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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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2
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Verdoodt D, Van Camp G, Ponsaerts P, Van Rompaey V. On the pathophysiology of DFNA9: Effect of pathogenic variants in the COCH gene on inner ear functioning in human and transgenic mice. Hear Res 2020; 401:108162. [PMID: 33421658 DOI: 10.1016/j.heares.2020.108162] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 11/27/2020] [Accepted: 12/27/2020] [Indexed: 12/20/2022]
Abstract
DeaFNess Autosomal Dominant 9 (DFNA9) is a dominant hereditary non-syndromic form of progressive sensorineural hearing loss often associated with vestibular dysfunction. DFNA9 is caused by pathogenic variants in the COCH gene. This gene encodes for cochlin, a protein that is abundantly expressed in the spiral ligament and spiral limbus of the inner ear but the function of cochlin is still not fully understood. There are 22 known pathogenic variants located in different domains of the COCH gene that can cause DFNA9, all expressing slightly different phenotypes. It is believed that COCH mutations affect the intracellular trafficking of cochlin which could explain the characteristic pathology seen in temporal bones of DFNA9 patients. This pathology involves a widespread accumulation of acellular eosinophilic deposits throughout the labyrinth. To gain a better understanding of the pathology underlying DFNA9, different mouse models were developed. The objective of this review is to describe the different pathogenic variants in the COCH gene and their effect on intracellular trafficking, associated phenotypes and histopathological findings in both patients and mouse models.
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Affiliation(s)
- Dorien Verdoodt
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium; Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Belgium.
| | - Guy Van Camp
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Belgium
| | - Vincent Van Rompaey
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium; Department of Otorhinolaryngology and Head & Neck surgery, Antwerp University Hospital, Belgium
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3
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Auditory function analysis in immunodeficient STAT1 knock-out mice: Considerations for viral infection models. Neurosci Lett 2020; 740:135427. [PMID: 33069812 DOI: 10.1016/j.neulet.2020.135427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 09/20/2020] [Accepted: 10/07/2020] [Indexed: 11/24/2022]
Abstract
The STAT1 knock-out (KO) mouse is a frequently used transgenic immunodeficient strain to model human viral and bacterial diseases. The Lassa fever model was established in the STAT1 KO mice mimicking phenotypes seen in human patients including deafness in survivors. This model develops hearing loss at high prevalence and is a valuable tool to investigate viral infection-induced hearing loss. However, Lassa virus is a highly contagious and regulated agent requiring the unique logistics of the biosafety level 4 posing limitations for experimental work. Therefore, we did a detailed auditory analysis of the STAT1 KO mice to assess baseline auditory function in preparation for further auditory behavioral studies. Auditory brainstem response and distortion product otoacoustic emission tests were performed on males and females of the STAT1 KO mice and was compared to 129S6/SvEv wild type (WT) mice. The male WT mice had the best auditory performance and the female WT mice had the worst hearing performance. The male and female STAT1 KO mice had similar auditory performance to each other, which was intermediate between WT males and females. We conclude that both male and female STAT1 KO mice are suitable for studying viral infection-induced hearing loss.
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4
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Novel loss-of-function mutations in COCH cause autosomal recessive nonsyndromic hearing loss. Hum Genet 2020; 139:1565-1574. [PMID: 32562050 DOI: 10.1007/s00439-020-02197-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/12/2020] [Indexed: 12/12/2022]
Abstract
COCH is the most abundantly expressed gene in the cochlea. Unsurprisingly, mutations in COCH underly hearing loss in mice and humans. Two forms of hearing loss are linked to mutations in COCH, the well-established autosomal dominant nonsyndromic hearing loss, with or without vestibular dysfunction (DFNA9) via a gain-of-function/dominant-negative mechanism, and more recently autosomal recessive nonsyndromic hearing loss (DFNB110) via nonsense variants. Using a combination of targeted gene panels, exome sequencing, and functional studies, we identified four novel pathogenic variants (two nonsense variants, one missense, and one inframe deletion) in COCH as the cause of autosomal recessive hearing loss in a multi-ethnic cohort. To investigate whether the non-truncating variants exert their effect via a loss-of-function mechanism, we used minigene splicing assays. Our data showed both the missense and inframe deletion variants altered RNA splicing by creating an exon splicing silencer and abolishing an exon splicing enhancer, respectively. Both variants create frameshifts and are predicted to result in a null allele. This study confirms the involvement of loss-of-function mutations in COCH in autosomal recessive nonsyndromic hearing loss, expands the mutational landscape of DFNB110 to include coding variants that alter RNA splicing, and highlights the need to investigate the effect of coding variants on RNA splicing.
