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Holt JR, Fettiplace R, Müller U. Sensory transduction in auditory hair cells-PIEZOs can't touch this. J Gen Physiol 2024; 156:e202413585. [PMID: 38727631 PMCID: PMC11090049 DOI: 10.1085/jgp.202413585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2024] Open
Abstract
In this Viewpoint, Holt, Fettiplace, and Müller weigh the evidence supporting a role for PIEZO and TMC channels in mechanosensory transduction in inner ear hair cells.
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Affiliation(s)
- Jeffrey R. Holt
- Departments of Otolaryngology and Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Robert Fettiplace
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Beurg M, Schwalbach ET, Fettiplace R. LHFPL5 is a key element in force transmission from the tip link to the hair cell mechanotransducer channel. Proc Natl Acad Sci U S A 2024; 121:e2318270121. [PMID: 38194445 PMCID: PMC10801851 DOI: 10.1073/pnas.2318270121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 11/30/2023] [Indexed: 01/11/2024] Open
Abstract
During auditory transduction, sound-evoked vibrations of the hair cell stereociliary bundles open mechanotransducer (MET) ion channels via tip links extending from one stereocilium to its neighbor. How tension in the tip link is delivered to the channel is not fully understood. The MET channel comprises a pore-forming subunit, transmembrane channel-like protein (TMC1 or TMC2), aided by several accessory proteins, including LHFPL5 (lipoma HMGIC fusion partner-like 5). We investigated the role of LHFPL5 in transduction by comparing MET channel activation in outer hair cells of Lhfpl5-/- knockout mice with those in Lhfpl5+/- heterozygotes. The 10 to 90 percent working range of transduction in Tmc1+/+; Lhfpl5+/- was 52 nm, from which the single-channel gating force, Z, was evaluated as 0.34 pN. However, in Tmc1+/+; Lhfpl5-/- mice, the working range increased to 123 nm and Z more than halved to 0.13 pN, indicating reduced sensitivity. Tip link tension is thought to activate the channel via a gating spring, whose stiffness is inferred from the stiffness change on tip link destruction. The gating stiffness was ~40 percent of the total bundle stiffness in wild type but was virtually abolished in Lhfpl5-/-, implicating LHFPL5 as a principal component of the gating spring. The mutation Tmc1 p.D569N reduced the LHFPL5 immunolabeling in the stereocilia and like Lhfpl5-/- doubled the MET working range, but other deafness mutations had no effect on the dynamic range. We conclude that tip-link tension is transmitted to the channel primarily via LHFPL5; residual activation without LHFPL5 may occur by direct interaction between PCDH15 and TMC1.
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Affiliation(s)
- Maryline Beurg
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
| | - Evan Travis Schwalbach
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
| | - Robert Fettiplace
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
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Luo Y, Wu K, Zhang X, Wang H, Wang Q. Genetic correction of induced pluripotent stem cells from a DFNA36 patient results in morphologic and functional recovery of derived hair cell-like cells. Stem Cell Res Ther 2024; 15:4. [PMID: 38167128 PMCID: PMC10763492 DOI: 10.1186/s13287-023-03617-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND TMC1 is one of the most common deafness genes causing DFNA36. Patient-derived human induced pluripotent stem cells (iPSCs) provide an opportunity to modelling diseases. TMC1 p.M418K mutation in human is orthologous to Beethoven mice. Here, we investigated the differentiation, morphology and electrophysiological properties of hair cell-like cells (HC-like cells) derived from DFNA36 patient. METHODS Inner ear HC-like cells were induced from iPSCs derived from DFNA36 (TMC1 p.M418K) patient (M+/-), normal control (M+/+) and genetic corrected iPSCs (M+/C). Immunofluorescence, scanning electron microscopy and whole-cell patch-clamp were used to study the mechanism and influence of TMC1 p.M418K mutation. RESULTS In this study we successfully generated HC-like cells from iPSCs with three different genotypes. HC-like cells from M+/- showed defected morphology of microvilli and physiological properties compared to M+/+. HC-like cells from M+/C showed recovery in morphology of microvilli and physiological properties. CONCLUSIONS Our results indicate that TMC1 p.M418K mutation didn't influence inner ear hair cell differentiation but the morphology of microvilli and electrophysiological properties and gene correction induced recovery. CRISPR/Cas9 gene therapy is feasible in human patient with TMC1 p.M418K mutation.
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Affiliation(s)
- Yi Luo
- Department of Audiology and Vestibular Medicine, Senior Department of Otolaryngology, Head and Neck Surgery, Chinese PLA Institute of Otolaryngology, the Sixth Medical Center of PLA General Hospital, 6 Fucheng Road, Beijing, 100048, China
- National Clinical Research Center for Otolaryngologic Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China
- Chinese PLA Medical School, 28 Fuxing Road, Beijing, 100853, China
| | - Kaiwen Wu
- Department of Audiology and Vestibular Medicine, Senior Department of Otolaryngology, Head and Neck Surgery, Chinese PLA Institute of Otolaryngology, the Sixth Medical Center of PLA General Hospital, 6 Fucheng Road, Beijing, 100048, China
- National Clinical Research Center for Otolaryngologic Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China
| | - Xiaolong Zhang
- Department of Audiology and Vestibular Medicine, Senior Department of Otolaryngology, Head and Neck Surgery, Chinese PLA Institute of Otolaryngology, the Sixth Medical Center of PLA General Hospital, 6 Fucheng Road, Beijing, 100048, China
- National Clinical Research Center for Otolaryngologic Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China
| | - Hongyang Wang
- Department of Audiology and Vestibular Medicine, Senior Department of Otolaryngology, Head and Neck Surgery, Chinese PLA Institute of Otolaryngology, the Sixth Medical Center of PLA General Hospital, 6 Fucheng Road, Beijing, 100048, China.
- National Clinical Research Center for Otolaryngologic Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China.
| | - Qiuju Wang
- Department of Audiology and Vestibular Medicine, Senior Department of Otolaryngology, Head and Neck Surgery, Chinese PLA Institute of Otolaryngology, the Sixth Medical Center of PLA General Hospital, 6 Fucheng Road, Beijing, 100048, China.
- National Clinical Research Center for Otolaryngologic Diseases, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China.
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Li X, Ren M, Gu Y, Zhu T, Zhang Y, Li J, Li C, Wang G, Song L, Bi Z, Liu Z. In situ regeneration of inner hair cells in the damaged cochlea by temporally regulated co-expression of Atoh1 and Tbx2. Development 2023; 150:dev201888. [PMID: 38078650 DOI: 10.1242/dev.201888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 11/02/2023] [Indexed: 12/18/2023]
Abstract
Cochlear inner hair cells (IHCs) are primary sound receptors, and are therefore a target for developing treatments for hearing impairment. IHC regeneration in vivo has been widely attempted, although not yet in the IHC-damaged cochlea. Moreover, the extent to which new IHCs resemble wild-type IHCs remains unclear, as is the ability of new IHCs to improve hearing. Here, we have developed an in vivo mouse model wherein wild-type IHCs were pre-damaged and nonsensory supporting cells were transformed into IHCs by ectopically expressing Atoh1 transiently and Tbx2 permanently. Notably, the new IHCs expressed the functional marker vGlut3 and presented similar transcriptomic and electrophysiological properties to wild-type IHCs. Furthermore, the formation efficiency and maturity of new IHCs were higher than those previously reported, although marked hearing improvement was not achieved, at least partly due to defective mechanoelectrical transduction (MET) in new IHCs. Thus, we have successfully regenerated new IHCs resembling wild-type IHCs in many respects in the damaged cochlea. Our findings suggest that the defective MET is a critical barrier that prevents the restoration of hearing capacity and should thus facilitate future IHC regeneration studies.
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Affiliation(s)
- Xiang Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Minhui Ren
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunpeng Gu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tong Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu Zhang
- Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
| | - Jie Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Chao Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Guangqin Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lei Song
- Department of Otolaryngology-Head and Neck Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
- Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200125, China
| | - Zhenghong Bi
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhiyong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 201210, China
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Cho SH, Yun Y, Lee DH, Cha JH, Lee SM, Lee J, Suh MH, Lee JH, Oh SH, Park MK, Lee SY. Novel autosomal dominant TMC1 variants linked to hearing loss: insight into protein-lipid interactions. BMC Med Genomics 2023; 16:320. [PMID: 38066485 PMCID: PMC10704677 DOI: 10.1186/s12920-023-01766-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND TMC1, which encodes transmembrane channel-like protein 1, forms the mechanoelectrical transduction (MET) channel in auditory hair cells, necessary for auditory function. TMC1 variants are known to cause autosomal dominant (DFNA36) and autosomal recessive (DFNB7/11) non-syndromic hearing loss, but only a handful of TMC1 variants underlying DFNA36 have been reported, hampering analysis of genotype-phenotype correlations. METHODS In this study, we retrospectively reviewed 338 probands in an in-house database of genetic hearing loss, evaluating the clinical phenotypes and genotypes of novel TMC1 variants associated with DFNA36. To analyze the structural impact of these variants, we generated two structural models of human TMC1, utilizing the Cryo-EM structure of C. elegans TMC1 as a template and AlphaFold protein structure database. Specifically, the lipid bilayer-embedded protein database was used to construct membrane-embedded models of TMC1. We then examined the effect of TMC1 variants on intramolecular interactions and predicted their potential pathogenicity. RESULTS We identified two novel TMC1 variants related to DFNA36 (c.1256T > C:p.Phe419Ser and c.1444T > C:p.Trp482Arg). The affected subjects had bilateral, moderate, late-onset, progressive sensorineural hearing loss with a down-sloping configuration. The Phe419 residue located in the transmembrane domain 4 of TMC1 faces outward towards the channel pore and is in close proximity to the hydrophobic tail of the lipid bilayer. The non-polar-to-polar variant (p.Phe419Ser) alters the hydrophobicity in the membrane, compromising protein-lipid interactions. On the other hand, the Trp482 residue located in the extracellular linker region between transmembrane domains 5 and 6 is anchored to the membrane interfaces via its aromatic rings, mediating several molecular interactions that stabilize the structure of TMC1. This type of aromatic ring-based anchoring is also observed in homologous transmembrane proteins such as OSCA1.2. Conversely, the substitution of Trp with Arg (Trp482Arg) disrupts the cation-π interaction with phospholipids located in the outer leaflet of the phospholipid bilayer, destabilizing protein-lipid interactions. Additionally, Trp482Arg collapses the CH-π interaction between Trp482 and Pro511, possibly reducing the overall stability of the protein. In parallel with the molecular modeling, the two mutants degraded significantly faster compared to the wild-type protein, compromising protein stability. CONCLUSIONS This results expand the genetic spectrum of disease-causing TMC1 variants related to DFNA36 and provide insight into TMC1 transmembrane protein-lipid interactions.
