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Joseph DJ, Von Deimling M, Risbud R, McCoy AJ, Marsh ED. Loss of postnatal Arx transcriptional activity in parvalbumin interneurons reveals non-cell autonomous disturbances in CA1 pyramidal cells. Neuroscience 2024; 558:128-150. [PMID: 38788829 PMCID: PMC11381180 DOI: 10.1016/j.neuroscience.2024.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 04/16/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024]
Abstract
Maintenance of proper electrophysiological and connectivity profiles in the adult brain may be a perturbation point in neurodevelopmental disorders (NDDs). How these profiles are maintained within mature circuits is unclear. We recently demonstrated that postnatal ablation of the Aristaless (Arx) homeobox gene in parvalbumin interneurons (PVIs) alone led to dysregulation of their transcriptome and alterations in their functional as well as network properties in the hippocampal cornu Ammoni first region (CA1). Here, we characterized CA1 pyramidal cells (PCs) responses in this conditional knockout (CKO) mouse to further understand the circuit mechanisms by which postnatal Arx expression regulates mature CA1 circuits. Field recordings of network excitability showed that CA1 PC ensembles were less excitable in response to unpaired stimulations but exhibited enhanced excitability in response to paired-pulse stimulations. Whole-cell voltage clamp recordings revealed a significant increase in the frequency of spontaneous inhibitory postsynaptic currents onto PCs. In contrast, excitatory drive from evoked synaptic transmission was reduced while that of inhibitory synaptic transmission was increased. Current clamp recordings showed increase excitability in several sub- and threshold membrane properties that correlated with an increase in voltage-gated Na+ current. Our data suggest that, in addition to cell-autonomous disruption in PVIs, loss of Arx postnatal transcriptional activity in PVIs led to complex dysfunctions in PCs in CA1 microcircuits. These non-cell autonomous effects are likely the product of breakdown in feedback and/or feedforward processes and should be considered as fundamental contributors to the circuit mechanisms of NDDs such as Arx-linked early-onset epileptic encephalopathies.
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Affiliation(s)
- Donald J Joseph
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Markus Von Deimling
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Urology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rashmi Risbud
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Almedia J McCoy
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eric D Marsh
- Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Departments of Neurology and Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Nascimento de Lima AP, Zhang H, Chen L, Effraim PR, Gomis-Perez C, Cheng X, Huang J, Waxman SG, Dib-Hajj SD. Nav1.8 in small dorsal root ganglion neurons contributes to vincristine-induced mechanical allodynia. Brain 2024; 147:3157-3170. [PMID: 38447953 DOI: 10.1093/brain/awae071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/29/2024] [Accepted: 02/15/2024] [Indexed: 03/08/2024] Open
Abstract
Vincristine-induced peripheral neuropathy is a common side effect of vincristine treatment, which is accompanied by pain and can be dose-limiting. The molecular mechanisms that underlie vincristine-induced pain are not well understood. We have established an animal model to investigate pathophysiological mechanisms of vincristine-induced pain. Our previous studies have shown that the tetrodotoxin-sensitive voltage-gated sodium channel Nav1.6 in medium-diameter dorsal root ganglion (DRG) neurons contributes to the maintenance of vincristine-induced allodynia. In this study, we investigated the effects of vincristine administration on excitability in small-diameter DRG neurons and whether the tetrodotoxin-resistant (TTX-R) Nav1.8 channels contribute to mechanical allodynia. Current-clamp recordings demonstrated that small DRG neurons become hyper-excitable following vincristine treatment, with both reduced current threshold and increased firing frequency. Using voltage-clamp recordings in small DRG neurons, we now show an increase in TTX-R current density and a -7.3 mV hyperpolarizing shift in the half-maximal potential (V1/2) of activation of Nav1.8 channels in vincristine-treated animals, which likely contributes to the hyperexcitability that we observed in these neurons. Notably, vincristine treatment did not enhance excitability of small DRG neurons from Nav1.8 knockout mice, and the development of mechanical allodynia was delayed but not abrogated in these mice. Together, our data suggest that sodium channel Nav1.8 in small DRG neurons contributes to the development of vincristine-induced mechanical allodynia.
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Affiliation(s)
- Ana Paula Nascimento de Lima
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Huiran Zhang
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Lubin Chen
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Philip R Effraim
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Carolina Gomis-Perez
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Xiaoyang Cheng
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Jianying Huang
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Sulayman D Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA
- Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
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3
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Zhou R, Fu W, Vasylyev D, Waxman SG, Liu CJ. Ion channels in osteoarthritis: emerging roles and potential targets. Nat Rev Rheumatol 2024; 20:545-564. [PMID: 39122910 DOI: 10.1038/s41584-024-01146-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2024] [Indexed: 08/12/2024]
Abstract
Osteoarthritis (OA) is a highly prevalent joint disease that causes substantial disability, yet effective approaches to disease prevention or to the delay of OA progression are lacking. Emerging evidence has pinpointed ion channels as pivotal mediators in OA pathogenesis and as promising targets for disease-modifying treatments. Preclinical studies have assessed the potential of a variety of ion channel modulators to modify disease pathways involved in cartilage degeneration, synovial inflammation, bone hyperplasia and pain, and to provide symptomatic relief in models of OA. Some of these modulators are currently being evaluated in clinical trials. This review explores the structures and functions of ion channels, including transient receptor potential channels, Piezo channels, voltage-gated sodium channels, voltage-dependent calcium channels, potassium channels, acid-sensing ion channels, chloride channels and the ATP-dependent P2XR channels in the osteoarthritic joint. The discussion spans channel-targeting drug discovery and potential clinical applications, emphasizing opportunities for further research, and underscoring the growing clinical impact of ion channel biology in OA.
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Affiliation(s)
- Renpeng Zhou
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA
| | - Wenyu Fu
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA
| | - Dmytro Vasylyev
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Chuan-Ju Liu
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA.
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4
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Neumann B, McCarthy S, Gonen S. Structural basis of inhibition of human Na V1.8 by the tarantula venom peptide Protoxin-I. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609828. [PMID: 39253517 PMCID: PMC11383277 DOI: 10.1101/2024.08.27.609828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
Voltage-gated sodium channels (NaVs) selectively permit diffusion of sodium ions across the cell membrane and, in excitable cells, are responsible for propagating action potentials. One of the nine human NaV isoforms, NaV1.8, is a promising target for analgesics, and selective inhibitors are of interest as therapeutics. One such inhibitor, the gating-modifier peptide Protoxin-I derived from tarantula venom, blocks channel opening by shifting the activation voltage threshold to more depolarised potentials, but the structural basis for this inhibition has not previously been determined. Using monolayer graphene grids, we report the cryogenic electron microscopy structures of full-length human apo-NaV1.8 and the Protoxin-I-bound complex at 3.1 Å and 2.8 Å resolution, respectively. The apo structure shows an unexpected movement of the Domain I S4-S5 helix, and VSDI was unresolvable. We find that Protoxin-I binds to and displaces the VSDII S3-S4 linker, hindering translocation of the S4II helix during activation.
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Affiliation(s)
- Bryan Neumann
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA 92617, USA
| | - Stephen McCarthy
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA 92617, USA
| | - Shane Gonen
- Department of Molecular Biology and Biochemistry, University of California Irvine, CA 92617, USA
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5
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Kantarci H, Elvira PD, Thottumkara AP, O'Connell EM, Iyer M, Donovan LJ, Dugan MQ, Ambiel N, Granados A, Zeng H, Saw NL, Brosius Lutz A, Sloan SA, Gray EE, Tran KV, Vichare A, Yeh AK, Münch AE, Huber M, Agrawal A, Morri M, Zhong H, Shamloo M, Anderson TA, Tawfik VL, Du Bois J, Zuchero JB. Schwann cell-secreted PGE 2 promotes sensory neuron excitability during development. Cell 2024; 187:4690-4712.e30. [PMID: 39142281 DOI: 10.1016/j.cell.2024.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/18/2024] [Accepted: 06/21/2024] [Indexed: 08/16/2024]
Abstract
Electrical excitability-the ability to fire and propagate action potentials-is a signature feature of neurons. How neurons become excitable during development and whether excitability is an intrinsic property of neurons remain unclear. Here, we demonstrate that Schwann cells, the most abundant glia in the peripheral nervous system, promote somatosensory neuron excitability during development. We find that Schwann cells secrete prostaglandin E2, which is necessary and sufficient to induce developing somatosensory neurons to express normal levels of genes required for neuronal function, including voltage-gated sodium channels, and to fire action potential trains. Inactivating this signaling pathway in Schwann cells impairs somatosensory neuron maturation, causing multimodal sensory defects that persist into adulthood. Collectively, our studies uncover a neurodevelopmental role for prostaglandin E2 distinct from its established role in inflammation, revealing a cell non-autonomous mechanism by which glia regulate neuronal excitability to enable the development of normal sensory functions.
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Affiliation(s)
- Husniye Kantarci
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Pablo D Elvira
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | | | - Emma M O'Connell
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Manasi Iyer
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lauren J Donovan
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Micaela Quinn Dugan
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nicholas Ambiel
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Hong Zeng
- Transgenic, Knockout and Tumor model Center (TKTC), Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nay L Saw
- Behavioral and Functional Neuroscience Laboratory, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amanda Brosius Lutz
- Department of Obstetrics and Gynecology, University Hospital, Bern, Switzerland
| | - Steven A Sloan
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Erin E Gray
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Khanh V Tran
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aditi Vichare
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ashley K Yeh
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alexandra E Münch
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Max Huber
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Aditi Agrawal
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | | | - Haining Zhong
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Mehrdad Shamloo
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Behavioral and Functional Neuroscience Laboratory, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas Anthony Anderson
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Vivianne L Tawfik
- Department of Anesthesiology, Perioperative & Pain Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - J Du Bois
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
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6
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Chuinsiri N, Siraboriphantakul N, Kendall L, Yarova P, Nile CJ, Song B, Obara I, Durham J, Telezhkin V. Calcium-sensing receptor regulates Kv7 channels via G i/o protein signalling and modulates excitability of human induced pluripotent stem cell-derived nociceptive-like neurons. Br J Pharmacol 2024; 181:2676-2696. [PMID: 38627101 DOI: 10.1111/bph.16349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/29/2024] [Accepted: 02/15/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND AND PURPOSE Neuropathic pain, a debilitating condition with unmet medical needs, can be characterised as hyperexcitability of nociceptive neurons caused by dysfunction of ion channels. Voltage-gated potassium channels type 7 (Kv7), responsible for maintaining neuronal resting membrane potential and thus excitability, reside under tight control of G protein-coupled receptors (GPCRs). Calcium-sensing receptor (CaSR) is a GPCR that regulates the activity of numerous ion channels, but whether CaSR can control Kv7 channel function has been unexplored until now. EXPERIMENTAL APPROACH Experiments were conducted in recombinant cell models, mouse dorsal root ganglia (DRG) neurons and human induced pluripotent stem cell (hiPSC)-derived nociceptive-like neurons using patch-clamp electrophysiology and molecular biology techniques. KEY RESULTS Our results demonstrate that CaSR is expressed in recombinant cell models, hiPSC-derived nociceptive-like neurons and mouse DRG neurons, and its activation induced depolarisation via Kv7.2/7.3 channel inhibition. The CaSR-Kv7.2/7.3 channel crosslink was mediated via the Gi/o protein-adenylate cyclase-cyclicAMP-protein kinase A signalling cascade. Suppression of CaSR function demonstrated a potential to rescue hiPSC-derived nociceptive-like neurons from algogenic cocktail-induced hyperexcitability. CONCLUSION AND IMPLICATIONS This study demonstrates that the CaSR-Kv7.2/7.3 channel crosslink, via a Gi/o protein signalling pathway, effectively regulates neuronal excitability, providing a feasible pharmacological target for neuronal hyperexcitability management in neuropathic pain.
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Affiliation(s)
- Nontawat Chuinsiri
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Institute of Dentistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand
- Oral Health Center, Suranaree University of TechnologyHospital, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | | | - Luke Kendall
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Polina Yarova
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Christopher J Nile
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Bing Song
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | - Ilona Obara
- School of Pharmacy, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Justin Durham
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Vsevolod Telezhkin
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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7
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Kimourtzis G, Rangwani N, Jenkins BJ, Jani S, McNaughton PA, Raouf R. Prostaglandin E2 depolarises sensory axons in vitro in an ANO1 and Nav1.8 dependent manner. Sci Rep 2024; 14:17360. [PMID: 39075089 PMCID: PMC11286870 DOI: 10.1038/s41598-024-67793-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 07/16/2024] [Indexed: 07/31/2024] Open
Abstract
Prostaglandin E2 (PGE2) is a major contributor to inflammatory pain hyperalgesia, however, the extent to which it modulates the activity of nociceptive axons is incompletely understood. We developed and characterized a microfluidic cell culture model to investigate sensitisation of the axons of dorsal root ganglia neurons. We show that application of PGE2 to fluidically isolated axons leads to sensitisation of their responses to depolarising stimuli. Interestingly the application of PGE2 to the DRG axons elicited a direct and persistent spiking activity propagated to the soma. Both the persistent activity and the membrane depolarisation in the axons are abolished by the EP4 receptor inhibitor and a blocker of cAMP synthesis. Further investigated into the mechanisms of the spiking activity showed that the PGE2 evoked depolarisation was inhibited by Nav1.8 sodium channel blockers but was refractory to the application of TTX or zatebradine. Interestingly, the depolarisation of axons was blocked by blocking ANO1 channels with T16Ainh-A01. We further show that PGE2-elicited axonal responses are altered by the changes in chloride gradient within the axons following treatment with bumetanide a Na-K-2Cl cotransporter NKCC1 inhibitor, but not by VU01240551 an inhibitor of potassium-chloride transporter KCC2. Our data demonstrate a novel role for PGE2/EP4/cAMP pathway which culminates in a sustained depolarisation of sensory axons mediated by a chloride current through ANO1 channels. Therefore, using a microfluidic culture model, we provide evidence for a potential dual function of PGE2 in inflammatory pain: it sensitises depolarisation-evoked responses in nociceptive axons and directly triggers action potentials by activating ANO1 and Nav1.8 channels.
