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Zhang L, Chen X, Wang X, Zhou Y, Fang Y, Gu X, Zhang Z, Sun Q, Li N, Xu L, Tan F, Chai R, Qi J. AAV-mediated Gene Cocktails Enhance Supporting Cell Reprogramming and Hair Cell Regeneration. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2304551. [PMID: 38810137 DOI: 10.1002/advs.202304551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 05/02/2024] [Indexed: 05/31/2024]
Abstract
Mammalian cochlear hair cells (HCs) are essential for hearing, and damage to HCs results in severe hearing impairment. Damaged HCs can be regenerated by neighboring supporting cells (SCs), thus the functional regeneration of HCs is the main goal for the restoration of auditory function in vivo. Here, cochlear SC trans-differentiation into outer and inner HC by the induced expression of the key transcription factors Atoh1 and its co-regulators Gfi1, Pou4f3, and Six1 (GPAS), which are necessary for SCs that are destined for HC development and maturation via the AAV-ie targeting the inner ear stem cells are successfully achieved. Single-cell nuclear sequencing and lineaging tracing results showed that the majority of new Atoh1-derived HCs are in a state of initiating differentiation, while GP (Gfi1, Pou4f3) and GPS (Gfi1, Pou4f3, and Six1) enhanced the Atoh1-induced new HCs into inner and outer HCs. Moreover, the patch-clamp analysis indicated that newborn inner HCs induced by GPAS forced expression have similar electrophysiological characteristics to those of native inner HCs. Also, GPAS can induce HC regeneration in the HC-damaged mice model. In summary, the study demonstrates that AAV-mediated co-regulation of multiple genes, such as GPAS, is an effective means to achieve functional HC regeneration in the mouse cochlea.
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Affiliation(s)
- Liyan Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xin Chen
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xinlin Wang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yinyi Zhou
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Yuan Fang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Xingliang Gu
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Ziyu Zhang
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Qiuhan Sun
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Nianci Li
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Lei Xu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, 250022, China
- Shandong Institute of Otorhinolaryngology, Jinan, 250022, China
| | - Fangzhi Tan
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
| | - Renjie Chai
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
- Department of Neurology, Aerospace Center Hospital, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
- Department of Otolaryngology-Head and Neck Surgery, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610072, China
- Southeast University Shenzhen Research Institute, Shenzhen, 518063, China
| | - Jieyu Qi
- State Key Laboratory of Digital Medical Engineering, Department of Otolaryngology-Head and Neck Surgery, Zhongda Hospital, School of Life Sciences and Technology, School of Medicine, Advanced Institute for Life and Health, Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, 210096, China
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
- Department of Neurology, Aerospace Center Hospital, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
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Cumpata AJ, Labusca L, Radulescu LM. Stem Cell-Based Therapies for Auditory Hair Cell Regeneration in the Treatment of Hearing Loss. TISSUE ENGINEERING. PART B, REVIEWS 2024; 30:15-28. [PMID: 37440318 DOI: 10.1089/ten.teb.2023.0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/15/2023]
Abstract
The incidence and prevalence of hearing loss is increasing globally at an accelerated pace. Hair cells represent the sensory receptors of auditory and vestibular systems. Hair cell absence, loss or degeneration due to congenital diseases, trauma, toxicity, infection or advancing age, results in disabling hearing loss. Regenerative medicine approaches consisting in stem cell-based hair cell rescue or regeneration, gene therapy, as well as cell and tissue engineering are expected to dramatically improve the therapeutic arsenal available for addressing hearing loss. Current strategies that are using different stem cell types to rescue or to induce hair cell proliferation and regeneration are presented. Gene and cell therapy methods that modulates transdifferentiation of surrounding cell types into hair cells are presented, together with their specific advantages and limitations. Several modalities for improving therapeutic targeting to the inner ear such as nanoparticle-mediated cell and gene delivery are introduced. Further steps in building more relevant high-throughput models for testing novel drugs and advanced therapies are proposed as a modality to accelerate translation to clinical settings.
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Affiliation(s)
| | - Luminita Labusca
- Orthopedics and Traumatology Clinic, Emergency Hospital Saint Spiridon, Iasi, Romania
- Magnetic Materials and Sensors, National Institute of Research and Development in Technical Physics, Iasi, Romania
| | - Luminita Mihaela Radulescu
- Doctoral School, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania
- ENT Clinic Department, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania
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Liu Y, Yang L, Singh S, Beyer LA, Prieskorn DM, Swiderski DL, Groves AK, Raphael Y. Combinatorial Atoh1, Gfi1, Pou4f3, and Six1 gene transfer induces hair cell regeneration in the flat epithelium of mature guinea pigs. Hear Res 2024; 441:108916. [PMID: 38103445 DOI: 10.1016/j.heares.2023.108916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/29/2023] [Accepted: 11/14/2023] [Indexed: 12/19/2023]
Abstract
Flat epithelium (FE) is a condition characterized by the loss of both hair cells (HCs) and supporting cells and the transformation of the organ of Corti into a simple flat or cuboidal epithelium, which can occur after severe cochlear insults. The transcription factors Gfi1, Atoh1, Pou4f3, and Six1 (GAPS) play key roles in HC differentiation and survival in normal ears. Previous work using a single transcription factor, Atoh1, to induce HC regeneration in mature ears in vivo usually produced very few cells and failed to produce HCs in severely damaged organs of Corti, especially those with FE. Studies in vitro suggested combinations of transcription factors may be more effective than any single factor, thus the current study aims to examine the effect of co-overexpressing GAPS genes in deafened mature guinea pig cochleae with FE. Deafening was achieved through the infusion of neomycin into the perilymph, leading to the formation of FE and substantial degeneration of nerve fibers. Seven days post neomycin treatment, adenovirus vectors carrying GAPS were injected into the scala media and successfully expressed in the FE. One or two months following GAPS inoculation, cells expressing Myosin VIIa were observed in regions under the FE (located at the scala tympani side of the basilar membrane), rather than within the FE. The number of cells, which we define as induced HCs (iHCs), was not significantly different between one and two months, but the larger N at two months made it more apparent that there were significantly more iHCs in GAPS treated animals than in controls. Additionally, qualitative observations indicated that ears with GAPS gene expression in the FE had more nerve fibers than FE without the treatment. In summary, our results showed that co-overexpression of GAPS enhances the potential for HC regeneration in a severe lesion model of FE.
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Affiliation(s)
- Yujie Liu
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Otolaryngology-Head and Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Ministry of Education Key Laboratory of Otolaryngology-Head and Neck Surgery, Beijing 100730, China
| | - Lin Yang
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Otolaryngology-Head and Neck Surgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China
| | - Sunita Singh
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA
| | - Lisa A Beyer
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Diane M Prieskorn
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI, USA.
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You D, Ni W, Huang Y, Zhou Q, Zhang Y, Jiang T, Chen Y, Li W. The proper timing of Atoh1 expression is pivotal for hair cell subtype differentiation and the establishment of inner ear function. Cell Mol Life Sci 2023; 80:349. [PMID: 37930405 PMCID: PMC10628023 DOI: 10.1007/s00018-023-04947-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 11/07/2023]
Abstract
Atoh1 overexpression is essential for hair cell (HC) regeneration in the sensory epithelium of mammalian auditory and vestibular organs. However, Atoh1 overexpression alone cannot induce fully mature and functional HCs in the mammalian inner ear. In the current study, we investigated the effect of Atoh1 constitutive overexpression in native HCs by manipulating Atoh1 expression at different developmental stages. We demonstrated that constitutive overexpression of Atoh1 in native vestibular HCs did not affect cell survival but did impair vestibular function by interfering with the subtype differentiation of HCs and hair bundle development. In contrast, Atoh1 overexpression in cochlear HCs impeded their maturation, eventually leading to gradual HC loss in the cochlea and hearing dysfunction. Our study suggests that time-restricted Atoh1 expression is essential for the differentiation and survival of HCs in the inner ear, and this is pivotal for both hearing and vestibular function re-establishment through Atoh1 overexpression-induced HC regeneration strategies.
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Affiliation(s)
- Dan You
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Wenli Ni
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Yikang Huang
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Qin Zhou
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Yanping Zhang
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Tao Jiang
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China
| | - Yan Chen
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China.
| | - Wenyan Li
- ENT Institute, Department of Otorhinolaryngology, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, People's Republic of China.
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Kempfle JS, Jung DH. Experimental drugs for the prevention or treatment of sensorineural hearing loss. Expert Opin Investig Drugs 2023; 32:643-654. [PMID: 37598357 DOI: 10.1080/13543784.2023.2242253] [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: 02/15/2023] [Accepted: 07/26/2023] [Indexed: 08/22/2023]
Abstract
INTRODUCTION Sensorineural hearing loss results in irreversible loss of inner ear hair cells and spiral ganglion neurons. Reduced sound detection and speech discrimination can span all ages, and sensorineural hearing rehabilitation is limited to amplification with hearing aids or cochlear implants. Recent insights into experimental drug treatments for inner ear regeneration and otoprotection have paved the way for clinical trials in order to restore a more physiological hearing experience. Paired with the development of innovative minimally invasive approaches for drug delivery to the inner ear, new, emerging treatments for hearing protection and restoration are within reach. AREAS COVERED This expert opinion provides an overview of the latest experimental drug therapies to protect from and to restore sensorineural hearing loss. EXPERT OPINION The degree and type of cellular damage to the cochlea, the responsiveness of remaining, endogenous cells to regenerative treatments, and the duration of drug availability within cochlear fluids will determine the success of hearing protection or restoration.
