1
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Lipovsek M. Comparative biology of the amniote vestibular utricle. Hear Res 2024; 448:109035. [PMID: 38763033 DOI: 10.1016/j.heares.2024.109035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/21/2024]
Abstract
The sensory epithelia of the auditory and vestibular systems of vertebrates have shared developmental and evolutionary histories. However, while the auditory epithelia show great variation across vertebrates, the vestibular sensory epithelia appear seemingly more conserved. An exploration of the current knowledge of the comparative biology of the amniote utricle, a vestibular sensory epithelium that senses linear acceleration, shows interesting instances of variability between birds and mammals. The distribution of sensory hair cell types, the position of the line of hair bundle polarity reversal and the properties of supporting cells show marked differences, likely impacting vestibular function and hair cell regeneration potential.
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Affiliation(s)
- Marcela Lipovsek
- Ear Institute, Faculty of Brain Sciences, University College London, London, UK.
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2
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Gao J, Skidmore JM, Cimerman J, Ritter KE, Qiu J, Wilson LMQ, Raphael Y, Kwan KY, Martin DM. CHD7 and SOX2 act in a common gene regulatory network during mammalian semicircular canal and cochlear development. Proc Natl Acad Sci U S A 2024; 121:e2311720121. [PMID: 38408234 DOI: 10.1073/pnas.2311720121] [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: 07/29/2023] [Accepted: 01/19/2024] [Indexed: 02/28/2024] Open
Abstract
Inner ear morphogenesis requires tightly regulated epigenetic and transcriptional control of gene expression. CHD7, an ATP-dependent chromodomain helicase DNA-binding protein, and SOX2, an SRY-related HMG box pioneer transcription factor, are known to contribute to vestibular and auditory system development, but their genetic interactions in the ear have not been explored. Here, we analyzed inner ear development and the transcriptional regulatory landscapes in mice with variable dosages of Chd7 and/or Sox2. We show that combined haploinsufficiency for Chd7 and Sox2 results in reduced otic cell proliferation, severe malformations of semicircular canals, and shortened cochleae with ectopic hair cells. Examination of mice with conditional, inducible Chd7 loss by Sox2CreER reveals a critical period (~E9.5) of susceptibility in the inner ear to combined Chd7 and Sox2 loss. Data from genome-wide RNA-sequencing and CUT&Tag studies in the otocyst show that CHD7 regulates Sox2 expression and acts early in a gene regulatory network to control expression of key otic patterning genes, including Pax2 and Otx2. CHD7 and SOX2 directly bind independently and cooperatively at transcription start sites and enhancers to regulate otic progenitor cell gene expression. Together, our findings reveal essential roles for Chd7 and Sox2 in early inner ear development and may be applicable for syndromic and other forms of hearing or balance disorders.
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Affiliation(s)
- Jingxia Gao
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI 48109
| | | | - Jelka Cimerman
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI 48109
| | - K Elaine Ritter
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI 48109
| | - Jingyun Qiu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
- Keck Center for Collaborative Neuroscience, Stem Cell Research Center, Rutgers University, Piscataway, NJ 08854
| | - Lindsey M Q Wilson
- Medical Scientist Training Program, The University of Michigan, Ann Arbor, MI 48109
| | - Yehoash Raphael
- Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI 48109
| | - Kelvin Y Kwan
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854
- Keck Center for Collaborative Neuroscience, Stem Cell Research Center, Rutgers University, Piscataway, NJ 08854
| | - Donna M Martin
- Department of Pediatrics, The University of Michigan, Ann Arbor, MI 48109
- Department of Human Genetics, The University of Michigan, Ann Arbor, MI 48109
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3
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Xu M, Li S, Xie X, Guo L, Yu D, Zhuo J, Lin J, Kol L, Gan L. ISL1 and POU4F1 Directly Interact to Regulate the Differentiation and Survival of Inner Ear Sensory Neurons. J Neurosci 2024; 44:e1718232024. [PMID: 38267260 PMCID: PMC10883659 DOI: 10.1523/jneurosci.1718-23.2024] [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: 09/12/2023] [Revised: 01/05/2024] [Accepted: 01/11/2024] [Indexed: 01/26/2024] Open
Abstract
The inner ear sensory neurons play a pivotal role in auditory processing and balance control. Though significant progresses have been made, the underlying mechanisms controlling the differentiation and survival of the inner ear sensory neurons remain largely unknown. During development, ISL1 and POU4F transcription factors are co-expressed and are required for terminal differentiation, pathfinding, axon outgrowth and the survival of neurons in the central and peripheral nervous systems. However, little is understood about their functional relationship and regulatory mechanism in neural development. Here, we have knocked out Isl1 or Pou4f1 or both in mice of both sexes. In the absence of Isl1, the differentiation of cochleovestibular ganglion (CVG) neurons is disturbed and with that Isl1-deficient CVG neurons display defects in migration and axon pathfinding. Compound deletion of Isl1 and Pou4f1 causes a delay in CVG differentiation and results in a more severe CVG defect with a loss of nearly all of spiral ganglion neurons (SGNs). Moreover, ISL1 and POU4F1 interact directly in developing CVG neurons and act cooperatively as well as independently in regulating the expression of unique sets of CVG-specific genes crucial for CVG development and survival by binding to the cis-regulatory elements including the promoters of Fgf10, Pou4f2, and Epha5 and enhancers of Eya1 and Ntng2 These findings demonstrate that Isl1 and Pou4f1 are indispensable for CVG development and maintenance by acting epistatically to regulate genes essential for CVG development.
