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Goldschen-Ohm MP. Benzodiazepine Modulation of GABA A Receptors: A Mechanistic Perspective. Biomolecules 2022; 12:biom12121784. [PMID: 36551212 PMCID: PMC9775625 DOI: 10.3390/biom12121784] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/23/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
Benzodiazepines (BZDs) are a class of widely prescribed psychotropic drugs that target GABAA receptors (GABAARs) to tune inhibitory synaptic signaling throughout the central nervous system. Despite knowing their molecular target for over 40 years, we still do not fully understand the mechanism of modulation at the level of the channel protein. Nonetheless, functional studies, together with recent cryo-EM structures of GABAA(α1)2(βX)2(γ2)1 receptors in complex with BZDs, provide a wealth of information to aid in addressing this gap in knowledge. Here, mechanistic interpretations of functional and structural evidence for the action of BZDs at GABAA(α1)2(βX)2(γ2)1 receptors are reviewed. The goal is not to describe each of the many studies that are relevant to this discussion nor to dissect in detail all the effects of individual mutations or perturbations but rather to highlight general mechanistic principles in the context of recent structural information.
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Crocetti L, Guerrini G, Melani F, Vergelli C, Mascia MP, Giovannoni MP. GABA A Receptor Modulators with a Pyrazolo[1,5-a]quinazoline Core: Synthesis, Molecular Modelling Studies and Electrophysiological Assays. Int J Mol Sci 2022; 23:13032. [PMID: 36361842 PMCID: PMC9658275 DOI: 10.3390/ijms232113032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/21/2022] [Accepted: 10/25/2022] [Indexed: 08/06/2023] Open
Abstract
As a continuation of our study in the GABAA receptor modulators field, we report the design and synthesis of new 8-chloropyrazolo[1,5-a]quinazoline derivatives. Molecular docking studies and the evaluation of the 'Proximity Frequencies' (exploiting our reported model) were performed on all the final compounds (3, 4, 6a-c, 7a,b, 8, 9, 12a-c, 13a,b, 14-19) to predict their profile on the α1β2γ2-GABAAR subtype. Furthermore, to verify whether the information coming from this virtual model was valid and, at the same time, to complete the study on this series, we evaluated the effects of compounds (1-100 µM) on the modulation of GABAA receptor function through electrophysiological techniques on recombinant α1β2γ2L-GABAA receptors expressed in Xenopus laevis oocytes. The matching between the virtual prediction and the electrophysiological tests makes our model a useful tool for the study of GABAA receptor modulators.
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Affiliation(s)
- Letizia Crocetti
- Neurofarba, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Gabriella Guerrini
- Neurofarba, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Fabrizio Melani
- Neurofarba, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Claudia Vergelli
- Neurofarba, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Maria Paola Mascia
- CNR-Institute of Neuroscience, Cagliari, Cittadella Universitaria, 09042 Monserrato, Italy
| | - Maria Paola Giovannoni
- Neurofarba, Pharmaceutical and Nutraceutical Section, University of Florence, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
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Carton L, Auger F, Laloux C, Durieux N, Kyheng M, Potey C, Bergeron S, Rolland B, Deguil J, Bordet R. Effects of acute ethanol and/or diazepam exposure on immediate and delayed hippocampal metabolite levels in rats anesthetized with isoflurane. Fundam Clin Pharmacol 2022; 36:687-698. [DOI: 10.1111/fcp.12764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 01/13/2022] [Accepted: 01/31/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Louise Carton
