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Pandey Y, Dondapati SK, Kubick S. Enriched cell-free and cell-based native membrane derived vesicles (nMV) enabling rapid in-vitro electrophysiological analysis of the voltage-gated sodium channel 1.5. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184144. [PMID: 36889502 DOI: 10.1016/j.bbamem.2023.184144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/10/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023]
Abstract
Here, we demonstrate the utility of native membrane derived vesicles (nMVs) as tools for expeditious electrophysiological analysis of membrane proteins. We used a cell-free (CF) and a cell-based (CB) approach for preparing protein-enriched nMVs. We utilized the Chinese Hamster Ovary (CHO) lysate-based cell-free protein synthesis (CFPS) system to enrich ER-derived microsomes in the lysate with the primary human cardiac voltage-gated sodium channel 1.5 (hNaV1.5; SCN5A) in 3 h. Subsequently, CB-nMVs were isolated from fractions of nitrogen-cavitated CHO cells overexpressing the hNaV1.5. In an integrative approach, nMVs were micro-transplanted into Xenopus laevis oocytes. CB-nMVs expressed native lidocaine-sensitive hNaV1.5 currents within 24 h; CF-nMVs did not elicit any response. Both the CB- and CF-nMV preparations evoked single-channel activity on the planar lipid bilayer while retaining sensitivity to lidocaine application. Our findings suggest a high usability of the quick-synthesis CF-nMVs and maintenance-free CB-nMVs as ready-to-use tools for in-vitro analysis of electrogenic membrane proteins and large, voltage-gated ion channels.
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Affiliation(s)
- Yogesh Pandey
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; Institut für Biochemie und Biologie, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam OT Golm, Germany
| | - Srujan Kumar Dondapati
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany.
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, 14476 Potsdam, Germany; Technische Universität Berlin, Institute of Biotechnology, Straße des 17. Juni 135, 10623 Berlin, Germany; Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany; Faculty of Health Science, Joint Faculty of the Brandenburg University of Technology Cottbus-Senftenberg, the Brandenburg Medical School Theodor Fontane and the University of Potsdam, Germany
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Screening an In-House Isoquinoline Alkaloids Library for New Blockers of Voltage-Gated Na+ Channels Using Voltage Sensor Fluorescent Probes: Hits and Biases. Molecules 2022; 27:molecules27134133. [PMID: 35807390 PMCID: PMC9268414 DOI: 10.3390/molecules27134133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 12/04/2022] Open
Abstract
Voltage-gated Na+ (NaV) channels are significant therapeutic targets for the treatment of cardiac and neurological disorders, thus promoting the search for novel NaV channel ligands. With the objective of discovering new blockers of NaV channel ligands, we screened an In-House vegetal alkaloid library using fluorescence cell-based assays. We screened 62 isoquinoline alkaloids (IA) for their ability to decrease the FRET signal of voltage sensor probes (VSP), which were induced by the activation of NaV channels with batrachotoxin (BTX) in GH3b6 cells. This led to the selection of five IA: liriodenine, oxostephanine, thalmiculine, protopine, and bebeerine, inhibiting the BTX-induced VSP signal with micromolar IC50. These five alkaloids were then assayed using the Na+ fluorescent probe ANG-2 and the patch-clamp technique. Only oxostephanine and liriodenine were able to inhibit the BTX-induced ANG-2 signal in HEK293-hNaV1.3 cells. Indeed, liriodenine and oxostephanine decreased the effects of BTX on Na+ currents elicited by the hNaV1.3 channel, suggesting that conformation change induced by BTX binding could induce a bias in fluorescent assays. However, among the five IA selected in the VSP assay, only bebeerine exhibited strong inhibitory effects against Na+ currents elicited by the hNav1.2 and hNav1.6 channels, with IC50 values below 10 µM. So far, bebeerine is the first BBIQ to have been reported to block NaV channels, with promising therapeutical applications.
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Horishita T, Ogata Y, Horishita R, Fukui R, Moriwaki K, Ueno S, Yanagihara N, Uezono Y, Sudo Y, Minami K. Carvacrol inhibits the neuronal voltage-gated sodium channels Na v1.2, Na v1.6, Na v1.3, Na v1.7, and Na v1.8 expressed in Xenopus oocytes with different potencies. J Pharmacol Sci 2020; 142:140-147. [PMID: 31982332 DOI: 10.1016/j.jphs.2019.12.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/07/2019] [Accepted: 12/26/2019] [Indexed: 12/19/2022] Open
Abstract
Carvacrol is the predominant monoterpene in essential oils from many aromatic plants. Several animal studies showing analgesic effects of carvacrol indicate potential of carvacrol as a new medication for patients with refractory pain. Voltage-gated sodium channels (Nav) are thought to have crucial roles in the development of inflammatory and neuropathic pain, but there is limited information about whether the analgesic mechanism of carvacrol involves Nav. We used whole-cell, two-electrode, voltage-clamp techniques to examine the effects of carvacrol on sodium currents in Xenopus oocytes expressing α subunits of Nav1.2, Nav1.3, Nav1.6, Nav1.7, and Nav1.8. Carvacrol dose-dependently suppressed sodium currents at a holding potential that induced half-maximal current. The half-maximal inhibitory concentration values for Nav1.2, Nav1.3, Nav1.6, Nav1.7, and Nav1.8 were 233, 526, 215, 367, and 824 μmol/L, respectively, indicating that carvacrol had more potent inhibitory effects towards Nav1.2 and Nav1.6 than Nav1.3, Nav1.7, and Nav1.8. Gating analysis showed a depolarizing shift of the activation curve and a hyperpolarizing shift of the inactivation curve in all five α subunits following carvacrol treatment. Furthermore, carvacrol exhibits a use-dependent block for all five α Nav subunits. These findings provide a better understanding of the mechanisms associated with the analgesic effect of carvacrol.
