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Yeo XY, Kwon S, Rinai KR, Lee S, Jung S, Park R. A Consolidated Understanding of the Contribution of Redox Dysregulation in the Development of Hearing Impairment. Antioxidants (Basel) 2024; 13:598. [PMID: 38790703 PMCID: PMC11118506 DOI: 10.3390/antiox13050598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/26/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
The etiology of hearing impairment is multifactorial, with contributions from both genetic and environmental factors. Although genetic studies have yielded valuable insights into the development and function of the auditory system, the contribution of gene products and their interaction with alternate environmental factors for the maintenance and development of auditory function requires further elaboration. In this review, we provide an overview of the current knowledge on the role of redox dysregulation as the converging factor between genetic and environmental factor-dependent development of hearing loss, with a focus on understanding the interaction of oxidative stress with the physical components of the peripheral auditory system in auditory disfunction. The potential involvement of molecular factors linked to auditory function in driving redox imbalance is an important promoter of the development of hearing loss over time.
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Affiliation(s)
- Xin Yi Yeo
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Soohyun Kwon
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
- Department of BioNanotechnology, Gachon University, Seongnam 13120, Republic of Korea
| | - Kimberley R. Rinai
- Department of Life Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Sungsu Lee
- Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Hospital and Medical School, Gwangju 61469, Republic of Korea;
| | - Sangyong Jung
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Raekil Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 61005, Republic of Korea
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Pressé MT, Malgrange B, Delacroix L. The cochlear matrisome: Importance in hearing and deafness. Matrix Biol 2024; 125:40-58. [PMID: 38070832 DOI: 10.1016/j.matbio.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/20/2023] [Accepted: 12/06/2023] [Indexed: 02/12/2024]
Abstract
The extracellular matrix (ECM) consists in a complex meshwork of collagens, glycoproteins, and proteoglycans, which serves a scaffolding function and provides viscoelastic properties to the tissues. ECM acts as a biomechanical support, and actively participates in cell signaling to induce tissular changes in response to environmental forces and soluble cues. Given the remarkable complexity of the inner ear architecture, its exquisite structure-function relationship, and the importance of vibration-induced stimulation of its sensory cells, ECM is instrumental to hearing. Many factors of the matrisome are involved in cochlea development, function and maintenance, as evidenced by the variety of ECM proteins associated with hereditary deafness. This review describes the structural and functional ECM components in the auditory organ and how they are modulated over time and following injury.
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Affiliation(s)
- Mary T Pressé
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, 15 avenue Hippocrate - CHU - B36 (1st floor), Liège B-4000, Belgium
| | - Brigitte Malgrange
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, 15 avenue Hippocrate - CHU - B36 (1st floor), Liège B-4000, Belgium
| | - Laurence Delacroix
- Developmental Neurobiology Unit, GIGA-Neurosciences, University of Liège, 15 avenue Hippocrate - CHU - B36 (1st floor), Liège B-4000, Belgium.
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3
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Genetic Hearing Loss Affects Cochlear Processing. Genes (Basel) 2022; 13:genes13111923. [DOI: 10.3390/genes13111923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/12/2022] [Accepted: 10/20/2022] [Indexed: 11/04/2022] Open
Abstract
The relationship between speech recognition and hereditary hearing loss is not straightforward. Underlying genetic defects might determine an impaired cochlear processing of sound. We obtained data from nine groups of patients with a specific type of genetic hearing loss. For each group, the affected cochlear site-of-lesion was determined based on previously published animal studies. Retrospectively obtained speech recognition scores in noise were related to several aspects of supra-threshold cochlear processing as assessed by psychophysical measurements. The differences in speech perception in noise between these patient groups could be explained by these factors and partially by the hypothesized affected structure of the cochlea, suggesting that speech recognition in noise was associated with a genetics-related malfunctioning of the cochlea. In particular, regression models indicate that loudness growth and spectral resolution best describe the cochlear distortions and are thus a good biomarker for speech understanding in noise.