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Affiliation(s)
- Georgios Kimourtzis
- Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE1 1UL, UK
| | - Natasha Rangwani
- Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE1 1UL, UK
| | - Bethan J Jenkins
- Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE1 1UL, UK
| | - Siddharth Jani
- Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE1 1UL, UK
| | - Peter A McNaughton
- Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE1 1UL, UK
| | - Ramin Raouf
- Wolfson Sensory, Pain and Regeneration Centre (SPaRC), Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, SE1 1UL, UK.
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8
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Zhang S, Chen L, Ladez SR, Seferge A, Liu J, Feng B. Blocking Aδ- and C-fiber neural transmission by sub-kilohertz peripheral nerve stimulation. Front Neurosci 2024; 18:1404903. [PMID: 39077428 PMCID: PMC11284050 DOI: 10.3389/fnins.2024.1404903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 07/02/2024] [Indexed: 07/31/2024] Open
Abstract
Introduction We recently showed that sub-kilohertz electrical stimulation of the afferent somata in the dorsal root ganglia (DRG) reversibly blocks afferent transmission. Here, we further investigated whether similar conduction block can be achieved by stimulating the nerve trunk with electrical peripheral nerve stimulation (ePNS). Methods We explored the mechanisms and parameters of conduction block by ePNS via ex vivo single-fiber recordings from two somatic (sciatic and saphenous) and one autonomic (vagal) nerves harvested from mice. Action potentials were evoked on one end of the nerve and recorded on the other end from teased nerve filaments, i.e., single-fiber recordings. ePNS was delivered in the middle of the nerve trunk using a glass suction electrode at frequencies of 5, 10, 50, 100, 500, and 1000 Hz. Results Suprathreshold ePNS reversibly blocks axonal neural transmission of both thinly myelinated Aδ-fiber axons and unmyelinated C-fiber axons. ePNS leads to a progressive decrease in conduction velocity (CV) until transmission blockage, suggesting activity-dependent conduction slowing. The blocking efficiency is dependent on the axonal conduction velocity, with Aδ-fibers efficiently blocked by 50-1000 Hz stimulation and C-fibers blocked by 10-50 Hz. The corresponding NEURON simulation of action potential transmission indicates that the disrupted transmembrane sodium and potassium concentration gradients underly the transmission block by the ePNS. Discussion The current study provides direct evidence of reversible Aδ- and C-fiber transmission blockage by low-frequency (<100 Hz) electrical stimulation of the nerve trunk, a previously overlooked mechanism that can be harnessed to enhance the therapeutic effect of ePNS in treating neurological disorders.
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Affiliation(s)
| | | | | | | | | | - Bin Feng
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, United States
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Kaye AD, Everett ES, Lehuquet AM, Mason JW, Maitski R, Plessala MJ, Barrie S, Baptiste CJ, Mychaskiw G, Ahmadzadeh S, Shekoohi S, Varrassi G. Frontiers in Acute Pain Management: Emerging Concepts in Pain Pathways and the Role of VX-548 as a Novel NaV1.8 Inhibitor: A Narrative Review. Curr Pain Headache Rep 2024:10.1007/s11916-024-01295-7. [PMID: 38963514 DOI: 10.1007/s11916-024-01295-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2024] [Indexed: 07/05/2024]
Abstract
PURPOSE OF REVIEW Despite ongoing research into alternative postsurgical pain treatments, opioids remain widely used analgesics regardless of associated adverse effects, including dependence and overdose, as demonstrated throughout the current opioid crisis. This is likely related to a failure in proving the efficacy of alternative analgesics in clinical trials, despite strong evidence supporting the potential for effective analgesia through in vitro studies. While NaV1.7 and NaV1.8 channels have shown to be key components of pain perception, studies regarding pharmacological agents utilizing these channels as targets have largely failed to demonstrate the efficacy of these proposed analgesics when compared to current multimodal pain treatment regimens. RECENT FINDINGS However, the novel NaV1.8 channel inhibitor, VX-548 has surpassed previously studied NaV1.8 inhibitors in clinical trials and continues to hold promise of a novel efficacious analgesic to potentially be utilized in multimodal pain treatment on postsurgical patients. Additionally, NaV1.8 is encoded by the SCN10A, which has been shown to be minimally expressed in the brain, suggesting a lower likelihood of adverse effects in the CNS, including dependence and abuse. Novel pharmacologic analgesics that are efficacious without the significant side effects associated with opioids have lacked meaningful development. However, recent clinical trials have shown promising results in the safety and efficacy of the pharmacological agent VX-548. Still, more clinical trials directly comparing the efficacy of VX-548 to standard of care post-surgical drugs, including opioids like morphine and hydromorphone are needed to demonstrate the long-term viability of the agent replacing current opioids with an unfavorable side effect profile.
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Affiliation(s)
- Alan D Kaye
- Departments of Anesthesiology and Pharmacology, Toxicology, and Neurosciences, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, 71103, USA
| | - Erin S Everett
- Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA, 70112, USA
| | - Arianna M Lehuquet
- Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA, 70112, USA
| | - Joseph W Mason
- LSU Health Sciences Center New Orleans School of Medicine, 1901 Gravier St, New Orleans, LA, USA
| | - Rebecca Maitski
- LSU Health Sciences Center New Orleans School of Medicine, 1901 Gravier St, New Orleans, LA, USA
| | - Michael J Plessala
- LSU Health Sciences Center New Orleans School of Medicine, 1901 Gravier St, New Orleans, LA, USA
| | - Sonnah Barrie
- Department of Anesthesiology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA, 71103, USA
| | - Carlo Jean Baptiste
- Department of Anesthesiology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA, 71103, USA
| | - George Mychaskiw
- Department of Anesthesiology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA, 71103, USA
| | - Shahab Ahmadzadeh
- Department of Anesthesiology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA, 71103, USA
| | - Sahar Shekoohi
- Department of Anesthesiology, Louisiana State University Health Sciences Center at Shreveport, Shreveport, LA, 71103, USA.
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10
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Krogman WL, Woodard T, McKay RSF. Anesthetic Mechanisms: Synergistic Interactions With Lipid Rafts and Voltage-Gated Sodium Channels. Anesth Analg 2024; 139:92-106. [PMID: 37968836 DOI: 10.1213/ane.0000000000006738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Despite successfully utilizing anesthetics for over 150 years, the mechanism of action remains relatively unknown. Recent studies have shown promising results, but due to the complex interactions between anesthetics and their targets, there remains a clear need for further mechanistic research. We know that lipophilicity is directly connected to anesthetic potency since lipid solubility relates to anesthetic partition into the membrane. However, clinically relevant concentrations of anesthetics do not significantly affect lipid bilayers but continue to influence various molecular targets. Lipid rafts are derived from liquid-ordered phases of the plasma membrane that contain increased concentrations of cholesterol and sphingomyelin and act as staging platforms for membrane proteins, including ion channels. Although anesthetics do not perturb membranes at clinically relevant concentrations, they have recently been shown to target lipid rafts. In this review, we summarize current research on how different types of anesthetics-local, inhalational, and intravenous-bind and affect both lipid rafts and voltage-gated sodium channels, one of their major targets, and how those effects synergize to cause anesthesia and analgesia. Local anesthetics block voltage-gated sodium channel pores while also disrupting lipid packing in ordered membranes. Inhalational anesthetics bind to the channel pore and the voltage-sensing domain while causing an increase in the number, size, and diameter of lipid rafts. Intravenous anesthetics bind to the channel primarily at the voltage-sensing domain and the selectivity filter, while causing lipid raft perturbation. These changes in lipid nanodomain structure possibly give proteins access to substrates that have translocated as a result of these structural alterations, resulting in lipid-driven anesthesia. Overall, anesthetics can impact channel activity either through direct interaction with the channel, indirectly through the lipid raft, or both. Together, these result in decreased sodium ion flux into the cell, disrupting action potentials and producing anesthetic effects. However, more research is needed to elucidate the indirect mechanisms associated with channel disruption through the lipid raft, as not much is known about anionic lipid products and their influence over voltage-gated sodium channels. Anesthetics' effect on S-palmitoylation, a promising mechanism for direct and indirect influence over voltage-gated sodium channels, is another auspicious avenue of research. Understanding the mechanisms of different types of anesthetics will allow anesthesiologists greater flexibility and more specificity when treating patients.
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Affiliation(s)
- William L Krogman
- From the Department of Anesthesiology, University of Kansas School of Medicine - Wichita, Wichita, Kansas
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11
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Zhang H, Chen Y, Huang J, Sun W. A simple and sensitive ultra-high performance liquid chromatography tandem mass spectrometry method for the quantitative analysis of VX-548 in monkey plasma: Method validation and application to pharmacokinetic study. Biomed Chromatogr 2024; 38:e5907. [PMID: 38783548 DOI: 10.1002/bmc.5907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
VX-548 is an orally active and highly selective NaV 1.8 inhibitor that is undergoing development for the treatment of acute pain. The aim of this study was to develop a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the measurement of VX-548 in monkey plasma. VX-548 was extracted from the plasma using acetonitrile-mediated protein precipitation. The quantitative analysis was performed on a Thermo Vantage TSQ mass spectrometer with ibrutinib as an internal standard. Chromatography was performed on a Waters ACQUITY UPLC BEH C18 column with 0.1% aqueous formic acid and acetonitrile as mobile phase. The precursor-to-product ion transitions were m/z 474.2 > 165.0 and m/z 441.2 > 138.1 for VX-548 and internal standard, respectively. This developed method was successfully validated in the concentration range of 1-1000 ng/mL. The calibration curve showed excellent linearity with a correlation coefficient of >0.999. The precision expressed as relative standard deviation (RSD) was <8.4%, whereas the accuracy denoted as relative error (RE) ranged from -5.0% to 9.1%. The mean recovery was >84%. VX-548 was stable in monkey plasma after storage under certain conditions. The validated method was successfully applied to the pharmacokinetic study of VX-548 in monkey plasma after single oral (2 mg/kg) and intravenous (1 mg/kg) administrations.
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Affiliation(s)
- Huiying Zhang
- Department of Pharmacy, Xuzhou Central Hospital, Xuzhou, China
| | - Yonggang Chen
- Department of Pharmacy, Xuzhou Central Hospital, Xuzhou, China
| | - Jing Huang
- Department of Pharmacy, Xuzhou Central Hospital, Xuzhou, China
| | - Wenfei Sun
- Department of Pharmacy, Xuzhou Central Hospital, Xuzhou, China
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12
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Heinle JW, Dalessio S, Janicki P, Ouyang A, Vrana KE, Ruiz-Velasco V, Coates MD. Insights into the voltage-gated sodium channel, Na V1.8, and its role in visceral pain perception. Front Pharmacol 2024; 15:1398409. [PMID: 38855747 PMCID: PMC11158627 DOI: 10.3389/fphar.2024.1398409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 04/29/2024] [Indexed: 06/11/2024] Open
Abstract
Pain is a major issue in healthcare throughout the world. It remains one of the major clinical issues of our time because it is a common sequela of numerous conditions, has a tremendous impact on individual quality of life, and is one of the top drivers of cost in medicine, due to its influence on healthcare expenditures and lost productivity in those affected by it. Patients and healthcare providers remain desperate to find new, safer and more effective analgesics. Growing evidence indicates that the voltage-gated sodium channel Nav1.8 plays a critical role in transmission of pain-related signals throughout the body. For that reason, this channel appears to have strong potential to help develop novel, more selective, safer, and efficacious analgesics. However, many questions related to the physiology, function, and clinical utility of Nav1.8 remain to be answered. In this article, we discuss the latest studies evaluating the role of Nav1.8 in pain, with a particular focus on visceral pain, as well as the steps taken thus far to evaluate its potential as an analgesic target. We also review the limitations of currently available studies related to this topic, and describe the next scientific steps that have already been undertaken, or that will need to be pursued, to fully unlock the capabilities of this potential therapeutic target.
