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Jung J, Müller U. Mechanoelectrical transduction-related genetic forms of hearing loss. CURRENT OPINION IN PHYSIOLOGY 2023; 32:100632. [PMID: 36936795 PMCID: PMC10022594 DOI: 10.1016/j.cophys.2023.100632] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Hair cells of the mammalian cochlea are specialized mechanosensory cells that convert mechanical stimuli into electrical signals to initiate the neuronal responses that lead to the perception of sound. The mechanoelectrical transduction (MET) machinery of cochlear hair cells is a multimeric protein complex that consists of the pore forming subunits of the MET channel and several essential accessory subunits that are crucial to regulate channel function and render the channel mechanically sensitive. Mutations have been discovered in the genes that encode all known components of the MET machinery. These mutations cause hearing loss with or without vestibular dysfunction. Some mutations also affect other tissues such as the retina. In this brief review, we will summarize gene mutations that affect the MET machinery of hair cells and how the study of the affected genes has illuminated our understanding of the physiological role of the encoded proteins.
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Affiliation(s)
- Jinsei Jung
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Otorhinolaryngology, Graduate School of Medical Science, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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2
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Schäfer J, Wenck N, Janik K, Linnert J, Stingl K, Kohl S, Nagel-Wolfrum K, Wolfrum U. The Usher syndrome 1C protein harmonin regulates canonical Wnt signaling. Front Cell Dev Biol 2023; 11:1130058. [PMID: 36846582 PMCID: PMC9944737 DOI: 10.3389/fcell.2023.1130058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/23/2023] [Indexed: 02/11/2023] Open
Abstract
Human Usher syndrome (USH) is the most common form of hereditary combined deaf-blindness. USH is a complex genetic disorder, and the pathomechanisms underlying the disease are far from being understood, especially in the eye and retina. The USH1C gene encodes the scaffold protein harmonin which organizes protein networks due to binary interactions with other proteins, such as all USH proteins. Interestingly, only the retina and inner ear show a disease-related phenotype, although USH1C/harmonin is almost ubiquitously expressed in the human body and upregulated in colorectal cancer. We show that harmonin binds to β-catenin, the key effector of the canonical Wnt (cWnt) signaling pathway. We also demonstrate the interaction of the scaffold protein USH1C/harmonin with the stabilized acetylated β-catenin, especially in nuclei. In HEK293T cells, overexpression of USH1C/harmonin significantly reduced cWnt signaling, but a USH1C-R31* mutated form did not. Concordantly, we observed an increase in cWnt signaling in dermal fibroblasts derived from an USH1C R31*/R80Pfs*69 patient compared with healthy donor cells. RNAseq analysis reveals that both the expression of genes related to the cWnt signaling pathway and cWnt target genes were significantly altered in USH1C patient-derived fibroblasts compared to healthy donor cells. Finally, we show that the altered cWnt signaling was reverted in USH1C patient fibroblast cells by the application of Ataluren, a small molecule suitable to induce translational read-through of nonsense mutations, hereby restoring some USH1C expression. Our results demonstrate a cWnt signaling phenotype in USH establishing USH1C/harmonin as a suppressor of the cWnt/β-catenin pathway.
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Affiliation(s)
- Jessica Schäfer
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nicole Wenck
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katharina Janik
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Katarina Stingl
- Centre for Ophthalmology, University Eye Hospital, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany,Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology and Photoreceptor Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany,*Correspondence: Uwe Wolfrum,
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3
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Kim KS, Koo HY, Bok J. Alternative splicing in shaping the molecular landscape of the cochlea. Front Cell Dev Biol 2023; 11:1143428. [PMID: 36936679 PMCID: PMC10018040 DOI: 10.3389/fcell.2023.1143428] [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: 01/13/2023] [Accepted: 02/16/2023] [Indexed: 03/06/2023] Open
Abstract
The cochlea is a complex organ comprising diverse cell types with highly specialized morphology and function. Until now, the molecular underpinnings of its specializations have mostly been studied from a transcriptional perspective, but accumulating evidence points to post-transcriptional regulation as a major source of molecular diversity. Alternative splicing is one of the most prevalent and well-characterized post-transcriptional regulatory mechanisms. Many molecules important for hearing, such as cadherin 23 or harmonin, undergo alternative splicing to produce functionally distinct isoforms. Some isoforms are expressed specifically in the cochlea, while some show differential expression across the various cochlear cell types and anatomical regions. Clinical phenotypes that arise from mutations affecting specific splice variants testify to the functional relevance of these isoforms. All these clues point to an essential role for alternative splicing in shaping the unique molecular landscape of the cochlea. Although the regulatory mechanisms controlling alternative splicing in the cochlea are poorly characterized, there are animal models with defective splicing regulators that demonstrate the importance of RNA-binding proteins in maintaining cochlear function and cell survival. Recent technological breakthroughs offer exciting prospects for overcoming some of the long-standing hurdles that have complicated the analysis of alternative splicing in the cochlea. Efforts toward this end will help clarify how the remarkable diversity of the cochlear transcriptome is both established and maintained.
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Affiliation(s)
- Kwan Soo Kim
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
- Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hei Yeun Koo
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jinwoong Bok
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
- Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Republic of Korea
- *Correspondence: Jinwoong Bok,
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4
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Preclinical Models of Retinitis Pigmentosa. Methods Mol Biol 2022; 2560:181-215. [PMID: 36481897 DOI: 10.1007/978-1-0716-2651-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is the name for a group of phenotypically-related heritable retinal degenerative disorders. Many genes have been implicated as causing variants of RP, and while the clinical phenotypes are remarkably similar, they may differ in age of onset, progression, and severity. Common inheritance patterns for specific genes connected with the development of the disorder include autosomal dominant, autosomal recessive, and X-linked. Modeling the disease in animals and other preclinical systems offers a cost-conscious, ethical, and time-efficient method for studying the disease subtypes. The history of RP models is briefly examined, and both naturally occurring and transgenic preclinical models of RP in many different organisms are discussed. Syndromic forms of RP and models thereof are reviewed as well.
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5
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Qiu X, Müller U. Sensing sound: Cellular specializations and molecular force sensors. Neuron 2022; 110:3667-3687. [PMID: 36223766 PMCID: PMC9671866 DOI: 10.1016/j.neuron.2022.09.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/08/2022]
Abstract
Organisms of all phyla express mechanosensitive ion channels with a wide range of physiological functions. In recent years, several classes of mechanically gated ion channels have been identified. Some of these ion channels are intrinsically mechanosensitive. Others depend on accessory proteins to regulate their response to mechanical force. The mechanotransduction machinery of cochlear hair cells provides a particularly striking example of a complex force-sensing machine. This molecular ensemble is embedded into a specialized cellular compartment that is crucial for its function. Notably, mechanotransduction channels of cochlear hair cells are not only critical for auditory perception. They also shape their cellular environment and regulate the development of auditory circuitry. Here, we summarize recent discoveries that have shed light on the composition of the mechanotransduction machinery of cochlear hair cells and how this machinery contributes to the development and function of the auditory system.
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Affiliation(s)
- Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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6
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Yan W, Chen G, Li J. Structure of the Harmonin PDZ2 and coiled-coil domains in a complex with CDHR2 tail and its implications. FASEB J 2022; 36:e22425. [PMID: 35747925 DOI: 10.1096/fj.202200403rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/05/2022] [Accepted: 06/09/2022] [Indexed: 11/11/2022]
Abstract
Harmonin is a protein containing multiple PDZ domains and is required for the development and maintenance of hair cell stereocilia and brush border microvilli. Mutations in the USH1C gene can cause Usher syndrome type 1C, a severe inheritable disease characterized by the loss of hearing and vision. Here, by solving the high-resolution crystal structure of Harmonin PDZ2 and coiled-coil domains in a complex with the tail of cadherin-related family member 2, we demonstrated that mutations located in the Harmonin PDZ2 domain and found in patients could affect its stability, and thus, the target binding capability. The structure also implies that the coiled-coil domain could form antiparallel dimers under high concentrations, possibly when Harmonin underwent liquid-liquid phase separation in the upper tip-link density in hair cell stereocilia or microvilli of enterocytes of the intestinal epithelium. The crystal structure, together with the biochemical analysis, provided mechanistic implications for Harmonin mutations causing Usher syndrome, non-syndromic deafness, or enteropathy.
