1
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Wood MB, Nowak N, Fuchs PA. Damage-evoked signals in cochlear neurons and supporting cells. Front Neurol 2024; 15:1361747. [PMID: 38419694 PMCID: PMC10899329 DOI: 10.3389/fneur.2024.1361747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 01/31/2024] [Indexed: 03/02/2024] Open
Abstract
In addition to hearing loss, damage to the cochlea can lead to gain of function pathologies such as hyperacusis. It has been proposed that painful hyperacusis, noxacusis, may be carried to the central nervous system by type II cochlear afferents, sparse, unmyelinated neurons that share morphological and neurochemical traits with nociceptive C-fibers of the somatic nervous system. Also like in skin, damage elicits spreading calcium waves within cochlear epithelia. These are mediated by extracellular ATP combined with IP3-driven release from intracellular calcium stores. Type II afferents are excited by ATP released from damaged epithelia. Thus, the genesis and propagation of epithelial calcium waves is central to cochlear pathology, and presumably hyperacusis. Damage-evoked signals in type II afferents and epithelial cells have been recorded in cochlear explants or semi-intact otic capsules. These efforts have included intracellular electrical recording, use of fluorescent calcium indicators, and visualization of an activity-dependent, intrinsic fluorescent signal. Of relevance to hyperacusis, prior noise-induced hearing loss leads to the generation of prolonged and repetitive activity in type II neurons and surrounding epithelia.
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Affiliation(s)
- Megan Beers Wood
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Baltimore, MD, United States
| | - Nate Nowak
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Baltimore, MD, United States
- The Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Paul Albert Fuchs
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Baltimore, MD, United States
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2
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Gross J, Knipper M, Mazurek B. Candidate Key Proteins in Tinnitus: A Bioinformatic Study of Synaptic Transmission in Spiral Ganglion Neurons. Cell Mol Neurobiol 2023; 43:4189-4207. [PMID: 37736859 PMCID: PMC10661836 DOI: 10.1007/s10571-023-01405-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 08/24/2023] [Indexed: 09/23/2023]
Abstract
To study key proteins associated with changes in synaptic transmission in the spiral ganglion in tinnitus, we build three gene lists from the GeneCard database: 1. Perception of sound (PoS), 2. Acoustic stimulation (AcouStim), and 3. Tinnitus (Tin). Enrichment analysis by the DAVID database resulted in similar Gene Ontology (GO) terms for cellular components in all gene lists, reflecting synaptic structures known to be involved in auditory processing. The STRING protein-protein interaction (PPI) network and the Cytoscape data analyzer were used to identify the top two high-degree proteins (HDPs) and their high-score interaction proteins (HSIPs) identified by the combined score (CS) of the corresponding edges. The top two protein pairs (key proteins) for the PoS are BDNF-GDNF and OTOF-CACNA1D and for the AcouStim process BDNF-NTRK2 and TH-CALB1. The Tin process showed BDNF and NGF as HDPs, with high-score interactions with NTRK1 and NGFR at a comparable level. Compared to the PoS and AcouStim process, the number of HSIPs of key proteins (CS > 90. percentile) increases strongly in Tin. In the PoS and AcouStim networks, BDNF receptor signaling is the dominant pathway, and in the Tin network, the NGF-signaling pathway is of similar importance. Key proteins and their HSIPs are good indicators of biological processes and of signaling pathways characteristic for the normal hearing on the one hand and tinnitus on the other.
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Affiliation(s)
- Johann Gross
- Tinnitus Center, Charité-Universitätsmedizin Berlin, Berlin, Germany.
- Leibniz Society of Science Berlin, Berlin, Germany.
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
- Leibniz Society of Science Berlin, Berlin, Germany
| | - Birgit Mazurek
- Tinnitus Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
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3
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Yang Y, Murtha K, Climer LK, Ceriani F, Thompson P, Hornak AJ, Marcotti W, Simmons DD. Oncomodulin regulates spontaneous calcium signalling and maturation of afferent innervation in cochlear outer hair cells. J Physiol 2023; 601:4291-4308. [PMID: 37642186 PMCID: PMC10621907 DOI: 10.1113/jp284690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023] Open
Abstract
Cochlear outer hair cells (OHCs) are responsible for the exquisite frequency selectivity and sensitivity of mammalian hearing. During development, the maturation of OHC afferent connectivity is refined by coordinated spontaneous Ca2+ activity in both sensory and non-sensory cells. Calcium signalling in neonatal OHCs can be modulated by oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein. Here, we investigated whether OCM regulates OHC spontaneous Ca2+ activity and afferent connectivity during development. Using a genetically encoded Ca2+ sensor (GCaMP6s) expressed in OHCs in wild-type (Ocm+/+ ) and Ocm knockout (Ocm-/- ) littermates, we found increased spontaneous Ca2+ activity and upregulation of purinergic receptors in OHCs from Ocm-/- cochlea immediately following birth. The afferent synaptic maturation of OHCs was delayed in the absence of OCM, leading to an increased number of ribbon synapses and afferent fibres on Ocm-/- OHCs before hearing onset. We propose that OCM regulates the spontaneous Ca2+ signalling in the developing cochlea and the maturation of OHC afferent innervation. KEY POINTS: Cochlear outer hair cells (OHCs) exhibit spontaneous Ca2+ activity during a narrow period of neonatal development. OHC afferent maturation and connectivity requires spontaneous Ca2+ activity. Oncomodulin (OCM, β-parvalbumin), an EF-hand calcium-binding protein, modulates Ca2+ signals in immature OHCs. Using transgenic mice that endogenously expressed a Ca2+ sensor, GCaMP6s, we found increased spontaneous Ca2+ activity and upregulated purinergic receptors in Ocm-/- OHCs. The maturation of afferent synapses in Ocm-/- OHCs was also delayed, leading to an upregulation of ribbon synapses and afferent fibres in Ocm-/- OHCs before hearing onset. We propose that OCM plays an important role in modulating Ca2+ activity, expression of Ca2+ channels and afferent innervation in developing OHCs.