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Affiliation(s)
- Takafumi Horishita
- Department of Anesthesiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
| | - Yuichi Ogata
- Department of Anesthesiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Reiko Horishita
- Department of Anesthesiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Ryo Fukui
- Department of Anesthesiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kuniaki Moriwaki
- Department of Anesthesiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Susumu Ueno
- Department of Occupational Toxicology, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Nobuyuki Yanagihara
- Laboratory of Pharmacology, Faculty of Food and Nutrition, Kyushu Nutrition Welfare University, Kitakyushu, Japan
| | - Yasuhito Uezono
- Cancer Pathophysiology Division, National Cancer Center Research Institute, Tokyo, Japan
| | - Yuka Sudo
- Department of Molecular Pathology & Metabolic Disease, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Chiba, Japan
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Han D, Xue X, Yan Y, Li G. Dysfunctional Cav1.2 channel in Timothy syndrome, from cell to bedside. Exp Biol Med (Maywood) 2019; 244:960-971. [PMID: 31324123 DOI: 10.1177/1535370219863149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Timothy syndrome is a rare disorder caused by CACNA1C gene mutations and characterized by multi-organ system dysfunctions, including ventricular arrhythmias, syndactyly, dysmorphic facial features, intermittent hypoglycemia, immunodeficiency, developmental delay, and autism. Because of the low morbidity and high mortality at a young age, it remains a huge challenge to establish a diagnosis and treatment system to manage Timothy syndrome patients. Here, we aim to provide a detailed review of Timothy syndrome, discuss the mechanisms underlying dysfunctional Cav1.2 due to CACNA1C mutations, and provide some new emerging evidences in treating Timothy syndrome from cell to bedside, promoting the management of this rare disease. Impact statement The knowledge of Timothy syndrome (TS) caused by dysfunctional Cav1.2 channel due to CACNA1C mutations is rapidly evolving as novel technologies of electrophysiology are introduced and our understanding of the mechanisms of TS develops. In this review, we focus on the TS-related dysfunctional Cav1.2 and the underlying mechanisms. We update TS-related CACNA1C mutations in a precise way over the past 20 years and summarize all reported TS patients based on their clinical presentations and molecular mechanisms, respectively. We hope this review will provide a new comprehensive way to better understand the electrophysiological mechanisms underlying TS from cell to bedside, promoting the management of TS in practice.
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Affiliation(s)
- Dan Han
- 1 Department of Cardiology, the First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, P. R. China.,2 Department of Cardiovascular Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, P.R. China*These authors contributed equally to this work and should be considered to share first authorship
| | - Xiaolin Xue
- 1 Department of Cardiology, the First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, P. R. China
| | - Yang Yan
- 2 Department of Cardiovascular Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, P.R. China*These authors contributed equally to this work and should be considered to share first authorship
| | - Guoliang Li
- 1 Department of Cardiology, the First Affiliated Hospital of Xi'an Jiaotong University, Shaanxi 710061, P. R. China
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Sun S, Jia Q, Zenova AY, Wilson MS, Chowdhury S, Focken T, Li J, Decker S, Grimwood ME, Andrez JC, Hemeon I, Sheng T, Chen CA, White A, Hackos DH, Deng L, Bankar G, Khakh K, Chang E, Kwan R, Lin S, Nelkenbrecher K, Sellers BD, DiPasquale AG, Chang J, Pang J, Sojo L, Lindgren A, Waldbrook M, Xie Z, Young C, Johnson JP, Robinette CL, Cohen CJ, Safina BS, Sutherlin DP, Ortwine DF, Dehnhardt CM. Identification of Selective Acyl Sulfonamide–Cycloalkylether Inhibitors of the Voltage-Gated Sodium Channel (NaV) 1.7 with Potent Analgesic Activity. J Med Chem 2018; 62:908-927. [DOI: 10.1021/acs.jmedchem.8b01621] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Shaoyi Sun
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Qi Jia
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Alla Y. Zenova
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Michael S. Wilson
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Sultan Chowdhury
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Thilo Focken
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Jun Li
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Shannon Decker
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Michael E. Grimwood
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Jean-Christophe Andrez
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Ivan Hemeon
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Tao Sheng
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Chien-An Chen
- ChemPartner, Building No. 5, 998 Halei Road, Zhangjiang Hi-Tech Park, Pudong New Area, Shanghai 201203, P. R. China
| | - Andy White
- ChemPartner, Building No. 5, 998 Halei Road, Zhangjiang Hi-Tech Park, Pudong New Area, Shanghai 201203, P. R. China
| | - David H. Hackos
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Lunbin Deng
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Girish Bankar
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Kuldip Khakh
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Elaine Chang
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Rainbow Kwan
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Sophia Lin
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Karen Nelkenbrecher
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Benjamin D. Sellers