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Affiliation(s)
- Mei Xu
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
- Institution of Life Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Shuchun Li
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
| | - Xiaoling Xie
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
| | - Luming Guo
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
- Institution of Life Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Dongliang Yu
- College of Life Science and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Jiaping Zhuo
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
| | - Jacey Lin
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
| | - Lotem Kol
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
| | - Lin Gan
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, Georgia 30912
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Georgia 30912
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4
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Fang Q, Wei Y, Zhang Y, Cao W, Yan L, Kong M, Zhu Y, Xu Y, Guo L, Zhang L, Wang W, Yu Y, Sun J, Yang J. Stem cells as potential therapeutics for hearing loss. Front Neurosci 2023; 17:1259889. [PMID: 37746148 PMCID: PMC10512725 DOI: 10.3389/fnins.2023.1259889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023] Open
Abstract
Hearing impairment is a global health problem. Stem cell therapy has become a cutting-edge approach to tissue regeneration. In this review, the recent advances in stem cell therapy for hearing loss have been discussed. Nanomaterials can modulate the stem cell microenvironment to augment the therapeutic effects further. The potential of combining nanomaterials with stem cells for repairing and regenerating damaged inner ear hair cells (HCs) and spiral ganglion neurons (SGNs) has also been discussed. Stem cell-derived exosomes can contribute to the repair and regeneration of damaged tissue, and the research progress on exosome-based hearing loss treatment has been summarized as well. Despite stem cell therapy's technical and practical limitations, the findings reported so far are promising and warrant further investigation for eventual clinical translation.
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Affiliation(s)
- Qiaojun Fang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
- School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Yongjie Wei
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yuhua Zhang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Wei Cao
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Lin Yan
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Mengdie Kong
- School of Life Sciences and Technology, Southeast University, Nanjing, China
| | - Yongjun Zhu
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yan Xu
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Lingna Guo
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Lei Zhang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Weiqing Wang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Yafeng Yu
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Jingwu Sun
- Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Jianming Yang
- Department of Otolaryngology-Head and Neck Surgery, the Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
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5
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Wang X, Llamas J, Trecek T, Shi T, Tao L, Makmura W, Crump JG, Segil N, Gnedeva K. SoxC transcription factors shape the epigenetic landscape to establish competence for sensory differentiation in the mammalian organ of Corti. Proc Natl Acad Sci U S A 2023; 120:e2301301120. [PMID: 37585469 PMCID: PMC10450657 DOI: 10.1073/pnas.2301301120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 06/28/2023] [Indexed: 08/18/2023] Open
Abstract
The auditory organ of Corti is comprised of only two major cell types-the mechanosensory hair cells and their associated supporting cells-both specified from a single pool of prosensory progenitors in the cochlear duct. Here, we show that competence to respond to Atoh1, a transcriptional master regulator necessary and sufficient for induction of mechanosensory hair cells, is established in the prosensory progenitors between E12.0 and 13.5. The transition to the competent state is rapid and is associated with extensive remodeling of the epigenetic landscape controlled by the SoxC group of transcription factors. Conditional loss of Sox4 and Sox11-the two homologous family members transiently expressed in the inner ear at the time of competence establishment-blocks the ability of prosensory progenitors to differentiate as hair cells. Mechanistically, we show that Sox4 binds to and establishes accessibility of early sensory lineage-specific regulatory elements, including ones associated with Atoh1 and its direct downstream targets. Consistent with these observations, overexpression of Sox4 or Sox11 prior to developmental establishment of competence precociously induces hair cell differentiation in the cochlear progenitors. Further, reintroducing Sox4 or Sox11 expression restores the ability of postnatal supporting cells to differentiate as hair cells in vitro and in vivo. Our findings demonstrate the pivotal role of SoxC family members as agents of epigenetic and transcriptional changes necessary for establishing competence for sensory receptor differentiation in the inner ear.
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Affiliation(s)
- Xizi Wang
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Juan Llamas
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Talon Trecek
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Tuo Shi
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Litao Tao
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Welly Makmura
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - J. Gage Crump
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Neil Segil
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
| | - Ksenia Gnedeva
- Caruso Department of Otolaryngology–Head and Neck Surgery, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of University of Southern California, Los Angeles, CA90033
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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. 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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7
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Thompson MJ, Young CA, Munnamalai V, Umulis DM. Early radial positional information in the cochlea is optimized by a precise linear BMP gradient and enhanced by SOX2. Sci Rep 2023; 13:8567. [PMID: 37237002 PMCID: PMC10219982 DOI: 10.1038/s41598-023-34725-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Positional information encoded in signaling molecules is essential for early patterning in the prosensory domain of the developing cochlea. The sensory epithelium, the organ of Corti, contains an exquisite repeating pattern of hair cells and supporting cells. This requires precision in the morphogen signals that set the initial radial compartment boundaries, but this has not been investigated. To measure gradient formation and morphogenetic precision in developing cochlea, we developed a quantitative image analysis procedure measuring SOX2 and pSMAD1/5/9 profiles in mouse embryos at embryonic day (E)12.5, E13.5, and E14.5. Intriguingly, we found that the pSMAD1/5/9 profile forms a linear gradient up to the medial ~ 75% of the PSD from the pSMAD1/5/9 peak in the lateral edge during E12.5 and E13.5. This is a surprising activity readout for a diffusive BMP4 ligand secreted from a tightly constrained lateral region since morphogens typically form exponential or power-law gradient shapes. This is meaningful for gradient interpretation because while linear profiles offer the theoretically highest information content and distributed precision for patterning, a linear morphogen gradient has not yet been observed. Furthermore, this is unique to the cochlear epithelium as the pSMAD1/5/9 gradient is exponential in the surrounding mesenchyme. In addition to the information-optimized linear profile, we found that while pSMAD1/5/9 is stable during this timeframe, an accompanying gradient of SOX2 shifts dynamically. Last, through joint decoding maps of pSMAD1/5/9 and SOX2, we see that there is a high-fidelity mapping between signaling activity and position in the regions that will become Kölliker's organ and the organ of Corti. Mapping is ambiguous in the prosensory domain precursory to the outer sulcus. Altogether, this research provides new insights into the precision of early morphogenetic patterning cues in the radial cochlea prosensory domain.
