1
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Dong J, Zhang P, Xie J, Xie T, Zhu X, Zhangsun D, Yu J, Luo S. Loop2 Size Modification Reveals Significant Impacts on the Potency of α-Conotoxin TxID. Mar Drugs 2023; 21:md21050286. [PMID: 37233480 DOI: 10.3390/md21050286] [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: 04/05/2023] [Revised: 04/27/2023] [Accepted: 04/29/2023] [Indexed: 05/27/2023] Open
Abstract
α4/6-conotoxin TxID, which was identified from Conus textile, simultaneously blocks rat (r) α3β4 and rα6/α3β4 nicotinic acetylcholine receptors (nAChRs) with IC50 values of 3.6 nM and 33.9 nM, respectively. In order to identify the effects of loop2 size on the potency of TxID, alanine (Ala) insertion and truncation mutants were designed and synthesized in this study. An electrophysiological assay was used to evaluate the activity of TxID and its loop2-modified mutants. The results showed that the inhibition of 4/7-subfamily mutants [+9A]TxID, [+10A]TxID, [+14A]TxID, and all the 4/5-subfamily mutants against rα3β4 and rα6/α3β4 nAChRs decreased. Overall, ala-insertion or truncation of the 9th, 10th, and 11th amino acid results in a loss of inhibition and the truncation of loop2 has more obvious impacts on its functions. Our findings have strengthened the understanding of α-conotoxin, provided guidance for further modifications, and offered a perspective for future studies on the molecular mechanism of the interaction between α-conotoxins and nAChRs.
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Affiliation(s)
- Jianying Dong
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Panpan Zhang
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Junjie Xie
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Ting Xie
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Xiaopeng Zhu
- 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
| | - 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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2
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Groome JR. Historical Perspective of the Characterization of Conotoxins Targeting Voltage-Gated Sodium Channels. Mar Drugs 2023; 21:md21040209. [PMID: 37103349 PMCID: PMC10142487 DOI: 10.3390/md21040209] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Marine toxins have potent actions on diverse sodium ion channels regulated by transmembrane voltage (voltage-gated ion channels) or by neurotransmitters (nicotinic acetylcholine receptor channels). Studies of these toxins have focused on varied aspects of venom peptides ranging from evolutionary relationships of predator and prey, biological actions on excitable tissues, potential application as pharmacological intervention in disease therapy, and as part of multiple experimental approaches towards an understanding of the atomistic characterization of ion channel structure. This review examines the historical perspective of the study of conotoxin peptides active on sodium channels gated by transmembrane voltage, which has led to recent advances in ion channel research made possible with the exploitation of the diversity of these marine toxins.
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Affiliation(s)
- James R Groome
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, USA
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3
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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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4
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Ho TNT, Abraham N, Lewis RJ. Structure-Function of Neuronal Nicotinic Acetylcholine Receptor Inhibitors Derived From Natural Toxins. Front Neurosci 2020; 14:609005. [PMID: 33324158 PMCID: PMC7723979 DOI: 10.3389/fnins.2020.609005] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 10/30/2020] [Indexed: 12/19/2022] Open
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are prototypical cation-selective, ligand-gated ion channels that mediate fast neurotransmission in the central and peripheral nervous systems. nAChRs are involved in a range of physiological and pathological functions and hence are important therapeutic targets. Their subunit homology and diverse pentameric assembly contribute to their challenging pharmacology and limit their drug development potential. Toxins produced by an extensive range of algae, plants and animals target nAChRs, with many proving pivotal in elucidating receptor pharmacology and biochemistry, as well as providing templates for structure-based drug design. The crystal structures of these toxins with diverse chemical profiles in complex with acetylcholine binding protein (AChBP), a soluble homolog of the extracellular ligand-binding domain of the nAChRs and more recently the extracellular domain of human α9 nAChRs, have been reported. These studies have shed light on the diverse molecular mechanisms of ligand-binding at neuronal nAChR subtypes and uncovered critical insights useful for rational drug design. This review provides a comprehensive overview and perspectives obtained from structure and function studies of diverse plant and animal toxins and their associated inhibitory mechanisms at neuronal nAChRs.
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Affiliation(s)
| | | | - Richard J. Lewis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
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5
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Giribaldi J, Ragnarsson L, Pujante T, Enjalbal C, Wilson D, Daly NL, Lewis RJ, Dutertre S. Synthesis, Pharmacological and Structural Characterization of Novel Conopressins from Conus miliaris. Mar Drugs 2020; 18:E150. [PMID: 32155768 PMCID: PMC7143535 DOI: 10.3390/md18030150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 12/21/2022] Open
Abstract
Cone snails produce a fast-acting and often paralyzing venom, largely dominated by disulfide-rich conotoxins targeting ion channels. Although disulfide-poor conopeptides are usually minor components of cone snail venoms, their ability to target key membrane receptors such as GPCRs make them highly valuable as drug lead compounds. From the venom gland transcriptome of Conus miliaris, we report here on the discovery and characterization of two conopressins, which are nonapeptide ligands of the vasopressin/oxytocin receptor family. These novel sequence variants show unusual features, including a charge inversion at the critical position 8, with an aspartate instead of a highly conserved lysine or arginine residue. Both the amidated and acid C-terminal analogues were synthesized, followed by pharmacological characterization on human and zebrafish receptors and structural investigation by NMR. Whereas conopressin-M1 showed weak and only partial agonist activity at hV1bR (amidated form only) and ZFV1a1R (both amidated and acid form), both conopressin-M2 analogues acted as full agonists at the ZFV2 receptor with low micromolar affinity. Together with the NMR structures of amidated conopressins-M1, -M2 and -G, this study provides novel structure-activity relationship information that may help in the design of more selective ligands.
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Affiliation(s)
- Julien Giribaldi
- Institut des Biomolécules Max Mousseron, UMR 5247, Université de Montpellier-CNRS, 34095 Montpellier, France; (J.G.); (T.P.); (C.E.)
| | - Lotten Ragnarsson
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia; (L.R.); (R.J.L.)
| | - Tom Pujante
- Institut des Biomolécules Max Mousseron, UMR 5247, Université de Montpellier-CNRS, 34095 Montpellier, France; (J.G.); (T.P.); (C.E.)
| | - Christine Enjalbal
- Institut des Biomolécules Max Mousseron, UMR 5247, Université de Montpellier-CNRS, 34095 Montpellier, France; (J.G.); (T.P.); (C.E.)
| | - David Wilson
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia; (D.W.); (N.L.D.)
| | - Norelle L. Daly
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia; (D.W.); (N.L.D.)
| | - Richard J. Lewis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia; (L.R.); (R.J.L.)
| | - Sebastien Dutertre
- Institut des Biomolécules Max Mousseron, UMR 5247, Université de Montpellier-CNRS, 34095 Montpellier, France; (J.G.); (T.P.); (C.E.)
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6
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Phasic Dopamine Release Magnitude Tracks Individual Differences in Sensitization of Locomotor Response following a History of Nicotine Exposure. Sci Rep 2020; 10:173. [PMID: 31932634 PMCID: PMC6957501 DOI: 10.1038/s41598-019-56884-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 12/06/2019] [Indexed: 02/04/2023] Open
Abstract
Smoking remains the primary cause of preventable death in the United States and smoking related illness costs more than $300 billion annually. Nicotine (the primary reinforcer in cigarettes) causes changes in behavior and neurochemistry that lead to increased probability of relapse. Given the role of mesolimbic dopamine projections in motivation, substance use disorder, and drug relapse, we examined the effect of repeated nicotine on rapid dopamine signals in the nucleus accumbens (NAc) of rats. Adult, male Sprague-Dawley rats were exposed to nicotine (0.2 or 0.4 mg/kg, subcutaneous) once daily for 7 days. On day 8, dopamine release and uptake dynamics, and their modulation by nicotinic receptor agonists and antagonists, were assessed using fast scan cyclic voltammetry in the NAc core. Nicotine exposure decreased electrically-stimulated dopamine release across a range of stimulation frequencies and decreased α6β2-containing nicotinic receptor control over dopamine release. Additionally, nicotine locomotor sensitization correlated with accumbal dopamine modulation by nicotine and mecamylamine. Taken together, our study suggests that repeated exposure to nicotine blunts dopamine release in the NAc core through changes in α6β2 modulation of dopamine release and individual differences in the sensitivity to this outcome may predict variation in behavioral models of vulnerability to substance use disorder.
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7
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Ning J, Ren J, Xiong Y, Wu Y, Zhangsun M, Zhangsun D, Zhu X, Luo S. Identification of Crucial Residues in α-Conotoxin EI Inhibiting Muscle Nicotinic Acetylcholine Receptor. Toxins (Basel) 2019; 11:toxins11100603. [PMID: 31623211 PMCID: PMC6832962 DOI: 10.3390/toxins11100603] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 09/30/2019] [Accepted: 10/08/2019] [Indexed: 12/31/2022] Open
Abstract
α-Conotoxins (α-CTxs) are small disulfide-rich peptides from venom of Conus species that target nicotinic acetylcholine receptors (nAChRs). The muscle-type nAChRs have been recognized as a potential target for several diseases, such as myogenic disorders, muscle dystrophies, and myasthenia gravis. EI, an α4/7-CTx, mainly blocks α1β1δε nAChRs and has an extra N-terminal extension of three amino acids. In this study, the alanine scanning (Ala-scan) mutagenesis was applied in order to identify key residues of EI for binding with mouse α1β1δε nAChR. The Ala-substituted analogues were tested for their abilities of modulating muscle and neuronal nAChRs in Xenopus laevis oocytes using two-electrode voltage clamp (TEVC) recordings. Electrophysiological results indicated that the vital residues for functional activity of EI were His-7, Pro-8, Met-12, and Pro-15. These changes exhibited a significant decrease in potency of EI against mouse α1β1δε nAChR. Interestingly, replacing the critical serine (Ser) at position 13 with an alanine (Ala) residue resulted in a 2-fold increase in potency at the α1β1δε nAChR, and showed loss of activity on α3β2 and α3β4 nAChRs. Selectivity and potency of [S13A] EI was improved compared with wild-type EI (WT EI). In addition, the structure–activity relationship (SAR) of EI revealed that the “Arg1–Asn2–Hyp3” residues at the N-terminus conferred potency at the muscle-type nAChRs, and the deletion analogue △1–3 EI caused a total loss of activity at the α1β1δε nAChR. Circular dichroism (CD) spectroscopy studies demonstrated that activity loss of truncated analogue △1–3 EI for α1β1δε nAChR is attributed to disturbance of the secondary structure. In this report, an Ala-scan mutagenesis strategy is presented to identify crucial residues that are significantly affecting potency of E1 for mouse α1β1δε nAChR. It may also be important in remodeling of some novel ligands for inhibiting muscle-type nAChRs.
