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Desiderio S, Schwaller F, Tartour K, Padmanabhan K, Lewin GR, Carroll P, Marmigere F. Touch receptor end-organ innervation and function require sensory neuron expression of the transcription factor Meis2. eLife 2024; 12:RP89287. [PMID: 38386003 PMCID: PMC10942617 DOI: 10.7554/elife.89287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024] Open
Abstract
Touch sensation is primarily encoded by mechanoreceptors, called low-threshold mechanoreceptors (LTMRs), with their cell bodies in the dorsal root ganglia. Because of their great diversity in terms of molecular signature, terminal endings morphology, and electrophysiological properties, mirroring the complexity of tactile experience, LTMRs are a model of choice to study the molecular cues differentially controlling neuronal diversification. While the transcriptional codes that define different LTMR subtypes have been extensively studied, the molecular players that participate in their late maturation and in particular in the striking diversity of their end-organ morphological specialization are largely unknown. Here we identified the TALE homeodomain transcription factor Meis2 as a key regulator of LTMRs target-field innervation in mice. Meis2 is specifically expressed in cutaneous LTMRs, and its expression depends on target-derived signals. While LTMRs lacking Meis2 survived and are normally specified, their end-organ innervations, electrophysiological properties, and transcriptome are differentially and markedly affected, resulting in impaired sensory-evoked behavioral responses. These data establish Meis2 as a major transcriptional regulator controlling the orderly formation of sensory neurons innervating peripheral end organs required for light touch.
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Affiliation(s)
- Simon Desiderio
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM U 1298MontpellierFrance
| | - Frederick Schwaller
- Department of Neuroscience, Max‐Delbrück Centre for Molecular MedicineBerlin‐BuchGermany
| | | | | | - Gary R Lewin
- Department of Neuroscience, Max‐Delbrück Centre for Molecular MedicineBerlin‐BuchGermany
| | - Patrick Carroll
- Institute for Neurosciences of Montpellier, University of Montpellier, INSERM U 1298MontpellierFrance
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2
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Bataille-Savattier A, Le Gall-Ianotto C, Lebonvallet N, Misery L, Talagas M. Do Merkel complexes initiate mechanical itch? Exp Dermatol 2023; 32:226-234. [PMID: 36208286 DOI: 10.1111/exd.14685] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/12/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022]
Abstract
Itch is a common sensation which is amenable to disabling patients' life under pathological and chronic conditions. Shared assertion easily limits itch to chemical itch, without considering mechanical itch and alloknesis, its pathological counterpart. However, in recent years, our understanding of the mechanical itch pathway, particularly in the central nervous system, has been enhanced. In addition, Merkel complexes, conventionally considered as tactile end organs only responsible for light touch perception due to Piezo2 expressed by both Merkel cells and SA1 Aβ-fibres - low threshold mechanical receptors (LTMRs) -, have recently been identified as modulators of mechanical itch. However, the tactile end organs responsible for initiating mechanical itch remain unexplored. The consensus is that some LTMRs, either SA1 Aβ- or A∂- and C-, are cutaneous initiators of mechanical itch, even though they are not self-sufficient to finely detect and encode light mechanical stimuli into sensory perceptions, which depend on the entire hosting tactile end organ. Consequently, to enlighten our understanding of mechanical itch initiation, this article discusses the opportunity to consider Merkel complexes as potential tactile end organs responsible for initiating mechanical itch, under both healthy and pathological conditions. Their unsuspected modulatory abilities indeed show that they are tuned to detect and encode light mechanical stimuli leading to mechanical itch, especially as they host not only SA1 Aβ-LTMRs but also A∂- and C-fibres.
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Affiliation(s)
| | | | | | - Laurent Misery
- University of Brest, LIEN, Brest, France.,CHU Brest, Department of Dermatology, Brest, France
| | - Matthieu Talagas
- University of Brest, LIEN, Brest, France.,CHU Brest, Department of Dermatology, Brest, France
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3
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de Nooij JC. Influencers in the Somatosensory System: Extrinsic Control of Sensory Neuron Phenotypes. Neuroscientist 2022:10738584221074350. [DOI: 10.1177/10738584221074350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Somatosensory neurons in dorsal root ganglia (DRG) comprise several main subclasses: high threshold nociceptors/thermoceptors, high- and low-threshold mechanoreceptors, and proprioceptors. Recent years have seen an explosion in the identification of molecules that underlie the functional diversity of these sensory modalities. They also have begun to reveal the developmental mechanisms that channel the emergence of this subtype diversity, solidifying the importance of peripheral instructive signals. Somatic sensory neurons collectively serve numerous essential physiological and protective roles, and as such, an increased understanding of the processes that underlie the specialization of these sensory subtypes is not only biologically interesting but also clinically relevant.
