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Yang TH, Hsu YC, Yeh P, Hung CJ, Tsai YF, Fang MC, Yen ACC, Chen LF, Pan JY, Wu CC, Liu TC, Chung FL, Yu WM, Lin SW. Critical role of hepsin/TMPRSS1 in hearing and tectorial membrane morphogenesis: Insights from transgenic mouse models. Hear Res 2024; 453:109134. [PMID: 39437584 DOI: 10.1016/j.heares.2024.109134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2024] [Revised: 10/15/2024] [Accepted: 10/17/2024] [Indexed: 10/25/2024]
Abstract
Mutations in various type II transmembrane serine protease (TMPRSS) family members are associated with non-syndromic hearing loss, with some mechanisms still unclear. For instance, the mechanism underlying profound hearing loss and tectorial membrane (TM) malformations in hepsin/TMPRSS1 knockout (KO) mice remains elusive. In this study, we confirmed significantly elevated hearing thresholds and abnormal TM morphology in hepsin KO mice, characterized by enlarged TM with gaps and detachment from the spiral limbus. Transgenic mouse lines were created to express either wild-type or a serine protease-dead mutant of human hepsin in the KO background. The Tg68;KO line, expressing moderate levels of wild-type human hepsin in the cochlea, showed partial restoration of hearing function. Conversely, the Tg5;KO or TgRS;KO lines, with undetectable hepsin or protease-dead hepsin, did not show such improvement. Histological analyses revealed that Tg68;KO mice, but not Tg5;KO or TgRS;KO mice, had a more compact TM structure, partially attached to the spiral limbus. These results indicate that hepsin expression levels correlate with improvements in hearing and TM morphology, and its protease activity is critical for these effects. Hepsin's role was further examined by studying its relationship with α-tectorin (TECTA) and β-tectorin (TECTB), non-collagenous proteins crucial for TM formation. Hepsin was co-expressed with TECTA and TECTB in the developing cochlear epithelium. Immunostaining showed decreased levels of TECTA and TECTB in hepsin KO TM, partially restored in Tg68;KO mice. These findings suggest that hepsin is essential for proper TM morphogenesis and auditory function, potentially by proteolytic processing/maturation of TECTA and TECTB and their incorporation into the TM.
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Affiliation(s)
- Ting-Hua Yang
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yu-Chen Hsu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Liver Disease Prevention and Treatment Research Foundation, Taiwan
| | - Peng Yeh
- Department of Otolaryngology, Far Eastern Memorial Hospital, New Taipei City, Taiwan
| | - Chia-Jui Hung
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Fei Tsai
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Mo-Chu Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | | | - Li-Fu Chen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jhih-Yu Pan
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Tien-Chen Liu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Fong-Ling Chung
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Wei-Ming Yu
- Department of Biology, Loyola University Chicago, Chicago, IL, USA.
| | - Shu-Wha Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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2
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Schmidt HF, Darwin CB, Sundaram MV. The Pax transcription factor EGL-38 links EGFR signaling to assembly of a cell-type specific apical extracellular matrix in the Caenorhabditis elegans vulva. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.04.611291. [PMID: 39282387 PMCID: PMC11398461 DOI: 10.1101/2024.09.04.611291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
The surface of epithelial tissues is covered by an apical extracellular matrix (aECM). The aECMs of different tissues have distinct compositions to serve distinct functions, yet how a particular cell type assembles the proper aECM is not well understood. We used the cell-type specific matrix of the C. elegans vulva to investigate the connection between cell identity and matrix assembly. The vulva is an epithelial tube composed of seven cell types descending from EGFR/Ras-dependent (1°) and Notch-dependent (2°) lineages. Vulva aECM contains multiple Zona Pellucida domain (ZP) proteins, which are a common component of aECMs across life. ZP proteins LET-653 and CUTL-18 assemble on 1° cell surfaces, while NOAH-1 assembles on a subset of 2° surfaces. All three ZP genes are broadly transcribed, indicating that cell-type specific ZP assembly must be determined by features of the destination cell surface. The paired box (Pax) transcription factor EGL-38 promotes assembly of 1° matrix and prevents inappropriate assembly of 2° matrix, suggesting that EGL-38 promotes expression of one or more ZP matrix organizers. Our results connect the known signaling pathways and various downstream effectors to EGL-38/Pax expression and the ZP matrix component of vulva cell fate execution. We propose that dedicated transcriptional networks may contribute to cell-appropriate assembly of aECM in many epithelial organs.
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Affiliation(s)
- Helen F Schmidt
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Chelsea B Darwin
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Meera V Sundaram
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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3
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Ghosh N, Treisman JE. Apical cell expansion maintained by Dusky-like establishes a scaffold for corneal lens morphogenesis. SCIENCE ADVANCES 2024; 10:eado4167. [PMID: 39167639 PMCID: PMC11338227 DOI: 10.1126/sciadv.ado4167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 07/11/2024] [Indexed: 08/23/2024]
Abstract
The Drosophila corneal lens is entirely composed of chitin and other apical extracellular matrix components, and it is not known how it acquires the biconvex shape that enables it to focus light onto the retina. We show here that the zona pellucida domain-containing protein Dusky-like is essential for normal corneal lens morphogenesis. Dusky-like transiently localizes to the expanded apical surfaces of the corneal lens-secreting cells and prevents them from undergoing apical constriction and apicobasal contraction. Dusky-like also controls the arrangement of two other zona pellucida domain proteins, Dumpy and Piopio, external to the developing corneal lens. Loss of either dusky-like or dumpy delays chitin accumulation and disrupts the outer surface of the corneal lens. We find that artificially inducing apical constriction by activating myosin contraction is sufficient to similarly alter chitin deposition and corneal lens morphology. These results demonstrate the importance of cell shape in controlling the morphogenesis of overlying apical extracellular matrix structures such as the corneal lens.
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Affiliation(s)
- Neha Ghosh
- Department of Cell Biology, NYU Grossman School of Medicine, 540 First Avenue, New York, NY 10016, USA
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Manley GA. Conditions Underlying the Appearance of Spontaneous Otoacoustic Emissions in Mammals. J Assoc Res Otolaryngol 2024; 25:303-311. [PMID: 38760548 PMCID: PMC11349964 DOI: 10.1007/s10162-024-00950-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 04/28/2024] [Indexed: 05/19/2024] Open
Abstract
Across the wide range of land vertebrate species, spontaneous otoacoustic emissions (SOAE) are common, but not always found. The reasons for the differences between species of the various groups in their emission patterns are often not well understood, particularly within mammals. This review examines the question as to what determines in mammals whether SOAE are emitted or not, and suggests that the coupling between hair-cell regions diminishes when the space constant of frequency distribution becomes larger. The reduced coupling is assumed to result in a greater likelihood of SOAE being emitted.
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Affiliation(s)
- Geoffrey A Manley
- Cochlear and Auditory Brainstem Physiology, Department of Neuroscience, School of Medicine and Health Sciences, Cluster of Excellence "Hearing4all", Carl von Ossietzky University Oldenburg, 26129, Oldenburg, Germany.
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5
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Melrose J. Keratan sulfate, an electrosensory neurosentient bioresponsive cell instructive glycosaminoglycan. Glycobiology 2024; 34:cwae014. [PMID: 38376199 PMCID: PMC10987296 DOI: 10.1093/glycob/cwae014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/21/2024] Open
Abstract
The roles of keratan sulfate (KS) as a proton detection glycosaminoglycan in neurosensory processes in the central and peripheral nervous systems is reviewed. The functional properties of the KS-proteoglycans aggrecan, phosphacan, podocalyxcin as components of perineuronal nets in neurosensory processes in neuronal plasticity, cognitive learning and memory are also discussed. KS-glycoconjugate neurosensory gels used in electrolocation in elasmobranch fish species and KS substituted mucin like conjugates in some tissue contexts in mammals need to be considered in sensory signalling. Parallels are drawn between KS's roles in elasmobranch fish neurosensory processes and its roles in mammalian electro mechanical transduction of acoustic liquid displacement signals in the cochlea by the tectorial membrane and stereocilia of sensory inner and outer hair cells into neural signals for sound interpretation. The sophisticated structural and functional proteins which maintain the unique high precision physical properties of stereocilia in the detection, transmittance and interpretation of acoustic signals in the hearing process are important. The maintenance of the material properties of stereocilia are essential in sound transmission processes. Specific, emerging roles for low sulfation KS in sensory bioregulation are contrasted with the properties of high charge density KS isoforms. Some speculations are made on how the molecular and electrical properties of KS may be of potential application in futuristic nanoelectronic, memristor technology in advanced ultrafast computing devices with low energy requirements in nanomachines, nanobots or molecular switches which could be potentially useful in artificial synapse development. Application of KS in such innovative areas in bioregulation are eagerly awaited.
