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Wimalasena NK, Taub DG, Shim J, Hakim S, Kawaguchi R, Chen L, El-Rifai M, Geschwind D, Dib-Hajj SD, Waxman SG, Woolf CJ. Na v1.7 gain-of-function mutation I228M triggers age-dependent nociceptive insensitivity and C-LTMR dysregulation. Exp Neurol 2023; 364:114393. [PMID: 37003485 PMCID: PMC10171359 DOI: 10.1016/j.expneurol.2023.114393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/09/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
Gain-of-function mutations in Scn9a, which encodes the peripheral sensory neuron-enriched voltage-gated sodium channel Nav1.7, cause paroxysmal extreme pain disorder (PEPD), inherited erythromelalgia (IEM), and small fiber neuropathy (SFN). Conversely, loss-of-function mutations in the gene are linked to congenital insensitivity to pain (CIP). These mutations are evidence for a link between altered sodium conductance and neuronal excitability leading to somatosensory aberrations, pain, or its loss. Our previous work in young adult mice with the Nav1.7 gain-of-function mutation, I228M, showed the expected DRG neuron hyperexcitability, but unexpectedly the mice had normal mechanical and thermal behavioral sensitivity. We now show that with aging both male and female mice with this mutation unexpectedly develop a profound insensitivity to noxious heat and cold, as well skin lesions that span the body. Electrophysiology demonstrates that, in contrast to young mice, aged I228M mouse DRGs have a profound loss of sodium conductance and changes in activation and slow inactivation dynamics, representing a loss-of-function. Through RNA sequencing we explored how these age-related changes may produce the phenotypic changes and found a striking and specific decrease in C-low threshold mechanoreceptor- (cLTMR) associated gene expression, suggesting a potential contribution of this DRG neuron subtype to Nav1.7 dysfunction phenotypes. A GOF mutation in a voltage-gated channel can therefore produce over a prolonged time, highly complex and unexpected alterations in the nervous system beyond excitability changes.
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Affiliation(s)
- Nivanthika K Wimalasena
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Daniel G Taub
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jaehoon Shim
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Sara Hakim
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Riki Kawaguchi
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Lubin Chen
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA; Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Mahmoud El-Rifai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Dan Geschwind
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sulayman D Dib-Hajj
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA; Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA; Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT 06516, USA
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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Bohic M, Marics I, Santos C, Malapert P, Ben-Arie N, Salio C, Reynders A, Le Feuvre Y, Saurin AJ, Moqrich A. Loss of bhlha9 Impairs Thermotaxis and Formalin-Evoked Pain in a Sexually Dimorphic Manner. Cell Rep 2020; 30:602-610.e6. [PMID: 31968239 DOI: 10.1016/j.celrep.2019.12.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 11/18/2019] [Accepted: 12/12/2019] [Indexed: 01/07/2023] Open
Abstract
C-LTMRs are known to convey affective aspects of touch and to modulate injury-induced pain in humans and mice. However, a role for these neurons in temperature sensation has been suggested, but not fully demonstrated. Here, we report that deletion of C-low-threshold mechanoreceptor (C-LTMR)-expressed bhlha9 causes impaired thermotaxis behavior and exacerbated formalin-evoked pain in male, but not female, mice. Positive modulators of GABAA receptors failed to relieve inflammatory formalin pain and failed to decrease the frequency of spontaneous excitatory post-synaptic currents (sEPSCs) selectively in bhlha9 knockout (KO) males. This could be explained by a drastic change in the GABA content of lamina II inner inhibitory interneurons contacting C-LTMR central terminals. Finally, C-LTMR-specific deep RNA sequencing revealed more genes differentially expressed in male than in female bhlha9 KO C-LTMRs. Our data consolidate the role of C-LTMRs in modulation of formalin pain and provide in vivo evidence of their role in the discriminative aspects of temperature sensation.