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Affiliation(s)
- Yang Yang
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Kaitlin Murtha
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Leslie K. Climer
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Federico Ceriani
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
| | - Pierce Thompson
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Aubrey J. Hornak
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
| | - Walter Marcotti
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
- Sheffield Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Dwayne D. Simmons
- Department of Biology, Baylor University, 101 Bagby Ave, Waco, TX
- School of Biosciences, University of Sheffield, S10 2TN Sheffield, United Kingdom
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA
- Department of Psychology and Neuroscience, Baylor University, Waco, TX
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4
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Tereshenko V, Maierhofer U, Dotzauer DC, Laengle G, Politikou O, Carrero Rojas G, Festin C, Luft M, Jaklin FJ, Hruby LA, Gohritz A, Farina D, Blumer R, Bergmeister KD, Aszmann OC. Axonal mapping of the motor cranial nerves. Front Neuroanat 2023; 17:1198042. [PMID: 37332322 PMCID: PMC10272770 DOI: 10.3389/fnana.2023.1198042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/12/2023] [Indexed: 06/20/2023] Open
Abstract
Basic behaviors, such as swallowing, speech, and emotional expressions are the result of a highly coordinated interplay between multiple muscles of the head. Control mechanisms of such highly tuned movements remain poorly understood. Here, we investigated the neural components responsible for motor control of the facial, masticatory, and tongue muscles in humans using specific molecular markers (ChAT, MBP, NF, TH). Our findings showed that a higher number of motor axonal population is responsible for facial expressions and tongue movements, compared to muscles in the upper extremity. Sensory axons appear to be responsible for neural feedback from cutaneous mechanoreceptors to control the movement of facial muscles and the tongue. The newly discovered sympathetic axonal population in the facial nerve is hypothesized to be responsible for involuntary control of the muscle tone. These findings shed light on the pivotal role of high efferent input and rich somatosensory feedback in neuromuscular control of finely adjusted cranial systems.
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Affiliation(s)
- Vlad Tereshenko
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
- Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Udo Maierhofer
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Dominik C. Dotzauer
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Gregor Laengle
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Olga Politikou
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Genova Carrero Rojas
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Christopher Festin
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
- Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Matthias Luft
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
- Department of Plastic, Aesthetic and Reconstructive Surgery, University Hospital St. Pölten, Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria
| | - Florian J. Jaklin
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
| | - Laura A. Hruby
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
- Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria
| | - Andreas Gohritz
- Department of Plastic Surgery, University of Basel, Basel, Switzerland
| | - Dario Farina
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Roland Blumer
- Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Konstantin D. Bergmeister
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
- Department of Plastic, Aesthetic and Reconstructive Surgery, University Hospital St. Pölten, Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria
| | - Oskar C. Aszmann
- Clinical Laboratory for Bionic Extremity Reconstruction, Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Vienna, Vienna, Austria
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5
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Sanders TR, Kelley MW. Specification of neuronal subtypes in the spiral ganglion begins prior to birth in the mouse. Proc Natl Acad Sci U S A 2022; 119:e2203935119. [PMID: 36409884 PMCID: PMC9860252 DOI: 10.1073/pnas.2203935119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 10/17/2022] [Indexed: 11/22/2022] Open
Abstract
The afferent innervation of the cochlea is comprised of spiral ganglion neurons (SGNs), which are characterized into four subtypes (Type 1A, B, and C and Type 2). However, little is known about the factors and/or processes that determine each subtype. Here, we present a transcriptional analysis of approximately 5,500 single murine SGNs collected across four developmental time points. All four subtypes are transcriptionally identifiable prior to the onset of coordinated spontaneous activity, indicating that the initial specification process is under genetic control. Trajectory analysis indicates that SGNs initially split into two precursor types (Type 1A/2 and Type 1B/C), followed by subsequent splits to give rise to four transcriptionally distinct subtypes. Differential gene expression, pseudotime, and regulon analyses were used to identify candidate transcription factors which may regulate the subtypes specification process. These results provide insights into SGN development and comprise a transcriptional atlas of SGN maturation across the prenatal period.