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Affiliation(s)
- Sung Ho Cho
- Seoul National University College of Medicine, Seoul, South Korea
| | - Yejin Yun
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - Dae Hee Lee
- CTCELLS, Inc, 21, Yuseong-daero, 1205beon-gil, Yuseong-gu, Daejeon, Republic of Korea
| | - Joo Hyun Cha
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - So Min Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - Jehyun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - Myung Hwan Suh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - Jun Ho Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - Seung-Ha Oh
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea
| | - Moo Kyun Park
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea.
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, South Korea.
| | - Sang-Yeon Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-Gu, Daehak-Ro, 101, Seoul, South Korea.
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul, South Korea.
- Department of Genomic Medicine, Precision Medicine & Rare Disease Center, Seoul, South Korea.
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Wang ZH, Zhao W, Combs CA, Zhang F, Knutson JR, Lilly MA, Xu H. Mechanical stimulation from the surrounding tissue activates mitochondrial energy metabolism in Drosophila differentiating germ cells. Dev Cell 2023; 58:2249-2260.e9. [PMID: 37647895 PMCID: PMC10843713 DOI: 10.1016/j.devcel.2023.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/24/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023]
Abstract
In multicellular lives, the differentiation of stem cells and progenitor cells is often accompanied by a transition from glycolysis to mitochondrial oxidative phosphorylation (OXPHOS). However, the underlying mechanism of this metabolic transition remains largely unknown. In this study, we investigate the role of mechanical stress in activating OXPHOS during differentiation of the female germline cyst in Drosophila. We demonstrate that the surrounding somatic cells flatten the 16-cell differentiating cyst, resulting in an increase of the membrane tension of germ cells inside the cyst. This mechanical stress is necessary to maintain cytosolic Ca2+ concentration in germ cells through a mechanically activated channel, transmembrane channel-like. The sustained cytosolic Ca2+ triggers a CaMKI-Fray-JNK signaling relay, leading to the transcriptional activation of OXPHOS in differentiating cysts. Our findings demonstrate a molecular link between cell mechanics and mitochondrial energy metabolism, with implications for other developmentally orchestrated metabolic transitions in mammals.
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Affiliation(s)
- Zong-Heng Wang
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wenjing Zhao
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christian A Combs
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Fan Zhang
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jay R Knutson
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mary A Lilly
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hong Xu
- National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Tisi A, Palaniappan S, Maccarrone M. Advanced Omics Techniques for Understanding Cochlear Genome, Epigenome, and Transcriptome in Health and Disease. Biomolecules 2023; 13:1534. [PMID: 37892216 PMCID: PMC10605747 DOI: 10.3390/biom13101534] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Advanced genomics, transcriptomics, and epigenomics techniques are providing unprecedented insights into the understanding of the molecular underpinnings of the central nervous system, including the neuro-sensory cochlea of the inner ear. Here, we report for the first time a comprehensive and updated overview of the most advanced omics techniques for the study of nucleic acids and their applications in cochlear research. We describe the available in vitro and in vivo models for hearing research and the principles of genomics, transcriptomics, and epigenomics, alongside their most advanced technologies (like single-cell omics and spatial omics), which allow for the investigation of the molecular events that occur at a single-cell resolution while retaining the spatial information.
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Affiliation(s)
- Annamaria Tisi
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy;
| | - Sakthimala Palaniappan
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy;
| | - Mauro Maccarrone
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, 67100 L’Aquila, Italy;
- Laboratory of Lipid Neurochemistry, European Center for Brain Research (CERC), Santa Lucia Foundation IRCCS, 00143 Rome, Italy
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Petit C, Bonnet C, Safieddine S. Deafness: from genetic architecture to gene therapy. Nat Rev Genet 2023; 24:665-686. [PMID: 37173518 DOI: 10.1038/s41576-023-00597-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2023] [Indexed: 05/15/2023]
Abstract
Progress in deciphering the genetic architecture of human sensorineural hearing impairment (SNHI) or loss, and multidisciplinary studies of mouse models, have led to the elucidation of the molecular mechanisms underlying auditory system function, primarily in the cochlea, the mammalian hearing organ. These studies have provided unparalleled insights into the pathophysiological processes involved in SNHI, paving the way for the development of inner-ear gene therapy based on gene replacement, gene augmentation or gene editing. The application of these approaches in preclinical studies over the past decade has highlighted key translational opportunities and challenges for achieving effective, safe and sustained inner-ear gene therapy to prevent or cure monogenic forms of SNHI and associated balance disorders.
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Affiliation(s)
- Christine Petit
- Institut Pasteur, Université Paris Cité, Inserm, Institut de l'Audition, F-75012, Paris, France.
- Collège de France, F-75005, Paris, France.
| | - Crystel Bonnet
- Institut Pasteur, Université Paris Cité, Inserm, Institut de l'Audition, F-75012, Paris, France
| | - Saaïd Safieddine
- Institut Pasteur, Université Paris Cité, Inserm, Institut de l'Audition, F-75012, Paris, France
- Centre National de la Recherche Scientifique, F-75016, Paris, France
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Jung J, Müller U. Mechanoelectrical transduction-related genetic forms of hearing loss. CURRENT OPINION IN PHYSIOLOGY 2023; 32:100632. [PMID: 36936795 PMCID: PMC10022594 DOI: 10.1016/j.cophys.2023.100632] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Hair cells of the mammalian cochlea are specialized mechanosensory cells that convert mechanical stimuli into electrical signals to initiate the neuronal responses that lead to the perception of sound. The mechanoelectrical transduction (MET) machinery of cochlear hair cells is a multimeric protein complex that consists of the pore forming subunits of the MET channel and several essential accessory subunits that are crucial to regulate channel function and render the channel mechanically sensitive. Mutations have been discovered in the genes that encode all known components of the MET machinery. These mutations cause hearing loss with or without vestibular dysfunction. Some mutations also affect other tissues such as the retina. In this brief review, we will summarize gene mutations that affect the MET machinery of hair cells and how the study of the affected genes has illuminated our understanding of the physiological role of the encoded proteins.
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Affiliation(s)
- Jinsei Jung
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Goodman MB, Haswell ES, Vásquez V. Mechanosensitive membrane proteins: Usual and unusual suspects in mediating mechanotransduction. J Gen Physiol 2023; 155:e202213248. [PMID: 36696153 PMCID: PMC9930137 DOI: 10.1085/jgp.202213248] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
This Viewpoint, which accompanies a Special Issue focusing on membrane mechanosensors, discusses unifying and unique features of both established and emerging mechanosensitive (MS) membrane proteins, their distribution across protein families and phyla, and current and future challenges in the study of these important proteins and their partners. MS membrane proteins are essential for tissue development, cellular motion, osmotic homeostasis, and sensing external and self-generated mechanical cues like those responsible for touch and proprioception. Though researchers' attention and this Viewpoint focus on a few famous ion channels that are considered the usual suspects as MS mechanosensors, we also discuss some of the more unusual suspects, such as G-protein coupled receptors. As the field continues to grow, so too will the list of proteins suspected to function as mechanosensors and the diversity of known MS membrane proteins.
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Affiliation(s)
- Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
| | - Elizabeth S. Haswell
- Department of Biology, Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO, USA
| | - Valeria Vásquez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
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11
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Calcium signaling and genetic rare diseases: An auditory perspective. Cell Calcium 2023; 110:102702. [PMID: 36791536 DOI: 10.1016/j.ceca.2023.102702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/07/2023]
Abstract
Deafness is a highly heterogeneous disorder which stems, for 50%, from genetic origins. Sensory transduction relies mainly on sensory hair cells of the cochlea, in the inner ear. Calcium is key for the function of these cells and acts as a fundamental signal transduction. Its homeostasis depends on three factors: the calcium influx, through the mechanotransduction channel at the apical pole of the hair cell as well as the voltage-gated calcium channel at the base of the cells; the calcium buffering via Ca2+-binding proteins in the cytoplasm, but also in organelles such as mitochondria and the reticulum endoplasmic mitochondria-associated membranes with specialized proteins; and the calcium extrusion through the Ca-ATPase pump, located all over the plasma membrane. In addition, the synaptic transmission to the central nervous system is also controlled by calcium. Genetic studies of inherited deafness have tremendously helped understand the underlying molecular pathways of calcium signaling. In this review, we discuss these different factors in light of the associated genetic diseases (syndromic and non-syndromic deafness) and the causative genes.
