1
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Greenberg D, Rosenblum ND, Tonelli M. The multifaceted links between hearing loss and chronic kidney disease. Nat Rev Nephrol 2024; 20:295-312. [PMID: 38287134 DOI: 10.1038/s41581-024-00808-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2024] [Indexed: 01/31/2024]
Abstract
Hearing loss affects nearly 1.6 billion people and is the third-leading cause of disability worldwide. Chronic kidney disease (CKD) is also a common condition that is associated with adverse clinical outcomes and high health-care costs. From a developmental perspective, the structures responsible for hearing have a common morphogenetic origin with the kidney, and genetic abnormalities that cause familial forms of hearing loss can also lead to kidney disease. On a cellular level, normal kidney and cochlea function both depend on cilial activities at the apical surface, and kidney tubular cells and sensory epithelial cells of the inner ear use similar transport mechanisms to modify luminal fluid. The two organs also share the same collagen IV basement membrane network. Thus, strong developmental and physiological links exist between hearing and kidney function. These theoretical considerations are supported by epidemiological data demonstrating that CKD is associated with a graded and independent excess risk of sensorineural hearing loss. In addition to developmental and physiological links between kidney and cochlear function, hearing loss in patients with CKD may be driven by specific medications or treatments, including haemodialysis. The associations between these two common conditions are not commonly appreciated, yet have important implications for research and clinical practice.
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Affiliation(s)
- Dina Greenberg
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Norman D Rosenblum
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Marcello Tonelli
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
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2
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Qi J, Huang W, Lu Y, Yang X, Zhou Y, Chen T, Wang X, Yu Y, Sun JQ, Chai R. Stem Cell-Based Hair Cell Regeneration and Therapy in the Inner Ear. Neurosci Bull 2024; 40:113-126. [PMID: 37787875 PMCID: PMC10774470 DOI: 10.1007/s12264-023-01130-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: 12/28/2022] [Accepted: 06/01/2023] [Indexed: 10/04/2023] Open
Abstract
Hearing loss has become increasingly prevalent and causes considerable disability, thus gravely burdening the global economy. Irreversible loss of hair cells is a main cause of sensorineural hearing loss, and currently, the only relatively effective clinical treatments are limited to digital hearing equipment like cochlear implants and hearing aids, but these are of limited benefit in patients. It is therefore urgent to understand the mechanisms of damage repair in order to develop new neuroprotective strategies. At present, how to promote the regeneration of functional hair cells is a key scientific question in the field of hearing research. Multiple signaling pathways and transcriptional factors trigger the activation of hair cell progenitors and ensure the maturation of newborn hair cells, and in this article, we first review the principal mechanisms underlying hair cell reproduction. We then further discuss therapeutic strategies involving the co-regulation of multiple signaling pathways in order to induce effective functional hair cell regeneration after degeneration, and we summarize current achievements in hair cell regeneration. Lastly, we discuss potential future approaches, such as small molecule drugs and gene therapy, which might be applied for regenerating functional hair cells in the clinic.
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Affiliation(s)
- Jieyu Qi
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Wenjuan Huang
- Hospital of Southeast University, Nanjing, 210096, China
| | - Yicheng Lu
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xuehan Yang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yinyi Zhou
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Tian Chen
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xiaohan Wang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yafeng Yu
- First Affiliated Hospital of Soochow University, Suzhou, 215006, China.
| | - Jia-Qiang 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, 230001, China.
| | - Renjie Chai
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China.
- Department of Otolaryngology Head and Neck Surgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610072, China.
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
- Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, 100101, China.
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3
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Smith-Cortinez N, Hendriksen FGJ, Ramekers D, Stokroos RJ, Versnel H, Straatman LV. Long-term survival of LGR5 expressing supporting cells after severe ototoxic trauma in the adult mouse cochlea. Front Cell Neurosci 2023; 17:1236894. [PMID: 37692553 PMCID: PMC10483136 DOI: 10.3389/fncel.2023.1236894] [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: 06/08/2023] [Accepted: 08/07/2023] [Indexed: 09/12/2023] Open
Abstract
Introduction The leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) is a tissue resident stem cell marker, which it is expressed in supporting cells (SCs) in the organ of Corti in the mammalian inner ear. These LGR5+ SCs can be used as an endogenous source of progenitor cells for regeneration of hair cells (HCs) to treat hearing loss and deafness. We have recently reported that LGR5+ SCs survive 1 week after ototoxic trauma. Here, we evaluated Lgr5 expression in the adult cochlea and long-term survival of LGR5+ SCs following severe hearing loss. Methods Lgr5GFP transgenic mice and wild type mice aged postnatal day 30 (P30) and P200 were used. P30 animals were deafened with a single dose of furosemide and kanamycin. Seven and 28 days after deafening, auditory brainstem responses (ABRs) were recorded. Cochleas were harvested to characterize mature HCs and LGR5+ SCs by immunofluorescence microscopy and quantitative reverse transcription PCR (q-RT-PCR). Results There were no significant age-related changes in Lgr5 expression when comparing normal-hearing (NH) mice aged P200 with P30. Seven and 28 days after ototoxic trauma, there was severe outer HC loss and LGR5 was expressed in the third row of Deiters' cells and in inner pillar cells. Seven days after induction of ototoxic trauma there was an up-regulation of the mRNA expression of Lgr5 compared to the NH condition; 28 days after ototoxic trauma Lgr5 expression was similar to NH levels. Discussion The presence of LGR5+ SCs in the adult mouse cochlea, which persists after severe HC loss, suggests potential regenerative capacity of endogenous cochlear progenitor cells in adulthood. To our knowledge, this is the first study showing not only long-term survival of LGR5+ SCs in the normal and ototoxically damaged cochlea, but also increased Lgr5 expression in the adult mouse cochlea after deafening, suggesting long-term availability of potential target cells for future regenerative therapies.
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Affiliation(s)
- Natalia Smith-Cortinez
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
- UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Ferry G. J. Hendriksen
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Dyan Ramekers
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
- UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Robert J. Stokroos
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
- UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Huib Versnel
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
- UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Louise V. Straatman
- Department of Otorhinolaryngology-Head and Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
- UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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4
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Blinkiewicz PV, Long MR, Stoner ZA, Ketchum EM, Sheltz-Kempf SN, Duncan JS. Gata3 is required in late proneurosensory development for proper sensory cell formation and organization. Sci Rep 2023; 13:12573. [PMID: 37537240 PMCID: PMC10400699 DOI: 10.1038/s41598-023-39707-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/29/2023] [Indexed: 08/05/2023] Open
Abstract
It has previously been shown that the zinc-finger transcription factor Gata3 has dynamic expression within the inner ear throughout embryonic development and is essential for cochlear neurosensory development. However, the temporal window for which Gata3 is required for proper formation of the cochlear neurosensory epithelia remains unclear. To investigate the role of Gata3 in cochlear neurosensory development in the late prosensory stages, we used the Sox2-creERT2 mouse line to target and conditionally delete Gata3 at E11.5, a timepoint before cells have fully committed to a neurosensory fate. While the inner ears of Sox2-creERT2: Gata3 f/f mice appear normal with no gross structural defects, the sensory cells in the organ of Corti are partially lost and disorganized in an increasing severity from base to apex. Additionally, spiral ganglion neurons display aberrant peripheral projections, including increased distances between radial bundles and disorganization upon reaching the organ of Corti. Furthermore, heterozygous Sox2-creERT2: Gata3 f/+ mice show a reduced aberrant phenotype in comparison to the homozygous mutant, supporting the hypothesis that Gata3 is not only required for proper formation at the later proneurosensory stage, but also that a specific expression level of Gata3 is required. Therefore, this study provides evidence that Gata3 plays a time-sensitive and dose-dependent role in the development of sensory and neuronal cells in late proneurosensory stages.
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Affiliation(s)
- Paige V Blinkiewicz
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | - Makayla R Long
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | - Zachary A Stoner
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA.
- Section On Sensory Cell Regeneration and Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Elizabeth M Ketchum
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | | | - Jeremy S Duncan
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA.
- Department of Biomedical Sciences, Western Michigan School of Medicine, Kalamazoo, MI, USA.
- Department of Neurology, University of Minnesota, Minneapolis, MN, USA.
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5
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Smith-Cortinez N, Tan AK, Stokroos RJ, Versnel H, Straatman LV. Regeneration of Hair Cells from Endogenous Otic Progenitors in the Adult Mammalian Cochlea: Understanding Its Origins and Future Directions. Int J Mol Sci 2023; 24:ijms24097840. [PMID: 37175547 PMCID: PMC10177935 DOI: 10.3390/ijms24097840] [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: 03/13/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023] Open
Abstract
Sensorineural hearing loss is caused by damage to sensory hair cells and/or spiral ganglion neurons. In non-mammalian species, hair cell regeneration after damage is observed, even in adulthood. Although the neonatal mammalian cochlea carries regenerative potential, the adult cochlea cannot regenerate lost hair cells. The survival of supporting cells with regenerative potential after cochlear trauma in adults is promising for promoting hair cell regeneration through therapeutic approaches. Targeting these cells by manipulating key signaling pathways that control mammalian cochlear development and non-mammalian hair cell regeneration could lead to regeneration of hair cells in the mammalian cochlea. This review discusses the pathways involved in the development of the cochlea and the impact that trauma has on the regenerative capacity of the endogenous progenitor cells. Furthermore, it discusses the effects of manipulating key signaling pathways targeting supporting cells with progenitor potential to promote hair cell regeneration and translates these findings to the human situation. To improve hearing recovery after hearing loss in adults, we propose a combined approach targeting (1) the endogenous progenitor cells by manipulating signaling pathways (Wnt, Notch, Shh, FGF and BMP/TGFβ signaling pathways), (2) by manipulating epigenetic control, and (3) by applying neurotrophic treatments to promote reinnervation.