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Downie L, Halliday J, Burt R, Lunke S, Lynch E, Martyn M, Poulakis Z, Gaff C, Sung V, Wake M, Hunter MF, Saunders K, Rose E, Lewis S, Jarmolowicz A, Phelan D, Rehm HL, Amor DJ. Exome sequencing in infants with congenital hearing impairment: a population-based cohort study. Eur J Hum Genet 2019; 28:587-596. [PMID: 31827275 DOI: 10.1038/s41431-019-0553-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/30/2019] [Accepted: 11/07/2019] [Indexed: 12/11/2022] Open
Abstract
Congenital hearing impairment (HI) is the most common sensory impairment and can be isolated or part of a syndrome. Diagnosis through newborn hearing screening and management through early intervention, hearing aids and cochlear implantation is well established in the Australian setting; however understanding the genetic basis of congenital HI has been missing. This population-derived cohort comprised infants with moderate-profound bilateral HI born in the 2016-2017 calendar years, detected through newborn hearing screening. Participants were recruited through an integrated paediatric, otolaryngology and genetics HI clinic and offered whole exome sequencing (WES) on a HiSeq4000 or NextSeq500 (Illumina) platform with a targeted average sequencing depth of 100x and chromosome microarray on the Illumina Infinium core exome-24v1.2 platform. Of those approached, 68% (106/156) consented to participate. The rate of genetic diagnosis was 56% (59/106), significantly higher than standard of care (GJB2/6 sequencing only), 21% (22/106). There were clinical implications for the 106 participants: 36% required no further screening, 9% had tailored screening initiated, 2% were offered treatment and 4% had informed care for a complex neurodevelopmental syndrome. WES in this cohort demonstrates the range of diagnoses associated with congenital HI and confirms the genetic heterogeneity of congenital HI. The high diagnostic yield and clinical implications emphasises the need for genomic sequencing to become standard of care.
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Affiliation(s)
- Lilian Downie
- Victorian Clinical Genetics Services, Melbourne, VIC, Australia.,Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Jane Halliday
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Rachel Burt
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Sebastian Lunke
- Victorian Clinical Genetics Services, Melbourne, VIC, Australia.,Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Elly Lynch
- Victorian Clinical Genetics Services, Melbourne, VIC, Australia.,Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Melbourne Genomics Health Alliance, Melbourne, VIC, Australia
| | - Melissa Martyn
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia.,Melbourne Genomics Health Alliance, Melbourne, VIC, Australia
| | - Zeffie Poulakis
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Clara Gaff
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia.,Melbourne Genomics Health Alliance, Melbourne, VIC, Australia
| | - Valerie Sung
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Melissa Wake
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Matthew F Hunter
- Monash Health, Melbourne, VIC, Australia.,Monash University, Melbourne, VIC, Australia
| | - Kerryn Saunders
- Monash Health, Melbourne, VIC, Australia.,Monash University, Melbourne, VIC, Australia
| | - Elizabeth Rose
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Sharon Lewis
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Anna Jarmolowicz
- Victorian Clinical Genetics Services, Melbourne, VIC, Australia.,Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Dean Phelan
- Victorian Clinical Genetics Services, Melbourne, VIC, Australia.,Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Heidi L Rehm
- Massachusetts General Hospital and the Broad Institute of MIT and Harvard, Boston, MA, USA
| | | | - David J Amor
- Victorian Clinical Genetics Services, Melbourne, VIC, Australia. .,Murdoch Children's Research Institute, Melbourne, VIC, Australia. .,Royal Children's Hospital, Melbourne, VIC, Australia. .,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia.
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6
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Burton JA, Valero MD, Hackett TA, Ramachandran R. The use of nonhuman primates in studies of noise injury and treatment. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3770. [PMID: 31795680 PMCID: PMC6881191 DOI: 10.1121/1.5132709] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 05/10/2023]
Abstract
Exposure to prolonged or high intensity noise increases the risk for permanent hearing impairment. Over several decades, researchers characterized the nature of harmful noise exposures and worked to establish guidelines for effective protection. Recent laboratory studies, primarily conducted in rodent models, indicate that the auditory system may be more vulnerable to noise-induced hearing loss (NIHL) than previously thought, driving renewed inquiries into the harmful effects of noise in humans. To bridge the translational gaps between rodents and humans, nonhuman primates (NHPs) may serve as key animal models. The phylogenetic proximity of NHPs to humans underlies tremendous similarity in many features of the auditory system (genomic, anatomical, physiological, behavioral), all of which are important considerations in the assessment and treatment of NIHL. This review summarizes the literature pertaining to NHPs as models of hearing and noise-induced hearing loss, discusses factors relevant to the translation of diagnostics and therapeutics from animals to humans, and concludes with some of the practical considerations involved in conducting NHP research.
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Affiliation(s)
- Jane A Burton
- Neuroscience Graduate Program, Vanderbilt University, Nashville, Tennessee 37212, USA
| | - Michelle D Valero
- Eaton Peabody Laboratories at Massachusetts Eye and Ear, Boston, Massachusetts 02114, USA
| | - Troy A Hackett
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Ramnarayan Ramachandran
- Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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Bommakanti K, Iyer JS, Stankovic KM. Cochlear histopathology in human genetic hearing loss: State of the science and future prospects. Hear Res 2019; 382:107785. [PMID: 31493568 PMCID: PMC6778517 DOI: 10.1016/j.heares.2019.107785] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/30/2019] [Accepted: 08/15/2019] [Indexed: 12/22/2022]
Abstract
Sensorineural hearing loss (SNHL) is an extraordinarily common disability, affecting 466 million people across the globe. Half of these incidents are attributed to genetic mutations that disrupt the structure and function of the cochlea. The human cochlea's interior cannot be imaged or biopsied without damaging hearing; thus, everything known about the morphologic correlates of hereditary human deafness comes from histopathologic studies conducted in either cadaveric human temporal bone specimens or animal models of genetic deafness. The purpose of the present review is to a) summarize the findings from all published histopathologic studies conducted in human temporal bones with known SNHL-causing genetic mutations, and b) compare the reported phenotypes of human vs. mouse SNHL caused by the same genetic mutation. The fact that human temporal bone histopathologic analysis has been reported for only 22 of the nearly 200 identified deafness-causing genes suggests a great need for alternative and improved techniques for studying human hereditary deafness; in light of this, the present review concludes with a summary of promising future directions, specifically in the fields of high resolution cochlear imaging, intracochlear fluid biopsy, and gene therapy.