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4
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Chachar S, Chen J, Qin Y, Wu X, Yu H, Zhou Q, Fan X, Wang C, Brownell I, Xiao Y. Reciprocal signals between nerve and epithelium: how do neurons talk with epithelial cells? AMERICAN JOURNAL OF STEM CELLS 2021; 10:56-67. [PMID: 34849302 PMCID: PMC8610808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/22/2021] [Indexed: 06/13/2023]
Abstract
Most epithelium tissues continuously undergo self-renewal through proliferation and differentiation of epithelial stem cells (known as homeostasis), within a specialized stem cell niche. In highly innervated epithelium, peripheral nerves compose perineural niche and support stem cell homeostasis by releasing a variety of neurotransmitters, hormones, and growth factors and supplying trophic factors to the stem cells. Emerging evidence has shown that both sensory and motor nerves can regulate the fate of epithelial stem cells, thus influencing epithelium homeostasis. Understanding the mechanism of crosstalk between epithelial stem cells and neurons will reveal the important role of the perineural niche in physiological and pathological conditions. Herein, we review recent discoveries of the perineural niche in epithelium mainly in tissue homeostasis, with a limited touch in wound repair and pathogenesis.
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Affiliation(s)
- Sadaruddin Chachar
- Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang UniversityHangzhou 310020, Zhejiang, China
- Department of Biotechnology, Faculty of Crop Production, Sindh Agriculture UniversityTandojam 70060, Pakistan
| | - Jing Chen
- Department of Breast Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang UniversityHangzhou 310016, Zhejiang, China
- Zhejiang University-University of Edinburgh Institute, International Campus, Zhejiang UniversityHaining 314400, Zhejiang, China
| | - Yumei Qin
- School of Food Science and Bioengineering, Zhejiang Gongshang UniversityHangzhou 310018, Zhejiang, China
| | - Xia Wu
- Department of Dermatology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang UniversityHangzhou 310020, Zhejiang, China
| | - Haiyan Yu
- Department of Dermatology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang UniversityHangzhou 310020, Zhejiang, China
| | - Qiang Zhou
- Department of Dermatology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang UniversityHangzhou 310020, Zhejiang, China
| | - Xiaojiao Fan
- School of Pharmacy, Jiangsu UniversityZhenjiang, Jiangsu, China
| | - Chaochen Wang
- Department of Breast Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang UniversityHangzhou 310016, Zhejiang, China
- Zhejiang University-University of Edinburgh Institute, International Campus, Zhejiang UniversityHaining 314400, Zhejiang, China
| | - Isaac Brownell
- Dermatology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesda 20892, Maryland, USA
| | - Ying Xiao
- Central Lab of Biomedical Research Center, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang UniversityHangzhou 310020, Zhejiang, China
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5
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Nguyen MB, Valdes VJ, Cohen I, Pothula V, Zhao D, Zheng D, Ezhkova E. Dissection of Merkel cell formation in hairy and glabrous skin reveals a common requirement for FGFR2-mediated signalling. Exp Dermatol 2019; 28:374-382. [PMID: 30758073 DOI: 10.1111/exd.13901] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 02/04/2019] [Accepted: 02/05/2019] [Indexed: 12/30/2022]
Abstract
Merkel cells are mechanosensory cells involved in tactile discrimination. Merkel cells have been primarily studied in the murine back skin, where they are found in specialized structures called touch domes located around primary hair follicles. Yet, little is known about the morphogenesis of Merkel cells in areas of the skin devoid of hair, such as the glabrous paw skin. Here, we describe Merkel cell formation in the glabrous paw skin during embryogenesis. We first found in the glabrous paw skin that Merkel cells were specified at E15.5, 24 hours later, compared to in the back skin. Additionally, by performing lineage-tracing experiments, we found that unlike in the back skin, SOX9(+) cells do not give rise to Merkel cells in the glabrous paw skin. Finally, we compared the transcriptomes of Merkel cells in the back and the glabrous paw skin and showed that they are similar. Genetic and transcriptome studies showed that the formation of Merkel cells in both regions was controlled by similar regulators. Among them was FGFR2, an upstream factor of MAPK signalling that was reported to have a critical function in Merkel cell formation in the back skin. Here, we showed that FGFR2 is also required for Merkel cell development in the glabrous paw skin. Taken together, our results demonstrate that Merkel cells in the murine back skin and glabrous paw skin are similar, and even though their formation is controlled by a common genetic programme, their precursor cells might differ.