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Salio C, Aimar P, Malapert P, Moqrich A, Merighi A. Neurochemical and Ultrastructural Characterization of Unmyelinated Non-peptidergic C-Nociceptors and C-Low Threshold Mechanoreceptors Projecting to Lamina II of the Mouse Spinal Cord. Cell Mol Neurobiol 2021; 41:247-62. [PMID: 32306148 DOI: 10.1007/s10571-020-00847-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/09/2020] [Indexed: 12/19/2022]
Abstract
C-nociceptors (C-Ncs) and non-nociceptive C-low threshold mechanoreceptors (C-LTMRs) are two subpopulations of small unmyelinated non-peptidergic C-type neurons of the dorsal root ganglia (DRGs) with central projections displaying a specific pattern of termination in the spinal cord dorsal horn. Although these two subpopulations exist in several animals, remarkable neurochemical differences occur between mammals, particularly rat/humans from one side and mouse from the other. Mouse is widely investigated by transcriptomics. Therefore, we here studied the immunocytochemistry of murine C-type DRG neurons and their central terminals in spinal lamina II at light and electron microscopic levels. We used a panel of markers for peptidergic (CGRP), non-peptidergic (IB4), nociceptive (TRPV1), non-nociceptive (VGLUT3) C-type neurons and two strains of transgenic mice: the TAFA4Venus knock-in mouse to localize the TAFA4+ C-LTMRs, and a genetically engineered ginip mouse that allows an inducible and tissue-specific ablation of the DRG neurons expressing GINIP, a key modulator of GABABR-mediated analgesia. We confirmed that IB4 and TAFA4 did not coexist in small non-peptidergic C-type DRG neurons and separately tagged the C-Ncs and the C-LTMRs. We then showed that TRPV1 was expressed in only about 7% of the IB4+ non-peptidergic C-Ncs and their type Ia glomerular terminals within lamina II. Notably, the selective ablation of GINIP did not affect these neurons, whereas it reduced IB4 labeling in the medial part of lamina II and the density of C-LTMRs glomerular terminals to about one half throughout the entire lamina. We discuss the significance of these findings for interspecies differences and functional relevance.
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Reynders A, Moqrich A. Analysis of cutaneous MRGPRD free nerve endings and C-LTMRs transcriptomes by RNA-sequencing. Genom Data 2015; 5:132-5. [PMID: 26484241 PMCID: PMC4583636 DOI: 10.1016/j.gdata.2015.05.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 05/24/2015] [Indexed: 12/19/2022]
Abstract
The skin is the largest sensory organ that is densely innervated by highly specialized sensory neurons allowing the detection of a wide range of stimulations including light touch, temperature, itch and pain. Our knowledge of the sets of genes instructing the functional specialization of sensory neurons is just emerging. In a previous study, we have identified a new Gαi inhibitory interacting protein (GINIP) that marks two distinct subsets of skin-innervating sensory neurons conveying noxious and pleasant touch: the MRGPRD-expressing C-fibers specialized in noxious touch and the TH+/TAFA4+/V-GLUT3+ C-Low Threshold MechanoReceptors (C-LTMRs), part of neurons processing pleasant touch. In the recent study published by Reynders et al. (2015), we took advantage of GINIPmCherry mouse model in combination with Isolectin B4 (IB4) cell surface labeling and fluorescence activated cell sorting (FACS). We successfully purified MRGPRD+, C-LTMRs and a heterogeneous population of sensory neurons and subjected their RNA contents RNA-deep sequencing (RNA-seq). The subsequent RNA-seq experiment led to the generation of unique sets of data representative of pure transcriptome profiles of each subset. As a result of this pioneering approach, we established the combinatorial expression of the sets of genes that could dictate the functional specializations of MRGPRD+ neurons and C-LTMRs. Herein we provide details regarding the experimental design, the quality controls and statistical analysis of the data deposited at Gene Expression Omnibus under the accession number GSE64091.
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Affiliation(s)
- Ana Reynders
- Aix-Marseille-Université, CNRS, Institut de Biologie du Développement de Marseille, UMR 7288, case 907, 13288 Marseille Cedex 09, France
| | - Aziz Moqrich
- Aix-Marseille-Université, CNRS, Institut de Biologie du Développement de Marseille, UMR 7288, case 907, 13288 Marseille Cedex 09, France
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