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Affiliation(s)
- Krishna Bommakanti
- Department of Otolaryngology, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA; University of California San Diego School of Medicine, San Diego, CA, USA
| | - Janani S Iyer
- Department of Otolaryngology, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA; Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, USA; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
| | - Konstantina M Stankovic
- Department of Otolaryngology, Harvard Medical School, Boston, MA, USA; Eaton Peabody Laboratories and Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA; Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, USA; Harvard Program in Therapeutic Science, Harvard Medical School, Boston, MA, USA.
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8
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Cleaved Cochlin Sequesters Pseudomonas aeruginosa and Activates Innate Immunity in the Inner Ear. Cell Host Microbe 2019; 25:513-525.e6. [DOI: 10.1016/j.chom.2019.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/14/2018] [Accepted: 02/05/2019] [Indexed: 02/06/2023]
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Pawlak-Osiñska K, Linkowska K, Grzybowski T. Genes important for otoneurological diagnostic purposes - current status and future prospects. ACTA ACUST UNITED AC 2018; 38:242-250. [PMID: 29984802 DOI: 10.14639/0392-100x-1692] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/12/2017] [Indexed: 11/23/2022]
Abstract
SUMMARY This review focuses on the current knowledge of the genes responsible for non-syndromic hearing loss that can be useful for otoneurological diagnostic purposes. From among a large number of genes that have been associated with non-syndromic hearing impairment, we selected several best-known genes, including the COCH gene, GJB2, GJB6 and SLC26A4, and we describe their role and effects of mutations and prevalence of mutations in various populations. Next, we focus on genes associated with tinnitus. Important areas for further research include assessment of genes potentially involved in pathophysiology of tinnitus and vertigo, which have traditionally been considered as being of otological aetiology, while advances in neuroimaging techniques have increasingly shifted studies toward neurological correlations.
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Affiliation(s)
- K Pawlak-Osiñska
- Department of Otolaryngology and Oncology Collegium Medicum in Bydgoszcz Nicolaus Copernicus University, Skłodowskiej-Curie 9, Bydgoszcz, Poland
| | - K Linkowska
- Department of Forensic Medicine Division of Molecular and Forensic Genetics Collegium Medicum in Bydgoszcz Nicolaus Copernicus University, Skłodowskiej-Curie 9, Bydgoszcz, Poland
| | - T Grzybowski
- Department of Forensic Medicine Division of Molecular and Forensic Genetics Collegium Medicum in Bydgoszcz Nicolaus Copernicus University, Skłodowskiej-Curie 9, Bydgoszcz, Poland
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Bi-allelic inactivating variants in the COCH gene cause autosomal recessive prelingual hearing impairment. Eur J Hum Genet 2018; 26:587-591. [PMID: 29449721 DOI: 10.1038/s41431-017-0066-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 01/19/2023] Open
Abstract
Pathogenic variant in COCH are a known cause of DFNA9 autosomal dominant progressive hearing loss and vestibular dysfunction with adult onset. Hitherto, only dominant nonsynonymous variants and in-frame deletions with a presumed dominant negative or gain-of-function effect have been described. Here, we describe two brothers with congenital prelingual deafness and a homozygous nonsense c.292C>T(p.Arg98*) COCH variant, suggesting a loss-of-function effect. Vestibular dysfunction starting in the first decade was observed in the older patient. The heterozygous parents and sibling have normal hearing and vestibular function, except for the mother, who shows vestibular hyporeflexia and abnormal smooth pursuit tests, most likely due to concomitant disease. This is the first report of autosomal recessive inheritance of cochlea-vestibular dysfunction caused by a pathogenic variant in the COCH gene. An earlier onset of hearing impairment and vestibular dysfunction compared to the dominant hearing loss causing COCH variants is observed.