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Affiliation(s)
- Natalia Smith-Cortinez
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - A Katherine Tan
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Robert J Stokroos
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Huib Versnel
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
| | - Louise V Straatman
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- UMC Utrecht Brain Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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6
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Blinkiewicz PV, Long MR, Stoner ZA, Ketchum EM, Sheltz-Kempf SN, Duncan JS. Gata3 is Required in Late Proneurosensory Development for Proper Sensory Cell Formation and Organization. RESEARCH SQUARE 2023:rs.3.rs-2747944. [PMID: 37090645 PMCID: PMC10120746 DOI: 10.21203/rs.3.rs-2747944/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
It has been previously shown that zinc-finger transcription factor Gata3 has dynamic expression within the inner ear throughout embryonic development and is essential for cochlear neurosensory development. However, the temporal window to which Gata3 is required for the formation of the cochlear neurosensory epithelia remains unclear. To investigate the role of Gata3 on cochlear neurosensory development in the late prosensory stages, we used the Sox2-cre ERT2 mouse line to target and conditionally delete Gata3 at E11.5 before the cells have fully committed to a neurosensory fate. While the inner ears of Sox2-cre ERT2 : Gata3 f/f mice appear morphologically normal, the sensory cells in the organ of Corti are partially lost and disorganized in a basal to apical gradient with the apex demonstrating the more severe phenotype. Additionally, spiral ganglion neurons display aberrant peripheral projections, such as increased distances between radial bundles and disorganization upon reaching the organ of Corti. Furthermore, heterozygous Sox2-cre ERT2 : Gata3 f/+ mice show a reduced phenotype in comparison to the homozygous mutant, supporting the concept that Gata3 is not only required for proper formation at the later proneurosensory stage, but also that a specific level of Gata3 is required. Therefore, our studies confirm that Gata3 plays a time-sensitive and dose-dependent role in the development of sensory cells in the late proneurosensory stages.
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7
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Sufu- and Spop-mediated regulation of Gli2 is essential for the control of mammalian cochlear hair cell differentiation. Proc Natl Acad Sci U S A 2022; 119:e2206571119. [PMID: 36252002 PMCID: PMC9618052 DOI: 10.1073/pnas.2206571119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Development of mammalian auditory epithelium, the organ of Corti, requires precise control of both cell cycle withdrawal and differentiation. Sensory progenitors (prosensory cells) in the cochlear apex exit the cell cycle first but differentiate last. Sonic hedgehog (Shh) signaling is required for the spatiotemporal regulation of prosensory cell differentiation, but the underlying mechanisms remain unclear. Here, we show that suppressor of fused (Sufu), a negative regulator of Shh signaling, is essential for controlling the timing and progression of hair cell (HC) differentiation. Removal of Sufu leads to abnormal Atoh1 expression and a severe delay of HC differentiation due to elevated Gli2 mRNA expression. Later in development, HC differentiation defects are restored in the Sufu mutant by the action of speckle-type PDZ protein (Spop), which promotes Gli2 protein degradation. Deletion of both Sufu and Spop results in robust Gli2 activation, exacerbating HC differentiation defects. We further demonstrate that Gli2 inhibits HC differentiation through maintaining the progenitor state of Sox2+ prosensory cells. Along the basal-apical axis of the developing cochlea, the Sox2 expression level is higher in the progenitor cells than in differentiating cells and is down-regulated from base to apex as differentiation proceeds. The dynamic spatiotemporal change of Sox2 expression levels is controlled by Shh signaling through Gli2. Together, our results reveal key functions of Gli2 in sustaining the progenitor state, thereby preventing HC differentiation and in turn governing the basal-apical progression of HC differentiation in the cochlea.
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8
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Chen J, Gao D, Sun L, Yang J. Kölliker’s organ-supporting cells and cochlear auditory development. Front Mol Neurosci 2022; 15:1031989. [PMID: 36304996 PMCID: PMC9592740 DOI: 10.3389/fnmol.2022.1031989] [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: 08/30/2022] [Accepted: 09/23/2022] [Indexed: 11/21/2022] Open
Abstract
The Kölliker’s organ is a transient cellular cluster structure in the development of the mammalian cochlea. It gradually degenerates from embryonic columnar cells to cuboidal cells in the internal sulcus at postnatal day 12 (P12)–P14, with the cochlea maturing when the degeneration of supporting cells in the Kölliker’s organ is complete, which is distinct from humans because it disappears at birth already. The supporting cells in the Kölliker’s organ play a key role during this critical period of auditory development. Spontaneous release of ATP induces an increase in intracellular Ca2+ levels in inner hair cells in a paracrine form via intercellular gap junction protein hemichannels. The Ca2+ further induces the release of the neurotransmitter glutamate from the synaptic vesicles of the inner hair cells, which subsequently excite afferent nerve fibers. In this way, the supporting cells in the Kölliker’s organ transmit temporal and spatial information relevant to cochlear development to the hair cells, promoting fine-tuned connections at the synapses in the auditory pathway, thus facilitating cochlear maturation and auditory acquisition. The Kölliker’s organ plays a crucial role in such a scenario. In this article, we review the morphological changes, biological functions, degeneration, possible trans-differentiation of cochlear hair cells, and potential molecular mechanisms of supporting cells in the Kölliker’s organ during the auditory development in mammals, as well as future research perspectives.
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Affiliation(s)
- Jianyong Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Dekun Gao
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Lianhua Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- *Correspondence: Lianhua Sun Jun Yang
| | - Jun Yang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- *Correspondence: Lianhua Sun Jun Yang
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9
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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.
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10
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Chen J, Gao D, Chen J, Hou S, He B, Li Y, Li S, Zhang F, Sun X, Jin Y, Sun L, Yang J. Pseudo-Temporal Analysis of Single-Cell RNA Sequencing Reveals Trans-Differentiation Potential of Greater Epithelial Ridge Cells Into Hair Cells During Postnatal Development of Cochlea in Rats. Front Mol Neurosci 2022; 15:832813. [PMID: 35370544 PMCID: PMC8966675 DOI: 10.3389/fnmol.2022.832813] [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: 12/10/2021] [Accepted: 02/08/2022] [Indexed: 11/23/2022] Open
Abstract
The hair cells of the cochlea play a decisive role in the process of hearing damage and recovery, yet knowledge of their regeneration process is still limited. Greater epithelial ridge (GER) cells, a type of cell present during cochlear development that has the characteristics of a precursor sensory cell, disappear at the time of maturation of hearing development. Its development and evolution remain mysterious for many years. Here, we performed single-cell RNA sequencing to profile the gene expression landscapes of rats’ cochlear basal membrane from P1, P7, and P14 and identified eight major subtypes of GER cells. Furthermore, single-cell trajectory analysis for GER cells and hair cells indicated that among the different subtypes of GER, four subtypes had transient cell proliferation after birth and could transdifferentiate into inner and outer hair cells, and two of them mainly transdifferentiated into inner hair cells. The other two subtypes eventually transdifferentiate into outer hair cells. Our study lays the groundwork for elucidating the mechanisms of the key regulatory genes and signaling pathways in the trans-differentiation of GER cell subtypes into hair cells and provides potential clues to understand hair cell regeneration.
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Affiliation(s)
- Jianyong Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Dekun Gao
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Junmin Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Shule Hou
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Baihui He
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Yue Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Shuna Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Fan Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Xiayu Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Yulian Jin
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- *Correspondence: Yulian Jin,
| | - Lianhua Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- Lianhua Sun,
| | - Jun Yang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- Jun Yang,
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11
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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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12
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Rai V, Tu S, Frank JR, Zuo J. Molecular Pathways Modulating Sensory Hair Cell Regeneration in Adult Mammalian Cochleae: Progress and Perspectives. Int J Mol Sci 2021; 23:ijms23010066. [PMID: 35008497 PMCID: PMC8745006 DOI: 10.3390/ijms23010066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 12/30/2022] Open
Abstract
Noise-induced, drug-related, and age-related disabling hearing loss is a major public health problem and affect approximately 466 million people worldwide. In non-mammalian vertebrates, the death of sensory hair cells (HCs) induces the proliferation and transdifferentiation of adjacent supporting cells into new HCs; however, this capacity is lost in juvenile and adult mammalian cochleae leading to permanent hearing loss. At present, cochlear implants and hearing devices are the only available treatments and can help patients to a certain extent; however, no biological approach or FDA-approved drug is effective to treat disabling hearing loss and restore hearing. Recently, regeneration of mammalian cochlear HCs by modulating molecular pathways or transcription factors has offered some promising results, although the immaturity of the regenerated HCs remains the biggest concern. Furthermore, most of the research done is in neonates and not in adults. This review focuses on critically summarizing the studies done in adult mammalian cochleae and discusses various strategies to elucidate novel transcription factors for better therapeutics.
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Affiliation(s)
| | | | | | - Jian Zuo
- Correspondence: ; Tel.: +1-(402)-280-2916
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13
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Purwar N, Tiwari P, Mathur N, Sharma H, Sahlot R, Garg U, Sharma B, Saxena A, Mathur SK. Higher CNV Frequencies in Chromosome 14 of Girls With Turner Syndrome Phenotype. J Clin Endocrinol Metab 2021; 106:e4935-e4955. [PMID: 34333639 DOI: 10.1210/clinem/dgab572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Precise genotype-phenotype correlations in Turner syndrome (TS) have not yet been deciphered. The chromosomal basis of the clinical TS phenotype in the absence of X chromosome aberrations on conventional karyotyping remains more and less unexplored. OBJECTIVE To elucidate the high-resolution chromosomal picture and analyze the genotype-phenotype associations in girls with clinical phenotype of TS by chromosomal microarray. DESIGN AND PATIENTS Cross sectional observational study conducted between October 2018 and January 2020 on 47 girls presenting the clinical TS phenotype and fulfilling the criteria for chromosomal analysis. SETTING Outpatient department at Department of Endocrinology and the Molecular Research Lab at tertiary care teaching institution. RESULTS The copy number variation (CNV) polymorphs were more frequent on autosomes than X chromosomes, and they were detected in 89.3%, 61.7%, and 92.8% of patients, respectively, on chromosome 14 or X or both. A total 445 and 64 CNV polymorphs were discovered on chromosome X and 14, respectively. The latter exhibited either gain at 14q32.33, loss at 14q11.2, or both. Karyotype was available for 27 patients; 55.6% of cases displayed X chromosome abnormalities while 44.4% cases had a normal karyotype. Functional interactomes of the genes that were present in chromosome 14 CNVs and those known to be associated with TS showed an overlap of 67% and enriched various development-related cellular pathways underlying TS phenotype. CONCLUSIONS On high-resolution karyotype analysis, clinical phenotype of TS can be associated with CNV defects in autosomes, specifically chromosome 14 or X chromosome or both. The syndrome of chromosome 14 CNV defects with and without X-chromosomal defects clinically mimics TS and shares a common genomic network that deserves further investigations.
