1
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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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2
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Hadiatullah H, Zhang Y, Samurkas A, Xie Y, Sundarraj R, Zuilhof H, Qiao J, Yuchi Z. Recent progress in the structural study of ion channels as insecticide targets. INSECT SCIENCE 2022; 29:1522-1551. [PMID: 35575601 DOI: 10.1111/1744-7917.13032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 02/07/2022] [Accepted: 02/21/2022] [Indexed: 06/15/2023]
Abstract
Ion channels, many expressed in insect neural and muscular systems, have drawn huge attention as primary targets of insecticides. With the recent technical breakthroughs in structural biology, especially in cryo-electron microscopy (cryo-EM), many new high-resolution structures of ion channel targets, apo or in complex with insecticides, have been solved, shedding light on the molecular mechanism of action of the insecticides and resistance mutations. These structures also provide accurate templates for structure-based insecticide screening and rational design. This review summarizes the recent progress in the structural studies of 5 ion channel families: the ryanodine receptor (RyR), the nicotinic acetylcholine receptor (nAChR), the voltage-gated sodium channel (VGSC), the transient receptor potential (TRP) channel, and the ligand-gated chloride channel (LGCC). We address the selectivity of the channel-targeting insecticides by examining the conservation of key coordinating residues revealed by the structures. The possible resistance mechanisms are proposed based on the locations of the identified resistance mutations on the 3D structures of the target channels and their impacts on the binding of insecticides. Finally, we discuss how to develop "green" insecticides with a novel mode of action based on these high-resolution structures to overcome the resistance.
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Affiliation(s)
- Hadiatullah Hadiatullah
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Yongliang Zhang
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Arthur Samurkas
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Laboratory of Organic Chemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Yunxuan Xie
- Department of Environmental Science, Tianjin University, Tianjin, China
| | - Rajamanikandan Sundarraj
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
| | - Han Zuilhof
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Laboratory of Organic Chemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Jianjun Qiao
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, Collaborative Innovation Center of Chemical Science and Engineering, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China
- Department of Molecular Pharmacology, Tianjin Medical University Cancer Institute & Hospital; National Clinical Research Center for Cancer; Key Laboratory of Cancer Prevention and Therapy, Tianjin; Tianjin's Clinical Research Center for Cancer, Tianjin, China
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3
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Jimenez EC. Peptide antagonists of NMDA receptors: Structure-activity relationships for potential therapeutics. Peptides 2022; 153:170796. [PMID: 35367253 DOI: 10.1016/j.peptides.2022.170796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 03/26/2022] [Accepted: 03/27/2022] [Indexed: 12/19/2022]
Abstract
The N-methyl-D-aspartate (NMDA) receptors are heteromeric cation channels involved in memory, learning, and synaptic plasticity. The dysfunction associated with NMDA receptors results in neurodegenerative conditions. The conantokins comprise a family of Conus venom peptides that induce sleep upon intracranial injection into young mice and are known to be NMDA receptor antagonists. This work comprehensibly documents the conantokins that have been characterized to date, focusing on the biochemistry, solution structures in the presence or absence of divalent cations, functions as selective NMDA receptor antagonists, and structure-activity relationships. Furthermore, the applications of conantokins as potential therapeutics for certain neurological conditions, including neuropathic pain, epilepsy, and ischaemia that are linked to NMDA receptor dysfunction are reviewed.
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Affiliation(s)
- Elsie C Jimenez
- Department of Physical Sciences, College of Science, University of the Philippines Baguio, Baguio City 2600, Philippines.
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4
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Nevin ST, Lawrence N, Nicke A, Lewis RJ, Adams DJ. Functional modulation of the human voltage-gated sodium channel Na V1.8 by auxiliary β subunits. Channels (Austin) 2021; 15:79-93. [PMID: 33315536 PMCID: PMC7781643 DOI: 10.1080/19336950.2020.1860399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 11/30/2020] [Accepted: 11/30/2020] [Indexed: 12/03/2022] Open
Abstract
The voltage-gated sodium channel Nav1.8 mediates the tetrodotoxin-resistant (TTX-R) Na+ current in nociceptive primary sensory neurons, which has an important role in the transmission of painful stimuli. Here, we describe the functional modulation of the human Nav1.8 α-subunit in Xenopus oocytes by auxiliary β subunits. We found that the β3 subunit down-regulated the maximal Na+ current amplitude and decelerated recovery from inactivation of hNav1.8, whereas the β1 and β2 subunits had no such effects. The specific regulation of Nav1.8 by the β3 subunit constitutes a potential novel regulatory mechanism of the TTX-R Na+ current in primary sensory neurons with potential implications in chronic pain states. In particular, neuropathic pain states are characterized by a down-regulation of Nav1.8 accompanied by increased expression of the β3 subunit. Our results suggest that these two phenomena may be correlated, and that increased levels of the β3 subunit may directly contribute to the down-regulation of Nav1.8. To determine which domain of the β3 subunit is responsible for the specific regulation of hNav1.8, we created chimeras of the β1 and β3 subunits and co-expressed them with the hNav1.8 α-subunit in Xenopus oocytes. The intracellular domain of the β3 subunit was shown to be responsible for the down-regulation of maximal Nav1.8 current amplitudes. In contrast, the extracellular domain mediated the effect of the β3 subunit on hNav1.8 recovery kinetics.
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Affiliation(s)
- S. T. Nevin
- School of Biomedical Sciences and the Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - N. Lawrence
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - A. Nicke
- School of Biomedical Sciences and the Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - R. J. Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - D. J. Adams
- School of Biomedical Sciences and the Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, Australia
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5
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Doray A, Lemoine R, Severin M, Chadet S, Lopez-Charcas O, Héraud A, Baron C, Besson P, Monteil A, Pedersen SF, Roger S. The Voltage-Gated Sodium Channel Beta4 Subunit Maintains Epithelial Phenotype in Mammary Cells. Cells 2021; 10:1624. [PMID: 34209614 PMCID: PMC8304757 DOI: 10.3390/cells10071624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/17/2021] [Accepted: 06/25/2021] [Indexed: 11/16/2022] Open
Abstract
The SCN4B gene, coding for the NaVβ4 subunit of voltage-gated sodium channels, was recently found to be expressed in normal epithelial cells and down-regulated in several cancers. However, its function in normal epithelial cells has not been characterized. In this study, we demonstrated that reducing NaVβ4 expression in MCF10A non-cancer mammary epithelial cells generated important morphological changes observed both in two-dimensional cultures and in three-dimensional cysts. Most notably, the loss of NaVβ4 induced a complete loss of epithelial organisation in cysts and increased proteolytic activity towards the extracellular matrix. Loss of epithelial morphology was associated with an increased degradation of β-catenin, reduced E-cadherin expression and induction of mesenchymal markers N-cadherin, vimentin, and α-SMA expression. Overall, our results suggest that Navβ4 may participate in the maintenance of the epithelial phenotype in mammary cells and that its downregulation might be a determining step in early carcinogenesis.