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Affiliation(s)
- Judith S Kempfle
- Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Otolaryngology, Head & Neck Surgery, Harvard Medical School, Boston, MA, USA
- Department of Otolaryngology, UMass Memorial Medical Center, Worcester, MA, USA
- Department of Otolaryngology, Head & Neck Surgery, University of Massachusetts Medical School, Worcester, MA, USA
| | - David H Jung
- Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Otolaryngology, Head & Neck Surgery, Harvard Medical School, Boston, MA, USA
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Quan YZ, Wei W, Ergin V, Rameshbabu A, Huang M, Tian C, Saladi S, Indzhykulian A, Chen ZY. Reprogramming by drug-like molecules leads to regeneration of cochlear hair cell-like cells in adult mice. Proc Natl Acad Sci U S A 2023; 120:e2215253120. [PMID: 37068229 PMCID: PMC10151514 DOI: 10.1073/pnas.2215253120] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 03/02/2023] [Indexed: 04/19/2023] Open
Abstract
Strategies to overcome irreversible cochlear hair cell (HC) damage and loss in mammals are of vital importance to hearing recovery in patients with permanent hearing loss. In mature mammalian cochlea, co-activation of Myc and Notch1 reprograms supporting cells (SC) and promotes HC regeneration. Understanding of the underlying mechanisms may aid the development of a clinically relevant approach to achieve HC regeneration in the nontransgenic mature cochlea. By single-cell RNAseq, we show that MYC/NICD "rejuvenates" the adult mouse cochlea by activating multiple pathways including Wnt and cyclase activator of cyclic AMP (cAMP), whose blockade suppresses HC-like cell regeneration despite Myc/Notch activation. We screened and identified a combination (the cocktail) of drug-like molecules composing of small molecules and small interfering RNAs to activate the pathways of Myc, Notch1, Wnt and cAMP. We show that the cocktail effectively replaces Myc and Notch1 transgenes and reprograms fully mature wild-type (WT) SCs for HC-like cells regeneration in vitro. Finally, we demonstrate the cocktail is capable of reprogramming adult cochlea for HC-like cells regeneration in WT mice with HC loss in vivo. Our study identifies a strategy by a clinically relevant approach to reprogram mature inner ear for HC-like cells regeneration, laying the foundation for hearing restoration by HC regeneration.
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Affiliation(s)
- Yi-Zhou Quan
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
| | - Wei Wei
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
- Department of Otolaryngology-Head and Necks, Shengjing Hospital of China Medical University, Shenyang110004, China
| | - Volkan Ergin
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
| | - Arun Prabhu Rameshbabu
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
| | - Mingqian Huang
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
| | - Chunjie Tian
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
| | - Srinivas Vinod Saladi
- Broad Institute of MIT and Harvard, Cambridge, MA02142
- Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA02114
| | - Artur A. Indzhykulian
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
| | - Zheng-Yi Chen
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA02115
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Neuroscience, Harvard Medical School, Boston, MA02115
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA02114
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Stepwise fate conversion of supporting cells to sensory hair cells in the chick auditory epithelium. iScience 2023; 26:106046. [PMID: 36818302 PMCID: PMC9932131 DOI: 10.1016/j.isci.2023.106046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 12/17/2022] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
In contrast to mammals, the avian cochlea, specifically the basilar papilla, can regenerate sensory hair cells, which involves fate conversion of supporting cells to hair cells. To determine the mechanisms for converting supporting cells to hair cells, we used single-cell RNA sequencing during hair cell regeneration in explant cultures of chick basilar papillae. We identified dynamic changes in the gene expression of supporting cells, and the pseudotime trajectory analysis demonstrated the stepwise fate conversion from supporting cells to hair cells. Initially, supporting cell identity was erased and transition to the precursor state occurred. A subsequent gain in hair cell identity progressed together with downregulation of precursor-state genes. Transforming growth factor β receptor 1-mediated signaling was involved in induction of the initial step, and its inhibition resulted in suppression of hair cell regeneration. Our data provide new insights for understanding fate conversion from supporting cells to hair cells in avian basilar papillae.
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8
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Wang J, Zheng J, Wang H, He H, Li S, Zhang Y, Wang Y, Xu X, Wang S. Gene therapy: an emerging therapy for hair cells regeneration in the cochlea. Front Neurosci 2023; 17:1177791. [PMID: 37207182 PMCID: PMC10188948 DOI: 10.3389/fnins.2023.1177791] [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: 03/02/2023] [Accepted: 04/12/2023] [Indexed: 05/21/2023] Open
Abstract
Sensorineural hearing loss is typically caused by damage to the cochlear hair cells (HCs) due to external stimuli or because of one's genetic factors and the inability to convert sound mechanical energy into nerve impulses. Adult mammalian cochlear HCs cannot regenerate spontaneously; therefore, this type of deafness is usually considered irreversible. Studies on the developmental mechanisms of HC differentiation have revealed that nonsensory cells in the cochlea acquire the ability to differentiate into HCs after the overexpression of specific genes, such as Atoh1, which makes HC regeneration possible. Gene therapy, through in vitro selection and editing of target genes, transforms exogenous gene fragments into target cells and alters the expression of genes in target cells to activate the corresponding differentiation developmental program in target cells. This review summarizes the genes that have been associated with the growth and development of cochlear HCs in recent years and provides an overview of gene therapy approaches in the field of HC regeneration. It concludes with a discussion of the limitations of the current therapeutic approaches to facilitate the early implementation of this therapy in a clinical setting.
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Affiliation(s)
- Jipeng Wang
- Department of Gastrointestinal Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jianwei Zheng
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haiyan Wang
- Department of Otolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
| | - Haoying He
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
| | - Shuang Li
- Department of Otolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
| | - Ya Zhang
- Department of Otolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
| | - You Wang
- Department of Stomatology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
- *Correspondence: You Wang,
| | - Xiaoxiang Xu
- Department of Otolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
- Xiaoxiang Xu,
| | - Shuyi Wang
- Department of Gastrointestinal Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
- Shuyi Wang,
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9
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Le Prell CG, Brewer CC, Campbell KCM. The audiogram: Detection of pure-tone stimuli in ototoxicity monitoring and assessments of investigational medicines for the inner ear. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:470. [PMID: 35931504 PMCID: PMC9288270 DOI: 10.1121/10.0011739] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/01/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Pure-tone thresholds have long served as a gold standard for evaluating hearing sensitivity and documenting hearing changes related to medical treatments, toxic or otherwise hazardous exposures, ear disease, genetic disorders involving the ear, and deficits that develop during aging. Although the use of pure-tone audiometry is basic and standard, interpretation of thresholds obtained at multiple frequencies in both ears over multiple visits can be complex. Significant additional complexity is introduced when audiometric tests are performed within ototoxicity monitoring programs to determine if hearing loss occurs as an adverse reaction to an investigational medication and during the design and conduct of clinical trials for new otoprotective agents for noise and drug-induced hearing loss. Clinical trials using gene therapy or stem cell therapy approaches are emerging as well with audiometric outcome selection further complicated by safety issues associated with biological therapies. This review addresses factors that must be considered, including test-retest variability, significant threshold change definitions, use of ototoxicity grading scales, interpretation of early warning signals, measurement of notching in noise-induced hearing loss, and application of age-based normative data to interpretation of pure-tone thresholds. Specific guidance for clinical trial protocols that will assure rigorous methodological approaches and interpretable audiometric data are provided.
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Affiliation(s)
- Colleen G Le Prell
- Department of Speech, Language, and Hearing, University of Texas at Dallas, Dallas, Texas 75080, USA
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Washington D.C. 20892, USA
| | - Kathleen C M Campbell
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois 62702, USA
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10
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Lewis RM. From Bench to Booth: Examining Hair-Cell Regeneration Through an Audiologist's Scope. J Am Acad Audiol 2022; 32:654-660. [PMID: 35609592 DOI: 10.1055/s-0041-1731700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Damage to auditory hair cells is a key feature of sensorineural hearing loss due to aging, noise exposure, or ototoxic drugs. Though hair-cell loss is permanent in humans, research in bird species led to the discovery that analogous hair cells of the avian basilar papilla are able to regenerate after being damaged by ototoxic agents. Regeneration appears to occur through a combination of the mitotic expansion of a precursor population of supporting cells and direct transdifferentiation of supporting cells into functioning hair cells. This review will synthesize the relevant anatomy and pathophysiology of sensorineural hearing loss, the historical observations that led to the genesis of the hair-cell regeneration field, and perspectives on initial human hair-cell regeneration trials.
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Affiliation(s)
- Rebecca M Lewis
- Whisper.ai, Department of Clinical Research, San Francisco, California.,Georgetown University Medical Center, Department of Neuroscience, Washington, D.C
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11
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Liu SS, Yang R. Inner Ear Drug Delivery for Sensorineural Hearing Loss: Current Challenges and Opportunities. Front Neurosci 2022; 16:867453. [PMID: 35685768 PMCID: PMC9170894 DOI: 10.3389/fnins.2022.867453] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/02/2022] [Indexed: 12/20/2022] Open
Abstract
Most therapies for treating sensorineural hearing loss are challenged by the delivery across multiple tissue barriers to the hard-to-access anatomical location of the inner ear. In this review, we will provide a recent update on various pharmacotherapy, gene therapy, and cell therapy approaches used in clinical and preclinical studies for the treatment of sensorineural hearing loss and approaches taken to overcome the drug delivery barriers in the ear. Small-molecule drugs for pharmacotherapy can be delivered via systemic or local delivery, where the blood-labyrinth barrier hinders the former and tissue barriers including the tympanic membrane, the round window membrane, and/or the oval window hinder the latter. Meanwhile, gene and cell therapies often require targeted delivery to the cochlea, which is currently achieved via intra-cochlear or intra-labyrinthine injection. To improve the stability of the biomacromolecules during treatment, e.g., RNAs, DNAs, proteins, additional packing vehicles are often required. To address the diverse range of biological barriers involved in inner ear drug delivery, each class of therapy and the intended therapeutic cargoes will be discussed in this review, in the context of delivery routes commonly used, delivery vehicles if required (e.g., viral and non-viral nanocarriers), and other strategies to improve drug permeation and sustained release (e.g., hydrogel, nanocarriers, permeation enhancers, and microfluidic systems). Overall, this review aims to capture the important advancements and key steps in the development of inner ear therapies and delivery strategies over the past two decades for the treatment and prophylaxis of sensorineural hearing loss.
