1
|
Brackx W, de Cássia Collaço R, Theys M, Cruyssen JV, Bosmans F. Understanding the physiological role of Na V1.9: Challenges and opportunities for pain modulation. Pharmacol Ther 2023; 245:108416. [PMID: 37061202 DOI: 10.1016/j.pharmthera.2023.108416] [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: 02/03/2023] [Revised: 03/31/2023] [Accepted: 04/12/2023] [Indexed: 04/17/2023]
Abstract
Voltage-activated Na+ (NaV) channels are crucial contributors to rapid electrical signaling in the human body. As such, they are among the most targeted membrane proteins by clinical therapeutics and natural toxins. Several of the nine mammalian NaV channel subtypes play a documented role in pain or other sensory processes such as itch, touch, and smell. While causal relationships between these subtypes and biological function have been extensively described, the physiological role of NaV1.9 is less understood. Yet, mutations in NaV1.9 can cause striking disease phenotypes related to sensory perception such as loss or gain of pain and chronic itch. Here, we explore our current knowledge of the mechanisms by which NaV1.9 may contribute to pain and elaborate on the challenges associated with establishing links between experimental conditions and human disease. This review also discusses the lack of comprehensive insights into NaV1.9-specific pharmacology, an unfortunate situation since modulatory compounds may have tremendous potential in the clinic to treat pain or as precision tools to examine the extent of NaV1.9 participation in sensory perception processes.
Collapse
Affiliation(s)
- Wayra Brackx
- Molecular Physiology and Neurophysics Group, Department of Basic and Applied Medical Sciences, University of Ghent, Ghent, Belgium
| | - Rita de Cássia Collaço
- Molecular Physiology and Neurophysics Group, Department of Basic and Applied Medical Sciences, University of Ghent, Ghent, Belgium
| | - Margaux Theys
- Molecular Physiology and Neurophysics Group, Department of Basic and Applied Medical Sciences, University of Ghent, Ghent, Belgium
| | - Jolien Vander Cruyssen
- Molecular Physiology and Neurophysics Group, Department of Basic and Applied Medical Sciences, University of Ghent, Ghent, Belgium
| | - Frank Bosmans
- Molecular Physiology and Neurophysics Group, Department of Basic and Applied Medical Sciences, University of Ghent, Ghent, Belgium.
| |
Collapse
|
2
|
Zybura AS, Sahoo FK, Hudmon A, Cummins TR. CaMKII Inhibition Attenuates Distinct Gain-of-Function Effects Produced by Mutant Nav1.6 Channels and Reduces Neuronal Excitability. Cells 2022; 11:2108. [PMID: 35805192 PMCID: PMC9266207 DOI: 10.3390/cells11132108] [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] [Received: 05/11/2022] [Revised: 06/16/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022] Open
Abstract
Aberrant Nav1.6 activity can induce hyperexcitability associated with epilepsy. Gain-of-function mutations in the SCN8A gene encoding Nav1.6 are linked to epilepsy development; however, the molecular mechanisms mediating these changes are remarkably heterogeneous and may involve post-translational regulation of Nav1.6. Because calcium/calmodulin-dependent protein kinase II (CaMKII) is a powerful modulator of Nav1.6 channels, we investigated whether CaMKII modulates disease-linked Nav1.6 mutants. Whole-cell voltage clamp recordings in ND7/23 cells show that CaMKII inhibition of the epilepsy-related mutation R850Q largely recapitulates the effects previously observed for WT Nav1.6. We also characterized a rare missense variant, R639C, located within a regulatory hotspot for CaMKII modulation of Nav1.6. Prediction software algorithms and electrophysiological recordings revealed gain-of-function effects for R639C mutant channel activity, including increased sodium currents and hyperpolarized activation compared to WT Nav1.6. Importantly, the R639C mutation ablates CaMKII phosphorylation at a key regulatory site, T642, and, in contrast to WT and R850Q channels, displays a distinct response to CaMKII inhibition. Computational simulations demonstrate that modeled neurons harboring the R639C or R850Q mutations are hyperexcitable, and simulating the effects of CaMKII inhibition on Nav1.6 activity in modeled neurons differentially reduced hyperexcitability. Acute CaMKII inhibition may represent a promising mechanism to attenuate gain-of-function effects produced by Nav1.6 mutations.
Collapse
Affiliation(s)
- Agnes S. Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Firoj K. Sahoo
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (F.K.S.); (A.H.)
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (F.K.S.); (A.H.)
| | - Theodore R. Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| |
Collapse
|
3
|
Spead O, Weaver CJ, Moreland T, Poulain FE. Live imaging of retinotectal mapping reveals topographic map dynamics and a previously undescribed role for Contactin 2 in map sharpening. Development 2021; 148:272618. [PMID: 34698769 DOI: 10.1242/dev.199584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 10/07/2021] [Indexed: 11/20/2022]
Abstract
Organization of neuronal connections into topographic maps is essential for processing information. Yet, our understanding of topographic mapping has remained limited by our inability to observe maps forming and refining directly in vivo. Here, we used Cre-mediated recombination of a new colorswitch reporter in zebrafish to generate the first transgenic model allowing the dynamic analysis of retinotectal mapping in vivo. We found that the antero-posterior retinotopic map forms early but remains dynamic, with nasal and temporal retinal axons expanding their projection domains over time. Nasal projections initially arborize in the anterior tectum but progressively refine their projection domain to the posterior tectum, leading to the sharpening of the retinotopic map along the antero-posterior axis. Finally, using a CRISPR-mediated mutagenesis approach, we demonstrate that the refinement of nasal retinal projections requires the adhesion molecule Contactin 2. Altogether, our study provides the first analysis of a topographic map maturing in real time in a live animal and opens new strategies for dissecting the molecular mechanisms underlying precise topographic mapping in vertebrates.
Collapse
Affiliation(s)
- Olivia Spead
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Cory J Weaver
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Trevor Moreland
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Fabienne E Poulain
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| |
Collapse
|
4
|
Grüner J, Stengel H, Werner C, Appeltshauser L, Sommer C, Villmann C, Doppler K. Anti-contactin-1 Antibodies Affect Surface Expression and Sodium Currents in Dorsal Root Ganglia. NEUROLOGY-NEUROIMMUNOLOGY & NEUROINFLAMMATION 2021; 8:8/5/e1056. [PMID: 34429341 PMCID: PMC8407150 DOI: 10.1212/nxi.0000000000001056] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 05/17/2021] [Indexed: 01/13/2023]
Abstract
Background and Objectives As autoantibodies to contactin-1 from patients with chronic inflammatory demyelinating polyradiculoneuropathy not only bind to the paranodes where they are supposed to cause conduction failure but also bind to other neuronal cell types, we aimed to investigate the effect of anti–contactin-1 autoantibodies on contactin-1 surface expression in cerebellar granule neurons, dorsal root ganglion neurons, and contactin-1–transfected human embryonic kidney 293 cells. Methods Immunocytochemistry including structured illumination microscopy and immunoblotting was used to determine expression levels of contactin-1 and/or sodium channels after long-term exposure to autoantibodies from 3 seropositive patients. For functional analysis of sodium channels, whole-cell recordings of sodium currents were performed on dorsal root ganglion neurons incubated with anti–contactin-1 autoantibodies. Results We found a reduction in contactin-1 expression levels on dorsal root ganglion neurons, cerebellar granule neurons, and contactin-1–transfected human embryonic kidney 293 cells and decreased dorsal root ganglion sodium currents after long-term exposure to anti–contactin-1 autoantibodies. Sodium channel density did not decrease. Discussion Our results demonstrate a direct effect of anti–contactin-1 autoantibodies on the surface expression of contactin-1 and sodium currents in dorsal root ganglion neurons. This may be the pathophysiologic correlate of sensory ataxia reported in these patients.
Collapse
Affiliation(s)
- Julia Grüner
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany
| | - Helena Stengel
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany
| | - Christian Werner
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany
| | - Luise Appeltshauser
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany
| | - Claudia Sommer
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany
| | - Carmen Villmann
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany
| | - Kathrin Doppler
- From the Department of Neurology (J.G., H.S., L.A., C.S., K.D.), University Hospital Würzburg, Germany; Department of Biotechnology and Biophysics (C.W.), Julius-Maximilians-University of Würzburg; and Institute of Clinical Neurobiology (C.V.), University Hospital, Julius-Maximilians-University of Würzburg, Germany.
| |
Collapse
|
5
|
Spider venom-derived peptide induces hyperalgesia in Na v1.7 knockout mice by activating Na v1.9 channels. Nat Commun 2020; 11:2293. [PMID: 32385249 PMCID: PMC7210961 DOI: 10.1038/s41467-020-16210-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 04/21/2020] [Indexed: 01/05/2023] Open
Abstract
The sodium channels Nav1.7, Nav1.8 and Nav1.9 are critical for pain perception in peripheral nociceptors. Loss of function of Nav1.7 leads to congenital insensitivity to pain in humans. Here we show that the spider peptide toxin called HpTx1, first identified as an inhibitor of Kv4.2, restores nociception in Nav1.7 knockout (Nav1.7-KO) mice by enhancing the excitability of dorsal root ganglion neurons. HpTx1 inhibits Nav1.7 and activates Nav1.9 but does not affect Nav1.8. This toxin produces pain in wild-type (WT) and Nav1.7-KO mice, and attenuates nociception in Nav1.9-KO mice, but has no effect in Nav1.8-KO mice. These data indicate that HpTx1-induced hypersensitivity is mediated by Nav1.9 activation and offers pharmacological insight into the relationship of the three Nav channels in pain signalling. Loss of function of Nav1.7 leads to congenital insensitivity to pain in humans. Here the authors found that activation of Nav1.9 can restore nociception in Nav1.7 knockout mice, revealed by a venom-derived peptide as a probe.
