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Pei S, Wang N, Mei Z, Zhangsun D, Craik DJ, McIntosh JM, Zhu X, Luo S. Conotoxins Targeting Voltage-Gated Sodium Ion Channels. Pharmacol Rev 2024; 76:828-845. [PMID: 38914468 PMCID: PMC11331937 DOI: 10.1124/pharmrev.123.000923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 06/17/2024] [Accepted: 06/18/2024] [Indexed: 06/26/2024] Open
Abstract
Voltage-gated sodium (NaV) channels are intimately involved in the generation and transmission of action potentials, and dysfunction of these channels may contribute to nervous system diseases, such as epilepsy, neuropathic pain, psychosis, autism, and cardiac arrhythmia. Many venom peptides selectively act on NaV channels. These include conotoxins, which are neurotoxins secreted by cone snails for prey capture or self-defense but which are also valuable pharmacological tools for the identification and/or treatment of human diseases. Typically, conotoxins contain two or three disulfide bonds, and these internal crossbraces contribute to conotoxins having compact, well defined structures and high stability. Of the conotoxins containing three disulfide bonds, some selectively target mammalian NaV channels and can block, stimulate, or modulate these channels. Such conotoxins have great potential to serve as pharmacological tools for studying the functions and characteristics of NaV channels or as drug leads for neurologic diseases related to NaV channels. Accordingly, discovering or designing conotoxins targeting NaV channels with high potency and selectivity is important. The amino acid sequences, disulfide bond connectivity, and three-dimensional structures are key factors that affect the biological activity of conotoxins, and targeted synthetic modifications of conotoxins can greatly improve their activity and selectivity. This review examines NaV channel-targeted conotoxins, focusing on their structures, activities, and designed modifications, with a view toward expanding their applications. SIGNIFICANCE STATEMENT: NaV channels are crucial in various neurologic diseases. Some conotoxins selectively target NaV channels, causing either blockade or activation, thus enabling their use as pharmacological tools for studying the channels' characteristics and functions. Conotoxins also have promising potential to be developed as drug leads. The disulfide bonds in these peptides are important for stabilizing their structures, thus leading to enhanced specificity and potency. Together, conotoxins targeting NaV channels have both immediate research value and promising future application prospects.
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Affiliation(s)
- Shengrong Pei
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Nan Wang
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Zaoli Mei
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Dongting Zhangsun
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - David J Craik
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - J Michael McIntosh
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Xiaopeng Zhu
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
| | - Sulan Luo
- Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning, China (S.P., N.W., Z.M., D.Z., X.Z., S.L.); Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou, China (D.Z., S.L.); Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia (D.J.C.); Departments of Biology and Psychiatry, University of Utah, Salt Lake City, Utah (J.M.M.); and George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, Utah (J.M.M.)
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McMahon KL, Vetter I, Schroeder CI. Voltage-Gated Sodium Channel Inhibition by µ-Conotoxins. Toxins (Basel) 2024; 16:55. [PMID: 38251271 PMCID: PMC10819908 DOI: 10.3390/toxins16010055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/23/2024] Open
Abstract
µ-Conotoxins are small, potent pore-blocker inhibitors of voltage-gated sodium (NaV) channels, which have been identified as pharmacological probes and putative leads for analgesic development. A limiting factor in their therapeutic development has been their promiscuity for different NaV channel subtypes, which can lead to undesirable side-effects. This review will focus on four areas of µ-conotoxin research: (1) mapping the interactions of µ-conotoxins with different NaV channel subtypes, (2) µ-conotoxin structure-activity relationship studies, (3) observed species selectivity of µ-conotoxins and (4) the effects of µ-conotoxin disulfide connectivity on activity. Our aim is to provide a clear overview of the current status of µ-conotoxin research.
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Affiliation(s)
- Kirsten L. McMahon
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Irina Vetter
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- The School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Christina I. Schroeder
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia
- Genentech, 1 DNA Way, South San Francisco, CA 94080, USA
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3
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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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4
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McMahon KL, Tran HNT, Deuis JR, Craik DJ, Vetter I, Schroeder CI. µ-Conotoxins Targeting the Human Voltage-Gated Sodium Channel Subtype NaV1.7. Toxins (Basel) 2022; 14:toxins14090600. [PMID: 36136538 PMCID: PMC9506549 DOI: 10.3390/toxins14090600] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 12/03/2022] Open
Abstract
µ-Conotoxins are small, potent, peptide voltage-gated sodium (NaV) channel inhibitors characterised by a conserved cysteine framework. Despite promising in vivo studies indicating analgesic potential of these compounds, selectivity towards the therapeutically relevant subtype NaV1.7 has so far been limited. We recently identified a novel µ-conotoxin, SxIIIC, which potently inhibits human NaV1.7 (hNaV1.7). SxIIIC has high sequence homology with other µ-conotoxins, including SmIIIA and KIIIA, yet shows different NaV channel selectivity for mammalian subtypes. Here, we evaluated and compared the inhibitory potency of µ-conotoxins SxIIIC, SmIIIA and KIIIA at hNaV channels by whole-cell patch-clamp electrophysiology and discovered that these three closely related µ-conotoxins display unique selectivity profiles with significant variations in inhibitory potency at hNaV1.7. Analysis of other µ-conotoxins at hNaV1.7 shows that only a limited number are capable of inhibition at this subtype and that differences between the number of residues in loop 3 appear to influence the ability of µ-conotoxins to inhibit hNaV1.7. Through mutagenesis studies, we confirmed that charged residues in this region also affect the selectivity for hNaV1.4. Comparison of µ-conotoxin NMR solution structures identified differences that may contribute to the variance in hNaV1.7 inhibition and validated the role of the loop 1 extension in SxIIIC for improving potency at hNaV1.7, when compared to KIIIA. This work could assist in designing µ-conotoxin derivatives specific for hNaV1.7.