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Affiliation(s)
- Adélaïde Doray
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Roxane Lemoine
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Marc Severin
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen, Denmark; (M.S.); (S.F.P.)
| | - Stéphanie Chadet
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Osbaldo Lopez-Charcas
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Audrey Héraud
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Christophe Baron
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Pierre Besson
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, University of Montpellier, CNRS UMR 5203, INSERM U1191, 34094 Montpellier, France;
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen, Denmark; (M.S.); (S.F.P.)
| | - Sébastien Roger
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
- Institut Universitaire de France (IUF), 75231 Paris, France
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6
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Jimenez EC. Post-translationally modified conopeptides: Biological activities and pharmacological applications. Peptides 2021; 139:170525. [PMID: 33684482 DOI: 10.1016/j.peptides.2021.170525] [Citation(s) in RCA: 3] [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: 12/30/2020] [Revised: 02/20/2021] [Accepted: 02/24/2021] [Indexed: 10/25/2022]
Abstract
Conus venoms comprise a large variety of biologically active peptides (conopeptides or conotoxins) that are employed for prey capture and other biological functions. Throughout the course of evolution of the cone snails, they have developed an envenomation scheme that necessitates a potent mixture of peptides, most of which are highly post-translationally modified, that can cause rapid paralysis of their prey. The great diversity of these peptides defines the ecological interactions and evolutionary strategy of cone snails. Such scheme has led to some pharmacological applications for pain, epilepsy, and myocardial infarction, that could be further explored to ultimately find unique peptide-based therapies. This review focuses on ∼ 60 representative post-translationally modified conopeptides that were isolated from Conus venoms. Various conopeptides reveal post-translational modifications of specific amino acids, such as hydroxylation of proline and lysine, gamma-carboxylation of glutamate, formation of N-terminal pyroglutamate, isomerization of l- to d-amino acid, bromination of tryptophan, O-glycosylation of threonine or serine, sulfation of tyrosine, and cysteinylation of cysteine, other than the more common disulfide crosslinking and C-terminal amidation. Many of the post-translationally modified peptides paved the way for the characterization, by alternative analytical methods, of other pharmacologically important peptides that are classified under 27 conopeptide families denoting pharmacological classes.
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Affiliation(s)
- Elsie C Jimenez
- Department of Physical Sciences, College of Science, University of the Philippines Baguio, Baguio City, 2600, Philippines.
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7
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Yang M, Zhou M. μ-conotoxin TsIIIA, a peptide inhibitor of human voltage-gated sodium channel hNa v1.8. Toxicon 2020; 186:29-34. [PMID: 32758497 DOI: 10.1016/j.toxicon.2020.07.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022]
Abstract
TsIIIA, the first μ-conotoxin from Conus tessulatus, can selectively inhibit rat tetrodotoxin-resistant sodium channels. TsIIIA also shows potent analgesic activity in a mice hotplate analgesic assay, but its effect on human sodium channels remains unknown. In this study, eight human sodium channel subtypes, hNav1.1- hNav1.8, were expressed in HEK293 or ND7/23 cells and tested on the chemically synthesized TsIIIA. Patch clamp experiments showed that 10 μM TsIIIA had no effects on the tetrodotoxin-sensitive hNav1.1, hNav1.2, hNav1.3, hNav1.4, hNav1.6 and hNav1.7, as well as tetrodotoxin-resistant hNav1.5. For tetrodotoxin-resistant hNav1.8, concentrations of 1, 5 and 10 μM TsIIIA reduced the hNav1.8 currents to 59.26%, 36.21% and 24.93% respectively. Further detailed dose-effect experiments showed that TsIIIA inhibited hNav1.8 currents with an IC50 value of 2.11 μM. In addition, 2 μM TsIIIA did not induce a shift in the current-voltage relationship of hNav1.8. Taken together, the hNav1.8 peptide inhibitor TsIIIA provides a pharmacological probe for sodium channels and a potential therapeutic agent for pain.
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Affiliation(s)
- Manyi Yang
- Department of Hepatobiliary and Pancreatic Surgery, NHC Key Laboratory of Nanobiological Technology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Maojun Zhou
- Department of Oncology, State Local Joint Engineering Laboratory for Anticancer Drugs, NHC Key Laboratory of Cancer Proteomics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
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8
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Fu Y, Li C, Dong S, Wu Y, Zhangsun D, Luo S. Discovery Methodology of Novel Conotoxins from Conus Species. Mar Drugs 2018; 16:md16110417. [PMID: 30380764 PMCID: PMC6266589 DOI: 10.3390/md16110417] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 10/21/2018] [Accepted: 10/25/2018] [Indexed: 12/17/2022] Open
Abstract
Cone snail venoms provide an ideal resource for neuropharmacological tools and drug candidates discovery, which have become a research hotspot in neuroscience and new drug development. More than 1,000,000 natural peptides are produced by cone snails, but less than 0.1% of the estimated conotoxins has been characterized to date. Hence, the discovery of novel conotoxins from the huge conotoxin resources with high-throughput and sensitive methods becomes a crucial key for the conotoxin-based drug development. In this review, we introduce the discovery methodology of new conotoxins from various Conus species. It focuses on obtaining full N- to C-terminal sequences, regardless of disulfide bond connectivity through crude venom purification, conotoxin precusor gene cloning, venom duct transcriptomics, venom proteomics and multi-omic methods. The protocols, advantages, disadvantages, and developments of different approaches during the last decade are summarized and the promising prospects are discussed as well.
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Affiliation(s)
- Ying Fu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University, Haikou 570228, China.
| | - Cheng Li
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University, Haikou 570228, China.
| | - Shuai Dong
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University, Haikou 570228, China.
| | - Yong Wu
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University, Haikou 570228, China.
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources, Ministry of Education, Hainan University, Haikou 570228, China.