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Affiliation(s)
- Jiong Ning
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Jie Ren
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Yang Xiong
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Yong Wu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Manqi Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Xiaopeng Zhu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.
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8
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Conformational dynamics of [Formula: see text]-conotoxin PnIB in complex solvent systems. Mol Divers 2019; 24:1291-1299. [PMID: 31502188 DOI: 10.1007/s11030-019-09993-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/03/2019] [Indexed: 01/13/2023]
Abstract
Cone snails are slow-moving animals that secure survival by injecting to their prey a concoction of highly potent and stable neurotoxic peptides called conotoxins. These small toxins (~ 10-30 AA) interact with ion channels and their diverse structures account for various variables such as the environment and the prey of preference. This study probed the conformational space of α-conotoxin PnIB from Conus pennaceus by performing all-atom molecular dynamics simulations on the conotoxin in complex solvent systems of water and octanol. Secondary structure analyses showed a uniform conformation for the pure (C100Oc, C100W) and minute (C95Oc, C5Oc) systems. In C50Oc, however, structural changes were observed. The original helices were converted to turns and were shown to happen simultaneously with the elongation of the helix and shortening of end-to-end distance. The transitions complement the orientation of the peptide at the interface. The shift to the broken helix conformation is marked by the rearrangement of solvent molecules to a framework that favors the accumulation of water molecules at residues 6-11 of the H2 region. This promotes specific protein-solvent interactions that facilitate secondary structure transitions. As PnIB has shown favorable binding toward neuronal nicotinic acetylcholine receptors, this study may provide insights on this conotoxin's therapeutic potential. Description: Structural changes in PnIB are accompanied by a simultaneous change in solvent density.
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9
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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10
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Zouridakis M, Papakyriakou A, Ivanov IA, Kasheverov IE, Tsetlin V, Tzartos S, Giastas P. Crystal Structure of the Monomeric Extracellular Domain of α9 Nicotinic Receptor Subunit in Complex With α-Conotoxin RgIA: Molecular Dynamics Insights Into RgIA Binding to α9α10 Nicotinic Receptors. Front Pharmacol 2019; 10:474. [PMID: 31118896 PMCID: PMC6504684 DOI: 10.3389/fphar.2019.00474] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 04/15/2019] [Indexed: 12/20/2022] Open
Abstract
The α9 subunit of nicotinic acetylcholine receptors (nAChRs) exists mainly in heteropentameric assemblies with α10. Accumulating data indicate the presence of three different binding sites in α9α10 nAChRs: the α9(+)/α9(−), the α9(+)/α10(−), and the α10(+)/α9(−). The major role of the principal (+) side of the extracellular domain (ECD) of α9 subunit in binding of the antagonists methyllylcaconitine and α-bungarotoxin was shown previously by the crystal structures of the monomeric α9-ECD with these molecules. Here we present the 2.26-Å resolution crystal structure of α9-ECD in complex with α-conotoxin (α-Ctx) RgIA, a potential drug for chronic pain, the first structure reported for a complex between an nAChR domain and an α-Ctx. Superposition of this structure with those of other α-Ctxs bound to the homologous pentameric acetylcholine binding proteins revealed significant similarities in the orientation of bound conotoxins, despite the monomeric state of the α9-ECD. In addition, ligand-binding studies calculated a binding affinity of RgIA to the α9-ECD at the low micromolar range. Given the high identity between α9 and α10 ECDs, particularly at their (+) sides, the presented structure was used as template for molecular dynamics simulations of the ECDs of the human α9α10 nAChR in pentameric assemblies. Our results support a favorable binding of RgIA at α9(+)/α9(−) or α10(+)/α9(−) rather than the α9(+)/α10(−) interface, in accordance with previous mutational and functional data.
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Affiliation(s)
- Marios Zouridakis
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | | | - Igor A Ivanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Victor Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,PhysBio of MEPhI, Moscow, Russia
| | - Socrates Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece.,Department of Pharmacy, University of Patras, Patras, Greece
| | - Petros Giastas
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
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11
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Rationally Designed α-Conotoxin Analogues Maintained Analgesia Activity and Weakened Side Effects. Molecules 2019; 24:molecules24020337. [PMID: 30669328 PMCID: PMC6358911 DOI: 10.3390/molecules24020337] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/05/2019] [Accepted: 01/17/2019] [Indexed: 11/16/2022] Open
Abstract
A lack of specificity is restricting the further application of conotoxin from Conus bullatus (BuIA). In this study, an analogue library of BuIA was established and virtual screening was used, which identified high α7 nicotinic acetylcholine receptor (nAChR)-selectivity analogues. The analogues were synthesized and tested for their affinity to functional human α7 nAChR and for the regulation of intracellular calcium ion capacity in neurons. Immunofluorescence, flow cytometry, and patch clamp results showed that the analogues maintained their capacity for calcium regulation. The results of the hot-plate model and paclitaxel-induced peripheral neuropathy model indicated that, when compared with natural BuIA, the analgesia activities of the analogues in different models were maintained. To analyze the adverse effects and toxicity of BuIA and its analogues, the tail suspension test, forced swimming test, and open field test were used. The results showed that the safety and toxicity of the analogues were significantly better than BuIA. The analogues of BuIA with an appropriate and rational mutation showed high selectivity and maintained the regulation of Ca2+ capacity in neurons and activities of analgesia, whereas the analogues demonstrated that the adverse effects of natural α-conotoxins could be reduced.
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12
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Kondasinghe TD, Saraha HY, Jackowski ST, Stockdill JL. Raising the Bar On-Bead: Efficient On-Resin Synthesis of α-Conotoxin LvIA. Tetrahedron Lett 2019; 60:23-28. [PMID: 31564757 PMCID: PMC6764457 DOI: 10.1016/j.tetlet.2018.11.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
α4/7-Conotoxin LvIA is an isoform-selective inhibitor of the α3β2 nicotinic acetylcholine receptor. An efficient strategy for the synthesis of this toxin is critical to advancing its utility as a probe for receptor function and as a potential pharmaceutical lead target. On-resin methods for peptide synthesis offer potential synthetic advantages; however, strategies for on-resin formation of multiple disulfides have historically been low-yielding. Here, we harness the reactivity of the Allocam protecting group and employ 3-amino acid spacer strategy to synthesize α4/7-conotoxin LvIA via three different on-resin strategies, each of which results in an isolated yield higher than prior fully on-resin approaches.
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Affiliation(s)
| | - Hasina Y. Saraha
- Department of Chemistry, Wayne State University, Detroit, MI 48202
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13
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Abraham N, Lewis RJ. Neuronal Nicotinic Acetylcholine Receptor Modulators from Cone Snails. Mar Drugs 2018; 16:E208. [PMID: 29899286 PMCID: PMC6024932 DOI: 10.3390/md16060208] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/25/2018] [Accepted: 06/06/2018] [Indexed: 12/15/2022] Open
Abstract
Marine cone snails are a large family of gastropods that have evolved highly potent venoms for predation and defense. The cone snail venom has exceptional molecular diversity in neuropharmacologically active compounds, targeting a range of receptors, ion channels, and transporters. These conotoxins have helped to dissect the structure and function of many of these therapeutically significant targets in the central and peripheral nervous systems, as well as unravelling the complex cellular mechanisms modulated by these receptors and ion channels. This review provides an overview of α-conotoxins targeting neuronal nicotinic acetylcholine receptors. The structure and activity of both classical and non-classical α-conotoxins are discussed, along with their contributions towards understanding nicotinic acetylcholine receptor (nAChR) structure and function.
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Affiliation(s)
- Nikita Abraham
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Richard J Lewis
- IMB Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
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14
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Gao B, Peng C, Yang J, Yi Y, Zhang J, Shi Q. Cone Snails: A Big Store of Conotoxins for Novel Drug Discovery. Toxins (Basel) 2017; 9:E397. [PMID: 29215605 PMCID: PMC5744117 DOI: 10.3390/toxins9120397] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/11/2022] Open
Abstract
Marine drugs have developed rapidly in recent decades. Cone snails, a group of more than 700 species, have always been one of the focuses for new drug discovery. These venomous snails capture prey using a diverse array of unique bioactive neurotoxins, usually named as conotoxins or conopeptides. These conotoxins have proven to be valuable pharmacological probes and potential drugs due to their high specificity and affinity to ion channels, receptors, and transporters in the nervous systems of target prey and humans. Several research groups, including ours, have examined the venom gland of cone snails using a combination of transcriptomic and proteomic sequencing, and revealed the existence of hundreds of conotoxin transcripts and thousands of conopeptides in each Conus species. Over 2000 nucleotide and 8000 peptide sequences of conotoxins have been published, and the number is still increasing quickly. However, more than 98% of these sequences still lack 3D structural and functional information. With the rapid development of genomics and bioinformatics in recent years, functional predictions and investigations on conotoxins are making great progress in promoting the discovery of novel drugs. For example, ω-MVIIA was approved by the U.S. Food and Drug Administration in 2004 to treat chronic pain, and nine more conotoxins are at various stages of preclinical or clinical evaluation. In short, the genus Conus, the big family of cone snails, has become an important genetic resource for conotoxin identification and drug development.
