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Germann AL, Xu Y, Covey DF, Evers AS, Akk G. Comparison of Behavioral Effects of GABAergic Low- and High-Efficacy Neuroactive Steroids in the Zebrafish Larvae Assay. ACS Chem Neurosci 2024; 15:909-915. [PMID: 38386612 PMCID: PMC10953468 DOI: 10.1021/acschemneuro.3c00836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024] Open
Abstract
Activation of the GABAA receptor is associated with numerous behavioral end points ranging from anxiolysis to deep anesthesia. The specific behavioral effect of a GABAergic compound is considered to correlate with the degree of its functional effect on the receptor. Here, we tested the hypothesis that a low-efficacy allosteric potentiator of the GABAA receptor may act, due to a ceiling effect, as a sedative with reduced and limited action. We synthesized a derivative, named (3α,5β)-20-methyl-pregnane-3,20-diol (KK-235), of the GABAergic neurosteroid 5β-pregnane-3α,20α-diol. Using electrophysiology, we showed that KK-235 is a low-efficacy potentiator of the synaptic-type α1β2γ2L GABAA receptor. In the zebrafish larvae behavioral assay, KK-235 was found to only partially block the inverted photomotor response (PMR) and to weakly reduce swimming behavior, whereas the high-efficacy GABAergic steroid (3α,5α,17β)-3-hydroxyandrostane-17-carbonitrile (ACN) fully blocked PMR and spontaneous swimming. Coapplication of KK-235 reduced the potentiating effect of ACN in an electrophysiological assay and dampened its sedative effect in behavioral experiments. We propose that low-efficacy GABAergic potentiators may be useful as sedatives with limited action.
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Affiliation(s)
- Allison L. Germann
- Departments of Anesthesiology (ALG, ASE, GA) and Developmental Biology (YX, DFC), and the Taylor Family Institute for Innovative Psychiatric Research (DFC, ASE, GA), Washington University School of Medicine, St Louis, MO 63110, USA
| | - Yuanjian Xu
- Departments of Anesthesiology (ALG, ASE, GA) and Developmental Biology (YX, DFC), and the Taylor Family Institute for Innovative Psychiatric Research (DFC, ASE, GA), Washington University School of Medicine, St Louis, MO 63110, USA
| | - Douglas F. Covey
- Departments of Anesthesiology (ALG, ASE, GA) and Developmental Biology (YX, DFC), and the Taylor Family Institute for Innovative Psychiatric Research (DFC, ASE, GA), Washington University School of Medicine, St Louis, MO 63110, USA
| | - Alex S. Evers
- Departments of Anesthesiology (ALG, ASE, GA) and Developmental Biology (YX, DFC), and the Taylor Family Institute for Innovative Psychiatric Research (DFC, ASE, GA), Washington University School of Medicine, St Louis, MO 63110, USA
| | - Gustav Akk
- Departments of Anesthesiology (ALG, ASE, GA) and Developmental Biology (YX, DFC), and the Taylor Family Institute for Innovative Psychiatric Research (DFC, ASE, GA), Washington University School of Medicine, St Louis, MO 63110, USA
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Arias HR, Pierce SR, Germann AL, Xu SQ, Ortells MO, Sakamoto S, Manetti D, Romanelli MN, Hamachi I, Akk G. Chemical, Pharmacological, and Structural Characterization of Novel Acrylamide-Derived Modulators of the GABA A Receptor. Mol Pharmacol 2023; 104:115-131. [PMID: 37316350 PMCID: PMC10441626 DOI: 10.1124/molpharm.123.000692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/22/2023] [Accepted: 06/01/2023] [Indexed: 06/16/2023] Open
Abstract
Acrylamide-derived compounds have been previously shown to act as modulators of members of the Cys-loop transmitter-gated ion channel family, including the mammalian GABAA receptor. Here we have synthesized and functionally characterized the GABAergic effects of a series of novel compounds (termed "DM compounds") derived from the previously characterized GABAA and the nicotinic α7 receptor modulator (E)-3-furan-2-yl-N-p-tolyl-acrylamide (PAM-2). Fluorescence imaging studies indicated that the DM compounds increase apparent affinity to the transmitter by up to 80-fold in the ternary αβγ GABAA receptor. Using electrophysiology, we show that the DM compounds, and the structurally related (E)-3-furan-2-yl-N-phenylacrylamide (PAM-4), have concurrent potentiating and inhibitory effects that can be isolated and observed under appropriate recording conditions. The potentiating efficacies of the DM compounds are similar to those of neurosteroids and benzodiazepines (ΔG ∼ -1.5 kcal/mol). Molecular docking, functionally confirmed by site-directed mutagenesis experiments, indicate that receptor potentiation is mediated by interactions with the classic anesthetic binding sites located in the transmembrane domain of the intersubunit interfaces. Inhibition by the DM compounds and PAM-4 was abolished in the receptor containing the α1(V256S) mutation, suggestive of similarities in the mechanism of action with that of inhibitory neurosteroids. Functional competition and mutagenesis experiments, however, indicate that the sites mediating inhibition by the DM compounds and PAM-4 differ from those mediating the action of the inhibitory steroid pregnenolone sulfate. SIGNIFICANCE STATEMENT: We have synthesized and characterized the actions of novel acrylamide-derived compounds on the mammalian GABAA receptor. We show that the compounds have concurrent potentiating effects mediated by the classic anesthetic binding sites, and inhibitory actions that bear mechanistic resemblance to but do not share binding sites with, the inhibitory steroid pregnenolone sulfate.