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Affiliation(s)
- Kirsten L. McMahon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Hue N. T. Tran
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jennifer R. Deuis
- 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
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- The School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
- Correspondence: (I.V.); (C.I.S.)
| | - Christina I. Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
- Correspondence: (I.V.); (C.I.S.)
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5
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Voltage-Gated Sodium Channels: A Prominent Target of Marine Toxins. Mar Drugs 2021; 19:md19100562. [PMID: 34677461 PMCID: PMC8537899 DOI: 10.3390/md19100562] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/29/2021] [Accepted: 10/02/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are considered to be one of the most important ion channels given their remarkable physiological role. VGSCs constitute a family of large transmembrane proteins that allow transmission, generation, and propagation of action potentials. This occurs by conducting Na+ ions through the membrane, supporting cell excitability and communication signals in various systems. As a result, a wide range of coordination and physiological functions, from locomotion to cognition, can be accomplished. Drugs that target and alter the molecular mechanism of VGSCs’ function have highly contributed to the discovery and perception of the function and the structure of this channel. Among those drugs are various marine toxins produced by harmful microorganisms or venomous animals. These toxins have played a key role in understanding the mode of action of VGSCs and in mapping their various allosteric binding sites. Furthermore, marine toxins appear to be an emerging source of therapeutic tools that can relieve pain or treat VGSC-related human channelopathies. Several studies documented the effect of marine toxins on VGSCs as well as their pharmaceutical applications, but none of them underlined the principal marine toxins and their effect on VGSCs. Therefore, this review aims to highlight the neurotoxins produced by marine animals such as pufferfish, shellfish, sea anemone, and cone snail that are active on VGSCs and discuss their pharmaceutical values.
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McMahon KL, Tran HN, Deuis JR, Lewis RJ, Vetter I, Schroeder CI. Discovery, Pharmacological Characterisation and NMR Structure of the Novel µ-Conotoxin SxIIIC, a Potent and Irreversible Na V Channel Inhibitor. Biomedicines 2020; 8:biomedicines8100391. [PMID: 33023152 PMCID: PMC7599555 DOI: 10.3390/biomedicines8100391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (NaV) channel subtypes, including NaV1.7, are promising targets for the treatment of neurological diseases, such as chronic pain. Cone snail-derived µ-conotoxins are small, potent NaV channel inhibitors which represent potential drug leads. Of the 22 µ-conotoxins characterised so far, only a small number, including KIIIA and CnIIIC, have shown inhibition against human NaV1.7. We have recently identified a novel µ-conotoxin, SxIIIC, from Conus striolatus. Here we present the isolation of native peptide, chemical synthesis, characterisation of human NaV channel activity by whole-cell patch-clamp electrophysiology and analysis of the NMR solution structure. SxIIIC displays a unique NaV channel selectivity profile (1.4 > 1.3 > 1.1 ≈ 1.6 ≈ 1.7 > 1.2 >> 1.5 ≈ 1.8) when compared to other µ-conotoxins and represents one of the most potent human NaV1.7 putative pore blockers (IC50 152.2 ± 21.8 nM) to date. NMR analysis reveals the structure of SxIIIC includes the characteristic α-helix seen in other µ-conotoxins. Future investigations into structure-activity relationships of SxIIIC are expected to provide insights into residues important for NaV channel pore blocker selectivity and subsequently important for chronic pain drug development.
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Affiliation(s)
- Kirsten L. McMahon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Hue N.T. Tran
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Richard J. Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
- The School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
- Correspondence: (I.V.); (C.I.S.)
| | - Christina I. Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia; (K.L.M.); (H.N.T.T.); (J.R.D.); (R.J.L.)
- National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
- Correspondence: (I.V.); (C.I.S.)
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7
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Gallo A, Boni R, Tosti E. Neurobiological activity of conotoxins via sodium channel modulation. Toxicon 2020; 187:47-56. [PMID: 32877656 DOI: 10.1016/j.toxicon.2020.08.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/20/2020] [Accepted: 08/22/2020] [Indexed: 01/02/2023]
Abstract
Conotoxins (CnTX) are bioactive peptides produced by marine molluscs belonging to Conus genus. The biochemical structure of these venomous peptides is characterized by a low number of amino acids linked with disulfide bonds formed by a high degree of post-translational modifications and glycosylation steps which increase the diversity and rate of evolution of these molecules. CnTX different isoforms are known to target ion channels and, in particular, voltage-gated sodium (Na+) channels (Nav channels). These are transmembrane proteins fundamental in excitable cells for generating the depolarization of plasma membrane potential known as action potential which propagates electrical signals in muscles and nerves for physiological functions. Disorders in Nav channel activity have been shown to induce neurological pathologies and pain states. Here, we describe the current knowledge of CnTX isoform modulation of the Nav channel activity, the mechanism of action and the potential therapeutic use of these toxins in counteracting neurological dysfunctions.
