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Dias JW, McClaskey CM, Alvey AP, Lawson A, Matthews LJ, Dubno JR, Harris KC. Effects of age and noise exposure history on auditory nerve response amplitudes: A systematic review, study, and meta-analysis. Hear Res 2024; 447:109010. [PMID: 38744019 PMCID: PMC11135078 DOI: 10.1016/j.heares.2024.109010] [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: 03/08/2024] [Revised: 04/08/2024] [Accepted: 04/18/2024] [Indexed: 05/16/2024]
Abstract
Auditory nerve (AN) function has been hypothesized to deteriorate with age and noise exposure. Here, we perform a systematic review of published studies and find that the evidence for age-related deficits in AN function is largely consistent across the literature, but there are inconsistent findings among studies of noise exposure history. Further, evidence from animal studies suggests that the greatest deficits in AN response amplitudes are found in noise-exposed aged mice, but a test of the interaction between effects of age and noise exposure on AN function has not been conducted in humans. We report a study of our own examining differences in the response amplitude of the compound action potential N1 (CAP N1) between younger and older adults with and without a self-reported history of noise exposure in a large sample of human participants (63 younger adults 18-30 years of age, 103 older adults 50-86 years of age). CAP N1 response amplitudes were smaller in older than younger adults. Noise exposure history did not appear to predict CAP N1 response amplitudes, nor did the effect of noise exposure history interact with age. We then incorporated our results into two meta-analyses of published studies of age and noise exposure history effects on AN response amplitudes in neurotypical human samples. The meta-analyses found that age effects across studies are robust (r = -0.407), but noise exposure effects are weak (r = -0.152). We conclude that noise exposure effects may be highly variable depending on sample characteristics, study design, and statistical approach, and researchers should be cautious when interpreting results. The underlying pathology of age-related and noise-induced changes in AN function are difficult to determine in living humans, creating a need for longitudinal studies of changes in AN function across the lifespan and histological examination of the AN from temporal bones collected post-mortem.
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Affiliation(s)
- James W Dias
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States.
| | - Carolyn M McClaskey
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - April P Alvey
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Abigail Lawson
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Lois J Matthews
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Judy R Dubno
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
| | - Kelly C Harris
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, United States
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2
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Hemachandran S, Hu N, Kane CJ, Green SH. Cyclic AMP signaling promotes regeneration of cochlear synapses after excitotoxic or noise trauma. Front Cell Neurosci 2024; 18:1363219. [PMID: 38694536 PMCID: PMC11061447 DOI: 10.3389/fncel.2024.1363219] [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: 12/30/2023] [Accepted: 03/27/2024] [Indexed: 05/04/2024] Open
Abstract
Introduction Cochlear afferent synapses connecting inner hair cells to spiral ganglion neurons are susceptible to excitotoxic trauma on exposure to loud sound, resulting in a noise-induced cochlear synaptopathy (NICS). Here we assessed the ability of cyclic AMP-dependent protein kinase (PKA) signaling to promote cochlear synapse regeneration, inferred from its ability to promote axon regeneration in axotomized CNS neurons, another system refractory to regeneration. Methods We mimicked NICS in vitro by applying a glutamate receptor agonist, kainic acid (KA) to organotypic cochlear explant cultures and experimentally manipulated cAMP signaling to determine whether PKA could promote synapse regeneration. We then delivered the cAMP phosphodiesterase inhibitor rolipram via implanted subcutaneous minipumps in noise-exposed CBA/CaJ mice to test the hypothesis that cAMP signaling could promote cochlear synapse regeneration in vivo. Results We showed that the application of the cell membrane-permeable cAMP agonist 8-cpt-cAMP or the cAMP phosphodiesterase inhibitor rolipram promotes significant regeneration of synapses in vitro within twelve hours after their destruction by KA. This is independent of neurotrophin-3, which also promotes synapse regeneration. Moreover, of the two independent signaling effectors activated by cAMP - the cAMP Exchange Protein Activated by cAMP and the cAMP-dependent protein kinase - it is the latter that mediates synapse regeneration. Finally, we showed that systemic delivery of rolipram promotes synapse regeneration in vivo following NICS. Discussion In vitro experiments show that cAMP signaling promotes synapse regeneration after excitotoxic destruction of cochlear synapses and does so via PKA signaling. The cAMP phosphodiesterase inhibitor rolipram promotes synapse regeneration in vivo in noise-exposed mice. Systemic administration of rolipram or similar compounds appears to provide a minimally invasive therapeutic approach to reversing synaptopathy post-noise.
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Affiliation(s)
| | | | | | - Steven H. Green
- Department of Biology, University of Iowa, Iowa City, IA, United States
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3
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Dias JW, McClaskey CM, Alvey AP, Lawson A, Matthews LJ, Dubno JR, Harris KC. Effects of Age and Noise Exposure History on Auditory Nerve Response Amplitudes: A Systematic Review, Study, and Meta-Analysis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585882. [PMID: 38585917 PMCID: PMC10996537 DOI: 10.1101/2024.03.20.585882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Auditory nerve (AN) function has been hypothesized to deteriorate with age and noise exposure. Here, we perform a systematic review of published studies and find that the evidence for age-related deficits in AN function is largely consistent across the literature, but there are inconsistent findings among studies of noise exposure history. Further, evidence from animal studies suggests that the greatest deficits in AN response amplitudes are found in noise-exposed aged mice, but a test of the interaction between effects of age and noise exposure on AN function has not been conducted in humans. We report a study of our own examining differences in the response amplitude of the compound action potential N1 (CAP N1) between younger and older adults with and without a self-reported history of noise exposure in a large sample of human participants (63 younger adults 18-30 years of age, 103 older adults 50-86 years of age). CAP N1 response amplitudes were smaller in older than younger adults. Noise exposure history did not appear to predict CAP N1 response amplitudes, nor did the effect of noise exposure history interact with age. We then incorporated our results into two meta-analyses of published studies of age and noise exposure history effects on AN response amplitudes in neurotypical human samples. The meta-analyses found that age effects across studies are robust (r=-0.407), but noise-exposure effects are weak (r=-0.152). We conclude that noise-exposure effects may be highly variable depending on sample characteristics, study design, and statistical approach, and researchers should be cautious when interpreting results. The underlying pathology of age-related and noise-induced changes in AN function are difficult to determine in living humans, creating a need for longitudinal studies of changes in AN function across the lifespan and histological examination of the AN from temporal bones collected post-mortem.
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Affiliation(s)
- James W Dias
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Carolyn M McClaskey
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - April P Alvey
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Abigail Lawson
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Lois J Matthews
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Judy R Dubno
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
| | - Kelly C Harris
- Medical University of South Carolina Department of Otolaryngology - Head and Neck Surgery
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4
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Liu J, Stohl J, Overath T. Hidden hearing loss: Fifteen years at a glance. Hear Res 2024; 443:108967. [PMID: 38335624 DOI: 10.1016/j.heares.2024.108967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 01/15/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
Hearing loss affects approximately 18% of the population worldwide. Hearing difficulties in noisy environments without accompanying audiometric threshold shifts likely affect an even larger percentage of the global population. One of the potential causes of hidden hearing loss is cochlear synaptopathy, the loss of synapses between inner hair cells (IHC) and auditory nerve fibers (ANF). These synapses are the most vulnerable structures in the cochlea to noise exposure or aging. The loss of synapses causes auditory deafferentation, i.e., the loss of auditory afferent information, whose downstream effect is the loss of information that is sent to higher-order auditory processing stages. Understanding the physiological and perceptual effects of this early auditory deafferentation might inform interventions to prevent later, more severe hearing loss. In the past decade, a large body of work has been devoted to better understand hidden hearing loss, including the causes of hidden hearing loss, their corresponding impact on the auditory pathway, and the use of auditory physiological measures for clinical diagnosis of auditory deafferentation. This review synthesizes the findings from studies in humans and animals to answer some of the key questions in the field, and it points to gaps in knowledge that warrant more investigation. Specifically, recent studies suggest that some electrophysiological measures have the potential to function as indicators of hidden hearing loss in humans, but more research is needed for these measures to be included as part of a clinical test battery.
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Affiliation(s)
- Jiayue Liu
- Department of Psychology and Neuroscience, Duke University, Durham, USA.
| | - Joshua Stohl
- North American Research Laboratory, MED-EL Corporation, Durham, USA
| | - Tobias Overath
- Department of Psychology and Neuroscience, Duke University, Durham, USA
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Bizup B, Brutsaert S, Cunningham CL, Thathiah A, Tzounopoulos T. Cochlear zinc signaling dysregulation is associated with noise-induced hearing loss, and zinc chelation enhances cochlear recovery. Proc Natl Acad Sci U S A 2024; 121:e2310561121. [PMID: 38354264 PMCID: PMC10895357 DOI: 10.1073/pnas.2310561121] [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: 06/22/2023] [Accepted: 01/08/2024] [Indexed: 02/16/2024] Open
Abstract
Exposure to loud noise triggers sensory organ damage and degeneration that, in turn, leads to hearing loss. Despite the troublesome impact of noise-induced hearing loss (NIHL) in individuals and societies, treatment strategies that protect and restore hearing are few and insufficient. As such, identification and mechanistic understanding of the signaling pathways involved in NIHL are required. Biological zinc is mostly bound to proteins, where it plays major structural or catalytic roles; however, there is also a pool of unbound, mobile (labile) zinc. Labile zinc is mostly found in vesicles in secretory tissues, where it is released and plays a critical signaling role. In the brain, labile zinc fine-tunes neurotransmission and sensory processing. However, injury-induced dysregulation of labile zinc signaling contributes to neurodegeneration. Here, we tested whether zinc dysregulation occurs and contributes to NIHL in mice. We found that ZnT3, the vesicular zinc transporter responsible for loading zinc into vesicles, is expressed in cochlear hair cells and the spiral limbus, with labile zinc also present in the same areas. Soon after noise trauma, ZnT3 and zinc levels are significantly increased, and their subcellular localization is vastly altered. Disruption of zinc signaling, either via ZnT3 deletion or pharmacological zinc chelation, mitigated NIHL, as evidenced by enhanced auditory brainstem responses, distortion product otoacoustic emissions, and number of hair cell synapses. These data reveal that noise-induced zinc dysregulation is associated with cochlear dysfunction and recovery after NIHL, and point to zinc chelation as a potential treatment for mitigating NIHL.
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Affiliation(s)
- Brandon Bizup
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15261
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Sofie Brutsaert
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Christopher L Cunningham
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15261
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Amantha Thathiah
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Thanos Tzounopoulos
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA 15261
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261
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6
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Xie R, Wang M, Zhang C. Mechanisms of age-related hearing loss at the auditory nerve central synapses and postsynaptic neurons in the cochlear nucleus. Hear Res 2024; 442:108935. [PMID: 38113793 PMCID: PMC10842789 DOI: 10.1016/j.heares.2023.108935] [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: 10/11/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/21/2023]
Abstract
Sound information is transduced from mechanical vibration to electrical signals in the cochlea, conveyed to and further processed in the brain to form auditory perception. During the process, spiral ganglion neurons (SGNs) are the key cells that connect the peripheral and central auditory systems by receiving information from hair cells in the cochlea and transmitting it to neurons of the cochlear nucleus (CN). Decades of research in the cochlea greatly improved our understanding of SGN function under normal and pathological conditions, especially about the roles of different subtypes of SGNs and their peripheral synapses. However, it remains less clear how SGN central terminals or auditory nerve (AN) synapses connect to CN neurons, and ultimately how peripheral pathology links to structural alterations and functional deficits in the central auditory nervous system. This review discusses recent progress about the morphological and physiological properties of different subtypes of AN synapses and associated postsynaptic CN neurons, their changes during aging, and the potential mechanisms underlying age-related hearing loss.
