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Gallino SL, Agüero L, Boffi JC, Schottlender G, Buonfiglio P, Dalamon V, Marcovich I, Carpaneto A, Craig PO, Plazas PV, Elgoyhen AB. Key role of the TM2-TM3 loop in calcium potentiation of the α9α10 nicotinic acetylcholine receptor. Cell Mol Life Sci 2024; 81:337. [PMID: 39120784 PMCID: PMC11335262 DOI: 10.1007/s00018-024-05381-2] [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: 01/19/2024] [Revised: 07/09/2024] [Accepted: 07/23/2024] [Indexed: 08/10/2024]
Abstract
The α9α10 nicotinic cholinergic receptor (nAChR) is a ligand-gated pentameric cation-permeable ion channel that mediates synaptic transmission between descending efferent neurons and mechanosensory inner ear hair cells. When expressed in heterologous systems, α9 and α10 subunits can assemble into functional homomeric α9 and heteromeric α9α10 receptors. One of the differential properties between these nAChRs is the modulation of their ACh-evoked responses by extracellular calcium (Ca2+). While α9 nAChRs responses are blocked by Ca2+, ACh-evoked currents through α9α10 nAChRs are potentiated by Ca2+ in the micromolar range and blocked at millimolar concentrations. Using chimeric and mutant subunits, together with electrophysiological recordings under two-electrode voltage-clamp, we show that the TM2-TM3 loop of the rat α10 subunit contains key structural determinants responsible for the potentiation of the α9α10 nAChR by extracellular Ca2+. Moreover, molecular dynamics simulations reveal that the TM2-TM3 loop of α10 does not contribute to the Ca2+ potentiation phenotype through the formation of novel Ca2+ binding sites not present in the α9 receptor. These results suggest that the TM2-TM3 loop of α10 might act as a control element that facilitates the intramolecular rearrangements that follow ACh-evoked α9α10 nAChRs gating in response to local and transient changes of extracellular Ca2+ concentration. This finding might pave the way for the future rational design of drugs that target α9α10 nAChRs as otoprotectants.
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Affiliation(s)
- Sofia L Gallino
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Lucía Agüero
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Juan C Boffi
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, Monterotondo, Italy
| | - Gustavo Schottlender
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Paula Buonfiglio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Viviana Dalamon
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Irina Marcovich
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Regeneron Pharmaceuticals, Inc. Tarrytown, 10591, NY, USA
| | - Agustín Carpaneto
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Patricio O Craig
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Instituto de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (IQUIBICEN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Paola V Plazas
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
| | - Ana B Elgoyhen
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular ''Dr. Héctor N. Torres'' (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
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2
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Liu X, Wang W. Gating mechanism of the human α1β GlyR by glycine. Structure 2024:S0969-2126(24)00275-2. [PMID: 39146932 DOI: 10.1016/j.str.2024.07.012] [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: 02/02/2024] [Revised: 06/20/2024] [Accepted: 07/19/2024] [Indexed: 08/17/2024]
Abstract
Glycine receptors (GlyRs) are members of the Cys-loop receptors that constitute a major portion of mammalian neurotransmitter receptors. Recent resolution of heteromeric GlyR structures in multiple functional states raised fundamental questions regarding the gating mechanism of GlyR, and generally the Cys-loop family receptors. Here, we characterized in detail equilibrium properties as well as the transition kinetics between functional states. We show that, while all allosteric sites bind cooperatively to glycine, occupation of 2 sites at the α-α interfaces is sufficient for activation and necessary for high-efficacy gating. Differential glycine concentration dependence of desensitization rate, extent, and its recovery suggests separate but concerted roles of ligand-binding and ionophore reorganization. Based on these observations and available structural information, we developed a quantitative gating model that accurately predicts both equilibrium and kinetical properties throughout the glycine gating cycle. This model likely applies generally to the Cys-loop receptors and informs on pharmaceutical endeavors.
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Affiliation(s)
- Xiaofen Liu
- Departments of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Weiwei Wang
- Departments of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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3
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Read RJ, Pettersen EF, McCoy AJ, Croll TI, Terwilliger TC, Poon BK, Meng EC, Liebschner D, Adams PD. Likelihood-based interactive local docking into cryo-EM maps in ChimeraX. Acta Crystallogr D Struct Biol 2024; 80:588-598. [PMID: 39058381 DOI: 10.1107/s2059798324006776] [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: 05/15/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024] Open
Abstract
The interpretation of cryo-EM maps often includes the docking of known or predicted structures of the components, which is particularly useful when the map resolution is worse than 4 Å. Although it can be effective to search the entire map to find the best placement of a component, the process can be slow when the maps are large. However, frequently there is a well-founded hypothesis about where particular components are located. In such cases, a local search using a map subvolume will be much faster because the search volume is smaller, and more sensitive because optimizing the search volume for the rotation-search step enhances the signal to noise. A Fourier-space likelihood-based local search approach, based on the previously published em_placement software, has been implemented in the new emplace_local program. Tests confirm that the local search approach enhances the speed and sensitivity of the computations. An interactive graphical interface in the ChimeraX molecular-graphics program provides a convenient way to set up and evaluate docking calculations, particularly in defining the part of the map into which the components should be placed.
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Affiliation(s)
- Randy J Read
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Eric F Pettersen
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Airlie J McCoy
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 0XY, United Kingdom
| | | | | | - Billy K Poon
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Elaine C Meng
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, USA
| | - Dorothee Liebschner
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Paul D Adams
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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4
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Li H, Teng J, Hibbs RE. Structural switch in acetylcholine receptors in developing muscle. Nature 2024; 632:1174-1180. [PMID: 39085615 DOI: 10.1038/s41586-024-07774-6] [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: 03/08/2024] [Accepted: 07/02/2024] [Indexed: 08/02/2024]
Abstract
During development, motor neurons originating in the brainstem and spinal cord form elaborate synapses with skeletal muscle fibres1. These neurons release acetylcholine (ACh), which binds to nicotinic ACh receptors (AChRs) on the muscle, initiating contraction. Two types of AChR are present in developing muscle cells, and their differential expression serves as a hallmark of neuromuscular synapse maturation2-4. The structural principles underlying the switch from fetal to adult muscle receptors are unknown. Here, we present high-resolution structures of both fetal and adult muscle nicotinic AChRs, isolated from bovine skeletal muscle in developmental transition. These structures, obtained in the absence and presence of ACh, provide a structural context for understanding how fetal versus adult receptor isoforms are tuned for synapse development versus the all-or-none signalling required for high-fidelity skeletal muscle contraction. We find that ACh affinity differences are driven by binding site access, channel conductance is tuned by widespread surface electrostatics and open duration changes result from intrasubunit interactions and structural flexibility. The structures further reveal pathogenic mechanisms underlying congenital myasthenic syndromes.
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Affiliation(s)
- Huanhuan Li
- Department of Neurobiology, University of California San Diego, La Jolla, CA, USA
| | - Jinfeng Teng
- Department of Neurobiology, University of California San Diego, La Jolla, CA, USA
| | - Ryan E Hibbs
- Department of Neurobiology, University of California San Diego, La Jolla, CA, USA.
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA.
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5
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Do HQ, Pirayesh E, Ferreira G, Pandhare A, Gallardo ZR, Jansen M. A bupropion modulatory site in the Gloeobacter violaceus ligand-gated ion channel. Biophys J 2024; 123:2185-2198. [PMID: 38678367 PMCID: PMC11309978 DOI: 10.1016/j.bpj.2024.04.027] [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: 10/09/2023] [Revised: 01/27/2024] [Accepted: 04/25/2024] [Indexed: 04/29/2024] Open
Abstract
Bupropion is an atypical antidepressant and smoking cessation drug that causes adverse effects such as insomnia, irritability, and anxiety. Bupropion inhibits dopamine and norepinephrine reuptake transporters and eukaryotic cation-conducting pentameric ligand-gated ion channels, such as nicotinic acetylcholine and serotonin type 3A receptors, at clinically relevant concentrations. Here, we demonstrate that bupropion also inhibits a prokaryotic homolog of pentameric ligand-gated ion channels, the Gloeobacter violaceus ligand-gated ion channel (GLIC). Using the GLIC as a model, we used molecular docking to predict binding sites for bupropion. Bupropion was found to bind to several sites within the transmembrane domain, with the predominant site being localized to the interface between transmembrane segments M1 and M3 of two adjacent subunits. Residues W213, T214, and W217 in the first transmembrane segment, M1, and F267 and I271 in the third transmembrane segment, M3, most frequently reside within a 4 Å distance from bupropion. We then used single amino acid substitutions at these positions and two-electrode voltage-clamp recordings to determine their impact on bupropion inhibitory effects. The substitution T214F alters bupropion potency by shifting the half-maximal inhibitory concentration to a 13-fold higher value compared to wild-type GLIC. Residue T214 is found within a previously identified binding pocket for neurosteroids and lipids in the GLIC. This intersubunit binding pocket is structurally conserved and almost identical to a binding pocket described for neurosteroids in γ-aminobutyric acid type A receptors. Our data thus suggest that the T214 that lines a previously identified lipophilic binding pocket in GLIC and γ-aminobutyric acid type A receptors is also a modulatory site for bupropion interaction with the GLIC.
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Affiliation(s)
- Hoa Quynh Do
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Elham Pirayesh
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Garren Ferreira
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Akash Pandhare
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Zackary Ryan Gallardo
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Michaela Jansen
- Cell Physiology and Molecular Biophysics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas.
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6
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Kaiser J, Gertzen CGW, Bernauer T, Nitsche V, Höfner G, Niessen KV, Seeger T, Paintner FF, Wanner KT, Steinritz D, Worek F, Gohlke H. Identification of ligands binding to MB327-PAM-1, a binding pocket relevant for resensitization of nAChRs. Toxicol Lett 2024; 398:91-104. [PMID: 38768836 DOI: 10.1016/j.toxlet.2024.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 04/13/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Desensitization of nicotinic acetylcholine receptors (nAChRs) can be induced by overstimulation with acetylcholine (ACh) caused by an insufficient degradation of ACh after poisoning with organophosphorus compounds (OPCs). Currently, there is no generally applicable treatment for OPC poisoning that directly targets the desensitized nAChR. The bispyridinium compound MB327, an allosteric modulator of nAChR, has been shown to act as a resensitizer of nAChRs, indicating that drugs binding directly to nAChRs can have beneficial effects after OPC poisoning. However, MB327 also acts as an inhibitor of nAChRs at higher concentrations and can thus not be used for OPC poisoning treatment. Consequently, novel, more potent resensitizers are required. To successfully design novel ligands, the knowledge of the binding site is of utmost importance. Recently, we performed in silico studies to identify a new potential binding site of MB327, MB327-PAM-1, for which a more affine ligand, UNC0646, has been described. In this work, we performed ligand-based screening approaches to identify novel analogs of UNC0646 to help further understand the structure-affinity relationship of this compound class. Furthermore, we used structure-based screenings and identified compounds representing four new chemotypes binding to MB327-PAM-1. One of these compounds, cycloguanil, is the active metabolite of the antimalaria drug proguanil and shows a higher affinity towards MB327-PAM-1 than MB327. Furthermore, cycloguanil can reestablish the muscle force in soman-inhibited rat muscles. These results can act as a starting point to develop more potent resensitizers of nAChR and to close the gap in the treatment after OPC poisoning.
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Affiliation(s)
- Jesko Kaiser
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christoph G W Gertzen
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tamara Bernauer
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Valentin Nitsche
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Georg Höfner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Karin V Niessen
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Thomas Seeger
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Franz F Paintner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Klaus T Wanner
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Dirk Steinritz
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; Institute of Bio- and Geosciences (IBG-4: Bioinformatics), Forschungszentrum Jülich, Jülich, Germany.
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7
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Nemecz D, Nowak WA, Nemecz Á. VHH Nanobody Versatility against Pentameric Ligand-Gated Ion Channels. J Med Chem 2024; 67:8502-8518. [PMID: 38829690 PMCID: PMC11181324 DOI: 10.1021/acs.jmedchem.4c00231] [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: 01/26/2024] [Revised: 04/17/2024] [Accepted: 05/20/2024] [Indexed: 06/05/2024]
Abstract
Pentameric ligand-gated ion channels provide rapid chemical-electrical signal transmission between cells in the central and peripheral nervous system. Their dysfunction is associated with many nervous system disorders. They are composed of five identical (homomeric receptors) or homologous (heteromeric receptors) subunits. VHH nanobodies, or single-chain antibodies, are the variable domain, VHH, of antibodies that are composed of the heavy chain only from camelids. Their unique structure results in many specific biochemical and biophysical properties that make them an excellent alternative to conventional antibodies. This Perspective explores the published VHH nanobodies which have been isolated against pentameric ligand-gated ion channel subfamilies. It outlines the genetic and chemical modifications available to alter nanobody function. An assessment of the available functional and structural data indicate that it is feasible to create therapeutic agents and impart, through their modification, a given desired modulatory effect of its target receptor for current stoichiometric-specific VHH nanobodies.
