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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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Li T, Xi C, Yu Y, Wang N, Wang X, Iwasaki A, Fang F, Ding L, Li S, Zhang W, Yuan Y, Wang T, Yan X, He S, Cao Z, Naman CB. Targeted Discovery of Amantamide B, an Ion Channel Modulating Nonapeptide from a South China Sea Oscillatoria Cyanobacterium. JOURNAL OF NATURAL PRODUCTS 2022; 85:493-500. [PMID: 34986303 DOI: 10.1021/acs.jnatprod.1c00983] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Amantamide B (1) is a new linear nonapeptide analogue of the cyanobacterial natural product amantamide A (2), and both have methyl ester and butanamide termini. These compounds were discovered in this study from the organic extract of a tropical marine filamentous cyanobacterium, Oscillatoria sp., collected around the Paracel Islands in the South China Sea. The use of LC-MS/MS molecular networking for sample prioritization and as an analytical dereplication tool facilitated the targeted isolation of 1 and 2. These molecules were characterized by spectroscopy and spectrometry, and configurational assignments were determined using chemical degradation and chiral-phase HPLC analysis. Compounds 1 and 2 modulated spontaneous calcium oscillations without notable cytotoxicity at 10 μM in short duration in vitro testing on primary cultured neocortical neurons, a model system that evaluates neuronal excitability and/or the potential activity on Ca2+ signaling. Both molecules were also found to be moderately cytotoxic in longer duration bioassays, with in vitro IC50 values of 1-10 μM against CCRF-CEM human T lymphoblastoid cells and U937 human histiocytic lymphoma cells. These formerly undiscovered bioactivities of known compound 2 expand upon its previously reported function as a selective CXCR7 agonist among 168 GPCR targets.
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Affiliation(s)
- Te Li
- School of Marine Science, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Chuchu Xi
- State Key Laboratory of Natural Medicines & Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, People's Republic of China
| | - Yiyi Yu
- State Key Laboratory of Natural Medicines & Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, People's Republic of China
| | - Ning Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, People's Republic of China
| | - Xiao Wang
- Department of Pathology and Pathogen Biology, College of Medicine, Ningbo University, Ningbo, Zhejiang 315211, People's Republic of China
| | - Arihiro Iwasaki
- Department of Chemistry, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Fang Fang
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Lijian Ding
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Shuang Li
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Weiyan Zhang
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Ye Yuan
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Tingting Wang
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Xiaojun Yan
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Shan He
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
| | - Zhengyu Cao
- State Key Laboratory of Natural Medicines & Jiangsu Provincial Key Laboratory for TCM Evaluation and Translational Development, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu 211198, People's Republic of China
| | - C Benjamin Naman
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Department of Marine Pharmacy, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315800, People's Republic of China
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Activation of voltage-gated sodium channels by BmK NT1 augments NMDA receptor function through Src family kinase signaling pathway in primary cerebellar granule cell cultures. Neuropharmacology 2020; 180:108291. [PMID: 32931812 DOI: 10.1016/j.neuropharm.2020.108291] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 08/23/2020] [Accepted: 08/26/2020] [Indexed: 12/29/2022]
Abstract
Voltage-gated sodium channels (VGSCs) are responsible for the generation and propagation of action potentials in excitable cells and are the molecular targets of an array of neurotoxins. BmK NT1, an α-scorpion toxin obtained from the scorpion Buthus martensii Karsch (BmK), produces neurotoxicity that is associated with extracellular Ca2+ influx through Na+-Ca2+ exchangers, N-methyl-d-aspartic acid (NMDA) receptors, and L-type Ca2+ channels in cultured cerebellar granule cells (CGCs). In the present study, we demonstrated that BmK NT1 triggered concentration-dependent release of excitatory neurotransmitters, glutamate and aspartate; both effects were eliminated by VGSC blocker, tetrodotoxin. More importantly, we demonstrated that a threshold concentration of BmK NT1 that produced marginal Ca2+ influx and neuronal death augmented glutamate-induced Ca2+ elevation and neuronal death in CGCs. BmK NT1-augmented