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Affiliation(s)
- Bingmiao Gao
- Hainan Provincial Key Laboratory of Research and Development of Tropical Medicinal Plants, Hainan Medical University, Haikou 571199, China.
| | - Chao Peng
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
| | - Jiaan Yang
- Micro Pharmtech, Ltd., Wuhan 430075, China.
| | - Yunhai Yi
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China.
| | - Junqing Zhang
- Hainan Provincial Key Laboratory of Research and Development of Tropical Medicinal Plants, Hainan Medical University, Haikou 571199, China.
| | - Qiong Shi
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China.
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15
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Dutertre S, Nicke A, Tsetlin VI. Nicotinic acetylcholine receptor inhibitors derived from snake and snail venoms. Neuropharmacology 2017. [PMID: 28623170 DOI: 10.1016/j.neuropharm.2017.06.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nicotinic acetylcholine receptor (nAChR) represents the prototype of ligand-gated ion channels. It is vital for neuromuscular transmission and an important regulator of neurotransmission. A variety of toxic compounds derived from diverse species target this receptor and have been of elemental importance in basic and applied research. They enabled milestone discoveries in pharmacology and biochemistry ranging from the original formulation of the receptor concept, the first isolation and structural analysis of a receptor protein (the nAChR) to the identification, localization, and differentiation of its diverse subtypes and their validation as a target for therapeutic intervention. Among the venom-derived compounds, α-neurotoxins and α-conotoxins provide the largest families and still represent indispensable pharmacological tools. Application of modified α-neurotoxins provided substantial structural and functional details of the nAChR long before high resolution structures were available. α-bungarotoxin represents not only a standard pharmacological tool and label in nAChR research but also for unrelated proteins tagged with a minimal α-bungarotoxin binding motif. A major advantage of α-conotoxins is their smaller size, as well as superior selectivity for diverse nAChR subtypes that allows their development into ligands with optimized pharmacological and chemical properties and potentially novel drugs. In the following, these two groups of nAChR antagonists will be described focusing on their respective roles in the structural and functional characterization of nAChRs and their development into research tools. In addition, we provide a comparative overview of the diverse α-conotoxin selectivities that can serve as a practical guide for both structure activity studies and subtype classification. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Sébastien Dutertre
- Institut des Biomolécules Max Mousseron, UMR 5247, Université Montpellier - CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Annette Nicke
- Walther Straub Institute for Pharmacology and Toxicology, Ludwig-Maximilians-Universität, Nußbaumstr. 26, 80336 Munich, Germany.
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str.16/10, Moscow 117999, Russian Federation
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16
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Vulfius CA, Spirova EN, Serebryakova MV, Shelukhina IV, Kudryavtsev DS, Kryukova EV, Starkov VG, Kopylova NV, Zhmak MN, Ivanov IA, Kudryashova KS, Andreeva TV, Tsetlin VI, Utkin YN. Peptides from puff adder Bitis arietans venom, novel inhibitors of nicotinic acetylcholine receptors. Toxicon 2016; 121:70-76. [PMID: 27576061 DOI: 10.1016/j.toxicon.2016.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 07/19/2016] [Accepted: 08/25/2016] [Indexed: 11/17/2022]
Abstract
Phospholipase A2 (named bitanarin) possessing capability to block nicotinic acetylcholine receptors (nAChRs) was isolated earlier (Vulfius et al., 2011) from puff adder Bitis arietans venom. Further studies indicated that low molecular weight fractions of puff adder venom inhibit nAChRs as well. In this paper, we report on isolation from this venom and characterization of three novel peptides called baptides 1, 2 and 3 that reversibly block nAChRs. To isolate the peptides, the venom of B. arietans was fractionated by gel-filtration and reversed phase chromatography. The amino acid sequences of peptides were established by de novo sequencing using MALDI mass spectrometry. Baptide 1 comprised 7, baptides 2 and 3-10 amino acid residues, the latter being acetylated at the N-terminus. This is the first indication for the presence of such post-translational modification in snake venom proteins. None of the peptides contain cysteine residues. For biological activity studies the peptides were prepared by solid phase peptide synthesis. Baptide 3 and 2 blocked acetylcholine-elicited currents in isolated Lymnaea stagnalis neurons with IC50 of about 50 μM and 250 μM, respectively. In addition baptide 2 blocked acetylcholine-induced currents in muscle nAChR heterologously expressed in Xenopus oocytes with IC50 of about 3 μM. The peptides did not compete with radioactive α-bungarotoxin for binding to Torpedo and α7 nAChRs at concentration up to 200 μM that suggests non-competitive mode of inhibition. Calcium imaging studies on α7 and muscle nAChRs heterologously expressed in mouse neuroblastoma Neuro2a cells showed that on α7 receptor baptide 2 inhibited acetylcholine-induced increasing intracellular calcium concentration with IC50 of 20.6 ± 3.93 μM. On both α7 and muscle nAChRs the suppression of maximal response to acetylcholine by about 50% was observed at baptide 2 concentration of 25 μM, the value being close to IC50 on α7 nAChR. These data are in accord with non-competitive inhibition as follows from α-bungarotoxin binding experiments. The described peptides are the shortest peptides without disulfide bridges isolated from animal venom and capable to inhibit nAChR by non-competitive way.
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Affiliation(s)
- Catherine A Vulfius
- Institute of Cell Biophysics, Russian Academy of Sciences, Ul. Institutskaya 3, Pushchino Moscow Region, 142290, Russia
| | - Ekaterina N Spirova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Marina V Serebryakova
- Belozersky Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Irina V Shelukhina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Denis S Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Elena V Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Vladislav G Starkov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Nina V Kopylova
- Moscow State Pedagogical University, Ul. M. Pirogovskaya 1/1, Moscow, 119991, Russia
| | - Maxim N Zhmak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia; OOO Syneuro, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Igor A Ivanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Ksenia S Kudryashova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Tatyana V Andreeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia
| | - Yuri N Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya 16/10, Moscow, 117997, Russia.
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17
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Nicotinic receptor involvement in regulation of functions of mouse neutrophils from inflammatory site. Immunobiology 2016; 221:761-72. [DOI: 10.1016/j.imbio.2016.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/30/2016] [Indexed: 01/08/2023]
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18
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Anti-hypersensitive effect of intramuscular administration of αO-conotoxin GeXIVA[1,2] and GeXIVA[1,4] in rats of neuropathic pain. Prog Neuropsychopharmacol Biol Psychiatry 2016; 66:112-119. [PMID: 26706456 DOI: 10.1016/j.pnpbp.2015.12.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/12/2015] [Accepted: 12/15/2015] [Indexed: 11/23/2022]
Abstract
αO-conotoxin GeXIVA (GeXIVA) is a potent antagonist of α9α10 nicotinic acetylcholine receptors (nAChRs), which has four Cys residues and three disulfide isomers. Among the 3 isomers, both GeXIVA[1,2] (bead isomer) and GeXIVA[1,4] (ribbon isomer) showed potent block on α9α10 nAChRs with close low nanomolar IC50s. Here we report that anti-hypersensitive effects of the bead and ribbon isomers in the chronic constriction injury (CCI) model of neuropathic pain and acute pain model of tail flick test. Treatment was started and continued for 7 or 14days after the development of hyperalgesia which was induced by CCI surgery. GeXIVA[1,2] and GeXIVA[1,4] significantly reduced mechanical allodynia in CCI rats without tolerance, in which GeXIVA[1,2] remained up to two weeks after intramuscular administration of the toxins was ceased. The pain reliever effect of GeXIVA[1,2] on neuropathic rats was slightly better than GeXIVA[1,4]. The two isomers did not suppress the acute thermal pain behaviors significantly when they were tested in the tail flick model by intramuscular bolus injection. Both GeXIVA[1,2] and GeXIVA[1,4] had no significant effect on performance of rats in the accelerating rotarod test after intramuscular injections. This suggests that αO-conotoxin GeXIVA[1,2] and GeXIVA[1,4] may offer new strategies to the treatment of neuropathic pain.
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19
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Morales-González D, Flores-Martínez E, Zamora-Bustillos R, Rivera-Reyes R, Michel-Morfín JE, Landa-Jaime V, Falcón A, Aguilar MB. Diversity of A-conotoxins of three worm-hunting cone snails (Conus brunneus, Conus nux, and Conus princeps) from the Mexican Pacific coast. Peptides 2015; 68:25-32. [PMID: 25703301 DOI: 10.1016/j.peptides.2015.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/31/2015] [Accepted: 02/11/2015] [Indexed: 12/31/2022]
Abstract
Conus marine snails (∼500 species) are tropical predators that use venoms mainly to capture prey and defend themselves from predators. The principal components of these venoms are peptides that are known as "conotoxins" and generally comprise 7-40 amino acid residues, including 0-5 disulfide bridges and distinct posttranslational modifications. The most common molecular targets of conotoxins are voltage- and ligand-gated ion channels, G protein-coupled receptors, and neurotransmitter transporters, to which they bind, typically, with high affinity and specificity. Due to these properties, several conotoxins have become molecular probes, medicines, and leads for drug design. Conotoxins have been classified into genetic superfamilies based on the signal sequence of their precursors, and into pharmacological families according to their molecular targets. The objective of this work was to identify and analyze partial cDNAs encoding conotoxin precursors belonging to the A superfamily from Conus brunneus, Conus nux, and Conus princeps. These are vermivorous species of the Mexican Pacific coast from which only one A-conotoxin, and few O- and I2-conotoxins have been reported. Employing RT-PCR, we identified 30 distinct precursors that contain 13 different predicted mature toxins. With the exception of two groups of four highly similar peptides, these toxins are diverse at both the sequence and the physicochemical levels, and they belong to the 4/3, 4/4, 4/5, 4/6, and 4/7 structural subfamilies. These toxins are predicted to target diverse nicotinic acetylcholine receptor (nAChR) subtypes: nx1d, muscle; pi1a-pi1d, α3β2, α7, and/or α9α10; br1a, muscle, α3β4, and/or α4β2; and nx1a-nx1c/pi1g and pi1h, α3β2, α3β4, α9β10, and/or α7.