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Affiliation(s)
- James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Raymond Purves Laboratory, Institute of Bone and Joint Research, Kolling Institute of Medical Research, Northern Sydney Local Health District, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
- Sydney Medical School, Northern, University of Sydney at Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
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Ghosh N, Treisman JE. Apical cell expansion maintained by Dusky-like establishes a scaffold for corneal lens morphogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.17.575959. [PMID: 38293108 PMCID: PMC10827211 DOI: 10.1101/2024.01.17.575959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The biconvex shape of the Drosophila corneal lens, which enables it to focus light onto the retina, arises by organized assembly of chitin and other apical extracellular matrix components. We show here that the Zona Pellucida domain-containing protein Dusky-like is essential for normal corneal lens morphogenesis. Dusky-like transiently localizes to the expanded apical surfaces of the corneal lens-secreting cells, and in its absence, these cells undergo apical constriction and apicobasal contraction. Dusky-like also controls the arrangement of two other Zona Pellucida-domain proteins, Dumpy and Piopio, external to the developing corneal lens. Loss of either dusky-like or dumpy delays chitin accumulation and disrupts the outer surface of the corneal lens. Artificially inducing apical constriction with constitutively active Myosin light chain kinase is sufficient to similarly alter chitin deposition and corneal lens morphology. These results demonstrate the importance of cell shape for the morphogenesis of overlying apical extracellular matrix structures.
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Niazi A, Kim JA, Kim DK, Lu D, Sterin I, Park J, Park S. Microvilli regulate the release modes of alpha-tectorin to organize the domain-specific matrix architecture of the tectorial membrane. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.04.574255. [PMID: 38260557 PMCID: PMC10802356 DOI: 10.1101/2024.01.04.574255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The tectorial membrane (TM) is an apical extracellular matrix (ECM) in the cochlea essential for auditory transduction. The TM exhibits highly ordered domain-specific architecture. Alpha-tectorin/TECTA is a glycosylphosphatidylinositol (GPI)-anchored ECM protein essential for TM organization. Here, we identified that TECTA is released by distinct modes: proteolytic shedding by TMPRSS2 and GPI-anchor-dependent release from the microvillus tip. In the medial/limbal domain, proteolytically shed TECTA forms dense fibers. In the lateral/body domain produced by the supporting cells displaying dense microvilli, the proteolytic shedding restricts TECTA to the microvillus tip and compartmentalizes the collagen-binding site. The tip-localized TECTA, in turn, is released in a GPI-anchor-dependent manner to form collagen-crosslinking fibers, required for maintaining the spacing and parallel organization of collagen fibrils. Overall, we showed that distinct release modes of TECTA determine the domain-specific organization pattern, and the microvillus coordinates the release modes along its membrane to organize the higher-order ECM architecture.
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Affiliation(s)
- Ava Niazi
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
- Neuroscience Program, University of Utah, Salt Lake City, Utah, USA
| | - Ju Ang Kim
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
- Current affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Dong-Kyu Kim
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
- Current affiliation: Genetics & Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Di Lu
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| | - Igal Sterin
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| | - Joosang Park
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
| | - Sungjin Park
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, USA
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8
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Warren B, Eberl D. What can insects teach us about hearing loss? J Physiol 2024; 602:297-316. [PMID: 38128023 DOI: 10.1113/jp281281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Over the last three decades, insects have been utilized to provide a deep and fundamental understanding of many human diseases and disorders. Here, we present arguments for insects as models to understand general principles underlying hearing loss. Despite ∼600 million years since the last common ancestor of vertebrates and invertebrates, we share an overwhelming degree of genetic homology particularly with respect to auditory organ development and maintenance. Despite the anatomical differences between human and insect auditory organs, both share physiological principles of operation. We explain why these observations are expected and highlight areas in hearing loss research in which insects can provide insight. We start by briefly introducing the evolutionary journey of auditory organs, the reasons for using insect auditory organs for hearing loss research, and the tools and approaches available in insects. Then, the first half of the review focuses on auditory development and auditory disorders with a genetic cause. The second half analyses the physiological and genetic consequences of ageing and short- and long-term changes as a result of noise exposure. We finish with complex age and noise interactions in auditory systems. In this review, we present some of the evidence and arguments to support the use of insects to study mechanisms and potential treatments for hearing loss in humans. Obviously, insects cannot fully substitute for all aspects of human auditory function and loss of function, although there are many important questions that can be addressed in an animal model for which there are important ethical, practical and experimental advantages.
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Affiliation(s)
- Ben Warren
- Neurogenetics Group, College of Life Sciences, University of Leicester, Leicester, UK
| | - Daniel Eberl
- Department of Biology, University of Iowa, Iowa City, IA, USA
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9
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Adams JRG, Pooranachithra M, Jyo EM, Zheng SL, Goncharov A, Crew JR, Kramer JM, Jin Y, Ernst AM, Chisholm AD. Nanoscale patterning of collagens in C. elegans apical extracellular matrix. Nat Commun 2023; 14:7506. [PMID: 37980413 PMCID: PMC10657453 DOI: 10.1038/s41467-023-43058-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 10/30/2023] [Indexed: 11/20/2023] Open
Abstract
Apical extracellular matrices (aECMs) are complex extracellular compartments that form important interfaces between animals and their environment. In the adult C. elegans cuticle, layers are connected by regularly spaced columnar structures known as struts. Defects in struts result in swelling of the fluid-filled medial cuticle layer ('blistering', Bli). Here we show that three cuticle collagens BLI-1, BLI-2, and BLI-6, play key roles in struts. BLI-1 and BLI-2 are essential for strut formation whereas activating mutations in BLI-6 disrupt strut formation. BLI-1, BLI-2, and BLI-6 precisely colocalize to arrays of puncta in the adult cuticle, corresponding to struts, initially deposited in diffuse stripes adjacent to cuticle furrows. They eventually exhibit tube-like morphology, with the basal ends of BLI-containing struts contact regularly spaced holes in the cuticle. Genetic interaction studies indicate that BLI strut patterning involves interactions with other cuticle components. Our results reveal strut formation as a tractable example of precise aECM patterning at the nanoscale.
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Affiliation(s)
- Jennifer R G Adams
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Murugesan Pooranachithra
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Erin M Jyo
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Sherry Li Zheng
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Alexandr Goncharov
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Jennifer R Crew
- Northwestern University School of Medicine, Department of Cell and Molecular Biology, Chicago, IL, 60611, USA
| | - James M Kramer
- Northwestern University School of Medicine, Department of Cell and Molecular Biology, Chicago, IL, 60611, USA
| | - Yishi Jin
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Andreas M Ernst
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Andrew D Chisholm
- Department of Cell and Developmental Biology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA.
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA.
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Abstract
Orchestration of protein production and degradation and the regulation of protein lifetimes play a central role in many basic biological processes. Nearly all mammalian proteins are replenished by protein turnover in waves of synthesis and degradation. Protein lifetimes in vivo are typically measured in days, but a small number of extremely long-lived proteins (ELLPs) persist for months or even years. ELLPs are rare in all tissues but are enriched in tissues containing terminally differentiated post-mitotic cells and extracellular matrix. Consistently, emerging evidence suggests that the cochlea may be particularly enriched in ELLPs. Damage to ELLPs in specialized cell types, such as crystallin in the lens cells of the eye, causes organ failure such as cataracts. Similarly, damage to cochlear ELLPs is likely to occur with many insults, including acoustic overstimulation, drugs, anoxia, and antibiotics, and may play an underappreciated role in hearing loss. Furthermore, hampered protein degradation may contribute to acquired hearing loss. In this review, I highlight our knowledge of the lifetimes of cochlear proteins with an emphasis on ELLPs and the potential contribution that impaired cochlear protein degradation has on acquired hearing loss and the emerging relevance of ELLPs.
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Affiliation(s)
- Jeffrey N Savas
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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11
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Xie Z, Ma XH, Bai QF, Tang J, Sun JH, Jiang F, Guo W, Wang CM, Yang R, Wen YC, Wang FY, Chen YX, Zhang H, He DZ, Kelley MW, Yang S, Zhang WJ. ZBTB20 is essential for cochlear maturation and hearing in mice. Proc Natl Acad Sci U S A 2023; 120:e2220867120. [PMID: 37279265 PMCID: PMC10268240 DOI: 10.1073/pnas.2220867120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 04/25/2023] [Indexed: 06/08/2023] Open
Abstract
The mammalian cochlear epithelium undergoes substantial remodeling and maturation before the onset of hearing. However, very little is known about the transcriptional network governing cochlear late-stage maturation and particularly the differentiation of its lateral nonsensory region. Here, we establish ZBTB20 as an essential transcription factor required for cochlear terminal differentiation and maturation and hearing. ZBTB20 is abundantly expressed in the developing and mature cochlear nonsensory epithelial cells, with transient expression in immature hair cells and spiral ganglion neurons. Otocyst-specific deletion of Zbtb20 causes profound deafness with reduced endolymph potential in mice. The subtypes of cochlear epithelial cells are normally generated, but their postnatal development is arrested in the absence of ZBTB20, as manifested by an immature appearance of the organ of Corti, malformation of tectorial membrane (TM), a flattened spiral prominence (SP), and a lack of identifiable Boettcher cells. Furthermore, these defects are related with a failure in the terminal differentiation of the nonsensory epithelium covering the outer border Claudius cells, outer sulcus root cells, and SP epithelial cells. Transcriptome analysis shows that ZBTB20 regulates genes encoding for TM proteins in the greater epithelial ridge, and those preferentially expressed in root cells and SP epithelium. Our results point to ZBTB20 as an essential regulator for postnatal cochlear maturation and particularly for the terminal differentiation of cochlear lateral nonsensory domain.
