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Singh J, Randle MR, Walters BJ, Cox BC. The transcription factor Pou4f3 is essential for the survival of postnatal and adult mouse cochlear hair cells and normal hearing. Front Cell Neurosci 2024; 18:1369282. [PMID: 38566840 PMCID: PMC10985149 DOI: 10.3389/fncel.2024.1369282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 02/26/2024] [Indexed: 04/04/2024] Open
Abstract
Introduction Hair cells (HCs) of the cochlea are responsible for sound transduction and hearing perception in mammals. Genetic mutations in the transcription factor Pou4f3 cause non-syndromic autosomal dominant hearing loss in humans (DFNA15) which varies in the age of onset depending on the individual mutation. Mouse models with germline deletion or mutations in Pou4f3 have previously demonstrated its critical role in the maturation and survival of cochlear HCs during embryonic development. However, the role of Pou4f3 in auditory function and in the survival or maintenance of cochlear HCs after birth and during adulthood has not been studied. Methods Therefore, using the inducible CreER-loxP system, we deleted Pou4f3 from mouse cochlear HCs at different postnatal ages, relevant to specific stages of HC maturation and hearing function. Results and discussion Elevated auditory brainstem response thresholds and significant HC loss were detected in mice with Pou4f3 deletion compared to their control littermates, regardless of the age when Pou4f3 was deleted. However, HC loss occurred more rapidly when Pou4f3 was deleted from immature HCs. Additionally, HC loss caused by Pou4f3 deletion did not affect the number of cochlear supporting cells, but caused a delayed loss of spiral ganglion neurons at 4 months after the deletion. In conclusion, Pou4f3 is necessary for the survival of cochlear HCs and normal hearing at all postnatal ages regardless of their maturation state. Our data also suggest that Pou4f3 indirectly regulates the survival of spiral ganglion neurons.
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Affiliation(s)
- Jarnail Singh
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Michelle R. Randle
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Bradley J. Walters
- Department of Otolaryngology-Head and Neck Surgery, University of Mississippi Medical Center, Jackson, MS, United States
| | - Brandon C. Cox
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL, United States
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2
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Choi SW, Abitbol JM, Cheng AG. Hair Cell Regeneration: From Animals to Humans. Clin Exp Otorhinolaryngol 2024; 17:1-14. [PMID: 38271988 PMCID: PMC10933805 DOI: 10.21053/ceo.2023.01382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 01/07/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
Cochlear hair cells convert sound into electrical signals that are relayed via the spiral ganglion neurons to the central auditory pathway. Hair cells are vulnerable to damage caused by excessive noise, aging, and ototoxic agents. Non-mammals can regenerate lost hair cells by mitotic regeneration and direct transdifferentiation of surrounding supporting cells. However, in mature mammals, damaged hair cells are not replaced, resulting in permanent hearing loss. Recent studies have uncovered mechanisms by which sensory organs in non-mammals and the neonatal mammalian cochlea regenerate hair cells, and outlined possible mechanisms why this ability declines rapidly with age in mammals. Here, we review similarities and differences between avian, zebrafish, and mammalian hair cell regeneration. Moreover, we discuss advances and limitations of hair cell regeneration in the mature cochlea and their potential applications to human hearing loss.