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Affiliation(s)
- Tessa R. Sanders
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD20892
| | - Matthew W. Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD20892
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6
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Prior Acoustic Trauma Alters Type II Afferent Activity in the Mouse Cochlea. eNeuro 2021; 8:ENEURO.0383-21.2021. [PMID: 34607806 PMCID: PMC8589282 DOI: 10.1523/eneuro.0383-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 01/11/2023] Open
Abstract
Auditory stimuli travel from the cochlea to the brainstem through type I and type II cochlear afferents. While type I afferents convey information about the frequency, intensity, and timing of sounds, the role of type II afferents remains unresolved. Limited recordings of type II afferents from cochlear apex of prehearing rats reveal they are activated by widespread outer hair cell stimulation, ATP, and by the rupture of nearby outer hair cells. Altogether, these lines of evidence suggest that type II afferents sense loud, potentially damaging levels of sound. To explore this hypothesis further, calcium imaging was used to determine the impact of acoustic trauma on the activity of type II cochlear afferents of young adult mice of both sexes. Two known marker genes (Th, Drd2) and one new marker gene (Tac1), expressed in type II afferents and some other cochlear cell types, drove GCaMP6f expression to reveal calcium transients in response to focal damage in the organ of Corti in all turns of the cochlea. Mature type II afferents responded to acute photoablation damage less often but at greater length compared with prehearing neurons. In addition, days after acoustic trauma, acute photoablation triggered a novel response pattern in type II afferents and surrounding epithelial cells, delayed bursts of activity occurring minutes after the initial response subsided. Overall, calcium imaging can report type II afferent responses to damage even in mature and noise-exposed animals and reveals previously unknown tissue hyperactivity subsequent to acoustic trauma.
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7
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Elliott KL, Kersigo J, Lee JH, Jahan I, Pavlinkova G, Fritzsch B, Yamoah EN. Developmental Changes in Peripherin-eGFP Expression in Spiral Ganglion Neurons. Front Cell Neurosci 2021; 15:678113. [PMID: 34211371 PMCID: PMC8239239 DOI: 10.3389/fncel.2021.678113] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
The two types of spiral ganglion neurons (SGNs), types I and II, innervate inner hair cells and outer hair cells, respectively, within the mammalian cochlea and send another process back to cochlear nuclei in the hindbrain. Studying these two neuronal types has been made easier with the identification of unique molecular markers. One of these markers, peripherin, was shown using antibodies to be present in all SGNs initially but becomes specific to type II SGNs during maturation. We used mice with fluorescently labeled peripherin (Prph-eGFP) to examine peripherin expression in SGNs during development and in aged mice. Using these mice, we confirm the initial expression of Prph-eGFP in both types I and II neurons and eventual restriction to only type II perikarya shortly after birth. However, while Prph-eGFP is uniquely expressed within type II cell bodies by P8, both types I and II peripheral and central processes continue to express Prph-eGFP for some time before becoming downregulated. Only at P30 was there selective type II Prph-eGFP expression in central but not peripheral processes. By 9 months, only the type II cell bodies and more distal central processes retain Prph-eGFP expression. Our results show that Prph-eGFP is a reliable marker for type II SGN cell bodies beyond P8; however, it is not generally a suitable marker for type II processes, except for central processes beyond P30. How the changes in Prph-eGFP expression relate to subsequent protein expression remains to be explored.
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Affiliation(s)
- Karen L Elliott
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | - Jennifer Kersigo
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | - Jeong Han Lee
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV, United States
| | - Israt Jahan
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | | | - Bernd Fritzsch
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | - Ebenezer N Yamoah
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV, United States
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8
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Kitcher SR, Pederson AM, Weisz CJC. Diverse identities and sites of action of cochlear neurotransmitters. Hear Res 2021; 419:108278. [PMID: 34108087 DOI: 10.1016/j.heares.2021.108278] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/30/2021] [Accepted: 05/18/2021] [Indexed: 11/18/2022]
Abstract
Accurate encoding of acoustic stimuli requires temporally precise responses to sound integrated with cellular mechanisms that encode the complexity of stimuli over varying timescales and orders of magnitude of intensity. Sound in mammals is initially encoded in the cochlea, the peripheral hearing organ, which contains functionally specialized cells (including hair cells, afferent and efferent neurons, and a multitude of supporting cells) to allow faithful acoustic perception. To accomplish the demanding physiological requirements of hearing, the cochlea has developed synaptic arrangements that operate over different timescales, with varied strengths, and with the ability to adjust function in dynamic hearing conditions. Multiple neurotransmitters interact to support the precision and complexity of hearing. Here, we review the location of release, action, and function of neurotransmitters in the mammalian cochlea with an emphasis on recent work describing the complexity of signaling.