Collapse
|
6
|
Zhou Y, Cai S, Moutal A, Yu J, Gómez K, Madura CL, Shan Z, Pham NYN, Serafini MJ, Dorame A, Scott DD, François-Moutal L, Perez-Miller S, Patek M, Khanna M, Khanna R. The Natural Flavonoid Naringenin Elicits Analgesia through Inhibition of NaV1.8 Voltage-Gated Sodium Channels. ACS Chem Neurosci 2019; 10:4834-4846. [PMID: 31697467 DOI: 10.1021/acschemneuro.9b00547] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Naringenin (2S)-5,7-dihydroxy-2-(4-hydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-4-one is a natural flavonoid found in fruits from the citrus family. Because (2S)-naringenin is known to racemize, its bioactivity might be related to one or both enantiomers. Computational studies predicted that (2R)-naringenin may act on voltage-gated ion channels, particularly the N-type calcium channel (CaV2.2) and the NaV1.7 sodium channel-both of which are key for pain signaling. Here we set out to identify the possible mechanism of action of naringenin. Naringenin inhibited depolarization-evoked Ca2+ influx in acetylcholine-, ATP-, and capsaicin-responding rat dorsal root ganglion (DRG) neurons. This was corroborated in electrophysiological recordings from DRG neurons. Pharmacological dissection of each of the voltage-gated Ca2+ channels subtypes could not pinpoint any selectivity of naringenin. Instead, naringenin inhibited NaV1.8-dependent and tetrodotoxin (TTX)-resistant while sparing tetrodotoxin sensitive (TTX-S) voltage-gated Na+ channels as evidenced by the lack of further inhibition by the NaV1.8 blocker A-803467. The effects of the natural flavonoid were validated ex vivo in spinal cord slices where naringenin decreased both the frequency and amplitude of sEPSC recorded in neurons within the substantia gelatinosa. The antinociceptive potential of naringenin was evaluated in male and female mice. Naringenin had no effect on the nociceptive thresholds evoked by heat. Naringenin's reversed allodynia was in mouse models of postsurgical and neuropathic pain. Here, driven by a call by the National Center for Complementary and Integrative Health's strategic plan to advance fundamental research into basic biological mechanisms of the action of natural products, we advance the antinociceptive potential of the flavonoid naringenin.
Collapse
Affiliation(s)
- Yuan Zhou
- Department of Clinical Laboratory, the First Hospital of Jilin University, Changchun 130021, China
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Song Cai
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Jie Yu
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Kimberly Gómez
- Department of Physiology, Biophysics and Neuroscience, Centre for Research and Advanced Studies (Cinvestav), Mexico City 07360, Mexico
| | - Cynthia L. Madura
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Zhiming Shan
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Nancy Y. N. Pham
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Maria J. Serafini
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Angie Dorame
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - David D. Scott
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Liberty François-Moutal
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Samantha Perez-Miller
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
| | - Marcel Patek
- BrightRock Path Consulting, LLC, Tucson, Arizona 85721, United States
| | - May Khanna
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
- The Center for Innovation in Brain Sciences, The University of Arizona Health Sciences, Tucson, Arizona 85724, United States
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson 85724-5050, Arizona, United States
- The Center for Innovation in Brain Sciences, The University of Arizona Health Sciences, Tucson, Arizona 85724, United States
| |
Collapse
|
7
|
Bisphenol A Regulates Sodium Ramp Currents in Mouse Dorsal Root Ganglion Neurons and Increases Nociception. Sci Rep 2019; 9:10306. [PMID: 31312012 PMCID: PMC6635372 DOI: 10.1038/s41598-019-46769-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 07/05/2019] [Indexed: 12/02/2022] Open
Abstract
17β-Estradiol mediates the sensitivity to pain and is involved in sex differences in nociception. The widespread environmental disrupting chemical bisphenol A (BPA) has estrogenic activity, but its implications in pain are mostly unknown. Here we show that treatment of male mice with BPA (50 µg/kg/day) during 8 days, decreases the latency to pain behavior in response to heat, suggesting increased pain sensitivity. We demonstrate that incubation of dissociated dorsal root ganglia (DRG) nociceptors with 1 nM BPA increases the frequency of action potential firing. SCN9A encodes the voltage-gated sodium channel Nav1.7, which is present in DRG nociceptors and is essential in pain signaling. Nav1.7 and other voltage-gated sodium channels in mouse DRG are considered threshold channels because they produce ramp currents, amplifying small depolarizations and enhancing electrical activity. BPA increased Nav-mediated ramp currents elicited with slow depolarizations. Experiments using pharmacological tools as well as DRG from ERβ−/− mice indicate that this BPA effect involves ERα and phosphoinositide 3-kinase. The mRNA expression and biophysical properties other than ramp currents of Nav channels, were unchanged by BPA. Our data suggest that BPA at environmentally relevant doses affects the ability to detect noxious stimuli and therefore should be considered when studying the etiology of pain conditions.
Collapse
|
8
|
Bennett DL, Clark AJ, Huang J, Waxman SG, Dib-Hajj SD. The Role of Voltage-Gated Sodium Channels in Pain Signaling. Physiol Rev 2019; 99:1079-1151. [DOI: 10.1152/physrev.00052.2017] [Citation(s) in RCA: 256] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Acute pain signaling has a key protective role and is highly evolutionarily conserved. Chronic pain, however, is maladaptive, occurring as a consequence of injury and disease, and is associated with sensitization of the somatosensory nervous system. Primary sensory neurons are involved in both of these processes, and the recent advances in understanding sensory transduction and human genetics are the focus of this review. Voltage-gated sodium channels (VGSCs) are important determinants of sensory neuron excitability: they are essential for the initial transduction of sensory stimuli, the electrogenesis of the action potential, and neurotransmitter release from sensory neuron terminals. Nav1.1, Nav1.6, Nav1.7, Nav1.8, and Nav1.9 are all expressed by adult sensory neurons. The biophysical characteristics of these channels, as well as their unique expression patterns within subtypes of sensory neurons, define their functional role in pain signaling. Changes in the expression of VGSCs, as well as posttranslational modifications, contribute to the sensitization of sensory neurons in chronic pain states. Furthermore, gene variants in Nav1.7, Nav1.8, and Nav1.9 have now been linked to human Mendelian pain disorders and more recently to common pain disorders such as small-fiber neuropathy. Chronic pain affects one in five of the general population. Given the poor efficacy of current analgesics, the selective expression of particular VGSCs in sensory neurons makes these attractive targets for drug discovery. The increasing availability of gene sequencing, combined with structural modeling and electrophysiological analysis of gene variants, also provides the opportunity to better target existing therapies in a personalized manner.
Collapse
Affiliation(s)
- David L. Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Alex J. Clark
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Jianying Huang
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Stephen G. Waxman
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Sulayman D. Dib-Hajj
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| |
Collapse
|
9
|
Chatterjee M, Koel-Simmelink MJ, Verberk IM, Killestein J, Vrenken H, Enzinger C, Ropele S, Fazekas F, Khalil M, Teunissen CE. Contactin-1 and contactin-2 in cerebrospinal fluid as potential biomarkers for axonal domain dysfunction in multiple sclerosis. Mult Scler J Exp Transl Clin 2018; 4:2055217318819535. [PMID: 30627437 PMCID: PMC6305953 DOI: 10.1177/2055217318819535] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/31/2018] [Accepted: 11/22/2018] [Indexed: 01/06/2023] Open
Abstract
Background Contactin-1 and contactin-2 are important for the maintenance of axonal integrity. Objective To investigate the cerebrospinal fluid levels of contactin-1 and contactin-2 in multiple sclerosis patients and controls, and their potential use as prognostic markers for neurodegeneration. Methods Cerebrospinal fluid contactin-1 and contactin-2 were measured in relapsing–remitting multiple sclerosis (n = 41), secondary progressive multiple sclerosis (n = 26) and primary progressive multiple sclerosis patients (n = 13) and controls (n = 18), and in a second cohort with clinically isolated syndrome patients (n = 88, median clinical follow-up period of 2.3 years) and controls (n = 20). Correlations/linear regressions were analysed with other baseline cerebrospinal fluid axonal damage markers and cross-sectional/longitudinal magnetic resonance imaging features. Results Contactin-1 and contactin-2 levels were up to 1.4-fold reduced in relapsing–remitting multiple sclerosis (contactin-1: p = 0.01, contactin-2: p = 0.02) and secondary progressive multiple sclerosis (contactin-1: p = 0.05, contactin-2: p = 0.02) compared to controls. In clinically isolated syndrome patients, contactin-1 tended to increase when compared to controls (p = 0.07). Both contactin-1 and contactin-2 correlated with neurofilament light, neurofilament heavy and magnetic resonance imaging metrics differently depending on the disease stage. In clinically isolated syndrome patients, baseline contactin-2 level (β = –0.42, p = 0.04) predicted the longitudinal decline in cortex volume. Conclusion Cerebrospinal fluid contactin-1 and contactin-2 reveal axonal dysfunction in various stages of multiple sclerosis and their inclusion to the biomarker panel may provide better insight into the extent of axonal damage/dysfunction.
Collapse
Affiliation(s)
- Madhurima Chatterjee
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Marleen Ja Koel-Simmelink
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Inge Mw Verberk
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Joep Killestein
- Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Hugo Vrenken
- Department of Radiology, VU University Medical Center, Amsterdam UMC, The Netherlands
| | | | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Austria
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Austria
| | - Michael Khalil
- Department of Neurology, Medical University of Graz, Austria
| | - Charlotte E Teunissen
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| |
Collapse
|
10
|
Touska F, Turnquist B, Vlachova V, Reeh PW, Leffler A, Zimmermann K. Heat-resistant action potentials require TTX-resistant sodium channels Na V1.8 and Na V1.9. J Gen Physiol 2018; 150:1125-1144. [PMID: 29970412 PMCID: PMC6080895 DOI: 10.1085/jgp.201711786] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 12/31/2017] [Accepted: 05/29/2018] [Indexed: 12/13/2022] Open
Abstract
Nociceptors prevent damage by being able to detect and transmit noxious stimuli, such as hot temperatures. Touska et al. show that the TTX-resistant NaV channels, NaV1.8 and NaV1.9, are required for heat-resistant nociceptors to encode noxious heat and that the current through NaV1.9 increases at higher temperatures. Damage-sensing nociceptors in the skin provide an indispensable protective function thanks to their specialized ability to detect and transmit hot temperatures that would block or inflict irreversible damage in other mammalian neurons. Here we show that the exceptional capacity of skin C-fiber nociceptors to encode noxiously hot temperatures depends on two tetrodotoxin (TTX)-resistant sodium channel α-subunits: NaV1.8 and NaV1.9. We demonstrate that NaV1.9, which is commonly considered an amplifier of subthreshold depolarizations at 20°C, undergoes a large gain of function when temperatures rise to the pain threshold. We also show that this gain of function renders NaV1.9 capable of generating action potentials with a clear inflection point and positive overshoot. In the skin, heat-resistant nociceptors appear as two distinct types with unique and possibly specialized features: one is blocked by TTX and relies on NaV1.9, and the second type is insensitive to TTX and composed of both NaV1.8 and NaV1.9. Independent of rapidly gated TTX-sensitive NaV channels that form the action potential at pain threshold, NaV1.8 is required in all heat-resistant nociceptors to encode temperatures higher than ∼46°C, whereas NaV1.9 is crucial for shaping the action potential upstroke and keeping the NaV1.8 voltage threshold within reach.