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Affiliation(s)
- Alessandra Gallo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
| | - Raffele Boni
- Department of Sciences, University of Basilicata, 85100, Potenza, Italy.
| | - Elisabetta Tosti
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy.
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8
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In Silico Analysis of the Subtype Selective Blockage of KCNA Ion Channels through the µ-Conotoxins PIIIA, SIIIA, and GIIIA. Mar Drugs 2019; 17:md17030180. [PMID: 30893914 PMCID: PMC6471588 DOI: 10.3390/md17030180] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/12/2019] [Accepted: 03/15/2019] [Indexed: 12/12/2022] Open
Abstract
Understanding subtype specific ion channel pore blockage by natural peptide-based toxins is crucial for developing such compounds into promising drug candidates. Herein, docking and molecular dynamics simulations were employed in order to understand the dynamics and binding states of the µ-conotoxins, PIIIA, SIIIA, and GIIIA, at the voltage-gated potassium channels of the KV1 family, and they were correlated with their experimental activities recently reported by Leipold et al. Their different activities can only adequately be understood when dynamic information about the toxin-channel systems is available. For all of the channel-bound toxins investigated herein, a certain conformational flexibility was observed during the molecular dynamic simulations, which corresponds to their bioactivity. Our data suggest a similar binding mode of µ-PIIIA at KV1.6 and KV1.1, in which a plethora of hydrogen bonds are formed by the Arg and Lys residues within the α-helical core region of µ-PIIIA, with the central pore residues of the channel. Furthermore, the contribution of the K+ channel’s outer and inner pore loops with respect to the toxin binding. and how the subtype specificity is induced, were proposed.
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Peigneur S, Cheneval O, Maiti M, Leipold E, Heinemann SH, Lescrinier E, Herdewijn P, De Lima ME, Craik DJ, Schroeder CI, Tytgat J. Where cone snails and spiders meet: design of small cyclic sodium-channel inhibitors. FASEB J 2018; 33:3693-3703. [PMID: 30509130 DOI: 10.1096/fj.201801909r] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A 13 aa residue voltage-gated sodium (NaV) channel inhibitor peptide, Pn, containing 2 disulfide bridges was designed by using a chimeric approach. This approach was based on a common pharmacophore deduced from sequence and secondary structural homology of 2 NaV inhibitors: Conus kinoshitai toxin IIIA, a 14 residue cone snail peptide with 3 disulfide bonds, and Phoneutria nigriventer toxin 1, a 78 residue spider toxin with 7 disulfide bonds. As with the parent peptides, this novel NaV channel inhibitor was active on NaV1.2. Through the generation of 3 series of peptide mutants, we investigated the role of key residues and cyclization and their influence on NaV inhibition and subtype selectivity. Cyclic PnCS1, a 10 residue peptide cyclized via a disulfide bond, exhibited increased inhibitory activity toward therapeutically relevant NaV channel subtypes, including NaV1.7 and NaV1.9, while displaying remarkable serum stability. These peptides represent the first and the smallest cyclic peptide NaV modulators to date and are promising templates for the development of toxin-based therapeutic agents.-Peigneur, S., Cheneval, O., Maiti, M., Leipold, E., Heinemann, S. H., Lescrinier, E., Herdewijn, P., De Lima, M. E., Craik, D. J., Schroeder, C. I., Tytgat, J. Where cone snails and spiders meet: design of small cyclic sodium-channel inhibitors.
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Affiliation(s)
- Steve Peigneur
- Toxicology and Pharmacology, Katholieke Universiteit (KU) Leuven, Campus Gasthuisberg, Leuven, Belgium.,Department de Bioquímica e Imunologia, Laboratório de Venenos e Toxinas Animais, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo-Horizonte, Brazil
| | - Olivier Cheneval
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Mohitosh Maiti
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Enrico Leipold
- Department of Biophysics, Center for Molecular Biomedicine, Jena University Hospital, Friedrich Schiller University Jena, Germany
| | - Stefan H Heinemann
- Department of Biophysics, Center for Molecular Biomedicine, Jena University Hospital, Friedrich Schiller University Jena, Germany
| | - Eveline Lescrinier
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Piet Herdewijn
- Laboratory of Medicinal Chemistry, Rega Institute for Medical Research, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Maria Elena De Lima
- Department de Bioquímica e Imunologia, Laboratório de Venenos e Toxinas Animais, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo-Horizonte, Brazil.,Programa de Pós-Graduação em Ciências da Saúde, Biomedicina e Medicina, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Grupo Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Christina I Schroeder
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Jan Tytgat
- Toxicology and Pharmacology, Katholieke Universiteit (KU) Leuven, Campus Gasthuisberg, Leuven, Belgium
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10
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Paul George AA, Heimer P, Maaß A, Hamaekers J, Hofmann-Apitius M, Biswas A, Imhof D. Insights into the Folding of Disulfide-Rich μ-Conotoxins. ACS OMEGA 2018; 3:12330-12340. [PMID: 30411002 PMCID: PMC6217517 DOI: 10.1021/acsomega.8b01465] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
The study of protein conformations using molecular dynamics (MD) simulations has been in place for decades. A major contribution to the structural stability and native conformation of a protein is made by the primary sequence and disulfide bonds formed during the folding process. Here, we investigated μ-conotoxins GIIIA, KIIIA, PIIIA, SIIIA, and SmIIIA as model peptides possessing three disulfide bonds. Their NMR structures were used for MD simulations in a novel approach studying the conformations between the folded and the unfolded states by systematically breaking the distinct disulfide bonds and monitoring the conformational stability of the peptides. As an outcome, the use of a combination of the existing knowledge and results from the simulations to classify the studied peptides within the extreme models of disulfide folding pathways, namely the bovine pancreatic trypsin inhibitor pathway and the hirudin pathway, is demonstrated. Recommendations for the design and synthesis of cysteine-rich peptides with a reduced number of disulfide bonds conclude the study.