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Antonio G. DiPasquale
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Jae Chang
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Jodie Pang
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Luis Sojo
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Andrea Lindgren
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Matthew Waldbrook
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Zhiwei Xie
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Clint Young
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - James P. Johnson
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - C. Lee Robinette
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Charles J. Cohen
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
| | - Brian S. Safina
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Daniel P. Sutherlin
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Daniel F. Ortwine
- Genentech Inc., 1 DNA Way, South San Francisco, California 94080-4990, United States
| | - Christoph M. Dehnhardt
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, British Columbia V5G 4W8, Canada
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Yang Z, Tan Q, Cheng D, Zhang L, Zhang J, Gu EW, Fang W, Lu X, Liu X. The Changes of Intrinsic Excitability of Pyramidal Neurons in Anterior Cingulate Cortex in Neuropathic Pain. Front Cell Neurosci 2018; 12:436. [PMID: 30519160 PMCID: PMC6258991 DOI: 10.3389/fncel.2018.00436] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/05/2018] [Indexed: 12/13/2022] Open
Abstract
To find satisfactory treatment strategies for neuropathic pain syndromes, the cellular mechanisms should be illuminated. Central sensitization is a generator of pain hypersensitivity, and is mainly reflected in neuronal hyperexcitability in pain pathway. Neuronal excitability depends on two components, the synaptic inputs and the intrinsic excitability. Previous studies have focused on the synaptic plasticity in different forms of pain. But little is known about the changes of neuronal intrinsic excitability in neuropathic pain. To address this question, whole-cell patch clamp recordings were performed to study the synaptic transmission and neuronal intrinsic excitability 1 week after spared nerve injury (SNI) or sham operation in male C57BL/6J mice. We found increased spontaneous excitatory postsynaptic currents (sEPSC) frequency in layer II/III pyramidal neurons of anterior cingulate cortex (ACC) from mice with neuropathic pain. Elevated intrinsic excitability of these neurons after nerve injury was also picked up, which was reflected in gain of input-output curve, inter-spike interval (ISI), spike threshold and Refractory period (RP). Besides firing rate related to neuronal intrinsic excitability, spike timing also plays an important role in neural information processing. The precision of spike timing measured by standard deviation of spike timing (SDST) was decreased in neuropathic pain state. The electrophysiological studies revealed the elevated intrinsic excitation in layer II/III pyramidal neurons of ACC in mice with neuropathic pain, which might contribute to central excitation.
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Affiliation(s)
- Zhilai Yang
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Qilian Tan
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Dan Cheng
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Lei Zhang
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Jiqian Zhang
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Er-Wei Gu
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Weiping Fang
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Xianfu Lu
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
| | - Xuesheng Liu
- Department of Anesthesiology, First Affiliated Hospital, Anhui Medical University, Hefei, China
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Han D, Tan H, Sun C, Li G. Dysfunctional Nav1.5 channels due to SCN5A mutations. Exp Biol Med (Maywood) 2018; 243:852-863. [PMID: 29806494 DOI: 10.1177/1535370218777972] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The voltage-gated sodium channel 1.5 (Nav1.5), encoded by the SCN5A gene, is responsible for the rising phase of the action potential of cardiomyocytes. The sodium current mediated by Nav1.5 consists of peak and late components (INa-P and INa-L). Mutant Nav1.5 causes alterations in the peak and late sodium current and is associated with an increasingly wide range of congenital arrhythmias. More than 400 mutations have been identified in the SCN5A gene. Although the mechanisms of SCN5A mutations leading to a variety of arrhythmias can be classified according to the alteration of INa-P and INa-L as gain-of-function, loss-of-function and both, few researchers have summarized the mechanisms in this way before. In this review article, we aim to review the mechanisms underlying dysfunctional Nav1.5 due to SCN5A mutations and to provide some new insights into further approaches in the treatment of arrhythmias. Impact statement The field of ion channelopathy caused by dysfunctional Nav1.5 due to SCN5A mutations is rapidly evolving as novel technologies of electrophysiology are introduced and our understanding of the mechanisms of various arrhythmias develops. In this review, we focus on the dysfunctional Nav1.5 related to arrhythmias and the underlying mechanisms. We update SCN5A mutations in a precise way since 2013 and presents novel classifications of SCN5A mutations responsible for the dysfunction of the peak (INa-P) and late (INa-L) sodium channels based on their phenotypes, including loss-, gain-, and coexistence of gain- and loss-of function mutations in INa-P, INa-L, respectively. We hope this review will provide a new comprehensive way to better understand the electrophysiological mechanisms underlying arrhythmias from cell to bedside, promoting the management of various arrhythmias in practice.