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Affiliation(s)
- Siân R Kitcher
- Section on Neuronal Circuitry, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, United States
| | - Alia M Pederson
- Section on Neuronal Circuitry, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, United States
| | - Catherine J C Weisz
- Section on Neuronal Circuitry, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, United States.
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9
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Webber JL, Clancy JC, Zhou Y, Yraola N, Homma K, García-Añoveros J. Axodendritic versus axosomatic cochlear efferent termination is determined by afferent type in a hierarchical logic of circuit formation. SCIENCE ADVANCES 2021; 7:7/4/eabd8637. [PMID: 33523928 PMCID: PMC7817091 DOI: 10.1126/sciadv.abd8637] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/03/2020] [Indexed: 05/09/2023]
Abstract
Hearing involves a stereotyped neural network communicating cochlea and brain. How this sensorineural circuit assembles is largely unknown. The cochlea houses two types of mechanosensory hair cells differing in function (sound transmission versus amplification) and location (inner versus outer compartments). Inner (IHCs) and outer hair cells (OHCs) are each innervated by a distinct pair of afferent and efferent neurons: IHCs are contacted by type I afferents receiving axodendritic efferent contacts; OHCs are contacted by type II afferents and axosomatically terminating efferents. Using an Insm1 mouse mutant with IHCs in the position of OHCs, we discover a hierarchical sequence of instructions in which first IHCs attract, and OHCs repel, type I afferents; second, type II afferents innervate hair cells not contacted by type I afferents; and last, afferent fiber type determines if and how efferents innervate, whether axodendritically on the afferent, axosomatically on the hair cell, or not at all.
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Affiliation(s)
- Jemma L Webber
- Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - John C Clancy
- Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Yingjie Zhou
- Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Natalia Yraola
- Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Kazuaki Homma
- Department of Otolaryngology-Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and its Disorders, Northwestern University, Chicago, IL 60611, USA
| | - Jaime García-Añoveros
- Department of Anesthesiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and its Disorders, Northwestern University, Chicago, IL 60611, USA
- Departments of Neurology and Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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10
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Shenton FC, Campbell T, Jones JFX, Pyner S. Distribution and morphology of sensory and autonomic fibres in the subendocardial plexus of the rat heart. J Anat 2021; 238:36-52. [PMID: 32783212 PMCID: PMC7754995 DOI: 10.1111/joa.13284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 01/11/2023] Open
Abstract
Cardiac reflexes originating from sensory receptors in the heart ensure blood supply to vital tissues and organs in the face of constantly changing demands. Atrial volume receptors are mechanically sensitive vagal afferents which relay to the medulla and hypothalamus, affecting vasopressin release and renal sympathetic activity. To date, two anatomically distinct sensory endings have been identified which may subserve cardiac mechanosensation: end-nets and flower-spray endings. To map the distribution of atrial receptors in the subendocardial space, we have double-labelled rat right atrial whole mounts for neurofilament heavy chain (NFH) and synaptic vesicle protein 2 (SV2) and generated high-resolution maps of the rat subendocardial neural plexus at the cavo-atrial region. In order to elucidate the nature of these fibres, double labelling with synaptophysin (SYN) and either NFH, calcitonin gene-related peptide (CGRP), choline acetyltransferase (ChAT) or tyrosine hydroxylase (TH) was performed. The findings show that subendocardial nerve nets are denser at the superior cavo-atrial junction than the mid-atrial region. Adluminal plexuses had the finest diameters and stained positively for synaptic vesicles (SV2 and SYN), CGRP and TH. These plexuses may represent sympathetic post-ganglionic fibres and/or sensory afferents. The latter are candidate substrates for type B volume receptors which are excited by stretch during atrial filling. Deeper nerve fibres appeared coarser and may be cholinergic (positive staining for ChAT). Flower-spray endings were never observed using immunohistochemistry but were delineated clearly with the intravital stain methylene blue. We suggest that differing nerve fibre structures form the basis by which atrial deformation and hence atrial filling is reflected to the brain.
