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Bispat AS, Cardoso FC, Hasan MM, Dongol Y, Wilcox R, Lewis RJ, Duggan PJ, Tuck KL. Inhibition of N-type calcium channels by phenoxyaniline and sulfonamide analogues. RSC Med Chem 2024; 15:916-936. [PMID: 38516585 PMCID: PMC10953480 DOI: 10.1039/d3md00714f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/26/2024] [Indexed: 03/23/2024] Open
Abstract
Building on previous investigations, structural modifications to the neuronal calcium ion channel blocker MONIRO-1 and related compounds were conducted that included replacement of the amide linker with an aniline and isosteric sulfonamide moiety, and the previously used strategy of substitution of the guanidinium group with less hydrophilic amine functionalities. A comprehensive SAR study revealed a number of phenoxyaniline and sulfonamide compounds that were more potent or had similar potency for the CaV2.2 and CaV3.2 channel compared to MONIRO-1 when evaluated in a FLIPR-based intracellular calcium response assay. Cytotoxicity investigations indicated that the sulfonamide analogues were well tolerated by Cos-7 cells at dosages required to inhibit both calcium ion channels. The sulfonamide derivatives were the most promising CaV2.2 inhibitors developed by us to date due, possessing high stability in plasma, low toxicity (estimated therapeutic index > 10), favourable CNS MPO scores (4.0-4.4) and high potency and selectivity, thereby, making this class of compounds suitable candidates for future in vivo studies.
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Affiliation(s)
- Anjie S Bispat
- School of Chemistry, Monash University Victoria 3800 Australia
- CSIRO Manufacturing, Research Way Clayton Victoria 3168 Australia
| | - Fernanda C Cardoso
- Institute for Molecular Bioscience, The University of Queensland St Lucia QLD 4072 Australia
| | - Md Mahadhi Hasan
- Institute for Molecular Bioscience, The University of Queensland St Lucia QLD 4072 Australia
| | - Yashad Dongol
- Institute for Molecular Bioscience, The University of Queensland St Lucia QLD 4072 Australia
| | - Ricki Wilcox
- School of Chemistry, Monash University Victoria 3800 Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland St Lucia QLD 4072 Australia
| | - Peter J Duggan
- CSIRO Manufacturing, Research Way Clayton Victoria 3168 Australia
- College of Science and Engineering, Flinders University Adelaide South Australia 5042 Australia
| | - Kellie L Tuck
- School of Chemistry, Monash University Victoria 3800 Australia
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2
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Sameera, Shah FA, Rashid S. Conformational ensembles of non-peptide ω-conotoxin mimetics and Ca +2 ion binding to human voltage-gated N-type calcium channel Ca v2.2. Comput Struct Biotechnol J 2020; 18:2357-2372. [PMID: 32994894 PMCID: PMC7498737 DOI: 10.1016/j.csbj.2020.08.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 02/07/2023] Open
Abstract
Chronic neuropathic pain is the most complex and challenging clinical problem of a population that sets a major physical and economic burden at the global level. Ca2+-permeable channels functionally orchestrate the processing of pain signals. Among them, N-type voltage-gated calcium channels (VGCC) hold prominent contribution in the pain signal transduction and serve as prime targets for synaptic transmission block and attenuation of neuropathic pain. Here, we present detailed in silico analysis to comprehend the underlying conformational changes upon Ca2+ ion passage through Cav2.2 to differentially correlate subtle transitions induced via binding of a conopeptide-mimetic alkylphenyl ether-based analogue MVIIA. Interestingly, pronounced conformational changes were witnessed at the proximal carboxyl-terminus of Cav2.2 that attained an upright orientation upon Ca+2 ion permeability. Moreover, remarkable changes were observed in the architecture of channel tunnel. These findings illustrate that inhibitor binding to Cav2.2 may induce more narrowing in the pore size as compared to Ca2+ binding through modulating the hydrophilicity pattern at the selectivity region. A significant reduction in the tunnel volume at the selectivity filter and its enhancement at the activation gate of Ca+2-bound Cav2.2 suggests that ion binding modulates the outward splaying of pore-lining S6 helices to open the voltage gate. Overall, current study delineates dynamic conformational ensembles in terms of Ca+2 ion and MVIIA-associated structural implications in the Cav2.2 that may help in better therapeutic intervention to chronic and neuropathic pain management.