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Affiliation(s)
- Dan Han
- 1 Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
| | - Hui Tan
- 2 Department of Respiratory Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
| | - Chaofeng Sun
- 1 Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
| | - Guoliang Li
- 1 Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, P.R. China
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Neurosteroids Allopregnanolone Sulfate and Pregnanolone Sulfate Have Diverse Effect on the α Subunit of the Neuronal Voltage-gated Sodium Channels Nav1.2, Nav1.6, Nav1.7, and Nav1.8 Expressed in Xenopus Oocytes. Anesthesiology 2014; 121:620-31. [DOI: 10.1097/aln.0000000000000296] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract
Background:
The neurosteroids allopregnanolone and pregnanolone are potent positive modulators of γ-aminobutyric acid type A receptors. Antinociceptive effects of allopregnanolone have attracted much attention because recent reports have indicated the potential of allopregnanolone as a therapeutic agent for refractory pain. However, the analgesic mechanisms of allopregnanolone are still unclear. Voltage-gated sodium channels (Nav) are thought to play important roles in inflammatory and neuropathic pain, but there have been few investigations on the effects of allopregnanolone on sodium channels.
Methods:
Using voltage-clamp techniques, the effects of allopregnanolone sulfate (APAS) and pregnanolone sulfate (PAS) on sodium current were examined in Xenopus oocytes expressing Nav1.2, Nav1.6, Nav1.7, and Nav1.8 α subunits.
Results:
APAS suppressed sodium currents of Nav1.2, Nav1.6, and Nav1.7 at a holding potential causing half-maximal current in a concentration-dependent manner, whereas it markedly enhanced sodium current of Nav1.8 at a holding potential causing maximal current. Half-maximal inhibitory concentration values for Nav1.2, Nav1.6, and Nav1.7 were 12 ± 4 (n = 6), 41 ± 2 (n = 7), and 131 ± 15 (n = 5) μmol/l (mean ± SEM), respectively. The effects of PAS were lower than those of APAS. From gating analysis, two compounds increased inactivation of all α subunits, while they showed different actions on activation of each α subunit. Moreover, two compounds showed a use-dependent block on Nav1.2, Nav1.6, and Nav1.7.
Conclusion:
APAS and PAS have diverse effects on sodium currents in oocytes expressing four α subunits. APAS inhibited the sodium currents of Nav1.2 most strongly.
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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: 248] [Impact Index Per Article: 20.7] [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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Kam YL, Back SK, Kang B, Kim YY, Kim HJ, Rhim H, Nah SY, Chung JM, Kim DH, Choi JS, Na HS, Choo HYP. HYP-1, a novel diamide compound, relieves inflammatory and neuropathic pain in rats. Pharmacol Biochem Behav 2012; 103:33-42. [DOI: 10.1016/j.pbb.2012.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 06/30/2012] [Accepted: 07/23/2012] [Indexed: 01/30/2023]
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Lim J, Taoka B, Otte RD, Spencer K, Dinsmore CJ, Altman MD, Chan G, Rosenstein C, Sharma S, Su HP, Szewczak AA, Xu L, Yin H, Zugay-Murphy J, Marshall CG, Young JR. Discovery of 1-amino-5H-pyrido[4,3-b]indol-4-carboxamide inhibitors of Janus kinase 2 (JAK2) for the treatment of myeloproliferative disorders. J Med Chem 2011; 54:7334-49. [PMID: 21942426 DOI: 10.1021/jm200909u] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The JAK-STAT pathway mediates signaling by cytokines, which control survival, proliferation, and differentiation of a variety of cells. In recent years, a single point mutation (V617F) in the tyrosine kinase JAK2 was found to be present with a high incidence in myeloproliferative disorders (MPDs). This mutation led to hyperactivation of JAK2, cytokine-independent signaling, and subsequent activation of downstream signaling networks. The genetic, biological, and physiological evidence suggests that JAK2 inhibitors could be effective in treating MPDs. De novo design efforts of new scaffolds identified 1-amino-5H-pyrido[4,3-b]indol-4-carboxamides as a new viable lead series. Subsequent optimization of cell potency, metabolic stability, and off-target activities of the leads led to the discovery of 7-(2-aminopyrimidin-5-yl)-1-{[(1R)-1-cyclopropyl-2,2,2-trifluoroethyl]amino}-5H-pyrido[4,3-b]indole-4-carboxamide (65). Compound 65 is a potent, orally active inhibitor of JAK2 with excellent selectivity, PK profile, and in vivo efficacy in animal models.