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Parzefall T, Frohne A, Koenighofer M, Kirchnawy A, Streubel B, Schoefer C, Gstoettner W, Frei K, Lucas T. Identification of a rare COCH mutation by whole-exome sequencing : Implications for personalized therapeutic rehabilitation in an Austrian family with non-syndromic autosomal dominant late-onset hearing loss. Wien Klin Wochenschr 2017; 130:299-306. [PMID: 28733840 PMCID: PMC5966484 DOI: 10.1007/s00508-017-1230-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/26/2017] [Indexed: 12/24/2022]
Abstract
Background Non-syndromic autosomal dominant hearing impairment is characteristically postlingual in onset. Genetic diagnostics are essential for genetic counselling, disease prognosis and understanding of the molecular mechanisms of disease. To date, 36 causative genes have been identified, many in only individual families. Gene selection for genetic screening by traditional methods and genetic diagnosis in autosomal dominant patients has therefore been fraught with difficulty. Whole-exome sequencing provides a powerful tool to analyze all protein-coding genomic regions in parallel, thus allowing the comprehensive screening of all known genes and associated alterations. Methods In this study, a previously undiagnosed late-onset progressive autosomal dominant hearing loss in an Austrian family was investigated by means of whole-exome sequencing. Results were confirmed by Sanger sequencing. Results A previously described c.151C>T missense (p.Pro51Ser) mutation in the LCCL (limulus factor C, cochlin, late gestation lung protein Lgl1) domain of the cochlin gene (COCH) was identified as causative and segregated with disease in five members of the family. Molecular diagnostics led to the decision to perform cochlear implantation in an index patient who subsequently showed excellent postoperative auditory performance. The c.151C>T mutation was not found in 18 screened Austrian families with autosomal dominant hearing loss but was represented alongside other known pathogenic mutant COCH alleles in the Genome Aggregation Database (gnomAD) in European populations. A combined allele frequency of 0.000128 implies an orphan disease frequency for COCH-induced hearing loss of 1:3900 in Europe. Conclusions Exome sequencing successfully resolved the genetic diagnosis in a family suffering from autosomal dominant hearing impairment and allowed prediction of purported auditory outcome after cochlear implantation in an index patient. Personalized treatment approaches based on the molecular mechanisms of disease may become increasingly important in the future.
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Affiliation(s)
- Thomas Parzefall
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Alexandra Frohne
- Department for Cell and Developmental Biology, Orphan disease genetics group, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Martin Koenighofer
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Andreas Kirchnawy
- Department for Cell and Developmental Biology, Orphan disease genetics group, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Berthold Streubel
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Christian Schoefer
- Department for Cell and Developmental Biology, Orphan disease genetics group, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Gstoettner
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Klemens Frei
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Trevor Lucas
- Department for Cell and Developmental Biology, Orphan disease genetics group, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
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12
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Massively Parallel Sequencing of a Chinese Family with DFNA9 Identified a Novel Missense Mutation in the LCCL Domain of COCH. Neural Plast 2016; 2016:5310192. [PMID: 28116169 PMCID: PMC5223038 DOI: 10.1155/2016/5310192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/16/2016] [Accepted: 11/23/2016] [Indexed: 11/25/2022] Open
Abstract
DFNA9 is a late-onset, progressive, autosomal dominantly inherited sensorineural hearing loss with vestibular dysfunction, which is caused by mutations in the COCH (coagulation factor C homology) gene. In this study, we investigated a Chinese family segregating autosomal dominant nonsyndromic sensorineural hearing loss. We identified a missense mutation c.T275A p.V92D in the LCCL domain of COCH cosegregating with the disease and absent in 100 normal hearing controls. This mutation leads to substitution of the hydrophobic valine to an acidic amino acid aspartic acid. Our data enriched the mutation spectrum of DFNA9 and implied the importance for mutation screening of COCH in age related hearing loss with vestibular dysfunctions.
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13
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Burgess BJ, O'Malley JT, Kamakura T, Kristiansen K, Robertson NG, Morton CC, Nadol JB. Histopathology of the Human Inner Ear in the p.L114P COCH Mutation (DFNA9). Audiol Neurootol 2016; 21:88-97. [PMID: 27023102 DOI: 10.1159/000443822] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/04/2016] [Indexed: 01/05/2023] Open
Abstract
The histopathology of the inner ear in a patient with hearing loss caused by the p.L114P COCH mutation and its correlation with the clinical phenotype are presented. To date, 23 COCH mutations causative of DFNA9 autosomal dominant sensorineural hearing loss and vestibular disorder have been reported, and the histopathology of the human inner ear has been described in 4 of these. The p.L114P COCH mutation was first described in a Korean family. We have identified the same mutation in a family of non-Asian ancestry in the USA, and the temporal bone histopathology and clinical findings are presented herein. The histopathology found in the inner ear was similar to that shown in the 4 other COCH mutations and included degeneration of the spiral ligament with deposition of an eosinophilic acellular material, which was also found in the distal osseous spiral lamina, at the base of the spiral limbus, and in mesenchymal tissue at the base of the vestibular neuroepithelium. This is the first description of human otopathology of the COCH p.L114P mutation. In addition, it is the only case with otopathology characterization in an individual with any COCH mutation and residual hearing, thus allowing assessment of primary histopathological events in DFNA9, before progression to more profound hearing loss. A quantitative cytologic analysis of atrophy in this specimen and immunostaining using anti-neurofilament and anti-myelin protein zero antibodies confirmed that the principal histopathologic correlate of hearing loss was degeneration of the dendritic fibers of spiral ganglion cells in the osseous spiral lamina. The implications for cochlear implantation in this disorder are discussed.
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Affiliation(s)
- Barbara J Burgess
- Human Otopathology Laboratory, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Mass., USA
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14
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Hosoya M, Fujioka M, Ogawa K, Okano H. Distinct Expression Patterns Of Causative Genes Responsible For Hereditary Progressive Hearing Loss In Non-Human Primate Cochlea. Sci Rep 2016; 6:22250. [PMID: 26915689 PMCID: PMC4768099 DOI: 10.1038/srep22250] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 02/10/2016] [Indexed: 12/18/2022] Open
Abstract
Hearing impairment is the most frequent sensory deficit in humans. Deafness genes, which harbor pathogenic mutations that have been identified in families with hereditary hearing loss, are commonly expressed in the auditory end organ or the cochlea and may contribute to normal hearing function, yet some of the mouse models carrying these mutations fail to recapitulate the hearing loss phenotype. In this study, we find that distinct expression patterns of those deafness genes in the cochlea of a non-human primate, the common marmoset (Callithrix jacchus). We examined 20 genes whose expression in the cochlea has already been reported. The deafness genes GJB3, CRYM, GRHL2, DFNA5, and ATP6B1 were expressed in marmoset cochleae in patterns different from those in mouse cochleae. Of note, all those genes are causative for progressive hearing loss in humans, but not in mice. The other tested genes, including the deafness gene COCH, in which mutation recapitulates deafness in mice, were expressed in a similar manner in both species. The result suggests that the discrepancy in the expression between rodents and primates may account for the phenotypic difference. This limitation of the rodent models can be bypassed by using non-human primate models such as the marmoset.