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Affiliation(s)
- Wenxia Yan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Guanhao Chen
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou, China
| | - Jianchao Li
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou, China.,Department of Otorhinolaryngology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, China
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7
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Grotz S, Schäfer J, Wunderlich KA, Ellederova Z, Auch H, Bähr A, Runa-Vochozkova P, Fadl J, Arnold V, Ardan T, Veith M, Santamaria G, Dhom G, Hitzl W, Kessler B, Eckardt C, Klein J, Brymova A, Linnert J, Kurome M, Zakharchenko V, Fischer A, Blutke A, Döring A, Suchankova S, Popelar J, Rodríguez-Bocanegra E, Dlugaiczyk J, Straka H, May-Simera H, Wang W, Laugwitz KL, Vandenberghe LH, Wolf E, Nagel-Wolfrum K, Peters T, Motlik J, Fischer MD, Wolfrum U, Klymiuk N. Early disruption of photoreceptor cell architecture and loss of vision in a humanized pig model of usher syndromes. EMBO Mol Med 2022; 14:e14817. [PMID: 35254721 PMCID: PMC8988205 DOI: 10.15252/emmm.202114817] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 02/04/2022] [Accepted: 02/09/2022] [Indexed: 01/17/2023] Open
Abstract
Usher syndrome (USH) is the most common form of monogenic deaf-blindness. Loss of vision is untreatable and there are no suitable animal models for testing therapeutic strategies of the ocular constituent of USH, so far. By introducing a human mutation into the harmonin-encoding USH1C gene in pigs, we generated the first translational animal model for USH type 1 with characteristic hearing defect, vestibular dysfunction, and visual impairment. Changes in photoreceptor architecture, quantitative motion analysis, and electroretinography were characteristics of the reduced retinal virtue in USH1C pigs. Fibroblasts from USH1C pigs or USH1C patients showed significantly elongated primary cilia, confirming USH as a true and general ciliopathy. Primary cells also proved their capacity for assessing the therapeutic potential of CRISPR/Cas-mediated gene repair or gene therapy in vitro. AAV-based delivery of harmonin into the eye of USH1C pigs indicated therapeutic efficacy in vivo.
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Affiliation(s)
- Sophia Grotz
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Jessica Schäfer
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Kirsten A Wunderlich
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Zdenka Ellederova
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Hannah Auch
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Andrea Bähr
- Center for Innovative Medical Models, LMU Munich, Munich, Germany.,Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Petra Runa-Vochozkova
- Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Janet Fadl
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Vanessa Arnold
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Taras Ardan
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Miroslav Veith
- Ophthalmology Clinic, University Hospital Kralovske Vinohrady, Praha, Czech Republic
| | - Gianluca Santamaria
- Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Georg Dhom
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Wolfgang Hitzl
- Biostatistics and Data Science, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kessler
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Christian Eckardt
- Center for Innovative Medical Models, LMU Munich, Munich, Germany.,Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Joshua Klein
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Anna Brymova
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Mayuko Kurome
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Valeri Zakharchenko
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Andrea Fischer
- Veterinary Faculty, Small Animal Clinics, LMU Munich, Munich, Germany
| | - Andreas Blutke
- Institute of Experimental Genetics, Helmholtz Center Munich, Neuherberg, Germany
| | - Anna Döring
- Veterinary Faculty, Small Animal Clinics, LMU Munich, Munich, Germany
| | - Stepanka Suchankova
- Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Jiri Popelar
- Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Eduardo Rodríguez-Bocanegra
- Centre for Ophthalmology, University Eye Hospital, University Hospital Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Julia Dlugaiczyk
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich (USZ), University of Zurich, Zurich, Switzerland
| | - Hans Straka
- Faculty of Biology, LMU Munich, Planegg, Germany
| | - Helen May-Simera
- Institute of Molecular Physiology, Cilia Biology, JGU Mainz, Mainz, Germany
| | - Weiwei Wang
- Grousbeck Gene Therapy Center, Mass Eye and Ear and Harvard Medical School, Boston, MA, USA
| | - Karl-Ludwig Laugwitz
- Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Luk H Vandenberghe
- Grousbeck Gene Therapy Center, Mass Eye and Ear and Harvard Medical School, Boston, MA, USA
| | - Eckhard Wolf
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany.,Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Tobias Peters
- Centre for Ophthalmology, University Eye Hospital, University Hospital Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Jan Motlik
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - M Dominik Fischer
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford, UK.,Nuffield Laboratory of Ophthalmology, NDCN, University of Oxford, Oxford, UK
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Nikolai Klymiuk
- Center for Innovative Medical Models, LMU Munich, Munich, Germany.,Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
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Abstract
Usher syndrome (USH) encompasses a group of clinically and genetically heterogenous disorders defined by the triad of sensorineural hearing loss (SNHL), vestibular dysfunction, and vision loss. USH is the most common cause of deaf blindness. USH is divided clinically into three subtypes-USH1, USH2, and USH3-based on symptom severity, progression, and age of onset. The underlying genetics of these USH forms are, however, significantly more complex, with over a dozen genes linked to the three primary clinical subtypes and other atypical USH phenotypes. Several of these genes are associated with other deaf-blindness syndromes that share significant clinical overlap with USH, pointing to the limits of a clinically based classification system. The genotype-phenotype relationships among USH forms also may vary significantly based on the location and type of mutation in the gene of interest. Understanding these genotype-phenotype relationships and associated natural disease histories is necessary for the successful development and application of gene-based therapies and precision medicine approaches to USH. Currently, the state of knowledge varies widely depending on the gene of interest. Recent studies utilizing next-generation sequencing technology have expanded the list of known pathogenic mutations in USH genes, identified new genes associated with USH-like phenotypes, and proposed algorithms to predict the phenotypic effects of specific categories of allelic variants. Further work is required to validate USH gene causality, and better define USH genotype-phenotype relationships and disease natural histories-particularly for rare mutations-to lay the groundwork for the future of USH treatment.
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Azadegan-Dehkordi F, Koohiyan M, Hoseini M. An update on autosomal recessive hearing loss and loci involved in it. INDIAN JOURNAL OF OTOLOGY 2022. [DOI: 10.4103/indianjotol.indianjotol_115_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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10
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Iglesias-Carres L, Neilson AP. Utilizing preclinical models of genetic diversity to improve translation of phytochemical activities from rodents to humans and inform personalized nutrition. Food Funct 2021; 12:11077-11105. [PMID: 34672309 DOI: 10.1039/d1fo02782d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mouse models are an essential tool in different areas of research, including nutrition and phytochemical research. Traditional inbred mouse models have allowed the discovery of therapeutical targets and mechanisms of action and expanded our knowledge of health and disease. However, these models lack the genetic variability typically found in human populations, which hinders the translatability of the results found in mice to humans. The development of genetically diverse mouse models, such as the collaborative cross (CC) or the diversity outbred (DO) models, has been a useful tool to overcome this obstacle in many fields, such as cancer, immunology and toxicology. However, these tools have not yet been widely adopted in the field of phytochemical research. As demonstrated in other disciplines, use of CC and DO models has the potential to provide invaluable insights for translation of phytochemicals from rodents to humans, which are desperately needed given the challenges and numerous failed clinical trials in this field. These models may prove informative for personalized use of phytochemicals in humans, including: predicting interindividual variability in phytochemical bioavailability and efficacy, identifying genetic loci or genes governing response to phytochemicals, identifying phytochemical mechanisms of action and therapeutic targets, and understanding the impact of genetic variability on individual response to phytochemicals. Such insights would prove invaluable for personalized implementation of phytochemicals in humans. This review will focus on the current work performed with genetically diverse mouse populations, and the research opportunities and advantages that these models can offer to phytochemical research.
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Affiliation(s)
- Lisard Iglesias-Carres
- Plants for Human Health Institute, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Kannapolis, NC, USA.
| | - Andrew P Neilson
- Plants for Human Health Institute, Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Kannapolis, NC, USA.
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11
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Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, Aller E, Jaijo T, Millán JM, García-García G. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci 2021; 22:ijms22136723. [PMID: 34201633 PMCID: PMC8268283 DOI: 10.3390/ijms22136723] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the “Usher interactome”. In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype–phenotype correlation.
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Affiliation(s)
- Carla Fuster-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Belén García-Bohórquez
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Correspondence:
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
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12
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Abstract
Congenital hearing loss is the most common birth defect, estimated to affect 2-3 in every 1000 births. Currently there is no cure for hearing loss. Treatment options are limited to hearing aids for mild and moderate cases, and cochlear implants for severe and profound hearing loss. Here we provide a literature overview of the environmental and genetic causes of congenital hearing loss, common animal models and methods used for hearing research, as well as recent advances towards developing therapies to treat congenital deafness. © 2021 The Authors.
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Affiliation(s)
- Justine M Renauld
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Martin L Basch
- Department of Otolaryngology, Head & Neck Surgery, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Department of Genetics and Genome Sciences, Case Western Reserve School of Medicine, Cleveland, Ohio.,Department of Biology, Case Western Reserve University, Cleveland, Ohio.,Department of Otolaryngology, Head & Neck Surgery, University Hospitals, Cleveland, Ohio
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13
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Whatley M, Francis A, Ng ZY, Khoh XE, Atlas MD, Dilley RJ, Wong EYM. Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy. Front Genet 2020; 11:565216. [PMID: 33193648 PMCID: PMC7642844 DOI: 10.3389/fgene.2020.565216] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped. The proteins encoded by these genes form complexes that play critical roles in the development and maintenance of cellular structures within the inner ear and retina, which have minimal capacity for repair or regeneration. In the cochlea, stereocilia are located on the apical surface of inner ear hair cells (HC) and are responsible for transducing mechanical stimuli from sound pressure waves into chemical signals. These signals are then detected by the auditory nerve fibers, transmitted to the brain and interpreted as sound. Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction. This review summarizes the current knowledge on Usher syndrome with a particular emphasis on mutations in USH genes, USH protein structures, and functional analyses in animal models. Currently, there is no cure for USH. However, the genetic therapies that are rapidly developing will benefit from this compilation of detailed genetic information to identify the most effective strategies for restoring functional USH proteins.