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Affiliation(s)
- Jongwon Lim
- Department of Chemistry, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States.
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12
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Tyagarajan S, Chakravarty PK, Zhou B, Taylor B, Eid R, Fisher MH, Parsons WH, Wyvratt MJ, Lyons KA, Klatt T, Li X, Kumar S, Williams B, Felix J, Priest BT, Brochu RM, Warren V, Smith M, Garcia M, Kaczorowski GJ, Martin WJ, Abbadie C, McGowan E, Jochnowitz N, Weber A, Duffy JL. Discovery of a novel class of biphenyl pyrazole sodium channel blockers for treatment of neuropathic pain. Bioorg Med Chem Lett 2010; 20:7479-82. [PMID: 21106456 DOI: 10.1016/j.bmcl.2010.10.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 10/01/2010] [Accepted: 10/05/2010] [Indexed: 01/16/2023]
Abstract
A series of novel biphenyl pyrazole dicarboxamides were identified as potential sodium channel blockers for treatment of neuropathic pain. Compound 20 had outstanding efficacy in the Chung rat spinal nerve ligation (SNL) model of neuropathic pain.
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Affiliation(s)
- Sriram Tyagarajan
- Department of Medicinal Chemistry, Merck Research Laboratories, Rahway, NJ 07065, USA.
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13
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A-887826 is a structurally novel, potent and voltage-dependent Nav1.8 sodium channel blocker that attenuates neuropathic tactile allodynia in rats. Neuropharmacology 2010; 59:201-7. [DOI: 10.1016/j.neuropharm.2010.05.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 05/19/2010] [Accepted: 05/23/2010] [Indexed: 12/19/2022]
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14
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Lenkey N, Karoly R, Epresi N, Vizi E, Mike A. Binding of sodium channel inhibitors to hyperpolarized and depolarized conformations of the channel. Neuropharmacology 2010; 60:191-200. [PMID: 20713065 DOI: 10.1016/j.neuropharm.2010.08.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 07/23/2010] [Accepted: 08/07/2010] [Indexed: 12/13/2022]
Abstract
Sodium channels are inhibited by a chemically diverse group of compounds. In the last decade entirely new structural classes with superior properties have been discovered, and novel therapeutic uses of sodium channel inhibitors (SCIs) have been suggested. Many promising novel drug candidates have been described and characterized. Published structure-activity relationship studies, pharmacophore models, and mutagenesis studies seem to lag behind, dealing with only a limited group of inhibitor compounds. The abundance of novel compounds requires an organized comparison of drug potencies. The affinity of sodium channel inhibitors can vary typically ten- to thousand-fold depending on the voltage protocol; therefore comparison of electrophysiology data is difficult. In this study we describe a method for standardization of these data with the help of a simple model of state-dependence. We derived hyperpolarized (resting) and depolarized (generally termed "inactivated") state affinities for the studied drugs, which made the measurements comparable. We show a rank order of SCIs based on resting and inactivated affinity values. In an attempt to define basic chemical requirements for sodium channel inhibitor activity we investigated the dependence of both resting and inactivated state affinities on individual chemical descriptors. Lipophilicity (most often expressed by the logP value) is the single most important determinant of SCI potency. We investigated the independent impact of several other calculated chemical properties by standardizing drug potencies for logP values. By combining these two approaches: standardization of affinity values, and standardization of potencies, we concluded that while resting affinity is mostly determined by lipophilicity, inactivated state affinity is determined by a more complex interaction of chemical properties, including hydrogen bond acceptors, aromatic rings, and molecular weight.
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Affiliation(s)
- N Lenkey
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, P.O.B. 67, H-1450 Budapest, Hungary
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15
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Abstract
Drugs inhibiting voltage-gated sodium channels have long been used as analgesics, beginning with the use of local anaesthetics for sensory blockade and then with the discovery that Nav-blocking anticonvulsants also have benefit for pain therapy. These drugs were discovered without knowledge of their molecular target, using traditional pharmacological methods, and their clinical utility is limited by relatively narrow therapeutic windows. Until recently, attempts to develop improved inhibitors using modern molecular-targeted screening approaches have met with limited success. However, in the last few years there has been renewed activity following the discovery of human Nav1.7 mutations that cause striking insensitivity to pain. Together with recent advances in the technologies required to prosecute ion channels as drug targets, this has led to significant progress being made. This article reviews these developments and summarises current findings with these emerging new Nav inhibitors, highlighting some of the unanswered questions and the challenges that remain before they can be developed for clinical use.
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Affiliation(s)
- Jeffrey J Clare
- Cell-Based Assays Group, Millipore Corporation, St Charles, Missouri 63304, USA.
