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Dal Cortivo G, Dell’Orco D. Calcium- and Integrin-Binding Protein 2 (CIB2) in Physiology and Disease: Bright and Dark Sides. Int J Mol Sci 2022; 23:ijms23073552. [PMID: 35408910 PMCID: PMC8999013 DOI: 10.3390/ijms23073552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/19/2022] [Accepted: 03/22/2022] [Indexed: 12/04/2022] Open
Abstract
Calcium- and integrin-binding protein 2 (CIB2) is a small EF-hand protein capable of binding Mg2+ and Ca2+ ions. While its biological function remains largely unclear, an increasing number of studies have shown that CIB2 is an essential component of the mechano-transduction machinery that operates in cochlear hair cells. Mutations in the gene encoding CIB2 have been associated with non-syndromic deafness. In addition to playing an important role in the physiology of hearing, CIB2 has been implicated in a multitude of very different processes, ranging from integrin signaling in platelets and skeletal muscle to autophagy, suggesting extensive functional plasticity. In this review, we summarize the current understanding of biochemical and biophysical properties of CIB2 and the biological roles that have been proposed for the protein in a variety of processes. We also highlight the many molecular aspects that remain unclarified and deserve further investigation.
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52
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Sadeghi SG, Géléoc GSG. Editorial: Commonalities and Differences in Vestibular and Auditory Pathways. Front Neurosci 2022; 16:876798. [PMID: 35401079 PMCID: PMC8984178 DOI: 10.3389/fnins.2022.876798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 02/24/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Soroush G. Sadeghi
- Center for Hearing and Deafness, Department of Communicative Disorders and Science, University at Buffalo, Buffalo, NY, United States
- *Correspondence: Soroush G. Sadeghi
| | - Gwenaëlle S. G. Géléoc
- Boston Children's Hospital and Harvard Medical School, Boston, MA, United States
- Gwenaëlle S. G. Géléoc
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53
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Gianoli F, Hogan B, Dilly É, Risler T, Kozlov AS. Fast adaptation of cooperative channels engenders Hopf bifurcations in auditory hair cells. Biophys J 2022; 121:897-909. [PMID: 35176272 PMCID: PMC8943817 DOI: 10.1016/j.bpj.2022.02.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/22/2021] [Accepted: 02/09/2022] [Indexed: 12/01/2022] Open
Abstract
Since the pioneering work of Thomas Gold, published in 1948, it has been known that we owe our sensitive sense of hearing to a process in the inner ear that can amplify incident sounds on a cycle-by-cycle basis. Called the active process, it uses energy to counteract the viscous dissipation associated with sound-evoked vibrations of the ear's mechanotransduction apparatus. Despite its importance, the mechanism of the active process and the proximate source of energy that powers it have remained elusive, especially at the high frequencies characteristic of amniote hearing. This is partly due to our insufficient understanding of the mechanotransduction process in hair cells, the sensory receptors and amplifiers of the inner ear. It has been proposed previously that cyclical binding of Ca2+ ions to individual mechanotransduction channels could power the active process. That model, however, relied on tailored reaction rates that structurally forced the direction of the cycle. Here we ground our study on our previous model of hair-cell mechanotransduction, which relied on cooperative gating of pairs of channels, and incorporate into it the cyclical binding of Ca2+ ions. With a single binding site per channel and reaction rates drawn from thermodynamic principles, the current model shows that hair cells behave as nonlinear oscillators that exhibit Hopf bifurcations, dynamical instabilities long understood to be signatures of the active process. Using realistic parameter values, we find bifurcations at frequencies in the kilohertz range with physiological Ca2+ concentrations. The current model relies on the electrochemical gradient of Ca2+ as the only energy source for the active process and on the relative motion of cooperative channels within the stereociliary membrane as the sole mechanical driver. Equipped with these two mechanisms, a hair bundle proves capable of operating at frequencies in the kilohertz range, characteristic of amniote hearing.
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Affiliation(s)
| | - Brenna Hogan
- Department of Bioengineering, Imperial College London, London, UK
| | - Émilien Dilly
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, Paris, France
| | - Thomas Risler
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, Paris, France.
| | - Andrei S Kozlov
- Department of Bioengineering, Imperial College London, London, UK.
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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: 24] [Impact Index Per Article: 12.0] [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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55
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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: 18] [Impact Index Per Article: 9.0] [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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56
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Multiplexed Genome Editing for Efficient Phenotypic Screening in Zebrafish. Vet Sci 2022; 9:vetsci9020092. [PMID: 35202345 PMCID: PMC8879510 DOI: 10.3390/vetsci9020092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 12/30/2022] Open
Abstract
Zebrafish are widely used to investigate candidate genes for human diseases. While the emergence of CRISPR-Cas9 technology has revolutionized gene editing, the use of individual guide RNAs limits the efficiency and application of this technology in functional genetics research. Multiplexed genome editing significantly enhances the efficiency and scope of gene editing. Herein, we describe an efficient multiplexed genome editing strategy to generate zebrafish mutants. Following behavioural tests and histological examination, we identified one new candidate gene (tmem183a) for hearing loss. This study provides a robust genetic platform to quickly obtain zebrafish mutants and to identify candidate genes by phenotypic readouts.
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Li G, Li X, Zhuang S, Wang L, Zhu Y, Chen Y, Sun W, Wu Z, Zhou Z, Chen J, Huang X, Wang J, Li D, Li W, Wang H, Wei W. Gene editing and its applications in biomedicine. SCIENCE CHINA. LIFE SCIENCES 2022; 65:660-700. [PMID: 35235150 PMCID: PMC8889061 DOI: 10.1007/s11427-021-2057-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/06/2021] [Indexed: 02/06/2023]
Abstract
The steady progress in genome editing, especially genome editing based on the use of clustered regularly interspaced short palindromic repeats (CRISPR) and programmable nucleases to make precise modifications to genetic material, has provided enormous opportunities to advance biomedical research and promote human health. The application of these technologies in basic biomedical research has yielded significant advances in identifying and studying key molecular targets relevant to human diseases and their treatment. The clinical translation of genome editing techniques offers unprecedented biomedical engineering capabilities in the diagnosis, prevention, and treatment of disease or disability. Here, we provide a general summary of emerging biomedical applications of genome editing, including open challenges. We also summarize the tools of genome editing and the insights derived from their applications, hoping to accelerate new discoveries and therapies in biomedicine.
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Affiliation(s)
- Guanglei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Xiangyang Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Songkuan Zhuang
- Department of Clinical Laboratory, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, 518035, China
| | - Liren Wang
- Shanghai Frontiers Science Research Base of Genome Editing and Cell Therapy, Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Yifan Zhu
- Shanghai Frontiers Science Research Base of Genome Editing and Cell Therapy, Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Yangcan Chen
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wen Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zeguang Wu
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Zhuo Zhou
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Jia Chen
- Gene Editing Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Xingxu Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Jin Wang
- Department of Clinical Laboratory, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen, 518035, China.
| | - Dali Li
- Shanghai Frontiers Science Research Base of Genome Editing and Cell Therapy, Shanghai Key Laboratory of Regulatory Biology, School of Life Sciences, East China Normal University, Shanghai, 200241, China.
| | - Wei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China.
- Bejing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
- HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China.
| | - Haoyi Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Institute for Stem Cell and Regenerative Medicine, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Wensheng Wei
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, 100871, China.
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Jeong H, Clark S, Goehring A, Dehghani-Ghahnaviyeh S, Rasouli A, Tajkhorshid E, Gouaux E. Structures of the TMC-1 complex illuminate mechanosensory transduction. Nature 2022; 610:796-803. [PMID: 36224384 PMCID: PMC9605866 DOI: 10.1038/s41586-022-05314-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/02/2022] [Indexed: 02/05/2023]
Abstract
The initial step in the sensory transduction pathway underpinning hearing and balance in mammals involves the conversion of force into the gating of a mechanosensory transduction channel1. Despite the profound socioeconomic impacts of hearing disorders and the fundamental biological significance of understanding mechanosensory transduction, the composition, structure and mechanism of the mechanosensory transduction complex have remained poorly characterized. Here we report the single-particle cryo-electron microscopy structure of the native transmembrane channel-like protein 1 (TMC-1) mechanosensory transduction complex isolated from Caenorhabditis elegans. The two-fold symmetric complex is composed of two copies each of the pore-forming TMC-1 subunit, the calcium-binding protein CALM-1 and the transmembrane inner ear protein TMIE. CALM-1 makes extensive contacts with the cytoplasmic face of the TMC-1 subunits, whereas the single-pass TMIE subunits reside on the periphery of the complex, poised like the handles of an accordion. A subset of complexes additionally includes a single arrestin-like protein, arrestin domain protein (ARRD-6), bound to a CALM-1 subunit. Single-particle reconstructions and molecular dynamics simulations show how the mechanosensory transduction complex deforms the membrane bilayer and suggest crucial roles for lipid-protein interactions in the mechanism by which mechanical force is transduced to ion channel gating.
