraga-Cid
- Hindbrain Integrative Neurobiology Laboratory, Institut de Neurobiologie Alfred Fessard Gif-Sur-Yvette, France
| | - Luis G Aguayo
- Laboratory of Neurophysiology, Department of Physiology, University of Concepcion Concepcion, Chile
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26
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Çaliskan G, Müller I, Semtner M, Winkelmann A, Raza AS, Hollnagel JO, Rösler A, Heinemann U, Stork O, Meier JC. Identification of Parvalbumin Interneurons as Cellular Substrate of Fear Memory Persistence. Cereb Cortex 2016; 26:2325-2340. [PMID: 26908632 PMCID: PMC4830301 DOI: 10.1093/cercor/bhw001] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Parvalbumin-positive (PV) basket cells provide perisomatic inhibition in the cortex and hippocampus and control generation of memory-related network activity patterns, such as sharp wave ripples (SPW-R). Deterioration of this class of fast-spiking interneurons has been observed in neuropsychiatric disorders and evidence from animal models suggests their involvement in the acquisition and extinction of fear memories. Here, we used mice with neuron type-targeted expression of the presynaptic gain-of-function glycine receptor RNA variant GlyR α3L185L to genetically enhance the network activity of PV interneurons. These mice showed reduced extinction of contextual fear memory but normal auditory cued fear memory. They furthermore displayed increase of SPW-R activity in area CA3 and CA1 and facilitated propagation of this particular network activity pattern, as determined in ventral hippocampal slice preparations. Individual freezing levels during extinction and SPW-R propagation were correlated across genotypes. The same was true for parvalbumin immunoreactivity in the ventral hippocampus, which was generally augmented in the GlyR mutant mice and correlated with individual freezing levels. Together, these results identify PV interneurons as critical cellular substrate of fear memory persistence and associated SPW-R activity in the hippocampus. Our findings may be relevant for the identification and characterization of physiological correlates for posttraumatic stress and anxiety disorders.
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Affiliation(s)
- Gürsel Çaliskan
- Institute for Neurophysiology, Charité Universitätsmedizin Berlin, Berlin 14195, Germany.,Institute of Biology, Department of Genetics and Molecular Neurobiology, Otto-von-Guericke-University, Magdeburg 39120, Germany
| | - Iris Müller
- Institute of Biology, Department of Genetics and Molecular Neurobiology, Otto-von-Guericke-University, Magdeburg39120, Germany
| | - Marcus Semtner
- Division Cell Physiology, Zoological Institute, Braunschweig38106, Germany
| | - Aline Winkelmann
- Division Cell Physiology, Zoological Institute, Braunschweig 38106, Germany.,RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Ahsan S Raza
- Institute of Biology, Department of Genetics and Molecular Neurobiology, Otto-von-Guericke-University, Magdeburg39120, Germany
| | - Jan O Hollnagel
- Institute for Neurophysiology, Charité Universitätsmedizin Berlin, Berlin 14195, Germany.,Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg 69120, Germany
| | - Anton Rösler
- Institute for Neurophysiology, Charité Universitätsmedizin Berlin, Berlin14195, Germany
| | - Uwe Heinemann
- Institute for Neurophysiology, Charité Universitätsmedizin Berlin, Berlin14195, Germany
| | - Oliver Stork
- Institute of Biology, Department of Genetics and Molecular Neurobiology, Otto-von-Guericke-University, Magdeburg 39120, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Jochen C Meier
- Division Cell Physiology, Zoological Institute, Braunschweig 38106, Germany.,RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
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27
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Breitinger U, Breitinger HG. Augmentation of glycine receptor alpha3 currents suggests a mechanism for glucose-mediated analgesia. Neurosci Lett 2016; 612:110-115. [DOI: 10.1016/j.neulet.2015.11.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/17/2015] [Accepted: 11/30/2015] [Indexed: 11/16/2022]
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Dixon CL, Zhang Y, Lynch JW. Generation of Functional Inhibitory Synapses Incorporating Defined Combinations of GABA(A) or Glycine Receptor Subunits. Front Mol Neurosci 2015; 8:80. [PMID: 26778954 PMCID: PMC4688394 DOI: 10.3389/fnmol.2015.00080] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/07/2015] [Indexed: 11/13/2022] Open
Abstract
Fast inhibitory neurotransmission in the brain is mediated by wide range of GABAA receptor (GABAAR) and glycine receptor (GlyR) isoforms, each with different physiological and pharmacological properties. Because multiple isoforms are expressed simultaneously in most neurons, it is difficult to define the properties of individual isoforms under synaptic stimulation conditions in vivo. Although recombinant expression systems permit the expression of individual isoforms in isolation, they require exogenous agonist application which cannot mimic the dynamic neurotransmitter profile characteristic of native synapses. We describe a neuron-HEK293 cell co-culture technique for generating inhibitory synapses incorporating defined combinations of GABAAR or GlyR subunits. Primary neuronal cultures, prepared from embryonic rat cerebral cortex or spinal cord, are used to provide presynaptic GABAergic and glycinergic terminals, respectively. When the cultures are mature, HEK293 cells expressing the subunits of interest plus neuroligin 2A are plated onto the neurons, which rapidly form synapses onto HEK293 cells. Patch clamp electrophysiology is then used to analyze the physiological and pharmacological properties of the inhibitory postsynaptic currents mediated by the recombinant receptors. The method is suitable for investigating the kinetic properties or the effects of drugs on inhibitory postsynaptic currents mediated by defined GABAAR or GlyR isoforms of interest, the effects of hereditary disease mutations on the formation and function of both types of synapses, and synaptogenesis and synaptic clustering mechanisms. The entire cell preparation procedure takes 2-5 weeks.