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Affiliation(s)
- Dorota Nemecz
- Biochemistry
Department, Nicolaus Copernicus University
in Torun, 87-100 Torun, Poland
| | - Weronika A. Nowak
- Biochemistry
Department, Nicolaus Copernicus University
in Torun, 87-100 Torun, Poland
| | - Ákos Nemecz
- Biochemistry
Department, Nicolaus Copernicus University
in Torun, 87-100 Torun, Poland
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8
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Santis GD, Okura Y, Hirata K, Ishiuchi SI, Fujii M, Xantheas SS. Affinity of Nicotinoids to a Model Nicotinic Acetylcholine Receptor (nAChR) Binding Pocket in the Human Brain. J Phys Chem B 2024; 128:4577-4589. [PMID: 38696590 DOI: 10.1021/acs.jpcb.3c07919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
The binding affinity of nicotinoids to the binding residues of the α4β2 variant of the nicotinic acetylcholine receptor (nAChR) was identified as a strong predictor of the nicotinoid's addictive character. Using ab initio calculations for model binding pockets of increasing size composed of 3, 6, and 14 amino acids (3AA, 6AA, and 14AA) that are derived from the crystal structure, the differences in binding affinity of 6 nicotinoids, namely, nicotine (NIC), nornicotine (NOR), anabasine (ANB), anatabine (ANT), myosmine (MYO), and cotinine (COT) were correlated to their previously reported doses required for increases in intracranial self-stimulation (ICSS) thresholds, a metric for their addictive function. By employing the many-body decomposition, the differences in the binding affinities of the various nicotinoids could be attributed mainly to the proton exchange energy between the pyridine and non-pyridine rings of the nicotinoids and the interactions between them and a handful of proximal amino acids, namely Trp156, Trpβ57, Tyr100, and Tyr204. Interactions between the guest nicotinoid and the amino acids of the binding pocket were found to be mainly classical in nature, except for those between the nicotinoid and Trp156. The larger pockets were found to model binding structures more accurately and predicted the addictive character of all nicotinoids, while smaller models, which are more computationally feasible, would only predict the addictive character of nicotinoids that are similar to nicotine. The present study identifies the binding affinity of the guest nicotinoid to the host binding pocket as a strong descriptor of the nicotinoid's addiction potential, and as such it can be employed as a fast-screening technique for the potential addiction of nicotine analogs.
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Affiliation(s)
- Garrett D Santis
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Yuika Okura
- Department of Chemistry, School of Science, Tokyo Intitute of Technology; 2-12-1 4259 Ookayama, Meguro-ku, Tokyo 152855, Japan
| | - Keisuke Hirata
- Department of Chemistry, School of Science, Tokyo Intitute of Technology; 2-12-1 4259 Ookayama, Meguro-ku, Tokyo 152855, Japan
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Shun-Ichi Ishiuchi
- Department of Chemistry, School of Science, Tokyo Intitute of Technology; 2-12-1 4259 Ookayama, Meguro-ku, Tokyo 152855, Japan
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Masaaki Fujii
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503, Japan
- Research and Development Initiative, Chuo University, Tokyo 112-8551, Japan
| | - Sotiris S Xantheas
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovation Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
- Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, MS K1-83, P.O. Box 999, Richland, Washington 99352, United States
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9
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Sampaio Moura N, Schledwitz A, Alizadeh M, Kodan A, Njei LP, Raufman JP. Cholinergic Mechanisms in Gastrointestinal Neoplasia. Int J Mol Sci 2024; 25:5316. [PMID: 38791353 PMCID: PMC11120676 DOI: 10.3390/ijms25105316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/09/2024] [Accepted: 05/11/2024] [Indexed: 05/26/2024] Open
Abstract
Acetylcholine-activated receptors are divided broadly into two major structurally distinct classes: ligand-gated ion channel nicotinic and G-protein-coupled muscarinic receptors. Each class encompasses several structurally related receptor subtypes with distinct patterns of tissue expression and post-receptor signal transduction mechanisms. The activation of both nicotinic and muscarinic cholinergic receptors has been associated with the induction and progression of gastrointestinal neoplasia. Herein, after briefly reviewing the classification of acetylcholine-activated receptors and the role that nicotinic and muscarinic cholinergic signaling plays in normal digestive function, we consider the mechanics of acetylcholine synthesis and release by neuronal and non-neuronal cells in the gastrointestinal microenvironment, and current methodology and challenges in measuring serum and tissue acetylcholine levels accurately. Then, we critically evaluate the evidence that constitutive and ligand-induced activation of acetylcholine-activated receptors plays a role in promoting gastrointestinal neoplasia. We focus primarily on adenocarcinomas of the stomach, pancreas, and colon, because these cancers are particularly common worldwide and, when diagnosed at an advanced stage, are associated with very high rates of morbidity and mortality. Throughout this comprehensive review, we concentrate on identifying novel ways to leverage these observations for prognostic and therapeutic purposes.
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Affiliation(s)
- Natalia Sampaio Moura
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.S.M.); (A.S.); (A.K.)
| | - Alyssa Schledwitz
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.S.M.); (A.S.); (A.K.)
| | - Madeline Alizadeh
- The Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Asha Kodan
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.S.M.); (A.S.); (A.K.)
| | - Lea-Pearl Njei
- Department of Biological Science, University of Maryland, Baltimore County, Baltimore, MD 21250, USA;
| | - Jean-Pierre Raufman
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.S.M.); (A.S.); (A.K.)
- Veterans Affairs Maryland Healthcare System, Baltimore, MD 21201, USA
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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10
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Ananchenko A, Gao RY, Dehez F, Baenziger JE. State-dependent binding of cholesterol and an anionic lipid to the muscle-type Torpedo nicotinic acetylcholine receptor. Commun Biol 2024; 7:437. [PMID: 38600247 PMCID: PMC11006840 DOI: 10.1038/s42003-024-06106-8] [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: 08/28/2023] [Accepted: 03/25/2024] [Indexed: 04/12/2024] Open
Abstract
The ability of the Torpedo nicotinic acetylcholine receptor (nAChR) to undergo agonist-induced conformational transitions requires the presence of cholesterol and/or anionic lipids. Here we use recently solved structures along with multiscale molecular dynamics simulations to examine lipid binding to the nAChR in bilayers that have defined effects on nAChR function. We examine how phosphatidic acid and cholesterol, lipids that support conformational transitions, individually compete for binding with phosphatidylcholine, a lipid that does not. We also examine how the two lipids work synergistically to stabilize an agonist-responsive nAChR. We identify rapidly exchanging lipid binding sites, including both phospholipid sites with a high affinity for phosphatidic acid and promiscuous cholesterol binding sites in the grooves between adjacent transmembrane α-helices. A high affinity cholesterol site is confirmed in the inner leaflet framed by a key tryptophan residue on the MX α-helix. Our data provide insight into the dynamic nature of lipid-nAChR interactions and set the stage for a detailed understanding of the mechanisms by which lipids facilitate nAChR function at the neuromuscular junction.
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Affiliation(s)
- Anna Ananchenko
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Rui Yan Gao
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - François Dehez
- CNRS, LPCT, Université de Lorraine, F-54000 Nancy, France.
| | - John E Baenziger
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada.
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11
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Bharambe N, Li Z, Seiferth D, Balakrishna AM, Biggin PC, Basak S. Cryo-EM structures of prokaryotic ligand-gated ion channel GLIC provide insights into gating in a lipid environment. Nat Commun 2024; 15:2967. [PMID: 38580666 PMCID: PMC10997623 DOI: 10.1038/s41467-024-47370-w] [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: 02/22/2023] [Accepted: 03/28/2024] [Indexed: 04/07/2024] Open
Abstract
GLIC, a proton-activated prokaryotic ligand-gated ion channel, served as a model system for understanding the eukaryotic counterparts due to their structural and functional similarities. Despite extensive studies conducted on GLIC, the molecular mechanism of channel gating in the lipid environment requires further investigation. Here, we present the cryo-EM structures of nanodisc-reconstituted GLIC at neutral and acidic pH in the resolution range of 2.6 - 3.4 Å. In our apo state at pH 7.5, the extracellular domain (ECD) displays conformational variations compared to the existing apo structures. At pH 4.0, three distinct conformational states (C1, C2 and O states) are identified. The protonated structures exhibit a compacted and counter-clockwise rotated ECD compared with our apo state. A gradual widening of the pore in the TMD is observed upon reducing the pH, with the widest pore in O state, accompanied by several layers of water pentagons. The pore radius and molecular dynamics (MD) simulations suggest that the O state represents an open conductive state. We also observe state-dependent interactions between several lipids and proteins that may be involved in the regulation of channel gating. Our results provide comprehensive insights into the importance of lipids impact on gating.
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Affiliation(s)
- Nikhil Bharambe
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Zhuowen Li
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - David Seiferth
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Philip C Biggin
- Structural Bioinformatics and Computational Biochemistry, Department of Biochemistry, University of Oxford, Oxford, UK
| | - Sandip Basak
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, 639798, Singapore.
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12
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Son L, Kost V, Maiorov V, Sukhov D, Arkhangelskaya P, Ivanov I, Kudryavtsev D, Siniavin A, Utkin Y, Kasheverov I. Efficient Expression in Leishmania tarentolae (LEXSY) of the Receptor-Binding Domain of the SARS-CoV-2 S-Protein and the Acetylcholine-Binding Protein from Lymnaea stagnalis. Molecules 2024; 29:943. [PMID: 38474455 DOI: 10.3390/molecules29050943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/31/2024] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
Leishmania tarentolae (LEXSY) system is an inexpensive and effective expression approach for various research and medical purposes. The stated advantages of this system are the possibility of obtaining the soluble product in the cytoplasm, a high probability of correct protein folding with a full range of post-translational modifications (including uniform glycosylation), and the possibility of expressing multi-subunit proteins. In this paper, a LEXSY expression system has been employed for obtaining the receptor binding domain (RBD) of the spike-protein of the SARS-CoV-2 virus and the homopentameric acetylcholine-binding protein (AChBP) from Lymnaea stagnalis. RBD is actively used to obtain antibodies against the virus and in various scientific studies on the molecular mechanisms of the interaction of the virus with host cell targets. AChBP represents an excellent structural model of the ligand-binding extracellular domain of all subtypes of nicotinic acetylcholine receptors (nAChRs). Both products were obtained in a soluble glycosylated form, and their structural and functional characteristics were compared with those previously described.
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Affiliation(s)
- Lina Son
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Vladimir Kost
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Valery Maiorov
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Dmitry Sukhov
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Polina Arkhangelskaya
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Igor Ivanov
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Denis Kudryavtsev
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Andrei Siniavin
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Ivanovsky Institute of Virology, N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, 123098 Moscow, Russia
| | - Yuri Utkin
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Igor Kasheverov
- Department of Molecular Bases of Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
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13
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Yin C, O’Reilly AO, Liu SN, Du TH, Gong PP, Zhang CJ, Wei XG, Yang J, Huang MJ, Fu BL, Liang JJ, Xue H, Hu JY, Ji Y, He C, Du H, Wang C, Zhang R, Tan QM, Lu HT, Xie W, Chu D, Zhou XG, Nauen R, Gui LY, Bass C, Yang X, Zhang YJ. Dual mutations in the whitefly nicotinic acetylcholine receptor β1 subunit confer target-site resistance to multiple neonicotinoid insecticides. PLoS Genet 2024; 20:e1011163. [PMID: 38377137 PMCID: PMC10906874 DOI: 10.1371/journal.pgen.1011163] [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: 08/25/2023] [Revised: 03/01/2024] [Accepted: 01/30/2024] [Indexed: 02/22/2024] Open
Abstract
Neonicotinoid insecticides, which target insect nicotinic acetylcholine receptors (nAChRs), have been widely and intensively used to control the whitefly, Bemisia tabaci, a highly damaging, globally distributed, crop pest. This has inevitably led to the emergence of populations with resistance to neonicotinoids. However, to date, there have been no reports of target-site resistance involving mutation of B. tabaci nAChR genes. Here we characterize the nAChR subunit gene family of B. tabaci and identify dual mutations (A58T&R79E) in one of these genes (BTβ1) that confer resistance to multiple neonicotinoids. Transgenic D. melanogaster, where the native nAChR Dβ1 was replaced with BTβ1A58T&R79E, were significantly more resistant to neonicotinoids than flies where Dβ1 were replaced with the wildtype BTβ1 sequence, demonstrating the causal role of the mutations in resistance. The two mutations identified in this study replace two amino acids that are highly conserved in >200 insect species. Three-dimensional modelling suggests a molecular mechanism for this resistance, whereby A58T forms a hydrogen bond with the R79E side chain, which positions its negatively-charged carboxylate group to electrostatically repulse a neonicotinoid at the orthosteric site. Together these findings describe the first case of target-site resistance to neonicotinoids in B. tabaci and provide insight into the molecular determinants of neonicotinoid binding and selectivity.