| | - Sulan Luo
- Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
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9
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Cardoso FC, Lewis RJ. Sodium channels and pain: from toxins to therapies. Br J Pharmacol 2018; 175:2138-2157. [PMID: 28749537 PMCID: PMC5980290 DOI: 10.1111/bph.13962] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/11/2017] [Accepted: 07/17/2017] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium channels (NaV channels) are essential for the initiation and propagation of action potentials that critically influence our ability to respond to a diverse range of stimuli. Physiological and pharmacological studies have linked abnormal function of NaV channels to many human disorders, including chronic neuropathic pain. These findings, along with the description of the functional properties and expression pattern of NaV channel subtypes, are helping to uncover subtype specific roles in acute and chronic pain and revealing potential opportunities to target these with selective inhibitors. High-throughput screens and automated electrophysiology platforms have identified natural toxins as a promising group of molecules for the development of target-specific analgesics. In this review, the role of toxins in defining the contribution of NaV channels in acute and chronic pain states and their potential to be used as analgesic therapies are discussed. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
- Fernanda C Cardoso
- Department of Chemistry and Structural Biology, Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLDAustralia
| | - Richard J Lewis
- Department of Chemistry and Structural Biology, Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLDAustralia
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10
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Zhou X, Zhang Y, Tang D, Liang S, Chen P, Tang C, Liu Z. A Chimeric NaV1.8 Channel Expression System Based on HEK293T Cell Line. Front Pharmacol 2018; 9:337. [PMID: 29686617 PMCID: PMC5900924 DOI: 10.3389/fphar.2018.00337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/22/2018] [Indexed: 11/13/2022] Open
Abstract
Among the nine voltage-gated sodium channel (NaV) subtypes, NaV1.8 is an attractive therapeutic target for pain. The heterologous expression of recombinant NaV1.8 currents is of particular importance for its electrophysiological and pharmacological studies. However, NaV1.8 expresses no or low-level functional currents when transiently transfected into non-neuronal cell lines. The present study aims to explore the molecular determinants limiting its functional expression and accordingly establish a functional NaV1.8 expression system. We conducted screening analysis of the NaV1.8 intracellular loops by constructing NaV chimeric channels and confirmed that the NaV1.8 C-terminus was the only limiting factor. Replacing this sequence with that of NaV1.4, NaV1.5, or NaV1.7 constructed functional channels (NaV1.8/1.4L5, NaV1.8/1.5L5, and NaV1.8/1.7L5, respectively), which expressed high-level NaV1.8-like currents in HEK293T cells. The chimeric channel NaV1.8/1.7L5 displayed much faster inactivation of its macroscopic currents than NaV1.8/1.4L5 and NaV1.8/1.5L5, and it was the most similar to wild-type NaV1.8 expressed in ND7/23 cells. Its currents were very stable during repetitive depolarizations, while its repriming kinetic was different from wild-type NaV1.8. Most importantly, NaV1.8/1.7L5 pharmacologically resembled wild-type NaV1.8 as revealed by testing their susceptibility to two NaV1.8 selective antagonists, APETx-2 and MrVIB. NaV chimeras study showed that at least the domain 2 and domain 4 of NaV1.8 were involved in binding with APETx-2. Our study provided new insights into the function of NaV1.8 intracellular loops, as well as a reliable and convenient expression system which could be useful in NaV1.8 studies.
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Affiliation(s)
| | | | | | | | | | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
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11
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Hull JM, Isom LL. Voltage-gated sodium channel β subunits: The power outside the pore in brain development and disease. Neuropharmacology 2017; 132:43-57. [PMID: 28927993 DOI: 10.1016/j.neuropharm.2017.09.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/19/2017] [Accepted: 09/11/2017] [Indexed: 12/19/2022]
Abstract
Voltage gated sodium channels (VGSCs) were first identified in terms of their role in the upstroke of the action potential. The underlying proteins were later identified as saxitoxin and scorpion toxin receptors consisting of α and β subunits. We now know that VGSCs are heterotrimeric complexes consisting of a single pore forming α subunit joined by two β subunits; a noncovalently linked β1 or β3 and a covalently linked β2 or β4 subunit. VGSC α subunits contain all the machinery necessary for channel cell surface expression, ion conduction, voltage sensing, gating, and inactivation, in one central, polytopic, transmembrane protein. VGSC β subunits are more than simple accessories to α subunits. In the more than two decades since the original cloning of β1, our knowledge of their roles in physiology and pathophysiology has expanded immensely. VGSC β subunits are multifunctional. They confer unique gating mechanisms, regulate cellular excitability, affect brain development, confer distinct channel pharmacology, and have functions that are independent of the α subunits. The vast array of functions of these proteins stems from their special station in the channelome: being the only known constituents that are cell adhesion and intra/extracellular signaling molecules in addition to being part of channel complexes. This functional trifecta and how it goes awry demonstrates the power outside the pore in ion channel signaling complexes, broadening the term channelopathy beyond defects in ion conduction. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Jacob M Hull
- Neuroscience Program and Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lori L Isom
- Neuroscience Program and Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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12
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Rajamani R, Wu S, Rodrigo I, Gao M, Low S, Megson L, Wensel D, Pieschl RL, Post-Munson DJ, Watson J, Langley DR, Ahlijanian MK, Bristow LJ, Herrington J. A Functional NaV1.7-NaVAb Chimera with a Reconstituted High-Affinity ProTx-II Binding Site. Mol Pharmacol 2017. [DOI: 10.1124/mol.117.108712] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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13
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Deuis JR, Mueller A, Israel MR, Vetter I. The pharmacology of voltage-gated sodium channel activators. Neuropharmacology 2017; 127:87-108. [PMID: 28416444 DOI: 10.1016/j.neuropharm.2017.04.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/28/2017] [Accepted: 04/10/2017] [Indexed: 12/19/2022]
Abstract
Toxins and venom components that target voltage-gated sodium (NaV) channels have evolved numerous times due to the importance of this class of ion channels in the normal physiological function of peripheral and central neurons as well as cardiac and skeletal muscle. NaV channel activators in particular have been isolated from the venom of spiders, wasps, snakes, scorpions, cone snails and sea anemone and are also produced by plants, bacteria and algae. These compounds have provided key insight into the molecular structure, function and pathophysiological roles of NaV channels and are important tools due to their at times exquisite subtype-selectivity. We review the pharmacology of NaV channel activators with particular emphasis on mammalian isoforms and discuss putative applications for these compounds. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Jennifer R Deuis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Alexander Mueller
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Mathilde R Israel
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Irina Vetter
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia.
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14
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Israel MR, Tay B, Deuis JR, Vetter I. Sodium Channels and Venom Peptide Pharmacology. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 79:67-116. [PMID: 28528674 DOI: 10.1016/bs.apha.2017.01.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Venomous animals including cone snails, spiders, scorpions, anemones, and snakes have evolved a myriad of components in their venoms that target the opening and/or closing of voltage-gated sodium channels to cause devastating effects on the neuromuscular systems of predators and prey. These venom peptides, through design and serendipity, have not only contributed significantly to our understanding of sodium channel pharmacology and structure, but they also represent some of the most phyla- and isoform-selective molecules that are useful as valuable tool compounds and drug leads. Here, we review our understanding of the basic function of mammalian voltage-gated sodium channel isoforms as well as the pharmacology of venom peptides that act at these key transmembrane proteins.
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Affiliation(s)
- Mathilde R Israel
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Bryan Tay
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Jennifer R Deuis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
| | - Irina Vetter
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia; School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia.