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Affiliation(s)
- Minh Binh Nguyen
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, The Tisch Cancer Institute, New York City, New York.,Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Victor Julian Valdes
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, The Tisch Cancer Institute, New York City, New York.,Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Idan Cohen
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, The Tisch Cancer Institute, New York City, New York.,Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Venu Pothula
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, The Tisch Cancer Institute, New York City, New York.,Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Dejian Zhao
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York
| | - Deyou Zheng
- Departments of Genetics, Neurology, and Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Elena Ezhkova
- Department of Cell, Developmental, and Regenerative Biology, Black Family Stem Cell Institute, The Tisch Cancer Institute, New York City, New York.,Icahn School of Medicine at Mount Sinai, New York City, New York
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6
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Jenkins BA, Fontecilla NM, Lu CP, Fuchs E, Lumpkin EA. The cellular basis of mechanosensory Merkel-cell innervation during development. eLife 2019; 8:42633. [PMID: 30794158 PMCID: PMC6386521 DOI: 10.7554/elife.42633] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/06/2019] [Indexed: 02/06/2023] Open
Abstract
Touch sensation is initiated by mechanosensory neurons that innervate distinct skin structures; however, little is known about how these neurons are patterned during mammalian skin development. We explored the cellular basis of touch-receptor patterning in mouse touch domes, which contain mechanosensory Merkel cell-neurite complexes and abut primary hair follicles. At embryonic stage 16.5 (E16.5), touch domes emerge as patches of Merkel cells and keratinocytes clustered with a previously unsuspected population of Bmp4-expressing dermal cells. Epidermal Noggin overexpression at E14.5 disrupted touch-dome formation but not hair-follicle specification, demonstrating a temporally distinct requirement for BMP signaling in placode-derived structures. Surprisingly, two neuronal populations preferentially targeted touch domes during development but only one persisted in mature touch domes. Finally, Keratin-17-expressing keratinocytes but not Merkel cells were necessary to establish innervation patterns during development. These findings identify key cell types and signaling pathways required for targeting Merkel-cell afferents to discrete mechanosensory compartments.
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Affiliation(s)
- Blair A Jenkins
- Department of Physiology and Cellular BiophysicsColumbia UniversityNew YorkUnited States
- Department of DermatologyColumbia UniversityNew YorkUnited States
| | - Natalia M Fontecilla
- Department of Physiology and Cellular BiophysicsColumbia UniversityNew YorkUnited States
| | - Catherine P Lu
- Robin Neustein Laboratory of Mammalian Development and Cell BiologyHoward Hughes Medical Institute, The Rockefeller UniversityNew YorkUnited States
| | - Elaine Fuchs
- Robin Neustein Laboratory of Mammalian Development and Cell BiologyHoward Hughes Medical Institute, The Rockefeller UniversityNew YorkUnited States
| | - Ellen A Lumpkin
- Department of Physiology and Cellular BiophysicsColumbia UniversityNew YorkUnited States
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7
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Hoffman BU, Baba Y, Griffith TN, Mosharov EV, Woo SH, Roybal DD, Karsenty G, Patapoutian A, Sulzer D, Lumpkin EA. Merkel Cells Activate Sensory Neural Pathways through Adrenergic Synapses. Neuron 2018; 100:1401-1413.e6. [PMID: 30415995 DOI: 10.1016/j.neuron.2018.10.034] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/21/2018] [Accepted: 10/22/2018] [Indexed: 01/06/2023]
Abstract
Epithelial-neuronal signaling is essential for sensory encoding in touch, itch, and nociception; however, little is known about the release mechanisms and neurotransmitter receptors through which skin cells govern neuronal excitability. Merkel cells are mechanosensory epidermal cells that have long been proposed to activate neuronal afferents through chemical synaptic transmission. We employed a set of classical criteria for chemical neurotransmission as a framework to test this hypothesis. RNA sequencing of adult mouse Merkel cells demonstrated that they express presynaptic molecules and biosynthetic machinery for adrenergic transmission. Moreover, live-cell imaging directly demonstrated that Merkel cells mediate activity- and VMAT-dependent release of fluorescent catecholamine neurotransmitter analogs. Touch-evoked firing in Merkel-cell afferents was inhibited either by pre-synaptic silencing of SNARE-mediated vesicle release from Merkel cells or by neuronal deletion of β2-adrenergic receptors. Together, these results identify both pre- and postsynaptic mechanisms through which Merkel cells excite mechanosensory afferents to encode gentle touch. VIDEO ABSTRACT.