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Affiliation(s)
- Sung-Won Choi
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
- Department of Otorhinolaryngology-Head and Neck Surgery and Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
- Department of Otorhinolaryngology-Head and Neck Surgery, Pusan National University School of Medicine, Busan, Korea
| | - Julia M. Abitbol
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
| | - Alan G. Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
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3
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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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4
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Brown AD, Hayward T, Portfors CV, Coffin AB. On the value of diverse organisms in auditory research: From fish to flies to humans. Hear Res 2023; 432:108754. [PMID: 37054531 PMCID: PMC10424633 DOI: 10.1016/j.heares.2023.108754] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/28/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023]
Abstract
Historically, diverse organisms have contributed to our understanding of auditory function. In recent years, the laboratory mouse has become the prevailing non-human model in auditory research, particularly for biomedical studies. There are many questions in auditory research for which the mouse is the most appropriate (or the only) model system available. But mice cannot provide answers for all auditory problems of basic and applied importance, nor can any single model system provide a synthetic understanding of the diverse solutions that have evolved to facilitate effective detection and use of acoustic information. In this review, spurred by trends in funding and publishing and inspired by parallel observations in other domains of neuroscience, we highlight a few examples of the profound impact and lasting benefits of comparative and basic organismal research in the auditory system. We begin with the serendipitous discovery of hair cell regeneration in non-mammalian vertebrates, a finding that has fueled an ongoing search for pathways to hearing restoration in humans. We then turn to the problem of sound source localization - a fundamental task that most auditory systems have been compelled to solve despite large variation in the magnitudes and kinds of spatial acoustic cues available, begetting varied direction-detecting mechanisms. Finally, we consider the power of work in highly specialized organisms to reveal exceptional solutions to sensory problems - and the diverse returns of deep neuroethological inquiry - via the example of echolocating bats. Throughout, we consider how discoveries made possible by comparative and curiosity-driven organismal research have driven fundamental scientific, biomedical, and technological advances in the auditory field.
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Affiliation(s)
- Andrew D Brown
- Department of Speech and Hearing Sciences, University of Washington, 1417 NE 42nd St, Seattle, WA, 98105 USA; Virginia-Merrill Bloedel Hearing Research Center, University of Washington, 1701 NE Columbia Rd, Seattle, WA, 98195 USA.
| | - Tamasen Hayward
- College of Arts and Sciences, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686 USA
| | - Christine V Portfors
- School of Biological Sciences, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686 USA
| | - Allison B Coffin
- College of Arts and Sciences, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686 USA; School of Biological Sciences, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686 USA; Department of Integrative Physiology and Neuroscience, Washington State University, 14204 NE Salmon Creek Ave, Vancouver, WA 98686 USA.
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5
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Yang Q, Chen C, Li J. Editorial: New insights in molecular pathways in ototoxicity. Front Cell Neurosci 2023; 17:1202490. [PMID: 37213215 PMCID: PMC10196499 DOI: 10.3389/fncel.2023.1202490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 04/19/2023] [Indexed: 05/23/2023] Open
Affiliation(s)
- Qianqian Yang
- Department of Pathology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Chen Chen
- Department of Otolaryngology — Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, United States
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, United States
| | - Jianfeng Li
- Department of Otolaryngology — Head and Neck Surgery, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
- Institute of Eye and ENT, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- *Correspondence: Jianfeng Li
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6
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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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7
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Abstract
It is well established that humans and other mammals are minimally regenerative compared with organisms such as zebrafish, salamander or amphibians. In recent years, however, the identification of regenerative potential in neonatal mouse tissues that normally heal poorly in adults has transformed our understanding of regenerative capacity in mammals. In this Review, we survey the mammalian tissues for which regenerative or improved neonatal healing has been established, including the heart, cochlear hair cells, the brain and spinal cord, and dense connective tissues. We also highlight common and/or tissue-specific mechanisms of neonatal regeneration, which involve cells, signaling pathways, extracellular matrix, immune cells and other factors. The identification of such common features across neonatal tissues may direct therapeutic strategies that will be broadly applicable to multiple adult tissues.
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Affiliation(s)
| | - Alice H. Huang
- Department of Orthopedic Surgery, Columbia University, New York, NY 10032, USA
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8
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Lee MP, Waldhaus J. In vitro and in vivo models: What have we learnt about inner ear regeneration and treatment for hearing loss? Mol Cell Neurosci 2022; 120:103736. [PMID: 35577314 PMCID: PMC9551661 DOI: 10.1016/j.mcn.2022.103736] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 04/29/2022] [Accepted: 05/10/2022] [Indexed: 01/07/2023] Open
Abstract
The sensory cells of the inner ear, called hair cells, do not regenerate spontaneously and therefore, hair cell loss and subsequent hearing loss are permanent in humans. Conversely, functional hair cell regeneration can be observed in non-mammalian vertebrate species like birds and fish. Also, during postnatal development in mice, limited regenerative capacity and the potential to isolate stem cells were reported. Together, these findings spurred the interest of current research aiming to investigate the endogenous regenerative potential in mammals. In this review, we summarize current in vitro based approaches and briefly introduce different in vivo model organisms utilized to study hair cell regeneration. Furthermore, we present an overview of the findings that were made synergistically using both, the in vitro and in vivo based tools.
