1
|
Neumann E, Cramer T, Acuña MA, Scheurer L, Beccarini C, Luscher B, Wildner H, Zeilhofer HU. γ1 GABA A Receptors in Spinal Nociceptive Circuits. J Neurosci 2024; 44:e0591242024. [PMID: 39137998 PMCID: PMC11466064 DOI: 10.1523/jneurosci.0591-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 07/17/2024] [Accepted: 08/02/2024] [Indexed: 08/15/2024] Open
Abstract
GABAergic neurons and GABAA receptors (GABAARs) are critical elements of almost all neuronal circuits. Most GABAARs of the CNS are heteropentameric ion channels composed of two α, two β, and one γ subunits. These receptors serve as important drug targets for benzodiazepine (BDZ) site agonists, which potentiate the action of GABA at GABAARs. Most GABAAR classifications rely on the heterogeneity of the α subunit (α1-α6) included in the receptor complex. Heterogeneity of the γ subunits (γ1-γ3), which mediate synaptic clustering of GABAARs and contribute, together with α subunits, to the benzodiazepine (BDZ) binding site, has gained less attention, mainly because γ2 subunits greatly outnumber the other γ subunits in most brain regions. Here, we have investigated a potential role of non-γ2 GABAARs in neural circuits of the spinal dorsal horn, a key site of nociceptive processing. Female and male mice were studied. We demonstrate that besides γ2 subunits, γ1 subunits are significantly expressed in the spinal dorsal horn, especially in its superficial layers. Unlike global γ2 subunit deletion, which is lethal, spinal cord-specific loss of γ2 subunits was well tolerated. GABAAR clustering in the superficial dorsal horn remained largely unaffected and antihyperalgesic actions of HZ-166, a nonsedative BDZ site agonist, were partially retained. Our results thus suggest that the superficial dorsal horn harbors functionally relevant amounts of γ1 subunits that support the synaptic clustering of GABAARs in this site. They further suggest that γ1 containing GABAARs contribute to the spinal control of nociceptive information flow.
Collapse
Affiliation(s)
- Elena Neumann
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Teresa Cramer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Mario A Acuña
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Louis Scheurer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Camilla Beccarini
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Bernhard Luscher
- Departments of Biology, Biochemistry and Molecular Biology, and Psychiatry and Penn State Neuroscience Institute, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, CH-8093 Zurich, Switzerland
| |
Collapse
|
2
|
Dunham TL, Wilkerson JR, Johnson RC, Huganir RL, Volk LJ. WWC2 modulates GABA A-receptor-mediated synaptic transmission, revealing class-specific mechanisms of synapse regulation by WWC family proteins. Cell Rep 2024; 43:114841. [PMID: 39388350 DOI: 10.1016/j.celrep.2024.114841] [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: 08/03/2023] [Revised: 07/22/2024] [Accepted: 09/21/2024] [Indexed: 10/12/2024] Open
Abstract
The WW and C2 domain-containing protein (WWC2) is implicated in several neurological disorders. Here, we demonstrate that WWC2 interacts with inhibitory, but not excitatory, postsynaptic scaffolds, consistent with prior proteomic identification of WWC2 as a putative component of the inhibitory postsynaptic density. Using mice lacking WWC2 expression in excitatory forebrain neurons, we show that WWC2 suppresses γ-aminobutyric acid type-A receptor (GABAAR) incorporation into the plasma membrane and regulates HAP1 and GRIP1, which form a complex promoting GABAAR recycling to the membrane. Inhibitory synaptic transmission is increased in CA1 pyramidal cells lacking WWC2. Furthermore, unlike the WWC2 homolog KIBRA (kidney/brain protein; WWC1), a key regulator of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) trafficking at excitatory synapses, the deletion of WWC2 does not affect synaptic AMPAR expression. In contrast, loss of KIBRA does not affect GABAAR membrane expression. These data reveal synapse class-selective functions for WWC proteins as regulators of ionotropic neurotransmitter receptors and provide insight into mechanisms regulating GABAAR membrane expression.
Collapse
Affiliation(s)
- Thomas L Dunham
- Neuroscience Graduate Program, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Julia R Wilkerson
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Richard C Johnson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Richard L Huganir
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lenora J Volk
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Psychiatry UT Southwestern Medical Center, Dallas, TX 75390, USA; Peter O'Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
3
|
Kan C, Ullah A, Dang S, Xue H. Modular Structure and Polymerization Status of GABA A Receptors Illustrated with EM Analysis and AlphaFold2 Prediction. Int J Mol Sci 2024; 25:10142. [PMID: 39337627 PMCID: PMC11432007 DOI: 10.3390/ijms251810142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2024] [Revised: 08/31/2024] [Accepted: 09/18/2024] [Indexed: 09/30/2024] Open
Abstract
Type-A γ-aminobutyric acid (GABAA) receptors are channel proteins crucial to mediating neuronal balance in the central nervous system (CNS). The structure of GABAA receptors allows for multiple binding sites and is key to drug development. Yet the formation mechanism of the receptor's distinctive pentameric structure is still unknown. This study aims to investigate the role of three predominant subunits of the human GABAA receptor in the formation of protein pentamers. Through purifying and refolding the protein fragments of the GABAA receptor α1, β2, and γ2 subunits, the particle structures were visualised with negative staining electron microscopy (EM). To aid the analysis, AlphaFold2 was used to compare the structures. Results show that α1 and β2 subunit fragments successfully formed homo-oligomers, particularly homopentameric structures, while the predominant heteropentameric GABAA receptor was also replicated through the combination of the three subunits. However, homopentameric structures were not observed with the γ2 subunit proteins. A comparison of the AlphaFold2 predictions and the previously obtained cryo-EM structures presents new insights into the subunits' modular structure and polymerization status. By performing experimental and computational studies, a deeper understanding of the complex structure of GABAA receptors is provided. Hopefully, this study can pave the way to developing novel therapeutics for neuropsychiatric diseases.
Collapse
Affiliation(s)
| | | | | | - Hong Xue
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China; (C.K.); (A.U.); (S.D.)
| |
Collapse
|
4
|
Yoon SH, Song WS, Chung G, Kim SJ, Kim MH. Activity in the dorsal hippocampus-mPFC circuit modulates stress-coping strategies during inescapable stress. Exp Mol Med 2024; 56:1921-1935. [PMID: 39218973 PMCID: PMC11447212 DOI: 10.1038/s12276-024-01294-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 05/20/2024] [Accepted: 06/06/2024] [Indexed: 09/04/2024] Open
Abstract
Anatomical connectivity and lesion-deficit studies have shown that the dorsal and ventral hippocampi contribute to cognitive and emotional processes, respectively. However, the role of the dorsal hippocampus (dHP) in emotional or stress-related behaviors remains unclear. Here, we showed that neuronal activity in the dHP affects stress-coping behaviors in mice via excitatory projections to the medial prefrontal cortex (mPFC). The antidepressant ketamine rapidly induced c-Fos expression in both the dorsal and ventral hippocampi. The suppression of GABAergic transmission in the dHP-induced molecular changes similar to those induced by ketamine administration, including eukaryotic elongation factor 2 (eEF2) dephosphorylation, brain-derived neurotrophic factor (BDNF) elevation, and extracellular signal-regulated kinase (ERK) phosphorylation. These synaptic and molecular changes in the dHP induced a reduction in the immobility time of the mice in the tail-suspension and forced swim tests without affecting anxiety-related behavior. Conversely, pharmacological and chemogenetic potentiation of inhibitory neurotransmission in the dHP CA1 region induced passive coping behaviors during the tests. Transneuronal tracing and electrophysiology revealed monosynaptic excitatory connections between dHP CA1 neurons and mPFC neurons. Optogenetic stimulation of dHP CA1 neurons in freely behaving mice produced c-Fos induction and spike firing in the mPFC neurons. Chemogenetic activation of the dHP-recipient mPFC neurons reversed the passive coping behaviors induced by suppression of dHP CA1 neuronal activity. Collectively, these results indicate that neuronal activity in the dHP modulates stress-coping strategies to inescapable stress and contributes to the antidepressant effects of ketamine via the dHP-mPFC circuit.
Collapse
Affiliation(s)
- Sang Ho Yoon
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, 03080, Korea
- Department of Anatomy & Neurobiology, University of California Irvine, Irvine, CA, 92697, USA
| | - Woo Seok Song
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, 03080, Korea
| | - Geehoon Chung
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, 03080, Korea
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, 02447, Korea
| | - Sang Jeong Kim
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea
- Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, 03080, Korea
| | - Myoung-Hwan Kim
- Department of Physiology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Korea.
- Neuroscience Research Institute, Seoul National University Medical Research Center, Seoul, 03080, Korea.
- Seoul National University Bundang Hospital, Seongnam, Gyeonggi, 13620, Korea.
| |
Collapse
|
5
|
Correa E, Mialon M, Cizeron M, Bessereau JL, Pinan-Lucarre B, Kratsios P. UNC-30/PITX coordinates neurotransmitter identity with postsynaptic GABA receptor clustering. Development 2024; 151:dev202733. [PMID: 39190555 PMCID: PMC11385328 DOI: 10.1242/dev.202733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 07/10/2024] [Indexed: 08/29/2024]
Abstract
Terminal selectors are transcription factors that control neuronal identity by regulating expression of key effector molecules, such as neurotransmitter biosynthesis proteins and ion channels. Whether and how terminal selectors control neuronal connectivity is poorly understood. Here, we report that UNC-30 (PITX2/3), the terminal selector of GABA nerve cord motor neurons in Caenorhabditis elegans, is required for neurotransmitter receptor clustering, a hallmark of postsynaptic differentiation. Animals lacking unc-30 or madd-4B, the short isoform of the motor neuron-secreted synapse organizer madd-4 (punctin/ADAMTSL), display severe GABA receptor type A (GABAAR) clustering defects in postsynaptic muscle cells. Mechanistically, UNC-30 acts directly to induce and maintain transcription of madd-4B and GABA biosynthesis genes (e.g. unc-25/GAD, unc-47/VGAT). Hence, UNC-30 controls GABAA receptor clustering in postsynaptic muscle cells and GABA biosynthesis in presynaptic cells, transcriptionally coordinating two crucial processes for GABA neurotransmission. Further, we uncover multiple target genes and a dual role for UNC-30 as both an activator and a repressor of gene transcription. Our findings on UNC-30 function may contribute to our molecular understanding of human conditions, such as Axenfeld-Rieger syndrome, caused by PITX2 and PITX3 gene variants.
Collapse
Affiliation(s)
- Edgar Correa
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
- Committee on Cell and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Morgane Mialon
- Melis, Universite Claude Bernard Lyon 1, CNRS UMR5284, INSERM U1314, Institut NeuroMyoGene - Faculte de Medecine et de Pharmacie, 69008 Lyon, France
| | - Mélissa Cizeron
- Melis, Universite Claude Bernard Lyon 1, CNRS UMR5284, INSERM U1314, Institut NeuroMyoGene - Faculte de Medecine et de Pharmacie, 69008 Lyon, France
| | - Jean-Louis Bessereau
- Melis, Universite Claude Bernard Lyon 1, CNRS UMR5284, INSERM U1314, Institut NeuroMyoGene - Faculte de Medecine et de Pharmacie, 69008 Lyon, France
| | - Berangere Pinan-Lucarre
- Melis, Universite Claude Bernard Lyon 1, CNRS UMR5284, INSERM U1314, Institut NeuroMyoGene - Faculte de Medecine et de Pharmacie, 69008 Lyon, France
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
- Committee on Cell and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
- University of Chicago Neuroscience Institute, Chicago, IL 60637, USA
| |
Collapse
|
6
|
Alpay B, Cimen B, Akaydin E, Onat F, Bolay H, Sara Y. Extrasynaptic δGABAA receptors mediate resistance to migraine-like phenotype in rats. J Headache Pain 2024; 25:75. [PMID: 38724972 PMCID: PMC11083752 DOI: 10.1186/s10194-024-01777-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/22/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND GABA, a key inhibitory neurotransmitter, has synaptic and extrasynaptic receptors on the postsynaptic neuron. Background GABA, which spills over from the synaptic cleft, acts on extrasynaptic delta subunit containing GABAA receptors. The role of extrasynaptic GABAergic input in migraine is unknown. We investigated the susceptibility to valid migraine-provoking substances with clinically relevant behavioral readouts in Genetic Absence Epilepsy of Rats Strasbourg (GAERS), in which the GABAergic tonus was altered. Subsequently, we screened relevant GABAergic mechanisms in Wistar rats by pharmacological means to identify the mechanisms. METHODS Wistar and GAERS rats were administered nitroglycerin (10 mg/kg) or levcromakalim (1 mg/kg). Mechanical allodynia and photophobia were assessed using von Frey monofilaments and a dark-light box. Effects of GAT-1 blocker tiagabine (5 mg/kg), GABAB receptor agonist baclofen (2 mg/kg), synaptic GABAA receptor agonist diazepam (1 mg/kg), extrasynaptic GABAA receptor agonists gaboxadol (4 mg/kg), and muscimol (0.75 mg/kg), T-type calcium channel blocker ethosuximide (100 mg/kg) or synaptic GABAA receptor antagonist flumazenil (15 mg/kg) on levcromakalim-induced migraine phenotype were screened. RESULTS Unlike Wistar rats, GAERS exhibited no reduction in mechanical pain thresholds or light aversion following nitroglycerin or levcromakalim injection. Ethosuximide did not reverse the resistant phenotype in GAERS, excluding the role of T-type calcium channel dysfunction in this phenomenon. Tiagabine prevented levcromakalim-induced mechanical allodynia in Wistar rats, suggesting a key role in enhanced GABA spillover. Baclofen did not alleviate mechanical allodynia. Diazepam failed to mitigate levcromakalim-induced migraine phenotype. Additionally, the resistant phenotype in GAERS was not affected by flumazenil. Extrasynaptic GABAA receptor agonists gaboxadol and muscimol inhibited periorbital allodynia in Wistar rats. CONCLUSION Our study introduced a rat strain resistant to migraine-provoking agents and signified a critical involvement of extrasynaptic δGABAergic receptors. Extrasynaptic δ GABAA receptors, by mediating constant background inhibition on the excitability of neurons, stand as a novel drug target with a therapeutic potential in migraine.
