1
|
Pyott SJ, Pavlinkova G, Yamoah EN, Fritzsch B. Harmony in the Molecular Orchestra of Hearing: Developmental Mechanisms from the Ear to the Brain. Annu Rev Neurosci 2024; 47:1-20. [PMID: 38360566 DOI: 10.1146/annurev-neuro-081423-093942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Auditory processing in mammals begins in the peripheral inner ear and extends to the auditory cortex. Sound is transduced from mechanical stimuli into electrochemical signals of hair cells, which relay auditory information via the primary auditory neurons to cochlear nuclei. Information is subsequently processed in the superior olivary complex, lateral lemniscus, and inferior colliculus and projects to the auditory cortex via the medial geniculate body in the thalamus. Recent advances have provided valuable insights into the development and functioning of auditory structures, complementing our understanding of the physiological mechanisms underlying auditory processing. This comprehensive review explores the genetic mechanisms required for auditory system development from the peripheral cochlea to the auditory cortex. We highlight transcription factors and other genes with key recurring and interacting roles in guiding auditory system development and organization. Understanding these gene regulatory networks holds promise for developing novel therapeutic strategies for hearing disorders, benefiting millions globally.
Collapse
Affiliation(s)
- Sonja J Pyott
- Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Groningen, Graduate School of Medical Sciences, and Research School of Behavioral and Cognitive Neurosciences, University of Groningen, Groningen, The Netherlands
| | - Gabriela Pavlinkova
- Laboratory of Molecular Pathogenetics, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Nevada, USA
| | - Bernd Fritzsch
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, Nebraska, USA;
| |
Collapse
|
2
|
You D, Ni W, Huang Y, Zhou Q, Zhang Y, Jiang T, Chen Y, Li W. The proper timing of Atoh1 expression is pivotal for hair cell subtype differentiation and the establishment of inner ear function. Cell Mol Life Sci 2023; 80:349. [PMID: 37930405 PMCID: PMC10628023 DOI: 10.1007/s00018-023-04947-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: 07/05/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 11/07/2023]
Abstract
Atoh1 overexpression is essential for hair cell (HC) regeneration in the sensory epithelium of mammalian auditory and vestibular organs. However, Atoh1 overexpression alone cannot induce fully mature and functional HCs in the mammalian inner ear. In the current study, we investigated the effect of Atoh1 constitutive overexpression in native HCs by manipulating Atoh1 expression at different developmental stages. We demonstrated that constitutive overexpression of Atoh1 in native vestibular HCs did not affect cell survival but did impair vestibular function by interfering with the subtype differentiation of HCs and hair bundle development. In contrast, Atoh1 overexpression in cochlear HCs impeded their maturation, eventually leading to gradual HC loss in the cochlea and hearing dysfunction. Our study suggests that time-restricted Atoh1 expression is essential for the differentiation and survival of HCs in the inner ear, and this is pivotal for both hearing and vestibular function re-establishment through Atoh1 overexpression-induced HC regeneration strategies.
Collapse
Affiliation(s)
- Dan You
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Wenli Ni
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Yikang Huang
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Qin Zhou
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Yanping Zhang
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Tao Jiang
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Yan Chen
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China.
| | - Wenyan Li
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China.
| |
Collapse
|
3
|
Kelley MW. Cochlear Development; New Tools and Approaches. Front Cell Dev Biol 2022; 10:884240. [PMID: 35813214 PMCID: PMC9260282 DOI: 10.3389/fcell.2022.884240] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/19/2022] [Indexed: 12/21/2022] Open
Abstract
The sensory epithelium of the mammalian cochlea, the organ of Corti, is comprised of at least seven unique cell types including two functionally distinct types of mechanosensory hair cells. All of the cell types within the organ of Corti are believed to develop from a population of precursor cells referred to as prosensory cells. Results from previous studies have begun to identify the developmental processes, lineage restrictions and signaling networks that mediate the specification of many of these cell types, however, the small size of the organ and the limited number of each cell type has hampered progress. Recent technical advances, in particular relating to the ability to capture and characterize gene expression at the single cell level, have opened new avenues for understanding cellular specification in the organ of Corti. This review will cover our current understanding of cellular specification in the cochlea, discuss the most commonly used methods for single cell RNA sequencing and describe how results from a recent study using single cell sequencing provided new insights regarding cellular specification.