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Affiliation(s)
- Sameera
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Fawad Ali Shah
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Sajid Rashid
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
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3
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Cardoso FC, Marliac MA, Geoffroy C, Schmit M, Bispat A, Lewis RJ, Tuck KL, Duggan PJ. The neuronal calcium ion channel activity of constrained analogues of MONIRO-1. Bioorg Med Chem 2020; 28:115655. [DOI: 10.1016/j.bmc.2020.115655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 01/19/2023]
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4
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Wulff H, Christophersen P, Colussi P, Chandy KG, Yarov-Yarovoy V. Antibodies and venom peptides: new modalities for ion channels. Nat Rev Drug Discov 2019; 18:339-357. [PMID: 30728472 PMCID: PMC6499689 DOI: 10.1038/s41573-019-0013-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ion channels play fundamental roles in both excitable and non-excitable tissues and therefore constitute attractive drug targets for myriad neurological, cardiovascular and metabolic diseases as well as for cancer and immunomodulation. However, achieving selectivity for specific ion channel subtypes with small-molecule drugs has been challenging, and there currently is a growing trend to target ion channels with biologics. One approach is to improve the pharmacokinetics of existing or novel venom-derived peptides. In parallel, after initial studies with polyclonal antibodies demonstrated the technical feasibility of inhibiting channel function with antibodies, multiple preclinical programmes are now using the full spectrum of available technologies to generate conventional monoclonal and engineered antibodies or nanobodies against extracellular loops of ion channels. After a summary of the current state of ion channel drug discovery, this Review discusses recent developments using the purinergic receptor channel P2X purinoceptor 7 (P2X7), the voltage-gated potassium channel KV1.3 and the voltage-gated sodium channel NaV1.7 as examples of targeting ion channels with biologics.
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Affiliation(s)
- Heike Wulff
- Department of Pharmacology, University of California Davis, Davis, CA, USA.
| | | | | | - K George Chandy
- Molecular Physiology Laboratory, Infection and Immunity Theme, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Vladimir Yarov-Yarovoy
- Department of Physiology & Membrane Biology, University of California Davis, Davis, CA, USA
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5
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Sairaman A, Cardoso FC, Bispat A, Lewis RJ, Duggan PJ, Tuck KL. Synthesis and evaluation of aminobenzothiazoles as blockers of N- and T-type calcium channels. Bioorg Med Chem 2018; 26:3046-3059. [DOI: 10.1016/j.bmc.2018.03.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/15/2018] [Accepted: 03/18/2018] [Indexed: 10/17/2022]
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6
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McArthur JR, Motin L, Gleeson EC, Spiller S, Lewis RJ, Duggan PJ, Tuck KL, Adams DJ. Inhibition of human N- and T-type calcium channels by an ortho-phenoxyanilide derivative, MONIRO-1. Br J Pharmacol 2017; 175:2284-2295. [PMID: 28608537 DOI: 10.1111/bph.13910] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 03/24/2017] [Accepted: 06/05/2017] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE Voltage-gated calcium channels are involved in nociception in the CNS and in the periphery. N-type (Cav 2.2) and T-type (Cav 3.1, Cav 3.2 and Cav 3.3) voltage-gated calcium channels are particularly important in studying and treating pain and epilepsy. EXPERIMENTAL APPROACH In this study, whole-cell patch clamp electrophysiology was used to assess the potency and mechanism of action of a novel ortho-phenoxylanilide derivative, MONIRO-1, against a panel of voltage-gated calcium channels including Cav 1.2, Cav 1.3, Cav 