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Affiliation(s)
- Matthew J Thompson
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA
| | - Caryl A Young
- University of Maine, 168 College Ave, Orono, ME, 04469, USA
| | - Vidhya Munnamalai
- University of Maine, 168 College Ave, Orono, ME, 04469, USA.
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA.
| | - David M Umulis
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA.
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8
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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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9
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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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10
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Nie J, Ueda Y, Solivais AJ, Hashino E. CHD7 regulates otic lineage specification and hair cell differentiation in human inner ear organoids. Nat Commun 2022; 13:7053. [PMID: 36396635 PMCID: PMC9672366 DOI: 10.1038/s41467-022-34759-8] [Citation(s) in RCA: 13] [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: 12/01/2021] [Accepted: 11/07/2022] [Indexed: 11/19/2022] Open
Abstract
Mutations in CHD7 cause CHARGE syndrome, affecting multiple organs including the inner ear in humans. We investigate how CHD7 mutations affect inner ear development using human pluripotent stem cell-derived organoids as a model system. We find that loss of CHD7 or its chromatin remodeling activity leads to complete absence of hair cells and supporting cells, which can be explained by dysregulation of key otic development-associated genes in mutant otic progenitors. Further analysis of the mutant otic progenitors suggests that CHD7 can regulate otic genes through a chromatin remodeling-independent mechanism. Results from transcriptome profiling of hair cells reveal disruption of deafness gene expression as a potential underlying mechanism of CHARGE-associated sensorineural hearing loss. Notably, co-differentiating CHD7 knockout and wild-type cells in chimeric organoids partially rescues mutant phenotypes by restoring otherwise severely dysregulated otic genes. Taken together, our results suggest that CHD7 plays a critical role in regulating human otic lineage specification and hair cell differentiation.
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Affiliation(s)
- Jing Nie
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Yoshitomo Ueda
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Alexander J Solivais
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Eri Hashino
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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11
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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: 5] [Impact Index Per Article: 1.7] [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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12
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Smith-Cortinez N, Yadak R, Hendriksen FGJ, Sanders E, Ramekers D, Stokroos RJ, Versnel H, Straatman LV. LGR5-Positive Supporting Cells Survive Ototoxic Trauma in the Adult Mouse Cochlea. Front Mol Neurosci 2021; 14:729625. [PMID: 34675775 PMCID: PMC8523910 DOI: 10.3389/fnmol.2021.729625] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
Sensorineural hearing loss is mainly caused by irreversible damage to sensory hair cells (HCs). A subgroup of supporting cells (SCs) in the cochlea express leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5), a marker for tissue-resident stem cells. LGR5+ SCs could be used as an endogenous source of stem cells for regeneration of HCs to treat hearing loss. Here, we report long-term presence of LGR5+ SCs in the mature adult cochlea and survival of LGR5+ SCs after severe ototoxic trauma characterized by partial loss of inner HCs and complete loss of outer HCs. Surviving LGR5+ SCs (confirmed by GFP expression) were located in the third row of Deiters' cells. We observed a change in the intracellular localization of GFP, from the nucleus in normal-hearing to cytoplasm and membrane in deafened mice. These data suggests that the adult mammalian cochlea possesses properties essential for regeneration even after severe ototoxic trauma.
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Affiliation(s)
- Natalia Smith-Cortinez
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands.,UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Rana Yadak
- Department of Otorhinolaryngology and Head & 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 and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Eefje Sanders
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands
| | - Dyan Ramekers
- Department of Otorhinolaryngology and Head & 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 and Head & 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 and Head & 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 and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, Netherlands.,UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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13
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Kwan KY, White PM. Understanding the differentiation and epigenetics of cochlear sensory progenitors in pursuit of regeneration. Curr Opin Otolaryngol Head Neck Surg 2021; 29:366-372. [PMID: 34374667 PMCID: PMC8452321 DOI: 10.1097/moo.0000000000000741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE OF REVIEW Sensory hair cells (HCs) of the inner ear are responsible for our ability to hear and balance. Loss of these cells results in hearing loss. Stem cell replacement and in situ regeneration have the potential to replace lost HCs. Newly discovered contributions of transcription factor regulatory networks and epigenetic mechanisms in regulating HC differentiation and regeneration are placed into context of the literature. RECENT FINDINGS A wealth of new data has helped to define cochlear sensory progenitors in their developmental trajectories. This includes transcription factor networks, epigenetic manipulations, and cochlear HC subtype specification. SUMMARY Understanding how sensory progenitors differ and how HC subtypes arise will substantially inform efforts in hearing restoration.