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Mansour A, Sellon JB, Filizzola D, Ghaffari R, Cheatham MA, Freeman DM. Age-related degradation of tectorial membrane dynamics with loss of CEACAM16. Biophys J 2021; 120:4777-4785. [PMID: 34555361 PMCID: PMC8595744 DOI: 10.1016/j.bpj.2021.09.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/01/2021] [Accepted: 09/16/2021] [Indexed: 11/29/2022] Open
Abstract
Studies of genetic disorders of sensorineural hearing loss have been instrumental in delineating mechanisms that underlie the remarkable sensitivity and selectivity that are hallmarks of mammalian hearing. For example, genetic modifications of TECTA and TECTB, which are principal proteins that comprise the tectorial membrane (TM), have been shown to alter auditory thresholds and frequency tuning in ways that can be understood in terms of changes in the mechanical properties of the TM. Here, we investigate effects of genetic modification targeting CEACAM16, a third important TM protein. Loss of CEACAM16 has been recently shown to lead to progressive reductions in sensitivity. Whereas age-related hearing losses have previously been linked to changes in sensory receptor cells, the role of the TM in progressive hearing loss is largely unknown. Here, we show that TM stiffness and viscosity are significantly reduced in adult mice that lack functional CEACAM16 relative to age-matched wild-type controls. By contrast, these same mechanical properties of TMs from juvenile mice that lack functional CEACAM16 are more similar to those of wild-type mice. Thus, changes in hearing phenotype align with changes in TM material properties and can be understood in terms of the same TM wave properties that were previously used to characterize modifications of TECTA and TECTB. These results demonstrate that CEACAM16 is essential for maintaining TM mechanical and wave properties, which in turn are necessary for sustaining the remarkable sensitivity and selectivity of mammalian hearing with increasing age.
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Affiliation(s)
- Amer Mansour
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Jonathan B Sellon
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Daniel Filizzola
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Roozbeh Ghaffari
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Mary Ann Cheatham
- Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Knowles Hearing Center, Northwestern University, Evanston, Illinois
| | - Dennis M Freeman
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts.
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5
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Lemons C, Sellon JB, Boatti E, Filizzola D, Freeman DM, Meaud J. Anisotropic Material Properties of Wild-Type and Tectb -/- Tectorial Membranes. Biophys J 2019; 116:573-585. [PMID: 30665694 DOI: 10.1016/j.bpj.2018.12.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/28/2018] [Accepted: 12/28/2018] [Indexed: 10/27/2022] Open
Abstract
The tectorial membrane (TM) is an extracellular matrix that is directly coupled with the mechanoelectrical receptors responsible for sensory transduction and amplification. As such, the TM is often hypothesized to play a key role in the remarkable sensory abilities of the mammalian cochlea. Genetic studies targeting TM proteins have shown that changes in TM structure dramatically affect cochlear function in mice. Precise information about the mechanical properties of the TMs of wild-type and mutant mice at audio frequencies is required to elucidate the role of the TM and to understand how these genetic mutations affect cochlear mechanics. In this study, images of isolated TM segments are used to determine both the radial and longitudinal motions of the TM in response to a harmonic radial excitation. The resulting longitudinally propagating radial displacement and highly spatially dependent longitudinal displacement are modeled using finite-element models that take into account the anisotropy and finite dimensions of TMs. An automated, least-square fitting algorithm is used to find the anisotropic material properties of wild-type and Tectb-/- mice at audio frequencies. Within the auditory frequency range, it is found that the TM is a highly viscoelastic and anisotropic structure with significantly higher stiffness in the direction of the collagen fibers. Although no decrease in the stiffness in the fiber direction is observed, the stiffness of the TM in shear and in the transverse direction is found to be significantly reduced in Tectb-/- mice. As a result, TMs of the mutant mice tend to be significantly more anisotropic within the frequency range examined in this study. The effects of the Tectb-/- mutation on the TM's anisotropic material properties may be responsible for the changes in cochlear tuning and sensitivity that have been previously reported for these mice.
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Affiliation(s)
- Charlsie Lemons
- G.W.W. School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Jonathan B Sellon
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Elisa Boatti
- G.W.W. School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Daniel Filizzola
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Dennis M Freeman
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Julien Meaud
- G.W.W. School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia.