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Affiliation(s)
- Hanbin Jeong
- grid.433851.80000 0004 0608 3919Vollum Institute, Oregon Health and Science University, Portland, OR USA
| | - Sarah Clark
- grid.433851.80000 0004 0608 3919Vollum Institute, Oregon Health and Science University, Portland, OR USA
| | - April Goehring
- grid.433851.80000 0004 0608 3919Vollum Institute, Oregon Health and Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Howard Hughes Medical Institute, Oregon Health and Science University, Portland, OR USA
| | - Sepehr Dehghani-Ghahnaviyeh
- grid.35403.310000 0004 1936 9991Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Ali Rasouli
- grid.35403.310000 0004 1936 9991Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Emad Tajkhorshid
- grid.35403.310000 0004 1936 9991Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL USA ,grid.35403.310000 0004 1936 9991Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Eric Gouaux
- grid.433851.80000 0004 0608 3919Vollum Institute, Oregon Health and Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Howard Hughes Medical Institute, Oregon Health and Science University, Portland, OR USA
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59
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Miller KK, Atkinson P, Mendoza KR, Ó Maoiléidigh D, Grillet N. Dimensions of a Living Cochlear Hair Bundle. Front Cell Dev Biol 2021; 9:742529. [PMID: 34900993 PMCID: PMC8657763 DOI: 10.3389/fcell.2021.742529] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/13/2021] [Indexed: 11/23/2022] Open
Abstract
The hair bundle is the mechanosensory organelle of hair cells that detects mechanical stimuli caused by sounds, head motions, and fluid flows. Each hair bundle is an assembly of cellular-protrusions called stereocilia, which differ in height to form a staircase. Stereocilia have different heights, widths, and separations in different species, sensory organs, positions within an organ, hair-cell types, and even within a single hair bundle. The dimensions of the stereociliary assembly dictate how the hair bundle responds to stimuli. These hair-bundle properties have been measured previously only to a limited degree. In particular, mammalian data are either incomplete, lack control for age or position within an organ, or have artifacts owing to fixation or dehydration. Here, we provide a complete set of measurements for postnatal day (P) 11 C57BL/6J mouse apical inner hair cells (IHCs) obtained from living tissue, tissue mildly-fixed for fluorescent imaging, or tissue strongly fixed and dehydrated for scanning electronic microscopy (SEM). We found that hair bundles mildly-fixed for fluorescence had the same dimensions as living hair bundles, whereas SEM-prepared hair bundles shrank uniformly in stereociliary heights, widths, and separations. By determining the shrinkage factors, we imputed live dimensions from SEM that were too small to observe optically. Accordingly, we created the first complete blueprint of a living IHC hair bundle. We show that SEM-prepared measurements strongly affect calculations of a bundle’s mechanical properties – overestimating stereociliary deflection stiffness and underestimating the fluid coupling between stereocilia. The methods of measurement, the data, and the consequences we describe illustrate the high levels of accuracy and precision required to understand hair-bundle mechanotransduction.
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Affiliation(s)
- Katharine K Miller
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, CA, United States
| | - Patrick Atkinson
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, CA, United States
| | - Kyssia Ruth Mendoza
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, CA, United States
| | - Dáibhid Ó Maoiléidigh
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, CA, United States
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, CA, United States
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60
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Holt JR, Tobin M, Elferich J, Gouaux E, Ballesteros A, Yan Z, Ahmed ZM, Nicolson T. Putting the Pieces Together: the Hair Cell Transduction Complex. J Assoc Res Otolaryngol 2021; 22:601-608. [PMID: 34617206 PMCID: PMC8599550 DOI: 10.1007/s10162-021-00808-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/16/2021] [Indexed: 11/30/2022] Open
Abstract
Identification of the components of the mechanosensory transduction complex in hair cells has been a major research interest for many auditory and vestibular scientists and has attracted attention from outside the field. The past two decades have witnessed a number of significant advances with emergence of compelling evidence implicating at least a dozen distinct molecular components of the transduction machinery. Yet, how the pieces of this ensemble fit together and function in harmony to enable the senses of hearing and balance has not been clarified. The goal of this review is to summarize a 2021 symposium presented at the annual mid-winter meeting of the Association for Research in Otolaryngology. The symposium brought together the latest insights from within and beyond the field to examine individual components of the transduction complex and how these elements interact at molecular, structural, and biophysical levels to gate mechanosensitive channels and initiate sensory transduction in the inner ear. The review includes a brief historical background to set the stage for topics to follow that focus on structure, properties, and interactions of proteins such as CDH23, PCDH15, LHFPL5, TMIE, TMC1/2, and CIB2/3. We aim to present the diversity of ideas in this field and highlight emerging theories and concepts. This review will not only provide readers with a deeper appreciation of the components of the transduction apparatus and how they function together, but also bring to light areas of broad agreement, areas of scientific controversy, and opportunities for future scientific discovery.
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Affiliation(s)
- Jeffrey R Holt
- Departments of Otolaryngology & Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
| | - Mélanie Tobin
- Laboratoire Physico-Chimie Curie, Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Paris, 75005, France
- Departments of Otorhinolaryngology, Neuroscience and Neurology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Johannes Elferich
- Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Angela Ballesteros
- Molecular Physiology and Biophysics Section, Disorders and Stroke, National Institute of Neurological, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zhiqiang Yan
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Zubair M Ahmed
- Department of Otolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA
| | - Teresa Nicolson
- Department of Otolaryngology-Head & Neck Surgery, Stanford University, Stanford, CA, USA
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61
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Iliff AJ, Wang C, Ronan EA, Hake AE, Guo Y, Li X, Zhang X, Zheng M, Liu J, Grosh K, Duncan RK, Xu XZS. The nematode C. elegans senses airborne sound. Neuron 2021; 109:3633-3646.e7. [PMID: 34555314 PMCID: PMC8602785 DOI: 10.1016/j.neuron.2021.08.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/21/2021] [Accepted: 08/27/2021] [Indexed: 11/26/2022]
Abstract
Unlike olfaction, taste, touch, vision, and proprioception, which are
widespread across animal phyla, hearing is found only in vertebrates and some
arthropods. The vast majority of invertebrate species are thus considered
insensitive to sound. Here, we challenge this conventional view by showing that
the earless nematode C. elegans senses airborne sound at
frequencies reaching the kHz range. Sound vibrates C. elegans
skin, which acts as a pressure-to-displacement transducer similar to vertebrate
eardrum, activates sound-sensitive FLP/PVD neurons attached to the skin, and
evokes phonotaxis behavior. We identified two nAChRs that transduce sound
signals independently of ACh, revealing an unexpected function of nAChRs in
mechanosensation. Thus, the ability to sense airborne sound is not restricted to
vertebrates and arthropods as previously thought, and might have evolved
multiple times independently in the animal kingdom, suggesting convergent
evolution. Our studies also demonstrate that animals without ears may not be
presumed to be sound insensitive. Hearing is thought to exist only in vertebrates and some arthropods, but
not other animal phyla. Here, Xu and colleagues report that the earless nematode
C. elegans senses airborne sound and engages in phonotaxis.
Thus, hearing might have evolved multiple times independently in the animal
kingdom, suggesting convergent evolution.
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Affiliation(s)
- Adam J Iliff
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Can Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Elizabeth A Ronan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alison E Hake
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuling Guo
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xia Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinxing Zhang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Maohua Zheng
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianfeng Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Karl Grosh
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - R Keith Duncan
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - X Z Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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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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63
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Parpaite T, Brosse L, Séjourné N, Laur A, Mechioukhi Y, Delmas P, Coste B. Patch-seq of mouse DRG neurons reveals candidate genes for specific mechanosensory functions. Cell Rep 2021; 37:109914. [PMID: 34731626 PMCID: PMC8578708 DOI: 10.1016/j.celrep.2021.109914] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/16/2021] [Accepted: 10/09/2021] [Indexed: 12/13/2022] Open
Abstract
A variety of mechanosensory neurons are involved in touch, proprioception, and pain. Many molecular components of the mechanotransduction machinery subserving these sensory modalities remain to be discovered. Here, we combine recordings of mechanosensitive (MS) currents in mechanosensory neurons with single-cell RNA sequencing. Transcriptional profiles are mapped onto previously identified sensory neuron types to identify cell-type correlates between datasets. Correlation of current signatures with single-cell transcriptomes provides a one-to-one correspondence between mechanoelectric properties and transcriptomically defined neuronal populations. Moreover, a gene-expression differential comparison provides a set of candidate genes for mechanotransduction complexes. Piezo2 is expectedly found to be enriched in rapidly adapting MS current-expressing neurons, whereas Tmem120a and Tmem150c, thought to mediate slow-type MS currents, are uniformly expressed in all mechanosensory neuron subtypes. Further knockdown experiments disqualify them as mediating MS currents in sensory neurons. This dataset constitutes an open resource to explore further the cell-type-specific determinants of mechanosensory properties.