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15
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Molinarolo S, Granata D, Carnevale V, Ahern CA. Mining Protein Evolution for Insights into Mechanisms of Voltage-Dependent Sodium Channel Auxiliary Subunits. Handb Exp Pharmacol 2017; 246:33-49. [PMID: 29464397 DOI: 10.1007/164_2017_75] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Voltage-gated sodium channel (VGSC) beta (β) subunits have been called the "overachieving" auxiliary ion channel subunit. Indeed, these subunits regulate the trafficking of the sodium channel complex at the plasma membrane and simultaneously tune the voltage-dependent properties of the pore-forming alpha-subunit. It is now known that VGSC β-subunits are capable of similar modulation of multiple isoforms of related voltage-gated potassium channels, suggesting that their abilities extend into the broader voltage-gated channels. The gene family for these single transmembrane immunoglobulin beta-fold proteins extends well beyond the traditional VGSC β1-β4 subunit designation, with deep roots into the cell adhesion protein family and myelin-related proteins - where inherited mutations result in a myriad of electrical signaling disorders. Yet, very little is known about how VGSC β-subunits support protein trafficking pathways, the basis for their modulation of voltage-dependent gating, and, ultimately, their role in shaping neuronal excitability. An evolutionary approach can be useful in yielding new clues to such functions as it provides an unbiased assessment of protein residues, folds, and functions. An approach is described here which indicates the greater emergence of the modern β-subunits roughly 400 million years ago in the early neurons of Bilateria and bony fish, and the unexpected presence of distant homologues in bacteriophages. Recent structural breakthroughs containing α and β eukaryotic sodium channels containing subunits suggest a novel role for a highly conserved polar contact that occurs within the transmembrane segments. Overall, a mixture of approaches will ultimately advance our understanding of the mechanism for β-subunit interactions with voltage-sensor containing ion channels and membrane proteins.
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Affiliation(s)
- Steven Molinarolo
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Daniele Granata
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA, USA
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA, USA.
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
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16
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Bon E, Driffort V, Gradek F, Martinez-Caceres C, Anchelin M, Pelegrin P, Cayuela ML, Marionneau-Lambot S, Oullier T, Guibon R, Fromont G, Gutierrez-Pajares JL, Domingo I, Piver E, Moreau A, Burlaud-Gaillard J, Frank PG, Chevalier S, Besson P, Roger S. SCN4B acts as a metastasis-suppressor gene preventing hyperactivation of cell migration in breast cancer. Nat Commun 2016; 7:13648. [PMID: 27917859 PMCID: PMC5150224 DOI: 10.1038/ncomms13648] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 10/20/2016] [Indexed: 12/19/2022] Open
Abstract
The development of metastases largely relies on the capacity of cancer cells to invade extracellular matrices (ECM) using two invasion modes termed ‘mesenchymal' and ‘amoeboid', with possible transitions between these modes. Here we show that the SCN4B gene, encoding for the β4 protein, initially characterized as an auxiliary subunit of voltage-gated sodium channels (NaV) in excitable tissues, is expressed in normal epithelial cells and that reduced β4 protein levels in breast cancer biopsies correlate with high-grade primary and metastatic tumours. In cancer cells, reducing β4 expression increases RhoA activity, potentiates cell migration and invasiveness, primary tumour growth and metastatic spreading, by promoting the acquisition of an amoeboid–mesenchymal hybrid phenotype. This hyperactivated migration is independent of NaV and is prevented by overexpression of the intracellular C-terminus of β4. Conversely, SCN4B overexpression reduces cancer cell invasiveness and tumour progression, indicating that SCN4B/β4 represents a metastasis-suppressor gene. The capacity of cancer cells to migrate is intimately linked to their ability to induce metastasis. Here the authors show that the sodium channel β4 subunit regulates breast cancer cell migration via inhibition of RhoA activation, independently from its function as an auxiliary protein of the sodium channel.
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Affiliation(s)
- Emeline Bon
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Virginie Driffort
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Frédéric Gradek
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Carlos Martinez-Caceres
- Inflammation and Experimental Surgery Unit, CIBERehd, Murcia's BioHealth Research Institute IMIB-Arrixaca, Clinical University Hospital Virgen de la Arrixaca, E-30120 Murcia, Spain
| | - Monique Anchelin
- Telomerase, Cancer and Aging Group, Hospital Virgen de la Arrixaca, E-30120 Murcia, Spain
| | - Pablo Pelegrin
- Inflammation and Experimental Surgery Unit, CIBERehd, Murcia's BioHealth Research Institute IMIB-Arrixaca, Clinical University Hospital Virgen de la Arrixaca, E-30120 Murcia, Spain
| | - Maria-Luisa Cayuela
- Telomerase, Cancer and Aging Group, Hospital Virgen de la Arrixaca, E-30120 Murcia, Spain
| | | | - Thibauld Oullier
- Cancéropôle du Grand Ouest, Plateforme In Vivo, 44000 Nantes, France
| | - Roseline Guibon
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France.,CHRU de Tours, 2 Boulevard Tonnellé, 37000 Tours, France
| | - Gaëlle Fromont
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France.,CHRU de Tours, 2 Boulevard Tonnellé, 37000 Tours, France
| | - Jorge L Gutierrez-Pajares
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Isabelle Domingo
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Eric Piver
- CHRU de Tours, 2 Boulevard Tonnellé, 37000 Tours, France.,Inserm, U966, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Alain Moreau
- Inserm, U966, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Julien Burlaud-Gaillard
- Laboratoire de Biologie Cellulaire-Microscopie Electronique, Faculté de Médecine, Université François-Rabelais de Tours, 2 Boulevard Tonnellé, 37000 Tours, France
| | - Philippe G Frank
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France
| | - Stéphan Chevalier
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France.,UFR Sciences Pharmaceutiques, Université François-Rabelais de Tours, 31 Avenue Monge, 37200 Tours, France
| | - Pierre Besson
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France.,UFR Sciences Pharmaceutiques, Université François-Rabelais de Tours, 31 Avenue Monge, 37200 Tours, France
| | - Sébastien Roger
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours, 10 Boulevard Tonnellé, 37032 Tours, France.,UFR Sciences et Techniques, Département de Physiologie Animale, Université François-Rabelais de Tours, Parc de Grandmont, 37200 Tours, France.,Institut Universitaire de France, 1, Rue Descartes, 75231 Paris Cedex 05, France
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17
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Green BR, Olivera BM. Venom Peptides From Cone Snails: Pharmacological Probes for Voltage-Gated Sodium Channels. CURRENT TOPICS IN MEMBRANES 2016; 78:65-86. [PMID: 27586281 DOI: 10.1016/bs.ctm.2016.07.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The venoms of cone snails provide a rich source of neuroactive peptides (conotoxins). Several venom peptide families have been identified that are either agonists (ι- and δ-conotoxins) or antagonists (μ- and μO-conotoxins) of voltage-gated sodium channels (VGSCs). Members of these conotoxin classes have been integral in identifying and characterizing specific neurotoxin binding sites on the channel. Furthermore, given the specificity of some of these peptides for one sodium channel subtype over another, conotoxins have also proven useful in exploring differences between VGSC subtypes. This chapter summarizes the current knowledge of the structure and function based on the results of conotoxin interactions with VGSCs and correlates the peptides with the phylogeny of the Conus species from which they were derived.