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Splice-altering variant in COL11A1 as a cause of nonsyndromic hearing loss DFNA37. Genet Med 2018; 21:948-954. [PMID: 30245514 PMCID: PMC6431578 DOI: 10.1038/s41436-018-0285-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/16/2018] [Indexed: 02/07/2023] Open
Abstract
PURPOSE The aim of this study was to determine the genetic cause of autosomal dominant nonsyndromic hearing loss segregating in a multigenerational family. METHODS Clinical examination, genome-wide linkage analysis, and exome sequencing were carried out on the family. RESULTS Affected individuals presented with early-onset progressive mild hearing impairment with a fairly flat, gently downsloping or U-shaped audiogram configuration. Detailed clinical examination excluded any additional symptoms. Linkage analysis detected an interval on chromosome 1p21 with a logarithm of the odds (LOD) score of 8.29: designated locus DFNA37. Exome sequencing identified a novel canonical acceptor splice-site variant c.652-2A>C in the COL11A1 gene within the DFNA37 locus. Genotyping of all 48 family members confirmed segregation of this variant with the deafness phenotype in the extended family. The c.652-2A>C variant is novel, highly conserved, and confirmed in vitro to alter RNA splicing. CONCLUSION We have identified COL11A1 as the gene responsible for deafness at the DFNA37 locus. Previously, COL11A1 was solely associated with Marshall and Stickler syndromes. This study expands its phenotypic spectrum to include nonsyndromic deafness. The implications of this discovery are valuable in the clinical diagnosis, prognosis, and treatment of patients with COL11A1 pathogenic variants.
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Goodyear RJ, Richardson GP. Structure, Function, and Development of the Tectorial Membrane: An Extracellular Matrix Essential for Hearing. Curr Top Dev Biol 2018; 130:217-244. [PMID: 29853178 DOI: 10.1016/bs.ctdb.2018.02.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The tectorial membrane is an extracellular matrix that lies over the apical surface of the auditory epithelia in the inner ears of reptiles, birds, and mammals. Recent studies have shown it is composed of a small set of proteins, some of which are only produced at high levels in the ear and many of which are the products of genes that, when mutated, cause nonsyndromic forms of human hereditary deafness. Quite how the proteins of the tectorial membrane are assembled within the lumen of the inner ear to form a structure that is precisely regulated in its size and physical properties along the length of a tonotopically organized hearing organ is a question that remains to be fully answered. In this brief review we will summarize what is known thus far about the structure, protein composition, and function of the tectorial membrane in birds and mammals, describe how the tectorial membrane develops, and discuss major events that have occurred during the evolution of this extracellular matrix.
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Affiliation(s)
- Richard J Goodyear
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Guy P Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, United Kingdom.
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Vona B, Maroofian R, Mendiratta G, Croken M, Peng S, Ye X, Rezazadeh J, Bahena P, Lekszas C, Haaf T, Edelmann L, Shi L. Dual Diagnosis of Ellis-van Creveld Syndrome and Hearing Loss in a Consanguineous Family. Mol Syndromol 2017; 9:5-14. [PMID: 29456477 PMCID: PMC5803684 DOI: 10.1159/000480458] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2017] [Indexed: 11/19/2022] Open
Abstract
Multilocus analysis of rare or genetically heterogeneous diseases is a distinct advantage of next-generation sequencing (NGS) over conventional single-gene investigations. Recent studies have begun to uncover an under-recognized prevalence of dual molecular diagnoses in patients with a "blended" phenotype that is the result of 2 clinical diagnoses involving 2 separate genetic loci. This blended phenotype could be mistakenly interpreted as a novel clinical extension of a single-gene disorder. In this study, we ascertained a proband from a large consanguineous Iranian family who manifests postlingual, progressive, moderate hearing loss in addition to suspected Ellis-van Creveld syndrome phenotype. NGS with a customized skeletal dysplasia panel containing over 370 genes and subsequent bioinformatics analysis disclosed 2 homozygous mutations in EVC2 (c.2653C>T; p.Arg885*) and COL11A2 (c.966dup; p.Thr323Hisfs*19), respectively. This study highlights a dual molecular diagnosis in a patient with a blending of 2 distinct phenotypes and illustrates the advantage and importance of this staple technology to facilitate rapid and comprehensive genetic dissection of a heterogeneous phenotype. The differentiation between phenotypic expansion of a genetic disorder and a blended phenotype that is due to more than one distinct genetic aberration is essential in order to reduce the diagnostic odyssey endured by patients.