glutamate-induced Ca2+ influx and neuronal death were suppressed by tetrodotoxin and MK-801 suggesting that the augmentation was through activation of VGSCs and NMDA receptors. Consistently, BmK NT1 also enhanced NMDA-induced Ca2+ influx. Further mechanistic investigations demonstrated that BmK NT1 increased the expression level of NMDA receptors on the plasma membrane and increased the phosphorylation level of NR2B at Tyr1472. Src family kinase inhibitor, 1-tert-butyl-3-(4-chlorophenyl)pyrazolo[3,4-d]pyrimidin-4-yl]amine (PP2), but not the inactive analogue, 4-amino-1-phenylpyrazolo[3,4-d]pyrimidine (PP3), eliminated BmK NT1-triggered NR2B phosphorylation, NMDA receptor trafficking, as well as BmK NT1-augmented NMDA Ca2+ response and neuronal death. Considered together, these data demonstrated that both presynaptic (excitatory amino acid release) and postsynaptic mechanisms (augmentation of NMDA receptor function) are critical for VGSC activation-induced neurotoxicity in primary CGC cultures.
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Painful and painless mutations of SCN9A and SCN11A voltage-gated sodium channels. Pflugers Arch 2020; 472:865-880. [PMID: 32601768 PMCID: PMC7351857 DOI: 10.1007/s00424-020-02419-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/25/2020] [Accepted: 06/10/2020] [Indexed: 12/11/2022]
Abstract
Chronic pain is a global problem affecting up to 20% of the world’s population and has a significant economic, social and personal cost to society. Sensory neurons of the dorsal root ganglia (DRG) detect noxious stimuli and transmit this sensory information to regions of the central nervous system (CNS) where activity is perceived as pain. DRG neurons express multiple voltage-gated sodium channels that underlie their excitability. Research over the last 20 years has provided valuable insights into the critical roles that two channels, NaV1.7 and NaV1.9, play in pain signalling in man. Gain of function mutations in NaV1.7 cause painful conditions while loss of function mutations cause complete insensitivity to pain. Only gain of function mutations have been reported for NaV1.9. However, while most NaV1.9 mutations lead to painful conditions, a few are reported to cause insensitivity to pain. The critical roles these channels play in pain along with their low expression in the CNS and heart muscle suggest they are valid targets for novel analgesic drugs.
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High-Throughput Fluorescence Assays for Ion Channels and GPCRs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:27-72. [DOI: 10.1007/978-3-030-12457-1_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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6
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Sirenko O, Parham F, Dea S, Sodhi N, Biesmans S, Mora-Castilla S, Ryan K, Behl M, Chandy G, Crittenden C, Vargas-Hurlston S, Guicherit O, Gordon R, Zanella F, Carromeu C. Functional and Mechanistic Neurotoxicity Profiling Using Human iPSC-Derived Neural 3D Cultures. Toxicol Sci 2019; 167:58-76. [PMID: 30169818 DOI: 10.1093/toxsci/kfy218] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Neurological disorders affect millions of people worldwide and appear to be on the rise. Whereas the reason for this increase remains unknown, environmental factors are a suspected contributor. Hence, there is an urgent need to develop more complex, biologically relevant, and predictive in vitro assays to screen larger sets of compounds with the potential for neurotoxicity. Here, we employed a human induced pluripotent stem cell (iPSC)-based 3D neural platform composed of mature cortical neurons and astrocytes as a model for this purpose. The iPSC-derived human 3D cortical neuron/astrocyte co-cultures (3D neural cultures) present spontaneous synchronized, readily detectable calcium oscillations. This advanced neural platform was optimized for high-throughput screening in 384-well plates and displays highly consistent, functional performance across different wells and plates. Characterization of oscillation profiles in 3D neural cultures was performed through multi-parametric analysis that included the calcium oscillation rate and peak width, amplitude, and waveform irregularities. Cellular and mitochondrial toxicity were assessed by high-content imaging. For assay characterization, we used a set of neuromodulators with known mechanisms of action. We then explored the neurotoxic profile of a library of 87 compounds that included pharmaceutical drugs, pesticides, flame retardants, and other chemicals. Our results demonstrated that 57% of the tested compounds exhibited effects in the assay. The compounds were then ranked according to their effective concentrations based on in vitro activity. Our results show that a human iPSC-derived 3D neural culture assay platform is a promising biologically relevant tool to assess the neurotoxic potential of drugs and environmental toxicants.