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Affiliation(s)
| | - Thomas Campbell
- Discipline of AnatomySchool of MedicineUniversity College DublinDublin 4Ireland
| | - James F. X. Jones
- Discipline of AnatomySchool of MedicineUniversity College DublinDublin 4Ireland
| | - Susan Pyner
- Department of BiosciencesDurham UniversityDurhamUK
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11
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Wood MB, Nowak N, Mull K, Goldring A, Lehar M, Fuchs PA. Acoustic Trauma Increases Ribbon Number and Size in Outer Hair Cells of the Mouse Cochlea. J Assoc Res Otolaryngol 2020; 22:19-31. [PMID: 33151428 PMCID: PMC7822997 DOI: 10.1007/s10162-020-00777-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/19/2020] [Indexed: 01/01/2023] Open
Abstract
Outer hair cells (OHCs) in the mouse cochlea are contacted by up to three type II afferent boutons. On average, only half of these are postsynaptic to presynaptic ribbons. Mice of both sexes were subjected to acoustic trauma that produced a threshold shift of 44.2 ± 9.1 dB 7 days after exposure. Ribbon synapses of OHCs were quantified in post-trauma and littermate controls using immunolabeling of CtBP2. Visualization with virtual reality was used to determine 3-D cytoplasmic localization of CtBP2 puncta to the synaptic pole of OHCs. Acoustic trauma was associated with a statistically significant increase in the number of synaptic ribbons per OHC. Serial section TEM was carried out on similarly treated mice. This also showed a significant increase in the number of ribbons in post-trauma OHCs, as well as a significant increase in ribbon volume compared to ribbons in control OHCs. An increase in OHC ribbon synapses after acoustic trauma is a novel observation that has implications for OHC:type II afferent signaling. A mathematical model showed that the observed increase in OHC ribbons considered alone could produce a significant increase in action potentials among type II afferent neurons during strong acoustic stimulation.
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Affiliation(s)
- Megan B Wood
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA.
| | - Nathaniel Nowak
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
| | - Keira Mull
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
| | - Adam Goldring
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA.,Sutter Instrument, Co. 1 Digital Drive, Novato, CA, 94949, USA
| | - Mohamed Lehar
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
| | - Paul Albert Fuchs
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
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12
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Kim WB, Kang KW, Sharma K, Yi E. Distribution of K v3 Subunits in Cochlear Afferent and Efferent Nerve Fibers Implies Distinct Role in Auditory Processing. Exp Neurobiol 2020; 29:344-355. [PMID: 33154197 PMCID: PMC7649084 DOI: 10.5607/en20043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 11/19/2022] Open
Abstract
Kv3 family K+ channels, by ensuring speedy repolarization of action potential, enable rapid and high frequency neuronal firing and high precision temporal coding of auditory information in various auditory synapses in the brain. Expression of different Kv3 subtypes within the auditory end organ has been reported. Yet, their precise role at the hair cell synaptic transmission has not been fully elucidated. Using immunolabeling and confocal microscopy we examined the expression pattern of different Kv3 family K+ channel subunits in the nerve fibers innervating the cochlear hair cells. Kv3.1b was found in NKA-positive type 1 afferent fibers, exhibiting high signal intensity at the cell body, the unmyelinated dendritic segment, first heminode and nodes of Ranvier. Kv3.3 signal was detected in the cell body and the unmyelinated dendritic segment of NKA-positive type 1 afferent fibers but not in peripherin-positive type 2 afferent. Kv3.4 was found in ChAT-positive LOC and MOC efferent fibers as well as peripherin-positive type 2 afferent fibers. Such segregated expression pattern implies that each Kv3 subunits participate in different auditory tasks, for example, Kv3.1b and Kv3.3 in ascending signaling while Kv3.4 in feedback upon loud noise exposure.
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Affiliation(s)
- Woo Bin Kim
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Kwon-Woo Kang
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Kushal Sharma
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Eunyoung Yi
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
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13
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Wu JS, Yi E, Manca M, Javaid H, Lauer AM, Glowatzki E. Sound exposure dynamically induces dopamine synthesis in cholinergic LOC efferents for feedback to auditory nerve fibers. eLife 2020; 9:52419. [PMID: 31975688 PMCID: PMC7043886 DOI: 10.7554/elife.52419] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/23/2020] [Indexed: 11/13/2022] Open
Abstract
Lateral olivocochlear (LOC) efferent neurons modulate auditory nerve fiber (ANF) activity using a large repertoire of neurotransmitters, including dopamine (DA) and acetylcholine (ACh). Little is known about how individual neurotransmitter systems are differentially utilized in response to the ever-changing acoustic environment. Here we present quantitative evidence in rodents that the dopaminergic LOC input to ANFs is dynamically regulated according to the animal's recent acoustic experience. Sound exposure upregulates tyrosine hydroxylase, an enzyme responsible for dopamine synthesis, in cholinergic LOC intrinsic neurons, suggesting that individual LOC neurons might at times co-release ACh and DA. We further demonstrate that dopamine down-regulates ANF firing rates by reducing both the hair cell release rate and the size of synaptic events. Collectively, our results suggest that LOC intrinsic neurons can undergo on-demand neurotransmitter re-specification to re-calibrate ANF activity, adjust the gain at hair cell/ANF synapses, and possibly to protect these synapses from noise damage.