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Affiliation(s)
- Barbara Vona
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Reza Maroofian
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
| | - Geetu Mendiratta
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Matthew Croken
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Siwu Peng
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Xiaoqian Ye
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Dentistry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Jamileh Rezazadeh
- Genetic Counselling and Rehabilitation Unit, Welfare Organization, South Khorasan, Iran
| | - Paulina Bahena
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Caroline Lekszas
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University Würzburg, Würzburg, Germany
| | - Lisa Edelmann
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lisong Shi
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Mao B, Moss CF, Wilkinson GS. Age-dependent gene expression in the inner ear of big brown bats (Eptesicus fuscus). PLoS One 2017; 12:e0186667. [PMID: 29073148 PMCID: PMC5658057 DOI: 10.1371/journal.pone.0186667] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 10/05/2017] [Indexed: 12/25/2022] Open
Abstract
For echolocating bats, hearing is essential for survival. Specializations for detecting and processing high frequency sounds are apparent throughout their auditory systems. Recent studies on echolocating mammals have reported evidence of parallel evolution in some hearing-related genes in which distantly related groups of echolocating animals (bats and toothed whales), cluster together in gene trees due to apparent amino acid convergence. However, molecular adaptations can occur not only in coding sequences, but also in the regulation of gene expression. The aim of this study was to examine the expression of hearing-related genes in the inner ear of developing big brown bats, Eptesicus fuscus, during the period in which echolocation vocalizations increase dramatically in frequency. We found that seven genes were significantly upregulated in juveniles relative to adults, and that the expression of four genes through development correlated with estimated age. Compared to available data for mice, it appears that expression of some hearing genes is extended in juvenile bats. These results are consistent with a prolonged growth period required to develop larger cochlea relative to body size, a later maturation of high frequency hearing, and a greater dependence on high frequency hearing in echolocating bats.
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Affiliation(s)
- Beatrice Mao
- Department of Biology, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Cynthia F. Moss
- Department of Psychological and Brain Sciences, Zanvyl Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Gerald S. Wilkinson
- Department of Biology, College of Computer, Mathematical, and Natural Sciences, University of Maryland, College Park, Maryland, United States of America
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Teudt IU, Richter CP. Basilar membrane and tectorial membrane stiffness in the CBA/CaJ mouse. J Assoc Res Otolaryngol 2014; 15:675-94. [PMID: 24865766 PMCID: PMC4164692 DOI: 10.1007/s10162-014-0463-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 05/07/2014] [Indexed: 10/25/2022] Open
Abstract
The mouse has become an important animal model in understanding cochlear function. Structures, such as the tectorial membrane or hair cells, have been changed by gene manipulation, and the resulting effect on cochlear function has been studied. To contrast those findings, physical properties of the basilar membrane (BM) and tectorial membrane (TM) in mice without gene mutation are of great importance. Using the hemicochlea of CBA/CaJ mice, we have demonstrated that tectorial membrane (TM) and basilar membrane (BM) revealed a stiffness gradient along the cochlea. While a simple spring mass resonator predicts the change in the characteristic frequency of the BM, the spring mass model does not predict the frequency change along the TM. Plateau stiffness values of the TM were 0.6 ± 0.5, 0.2 ± 0.1, and 0.09 ± 0.09 N/m for the basal, middle, and upper turns, respectively. The BM plateau stiffness values were 3.7 ± 2.2, 1.2 ± 1.2, and 0.5 ± 0.5 N/m for the basal, middle, and upper turns, respectively. Estimations of the TM Young's modulus (in kPa) revealed 24.3 ± 25.2 for the basal turns, 5.1 ± 4.5 for the middle turns, and 1.9 ± 1.6 for the apical turns. Young's modulus determined at the BM pectinate zone was 76.8 ± 72, 23.9 ± 30.6, and 9.4 ± 6.2 kPa for the basal, middle, and apical turns, respectively. The reported stiffness values of the CBA/CaJ mouse TM and BM provide basic data for the physical properties of its organ of Corti.