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Affiliation(s)
- Cheng Yin
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
- Hubei Engineering Technology Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, Hubei, P. R. China
| | - Andrias O. O’Reilly
- School of Biological & Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Shao-Nan Liu
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Tian-Hua Du
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Pei-Pan Gong
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Cheng-Jia Zhang
- Hunan Provincial Key laboratory of Pesticide Biology and Precise Use Techology, Hunan Agricultural Biotechnology Research Institute, Changsha, P. R. China
| | - Xue-Gao Wei
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Jing Yang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Ming-Jiao Huang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Bu-Li Fu
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Jin-Jin Liang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Hu Xue
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Jin-Yu Hu
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Yao Ji
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Chao He
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - He Du
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Chao Wang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Rong Zhang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Qi-Mei Tan
- Hunan Provincial Key laboratory of Pesticide Biology and Precise Use Techology, Hunan Agricultural Biotechnology Research Institute, Changsha, P. R. China
| | - Han-Tang Lu
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Wen Xie
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - Dong Chu
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, School of Agriculture and Plant Protection, Qingdao Agricultural University, Qingdao, Shandong Province, China
| | - Xu-Guo Zhou
- Department of Entomology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Ralf Nauen
- Bayer AG, Crop Science Division, R&D, Monheim, Germany
| | - Lian-You Gui
- Hubei Engineering Technology Center for Pest Forewarning and Management, College of Agriculture, Yangtze University, Jingzhou, Hubei, P. R. China
| | - Chris Bass
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
| | - Xin Yang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
| | - You-Jun Zhang
- State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, P. R. China
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14
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Gotti C, Clementi F, Zoli M. Auxiliary protein and chaperone regulation of neuronal nicotinic receptor subtype expression and function. Pharmacol Res 2024; 200:107067. [PMID: 38218358 DOI: 10.1016/j.phrs.2024.107067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 01/15/2024]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are a family of pentameric, ligand-gated ion channels that are located on the surface of neurons and non-neuronal cells and have multiple physiological and pathophysiological functions. In order to reach the cell surface, many nAChR subtypes require the help of chaperone and/or auxiliary/accessory proteins for their assembly, trafficking, pharmacological modulation, and normal functioning in vivo. The use of powerful genome-wide cDNA screening has led to the identification and characterisation of the molecules and mechanisms that participate in the assembly and trafficking of receptor subtypes, including chaperone and auxiliary or accessory proteins. The aim of this review is to describe the latest findings concerning nAChR chaperones and auxiliary proteins and pharmacological chaperones, and how some of them control receptor biogenesis or regulate channel activation and pharmacology. Some auxiliary proteins are subtype selective, some regulate various subtypes, and some not only modulate nAChRs but also target other receptors and signalling pathways. We also discuss how changes in auxiliary proteins may be involved in nAChR dysfunctions.
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Affiliation(s)
- Cecilia Gotti
- CNR, Institute of Neuroscience, Milan, Italy; NeuroMi Milan Center for Neuroscience, University of Milano-Bicocca, Italy.
| | - Francesco Clementi
- CNR, Institute of Neuroscience, Milan, Italy; Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Michele Zoli
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology (CfNN), University of Modena and Reggio Emilia, Modena, Italy
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15
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Bergh C, Rovšnik U, Howard R, Lindahl E. Discovery of lipid binding sites in a ligand-gated ion channel by integrating simulations and cryo-EM. eLife 2024; 12:RP86016. [PMID: 38289224 PMCID: PMC10945520 DOI: 10.7554/elife.86016] [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] [Indexed: 02/01/2024] Open
Abstract
Ligand-gated ion channels transduce electrochemical signals in neurons and other excitable cells. Aside from canonical ligands, phospholipids are thought to bind specifically to the transmembrane domain of several ion channels. However, structural details of such lipid contacts remain elusive, partly due to limited resolution of these regions in experimental structures. Here, we discovered multiple lipid interactions in the channel GLIC by integrating cryo-electron microscopy and large-scale molecular simulations. We identified 25 bound lipids in the GLIC closed state, a conformation where none, to our knowledge, were previously known. Three lipids were associated with each subunit in the inner leaflet, including a buried interaction disrupted in mutant simulations. In the outer leaflet, two intrasubunit sites were evident in both closed and open states, while a putative intersubunit site was preferred in open-state simulations. This work offers molecular details of GLIC-lipid contacts particularly in the ill-characterized closed state, testable hypotheses for state-dependent binding, and a multidisciplinary strategy for modeling protein-lipid interactions.
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Affiliation(s)
- Cathrine Bergh
- Science for Life Laboratory & Swedish e-Science Research Center, Department of Applied Physics, KTH Royal Institute of TechnologyStockholmSweden
| | - Urška Rovšnik
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Rebecca Howard
- Science for Life Laboratory & Swedish e-Science Research Center, Department of Applied Physics, KTH Royal Institute of TechnologyStockholmSweden
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
| | - Erik Lindahl
- Science for Life Laboratory & Swedish e-Science Research Center, Department of Applied Physics, KTH Royal Institute of TechnologyStockholmSweden
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm UniversityStockholmSweden
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16
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Rusali LE, Lopez-Hernandez AM, Kremiller KM, Kulkarni GC, Gour A, Straub CJ, Argade MD, Peters CJ, Sharma A, Toll L, Cippitelli A, Riley AP. Synthesis of α3β4 Nicotinic Acetylcholine Receptor Modulators Derived from Aristoquinoline That Reduce Reinstatement of Cocaine-Seeking Behavior. J Med Chem 2024; 67:529-542. [PMID: 38151460 PMCID: PMC10872344 DOI: 10.1021/acs.jmedchem.3c01758] [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] [Indexed: 12/29/2023]
Abstract
Growing evidence suggests that inhibition of the α3β4 nicotinic acetylcholine receptor (nAChR) represents a promising therapeutic strategy to treat cocaine use disorder. Recently, aristoquinoline (1), an alkaloid from Aristotelia chilensis, was identified as an α3β4-selective nAChR inhibitor. Here, we prepared 22 derivatives of 1 and evaluated their ability to inhibit the α3β4 nAChR. These studies revealed structure-activity trends and several compounds with increased potency compared to 1 with few off-target liabilities. Additional mechanistic studies indicated that these compounds inhibit the α3β4 nAChR noncompetitively, but do not act as channel blockers, suggesting they are negative allosteric modulators. Finally, using a cocaine-primed reinstatement paradigm, we demonstrated that 1 significantly attenuates drug-seeking behavior in an animal model of cocaine relapse. The results from these studies further support a role for the α3β4 nAChR in the addictive properties of cocaine and highlight the possible utility of aristoquinoline derivatives in treating cocaine use disorder.
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Affiliation(s)
- Lisa E. Rusali
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Ana M. Lopez-Hernandez
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Kyle M. Kremiller
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Gauri C. Kulkarni
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Abhishek Gour
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL 32610, United States
| | - Carolyn J. Straub
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Malaika D. Argade
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Christian J. Peters
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612, United States
| | - Abhisheak Sharma
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL 32610, United States
| | - Lawrence Toll
- Biomedical Science Department, Charles E. Schmidt College of Medicine, Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL 33458, United States
| | - Andrea Cippitelli
- Biomedical Science Department, Charles E. Schmidt College of Medicine, Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL 33458, United States
| | - Andrew P. Riley
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL 60612, United States
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17
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Barrantes FJ. Modulation of a rapid neurotransmitter receptor-ion channel by membrane lipids. Front Cell Dev Biol 2024; 11:1328875. [PMID: 38274273 PMCID: PMC10808158 DOI: 10.3389/fcell.2023.1328875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024] Open
Abstract
Membrane lipids modulate the proteins embedded in the bilayer matrix by two non-exclusive mechanisms: direct or indirect. The latter comprise those effects mediated by the physicochemical state of the membrane bilayer, whereas direct modulation entails the more specific regulatory effects transduced via recognition sites on the target membrane protein. The nicotinic acetylcholine receptor (nAChR), the paradigm member of the pentameric ligand-gated ion channel (pLGIC) superfamily of rapid neurotransmitter receptors, is modulated by both mechanisms. Reciprocally, the nAChR protein exerts influence on its surrounding interstitial lipids. Folding, conformational equilibria, ligand binding, ion permeation, topography, and diffusion of the nAChR are modulated by membrane lipids. The knowledge gained from biophysical studies of this prototypic membrane protein can be applied to other neurotransmitter receptors and most other integral membrane proteins.
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Affiliation(s)
- Francisco J. Barrantes
- Biomedical Research Institute (BIOMED), Catholic University of Argentina (UCA)–National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
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18
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Nagori K, Pradhan M, Sharma M, Ajazuddin, Badwaik HR, Nakhate KT. Current Progress on Central Cholinergic Receptors as Therapeutic Targets for Alzheimer's Disease. Curr Alzheimer Res 2024; 21:50-68. [PMID: 38529600 DOI: 10.2174/0115672050306008240321034006] [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: 01/23/2024] [Revised: 02/22/2024] [Accepted: 02/26/2024] [Indexed: 03/27/2024]
Abstract
Acetylcholine (ACh) is ubiquitously present in the nervous system and has been involved in the regulation of various brain functions. By modulating synaptic transmission and promoting synaptic plasticity, particularly in the hippocampus and cortex, ACh plays a pivotal role in the regulation of learning and memory. These procognitive actions of ACh are mediated by the neuronal muscarinic and nicotinic cholinergic receptors. The impairment of cholinergic transmission leads to cognitive decline associated with aging and dementia. Therefore, the cholinergic system has been of prime focus when concerned with Alzheimer's disease (AD), the most common cause of dementia. In AD, the extensive destruction of cholinergic neurons occurs by amyloid-β plaques and tau protein-rich neurofibrillary tangles. Amyloid-β also blocks cholinergic receptors and obstructs neuronal signaling. This makes the central cholinergic system an important target for the development of drugs for AD. In fact, centrally acting cholinesterase inhibitors like donepezil and rivastigmine are approved for the treatment of AD, although the outcome is not satisfactory. Therefore, identification of specific subtypes of cholinergic receptors involved in the pathogenesis of AD is essential to develop future drugs. Also, the identification of endogenous rescue mechanisms to the cholinergic system can pave the way for new drug development. In this article, we discussed the neuroanatomy of the central cholinergic system. Further, various subtypes of muscarinic and nicotinic receptors involved in the cognition and pathophysiology of AD are described in detail. The article also reviewed primary neurotransmitters that regulate cognitive processes by modulating basal forebrain cholinergic projection neurons.
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Affiliation(s)
- Kushagra Nagori
- Department of Pharmaceutical Chemistry, Rungta College of Pharmaceutical Sciences and Research, Kurud Road, Kohka, Bhilai 490024, Chhattisgarh, India
| | - Madhulika Pradhan
- Department of Pharmaceutical Technology, Gracious College of Pharmacy, Abhanpur 493661, Chhattisgarh, India
| | - Mukesh Sharma
- Department of Pharmacognosy, Rungta College of Pharmaceutical Sciences and Research, Kurud Road, Kohka, Bhilai 490024, Chhattisgarh, India
| | - Ajazuddin
- Department of Pharmaceutics, Rungta College of Pharmaceutical Sciences and Research, Kurud Road, Kohka, Bhilai 490024, Chhattisgarh, India
| | - Hemant R Badwaik
- Department of Pharmaceutical Chemistry, Shri Shankaracharya Institute of Pharmaceutical Sciences and Research, Junwani, Bhilai 490020, Chhattisgarh, India
| | - Kartik T Nakhate
- Department of Pharmacology, Shri Vile Parle Kelavani Mandal's Institute of Pharmacy, Dhule 424001, Maharashtra, India
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19
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George AA, John SJ, Lucero LM, Eaton JB, Jaiswal E, Christensen SB, Gajewiak J, Watkins M, Cao Y, Olivera BM, Im W, McIntosh JM, Whiteaker P. Analogs of α-conotoxin PnIC selectively inhibit α7β2- over α7-only subtype nicotinic acetylcholine receptors via a novel allosteric mechanism. FASEB J 2024; 38:e23374. [PMID: 38161283 PMCID: PMC10782225 DOI: 10.1096/fj.202302079] [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: 10/12/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024]
Abstract
This study was undertaken to identify and characterize the first ligands capable of selectively identifying nicotinic acetylcholine receptors containing α7 and β2 subunits (α7β2-nAChR subtype). Basal forebrain cholinergic neurons express α7β2-nAChR. Here, they appear to mediate neuronal dysfunction induced by the elevated levels of oligomeric amyloid-β associated with early Alzheimer's disease. Additional work indicates that α7β2-nAChR are expressed across several further critically important cholinergic and GABAergic neuronal circuits within the central nervous system. Further studies, however, are significantly hindered by the inability of currently available ligands to distinguish heteromeric α7β2-nAChR from the closely related and more widespread homomeric α7-only-nAChR subtype. Functional screening using two-electrode voltage-clamp electrophysiology identified a family of α7β2-nAChR-selective analogs of α-conotoxin PnIC (α-CtxPnIC). A combined electrophysiology, functional kinetics, site-directed mutagenesis, and molecular dynamics approach was used to further characterize the α7β2-nAChR selectivity and site of action of these α-CtxPnIC analogs. We determined that α7β2-nAChR selectivity of α-CtxPnIC analogs arises from interactions at a site distinct from the orthosteric agonist-binding site shared between α7β2- and α7-only-nAChR. As numerous previously identified α-Ctx ligands are competitive antagonists of orthosteric agonist-binding sites, this study profoundly expands the scope of use of α-Ctx ligands (which have already provided important nAChR research and translational breakthroughs). More immediately, analogs of α-CtxPnIC promise to enable, for the first time, both comprehensive mapping of the distribution of α7β2-nAChR and detailed investigations of their physiological roles.