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Affiliation(s)
- Ajay Abisheck Paul George
- Pharmaceutical
Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Pascal Heimer
- Pharmaceutical
Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Astrid Maaß
- Department
of Virtual Material Design and Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific
Computing, Schloss Birlinghoven, D-53754 Sankt Augustin, Germany
| | - Jan Hamaekers
- Department
of Virtual Material Design and Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific
Computing, Schloss Birlinghoven, D-53754 Sankt Augustin, Germany
| | - Martin Hofmann-Apitius
- Department
of Virtual Material Design and Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific
Computing, Schloss Birlinghoven, D-53754 Sankt Augustin, Germany
- Bonn-Aachen
International Center for Information Technology, University of Bonn, Endenicher Allee 19 C, D-53115 Bonn, Germany
| | - Arijit Biswas
- Institute
for Experimental Hematology, University
Hospital Bonn, Sigmund-Freud-Straße
25, D-53127 Bonn, Germany
| | - Diana Imhof
- Pharmaceutical
Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
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A novel μ-conotoxin from worm-hunting Conus tessulatus that selectively inhibit rat TTX-resistant sodium currents. Toxicon 2017; 130:11-18. [DOI: 10.1016/j.toxicon.2017.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 02/01/2017] [Accepted: 02/16/2017] [Indexed: 12/13/2022]
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12
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Leipold E, Ullrich F, Thiele M, Tietze AA, Terlau H, Imhof D, Heinemann SH. Subtype-specific block of voltage-gated K+ channels by μ-conopeptides. Biochem Biophys Res Commun 2017; 482:1135-1140. [DOI: 10.1016/j.bbrc.2016.11.170] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 11/30/2016] [Indexed: 12/19/2022]
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13
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Han P, Wang K, Dai X, Cao Y, Liu S, Jiang H, Fan C, Wu W, Chen J. The Role of Individual Disulfide Bonds of μ-Conotoxin GIIIA in the Inhibition of Na V1.4. Mar Drugs 2016; 14:md14110213. [PMID: 27869701 PMCID: PMC5128756 DOI: 10.3390/md14110213] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 10/31/2016] [Accepted: 11/11/2016] [Indexed: 12/20/2022] Open
Abstract
μ-Conotoxin GIIIA, a peptide toxin isolated from Conus geographus, preferentially blocks the skeletal muscle sodium channel NaV1.4. GIIIA folds compactly to a pyramidal structure stabilized by three disulfide bonds. To assess the contributions of individual disulfide bonds of GIIIA to the blockade of NaV1.4, seven disulfide-deficient analogues were prepared and characterized, each with one, two, or three pairs of disulfide-bonded Cys residues replaced with Ala. The inhibitory potency of the analogues against NaV1.4 was assayed by whole cell patch-clamp on rNaV1.4, heterologously expressed in HEK293 cells. The corresponding IC50 values were 0.069 ± 0.005 μM for GIIIA, 2.1 ± 0.3 μM for GIIIA-1, 3.3 ± 0.2 μM for GIIIA-2, and 15.8 ± 0.8 μM for GIIIA-3 (-1, -2 and -3 represent the removal of disulfide bridges Cys3–Cys15, Cys4–Cys20 and Cys10–Cys21, respectively). Other analogues were not active enough for IC50 measurement. Our results indicate that all three disulfide bonds of GIIIA are required to produce effective inhibition of NaV1.4, and the removal of any one significantly lowers its sodium channel binding affinity. Cys10–Cys21 is the most important for the NaV1.4 potency.
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Affiliation(s)
- Penggang Han
- College of Science, National University of Defense Technology, Changsha 410073, Hunan, China.
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Kang Wang
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Xiandong Dai
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Ying Cao
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Shangyi Liu
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Hui Jiang
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Chongxu Fan
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
| | - Wenjian Wu
- College of Science, National University of Defense Technology, Changsha 410073, Hunan, China.
| | - Jisheng Chen
- College of Science, National University of Defense Technology, Changsha 410073, Hunan, China.
- Beijing Institute of Pharmaceutical Chemistry, Beijing 102205, China.