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Affiliation(s)
- Naincy Purwar
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
| | - Pradeep Tiwari
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
- Department of Chemistry, School of Basic Sciences, Manipal University Jaipur, Jaipur, India
| | - Nitish Mathur
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
| | - Himanshu Sharma
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
| | - Rahul Sahlot
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
| | - Umesh Garg
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
| | - Balram Sharma
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
| | - Aditya Saxena
- Department of Computer Engineering & Applications, Institute of Engineering & Technology, GLA University, Mathura, India
| | - Sandeep K Mathur
- Department of Endocrinology, Sawai Man Singh Medical College and Hospital, Jaipur 302004, India
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14
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Riley BB. Comparative assessment of Fgf's diverse roles in inner ear development: A zebrafish perspective. Dev Dyn 2021; 250:1524-1551. [PMID: 33830554 DOI: 10.1002/dvdy.343] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 01/21/2023] Open
Abstract
Progress in understanding mechanisms of inner ear development has been remarkably rapid in recent years. The research community has benefited from the availability of several diverse model organisms, including zebrafish, chick, and mouse. The complexity of the inner ear has proven to be a challenge, and the complexity of the mammalian cochlea in particular has been the subject of intense scrutiny. Zebrafish lack a cochlea and exhibit a number of other differences from amniote species, hence they are sometimes seen as less relevant for inner ear studies. However, accumulating evidence shows that underlying cellular and molecular mechanisms are often highly conserved. As a case in point, consideration of the diverse functions of Fgf and its downstream effectors reveals many similarities between vertebrate species, allowing meaningful comparisons the can benefit the entire research community. In this review, I will discuss mechanisms by which Fgf controls key events in early otic development in zebrafish and provide direct comparisons with chick and mouse.
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Affiliation(s)
- Bruce B Riley
- Biology Department, Texas A&M University, College Station, Texas, USA
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15
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The crosstalk between the Notch, Wnt, and SHH signaling pathways in regulating the proliferation and regeneration of sensory progenitor cells in the mouse cochlea. Cell Tissue Res 2021; 386:281-296. [PMID: 34223978 PMCID: PMC8557196 DOI: 10.1007/s00441-021-03493-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/21/2021] [Indexed: 12/04/2022]
Abstract
Sensory hair cells (HCs) are highly susceptible to damage by noise, ototoxic drugs, and aging. Although HCs cannot be spontaneously regenerated in adult mammals, previous studies have shown that signaling pathways are involved in HC regeneration in the damaged mouse cochlea. Here, we used a Notch antagonist (DAPT), a Wnt agonist (QS11), and recombinant Sonic hedgehog (SHH) protein to investigate their concerted actions underlying HC regeneration in the mouse cochlea after neomycin-induced damage both in vivo and in vitro. With DAPT, the numbers of HCs increased, and supporting cell (SC) proliferation was seen in both the intact and damaged cochlear sensory epithelia, while these numbers were unchanged in the presence of QS11. When simultaneously treated with DAPT and QS11, the number of HCs increased dramatically, and much greater SC proliferation was seen in the cochlear epithelium. In transgenic mice with both Notch1 conditional knockout and β-catenin over-expression, cochlear SC proliferation and HC regeneration were more obvious than in either Notch1 knockout or β-catenin over-expressing mice separately. When cochleae were treated with DAPT, QS11, and SHH together, SC proliferation was even greater, and this proliferation was seen in both the HC region and the greater epithelial ridge. High-throughput RNA sequencing was used to identify the differentially expressed genes between all groups, and the results showed that the SHH and Wnt signaling pathways are involved in SC proliferation. Our study suggests that co-regulation of the Notch, Wnt, and SHH signaling pathways promotes extensive cell proliferation and regeneration in the mouse cochlea.
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16
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Stabenau KA, Zimmermann MT, Mathison A, Zeighami A, Samuels TL, Chun RH, Papsin BC, McCormick ME, Johnston N, Kerschner JE. RNA Sequencing and Pathways Analyses of Middle Ear Epithelia From Patients With Otitis Media. Laryngoscope 2021; 131:2590-2597. [PMID: 33844317 DOI: 10.1002/lary.29551] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/04/2021] [Accepted: 03/23/2021] [Indexed: 01/24/2023]
Abstract
OBJECTIVES Otitis media (OM) is the most common pediatric diagnosis in the United States. However, our understanding of the molecular pathogenesis of OM remains relatively poor. Investigation of molecular pathways involved in OM may improve the understanding of this disease process and elucidate novel therapeutic targets. In this study, RNA sequencing (RNA-Seq) was used to discern cellular changes associated with OME compared to healthy middle ear epithelium (MEE). STUDY DESIGN Ex vivo case-control translational. METHODS Middle ear epithelia was collected from five pediatric patients diagnosed with OME undergoing tympanostomy tube placement and five otherwise healthy pediatric patients undergoing cochlear implantation. Specimens underwent RNA-Seq and pathways analyses. RESULTS A total of 1,292 genes exhibited differential expression in MEE from OME patients compared to controls including genes involved in inflammation, immune response to bacterial OM pathogens, mucociliary clearance, regulation of proliferation and transformation, and auditory cell differentiation. Top networks identified in OME were organismal injury and abnormalities, cell morphology, and auditory disease. Top Ingenuity canonical pathways identified were axonal guidance signaling, which contains genes associated with auditory development and disease and nicotine degradation II and III pathways. Associated upstream regulators included β-estradiol, dexamethasone, and G-protein-coupled estrogen receptor-1 (GPER1), which are associated with otoprotection or inflammation during insult. CONCLUSIONS RNA-Seq demonstrates differential gene expression in MEE from patients with OME compared to healthy controls with important implications for infection susceptibility, hearing loss, and a role for tobacco exposure in the development and/or severity of OME in pediatric patients. LEVEL OF EVIDENCE 4 Laryngoscope, 2021.
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Affiliation(s)
- Kaleigh A Stabenau
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Michael T Zimmermann
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A.,Clinical and Translational Science Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Angela Mathison
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Atefeh Zeighami
- Bioinformatics Research and Development Laboratory, Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Tina L Samuels
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Robert H Chun
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Blake C Papsin
- Archie's Cochlear Implant Laboratory, Department of Otolaryngology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Michael E McCormick
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Nikki Johnston
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A.,Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
| | - Joseph E Kerschner
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, U.S.A
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17
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Moon KH, Ma JH, Min H, Koo H, Kim H, Ko HW, Bok J. Dysregulation of sonic hedgehog signaling causes hearing loss in ciliopathy mouse models. eLife 2020; 9:56551. [PMID: 33382037 PMCID: PMC7806262 DOI: 10.7554/elife.56551] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 12/31/2020] [Indexed: 12/11/2022] Open
Abstract
Defective primary cilia cause a range of diseases known as ciliopathies, including hearing loss. The etiology of hearing loss in ciliopathies, however, remains unclear. We analyzed cochleae from three ciliopathy mouse models exhibiting different ciliogenesis defects: Intraflagellar transport 88 (Ift88), Tbc1d32 (a.k.a. bromi), and Cilk1 (a.k.a. Ick) mutants. These mutants showed multiple developmental defects including shortened cochlear duct and abnormal apical patterning of the organ of Corti. Although ciliogenic defects in cochlear hair cells such as misalignment of the kinocilium are often associated with the planar cell polarity pathway, our results showed that inner ear defects in these mutants are primarily due to loss of sonic hedgehog signaling. Furthermore, an inner ear-specific deletion of Cilk1 elicits low-frequency hearing loss attributable to cellular changes in apical cochlear identity that is dedicated to low-frequency sound detection. This type of hearing loss may account for hearing deficits in some patients with ciliopathies.
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Affiliation(s)
- Kyeong-Hye Moon
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 PLUS project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Ji-Hyun Ma
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hyehyun Min
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Heiyeun Koo
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 PLUS project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - HongKyung Kim
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hyuk Wan Ko
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Jinwoong Bok
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea.,BK21 PLUS project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea
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18
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van der Valk WH, Steinhart MR, Zhang J, Koehler KR. Building inner ears: recent advances and future challenges for in vitro organoid systems. Cell Death Differ 2020; 28:24-34. [PMID: 33318601 PMCID: PMC7853146 DOI: 10.1038/s41418-020-00678-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
While inner ear disorders are common, our ability to intervene and recover their sensory function is limited. In vitro models of the inner ear, like the organoid system, could aid in identifying new regenerative drugs and gene therapies. Here, we provide a perspective on the status of in vitro inner ear models and guidance on how to improve their applicability in translational research. We highlight the generation of inner ear cell types from pluripotent stem cells as a particularly promising focus of research. Several exciting recent studies have shown how the developmental signaling cues of embryonic and fetal development can be mimicked to differentiate stem cells into “inner ear organoids” containing otic progenitor cells, hair cells, and neurons. However, current differentiation protocols and our knowledge of embryonic and fetal inner ear development in general, have a bias toward the sensory epithelia of the inner ear. We propose that a more holistic view is needed to better model the inner ear in vitro. Moving forward, attention should be made to the broader diversity of neuroglial and mesenchymal cell types of the inner ear, and how they interact in space or time during development. With improved control of epithelial, neuroglial, and mesenchymal cell fate specification, inner ear organoids would have the ability to truly recapitulate neurosensory function and dysfunction. We conclude by discussing how single-cell atlases of the developing inner ear and technical innovations will be critical tools to advance inner ear organoid platforms for future pre-clinical applications.
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Affiliation(s)
- Wouter H van der Valk
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, Netherlands.,Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Matthew R Steinhart
- Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA.,Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.,Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jingyuan Zhang
- Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA.,Department of Plastic and Oral Surgery, Boston Children's Hospital, Boston, MA, 02115, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA.,Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, 02115, USA
| | - Karl R Koehler
- Department of Otolaryngology, Boston Children's Hospital, Boston, MA, 02115, USA. .,Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA. .,Department of Plastic and Oral Surgery, Boston Children's Hospital, Boston, MA, 02115, USA. .,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA. .,Department of Otolaryngology-Head and Neck Surgery, Harvard Medical School, Boston, MA, 02115, USA.
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19
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White PM. Perspectives on Human Hearing Loss, Cochlear Regeneration, and the Potential for Hearing Restoration Therapies. Brain Sci 2020; 10:E756. [PMID: 33092183 PMCID: PMC7589617 DOI: 10.3390/brainsci10100756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/13/2020] [Accepted: 10/16/2020] [Indexed: 12/23/2022] Open
Abstract
Most adults who acquire hearing loss find it to be a disability that is poorly corrected by current prosthetics. This gap drives current research in cochlear mechanosensory hair cell regeneration and in hearing restoration. Birds and fish can spontaneously regenerate lost hair cells through a process that has become better defined in the last few years. Findings from these studies have informed new research on hair cell regeneration in the mammalian cochlea. Hair cell regeneration is one part of the greater problem of hearing restoration, as hearing loss can stem from a myriad of causes. This review discusses these issues and recent findings, and places them in the greater social context of need and community.