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Affiliation(s)
- Kelvin Y. Kwan
- Department of Cell Biology & Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Patricia M. White
- Department of Neuroscience, Ernest J. Del Monte Institute of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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14
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Elliott KL, Pavlinkova G, Chizhikov VV, Yamoah EN, Fritzsch B. Neurog1, Neurod1, and Atoh1 are essential for spiral ganglia, cochlear nuclei, and cochlear hair cell development. Fac Rev 2021; 10:47. [PMID: 34131657 PMCID: PMC8170689 DOI: 10.12703/r/10-47] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We review the molecular basis of three related basic helix–loop–helix (bHLH) genes (Neurog1, Neurod1, and Atoh1) and upstream regulators Eya1/Six1, Sox2, Pax2, Gata3, Fgfr2b, Foxg1, and Lmx1a/b during the development of spiral ganglia, cochlear nuclei, and cochlear hair cells. Neuronal development requires early expression of Neurog1, followed by its downstream target Neurod1, which downregulates Atoh1 expression. In contrast, hair cells and cochlear nuclei critically depend on Atoh1 and require Neurod1 and Neurog1 expression for various aspects of development. Several experiments show a partial uncoupling of Atoh1/Neurod1 (spiral ganglia and cochlea) and Atoh1/Neurog1/Neurod1 (cochlear nuclei). In this review, we integrate the cellular and molecular mechanisms that regulate the development of auditory system and provide novel insights into the restoration of hearing loss, beyond the limited generation of lost sensory neurons and hair cells.
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Affiliation(s)
- Karen L Elliott
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Gabriela Pavlinkova
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czechia
| | - Victor V Chizhikov
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, USA
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15
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Elliott KL, Pavlínková G, Chizhikov VV, Yamoah EN, Fritzsch B. Development in the Mammalian Auditory System Depends on Transcription Factors. Int J Mol Sci 2021; 22:ijms22084189. [PMID: 33919542 PMCID: PMC8074135 DOI: 10.3390/ijms22084189] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022] Open
Abstract
We review the molecular basis of several transcription factors (Eya1, Sox2), including the three related genes coding basic helix–loop–helix (bHLH; see abbreviations) proteins (Neurog1, Neurod1, Atoh1) during the development of spiral ganglia, cochlear nuclei, and cochlear hair cells. Neuronal development requires Neurog1, followed by its downstream target Neurod1, to cross-regulate Atoh1 expression. In contrast, hair cells and cochlear nuclei critically depend on Atoh1 and require Neurod1 expression for interactions with Atoh1. Upregulation of Atoh1 following Neurod1 loss changes some vestibular neurons’ fate into “hair cells”, highlighting the significant interplay between the bHLH genes. Further work showed that replacing Atoh1 by Neurog1 rescues some hair cells from complete absence observed in Atoh1 null mutants, suggesting that bHLH genes can partially replace one another. The inhibition of Atoh1 by Neurod1 is essential for proper neuronal cell fate, and in the absence of Neurod1, Atoh1 is upregulated, resulting in the formation of “intraganglionic” HCs. Additional genes, such as Eya1/Six1, Sox2, Pax2, Gata3, Fgfr2b, Foxg1, and Lmx1a/b, play a role in the auditory system. Finally, both Lmx1a and Lmx1b genes are essential for the cochlear organ of Corti, spiral ganglion neuron, and cochlear nuclei formation. We integrate the mammalian auditory system development to provide comprehensive insights beyond the limited perception driven by singular investigations of cochlear neurons, cochlear hair cells, and cochlear nuclei. A detailed analysis of gene expression is needed to understand better how upstream regulators facilitate gene interactions and mammalian auditory system development.
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Affiliation(s)
- Karen L. Elliott
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA;
| | - Gabriela Pavlínková
- Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czechia;
| | - Victor V. Chizhikov
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA;
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV 89557, USA;
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA;
- Correspondence:
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16
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Hearing Loss Caused by HCMV Infection through Regulating the Wnt and Notch Signaling Pathways. Viruses 2021; 13:v13040623. [PMID: 33917368 PMCID: PMC8067389 DOI: 10.3390/v13040623] [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: 02/16/2021] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 01/27/2023] Open
Abstract
Hearing loss is one of the most prevalent sensory disabilities worldwide with huge social and economic burdens. The leading cause of sensorineural hearing loss (SNHL) in children is congenital cytomegalovirus (CMV) infection. Though the implementation of universal screening and early intervention such as antiviral or anti-inflammatory ameliorate the severity of CMV-associated diseases, direct and targeted therapeutics is still seriously lacking. The major hurdle for it is that the mechanism of CMV induced SNHL has not yet been well understood. In this review, we focus on the impact of CMV infection on the key players in inner ear development including the Wnt and Notch signaling pathways. Investigations on these interactions may gain new insights into viral pathogenesis and reveal novel targets for therapy.
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17
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Żak M, Daudet N. A gradient of Wnt activity positions the neurosensory domains of the inner ear. eLife 2021; 10:59540. [PMID: 33704062 PMCID: PMC7993990 DOI: 10.7554/elife.59540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 03/09/2021] [Indexed: 12/25/2022] Open
Abstract
The auditory and vestibular organs of the inner ear and the neurons that innervate them originate from Sox2-positive and Notch-active neurosensory domains specified at early stages of otic development. Sox2 is initially present throughout the otic placode and otocyst, and then it becomes progressively restricted to a ventro-medial domain. Using gain- and loss-of-function approaches in the chicken otocyst, we show that these early changes in Sox2 expression are regulated in a dose-dependent manner by Wnt/beta-catenin signalling. Both high and very low levels of Wnt activity repress Sox2 and neurosensory competence. However, intermediate levels allow the maintenance of Sox2 expression and sensory organ formation. We propose that a dorso-ventral (high-to-low) gradient and wave of Wnt activity initiated at the dorsal rim of the otic placode progressively restricts Sox2 and Notch activity to the ventral half of the otocyst, thereby positioning the neurosensory competent domains in the inner ear.