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Affiliation(s)
- Zhifang Xie
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai200092, China
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Xian-Hua Ma
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Qiu-Fang Bai
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
| | - Jie Tang
- Department of Physiology, Southern Medical University, Guangzhou, Guangdong510515, China
| | - Jian-He Sun
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Fei Jiang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Institute of Early Life Health, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai200092, China
| | - Wei Guo
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Chen-Ma Wang
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
| | - Rui Yang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Yin-Chuan Wen
- Department of Physiology, Southern Medical University, Guangzhou, Guangdong510515, China
| | - Fang-Yuan Wang
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Yu-Xia Chen
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - Hai Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
| | - David Z. He
- Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE68178
| | | | - Shiming Yang
- Senior Department of Otolaryngology-Head and Neck Surgery, National Clinical Research Center for Otolaryngologic Diseases, the Sixth Medical Center of PLA General Hospital, Beijing100141, China
| | - Weiping J. Zhang
- Department of Pathophysiology, Naval Medical University, Shanghai200433, China
- NHC Key Laboratory of Hormones and Development, Chu Hsien-I Memorial Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin300134, China
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12
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de Sousa Lobo Ferreira Querido R, Ji X, Lakha R, Goodyear RJ, Richardson GP, Vizcarra CL, Olson ES. Visualizing Collagen Fibrils in the Cochlea's Tectorial and Basilar Membranes Using a Fluorescently Labeled Collagen-Binding Protein Fragment. J Assoc Res Otolaryngol 2023; 24:147-157. [PMID: 36725777 PMCID: PMC10121988 DOI: 10.1007/s10162-023-00889-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/16/2023] [Indexed: 02/03/2023] Open
Abstract
PURPOSE A probe that binds to unfixed collagen fibrils was used to image the shapes and fibrous properties of the TM and BM. The probe (CNA35) is derived from the bacterial adhesion protein CNA. We present confocal images of hydrated gerbil TM, BM, and other cochlear structures stained with fluorescently labeled CNA35. A primary purpose of this article is to describe the use of the CNA35 collagen probe in the cochlea. METHODS Recombinant poly-histidine-tagged CNA35 was expressed in Escherichia coli, purified by cobalt-affinity chromatography, fluorescence labeled, and further purified by gel filtration chromatography. Cochleae from freshly harvested gerbil bullae were irrigated with and then incubated in CNA35 for periods ranging from 2 h - overnight. The cochleae were fixed, decalcified, and dissected. Isolated cochlear turns were imaged by confocal microscopy. RESULTS The CNA35 probe stained the BM and TM, and volumetric imaging revealed the shape of these structures and the collagen fibrils within them. The limbal zone of the TM stained intensely. In samples from the cochlear base, intense staining was detected on the side of the TM that faces hair cells. In the BM pectinate zone, staining was intense at the upper and lower boundaries. The BM arcuate zone was characterized by a prominent longitudinal collagenous structure. The spiral ligament, limbus and lamina stained for collagen, and within the spiral limbus the habenula perforata were outlined with intense staining. CONCLUSION The CNA35 probe provides a unique and useful view of collagenous structures in the cochlea.
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Affiliation(s)
| | - Xiang Ji
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
- Department of Chemistry, Barnard College, New York, NY, USA
| | - Rabina Lakha
- Department of Chemistry, Barnard College, New York, NY, USA
| | - Richard J Goodyear
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
| | - Guy P Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
| | | | - Elizabeth S Olson
- Department of Otolaryngology, Head and Neck Surgery, Columbia University, New York, NY, USA.
- Department of Biomedical Engineering, Columbia University, New York, NY, USA.
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Fung W, Tan TM, Kolotuev I, Heiman MG. A sex-specific switch in a single glial cell patterns the apical extracellular matrix. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.17.533199. [PMID: 36993293 PMCID: PMC10055199 DOI: 10.1101/2023.03.17.533199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Apical extracellular matrix (aECM) constitutes the interface between every tissue and the outside world. It is patterned into diverse tissue-specific structures through unknown mechanisms. Here, we show that a male-specific genetic switch in a single C. elegans glial cell patterns the aECM into a ∼200 nm pore, allowing a male sensory neuron to access the environment. We find that this glial sex difference is controlled by factors shared with neurons ( mab-3, lep-2, lep-5 ) as well as previously unidentified regulators whose effects may be glia-specific ( nfya-1, bed-3, jmjd-3.1 ). The switch results in male-specific expression of a Hedgehog-related protein, GRL-18, that we discover localizes to transient nanoscale rings at sites of aECM pore formation. Blocking male-specific gene expression in glia prevents pore formation, whereas forcing male-specific expression induces an ectopic pore. Thus, a switch in gene expression in a single cell is necessary and sufficient to pattern aECM into a specific structure.
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Affiliation(s)
- Wendy Fung
- Department of Genetics, Blavatnik Institute, Harvard Medical School and Boston Children’s Hospital, Boston, MA 02115, USA
| | - Taralyn M. Tan
- Department of Genetics, Blavatnik Institute, Harvard Medical School and Boston Children’s Hospital, Boston, MA 02115, USA
| | - Irina Kolotuev
- Electron Microscopy Facility, University of Lausanne, 1015 Lausanne, Switzerland
| | - Maxwell G. Heiman
- Department of Genetics, Blavatnik Institute, Harvard Medical School and Boston Children’s Hospital, Boston, MA 02115, USA
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Impaired tectorial membrane and ribbon synapse maturation in the cochlea of mice with congenital hypothyroidism. Biochem Biophys Res Commun 2023; 655:68-74. [PMID: 36933309 DOI: 10.1016/j.bbrc.2023.03.026] [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: 02/19/2023] [Revised: 03/01/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
Thyroid hormone deficiency can lead to abnormal auditory development of varying severity. Retardation of morphological development, including delays in degeneration of Kölliker's organ and subsequent delayed formation of the inner sulcus, along with delayed opening of the tunnel of Corti and malformation of the tectorial membrane, was consistently observed in an antithyroid drug-induced congenital hypothyroidism rodent model. Abnormal morphological development could partly explain impaired adult auditory function. However, whether the development of inner hair cell ribbon synapses is influenced by hypothyroidism remains unclear. In the present study, we characterize the normal degeneration pattern of Kölliker's organ along the basal-to-apical axis. Then, we verified the retardation of morphological development in congenital hypothyroid mice. Using this model, we found that twisted collagen is present in the major tectorial membrane and delayed separation from supporting cells affects the minor tectorial membrane. Finally, we found that the number of synaptic ribbons was not significantly altered but the ribbon synapse maturation process was significantly impaired in congenital hypothyroid mice. We conclude that thyroid hormone is involved in structural development of the tectorial membrane and the ribbon synapse maturation process.
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McGovern MM, Hartman B, Thawani A, Maunsell H, Zhang H, Yousaf R, Heller S, Stone J, Groves AK. Fbxo2 CreERT2: A new model for targeting cells in the neonatal and mature inner ear. Hear Res 2023; 428:108686. [PMID: 36587458 PMCID: PMC9840692 DOI: 10.1016/j.heares.2022.108686] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 12/12/2022] [Accepted: 12/26/2022] [Indexed: 12/28/2022]
Abstract
The mammalian inner ear contains six sensory patches that allow detection of auditory stimuli as well as movement and balance. Much research has focused on the organ of Corti, the sensory organ of the cochlea that detects sound. Unfortunately, these cells are difficult to access in vivo, especially in the mature animal, but the development of genetically modified mouse models, including Cre/Lox mice, has improved the ability to label, purify or manipulate these cells. Here, we describe a new tamoxifen-inducible CreER mouse line, the Fbxo2CreERT2 mouse, that can be used to specifically manipulate cells throughout the cochlear duct of the neonatal and mature cochlear epithelium. In vestibular sensory epithelia, Fbxo2CreERT2-mediated recombination occurs in many hair cells and more rarely in supporting cells of neonatal and adult mice, with a higher rate of Fbxo2CreERT2 induction in type 1 versus type 2 hair cells in adults. Fbxo2CreERT2 mice, therefore, are a new tool for the specific manipulation of epithelial cells of the inner ear and targeted manipulation of vestibular type 1 hair cells.