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Affiliation(s)
- Andrew A. George
- Department of Pharmacology and Toxicology, School of MedicineVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Sabin J. John
- Department of Pharmacology and Toxicology, School of MedicineVirginia Commonwealth UniversityRichmondVirginiaUSA
- Department of Life SciencesUniversity of BathBathUK
| | - Linda M. Lucero
- Department of NeurobiologyBarrow Neurological InstitutePhoenixArizonaUSA
| | - J. Brek Eaton
- Department of NeurobiologyBarrow Neurological InstitutePhoenixArizonaUSA
| | - Ekta Jaiswal
- Department of NeurobiologyBarrow Neurological InstitutePhoenixArizonaUSA
| | | | - Joanna Gajewiak
- School of Biological SciencesUniversity of UtahSalt Lake CityUtahUSA
| | - Maren Watkins
- School of Biological SciencesUniversity of UtahSalt Lake CityUtahUSA
| | - Yiwei Cao
- Department of ChemistryLehigh UniversityBethlehemPennsylvaniaUSA
| | | | - Wonpil Im
- Department of ChemistryLehigh UniversityBethlehemPennsylvaniaUSA
| | - J. Michael McIntosh
- School of Biological SciencesUniversity of UtahSalt Lake CityUtahUSA
- George E. Wahlen Veterans Affairs Medical CenterSalt Lake CityUtahUSA
- Department of PsychiatryUniversity of UtahSalt Lake CityUtahUSA
| | - Paul Whiteaker
- Department of Pharmacology and Toxicology, School of MedicineVirginia Commonwealth UniversityRichmondVirginiaUSA
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20
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Haufe Y, Kuruva V, Samanani Z, Lokaj G, Kamnesky G, Shadamarshan P, Shahoei R, Katz D, Sampson JM, Pusch M, Brik A, Nicke A, Leffler AE. Basic Residues at Position 11 of α-Conotoxin LvIA Influence Subtype Selectivity between α3β2 and α3β4 Nicotinic Receptors via an Electrostatic Mechanism. ACS Chem Neurosci 2023; 14:4311-4322. [PMID: 38051211 DOI: 10.1021/acschemneuro.3c00506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023] Open
Abstract
Understanding the determinants of α-conotoxin (α-CTX) selectivity for different nicotinic acetylcholine receptor (nAChR) subtypes is a prerequisite for the design of tool compounds to study nAChRs. However, selectivity optimization of these small, disulfide-rich peptides is difficult not only because of an absence of α-CTX/nAChR co-structures but also because it is challenging to predict how a mutation to an α-CTX will alter its potency and selectivity. As a prototypical system to investigate selectivity, we employed the α-CTX LvIA that is 25-fold selective for the α3β2 nAChR over the related α3β4 nAChR subtype, which is a target for nicotine addiction. Using two-electrode voltage clamp electrophysiology, we identified LvIA[D11R] that is 2-fold selective for the α3β4 nAChR, reversing the subtype preference. This effect is specifically due to the change in charge and not shape of LvIA[D11R], as substitution of D11 with citrulline retains selectivity for the α3β2 nAChR. Furthermore, LvIA[D11K] shows a stronger reversal, with 4-fold selectivity for the α3β4 nAChR. Motivated by these findings, using site-directed mutagenesis, we found that β2[K79A] (I79 on β4), but not β2[K78A] (N78 on β4), largely restores the potency of basic mutants at position 11. Finally, to understand the structural basis of this effect, we used AlphaFold2 to generate models of LvIA in complex with both nAChR subtypes. Both models confirm the plausibility of an electrostatic mechanism to explain the data and also reproduce a broad range of potency and selectivity structure-activity relationships for LvIA mutants, as measured using free energy perturbation simulations. Our work highlights how electrostatic interactions can drive α-CTX selectivity and may serve as a strategy for optimizing the selectivity of LvIA and other α-CTXs.
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Affiliation(s)
- Yves Haufe
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich 80539, Germany
| | - Veeresh Kuruva
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - Ziyana Samanani
- Schrödinger, Inc., 1540 Broadway, New York, New York 10036, United States
| | - Gonxhe Lokaj
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich 80539, Germany
| | - Guy Kamnesky
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - PranavKumar Shadamarshan
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich 80539, Germany
| | - Rezvan Shahoei
- Schrödinger, Inc., 1540 Broadway, New York, New York 10036, United States
| | - Dana Katz
- Schrödinger, Inc., 1540 Broadway, New York, New York 10036, United States
| | - Jared M Sampson
- Schrödinger, Inc., 1540 Broadway, New York, New York 10036, United States
| | - Michael Pusch
- Istituto di Biofisica, CNR, Via De Marini 6, Genova 16149, Italy
| | - Ashraf Brik
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - Annette Nicke
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich 80539, Germany
| | - Abba E Leffler
- Schrödinger, Inc., 1540 Broadway, New York, New York 10036, United States
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21
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Raisch T, Raunser S. The modes of action of ion-channel-targeting neurotoxic insecticides: lessons from structural biology. Nat Struct Mol Biol 2023; 30:1411-1427. [PMID: 37845413 DOI: 10.1038/s41594-023-01113-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 08/31/2023] [Indexed: 10/18/2023]
Abstract
Insecticides are indispensable tools for plant protection in modern agriculture. Despite having highly heterogeneous structures, many neurotoxic insecticides use similar principles to inhibit or deregulate neuronal ion channels. Insecticides targeting pentameric ligand-gated channels are structural mimetics of neurotransmitters or manipulate and deregulate the proteins. Those binding to (pseudo-)tetrameric voltage-gated(-like) channels, on the other hand, are natural or synthetic compounds that directly block the ion-conducting pore or prevent conformational changes in the transmembrane domain necessary for opening and closing the pore. The use of a limited number of inhibition mechanisms can be problematic when resistances arise and become more widespread. Therefore, there is a rising interest in the development of insecticides with novel mechanisms that evade resistance and are pest-insect-specific. During the last decade, most known insecticide targets, many with bound compounds, have been structurally characterized, bringing the rational design of novel classes of agrochemicals within closer reach than ever before.
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Affiliation(s)
- Tobias Raisch
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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22
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Mohamad FH, Mohamad Jamali MA, Che Has AT. Structure-function Studies of GABA (A) Receptors and Related computer-aided Studies. J Mol Neurosci 2023; 73:804-817. [PMID: 37750966 DOI: 10.1007/s12031-023-02158-3] [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: 08/03/2023] [Accepted: 09/12/2023] [Indexed: 09/27/2023]
Abstract
The γ-aminobutyric acid type A receptor (GABA (A) receptor) is a membrane protein activated by the neurotransmitter GABA. Structurally, this major inhibitory neurotransmitter receptor in the human central nervous system is a pentamer that can be built from a selection of 19 subunits consisting of α(1,2,3,4,5 or 6), β (1,2 or 3), γ (1,2 or 3), ρ (1,2 or 3), and δ, π, θ, and ε. This creates several possible pentameric arrangements, which also influence the pharmacological and physiological properties of the receptor. The complexity and heterogeneity of the receptors are further increased by the addition of short and long splice variants in several subunits and the existence of multiple allosteric binding sites and expansive ligands that can bind to the receptors. Therefore, a comprehensive understanding of the structure and function of the receptors is required to gain novel insights into the consequences of receptor dysfunction and subsequent drug development studies. Notably, advancements in computational-aided studies have facilitated the elucidation of residual interactions and exploring energy binding, which may otherwise be challenging to investigate. In this review, we aim to summarize the current understanding of the structure and function of GABA (A) receptors obtained from advancements in computational-aided applications.
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Affiliation(s)
- Fatin H Mohamad
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia
| | - Muhamad Arif Mohamad Jamali
- Faculty of Science and Technology, Universiti Sains Islam Malaysia, Bandar Baru Nilai, 71800, Nilai, Negeri Sembilan, Malaysia
| | - Ahmad Tarmizi Che Has
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, 16150 Kota Bharu, Kelantan, Malaysia.
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23
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Prevost MS, Barilone N, Dejean de la Bâtie G, Pons S, Ayme G, England P, Gielen M, Bontems F, Pehau-Arnaudet G, Maskos U, Lafaye P, Corringer PJ. An original potentiating mechanism revealed by the cryo-EM structures of the human α7 nicotinic receptor in complex with nanobodies. Nat Commun 2023; 14:5964. [PMID: 37749098 PMCID: PMC10520083 DOI: 10.1038/s41467-023-41734-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 09/15/2023] [Indexed: 09/27/2023] Open
Abstract
The human α7 nicotinic receptor is a pentameric channel mediating cellular and neuronal communication. It has attracted considerable interest in designing ligands for the treatment of neurological and psychiatric disorders. To develop a novel class of α7 ligands, we recently generated two nanobodies named E3 and C4, acting as positive allosteric modulator and silent allosteric ligand, respectively. Here, we solved the cryo-electron microscopy structures of the nanobody-receptor complexes. E3 and C4 bind to a common epitope involving two subunits at the apex of the receptor. They form by themselves a symmetric pentameric assembly that extends the extracellular domain. Unlike C4, the binding of E3 drives an agonist-bound conformation of the extracellular domain in the absence of an orthosteric agonist, and mutational analysis shows a key contribution of an N-linked sugar moiety in mediating E3 potentiation. The nanobody E3, by remotely controlling the global allosteric conformation of the receptor, implements an original mechanism of regulation that opens new avenues for drug design.
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Affiliation(s)
- Marie S Prevost
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France.
| | - Nathalie Barilone
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France
| | | | - Stéphanie Pons
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Integrative Neurobiology of Cholinergic Systems Unit, Paris, France
| | - Gabriel Ayme
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Antibody Engineering Platform, Paris, France
| | - Patrick England
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Molecular Biophysics Platform, Paris, France
| | - Marc Gielen
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France
- Sorbonne Université, Paris, France
| | - François Bontems
- Institut Pasteur, Université Paris Cité, CNRS UMR 3569, Structural Virology Unit, Paris, France
- Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, Université Paris Saclay, Gif-sur-Yvette, France
| | - Gérard Pehau-Arnaudet
- Institut Pasteur, Université Paris Cité, Ultrastructural Bioimaging Core Facility, Paris, France
| | - Uwe Maskos
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Integrative Neurobiology of Cholinergic Systems Unit, Paris, France
| | - Pierre Lafaye
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Antibody Engineering Platform, Paris, France
| | - Pierre-Jean Corringer
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France.
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24
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Noonan JD, Beech RN. Two residues determine nicotinic acetylcholine receptor requirement for RIC-3. Protein Sci 2023; 32:e4718. [PMID: 37417463 PMCID: PMC10443321 DOI: 10.1002/pro.4718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/11/2023] [Accepted: 06/26/2023] [Indexed: 07/08/2023]
Abstract
Nicotinic acetylcholine receptors (N-AChRs) mediate fast synaptic signaling and are members of the pentameric ligand-gated ion channel (pLGIC) family. They rely on a network of accessory proteins in vivo for correct formation and transport to the cell surface. Resistance to cholinesterase 3 (RIC-3) is an endoplasmic reticulum protein that physically interacts with nascent pLGIC subunits and promotes their oligomerization. It is not known why some N-AChRs require RIC-3 in heterologous expression systems, whereas others do not. Previously we reported that the ACR-16 N-AChR from the parasitic nematode Dracunculus medinensis does not require RIC-3 in Xenopus laevis oocytes. This is unusual because all other nematode ACR-16, like the closely related Ascaris suum ACR-16, require RIC-3. Their high sequence similarity limits the number of amino acids that may be responsible, and the goal of this study was to identify them. A series of chimeras and point mutations between A. suum and D. medinensis ACR-16, followed by functional characterization with electrophysiology, identified two residues that account for a majority of the receptor requirement for RIC-3. ACR-16 with R/K159 in the cys-loop and I504 in the C-terminal tail did not require RIC-3 for functional expression. Mutating either of these to R/K159E or I504T, residues found in other nematode ACR-16, conferred a RIC-3 requirement. Our results agree with previous studies showing that these regions interact and are involved in receptor synthesis. Although it is currently unclear what precise mechanism they regulate, these residues may be critical during specific subunit folding and/or assembly cascades that RIC-3 may promote.