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Affiliation(s)
- Benjamin U Hoffman
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA; Program in Neurobiology & Behavior, Columbia University, New York, NY, USA
| | - Yoshichika Baba
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA
| | - Theanne N Griffith
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA
| | - Eugene V Mosharov
- Departments of Psychiatry, Neurology, and Pharmacology, Columbia University: Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Seung-Hyun Woo
- The Scripps Research Institute & Howard Hughes Medical Institute, La Jolla, CA, USA
| | - Daniel D Roybal
- Pharmacology Graduate Program, Columbia University, New York, NY, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University, New York, NY, USA
| | - Ardem Patapoutian
- The Scripps Research Institute & Howard Hughes Medical Institute, La Jolla, CA, USA
| | - David Sulzer
- Departments of Psychiatry, Neurology, and Pharmacology, Columbia University: Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Ellen A Lumpkin
- Department of Physiology & Cellular Biophysics, Columbia University, New York, NY, USA; Program in Neurobiology & Behavior, Columbia University, New York, NY, USA; Department of Dermatology, Columbia University, New York, NY, USA.
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8
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Abstract
The sensation of touch is mediated by mechanosensory neurons that are embedded in skin and relay signals from the periphery to the central nervous system. During embryogenesis, axons elongate from these neurons to make contact with the developing skin. Concurrently, the epithelium of skin transforms from a homogeneous tissue into a heterogeneous organ that is made up of distinct layers and microdomains. Throughout this process, each neuronal terminal must form connections with an appropriate skin region to serve its function. This Review presents current knowledge of the development of the sensory microdomains in mammalian skin and the mechanosensory neurons that innervate them.
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Affiliation(s)
- Blair A Jenkins
- Department of Physiology & Cellular Biophysics and Department of Dermatology, Columbia University in the City of New York, New York, NY 10032, USA
| | - Ellen A Lumpkin
- Department of Physiology & Cellular Biophysics and Department of Dermatology, Columbia University in the City of New York, New York, NY 10032, USA
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9
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Cui L, Miao X, Liang L, Abdus-Saboor I, Olson W, Fleming MS, Ma M, Tao YX, Luo W. Identification of Early RET+ Deep Dorsal Spinal Cord Interneurons in Gating Pain. Neuron 2016; 91:1137-1153. [PMID: 27545714 PMCID: PMC5017914 DOI: 10.1016/j.neuron.2016.07.038] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 04/30/2016] [Accepted: 07/21/2016] [Indexed: 11/29/2022]
Abstract
The gate control theory (GCT) of pain proposes that pain- and touch-sensing neurons antagonize each other through spinal cord dorsal horn (DH) gating neurons. However, the exact neural circuits underlying the GCT remain largely elusive. Here, we identified a new population of deep layer DH (dDH) inhibitory interneurons that express the receptor tyrosine kinase Ret neonatally. These early RET+ dDH neurons receive excitatory as well as polysynaptic inhibitory inputs from touch- and/or pain-sensing afferents. In addition, they negatively regulate DH pain and touch pathways through both pre- and postsynaptic inhibition. Finally, specific ablation of early RET+ dDH neurons increases basal and chronic pain, whereas their acute activation reduces basal pain perception and relieves inflammatory and neuropathic pain. Taken together, our findings uncover a novel spinal circuit that mediates crosstalk between touch and pain pathways and suggest that some early RET+ dDH neurons could function as pain "gating" neurons.
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Affiliation(s)
- Lian Cui
- Department of Neuroscience, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xuerong Miao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Ishmail Abdus-Saboor
- Department of Neuroscience, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - William Olson
- Department of Neuroscience, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael S Fleming
- Department of Neuroscience, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Minghong Ma
- Department of Neuroscience, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA.
| | - Wenqin Luo
- Department of Neuroscience, Perelman School of Medicine, the University of Pennsylvania, Philadelphia, PA 19104, USA.