Collapse
Affiliation(s)
- Berkay Alpay
- Department of Medical Pharmacology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, 06320, Türkiye
- Neuroscience and Neurotechnology Excellence Joint Application and Research Center (NÖROM), Ankara, 06560, Türkiye
| | - Bariscan Cimen
- Department of Medical Pharmacology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, 06320, Türkiye
- Neuroscience and Neurotechnology Excellence Joint Application and Research Center (NÖROM), Ankara, 06560, Türkiye
| | - Elif Akaydin
- Department of Medical Pharmacology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, 06320, Türkiye
- Neuroscience and Neurotechnology Excellence Joint Application and Research Center (NÖROM), Ankara, 06560, Türkiye
| | - Filiz Onat
- Department of Medical Pharmacology, Faculty of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, 34752, Türkiye
| | - Hayrunnisa Bolay
- Neuroscience and Neurotechnology Excellence Joint Application and Research Center (NÖROM), Ankara, 06560, Türkiye.
- Department of Neurology and Algology, Faculty of Medicine, Gazi University, Besevler, Ankara, 06560, Türkiye.
| | - Yildirim Sara
- Department of Medical Pharmacology, Faculty of Medicine, Hacettepe University, Sihhiye, Ankara, 06320, Türkiye.
- Neuroscience and Neurotechnology Excellence Joint Application and Research Center (NÖROM), Ankara, 06560, Türkiye.
| |
Collapse
|
7
|
Yuan Z, Pavel MA, Hansen SB. GABA and astrocytic cholesterol determine the lipid environment of GABA AR in cultured cortical neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591395. [PMID: 38746110 PMCID: PMC11092523 DOI: 10.1101/2024.04.26.591395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The γ-aminobutyric acid (GABA) type A receptor (GABAAR), a GABA activated pentameric chloride channel, mediates fast inhibitory neurotransmission in the brain. The lipid environment is critical for GABAAR function. How lipids regulate the channel in the cell membrane is not fully understood. Here we employed super resolution imaging of lipids to demonstrate that the agonist GABA induces a rapid and reversible membrane translocation of GABAAR to phosphatidylinositol 4,5-bisphosphate (PIP2) clusters in mouse primary cortical neurons. This translocation relies on nanoscopic separation of PIP2 clusters and lipid rafts (cholesterol-dependent ganglioside clusters). In a resting state, the GABAAR associates with lipid rafts and this colocalization is enhanced by uptake of astrocytic secretions. These astrocytic secretions enhance endocytosis and delay desensitization. Our findings suggest intercellular signaling from astrocytes regulates GABAAR location based on lipid uptake in neurons. The findings have implications for treating mood disorders associated with altered neural excitability.
Collapse
Affiliation(s)
- Zixuan Yuan
- Department of Molecular Medicine, Department of Neuroscience, The Scripps Research Institute, Scripps, Jupiter, Florida 33458, USA
- Scripps Research Skaggs Graduate School of Chemical and Biological Science, The Scripps Research Institute, Scripps, Jupiter, Florida 33458, USA
| | - Mahmud Arif Pavel
- Department of Molecular Medicine, Department of Neuroscience, The Scripps Research Institute, Scripps, Jupiter, Florida 33458, USA
| | - Scott B. Hansen
- Department of Molecular Medicine, Department of Neuroscience, The Scripps Research Institute, Scripps, Jupiter, Florida 33458, USA
- Scripps Research Skaggs Graduate School of Chemical and Biological Science, The Scripps Research Institute, Scripps, Jupiter, Florida 33458, USA
- Department of Molecular Medicine, Department of Neuroscience, UF Scripps, Jupiter, Florida 33458, USA
| |
Collapse
|
8
|
Dunham TL, Wilkerson JR, Johnson RC, Huganir RL, Volk LJ. Modulation of GABA A receptor trafficking by WWC2 reveals class-specific mechanisms of synapse regulation by WWC family proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584487. [PMID: 38559047 PMCID: PMC10979870 DOI: 10.1101/2024.03.11.584487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
WWC2 (WW and C2 domain-containing protein) is implicated in several neurological disorders, however its function in the brain has yet to be determined. Here, we demonstrate that WWC2 interacts with inhibitory but not excitatory postsynaptic scaffolds, consistent with prior proteomic identification of WWC2 as a putative component of the inhibitory postsynaptic density. Using mice lacking WWC2 expression in excitatory forebrain neurons, we show that WWC2 suppresses GABA A R incorporation into the plasma membrane and regulates HAP1 and GRIP1, which form a complex promoting GABA A R recycling to the membrane. Inhibitory synaptic transmission is dysregulated in CA1 pyramidal cells lacking WWC2. Furthermore, unlike the WWC2 homolog KIBRA (WWC1), a key regulator of AMPA receptor trafficking at excitatory synapses, deletion of WWC2 does not affect synaptic AMPAR expression. In contrast, loss of KIBRA does not affect GABA A R membrane expression. These data reveal unique, synapse class-selective functions for WWC proteins as regulators of ionotropic neurotransmitter receptors and provide insight into mechanisms regulating GABA A R membrane expression.
Collapse
|
9
|
Correa E, Mialon M, Cizeron M, Bessereau JL, Pinan-Lucarre B, Kratsios P. UNC-30/PITX coordinates neurotransmitter identity with postsynaptic GABA receptor clustering. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.14.580278. [PMID: 38405977 PMCID: PMC10888783 DOI: 10.1101/2024.02.14.580278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Terminal selectors are transcription factors that control neuronal identity by regulating the expression of key effector molecules, such as neurotransmitter (NT) biosynthesis proteins, ion channels and neuropeptides. Whether and how terminal selectors control neuronal connectivity is poorly understood. Here, we report that UNC-30 (PITX2/3), the terminal selector of GABA motor neuron identity in C. elegans , is required for NT receptor clustering, a hallmark of postsynaptic differentiation. Animals lacking unc-30 or madd-4B, the short isoform of the MN-secreted synapse organizer madd-4 ( Punctin/ADAMTSL ), display severe GABA receptor type A (GABA A R) clustering defects in postsynaptic muscle cells. Mechanistically, UNC-30 acts directly to induce and maintain transcription of madd-4B and GABA biosynthesis genes (e.g., unc-25/GAD , unc-47/VGAT ). Hence, UNC-30 controls GABA A R clustering on postsynaptic muscle cells and GABA biosynthesis in presynaptic cells, transcriptionally coordinating two critical processes for GABA neurotransmission. Further, we uncover multiple target genes and a dual role for UNC-30 both as an activator and repressor of gene transcription. Our findings on UNC-30 function may contribute to our molecular understanding of human conditions, such as Axenfeld-Rieger syndrome, caused by PITX2 and PITX3 gene mutations.
Collapse
|
10
|
Goldberg AR, Dovas A, Torres D, Sharma SD, Mela A, Merricks EM, Olabarria M, Shokooh LA, Zhao HT, Kotidis C, Calvaresi P, Viswanathan A, Banu MA, Razavilar A, Sudhakar TD, Saxena A, Chokran C, Humala N, Mahajan A, Xu W, Metz JB, Chen C, Bushong EA, Boassa D, Ellisman MH, Hillman EMC, McKhann GM, Gill BJA, Rosenfeld SS, Schevon CA, Bruce JN, Sims PA, Peterka DS, Canoll P. Glioma-Induced Alterations in Excitatory Neurons are Reversed by mTOR Inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.575092. [PMID: 38293120 PMCID: PMC10827113 DOI: 10.1101/2024.01.10.575092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Gliomas are highly aggressive brain tumors characterized by poor prognosis and composed of diffusely infiltrating tumor cells that intermingle with non-neoplastic cells in the tumor microenvironment, including neurons. Neurons are increasingly appreciated as important reactive components of the glioma microenvironment, due to their role in causing hallmark glioma symptoms, such as cognitive deficits and seizures, as well as their potential ability to drive glioma progression. Separately, mTOR signaling has been shown to have pleiotropic effects in the brain tumor microenvironment, including regulation of neuronal hyperexcitability. However, the local cellular-level effects of mTOR inhibition on glioma-induced neuronal alterations are not well understood. Here we employed neuron-specific profiling of ribosome-bound mRNA via 'RiboTag,' morphometric analysis of dendritic spines, and in vivo calcium imaging, along with pharmacological mTOR inhibition to investigate the impact of glioma burden and mTOR inhibition on these neuronal alterations. The RiboTag analysis of tumor-associated excitatory neurons showed a downregulation of transcripts encoding excitatory and inhibitory postsynaptic proteins and dendritic spine development, and an upregulation of transcripts encoding cytoskeletal proteins involved in dendritic spine turnover. Light and electron microscopy of tumor-associated excitatory neurons demonstrated marked decreases in dendritic spine density. In vivo two-photon calcium imaging in tumor-associated excitatory neurons revealed progressive alterations in neuronal activity, both at the population and single-neuron level, throughout tumor growth. This in vivo calcium imaging also revealed altered stimulus-evoked somatic calcium events, with changes in event rate, size, and temporal alignment to stimulus, which was most pronounced in neurons with high-tumor burden. A single acute dose of AZD8055, a combined mTORC1/2 inhibitor, reversed the glioma-induced alterations on the excitatory neurons, including the alterations in ribosome-bound transcripts, dendritic spine density, and stimulus evoked responses seen by calcium imaging. These results point to mTOR-driven pathological plasticity in neurons at the infiltrative margin of glioma - manifested by alterations in ribosome-bound mRNA, dendritic spine density, and stimulus-evoked neuronal activity. Collectively, our work identifies the pathological changes that tumor-associated excitatory neurons experience as both hyperlocal and reversible under the influence of mTOR inhibition, providing a foundation for developing therapies targeting neuronal signaling in glioma.
Collapse
Affiliation(s)
- Alexander R Goldberg
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Athanassios Dovas
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Daniela Torres
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Sohani Das Sharma
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY 10032
| | - Angeliki Mela
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Edward M Merricks
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Markel Olabarria
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | | | - Hanzhi T Zhao
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Corina Kotidis
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Peter Calvaresi
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ashwin Viswanathan
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Matei A Banu
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Aida Razavilar
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Tejaswi D Sudhakar
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Ankita Saxena
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Cole Chokran
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Nelson Humala
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Aayushi Mahajan
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Weihao Xu
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Jordan B Metz
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY 10032
| | - Cady Chen
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Eric A Bushong
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - Daniela Boassa
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Zuckerman Mind Brain Behavior Institute, Departments of Biomedical Engineering and Radiology, Columbia University, New York, NY 10027, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Brian J A Gill
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | | | - Catherine A Schevon
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Jeffrey N Bruce
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Peter A Sims
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY 10032
- Sulzberger Columbia Genome Center, Columbia University Irving Medical Center, New York, NY, 10032
- Department of Biochemistry & Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, 10032
| | - Darcy S Peterka
- Irving Institute for Cancer Dynamics, Columbia University, New York, NY 10027, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Irving Cancer Research Center, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Neurological Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| |
Collapse
|
11
|
Maguire JL, Mennerick S. Neurosteroids: mechanistic considerations and clinical prospects. Neuropsychopharmacology 2024; 49:73-82. [PMID: 37369775 PMCID: PMC10700537 DOI: 10.1038/s41386-023-01626-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/15/2023] [Accepted: 05/17/2023] [Indexed: 06/29/2023]
Abstract
Like other classes of treatments described in this issue's section, neuroactive steroids have been studied for decades but have risen as a new class of rapid-acting, durable antidepressants with a distinct mechanism of action from previous antidepressant treatments and from other compounds covered in this issue. Neuroactive steroids are natural derivatives of progesterone but are proving effective as exogenous treatments. The best understood mechanism is that of positive allosteric modulation of GABAA receptors, where subunit selectivity may promote their profile of action. Mechanistically, there is some reason to think that neuroactive steroids may separate themselves from liabilities of other GABA modulators, although research is ongoing. It is also possible that intracellular targets, including inflammatory pathways, may be relevant to beneficial actions. Strengths and opportunities for further development include exploiting non-GABAergic targets, structural analogs, enzymatic production of natural steroids, precursor loading, and novel formulations. The molecular mechanisms of behavioral effects are not fully understood, but study of brain network states involved in emotional processing demonstrate a robust influence on affective states not evident with at least some other GABAergic drugs including benzodiazepines. Ongoing studies with neuroactive steroids will further elucidate the brain and behavioral effects of these compounds as well as likely underpinnings of disease.
Collapse
Affiliation(s)
- Jamie L Maguire
- Department of Neuroscience, Tufts University School of Medicine, 136 Harrison Ave, Boston, MA, 02111, USA
| | - Steven Mennerick
- Department of Psychiatry and Taylor Family Institute for Innovative Psychiatric Research, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., St. Louis, MO, 63110, USA.
| |
Collapse
|
12
|
Olah SS, Kareemo DJ, Buchta WC, Sinnen BL, Miller CN, Actor-Engel HS, Gookin SE, Winborn CS, Kleinjan MS, Crosby KC, Aoto J, Smith KR, Kennedy MJ. Acute reorganization of postsynaptic GABA A receptors reveals the functional impact of molecular nanoarchitecture at inhibitory synapses. Cell Rep 2023; 42:113331. [PMID: 37910506 PMCID: PMC10782565 DOI: 10.1016/j.celrep.2023.113331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 09/01/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023] Open
Abstract
Neurotransmitter receptors partition into nanometer-scale subdomains within the postsynaptic membrane that are precisely aligned with presynaptic neurotransmitter release sites. While spatial coordination between pre- and postsynaptic elements is observed at both excitatory and inhibitory synapses, the functional significance of this molecular architecture has been challenging to evaluate experimentally. Here we utilized an optogenetic clustering approach to acutely alter the nanoscale organization of the postsynaptic inhibitory scaffold gephyrin while monitoring synaptic function. Gephyrin clustering rapidly enlarged postsynaptic area, laterally displacing GABAA receptors from their normally precise apposition with presynaptic active zones. Receptor displacement was accompanied by decreased synaptic GABAA receptor currents even though presynaptic release probability and the overall abundance and function of synaptic GABAA receptors remained unperturbed. Thus, acutely repositioning neurotransmitter receptors within the postsynaptic membrane profoundly influences synaptic efficacy, establishing the functional importance of precision pre-/postsynaptic molecular coordination at inhibitory synapses.