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Affiliation(s)
- Sophie S. Liu
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Rong Yang
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
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12
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Abstract
INTRODUCTION More than 5% of the world's population have a disabling hearing loss which can be managed by hearing aids or implanted electrical devices. However, outcomes are highly variable, and the sound perceived by recipients is far from perfect. Sparked by the discovery of progenitor cells in the cochlea and rapid progress in drug delivery to the cochlea, biological and pharmaceutical therapies are currently in development to improve the function of the cochlear implant or eliminate the need for it altogether. AREAS COVERED This review highlights progress in emerging regenerative strategies to restore hearing and adjunct therapies to augment the cochlear implant. Novel approaches include the reprogramming of progenitor cells to restore the sensory hair cell population in the cochlea, gene therapy and gene editing to treat hereditary and acquired hearing loss. A detailed review of optogenetics is also presented as a technique that could enable optical stimulation of the spiral ganglion neurons, replacing or complementing electrical stimulation. EXPERT OPINION Increasing evidence of substantial reversal of hearing loss in animal models, alongside rapid advances in delivery strategies to the cochlea and learnings from clinical trials will amalgamate into a biological or pharmaceutical therapy to replace or complement the cochlear implant.
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Affiliation(s)
- Elise Ajay
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Department of Engineering
| | | | - Rachael Richardson
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Medical Bionics Department, Parkville, Victoria, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), East Melbourne, Victoria, Australia
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13
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Chen J, Gao D, Chen J, Hou S, He B, Li Y, Li S, Zhang F, Sun X, Jin Y, Sun L, Yang J. Pseudo-Temporal Analysis of Single-Cell RNA Sequencing Reveals Trans-Differentiation Potential of Greater Epithelial Ridge Cells Into Hair Cells During Postnatal Development of Cochlea in Rats. Front Mol Neurosci 2022; 15:832813. [PMID: 35370544 PMCID: PMC8966675 DOI: 10.3389/fnmol.2022.832813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/08/2022] [Indexed: 11/23/2022] Open
Abstract
The hair cells of the cochlea play a decisive role in the process of hearing damage and recovery, yet knowledge of their regeneration process is still limited. Greater epithelial ridge (GER) cells, a type of cell present during cochlear development that has the characteristics of a precursor sensory cell, disappear at the time of maturation of hearing development. Its development and evolution remain mysterious for many years. Here, we performed single-cell RNA sequencing to profile the gene expression landscapes of rats’ cochlear basal membrane from P1, P7, and P14 and identified eight major subtypes of GER cells. Furthermore, single-cell trajectory analysis for GER cells and hair cells indicated that among the different subtypes of GER, four subtypes had transient cell proliferation after birth and could transdifferentiate into inner and outer hair cells, and two of them mainly transdifferentiated into inner hair cells. The other two subtypes eventually transdifferentiate into outer hair cells. Our study lays the groundwork for elucidating the mechanisms of the key regulatory genes and signaling pathways in the trans-differentiation of GER cell subtypes into hair cells and provides potential clues to understand hair cell regeneration.
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Affiliation(s)
- Jianyong Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Dekun Gao
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Junmin Chen
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Shule Hou
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Baihui He
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Yue Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Shuna Li
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Fan Zhang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Xiayu Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
| | - Yulian Jin
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- *Correspondence: Yulian Jin,
| | - Lianhua Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- Lianhua Sun,
| | - Jun Yang
- Department of Otorhinolaryngology-Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institute of Ear Science, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Key Laboratory of Otolaryngology and Translational Medicine, Shanghai, China
- Jun Yang,
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14
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Zhang YL, Kang M, Wu JC, Xie MY, Xue RY, Tang Q, Yang H, Li LC. Small activating RNA activation of ATOH1 promotes regeneration of human inner ear hair cells. Bioengineered 2022; 13:6729-6739. [PMID: 35246011 PMCID: PMC8974106 DOI: 10.1080/21655979.2022.2045835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
The loss of inner ear hair cells leads to irreversible acoustic injury in mammals, and regeneration of inner ear hair cells to restore hearing loss is challenging. ATOH1 is a key gene in the development and regeneration of hair cells. Small activating RNAs (saRNAs) can target a gene to specifically upregulate its expression. This study aimed to explore whether small activating RNAs could induce the differentiation of human adipose-derived mesenchymal stem cells into hair cell-like cells with a combination of growth factors in vitro and thus provide a new strategy for hair cell regeneration and the treatment of sensorineural hearing loss. Fifteen small activating RNAs targeting the human ATOH1 gene were designed and screened in 293 T and human adipose-derived mesenchymal stem cells, and 3 of these candidates were found to be capable of effectively and stably activating ATOH1 gene expression. The selected small activating RNAs were then transfected into hair cell progenitor cells, and hair cell markers were examined 10 days after transfection. After transfection of the selected small activating RNAs, the expression of the characteristic markers of inner ear hair cells, POU class 4 homeobox 3 (POU4F3) and myosin VIIA (MYO7A), was detected. Human adipose-derived mesenchymal stem cells have the potential to differentiate into human hair cell progenitor cells. In vitro, small activating RNAs were able to induce the differentiation of hair cell progenitor cells into hair cell-like cells. Therefore, RNA activation technology has the potential to provide a new strategy for the regeneration of hair cells.
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Affiliation(s)
- Yong-Li Zhang
- Department of Otolaryngology, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China
| | - Moorim Kang
- Ractigen Therapeutics, Nantong, Jiangsu, China
| | | | - Meng-Yao Xie
- Department of Otolaryngology, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China
| | - Ruo-Yan Xue
- Department of Otolaryngology, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China
| | - Qi Tang
- Department of Otolaryngology, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China
| | - Hua Yang
- Department of Otolaryngology, Peking Union Medical College and Chinese Academy of Medical Sciences, Peking Union Medical College Hospital, Beijing, China
| | - Long-Cheng Li
- Ractigen Therapeutics, Nantong, Jiangsu, China.,Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong, Jiangsu, China
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15
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Li W, Quan Y, Huang M, Wei W, Shu Y, Li H, Chen ZY. A Novel in vitro Model Delineating Hair Cell Regeneration and Neural Reinnervation in Adult Mouse Cochlea. Front Mol Neurosci 2022; 14:757831. [PMID: 35082601 PMCID: PMC8785685 DOI: 10.3389/fnmol.2021.757831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
The study of an adult mammalian auditory system, such as regeneration, has been hampered by the lack of an in vitro system in which hypotheses can be tested efficiently. This is primarily due to the fact that the adult inner ear is encased in the toughest bone of the body, whereas its removal leads to the death of the sensory epithelium in culture. We hypothesized that we could take advantage of the integral cochlear structure to maintain the overall inner ear architecture and improve sensory epithelium survival in culture. We showed that by culturing adult mouse cochlea with the (surrounding) bone intact, the supporting cells (SCs) survived and almost all hair cells (HCs) degenerated. To evaluate the utility of the explant culture system, we demonstrated that the overexpression of Atoh1, an HC fate-determining factor, is sufficient to induce transdifferentiation of adult SCs to HC-like cells (HCLCs). Transdifferentiation-derived HCLCs resemble developmentally young HCs and are able to attract adult ganglion neurites. Furthermore, using a damage model, we showed that degenerated adult ganglions respond to regenerated HCLCs by directional neurite outgrowth that leads to HCLC-neuron contacts, strongly supporting the intrinsic properties of the HCLCs in establishing HCLC-neuron connections. The adult whole cochlear explant culture is suitable for diverse studies of the adult inner ear including regeneration, HC-neuron pathways, and inner ear drug screening.
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Affiliation(s)
- Wenyan Li
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States
- ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Yizhou Quan
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States
| | - Mingqian Huang
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States
| | - Wei Wei
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States
| | - Yilai Shu
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States
- ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- *Correspondence: Huawei Li,
| | - Zheng-Yi Chen
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Technology and Program in Neuroscience, Harvard Medical School, Boston, MA, United States
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, United States
- Zheng-Yi Chen,
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16
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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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17
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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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18
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Abstract
Biologic therapies have the ability to fundamentally change the management of hearing loss; clinicians need to familiarize themselves with their prospective applications in practice. This article reviews the current application of 4 categories of biological therapeutics-growth factors, apoptosis inhibitors, monoclonal antibodies, and gene therapy-in otology and their potential future directions and applications.
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Affiliation(s)
- Steven A Gordon
- Otolaryngology-Head & Neck Surgery, University of Utah Health, 50 North Medical Drive 3C120 SOM, Salt Lake City, UT 84132, USA
| | - Richard K Gurgel
- Otolaryngology-Head & Neck Surgery, University of Utah Health, 50 North Medical Drive 3C120 SOM, Salt Lake City, UT 84132, USA.
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19
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Iyer AA, Groves AK. Transcription Factor Reprogramming in the Inner Ear: Turning on Cell Fate Switches to Regenerate Sensory Hair Cells. Front Cell Neurosci 2021; 15:660748. [PMID: 33854418 PMCID: PMC8039129 DOI: 10.3389/fncel.2021.660748] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Non-mammalian vertebrates can restore their auditory and vestibular hair cells naturally by triggering the regeneration of adjacent supporting cells. The transcription factor ATOH1 is a key regulator of hair cell development and regeneration in the inner ear. Following the death of hair cells, supporting cells upregulate ATOH1 and give rise to new hair cells. However, in the mature mammalian cochlea, such natural regeneration of hair cells is largely absent. Transcription factor reprogramming has been used in many tissues to convert one cell type into another, with the long-term hope of achieving tissue regeneration. Reprogramming transcription factors work by altering the transcriptomic and epigenetic landscapes in a target cell, resulting in a fate change to the desired cell type. Several studies have shown that ATOH1 is capable of reprogramming cochlear non-sensory tissue into cells resembling hair cells in young animals. However, the reprogramming ability of ATOH1 is lost with age, implying that the potency of individual hair cell-specific transcription factors may be reduced or lost over time by mechanisms that are still not clear. To circumvent this, combinations of key hair cell transcription factors have been used to promote hair cell regeneration in older animals. In this review, we summarize recent findings that have identified and studied these reprogramming factor combinations for hair cell regeneration. Finally, we discuss the important questions that emerge from these findings, particularly the feasibility of therapeutic strategies using reprogramming factors to restore human hearing in the future.