Collapse
Affiliation(s)
- Filip Touska
- Klinik für Anästhesiologie am Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.,Department of Cellular Neurophysiology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Brian Turnquist
- Department of Mathematics and Computer Science, Bethel University, St. Paul, MN
| | - Viktorie Vlachova
- Department of Cellular Neurophysiology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Peter W Reeh
- Department of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Andreas Leffler
- Klinik für Anästhesiologie und Intensivmedizin, Medizinische Hochschule Hannover, Hannover, Germany
| | - Katharina Zimmermann
- Klinik für Anästhesiologie am Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| |
Collapse
|
11
|
Zhou X, Zhang Y, Tang D, Liang S, Chen P, Tang C, Liu Z. A Chimeric NaV1.8 Channel Expression System Based on HEK293T Cell Line. Front Pharmacol 2018; 9:337. [PMID: 29686617 PMCID: PMC5900924 DOI: 10.3389/fphar.2018.00337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/22/2018] [Indexed: 11/13/2022] Open
Abstract
Among the nine voltage-gated sodium channel (NaV) subtypes, NaV1.8 is an attractive therapeutic target for pain. The heterologous expression of recombinant NaV1.8 currents is of particular importance for its electrophysiological and pharmacological studies. However, NaV1.8 expresses no or low-level functional currents when transiently transfected into non-neuronal cell lines. The present study aims to explore the molecular determinants limiting its functional expression and accordingly establish a functional NaV1.8 expression system. We conducted screening analysis of the NaV1.8 intracellular loops by constructing NaV chimeric channels and confirmed that the NaV1.8 C-terminus was the only limiting factor. Replacing this sequence with that of NaV1.4, NaV1.5, or NaV1.7 constructed functional channels (NaV1.8/1.4L5, NaV1.8/1.5L5, and NaV1.8/1.7L5, respectively), which expressed high-level NaV1.8-like currents in HEK293T cells. The chimeric channel NaV1.8/1.7L5 displayed much faster inactivation of its macroscopic currents than NaV1.8/1.4L5 and NaV1.8/1.5L5, and it was the most similar to wild-type NaV1.8 expressed in ND7/23 cells. Its currents were very stable during repetitive depolarizations, while its repriming kinetic was different from wild-type NaV1.8. Most importantly, NaV1.8/1.7L5 pharmacologically resembled wild-type NaV1.8 as revealed by testing their susceptibility to two NaV1.8 selective antagonists, APETx-2 and MrVIB. NaV chimeras study showed that at least the domain 2 and domain 4 of NaV1.8 were involved in binding with APETx-2. Our study provided new insights into the function of NaV1.8 intracellular loops, as well as a reliable and convenient expression system which could be useful in NaV1.8 studies.
Collapse
Affiliation(s)
| | | | | | | | | | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| |
Collapse
|
12
|
Sodium Channel Na v1.8 Underlies TTX-Resistant Axonal Action Potential Conduction in Somatosensory C-Fibers of Distal Cutaneous Nerves. J Neurosci 2017; 37:5204-5214. [PMID: 28450535 DOI: 10.1523/jneurosci.3799-16.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (NaV) channels are responsible for the initiation and conduction of action potentials within primary afferents. The nine NaV channel isoforms recognized in mammals are often functionally divided into tetrodotoxin (TTX)-sensitive (TTX-s) channels (NaV1.1-NaV1.4, NaV1.6-NaV1.7) that are blocked by nanomolar concentrations and TTX-resistant (TTX-r) channels (NaV1.8 and NaV1.9) inhibited by millimolar concentrations, with NaV1.5 having an intermediate toxin sensitivity. For small-diameter primary afferent neurons, it is unclear to what extent different NaV channel isoforms are distributed along the peripheral and central branches of their bifurcated axons. To determine the relative contribution of TTX-s and TTX-r channels to action potential conduction in different axonal compartments, we investigated the effects of TTX on C-fiber-mediated compound action potentials (C-CAPs) of proximal and distal peripheral nerve segments and dorsal roots from mice and pigtail monkeys (Macaca nemestrina). In the dorsal roots and proximal peripheral nerves of mice and nonhuman primates, TTX reduced the C-CAP amplitude to 16% of the baseline. In contrast, >30% of the C-CAP was resistant to TTX in distal peripheral branches of monkeys and WT and NaV1.9-/- mice. In nerves from NaV1.8-/- mice, TTX-r C-CAPs could not be detected. These data indicate that NaV1.8 is the primary isoform underlying TTX-r conduction in distal axons of somatosensory C-fibers. Furthermore, there is a differential spatial distribution of NaV1.8 within C-fiber axons, being functionally more prominent in the most distal axons and terminal regions. The enrichment of NaV1.8 in distal axons may provide a useful target in the treatment of pain of peripheral origin.SIGNIFICANCE STATEMENT It is unclear whether individual sodium channel isoforms exert differential roles in action potential conduction along the axonal membrane of nociceptive, unmyelinated peripheral nerve fibers, but clarifying the role of sodium channel subtypes in different axonal segments may be useful for the development of novel analgesic strategies. Here, we provide evidence from mice and nonhuman primates that a substantial portion of the C-fiber compound action potential in distal peripheral nerves, but not proximal nerves or dorsal roots, is resistant to tetrodotoxin and that, in mice, this effect is mediated solely by voltage-gated sodium channel 1.8 (NaV1.8). The functional prominence of NaV1.8 within the axonal compartment immediately proximal to its termination may affect strategies targeting pain of peripheral origin.
Collapse
|
13
|
Wu Y, Zou B, Liang L, Li M, Tao YX, Yu H, Wang X, Li M. Loperamide inhibits sodium channels to alleviate inflammatory hyperalgesia. Neuropharmacology 2017; 117:282-291. [PMID: 28216001 DOI: 10.1016/j.neuropharm.2017.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 02/10/2017] [Accepted: 02/12/2017] [Indexed: 12/25/2022]
Abstract
Previous studies demonstrated that Loperamide, originally known as an anti-diarrheal drug, is a promising analgesic agent primarily targeting mu-opioid receptors. However some evidences suggested that non-opioid mechanisms may be contributing to its analgesic effect. In the present study, Loperamide was identified as a Nav1.7 blocker in a pilot screen. In HEK293 cells expressing Nav1.7 sodium channels, Loperamide blocked the resting state of Nav1.7 channels (IC50 = 1.86 ± 0.11 μM) dose-dependently and reversibly. Loperamide produced a 10.4 mV of hyperpolarizing shift for the steady-state inactivation of Nav1.7 channels without apparent effect on the voltage-dependent activation. The drug displayed a mild use- and state-dependent inhibition on Nav1.7 channels, which was removed by the local anesthetic-insensitive construct Nav1.7-F1737A. Inhibition of Nav1.7 at resting state was not altered significantly by the F1737A mutation. Compared to its effects on Nav1.7, Loperamide exhibited higher potency on recombinant Nav1.8 channels in ND7/23 cells (IC50 = 0.60 ± 0.10 μM) and weaker potency on Nav1.9 channels (3.48 ± 0.33 μM). Notably more pronounced inhibition was observed in the native Nav1.8 channels (0.11 ± 0.08 μM) in DRG neurons. Once mu-opioid receptor was antagonized by Naloxone in DRG neurons, potency of Loperamide on Nav1.8 was identical to that of recombinant Nav1.8 channels. The inhibition on Nav channels may be the main mechanism of Loperamide for pain relief beyond mu-opioid receptor. In the meanwhile, the opioid receptor pathway may also influence the blocking effect of Loperamide on sodium channels, implying a cross-talk between sodium channels and opioid receptors in pain processing.
Collapse
Affiliation(s)
- Ying Wu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Beiyan Zou
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center and Johns Hopkins Ion Channel Center, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Min Li
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Haibo Yu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
| | - Xiaoliang Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
| | - Min Li
- The Solomon H. Snyder Department of Neuroscience, High Throughput Biology Center and Johns Hopkins Ion Channel Center, Johns Hopkins University, Baltimore, MD 21205, USA.
| |
Collapse
|
14
|
Hockley JRF, Winchester WJ, Bulmer DC. The voltage-gated sodium channel NaV 1.9 in visceral pain. Neurogastroenterol Motil 2016; 28:316-26. [PMID: 26462871 DOI: 10.1111/nmo.12698] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/06/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Visceral pain is a common symptom for patients with gastrointestinal (GI) disease. It is unpleasant, debilitating, and represents a large unmet medical need for effective clinical treatments. Recent studies have identified NaV 1.9 as an important regulator of afferent sensitivity in visceral pain pathways to mechanical and inflammatory stimuli, suggesting that NaV 1.9 could represent an important therapeutic target for the treatment of visceral pain. This potential has been highlighted by the identification of patients who have an insensitivity to pain or painful neuropathies associated with mutations in SCN11A, the gene encoding voltage-gated sodium channel subtype 1.9 (NaV 1.9). PURPOSE Here, we address the role of NaV 1.9 in visceral pain and what known human NaV 1.9 mutants can tell us about NaV 1.9 function in gut physiology and pathophysiology.
Collapse
Affiliation(s)
- J R F Hockley
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.,National Centre for Bowel Research and Surgical Innovation, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | | | - D C Bulmer
- Wingate Institute of Neurogastroenterology, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.,National Centre for Bowel Research and Surgical Innovation, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| |
Collapse
|
15
|
Luiz AP, Wood JN. Sodium Channels in Pain and Cancer: New Therapeutic Opportunities. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 75:153-78. [PMID: 26920012 DOI: 10.1016/bs.apha.2015.12.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Voltage-gated sodium channels (VGSCs) underpin electrical activity in the nervous system through action potential propagation. First predicted by the modeling studies of Hodgkin and Huxley, they were subsequently identified at the molecular level by groups led by Catterall and Numa. VGSC dysfunction has long been linked to neuronal and cardiac disorders with some nonselective sodium channel blockers in current use in the clinic. The lack of selectivity means that side effect issues are a major impediment to the use of broad spectrum sodium channel blockers. Nine different sodium channels are known to exist, and selective blockers are now being developed. The potential utility of these drugs to target diseases ranging from migraine, multiple sclerosis, muscle, and immune system disorders, to cancer and pain is being explored. Four channels are potential targets for pain disorders. This conclusion comes from mouse knockout studies and human mutations that prove the involvement of Nav1.3, Nav1.7, Nav1.8, and Nav1.9 in the development and maintenance of acute and chronic pain. In this chapter, we present a short overview of the possible role of Nav1.3, Nav1.7, Nav1.8, and Nav1.9 in human pain and the emerging and unexpected role of sodium channels in cancer pathogenesis.