Collapse
Affiliation(s)
- Samantha S Olah
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Dean J Kareemo
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - William C Buchta
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Brooke L Sinnen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Carley N Miller
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Hannah S Actor-Engel
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Sara E Gookin
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Christina S Winborn
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mason S Kleinjan
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kevin C Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jason Aoto
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| |
Collapse
|
13
|
Garcia JD, Wolfe SE, Stewart AR, Tiemeier E, Gookin SE, Guerrero MB, Quillinan N, Smith KR. Distinct mechanisms drive sequential internalization and degradation of GABA ARs during global ischemia and reperfusion injury. iScience 2023; 26:108061. [PMID: 37860758 PMCID: PMC10582478 DOI: 10.1016/j.isci.2023.108061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/30/2023] [Accepted: 09/22/2023] [Indexed: 10/21/2023] Open
Abstract
Synaptic inhibition is critical for controlling neuronal excitability and function. During global cerebral ischemia (GCI), inhibitory synapses are rapidly eliminated, causing hyper-excitability which contributes to cell-death and the pathophysiology of disease. Sequential disassembly of inhibitory synapses begins within minutes of ischemia onset: GABAARs are rapidly trafficked away from the synapse, the gephyrin scaffold is removed, followed by loss of the presynaptic terminal. GABAARs are endocytosed during GCI, but how this process accompanies synapse disassembly remains unclear. Here, we define the precise trafficking itinerary of GABAARs during the initial stages of GCI, placing them in the context of rapid synapse elimination. Ischemia-induced GABAAR internalization quickly follows their initial dispersal from the synapse, and is controlled by PP1α signaling. During reperfusion injury, GABAARs are then trafficked to lysosomes for degradation, leading to permanent removal of synaptic GABAARs and contributing to the profound reduction in synaptic inhibition observed hours following ischemia onset.
Collapse
Affiliation(s)
- Joshua D. Garcia
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Sarah E. Wolfe
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Amber R. Stewart
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Erika Tiemeier
- Department of Anesthesiology, Neuronal Injury Program, University of Colorado School of Medicine, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Sara E. Gookin
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Mayra Bueno Guerrero
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Nidia Quillinan
- Department of Anesthesiology, Neuronal Injury Program, University of Colorado School of Medicine, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Katharine R. Smith
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| |
Collapse
|
14
|
Tagore M, Hergenreder E, Perlee SC, Cruz NM, Menocal L, Suresh S, Chan E, Baron M, Melendez S, Dave A, Chatila WK, Nsengimana J, Koche RP, Hollmann TJ, Ideker T, Studer L, Schietinger A, White RM. GABA Regulates Electrical Activity and Tumor Initiation in Melanoma. Cancer Discov 2023; 13:2270-2291. [PMID: 37553760 PMCID: PMC10551668 DOI: 10.1158/2159-8290.cd-23-0389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/27/2023] [Accepted: 08/02/2023] [Indexed: 08/10/2023]
Abstract
Oncogenes can initiate tumors only in certain cellular contexts, which is referred to as oncogenic competence. In melanoma, whether cells in the microenvironment can endow such competence remains unclear. Using a combination of zebrafish transgenesis coupled with human tissues, we demonstrate that GABAergic signaling between keratinocytes and melanocytes promotes melanoma initiation by BRAFV600E. GABA is synthesized in melanoma cells, which then acts on GABA-A receptors in keratinocytes. Electron microscopy demonstrates specialized cell-cell junctions between keratinocytes and melanoma cells, and multielectrode array analysis shows that GABA acts to inhibit electrical activity in melanoma/keratinocyte cocultures. Genetic and pharmacologic perturbation of GABA synthesis abrogates melanoma initiation in vivo. These data suggest that GABAergic signaling across the skin microenvironment regulates the ability of oncogenes to initiate melanoma. SIGNIFICANCE This study shows evidence of GABA-mediated regulation of electrical activity between melanoma cells and keratinocytes, providing a new mechanism by which the microenvironment promotes tumor initiation. This provides insights into the role of the skin microenvironment in early melanomas while identifying GABA as a potential therapeutic target in melanoma. See related commentary by Ceol, p. 2128. This article is featured in Selected Articles from This Issue, p. 2109.
Collapse
Affiliation(s)
- Mohita Tagore
- Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Emiliano Hergenreder
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, New York
- Developmental Biology Program, Sloan Kettering Institute for Cancer Research, New York, New York
- Weill Graduate School of Medical Sciences of Cornell University, New York, New York
| | - Sarah C. Perlee
- Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
- Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Nelly M. Cruz
- Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Laura Menocal
- Weill Graduate School of Medical Sciences of Cornell University, New York, New York
| | - Shruthy Suresh
- Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Eric Chan
- Molecular Cytology Core Facility, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Maayan Baron
- Division of Genetics, Department of Medicine, University of California San Diego, La Jolla, California
| | - Stephanie Melendez
- Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Asim Dave
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Walid K. Chatila
- Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jeremie Nsengimana
- Biostatistics Research Group, Population Health Sciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Richard P. Koche
- Center for Epigenetics Research, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Travis J. Hollmann
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Trey Ideker
- Division of Genetics, Department of Medicine, University of California San Diego, La Jolla, California
| | - Lorenz Studer
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, New York
- Developmental Biology Program, Sloan Kettering Institute for Cancer Research, New York, New York
| | - Andrea Schietinger
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Richard M. White
- Department of Cancer Biology and Genetics, Memorial Sloan Kettering Cancer Center, New York, New York
- Weill Cornell Medical College, New York, New York
- Nuffield Department of Medicine, Ludwig Institute for Cancer Research, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
15
|
Patt L, Tascio D, Domingos C, Timmermann A, Jabs R, Henneberger C, Steinhäuser C, Seifert G. Impact of Developmental Changes of GABA A Receptors on Interneuron-NG2 Glia Transmission in the Hippocampus. Int J Mol Sci 2023; 24:13490. [PMID: 37686294 PMCID: PMC10488269 DOI: 10.3390/ijms241713490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
NG2 glia receive synaptic input from neurons, but the functional impact of this glial innervation is not well understood. In the developing cerebellum and somatosensory cortex the GABAergic input might regulate NG2 glia differentiation and myelination, and a switch from synaptic to extrasynaptic neuron-glia signaling was reported in the latter region. Myelination in the hippocampus is sparse, and most NG2 glia retain their phenotype throughout adulthood, raising the question of the properties and function of neuron-NG2 glia synapses in that brain region. Here, we compared spontaneous and evoked GABAA receptor-mediated currents of NG2 glia in juvenile and adult hippocampi of mice of either sex and assessed the mode of interneuron-glial signaling changes during development. With patch-clamp and pharmacological analyses, we found a decrease in innervation of hippocampal NG2 glia between postnatal days 10 and 60. At the adult stage, enhanced activation of extrasynaptic receptors occurred, indicating a spillover of GABA. This switch from synaptic to extrasynaptic receptor activation was accompanied by downregulation of γ2 and upregulation of the α5 subunit. Molecular analyses and high-resolution expansion microscopy revealed mechanisms of glial GABAA receptor trafficking and clustering. We found that gephyrin and radixin are organized in separate clusters along glial processes. Surprisingly, the developmental loss of γ2 and postsynaptic receptors were not accompanied by altered glial expression of scaffolding proteins, auxiliary receptor subunits or postsynaptic interaction proteins. The GABAergic input to NG2 glia might contribute to the release of neurotrophic factors from these cells and influence neuronal synaptic plasticity.
Collapse
Affiliation(s)
- Linda Patt
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Dario Tascio
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Catia Domingos
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Aline Timmermann
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Ronald Jabs
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
- German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany; (L.P.); (D.T.); (C.D.); (A.T.); (R.J.); (C.H.)
| |
Collapse
|
16
|
Rosenberg EC, Chamberland S, Bazelot M, Nebet ER, Wang X, McKenzie S, Jain S, Greenhill S, Wilson M, Marley N, Salah A, Bailey S, Patra PH, Rose R, Chenouard N, Sun SED, Jones D, Buzsáki G, Devinsky O, Woodhall G, Scharfman HE, Whalley BJ, Tsien RW. Cannabidiol modulates excitatory-inhibitory ratio to counter hippocampal hyperactivity. Neuron 2023; 111:1282-1300.e8. [PMID: 36787750 DOI: 10.1016/j.neuron.2023.01.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/27/2022] [Accepted: 01/20/2023] [Indexed: 02/15/2023]
Abstract
Cannabidiol (CBD), a non-euphoric component of cannabis, reduces seizures in multiple forms of pediatric epilepsies, but the mechanism(s) of anti-seizure action remain unclear. In one leading model, CBD acts at glutamatergic axon terminals, blocking the pro-excitatory actions of an endogenous membrane phospholipid, lysophosphatidylinositol (LPI), at the G-protein-coupled receptor GPR55. However, the impact of LPI-GPR55 signaling at inhibitory synapses and in epileptogenesis remains underexplored. We found that LPI transiently increased hippocampal CA3-CA1 excitatory presynaptic release probability and evoked synaptic strength in WT mice, while attenuating inhibitory postsynaptic strength by decreasing GABAARγ2 and gephyrin puncta. LPI effects at excitatory and inhibitory synapses were eliminated by CBD pre-treatment and absent after GPR55 deletion. Acute pentylenetrazole-induced seizures elevated GPR55 and LPI levels, and chronic lithium-pilocarpine-induced epileptogenesis potentiated LPI's pro-excitatory effects. We propose that CBD exerts potential anti-seizure effects by blocking LPI's synaptic effects and dampening hyperexcitability.
Collapse
Affiliation(s)
- Evan C Rosenberg
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Simon Chamberland
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Michael Bazelot
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Hopkins Life Science Building, Whiteknights, Reading, Berks RG6 6AP, UK; GW Research Ltd, Histon, Cambridge, UK
| | - Erica R Nebet
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Xiaohan Wang
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Sam McKenzie
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Swati Jain
- Departments of Child and Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA; Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Bldg. 35, Orangeburg, NY 10962, USA
| | - Stuart Greenhill
- Aston Neuroscience Institute, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Max Wilson
- Aston Neuroscience Institute, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Nicole Marley
- Aston Neuroscience Institute, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Alejandro Salah
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Shanice Bailey
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Hopkins Life Science Building, Whiteknights, Reading, Berks RG6 6AP, UK
| | - Pabitra Hriday Patra
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Hopkins Life Science Building, Whiteknights, Reading, Berks RG6 6AP, UK
| | - Rebecca Rose
- Department of Advanced Research Technologies, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Nicolas Chenouard
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Simón E D Sun
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Drew Jones
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - György Buzsáki
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Orrin Devinsky
- Department of Neurology, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA
| | - Gavin Woodhall
- Aston Neuroscience Institute, School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Helen E Scharfman
- Departments of Child and Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA; Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Bldg. 35, Orangeburg, NY 10962, USA
| | - Benjamin J Whalley
- School of Chemistry, Food and Nutritional Sciences, and Pharmacy, University of Reading, Hopkins Life Science Building, Whiteknights, Reading, Berks RG6 6AP, UK; GW Research Ltd, Histon, Cambridge, UK
| | - Richard W Tsien
- Department of Neuroscience & Physiology and Neuroscience Institute, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA; Department of Neurology, NYU Langone Medical Center, 435 E 30th St, New York, NY 10016, USA.
| |
Collapse
|
17
|
Hao Y, Liu H, Zeng XT, Wang Y, Zeng WX, Qian KY, Li L, Chi MX, Gao S, Hu Z, Tong XJ. UNC-43/CaMKII-triggered anterograde signals recruit GABA ARs to mediate inhibitory synaptic transmission and plasticity at C. elegans NMJs. Nat Commun 2023; 14:1436. [PMID: 36918518 PMCID: PMC10015018 DOI: 10.1038/s41467-023-37137-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 02/28/2023] [Indexed: 03/16/2023] Open
Abstract
Disturbed inhibitory synaptic transmission has functional impacts on neurodevelopmental and psychiatric disorders. An essential mechanism for modulating inhibitory synaptic transmission is alteration of the postsynaptic abundance of GABAARs, which are stabilized by postsynaptic scaffold proteins and recruited by presynaptic signals. However, how GABAergic neurons trigger signals to transsynaptically recruit GABAARs remains elusive. Here, we show that UNC-43/CaMKII functions at GABAergic neurons to recruit GABAARs and modulate inhibitory synaptic transmission at C. elegans neuromuscular junctions. We demonstrate that UNC-43 promotes presynaptic MADD-4B/Punctin secretion and NRX-1α/Neurexin surface delivery. Together, MADD-4B and NRX-1α recruit postsynaptic NLG-1/Neuroligin and stabilize GABAARs. Further, the excitation of GABAergic neurons potentiates the recruitment of NLG-1-stabilized-GABAARs, which depends on UNC-43, MADD-4B, and NRX-1. These data all support that UNC-43 triggers MADD-4B and NRX-1α, which act as anterograde signals to recruit postsynaptic GABAARs. Thus, our findings elucidate a mechanism for pre- and postsynaptic communication and inhibitory synaptic transmission and plasticity.
