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Clancy S, Xie N, Muttikkal TE, Wang J, Fateh E, Smith M, Wilson P, Smith M, Hogan A, Sutherland A, Lu X. Rac1 and Nectin3 are essential for PCP-directed axon guidance in the peripheral auditory system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.05.597585. [PMID: 38895287 PMCID: PMC11185701 DOI: 10.1101/2024.06.05.597585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Our sense of hearing is critically dependent on the spiral ganglion neurons (SGNs) that connect the sound receptors in the organ of Corti (OC) to the cochlear nuclei of the hindbrain. Type I SGNs innervate inner hair cells (IHCs) to transmit sound signals, while type II SGNs (SGNIIs) innervate outer hair cells (OHCs) to detect moderate-to-intense sound. During development, SGNII afferents make a characteristic 90-degree turn toward the base of the cochlea and innervate multiple OHCs. It has been shown that the Planar Cell Polarity (PCP) pathway acts non-autonomously to mediate environmental cues in the cochlear epithelium for SGNII afferent turning towards the base. However, the underlying mechanisms are unknown. Here, we present evidence that PCP signaling regulates multiple downstream effectors to influence cell adhesion and the cytoskeleton in cochlear supporting cells (SCs), which serve as intermediate targets of SGNII afferents. We show that the core PCP gene Vangl2 regulates the localization of the small GTPase Rac1 and the cell adhesion molecule Nectin3 at SC-SC junctions through which SGNII afferents travel. Through in vivo genetic analysis, we also show that loss of Rac1 or Nectin3 partially phenocopied SGNII peripheral afferent turning defects in Vangl2 mutants, and that Rac1 plays a non-autonomous role in this process in part by regulating PCP protein localization at the SC-SC junctions. Additionally, epistasis analysis indicates that Nectin3 and Rac1 likely act in the same genetic pathway to control SGNII afferent turning. Together, these experiments identify Nectin3 and Rac1 as novel regulators of PCP-directed SGNII axon guidance in the cochlea.
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Affiliation(s)
- Shaylyn Clancy
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Nicholas Xie
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | | | - Jasmine Wang
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Esha Fateh
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Margaret Smith
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Phillip Wilson
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Matthew Smith
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Arielle Hogan
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Ann Sutherland
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
| | - Xiaowei Lu
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, 22903, United States
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2
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Shahab M, Rosati R, Stemmer PM, Dombkowski A, Jamesdaniel S. Quantitative profiling of cochlear synaptosomal proteins in cisplatin-induced synaptic dysfunction. Hear Res 2024; 447:109022. [PMID: 38705005 PMCID: PMC11116033 DOI: 10.1016/j.heares.2024.109022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/19/2024] [Accepted: 04/26/2024] [Indexed: 05/07/2024]
Abstract
The disruption of ribbon synapses in the cochlea impairs the transmission of auditory signals from the cochlear sensory receptor cells to the auditory cortex. Although cisplatin-induced loss of ribbon synapses is well-documented, and studies have reported nitration of cochlear proteins after cisplatin treatment, yet the underlying mechanism of cochlear synaptopathy is not fully understood. This study tests the hypothesis that cisplatin treatment alters the abundance of cochlear synaptosomal proteins, and selective targeting of nitrative stress prevents the associated synaptic dysfunction. Auditory brainstem responses of mice treated with cisplatin showed a reduction in amplitude and an increase in latency of wave I, indicating cisplatin-induced synaptic dysfunction. The mass spectrometry analysis of cochlear synaptosomal proteins identified 102 proteins that decreased in abundance and 249 that increased in abundance after cisplatin treatment. Pathway analysis suggested that the dysregulated proteins were involved in calcium binding, calcium ion regulation, synapses, and endocytosis pathways. Inhibition of nitrative stress by co-treatment with MnTBAP, a peroxynitrite scavenger, attenuated cisplatin-induced changes in the abundance of 27 proteins. Furthermore, MnTBAP co-treatment prevented the cisplatin-induced decrease in the amplitude and increase in the latency of wave I. Together, these findings suggest a potential role of oxidative/nitrative stress in cisplatin-induced cochlear synaptic dysfunction.
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Affiliation(s)
- Monazza Shahab
- Department of Pharmacology, Wayne State University, Detroit, MI, USA; Institute of Environment Health Science, Wayne State University, Detroit, MI, USA
| | - Rita Rosati
- Institute of Environment Health Science, Wayne State University, Detroit, MI, USA
| | - Paul M Stemmer
- Institute of Environment Health Science, Wayne State University, Detroit, MI, USA
| | - Alan Dombkowski
- Department of Pediatrics, Wayne State University, Detroit, MI, USA
| | - Samson Jamesdaniel
- Department of Pharmacology, Wayne State University, Detroit, MI, USA; Institute of Environment Health Science, Wayne State University, Detroit, MI, USA.
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3
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Nitta Y, Kurioka T, Mogi S, Sano H, Yamashita T. Suppression of the TGF-β signaling exacerbates degeneration of auditory neurons in kanamycin-induced ototoxicity in mice. Sci Rep 2024; 14:10910. [PMID: 38740884 PMCID: PMC11091189 DOI: 10.1038/s41598-024-61630-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 05/08/2024] [Indexed: 05/16/2024] Open
Abstract
Transforming growth factor-β (TGF-β) signaling plays a significant role in multiple biological processes, including inflammation, immunity, and cell death. However, its specific impact on the cochlea remains unclear. In this study, we aimed to investigate the effects of TGF-β signaling suppression on auditory function and cochlear pathology in mice with kanamycin-induced ototoxicity. Kanamycin and furosemide (KM-FS) were systemically administered to 8-week-old C57/BL6 mice, followed by immediate topical application of a TGF-β receptor inhibitor (TGF-βRI) onto the round window membrane. Results showed significant TGF-β receptor upregulation in spiral ganglion neurons (SGNs) after KM-FA ototoxicity, whereas expression levels in the TGF-βRI treated group remained unchanged. Interestingly, despite no significant change in cochlear TGF-β expression after KM-FS ototoxicity, TGF-βRI treatment resulted in a significant decrease in TGF-β signaling. Regarding auditory function, TGF-βRI treatment offered no therapeutic effects on hearing thresholds and hair cell survival following KM-FS ototoxicity. However, SGN loss and macrophage infiltration were significantly increased with TGF-βRI treatment. These results imply that inhibition of TGF-β signaling after KM-FS ototoxicity promotes cochlear inflammation and SGN degeneration.
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Affiliation(s)
- Yoshihiro Nitta
- Department of Otorhinolaryngology and Head and Neck Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan.
| | - Takaomi Kurioka
- Department of Otorhinolaryngology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan.
| | - Sachiyo Mogi
- Department of Otorhinolaryngology and Head and Neck Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Hajime Sano
- School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Taku Yamashita
- Department of Otorhinolaryngology and Head and Neck Surgery, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
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4
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Slika E, Fuchs PA. Genetic tools for studying cochlear inhibition. Front Cell Neurosci 2024; 18:1372948. [PMID: 38560293 PMCID: PMC10978695 DOI: 10.3389/fncel.2024.1372948] [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: 01/18/2024] [Accepted: 02/28/2024] [Indexed: 04/04/2024] Open
Abstract
Efferent feedback to the mammalian cochlea includes cholinergic medial olivocochlear neurons (MOCs) that release ACh to hyperpolarize and shunt the voltage change that drives electromotility of outer hair cells (OHCs). Via brainstem connectivity, MOCs are activated by sound in a frequency- and intensity-dependent manner, thereby reducing the amplification of cochlear vibration provided by OHC electromotility. Among other roles, this efferent feedback protects the cochlea from acoustic trauma. Lesion studies, as well as a variety of genetic mouse models, support the hypothesis of efferent protection from acoustic trauma. Genetic knockout and gain-of-function knockin of the unique α9α10-containing nicotinic acetylcholine receptor (nAChR) in hair cells show that acoustic protection correlates with the efficacy of cholinergic inhibition of OHCs. This protective effect was replicated by viral transduction of the gain-of-function α9L9'T nAChR into α9-knockout mice. Continued progress with "efferent gene therapy" will require a reliable method for visualizing nAChR expression in cochlear hair cells. To that end, mice expressing HA-tagged α9 or α10 nAChRs were generated using CRISPR technology. This progress will facilitate continued study of the hair cell nAChR as a therapeutic target to prevent hearing loss and potentially to ameliorate associated pathologies such as hyperacusis.