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Affiliation(s)
- I. U. Teudt
- />Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Searle Building 12-561; 303 East Chicago Avenue, 60611-3008 Chicago, IL USA
- />Department of Otolaryngology—Head and Neck Surgery, University Clinic Hamburg-Eppendorf, Hamburg, Germany
- />Department of Otolaryngology—Head and Neck Surgery, Asklepios Clinic Altona, Hamburg, Germany
| | - C. P. Richter
- />Department of Otolaryngology—Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Searle Building 12-561; 303 East Chicago Avenue, 60611-3008 Chicago, IL USA
- />Department of Biomedical Engineering, Northwestern University, Evanston, IL USA
- />Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL USA
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11
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Jones GP, Lukashkina VA, Russell IJ, Elliott SJ, Lukashkin AN. Frequency-dependent properties of the tectorial membrane facilitate energy transmission and amplification in the cochlea. Biophys J 2013; 104:1357-66. [PMID: 23528095 DOI: 10.1016/j.bpj.2013.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/29/2013] [Accepted: 02/07/2013] [Indexed: 10/27/2022] Open
Abstract
The remarkable sensitivity, frequency selectivity, and dynamic range of the mammalian cochlea relies on longitudinal transmission of minuscule amounts of energy as passive, pressure-driven, basilar membrane (BM) traveling waves. These waves are actively amplified at frequency-specific locations by a mechanism that involves interaction between the BM and another extracellular matrix, the tectorial membrane (TM). From mechanical measurements of isolated segments of the TM, we made the important new (to our knowledge) discovery that the stiffness of the TM is reduced when it is mechanically stimulated at physiologically relevant magnitudes and at frequencies below their frequency place in the cochlea. The reduction in stiffness functionally uncouples the TM from the organ of Corti, thereby minimizing energy losses during passive traveling-wave propagation. Stiffening and decreased viscosity of the TM at high stimulus frequencies can potentially facilitate active amplification, especially in the high-frequency, basal turn, where energy loss due to internal friction within the TM is less than in the apex. This prediction is confirmed by neural recordings from several frequency regions of the cochlea.
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Affiliation(s)
- G P Jones
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
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12
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Hearing impairment in Stickler syndrome: a systematic review. Orphanet J Rare Dis 2012; 7:84. [PMID: 23110709 PMCID: PMC3551705 DOI: 10.1186/1750-1172-7-84] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 10/22/2012] [Indexed: 11/29/2022] Open
Abstract
Background Stickler syndrome is a connective tissue disorder characterized by ocular, skeletal, orofacial and auditory defects. It is caused by mutations in different collagen genes, namely COL2A1, COL11A1 and COL11A2 (autosomal dominant inheritance), and COL9A1 and COL9A2 (autosomal recessive inheritance). The auditory phenotype in Stickler syndrome is inconsistently reported. Therefore we performed a systematic review of the literature to give an up-to-date overview of hearing loss in Stickler syndrome, and correlated it with the genotype. Methods English-language literature was reviewed through searches of PubMed and Web of Science, in order to find relevant articles describing auditory features in Stickler patients, along with genotype. Prevalences of hearing loss are calculated and correlated with the different affected genes and type of mutation. Results 313 patients (102 families) individually described in 46 articles were included. Hearing loss was found in 62.9%, mostly mild to moderate when reported. Hearing impairment was predominantly sensorineural (67.8%). Conductive (14.1%) and mixed (18.1%) hearing loss was primarily found in young patients or patients with a palatal defect. Overall, mutations in COL11A1 (82.5%) and COL11A2 (94.1%) seem to be more frequently associated with hearing impairment than mutations in COL2A1 (52.2%). Conclusions Hearing impairment in patients with Stickler syndrome is common. Sensorineural hearing loss predominates, but also conductive hearing loss, especially in children and patients with a palatal defect, may occur. The distinct disease-causing collagen genes are associated with a different prevalence of hearing impairment, but still large phenotypic variation exists. Regular auditory follow-up is strongly advised, particularly because many Stickler patients are visually impaired.