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Affiliation(s)
- Magdalena Żak
- UCL Ear Institute, University College London, London, United Kingdom
| | - Nicolas Daudet
- UCL Ear Institute, University College London, London, United Kingdom
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18
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Wang G, Li C, He S, Liu Z. Mosaic CRISPR-stop enables rapid phenotyping of nonsense mutations in essential genes. Development 2021; 148:dev196899. [PMID: 33558388 DOI: 10.1242/dev.196899] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 01/29/2021] [Indexed: 12/25/2022]
Abstract
CRISPR-stop converts protein-coding sequences into stop codons, which, in the appropriate location, results in a null allele. CRISPR-stop induction in one-cell-stage zygotes generates Founder 0 (F0) mice that are homozygous mutants; this avoids mouse breeding and serves as a rapid screening approach for nonlethal genes. However, loss of function of 25% of mammalian genes causes early lethality. Here, we induced CRISPR-stop in one of the two blastomeres of the zygote, a method we name mosaic CRISPR-stop, to produce mosaic Atoh1 and Sox10 F0 mice; these mice not only survived longer than regular Atoh1/Sox10 knockout mice but also displayed their recognized cochlear phenotypes. Moreover, by using mosaic CRISPR-stop, we uncovered a previously unknown role of another lethal gene, Rbm24, in the survival of cochlear outer hair cells (OHCs), and we further validated the importance of Rbm24 in OHCs by using our Rbm24 conditional knockout model. Together, our results demonstrated that mosaic CRISPR-stop is reliable and rapid, and we believe this method will facilitate rapid genetic screening of developmentally lethal genes in the mouse inner ear and also in other organs.
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MESH Headings
- Animals
- Basic Helix-Loop-Helix Transcription Factors/deficiency
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Blastomeres/cytology
- Blastomeres/metabolism
- CRISPR-Cas Systems/genetics
- Codon, Nonsense
- Codon, Terminator
- Genes, Essential/genetics
- Hair Cells, Auditory, Outer/cytology
- Hair Cells, Auditory, Outer/metabolism
- Mice
- Mice, Knockout
- RNA, Guide, CRISPR-Cas Systems/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- SOXE Transcription Factors/deficiency
- SOXE Transcription Factors/genetics
- Zygote/cytology
- Zygote/metabolism
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Affiliation(s)
- Guangqin Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chao Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Shunji He
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhiyong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China
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19
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Steevens AR, Griesbach MW, You Y, Dutton JR, Low WC, Santi PA. Generation of inner ear sensory neurons using blastocyst complementation in a Neurog1 +/--deficient mouse. Stem Cell Res Ther 2021; 12:122. [PMID: 33579352 PMCID: PMC7881691 DOI: 10.1186/s13287-021-02184-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 01/24/2021] [Indexed: 11/10/2022] Open
Abstract
This research is the first to produce induced pluripotent stem cell-derived inner ear sensory neurons in the Neurog1+/− heterozygote mouse using blastocyst complementation. Additionally, this approach corrected non-sensory deficits associated with Neurog1 heterozygosity, indicating that complementation is specific to endogenous Neurog1 function. This work validates the use of blastocyst complementation as a tool to create novel insight into the function of developmental genes and highlights blastocyst complementation as a potential platform for generating chimeric inner ear cell types that can be transplanted into damaged inner ears to improve hearing.
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Affiliation(s)
- Aleta R Steevens
- Department of Ophthalmology, University of Minnesota, Minneapolis, MN, USA. .,Department of Neurosurgery, University of Minnesota, Minneapolis, MN, USA. .,Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA.
| | | | - Yun You
- Mouse Genetics Laboratory, University of Minnesota, Minneapolis, MN, USA
| | - James R Dutton
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA
| | - Walter C Low
- Department of Neurosurgery, University of Minnesota, Minneapolis, MN, USA.,Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA
| | - Peter A Santi
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, USA.,Department of Otolaryngology, University of Minnesota, Minneapolis, MN, USA
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20
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Pavlinkova G. Molecular Aspects of the Development and Function of Auditory Neurons. Int J Mol Sci 2020; 22:ijms22010131. [PMID: 33374462 PMCID: PMC7796308 DOI: 10.3390/ijms22010131] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 01/08/2023] Open
Abstract
This review provides an up-to-date source of information on the primary auditory neurons or spiral ganglion neurons in the cochlea. These neurons transmit auditory information in the form of electric signals from sensory hair cells to the first auditory nuclei of the brain stem, the cochlear nuclei. Congenital and acquired neurosensory hearing loss affects millions of people worldwide. An increasing body of evidence suggest that the primary auditory neurons degenerate due to noise exposure and aging more readily than sensory cells, and thus, auditory neurons are a primary target for regenerative therapy. A better understanding of the development and function of these neurons is the ultimate goal for long-term maintenance, regeneration, and stem cell replacement therapy. In this review, we provide an overview of the key molecular factors responsible for the function and neurogenesis of the primary auditory neurons, as well as a brief introduction to stem cell research focused on the replacement and generation of auditory neurons.