- Univ. Lille, Inserm, CHU Lille, Lille Neuroscience and Cognition, Degenerative and Vascular Cognitive Disorders, UMR‐S1172, Pharmacology Department Lille France
| | - Florent Auger
- Lille In vivo Imaging and Functional Exploration platform Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41‐UMS 2014‐PLBS Lille France
| | - Charlotte Laloux
- Lille In vivo Imaging and Functional Exploration platform Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41‐UMS 2014‐PLBS Lille France
| | - Nicolas Durieux
- Lille In vivo Imaging and Functional Exploration platform Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, US 41‐UMS 2014‐PLBS Lille France
| | - Maéva Kyheng
- ULR 2694‐METRICS: Évaluation des Technologies de Santé et des Pratiques Médicales Univ. Lille, CHU Lille Lille France
- Département de Biostatistiques CHU Lille Lille France
| | - Camille Potey
- Univ. Lille, Inserm, CHU Lille, Lille Neuroscience and Cognition, Degenerative and Vascular Cognitive Disorders, UMR‐S1172, Pharmacology Department Lille France
| | - Sandrine Bergeron
- Univ. Lille, Inserm, CHU Lille, Lille Neuroscience and Cognition, Degenerative and Vascular Cognitive Disorders, UMR‐S1172, Pharmacology Department Lille France
| | - Benjamin Rolland
- Service Universitaire d'Addictologie de Lyon CH Le Vinatier, Hospices Civils de Lyon Bron France
- Inserm U1028, CNRS UMR5292 Université Claude Bernard Lyon 1 Bron France
| | - Julie Deguil
- Univ. Lille, Inserm, CHU Lille, Lille Neuroscience and Cognition, Degenerative and Vascular Cognitive Disorders, UMR‐S1172, Pharmacology Department Lille France
| | - Régis Bordet
- Univ. Lille, Inserm, CHU Lille, Lille Neuroscience and Cognition, Degenerative and Vascular Cognitive Disorders, UMR‐S1172, Pharmacology Department Lille France
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Wang S, Zhang X, Zhou L, Wu Q, Han Y. Analysis of GABRG2 C588T polymorphism in genetic epilepsy and evaluation of GABRG2 in drug treatment. Clin Transl Sci 2021; 14:1725-1733. [PMID: 33650258 PMCID: PMC8504831 DOI: 10.1111/cts.12997] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 01/11/2023] Open
Abstract
Epilepsy is a common disorder with complex inheritance, and its treatment is very unsatisfactory. An association between the GABRG2 C588T polymorphism and genetic generalized epilepsy has been studied by several genetic association studies. However, these results were inconsistent, and the role of GABRG2 in epilepsy treatment remains unknown. To evaluate the role of GABRG2 in epilepsy, we performed meta-analysis, expression quantitative trait loci analysis, protein-protein interaction analysis, and drug-gene interaction analysis. The combined results indicated that the GABRG2 C588T polymorphism was associated with genetic generalized epilepsy risk under dominant and allelic models (odds ratio [OR] = 1.25, 95% confidence interval [CI] = 1.02-1.54, p = 0.03, I2 = 0% and OR = 1.21, 95% CI = 1.03-1.42, p = 0.02, I2 = 20%, respectively). In the Asian population, we also found similar results under dominant and allelic models (OR = 1.93, 95% CI = 1.18-3.16, p = 0.009, I2 = 0% and OR = 1.69, 95% CI = 1.20-2.37, p = 0.003, I2 = 11%, respectively). We first found that the GABRG2 C588T polymorphism regulates GABRG2 expression in human brain tissues and that the protein encoded by GABRG2 interacts with targets of approved antiepileptic drugs (AEDs). Interestingly, we also found that GABRG2 itself interacts with approved AEDs. Taken together, the results indicate that the C588T polymorphism might alter the GABAA receptor by modulating GABRG2 gene expression, resulting in increased risk for epilepsy, and that GABRG2 may be a potential therapeutic target for epilepsy.