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Affiliation(s)
- Thibaud Parpaite
- Aix Marseille Université, CNRS, LNC-UMR 7291, 13344 Marseille, France
| | - Lucie Brosse
- Aix Marseille Université, CNRS, LNC-UMR 7291, 13344 Marseille, France
| | - Nina Séjourné
- Aix Marseille Université, CNRS, LNC-UMR 7291, 13344 Marseille, France
| | - Amandine Laur
- Aix Marseille Université, CNRS, LNC-UMR 7291, 13344 Marseille, France
| | | | - Patrick Delmas
- Aix Marseille Université, CNRS, LNC-UMR 7291, 13344 Marseille, France
| | - Bertrand Coste
- Aix Marseille Université, CNRS, LNC-UMR 7291, 13344 Marseille, France.
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64
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Beurg M, Nam JH, Fettiplace R. The speed of the hair cell mechanotransducer channel revealed by fluctuation analysis. J Gen Physiol 2021; 153:212584. [PMID: 34411238 PMCID: PMC8383808 DOI: 10.1085/jgp.202112959] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/01/2021] [Indexed: 11/22/2022] Open
Abstract
Although mechanoelectrical transducer (MET) channels have been extensively studied, uncertainty persists about their molecular architecture and single-channel conductance. We made electrical measurements from mouse cochlear outer hair cells (OHCs) to reexamine the MET channel conductance comparing two different methods. Analysis of fluctuations in the macroscopic currents showed that the channel conductance in apical OHCs determined from nonstationary noise analysis was about half that of single-channel events recorded after tip link destruction. We hypothesized that this difference reflects a bandwidth limitation in the noise analysis, which we tested by simulations of stochastic fluctuations in modeled channels. Modeling indicated that the unitary conductance depended on the relative values of the channel activation time constant and the applied low-pass filter frequency. The modeling enabled the activation time constant of the channel to be estimated for the first time, yielding a value of only a few microseconds. We found that the channel conductance, assayed with both noise and recording of single-channel events, was reduced by a third in a new deafness mutant, Tmc1 p.D528N. Our results indicate that noise analysis is likely to underestimate MET channel amplitude, which is better characterized from recordings of single-channel events.
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Affiliation(s)
- Maryline Beurg
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Jong-Hoon Nam
- Departments of Mechanical Engineering and Biomechanical Engineering, University of Rochester, Rochester, NY
| | - Robert Fettiplace
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI
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65
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Abstract
PURPOSE OF REVIEW We review recent progress in the characterization of spiral ganglion neurons (SGNs), the afferent neurons that transmit sound information from mechanosensory hair cells in the inner ear to the central nervous system. RECENT FINDINGS Single-cell ribonucleic acid sequencing studies of murine SGNs have demonstrated that SGNs consist of molecularly distinct subtypes. The molecularly defined SGN subtypes likely correspond to SGN subtypes previously identified on the basis of physiological properties, although this has not been experimentally demonstrated. Subtype maturation is completed postnatally in an activity-dependent manner and is impaired in several models of hearing loss. SUMMARY The recent molecular studies open new avenues to rigorously test whether SGN subtypes are important for the encoding of different sound features and if they show differential vulnerability to genetic factors and environmental insults. This could have important implications for the development of therapeutic strategies to treat hearing loss.
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Affiliation(s)
- Shuohao Sun
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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66
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Sun S, Li S, Luo Z, Ren M, He S, Wang G, Liu Z. Dual expression of Atoh1 and Ikzf2 promotes transformation of adult cochlear supporting cells into outer hair cells. eLife 2021; 10:66547. [PMID: 34477109 PMCID: PMC8439656 DOI: 10.7554/elife.66547] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 09/02/2021] [Indexed: 12/24/2022] Open
Abstract
Mammalian cochlear outer hair cells (OHCs) are essential for hearing. Severe hearing impairment follows OHC degeneration. Previous attempts at regenerating new OHCs from cochlear supporting cells (SCs) have been unsuccessful, notably lacking expression of the key OHC motor protein, Prestin. Thus, regeneration of Prestin+ OHCs represents a barrier to restore auditory function in vivo. Here, we reported the successful in vivo conversion of adult mouse cochlear SCs into Prestin+ OHC-like cells through the concurrent induction of two key transcriptional factors known to be necessary for OHC development: Atoh1 and Ikzf2. Single-cell RNA sequencing revealed the upregulation of 729 OHC genes and downregulation of 331 SC genes in OHC-like cells. The resulting differentiation status of these OHC-like cells was much more advanced than previously achieved. This study thus established an efficient approach to induce the regeneration of Prestin+ OHCs, paving the way for in vivo cochlear repair via SC transdifferentiation.
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Affiliation(s)
- Suhong Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shuting Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhengnan Luo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, 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, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shunji He
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 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, China.,University of Chinese Academy of Sciences, Beijing, 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, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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67
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Roy Choudhury A, Großhans J, Kong D. Ion Channels in Epithelial Dynamics and Morphogenesis. Cells 2021; 10:cells10092280. [PMID: 34571929 PMCID: PMC8465836 DOI: 10.3390/cells10092280] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/22/2021] [Accepted: 08/30/2021] [Indexed: 01/21/2023] Open
Abstract
Mechanosensitive ion channels mediate the neuronal sensation of mechanical signals such as sound, touch, and pain. Recent studies point to a function of these channel proteins in cell types and tissues in addition to the nervous system, such as epithelia, where they have been little studied, and their role has remained elusive. Dynamic epithelia are intrinsically exposed to mechanical forces. A response to pull and push is assumed to constitute an essential part of morphogenetic movements of epithelial tissues, for example. Mechano-gated channels may participate in sensing and responding to such forces. In this review, focusing on Drosophila, we highlight recent results that will guide further investigations concerned with the mechanistic role of these ion channels in epithelial cells.
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68
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Kasahara Y, Narukawa M, Ishimaru Y, Kanda S, Umatani C, Takayama Y, Tominaga M, Oka Y, Kondo K, Kondo T, Takeuchi A, Misaka T, Abe K, Asakura T. TMC4 is a novel chloride channel involved in high-concentration salt taste sensation. J Physiol Sci 2021; 71:23. [PMID: 34429071 PMCID: PMC10717410 DOI: 10.1186/s12576-021-00807-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/16/2021] [Indexed: 12/27/2022]
Abstract
"Salty taste" sensation is evoked when sodium and chloride ions are present together in the oral cavity. The presence of an epithelial cation channel that receives Na+ has previously been reported. However, no molecular entity involving Cl- receptors has been elucidated. We report the strong expression of transmembrane channel-like 4 (TMC4) in the circumvallate and foliate papillae projected to the glossopharyngeal nerve, mediating a high-concentration of NaCl. Electrophysiological analysis using HEK293T cells revealed that TMC4 was a voltage-dependent Cl- channel and the consequent currents were completely inhibited by NPPB, an anion channel blocker. TMC4 allowed permeation of organic anions including gluconate, but their current amplitudes at positive potentials were less than that of Cl-. Tmc4-deficient mice showed significantly weaker glossopharyngeal nerve response to high-concentration of NaCl than the wild-type littermates. These results indicated that TMC4 is a novel chloride channel that responds to high-concentration of NaCl.
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Affiliation(s)
- Yoichi Kasahara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Masataka Narukawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Department of Food and Nutrition, Kyoto Women's University, 35 Kitahiyoshicho Imakumano Higashiyama, Kyoto, 605-8501, Japan
| | - Yoshiro Ishimaru
- Department of Agricultural Chemistry, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Shinji Kanda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Chie Umatani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yasunori Takayama
- Division of Cell Signaling, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Aza-Higashiyama, Myodaijicho, Okazaki, Aichi, 444-8787, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Aza-Higashiyama, Myodaijicho, Okazaki, Aichi, 444-8787, Japan
- Thermal Biology Research Group, Exploratory Research Center On Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Aza-Higashiyama, Myodaijicho, Okazaki, Aichi, 444-8787, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kaori Kondo
- Laboratory for Developmental Genetics, RIKEN-IMS, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Takashi Kondo
- Laboratory for Developmental Genetics, RIKEN-IMS, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Ayako Takeuchi
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, and Life Science Innovation Center, University of Fukui, Fukui, 910-1193, Japan
| | - Takumi Misaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Keiko Abe
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Kanagawa Institute of Industrial Science and Technology (KISTEC), LiSE 4F C-4, 3-25-13 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Tomiko Asakura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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69
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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: 10] [Impact Index Per Article: 3.3] [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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70
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Zhao Q, Shen Y, Li X, Tian F, Yu X, Yobas L, Park H, Duan Y, Huang P. Analyzing protein-protein interactions in rare cells using microbead-based single-molecule pulldown assay. LAB ON A CHIP 2021; 21:3137-3149. [PMID: 34165117 DOI: 10.1039/d1lc00260k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
For studying protein-protein interactions (PPIs) in general, a powerful and commonly used technique is conventional coimmunoprecipitation (co-IP/pulldown) followed by western blotting. However, the technique does not provide precise information regarding the kinetics and stoichiometry of PPIs. Another drawback is that the sensitivity of conventional co-IP is not suitable for examining PPIs in rare cells such as sensory hair cells, circulating tumor cells, embryonic stem cells, and subsets of immune cells. The current single-molecule pulldown (SiMPull) assay can potentially be used for studying PPIs in rare cells but its wide application is hindered by the high technical barrier and time consumption. We report an innovative, agarose microbead-based approach for SiMPull. We used commercially available, pre-surface-functionalized agarose microbeads to capture the protein of interest together with its binding partners specifically from cell extracts and observed these interactions under a microscope at the single-molecule level. Relative to the original method, microbead-based SiMPull is considerably faster, easier to use, and more reproducible and yet provides similar sensitivity and signal-to-background ratio; specifically, with the new method, sample-preparation time is substantially decreased (from ∼10 to ∼3 h). These crucial features should facilitate wide application of the powerful and versatile SiMPull method in common biological and clinical laboratories. Notably, by exploiting the simplicity and ultrahigh sensitivity of microbead-based SiMPull, we used the method in the study of rare auditory hair cells and γδ T cells for the first time.