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Affiliation(s)
- Daniel Morales-González
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico; Maestría en Ciencias (Neurobiología), Universidad Nacional Autónoma de México, Mexico
| | - Ernesto Flores-Martínez
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico; Maestría en Ciencias (Neurobiología), Universidad Nacional Autónoma de México, Mexico
| | - Roberto Zamora-Bustillos
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico; Laboratorio de Genética Molecular, Instituto Tecnológico de Conkal, Conkal, Yucatán 97345, Mexico
| | - Reginaldo Rivera-Reyes
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico
| | - Jesús Emilio Michel-Morfín
- Departamento de Estudios para el Desarrollo Sustentable de Zonas Costeras, CUCSUR-Universidad de Guadalajara, Gómez Farías 82, San Patricio-Melaque, Jalisco 48980, Mexico
| | - Víctor Landa-Jaime
- Departamento de Estudios para el Desarrollo Sustentable de Zonas Costeras, CUCSUR-Universidad de Guadalajara, Gómez Farías 82, San Patricio-Melaque, Jalisco 48980, Mexico; Posgrado en Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Nayarit, Mexico
| | - Andrés Falcón
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico
| | - Manuel B Aguilar
- Laboratorio de Neurofarmacología Marina, Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76230, Mexico.
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20
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In silico analysis of binding of neurotoxic venom ligands with acetylcholinesterase for therapeutic use in treatment of Alzheimer’s disease. J Theor Biol 2015; 372:107-17. [DOI: 10.1016/j.jtbi.2015.02.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 02/22/2015] [Accepted: 02/25/2015] [Indexed: 01/08/2023]
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21
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Wan J, Huang JX, Vetter I, Mobli M, Lawson J, Tae HS, Abraham N, Paul B, Cooper MA, Adams DJ, Lewis RJ, Alewood PF. α-Conotoxin Dendrimers Have Enhanced Potency and Selectivity for Homomeric Nicotinic Acetylcholine Receptors. J Am Chem Soc 2015; 137:3209-12. [DOI: 10.1021/jacs.5b00244] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jingjing Wan
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
| | - Johnny X. Huang
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
| | - Irina Vetter
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
- School
of Pharmacy, The University of Queensland, Woolloongabba, Queensland 4102, Australia
| | - Mehdi Mobli
- Centre
for Advanced Imaging, The University of Queensland, St Lucia Queensland 4072, Australia
| | - Joshua Lawson
- Health
Innovations Research Institute, RMIT University, Bundoora, Victoria 3083, Australia
| | - Han-Shen Tae
- Health
Innovations Research Institute, RMIT University, Bundoora, Victoria 3083, Australia
| | - Nikita Abraham
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
| | - Blessy Paul
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
| | - Matthew A. Cooper
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
| | - David J. Adams
- Health
Innovations Research Institute, RMIT University, Bundoora, Victoria 3083, Australia
| | - Richard J. Lewis
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
| | - Paul F. Alewood
- Institute
of Molecular Bioscience, The University of Queensland, St Lucia Queensland 4072, Australia
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22
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Akondi KB, Muttenthaler M, Dutertre S, Kaas Q, Craik DJ, Lewis RJ, Alewood PF. Discovery, synthesis, and structure-activity relationships of conotoxins. Chem Rev 2014; 114:5815-47. [PMID: 24720541 PMCID: PMC7610532 DOI: 10.1021/cr400401e] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | - Sébastien Dutertre
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
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23
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Sambasivarao SV, Roberts J, Bharadwaj VS, Slingsby JG, Rohleder C, Mallory C, Groome JR, McDougal OM, Maupin CM. Acetylcholine promotes binding of α-conotoxin MII at α3 β2 nicotinic acetylcholine receptors. Chembiochem 2014; 15:413-24. [PMID: 24420650 DOI: 10.1002/cbic.201300577] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Indexed: 11/09/2022]
Abstract
α-Conotoxin MII (α-CTxMII) is a 16-residue peptide with the sequence GCCSNPVCHLEHSNLC, containing Cys2-Cys8 and Cys3-Cys16 disulfide bonds. This peptide, isolated from the venom of the marine cone snail Conus magus, is a potent and selective antagonist of neuronal nicotinic acetylcholine receptors (nAChRs). To evaluate the impact of channel-ligand interactions on ligand-binding affinity, homology models of the heteropentameric α3β2-nAChR were constructed. The models were created in MODELLER with the aid of experimentally characterized structures of the Torpedo marmorata-nAChR (Tm-nAChR, PDB ID: 2BG9) and the Aplysia californica-acetylcholine binding protein (Ac-AChBP, PDB ID: 2BR8) as templates for the α3- and β2-subunit isoforms derived from rat neuronal nAChR primary amino acid sequences. Molecular docking calculations were performed with AutoDock to evaluate interactions of the heteropentameric nAChR homology models with the ligands acetylcholine (ACh) and α-CTxMII. The nAChR homology models described here bind ACh with binding energies commensurate with those of previously reported systems, and identify critical interactions that facilitate both ACh and α-CTxMII ligand binding. The docking calculations revealed an increased binding affinity of the α3β2-nAChR for α-CTxMII with ACh bound to the receptor, and this was confirmed through two-electrode voltage clamp experiments on oocytes from Xenopus laevis. These findings provide insights into the inhibition and mechanism of electrostatically driven antagonist properties of the α-CTxMIIs on nAChRs.
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Affiliation(s)
- Somisetti V Sambasivarao
- Chemical and Biological Engineering Department, Colorado School of Mines, 1500 Illinois Street, Golden, CO 80401 (USA)
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24
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Luo S, Zhangsun D, Schroeder CI, Zhu X, Hu Y, Wu Y, Weltzin MM, Eberhard S, Kaas Q, Craik DJ, McIntosh JM, Whiteaker P. A novel α4/7-conotoxin LvIA from Conus lividus that selectively blocks α3β2 vs. α6/α3β2β3 nicotinic acetylcholine receptors. FASEB J 2014; 28:1842-53. [PMID: 24398291 DOI: 10.1096/fj.13-244103] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This study was performed to discover and characterize the first potent α3β2-subtype-selective nicotinic acetylcholine receptor (nAChR) ligand. A novel α4/7-conotoxin, α-CTxLvIA, was cloned from Conus lividus. Its pharmacological profile at Xenopus laevis oocyte-expressed rat nAChR subtypes was determined by 2-electrode voltage-clamp electrophysiology, and its 3-dimensional (3D) structure was determined by NMR spectroscopy. α-CTx LvIA is a 16-aa C-terminally-amidated peptide with 2-disulfide bridges. Using rat subunits expressed in Xenopus oocytes, we found the highest affinity of α-CTxLvIA was for α3β2 nAChRs (IC50 8.7 nM), where blockade was reversible within 2 min. IC50 values were >100 nM at α6/α3β2β3, α6/α3β4, and α3β4 nAChRs, and ≥3 μM at all other subtypes tested. α3β2 vs. α6β2 subtype selectivity was confirmed for human-subunit nAChRs with much greater preference (300-fold) for α3β2 over α6β2 nAChRs. This is the first α-CTx reported to show high selectivity for human α3β2 vs. α6β2 nAChRs. α-CTxLvIA adopts two similarly populated conformations water: one (assumed to be bioactive) is highly structured, whereas the other is mostly random coil in nature. Selectivity differences with the similarly potent, but less selective, α3β2 nAChR antagonist α-CTx PeIA probably reside within the three residues, which differ in loop 2, given their otherwise similar 3D structures. α4/7-CTx LvIA is a new, potent, selective α3β2 nAChR antagonist, which will enable detailed studies of α3β2 nAChR structure, function, and physiological roles.
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Affiliation(s)
- Sulan Luo
- 1Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University; Haikou, Hainan, 570228 China.
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25
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Luo S, Zhangsun D, Zhu X, Wu Y, Hu Y, Christensen S, Harvey PJ, Akcan M, Craik DJ, McIntosh JM. Characterization of a novel α-conotoxin TxID from Conus textile that potently blocks rat α3β4 nicotinic acetylcholine receptors. J Med Chem 2013; 56:9655-63. [PMID: 24200193 DOI: 10.1021/jm401254c] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The α3β4 nAChRs are implicated in pain sensation in the PNS and addiction to nicotine in the CNS. We identified an α-4/6-conotoxin (CTx) TxID from Conus textile. The new toxin consists of 15 amino acid residues with two disulfide bonds. TxID was synthesized using solid phase methods, and the synthetic peptide was functionally tested on nAChRs heterologously expressed in Xenopus laevis oocytes. TxID blocked rat α3β4 nAChRs with a 12.5 nM IC50, which places it among the most potent α3β4 nAChR antagonists. TxID also blocked the closely related α6/α3β4 with a 94 nM IC50 but showed little activity on other nAChR subtypes. NMR analysis showed that two major structural isomers exist in solution, one of which adopts a regular α-CTx fold but with different surface charge distribution to other 4/6 family members. α-CTx TxID is a novel tool with which to probe the structure and function of α3β4 nAChRs.