Collapse
|
4
|
Elliott KL, Fritzsch B, Yamoah EN, Zine A. Age-Related Hearing Loss: Sensory and Neural Etiology and Their Interdependence. Front Aging Neurosci 2022; 14:814528. [PMID: 35250542 PMCID: PMC8891613 DOI: 10.3389/fnagi.2022.814528] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 01/03/2022] [Indexed: 12/19/2022] Open
Abstract
Age-related hearing loss (ARHL) is a common, increasing problem for older adults, affecting about 1 billion people by 2050. We aim to correlate the different reductions of hearing from cochlear hair cells (HCs), spiral ganglion neurons (SGNs), cochlear nuclei (CN), and superior olivary complex (SOC) with the analysis of various reasons for each one on the sensory deficit profiles. Outer HCs show a progressive loss in a basal-to-apical gradient, and inner HCs show a loss in a apex-to-base progression that results in ARHL at high frequencies after 70 years of age. In early neonates, SGNs innervation of cochlear HCs is maintained. Loss of SGNs results in a considerable decrease (~50% or more) of cochlear nuclei in neonates, though the loss is milder in older mice and humans. The dorsal cochlear nuclei (fusiform neurons) project directly to the inferior colliculi while most anterior cochlear nuclei reach the SOC. Reducing the number of neurons in the medial nucleus of the trapezoid body (MNTB) affects the interactions with the lateral superior olive to fine-tune ipsi- and contralateral projections that may remain normal in mice, possibly humans. The inferior colliculi receive direct cochlear fibers and second-order fibers from the superior olivary complex. Loss of the second-order fibers leads to hearing loss in mice and humans. Although ARHL may arise from many complex causes, HC degeneration remains the more significant problem of hearing restoration that would replace the cochlear implant. The review presents recent findings of older humans and mice with hearing loss.
Collapse
Affiliation(s)
- Karen L. Elliott
- Department of Biology, University of Iowa, Iowa City, IA, United States
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, United States
- *Correspondence: Bernd Fritzsch
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Azel Zine
- LBN, Laboratory of Bioengineering and Nanoscience, University of Montpellier, Montpellier, France
| |
Collapse
|
5
|
Liu W, Johansson Å, Rask-Andersen H, Rask-Andersen M. A combined genome-wide association and molecular study of age-related hearing loss in H. sapiens. BMC Med 2021; 19:302. [PMID: 34847940 PMCID: PMC8638543 DOI: 10.1186/s12916-021-02169-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 10/21/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Sensorineural hearing loss is one of the most common sensory deficiencies. However, the molecular contribution to age-related hearing loss is not fully elucidated. METHODS We performed genome-wide association studies (GWAS) for hearing loss-related traits in the UK Biobank (N = 362,396) and selected a high confidence set of ten hearing-associated gene products for staining in human cochlear samples: EYA4, LMX1A, PTK2/FAK, UBE3B, MMP2, SYNJ2, GRM5, TRIOBP, LMO-7, and NOX4. RESULTS All proteins were found to be expressed in human cochlear structures. Our findings illustrate cochlear structures that mediate mechano-electric transduction of auditory stimuli, neuronal conductance, and neuronal plasticity to be involved in age-related hearing loss. CONCLUSIONS Our results suggest common genetic variation to influence structural resilience to damage as well as cochlear recovery after trauma, which protect against accumulated damage to cochlear structures and the development of hearing loss over time.