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Affiliation(s)
- Christine L Dixon
- Queensland Brain Institute, University of Queensland Brisbane, QLD, Australia
| | - Yan Zhang
- Queensland Brain Institute, University of Queensland Brisbane, QLD, Australia
| | - Joseph W Lynch
- Queensland Brain Institute, University of QueenslandBrisbane, QLD, Australia; School of Biomedical Sciences, University of QueenslandBrisbane, QLD, Australia
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29
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Aroeira RI, Sebastião AM, Valente CA. BDNF, via truncated TrkB receptor, modulates GlyT1 and GlyT2 in astrocytes. Glia 2015. [DOI: 10.1002/glia.22884] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Rita I. Aroeira
- Faculty of Medicine, Institute of Pharmacology and Neurosciences, and Unit of Neurosciences, Institute of Molecular Medicine, University of Lisbon; Av. Prof. Egas Moniz Lisbon Portugal
| | - Ana M. Sebastião
- Faculty of Medicine, Institute of Pharmacology and Neurosciences, and Unit of Neurosciences, Institute of Molecular Medicine, University of Lisbon; Av. Prof. Egas Moniz Lisbon Portugal
| | - Cláudia A. Valente
- Faculty of Medicine, Institute of Pharmacology and Neurosciences, and Unit of Neurosciences, Institute of Molecular Medicine, University of Lisbon; Av. Prof. Egas Moniz Lisbon Portugal
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30
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Winkelmann A, Semtner M, Meier JC. Chloride transporter KCC2-dependent neuroprotection depends on the N-terminal protein domain. Cell Death Dis 2015; 6:e1776. [PMID: 26043076 PMCID: PMC4669822 DOI: 10.1038/cddis.2015.127] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 03/27/2015] [Accepted: 03/30/2015] [Indexed: 01/04/2023]
Abstract
Neurodegeneration is a serious issue of neurodegenerative diseases including epilepsy. Downregulation of the chloride transporter KCC2 in the epileptic tissue may not only affect regulation of the polarity of GABAergic synaptic transmission but also neuronal survival. Here, we addressed the mechanisms of KCC2-dependent neuroprotection by assessing truncated and mutated KCC2 variants in different neurotoxicity models. The results identify a threonine- and tyrosine-phosphorylation-resistant KCC2 variant with increased chloride transport activity, but they also identify the KCC2 N-terminal domain (NTD) as the relevant minimal KCC2 protein domain that is sufficient for neuroprotection. As ectopic expression of the KCC2-NTD works independently of full-length KCC2-dependent regulation of Cl(-) transport or structural KCC2 C-terminus-dependent regulation of synaptogenesis, our study may pave the way for a selective neuroprotective therapeutic strategy that will be applicable to a wide range of neurodegenerative diseases.
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Affiliation(s)
- A Winkelmann
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - M Semtner
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
| | - J C Meier
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin 13125, Germany
- Division of Cell Physiology, TU Braunschweig, Zoological Institute, Braunschweig 38106, Germany
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31
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Winkelmann A, You X, Grünewald N, Häussler U, Krestel H, Haas CA, Schwarz G, Chen W, Meier JC. Identification of a new genomic hot spot of evolutionary diversification of protein function. PLoS One 2015; 10:e0125413. [PMID: 25955356 PMCID: PMC4425505 DOI: 10.1371/journal.pone.0125413] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 03/23/2015] [Indexed: 01/06/2023] Open
Abstract
Establishment of phylogenetic relationships remains a challenging task because it is based on computational analysis of genomic hot spots that display species-specific sequence variations. Here, we identify a species-specific thymine-to-guanine sequence variation in the Glrb gene which gives rise to species-specific splice donor sites in the Glrb genes of mouse and bushbaby. The resulting splice insert in the receptor for the inhibitory neurotransmitter glycine (GlyR) conveys synaptic receptor clustering and specific association with a particular synaptic plasticity-related splice variant of the postsynaptic scaffold protein gephyrin. This study identifies a new genomic hot spot which contributes to phylogenetic diversification of protein function and advances our understanding of phylogenetic relationships.
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Affiliation(s)
- Aline Winkelmann
- RNA editing and Hyperexcitability Disorders Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Xiantian You
- Laboratory of Functional and Medical Genomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nora Grünewald
- Department of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany
| | - Ute Häussler
- Department of Neurosurgery, University of Freiburg, Freiburg, Germany
| | - Heinz Krestel
- Department of Neurology, Bern University Hospital, Bern, Switzerland
| | - Carola A. Haas
- Department of Neurosurgery, University of Freiburg, Freiburg, Germany
| | - Günter Schwarz
- Department of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany
| | - Wei Chen
- Laboratory of Functional and Medical Genomics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jochen C. Meier
- RNA editing and Hyperexcitability Disorders Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Life Science Department, Zoological Institute, Division of Cell Physiology, TU Braunschweig, Braunschweig, Germany
- * E-mail:
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32