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Affiliation(s)
- Meg Whatley
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Abbie Francis
- Ear Science Institute Australia, Nedlands, WA, Australia
- Emergency Medicine, The University of Western Australia, Nedlands, WA, Australia
| | - Zi Ying Ng
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Xin Ee Khoh
- Ear Science Institute Australia, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
| | - Rodney J. Dilley
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Perth, WA, Australia
| | - Elaine Y. M. Wong
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
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14
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Zheng L, Yuan H, Zhang M, Wang C, Cai X, Liu J, Xu XQ. Rbm24 regulates inner-ear-specific alternative splicing and is essential for maintaining auditory and motor coordination. RNA Biol 2020; 18:468-480. [PMID: 32887533 DOI: 10.1080/15476286.2020.1817265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Tissue-specific alternative splicing (AS) is emerging as one of the most exciting types of mechanisms associated with organ development and disease. In the auditory system, many hearing-related genes undergo AS, and errors in this process result in syndromic or non-syndromic hearing loss. However, little is known about the factors and mechanisms directing AS in the inner ear. In the present study, we identified a novel RNA-binding protein, Rbm24, which was critically involved in regulating inner-ear-specific AS. Rbm24 deletion resulted in hearing loss and defects in motor coordination. Global splicing analysis showed Rbm24 was required for correct splicing of a subset of pre-mRNA transcripts with essential roles in stereocilia integrity and survival of hair cells. Furthermore, we identified that Rbm24 directly regulated the splicing of Cdh23, a known disease gene responsible for human Usher syndrome 1D and non-syndromic autosomal recessive deafness DFNB12. In conclusion, our findings demonstrated that Rbm24 was a critical factor in regulating inner-ear-specific splicing and maintaining the hearing and motor coordination function of the inner ear. Our data not only offer mechanistic insights but also provide functional annotation of Rbm24 splicing targets that contribute to hearing loss.
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Affiliation(s)
- Longqing Zheng
- The Institute of Stem Cell and Regenerative Medicine, School of Medicine, Xiamen University, Xiamen, China
| | - Huijun Yuan
- Medical Genetics Center, Southwest Hospital, Army Medical University, Chongqing, China
| | - Mengkai Zhang
- The Institute of Stem Cell and Regenerative Medicine, School of Medicine, Xiamen University, Xiamen, China
| | - Cuicui Wang
- Medical Genetics Center, Southwest Hospital, Army Medical University, Chongqing, China
| | - Xuemin Cai
- The Institute of Stem Cell and Regenerative Medicine, School of Medicine, Xiamen University, Xiamen, China
| | - Jing Liu
- The Institute of Stem Cell and Regenerative Medicine, School of Medicine, Xiamen University, Xiamen, China.,Shenzhen Research Institute, Xiamen University, P.R. China
| | - Xiu Qin Xu
- The Institute of Stem Cell and Regenerative Medicine, School of Medicine, Xiamen University, Xiamen, China
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15
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Yao Q, Wang L, Mittal R, Yan D, Richmond MT, Denyer S, Requena T, Liu K, Varshney GK, Lu Z, Liu XZ. Transcriptomic Analyses of Inner Ear Sensory Epithelia in Zebrafish. Anat Rec (Hoboken) 2019; 303:527-543. [PMID: 31883312 DOI: 10.1002/ar.24331] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 08/01/2019] [Accepted: 11/18/2019] [Indexed: 12/25/2022]
Abstract
Analysis of gene expression has the potential to assist in the understanding of multiple cellular processes including proliferation, cell-fate specification, senesence, and activity in both healthy and disease states. Zebrafish model has been increasingly used to understand the process of hearing and the development of the vertebrate auditory system. Within the zebrafish inner ear, there are three otolith organs, each containing a sensory macula of hair cells. The saccular macula is primarily involved in hearing, the utricular macula is primarily involved in balance and the function of the lagenar macula is not completely understood. The goal of this study is to understand the transcriptional differences in the sensory macula associated with different otolith organs with the intention of understanding the genetic mechanisms responsible for the distinct role each organ plays in sensory perception. The sensory maculae of the saccule, utricle, and lagena were dissected out of adult Et(krt4:GFP)sqet4 zebrafish expressing green fluorescent protein in hair cells for transcriptional analysis. The total RNAs of the maculae were isolated and analyzed by RNA GeneChip microarray. Several of the differentially expressed genes are known to be involved in deafness, otolith development and balance. Gene expression among these otolith organs was very well conserved with less than 10% of genes showing differential expression. Data from this study will help to elucidate which genes are involved in hearing and balance. Furthermore, the findings of this study will assist in the development of the zebrafish model for human hearing and balance disorders. Anat Rec, 303:527-543, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Qi Yao
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Biology, University of Miami, Miami, Florida
| | - Lingyu Wang
- Department of Biology, University of Miami, Miami, Florida
| | - Rahul Mittal
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Denise Yan
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida
| | | | - Steven Denyer
- Department of Biology, University of Miami, Miami, Florida
| | - Teresa Requena
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Kaili Liu
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Zhongmin Lu
- Department of Biology, University of Miami, Miami, Florida
| | - Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, Hunan, China
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16
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Tian C, Johnson KR. TBX1 is required for normal stria vascularis and semicircular canal development. Dev Biol 2019; 457:91-103. [PMID: 31550482 DOI: 10.1016/j.ydbio.2019.09.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/12/2019] [Accepted: 09/20/2019] [Indexed: 12/15/2022]
Abstract
Little is known about the role of TBX1 in post-otocyst stages of inner ear development. Here, we report on mice with a missense mutation of Tbx1 that are viable with fully developed but abnormally formed inner ears. Mutant mice are deaf due to an undeveloped stria vascularis and show vestibular dysfunction associated with abnormal semicircular canal formation. We show that TBX1 is expressed in endolymph-producing strial marginal cells and vestibular dark cells of the inner ear and is an upstream regulator of Esrrb, which previously was shown to control the developmental fate of these cells. We also show that TBX1 is expressed in sensory cells of the crista ampullaris, which may relate to the semicircular canal abnormalities observed in mutant mice. Inner ears of mutant embryos have a non-resorbed fusion plate in the posterior semicircular canal and a single ampulla connecting anterior and lateral canals. We hypothesize that the TBX1 missense mutation prevents binding with specific co-regulatory proteins. These findings reveal previously unknown functions of TBX1 during later stages of inner ear development.
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Affiliation(s)
- Cong Tian
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
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17
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Pangrsic T, Singer JH, Koschak A. Voltage-Gated Calcium Channels: Key Players in Sensory Coding in the Retina and the Inner Ear. Physiol Rev 2019; 98:2063-2096. [PMID: 30067155 DOI: 10.1152/physrev.00030.2017] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Calcium influx through voltage-gated Ca (CaV) channels is the first step in synaptic transmission. This review concerns CaV channels at ribbon synapses in primary sense organs and their specialization for efficient coding of stimuli in the physical environment. Specifically, we describe molecular, biochemical, and biophysical properties of the CaV channels in sensory receptor cells of the retina, cochlea, and vestibular apparatus, and we consider how such properties might change over the course of development and contribute to synaptic plasticity. We pay particular attention to factors affecting the spatial arrangement of CaV channels at presynaptic, ribbon-type active zones, because the spatial relationship between CaV channels and release sites has been shown to affect synapse function critically in a number of systems. Finally, we review identified synaptopathies affecting sensory systems and arising from dysfunction of L-type, CaV1.3, and CaV1.4 channels or their protein modulatory elements.