Collapse
Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head & Neck Surgery, Uppsala University, SE-751 85, Uppsala, Sweden
| | - Åsa Johansson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Section of Otorhinolaryngology and Head & Neck Surgery, Uppsala University, SE-751 85, Uppsala, Sweden.
| | - Mathias Rask-Andersen
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
6
|
Yu Y, Yang J, Luan F, Gu G, Zhao R, Wang Q, Dong Z, Tang J, Wang W, Sun J, Lv P, Zhang H, Wang C. Sensorineural Hearing Loss and Mitochondrial Apoptosis of Cochlear Spiral Ganglion Neurons in Fibroblast Growth Factor 13 Knockout Mice. Front Cell Neurosci 2021; 15:658586. [PMID: 34220452 PMCID: PMC8242186 DOI: 10.3389/fncel.2021.658586] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/26/2021] [Indexed: 12/17/2022] Open
Abstract
Deafness is known to occur in more than 400 syndromes and accounts for almost 30% of hereditary hearing loss. The molecular mechanisms underlying such syndromic deafness remain unclear. Furthermore, deafness has been a common feature in patients with three main syndromes, the BÖrjeson-Forssman-Lehmann syndrome, Wildervanck syndrome, and Congenital Generalized Hirsutism, all of which are characterized by loss-of-function mutations in the Fgf13 gene. Whether the pathogenesis of deafness in these syndromes is associated with the Fgf13 mutation is not known. To elucidate its role in auditory function, we generated a mouse line with conditional knockout of the Fgf13 gene in the inner ear (Fgf13 cKO). FGF13 is expressed predominantly in the organ of Corti, spiral ganglion neurons (SGNs), stria vascularis, and the supporting cells. Conditional knockout of the gene in the inner ear led to sensorineural deafness with low amplitude and increased latency of wave I in the auditory brainstem response test but had a normal distortion product otoacoustic emission threshold. Fgf13 deficiency resulted in decreased SGN density from the apical to the basal region without significant morphological changes and those in the number of hair cells. TUNEL and caspase-3 immunocytochemistry assays showed that apoptotic cell death mediated the loss of SGNs. Further detection of apoptotic factors through qRT-PCR suggested the activation of the mitochondrial apoptotic pathway in SGNs. Together, this study reveals a novel role for Fgf13 in auditory function, and indicates that the gene could be a potential candidate for understanding deafness. These findings may provide new perspectives on the molecular mechanisms and novel therapeutic targets for treatment deafness.
Collapse
Affiliation(s)
- Yulou Yu
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Jing Yang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Feng Luan
- Department of Otolaryngology, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Guoqiang Gu
- Department of Cardiology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ran Zhao
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Qiong Wang
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Zishan Dong
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Junming Tang
- Hubei Key Laboratory of Embryonic Stem Cell Research, Hubei University of Medicine, Shiyan, China
| | - Wei Wang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Jinpeng Sun
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ping Lv
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Hailin Zhang
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Chuan Wang
- The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| |
Collapse
|
7
|
Elliott KL, Pavlinkova G, Chizhikov VV, Yamoah EN, Fritzsch B. Neurog1, Neurod1, and Atoh1 are essential for spiral ganglia, cochlear nuclei, and cochlear hair cell development. Fac Rev 2021; 10:47. [PMID: 34131657 PMCID: PMC8170689 DOI: 10.12703/r/10-47] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We review the molecular basis of three related basic helix–loop–helix (bHLH) genes (Neurog1, Neurod1, and Atoh1) and upstream regulators Eya1/Six1, Sox2, Pax2, Gata3, Fgfr2b, Foxg1, and Lmx1a/b during the development of spiral ganglia, cochlear nuclei, and cochlear hair cells. Neuronal development requires early expression of Neurog1, followed by its downstream target Neurod1, which downregulates Atoh1 expression. In contrast, hair cells and cochlear nuclei critically depend on Atoh1 and require Neurod1 and Neurog1 expression for various aspects of development. Several experiments show a partial uncoupling of Atoh1/Neurod1 (spiral ganglia and cochlea) and Atoh1/Neurog1/Neurod1 (cochlear nuclei). In this review, we integrate the cellular and molecular mechanisms that regulate the development of auditory system and provide novel insights into the restoration of hearing loss, beyond the limited generation of lost sensory neurons and hair cells.