2.1, Cav 2.2, Cav 2.3, Cav 3.1, Cav 3.2 and Cav 3.3. KEY RESULTS MONIRO-1 was 5- to 20-fold more potent at inhibiting human T-type calcium channels, hCav 3.1, hCav 3.2 and hCav 3.3 (IC50 : 3.3 ± 0.3, 1.7 ± 0.1 and 7.2 ± 0.3 μM, respectively) than N-type calcium channel, hCav 2.2 (IC50 : 34.0 ± 3.6 μM). It interacted with L-type calcium channels Cav 1.2 and Cav 1.3 with significantly lower potency (IC50 > 100 μM) and did not inhibit hCav 2.1 or hCav 2.3 channels at concentrations as high as 100 μM. State- and use-dependent inhibition of hCav 2.2 channels was observed, whereas stronger inhibition occurred at high stimulation frequencies for hCav 3.1 channels suggesting a different mode of action between these two channels. CONCLUSIONS AND IMPLICATIONS Selectivity, potency, reversibility and multi-modal effects distinguish MONIRO-1 from other low MW inhibitors acting on Cav channels involved in pain and/or epilepsy pathways. High-frequency firing increased the affinity for MONIRO-1 for both hCav 2.2 and hCav 3.1 channels. Such Cav channel modulators have potential clinical use in the treatment of epilepsies, neuropathic pain and other nociceptive pathophysiologies. 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)
- Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.,Health Innovations Research Institute, RMIT University, Melbourne, VIC, Australia
| | - Leonid Motin
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.,Health Innovations Research Institute, RMIT University, Melbourne, VIC, Australia
| | - Ellen C Gleeson
- CSIRO Manufacturing, Bag 10, Clayton South, VIC, Australia.,School of Chemistry, Monash University, Clayton, VIC, Australia
| | - Sandro Spiller
- School of Chemistry, Monash University, Clayton, VIC, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Peter J Duggan
- CSIRO Manufacturing, Bag 10, Clayton South, VIC, Australia.,School of Chemical and Physical Sciences, Flinders University, Adelaide, SA, Australia
| | - Kellie L Tuck
- School of Chemistry, Monash University, Clayton, VIC, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.,Health Innovations Research Institute, RMIT University, Melbourne, VIC, Australia
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7
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Harjani JR, Yap BK, Leung EWW, Lucke A, Nicholson SE, Scanlon MJ, Chalmers DK, Thompson PE, Norton RS, Baell JB. Design, Synthesis, and Characterization of Cyclic Peptidomimetics of the Inducible Nitric Oxide Synthase Binding Epitope That Disrupt the Protein–Protein Interaction Involving SPRY Domain-Containing Suppressor of Cytokine Signaling Box Protein (SPSB) 2 and Inducible Nitric Oxide Synthase. J Med Chem 2016; 59:5799-809. [DOI: 10.1021/acs.jmedchem.6b00386] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Jitendra R. Harjani
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Beow Keat Yap
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Eleanor W. W. Leung
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Andrew Lucke
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Sandra E. Nicholson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- The
Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Martin J. Scanlon
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - David K. Chalmers
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Philip E. Thompson
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Raymond S. Norton
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Jonathan B. Baell
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
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8
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Bioactive Mimetics of Conotoxins and other Venom Peptides. Toxins (Basel) 2015; 7:4175-98. [PMID: 26501323 PMCID: PMC4626728 DOI: 10.3390/toxins7104175] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/08/2015] [Indexed: 11/17/2022] Open
Abstract
Ziconotide (Prialt®), a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will include a description of how some of the initially designed mimics have been modified to improve their drug-like properties.