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Affiliation(s)
- Jingjing Sherry Wu
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Hearing and Balance, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Eunyoung Yi
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan-gun, Republic of Korea
| | - Marco Manca
- The Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Hearing and Balance, The Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Hamad Javaid
- The Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Hearing and Balance, The Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Amanda M Lauer
- The Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Hearing and Balance, The Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Elisabeth Glowatzki
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, United States.,The Center for Hearing and Balance, The Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, United States
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14
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Johnson SL, Safieddine S, Mustapha M, Marcotti W. Hair Cell Afferent Synapses: Function and Dysfunction. Cold Spring Harb Perspect Med 2019; 9:a033175. [PMID: 30617058 PMCID: PMC6886459 DOI: 10.1101/cshperspect.a033175] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
To provide a meaningful representation of the auditory landscape, mammalian cochlear hair cells are optimized to detect sounds over an incredibly broad range of frequencies and intensities with unparalleled accuracy. This ability is largely conferred by specialized ribbon synapses that continuously transmit acoustic information with high fidelity and sub-millisecond precision to the afferent dendrites of the spiral ganglion neurons. To achieve this extraordinary task, ribbon synapses employ a unique combination of molecules and mechanisms that are tailored to sounds of different frequencies. Here we review the current understanding of how the hair cell's presynaptic machinery and its postsynaptic afferent connections are formed, how they mature, and how their function is adapted for an accurate perception of sound.
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Affiliation(s)
- Stuart L Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Saaid Safieddine
- UMRS 1120, Institut Pasteur, Paris, France
- Sorbonne Universités, UPMC Université Paris 06, Complexité du Vivant, Paris, France
| | - Mirna Mustapha
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
- Department of Otolaryngology-Head & Neck Surgery, Stanford University, Stanford, California 94035
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
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15
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Regulation of Noise-Induced Loss of Serotonin Transporters with Resveratrol in a Rat Model Using 4-[ 18F]-ADAM/Small-Animal Positron Emission Tomography. Molecules 2019; 24:molecules24071344. [PMID: 30959762 PMCID: PMC6480549 DOI: 10.3390/molecules24071344] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/28/2019] [Accepted: 04/04/2019] [Indexed: 11/16/2022] Open
Abstract
Serotonin (5-HT) plays a crucial role in modulating the afferent fiber discharge rate in the inferior colliculus, auditory cortex, and other nuclei of the ascending auditory system. Resveratrol, a natural polyphenol phytoalexin, can inhibit serotonin transporters (SERT) to increase synaptic 5-HT levels. In this study, we investigated the effects of resveratrol on noise-induced damage in the serotonergic system. Male Sprague-Dawley rats were anaesthetized and exposed to an 8-kHz tone at 116 dB for 3.5 h. Resveratrol (30 mg/kg, intraperitoneal injection [IP]) and citalopram (20 mg/kg, IP), a specific SERT inhibitor used as a positive control, were administered once a day for four consecutive days, with the first treatment occurring 2 days before noise exposure. Auditory brainstem response testing and positron emission tomography (PET) with N,N-dimethyl-2-(2-amino-4-[18F]fluorophenylthio)benzylamine (4-[18F]-ADAM, a specific radioligand for SERT) were used to evaluate functionality of the auditory system and integrity of the serotonergic system, respectively, before and after noise exposure. Finally, immunohistochemistry was performed 1 day after the last PET scan. Our results indicate that noise-induced serotonergic fiber loss occurred in multiple brain regions including the midbrain, thalamus, hypothalamus, striatum, auditory cortex, and frontal cortex. This noise-induced damage to the serotonergic system was ameliorated in response to treatment with resveratrol and citalopram. However, noise exposure increased the hearing threshold in the rats regardless of drug treatment status. We conclude that resveratrol has protective effects against noise-induced loss of SERT.
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16
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Vyas P, Wu JS, Jimenez A, Glowatzki E, Fuchs PA. Characterization of transgenic mouse lines for labeling type I and type II afferent neurons in the cochlea. Sci Rep 2019; 9:5549. [PMID: 30944354 PMCID: PMC6447598 DOI: 10.1038/s41598-019-41770-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/14/2019] [Indexed: 11/09/2022] Open
Abstract
The cochlea is innervated by type I and type II afferent neurons. Type I afferents are myelinated, larger diameter neurons that send a single dendrite to contact a single inner hair cell, whereas unmyelinated type II afferents are fewer in number and receive input from many outer hair cells. This strikingly differentiated innervation pattern strongly suggests specialized functions. Those functions could be investigated with specific genetic markers that enable labeling and manipulating each afferent class without significantly affecting the other. Here three mouse models were characterized and tested for specific labeling of either type I or type II cochlear afferents. Nos1CreER mice showed selective labeling of type I afferent fibers, Slc6a4-GFP mice labeled type II fibers with a slight preference for the apical cochlea, and Drd2-Cre mice selectively labeled type II afferent neurons nearer the cochlear base. In conjunction with the Th2A-CreER and CGRPα-EGFP lines described previously for labeling type II fibers, the mouse lines reported here comprise a promising toolkit for genetic manipulations of type I and type II cochlear afferent fibers.