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Affiliation(s)
- Ruili Xie
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA; Department of Neuroscience, The Ohio State University, 420W 12th Ave, Columbus, OH 43210, USA.
| | - Meijian Wang
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA
| | - Chuangeng Zhang
- Department of Otolaryngology, The Ohio State University, 420 W 12th Ave, Columbus OH 43210, USA
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Gross J, Knipper M, Mazurek B. Candidate Key Proteins in Tinnitus: A Bioinformatic Study of Synaptic Transmission in Spiral Ganglion Neurons. Cell Mol Neurobiol 2023; 43:4189-4207. [PMID: 37736859 PMCID: PMC10661836 DOI: 10.1007/s10571-023-01405-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 08/24/2023] [Indexed: 09/23/2023]
Abstract
To study key proteins associated with changes in synaptic transmission in the spiral ganglion in tinnitus, we build three gene lists from the GeneCard database: 1. Perception of sound (PoS), 2. Acoustic stimulation (AcouStim), and 3. Tinnitus (Tin). Enrichment analysis by the DAVID database resulted in similar Gene Ontology (GO) terms for cellular components in all gene lists, reflecting synaptic structures known to be involved in auditory processing. The STRING protein-protein interaction (PPI) network and the Cytoscape data analyzer were used to identify the top two high-degree proteins (HDPs) and their high-score interaction proteins (HSIPs) identified by the combined score (CS) of the corresponding edges. The top two protein pairs (key proteins) for the PoS are BDNF-GDNF and OTOF-CACNA1D and for the AcouStim process BDNF-NTRK2 and TH-CALB1. The Tin process showed BDNF and NGF as HDPs, with high-score interactions with NTRK1 and NGFR at a comparable level. Compared to the PoS and AcouStim process, the number of HSIPs of key proteins (CS > 90. percentile) increases strongly in Tin. In the PoS and AcouStim networks, BDNF receptor signaling is the dominant pathway, and in the Tin network, the NGF-signaling pathway is of similar importance. Key proteins and their HSIPs are good indicators of biological processes and of signaling pathways characteristic for the normal hearing on the one hand and tinnitus on the other.
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Affiliation(s)
- Johann Gross
- Tinnitus Center, Charité-Universitätsmedizin Berlin, Berlin, Germany.
- Leibniz Society of Science Berlin, Berlin, Germany.
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
- Leibniz Society of Science Berlin, Berlin, Germany
| | - Birgit Mazurek
- Tinnitus Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Hu S, Sun Q, Xu F, Jiang N, Gao J. Age-related hearing loss and its potential drug candidates: a systematic review. Chin Med 2023; 18:121. [PMID: 37730634 PMCID: PMC10512576 DOI: 10.1186/s13020-023-00825-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/25/2023] [Indexed: 09/22/2023] Open
Abstract
BACKGROUND Age-related hearing loss (ARHL) is one of the main illnesses afflicting the aged population and has a significant negative impact on society, economy, and health. However, there is presently no appropriate therapeutic treatment of ARHL due to the absence of comprehensive trials. OBJECTIVES The goal of this review is to systematically evaluate and analyze recent statistics on the pathologic classifications, risk factors, treatment strategies, and drug candidates of ARHL, including that from traditional Chinese medicine (TCM), to provide potential new approaches for preventing and treating ARHL. METHODS Literature related to ARHL was conducted in databases such as PubMed, WOS, China National Knowledge Infrastructure (CNKI), and Wanfang from the establishment of the database to Jan, 2023. The pathology, causal factor, pathophysiological mechanism, treatment strategy, and the drug candidate of ARHL were extracted and pooled for synthesis. RESULTS Many hypotheses about the etiology of ARHL are based on genetic and environmental elements. Most of the current research on the pathology of ARHL focuses on oxidative damage, mitochondrial dysfunction, inflammation, cochlear blood flow, ion homeostasis, etc. In TCM, herbs belonging to the kidney, lung, and liver meridians exhibit good hearing protection. Seven herbs belonging to the kidney meridian, 9 belonging to the lung meridian, and 4 belonging to the liver meridian were ultimately retrieved in this review, such as Polygonum multiflorum Thunb., Panax ginseng C.A. Mey, and Pueraria lobata (Willd.) Ohwi. Their active compounds, 2,3,4',5-Tetrahydroxystilbene-2-O-D-glucoside, ginsenoside Rb1, and puerarin, may act as the molecular substance for their anti-ARHL efficacy, and show anti-oxidative, neuroprotective, anti-inflammatory, anti-apoptotic, or mitochondrial protective effects. CONCLUSION Anti-oxidants, modulators of mitochondrial function, anti-inflammation agents, vasodilators, K+ channel openers, Ca2+ channel blockers, JNK inhibitors, and nerve growth factors/neurotrophic factors all contribute to hearing protection, and herbs are an important source of potential anti-ARHL drugs.
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Affiliation(s)
- Shiyu Hu
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, People's Republic of China
| | - Qingru Sun
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, People's Republic of China
| | - Fei Xu
- School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, People's Republic of China
| | - Ninghua Jiang
- Department of Pharmacy, The Second Affiliated Hospital of Jiaxing University, Jiaxing, 314000, Zhejiang, People's Republic of China
| | - Jianli Gao
- School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, People's Republic of China.
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Fang Q, Wei Y, Zhang Y, Cao W, Yan L, Kong M, Zhu Y, Xu Y, Guo L, Zhang L, Wang W, Yu Y, Sun J, Yang J. Stem cells as potential therapeutics for hearing loss. Front Neurosci 2023; 17:1259889. [PMID: 37746148 PMCID: PMC10512725 DOI: 10.3389/fnins.2023.1259889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023] Open
Abstract
Hearing impairment is a global health problem. Stem cell therapy has become a cutting-edge approach to tissue regeneration. In this review, the recent advances in stem cell therapy for hearing loss have been discussed. Nanomaterials can modulate the stem cell microenvironment to augment the therapeutic effects further. The potential of combining nanomaterials with stem cells for repairing and regenerating damaged inner ear hair cells (HCs) and spiral ganglion neurons (SGNs) has also been discussed. Stem cell-derived exosomes can contribute to the repair and regeneration of damaged tissue, and the research progress on exosome-based hearing loss treatment has been summarized as well. Despite stem cell therapy's technical and practical limitations, the findings reported so far are promising and warrant further investigation for eventual clinical translation.
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Affiliation(s)
- Qiaojun Fang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
- School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Yongjie Wei
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yuhua Zhang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Wei Cao
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Lin Yan
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Mengdie Kong
- School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Yongjun Zhu
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yan Xu
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Lingna Guo
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Lei Zhang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Weiqing Wang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yafeng Yu
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Jingwu Sun
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Jianming Yang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
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10
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Kong L, Domarecka E, Szczepek AJ. Histamine and Its Receptors in the Mammalian Inner Ear: A Scoping Review. Brain Sci 2023; 13:1101. [PMID: 37509031 PMCID: PMC10376984 DOI: 10.3390/brainsci13071101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Histamine is a widely distributed biogenic amine with multiple biological functions mediated by specific receptors that determine the local effects of histamine. This review aims to summarize the published findings on the expression and functional roles of histamine receptors in the inner ear and to identify potential research hotspots and gaps. METHODS A search of the electronic databases PubMed, Web of Science, and OVID EMBASE was performed using the keywords histamine, cochlea*, and inner ear. Of the 181 studies identified, 18 eligible publications were included in the full-text analysis. RESULTS All four types of histamine receptors were identified in the mammalian inner ear. The functional studies of histamine in the inner ear were mainly in vitro. Clinical evidence suggests that histamine and its receptors may play a role in Ménière's disease, but the exact mechanism is not fully understood. The effects of histamine on hearing development remain unclear. CONCLUSIONS Existing studies have successfully determined the expression of all four histamine receptors in the mammalian inner ear. However, further functional studies are needed to explore the potential of histamine receptors as targets for the treatment of hearing and balance disorders.
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Affiliation(s)
- Lingyi Kong
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Ewa Domarecka
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Agnieszka J Szczepek
- Department of Otorhinolaryngology, Head and Neck Surgery, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Faculty of Medicine and Health Sciences, University of Zielona Gora, 65-046 Zielona Gora, Poland
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11
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Bennet BM, Pardo ID, Assaf BT, Buza E, Cramer SD, Crawford LK, Engelhardt JA, Galbreath EJ, Grubor B, Morrison JP, Osborne TS, Sharma AK, Bolon B. Scientific and Regulatory Policy Committee Technical Review: Biology and Pathology of Ganglia in Animal Species Used for Nonclinical Safety Testing. Toxicol Pathol 2023; 51:278-305. [PMID: 38047294 DOI: 10.1177/01926233231213851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Dorsal root ganglia (DRG), trigeminal ganglia (TG), other sensory ganglia, and autonomic ganglia may be injured by some test article classes, including anti-neoplastic chemotherapeutics, adeno-associated virus-based gene therapies, antisense oligonucleotides, nerve growth factor inhibitors, and aminoglycoside antibiotics. This article reviews ganglion anatomy, cytology, and pathology (emphasizing sensory ganglia) among common nonclinical species used in assessing product safety for such test articles (TAs). Principal histopathologic findings associated with sensory ganglion injury include neuron degeneration, necrosis, and/or loss; increased satellite glial cell and/or Schwann cell numbers; and leukocyte infiltration and/or inflammation. Secondary nerve fiber degeneration and/or glial reactions may occur in nerves, dorsal spinal nerve roots, spinal cord (dorsal and occasionally lateral funiculi), and sometimes the brainstem. Ganglion findings related to TA administration may result from TA exposure and/or trauma related to direct TA delivery into the central nervous system or ganglia. In some cases, TA-related effects may need to be differentiated from a spectrum of artifactual and/or spontaneous background changes.
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Affiliation(s)
| | | | | | - Elizabeth Buza
- University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | | | | | | | | | - James P Morrison
- Charles River Laboratories, Inc., Shrewsbury, Massachusetts, USA
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12
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Elliott KL, Iskusnykh IY, Chizhikov VV, Fritzsch B. Ptf1a expression is necessary for correct targeting of spiral ganglion neurons within the cochlear nuclei. Neurosci Lett 2023; 806:137244. [PMID: 37055006 PMCID: PMC10210513 DOI: 10.1016/j.neulet.2023.137244] [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: 02/16/2023] [Revised: 03/09/2023] [Accepted: 04/10/2023] [Indexed: 04/15/2023]
Abstract
Two transcription factors, Atoh1 and Ptf1a, are essential for cochlear nuclei development. Atoh1 is needed to develop glutamatergic neurons, while Ptf1a is required to generate glycinergic and GABAergic neurons that migrate into the cochlear nucleus. While central projections of inner ear afferents are normal following loss of Atoh1, we wanted to know whether the loss of Ptf1a affects central projections. We found that in Ptf1a mutants, initially, afferents show a normal projection; however, a transient posterior expansion of projections to the dorsal cochlear nucleus occurs at a later stage. In addition, in older (E18.5) Ptf1a mutant mice, excessive neuronal branches form beyond the normal projection to the anterior and posterior ventral cochlear nuclei. Our results on Ptf1a null mice are comparable to that observed in loss of function Prickel1, Npr2, or Fzd3 mouse mutants. The disorganized tonotopic projections that we report in Ptf1a mutant embryos might be functionally relevant, but testing this hypothesis requires Ptf1a KO mice at postnatal stages that unfortunately cannot be performed due to their early death.
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Affiliation(s)
- Karen L Elliott
- Department of Biology, University of Iowa, Iowa, IA 52242, USA
| | - Igor Y Iskusnykh
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Victor V Chizhikov
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa, IA 52242, USA.
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13
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Wang M, Zhang C, Lin S, Xie R. Dendritic Degeneration and Altered Synaptic Innervation of a Central Auditory Neuron During Age-related Hearing Loss. Neuroscience 2023; 514:25-37. [PMID: 36738912 PMCID: PMC9992229 DOI: 10.1016/j.neuroscience.2023.01.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/08/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023]
Abstract
Cellular morphology and synaptic configuration are key determinants of neuronal function and are often modified under pathological conditions. In the first nucleus of the central auditory system, the cochlear nucleus (CN), principal bushy neurons specialize in processing temporal information of sound critical for hearing. These neurons alter their physiological properties during aging that contribute to age-related hearing loss (ARHL). The structural basis of such changes remains unclear, especially age-related modifications in their dendritic morphology and the innervating auditory nerve (AN) synapses. Using young (2-5 months) and aged (28-33 months) CBA/CaJ mice of either sex, we filled individual bushy neurons with fluorescent dye in acute brain slices to characterize their dendritic morphology, followed by immunostaining against vesicular glutamate transporter 1 (VGluT1) and calretinin (CR) to identify innervating AN synapses. We found that dendritic morphology of aged bushy neurons had significantly reduced complexity, suggesting age-dependent dendritic degeneration, especially in neurons with predominantly non-CR-expressing synapses on the soma. These dendrites were innervated by AN bouton synapses, which were predominantly non-CR-expressing in young mice but had increased proportion of CR-expressing synapses in old mice. While somatic AN synapses degenerated substantially with age, as quantified by VGluT1-labeled puncta volume, no significant difference was observed in the total volume of dendritic synapses between young and old mice. Consequently, synaptic density on dendrites was significantly higher in old mice. The findings suggest that dendritic degeneration and altered synaptic innervation in bushy neurons during aging may underlie their changed physiological activity and contribute to the development of ARHL.