Collapse
Affiliation(s)
- Karen L Elliott
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Gabriela Pavlinkova
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czechia
| | - Victor V Chizhikov
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, USA
| |
Collapse
|
8
|
Elliott KL, Pavlínková G, Chizhikov VV, Yamoah EN, Fritzsch B. Development in the Mammalian Auditory System Depends on Transcription Factors. Int J Mol Sci 2021; 22:ijms22084189. [PMID: 33919542 PMCID: PMC8074135 DOI: 10.3390/ijms22084189] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022] Open
Abstract
We review the molecular basis of several transcription factors (Eya1, Sox2), including the three related genes coding basic helix–loop–helix (bHLH; see abbreviations) proteins (Neurog1, Neurod1, Atoh1) during the development of spiral ganglia, cochlear nuclei, and cochlear hair cells. Neuronal development requires Neurog1, followed by its downstream target Neurod1, to cross-regulate Atoh1 expression. In contrast, hair cells and cochlear nuclei critically depend on Atoh1 and require Neurod1 expression for interactions with Atoh1. Upregulation of Atoh1 following Neurod1 loss changes some vestibular neurons’ fate into “hair cells”, highlighting the significant interplay between the bHLH genes. Further work showed that replacing Atoh1 by Neurog1 rescues some hair cells from complete absence observed in Atoh1 null mutants, suggesting that bHLH genes can partially replace one another. The inhibition of Atoh1 by Neurod1 is essential for proper neuronal cell fate, and in the absence of Neurod1, Atoh1 is upregulated, resulting in the formation of “intraganglionic” HCs. Additional genes, such as Eya1/Six1, Sox2, Pax2, Gata3, Fgfr2b, Foxg1, and Lmx1a/b, play a role in the auditory system. Finally, both Lmx1a and Lmx1b genes are essential for the cochlear organ of Corti, spiral ganglion neuron, and cochlear nuclei formation. We integrate the mammalian auditory system development to provide comprehensive insights beyond the limited perception driven by singular investigations of cochlear neurons, cochlear hair cells, and cochlear nuclei. A detailed analysis of gene expression is needed to understand better how upstream regulators facilitate gene interactions and mammalian auditory system development.
Collapse
Affiliation(s)
- Karen L. Elliott
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA;
| | - Gabriela Pavlínková
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czechia;
| | - Victor V. Chizhikov
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA;
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV 89557, USA;
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA;
- Correspondence:
| |
Collapse
|
9
|
Ding Y, Meng W, Kong W, He Z, Chai R. The Role of FoxG1 in the Inner Ear. Front Cell Dev Biol 2020; 8:614954. [PMID: 33344461 PMCID: PMC7744801 DOI: 10.3389/fcell.2020.614954] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022] Open
Abstract
Sensorineural deafness is mainly caused by damage to the tissues of the inner ear, and hearing impairment has become an increasingly serious global health problem. When the inner ear is abnormally developed or is damaged by inflammation, ototoxic drugs, or blood supply disorders, auditory signal transmission is inhibited resulting in hearing loss. Forkhead box G1 (FoxG1) is an important nuclear transcriptional regulator, which is related to the differentiation, proliferation, development, and survival of cells in the brain, telencephalon, inner ear, and other tissues. Previous studies have shown that when FoxG1 is abnormally expressed, the development and function of inner ear hair cells is impaired. This review discusses the role and regulatory mechanism of FoxG1 in inner ear tissue from various aspects – such as the effect on inner ear development, the maintenance of inner ear structure and function, and its role in the inner ear when subjected to various stimulations or injuries – in order to explain the potential significance of FoxG1 as a new target for the treatment of hearing loss.