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Affiliation(s)
- B R Green
- University of Utah, Salt Lake City, UT, United States; Monash University, Parkville, VIC, Australia
| | - B M Olivera
- University of Utah, Salt Lake City, UT, United States
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18
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Deuis JR, Dekan Z, Inserra MC, Lee TH, Aguilar MI, Craik DJ, Lewis RJ, Alewood PF, Mobli M, Schroeder CI, Henriques ST, Vetter I. Development of a μO-Conotoxin Analogue with Improved Lipid Membrane Interactions and Potency for the Analgesic Sodium Channel NaV1.8. J Biol Chem 2016; 291:11829-42. [PMID: 27026701 DOI: 10.1074/jbc.m116.721662] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Indexed: 12/19/2022] Open
Abstract
The μO-conotoxins MrVIA, MrVIB, and MfVIA inhibit the voltage-gated sodium channel NaV1.8, a well described target for the treatment of pain; however, little is known about the residues or structural elements that define this activity. In this study, we determined the three-dimensional structure of MfVIA, examined its membrane binding properties, performed alanine-scanning mutagenesis, and identified residues important for its activity at human NaV1.8. A second round of mutations resulted in (E5K,E8K)MfVIA, a double mutant with greater positive surface charge and greater affinity for lipid membranes compared with MfVIA. This analogue had increased potency at NaV1.8 and was analgesic in the mouse formalin assay.
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Affiliation(s)
- Jennifer R Deuis
- From the Institute for Molecular Bioscience and School of Pharmacy, The University of Queensland, Woolloongabba, Queensland 4102, Australia, and
| | | | - Marco C Inserra
- From the Institute for Molecular Bioscience and School of Pharmacy, The University of Queensland, Woolloongabba, Queensland 4102, Australia, and
| | - Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | | | | | | | - Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | | | | | - Irina Vetter
- From the Institute for Molecular Bioscience and School of Pharmacy, The University of Queensland, Woolloongabba, Queensland 4102, Australia, and
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19
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Distinctive property and pharmacology of voltage-gated sodium current in rat atrial vs ventricular myocytes. Heart Rhythm 2016; 13:762-70. [DOI: 10.1016/j.hrthm.2015.11.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 02/01/2023]
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20
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Das S, Gilchrist J, Bosmans F, Van Petegem F. Binary architecture of the Nav1.2-β2 signaling complex. eLife 2016; 5. [PMID: 26894959 PMCID: PMC4769172 DOI: 10.7554/elife.10960] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 01/07/2016] [Indexed: 12/15/2022] Open
Abstract
To investigate the mechanisms by which β-subunits influence Nav channel function, we solved the crystal structure of the β2 extracellular domain at 1.35Å. We combined these data with known bacterial Nav channel structural insights and novel functional studies to determine the interactions of specific residues in β2 with Nav1.2. We identified a flexible loop formed by (72)Cys and (75)Cys, a unique feature among the four β-subunit isoforms. Moreover, we found that (55)Cys helps to determine the influence of β2 on Nav1.2 toxin susceptibility. Further mutagenesis combined with the use of spider toxins reveals that (55)Cys forms a disulfide bond with (910)Cys in the Nav1.2 domain II pore loop, thereby suggesting a 1:1 stoichiometry. Our results also provide clues as to which disulfide bonds are formed between adjacent Nav1.2 (912/918)Cys residues. The concepts emerging from this work will help to form a model reflecting the β-subunit location in a Nav channel complex.
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Affiliation(s)
- Samir Das
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - John Gilchrist
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Frank Bosmans
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States.,Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
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21
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Munasinghe NR, Christie MJ. Conotoxins That Could Provide Analgesia through Voltage Gated Sodium Channel Inhibition. Toxins (Basel) 2015; 7:5386-407. [PMID: 26690478 PMCID: PMC4690140 DOI: 10.3390/toxins7124890] [Citation(s) in RCA: 11] [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: 08/14/2015] [Revised: 10/23/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022] Open
Abstract
Chronic pain creates a large socio-economic burden around the world. It is physically and mentally debilitating, and many sufferers are unresponsive to current therapeutics. Many drugs that provide pain relief have adverse side effects and addiction liabilities. Therefore, a great need has risen for alternative treatment strategies. One rich source of potential analgesic compounds that has emerged over the past few decades are conotoxins. These toxins are extremely diverse and display selective activity at ion channels. Voltage gated sodium (NaV) channels are one such group of ion channels that play a significant role in multiple pain pathways. This review will explore the literature around conotoxins that bind NaV channels and determine their analgesic potential.
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Affiliation(s)
- Nehan R Munasinghe
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
| | - MacDonald J Christie
- Discipline of Pharmacology, The University of Sydney, Sydney, NSW 2006, Australia.
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22
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Namadurai S, Yereddi NR, Cusdin FS, Huang CLH, Chirgadze DY, Jackson AP. A new look at sodium channel β subunits. Open Biol 2015; 5:140192. [PMID: 25567098 PMCID: PMC4313373 DOI: 10.1098/rsob.140192] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are intrinsic plasma membrane proteins that initiate the action potential in electrically excitable cells. They are a major focus of research in neurobiology, structural biology, membrane biology and pharmacology. Mutations in Nav channels are implicated in a wide variety of inherited pathologies, including cardiac conduction diseases, myotonic conditions, epilepsy and chronic pain syndromes. Drugs active against Nav channels are used as local anaesthetics, anti-arrhythmics, analgesics and anti-convulsants. The Nav channels are composed of a pore-forming α subunit and associated β subunits. The β subunits are members of the immunoglobulin (Ig) domain family of cell-adhesion molecules. They modulate multiple aspects of Nav channel behaviour and play critical roles in controlling neuronal excitability. The recently published atomic resolution structures of the human β3 and β4 subunit Ig domains open a new chapter in the study of these molecules. In particular, the discovery that β3 subunits form trimers suggests that Nav channel oligomerization may contribute to the functional properties of some β subunits.
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Affiliation(s)
- Sivakumar Namadurai
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Nikitha R Yereddi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Fiona S Cusdin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | | | - Dimitri Y Chirgadze
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Antony P Jackson
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
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23
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Roger S, Gillet L, Le Guennec JY, Besson P. Voltage-gated sodium channels and cancer: is excitability their primary role? Front Pharmacol 2015; 6:152. [PMID: 26283962 PMCID: PMC4518325 DOI: 10.3389/fphar.2015.00152] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/09/2015] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (NaV) are molecular characteristics of excitable cells. Their activation, triggered by membrane depolarization, generates transient sodium currents that initiate action potentials in neurons and muscle cells. Sodium currents were discovered by Hodgkin and Huxley using the voltage clamp technique and reported in their landmark series of papers in 1952. It was only in the 1980's that sodium channel proteins from excitable membranes were molecularly characterized by Catterall and his collaborators. Non-excitable cells can also express NaV channels in physiological conditions as well as in pathological conditions. These NaV channels can sustain biological roles that are not related to the generation of action potentials. Interestingly, it is likely that the abnormal expression of NaV in pathological tissues can reflect the re-expression of a fetal phenotype. This is especially true in epithelial cancer cells for which these channels have been identified and sodium currents recorded, while it was not the case for cells from the cognate normal tissues. In cancers, the functional activity of NaV appeared to be involved in regulating the proliferative, migrative, and invasive properties of cells. This review is aimed at addressing the non-excitable roles of NaV channels with a specific emphasis in the regulation of cancer cell biology.