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Affiliation(s)
- J. Westley Heinle
- Division of Gastroenterology and Hepatology, Penn State College of Medicine, Hershey, PA, United States
| | - Shannon Dalessio
- Division of Gastroenterology and Hepatology, Penn State College of Medicine, Hershey, PA, United States
| | - Piotr Janicki
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, United States
| | - Ann Ouyang
- Division of Gastroenterology and Hepatology, Penn State College of Medicine, Hershey, PA, United States
| | - Kent E. Vrana
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
| | - Victor Ruiz-Velasco
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, United States
| | - Matthew D. Coates
- Division of Gastroenterology and Hepatology, Penn State College of Medicine, Hershey, PA, United States
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
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13
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Kamei T, Kudo T, Yamane H, Ishibashi F, Takada Y, Honda S, Maezawa Y, Ikeda K, Oyamada Y. Unique electrophysiological property of a novel Nav1.7, Nav1.8, and Nav1.9 sodium channel blocker, ANP-230. Biochem Biophys Res Commun 2024; 721:150126. [PMID: 38776832 DOI: 10.1016/j.bbrc.2024.150126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 04/28/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Voltage-gated sodium channel subtypes, Nav1.7, Nav1.8, and Nav1.9 are predominantly expressed in peripheral sensory neurons. Recent genetic studies have revealed that they are involved in pathological pain processing and that the blockade of Nav1.7, Nav1.8, or Nav1.9 will become a promising pharmacotherapy especially for neuropathic pain. A growing number of drug discovery programs have targeted either of the subtypes to obtain a selective inhibitor which can provide pain relief without affecting the cardiovascular and central nervous systems, though none of them has been approved yet. Here we describe the in vitro characteristics of ANP-230, a novel sodium channel blocker under clinical development. Surprisingly, ANP-230 was shown to block three pain-related subtypes, human Nav1.7, Nav1.8, and Nav1.9 with similar potency, but had only low inhibitory activity to human cardiac Nav1.5 channel and rat central Nav channels. The voltage clamp experiments using different step pulse protocols revealed that ANP-230 had a "tonic block" mode of action without state- and use-dependency. In addition, ANP-230 caused a depolarizing shift of the activation curve and decelerated gating kinetics in human Nav1.7-stably expressing cells. The depolarizing shift of activation curve was commonly observed in human Nav1.8-stably expressing cells as well as rat dorsal root ganglion neurons. These data suggested a quite unique mechanism of Nav channel inhibition by ANP-230. Finally, ANP-230 reduced excitability of rat dorsal root ganglion neurons in a concentration dependent manner. Collectively, these promising results indicate that ANP-230 could be a potent drug for neuropathic pain.
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Affiliation(s)
- Tatsuya Kamei
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; Regenerative & Cellular Medicine Kobe Center, Sumitomo Pharma Co., Ltd., Kobe, 650-0047, Japan.
| | - Takehiro Kudo
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan
| | - Hana Yamane
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; Regenerative & Cellular Medicine Kobe Center, Sumitomo Pharma Co., Ltd., Kobe, 650-0047, Japan
| | - Fumiaki Ishibashi
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; Platform Technology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan
| | - Yoshinori Takada
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; Global Corporate Strategy, Sumitomo Pharma Co., Ltd., Tokyo, 104-8356, Japan
| | - Shigeyuki Honda
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; Sumika Chemical Analysis Service, Ltd., Osaka, 554-0022, Japan
| | - Yasuyo Maezawa
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan
| | - Kazuhito Ikeda
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; Platform Technology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan
| | - Yoshihiro Oyamada
- Pharmacology Research Unit, Research Division, Sumitomo Pharma Co., Ltd., Osaka, 554-0022, Japan; AlphaNavi Pharma Inc., Osaka, 564-0053, Japan
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14
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Xie YF, Yang J, Ratté S, Prescott SA. Similar excitability through different sodium channels and implications for the analgesic efficacy of selective drugs. eLife 2024; 12:RP90960. [PMID: 38687187 PMCID: PMC11060714 DOI: 10.7554/elife.90960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024] Open
Abstract
Nociceptive sensory neurons convey pain-related signals to the CNS using action potentials. Loss-of-function mutations in the voltage-gated sodium channel NaV1.7 cause insensitivity to pain (presumably by reducing nociceptor excitability) but clinical trials seeking to treat pain by inhibiting NaV1.7 pharmacologically have struggled. This may reflect the variable contribution of NaV1.7 to nociceptor excitability. Contrary to claims that NaV1.7 is necessary for nociceptors to initiate action potentials, we show that nociceptors can achieve similar excitability using different combinations of NaV1.3, NaV1.7, and NaV1.8. Selectively blocking one of those NaV subtypes reduces nociceptor excitability only if the other subtypes are weakly expressed. For example, excitability relies on NaV1.8 in acutely dissociated nociceptors but responsibility shifts to NaV1.7 and NaV1.3 by the fourth day in culture. A similar shift in NaV dependence occurs in vivo after inflammation, impacting ability of the NaV1.7-selective inhibitor PF-05089771 to reduce pain in behavioral tests. Flexible use of different NaV subtypes exemplifies degeneracy - achieving similar function using different components - and compromises reliable modulation of nociceptor excitability by subtype-selective inhibitors. Identifying the dominant NaV subtype to predict drug efficacy is not trivial. Degeneracy at the cellular level must be considered when choosing drug targets at the molecular level.
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Affiliation(s)
- Yu-Feng Xie
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
| | - Jane Yang
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
- Institute of Biomedical Engineering, University of TorontoTorontoCanada
| | - Stéphanie Ratté
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
| | - Steven A Prescott
- Neurosciences and Mental Health, The Hospital for Sick ChildrenTorontoCanada
- Institute of Biomedical Engineering, University of TorontoTorontoCanada
- Department of Physiology, University of TorontoTorontoCanada
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15
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Tian J, Bavencoffe AG, Zhu MX, Walters ET. Readiness of nociceptor cell bodies to generate spontaneous activity results from background activity of diverse ion channels and high input resistance. Pain 2024; 165:893-907. [PMID: 37862056 PMCID: PMC10950548 DOI: 10.1097/j.pain.0000000000003091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/09/2023] [Indexed: 10/21/2023]
Abstract
ABSTRACT Nociceptor cell bodies generate "spontaneous" discharge that can promote ongoing pain in persistent pain conditions. Little is known about the underlying mechanisms. Recordings from nociceptor cell bodies (somata) dissociated from rodent and human dorsal root ganglia have shown that previous pain in vivo is associated with low-frequency discharge controlled by irregular depolarizing spontaneous fluctuations of membrane potential (DSFs), likely produced by transient inward currents across the somal input resistance. Using mouse nociceptors, we show that DSFs are associated with high somal input resistance over a wide range of membrane potentials, including depolarized levels where DSFs approach action potential (AP) threshold. Input resistance and both the amplitude and frequency of DSFs were increased in neurons exhibiting spontaneous activity. Ion substitution experiments indicated that the depolarizing phase of DSFs is generated by spontaneous opening of channels permeable to Na + or Ca 2+ and that Ca 2+ -permeable channels are especially important for larger DSFs. Partial reduction of the amplitude or frequency of DSFs by perfusion of pharmacological inhibitors indicated small but significant contributions from Nav1.7, Nav1.8, TRPV1, TRPA1, TRPM4, and N-type Ca 2+ channels. Less specific blockers suggested a contribution from NALCN channels, and global knockout suggested a role for Nav1.9. The combination of high somal input resistance plus background activity of diverse ion channels permeable to Na + or Ca 2+ produces DSFs that are poised to reach AP threshold if resting membrane potential depolarizes, AP threshold decreases, or DSFs become enhanced-all of which can occur under painful neuropathic and inflammatory conditions.
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Affiliation(s)
- Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Alexis G. Bavencoffe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
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16
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Zhang L, Tian J, Lin Z, Dong Z. Efficient Sodium Transmembrane Permeation through Helically Folded Nanopores with Natural Channel-Like Ion Selectivity. J Am Chem Soc 2024; 146:8500-8507. [PMID: 38483183 DOI: 10.1021/jacs.3c14736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The selective transmembrane permeation of sodium ions achieved by biomimetic chemistry shows great potential to solve the problem of sodium ion transport blockade in diseases, but its implementation faces enormous difficulties. Herein, we design and synthesize a series of helically folded nanopores by employing a quinoline-oxadiazole structural sequence to finely replicate the pentahydrate structure of sodium ions. Surprisingly, these nanopores are capable of achieving sodium transmembrane permeation with ion selectivity at the level of natural sodium channels, as observed in rationally designed nanopores (M1-M5) with Na+/K+ ion selectivity ratio of up to 20.4. Moreover, slight structural variations in nanopore structures can switch ion transport modes between the channel and carrier. We found that, compared to the carrier mode, the channel mode not only transports ions faster but also has higher ion selectivity during transmembrane conduction, clearly illustrating that the trade-off phenomenon between ion selectivity and transport activity does not occur between the two transport modes of channel and carrier. At the same time, we also found that the spatial position and numbers of coordination sites are crucial for the sodium ion selectivity of the nanopores. Moreover, carrier M1 reported in this work is totally superior to the commercial Na+ carrier ETH2120, especially in terms of Na+/K+ ion selectivity, thus being a potentially practical Na+ carrier. Our study provides a new paradigm on the rational design of sodium-specific synthetic nanopores, which will open up the possibility for the application of artificial sodium-specific transmembrane permeation in biomedicine and disease treatment.
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Affiliation(s)
- Lei Zhang
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
| | - Jun Tian
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
| | - Ze Lin
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
| | - Zeyuan Dong
- State Key Laboratory of Supramolecular Structure and Materials, and Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun 130012, China
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17
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Kapur MM, Soliman M, Blanke EN, Herold PB, Janicki PK, Vrana KE, Coates MD, Ruiz-Velasco V. Heterologous expression of the human wild-type and variant Na V 1.8 (A1073V) in rat sensory neurons. Neurogastroenterol Motil 2024; 36:e14748. [PMID: 38263802 PMCID: PMC10922522 DOI: 10.1111/nmo.14748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/28/2023] [Accepted: 01/16/2024] [Indexed: 01/25/2024]
Abstract
BACKGROUND Silent inflammatory bowel disease (IBD) is a condition in which individuals with the active disease experience minor to no pain. Voltage-gated Na+ (NaV ) channels expressed in sensory neurons play a major role in pain perception. Previously, we reported that a NaV 1.8 genetic polymorphism (A1073V, rs6795970) was more common in a cohort of silent IBD patients. The expression of this variant (1073V) in rat sympathetic neurons activated at more depolarized potentials when compared to the more common variant (1073A). In this study, we investigated whether expression of either NaV 1.8 variant in rat sensory neurons would exhibit different biophysical characteristics than previously observed in sympathetic neurons. METHODS Endogenous NaV 1.8 channels were first silenced in DRG neurons and then either 1073A or 1073V human NaV 1.8 cDNA constructs were transfected. NaV 1.8 currents were recorded with the whole-cell patch-clamp technique. KEY RESULTS The results indicate that 1073A and 1073V NaV 1.8 channels exhibited similar activation values. However, the slope factor (k) for activation determined for this same group of neurons decreased by 5 mV, suggesting an increase in voltage sensitivity. Comparison of inactivation parameters indicated that 1073V channels were shifted to more depolarized potentials than 1073A-expressing neurons, imparting a proexcitatory characteristic. CONCLUSIONS AND INFERENCES These findings differ from previous observations in other expression models and underscore the challenges with heterologous expression systems. Therefore, the use of human sensory neurons derived from induced pluripotent stem cells may help address these inconsistencies and better determine the effect of the polymorphism present in IBD patients.
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Affiliation(s)
- Maryam M. Kapur
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
| | - Marwa Soliman
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
| | - Emily N. Blanke
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
| | - Paul B. Herold
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
| | - Piotr K. Janicki
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
| | - Kent E. Vrana
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, USA
| | - Matthew D. Coates
- Department of Gastroenterology and Hepatology, Penn State College of Medicine, Hershey, PA, USA
| | - Victor Ruiz-Velasco
- Department of Anesthesiology and Perioperative Medicine, Penn State College of Medicine, Hershey, PA, USA
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18
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Gilchrist JM, Yang ND, Jiang V, Moyer BD. Pharmacologic Characterization of LTGO-33, a Selective Small Molecule Inhibitor of the Voltage-Gated Sodium Channel Na V1.8 with a Unique Mechanism of Action. Mol Pharmacol 2024; 105:233-249. [PMID: 38195157 DOI: 10.1124/molpharm.123.000789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/28/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024] Open
Abstract
Discovery and development of new molecules directed against validated pain targets is required to advance the treatment of pain disorders. Voltage-gated sodium channels (NaVs) are responsible for action potential initiation and transmission of pain signals. NaV1.8 is specifically expressed in peripheral nociceptors and has been genetically and pharmacologically validated as a human pain target. Selective inhibition of NaV1.8 can ameliorate pain while minimizing effects on other NaV isoforms essential for cardiac, respiratory, and central nervous system physiology. Here we present the pharmacology, interaction site, and mechanism of action of LTGO-33, a novel NaV1.8 small molecule inhibitor. LTGO-33 inhibited NaV1.8 in the nM potency range and exhibited over 600-fold selectivity against human NaV1.1-NaV1.7 and NaV1.9. Unlike prior reported NaV1.8 inhibitors that preferentially interacted with an inactivated state via the pore region, LTGO-33 was state-independent with similar potencies against closed and inactivated channels. LTGO-33 displayed species specificity for primate NaV1.8 over dog and rodent NaV1.8 and inhibited action potential firing in human dorsal root ganglia neurons. Using chimeras combined with mutagenesis, the extracellular cleft of the second voltage-sensing domain was identified as the key site required for channel inhibition. Biophysical mechanism of action studies demonstrated that LTGO-33 inhibition was relieved by membrane depolarization, suggesting the molecule stabilized the deactivated state to prevent channel opening. LTGO-33 equally inhibited wild-type and multiple NaV1.8 variants associated with human pain disorders. These collective results illustrate LTGO-33 inhibition via both a novel interaction site and mechanism of action previously undescribed in NaV1.8 small molecule pharmacologic space. SIGNIFICANCE STATEMENT: NaV1.8 sodium channels primarily expressed in peripheral pain-sensing neurons represent a validated target for the development of novel analgesics. Here we present the selective small molecule NaV1.8 inhibitor LTGO-33 that interdicts a distinct site in a voltage-sensor domain to inhibit channel opening. These results inform the development of new analgesics for pain disorders.