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Affiliation(s)
- Amrita A. Iyer
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
| | - Andrew K. Groves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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20
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Crane R, Conley SM, Al-Ubaidi MR, Naash MI. Gene Therapy to the Retina and the Cochlea. Front Neurosci 2021; 15:652215. [PMID: 33815052 PMCID: PMC8010260 DOI: 10.3389/fnins.2021.652215] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/22/2021] [Indexed: 12/20/2022] Open
Abstract
Vision and hearing disorders comprise the most common sensory disorders found in people. Many forms of vision and hearing loss are inherited and current treatments only provide patients with temporary or partial relief. As a result, developing genetic therapies for any of the several hundred known causative genes underlying inherited retinal and cochlear disorders has been of great interest. Recent exciting advances in gene therapy have shown promise for the clinical treatment of inherited retinal diseases, and while clinical gene therapies for cochlear disease are not yet available, research in the last several years has resulted in significant advancement in preclinical development for gene delivery to the cochlea. Furthermore, the development of somatic targeted genome editing using CRISPR/Cas9 has brought new possibilities for the treatment of dominant or gain-of-function disease. Here we discuss the current state of gene therapy for inherited diseases of the retina and cochlea with an eye toward areas that still need additional development.
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Affiliation(s)
- Ryan Crane
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- College of Optometry, University of Houston, Houston, TX, United States
- Depatment of Biology and Biochemistry, University of Houston, Houston, TX, United States
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- College of Optometry, University of Houston, Houston, TX, United States
- Depatment of Biology and Biochemistry, University of Houston, Houston, TX, United States
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21
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Stojkovic M, Han D, Jeong M, Stojkovic P, Stankovic KM. Human induced pluripotent stem cells and CRISPR/Cas-mediated targeted genome editing: Platforms to tackle sensorineural hearing loss. STEM CELLS (DAYTON, OHIO) 2021; 39:673-696. [PMID: 33586253 DOI: 10.1002/stem.3353] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 12/13/2020] [Indexed: 11/09/2022]
Abstract
Hearing loss (HL) is a major global health problem of pandemic proportions. The most common type of HL is sensorineural hearing loss (SNHL) which typically occurs when cells within the inner ear are damaged. Human induced pluripotent stem cells (hiPSCs) can be generated from any individual including those who suffer from different types of HL. The development of new differentiation protocols to obtain cells of the inner ear including hair cells (HCs) and spiral ganglion neurons (SGNs) promises to expedite cell-based therapy and screening of potential pharmacologic and genetic therapies using human models. Considering age-related, acoustic, ototoxic, and genetic insults which are the most frequent causes of irreversible damage of HCs and SGNs, new methods of genome editing (GE), especially the CRISPR/Cas9 technology, could bring additional opportunities to understand the pathogenesis of human SNHL and identify novel therapies. However, important challenges associated with both hiPSCs and GE need to be overcome before scientific discoveries are correctly translated to effective and patient-safe applications. The purpose of the present review is (a) to summarize the findings from published reports utilizing hiPSCs for studies of SNHL, hence complementing recent reviews focused on animal studies, and (b) to outline promising future directions for deciphering SNHL using disruptive molecular and genomic technologies.
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Affiliation(s)
- Miodrag Stojkovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Dongjun Han
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Minjin Jeong
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Petra Stojkovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA
| | - Konstantina M Stankovic
- Eaton Peabody Laboratories, Department of Otolaryngology Head and Neck Surgery, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Department of Otolaryngology Head and Neck Surgery, Harvard Medical School, Boston, Massachusetts, USA.,Program in Speech and Hearing Bioscience and Technology, Harvard University, Cambridge, Massachusetts, USA.,Harvard Program in Therapeutic Science, Harvard Medical School, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
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22
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Ding N, Lee S, Lieber-Kotz M, Yang J, Gao X. Advances in genome editing for genetic hearing loss. Adv Drug Deliv Rev 2021; 168:118-133. [PMID: 32387678 DOI: 10.1016/j.addr.2020.05.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/27/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023]
Abstract
According to the World Health Organization, hearing loss affects over 466 million people worldwide and is the most common human sensory impairment. It is estimated that genetic factors contribute to the causation of approximately 50% of congenital hearing loss. Yet, curative approaches to reversing or preventing genetic hearing impairment are still limited. The clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR-Cas9) systems enable programmable and targeted gene editing in highly versatile manners and offer new gene therapy strategies for genetic hearing loss. Here, we summarize the most common deafness-associated genes, illustrate recent strategies undertaken by using CRISPR-Cas9 systems for targeted gene editing and further compare the CRISPR strategies to non-CRISPR gene therapies. We also examine the merits of different vehicles and delivery forms of genome editing agents. Lastly, we describe the development of animal models that could facilitate the eventual clinical applications of the CRISPR technology to the treatment of genetic hearing diseases.
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23
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Lee S, Song JJ, Beyer LA, Swiderski DL, Prieskorn DM, Acar M, Jen HI, Groves AK, Raphael Y. Combinatorial Atoh1 and Gfi1 induction enhances hair cell regeneration in the adult cochlea. Sci Rep 2020; 10:21397. [PMID: 33293609 PMCID: PMC7722738 DOI: 10.1038/s41598-020-78167-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
Mature mammalian cochlear hair cells (HCs) do not spontaneously regenerate once lost, leading to life-long hearing deficits. Attempts to induce HC regeneration in adult mammals have used over-expression of the HC-specific transcription factor Atoh1, but to date this approach has yielded low and variable efficiency of HC production. Gfi1 is a transcription factor important for HC development and survival. We evaluated the combinatorial effects of Atoh1 and Gfi1 over-expression on HC regeneration using gene transfer methods in neonatal cochlear explants, and in vivo in adult mice. Adenoviral over-expression of Atoh1 and Gfi1 in cultured neonatal cochlear explants resulted in numerous ectopic HC-like cells (HCLCs), with significantly more cells in Atoh1 + Gfi1 cultures than Atoh1 alone. In vitro, ectopic HCLCs emerged in regions medial to inner HCs as well as in the stria vascularis. In vivo experiments were performed in mature Pou4f3DTR mice in which HCs were completely and specifically ablated by administration of diphtheria toxin. Adenoviral expression of Atoh1 or Atoh1 + Gfi1 in cochlear supporting cells induced appearance of HCLCs, with Atoh1 + Gfi1 expression leading to 6.2-fold increase of new HCLCs after 4 weeks compared to Atoh1 alone. New HCLCs were detected throughout the cochlea, exhibited immature stereocilia and survived for at least 8 weeks. Combinatorial Atoh1 and Gfi1 induction is thus a promising strategy to promote HC regeneration in the mature mammalian cochlea.
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Affiliation(s)
- Sungsu Lee
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA
- Department of Otolaryngology - Head and Neck Surgery, Chonnam National University Hospital, Gwangju, South Korea
| | - Jae-Jun Song
- Department of Otolaryngology-Head and Neck Surgery, Korea University College of Medicine, Seoul, South Korea
| | - Lisa A Beyer
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA
| | - Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA
| | - Diane M Prieskorn
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA
| | - Melih Acar
- Department of Medical Biology, School of Medicine, Bahcesehir University, Istanbul, Turkey
| | - Hsin-I Jen
- Department of Neuroscience, Baylor College of Medicine, Houston, USA
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, The University of Michigan, Ann Arbor, MI, USA.
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24
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Abstract
The regulation of gliogenesis is a fundamental process for nervous system development, as the appropriate glial number and identity is required for a functional nervous system. To investigate the molecular mechanisms involved in gliogenesis, we used C. elegans as a model and identified the function of the proneural gene lin-32/Atoh1 in gliogenesis. We found that lin-32 functions during embryonic development to negatively regulate the number of AMsh glia. The ectopic AMsh cells at least partially arise from cells originally fated to become CEPsh glia, suggesting that lin-32 is involved in the specification of specific glial subtypes. Moreover, we show that lin-32 acts in parallel with cnd-1/ NeuroD1 and ngn-1/ Neurog1 in negatively regulating an AMsh glia fate. Furthermore, expression of murine Atoh1 fully rescues lin-32 mutant phenotypes, suggesting lin-32/Atoh1 may have a conserved role in glial specification.
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25
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Shibata SB, West MB, Du X, Iwasa Y, Raphael Y, Kopke RD. Gene therapy for hair cell regeneration: Review and new data. Hear Res 2020; 394:107981. [DOI: 10.1016/j.heares.2020.107981] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/19/2020] [Accepted: 04/22/2020] [Indexed: 02/06/2023]
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26
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Inner Ear Gene Therapies Take Off: Current Promises and Future Challenges. J Clin Med 2020; 9:jcm9072309. [PMID: 32708116 PMCID: PMC7408650 DOI: 10.3390/jcm9072309] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 11/16/2022] Open
Abstract
Hearing impairment is the most frequent sensory deficit in humans of all age groups, from children (1/500) to the elderly (more than 50% of the over-75 s). Over 50% of congenital deafness are hereditary in nature. The other major causes of deafness, which also may have genetic predisposition, are aging, acoustic trauma, ototoxic drugs such as aminoglycosides, and noise exposure. Over the last two decades, the study of inherited deafness forms and related animal models has been instrumental in deciphering the molecular, cellular, and physiological mechanisms of disease. However, there is still no curative treatment for sensorineural deafness. Hearing loss is currently palliated by rehabilitation methods: conventional hearing aids, and for more severe forms, cochlear implants. Efforts are continuing to improve these devices to help users to understand speech in noisy environments and to appreciate music. However, neither approach can mediate a full recovery of hearing sensitivity and/or restoration of the native inner ear sensory epithelia. New therapeutic approaches based on gene transfer and gene editing tools are being developed in animal models. In this review, we focus on the successful restoration of auditory and vestibular functions in certain inner ear conditions, paving the way for future clinical applications.