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Affiliation(s)
- Sébastien Roger
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours Tours, France ; Département de Physiologie Animale, UFR Sciences and Techniques, Université François-Rabelais de Tours Tours, France
| | - Ludovic Gillet
- Department of Clinical Research, University of Bern Bern, Switzerland
| | | | - Pierre Besson
- Inserm UMR1069, Nutrition, Croissance et Cancer, Université François-Rabelais de Tours Tours, France
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24
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Structure and function of μ-conotoxins, peptide-based sodium channel blockers with analgesic activity. Future Med Chem 2015; 6:1677-98. [PMID: 25406007 DOI: 10.4155/fmc.14.107] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
μ-Conotoxins block voltage-gated sodium channels (VGSCs) and compete with tetrodotoxin for binding to the sodium conductance pore. Early efforts identified µ-conotoxins that preferentially blocked the skeletal muscle subtype (NaV1.4). However, the last decade witnessed a significant increase in the number of µ-conotoxins and the range of VGSC subtypes inhibited (NaV1.2, NaV1.3 or NaV1.7). Twenty µ-conotoxin sequences have been identified to date and structure-activity relationship studies of several of these identified key residues responsible for interactions with VGSC subtypes. Efforts to engineer-in subtype specificity are driven by in vivo analgesic and neuromuscular blocking activities. This review summarizes structural and pharmacological studies of µ-conotoxins, which show promise for development of selective blockers of NaV1.2, and perhaps also NaV1.1,1.3 or 1.7.
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25
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Zhang MM, Gajewiak J, Azam L, Bulaj G, Olivera BM, Yoshikami D. Probing the Redox States of Sodium Channel Cysteines at the Binding Site of μO§-Conotoxin GVIIJ. Biochemistry 2015; 54:3911-20. [DOI: 10.1021/acs.biochem.5b00390] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Min-Min Zhang
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Joanna Gajewiak
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Layla Azam
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Grzegorz Bulaj
- Department
of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake
City, Utah 84108, United States
| | - Baldomero M. Olivera
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Doju Yoshikami
- Department
of Biology, University of Utah, Salt Lake City, Utah 84112, United States
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26
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Kwong K, Carr MJ. Voltage-gated sodium channels. Curr Opin Pharmacol 2015; 22:131-9. [PMID: 26043074 DOI: 10.1016/j.coph.2015.04.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/21/2015] [Accepted: 04/29/2015] [Indexed: 12/11/2022]
Abstract
Voltage-gated sodium channels play a key role in the transmission of sensory information about the status of organs in the periphery. Sensory fibers contain a heterogeneous yet specific distribution of voltage-gated sodium channel isoforms. Major efforts by industry and academic groups are underway to develop medicines that interrupt inappropriate signaling for a number of clinical indications by taking advantage of this specific distribution of channel isoforms. This review highlights recent advances in the study of human channelopathies, animal toxins and channel structure that may facilitate the development of selective voltage-gated sodium channel blockers.
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27
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de Lera Ruiz M, Kraus RL. Voltage-Gated Sodium Channels: Structure, Function, Pharmacology, and Clinical Indications. J Med Chem 2015; 58:7093-118. [PMID: 25927480 DOI: 10.1021/jm501981g] [Citation(s) in RCA: 335] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The tremendous therapeutic potential of voltage-gated sodium channels (Na(v)s) has been the subject of many studies in the past and is of intense interest today. Na(v)1.7 channels in particular have received much attention recently because of strong genetic validation of their involvement in nociception. Here we summarize the current status of research in the Na(v) field and present the most relevant recent developments with respect to the molecular structure, general physiology, and pharmacology of distinct Na(v) channel subtypes. We discuss Na(v) channel ligands such as small molecules, toxins isolated from animal venoms, and the recently identified Na(v)1.7-selective antibody. Furthermore, we review eight characterized ligand binding sites on the Na(v) channel α subunit. Finally, we examine possible therapeutic applications of Na(v) ligands and provide an update on current clinical studies.
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Affiliation(s)
- Manuel de Lera Ruiz
- Merck Research Laboratories , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Richard L Kraus
- Merck Research Laboratories , 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
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28
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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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Robinson SD, Safavi-Hemami H, McIntosh LD, Purcell AW, Norton RS, Papenfuss AT. Diversity of conotoxin gene superfamilies in the venomous snail, Conus victoriae. PLoS One 2014; 9:e87648. [PMID: 24505301 PMCID: PMC3914837 DOI: 10.1371/journal.pone.0087648] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 12/28/2013] [Indexed: 12/31/2022] Open
Abstract
Animal venoms represent a vast library of bioactive peptides and proteins with proven potential, not only as research tools but also as drug leads and therapeutics. This is illustrated clearly by marine cone snails (genus Conus), whose venoms consist of mixtures of hundreds of peptides (conotoxins) with a diverse array of molecular targets, including voltage- and ligand-gated ion channels, G-protein coupled receptors and neurotransmitter transporters. Several conotoxins have found applications as research tools, with some being used or developed as therapeutics. The primary objective of this study was the large-scale discovery of conotoxin sequences from the venom gland of an Australian cone snail species, Conus victoriae. Using cDNA library normalization, high-throughput 454 sequencing, de novo transcriptome assembly and annotation with BLASTX and profile hidden Markov models, we discovered over 100 unique conotoxin sequences from 20 gene superfamilies, the highest diversity of conotoxins so far reported in a single study. Many of the sequences identified are new members of known conotoxin superfamilies, some help to redefine these superfamilies and others represent altogether new classes of conotoxins. In addition, we have demonstrated an efficient combination of methods to mine an animal venom gland and generate a library of sequences encoding bioactive peptides.
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Affiliation(s)
- Samuel D. Robinson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- * E-mail: (SDR); (HSH)
| | - Helena Safavi-Hemami
- Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, VIC, Australia
- * E-mail: (SDR); (HSH)
| | - Lachlan D. McIntosh
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Anthony W. Purcell
- Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, VIC, Australia
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Anthony T. Papenfuss
- Bioinformatics Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
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A disulfide tether stabilizes the block of sodium channels by the conotoxin μO§-GVIIJ. Proc Natl Acad Sci U S A 2014; 111:2758-63. [PMID: 24497506 DOI: 10.1073/pnas.1324189111] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A cone snail venom peptide, μO§-conotoxin GVIIJ from Conus geographus, has a unique posttranslational modification, S-cysteinylated cysteine, which makes possible formation of a covalent tether of peptide to its target Na channels at a distinct ligand-binding site. μO§-conotoxin GVIIJ is a 35-aa peptide, with 7 cysteine residues; six of the cysteines form 3 disulfide cross-links, and one (Cys24) is S-cysteinylated. Due to limited availability of native GVIIJ, we primarily used a synthetic analog whose Cys24 was S-glutathionylated (abbreviated GVIIJSSG). The peptide-channel complex is stabilized by a disulfide tether between Cys24 of the peptide and Cys910 of rat (r) NaV1.2. A mutant channel of rNaV1.2 lacking a cysteine near the pore loop of domain II (C910L), was >10(3)-fold less sensitive to GVIIJSSG than was wild-type rNaV1.2. In contrast, although rNaV1.5 was >10(4)-fold less sensitive to GVIIJSSG than NaV1.2, an rNaV1.5 mutant with a cysteine in the homologous location, rNaV1.5[L869C], was >10(3)-fold more sensitive than wild-type rNaV1.5. The susceptibility of rNaV1.2 to GVIIJSSG was significantly altered by treating the channels with thiol-oxidizing or disulfide-reducing agents. Furthermore, coexpression of rNaVβ2 or rNaVβ4, but not that of rNaVβ1 or rNaVβ3, protected rNaV1.1 to -1.7 (excluding NaV1.5) against block by GVIIJSSG. Thus, GVIIJ-related peptides may serve as probes for both the redox state of extracellular cysteines and for assessing which NaVβ- and NaVα-subunits are present in native neurons.