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12
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Sexually dimorphic architecture and function of a mechanosensory circuit in C. elegans. Nat Commun 2022; 13:6825. [PMID: 36369281 PMCID: PMC9652301 DOI: 10.1038/s41467-022-34661-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 11/01/2022] [Indexed: 11/13/2022] Open
Abstract
How sensory perception is processed by the two sexes of an organism is still only partially understood. Despite some evidence for sexual dimorphism in auditory and olfactory perception, whether touch is sensed in a dimorphic manner has not been addressed. Here we find that the neuronal circuit for tail mechanosensation in C. elegans is wired differently in the two sexes and employs a different combination of sex-shared sensory neurons and interneurons in each sex. Reverse genetic screens uncovered cell- and sex-specific functions of the alpha-tubulin mec-12 and the sodium channel tmc-1 in sensory neurons, and of the glutamate receptors nmr-1 and glr-1 in interneurons, revealing the underlying molecular mechanisms that mediate tail mechanosensation. Moreover, we show that only in males, the sex-shared interneuron AVG is strongly activated by tail mechanical stimulation, and accordingly is crucial for their behavioral response. Importantly, sex reversal experiments demonstrate that the sexual identity of AVG determines both the behavioral output of the mechanosensory response and the molecular pathways controlling it. Our results present extensive sexual dimorphism in a mechanosensory circuit at both the cellular and molecular levels.
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Induced Pluripotent Stem Cells, a Stepping Stone to In Vitro Human Models of Hearing Loss. Cells 2022; 11:cells11203331. [PMID: 36291196 PMCID: PMC9600035 DOI: 10.3390/cells11203331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 10/05/2022] [Accepted: 10/14/2022] [Indexed: 11/28/2022] Open
Abstract
Hearing loss is the most prevalent sensorineural impairment in humans. Yet despite very active research, no effective therapy other than the cochlear implant has reached the clinic. Main reasons for this failure are the multifactorial nature of the disorder, its heterogeneity, and a late onset that hinders the identification of etiological factors. Another problem is the lack of human samples such that practically all the work has been conducted on animals. Although highly valuable data have been obtained from such models, there is the risk that inter-species differences exist that may compromise the relevance of the gathered data. Human-based models are therefore direly needed. The irruption of human induced pluripotent stem cell technologies in the field of hearing research offers the possibility to generate an array of otic cell models of human origin; these may enable the identification of guiding signalling cues during inner ear development and of the mechanisms that lead from genetic alterations to pathology. These models will also be extremely valuable when conducting ototoxicity analyses and when exploring new avenues towards regeneration in the inner ear. This review summarises some of the work that has already been conducted with these cells and contemplates future possibilities.
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The conductance and organization of the TMC1-containing mechanotransducer channel complex in auditory hair cells. Proc Natl Acad Sci U S A 2022; 119:e2210849119. [PMID: 36191207 PMCID: PMC9564823 DOI: 10.1073/pnas.2210849119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We studied the role of TMC1 as the central component of the hair cell mechanotransducer (MET) channel by characterizing transduction in mice harboring mutations in the pore region. All Tmc1 mutations reduced the Ca2+ influx into the hair bundle. Two mutations (Tmc1 p.D528N or Tmc1 p.E520Q) also decreased channel conductance and two (Tmc1 p. D569N or Tmc1 p.W554L) lowered expression. These mutations endorse TMC1 as the pore of the MET channel. The MET channel also contains accessory subunits, LHFPL5 and TMIE. MET currents were small in Lhfpl5 or Tmie knockout mice. Nevertheless, MET channels could still be activated by hair bundle displacement; single-channel conductance was unaffected in Lhfpl5−/− but reduced in Tmie−/−, suggesting TMIE likely contributes to the pore. Transmembrane channel-like protein 1 (TMC1) is thought to form the ion-conducting pore of the mechanoelectrical transducer (MET) channel in auditory hair cells. Using single-channel analysis and ionic permeability measurements, we characterized six missense mutations in the purported pore region of mouse TMC1. All mutations reduced the Ca2+ permeability of the MET channel, triggering hair cell apoptosis and deafness. In addition, Tmc1 p.E520Q and Tmc1 p.D528N reduced channel conductance, whereas Tmc1 p.W554L and Tmc1 p.D569N lowered channel expression without affecting the conductance. Tmc1 p.M412K and Tmc1 p.T416K reduced only the Ca2+ permeability. The consequences of these mutations endorse TMC1 as the pore of the MET channel. The accessory subunits, LHFPL5 and TMIE, are thought to be involved in targeting TMC1 to the tips of the stereocilia. We found sufficient expression of TMC1 in outer hair cells of Lhfpl5 and Tmie knockout mice to determine the properties of the channels, which could still be gated by hair bundle displacement. Single-channel conductance was unaffected in Lhfpl5−/− but was reduced in Tmie−/−, implying TMIE very likely contributes to the pore. Both the working range and half-saturation point of the residual MET current in Lhfpl5−/− were substantially increased, suggesting that LHFPL5 is part of the mechanical coupling between the tip-link and the MET channel. Based on counts of numbers of stereocilia per bundle, we estimate that each PCDH15 and LHFPL5 monomer may contact two channels irrespective of location.
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Gene Therapy for Congenital Hearing Loss. CURRENT OTORHINOLARYNGOLOGY REPORTS 2022. [DOI: 10.1007/s40136-022-00427-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Qi J, Fu X, Zhang L, Tan F, Li N, Sun Q, Hu X, He Z, Xia M, Chai R. Current AAV-mediated gene therapy in sensorineural hearing loss. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Abstract
Current estimates suggest that nearly half a billion people worldwide are affected by hearing loss. Because of the major psychological, social, economic, and health ramifications, considerable efforts have been invested in identifying the genes and molecular pathways involved in hearing loss, whether genetic or environmental, to promote prevention, improve rehabilitation, and develop therapeutics. Genomic sequencing technologies have led to the discovery of genes associated with hearing loss. Studies of the transcriptome and epigenome of the inner ear have characterized key regulators and pathways involved in the development of the inner ear and have paved the way for their use in regenerative medicine. In parallel, the immense preclinical success of using viral vectors for gene delivery in animal models of hearing loss has motivated the industry to work on translating such approaches into the clinic. Here, we review the recent advances in the genomics of auditory function and dysfunction, from patient diagnostics to epigenetics and gene therapy.
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Affiliation(s)
- Shahar Taiber
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; ,
| | - Kathleen Gwilliam
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA; ,
| | - Ronna Hertzano
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, Maryland, USA; ,
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; ,
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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Ballesteros A, Swartz KJ. Regulation of membrane homeostasis by TMC1 mechanoelectrical transduction channels is essential for hearing. SCIENCE ADVANCES 2022; 8:eabm5550. [PMID: 35921424 PMCID: PMC9348795 DOI: 10.1126/sciadv.abm5550] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The mechanoelectrical transduction (MET) channel in auditory hair cells converts sound into electrical signals, enabling hearing. Transmembrane-like channel 1 and 2 (TMC1 and TMC2) are implicated in forming the pore of the MET channel. Here, we demonstrate that inhibition of MET channels, breakage of the tip links required for MET, or buffering of intracellular Ca... induces pronounced phosphatidylserine externalization, membrane blebbing, and ectosome release at the hair cell sensory organelle, culminating in the loss of TMC1. Membrane homeostasis triggered by MET channel inhibition requires Tmc1 but not Tmc2, and three deafness-causing mutations in Tmc1 cause constitutive phosphatidylserine externalization that correlates with deafness phenotype. Our results suggest that, in addition to forming the pore of the MET channel, TMC1 is a critical regulator of membrane homeostasis in hair cells, and that Tmc1-related hearing loss may involve alterations in membrane homeostasis.
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Marcovich I, Baer NK, Shubina-Oleinik O, Eclov R, Beard CW, Holt JR. Optimized AAV Vectors for TMC1 Gene Therapy in a Humanized Mouse Model of DFNB7/11. Biomolecules 2022; 12:914. [PMID: 35883470 PMCID: PMC9313133 DOI: 10.3390/biom12070914] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/14/2022] [Accepted: 06/23/2022] [Indexed: 02/08/2023] Open
Abstract
Gene therapy for genetic hearing loss is an emerging therapeutic modality for hearing restoration. However, the approach has not yet been translated into clinical application. To further develop inner-ear gene therapy, we engineered a novel mouse model bearing a human mutation in the transmembrane channel-1 gene (Tmc1) and characterized the auditory phenotype of the mice. TMC1 forms the mechanosensory transduction channel in mice and humans and is necessary for auditory function. We found that mice harboring the equivalent of the human p.N199I mutation (p.N193I) had profound congenital hearing loss due to loss of hair cell sensory transduction. Next, we optimized and screened viral payloads packaged into AAV9-PHP.B capsids. The vectors were injected into the inner ears of Tmc1Δ/Δ mice and the new humanized Tmc1-p.N193I mouse model. Auditory brainstem responses (ABRs), distortion product otoacoustic emissions (DPOAEs), cell survival, and biodistribution were evaluated in the injected mice. We found broad-spectrum, durable recovery of auditory function in Tmc1-p.N193I mice injected with AAV9-PHP.B-CB6-hTMC1-WPRE. ABR and DPOAE thresholds were equivalent to those of wild-type mice across the entire frequency range. Biodistribution analysis revealed viral DNA/RNA in the contralateral ear, brain, and liver but no overt toxicity. We conclude that the AAV9-PHP.B-CB6-hTMC1-WPRE construct may be suitable for further development as a gene therapy reagent for treatment of humans with genetic hearing loss due to recessive TMC1 mutations.
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Affiliation(s)
- Irina Marcovich
- Department of Otolaryngology & Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (I.M.); (N.K.B.); (O.S.-O.)
| | - Nicholas K. Baer
- Department of Otolaryngology & Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (I.M.); (N.K.B.); (O.S.-O.)
| | - Olga Shubina-Oleinik
- Department of Otolaryngology & Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (I.M.); (N.K.B.); (O.S.-O.)
| | - Rachel Eclov
- Audition Therapeutics (BridgeBio Pharma), Raleigh, NC 27607, USA; (R.E.); (C.W.B.)
| | - Clayton W. Beard
- Audition Therapeutics (BridgeBio Pharma), Raleigh, NC 27607, USA; (R.E.); (C.W.B.)
| | - Jeffrey R. Holt
- Department of Otolaryngology & Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (I.M.); (N.K.B.); (O.S.-O.)
