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Iseppon F, Luiz AP, Linley JE, Wood JN. Pregabalin Silences Oxaliplatin-Activated Sensory Neurons to Relieve Cold Allodynia. eNeuro 2023; 10:ENEURO.0395-22.2022. [PMID: 36720644 PMCID: PMC9998121 DOI: 10.1523/eneuro.0395-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/05/2022] [Accepted: 12/30/2022] [Indexed: 02/02/2023] Open
Abstract
Oxaliplatin is a platinum-based chemotherapeutic agent that causes cold and mechanical allodynia in up to 90% of patients. Silent Nav1.8-positive nociceptive cold sensors have been shown to be unmasked by oxaliplatin, and this event has been causally linked to the development of cold allodynia. We examined the effects of pregabalin on oxaliplatin-evoked unmasking of cold sensitive neurons using mice expressing GCaMP-3 in all sensory neurons. Intravenous injection of pregabalin significantly ameliorates cold allodynia, while decreasing the number of cold sensitive neurons by altering their excitability and temperature thresholds. The silenced neurons are predominantly medium/large mechano-cold sensitive neurons, corresponding to the "silent" cold sensors activated during neuropathy. Deletion of α2δ1 subunits abolished the effects of pregabalin on both cold allodynia and the silencing of sensory neurons. Thus, these results define a novel, peripheral inhibitory effect of pregabalin on the excitability of "silent" cold-sensing neurons in a model of oxaliplatin-dependent cold allodynia.
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Affiliation(s)
- Federico Iseppon
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
- Discovery UK, Neuroscience, Biopharmaceuticals R&D, AstraZeneca, Cambridge CB21 6GH, United Kingdom
| | - Ana P Luiz
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
| | - John E Linley
- Discovery UK, Neuroscience, Biopharmaceuticals R&D, AstraZeneca, Cambridge CB21 6GH, United Kingdom
| | - John N Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
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2
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Iseppon F, Linley JE, Wood JN. Calcium imaging for analgesic drug discovery. Neurobiology of Pain 2022; 11:100083. [PMID: 35079661 PMCID: PMC8777277 DOI: 10.1016/j.ynpai.2021.100083] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/17/2021] [Accepted: 12/27/2021] [Indexed: 11/24/2022]
Abstract
Calcium imaging is an efficient way to dissect the activity of neurons in vivo. GCaMP indicators can be expressed in specific cell populations for in vivo imaging. Pain research have benefitted greatly from these features in the recent decade. Preclinical research is shifting towards the analysis of pain models and mechanisms. In vivo calcium imaging is the ideal tool for an efficient drug discovery paradigm.
Somatosensation and pain are complex phenomena involving a rangeofspecialised cell types forming different circuits within the peripheral and central nervous systems. In recent decades, advances in the investigation of these networks, as well as their function in sensation, resulted from the constant evolution of electrophysiology and imaging techniques to allow the observation of cellular activity at the population level both in vitro and in vivo. Genetically encoded indicators of neuronal activity, combined with recent advances in DNA engineering and modern microscopy, offer powerful tools to dissect and visualise the activity of specific neuronal subpopulations with high spatial and temporal resolution. In recent years various groups developed in vivo imaging techniques to image calcium transients in the dorsal root ganglia, the spinal cord and the brain of anesthetised and awake, behaving animals to address fundamental questions in both the physiology and pathophysiology of somatosensation and pain. This approach, besides giving unprecedented details on the circuitry of innocuous and painful sensation, can be a very powerful tool for pharmacological research, from the characterisation of new potential drugs to the discovery of new, druggable targets within specific neuronal subpopulations. Here we summarise recent developments in calcium imaging for pain research, discuss technical challenges and advances, and examine the potential positive impact of this technique in early preclinical phases of the analgesic drug discovery process.