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Affiliation(s)
- Gabriela Pavlinkova
- BIOCEV, Institute of Biotechnology of the Czech Academy of Sciences, 25250 Vestec, Czech Republic
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21
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White PM. Perspectives on Human Hearing Loss, Cochlear Regeneration, and the Potential for Hearing Restoration Therapies. Brain Sci 2020; 10:brainsci10100756. [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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22
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Holman HA, Wan Y, Rabbitt RD. Developmental GAD2 Expression Reveals Progenitor-like Cells with Calcium Waves in Mammalian Crista Ampullaris. iScience 2020; 23:101407. [PMID: 32771977 PMCID: PMC7415930 DOI: 10.1016/j.isci.2020.101407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/29/2020] [Accepted: 07/21/2020] [Indexed: 01/26/2023] Open
Abstract
Sense of motion, spatial orientation, and balance in vertebrates relies on sensory hair cells in the inner ear vestibular system. Vestibular supporting cells can regenerate hair cells that are lost from aging, ototoxicity, and trauma, although not all factors or specific cell types are known. Here we report a population of GAD2-positive cells in the mouse crista ampullaris and trace GAD2 progenitor-like cells that express pluripotent transcription factors SOX2, PROX1, and CTBP2. GAD2 progenitor-like cells organize into rosettes around a central branched structure in the eminentia cruciatum (EC) herein named the EC plexus. GCaMP5G calcium indicator shows spontaneous and acetylcholine-evoked whole-cell calcium waves in neonatal and adult mice. We present a hypothetical model that outlines the lineage and potential regenerative capacity of GAD2 cells in the mammalian vestibular neuroepithelium.
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Affiliation(s)
- Holly A Holman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | - Yong Wan
- Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Richard D Rabbitt
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA; Graduate Program in Neuroscience, University of Utah, Salt Lake City, UT 84112, USA; Department of Otolaryngology-Head & Neck Surgery, University of Utah, Salt Lake City, UT 84112, USA
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23
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Magariños M, Barajas-Azpeleta R, Varela-Nieto I, R Aburto M. Otic Neurogenesis Is Regulated by TGFβ in a Senescence-Independent Manner. Front Cell Neurosci 2020; 14:217. [PMID: 32973450 PMCID: PMC7461926 DOI: 10.3389/fncel.2020.00217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/18/2020] [Indexed: 01/10/2023] Open
Abstract
Cellular senescence has classically been associated with aging. Intriguingly, recent studies have also unraveled key roles for senescence in embryonic development, regeneration, and reprogramming. Developmental senescence has been reported during embryonic development in different organisms and structures, such as the endolymphatic duct during inner ear development of mammals and birds. However, there is no study addressing the possible role of senescence on otic neurogenesis. TGFβ/SMAD is the best-known pathway linked to the induction of developmentally programmed cell senescence. Here, we studied if TGFβ2 induces cellular senescence during acoustic-vestibular-ganglion (AVG) formation. Using organotypic cultures of AVG, and characterizing different stages of otic neurogenesis in the presence of TGFβ2 and a selective TGF-β receptor type-I inhibitor, we show that TGFβ2 exerts a powerful action in inner ear neurogenesis but, contrary to what we recently observed during endolymphatic duct development, these actions are independent of cellular senescence. We show that TGFβ2 reduces proliferation, and induces differentiation and neuritogenesis of neuroblasts, without altering cell death. Our studies highlight the roles of TGFβ2 and cellular senescence in the precise regulation of cell fate within the developing inner ear and its different cell types, being their mechanisms of action highly cell-type dependent.
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Affiliation(s)
- Marta Magariños
- Institute for Biomedical Research "Alberto Sols" (IIBM), Spanish National Research Council-Autonomous University of Madrid (CSIC-UAM), Madrid, Spain.,Centre for Biomedical Network Research (CIBER) on Rare Diseases (CIBERER), Institute of Health Carlos III, Madrid, Spain.,Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Raquel Barajas-Azpeleta
- Institute for Biomedical Research "Alberto Sols" (IIBM), Spanish National Research Council-Autonomous University of Madrid (CSIC-UAM), Madrid, Spain.,Department of Biology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Isabel Varela-Nieto
- Institute for Biomedical Research "Alberto Sols" (IIBM), Spanish National Research Council-Autonomous University of Madrid (CSIC-UAM), Madrid, Spain.,Centre for Biomedical Network Research (CIBER) on Rare Diseases (CIBERER), Institute of Health Carlos III, Madrid, Spain.,Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
| | - Maria R Aburto
- Institute for Biomedical Research "Alberto Sols" (IIBM), Spanish National Research Council-Autonomous University of Madrid (CSIC-UAM), Madrid, Spain.,APC Microbiome Ireland, University College Cork, Cork, Ireland
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24
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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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25
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Kuwahara A, Lewis AE, Coombes C, Leung FS, Percharde M, Bush JO. Delineating the early transcriptional specification of the mammalian trachea and esophagus. eLife 2020; 9:e55526. [PMID: 32515350 PMCID: PMC7282815 DOI: 10.7554/elife.55526] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/04/2020] [Indexed: 12/11/2022] Open
Abstract
The genome-scale transcriptional programs that specify the mammalian trachea and esophagus are unknown. Though NKX2-1 and SOX2 are hypothesized to be co-repressive master regulators of tracheoesophageal fates, this is untested at a whole transcriptomic scale and their downstream networks remain unidentified. By combining single-cell RNA-sequencing with bulk RNA-sequencing of Nkx2-1 mutants and NKX2-1 ChIP-sequencing in mouse embryos, we delineate the NKX2-1 transcriptional program in tracheoesophageal specification, and discover that the majority of the tracheal and esophageal transcriptome is NKX2-1 independent. To decouple the NKX2-1 transcriptional program from regulation by SOX2, we interrogate the expression of newly-identified tracheal and esophageal markers in Sox2/Nkx2-1 compound mutants. Finally, we discover that NKX2-1 binds directly to Shh and Wnt7b and regulates their expression to control mesenchymal specification to cartilage and smooth muscle, coupling epithelial identity with mesenchymal specification. These findings create a new framework for understanding early tracheoesophageal fate specification at the genome-wide level.