Collapse
Affiliation(s)
- Yue Hao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Xian-Ting Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Ya Wang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Wan-Xin Zeng
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Kang-Ying Qian
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ming-Xuan Chi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Shangbang Gao
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Xia-Jing Tong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| |
Collapse
|
18
|
Naylor DE. In the fast lane: Receptor trafficking during status epilepticus. Epilepsia Open 2023; 8 Suppl 1:S35-S65. [PMID: 36861477 PMCID: PMC10173858 DOI: 10.1002/epi4.12718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Status epilepticus (SE) remains a significant cause of morbidity and mortality and often is refractory to standard first-line treatments. A rapid loss of synaptic inhibition and development of pharmacoresistance to benzodiazepines (BZDs) occurs early during SE, while NMDA and AMPA receptor antagonists remain effective treatments after BZDs have failed. Multimodal and subunit-selective receptor trafficking within minutes to an hour of SE involves GABA-A, NMDA, and AMPA receptors and contributes to shifts in the number and subunit composition of surface receptors with differential impacts on the physiology, pharmacology, and strength of GABAergic and glutamatergic currents at synaptic and extrasynaptic sites. During the first hour of SE, synaptic GABA-A receptors containing γ2 subunits move to the cell interior while extrasynaptic GABA-A receptors with δ subunits are preserved. Conversely, NMDA receptors containing N2B subunits are increased at synaptic and extrasynaptic sites, and homomeric GluA1 ("GluA2-lacking") calcium permeant AMPA receptor surface expression also is increased. Molecular mechanisms, largely driven by NMDA receptor or calcium permeant AMPA receptor activation early during circuit hyperactivity, regulate subunit-specific interactions with proteins involved with synaptic scaffolding, adaptin-AP2/clathrin-dependent endocytosis, endoplasmic reticulum (ER) retention, and endosomal recycling. Reviewed here is how SE-induced shifts in receptor subunit composition and surface representation increase the excitatory to inhibitory imbalance that sustains seizures and fuels excitotoxicity contributing to chronic sequela such as "spontaneous recurrent seizures" (SRS). A role for early multimodal therapy is suggested both for treatment of SE and for prevention of long-term comorbidities.
Collapse
Affiliation(s)
- David E Naylor
- VA Greater Los Angeles Healthcare System, Department of Neurology, David Geffen School of Medicine at UCLA, and The Lundquist Institute at Harbor-UCLA Medical Center, Los Angeles, California, USA
| |
Collapse
|
19
|
Hernandez CC, Shen Y, Hu N, Shen W, Narayanan V, Ramsey K, He W, Zou L, Macdonald RL. GABRG2 Variants Associated with Febrile Seizures. Biomolecules 2023; 13:414. [PMID: 36979350 PMCID: PMC10046037 DOI: 10.3390/biom13030414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Febrile seizures (FS) are the most common form of epilepsy in children between six months and five years of age. FS is a self-limited type of fever-related seizure. However, complicated prolonged FS can lead to complex partial epilepsy. We found that among the GABAA receptor subunit (GABR) genes, most variants associated with FS are harbored in the γ2 subunit (GABRG2). Here, we characterized the effects of eight variants in the GABAA receptor γ2 subunit on receptor biogenesis and channel function. Two-thirds of the GABRG2 variants followed the expected autosomal dominant inheritance in FS and occurred as missense and nonsense variants. The remaining one-third appeared as de novo in the affected probands and occurred only as missense variants. The loss of GABAA receptor function and dominant negative effect on GABAA receptor biogenesis likely caused the FS phenotype. In general, variants in the GABRG2 result in a broad spectrum of phenotypic severity, ranging from asymptomatic, FS, genetic epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome individuals. The data presented here support the link between FS, epilepsy, and GABRG2 variants, shedding light on the relationship between the variant topological occurrence and disease severity.
Collapse
Affiliation(s)
- Ciria C. Hernandez
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yanwen Shen
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Ningning Hu
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wangzhen Shen
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Vinodh Narayanan
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Keri Ramsey
- Center for Rare Childhood Disorders, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Wen He
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Liping Zou
- Department of Pediatrics, Seventh Medical Center of Chinese PLA General Hospital, Beijing 100010, China
| | - Robert L. Macdonald
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| |
Collapse
|
20
|
Wang Z, Choi K. Pharmacological modulation of chloride channels as a therapeutic strategy for neurological disorders. Front Physiol 2023; 14:1122444. [PMID: 36935741 PMCID: PMC10017882 DOI: 10.3389/fphys.2023.1122444] [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: 12/12/2022] [Accepted: 02/09/2023] [Indexed: 03/06/2023] Open
Abstract
Chloride homeostasis is critical in the physiological functions of the central nervous system (CNS). Its concentration is precisely regulated by multiple ion-transporting proteins such as chloride channels and transporters that are widely distributed in the brain cells, including neurons and glia. Unlike ion transporters, chloride channels provide rapid responses to efficiently regulate ion flux. Some of chloride channels are also permeable to selected organic anions such as glutamate and γ-aminobutyric acid, suggesting neuroexcitatory and neuroinhibitory functions while gating. Dysregulated chloride channels are implicated in neurological disorders, e.g., ischemia and neuroinflammation. Modulation of chloride homeostasis through chloride channels has been suggested as a potential therapeutic approach for neurological disorders. The drug design for CNS diseases is challenging because it requires the therapeutics to traverse the blood-brain-barrier. Small molecules are a well-established modality with better cell permeability due to their lower molecular weight and flexibility for structure optimization compared to biologics. In this article, we describe the important roles of chloride homeostasis in each type of brain cells and introduce selected chloride channels identified in the CNS. We then discuss the contribution of their dysregulations towards the pathogenesis of neurological disorders, emphasizing the potential of targeting chloride channels as a therapeutic strategy for CNS disease treatment. Along with this literature survey, we summarize the small molecules that modulate chloride channels and propose the potential strategy of optimizing existing drugs to brain-penetrants to support future CNS drug discovery.
Collapse
|
21
|
Loss of CDKL5 Causes Synaptic GABAergic Defects That Can Be Restored with the Neuroactive Steroid Pregnenolone-Methyl-Ether. Int J Mol Sci 2022; 24:ijms24010068. [PMID: 36613509 PMCID: PMC9820583 DOI: 10.3390/ijms24010068] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/09/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
CDKL5 deficiency disorder (CDD) is an X-linked neurodevelopmental disorder characterised by early-onset drug-resistant epilepsy and impaired cognitive and motor skills. CDD is caused by mutations in cyclin-dependent kinase-like 5 (CDKL5), which plays a well-known role in regulating excitatory neurotransmission, while its effect on neuronal inhibition has been poorly investigated. We explored the potential role of CDKL5 in the inhibitory compartment in Cdkl5-KO male mice and primary hippocampal neurons and found that CDKL5 interacts with gephyrin and collybistin, two crucial organisers of the inhibitory postsynaptic sites. Through molecular and electrophysiological approaches, we demonstrated that CDKL5 loss causes a reduced number of gephyrin puncta and surface exposed γ2 subunit-containing GABAA receptors, impacting the frequency of miniature inhibitory postsynaptic currents, which we ascribe to a postsynaptic function of CDKL5. In line with previous data showing that CDKL5 loss impacts microtubule (MT) dynamics, we showed that treatment with pregnenolone-methyl-ether (PME), which promotes MT dynamics, rescues the above defects. The impact of CDKL5 deficiency on inhibitory neurotransmission might explain the presence of drug-resistant epilepsy and cognitive defects in CDD patients. Moreover, our results may pave the way for drug-based therapies that could bypass the need for CDKL5 and provide effective therapeutic strategies for CDD patients.
Collapse
|
22
|
Zhang M, Kou L, Qin Y, Chen J, Bai D, Zhao L, Lin H, Jiang G. A bibliometric analysis of the recent advances in diazepam from 2012 to 2021. Front Pharmacol 2022; 13:1042594. [DOI: 10.3389/fphar.2022.1042594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
Background: Diazepam is a classic benzodiazepine drug that has been widely used for disorders such as anxiety, sleep disorders, and epilepsy, over the past 59 years. The study of diazepam has always been an important research topic. However, there are few bibliometric analyses or systematic studies in this field. This study undertook bibliometric and visual analysis to ascertain the current status of diazepam research, and to identify research hotspots and trends in the past 10 years, to better understand future developments in basic and clinical research.Methods: Articles and reviews of diazepam were retrieved from the Web of Science core collection. Using CiteSpace, VOSviewer, and Scimago Graphica software, countries, institutions, authors, journals, references, and keywords in the field were visually analyzed.Results: A total of 3,870 publications were included. Diazepam-related literature had high volumes of publications and citations. The majority of publications were from the USA and China. The highest number of publications and co-citations, among the authors, was by James M Cook. Epilepsia and the Latin American Journal of Pharmacy were the journals with the most publications on diazepam and Epilepsia was the most frequently cited journal. Through a comprehensive analysis of keywords and references, we found that current research on diazepam has focused on its mechanism of action, application in disease, pharmacokinetics, risk, assessment, and management of use, status epilepticus, gamma-aminobutyric acid receptors (GABAR), intranasal formulation, gephyrin, and that ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is the current research hotspot.Conclusion: Research on diazepam is flourishing. We identified research hotspots and trends in diazepam research using bibliometric and visual analytic methods. The clinical applications, mechanisms of action, pharmacokinetics, and assessment and management of the use of diazepam are the focus of current research and the development trend of future research.
Collapse
|
23
|
Barker CM, Miles KD, Doll CA. Fmrp regulates neuronal balance in embryonic motor circuit formation. Front Neurosci 2022; 16:962901. [PMID: 36408418 PMCID: PMC9669763 DOI: 10.3389/fnins.2022.962901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022] Open
Abstract
Motor behavior requires the balanced production and integration of a variety of neural cell types. Motor neurons are positioned in discrete locations in the spinal cord, targeting specific muscles to drive locomotive contractions. Specialized spinal interneurons modulate and synchronize motor neuron activity to achieve coordinated motor output. Changes in the ratios and connectivity of spinal interneurons could drastically alter motor output by tipping the balance of inhibition and excitation onto target motor neurons. Importantly, individuals with Fragile X syndrome (FXS) and associated autism spectrum disorders often have significant motor challenges, including repetitive behaviors and epilepsy. FXS stems from the transcriptional silencing of the gene Fragile X Messenger Ribonucleoprotein 1 (FMR1), which encodes an RNA binding protein that is implicated in a multitude of crucial neurodevelopmental processes, including cell specification. Our work shows that Fmrp regulates the formation of specific interneurons and motor neurons that comprise early embryonic motor circuits. We find that zebrafish fmr1 mutants generate surplus ventral lateral descending (VeLD) interneurons, an early-born cell derived from the motor neuron progenitor domain (pMN). As VeLD interneurons are hypothesized to act as central pattern generators driving the earliest spontaneous movements, this imbalance could influence the formation and long-term function of motor circuits driving locomotion. fmr1 embryos also show reduced expression of proteins associated with inhibitory synapses, including the presynaptic transporter vGAT and the postsynaptic scaffold Gephyrin. Taken together, we show changes in embryonic motor circuit formation in fmr1 mutants that could underlie persistent hyperexcitability.
Collapse
Affiliation(s)
- Chase M. Barker
- Section of Developmental Biology, Department of Pediatrics, Children’s Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, United States
| | - Kaleb D. Miles
- Section of Developmental Biology, Department of Pediatrics, Children’s Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, United States
- Biomedical Sciences and Biotechnology Program, Graduate School, University of Colorado, Aurora, CO, United States
| | - Caleb A. Doll
- Section of Developmental Biology, Department of Pediatrics, Children’s Hospital Colorado, University of Colorado School of Medicine, Aurora, CO, United States
| |
Collapse
|
24
|
Nwosu G, Reddy SB, Riordan HRM, Kang JQ. Variable Expression of GABAA Receptor Subunit Gamma 2 Mutation in a Nuclear Family Displaying Developmental and Encephalopathic Phenotype. Int J Mol Sci 2022; 23:9683. [PMID: 36077081 PMCID: PMC9456057 DOI: 10.3390/ijms23179683] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/13/2022] [Accepted: 08/23/2022] [Indexed: 12/17/2022] Open
Abstract
Mutations in GABAA receptor subunit genes (GABRs) are a major etiology for developmental and epileptic encephalopathies (DEEs). This article reports a case of a genetic abnormality in GABRG2 and updates the pathophysiology and treatment development for mutations in DEEs based on recent advances. Mutations in GABRs, especially in GABRA1, GABRB2, GABRB3, and GABRG2, impair GABAergic signaling and are frequently associated with DEEs such as Dravet syndrome and Lennox-Gastaut syndrome, as GABAergic signaling is critical for early brain development. We here present a novel association of a microdeletion of GABRG2 with a diagnosed DEE phenotype. We characterized the clinical phenotype and underlying mechanisms, including molecular genetics, EEGs, and MRI. We then compiled an update of molecular mechanisms of GABR mutations, especially the mutations in GABRB3 and GABRG2 attributed to DEEs. Genetic therapy is also discussed as a new avenue for treatment of DEEs through employing antisense oligonucleotide techniques. There is an urgent need to define treatment targets and explore new treatment paradigms for the DEEs, as early deployment could alleviate long-term disabilities and improve quality of life for patients. This study highlights biomolecular targets for future therapeutic interventions, including via both pharmacological and genetic approaches.
Collapse
Affiliation(s)
- Gerald Nwosu
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN 37208, USA
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Brain Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Shilpa B. Reddy
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Heather Rose Mead Riordan
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Jing-Qiong Kang
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Brain Institute, Vanderbilt University, Nashville, TN 37232, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37233, USA
| |
Collapse
|
25
|
Guzikowski NJ, Kavalali ET. Nano-organization of spontaneous GABAergic transmission directs its autonomous function in neuronal signaling. Cell Rep 2022; 40:111172. [PMID: 35947950 PMCID: PMC9392417 DOI: 10.1016/j.celrep.2022.111172] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 04/12/2022] [Accepted: 07/15/2022] [Indexed: 01/04/2023] Open
Abstract
Earlier studies delineated the precise arrangement of proteins that drive neurotransmitter release and postsynaptic signaling at excitatory synapses. However, spatial organization of neurotransmission at inhibitory synapses remains unclear. Here, we took advantage of the molecularly specific interaction of antimalarial artemisinins and the inhibitory synapse scaffold protein, gephyrin, to probe the functional organization of gamma-aminobutyric acid A receptor (GABAAR)-mediated neurotransmission in central synapses. Short-term application of artemisinins severely contracts the size and density of gephyrin and GABAaR γ2 subunit clusters. This size contraction elicits a neuronal activity-independent increase in Bdnf expression due to a specific reduction in GABAergic spontaneous, but not evoked, neurotransmission. The same functional effect could be mimicked by disruption of microtubules that link gephyrin to the neuronal cytoskeleton. These results suggest that the GABAergic postsynaptic apparatus possesses a concentric center-surround organization, where the periphery of gephyrin clusters selectively maintains spontaneous GABAergic neurotransmission facilitating its autonomous function regulating Bdnf expression.