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Blednov YA, Benavidez JM, Black M, Leiter CR, Osterndorff-Kahanek E, Harris RA. Glycine receptors containing α2 or α3 subunits regulate specific ethanol-mediated behaviors. J Pharmacol Exp Ther 2015; 353:181-91. [PMID: 25678534 DOI: 10.1124/jpet.114.221895] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glycine receptors (GlyRs) are broadly expressed in the central nervous system. Ethanol enhances the function of brain GlyRs, and the GlyRα1 subunit is associated with some of the behavioral actions of ethanol, such as loss of righting reflex. The in vivo role of GlyRα2 and α3 subunits in alcohol responses has not been characterized despite high expression levels in the nucleus accumbens and amygdala, areas that are important for the rewarding properties of drugs of abuse. We used an extensive panel of behavioral tests to examine ethanol actions in mice lacking Glra2 (the gene encoding the glycine receptor alpha 2 subunit) or Glra3 (the gene encoding the glycine receptor alpha 3 subunit). Deletion of Glra2 or Glra3 alters specific ethanol-induced behaviors. Glra2 knockout mice demonstrate reduced ethanol intake and preference in the 24-hour two-bottle choice test and increased initial aversive responses to ethanol and lithium chloride. In contrast, Glra3 knockout mice show increased ethanol intake and preference in the 24-hour intermittent access test and increased development of conditioned taste aversion to ethanol. Mutants and wild-type mice consumed similar amounts of ethanol in the limited access drinking in the dark test. Other ethanol effects, such as anxiolysis, motor incoordination, loss of righting reflex, and acoustic startle response, were not altered in the mutants. The behavioral changes in mice lacking GlyRα2 or α3 subunits were distinct from effects previously observed in mice with knock-in mutations in the α1 subunit. We provide evidence that GlyRα2 and α3 subunits may regulate ethanol consumption and the aversive response to ethanol.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Jillian M Benavidez
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Mendy Black
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Courtney R Leiter
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | | | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
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33
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Naito A, Muchhala KH, Asatryan L, Trudell JR, Homanics GE, Perkins DI, Davies DL, Alkana RL. Glycine and GABA(A) ultra-sensitive ethanol receptors as novel tools for alcohol and brain research. Mol Pharmacol 2014; 86:635-46. [PMID: 25245406 DOI: 10.1124/mol.114.093773] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A critical obstacle to developing effective medications to prevent and/or treat alcohol use disorders is the lack of specific knowledge regarding the plethora of molecular targets and mechanisms underlying alcohol (ethanol) action in the brain. To identify the role of individual receptor subunits in ethanol-induced behaviors, we developed a novel class of ultra-sensitive ethanol receptors (USERs) that allow activation of a single receptor subunit population sensitized to extremely low ethanol concentrations. USERs were created by mutating as few as four residues in the extracellular loop 2 region of glycine receptors (GlyRs) or γ-aminobutyric acid type A receptors (GABA(A)Rs), which are implicated in causing many behavioral effects linked to ethanol abuse. USERs, expressed in Xenopus oocytes and tested using two-electrode voltage clamp, demonstrated an increase in ethanol sensitivity of 100-fold over wild-type receptors by significantly decreasing the threshold and increasing the magnitude of ethanol response, without altering general receptor properties including sensitivity to the neurosteroid, allopregnanolone. These profound changes in ethanol sensitivity were observed across multiple subunits of GlyRs and GABA(A)Rs. Collectively, our studies set the stage for using USER technology in genetically engineered animals as a unique tool to increase understanding of the neurobiological basis of the behavioral effects of ethanol.
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Affiliation(s)
- Anna Naito
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - Karan H Muchhala
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - Liana Asatryan
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - James R Trudell
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - Gregg E Homanics
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - Daya I Perkins
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - Daryl L Davies
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
| | - Ronald L Alkana
- Department of Pharmacology and Pharmaceutical Sciences (A.N., K.H.M., R.L.A.) and Titus Family Department of Clinical Pharmacy and Pharmaceutical Economics and Policy (L.A., D.L.D.), University of Southern California School of Pharmacy, Los Angeles, California; Department of Anesthesia, Beckman Program for Molecular and Genetic Medicine, Stanford University, Stanford University Medical Center, Stanford, California (J.R.T.); Departments of Anesthesiology and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania (G.E.H.); and Amgen Inc., Thousand Oaks, California (D.I.P.)
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Kasim M, Benko E, Winkelmann A, Mrowka R, Staudacher JJ, Persson PB, Scholz H, Meier JC, Fähling M. Shutdown of achaete-scute homolog-1 expression by heterogeneous nuclear ribonucleoprotein (hnRNP)-A2/B1 in hypoxia. J Biol Chem 2014; 289:26973-26988. [PMID: 25124043 DOI: 10.1074/jbc.m114.579391] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The basic helix-loop-helix transcription factor hASH1, encoded by the ASCL1 gene, plays an important role in neurogenesis and tumor development. Recent findings indicate that local oxygen tension is a critical determinant for the progression of neuroblastomas. Here we investigated the molecular mechanisms underlying the oxygen-dependent expression of hASH1 in neuroblastoma cells. Exposure of human neuroblastoma-derived Kelly cells to 1% O2 significantly decreased ASCL1 mRNA and hASH1 protein levels. Using reporter gene assays, we show that the response of hASH1 to hypoxia is mediated mainly by post-transcriptional inhibition via the ASCL1 mRNA 5'- and 3'-UTRs, whereas additional inhibition of the ASCL1 promoter was observed under prolonged hypoxia. By RNA pulldown experiments followed by MALDI/TOF-MS analysis, we identified heterogeneous nuclear ribonucleoprotein (hnRNP)-A2/B1 and hnRNP-R as interactors binding directly to the ASCL1 mRNA 5'- and 3'-UTRs and influencing its expression. We further demonstrate that hnRNP-A2/B1 is a key positive regulator of ASCL1, findings that were also confirmed by analysis of a large compilation of gene expression data. Our data suggest that a prominent down-regulation of hnRNP-A2/B1 during hypoxia is associated with the post-transcriptional suppression of hASH1 synthesis. This novel post-transcriptional mechanism for regulating hASH1 levels will have important implications in neural cell fate development and disease.