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Affiliation(s)
- Qirui Zhao
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
| | - Yusheng Shen
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiaofen Li
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Fang Tian
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiaojie Yu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
| | - Levent Yobas
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China and Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Hyokeun Park
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China. and Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yuanyuan Duan
- Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Pingbo Huang
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China. and Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China and HKUST Shenzhen Research Institute, Hong Kong University of Science and Technology, Hong Kong, China and Hong Kong Branch of Guangdong Southern Marine Science and Engineering Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong, China
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71
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Niu Y, Tao X, Vaisey G, Olinares PDB, Alwaseem H, Chait BT, MacKinnon R. Analysis of the mechanosensor channel functionality of TACAN. eLife 2021; 10:71188. [PMID: 34374644 PMCID: PMC8376246 DOI: 10.7554/elife.71188] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/06/2021] [Indexed: 02/06/2023] Open
Abstract
Mechanosensitive ion channels mediate transmembrane ion currents activated by mechanical forces. A mechanosensitive ion channel called TACAN was recently reported. We began to study TACAN with the intent to understand how it senses mechanical forces and functions as an ion channel. Using cellular patch-recording methods, we failed to identify mechanosensitive ion channel activity. Using membrane reconstitution methods, we found that TACAN, at high protein concentrations, produces heterogeneous conduction levels that are not mechanosensitive and are most consistent with disruptions of the lipid bilayer. We determined the structure of TACAN using single-particle cryo-electron microscopy and observed that it is a symmetrical dimeric transmembrane protein. Each protomer contains an intracellular-facing cleft with a coenzyme A cofactor, confirmed by mass spectrometry. The TACAN protomer is related in three-dimensional structure to a fatty acid elongase, ELOVL7. Whilst its physiological function remains unclear, we anticipate that TACAN is not a mechanosensitive ion channel.
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Affiliation(s)
- Yiming Niu
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States
| | - Xiao Tao
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States.,Howard Hughes Medical Institute, New York, United States
| | - George Vaisey
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States.,Howard Hughes Medical Institute, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, United States
| | - Hanan Alwaseem
- Proteomics Resource Center, Rockefeller University, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, United States
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, Rockefeller University, New York, United States.,Howard Hughes Medical Institute, New York, United States
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72
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Genetic etiology of hereditary hearing loss in the Gulf Cooperation Council countries. Hum Genet 2021; 141:595-605. [PMID: 34338889 DOI: 10.1007/s00439-021-02323-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
The past 30 years have seen an exponential growth concerning the identification of genes and variants responsible for hereditary hearing loss (HL) worldwide. This has led to a huge gain in our understanding of molecular mechanisms of hearing and deafness, which improved diagnosis for populations with hereditary HL. Many communities around the world, especially in the Middle East and North Africa, have a high prevalence of consanguineous marriages. Congenital monogenic conditions, such as recessive HL, are more common in these populations due to high consanguinity rates. Many studies have shown that high rates of consanguinity, endogamy, and first cousin marriages were observed in the six countries of the Gulf Cooperation Council (GCC). The intent of this study is to investigate the etiology of HL in the GCC region. A deep literature review of genes and variants responsible for HL in this region revealed 89 recessive DNA pathogenic variants reported in 138 cases/familial cases. A total of 21 genes responsible for non-syndromic hearing loss (NSHL) and 17 genes associated with syndromic hearing loss (SHL) were reported in cases from the GCC region. Out of 156 reported affected cases, 112 showed HL only, and 44 showed HL associated with other clinical manifestations. This data suggests that in the GCC region 72% of HL forms are non-syndromic and 28% are syndromic. For individuals with NSHL, 66% of variants were detected in four genes (GJB2, OTOF, TMC1 and CDH23), with a predominance of variants located in the GJB2 gene (37.5%). However, among SHL, Usher syndrome was the more frequent as it has been observed in 41% of the reported syndromic GCC cases. Finally, our analysis showed that HL genetics testing and research in the GCC region took advantage of the next generation sequencing (NGS)-based techniques, as approximately 58% of reported variants were identified using this technology.
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73
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An Integrated Perspective of Evolution and Development: From Genes to Function to Ear, Lateral Line and Electroreception. DIVERSITY 2021; 13. [PMID: 35505776 PMCID: PMC9060560 DOI: 10.3390/d13080364] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Four sensory systems (vestibular, lateral line, electroreception, auditory) are unique and project exclusively to the brainstem of vertebrates. All sensory neurons depend on a common set of genes (Eya1, Sox2, Neurog1, Neurod1) that project to a dorsal nucleus and an intermediate nucleus, which differentiate into the vestibular ear, lateral line and electroreception in vertebrates. In tetrapods, a loss of two sensory systems (lateral line, electroreception) leads to the development of a unique ear and auditory system in amniotes. Lmx1a/b, Gdf7, Wnt1/3a, BMP4/7 and Atoh1 define the lateral line, electroreception and auditory nuclei. In contrast, vestibular nuclei depend on Neurog1/2, Ascl1, Ptf1a and Olig3, among others, to develop an independent origin of the vestibular nuclei. A common origin of hair cells depends on Eya1, Sox2 and Atoh1, which generate the mechanosensory cells. Several proteins define the polarity of hair cells in the ear and lateral line. A unique connection of stereocilia requires CDH23 and PCDH15 for connections and TMC1/2 proteins to perceive mechanosensory input. Electroreception has no polarity, and a different system is used to drive electroreceptors. All hair cells function by excitation via ribbons to activate neurons that innervate the distinct target areas. An integrated perspective is presented to understand the gain and loss of different sensory systems.
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74
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Warren B, Nowotny M. Bridging the Gap Between Mammal and Insect Ears – A Comparative and Evolutionary View of Sound-Reception. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.667218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Insects must wonder why mammals have ears only in their head and why they evolved only one common principle of ear design—the cochlea. Ears independently evolved at least 19 times in different insect groups and therefore can be found in completely different body parts. The morphologies and functional characteristics of insect ears are as wildly diverse as the ecological niches they exploit. In both, insects and mammals, hearing organs are constrained by the same biophysical principles and their respective molecular processes for mechanotransduction are thought to share a common evolutionary origin. Due to this, comparative knowledge of hearing across animal phyla provides crucial insight into fundamental processes of auditory transduction, especially at the biomechanical and molecular level. This review will start by comparing hearing between insects and mammals in an evolutionary context. It will then discuss current findings about sound reception will help to bridge the gap between both research fields.
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Liang X, Qiu X, Dionne G, Cunningham CL, Pucak ML, Peng G, Kim YH, Lauer A, Shapiro L, Müller U. CIB2 and CIB3 are auxiliary subunits of the mechanotransduction channel of hair cells. Neuron 2021; 109:2131-2149.e15. [PMID: 34089643 PMCID: PMC8374959 DOI: 10.1016/j.neuron.2021.05.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 01/17/2021] [Accepted: 05/07/2021] [Indexed: 12/25/2022]
Abstract
CIB2 is a Ca2+- and Mg2+-binding protein essential for mechanoelectrical transduction (MET) by cochlear hair cells, but not by vestibular hair cells that co-express CIB2 and CIB3. Here, we show that in cochlear hair cells, CIB3 can functionally substitute for CIB2. Using X-ray crystallography, we demonstrate that CIB2 and CIB3 are structurally similar to KChIP proteins, auxiliary subunits of voltage-gated Kv4 channels. CIB2 and CIB3 bind to TMC1/2 through a domain in TMC1/2 flanked by transmembrane domains 2 and 3. The co-crystal structure of the CIB-binding domain in TMC1 with CIB3 reveals that interactions are mediated through a conserved CIB hydrophobic groove, similar to KChIP1 binding of Kv4. Functional studies in mice show that CIB2 regulates TMC1/2 localization and function in hair cells, processes that are affected by deafness-causing CIB2 mutations. We conclude that CIB2 and CIB3 are MET channel auxiliary subunits with striking similarity to Kv4 channel auxiliary subunits.