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Affiliation(s)
- Jennifer D. Noonan
- Institute of Parasitology, Macdonald Campus, McGill UniversityMontrealQuébecCanada
| | - Robin N. Beech
- Institute of Parasitology, Macdonald Campus, McGill UniversityMontrealQuébecCanada
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25
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Grillberger K, Cöllen E, Trivisani CI, Blum J, Leist M, Ecker GF. Structural Insights into Neonicotinoids and N-Unsubstituted Metabolites on Human nAChRs by Molecular Docking, Dynamics Simulations, and Calcium Imaging. Int J Mol Sci 2023; 24:13170. [PMID: 37685977 PMCID: PMC10487998 DOI: 10.3390/ijms241713170] [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: 07/28/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 09/10/2023] Open
Abstract
Neonicotinoid pesticides were initially designed in order to achieve species selectivity on insect nicotinic acetylcholine receptors (nAChRs). However, concerns arose when agonistic effects were also detected in human cells expressing nAChRs. In the context of next-generation risk assessments (NGRAs), new approach methods (NAMs) should replace animal testing where appropriate. Herein, we present a combination of in silico and in vitro methodologies that are used to investigate the potentially toxic effects of neonicotinoids and nicotinoid metabolites on human neurons. First, an ensemble docking study was conducted on the nAChR isoforms α7 and α3β4 to assess potential crucial molecular initiating event (MIE) interactions. Representative docking poses were further refined using molecular dynamics (MD) simulations and binding energy calculations using implicit solvent models. Finally, calcium imaging on LUHMES neurons confirmed a key event (KE) downstream of the MIE. This method was also used to confirm the predicted agonistic effect of the metabolite descyano-thiacloprid (DCNT).
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Affiliation(s)
- Karin Grillberger
- Department of Pharmaceutical Sciences, University of Vienna, 1090 Vienna, Austria
| | - Eike Cöllen
- In Vitro Toxicology and Biomedicine, University of Konstanz, 78457 Konstanz, Germany
| | | | - Jonathan Blum
- In Vitro Toxicology and Biomedicine, University of Konstanz, 78457 Konstanz, Germany
| | - Marcel Leist
- In Vitro Toxicology and Biomedicine, University of Konstanz, 78457 Konstanz, Germany
| | - Gerhard F. Ecker
- Department of Pharmaceutical Sciences, University of Vienna, 1090 Vienna, Austria
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26
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Liu X, Wang W. Gating mechanism of the human α1β GlyR by glycine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.08.552474. [PMID: 37609197 PMCID: PMC10441291 DOI: 10.1101/2023.08.08.552474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Glycine receptors (GlyRs) are members of the Cys-loop receptors that constitute a major portion of neurotransmitter receptors in the human nervous system. GlyRs are found in the spinal cord and brain mediating locomotive, sensory and cognitive functions, and are targets for pharmaceutical development. GlyRs share a general gating scheme with Cys-loop receptor family members, but the underlying mechanism is unclear. Recent resolution of heteromeric GlyRs structures in multiple functional states identified an invariable 4:1 α:β subunit stoichiometry and provided snapshots in the gating cycle, challenging previous beliefs and raising the fundamental questions of how α and β subunit functions in glycine binding and channel activation. In addition, how a single glycine-bound extracellular domain conformation leads to structurally and functionally different open and desensitized states remained enigmatic. In this study, we characterized in detail equilibrium properties as well as the transition kinetics between functional states. We show that while all allosteric sites bind cooperatively to glycine, occupation of 2 sites at the α-α interfaces is necessary and sufficient for GlyR activation. We also demonstrate differential glycine concentration dependence of desensitization rate, extent, and its recovery, which suggests separate but concerted roles of ligand-binding and ionophore reorganization. Based on these observations and available structural information, we developed a comprehensive quantitative gating model that accurately predicts both equilibrium and kinetical properties throughout glycine gating cycle. This model likely applies generally to the Cys-loop receptor family and informs on pharmaceutical endeavors in function modulation of this receptor family.
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27
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Pettersen JM, Yang Y, Robinson AS. Advances in nanodisc platforms for membrane protein purification. Trends Biotechnol 2023; 41:1041-1054. [PMID: 36935323 DOI: 10.1016/j.tibtech.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/07/2023] [Accepted: 02/20/2023] [Indexed: 03/19/2023]
Abstract
Membrane scaffold protein nanodiscs (MSPNDs) are an invaluable tool for improving purified membrane protein (MP) stability and activity compared to traditional micellar methods, thus enabling an increase in high-resolution MP structures, particularly in concert with cryogenic electron microscopy (cryo-EM) approaches. In this review we highlight recent advances and breakthroughs in MSPND methodology and applications. We also introduce and discuss saposin-lipoprotein nanoparticles (salipros) and copolymer nanodiscs which have recently emerged as authentic MSPND alternatives. We compare the advantages and disadvantages of MSPNDs, salipros, and copolymer nanodisc technologies to highlight potential opportunities for using each platform for MP purification and characterization.
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Affiliation(s)
- John M Pettersen
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Yaxin Yang
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Anne S Robinson
- Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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28
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Matera C, Papotto C, Dallanoce C, De Amici M. Advances in small molecule selective ligands for heteromeric nicotinic acetylcholine receptors. Pharmacol Res 2023; 194:106813. [PMID: 37302724 DOI: 10.1016/j.phrs.2023.106813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/26/2023] [Accepted: 06/02/2023] [Indexed: 06/13/2023]
Abstract
The study of nicotinic acetylcholine receptors (nAChRs) has significantly progressed in the last decade, due to a) the improved techniques available for structural studies; b) the identification of ligands interacting at orthosteric and allosteric recognition sites on the nAChR proteins, able to tune channel conformational states; c) the better functional characterization of receptor subtypes/subunits and their therapeutic potential; d) the availability of novel pharmacological agents able to activate or block nicotinic-mediated cholinergic responses with subtype or stoichiometry selectivity. The copious literature on nAChRs is related to the pharmacological profile of new, promising subtype selective derivatives as well as the encouraging preclinical and early clinical evaluation of known ligands. However, recently approved therapeutic derivatives are still missing, and examples of ligands discontinued in advanced CNS clinical trials include drug candidates acting at both neuronal homomeric and heteromeric receptors. In this review, we have selected heteromeric nAChRs as the target and comment on literature reports of the past five years dealing with the discovery of new small molecule ligands or the advanced pharmacological/preclinical investigation of more promising compounds. The results obtained with bifunctional nicotinic ligands and a light-activated ligand as well as the applications of promising radiopharmaceuticals for heteromeric subtypes are also discussed.
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Affiliation(s)
- Carlo Matera
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy
| | - Claudio Papotto
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy
| | - Clelia Dallanoce
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy
| | - Marco De Amici
- Department of Pharmaceutical Sciences, Medicinal Chemistry Section "Pietro Pratesi", University of Milan, Via Luigi Mangiagalli 25, 20133 Milan, Italy.
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29
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Hernando G, Turani O, Rodriguez Araujo N, Bouzat C. The diverse family of Cys-loop receptors in Caenorhabditis elegans: insights from electrophysiological studies. Biophys Rev 2023; 15:733-750. [PMID: 37681094 PMCID: PMC10480131 DOI: 10.1007/s12551-023-01080-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/18/2023] [Indexed: 09/09/2023] Open
Abstract
Cys-loop receptors integrate a large family of pentameric ligand-gated ion channels that mediate fast ionotropic responses in vertebrates and invertebrates. Their vital role in converting neurotransmitter recognition into an electrical impulse makes these receptors essential for a great variety of physiological processes. In vertebrates, the Cys-loop receptor family includes the cation-selective channels, nicotinic acetylcholine and 5-hydroxytryptamine type 3 receptors, and the anion-selective channels, GABAA and glycine receptors, whereas in invertebrates, the repertoire is significantly larger. The free-living nematode Caenorhabditis elegans has the largest known Cys-loop receptor family as well as unique receptors that are absent in vertebrates and constitute attractive targets for anthelmintic drugs. Given the large number and variety of Cys-loop receptor subunits and the multiple possible ways of subunit assembly, C. elegans offers a large diversity of receptors although only a limited number of them have been characterized to date. C. elegans has emerged as a powerful model for the study of the nervous system and human diseases as well as a model for antiparasitic drug discovery. This nematode has also shown promise in the pharmaceutical industry search for new therapeutic compounds. C. elegans is therefore a powerful model organism to explore the biology and pharmacology of Cys-loop receptors and their potential as targets for novel therapeutic interventions. In this review, we provide a comprehensive overview of what is known about the function of C. elegans Cys-loop receptors from an electrophysiological perspective.
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Affiliation(s)
- Guillermina Hernando
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Ornella Turani
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Noelia Rodriguez Araujo
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
| | - Cecilia Bouzat
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Investigaciones Bioquímicas de Bahía Blanca, Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina
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30
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Xu P, Zhang P, Zhu X, Wu Y, Harvey PJ, Kaas Q, Zhangsun D, Craik DJ, Luo S. Structure-Activity Relationships of Alanine Scan Mutants αO-Conotoxins GeXIVA[1,2] and GeXIVA[1,4]. J Med Chem 2023. [PMID: 37464764 DOI: 10.1021/acs.jmedchem.3c01023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
αO-Conotoxin GeXIVA is a selective α9α10 nicotinic acetylcholine receptor (nAChR) inhibitor displaying two disulfide bonds that can form three isomers. The bead (GeXIVA[1,2]) and ribbon (GeXIVA[1,4]) isomers possess the highest activity on rat and human α9α10 nAChRs. However, the molecular mechanism by which they inhibit the α9α10 nAChR is unknown. Here, an alanine scan of GeXIVA was used to elucidate key interactions between the peptides and the α9α10 nAChR. The majority of GeXIVA[1,2] analogues preserved affinity at α9α10 nAChR, but [R17A]GeXIVA[1,2] enhanced selectivity on the α9α10 nAChR. The I23A replacement of GeXIVA[1,4] increased activity at both rat and human α9α10 nAChRs by 10-fold. Surprisingly, these results do not support the molecular model of an interaction in the orthosteric binding site proposed previously, but rather may involve allosteric coupling with the voltage-sensitive domain of the α9α10 nAChR. These results could help to guide further development of GeXIVA analogues as analgesics.
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Affiliation(s)
- Pan Xu
- School of Medicine, Guangxi University, Nanning 530004, China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Panpan Zhang
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Yong Wu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Dongting Zhangsun
- School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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31
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Strikwerda JR, Natarajan K, Sine SM. Impact on AChR open channel noise by pore-peripheral salt bridge depends on voltage and divalent cations. Biophys J 2023; 122:2430-2444. [PMID: 37113056 PMCID: PMC10322898 DOI: 10.1016/j.bpj.2023.04.024] [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: 12/02/2022] [Revised: 02/16/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023] Open
Abstract
Mechanisms behind the fluctuations in the ionic current through single acetylcholine receptor (AChR) channels have remained elusive. In a recent study of muscle AChR we showed that mutation of a conserved intramembrane salt bridge in the β- and δ-subunits markedly increased fluctuations in the open channel current that extended from low to high frequency. Here, we show that extracellular divalent cations reduce the high-frequency fluctuations and increase the low-frequency fluctuations. The low-frequency fluctuations are shown to arise from steps between two current levels, with the ratio of the time at each level changing e-fold for a 70 mV increase in membrane potential, indicating modulation by a charged element within the membrane field. Increasing the charge on the ion selectivity filter biases the ratio of current levels equivalent to a 50 mV increase in membrane potential but does not alter the voltage dependence of the ratio. The magnitudes of the voltage dependence and voltage bias allow estimates of the distance between the ion selectivity filter and the voltage-sensing element. Studies with either calcium or magnesium show that the two divalent cations synergize to increase the low-frequency fluctuations, whereas they act independently to decrease the high-frequency fluctuations, indicating multiple divalent cation binding sites. Molecular dynamics simulations applied to the structure of the Torpedo AChR reveal that mutation of the salt bridge alters the equilibrium positions and dynamics of residues local to the site of the mutation and within the adjacent ion selectivity filter in a calcium-dependent manner. Thus, disruption of a conserved intramembrane salt bridge in the muscle AChR induces fluctuations in open channel current that are sensitive to divalent cation binding at multiple sites and modulated by a charged element within the membrane field.