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Affiliation(s)
- Mumtaz Kasim
- Institut für Vegetative Physiologie, Charité-Universitätsmedizin Berlin, D-10117 Berlin
| | - Edgar Benko
- Institut für Vegetative Physiologie, Charité-Universitätsmedizin Berlin, D-10117 Berlin
| | - Aline Winkelmann
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, D-13125 Berlin, and
| | - Ralf Mrowka
- Klinik für Innere Medizin III, AG Experimentelle Nephrologie, Universitätsklinikum Jena, D-07743 Jena, Germany
| | - Jonas J Staudacher
- Institut für Vegetative Physiologie, Charité-Universitätsmedizin Berlin, D-10117 Berlin
| | - Pontus B Persson
- Institut für Vegetative Physiologie, Charité-Universitätsmedizin Berlin, D-10117 Berlin
| | - Holger Scholz
- Institut für Vegetative Physiologie, Charité-Universitätsmedizin Berlin, D-10117 Berlin
| | - Jochen C Meier
- RNA Editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, D-13125 Berlin, and
| | - Michael Fähling
- Institut für Vegetative Physiologie, Charité-Universitätsmedizin Berlin, D-10117 Berlin,.
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35
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Schaefer N, Langlhofer G, Kluck CJ, Villmann C. Glycine receptor mouse mutants: model systems for human hyperekplexia. Br J Pharmacol 2014; 170:933-52. [PMID: 23941355 DOI: 10.1111/bph.12335] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 07/19/2013] [Accepted: 08/02/2013] [Indexed: 11/30/2022] Open
Abstract
Human hyperekplexia is a neuromotor disorder caused by disturbances in inhibitory glycine-mediated neurotransmission. Mutations in genes encoding for glycine receptor subunits or associated proteins, such as GLRA1, GLRB, GPHN and ARHGEF9, have been detected in patients suffering from hyperekplexia. Classical symptoms are exaggerated startle attacks upon unexpected acoustic or tactile stimuli, massive tremor, loss of postural control during startle and apnoea. Usually patients are treated with clonazepam, this helps to dampen the severe symptoms most probably by up-regulating GABAergic responses. However, the mechanism is not completely understood. Similar neuromotor phenotypes have been observed in mouse models that carry glycine receptor mutations. These mouse models serve as excellent tools for analysing the underlying pathomechanisms. Yet, studies in mutant mice looking for postsynaptic compensation of glycinergic dysfunction via an up-regulation in GABAA receptor numbers have failed, as expression levels were similar to those in wild-type mice. However, presynaptic adaptation mechanisms with an unusual switch from mixed GABA/glycinergic to GABAergic presynaptic terminals have been observed. Whether this presynaptic adaptation explains the improvement in symptoms or other compensation mechanisms exist is still under investigation. With the help of spontaneous glycine receptor mouse mutants, knock-in and knock-out studies, it is possible to associate behavioural changes with pharmacological differences in glycinergic inhibition. This review focuses on the structural and functional characteristics of the various mouse models used to elucidate the underlying signal transduction pathways and adaptation processes and describes a novel route that uses gene-therapeutic modulation of mutated receptors to overcome loss of function mutations.
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Affiliation(s)
- Natascha Schaefer
- Institute for Clinical Neurobiology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
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36
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Meier JC, Meier J, Semtner M, Winkelmann A, Wolfart J. Presynaptic mechanisms of neuronal plasticity and their role in epilepsy. Front Cell Neurosci 2014; 8:164. [PMID: 24987332 PMCID: PMC4060558 DOI: 10.3389/fncel.2014.00164] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 05/29/2014] [Indexed: 11/17/2022] Open
Abstract
Synaptic communication requires constant adjustments of pre- and postsynaptic efficacies. In addition to synaptic long term plasticity, the presynaptic machinery underlies homeostatic regulations which prevent out of range transmitter release. In this minireview we will discuss the relevance of selected presynaptic mechanisms to epilepsy including voltage- and ligand-gated ion channels as well as cannabinoid and adenosine receptor signaling.
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Affiliation(s)
| | - Jochen Meier
- RNA Editing and Hyperexcitability Disorders, Max Delbrück Centre for Molecular Medicine, Neurosciences Berlin, Germany
| | - Marcus Semtner
- RNA Editing and Hyperexcitability Disorders, Max Delbrück Centre for Molecular Medicine, Neurosciences Berlin, Germany
| | - Aline Winkelmann
- RNA Editing and Hyperexcitability Disorders, Max Delbrück Centre for Molecular Medicine, Neurosciences Berlin, Germany
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
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Chen R, Okabe A, Sun H, Sharopov S, Hanganu-Opatz IL, Kolbaev SN, Fukuda A, Luhmann HJ, Kilb W. Activation of glycine receptors modulates spontaneous epileptiform activity in the immature rat hippocampus. J Physiol 2014; 592:2153-68. [PMID: 24665103 DOI: 10.1113/jphysiol.2014.271700] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
While the expression of glycine receptors in the immature hippocampus has been shown, no information about the role of glycine receptors in controlling the excitability in the immature CNS is available. Therefore, we examined the effect of glycinergic agonists and antagonists in the CA3 region of an intact corticohippocampal preparation of the immature (postnatal days 4-7) rat using field potential recordings. Bath application of 100 μM taurine or 10 μM glycine enhanced the occurrence of recurrent epileptiform activity induced by 20 μM 4-aminopyridine in low Mg(2+) solution. This proconvulsive effect was prevented by 3 μM strychnine or after incubation with the loop diuretic bumetanide (10 μM), suggesting that it required glycine receptors and an active NKCC1-dependent Cl(-) accumulation. Application of higher doses of taurine (≥ 1 mM) or glycine (100 μM) attenuated recurrent epileptiform discharges. The anticonvulsive effect of taurine was also observed in the presence of the GABAA receptor antagonist gabazine and was attenuated by strychnine, suggesting that it was partially mediated by glycine receptors. Bath application of the glycinergic antagonist strychnine (0.3 μM) induced epileptiform discharges. We conclude from these results that in the immature hippocampus, activation of glycine receptors can mediate both pro- and anticonvulsive effects, but that a persistent activation of glycine receptors is required to suppress epileptiform activity. In summary, our study elucidated the important role of glycine receptors in the control of neuronal excitability in the immature hippocampus.