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Affiliation(s)
- Tina Pangrsic
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Joshua H Singer
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Alexandra Koschak
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
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18
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Blanco-Sánchez B, Clément A, Fierro J, Stednitz S, Phillips JB, Wegner J, Panlilio JM, Peirce JL, Washbourne P, Westerfield M. Grxcr1 Promotes Hair Bundle Development by Destabilizing the Physical Interaction between Harmonin and Sans Usher Syndrome Proteins. Cell Rep 2018; 25:1281-1291.e4. [PMID: 30380418 PMCID: PMC6284068 DOI: 10.1016/j.celrep.2018.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/11/2018] [Accepted: 09/28/2018] [Indexed: 01/02/2023] Open
Abstract
Morphogenesis and mechanoelectrical transduction of the hair cell mechanoreceptor depend on the correct assembly of Usher syndrome (USH) proteins into highly organized macromolecular complexes. Defects in these proteins lead to deafness and vestibular areflexia in USH patients. Mutations in a non-USH protein, glutaredoxin domain-containing cysteine-rich 1 (GRXCR1), cause non-syndromic sensorineural deafness. To understand the deglutathionylating enzyme function of GRXCR1 in deafness, we generated two grxcr1 zebrafish mutant alleles. We found that hair bundles are thinner in homozygous grxcr1 mutants, similar to the USH1 mutants ush1c (Harmonin) and ush1ga (Sans). In vitro assays showed that glutathionylation promotes the interaction between Ush1c and Ush1ga and that Grxcr1 regulates mechanoreceptor development by preventing physical interaction between these proteins without affecting the assembly of another USH1 protein complex, the Ush1c-Cadherin23-Myosin7aa tripartite complex. By elucidating the molecular mechanism through which Grxcr1 functions, we also identify a mechanism that dynamically regulates the formation of Usher protein complexes.
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Affiliation(s)
| | - Aurélie Clément
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Javier Fierro
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Sarah Stednitz
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Jeremy Wegner
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Judy L Peirce
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Philip Washbourne
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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19
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Mechanotransduction is required for establishing and maintaining mature inner hair cells and regulating efferent innervation. Nat Commun 2018; 9:4015. [PMID: 30275467 PMCID: PMC6167318 DOI: 10.1038/s41467-018-06307-w] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/21/2018] [Indexed: 12/13/2022] Open
Abstract
In the adult auditory organ, mechanoelectrical transducer (MET) channels are essential for transducing acoustic stimuli into electrical signals. In the absence of incoming sound, a fraction of the MET channels on top of the sensory hair cells are open, resulting in a sustained depolarizing current. By genetically manipulating the in vivo expression of molecular components of the MET apparatus, we show that during pre-hearing stages the MET current is essential for establishing the electrophysiological properties of mature inner hair cells (IHCs). If the MET current is abolished in adult IHCs, they revert into cells showing electrical and morphological features characteristic of pre-hearing IHCs, including the re-establishment of cholinergic efferent innervation. The MET current is thus critical for the maintenance of the functional properties of adult IHCs, implying a degree of plasticity in the mature auditory system in response to the absence of normal transduction of acoustic signals. Mechanoelectrical transducer (MET) channels on the tips of inner hair cells are essential for transducing auditory sensory information. Here, the authors show that disrupting MET channel function also prevents the preservation of normal inner hair cell identity in adult mice.
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20
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Booth KT, Kahrizi K, Babanejad M, Daghagh H, Bademci G, Arzhangi S, Zareabdollahi D, Duman D, El-Amraoui A, Tekin M, Najmabadi H, Azaiez H, Smith RJ. Variants in CIB2 cause DFNB48 and not USH1J. Clin Genet 2018; 93:812-821. [PMID: 29112224 PMCID: PMC5851821 DOI: 10.1111/cge.13170] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/31/2017] [Accepted: 11/02/2017] [Indexed: 12/16/2022]
Abstract
The genetic, mutational and phenotypic spectrum of deafness-causing genes shows great diversity and pleiotropy. The best examples are the group of genes, which when mutated can either cause non-syndromic hearing loss (NSHL) or the most common dual sensory impairment, Usher syndrome (USH). Variants in the CIB2 gene have been previously reported to cause hearing loss at the DFNB48 locus and deaf-blindness at the USH1J locus. In this study, we characterize the phenotypic spectrum in a multiethnic cohort with autosomal recessive non-syndromic hearing loss (ARNSHL) due to variants in the CIB2 gene. Of the 6 families we ascertained, 3 segregated novel loss-of-function (LOF) variants, 2 families segregated missense variants (1 novel) and 1 family segregated a previously reported pathogenic variant in trans with a frameshift variant. This report is the first to show that biallelic LOF variants in CIB2 cause ARNSHL and not USH. In the era of precision medicine, providing the correct diagnosis (NSHL vs USH) is essential for patient care as it impacts potential intervention and prevention options for patients. Here, we provide evidence disqualifying CIB2 as an USH-causing gene.
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Affiliation(s)
- Kevin T Booth
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology- Head and Neck Surgery, University of Iowa, Iowa City, Iowa
- Department of Molecular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mojgan Babanejad
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hossein Daghagh
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Guney Bademci
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida
| | - Sanaz Arzhangi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Davood Zareabdollahi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Duygu Duman
- Division of Pediatric Genetics, Ankara University School of Medicine, Ankara, Turkey
| | - Aziz El-Amraoui
- Institut Pasteur, Génétique et Physiologie de l’Audition, INSERM UMRS1120, UPMC Univ Paris06, 75015 Paris, France
| | - Mustafa Tekin
- John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation Department of Human Genetics, and Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, Florida
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Hela Azaiez
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology- Head and Neck Surgery, University of Iowa, Iowa City, Iowa
| | - Richard J Smith
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology- Head and Neck Surgery, University of Iowa, Iowa City, Iowa
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21
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Cone degeneration is triggered by the absence of USH1 proteins but prevented by antioxidant treatments. Sci Rep 2018; 8:1968. [PMID: 29386551 PMCID: PMC5792440 DOI: 10.1038/s41598-018-20171-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/04/2018] [Indexed: 11/26/2022] Open
Abstract
Usher syndrome type 1 (USH1) is a major cause of inherited deafness and blindness in humans. The eye disorder is often referred to as retinitis pigmentosa, which is characterized by a secondary cone degeneration following the rod loss. The development of treatments to prevent retinal degeneration has been hampered by the lack of clear evidence for retinal degeneration in mutant mice deficient for the Ush1 genes, which instead faithfully mimic the hearing deficit. We show that, under normal housing conditions, Ush1g−/− and Ush1c−/− albino mice have dysfunctional cone photoreceptors whereas pigmented knockout animals have normal photoreceptors. The key involvement of oxidative stress in photoreceptor apoptosis and the ensued retinal gliosis were further confirmed by their prevention when the mutant mice are reared under darkness and/or supplemented with antioxidants. The primary degeneration of cone photoreceptors contrasts with the typical forms of retinitis pigmentosa. Altogether, we propose that oxidative stress probably accounts for the high clinical heterogeneity among USH1 siblings, which also unveils potential targets for blindness prevention.
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22
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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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23
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Bowl MR, Simon MM, Ingham NJ, Greenaway S, Santos L, Cater H, Taylor S, Mason J, Kurbatova N, Pearson S, Bower LR, Clary DA, Meziane H, Reilly P, Minowa O, Kelsey L, Tocchini-Valentini GP, Gao X, Bradley A, Skarnes WC, Moore M, Beaudet AL, Justice MJ, Seavitt J, Dickinson ME, Wurst W, de Angelis MH, Herault Y, Wakana S, Nutter LMJ, Flenniken AM, McKerlie C, Murray SA, Svenson KL, Braun RE, West DB, Lloyd KCK, Adams DJ, White J, Karp N, Flicek P, Smedley D, Meehan TF, Parkinson HE, Teboul LM, Wells S, Steel KP, Mallon AM, Brown SDM. A large scale hearing loss screen reveals an extensive unexplored genetic landscape for auditory dysfunction. Nat Commun 2017; 8:886. [PMID: 29026089 PMCID: PMC5638796 DOI: 10.1038/s41467-017-00595-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 07/12/2017] [Indexed: 01/27/2023] Open
Abstract
The developmental and physiological complexity of the auditory system is likely reflected in the underlying set of genes involved in auditory function. In humans, over 150 non-syndromic loci have been identified, and there are more than 400 human genetic syndromes with a hearing loss component. Over 100 non-syndromic hearing loss genes have been identified in mouse and human, but we remain ignorant of the full extent of the genetic landscape involved in auditory dysfunction. As part of the International Mouse Phenotyping Consortium, we undertook a hearing loss screen in a cohort of 3006 mouse knockout strains. In total, we identify 67 candidate hearing loss genes. We detect known hearing loss genes, but the vast majority, 52, of the candidate genes were novel. Our analysis reveals a large and unexplored genetic landscape involved with auditory function.The full extent of the genetic basis for hearing impairment is unknown. Here, as part of the International Mouse Phenotyping Consortium, the authors perform a hearing loss screen in 3006 mouse knockout strains and identify 52 new candidate genes for genetic hearing loss.