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Crystallographic insights into sodium-channel modulation by the β4 subunit. Proc Natl Acad Sci U S A 2013; 110:E5016-24. [PMID: 24297919 DOI: 10.1073/pnas.1314557110] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are embedded in a multicomponent membrane signaling complex that plays a crucial role in cellular excitability. Although the mechanism remains unclear, β-subunits modify Nav channel function and cause debilitating disorders when mutated. While investigating whether β-subunits also influence ligand interactions, we found that β4 dramatically alters toxin binding to Nav1.2. To explore these observations further, we solved the crystal structure of the extracellular β4 domain and identified (58)Cys as an exposed residue that, when mutated, eliminates the influence of β4 on toxin pharmacology. Moreover, our results suggest the presence of a docking site that is maintained by a cysteine bridge buried within the hydrophobic core of β4. Disrupting this bridge by introducing a β1 mutation implicated in epilepsy repositions the (58)Cys-containing loop and disrupts β4 modulation of Nav1.2. Overall, the principles emerging from this work (i) help explain tissue-dependent variations in Nav channel pharmacology; (ii) enable the mechanistic interpretation of β-subunit-related disorders; and (iii) provide insights in designing molecules capable of correcting aberrant β-subunit behavior.
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Zhang MM, Wilson MJ, Azam L, Gajewiak J, Rivier JE, Bulaj G, Olivera BM, Yoshikami D. Co-expression of Na(V)β subunits alters the kinetics of inhibition of voltage-gated sodium channels by pore-blocking μ-conotoxins. Br J Pharmacol 2013; 168:1597-610. [PMID: 23146020 DOI: 10.1111/bph.12051] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/19/2012] [Accepted: 10/24/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Voltage-gated sodium channels (VGSCs) are assembled from two classes of subunits, a pore-bearing α-subunit (NaV 1) and one or two accessory β-subunits (NaV βs). Neurons in mammals can express one or more of seven isoforms of NaV 1 and one or more of four isoforms of NaV β. The peptide μ-conotoxins, like the guanidinium alkaloids tetrodotoxin (TTX) and saxitoxin (STX), inhibit VGSCs by blocking the pore in NaV 1. Hitherto, the effects of NaV β-subunit co-expression on the activity of these toxins have not been comprehensively assessed. EXPERIMENTAL APPROACH Four μ-conotoxins (μ-TIIIA, μ-PIIIA, μ-SmIIIA and μ-KIIIA), TTX and STX were tested against NaV 1.1, 1.2, 1.6 or 1.7, each co-expressed in Xenopus laevis oocytes with one of NaV β1, β2, β3 or β4 and, for NaV 1.7, binary combinations of thereof. KEY RESULTS Co-expression of NaV β-subunits modifies the block by μ-conotoxins: in general, NaV β1 or β3 co-expression tended to increase kon (in the most extreme instance by ninefold), whereas NaV β2 or β4 co-expression decreased kon (in the most extreme instance by 240-fold). In contrast, the block by TTX and STX was only minimally, if at all, affected by NaV β-subunit co-expression. Tests of NaV β1 : β2 chimeras co-expressed with NaV 1.7 suggest that the extracellular portion of the NaV β subunit is largely responsible for altering μ-conotoxin kinetics. CONCLUSIONS AND IMPLICATIONS These results are the first indication that NaV β subunit co-expression can markedly influence μ-conotoxin binding and, by extension, the outer vestibule of the pore of VGSCs. μ-Conotoxins could, in principle, be used to pharmacologically probe the NaV β subunit composition of endogenously expressed VGSCs.
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Affiliation(s)
- Min-Min Zhang
- Department of Biology, University of Utah, Salt Lake City, UT, USA
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Liu Z, Cai T, Zhu Q, Deng M, Li J, Zhou X, Zhang F, Li D, Li J, Liu Y, Hu W, Liang S. Structure and function of hainantoxin-III, a selective antagonist of neuronal tetrodotoxin-sensitive voltage-gated sodium channels isolated from the Chinese bird spider Ornithoctonus hainana. J Biol Chem 2013; 288:20392-403. [PMID: 23703613 DOI: 10.1074/jbc.m112.426627] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the present study, we investigated the structure and function of hainantoxin-III (HNTX-III), a 33-residue polypeptide from the venom of the spider Ornithoctonus hainana. It is a selective antagonist of neuronal tetrodotoxin-sensitive voltage-gated sodium channels. HNTX-III suppressed Nav1.7 current amplitude without significantly altering the activation, inactivation, and repriming kinetics. Short extreme depolarizations partially activated the toxin-bound channel, indicating voltage-dependent inhibition of HNTX-III. HNTX-III increased the deactivation of the Nav1.7 current after extreme depolarizations. The HNTX-III·Nav1.7 complex was gradually dissociated upon prolonged strong depolarizations in a voltage-dependent manner, and the unbound toxin rebound to Nav1.7 after a long repolarization. Moreover, analysis of chimeric channels showed that the DIIS3-S4 linker was critical for HNTX-III binding to Nav1.7. These data are consistent with HNTX-III interacting with Nav1.7 site 4 and trapping the domain II voltage sensor in the closed state. The solution structure of HNTX-III was determined by two-dimensional NMR and shown to possess an inhibitor cystine knot motif. Structural analysis indicated that certain basic, hydrophobic, and aromatic residues mainly localized in the C terminus may constitute an amphiphilic surface potentially involved in HNTX-III binding to Nav1.7. Taken together, our results show that HNTX-III is distinct from β-scorpion toxins and other β-spider toxins in its mechanism of action and binding specificity and affinity. The present findings contribute to our understanding of the mechanism of toxin-sodium channel interaction and provide a useful tool for the investigation of the structure and function of sodium channel isoforms and for the development of analgesics.
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Affiliation(s)
- Zhonghua Liu
- College of Life Sciences, Hunan Normal University, Changsha, Hunan, 410081, China.
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Eijkelkamp N, Linley JE, Baker MD, Minett MS, Cregg R, Werdehausen R, Rugiero F, Wood JN. Neurological perspectives on voltage-gated sodium channels. Brain 2012; 135:2585-612. [PMID: 22961543 PMCID: PMC3437034 DOI: 10.1093/brain/aws225] [Citation(s) in RCA: 255] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The activity of voltage-gated sodium channels has long been linked to disorders of neuronal excitability such as epilepsy and chronic pain. Recent genetic studies have now expanded the role of sodium channels in health and disease, to include autism, migraine, multiple sclerosis, cancer as well as muscle and immune system disorders. Transgenic mouse models have proved useful in understanding the physiological role of individual sodium channels, and there has been significant progress in the development of subtype selective inhibitors of sodium channels. This review will outline the functions and roles of specific sodium channels in electrical signalling and disease, focusing on neurological aspects. We also discuss recent advances in the development of selective sodium channel inhibitors.