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Affiliation(s)
- Rongqing Chen
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Akihito Okabe
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany Department of Molecular Anatomy, School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa, 903-0215, Japan
| | - Haiyan Sun
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Salim Sharopov
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Ileana L Hanganu-Opatz
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany University Medical Center Hamburg Eppendorf, Developmental Neurophysiology, Falkenried 94, D-20251, Hamburg, Germany
| | - Sergei N Kolbaev
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55120, Mainz, Germany
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38
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Analysis of α3 GlyR single particle tracking in the cell membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:544-53. [DOI: 10.1016/j.bbamcr.2013.11.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/22/2013] [Accepted: 11/25/2013] [Indexed: 11/23/2022]
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39
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Notelaers K, Rocha S, Paesen R, Swinnen N, Vangindertael J, Meier JC, Rigo JM, Ameloot M, Hofkens J. Membrane distribution of the glycine receptor α3 studied by optical super-resolution microscopy. Histochem Cell Biol 2014; 142:79-90. [PMID: 24553792 DOI: 10.1007/s00418-014-1197-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2014] [Indexed: 11/24/2022]
Abstract
In this study, the effect of glycine receptor (GlyR) α3 alternative RNA splicing on the distribution of receptors in the membrane of human embryonic kidney 293 cells is investigated using optical super-resolution microscopy. Direct stochastic optical reconstruction microscopy is used to image both α3K and α3L splice variants individually and together using single- and dual-color imaging. Pair correlation analysis is used to extract quantitative measures from the resulting images. Autocorrelation analysis of the individually expressed variants reveals clustering of both variants, yet with differing properties. The cluster size is increased for α3L compared to α3K (mean radius 92 ± 4 and 56 ± 3 nm, respectively), yet an even bigger difference is found in the cluster density (9,870 ± 1,433 and 1,747 ± 200 μm(-2), respectively). Furthermore, cross-correlation analysis revealed that upon co-expression, clusters colocalize on the same spatial scales as for individually expressed receptors (mean co-cluster radius 94 ± 6 nm). These results demonstrate that RNA splicing determines GlyR α3 membrane distribution, which has consequences for neuronal GlyR physiology and function.
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Affiliation(s)
- Kristof Notelaers
- Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan Gebouw C, 3590, Diepenbeek, Belgium
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40
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Winkelmann A, Maggio N, Eller J, Caliskan G, Semtner M, Häussler U, Jüttner R, Dugladze T, Smolinsky B, Kowalczyk S, Chronowska E, Schwarz G, Rathjen FG, Rechavi G, Haas CA, Kulik A, Gloveli T, Heinemann U, Meier JC. Changes in neural network homeostasis trigger neuropsychiatric symptoms. J Clin Invest 2014; 124:696-711. [PMID: 24430185 PMCID: PMC3904623 DOI: 10.1172/jci71472] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 10/31/2013] [Indexed: 12/13/2022] Open
Abstract
The mechanisms that regulate the strength of synaptic transmission and intrinsic neuronal excitability are well characterized; however, the mechanisms that promote disease-causing neural network dysfunction are poorly defined. We generated mice with targeted neuron type-specific expression of a gain-of-function variant of the neurotransmitter receptor for glycine (GlyR) that is found in hippocampectomies from patients with temporal lobe epilepsy. In this mouse model, targeted expression of gain-of-function GlyR in terminals of glutamatergic cells or in parvalbumin-positive interneurons persistently altered neural network excitability. The increased network excitability associated with gain-of-function GlyR expression in glutamatergic neurons resulted in recurrent epileptiform discharge, which provoked cognitive dysfunction and memory deficits without affecting bidirectional synaptic plasticity. In contrast, decreased network excitability due to gain-of-function GlyR expression in parvalbumin-positive interneurons resulted in an anxiety phenotype, but did not affect cognitive performance or discriminative associative memory. Our animal model unveils neuron type-specific effects on cognition, formation of discriminative associative memory, and emotional behavior in vivo. Furthermore, our data identify a presynaptic disease-causing molecular mechanism that impairs homeostatic regulation of neural network excitability and triggers neuropsychiatric symptoms.
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Affiliation(s)
- Aline Winkelmann
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Nicola Maggio
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Joanna Eller
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Gürsel Caliskan
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Marcus Semtner
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Ute Häussler
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - René Jüttner
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Tamar Dugladze
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Birthe Smolinsky
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Sarah Kowalczyk
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Ewa Chronowska
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Günter Schwarz
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Fritz G. Rathjen
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Gideon Rechavi
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Carola A. Haas
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Akos Kulik
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Tengis Gloveli
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Uwe Heinemann
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
| | - Jochen C. Meier
- FU-Berlin, Fachbereich Biologie, Chemie, Pharmazie, Berlin, Germany.
RNA editing and Hyperexcitability Disorders Helmholtz Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Talpiot Medical Leadership Program, Department of Neurology and the J. Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel.
Cellular and Network Physiology Group, Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany.
CC2 Zentrum für Physiologie, Freie Universität Berlin, Berlin, Germany.
Experimental Epilepsy Research, Department of Neurosurgery, Neurocenter, University of Freiburg, Freiburg, Germany.
Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany.
Institute of Biochemistry, University of Cologne and Center for Molecular Medicine, Cologne, Germany.
Department of Physiology II, University of Freiburg, Freiburg, Germany.