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27
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Durán-Alonso MB. Stem cell-based approaches: Possible route to hearing restoration? World J Stem Cells 2020; 12:422-437. [PMID: 32742560 PMCID: PMC7360988 DOI: 10.4252/wjsc.v12.i6.422] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/08/2020] [Accepted: 05/22/2020] [Indexed: 02/06/2023] Open
Abstract
Disabling hearing loss is the most common sensorineural disability worldwide. It affects around 466 million people and its incidence is expected to rise to around 900 million people by 2050, according to World Health Organization estimates. Most cases of hearing impairment are due to the degeneration of hair cells (HCs) in the cochlea, mechano-receptors that transduce incoming sound information into electrical signals that are sent to the brain. Damage to these cells is mainly caused by exposure to aminoglycoside antibiotics and to some anti-cancer drugs such as cisplatin, loud sounds, age, infections and genetic mutations. Hearing deficits may also result from damage to the spiral ganglion neurons that innervate cochlear HCs. Differently from what is observed in avian and non-mammalian species, there is no regeneration of missing sensory cell types in the adult mammalian cochlea, what makes hearing loss an irreversible process. This review summarizes the research that has been conducted with the aim of developing cell-based strategies that lead to sensory cell replacement in the adult cochlea and, ultimately, to hearing restoration. Two main lines of research are discussed, one directed toward the transplantation of exogenous replacement cells into the damaged tissue, and another that aims at reactivating the regenerative potential of putative progenitor cells in the adult inner ear. Results from some of the studies that have been conducted are presented and the advantages and drawbacks of the various approaches discussed.
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28
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Spatiotemporally controlled overexpression of cyclin D1 triggers generation of supernumerary cells in the postnatal mouse inner ear. Hear Res 2020; 390:107951. [PMID: 32244147 DOI: 10.1016/j.heares.2020.107951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 02/04/2020] [Accepted: 03/10/2020] [Indexed: 02/06/2023]
Abstract
The retinoblastoma family of pocket proteins (pRBs), composed of Rb1, p107, and p130 are negative regulators of cell-cycle progression. The deletion of any individual pRB in the auditory system triggers hair cells' (HCs) and supporting cells' (SCs) proliferation to different extents. Nevertheless, accessing their combined role in the inner ear through conditional or complete knockout methods is limited by the early mortality of the triple knockout. In quiescent cells, hyperphosphorylation and inactivation of the pRBs are maintained through the activity of the Cyclin-D1-cdk4/6 complex. Cyclin D1 (CycD1) is expressed in the embryonic and neonatal inner ear. In the mature organ of Corti (OC), CycD1 expression is significantly downregulated, paralleling the OC mitotic quiescence. Earlier studies showed that CycD1 overexpression leads to cell-cycle reactivation in cultures of inner ear explants. Here, we characterize a Cre-activated, Doxycycline (Dox)-controlled, conditional CycD1 overexpression model, which when bred to a tetracycline-controlled transcriptional activator and the Atoh1-cre mouse lines, allow for transient CycD1 overexpression and pRBs' downregulation in the inner ear in a reversible fashion. Analyses of postnatal mice's inner ears at various time points revealed the presence of supernumerary cells throughout the length of the cochlea and in the vestibular end-organs. Notably, most supernumerary cells were observed in the inner hair cells' (IHCs) region, expressed myosin VIIa (M7a), and showed no signs of apoptosis at any of the time points analyzed. Auditory and vestibular phenotypes were similar between the different genotypes and treatment groups. The fact that no significant differences were observed in auditory and vestibular function supports the notion that the supernumerary cells detected in the adult mice cochlea and macular end-organs may not impair auditory functions.
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29
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Lee S, Dondzillo A, Gubbels SP, Raphael Y. Practical aspects of inner ear gene delivery for research and clinical applications. Hear Res 2020; 394:107934. [PMID: 32204962 DOI: 10.1016/j.heares.2020.107934] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/26/2020] [Accepted: 02/28/2020] [Indexed: 12/24/2022]
Abstract
The application of gene therapy is widely expanding in research and continuously improving in preparation for clinical applications. The inner ear is an attractive target for gene therapy for treating environmental and genetic diseases in both the auditory and vestibular systems. With the lack of spontaneous cochlear hair cell replacement, hair cell regeneration in adult mammals is among the most important goals of gene therapy. In addition, correcting gene defects can open up a new era for treating inner ear diseases. The relative isolation and small size of the inner ear dictate local administration routes and carefully calculated small volumes of reagents. In the current review, we will cover effective timing, injection routes and types of vectors for successful gene delivery to specific target cells within the inner ear. Differences between research purposes and clinical applications are also discussed.
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Affiliation(s)
- Sungsu Lee
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, Michigan Medicine, Ann Arbor, MI, USA
| | - Anna Dondzillo
- Department of Otolaryngology, Head and Neck Surgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Samuel P Gubbels
- Department of Otolaryngology, Head and Neck Surgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology, Head and Neck Surgery, Michigan Medicine, Ann Arbor, MI, USA.
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30
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Van De Water TR. Historical Aspects of Gene Therapy and Stem Cell Therapy in the Treatment of Hearing and Balance Disorder. Anat Rec (Hoboken) 2020; 303:390-407. [DOI: 10.1002/ar.24332] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/18/2019] [Accepted: 11/22/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Thomas R. Van De Water
- Cochlear Implant Research Program, Department of Otolaryngology, University of Miami Ear InstituteUniversity of Miami Miller School of Medicine Miami Florida
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31
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Zheng Y, Luo W, Ma R, Cong N, Ren D, Chi F, Yang J. The Atoh1 expression levels are correlated with the arrangement, ciliary morphology, and electrophysiological characteristics of ectopic hair cell-like cells. Neurosci Lett 2020; 720:134758. [PMID: 31945449 DOI: 10.1016/j.neulet.2020.134758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/15/2019] [Accepted: 01/13/2020] [Indexed: 10/25/2022]
Abstract
Previous reports have suggested that the level and duration of Atoh1 expression are correlated with the survival, arrangement and stereociliary bundle-related morphology of hair cells during development, but whether Atoh1 expression levels are correlated with the arrangement, bundle formation and electrophysiological characteristics of newly formed hair cells is unknown. To address this question, cultured cochlear explants obtained from neonatal rats were treated with different titers of a human adenovirus serotype 5 (Ad5) vector encoding Atoh1 and/or EGFP (EGFP-Atoh1+/-). The results showed that higher EGFP-Atoh1 concentrations led to higher initial Atoh1 mRNA expression levels and induced greater numbers of ectopic hair cell-like cells (EHCLCs) in the lesser epithelial ridge (LER). Furthermore, gradual increases in the number of EHCLCs were associated with the progressive conversion of the LER region similarly to that of hair cells during development. Some of the cilia on EHCLCs with higher Atoh1 expression were regularly arranged in a manner similar to that of normal hair bundles. As demonstrated through patch clamp recordings, high Atoh1 expression was associated with significantly decreased proportions of cells with Ih currents, significantly reduced proportions of transient potassium channel currents, and potassium channel currents with a greatly increased mean amplitude, which indicated that EHCLCs with high Atoh1 expression were more mature than those with low Atoh1 expression. Overall, the evidence suggests that the Atoh1 expression levels affect not only the arrangement and ciliary morphology of hair cells but also the electrophysiological characteristics of Atoh1-induced EHCLCs, and these findings provide important guidance for future therapies aimed at treating deafness.
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Affiliation(s)
- Yu Zheng
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Clinical Medical Center of Hearing Medicine, Shanghai 200031, China; Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China
| | - Wenwei Luo
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Clinical Medical Center of Hearing Medicine, Shanghai 200031, China; Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China
| | - Rui Ma
- Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China
| | - Ning Cong
- Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China
| | - Dongdong Ren
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Clinical Medical Center of Hearing Medicine, Shanghai 200031, China; Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China.
| | - Fanglu Chi
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Clinical Medical Center of Hearing Medicine, Shanghai 200031, China; Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China.
| | - Juanmei Yang
- Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital, Fudan University, Shanghai 200031, China; Shanghai Clinical Medical Center of Hearing Medicine, Shanghai 200031, China; Key Laboratory of Hearing Medicine of National Health Commission of the People's Republic of China, Shanghai 20031, China; Research Institute of Otolaryngology, Fudan University, Shanghai 200031, China.
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32
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Shu Y, Li W, Huang M, Quan YZ, Scheffer D, Tian C, Tao Y, Liu X, Hochedlinger K, Indzhykulian AA, Wang Z, Li H, Chen ZY. Renewed proliferation in adult mouse cochlea and regeneration of hair cells. Nat Commun 2019; 10:5530. [PMID: 31797926 PMCID: PMC6892913 DOI: 10.1038/s41467-019-13157-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 10/13/2019] [Indexed: 12/23/2022] Open
Abstract
The adult mammalian inner ear lacks the capacity to divide or regenerate. Damage to inner ear generally leads to permanent hearing loss in humans. Here, we present that reprogramming of the adult inner ear induces renewed proliferation and regeneration of inner ear cell types. Co-activation of cell cycle activator Myc and inner ear progenitor gene Notch1 induces robust proliferation of diverse adult cochlear sensory epithelial cell types. Transient MYC and NOTCH activities enable adult supporting cells to respond to transcription factor Atoh1 and efficiently transdifferentiate into hair cell-like cells. Furthermore, we uncover that mTOR pathway participates in MYC/NOTCH-mediated proliferation and regeneration. These regenerated hair cell-like cells take up the styryl dye FM1-43 and are likely to form connections with adult spiral ganglion neurons, supporting that Myc and Notch1 co-activation is sufficient to reprogram fully mature supporting cells to proliferate and regenerate hair cell-like cells in adult mammalian auditory organs.