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Affiliation(s)
- Mary P Lee
- Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Joerg Waldhaus
- Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA.
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9
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Li XJ, Morgan C, Goff LA, Doetzlhofer A. Follistatin promotes LIN28B-mediated supporting cell reprogramming and hair cell regeneration in the murine cochlea. SCIENCE ADVANCES 2022; 8:eabj7651. [PMID: 35148175 PMCID: PMC8836811 DOI: 10.1126/sciadv.abj7651] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 12/18/2021] [Indexed: 05/27/2023]
Abstract
Hair cell (HC) loss within the inner ear cochlea is a leading cause for deafness in humans. Before the onset of hearing, immature supporting cells (SCs) in neonatal mice have some limited capacity for HC regeneration. Here, we show that in organoid culture, transient activation of the progenitor-specific RNA binding protein LIN28B and Activin antagonist follistatin (FST) enhances regenerative competence of maturing/mature cochlear SCs by reprogramming them into progenitor-like cells. Transcriptome profiling and mechanistic studies reveal that LIN28B drives SC reprogramming, while FST is required to counterbalance hyperactivation of transforming growth factor-β-type signaling by LIN28B. Last, we show that LIN28B and FST coactivation enhances spontaneous cochlear HC regeneration in neonatal mice and that LIN28B may be part of an endogenous repair mechanism that primes SCs for HC regeneration. These findings indicate that SC dedifferentiation is critical for HC regeneration and identify LIN28B and FST as main regulators.
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Affiliation(s)
- Xiao-Jun Li
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Charles Morgan
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Loyal A. Goff
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Angelika Doetzlhofer
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Otolaryngology and Center for Hearing and Balance, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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10
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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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11
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Engerer P, Petridou E, Williams PR, Suzuki SC, Yoshimatsu T, Portugues R, Misgeld T, Godinho L. Notch-mediated re-specification of neuronal identity during central nervous system development. Curr Biol 2021; 31:4870-4878.e5. [PMID: 34534440 DOI: 10.1016/j.cub.2021.08.049] [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: 06/20/2020] [Revised: 06/27/2021] [Accepted: 08/18/2021] [Indexed: 11/27/2022]
Abstract
Neuronal identity has long been thought of as immutable, so that once a cell acquires a specific fate, it is maintained for life.1 Studies using the overexpression of potent transcription factors to experimentally reprogram neuronal fate in the mouse neocortex2,3 and retina4,5 have challenged this notion by revealing that post-mitotic neurons can switch their identity. Whether fate reprogramming is part of normal development in the central nervous system (CNS) is unclear. While there are some reports of physiological cell fate reprogramming in invertebrates,6,7 and in the vertebrate peripheral nervous system,8 endogenous fate reprogramming in the vertebrate CNS has not been documented. Here, we demonstrate spontaneous fate re-specification in an interneuron lineage in the zebrafish retina. We show that the visual system homeobox 1 (vsx1)-expressing lineage, which has been associated exclusively with excitatory bipolar cell (BC) interneurons,9-12 also generates inhibitory amacrine cells (ACs). We identify a role for Notch signaling in conferring plasticity to nascent vsx1 BCs, allowing suitable transcription factor programs to re-specify them to an AC fate. Overstimulating Notch signaling enhances this physiological phenotype so that both daughters of a vsx1 progenitor differentiate into ACs and partially differentiated vsx1 BCs can be converted into ACs. Furthermore, this physiological re-specification can be mimicked to allow experimental induction of an entirely distinct fate, that of retinal projection neurons, from the vsx1 lineage. Our observations reveal unanticipated plasticity of cell fate during retinal development.