Sheba Cancer Research Center, The Chaim Sheba Medical Center and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
BrainLinks-BrainTools, Cluster of Excellence and
BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany
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Glycine transporters as novel therapeutic targets in schizophrenia, alcohol dependence and pain. Nat Rev Drug Discov 2014; 12:866-85. [PMID: 24172334 DOI: 10.1038/nrd3893] [Citation(s) in RCA: 153] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glycine transporters are endogenous regulators of the dual functions of glycine, which acts as a classical inhibitory neurotransmitter at glycinergic synapses and as a modulator of neuronal excitation mediated by NMDA (N-methyl-D-aspartate) receptors at glutamatergic synapses. The two major subtypes of glycine transporters, GlyT1 and GlyT2, have been linked to the pathogenesis and/or treatment of central and peripheral nervous system disorders, including schizophrenia and related affective and cognitive disturbances, alcohol dependence, pain, epilepsy, breathing disorders and startle disease (also known as hyperekplexia). This Review examines the rationale for the therapeutic potential of GlyT1 and GlyT2 inhibition, and surveys the latest advances in the biology of glycine reuptake and transport as well as the drug discovery and clinical development of compounds that block glycine transporters.
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Förstera B, a Dzaye OD, Winkelmann A, Semtner M, Benedetti B, Markovic DS, Synowitz M, Wend P, Fähling M, Junier MP, Glass R, Kettenmann H, Meier JC. Intracellular glycine receptor function facilitates glioma formation in vivo. J Cell Sci 2014; 127:3687-98. [DOI: 10.1242/jcs.146662] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The neuronal function of Cys-loop neurotransmitter receptors is established; however, their role in non-neuronal cells is poorly defined. As brain tumors accumulate the neurotransmitter glycine, we studied expression and function of glycine receptors (GlyR) in glioma cells. Human brain tumor biopsies selectively expressed GlyR subunits with nuclear import signal (NLS, α1 and α3). The mouse glioma cell line GL261 expressed GlyR α1, and knock-down of α1 protein expression impaired self-renewal capacity and tumorigenicity of GL261 glioma cells as evidenced by the neurosphere assay and GL261 cell inoculation in vivo, respectively. We furthermore show that the pronounced tumorigenic effect of GlyR α1 relies on a new intracellular signaling function that depends on the NLS region in the large cytosolic loop and impacts on GL261 glioma cell gene regulation. Stable expression of GlyR α1 and α3 loops rescued self-renewal capacity of GlyR α1 knock-down cells, which demonstrates their functional equivalence. The new intracellular signaling function identified here goes beyond the well-established role of GlyRs as neuronal ligand-gated ion channels and defines NLS-containing GlyRs as novel potential targets for brain tumor therapies.
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Avila A, Nguyen L, Rigo JM. Glycine receptors and brain development. Front Cell Neurosci 2013; 7:184. [PMID: 24155690 PMCID: PMC3800850 DOI: 10.3389/fncel.2013.00184] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/01/2013] [Indexed: 12/21/2022] Open
Abstract
Glycine receptors (GlyRs) are ligand-gated chloride ion channels that mediate fast inhibitory neurotransmission in the spinal cord and the brainstem. There, they are mainly involved in motor control and pain perception in the adult. However, these receptors are also expressed in upper regions of the central nervous system, where they participate in different processes including synaptic neurotransmission. Moreover, GlyRs are present since early stages of brain development and might influence this process. Here, we discuss the current state of the art regarding GlyRs during embryonic and postnatal brain development in light of recent findings about the cellular and molecular mechanisms that control brain development.
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Affiliation(s)
- Ariel Avila
- Cell Physiology, BIOMED Research Institute, Hasselt University Diepenbeek, Belgium ; Groupe Interdisciplinaire Génoprotéomique Appliquée-Neurosciences, Centre Hospitalier Universitaire Sart Tilman, University of Liége Liège, Belgium ; Groupe Interdisciplinaire Génoprotéomique Appliquée-Research, Centre Hospitalier Universitaire Sart Tilman, University of Liège Liège, Belgium
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McCracken LM, Trudell JR, McCracken ML, Harris RA. Zinc-dependent modulation of α2- and α3-glycine receptor subunits by ethanol. Alcohol Clin Exp Res 2013; 37:2002-10. [PMID: 23895467 DOI: 10.1111/acer.12192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 04/09/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Strychnine-sensitive glycine receptors (GlyRs) are expressed throughout the brain and spinal cord and are among the strongly supported protein targets of alcohol. This is based largely on studies of the α1-subunit; however, α2- and α3-GlyR subunits are as or more abundantly expressed than α1-GlyRs in multiple forebrain brain areas considered to be important for alcohol-related behaviors, and uniquely some α3-GlyRs undergo RNA editing. Nanomolar and low micromolar concentrations of zinc ions potentiate GlyR function, and in addition to zinc's effects on glycine-activated currents, we have recently shown that physiological concentrations of zinc also enhance the magnitude of ethanol (EtOH)'s effects on α1-GlyRs. METHODS Using 2-electrode voltage-clamp electrophysiology in oocytes expressing either α2- or α3-GlyRs, we first tested the hypothesis that the effects of EtOH on α2- and α3-GlyRs would be zinc dependent, as we have previously reported for α1-GlyRs. Next, we constructed an α3P185L-mutant GlyR to test whether RNA-edited and unedited GlyRs contain differences in EtOH sensitivity. Last, we built a homology model of the α3-GlyR subunit. RESULTS The effects of EtOH (20 to 200 mM) on both subunits were greater in the presence than in the absence of 500 nM added zinc. The α3P185L-mutation that corresponds to RNA editing increased sensitivity to glycine and decreased sensitivity to EtOH. CONCLUSIONS Our findings provide further evidence that zinc is important for determining the magnitude of EtOH's effects at GlyRs and suggest that by better understanding zinc/EtOH interactions at GlyRs, we may better understand the sites and mechanisms of EtOH action.