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Affiliation(s)
| | - Paul Albert Fuchs
- The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Johns Hopkins, University School of Medicine Baltimore, Baltimore, MD, United States
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Kim J, Martinez E, Qiu J, Zhouli Ni J, Kwan KY. Chromatin remodeling protein CHD4 regulates axon guidance of spiral ganglion neurons in developing cochlea. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.578202. [PMID: 38352369 PMCID: PMC10862897 DOI: 10.1101/2024.01.31.578202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
The chromodomain helicase binding protein 4 (CHD4) is an ATP-dependent chromatin remodeler. De-novo pathogenic variants of CHD4 cause Sifrim-Hitz-Weiss syndrome (SIHIWES). Patients with SIHIWES show delayed development, intellectual disability, facial dysmorphism, and hearing loss. Many cochlear cell types, including spiral ganglion neurons (SGNs), express CHD4. SGNs are the primary afferent neurons that convey sound information from the cochlea, but the function of CHD4 in SGNs is unknown. We employed the Neurog1(Ngn1) CreERT2 Chd4 conditional knockout animals to delete Chd4 in SGNs. SGNs are classified as type I and type II neurons. SGNs lacking CHD4 showed abnormal fasciculation of type I neurons along with improper pathfinding of type II fibers. CHD4 binding to chromatin from immortalized multipotent otic progenitor-derived neurons was used to identify candidate target genes in SGNs. Gene ontology analysis of CHD4 target genes revealed cellular processes involved in axon guidance, axonal fasciculation, and ephrin receptor signaling pathway. We validated increased Epha4 transcripts in SGNs from Chd4 conditional knockout cochleae. The results suggest that CHD4 attenuates the transcription of axon guidance genes to form the stereotypic pattern of SGN peripheral projections. The results implicate epigenetic changes in circuit wiring by modulating axon guidance molecule expression and provide insights into neurodevelopmental diseases.
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Affiliation(s)
- Jihyun Kim
- Keck Center for Collaborative Neuroscience and Stem Cell Research Center, Rutgers University, Piscataway, NJ 08854, USA
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Edward Martinez
- Keck Center for Collaborative Neuroscience and Stem Cell Research Center, Rutgers University, Piscataway, NJ 08854, USA
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Jingyun Qiu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
| | - Julie Zhouli Ni
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Kelvin Y. Kwan
- Keck Center for Collaborative Neuroscience and Stem Cell Research Center, Rutgers University, Piscataway, NJ 08854, USA
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
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Lee JH, Park S, Perez-Flores MC, Chen Y, Kang M, Choi J, Levine L, Gratton MA, Zhao J, Notterpek L, Yamoah EN. Demyelination and Na + Channel Redistribution Underlie Auditory and Vestibular Dysfunction in PMP22-Null Mice. eNeuro 2024; 11:ENEURO.0462-23.2023. [PMID: 38378628 PMCID: PMC11059428 DOI: 10.1523/eneuro.0462-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 02/22/2024] Open
Abstract
Altered expression of peripheral myelin protein 22 (PMP22) results in demyelinating peripheral neuropathy. PMP22 exhibits a highly restricted tissue distribution with marked expression in the myelinating Schwann cells of peripheral nerves. Auditory and vestibular Schwann cells and the afferent neurons also express PMP22, suggesting a unique role in hearing and balancing. Indeed, neuropathic patients diagnosed with PMP22-linked hereditary neuropathies often present with auditory and balance deficits, an understudied clinical complication. To investigate the mechanism by which abnormal expression of PMP22 may cause auditory and vestibular deficits, we studied gene-targeted PMP22-null mice. PMP22-null mice exhibit an unsteady gait, have difficulty maintaining balance, and live for only ∼3-5 weeks relative to unaffected littermates. Histological analysis of the inner ear revealed reduced auditory and vestibular afferent nerve myelination and profound Na+ channel redistribution without PMP22. Yet, Na+ current density was unaltered, in stark contrast to increased K+ current density. Atypical postsynaptic densities and a range of neuronal abnormalities in the organ of Corti were also identified. Analyses of auditory brainstem responses (ABRs) and vestibular sensory-evoked potential (VsEP) revealed that PMP22-null mice had auditory and vestibular hypofunction. These results demonstrate that PMP22 is required for hearing and balance, and the protein is indispensable for the formation and maintenance of myelin in the peripheral arm of the eighth nerve. Our findings indicate that myelin abnormalities and altered signal propagation in the peripheral arm of the auditory nerve are likely causes of auditory deficits in patients with PMP22-linked neuropathies.
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Affiliation(s)
- Jeong Han Lee
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
| | - Seojin Park
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
- Prestige BioPharma, Busan 67264, South Korea
| | - Maria C Perez-Flores
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
| | - Yingying Chen
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
| | - Mincheol Kang
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
- Prestige BioPharma, Busan 67264, South Korea
| | - Jinsil Choi
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
| | - Lauren Levine
- Program in Audiology and Communication Sciences, Washington University, St. Louis 63110, Missouri
| | | | - Jie Zhao
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
| | - Lucia Notterpek
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno 89557, Nevada
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7
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Dunbar RIM. The origins and function of musical performance. Front Psychol 2023; 14:1257390. [PMID: 38022957 PMCID: PMC10667447 DOI: 10.3389/fpsyg.2023.1257390] [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: 07/12/2023] [Accepted: 09/29/2023] [Indexed: 12/01/2023] Open
Abstract
Music is widely recognised as a human universal, yet there is no agreed explanation for its function, or why and when it evolved. I summarise experimental evidence that the primary function of musicking lies in social bonding, both at the dyadic and community levels, via the effect that performing any form of music has on the brain's endorphin system (the principal neurohormonal basis for social bonding in primates). The many other functions associated with music-making (mate choice, pleasure, coalition signalling, etc) are all better understood as derivative of this, either as secondary selection pressures or as windows of evolutionary opportunity (exaptations). If music's function is primarily as an adjunct of the social bonding mechanism (a feature it shares with laughter, feasting, storytelling and the rituals of religion), then reverse engineering the problem suggests that the capacity for music-making most likely evolved with the appearance of archaic humans. This agrees well with anatomical evidence for the capacity to sing.