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Affiliation(s)
| | - Nien-Du Yang
- Latigo Biotherapeutics, Inc., Thousand Oaks, California
| | | | - Bryan D Moyer
- Latigo Biotherapeutics, Inc., Thousand Oaks, California
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19
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Cho JH, Jang IS. Ibuprofen modulates tetrodotoxin-resistant persistent Na + currents at acidic pH in rat trigeminal ganglion neurons. Eur J Pharmacol 2023; 961:176218. [PMID: 37992887 DOI: 10.1016/j.ejphar.2023.176218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023]
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to relieve various symptoms such as headache, arthralgia, and dental pain. While the primary mechanism of NSAID-based pain relief is the inhibition of cyclooxygenase-2, several NSAIDs also modulate other molecular targets related to nociceptive transmission such as voltage-gated Na+ channels. In the present study, we examined the effects of NSAIDs on persistent Na+ current (INaP) mediated by tetrodotoxin-resistant (TTX-R) Na+ channels in small-to medium-sized trigeminal ganglion neurons using a whole-cell patch-clamp technique. At clinically relevant concentrations, all propionic acid derivatives tested (ibuprofen, naproxen, fenoprofen, and flurbiprofen) preferentially inhibited the TTX-R INaP. The inhibition was more potent at acidic extracellular pH (pH 6.5) than at normal pH (pH 7.4). Other NSAIDs, such as ketorolac, piroxicam, and aspirin, had a negligible effect on the TTX-R INaP. Ibuprofen both accelerated the onset of inactivation and retarded the recovery from inactivation of TTX-R Na+ channels at acidic extracellular pH. However, all NSAIDs tested in this study had minor effects on voltage-gated K+ currents, as well as hyperpolarization-activated and cyclic nucleotide-gated cation currents, at both acidic and normal extracellular pH. Under current-clamp conditions, ibuprofen decreased the number of action potentials elicited by depolarizing current stimuli at acidic (pH 6.5) extracellular pH. Considering that extracellular pH falls as low as 5.5 in inflamed tissues, TTX-R INaP inhibition could be a mechanism by which ibuprofen and propionic acid derivative NSAIDs modulate inflammatory pain.
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Affiliation(s)
- Jin-Hwa Cho
- Department of Pharmacology, School of Dentistry, Republic of Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu, 41940, Republic of Korea.
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20
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Loose S, Lischka A, Kuehs S, Nau C, Heinemann SH, Kurth I, Leipold E. Peripheral temperature dysregulation associated with functionally altered Na V1.8 channels. Pflugers Arch 2023; 475:1343-1355. [PMID: 37695396 PMCID: PMC10567936 DOI: 10.1007/s00424-023-02856-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/23/2023] [Accepted: 09/01/2023] [Indexed: 09/12/2023]
Abstract
The voltage-gated sodium channel NaV1.8 is prominently expressed in the soma and axons of small-caliber sensory neurons, and pathogenic variants of the corresponding gene SCN10A are associated with peripheral pain and autonomic dysfunction. While most disease-associated SCN10A variants confer gain-of-function properties to NaV1.8, resulting in hyperexcitability of sensory neurons, a few affect afferent excitability through a loss-of-function mechanism. Using whole-exome sequencing, we here identify a rare heterozygous SCN10A missense variant resulting in alteration p.V1287I in NaV1.8 in a patient with a 15-year history of progressively worsening temperature dysregulation in the distal extremities, particularly in the feet. Further symptoms include increasingly intensifying tingling and numbness in the fingers and increased sweating. To assess the impact of p.V1287I on channel function, we performed voltage-clamp recordings demonstrating that the alteration confers loss- and gain-of-function characteristics to NaV1.8 characterized by a right-shifted voltage dependence of channel activation and inactivation. Current-clamp recordings from transfected mouse dorsal root ganglion neurons further revealed that NaV1.8-V1287I channels broaden the action potentials of sensory neurons and increase their firing rates in response to depolarizing current stimulations, indicating a gain-of-function mechanism of the variant at the cellular level in a heterozygous setting. The data support the hypothesis that the properties of NaV1.8 p.V1287I are causative for the patient's symptoms and that nonpainful peripheral paresthesias should be considered part of the clinical spectrum of NaV1.8-associated disorders.
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Affiliation(s)
- Simon Loose
- Department of Anesthesiology and Intensive Care & CBBM - Center of Brain, Behavior and Metabolism, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany
| | - Annette Lischka
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Samuel Kuehs
- Department of Anesthesiology and Intensive Care & CBBM - Center of Brain, Behavior and Metabolism, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany
| | - Carla Nau
- Department of Anesthesiology and Intensive Care & CBBM - Center of Brain, Behavior and Metabolism, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany
| | - Stefan H Heinemann
- Center for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University Jena and Jena University Hospital, Jena, Germany
| | - Ingo Kurth
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Enrico Leipold
- Department of Anesthesiology and Intensive Care & CBBM - Center of Brain, Behavior and Metabolism, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany.
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21
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Yang R, Wang QQ, Feng Y, Li XH, Li GX, She FL, Zhu XJ, Li CL. Over-expression of miR-3584-5p Represses Nav1.8 Channel Aggravating Neuropathic Pain caused by Chronic Constriction Injury. Mol Neurobiol 2023; 60:5237-5255. [PMID: 37280408 DOI: 10.1007/s12035-023-03394-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 05/18/2023] [Indexed: 06/08/2023]
Abstract
Nav1.8, a tetrodotoxin-resistant voltage-gated sodium channels (VGSCs) subtype encoded by SCN10A, which plays an important role in the production and transmission of peripheral neuropathic pain signals. Studies have shown that VGSCs may be key targets of MicroRNAs (miRNAs) in the regulation of neuropathic pain. In our study, bioinformatics analysis showed that the targeting relationship between miR-3584-5p and Nav1.8 was the most closely. The purpose of this study was to investigate the roles of miR-3584-5p and Nav1.8 in neuropathic pain. The effects of miR-3584-5p on chronic constriction injury (CCI)-induced neuropathic pain in rats was investigated by intrathecal injection of miR-3584-5p agomir (an agonist, 20 μM, 15 μL) or antagomir (an antagonist, 20 μM, 15 μL). The results showed that over-expression of miR-3584-5p aggravated neuronal injury by hematoxylin-eosin (H&E) staining and mechanical/thermal hypersensitivity in CCI rats. MiR-3584-5p indirectly inhibited the expression of Nav1.8 by up-regulating the expression of key proteins in the ERK5/CREB signaling pathway, and also inhibited the current density of the Nav1.8 channel, changed its channel dynamics characteristic, thereby accelerating the transmission of pain signals, and further aggravating pain. Similarly, in PC12 and SH-SY5Y cell cultures, miR-3584-5p increased the level of reactive oxygen species (ROS) and inhibited mitochondrial membrane potential (Δψm) in the mitochondrial pathway, decreased the ratio of apoptosis-related factor Bcl-2/Bax, and thus promoted neuronal apoptosis. In brief, over-expression of miR-3584-5p aggravates neuropathic pain by directly inhibiting the current density of Nav1.8 channel and altering its channel dynamics, or indirectly inhibiting Nav1.8 expression through ERK5/CREB pathway, and promoting apoptosis through mitochondrial pathway.
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Affiliation(s)
- Ran Yang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Qian-Qian Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Yuan Feng
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Xue-Hao Li
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Gui-Xia Li
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Feng-Lin She
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Xi-Jin Zhu
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China
| | - Chun-Li Li
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, Liaoning, People's Republic of China.
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22
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Haroun R, Gossage SJ, Luiz AP, Arcangeletti M, Sikandar S, Zhao J, Cox JJ, Wood JN. Chemogenetic Silencing of Na V1.8-Positive Sensory Neurons Reverses Chronic Neuropathic and Bone Cancer Pain in FLEx PSAM 4-GlyR Mice. eNeuro 2023; 10:ENEURO.0151-23.2023. [PMID: 37679042 PMCID: PMC10523839 DOI: 10.1523/eneuro.0151-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/15/2023] [Accepted: 08/23/2023] [Indexed: 09/09/2023] Open
Abstract
Drive from peripheral neurons is essential in almost all pain states, but pharmacological silencing of these neurons to effect analgesia has proved problematic. Reversible gene therapy using long-lived chemogenetic approaches is an appealing option. We used the genetically activated chloride channel PSAM4-GlyR to examine pain pathways in mice. Using recombinant AAV9-based delivery to sensory neurons, we found a reversal of acute pain behavior and diminished neuronal activity using in vitro and in vivo GCaMP imaging on activation of PSAM4-GlyR with varenicline. A significant reduction in inflammatory heat hyperalgesia and oxaliplatin-induced cold allodynia was also observed. Importantly, there was no impairment of motor coordination, but innocuous von Frey sensation was inhibited. We generated a transgenic mouse that expresses a CAG-driven FLExed PSAM4-GlyR downstream of the Rosa26 locus that requires Cre recombinase to enable the expression of PSAM4-GlyR and tdTomato. We used NaV1.8 Cre to examine the role of predominantly nociceptive NaV1.8+ neurons in cancer-induced bone pain (CIBP) and neuropathic pain caused by chronic constriction injury (CCI). Varenicline activation of PSAM4-GlyR in NaV1.8-positive neurons reversed CCI-driven mechanical, thermal, and cold sensitivity. Additionally, varenicline treatment of mice with CIBP expressing PSAM4-GlyR in NaV1.8+ sensory neurons reversed cancer pain as assessed by weight-bearing. Moreover, when these mice were subjected to acute pain assays, an elevation in withdrawal thresholds to noxious mechanical and thermal stimuli was detected, but innocuous mechanical sensations remained unaffected. These studies confirm the utility of PSAM4-GlyR chemogenetic silencing in chronic pain states for mechanistic analysis and potential future therapeutic use.
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Affiliation(s)
- Rayan Haroun
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
| | - Samuel J Gossage
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
| | - Ana Paula Luiz
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
| | - Manuel Arcangeletti
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
| | - Shafaq Sikandar
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Jing Zhao
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
| | - James J Cox
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
| | - John N Wood
- Wolfson Institute for Biomedical Research, Division of Medicine, University College London, London WC1E 6BT, United Kingdom
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23
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Kim G, Kim H, Jang IS. Trichloroethanol, an active metabolite of chloral hydrate, modulates tetrodotoxin-resistant Na + channels in rat nociceptive neurons. BMC Anesthesiol 2023; 23:145. [PMID: 37120567 PMCID: PMC10148498 DOI: 10.1186/s12871-023-02105-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/22/2023] [Indexed: 05/01/2023] Open
Abstract
BACKGROUND Chloral hydrate is a sedative-hypnotic drug widely used for relieving fear and anxiety in pediatric patients. However, mechanisms underlying the chloral hydrate-mediated analgesic action remain unexplored. Therefore, we investigated the effect of 2',2',2'-trichloroethanol (TCE), the active metabolite of chloral hydrate, on tetrodotoxin-resistant (TTX-R) Na+ channels expressed in nociceptive sensory neurons. METHODS The TTX-R Na+ current (INa) was recorded from acutely isolated rat trigeminal ganglion neurons using the whole-cell patch-clamp technique. RESULTS Trichloroethanol decreased the peak amplitude of transient TTX-R INa in a concentration-dependent manner and potently inhibited persistent components of transient TTX-R INa and slow voltage-ramp-induced INa at clinically relevant concentrations. Trichloroethanol exerted multiple effects on various properties of TTX-R Na+ channels; it (1) induced a hyperpolarizing shift on the steady-state fast inactivation relationship, (2) increased use-dependent inhibition, (3) accelerated the onset of inactivation, and (4) retarded the recovery of inactivated TTX-R Na+ channels. Under current-clamp conditions, TCE increased the threshold for the generation of action potentials, as well as decreased the number of action potentials elicited by depolarizing current stimuli. CONCLUSIONS Our findings suggest that chloral hydrate, through its active metabolite TCE, inhibits TTX-R INa and modulates various properties of these channels, resulting in the decreased excitability of nociceptive neurons. These pharmacological characteristics provide novel insights into the analgesic efficacy exerted by chloral hydrate.
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Affiliation(s)
- Gimin Kim
- Department of Pediatric Dentistry, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea
| | - Hyunjung Kim
- Department of Pediatric Dentistry, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Kyungpook National University, 2177 Dalgubeol-daero, Jung-gu, Daegu, 41940, Republic of Korea.
- Brain Science & Engineering Institute, Kyungpook National University, Daegu, 41940, Republic of Korea.
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24
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Ovsepian SV, Waxman SG. Gene therapy for chronic pain: emerging opportunities in target-rich peripheral nociceptors. Nat Rev Neurosci 2023; 24:252-265. [PMID: 36658346 DOI: 10.1038/s41583-022-00673-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2022] [Indexed: 01/20/2023]
Abstract
With sweeping advances in precision delivery systems and manipulation of the genomes and transcriptomes of various cell types, medical biotechnology offers unprecedented selectivity for and control of a wide variety of biological processes, forging new opportunities for therapeutic interventions. This perspective summarizes state-of-the-art gene therapies enabled by recent innovations, with an emphasis on the expanding universe of molecular targets that govern the activity and function of primary sensory neurons and which might be exploited to effectively treat chronic pain.
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Affiliation(s)
- Saak V Ovsepian
- School of Science, Faculty of Engineering and Science, University of Greenwich London, Chatham Maritime, UK.