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Affiliation(s)
- Peter Engerer
- Institute of Neuronal Cell Biology, Technische Universität München, Biedersteiner Strasse 29, 80802 Munich, Germany
| | - Eleni Petridou
- Institute of Neuronal Cell Biology, Technische Universität München, Biedersteiner Strasse 29, 80802 Munich, Germany; Graduate School of Systemic Neurosciences (GSN), Ludwig-Maximilian University of Munich, Großhaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Philip R Williams
- Institute of Neuronal Cell Biology, Technische Universität München, Biedersteiner Strasse 29, 80802 Munich, Germany
| | - Sachihiro C Suzuki
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Takeshi Yoshimatsu
- Department of Biological Structure, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Ruben Portugues
- Institute of Neuroscience, Technische Universität München, Biedersteiner Strasse 29, 80802 Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Feodor-Lynen-Strasse 17, 81377 Munich, Germany
| | - Thomas Misgeld
- Institute of Neuronal Cell Biology, Technische Universität München, Biedersteiner Strasse 29, 80802 Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Strasse 17, 81377 Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Feodor-Lynen-Strasse 17, 81377 Munich, Germany
| | - Leanne Godinho
- Institute of Neuronal Cell Biology, Technische Universität München, Biedersteiner Strasse 29, 80802 Munich, Germany.
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12
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Hu Z, Singh A, Bojrab D, Sim N. Insights into the molecular mechanisms regulating mammalian hair cell regeneration. Curr Opin Otolaryngol Head Neck Surg 2021; 29:400-406. [PMID: 34374666 DOI: 10.1097/moo.0000000000000752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE OF REVIEW To give an overview of recent advances in mammalian auditory hair cell regeneration. RECENT FINDINGS Supporting cells act as progenitors to regenerate hair cells in the prehearing mammalian cochlea but not in the mature cochlea. To overcome this developmental obstacle, manipulation of multiple genes and intracellular pathways has been investigated, which has obtained promising data. This review focuses on recent advances in auditory hair cell regeneration, including synergic gene regulation associated with Atoh1 and Notch signaling, epigenetics, and functional recovery of regenerated hair cells. Co-manipulation of genes critical for hair cell development and cell cycle re-entry, including Atoh1, Isl1, Pou4f3, Gata3, Gfi1, P27kip1, RB, Myc, and Notch-signaling genes, has generated hair cell-like cells in the adult cochlea both in vitro and in vivo. The epigenetic mechanism has been studied in hair cell development and regeneration. Regeneration of hair cell function has a very limited progress, which lacks in-vitro and in-vivo electrophysiology data. SUMMARY Regeneration of adult auditory hair cells remains a major challenge. Manipulation of multiple genes and pathways together with epigenetic regulation might potentially regenerate functional hair cells in the adult mammalian cochlea.
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Affiliation(s)
- Zhengqing Hu
- John D. Dingell VA Medical Center
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| | - Aditi Singh
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
| | - Dennis Bojrab
- Michigan Ear Institute, Farmington Hills, Michigan, USA
| | - Nathan Sim
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit
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13
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Gao J, Fan L, Zhao L, Su Y. The interaction of Notch and Wnt signaling pathways in vertebrate regeneration. CELL REGENERATION (LONDON, ENGLAND) 2021; 10:11. [PMID: 33791915 PMCID: PMC8012441 DOI: 10.1186/s13619-020-00072-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/14/2020] [Indexed: 12/21/2022]
Abstract
Regeneration is an evolutionarily conserved process in animal kingdoms, however, the regenerative capacities differ from species and organ/tissues. Mammals possess very limited regenerative potential to replace damaged organs, whereas non-mammalian species usually have impressive abilities to regenerate organs. The regeneration process requires proper spatiotemporal regulation from key signaling pathways. The canonical Notch and Wnt signaling pathways, two fundamental signals guiding animal development, have been demonstrated to play significant roles in the regeneration of vertebrates. In recent years, increasing evidence has implicated the cross-talking between Notch and Wnt signals during organ regeneration. In this review, we summarize the roles of Notch signaling and Wnt signaling during several representative organ regenerative events, emphasizing the functions and molecular bases of their interplay in these processes, shedding light on utilizing these two signaling pathways to enhance regeneration in mammals and design legitimate therapeutic strategies.
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Affiliation(s)
- Junying Gao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China.,College of Fisheries, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Lixia Fan
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China.,College of Fisheries, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Long Zhao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China. .,College of Fisheries, Ocean University of China, Qingdao, 266003, Shandong, China.
| | - Ying Su
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, Shandong, China. .,College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, Shandong, China.