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Affiliation(s)
- Robin I. M. Dunbar
- Department of Experimental Psychology, University of Oxford, Radcliffe Quarter, Oxford, United Kingdom
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8
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Nomdedeu-Sancho G, Alsina B. Wiring the senses: Factors that regulate peripheral axon pathfinding in sensory systems. Dev Dyn 2023; 252:81-103. [PMID: 35972036 PMCID: PMC10087148 DOI: 10.1002/dvdy.523] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 01/04/2023] Open
Abstract
Sensory neurons of the head are the ones that transmit the information about the external world to our brain for its processing. Axons from cranial sensory neurons sense different chemoattractant and chemorepulsive molecules during the journey and in the target tissue to establish the precise innervation with brain neurons and/or receptor cells. Here, we aim to unify and summarize the available information regarding molecular mechanisms guiding the different afferent sensory axons of the head. By putting the information together, we find the use of similar guidance cues in different sensory systems but in distinct combinations. In vertebrates, the number of genes in each family of guidance cues has suffered a great expansion in the genome, providing redundancy, and robustness. We also discuss recently published data involving the role of glia and mechanical forces in shaping the axon paths. Finally, we highlight the remaining questions to be addressed in the field.
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Affiliation(s)
- Gemma Nomdedeu-Sancho
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
| | - Berta Alsina
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
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Chen X, Wan H, Bai Y, Zhang Y, Hua Q. Advances in Understanding the Notch Signaling Pathway in the Cochlea. Curr Pharm Des 2023; 29:3266-3273. [PMID: 37990430 DOI: 10.2174/0113816128273532231103110910] [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: 08/18/2023] [Accepted: 10/17/2023] [Indexed: 11/23/2023]
Abstract
The cochlear structure is highly complex and specific, and its development is regulated by multiple signaling pathways. Abnormalities in cochlear development can lead to different degrees of loss of function. Hair cells (HCs), which are difficult to regenerate in the mature mammalian cochlea, are susceptible to damage from noise and ototoxic drugs, and damage to HCs can cause hearing loss to varying degrees. Notch, a classical developmental signaling molecule, has been shown to be closely associated with embryonic cochlear development and plays an important role in HC regeneration in mammals, suggesting that the Notch signaling pathway may be a potential therapeutic target for cochlear development and hearing impairment due to HC damage. In recent years, the important role of the Notch signaling pathway in the cochlea has received increasing attention. In this paper, we review the role of Notch signaling in cochlear development and HC regeneration, with the aim of providing new research ideas for the prevention and treatment of related diseases.
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Affiliation(s)
- Xiaoying Chen
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Huanzhi Wan
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Yutong Bai
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Yuanyuan Zhang
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, China
| | - Qingquan Hua
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan 430060, China
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Trevino M, Escabi C, Swanner H, Pawlowski K, Lobarinas E. No Reduction in the 226-Hz Probe Tone Acoustic Reflex Amplitude Following Severe Inner Hair Cell Loss in Chinchillas. J Assoc Res Otolaryngol 2022; 23:593-602. [PMID: 35902434 PMCID: PMC9613837 DOI: 10.1007/s10162-022-00861-3] [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: 03/17/2020] [Accepted: 07/04/2022] [Indexed: 11/30/2022] Open
Abstract
The relationship between the middle ear acoustic reflex (AR) and inner hair cell (IHC) loss is currently unknown. Given that IHC are believed to convey nearly all acoustic information to the central auditory nervous system, it has been assumed that loss of IHC would significantly impact the AR. To evaluate this relationship, we assessed the presence and amplitude of the AR in chinchillas before and after treatment with carboplatin, an anticancer drug that reliably and selectively destroys IHC in this species. Baseline measures of hearing sensitivity, including auditory brainstem response (ABR) thresholds and distortion product otoacoustic emissions (DPOAE), were assessed and then re-evaluated following carboplatin treatment. Post-carboplatin ABR thresholds and DPOAE were found to be unchanged or slightly elevated; results were consistent with published reports. Our main hypothesis was that loss of IHC would abolish the reflex or significantly reduce its amplitude. Contrary to our hypothesis, the ipsilateral 226-Hz AR continued to be reliably elicited following carboplatin treatment. Post-mortem histological analysis confirmed significant IHC loss (65-85 %), but no measurable loss of outer hair cells (OHCs). Given that loss of IHC alone does not significantly reduce the 226-Hz AR, our results suggest that few IHC are needed to maintain the 226-Hz AR response. These results suggest additional studies are needed to better understand the role of IHC in the reflex arc, present opportunities to further study the reflex pathway, and could change how we use the clinical AR as a potential diagnostic tool for IHC dysfunction, including those related to IHC synaptopathy.
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Affiliation(s)
- Monica Trevino
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Celia Escabi
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Hannah Swanner
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Karen Pawlowski
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
| | - Edward Lobarinas
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX USA
- Callier Center for Communication Disorders, The University of Texas at Dallas, 1966 Inwood Road, Dallas, TX 75235 USA
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Filova I, Pysanenko K, Tavakoli M, Vochyanova S, Dvorakova M, Bohuslavova R, Smolik O, Fabriciova V, Hrabalova P, Benesova S, Valihrach L, Cerny J, Yamoah EN, Syka J, Fritzsch B, Pavlinkova G. ISL1 is necessary for auditory neuron development and contributes toward tonotopic organization. Proc Natl Acad Sci U S A 2022; 119:e2207433119. [PMID: 36074819 PMCID: PMC9478650 DOI: 10.1073/pnas.2207433119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 08/04/2022] [Indexed: 11/18/2022] Open
Abstract
A cardinal feature of the auditory pathway is frequency selectivity, represented in a tonotopic map from the cochlea to the cortex. The molecular determinants of the auditory frequency map are unknown. Here, we discovered that the transcription factor ISL1 regulates the molecular and cellular features of auditory neurons, including the formation of the spiral ganglion and peripheral and central processes that shape the tonotopic representation of the auditory map. We selectively knocked out Isl1 in auditory neurons using Neurod1Cre strategies. In the absence of Isl1, spiral ganglion neurons migrate into the central cochlea and beyond, and the cochlear wiring is profoundly reduced and disrupted. The central axons of Isl1 mutants lose their topographic projections and segregation at the cochlear nucleus. Transcriptome analysis of spiral ganglion neurons shows that Isl1 regulates neurogenesis, axonogenesis, migration, neurotransmission-related machinery, and synaptic communication patterns. We show that peripheral disorganization in the cochlea affects the physiological properties of hearing in the midbrain and auditory behavior. Surprisingly, auditory processing features are preserved despite the significant hearing impairment, revealing central auditory pathway resilience and plasticity in Isl1 mutant mice. Mutant mice have a reduced acoustic startle reflex, altered prepulse inhibition, and characteristics of compensatory neural hyperactivity centrally. Our findings show that ISL1 is one of the obligatory factors required to sculpt auditory structural and functional tonotopic maps. Still, upon Isl1 deletion, the ensuing central plasticity of the auditory pathway does not suffice to overcome developmentally induced peripheral dysfunction of the cochlea.