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Ahern CA, Payandeh J, Bosmans F, Chanda B. The hitchhiker's guide to the voltage-gated sodium channel galaxy. ACTA ACUST UNITED AC 2016; 147:1-24. [PMID: 26712848 PMCID: PMC4692491 DOI: 10.1085/jgp.201511492] [Citation(s) in RCA: 234] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Eukaryotic voltage-gated sodium (Nav) channels contribute to the rising phase of action potentials and served as an early muse for biophysicists laying the foundation for our current understanding of electrical signaling. Given their central role in electrical excitability, it is not surprising that (a) inherited mutations in genes encoding for Nav channels and their accessory subunits have been linked to excitability disorders in brain, muscle, and heart; and (b) Nav channels are targeted by various drugs and naturally occurring toxins. Although the overall architecture and behavior of these channels are likely to be similar to the more well-studied voltage-gated potassium channels, eukaryotic Nav channels lack structural and functional symmetry, a notable difference that has implications for gating and selectivity. Activation of voltage-sensing modules of the first three domains in Nav channels is sufficient to open the channel pore, whereas movement of the domain IV voltage sensor is correlated with inactivation. Also, structure–function studies of eukaryotic Nav channels show that a set of amino acids in the selectivity filter, referred to as DEKA locus, is essential for Na+ selectivity. Structures of prokaryotic Nav channels have also shed new light on mechanisms of drug block. These structures exhibit lateral fenestrations that are large enough to allow drugs or lipophilic molecules to gain access into the inner vestibule, suggesting that this might be the passage for drug entry into a closed channel. In this Review, we will synthesize our current understanding of Nav channel gating mechanisms, ion selectivity and permeation, and modulation by therapeutics and toxins in light of the new structures of the prokaryotic Nav channels that, for the time being, serve as structural models of their eukaryotic counterparts.
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Affiliation(s)
- Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242
| | - Jian Payandeh
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA 94080
| | - Frank Bosmans
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205 Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Baron Chanda
- Department of Neuroscience and Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705 Department of Neuroscience and Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705
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15
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Heterologous expression of NaV1.9 chimeras in various cell systems. Pflugers Arch 2015; 467:2423-35. [PMID: 25916202 DOI: 10.1007/s00424-015-1709-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/31/2015] [Accepted: 04/16/2015] [Indexed: 01/27/2023]
Abstract
SCN11A encodes the voltage-gated sodium channel NaV1.9, which deviates most strongly from the other eight NaV channels expressed in mammals. It is characterized by resistance to the prototypic NaV channel blocker tetrodotoxin and exhibits slow activation and inactivation gating. Its expression in dorsal root ganglia neurons suggests a role in motor or pain signaling functions as also recently demonstrated by the occurrence of various mutations in human SCN11A leading to altered pain sensation syndromes. The systematic investigation of human NaV1.9, however, is severely hampered because of very poor heterologous expression in host cells. Using patch-clamp and two-electrode voltage-clamp methods, we show that this limitation is caused by the C-terminal structure of NaV1.9. A chimera of NaV1.9 harboring the C terminus of NaV1.4 yields functional expression not only in neuronal cells but also in non-excitable cells, such as HEK 293T or Xenopus oocytes. The major functional difference of the chimeric channel with respect to NaV1.9 is an accelerated activation and inactivation. Since the entire transmembrane domain is preserved, it is suited for studying pharmacological properties of the channel and the functional impact of disease-causing mutations. Moreover, we demonstrate how mutation S360Y makes NaV1.9 channels sensitive to tetrodotoxin and saxitoxin and that the unusual slow open-state inactivation of NaV1.9 is also mediated by the IFM (isoleucine-phenylalanine-methionine) inactivation motif located in the linker connecting domains III and IV.
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16
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Wilson MJ, Zhang MM, Gajewiak J, Azam L, Rivier JE, Olivera BM, Yoshikami D. Α- and β-subunit composition of voltage-gated sodium channels investigated with μ-conotoxins and the recently discovered μO§-conotoxin GVIIJ. J Neurophysiol 2015; 113:2289-301. [PMID: 25632083 DOI: 10.1152/jn.01004.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 01/26/2015] [Indexed: 11/22/2022] Open
Abstract
We investigated the identities of the isoforms of the α (NaV1)- and β (NaVβ)-subunits of voltage-gated sodium channels, including those responsible for action potentials in rodent sciatic nerves. To examine α-subunits, we used seven μ-conotoxins, which target site 1 of the channel. With the use of exogenously expressed channels, we show that two of the μ-conotoxins, μ-BuIIIB and μ-SxIIIA, are 50-fold more potent in blocking NaV1.6 from mouse than that from rat. Furthermore, we observed that μ-BuIIIB and μ-SxIIIA are potent blockers of large, myelinated A-fiber compound action potentials (A-CAPs) [but not small, unmyelinated C-fiber CAPs (C-CAPs)] in the sciatic nerve of the mouse (unlike A-CAPs of the rat, previously shown to be insensitive to these toxins). To investigate β-subunits, we used two synthetic derivatives of the recently discovered μO§-conotoxin GVIIJ that define site 8 of the channel, as previously characterized with cloned rat NaV1- and NaVβ-subunits expressed in Xenopus laevis oocytes, where it was shown that μO§-GVIIJ is a potent inhibitor of several NaV1-isoforms and that coexpression of NaVβ2 or -β4 (but not NaVβ1 or -β3) totally protects against block by μO§-GVIIJ. We report here the effects of μO§-GVIIJ on 1) sodium currents of mouse NaV1.6 coexpressed with various combinations of NaVβ-subunits in oocytes; 2) A- and C-CAPs of mouse and rat sciatic nerves; and 3) sodium currents of small and large neurons dissociated from rat dorsal root ganglia. Our overall results lead us to conclude that action potentials in A-fibers of the rodent sciatic nerve are mediated primarily by NaV1.6 associated with NaVβ2 or NaVβ4.