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Affiliation(s)
- Makoto Hosoya
- Keio University School of Medicine, Department of Otorhinolaryngology, Head and Neck Surgery, 35 Shinanomachi Shinjyuku-ku Tokyo, 160-8582, Japan
| | - Masato Fujioka
- Keio University School of Medicine, Department of Otorhinolaryngology, Head and Neck Surgery, 35 Shinanomachi Shinjyuku-ku Tokyo, 160-8582, Japan
| | - Kaoru Ogawa
- Keio University School of Medicine, Department of Otorhinolaryngology, Head and Neck Surgery, 35 Shinanomachi Shinjyuku-ku Tokyo, 160-8582, Japan
| | - Hideyuki Okano
- Keio University School of Medicine, Department of Physiology, 35 Shinanomachi Shinjyuku-ku Tokyo, 160-8582, Japan
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Masuda M, Mutai H, Arimoto Y, Nakano A, Matsunaga T. A novel frameshift variant of COCH supports the hypothesis that haploinsufficiency is not a cause of autosomal dominant nonsyndromic deafness 9. Biochem Biophys Res Commun 2015; 469:270-4. [PMID: 26631968 DOI: 10.1016/j.bbrc.2015.11.106] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 11/23/2015] [Indexed: 11/25/2022]
Abstract
COCH (coagulation factor C homology) encodes cochlin, and certain mutations of COCH cause autosomal dominant nonsyndromic deafness 9 (DFNA9). Hearing loss due to COCH mutation begins in adulthood, and 17 missense mutations and two in-frame mutations have been reported. Studies with animal and cellular models have suggested that the underlying biological mechanism of DFNA9 is the dominant-negative effect of mutated COCH and not haploinsufficiency. However, no human cases of DFNA9 that support this hypothesis have been reported. The proband of the present case was an 18-year-old male with congenital or infantile hearing loss. Targeted next-generation sequencing analysis detected a heterozygous novel frameshift mutation of COCH (c.146dupT, p.C50LfsX8) in the proband, whose hearing loss began earlier than what is typical for DFNA9. His mother also carried the mutation but had normal hearing. Consequently, the mutation was not considered to be the cause of the proband's hearing loss. This family is the first case of a truncating COCH variant and supports the hypothesis that COCH haploinsufficiency is not the cause of hearing loss in humans.
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Affiliation(s)
- Masatsugu Masuda
- Laboratory of Auditory Disorders, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka Meguro-ku, Tokyo 152-8902, Japan; Department of Otolaryngology, School of Medicine, Kyorin University, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611, Japan.
| | - Hideki Mutai
- Laboratory of Auditory Disorders, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka Meguro-ku, Tokyo 152-8902, Japan.
| | - Yukiko Arimoto
- Department of Otolaryngology, Chiba Children's Hospital, 579-1 Hetacho, Midori-ku, Chiba-shi, Chiba 266-0007, Japan.
| | - Atsuko Nakano
- Department of Otolaryngology, Chiba Children's Hospital, 579-1 Hetacho, Midori-ku, Chiba-shi, Chiba 266-0007, Japan.
| | - Tatsuo Matsunaga
- Laboratory of Auditory Disorders, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka Meguro-ku, Tokyo 152-8902, Japan; Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka Meguro-ku, Tokyo 152-8902, Japan.
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Bae SH, Robertson NG, Cho HJ, Morton CC, Jung DJ, Baek JI, Choi SY, Lee J, Lee KY, Kim UK. Identification of pathogenic mechanisms of COCH mutations, abolished cochlin secretion, and intracellular aggregate formation: genotype-phenotype correlations in DFNA9 deafness and vestibular disorder. Hum Mutat 2015; 35:1506-1513. [PMID: 25230692 DOI: 10.1002/humu.22701] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 09/08/2014] [Indexed: 11/06/2022]
Abstract
Mutations in COCH (coagulation factor C homology) cause autosomal-dominant nonsyndromic hearing loss with variable degrees of clinical onset and vestibular malfunction. We selected eight uncharacterized mutations and performed immunocytochemical and Western blot analyses to track cochlin through the secretory pathway. We then performed a comprehensive analysis of clinical information from DFNA9 patients with all 21 known COCH mutations in conjunction with cellular and molecular findings to identify genotype-phenotype correlations. Our studies revealed that five mutants were not secreted into the media: two von Willebrand factor A (vWFA) domain mutants, which were not transported from the endoplasmic reticulum to Golgi complex and formed high-molecular-weight aggregates in cell lysates, and three LCCL domain mutants, which were detected as intracellular dimeric cochlins. Mutant cochlins that were not secreted and accumulated in cells result in earlier age of onset of hearing defects. In addition, individuals with LCCL domain mutations show accompanying vestibular dysfunction, whereas those with vWFA domain mutations exhibit predominantly hearing loss. This is the first report showing failure of mutant cochlin transport through the secretory pathway, abolishment of cochlin secretion, and formation and retention of dimers and large multimeric intracellular aggregates, and high correlation with earlier onset and progression of hearing loss in individuals with these DFNA9-causing mutations.