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Colley CS, England E, Linley JE, Wilkinson TCI. Screening Strategies for the Discovery of Ion Channel Monoclonal Antibodies. ACTA ACUST UNITED AC 2018; 82:e44. [DOI: 10.1002/cpph.44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Caroline S. Colley
- Antibody Discovery and Protein Engineering, MedImmune; Cambridge United Kingdom
| | - Elizabeth England
- Antibody Discovery and Protein Engineering, MedImmune; Cambridge United Kingdom
| | - John E. Linley
- Neuroscience, IMED Biotech Unit, AstraZeneca; Cambridge United Kingdom
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4
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Kanellopoulos AH, Koenig J, Huang H, Pyrski M, Millet Q, Lolignier S, Morohashi T, Gossage SJ, Jay M, Linley JE, Baskozos G, Kessler BM, Cox JJ, Dolphin AC, Zufall F, Wood JN, Zhao J. Mapping protein interactions of sodium channel Na V1.7 using epitope-tagged gene-targeted mice. EMBO J 2018; 37:427-445. [PMID: 29335280 PMCID: PMC5793798 DOI: 10.15252/embj.201796692] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 11/30/2017] [Accepted: 12/05/2017] [Indexed: 11/24/2022] Open
Abstract
The voltage-gated sodium channel NaV1.7 plays a critical role in pain pathways. We generated an epitope-tagged NaV1.7 mouse that showed normal pain behaviours to identify channel-interacting proteins. Analysis of NaV1.7 complexes affinity-purified under native conditions by mass spectrometry revealed 267 proteins associated with Nav1.7 in vivo The sodium channel β3 (Scn3b), rather than the β1 subunit, complexes with Nav1.7, and we demonstrate an interaction between collapsing-response mediator protein (Crmp2) and Nav1.7, through which the analgesic drug lacosamide regulates Nav1.7 current density. Novel NaV1.7 protein interactors including membrane-trafficking protein synaptotagmin-2 (Syt2), L-type amino acid transporter 1 (Lat1) and transmembrane P24-trafficking protein 10 (Tmed10) together with Scn3b and Crmp2 were validated by co-immunoprecipitation (Co-IP) from sensory neuron extract. Nav1.7, known to regulate opioid receptor efficacy, interacts with the G protein-regulated inducer of neurite outgrowth (Gprin1), an opioid receptor-binding protein, demonstrating a physical and functional link between Nav1.7 and opioid signalling. Further information on physiological interactions provided with this normal epitope-tagged mouse should provide useful insights into the many functions now associated with the NaV1.7 channel.
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Affiliation(s)
| | - Jennifer Koenig
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Honglei Huang
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Martina Pyrski
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Queensta Millet
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Stéphane Lolignier
- Molecular Nociception Group, WIBR, University College London, London, UK
- Université Clermont Auvergne, Inserm U1107 Neuro-Dol, Pharmacologie Fondamentale et Clinique de la Douleur, Clermont-Ferrand, France
| | - Toru Morohashi
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Samuel J Gossage
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Maude Jay
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - John E Linley
- Molecular Nociception Group, WIBR, University College London, London, UK
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | - Benedikt M Kessler
- TDI Mass Spectrometry Laboratory, Target Discovery Institute, University of Oxford, Oxford, UK
| | - James J Cox
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Frank Zufall
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - John N Wood
- Molecular Nociception Group, WIBR, University College London, London, UK
| | - Jing Zhao
- Molecular Nociception Group, WIBR, University College London, London, UK
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Koenig J, Werdehausen R, Linley JE, Habib AM, Vernon J, Lolignier S, Eijkelkamp N, Zhao J, Okorokov AL, Woods CG, Wood JN, Cox JJ. Regulation of Nav1.7: A Conserved SCN9A Natural Antisense Transcript Expressed in Dorsal Root Ganglia. PLoS One 2015; 10:e0128830. [PMID: 26035178 PMCID: PMC4452699 DOI: 10.1371/journal.pone.0128830] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 04/30/2015] [Indexed: 11/19/2022] Open
Abstract
The Nav1.7 voltage-gated sodium channel, encoded by SCN9A, is critical for human pain perception yet the transcriptional and post-transcriptional mechanisms that regulate this gene are still incompletely understood. Here, we describe a novel natural antisense transcript (NAT) for SCN9A that is conserved in humans and mice. The NAT has a similar tissue expression pattern to the sense gene and is alternatively spliced within dorsal root ganglia. The human and mouse NATs exist in cis with the sense gene in a tail-to-tail orientation and both share sequences that are complementary to the terminal exon of SCN9A/Scn9a. Overexpression analyses of the human NAT in human embryonic kidney (HEK293A) and human neuroblastoma (SH-SY5Y) cell lines show that it can function to downregulate Nav1.7 mRNA, protein levels and currents. The NAT may play an important role in regulating human pain thresholds and is a potential candidate gene for individuals with chronic pain disorders that map to the SCN9A locus, such as Inherited Primary Erythromelalgia, Paroxysmal Extreme Pain Disorder and Painful Small Fibre Neuropathy, but who do not contain mutations in the sense gene. Our results strongly suggest the SCN9A NAT as a prime candidate for new therapies based upon augmentation of existing antisense RNAs in the treatment of chronic pain conditions in man.