Collapse
Affiliation(s)
- Yanyan Ding
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Meng
- Department of Otolaryngology Head and Neck, Nanjing Tongren Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Weijia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zuhong He
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 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 of Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| |
Collapse
|
10
|
He L, Guo JY, Liu K, Wang GP, Gong SS. Research progress on flat epithelium of the inner ear. Physiol Res 2020; 69:775-785. [PMID: 32901490 DOI: 10.33549/physiolres.934447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Sensorineural hearing loss and vertigo, resulting from lesions in the sensory epithelium of the inner ear, have a high incidence worldwide. The sensory epithelium of the inner ear may exhibit extreme degeneration and is transformed to flat epithelium (FE) in humans and mice with profound sensorineural hearing loss and/or vertigo. Various factors, including ototoxic drugs, noise exposure, aging, and genetic defects, can induce FE. Both hair cells and supporting cells are severely damaged in FE, and the normal cytoarchitecture of the sensory epithelium is replaced by a monolayer of very thin, flat cells of irregular contour. The pathophysiologic mechanism of FE is unclear but involves robust cell division. The cellular origin of flat cells in FE is heterogeneous; they may be transformed from supporting cells that have lost some features of supporting cells (dedifferentiation) or may have migrated from the flanking region. The epithelial-mesenchymal transition may play an important role in this process. The treatment of FE is challenging given the severe degeneration and loss of both hair cells and supporting cells. Cochlear implant or vestibular prosthesis implantation, gene therapy, and stem cell therapy show promise for the treatment of FE, although many challenges remain to be overcome.
Collapse
Affiliation(s)
- L He
- Department of Otolaryngology-Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China. ,
| | | | | | | | | |
Collapse
|
11
|
Li J, Zhang T, Ramakrishnan A, Fritzsch B, Xu J, Wong EYM, Loh YHE, Ding J, Shen L, Xu PX. Dynamic changes in cis-regulatory occupancy by Six1 and its cooperative interactions with distinct cofactors drive lineage-specific gene expression programs during progressive differentiation of the auditory sensory epithelium. Nucleic Acids Res 2020; 48:2880-2896. [PMID: 31956913 PMCID: PMC7102962 DOI: 10.1093/nar/gkaa012] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/16/2019] [Accepted: 01/17/2020] [Indexed: 12/23/2022] Open
Abstract
The transcription factor Six1 is essential for induction of sensory cell fate and formation of auditory sensory epithelium, but how it activates gene expression programs to generate distinct cell-types remains unknown. Here, we perform genome-wide characterization of Six1 binding at different stages of auditory sensory epithelium development and find that Six1-binding to cis-regulatory elements changes dramatically at cell-state transitions. Intriguingly, Six1 pre-occupies enhancers of cell-type-specific regulators and effectors before their expression. We demonstrate in-vivo cell-type-specific activity of Six1-bound novel enhancers of Pbx1, Fgf8, Dusp6, Vangl2, the hair-cell master regulator Atoh1 and a cascade of Atoh1's downstream factors, including Pou4f3 and Gfi1. A subset of Six1-bound sites carry consensus-sequences for its downstream factors, including Atoh1, Gfi1, Pou4f3, Gata3 and Pbx1, all of which physically interact with Six1. Motif analysis identifies RFX/X-box as one of the most significantly enriched motifs in Six1-bound sites, and we demonstrate that Six1-RFX proteins cooperatively regulate gene expression through binding to SIX:RFX-motifs. Six1 targets a wide range of hair-bundle regulators and late Six1 deletion disrupts hair-bundle polarity. This study provides a mechanistic understanding of how Six1 cooperates with distinct cofactors in feedforward loops to control lineage-specific gene expression programs during progressive differentiation of the auditory sensory epithelium.