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Affiliation(s)
- Meijian Wang
- Department of Otolaryngology, The Ohio State University, Columbus, OH, USA
| | - Chuangeng Zhang
- Department of Otolaryngology, The Ohio State University, Columbus, OH, USA
| | - Shengyin Lin
- Department of Otolaryngology, The Ohio State University, Columbus, OH, USA
| | - Ruili Xie
- Department of Otolaryngology, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA.
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14
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Zhang Y, Neng L, Sharma K, Hou Z, Johnson A, Song J, Dabdoub A, Shi X. Pericytes control vascular stability and auditory spiral ganglion neuron survival. eLife 2023; 12:e83486. [PMID: 36719173 PMCID: PMC9940910 DOI: 10.7554/elife.83486] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/26/2023] [Indexed: 02/01/2023] Open
Abstract
The inner ear has a rich population of pericytes, a multi-functional mural cell essential for sensory hair cell heath and normal hearing. However, the mechanics of how pericytes contribute to the homeostasis of the auditory vascular-neuronal complex in the spiral ganglion are not yet known. In this study, using an inducible and conditional pericyte depletion mouse (PDGFRB-CreERT2; ROSA26iDTR) model, we demonstrate, for the first time, that pericyte depletion causes loss of vascular volume and spiral ganglion neurons (SGNs) and adversely affects hearing sensitivity. Using an in vitro trans-well co-culture system, we show pericytes markedly promote neurite and vascular branch growth in neonatal SGN explants and adult SGNs. The pericyte-controlled neural growth is strongly mediated by pericyte-released exosomes containing vascular endothelial growth factor-A (VEGF-A). Treatment of neonatal SGN explants or adult SGNs with pericyte-derived exosomes significantly enhances angiogenesis, SGN survival, and neurite growth, all of which were inhibited by a selective blocker of VEGF receptor 2 (Flk1). Our study demonstrates that pericytes in the adult ear are critical for vascular stability and SGN health. Cross-talk between pericytes and SGNs via exosomes is essential for neuronal and vascular health and normal hearing.
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Affiliation(s)
- Yunpei Zhang
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Lingling Neng
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Kushal Sharma
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Zhiqiang Hou
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Anatasiya Johnson
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
| | - Junha Song
- Life Sciences Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Alain Dabdoub
- Biological Sciences, Sunnybrook Research InstituteTorontoCanada
- Department of Otolaryngology-Head & Neck Surgery, University of TorontoTorontoCanada
- Department of Laboratory Medicine and Pathobiology, University of TorontoTorontoCanada
| | - Xiaorui Shi
- Oregon Hearing Research Center, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science UniversityPortlandUnited States
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15
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Vohra A, Raturi P, Hussain E. Scope of using hollow fibers as a medium for drug delivery. FIBER AND TEXTILE ENGINEERING IN DRUG DELIVERY SYSTEMS 2023:169-213. [DOI: 10.1016/b978-0-323-96117-2.00013-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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16
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Levina EA, Koroleva IV, Levin SV. [Peculiarities of CI processor fitting in children with auditory neuropathy spectrum disorders]. Vestn Otorinolaringol 2023; 88:10-16. [PMID: 37184548 DOI: 10.17116/otorino20228802110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The peculiarities of cochlear implant (CI) processor fitting in children with auditory neuropathy spectrum disorders (ANSD) were investigated. At the 1-st fitting of the CI processor a standard protocol of parameters was used in all patients, including patients with cochlear nerve hypoplasia. After the initial fitting session, the behavioral tonal thresholds with CI in 55% of patients were 30-35 dB, in 32.% of patients - 40-50 dB. After 3-6 months, 65% of children with ANSD showed significant progress in auditory-speech development, which made it possible to use the standard protocol of tuning parameters for them with the most comfortable and threshold levels of electrical stimulation adjusted according to the child's reactions. The best dynamics was observed in 2 children with presynaptic ANSD with a confirmed DFNB9 (OTOF) gene mutation. In 35% of children, there was no progress in distinguishing speech signals and instability of reactions to sounds persisted after 6 months using of CI and speech therapy training, despite the low tonal thresholds of hearing. In these children the coding strategy was changed, the stimulation frequency was reduced, and the pulse width was increased. This helped to improve the discrimination of sounds with CI and progress in the child's speech development. The results demonstrate that children with ANSD require more frequent correction of CI processor settings: 1st year - every 3 months, then at least 2 times a year until the optimal coding strategy and settings are achieved. To predict the effectiveness of CI and determine the optimal tactics for setting up the CI processor in patients with ANSD, the preoperative examination should include MRI of the cerebellopontine angle to detect anomalies of the cochlear nerve and genetic examination to identify mutations that cause hearing impairment in patients with ANSD.
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Affiliation(s)
- E A Levina
- St. Petersburg Research Institute of Ear, Throat, Nose and Speech, St. Petersburg, Russia
| | - I V Koroleva
- St. Petersburg Research Institute of Ear, Throat, Nose and Speech, St. Petersburg, Russia
| | - S V Levin
- St. Petersburg Research Institute of Ear, Throat, Nose and Speech, St. Petersburg, Russia
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17
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VDR Regulates BNP Promoting Neurite Growth and Survival of Cochlear Spiral Ganglion Neurons through cGMP-PKG Signaling Pathway. Cells 2022; 11:cells11233746. [PMID: 36497006 PMCID: PMC9739822 DOI: 10.3390/cells11233746] [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: 10/09/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022] Open
Abstract
Spiral ganglion neurons (SGNs) are important for hearing, and their peripheral and central processes connect sensory cells of the Corti organ to the central nervous system. The resulting network forms a point-to-point auditory conduction. As a cardiac hormone, brain natriuretic peptide (BNP) binds to natriuretic peptide receptor type A leading to diuresis, vasodilatation, inhibition of renin and aldosterone production, and cardiac and vascular myocyte growth. This study primarily aimed to explore the expression and function of BNP in the rat's inner ear and elucidate its regulatory mechanism. We determined the expression and function of BNP and found that the vitamin D receptor (VDR) could upregulate the expression of BNP and enhance its function. In SGNs of the rat inner ear, BNP promotes neuron survival and prolongs neurite length through the cGMP-PKG signaling pathway, which could be regulated by VDR and provide a novel approach for neuronal regeneration therapy. To the best of our knowledge, this is the first study to report this potential transcriptional regulatory relationship and will act as a reference for research on neuronal regeneration therapy for SGNs injury.
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18
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Wan H, Zhang Y, Hua Q. Cellular autophagy, the compelling roles in hearing function and dysfunction. Front Cell Neurosci 2022; 16:966202. [PMID: 36246522 PMCID: PMC9561951 DOI: 10.3389/fncel.2022.966202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/14/2022] [Indexed: 11/21/2022] Open
Abstract
Sensorineural hearing loss (SNHL) is currently a major health issue. As one of the most common neurodegenerative diseases, SNHL is associated with the degradation of hair cells (HCs), spiral ganglion neurons (SGNs), the stria vascularis, supporting cells and central auditory system cells. Autophagy is a highly integrated cellular system that eliminates impaired components and replenishes energy to benefit cellular homeostasis. Etiological links between autophagy alterations and neurodegenerative diseases, such as SNHL, have been established. The hearing pathway is complex and depends on the comprehensive functions of many types of tissues and cells in auditory system. In this review, we discuss the roles of autophagy in promoting and inhibiting hearing, paying particular attention to specific cells in the auditory system, as discerned through research. Hence, our review provides enlightening ideas for the role of autophagy in hearing development and impairment.
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Affiliation(s)
- Huanzhi Wan
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
- Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yuanyuan Zhang
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
- Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
- *Correspondence: Yuanyuan Zhang,
| | - Qingquan Hua
- Department of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
- Research Institute of Otolaryngology-Head and Neck Surgery, Renmin Hospital of Wuhan University, Wuhan, China
- Qingquan Hua,
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19
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Shehabi AM, Prendergast G, Plack CJ. The Relative and Combined Effects of Noise Exposure and Aging on Auditory Peripheral Neural Deafferentation: A Narrative Review. Front Aging Neurosci 2022; 14:877588. [PMID: 35813954 PMCID: PMC9260498 DOI: 10.3389/fnagi.2022.877588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/30/2022] [Indexed: 11/13/2022] Open
Abstract
Animal studies have shown that noise exposure and aging cause a reduction in the number of synapses between low and medium spontaneous rate auditory nerve fibers and inner hair cells before outer hair cell deterioration. This noise-induced and age-related cochlear synaptopathy (CS) is hypothesized to compromise speech recognition at moderate-to-high suprathreshold levels in humans. This paper evaluates the evidence on the relative and combined effects of noise exposure and aging on CS, in both animals and humans, using histopathological and proxy measures. In animal studies, noise exposure seems to result in a higher proportion of CS (up to 70% synapse loss) compared to aging (up to 48% synapse loss). Following noise exposure, older animals, depending on their species, seem to either exhibit significant or little further synapse loss compared to their younger counterparts. In humans, temporal bone studies suggest a possible age- and noise-related auditory nerve fiber loss. Based on the animal data obtained from different species, we predict that noise exposure may accelerate age-related CS to at least some extent in humans. In animals, noise-induced and age-related CS in separation have been consistently associated with a decreased amplitude of wave 1 of the auditory brainstem response, reduced middle ear muscle reflex strength, and degraded temporal processing as demonstrated by lower amplitudes of the envelope following response. In humans, the individual effects of noise exposure and aging do not seem to translate clearly into deficits in electrophysiological, middle ear muscle reflex, and behavioral measures of CS. Moreover, the evidence on the combined effects of noise exposure and aging on peripheral neural deafferentation in humans using electrophysiological and behavioral measures is even more sparse and inconclusive. Further research is necessary to establish the individual and combined effects of CS in humans using temporal bone, objective, and behavioral measures.
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Affiliation(s)
- Adnan M. Shehabi
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Audiology and Speech Therapy, Birzeit University, Birzeit, Palestine
| | - Garreth Prendergast
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
| | - Christopher J. Plack
- Manchester Centre for Audiology and Deafness, University of Manchester, Manchester, United Kingdom
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
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20
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Suthakar K, Liberman MC. Noise Masking in Cochlear Synaptopathy: Auditory Brainstem Response vs. Auditory Nerve Response in Mouse. J Neurophysiol 2022; 127:1574-1585. [PMID: 35583974 PMCID: PMC9169830 DOI: 10.1152/jn.00402.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 04/28/2022] [Accepted: 05/12/2022] [Indexed: 11/22/2022] Open
Abstract
After acoustic overexposure, many auditory-nerve fiber (ANF) synapses permanently retract from surviving cochlear hair cells. This synaptopathy is hard to diagnose, since it does not elevate audiometric thresholds until almost no synapses remain, nevertheless it may degrade discrimination of complex stimuli especially in noisy environments. Here, we study an assay based on masking the auditory brainstem responses (ABRs) to a moderate-level probe tone with continuous noise of varied sound levels, and we investigate the underlying ANF responses at the single-fiber level. Synaptopathy was induced by overexposure to octave-band noise, resulting in a permanent synaptic loss of ~50%, without permanent threshold elevation except at the highest frequencies. The normal progressive delay of ABR peaks with increasing masker level is diminished in synaptopathic ears; however, the single-fiber analysis suggests that this normal latency shift does not arise because contributing ANFs shift from low-threshold fibers (with high spontaneous rates) to high-threshold fibers (with low spontaneous rates). Rather, it may arise because of a shift in the cochlear region dominating the response. Surprisingly, the dynamic range of masking, i.e. the difference between the lowest masker level that attenuates the ABR to a fixed-level probe and the lowest masker level that eliminates the ABR, is enhanced in the synaptopathic ears. This ABR behavior mirrors the single-fiber data showing a paradoxical enhancement of onset-response synchrony and resistance to masking in responses of ANFs in the synaptopathic regions. An assay based on the dynamic range of masking could be useful in diagnosing synaptic damage in human populations.