Collapse
Affiliation(s)
- Ana Paula Luiz
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - John N Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, United Kingdom.
| |
Collapse
|
16
|
Bao L. Trafficking regulates the subcellular distribution of voltage-gated sodium channels in primary sensory neurons. Mol Pain 2015; 11:61. [PMID: 26423360 PMCID: PMC4590712 DOI: 10.1186/s12990-015-0065-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/23/2015] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Navs) comprise at least nine pore-forming α subunits. Of these, Nav1.6, Nav1.7, Nav1.8 and Nav1.9 are the most frequently studied in primary sensory neurons located in the dorsal root ganglion and are mainly localized to the cytoplasm. A large pool of intracellular Navs raises the possibility that changes in Nav trafficking could alter channel function. The molecular mediators of Nav trafficking mainly consist of signals within the Navs themselves, interacting proteins and extracellular factors. The surface expression of Navs is achieved by escape from the endoplasmic reticulum and proteasome degradation, forward trafficking and plasma membrane anchoring, and it is also regulated by channel phosphorylation and ubiquitination in primary sensory neurons. Axonal transport and localization of Navs in afferent fibers involves the motor protein KIF5B and scaffold proteins, including contactin and PDZ domain containing 2. Localization of Nav1.6 to the nodes of Ranvier in myelinated fibers of primary sensory neurons requires node formation and the submembrane cytoskeletal protein complex. These findings inform our understanding of the molecular and cellular mechanisms underlying Nav trafficking in primary sensory neurons.
Collapse
Affiliation(s)
- Lan Bao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai, 200031, China.
| |
Collapse
|
17
|
Carmean V, Yonkers MA, Tellez MB, Willer JR, Willer GB, Gregg RG, Geisler R, Neuhauss SC, Ribera AB. pigk Mutation underlies macho behavior and affects Rohon-Beard cell excitability. J Neurophysiol 2015; 114:1146-57. [PMID: 26133798 DOI: 10.1152/jn.00355.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/25/2015] [Indexed: 12/20/2022] Open
Abstract
The study of touch-evoked behavior allows investigation of both the cells and circuits that generate a response to tactile stimulation. We investigate a touch-insensitive zebrafish mutant, macho (maco), previously shown to have reduced sodium current amplitude and lack of action potential firing in sensory neurons. In the genomes of mutant but not wild-type embryos, we identify a mutation in the pigk gene. The encoded protein, PigK, functions in attachment of glycophosphatidylinositol anchors to precursor proteins. In wild-type embryos, pigk mRNA is present at times when mutant embryos display behavioral phenotypes. Consistent with the predicted loss of function induced by the mutation, knock-down of PigK phenocopies maco touch insensitivity and leads to reduced sodium current (INa) amplitudes in sensory neurons. We further test whether the genetic defect in pigk underlies the maco phenotype by overexpressing wild-type pigk in mutant embryos. We find that ubiquitous expression of wild-type pigk rescues the touch response in maco mutants. In addition, for maco mutants, expression of wild-type pigk restricted to sensory neurons rescues sodium current amplitudes and action potential firing in sensory neurons. However, expression of wild-type pigk limited to sensory cells of mutant embryos does not allow rescue of the behavioral touch response. Our results demonstrate an essential role for pigk in generation of the touch response beyond that required for maintenance of proper INa density and action potential firing in sensory neurons.
Collapse
Affiliation(s)
- V Carmean
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - M A Yonkers
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - M B Tellez
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - J R Willer
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and
| | - G B Willer
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and
| | - R G Gregg
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and
| | - R Geisler
- Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
| | - S C Neuhauss
- Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany
| | - A B Ribera
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
| |
Collapse
|
18
|
Vasylyev DV, Han C, Zhao P, Dib-Hajj S, Waxman SG. Dynamic-clamp analysis of wild-type human Nav1.7 and erythromelalgia mutant channel L858H. J Neurophysiol 2014; 111:1429-43. [DOI: 10.1152/jn.00763.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The link between sodium channel Nav1.7 and pain has been strengthened by identification of gain-of-function mutations in patients with inherited erythromelalgia (IEM), a genetic model of neuropathic pain in humans. A firm mechanistic link to nociceptor dysfunction has been precluded because assessments of the effect of the mutations on nociceptor function have thus far depended on electrophysiological recordings from dorsal root ganglia (DRG) neurons transfected with wild-type (WT) or mutant Nav1.7 channels, which do not permit accurate calibration of the level of Nav1.7 channel expression. Here, we report an analysis of the function of WT Nav1.7 and IEM L858H mutation within small DRG neurons using dynamic-clamp. We describe the functional relationship between current threshold for action potential generation and the level of WT Nav1.7 conductance in primary nociceptive neurons and demonstrate the basis for hyperexcitability at physiologically relevant levels of L858H channel conductance. We demonstrate that the L858H mutation, when modeled using dynamic-clamp at physiological levels within DRG neurons, produces a dramatically enhanced persistent current, resulting in 27-fold amplification of net sodium influx during subthreshold depolarizations and even greater amplification during interspike intervals, which provide a mechanistic basis for reduced current threshold and enhanced action potential firing probability. These results show, for the first time, a linear correlation between the level of Nav1.7 conductance and current threshold in DRG neurons. Our observations demonstrate changes in sodium influx that provide a mechanistic link between the altered biophysical properties of a mutant Nav1.7 channel and nociceptor hyperexcitability underlying the pain phenotype in IEM.
Collapse
Affiliation(s)
- Dmytro V. Vasylyev
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Chongyang Han
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Peng Zhao
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Sulayman Dib-Hajj
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| |
Collapse
|
19
|
Belkouch M, Dansereau MA, Tétreault P, Biet M, Beaudet N, Dumaine R, Chraibi A, Mélik-Parsadaniantz S, Sarret P. Functional up-regulation of Nav1.8 sodium channel in Aβ afferent fibers subjected to chronic peripheral inflammation. J Neuroinflammation 2014; 11:45. [PMID: 24606981 PMCID: PMC4007624 DOI: 10.1186/1742-2094-11-45] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/21/2014] [Indexed: 02/05/2023] Open
Abstract
Background Functional alterations in the properties of Aβ afferent fibers may account for the increased pain sensitivity observed under peripheral chronic inflammation. Among the voltage-gated sodium channels involved in the pathophysiology of pain, Nav1.8 has been shown to participate in the peripheral sensitization of nociceptors. However, to date, there is no evidence for a role of Nav1.8 in controlling Aβ-fiber excitability following persistent inflammation. Methods Distribution and expression of Nav1.8 in dorsal root ganglia and sciatic nerves were qualitatively or quantitatively assessed by immunohistochemical staining and by real time-polymerase chain reaction at different time points following complete Freund’s adjuvant (CFA) administration. Using a whole-cell patch-clamp configuration, we further determined both total INa and TTX-R Nav1.8 currents in large-soma dorsal root ganglia (DRG) neurons isolated from sham or CFA-treated rats. Finally, we analyzed the effects of ambroxol, a Nav1.8-preferring blocker on the electrophysiological properties of Nav1.8 currents and on the mechanical sensitivity and inflammation of the hind paw in CFA-treated rats. Results Our findings revealed that Nav1.8 is up-regulated in NF200-positive large sensory neurons and is subsequently anterogradely transported from the DRG cell bodies along the axons toward the periphery after CFA-induced inflammation. We also demonstrated that both total INa and Nav1.8 peak current densities are enhanced in inflamed large myelinated Aβ-fiber neurons. Persistent inflammation leading to nociception also induced time-dependent changes in Aβ-fiber neuron excitability by shifting the voltage-dependent activation of Nav1.8 in the hyperpolarizing direction, thus decreasing the current threshold for triggering action potentials. Finally, we found that ambroxol significantly reduces the potentiation of Nav1.8 currents in Aβ-fiber neurons observed following intraplantar CFA injection and concomitantly blocks CFA-induced mechanical allodynia, suggesting that Nav1.8 regulation in Aβ-fibers contributes to inflammatory pain. Conclusions Collectively, these findings support a key role for Nav1.8 in controlling the excitability of Aβ-fibers and its potential contribution to the development of mechanical allodynia under persistent inflammation.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Philippe Sarret
- Department of Physiology and Biophysics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, Quebec J1H 5N4, Canada.
| |
Collapse
|
20
|
Contactin-1 regulates myelination and nodal/paranodal domain organization in the central nervous system. Proc Natl Acad Sci U S A 2014; 111:E394-403. [PMID: 24385581 DOI: 10.1073/pnas.1313769110] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Myelin, a multilayered membrane sheath formed by oligodendrocytes around axons in the CNS, enables rapid nerve impulse conduction and sustains neuronal health. The signals exchanged between axons and oligodendrocytes in myelin remain to be fully elucidated. Here we provide genetic evidence for multiple and critical functions of Contactin-1 in central myelin. We document dynamic Contactin-1 expression on oligodendrocytes in vivo, and progressive accumulation at nodes of Ranvier and paranodes during postnatal mouse development. Nodal and paranodal expression stabilized in mature myelin, but overall membranous expression diminished. Contactin-1-deficiency disrupted paranodal junction formation as evidenced by loss of Caspr, mislocalized potassium Kv1.2 channels, and abnormal myelin terminal loops. Reduced numbers and impaired maturation of sodium channel clusters accompanied this phenotype. Histological, electron microscopic, and biochemical analyses uncovered significant hypomyelination in Contactin-1-deficient central nerves, with up to 60% myelin loss. Oligodendrocytes were present in normal numbers, albeit a minor population of neuronal/glial antigen 2-positive (NG2(+)) progenitors lagged in maturation by postnatal day 18, when the mouse null mutation was lethal. Major contributing factors to hypomyelination were defects in the generation and organization of myelin membranes, as judged by electron microscopy and quantitative analysis of oligodendrocyte processes labeled by GFP transgenically expressed from the proteolipid protein promoter. These data reveal that Contactin-1 regulates both myelin formation and organization of nodal and paranodal domains in the CNS. These multiple roles distinguish central Contactin-1 functions from its specific role at paranodes in the periphery, and emphasize mechanistic differences in central and peripheral myelination.
Collapse
|
21
|
KIF5B promotes the forward transport and axonal function of the voltage-gated sodium channel Nav1.8. J Neurosci 2013; 33:17884-96. [PMID: 24198377 DOI: 10.1523/jneurosci.0539-13.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nav1.8 is a tetrodotoxin-resistant voltage-gated sodium channel selectively expressed in primary sensory neurons. Peripheral inflammation and nerve injury induce Nav1.8 accumulation in peripheral nerves. However, the mechanisms and related significance of channel accumulation in nerves remains unclear. Here we report that KIF5B promotes the forward transport of Nav1.8 to the plasma membrane and axons in dorsal root ganglion (DRG) neurons of the rat. In peripheral inflammation induced through the intraplantar injection of complete Freund's adjuvant, increased KIF5 and Nav1.8 accumulation were observed in the sciatic nerve. The knock-down of KIF5B, a highly expressed member of the KIF5 family in DRGs, reduced the current density of Nav1.8 in both cultured DRG neurons and ND7-23 cells. Overexpression of KIF5B in ND7-23 cells increased the current density and surface expression of Nav1.8, which were abolished through brefeldin A treatment, whereas the increases were lost in KIF5B mutants defective in ATP hydrolysis or cargo binding. Overexpression of KIF5B also decreased the proteasome-associated degradation of Nav1.8. In addition, coimmunoprecipitation experiments showed interactions between the N terminus of Nav1.8 and the 511-620 aa sequence in the stalk domain of KIF5B. Furthermore, KIF5B increased Nav1.8 accumulation, Nav1.8 current, and neuronal excitability detected in the axons of cultured DRG neurons, which were completely abolished by the disruption of interactions between KIF5B and the N terminus of Nav1.8. Therefore, our results reveal that KIF5B is required for the forward transport and axonal function of Nav1.8, suggesting a mechanism for axonal accumulation of Nav1.8 in inflammatory pain.