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Affiliation(s)
- Melissa M McGovern
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States.
| | - Byron Hartman
- Department of Otolaryngology, Stanford University, Stanford, CA 94305, United States
| | - Ankita Thawani
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States
| | - Helen Maunsell
- Program in Development, Disease Models and Therapeutics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States
| | - Hongyuan Zhang
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States
| | - Rizwan Yousaf
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States
| | - Stefan Heller
- Department of Otolaryngology, Stanford University, Stanford, CA 94305, United States
| | - Jennifer Stone
- Department of Otolaryngology-Head and Neck Surgery, Virginia Merrill Bloedel Hearing Research Center, University of Washington School of Medicine, Seattle, WA 98195, United States
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States; Program in Development, Disease Models and Therapeutics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States; Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, United States
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16
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Gioacchini FM, Pisani D, Viola P, Astorina A, Scarpa A, Libonati FA, Tulli M, Re M, Chiarella G. Diabetes Mellitus and Hearing Loss: A Complex Relationship. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59020269. [PMID: 36837470 PMCID: PMC9959034 DOI: 10.3390/medicina59020269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/18/2023] [Accepted: 01/26/2023] [Indexed: 02/03/2023]
Abstract
Background and Objectives: Discussion is open about the relationship between diabetes (DM) and hearing loss (HL). There is a lot of evidence in the literature suggesting a causal link between these conditions, beyond being considered simple comorbidities. The difficulty in identifying populations free from confounding factors makes it difficult to reach definitive conclusions on the pathophysiological mechanisms at play. Nonetheless, there is numerous evidence that demonstrates how the population affected by DM is more affected by sensorineural HL (SNHL) and exhibit a higher prevalence of idiopathic sudden sensorineural HL (ISSNHL). Materials and Methods: Articles reporting potentially relevant information were reviewed, and the most significant results are discussed in this article. Starting from the possible mechanisms relating to auditory impairment in the diabetic condition, this article summarizes the studies on auditory evaluation in subjects with DM1 and DM2 and addresses the relationship between DM and ISSNHL. Results: DM is considered a risk factor for SNHL, although some studies have reported no relationship when the associations were adjusted for age, gender, and hypertension. Macro and microvascular insults that cause decreased blood flow, oxygen exchange, and ion transport are major complications of hypertension and DM and can have a direct effect on the sensory and support cells of the cochlea. Conclusions: Given the difficulty of carrying out studies on populations without confounding factors, new laboratory studies are strongly required to clarify which specific physiopathological mechanisms underlie the diabetic damage caused to the hearing organs and how pharmacological management may contribute to counteracting the pathophysiological effects of the diabetic condition on the auditory system.
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Affiliation(s)
- Federico Maria Gioacchini
- ENT Unit, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, 60121 Ancona, Italy
| | - Davide Pisani
- Unit of Audiology, Regional Centre of Cochlear Implants and ENT Diseases, Department of Experimental and Clinical Medicine, Magna Graecia University, 88100 Catanzaro, Italy
| | - Pasquale Viola
- Unit of Audiology, Regional Centre of Cochlear Implants and ENT Diseases, Department of Experimental and Clinical Medicine, Magna Graecia University, 88100 Catanzaro, Italy
- Correspondence: ; Tel.: +39-096-1364-7124
| | - Alessia Astorina
- Unit of Audiology, Regional Centre of Cochlear Implants and ENT Diseases, Department of Experimental and Clinical Medicine, Magna Graecia University, 88100 Catanzaro, Italy
| | - Alfonso Scarpa
- Department of Medicine and Surgery, University of Salerno, 84084 Fisciano, Italy
| | | | - Michele Tulli
- ENT Unit, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, 60121 Ancona, Italy
| | - Massimo Re
- ENT Unit, Department of Clinical and Molecular Sciences, Polytechnic University of Marche, 60121 Ancona, Italy
| | - Giuseppe Chiarella
- Unit of Audiology, Regional Centre of Cochlear Implants and ENT Diseases, Department of Experimental and Clinical Medicine, Magna Graecia University, 88100 Catanzaro, Italy
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Ayukawa T, Akiyama M, Hozumi Y, Ishimoto K, Sasaki J, Senoo H, Sasaki T, Yamazaki M. Tissue flow regulates planar cell polarity independently of the Frizzled core pathway. Cell Rep 2022; 40:111388. [PMID: 36130497 DOI: 10.1016/j.celrep.2022.111388] [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: 08/24/2021] [Revised: 07/16/2022] [Accepted: 08/29/2022] [Indexed: 11/27/2022] Open
Abstract
Planar cell polarity (PCP) regulates the orientation of external structures. A core group of proteins that includes Frizzled forms the heart of the PCP regulatory system. Other PCP mechanisms that are independent of the core group likely exist, but their underlying mechanisms are elusive. Here, we show that tissue flow is a mechanism governing core group-independent PCP on the Drosophila notum. Loss of core group function only slightly affects bristle orientation in the adult central notum. This near-normal PCP results from tissue flow-mediated rescue of random bristle orientation during the pupal stage. Manipulation studies suggest that tissue flow can orient bristles in the opposite direction to the flow. This process is independent of the core group and implies that the apical extracellular matrix functions like a "comb" to align bristles. Our results reveal the significance of cooperation between tissue dynamics and extracellular substances in PCP establishment.
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Affiliation(s)
- Tomonori Ayukawa
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Masakazu Akiyama
- Meiji Institute for Advanced Study of Mathematical Sciences, Meiji University, Tokyo 164-8525, Japan; Faculty of Science, Academic Assembly, University of Toyama, Toyama 930-8555, Japan
| | - Yasukazu Hozumi
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Kenta Ishimoto
- Research Institute for Mathematical Sciences, Kyoto University, Kyoto 606-8502, Japan
| | - Junko Sasaki
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Haruki Senoo
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan
| | - Takehiko Sasaki
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo 113-8510, Japan
| | - Masakazu Yamazaki
- Department of Cell Biology and Morphology, Akita University Graduate School of Medicine, Akita 010-8543, Japan; Japan Science and Technology Agency, PRESTO, Saitama 332-0012, Japan.
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Jeng JY, Carlton AJ, Goodyear RJ, Chinowsky C, Ceriani F, Johnson SL, Sung TC, Dayn Y, Richardson GP, Bowl MR, Brown SD, Manor U, Marcotti W. AAV-mediated rescue of Eps8 expression in vivo restores hair-cell function in a mouse model of recessive deafness. Mol Ther Methods Clin Dev 2022; 26:355-370. [PMID: 36034774 PMCID: PMC9382420 DOI: 10.1016/j.omtm.2022.07.012] [Citation(s) in RCA: 2] [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: 04/30/2022] [Accepted: 07/15/2022] [Indexed: 11/24/2022]
Abstract
The transduction of acoustic information by hair cells depends upon mechanosensitive stereociliary bundles that project from their apical surface. Mutations or absence of the stereociliary protein EPS8 cause deafness in humans and mice, respectively. Eps8 knockout mice (Eps8 -/- ) have hair cells with immature stereocilia and fail to become sensory receptors. Here, we show that exogenous delivery of Eps8 using Anc80L65 in P1-P2 Eps8 -/- mice in vivo rescued the hair bundle structure of apical-coil hair cells. Rescued hair bundles correctly localize EPS8, WHIRLIN, MYO15, and BAIAP2L2, and generate normal mechanoelectrical transducer currents. Inner hair cells with normal-looking stereocilia re-expressed adult-like basolateral ion channels (BK and KCNQ4) and have normal exocytosis. The number of hair cells undergoing full recovery was not sufficient to rescue hearing in Eps8 -/- mice. Adeno-associated virus (AAV)-transduction of P3 apical-coil and P1-P2 basal-coil hair cells does not rescue hair cells, nor does Anc80L65-Eps8 delivery in adult Eps8 -/- mice. We propose that AAV-induced gene-base therapy is an efficient strategy to recover the complex hair-cell defects in Eps8 -/- mice. However, this therapeutic approach may need to be performed in utero since, at postnatal ages, Eps8 -/- hair cells appear to have matured or accumulated damage beyond the point of repair.
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Affiliation(s)
- Jing-Yi Jeng
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Adam J. Carlton
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Richard J. Goodyear
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Colbie Chinowsky
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Federico Ceriani
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
| | - Stuart L. Johnson
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Tsung-Chang Sung
- Transgenic Core, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yelena Dayn
- Transgenic Core, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Guy P. Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Michael R. Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD UK
| | - Steve D.M. Brown
- Mammalian Genetics Unit, MRC Harwell Institute, Harwell Campus, Oxfordshire OX11 0RD UK
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Walter Marcotti
- School of Bioscience, University of Sheffield, Sheffield S10 2TN, UK
- Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
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Li H, Staxäng K, Hodik M, Melkersson KG, Rask-Andersen M, Rask-Andersen H. Regeneration in the Auditory Organ in Cuban and African Dwarf Crocodiles (Crocodylus rhombifer and Osteolaemus tetraspis) Can We Learn From the Crocodile How to Restore Our Hearing? Front Cell Dev Biol 2022; 10:934571. [PMID: 35859896 PMCID: PMC9289536 DOI: 10.3389/fcell.2022.934571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/08/2022] [Indexed: 11/16/2022] Open
Abstract
Background: In several non-mammalian species, auditory receptors undergo cell renewal after damage. This has raised hope of finding new options to treat human sensorineural deafness. Uncertainty remains as to the triggering mechanisms and whether hair cells are regenerated even under normal conditions. In the present investigation, we explored the auditory organ in the crocodile to validate possible ongoing natural hair cell regeneration. Materials and Methods: Two male Cuban crocodiles (Crocodylus rhombifer) and an adult male African Dwarf crocodile (Osteolaemus tetraspis) were analyzed using transmission electron microscopy and immunohistochemistry using confocal microscopy. The crocodile ears were fixed in formaldehyde and glutaraldehyde and underwent micro-computed tomography (micro-CT) and 3D reconstruction. The temporal bones were drilled out and decalcified. Results: The crocodile papilla basilaris contained tall (inner) and short (outer) hair cells surrounded by a mosaic of tightly connected supporting cells coupled with gap junctions. Afferent neurons with and without ribbon synapses innervated both hair cell types. Supporting cells occasionally showed signs of trans-differentiation into hair cells. They expressed the MAFA and SOX2 transcription factors. Supporting cells contained organelles that may transfer genetic information between cells, including the efferent nerve fibers during the regeneration process. The tectorial membrane showed signs of being replenished and its architecture being sculpted by extracellular exosome-like proteolysis. Discussion: Crocodilians seem to produce new hair cells during their life span from a range of supporting cells. Imposing efferent nerve fibers may play a role in regeneration and re-innervation of the auditory receptors, possibly triggered by apoptotic signals from wasted hair cells. Intercellular signaling may be accomplished by elaborate gap junction and organelle systems, including neural emperipolesis. Crocodilians seem to restore and sculpt their tectorial membranes throughout their lives.