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Affiliation(s)
- John R Strikwerda
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Rochester, Minnesota
| | - Kathiresan Natarajan
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Rochester, Minnesota
| | - Steven M Sine
- Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Rochester, Minnesota; Department of Molecular Pharmacology and Experimental Therapeutics, Rochester, Minnesota; Department of Neurology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota.
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Do HQ, Jansen M. Binding motif for RIC-3 chaperon protein in serotonin type 3A receptors. J Gen Physiol 2023; 155:e202213305. [PMID: 37026993 PMCID: PMC10083716 DOI: 10.1085/jgp.202213305] [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: 12/03/2022] [Revised: 03/09/2023] [Accepted: 03/21/2023] [Indexed: 04/08/2023] Open
Abstract
Serotonin or 5-hydroxytryptamine type 3 (5-HT3) receptors belong to the family of pentameric ligand-gated ion channels (pLGICs) that are therapeutic targets for psychiatric disorders and neurological diseases. Due to structural conservation and significant sequence similarities of pLGICs' extracellular and transmembrane domains, clinical trials for drug candidates targeting these two domains have been hampered by off-subunit modulation. With the present study, we explore the interaction interface of the 5-HT3A subunit intracellular domain (ICD) with the resistance to inhibitors of choline esterase (RIC-3) protein. Previously, we have shown that RIC-3 interacts with the L1-MX segment of the ICD fused to maltose-binding protein. In the present study, synthetic L1-MX-based peptides and Ala-scanning identify positions W347, R349, and L353 as critical for binding to RIC-3. Complementary studies using full-length 5-HT3A subunits confirm that the identified Ala substitutions reduce the RIC-3-mediated modulation of functional surface expression. Additionally, we find and characterize a duplication of the binding motif, DWLR…VLDR, present in both the MX-helix and the transition between the ICD MA-helix and transmembrane segment M4. Analogous Ala substitutions at W447, R449, and L454 disrupt MAM4-peptide RIC-3 interactions and reduce modulation of functional surface expression. In summary, we identify the binding motif for RIC-3 in 5-HT3A subunits at two locations in the ICD, one in the MX-helix and one at the MAM4-helix transition.
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Affiliation(s)
- Hoa Quynh Do
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Michaela Jansen
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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Li Q, Nemecz Á, Aymé G, Dejean de la Bâtie G, Prevost MS, Pons S, Barilone N, Baachaoui R, Maskos U, Lafaye P, Corringer PJ. Generation of nanobodies acting as silent and positive allosteric modulators of the α7 nicotinic acetylcholine receptor. Cell Mol Life Sci 2023; 80:164. [PMID: 37231269 DOI: 10.1007/s00018-023-04779-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/28/2023] [Accepted: 04/07/2023] [Indexed: 05/27/2023]
Abstract
The α7 nicotinic acetylcholine receptor (nAChR), a potential drug target for treating cognitive disorders, mediates communication between neuronal and non-neuronal cells. Although many competitive antagonists, agonists, and partial-agonists have been found and synthesized, they have not led to effective therapeutic treatments. In this context, small molecules acting as positive allosteric modulators binding outside the orthosteric, acetylcholine, site have attracted considerable interest. Two single-domain antibody fragments, C4 and E3, against the extracellular domain of the human α7-nAChR were generated through alpaca immunization with cells expressing a human α7-nAChR/mouse 5-HT3A chimera, and are herein described. They bind to the α7-nAChR but not to the other major nAChR subtypes, α4β2 and α3β4. E3 acts as a slowly associating positive allosteric modulator, strongly potentiating the acetylcholine-elicited currents, while not precluding the desensitization of the receptor. An E3-E3 bivalent construct shows similar potentiating properties but displays very slow dissociation kinetics conferring quasi-irreversible properties. Whereas, C4 does not alter the receptor function, but fully inhibits the E3-evoked potentiation, showing it is a silent allosteric modulator competing with E3 binding. Both nanobodies do not compete with α-bungarotoxin, localizing at an allosteric extracellular binding site away from the orthosteric site. The functional differences of each nanobody, as well as the alteration of functional properties through nanobody modifications indicate the importance of this extracellular site. The nanobodies will be useful for pharmacological and structural investigations; moreover, they, along with the extracellular site, have a direct potential for clinical applications.
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Affiliation(s)
- Qimeng Li
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Antibody Engineering Platform, Paris, France
- Lanzhou Institute of Biological Product Co., Lanzhou, China
- Sorbonne Université, Collège Doctoral, Paris, France
| | - Ákos Nemecz
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France.
| | - Gabriel Aymé
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Antibody Engineering Platform, Paris, France.
| | | | - Marie S Prevost
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France
| | - Stéphanie Pons
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Integrative Neurobiology of Cholinergic Systems Unit, Paris, France
| | - Nathalie Barilone
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France
| | - Rayen Baachaoui
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Antibody Engineering Platform, Paris, France
| | - Uwe Maskos
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Integrative Neurobiology of Cholinergic Systems Unit, Paris, France
| | - Pierre Lafaye
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Antibody Engineering Platform, Paris, France
| | - Pierre-Jean Corringer
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Channel-Receptors Unit, Paris, France.
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Pliushcheuskaya P, Künze G. Recent Advances in Computer-Aided Structure-Based Drug Design on Ion Channels. Int J Mol Sci 2023; 24:ijms24119226. [PMID: 37298178 DOI: 10.3390/ijms24119226] [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: 04/19/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Ion channels play important roles in fundamental biological processes, such as electric signaling in cells, muscle contraction, hormone secretion, and regulation of the immune response. Targeting ion channels with drugs represents a treatment option for neurological and cardiovascular diseases, muscular degradation disorders, and pathologies related to disturbed pain sensation. While there are more than 300 different ion channels in the human organism, drugs have been developed only for some of them and currently available drugs lack selectivity. Computational approaches are an indispensable tool for drug discovery and can speed up, especially, the early development stages of lead identification and optimization. The number of molecular structures of ion channels has considerably increased over the last ten years, providing new opportunities for structure-based drug development. This review summarizes important knowledge about ion channel classification, structure, mechanisms, and pathology with the main focus on recent developments in the field of computer-aided, structure-based drug design on ion channels. We highlight studies that link structural data with modeling and chemoinformatic approaches for the identification and characterization of new molecules targeting ion channels. These approaches hold great potential to advance research on ion channel drugs in the future.
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Affiliation(s)
- Palina Pliushcheuskaya
- Institute for Drug Discovery, Medical Faculty, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Georg Künze
- Institute for Drug Discovery, Medical Faculty, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany
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Xie T, Qin Y, Zhao J, Dong J, Qi P, Zhang P, Zhangsun D, Zhu X, Yu J, Luo S. Molecular Determinants of Species Specificity of α-Conotoxin TxIB towards Rat and Human α6/α3β4 Nicotinic Acetylcholine Receptors. Int J Mol Sci 2023; 24:ijms24108618. [PMID: 37239959 DOI: 10.3390/ijms24108618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/05/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Conotoxins are widely distributed and important for studying ligand-gated ion channels. TxIB, a conotoxin consisting of 16 amino acids derived from Conus textile, is a unique selective ligand that blocks rat α6/α3β2β3 nAChR (IC50 = 28 nM) without affecting other rat subtypes. However, when the activity of TxIB against human nAChRs was examined, it was unexpectedly found that TxIB had a significant blocking effect on not only human α6/α3β2β3 nAChR but also human α6/α3β4 nAChR, with an IC50 of 537 nM. To investigate the molecular mechanism of this species specificity and to establish a theoretical basis for drug development studies of TxIB and its analogs, different amino acid residues between human and rat α6/α3 and β4 nAChR subunits were identified. Each residue of the human species was then substituted with the corresponding residue of the rat species via PCR-directed mutagenesis. The potencies of TxIB towards the native α6/α3β4 nAChRs and their mutants were evaluated through electrophysiological experiments. The results showed that the IC50 of TxIB against h[α6V32L, K61R/α3]β4L107V, V115I was 22.5 μM, a 42-fold decrease in potency compared to the native hα6/α3β4 nAChR. Val-32 and Lys-61 in the human α6/α3 subunit and Leu-107 and Val-115 in the human β4 subunit, together, were found to determine the species differences in the α6/α3β4 nAChR. These results also demonstrate that the effects of species differences between humans and rats should be fully considered when evaluating the efficacy of drug candidates targeting nAChRs in rodent models.
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Affiliation(s)
- Ting Xie
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Yuan Qin
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Jinyuan Zhao
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Jianying Dong
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Panpan Qi
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Panpan Zhang
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China
| | - Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Jinpeng Yu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China
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Pechlivanidou M, Ninou E, Karagiorgou K, Tsantila A, Mantegazza R, Francesca A, Furlan R, Dudeck L, Steiner J, Tzartos J, Tzartos S. Autoimmunity to Neuronal Nicotinic Acetylcholine Receptors. Pharmacol Res 2023; 192:106790. [PMID: 37164280 DOI: 10.1016/j.phrs.2023.106790] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 04/30/2023] [Accepted: 05/05/2023] [Indexed: 05/12/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are widely expressed in many and diverse cell types, participating in various functions of cells, tissues and systems. In this review, we focus on the autoimmunity against neuronal nAChRs, the specific autoantibodies and their mechanisms of pathological action in selected autoimmune diseases. We summarize the current relevant knowledge from human diseases as well as from experimental models of autoimmune neurological disorders related to antibodies against neuronal nAChR subunits. Despite the well-studied high immunogenicity of the muscle nAChRs where autoantibodies are the main pathogen of myasthenia gravis, autoimmunity to neuronal nAChRs seems infrequent, except for the autoantibodies to the ganglionic receptor, the α3 subunit containing nAChR (α3-nAChR), which are detected and are likely pathogenic in Autoimmune Autonomic Ganglionopathy (AAG). We describe the detection, presence and function of these antibodies and especially the recent development of a cell-based assay (CBA) which, contrary to until recently available assays, is highly specific for AAG. Rare reports of autoantibodies to the other neuronal nAChR subtypes include a few cases of antibodies to α7 and/or α4β2 nAChRs in Rasmussen encephalitis, schizophrenia, autoimmune meningoencephalomyelitis, and in some myasthenia gravis patients with concurrent CNS symptoms. Neuronal-type nAChRs are also present in several non-excitable tissues, however the presence and possible role of antibodies against them needs further verification. It is likely that the future development of more sensitive and disease-specific assays would reveal that neuronal nAChR autoantibodies are much more frequent and may explain the mechanisms of some seronegative autoimmune diseases.
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Affiliation(s)
| | | | - Katerina Karagiorgou
- Tzartos NeuroDiagnostics, Athens, Greece; Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | | | - Renato Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Andreetta Francesca
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta, Milan, Italy
| | - Raffaello Furlan
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Rozzano, Milan, Italy; Clinical and Research Center - IRCCS, Humanitas University, Rozzano, Milan, Italy
| | - Leon Dudeck
- Department of Psychiatry and Psychotherapy, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; Laboratory of Translational Psychiatry, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Johann Steiner
- Department of Psychiatry and Psychotherapy, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; Laboratory of Translational Psychiatry, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany; Center for Health and Medical Prevention (CHaMP), Magdeburg, Germany; German Center for Mental Health DZPG, Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying Mental Health C-I-R-C, Halle-Jena-Magdeburg, Germany
| | - John Tzartos
- 2(nd) Department of Neurology, School of Medicine, National and Kapodistrian University of Athens, "Attikon" University Hospital, Athens, Greece.
| | - Socrates Tzartos
- Tzartos NeuroDiagnostics, Athens, Greece; Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece; Department of Pharmacy, University of Patras, Patras, Greece.