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Affiliation(s)
- Michael J Wilson
- Department of Biology, University of Utah, Salt Lake City, Utah; and
| | - Min-Min Zhang
- Department of Biology, University of Utah, Salt Lake City, Utah; and
| | - Joanna Gajewiak
- Department of Biology, University of Utah, Salt Lake City, Utah; and
| | - Layla Azam
- Department of Biology, University of Utah, Salt Lake City, Utah; and
| | - Jean E Rivier
- The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, California
| | | | - Doju Yoshikami
- Department of Biology, University of Utah, Salt Lake City, Utah; and
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17
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Zhang MM, Wilson MJ, Gajewiak J, Rivier JE, Bulaj G, Olivera BM, Yoshikami D. Pharmacological fractionation of tetrodotoxin-sensitive sodium currents in rat dorsal root ganglion neurons by μ-conotoxins. Br J Pharmacol 2014; 169:102-14. [PMID: 23351163 DOI: 10.1111/bph.12119] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/18/2012] [Accepted: 12/27/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Adult rat dorsal root ganglion (DRG) neurons normally express transcripts for five isoforms of the α-subunit of voltage-gated sodium channels: NaV 1.1, 1.6, 1.7, 1.8 and 1.9. Tetrodotoxin (TTX) readily blocks all but NaV 1.8 and 1.9, and pharmacological agents that discriminate among the TTX-sensitive NaV 1-isoforms are scarce. Recently, we used the activity profile of a panel of μ-conotoxins in blocking cloned rodent NaV 1-isoforms expressed in Xenopus laevis oocytes to conclude that action potentials of A- and C-fibres in rat sciatic nerve were, respectively, mediated primarily by NaV 1.6 and NaV 1.7. EXPERIMENTAL APPROACH We used three μ-conotoxins, μ-TIIIA, μ-PIIIA and μ-SmIIIA, applied individually and in combinations, to pharmacologically differentiate the TTX-sensitive INa of voltage-clamped neurons acutely dissociated from adult rat DRG. We examined only small and large neurons whose respective INa were >50% and >80% TTX-sensitive. KEY RESULTS In both small and large neurons, the ability of the toxins to block TTX-sensitive INa was μ-TIIIA < μ-PIIIA < μ-SmIIIA, with the latter blocking ≳90%. Comparison of the toxin-susceptibility profiles of the neuronal INa with recently acquired profiles of rat NaV 1-isoforms, co-expressed with various NaV β-subunits in X. laevis oocytes, were consistent: NaV 1.1, 1.6 and 1.7 could account for all of the TTX-sensitive INa , with NaV 1.1 < NaV 1.6 < NaV 1.7 for small neurons and NaV 1.7 < NaV 1.1 < NaV 1.6 for large neurons. CONCLUSIONS AND IMPLICATIONS Combinations of μ-conotoxins can be used to determine the probable NaV 1-isoforms underlying the INa in DRG neurons. Preliminary experiments with sympathetic neurons suggest that this approach is extendable to other neurons.
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Affiliation(s)
- Min-Min Zhang
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
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18
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Mechanism of μ-conotoxin PIIIA binding to the voltage-gated Na+ channel NaV1.4. PLoS One 2014; 9:e93267. [PMID: 24676211 PMCID: PMC3968119 DOI: 10.1371/journal.pone.0093267] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/03/2014] [Indexed: 12/19/2022] Open
Abstract
Several subtypes of voltage-gated Na+ (NaV) channels are important targets for pain management. μ-Conotoxins isolated from venoms of cone snails are potent and specific blockers of different NaV channel isoforms. The inhibitory effect of μ-conotoxins on NaV channels has been examined extensively, but the mechanism of toxin specificity has not been understood in detail. Here the known structure of μ-conotoxin PIIIA and a model of the skeletal muscle channel NaV1.4 are used to elucidate elements that contribute to the structural basis of μ-conotoxin binding and specificity. The model of NaV1.4 is constructed based on the crystal structure of the bacterial NaV channel, NaVAb. Six different binding modes, in which the side chain of each of the basic residues carried by the toxin protrudes into the selectivity filter of NaV1.4, are examined in atomic detail using molecular dynamics simulations with explicit solvent. The dissociation constants (Kd) computed for two selected binding modes in which Lys9 or Arg14 from the toxin protrudes into the filter of the channel are within 2 fold; both values in close proximity to those determined from dose response data for the block of NaV currents. To explore the mechanism of PIIIA specificity, a double mutant of NaV1.4 mimicking NaV channels resistant to μ-conotoxins and tetrodotoxin is constructed and the binding of PIIIA to this mutant channel examined. The double mutation causes the affinity of PIIIA to reduce by two orders of magnitude.