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Affiliation(s)
| | - Frederick Parham
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Steven Dea
- StemoniX, Inc, Maple Grove, Minnesota 55311
| | - Neha Sodhi
- StemoniX, Inc, Maple Grove, Minnesota 55311
| | | | | | - Kristen Ryan
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Mamta Behl
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
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Zhao F, Tang Q, Xu J, Wang S, Li S, Zou X, Cao Z. Dehydrocrenatidine Inhibits Voltage-Gated Sodium Channels and Ameliorates Mechanic Allodia in a Rat Model of Neuropathic Pain. Toxins (Basel) 2019; 11:E229. [PMID: 31003411 PMCID: PMC6521113 DOI: 10.3390/toxins11040229] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 12/27/2022] Open
Abstract
Picrasma quassioides (D. Don) Benn, a medical plant, is used in clinic to treat inflammation, pain, sore throat, and eczema. The alkaloids are the main active components in P. quassioides. In this study, we examined the analgesic effect of dehydrocrenatidine (DHCT), a β-carboline alkaloid abundantly found in P. quassioides in a neuropathic pain rat model of a sciatic nerve chronic constriction injury. DHCT dose-dependently attenuated the mechanic allodynia. In acutely isolated dorsal root ganglion, DHCT completely suppressed the action potential firing. Further electrophysiological characterization demonstrated that DHCT suppressed both tetrodotoxin-resistant (TTX-R) and sensitive (TTX-S) voltage-gated sodium channel (VGSC) currents with IC50 values of 12.36 μM and 4.87 µM, respectively. DHCT shifted half-maximal voltage (V1/2) of inactivation to hyperpolarizing direction by ~16.7 mV in TTX-S VGSCs. In TTX-R VGSCs, DHCT shifted V1/2 of inactivation voltage to hyperpolarizing direction and V1/2 of activation voltage to more depolarizing potential by ~23.9 mV and ~12.2 mV, respectively. DHCT preferred to interact with an inactivated state of VGSCs and prolonged the repriming time in both TTX-S and TTX-R VGSCs, transiting the channels into a slow inactivated state from a fast inactivated state. Considered together, these data demonstrated that the analgesic effect of DHCT was likely though the inhibition of neuronal excitability.
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Affiliation(s)
- Fang Zhao
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Qinglian Tang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Jian Xu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Shuangyan Wang
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Shaoheng Li
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Xiaohan Zou
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
| | - Zhengyu Cao
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China.
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Black BJ, Atmaramani R, Plagens S, Campbell ZT, Dussor G, Price TJ, Pancrazio JJ. Emerging neurotechnology for antinoceptive mechanisms and therapeutics discovery. Biosens Bioelectron 2018; 126:679-689. [PMID: 30544081 DOI: 10.1016/j.bios.2018.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 11/01/2018] [Accepted: 11/10/2018] [Indexed: 12/20/2022]
Abstract
The tolerance, abuse, and potential exacerbation associated with classical chronic pain medications such as opioids creates a need for alternative therapeutics. Phenotypic screening provides a complementary approach to traditional target-based drug discovery. Profiling cellular phenotypes enables quantification of physiologically relevant traits central to a disease pathology without prior identification of a specific drug target. For complex disorders such as chronic pain, which likely involves many molecular targets, this approach may identify novel treatments. Sensory neurons, termed nociceptors, are derived from dorsal root ganglia (DRG) and can undergo changes in membrane excitability during chronic pain. In this review, we describe phenotypic screening paradigms that make use of nociceptor electrophysiology. The purpose of this paper is to review the bioelectrical behavior of DRG neurons, signaling complexity in sensory neurons, various sensory neuron models, assays for bioelectrical behavior, and emerging efforts to leverage microfabrication and microfluidics for assay development. We discuss limitations and advantages of these various approaches and offer perspectives on opportunities for future development.