Collapse
Affiliation(s)
- Jun Li
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ting Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Aarthi Ramakrishnan
- Department of Neurosciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa, IA 52242-1324
| | - Jinshu Xu
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Elaine Y M Wong
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yong-Hwee Eddie Loh
- Department of Neurosciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jianqiang Ding
- Department of Infectious Diseases, Shunde Hospital, Southern Medical University, Shunde 528308, Guangdong, China
| | - Li Shen
- Department of Neurosciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Pin-Xian Xu
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.,Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| |
Collapse
|
12
|
Yamoah EN, Li M, Shah A, Elliott KL, Cheah K, Xu PX, Phillips S, Young SM, Eberl DF, Fritzsch B. Using Sox2 to alleviate the hallmarks of age-related hearing loss. Ageing Res Rev 2020; 59:101042. [PMID: 32173536 PMCID: PMC7261488 DOI: 10.1016/j.arr.2020.101042] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/07/2023]
Abstract
Age-related hearing loss (ARHL) is the most prevalent sensory deficit. ARHL reduces the quality of life of the growing population, setting seniors up for the enhanced mental decline. The size of the needy population, the structural deficit, and a likely research strategy for effective treatment of chronic neurosensory hearing in the elderly are needed. Although there has been profound advancement in auditory regenerative research, there remain multiple challenges to restore hearing loss. Thus, additional investigations are required, using novel tools. We propose how the (1) flat epithelium, remaining after the organ of Corti has deteriorated, can be converted to the repaired-sensory epithelium, using Sox2. This will include (2) developing an artificial gene regulatory network transmitted by (3) large viral vectors to the flat epithelium to stimulate remnants of the organ of Corti to restore hair cells. We hope to unite with our proposal toward the common goal, eventually restoring a functional human hearing organ by transforming the flat epithelial cells left after the organ of Corti loss.
Collapse
Affiliation(s)
- Ebenezer N Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, USA
| | - Mark Li
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, USA
| | - Anit Shah
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, USA
| | - Karen L Elliott
- Department of Biology, CLAS, University of Iowa, Iowa City, USA
| | - Kathy Cheah
- Department of Biochemistry, Hong Kong University, Hong Kong, China
| | - Pin-Xian Xu
- Department of Biochemistry, Hong Kong University, Hong Kong, China
| | - Stacia Phillips
- Department of Biochemistry, Hong Kong University, Hong Kong, China
| | - Samuel M Young
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, USA; Department of Otolaryngology, Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
| | - Daniel F Eberl
- Department of Biology, CLAS, University of Iowa, Iowa City, USA
| | - Bernd Fritzsch
- Department of Biology, CLAS, University of Iowa, Iowa City, USA.
| |
Collapse
|
13
|
Zhang S, Zhang Y, Dong Y, Guo L, Zhang Z, Shao B, Qi J, Zhou H, Zhu W, Yan X, Hong G, Zhang L, Zhang X, Tang M, Zhao C, Gao X, Chai R. Knockdown of Foxg1 in supporting cells increases the trans-differentiation of supporting cells into hair cells in the neonatal mouse cochlea. Cell Mol Life Sci 2020; 77:1401-1419. [PMID: 31485717 PMCID: PMC7113235 DOI: 10.1007/s00018-019-03291-2] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 08/08/2019] [Accepted: 08/28/2019] [Indexed: 12/17/2022]
Abstract
Foxg1 is one of the forkhead box genes that are involved in morphogenesis, cell fate determination, and proliferation, and Foxg1 was previously reported to be required for morphogenesis of the mammalian inner ear. However, Foxg1 knock-out mice die at birth, and thus the role of Foxg1 in regulating hair cell (HC) regeneration after birth remains unclear. Here we used Sox2CreER/+ Foxg1loxp/loxp mice and Lgr5-EGFPCreER/+ Foxg1loxp/loxp mice to conditionally knock down Foxg1 specifically in Sox2+ SCs and Lgr5+ progenitors, respectively, in neonatal mice. We found that Foxg1 conditional knockdown (cKD) in Sox2+ SCs and Lgr5+ progenitors at postnatal day (P)1 both led to large numbers of extra HCs, especially extra inner HCs (IHCs) at P7, and these extra IHCs with normal hair bundles and synapses could survive at least to P30. The EdU assay failed to detect any EdU+ SCs, while the SC number was significantly decreased in Foxg1 cKD mice, and lineage tracing data showed that much more tdTomato+ HCs originated from Sox2+ SCs in Foxg1 cKD mice compared to the control mice. Moreover, the sphere-forming assay showed that Foxg1 cKD in Lgr5+ progenitors did not significantly change their sphere-forming ability. All these results suggest that Foxg1 cKD promotes HC regeneration and leads to large numbers of extra HCs probably by inducing direct trans-differentiation of SCs and progenitors to HCs. Real-time qPCR showed that cell cycle and Notch signaling pathways were significantly down-regulated in Foxg1 cKD mice cochlear SCs. Together, this study provides new evidence for the role of Foxg1 in regulating HC regeneration from SCs and progenitors in the neonatal mouse cochlea.