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA.
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25
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Li Z, Gan Y, Kang T, Zhao Y, Huang T, Chen Y, Liu J, Ke B. Camphor Attenuates Hyperalgesia in Neuropathic Pain Models in Mice. J Pain Res 2023; 16:785-795. [PMID: 36925623 PMCID: PMC10013580 DOI: 10.2147/jpr.s398607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/21/2023] [Indexed: 03/12/2023] Open
Abstract
Background The treatment of neuropathic pain is still a major troublesome clinical problem. The existing therapeutic drugs have limited analgesic effect and obvious adverse reactions, which presents opportunities and challenges for the development of new analgesic drugs. Camphor, a kind of monoterpene, has been shown anti-inflammatory and analgesic effects in traditional Chinese medicine. But we know little about its effect in neuropathic pain. In this article, We have verified the reliable analgesic effect of camphor in the neuropathic pain model caused by different predispositions. Methods The nociceptive response of mice was induced by transient receptor potential A1 (TRPA1) agonist to verify the effect of camphor on the nociceptive response. Multiple paclitaxel (PTX) injection models, Single oxaliplatin (OXA) injection models, Chronic constriction injury (CCI) models and Streptozotocin-induced (STZ) diabetic neuropathic pain models were used in this study. We verified the analgesic effect of camphor in mice by acetone test and conditioned place aversion test. At the same time, comparing the adverse reaction of nervous system between camphor and pregabalin at equivalent dose in locomotor activity test and rotarod test. Using patch clamp to verify the effect of camphor on dorsal root ganglion (DRG) excitability. Results In behavioral test, compared with vehicle group, camphor significantly reduced the spontaneous nociception caused by TRPA1 agonist-formalina and allyl isothiocyanate (AITC). Compared with vehicle group, camphor significantly reduced the flinching and licking time in neuropathic pain model mice, including PTX, OXA, STZ and CCI induced peripheral neuralgia models. Compared with vehicle group, pregabalin significantly increased the resting time and reduced the average speed without resting and distance in locomotor activity test, reduced the time stayed on rotarod in rotarod test. In patch clamp test, compared with vehicle group, camphor significantly reduced the action potential (AP) firing frequency of DRG. Conclusion Camphor can alleviate the symptoms of hyperalgesia in various neuropathic pain models, and has no obvious adverse reactions compared with pregabalin. This effect is related to the down-regulation of DRG neuron excitability.
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Affiliation(s)
- Ziyuan Li
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Yu Gan
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Ting Kang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Yi Zhao
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Tianguang Huang
- Frontiers Science Center for Disease-Related Molecular Network, Sichuan University West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Yuhao Chen
- West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Jin Liu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Bowen Ke
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, Sichuan, People’s Republic of China
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26
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Kim RE, Choi JS. Polysorbate 80 blocked a peripheral sodium channel, Na v1.7, and reduced neuronal excitability. Mol Pain 2023; 19:17448069221150138. [PMID: 36550597 PMCID: PMC9829885 DOI: 10.1177/17448069221150138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Polysorbate 80 is a non-ionic detergent derived from polyethoxylated sorbitan and oleic acid. It is widely used in pharmaceuticals, foods, and cosmetics as an emulsifier. Nav1.7 is a peripheral sodium channel that is highly expressed in sympathetic and sensory neurons, and it plays a critical role in determining the threshold of action potentials (APs). We found that 10 μg/mL polysorbate 80 either abolished APs or increased the threshold of the APs of dorsal root ganglions. We thus investigated whether polysorbate 80 inhibits Nav1.7 sodium current using a whole-cell patch-clamp recording technique. Polysorbate 80 decreased the Nav1.7 current in a concentration-dependent manner with a half-maximal inhibitory concentration (IC50) of 250.4 μg/mL at a holding potential of -120 mV. However, the IC50 was 1.1 μg/mL at a holding potential of -90 mV and was estimated to be 0.9 μg/mL at the resting potentials of neurons, where most channels are inactivated. The activation rate and the voltage dependency of activation of Nav1.7 were not changed by polysorbate 80. However, polysorbate 80 caused hyperpolarizing shifts in the voltage dependency of the steady-state fast inactivation curve. The blocking of Nav1.7 currents by polysorbate 80 was not reversible at a holding potential of -90 mV but was completely reversible at -120 mV, where the channels were mostly in the closed state. Polysorbate 80 also slowed recovery from inactivation and induced robust use-dependent inhibition, indicating that it is likely to bind to and stabilize the inactivated state. Our results indicate that polysorbate 80 inhibits Nav1.7 current in concentration-, state-, and use-dependent manners when used even below commercial concentrations. This suggests that polysorbate 80 may be helpful in pain medicine as an excipient. In addition, in vitro experiments using polysorbate 80 with neurons should be conducted with caution.
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Affiliation(s)
| | - Jin-Sung Choi
- Jin-Sung Choi, Integrated Research Institute of Pharmaceutical Science, College of Pharmacy, The Catholic University of Korea, 43 Jibong-ro, Bucheon-si, Gyeonggi-do 14662, South Korea.
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27
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Ambroxol for neuropathic pain: hiding in plain sight? Pain 2023; 164:3-13. [PMID: 35580314 DOI: 10.1097/j.pain.0000000000002693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/12/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory, antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of respiratory tract diseases and has shown to be efficacious in relieving sore throat. In more recent years, ambroxol has gained interest for its potential usefulness in treating neuropathic pain. Research into this area has been slow, despite clear preclinical evidence to support its primary analgesic mechanism of action-blockade of voltage-gated sodium (Na v ) channels in sensory neurons. Ambroxol is a commercially available inhibitor of Na v 1.8, a crucial player in the pathophysiology of neuropathic pain, and Na v 1.7, a particularly exciting target for the treatment of chronic pain. In this review, we discuss the analgesic mechanisms of action of ambroxol, as well as proposed synergistic properties, followed by the preclinical and clinical results of its use in the treatment of persistent pain and neuropathic pain symptoms, including trigeminal neuralgia, fibromyalgia, and complex regional pain syndrome. With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness, ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for neuropathic pain to market.
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28
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Martinowich K, Das D, Sripathy SR, Mai Y, Kenney RF, Maher BJ. Evaluation of Na v1.8 as a therapeutic target for Pitt Hopkins Syndrome. Mol Psychiatry 2023; 28:76-82. [PMID: 36224259 PMCID: PMC9812766 DOI: 10.1038/s41380-022-01811-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/20/2022] [Indexed: 02/06/2023]
Abstract
Pitt Hopkins Syndrome (PTHS) is a rare syndromic form of autism spectrum disorder (ASD) caused by autosomal dominant mutations in the Transcription Factor 4 (TCF4) gene. TCF4 is a basic helix-loop-helix transcription factor that is critical for neurodevelopment and brain function through its binding to cis-regulatory elements of target genes. One potential therapeutic strategy for PTHS is to identify dysregulated target genes and normalize their dysfunction. Here, we propose that SCN10A is an important target gene of TCF4 that is an applicable therapeutic approach for PTHS. Scn10a encodes the voltage-gated sodium channel Nav1.8 and is consistently shown to be upregulated in PTHS mouse models. In this perspective, we review prior literature and present novel data that suggests inhibiting Nav1.8 in PTHS mouse models is effective at normalizing neuron function, brain circuit activity and behavioral abnormalities and posit this therapeutic approach as a treatment for PTHS.
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Affiliation(s)
- Keri Martinowich
- grid.429552.d0000 0004 5913 1291Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205 USA ,grid.21107.350000 0001 2171 9311Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA ,grid.21107.350000 0001 2171 9311The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
| | - Debamitra Das
- grid.429552.d0000 0004 5913 1291Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205 USA
| | - Srinidhi Rao Sripathy
- grid.429552.d0000 0004 5913 1291Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205 USA
| | - Yishan Mai
- grid.429552.d0000 0004 5913 1291Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205 USA
| | - Rakaia F. Kenney
- grid.429552.d0000 0004 5913 1291Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205 USA
| | - Brady J. Maher
- grid.429552.d0000 0004 5913 1291Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205 USA ,grid.21107.350000 0001 2171 9311Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA ,grid.21107.350000 0001 2171 9311The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205 USA
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29
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Baker CA, Tyagi S, Higerd-Rusli GP, Liu S, Zhao P, Dib-Hajj FB, Waxman SG, Dib-Hajj SD. Paclitaxel effects on axonal localization and vesicular trafficking of Na V1.8. Front Mol Neurosci 2023; 16:1130123. [PMID: 36860665 PMCID: PMC9970094 DOI: 10.3389/fnmol.2023.1130123] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/25/2023] [Indexed: 02/16/2023] Open
Abstract
Patients treated with paclitaxel (PTX) or other antineoplastic agents can experience chemotherapy-induced peripheral neuropathy (CIPN), a debilitating side effect characterized by numbness and pain. PTX interferes with microtubule-based transport, which inhibits tumor growth via cell cycle arrest but can also affect other cellular functions including trafficking of ion channels critical to transduction of stimuli by sensory neurons of the dorsal root ganglia (DRG). We examined the effects of PTX on voltage-gated sodium channel NaV1.8, which is preferentially expressed in DRG neurons, using a microfluidic chamber culture system and chemigenetic labeling to observe anterograde channel transport to the endings of DRG axons in real time. PTX treatment increased the numbers of NaV1.8-containing vesicles traversing the axons. Vesicles in PTX-treated cells exhibited greater average velocity, along with shorter and less frequent pauses along their trajectories. These events were paralleled by greater surface accumulation of NaV1.8 channels at the distal ends of DRG axons. These results were consistent with observations that NaV1.8 is trafficked in the same vesicles containing NaV1.7 channels, which are also involved in pain syndromes in humans and are similarly affected by PTX treatment. However, unlike Nav1.7, we did not detect increased NaV1.8 current density measured at the neuronal soma, suggesting a differential effect of PTX on trafficking of NaV1.8 in soma versus axonal compartments. Therapeutic targeting of axonal vesicular traffic would affect both Nav1.7 and Nav1.8 channels and increase the possibilities of alleviating pain associated with CIPN.
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Affiliation(s)
- Christopher A. Baker
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
| | - Sidharth Tyagi
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
- MD/PhD Program, Yale University, New Haven, CT, United States
| | - Grant P. Higerd-Rusli
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
- MD/PhD Program, Yale University, New Haven, CT, United States
| | - Shujun Liu
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
| | - Peng Zhao
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
| | - Fadia B. Dib-Hajj
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
| | - Stephen G. Waxman
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
- *Correspondence: Stephen G. Waxman, ; Sulayman D. Dib-Hajj,
| | - Sulayman D. Dib-Hajj
- Department of Neurology, Yale University, New Haven, CT, United States
- Center for Neuroscience and Regeneration Research, Yale University, New Haven, CT, United States
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT, United States
- *Correspondence: Stephen G. Waxman, ; Sulayman D. Dib-Hajj,
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30
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Yang H, Shan Z, Guo W, Wang Y, Cai S, Li F, Huang Q, Liu JA, Cheung CW, Cai S. Reversal of Peripheral Neuropathic Pain by the Small-Molecule Natural Product Narirutin via Block of Na v1.7 Voltage-Gated Sodium Channel. Int J Mol Sci 2022; 23:ijms232314842. [PMID: 36499167 PMCID: PMC9738487 DOI: 10.3390/ijms232314842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/12/2022] [Accepted: 11/24/2022] [Indexed: 12/05/2022] Open
Abstract
Neuropathic pain is a refractory chronic disease affecting millions of people worldwide. Given that present painkillers have poor efficacy or severe side effects, developing novel analgesics is badly needed. The multiplex structure of active ingredients isolated from natural products provides a new source for phytochemical compound synthesis. Here, we identified a natural product, Narirutin, a flavonoid compound isolated from the Citrus unshiu, showing antinociceptive effects in rodent models of neuropathic pain. Using calcium imaging, whole-cell electrophysiology, western blotting, and immunofluorescence, we uncovered a molecular target for Narirutin's antinociceptive actions. We found that Narirutin (i) inhibits Veratridine-triggered nociceptor activities in L4-L6 rat dorsal root ganglion (DRG) neurons, (ii) blocks voltage-gated sodium (NaV) channels subtype 1.7 in both small-diameter DRG nociceptive neurons and human embryonic kidney (HEK) 293 cell line, (iii) does not affect tetrodotoxin-resistant (TTX-R) NaV channels, and (iv) blunts the upregulation of Nav1.7 in calcitonin gene-related peptide (CGRP)-labeled DRG sensory neurons after spared nerve injury (SNI) surgery. Identifying Nav1.7 as a molecular target of Narirutin may further clarify the analgesic mechanism of natural flavonoid compounds and provide an optimal idea to produce novel selective and efficient analgesic drugs.
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Affiliation(s)
- Haoyi Yang
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Zhiming Shan
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong 999077, China
- Department of Anesthesiology, Shenzhen People’s Hospital (The First Affiliated Hospital, Southern University of Science and Technology; The Second Clinical Medical College, Jinan University), Shenzhen 518020, China
- Shenzhen Engineering Research Center of Anesthesiology, Shenzhen 518020, China
| | - Weijie Guo
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Yuwei Wang
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Shuxian Cai
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Fuyi Li
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Qiaojie Huang
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
| | - Jessica Aijia Liu
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China
| | - Chi Wai Cheung
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong 999077, China
- Correspondence: (C.W.C.); (S.C.)
| | - Song Cai
- Department of Anatomy and Histology, Shenzhen University Health Science Center, Shenzhen 518060, China
- Correspondence: (C.W.C.); (S.C.)