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Affiliation(s)
- Jennifer Koenig
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
| | - Robert Werdehausen
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
- Department of Anesthesiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Moorenstr. 5, Düsseldorf, Germany
| | - John E. Linley
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
| | - Abdella M. Habib
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
| | - Jeffrey Vernon
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
| | - Stephane Lolignier
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
| | - Niels Eijkelkamp
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
- Laboratory for Translational Immunology, UMC Utrecht, Utrecht, The Netherlands
| | - Jing Zhao
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
| | - Andrei L. Okorokov
- Wolfson Institute for Biomedical Research, University College London, Gower street, London, United Kingdom
| | - C. Geoffrey Woods
- Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge, United Kingdom
| | - John N. Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, College of Medicine, Seoul National University, Seoul, South Korea
| | - James J. Cox
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, Gower Street, London, United Kingdom
- * E-mail:
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Sermadiras I, Revell J, Linley JE, Sandercock A, Ravn P. Recombinant expression and in vitro characterisation of active Huwentoxin-IV. PLoS One 2013; 8:e83202. [PMID: 24324842 PMCID: PMC3855799 DOI: 10.1371/journal.pone.0083202] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/31/2013] [Indexed: 02/06/2023] Open
Abstract
Huwentoxin-IV (HwTx-IV) is a 35-residue neurotoxin peptide with potential application as a novel analgesic. It is a member of the inhibitory cystine knot (ICK) peptide family, characterised by a compact globular structure maintained by three intramolecular disulfide bonds. Here we describe a novel strategy for producing non-tagged, fully folded ICK-toxin in a bacterial system. HwTx-IV was expressed as a cleavable fusion to small ubiquitin-related modifier (SUMO) in the cytoplasm of the SHuffle T7 Express lysY Escherichia coli strain, which allows cytosolic disulfide bond formation. Purification by IMAC with selective elution of monomeric SUMO fusion followed by proteolytic cleavage and polishing chromatographic steps yielded pure homogeneous toxin. Recombinant HwTx-IV is produced with a C-terminal acid, whereas the native peptide is C-terminally amidated. HwTx-IV(acid) inhibited Nav1.7 in a dose dependent manner (IC50 = 463-727 nM). In comparison to HwTx-IV(amide) (IC50 = 11 ± 3 nM), the carboxylate was ~50 fold less potent on Nav1.7, which highlights the impact of the C-terminus. As the amide bond of an additional amino acid may mimic the carboxamide, we expressed the glycine-extended analogue HwTx-IV(G36)(acid) in the SUMO/SHuffle system. The peptide was approximately three fold more potent on Nav1.7 in comparison to HwTx-IV(acid) (IC50 = 190 nM). In conclusion, we have established a novel system for expression and purification of fully folded and active HwTx-IV(acid) in bacteria, which could be applicable to other structurally complex and cysteine rich peptides. Furthermore, we discovered that glycine extension of HwTx-IV(acid) restores some of the potency of the native carboxamide. This finding may also apply to other C-terminally amidated peptides produced recombinantly.