Collapse
Affiliation(s)
- Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Yuan Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Ying Dong
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Lingna Guo
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Zhong Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Buwei Shao
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Jieyu Qi
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Han Zhou
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Weijie Zhu
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Xiaoqian Yan
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Guodong Hong
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Liyan Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Xiaoli Zhang
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Chunjie Zhao
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China
| | - Xia Gao
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, 210096, China.
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China.
- Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 211189, China.
- Jiangsu Provincial Key Medical Discipline (Laboratory), Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, 210008, China.
- Key Laboratory of Hearing Medicine of NHFPC, ENT Institute and Otorhinolaryngology Department of Affiliated Eye and ENT Hospital, Shanghai Engineering Research Centre of Cochlear Implant, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China.
| |
Collapse
|
14
|
Li HJ, Ray SK, Pan N, Haigh J, Fritzsch B, Leiter AB. Intestinal Neurod1 expression impairs paneth cell differentiation and promotes enteroendocrine lineage specification. Sci Rep 2019; 9:19489. [PMID: 31862906 PMCID: PMC6925293 DOI: 10.1038/s41598-019-55292-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022] Open
Abstract
Transcription factor Neurod1 is required for enteroendocrine progenitor differentiation and maturation. Several earlier studies indicated that ectopic expression of Neurod1 converted non- neuronal cells into neurons. However, the functional consequence of ectopic Neurod1 expression has not been examined in the GI tract, and it is not known whether Neurod1 can similarly switch cell fates in the intestine. We generated a mouse line that would enable us to conditionally express Neurod1 in intestinal epithelial cells at different stages of differentiation. Forced expression of Neurod1 throughout intestinal epithelium increased the number of EECs as well as the expression of EE specific transcription factors and hormones. Furthermore, we observed a substantial reduction of Paneth cell marker expression, although the expressions of enterocyte-, tuft- and goblet-cell specific markers are largely not affected. Our earlier study indicated that Neurog3+ progenitor cells give rise to not only EECs but also Goblet and Paneth cells. Here we show that the conditional expression of Neurod1 restricts Neurog3+ progenitors to adopt Paneth cell fate, and promotes more pronounced EE cell differentiation, while such effects are not seen in more differentiated Neurod1+ cells. Together, our data suggest that forced expression of Neurod1 programs intestinal epithelial cells more towards an EE cell fate at the expense of the Paneth cell lineage and the effect ceases as cells mature to EE cells.
Collapse
Affiliation(s)
- Hui Joyce Li
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA, 01605, USA
| | - Subir K Ray
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA, 01605, USA
| | - Ning Pan
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
- Decibel Pharmaceutical, Boston, MA, USA
| | - Jody Haigh
- Department of Biomedical, Molecular Biology, Ghent University, Ghent, Belgium
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Andrew B Leiter
- Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA, 01605, USA.