Collapse
|
22
|
Blockade of Nav1.8 Currents in Nociceptive Trigeminal Neurons Contributes to Anti-trigeminovascular Nociceptive Effect of Amitriptyline. Neuromolecular Med 2013; 16:308-21. [DOI: 10.1007/s12017-013-8282-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/08/2013] [Indexed: 01/22/2023]
|
23
|
Vanoye CG, Kunic JD, Ehring GR, George AL. Mechanism of sodium channel NaV1.9 potentiation by G-protein signaling. ACTA ACUST UNITED AC 2013; 141:193-202. [PMID: 23359282 PMCID: PMC3557314 DOI: 10.1085/jgp.201210919] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tetrodotoxin (TTX)-resistant voltage-gated Na (Na(V)) channels have been implicated in nociception. In particular, Na(V)1.9 contributes to expression of persistent Na current in small diameter, nociceptive sensory neurons in dorsal root ganglia and is required for inflammatory pain sensation. Using ND7/23 cells stably expressing human Na(V)1.9, we elucidated the biophysical mechanisms responsible for potentiation of channel activity by G-protein signaling to better understand the response to inflammatory mediators. Heterologous Na(V)1.9 expression evoked TTX-resistant Na current with peak activation at -40 mV with extensive overlap in voltage dependence of activation and inactivation. Inactivation kinetics were slow and incomplete, giving rise to large persistent Na currents. Single-channel recording demonstrated long openings and correspondingly high open probability (P(o)) accounting for the large persistent current amplitude. Channels exposed to intracellular GTPγS, a proxy for G-protein signaling, exhibited twofold greater current density, slowing of inactivation, and a depolarizing shift in voltage dependence of inactivation but no change in activation voltage dependence. At the single-channel level, intracellular GTPγS had no effect on single-channel amplitude but caused an increased mean open time and greater P(o) compared with recordings made in the absence of GTPγS. We conclude that G-protein activation potentiates human Na(V)1.9 activity by increasing channel open probability and mean open time, causing the larger peak and persistent current, respectively. Our results advance our understanding about the mechanism of Na(V)1.9 potentiation by G-protein signaling during inflammation and provide a cellular platform useful for the discovery of Na(V)1.9 modulators with potential utility in treating inflammatory pain.
Collapse
Affiliation(s)
- Carlos G Vanoye
- Department of Medicine, Vanderbilt University, Nashville, TN 37232, USA
| | | | | | | |
Collapse
|
24
|
Malone M, Gary D, Yang IH, Miglioretti A, Houdayer T, Thakor N, McDonald J. Neuronal activity promotes myelination via a cAMP pathway. Glia 2013; 61:843-54. [PMID: 23554117 DOI: 10.1002/glia.22476] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 01/11/2013] [Indexed: 12/17/2022]
Abstract
Neuronal activity promotes myelination in vivo and in vitro. However, the molecular events that mediate activity-dependent myelination are not completely understood. Seven, daily 1 h sessions of patterned electrical stimulation (ESTIM) promoted myelin segment formation in mixed cultures of dorsal root ganglion (DRG) neurons and oligodendrocytes (OLs); the increase in myelination was frequency-dependent. Myelin segment formation was also enhanced following exposure of DRGs to ESTIM prior to OL addition, suggesting that ESTIM promotes myelination in a manner involving neuron-specific signaling. Cyclic adenosine monophosphate (cAMP) levels in DRGs were increased three-fold following ESTIM, and artificially increasing cAMP mimicked the ability of ESTIM to promote myelination. Alternatively, inhibiting the cAMP pathway suppressed ESTIM-induced myelination. We used compartmentalized, microfluidic platforms to isolate DRG soma from OLs and assessed cell-type specific effects of ESTIM on myelination. A selective increase or decrease in DRG cAMP levels resulted in enhanced or suppressed myelination, respectively. This work describes a novel role for the cAMP pathway in neurons that results in enhanced myelination.
Collapse
Affiliation(s)
- Misti Malone
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | | | | | | | | |
Collapse
|
25
|
Malykhina AP, Lei Q, Erickson CS, Epstein ML, Saban MR, Davis CA, Saban R. VEGF induces sensory and motor peripheral plasticity, alters bladder function, and promotes visceral sensitivity. BMC PHYSIOLOGY 2012; 12:15. [PMID: 23249422 PMCID: PMC3543727 DOI: 10.1186/1472-6793-12-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/11/2012] [Indexed: 12/30/2022]
Abstract
BACKGROUND This work tests the hypothesis that bladder instillation with vascular endothelial growth factor (VEGF) modulates sensory and motor nerve plasticity, and, consequently, bladder function and visceral sensitivity.In addition to C57BL/6J, ChAT-cre mice were used for visualization of bladder cholinergic nerves. The direct effect of VEGF on the density of sensory nerves expressing the transient receptor potential vanilloid subfamily 1 (TRPV1) and cholinergic nerves (ChAT) was studied one week after one or two intravesical instillations of the growth factor.To study the effects of VEGF on bladder function, mice were intravesically instilled with VEGF and urodynamic evaluation was assessed. VEGF-induced alteration in bladder dorsal root ganglion (DRG) neurons was performed on retrogradly labeled urinary bladder afferents by patch-clamp recording of voltage gated Na+ currents. Determination of VEGF-induced changes in sensitivity to abdominal mechanostimulation was performed by application of von Frey filaments. RESULTS In addition to an overwhelming increase in TRPV1 immunoreactivity, VEGF instillation resulted in an increase in ChAT-directed expression of a fluorescent protein in several layers of the urinary bladder. Intravesical VEGF caused a profound change in the function of the urinary bladder: acute VEGF (1 week post VEGF treatment) reduced micturition pressure and longer treatment (2 weeks post-VEGF instillation) caused a substantial reduction in inter-micturition interval. In addition, intravesical VEGF resulted in an up-regulation of voltage gated Na(+) channels (VGSC) in bladder DRG neurons and enhanced abdominal sensitivity to mechanical stimulation. CONCLUSIONS For the first time, evidence is presented indicating that VEGF instillation into the mouse bladder promotes a significant increase in peripheral nerve density together with alterations in bladder function and visceral sensitivity. The VEGF pathway is being proposed as a key modulator of neural plasticity in the pelvis and enhanced VEGF content may be associated with visceral hyperalgesia, abdominal discomfort, and/or pelvic pain.
Collapse
Affiliation(s)
- Anna P Malykhina
- Department of Surgery, Division of Urology, University of Pennsylvania School of Medicine, Glenolden, 19036-2307, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Black JA, Frézel N, Dib-Hajj SD, Waxman SG. Expression of Nav1.7 in DRG neurons extends from peripheral terminals in the skin to central preterminal branches and terminals in the dorsal horn. Mol Pain 2012; 8:82. [PMID: 23134641 PMCID: PMC3517774 DOI: 10.1186/1744-8069-8-82] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/30/2012] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Sodium channel Nav1.7 has emerged as a target of considerable interest in pain research, since loss-of-function mutations in SCN9A, the gene that encodes Nav1.7, are associated with a syndrome of congenital insensitivity to pain, gain-of-function mutations are linked to the debiliting chronic pain conditions erythromelalgia and paroxysmal extreme pain disorder, and upregulated expression of Nav1.7 accompanies pain in diabetes and inflammation. Since Nav1.7 has been implicated as playing a critical role in pain pathways, we examined by immunocytochemical methods the expression and distribution of Nav1.7 in rat dorsal root ganglia neurons, from peripheral terminals in the skin to central terminals in the spinal cord dorsal horn. RESULTS Nav1.7 is robustly expressed within the somata of peptidergic and non-peptidergic DRG neurons, and along the peripherally- and centrally-directed C-fibers of these cells. Nav1.7 is also expressed at nodes of Ranvier in a subpopulation of Aδ-fibers within sciatic nerve and dorsal root. The peripheral terminals of DRG neurons within skin, intraepidermal nerve fibers (IENF), exhibit robust Nav1.7 immunolabeling. The central projections of DRG neurons in the superficial lamina of spinal cord dorsal horn also display Nav1.7 immunoreactivity which extends to presynaptic terminals. CONCLUSIONS The expression of Nav1.7 in DRG neurons extends from peripheral terminals in the skin to preterminal central branches and terminals in the dorsal horn. These data support a major contribution for Nav1.7 in pain pathways, including action potential electrogenesis, conduction along axonal trunks and depolarization/invasion of presynaptic axons. The findings presented here may be important for pharmaceutical development, where target engagement in the right compartment is essential.
Collapse
Affiliation(s)
- Joel A Black
- Department of Neurology and Paralyzed Veterans of America Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA.
| | | | | | | |
Collapse
|
27
|
Sodium channel Na(v)1.7 is essential for lowering heat pain threshold after burn injury. J Neurosci 2012; 32:10819-32. [PMID: 22875917 DOI: 10.1523/jneurosci.0304-12.2012] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Marked hypersensitivity to heat and mechanical (pressure) stimuli develop after a burn injury, but the neural mechanisms underlying these effects are poorly understood. In this study, we establish a new mouse model of focal second-degree burn injury to investigate the molecular and cellular basis for burn injury-induced pain. This model features robust injury-induced behavioral effects and tissue-specific altered cytokine profile, but absence of glial activation in spinal dorsal horn. Three voltage-gated sodium channels, Na(v)1.7, Na(v)1.8, and Na(v)1.9, are preferentially expressed in peripheral somatosensory neurons of the dorsal root ganglia (DRGs) and have been implicated in injury-induced neuronal hyperexcitability. Using knock-out mice, we provide evidence that Na(v)1.7 selectively contributes to burn-induced hypersensitivity to heat, but not mechanical, stimuli. After burn model injury, wild-type mice display increased sensitivity to heat stimuli, and a normally non-noxious warm stimulus induces activity-dependent Fos expression in spinal dorsal horn neurons. Strikingly, both effects are absent in Na(v)1.7 conditional knock-out (cKO) mice. Furthermore, burn injury increases density and shifts activation of tetrodotoxin-sensitive currents in a hyperpolarized direction, both pro-excitatory properties, in DRG neurons from wild-type but not Na(v)1.7 cKO mice. We propose that, in sensory neurons damaged by burn injury to the hindpaw, Na(v)1.7 currents contribute to the hyperexcitability of sensory neurons, their communication with postsynaptic spinal pain pathways, and behavioral thresholds to heat stimuli. Our results offer insights into the molecular and cellular mechanisms of modality-specific pain signaling, and suggest Na(v)1.7-blocking drugs may be effective in burn patients.