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Affiliation(s)
- Patricia M White
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, USA
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20
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Kannan-Sundhari A, Abad C, Maloof ME, Ayad NG, Young JI, Liu XZ, Walz K. Bromodomain Protein BRD4 Is Essential for Hair Cell Function and Survival. Front Cell Dev Biol 2020; 8:576654. [PMID: 33015071 PMCID: PMC7509448 DOI: 10.3389/fcell.2020.576654] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
Hair cells (HCs) play crucial roles in perceiving sound, acceleration, and fluid motion. The tonotopic architecture of the sensory epithelium recognizes mechanical stimuli and convert them into electrical signals. The expression and regulation of the genes in the inner ear is very important to keep the sensory organ functional. Our study is the first to investigate the role of the epigenetic reader Brd4 in the mouse inner ear. We demonstrate that HC specific deletion of Brd4 in vivo in the mouse inner ear is sufficient to cause profound hearing loss (HL), degeneration of stereocilia, nerve fibers and HC loss postnatally in mouse; suggesting an important role in hearing function and maintenance.
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Affiliation(s)
- Abhiraami Kannan-Sundhari
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, FL, United States.,The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, United States
| | - Clemer Abad
- John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, United States
| | - Marie E Maloof
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Nagi G Ayad
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Juan I Young
- The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, United States.,John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, United States
| | - Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, FL, United States.,The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, United States.,John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, United States
| | - Katherina Walz
- The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Miami, FL, United States.,John P. Hussman Institute for Human Genomics, University of Miami, Miami, FL, United States
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21
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Abstract
The cochlea, a coiled structure located in the ventral region of the inner ear, acts as the primary structure for the perception of sound. Along the length of the cochlear spiral is the organ of Corti, a highly derived and rigorously patterned sensory epithelium that acts to convert auditory stimuli into neural impulses. The development of the organ of Corti requires a series of inductive events that specify unique cellular characteristics and axial identities along its three major axes. Here, we review recent studies of the cellular and molecular processes regulating several aspects of cochlear development, such as axial patterning, cochlear outgrowth and cellular differentiation. We highlight how the precise coordination of multiple signaling pathways is required for the successful formation of a complete organ of Corti.
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Affiliation(s)
- Elizabeth Carroll Driver
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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22
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Bozal-Basterra L, Gonzalez-Santamarta M, Muratore V, Bermejo-Arteagabeitia A, Da Fonseca C, Barroso-Gomila O, Azkargorta M, Iloro I, Pampliega O, Andrade R, Martín-Martín N, Branon TC, Ting AY, Rodríguez JA, Carracedo A, Elortza F, Sutherland JD, Barrio R. LUZP1, a novel regulator of primary cilia and the actin cytoskeleton, is a contributing factor in Townes-Brocks Syndrome. eLife 2020; 9:e55957. [PMID: 32553112 PMCID: PMC7363444 DOI: 10.7554/elife.55957] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/18/2020] [Indexed: 12/20/2022] Open
Abstract
Primary cilia are sensory organelles crucial for cell signaling during development and organ homeostasis. Cilia arise from centrosomes and their formation and function is governed by numerous factors. Through our studies on Townes-Brocks Syndrome (TBS), a rare disease linked to abnormal cilia formation in human fibroblasts, we uncovered the leucine-zipper protein LUZP1 as an interactor of truncated SALL1, a dominantly-acting protein causing the disease. Using TurboID proximity labeling and pulldowns, we show that LUZP1 associates with factors linked to centrosome and actin filaments. Here, we show that LUZP1 is a cilia regulator. It localizes around the centrioles and to actin cytoskeleton. Loss of LUZP1 reduces F-actin levels, facilitates ciliogenesis and alters Sonic Hedgehog signaling, pointing to a key role in cytoskeleton-cilia interdependency. Truncated SALL1 increases the ubiquitin proteasome-mediated degradation of LUZP1. Together with other factors, alterations in LUZP1 may be contributing to TBS etiology.
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Affiliation(s)
- Laura Bozal-Basterra
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - María Gonzalez-Santamarta
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Veronica Muratore
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Aitor Bermejo-Arteagabeitia
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Carolina Da Fonseca
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Orhi Barroso-Gomila
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Mikel Azkargorta
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
- CIBERehd, Instituto de Salud Carlos IIIMadridSpain
- ProteoRed-ISCIII, Instituto de Salud Carlos IIIMadridSpain
| | - Ibon Iloro
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
- CIBERehd, Instituto de Salud Carlos IIIMadridSpain
- ProteoRed-ISCIII, Instituto de Salud Carlos IIIMadridSpain
| | - Olatz Pampliega
- Department of Neurosciences, University of the Basque Country, Achucarro Basque Center for Neuroscience-UPV/EHULeioaSpain
| | - Ricardo Andrade
- Analytical & High Resolution Biomedical Microscopy Core Facility, University of the Basque Country (UPV/EHU)LeioaSpain
| | - Natalia Martín-Martín
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Tess C Branon
- Department of Chemistry, Massachusetts Institute of TechnologyCambridgeUnited States
- Departments of Genetics, Chemistry and Biology, Stanford UniversityStanfordUnited States
| | - Alice Y Ting
- Department of Chemistry, Massachusetts Institute of TechnologyCambridgeUnited States
- Departments of Genetics, Chemistry and Biology, Stanford UniversityStanfordUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Jose A Rodríguez
- Department of Genetics, Physical Anthropology and Animal Physiology, University of the Basque Country (UPV/EHU)LeioaSpain
| | - Arkaitz Carracedo
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
- CIBERONC, Instituto de Salud Carlos IIIMadridSpain
- Ikerbasque, Basque Foundation for ScienceBilbaoSpain
- Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU)BilbaoSpain
| | - Felix Elortza
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
- CIBERehd, Instituto de Salud Carlos IIIMadridSpain
- ProteoRed-ISCIII, Instituto de Salud Carlos IIIMadridSpain
| | - James D Sutherland
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
| | - Rosa Barrio
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology ParkDerioSpain
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Zhang S, Qiang R, Dong Y, Zhang Y, Chen Y, Zhou H, Gao X, Chai R. Hair cell regeneration from inner ear progenitors in the mammalian cochlea. AMERICAN JOURNAL OF STEM CELLS 2020; 9:25-35. [PMID: 32699655 PMCID: PMC7364385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
Cochlear hair cells (HCs) are the mechanoreceptors of the auditory system, and because these cells cannot be spontaneously regenerated in adult mammals, hearing loss due to HC damage is permanent. However, cochleae of neonatal mice harbor some progenitor cells that retain limited ability to give rise to new HCs in vivo. Here we review the regulatory factors, signaling pathways, and epigenetic factors that have been reported to play roles in HC regeneration in the neonatal mammalian cochlea.
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Affiliation(s)
- Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Ruiying Qiang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Ying Dong
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Yuan Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
| | - Yin Chen
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
| | - Han Zhou
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
| | - Xia Gao
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast UniversityNanjing 210096, China
- Co-Innovation Center of Neuroregeneration, Nantong UniversityNantong 226001, China
- Institute for Stem Cell and Regeneration, Chinese Academy of ScienceBeijing, China
- Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast UniversityNanjing 211189, China
- Department of Otolaryngology Head and Neck Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, Jiangsu Provincial Key Medical Discipline (Laboratory)Nanjing 210008, China
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Transcriptome Analysis of Deafness: Intracellular Signal Transduction Signaling Pathways Regulate Neuroplastic Changes in the Auditory Cortex. Otol Neurotol 2020; 41:986-996. [PMID: 32501934 DOI: 10.1097/mao.0000000000002691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
HYPOTHESIS AND BACKGROUND Hearing loss leads to synaptic changes in auditory neurons and their networks, and functions as a consequence of the interplay between genes and proteins. However, cellular and molecular mechanisms leading to deafness-induced plasticity in the auditory cortex (AC) remain unclear. Here, we examined the changes in gene expression and key signaling pathways that regulate differentially expressed genes (DEGs) in the AC following auditory deafferentation using RNA-sequencing (RNA-Seq) analysis. METHODS Cochlear ablation-induced bilaterally deafened Sprague-Dawley rats were maintained for 12 weeks and their ACs were harvested. RNA-seq analysis was performed on each sample to identify which genes were expressed. This information was then used for comparative analysis of DEGs between samples. The statistical significance of DEGs was determined by fold change (|FC| > 1.5) and independent t test (p < 0.05). RESULTS RNA-seq analysis identified 72 DEGs, of which 19 were upregulated and 53 were down-regulated after bilateral deafening in the ACs. Gene ontology (GO) analysis revealed the potential involvement of mitogen-activated protein kinase, tumor necrosis factor, and cyclic adenosine 3',5'-monophosphate (e.g., Bdnf, Gli1, and c-Fos) signaling pathways in regulating changes in the expression of the genes listed herein. The DEGs of interest-including c-Fos, Arc, Ntf3, and Gli1-from the RNA-seq analysis were consistent with result of quantitative reverse transcriptase polymerase chain reaction. CONCLUSION RNA-seq analysis revealed that auditory deprivation in adult rats elicited changes in gene expression, transcription factor levels, and their complex interaction at specific gene promoters in the AC. Particularly, activation of intracellular signal transduction signaling pathways may be key to neuronal plasticity in deafness.
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25
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Kolla L, Kelly MC, Mann ZF, Anaya-Rocha A, Ellis K, Lemons A, Palermo AT, So KS, Mays JC, Orvis J, Burns JC, Hertzano R, Driver EC, Kelley MW. Characterization of the development of the mouse cochlear epithelium at the single cell level. Nat Commun 2020; 11:2389. [PMID: 32404924 PMCID: PMC7221106 DOI: 10.1038/s41467-020-16113-y] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 04/10/2020] [Indexed: 12/14/2022] Open
Abstract
Mammalian hearing requires the development of the organ of Corti, a sensory epithelium comprising unique cell types. The limited number of each of these cell types, combined with their close proximity, has prevented characterization of individual cell types and/or their developmental progression. To examine cochlear development more closely, we transcriptionally profile approximately 30,000 isolated mouse cochlear cells collected at four developmental time points. Here we report on the analysis of those cells including the identification of both known and unknown cell types. Trajectory analysis for OHCs indicates four phases of gene expression while fate mapping of progenitor cells suggests that OHCs and their surrounding supporting cells arise from a distinct (lateral) progenitor pool. Tgfβr1 is identified as being expressed in lateral progenitor cells and a Tgfβr1 antagonist inhibits OHC development. These results provide insights regarding cochlear development and demonstrate the potential value and application of this data set. How the development of the cochlear epithelium is regulated is unclear. Here, the authors use single cell RNAseq analysis to provide insight into the transcriptional changes arising during development of the murine cochlear inner and outer hair cells.