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14
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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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15
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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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16
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Hoa M, Olszewski R, Li X, Taukulis I, Gu S, DeTorres A, Lopez IA, Linthicum FH, Ishiyama A, Martin D, Morell RJ, Kelley MW. Characterizing Adult Cochlear Supporting Cell Transcriptional Diversity Using Single-Cell RNA-Seq: Validation in the Adult Mouse and Translational Implications for the Adult Human Cochlea. Front Mol Neurosci 2020; 13:13. [PMID: 32116546 PMCID: PMC7012811 DOI: 10.3389/fnmol.2020.00013] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 01/16/2020] [Indexed: 12/11/2022] Open
Abstract
Hearing loss is a problem that impacts a significant proportion of the adult population. Cochlear hair cell (HC) loss due to loud noise, chemotherapy and aging is the major underlying cause. A significant proportion of these individuals are dissatisfied with available treatment options which include hearing aids and cochlear implants. An alternative approach to restore hearing would be to regenerate HCs. Such therapy would require a recapitulation of the complex architecture of the organ of Corti, necessitating regeneration of both mature HCs and supporting cells (SCs). Transcriptional profiles of the mature cell types in the cochlea are necessary to can provide a metric for eventual regeneration therapies. To assist in this effort, we sought to provide the first single-cell characterization of the adult cochlear SC transcriptome. We performed single-cell RNA-Seq on FACS-purified adult cochlear SCs from the LfngEGFP adult mouse, in which SCs express GFP. We demonstrate that adult cochlear SCs are transcriptionally distinct from their perinatal counterparts. We establish cell-type-specific adult cochlear SC transcriptome profiles, and we validate these expression profiles through a combination of both fluorescent immunohistochemistry and in situ hybridization co-localization and quantitative polymerase chain reaction (qPCR) of adult cochlear SCs. Furthermore, we demonstrate the relevance of these profiles to the adult human cochlea through immunofluorescent human temporal bone histopathology. Finally, we demonstrate cell cycle regulator expression in adult SCs and perform pathway analyses to identify potential mechanisms for facilitating mitotic regeneration (cell proliferation, differentiation, and eventually regeneration) in the adult mammalian cochlea. Our findings demonstrate the importance of characterizing mature as opposed to perinatal SCs.
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Affiliation(s)
- Michael Hoa
- Auditory Restoration and Development Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Rafal Olszewski
- Auditory Restoration and Development Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Xiaoyi Li
- Auditory Restoration and Development Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Ian Taukulis
- Auditory Restoration and Development Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Shoujun Gu
- Auditory Restoration and Development Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Alvin DeTorres
- Auditory Restoration and Development Program, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Ivan A Lopez
- National Temporal Bone Laboratory at UCLA, UCLA School of Medicine, Los Angeles, CA, United States.,Cellular and Molecular Biology of the Inner Ear Laboratory, UCLA School of Medicine, Los Angeles, CA, United States
| | - Fred H Linthicum
- National Temporal Bone Laboratory at UCLA, UCLA School of Medicine, Los Angeles, CA, United States.,Cellular and Molecular Biology of the Inner Ear Laboratory, UCLA School of Medicine, Los Angeles, CA, United States
| | - Akira Ishiyama
- National Temporal Bone Laboratory at UCLA, UCLA School of Medicine, Los Angeles, CA, United States.,Cellular and Molecular Biology of the Inner Ear Laboratory, UCLA School of Medicine, Los Angeles, CA, United States
| | - Daniel Martin
- Biomedical Research Informatics Office, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, United States
| | - Robert J Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD, United States
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17
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Cousins RPC. Medicines discovery for auditory disorders: Challenges for industry. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3652. [PMID: 31795652 DOI: 10.1121/1.5132706] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Currently, no approved medicines are available for the prevention or treatment of hearing loss. Pharmaceutical industry productivity across all therapeutic indications has historically been disappointing, with a 90% chance of failure in delivering a marketed drug after entering clinical evaluation. To address these failings, initiatives have been applied in the three cornerstones of medicine discovery: target selection, clinical candidate selection, and clinical studies. These changes aimed to enable data-informed decisions on the translation of preclinical observations into a safe, clinically effective medicine by ensuring the best biological target is selected, the most appropriate chemical entity is advanced, and that the clinical studies enroll the correct patients. The specific underlying pathologies need to be known to allow appropriate patient selection, so improved diagnostics are required, as are methodologies for measuring in the inner ear target engagement, drug delivery and pharmacokinetics. The different therapeutic strategies of protecting hearing or preventing hearing loss versus restoring hearing are reviewed along with potential treatments for tinnitus. Examples of current investigational drugs are discussed to highlight key challenges in drug discovery and the learnings being applied to improve the probability of success of launching a marketed medicine.