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MESH Headings
- Animals
- Cell Proliferation/genetics
- Cell Proliferation/physiology
- Cochlea/cytology
- Cochlea/metabolism
- Cochlea/physiology
- Ear, Inner/cytology
- Ear, Inner/metabolism
- Ear, Inner/physiology
- Epithelial Cells/cytology
- Epithelial Cells/metabolism
- Epithelial Cells/physiology
- Ganglia, Sensory/cytology
- Ganglia, Sensory/metabolism
- Ganglia, Sensory/physiology
- Gene Expression Regulation
- Hair Cells, Auditory, Inner/metabolism
- Hair Cells, Auditory, Inner/physiology
- Humans
- Mice
- Proto-Oncogene Proteins c-myc/genetics
- Proto-Oncogene Proteins c-myc/metabolism
- Receptor, Notch1/genetics
- Receptor, Notch1/metabolism
- Regeneration/genetics
- Regeneration/physiology
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Affiliation(s)
- Yilai Shu
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Biomedcial Sciences, Fudan University, 200031, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Wenyan Li
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Biomedcial Sciences, Fudan University, 200031, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Mingqian Huang
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Yi-Zhou Quan
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Deborah Scheffer
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
- Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Chunjie Tian
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Yong Tao
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami School of Medicine, Miami, FL, 33136, USA
| | - Konrad Hochedlinger
- Department of Molecular Biology, Cancer Center and Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
- Department of Stem Cell and Regenerative Biology and Harvard Stem Cell Institute, Cambridge, MA, 02138, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA
| | - Artur A Indzhykulian
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA
| | - Zhengmin Wang
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Biomedcial Sciences, Fudan University, 200031, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department of the Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Institutes of Biomedcial Sciences, Fudan University, 200031, Shanghai, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, 200031, China
| | - Zheng-Yi Chen
- Department of Otolaryngology-Head and Neck Surgery, Graduate Program in Speech and Hearing Bioscience and Techology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA.
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA.
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33
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Atoh1 is required in supporting cells for regeneration of vestibular hair cells in adult mice. Hear Res 2019; 385:107838. [PMID: 31751832 DOI: 10.1016/j.heares.2019.107838] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 11/20/2022]
Abstract
In amniotes, head movements are encoded by two types of vestibular hair cells (type I and type II) with unique morphology, physiology, and innervation. After hair cell destruction in mature rodents, supporting cells regenerate some type II hair cells, but no type I hair cells are replaced. The transcription factor Atoh1 is required for hair cell development, and Atoh1 is upregulated in supporting cells, the hair cell progenitors, in mature chickens and mice following hair cell damage. We investigated whether Atoh1 is required for type II hair cell regeneration in adult mice after genetic ablation of hair cells. First, we used a knock-in Atoh1 reporter to demonstrate that supporting cells in the utricle, a vestibular organ that detects linear acceleration of the head, upregulate Atoh1 expression by 7 days after hair cell destruction was initiated. Next, we labeled supporting cells prior to damage and fate-mapped them over time to test whether conditional deletion of Atoh1 from supporting cells prevented them from converting into hair cells after damage. In mice with normal Atoh1 expression, fate-mapped supporting cells in the adult utricle gave rise to hundreds of type II hair cells after hair cell destruction, but they did not form new type I hair cells. By contrast, mice with Atoh1 deletion prior to hair cell damage had only 10-20 fate-mapped type II hair cells per utricle at 3 weeks post-damage, and numbers did not change at 12 weeks after hair cell destruction. Supporting cells had normal cell shape and nuclear density up to 12 weeks after Atoh1 deletion. Similar observations were made in two other vestibular organs, the saccule and the lateral ampulla. Our findings demonstrate that Atoh1 is necessary in adult mouse supporting cells for regeneration of type II vestibular hair cells and that deletion of Atoh1 from supporting cells prior to damage does not appear to induce supporting cells to die or to proliferate.
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Abstract
Over 450 million people worldwide suffer from hearing loss, leading to an estimated economic burden of ∼$750 billion. The past decade has seen significant advances in the understanding of the molecular mechanisms that contribute to hearing, and the environmental and genetic factors that can go awry and lead to hearing loss. This in turn has sparked enormous interest in developing gene therapy approaches to treat this disorder. This review documents the most recent advances in cochlear gene therapy to restore hearing loss, and will cover viral vectors and construct designs, potential routes of delivery into the inner ear, and, lastly, the most promising genes of interest.
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Affiliation(s)
- Lawrence Lustig
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Medical Center, New York Presbyterian Hospital, New York, New York 10032
| | - Omar Akil
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, California 94117
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Pinyon JL, von Jonquieres G, Crawford EN, Duxbury M, Al Abed A, Lovell NH, Klugmann M, Wise AK, Fallon JB, Shepherd RK, Birman CS, Lai W, McAlpine D, McMahon C, Carter PM, Enke YL, Patrick JF, Schilder AG, Marie C, Scherman D, Housley GD. Neurotrophin gene augmentation by electrotransfer to improve cochlear implant hearing outcomes. Hear Res 2019; 380:137-149. [DOI: 10.1016/j.heares.2019.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 12/14/2022]
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AAV-ie enables safe and efficient gene transfer to inner ear cells. Nat Commun 2019; 10:3733. [PMID: 31427575 PMCID: PMC6700137 DOI: 10.1038/s41467-019-11687-8] [Citation(s) in RCA: 121] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/17/2019] [Indexed: 12/17/2022] Open
Abstract
Hearing loss is the most common sensory disorder. While gene therapy has emerged as a promising treatment of inherited diseases like hearing loss, it is dependent on the identification of gene delivery vectors. Adeno-associated virus (AAV) vector-mediated gene therapy has been approved in the US for treating a rare inherited eye disease but no safe and efficient vectors have been identified that can target the diverse types of inner ear cells. Here, we identify an AAV variant, AAV-inner ear (AAV-ie), for gene delivery in mouse inner ear. Our results show that AAV-ie transduces the cochlear supporting cells (SCs) with high efficiency, representing a vast improvement over conventional AAV serotypes. Furthermore, after AAV-ie-mediated transfer of the Atoh1 gene, we find that many SCs trans-differentiated into new HCs. Our results suggest that AAV-ie is a useful tool for the cochlear gene therapy and for investigating the mechanism of HC regeneration. There are currently few AAV vectors that can effectively target the diverse cell types of the inner ear. Here the authors design AAV-ie for gene delivery to the mouse cochlea, targeting cochlear supporting cells.
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Sánchez-Guardado LÓ, Puelles L, Hidalgo-Sánchez M. Origin of acoustic-vestibular ganglionic neuroblasts in chick embryos and their sensory connections. Brain Struct Funct 2019; 224:2757-2774. [PMID: 31396696 DOI: 10.1007/s00429-019-01934-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/31/2019] [Indexed: 01/03/2023]
Abstract
The inner ear is a complex three-dimensional sensory structure with auditory and vestibular functions. It originates from the otic placode, which generates the sensory elements of the membranous labyrinth and all the ganglionic neuronal precursors. Neuroblast specification is the first cell differentiation event. In the chick, it takes place over a long embryonic period from the early otic cup stage to at least stage HH25. The differentiating ganglionic neurons attain a precise innervation pattern with sensory patches, a process presumably governed by a network of dendritic guidance cues which vary with the local micro-environment. To study the otic neurogenesis and topographically-ordered innervation pattern in birds, a quail-chick chimaeric graft technique was used in accordance with a previously determined fate-map of the otic placode. Each type of graft containing the presumptive domain of topologically-arranged placodal sensory areas was shown to generate neuroblasts. The differentiated grafted neuroblasts established dendritic contacts with a variety of sensory patches. These results strongly suggest that, rather than reverse-pathfinding, the relevant role in otic dendritic process guidance is played by long-range diffusing molecules.
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Affiliation(s)
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology, School of Medicine, University of Murcia, E30100, Murcia, Spain.,Instituto Murciano de Investigaciones Biosanitarias (IMIB-Arrixaca), E30100, Murcia, Spain
| | - Matías Hidalgo-Sánchez
- Department of Cell Biology, School of Science, University of Extremadura, E06071, Badajoz, Spain.
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Abstract
Despite impressive technical progress in the field of conventional hearing aids and implantable hearing systems, the hopes for the treatment of inner ear diseases such as hearing loss and tinnitus have become increasingly directed toward regenerative therapeutic approaches. This review discusses the currently most promising strategies for hair cell regeneration in the inner ear to treat hearing loss, including stem cell-based, gene transfer-based, and pharmacological interventions. Furthermore, previous milestones and ground-breaking work in this scientific field are identified. After many years of basic research, the first clinical trials with a regenerative therapeutic approach for hearing-impaired patients were recently initiated. Although there is still a long and bumpy road ahead until a true breakthrough is achieved, it seems more realistic than ever that regenerative therapies for the inner ear will find their way into clinical practice.
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Affiliation(s)
- M Diensthuber
- Klinik für Hals-Nasen-Ohrenheilkunde, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt/M., Deutschland.
| | - T Stöver
- Klinik für Hals-Nasen-Ohrenheilkunde, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt/M., Deutschland
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Hou K, Jiang H, Karim MR, Zhong C, Xu Z, Liu L, Guan M, Shao J, Huang X. A Critical E-box in Barhl1 3' Enhancer Is Essential for Auditory Hair Cell Differentiation. Cells 2019; 8:cells8050458. [PMID: 31096644 PMCID: PMC6562609 DOI: 10.3390/cells8050458] [Citation(s) in RCA: 9] [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: 04/10/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 02/05/2023] Open
Abstract
Barhl1, a mouse homologous gene of Drosophila BarH class homeobox genes, is highly expressed within the inner ear and crucial for the long-term maintenance of auditory hair cells that mediate hearing and balance, yet little is known about the molecular events underlying Barhl1 regulation and function in hair cells. In this study, through data mining and in vitro report assay, we firstly identified Barhl1 as a direct target gene of Atoh1 and one E-box (E3) in Barhl1 3’ enhancer is crucial for Atoh1-mediated Barhl1 activation. Then we generated a mouse embryonic stem cell (mESC) line carrying disruptions on this E3 site E-box (CAGCTG) using CRISPR/Cas9 technology and this E3 mutated mESC line is further subjected to an efficient stepwise hair cell differentiation strategy in vitro. Disruptions on this E3 site caused dramatic loss of Barhl1 expression and significantly reduced the number of induced hair cell-like cells, while no affections on the differentiation toward early primitive ectoderm-like cells and otic progenitors. Finally, through RNA-seq profiling and gene ontology (GO) enrichment analysis, we found that this E3 box was indispensable for Barhl1 expression to maintain hair cell development and normal functions. We also compared the transcriptional profiles of induced cells from CDS mutated and E3 mutated mESCs, respectively, and got very consistent results except the Barhl1 transcript itself. These observations indicated that Atoh1-mediated Barhl1 expression could have important roles during auditory hair cell development. In brief, our findings delineate the detail molecular mechanism of Barhl1 expression regulation in auditory hair cell differentiation.