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Affiliation(s)
- Isabelle Sermadiras
- Antibody Discovery and Protein Engineering, Research, MedImmune, Cambridge, United Kingdom
- * E-mail:
| | - Jefferson Revell
- Antibody Discovery and Protein Engineering, Research, MedImmune, Cambridge, United Kingdom
| | - John E. Linley
- Neuroscience in vitro Biology, Research, MedImmune, Cambridge, United Kingdom
| | - Alan Sandercock
- Antibody Discovery and Protein Engineering, Research, MedImmune, Cambridge, United Kingdom
| | - Peter Ravn
- Antibody Discovery and Protein Engineering, Research, MedImmune, Cambridge, United Kingdom
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Quick K, Zhao J, Eijkelkamp N, Linley JE, Rugiero F, Cox JJ, Raouf R, Gringhuis M, Sexton JE, Abramowitz J, Taylor R, Forge A, Ashmore J, Kirkwood N, Kros CJ, Richardson GP, Freichel M, Flockerzi V, Birnbaumer L, Wood JN. TRPC3 and TRPC6 are essential for normal mechanotransduction in subsets of sensory neurons and cochlear hair cells. Open Biol 2013; 2:120068. [PMID: 22724068 PMCID: PMC3376737 DOI: 10.1098/rsob.120068] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 04/16/2012] [Indexed: 12/21/2022] Open
Abstract
Transient receptor potential (TRP) channels TRPC3 and TRPC6 are expressed in both sensory neurons and cochlear hair cells. Deletion of TRPC3 or TRPC6 in mice caused no behavioural phenotype, although loss of TRPC3 caused a shift of rapidly adapting (RA) mechanosensitive currents to intermediate-adapting currents in dorsal root ganglion sensory neurons. Deletion of both TRPC3 and TRPC6 caused deficits in light touch and silenced half of small-diameter sensory neurons expressing mechanically activated RA currents. Double TRPC3/TRPC6 knock-out mice also showed hearing impairment, vestibular deficits and defective auditory brain stem responses to high-frequency sounds. Basal, but not apical, cochlear outer hair cells lost more than 75 per cent of their responses to mechanical stimulation. FM1-43-sensitive mechanically gated currents were induced when TRPC3 and TRPC6 were co-expressed in sensory neuron cell lines. TRPC3 and TRPC6 are thus required for the normal function of cells involved in touch and hearing, and are potential components of mechanotransducing complexes.
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Affiliation(s)
- Kathryn Quick
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
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Revell JD, Lund PE, Linley JE, Metcalfe J, Burmeister N, Sridharan S, Jones C, Jermutus L, Bednarek MA. Potency optimization of Huwentoxin-IV on hNav1.7: a neurotoxin TTX-S sodium-channel antagonist from the venom of the Chinese bird-eating spider Selenocosmia huwena. Peptides 2013; 44:40-6. [PMID: 23523779 DOI: 10.1016/j.peptides.2013.03.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 03/06/2013] [Accepted: 03/06/2013] [Indexed: 11/23/2022]
Abstract
The spider venom peptide Huwentoxin-IV (HwTx-IV) 1 is a potent antagonist of hNav1.7 (IC50 determined herein as 17 ± 2 nM). Nav1.7 is a voltage-gated sodium channel involved in the generation and conduction of neuropathic and nociceptive pain signals. We prepared a number of HwTx-IV analogs as part of a structure-function study into Nav1.7 antagonism. The inhibitory potency of these analogs was determined by automated electrophysiology and is reported herein. In particular, the native residues Glu(1), Glu(4), Phe(6) and Tyr(33) were revealed as important activity modulators and several peptides bearing mutations in these positions showed significantly increased potency on hNav1.7 while maintaining the original selectivity profile of the wild-type peptide 1 on hNav1.5. Peptide 47 (Gly(1), Gly(4), Trp(33)-HwTx) demonstrated the largest potency increase on hNav1.7 (IC50 0.4 ± 0.1 nM).
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Cregg R, Laguda B, Werdehausen R, Cox JJ, Linley JE, Ramirez JD, Bodi I, Markiewicz M, Howell KJ, Chen YC, Agnew K, Houlden H, Lunn MP, Bennett DLH, Wood JN, Kinali M. Novel mutations mapping to the fourth sodium channel domain of Nav1.7 result in variable clinical manifestations of primary erythromelalgia. Neuromolecular Med 2013; 15:265-78. [PMID: 23292638 PMCID: PMC3650253 DOI: 10.1007/s12017-012-8216-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 12/14/2012] [Indexed: 01/01/2023]
Abstract
We identified and clinically investigated two patients with primary erythromelalgia mutations (PEM), which are the first reported to map to the fourth domain of Nav1.7 (DIV). The identified mutations (A1746G and W1538R) were cloned and transfected to cell cultures followed by electrophysiological analysis in whole-cell configuration. The investigated patients presented with PEM, while age of onset was very different (3 vs. 61 years of age). Electrophysiological characterization revealed that the early onset A1746G mutation leads to a marked hyperpolarizing shift in voltage dependence of steady-state activation, larger window currents, faster activation kinetics (time-to-peak current) and recovery from steady-state inactivation compared to wild-type Nav1.7, indicating a pronounced gain-of-function. Furthermore, we found a hyperpolarizing shift in voltage dependence of slow inactivation, which is another feature commonly found in Nav1.7 mutations associated with PEM. In silico neuron simulation revealed reduced firing thresholds and increased repetitive firing, both indicating hyperexcitability. The late-onset W1538R mutation also revealed gain-of-function properties, although to a lesser extent. Our findings demonstrate that mutations encoding for DIV of Nav1.7 can not only be linked to congenital insensitivity to pain or paroxysmal extreme pain disorder but can also be causative of PEM, if voltage dependency of channel activation is affected. This supports the view that the degree of biophysical property changes caused by a mutation may have an impact on age of clinical manifestation of PEM. In summary, these findings extent the genotype-phenotype correlation profile for SCN9A and highlight a new region of Nav1.7 that is implicated in PEM.