Collapse
|
28
|
Pristerà A, Baker MD, Okuse K. Association between tetrodotoxin resistant channels and lipid rafts regulates sensory neuron excitability. PLoS One 2012; 7:e40079. [PMID: 22870192 PMCID: PMC3411591 DOI: 10.1371/journal.pone.0040079] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 06/05/2012] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) play a key role in the initiation and propagation of action potentials in neurons. NaV1.8 is a tetrodotoxin (TTX) resistant VGSC expressed in nociceptors, peripheral small-diameter neurons able to detect noxious stimuli. NaV1.8 underlies the vast majority of sodium currents during action potentials. Many studies have highlighted a key role for NaV1.8 in inflammatory and chronic pain models. Lipid rafts are microdomains of the plasma membrane highly enriched in cholesterol and sphingolipids. Lipid rafts tune the spatial and temporal organisation of proteins and lipids on the plasma membrane. They are thought to act as platforms on the membrane where proteins and lipids can be trafficked, compartmentalised and functionally clustered. In the present study we investigated NaV1.8 sub-cellular localisation and explored the idea that it is associated with lipid rafts in nociceptors. We found that NaV1.8 is distributed in clusters along the axons of DRG neurons in vitro and ex vivo. We also demonstrated, by biochemical and imaging studies, that NaV1.8 is associated with lipid rafts along the sciatic nerve ex vivo and in DRG neurons in vitro. Moreover, treatments with methyl-β-cyclodextrin (MβCD) and 7-ketocholesterol (7KC) led to the dissociation between rafts and NaV1.8. By calcium imaging we demonstrated that the lack of association between rafts and NaV1.8 correlated with impaired neuronal excitability, highlighted by a reduction in the number of neurons able to conduct mechanically- and chemically-evoked depolarisations. These findings reveal the sub-cellular localisation of NaV1.8 in nociceptors and highlight the importance of the association between NaV1.8 and lipid rafts in the control of nociceptor excitability.
Collapse
Affiliation(s)
- Alessandro Pristerà
- Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
| | - Mark D. Baker
- Neuroscience and Trauma Centre, Blizard Institute, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, London, United Kingdom
| | - Kenji Okuse
- Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
- * E-mail:
| |
Collapse
|
29
|
Vasylyev DV, Waxman SG. Membrane properties and electrogenesis in the distal axons of small dorsal root ganglion neurons in vitro. J Neurophysiol 2012; 108:729-40. [DOI: 10.1152/jn.00091.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Although it is generally thought that sensory transduction occurs at or close to peripheral nerve endings, with action potentials subsequently propagating along the axons of dorsal root ganglia (DRG) neurons toward the central nervous system, the small diameter of nociceptive axons and their endings have made it difficult to estimate their membrane properties and electrogenic characteristics. Even the resting potentials of nociceptive axons are unknown. In this study, we developed the capability to record directly with patch-clamp electrodes from the small-diameter distal axons of DRG neurons in vitro. We showed using current-clamp recordings that 1) these sensory axons have a resting potential of −60.2 ± 1 mV; 2) both tetrodotoxin (TTX)-sensitive (TTX-S) and TTX-resistant (TTX-R) Na+ channels are present and available for activation at resting potential, at densities that can support action potential electrogenesis in these axons; 3) TTX-sensitive channels contribute to the amplification of small depolarizations that are subthreshold with respect to the action potential in these axons; 4) TTX-R channels can support the production of action potentials in these axons; and 5) these TTX-R channels can produce repetitive firing, even at depolarized membrane potentials where TTX-S channels are inactivated. Finally, using voltage-clamp recordings with an action potential as the command, we confirmed the presence of both TTX-S and TTX-R channels, which are activated sequentially during action potential in these axons. These results provide direct evidence for the presence of TTX-S and TTX-R Na+ channels that are functionally available at resting potential and contribute to electrogenesis in small-diameter afferent axons.
Collapse
Affiliation(s)
- Dmytro V. Vasylyev
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; and
- Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| |
Collapse
|
30
|
Verkerk AO, Remme CA, Schumacher CA, Scicluna BP, Wolswinkel R, de Jonge B, Bezzina CR, Veldkamp MW. Functional Na
V
1.8 Channels in Intracardiac Neurons. Circ Res 2012; 111:333-43. [DOI: 10.1161/circresaha.112.274035] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rationale:
The
SCN10A
gene encodes the neuronal sodium channel isoform Na
V
1.8. Several recent genome-wide association studies have linked
SCN10A
to PR interval and QRS duration, strongly suggesting an as-yet unknown role for Na
V
1.8 in cardiac electrophysiology.
Objective:
To demonstrate the functional presence of
SCN10A
/Nav1.8 in intracardiac neurons of the mouse heart.
Methods and Results:
Immunohistochemistry on mouse tissue sections showed intense Na
V
1.8 labeling in dorsal root ganglia and intracardiac ganglia and only modest Na
V
1.8 expression within the myocardium. Immunocytochemistry further revealed substantial Na
V
1.8 staining in isolated neurons from murine intracardiac ganglia but no Na
V
1.8 expression in isolated ventricular myocytes. Patch-clamp studies demonstrated that the Na
V
1.8 blocker A-803467 (0.5–2 μmol/L) had no effect on either mean sodium current (I
Na
) density or I
Na
gating kinetics in isolated myocytes but significantly reduced I
Na
density in intracardiac neurons. Furthermore, A-803467 accelerated the slow component of current decay and shifted voltage dependence of inactivation toward more negative voltages, as expected for blockade of Na
V
1.8-based I
Na
. In line with these findings, A-803467 did not affect cardiomyocyte action potential upstroke velocity but markedly reduced action potential firing frequency in intracardiac neurons, confirming a functional role for Na
V
1.8 in cardiac neural activity.
Conclusions:
Our findings demonstrate the functional presence of
SCN10A
/Na
V
1.8 in intracardiac neurons, indicating a novel role for this neuronal sodium channel in regulation of cardiac electric activity.
Collapse
Affiliation(s)
- Arie O. Verkerk
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Carol Ann Remme
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Cees A. Schumacher
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Brendon P. Scicluna
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Rianne Wolswinkel
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Berend de Jonge
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Connie R. Bezzina
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Marieke W. Veldkamp
- From the Department of Clinical and Experimental Cardiology (C.A.R., C.A.S., B.P.S., R.W., C.R.B., M.W.V.) and the Department of Anatomy, Embryology, and Physiology (A.O.V., B.d.J.), Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
31
|
Waxman SG. Sodium channels, the electrogenisome and the electrogenistat: lessons and questions from the clinic. J Physiol 2012; 590:2601-12. [PMID: 22411010 DOI: 10.1113/jphysiol.2012.228460] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In the six decades that have followed the work of Hodgkin and Huxley, multiple generations of neuroscientists and biophysicists have built upon their pivotal contributions. It is now clear that, in mammals, nine genes encode nine distinct voltage-gated sodium channels with different amino acid sequences and different physiological and pharmacological properties. The different sodium channel isoforms produce a multiplicity of distinct sodium currents with different time-dependent characteristics and voltage dependencies, which interact with each other and with the currents produced by other channels (including calcium and potassium channels) to shape neuronal firing patterns. Expression of these sodium channel isoforms is highly dynamic, both in the normal nervous system, and in the injured nervous system. Recent research has shed light on the roles of sodium channels in human disease, a development that may open up new therapeutic strategies. This article examines the pain-signalling system as an example of a neuronal network where multiple sodium channel isoforms play complementary roles in electrogenesis and a strong link with human disease has been established. Recent research suggests that it may be possible to target specific sodium channel isoforms that drive hyperexcitability in pain-signalling neurons, thereby providing new therapeutic strategies for chronic pain, and providing an illustration of the impact of the Hodgkin-Huxley legacy in the clinical domain.
Collapse
Affiliation(s)
- Stephen G Waxman
- Department of Neurology and Centre for Neuroscience & Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA.
| |
Collapse
|
32
|
The chemokine CCL2 increases Nav1.8 sodium channel activity in primary sensory neurons through a Gβγ-dependent mechanism. J Neurosci 2012; 31:18381-90. [PMID: 22171040 DOI: 10.1523/jneurosci.3386-11.2011] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Changes in function of voltage-gated sodium channels in nociceptive primary sensory neurons participate in the development of peripheral hyperexcitability that occurs in neuropathic and inflammatory chronic pain conditions. Among them, the tetrodotoxin-resistant (TTX-R) sodium channel Na(v)1.8, primarily expressed by small- and medium-sized dorsal root ganglion (DRG) neurons, substantially contributes to the upstroke of action potential in these neurons. Compelling evidence also revealed that the chemokine CCL2 plays a critical role in chronic pain facilitation via its binding to CCR2 receptors. In this study, we therefore investigated the effects of CCL2 on the density and kinetic properties of TTX-R Na(v)1.8 currents in acutely small/medium dissociated lumbar DRG neurons from naive adult rats. Whole-cell patch-clamp recordings demonstrated that CCL2 concentration-dependently increased TTX-resistant Na(v)1.8 current densities in both small- and medium-diameter sensory neurons. Incubation with CCL2 also shifted the activation and steady-state inactivation curves of Na(v)1.8 in a hyperpolarizing direction in small sensory neurons. No change in the activation and inactivation kinetics was, however, observed in medium-sized nociceptive neurons. Our electrophysiological recordings also demonstrated that the selective CCR2 antagonist INCB3344 [N-[2-[[(3S,4S)-1-E4-(1,3-benzodioxol-5-yl)-4-hydroxycyclohexyl]-4-ethoxy-3-pyrrolidinyl]amino]-2-oxoethyl]-3-(trifluoromethyl)benzamide] blocks the potentiation of Na(v)1.8 currents by CCL2 in a concentration-dependent manner. Furthermore, the enhancement in Na(v)1.8 currents was prevented by pretreatment with pertussis toxin (PTX) or gallein (a Gβγ inhibitor), indicating the involvement of Gβγ released from PTX-sensitive G(i/o)-proteins in the cross talk between CCR2 and Na(v)1.8. Together, our data clearly demonstrate that CCL2 may excite primary sensory neurons by acting on the biophysical properties of Na(v)1.8 currents via a CCR2/Gβγ-dependent mechanism.