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Affiliation(s)
- Seung-Hyun Bae
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea.,School of Life Sciences, KNU Creative BioResearch Group (BK21 plus program), Kyungpook National University
| | - Nahid G Robertson
- Department of Obstetrics & Gynecology, Brigham & Women's Hospital, Boston, MA, USA
| | - Hyun-Ju Cho
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea
| | - Cynthia C Morton
- Departments of Obstetrics & Gynecology and Pathology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, Broad Institute, Cambridge, MA, USA
| | - Da Jung Jung
- Department of Otolaryngology, College of Medicine, Kyungpook National University, Daegu, South Korea
| | - Jeong-In Baek
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Soo-Young Choi
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jaetae Lee
- Department of Nuclear Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Kyu-Yup Lee
- Department of Otolaryngology, College of Medicine, Kyungpook National University, Daegu, South Korea
| | - Un-Kyung Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu, South Korea.,School of Life Sciences, KNU Creative BioResearch Group (BK21 plus program), Kyungpook National University
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Clinical characterization of a novel COCH mutation G87V in a Chinese DFNA9 family. Int J Pediatr Otorhinolaryngol 2013; 77:1711-5. [PMID: 23993205 DOI: 10.1016/j.ijporl.2013.07.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/26/2013] [Accepted: 07/29/2013] [Indexed: 11/23/2022]
Abstract
OBJECTIVES To characterize the clinical features of a Chinese DFNA9 family associated with a novel COCH mutation and to confirm the proposed genotype-phenotype correlation of COCH. METHODS Mutation screening of 79 deafness genes was performed in the proband by targeted next-generation sequencing. Co-segregation of the disease phenotype and the detected variants was confirmed in all family members by PCR amplification and Sanger sequencing. The progression of hearing impairment in affected family members was followed and the concomitant vestibular dysfunction was verified by the caloric vestibulo-ocular reflex test. RESULTS A novel COCH mutation p.G87V was identified in the family segregating with late-onset, progressive sensorineural hearing impairment and consistent vestibular dysfunction. CONCLUSION The p.G87V mutation leads to a very similar phenotype as a previously reported p.G87W mutation of COCH. Our study suggested that the G87 residue is critical for function of COCH and further confirms a previously proposed genotype-phenotype correlation for DFNA9.
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ANGELI SIMON, LIN XI, LIU XUEZHONG. Genetics of hearing and deafness. Anat Rec (Hoboken) 2012; 295:1812-29. [PMID: 23044516 PMCID: PMC4523052 DOI: 10.1002/ar.22579] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 01/20/2023]
Abstract
This article is a review of the genes and genetic disorders that affect hearing in humans and a few selected mouse models of deafness. Genetics is playing an increasingly critical role in the practice of medicine. This is not only in part to the importance that genetic knowledge has on traditional genetic diseases but also in part to the fact that genetic knowledge provides an understanding of the fundamental biological process of most diseases. The proteins coded by the genes related to hearing loss (HL) are involved in many functions in the ear, such as cochlear fluid homeostasis, ionic channels, stereocilia morphology and function, synaptic transmission, gene regulation, and others. Mouse models play a crucial role in understanding of the pathogenesis associated with these genes. Different types of familial HL have been recognized for years; however, in the last two decades, there has been tremendous progress in the discovery of gene mutations that cause deafness. Most of the cases of genetic deafness recognized today are monogenic disorders that can be broadly classified by the mode of inheritance (i.e., autosomal dominant, autosomal recessive, X-linked, and mitochondrial inheritance) and by the presence of associated phenotypic features (i.e., syndromic; and nonsyndromic). In terms of nonsyndromic HL, the chromosomal locations are currently known for ∼ 125 loci (54 for dominant and 71 for recessive deafness), 64 genes have been identified (24 for dominant and 40 for recessive deafness), and there are many more loci for syndromic deafness and X-linked and mitochondrial DNA disorders (http://hereditaryhearingloss.org). Thus, today's clinician must understand the science of medical genetics as this knowledge can lead to more effective disease diagnosis, counseling, treatment, and prevention.