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Affiliation(s)
- Bryan J Black
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA.
| | - Rahul Atmaramani
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Sarah Plagens
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Zachary T Campbell
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
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Zhang XY, Bi RY, Zhang P, Gan YH. Veratridine modifies the gating of human voltage-gated sodium channel Nav1.7. Acta Pharmacol Sin 2018; 39:1716-1724. [PMID: 29950616 DOI: 10.1038/s41401-018-0065-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 06/05/2018] [Indexed: 01/22/2023] Open
Abstract
Veratridine is a lipid-soluble neurotoxin derived from plants in the family Liliaceae. It has been broadly investigated for its action as a sodium channel agonist. However, the effects of veratridine on subtypes of sodium channels, especially Nav1.7, remain to be studied. Here, we investigated the effects of veratridine on human Nav1.7 ectopically expressed in HEK293A cells and recorded Nav1.7 currents from the cells using whole-cell patch clamp technique. We found that veratridine exerted a dose-dependent inhibitory effect on the peak current of Nav1.7, with the half-maximal inhibition concentration (IC50) of 18.39 µM. Meanwhile, veratridine also elicited tail current (linearly) and sustained current [half-maximal concentration (EC50): 9.53 µM], also in a dose-dependent manner. Veratridine (75 µM) shifted the half-maximal activation voltage of the Nav1.7 activation curve in the hyperpolarized direction, from -21.64 ± 0.75 mV to -28.14 ± 0.66 mV, and shifted the half-inactivation voltage of the steady-state inactivation curve from -59.39 ± 0.39 mV to -73.78 ± 0.5 mV. An increased frequency of stimulation decreased the peak and tail currents of Nav1.7 for each pulse along with pulse number, and increased the accumulated tail current at the end of train stimulation. These findings reveal the different modulatory effects of veratridine on the Nav1.7 peak current and tail current.
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Cardoso FC, Lewis RJ. Sodium channels and pain: from toxins to therapies. Br J Pharmacol 2018; 175:2138-2157. [PMID: 28749537 PMCID: PMC5980290 DOI: 10.1111/bph.13962] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/11/2017] [Accepted: 07/17/2017] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium channels (NaV channels) are essential for the initiation and propagation of action potentials that critically influence our ability to respond to a diverse range of stimuli. Physiological and pharmacological studies have linked abnormal function of NaV channels to many human disorders, including chronic neuropathic pain. These findings, along with the description of the functional properties and expression pattern of NaV channel subtypes, are helping to uncover subtype specific roles in acute and chronic pain and revealing potential opportunities to target these with selective inhibitors. High-throughput screens and automated electrophysiology platforms have identified natural toxins as a promising group of molecules for the development of target-specific analgesics. In this review, the role of toxins in defining the contribution of NaV channels in acute and chronic pain states and their potential to be used as analgesic therapies are discussed. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
- Fernanda C Cardoso
- Department of Chemistry and Structural Biology, Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLDAustralia
| | - Richard J Lewis
- Department of Chemistry and Structural Biology, Institute for Molecular BioscienceThe University of QueenslandBrisbaneQLDAustralia
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11