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Affiliation(s)
- Hao Li
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Karin Staxäng
- The Rudbeck TEM Laboratory, BioVis Platform, Uppsala University, Uppasala, Swedan
| | - Monika Hodik
- The Rudbeck TEM Laboratory, BioVis Platform, Uppsala University, Uppasala, Swedan
| | | | - Mathias Rask-Andersen
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
- *Correspondence: Helge Rask-Andersen,
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20
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Zhang D, Wu J, Yuan Y, Li X, Gao X, Han M, Gao S, Huang S, Dai P. A novel missense variant in CEACAM16 gene causes autosomal dominant nonsyndromic hearing loss. Ann Hum Genet 2022; 86:207-217. [PMID: 35292975 PMCID: PMC9314904 DOI: 10.1111/ahg.12463] [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: 10/04/2021] [Revised: 02/13/2022] [Accepted: 02/16/2022] [Indexed: 11/27/2022]
Abstract
AbstractAimAutosomal dominant non‐syndromic hearing loss is a common sensorineural disorder with extremely high genetic heterogeneity. CEA antigen‐related cell adhesion molecule 16(CEACAM16)is a secreted glycoprotein encoded by the CEACAM16 gene. Mutations in CEACAM16 lead to autosomal dominant non‐syndromic hearing loss in humans, due defects in the tectorial membrane of the inner ear. Here we reported a novel missense variant in CEACAM16 gene causes autosomal dominant non‐syndromic hearing loss.Material and methodsA four‐generation Chinese family affected by late‐onset and progressive hearing loss was enrolled in this study. The proband was analyzed by targeted next‐generation sequencing and bioinformatic analysis. And in vitro experiments were performed in overexpressed transfected HEK293T cells to investigate the pathogenesis of the mutant protein.ResultsWe identified a novel missense variant in the CEACAM16 gene c.763A>G; (p.Arg255Gly) as causing autosomal dominant non‐syndromic hearing loss in the Chinese family. Using Western blot analysis, ELISA, and immunofluorescence we found increased expression level of the secreted mutant CEACAM16 protein, both intracellularly and extracellularly, compared with wild type CEACAM16 protein.ConclusionOur study showed that the p.Arg255Gly variant leads to increased secretion of mutant CEACAM16 protein, with potential deleterious effect to the function of the protein. Our findings expand the mutation spectrum of CEACAM16, and further the understanding CEACAM16 function and implications in disease.
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Affiliation(s)
- Dejun Zhang
- College of Otolaryngology Head and Neck SurgeryChinese PLA General HospitalBeijingChina
- Department of Otolaryngology Head and Neck SurgeryThe Second Hospital of Jilin UniversityChangchunChina
- State Key Lab of Hearing Science, Ministry of EducationNational Clinical Research Center for Otolaryngologic DiseasesBeijingChina
- Beijing Key Lab of Hearing Impairment for Prevention and TreatmentBeijingChina
| | - Jie Wu
- College of Otolaryngology Head and Neck SurgeryChinese PLA General HospitalBeijingChina
- State Key Lab of Hearing Science, Ministry of EducationNational Clinical Research Center for Otolaryngologic DiseasesBeijingChina
- Beijing Key Lab of Hearing Impairment for Prevention and TreatmentBeijingChina
| | - Yongyi Yuan
- College of Otolaryngology Head and Neck SurgeryChinese PLA General HospitalBeijingChina
- State Key Lab of Hearing Science, Ministry of EducationNational Clinical Research Center for Otolaryngologic DiseasesBeijingChina
- Beijing Key Lab of Hearing Impairment for Prevention and TreatmentBeijingChina
| | - Xiaohong Li
- Department of Otolaryngology, Head and Neck Surgery, National Children's Medical Center/Beijing Children's HospitalCapital Medical UniversityBeijingPR China
| | - Xue Gao
- Department of OtolaryngologyPLA Rocket Force Characteristic Medical CenterBeijingChina
| | - Mingyu Han
- College of Otolaryngology Head and Neck SurgeryChinese PLA General HospitalBeijingChina
- State Key Lab of Hearing Science, Ministry of EducationNational Clinical Research Center for Otolaryngologic DiseasesBeijingChina
- Beijing Key Lab of Hearing Impairment for Prevention and TreatmentBeijingChina
| | - Song Gao
- Department of OtolaryngologySouth‐East Hospital Affiliated to Xiamen UniversityZhangzhouChina
| | - Shasha Huang
- College of Otolaryngology Head and Neck SurgeryChinese PLA General HospitalBeijingChina
- State Key Lab of Hearing Science, Ministry of EducationNational Clinical Research Center for Otolaryngologic DiseasesBeijingChina
- Beijing Key Lab of Hearing Impairment for Prevention and TreatmentBeijingChina
| | - Pu Dai
- College of Otolaryngology Head and Neck SurgeryChinese PLA General HospitalBeijingChina
- State Key Lab of Hearing Science, Ministry of EducationNational Clinical Research Center for Otolaryngologic DiseasesBeijingChina
- Beijing Key Lab of Hearing Impairment for Prevention and TreatmentBeijingChina
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21
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Kelley MW. Cochlear Development; New Tools and Approaches. Front Cell Dev Biol 2022; 10:884240. [PMID: 35813214 PMCID: PMC9260282 DOI: 10.3389/fcell.2022.884240] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/19/2022] [Indexed: 12/21/2022] Open
Abstract
The sensory epithelium of the mammalian cochlea, the organ of Corti, is comprised of at least seven unique cell types including two functionally distinct types of mechanosensory hair cells. All of the cell types within the organ of Corti are believed to develop from a population of precursor cells referred to as prosensory cells. Results from previous studies have begun to identify the developmental processes, lineage restrictions and signaling networks that mediate the specification of many of these cell types, however, the small size of the organ and the limited number of each cell type has hampered progress. Recent technical advances, in particular relating to the ability to capture and characterize gene expression at the single cell level, have opened new avenues for understanding cellular specification in the organ of Corti. This review will cover our current understanding of cellular specification in the cochlea, discuss the most commonly used methods for single cell RNA sequencing and describe how results from a recent study using single cell sequencing provided new insights regarding cellular specification.
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22
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Iwasa KH. Of mice and chickens: Revisiting the RC time constant problem. Hear Res 2021; 423:108422. [PMID: 34965897 DOI: 10.1016/j.heares.2021.108422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 11/30/2022]
Abstract
Avian hair cells depend on electrical resonance for frequency selectivity. The upper bound of the frequency range is limited by the RC time constant of hair cells because the sharpness of tuning requires that the resonance frequency must be lower than the RC roll-off frequency. In contrast, tuned mechanical vibration of the inner ear is the basis of frequency selectivity of the mammalian ear. This mechanical vibration is supported by outer hair cells (OHC) with their electromotility (or piezoelectricity), which is driven by the receptor potential. Thus, it is also subjected to the RC time constant problem. Association of OHCs with a system with mechanical resonance leads to piezoelectric resonance. This resonance can nullify the membrane capacitance and solves the RC time constant problem for OHCs. Therefore, avian and mammalian ears solve the same problem in the opposite way.
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Affiliation(s)
- Kuni H Iwasa
- NIDCD, National Institutes of Health, Bethesda, MD 20892, USA.
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23
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Zona Pellucida Genes and Proteins: Essential Players in Mammalian Oogenesis and Fertility. Genes (Basel) 2021; 12:genes12081266. [PMID: 34440440 PMCID: PMC8391237 DOI: 10.3390/genes12081266] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/03/2021] [Accepted: 08/10/2021] [Indexed: 12/17/2022] Open
Abstract
All mammalian oocytes and eggs are surrounded by a relatively thick extracellular matrix (ECM), the zona pellucida (ZP), that plays vital roles during oogenesis, fertilization, and preimplantation development. Unlike ECM surrounding somatic cells, the ZP is composed of only a few glycosylated proteins, ZP1–4, that are unique to oocytes and eggs. ZP1–4 have a large region of polypeptide, the ZP domain (ZPD), consisting of two subdomains, ZP-N and ZP-C, separated by a short linker region, that plays an essential role in polymerization of nascent ZP proteins into crosslinked fibrils. Both subdomains adopt immunoglobulin (Ig)-like folds for their 3-dimensional structure. Mouse and human ZP genes are encoded by single-copy genes located on different chromosomes and are highly expressed in the ovary by growing oocytes during late stages of oogenesis. Genes encoding ZP proteins are conserved among mammals, and their expression is regulated by cis-acting sequences located close to the transcription start-site and by the same/similar trans-acting factors. Nascent ZP proteins are synthesized, packaged into vesicles, secreted into the extracellular space, and assembled into long, crosslinked fibrils that have a structural repeat, a ZP2-ZP3 dimer, and constitute the ZP matrix. Fibrils are oriented differently with respect to the oolemma in the inner and outer layers of the ZP. Sequence elements in the ZPD and the carboxy-terminal propeptide of ZP1–4 regulate secretion and assembly of nascent ZP proteins. The presence of both ZP2 and ZP3 is required to assemble ZP fibrils and ZP1 and ZP4 are used to crosslink the fibrils. Inactivation of mouse ZP genes by gene targeting has a detrimental effect on ZP formation around growing oocytes and female fertility. Gene sequence variations in human ZP genes due to point, missense, or frameshift mutations also have a detrimental effect on ZP formation and female fertility. The latter mutations provide additional support for the role of ZPD subdomains and other regions of ZP polypeptide in polymerization of human ZP proteins into fibrils and matrix.