Collapse
Affiliation(s)
- Natalie J. Guzikowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Ege T. Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA,Lead contact,Correspondence:
| |
Collapse
|
26
|
Mast N, Li Y, Pikuleva IA. Increased Acetylcholine Levels and Other Brain Effects in 5XFAD Mice after Treatment with 8,14-Dihydroxy Metabolite of Efavirenz. Int J Mol Sci 2022; 23:ijms23147669. [PMID: 35887013 PMCID: PMC9317559 DOI: 10.3390/ijms23147669] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/06/2022] [Accepted: 07/09/2022] [Indexed: 02/08/2023] Open
Abstract
Efavirenz (EFV), an FDA-approved anti-HIV drug, has off-target binding to CYP46A1, the CNS enzyme which converts cholesterol to 24-hydroxycholesterol. At small doses, EFV allosterically activates CYP46A1 in mice and humans and mitigates some of the Alzheimer's disease manifestations in 5XFAD mice, an animal model. Notably, in vitro, all phase 1 EFV hydroxymetabolites activate CYP46A1 as well and bind either to the allosteric site for EFV, neurotransmitters or both. Herein, we treated 5XFAD mice with 8,14-dihydroxyEFV, the binder to the neurotransmitter allosteric site, which elicits the highest CYP46A1 activation in vitro. We found that treated animals of both sexes had activation of CYP46A1 and cholesterol turnover in the brain, decreased content of the amyloid beta 42 peptide, increased levels of acetyl-CoA and acetylcholine, and altered expression of the brain marker proteins. In addition, male mice had improved performance in the Barnes Maze test and increased expression of the acetylcholine-related genes. This work expands our knowledge of the beneficial CYP46A1 activation effects and demonstrates that 8,14-dihydroxyEFV crosses the blood-brain barrier and has therapeutic potential as a CYP46A1 activator.
Collapse
|
27
|
Uygun DS, Basheer R. Circuits and components of delta wave regulation. Brain Res Bull 2022; 188:223-232. [PMID: 35738502 DOI: 10.1016/j.brainresbull.2022.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 06/07/2022] [Accepted: 06/14/2022] [Indexed: 11/02/2022]
Abstract
Sleep is vital and the deepest stages of sleep occur within Non-rapid-eye-movement sleep (NREM), defined by high electroencephalographic power in the delta (~0.5-4Hz) wave frequency range. Delta waves are thought to facilitate a myriad of physical and mental health functions. This review aims to comprehensively cover the historical and recent advances in the understanding of the mechanisms orchestrating NREM delta waves. We discuss a complete neurocircuit - focusing on one leg of the circuit at a time - and delve deeply into the molecular mechanistic components that contribute to NREM delta wave regulation. We also discuss the relatively localized nature in which these mechanisms have been defined, and how likely they might generalize across distinct sensory and higher order modalities in the brain.
Collapse
Affiliation(s)
- David S Uygun
- VA Boston Healthcare System and Harvard Medical School, Dept. of Psychiatry, West Roxbury, MA; 02132.
| | - Radhika Basheer
- VA Boston Healthcare System and Harvard Medical School, Dept. of Psychiatry, West Roxbury, MA; 02132.
| |
Collapse
|
28
|
Complex regulation of Gephyrin splicing is a determinant of inhibitory postsynaptic diversity. Nat Commun 2022; 13:3507. [PMID: 35717442 PMCID: PMC9206673 DOI: 10.1038/s41467-022-31264-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/10/2022] [Indexed: 01/05/2023] Open
Abstract
Gephyrin (GPHN) regulates the clustering of postsynaptic components at inhibitory synapses and is involved in pathophysiology of neuropsychiatric disorders. Here, we uncover an extensive diversity of GPHN transcripts that are tightly controlled by splicing during mouse and human brain development. Proteomic analysis reveals at least a hundred isoforms of GPHN incorporated at inhibitory Glycine and gamma-aminobutyric acid A receptors containing synapses. They exhibit different localization and postsynaptic clustering properties, and altering the expression level of one isoform is sufficient to affect the number, size, and density of inhibitory synapses in cerebellar Purkinje cells. Furthermore, we discovered that splicing defects reported in neuropsychiatric disorders are carried by multiple alternative GPHN transcripts, demonstrating the need for a thorough analysis of the GPHN transcriptome in patients. Overall, we show that alternative splicing of GPHN is an important genetic variation to consider in neurological diseases and a determinant of the diversity of postsynaptic inhibitory synapses. The protein gephyrin is involved in organizing synapses. Here, the authors show how different transcripts of gephyrin form and regulate inhibitory synapses.
Collapse
|
29
|
Tipton AE, Russek SJ. Regulation of Inhibitory Signaling at the Receptor and Cellular Level; Advances in Our Understanding of GABAergic Neurotransmission and the Mechanisms by Which It Is Disrupted in Epilepsy. Front Synaptic Neurosci 2022; 14:914374. [PMID: 35874848 PMCID: PMC9302637 DOI: 10.3389/fnsyn.2022.914374] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/17/2022] [Indexed: 11/13/2022] Open
Abstract
Inhibitory signaling in the brain organizes the neural circuits that orchestrate how living creatures interact with the world around them and how they build representations of objects and ideas. Without tight control at multiple points of cellular engagement, the brain’s inhibitory systems would run down and the ability to extract meaningful information from excitatory events would be lost leaving behind a system vulnerable to seizures and to cognitive decline. In this review, we will cover many of the salient features that have emerged regarding the dynamic regulation of inhibitory signaling seen through the lens of cell biology with an emphasis on the major building blocks, the ligand-gated ion channel receptors that are the first transduction point when the neurotransmitter GABA is released into the synapse. Epilepsy association will be used to indicate importance of key proteins and their pathways to brain function and to introduce novel areas for therapeutic intervention.
Collapse
Affiliation(s)
- Allison E. Tipton
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
- Biomolecular Pharmacology Program, Boston University School of Medicine, Boston, MA, United States
- Boston University MD/PhD Training Program, Boston, MA, United States
| | - Shelley J. Russek
- Biomolecular Pharmacology Program, Boston University School of Medicine, Boston, MA, United States
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
- Boston University MD/PhD Training Program, Boston, MA, United States
- *Correspondence: Shelley J. Russek,
| |
Collapse
|
30
|
Abstract
Neurexin-3 is primarily localized in the presynaptic membrane and forms complexes with various ligands located in the postsynaptic membrane. Neurexin-3 has important roles in synapse development and synapse functions. Neurexin-3 mediates excitatory presynaptic differentiation by interacting with leucine-rich-repeat transmembrane neuronal proteins. Meanwhile, neurexin-3 modulates the expression of presynaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors and γ-aminobutyric acid A receptors by interacting with neuroligins at excitatory and inhibitory synapses. Numerous studies have documented the potential contribution of neurexin-3 to neurodegenerative and neuropsychiatric disorders, such as Alzheimer's disease, addiction behaviors, and other diseases, which raises hopes that understanding the mechanisms of neurexin-3 may hold the key to developing new strategies for related illnesses. This review comprehensively covers the literature to provide current knowledge of the structure, function, and clinical role of neurexin-3.
Collapse
|
31
|
Cao T, Chen H, Huang W, Xu S, Liu P, Zou W, Pang M, Xu Y, Bai X, Liu B, Rong L, Cui ZK, Li M. hUC-MSC-mediated recovery of subacute spinal cord injury through enhancing the pivotal subunits β3 and γ2 of the GABA A receptor. Theranostics 2022; 12:3057-3078. [PMID: 35547766 PMCID: PMC9065192 DOI: 10.7150/thno.72015] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 03/12/2022] [Indexed: 12/19/2022] Open
Abstract
Rationale: Spinal cord injury (SCI) remains an incurable neurological disorder leading to permanent and profound neurologic deficits and disabilities. Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are particularly appealing in SCI treatment to curtail damage, restore homeostasis and possible neural relay. However, the detailed mechanisms underlying hUC-MSC-mediated functional recovery of SCI have not been fully elucidated. The purpose of our current study is to identify novel therapeutic targets and depict the molecular mechanisms underlying the hUC-MSC-mediated recovery of subacute SCI. Methods: Adult female rats suffering from subacute incomplete thoracic SCI were treated with intrathecal transplantation of hUC-MSCs. The beneficial effects of hUC-MSCs on SCI repair were evaluated by a series of behavioral analyses, motor evoked potentials (MEPs) recording of hindlimb and immunohistochemistry. We carried out extensive transcriptome comparative analyses of spinal cord tissues at the lesion site from the subacute phase of SCI (sub-SCI) either treated without (+PBS) or with hUC-MSCs (+MSC) at 0 (sub-SCI), 1, 2, and 4 weeks post-transplantation (wpt), as well as normal spinal cord segments of intact/sham rats (Intact). Adeno-associated virus (AAV)-mediated neuron-specific expression system was employed to functionally screen specific γ-aminobutyric acid type A receptor (GABAAR) subunits promoting the functional recovery of SCI in vivo. The mature cortical axon scrape assay and transplantation of genetically modified MSCs with either overexpression or knockdown of brain-derived neurotrophic factor (BDNF) were employed to demonstrate that hUC-MSCs ameliorated the reduction of GABAAR subunits in the injured spinal cord via BDNF secretion in vitro and in vivo, respectively. Results: Comparative transcriptome analysis revealed the GABAergic synapse pathway is significantly enriched as a main target of hUC-MSC-activated genes in the injured spinal cord. Functional screening of the primary GABAAR subunits uncovered that Gabrb3 and Garbg2 harbored the motor and electrophysiological recovery-promoting competence. Moreover, targeting either of the two pivotal subunits β3 or γ2 in combination with/without the K+/Cl- cotransporter 2 (KCC2) reinforced the therapeutic effects. Mechanistically, BDNF secreted by hUC-MSCs contributed to the upregulation of GABAAR subunits (β3 & γ2) and KCC2 in the injured neurons. Conclusions: Our study identifies a novel mode for hUC-MSC-mediated locomotor recovery of SCI through synergistic upregulation of GABAAR β3 and γ2 along with KCC2 by BDNF secretion, indicating the significance of restoring the excitation/inhibition balance in the injured neurons for the reestablishment of neuronal circuits. This study also provides a potential combinatorial approach by targeting the pivotal subunit β3 or γ2 and KCC2, opening up possibilities for efficacious drug design.
Collapse
Affiliation(s)
- Tingting Cao
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Huan Chen
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Weiping Huang
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Sisi Xu
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Peilin Liu
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Weiwei Zou
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Mao Pang
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510515, China
- Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, 510630, China
- Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, 510630, China
| | - Ying Xu
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510515, China
- Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, 510630, China
- Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, 510630, China
| | - Xiaochun Bai
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Bin Liu
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510515, China
- Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, 510630, China
- Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, 510630, China
| | - Limin Rong
- Department of Spine Surgery, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510515, China
- Guangdong Provincial Center for Engineering and Technology Research of Minimally Invasive Spine Surgery, 510630, China
- Guangdong Provincial Center for Quality Control of Minimally Invasive Spine Surgery, 510630, China
| | - Zhong-Kai Cui
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Mangmang Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| |
Collapse
|
32
|
Mikroulis A, Ledri M, Ruffolo G, Palma E, Sperk G, Dalli J, Vezzani A, Kokaia M. Lipid mediator n-3 docosapentaenoic acid-derived protectin D1 enhances synaptic inhibition of hippocampal principal neurons by interaction with a G-protein-coupled receptor. FASEB J 2022; 36:e22203. [PMID: 35188290 PMCID: PMC9306510 DOI: 10.1096/fj.202101815r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 01/16/2023]
Abstract
Epilepsy is a severe neurological disease manifested by spontaneous recurrent seizures due to abnormal hyper‐synchronization of neuronal activity. Epilepsy affects about 1% of the population and up to 40% of patients experience seizures that are resistant to currently available drugs, thus highlighting an urgent need for novel treatments. In this regard, anti‐inflammatory drugs emerged as potential therapeutic candidates. In particular, specific molecules apt to resolve the neuroinflammatory response occurring in acquired epilepsies have been proven to counteract seizures in experimental models, and humans. One candidate investigational molecule has been recently identified as the lipid mediator n‐3 docosapentaenoic acid‐derived protectin D1 (PD1n‐3DPA) which significantly reduced seizures, cell loss, and cognitive deficit in a mouse model of acquired epilepsy. However, the mechanisms that mediate the PD1n‐3DPA effect remain elusive. We here addressed whether PD1n‐3DPA has direct effects on neuronal activity independent of its anti‐inflammatory action. We incubated, therefore, hippocampal slices with PD1n‐3DPA and investigated its effect on excitatory and inhibitory synaptic inputs to the CA1 pyramidal neurons. We demonstrate that inhibitory drive onto the perisomatic region of the pyramidal neurons is increased by PD1n‐3DPA, and this effect is mediated by pertussis toxin‐sensitive G‐protein coupled receptors. Our data indicate that PD1n‐3DPA acts directly on inhibitory transmission, most likely at the presynaptic site of inhibitory synapses as also supported by Xenopus oocytes and immunohistochemical experiments. Thus, in addition to its anti‐inflammatory effects, PD1n‐3DPA anti‐seizure and neuroprotective effects may be mediated by its direct action on neuronal excitability by modulating their synaptic inputs.