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Affiliation(s)
- Akela Kuwahara
- Program in Craniofacial Biology, University of California San FranciscoSan FranciscoUnited States
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Institute for Human Genetics, University of California San FranciscoSan FranciscoUnited States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San FranciscoSan FranciscoUnited States
- Developmental and Stem Cell Biology Graduate Program, University of California San FranciscoSan FranciscoUnited States
| | - Ace E Lewis
- Program in Craniofacial Biology, University of California San FranciscoSan FranciscoUnited States
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Institute for Human Genetics, University of California San FranciscoSan FranciscoUnited States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San FranciscoSan FranciscoUnited States
| | - Coohleen Coombes
- Program in Craniofacial Biology, University of California San FranciscoSan FranciscoUnited States
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Institute for Human Genetics, University of California San FranciscoSan FranciscoUnited States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San FranciscoSan FranciscoUnited States
- Department of Biology, San Francisco State UniversitySan FranciscoUnited States
| | - Fang-Shiuan Leung
- Program in Craniofacial Biology, University of California San FranciscoSan FranciscoUnited States
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Institute for Human Genetics, University of California San FranciscoSan FranciscoUnited States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San FranciscoSan FranciscoUnited States
| | - Michelle Percharde
- MRC London Institute of Medical Sciences (LMS)LondonUnited Kingdom
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College LondonLondonUnited Kingdom
| | - Jeffrey O Bush
- Program in Craniofacial Biology, University of California San FranciscoSan FranciscoUnited States
- Department of Cell and Tissue Biology, University of California San FranciscoSan FranciscoUnited States
- Institute for Human Genetics, University of California San FranciscoSan FranciscoUnited States
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San FranciscoSan FranciscoUnited States
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26
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Lan Y, Tao Y, Wang Y, Ke J, Yang Q, Liu X, Su B, Wu Y, Lin CP, Zhong G. Recent development of AAV-based gene therapies for inner ear disorders. Gene Ther 2020; 27:329-337. [PMID: 32424232 PMCID: PMC7445886 DOI: 10.1038/s41434-020-0155-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/12/2020] [Accepted: 04/27/2020] [Indexed: 01/07/2023]
Abstract
Gene therapy for auditory diseases is gradually maturing. Recent progress in gene therapy treatments for genetic and acquired hearing loss has demonstrated the feasibility in animal models. However, a number of hurdles, such as lack of safe viral vector with high efficiency and specificity, robust deafness large animal models, translating animal studies to clinic etc., still remain to be solved. It is necessary to overcome these challenges in order to effectively recover auditory function in human patients. Here, we review the progress made in our group, especially our efforts to make more effective and cell type-specific viral vectors for targeting cochlea cells.
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Affiliation(s)
- Yiyang Lan
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yong Tao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200011, China
| | - Yunfeng Wang
- ENT institute and Otorhinolaryngology Department of Eye & ENT Hospital, NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Junzi Ke
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Qiuxiang Yang
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Xiaoyi Liu
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Bing Su
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Yiling Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Chao-Po Lin
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Guisheng Zhong
- iHuman Institute, ShanghaiTech University, Shanghai, 201210, China. .,School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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27
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Using Sox2 to alleviate the hallmarks of age-related hearing loss. Ageing Res Rev 2020; 59:101042. [PMID: 32173536 DOI: 10.1016/j.arr.2020.101042] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/07/2023]
Abstract
Age-related hearing loss (ARHL) is the most prevalent sensory deficit. ARHL reduces the quality of life of the growing population, setting seniors up for the enhanced mental decline. The size of the needy population, the structural deficit, and a likely research strategy for effective treatment of chronic neurosensory hearing in the elderly are needed. Although there has been profound advancement in auditory regenerative research, there remain multiple challenges to restore hearing loss. Thus, additional investigations are required, using novel tools. We propose how the (1) flat epithelium, remaining after the organ of Corti has deteriorated, can be converted to the repaired-sensory epithelium, using Sox2. This will include (2) developing an artificial gene regulatory network transmitted by (3) large viral vectors to the flat epithelium to stimulate remnants of the organ of Corti to restore hair cells. We hope to unite with our proposal toward the common goal, eventually restoring a functional human hearing organ by transforming the flat epithelial cells left after the organ of Corti loss.
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28
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Notch-mediated lateral induction is necessary to maintain vestibular prosensory identity during inner ear development. Dev Biol 2020; 462:74-84. [PMID: 32147304 DOI: 10.1016/j.ydbio.2020.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 01/24/2023]
Abstract
The five vestibular organs of the inner ear derive from patches of prosensory cells that express the transcription factor SOX2 and the Notch ligand JAG1. Previous work suggests that JAG1-mediated Notch signaling is both necessary and sufficient for prosensory formation and that the separation of developing prosensory patches is regulated by LMX1a, which antagonizes Notch signaling. We used an inner ear-specific deletion of the Rbpjκ gene in which Notch signaling is progressively lost from the inner ear to show that Notch signaling, is continuously required for the maintenance of prosensory fate. Loss of Notch signaling in prosensory patches causes them to shrink and ultimately disappear. We show this loss of prosensory fate is not due to cell death, but rather to the conversion of prosensory tissue into non-sensory tissue that expresses LMX1a. Notch signaling is therefore likely to stabilize, rather than induce prosensory fate.