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Jeng JY, Harasztosi C, Carlton A, Corns L, Marchetta P, Johnson SL, Goodyear RJ, Legan KP, Rüttiger L, Richardson GP, Marcotti W. MET currents and otoacoustic emissions from mice with a detached tectorial membrane indicate the extracellular matrix regulates Ca 2+ near stereocilia. J Physiol 2021; 599:2015-2036. [PMID: 33559882 PMCID: PMC7612128 DOI: 10.1113/jp280905] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/03/2021] [Indexed: 10/11/2023] Open
Abstract
KEY POINTS The aim was to determine whether detachment of the tectorial membrane (TM) from the organ of Corti in Tecta/Tectb-/- mice affects the biophysical properties of cochlear outer hair cells (OHCs). Tecta/Tectb-/- mice have highly elevated hearing thresholds, but OHCs mature normally. Mechanoelectrical transducer (MET) channel resting open probability (Po ) in mature OHC is ∼50% in endolymphatic [Ca2+ ], resulting in a large standing depolarizing MET current that would allow OHCs to act optimally as electromotile cochlear amplifiers. MET channel resting Po in vivo is also high in Tecta/Tectb-/- mice, indicating that the TM is unlikely to statically bias the hair bundles of OHCs. Distortion product otoacoustic emissions (DPOAEs), a readout of active, MET-dependent, non-linear cochlear amplification in OHCs, fail to exhibit long-lasting adaptation to repetitive stimulation in Tecta/Tectb-/- mice. We conclude that during prolonged, sound-induced stimulation of the cochlea the TM may determine the extracellular Ca2+ concentration near the OHC's MET channels. ABSTRACT The tectorial membrane (TM) is an acellular structure of the cochlea that is attached to the stereociliary bundles of the outer hair cells (OHCs), electromotile cells that amplify motion of the cochlear partition and sharpen its frequency selectivity. Although the TM is essential for hearing, its role is still not fully understood. In Tecta/Tectb-/- double knockout mice, in which the TM is not coupled to the OHC stereocilia, hearing sensitivity is considerably reduced compared with that of wild-type animals. In vivo, the OHC receptor potentials, assessed using cochlear microphonics, are symmetrical in both wild-type and Tecta/Tectb-/- mice, indicating that the TM does not bias the hair bundle resting position. The functional maturation of hair cells is also unaffected in Tecta/Tectb-/- mice, and the resting open probability of the mechanoelectrical transducer (MET) channel reaches values of ∼50% when the hair bundles of mature OHCs are bathed in an endolymphatic-like Ca2+ concentration (40 μM) in vitro. The resultant large MET current depolarizes OHCs to near -40 mV, a value that would allow optimal activation of the motor protein prestin and normal cochlear amplification. Although the set point of the OHC receptor potential transfer function in vivo may therefore be determined primarily by endolymphatic Ca2+ concentration, repetitive acoustic stimulation fails to produce adaptation of MET-dependent otoacoustic emissions in vivo in the Tecta/Tectb-/- mice. Therefore, the TM is likely to contribute to the regulation of Ca2+ levels around the stereocilia, and thus adaptation of the OHC MET channel during prolonged sound stimulation.
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Affiliation(s)
- Jing-Yi Jeng
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Csaba Harasztosi
- Department of Otolaryngology Head & Neck Surgery, THRC, University of Tübingen, 72076 Tübingen, Germany
| | - Adam Carlton
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Laura Corns
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Philine Marchetta
- Department of Otolaryngology Head & Neck Surgery, THRC, University of Tübingen, 72076 Tübingen, Germany
| | - Stuart L. Johnson
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | | | - Kevin P. Legan
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Lukas Rüttiger
- Department of Otolaryngology Head & Neck Surgery, THRC, University of Tübingen, 72076 Tübingen, Germany
| | - Guy P. Richardson
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
| | - Walter Marcotti
- Department of Biomedical Science, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, S10 2TN, UK
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25
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Li Zheng S, Adams JG, Chisholm AD. Form and function of the apical extracellular matrix: new insights from Caenorhabditis elegans, Drosophila melanogaster, and the vertebrate inner ear. Fac Rev 2020; 9:27. [PMID: 33659959 PMCID: PMC7886070 DOI: 10.12703/r/9-27] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Apical extracellular matrices (aECMs) are the extracellular layers on the apical sides of epithelia. aECMs form the outer layer of the skin in most animals and line the luminal surface of internal tubular epithelia. Compared to the more conserved basal ECMs (basement membranes), aECMs are highly diverse between tissues and between organisms and have been more challenging to understand at mechanistic levels. Studies in several genetic model organisms are revealing new insights into aECM composition, biogenesis, and function and have begun to illuminate common principles and themes of aECM organization. There is emerging evidence that, in addition to mechanical or structural roles, aECMs can participate in reciprocal signaling with associated epithelia and other cell types. Studies are also revealing mechanisms underlying the intricate nanopatterns exhibited by many aECMs. In this review, we highlight recent findings from well-studied model systems, including the external cuticle and ductal aECMs of Caenorhabditis elegans, Drosophila melanogaster, and other insects and the internal aECMs of the vertebrate inner ear.
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Affiliation(s)
- Sherry Li Zheng
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jennifer Gotenstein Adams
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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Liu W, Glueckert R, Schrott-Fischer A, Rask-Andersen H. Human cochlear microanatomy – an electron microscopy and super-resolution structured illumination study and review. HEARING BALANCE AND COMMUNICATION 2020. [DOI: 10.1080/21695717.2020.1807259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Head and Neck Surgery, section of Otolaryngology, Uppsala University Hospital, Department of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, section of Otolaryngology, Uppsala University Hospital, Department of Otolaryngology, Uppsala University Hospital, Uppsala, Sweden
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27
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Abstract
The cochlea, a coiled structure located in the ventral region of the inner ear, acts as the primary structure for the perception of sound. Along the length of the cochlear spiral is the organ of Corti, a highly derived and rigorously patterned sensory epithelium that acts to convert auditory stimuli into neural impulses. The development of the organ of Corti requires a series of inductive events that specify unique cellular characteristics and axial identities along its three major axes. Here, we review recent studies of the cellular and molecular processes regulating several aspects of cochlear development, such as axial patterning, cochlear outgrowth and cellular differentiation. We highlight how the precise coordination of multiple signaling pathways is required for the successful formation of a complete organ of Corti.
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Affiliation(s)
- Elizabeth Carroll Driver
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Matthew W Kelley
- Laboratory of Cochlear Development, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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28
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Yamoah EN, Li M, Shah A, Elliott KL, Cheah K, Xu PX, Phillips S, Young SM, Eberl DF, Fritzsch B. Using Sox2 to alleviate the hallmarks of age-related hearing loss. Ageing Res Rev 2020; 59:101042. [PMID: 32173536 PMCID: PMC7261488 DOI: 10.1016/j.arr.2020.101042] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 02/07/2023]
Abstract
Age-related hearing loss (ARHL) is the most prevalent sensory deficit. ARHL reduces the quality of life of the growing population, setting seniors up for the enhanced mental decline. The size of the needy population, the structural deficit, and a likely research strategy for effective treatment of chronic neurosensory hearing in the elderly are needed. Although there has been profound advancement in auditory regenerative research, there remain multiple challenges to restore hearing loss. Thus, additional investigations are required, using novel tools. We propose how the (1) flat epithelium, remaining after the organ of Corti has deteriorated, can be converted to the repaired-sensory epithelium, using Sox2. This will include (2) developing an artificial gene regulatory network transmitted by (3) large viral vectors to the flat epithelium to stimulate remnants of the organ of Corti to restore hair cells. We hope to unite with our proposal toward the common goal, eventually restoring a functional human hearing organ by transforming the flat epithelial cells left after the organ of Corti loss.
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Affiliation(s)
- Ebenezer N Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, USA
| | - Mark Li
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, USA
| | - Anit Shah
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, USA
| | - Karen L Elliott
- Department of Biology, CLAS, University of Iowa, Iowa City, USA
| | - Kathy Cheah
- Department of Biochemistry, Hong Kong University, Hong Kong, China
| | - Pin-Xian Xu
- Department of Biochemistry, Hong Kong University, Hong Kong, China
| | - Stacia Phillips
- Department of Biochemistry, Hong Kong University, Hong Kong, China
| | - Samuel M Young
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, USA; Department of Otolaryngology, Iowa Neuroscience Institute, University of Iowa, Iowa City, USA
| | - Daniel F Eberl
- Department of Biology, CLAS, University of Iowa, Iowa City, USA
| | - Bernd Fritzsch
- Department of Biology, CLAS, University of Iowa, Iowa City, USA.