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Affiliation(s)
- Iva Filova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Kateryna Pysanenko
- Department of Auditory Neuroscience, Institute of Experimental Medicine Czech Academy of Sciences, 14220 Prague, Czechia
| | - Mitra Tavakoli
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Simona Vochyanova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Martina Dvorakova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Romana Bohuslavova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Ondrej Smolik
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Valeria Fabriciova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Petra Hrabalova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Sarka Benesova
- Laboratory of Gene Expression, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Lukas Valihrach
- Laboratory of Gene Expression, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
| | - Jiri Cerny
- Laboratory of Light Microscopy, Institute of Molecular Genetics Czech Academy of Sciences, 14220 Prague, Czechia
| | - Ebenezer N. Yamoah
- Department of Physiology, School of Medicine, University of Nevada, Reno, NV 89557
| | - Josef Syka
- Department of Auditory Neuroscience, Institute of Experimental Medicine Czech Academy of Sciences, 14220 Prague, Czechia
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA 52242-1324
- Department of Otolaryngology, University of Iowa, Iowa City, IA 52242-1324
| | - Gabriela Pavlinkova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology Czech Academy of Sciences, 25250 Vestec, Czechia
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12
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Deans MR. Planar cell polarity signaling guides cochlear innervation. Dev Biol 2022; 486:1-4. [DOI: 10.1016/j.ydbio.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 03/07/2022] [Accepted: 03/13/2022] [Indexed: 01/24/2023]
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13
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Wakizono T, Nakashima H, Yasui T, Noda T, Aoyagi K, Okada K, Yamada Y, Nakagawa T, Nakashima K. Growth factors with valproic acid restore injury-impaired hearing by promoting neuronal regeneration. JCI Insight 2021; 6:139171. [PMID: 34806649 PMCID: PMC8663787 DOI: 10.1172/jci.insight.139171] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Spiral ganglion neurons (SGNs) are primary auditory neurons in the spiral ganglion that transmit sound information from the inner ear to the brain and play an important role in hearing. Impairment of SGNs causes sensorineural hearing loss (SNHL), and it has been thought until now that SGNs cannot be regenerated once lost. Furthermore, no fundamental therapeutic strategy for SNHL has been established other than inserting devices such as hearing aids and cochlear implants. Here we show that the mouse spiral ganglion contains cells that are able to proliferate and indeed differentiate into neurons in response to injury. We suggest that SRY-box transcription factor 2/SRY-box transcription factor 10-double-positive (Sox2/Sox10-double-positive) Schwann cells sequentially started to proliferate, lost Sox10 expression, and became neurons, although the number of new neurons generated spontaneously was very small. To increase the abundance of new neurons, we treated mice with 2 growth factors in combination with valproic acid, which is known to promote neuronal differentiation and survival. This treatment resulted in a dramatic increase in the number of SGNs, accompanied by a partial recovery of the hearing loss induced by injury. Taken together, our findings offer a step toward developing strategies for treatment of SNHL.
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Affiliation(s)
- Takahiro Wakizono
- Department of Stem Cell Biology and Medicine and.,Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | | | - Tetsuro Yasui
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Teppei Noda
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Kei Aoyagi
- Department of Stem Cell Biology and Medicine and.,Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Kanako Okada
- Department of Stem Cell Biology and Medicine and
| | - Yasuhiro Yamada
- Division of Stem Cell Pathology, Center for Experimental Medicine and Systems Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
| | - Takashi Nakagawa
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
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14
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Dunbar RIM, Pearce E, Tarr B, Makdani A, Bamford J, Smith S, McGlone F. Cochlear SGN neurons elevate pain thresholds in response to music. Sci Rep 2021; 11:14547. [PMID: 34267302 PMCID: PMC8282857 DOI: 10.1038/s41598-021-93969-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/28/2021] [Indexed: 11/22/2022] Open
Abstract
The C-tactile (CLTM) peripheral nervous system is involved in social bonding in primates and humans through its capacity to trigger the brain’s endorphin system. Since the mammalian cochlea has an unusually high density of similar neurons (type-II spiral ganglion neurons, SGNs), we hypothesise that their function may have been exploited for social bonding by co-opting head movements in response to music and other rhythmic movements of the head in social contexts. Music provides one of many cultural behavioural mechanisms for ‘virtual grooming’ in that it is used to trigger the endorphin system with many people simultaneously so as to bond both dyadic relationships and large groups. Changes in pain threshold across an activity are a convenient proxy assay for endorphin uptake in the brain, and we use this, in two experiments, to show that pain thresholds are higher when nodding the head than when sitting still.
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Affiliation(s)
- R I M Dunbar
- Department of Experimental Psychology, University of Oxford, Anna Watts Building, Radcliffe Observatory Quarter, Oxford, OX1 6GG, UK.
| | - Eiluned Pearce
- Department of Experimental Psychology, University of Oxford, Anna Watts Building, Radcliffe Observatory Quarter, Oxford, OX1 6GG, UK.,Division of Psychiatry, University College London, London, WC1A 4AA, UK
| | - Bronwyn Tarr
- Institute of Cognitive and Evolutionary Anthropology, University of Oxford, Banbury Road, Oxford, OX2 6PE, UK
| | - Adarsh Makdani
- Research Centre Brain and Behaviour, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Joshua Bamford
- Institute of Cognitive and Evolutionary Anthropology, University of Oxford, Banbury Road, Oxford, OX2 6PE, UK
| | - Sharon Smith
- Research Centre Brain and Behaviour, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Francis McGlone
- Research Centre Brain and Behaviour, Liverpool John Moores University, Liverpool, L3 3AF, UK.,Institute of Psychology, Health and Society, University of Liverpool, Liverpool, UK
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15
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Biswas J, Pijewski RS, Makol R, Miramontes TG, Thompson BL, Kresic LC, Burghard AL, Oliver DL, Martinelli DC. C1ql1 is expressed in adult outer hair cells of the cochlea in a tonotopic gradient. PLoS One 2021; 16:e0251412. [PMID: 33979385 PMCID: PMC8115824 DOI: 10.1371/journal.pone.0251412] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/26/2021] [Indexed: 01/08/2023] Open
Abstract
Hearing depends on the transduction of sounds into neural signals by the inner hair cells of the cochlea. Cochleae also have outer hair cells with unique electromotile properties that increase auditory sensitivity, but they are particularly susceptible to damage by intense noise exposure, ototoxic drugs, and aging. Although the outer hair cells have synapses on afferent neurons that project to the brain, the function of this neuronal circuit is unclear. Here, we created a novel mouse allele that inserts a fluorescent reporter at the C1ql1 locus which revealed gene expression in the outer hair cells and allowed creation of outer hair cell-specific C1ql1 knockout mice. We found that C1ql1 expression in outer hair cells corresponds to areas with the most sensitive frequencies of the mouse audiogram, and that it has an unexpected adolescence-onset developmental timing. No expression was observed in the inner hair cells. Since C1QL1 in the brain is made by neurons, transported anterogradely in axons, and functions in the synaptic cleft, C1QL1 may serve a similar function at the outer hair cell afferent synapse. Histological analyses revealed that C1ql1 conditional knockout cochleae may have reduced outer hair cell afferent synapse maintenance. However, auditory behavioral and physiological assays did not reveal a compelling phenotype. Nonetheless, this study identifies a potentially useful gene expressed in the cochlea and opens the door for future studies aimed at elucidating the function of C1QL1 and the function of the outer hair cell and its afferent neurons.
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Affiliation(s)
- Joyshree Biswas
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Robert S. Pijewski
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Rohit Makol
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
- The Connecticut Institute for the Brain and Cognitive Sciences (IBACS), Storrs, CT, United States of America
| | - Tania G. Miramontes
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Brianna L. Thompson
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Lyndsay C. Kresic
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Alice L. Burghard
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - Douglas L. Oliver
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
| | - David C. Martinelli
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, United States of America
- The Connecticut Institute for the Brain and Cognitive Sciences (IBACS), Storrs, CT, United States of America
- * E-mail:
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16
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Wang H, Wang S, Lu Y, Chen Y, Huang W, Qiu M, Wu H, Hua Y. Cytoarchitecture and innervation of the mouse cochlear amplifier revealed by large-scale volume electron microscopy. J Comp Neurol 2021; 529:2958-2969. [PMID: 33719053 PMCID: PMC8252425 DOI: 10.1002/cne.25137] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/31/2022]
Abstract
In mammalian cochlea, sound‐induced vibration is amplified by a three‐row lattice of Y‐shaped microstructures consisting of electromotile outer hair cell and supporting Deiters cell. This highly organized structure is thought to be essential for hearing of low‐level sounds. Prior studies reported differences in geometry and synaptic innervation of the outer hair cells between rows, but how these fine features are achieved at subcellular level still remains unclear. Using serial block‐face electron microscopy, we acquired few‐hundred‐micron‐sized cytoarchitecture of mouse organ of Corti at nanometer resolution. Structural quantifications were performed on the Y‐shapes as well as afferent and efferent projections to outer hair cells (OHCs). Several new features, which support the previously observed inter‐row heterogeneity, are described. Our result provides structural bases for the gradient of mechanical properties and diverse centrifugal regulation of OHC rows.