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19
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Akondi KB, Lewis RJ, Alewood PF. Re-engineering the μ-conotoxin SIIIA scaffold. Biopolymers 2014; 101:347-54. [DOI: 10.1002/bip.22368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/21/2013] [Accepted: 07/26/2013] [Indexed: 12/19/2022]
Affiliation(s)
- K. B. Akondi
- Institute for Molecular Bioscience (IMB); The University of Queensland; Brisbane 4072 Queensland Australia
| | - R. J. Lewis
- Institute for Molecular Bioscience (IMB); The University of Queensland; Brisbane 4072 Queensland Australia
| | - P. F. Alewood
- Institute for Molecular Bioscience (IMB); The University of Queensland; Brisbane 4072 Queensland Australia
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20
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Abstract
Voltage-gated sodium (Nav) channels are essential contributors to neuronal excitability, making them the most commonly targeted ion channel family by toxins found in animal venoms. These molecules can be used to probe the functional aspects of Nav channels on a molecular level and to explore their physiological role in normal and diseased tissues. This chapter summarizes our existing knowledge of the mechanisms by which animal toxins influence Nav channels as well as their potential application in designing therapeutic drugs.
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21
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Markgraf R, Leipold E, Schirmeyer J, Paolini-Bertrand M, Hartley O, Heinemann SH. Mechanism and molecular basis for the sodium channel subtype specificity of µ-conopeptide CnIIIC. Br J Pharmacol 2013; 167:576-86. [PMID: 22537004 DOI: 10.1111/j.1476-5381.2012.02004.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Voltage-gated sodium channels (Na(V) channels) are key players in the generation and propagation of action potentials, and selective blockade of these channels is a promising strategy for clinically useful suppression of electrical activity. The conotoxin µ-CnIIIC from the cone snail Conus consors exhibits myorelaxing activity in rodents through specific blockade of skeletal muscle (Na(V) 1.4) Na(V) channels. EXPERIMENTAL APPROACH We investigated the activity of µ-CnIIIC on human Na(V) channels and characterized its inhibitory mechanism, as well as the molecular basis, for its channel specificity. KEY RESULTS Similar to rat paralogs, human Na(V) 1.4 and Na(V) 1.2 were potently blocked by µ-CnIIIC, the sensitivity of Na(V) 1.7 was intermediate, and Na(V) 1.5 and Na(V) 1.8 were insensitive. Half-channel chimeras revealed that determinants for the insensitivity of Na(V) 1.8 must reside in both the first and second halves of the channel, while those for Na(V) 1.5 are restricted to domains I and II. Furthermore, domain I pore loop affected the total block and therefore harbours the major determinants for the subtype specificity. Domain II pore loop only affected the kinetics of toxin binding and dissociation. Blockade by µ-CnIIIC of Na(V) 1.4 was virtually irreversible but left a residual current of about 5%, reflecting a 'leaky' block; therefore, Na(+) ions still passed through µ-CnIIIC-occupied Na(V) 1.4 to some extent. TTX was excluded from this binding site but was trapped inside the pore by µ-CnIIIC. CONCLUSION AND IMPLICATIONS Of clinical significance, µ-CnIIIC is a potent and persistent blocker of human skeletal muscle Na(V) 1.4 that does not affect activity of cardiac Na(V) 1.5.
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Affiliation(s)
- René Markgraf
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University of Jena & Jena University Hospital, Germany
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22
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Knapp O, Nevin ST, Yasuda T, Lawrence N, Lewis RJ, Adams DJ. Biophysical properties of Na(v) 1.8/Na(v) 1.2 chimeras and inhibition by µO-conotoxin MrVIB. Br J Pharmacol 2012; 166:2148-60. [PMID: 22452751 DOI: 10.1111/j.1476-5381.2012.01955.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Voltage-gated sodium channels are expressed primarily in excitable cells and play a pivotal role in the initiation and propagation of action potentials. Nine subtypes of the pore-forming α-subunit have been identified, each with a distinct tissue distribution, biophysical properties and sensitivity to tetrodotoxin (TTX). Na(v) 1.8, a TTX-resistant (TTX-R) subtype, is selectively expressed in sensory neurons and plays a pathophysiological role in neuropathic pain. In comparison with TTX-sensitive (TTX-S) Na(v) α-subtypes in neurons, Na(v) 1.8 is most strongly inhibited by the µO-conotoxin MrVIB from Conus marmoreus. To determine which domain confers Na(v) 1.8 α-subunit its biophysical properties and MrVIB binding, we constructed various chimeric channels incorporating sequence from Na(v) 1.8 and the TTX-S Na(v) 1.2 using a domain exchange strategy. EXPERIMENTAL APPROACH Wild-type and chimeric Na(v) channels were expressed in Xenopus oocytes, and depolarization-activated Na⁺ currents were recorded using the two-electrode voltage clamp technique. KEY RESULTS MrVIB (1 µM) reduced Na(v) 1.2 current amplitude to 69 ± 12%, whereas Na(v) 1.8 current was reduced to 31 ± 3%, confirming that MrVIB has a binding preference for Na(v) 1.8. A similar reduction in Na⁺ current amplitude was observed when MrVIB was applied to chimeras containing the region extending from S6 segment of domain I through the S5-S6 linker of domain II of Na(v) 1.8. In contrast, MrVIB had only a small effect on Na⁺ current for chimeras containing the corresponding region of Na(v) 1.2. CONCLUSIONS AND IMPLICATIONS Taken together, these results suggest that domain II of Na(v) 1.8 is an important determinant of MrVIB affinity, highlighting a region of the α-subunit that may allow further nociceptor-specific ligand targeting.