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Affiliation(s)
- Pankhuri Vyas
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Jingjing Sherry Wu
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Adrian Jimenez
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Elisabeth Glowatzki
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Paul Albert Fuchs
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA. .,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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17
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Petitpré C, Wu H, Sharma A, Tokarska A, Fontanet P, Wang Y, Helmbacher F, Yackle K, Silberberg G, Hadjab S, Lallemend F. Neuronal heterogeneity and stereotyped connectivity in the auditory afferent system. Nat Commun 2018; 9:3691. [PMID: 30209249 PMCID: PMC6135759 DOI: 10.1038/s41467-018-06033-3] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 07/31/2018] [Indexed: 01/07/2023] Open
Abstract
Spiral ganglion (SG) neurons of the cochlea convey all auditory inputs to the brain, yet the cellular and molecular complexity necessary to decode the various acoustic features in the SG has remained unresolved. Using single-cell RNA sequencing, we identify four types of SG neurons, including three novel subclasses of type I neurons and the type II neurons, and provide a comprehensive genetic framework that define their potential synaptic communication patterns. The connectivity patterns of the three subclasses of type I neurons with inner hair cells and their electrophysiological profiles suggest that they represent the intensity-coding properties of auditory afferents. Moreover, neuron type specification is already established at birth, indicating a neuronal diversification process independent of neuronal activity. Thus, this work provides a transcriptional catalog of neuron types in the cochlea, which serves as a valuable resource for dissecting cell-type-specific functions of dedicated afferents in auditory perception and in hearing disorders.
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Affiliation(s)
- Charles Petitpré
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Haohao Wu
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Anil Sharma
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Anna Tokarska
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Paula Fontanet
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Yiqiao Wang
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Françoise Helmbacher
- Aix-Marseille Université, CNRS UMR7288, Institut de Biologie du Développement de Marseille (IBDM), 13009, Marseille, France
| | - Kevin Yackle
- Department of Physiology, University of California-San Francisco, San Francisco, CA, 94158, USA
| | - Gilad Silberberg
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - Saida Hadjab
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden
| | - François Lallemend
- Department of Neuroscience, Karolinska Institutet, Biomedicum, Stockholm, 171 77, Sweden.
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18
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Sun S, Babola T, Pregernig G, So KS, Nguyen M, Su SSM, Palermo AT, Bergles DE, Burns JC, Müller U. Hair Cell Mechanotransduction Regulates Spontaneous Activity and Spiral Ganglion Subtype Specification in the Auditory System. Cell 2018; 174:1247-1263.e15. [PMID: 30078710 PMCID: PMC6429032 DOI: 10.1016/j.cell.2018.07.008] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/23/2018] [Accepted: 07/02/2018] [Indexed: 01/06/2023]
Abstract
Type I spiral ganglion neurons (SGNs) transmit sound information from cochlear hair cells to the CNS. Using transcriptome analysis of thousands of single neurons, we demonstrate that murine type I SGNs consist of subclasses that are defined by the expression of subsets of transcription factors, cell adhesion molecules, ion channels, and neurotransmitter receptors. Subtype specification is initiated prior to the onset of hearing during the time period when auditory circuits mature. Gene mutations linked to deafness that disrupt hair cell mechanotransduction or glutamatergic signaling perturb the firing behavior of SGNs prior to hearing onset and disrupt SGN subtype specification. We thus conclude that an intact hair cell mechanotransduction machinery is critical during the pre-hearing period to regulate the firing behavior of SGNs and their segregation into subtypes. Because deafness is frequently caused by defects in hair cells, our findings have significant ramifications for the etiology of hearing loss and its treatment.
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Affiliation(s)
- Shuohao Sun
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Travis Babola
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Gabriela Pregernig
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Kathy S So
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Matthew Nguyen
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Shin-San M Su
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Adam T Palermo
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA
| | - Dwight E Bergles
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Joseph C Burns
- Decibel Therapeutics, 1325 Boylston Street, Suite 500, Boston, MA 02215, USA.
| | - Ulrich Müller
- The Solomon Snyder Department of Neuroscience and Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
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19
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Ibrahim LA, Huang JJ, Wang SZ, Kim YJ, Zhang LI, Tao HW. Sparse Labeling and Neural Tracing in Brain Circuits by STARS Strategy: Revealing Morphological Development of Type II Spiral Ganglion Neurons. Cereb Cortex 2018; 31:5049854. [PMID: 29982390 DOI: 10.1093/cercor/bhy154] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 11/12/2022] Open
Abstract
Elucidating axonal and dendritic projection patterns of individual neurons is a key for understanding the cytoarchitecture of neural circuits in the brain. This requires genetic approaches to achieve Golgi-like sparse labeling of desired types of neurons. Here, we explored a novel strategy of stochastic gene activation with regulated sparseness (STARS), in which the stochastic choice between 2 competing Cre-lox recombination events is controlled by varying the lox efficiency and cassette length. In a created STARS transgenic mouse crossed with various Cre driver lines, sparse neuronal labeling with a relatively uniform level of sparseness was achieved across different brain regions and cell types in both central and peripheral nervous systems. Tracing of individual type II peripheral auditory fibers revealed for the first time that they undergo experience-dependent developmental refinement, which is impaired by attenuating external sound input. Our results suggest that STARS strategy can be applied for circuit mapping and sparse gene manipulation.