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Affiliation(s)
- Kirupa Suthakar
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
| | - M Charles Liberman
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
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21
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Schwieger J, Frisch AS, Rau TS, Lenarz T, Hügl S, Scheper V. 3D Printed Cell Culture Chamber for Testing the Effect of Pump-Based Chronic Drug Delivery on Inner Ear Tissue. Biomolecules 2022; 12:biom12040589. [PMID: 35454178 PMCID: PMC9032916 DOI: 10.3390/biom12040589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/11/2022] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Cochlear hair cell damage and spiral ganglion neuron (SGN) degeneration are the main causes of sensory neural hearing loss. Cochlear implants (CIs) can replace the function of the hair cells and stimulate the SGNs electrically. The condition of the SGNs and their spatial distance to the CI are key factors for CI-functionality. For a better performance, a high number of neurons and a closer contact to the electrode are intended. Neurotrophic factors are able to enhance SGN survival and neurite outgrowth, and thereby might optimize the electrode-nerve interaction. This would require chronic factor treatment, which is not yet established for the inner ear. Investigations on chronic drug delivery to SGNs could benefit from an appropriate in vitro model. Thus, an inner ear inspired Neurite Outgrowth Chamber (NOC), which allows the incorporation of a mini-osmotic pump for long-term drug delivery, was designed and three-dimensionally printed. The NOC’s function was validated using spiral ganglion explants treated with ciliary neurotrophic factor, neurotrophin-3, or control fluid released via pumps over two weeks. The NOC proved to be suitable for explant cultivation and observation of pump-based drug delivery over the examined period, with neurotrophin-3 significantly increasing neurite outgrowth compared to the other groups.
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Affiliation(s)
- Jana Schwieger
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
- Correspondence: ; Tel.: +49-5115327262
| | - Anna Sophie Frisch
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
| | - Thomas S. Rau
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Thomas Lenarz
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Silke Hügl
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
| | - Verena Scheper
- Department of Otorhinolaryngology, Head and Neck Surgery, Hannover Medical School, 30625 Hannover, Germany; (A.S.F.); (T.S.R.); (T.L.); (S.H.); (V.S.)
- Lower Saxony Center for Biomedical Engineering, Implant Research and Development (NIFE), Stadtfelddamm 34, 30625 Hannover, Germany
- Cluster of Excellence “Hearing4all” EXC 1077/2, 30625 Hannover, Germany
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22
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Zhang C, Wang M, Lin S, Xie R. Calretinin-Expressing Synapses Show Improved Synaptic Efficacy with Reduced Asynchronous Release during High-Rate Activity. J Neurosci 2022; 42:2729-2742. [PMID: 35165172 PMCID: PMC8973423 DOI: 10.1523/jneurosci.1773-21.2022] [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: 08/31/2021] [Revised: 01/27/2022] [Accepted: 02/07/2022] [Indexed: 11/21/2022] Open
Abstract
Calretinin (CR) is a major calcium binding protein widely expressed in the CNS. However, its synaptic function remains largely elusive. At the auditory synapse of the endbulb of Held, CR is selectively expressed in different subtypes. Combining electrophysiology with immunohistochemistry, we investigated the synaptic transmission at the endbulb of Held synapses with and without endogenous CR expression in mature CBA/CAJ mice of either sex. Two synapse subtypes showed similar basal synaptic transmission, except a larger quantal size in CR-expressing synapses. During high-rate stimulus trains, CR-expressing synapses showed improved synaptic efficacy with significantly less depression and lower asynchronous release, suggesting more efficient exocytosis than non-CR-expressing synapses. Conversely, CR-expressing synapses had a smaller readily releasable pool size, which was countered by higher release probability and faster synaptic recovery to support sustained release during high-rate activity. EGTA-AM treatment did not change the synaptic transmission of CR-expressing synapses, but reduced synaptic depression and decreased asynchronous release at non-CR-expressing synapses, suggesting that CR helps to minimize calcium accumulation during high-rate activity. Both synapses express parvalbumin, another calcium-binding protein with slower kinetics and higher affinity than CR, but not calbindin. Furthermore, CR-expressing synapses only express the fast isoform of vesicular glutamate transporter 1 (VGluT1), while most non-CR-expressing synapses express both VGluT1 and the slower VGluT2, which may underlie their lagged synaptic recovery. The findings suggest that, paired with associated synaptic machinery, differential CR expression regulates synaptic efficacy among different subtypes of auditory nerve synapses to accomplish distinctive physiological functions in transmitting auditory information at high rates.SIGNIFICANCE STATEMENT CR is a major calcium-binding protein in the brain. It remains unclear how endogenous CR impacts synaptic transmission. We investigated the question at the large endbulb of Held synapses with selective CR expression and found that CR-expressing and non-CR-expressing synapses had similar release properties under basal synaptic transmission. During high-rate activity, however, CR-expressing synapses showed improved synaptic efficacy with less depression, lower asynchronous release, and faster recovery. Furthermore, CR-expressing synapses use exclusive VGluT1 to refill synaptic vesicles, while non-CR-expressing synapses use both VGluT1 and the slower isoform of VGluT2. Our findings suggest that CR may play significant roles in promoting synaptic efficacy during high-rate activity, and selective CR expression can differentially impact signal processing among different synapses.
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Affiliation(s)
- Chuangeng Zhang
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio 43210
| | - Meijian Wang
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio 43210
| | - Shengyin Lin
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio 43210
| | - Ruili Xie
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, Ohio 43210
- Department of Neuroscience, The Ohio State University, Columbus, Ohio 43210
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23
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An X, Wang Y, Han B, Hong L, Zha D, Han Y. Expression and distribution of Nob1 in the developing rat cochleae. Gene Expr Patterns 2022; 44:119235. [DOI: 10.1016/j.gep.2022.119235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/21/2022] [Accepted: 03/04/2022] [Indexed: 11/04/2022]
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24
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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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25
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Hu Z, Komal F, Singh A, Deng M. Generation of a Spiral Ganglion Neuron Degeneration Mouse Model. Front Cell Dev Biol 2021; 9:761847. [PMID: 34778272 PMCID: PMC8578993 DOI: 10.3389/fcell.2021.761847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 09/29/2021] [Indexed: 11/27/2022] Open
Abstract
Spiral ganglion neurons (SGNs) can be injured by a wide variety of insults. However, there still is a lack of degeneration models to specifically damage the SGNs without disturbing other types of cells in the inner ear. This study aims to generate an SGN-specific damage model using the Cre-LoxP transgenic mouse strains. The Cre-inducible diphtheria toxin receptor (iDTR+/+) knock-in mouse strain was crossed with a mouse strain with Cre activity specific to neurons (NeflCreER/CreER). Expression of the Cre-recombinase activity was evaluated using the reporter mouse strain Ai9 at pre-hearing, hearing onset, and post-hearing stages. Accordingly, heterozygous NeflCreER/+;iDTR+/– mice were treated with tamoxifen on postnatal days 1–5 (P1–5), followed by diphtheria toxin (DT) or vehicle injection on P7, P14, and P21 to evaluate the SGN loss. Robust tamoxifen-induced Cre-mediated Ai9 tdTomato fluorescence was observed in the SGN area of heterozygous NeflCreER/+;Ai9+/– mice treated with tamoxifen, whereas vehicle-treated heterozygote mice did not show tdTomato fluorescence. Compared to vehicle-treated NeflCreER/+;iDTR+/– mice, DT-treated NeflCreER/+;iDTR+/– mice showed significant auditory brainstem response (ABR) threshold shifts and SGN cell loss. Hair cell count and functional study did not show significant changes. These results demonstrate that the NeflCreER/CreER mouse strain exhibits inducible SGN-specific Cre activity in the inner ear, which may serve as a valuable SGN damage model for regeneration research of the inner ear.
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Affiliation(s)
- Zhengqing Hu
- John D. Dingell VA Medical Center, Detroit, MI, United States.,Department of Otolaryngology-HNS, Wayne State University School of Medicine, Detroit, MI, United States
| | - Fnu Komal
- Department of Otolaryngology-HNS, Wayne State University School of Medicine, Detroit, MI, United States
| | - Aditi Singh
- Department of Otolaryngology-HNS, Wayne State University School of Medicine, Detroit, MI, United States
| | - Meng Deng
- Department of Otolaryngology-HNS, Wayne State University School of Medicine, Detroit, MI, United States
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26
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He Z, Ding Y, Mu Y, Xu X, Kong W, Chai R, Chen X. Stem Cell-Based Therapies in Hearing Loss. Front Cell Dev Biol 2021; 9:730042. [PMID: 34746126 PMCID: PMC8567027 DOI: 10.3389/fcell.2021.730042] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/04/2021] [Indexed: 12/19/2022] Open
Abstract
In recent years, neural stem cell transplantation has received widespread attention as a new treatment method for supplementing specific cells damaged by disease, such as neurodegenerative diseases. A number of studies have proved that the transplantation of neural stem cells in multiple organs has an important therapeutic effect on activation and regeneration of cells, and restore damaged neurons. This article describes the methods for inducing the differentiation of endogenous and exogenous stem cells, the implantation operation and regulation of exogenous stem cells after implanted into the inner ear, and it elaborates the relevant signal pathways of stem cells in the inner ear, as well as the clinical application of various new materials. At present, stem cell therapy still has limitations, but the role of this technology in the treatment of hearing diseases has been widely recognized. With the development of related research, stem cell therapy will play a greater role in the treatment of diseases related to the inner ear.
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Affiliation(s)
- Zuhong He
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yanyan Ding
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yurong Mu
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoxiang Xu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, School of Life Sciences and Technology, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Xiong Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
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27
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Kalluri R. Similarities in the Biophysical Properties of Spiral-Ganglion and Vestibular-Ganglion Neurons in Neonatal Rats. Front Neurosci 2021; 15:710275. [PMID: 34712112 PMCID: PMC8546178 DOI: 10.3389/fnins.2021.710275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
The membranes of auditory and vestibular afferent neurons each contain diverse groups of ion channels that lead to heterogeneity in their intrinsic biophysical properties. Pioneering work in both auditory- and vestibular-ganglion physiology have individually examined this remarkable diversity, but there are few direct comparisons between the two ganglia. Here the firing patterns recorded by whole-cell patch-clamping in neonatal vestibular- and spiral ganglion neurons are compared. Indicative of an overall heterogeneity in ion channel composition, both ganglia exhibit qualitatively similar firing patterns ranging from sustained-spiking to transient-spiking in response to current injection. The range of resting potentials, voltage thresholds, current thresholds, input-resistances, and first-spike latencies are similarly broad in both ganglion groups. The covariance between several biophysical properties (e.g., resting potential to voltage threshold and their dependence on postnatal age) was similar between the two ganglia. Cell sizes were on average larger and more variable in VGN than in SGN. One sub-group of VGN stood out as having extra-large somata with transient-firing patterns, very low-input resistance, fast first-spike latencies, and required large current amplitudes to induce spiking. Despite these differences, the input resistance per unit area of the large-bodied transient neurons was like that of smaller-bodied transient-firing neurons in both VGN and SGN, thus appearing to be size-scaled versions of other transient-firing neurons. Our analysis reveals that although auditory and vestibular afferents serve very different functions in distinct sensory modalities, their biophysical properties are more closely related by firing pattern and cell size than by sensory modality.