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Affiliation(s)
- O Knapp
- Health Innovations Research Institute, RMIT University, Melbourne, Vic, Australia
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Knapp O, McArthur JR, Adams DJ. Conotoxins targeting neuronal voltage-gated sodium channel subtypes: potential analgesics? Toxins (Basel) 2012. [PMID: 23202314 PMCID: PMC3509706 DOI: 10.3390/toxins4111236] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSC) are the primary mediators of electrical signal amplification and propagation in excitable cells. VGSC subtypes are diverse, with different biophysical and pharmacological properties, and varied tissue distribution. Altered VGSC expression and/or increased VGSC activity in sensory neurons is characteristic of inflammatory and neuropathic pain states. Therefore, VGSC modulators could be used in prospective analgesic compounds. VGSCs have specific binding sites for four conotoxin families: μ-, μO-, δ- and ί-conotoxins. Various studies have identified that the binding site of these peptide toxins is restricted to well-defined areas or domains. To date, only the μ- and μO-family exhibit analgesic properties in animal pain models. This review will focus on conotoxins from the μ- and μO-families that act on neuronal VGSCs. Examples of how these conotoxins target various pharmacologically important neuronal ion channels, as well as potential problems with the development of drugs from conotoxins, will be discussed.
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Affiliation(s)
- Oliver Knapp
- Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3083, Australia.
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Nardi A, Damann N, Hertrampf T, Kless A. Advances in targeting voltage-gated sodium channels with small molecules. ChemMedChem 2012; 7:1712-40. [PMID: 22945552 DOI: 10.1002/cmdc.201200298] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/30/2012] [Indexed: 12/19/2022]
Abstract
Blockade of voltage-gated sodium channels (VGSCs) has been used successfully in the clinic to enable control of pathological firing patterns that occur in conditions as diverse as chronic pain, epilepsy, and arrhythmias. Herein we review the state of the art in marketed sodium channel inhibitors, including a brief compendium of their binding sites and of the cellular and molecular biology of sodium channels. Despite the preferential action of this drug class toward over-excited cells, which significantly limits potential undesired side effects on other cells, the need to develop a second generation of sodium channel inhibitors to overcome their critical clinical shortcomings is apparent. Current approaches in drug discovery to deliver novel and truly innovative sodium channel inhibitors is next presented by surveying the most recent medicinal chemistry breakthroughs in the field of small molecules and developments in automated patch-clamp platforms. Various strategies aimed at identifying small molecules that target either particular isoforms of sodium channels involved in specific diseases or anomalous sodium channel currents, irrespective of the isoform by which they have been generated, are critically discussed and revised.
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Affiliation(s)
- Antonio Nardi
- Global Drug Discovery, Department of Medicinal Chemistry, Grünenthal, Zieglerstrasse 6, 52078 Aachen, Germany.
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25
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Stevens M, Peigneur S, Dyubankova N, Lescrinier E, Herdewijn P, Tytgat J. Design of bioactive peptides from naturally occurring μ-conotoxin structures. J Biol Chem 2012; 287:31382-92. [PMID: 22773842 DOI: 10.1074/jbc.m112.375733] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To date, cone snail toxins ("conotoxins") are of great interest in the pursuit of novel subtype-selective modulators of voltage-gated sodium channels (Na(v)s). Na(v)s participate in a wide range of electrophysiological processes. Consequently, their malfunctioning has been associated with numerous diseases. The development of subtype-selective modulators of Na(v)s remains highly important in the treatment of such disorders. In current research, a series of novel, synthetic, and bioactive compounds were designed based on two naturally occurring μ-conotoxins that target Na(v)s. The initial designed peptide contains solely 13 amino acids and was therefore named "Mini peptide." It was derived from the μ-conotoxins KIIIA and BuIIIC. Based on this Mini peptide, 10 analogues were subsequently developed, comprising 12-16 amino acids with two disulfide bridges. Following appropriate folding and mass verification, blocking effects on Na(v)s were investigated. The most promising compound established an IC(50) of 34.1 ± 0.01 nM (R2-Midi on Na(v)1.2). An NMR structure of one of our most promising compounds was determined. Surprisingly, this structure does not reveal an α-helix. We prove that it is possible to design small peptides based on known pharmacophores of μ-conotoxins without losing their potency and selectivity. These data can provide crucial material for further development of conotoxin-based therapeutics.
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Affiliation(s)
- Marijke Stevens
- Laboratory of Toxicology, Katholieke Universiteit (KU) Leuven, Campus Gasthuisberg O and N2, Herestraat 49 Box 922, 3000 Leuven, Belgium
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26
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Lewis RJ, Dutertre S, Vetter I, Christie MJ. Conus Venom Peptide Pharmacology. Pharmacol Rev 2012; 64:259-98. [DOI: 10.1124/pr.111.005322] [Citation(s) in RCA: 323] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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