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16
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Fong T, Shearman L, Stribling D, Shu J, Lao J, Huang CR, Xiao J, Shen CP, Tyszkiewicz J, Strack A, DeMaula C, Hubert MF, Galijatovic-Idrizbegovic A, Owen R, Huber A, Lanning C. Pharmacological efficacy and safety profile of taranabant in preclinical species. Drug Dev Res 2009. [DOI: 10.1002/ddr.20311] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Singewald N, Chicchi GG, Thurner CC, Tsao KL, Spetea M, Schmidhammer H, Sreepathi HK, Ferraguti F, Singewald GM, Ebner K. Modulation of basal and stress-induced amygdaloid substance P release by the potent and selective NK1 receptor antagonist L-822429. J Neurochem 2008; 106:2476-88. [PMID: 18673452 DOI: 10.1111/j.1471-4159.2008.05596.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
It has been shown that anxiety and stress responses are modulated by substance P (SP) released within the amygdala. However, there is an important gap in our knowledge concerning the mechanisms regulating extracellular SP in this brain region. To study a possible self-regulating role of SP, we used a selective neurokinin-1 (NK1) receptor antagonist to investigate whether blockade of NK1 receptors results in altered basal and/or stress-evoked SP release in the medial amygdala (MeA), a critical brain area for a functional involvement of SP transmission in enhanced anxiety responses induced by stressor exposure. In vitro binding and functional receptor assays revealed that L-822429 represents a potent and selective rat NK1 receptor antagonist. Intra-amygdaloid administration of L-822429 via inverse microdialysis enhanced basal, but attenuated swim stress-induced SP release, while the low-affinity enantiomer of L-822429 had no effect. Using light and electron microscopy, synaptic contacts between SP-containing fibres and dendrites expressing NK1 receptors was demonstrated in the medial amygdala. Our findings suggest self-regulatory capacity of SP-mediated neurotransmission that differs in the effect on basal and stress-induced release of SP. Under basal conditions endogenous SP can serve as a signal that tonically inhibits its own release via a NK1 receptor-mediated negative feedback action, while under stress conditions SP release is further facilitated by activation of NK1 receptors, likely leading to high local levels of SP and activation of receptors to which SP binds with lower affinity.
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Affiliation(s)
- Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Innsbruck, Austria.
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18
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Kaczorowski GJ, McManus OB, Priest BT, Garcia ML. Ion channels as drug targets: the next GPCRs. ACTA ACUST UNITED AC 2008; 131:399-405. [PMID: 18411331 PMCID: PMC2346569 DOI: 10.1085/jgp.200709946] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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19
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Priest BT. On the Process of Finding Novel and Selective Sodium Channel Blockers for the Treatment of Diseases. TOPICS IN MEDICINAL CHEMISTRY 2008. [DOI: 10.1007/7355_2008_019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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20
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Weinglass AB, Köhler MG, Nketiah EO, Liu J, Schmalhofer W, Thomas A, Williams B, Beers L, Smith L, Hafey M, Bleasby K, Leone J, Tang YS, Braun M, Ujjainwalla F, McCann ME, Kaczorowski GJ, Garcia ML. Madin-Darby canine kidney II cells: a pharmacologically validated system for NPC1L1-mediated cholesterol uptake. Mol Pharmacol 2008; 73:1072-84. [PMID: 18187582 DOI: 10.1124/mol.107.043844] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Absorption of dietary cholesterol in the proximal region of the intestine is mediated by Niemann-Pick C1-like protein (NPC1L1) and is sensitive to the cholesterol absorption inhibitor ezetimibe (EZE). Although a correlation exists between EZE binding to NPC1L1 in vitro and efficacy in vivo, the precise nature of interaction(s) between NPC1L1, EZE, and cholesterol remain unclear. Here, we analyze the direct relationship between EZE analog binding to NPC1L1 and its influence on cholesterol influx in a novel in vitro system. Using the EZE analog [(3)H]AS, an assay that quantitatively measures the expression of NPC1L1 on the cell surface has been developed. It is noteworthy that whereas two cell lines (CaCo-2 and HepG2) commonly used for studying NPC1L1-dependent processes express almost undetectable levels of NPC1L1 at the cell surface, polarized Madin-Darby canine kidney (MDCKII) cells endogenously express 4 x 10(5) [(3)H]AS sites/cell under basal conditions. Depleting endogenous cholesterol with the HMG CoA reductase inhibitor lovastatin leads to a 2-fold increase in the surface expression of NPC1L1, supporting the contention that MDCKII cells respond to changes in cholesterol homeostasis by up-regulating a pathway for cholesterol influx. However, a significant increase in surface expression levels of NPC1L1 is necessary to characterize a pharmacologically sensitive, EZE-dependent pathway of cholesterol uptake in these cells. Remarkably, the affinity of EZE analogs for binding to NPC1L1 is almost identical to the IC(50) blocking cholesterol flux through NPC1L1 in MDCKII cells. From a mechanistic standpoint, these observations support the contention that EZE analogs and cholesterol share the same/overlapping binding site(s) or are tightly coupled through allosteric interactions.