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Affiliation(s)
- Radha Kalluri
- Caruso Department of Otolaryngology-Head and Neck Surgery, Zilkha Neurogenetics Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States
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28
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Parra-Munevar J, Morse CE, Plummer MR, Davis RL. Dynamic Heterogeneity Shapes Patterns of Spiral Ganglion Activity. J Neurosci 2021; 41:8859-8875. [PMID: 34551939 PMCID: PMC8549539 DOI: 10.1523/jneurosci.0924-20.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/17/2021] [Accepted: 09/08/2021] [Indexed: 11/21/2022] Open
Abstract
Neural response properties that typify primary sensory afferents are critical to fully appreciate because they establish and, ultimately represent, the fundamental coding design used for higher-level processing. Studies illuminating the center-surround receptive fields of retinal ganglion cells, for example, were ground-breaking because they determined the foundation of visual form detection. For the auditory system, a basic organizing principle of the spiral ganglion afferents is their extensive electrophysiological heterogeneity establishing diverse intrinsic firing properties in neurons throughout the spiral ganglion. Moreover, these neurons display an impressively large array of neurotransmitter receptor types that are responsive to efferent feedback. Thus, electrophysiological diversity and its neuromodulation are a fundamental encoding mechanism contributed by the primary afferents in the auditory system. To place these features into context, we evaluated the effects of hyperpolarization and cAMP on threshold level as indicators of overall afferent responsiveness in CBA/CaJ mice of either sex. Hyperpolarization modified threshold gradients such that distinct voltage protocols could shift the relationship between sensitivity and stimulus input to reshape resolution. This resulted in an "accordion effect" that appeared to stretch, compress, or maintain responsivity across the gradient of afferent thresholds. cAMP targeted threshold and kinetic shifts to rapidly adapting neurons, thus revealing multiple cochleotopic properties that could potentially be independently regulated. These examples of dynamic heterogeneity in primary auditory afferents not only have the capacity to shift the range, sensitivity, and resolution, but to do so in a coordinated manner that appears to orchestrate changes with a seemingly unlimited repertoire.SIGNIFICANCE STATEMENT How do we discriminate the more nuanced qualities of the sound around us? Beyond the basics of pitch and loudness, aspects, such as pattern, distance, velocity, and location, are all attributes that must be used to encode acoustic sensations effectively. While higher-level processing is required for perception, it would not be unexpected if the primary auditory afferents optimized receptor input to expedite neural encoding. The findings reported herein are consistent with this design. Neuromodulation compressed, expanded, shifted, or realigned intrinsic electrophysiological heterogeneity to alter neuronal responses selectively and dynamically. This suggests that diverse spiral ganglion phenotypes provide a rich substrate to support an almost limitless array of coding strategies within the first neural element of the auditory pathway.
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Affiliation(s)
- Jeffrey Parra-Munevar
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
| | - Charles E Morse
- Department of Neurosurgery, Jefferson Hospital for Neuroscience, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107
| | - Mark R Plummer
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
| | - Robin L Davis
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
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29
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Sun F, Zhou K, Tian KY, Zhang XY, Liu W, Wang J, Zhong CP, Qiu JH, Zha DJ. Atrial Natriuretic Peptide Promotes Neurite Outgrowth and Survival of Cochlear Spiral Ganglion Neurons in vitro Through NPR-A/cGMP/PKG Signaling. Front Cell Dev Biol 2021; 9:681421. [PMID: 34268307 PMCID: PMC8276373 DOI: 10.3389/fcell.2021.681421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/10/2021] [Indexed: 01/22/2023] Open
Abstract
Sensorineural hearing loss (SNHL) is a dominant public health issue affecting millions of people around the globe, which is correlated with the irreversible deterioration of the hair cells and spiral ganglion neurons (SGNs) within the cochlea. Strategies using bioactive molecules that regulate neurite regeneration and neuronal survival to reestablish connections between auditory epithelium or implanted electrodes and SGN neurites would become attractive therapeutic candidates for SNHL. As an intracellular second messenger, cyclic guanosine-3’,5’-monophosphate (cGMP) can be synthesized through activation of particulate guanylate cyclase-coupled natriuretic peptide receptors (NPRs) by natriuretic peptides, which in turn modulates multiple aspects of neuronal functions including neuronal development and neuronal survival. As a cardiac-derived hormone, atrial natriuretic peptide (ANP), and its specific receptors (NPR-A and NPR-C) are broadly expressed in the nervous system where they might be involved in the maintenance of diverse neural functions. Despite former literatures and our reports indicating the existence of ANP and its receptors within the inner ear, particularly in the spiral ganglion, their potential regulatory mechanisms underlying functional properties of auditory neurons are still incompletely understood. Our recently published investigation revealed that ANP could promote the neurite outgrowth of SGNs by activating NPR-A/cGMP/PKG cascade in a dose-dependent manner. In the present research, the influence of ANP and its receptor-mediated downstream signaling pathways on neurite outgrowth, neurite attraction, and neuronal survival of SGNs in vitro was evaluated by employing cultures of organotypic explant and dissociated neuron from postnatal rats. Our data indicated that ANP could support and attract neurite outgrowth of SGNs and possess a high capacity to improve neuronal survival of SGNs against glutamate-induced excitotoxicity by triggering the NPR-A/cGMP/PKG pathway. The neuroregenerative and neuroprotective effects of ANP/NPRA/cGMP/PKG-dependent signaling on SGNs would represent an attractive therapeutic candidate for hearing impairment.
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Affiliation(s)
- Fei Sun
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ke Zhou
- Department of Laboratory Medicine, Institute of Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ke-Yong Tian
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xin-Yu Zhang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wei Liu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jie Wang
- Department of Otolaryngology-Head and Neck Surgery, The Affiliated Children Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Cui-Ping Zhong
- Department of Otolaryngology-Head and Neck Surgery, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, China
| | - Jian-Hua Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ding-Jun Zha
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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30
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Maharajan N, Cho GW, Jang CH. Therapeutic Application of Mesenchymal Stem Cells for Cochlear Regeneration. In Vivo 2021; 35:13-22. [PMID: 33402445 DOI: 10.21873/invivo.12227] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 09/27/2020] [Accepted: 09/30/2020] [Indexed: 12/11/2022]
Abstract
Hearing loss is one of the major worldwide health problems that seriously affects human social and cognitive development. In the auditory system, three components outer ear, middle ear and inner ear are essential for the hearing mechanism. In the inner ear, sensory hair cells and ganglion neuronal cells are the essential supporters for hearing mechanism. Damage to these cells can be caused by long-term exposure of excessive noise, ototoxic drugs (aminoglycosides), ear tumors, infections, heredity and aging. Since mammalian cochlear hair cells do not regenerate naturally, some therapeutic interventions may be required to replace the damaged or lost cells. Cochlear implants and hearing aids are the temporary solutions for people suffering from severe hearing loss. The current discoveries in gene therapy may provide a deeper understanding in essential genes for the inner ear regeneration. Stem cell migration, survival and differentiation to supporting cells, cochlear hair cells and spiral ganglion neurons are the important foundation in understanding stem cell therapy. Moreover, mesenchymal stem cells (MSCs) from different sources (bone marrow, umbilical cord, adipose tissue and placenta) could be used in inner ear therapy. Transplanted MSCs in the inner ear can recruit homing factors at the damaged sites to induce transdifferentiation into inner hair cells and ganglion neurons or regeneration of sensory hair cells, thus enhancing the cochlear function. This review summarizes the potential application of mesenchymal stem cells in hearing restoration and combining stem cell and molecular therapeutic strategies can also be used in the recovery of cochlear function.
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Affiliation(s)
- Nagarajan Maharajan
- Department of Biology, College of Natural Science, BK21-Plus Research Team for Bioactive Control Technology, Chosun University, Gwangju, Republic of Korea
| | - Gwang Won Cho
- Department of Biology, College of Natural Science, BK21-Plus Research Team for Bioactive Control Technology, Chosun University, Gwangju, Republic of Korea
| | - Chul Ho Jang
- Department of Otolaryngology, Chonnam National University Medical School, Gwangju, Republic of Korea
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31
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Elliott KL, Kersigo J, Lee JH, Jahan I, Pavlinkova G, Fritzsch B, Yamoah EN. Developmental Changes in Peripherin-eGFP Expression in Spiral Ganglion Neurons. Front Cell Neurosci 2021; 15:678113. [PMID: 34211371 PMCID: PMC8239239 DOI: 10.3389/fncel.2021.678113] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
The two types of spiral ganglion neurons (SGNs), types I and II, innervate inner hair cells and outer hair cells, respectively, within the mammalian cochlea and send another process back to cochlear nuclei in the hindbrain. Studying these two neuronal types has been made easier with the identification of unique molecular markers. One of these markers, peripherin, was shown using antibodies to be present in all SGNs initially but becomes specific to type II SGNs during maturation. We used mice with fluorescently labeled peripherin (Prph-eGFP) to examine peripherin expression in SGNs during development and in aged mice. Using these mice, we confirm the initial expression of Prph-eGFP in both types I and II neurons and eventual restriction to only type II perikarya shortly after birth. However, while Prph-eGFP is uniquely expressed within type II cell bodies by P8, both types I and II peripheral and central processes continue to express Prph-eGFP for some time before becoming downregulated. Only at P30 was there selective type II Prph-eGFP expression in central but not peripheral processes. By 9 months, only the type II cell bodies and more distal central processes retain Prph-eGFP expression. Our results show that Prph-eGFP is a reliable marker for type II SGN cell bodies beyond P8; however, it is not generally a suitable marker for type II processes, except for central processes beyond P30. How the changes in Prph-eGFP expression relate to subsequent protein expression remains to be explored.
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Affiliation(s)
- Karen L Elliott
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | - Jennifer Kersigo
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | - Jeong Han Lee
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV, United States
| | - Israt Jahan
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | | | - Bernd Fritzsch
- Department of Biology, CLAS, The University of Iowa, Iowa City, IA, United States.,Department of Otolaryngology, CLAS, The University of Iowa, Iowa City, IA, United States
| | - Ebenezer N Yamoah
- Department of Physiology, School of Medicine, University of Nevada, Reno, Reno, NV, United States
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32
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Yang S, Ma N, Wu X, Ni H, Gao S, Sun L, Zhou P, Tala, Ran J, Zhou J, Liu M, Li D. CYLD deficiency causes auditory neuropathy due to reduced neurite outgrowth. J Clin Lab Anal 2021; 35:e23783. [PMID: 33934395 PMCID: PMC8183908 DOI: 10.1002/jcla.23783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 03/19/2021] [Accepted: 03/28/2021] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Auditory neuropathy is a cause of hearing loss that has been studied in a number of animal models. Signal transmission from hair cells to spiral ganglion neurons plays an important role in normal hearing. CYLD is a microtubule-binding protein, and deubiquitinase involved in the regulation of various cellular processes. In this study, we used Cyld knockout (KO) mice and nerve cell lines to examine whether CYLD is associated with auditory neuropathy. METHODS Hearing of Cyld KO mice was studied using the TDT RZ6 auditory physiology workstation. The expression and localization of CYLD in mouse cochlea and cell lines were examined by RT-PCR, immunoblotting, and immunofluorescence. CYLD expression was knocked down in SH-SY5Y cells by shRNAs and in PC12 and N2A cells by siRNAs. Nerve growth factor and retinoic acid were used to induce neurite outgrowth, and the occurrence and length of neurites were statistically analyzed between knockdown and control groups. RESULTS Cyld KO mice had mild hearing impairment. Moreover, CYLD was widely expressed in mouse cochlear tissues and different nerve cell lines. Knocking down CYLD significantly reduced the length and proportion of neurites growing from nerve cells. CONCLUSIONS The abnormal hearing of Cyld KO mice might be caused by a decrease in the length and number of neurites growing from auditory nerve cells in the cochlea, suggesting that CYLD is a key protein affecting hearing.