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Affiliation(s)
- Michael R Bowl
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Michelle M Simon
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Neil J Ingham
- King's College London, London, SE1 1UL, UK
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Simon Greenaway
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Luis Santos
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Heather Cater
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Sarah Taylor
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Jeremy Mason
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1 SD, UK
| | - Natalja Kurbatova
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1 SD, UK
| | - Selina Pearson
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Lynette R Bower
- Mouse Biology Program, University of California, Davis, California, 95618, USA
| | - Dave A Clary
- Mouse Biology Program, University of California, Davis, California, 95618, USA
| | - Hamid Meziane
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), 1 rue Laurent Fries, Illkirch-Graffenstaden, F-67404, France
| | - Patrick Reilly
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), 1 rue Laurent Fries, Illkirch-Graffenstaden, F-67404, France
| | - Osamu Minowa
- RIKEN BioResource Center, Tsukuba, Ibaraki, 305-0074, Japan
| | - Lois Kelsey
- The Centre for Phenogenomics, Toronto, Ontario, Canada, M5T 3H7
- The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8
- Canada and Mount Sinai Hospital, Toronto, Ontario, Canada, M5G 1X5
| | - Glauco P Tocchini-Valentini
- Monterotondo Mouse Clinic, Italian National Research Council (CNR), Institute of Cell Biology and Neurobiology, I-00015, Monterotondo Scalo, Italy
| | - Xiang Gao
- SKL of Pharmaceutical Biotechnology and Model Animal Research Center, Collaborative Innovation Center for Genetics and Development, Nanjing Biomedical Research Institute, Nanjing University, 210061, Nanjing, China
| | - Allan Bradley
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - William C Skarnes
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Mark Moore
- IMPC, San Anselmo, California, 94960, USA
| | - Arthur L Beaudet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Monica J Justice
- The Centre for Phenogenomics, Toronto, Ontario, Canada, M5T 3H7
- The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8
- Canada and Mount Sinai Hospital, Toronto, Ontario, Canada, M5G 1X5
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - John Seavitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Mary E Dickinson
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
| | - Yann Herault
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), 1 rue Laurent Fries, Illkirch-Graffenstaden, F-67404, France
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg, 67404, Illkirch, France
- Centre National de la Recherche Scientifique, UMR7104, 67404, Illkirch, France
- Institut National de la Santé et de la Recherche Médicale, U964, 67404, Illkirch, France
| | | | - Lauryl M J Nutter
- The Centre for Phenogenomics, Toronto, Ontario, Canada, M5T 3H7
- The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8
- Canada and Mount Sinai Hospital, Toronto, Ontario, Canada, M5G 1X5
| | - Ann M Flenniken
- The Centre for Phenogenomics, Toronto, Ontario, Canada, M5T 3H7
- The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8
- Canada and Mount Sinai Hospital, Toronto, Ontario, Canada, M5G 1X5
| | - Colin McKerlie
- The Centre for Phenogenomics, Toronto, Ontario, Canada, M5T 3H7
- The Hospital for Sick Children, Toronto, Ontario, Canada, M5G 1X8
- Canada and Mount Sinai Hospital, Toronto, Ontario, Canada, M5G 1X5
| | | | | | | | - David B West
- Childrens' Hospital Oakland Research Institute, Oakland, California, 94609, USA
| | - K C Kent Lloyd
- Mouse Biology Program, University of California, Davis, California, 95618, USA
| | - David J Adams
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Jacqui White
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Natasha Karp
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1 SD, UK
| | | | - Terrence F Meehan
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1 SD, UK
| | - Helen E Parkinson
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1 SD, UK
| | - Lydia M Teboul
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Sara Wells
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Karen P Steel
- King's College London, London, SE1 1UL, UK
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Ann-Marie Mallon
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK
| | - Steve D M Brown
- Medical Research Council Harwell Institute (Mammalian Genetics Unit and Mary Lyon Centre), Harwell, Oxfordshire, OX11 0RD, UK.
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Bujakowska KM, Liu Q, Pierce EA. Photoreceptor Cilia and Retinal Ciliopathies. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028274. [PMID: 28289063 DOI: 10.1101/cshperspect.a028274] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Photoreceptors are sensory neurons designed to convert light stimuli into neurological responses. This process, called phototransduction, takes place in the outer segments (OS) of rod and cone photoreceptors. OS are specialized sensory cilia, with analogous structures to those present in other nonmotile cilia. Deficient morphogenesis and/or dysfunction of photoreceptor sensory cilia (PSC) caused by mutations in a variety of photoreceptor-specific and common cilia genes can lead to inherited retinal degenerations (IRDs). IRDs can manifest as isolated retinal diseases or syndromic diseases. In this review, we describe the structure and composition of PSC and different forms of ciliopathies with retinal involvement. We review the genetics of the IRDs, which are monogenic disorders but genetically diverse with regard to causality.
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Affiliation(s)
- Kinga M Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
| | - Qin Liu
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114
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25
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Corey DP, Ó Maoiléidigh D, Ashmore JF. Mechanical Transduction Processes in the Hair Cell. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-3-319-52073-5_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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26
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Myosin 7 and its adaptors link cadherins to actin. Nat Commun 2017; 8:15864. [PMID: 28660889 PMCID: PMC5493754 DOI: 10.1038/ncomms15864] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/03/2017] [Indexed: 12/17/2022] Open
Abstract
Cadherin linkages between adjacent stereocilia and microvilli are essential for mechanotransduction and maintaining their organization. They are anchored to actin through interaction of their cytoplasmic domains with related tripartite complexes consisting of a class VII myosin and adaptor proteins: Myo7a/SANS/Harmonin in stereocilia and Myo7b/ANKS4B/Harmonin in microvilli. Here, we determine high-resolution structures of Myo7a and Myo7b C-terminal MyTH4-FERM domain (MF2) and unveil how they recognize harmonin using a novel binding mode. Systematic definition of interactions between domains of the tripartite complex elucidates how the complex assembles and prevents possible self-association of harmonin-a. Several Myo7a deafness mutants that map to the surface of MF2 disrupt harmonin binding, revealing the molecular basis for how they impact the formation of the tripartite complex and disrupt mechanotransduction. Our results also suggest how switching between different harmonin isoforms can regulate the formation of networks with Myo7a motors and coordinate force sensing in stereocilia. Cadherin is essential for mechanotransduction and myosin-adaptor-harmonin complexes anchor it to actin. Here the authors present the structures of myosin 7 MF2 domains bound to the harmonin PDZ3c domain and give insights into myosin-adaptor-harmonin complex assembly.
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27
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Tian C, Harris BS, Johnson KR. Ectopic Mineralization and Conductive Hearing Loss in Enpp1asj Mutant Mice, a New Model for Otitis Media and Tympanosclerosis. PLoS One 2016; 11:e0168159. [PMID: 27959908 PMCID: PMC5154548 DOI: 10.1371/journal.pone.0168159] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 11/27/2016] [Indexed: 01/14/2023] Open
Abstract
Otitis media (OM), inflammation of the middle ear, is a common cause of hearing loss in children and in patients with many different syndromic diseases. Studies of the human population and mouse models have revealed that OM is a multifactorial disease with many environmental and genetic contributing factors. Here, we report on otitis media-related hearing loss in asj (ages with stiffened joints) mutant mice, which bear a point mutation in the Enpp1 gene. Auditory-evoked brainstem response (ABR) measurements revealed that around 90% of the mutant mice (Enpp1asj/asj) tested had moderate to severe hearing impairment in at least one ear. The ABR thresholds were variable and generally elevated with age. We found otitis media with effusion (OME) in all of the hearing-impaired Enpp1asj/asj mice by anatomic and histological examinations. The volume and inflammatory cell content of the effusion varied among the asj mutant mice, but all mutants exhibited a thickened middle ear epithelium with fibrous polyps and more mucin-secreting goblet cells than controls. Other abnormalities observed in the Enpp1 mutant mice include over-ossification at the round window ridge, thickened and over-calcified stapedial artery, fusion of malleus and incus, and white patches on the inside of tympanic membrane, some of which are typical symptoms of tympanosclerosis. An excessive yellow discharge was detected in the outer ear canal of older asj mutant mice, with 100% penetrance by 5 months of age, and contributes to the progressive nature of the hearing loss. This is the first report of hearing loss and ear pathology associated with an Enpp1 mutation in mice. The Enpp1asj mutant mouse provides a new animal model for studying tympanosclerotic otitis and otitis media with effusion, and also provides a specific model for the hearing loss recently reported to be associated with human ENPP1 mutations causing generalized arterial calcification of infancy and hypophosphatemic rickets.