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Affiliation(s)
- Sulan Luo
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drug of Haikou, Hainan University , Haikou Hainan, 570228, China
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26
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Kendel Y, Melaun C, Kurz A, Nicke A, Peigneur S, Tytgat J, Wunder C, Mebs D, Kauferstein S. Venomous secretions from marine snails of the Terebridae family target acetylcholine receptors. Toxins (Basel) 2013; 5:1043-50. [PMID: 23698359 PMCID: PMC3709278 DOI: 10.3390/toxins5051043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 05/13/2013] [Accepted: 05/13/2013] [Indexed: 11/16/2022] Open
Abstract
Venoms from cone snails (Conidae) have been extensively studied during the last decades, but those from other members of the suborder Toxoglossa, such as of Terebridae and Turridae superfamilies attracted less interest so far. Here, we report the effects of venom and gland extracts from three species of the superfamily Terebridae. By 2-electrode voltage-clamp technique the gland extracts were tested on Xenopus oocytes expressing nicotinic acetylcholine receptors (nAChRs) of rat neuronal (α3β2, α3β4, α4β2, α4β4, α7) and muscle subtypes (α1β1γδ), and expressing potassium (Kv1.2 and Kv1.3) and sodium channels (Nav1.2, 1.3, 1.4, 1.6). The extracts were shown to exhibit remarkably high inhibitory activities on almost all nAChRs tested, in particular on the α7 subtype suggesting the presence of peptides of the A-superfamily from the venom of Conus species. In contrast, no effects on the potassium and sodium channels tested were observed. The venoms of terebrid snails may offer an additional source of novel biologically active peptides.
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Affiliation(s)
- Yvonne Kendel
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, Frankfurt D-60596, Germany; E-Mails: (Y.K.); (A.K.); (C.W.)
| | - Christian Melaun
- Biodiversity and Climate Research Center (BiK-F), Senckenberganlage 25, Frankfurt D-60325, Germany; E-Mails: (C.M.); (D.M.)
- Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt D-60325, Germany
| | - Alexander Kurz
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, Frankfurt D-60596, Germany; E-Mails: (Y.K.); (A.K.); (C.W.)
| | - Annette Nicke
- Max-Planck-Institute of Experimental Medicine, Hermann-Rein-Str. 3, Göttingen D-37075, Germany; E-Mail:
| | - Steve Peigneur
- Laboratory of Toxicology and Pharmacology, University of Leuven, Campus Gatshuisberg, Herestraat 49, Leuven B-3000, Belgium; E-Mails: (S.P.); (J.T.)
| | - Jan Tytgat
- Laboratory of Toxicology and Pharmacology, University of Leuven, Campus Gatshuisberg, Herestraat 49, Leuven B-3000, Belgium; E-Mails: (S.P.); (J.T.)
| | - Cora Wunder
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, Frankfurt D-60596, Germany; E-Mails: (Y.K.); (A.K.); (C.W.)
| | - Dietrich Mebs
- Biodiversity and Climate Research Center (BiK-F), Senckenberganlage 25, Frankfurt D-60325, Germany; E-Mails: (C.M.); (D.M.)
- Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt D-60325, Germany
| | - Silke Kauferstein
- Institute of Legal Medicine, University of Frankfurt, Kennedyallee 104, Frankfurt D-60596, Germany; E-Mails: (Y.K.); (A.K.); (C.W.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-69-6301-7564; Fax: +49-69-6301-5882
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27
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Abstract
Conopeptides from the venoms of marine snails have attracted much interest as leads in drug design. Currently, one drug, Prialt(®), is on the market as a treatment for chronic neuropathic pain. Conopeptides target a range of ion channels, receptors and transporters, and are typically small, relatively stable peptides that are generally amenable to production using solid-phase peptide synthesis. With only a small fraction of the predicted diversity of conopeptides examined so far, these peptides represent an exciting and largely untapped resource for drug discovery. Recent efforts at chemically re-engineering conopeptides to improve their biopharmaceutical properties promise to accelerate the translation of these fascinating marine peptides to the clinic.
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28
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Beissner M, Dutertre S, Schemm R, Danker T, Sporning A, Grubmüller H, Nicke A. Efficient binding of 4/7 α-conotoxins to nicotinic α4β2 receptors is prevented by Arg185 and Pro195 in the α4 subunit. Mol Pharmacol 2012; 82:711-8. [PMID: 22802270 DOI: 10.1124/mol.112.078683] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
α-Conotoxins are subtype-selective nicotinic acetylcholine receptor (nAChR) antagonists. Although potent α3β2 nAChR-selective α-conotoxins have been identified, currently characterized α-conotoxins show no or only weak affinity for α4β2 nAChRs, which are, besides α7 receptors, the most abundant nAChRs in the mammalian brain. To identify the determinants responsible for this difference, we substituted selected amino acid residues in the ligand-binding domain of the α4 subunit by the corresponding residues in the α3 subunit. Two-electrode voltage clamp analysis of these mutants revealed increased affinity of α-conotoxins MII, TxIA, and [A10L]TxIA at the α4(R185I)β2 receptor. Conversely, α-conotoxin potency was reduced at the reverse α3(I186R)β2 mutant. Replacement of α4Arg185 by alanine, glutamate, and lysine demonstrated that a positive charge in this position prevents α-conotoxin binding. Combination of the R185I mutation with a P195Q mutation outside the binding site but in loop C completely transferred high α-conotoxin potency to the α4β2 receptor. Molecular dynamics simulations of homology models with docked α-conotoxin indicate that these residues control access to the α-conotoxin binding site.
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Affiliation(s)
- Mirko Beissner
- Department of Neurochemistry, Max Planck Institute for Brain Research, Frankfurt, Germany
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29
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Kasheverov IE, Zhmak MN, Khruschov AY, Tsetlin VI. Design of new α-conotoxins: from computer modeling to synthesis of potent cholinergic compounds. Mar Drugs 2011; 9:1698-1714. [PMID: 22072993 PMCID: PMC3210602 DOI: 10.3390/md9101698] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 08/29/2011] [Accepted: 09/16/2011] [Indexed: 11/16/2022] Open
Abstract
A series of 14 new analogs of α-conotoxin PnIA Conus pennaceus was synthesized and tested for binding to the human α7 nicotinic acetylcholine receptor (nAChR) and acetylcholine-binding proteins (AChBP) Lymnaea stagnalis and Aplysia californica. Based on computer modeling and the X-ray structure of the A. californica AChBP complex with the PnIA[A10L, D14K] analog, single and multiple amino acid substitutions were introduced in α-conotoxin PnIA aimed at compounds of higher affinity and selectivity. Three analogs, PnIA[L5H], PnIA[A10L, D14K] and PnIA[L5R, A10L, D14R], have high affinities for AChBPs or α7 nAChR, as found in competition with radioiodinated α-bungarotoxin. That is why we prepared radioiodinated derivatives of these α-conotoxins, demonstrated their specific binding and found that among the tested synthetic analogs, most had almost 10-fold higher affinity in competition with radioactive α-conotoxins as compared to competition with radioactive α-bungarotoxin. Thus, radioiodinated α-conotoxins are a more sensitive tool for checking the activity of novel α-conotoxins and other compounds quickly dissociating from the receptor complexes.
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Affiliation(s)
- Igor E. Kasheverov
- Author to whom correspondence should be addressed; E-Mail: or ; Tel.: +7-495-330-7374; Fax: +7-495-335-5733
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Holtman JR, Dwoskin LP, Dowell C, Wala EP, Zhang Z, Crooks PA, McIntosh JM. The novel small molecule α9α10 nicotinic acetylcholine receptor antagonist ZZ-204G is analgesic. Eur J Pharmacol 2011; 670:500-8. [PMID: 21944926 DOI: 10.1016/j.ejphar.2011.08.053] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 08/04/2011] [Accepted: 08/27/2011] [Indexed: 01/15/2023]
Abstract
Chronic pain is inadequately managed with currently available classes of analgesic drugs. Recently, peptide antagonists of the α9α10 nicotinic acetylcholine receptor were shown to be analgesic. The present study was conducted to characterize a novel small molecule, non-peptide antagonist at nicotinic receptors. The tetrakis-quaternary ammonium compound ZZ-204G was evaluated for functional activity on cloned nicotinic receptors expressed in Xenopus oocytes. In-vivo efficacy was assessed in rat models of tonic inflammatory pain (formalin test), neuropathic pain (chronic constriction nerve injury), and thermal nociception (tail flick test). ZZ-204G was an antagonist at nicotinic receptors inhibiting the α9α10 subtype with an IC₅₀ of 0.51 (0.35-0.72) nM. Antagonist activity at other nicotinic subtypes (α1β1δε, α2β2, α2β4, α3β2, α3β4, α4β2, α4β4, α6/α3β2β3, α6/α3β4 and α7) was 10-1000-fold lower than at the α9α10 subtype. In competition binding assays, the k(i) of ZZ-204G at γ-aminobutyric acid(A), serotonin(3), γ-aminobutyric acid(B), κ- and μ-opioid receptors was 1000- to >10,000-fold lower than at α9α10 nicotinic receptors. Parenteral administration of ZZ-204G dose-dependently decreased nociceptive behaviors (paw flinches) in the formalin test and mechanical hyperalgesia in the chronic constriction nerve injury model of neuropathic pain. ZZ-204G was not antinociceptive in the tail flick assay. Results from the rotarod assay indicated that lower doses of ZZ-204G that were analgesic did not alter motor function. In summary, ZZ-204G represents a prototype small molecule antagonist for α9α10 nicotinic receptors and provides a novel molecular scaffold for analgesic agents with the potential to treat chronic inflammatory or neuropathic pain.