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Affiliation(s)
- Xiaoping Liang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gilman Dionne
- Department of Biochemistry and Molecular Biophysics, Zuckerman Mind Brain, Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Christopher L Cunningham
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michele L Pucak
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guihong Peng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ye-Hyun Kim
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amanda Lauer
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Zuckerman Mind Brain, Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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76
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Du H, Ye C, Wu D, Zang YY, Zhang L, Chen C, He XY, Yang JJ, Hu P, Xu Z, Wan G, Shi YS. The Cation Channel TMEM63B Is an Osmosensor Required for Hearing. Cell Rep 2021; 31:107596. [PMID: 32375046 DOI: 10.1016/j.celrep.2020.107596] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/21/2020] [Accepted: 04/10/2020] [Indexed: 01/08/2023] Open
Abstract
Hypotonic stress causes the activation of swelling-activated nonselective cation channels (NSCCs), which leads to Ca2+-dependent regulatory volume decrease (RVD) and adaptive maintenance of the cell volume; however, the molecular identities of the osmosensitive NSCCs remain unclear. Here, we identified TMEM63B as an osmosensitive NSCC activated by hypotonic stress. TMEM63B is enriched in the inner ear sensory hair cells. Genetic deletion of TMEM63B results in necroptosis of outer hair cells (OHCs) and progressive hearing loss. Mechanistically, the TMEM63B channel mediates hypo-osmolarity-induced Ca2+ influx, which activates Ca2+-dependent K+ channels required for the maintenance of OHC morphology. These findings demonstrate that TMEM63B is an osmosensor of the mammalian inner ear and the long-sought cation channel mediating Ca2+-dependent RVD.
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Affiliation(s)
- Han Du
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210032, China; Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Chang Ye
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210032, China; Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Dan Wu
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210032, China; Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Yan-Yu Zang
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210032, China; Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Linqing Zhang
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Chen Chen
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Xue-Yan He
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China
| | - Jian-Jun Yang
- Department of Anesthesiology and Perioperative Medicine, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province 450052, China
| | - Ping Hu
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Healthcare Hospital, Nanjing 210004, China
| | - Zhengfeng Xu
- Department of Prenatal Diagnosis, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Healthcare Hospital, Nanjing 210004, China
| | - Guoqiang Wan
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China; Institute for Brain Sciences, Nanjing University, Nanjing 210032, China.
| | - Yun Stone Shi
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210032, China; Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210032, China; Institute for Brain Sciences, Nanjing University, Nanjing 210032, China; Chemistry and Biomedicine Innovation Center, Nanjing University, Nanjing 210032, China.
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77
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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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78
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Farhadi M, Razmara E, Balali M, Hajabbas Farshchi Y, Falah M. How Transmembrane Inner Ear (TMIE) plays role in the auditory system: A mystery to us. J Cell Mol Med 2021; 25:5869-5883. [PMID: 33987950 PMCID: PMC8256367 DOI: 10.1111/jcmm.16610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/26/2021] [Indexed: 01/19/2023] Open
Abstract
Different cellular mechanisms contribute to the hearing sense, so it is obvious that any disruption in such processes leads to hearing impairment that greatly influences the global economy and quality of life of the patients and their relatives. In the past two decades, transmembrane inner ear (TMIE) protein has received a great deal of research interest because its impairments cause hereditary deafness in humans. This evolutionarily conserved membrane protein contributes to a fundamental complex that plays role in the maintenance and function of the sensory hair cells. Although the critical roles of the TMIE in mechanoelectrical transduction or hearing procedures have been discussed, there are little to no review papers summarizing the roles of the TMIE in the auditory system. In order to fill this gap, herein, we discuss the important roles of this protein in the auditory system including its role in mechanotransduction, olivocochlear synapse, morphology and different signalling pathways; we also review the genotype-phenotype correlation that can per se show the possible roles of this protein in the auditory system.
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Affiliation(s)
- Mohammad Farhadi
- ENT and Head and Neck Research Center and DepartmentThe Five Senses Health InstituteHazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
| | - Ehsan Razmara
- Australian Regenerative Medicine InstituteMonash UniversityClaytonVICAustralia
| | - Maryam Balali
- ENT and Head and Neck Research Center and DepartmentThe Five Senses Health InstituteHazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
| | - Yeganeh Hajabbas Farshchi
- Department of Cellular and Molecular BiologyTehran Medical SciencesIslamic Azad UniversityTehranIran
| | - Masoumeh Falah
- ENT and Head and Neck Research Center and DepartmentThe Five Senses Health InstituteHazrat Rasoul Akram HospitalIran University of Medical SciencesTehranIran
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79
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Hakizimana P, Fridberger A. Inner hair cell stereocilia are embedded in the tectorial membrane. Nat Commun 2021; 12:2604. [PMID: 33972539 PMCID: PMC8110531 DOI: 10.1038/s41467-021-22870-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 04/06/2021] [Indexed: 02/03/2023] Open
Abstract
Mammalian hearing depends on sound-evoked displacements of the stereocilia of inner hair cells (IHCs), which cause the endogenous mechanoelectrical transducer channels to conduct inward currents of cations including Ca2+. Due to their presumed lack of contacts with the overlaying tectorial membrane (TM), the putative stimulation mechanism for these stereocilia is by means of the viscous drag of the surrounding endolymph. However, despite numerous efforts to characterize the TM by electron microscopy and other techniques, the exact IHC stereocilia-TM relationship remains elusive. Here we show that Ca2+-rich filamentous structures, that we call Ca2+ ducts, connect the TM to the IHC stereocilia to enable mechanical stimulation by the TM while also ensuring the stereocilia access to TM Ca2+. Our results call for a reassessment of the stimulation mechanism for the IHC stereocilia and the TM role in hearing.
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Affiliation(s)
- Pierre Hakizimana
- grid.5640.70000 0001 2162 9922Department of Biomedical and Clinical Sciences (BKV), Linköping University, Linköping, Sweden
| | - Anders Fridberger
- grid.5640.70000 0001 2162 9922Department of Biomedical and Clinical Sciences (BKV), Linköping University, Linköping, Sweden
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80
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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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81
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French AS, Warren B. Gene transcription changes in a locust model of noise-induced deafness. J Neurophysiol 2021; 125:2264-2278. [PMID: 33949886 PMCID: PMC8285658 DOI: 10.1152/jn.00119.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Locusts have auditory structures called Müller’s organs attached to tympanic membranes on either side of the abdomen. We measured the normalized abundances of 500 different mRNA transcripts in 320 Müller’s organs obtained from 160 locusts (Schistocerca gregaria) that had been subjected to a loud continuous 3-kHz tone for 24 h. Abundance ratios were then measured relative to transcripts from 360 control organs. A histogram of the number of observed transcripts versus their abundance ratios (noise exposed/control) was well fitted by a Cauchy distribution with median value near one. Transcripts below 5% and above 95% of the cumulative distribution function of the fitted Cauchy distribution were selected as putatively different from the expected values of an untreated preparation. This yielded eight transcripts with ratios increased by noise exposure (ratios 1.689–3.038) and 18 transcripts with reduced ratios (0.069–0.457). Most of the transcripts with increased abundance represented genes responsible for cuticular construction, suggesting extensive remodeling of some or all the cuticular components of the auditory structure, whereas the reduced abundance transcripts were mostly involved in lipid and protein storage and metabolism, suggesting a profound reduction in metabolic activity in response to the overstimulation. NEW & NOTEWORTHY Locust ears have functional and genetic similarities to human ears, including loss of hearing from age or noise exposure. We measured transcript abundances in transcriptomes of noise-exposed and control locust ears. The data indicate remodeling of the ear tympanum and profound reductions in metabolism that may explain reduced sound transduction. These findings advance our understanding of this useful model and suggest further experiments to elucidate mechanisms that ears use to cope with excessive stimulation.
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Affiliation(s)
- Andrew S French
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ben Warren
- Department of Neuroscience, Psychology and Behavior, University of Leicester, Leicester, United Kingdom
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82
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Ballesteros A, Fitzgerald TS, Swartz KJ. Expression of a membrane-targeted fluorescent reporter disrupts auditory hair cell mechanoelectrical transduction and causes profound deafness. Hear Res 2021; 404:108212. [PMID: 33667877 PMCID: PMC8035305 DOI: 10.1016/j.heares.2021.108212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 11/22/2022]
Abstract
The reporter mT/mG mice expressing a membrane-targeted fluorescent protein are becoming widely used to study the auditory and vestibular system due to its versatility. Here we show that high expression levels of the fluorescent mtdTomato reporter affect the function of the sensory hair cells and the auditory performance of mT/mG transgenic mice. Auditory brainstem responses and distortion product otoacoustic emissions revealed that adult mT/mG homozygous mice are profoundly deaf, whereas heterozygous mice present high frequency loss. We explore whether this line would be useful for studying and visualizing the membrane of auditory hair cells by airyscan super-resolution confocal microscopy. Membrane localization of the reporter was observed in hair cells of the cochlea, facilitating imaging of both cell bodies and stereocilia bundles without altering cellular architecture or the expression of the integral membrane motor protein prestin. Remarkably, hair cells from mT/mG homozygous mice failed to uptake the FM1-43 dye and to locate TMC1 at the stereocilia, indicating defective mechanotransduction machinery. Our work emphasizes that precautions must be considered when working with reporter mice and highlights the potential role of the cellular membrane in maintaining functional hair cells and ensuring proper hearing.