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Affiliation(s)
- Roman Cregg
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, UCL, Gower Street, London, WC1E 6BT UK
- UCL Centre for Anaesthesia, Critical Care and Pain Medicine, London, UK
| | - Bisola Laguda
- Department of Paediatric Dermatology, Chelsea and Westminster Hospital, London, UK
| | - Robert Werdehausen
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, UCL, Gower Street, London, WC1E 6BT UK
- Department of Anesthesiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - James J. Cox
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, UCL, Gower Street, London, WC1E 6BT UK
| | - John E. Linley
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, UCL, Gower Street, London, WC1E 6BT UK
| | - Juan D. Ramirez
- Neurorestoration Group, CARD, King’s College London, Guy’s Campus, London, UK
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Istvan Bodi
- Department of Clinical Neuropathology, King’s College Hospital, London, UK
| | | | - Kevin J. Howell
- Centre for Rheumatology and Connective Tissue Disease, UCL Division of Medicine, Royal Free Campus, London, UK
| | - Ya-Chun Chen
- Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, UK
| | - Karen Agnew
- Department of Paediatric Dermatology, Chelsea and Westminster Hospital, London, UK
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Michael P. Lunn
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - David L. H. Bennett
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - John N. Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, UCL, Gower Street, London, WC1E 6BT UK
| | - Maria Kinali
- Department of Paediatric Neurology, Chelsea and Westminster Hospital, London, UK
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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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11
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Abstract
M-type (Kv7, KCNQ) K(+) channels control the resting membrane potential of many neurons, including peripheral nociceptive sensory neurons. Several M channel enhancers were suggested as prospective analgesics, and targeting M channels specifically in peripheral nociceptors is a plausible strategy for peripheral analgesia. However, receptor-induced inhibition of M channels in nociceptors is often observed in inflammation and may contribute to inflammatory pain. Such inhibition is predominantly mediated by phospholipase C. We investigated four M channel enhancers (retigabine, flupirtine, zinc pyrithione and H(2)O(2)) for their ability to overcome M channel inhibition via two phospholipase C-mediated mechanisms, namely depletion of membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)) and a rise in intracellular Ca(2+) (an action mediated by calmodulin). Data from overexpressed Kv7.2/Kv7.3 heteromers and native M currents in dorsal root ganglion neurons suggest the following conclusions. (i) All enhancers had a dual effect on M channel activity, a negative shift in voltage dependence and an increase of the maximal current at saturating voltages. The enhancers differed in their efficacy to produce these effects. (ii) Both PIP(2) depletion and Ca(2+)/calmodulin strongly reduced the M current amplitude; however, at voltages near the threshold for M channel activation (-60 mV) all enhancers were able to restore M channel activity to a control level or above, while at saturating voltages the effects were more variable. (iii) Receptor-mediated inhibition of M current in nociceptive dorsal root ganglion neurons did not reduce the efficacy of retigabine or flupirtine to hyperpolarize the resting membrane potential. In conclusion, we show that all four M channel enhancers tested could overcome both PIP(2) and Ca(2+)-calmodulin-induced inhibition of Kv7.2/7.3 at voltages close to the threshold for action potential firing (-60 mV) but generally had reduced efficacy at a saturating voltage (0 mV). We suggest that the efficacy of an M channel enhancer to shift the voltage dependence of activation may be most important for rescuing M channel function in sensory neurons innervating inflamed tissue.