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Affiliation(s)
- Joseph R Holtman
- Department of Anesthesiology, Loyola School of Medicine, Maywood, IL, USA
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31
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Nasiripourdori A, Taly V, Grutter T, Taly A. From toxins targeting ligand gated ion channels to therapeutic molecules. Toxins (Basel) 2011; 3:260-93. [PMID: 22069709 PMCID: PMC3202823 DOI: 10.3390/toxins3030260] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/01/2011] [Accepted: 03/16/2011] [Indexed: 11/21/2022] Open
Abstract
Ligand-gated ion channels (LGIC) play a central role in inter-cellular communication. This key function has two consequences: (i) these receptor channels are major targets for drug discovery because of their potential involvement in numerous human brain diseases; (ii) they are often found to be the target of plant and animal toxins. Together this makes toxin/receptor interactions important to drug discovery projects. Therefore, toxins acting on LGIC are presented and their current/potential therapeutic uses highlighted.
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Affiliation(s)
| | - Valérie Taly
- Laboratory of Chemical Biology, Institut de Science et d'Ingénierie Supramoléculaires; ISIS/Université de Strasbourg, CNRS-UMR 7006, 8, allée Gaspard Monge, BP 70028, F-67083, Strasbourg Cedex, France;
| | - Thomas Grutter
- Laboratoire de Biophysicochimie des Récepteurs Canaux, UMR 7199 “Conception et Application de Molécules Bioactives” CNRS-Université de Strasbourg, 74 Route du Rhin-BP 60024, 67401 Illkirch Cedex, France;
| | - Antoine Taly
- Laboratoire de Biophysicochimie des Récepteurs Canaux, UMR 7199 “Conception et Application de Molécules Bioactives” CNRS-Université de Strasbourg, 74 Route du Rhin-BP 60024, 67401 Illkirch Cedex, France;
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32
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Azarn L, Maskos U, Changeux JP, Dowell CD, Christensen S, Biasi MD, McIntosh JM. α‐Conotoxin BuIA[T5A;P6O]: a novel ligand that discriminates between 06 β4 and 0:6 β2 nicotinic acetylcholine receptors and blocks nicotine‐stimulated norepinephrine release. FASEB J 2010. [DOI: 10.1096/fj.10.166272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Layla Azarn
- Department of BiologyUniversity of Utah, Salt Lake City Utah USA
| | - Uwe Maskos
- Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Institut Pasteur Paris France
| | - Jean-Pierre Changeux
- Unité Neurobiologie Intégrative des Systèmes Cholinergiques, Institut Pasteur Paris France
| | - Cheryl D. Dowell
- Department of BiologyUniversity of Utah, Salt Lake City Utah USA
| | - Sean Christensen
- Department of BiologyUniversity of Utah, Salt Lake City Utah USA
| | - Mariella De Biasi
- Department of Neuroscience and Graduate Program in Translational Biology and Molecular MedicineBaylor College of Medicine Houston Texas USA
| | - J. Michael McIntosh
- Department of BiologyUniversity of Utah, Salt Lake City Utah USA
- Department of PsychiatryUniversity of Utah, Salt Lake City Utah USA
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33
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Muttenthaler M, Andersson A, de Araujo AD, Dekan Z, Lewis RJ, Alewood PF. Modulating Oxytocin Activity and Plasma Stability by Disulfide Bond Engineering. J Med Chem 2010; 53:8585-96. [DOI: 10.1021/jm100989w] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, 4072 St. Lucia, Brisbane, Queensland
| | - Asa Andersson
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, 4072 St. Lucia, Brisbane, Queensland
| | - Aline D. de Araujo
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, 4072 St. Lucia, Brisbane, Queensland
| | - Zoltan Dekan
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, 4072 St. Lucia, Brisbane, Queensland
| | - Richard J. Lewis
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, 4072 St. Lucia, Brisbane, Queensland
| | - Paul F. Alewood
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, 4072 St. Lucia, Brisbane, Queensland
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34
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Peng C, Chen W, Sanders T, Chew G, Liu J, Hawrot E, Chi C. Chemical synthesis and characterization of two α4/7-conotoxins. Acta Biochim Biophys Sin (Shanghai) 2010; 42:745-53. [PMID: 20801929 DOI: 10.1093/abbs/gmq074] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
α-Conotoxins are small disulfide-constrained peptides that act as potent and selective antagonists on specific subtypes of nicotinic acetylcholine receptors (nAChRs). We previously cloned two α-conotoxins, Mr1.1 from the molluscivorous Conus marmoreus and Lp1.4 from the vermivorous Conus leopardus. Both of them have the typical 4/7-type framework of the subfamily of α-conotoxins that act on neuronal nAChRs. In this work, we chemically synthesized these two toxins and characterized their functional properties. The synthetic Mr1.1 could primarily inhibit acetylcholine (ACh)-evoked currents reversibly in the oocyte-expressed rat α7 nAChR, whereas Lp1.4 was an unexpected specific blocker of the mouse fetal muscle α1β1γδ receptor. Although their inhibition affinities were relatively low, their unique receptor recognition profiles make them valuable tools for toxin-receptor interaction studies. Mr1.1 could also suppress the inflammatory response to pain in vivo, suggesting that it should be further investigated with respect to its molecular role in analgesia and its mechanism or therapeutic target for the treatment of pain.
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Affiliation(s)
- Can Peng
- Institute of Protein Research, Tongji University, Shanghai, China
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35
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Azam L, Maskos U, Changeux JP, Dowell CD, Christensen S, De Biasi M, McIntosh JM. α-Conotoxin BuIA[T5A;P6O]: a novel ligand that discriminates between α6ß4 and α6ß2 nicotinic acetylcholine receptors and blocks nicotine-stimulated norepinephrine release. FASEB J 2010; 24:5113-23. [PMID: 20739611 DOI: 10.1096/fj.10-166272] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
α6* (asterisk indicates the presence of additional subunits) nicotinic acetylcholine receptors (nAChRs) are broadly implicated in catecholamine-dependent disorders that involve attention, motor movement, and nicotine self-administration. Different molecular forms of α6 nAChRs mediate catecholamine release, but receptor differentiation is greatly hampered by a paucity of subtype selective ligands. α-Conotoxins are nAChR-targeted peptides used by Conus species to incapacitate prey. We hypothesized that distinct conotoxin-binding kinetics could be exploited to develop a series of selective probes to enable study of native receptor subtypes. Proline6 of α-conotoxin BuIA was found to be critical for nAChR selectivity; substitution of proline6 with 4-hydroyxproline increased the IC(50) by 2800-fold at α6/α3β2β3 but only by 6-fold at α6/α3β4 nAChRs (to 1300 and 12 nM, respectively). We used conotoxin probes together with subunit-null mice to interrogate nAChR subtypes that modulate hippocampal norepinephrine release. Release was abolished in α6-null mutant mice. α-Conotoxin BuIA[T5A;P6O] partially blocked norepinephrine release in wild-type controls but failed to block release in β4(-/-) mice. In contrast, BuIA[T5A;P6O] failed to block dopamine release in the wild-type striatum known to contain α6β2* nAChRs. BuIA[T5A;P6O] is a novel ligand for distinguishing between closely related α6* nAChRs; α6β4* nAChRs modulate norepinephrine release in hippocampus but not dopamine release in striatum.
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Affiliation(s)
- Layla Azam
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
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36
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Nyce HL, Stober ST, Abrams CF, White MM. Mapping spatial relationships between residues in the ligand-binding domain of the 5-HT3 receptor using a molecular ruler. Biophys J 2010; 98:1847-55. [PMID: 20441748 DOI: 10.1016/j.bpj.2010.01.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/11/2010] [Accepted: 01/14/2010] [Indexed: 12/24/2022] Open
Abstract
The serotonin 5-HT(3) receptor (5-HT(3)R) is a member of the Cys-loop ligand-gated ion channel family. We used a combination of site-directed mutagenesis, homology modeling, and ligand-docking simulations to analyze antagonist-receptor interactions. Mutation of E236, which is near loop C of the binding site, to aspartate prevents expression of the receptor on the cell surface, and no specific ligand binding can be detected. On the other hand, mutation to glutamine, asparagine, or alanine produces receptors that are expressed on the cell surface, but decreases receptor affinity for the competitive antagonist d-tubocurarine (dTC) 5-35-fold. The results of a double-mutant cycle analysis employing a panel of dTC analogs to identify specific points of interactions between the dTC analogs and E236 are consistent with E236 making a direct physical interaction with the 12 -OH of dTC. dTC is a rigid molecule of known three-dimensional structure. Together with previous studies linking other regions of dTC to specific residues in the binding site, these data allow us to define the relative spatial arrangement of three different residues in the ligand-binding site: R92 (loop D), N128 (loop A), and E236 (near loop C). Molecular modeling employing these distance constraints followed by molecular-dynamics simulations produced a dTC/receptor complex consistent with the experimental data. The use of the rigid ligands as molecular rulers in conjunction with double-mutant cycle analysis provides a means of mapping the relative positions of various residues in the ligand-binding site of any ligand-receptor complex, and thus is a useful tool for delineating the architecture of the binding site.