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9
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Gleeson EC, Graham JE, Spiller S, Vetter I, Lewis RJ, Duggan PJ, Tuck KL. Inhibition of N-type calcium channels by fluorophenoxyanilide derivatives. Mar Drugs 2015; 13:2030-45. [PMID: 25871286 PMCID: PMC4413198 DOI: 10.3390/md13042030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 03/18/2015] [Accepted: 03/26/2015] [Indexed: 12/26/2022] Open
Abstract
A set of fluorophenoxyanilides, designed to be simplified analogues of previously reported ω-conotoxin GVIA mimetics, were prepared and tested for N-type calcium channel inhibition in a SH-SY5Y neuroblastoma FLIPR assay. N-type or Cav2.2 channel is a validated target for the treatment of refractory chronic pain. Despite being significantly less complex than the originally designed mimetics, up to a seven-fold improvement in activity was observed.
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MESH Headings
- Analgesics, Non-Narcotic/chemical synthesis
- Analgesics, Non-Narcotic/chemistry
- Analgesics, Non-Narcotic/metabolism
- Analgesics, Non-Narcotic/pharmacology
- Anilides/chemical synthesis
- Anilides/chemistry
- Anilides/metabolism
- Anilides/pharmacology
- Binding, Competitive
- Calcium Channel Blockers/chemical synthesis
- Calcium Channel Blockers/chemistry
- Calcium Channel Blockers/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, N-Type/chemistry
- Calcium Channels, N-Type/metabolism
- Calcium Signaling/drug effects
- Cell Line, Tumor
- Drug Design
- Fluorobenzenes/chemical synthesis
- Fluorobenzenes/chemistry
- Fluorobenzenes/metabolism
- Fluorobenzenes/pharmacology
- High-Throughput Screening Assays
- Humans
- Molecular Structure
- Molecular Targeted Therapy
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/metabolism
- Neuralgia/drug therapy
- Neuralgia/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Neurotoxins/chemistry
- Pain, Intractable/drug therapy
- Pain, Intractable/metabolism
- Structure-Activity Relationship
- omega-Conotoxin GVIA/chemistry
- omega-Conotoxin GVIA/metabolism
- omega-Conotoxin GVIA/pharmacology
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Affiliation(s)
- Ellen C Gleeson
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
- CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
| | - Janease E Graham
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
- CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
| | - Sandro Spiller
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia QLD 4072, Australia.
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia QLD 4072, Australia.
| | - Peter J Duggan
- CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
- School of Chemical and Physical Sciences, Flinders University, Adelaide SA 5042, Australia.
| | - Kellie L Tuck
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
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10
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Guan Z, Hillrichs K, Ünlü C, Rissanen K, Nieger M, Schmidt A. Synthesis of 2-anilinobenzimidates, anthranilamides, and 2,3-dihydroquinazolin-4(1H)-ones from N-heterocyclic carbenes of indazole. Tetrahedron 2015. [DOI: 10.1016/j.tet.2014.11.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Akondi KB, Muttenthaler M, Dutertre S, Kaas Q, Craik DJ, Lewis RJ, Alewood PF. Discovery, synthesis, and structure-activity relationships of conotoxins. Chem Rev 2014; 114:5815-47. [PMID: 24720541 PMCID: PMC7610532 DOI: 10.1021/cr400401e] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | - Sébastien Dutertre
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience, The University of Queensland, Brisbane QLD 4072, Australia
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12
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Lee MS. Recent Progress in the Discovery and Development of N-Type Calcium Channel Modulators for the Treatment of Pain. PROGRESS IN MEDICINAL CHEMISTRY 2014; 53:147-86. [DOI: 10.1016/b978-0-444-63380-4.00004-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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13
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Strategies for the development of conotoxins as new therapeutic leads. Mar Drugs 2013; 11:2293-313. [PMID: 23812174 PMCID: PMC3736424 DOI: 10.3390/md11072293] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 05/27/2013] [Accepted: 06/06/2013] [Indexed: 11/24/2022] Open
Abstract
Peptide toxins typically bind to their target ion channels or receptors with high potency and selectivity, making them attractive leads for therapeutic development. In some cases the native peptide as it is found in the venom from which it originates can be used directly, but in many instances it is desirable to truncate and/or stabilize the peptide to improve its therapeutic properties. A complementary strategy is to display the key residues that make up the pharmacophore of the peptide toxin on a non-peptidic scaffold, thereby creating a peptidomimetic. This review exemplifies these approaches with peptide toxins from marine organisms, with a particular focus on conotoxins.