| |
Collapse
|
15
|
Fritzsch B, Elliott KL. Auditory Nomenclature: Combining Name Recognition With Anatomical Description. Front Neuroanat 2018; 12:99. [PMID: 30532697 PMCID: PMC6265345 DOI: 10.3389/fnana.2018.00099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/05/2018] [Indexed: 01/20/2023] Open
Abstract
The inner ear and its two subsystems, the vestibular and the auditory system, exemplify how the identification of distinct cellular or anatomical elements ahead of elucidating their function, leads to a medley of anatomically defined and recognition oriented names that confused generations of students. Past attempts to clarify this unyielding nomenclature had incomplete success, as they could not yet generate an explanatory nomenclature. Building on these past efforts, we propose a somewhat revised nomenclature that keeps most of the past nomenclature as proposed and follows a simple rule: Anatomical and explanatory terms are combined followed, in brackets, by the name of the discoverer (see Table 1). For example, the "organ of Corti" will turn into the spiral auditory organ (of Corti). This revised nomenclature build as much as possible on existing terms that have explanatory value while keeping the recognition of discoverers alive to allow a transition for those used to the eponyms. Once implements, the proposed terminology should help future generations in learning the structure-function correlates of the ear more easily. To facilitate future understanding, leading genetic identifiers for a given structure have been added wherever possible.
Collapse
Affiliation(s)
- Bernd Fritzsch
- Department of Biology, The University of Iowa, Iowa City, IA, United States
| | | |
Collapse
|
16
|
Elliott KL, Fritzsch B, Duncan JS. Evolutionary and Developmental Biology Provide Insights Into the Regeneration of Organ of Corti Hair Cells. Front Cell Neurosci 2018; 12:252. [PMID: 30135646 PMCID: PMC6092489 DOI: 10.3389/fncel.2018.00252] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/23/2018] [Indexed: 01/19/2023] Open
Abstract
We review the evolution and development of organ of Corti hair cells with a focus on their molecular differences from vestibular hair cells. Such information is needed to therapeutically guide organ of Corti hair cell development in flat epithelia and generate the correct arrangement of different hair cell types, orientation of stereocilia, and the delayed loss of the kinocilium that are all essential for hearing, while avoiding driving hair cells toward a vestibular fate. Highlighting the differences from vestibular organs and defining what is known about the regulation of these differences will help focus future research directions toward successful restoration of an organ of Corti following long-term hair cell loss.
Collapse
Affiliation(s)
- Karen L Elliott
- Department of Biology, University of Iowa, Iowa City, IA, United States
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, United States
| | - Jeremy S Duncan
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
| |
Collapse
|
17
|
McPherson DR, Swalla BJ. High Time for Hair Cells: An Introduction to the Symposium on Sensory Hair Cells. Integr Comp Biol 2018; 58:276-281. [PMID: 30137315 DOI: 10.1093/icb/icy070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Sensory hair cells are highly specialized cells that form the basis for our senses of hearing, orientation to gravity, and perception of linear acceleration (head translation in space) and angular acceleration (head rotation). In many species of fish and aquatic amphibians, hair cells mediate perception of water movement through the lateral line system, and electroreceptors derived from hair cell precursors mediate electric field detection. In tunicates, cells of the mechanosensory coronal organ on the incurrent siphon meet the structural, functional, and developmental criteria to be described as hair cells, and they function to deflect large particles from entering the animal. The past two decades have witnessed significant breakthroughs in our understanding of hair cell biology and how their specialized structures influence their functions. This symposium combines the approaches of developmental biology, evolutionary biology, and physiology to share the gains of recent research in understanding hair cell function in different model systems. We brought together researchers working on sensory hair cells in organisms spanning the chordates in order to examine the depth and breadth of hair cell evolution. It is clear that these specialized cells serve a range of functions in different animals, due to evolutionary tinkering with a basic specialized cell type. This collection of papers will serve to mark the progress that has been made in this field and also stimulate the next wave of progress in this exciting field.
Collapse
Affiliation(s)
| | - Billie J Swalla
- Friday Harbor Laboratories, Friday Harbor, 620 University Road, WA 98250, USA
| |
Collapse
|