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Bigsby S, Neapetung J, Campanucci VA. Voltage-gated sodium channels in diabetic sensory neuropathy: Function, modulation, and therapeutic potential. Front Cell Neurosci 2022; 16:994585. [PMID: 36467605 PMCID: PMC9713017 DOI: 10.3389/fncel.2022.994585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/11/2022] [Indexed: 10/29/2023] Open
Abstract
Voltage-gated sodium channels (Na V ) are the main contributors to action potential generation and essential players in establishing neuronal excitability. Na V channels have been widely studied in pain pathologies, including those that develop during diabetes. Diabetic sensory neuropathy (DSN) is one of the most common complications of the disease. DSN is the result of sensory nerve damage by the hyperglycemic state, resulting in a number of debilitating symptoms that have a significant negative impact in the quality of life of diabetic patients. Among those symptoms are tingling and numbness of hands and feet, as well as exacerbated pain responses to noxious and non-noxious stimuli. DSN is also a major contributor to the development of diabetic foot, which may lead to lower limb amputations in long-term diabetic patients. Unfortunately, current treatments fail to reverse or successfully manage DSN. In the current review we provide an updated report on Na V channels including structure/function and contribution to DSN. Furthermore, we summarize current research on the therapeutic potential of targeting Na V channels in pain pathologies, including DSN.
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Affiliation(s)
| | | | - Verónica A. Campanucci
- Department of Anatomy, Physiology and Pharmacology (APP), College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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32
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Shen Y, Zheng Y, Hong D. Familial Episodic Pain Syndromes. J Pain Res 2022; 15:2505-2515. [PMID: 36051609 PMCID: PMC9427007 DOI: 10.2147/jpr.s375299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/26/2022] [Indexed: 11/23/2022] Open
Abstract
Over the past decades, advances in genetic sequencing have opened a new world of discovery of causative genes associated with numerous pain-related syndromes. Familial episodic pain syndromes (FEPS) are one of the distinctive syndromes characterized by early-childhood onset of severe episodic pain mainly affecting the distal extremities and tend to attenuate or diminish with age. According to the phenotypic and genetic properties, FEPS at least includes four subtypes of FEPS1, FEPS2, FEPS3, and FEPS4, which are caused by mutations in the TRPA1, SCN10A, SCN11A, and SCN9A genes, respectively. Functional studies have revealed that all missense mutations in these genes are closely associated with the gain-of-function of cation channels. Because some FEPS patients may show a relative treatability and favorable prognosis, it is worth paying attention to the diagnosis and management of FEPS as early as possible. In this review, we state the common clinical manifestations, pathogenic mechanisms, and potential therapies of the disease, and provide preliminary opinions about future research for FEPS.
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Affiliation(s)
- Yu Shen
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China
| | - Yilei Zheng
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China
| | - Daojun Hong
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China.,Department of Medical Genetics, The First Affiliated Hospital of Nanchang University, Nanchang, 330006, People's Republic of China
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33
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Contribution of tetrodotoxin-resistant persistent Na + currents to the excitability of C-type dural afferent neurons in rats. J Headache Pain 2022; 23:73. [PMID: 35764917 PMCID: PMC9238149 DOI: 10.1186/s10194-022-01443-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/20/2022] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Growing evidence supports the important role of persistent sodium currents (INaP) in the neuronal excitability of various central neurons. However, the role of tetrodotoxin-resistant (TTX-R) Na+ channel-mediated INaP in the neuronal excitability of nociceptive neurons remains poorly understood. METHODS We investigated the functional role of TTX-R INaP in the excitability of C-type nociceptive dural afferent neurons, which was identified using a fluorescent dye, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchloride (DiI), and a whole-cell patch-clamp technique. RESULTS TTX-R INaP were found in most DiI-positive neurons, but their density was proportional to neuronal size. Although the voltage dependence of TTX-R Na+ channels did not differ among DiI-positive neurons, the extent of the onset of slow inactivation, recovery from inactivation, and use-dependent inhibition of these channels was highly correlated with neuronal size and, to a great extent, the density of TTX-R INaP. In the presence of TTX, treatment with a specific INaP inhibitor, riluzole, substantially decreased the number of action potentials generated by depolarizing current injection, suggesting that TTX-R INaP are related to the excitability of dural afferent neurons. In animals treated chronically with inflammatory mediators, the density of TTX-R INaP was significantly increased, and it was difficult to inactivate TTX-R Na+ channels. CONCLUSIONS TTX-R INaP apparently contributes to the differential properties of TTX-R Na+ channels and neuronal excitability. Consequently, the selective modulation of TTX-R INaP could be, at least in part, a new approach for the treatment of migraine headaches.
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George K, Lopez-Mateos D, Abd El-Aziz TM, Xiao Y, Kline J, Bao H, Raza S, Stockand JD, Cummins TR, Fornelli L, Rowe MP, Yarov-Yarovoy V, Rowe AH. Structural and Functional Characterization of a Novel Scorpion Toxin that Inhibits NaV1.8 via Interactions With the DI Voltage Sensor and DII Pore Module. Front Pharmacol 2022; 13:846992. [PMID: 35662692 PMCID: PMC9160825 DOI: 10.3389/fphar.2022.846992] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/05/2022] [Indexed: 11/30/2022] Open
Abstract
Voltage-gated sodium channel NaV1.8 regulates transmission of pain signals to the brain. While NaV1.8 has the potential to serve as a drug target, the molecular mechanisms that shape NaV1.8 gating are not completely understood, particularly mechanisms that couple activation to inactivation. Interactions between toxin producing animals and their predators provide a novel approach for investigating NaV structure-function relationships. Arizona bark scorpions produce Na+ channel toxins that initiate pain signaling. However, in predatory grasshopper mice, toxins inhibit NaV1.8 currents and block pain signals. A screen of synthetic peptide toxins predicted from bark scorpion venom showed that peptide NaTx36 inhibited Na+ current recorded from a recombinant grasshopper mouse NaV1.8 channel (OtNaV1.8). Toxin NaTx36 hyperpolarized OtNaV1.8 activation, steady-state fast inactivation, and slow inactivation. Mutagenesis revealed that the first gating charge in the domain I (DI) S4 voltage sensor and an acidic amino acid (E) in the DII SS2 – S6 pore loop are critical for the inhibitory effects of NaTx36. Computational modeling showed that a DI S1 – S2 asparagine (N) stabilizes the NaTx36 – OtNaV1.8 complex while residues in the DI S3 – S4 linker and S4 voltage sensor form electrostatic interactions that allow a toxin glutamine (Q) to contact the first S4 gating charge. Surprisingly, the models predicted that NaTx36 contacts amino acids in the DII S5 – SS1 pore loop instead of the SS2 – S6 loop; the DII SS2 – S6 loop motif (QVSE) alters the conformation of the DII S5 – SS1 pore loop, enhancing allosteric interactions between toxin and the DII S5 – SS1 pore loop. Few toxins have been identified that modify NaV1.8 gating. Moreover, few toxins have been described that modify sodium channel gating via the DI S4 voltage sensor. Thus, NaTx36 and OtNaV1.8 provide tools for investigating the structure-activity relationship between channel activation and inactivation gating, and the connection to alternative pain phenotypes.
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Affiliation(s)
- Kiran George
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Diego Lopez-Mateos
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
| | - Tarek Mohamed Abd El-Aziz
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, TX, United States
- Zoology Department, Faculty of Science, Minia University, El-Minia, Egypt
- Amsaal Venom Farm L.L.C., Abu Dhabi, United Arab Emirates
| | - Yucheng Xiao
- Department of Biology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Jake Kline
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Hong Bao
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Syed Raza
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - James D. Stockand
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, TX, United States
| | - Theodore R. Cummins
- Department of Biology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Luca Fornelli
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Matthew P. Rowe
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA, United States
- Biophysics Graduate Group, University of California, Davis, Davis, CA, United States
- Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, CA, United States
| | - Ashlee H. Rowe
- Department of Biology, University of Oklahoma, Norman, OK, United States
- Graduate Program in Cellular and Behavioral Neurobiology, University of Oklahoma, Norman, OK, United States
- *Correspondence: Ashlee H. Rowe,
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35
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Yang R, Song Y, Wang H, Chen C, Bai F, Li C. BmK DKK13, A Scorpion Toxin, Alleviates Pain Behavior in a Rat Model of Trigeminal Neuralgia by Modulating Voltage-Gated Sodium Channels and MAPKs/CREB Pathway. Mol Neurobiol 2022; 59:4535-4549. [PMID: 35579847 DOI: 10.1007/s12035-022-02855-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 04/27/2022] [Indexed: 12/01/2022]
Abstract
BmK DKK13 (DKK13) is a mutated recombinant peptide, which has a significant antinociception in a rat model of the inflammatory pain. The purpose of this study was to evaluate the antinociceptive effect of DKK13 on trigeminal neuralgia (TN) in rats. Male Sprague-Dawley (SD) rats were treated with the chronic constriction injury of the infraorbital nerve (IoN-CCI) model to induce stable symptoms of TN. DKK13 (1.0 mg/kg, 2.0 mg/kg and 4.0 mg/kg, i.v.) or morphine (4.0 mg/kg, i.v.) was administered by tail vein once on day 14 after IoN-CCI injury. Behavioral tests, electrophysiology and western blotting were performed to investigate the role and underlying mechanisms of DKK13 on IoN-CCI model. Behavioral test results showed that DKK13 could significantly increase the mechanical pain and thermal radiation pain thresholds of IoN-CCI rats and inhibit the asymmetric spontaneous pain scratching behavior. Electrophysiological results showed that DKK13 could significantly reduce the current density of Nav1.8 in the ipsilateral side of trigeminal ganglion (TG) neurons in IoN-CCI rats, and the steady-state activation and inactivation curves of Nav1.8 shifted, respectively, to the direction of hyperpolarization and depolarization. Western blotting results showed that DKK13 significantly reduced the expression of Nav1.8 and the phosphorylation levels of key proteins of MAPKs/CREB pathway in TG tissues of IoN-CCI rats. In brief, DKK13 has a significant antinociceptive effect on IoN-CCI rats, which may be achieved by changing the dynamic characteristics of Nav1.8 channel and regulating the protein phosphorylation in MAPKs/CREB pathway.
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Affiliation(s)
- Ran Yang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Yongbo Song
- School of Life Sciences and Biopharmaceutical Science, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Haipeng Wang
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Chunyun Chen
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Fei Bai
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Chunli Li
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang, 110016, China.
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36
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Multitarget nociceptor sensitization by a promiscuous peptide from the venom of the King Baboon spider. Proc Natl Acad Sci U S A 2022; 119:2110932119. [PMID: 35074873 PMCID: PMC8812547 DOI: 10.1073/pnas.2110932119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2021] [Indexed: 12/15/2022] Open
Abstract
The King Baboon spider, Pelinobius muticus, is a burrowing African tarantula. Its impressive size and appealing coloration are tempered by reports describing severe localized pain, swelling, itchiness, and muscle cramping after accidental envenomation. Hyperalgesia is the most prominent symptom after bites from P. muticus, but the molecular basis by which the venom induces pain is unknown. Proteotranscriptomic analysis of P. muticus venom uncovered a cysteine-rich peptide, δ/κ-theraphotoxin-Pm1a (δ/κ-TRTX-Pm1a), that elicited nocifensive behavior when injected into mice. In small dorsal root ganglion neurons, synthetic δ/κ-TRTX-Pm1a (sPm1a) induced hyperexcitability by enhancing tetrodotoxin-resistant sodium currents, impairing repolarization and lowering the threshold of action potential firing, consistent with the severe pain associated with envenomation. The molecular mechanism of nociceptor sensitization by sPm1a involves multimodal actions over several ion channel targets, including NaV1.8, KV2.1, and tetrodotoxin-sensitive NaV channels. The promiscuous targeting of peptides like δ/κ-TRTX-Pm1a may be an evolutionary adaptation in pain-inducing defensive venoms.
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37
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Alsaloum M, Waxman SG. iPSCs and DRGs: stepping stones to new pain therapies. Trends Mol Med 2022; 28:110-122. [PMID: 34933815 PMCID: PMC8810720 DOI: 10.1016/j.molmed.2021.11.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 02/03/2023]
Abstract
There is a pressing need for more effective nonaddictive treatment options for pain. Pain signals are transmitted from the periphery into the spinal cord via dorsal root ganglion (DRG) neurons, whose excitability is driven by voltage-gated sodium (NaV) channels. Three NaV channels (NaV1.7, NaV1.8, and NaV1.9), preferentially expressed in DRG neurons, play important roles in pain signaling in humans. Blockade of these channels may provide a novel approach to the treatment of pain, but clinical translation of preclinical results has been challenging, in part due to differences between rodent and human DRG neurons. Human DRG neurons and iPSC-derived sensory neurons (iPSC-SNs) provide new preclinical platforms that may facilitate the development of novel pain therapeutics.
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Affiliation(s)
- Matthew Alsaloum
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA; Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA; Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA; Yale Medical Scientist Training Program, Yale School of Medicine, New Haven, CT, USA; Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA; Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA; Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA.