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Affiliation(s)
- Likhitha Kolla
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michael C Kelly
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zoe F Mann
- Centre for Craniofacial and Regenerative Biology, King's College London, London, UK
| | - Alejandro Anaya-Rocha
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kathryn Ellis
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Abigail Lemons
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Adam T Palermo
- Decibel Therapeutics, 1325 Boylston, Str., Suite 500, Boston, MA, 02215, USA
| | - Kathy S So
- Decibel Therapeutics, 1325 Boylston, Str., Suite 500, Boston, MA, 02215, USA
| | - Joseph C Mays
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Joshua Orvis
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Joseph C Burns
- Decibel Therapeutics, 1325 Boylston, Str., Suite 500, Boston, MA, 02215, USA
| | - Ronna Hertzano
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Otorhinolaryngology Head and Neck Surgery, Anatomy and Neurobiology, and Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Elizabeth C Driver
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA.
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26
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Montcouquiol M, Kelley MW. Development and Patterning of the Cochlea: From Convergent Extension to Planar Polarity. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a033266. [PMID: 30617059 DOI: 10.1101/cshperspect.a033266] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Within the mammalian cochlea, sensory hair cells and supporting cells are aligned in curvilinear rows that extend along the length of the tonotopic axis. In addition, all of the cells within the epithelium are uniformly polarized across the orthogonal neural-abneural axis. Finally, each hair cell is intrinsically polarized as revealed by the presence of an asymmetrically shaped and apically localized stereociliary bundle. It has been known for some time that many of the developmental processes that regulate these patterning events are mediated, to some extent, by the core planar cell polarity (PCP) pathway. This article will review more recent work demonstrating how components of the PCP pathway interact with cytoskeletal motor proteins to regulate cochlear outgrowth. Finally, a signaling pathway originally identified for its role in asymmetric cell divisions has recently been shown to mediate several aspects of intrinsic hair cell polarity, including kinocilia migration, bundle shape, and elongation.
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Affiliation(s)
- Mireille Montcouquiol
- INSERM, Neurocentre Magendie, U1215, F-33077 Bordeaux, France.,University of Bordeaux, Neurocentre Magendie, U1215, F-33077 Bordeaux, France
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
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27
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Novel insights into inner ear development and regeneration for targeted hearing loss therapies. Hear Res 2019; 397:107859. [PMID: 31810596 DOI: 10.1016/j.heares.2019.107859] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/06/2019] [Accepted: 11/25/2019] [Indexed: 02/06/2023]
Abstract
Sensorineural hearing loss is the most common sensory deficit in humans. Despite the global scale of the problem, only limited treatment options are available today. The mammalian inner ear is a highly specialized postmitotic organ, which lacks proliferative or regenerative capacity. Since the discovery of hair cell regeneration in non-mammalian species however, much attention has been placed on identifying possible strategies to reactivate similar responses in humans. The development of successful regenerative approaches for hearing loss strongly depends on a detailed understanding of the mechanisms that control human inner ear cellular specification, differentiation and function, as well as on the development of robust in vitro cellular assays, based on human inner ear cells, to study these processes and optimize therapeutic interventions. We summarize here some aspects of inner ear development and strategies to induce regeneration that have been investigated in rodents. Moreover, we discuss recent findings in human inner ear development and compare the results with findings from animal models. Finally, we provide an overview of strategies for in vitro generation of human sensory cells from pluripotent and somatic progenitors that may provide a platform for drug development and validation of therapeutic strategies in vitro.
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28
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Munnamalai V, Fekete DM. The acquisition of positional information across the radial axis of the cochlea. Dev Dyn 2019; 249:281-297. [PMID: 31566832 DOI: 10.1002/dvdy.118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Vidhya Munnamalai
- The Jackson Laboratory Bar Harbor Maine
- Graduate Program of Biomedical Sciences and EngineeringUniversity of Maine Orono Maine
- The Neuroscience ProgramSackler School of Biomedical Sciences, Tufts University Boston Massachusetts
| | - Donna M. Fekete
- Department of Biological SciencesPurdue University West Lafayette Indiana
- Purdue Institute for Integrative Neuroscience West Lafayette Indiana
- Purdue Center for Cancer Research West Lafayette Indiana
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29
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Muthu V, Rohacek AM, Yao Y, Rakowiecki SM, Brown AS, Zhao YT, Meyers J, Won KJ, Ramdas S, Brown CD, Peterson KA, Epstein DJ. Genomic architecture of Shh-dependent cochlear morphogenesis. Development 2019; 146:dev.181339. [PMID: 31488567 DOI: 10.1242/dev.181339] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/23/2019] [Indexed: 12/19/2022]
Abstract
The mammalian cochlea develops from a ventral outgrowth of the otic vesicle in response to Shh signaling. Mouse embryos lacking Shh or its essential signal transduction components display cochlear agenesis; however, a detailed understanding of the transcriptional network mediating this process is unclear. Here, we describe an integrated genomic approach to identify Shh-dependent genes and associated regulatory sequences that promote cochlear duct morphogenesis. A comparative transcriptome analysis of otic vesicles from mouse mutants exhibiting loss (Smoecko ) and gain (Shh-P1) of Shh signaling reveal a set of Shh-responsive genes partitioned into four expression categories in the ventral half of the otic vesicle. This target gene classification scheme provides novel insight into several unanticipated roles for Shh, including priming the cochlear epithelium for subsequent sensory development. We also mapped regions of open chromatin in the inner ear by ATAC-seq that, in combination with Gli2 ChIP-seq, identified inner ear enhancers in the vicinity of Shh-responsive genes. These datasets are useful entry points for deciphering Shh-dependent regulatory mechanisms involved in cochlear duct morphogenesis and establishment of its constituent cell types.
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Affiliation(s)
- Victor Muthu
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alex M Rohacek
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yao Yao
- Department of Animal and Dairy Science, Regenerative Bioscience Center, University of Georgia, Athens, GA 30602, USA
| | - Staci M Rakowiecki
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexander S Brown
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ying-Tao Zhao
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Meyers
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyoung-Jae Won
- Biotech Research and Innovation Centre (BRIC), Novo Nordisk Foundation Center for Stem Cell Biology, DanStem, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Shweta Ramdas
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher D Brown
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Douglas J Epstein
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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30
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Jung JS, Zhang KD, Wang Z, McMurray M, Tkaczuk A, Ogawa Y, Hertzano R, Coate TM. Semaphorin-5B Controls Spiral Ganglion Neuron Branch Refinement during Development. J Neurosci 2019; 39:6425-6438. [PMID: 31209173 PMCID: PMC6697390 DOI: 10.1523/jneurosci.0113-19.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/03/2019] [Accepted: 06/10/2019] [Indexed: 01/30/2023] Open
Abstract
During nervous system development, axons often undergo elaborate changes in branching patterns before circuits have achieved their mature patterns of innervation. In the auditory system, type I spiral ganglion neurons (SGNs) project their peripheral axons into the cochlear epithelium and then undergo a process of branch refinement before forming synapses with sensory hair cells. Here, we report that Semaphorin-5B (Sema5B) acts as an important mediator of this process. During cochlear development in mouse, immature hair cells express Sema5B, whereas the SGNs express both PlexinA1 and PlexinA3, which are known Sema5B receptors. In these studies, genetic sparse labeling and three-dimensional reconstruction techniques were leveraged to determine the morphologies of individual type I SGNs after manipulations of Sema5B signaling. Treating cultured mouse cochleae with Sema5B-Fc (to activate Plexin-As) led to type I SGNs with less numerous, but longer terminal branches. Conversely, cochleae from Sema5b knock-out mice showed type I SGNs with more numerous, but shorter terminal branches. In addition, conditional loss of Plxna1 in SGNs (using Bhlhb5Cre) led to increased type I SGN branching, suggesting that PlexinA1 normally responds to Sema5B in this process. In these studies, mice of either sex were used. The data presented here suggest that Sema5B-PlexinA1 signaling limits SGN terminal branch numbers without causing axonal repulsion, which is a role that distinguishes Sema5B from other Semaphorins in cochlear development.SIGNIFICANCE STATEMENT The sensorineural components of the cochlea include hair cells, which respond mechanically to sound waves, and afferent spiral ganglion neurons (SGNs), which respond to glutamate released by hair cells and transmit auditory information into the CNS. An important component of synapse formation in the cochlea is a process of SGN "debranching" whereby SGNs lose extraneous branches before developing unramified bouton endings that contact the hair cells. In this work, we have found that the transmembrane ligand Semaphorin-5B and its receptor PlexinA1 regulate the debranching process. The results in this report provide new knowledge regarding the molecular control of cochlear afferent innervation.
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Affiliation(s)
- Johnny S Jung
- Department of Biology, Georgetown University, Washington, DC 20007, and
| | - Kaidi D Zhang
- Department of Biology, Georgetown University, Washington, DC 20007, and
| | - Zhirong Wang
- Department of Biology, Georgetown University, Washington, DC 20007, and
| | - Mark McMurray
- Departments of Otorhinolaryngology Head and Neck Surgery
| | - Andrew Tkaczuk
- Departments of Otorhinolaryngology Head and Neck Surgery
| | - Yoko Ogawa
- Departments of Otorhinolaryngology Head and Neck Surgery
| | - Ronna Hertzano
- Departments of Otorhinolaryngology Head and Neck Surgery
- Anatomy and Neurobiology, and
- Institute for Genome Sciences, University of Maryland School of Medicine, University of Maryland, Baltimore, Maryland 21201
| | - Thomas M Coate
- Department of Biology, Georgetown University, Washington, DC 20007, and
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31
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Xia M, Ma J, Sun S, Li W, Li H. The biological strategies for hearing re-establishment based on the stem/progenitor cells. Neurosci Lett 2019; 711:134406. [PMID: 31377244 DOI: 10.1016/j.neulet.2019.134406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/18/2019] [Accepted: 07/27/2019] [Indexed: 01/04/2023]
Abstract
The cochlea is the essential organ for hearing and includes both auditory sensory hair cells and spiral ganglion neurons. The discovery of inner ear stem cell brings hope to the regeneration of hair cell and spiral ganglion neuron as well as the followed hearing re-establishment. Thus the investigation on characteristics of inner ear stem/progenitor cells and related regulating clue is important to make such regeneration a reality. In addition, attempts have also been made to transplant exogenous stem cells into the inner ear to restore hearing function. In this review, we describe recent advances in the characterization of mammalian inner ear progenitor/stem cells and the mechanisms of regulating their proliferation and differentiation, and summarize studies that have used exogenous stem cells to repair damaged hair cells and neurons in the inner ear.