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Affiliation(s)
- Haoyu Wang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai, China
| | - Shengxiong Wang
- Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai, China.,Putuo People's Hospital, Tongji University, Shanghai, China
| | - Yan Lu
- Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai, China
| | - Ying Chen
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Wenqing Huang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai, China
| | - Miaoxin Qiu
- Putuo People's Hospital, Tongji University, Shanghai, China
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai, China
| | - Yunfeng Hua
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai, China.,Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.,Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai, China
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17
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Williams ZJ, He JL, Cascio CJ, Woynaroski TG. A review of decreased sound tolerance in autism: Definitions, phenomenology, and potential mechanisms. Neurosci Biobehav Rev 2021; 121:1-17. [PMID: 33285160 PMCID: PMC7855558 DOI: 10.1016/j.neubiorev.2020.11.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/23/2022]
Abstract
Atypical behavioral responses to environmental sounds are common in autistic children and adults, with 50-70 % of this population exhibiting decreased sound tolerance (DST) at some point in their lives. This symptom is a source of significant distress and impairment across the lifespan, contributing to anxiety, challenging behaviors, reduced community participation, and school/workplace difficulties. However, relatively little is known about its phenomenology or neurocognitive underpinnings. The present article synthesizes a large body of literature on the phenomenology and pathophysiology of DST-related conditions to generate a comprehensive theoretical account of DST in autism. Notably, we argue against conceptualizing DST as a unified construct, suggesting that it be separated into three phenomenologically distinct conditions: hyperacusis (the perception of everyday sounds as excessively loud or painful), misophonia (an acquired aversive reaction to specific sounds), and phonophobia (a specific phobia of sound), each responsible for a portion of observed DST behaviors. We further elaborate our framework by proposing preliminary neurocognitive models of hyperacusis, misophonia, and phonophobia that incorporate neurophysiologic findings from studies of autism.
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Affiliation(s)
- Zachary J Williams
- Medical Scientist Training Program, Vanderbilt University School of Medicine, 221 Eskind Biomedical Library and Learning Center, 2209 Garland Ave., Nashville, TN, 37240, United States; Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Medical Center East, Room 8310, Nashville, TN, 37232, United States; Vanderbilt Brain Institute, Vanderbilt University, 7203 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, United States; Frist Center for Autism and Innovation, Vanderbilt University, 2414 Highland Avenue, Suite 115, Nashville, TN, 37212, United States.
| | - Jason L He
- Department of Forensic and Neurodevelopmental Sciences, Sackler Institute for Translational Neurodevelopment, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Strand Building, Strand Campus, Strand, London, WC2R 2LS, London, United Kingdom.
| | - Carissa J Cascio
- Vanderbilt Brain Institute, Vanderbilt University, 7203 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, United States; Frist Center for Autism and Innovation, Vanderbilt University, 2414 Highland Avenue, Suite 115, Nashville, TN, 37212, United States; Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, 2254 Village at Vanderbilt, 1500 21st Ave South, Nashville, TN, 37212, United States; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, 110 Magnolia Cir, Nashville, TN, 37203, United States.
| | - Tiffany G Woynaroski
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, 1215 21st Avenue South, Medical Center East, Room 8310, Nashville, TN, 37232, United States; Vanderbilt Brain Institute, Vanderbilt University, 7203 Medical Research Building III, 465 21st Avenue South, Nashville, TN, 37232, United States; Frist Center for Autism and Innovation, Vanderbilt University, 2414 Highland Avenue, Suite 115, Nashville, TN, 37212, United States; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, 110 Magnolia Cir, Nashville, TN, 37203, United States.
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18
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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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19
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Petitpré C, Bourien J, Wu H, Diuba A, Puel JL, Lallemend F. Genetic and functional diversity of primary auditory afferents. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Noise Induced Hearing Loss and Tinnitus-New Research Developments and Remaining Gaps in Disease Assessment, Treatment, and Prevention. Brain Sci 2020; 10:brainsci10100732. [PMID: 33066210 PMCID: PMC7602100 DOI: 10.3390/brainsci10100732] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/09/2020] [Accepted: 10/10/2020] [Indexed: 01/10/2023] Open
Abstract
Long-term noise exposure often results in noise induced hearing loss (NIHL). Tinnitus, the generation of phantom sounds, can also result from noise exposure, although understanding of its underlying mechanisms are limited. Recent studies, however, are shedding light on the neural processes involved in NIHL and tinnitus, leading to potential new and innovative treatments. This review focuses on the assessment of NIHL, available treatments, and development of new pharmacologic and non-pharmacologic treatments based on recent studies of central auditory plasticity and adaptive changes in hearing. We discuss the mechanisms and maladaptive plasticity of NIHL, neuronal aspects of tinnitus triggers, and mechanisms such as tinnitus-associated neural changes at the cochlear nucleus underlying the generation of tinnitus after noise-induced deafferentation. We include observations from recent studies, including our own studies on associated risks and emerging treatments for tinnitus. Increasing knowledge of neural plasticity and adaptive changes in the central auditory system suggest that NIHL is preventable and transient abnormalities may be reversable, although ongoing research in assessment and early detection of hearing difficulties is still urgently needed. Since no treatment can yet reverse noise-related damage completely, preventative strategies and increased awareness of hearing health are essential.
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21
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Jovanovic S, Milenkovic I. Purinergic Modulation of Activity in the Developing Auditory Pathway. Neurosci Bull 2020; 36:1285-1298. [PMID: 33040238 DOI: 10.1007/s12264-020-00586-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022] Open
Abstract
Purinergic P2 receptors, activated by endogenous ATP, are prominently expressed on neuronal and non-neuronal cells during development of the auditory periphery and central auditory neurons. In the mature cochlea, extracellular ATP contributes to ion homeostasis, and has a protective function against noise exposure. Here, we focus on the modulation of activity by extracellular ATP during early postnatal development of the lower auditory pathway. In mammals, spontaneous patterned activity is conveyed along afferent auditory pathways before the onset of acoustically evoked signal processing. During this critical developmental period, inner hair cells fire bursts of action potentials that are believed to provide a developmental code for synaptic maturation and refinement of auditory circuits, thereby establishing a precise tonotopic organization. Endogenous ATP-release triggers such patterned activity by raising the extracellular K+ concentration and contributes to firing by increasing the excitability of auditory nerve fibers, spiral ganglion neurons, and specific neuron types within the auditory brainstem, through the activation of diverse P2 receptors. We review recent studies that provide new models on the contribution of purinergic signaling to early development of the afferent auditory pathway. Further, we discuss potential future directions of purinergic research in the auditory system.
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Affiliation(s)
- Sasa Jovanovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany
| | - Ivan Milenkovic
- School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany.