Collapse
Affiliation(s)
- Apostolos Mikroulis
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Marco Ledri
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy.,IRCCS San Raffaele Pisana, Rome, Italy
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Günther Sperk
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Jesmond Dalli
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.,Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, London, UK
| | - Annamaria Vezzani
- Mario Negri Institute for Pharmacological Research IRCCS, Milan, Italy
| | - Merab Kokaia
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| |
Collapse
|
33
|
Luquin E, Paternain B, Zugasti I, Santomá C, Mengual E. Stereological estimations and neurochemical characterization of neurons expressing GABAA and GABAB receptors in the rat pedunculopontine and laterodorsal tegmental nuclei. Brain Struct Funct 2022; 227:89-110. [PMID: 34510281 PMCID: PMC8741722 DOI: 10.1007/s00429-021-02375-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 08/31/2021] [Indexed: 11/29/2022]
Abstract
To better understand GABAergic transmission at two targets of basal ganglia downstream projections, the pedunculopontine (PPN) and laterodorsal (LDT) tegmental nuclei, the anatomical localization of GABAA and GABAB receptors was investigated in both nuclei. Specifically, the total number of neurons expressing the GABAA receptor γ2 subunit (GABAAR γ2) and the GABAB receptor R2 subunit (GABAB R2) in PPN and LDT was estimated using stereological methods, and the neurochemical phenotype of cells expressing each subunit was also determined. The mean number of non-cholinergic cells expressing GABAAR γ2 was 9850 ± 1856 in the PPN and 8285 ± 962 in the LDT, whereas those expressing GABAB R2 were 7310 ± 1970 and 9170 ± 1900 in the PPN and LDT, respectively. In addition, all cholinergic neurons in both nuclei co-expressed GABAAR γ2 and 95-98% of them co-expressed GABAB R2. Triple labeling using in situ hybridization revealed that 77% of GAD67 mRNA-positive cells in the PPT and 49% in the LDT expressed GABAAR γ2, while 90% (PPN) and 65% (LDT) of Vglut2 mRNA-positive cells also expressed GABAAR γ2. In contrast, a similar proportion (~2/3) of glutamatergic and GABAergic cells co-expressed GABAB R2 in both nuclei. The heterogeneous distribution of GABAAR and GABABR among non-cholinergic cells in PPN and LDT may give rise to physiological differences within each neurochemical subpopulation. In addition, the dissimilar proportion of GABAAR γ2-expressing glutamatergic and GABAergic neurons in the PPN and LDT may contribute to some of the functional differences found between the two nuclei.
Collapse
Affiliation(s)
- Esther Luquin
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Beatriz Paternain
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Inés Zugasti
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Carmen Santomá
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Elisa Mengual
- Department of Pathology, Anatomy, and Physiology, School of Medicine, University of Navarra, Ed. Los Castaños, Irunlarrea 1, 31008 Pamplona, Spain
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| |
Collapse
|
34
|
Yorgason JT, Wadsworth HA, Anderson EJ, Williams BM, Brundage JN, Hedges DM, Stockard AL, Jones ST, Arthur SB, Hansen DM, Schilaty ND, Jang EY, Lee AM, Wallner M, Steffensen SC. Modulation of dopamine release by ethanol is mediated by atypical GABA A receptors on cholinergic interneurons in the nucleus accumbens. Addict Biol 2022; 27:e13108. [PMID: 34713509 DOI: 10.1111/adb.13108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/31/2021] [Accepted: 09/24/2021] [Indexed: 12/18/2022]
Abstract
Previous studies indicate that moderate-to-high ethanol (EtOH) concentrations enhance dopamine (DA) neurotransmission in the mesolimbic DA system from the ventral tegmental area (VTA) and projecting to the nucleus accumbens core (NAc). However, voltammetry studies demonstrate that moderate-to-high EtOH concentrations decrease evoked DA release at NAc terminals. The involvement of γ-aminobutyric acid (GABA) receptors (GABAA Rs), glycine (GLY) receptors (GLYRs) and cholinergic interneurons (CINs) in mediating EtOH inhibition of evoked NAc DA release were examined. Fast scan cyclic voltammetry, electrophysiology, optogenetics and immunohistochemistry techniques were used to evaluate the effects of acute and chronic EtOH exposure on DA release and CIN activity in C57/BL6, CD-1, transgenic mice and δ-subunit knockout (KO) mice (δ-/-). Ethanol decreased DA release in mice with an IC50 of 80 mM ex vivo and 2.0 g/kg in vivo. GABA and GLY decreased evoked DA release at 1-10 mM. Typical GABAA R agonists inhibited DA release at high concentrations. Typical GABAA R antagonists had minimal effects on EtOH inhibition of evoked DA release. However, EtOH inhibition of DA release was blocked by the α4 β3 δ GABAA R antagonist Ro15-4513, the GLYR antagonist strychnine and by the GABA ρ1 (Rho-1) antagonist TPMPA (10 μM) and reduced significantly in GABAA R δ-/- mice. Rho-1 expression was observed in CINs. Ethanol inhibited GABAergic synaptic input to CINs from the VTA and enhanced firing rate, both of which were blocked by TPMPA. Results herein suggest that EtOH inhibition of DA release in the NAc is modulated by GLYRs and atypical GABAA Rs on CINs containing δ- and Rho-subunits.
Collapse
Affiliation(s)
- Jordan T Yorgason
- Department of Cellular Biology and Physiology, Brigham Young University, Provo, Utah, USA
| | - Hillary A Wadsworth
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Elizabeth J Anderson
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Benjamin M Williams
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - James N Brundage
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - David M Hedges
- Enterprise Information Management, Billings Clinic, Billings, Montana, USA
| | - Alyssa L Stockard
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Stephen T Jones
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Summer B Arthur
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - David Micah Hansen
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| | - Nathan D Schilaty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Eun Young Jang
- Research Center for Convergence Toxicology, Korea Institute of Toxicology, Daejeon, South Korea
| | - Anna M Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Martin Wallner
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, USA
| | - Scott C Steffensen
- Department of Psychology and Center for Neuroscience, Brigham Young University, Provo, Utah, USA
| |
Collapse
|
35
|
The interactions of alcohol and cocaine regulate the expression of genes involved in the GABAergic, glutamatergic and endocannabinoid systems of male and female rats. Neuropharmacology 2021; 206:108937. [PMID: 34965406 DOI: 10.1016/j.neuropharm.2021.108937] [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] [Received: 04/08/2021] [Revised: 12/16/2021] [Accepted: 12/21/2021] [Indexed: 11/23/2022]
Abstract
Although the pharmacological and behavioural interactions between cocaine and alcohol are well established, less is known about how polyconsumption of these drugs affects the neurotransmitter systems involved in their psychoactive effects and in particular, in the process of addiction. Here, rats of both sexes at two stages of development were studied under a chronic regime of intravenous cocaine and/or alcohol administration. Brain samples from the medial prefrontal cortex, nucleus accumbens, hippocampus and amygdala were extracted to analyse the mRNA expression of genes encoding subunits of the GABA, NMDA and AMPA receptors, as well as the expression of the CB1 receptor, and that of enzymes related to the biosynthesis and degradation of endocannabinoids. Moreover, two synaptic scaffold proteins related to GABA and NMDA receptors, gephyrin and PSD-95, were quantified in Western blots. Significant interactions between cocaine and alcohol were common, affecting the GABAergic and endocannabinoid systems in the medial prefrontal cortex and amygdala of young adults, whereas such interactions were evident in the glutamatergic and endocannabinoid systems in adults, as well as a more pronounced sex effect. Significant interactions between these drugs affecting the scaffold proteins were evident in the medial prefrontal cortex and nucleus accumbens of young adults, and in the nucleus accumbens and amygdala of adults, but not in the hippocampus. These results highlight the importance of considering the interactions between cocaine and alcohol on neurotransmitter systems in the context of polyconsumption, specifically when treating problems of abuse of these two substances.
Collapse
|
36
|
Garcia JD, Gookin SE, Crosby KC, Schwartz SL, Tiemeier E, Kennedy MJ, Dell'Acqua ML, Herson PS, Quillinan N, Smith KR. Stepwise disassembly of GABAergic synapses during pathogenic excitotoxicity. Cell Rep 2021; 37:110142. [PMID: 34936876 PMCID: PMC8824488 DOI: 10.1016/j.celrep.2021.110142] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 09/17/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022] Open
Abstract
GABAergic synaptic inhibition controls neuronal firing, excitability, and synaptic plasticity to regulate neuronal circuits. Following an acute excitotoxic insult, inhibitory synapses are eliminated, reducing synaptic inhibition, elevating circuit excitability, and contributing to the pathophysiology of brain injuries. However, mechanisms that drive inhibitory synapse disassembly and elimination are undefined. We find that inhibitory synapses are disassembled in a sequential manner following excitotoxicity: GABAARs undergo rapid nanoscale rearrangement and are dispersed from the synapse along with presynaptic active zone components, followed by the gradual removal of the gephyrin scaffold, prior to complete elimination of the presynaptic terminal. GABAAR nanoscale reorganization and synaptic declustering depends on calcineurin signaling, whereas disassembly of gephyrin relies on calpain activation, and blockade of both enzymes preserves inhibitory synapses after excitotoxic insult. Thus, inhibitory synapse disassembly occurs rapidly, with nanoscale precision, in a stepwise manner and most likely represents a critical step in the progression of hyperexcitability following excitotoxicity.
Collapse
Affiliation(s)
- Joshua D Garcia
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Sara E Gookin
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Kevin C Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Samantha L Schwartz
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Erika Tiemeier
- Department of Anesthesiology, Neuronal Injury Program, University of Colorado School of Medicine, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA
| | - Paco S Herson
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA; Department of Anesthesiology, Neuronal Injury Program, University of Colorado School of Medicine, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Nidia Quillinan
- Department of Anesthesiology, Neuronal Injury Program, University of Colorado School of Medicine, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, 12800 East 19th Avenue, Aurora, CO 80045, USA.
| |
Collapse
|
37
|
Gatica RI, Aguilar-Rivera M, Henny P, Fuentealba JA. Susceptibility to express amphetamine locomotor sensitization correlates with dorsolateral striatum bursting activity and GABAergic synapses in the globus pallidus. Brain Res Bull 2021; 179:83-96. [PMID: 34920034 DOI: 10.1016/j.brainresbull.2021.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/09/2021] [Accepted: 12/12/2021] [Indexed: 11/18/2022]
Abstract
Repeated psychostimulant administration results in behavioral sensitization, a process that is relevant in the early phases of drug addiction. Critically, behavioral sensitization is not observed in all subjects. Evidence shows that differential neuronal activity in the dorsolateral striatum (DLS) accompanies the expression of amphetamine (AMPH) locomotor sensitization. However, whether individual differences in DLS activity previous to AMPH administration can predict the expression of locomotor sensitization has not been assessed. Here, we examined DLS neuronal activity before and after repeated AMPH administration and related it to the susceptibility of rats to sensitize. For that, single-unit recordings on DLS medium spiny neurons (MSNs) were carried out in freely moving male Sprague Dawley rats during repeated AMPH administration. We also examined differences in neurostructure that could accompany sensitization. We quantified the density of the inhibitory postsynaptic marker gephyrin (Geph) in the entopeduncular nucleus (EP) and globus pallidus (GP). A higher burst firing and a lower percentage of correlation between MSNs post-Saline firing rate vs. locomotion predicted the expression of locomotor sensitization. Moreover, during the AMPH challenge, we observed that burst firing decreased in sensitized rats, in contrast to non-sensitized rats in which burst firing was maintained. Finally, a higher Geph density on GP but not EP was observed in non-sensitized rats after AMPH challenge. These results indicate that initial differences in DLS burst firing might underlie the susceptibility to express locomotor sensitization and suggest that the potentiation of dorsal striatum indirect pathway could be considered a protective mechanism to locomotor sensitization.
Collapse
Affiliation(s)
- Rafael Ignacio Gatica
- Laboratorio de Neuroquímica, Departamento de Farmacia, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820244, Chile; Laboratorio de Neuroanatomía, Departamento de Anatomía, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330023, Chile; Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 8330023, Chile
| | - Marcelo Aguilar-Rivera
- Department of Bioengineering, University of California, La Jolla, San Diego, CA 92093, USA
| | - Pablo Henny
- Laboratorio de Neuroanatomía, Departamento de Anatomía, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330023, Chile; Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 8330023, Chile
| | - José Antonio Fuentealba
- Laboratorio de Neuroquímica, Departamento de Farmacia, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago 7820244, Chile; Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 8330023, Chile.
| |
Collapse
|
38
|
Field M, Lukacs IP, Hunter E, Stacey R, Plaha P, Livermore L, Ansorge O, Somogyi P. Tonic GABA A Receptor-Mediated Currents of Human Cortical GABAergic Interneurons Vary Amongst Cell Types. J Neurosci 2021; 41:9702-9719. [PMID: 34667071 PMCID: PMC8612645 DOI: 10.1523/jneurosci.0175-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 12/03/2022] Open
Abstract
Persistent anion conductances through GABAA receptors (GABAARs) are important modulators of neuronal excitability. However, it is currently unknown how the amplitudes of these currents vary among different cell types in the human neocortex, particularly among diverse GABAergic interneurons. We have recorded 101 interneurons in and near layer 1 from cortical tissue surgically resected from both male and female patients, visualized 84 of them and measured tonic GABAAR currents in 48 cells with an intracellular [Cl-] of 65 mm and in the presence of 5 μm GABA. We compare these tonic currents among five groups of interneurons divided by firing properties and four types of interneuron defined by axonal distributions; rosehip, neurogliaform, stalked-bouton, layer 2-3 innervating and a pool of other cells. Interestingly, the rosehip cell, a type of interneuron only described thus far in human tissue, and layer 2-3 innervating cells exhibit larger tonic currents than other layer 1 interneurons, such as neurogliaform and stalked-bouton cells; the latter two groups showing no difference. The positive allosteric modulators of GABAARs allopregnanolone and DS2 also induced larger current shifts in the rosehip and layer 2-3 innervating cells, consistent with higher expression of the δ subunit of the GABAAR in these neurons. We have also examined how patient parameters, such as age, seizures, type of cancer and anticonvulsant treatment may alter tonic inhibitory currents in human neurons. The cell type-specific differences in tonic inhibitory currents could potentially be used to selectively modulate cortical circuitry.SIGNIFICANCE STATEMENT Tonic currents through GABAA receptors (GABAARs) are a potential therapeutic target for a number of neurologic and psychiatric conditions. Here, we show that these currents in human cerebral cortical GABAergic neurons display cell type-specific differences in their amplitudes which implies differential modulation of their excitability. Additionally, we examine whether the amplitudes of the tonic currents measured in our study show any differences between patient populations, finding some evidence that age, seizures, type of cancer, and anticonvulsant treatment may alter tonic inhibition in human tissue. These results advance our understanding of how pathology affects neuronal excitability and could potentially be used to selectively modulate cortical circuitry.