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Atkin TA, Maher CM, Gerlach AC, Gay BC, Antonio BM, Santos SC, Padilla KM, Rader J, Krafte DS, Fox MA, Stewart GR, Petrovski S, Devinsky O, Might M, Petrou S, Goldstein DB. A comprehensive approach to identifying repurposed drugs to treat SCN8A epilepsy. Epilepsia 2018; 59:802-813. [PMID: 29574705 DOI: 10.1111/epi.14037] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2018] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Many previous studies of drug repurposing have relied on literature review followed by evaluation of a limited number of candidate compounds. Here, we demonstrate the feasibility of a more comprehensive approach using high-throughput screening to identify inhibitors of a gain-of-function mutation in the SCN8A gene associated with severe pediatric epilepsy. METHODS We developed cellular models expressing wild-type or an R1872Q mutation in the Nav 1.6 sodium channel encoded by SCN8A. Voltage clamp experiments in HEK-293 cells expressing the SCN8A R1872Q mutation demonstrated a leftward shift in sodium channel activation as well as delayed inactivation; both changes are consistent with a gain-of-function mutation. We next developed a fluorescence-based, sodium flux assay and used it to assess an extensive library of approved drugs, including a panel of antiepileptic drugs, for inhibitory activity in the mutated cell line. Lead candidates were evaluated in follow-on studies to generate concentration-response curves for inhibiting sodium influx. Select compounds of clinical interest were evaluated by electrophysiology to further characterize drug effects on wild-type and mutant sodium channel functions. RESULTS The screen identified 90 drugs that significantly inhibited sodium influx in the R1872Q cell line. Four drugs of potential clinical interest-amitriptyline, carvedilol, nilvadipine, and carbamazepine-were further investigated and demonstrated concentration-dependent inhibition of sodium channel currents. SIGNIFICANCE A comprehensive drug repurposing screen identified potential new candidates for the treatment of epilepsy caused by the R1872Q mutation in the SCN8A gene.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Slavé Petrovski
- Pairnomix, Plymouth, MN, USA.,Florey Institute for Neuroscience and Mental Health and Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Orrin Devinsky
- Pairnomix, Plymouth, MN, USA.,Department of Neurology, New York University Medical Center, New York, NY, USA
| | - Matthew Might
- Pairnomix, Plymouth, MN, USA.,University of Alabama at Birmingham, Birmingham, AL, USA
| | - Steven Petrou
- Pairnomix, Plymouth, MN, USA.,Florey Institute for Neuroscience and Mental Health and Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - David B Goldstein
- Pairnomix, Plymouth, MN, USA.,Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, USA
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Wu Y, Ma H, Zhang F, Zhang C, Zou X, Cao Z. Selective Voltage-Gated Sodium Channel Peptide Toxins from Animal Venom: Pharmacological Probes and Analgesic Drug Development. ACS Chem Neurosci 2018; 9:187-197. [PMID: 29161016 DOI: 10.1021/acschemneuro.7b00406] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Navs) play critical roles in action potential generation and propagation. Nav channelopathy as well as pathological sensitization contribute to allodynia and hyperalgesia. Recent evidence has demonstrated the significant roles of Nav subtypes (Nav1.3, 1.7, 1.8, and 1.9) in nociceptive transduction, and therefore these Navs may represent attractive targets for analgesic drug discovery. Animal toxins are structurally diverse peptides that are highly potent yet selective on ion channel subtypes and therefore represent valuable probes to elucidate the structures, gating properties, and cellular functions of ion channels. In this review, we summarize recent advances on peptide toxins from animal venom that selectively target Nav1.3, 1.7, 1.8, and 1.9, along with their potential in analgesic drug discovery.