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Affiliation(s)
- Shitao Wang
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Xianjun Zhang
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Liang Zhou
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Qian Wu
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
| | - Yanbing Han
- Department of Neurology, The First Affiliated Hospital of Kunming Medical University, Kunming, China
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Markin PA, Brito A, Moskaleva NE, Tagliaro F, Tarasov VV, La Frano MR, Savitskii MV, Appolonova SA. Short- and medium-term exposures of diazepam induce metabolomic alterations associated with the serotonergic, dopaminergic, adrenergic and aspartic acid neurotransmitter systems in zebrafish (Danio rerio) embryos/larvae. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2021; 38:100816. [PMID: 33610025 DOI: 10.1016/j.cbd.2021.100816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Diazepam is a well-known psychoactive drug widely used worldwide for the treatment of anxiety, seizures, alcohol withdrawal syndrome, muscle spasms, sleeplessness, agitation, and pre/post-operative sedation. It is part of the benzodiazepine family, substances known to primarily act by binding and enhancing gamma-aminobutyric acid (GABAA) receptors. The objective of the present work was to investigate the influence of short and medium-term diazepam exposures on neurotransmitters measured through targeted metabolomics using a zebrafish embryo model. METHODS Short-term (2.5 h) and medium-term (96 h) exposures to diazepam were performed at drug concentrations of 0.8, 1.6, 16, and 160 μg/L. Intervention groups were compared with a vehicle control group. Each group consisted of 20 zebrafish eggs/larvae. Metabolites related with neurotransmission were determined by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). RESULTS Thirty-six compounds were quantified. Significantly increased tryptophan and serotonin concentrations were found in the intervention groups receiving higher doses of diazepam in 2.5 h exposure (p < 0.05 control versus intervention groups). Tyrosine concentrations were higher (p < 0.05) at higher concentrations in 2.5 h exposure, but lower (p < 0.05) at higher concentrations in 96 h exposure. Both phenylalanine and aspartic acid concentrations were higher (p < 0.05) at higher doses in 2.5 h and 96 h exposure. CONCLUSIONS Short- and medium-term exposures to diazepam induce dose- and time-dependent metabolomic alterations associated with the serotonergic, dopaminergic/adrenergic, and aspartic acid neurotransmitter systems in zebrafish.
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Affiliation(s)
- Pavel A Markin
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; PhD Program in Nanosciences and Advanced Technologies, University of Verona, Verona, Italy; I.M. Sechenov First Moscow State Medical University, Russia
| | - Alex Brito
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Natalia E Moskaleva
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; World-Class Research Center "Digital Biodesign and Personalized Healthcare", I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Franco Tagliaro
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; Unit of Forensic Medicine, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | | | - Michael R La Frano
- Department of Food Science and Nutrition, California Polytechnic State University, San Luis Obispo, CA, USA; Cal Poly Metabolomics Service Center, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Mark V Savitskii
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; I.M. Sechenov First Moscow State Medical University, Russia
| | - Svetlana A Appolonova
- Laboratory of Pharmacokinetics and Metabolomic Analysis, Institute of Translational Medicine and Biotechnology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
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Nors JW, Gupta S, Goldschen-Ohm MP. A critical residue in the α 1M2-M3 linker regulating mammalian GABA A receptor pore gating by diazepam. eLife 2021; 10:64400. [PMID: 33591271 PMCID: PMC7899671 DOI: 10.7554/elife.64400] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 02/15/2021] [Indexed: 01/29/2023] Open
Abstract
Benzodiazepines (BZDs) are a class of widely prescribed psychotropic drugs that modulate activity of GABAA receptors (GABAARs), neurotransmitter-gated ion channels critical for synaptic transmission. However, the physical basis of this modulation is poorly understood. We explore the role of an important gating domain, the α1M2–M3 linker, in linkage between the BZD site and pore gate. To probe energetics of this coupling without complication from bound agonist, we use a gain of function mutant (α1L9'Tβ2γ2L) directly activated by BZDs. We identify a specific residue whose mutation (α1V279A) more than doubles the energetic contribution of the BZD positive modulator diazepam (DZ) to pore opening and also enhances DZ potentiation of GABA-evoked currents in a wild-type background. In contrast, other linker mutations have little effect on DZ efficiency, but generally impair unliganded pore opening. Our observations reveal an important residue regulating BZD-pore linkage, thereby shedding new light on the molecular mechanism of these drugs.
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Affiliation(s)
- Joseph W Nors
- University of Texas at Austin, Department of Neuroscience, Austin, United States
| | - Shipra Gupta
- University of Texas at Austin, Department of Neuroscience, Austin, United States
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Interaction between GABA A receptor α 1 and β 2 subunits at the N-terminal peripheral regions is crucial for receptor binding and gating. Biochem Pharmacol 2020; 183:114338. [PMID: 33189674 DOI: 10.1016/j.bcp.2020.114338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 01/08/2023]
Abstract
Pentameric ligand gated ion channels (pLGICs) are crucial in electrochemical signaling but exact molecular mechanisms of their activation remain elusive. So far, major effort focused on the top-down molecular pathway between the ligand binding site and the channel gate. However, recent studies revealed that pLGIC activation is associated with coordinated subunit twisting in the membrane plane. This suggests a key role of intersubunit interactions but the underlying mechanisms remain largely unknown. Herein, we investigated a "peripheral" subunit interface region of GABAA receptor where structural modeling indicated interaction between N-terminal α1F14 and β2F31 residues. Our experiments underscored a crucial role of this interaction in ligand binding and gating, especially preactivation and opening, showing that the intersubunit cross-talk taking place outside (above) the top-down pathway can be strongly involved in receptor activation. Thus, described here intersubunit interaction appears to operate across a particularly long distance, affecting vast portions of the macromolecule.