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Affiliation(s)
- John E Linley
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
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Al-Hazza A, Linley JE, Aziz Q, MacLennan KA, Hunter M, Sandle GI. Potential role of reduced basolateral potassium (IKCa3.1) channel expression in the pathogenesis of diarrhoea in ulcerative colitis. J Pathol 2011; 226:463-70. [DOI: 10.1002/path.2994] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/09/2011] [Accepted: 08/19/2011] [Indexed: 11/06/2022]
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Liu B, Linley JE, Du X, Zhang X, Ooi L, Zhang H, Gamper N. The acute nociceptive signals induced by bradykinin in rat sensory neurons are mediated by inhibition of M-type K+ channels and activation of Ca2+-activated Cl- channels. J Clin Invest 2010; 120:1240-52. [PMID: 20335661 DOI: 10.1172/jci41084] [Citation(s) in RCA: 230] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 01/13/2010] [Indexed: 12/30/2022] Open
Abstract
Bradykinin (BK) is an inflammatory mediator and one of the most potent endogenous pain-inducing substances. When released at sites of tissue damage or inflammation, or applied exogenously, BK produces acute spontaneous pain and causes hyperalgesia (increased sensitivity to potentially painful stimuli). The mechanisms underlying spontaneous pain induced by BK are poorly understood. Here we report that in small nociceptive neurons from rat dorsal root ganglia, BK, acting through its B2 receptors, PLC, and release of calcium from intracellular stores, robustly inhibits M-type K+ channels and opens Ca2+-activated Cl- channels (CaCCs) encoded by Tmem16a (also known as Ano1). Summation of these two effects accounted for the depolarization and increase in AP firing induced by BK in DRG neurons. Local injection of inhibitors of CaCC and specific M-channel openers both strongly attenuated the nociceptive effect of local injections of BK in rats. These results provide a framework for understanding spontaneous inflammatory pain and may suggest new drug targets for treatment of such pain.
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Affiliation(s)
- Boyi Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
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Linley JE, Rose K, Ooi L, Gamper N. Understanding inflammatory pain: ion channels contributing to acute and chronic nociception. Pflugers Arch 2010; 459:657-69. [DOI: 10.1007/s00424-010-0784-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 01/04/2010] [Accepted: 01/06/2010] [Indexed: 02/06/2023]
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Linley JE, Liu B, Ooi L, Zhang H, Gamper N. Substance P and Bradykinin Activate Alternative Gq/11-Coupled Signalling Cascades and Impose Opposite Effects on M Current in DRG Neurons. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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16
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Ooi L, Rose KE, Linley JE, Mucha M, Wood IC, Gamper N. Regulation Of Kcnq2/3 Channels By The Transcriptional Repressor REST In Nociception. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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17
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Linley JE, Gamper N. Can Pharmacological Openers Of M-type Potassium Channels Overcome Receptor-mediated Channel Inhibition? Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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18
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Bowley KA, Linley JE, Robins GG, Kopanati S, Hunter M, Sandle GI. Role of protein kinase C in aldosterone-induced non-genomic inhibition of basolateral potassium channels in human colonic crypts. J Steroid Biochem Mol Biol 2007; 104:45-52. [PMID: 17184988 DOI: 10.1016/j.jsbmb.2006.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 10/05/2006] [Indexed: 11/26/2022]
Abstract
Aldosterone produces rapid, non-genomic, inhibition of basolateral intermediate conductance K(+) (IK(Ca)) channels in human colonic crypt cells but the intracellular second messengers involved are unclear. We therefore evaluated the role of protein kinase C (PKC) in aldosterone's non-genomic inhibitory effect on basolateral IK(Ca) channels in crypt cells from normal human sigmoid colon. Patch clamp studies revealed that in cell-attached patches, IK(Ca) channel activity decreased progressively to 38+/-8% (P<0.001) of the basal value 10 min after the addition of 1 nmol/L aldosterone, and decreased further to 23+/-6% (P<0.02) of the basal value 5 min after increasing the aldosterone concentration to 10 nmol/L. Pre-incubation of crypts with 1 micromol/L chelerythrine chloride or 1 micromol/L Gö 6976 (PKC inhibitors) prevented the inhibitory effect of aldosterone. Conversely, channel activity decreased to 60+/-9% (P<0.02) of the basal value 10 min after the addition of 500 nmol/L PMA (a PKC activator), whereas 4alpha-PMA (an inactive ester) had no effect. When aldosterone (10 nmol/L) and PMA were added together, IK(Ca) channel activity was inhibited to the same extent as with aldosterone alone. These results indicate that aldosterone's non-genomic inhibitory effect on the macroscopic basolateral K(+) conductance in human colonic crypts reflects PKC-mediated inhibition of IK(Ca) channels.