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Affiliation(s)
- Ying Wu
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Hui Ma
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Fan Zhang
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Chunlei Zhang
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Xiaohan Zou
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
| | - Zhengyu Cao
- Jiangsu Provincial Key Laboratory for TCM Evaluation
and Translational Development, China Pharmaceutical University, Nanjing 211198, China
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13
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Mechanism-specific assay design facilitates the discovery of Nav1.7-selective inhibitors. Proc Natl Acad Sci U S A 2018; 115:E792-E801. [PMID: 29311306 PMCID: PMC5789920 DOI: 10.1073/pnas.1713701115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Subtype-selective modulation of ion channels is often important, but extremely difficult to achieve for drug development. Using Nav1.7 as an example, we show that this challenge could be attributed to poor design in ion channel assays, which fail to detect most potent and selective compounds and are biased toward nonselective mechanisms. By exploiting different drug binding sites and modes of channel gating, we successfully direct a membrane potential assay toward non–pore-blocking mechanisms and identify Nav1.7-selective compounds. Our mechanistic approach to assay design addresses a significant hurdle in Nav1.7 drug discovery and is applicable to many other ion channels. Many ion channels, including Nav1.7, Cav1.3, and Kv1.3, are linked to human pathologies and are important therapeutic targets. To develop efficacious and safe drugs, subtype-selective modulation is essential, but has been extremely difficult to achieve. We postulate that this challenge is caused by the poor assay design, and investigate the Nav1.7 membrane potential assay, one of the most extensively employed screening assays in modern drug discovery. The assay uses veratridine to activate channels, and compounds are identified based on the inhibition of veratridine-evoked activities. We show that this assay is biased toward nonselective pore blockers and fails to detect the most potent, selective voltage-sensing domain 4 (VSD4) blockers, including PF-05089771 (PF-771) and GX-936. By eliminating a key binding site for pore blockers and replacing veratridine with a VSD-4 binding activator, we directed the assay toward non–pore-blocking mechanisms and discovered Nav1.7-selective chemical scaffolds. Hence, we address a major hurdle in Nav1.7 drug discovery, and this mechanistic approach to assay design is applicable to Cav3.1, Kv1.3, and many other ion channels to facilitate drug discovery.
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González-Cano R, Tejada MÁ, Artacho-Cordón A, Nieto FR, Entrena JM, Wood JN, Cendán CM. Effects of Tetrodotoxin in Mouse Models of Visceral Pain. Mar Drugs 2017; 15:E188. [PMID: 28635651 PMCID: PMC5484138 DOI: 10.3390/md15060188] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/07/2017] [Accepted: 06/16/2017] [Indexed: 12/11/2022] Open
Abstract
Visceral pain is very common and represents a major unmet clinical need for which current pharmacological treatments are often insufficient. Tetrodotoxin (TTX) is a potent neurotoxin that exerts analgesic actions in both humans and rodents under different somatic pain conditions, but its effect has been unexplored in visceral pain. Therefore, we tested the effects of systemic TTX in viscero-specific mouse models of chemical stimulation of the colon (intracolonic instillation of capsaicin and mustard oil) and intraperitoneal cyclophosphamide-induced cystitis. The subcutaneous administration of TTX dose-dependently inhibited the number of pain-related behaviors in all evaluated pain models and reversed the referred mechanical hyperalgesia (examined by stimulation of the abdomen with von Frey filaments) induced by capsaicin and cyclophosphamide, but not that induced by mustard oil. Morphine inhibited both pain responses and the referred mechanical hyperalgesia in all tests. Conditional nociceptor‑specific Nav1.7 knockout mice treated with TTX showed the same responses as littermate controls after the administration of the algogens. No motor incoordination after the administration of TTX was observed. These results suggest that blockade of TTX-sensitive sodium channels, but not Nav1.7 subtype alone, by systemic administration of TTX might be a potential therapeutic strategy for the treatment of visceral pain.
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Affiliation(s)
- Rafael González-Cano
- Department of Pharmacology, Biomedical Research Centre and Institute of Neuroscience, Faculty of Medicine, University of Granada, 18016 Granada, Spain.
- Biosanitary Research Institute, University Hospital Complex of Granada, 18012 Granada, Spain.
| | - Miguel Ángel Tejada
- Department of Pharmacology, Biomedical Research Centre and Institute of Neuroscience, Faculty of Medicine, University of Granada, 18016 Granada, Spain.