Collapse
|
33
|
The transcription factor Smad-interacting protein 1 controls pain sensitivity via modulation of DRG neuron excitability. Pain 2011; 152:2384-2398. [DOI: 10.1016/j.pain.2011.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 06/20/2011] [Accepted: 07/11/2011] [Indexed: 11/21/2022]
|
34
|
Abstract
Many primary vestibular afferents form large cup-shaped postsynaptic terminals (calyces) that envelope the basolateral surfaces of type I hair cells. The calyceal terminals both respond to glutamate released from ribbon synapses in the type I cells and initiate spikes that propagate to the afferent's central terminals in the brainstem. The combination of synaptic and spike initiation functions in these unique sensory endings distinguishes them from the axonal nodes of central neurons and peripheral nerves, such as the sciatic nerve, which have provided most of our information about nodal specializations. We show that rat vestibular calyces express an unusual mix of voltage-gated Na and K channels and scaffolding, cell adhesion, and extracellular matrix proteins, which may hold the ion channels in place. Protein expression patterns form several microdomains within the calyx membrane: a synaptic domain facing the hair cell, the heminode abutting the first myelinated internode, and one or two intermediate domains. Differences in the expression and localization of proteins between afferent types and zones may contribute to known variations in afferent physiology.
Collapse
|
35
|
Yu YQ, Zhao F, Guan SM, Chen J. Antisense-mediated knockdown of Na(V)1.8, but not Na(V)1.9, generates inhibitory effects on complete Freund's adjuvant-induced inflammatory pain in rat. PLoS One 2011; 6:e19865. [PMID: 21572961 PMCID: PMC3091880 DOI: 10.1371/journal.pone.0019865] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 04/12/2011] [Indexed: 02/01/2023] Open
Abstract
Tetrodotoxin-resistant (TTX-R) sodium channels NaV1.8 and NaV1.9 in sensory neurons were known as key pain modulators. Comparing with the widely reported NaV1.8, roles of NaV1.9 on inflammatory pain are poorly studied by antisense-induced specific gene knockdown. Here, we used molecular, electrophysiological and behavioral methods to examine the effects of antisense oligodeoxynucleotide (AS ODN) targeting NaV1.8 and NaV1.9 on inflammatory pain. Following complete Freund's adjuvant (CFA) inflammation treatment, NaV1.8 and NaV1.9 in rat dorsal root ganglion (DRG) up-regulated mRNA and protein expressions and increased sodium current densities. Immunohistochemical data demonstrated that NaV1.8 mainly localized in medium and small-sized DRG neurons, whereas NaV1.9 only expressed in small-sized DRG neurons. Intrathecal (i.t.) delivery of AS ODN was used to down-regulate NaV1.8 or NaV1.9 expressions confirmed by immunohistochemistry and western blot. Unexpectedly, behavioral tests showed that only NaV1.8 AS ODN, but not NaV1.9 AS ODN could reverse CFA-induced heat and mechanical hypersensitivity. Our data indicated that TTX-R sodium channels NaV1.8 and NaV1.9 in primary sensory neurons played distinct roles in CFA-induced inflammatory pain and suggested that antisense oligodeoxynucleotide-mediated blocking of key pain modulator might point toward a potential treatment strategy against certain types of inflammatory pain.
Collapse
Affiliation(s)
- Yao-Qing Yu
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, the Fourth Military Medical University, Xi'an, People's Republic of China
| | - Feng Zhao
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, the Fourth Military Medical University, Xi'an, People's Republic of China
| | - Su-Min Guan
- School of Stomatology, the Fourth Military Medical University, Xi'an, People's Republic of China
- * E-mail: (JC); (SG)
| | - Jun Chen
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, the Fourth Military Medical University, Xi'an, People's Republic of China
- Institute for Biomedical Sciences of Pain, Capital Medical University, Beijing, People's Republic of China
- * E-mail: (JC); (SG)
| |
Collapse
|
36
|
Swanwick RS, Pristerá A, Okuse K. The trafficking of Na(V)1.8. Neurosci Lett 2010; 486:78-83. [PMID: 20816723 PMCID: PMC2977848 DOI: 10.1016/j.neulet.2010.08.074] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/24/2010] [Accepted: 08/25/2010] [Indexed: 12/23/2022]
Abstract
The α-subunit of tetrodotoxin-resistant voltage-gated sodium channel Na(V)1.8 is selectively expressed in sensory neurons. It has been reported that Na(V)1.8 is involved in the transmission of nociceptive information from sensory neurons to the central nervous system in nociceptive [1] and neuropathic [24] pain conditions. Thus Na(V)1.8 has been a promising target to treat chronic pain. Here we discuss the recent advances in the study of trafficking mechanism of Na(V)1.8. These pieces of information are particularly important as such trafficking machinery could be new targets for painkillers.
Collapse
Affiliation(s)
| | | | - Kenji Okuse
- Division of Cell & Molecular Biology, Imperial College London, London SW7 2AZ, UK
| |
Collapse
|
37
|
Dib-Hajj SD, Waxman SG. Isoform-specific and pan-channel partners regulate trafficking and plasma membrane stability; and alter sodium channel gating properties. Neurosci Lett 2010; 486:84-91. [DOI: 10.1016/j.neulet.2010.08.077] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 08/25/2010] [Accepted: 08/26/2010] [Indexed: 12/19/2022]
|
38
|
Miranda-Morales M, Ochoa-Cortes F, Stern E, Lomax AE, Vanner S. Axon Reflexes Evoked by Transient Receptor Potential Vanilloid 1 Activation Are Mediated by Tetrodotoxin-Resistant Voltage-Gated Na+ Channels in Intestinal Afferent Nerves. J Pharmacol Exp Ther 2010; 334:566-75. [DOI: 10.1124/jpet.110.165969] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
39
|
Abstract
Nociception is essential for survival whereas pathological pain is maladaptive and often unresponsive to pharmacotherapy. Voltage-gated sodium channels, Na(v)1.1-Na(v)1.9, are essential for generation and conduction of electrical impulses in excitable cells. Human and animal studies have identified several channels as pivotal for signal transmission along the pain axis, including Na(v)1.3, Na(v)1.7, Na(v)1.8, and Na(v)1.9, with the latter three preferentially expressed in peripheral sensory neurons and Na(v)1.3 being upregulated along pain-signaling pathways after nervous system injuries. Na(v)1.7 is of special interest because it has been linked to a spectrum of inherited human pain disorders. Here we review the contribution of these sodium channel isoforms to pain.
Collapse
Affiliation(s)
- Sulayman D Dib-Hajj
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | | | | | | |
Collapse
|
40
|
Wimmer VC, Reid CA, So EYW, Berkovic SF, Petrou S. Axon initial segment dysfunction in epilepsy. J Physiol 2010; 588:1829-40. [PMID: 20375142 DOI: 10.1113/jphysiol.2010.188417] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The axon initial segment (AIS) contains the site of action potential initiation and plays a major role in neuronal excitability. AIS function relies on high concentrations of different ion channels and complex regulatory mechanisms that orchestrate molecular microarchitecture. We review recent evidence that a large number of ion channels associated with epilepsy are enriched at the AIS, making it a 'hotspot' for epileptogenesis. Furthermore, we present novel data on the clustering of GABRgamma2 receptors in the AIS of cortical and hippocampal neurons in a knock in mouse model of a human genetic epilepsy. This article highlights the molecular coincidence of epilepsy mutations at the AIS and reviews pathogenic mechanisms converging at the AIS.
Collapse
Affiliation(s)
- Verena C Wimmer
- Florey Neuroscience Institutes, University of Melbourne, Parkville 3010, Victoria, Australia
| | | | | | | | | |
Collapse
|
41
|
Obreja O, Schmelz M. Single-fiber recordings of unmyelinated afferents in pig. Neurosci Lett 2010; 470:175-9. [DOI: 10.1016/j.neulet.2009.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 10/01/2009] [Accepted: 10/02/2009] [Indexed: 11/28/2022]
|
42
|
Liu C, Li Q, Su Y, Bao L. Prostaglandin E2 promotes Na1.8 trafficking via its intracellular RRR motif through the protein kinase A pathway. Traffic 2009; 11:405-17. [PMID: 20028484 DOI: 10.1111/j.1600-0854.2009.01027.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Voltage-gated sodium channels (Na(v)) are essential for the initiation and propagation of action potentials in neurons. Na(v)1.8 activity is regulated by prostaglandin E(2) (PGE(2)). There is, however, no direct evidence showing the regulated trafficking of Na(v)1.8, and the molecular and cellular mechanism of PGE(2)-induced sodium channel trafficking is not clear. Here, we report that PGE(2) regulates the trafficking of Na(v)1.8 through the protein kinase A (PKA) signaling pathway, and an RRR motif in the first intracellular loop of Na(v)1.8 mediates this effect. In rat dorsal root ganglion (DRG) neurons, prolonged PGE(2) treatment enhanced Na(v)1.8 currents by increasing the channel density on the cell surface. Activation of PKA by forskolin had the same effect on DRG neurons and human embryonic kidney 293T cells expressing Na(v)1.8. Inhibition of PKA completely blocked the PGE(2)-promoted effect on Na(v)1.8. Mutation of five PKA phosphorylation sites or the RRR motif in the first intracellular loop of Na(v)1.8 abolished the PKA-promoted Na(v)1.8 surface expression. Furthermore, a membrane-tethered peptide containing the intracellular RRR motif disrupted the PGE(2)-induced promotion of the Na(v)1.8 current in DRG neurons. Our data indicate that PGE(2) promotes the surface expression of Na(v)1.8 via an intracellular RRR motif, and provide a novel mechanism for functional modulation of Na(v)1.8 by hyperalgesic agents.