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Affiliation(s)
- Kate A Bowley
- Institute for Molecular Medicine, St. James's University Hospital, Leeds LS9 7TF, UK
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Sandle GI, Perry MD, Mathialahan T, Linley JE, Robinson P, Hunter M, MacLennan KA. Altered cryptal expression of luminal potassium (BK) channels in ulcerative colitis. J Pathol 2007; 212:66-73. [PMID: 17405186 DOI: 10.1002/path.2159] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Decreased sodium (Na(+)), chloride (Cl(-)), and water absorption, and increased potassium (K(+)) secretion, contribute to the pathogenesis of diarrhoea in ulcerative colitis. The cellular abnormalities underlying decreased Na(+) and Cl(-) absorption are becoming clearer, but the mechanism of increased K(+) secretion is unknown. Human colon is normally a K(+) secretory epithelium, making it likely that K(+) channels are expressed in the luminal (apical) membrane. Based on the assumption that these K(+) channels resembled the high conductance luminal K(+) (BK) channels previously identified in rat colon, we used molecular and patch clamp recording techniques to evaluate BK channel expression in normal and inflamed human colon, and the distribution and characteristics of these channels in normal colon. In normal colon, BK channel alpha-subunit protein was immunolocalized to surface cells and upper crypt cells. By contrast, in ulcerative colitis, although BK channel alpha-subunit protein expression was unchanged in surface cells, it extended along the entire crypt irrespective of whether the disease was active or quiescent. BK channel alpha-subunit protein and mRNA expression (evaluated by western blotting and real-time PCR, respectively) were similar in the normal ascending and sigmoid colon. Of the four possible beta-subunits (beta(1-4)), the beta(1)- and beta(3)-subunits were dominant. Voltage-dependent, barium-inhibitable, luminal K(+) channels with a unitary conductance of 214 pS were identified at low abundance in the luminal membrane of surface cells around the openings of sigmoid colonic crypts. We conclude that increased faecal K(+) losses in ulcerative colitis, and possibly other diseases associated with altered colonic K(+) transport, may reflect wider expression of luminal BK channels along the crypt axis.
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Affiliation(s)
- G I Sandle
- Institute for Molecular Medicine, St James's University Hospital, Leeds, UK.
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Linley JE, Simmons NL, Gray MA. Extracellular zinc stimulates a calcium-activated chloride conductance through mobilisation of intracellular calcium in renal inner medullary collecting duct cells. Pflugers Arch 2006; 453:487-95. [PMID: 17021797 DOI: 10.1007/s00424-006-0139-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 07/13/2006] [Accepted: 07/18/2006] [Indexed: 10/24/2022]
Abstract
We have used the perforated patch clamp and fura-2 fluorescence techniques to study the effect of extracellular Zn(2+) on whole-cell Ca(2+)-activated Cl(-) currents (I (CLCA)) in mouse inner medullary collecting duct cells (mIMCD-3). I (CLCA) was spontaneously active in 74% of cells under basal conditions and displayed time and voltage-independent kinetics and an outwardly rectifying current/voltage relationship (I/V). Addition of zinc chloride (10-400 microM) to the bathing solution resulted in a dose-dependent increase in I (CLCA) with little change in Cl(-) selectivity or biophysical characteristics, whereas gadolinium chloride (30 microM) and lanthanum chloride (100 microM) had no significant effect on the whole-cell current. Using fura-2-loaded mIMCD-3 cells, extracellular Zn(2+) (400 microM) stimulated an increase in intracellular Ca(2+) to an elevated plateau. The Zn(2+)-stimulated [Ca(2+)](i) increase was inhibited by thapsigargin (200 nM), the IP(3) receptor antagonist 2-aminoethoxydiphenyl borate (10 microM) and removal of bath Ca(2+). Pre-exposure to Zn(2+) (400 microM) markedly attenuated the ATP (100 microM)-stimulated [Ca(2+)](i) increase. These data are consistent with the hypothesis that extracellular Zn(2+) stimulates an increase in [Ca(2+)](i) by a release of calcium from thapsigargin/IP(3) sensitive stores. A possible physiological role for a divalent metal ion receptor, distinct from the extracellular Ca(2+)-sensing receptor, in IMCD cells is discussed.
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Affiliation(s)
- J E Linley
- Institute of Cell and Molecular Biosciences, University Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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