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MESH Headings
- Animals
- Ear, Middle/pathology
- Ear, Middle/ultrastructure
- Genotype
- Hearing Loss, Conductive/genetics
- Hearing Loss, Conductive/pathology
- Inflammation
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mice, Transgenic
- Microscopy, Electron, Scanning
- Mutation
- Myringosclerosis/genetics
- Myringosclerosis/pathology
- Otitis Media/genetics
- Otitis Media/pathology
- Phosphoric Diester Hydrolases/genetics
- Pyrophosphatases/genetics
- Rickets, Hypophosphatemic/genetics
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Affiliation(s)
- Cong Tian
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, United States of America
- * E-mail:
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28
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Hair cells use active zones with different voltage dependence of Ca2+ influx to decompose sounds into complementary neural codes. Proc Natl Acad Sci U S A 2016; 113:E4716-25. [PMID: 27462107 DOI: 10.1073/pnas.1605737113] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
For sounds of a given frequency, spiral ganglion neurons (SGNs) with different thresholds and dynamic ranges collectively encode the wide range of audible sound pressures. Heterogeneity of synapses between inner hair cells (IHCs) and SGNs is an attractive candidate mechanism for generating complementary neural codes covering the entire dynamic range. Here, we quantified active zone (AZ) properties as a function of AZ position within mouse IHCs by combining patch clamp and imaging of presynaptic Ca(2+) influx and by immunohistochemistry. We report substantial AZ heterogeneity whereby the voltage of half-maximal activation of Ca(2+) influx ranged over ∼20 mV. Ca(2+) influx at AZs facing away from the ganglion activated at weaker depolarizations. Estimates of AZ size and Ca(2+) channel number were correlated and larger when AZs faced the ganglion. Disruption of the deafness gene GIPC3 in mice shifted the activation of presynaptic Ca(2+) influx to more hyperpolarized potentials and increased the spontaneous SGN discharge. Moreover, Gipc3 disruption enhanced Ca(2+) influx and exocytosis in IHCs, reversed the spatial gradient of maximal Ca(2+) influx in IHCs, and increased the maximal firing rate of SGNs at sound onset. We propose that IHCs diversify Ca(2+) channel properties among AZs and thereby contribute to decomposing auditory information into complementary representations in SGNs.
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Jansen F, Kalbe B, Scholz P, Mikosz M, Wunderlich KA, Kurtenbach S, Nagel-Wolfrum K, Wolfrum U, Hatt H, Osterloh S. Impact of the Usher syndrome on olfaction. Hum Mol Genet 2015; 25:524-33. [PMID: 26620972 DOI: 10.1093/hmg/ddv490] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/24/2015] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome is a genetically and clinically heterogeneous disease in humans, characterized by sensorineural hearing loss, retinitis pigmentosa and vestibular dysfunction. This disease is caused by mutations in genes encoding proteins that form complex networks in different cellular compartments. Currently, it remains unclear whether the Usher proteins also form networks within the olfactory epithelium (OE). Here, we describe Usher gene expression at the mRNA and protein level in the OE of mice and showed interactions between these proteins and olfactory signaling proteins. Additionally, we analyzed the odor sensitivity of different Usher syndrome mouse models using electro-olfactogram recordings and monitored significant changes in the odor detection capabilities in mice expressing mutant Usher proteins. Furthermore, we observed changes in the expression of signaling proteins that might compensate for the Usher protein deficiency. In summary, this study provides novel insights into the presence and purpose of the Usher proteins in olfactory signal transduction.
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Affiliation(s)
- Fabian Jansen
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, 44801 Bochum, Germany and
| | - Benjamin Kalbe
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, 44801 Bochum, Germany and
| | - Paul Scholz
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, 44801 Bochum, Germany and
| | - Marta Mikosz
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Kirsten A Wunderlich
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Stefan Kurtenbach
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, 44801 Bochum, Germany and
| | - Kerstin Nagel-Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Hanns Hatt
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, 44801 Bochum, Germany and
| | - Sabrina Osterloh
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-University Bochum, 44801 Bochum, Germany and
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30
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Falk N, Lösl M, Schröder N, Gießl A. Specialized Cilia in Mammalian Sensory Systems. Cells 2015; 4:500-19. [PMID: 26378583 PMCID: PMC4588048 DOI: 10.3390/cells4030500] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/04/2015] [Accepted: 09/09/2015] [Indexed: 02/01/2023] Open
Abstract
Cilia and flagella are highly conserved and important microtubule-based organelles that project from the surface of eukaryotic cells and act as antennae to sense extracellular signals. Moreover, cilia have emerged as key players in numerous physiological, developmental, and sensory processes such as hearing, olfaction, and photoreception. Genetic defects in ciliary proteins responsible for cilia formation, maintenance, or function underlie a wide array of human diseases like deafness, anosmia, and retinal degeneration in sensory systems. Impairment of more than one sensory organ results in numerous syndromic ciliary disorders like the autosomal recessive genetic diseases Bardet-Biedl and Usher syndrome. Here we describe the structure and distinct functional roles of cilia in sensory organs like the inner ear, the olfactory epithelium, and the retina of the mouse. The spectrum of ciliary function in fundamental cellular processes highlights the importance of elucidating ciliopathy-related proteins in order to find novel potential therapies.
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Affiliation(s)
- Nathalie Falk
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Marlene Lösl
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Nadja Schröder
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
| | - Andreas Gießl
- Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany.
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31
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Zhang X, Zheng T, Sang L, Apisa L, Zhao H, Fu F, Wang Q, Wang Y, Zheng Q. Otitis media induced by peptidoglycan-polysaccharide (PGPS) in TLR2-deficient (Tlr2(-/-)) mice for developing drug therapy. INFECTION GENETICS AND EVOLUTION 2015; 35:194-203. [PMID: 26296608 DOI: 10.1016/j.meegid.2015.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 08/12/2015] [Accepted: 08/17/2015] [Indexed: 12/14/2022]
Abstract
BACKGROUND Toll like receptor 2 (TLR2) signaling can regulate the pathogenesis of otitis media (OM). However, the precise role of TLR2 signaling in OM has not been clarified due to the lack of an optimal animal model. Peptidoglycan-polysaccharide (PGPS) of the bacterial cell wall can induce inflammation by activating the TLR2 signaling. This study aimed at examining the pathogenic characteristics of OM induced by PGPS in Tlr2(-/-) mice, and the potential therapeutic effect of sodium aescinate (SA) in this model. METHODS Wild-type (WT) and Tlr2(-/-) mice were inoculated with streptococcal PGPS into their middle ears (MEs) and treated intravenously with vehicle or SA daily beginning at 3days prior to PGPS for 6 consecutive days. The pathologic changes of individual mice were evaluated longitudinally. RESULTS In comparison with WT mice, Tlr2(-/-) mice were susceptible to PGPS-induced OM. Tlr2(-/-) mice displayed greater hearing loss, tympanic membrane damage, ME mucosal thickening, longer inflammation state, cilia and goblet cell loss. SA-treatment decreased neutrophil infiltration, modulated TLR2-related gene expression and improved ciliary organization. CONCLUSIONS PGPS induced a relatively stable OM in Tlr2(-/-) mice, providing a new model for OM research. Treatment with SA mitigated the pathogenic damage in the ME and may be valuable for intervention of OM.
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Affiliation(s)
- Xiaolin Zhang
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai 264003, Shandong, PR China; Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Tihua Zheng
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai 264003, Shandong, PR China
| | - Lu Sang
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai 264003, Shandong, PR China
| | - Luke Apisa
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Hongchun Zhao
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Affiliated Hospital of Binzhou Medical University, Binzhou 256600, Shandong, PR China
| | - Fenghua Fu
- Department of Pharmacology, School of Pharmacy, Yantai University, Yantai 264003, Shandong, PR China
| | - Qingzhu Wang
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai 264003, Shandong, PR China
| | - Yanfei Wang
- Department of Otolaryngology/Head and Neck Surgery, Institute of Otolaryngology, Affiliated Hospital of Binzhou Medical University, Binzhou 256600, Shandong, PR China.
| | - Qingyin Zheng
- Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai 264003, Shandong, PR China; Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, OH 44106, USA.
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Toms M, Bitner-Glindzicz M, Webster A, Moosajee M. Usher syndrome: a review of the clinical phenotype, genes and therapeutic strategies. EXPERT REVIEW OF OPHTHALMOLOGY 2015. [DOI: 10.1586/17469899.2015.1033403] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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33
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Bujakowska KM, Consugar M, Place E, Harper S, Lena J, Taub DG, White J, Navarro-Gomez D, Weigel DiFranco C, Farkas MH, Gai X, Berson EL, Pierce EA. Targeted exon sequencing in Usher syndrome type I. Invest Ophthalmol Vis Sci 2014; 55:8488-96. [PMID: 25468891 PMCID: PMC4280089 DOI: 10.1167/iovs.14-15169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Accepted: 11/16/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Patients with Usher syndrome type I (USH1) have retinitis pigmentosa, profound congenital hearing loss, and vestibular ataxia. This syndrome is currently thought to be associated with at least six genes, which are encoded by over 180 exons. Here, we present the use of state-of-the-art techniques in the molecular diagnosis of a cohort of 47 USH1 probands. METHODS The cohort was studied with selective exon capture and next-generation sequencing of currently known inherited retinal degeneration genes, comparative genomic hybridization, and Sanger sequencing of new USH1 exons identified by human retinal transcriptome analysis. RESULTS With this approach, we were able to genetically solve 14 of the 47 probands by confirming the biallelic inheritance of mutations. We detected two likely pathogenic variants in an additional 19 patients, for whom family members were not available for cosegregation analysis to confirm biallelic inheritance. Ten patients, in addition to primary disease-causing mutations, carried rare likely pathogenic USH1 alleles or variants in other genes associated with deaf-blindness, which may influence disease phenotype. Twenty-one of the identified mutations were novel among the 33 definite or likely solved patients. Here, we also present a clinical description of the studied cohort at their initial visits. CONCLUSIONS We found a remarkable genetic heterogeneity in the studied USH1 cohort with multiplicity of mutations, of which many were novel. No obvious influence of genotype on phenotype was found, possibly due to small sample sizes of the genotypes under study.