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Gavara N, Manoussaki D, Chadwick RS. Auditory mechanics of the tectorial membrane and the cochlear spiral. Curr Opin Otolaryngol Head Neck Surg 2011; 19:382-7. [PMID: 21785353 PMCID: PMC3327783 DOI: 10.1097/moo.0b013e32834a5bc9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW This review is timely and relevant because new experimental and theoretical findings suggest that cochlear mechanics from the nanoscale to the macroscale are affected by the mechanical properties of the tectorial membrane and the cochlea's spiral shape. RECENT FINDINGS Main tectorial membrane themes addressed in this review are composition and morphology, nanoscale mechanical interactions with the outer hair cell bundle, macroscale longitudinal coupling, fluid interaction with inner hair cell bundles, and macroscale dynamics and waves. Main cochlear spiral themes are macroscale, low-frequency energy focusing and microscale organ of Corti shear gain. SUMMARY Recent experimental and theoretical findings reveal exquisite sensitivity of cochlear mechanical performance to tectorial membrane structural organization, mechanics, and its positioning with respect to hair bundles. The cochlear spiral geometry is a major determinant of low-frequency hearing. These findings suggest a number of important research directions.
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Affiliation(s)
- Núria Gavara
- Auditory Mechanics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA
| | - Daphne Manoussaki
- Department of Sciences, Technical University of Crete, Hania, Greece
| | - Richard S. Chadwick
- Auditory Mechanics Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA
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Liu CC, Gao SS, Yuan T, Steele C, Puria S, Oghalai JS. Biophysical mechanisms underlying outer hair cell loss associated with a shortened tectorial membrane. J Assoc Res Otolaryngol 2011; 12:577-94. [PMID: 21567249 PMCID: PMC3173552 DOI: 10.1007/s10162-011-0269-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Accepted: 04/17/2011] [Indexed: 01/09/2023] Open
Abstract
The tectorial membrane (TM) connects to the stereociliary bundles of outer hair cells (OHCs). Humans with an autosomal dominant C1509G mutation in alpha-tectorin, a protein constituent of the TM, are born with a partial hearing loss that worsens over time. The Tecta(C1509/+) transgenic mouse with the same point mutation has partial hearing loss secondary to a shortened TM that only contacts the first row of OHCs. As well, Tecta(C1509G/+) mice have increased expression of the OHC electromotility protein, prestin. We sought to determine whether these changes impact OHC survival. Distortion product otoacoustic emission thresholds in a quiet environment did not change to 6 months of age. However, noise exposure produced acute threshold shifts that fully recovered in Tecta (+/+) mice but only partially recovered in Tecta(C1509G/+) mice. While Tecta(+/+) mice lost OHCs primarily at the base and within all three rows, Tecta(C1509G/+) mice lost most of their OHCs in a more apical region of the cochlea and nearly completely within the first row. In order to estimate the impact of a shorter TM on the forces faced by the stereocilia within the first OHC row, both the wild type and the heterozygous conditions were simulated in a computational model. These analyses predicted that the shear force on the stereocilia is ~50% higher in the heterozygous condition. We then measured electrically induced movements of the reticular lamina in situ and found that while they decreased to the noise floor in prestin null mice, they were increased by 4.58 dB in Tecta(C1509G/+) mice compared to Tecta(+/+) mice. The increased movements were associated with a fourfold increase in OHC death as measured by vital dye staining. Together, these findings indicate that uncoupling the TM from some OHCs leads to partial hearing loss and places the remaining coupled OHCs at higher risk. Both the mechanics of the malformed TM and the increased prestin-related movements of the organ of Corti contribute to this higher risk profile.