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Affiliation(s)
- Kun Hou
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Hui Jiang
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Md Rezaul Karim
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
- Department of Biotechnology and Genetic Engineering, Faculty of Biological Sciences, Islamic University, Kushtia 7003, Bangladesh.
| | - Chao Zhong
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Zhouwen Xu
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Lin Liu
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
| | - Minxin Guan
- Institute of Genetics, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| | - Jianzhong Shao
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
- Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou 310058, China.
| | - Xiao Huang
- Institute of Cell and Developmental Biology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
- Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Hangzhou 310058, China.
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Sakagami M, Ouji Y, Kawai N, Misu M, Yoshikawa M, Kitahara T. Differentiation of embryonic stem cells into inner ear vestibular hair cells using vestibular cell derived-conditioned medium. Biochem Biophys Rep 2019; 19:100649. [PMID: 31193276 PMCID: PMC6525281 DOI: 10.1016/j.bbrep.2019.100649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/19/2019] [Accepted: 05/03/2019] [Indexed: 01/12/2023] Open
Abstract
Vestibular hair cells (V-HCs) in the inner ear have important roles and various functions. When V-HCs are damaged, crippling symptoms, such as vertigo, visual field oscillation, and imbalance, are often seen. Recently, several studies have reported differentiation of embryonic stem (ES) cells, as pluripotent stem cells, to HCs, though a method for producing V-HCs has yet to be established. In the present study, we used vestibular cell conditioned medium (V-CM) and effectively induced ES cells to differentiate into V-HCs. Expressions of V-HC-related markers (Math1, Myosin6, Brn3c, Dnah5) were significantly increased in ES cells cultured in V-CM for 2 weeks, while those were not observed in ES cells cultured without V-CM. On the other hand, the cochlear HC-related marker Lmod3 was either not detected or detected only faintly in those cells when cultured in V-CM. Our results demonstrate that V-CM has an ability to specifically induce differentiation of ES cells into V-HCs.
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Affiliation(s)
- Masaharu Sakagami
- Department of Otolaryngology - Head and Neck Surgery, Nara Medical University, Kashihara, Nara, Japan.,Department of Pathogen, Infection and Immunity, Nara Medical University, Kashihara, Nara, Japan
| | - Yukiteru Ouji
- Department of Pathogen, Infection and Immunity, Nara Medical University, Kashihara, Nara, Japan
| | - Norikazu Kawai
- Department of Pathogen, Infection and Immunity, Nara Medical University, Kashihara, Nara, Japan
| | - Masayasu Misu
- Department of Pathogen, Infection and Immunity, Nara Medical University, Kashihara, Nara, Japan
| | - Masahide Yoshikawa
- Department of Pathogen, Infection and Immunity, Nara Medical University, Kashihara, Nara, Japan
| | - Tadashi Kitahara
- Department of Otolaryngology - Head and Neck Surgery, Nara Medical University, Kashihara, Nara, Japan
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41
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Ma Y, Wise AK, Shepherd RK, Richardson RT. New molecular therapies for the treatment of hearing loss. Pharmacol Ther 2019; 200:190-209. [PMID: 31075354 DOI: 10.1016/j.pharmthera.2019.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
An estimated 466 million people suffer from hearing loss worldwide. Sensorineural hearing loss is characterized by degeneration of key structures of the sensory pathway in the cochlea such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells - the ribbon synapse. Various strategies to protect or regenerate these sensory cells and structures are the subject of intensive research. Yet despite recent advances in our understandings of the capacity of the cochlea for repair and regeneration there are currently no pharmacological or biological interventions for hearing loss. Current research focusses on localized cochlear drug, gene and cell-based therapies. One of the more promising drug-based therapies is based on neurotrophic factors for the repair of the ribbon synapse after noise exposure, as well as preventing loss of primary auditory neurons and regrowth of the auditory neuron fibers after severe hearing loss. Drug therapy delivery technologies are being employed to address the specific needs of neurotrophin and other therapies for hearing loss that include the need for high doses, long-term delivery, localised or cell-specific targeting and techniques for their safe and efficacious delivery to the cochlea. Novel biomaterials are enabling high payloads of drugs to be administered to the cochlea with subsequent slow-release properties that are proving to be beneficial for treating hearing loss. In parallel, new gene therapy technologies are addressing the need for cell specificity and high efficacy for the treatment of both genetic and acquired hearing loss with promising reports of hearing recovery. Some biomaterials and cell therapies are being used in conjunction with the cochlear implant ensuring therapeutic benefit to the primary neurons during electrical stimulation. This review will introduce the auditory system, hearing loss and the potential for repair and regeneration in the cochlea. Drug delivery to the cochlea will then be reviewed, with a focus on new biomaterials, gene therapy technologies, cell therapy and the use of the cochlear implant as a vehicle for drug delivery. With the current pre-clinical research effort into therapies for hearing loss, including clinical trials for gene therapy, the future for the treatment for hearing loss is looking bright.
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Affiliation(s)
- Yutian Ma
- Bionics Institute, East Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Australia; University of Melbourne, Department of Chemical Engineering, Parkville, Victoria, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Robert K Shepherd
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia.
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42
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Jen HI, Hill MC, Tao L, Sheng K, Cao W, Zhang H, Yu HV, Llamas J, Zong C, Martin JF, Segil N, Groves AK. Transcriptomic and epigenetic regulation of hair cell regeneration in the mouse utricle and its potentiation by Atoh1. eLife 2019; 8:e44328. [PMID: 31033441 PMCID: PMC6504235 DOI: 10.7554/elife.44328] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/28/2019] [Indexed: 12/30/2022] Open
Abstract
The mammalian cochlea loses its ability to regenerate new hair cells prior to the onset of hearing. In contrast, the adult vestibular system can produce new hair cells in response to damage, or by reprogramming of supporting cells with the hair cell transcription factor Atoh1. We used RNA-seq and ATAC-seq to probe the transcriptional and epigenetic responses of utricle supporting cells to damage and Atoh1 transduction. We show that the regenerative response of the utricle correlates with a more accessible chromatin structure in utricle supporting cells compared to their cochlear counterparts. We also provide evidence that Atoh1 transduction of supporting cells is able to promote increased transcriptional accessibility of some hair cell genes. Our study offers a possible explanation for regenerative differences between sensory organs of the inner ear, but shows that additional factors to Atoh1 may be required for optimal reprogramming of hair cell fate.
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Affiliation(s)
- Hsin-I Jen
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Matthew C Hill
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
| | - Litao Tao
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Kuanwei Sheng
- Program in Integrative Molecular and Biomedical SciencesBaylor College of MedicineHoustonUnited States
| | - Wenjian Cao
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - Hongyuan Zhang
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
| | - Haoze V Yu
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Juan Llamas
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Chenghang Zong
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonUnited States
| | - James F Martin
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of Molecular Physiology and BiophysicsBaylor College of MedicineHoustonUnited States
- The Texas Heart InstituteHoustonUnited States
| | - Neil Segil
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
- Caruso Department of Otolaryngology - Head and Neck Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesUnited States
| | - Andrew K Groves
- Program in Developmental BiologyBaylor College of MedicineHoustonUnited States
- Department of NeuroscienceBaylor College of MedicineHoustonUnited States
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43
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Eshraghi AA, Jung HD, Mittal R. Recent Advancements in Gene and Stem Cell-Based Treatment Modalities: Potential Implications in Noise-Induced Hearing Loss. Anat Rec (Hoboken) 2019; 303:516-526. [PMID: 30859735 DOI: 10.1002/ar.24107] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/24/2018] [Accepted: 08/23/2018] [Indexed: 12/13/2022]
Abstract
Noise-induced hearing loss (NIHL) poses a significant burden on not only the economics of health care but also the quality of life of an individual, as we approach an unprecedented age of longevity. In this article, we will delineate the current landscape of management of NIHL. We discuss the most recent results from in vitro and in vivo studies that determine the effectiveness of established pharmacotherapy such as corticosteroid and potential emerging therapies like N-acetyl cysteine and neurotrophins (NTs), as well as highlight ongoing clinical trials for these therapeutic agents. We present an overview of how the recent advancements in the field of gene-based and stem cell-based therapies can help in developing effective therapeutic strategies for NIHL. Gene-based therapies have shown exciting results demonstrating cochlear cellular regeneration using Atoh1, NRF2 as well as NT gene therapy employing viral vectors. In addition, we will discuss the recent advancements in genome-editing technologies, such as CRISPR/Cas9, and its potential role in NIHL therapy. We will further discuss the current state of stem cell therapy as it pertains to treating neurodegenerative conditions including NIHL. Embryonic stem cells, adult-derived stem cells, and induced pluripotent stem cells all represent an enticing reservoir of replacing damaged cells as a result of NIHL. Finally, we will discuss the barriers that need to be overcome to translate these promising treatment modalities to the clinical practice in pursuit of improving quality of life of patients having NIHL. Anat Rec, 303:516-526, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Adrien A Eshraghi
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida
| | - Hyunseo D Jung
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida
| | - Rahul Mittal
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, Florida
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44
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Translating animal models to human therapeutics in noise-induced and age-related hearing loss. Hear Res 2019; 377:44-52. [PMID: 30903954 DOI: 10.1016/j.heares.2019.03.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/15/2019] [Accepted: 03/05/2019] [Indexed: 11/20/2022]
Abstract
Acquired sensorineural hearing loss is one of the most prevalent chronic diseases, and aging and acoustic overexposure are common contributors. Decades of study in animals and humans have clarified the cellular targets and perceptual consequences of these forms of hearing loss, and preclinical studies have led to the development of therapeutics designed to slow, prevent or reverse them. Here, we review the histopathological changes underlying age-related and noise-induced hearing loss and the functional consequences of these pathologies. Based on these relations, we consider the ambiguities that arise in diagnosing underlying pathology from minimally invasive tests of auditory function, and how those ambiguities present challenges in the design and interpretation of clinical trials.