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Affiliation(s)
- Lindsay M McCracken
- The Waggoner Center for Alcohol and Addiction Research , The University of Texas at Austin, Austin, Texas
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New insights in endogenous modulation of ligand-gated ion channels: histamine is an inverse agonist at strychnine sensitive glycine receptors. Eur J Pharmacol 2013; 710:59-66. [PMID: 23603522 DOI: 10.1016/j.ejphar.2013.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 03/28/2013] [Accepted: 04/03/2013] [Indexed: 01/18/2023]
Abstract
Histamine is involved in many physiological functions in the periphery and is an important neurotransmitter in the brain. It acts on metabotropic H1-H4 receptors mediating vasodilatation, bronchoconstriction and stimulation of gastric acid secretion. In the brain histamine is produced by neurons in the tuberomamillary nucleus (TMN), which controls arousal. Histamine is also a positive modulator of the inhibitory Cys-loop ligand-gated ion channel GABAA. We investigated now its effect on the second member of inhibitory Cys-loop ligand-gated ion channels, the strychnine sensitive glycine receptor. We expressed different human and rat glycine receptor subunits in Xenopus laevis oocytes and characterized the effect of histamine using the two electrode voltage clamp technique. Furthermore we investigated native glycine receptors in hypothalamic neurons using the patch-clamp technique. Histamine inhibited α1β glycine receptors with an IC50 of 5.2±0.3 mM. In presence of 10 mM histamine the glycine dose-response curve was shifted, increasing the EC50 for glycine from 25.5±1.4 μM to 42.4±2.3 μM. In addition, histamine blocked the spontaneous activity of RNA-edited α3β glycine receptors. Histamine inhibited glycine receptors expressed in hypothalamic TMN neurons with an IC50 of 4.6±0.3 mM. Our results give strong evidence that histamine is acting on the same binding site as glycine, being an inverse agonist that competitively antagonizes glycine receptors. Thus, we revealed histamine as an endogenous modulator of glycine receptors.
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Talwar S, Lynch JW, Gilbert DF. Fluorescence-based high-throughput functional profiling of ligand-gated ion channels at the level of single cells. PLoS One 2013; 8:e58479. [PMID: 23520514 PMCID: PMC3592791 DOI: 10.1371/journal.pone.0058479] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 02/06/2013] [Indexed: 12/26/2022] Open
Abstract
Ion channels are involved in many physiological processes and are attractive targets for therapeutic intervention. Their functional properties vary according to their subunit composition, which in turn varies in a developmental and tissue-specific manner and as a consequence of pathophysiological events. Understanding this diversity requires functional analysis of ion channel properties in large numbers of individual cells. Functional characterisation of ligand-gated channels involves quantitating agonist and drug dose-response relationships using electrophysiological or fluorescence-based techniques. Electrophysiology is limited by low throughput and high-throughput fluorescence-based functional evaluation generally does not enable the characterization of the functional properties of each individual cell. Here we describe a fluorescence-based assay that characterizes functional channel properties at single cell resolution in high throughput mode. It is based on progressive receptor activation and iterative fluorescence imaging and delivers >100 dose-responses in a single well of a 384-well plate, using α1-3 homomeric and αβ heteromeric glycine receptor (GlyR) chloride channels as a model system. We applied this assay with transiently transfected HEK293 cells co-expressing halide-sensitive yellow fluorescent protein and different GlyR subunit combinations. Glycine EC50 values of different GlyR isoforms were highly correlated with published electrophysiological data and confirm previously reported pharmacological profiles for the GlyR inhibitors, picrotoxin, strychnine and lindane. We show that inter and intra well variability is low and that clustering of functional phenotypes permits identification of drugs with subunit-specific pharmacological profiles. As this method dramatically improves the efficiency with which ion channel populations can be characterized in the context of cellular heterogeneity, it should facilitate systems-level analysis of ion channel properties in health and disease and the discovery of therapeutics to reverse pathological alterations.
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Affiliation(s)
- Sahil Talwar
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Joseph W. Lynch
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Daniel F. Gilbert
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
- * E-mail:
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Kowalczyk S, Winkelmann A, Smolinsky B, Förstera B, Neundorf I, Schwarz G, Meier JC. Direct binding of GABAA receptor β2 and β3 subunits to gephyrin. Eur J Neurosci 2012. [PMID: 23205938 DOI: 10.1111/ejn.12078] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
GABAergic transmission is essential to brain function, and a large repertoire of GABA type A receptor (GABA(A) R) subunits is at a neuron's disposition to serve this function. The glycine receptor (GlyR)-associated protein gephyrin has been shown to be essential for the clustering of a subset of GABA(A) R. Despite recent progress in the field of gephyrin-dependent mechanisms of postsynaptic GABA(A) R stabilisation, the role of gephyrin in synaptic GABA(A) R localisation has remained a complex matter with many open questions. Here, we analysed comparatively the interaction of purified rat gephyrin and mouse brain gephyrin with the large cytoplasmic loops of GABA(A) R α1, α2, β2 and β3 subunits. Binding affinities were determined using surface plasmon resonance spectroscopy, and showed an ~ 20-fold lower affinity of the β2 loop to gephyrin as compared to the GlyR β loop-gephyrin interaction. We also probed in vivo binding in primary cortical neurons by the well-established use of chimaeras of GlyR α1 that harbour respective gephyrin-binding motifs derived from the different GABA(A) R subunits. These studies identify a novel gephyrin-binding motif in GABA(A) R β2 and β3 large cytoplasmic loops.