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Affiliation(s)
- Christopher C. Liu
- The Bobby R. Alford Department of Otolaryngology–Head and Neck Surgery, Baylor College of Medicine, Houston, TX 77030 USA
| | - Simon S. Gao
- Department of Bioengineering, Rice University, Houston, TX 77005 USA
| | - Tao Yuan
- The Bobby R. Alford Department of Otolaryngology–Head and Neck Surgery, Baylor College of Medicine, Houston, TX 77030 USA
| | - Charles Steele
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94304-5739 USA
| | - Sunil Puria
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94304-5739 USA
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305-5739 USA
| | - John S. Oghalai
- Department of Bioengineering, Rice University, Houston, TX 77005 USA
- Department of Otolaryngology–Head and Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305-5739 USA
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Gueta R, Levitt J, Xia A, Katz O, Oghalai JS, Rousso I. Structural and mechanical analysis of tectorial membrane Tecta mutants. Biophys J 2011; 100:2530-8. [PMID: 21575588 DOI: 10.1016/j.bpj.2011.04.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Revised: 03/15/2011] [Accepted: 04/04/2011] [Indexed: 11/18/2022] Open
Abstract
The tectorial membrane (TM) is an extracellular matrix of the cochlea whose prominent role in hearing has been demonstrated through mutation studies. The C1509G mutation of the Tecta gene, which encodes for the α-tectorin protein, leads to hearing loss. The heterozygote TM only attaches to the first row of outer hair cells (OHCs), and the homozygote TM does not attach to any OHCs. Here we measured the morphology and mechanical properties of wild-type, heterozygous, and homozygous Tecta TMs. Morphological analyses conducted with second- and third-harmonic imaging, scanning electron microscopy, and immunolabeling revealed marked changes in the collagen architecture and stereocilin-labeling patterns of the mutant TMs. The mechanical properties of the mutant TM were measured by force spectroscopy. Whereas the axial Young's modulus of the low-frequency (apical) region of Tecta mutant TM samples was similar to that of wild-type TMs, it significantly decreased in the basal region to a value approaching that found at the apex. Modeling simulations suggest that a reduced TM Young's modulus is likely to reduce OHC stereociliary deflection. These findings argue that the heterozygote C1509G mutation results in a lack of attachment of the TM to the OHCs, which in turn reduces both the overall number of OHCs that are involved in mechanotransduction and the degree of mechanotransduction exhibited by the OHCs that remain attached to the TM.
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Affiliation(s)
- Rachel Gueta
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
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16
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Masaki K, Ghaffari R, Gu JW, Richardson GP, Freeman DM, Aranyosi AJ. Tectorial membrane material properties in Tecta(Y)(1870C/+) heterozygous mice. Biophys J 2011; 99:3274-81. [PMID: 21081075 DOI: 10.1016/j.bpj.2010.09.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2010] [Revised: 09/01/2010] [Accepted: 09/20/2010] [Indexed: 11/17/2022] Open
Abstract
The solid component of the tectorial membrane (TM) is a porous matrix made up of the radial collagen fibers and the striated sheet matrix. The striated sheet matrix is believed to contribute to shear impedance in both the radial and longitudinal directions, but the molecular mechanisms involved have not been determined. A missense mutation in Tecta, a gene that encodes for the α-tectorin protein in the striated sheet matrix, causes a 60-dB threshold shift in mice with relatively little reduction in outer hair cell amplification. Here, we show that this threshold shift is coupled to changes in shear impedance, response to osmotic pressure, and concentration of fixed charge of the TM. In Tecta(Y)(1870C/+) mice, the tectorin content of the TM was reduced, as was the content of glycoconjugates reacting with the lectin wheat germ agglutinin. Charge measurements showed a decrease in fixed charge concentration from -6.4±1.4 mmol/L in wild-types to -2.1±0.7 mmol/L in Tecta(Y)(1870C/+) TMs. TMs from Tecta(Y)(1870C/+) mice showed little volume change in response to osmotic pressure compared to those of wild-type mice. The magnitude of both radial and longitudinal TM shear impedance was reduced by 10±1.6 dB in Tecta(Y)(1870C/+) mice. However, the phase of shear impedance was unchanged. These changes are consistent with an increase in the porosity of the TM and a corresponding decrease of the solid fraction. Mechanisms by which these changes can affect the coupling between outer and inner hair cells are discussed.