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45
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Zhong C, Fu Y, Pan W, Yu J, Wang J. Atoh1 and other related key regulators in the development of auditory sensory epithelium in the mammalian inner ear: function and interplay. Dev Biol 2019; 446:133-141. [DOI: 10.1016/j.ydbio.2018.12.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/30/2018] [Accepted: 12/30/2018] [Indexed: 01/08/2023]
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46
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Atkinson PJ, Kim GS, Cheng AG. Direct cellular reprogramming and inner ear regeneration. Expert Opin Biol Ther 2019; 19:129-139. [PMID: 30584811 DOI: 10.1080/14712598.2019.1564035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
INTRODUCTION Sound is integral to communication and connects us to the world through speech and music. Cochlear hair cells are essential for converting sounds into neural impulses. However, these cells are highly susceptible to damage from an array of factors, resulting in degeneration and ultimately irreversible hearing loss in humans. Since the discovery of hair cell regeneration in birds, there have been tremendous efforts to identify therapies that could promote hair cell regeneration in mammals. AREAS COVERED Here, we will review recent studies describing spontaneous hair cell regeneration and direct cellular reprograming as well as other factors that mediate mammalian hair cell regeneration. EXPERT OPINION Numerous combinatorial approaches have successfully reprogrammed non-sensory supporting cells to form hair cells, albeit with limited efficacy and maturation. Studies on epigenetic regulation and transcriptional network of hair cell progenitors may accelerate discovery of more promising reprogramming regimens.
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Affiliation(s)
- Patrick J Atkinson
- a Department of Otolaryngology-Head and Neck Surgery , Stanford University School of Medicine , Stanford , CA , USA
| | - Grace S Kim
- a Department of Otolaryngology-Head and Neck Surgery , Stanford University School of Medicine , Stanford , CA , USA
| | - Alan G Cheng
- a Department of Otolaryngology-Head and Neck Surgery , Stanford University School of Medicine , Stanford , CA , USA
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Carpena NT, Lee MY. Genetic Hearing Loss and Gene Therapy. Genomics Inform 2018; 16:e20. [PMID: 30602081 PMCID: PMC6440668 DOI: 10.5808/gi.2018.16.4.e20] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 12/04/2018] [Indexed: 12/15/2022] Open
Abstract
Genetic hearing loss crosses almost all the categories of hearing loss which includes the following: conductive, sensory, and neural; syndromic and nonsyndromic; congenital, progressive, and adult onset; high-frequency, low-frequency, or mixed frequency; mild or profound; and recessive, dominant, or sex-linked. Genes play a role in almost half of all cases of hearing loss but effective treatment options are very limited. Genetic hearing loss is considered to be extremely genetically heterogeneous. The advancements in genomics have been instrumental to the identification of more than 6,000 causative variants in more than 150 genes causing hearing loss. Identification of genes for hearing impairment provides an increased insight into the normal development and function of cells in the auditory system. These defective genes will ultimately be important therapeutic targets. However, the auditory system is extremely complex which requires tremendous advances in gene therapy including gene vectors, routes of administration, and therapeutic approaches. This review summarizes and discusses recent advances in elucidating the genomics of genetic hearing loss and technologies aimed at developing a gene therapy that may become a treatment option for in the near future.
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Affiliation(s)
- Nathanial T Carpena
- Department of Otolaryngology-Head and Neck Surgery, Dankook University College of Medicine, Cheonan 31116, Korea
| | - Min Young Lee
- Department of Otolaryngology-Head and Neck Surgery, Dankook University College of Medicine, Cheonan 31116, Korea.,Beckman Laser Institute Korea, Dankook University, Cheonan 31116, Korea
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48
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Molecular therapy for genetic and degenerative vestibular disorders. Curr Opin Otolaryngol Head Neck Surg 2018; 26:307-311. [PMID: 30045104 DOI: 10.1097/moo.0000000000000477] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW The primary purpose of this review is to summarize current literature in the field of vestibular regeneration with a focus on recent developments in molecular and gene therapies. RECENT FINDINGS Since the discovery of limited vestibular hair cell regeneration in mammals in the 1990s, many elegant studies have improved our knowledge of mechanisms of development and regeneration of the vestibular system. A better understanding of the developmental pathways of the vestibular organs has fueled various biological strategies to enhance regeneration, including novel techniques in deriving vestibular hair cells from embryonic and induced pluripotent stem cells. In addition, the identification of specific genetic mutations responsible for vestibular disorders has opened various opportunities for gene replacement therapy. SUMMARY Vestibular dysfunction is a significant clinical problem with limited therapeutic options, warranting research on biological strategies to repair/regenerate the vestibular organs to restore function. The use of gene therapy appears promising in animal models of vestibular dysfunction.
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Silva SA, Maass JC. p27 Kip1 down-regulation as achieved by two clinically feasible means did not induce proliferation of supporting cells in the rat neonatal cochlea in vivo. Hear Res 2018; 373:10-22. [PMID: 30578960 DOI: 10.1016/j.heares.2018.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 11/27/2018] [Accepted: 12/04/2018] [Indexed: 12/24/2022]
Abstract
In mammals, the cochlear sensory epithelium becomes quiescent early during development. After the first postnatal week, there is no cell replacement or proliferation, and severe damage leads to permanent deafness. Supporting cells' trans-differentiation has been suggested as a way to regenerate cochlear hair cells after damage. However, they are also needed for proper functionality. Cdkn1b (p27Kip1) participates in the cochlear terminal mitosis state achieved during development. Its expression is maintained in adult supporting cells and its postnatal deletion has induced cochlear proliferation in vitro and in vivo. Therefore, its manipulation has been proposed as a feasible way to induce proliferation of supporting cells after birth. Nevertheless, the literature is scarce regarding feasible methods to directly decrease p27Kip1 in the clinical domain. The effects of p27Kip1 knockdown using viral vectors are not completely elucidated and no pharmacological approaches to decrease p27Kip1 in the cochlea have been tested in vivo before. This study explores the ability of p27Kip1 messenger knockdown and pharmacological transcriptional inhibition to induce proliferation of supporting cells in the P0 neonatal rat cochlea in vivo. Respectively, lentiviral vectors transducing shRNA against p27Kip1 were administered into the scala media or Alsterpaullone 2-Cyanoethyl into the round window niche. Cell markers and gene expression were assessed through immunostaining and qRT-PCR. Despite both methods significantly decreasing p27Kip1 expression in vivo, signs of toxicity in the organ of Corti were not found; however, relevant proliferation was not found either. Finally, cochlear damage was added to increase the response in vitro, achieving only a mild to moderate proliferation induction. We conclude that our approaches were not able to stimulate the recall of supporting cell proliferation despite significantly decreased p27Kip1 levels in vivo. Considering the evaluation of the cochlea at a very responsive stage, we propose that the level of isolated modification of p27Kip1 expression in living mammals achievable through these approaches is insufficient to induce proliferation of supporting cells. Future proliferation induction experiments in the cochlea should study other methods and genes.
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Affiliation(s)
- Sebastián A Silva
- Department of Otolaryngology, Hospital Clínico Universidad de Chile and Interdisciplinary Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Av. Independencia 1027, 8380453, Independencia, Santiago, Chile
| | - Juan C Maass
- Department of Otolaryngology, Hospital Clínico Universidad de Chile and Interdisciplinary Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Av. Independencia 1027, 8380453, Independencia, Santiago, Chile; Department of Otolaryngology, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana-Universidad del Desarrollo, Av. Vitacura 5951, 7650568, Vitacura, Santiago, Chile.
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Glueckert R, Johnson Chacko L, Rask-Andersen H, Liu W, Handschuh S, Schrott-Fischer A. Anatomical basis of drug delivery to the inner ear. Hear Res 2018; 368:10-27. [PMID: 30442227 DOI: 10.1016/j.heares.2018.06.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 06/16/2018] [Accepted: 06/25/2018] [Indexed: 12/19/2022]
Abstract
The isolated anatomical position and blood-labyrinth barrier hampers systemic drug delivery to the mammalian inner ear. Intratympanic placement of drugs and permeation via the round- and oval window are established methods for local pharmaceutical treatment. Mechanisms of drug uptake and pathways for distribution within the inner ear are hard to predict. The complex microanatomy with fluid-filled spaces separated by tight- and leaky barriers compose various compartments that connect via active and passive transport mechanisms. Here we provide a review on the inner ear architecture at light- and electron microscopy level, relevant for drug delivery. Focus is laid on the human inner ear architecture. Some new data add information on the human inner ear fluid spaces generated with high resolution microcomputed tomography at 15 μm resolution. Perilymphatic spaces are connected with the central modiolus by active transport mechanisms of mesothelial cells that provide access to spiral ganglion neurons. Reports on leaky barriers between scala tympani and the so-called cortilymph compartment likely open the best path for hair cell targeting. The complex barrier system of tight junction proteins such as occludins, claudins and tricellulin isolates the endolymphatic space for most drugs. Comparison of relevant differences of barriers, target cells and cell types involved in drug spread between main animal models and humans shall provide some translational aspects for inner ear drug applications.
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Affiliation(s)
- R Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria; University Clinics Innsbruck, Tirol Kliniken, University Clinic for Ear, Nose and Throat Medicine Innsbruck, Austria.
| | - L Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - H Rask-Andersen
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
| | - W Liu
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
| | - S Handschuh
- VetImaging, VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - A Schrott-Fischer
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
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