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Affiliation(s)
- Heather L Nyce
- Department of Biochemistry, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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37
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Muttenthaler M, Nevin ST, Grishin AA, Ngo ST, Choy PT, Daly NL, Hu SH, Armishaw CJ, Wang CIA, Lewis RJ, Martin JL, Noakes PG, Craik DJ, Adams DJ, Alewood PF. Solving the alpha-conotoxin folding problem: efficient selenium-directed on-resin generation of more potent and stable nicotinic acetylcholine receptor antagonists. J Am Chem Soc 2010; 132:3514-22. [PMID: 20163143 DOI: 10.1021/ja910602h] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Alpha-conotoxins are tightly folded miniproteins that antagonize nicotinic acetylcholine receptors (nAChR) with high specificity for diverse subtypes. Here we report the use of selenocysteine in a supported phase method to direct native folding and produce alpha-conotoxins efficiently with improved biophysical properties. By replacing complementary cysteine pairs with selenocysteine pairs on an amphiphilic resin, we were able to chemically direct all five structural subclasses of alpha-conotoxins exclusively into their native folds. X-ray analysis at 1.4 A resolution of alpha-selenoconotoxin PnIA confirmed the isosteric character of the diselenide bond and the integrity of the alpha-conotoxin fold. The alpha-selenoconotoxins exhibited similar or improved potency at rat diaphragm muscle and alpha3beta4, alpha7, and alpha1beta1 deltagamma nAChRs expressed in Xenopus oocytes plus improved disulfide bond scrambling stability in plasma. Together, these results underpin the development of more stable and potent nicotinic antagonists suitable for new drug therapies, and highlight the application of selenocysteine technology more broadly to disulfide-bonded peptides and proteins.
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Affiliation(s)
- Markus Muttenthaler
- Institute for Molecular Bioscience, Division of Chemistry and Structural Biology, The University of Queensland, Brisbane, Queensland 4072, Australia
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38
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Armishaw CJ. Synthetic α-conotoxin mutants as probes for studying nicotinic acetylcholine receptors and in the development of novel drug leads. Toxins (Basel) 2010; 2:1471-99. [PMID: 22069647 PMCID: PMC3153239 DOI: 10.3390/toxins2061471] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 05/27/2010] [Accepted: 06/11/2010] [Indexed: 11/19/2022] Open
Abstract
α-Conotoxins are peptide neurotoxins isolated from venomous marine cone snails that are potent and selective antagonists for different subtypes of nicotinic acetylcholine receptors (nAChRs). As such, they are valuable probes for dissecting the role that nAChRs play in nervous system function. In recent years, extensive insight into the binding mechanisms of α-conotoxins with nAChRs at the molecular level has aided in the design of synthetic analogs with improved pharmacological properties. This review examines the structure-activity relationship studies involving α-conotoxins as research tools for studying nAChRs in the central and peripheral nervous systems and their use towards the development of novel therapeutics.
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Affiliation(s)
- Christopher J Armishaw
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St Lucie, FL 34987, USA.
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39
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Bingham JP, Mitsunaga E, Bergeron ZL. Drugs from slugs--past, present and future perspectives of omega-conotoxin research. Chem Biol Interact 2010; 183:1-18. [PMID: 19800874 DOI: 10.1016/j.cbi.2009.09.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 09/03/2009] [Accepted: 09/24/2009] [Indexed: 12/18/2022]
Abstract
Peptides from the venom of carnivorous cone shells have provided six decades of intense research, which has led to the discovery and development of novel analgesic peptide therapeutics. Our understanding of this unique natural marine resource is however somewhat limited. Given the past pharmacological record, future investigations into the toxinology of these highly venomous tropical marine snails will undoubtedly yield other highly selective ion channel inhibitors and modulators. With over a thousand conotoxin-derived sequences identified to date, those identified as ion channel inhibitors represent only a small fraction of the total. Here we discuss our present understanding of conotoxins, focusing on the omega-conotoxin peptide family, and illustrate how such a seemingly simple snail has yielded a highly effective clinical drug.
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Affiliation(s)
- Jon-Paul Bingham
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, HI 96822, USA.
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40
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Landgren S, Engel JA, Andersson ME, Gonzalez-Quintela A, Campos J, Nilsson S, Zetterberg H, Blennow K, Jerlhag E. Association of nAChR gene haplotypes with heavy alcohol use and body mass. Brain Res 2009; 1305 Suppl:S72-9. [DOI: 10.1016/j.brainres.2009.08.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 07/01/2009] [Accepted: 08/06/2009] [Indexed: 10/20/2022]
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41
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Dwoskin LP, Smith AM, Wooters TE, Zhang Z, Crooks PA, Bardo MT. Nicotinic receptor-based therapeutics and candidates for smoking cessation. Biochem Pharmacol 2009; 78:732-43. [PMID: 19523455 PMCID: PMC4110684 DOI: 10.1016/j.bcp.2009.06.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 05/29/2009] [Accepted: 06/01/2009] [Indexed: 12/29/2022]
Abstract
Tobacco dependence is the most preventable cause of death and is a chronic, relapsing disorder in which compulsive tobacco use persists despite known negative health consequences. All currently available cessation agents (nicotine, varenicline and bupropion) have limited efficacy and are associated with high relapse rates, revealing a need for more efficacious, alternative pharmacotherapies. The major alkaloid in tobacco, nicotine, activates nicotinic receptors (nAChRs) which increase brain extracellular dopamine producing nicotine reward leading to addiction. nAChRs are located primarily presynaptically and modulate synaptic activity by regulating neurotransmitter release. Subtype-selective nAChR antagonists that block reward-relevant mesocorticolimbic and nigrostriatal dopamine release induced by nicotine may offer advantages over current therapies. An innovative approach is to provide pharmacotherapies which are antagonists at nAChR subtypes mediating nicotine evoked dopamine release. In addition, providing multiple medications with a wider array of targets and mechanisms should provide more treatment options for individuals who are not responsive to the currently available pharmacotherapies. This review summarizes the currently available smoking cessation therapies and discusses emerging potential therapeutic approaches employing pharmacological agents which act as antagonists at nicotinic receptors.
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Affiliation(s)
- Linda P Dwoskin
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA.
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Peng C, Chen W, Han Y, Sanders T, Chew G, Liu J, Hawrot E, Chi C, Wang C. Characterization of a novel alpha4/4-conotoxin, Qc1.2, from vermivorous Conus quercinus. Acta Biochim Biophys Sin (Shanghai) 2009; 41:858-64. [PMID: 19779652 DOI: 10.1093/abbs/gmp077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
As part of continuing studies of the identification of gene organization and cloning of novel alpha-conotoxins, the first alpha4/4-conotoxin identified in a vermivorous Conus species, designated Qc1.2, was originally obtained by cDNA and genomic DNA cloning from Conus quercinus collected in the South China Sea. The predicted mature toxin of Qc1.2 contains 14 amino acid residues with two disulfide bonds (I-III, II-IV connectivity) in a native globular configuration. The mature peptide of Qc1.2 is supposed to contain an N-terminal post-translationally processed pyroglutamate residue and a free carboxyl C-terminus. This peptide was chemically synthesized and refolded for further characterization of its functional properties. The synthetic Qc1.2 has two interconvertible conformations in aqueous solution, which may be due to the cis-trans isomerization of the two successive Pro residues in its first Cys loop. Using the Xenopus oocyte heterologous expression system, Qc1.2 was shown to selectively inhibit both rat neuronal alpha3beta2 and alpha3beta4 subtypes of nicotinic acetylcholine receptors with low potency. A block of about 63% and 37% of the ACh-evoked currents was observed, respectively, and the toxin dissociated rapidly from the receptors. Compared with other characterized alpha-conotoxin members, the unusual structural features in Qc1.2 that confer to its receptor recognition profile are addressed.
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Affiliation(s)
- Can Peng
- Institute of Protein Research, Tongji University, Shanghai, China
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43
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Kauferstein S, Kendel Y, Nicke A, Coronas FIV, Possani LD, Favreau P, Krizaj I, Wunder C, Kauert G, Mebs D. New conopeptides of the D-superfamily selectively inhibiting neuronal nicotinic acetylcholine receptors. Toxicon 2009; 54:295-301. [PMID: 19393680 DOI: 10.1016/j.toxicon.2009.04.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 04/10/2009] [Accepted: 04/14/2009] [Indexed: 11/26/2022]
Abstract
The venom of cone snails (Conus spp.) is a rich source of peptides exhibiting a wide variety of biological activities. Several of these conopeptides are neuronal nicotinic acetylcholine receptor (nAChR) antagonists and belong to the A-, M-, S-, C and the recently described D-superfamily (alphaD-conopeptides). Here we describe the discovery and characterization of two alphaD-conopeptides isolated from the venom of Conus mustelinus and Conus capitaneus. Their primary structure was determined by Edman degradation, MS/MS analysis and by a PCR based approach. These peptides show close structural homology to the alphaD-VxXIIA, -B and -C conopeptides from the venom of Conus vexillum and are dimers (about 11kDa) of similar or identical peptides with 49 amino acid residues and a characteristic arrangement of ten conserved cysteine residues. These novel types of conopeptides specifically block neuronal nAChRs of the alpha7, alpha3beta2 and alpha4beta2 subtypes in nanomolar concentrations. Due to their high affinity, these new ligands may provide a tool to decipher the localisation and function of the various neuronal nAChRs.
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Affiliation(s)
- S Kauferstein
- Zentrum der Rechtsmedizin, University of Frankfurt, Kennedyallee 104, D-60596 Frankfurt, Germany.