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Affiliation(s)
- Angela Ballesteros
- Molecular Physiology and Biophysics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
| | - Tracy S Fitzgerald
- Mouse Auditory Testing Core, National Institute on Deafness and other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, United States.
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83
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Trouillet A, Miller KK, George SS, Wang P, Ali NES, Ricci A, Grillet N. Loxhd1 Mutations Cause Mechanotransduction Defects in Cochlear Hair Cells. J Neurosci 2021; 41:3331-3343. [PMID: 33707295 PMCID: PMC8051682 DOI: 10.1523/jneurosci.0975-20.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 02/22/2021] [Accepted: 03/02/2021] [Indexed: 12/27/2022] Open
Abstract
Sound detection happens in the inner ear via the mechanical deflection of the hair bundle of cochlear hair cells. The hair bundle is an apical specialization consisting of actin-filled membrane protrusions (called stereocilia) connected by tip links (TLs) that transfer the deflection force to gate the mechanotransduction channels. Here, we identified the hearing loss-associated Loxhd1/DFNB77 gene as being required for the mechanotransduction process. LOXHD1 consists of 15 polycystin lipoxygenase α-toxin (PLAT) repeats, which in other proteins can bind lipids and proteins. LOXHD1 was distributed along the length of the stereocilia. Two LOXHD1 mouse models with mutations in the 10th PLAT repeat exhibited mechanotransduction defects (in both sexes). While mechanotransduction currents in mutant inner hair cells (IHCs) were similar to wild-type levels in the first postnatal week, they were severely affected by postnatal day 11. The onset of the mechanotransduction phenotype was consistent with the temporal progression of postnatal LOXHD1 expression/localization in the hair bundle. The mechanotransduction defect observed in Loxhd1-mutant IHCs was not accompanied by a morphologic defect of the hair bundle or a reduction in TL number. Using immunolocalization, we found that two proteins of the upper and lower TL protein complexes (Harmonin and LHFPL5) were maintained in the mutants, suggesting that the mechanotransduction machinery was present but not activatable. This work identified a novel LOXHD1-dependent step in hair bundle development that is critical for mechanotransduction in mature hair cells as well as for normal hearing function in mice and humans.SIGNIFICANCE STATEMENT Hair cells detect sound-induced forces via the hair bundle, which consists of membrane protrusions connected by tip links. The mechanotransduction machinery forms protein complexes at the tip-link ends. The current study showed that LOXHD1, a multirepeat protein responsible for hearing loss in humans and mice when mutated, was required for hair-cell mechanotransduction, but only after the first postnatal week. Using immunochemistry, we demonstrated that this defect was not caused by the mislocalization of the tip-link complex proteins Harmonin or LHFPL5, suggesting that the mechanotransduction protein complexes were maintained. This work identified a new step in hair bundle development, which is critical for both hair-cell mechanotransduction and hearing.
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Affiliation(s)
- Alix Trouillet
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
| | - Katharine K Miller
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
| | - Shefin Sam George
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
| | - Pei Wang
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
| | - Noor-E-Seher Ali
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
| | - Anthony Ricci
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, California 94305
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Stanford University, Stanford, California 94305
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84
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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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Theophylline alleviates gentamicin-induced cytotoxicity to sensory hair cells by maintaining HDAC2 expression. Acta Histochem 2021; 123:151696. [PMID: 33652374 DOI: 10.1016/j.acthis.2021.151696] [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: 12/19/2020] [Revised: 02/13/2021] [Accepted: 02/18/2021] [Indexed: 11/22/2022]
Abstract
Sensorineural hearing loss is a health problem with global prevalence. Aminoglycoside antibiotics, for instance gentamicin, may cause ototoxicity in mammals as a result of apoptosis and elevated oxidative stress in cochlear hair cells. Our study aimed to examine the potential effects of theophylline, an HDAC2 agonist, on gentamicin-induced cytotoxicity to sensory hair cells. Mouse cochlear explants and HEI-OC1 cells were in vitro cultured and challenged by gentamicin to induce ototoxicity, with or without theophylline. Cochlear hair cells were evaluated by fluorescent microscopy, and their mechanotransduction was assessed by electrophysiology. Expression levels of HDAC2 and apoptosis pathway factors were also evaluated following gentamicin and theophylline treatments. The functional role of HDAC2 in this setting was investigated by siRNA targeted silencing. Theophylline protected cochlear hair cells from ototoxicity induced by gentamicin, in terms of preserving cochlear structure and mechanotransduction ability, and preventing the activation of the intrinsic apoptosis pathway dose-dependently. HDAC2 expression was downregulated by gentamicin, which could be restored by theophylline. HDAC2 silencing in HEI-OC1 cells negated the beneficial effect of theophylline against gentamicin-induced growth defect and apoptosis activation. Theophylline protects sensory hair cells from gentamicin ototoxicity by maintaining HDAC2 expression. Our study thereby discovers a critical role of HDAC2 in gentamicin-induced ototoxicity, which could shine light on potential therapeutic options for treatment against sensorineural hearing loss.
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86
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Effertz T, Moser T, Oliver D. Recent advances in cochlear hair cell nanophysiology: subcellular compartmentalization of electrical signaling in compact sensory cells. Fac Rev 2021; 9:24. [PMID: 33659956 PMCID: PMC7886071 DOI: 10.12703/r/9-24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In recent years, genetics, physiology, and structural biology have advanced into the molecular details of the sensory physiology of auditory hair cells. Inner hair cells (IHCs) and outer hair cells (OHCs) mediate two key functions: active amplification and non-linear compression of cochlear vibrations by OHCs and sound encoding by IHCs at their afferent synapses with the spiral ganglion neurons. OHCs and IHCs share some molecular physiology, e.g. mechanotransduction at the apical hair bundles, ribbon-type presynaptic active zones, and ionic conductances in the basolateral membrane. Unique features enabling their specific function include prestin-based electromotility of OHCs and indefatigable transmitter release at the highest known rates by ribbon-type IHC active zones. Despite their compact morphology, the molecular machineries that either generate electrical signals or are driven by these signals are essentially all segregated into local subcellular structures. This review provides a brief account on recent insights into the molecular physiology of cochlear hair cells with a specific focus on organization into membrane domains.
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Affiliation(s)
- Thomas Effertz
- InnerEarLab, Department of Otorhinolaryngology, University Medical Center Göttingen, 37099 Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany
- Auditory Neuroscience Group, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
- Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, 37075 Göttingen, Germany
| | - Dominik Oliver
- Institute for Physiology and Pathophysiology, Philipps University, Deutschhausstraße 2, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Universities of Marburg and Giessen, Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodelling, GRK 2213, Philipps University, Marburg, Germany
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87
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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: 35] [Impact Index Per Article: 11.7] [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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88
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Alternative Splicing of Three Genes Encoding Mechanotransduction-Complex Proteins in Auditory Hair Cells. eNeuro 2021; 8:ENEURO.0381-20.2020. [PMID: 33509951 PMCID: PMC7920537 DOI: 10.1523/eneuro.0381-20.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/29/2020] [Accepted: 12/10/2020] [Indexed: 11/21/2022] Open
Abstract
The mechanotransduction (MT) complex in auditory hair cells converts the mechanical stimulation of sound waves into neural signals. Recently, the MT complex has been suggested to contain at least four distinct integral membrane proteins: protocadherin 15 (PCDH15), transmembrane channel-like protein 1 (TMC1), lipoma HMGIC fusion partner-like 5 (LHFPL5), and transmembrane inner ear protein (TMIE). However, the composition, function, and regulation of the MT-complex proteins remain incompletely investigated. Here, we report previously undescribed splicing isoforms of TMC1, LHFPL5, and TMIE. We identified four alternative splicing events for the genes encoding these three proteins by analyzing RNA-seq libraries of auditory hair cells from adult mice [over postnatal day (P)28], and we then verified the alternative splicing events by using RT-PCR and Sanger sequencing. Moreover, we examined the tissue-specific distribution, developmental expression patterns, and tonotopic gradient of the splicing isoforms by performing semiquantitative and quantitative real-time PCR (qRT-PCR), and we found that the alternative splicing of TMC1 and LHFPL5 is cochlear-specific and occurs in both neonatal and adult mouse cochleae. Our findings not only reveal the potential complexity of the MT-complex composition, but also provide critical insights for guiding future research on the function, regulation, and trafficking of TMC1, LHFPL5, and TMIE and on the clinical diagnosis of hearing loss related to aberrant splicing of these three key genes in hearing.