Collapse
Affiliation(s)
- Martin Field
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Istvan P Lukacs
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Emily Hunter
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| | - Richard Stacey
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, United Kingdom
| | - Puneet Plaha
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, United Kingdom
| | - Laurent Livermore
- Department of Neurosurgery, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, United Kingdom
| | - Olaf Ansorge
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom
| |
Collapse
|
39
|
Della Vecchia A, Arone A, Piccinni A, Mucci F, Marazziti D. GABA System in Depression: Impact on Pathophysiology and Psychopharmacology. Curr Med Chem 2021; 29:5710-5730. [PMID: 34781862 DOI: 10.2174/0929867328666211115124149] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/21/2021] [Accepted: 09/30/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The pathophysiology of major depressive disorder (MDD), one of the major causes of worldwide disability, is still largely unclear, despite the increasing data reporting evidence of multiple alterations of different systems. Recently, there was a renewed interest in the signalling of gamma aminobutyric acid (GABA) - the main inhibitory neurotransmitter. OBJECTIVE The aim of this study was to review and comment on the available literature about the involvement of GABA in MDD, as well as on novel GABAergic compounds possibly useful as antidepressants. METHODS We carried out a narrative review through Pubmed, Google Scholar and Scopus, by using specific keywords. RESULTS The results, derived from various research tools, strongly support the presence of a deficiency of the GABA system in MDD, which appears to be restored by common antidepressant treatments. More recent publications would indicate the complex interactions between GABA and all the other processes involved in MDD, such as monoamine neurotransmission, hypothalamus-pituitary adrenal axis functioning, neurotrophism, and immune response. Taken together, all these findings seem to further support the complexity of the pathophysiology of MDD, possibly reflecting the heterogeneity of the clinical pictures. CONCLUSION Although further data are necessary to support the specificity of GABA deficiency in MDD, the available findings would suggest that novel GABAergic compounds might constitute innovative therapeutic strategies in MDD.
Collapse
Affiliation(s)
- Alessandra Della Vecchia
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa. Italy
| | - Alessandro Arone
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa. Italy
| | - Armando Piccinni
- Saint Camillus International University of Health and Medical Sciences, Rome. Italy
| | - Federico Mucci
- Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena. Italy
| | - Donatella Marazziti
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa. Italy
| |
Collapse
|
40
|
Macha A, Liebsch F, Fricke S, Hetsch F, Neuser F, Johannes L, Kress V, Djémié T, Santamaria-Araujo JA, Vilain C, Aeby A, Van Bogaert P, Dejanovic B, Weckhuysen S, Meier JC, Schwarz G. Bi-allelic gephyrin variants impair GABAergic inhibition in a patient with epileptic encephalopathy. Hum Mol Genet 2021; 31:901-913. [PMID: 34617111 DOI: 10.1093/hmg/ddab298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 09/10/2021] [Accepted: 09/22/2021] [Indexed: 11/12/2022] Open
Abstract
Synaptic inhibition is essential for shaping the dynamics of neuronal networks, and aberrant inhibition is linked to epilepsy. Gephyrin (Geph) is the principal scaffolding protein at inhibitory synapses and is essential for postsynaptic clustering of glycine (GlyRs) and GABA type A receptors (GABAARs). Consequently, gephyrin is crucial for maintaining the relationship between excitation and inhibition in normal brain function and mutations in the gephyrin gene (GPHN) are associated with neurodevelopmental disorders and epilepsy. We identified bi-allelic variants in the GPHN gene, namely the missense mutation c.1264G > A and splice acceptor variant c.1315-2A > G, in a patient with developmental and epileptic encephalopathy (DEE). We demonstrate that the splice acceptor variant leads to nonsense-mediated mRNA decay (NMD). Furthermore, the missense variant (D422N) alters gephyrin structure, as examined by analytical size exclusion chromatography and CD-spectroscopy, thus leading to reduced receptor clustering and sensitivity towards calpain-mediated cleavage. Additionally, both alterations contribute to an observed reduction of inhibitory signal transmission in neurons, which likely contributes to the pathological encephalopathy.
Collapse
Affiliation(s)
- Arthur Macha
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Filip Liebsch
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Steffen Fricke
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany.,Institute for Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Florian Hetsch
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Franziska Neuser
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Lena Johannes
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Vanessa Kress
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Tania Djémié
- Applied & Translational Neurogenomics Group, VIB-Center for Molecular Genetics, VIB, Antwerp, Belgium
| | - Jose A Santamaria-Araujo
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Catheline Vilain
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium.,Department of Genetics, Hôpital Erasme, ULB Center of Human Genetics, Université Libre de Bruxelles, Brussels, Belgium.,Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles, Brussels, Belgium
| | - Alec Aeby
- Pediatric Neurology, Queen Fabiola Children Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Patrick Van Bogaert
- Departement of Pediatric Neurology, CHU d'Angers, and Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d'Angers, France
| | - Borislav Dejanovic
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany
| | - Sarah Weckhuysen
- Applied & Translational Neurogenomics Group, VIB-Center for Molecular Genetics, VIB, Antwerp, Belgium.,Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp, Belgium.,Neurology Department, University Hospital Antwerp, Antwerp, Belgium
| | - Jochen C Meier
- Division Cell Physiology, Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Guenter Schwarz
- Institute of Biochemistry, Department of Chemistry, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| |
Collapse
|
41
|
Shibata M, Pattabiraman K, Muchnik SK, Kaur N, Morozov YM, Cheng X, Waxman SG, Sestan N. Hominini-specific regulation of CBLN2 increases prefrontal spinogenesis. Nature 2021; 598:489-494. [PMID: 34599306 PMCID: PMC9018127 DOI: 10.1038/s41586-021-03952-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 08/25/2021] [Indexed: 02/08/2023]
Abstract
The similarities and differences between nervous systems of various species result from developmental constraints and specific adaptations1-4. Comparative analyses of the prefrontal cortex (PFC), a cerebral cortex region involved in higher-order cognition and complex social behaviours, have identified true and potential human-specific structural and molecular specializations4-8, such as an exaggerated PFC-enriched anterior-posterior dendritic spine density gradient5. These changes are probably mediated by divergence in spatiotemporal gene regulation9-17, which is particularly prominent in the midfetal human cortex15,18-20. Here we analysed human and macaque transcriptomic data15,20 and identified a transient PFC-enriched and laminar-specific upregulation of cerebellin 2 (CBLN2), a neurexin (NRXN) and glutamate receptor-δ GRID/GluD-associated synaptic organizer21-27, during midfetal development that coincided with the initiation of synaptogenesis. Moreover, we found that species differences in level of expression and laminar distribution of CBLN2 are, at least in part, due to Hominini-specific deletions containing SOX5-binding sites within a retinoic acid-responsive CBLN2 enhancer. In situ genetic humanization of the mouse Cbln2 enhancer drives increased and ectopic laminar Cbln2 expression and promotes PFC dendritic spine formation. These findings suggest a genetic and molecular basis for the anterior-posterior cortical gradient and disproportionate increase in the Hominini PFC of dendritic spines and a developmental mechanism that may link dysfunction of the NRXN-GRID-CBLN2 complex to the pathogenesis of neuropsychiatric disorders.
Collapse
Affiliation(s)
- Mikihito Shibata
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Kartik Pattabiraman
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
- Yale Child Study Center, New Haven, CT, USA
| | - Sydney K Muchnik
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Navjot Kaur
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Yury M Morozov
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Xiaoyang Cheng
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare Center, West Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, USA
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare Center, West Haven, CT, USA
| | - Nenad Sestan
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, USA.
- Yale Child Study Center, New Haven, CT, USA.
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA.
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA.
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.
- Program in Cellular Neuroscience, Neurodegeneration and Repair, New Haven, CT, USA.
- Kavli Institute for Neuroscience, Yale University, New Haven, CT, USA.
| |
Collapse
|
42
|
Kuljis DA, Micheva KD, Ray A, Wegner W, Bowman R, Madison DV, Willig KI, Barth AL. Gephyrin-Lacking PV Synapses on Neocortical Pyramidal Neurons. Int J Mol Sci 2021; 22:ijms221810032. [PMID: 34576197 PMCID: PMC8467468 DOI: 10.3390/ijms221810032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 11/26/2022] Open
Abstract
Gephyrin has long been thought of as a master regulator for inhibitory synapses, acting as a scaffold to organize γ-aminobutyric acid type A receptors (GABAARs) at the post-synaptic density. Accordingly, gephyrin immunostaining has been used as an indicator of inhibitory synapses; despite this, the pan-synaptic localization of gephyrin to specific classes of inhibitory synapses has not been demonstrated. Genetically encoded fibronectin intrabodies generated with mRNA display (FingRs) against gephyrin (Gephyrin.FingR) reliably label endogenous gephyrin, and can be tagged with fluorophores for comprehensive synaptic quantitation and monitoring. Here we investigated input- and target-specific localization of gephyrin at a defined class of inhibitory synapse, using Gephyrin.FingR proteins tagged with EGFP in brain tissue from transgenic mice. Parvalbumin-expressing (PV) neuron presynaptic boutons labeled using Cre- dependent synaptophysin-tdTomato were aligned with postsynaptic Gephyrin.FingR puncta. We discovered that more than one-third of PV boutons adjacent to neocortical pyramidal (Pyr) cell somas lack postsynaptic gephyrin labeling. This finding was confirmed using correlative fluorescence and electron microscopy. Our findings suggest some inhibitory synapses may lack gephyrin. Gephyrin-lacking synapses may play an important role in dynamically regulating cell activity under different physiological conditions.
Collapse
Affiliation(s)
- Dika A. Kuljis
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Kristina D. Micheva
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; (K.D.M.); (D.V.M.)
| | - Ajit Ray
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Waja Wegner
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, Germany; (W.W.); (K.I.W.)
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Ryan Bowman
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
| | - Daniel V. Madison
- Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; (K.D.M.); (D.V.M.)
| | - Katrin I. Willig
- Optical Nanoscopy in Neuroscience, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, 37075 Göttingen, Germany; (W.W.); (K.I.W.)
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Alison L. Barth
- Center for the Neural Basis of Cognition, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA; (D.A.K.); (A.R.); (R.B.)
- Correspondence: ; Tel.: +1-412-268-1198
| |
Collapse
|
43
|
Belelli D, Hales TG, Lambert JJ, Luscher B, Olsen R, Peters JA, Rudolph U, Sieghart W. GABA A receptors in GtoPdb v.2021.3. IUPHAR/BPS GUIDE TO PHARMACOLOGY CITE 2021; 2021. [PMID: 35005623 DOI: 10.2218/gtopdb/f72/2021.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The GABAA receptor is a ligand-gated ion channel of the Cys-loop family that includes the nicotinic acetylcholine, 5-HT3 and strychnine-sensitive glycine receptors. GABAA receptor-mediated inhibition within the CNS occurs by fast synaptic transmission, sustained tonic inhibition and temporally intermediate events that have been termed 'GABAA, slow' [45]. GABAA receptors exist as pentamers of 4TM subunits that form an intrinsic anion selective channel. Sequences of six α, three β, three γ, one δ, three ρ, one ε, one π and one θ GABAA receptor subunits have been reported in mammals [278, 235, 236, 283]. The π-subunit is restricted to reproductive tissue. Alternatively spliced versions of many subunits exist (e.g. α4- and α6- (both not functional) α5-, β2-, β3- and γ2), along with RNA editing of the α3 subunit [71]. The three ρ-subunits, (ρ1-3) function as either homo- or hetero-oligomeric assemblies [359, 50]. Receptors formed from ρ-subunits, because of their distinctive pharmacology that includes insensitivity to bicuculline, benzodiazepines and barbiturates, have sometimes been termed GABAC receptors [359], but they are classified as GABA A receptors by NC-IUPHAR on the basis of structural and functional criteria [16, 235, 236]. Many GABAA receptor subtypes contain α-, β- and γ-subunits with the likely stoichiometry 2α.2β.1γ [168, 235]. It is thought that the majority of GABAA receptors harbour a single type of α- and β - subunit variant. The α1β2γ2 hetero-oligomer constitutes the largest population of GABAA receptors in the CNS, followed by the α2β3γ2 and α3β3γ2 isoforms. Receptors that incorporate the α4- α5-or α 6-subunit, or the β1-, γ1-, γ3-, δ-, ε- and θ-subunits, are less numerous, but they may nonetheless serve important functions. For example, extrasynaptically located receptors that contain α6- and δ-subunits in cerebellar granule cells, or an α4- and δ-subunit in dentate gyrus granule cells and thalamic neurones, mediate a tonic current that is important for neuronal excitability in response to ambient concentrations of GABA [209, 272, 83, 19, 288]. GABA binding occurs at the β+/α- subunit interface and the homologous γ+/α- subunits interface creates the benzodiazepine site. A second site for benzodiazepine binding has recently been postulated to occur at the α+/β- interface ([254]; reviewed by [282]). The particular α-and γ-subunit isoforms exhibit marked effects on recognition and/or efficacy at the benzodiazepine site. Thus, receptors incorporating either α4- or α6-subunits are not recognised by 'classical' benzodiazepines, such as flunitrazepam (but see [356]). The trafficking, cell surface expression, internalisation and function of GABAA receptors and their subunits are discussed in detail in several recent reviews [52, 140, 188, 316] but one point worthy of note is that receptors incorporating the γ2 subunit (except when associated with α5) cluster at the postsynaptic membrane (but may distribute dynamically between synaptic and extrasynaptic locations), whereas as those incorporating the δ subunit appear to be exclusively extrasynaptic. NC-IUPHAR [16, 235, 3, 2] class the GABAA receptors according to their subunit structure, pharmacology and receptor function. Currently, eleven native GABAA receptors are classed as conclusively identified (i.e., α1β2γ2, α1βγ2, α3βγ2, α4βγ2, α4β2δ, α4β3δ, α5βγ2, α6βγ2, α6β2δ, α6β3δ and ρ) with further receptor isoforms occurring with high probability, or only tentatively [235, 236]. It is beyond the scope of this Guide to discuss the pharmacology of individual GABAA receptor isoforms in detail; such information can be gleaned in the reviews [16, 95, 168, 173, 143, 278, 216, 235, 236] and [9, 10]. Agents that discriminate between α-subunit isoforms are noted in the table and additional agents that demonstrate selectivity between receptor isoforms, for example via β-subunit selectivity, are indicated in the text below. The distinctive agonist and antagonist pharmacology of ρ receptors is summarised in the table and additional aspects are reviewed in [359, 50, 145, 223]. Several high-resolution cryo-electron microscopy structures have been described in which the full-length human α1β3γ2L GABAA receptor in lipid nanodiscs is bound to the channel-blocker picrotoxin, the competitive antagonist bicuculline, the agonist GABA (γ-aminobutyric acid), and the classical benzodiazepines alprazolam and diazepam [198].