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38
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Villalba‐Riquelme E, de la Torre‐Martínez R, Fernández‐Carvajal A, Ferrer‐Montiel A. Paclitaxel in vitro reversibly sensitizes the excitability of IB4(-) and IB4(+) sensory neurons from male and female rats. Br J Pharmacol 2022; 179:3693-3710. [PMID: 35102580 PMCID: PMC9311666 DOI: 10.1111/bph.15809] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 01/03/2022] [Accepted: 01/23/2022] [Indexed: 11/27/2022] Open
Affiliation(s)
- Eva Villalba‐Riquelme
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE)Universitas Miguel HernándezElcheSpain
| | | | - Asia Fernández‐Carvajal
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE)Universitas Miguel HernándezElcheSpain
| | - Antonio Ferrer‐Montiel
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE)Universitas Miguel HernándezElcheSpain
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39
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Deuis JR, Ragnarsson L, Robinson SD, Dekan Z, Chan L, Jin AH, Tran P, McMahon KL, Li S, Wood JN, Cox JJ, King GF, Herzig V, Vetter I. The Tarantula Venom Peptide Eo1a Binds to the Domain II S3-S4 Extracellular Loop of Voltage-Gated Sodium Channel Na V1.8 to Enhance Activation. Front Pharmacol 2022; 12:789570. [PMID: 35095499 PMCID: PMC8795738 DOI: 10.3389/fphar.2021.789570] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/20/2021] [Indexed: 12/19/2022] Open
Abstract
Venoms from cone snails and arachnids are a rich source of peptide modulators of voltage-gated sodium (NaV) channels, however relatively few venom-derived peptides with activity at the mammalian NaV1.8 subtype have been isolated. Here, we describe the discovery and functional characterisation of β-theraphotoxin-Eo1a, a peptide from the venom of the Tanzanian black and olive baboon tarantula Encyocratella olivacea that modulates NaV1.8. Eo1a is a 37-residue peptide that increases NaV1.8 peak current (EC50 894 ± 146 nM) and causes a large hyperpolarising shift in both the voltage-dependence of activation (ΔV50-20.5 ± 1.2 mV) and steady-state fast inactivation (ΔV50-15.5 ± 1.8 mV). At a concentration of 10 μM, Eo1a has varying effects on the peak current and channel gating of NaV1.1-NaV1.7, although its activity is most pronounced at NaV1.8. Investigations into the binding site of Eo1a using NaV1.7/NaV1.8 chimeras revealed a critical contribution of the DII S3-S4 extracellular loop of NaV1.8 to toxin activity. Results from this work may form the basis for future studies that lead to the rational design of spider venom-derived peptides with improved potency and selectivity at NaV1.8.
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Affiliation(s)
- Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Lotten Ragnarsson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Samuel D. Robinson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Zoltan Dekan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Lerena Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Ai-Hua Jin
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Poanna Tran
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Kirsten L. McMahon
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Shengnan Li
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - John N. Wood
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - James J. Cox
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia
| | - Volker Herzig
- GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD, Australia
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40
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Wang X, Zhang B, Li X, Liu X, Wang S, Xie Y, Pi J, Yang Z, Li J, Jia Q, Zhang Y. Mechanisms Underlying Gastrodin Alleviating Vincristine-Induced Peripheral Neuropathic Pain. Front Pharmacol 2022; 12:744663. [PMID: 34975470 PMCID: PMC8716817 DOI: 10.3389/fphar.2021.744663] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 11/30/2021] [Indexed: 12/16/2022] Open
Abstract
Gastrodin (GAS) is the main bioactive ingredient of Gastrodia, a famous Chinese herbal medicine widely used as an analgesic, but the underlying analgesic mechanism is still unclear. In this study, we first observed the effects of GAS on the vincristine-induced peripheral neuropathic pain by alleviating the mechanical and thermal hyperalgesia. Further studies showed that GAS could inhibit the current density of NaV1.7 and NaV1.8 channels and accelerate the inactivation process of NaV1.7 and NaV1.8 channel, thereby inhibiting the hyperexcitability of neurons. Additionally, GAS could significantly reduce the over-expression of NaV1.7 and NaV1.8 on DRG neurons from vincristine-treated rats according to the analysis of Western blot and immunofluorescence results. Moreover, based on the molecular docking and molecular dynamic simulation, the binding free energies of the constructed systems were calculated, and the binding sites of GAS on the sodium channels (NaV1.7 and NaV1.8) were preliminarily determined. This study has shown that modulation of NaV1.7 and NaV1.8 sodium channels by GAS contributing to the alleviation of vincristine-induced peripheral neuropathic pain, thus expanding the understanding of complex action of GAS as a neuromodulator.
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Affiliation(s)
- Xiangyu Wang
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Boxuan Zhang
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Xuedong Li
- School of Pharmacy, Hebei Medical University, Shijiazhuang, China.,Laboratory of Neural and Vascular Biology of Ministry of Education, Hebei Medical University, Shijiazhuang, China
| | - Xingang Liu
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Songsong Wang
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Yuan Xie
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Jialing Pi
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Zhiyuan Yang
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Jincan Li
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Qingzhong Jia
- Departments of Pharmacology, Hebei Medical University, Shijiazhuang, China.,School of Pharmacy, Hebei Medical University, Shijiazhuang, China.,Key Laboratory of Innovative Drug Research and Evaluation of Hebei Province, Shijiazhuang, China.,Laboratory of Neural and Vascular Biology of Ministry of Education, Hebei Medical University, Shijiazhuang, China
| | - Yang Zhang
- School of Pharmacy, Hebei Medical University, Shijiazhuang, China.,Laboratory of Neural and Vascular Biology of Ministry of Education, Hebei Medical University, Shijiazhuang, China
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Velasco E, Alvarez JL, Meseguer VM, Gallar J, Talavera K. Membrane potential instabilities in sensory neurons: mechanisms and pathophysiological relevance. Pain 2022; 163:64-74. [PMID: 34086629 DOI: 10.1097/j.pain.0000000000002289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/29/2021] [Indexed: 11/25/2022]
Abstract
ABSTRACT Peripheral sensory neurons transduce physicochemical stimuli affecting somatic tissues into the firing of action potentials that are conveyed to the central nervous system. This results in conscious perception, adaptation, and survival, but alterations of the firing patterns can result in pain and hypersensitivity conditions. Thus, understanding the molecular mechanisms underlying action potential firing in peripheral sensory neurons is essential in sensory biology and pathophysiology. Over the past 30 years, it has been consistently reported that these cells can display membrane potential instabilities (MPIs), in the form of subthreshold membrane potential oscillations or depolarizing spontaneous fluctuations. However, research on this subject remains sparse, without a clear conductive thread to be followed. To address this, we here provide a synthesis of the description, molecular bases, mathematical models, physiological roles, and pathophysiological implications of MPIs in peripheral sensory neurons. Membrane potential instabilities have been reported in trigeminal, dorsal root, and Mes-V ganglia, where they are believed to support repetitive firing. They are proposed to have roles also in intercellular communication, ectopic firing, and responses to tonic and slow natural stimuli. We highlight how MPIs are of great interest for the study of sensory transduction physiology and how they may represent therapeutic targets for many pathological conditions, such as acute and chronic pain, itch, and altered sensory perceptions. We identify future research directions, including the elucidation of the underlying molecular determinants and modulation mechanisms, their relation to the encoding of natural stimuli and their implication in pain and hypersensitivity conditions.
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Affiliation(s)
- Enrique Velasco
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Julio L Alvarez
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, VIB Center for Brain & Disease Research, Leuven, Belgium
| | - Victor M Meseguer
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante, San Juan de Alicante, Spain
| | - Karel Talavera
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, VIB Center for Brain & Disease Research, Leuven, Belgium
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Contributions of Na V1.8 and Na V1.9 to excitability in human induced pluripotent stem-cell derived somatosensory neurons. Sci Rep 2021; 11:24283. [PMID: 34930944 PMCID: PMC8688473 DOI: 10.1038/s41598-021-03608-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 12/02/2021] [Indexed: 12/13/2022] Open
Abstract
The inhibition of voltage-gated sodium (NaV) channels in somatosensory neurons presents a promising novel modality for the treatment of pain. However, the precise contribution of these channels to neuronal excitability, the cellular correlate of pain, is unknown; previous studies using genetic knockout models or pharmacologic block of NaV channels have identified general roles for distinct sodium channel isoforms, but have never quantified their exact contributions to these processes. To address this deficit, we have utilized dynamic clamp electrophysiology to precisely tune in varying levels of NaV1.8 and NaV1.9 currents into induced pluripotent stem cell-derived sensory neurons (iPSC-SNs), allowing us to quantify how graded changes in these currents affect different parameters of neuronal excitability and electrogenesis. We quantify and report direct relationships between NaV1.8 current density and action potential half-width, overshoot, and repetitive firing. We additionally quantify the effect varying NaV1.9 current densities have on neuronal membrane potential and rheobase. Furthermore, we examined the simultaneous interplay between NaV1.8 and NaV1.9 on neuronal excitability. Finally, we show that minor biophysical changes in the gating of NaV1.8 can render human iPSC-SNs hyperexcitable, in a first-of-its-kind investigation of a gain-of-function NaV1.8 mutation in a human neuronal background.
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Kim G, Nakamura M, Cho JH, Nam S, Jang IS. Sevoflurane modulation of tetrodotoxin-resistant Na+ channels in small-sized dorsal root ganglion neurons of rats. Neuroreport 2021; 32:1335-1340. [PMID: 34718245 DOI: 10.1097/wnr.0000000000001731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Volatile anesthetics are widely used for general anesthesia during surgical operations. Voltage-gated Na+ channels expressed in central neurons are major targets for volatile anesthetics; but it is unclear whether these drugs modulate native tetrodotoxin-resistant (TTX-R) Na+ channels, which are involved in the development and maintenance of inflammatory pain. METHODS In this study, we examined the effects of sevoflurane on TTX-R Na+ currents (INa) in acutely isolated rat dorsal root ganglion neurons, using a whole-cell patch-clamp technique. RESULTS Sevoflurane slightly potentiated the peak amplitude of transient TTX-R INa but more potently inhibited slow voltage-ramp-induced persistent INa in a concentration-dependent manner. Sevoflurane (0.86 ± 0.02 mM) (1) slightly shifted the steady-state fast inactivation relationship to hyperpolarizing ranges without affecting the voltage-activation relationship, (2) reduced the extent of use-dependent inhibition of Na+ channels, (3) accelerated the onset of inactivation and (4) delayed the recovery from inactivation of TTX-R Na+ channels. Thus, sevoflurane has diverse effects on TTX-R Na+ channels expressed in nociceptive neurons. CONCLUSIONS The present results suggest that the inhibition of persistent INa and the modulation of the voltage dependence and inactivation might be, at least in part, responsible for the analgesic effects elicited by sevoflurane.
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Affiliation(s)
| | - Michiko Nakamura
- Department of Pharmacology, School of Dentistry
- Brain Science & Engineering Institute, Kyungpook National University, Daegu, Republic of Korea
| | | | | | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry
- Brain Science & Engineering Institute, Kyungpook National University, Daegu, Republic of Korea
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Szulczyk B, Pasierski M, Gawlak M. Prefrontal cortex pyramidal neurons express functional Nav1.8 tetrodotoxin-resistant sodium currents. Clin Exp Pharmacol Physiol 2021; 49:350-359. [PMID: 34750860 DOI: 10.1111/1440-1681.13610] [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: 08/12/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 11/27/2022]
Abstract
It has been repeatedly proved that Nav1.8 tetrodotoxin (TTX)-resistant sodium currents are expressed in peripheral sensory neurons where they play important role in nociception. There are very few publications that show the presence of TTX-resistant sodium currents in central neurons. The aim of this study was to assess if functional Nav1.8 TTX-resistant sodium currents are expressed in prefrontal cortex pyramidal neurons. All recordings were performed in the presence of TTX in the extracellular solution to block TTX-sensitive sodium currents. The TTX-resistant sodium current recorded in this study was mainly carried by the Nav1.8 sodium channel isoform because the Nav1.9 current was inhibited by the -65 mV holding potential that we used throughout the study. Moreover, the sodium current that we recorded was inhibited by treatment with the selective Nav1.8 inhibitor A-803467. Confocal microscopy experiments confirmed the presence of the Nav1.8 α subunit in prefrontal cortex pyramidal neurons. Activation and steady state inactivation properties of TTX-resistant sodium currents were also assessed in this study and they were similar to activation and inactivation properties of TTX-resistant sodium currents expressed in dorsal root ganglia (DRG) neurons. Moreover, this study showed that carbamazepine (60 µM) inhibited the maximal amplitude of the TTX-resistant sodium current. Furthermore, we found that carbamazepine shifts steady state inactivation curve of TTX-resistant sodium currents toward hyperpolarization. This study suggests that the Nav1.8 TTX-resistant sodium channel is expressed not only in DRG neurons, but also in cortical neurons and may be molecular target for antiepileptic drugs such as carbamazepine.