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Affiliation(s)
- Kinga M. Bujakowska
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Mark Consugar
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Emily Place
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Shyana Harper
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Jaclyn Lena
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Daniel G. Taub
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Joseph White
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Daniel Navarro-Gomez
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Carol Weigel DiFranco
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Michael H. Farkas
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Xiaowu Gai
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Eliot L. Berson
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
| | - Eric A. Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States
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Genetics of auditory mechano-electrical transduction. Pflugers Arch 2014; 467:49-72. [PMID: 24957570 PMCID: PMC4281357 DOI: 10.1007/s00424-014-1552-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 12/29/2022]
Abstract
The hair bundles of cochlear hair cells play a central role in the auditory mechano-electrical transduction (MET) process. The identification of MET components and of associated molecular complexes by biochemical approaches is impeded by the very small number of hair cells within the cochlea. In contrast, human and mouse genetics have proven to be particularly powerful. The study of inherited forms of deafness led to the discovery of several essential proteins of the MET machinery, which are currently used as entry points to decipher the associated molecular networks. Notably, MET relies not only on the MET machinery but also on several elements ensuring the proper sound-induced oscillation of the hair bundle or the ionic environment necessary to drive the MET current. Here, we review the most significant advances in the molecular bases of the MET process that emerged from the genetics of hearing.
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The retinal phenotype of Usher syndrome: pathophysiological insights from animal models. C R Biol 2014; 337:167-77. [PMID: 24702843 DOI: 10.1016/j.crvi.2013.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 12/03/2013] [Indexed: 01/26/2023]
Abstract
The Usher syndrome (USH) is the most prevalent cause of inherited deaf-blindness. Three clinical subtypes, USH1-3, have been defined, and ten USH genes identified. The hearing impairment due to USH gene defects has been shown to result from improper organisation of the hair bundle, the sound receptive structure of sensory hair cells. In contrast, the cellular basis of the visual defect is less well understood as this phenotype is absent in almost all the USH mouse models that faithfully mimic the human hearing impairment. Structural and molecular interspecies discrepancies regarding photoreceptor calyceal processes and the association with the distribution of USH1 proteins have recently been unravelled, and have led to the conclusion that a defect in the USH1 protein complex-mediated connection between the photoreceptor outer segment and the surrounding calyceal processes (in both rods and cones), and the inner segment (in rods only), probably causes the USH1 retinal dystrophy in humans.
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Sheykholeslami K, Thimmappa V, Nava C, Bai X, Yu H, Zheng T, Zhang Z, Li SL, Liu S, Zheng QY. A new mutation of the Atoh1 gene in mice with normal life span allows analysis of inner ear and cerebellar phenotype in aging. PLoS One 2013; 8:e79791. [PMID: 24265785 PMCID: PMC3827170 DOI: 10.1371/journal.pone.0079791] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 09/25/2013] [Indexed: 12/30/2022] Open
Abstract
Atoh1 is a transcription factor that regulates neural development in multiple tissues and is conserved among species. Prior mouse models of Atoh1, though effective and important in the evolution of our understanding of the gene, have been limited by perinatal lethality. Here we describe a novel point mutation of Atoh1 (designated Atoh1trhl) underlying a phenotype of trembling gait and hearing loss. Histology revealed inner ear hair cell loss and cerebellar atrophy. Auditory Brainstem Response (ABR) and Distortion Product Otoacoustic Emission (DPOAE) showed functional abnormalities in the ear. Normal lifespan and fecundity of Atoh1trhlmice provide a complementary model to facilitate elucidation of ATOH1 function in hearing,central nervous system and cancer biology.
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Affiliation(s)
- Kianoush Sheykholeslami
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Vikrum Thimmappa
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Casey Nava
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Xiaohui Bai
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Heping Yu
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Tihua Zheng
- The Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong, People's Republic of China
- Department of Biochemistry, Dalian Medical University, Dalian, People's Republic of China
| | - Zhaoqiang Zhang
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Sheng Li Li
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Shuqing Liu
- Department of Biochemistry, Dalian Medical University, Dalian, People's Republic of China
| | - Qing Yin Zheng
- Department of Otolaryngology-HNS, Case Western Reserve University, Cleveland, Ohio, United States of America
- The Transformative Otology and Neuroscience Center, Binzhou Medical University, Yantai, Shandong, People's Republic of China
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail:
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37
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Abstract
The 10 different genes associated with the deaf/blind disorder, Usher syndrome, encode a number of structurally and functionally distinct proteins, most expressed as multiple isoforms/protein variants. Functional characterization of these proteins suggests a role in stereocilia development in cochlear hair cells, likely owing to adhesive interactions in hair bundles. In mature hair cells, homodimers of the Usher cadherins, cadherin 23 and protocadherin 15, interact to form a structural fiber, the tip link, and the linkages that anchor the taller stereocilia's actin cytoskeleton core to the shorter adjacent stereocilia and the elusive mechanotransduction channels, explaining the deafness phenotype when these molecular interactions are perturbed. The conundrum is that photoreceptors lack a synonymous mechanotransduction apparatus, and so a common theory for Usher protein function in the two neurosensory cell types affected in Usher syndrome is lacking. Recent evidence linking photoreceptor cell dysfunction in the shaker 1 mouse model for Usher syndrome to light-induced protein translocation defects, combined with localization of an Usher protein interactome at the periciliary region of the photoreceptors suggests Usher proteins might regulate protein trafficking between the inner and outer segments of photoreceptors. A distinct Usher protein complex is trafficked to the ribbon synapses of hair cells, and synaptic defects have been reported in Usher mutants in both hair cells and photoreceptors. This review aims to clarify what is known about Usher protein function at the synaptic and apical poles of hair cells and photoreceptors and the prospects for identifying a unifying pathobiological mechanism to explain deaf/blindness in Usher syndrome.
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38
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Lee KY. Pathophysiology of age-related hearing loss (peripheral and central). KOREAN JOURNAL OF AUDIOLOGY 2013; 17:45-9. [PMID: 24653905 PMCID: PMC3936539 DOI: 10.7874/kja.2013.17.2.45] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 08/02/2013] [Accepted: 08/07/2013] [Indexed: 11/22/2022]
Abstract
Age-related hearing loss (presbycusis) refers to bilaterally symmetrical hearing loss resulting from aging process. Presbycusis is a complex phenomenon characterized by audiometric threshold shift, deterioration in speech-understanding and speech-perception difficulties in noisy environments. Factors contributing to presbycusis include mitochondria DNA mutation, genetic disorders including Ahl, hypertension, diabetes, metabolic disease and other systemic diseases in the intrinsic aspects. Extrinsic factors include noise, ototoxic medication and diet. However, presbycusis may not be related to the intrinsic and extrinsic factors separately. Presbycusis affects not only the physical, cognitive and emotional activities of patients, but also their social functioning. As a result, patients' quality of life deteriorates, compounded by various symptoms including depression, social isolation and lower self-esteem. Presbycusis is classified into six categories, as based on results of audiometric tests and temporal bone pathology, established by Schuknecht (1993): sensory, neural, metabolic or strial, cochlear conductive, mixed and indeterminate types. Among these, metabolic presbycusis is the mainstay of presbycusis types. Age-related changes also develop in the central hearing system. Functional decline of the central auditory system, caused by aging, reduces speech-understanding in noisy background and increase temporal processing deficits in gap-detection measures. This study reviews the literature on the age-related hearing loss.
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Affiliation(s)
- Kyu-Yup Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, School of Medicine, Kyungpook National University, Daegu, Korea
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39
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Papal S, Cortese M, Legendre K, Sorusch N, Dragavon J, Sahly I, Shorte S, Wolfrum U, Petit C, El-Amraoui A. The giant spectrin βV couples the molecular motors to phototransduction and Usher syndrome type I proteins along their trafficking route. Hum Mol Genet 2013; 22:3773-88. [PMID: 23704327 DOI: 10.1093/hmg/ddt228] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mutations in the myosin VIIa gene cause Usher syndrome type IB (USH1B), characterized by deaf-blindness. A delay of opsin trafficking has been observed in the retinal photoreceptor cells of myosin VIIa-deficient mice. We identified spectrin βV, the mammalian β-heavy spectrin, as a myosin VIIa- and rhodopsin-interacting partner in photoreceptor cells. Spectrin βV displays a polarized distribution from the Golgi apparatus to the base of the outer segment, which, unlike that of other β spectrins, matches the trafficking route of opsin and other phototransduction proteins. Formation of spectrin βV-rhodopsin complex could be detected in the differentiating photoreceptors as soon as their outer segment emerges. A failure of the spectrin βV-mediated coupling between myosin VIIa and opsin molecules thus probably accounts for the opsin transport delay in myosin VIIa-deficient mice. We showed that spectrin βV also associates with two USH1 proteins, sans (USH1G) and harmonin (USH1C). Spectrins are supposed to function as heteromers of α and β subunits, but fluorescence resonance energy transfer and in vitro binding experiments indicated that spectrin βV can also form homodimers, which likely supports its αII-independent βV functions. Finally, consistent with its distribution along the connecting cilia axonemes, spectrin βV binds to several subunits of the microtubule-based motor proteins, kinesin II and the dynein complex. We therefore suggest that spectrin βV homomers couple some USH1 proteins, opsin and other phototransduction proteins to both actin- and microtubule-based motors, thereby contributing to their transport towards the photoreceptor outer disks.