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Affiliation(s)
- SIMON ANGELI
- Department of Otolaryngology, University of Miami, Miami, Florida
| | - XI LIN
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, Georgia
| | - XUE ZHONG LIU
- Department of Otolaryngology, University of Miami, Miami, Florida
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Torgyekes E, Shanske AL, Anyane-Yeboa K, Nahum O, Pirzadeh S, Blumfield E, Jobanputra V, Warburton D, Levy B. The proximal chromosome 14q microdeletion syndrome: Delineation of the phenotype using high resolution SNP oligonucleotide microarray analysis (SOMA) and review of the literature. Am J Med Genet A 2011; 155A:1884-96. [DOI: 10.1002/ajmg.a.34090] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Accepted: 04/04/2011] [Indexed: 01/20/2023]
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Jones SM, Robertson NG, Given S, Giersch ABS, Liberman MC, Morton CC. Hearing and vestibular deficits in the Coch(-/-) null mouse model: comparison to the Coch(G88E/G88E) mouse and to DFNA9 hearing and balance disorder. Hear Res 2010; 272:42-8. [PMID: 21073934 DOI: 10.1016/j.heares.2010.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 10/28/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
Two mouse models, the Coch(G88E/G88E) or "knock-in" and the Coch(-/-) or "knock-out" (Coch null), have been developed to study the human late-onset, progressive, sensorineural hearing loss and vestibular dysfunction known as DFNA9. This disorder results from missense and in-frame deletion mutations in COCH (coagulation factor C homology), encoding cochlin, the most abundantly detected protein in the inner ear. We have performed hearing and vestibular analyses by auditory brainstem response (ABR) and vestibular evoked potential (VsEP) testing of the Coch(-/-) and Coch(G88E/G88E) mouse models. Both Coch(-/-) and Coch(G88E/G88E) mice show substantially elevated ABRs at 21 months of age, but only at the highest frequency tested for the former and all frequencies for the latter. At 21 months, 9 of 11 Coch(-/-) mice and 4 of 8 Coch(G88E/G88E) mice have absent ABRs. Interestingly Coch(-/+) mice do not show hearing deficits, in contrast to Coch(G88E/+), which demonstrate elevated ABR thresholds similar to homozyotes. These results corroborate the DFNA9 autosomal dominant mode of inheritance, in addition to the observation that haploinsufficiency of Coch does not result in impaired hearing. Vestibular evoked potential (VsEP) thresholds were analyzed using a two factor ANOVA (Age X Genotype). Elevated VsEP thresholds are detected in Coch(-/-) mice at 13 and 21 months, the two ages tested, and as early as seven months in the Coch(G88E/G88E) mice. These results indicate that in both mouse models, vestibular function is compromised before cochlear function. Analysis and comparison of hearing and vestibular function in these two DFNA9 mouse models, where deficits occur at such an advanced age, provide insight into the pathology of DFNA9 and age-related hearing loss and vestibular dysfunction as well as an opportunity to investigate potential interventional therapies.
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Affiliation(s)
- Sherri M Jones
- Department of Communication Sciences and Disorders, East Carolina University, Greenville, NC, USA
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22
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Yao J, Py BF, Zhu H, Bao J, Yuan J. Role of protein misfolding in DFNA9 hearing loss. J Biol Chem 2010; 285:14909-14919. [PMID: 20228067 DOI: 10.1074/jbc.m110.106724] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the COCH (coagulation factor C homology) gene have been attributed to DFNA9 (deafness, autosomal-dominant 9), an autosomal-dominant non-syndromic hearing loss disorder. However, the mechanisms responsible for DFNA9 hearing loss remain unknown. Here, we demonstrate that mutant cochlin, the protein product of the COCH gene, forms a stable dimer that is sensitive to reducing agent. In contrast, wild-type (WT) cochlin may form only dimers transiently. Interestingly, the presence of mutant cochlin can stabilize WT cochlin in dimer conformation, providing a possible mechanism for the dominant nature of DFNA9 mutations. Furthermore, the expression of mutant cochlin eventually induces WT cochlin to form stable oligomers that are resistant to reducing agent. Finally, we show that mutant cochlin is cytotoxic in vitro and in vivo. Our study suggests a possible molecular mechanism underlying DFNA9 hearing loss and provides an in vitro model that may be used to explore protein-misfolding diseases in general.
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Affiliation(s)
- Jianhua Yao
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Bénédicte F Py
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Hong Zhu
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115
| | - Jianxin Bao
- Department of Otolaryngology, Washington University, St. Louis, Missouri 63110
| | - Junying Yuan
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.
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Nagy I, Trexler M, Patthy L. The second von Willebrand type A domain of cochlin has high affinity for type I, type II and type IV collagens. FEBS Lett 2008; 582:4003-7. [PMID: 19013156 DOI: 10.1016/j.febslet.2008.10.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 10/25/2008] [Indexed: 10/21/2022]
Abstract
Cochlin is colocalized with type II collagen in the extracellular matrix of cochlea and has been suggested to interact with this collagen. Here we show that the second von Willebrand type A domain of cochlin has affinity for type II collagen, as well as type I and type IV collagens whereas the LCCL-domain of cochlin has no affinity for these proteins. The implications of these findings for the mechanism whereby cochlin mutations cause the dominant negative DFNA9-type hearing loss are discussed.