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Affiliation(s)
- Mingyu Xia
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Jiaoyao Ma
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200031, China; Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China; NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China; Shanghai Engineering Research Centre of Cochlear Implant, Shanghai, 200031, China; The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
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32
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Prajapati-DiNubila M, Benito-Gonzalez A, Golden EJ, Zhang S, Doetzlhofer A. A counter gradient of Activin A and follistatin instructs the timing of hair cell differentiation in the murine cochlea. eLife 2019; 8:47613. [PMID: 31187730 PMCID: PMC6561706 DOI: 10.7554/elife.47613] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 05/27/2019] [Indexed: 12/14/2022] Open
Abstract
The mammalian auditory sensory epithelium has one of the most stereotyped cellular patterns known in vertebrates. Mechano-sensory hair cells are arranged in precise rows, with one row of inner and three rows of outer hair cells spanning the length of the spiral-shaped sensory epithelium. Aiding such precise cellular patterning, differentiation of the auditory sensory epithelium is precisely timed and follows a steep longitudinal gradient. The molecular signals that promote auditory sensory differentiation and instruct its graded pattern are largely unknown. Here, we identify Activin A and its antagonist follistatin as key regulators of hair cell differentiation and show, using mouse genetic approaches, that a local gradient of Activin A signaling within the auditory sensory epithelium times the longitudinal gradient of hair cell differentiation. Furthermore, we provide evidence that Activin-type signaling regulates a radial gradient of terminal mitosis within the auditory sensory epithelium, which constitutes a novel mechanism for limiting the number of inner hair cells being produced.
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Affiliation(s)
- Meenakshi Prajapati-DiNubila
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Ana Benito-Gonzalez
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Erin Jennifer Golden
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Shuran Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Angelika Doetzlhofer
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, United States
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33
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GSK3 regulates hair cell fate in the developing mammalian cochlea. Dev Biol 2019; 453:191-205. [PMID: 31185200 DOI: 10.1016/j.ydbio.2019.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 06/07/2019] [Accepted: 06/07/2019] [Indexed: 12/27/2022]
Abstract
The development of asymmetric patterns along biologically relevant axes is a hallmark of many vertebrate organs or structures. One example is the sensory epithelium of the mammalian auditory system. Two distinct types of mechanosensory hair cells (inner and outer) and at least six types of associated supporting cells are precisely and asymmetrically arrayed along the radial (medial-lateral) axis of the cochlear spiral. Immunolabeling of developing cochleae indicates differential expression of Glycogen synthase kinase 3β (GSK3β) along the same axis. To determine whether GSK3β plays a role in specification of cell fates along the medial-lateral axis, GSK3 activity was blocked pharmacologically in cochlear explants. Results indicate significant changes in both the number of hair cells and in the specification of hair cell phenotypes. The overall number of inner hair cells increased as a result of both a shift in the medial boundary between sensory and non-sensory regions of the cochlea and a change in the specification of inner and outer hair cell phenotypes. Previous studies have inhibited GSK3 as a method to examine effects of canonical Wnt signaling. However, quantification of changes in Wnt pathway target genes in GSK3-inhibited cochleae, and treatment with more specific Wnt agonists, indicated that the Wnt pathway is not activated. Instead, expression of Bmp4 in a population of GSK3β-expressing cells was shown to be down-regulated. Finally, addition of BMP4 to GSK3-inhibited cochleae achieved a partial rescue of the hair cell phenotype. These results demonstrate a role for GSK3β in the specification of cellular identities along the medial-lateral axis of the cochlea and provide evidence for a positive role for GSK3β in the expression of Bmp4.
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35
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Harley RJ, Murdy JP, Wang Z, Kelly MC, Ropp TJF, Park SH, Maness PF, Manis PB, Coate TM. Neuronal cell adhesion molecule (NrCAM) is expressed by sensory cells in the cochlea and is necessary for proper cochlear innervation and sensory domain patterning during development. Dev Dyn 2018; 247:934-950. [PMID: 29536590 PMCID: PMC6105381 DOI: 10.1002/dvdy.24629] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 03/06/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND In the cochlea, auditory development depends on precise patterns of innervation by afferent and efferent nerve fibers, as well as a stereotyped arrangement of hair and supporting cells. Neuronal cell adhesion molecule (NrCAM) is a homophilic cell adhesion molecule that controls diverse aspects of nervous system development, but the function of NrCAM in cochlear development is not well understood. RESULTS Throughout cochlear innervation, NrCAM is detectable on spiral ganglion neuron (SGN) afferent and olivocochlear efferent fibers, and on the membranes of developing hair and supporting cells. Neonatal Nrcam-null cochleae show errors in type II SGN fasciculation, reduced efferent innervation, and defects in the stereotyped packing of hair and supporting cells. Nrcam loss also leads to dramatic changes in the profiles of presynaptic afferent and efferent synaptic markers at the time of hearing onset. Despite these numerous developmental defects, Nrcam-null adults do not show defects in auditory acuity, and by postnatal day 21, the developmental deficits in ribbon synapse distribution and sensory domain structure appear to have been corrected. CONCLUSIONS NrCAM is expressed by several neural and sensory epithelial subtypes within the developing cochlea, and the loss of Nrcam confers numerous, but nonpermanent, developmental defects in innervation and sensory domain patterning. Developmental Dynamics 247:934-950, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Randall J. Harley
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Joseph P. Murdy
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Zhirong Wang
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Michael C. Kelly
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, 35 Convent Dr., Bethesda, MD 20892, USA
| | - Tessa-Jonne F. Ropp
- Department of Otolaryngology/Head and Neck Surgery, The University of North Carolina at Chapel Hill, B251 Marsico Hall, CB#7070, 125 Mason Farm Rd., Chapel Hill, NC 27599, USA
| | - SeHoon H. Park
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
| | - Patricia F. Maness
- Department of Biochemistry and Biophysics, The University of North Carolina School of Medicine, 120 Mason Farm Rd., suite 3020, CB#7260, Chapel Hill, NC 27599, USA
| | - Paul B. Manis
- Department of Otolaryngology/Head and Neck Surgery and Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, B027 Marsico Hall, CB#7070. 125 Mason Farm Rd., Chapel Hill, NC 27599
| | - Thomas M. Coate
- Department of Biology, Georgetown University, 37 and O St. NW, Regents Hall 410, Washington, DC 20007, USA
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36
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Bozal-Basterra L, Martín-Ruíz I, Pirone L, Liang Y, Sigurðsson JO, Gonzalez-Santamarta M, Giordano I, Gabicagogeascoa E, de Luca A, Rodríguez JA, Wilkie AO, Kohlhase J, Eastwood D, Yale C, Olsen JV, Rauchman M, Anderson KV, Sutherland JD, Barrio R. Truncated SALL1 Impedes Primary Cilia Function in Townes-Brocks Syndrome. Am J Hum Genet 2018; 102:249-265. [PMID: 29395072 PMCID: PMC5985538 DOI: 10.1016/j.ajhg.2017.12.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 12/19/2017] [Indexed: 12/21/2022] Open
Abstract
Townes-Brocks syndrome (TBS) is characterized by a spectrum of malformations in the digits, ears, and kidneys. These anomalies overlap those seen in a growing number of ciliopathies, which are genetic syndromes linked to defects in the formation or function of the primary cilia. TBS is caused by mutations in the gene encoding the transcriptional repressor SALL1 and is associated with the presence of a truncated protein that localizes to the cytoplasm. Here, we provide evidence that SALL1 mutations might cause TBS by means beyond its transcriptional capacity. By using proximity proteomics, we show that truncated SALL1 interacts with factors related to cilia function, including the negative regulators of ciliogenesis CCP110 and CEP97. This most likely contributes to more frequent cilia formation in TBS-derived fibroblasts, as well as in a CRISPR/Cas9-generated model cell line and in TBS-modeled mouse embryonic fibroblasts, than in wild-type controls. Furthermore, TBS-like cells show changes in cilia length and disassembly rates in combination with aberrant SHH signaling transduction. These findings support the hypothesis that aberrations in primary cilia and SHH signaling are contributing factors in TBS phenotypes, representing a paradigm shift in understanding TBS etiology. These results open possibilities for the treatment of TBS.
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37
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Chen Y, Lu X, Guo L, Ni W, Zhang Y, Zhao L, Wu L, Sun S, Zhang S, Tang M, Li W, Chai R, Li H. Hedgehog Signaling Promotes the Proliferation and Subsequent Hair Cell Formation of Progenitor Cells in the Neonatal Mouse Cochlea. Front Mol Neurosci 2017; 10:426. [PMID: 29311816 PMCID: PMC5742997 DOI: 10.3389/fnmol.2017.00426] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 12/06/2017] [Indexed: 12/11/2022] Open
Abstract
Hair cell (HC) loss is the major cause of permanent sensorineural hearing loss in mammals. Unlike lower vertebrates, mammalian cochlear HCs cannot regenerate spontaneously after damage, although the vestibular system does maintain limited HC regeneration capacity. Thus HC regeneration from the damaged sensory epithelium has been one of the main areas of research in the field of hearing restoration. Hedgehog signaling plays important roles during the embryonic development of the inner ear, and it is involved in progenitor cell proliferation and differentiation as well as the cell fate decision. In this study, we show that recombinant Sonic Hedgehog (Shh) protein effectively promotes sphere formation, proliferation, and differentiation of Lgr5+ progenitor cells isolated from the neonatal mouse cochlea. To further explore this, we determined the effect of Hedgehog signaling on cell proliferation and HC regeneration in cultured cochlear explant from transgenic R26-SmoM2 mice that constitutively activate Hedgehog signaling in the supporting cells of the cochlea. Without neomycin treatment, up-regulation of Hedgehog signaling did not significantly promote cell proliferation or new HC formation. However, after injury to the sensory epithelium by neomycin treatment, the over-activation of Hedgehog signaling led to significant supporting cell proliferation and HC regeneration in the cochlear epithelium explants. RNA sequencing and real-time PCR were used to compare the transcripts of the cochleae from control mice and R26-SmoM2 mice, and multiple genes involved in the proliferation and differentiation processes were identified. This study has important implications for the treatment of sensorineural hearing loss by manipulating the Hedgehog signaling pathway.