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Affiliation(s)
- Adam B Weinglass
- Department of Ion Channels, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA.
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21
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Liu CJ, Priest BT, Bugianesi RM, Dulski PM, Felix JP, Dick IE, Brochu RM, Knaus HG, Middleton RE, Kaczorowski GJ, Slaughter RS, Garcia ML, Köhler MG. A high-capacity membrane potential FRET-based assay for NaV1.8 channels. Assay Drug Dev Technol 2006; 4:37-48. [PMID: 16506887 DOI: 10.1089/adt.2006.4.37] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Clinical treatment of neuropathic pain can be achieved with a number of different drugs, some of which interact with all members of the voltage-gated sodium channel (NaV1) family. However, block of central nervous system and cardiac NaV1 channels can cause dose-limiting side effects, preventing many patients from achieving adequate pain relief. Expression of the tetrodotoxin-resistant NaV1.8 subtype is restricted to small-diameter sensory neurons, and several lines of evidence indicate a role for NaV1.8 in pain processing. Given these features, NaV1.8 subtype-selective blockers are predicted to be efficacious in the treatment of neuropathic pain and to be associated with fewer adverse effects than currently available therapies. To facilitate the identification of NaV1.8-specific inhibitors, we stably expressed the human NaV1.8 channel together with the auxiliary human beta1 subunit (NaV beta1) in human embryonic kidney 293 cells. Heterologously expressed human NaV1.8/NaV beta1 channels display biophysical properties that are similar to those of tetrodotoxin-resistant channels present in mouse dorsal root ganglion neurons. A membrane potential, fluorescence resonance energy transfer-based functional assay on a fluorometric imaging plate reader (FLIPR-Tetra, Molecular Devices, Sunnyvale, CA) platform has been established. This highcapacity assay is sensitive to known state-dependent NaV1 modulators and can be used to identify novel and selective NaV1.8 inhibitors.
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Affiliation(s)
- Chou J Liu
- Department of Ion Channels, Merck Research Laboratories, Rahway, NJ 07065, USA
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22
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Ok D, Li C, Abbadie C, Felix JP, Fisher MH, Garcia ML, Kaczorowski GJ, Lyons KA, Martin WJ, Priest BT, Smith MM, Williams BS, Wyvratt MJ, Parsons WH. Synthesis and SAR of 1,2-trans-(1-hydroxy-3-phenylprop-1-yl)cyclopentane carboxamide derivatives, a new class of sodium channel blockers. Bioorg Med Chem Lett 2006; 16:1358-61. [PMID: 16337121 DOI: 10.1016/j.bmcl.2005.11.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Revised: 11/13/2005] [Accepted: 11/14/2005] [Indexed: 11/17/2022]
Abstract
Novel cyclopentane-based 3-phenyl-1-hydroxypropyl compounds were evaluated for inhibitory activity against the peripheral nerve sodium channel Na(V)1.7 and off-target activity against the cardiac potassium channel hERG. The stereochemistry of the hydroxyl group and substitution on the phenyl rings with either fluorinated O-alkyl or alkyl groups were found to be critical for conferring potency against Na(V)1.7. A benchmark compound from this series displayed efficacy in rat models of inflammatory and neuropathic pain.
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Affiliation(s)
- Dong Ok
- Department of Medicinal Chemistry, Merck Research Laboratories, Rahway, NJ 07065, USA.
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23
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Bugianesi RM, Augustine PR, Azer K, Dufresne C, Herrington J, Kath GS, McManus OB, Napolitano CS, Rush A, Sachs J, Simpson N, Wismer MK, Kaczorowski GJ, Slaughter RS. A Cell-Sparing Electric Field Stimulation Technique for High-Throughput Screening of Voltage-Gated Ion Channels. Assay Drug Dev Technol 2006; 4:21-35. [PMID: 16506886 DOI: 10.1089/adt.2006.4.21] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Trans Cell Layer Electrical Field Stimulation (TCL-EFS) system has been developed for high-throughput screening (HTS) of voltage-gated ion channels in microplate format on a Voltage-Ion Probe Reader (VIPR) platform. In this design, a wire electrode is placed above the cell layer of each filter well, and a whole plate perimeter electrode resides beneath the filter layer. This configuration allows the electrodes to be placed away from the cell layer to minimize the near electrode field effects on cell function and dye bleaching observed with other existing designs. Mathematical simulation indicates that the electric field at the cell layer becomes uniform as the top electrode is raised to a position near the surface of the solution in the well. Using the TCL-EFS system and membrane potential fluorescence resonance energy transfer (FRET) dyes, the sensitivity of voltage-gated sodium channels to tetrodotoxin and other channel inhibitors was found to be similar to those determined by established electrophysiological and more conventional VIPR techniques. A good correlation was also observed with the TCL-EFS system for inhibition of Cav2.2 by omega-conotoxin-GVIA and for block of Cav1.2 by known small molecule inhibitors. Thus, the TCLEFS system is suitable for both quantitative analysis and HTS of voltage-gated sodium and calcium channels, without the liabilities of previously reported EFS methodologies.