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Affiliation(s)
- Song Yang
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Nan Ma
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Xuemei Wu
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Hua Ni
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Siqi Gao
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Lei Sun
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Peng Zhou
- Shandong Provincial Key Laboratory of Animal Resistance BiologyCollaborative Innovation Center of Cell Biology in Universities of ShandongInstitute of Biomedical SciencesCollege of Life SciencesShandong Normal UniversityJinanChina
| | - Tala
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
| | - Jie Ran
- Shandong Provincial Key Laboratory of Animal Resistance BiologyCollaborative Innovation Center of Cell Biology in Universities of ShandongInstitute of Biomedical SciencesCollege of Life SciencesShandong Normal UniversityJinanChina
| | - Jun Zhou
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
- Shandong Provincial Key Laboratory of Animal Resistance BiologyCollaborative Innovation Center of Cell Biology in Universities of ShandongInstitute of Biomedical SciencesCollege of Life SciencesShandong Normal UniversityJinanChina
| | - Min Liu
- Shandong Provincial Key Laboratory of Animal Resistance BiologyCollaborative Innovation Center of Cell Biology in Universities of ShandongInstitute of Biomedical SciencesCollege of Life SciencesShandong Normal UniversityJinanChina
| | - Dengwen Li
- State Key Laboratory of Medicinal Chemical BiologyCollege of Life SciencesNankai UniversityTianjinChina
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33
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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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34
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Liu W, Xu L, Wang X, Zhang D, Sun G, Wang M, Wang M, Han Y, Chai R, Wang H. PRDX1 activates autophagy via the PTEN-AKT signaling pathway to protect against cisplatin-induced spiral ganglion neuron damage. Autophagy 2021; 17:4159-4181. [PMID: 33749526 PMCID: PMC8726717 DOI: 10.1080/15548627.2021.1905466] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Spiral ganglion neurons (SGNs) are auditory neurons that relay sound signals from the inner ear to the brainstem. The ototoxic drug cisplatin can damage SGNs and thus lead to sensorineural hearing loss (SNHL), and there are currently no methods for preventing or treating this. Macroautophagy/autophagy plays a critical role in SGN development, but the effect of autophagy on cisplatin-induced SGN injury is unclear. Here, we first found that autophagic flux was activated in SGNs after cisplatin damage. The SGN apoptosis and related hearing loss induced by cisplatin were alleviated after co-treatment with the autophagy activator rapamycin, whereas these were exacerbated by the autophagy inhibitor 3-methyladenine, indicating that instead of inducing SGN death, autophagy played a neuroprotective role in SGNs treated with cisplatin both in vitro and in vivo. We further demonstrated that autophagy attenuated reactive oxygen species (ROS) accumulation and alleviated cisplatin-induced oxidative stress in SGNs to mediate its protective effects. Notably, the role of the antioxidant enzyme PRDX1 (peroxiredoxin 1) in modulating autophagy in SGNs was first identified. Deficiency in PRDX1 suppressed autophagy and increased SGN loss after cisplatin exposure, while upregulating PRDX1 pharmacologically or by adeno-associated virus activated autophagy and thus inhibited ROS accumulation and apoptosis and attenuated SGN loss induced by cisplatin. Finally, we showed that the underlying mechanism through which PRDX1 triggers autophagy in SGNs was, at least partially, through activation of the PTEN-AKT signaling pathway. These findings suggest potential therapeutic targets for the amelioration of drug-induced SNHL through autophagy activation. Abbreviations: 3-MA: 3-methyladenine; AAV : adeno-associated virus; ABR: auditory brainstem responses; AKT/protein kinase B: thymoma viral proto-oncogene; Baf: bafilomycin A1; CAP: compound action potential; COX4I1: cytochrome c oxidase subunit 4I1; Cys: cysteine; ER: endoplasmic reticulum; H2O2: hydrogen peroxide; HC: hair cell; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; NAC: N-acetylcysteine; PRDX1: peroxiredoxin 1; PTEN: phosphatase and tensin homolog; RAP: rapamycin; ROS: reactive oxygen species; SGNs: spiral ganglion neurons; SNHL: sensorineural hearing loss; SQSTM1/p62: sequestosome 1; TOMM20: translocase of outer mitochondrial membrane 20; TUNEL: terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling; WT: wild type.
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Affiliation(s)
- Wenwen Liu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Lei Xu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xue Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Daogong Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Gaoying Sun
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Man Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Mingming Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yuechen Han
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Renjie Chai
- State Key Laboratory of Bioelectronics, School of Life Sciences and Technology, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Haibo Wang
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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Establishing Reproducibility and Correlation of Cochlear Microphonic Amplitude to Implant Electrode Position Using Intraoperative Electrocochleography and Postoperative Cone Beam Computed Tomography. Ear Hear 2021; 42:1263-1275. [PMID: 33813521 PMCID: PMC8378545 DOI: 10.1097/aud.0000000000001010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Supplemental Digital Content is available in the text. Objectives: The primary objective of this study was to establish the reproducibility of cochlear microphonic (CM) recordings obtained from a cochlear implant (CI) electrode contact during and immediately after insertion. This was achieved by evaluating the insertion angle and calculating the position of the apical electrode contact during insertion, using postoperative cone beam computed tomography (CBCT). The secondary objective was to create individualized patient maps of electrode contacts located within acoustically sensitive regions by correlating the CM amplitude to the electrode position determined using CBCT. Methods: CMs were recorded from a CI electrode contact during and immediately after insertion in 12 patients (n = 14 ears). Intraoperative recordings were made for a 0.5 kHz tone burst stimulus and were recorded from the apical electrode contact. Postinsertion recordings were made from the odd-numbered electrode contacts (1–15) along the array, using a range of stimulus frequencies (from 0.125 to 2 kHz). The time point at which each electrode contact passed through the round window was noted throughout the insertion, and the CM amplitude at this point was correlated to postoperative CBCT. This correlation was then used to estimate the CM amplitude at particular points within the cochlea, which was in turn compared with the amplitudes recorded from each electrode postoperatively to assess the reproducibility of the recordings. Results: Significant correlation was shown between intraoperative insertion and postinsertion angles at two amplitude events (maximum amplitude: 29° mean absolute error, r = 0.77, p = 0.006; 10% of maximum amplitude: 52° mean absolute error, r = 0.85, p = 0.002). Conclusion: We have developed a novel method to demonstrate the reproducibility of the CM responses recorded from a CI electrode during insertion. By correlating the CM amplitude with the postoperative CBCT, we have also been able to create individualized maps of CM responses, categorizing the cochlea into acoustically responsive and unresponsive regions. If the electrode contacts within the acoustically sensitive regions are shown to be associated with improved loudness discrimination, it could have implications for optimal electrode mapping and placement.
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Röth K, Shao S, Gjorgjieva J. Efficient population coding depends on stimulus convergence and source of noise. PLoS Comput Biol 2021; 17:e1008897. [PMID: 33901195 PMCID: PMC8075262 DOI: 10.1371/journal.pcbi.1008897] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 03/19/2021] [Indexed: 11/30/2022] Open
Abstract
Sensory organs transmit information to downstream brain circuits using a neural code comprised of spikes from multiple neurons. According to the prominent efficient coding framework, the properties of sensory populations have evolved to encode maximum information about stimuli given biophysical constraints. How information coding depends on the way sensory signals from multiple channels converge downstream is still unknown, especially in the presence of noise which corrupts the signal at different points along the pathway. Here, we calculated the optimal information transfer of a population of nonlinear neurons under two scenarios. First, a lumped-coding channel where the information from different inputs converges to a single channel, thus reducing the number of neurons. Second, an independent-coding channel when different inputs contribute independent information without convergence. In each case, we investigated information loss when the sensory signal was corrupted by two sources of noise. We determined critical noise levels at which the optimal number of distinct thresholds of individual neurons in the population changes. Comparing our system to classical physical systems, these changes correspond to first- or second-order phase transitions for the lumped- or the independent-coding channel, respectively. We relate our theoretical predictions to coding in a population of auditory nerve fibers recorded experimentally, and find signatures of efficient coding. Our results yield important insights into the diverse coding strategies used by neural populations to optimally integrate sensory stimuli in the presence of distinct sources of noise.
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Affiliation(s)
- Kai Röth
- Computation in Neural Circuits Group, Max Planck Institute for Brain Research, Frankfurt, Germany
- School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Shuai Shao
- Computation in Neural Circuits Group, Max Planck Institute for Brain Research, Frankfurt, Germany
- Donders Institute and Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Julijana Gjorgjieva
- Computation in Neural Circuits Group, Max Planck Institute for Brain Research, Frankfurt, Germany
- School of Life Sciences, Technical University of Munich, Freising, Germany
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Stojkovic M, Han D, Jeong M, Stojkovic P, Stankovic KM. Human induced pluripotent stem cells and CRISPR/Cas-mediated targeted genome editing: Platforms to tackle sensorineural hearing loss. STEM CELLS (DAYTON, OHIO) 2021; 39:673-696. [PMID: 33586253 DOI: 10.1002/stem.3353] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 12/13/2020] [Indexed: 11/09/2022]
Abstract
Hearing loss (HL) is a major global health problem of pandemic proportions. The most common type of HL is sensorineural hearing loss (SNHL) which typically occurs when cells within the inner ear are damaged. Human induced pluripotent stem cells (hiPSCs) can be generated from any individual including those who suffer from different types of HL. The development of new differentiation protocols to obtain cells of the inner ear including hair cells (HCs) and spiral ganglion neurons (SGNs) promises to expedite cell-based therapy and screening of potential pharmacologic and genetic therapies using human models. Considering age-related, acoustic, ototoxic, and genetic insults which are the most frequent causes of irreversible damage of HCs and SGNs, new methods of genome editing (GE), especially the CRISPR/Cas9 technology, could bring additional opportunities to understand the pathogenesis of human SNHL and identify novel therapies. However, important challenges associated with both hiPSCs and GE need to be overcome before scientific discoveries are correctly translated to effective and patient-safe applications. The purpose of the present review is (a) to summarize the findings from published reports utilizing hiPSCs for studies of SNHL, hence complementing recent reviews focused on animal studies, and (b) to outline promising future directions for deciphering SNHL using disruptive molecular and genomic technologies.
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Affiliation(s)
- Miodrag Stojkovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Dongjun Han
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Minjin Jeong
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Petra Stojkovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Konstantina M Stankovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA.,Program in Speech and Hearing Bioscience and Technology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Program in Therapeutic Science, Harvard Medical School, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
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38
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Wang M, Zhang C, Lin S, Wang Y, Seicol BJ, Ariss RW, Xie R. Biased auditory nerve central synaptopathy is associated with age-related hearing loss. J Physiol 2021; 599:1833-1854. [PMID: 33450070 DOI: 10.1113/jp281014] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 01/03/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Sound information is transmitted by different subtypes of spiral ganglion neurons (SGN) from the ear to the brain. Selective damage of SGN peripheral synapses (cochlear synaptopathy) is widely recognized as one of the primary mechanisms of hearing loss, whereas the mechanisms at the SGN central synapses remain unclear. We report that different subtypes of SGN central synapses converge at different ratios onto individual target cochlear nucleus neurons with distinct physiological properties, and show biased morphological and physiological changes during age-related hearing loss (ARHL). The results reveal a new dimension in cochlear nucleus neural circuitry that systematically reassembles and processes auditory information from different SGN subtypes, which is altered during ageing and probably contributes to the development of ARHL. In addition to known cochlear synaptopathy, the present study shows that SGN central synapses are also pathologically changed during ageing, which collectively helps us better understand the structure and function of SGNs during ARHL. ABSTRACT Sound information is transmitted from the cochlea to the brain by different subtypes of spiral ganglion neurons (SGN), which show varying degrees of vulnerability under pathological conditions. Selective cochlear synaptopathy, the preferential damage of certain subtypes of SGN peripheral synapses, has been recognized as one of the main mechanisms of hearing loss. The organization and function of the auditory nerve (AN) central synapses from different subtypes of SGNs remain unclear, including how different AN synapses reassemble onto individual neurons in the cochlear nucleus, as well as how they differentially change during hearing loss. Combining immunohistochemistry with electrophysiology, we investigated the convergence pattern and subtype-specific synaptopathy of AN synapses at the endbulb of Held, as well as the response properties of their postsynaptic bushy neurons in CBA/CaJ mice of either sex under normal hearing and age-related hearing loss (ARHL). We found that calretinin-expressing (type Ia ) and non-calretinin-expressing (type Ib /Ic ) endbulbs converged along a continuum of different ratios onto individual bushy neurons with varying physiological properties. Endbulbs degenerated during ageing in parallel with ARHL. Furthermore, the degeneration was more severe in non-calretinin-expressing synapses, which correlated with a gradual decrease in bushy neuron subpopulation predominantly innervated by these inputs. These synaptic and cellular changes were profound in middle-aged mice when their hearing thresholds were still relatively normal and prior to severe ARHL. Our findings suggest that biased AN central synaptopathy and the correlated shift in cochlear nucleus neuronal composition play significant roles in weakened auditory input and altered central auditory processing during ARHL.