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Compound Phenotype Due to Recessive Variants in LARP7 and OTOG Genes Disclosed by an Integrated Approach of SNP-Array and Whole Exome Sequencing. Genes (Basel) 2020; 11:genes11040379. [PMID: 32244554 PMCID: PMC7230222 DOI: 10.3390/genes11040379] [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: 02/24/2020] [Revised: 03/25/2020] [Accepted: 03/29/2020] [Indexed: 12/20/2022] Open
Abstract
Neurodevelopmental disorders are a challenge in medical genetics due to genetic heterogeneity and complex genotype-phenotype correlations. For this reason, the resolution of single cases not belonging to well-defined syndromes often requires an integrated approach of multiple whole-genome technologies. Such an approach has also unexpectedly revealed a complex molecular basis in an increasing number of patients, for whom the original suspect of a pleiotropic syndrome has been resolved as the summation effect of multiple genes. We describe a 10-year-old boy, the third son of first-cousin parents, with global developmental delay, facial dysmorphism, and bilateral deafness. SNP-array analysis revealed regions of homozygosity (ROHs) in multiple chromosome regions. Whole-exome sequencing prioritized on gene-mapping into the ROHs showed homozygosity for the likely pathogenic c.1097_1098delAG p. (Arg366Thrfs*2) frameshift substitution in LARP7 and the likely pathogenic c.5743C>T p.(Arg1915*) nonsense variant in OTOG. Recessive variants in LARP7 cause Alazami syndrome, while variants in OTOG cause an extremely rare autosomal recessive form of neurosensorial deafness. Previously unreported features were acrocyanosis and palmoplantar hyperhidrosis. This case highlights the utility of encouraging technological updates in medical genetics laboratories involved in the study of neurodevelopmental disorders and integrating laboratory outputs with the competencies of next-generation clinicians.
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Schade-Mann T, Münkner S, Eckrich T, Engel J. Calcium signaling in interdental cells during the critical developmental period of the mouse cochlea. Hear Res 2020; 389:107913. [PMID: 32120242 DOI: 10.1016/j.heares.2020.107913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 02/04/2020] [Accepted: 02/07/2020] [Indexed: 11/18/2022]
Abstract
The tectorial membrane (TM), a complex acellular structure that covers part of the organ of Corti and excites outer hair cells, is required for normal hearing. It consists of collagen fibrils and various glycoproteins, which are synthesized in embryonic and postnatal development by different cochlear cell types including the interdental cells (IDCs). At its modiolar side, the TM is fixed to the apical surfaces of IDCs, which form the covering epithelium of the spiral limbus. We performed confocal membrane imaging and Ca2+ imaging in IDCs of the developing mouse cochlea from birth to postnatal day 18 (P18). Using the fluorescent membrane markers FM 4-64 and CellMask™ Deep Red on explanted whole-mount cochlear epithelium, we identified the morphology of IDCs at different z-levels of the spiral limbus. Ca2+ imaging of Fluo-8 AM-loaded cochlear epithelia revealed spontaneous intracellular Ca2+ transients in IDCs at P0/1, P4/5, and P18. Their relative frequency was lowest on P0/1, increased by a factor of 12.5 on P4/5 and decreased to twice the initial value on P18. At all three ages, stimulation of IDCs with the trinucleotides ATP and UTP at 1 and 10 μM elicited Ca2+ transients of varying amplitude and shape. Before the onset of hearing, IDCs responded with robust Ca2+ oscillations. At P18, after the onset of hearing, ATP stimulation either caused Ca2+ oscillations or an initial Ca2+ peak followed by a plateau while the UTP response was unchanged from that at pre-hearing stage. Parameters of spontaneous and nucleotide-evoked Ca2+ transients such as amplitude, decay time and duration were markedly reduced during cochlear development, whereas the kinetics of the Ca2+ rise did not show relevant changes. Whether low-frequency spontaneous Ca2+ transients are necessary for the formation and maintenance of the tectorial membrane e.g. by regulating gene transcription needs to be elucidated in further studies.
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Affiliation(s)
- Thore Schade-Mann
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany; Department of Otolaryngology, Head and Neck Surgery, Tübingen University Medical Centre, Germany
| | - Stefan Münkner
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany
| | - Tobias Eckrich
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany
| | - Jutta Engel
- Dept. of Biophysics & CIPMM, Hearing Research, Saarland University, Homburg, Germany.
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31
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Bullen A, Forge A, Wright A, Richardson GP, Goodyear RJ, Taylor R. Ultrastructural defects in stereocilia and tectorial membrane in aging mouse and human cochleae. J Neurosci Res 2019; 98:1745-1763. [DOI: 10.1002/jnr.24556] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 10/24/2019] [Accepted: 10/28/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Anwen Bullen
- UCL Ear Institute University College London London UK
| | - Andrew Forge
- UCL Ear Institute University College London London UK
| | | | - Guy P. Richardson
- Sussex Neuroscience School of Life Sciences University of Sussex Falmer, Brighton UK
| | - Richard J. Goodyear
- Sussex Neuroscience School of Life Sciences University of Sussex Falmer, Brighton UK
| | - Ruth Taylor
- UCL Ear Institute University College London London UK
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32
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Kim DK, Kim JA, Park J, Niazi A, Almishaal A, Park S. The release of surface-anchored α-tectorin, an apical extracellular matrix protein, mediates tectorial membrane organization. SCIENCE ADVANCES 2019; 5:eaay6300. [PMID: 31807709 PMCID: PMC6881170 DOI: 10.1126/sciadv.aay6300] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
The tectorial membrane (TM) is an apical extracellular matrix (ECM) that hovers over the cochlear sensory epithelium and plays an essential role in auditory transduction. The TM forms facing the luminal endolymph-filled space and exhibits complex ultrastructure. Contrary to the current extracellular assembly model, which posits that secreted collagen fibrils and ECM components self-arrange in the extracellular space, we show that surface tethering of α-tectorin (TECTA) via a glycosylphosphatidylinositol anchor is essential to prevent diffusion of secreted TM components. In the absence of surface-tethered TECTA, collagen fibrils aggregate randomly and fail to recruit TM glycoproteins. Conversely, conversion of TECTA into a transmembrane form results in a layer of collagens on the epithelial surface that fails to form a multilayered structure. We propose a three-dimensional printing model for TM morphogenesis: A new layer of ECM is printed on the cell surface concomitant with the release of a preestablished layer to generate the multilayered TM.
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Affiliation(s)
- Dong-Kyu Kim
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ju Ang Kim
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Joosang Park
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ava Niazi
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ali Almishaal
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT 84112, USA
| | - Sungjin Park
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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33
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Goodyear RJ, Cheatham MA, Naskar S, Zhou Y, Osgood RT, Zheng J, Richardson GP. Accelerated Age-Related Degradation of the Tectorial Membrane in the Ceacam16βgal/βgal Null Mutant Mouse, a Model for Late-Onset Human Hereditary Deafness DFNB113. Front Mol Neurosci 2019; 12:147. [PMID: 31249509 PMCID: PMC6582249 DOI: 10.3389/fnmol.2019.00147] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 05/20/2019] [Indexed: 12/20/2022] Open
Abstract
CEACAM16 is a non-collagenous protein of the tectorial membrane, an extracellular structure of the cochlea essential for normal hearing. Dominant and recessive mutations in CEACAM16 have been reported to cause postlingual and progressive forms of deafness in humans. In a previous study of young Ceacam16βgal/βgal null mutant mice on a C57Bl/6J background, the incidence of spontaneous otoacoustic emissions (SOAEs) was greatly increased relative to Ceacam16+/+ and Ceacam16+/βgal mice, but auditory brain-stem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) were near normal, indicating auditory thresholds were not significantly affected. To determine if the loss of CEACAM16 leads to hearing loss at later ages in this mouse line, cochlear structure and auditory function were examined in Ceacam16+/+, Ceacam16+/βgal and Ceacam16βgal/βgal mice at 6 and 12 months of age and compared to that previously described at 1 month. Analysis of older Ceacam16βgal/βgal mice reveals a progressive loss of matrix from the core of the tectorial membrane that is more extensive in the apical, low-frequency regions of the cochlea. In Ceacam16βgal/βgal mice at 6-7 months, the DPOAE magnitude at 2f1-f2 and the incidence of SOAEs both decrease relative to young animals. By ∼12 months, SOAEs and DPOAEs are not detected in Ceacam16βgal/βgal mice and ABR thresholds are increased by up to ∼40 dB across frequency, despite a complement of hair cells similar to that present in Ceacam16+/+ mice. Although SOAE incidence decreases with age in Ceacam16βgal/βgal mice, it increases in aging heterozygous Ceacam16+/βgal mice and is accompanied by a reduction in the accumulation of CEACAM16 in the tectorial membrane relative to controls. An apically-biased loss of matrix from the core of the tectorial membrane, similar to that observed in young Ceacam16βgal/βgal mice, is also seen in Ceacam16+/+ and Ceacam16+/βgal mice, and other strains of wild-type mice, but at much later ages. The loss of Ceacam16 therefore accelerates age-related degeneration of the tectorial membrane leading, as in humans with mutations in CEACAM16, to a late-onset progressive form of hearing loss.