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Affiliation(s)
- Rick P C Cousins
- University College London Ear Institute, University College London, London, WC1X 8EE, United Kingdom
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18
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McGovern MM, Randle MR, Cuppini CL, Graves KA, Cox BC. Multiple supporting cell subtypes are capable of spontaneous hair cell regeneration in the neonatal mouse cochlea. Development 2019; 146:146/4/dev171009. [PMID: 30770379 DOI: 10.1242/dev.171009] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 01/09/2019] [Indexed: 12/20/2022]
Abstract
Supporting cells (SCs) are known to spontaneously regenerate hair cells (HCs) in the neonatal mouse cochlea, yet little is known about the relative contribution of distinct SC subtypes which differ in morphology and function. We have previously shown that HC regeneration is linked to Notch signaling, and some SC subtypes, but not others, lose expression of the Notch effector Hes5 Other work has demonstrated that Lgr5-positive SCs have an increased capacity to regenerate HCs; however, several SC subtypes express Lgr5. To further investigate the source for spontaneous HC regeneration, we used three CreER lines to fate-map distinct groups of SCs during regeneration. Fate-mapping either alone or combined with a mitotic tracer showed that pillar and Deiters' cells contributed more regenerated HCs overall. However, when normalized to the total fate-mapped population, pillar, Deiters', inner phalangeal and border cells had equal capacity to regenerate HCs, and all SC subtypes could divide after HC damage. Investigating the mechanisms that allow individual SC subtypes to regenerate HCs and the postnatal changes that occur in each group during maturation could lead to therapies for hearing loss.
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Affiliation(s)
- Melissa M McGovern
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Michelle R Randle
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Candice L Cuppini
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Kaley A Graves
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
| | - Brandon C Cox
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA .,Department of Surgery, Division of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA
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19
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Walters BJ, Cox BC. Approaches for the study of epigenetic modifications in the inner ear and related tissues. Hear Res 2019; 376:69-85. [PMID: 30679030 DOI: 10.1016/j.heares.2019.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/12/2018] [Accepted: 01/11/2019] [Indexed: 12/12/2022]
Abstract
DNA methylation and histone modifications such as methylation, acetylation, and phosphorylation, are two types of epigenetic modifications that alter gene expression. These additions to DNA regulatory elements or to the tails of histones can be inherited or can also occur de novo. Since epigenetic modifications can have significant effects on various processes at both the cellular and organismal level, there has been a rapid increase in research on this topic throughout all fields of biology in recent years. However, epigenetic research is relativity new for the inner ear field, likely due to the limited number of cells present and their quiescent nature. Here, we provide an overview of methods used to detect DNA methylation and histone modifications with a focus on those that have been validated for use with limited cell numbers and a discussion of the strengths and limitations for each. We also provide examples for how these methods have been used to investigate the epigenetic landscape in the inner ear and related tissues.
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Affiliation(s)
- Bradley J Walters
- Departments of Neurobiology and Anatomical Sciences, and of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Brandon C Cox
- Departments of Pharmacology and Surgery, Division of Otolaryngology, Southern Illinois University School of Medicine, Springfield, IL 62711, USA.
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20
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Samadani AA, Norollahi SE, Rashidy-Pour A, Mansour-Ghanaei F, Nemati S, Joukar F, Afshar AM, Ghazanfari S, Safizadeh M, Rostami P, Gatei M. Cancer signaling pathways with a therapeutic approach: An overview in epigenetic regulations of cancer stem cells. Biomed Pharmacother 2018; 108:590-599. [DOI: 10.1016/j.biopha.2018.09.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/08/2018] [Accepted: 09/08/2018] [Indexed: 02/07/2023] Open
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