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Affiliation(s)
- Meijian Wang
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, USA
| | - Chuangeng Zhang
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, USA
| | - Shengyin Lin
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, USA
| | - Yong Wang
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, USA
| | - Benjamin J Seicol
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, USA.,Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Robert W Ariss
- College of Medicine and Life Sciences, University of Toledo, Toledo, OH, USA
| | - Ruili Xie
- Department of Otolaryngology-Head and Neck Surgery, The Ohio State University, Columbus, OH, USA.,Department of Neuroscience, The Ohio State University, Columbus, OH, USA
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Microfluidic and Microscale Assays to Examine Regenerative Strategies in the Neuro Retina. MICROMACHINES 2020; 11:mi11121089. [PMID: 33316971 PMCID: PMC7763644 DOI: 10.3390/mi11121089] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/03/2020] [Accepted: 12/05/2020] [Indexed: 12/15/2022]
Abstract
Bioengineering systems have transformed scientific knowledge of cellular behaviors in the nervous system (NS) and pioneered innovative, regenerative therapies to treat adult neural disorders. Microscale systems with characteristic lengths of single to hundreds of microns have examined the development and specialized behaviors of numerous neuromuscular and neurosensory components of the NS. The visual system is comprised of the eye sensory organ and its connecting pathways to the visual cortex. Significant vision loss arises from dysfunction in the retina, the photosensitive tissue at the eye posterior that achieves phototransduction of light to form images in the brain. Retinal regenerative medicine has embraced microfluidic technologies to manipulate stem-like cells for transplantation therapies, where de/differentiated cells are introduced within adult tissue to replace dysfunctional or damaged neurons. Microfluidic systems coupled with stem cell biology and biomaterials have produced exciting advances to restore vision. The current article reviews contemporary microfluidic technologies and microfluidics-enhanced bioassays, developed to interrogate cellular responses to adult retinal cues. The focus is on applications of microfluidics and microscale assays within mammalian sensory retina, or neuro retina, comprised of five types of retinal neurons (photoreceptors, horizontal, bipolar, amacrine, retinal ganglion) and one neuroglia (Müller), but excludes the non-sensory, retinal pigmented epithelium.
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Warnecke A, Harre J, Staecker H, Prenzler N, Strunk D, Couillard‐Despres S, Romanelli P, Hollerweger J, Lassacher T, Auer D, Pachler K, Wietzorrek G, Köhl U, Lenarz T, Schallmoser K, Laner‐Plamberger S, Falk CS, Rohde E, Gimona M. Extracellular vesicles from human multipotent stromal cells protect against hearing loss after noise trauma in vivo. Clin Transl Med 2020; 10:e262. [PMID: 33377658 PMCID: PMC7752163 DOI: 10.1002/ctm2.262] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/03/2020] [Accepted: 12/06/2020] [Indexed: 12/21/2022] Open
Abstract
The lack of approved anti-inflammatory and neuroprotective therapies in otology has been acknowledged in the last decades and recent approaches are heralding a new era in the field. Extracellular vesicles (EVs) derived from human multipotent (mesenchymal) stromal cells (MSC) can be enriched in vesicular secretome fractions, which have been shown to exert effects (eg, neuroprotection and immunomodulation) of their parental cells. Hence, MSC-derived EVs may serve as novel drug candidates for several inner ear diseases. Here, we provide first evidence of a strong neuroprotective potential of human stromal cell-derived EVs on inner ear physiology. In vitro, MSC-EV preparations exerted immunomodulatory activity on T cells and microglial cells. Moreover, local application of MSC-EVs to the inner ear significantly attenuated hearing loss and protected auditory hair cells from noise-induced trauma in vivo. Thus, EVs derived from the vesicular secretome of human MSC may represent a next-generation biological drug that can exert protective therapeutic effects in a complex and nonregenerating organ like the inner ear.
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Affiliation(s)
- Athanasia Warnecke
- Department of OtorhinolaryngologyHead and Neck SurgeryHannover Medical SchoolHannoverGermany
| | - Jennifer Harre
- Department of OtorhinolaryngologyHead and Neck SurgeryHannover Medical SchoolHannoverGermany
| | - Hinrich Staecker
- Department of Otolaryngology, Head and Neck SurgeryUniversity of Kansas School of MedicineKansas CityKansas
| | - Nils Prenzler
- Department of OtorhinolaryngologyHead and Neck SurgeryHannover Medical SchoolHannoverGermany
| | - Dirk Strunk
- Institute of Experimental and Clinical Cell TherapySpinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical UniversitySalzburgAustria
| | - Sebastien Couillard‐Despres
- Institute of Experimental NeuroregenerationSpinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical UniversitySalzburgAustria
- Austrian Cluster for Tissue RegenerationViennaAustria
| | - Pasquale Romanelli
- Institute of Experimental NeuroregenerationSpinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical UniversitySalzburgAustria
| | - Julia Hollerweger
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical University (PMU)SalzburgAustria
| | - Teresa Lassacher
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical University (PMU)SalzburgAustria
| | - Daniela Auer
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical University (PMU)SalzburgAustria
| | - Karin Pachler
- Research Program “Nanovesicular Therapies,”Paracelsus Medical University (PMU)SalzburgAustria
| | - Georg Wietzorrek
- Institute of Molecular and Cellular PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Ulrike Köhl
- Institute of Cellular TherapeuticsHannover Medical School and Clinical ImmunologyUniversity Leipzig, Fraunhofer Institute for Cell Therapy and ImmunologyLeipzigGermany
| | - Thomas Lenarz
- Department of OtorhinolaryngologyHead and Neck SurgeryHannover Medical SchoolHannoverGermany
| | - Katharina Schallmoser
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical University (PMU)SalzburgAustria
- Department of Transfusion MedicineUniversity HospitalSalzburger Landeskliniken GesmbH (SALK) and Paracelsus Medical University (PMU)SalzburgAustria
| | - Sandra Laner‐Plamberger
- Department of Transfusion MedicineUniversity HospitalSalzburger Landeskliniken GesmbH (SALK) and Paracelsus Medical University (PMU)SalzburgAustria
| | - Christine S. Falk
- Institute of Transplant ImmunologyHannover Medical SchoolHannoverGermany
| | - Eva Rohde
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical University (PMU)SalzburgAustria
- Department of Transfusion MedicineUniversity HospitalSalzburger Landeskliniken GesmbH (SALK) and Paracelsus Medical University (PMU)SalzburgAustria
| | - Mario Gimona
- GMP Unit, Spinal Cord Injury and Tissue Regeneration Centre Salzburg (SCI‐TReCS)Paracelsus Medical University (PMU)SalzburgAustria
- Research Program “Nanovesicular Therapies,”Paracelsus Medical University (PMU)SalzburgAustria
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Luque M, Schrott-Fischer A, Dudas J, Pechriggl E, Brenner E, Rask-Andersen H, Liu W, Glueckert R. HCN channels in the mammalian cochlea: Expression pattern, subcellular location, and age-dependent changes. J Neurosci Res 2020; 99:699-728. [PMID: 33181864 PMCID: PMC7839784 DOI: 10.1002/jnr.24754] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/03/2023]
Abstract
Neuronal diversity in the cochlea is largely determined by ion channels. Among voltage‐gated channels, hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels open with hyperpolarization and depolarize the cell until the resting membrane potential. The functions for hearing are not well elucidated and knowledge about localization is controversial. We created a detailed map of subcellular location and co‐expression of all four HCN subunits across different mammalian species including CBA/J, C57Bl/6N, Ly5.1 mice, guinea pigs, cats, and human subjects. We correlated age‐related hearing deterioration in CBA/J and C57Bl/6N with expression levels of HCN1, −2, and −4 in individual auditory neurons from the same cohort. Spatiotemporal expression during murine postnatal development exposed HCN2 and HCN4 involvement in a critical phase of hair cell innervation. The huge diversity of subunit composition, but lack of relevant heteromeric pairing along the perisomatic membrane and axon initial segments, highlighted an active role for auditory neurons. Neuron clusters were found to be the hot spots of HCN1, −2, and −4 immunostaining. HCN channels were also located in afferent and efferent fibers of the sensory epithelium. Age‐related changes on HCN subtype expression were not uniform among mice and could not be directly correlated with audiometric data. The oldest mice groups revealed HCN channel up‐ or downregulation, depending on the mouse strain. The unexpected involvement of HCN channels in outer hair cell function where HCN3 overlaps prestin location emphasized the importance for auditory function. A better understanding may open up new possibilities to tune neuronal responses evoked through electrical stimulation by cochlear implants.
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Affiliation(s)
- Maria Luque
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Jozsef Dudas
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elisabeth Pechriggl
- Department of Anatomy, Histology & Embryology, Division of Clinical & Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria
| | - Erich Brenner
- Department of Anatomy, Histology & Embryology, Division of Clinical & Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Wei Liu
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Rudolf Glueckert
- Department of Otorhinolaryngology, Medical University of Innsbruck, Innsbruck, Austria.,Tirol Kliniken, University Clinics Innsbruck, Innsbruck, Austria
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Molecular Mechanisms and Biological Functions of Autophagy for Genetics of Hearing Impairment. Genes (Basel) 2020; 11:genes11111331. [PMID: 33187328 PMCID: PMC7697636 DOI: 10.3390/genes11111331] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/03/2020] [Accepted: 11/05/2020] [Indexed: 02/08/2023] Open
Abstract
The etiology of hearing impairment following cochlear damage can be caused by many factors, including congenital or acquired onset, ototoxic drugs, noise exposure, and aging. Regardless of the many different etiologies, a common pathologic change is auditory cell death. It may be difficult to explain hearing impairment only from the aspect of cell death including apoptosis, necrosis, or necroptosis because the level of hearing loss varies widely. Therefore, we focused on autophagy as an intracellular phenomenon functionally competing with cell death. Autophagy is a dynamic lysosomal degradation and recycling system in the eukaryotic cell, mandatory for controlling the balance between cell survival and cell death induced by cellular stress, and maintaining homeostasis of postmitotic cells, including hair cells (HCs) and spiral ganglion neurons (SGNs) in the inner ear. Autophagy is considered a candidate for the auditory cell fate decision factor, whereas autophagy deficiency could be one of major causes of hearing impairment. In this paper, we review the molecular mechanisms and biologic functions of autophagy in the auditory system and discuss the latest research concerning autophagy-related genes and sensorineural hearing loss to gain insight into the role of autophagic mechanisms in inner-ear disorders.
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Wood MB, Nowak N, Mull K, Goldring A, Lehar M, Fuchs PA. Acoustic Trauma Increases Ribbon Number and Size in Outer Hair Cells of the Mouse Cochlea. J Assoc Res Otolaryngol 2020; 22:19-31. [PMID: 33151428 PMCID: PMC7822997 DOI: 10.1007/s10162-020-00777-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/19/2020] [Indexed: 01/01/2023] Open
Abstract
Outer hair cells (OHCs) in the mouse cochlea are contacted by up to three type II afferent boutons. On average, only half of these are postsynaptic to presynaptic ribbons. Mice of both sexes were subjected to acoustic trauma that produced a threshold shift of 44.2 ± 9.1 dB 7 days after exposure. Ribbon synapses of OHCs were quantified in post-trauma and littermate controls using immunolabeling of CtBP2. Visualization with virtual reality was used to determine 3-D cytoplasmic localization of CtBP2 puncta to the synaptic pole of OHCs. Acoustic trauma was associated with a statistically significant increase in the number of synaptic ribbons per OHC. Serial section TEM was carried out on similarly treated mice. This also showed a significant increase in the number of ribbons in post-trauma OHCs, as well as a significant increase in ribbon volume compared to ribbons in control OHCs. An increase in OHC ribbon synapses after acoustic trauma is a novel observation that has implications for OHC:type II afferent signaling. A mathematical model showed that the observed increase in OHC ribbons considered alone could produce a significant increase in action potentials among type II afferent neurons during strong acoustic stimulation.