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Affiliation(s)
- Ildikó Nagy
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, P.O. Box 7, Karolina út 29, H-1518, Hungary
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Human hereditary hearing impairment: mouse models can help to solve the puzzle. Hum Genet 2008; 124:325-48. [DOI: 10.1007/s00439-008-0556-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 08/29/2008] [Indexed: 12/31/2022]
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Papa FT, Mencarelli MA, Caselli R, Katzaki E, Sampieri K, Meloni I, Ariani F, Longo I, Maggio A, Balestri P, Grosso S, Farnetani MA, Berardi R, Mari F, Renieri A. A 3 Mb deletion in 14q12 causes severe mental retardation, mild facial dysmorphisms and Rett-like features. Am J Med Genet A 2008; 146A:1994-8. [DOI: 10.1002/ajmg.a.32413] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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26
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Williamson RE, Darrow KN, Giersch ABS, Resendes BL, Huang M, Conrad GW, Chen ZY, Liberman MC, Morton CC, Tasheva ES. Expression studies of osteoglycin/mimecan (OGN) in the cochlea and auditory phenotype of Ogn-deficient mice. Hear Res 2007; 237:57-65. [PMID: 18243607 DOI: 10.1016/j.heares.2007.12.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 12/05/2007] [Accepted: 12/11/2007] [Indexed: 11/27/2022]
Abstract
Genes involved in the hearing process have been identified through both positional cloning efforts following genetic linkage studies of families with heritable deafness and by candidate gene approaches based on known functional properties or inner ear expression. The latter method of gene discovery may employ a tissue- or organ-specific approach. Through characterization of a human fetal cochlear cDNA library, we have identified transcripts that are preferentially and/or highly expressed in the cochlea. High expression in the cochlea may be suggestive of a fundamental role for a transcript in the auditory system. Herein we report the identification and characterization of a transcript from the cochlear cDNA library with abundant cochlear expression and unknown function that was subsequently determined to represent osteoglycin (OGN). Ogn-deficient mice, when analyzed by auditory brainstem response and distortion product otoacoustic emissions, have normal hearing thresholds.
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Cochlin isoforms and their interaction with CTL2 (SLC44A2) in the inner ear. J Assoc Res Otolaryngol 2007; 8:435-46. [PMID: 17926100 DOI: 10.1007/s10162-007-0099-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Accepted: 08/30/2007] [Indexed: 10/22/2022] Open
Abstract
Choline transporter-like protein 2 (CTL2) is a multi-transmembrane protein expressed on inner ear supporting cells that was discovered as a target of antibody-induced hearing loss. Its function is unknown. A 64 kDa band that consistently co-precipitates with CTL2 from inner ear extracts was identified by mass spectroscopy as cochlin. Cochlin is an abundant inner ear protein expressed as multiple isoforms. Its function is also unknown, but it is suspected to be an extracellular matrix component. Cochlin is mutated in individuals with DFNA9 hearing loss. To investigate the CTL2-cochlin interaction, antibodies were raised to a cochlin-specific peptide. The antibodies identify several cochlin polypeptides on western blots and are specific for cochlin. We show that the heterogeneity of the cochlin isoforms is caused, in part, by in vivo post-translational modification by N-glycosylation and, in part, caused by alternative splicing. We verified that antibody to CTL2 co-immunoprecipitates cochlin from the inner ear and antibody to cochlin co-immunoprecipitates CTL2. Using cochlear cross-sections, we show that CTL2 is more widely distributed than previously described, and its prominent expression on cells facing the scala media suggests a possible role in homeostasis. A prominent but previously unreported ribbon-like pattern of cochlin in the basilar membrane was demonstrated, suggesting an important role for cochlin in the structure of the basilar membrane. CTL2 and cochlin are expressed in close proximity in the inner sulcus, the spiral prominence, vessels, limbus, and spiral ligament. The possible functional significance of CTL2-cochlin interactions remains unknown.
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Robertson NG, Cremers CWRJ, Huygen PLM, Ikezono T, Krastins B, Kremer H, Kuo SF, Liberman MC, Merchant SN, Miller CE, Nadol JB, Sarracino DA, Verhagen WIM, Morton CC. Cochlin immunostaining of inner ear pathologic deposits and proteomic analysis in DFNA9 deafness and vestibular dysfunction. Hum Mol Genet 2006; 15:1071-85. [PMID: 16481359 DOI: 10.1093/hmg/ddl022] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Seven missense mutations and one in-frame deletion mutation have been reported in the coagulation factor C homology (COCH) gene, causing the adult-onset, progressive sensorineural hearing loss and vestibular disorder at the DFNA9 locus. Prevalence of COCH mutations worldwide is unknown, as there is no systematic screening effort for late-onset hearing disorders; however, to date, COCH mutations have been found on four continents and the possibility of COCH playing an important role in presbycusis and disorders of imbalance has been considered. Cochlin (encoded by COCH) has also been shown as a major target antigen for autoimmune sensorineural hearing loss. In this report, we present histopathology, immunohistochemistry and proteomic analyses of inner ear tissues from post-mortem DFNA9 temporal bone samples of an individual from a large Dutch kindred segregating the P51S mutation and adult human unaffected controls, and wild-type (+/+) and Coch null (-/-) knock-out mice. DFNA9 is an inner ear disorder with a unique histopathology showing loss of cellularity and aggregation of abundant homogeneous acellular eosinophilic deposits in the cochlear and vestibular labyrinths, similar to protein aggregation in well-known neurodegenerative disorders. By immunohistochemistry on the DFNA9 temporal bone sections, we have shown cochlin staining of the characteristic cochlear and vestibular deposits, indicating aggregation of cochlin in the same structures in which it is normally expressed. Proteomic analysis identified cochlin as the most abundant protein in mouse and human cochleae. The high-level expression and stability of cochlin in the inner ear, even in the absence and severe atrophy of the fibrocytes that normally express COCH, are shown through these studies and further elucidate the pathobiologic events occurring in DFNA9 leading to hearing loss and vestibular dysfunction.
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Affiliation(s)
- Nahid G Robertson
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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