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Loughnan ML, Nicke A, Lawrence N, Lewis RJ. Novel αD-Conopeptides and Their Precursors Identified by cDNA Cloning Define the D-Conotoxin Superfamily. Biochemistry 2009; 48:3717-29. [DOI: 10.1021/bi9000326] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Marion L. Loughnan
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
| | - Annette Nicke
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
| | - Nicole Lawrence
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
| | - Richard J. Lewis
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia, and Max Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt/Main, Germany
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45
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Conotoxins: molecular and therapeutic targets. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2009; 46:45-65. [PMID: 19184584 DOI: 10.1007/978-3-540-87895-7_2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Marine molluscs known as cone snails produce beautiful shells and a complex array of over 50,000 venom peptides evolved for prey capture and defence. Many of these peptides selectively modulate ion channels and transporters, making them a valuable source of new ligands for studying the role these targets play in normal and disease physiology. A number of conopeptides reduce pain in animal models, and several are now in pre-clinical and clinical development for the treatment of severe pain often associated with diseases such as cancer. Less than 1% of cone snail venom peptides are pharmacologically characterised.
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46
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Conotoxin Venom Peptide Therapeutics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 655:44-8. [DOI: 10.1007/978-1-4419-1132-2_5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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47
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Peng C, Han Y, Sanders T, Chew G, Liu J, Hawrot E, Chi C, Wang C. alpha4/7-conotoxin Lp1.1 is a novel antagonist of neuronal nicotinic acetylcholine receptors. Peptides 2008; 29:1700-7. [PMID: 18588930 PMCID: PMC4826758 DOI: 10.1016/j.peptides.2008.05.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 05/26/2008] [Accepted: 05/27/2008] [Indexed: 11/18/2022]
Abstract
Cone snails comprise approximately 700 species of venomous molluscs which have evolved the ability to generate multiple toxins with varied and exquisite selectivity. alpha-Conotoxin is a powerful tool for defining the composition and function of nicotinic acetylcholine receptors which play a crucial role in excitatory neurotransmission and are important targets for drugs and insecticides. An alpha4/7 conotoxin, Lp1.1, originally identified by cDNA and genomic DNA cloning from Conus leopardus, was found devoid of the highly conserved Pro residue in the first intercysteine loop. To further study this toxin, alpha-Lp1.1 was chemically synthesized and refolded into its globular disulfide isomer. The synthetic Lp1.1 induced seizure and paralysis on freshwater goldfish and selectively reversibly inhibited ACh-evoked currents in Xenopus oocytes expressing rat alpha3beta2 and alpha6alpha3beta2 nAChRs. Comparing the distinct primary structure with other functionally related alpha-conotoxins could indicate structural features in Lp1.1 that may be associated with its unique receptor recognition profile.
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Affiliation(s)
- Can Peng
- Institute of Protein Research, Tongji University, Shanghai 200092, China
| | - Yuhong Han
- Institute of Protein Research, Tongji University, Shanghai 200092, China
| | - Tanya Sanders
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
| | - Geoffrey Chew
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
| | - Jing Liu
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
| | - Edward Hawrot
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown Medical School, Providence, Rhode Island 02912, USA
| | - Chengwu Chi
- Institute of Protein Research, Tongji University, Shanghai 200092, China
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chunguang Wang
- Institute of Protein Research, Tongji University, Shanghai 200092, China
- Corresponding author and address: Chunguang Wang, Institute of Protein Research, Tongji University 1239 Siping Road, Shanghai 200092, China Tel.: +86-21-65984347 Fax: +86-21-65988403
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48
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Exley R, Clements MA, Hartung H, McIntosh JM, Cragg SJ. Alpha6-containing nicotinic acetylcholine receptors dominate the nicotine control of dopamine neurotransmission in nucleus accumbens. Neuropsychopharmacology 2008; 33:2158-66. [PMID: 18033235 DOI: 10.1038/sj.npp.1301617] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Modulation of striatal dopamine (DA) neurotransmission plays a fundamental role in the reinforcing and ultimately addictive effects of nicotine. Nicotine, by desensitizing beta2 subunit-containing (beta2*) nicotinic acetylcholine receptors (nAChRs) on striatal DA axons, significantly enhances how DA is released by reward-related burst activity compared to nonreward-related tonic activity. This action provides a synaptic mechanism for nicotine to facilitate the DA-dependent reinforcement. The subfamily of beta2*-nAChRs responsible for these potent synaptic effects could offer a molecular target for therapeutic strategies in nicotine addiction. We explored the role of alpha6beta2*-nAChRs in the nucleus accumbens (NAc) and caudate-putamen (CPu) by observing action potential-dependent DA release from synapses in real-time using fast-scan cyclic voltammetry at carbon-fiber microelectrodes in mouse striatal slices. The alpha6-specific antagonist alpha-conotoxin-MII suppressed DA release evoked by single and low-frequency action potentials and concurrently enhanced release by high-frequency bursts in a manner similar to the beta2*-selective antagonist dihydro-beta-erythroidine (DHbetaE) in NAc, but less so in CPu. The greater role for alpha6*-nAChRs in NAc was not due to any confounding regional difference in ACh tone since elevated ACh levels (after the acetylcholinesterase inhibitor ambenonium) had similar outcomes in NAc and CPu. Rather, there appear to be underlying differences in nAChR subtype function in NAc and CPu. In summary, we reveal that alpha6beta2*-nAChRs dominate the effects of nicotine on DA release in NAc, whereas in CPu their role is minor alongside other beta2*-nAChRs (eg alpha4*), These data offer new insights to suggest striatal alpha6*-nAChRs as a molecular target for a therapeutic strategy for nicotine addiction.
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Affiliation(s)
- Richard Exley
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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Innocent N, Livingstone PD, Hone A, Kimura A, Young T, Whiteaker P, McIntosh JM, Wonnacott S. Alpha-conotoxin Arenatus IB[V11L,V16D] [corrected] is a potent and selective antagonist at rat and human native alpha7 nicotinic acetylcholine receptors. J Pharmacol Exp Ther 2008; 327:529-37. [PMID: 18664588 DOI: 10.1124/jpet.108.142943] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A recently developed alpha-conotoxin, alpha-conotoxin Arenatus IB-[V11L,V16D] (alpha-CtxArIB[V11L,V16D]) [corrected], is a potent and selective competitive antagonist at rat recombinant alpha7 nicotinic acetylcholine receptors (nAChRs), making it an attractive probe for this receptor subtype. alpha7 nAChRs are potential therapeutic targets that are widely expressed in both neuronal and non-neuronal tissues, where they are implicated in a variety of functions. In this study, we evaluate this toxin at rat and human native nAChRs. Functional alpha7 nAChR responses were evoked by choline plus the allosteric potentiator PNU-120596 [1-(5-chloro-2,4-dimethoxy-phenyl)-3-(5-methyl-isoxazol-3-yl)-urea] in rat PC12 cells and human SH-SY5Y cells loaded with calcium indicators. alpha-CtxArIB[V11L,V16D] specifically inhibited alpha7 nAChR-mediated increases in Ca2+ in PC12 cells. Responses to other stimuli, 5-I-A-85380 [5-iodo-3-(2(S)-azetidinylmethoxy)pyridine dihydrochloride], nicotine, or KCl, that did not activate alpha7 nAChRs were unaffected. Human alpha7 nAChRs were also sensitive to alpha-CtxArIB[V11L, V16D]; acetylcholine-evoked currents in Xenopus laevis oocytes expressing human alpha7 nAChRs were inhibited by alpha-CtxArIB[V11L,V16D] (IC(50), 3.4 nM) in a slowly reversible manner, with full recovery taking 15 min. This is consistent with the time course of recovery from blockade of rat alpha7 nAChRs in PC12 cells. alpha-CtxArIB[V11L,V16D] inhibited human native alpha7 nAChRs in SHSY5Y cells, activated by either choline or AR-R17779 [(2)-spiro[1-azabicyclo[2.2.2]octane-3,59-oxazolidin]-29-one] plus PNU-120596. Rat brain alpha7 nAChRs contribute to dopamine release from striatal minces; alpha-CtxArIB[V11L,V16D] (300 nM) selectively inhibited choline-evoked dopamine release without affecting responses evoked by nicotine that activates heteromeric nAChRs. This study establishes that alpha-CtxArIB[V11L,V16D] selectively inhibits human and rat native alpha7 nAChRs with comparable potency, making this a potentially useful antagonist for investigating alpha7 nAChR functions.
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Affiliation(s)
- Neal Innocent
- Department of Biology and Biochemistry, University of Bath, Bath BA27AY, UK
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50
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Hogg RC, Bertrand D. Neurotoxins acting at nicotinic receptors. FUTURE NEUROLOGY 2008. [DOI: 10.2217/14796708.3.4.463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neurotoxins include, in the most general sense, all molecules that destroy or inhibit the proper functioning of the nervous system. Neurotoxins from animals and plants include alkaloids and peptides, many of which interact with physiological processes in a selective manner. The majority of neurotoxins disrupt the transmission of signals in the nervous system by interfering with synaptic transmission. Neurotoxins can act presynaptically to inhibit the release, uptake and recycling of neurotransmitters or postsynaptically, binding to receptors on the postsynaptic membrane and preventing their activation by neurotransmitters. A class of neurotoxins from plants and animals interact with nicotinic acetylcholine receptors, either at the neuromuscular junction, peripherally at neuronal ganglia or centrally, to produce neurotoxic effects. In this article we review current knowledge of some of these neurotoxins, their structure, pharmacology, importance as pharmaceutical tools as well as future prospects for the development of therapeutic molecules.
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Affiliation(s)
- Ron C Hogg
- University of Geneva, Department of Neurosciences Fondamentales, Faculty of Medicine, 1, rue Michel Servet, CH-1211 Geneva 4, Switzerland
| | - Daniel Bertrand
- University of Geneva, Department of Neurosciences Fondamentales, Faculty of Medicine, Switzerland
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