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Affiliation(s)
- Sarah Kowalczyk
- Department of Chemistry, Institute of Biochemistry, University of Cologne, Cologne, Germany
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Notelaers K, Smisdom N, Rocha S, Janssen D, Meier JC, Rigo JM, Hofkens J, Ameloot M. Ensemble and single particle fluorimetric techniques in concerted action to study the diffusion and aggregation of the glycine receptor α3 isoforms in the cell plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:3131-40. [PMID: 22906711 DOI: 10.1016/j.bbamem.2012.08.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 08/03/2012] [Accepted: 08/11/2012] [Indexed: 10/28/2022]
Abstract
The spatio-temporal membrane behavior of glycine receptors (GlyRs) is known to be of influence on receptor homeostasis and functionality. In this work, an elaborate fluorimetric strategy was applied to study the GlyR α3K and L isoforms. Previously established differential clustering, desensitization and synaptic localization of these isoforms imply that membrane behavior is crucial in determining GlyR α3 physiology. Therefore diffusion and aggregation of homomeric α3 isoform-containing GlyRs were studied in HEK 293 cells. A unique combination of multiple diffraction-limited ensemble average methods and subdiffraction single particle techniques was used in order to achieve an integrated view of receptor properties. Static measurements of aggregation were performed with image correlation spectroscopy (ICS) and, single particle based, direct stochastic optical reconstruction microscopy (dSTORM). Receptor diffusion was measured by means of raster image correlation spectroscopy (RICS), temporal image correlation spectroscopy (TICS), fluorescence recovery after photobleaching (FRAP) and single particle tracking (SPT). The results show a significant difference in diffusion coefficient and cluster size between the isoforms. This reveals a positive correlation between desensitization and diffusion and disproves the notion that receptor aggregation is a universal mechanism for accelerated desensitization. The difference in diffusion coefficient between the clustering GlyR α3L and the non-clustering GlyR α3K cannot be explained by normal diffusion. SPT measurements indicate that the α3L receptors undergo transient trapping and directed motion, while the GlyR α3K displays mild hindered diffusion. These findings are suggestive of differential molecular interaction of the isoforms after incorporation in the membrane.
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Affiliation(s)
- Kristof Notelaers
- Biomedical Research Institute, Hasselt University and School of Life Sciences, Transnational University Limburg, Agoralaan gebouw C, 3590 Diepenbeek, Belgium
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Wang L, Li WG, Huang C, Zhu MX, Xu TL, Wu DZ, Li Y. Subunit-specific inhibition of glycine receptors by curcumol. J Pharmacol Exp Ther 2012; 343:371-9. [PMID: 22892339 DOI: 10.1124/jpet.112.195669] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Emerging evidence has suggested that inhibitory glycine receptors (GlyRs) are an important molecular target in the treatment of numerous neurological disorders. Rhizoma curcumae is a medicinal plant with positive neurological effects. In this study, we showed that curcumol, a major bioactive component of R. curcumae, reversibly and concentration-dependently inhibited the glycine-activated current (IGly) in cultured rat hippocampal neurons. The inhibitory effect was neither voltage- nor agonist concentration-dependent. Moreover, curcumol selectively inhibited homomeric α2-containing, but not α1- or α3-containing, GlyRs. The addition of β subunit conferred the curcumol sensitivity of α3-containing, but not α1-containing, GlyRs. Site-directed mutagenesis analysis revealed that a threonine at position 59 of the α2 subunit is critical for the susceptibility of GlyRs to curcumol-mediated inhibition. Furthermore, paralleling a decline of α2 subunit expression during spinal cord development, the degree of IGly inhibition by curcumol decreased with prolonged culture of rat spinal dorsal horn neurons. Taken together, our results suggest that the GlyRs are novel molecular targets of curcumol, which may underlie its pharmaceutical effects in the central nervous system.
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Affiliation(s)
- Li Wang
- Institute of Chinese Materia Medica, Shanghai Key Laboratory of Complex Prescription, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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Lynagh T, Lynch JW. Molecular mechanisms of Cys-loop ion channel receptor modulation by ivermectin. Front Mol Neurosci 2012; 5:60. [PMID: 22586367 PMCID: PMC3345530 DOI: 10.3389/fnmol.2012.00060] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 04/17/2012] [Indexed: 11/13/2022] Open
Abstract
Ivermectin is an anthelmintic drug that works by inhibiting neuronal activity and muscular contractility in arthropods and nematodes. It works by activating glutamate-gated chloride channels (GluClRs) at nanomolar concentrations. These receptors, found exclusively in invertebrates, belong to the pentameric Cys-loop receptor family of ligand-gated ion channels (LGICs). Higher (micromolar) concentrations of ivermectin also activate or modulate vertebrate Cys-loop receptors, including the excitatory nicotinic and the inhibitory GABA type-A and glycine receptors (GlyRs). An X-ray crystal structure of ivermectin complexed with the C. elegans α GluClR demonstrated that ivermectin binds to the transmembrane domain in a cleft at the interface of adjacent subunits. It also identified three hydrogen bonds thought to attach ivermectin to its site. Site-directed mutagenesis and voltage-clamp electrophysiology have also been employed to probe the binding site for ivermectin in α1 GlyRs. These have raised doubts as to whether the hydrogen bonds are essential for high ivermectin potency. Due to its lipophilic nature, it is likely that ivermectin accumulates in the membrane and binds reversibly (i.e., weakly) to its site. Several lines of evidence suggest that ivermectin opens the channel pore via a structural change distinct from that induced by the neurotransmitter agonist. Conformational changes occurring at locations distant from the pore can be probed using voltage-clamp fluorometry (VCF), a technique which involves quantitating agonist-induced fluorescence changes from environmentally sensitive fluorophores covalently attached to receptor domains of interest. This technique has demonstrated that ivermectin induces a global conformational change that propagates from the transmembrane domain to the neurotransmitter binding site, thus suggesting a mechanism by which ivermectin potentiates neurotransmitter-gated currents. Together, this information provides new insights into the mechanisms of action of this important drug.
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Affiliation(s)
- Timothy Lynagh
- Queensland Brain Institute, The University of Queensland, Brisbane QLD, Australia
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