Collapse
Affiliation(s)
- Chao Liu
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
| | | | | | | |
Collapse
|
43
|
Persson AK, Thun J, Xu XJ, Wiesenfeld-Hallin Z, Ström M, Devor M, Lidman O, Fried K. Autotomy behavior correlates with the DRG and spinal expression of sodium channels in inbred mouse strains. Brain Res 2009; 1285:1-13. [DOI: 10.1016/j.brainres.2009.06.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 05/20/2009] [Accepted: 06/03/2009] [Indexed: 12/20/2022]
|
44
|
Cang CL, Zhang H, Zhang YQ, Zhao ZQ. PKCepsilon-dependent potentiation of TTX-resistant Nav1.8 current by neurokinin-1 receptor activation in rat dorsal root ganglion neurons. Mol Pain 2009; 5:33. [PMID: 19563686 PMCID: PMC2715383 DOI: 10.1186/1744-8069-5-33] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 06/30/2009] [Indexed: 11/15/2022] Open
Abstract
Background Substance P (SP), which mainly exists in a subtype of small-diameter dorsal root ganglion (DRG) neurons, is an important signal molecule in pain processing in the spinal cord. Our previous results have proved the expression of SP receptor neurokinin-1 (NK-1) on DRG neurons and its interaction with transient receptor potential vanilloid 1 (TRPV1) receptor. Results In this study we investigated the effect of NK-1 receptor agonist on Nav1.8, a tetrodotoxin (TTX)-resistant sodium channel, in rat small-diameter DRG neurons employing whole-cell patch clamp recordings. NK-1 agonist [Sar9, Met(O2)11]-substance P (Sar-SP) significantly enhanced the Nav1.8 currents in a subgroup of small-diameter DRG neurons under both the normal and inflammatory situation, and the enhancement was blocked by NK-1 antagonist Win51708 and protein kinase C (PKC) inhibitor bisindolylmaleimide (BIM), but not the protein kinase A (PKA) inhibitor H89. In particular, the inhibitor of PKCε, a PKC isoform, completely blocked this effect. Under current clamp model, Sar-SP reduced the amount of current required to evoke action potentials and increased the firing rate in a subgroup of DRG neurons. Conclusion These data suggest that activation of NK-1 receptor potentiates Nav1.8 sodium current via PKCε-dependent signaling pathway, probably participating in the generation of inflammatory hyperalgesia.
Collapse
Affiliation(s)
- Chun-Lei Cang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, PR China.
| | | | | | | |
Collapse
|
45
|
Yang RH, Strong JA, Zhang JM. NF-kappaB mediated enhancement of potassium currents by the chemokine CXCL1/growth related oncogene in small diameter rat sensory neurons. Mol Pain 2009; 5:26. [PMID: 19476648 PMCID: PMC2698898 DOI: 10.1186/1744-8069-5-26] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 05/28/2009] [Indexed: 01/24/2023] Open
Abstract
Background Inflammatory processes play important roles in both neuropathic and inflammatory pain states, but the effects of inflammation per se within the sensory ganglia are not well understood. The cytokine growth-related oncogene (GRO/KC; CXCL1) shows strong, rapid upregulation in dorsal root ganglion (DRG) in both nerve injury and inflammatory pain models. We examined the direct effects of GRO/KC on small diameter DRG neurons, which are predominantly nociceptive. Whole cell voltage clamp technique was used to measure voltage-activated potassium (K) currents in acutely cultured adult rat small diameter sensory neurons. Fluorescently labeled isolectin B4 (IB4) was used to classify cells as IB4-positive or IB4-negative. Results In IB4-negative neurons, voltage-activated K current densities of both transient and sustained components were increased after overnight incubation with GRO/KC (1.5 nM), without marked changes in voltage dependence or kinetics. The average values for the slow and fast decay time constants at 20 mV were unchanged by GRO/KC. The amplitude of the fast inactivating component increased significantly with no large shifts in the voltage dependence of inactivation. The increase in K currents was completely blocked by co-incubation with protein synthesis inhibitor cycloheximide (CHX) or NF-κB inhibitors pyrrolidine dithiocarbamate (PDTC) or quinazoline (6-Amino-4-(4-phenoxypheny lethylamino;QNZ). In contrast, the voltage-activated K current of IB4-positive neurons was unchanged by GRO/KC. GRO/KC incubation caused no significant changes in the expression level of eight selected voltage-gated K channel genes in quantitative PCR analysis. Conclusion The results suggest that GRO/KC has important effects in inflammatory processes via its direct actions on sensory neurons, and that activation of NF-κB is involved in the GRO/KC-induced enhancement of K currents.
Collapse
Affiliation(s)
- Rui-Hua Yang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0531, USA.
| | | | | |
Collapse
|
46
|
Dib-Hajj SD, Binshtok AM, Cummins TR, Jarvis MF, Samad T, Zimmermann K. Voltage-gated sodium channels in pain states: Role in pathophysiology and targets for treatment. ACTA ACUST UNITED AC 2009; 60:65-83. [DOI: 10.1016/j.brainresrev.2008.12.005] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2008] [Indexed: 12/19/2022]
|
47
|
Compton AG, Albrecht DE, Seto JT, Cooper ST, Ilkovski B, Jones KJ, Challis D, Mowat D, Ranscht B, Bahlo M, Froehner SC, North KN. Mutations in contactin-1, a neural adhesion and neuromuscular junction protein, cause a familial form of lethal congenital myopathy. Am J Hum Genet 2008; 83:714-24. [PMID: 19026398 DOI: 10.1016/j.ajhg.2008.10.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/16/2008] [Accepted: 10/29/2008] [Indexed: 01/06/2023] Open
Abstract
We have previously reported a group of patients with congenital onset weakness associated with a deficiency of members of the syntrophin-alpha-dystrobrevin subcomplex and have demonstrated that loss of syntrophin and dystrobrevin from the sarcolemma of skeletal muscle can also be associated with denervation. Here, we have further studied four individuals from a consanguineous Egyptian family with a lethal congenital myopathy inherited in an autosomal-recessive fashion and characterized by a secondary loss of beta2-syntrophin and alpha-dystrobrevin from the muscle sarcolemma, central nervous system involvement, and fetal akinesia. We performed homozygosity mapping and candidate gene analysis and identified a mutation that segregates with disease within CNTN1, the gene encoding for the neural immunoglobulin family adhesion molecule, contactin-1. Contactin-1 transcripts were markedly decreased on gene-expression arrays of muscle from affected family members compared to controls. We demonstrate that contactin-1 is expressed at the neuromuscular junction (NMJ) in mice and man in addition to the previously documented expression in the central and peripheral nervous system. In patients with secondary dystroglycanopathies, we show that contactin-1 is abnormally localized to the sarcolemma instead of exclusively at the NMJ. The cntn1 null mouse presents with ataxia, progressive muscle weakness, and postnatal lethality, similar to the affected members in this family. We propose that loss of contactin-1 from the NMJ impairs communication or adhesion between nerve and muscle resulting in the severe myopathic phenotype. This disorder is part of the continuum in the clinical spectrum of congenital myopathies and congenital myasthenic syndromes.
Collapse
Affiliation(s)
- Alison G Compton
- Institute for Neuromuscular Research, The Children's Hospital at Westmead, NSW, Australia
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Zhang ZN, Li Q, Liu C, Wang HB, Wang Q, Bao L. The voltage-gated Na+ channel Nav1.8 contains an ER-retention/retrieval signal antagonized by the β3 subunit. J Cell Sci 2008; 121:3243-52. [DOI: 10.1242/jcs.026856] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Voltage-gated Na+ channel (Nav) 1.8 contributes to the majority of the Na+ current that underlies the depolarizing phase of action potentials. Nav1.8 is mainly distributed intracellularly and its current amplitude can be enhanced by the β3 subunit. However, little is known about the mechanisms underlying its intracellular retention and the effects mediated by the β3 subunit. Here, we show that the β3 subunit promotes surface expression of Nav1.8 by masking its endoplasmic reticulum (ER)-retention/retrieval signal. The RRR motif in the first intracellular loop of Nav1.8 is responsible for retaining Nav1.8 in the ER and restricting its surface expression. The β3 subunit facilitates surface expression of Nav1.8. The intracellular C-terminus of the β3 subunit interacts with the first intracellular loop of Nav1.8 and masks the ER-retention/retrieval signal. Mutation of the RRR motif results in a significant increase in surface expression of Nav1.8 and abolishes the β3-subunit-mediated effects. Thus, the β3 subunit regulates surface expression of Nav1.8 by antagonizing its ER-retention/retrieval signal. These results reveal a novel mechanism for the effect of the Na+ channel β subunits on the α subunits.
Collapse
Affiliation(s)
- Zhen-Ning Zhang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Qian Li
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Chao Liu
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Hai-Bo Wang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Qiong Wang
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
| | - Lan Bao
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
| |
Collapse
|
49
|
Wang JG, Strong JA, Xie W, Yang RH, Coyle DE, Wick DM, Dorsey ED, Zhang JM. The chemokine CXCL1/growth related oncogene increases sodium currents and neuronal excitability in small diameter sensory neurons. Mol Pain 2008; 4:38. [PMID: 18816377 PMCID: PMC2562993 DOI: 10.1186/1744-8069-4-38] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 09/24/2008] [Indexed: 11/10/2022] Open
Abstract
Background Altered Na+ channel expression, enhanced excitability, and spontaneous activity occur in nerve-injury and inflammatory models of pathological pain, through poorly understood mechanisms. The cytokine GRO/KC (growth related oncogene; CXCL1) shows strong, rapid upregulation in dorsal root ganglion in both nerve injury and inflammatory models. Neurons and glia express its receptor (CXCR2). CXCL1 has well-known effects on immune cells, but little is known about its direct effects on neurons. Results We report that GRO/KC incubation (1.5 nM, overnight) caused marked upregulation of Na+ currents in acutely isolated small diameter rat (adult) sensory neurons in vitro. In both IB4-positive and IB4-negative sensory neurons, TTX-resistant and TTX-sensitive currents increased 2- to 4 fold, without altered voltage dependence or kinetic changes. These effects required long exposures, and were completely blocked by co-incubation with protein synthesis inhibitor cycloheximide. Amplification of cDNA from the neuronal cultures showed that 3 Na channel isoforms were predominant both before and after GRO/KC treatment (Nav 1.1, 1.7, and 1.8). TTX-sensitive isoforms 1.1 and 1.7 significantly increased 2 – 3 fold after GRO/KC incubation, while 1.8 showed a trend towards increased expression. Current clamp experiments showed that GRO/KC caused a marked increase in excitability, including resting potential depolarization, decreased rheobase, and lower action potential threshold. Neurons acquired a striking ability to fire repetitively; IB4-positive cells also showed marked broadening of action potentials. Immunohistochemical labelling confirmed that the CXCR2 receptor was present in most neurons both in dissociated cells and in DRG sections, as previously shown for neurons in the CNS. Conclusion Many studies on the role of chemokines in pain conditions have focused on their rapid and indirect effects on neurons, via release of inflammatory mediators from immune and glial cells. Our study suggests that GRO/KC may also have important pro-nociceptive effects via its direct actions on sensory neurons, and may induce long-term changes that involve protein synthesis.
Collapse
Affiliation(s)
- Jun-Gang Wang
- Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0531, USA.
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Wasner U, Geist B, Battefeld A, Bauer P, Müller J, Rolfs A, Strauss U. Specific properties of sodium currents in multipotent striatal progenitor cells. Eur J Neurosci 2008; 28:1068-79. [DOI: 10.1111/j.1460-9568.2008.06427.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|