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Affiliation(s)
- Leena A Ibrahim
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Junxiang J Huang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Medical Biology Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Sheng-Zhi Wang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Young J Kim
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - L I Zhang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - H W Tao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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20
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Wu JS, Vyas P, Glowatzki E, Fuchs PA. Opposing expression gradients of calcitonin-related polypeptide alpha (Calca/Cgrpα) and tyrosine hydroxylase (Th) in type II afferent neurons of the mouse cochlea. J Comp Neurol 2017; 526:425-438. [PMID: 29055051 DOI: 10.1002/cne.24341] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 10/04/2017] [Accepted: 10/10/2017] [Indexed: 12/20/2022]
Abstract
Type II spiral ganglion neurons (SGNs) are small caliber, unmyelinated afferents that extend dendritic arbors hundreds of microns along the cochlear spiral, contacting many outer hair cells (OHCs). Despite these many contacts, type II afferents are insensitive to sound and only weakly depolarized by glutamate release from OHCs. Recent studies suggest that type II afferents may be cochlear nociceptors, and can be excited by ATP released during tissue damage, by analogy to somatic pain-sensing C-fibers. The present work compares the expression patterns among cochlear type II afferents of two genes found in C-fibers: calcitonin-related polypeptide alpha (Calca/Cgrpα), specific to pain-sensing C-fibers, and tyrosine hydroxylase (Th), specific to low-threshold mechanoreceptive C-fibers, which was shown previously to be a selective biomarker of type II versus type I cochlear afferents (Vyas et al., ). Whole-mount cochlear preparations from 3-week- to 2-month-old CGRPα-EGFP (GENSAT) mice showed expression of Cgrpα in a subset of SGNs with type II-like peripheral dendrites extending beneath OHCs. Double labeling with other molecular markers confirmed that the labeled SGNs were neither type I SGNs nor olivocochlear efferents. Cgrpα starts to express in type II SGNs before hearing onset, but the expression level declines in the adult. The expression patterns of Cgrpα and Th formed opposing gradients, with Th being preferentially expressed in apical and Cgrpα in basal type II afferent neurons, indicating heterogeneity among type II afferent neurons. The expression of Th and Cgrpα was not mutually exclusive and co-expression could be observed, most abundantly in the middle cochlear turn.
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Affiliation(s)
- Jingjing Sherry Wu
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Pankhuri Vyas
- The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Elisabeth Glowatzki
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Paul Albert Fuchs
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,The Center for Hearing and Balance and the Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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21
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Nishimura K, Noda T, Dabdoub A. Dynamic Expression of Sox2, Gata3, and Prox1 during Primary Auditory Neuron Development in the Mammalian Cochlea. PLoS One 2017; 12:e0170568. [PMID: 28118374 PMCID: PMC5261741 DOI: 10.1371/journal.pone.0170568] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/06/2017] [Indexed: 12/15/2022] Open
Abstract
Primary auditory neurons (PANs) connect cochlear sensory hair cells in the mammalian inner ear to cochlear nucleus neurons in the brainstem. PANs develop from neuroblasts delaminated from the proneurosensory domain of the otocyst and keep maturing until the onset of hearing after birth. There are two types of PANs: type I, which innervate the inner hair cells (IHCs), and type II, which innervate the outer hair cells (OHCs). Glial cells surrounding these neurons originate from neural crest cells and migrate to the spiral ganglion. Several transcription factors are known to regulate the development and differentiation of PANs. Here we systematically examined the spatiotemporal expression of five transcription factors: Sox2, Sox10, Gata3, Mafb, and Prox1 from early delamination at embryonic day (E) 10.5 to adult. We found that Sox2 and Sox10 were initially expressed in the proneurosensory cells in the otocyst (E10.5). By E12.75 both Sox2 and Sox10 were downregulated in the developing PANs; however, Sox2 expression transiently increased in the neurons around birth. Furthermore, both Sox2 and Sox10 continued to be expressed in spiral ganglion glial cells. We also show that Gata3 and Prox1 were first expressed in all developing neurons, followed by a decrease in expression of Gata3 and Mafb in type I PANs and Prox1 in type II PANs as they matured. Moreover, we describe two subtypes of type II neurons based on Peripherin expression. These results suggest that Sox2, Gata3 and Prox1 play a role during neurogenesis as well as maturation of the PANs.
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Affiliation(s)
- Koji Nishimura
- Shiga Medical Center Research Institute, Moriyama, Shiga, Japan
| | - Teppei Noda
- Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Alain Dabdoub
- Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
- Department of Otolaryngology – Head & Neck Surgery, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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