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Quesada O, González-Nieves JE, Colón J, Maldonado-Hernández R, González-Freire C, Acevedo-Cintrón J, Rosado-Millán ID, Lasalde-Dominicci JA. Assessment of Purity, Functionality, Stability, and Lipid Composition of Cyclofos-nAChR-Detergent Complexes from Torpedo californica Using Lipid Matrix and Macroscopic Electrophysiology. J Membr Biol 2023; 256:271-285. [PMID: 37140614 PMCID: PMC10157581 DOI: 10.1007/s00232-023-00285-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023]
Abstract
The main objective of the present study was to find detergents that can maintain the functionality and stability of the Torpedo californica nicotinic acetylcholine receptor (Tc-nAChR). We examined the functionality, stability, and purity analysis of affinity-purified Tc-nAChR solubilized in detergents from the Cyclofos (CF) family [cyclofoscholine 4 (CF-4), cyclofoscholine 6 (CF-6), and cyclofloscholine 7 (CF-7)]. The functionality of the CF-Tc-nAChR-detergent complex (DC) was evaluated using the Two Electrode Voltage Clamp (TEVC) method. To assess stability, we used the florescence recovery after photobleaching (FRAP) in Lipidic Cubic Phase (LCP) methodology. We also performed a lipidomic analysis using Ultra-Performance Liquid Chromatography (UPLC) coupled to electrospray ionization mass spectrometry (ESI-MS/MS) to evaluate the lipid composition of the CF-Tc-nAChR-DCs. The CF-4-Tc-nAChR-DC displayed a robust macroscopic current (- 200 ± 60 nA); however, the CF-6-Tc-nAChR-DC and CF-7-Tc-nAChR-DC displayed significant reductions in the macroscopic currents. The CF-6-Tc-nAChR and CF-4-Tc-nAChR displayed higher fractional florescence recovery. Addition of cholesterol produced a mild enhancement of the mobile fraction on the CF-6-Tc-nAChR. The lipidomic analysis revealed that the CF-7-Tc-nAChR-DC displayed substantial delipidation, consistent with the lack of stability and functional response of this complex. Although the CF-6-nAChR-DC complex retained the largest amount of lipids, it showed a loss of six lipid species [SM(d16:1/18:0); PC(18:2/14:1); PC(14:0/18:1); PC(16:0/18:1); PC(20:5/20:4), and PC(20:4/20:5)] that are present in the CF-4-nAChR-DC. Overall, the CF-4-nAChR displayed robust functionality, significant stability, and the best purity among the three CF detergents; therefore, CF-4 is a suitable candidate to prepare Tc-nAChR crystals for structural studies.
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Affiliation(s)
- Orestes Quesada
- Department of Physical Sciences, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA.
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA.
- Molecular Science Center, University of Puerto Rico, San Juan, PR, USA.
| | | | - José Colón
- Department of Pharmaceutical Sciences, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA
- Molecular Science Center, University of Puerto Rico, San Juan, PR, USA
| | - Rafael Maldonado-Hernández
- Department of Biology, University of Puerto Rico, Ponce Campus, Ponce, PR, USA
- Molecular Science Center, University of Puerto Rico, San Juan, PR, USA
| | - Carol González-Freire
- Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - Jesús Acevedo-Cintrón
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - Irvin D Rosado-Millán
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA
| | - José A Lasalde-Dominicci
- Department of Biology, University of Puerto Rico, Río Piedras Campus, San Juan, PR, USA.
- Department of Pharmaceutical Sciences, Medical Sciences Campus, University of Puerto Rico, San Juan, PR, USA.
- Molecular Science Center, University of Puerto Rico, San Juan, PR, USA.
- Institute of Neurobiology, University of Puerto Rico, Medical Science Campus, San Juan, PR, USA.
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Gao Y, Amon JD, Artzi L, Ramírez-Guadiana FH, Brock KP, Cofsky JC, Marks DS, Kruse AC, Rudner DZ. Bacterial spore germination receptors are nutrient-gated ion channels. Science 2023; 380:387-391. [PMID: 37104613 PMCID: PMC11154005 DOI: 10.1126/science.adg9829] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/29/2023] [Indexed: 04/29/2023]
Abstract
Bacterial spores resist antibiotics and sterilization and can remain metabolically inactive for decades, but they can rapidly germinate and resume growth in response to nutrients. Broadly conserved receptors embedded in the spore membrane detect nutrients, but how spores transduce these signals remains unclear. Here, we found that these receptors form oligomeric membrane channels. Mutations predicted to widen the channel initiated germination in the absence of nutrients, whereas those that narrow it prevented ion release and germination in response to nutrients. Expressing receptors with widened channels during vegetative growth caused loss of membrane potential and cell death, whereas the addition of germinants to cells expressing wild-type receptors triggered membrane depolarization. Therefore, germinant receptors act as nutrient-gated ion channels such that ion release initiates exit from dormancy.
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Affiliation(s)
- Yongqiang Gao
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
| | - Jeremy D. Amon
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
- Present Address: Moderna Genomics, 200 Technology Square, Cambridge MA 02139
| | - Lior Artzi
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
- Present Address: Evolved By Nature, 196 Boston Ave, Medford MA 02155
| | | | - Kelly P. Brock
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston MA 02115
- Present Address: Kernal Biologics, 238 Main Street, Cambrdige MA 02142
| | - Joshua C. Cofsky
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston MA 02115
| | - Deborah S. Marks
- Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston MA 02115
| | - Andrew C. Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston MA 02115
| | - David Z. Rudner
- Department of Microbiology, Harvard Medical ScF(2hool, 77 Avenue Louis Pasteur, Boston MA 02115
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Sanders VR, Millar NS. Potentiation and allosteric agonist activation of α7 nicotinic acetylcholine receptors: binding sites and hypotheses. Pharmacol Res 2023; 191:106759. [PMID: 37023990 DOI: 10.1016/j.phrs.2023.106759] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 04/07/2023]
Abstract
Considerable progress has been made in recent years towards the identification and characterisation of novel subtype-selective modulators of nicotinic acetylcholine receptors (nAChRs). In particular, this has focussed on modulators of α7 nAChRs, a nAChR subtype that has been identified as a target for drug discovery in connection with a range of potential therapeutic applications. This review focusses upon α7-selective modulators that bind to receptor sites other than the extracellular 'orthosteric' agonist binding site for the endogenous agonist acetylcholine (ACh). Such compounds include those that are able to potentiate responses evoked by orthosteric agonists such as ACh (positive allosteric modulators; PAMs) and those that are able to activate α7 nAChRs by direct allosteric activation in the absence of an orthosteric agonist (allosteric agonists or 'ago-PAMs'). There has been considerable debate about the mechanism of action of α7-selective PAMs and allosteric agonists, much of which has centred around identifying the location of their binding sites on α7 nAChRs. Based on a variety of experimental evidence, including recent structural data, there is now clear evidence indicating that at least some α7-selective PAMs bind to an inter-subunit site located in the transmembrane domain. In contrast, there are differing hypotheses about the site or sites at which allosteric agonists bind to α7 nAChRs. It will be argued that the available evidence supports the conclusion that direct allosteric activation by allosteric agonists/ago-PAMs occurs via the same inter-subunit transmembrane site that has been identified for several α7-selective PAMs.
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Affiliation(s)
- Victoria R Sanders
- Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Neil S Millar
- Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.
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40
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Bondarenko V, Chen Q, Singewald K, Haloi N, Tillman TS, Howard RJ, Lindahl E, Xu Y, Tang P. Structural Elucidation of Ivermectin Binding to α7nAChR and the Induced Channel Desensitization. ACS Chem Neurosci 2023; 14:1156-1165. [PMID: 36821490 PMCID: PMC10020961 DOI: 10.1021/acschemneuro.2c00783] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
The α7 nicotinic acetylcholine receptor (α7nAChR) mediates signaling in the central nervous system and cholinergic anti-inflammatory pathways. Ivermectin is a positive allosteric modulator of a full-length α7nAChR and an agonist of the α7nAChR construct containing transmembrane (TMD) and intracellular (ICD) domains, but structural insights of the binding have not previously been determined. Here, combining nuclear magnetic resonance as a primary experimental tool with Rosetta comparative modeling and molecular dynamics simulations, we have revealed details of ivermectin binding to the α7nAChR TMD + ICD and corresponding structural changes in an ivermectin-induced desensitized state. Ivermectin binding was stabilized predominantly by hydrophobic interactions from interfacial residues between adjacent subunits near the extracellular end of the TMD, where the inter-subunit gap was substantially expanded in comparison to the apo structure. The ion-permeation pathway showed a profile distinctly different from the resting-state profile but similar to profiles of desensitized α7nAChR. The ICD also exhibited structural changes, including reorientation of the MX and h3 helices relative to the channel axis. The resulting structures of the α7nAChR TMD + ICD in complex with ivermectin provide opportunities for discovering new modulators of therapeutic potential and exploring the structural basis of cytoplasmic signaling under different α7nAChR functional states.
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Affiliation(s)
- Vasyl Bondarenko
- Department
of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Qiang Chen
- Department
of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Kevin Singewald
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Nandan Haloi
- Department
of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, PO Box 1031, SE-17121 Solna, Sweden
- Department
of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, PO Box 1031, SE-17121 Solna, Sweden
| | - Tommy S. Tillman
- Department
of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Rebecca J. Howard
- Department
of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, PO Box 1031, SE-17121 Solna, Sweden
- Department
of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, PO Box 1031, SE-17121 Solna, Sweden
| | - Erik Lindahl
- Department
of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, PO Box 1031, SE-17121 Solna, Sweden
- Department
of Applied Physics, Swedish e-Science Research Center, KTH Royal Institute of Technology, PO Box 1031, SE-17121 Solna, Sweden
| | - Yan Xu
- Department
of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Pharmacology and Chemical Biology, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Physics and Astronomy, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Pei Tang
- Department
of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Pharmacology and Chemical Biology, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Department
of Computational and Systems Biology, University
of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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41
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Barrantes FJ. Structure and function meet at the nicotinic acetylcholine receptor-lipid interface. Pharmacol Res 2023; 190:106729. [PMID: 36931540 DOI: 10.1016/j.phrs.2023.106729] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023]
Abstract
The nicotinic acetylcholine receptor (nAChR) is a transmembrane protein that mediates fast intercellular communication in response to the endogenous neurotransmitter acetylcholine. It is the best characterized and archetypal molecule in the superfamily of pentameric ligand-gated ion channels (pLGICs). As a typical transmembrane macromolecule, it interacts extensively with its vicinal lipid microenvironment. Experimental evidence provides a wealth of information on receptor-lipid crosstalk: the nAChR exerts influence on its immediate membrane environment and conversely, the lipid moiety modulates ligand binding, affinity state transitions and gating of ion translocation functions of the receptor protein. Recent cryogenic electron microscopy (cryo-EM) studies have unveiled the occurrence of sites for phospholipids and cholesterol on the lipid-exposed regions of neuronal and electroplax nAChRs, confirming early spectroscopic and affinity labeling studies demonstrating the close contact of lipid molecules with the receptor transmembrane segments. This new data provides structural support to the postulated "lipid sensor" ability displayed by the outer ring of M4 transmembrane domains and their modulatory role on nAChR function, as we postulated a decade ago. Borrowing from the best characterized nAChR, the electroplax (muscle-type) receptor, and exploiting new structural information on the neuronal nAChR, it is now possible to achieve an improved depiction of these sites. In combination with site-directed mutagenesis, single-channel electrophysiology, and molecular dynamics studies, the new structural information delivers a more comprehensive portrayal of these lipid-sensitive loci, providing mechanistic explanations for their ability to modulate nAChR properties and raising the possibility of targetting them in disease.
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Affiliation(s)
- Francisco J Barrantes
- Laboratory of Molecular Neurobiology, Biomedical Research Institute, Faculty of Medical Sciences, Pontifical Catholic University of Argentina (UCA) - Argentine Scientific & Technol. Research Council (CONICET), Av. Alicia Moreau de Justo 1600, C1107AAZ Buenos Aires, Argentina.
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42
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Chrestia JF, Turani O, Araujo NR, Hernando G, Esandi MDC, Bouzat C. Regulation of nicotinic acetylcholine receptors by post-translational modifications. Pharmacol Res 2023; 190:106712. [PMID: 36863428 DOI: 10.1016/j.phrs.2023.106712] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/21/2023] [Accepted: 02/24/2023] [Indexed: 03/04/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) comprise a family of pentameric ligand-gated ion channels widely distributed in the central and peripheric nervous system and in non-neuronal cells. nAChRs are involved in chemical synapses and are key actors in vital physiological processes throughout the animal kingdom. They mediate skeletal muscle contraction, autonomic responses, contribute to cognitive processes, and regulate behaviors. Dysregulation of nAChRs is associated with neurological, neurodegenerative, inflammatory and motor disorders. In spite of the great advances in the elucidation of nAChR structure and function, our knowledge about the impact of post-translational modifications (PTMs) on nAChR functional activity and cholinergic signaling has lagged behind. PTMs occur at different steps of protein life cycle, modulating in time and space protein folding, localization, function, and protein-protein interactions, and allow fine-tuned responses to changes in the environment. A large body of evidence demonstrates that PTMs regulate all levels of nAChR life cycle, with key roles in receptor expression, membrane stability and function. However, our knowledge is still limited, restricted to a few PTMs, and many important aspects remain largely unknown. There is thus a long way to go to decipher the association of aberrant PTMs with disorders of cholinergic signaling and to target PTM regulation for novel therapeutic interventions. In this review we provide a comprehensive overview of what is known about how different PTMs regulate nAChR.