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Preventing autosomal-dominant hearing loss in Bth mice with CRISPR/CasRx-based RNA editing. Signal Transduct Target Ther 2022; 7:79. [PMID: 35283480 PMCID: PMC8918553 DOI: 10.1038/s41392-022-00893-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 12/28/2021] [Accepted: 01/03/2022] [Indexed: 12/26/2022] Open
Abstract
AbstractCRISPR/RfxCas13d (CasRx) editing system can specifically and precisely cleave single-strand RNAs, which is a promising treatment for various disorders by downregulation of related gene expression. Here, we tested this RNA-editing approach on Beethoven (Bth) mice, an animal model for human DFNA36 due to a point mutation in Tmc1. We first screened 30 sgRNAs in cell cultures and found that CasRx with sgRNA3 reduced the Tmc1Bth transcript by 90.8%, and the Tmc1 wild type transcript (Tmc1+) by 44.3%. We then injected a newly developed AAV vector (AAV-PHP.eB) based CasRx into the inner ears of neonatal Bth mice, and we found that Tmc1Bth was reduced by 70.2% in 2 weeks with few off-target effects in the whole transcriptome. Consistently, we found improved hair cell survival, rescued hair bundle degeneration, and reduced mechanoelectrical transduction current. Importantly, the hearing performance, measured in both ABR and DPOAE thresholds, was improved significantly in all ages over 8 weeks. We, therefore, have validated the CRISPR/CasRx-based RNA editing strategy in treating autosomal-dominant hearing loss, paving way for its further application in many other hereditary diseases in hearing and beyond.
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22
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Mechanotransduction in mammalian sensory hair cells. Mol Cell Neurosci 2022; 120:103706. [PMID: 35218890 PMCID: PMC9177625 DOI: 10.1016/j.mcn.2022.103706] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 02/14/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
In the inner ear, the auditory and vestibular systems detect and translate sensory information regarding sound and balance. The sensory cells that transform mechanical input into an electrical signal in these systems are called hair cells. A specialized organelle on the apical surface of the hair cells called the hair bundle detects the mechanical signals. Displacement of the hair bundle causes mechanotransduction channels to open. The morphology and organization of the hair bundle, as well as the properties and characteristics of the mechanotransduction process, differ between the different hair cell types in the auditory and vestibular systems. These differences likely contribute to maximizing the transduction of specific signals in each system. This review will discuss the molecules essential for mechanotransduction and the properties of the mechanotransduction process, focusing our attention on recent data and differences between the auditory and vestibular systems.
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Ion channel-related hereditary hearing loss: a narrative review. JOURNAL OF BIO-X RESEARCH 2021. [DOI: 10.1097/jbr.0000000000000108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Botto C, Dalkara D, El-Amraoui A. Progress in Gene Editing Tools and Their Potential for Correcting Mutations Underlying Hearing and Vision Loss. Front Genome Ed 2021; 3:737632. [PMID: 34778871 PMCID: PMC8581640 DOI: 10.3389/fgeed.2021.737632] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/14/2021] [Indexed: 12/12/2022] Open
Abstract
Blindness and deafness are the most frequent sensory disorders in humans. Whatever their cause - genetic, environmental, or due to toxic agents, or aging - the deterioration of these senses is often linked to irreversible damage to the light-sensing photoreceptor cells (blindness) and/or the mechanosensitive hair cells (deafness). Efforts are increasingly focused on preventing disease progression by correcting or replacing the blindness and deafness-causal pathogenic alleles. In recent years, gene replacement therapies for rare monogenic disorders of the retina have given positive results, leading to the marketing of the first gene therapy product for a form of childhood hereditary blindness. Promising results, with a partial restoration of auditory function, have also been reported in preclinical models of human deafness. Silencing approaches, including antisense oligonucleotides, adeno-associated virus (AAV)-mediated microRNA delivery, and genome-editing approaches have also been applied to various genetic forms of blindness and deafness The discovery of new DNA- and RNA-based CRISPR/Cas nucleases, and the new generations of base, prime, and RNA editors offers new possibilities for directly repairing point mutations and therapeutically restoring gene function. Thanks to easy access and immune-privilege status of self-contained compartments, the eye and the ear continue to be at the forefront of developing therapies for genetic diseases. Here, we review the ongoing applications and achievements of this new class of emerging therapeutics in the sensory organs of vision and hearing, highlighting the challenges ahead and the solutions to be overcome for their successful therapeutic application in vivo.
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Affiliation(s)
- Catherine Botto
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
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Qiu S, Zhao W, Gao X, Li D, Wang W, Gao B, Han W, Yang S, Dai P, Cao P, Yuan Y. Syndromic Deafness Gene ATP6V1B2 Controls Degeneration of Spiral Ganglion Neurons Through Modulating Proton Flux. Front Cell Dev Biol 2021; 9:742714. [PMID: 34746137 PMCID: PMC8568048 DOI: 10.3389/fcell.2021.742714] [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] [Received: 07/16/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
ATP6V1B2 encodes the V1B2 subunit in V-ATPase, a proton pump responsible for the acidification of lysosomes. Mutations in this gene cause DDOD syndrome, DOORS syndrome, and Zimmermann-Laband syndrome, which share overlapping feature of congenital sensorineural deafness, onychodystrophy, and different extents of intellectual disability without or with epilepsy. However, the underlying mechanisms remain unclear. To investigate the pathological role of mutant ATP6V1B2 in the auditory system, we evaluated auditory brainstem response, distortion product otoacoustic emissions, in a transgenic line of mice carrying c.1516 C > T (p.Arg506∗) in Atp6v1b2, Atp6v1b2 Arg506*/Arg506* . To explore the pathogenic mechanism of neurodegeneration in the auditory pathway, immunostaining, western blotting, and RNAscope analyses were performed in Atp6v1b2Arg506*/Arg506* mice. The Atp6v1b2Arg506*/Arg506* mice showed hidden hearing loss (HHL) at early stages and developed late-onset hearing loss. We observed increased transcription of Atp6v1b1 in hair cells of Atp6v1b2Arg506*/Arg506* mice and inferred that Atp6v1b1 compensated for the Atp6v1b2 dysfunction by increasing its own transcription level. Genetic compensation in hair cells explains the milder hearing impairment in Atp6v1b2Arg506*/Arg506* mice. Apoptosis activated by lysosomal dysfunction and the subsequent blockade of autophagic flux induced the degeneration of spiral ganglion neurons and further impaired the hearing. Intraperitoneal administration of the apoptosis inhibitor, BIP-V5, improved both phenotypical and pathological outcomes in two live mutant mice. Based on the pathogenesis underlying hearing loss in Atp6v1b2-related syndromes, systemic drug administration to inhibit apoptosis might be an option for restoring the function of spiral ganglion neurons and promoting hearing, which provides a direction for future treatment.
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Affiliation(s)
- Shiwei Qiu
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China.,The Institute of Audiology and Balance Science, Artificial Auditory Laboratory of Jiangsu Province, Xuzhou Medical University, Xuzhou, China
| | - Weihao Zhao
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China.,Department of Otolaryngology General Hospital of Tibet Military Region, Lhasa, China
| | - Xue Gao
- Department of Otolaryngology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Dapeng Li
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Weiqian Wang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Bo Gao
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Weiju Han
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Shiming Yang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Pu Dai
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
| | - Peng Cao
- National Institute of Biological Sciences, Beijing, China
| | - Yongyi Yuan
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology, Genetic Testing Center for Deafness, Chinese PLA General Hospital; National Clinical Research Center for Otolaryngologic Diseases; Key Lab of Hearing Impairment Science of Ministry of Education; Key Lab of Hearing Impairment Prevention and Treatment of Beijing, Beijing, China
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Lee J, Kawai K, Holt JR, Géléoc GSG. Sensory transduction is required for normal development and maturation of cochlear inner hair cell synapses. eLife 2021; 10:e69433. [PMID: 34734805 PMCID: PMC8598158 DOI: 10.7554/elife.69433] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 11/01/2021] [Indexed: 12/23/2022] Open
Abstract
Acoustic overexposure and aging can damage auditory synapses in the inner ear by a process known as synaptopathy. These insults may also damage hair bundles and the sensory transduction apparatus in auditory hair cells. However, a connection between sensory transduction and synaptopathy has not been established. To evaluate potential contributions of sensory transduction to synapse formation and development, we assessed inner hair cell synapses in several genetic models of dysfunctional sensory transduction, including mice lacking transmembrane channel-like (Tmc) 1, Tmc2, or both, in Beethoven mice which carry a dominant Tmc1 mutation and in Spinner mice which carry a recessive mutation in transmembrane inner ear (Tmie). Our analyses reveal loss of synapses in the absence of sensory transduction and preservation of synapses in Tmc1-null mice following restoration of sensory transduction via Tmc1 gene therapy. These results provide insight into the requirement of sensory transduction for hair cell synapse development and maturation.