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22
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Sun F, Zhou K, Tian KY, Wang J, Qiu JH, Zha DJ. Atrial Natriuretic Peptide Improves Neurite Outgrowth from Spiral Ganglion Neurons In Vitro through a cGMP-Dependent Manner. Neural Plast 2020; 2020:8831735. [PMID: 33193754 PMCID: PMC7643369 DOI: 10.1155/2020/8831735] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 02/06/2023] Open
Abstract
The spiral ganglion neurons (SGNs) are the primary afferent neurons in the spiral ganglion (SG), while their degeneration or loss would cause sensorineural hearing loss. As a cardiac-derived hormone, atrial natriuretic peptide (ANP) plays a critical role in cardiovascular homeostasis through binding to its functional receptors (NPR-A and NPR-C). ANP and its receptors are widely expressed in the mammalian nervous system where they could be implicated in the regulation of multiple neural functions. Although previous studies have provided direct evidence for the presence of ANP and its functional receptors in the inner ear, their presence within the cochlear SG and their regulatory roles during auditory neurotransmission and development remain largely unknown. Based on our previous findings, we investigated the expression patterns of ANP and its receptors in the cochlear SG and dissociated SGNs and determined the influence of ANP on neurite outgrowth in vitro by using organotypic SG explants and dissociated SGN cultures from postnatal rats. We have demonstrated that ANP and its receptors are expressed in neurons within the cochlear SG of postnatal rat, while ANP may promote neurite outgrowth of SGNs via the NPR-A/cGMP/PKG pathway in a dose-dependent manner. These results indicate that ANP would play a role in normal neuritogenesis of SGN during cochlear development and represents a potential therapeutic candidate to enhance regeneration and regrowth of SGN neurites.
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Affiliation(s)
- Fei Sun
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ke Zhou
- Center of Clinical Laboratory Medicine of PLA, Department of Laboratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ke-yong Tian
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jie Wang
- Department of Otolaryngology-Head and Neck Surgery, The Affiliated Children Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710003, China
| | - Jian-hua Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ding-jun Zha
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
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23
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Lee JH, Kang M, Park S, Perez-Flores MC, Zhang XD, Wang W, Gratton MA, Chiamvimonvat N, Yamoah EN. The local translation of KNa in dendritic projections of auditory neurons and the roles of KNa in the transition from hidden to overt hearing loss. Aging (Albany NY) 2019; 11:11541-11564. [PMID: 31812952 PMCID: PMC6932877 DOI: 10.18632/aging.102553] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023]
Abstract
Local and privileged expression of dendritic proteins allows segregation of distinct functions in a single neuron but may represent one of the underlying mechanisms for early and insidious presentation of sensory neuropathy. Tangible characteristics of early hearing loss (HL) are defined in correlation with nascent hidden hearing loss (HHL) in humans and animal models. Despite the plethora of causes of HL, only two prevailing mechanisms for HHL have been identified, and in both cases, common structural deficits are implicated in inner hair cell synapses, and demyelination of the auditory nerve (AN). We uncovered that Na+-activated K+ (KNa) mRNA and channel proteins are distinctly and locally expressed in dendritic projections of primary ANs and genetic deletion of KNa channels (Kcnt1 and Kcnt2) results in the loss of proper AN synaptic function, characterized as HHL, without structural synaptic alterations. We further demonstrate that the local functional synaptic alterations transition from HHL to increased hearing-threshold, which entails changes in global Ca2+ homeostasis, activation of caspases 3/9, impaired regulation of inositol triphosphate receptor 1 (IP3R1), and apoptosis-mediated neurodegeneration. Thus, the present study demonstrates how local synaptic dysfunction results in an apparent latent pathological phenotype (HHL) and, if undetected, can lead to overt HL. It also highlights, for the first time, that HHL can precede structural synaptic dysfunction and AN demyelination. The stepwise cellular mechanisms from HHL to canonical HL are revealed, providing a platform for intervention to prevent lasting and irreversible age-related hearing loss (ARHL).
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Affiliation(s)
- Jeong Han Lee
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA
| | - Mincheol Kang
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA
| | - Seojin Park
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA
| | - Maria C Perez-Flores
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA
| | - Xiao-Dong Zhang
- Department of Internal Medicine, Division of Cardiology, University of California Davis, Davis, CA 95616, USA
| | - Wenying Wang
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA
| | - Michael Anne Gratton
- Department of Otolaryngology, Head and Neck Surgery, Washington University St. Louis, St. Louis, MO 63110, USA
| | - Nipavan Chiamvimonvat
- Department of Internal Medicine, Division of Cardiology, University of California Davis, Davis, CA 95616, USA
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV 89557, USA
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24
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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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Bertram S, Roll L, Reinhard J, Groß K, Dazert S, Faissner A, Volkenstein S. Pleiotrophin increases neurite length and number of spiral ganglion neurons in vitro. Exp Brain Res 2019; 237:2983-2993. [PMID: 31515588 DOI: 10.1007/s00221-019-05644-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/03/2019] [Indexed: 11/28/2022]
Abstract
Acoustic trauma, aging, genetic defects or ototoxic drugs are causes for sensorineural hearing loss involving sensory hair cell death and secondary degeneration of spiral ganglion neurons. Auditory implants are the only available therapy for severe to profound sensorineural hearing loss when hearing aids do not provide a sufficient speech discrimination anymore. Neurotrophic factors represent potential therapeutic candidates to improve the performance of cochlear implants (CIs) by the support of spiral ganglion neurons (SGNs). Here, we investigated the effect of pleiotrophin (PTN), a well-described neurotrophic factor for different types of neurons that is expressed in the postnatal mouse cochlea. PTN knockout mice exhibit severe deficits in auditory brainstem responses, which indicates the importance of PTN in inner ear development and function and makes it a promising candidate to support SGNs. Using organotypic explants and dissociated SGN cultures, we investigated the influence of PTN on the number of neurons, neurite number and neurite length. PTN significantly increased the number and neurite length of dissociated SGNs. We further verified the expression of important PTN-associated receptors in the SG. mRNA of anaplastic lymphoma kinase, αv integrin, β3 integrin, receptor protein tyrosine phosphatase β/ζ, neuroglycan C, low-density lipoprotein receptor-related protein 1 and syndecan 3 was detected in the inner ear. These results suggest that PTN may be a novel candidate to improve sensorineural hearing loss treatment in the future.
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Affiliation(s)
- Sebastian Bertram
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth-Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany
| | - Lars Roll
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Jacqueline Reinhard
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Katharina Groß
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Stefan Dazert
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth-Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstr. 150, 44801, Bochum, Germany
| | - Stefan Volkenstein
- Department of Otorhinolaryngology, Head and Neck Surgery, St. Elisabeth-Hospital, Ruhr-University Bochum, Bleichstr. 15, 44787, Bochum, Germany.