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Affiliation(s)
- Yan Chen
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Xiaoling Lu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Wenli Ni
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Yanping Zhang
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Liping Zhao
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Lingjie Wu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Shan Sun
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Shasha Zhang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Mingliang Tang
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China.,Shanghai Engineering Research Centre of Cochlear Implant, Shanghai, China
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38
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Kelley MW, Stone JS. Development and Regeneration of Sensory Hair Cells. AUDITORY DEVELOPMENT AND PLASTICITY 2017. [DOI: 10.1007/978-3-319-21530-3_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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39
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On the mechanism of smell loss in patients with Type II congenital hyposmia. Am J Otolaryngol 2016; 37:436-41. [PMID: 27221029 DOI: 10.1016/j.amjoto.2016.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 11/23/2022]
Abstract
BACKGROUND Smell function has been initiated with theophylline treatment in 63% of patients with Type II congenital smell loss. Based upon a systematic evaluation of the protein components of nasal mucus we have demonstrated that interactions among four chemical moieties in nasal mucus may play significant roles in this initiation. Prior to treatment three of these moieties, cAMP, cGMP and sonic hedgehog (Shh), were significantly decreased in concentration whereas one of these moieties, TNFalpha, was increased in concentration. The mechanism(s) responsible for initiation of smell function in these patients, not immediately apparent, may depend upon understanding interactions among these moieties. METHODS Measurements of cAMP, cGMP, Shh and TNFalpha in nasal mucus by specific spectrophotometric immunoassays before and after treatment with theophylline. RESULTS Before theophylline treatment cAMP, cGMP and Shh in nasal mucus, which act as growth factors to support olfactory receptor function, were significantly decreased below normal levels whereas TNFalpha which acts as a "death factor" to inhibit olfactory receptor function was significantly increased above normal. After theophylline treatment cAMP, cGMP and Shh increased significantly whereas TNFalpha decreased significantly. CONCLUSIONS These results indicate that there are specific biochemical changes associated with smell loss in patients with Type II congenital smell loss and that correction of these biochemical changes are associated with initiation of smell function in these patients. Understanding these relationships play an important role in understanding receptor action in smell function.
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40
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Puligilla C, Kelley MW. Dual role for Sox2 in specification of sensory competence and regulation of Atoh1 function. Dev Neurobiol 2016; 77:3-13. [PMID: 27203669 DOI: 10.1002/dneu.22401] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 11/08/2022]
Abstract
The formation of inner ear sensory epithelia is believed to occur in two steps, initial specification of sensory competent (prosensory) regions followed by determination of specific cell-types, such as hair cells (HCs) and supporting cells. However, studies in which the HC determination factor Atoh1 was ectopically expressed in nonprosensory regions indicated that expression of Atoh1 alone is sufficient to induce HC formation suggesting that prosensory formation may not be a prerequisite for HC development. To test this hypothesis, interactions between Sox2 and Atoh1, which are required for prosensory and HC formation respectively, were examined. Forced expression of Atoh1 in nonprosensory cells resulted in transient expression of Sox2 prior to HC formation, suggesting that expression of Sox2 is required for formation of ectopic HCs. Moreover, Atoh1 overexpression failed to induce HC formation in Sox2 mutants, confirming that Sox2 is required for prosensory competence. To determine whether expression of Sox2 alone is sufficient to induce prosensory identity, Sox2 was transiently activated in a manner that mimicked endogenous expression. Following transient Sox2 activation, nonprosensory cells developed as HCs, a result that was never observed in response to persistent expression of Sox2. These results, suggest a dual role for Sox2 in inner ear formation. Initially, Sox2 is required to specify prosensory competence, but subsequent down-regulation of Sox2 must occur to allow Atoh1 expression, most likely through a direct interaction with the Atoh1 promoter. These results implicate Sox2-mediated changes in prosensory cells as an essential step in their ability to develop as HCs. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 3-13, 2017.
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Affiliation(s)
- Chandrakala Puligilla
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina, 29425
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, 20982
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41
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Basch ML, Brown RM, Jen H, Groves AK. Where hearing starts: the development of the mammalian cochlea. J Anat 2016; 228:233-54. [PMID: 26052920 PMCID: PMC4718162 DOI: 10.1111/joa.12314] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2015] [Indexed: 12/11/2022] Open
Abstract
The mammalian cochlea is a remarkable sensory organ, capable of perceiving sound over a range of 10(12) in pressure, and discriminating both infrasonic and ultrasonic frequencies in different species. The sensory hair cells of the mammalian cochlea are exquisitely sensitive, responding to atomic-level deflections at speeds on the order of tens of microseconds. The number and placement of hair cells are precisely determined during inner ear development, and a large number of developmental processes sculpt the shape, size and morphology of these cells along the length of the cochlear duct to make them optimally responsive to different sound frequencies. In this review, we briefly discuss the evolutionary origins of the mammalian cochlea, and then describe the successive developmental processes that lead to its induction, cell cycle exit, cellular patterning and the establishment of topologically distinct frequency responses along its length.
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Affiliation(s)
- Martin L. Basch
- Department of NeuroscienceBaylor College of MedicineHoustonTXUSA
| | - Rogers M. Brown
- Program in Developmental BiologyBaylor College of MedicineHoustonTXUSA
| | - Hsin‐I Jen
- Program in Developmental BiologyBaylor College of MedicineHoustonTXUSA
| | - Andrew K. Groves
- Department of NeuroscienceBaylor College of MedicineHoustonTXUSA
- Program in Developmental BiologyBaylor College of MedicineHoustonTXUSA
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTXUSA
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42
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Coate TM, Spita NA, Zhang KD, Isgrig KT, Kelley MW. Neuropilin-2/Semaphorin-3F-mediated repulsion promotes inner hair cell innervation by spiral ganglion neurons. eLife 2015; 4. [PMID: 26302206 PMCID: PMC4566076 DOI: 10.7554/elife.07830] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/22/2015] [Indexed: 12/18/2022] Open
Abstract
Auditory function is dependent on the formation of specific innervation patterns between mechanosensory hair cells (HCs) and afferent spiral ganglion neurons (SGNs). In particular, type I SGNs must precisely connect with inner HCs (IHCs) while avoiding connections with nearby outer HCs (OHCs). The factors that mediate these patterning events are largely unknown. Using sparse-labeling and time-lapse imaging, we visualized for the first time the behaviors of developing SGNs including active retraction of processes from OHCs, suggesting that some type I SGNs contact OHCs before forming synapses with IHCs. In addition, we demonstrate that expression of Semaphorin-3F in the OHC region inhibits type I SGN process extension by activating Neuropilin-2 receptors expressed on SGNs. These results suggest a model in which cochlear innervation patterns by type I SGNs are determined, at least in part, through a Semaphorin-3F-mediated inhibitory signal that impedes processes from extending beyond the IHC region. DOI:http://dx.doi.org/10.7554/eLife.07830.001 The process of hearing begins when sound waves enter the outer ear, causing the eardrum to vibrate. The three small bones of the middle ear pass these vibrations on to the cochlea, a fluid-filled structure shaped like a spiral. Tiny hair cells inside the cochlea move in response to the vibrations and convert them into electrical signals, which are transmitted by cells called spiral ganglion neurons (SGNs) to the brain. Hair cells can be divided into ‘inner’ and ‘outer’ hair cells. Inner hair cells transmit most of the information about a sound to the brain, via connections with type I SGNs. Outer hair cells are thought to amplify sound and connect to type II SGNs. How the type I and II SGNs connect to the correct type of hair cell as the ear develops is not well understood, despite these connections being essential for hearing. Coate et al. have now used time-lapse imaging and fixed specimens to follow individually labeled SGNs as they establish these connections within the cochlea of a mouse embryo. Although the type I SGNs ultimately formed connections with inner hair cells, many of them made contact with outer hair cells first. These contacts were short-lived thanks to a protein found near the outer hair cells, named Semaphorin-3F. This protein repels the type I SGNs by activating a receptor on their surface called Neuropilin-2, and so directs the type I SGNs towards the inner hair cells. One of the mysteries that remains to be solved is how type II SGNs are ‘permitted’ to extend into the outer hair cell region, even though they are also confronted by Semaphorin-3F. In addition, it will also be important to determine how SGNs adapt to cues from different Semaphorins from different parts of the cochlea as they navigate into different hair cell regions. DOI:http://dx.doi.org/10.7554/eLife.07830.002
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Affiliation(s)
- Thomas M Coate
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, Bethesda, United States
| | - Nathalie A Spita
- Department of Biology, Georgetown University, Washington, United States
| | - Kaidi D Zhang
- Department of Biology, Georgetown University, Washington, United States
| | - Kevin T Isgrig
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, Bethesda, United States
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, Bethesda, United States
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43
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Atkinson PJ, Huarcaya Najarro E, Sayyid ZN, Cheng AG. Sensory hair cell development and regeneration: similarities and differences. Development 2015; 142:1561-71. [PMID: 25922522 DOI: 10.1242/dev.114926] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Sensory hair cells are mechanoreceptors of the auditory and vestibular systems and are crucial for hearing and balance. In adult mammals, auditory hair cells are unable to regenerate, and damage to these cells results in permanent hearing loss. By contrast, hair cells in the chick cochlea and the zebrafish lateral line are able to regenerate, prompting studies into the signaling pathways, morphogen gradients and transcription factors that regulate hair cell development and regeneration in various species. Here, we review these findings and discuss how various signaling pathways and factors function to modulate sensory hair cell development and regeneration. By comparing and contrasting development and regeneration, we also highlight the utility and limitations of using defined developmental cues to drive mammalian hair cell regeneration.