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Affiliation(s)
- Niels Eijkelkamp
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
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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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Vetter I, Dekan Z, Knapp O, Adams DJ, Alewood PF, Lewis RJ. Isolation, characterization and total regioselective synthesis of the novel μO-conotoxin MfVIA from Conus magnificus that targets voltage-gated sodium channels. Biochem Pharmacol 2012; 84:540-8. [PMID: 22609441 DOI: 10.1016/j.bcp.2012.05.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/02/2012] [Accepted: 05/09/2012] [Indexed: 12/19/2022]
Abstract
The μO-conotoxins are notable for their unique selectivity for Na(v)1.8 over other sodium channel isoforms, making them attractive drug leads for the treatment of neuropathic pain. We describe the discovery of a novel μO-conotoxin, MfVIA, from the venom of Conus magnificus using high-throughput screening approaches. MfVIA was found to be a hydrophobic 32-residue peptide (amino acid sequence RDCQEKWEYCIVPILGFVYCCPGLICGPFVCV) with highest sequence homology to μO-conotoxin MrVIB. To overcome the synthetic challenges posed by μO-conotoxins due to their hydrophobic nature and difficult folding, we developed a novel regioselective approach for the synthesis of μO-conotoxins. Performing selective oxidative deprotections of the cysteine side-chain protecting groups of the fully protected peptide allowed manipulations in organic solvents with no chromatography required between steps. Using this approach, we obtained correctly folded MfVIA with increased synthetic yields. Biological activity of MfVIA was assessed using membrane potential-sensitive dyes and electrophysiological recording techniques. MfVIA preferentially inhibits Na(v)1.8 (IC₅₀ 95.9±74.3 nM) and Na(v)1.4 (IC₅₀ 81±16 nM), with significantly lower affinity for other Na(v) subtypes (IC₅₀ 431-6203 nM; Na(v)1.5>1.6∼1.7∼1.3∼1.1∼1.2). This improved approach to μO-conotoxin synthesis will facilitate the optimization of μO-conotoxins as novel analgesic molecules to improve pain management.
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Affiliation(s)
- Irina Vetter
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia
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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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Stevens M, Peigneur S, Tytgat J. Neurotoxins and their binding areas on voltage-gated sodium channels. Front Pharmacol 2011; 2:71. [PMID: 22084632 PMCID: PMC3210964 DOI: 10.3389/fphar.2011.00071] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 10/24/2011] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are large transmembrane proteins that conduct sodium ions across the membrane and by doing so they generate signals of communication between many kinds of tissues. They are responsible for the generation and propagation of action potentials in excitable cells, in close collaboration with other channels like potassium channels. Therefore, genetic defects in sodium channel genes can cause a wide variety of diseases, generally called “channelopathies.” The first insights into the mechanism of action potentials and the involvement of sodium channels originated from Hodgkin and Huxley for which they were awarded the Nobel Prize in 1963. These concepts still form the basis for understanding the function of VGSCs. When VGSCs sense a sufficient change in membrane potential, they are activated and consequently generate a massive influx of sodium ions. Immediately after, channels will start to inactivate and currents decrease. In the inactivated state, channels stay refractory for new stimuli and they must return to the closed state before being susceptible to a new depolarization. On the other hand, studies with neurotoxins like tetrodotoxin (TTX) and saxitoxin (STX) also contributed largely to our today’s understanding of the structure and function of ion channels and of VGSCs specifically. Moreover, neurotoxins acting on ion channels turned out to be valuable lead compounds in the development of new drugs for the enormous range of diseases in which ion channels are involved. A recent example of a synthetic neurotoxin that made it to the market is ziconotide (Prialt®, Elan). The original peptide, ω-MVIIA, is derived from the cone snail Conus magus and now FDA/EMA-approved for the management of severe chronic pain by blocking the N-type voltage-gated calcium channels in pain fibers. This review focuses on the current status of research on neurotoxins acting on VGSC, their contribution to further unravel the structure and function of VGSC and their potential as novel lead compounds in drug development.
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Affiliation(s)
- Marijke Stevens
- Lab of Toxicology, Katholieke Universiteit Leuven Leuven, Belgium
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Rowe AH, Xiao Y, Scales J, Linse KD, Rowe MP, Cummins TR, Zakon HH. Isolation and characterization of CvIV4: a pain inducing α-scorpion toxin. PLoS One 2011; 6:e23520. [PMID: 21887265 PMCID: PMC3160894 DOI: 10.1371/journal.pone.0023520] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 07/19/2011] [Indexed: 12/03/2022] Open
Abstract
Background Among scorpion species, the Buthidae produce the most deadly and painful venoms. However, little is known regarding the venom components that cause pain and their mechanism of action. Using a paw-licking assay (Mus musculus), this study compared the pain-inducing capabilities of venoms from two species of New World scorpion (Centruroides vittatus, C. exilicauda) belonging to the neurotoxin-producing family Buthidae with one species of non-neurotoxin producing scorpion (Vaejovis spinigerus) in the family Vaejovidae. A pain-inducing α-toxin (CvIV4) was isolated from the venom of C. vittatus and tested on five Na+ channel isoforms. Principal Findings C. vittatus and C. exilicauda venoms produced significantly more paw licking in Mus than V. spinigerus venom. CvIV4 produced paw licking in Mus equivalent to the effects of whole venom. CvIV4 slowed the fast inactivation of Nav1.7, a Na+ channel expressed in peripheral pain-pathway neurons (nociceptors), but did not affect the Nav1.8-based sodium currents of these neurons. CvIV4 also slowed the fast inactivation of Nav1.2, Nav1.3 and Nav1.4. The effects of CvIV4 are similar to Old World α-toxins that target Nav1.7 (AahII, BmK MI, LqhIII, OD1), however the primary structure of CvIV4 is not similar to these toxins. Mutant Nav1.7 channels (D1586A and E1589Q, DIV S3–S4 linker) reduced but did not abolish the effects of CvIV4. Conclusions This study: 1) agrees with anecdotal evidence suggesting that buthid venom is significantly more painful than non-neurotoxic venom; 2) demonstrates that New World buthids inflict painful stings via toxins that modulate Na+ channels expressed in nociceptors; 3) reveals that Old and New World buthids employ similar mechanisms to produce pain. Old and New World α-toxins that target Nav1.7 have diverged in sequence, but the activity of these toxins is similar. Pain-inducing toxins may have evolved in a common ancestor. Alternatively, these toxins may be the product of convergent evolution.
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Affiliation(s)
- Ashlee H Rowe
- Section of Neurobiology, University of Texas at Austin, Austin, Texas, United States of America.
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