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Frizzled3 and Frizzled6 Cooperate with Vangl2 to Direct Cochlear Innervation by Type II Spiral Ganglion Neurons. J Neurosci 2019; 39:8013-8023. [PMID: 31462532 DOI: 10.1523/jneurosci.1740-19.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 08/20/2019] [Accepted: 08/23/2019] [Indexed: 11/21/2022] Open
Abstract
Type II spiral ganglion neurons provide afferent innervation to outer hair cells of the cochlea and are proposed to have nociceptive functions important for auditory function and homeostasis. These neurons are anatomically distinct from other classes of spiral ganglion neurons because they extend a peripheral axon beyond the inner hair cells that subsequently makes a distinct 90 degree turn toward the cochlear base. As a result, patterns of outer hair cell innervation are coordinated with the tonotopic organization of the cochlea. Previously, it was shown that peripheral axon turning is directed by a nonautonomous function of the core planar cell polarity (PCP) protein VANGL2. We demonstrate using mice of either sex that Fzd3 and Fzd6 similarly regulate axon turning, are functionally redundant with each other, and that Fzd3 genetically interacts with Vangl2 to guide this process. FZD3 and FZD6 proteins are asymmetrically distributed along the basolateral wall of cochlear-supporting cells, and are required to promote or maintain the asymmetric distribution of VANGL2 and CELSR1. These data indicate that intact PCP complexes formed between cochlear-supporting cells are required for the nonautonomous regulation of axon pathfinding. Consistent with this, in the absence of PCP signaling, peripheral axons turn randomly and often project toward the cochlear apex. Additional analyses of Porcn mutants in which WNT secretion is reduced suggest that noncanonical WNT signaling establishes or maintains PCP signaling in this context. A deeper understanding of these mechanisms is necessary for repairing auditory circuits following acoustic trauma or promoting cochlear reinnervation during regeneration-based deafness therapies.SIGNIFICANCE STATEMENT Planar cell polarity (PCP) signaling has emerged as a complementary mechanism to classical axon guidance in regulating axon track formation, axon outgrowth, and neuronal polarization. The core PCP proteins are also required for auditory circuit assembly, and coordinate hair cell innervation with the tonotopic organization of the cochlea. This is a non-cell-autonomous mechanism that requires the formation of PCP protein complexes between cochlear-supporting cells located along the trajectory of growth cone navigation. These findings are significant because they demonstrate how the fidelity of auditory circuit formation is ensured during development, and provide a mechanism by which PCP proteins may regulate axon outgrowth and guidance in the CNS.
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Sánchez-Guardado LÓ, Puelles L, Hidalgo-Sánchez M. Origin of acoustic-vestibular ganglionic neuroblasts in chick embryos and their sensory connections. Brain Struct Funct 2019; 224:2757-2774. [PMID: 31396696 DOI: 10.1007/s00429-019-01934-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/31/2019] [Indexed: 01/03/2023]
Abstract
The inner ear is a complex three-dimensional sensory structure with auditory and vestibular functions. It originates from the otic placode, which generates the sensory elements of the membranous labyrinth and all the ganglionic neuronal precursors. Neuroblast specification is the first cell differentiation event. In the chick, it takes place over a long embryonic period from the early otic cup stage to at least stage HH25. The differentiating ganglionic neurons attain a precise innervation pattern with sensory patches, a process presumably governed by a network of dendritic guidance cues which vary with the local micro-environment. To study the otic neurogenesis and topographically-ordered innervation pattern in birds, a quail-chick chimaeric graft technique was used in accordance with a previously determined fate-map of the otic placode. Each type of graft containing the presumptive domain of topologically-arranged placodal sensory areas was shown to generate neuroblasts. The differentiated grafted neuroblasts established dendritic contacts with a variety of sensory patches. These results strongly suggest that, rather than reverse-pathfinding, the relevant role in otic dendritic process guidance is played by long-range diffusing molecules.
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Affiliation(s)
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, E30100, Murcia, Spain.,Instituto Murciano de Investigaciones Biosanitarias (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Matías Hidalgo-Sánchez
- Department of Cell Biology, School of Science, University of Extremadura, E06071, Badajoz, Spain.
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Köles L, Szepesy J, Berekméri E, Zelles T. Purinergic Signaling and Cochlear Injury-Targeting the Immune System? Int J Mol Sci 2019; 20:ijms20122979. [PMID: 31216722 PMCID: PMC6627352 DOI: 10.3390/ijms20122979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 02/06/2023] Open
Abstract
Hearing impairment is the most common sensory deficit, affecting more than 400 million people worldwide. Sensorineural hearing losses currently lack any specific or efficient pharmacotherapy largely due to the insufficient knowledge of the pathomechanism. Purinergic signaling plays a substantial role in cochlear (patho)physiology. P2 (ionotropic P2X and the metabotropic P2Y) as well as adenosine receptors expressed on cochlear sensory and non-sensory cells are involved mostly in protective mechanisms of the cochlea. They are implicated in the sensitivity adjustment of the receptor cells by a K+ shunt and can attenuate the cochlear amplification by modifying cochlear micromechanics. Cochlear blood flow is also regulated by purines. Here, we propose to comprehend this field with the purine-immune interactions in the cochlea. The role of harmful immune mechanisms in sensorineural hearing losses has been emerging in the horizon of cochlear pathologies. In addition to decreasing hearing sensitivity and increasing cochlear blood supply, influencing the immune system can be the additional avenue for pharmacological targeting of purinergic signaling in the cochlea. Elucidating this complexity of purinergic effects on cochlear functions is necessary and it can result in development of new therapeutic approaches in hearing disabilities, especially in the noise-induced ones.
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Affiliation(s)
- László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Judit Szepesy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
| | - Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Ecology, University of Veterinary Medicine, H-1078 Budapest, Hungary.
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary.
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary.
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29
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GSK3 regulates hair cell fate in the developing mammalian cochlea. Dev Biol 2019; 453:191-205. [PMID: 31185200 DOI: 10.1016/j.ydbio.2019.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 06/07/2019] [Accepted: 06/07/2019] [Indexed: 12/27/2022]
Abstract
The development of asymmetric patterns along biologically relevant axes is a hallmark of many vertebrate organs or structures. One example is the sensory epithelium of the mammalian auditory system. Two distinct types of mechanosensory hair cells (inner and outer) and at least six types of associated supporting cells are precisely and asymmetrically arrayed along the radial (medial-lateral) axis of the cochlear spiral. Immunolabeling of developing cochleae indicates differential expression of Glycogen synthase kinase 3β (GSK3β) along the same axis. To determine whether GSK3β plays a role in specification of cell fates along the medial-lateral axis, GSK3 activity was blocked pharmacologically in cochlear explants. Results indicate significant changes in both the number of hair cells and in the specification of hair cell phenotypes. The overall number of inner hair cells increased as a result of both a shift in the medial boundary between sensory and non-sensory regions of the cochlea and a change in the specification of inner and outer hair cell phenotypes. Previous studies have inhibited GSK3 as a method to examine effects of canonical Wnt signaling. However, quantification of changes in Wnt pathway target genes in GSK3-inhibited cochleae, and treatment with more specific Wnt agonists, indicated that the Wnt pathway is not activated. Instead, expression of Bmp4 in a population of GSK3β-expressing cells was shown to be down-regulated. Finally, addition of BMP4 to GSK3-inhibited cochleae achieved a partial rescue of the hair cell phenotype. These results demonstrate a role for GSK3β in the specification of cellular identities along the medial-lateral axis of the cochlea and provide evidence for a positive role for GSK3β in the expression of Bmp4.
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Coate TM, Scott MK, Gurjar MC. Current concepts in cochlear ribbon synapse formation. Synapse 2019; 73:e22087. [PMID: 30592086 PMCID: PMC6573016 DOI: 10.1002/syn.22087] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022]
Abstract
In mammals, hair cells and spiral ganglion neurons (SGNs) in the cochlea together are sophisticated "sensorineural" structures that transduce auditory information from the outside world into the brain. Hair cells and SGNs are joined by glutamatergic ribbon-type synapses composed of a molecular machinery rivaling in complexity the mechanoelectric transduction components found at the apical side of the hair cell. The cochlear hair cell ribbon synapse has received much attention lately because of recent and important findings related to its damage (sometimes termed "synaptopathy") as a result of noise overexposure. During development, ribbon synapses between type I SGNs and inner hair cells form in the time window between birth and hearing onset and is a process coordinated with type I SGN myelination, spontaneous activity, synaptic pruning, and innervation by efferents. In this review, we highlight new findings regarding the diversity of type I SGNs and inner hair cell synapses, and the molecular mechanisms of selective hair cell targeting. Also discussed are cell adhesion molecules and protein constituents of the ribbon synapse, and how these factors participate in ribbon synapse formation. We also note interesting new insights into the morphological development of type II SGNs, and the potential for cochlear macrophages as important players in protecting SGNs. We also address recent studies demonstrating that the structural and physiological profiles of the type I SGNs do not reach full maturity until weeks after hearing onset, suggesting a protracted development that is likely modulated by activity.