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Affiliation(s)
- Megan B Wood
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA.
| | - Nathaniel Nowak
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
| | - Keira Mull
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
| | - Adam Goldring
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA.,Sutter Instrument, Co. 1 Digital Drive, Novato, CA, 94949, USA
| | - Mohamed Lehar
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
| | - Paul Albert Fuchs
- Department of Otolaryngology - Head and Neck, Surgery, Johns Hopkins University School of Medicine, 820 Richard Starr Ross Research Building, 720 Rutland Ave, Baltimore, MD, 21205, USA
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44
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Research Progress of Hair Cell Protection Mechanism. Neural Plast 2020; 2020:8850447. [PMID: 33133179 PMCID: PMC7568815 DOI: 10.1155/2020/8850447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/16/2020] [Accepted: 09/30/2020] [Indexed: 11/17/2022] Open
Abstract
How to prevent and treat hearing-related diseases through the protection of hair cells (HCs) is the focus in the field of hearing in recent years. Hearing loss caused by dysfunction or loss of HCs is the main cause of hearing diseases. Therefore, clarifying the related mechanisms of HC development, apoptosis, protection, and regeneration is the main goal of current hearing research. This review introduces the latest research on mechanism of HC protection and regeneration.
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45
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Ghosh S, Lewis MB, Walters BJ. Comparison of ethylenediaminetetraacetic acid and rapid decalcificier solution for studying human temporal bones by immunofluorescence. Laryngoscope Investig Otolaryngol 2020; 5:919-927. [PMID: 33134540 PMCID: PMC7585256 DOI: 10.1002/lio2.449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/21/2020] [Accepted: 08/03/2020] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES The pervasiveness of hearing loss and the development of new potential therapeutic approaches have led to increased animal studies of the inner ear. However, translational relevance of such studies depends upon verification of protein localization data in human samples. Cadavers used for anatomical education provide a potential research resource, but are limiting due to difficulties in accessing sensory tissues from the dense temporal bones. This study seeks to reduce the often months-long process of decalcification and improve immunofluorescent staining of human cadaveric temporal bones for research use. METHODS Temporal bones were decalcified in either (a) hydrochloric acid-containing RDO solution for 2 days followed by 0.5 M ethylenediaminetetraacetic acid (EDTA) for 3 to 5 additional days, or (b) 0.5 M EDTA alone for 2 to 4 weeks. Image-iT FX signal enhancer (ISE) was used to improve immunofluorescent signal-to-noise ratios. RESULTS The data indicate that both methods speed decalcification and allow for immunolabeling of the extranuclear proteins neurofilament (heavy chain), myosin VIIa, oncomodulin and prestin. However, RDO decalcification was more likely to alter structural morphology of sensory tissues and hindered effective labeling of the nuclear proteins SRY-box transcription factor 2 and GATA binding protein 3. CONCLUSIONS Although both approaches allow for rapid decalcification, EDTA appears superior to RDO for preserving cytoarchitecture and immunogenicity. LEVEL OF EVIDENCE NA.
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Affiliation(s)
- Sumana Ghosh
- Department of Neurobiology and Anatomical SciencesUniversity of Mississippi Medical CenterJacksonMississippiUSA
| | - Mark B. Lewis
- Department of Neurobiology and Anatomical SciencesUniversity of Mississippi Medical CenterJacksonMississippiUSA
| | - Bradley J. Walters
- Department of Neurobiology and Anatomical SciencesUniversity of Mississippi Medical CenterJacksonMississippiUSA
- Department Otolaryngology—Head and Neck SurgeryUniversity of Mississippi Medical CenterJacksonMississippiUSA
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46
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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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47
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Frick C, Fink S, Schmidbauer D, Rousset F, Eickhoff H, Tropitzsch A, Kramer B, Senn P, Glueckert R, Rask-Andersen H, Wiesmüller KH, Löwenheim H, Müller M. Age-Dependency of Neurite Outgrowth in Postnatal Mouse Cochlear Spiral Ganglion Explants. Brain Sci 2020; 10:brainsci10090580. [PMID: 32839381 PMCID: PMC7564056 DOI: 10.3390/brainsci10090580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 12/22/2022] Open
Abstract
Background: The spatial gap between cochlear implants (CIs) and the auditory nerve limits frequency selectivity as large populations of spiral ganglion neurons (SGNs) are electrically stimulated synchronously. To improve CI performance, a possible strategy is to promote neurite outgrowth toward the CI, thereby allowing a discrete stimulation of small SGN subpopulations. Brain-derived neurotrophic factor (BDNF) is effective to stimulate neurite outgrowth from SGNs. Method: TrkB (tropomyosin receptor kinase B) agonists, BDNF, and five known small-molecule BDNF mimetics were tested for their efficacy in stimulating neurite outgrowth in postnatal SGN explants. To modulate Trk receptor-mediated effects, TrkB and TrkC ligands were scavenged by an excess of recombinant receptor proteins. The pan-Trk inhibitor K252a was used to block Trk receptor actions. Results: THF (7,8,3′-trihydroxyflavone) partly reproduced the BDNF effect in postnatal day 7 (P7) mouse cochlear spiral ganglion explants (SGEs), but failed to show effectiveness in P4 SGEs. During the same postnatal period, spontaneous and BDNF-stimulated neurite outgrowth increased. The increased neurite outgrowth in P7 SGEs was not caused by the TrkB/TrkC ligands, BDNF and neurotrophin-3 (NT-3). Conclusions: The age-dependency of induction of neurite outgrowth in SGEs was very likely dependent on presently unidentified factors and/or molecular mechanisms which may also be decisive for the age-dependent efficacy of the small-molecule TrkB receptor agonist THF.
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Affiliation(s)
- Claudia Frick
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
- Department of Microbiome Science, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Stefan Fink
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
- Correspondence: ; Tel.: +49-7071-2988192
| | - Dominik Schmidbauer
- Inner Ear Laboratory Innsbruck, Medical University Innsbruck, 6020 Innsbruck, Austria; (D.S.); (R.G.)
| | - Francis Rousset
- The Inner Ear & Olfaction Lab, Department of Clinical Neurosciences, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland; (F.R.); (P.S.)
| | - Holger Eickhoff
- EMC Microcollections GmbH, 72070 Tübingen, Germany; (H.E.); (K.-H.W.)
| | - Anke Tropitzsch
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
| | - Benedikt Kramer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
- Department of Otolaryngology, Head and Neck Surgery, University Hospital Mannheim, 68167 Mannheim, Germany
| | - Pascal Senn
- The Inner Ear & Olfaction Lab, Department of Clinical Neurosciences, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland; (F.R.); (P.S.)
| | - Rudolf Glueckert
- Inner Ear Laboratory Innsbruck, Medical University Innsbruck, 6020 Innsbruck, Austria; (D.S.); (R.G.)
- Tirol Kliniken Innsbruck, University Clinic of Otolaryngology, 6020 Innsbruck, Austria
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, University of Uppsala, 751 85 Uppsala, Sweden;
| | | | - Hubert Löwenheim
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
| | - Marcus Müller
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
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The Purinergic Receptor P2rx3 is Required for Spiral Ganglion Neuron Branch Refinement during Development. eNeuro 2020; 7:ENEURO.0179-20.2020. [PMID: 32675174 PMCID: PMC7418533 DOI: 10.1523/eneuro.0179-20.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/03/2020] [Accepted: 07/08/2020] [Indexed: 12/18/2022] Open
Abstract
The mammalian cochlea undergoes a highly dynamic process of growth and innervation during development. This process includes spiral ganglion neuron (SGN) branch refinement, a process whereby Type I SGNs undergo a phase of “debranching” before forming unramified synaptic contacts with inner hair cells. Using Sox2CreERT2 and R26RtdTomato as a strategy to genetically label individual SGNs in mice of both sexes, we report on both a time course of SGN branch refinement and a role for P2rx3 in this process. P2rx3 is an ionotropic ATP receptor that was recently implicated in outer hair cell spontaneous activity and Type II SGN synapse development (Ceriani et al., 2019), but its function in Type I SGN development is unknown. Here, we demonstrate that P2rx3 is expressed by Type I SGNs and hair cells during developmental periods that coincide with SGN branching refinement. P2rx3 null mice show SGNs with more complex branching patterns on their peripheral synaptic terminals and near their cell bodies around the time of birth. Loss of P2rx3 does not appear to confer general changes in axon outgrowth or hair cell formation, and alterations in branching complexity appear to mostly recover by postnatal day (P)6. However, when we examined the distribution of Type I SGN subtypes using antibodies that bind Calb2, Calb1, and Pou4f1, we found that P2rx3 null mice showed an increased proportion of SGNs that express Calb2. These data suggest P2rx3 may be necessary for normal Type I SGN differentiation in addition to serving a role in branch refinement.
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Seist R, Tong M, Landegger LD, Vasilijic S, Hyakusoku H, Katsumi S, McKenna CE, Edge ASB, Stankovic KM. Regeneration of Cochlear Synapses by Systemic Administration of a Bisphosphonate. Front Mol Neurosci 2020; 13:87. [PMID: 32765216 PMCID: PMC7381223 DOI: 10.3389/fnmol.2020.00087] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022] Open
Abstract
Sensorineural hearing loss (SNHL) caused by noise exposure and attendant loss of glutamatergic synapses between cochlear spiral ganglion neurons (SGNs) and hair cells is the most common sensory deficit worldwide. We show here that systemic administration of a bisphosphonate to mice 24 h after synaptopathic noise exposure regenerated synapses between inner hair cells and SGNs and restored cochlear function. We further demonstrate that this effect is mediated by inhibition of the mevalonate pathway. These results are highly significant because they suggest that bisphosphonates could reverse cochlear synaptopathy for the treatment of SNHL.
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Affiliation(s)
- Richard Seist
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
- Department of Otorhinolaryngology-Head and Neck Surgery, Paracelsus Medical University, Salzburg, Austria
| | - Mingjie Tong
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
| | - Lukas D. Landegger
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
- Department of Otorhinolaryngology-Head and Neck Surgery, Medical University of Vienna, Vienna, Austria
| | - Sasa Vasilijic
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
| | - Hiroshi Hyakusoku
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
- Department of Otorhinolaryngology, Yokosuka Kyosai Hospital, Kanagawa, Japan
| | - Sachiyo Katsumi
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
| | - Charles E. McKenna
- Department of Chemistry, University of Southern California, Los Angeles, CA, United States
| | - Albert S. B. Edge
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
- Speech and Hearing Bioscience and Technology Program, Harvard Medical School, Boston, MA, United States
- Harvard Stem Cell Institute, Cambridge, MA, United States
| | - Konstantina M. Stankovic
- Eaton-Peabody Laboratories, Department of Otolaryngology – Head and Neck Surgery, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology – Head and Neck Surgery, Harvard Medical School, Boston, MA, United States
- Speech and Hearing Bioscience and Technology Program, Harvard Medical School, Boston, MA, United States
- Harvard Stem Cell Institute, Cambridge, MA, United States
- Program in Therapeutic Science, Harvard Medical School, Boston, MA, United States
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50
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Grandi FC, De Tomasi L, Mustapha M. Single-Cell RNA Analysis of Type I Spiral Ganglion Neurons Reveals a Lmx1a Population in the Cochlea. Front Mol Neurosci 2020; 13:83. [PMID: 32523514 PMCID: PMC7261882 DOI: 10.3389/fnmol.2020.00083] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/24/2020] [Indexed: 12/13/2022] Open
Abstract
In the mature cochlea, each inner hair cell (IHC) is innervated by multiple spiral ganglion neurons of type I (SGNI). SGNIs are morphologically and electro-physiologically diverse. Also, they differ in their susceptibility to noise insult. However, the molecular underpinnings of their identity and physiological differences remain poorly understood. In this study, we developed a novel triple transgenic mouse, which enabled the isolation of pure populations of SGNIs and the analysis of a 96-gene panel via single-cell qPCR. We found three distinct populations of Type I SGNs, which were marked by their exclusive expression of Lmx1a, Slc4a4, or Mfap4/Fzd2, respectively, at postnatal days P3, P8, and P12. Our data suggest that afferent SGN subtypes are established genetically before the onset of hearing and that the expression of key physiological markers, such as ion channels, is heterogeneous and may be underlying the heterogeneous firing proprieties of SGNIs.
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Affiliation(s)
| | - Lara De Tomasi
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Mirna Mustapha
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom.,Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
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