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89
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Li B, Li S, Yan Z. Axonemal Dynein DNAH5 is Required for Sound Sensation in Drosophila Larvae. Neurosci Bull 2021; 37:523-534. [PMID: 33570705 DOI: 10.1007/s12264-021-00631-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/09/2020] [Indexed: 11/29/2022] Open
Abstract
Chordotonal neurons are responsible for sound sensation in Drosophila. However, little is known about how they respond to sound with high sensitivity. Using genetic labeling, we found one of the Drosophila axonemal dynein heavy chains, CG9492 (DNAH5), was specifically expressed in larval chordotonal neurons and showed a distribution restricted to proximal cilia. While DNAH5 mutation did not affect the cilium morphology or the trafficking of Inactive, a candidate auditory transduction channel, larvae with DNAH5 mutation had reduced startle responses to sound at low and medium intensities. Calcium imaging confirmed that DNAH5 functioned autonomously in chordotonal neurons for larval sound sensation. Furthermore, disrupting DNAH5 resulted in a decrease of spike firing responses to low-level sound in chordotonal neurons. Intriguingly, DNAH5 mutant larvae displayed an altered frequency tuning curve of the auditory organs. All together, our findings support a critical role of DNAH5 in tuning the frequency selectivity and the sound sensitivity of larval auditory neurons.
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Affiliation(s)
- Bingxue Li
- State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Department of Physiology and Biophysics, Institute of Brain Science, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Songling Li
- State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Department of Physiology and Biophysics, Institute of Brain Science, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518132, China
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Department of Physiology and Biophysics, Institute of Brain Science, School of Life Sciences, Fudan University, Shanghai, 200438, China.
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518132, China.
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90
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Fan Y, Zou W, Liu J, Al-Sheikh U, Cheng H, Duan D, Du Chen, Liu S, Chen L, Xu J, Ruhomutally F, Kang L. Polymodal Functionality of C. elegans OLL Neurons in Mechanosensation and Thermosensation. Neurosci Bull 2021; 37:611-622. [PMID: 33555565 PMCID: PMC8099987 DOI: 10.1007/s12264-021-00629-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 08/25/2020] [Indexed: 12/04/2022] Open
Abstract
Sensory modalities are important for survival but the molecular mechanisms remain challenging due to the polymodal functionality of sensory neurons. Here, we report the C. elegans outer labial lateral (OLL) sensilla sensory neurons respond to touch and cold. Mechanosensation of OLL neurons resulted in cell-autonomous mechanically-evoked Ca2+ transients and rapidly-adapting mechanoreceptor currents with a very short latency. Mechanotransduction of OLL neurons might be carried by a novel Na+ conductance channel, which is insensitive to amiloride. The bona fide mechano-gated Na+-selective degenerin/epithelial Na+ channels, TRP-4, TMC, and Piezo proteins are not involved in this mechanosensation. Interestingly, OLL neurons also mediated cold but not warm responses in a cell-autonomous manner. We further showed that the cold response of OLL neurons is not mediated by the cold receptor TRPA-1 or the temperature-sensitive glutamate receptor GLR-3. Thus, we propose the polymodal functionality of OLL neurons in mechanosensation and cold sensation.
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Affiliation(s)
- Yuedan Fan
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Wenjuan Zou
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Jia Liu
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Hankui Cheng
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Duo Duan
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Du Chen
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Siyan Liu
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China
| | - Luyi Chen
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China
| | - Jilei Xu
- Department of Gastroenterology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China
| | - Firdosh Ruhomutally
- Department of Human Sciences and Psychology, University of South Africa (UNISA), Pretoria, 0003, South Africa
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310053, China. .,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310053, China.
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91
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Meng X, Mukherjee D, Kao JPY, Kanold PO. Early peripheral activity alters nascent subplate circuits in the auditory cortex. SCIENCE ADVANCES 2021; 7:eabc9155. [PMID: 33579707 PMCID: PMC7880598 DOI: 10.1126/sciadv.abc9155] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/28/2020] [Indexed: 05/10/2023]
Abstract
Cortical function can be shaped by sensory experience during a critical period. The onset of the critical period is thought to coincide with the onset of thalamocortical transmission to the thalamo-recipient layer 4 (L4). In early development, subplate neurons (SPNs), and not L4 neurons, are the first targets of thalamic afferents. SPNs are transiently involved in early development and are largely eliminated during development. Activation of L4 by thalamic afferents coincides with the opening of ear canal (~P11 in mice) and precedes the later critical period. Here, we show in mice that abolishing peripheral function or presenting sound stimuli even before P11 leads to bidirectionally altered functional connectivity of SPNs in auditory cortex. Thus, early sensory experience can sculpt subplate circuits before thalamocortical circuits to L4 are mature. Our results show that peripheral activity shapes cortical circuits in a sequential manner and from earlier ages than has been appreciated.
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Affiliation(s)
- Xiangying Meng
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Didhiti Mukherjee
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Patrick O Kanold
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.
- Department of Biology, University of Maryland, College Park, MD 20742, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA
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92
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Dianatpour M, Smith E, Hashemi SB, Farazifard MA, Nezafat N, Razban V, Mani A. Identification of homozygous mutations for hearing loss. Gene 2021; 778:145464. [PMID: 33524517 DOI: 10.1016/j.gene.2021.145464] [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: 05/16/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Hearing loss is the most common sensory disorder worldwide, affecting about 1 out of every 1000 newborns. The disease has major genetic components, and can be inherited as a single gene disorder either in autosomal dominant or recessive fashions. Due to the high rate of consanguineous unions, Iran has one of the highest prevalence of autosomal recessive nonsyndromic deafness (ARNSD) in the world. METHODS We carried out a genetic screening of ten Iranian kindreds with more than one offspring affected by ARNSD caused by consanguineous unions. Sanger sequencing and whole exome sequencing together with in silico 3D structure modeling and protein stability prediction were used to identify the underlying disease causing genes. CONCLUSION We identified the causes of deafness in all 10 kindred. In six kindreds homozygous mutations were identified in GJB2 gene by Sanger sequencing. By using whole exome sequencing (WES), a homozygous missense mutation was identified in ESRRB gene as the first ever reported disease gene in Iran. Also two novel homozygous frameshift and missense mutations were identified in MYO15A gene and one previously reported mutation in TMC1 gene in three independent kindred. Our study shows the efficacy of WES for unraveling new pathogenic mutations in ARNSD patients and expands the spectrum of genes contributing to ARNSD in the Iranian population. The findings of our study can facilitate future genetic screening of patients with ARNSD , early screening and optimal design of novel therapeutics.
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Affiliation(s)
- Mehdi Dianatpour
- Department of Medical Genetic, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran; Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Emily Smith
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University, School of Medicine, New Haven, CT, United States.
| | - Seyed Basir Hashemi
- Department of Otolaryngology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad A Farazifard
- Department of Medical Genetic, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Navid Nezafat
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Vahid Razban
- Stem Cells Technology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Molecular Medicine, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Arya Mani
- Department of Internal Medicine, Yale Cardiovascular Research Center, Yale University, School of Medicine, New Haven, CT, United States.
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93
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Fang XZ, Zhou T, Xu JQ, Wang YX, Sun MM, He YJ, Pan SW, Xiong W, Peng ZK, Gao XH, Shang Y. Structure, kinetic properties and biological function of mechanosensitive Piezo channels. Cell Biosci 2021; 11:13. [PMID: 33422128 PMCID: PMC7796548 DOI: 10.1186/s13578-020-00522-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/16/2020] [Indexed: 02/06/2023] Open
Abstract
Mechanotransduction couples mechanical stimulation with ion flux, which is critical for normal biological processes involved in neuronal cell development, pain sensation, and red blood cell volume regulation. Although they are key mechanotransducers, mechanosensitive ion channels in mammals have remained difficult to identify. In 2010, Coste and colleagues revealed a novel family of mechanically activated cation channels in eukaryotes, consisting of Piezo1 and Piezo2 channels. These have been proposed as the long-sought-after mechanosensitive cation channels in mammals. Piezo1 and Piezo2 exhibit a unique propeller-shaped architecture and have been implicated in mechanotransduction in various critical processes, including touch sensation, balance, and cardiovascular regulation. Furthermore, several mutations in Piezo channels have been shown to cause multiple hereditary human disorders, such as autosomal recessive congenital lymphatic dysplasia. Notably, mutations that cause dehydrated hereditary xerocytosis alter the rate of Piezo channel inactivation, indicating the critical role of their kinetics in normal physiology. Given the importance of Piezo channels in understanding the mechanotransduction process, this review focuses on their structural details, kinetic properties and potential function as mechanosensors. We also briefly review the hereditary diseases caused by mutations in Piezo genes, which is key for understanding the function of these proteins.