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Affiliation(s)
- Thomas M. Coate
- Georgetown University, Department of Biology, 37th and O St. NW. Washington, DC. 20007. USA
| | - M. Katie Scott
- Department of Biological Sciences and Purdue Institute of Integrative Neuroscience, Purdue University, West Lafayette, Indiana 47907. USA
| | - Mansa C. Gurjar
- Georgetown University, Department of Biology, 37th and O St. NW. Washington, DC. 20007. USA
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Liu W, Wang X, Wang M, Wang H. Protection of Spiral Ganglion Neurons and Prevention of Auditory Neuropathy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1130:93-107. [DOI: 10.1007/978-981-13-6123-4_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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32
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Fritzsch B, Elliott KL, Pavlinkova G. Primary sensory map formations reflect unique needs and molecular cues specific to each sensory system. F1000Res 2019; 8:F1000 Faculty Rev-345. [PMID: 30984379 PMCID: PMC6439788 DOI: 10.12688/f1000research.17717.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/21/2019] [Indexed: 12/21/2022] Open
Abstract
Interaction with the world around us requires extracting meaningful signals to guide behavior. Each of the six mammalian senses (olfaction, vision, somatosensation, hearing, balance, and taste) has a unique primary map that extracts sense-specific information. Sensory systems in the periphery and their target neurons in the central nervous system develop independently and must develop specific connections for proper sensory processing. In addition, the regulation of sensory map formation is independent of and prior to central target neuronal development in several maps. This review provides an overview of the current level of understanding of primary map formation of the six mammalian senses. Cell cycle exit, combined with incompletely understood molecules and their regulation, provides chemoaffinity-mediated primary maps that are further refined by activity. The interplay between cell cycle exit, molecular guidance, and activity-mediated refinement is the basis of dominance stripes after redundant organ transplantations in the visual and balance system. A more advanced level of understanding of primary map formation could benefit ongoing restoration attempts of impaired senses by guiding proper functional connection formations of restored sensory organs with their central nervous system targets.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, USA
| | | | - Gabriela Pavlinkova
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
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OHC-TRECK: A Novel System Using a Mouse Model for Investigation of the Molecular Mechanisms Associated with Outer Hair Cell Death in the Inner Ear. Sci Rep 2019; 9:5285. [PMID: 30918314 PMCID: PMC6437180 DOI: 10.1038/s41598-019-41711-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 03/15/2019] [Indexed: 12/20/2022] Open
Abstract
Outer hair cells (OHCs) are responsible for the amplification of sound, and the death of these cells leads to hearing loss. Although the mechanisms for sound amplification and OHC death have been well investigated, the effects on the cochlea after OHC death are poorly understood. To study the consequences of OHC death, we established an OHC knockout system using a novel mouse model, Prestin-hDTR, which uses the prestin promoter to express the human diphtheria toxin (DT) receptor gene (hDTR). Administration of DT to adult Prestin-hDTR mice results in the depletion of almost all OHCs without significant damage to other cochlear and vestibular cells, suggesting that this system is an effective tool for the analysis of how other cells in the cochlea and vestibula are affected after OHC death. To evaluate the changes in the cochlea after OHC death, we performed differential gene expression analysis between the untreated and DT-treated groups of wild-type and Prestin-hDTR mice. This analysis revealed that genes associated with inflammatory/immune responses were significantly upregulated. Moreover, we found that several genes linked to hearing loss were strongly downregulated by OHC death. Together, these results suggest that this OHC knockout system is a useful tool to identify biomarkers associated with OHC death.
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Harley RJ, Murdy JP, Wang Z, Kelly MC, Ropp TJF, Park SH, Maness PF, Manis PB, Coate TM. Neuronal cell adhesion molecule (NrCAM) is expressed by sensory cells in the cochlea and is necessary for proper cochlear innervation and sensory domain patterning during development. Dev Dyn 2018; 247:934-950. [PMID: 29536590 PMCID: PMC6105381 DOI: 10.1002/dvdy.24629] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 03/06/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND In the cochlea, auditory development depends on precise patterns of innervation by afferent and efferent nerve fibers, as well as a stereotyped arrangement of hair and supporting cells. Neuronal cell adhesion molecule (NrCAM) is a homophilic cell adhesion molecule that controls diverse aspects of nervous system development, but the function of NrCAM in cochlear development is not well understood. RESULTS Throughout cochlear innervation, NrCAM is detectable on spiral ganglion neuron (SGN) afferent and olivocochlear efferent fibers, and on the membranes of developing hair and supporting cells. Neonatal Nrcam-null cochleae show errors in type II SGN fasciculation, reduced efferent innervation, and defects in the stereotyped packing of hair and supporting cells. Nrcam loss also leads to dramatic changes in the profiles of presynaptic afferent and efferent synaptic markers at the time of hearing onset. Despite these numerous developmental defects, Nrcam-null adults do not show defects in auditory acuity, and by postnatal day 21, the developmental deficits in ribbon synapse distribution and sensory domain structure appear to have been corrected. CONCLUSIONS NrCAM is expressed by several neural and sensory epithelial subtypes within the developing cochlea, and the loss of Nrcam confers numerous, but nonpermanent, developmental defects in innervation and sensory domain patterning. Developmental Dynamics 247:934-950, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Randall J. Harley
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Joseph P. Murdy
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Zhirong Wang
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Michael C. Kelly
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Tessa-Jonne F. Ropp
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill, B251 Marsico Hall, CB#7070, 125 Mason Farm Rd., Chapel Hill, NC 27599, USA
| | - SeHoon H. Park
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Patricia F. Maness
- Department of Biochemistry and Biophysics, The University of North Carolina School of Medicine, 120 Mason Farm Rd., suite 3020, CB#7260, Chapel Hill, NC 27599, USA
| | - Paul B. Manis
- Department of Otolaryngology/Head and Neck Surgery and Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, B027 Marsico Hall, CB#7070. 125 Mason Farm Rd., Chapel Hill, NC 27599
| | - Thomas M. Coate
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
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35
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Fitzakerley JL, Trachte GJ. Genetics of guanylyl cyclase pathways in the cochlea and their influence on hearing. Physiol Genomics 2018; 50:780-806. [PMID: 29958079 DOI: 10.1152/physiolgenomics.00056.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although hearing loss is the most common sensory deficit in Western societies, there are no successful pharmacological treatments for this disorder. Recent experiments have demonstrated that manipulation of intracellular cyclic guanosine monophosphate (cGMP) concentrations can have both beneficial and harmful effects on hearing. In this review, we will examine the role of cGMP as a key second messenger involved in many aspects of cochlear function and discuss the known functions of downstream effectors of cGMP in sound processing. The nitric oxide-stimulated soluble guanylyl cyclase system (sGC) and the two natriuretic peptide-stimulated particulate GCs (pGCs) will be more extensively covered because they have been studied most thoroughly. The cochlear GC systems are attractive targets for medical interventions that improve hearing while simultaneously representing an under investigated source of sensorineural hearing loss.
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Affiliation(s)
- Janet L Fitzakerley
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
| | - George J Trachte
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
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36
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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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