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29
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Brown R, Groves AK. Hear, Hear for Notch: Control of Cell Fates in the Inner Ear by Notch Signaling. Biomolecules 2020; 10:biom10030370. [PMID: 32121147 PMCID: PMC7175228 DOI: 10.3390/biom10030370] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 02/08/2023] Open
Abstract
The vertebrate inner ear is responsible for detecting sound, gravity, and head motion. These mechanical forces are detected by mechanosensitive hair cells, arranged in a series of sensory patches in the vestibular and cochlear regions of the ear. Hair cells form synapses with neurons of the VIIIth cranial ganglion, which convey sound and balance information to the brain. They are surrounded by supporting cells, which nourish and protect the hair cells, and which can serve as a source of stem cells to regenerate hair cells after damage in non-mammalian vertebrates. The Notch signaling pathway plays many roles in the development of the inner ear, from the earliest formation of future inner ear ectoderm on the side of the embryonic head, to regulating the production of supporting cells, hair cells, and the neurons that innervate them. Notch signaling is re-deployed in non-mammalian vertebrates during hair cell regeneration, and attempts have been made to manipulate the Notch pathway to promote hair cell regeneration in mammals. In this review, we summarize the different modes of Notch signaling in inner ear development and regeneration, and describe how they interact with other signaling pathways to orchestrate the fine-grained cellular patterns of the ear.
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Affiliation(s)
- Rogers Brown
- Program in Developmental Biology; Baylor College of Medicine, Houston, TX 77030, USA;
| | - Andrew K. Groves
- Program in Developmental Biology; Baylor College of Medicine, Houston, TX 77030, USA;
- Department of Neuroscience; Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-713-798-8743
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30
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Notch Signalling: The Multitask Manager of Inner Ear Development and Regeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1218:129-157. [DOI: 10.1007/978-3-030-34436-8_8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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31
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Dvorakova M, Macova I, Bohuslavova R, Anderova M, Fritzsch B, Pavlinkova G. Early ear neuronal development, but not olfactory or lens development, can proceed without SOX2. Dev Biol 2020; 457:43-56. [PMID: 31526806 PMCID: PMC6938654 DOI: 10.1016/j.ydbio.2019.09.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 12/25/2022]
Abstract
SOX2 is essential for maintaining neurosensory stem cell properties, although its involvement in the early neurosensory development of cranial placodes remains unclear. To address this, we used Foxg1-Cre to conditionally delete Sox2 during eye, ear, and olfactory placode development. Foxg1-Cre mediated early deletion of Sox2 eradicates all olfactory placode development, and disrupts retinal development and invagination of the lens placode. In contrast to the lens and olfactory placodes, the ear placode invaginates and delaminates NEUROD1 positive neurons. Furthermore, we show that SOX2 is not necessary for early ear neurogenesis, since the early inner ear ganglion is formed with near normal central projections to the hindbrain and peripheral projections to the undifferentiated sensory epithelia of E11.5-12.5 ears. However, later stages of ear neurosensory development, in particular, the late forming auditory system, critically depend on the presence of SOX2. Our data establish distinct differences for SOX2 requirements among placodal sensory organs with similarities between olfactory and lens but not ear placode development, consistent with the unique neurosensory development and molecular properties of the ear.
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Affiliation(s)
| | - Iva Macova
- Institute of Biotechnology CAS, Vestec, Czechia
| | | | | | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, USA.
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32
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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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33
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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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34
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Yang LM, Cheah KSE, Huh SH, Ornitz DM. Sox2 and FGF20 interact to regulate organ of Corti hair cell and supporting cell development in a spatially-graded manner. PLoS Genet 2019; 15:e1008254. [PMID: 31276493 PMCID: PMC6636783 DOI: 10.1371/journal.pgen.1008254] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 07/17/2019] [Accepted: 06/18/2019] [Indexed: 01/24/2023] Open
Abstract
The mouse organ of Corti, housed inside the cochlea, contains hair cells and supporting cells that transduce sound into electrical signals. These cells develop in two main steps: progenitor specification followed by differentiation. Fibroblast Growth Factor (FGF) signaling is important in this developmental pathway, as deletion of FGF receptor 1 (Fgfr1) or its ligand, Fgf20, leads to the loss of hair cells and supporting cells from the organ of Corti. However, whether FGF20-FGFR1 signaling is required during specification or differentiation, and how it interacts with the transcription factor Sox2, also important for hair cell and supporting cell development, has been a topic of debate. Here, we show that while FGF20-FGFR1 signaling functions during progenitor differentiation, FGFR1 has an FGF20-independent, Sox2-dependent role in specification. We also show that a combination of reduction in Sox2 expression and Fgf20 deletion recapitulates the Fgfr1-deletion phenotype. Furthermore, we uncovered a strong genetic interaction between Sox2 and Fgf20, especially in regulating the development of hair cells and supporting cells towards the basal end and the outer compartment of the cochlea. To explain this genetic interaction and its effects on the basal end of the cochlea, we provide evidence that decreased Sox2 expression delays specification, which begins at the apex of the cochlea and progresses towards the base, while Fgf20-deletion results in premature onset of differentiation, which begins near the base of the cochlea and progresses towards the apex. Thereby, Sox2 and Fgf20 interact to ensure that specification occurs before differentiation towards the cochlear base. These findings reveal an intricate developmental program regulating organ of Corti development along the basal-apical axis of the cochlea.
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Affiliation(s)
- Lu M. Yang
- Department of Developmental Biology; Washington University School of Medicine; St. Louis, Missouri, United States of America
| | - Kathryn S. E. Cheah
- School of Biomedical Sciences; The University of Hong Kong; Pokfulam, Hong Kong, China
| | - Sung-Ho Huh
- Department of Developmental Biology; Washington University School of Medicine; St. Louis, Missouri, United States of America
- Holland Regenerative Medicine Program, and the Department of Neurological Sciences; University of Nebraska Medical Center; Omaha, Nebraska, United States of America
- * E-mail: (DMO); (SH)
| | - David M. Ornitz
- Department of Developmental Biology; Washington University School of Medicine; St. Louis, Missouri, United States of America
- * E-mail: (DMO); (SH)
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