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Affiliation(s)
- John Lee
- Speech and Hearing Bioscience & Technology Program, Division of Medical Sciences, Harvard UniversityBostonUnited States
- Department of Otolaryngology, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Kosuke Kawai
- Department of Otolaryngology, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Jeffrey R Holt
- Department of Otolaryngology, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
- Department of Neurology, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Gwenaëlle SG Géléoc
- Department of Otolaryngology, Boston Children’s Hospital and Harvard Medical SchoolBostonUnited States
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Yoshimura H, Nishio S, Usami S. Milestones toward cochlear gene therapy for patients with hereditary hearing loss. Laryngoscope Investig Otolaryngol 2021; 6:958-967. [PMID: 34693000 PMCID: PMC8513455 DOI: 10.1002/lio2.633] [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: 05/12/2021] [Revised: 06/30/2021] [Accepted: 07/28/2021] [Indexed: 02/05/2023] Open
Abstract
A number of genes are reportedly responsible for hereditary hearing loss, which accounts for over 50% of all congenital hearing loss cases. Recent advances in genetic testing have enabled the identification of pathogenic variants in many cases, and systems have been developed to provide personalized treatment based on etiology. Gene therapy is expected to become an unprecedented curative treatment. Several reports have demonstrated the successful use of cochlear gene therapy to restore auditory function in mouse models of genetic deafness; however, many hurdles remain to its clinical application in humans. Herein, we focus on the frequency of deafness genes in patients with congenital and late-onset progressive hearing loss and discuss the following points regarding which genes need to be targeted to efficiently proceed with clinical application: (a) which cells' genes are expressed within the cochlea, (b) whether gene transfer to the targeted cells is possible using vectors such as adeno-associated virus, (c) what phenotype of hearing loss in patients is exhibited, and (d) whether mouse models exist to verify the effectiveness of treatment. Moreover, at the start of clinical application, gene therapy in combination with cochlear implantation may be useful for cases of progressive hearing loss.
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Affiliation(s)
- Hidekane Yoshimura
- Department of OtorhinolaryngologyShinshu University School of MedicineMatsumotoNaganoJapan
| | - Shin‐Ya Nishio
- Department of Hearing Implant SciencesShinshu University School of MedicineMatsumotoNaganoJapan
| | - Shin‐Ichi Usami
- Department of Hearing Implant SciencesShinshu University School of MedicineMatsumotoNaganoJapan
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Prevalence and clinical features of autosomal dominant and recessive TMC1-associated hearing loss. Hum Genet 2021; 141:929-937. [PMID: 34523024 PMCID: PMC9034981 DOI: 10.1007/s00439-021-02364-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/02/2021] [Indexed: 12/20/2022]
Abstract
TMC1 is a causative gene for both autosomal dominant non-syndromic hearing loss (DFNA36) and autosomal recessive non-syndromic hearing loss (DFNB7/11). To date, 125 pathogenic variants in TMC1 have been reported. Most of the TMC1 variants are responsible for autosomal recessive hearing loss, with only 8 variants reported as causative for DFNA36. Here, we reported the prevalence of TMC1-associated hearing loss in a large non-syndromic hearing loss cohort of about 12,000 subjects. As a result, we identified 26 probands with TMC1-associated hearing loss, with the estimated prevalence of TMC1-associated hearing loss in the Japanese hearing loss cohort being 0.17% among all patients. Among the 26 probands with TMC1-associated hearing loss, 15 cases were identified from autosomal dominant hearing loss families. Based on the audiometric data from the probands, family members and previously reported cases, we evaluated hearing deterioration for DFNA36 patients. In addition, we performed haplotype analysis for 11 unrelated autosomal dominant hearing loss families carrying the same variant TMC1: NM_138691:c.1627G > A:p.Asp543Asn. The results clearly indicated that the same haplotype was present despite the families being unrelated, supporting the contention that this variant occurred by founder mutation.
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Chen Z, Zhu S, Kindig K, Wang S, Chou SW, Davis RW, Dercoli MR, Weaver H, Stepanyan R, McDermott BM. Tmc proteins are essential for zebrafish hearing where Tmc1 is not obligatory. Hum Mol Genet 2021; 29:2004-2021. [PMID: 32167554 DOI: 10.1093/hmg/ddaa045] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 02/13/2020] [Indexed: 12/19/2022] Open
Abstract
Perception of sound is initiated by mechanically gated ion channels at the tips of stereocilia. Mature mammalian auditory hair cells require transmembrane channel-like 1 (TMC1) for mechanotransduction, and mutations of the cognate genetic sequences result in dominant or recessive heritable deafness forms in humans and mice. In contrast, zebrafish lateral line hair cells, which detect water motion, require Tmc2a and Tmc2b. Here, we use standard and multiplex genome editing in conjunction with functional and behavioral assays to determine the reliance of zebrafish hearing and vestibular organs on Tmc proteins. Surprisingly, our approach using multiple mutant alleles demonstrates that hearing in zebrafish is not dependent on Tmc1, nor is it fully dependent on Tmc2a and Tmc2b. Hearing however is absent in triple-mutant zebrafish that lack Tmc1, Tmc2a and Tmc2b. These outcomes reveal a striking resemblance of Tmc protein reliance in the vestibular sensory epithelia of mammals to the maculae of zebrafish. Moreover, our findings disclose a logic of Tmc use where hearing depends on a complement of Tmc proteins beyond those employed to sense water motion.
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Affiliation(s)
- Zongwei Chen
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Shaoyuan Zhu
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kayla Kindig
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Shengxuan Wang
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Shih-Wei Chou
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Robin Woods Davis
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Michael R Dercoli
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Hannah Weaver
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Ruben Stepanyan
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Brian M McDermott
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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30
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Montell C. Drosophila sensory receptors-a set of molecular Swiss Army Knives. Genetics 2021; 217:1-34. [PMID: 33683373 DOI: 10.1093/genetics/iyaa011] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/17/2020] [Indexed: 01/01/2023] Open
Abstract
Genetic approaches in the fruit fly, Drosophila melanogaster, have led to a major triumph in the field of sensory biology-the discovery of multiple large families of sensory receptors and channels. Some of these families, such as transient receptor potential channels, are conserved from animals ranging from worms to humans, while others, such as "gustatory receptors," "olfactory receptors," and "ionotropic receptors," are restricted to invertebrates. Prior to the identification of sensory receptors in flies, it was widely assumed that these proteins function in just one modality such as vision, smell, taste, hearing, and somatosensation, which includes thermosensation, light, and noxious mechanical touch. By employing a vast combination of genetic, behavioral, electrophysiological, and other approaches in flies, a major concept to emerge is that many sensory receptors are multitaskers. The earliest example of this idea was the discovery that individual transient receptor potential channels function in multiple senses. It is now clear that multitasking is exhibited by other large receptor families including gustatory receptors, ionotropic receptors, epithelial Na+ channels (also referred to as Pickpockets), and even opsins, which were formerly thought to function exclusively as light sensors. Genetic characterizations of these Drosophila receptors and the neurons that express them also reveal the mechanisms through which flies can accurately differentiate between different stimuli even when they activate the same receptor, as well as mechanisms of adaptation, amplification, and sensory integration. The insights gleaned from studies in flies have been highly influential in directing investigations in many other animal models.
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Affiliation(s)
- Craig Montell
- Department of Molecular, Cellular, and Developmental Biology, The Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA
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31
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Liu S, Wang S, Zou L, Xiong W. Mechanisms in cochlear hair cell mechano-electrical transduction for acquisition of sound frequency and intensity. Cell Mol Life Sci 2021; 78:5083-5094. [PMID: 33871677 PMCID: PMC11072359 DOI: 10.1007/s00018-021-03840-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/30/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Sound signals are acquired and digitized in the cochlea by the hair cells that further transmit the coded information to the central auditory pathways. Any defect in hair cell function may induce problems in the auditory system and hearing-based brain function. In the past 2 decades, our understanding of auditory transduction has been substantially deepened because of advances in molecular, structural, and functional studies. Results from these experiments can be perfectly embedded in the previously established profile from anatomical, histological, genetic, and biophysical research. This review aims to summarize the progress on the molecular and cellular mechanisms of the mechano-electrical transduction (MET) channel in the cochlear hair cells, which is involved in the acquisition of sound frequency and intensity-the two major parameters of an acoustic cue. We also discuss recent studies on TMC1, the molecule likely to form the MET channel pore.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
- IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, 1 Qinghuayuan, Beijing, 100084, China.
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32
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New Tmc1 Deafness Mutations Impact Mechanotransduction in Auditory Hair Cells. J Neurosci 2021; 41:4378-4391. [PMID: 33824189 PMCID: PMC8152607 DOI: 10.1523/jneurosci.2537-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 03/19/2021] [Accepted: 03/27/2021] [Indexed: 12/05/2022] Open
Abstract
Transmembrane channel-like protein isoform 1 (TMC1) is a major component of the mechano-electrical transducer (MET) channel in cochlear hair cells and is subject to numerous mutations causing deafness. We report a new dominant human deafness mutation, TMC1 p.T422K, and have characterized the homologous mouse mutant, Tmc1 p.T416K, which caused deafness and outer hair cell (OHC) loss by the fourth postnatal week. MET channels showed decreased Ca2+ permeability and resting open probability, but no change in single-channel conductance or expression. Three adjacent deafness mutations are TMC1 p.L416R, p.G417R, and p.M418K, the last homologous to the mouse Beethoven that exhibits similar channel effects. All substitute a positive for a neutral residue, which could produce charge screening in the channel pore or influence binding of an accessory subunit. Channel properties were compared in mice of both sexes between dominant (Tmc1 p.T416K, Tmc1 p.D569N) and recessive (Tmc1 p.W554L, Tmc1 p.D528N) mutations of residues near the putative pore of the channel. Tmc1 p.W554L and p.D569N exhibit reduced maximum current with no effect on single-channel conductance, implying a smaller number of channels transported to the stereociliary tips; this may stem from impaired TMC1 binding to LHFPL5. Tmc1 p.D528N, located in the pore's narrowest region, uniquely caused large reductions in MET channel conductance and block by dihydrostreptomycin (DHS). For Tmc1 p.T416K and Tmc1 p.D528N, transduction loss occurred between P15 and P20. We propose two mechanisms linking channel mutations and deafness: decreased Ca2+ permeability, common to all mutants, and decreased resting open probability in low Ca2+, confined to dominant mutations. SIGNIFICANCE STATEMENT Transmembrane channel-like protein isoform 1 (TMC1) is thought to be a major component of the mechanotransducer channel in auditory hair cells, but the protein organization and channel structure are still uncertain. We made four mouse lines harboring Tmc1 point mutations that alter channel properties, causing hair cell degeneration and deafness. These include a mouse homolog of a new human deafness mutation pT416K that decreased channel Ca2+ permeability by introducing a positively-charged amino acid in the putative pore. All mutations are consistent with the channel structure predicted from modeling, but only one, p.D528N near the external face of the pore, substantially reduced channel conductance and Ca2+ permeability and virtually abolished block by dihydrostreptomycin (DHS), strongly endorsing its siting within the pore.