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Affiliation(s)
- Kinuko Masaki
- Massachusetts Institute of Technology, Cambridge, MA, USA
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Tokgöz-Yilmaz S, Şahli S, Fitoz S, Sennaroğlu G, Tekin M. Audiological findings in otospondylomegaepiphyseal dysplasia (OSMED) associated with a novel mutation in COL11A2. Int J Pediatr Otorhinolaryngol 2011; 75:433-7. [PMID: 21208667 PMCID: PMC3040286 DOI: 10.1016/j.ijporl.2010.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/05/2010] [Accepted: 12/06/2010] [Indexed: 01/22/2023]
Abstract
The aim of the study was to assess the audiological findings of a 4-year-old child with a homozygous COL11A2 mutation and to point out the role of continuous follow-ups in children with craniofacial syndromes after the newborn hearing screening. A 4-year-old boy with otospondylomegaepiphyseal dysplasia (OSMED) was followed up after birth for hearing loss. Transient Otoacoustic Emissions (TEOAEs), Distortion Product Otoacoustic Emissions (DPOAEs), Automated and Clinical Auditory Brainstem Response (AABR and ABR) measurements, Visual Reinforcement Audiometry, immitansmetric measurements and hearing threshold measurements were performed for audiological evaluation. The patient developed sensorineural hearing loss at 11 months of age while his hearing was normal at birth. Because of auditory-verbal training with hearing aids started at 20 months of age, he now has normal verbal communication with his peers. This study clearly demonstrates that hearing loss develops in infancy in patients with OSMED and underscores the importance of continued hearing screening beyond newborn period for early intervention of hearing impairment and communication problems.
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Affiliation(s)
- Suna Tokgöz-Yilmaz
- Division of Pediatric Genetics, Ankara University School of Medicine, Ankara, Turkey,Department of Audiology, Ankara University Vocational School of Health, Ankara, Turkey
| | - Sanem Şahli
- Department of Otorhinolaryngology, Hacettepe University Faculty of Medicine, Audiology and Speech Pathology Section, Ankara, Turkey
| | - Suat Fitoz
- Department of Radiology, Ankara University School of Medicine, Ankara, Turkey
| | - Gonca Sennaroğlu
- Department of Otorhinolaryngology, Hacettepe University Faculty of Medicine, Audiology and Speech Pathology Section, Ankara, Turkey
| | - Mustafa Tekin
- Division of Pediatric Genetics, Ankara University School of Medicine, Ankara, Turkey,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, USA,Correspondence to: Mustafa Tekin, M.D., 1501 NW 10th Avenue, BRB-610 (M-860), Miami, FL 33136, Ph: 305-243-2381, Fax: 305-243-2703,
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Bergevin C, Velenovsky DS, Bonine KE. Tectorial membrane morphological variation: effects upon stimulus frequency otoacoustic emissions. Biophys J 2010; 99:1064-72. [PMID: 20712989 DOI: 10.1016/j.bpj.2010.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 05/21/2010] [Accepted: 06/04/2010] [Indexed: 10/19/2022] Open
Abstract
The tectorial membrane (TM) is widely believed to play an important role in determining the ear's ability to detect and resolve incoming acoustic information. While it is still unclear precisely what that role is, the TM has been hypothesized to help overcome viscous forces and thereby sharpen mechanical tuning of the sensory cells. Lizards present a unique opportunity to further study the role of the TM given the diverse inner-ear morphological differences across species. Furthermore, stimulus-frequency otoacoustic emissions (SFOAEs), sounds emitted by the ear in response to a tone, noninvasively probe the frequency selectivity of the ear. We report estimates of auditory tuning derived from SFOAEs for 12 different species of lizards with widely varying TM morphology. Despite gross anatomical differences across the species examined herein, low-level SFOAEs were readily measurable in all ears tested, even in non-TM species whose basilar papilla contained as few as 50-60 hair cells. Our measurements generally support theoretical predictions: longer delays/sharper tuning features are found in species with a TM relative to those without. However, SFOAEs from at least one non-TM species (Anolis) with long delays suggest there are likely additional micromechanical factors at play that can directly affect tuning. Additionally, in the one species examined with a continuous TM (Aspidoscelis) where cell-to-cell coupling is presumably relatively stronger, delays were intermediate. This observation appears consistent with recent reports that suggest the TM may play a more complex macromechanical role in the mammalian cochlea via longitudinal energy distribution (and thereby affect tuning). Although significant differences exist between reptilian and mammalian auditory biophysics, understanding lizard OAE generation mechanisms yields significant insight into fundamental principles at work in all vertebrate ears.
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