Collapse
|
44
|
Dávila-Bouziguet E, Casòliba-Melich A, Targa-Fabra G, Galera-López L, Ozaita A, Maldonado R, Ávila J, Delgado-García JM, Gruart A, Soriano E, Pascual M. Functional protection in J20/VLW mice: a model of non-demented with Alzheimer's disease neuropathology. Brain 2021; 145:729-743. [PMID: 34424282 DOI: 10.1093/brain/awab319] [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: 02/05/2021] [Revised: 06/19/2021] [Accepted: 07/28/2021] [Indexed: 11/15/2022] Open
Abstract
Alzheimer's disease comprises amyloid-β and hyperphosphorylated Tau accumulation, imbalanced neuronal activity, aberrant oscillatory rhythms, and cognitive deficits. Non-Demented with Alzheimer's disease Neuropathology (NDAN) defines a novel clinical entity with amyloid-β and Tau pathologies but preserved cognition. The mechanisms underlying such neuroprotection remain undetermined and animal models of NDAN are currently unavailable. We demonstrate that J20/VLW mice (accumulating amyloid-β and hyperphosphorylated Tau) exhibit preserved hippocampal rhythmic activity and cognition, as opposed to J20 and VLW animals, which show significant alterations. Furthermore, we show that the overexpression of mutant human Tau in coexistence with amyloid-β accumulation renders a particular hyperphosphorylated Tau signature in hippocampal interneurons. The GABAergic septohippocampal pathway, responsible for hippocampal rhythmic activity, is preserved in J20/VLW mice, in contrast to single mutants. Our data highlight J20/VLW mice as a suitable animal model in which to explore the mechanisms driving cognitive preservation in NDAN. Moreover, they suggest that a differential Tau phosphorylation pattern in hippocampal interneurons prevents the loss of GABAergic septohippocampal innervation and alterations in local field potentials, thereby avoiding cognitive deficits.
Collapse
Affiliation(s)
- Eva Dávila-Bouziguet
- Department of Cell Biology, Physiology and Immunology, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Spain
| | - Arnau Casòliba-Melich
- Department of Cell Biology, Physiology and Immunology, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Spain
| | - Georgina Targa-Fabra
- Department of Cell Biology, Physiology and Immunology, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Spain
| | - Lorena Galera-López
- Laboratory of Neuropharmacology-NeuroPhar, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Andrés Ozaita
- Laboratory of Neuropharmacology-NeuroPhar, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology-NeuroPhar, Department of Experimental and Health Sciences, Pompeu Fabra University, Barcelona, Spain
| | - Jesús Ávila
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Spain.,Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Neurobiology Laboratory, Madrid, Spain
| | - José M Delgado-García
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Neurobiology Laboratory, Madrid, Spain.,Division of Neurosciences, Pablo de Olavide University, Seville, Spain
| | - Agnès Gruart
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Neurobiology Laboratory, Madrid, Spain.,Division of Neurosciences, Pablo de Olavide University, Seville, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Spain
| | - Marta Pascual
- Department of Cell Biology, Physiology and Immunology, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED, ISCIII), Spain
| |
Collapse
|
45
|
Ghit A, Assal D, Al-Shami AS, Hussein DEE. GABA A receptors: structure, function, pharmacology, and related disorders. J Genet Eng Biotechnol 2021; 19:123. [PMID: 34417930 PMCID: PMC8380214 DOI: 10.1186/s43141-021-00224-0] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/08/2021] [Indexed: 02/03/2023]
Abstract
Background γ-Aminobutyric acid sub-type A receptors (GABAARs) are the most prominent inhibitory neurotransmitter receptors in the CNS. They are a family of ligand-gated ion channel with significant physiological and therapeutic implications. Main body GABAARs are heteropentamers formed from a selection of 19 subunits: six α (alpha1-6), three β (beta1-3), three γ (gamma1-3), three ρ (rho1-3), and one each of the δ (delta), ε (epsilon), π (pi), and θ (theta) which result in the production of a considerable number of receptor isoforms. Each isoform exhibits distinct pharmacological and physiological properties. However, the majority of GABAARs are composed of two α subunits, two β subunits, and one γ subunit arranged as γ2β2α1β2α1 counterclockwise around the center. The mature receptor has a central chloride ion channel gated by GABA neurotransmitter and modulated by a variety of different drugs. Changes in GABA synthesis or release may have a significant effect on normal brain function. Furthermore, The molecular interactions and pharmacological effects caused by drugs are extremely complex. This is due to the structural heterogeneity of the receptors, and the existence of multiple allosteric binding sites as well as a wide range of ligands that can bind to them. Notably, dysfunction of the GABAergic system contributes to the development of several diseases. Therefore, understanding the relationship between GABAA receptor deficits and CNS disorders thus has a significant impact on the discovery of disease pathogenesis and drug development. Conclusion To date, few reviews have discussed GABAA receptors in detail. Accordingly, this review aims to summarize the current understanding of the structural, physiological, and pharmacological properties of GABAARs, as well as shedding light on the most common associated disorders.
Collapse
Affiliation(s)
- Amr Ghit
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy. .,Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.
| | - Dina Assal
- Department of Biotechnology, American University in Cairo (AUC), Cairo, Egypt
| | - Ahmed S Al-Shami
- Department of Biotechnology, Institute of Graduate Studies and Research (IGSR), Alexandria University, Alexandria, Egypt.,Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Diaa Eldin E Hussein
- Animal Health Research Institute (AHRI), Agricultural Research Center (ARC), Port of Alexandria, Alexandria, Egypt
| |
Collapse
|
46
|
Lombardi JP, Kinzlmaier DA, Jacob TC. Visualizing GABA A Receptor Trafficking Dynamics with Fluorogenic Protein Labeling. ACTA ACUST UNITED AC 2021; 92:e97. [PMID: 32364672 DOI: 10.1002/cpns.97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is increasingly evident that neurotransmitter receptors, including ionotropic GABA A receptors (GABAARs), exhibit highly dynamic trafficking and cell surface mobility. Regulated trafficking to and from the surface is a critical determinant of GABAAR neurotransmission. Receptors delivered by exocytosis diffuse laterally in the plasma membrane, with tethering and reduced movement at synapses occurring through receptor interactions with the subsynaptic scaffold. After diffusion away from synapses, receptors are internalized by clathrin-dependent endocytosis at extrasynaptic sites and can be either recycled back to the cell membrane or degraded in lysosomes. To study the dynamics of these key trafficking events in neurons, we have developed novel optical methods based around receptors containing a dual-tagged γ2 subunit (γ2pHFAP) in combination with fluorogen dyes. Specifically, the GABAAR γ2 subunit is tagged with a pH-sensitive green fluorescent protein and a fluorogen-activating peptide (FAP). The FAP allows receptor labeling with fluorogen dyes that are optically silent until bound to the FAP. Combining FAP and fluorescent imaging with organelle labeling allows novel and accurate measurement of receptor turnover and accumulation into intracellular compartments under basal conditions in scenarios ranging from in vitro seizure models to drug exposure paradigms. Here we provide a protocol to track and quantify receptors in transit from the neuronal surface to endosomes and lysosomes. This protocol is readily applicable to cell lines and primary cells, allowing rapid quantitative measurements of receptor surface levels and postendocytic trafficking decisions. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Preparation of cortical neuronal cultures for imaging assays Basic Protocol 2: Surface receptor internalization and trafficking to early endosomes Basic Protocol 3: Measurement of receptor steady state surface level, synaptic level, and lysosomal targeting.
Collapse
Affiliation(s)
- Jacob P Lombardi
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - David A Kinzlmaier
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| |
Collapse
|
47
|
Electrophysiology of ionotropic GABA receptors. Cell Mol Life Sci 2021; 78:5341-5370. [PMID: 34061215 PMCID: PMC8257536 DOI: 10.1007/s00018-021-03846-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/02/2021] [Accepted: 04/23/2021] [Indexed: 10/30/2022]
Abstract
GABAA receptors are ligand-gated chloride channels and ionotropic receptors of GABA, the main inhibitory neurotransmitter in vertebrates. In this review, we discuss the major and diverse roles GABAA receptors play in the regulation of neuronal communication and the functioning of the brain. GABAA receptors have complex electrophysiological properties that enable them to mediate different types of currents such as phasic and tonic inhibitory currents. Their activity is finely regulated by membrane voltage, phosphorylation and several ions. GABAA receptors are pentameric and are assembled from a diverse set of subunits. They are subdivided into numerous subtypes, which differ widely in expression patterns, distribution and electrical activity. Substantial variations in macroscopic neural behavior can emerge from minor differences in structure and molecular activity between subtypes. Therefore, the diversity of GABAA receptors widens the neuronal repertoire of responses to external signals and contributes to shaping the electrical activity of neurons and other cell types.
Collapse
|
48
|
Neocortex- and hippocampus-specific deletion of Gabrg2 causes temperature-dependent seizures in mice. Cell Death Dis 2021; 12:553. [PMID: 34050134 PMCID: PMC8163876 DOI: 10.1038/s41419-021-03846-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/17/2021] [Indexed: 02/04/2023]
Abstract
Mutations in the GABRG2 gene encoding the γ-aminobutyric acid (GABA) A receptor gamma 2 subunit are associated with genetic epilepsy with febrile seizures plus, febrile seizures plus, febrile seizures, and other symptoms of epilepsy. However, the mechanisms underlying Gabrg2-mediated febrile seizures are poorly understood. Here, we used the Cre/loxP system to generate conditional knockout (CKO) mice with deficient Gabrg2 in the hippocampus and neocortex. Heterozygous CKO mice (Gabrg2fl/wtCre+) exhibited temperature-dependent myoclonic jerks, generalised tonic-clonic seizures, increased anxiety-like symptoms, and a predisposition to induce seizures. Cortical electroencephalography showed the hyperexcitability in response to temperature elevation in Gabrg2fl/wtCre+ mice, but not in wild-type mice. Gabrg2fl/wtCre+ mice exhibited spontaneous seizures and susceptibility to temperature-induced seizures. Loss of neurons were observed in cortical layers V-VI and hippocampus of Gabrg2fl/wtCre+ mice. Furthermore, the latency of temperature- or pentylenetetrazol-induced seizures were significantly decreased in Gabrg2fl/wtCre+ mice compared with wild-type mice. In summary, Gabrg2fl/wtCre+ mice with Gabrg2 deletion in the neocortex and hippocampus reproduce many features of febrile seizures and therefore provide a novel model to further understand this syndrome at the cellular and molecular level.
Collapse
|
49
|
Yang X, Ding H, Wei H, Liu J, Liao P, Zhang Y, Wang X, Chi X. Association between GABRG2 rs211037 polymorphism and idiopathic generalized epilepsies: a meta-analysis. ACTA EPILEPTOLOGICA 2021. [DOI: 10.1186/s42494-021-00043-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Abstract
Background
We performed this meta-analysis to investigate the association between GABRG2 rs211037polymorphism and the risk for idiopathic generalized epilepsies (IGEs).
Methods
Medline, Embase, Cochrane Library and Chinese National Knowledge Infrastructure (CNKI) databases were searched for eligible studies (until May 5, 2020) on the association between GABRG2 rs211037 polymorphism and IGE. The odds ratios were calculated using a fixed or random model in STATA 15.0 software. Subgroup analyses for ethnicity, age, source of controls, type of seizure syndrome and therapeutic responses were conducted.
Results
We found no significant associations between GABRG2 rs211037 polymorphism and the susceptibility to IGEs. In addition, no significant association was detected between GABRG2 rs211037 polymorphism and drug resistance in IGE patients. The results did not change after stratification by Asian population, healthy controls, children, juvenile myoclonic epilepsy, and childhood absence epilepsy.
Conclusion
The current studies indicated that the GABRG2 rs211037 polymorphism was not related to susceptibility or drug resistance of IGE. Further well-designed studies are needed to verify the results.
Collapse
|
50
|
Maingret F, Groc L. Characterization of the Functional Cross-Talk between Surface GABA A and Dopamine D5 Receptors. Int J Mol Sci 2021; 22:4867. [PMID: 34064454 PMCID: PMC8125140 DOI: 10.3390/ijms22094867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 01/17/2023] Open
Abstract
The γ-aminobutyric acid type A receptor (GABAAR) plays a major role in fast inhibitory synaptic transmission and is highly regulated by the neuromodulator dopamine. In this aspect, most of the attention has been focused on the classical intracellular signaling cascades following dopamine G-protein-coupled receptor activation. Interestingly, the GABAAR and dopamine D5 receptor (D5R) have been shown to physically interact in the hippocampus, but whether a functional cross-talk occurs is still debated. In the present study, we use a combination of imaging and single nanoparticle tracking in live hippocampal neurons to provide evidence that GABAARs and D5Rs form dynamic surface clusters. Disrupting the GABAAR-D5R interaction with a competing peptide leads to an increase in the diffusion coefficient and the explored area of both receptors, and a drop in immobile synaptic GABAARs. By means of patch-clamp recordings, we show that this fast lateral redistribution of surface GABAARs correlates with a robust depression in the evoked GABAergic currents. Strikingly, it also shifts in time the expression of long-term potentiation at glutamatergic synapses. Together, our data both set the plasma membrane as the primary stage of a functional interplay between GABAAR and D5R, and uncover a non-canonical role in regulating synaptic transmission.
Collapse
Affiliation(s)
- François Maingret
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, UMR 5297, 33076 Bordeaux, France;
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33076 Bordeaux, France
| | - Laurent Groc
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, UMR 5297, 33076 Bordeaux, France;
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33076 Bordeaux, France
| |
Collapse
|