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Gu X, Wang D, Xu Z, Wang J, Guo L, Chai R, Li G, Shu Y, Li H. Prevention of acquired sensorineural hearing loss in mice by in vivo Htra2 gene editing. Genome Biol 2021; 22:86. [PMID: 33752742 PMCID: PMC7983387 DOI: 10.1186/s13059-021-02311-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 03/08/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Aging, noise, infection, and ototoxic drugs are the major causes of human acquired sensorineural hearing loss, but treatment options are limited. CRISPR/Cas9 technology has tremendous potential to become a new therapeutic modality for acquired non-inherited sensorineural hearing loss. Here, we develop CRISPR/Cas9 strategies to prevent aminoglycoside-induced deafness, a common type of acquired non-inherited sensorineural hearing loss, via disrupting the Htra2 gene in the inner ear which is involved in apoptosis but has not been investigated in cochlear hair cell protection. RESULTS The results indicate that adeno-associated virus (AAV)-mediated delivery of CRISPR/SpCas9 system ameliorates neomycin-induced apoptosis, promotes hair cell survival, and significantly improves hearing function in neomycin-treated mice. The protective effect of the AAV-CRISPR/Cas9 system in vivo is sustained up to 8 weeks after neomycin exposure. For more efficient delivery of the whole CRISPR/Cas9 system, we also explore the AAV-CRISPR/SaCas9 system to prevent neomycin-induced deafness. The in vivo editing efficiency of the SaCas9 system is 1.73% on average. We observed significant improvement in auditory brainstem response thresholds in the injected ears compared with the non-injected ears. At 4 weeks after neomycin exposure, the protective effect of the AAV-CRISPR/SaCas9 system is still obvious, with the improvement in auditory brainstem response threshold up to 50 dB at 8 kHz. CONCLUSIONS These findings demonstrate the safe and effective prevention of aminoglycoside-induced deafness via Htra2 gene editing and support further development of the CRISPR/Cas9 technology in the treatment of non-inherited hearing loss as well as other non-inherited diseases.
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Affiliation(s)
- Xi Gu
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- Department of Otolaryngology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, 350005 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Daqi Wang
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Zhijiao Xu
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Jinghan Wang
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Luo Guo
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, 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
- Institute for Stem Cell and Regeneration, Chinese Academy of Science, Beijing, China
| | - Genglin Li
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Yilai Shu
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
| | - Huawei Li
- ENT institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200031 China
- Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032 China
- NHC Key Laboratory of Hearing Medicine (Fudan University), Shanghai, 200031 China
- The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032 China
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Bankoti K, Generotti C, Hwa T, Wang L, O'Malley BW, Li D. Advances and challenges in adeno-associated viral inner-ear gene therapy for sensorineural hearing loss. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 21:209-236. [PMID: 33850952 PMCID: PMC8010215 DOI: 10.1016/j.omtm.2021.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
There is growing attention and effort focused on treating the root cause of sensorineural hearing loss rather than managing associated secondary characteristic features. With recent substantial advances in understanding sensorineural hearing-loss mechanisms, gene delivery has emerged as a promising strategy for the biological treatment of hearing loss associated with genetic dysfunction. There are several successful and promising proof-of-principle examples of transgene deliveries in animal models; however, there remains substantial further progress to be made in these avenues before realizing their clinical application in humans. Herein, we review different aspects of development, ongoing preclinical studies, and challenges to the clinical transition of transgene delivery of the inner ear toward the restoration of lost auditory and vestibular function.
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Affiliation(s)
- Kamakshi Bankoti
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charles Generotti
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tiffany Hwa
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lili Wang
- Department of Medicine, Gene Therapy Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bert W O'Malley
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daqing Li
- Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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35
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Wu J, Solanes P, Nist-Lund C, Spataro S, Shubina-Oleinik O, Marcovich I, Goldberg H, Schneider BL, Holt JR. Single and Dual Vector Gene Therapy with AAV9-PHP.B Rescues Hearing in Tmc1 Mutant Mice. Mol Ther 2021; 29:973-988. [PMID: 33212302 PMCID: PMC7934577 DOI: 10.1016/j.ymthe.2020.11.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/03/2020] [Accepted: 11/11/2020] [Indexed: 01/19/2023] Open
Abstract
AAV-mediated gene therapy is a promising approach for treating genetic hearing loss. Replacement or editing of the Tmc1 gene, encoding hair cell mechanosensory ion channels, is effective for hearing restoration in mice with some limitations. Efficient rescue of outer hair cell function and lack of hearing recovery with later-stage treatment remain issues to be solved. Exogenous genes delivered with the adeno-associated virus (AAV)9-PHP.B capsid via the utricle transduce both inner and outer hair cells of the mouse cochlea with high efficacy. Here, we demonstrate that AAV9-PHP.B gene therapy can promote hair cell survival and successfully rescues hearing in three distinct mouse models of hearing loss. Tmc1 replacement with AAV9-PHP.B in a Tmc1 knockout mouse rescues hearing and promotes hair cell survival with equal efficacy in inner and outer hair cells. The same treatment in a recessive Tmc1 hearing-loss model, Baringo, partially recovers hearing even with later-stage treatment. Finally, dual delivery of Streptococcus pyogenes Cas9 (SpCas9) and guide RNA (gRNA) in separate AAV9-PHP.B vectors selectively disrupts a dominant Tmc1 allele and preserves hearing in Beethoven mice, a model of dominant, progressive hearing loss. Tmc1-targeted gene therapies using single or dual AAV9-PHP.B vectors offer potent and versatile approaches for treating dominant and recessive deafness.
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Affiliation(s)
- Jason Wu
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Paola Solanes
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, 1015 Lausanne, Switzerland
| | - Carl Nist-Lund
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Sofia Spataro
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, 1015 Lausanne, Switzerland
| | - Olga Shubina-Oleinik
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Irina Marcovich
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Hannah Goldberg
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Station 19, 1015 Lausanne, Switzerland; Bertarelli Foundation Gene Therapy Platform, Ecole Polytechnique Fédérale de Lausanne, Ch. des Mines 9, 1202 Geneva, Switzerland
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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36
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Li S, Yan Z. Mechanotransduction Ion Channels in Hearing and Touch. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1349:371-385. [DOI: 10.1007/978-981-16-4254-8_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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37
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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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38
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Lewis MA, Di Domenico F, Ingham NJ, Prosser HM, Steel KP. Hearing impairment due to Mir183/96/182 mutations suggests both loss and gain of function effects. Dis Model Mech 2020; 14:dmm.047225. [PMID: 33318051 PMCID: PMC7903918 DOI: 10.1242/dmm.047225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 12/03/2020] [Indexed: 01/13/2023] Open
Abstract
The microRNA miR-96 is important for hearing, as point mutations in humans and mice result in dominant progressive hearing loss. Mir96 is expressed in sensory cells along with Mir182 and Mir183, but the roles of these closely-linked microRNAs are as yet unknown. Here we analyse mice carrying null alleles of Mir182, and of Mir183 and Mir96 together to investigate their roles in hearing. We found that Mir183/96 heterozygous mice had normal hearing and homozygotes were completely deaf with abnormal hair cell stereocilia bundles and reduced numbers of inner hair cell synapses at four weeks old. Mir182 knockout mice developed normal hearing then exhibited progressive hearing loss. Our transcriptional analyses revealed significant changes in a range of other genes, but surprisingly there were fewer genes with altered expression in the organ of Corti of Mir183/96 null mice compared with our previous findings in Mir96 Dmdo mutants, which have a point mutation in the miR-96 seed region. This suggests the more severe phenotype of Mir96 Dmdo mutants compared with Mir183/96 mutants, including progressive hearing loss in Mir96 Dmdo heterozygotes, is likely to be mediated by the gain of novel target genes in addition to the loss of its normal targets. We propose three mechanisms of action of mutant miRNAs; loss of targets that are normally completely repressed, loss of targets whose transcription is normally buffered by the miRNA, and gain of novel targets. Any of these mechanisms could lead to a partial loss of a robust cellular identity and consequent dysfunction.
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Affiliation(s)
- Morag A Lewis
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | | | - Neil J Ingham
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Haydn M Prosser
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
| | - Karen P Steel
- Wolfson Centre for Age-Related Diseases, King's College London, London, SE1 1UL, UK
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
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39
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Abstract
Sound-induced mechanical stimuli are detected by elaborate mechanosensory transduction (MT) machinery in highly specialized hair cells of the inner ear. Genetic studies of inherited deafness in the past decades have uncovered several molecular constituents of the MT complex, and intense debate has surrounded the molecular identity of the pore-forming subunits. How the MT components function in concert in response to physical stimulation is not fully understood. In this review, we summarize and discuss multiple lines of evidence supporting the hypothesis that transmembrane channel-like 1 is a long-sought MT channel subunit. We also review specific roles of other components of the MT complex, including protocadherin 15, cadherin 23, lipoma HMGIC fusion partner-like 5, transmembrane inner ear, calcium and integrin-binding family member 2, and ankyrins. Based on these recent advances, we propose a unifying theory of hair cell MT that may reconcile most of the functional discoveries obtained to date. Finally, we discuss key questions that need to be addressed for a comprehensive understanding of hair cell MT at molecular and atomic levels.