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Affiliation(s)
- Randal M Bugianesi
- Department of Ion Channels, Merck Research Laboratories, Rahway, NJ 07065, USA.
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24
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Novel Sodium Channel Blockers for the Treatment of Neuropathic Pain. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2006. [DOI: 10.1016/s0065-7743(06)41004-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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25
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Brochu RM, Dick IE, Tarpley JW, McGowan E, Gunner D, Herrington J, Shao PP, Ok D, Li C, Parsons WH, Stump GL, Regan CP, Lynch JJ, Lyons KA, McManus OB, Clark S, Ali Z, Kaczorowski GJ, Martin WJ, Priest BT. Block of peripheral nerve sodium channels selectively inhibits features of neuropathic pain in rats. Mol Pharmacol 2005; 69:823-32. [PMID: 16301337 DOI: 10.1124/mol.105.018127] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Several sodium channel blockers are used clinically to treat neuropathic pain. However, many patients fail to achieve adequate pain relief from these highly brain-penetrant drugs because of dose-limiting central nervous system side effects. Here, we describe the functional properties of trans-N-{[2'-(aminosulfonyl)biphenyl-4-yl]methyl}-N-methyl-N'-[4-(trifluoromethoxy)benzyl]cyclopentane-1,2-dicarboxamide (CDA54), a peripherally acting sodium channel blocker. In whole-cell electrophysiological assays, CDA54 blocked the inactivated states of hNa(V)1.7 and hNa(V)1.8, two channels of the peripheral nervous system implicated in nociceptive transmission, with affinities of 0.25 and 0.18 microM, respectively. CDA54 displayed similar affinities for the tetrodotoxin-resistant Na+ current in small-diameter mouse dorsal root ganglion neurons. Peripheral nerve injury causes spontaneous electrical activity in normally silent sensory neurons. CDA54 inhibited these injury-induced spontaneous action potentials at concentrations 10-fold lower than those required to block normal A- and C-fiber conduction. Consistent with the selective inhibition of injury-induced firing, CDA54 (10 mg/kg p.o.) significantly reduced behavioral signs of neuropathic pain in two nerve injury models, whereas the same dose of CDA54 did not affect acute nociception or motor coordination. In anesthetized dogs, CDA54, at plasma concentrations of 6.7 microM, had no effect on cardiac electrophysiological parameters including conduction. Thus, the peripheral nerve sodium channel blocker CDA54 selectively inhibits sensory nerve signaling associated with neuropathic pain.
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Affiliation(s)
- Richard M Brochu
- Department of Ion Channels, Merck Research Laboratories, Rahway, NJ, USA
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26
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Shao PP, Ok D, Fisher MH, Garcia ML, Kaczorowski GJ, Li C, Lyons KA, Martin WJ, Meinke PT, Priest BT, Smith MM, Wyvratt MJ, Ye F, Parsons WH. Novel cyclopentane dicarboxamide sodium channel blockers as a potential treatment for chronic pain. Bioorg Med Chem Lett 2005; 15:1901-7. [PMID: 15780630 DOI: 10.1016/j.bmcl.2005.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 01/31/2005] [Accepted: 02/01/2005] [Indexed: 11/20/2022]
Abstract
A series of new voltage-gated sodium channel blockers were prepared based on the screening lead succinic diamide BPBTS. Replacement of the succinimide linker with the more rigid cyclic 1,2-trans-diamide linker was well tolerated. N-Methylation on the biphenylsulfonamide side of the amide moiety significantly reduced the clearance rate in rat pharmacokinetic studies.
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Affiliation(s)
- Pengchang P Shao
- Department of Medicinal Chemistry, Merck Research Laboratories, Rahway, NJ 07065, USA
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27
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Liang J, Brochu RM, Cohen CJ, Dick IE, Felix JP, Fisher MH, Garcia ML, Kaczorowski GJ, Lyons KA, Meinke PT, Priest BT, Schmalhofer WA, Smith MM, Tarpley JW, Williams BS, Martin WJ, Parsons WH. Discovery of potent and use-dependent sodium channel blockers for treatment of chronic pain. Bioorg Med Chem Lett 2005; 15:2943-7. [PMID: 15878274 DOI: 10.1016/j.bmcl.2005.02.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 02/18/2005] [Accepted: 02/22/2005] [Indexed: 11/18/2022]
Abstract
A new series of voltage-gated sodium channel blockers with potential for treatment of chronic pain is reported. Systematic structure-activity relationship studies, starting with compound 1, led to identification of potent analogs that displayed use-dependent block of sodium channels, were efficacious in pain models in vivo, and most importantly, were devoid of activity against the cardiac potassium channel hERG.
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Affiliation(s)
- Jun Liang
- Department of Medicinal Chemistry, Merck Research Laboratories, Rahway, NJ 07065, USA.
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