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Olson W, Dong P, Fleming M, Luo W. The specification and wiring of mammalian cutaneous low-threshold mechanoreceptors. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:389-404. [PMID: 26992078 DOI: 10.1002/wdev.229] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 01/04/2016] [Accepted: 01/12/2016] [Indexed: 11/08/2022]
Abstract
The mammalian cutaneous low-threshold mechanoreceptors (LTMRs) are a diverse set of primary somatosensory neurons that function to sense external mechanical force. Generally, LTMRs are composed of Aβ-LTMRs, Aδ-LTMRs, and C-LTMRs, which have distinct molecular, physiological, anatomical, and functional features. The specification and wiring of each type of mammalian cutaneous LTMRs is established during development by the interplay of transcription factors with trophic factor signalling. In this review, we summarize the cohort of extrinsic and intrinsic factors generating the complex mammalian cutaneous LTMR circuits that mediate our tactile sensations and behaviors. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- William Olson
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter Dong
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael Fleming
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Wenqin Luo
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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11
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Taylor-Clark TE, Wu KY, Thompson JA, Yang K, Bahia PK, Ajmo JM. Thy1.2 YFP-16 transgenic mouse labels a subset of large-diameter sensory neurons that lack TRPV1 expression. PLoS One 2015; 10:e0119538. [PMID: 25746468 PMCID: PMC4351979 DOI: 10.1371/journal.pone.0119538] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/21/2015] [Indexed: 11/18/2022] Open
Abstract
The Thy1.2 YFP-16 mouse expresses yellow fluorescent protein (YFP) in specific subsets of peripheral and central neurons. The original characterization of this model suggested that YFP was expressed in all sensory neurons, and this model has been subsequently used to study sensory nerve structure and function. Here, we have characterized the expression of YFP in the sensory ganglia (DRG, trigeminal and vagal) of the Thy1.2 YFP-16 mouse, using biochemical, functional and anatomical analyses. Despite previous reports, we found that YFP was only expressed in approximately half of DRG and trigeminal neurons and less than 10% of vagal neurons. YFP-expression was only found in medium and large-diameter neurons that expressed neurofilament but not TRPV1. YFP-expressing neurons failed to respond to selective agonists for TRPV1, P2X(2/3 and TRPM8 channels in Ca2+ imaging assays. Confocal analysis of glabrous skin, hairy skin of the back and ear and skeletal muscle indicated that YFP was expressed in some peripheral terminals with structures consistent with their presumed non-nociceptive nature. In summary, the Thy1.2 YFP-16 mouse expresses robust YFP expression in only a subset of sensory neurons. But this mouse model is not suitable for the study of nociceptive nerves or the function of such nerves in pain and neuropathies.
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Affiliation(s)
- Thomas E. Taylor-Clark
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
| | - Kevin Y. Wu
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Julie-Ann Thompson
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Kiseok Yang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Parmvir K. Bahia
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Joanne M. Ajmo
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
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12
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Woo SH, Lumpkin EA, Patapoutian A. Merkel cells and neurons keep in touch. Trends Cell Biol 2014; 25:74-81. [PMID: 25480024 DOI: 10.1016/j.tcb.2014.10.003] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/20/2014] [Accepted: 10/24/2014] [Indexed: 11/18/2022]
Abstract
The Merkel cell-neurite complex is a unique vertebrate touch receptor comprising two distinct cell types in the skin. Its presence in touch-sensitive skin areas was recognized more than a century ago, but the functions of each cell type in sensory transduction have been unclear. Three recent studies demonstrate that Merkel cells are mechanosensitive cells that function in touch transduction via Piezo2. One study concludes that Merkel cells, rather than sensory neurons, are principal sites of mechanotransduction, whereas two other studies report that both Merkel cells and neurons encode mechanical inputs. Together, these studies settle a long-standing debate on whether or not Merkel cells are mechanosensory cells, and enable future investigations of how these skin cells communicate with neurons.
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Affiliation(s)
- Seung-Hyun Woo
- Howard Hughes Medical Institute, Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ellen A Lumpkin
- Departments of Dermatology & Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA.
| | - Ardem Patapoutian
- Howard Hughes Medical Institute, Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037, USA.
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13
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