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Affiliation(s)
- Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Spencer R Pierce
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Allison L Germann
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Sophia Q Xu
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Marcelo O Ortells
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Seiji Sakamoto
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Dina Manetti
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Maria Novella Romanelli
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Itaru Hamachi
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
| | - Gustav Akk
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma (H.R.A.); Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri (S.R.P., A.L.G., S.Q.X., G.A.); Facultad de Medicina, Universidad de Morón, Morón, and CONICET, Argentina (M.O.O.); Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan (S.S., I.H.); Department of Neurosciences, Psychology, Drug Research and Child Health Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, Florence, Italy (D.M., M.N.R.); The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri (G.A.)
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Pierce SR, Germann AL, Xu SQ, Menon SL, Ortells MO, Arias HR, Akk G. Mutational Analysis of Anesthetic Binding Sites and Their Effects on GABA A Receptor Activation and Modulation by Positive Allosteric Modulators of the α7 Nicotinic Receptor. Biomolecules 2023; 13:biom13040698. [PMID: 37189445 DOI: 10.3390/biom13040698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/16/2023] [Accepted: 04/18/2023] [Indexed: 05/17/2023] Open
Abstract
The positive allosteric modulators (PAMs) of the α7 nicotinic receptor N-(5-Cl-2-hydroxyphenyl)-N'-[2-Cl-5-(trifluoromethyl)phenyl]-urea (NS-1738) and (E)-3-(furan-2-yl)-N-(p-tolyl)-acrylamide (PAM-2) potentiate the α1β2γ2L GABAA receptor through interactions with the classic anesthetic binding sites located at intersubunit interfaces in the transmembrane domain of the receptor. In the present study, we employed mutational analysis to investigate in detail the involvement and contributions made by the individual intersubunit interfaces to receptor modulation by NS-1738 and PAM-2. We show that mutations to each of the anesthetic-binding intersubunit interfaces (β+/α-, α+/β-, and γ+/β-), as well as the orphan α+/γ- interface, modify receptor potentiation by NS-1738 and PAM-2. Furthermore, mutations to any single interface can fully abolish potentiation by the α7-PAMs. The findings are discussed in the context of energetic additivity and interactions between the individual binding sites.
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Affiliation(s)
- Spencer R Pierce
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Allison L Germann
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sophia Q Xu
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Saumith L Menon
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marcelo O Ortells
- Facultad de Medicina, Universidad de Morón, CONICET, Morón 1708, Argentina
| | - Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, OK 74464, USA
| | - Gustav Akk
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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Schmiedhofer P, Vogel FD, Koniuszewski F, Ernst M. Cys-loop receptors on cannabinoids: All high? Front Physiol 2022; 13:1044575. [PMID: 36439263 PMCID: PMC9682269 DOI: 10.3389/fphys.2022.1044575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 10/24/2022] [Indexed: 11/10/2022] Open
Abstract
Endocannabinoids (eCBS) are endogenously derived lipid signaling molecules that serve as tissue hormones and interact with multiple targets, mostly within the endocannabinoid system (ECS). The ECS is a highly conserved regulatory system involved in homeostatic regulation, organ formation, and immunomodulation of chordates. The term “cannabinoid” evolved from the distinctive class of plant compounds found in Cannabis sativa, an ancient herb, due to their action on CB1 and CB2 receptors. CB1/2 receptors are the primary targets for eCBs, but their effects are not limited to the ECS. Due to the high interest and extensive research on the ECS, knowledge on its constituents and physiological role is substantial and still growing. Crosstalk and multiple targeting of molecules are common features of endogenous and plant compounds. Cannabimimetic molecules can be divided according to their origin, natural or synthetic, including phytocannabinoids (pCB’s) or synthetic cannabinoids (sCB’s). The endocannabinoid system (ECS) consists of receptors, transporters, enzymes, and signaling molecules. In this review, we focus on the effects of cannabinoids on Cys-loop receptors. Cys-loop receptors belong to the class of membrane-bound pentameric ligand gated ion channels, each family comprising multiple subunits. Mammalians possess GABA type A receptors (GABAAR), glycine receptors (GlyR), serotonin receptors type 3 (5-HT3R), and nicotinic acetylcholine receptors (nAChR). Several studies have shown different modulatory effects of CBs on multiple members of the Cys-loop receptor family. We highlight the existing knowledge, especially on subunits and protein domains with conserved binding sites for CBs and their possible pharmacological and physiological role in epilepsy and in chronic pain. We further discuss the potential for cannabinoids as first line treatments in epilepsy, chronic pain and other neuropsychiatric conditions, indicated by their polypharmacology and therapeutic profile.
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Affiliation(s)
- Philip Schmiedhofer
- SBR Development Holding, Vienna, Austria
- *Correspondence: Philip Schmiedhofer, ; Margot Ernst,
| | - Florian Daniel Vogel
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Filip Koniuszewski
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University Vienna, Vienna, Austria
| | - Margot Ernst
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University Vienna, Vienna, Austria
- *Correspondence: Philip Schmiedhofer, ; Margot Ernst,
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