- Biosanitary Research Institute, University Hospital Complex of Granada, 18012 Granada, Spain.
| | - Antonia Artacho-Cordón
- Department of Pharmacology, Biomedical Research Centre and Institute of Neuroscience, Faculty of Medicine, University of Granada, 18016 Granada, Spain.
- Biosanitary Research Institute, University Hospital Complex of Granada, 18012 Granada, Spain.
| | - Francisco Rafael Nieto
- Department of Pharmacology, Biomedical Research Centre and Institute of Neuroscience, Faculty of Medicine, University of Granada, 18016 Granada, Spain.
- Biosanitary Research Institute, University Hospital Complex of Granada, 18012 Granada, Spain.
| | - José Manuel Entrena
- Animal Behavior Research Unit, Scientific Instrumentation Center, University of Granada, Armilla, 18100 Granada, Spain.
| | - John N Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK.
| | - Cruz Miguel Cendán
- Department of Pharmacology, Biomedical Research Centre and Institute of Neuroscience, Faculty of Medicine, University of Granada, 18016 Granada, Spain.
- Biosanitary Research Institute, University Hospital Complex of Granada, 18012 Granada, Spain.
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15
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Deuis JR, Mueller A, Israel MR, Vetter I. The pharmacology of voltage-gated sodium channel activators. Neuropharmacology 2017; 127:87-108. [PMID: 28416444 DOI: 10.1016/j.neuropharm.2017.04.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/28/2017] [Accepted: 04/10/2017] [Indexed: 12/19/2022]
Abstract
Toxins and venom components that target voltage-gated sodium (NaV) channels have evolved numerous times due to the importance of this class of ion channels in the normal physiological function of peripheral and central neurons as well as cardiac and skeletal muscle. NaV channel activators in particular have been isolated from the venom of spiders, wasps, snakes, scorpions, cone snails and sea anemone and are also produced by plants, bacteria and algae. These compounds have provided key insight into the molecular structure, function and pathophysiological roles of NaV channels and are important tools due to their at times exquisite subtype-selectivity. We review the pharmacology of NaV channel activators with particular emphasis on mammalian isoforms and discuss putative applications for these compounds. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Jennifer R Deuis
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Alexander Mueller
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Mathilde R Israel
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia
| | - Irina Vetter
- Centre for Pain Research, Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4072, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia.
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Phenytoin: a step by step insight into its multiple mechanisms of action-80 years of mechanistic studies in neuropharmacology. J Neurol 2017; 264:2043-2047. [PMID: 28349209 DOI: 10.1007/s00415-017-8465-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 12/15/2022]
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17
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Molokanova E, Mercola M, Savchenko A. Bringing new dimensions to drug discovery screening: impact of cellular stimulation technologies. Drug Discov Today 2017; 22:1045-1055. [PMID: 28179145 DOI: 10.1016/j.drudis.2017.01.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/09/2016] [Accepted: 01/27/2017] [Indexed: 01/08/2023]
Abstract
The current mandate for the drug discovery industry is to develop more efficient drugs faster while reducing the costs associated with their development. Incorporation of cell stimulation technologies during screening assays is expected to revolutionize the discovery of novel drugs as well as safety pharmacology. In this review, we highlight 'classical' and emerging cell stimulation technologies that provide the ability to evaluate the effects of drug candidates on cells in different functional states to assess clinically relevant phenotypes.
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Affiliation(s)
- Elena Molokanova
- Nanotools Bioscience, Encinitas, CA 92024, USA; Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Mark Mercola
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA; Department of Medicine and Cardiovascular Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Alex Savchenko
- Department of Medicine and Cardiovascular Institute, Stanford University, Palo Alto, CA 94304, USA; Department of Pediatrics, University of California-San Diego, La Jolla, CA 92093, USA.
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