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Affiliation(s)
- Bartłomiej Szulczyk
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Poland
| | - Michał Pasierski
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Poland
| | - Maciej Gawlak
- Department of Pharmacodynamics, The Medical University of Warsaw, Warsaw, Poland
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Nakamura M, Jang IS. Propranolol modulation of tetrodotoxin-resistant Na + channels in dural afferent neurons. Eur J Pharmacol 2021; 910:174449. [PMID: 34454925 DOI: 10.1016/j.ejphar.2021.174449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
Propranolol, a representative adrenergic β-receptor antagonist, is widely used to prevent migraine attacks. Although propranolol is well known to inhibit tetrodotoxin-resistant (TTX-R) Na+ channels in cardiac myocytes, it is unclear whether the drug modulates these channels expressed in dural afferent neurons. In this study, we examined the effects of propranolol on TTX-R Na+ channels in medium-sized dural afferent neurons identified by the fluorescent dye DiI. The TTX-R Na+ currents (INa) were recorded from acutely isolated DiI-positive neurons using a whole-cell patch clamp technique under voltage-clamp conditions. Propranolol inhibited the noninactivating steady-state component more potently than the peak component of transient TTX-R INa. Propranolol also potently inhibited the slow voltage ramp-induced TTX-R INa in a concentration-dependent manner, suggesting that it preferentially inhibited the noninactivating or persistent INa in DiI-positive neurons. Propranolol had little effect on voltage dependence, but it increased the extent of the use-dependent inhibition of TTX-R Na+ channels. Propranolol also accelerated the onset of inactivation and retarded recovery from inactivation in these channels. Under current-clamp conditions, propranolol decreased the number of action potentials elicited by depolarizing current stimuli. In conclusion, the propranolol-mediated preferential inhibition of persistent INa and modulation of the inactivation kinetics of TTX-R Na+ channels might represent additional mechanisms for migraine prophylaxis.
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Affiliation(s)
- Michiko Nakamura
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu, 41940, Republic of Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu, 41940, Republic of Korea.
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The insecticide deltamethrin enhances sodium channel slow inactivation of human Nav1.9, Nav1.8 and Nav1.7. Toxicol Appl Pharmacol 2021; 428:115676. [PMID: 34389319 DOI: 10.1016/j.taap.2021.115676] [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: 05/05/2021] [Revised: 07/13/2021] [Accepted: 08/08/2021] [Indexed: 01/05/2023]
Abstract
The insecticide deltamethrin of the pyrethroid class mainly targets voltage-gated sodium channels (Navs). Deltamethrin prolongs the opening of Navs by slowing down fast inactivation and deactivation. Pyrethroids are supposedly safe for humans, however, they have also been linked to the gulf-war syndrome, a neuropathic pain condition that can develop following exposure to certain chemicals. Inherited neuropathic pain conditions have been linked to mutations in the Nav subtypes Nav1.7, Nav1.8, and Nav1.9. Here, we examined the effect of deltamethrin on the human isoforms Nav1.7, Nav1.8, and Nav1.9_C4 (chimera containing the C-terminus of rat Nav1.4) heterologously expressed in HEK293T and ND7/23 cells using whole-cell patch-clamp electrophysiology. For all three Nav subtypes, we observed increased persistent and tail currents that are typical for Nav channels modified by deltamethrin. The most surprising finding was an enhanced slow inactivation induced by deltamethrin in all three Nav subtypes. An enhanced slow inactivation is contrary to the prolonged opening caused by pyrethroids and has not been described for deltamethrin or any other pyrethroid before. Furthermore, we found that the fraction of deltamethrin-modified channels increased use-dependently. However, for Nav1.8, the use-dependent potentiation occurred only when the holding potential was increased to -90 mV, a potential at which the tail currents decay more slowly. This indicates that use-dependent modification is due to an accumulation of tail currents. In summary, our findings support a novel mechanism whereby deltamethrin enhances slow inactivation of voltage-gated sodium channels, which may, depending on the cellular resting membrane potential, reduce neuronal excitability and counteract the well-described pyrethroid effects of prolonging channel opening.
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Heinrichs B, Liu B, Zhang J, Meents JE, Le K, Erickson A, Hautvast P, Zhu X, Li N, Liu Y, Spehr M, Habel U, Rothermel M, Namer B, Zhang X, Lampert A, Duan G. The Potential Effect of Na v 1.8 in Autism Spectrum Disorder: Evidence From a Congenital Case With Compound Heterozygous SCN10A Mutations. Front Mol Neurosci 2021; 14:709228. [PMID: 34385907 PMCID: PMC8354588 DOI: 10.3389/fnmol.2021.709228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/07/2021] [Indexed: 12/17/2022] Open
Abstract
Apart from the most prominent symptoms in Autism spectrum disorder (ASD), namely deficits in social interaction, communication and repetitive behavior, patients often show abnormal sensory reactivity to environmental stimuli. Especially potentially painful stimuli are reported to be experienced in a different way compared to healthy persons. In our present study, we identified an ASD patient carrying compound heterozygous mutations in the voltage-gated sodium channel (VGSC) Na v 1.8, which is preferentially expressed in sensory neurons. We expressed both mutations, p.I1511M and p.R512∗, in a heterologous expression system and investigated their biophysical properties using patch-clamp recordings. The results of these experiments reveal that the p.R512∗ mutation renders the channel non-functional, while the p.I1511M mutation showed only minor effects on the channel's function. Behavioral experiments in a Na v 1.8 loss-of-function mouse model additionally revealed that Na v 1.8 may play a role in autism-like symptomatology. Our results present Na v 1.8 as a protein potentially involved in ASD pathophysiology and may therefore offer new insights into the genetic basis of this disease.
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Affiliation(s)
- Björn Heinrichs
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Baowen Liu
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jin Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jannis E. Meents
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Kim Le
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Andelain Erickson
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Petra Hautvast
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Xiwen Zhu
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Ningbo Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Liu
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, Uniklinik RWTH Aachen University, Aachen, Germany
- JARA-BRAIN Institute Brain Structure-Function Relationships: Decoding the Human Brain at Systemic Levels, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Markus Rothermel
- Institute for Physiology and Cell Biology, University of Veterinary Medicine, Foundation, Hanover, Germany
| | - Barbara Namer
- Research Group Neurosciences of the Interdisciplinary Center for Clinical Research (IZKF), Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Xianwei Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Angelika Lampert
- Institute of Physiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Guangyou Duan
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
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Abd El-Aziz TM, Xiao Y, Kline J, Gridley H, Heaston A, Linse KD, Ward MJ, Rokyta DR, Stockand JD, Cummins TR, Fornelli L, Rowe AH. Identification and Characterization of Novel Proteins from Arizona Bark Scorpion Venom That Inhibit Nav1.8, a Voltage-Gated Sodium Channel Regulator of Pain Signaling. Toxins (Basel) 2021; 13:toxins13070501. [PMID: 34357973 PMCID: PMC8310189 DOI: 10.3390/toxins13070501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022] Open
Abstract
The voltage-gated sodium channel Nav1.8 is linked to neuropathic and inflammatory pain, highlighting the potential to serve as a drug target. However, the biophysical mechanisms that regulate Nav1.8 activation and inactivation gating are not completely understood. Progress has been hindered by a lack of biochemical tools for examining Nav1.8 gating mechanisms. Arizona bark scorpion (Centruroides sculpturatus) venom proteins inhibit Nav1.8 and block pain in grasshopper mice (Onychomys torridus). These proteins provide tools for examining Nav1.8 structure–activity relationships. To identify proteins that inhibit Nav1.8 activity, venom samples were fractioned using liquid chromatography (reversed-phase and ion exchange). A recombinant Nav1.8 clone expressed in ND7/23 cells was used to identify subfractions that inhibited Nav1.8 Na+ current. Mass-spectrometry-based bottom-up proteomic analyses identified unique peptides from inhibitory subfractions. A search of the peptides against the AZ bark scorpion venom gland transcriptome revealed four novel proteins between 40 and 60% conserved with venom proteins from scorpions in four genera (Centruroides, Parabuthus, Androctonus, and Tityus). Ranging from 63 to 82 amino acids, each primary structure includes eight cysteines and a “CXCE” motif, where X = an aromatic residue (tryptophan, tyrosine, or phenylalanine). Electrophysiology data demonstrated that the inhibitory effects of bioactive subfractions can be removed by hyperpolarizing the channels, suggesting that proteins may function as gating modifiers as opposed to pore blockers.
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Affiliation(s)
- Tarek Mohamed Abd El-Aziz
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (T.M.A.E.-A.); (J.D.S.)
- Zoology Department, Faculty of Science, Minia University, El-Minia 61519, Egypt
| | - Yucheng Xiao
- Department of Biology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (Y.X.); (T.R.C.)
| | - Jake Kline
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA; (J.K.); (H.G.); (A.H.); (L.F.)
| | - Harold Gridley
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA; (J.K.); (H.G.); (A.H.); (L.F.)
| | - Alyse Heaston
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA; (J.K.); (H.G.); (A.H.); (L.F.)
| | - Klaus D. Linse
- Bio-Synthesis Inc., 612 E. Main Street, Lewisville, TX 75057, USA;
| | - Micaiah J. Ward
- Department of Biological Sciences, Florida State University, 319 Stadium Drive, Tallahassee, FL 32306, USA; (M.J.W.); (D.R.R.)
| | - Darin R. Rokyta
- Department of Biological Sciences, Florida State University, 319 Stadium Drive, Tallahassee, FL 32306, USA; (M.J.W.); (D.R.R.)
| | - James D. Stockand
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (T.M.A.E.-A.); (J.D.S.)
| | - Theodore R. Cummins
- Department of Biology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA; (Y.X.); (T.R.C.)
| | - Luca Fornelli
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA; (J.K.); (H.G.); (A.H.); (L.F.)
| | - Ashlee H. Rowe
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA; (J.K.); (H.G.); (A.H.); (L.F.)
- Correspondence: ; Tel.: +1-936-577-5782
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The Changes in Expression of Na V1.7 and Na V1.8 and the Effects of the Inhalation of Their Blockers in Healthy and Ovalbumin-Sensitized Guinea Pig Airways. MEMBRANES 2021; 11:membranes11070511. [PMID: 34357161 PMCID: PMC8304019 DOI: 10.3390/membranes11070511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 01/06/2023]
Abstract
Background: The presented study evaluated the suppositional changes in the airway expression of Nav1.8 and Nav1.7 and their role in the airway defense mechanisms in healthy animals and in an experimental asthma model. Methods: The effects of the blockers inhalation on the reactivity of guinea pig airways, number of citric-acid-induced coughs and ciliary beating frequency (CBF) were tested in vivo. Chronic inflammation simulating asthma was induced by repetitive exposure to ovalbumin. The expression of Nav1.7 and Nav1.8 was examined by ELISA. Results: The Nav 1.8 blocker showed complex antitussive and bronchodilatory effects and significantly regulated the CBF in healthy and sensitized animals. The Nav1.7 blockers significantly inhibited coughing and participated in CBF control in the ovalbumin-sensitized animals. The increased expression of the respective ion channels in the sensitized animals corresponded to changes in CBF regulation. The therapeutic potency of the Nav1.8 blocker was evidenced in combinations with classic bronchodilators. Conclusion: The allergic-inflammation-upregulated expression of Nav1.7 and Nav1.8 and corresponding effects of blocker inhalation on airway defense mechanisms, along with the Nav1.8 blocker’s compatibility with classic antiasthmatic drugs, bring novel possibilities for the treatment of various respiratory diseases. However, the influence of the Nav1.8 blocker on CBF requires further investigation.
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Cannabidiol Inhibition of Murine Primary Nociceptors: Tight Binding to Slow Inactivated States of Na v1.8 Channels. J Neurosci 2021; 41:6371-6387. [PMID: 34131037 DOI: 10.1523/jneurosci.3216-20.2021] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 05/11/2021] [Accepted: 06/04/2021] [Indexed: 02/06/2023] Open
Abstract
The nonpsychoactive phytocannabinoid cannabidiol (CBD) has been shown to have analgesic effects in animal studies but little is known about its mechanism of action. We examined the effects of CBD on intrinsic excitability of primary pain-sensing neurons. Studying acutely dissociated capsaicin-sensitive mouse DRG neurons at 37°C, we found that CBD effectively inhibited repetitive action potential firing, from 15-20 action potentials evoked by 1 s current injections in control to 1-3 action potentials with 2 μm CBD. Reduction of repetitive firing was accompanied by a reduction of action potential height, widening of action potentials, reduction of the afterhyperpolarization, and increased propensity to enter depolarization block. Voltage-clamp experiments showed that CBD inhibited both TTX-sensitive and TTX-resistant (TTX-R) sodium currents in a use-dependent manner. CBD showed strong state-dependent inhibition of TTX-R channels, with fast binding to inactivated channels during depolarizations and slow unbinding on repolarization. CBD alteration of channel availability at various voltages suggested that CBD binds especially tightly [K d (dissociation constant), ∼150 nm] to the slow inactivated state of TTX-R channels, which can be substantially occupied at voltages as negative as -40 mV. Remarkably, CBD was more potent in inhibiting TTX-R channels and inhibiting action potential firing than the local anesthetic bupivacaine. We conclude that CBD might produce some of its analgesic effects by direct effects on neuronal excitability, with tight binding to the slow inactivated state of Nav1.8 channels contributing to effective inhibition of repetitive firing by modest depolarizations.SIGNIFICANCE STATEMENT Cannabidiol (CBD) has been shown to inhibit pain in various rodent models, but the mechanism of this effect is unknown. We describe the ability of CBD to inhibit repetitive action potential firing in primary nociceptive neurons from mouse dorsal root ganglia and analyze the effects on voltage-dependent sodium channels. We find that CBD interacts with TTX-resistant sodium channels in a state-dependent manner suggesting particularly tight binding to slow inactivated states of Nav1.8 channels, which dominate the overall inactivation of Nav1.8 channels for small maintained depolarizations from the resting potential. The results suggest that CBD can exert analgesic effects in part by directly inhibiting repetitive firing of primary nociceptors and suggest a strategy of identifying compounds that bind selectively to slow inactivated states of Nav1.8 channels for developing effective analgesics.
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