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Affiliation(s)
- Patrick J Atkinson
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elvis Huarcaya Najarro
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zahra N Sayyid
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alan G Cheng
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
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44
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Ohnishi H, Skerleva D, Kitajiri SI, Sakamoto T, Yamamoto N, Ito J, Nakagawa T. Limited hair cell induction from human induced pluripotent stem cells using a simple stepwise method. Neurosci Lett 2015; 599:49-54. [PMID: 26003451 DOI: 10.1016/j.neulet.2015.05.032] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/16/2015] [Accepted: 05/18/2015] [Indexed: 12/23/2022]
Abstract
Disease-specific induced pluripotent stem cells (iPS) cells are expected to contribute to exploring useful tools for studying the pathophysiology of inner ear diseases and to drug discovery for treating inner ear diseases. For this purpose, stable induction methods for the differentiation of human iPS cells into inner ear hair cells are required. In the present study, we examined the efficacy of a simple induction method for inducing the differentiation of human iPS cells into hair cells. The induction of inner ear hair cell-like cells was performed using a stepwise method mimicking inner ear development. Human iPS cells were sequentially transformed into the preplacodal ectoderm, otic placode, and hair cell-like cells. As a first step, preplacodal ectoderm induction, human iPS cells were seeded on a Matrigel-coated plate and cultured in a serum free N2/B27 medium for 8 days according to a previous study that demonstrated spontaneous differentiation of human ES cells into the preplacodal ectoderm. As the second step, the cells after preplacodal ectoderm induction were treated with basic fibroblast growth factor (bFGF) for induction of differentiation into otic-placode-like cells for 15 days. As the final step, cultured cells were incubated in a serum free medium containing Matrigel for 48 days. After preplacodal ectoderm induction, over 90% of cultured cells expressed the genes that express in preplacodal ectoderm. By culture with bFGF, otic placode marker-positive cells were obtained, although their number was limited. Further 48-day culture in serum free media resulted in the induction of hair cell-like cells, which expressed a hair cell marker and had stereocilia bundle-like constructions on their apical surface. Our results indicate that hair cell-like cells are induced from human iPS cells using a simple stepwise method with only bFGF, without the use of xenogeneic cells.
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Affiliation(s)
- Hiroe Ohnishi
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Desislava Skerleva
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shin-ichiro Kitajiri
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tatsunori Sakamoto
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Norio Yamamoto
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Juichi Ito
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takayuki Nakagawa
- Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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45
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Conserved role of Sonic Hedgehog in tonotopic organization of the avian basilar papilla and mammalian cochlea. Proc Natl Acad Sci U S A 2015; 112:3746-51. [PMID: 25775517 DOI: 10.1073/pnas.1417856112] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sound frequency discrimination begins at the organ of Corti in mammals and the basilar papilla in birds. Both of these hearing organs are tonotopically organized such that sensory hair cells at the basal (proximal) end respond to high frequency sound, whereas their counterparts at the apex (distal) respond to low frequencies. Sonic hedgehog (Shh) secreted by the developing notochord and floor plate is required for cochlear formation in both species. In mice, the apical region of the developing cochlea, closer to the ventral midline source of Shh, requires higher levels of Shh signaling than the basal cochlea farther away from the midline. Here, gain-of-function experiments using Shh-soaked beads in ovo or a mouse model expressing constitutively activated Smoothened (transducer of Shh signaling) show up-regulation of apical genes in the basal cochlea, even though these regionally expressed genes are not necessarily conserved between the two species. In chicken, these altered gene expression patterns precede morphological and physiological changes in sensory hair cells that are typically associated with tonotopy such as the total number of stereocilia per hair cell and gene expression of an inward rectifier potassium channel, IRK1, which is a bona fide feature of apical hair cells in the basilar papilla. Furthermore, our results suggest that this conserved role of Shh in establishing cochlear tonotopy is initiated early in development by Shh emanating from the notochord and floor plate.
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46
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Hey1 and Hey2 control the spatial and temporal pattern of mammalian auditory hair cell differentiation downstream of Hedgehog signaling. J Neurosci 2014; 34:12865-76. [PMID: 25232121 DOI: 10.1523/jneurosci.1494-14.2014] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mechano-sensory hair cells (HCs), housed in the inner ear cochlea, are critical for the perception of sound. In the mammalian cochlea, differentiation of HCs occurs in a striking basal-to-apical and medial-to-lateral gradient, which is thought to ensure correct patterning and proper function of the auditory sensory epithelium. Recent studies have revealed that Hedgehog signaling opposes HC differentiation and is critical for the establishment of the graded pattern of auditory HC differentiation. However, how Hedgehog signaling interferes with HC differentiation is unknown. Here, we provide evidence that in the murine cochlea, Hey1 and Hey2 control the spatiotemporal pattern of HC differentiation downstream of Hedgehog signaling. It has been recently shown that HEY1 and HEY2, two highly redundant HES-related transcriptional repressors, are highly expressed in supporting cell (SC) and HC progenitors (prosensory cells), but their prosensory function remained untested. Using a conditional double knock-out strategy, we demonstrate that prosensory cells form and proliferate properly in the absence of Hey1 and Hey2 but differentiate prematurely because of precocious upregulation of the pro-HC factor Atoh1. Moreover, we demonstrate that prosensory-specific expression of Hey1 and Hey2 and its subsequent graded downregulation is controlled by Hedgehog signaling in a largely FGFR-dependent manner. In summary, our study reveals a critical role for Hey1 and Hey2 in prosensory cell maintenance and identifies Hedgehog signaling as a novel upstream regulator of their prosensory function in the mammalian cochlea. The regulatory mechanism described here might be a broadly applied mechanism for controlling progenitor behavior in the central and peripheral nervous system.
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47
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Sensational placodes: neurogenesis in the otic and olfactory systems. Dev Biol 2014; 389:50-67. [PMID: 24508480 PMCID: PMC3988839 DOI: 10.1016/j.ydbio.2014.01.023] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 01/27/2014] [Accepted: 01/28/2014] [Indexed: 11/22/2022]
Abstract
For both the intricate morphogenetic layout of the sensory cells in the ear and the elegantly radial arrangement of the sensory neurons in the nose, numerous signaling molecules and genetic determinants are required in concert to generate these specialized neuronal populations that help connect us to our environment. In this review, we outline many of the proteins and pathways that play essential roles in the differentiation of otic and olfactory neurons and their integration into their non-neuronal support structures. In both cases, well-known signaling pathways together with region-specific factors transform thickened ectodermal placodes into complex sense organs containing numerous, diverse neuronal subtypes. Olfactory and otic placodes, in combination with migratory neural crest stem cells, generate highly specialized subtypes of neuronal cells that sense sound, position and movement in space, odors and pheromones throughout our lives.
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48
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Tateya T, Imayoshi I, Tateya I, Hamaguchi K, Torii H, Ito J, Kageyama R. Hedgehog signaling regulates prosensory cell properties during the basal-to-apical wave of hair cell differentiation in the mammalian cochlea. Development 2013; 140:3848-57. [PMID: 23946445 DOI: 10.1242/dev.095398] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mechanosensory hair cells and supporting cells develop from common precursors located in the prosensory domain of the developing cochlear epithelium. Prosensory cell differentiation into hair cells or supporting cells proceeds from the basal to the apical region of the cochleae, but the mechanism and significance of this basal-to-apical wave of differentiation remain to be elucidated. Here, we investigated the role of Hedgehog (Hh) signaling in cochlear development by examining the effects of up- and downregulation of Hh signaling in vivo. The Hh effector smoothened (Smo) was genetically activated or inactivated specifically in the developing cochlear epithelium after prosensory domain formation. Cochleae expressing a constitutively active allele of Smo showed only one row of inner hair cells with no outer hair cells (OHCs); abnormal undifferentiated prosensory-like cells were present in the lateral compartment instead of OHCs and their adjacent supporting cells. This suggests that Hh signaling inhibits prosensory cell differentiation into hair cells or supporting cells and maintains their properties as prosensory cells. Conversely, in cochlea with the Smo conditional knockout (Smo CKO), hair cell differentiation was preferentially accelerated in the apical region. Smo CKO mice survived after birth, and exhibited hair cell disarrangement in the apical region, a decrease in hair cell number, and hearing impairment. These results indicate that Hh signaling delays hair cell and supporting cell differentiation in the apical region, which forms the basal-to-apical wave of development, and is required for the proper differentiation, arrangement and survival of hair cells and for hearing ability.
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Affiliation(s)
- Tomoko Tateya
- Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
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49
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Auditory ganglion source of Sonic hedgehog regulates timing of cell cycle exit and differentiation of mammalian cochlear hair cells. Proc Natl Acad Sci U S A 2013; 110:13869-74. [PMID: 23918393 DOI: 10.1073/pnas.1222341110] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Neural precursor cells of the central nervous system undergo successive temporal waves of terminal division, each of which is soon followed by the onset of cell differentiation. The organ of Corti in the mammalian cochlea develops differently, such that precursors at the apex are the first to exit from the cell cycle but the last to begin differentiating as mechanosensory hair cells. Using a tissue-specific knockout approach in mice, we show that this unique temporal pattern of sensory cell development requires that the adjacent auditory (spiral) ganglion serve as a source of the signaling molecule Sonic hedgehog (Shh). In the absence of this signaling, the cochlear duct is shortened, sensory hair cell precursors exit from the cell cycle prematurely, and hair cell differentiation closely follows cell cycle exit in a similar apical-to-basal direction. The dynamic relationship between the restriction of Shh expression in the developing spiral ganglion and its proximity to regions of the growing cochlear duct dictates the timing of terminal mitosis of hair cell precursors and their subsequent differentiation.
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Mulvaney JF, Yatteau A, Sun WW, Jacques B, Takubo K, Suda T, Yamada W, Dabdoub A. Secreted factor R-Spondin 2 is involved in refinement of patterning of the mammalian cochlea. Dev Dyn 2013. [PMID: 23192966 DOI: 10.1002/dvdy.23908] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND In the cochlea, patterning of the organ of Corti is tightly regulated to produce a single row of sound-detecting inner hair cells and three rows of outer hair cells, which amplify and refine the signal. The recently identified R-Spondin family of signaling molecules usually act as co-activators of Wnt signaling; it is thought that they regulate turnover of Wnt receptors at the membrane. We sought to test whether R-Spondins function in the developing cochlea. RESULTS Expression analysis of all four members of the R-Spondin family showed that only R-Spondin2 (Rspo2) is expressed in the cochlea during development of the sensory epithelium. Examination of an Rspo2(-/-) mouse showed that loss of Rspo2 results in an additional single row of outer hair cells and disruption of peripheral innervation pattern. Addition of Rspo2 recombinant protein to organotypic cochlear cultures resulted in a small but significant decrease in the number of outer hair cells. CONCLUSIONS Rspo2 is required to limit the number of outer hair cells to three rows and for optimal arrangement of peripheral nerve fibers. The Rspo2 gain- and loss-of-function studies show that in the ear, Rspo2 function is not consistent with its assigned role as a Wnt potentiator.
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Affiliation(s)
- J F Mulvaney
- Division of Otolaryngology, Department of Surgery, School of Medicine, University of California, San Diego, La Jolla, CA, USA.
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