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Affiliation(s)
- Xiang-Zhi Fang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ting Zhou
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ji-Qian Xu
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Xin Wang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Miao-Miao Sun
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ya-Jun He
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shang-Wen Pan
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Xiong
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhe-Kang Peng
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xue-Hui Gao
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - You Shang
- Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. .,Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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94
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Wrobel C, Zafeiriou MP, Moser T. Understanding and treating paediatric hearing impairment. EBioMedicine 2021; 63:103171. [PMID: 33422987 PMCID: PMC7808910 DOI: 10.1016/j.ebiom.2020.103171] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/20/2020] [Accepted: 12/01/2020] [Indexed: 12/26/2022] Open
Abstract
Sensorineural hearing impairment is the most frequent form of hearing impairment affecting 1-2 in 1000 newborns and another 1 in 1000 adolescents. More than 50% of congenital hearing impairment is of genetic origin and some forms of monogenic deafness are likely targets for future gene therapy. Good progress has been made in clinical phenotyping, genetic diagnostics, and counselling. Disease modelling, e.g. in transgenic mice, has helped elucidate disease mechanisms underlying genetic hearing impairment and informed clinical phenotyping in recent years. Clinical management of paediatric hearing impairment involves hearing aids, cochlear or brainstem implants, signal-to-noise improvement in educational settings, speech therapy, and sign language. Cochlear implants, for example, have much improved the situation of profoundly hearing impaired and deaf children. Nonetheless there remains a major unmet clinical need for improving hearing restoration. Preclinical studies promise that we will witness clinical trials on gene therapy and a next generation of cochlear implants during the coming decade. Moreover, progress in generating sensory hair cells and neurons from stem cells spurs disease modelling, drug screening, and regenerative approaches. This review briefly summarizes the pathophysiology of paediatric hearing impairment and provides an update on the current preclinical development of innovative approaches toward improved hearing restoration.
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Affiliation(s)
- Christian Wrobel
- Department of Otolaryngology and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany; Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Germany
| | - Maria-Patapia Zafeiriou
- Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Germany; Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany
| | - Tobias Moser
- Multiscale Bioimaging Cluster of Excellence (MBExC), University of Göttingen, Germany; Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37099 Göttingen, Germany.
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95
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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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Gallo S, Trevisi P, Rigon C, Caserta E, Seif Ali D, Bovo R, Martini A, Cassina M. Auditory Outcome after Cochlear Implantation in Children with DFNB7/11 Caused by Pathogenic Variants in TMC1 Gene. Audiol Neurootol 2020; 26:157-163. [PMID: 33352559 DOI: 10.1159/000510156] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/14/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Non-syndromic hereditary hearing loss is characterized by extreme genetic heterogeneity. So far, more than 100 pathogenic or likely pathogenic variants in TMC1 gene have been reported in patients with autosomal recessive hearing loss (HL) DFNB7/11. The prevailing auditory phenotype of individuals with DFNB7/11 is congenital, profound, bilateral HL, but the functional outcome after cochlear implantation (CI) described in the literature is variable. The objective of this work is to evaluate the auditory outcome after CI in pediatric patients with DFNB7/11, born to non-consanguineous parents. METHODS A retrospective analysis of genetic and audiological data of DFNB7/11 patients followed up in a single Italian otolaryngology clinic was performed. Cases with biallelic pathogenic variants in TMC1 were selected from the cohort of children with non-syndromic hearing loss who had undergone CI and had been molecularly characterized by multigene panel testing. All patients underwent extensive audiological assessment, and the auditory outcome after CI was evaluated. RESULTS DFNB7/11 was diagnosed in a total of 3 patients from 2 non-consanguineous families; a novel disease-causing variant in TMC1 was detected [c.962G>A p.(Trp321*)]. All the affected children showed the typical DFNB7/11 phenotype characterized by prelingual, severe-to-profound HL. The patients showed an excellent functional outcome after CI; speech perception, nonverbal cognition, and speech performance were comparable to those of patients with DFNB1 deafness. DISCUSSION/CONCLUSION Our results do not support the variable auditory outcome reported in the literature, which may be affected by several social and environmental factors and by the genetic background.
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Affiliation(s)
- Samanta Gallo
- Otolaryngology Unit, Department of Neurosciences, University of Padova, Padova, Italy
| | - Patrizia Trevisi
- Otolaryngology Unit, Department of Neurosciences, University of Padova, Padova, Italy
| | - Chiara Rigon
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Ezio Caserta
- Otolaryngology Unit, Department of Neurosciences, University of Padova, Padova, Italy
| | - Dario Seif Ali
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Roberto Bovo
- Otolaryngology Unit, Department of Neurosciences, University of Padova, Padova, Italy
| | - Alessandro Martini
- Otolaryngology Unit, Department of Neurosciences, University of Padova, Padova, Italy
| | - Matteo Cassina
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy,
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Abstract
Mechanosensation such as touch, hearing and proprioception, is functionally regulated by mechano-gated ion channels through the process of transduction. Mechano-gated channels are a subtype of gated ion channels engaged in converting mechanical stimuli to chemical or electrical signals thereby modulating sensation. To date, a few families of mechano-gated channels (DEG/ENaC, TRPN, K2P, TMC and Piezo) have been identified in eukaryotes. Using a tractable genetic model organism Caenorhabditis elegans, the molecular mechanism of mechanosensation have been the focus of much research to comprehend the process of mechanotransduction. Comprising of almost all metazoans classes of ion channels, transporters and receptors, C. elegans is a powerful genetic model to explore mechanosensitive behaviors such as touch sensation and proprioception. The nematode relies primarily on its sensory abilities to survive in its natural environment. Genetic screening, calcium imaging and electrophysiological analysis have established that ENaC proteins and TRPN channel (TRP-4 protein) can characterize mechano-gated channels in C. elegans. A recent study reported that TMCs are likely the pore-forming subunit of a mechano-gated channel in C. elegans. Nevertheless, it still remains unclear whether Piezo as well as other candidate proteins can form mechano-gated channels in C. elegans.
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Affiliation(s)
- Umar Al-Sheikh
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Zhejiang, China
| | - Lijun Kang
- Department of Neurobiology and Department of Neurosurgery of the First Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Zhejiang, China
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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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Wu CJ, Li X, Sommers CL, Kurima K, Huh S, Bugos G, Dong L, Li W, Griffith AJ, Samelson LE. Expression of a TMC6-TMC8-CIB1 heterotrimeric complex in lymphocytes is regulated by each of the components. J Biol Chem 2020; 295:16086-16099. [PMID: 32917726 DOI: 10.1074/jbc.ra120.013045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 09/09/2020] [Indexed: 11/06/2022] Open
Abstract
The TMC genes encode a set of homologous transmembrane proteins whose functions are not well understood. Biallelic mutations in either TMC6 or TMC8 are detected in more than half of cases of the pre-malignant skin disease epidermodysplasia verruciformis (EV). It is controversial whether EV induced by mutations in TMC6 or TMC8 originates from keratinocyte or lymphocyte defects. Quantification of TMC6 and TMC8 RNA levels in various organs revealed that lymphoid tissues have the highest levels of expression of both genes, and custom antibodies confirmed protein expression in mouse lymphocytes. To study the function of these proteins we generated mice with targeted deletion mutant alleles of Tmc6 or Tmc8 Either TMC6 or TMC8 deficiency induced a reduction in apparent molecular weight and/or amount of the other TMC molecule. Co-immunoprecipitation experiments indicated that TMC6 and TMC8 formed a protein complex in mouse and human T cells. MS and biochemical analysis demonstrated that TMC6 and TMC8 additionally interacted with the CIB1 protein to form TMC6-TMC8-CIB1 trimers. We demonstrated that TMC6 and TMC8 regulated CIB1 levels by protecting CIB1 from ubiquitination and proteasomal degradation. Reciprocally, CIB1 was needed for stabilizing TMC6 and TMC8 levels. These results suggest why inactivating mutations in any of the three human genes leads to similar clinical presentations. We also demonstrated that TMC6 and TMC8 levels are drastically lower and the proteins are less active in regulating CIB1 in keratinocytes than in T cells. Our study suggests that defects in lymphocytes may contribute to the etiology and pathogenesis of EV.
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Affiliation(s)
- Chuan-Jin Wu
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Xing Li
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, USA
| | - Connie L Sommers
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Kiyoto Kurima
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, USA
| | - Sunmee Huh
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Grace Bugos
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Lijin Dong
- Genetic Engineering Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Wenmei Li
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA
| | - Andrew J Griffith
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, USA
| | - Lawrence E Samelson
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA.
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Abstract
The delivery of therapies to the cochlea is notoriously challenging. It is an organ protected by a number of barriers that need to be overcome in the drug delivery process. Additionally, there are multiple sites of possible damage within the cochlea. Despite the many potential sites of damage, acquired otologic insults preferentially damage a single location. While progress has been made in techniques for inner ear drug delivery, the current techniques remain non-specific and our ability to deliver therapies in a cell-specific manner are limited. Fortunately, there are proteins specific to various cell-types within the cochlea (e.g., hair cells, spiral ganglion cells, stria vascularis) that function as biomarkers of site-specific damage. These protein biomarkers have potential to serve as targets for cell-specific inner ear drug delivery. In this manuscript, we review the concept of biomarkers and targeted- inner ear drug delivery and the well-characterized protein biomarkers within each of the locations of interest within the cochlea. Our review will focus on targeted drug delivery in the setting of acquired otologic insults (e.g., ototoxicity, noise-induce hearing loss). The goal is not to discuss therapies to treat acquired otologic insults, rather, to establish potential concepts of how to deliver therapies in a targeted, cell-specific manner. Based on our review, it is clear that future of inner ear drug delivery is a discipline filled with potential that will require collaborative efforts among clinicians and scientists to optimize treatment of otologic insults. Graphical Abstract ![]()
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