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14
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Chen R, Chung SH. Complex structures between the N-type calcium channel (CaV2.2) and ω-conotoxin GVIA predicted via molecular dynamics. Biochemistry 2013; 52:3765-72. [PMID: 23651160 DOI: 10.1021/bi4003327] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The N-type voltage-gated Ca(2+) channel CaV2.2 is one of the important targets for pain management. ω-Conotoxins isolated from venoms of cone snails, which specifically inhibit CaV2.2, are promising scaffolds for novel analgesics. The inhibitory action of ω-conotoxins on CaV2.2 has been examined experimentally, but the modes of binding of the toxins to this and other related subfamilies of Ca(2+) channels are not understood in detail. Here molecular dynamics simulations are used to construct models of ω-conotoxin GVIA in complex with a homology model of the pore domain of CaV2.2. Three different binding modes in which the side chain of Lys2, Arg17, or Lys24 from the toxin protrudes into the selectivity filter of CaV2.2 are considered. In all the modes, the toxin forms a salt bridge with an aspartate residue of subunit II just above the EEEE ring of the selectivity filter. Using the umbrella sampling technique and potential of mean force calculations, the half-maximal inhibitory concentration (IC50) values are calculated to be 1.5 and 0.7 nM for the modes in which Lys2 and Arg17 occlude the ion conduction pathway, respectively. Both IC50 values compare favorably with the values of 0.04-1.0 nM determined experimentally. The similar IC50 values calculated for the different binding modes demonstrate that GVIA can inhibit CaV2.2 with alternative binding modes. Such a multiple-binding mode mechanism may be common for ω-conotoxins.
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Affiliation(s)
- Rong Chen
- Research School of Biology, Australian National University , Canberra, ACT 0200, Australia
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15
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Adams DJ, Berecki G. Mechanisms of conotoxin inhibition of N-type (Ca(v)2.2) calcium channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1619-28. [PMID: 23380425 DOI: 10.1016/j.bbamem.2013.01.019] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 01/16/2013] [Accepted: 01/19/2013] [Indexed: 12/27/2022]
Abstract
N-type (Ca(v)2.2) voltage-gated calcium channels (VGCC) transduce electrical activity into other cellular functions, regulate calcium homeostasis and play a major role in processing pain information. Although the distribution and function of these channels vary widely among different classes of neurons, they are predominantly expressed in nerve terminals, where they control neurotransmitter release. To date, genetic and pharmacological studies have identified that high-threshold, N-type VGCCs are important for pain sensation in disease models. This suggests that N-type VGCC inhibitors or modulators could be developed into useful drugs to treat neuropathic pain. This review discusses the role of N-type (Ca(v)2.2) VGCCs in nociception and pain transmission through primary sensory dorsal root ganglion (DRG) neurons (nociceptors). It also outlines the potent and selective inhibition of N-type VGCCs by conotoxins, small disulfide-rich peptides isolated from the venom of marine cone snails. Of these conotoxins, ω-conotoxins are selective N-type VGCC antagonists that preferentially block nociception in inflammatory pain models, and allodynia and/or hyperalgesia in neuropathic pain models. Another conotoxin family, α-conotoxins, were initially proposed as competitive antagonists of muscle and neuronal nicotinic acetylcholine receptors (nAChR). Surprisingly, however, α-conotoxins Vc1.1 and RgIA, also potently inhibit N-type VGCC currents in the sensory DRG neurons of rodents and α9 nAChR knockout mice, via intracellular signaling mediated by G protein-coupled GABAB receptors. Understanding how conotoxins inhibit VGCCs is critical for developing these peptides into analgesics and may result in better pain management. This article is part of a Special Issue entitled: Calcium channels.
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Affiliation(s)
- David J Adams
- Health Innovations Research Institute, RMIT University, Melbourne, Victoria, Australia.
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