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Affiliation(s)
- Juan Facundo Chrestia
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina
| | - Ornella Turani
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina
| | - Noelia Rodriguez Araujo
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina
| | - Guillermina Hernando
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina
| | - María Del Carmen Esandi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina
| | - Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina.
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43
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Zhu X, Wang S, Kaas Q, Yu J, Wu Y, Harvey PJ, Zhangsun D, Craik DJ, Luo S. Discovery, Characterization, and Engineering of LvIC, an α4/4-Conotoxin That Selectively Blocks Rat α6/α3β4 Nicotinic Acetylcholine Receptors. J Med Chem 2023; 66:2020-2031. [PMID: 36682014 DOI: 10.1021/acs.jmedchem.2c01786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
α6β4 nicotinic acetylcholine receptors (nAChRs) are expressed in the central and peripheral nervous systems, but their functions are not fully understood, largely because of a lack of specific ligands. Here, we characterized a novel α-conotoxin, LvIC, and designed a series of analogues to probe structure-activity relationships at the α6β4 nAChR. The potency and selectivity of these conotoxins were tested using two-electrode voltage-clamp recording on nAChR subtypes expressed in Xenopus laevis oocytes. One of the analogues, [D1G,ΔQ14]LvIC, potently blocked α6/α3β4 nAChRs (α6/α3 is a chimera) with an IC50 of 19 nM, with minimal activity at other nAChR subtypes, including the structurally similar α6/α3β2β3 and α3β4 subtypes. Using NMR, molecular docking, and receptor mutation, structure-activity relationships of [D1G,ΔQ14]LvIC at the α6/α3β4 nAChR were defined. It is a potent and specific antagonist of α6β4 nAChRs that could potentially serve as a novel molecular probe to explore α6β4 nAChR-related neurophysiological and pharmacological functions.
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Affiliation(s)
- Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Shuai Wang
- Center for Novel Target and Therapeutic Intervention, Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Jinpeng Yu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Yong Wu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Dongting Zhangsun
- School of Medicine, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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44
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Straub CJ, Rusali LE, Kremiller KM, Riley AP. What We Have Gained from Ibogaine: α3β4 Nicotinic Acetylcholine Receptor Inhibitors as Treatments for Substance Use Disorders. J Med Chem 2023; 66:107-121. [PMID: 36440853 PMCID: PMC10034762 DOI: 10.1021/acs.jmedchem.2c01562] [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] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For decades, ibogaine─the main psychoactive alkaloid found in Tabernanthe iboga─has been investigated as a possible treatment for substance use disorders (SUDs) due to its purported ability to interrupt the addictive properties of multiple drugs of abuse. Of the numerous pharmacological actions of ibogaine and its derivatives, the inhibition of α3β4 nicotinic acetylcholine receptors (nAChRs), represents a probable mechanism of action for their apparent anti-addictive activity. In this Perspective, we examine several classes of compounds that have been discovered and developed to target α3β4 nAChRs. Specifically, by focusing on compounds that have proven efficacious in pre-clinical models of drug abuse and have been evaluated clinically, we highlight the promising potential of the α3β4 nAChRs as viable targets to treat a wide array of SUDs. Additionally, we discuss the challenges faced by the existing classes of α3β4 nAChR ligands that must be overcome to develop them into therapeutic treatments.
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Affiliation(s)
- Carolyn J Straub
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Lisa E Rusali
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Kyle M Kremiller
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
| | - Andrew P Riley
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 60612, United States
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45
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Aso K, Kono M, Abe N, Fujieda Y, Kato M, Atsumi T. Anti-ganglionic nicotinic acetylcholine receptor α3 subunit antibody as a potential biomarker associated with lupus enteritis. Mod Rheumatol 2023; 33:154-159. [PMID: 35107135 DOI: 10.1093/mr/roac006] [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: 11/17/2021] [Revised: 12/20/2021] [Accepted: 12/25/2021] [Indexed: 01/05/2023]
Abstract
OBJECTIVES We aimed to identify the clinical significance of anti-ganglionic nicotinic acetylcholine receptor α3 subunit (gAChRα3) antibodies (Abs) in patients with systemic lupus erythematosus (SLE). METHODS This retrospective study comprised adult patients with SLE who visited our hospital from 2006 through 2019. Anti-gAChRα3 Abs were measured in the sera of patients with SLE using a luciferase immunoprecipitation system assay. The clinical features of the patients with or without anti-gAChRα3 Abs were compared. We evaluated whether the Abs predict a specific manifestation and affect its development or relapse rate. RESULTS Among 144 patients, anti-gAChRα3 Abs were detected in 29 patients. Lupus enteritis (LE) was more frequently seen in anti-gAChRα3 Ab-positive patients than negative patients. The levels of anti-gAChRα3 Abs were significantly higher in patients with LE than those with other lupus manifestations. Logistic regression analysis revealed the anti-gAChRα3 Abs were independent predictors for LE (odds ratio 6.2, 95% confidence interval 1.9-20.3, p = .002). Kaplan-Meier analysis showed the rate of LE development or relapse from the time of sera collection was higher in anti-gAChRα3 Ab-positive patients than in negative patients (p < .001). CONCLUSION Anti-gAChRα3 Abs could be a predictive biomarker for the development or relapse of LE.
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Affiliation(s)
- Kuniyuki Aso
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaidô, Japan
| | - Michihito Kono
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaidô, Japan
| | - Nobuya Abe
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaidô, Japan
| | - Yuichiro Fujieda
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaidô, Japan
| | - Masaru Kato
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaidô, Japan
| | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaidô, Japan
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46
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Li RQ, Zhao XH, Zhu Q, Liu T, Hondermarck H, Thorne RF, Zhang XD, Gao JN. Exploring neurotransmitters and their receptors for breast cancer prevention and treatment. Theranostics 2023; 13:1109-1129. [PMID: 36793869 PMCID: PMC9925324 DOI: 10.7150/thno.81403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/18/2023] [Indexed: 02/04/2023] Open
Abstract
While psychological factors have long been linked to breast cancer pathogenesis and outcomes, accumulating evidence is revealing how the nervous system contributes to breast cancer development, progression, and treatment resistance. Central to the psychological-neurological nexus are interactions between neurotransmitters and their receptors expressed on breast cancer cells and other types of cells in the tumor microenvironment, which activate various intracellular signaling pathways. Importantly, the manipulation of these interactions is emerging as a potential avenue for breast cancer prevention and treatment. However, an important caveat is that the same neurotransmitter can exert multiple and sometimes opposing effects. In addition, certain neurotransmitters can be produced and secreted by non-neuronal cells including breast cancer cells that similarly activate intracellular signaling upon binding to their receptors. In this review we dissect the evidence for the emerging paradigm linking neurotransmitters and their receptors with breast cancer. Foremost, we explore the intricacies of such neurotransmitter-receptor interactions, including those that impinge on other cellular components of the tumor microenvironment, such as endothelial cells and immune cells. Moreover, we discuss findings where clinical agents used to treat neurological and/or psychological disorders have exhibited preventive/therapeutic effects against breast cancer in either associative or pre-clinical studies. Further, we elaborate on the current progress to identify druggable components of the psychological-neurological nexus that can be exploited for the prevention and treatment of breast cancer as well as other tumor types. We also provide our perspectives regarding future challenges in this field where multidisciplinary cooperation is a paramount requirement.
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Affiliation(s)
- Ruo Qi Li
- General Surgery Department, Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Taiyuan, Shanxi, China.,These authors contributed equally to this work
| | - Xiao Hong Zhao
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, New South Wales, Australia.,These authors contributed equally to this work
| | - Qin Zhu
- General Surgery Department, Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Taiyuan, Shanxi, China
| | - Tao Liu
- Children's Cancer Institute Australia for Medical Research, The University of New South Wales, Sydney, NSW, Australia
| | - Hubert Hondermarck
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, New South Wales, Australia
| | - Rick F Thorne
- Translational Research Institute, Henan Provincial and Zhengzhou City Key laboratory of Non-coding RNA and Cancer Metabolism, Henan International Joint Laboratory of Non-coding RNA and Metabolism in Cancer, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Academy of Medical Sciences, Zhengzhou University, Henan, China
| | - Xu Dong Zhang
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, New South Wales, Australia.,Translational Research Institute, Henan Provincial and Zhengzhou City Key laboratory of Non-coding RNA and Cancer Metabolism, Henan International Joint Laboratory of Non-coding RNA and Metabolism in Cancer, Zhengzhou University People's Hospital and Henan Provincial People's Hospital, Academy of Medical Sciences, Zhengzhou University, Henan, China
| | - Jin Nan Gao
- General Surgery Department, Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Taiyuan, Shanxi, China
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47
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Biophysical characterization of calcium-binding and modulatory-domain dynamics in a pentameric ligand-gated ion channel. Proc Natl Acad Sci U S A 2022; 119:e2210669119. [PMID: 36480474 PMCID: PMC9897478 DOI: 10.1073/pnas.2210669119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pentameric ligand-gated ion channels (pLGICs) perform electrochemical signal transduction in organisms ranging from bacteria to humans. Among the prokaryotic pLGICs, there is architectural diversity involving N-terminal domains (NTDs) not found in eukaryotic relatives, exemplified by the calcium-sensitive channel (DeCLIC) from a Desulfofustis deltaproteobacterium, which has an NTD in addition to the canonical pLGIC structure. Here, we have characterized the structure and dynamics of DeCLIC through cryoelectron microscopy (cryo-EM), small-angle neutron scattering (SANS), and molecular dynamics (MD) simulations. In the presence and absence of calcium, cryo-EM yielded structures with alternative conformations of the calcium-binding site. SANS profiles further revealed conformational diversity at room temperature beyond that observed in static structures, shown through MD to be largely attributable to rigid-body motions of the NTD relative to the protein core, with expanded and asymmetric conformations improving the fit of the SANS data. This work reveals the range of motion available to the DeCLIC NTD and calcium-binding site, expanding the conformational landscape of the pLGIC family. Further, these findings demonstrate the power of combining low-resolution scattering, high-resolution structural, and MD simulation data to elucidate interfacial interactions that are highly conserved in the pLGIC family.
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48
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Semenets AP, Suleiman MM, Fedosov AI, Shtrygol SY, Havrylov IO, Mishchenko MV, Kovalenko SM, Georgiyants VA, Perekhoda LO. Synthesis, docking, and biological evaluation of novel 1-benzyl-4-(4-(R)-5-sulfonylidene-4,5-dihydro-1H-1,2,4-triazol-3-yl)pyrrolidin-2-ones as potential nootropic agents. Eur J Med Chem 2022; 244:114823. [DOI: 10.1016/j.ejmech.2022.114823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/14/2022] [Accepted: 10/01/2022] [Indexed: 11/28/2022]
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49
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Slobodyanyuk M, Banda-Vázquez JA, Thompson MJ, Dean RA, Baenziger JE, Chica RA, daCosta CJB. Origin of acetylcholine antagonism in ELIC, a bacterial pentameric ligand-gated ion channel. Commun Biol 2022; 5:1264. [PMID: 36400839 PMCID: PMC9674596 DOI: 10.1038/s42003-022-04227-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 11/04/2022] [Indexed: 11/20/2022] Open
Abstract
ELIC is a prokaryotic homopentameric ligand-gated ion channel that is homologous to vertebrate nicotinic acetylcholine receptors. Acetylcholine binds to ELIC but fails to activate it, despite bringing about conformational changes indicative of activation. Instead, acetylcholine competitively inhibits agonist-activated ELIC currents. What makes acetylcholine an agonist in an acetylcholine receptor context, and an antagonist in an ELIC context, is not known. Here we use available structures and statistical coupling analysis to identify residues in the ELIC agonist-binding site that contribute to agonism. Substitution of these ELIC residues for their acetylcholine receptor counterparts does not convert acetylcholine into an ELIC agonist, but in some cases reduces the sensitivity of ELIC to acetylcholine antagonism. Acetylcholine antagonism can be abolished by combining two substitutions that together appear to knock out acetylcholine binding. Thus, making the ELIC agonist-binding site more acetylcholine receptor-like, paradoxically reduces the apparent affinity for acetylcholine, demonstrating that residues important for agonist binding in one context can be deleterious in another. These findings reinforce the notion that although agonism originates from local interactions within the agonist-binding site, it is a global property with cryptic contributions from distant residues. Finally, our results highlight an underappreciated mechanism of antagonism, where agonists with appreciable affinity, but negligible efficacy, present as competitive antagonists. A structural and functional study of the prokaryotic ligand-gated ion channel, ELIC, provides insight into the origin of agonism and antagonism at nicotinic acetylcholine receptors.
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50
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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] [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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