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Troutwine B, Park A, Velez‐Hernandez ME, Lew L, Mihic SJ, Atkinson NS. F654A and K558Q Mutations in NMDA Receptor 1 Affect Ethanol‐Induced Behaviors in Drosophila. Alcohol Clin Exp Res 2019; 43:2480-2493. [DOI: 10.1111/acer.14215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/03/2019] [Indexed: 01/27/2023]
Affiliation(s)
- Benjamin Troutwine
- Department of Neuroscience and Waggoner Center for Alcohol and Addiction Research The University of Texas at Austin Austin Texas
| | - Annie Park
- Department of Neuroscience and Waggoner Center for Alcohol and Addiction Research The University of Texas at Austin Austin Texas
| | | | - Linda Lew
- Department of Neuroscience and Waggoner Center for Alcohol and Addiction Research The University of Texas at Austin Austin Texas
| | - S. John Mihic
- Department of Neuroscience and Waggoner Center for Alcohol and Addiction Research The University of Texas at Austin Austin Texas
| | - Nigel S. Atkinson
- Department of Neuroscience and Waggoner Center for Alcohol and Addiction Research The University of Texas at Austin Austin Texas
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Pflanz NC, Daszkowski AW, James KA, Mihic SJ. Ketone body modulation of ligand-gated ion channels. Neuropharmacology 2018; 148:21-30. [PMID: 30562540 DOI: 10.1016/j.neuropharm.2018.12.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/27/2018] [Accepted: 12/10/2018] [Indexed: 01/01/2023]
Abstract
Ketogenesis is a metabolic process wherein ketone bodies are produced from the breakdown of fatty acids. In humans, fatty acid catabolism results in the production of acetyl-CoA which can then be used to synthesize three ketone bodies: acetoacetate, acetone, and β-hydroxybutyrate. Ketogenesis occurs at a higher rate in situations of low blood glucose, such as during fasting, heavy alcohol consumption, and in situations of low insulin, as well as in individuals who follow a 'ketogenic diet' consisting of low carbohydrate and high fat intake. This diet has various therapeutic indications, including reduction of seizure likelihood in epileptic patients and alcohol withdrawal syndrome. However, the mechanisms underlying these therapeutic benefits are still unclear, with studies suggesting various mechanisms such as a shift in energy production in the brain, effects on neurotransmitter production, or effects on various protein targets. Two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes was used to investigate the actions of ketone bodies on three ionotropic receptors: GABAA, glycine, and NMDA receptors. While physiologically-relevant concentrations of acetone have little effect on inhibitory GABA or glycine receptors, β-hydroxybutyrate inhibits the effects of agonists of these receptors at concentrations achieved in vivo. Additionally, both acetone and β-hydroxybutyrate act as inhibitors of glutamate at the excitatory NMDA receptor. Due to the role of hyperexcitability in the pathogenesis of epilepsy and alcohol withdrawal, the inhibitory actions of acetone and β-hydroxybutyrate at NMDA receptors may underlie the therapeutic benefit of a ketogenic diet for these disorders.
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Affiliation(s)
- Natasha C Pflanz
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol and Addiction Research, Institutes for Neuroscience and Cell and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Anna W Daszkowski
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol and Addiction Research, Institutes for Neuroscience and Cell and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Keith A James
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol and Addiction Research, Institutes for Neuroscience and Cell and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - S John Mihic
- Department of Neuroscience, Division of Pharmacology and Toxicology, Waggoner Center for Alcohol and Addiction Research, Institutes for Neuroscience and Cell and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA.
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