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Affiliation(s)
- Wang Zheng
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA;
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40
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Marcovich I, Holt JR. Evolution and function of Tmc genes in mammalian hearing. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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41
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Jia YL, Zhang YJ, Guo D, Li CY, Ma JY, Gao CF, Wu SF. A Mechanosensory Receptor TMC Regulates Ovary Development in the Brown Planthopper Nilaparvata lugens. Front Genet 2020; 11:573603. [PMID: 33193678 PMCID: PMC7649262 DOI: 10.3389/fgene.2020.573603] [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] [Received: 06/17/2020] [Accepted: 09/02/2020] [Indexed: 11/29/2022] Open
Abstract
Transmembrane channel-like (TMC) genes encode a family of evolutionarily conserved membrane proteins. Mutations in the TMC1 and TMC2 cause deafness in humans and mice. However, their functions in insects are is still not well known. Here we cloned three tmc genes, Nltmc3, Nltmc5, and Nltmc7 from brown planthoppers. The predicted amino acid sequences showed high identity with other species homologs and have the characteristic eight or nine transmembrane domains and TMC domain architecture. We detected these three genes in all developmental stages and examined tissues. Interestingly, we found Nltmc3 was highly expressed in the female reproductive organ especially in the oviduct. RNAi-mediated silencing of Nltmc3 substantially decreased the egg-laying number and impaired ovary development. Our results indicate that Nltmc3 has an essential role in the ovary development of brown planthoppers.
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Affiliation(s)
- Ya-Long Jia
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Yi-Jie Zhang
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Di Guo
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Chen-Yu Li
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Jun-Yu Ma
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Cong-Fen Gao
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
| | - Shun-Fan Wu
- College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing, China
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Niggemann P, György B, Chen ZY. Genome and base editing for genetic hearing loss. Hear Res 2020; 394:107958. [PMID: 32334889 PMCID: PMC7415640 DOI: 10.1016/j.heares.2020.107958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 03/18/2020] [Accepted: 03/31/2020] [Indexed: 12/26/2022]
Abstract
Genome editing opens up a new frontier in developing personalized therapeutic solutions. With the unprecedented advance in the discovery and engineering of gene editing nucleases, it has now become potentially feasible to therapeutically influence up to 90% of all human genetic mutations. Hearing loss is one of the most well studied fields from the genetics perspective, with more than one hundred identified deafness genes. Novel viral and non-viral vectors have been established as safe and efficient modalities to deliver transgenes into cells of the cochlea and to the vestibular system in animal models. Recent studies demonstrated proof-of-concept for therapeutic genome and base editing in the mammalian inner ear and preclinical development is ongoing. This review summarizes important advances and future challenges for this transformative therapeutic modality for genetic and non-genetic hearing loss.
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Affiliation(s)
- Philipp Niggemann
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Bence György
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland.
| | - 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, 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA, 02114, USA.
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43
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Gene therapy development in hearing research in China. Gene Ther 2020; 27:349-359. [PMID: 32681137 DOI: 10.1038/s41434-020-0177-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/13/2020] [Accepted: 07/08/2020] [Indexed: 12/15/2022]
Abstract
Sensorineural hearing loss, the most common form of hearing impairment, is mainly attributable to genetic mutations or acquired factors, such as aging, noise exposure, and ototoxic drugs. In the field of gene therapy, advances in genetic and physiological studies and profound increases in knowledge regarding the underlying mechanisms have yielded great progress in terms of restoring the auditory function in animal models of deafness. Nonetheless, many challenges associated with the translation from basic research to clinical therapies remain to be overcome before a total restoration of auditory function can be expected. In recent years, Chinese research teams have promoted various developmental efforts in this field, including gene sequencing to identify additional potential loci that cause deafness, studies to elucidate the underlying molecular mechanisms, and research to optimize vectors and delivery routes. In this review, we summarize the state of the field and focus mainly on the progress of gene therapy in animal model studies and the optimization of therapeutic strategies in China.
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Ramzan K, Al-Owain M, Al-Numair NS, Afzal S, Al-Ageel S, Al-Amer S, Al-Baik L, Al-Otaibi GF, Hashem A, Al-Mashharawi E, Basit S, Al-Mazroea AH, Softah A, Sogaty S, Imtiaz F. Identification of TMC1 as a relatively common cause for nonsyndromic hearing loss in the Saudi population. Am J Med Genet B Neuropsychiatr Genet 2020; 183:172-180. [PMID: 31854501 DOI: 10.1002/ajmg.b.32774] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/06/2019] [Accepted: 12/02/2019] [Indexed: 11/11/2022]
Abstract
Hearing loss (HL) is the most common sensory disorder worldwide and genetic factors contribute to approximately half of congenital HL cases. HL is subject to extensive genetic heterogeneity, rendering molecular diagnosis difficult. Mutations of the transmembrane channel-like 1 (TMC1) gene cause hearing defects in humans and mice. The precise function of TMC1 protein in the inner ear is unknown, although it is predicted to be involved in functional maturation of cochlear hair cells. TMC1 mutations result in autosomal recessive (DFNB7/11) and sometimes dominant (DFNA36) nonsyndromic HL. Mutations in TMC1 are responsible for a significant portion of HL, particularly in consanguineous populations. To evaluate the importance of TMC1 mutations in the Saudi population, we used a combination of autozygome-guided candidate gene mutation analysis and targeted next generation sequencing in 366 families with HL previously shown to lack mutations in GJB2. We identified 12 families that carried five causative TMC1 mutations; including three novel (c.362+3A > G; c.758C > T [p.Ser253Phe]; c.1396_1398delACC [p.Asn466del]) and two reported mutations (c.100C > T [p.Arg34Ter]; c.1714G > A [p.Asp572Asn]). Each of the identified recessive mutation was classified as severe, by both age of onset and severity of HL. Similarly, consistent with the previously reported dominant variant p.Asp572Asn, the HL phenotype was progressive. Eight families in our cohort were found to share the pathogenic p.Arg34Ter mutation and linkage disequilibrium was observed between p.Arg34Ter and SNPs investigated. Our results indicate that TMC1 mutations account for about 3.3% (12/366) of Saudi HL cases and that the recurrent TMC1 mutation p.Arg34Ter is likely to be a founder mutation.
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Affiliation(s)
- Khushnooda Ramzan
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mohammed Al-Owain
- Department of Medical Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Nouf S Al-Numair
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Sibtain Afzal
- College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Sarah Al-Ageel
- Department of Otolaryngology Head and Neck Surgery, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Sultan Al-Amer
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Lina Al-Baik
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Ghoson F Al-Otaibi
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Amal Hashem
- Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Eman Al-Mashharawi
- Department of Otolaryngology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Sulman Basit
- Center for Genetics and Inherited Diseases, Taibah University, Al-Madinah, Saudi Arabia
| | - Abdal H Al-Mazroea
- Pediatrics Department, College of Medicine, Taibah University, Al-Madinah, Saudi Arabia
| | - Ameen Softah
- King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Sameera Sogaty
- Medical Genetics Unit, King Fahad Hospital, Jeddah, Saudi Arabia
| | - Faiqa Imtiaz
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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45
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Fetal gene therapy and pharmacotherapy to treat congenital hearing loss and vestibular dysfunction. Hear Res 2020; 394:107931. [PMID: 32173115 DOI: 10.1016/j.heares.2020.107931] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 12/23/2022]
Abstract
Disabling hearing loss is expected to affect over 900 million people worldwide by 2050. The World Health Organization estimates that the annual economic impact of hearing loss globally is US$ 750 billion. The inability to hear may complicate effective interpersonal communication and negatively impact personal and professional relationships. Recent advances in the genetic diagnosis of inner ear disease have keenly focused attention on strategies to restore hearing and balance in individuals with defined gene mutations. Mouse models of human hearing loss serve as the primary approach to test gene therapies and pharmacotherapies. The goal of this review is to articulate the rationale for fetal gene therapy and pharmacotherapy to treat congenital hearing loss and vestibular dysfunction. The differential onset of hearing in mice and humans suggests that a prenatal window of therapeutic efficacy in humans may be optimal to restore sensory function. Mouse studies demonstrating the utility of early fetal intervention in the inner ear show promise. We focus on the modulation of gene expression through two strategies that have successfully treated deafness in animal models and have had clinical success for other conditions in humans: gene replacement and antisense oligonucleotide-mediated modulation of gene expression. The recent establishment of effective therapies targeting the juvenile and adult mouse provide informative counterexamples where intervention in the maturing and fully functional mouse inner ear may be effective. Distillation of the current literature leads to the conclusion that novel therapeutic strategies to treat genetic deafness and imbalance will soon translate to clinical trials.
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46
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Jia Y, Zhao Y, Kusakizako T, Wang Y, Pan C, Zhang Y, Nureki O, Hattori M, Yan Z. TMC1 and TMC2 Proteins Are Pore-Forming Subunits of Mechanosensitive Ion Channels. Neuron 2019; 105:310-321.e3. [PMID: 31761710 DOI: 10.1016/j.neuron.2019.10.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/05/2019] [Accepted: 10/09/2019] [Indexed: 11/28/2022]
Abstract
Transmembrane channel-like (TMC) 1 and 2 are required for the mechanotransduction of mouse inner ear hair cells and localize to the site of mechanotransduction in mouse hair cell stereocilia. However, it remains unclear whether TMC1 and TMC2 are indeed ion channels and whether they can sense mechanical force directly. Here we express TMC1 from the green sea turtle (CmTMC1) and TMC2 from the budgerigar (MuTMC2) in insect cells, purify and reconstitute the proteins, and show that liposome-reconstituted CmTMC1 and MuTMC2 proteins possess ion channel activity. Furthermore, by applying pressure to proteoliposomes, we demonstrate that both CmTMC1 and MuTMC2 proteins can indeed respond to mechanical stimuli. In addition, CmTMC1 mutants corresponding to human hearing loss mutants exhibit reduced or no ion channel activity. Taken together, our results show that the CmTMC1 and MuTMC2 proteins are pore-forming subunits of mechanosensitive ion channels, supporting TMC1 and TMC2 as hair cell transduction channels.