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Affiliation(s)
- Richard J. Goodyear
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Mary Ann Cheatham
- The Knowles Hearing Center, Northwestern University, Evanston, IL, United States
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Souvik Naskar
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Yingjie Zhou
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Richard T. Osgood
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Jing Zheng
- The Knowles Hearing Center, Northwestern University, Evanston, IL, United States
- Department of Otolaryngology – Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Guy P. Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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Coate TM, Scott MK, Gurjar MC. Current concepts in cochlear ribbon synapse formation. Synapse 2019; 73:e22087. [PMID: 30592086 PMCID: PMC6573016 DOI: 10.1002/syn.22087] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022]
Abstract
In mammals, hair cells and spiral ganglion neurons (SGNs) in the cochlea together are sophisticated "sensorineural" structures that transduce auditory information from the outside world into the brain. Hair cells and SGNs are joined by glutamatergic ribbon-type synapses composed of a molecular machinery rivaling in complexity the mechanoelectric transduction components found at the apical side of the hair cell. The cochlear hair cell ribbon synapse has received much attention lately because of recent and important findings related to its damage (sometimes termed "synaptopathy") as a result of noise overexposure. During development, ribbon synapses between type I SGNs and inner hair cells form in the time window between birth and hearing onset and is a process coordinated with type I SGN myelination, spontaneous activity, synaptic pruning, and innervation by efferents. In this review, we highlight new findings regarding the diversity of type I SGNs and inner hair cell synapses, and the molecular mechanisms of selective hair cell targeting. Also discussed are cell adhesion molecules and protein constituents of the ribbon synapse, and how these factors participate in ribbon synapse formation. We also note interesting new insights into the morphological development of type II SGNs, and the potential for cochlear macrophages as important players in protecting SGNs. We also address recent studies demonstrating that the structural and physiological profiles of the type I SGNs do not reach full maturity until weeks after hearing onset, suggesting a protracted development that is likely modulated by activity.
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Affiliation(s)
- Thomas M. Coate
- Georgetown University, Department of Biology, 37th and O St. NW. Washington, DC. 20007. USA
| | - M. Katie Scott
- Department of Biological Sciences and Purdue Institute of Integrative Neuroscience, Purdue University, West Lafayette, Indiana 47907. USA
| | - Mansa C. Gurjar
- Georgetown University, Department of Biology, 37th and O St. NW. Washington, DC. 20007. USA
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35
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Melrose J. Functional Consequences of Keratan Sulfate Sulfation in Electrosensory Tissues and in Neuronal Regulation. ACTA ACUST UNITED AC 2019; 3:e1800327. [PMID: 32627425 DOI: 10.1002/adbi.201800327] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/16/2019] [Indexed: 12/20/2022]
Abstract
Keratan sulfate (KS) is a functional electrosensory and neuro-instructive molecule. Recent studies have identified novel low sulfation KS in auditory and sensory tissues such as the tectorial membrane of the organ of Corti and the Ampullae of Lorenzini in elasmobranch fish. These are extremely sensitive proton gradient detection systems that send signals to neural interfaces to facilitate audition and electrolocation. High and low sulfation KS have differential functional roles in song learning in the immature male zebra song-finch with high charge density KS in song nuclei promoting brain development and cognitive learning. The conductive properties of KS are relevant to the excitable neural phenotype. High sulfation KS interacts with a large number of guidance and neuroregulatory proteins. The KS proteoglycan microtubule associated protein-1B (MAP1B) stabilizes actin and tubulin cytoskeletal development during neuritogenesis. A second 12 span transmembrane synaptic vesicle associated KS proteoglycan (SV2) provides a smart gel storage matrix for the storage of neurotransmitters. MAP1B and SV2 have prominent roles to play in neuroregulation. Aggrecan and phosphacan have roles in perineuronal net formation and in neuroregulation. A greater understanding of the biology of KS may be insightful as to how neural repair might be improved.
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Affiliation(s)
- James Melrose
- Raymond Purves Bone and Joint Research Laboratories, Kolling Institute of Medical Research, Royal North Shore Hospital and University of Sydney, St. Leonards, NSW, 2065, Australia.,Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.,Sydney Medical School, Northern, Sydney University, Royal North Shore Hospital, St. Leonards, NSW, 2065, Australia.,Faculty of Medicine and Health, University of Sydney, Royal North Shore Hospital, St. Leonards, NSW, 2065, Australia
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36
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Abstract
A new mechanism that contributes to control of hearing sensitivity is described here. We show that an accessory structure in the hearing organ, the tectorial membrane, affects the function of inner ear sensory cells by storing calcium ions. When the calcium store is depleted, by brief exposure to rock concert-level sounds or by the introduction of calcium chelators, the sound-evoked responses of the sensory cells decrease. Upon restoration of tectorial membrane calcium, sensory cell function returns. This previously unknown mechanism contributes to explaining the temporary numbness in the ear that follows from listening to sounds that are too loud, a phenomenon that most people experience at some point in their lives. When sound stimulates the stereocilia on the sensory cells in the hearing organ, Ca2+ ions flow through mechanically gated ion channels. This Ca2+ influx is thought to be important for ensuring that the mechanically gated channels operate within their most sensitive response region, setting the fraction of channels open at rest, and possibly for the continued maintenance of stereocilia. Since the extracellular Ca2+ concentration will affect the amount of Ca2+ entering during stimulation, it is important to determine the level of the ion close to the sensory cells. Using fluorescence imaging and fluorescence correlation spectroscopy, we measured the Ca2+ concentration near guinea pig stereocilia in situ. Surprisingly, we found that an acellular accessory structure close to the stereocilia, the tectorial membrane, had much higher Ca2+ than the surrounding fluid. Loud sounds depleted Ca2+ from the tectorial membrane, and Ca2+ manipulations had large effects on hair cell function. Hence, the tectorial membrane contributes to control of hearing sensitivity by influencing the ionic environment around the stereocilia.
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37
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Spontaneous Otoacoustic Emissions in TectaY1870C/+ Mice Reflect Changes in Cochlear Amplification and How It Is Controlled by the Tectorial Membrane. eNeuro 2018; 5:eN-NWR-0314-18. [PMID: 30627650 PMCID: PMC6325554 DOI: 10.1523/eneuro.0314-18.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/21/2018] [Accepted: 11/26/2018] [Indexed: 12/26/2022] Open
Abstract
Spontaneous otoacoustic emissions (SOAEs) recorded from the ear canal in the absence of sound reflect cochlear amplification, an outer hair cell (OHC) process required for the extraordinary sensitivity and frequency selectivity of mammalian hearing. Although wild-type mice rarely emit, those with mutations that influence the tectorial membrane (TM) show an incidence of SOAEs similar to that in humans. In this report, we characterized mice with a missense mutation in Tecta, a gene required for the formation of the striated-sheet matrix within the core of the TM. Mice heterozygous for the Y1870C mutation (TectaY1870C/+) are prolific emitters, despite a moderate hearing loss. Additionally, Kimura’s membrane, into which the OHC stereocilia insert, separates from the main body of the TM, except at apical cochlear locations. Multimodal SOAEs are also observed in TectaY1870C/+ mice where energy is present at frequencies that are integer multiples of a lower-frequency SOAE (the primary). Second-harmonic SOAEs, at twice the frequency of a lower-frequency primary, are the most frequently observed. These secondary SOAEs are found in spatial regions where stimulus-evoked OAEs are small or in the noise floor. Introduction of high-level suppressors just above the primary SOAE frequency reduce or eliminate both primary and second-harmonic SOAEs. In contrast, second-harmonic SOAEs are not affected by suppressors, either above or below the second-harmonic SOAE frequency, even when they are much larger in amplitude. Hence, second-harmonic SOAEs do not appear to be spatially separated from their primaries, a finding that has implications for cochlear mechanics and the consequences of changes to TM structure.
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Dias AMM, Lezirovitz K, Nicastro FS, Mendes BCA, Mingroni-Netto RC. Further evidence for loss-of-function mutations in the CEACAM16 gene causing nonsyndromic autosomal recessive hearing loss in humans. J Hum Genet 2018; 64:257-260. [PMID: 30514912 DOI: 10.1038/s10038-018-0546-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/13/2018] [Accepted: 11/14/2018] [Indexed: 01/25/2023]
Abstract
Mutations in the CEACAM6 gene were first described as causing autosomal dominant nonsyndromic hearing loss, but two splice-altering variants have been recently described as causing autosomal recessive nonsyndromic hearing loss. We describe the novel and extremely rare loss-of-function variant c.436 C > T/p.(Arg146Ter) in the CEACAM16 gene segregating with post-lingual progressive autosomal recessive hearing loss. This variant is predicted to significantly reduce the size of the wild type protein. Our results give additional support that loss-of-function variants in CEACAM16 cause autosomal recessive hearing loss in humans.
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Affiliation(s)
- Alex Marcel Moreira Dias
- Centro de Pesquisas sobre o Genoma Humano e Células-Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Karina Lezirovitz
- Centro de Pesquisas sobre o Genoma Humano e Células-Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.,Laboratório de Otorrinolaringologia/LIM32 - Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Fernanda Stávale Nicastro
- Divisão de Educação e Reabilitação dos Distúrbios da Comunicação da Pontifícia Universidade Católica de São Paulo, São Paulo, Brazil
| | - Beatriz C A Mendes
- Divisão de Educação e Reabilitação dos Distúrbios da Comunicação da Pontifícia Universidade Católica de São Paulo, São Paulo, Brazil
| | - Regina Célia Mingroni-Netto
- Centro de Pesquisas sobre o Genoma Humano e Células-Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
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