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Affiliation(s)
- Yanyan Jia
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yimeng Zhao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yao Wang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Chengfang Pan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Yuwei Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Department of Neurosurgery at Huashan Hospital, Human Phenome Institute, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai 200438, China.
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47
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Yue X, Sheng Y, Kang L, Xiao R. Distinct functions of TMC channels: a comparative overview. Cell Mol Life Sci 2019; 76:4221-4232. [PMID: 31584127 PMCID: PMC11105308 DOI: 10.1007/s00018-019-03214-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/18/2022]
Abstract
In the past two decades, transmembrane channel-like (TMC) proteins have attracted a significant amount of research interest, because mutations of Tmc1 lead to hereditary deafness. As evolutionarily conserved membrane proteins, TMC proteins are widely involved in diverse sensorimotor functions of many species, such as hearing, chemosensation, egg laying, and food texture detection. Interestingly, recent structural and physiological studies suggest that TMC channels may share a similar membrane topology with the Ca2+-activated Cl- channel TMEM16 and the mechanically activated OSCA1.2/TMEM63 channel. Namely, these channels form dimers and each subunit consists of ten transmembrane segments. Despite this important structural insight, a key question remains: what is the gating mechanism of TMC channels? The major technical hurdle to answer this question is that the reconstitution of TMC proteins as functional ion channels has been challenging in mammalian heterologous systems. Since TMC channels are conserved across taxa, genetic studies of TMC channels in model organisms such as C. elegans, Drosophila, and zebrafish may provide us critical information on the physiological function and regulation of TMCs. Here, we present a comparative overview on the diverse functions of TMC channels in different species.
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Affiliation(s)
- Xiaomin Yue
- Department of Neurosurgery of the First Affiliated Hospital, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Sheng
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA
| | - Lijun Kang
- Department of Neurosurgery of the First Affiliated Hospital, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.
| | - Rui Xiao
- Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, FL, USA.
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL, USA.
- Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
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48
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Liu S, Wang S, Zou L, Li J, Song C, Chen J, Hu Q, Liu L, Huang P, Xiong W. TMC1 is an essential component of a leak channel that modulates tonotopy and excitability of auditory hair cells in mice. eLife 2019; 8:47441. [PMID: 31661074 PMCID: PMC6853638 DOI: 10.7554/elife.47441] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/24/2019] [Indexed: 11/13/2022] Open
Abstract
Hearing sensation relies on the mechano-electrical transducer (MET) channel of cochlear hair cells, in which transmembrane channel-like 1 (TMC1) and transmembrane channel-like 2 (TMC2) have been proposed to be the pore-forming subunits in mammals. TMCs were also found to regulate biological processes other than MET in invertebrates, ranging from sensations to motor function. However, whether TMCs have a non-MET role remains elusive in mammals. Here, we report that in mouse hair cells, TMC1, but not TMC2, provides a background leak conductance, with properties distinct from those of the MET channels. By cysteine substitutions in TMC1, we characterized four amino acids that are required for the leak conductance. The leak conductance is graded in a frequency-dependent manner along the length of the cochlea and is indispensable for action potential firing. Taken together, our results show that TMC1 confers a background leak conductance in cochlear hair cells, which may be critical for the acquisition of sound-frequency and -intensity.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Jie Li
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Chenmeng Song
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Jiaofeng Chen
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Qun Hu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Lian Liu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Pingbo Huang
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China.,State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.,Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
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49
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Müller NIC, Sonntag M, Maraslioglu A, Hirtz JJ, Friauf E. Topographic map refinement and synaptic strengthening of a sound localization circuit require spontaneous peripheral activity. J Physiol 2019; 597:5469-5493. [PMID: 31529505 DOI: 10.1113/jp277757] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 09/13/2019] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Loss of the calcium sensor otoferlin disrupts neurotransmission from inner hair cells. Central auditory nuclei are functionally denervated in otoferlin knockout mice (Otof KOs) via gene ablation confined to the periphery. We employed juvenile and young adult Otof KO mice (postnatal days (P)10-12 and P27-49) as a model for lacking spontaneous activity and deafness, respectively. We studied the impact of peripheral activity on synaptic refinement in the sound localization circuit from the medial nucleus of the trapezoid body (MNTB) to the lateral superior olive (LSO). MNTB in vivo recordings demonstrated drastically reduced spontaneous spiking and deafness in Otof KOs. Juvenile KOs showed impaired synapse elimination and strengthening, manifested by broader MNTB-LSO inputs, imprecise MNTB-LSO topography and weaker MNTB-LSO fibres. The impairments persisted into young adulthood. Further functional refinement after hearing onset was undetected in young adult wild-types. Collectively, activity deprivation confined to peripheral protein loss impairs functional MNTB-LSO refinement during a critical prehearing period. ABSTRACT Circuit refinement is critical for the developing sound localization pathways in the auditory brainstem. In prehearing mice (hearing onset around postnatal day (P)12), spontaneous activity propagates from the periphery to central auditory nuclei. At the glycinergic projection from the medial nucleus of the trapezoid body (MNTB) to the lateral superior olive (LSO) of neonatal mice, super-numerous MNTB fibres innervate a given LSO neuron. Between P4 and P9, MNTB fibres are functionally eliminated, whereas the remaining fibres are strengthened. Little is known about MNTB-LSO circuit refinement after P20. Moreover, MNTB-LSO refinement upon activity deprivation confined to the periphery is largely unexplored. This leaves a considerable knowledge gap, as deprivation often occurs in patients with congenital deafness, e.g. upon mutations in the otoferlin gene (OTOF). Here, we analysed juvenile (P10-12) and young adult (P27-49) otoferlin knockout (Otof KO) mice with respect to MNTB-LSO refinement. MNTB in vivo recordings revealed drastically reduced spontaneous activity and deafness in knockouts (KOs), confirming deprivation. As RNA sequencing revealed Otof absence in the MNTB and LSO of wild-types, Otof loss in KOs is specific to the periphery. Functional denervation impaired MNTB-LSO synapse elimination and strengthening, which was assessed by glutamate uncaging and electrical stimulation. Impaired elimination led to imprecise MNTB-LSO topography. Impaired strengthening was associated with lower quantal content per MNTB fibre. In young adult KOs, the MNTB-LSO circuit remained unrefined. Further functional refinement after P12 appeared absent in wild-types. Collectively, we provide novel insights into functional MNTB-LSO circuit maturation governed by a cochlea-specific protein. The central malfunctions in Otof KOs may have implications for patients with sensorineuronal hearing loss.
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Affiliation(s)
- Nicolas I C Müller
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, D-67663, Kaiserslautern, Germany
| | - Mandy Sonntag
- Paul Flechsig Institute of Brain Research, Faculty of Medicine, University of Leipzig, D-04103, Leipzig, Germany
| | - Ayse Maraslioglu
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, D-67663, Kaiserslautern, Germany
| | - Jan J Hirtz
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, D-67663, Kaiserslautern, Germany.,Physiology of Neuronal Networks, Department of Biology, University of Kaiserslautern, D-67663, Kaiserslautern, Germany
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, D-67663, Kaiserslautern, Germany
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50
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Soler DC, Manikandan M, Gopal SR, Sloan AE, McCormick TS, Stepanyan R. An uncharacterized region within the N-terminus of mouse TMC1 precludes trafficking to plasma membrane in a heterologous cell line. Sci Rep 2019; 9:15263. [PMID: 31649296 PMCID: PMC6813322 DOI: 10.1038/s41598-019-51336-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 09/24/2019] [Indexed: 12/21/2022] Open
Abstract
Mechanotransduction by hair cell stereocilia lies at the heart of sound detection in vertebrates. Considerable effort has been put forth to identify proteins that comprise the hair cell mechanotransduction apparatus. TMC1, a member of the transmembrane channel-like (TMC) family, was identified as a core protein of the mechanotransduction complex in hair cells. However, the inability of TMC1 to traffic through the endoplasmic reticulum in heterologous cellular systems has hindered efforts to characterize its function and fully identify its role in mechanotransduction. We developed a novel approach that allowed for the detection of uncharacterized protein regions, which preclude trafficking to the plasma membrane (PM) in heterologous cells. Tagging N-terminal fragments of TMC1 with Aquaporin 3 (AQP3) and GFP fusion reporter, which intrinsically label PM in HEK293 cells, indicated that residues at the edges of amino acid sequence 138–168 invoke intracellular localization and/or degradation. This signal is able to preclude surface localization of PM protein AQP3 in HEK293 cells. Substitutions of the residues by alanine or serine corroborated that the information determining the intracellular retention is present within amino acid sequence 138–168 of TMC1 N-terminus. This novel signal may preclude the proper trafficking of TMC1 to the PM in heterologous cells.
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Affiliation(s)
- D C Soler
- The Department of Neurosurgery, University Hospitals Cleveland Medical Center, Cleveland, OH, USA. .,Brain Tumor and Neuro-Oncology Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA. .,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA.
| | - M Manikandan
- Department of Otolaryngology - HNS, Case Western Reserve University, Cleveland, OH, USA
| | - S R Gopal
- Department of Otolaryngology - HNS, Case Western Reserve University, Cleveland, OH, USA
| | - A E Sloan
- The Department of Neurosurgery, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.,Brain Tumor and Neuro-Oncology Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA
| | - T S McCormick
- Department of Dermatology, Case Western Reserve University, Cleveland, OH, USA.,Murdough Family Center for Psoriasis, Case Western Reserve University, Cleveland, OH, USA
| | - R Stepanyan
- Department of Otolaryngology - HNS, Case Western Reserve University, Cleveland, OH, USA. .,Department of Neurosciences, Case Western Reserve University, Cleveland, OH, USA.
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