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Affiliation(s)
- Samantha Papal
- Institut Pasteur, Unité de génétique et physiologie de l'audition, Paris, France
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40
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Gregory FD, Pangrsic T, Calin-Jageman IE, Moser T, Lee A. Harmonin enhances voltage-dependent facilitation of Cav1.3 channels and synchronous exocytosis in mouse inner hair cells. J Physiol 2013; 591:3253-69. [PMID: 23613530 DOI: 10.1113/jphysiol.2013.254367] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cav1.3 channels mediate Ca(2+) influx that triggers exocytosis of glutamate at cochlear inner hair cell (IHC) synapses. Harmonin is a PDZ-domain-containing protein that interacts with the C-terminus of the Cav1.3 α1 subunit (α11.3) and controls cell surface Cav1.3 levels by promoting ubiquitin-dependent proteosomal degradation. However, PDZ-domain-containing proteins have diverse functions and regulate other Cav1.3 properties, which could collectively influence presynaptic transmitter release. Here, we report that harmonin binding to the α11.3 distal C-terminus (dCT) enhances voltage-dependent facilitation (VDF) of Cav1.3 currents both in transfected HEK293T cells and in mouse inner hair cells. In HEK293T cells, this effect of harmonin was greater for Cav1.3 channels containing the auxiliary Cav β1 than with the β2 auxiliary subunit. Cav1.3 channels lacking the α11.3 dCT were insensitive to harmonin modulation. Moreover, the 'deaf-circler' dfcr mutant form of harmonin, which does not interact with the α11.3 dCT, did not promote VDF. In mature IHCs from mice expressing the dfcr harmonin mutant, Cav1.3 VDF was less than in control IHCs. This difference was not observed between control and dfcr IHCs prior to hearing onset. Membrane capacitance recordings from dfcr IHCs revealed a role for harmonin in synchronous exocytosis and in increasing the efficiency of Ca(2+) influx for triggering exocytosis. Collectively, our results indicate a multifaceted presynaptic role of harmonin in IHCs in regulating Cav1.3 Ca(2+) channels and exocytosis.
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Affiliation(s)
- Frederick D Gregory
- Department of Molecular Physiology and Biophysics, University of Iowa, 5-610 Bowen Science Building, 51 Newton Rd, Iowa City, IA 52242, USA
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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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42
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Sahly I, Dufour E, Schietroma C, Michel V, Bahloul A, Perfettini I, Pepermans E, Estivalet A, Carette D, Aghaie A, Ebermann I, Lelli A, Iribarne M, Hardelin JP, Weil D, Sahel JA, El-Amraoui A, Petit C. Localization of Usher 1 proteins to the photoreceptor calyceal processes, which are absent from mice. ACTA ACUST UNITED AC 2012; 199:381-99. [PMID: 23045546 PMCID: PMC3471240 DOI: 10.1083/jcb.201202012] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mechanisms underlying retinal dystrophy in Usher syndrome type I (USH1) remain unknown because mutant mice lacking any of the USH1 proteins-myosin VIIa, harmonin, cadherin-23, protocadherin-15, sans-do not display retinal degeneration. We found here that, in macaque photoreceptor cells, all USH1 proteins colocalized at membrane interfaces (i) between the inner and outer segments in rods and (ii) between the microvillus-like calyceal processes and the outer segment basolateral region in rods and cones. This pattern, conserved in humans and frogs, was mediated by the formation of an USH1 protein network, which was associated with the calyceal processes from the early embryonic stages of outer segment growth onwards. By contrast, mouse photoreceptors lacked calyceal processes and had no USH1 proteins at the inner-outer segment interface. We suggest that USH1 proteins form an adhesion belt around the basolateral region of the photoreceptor outer segment in humans, and that defects in this structure cause the retinal degeneration in USH1 patients.
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Affiliation(s)
- Iman Sahly
- Institut de la vision, Syndrome de Usher et autres Atteintes Rétino-Cochléaires, 75012 Paris, France
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43
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Kikkawa Y, Seki Y, Okumura K, Ohshiba Y, Miyasaka Y, Suzuki S, Ozaki M, Matsuoka K, Noguchi Y, Yonekawa H. Advantages of a mouse model for human hearing impairment. Exp Anim 2012; 61:85-98. [PMID: 22531723 DOI: 10.1538/expanim.61.85] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Hearing is a major factor in human quality of life. Mouse models are important tools for discovering the genes that are responsible for genetic hearing loss, and these models often allow the processes that regulate the onset of deafness in humans to be analyzed. Thus far, in the study of hearing and deafness, at least 400 mutants with hearing impairments have been identified in laboratory mouse populations. Analysis of through a combination of genetic, morphological, and physiological studies is revealing valuable insights into the ontogenesis, morphogenesis, and function of the mammalian ear. This review discusses the advantages of the mouse models of human hearing impairment and highlights the identification of the molecules required for stereocilia development in the inner ear hair cells by analysis of various mouse mutants.
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Affiliation(s)
- Yoshiaki Kikkawa
- Mammalian Genetics Project, Department of Genome Medicine, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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44
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Huang Q, Zhang Z, Zheng Y, Zheng Q, Chen S, Xu Y, Ou Y, Qiu Z. Hypoxia-inducible factor and vascular endothelial growth factor pathway for the study of hypoxia in a new model of otitis media with effusion. Audiol Neurootol 2012; 17:349-56. [PMID: 22907120 DOI: 10.1159/000341163] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 06/18/2012] [Indexed: 02/04/2023] Open
Abstract
The hypoxia-inducible factor and vascular endothelial growth factor (HIF-VEGF) pathway in hypoxic conditions of the middle ear due to dysfunction of the eustachian tube is still unknown, but it is considered as one pathogenetic mechanism in otitis media. This study was designed to investigate the possible involvement of the HIF-VEFG pathway in otitis media with effusion induced by dysfunction of the eustachian tube. We adopted a soft palate approach to obstruct the orifice of the eustachian tube to establish otitis media in a rat model. Auditory evoked brainstem response and tympanometry were used as hearing function tests, hypoxia-related factors were examined by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of hypoxia-related proteins was detected by Western blot and immunostaining. The model of otitis media with effusion was successfully induced by cauterizing the orifice of the eustachian tube. RT-PCR showed up-regulation of hypoxia-related factors in cauterized ears. Western blot and immunostaining showed that the expression of hypoxia-related proteins in cauterized ears was increased. Hypoxia-induced vascular proliferation and an increase in permeability may be one pathogenetic mechanism of otitis media due to dysfunction of the eustachian tube.
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Affiliation(s)
- Qiuhong Huang
- Department of Otolaryngology-HNS, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, PR China
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45
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Pan L, Zhang M. Structures of usher syndrome 1 proteins and their complexes. Physiology (Bethesda) 2012; 27:25-42. [PMID: 22311968 DOI: 10.1152/physiol.00037.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Usher syndrome 1 (USH1) is the most common and severe form of hereditary loss of hearing and vision. Genetic, physiological, and cell biological studies, together with recent structural investigations, have not only uncovered the physiological functions of the five USH1 proteins but also provided mechanistic explanations for the hearing and visual deficiencies in humans caused by USH1 mutations. This review focuses on the structural basis of the USH1 protein complex organization.
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Affiliation(s)
- Lifeng Pan
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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46
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Hollingsworth TJ, Gross AK. Defective trafficking of rhodopsin and its role in retinal degenerations. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 293:1-44. [PMID: 22251557 DOI: 10.1016/b978-0-12-394304-0.00006-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Retinitis pigmentosa is a retinal degeneration transmitted by varied modes of inheritance and affects approximately 1 in 4000 individuals. The photoreceptors of the outer retina, as well as the retinal pigmented epithelium which supports the outer retina metabolically and structurally, are the retinal regions most affected by the disorder. In several forms of retinitis pigmentosa, the mislocalization of the rod photoreceptor protein rhodopsin is thought to be a contributing factor underlying the pathophysiology seen in patients. The mutations causing this mislocalization often occur in genes coding proteins involved in ciliary formation, vesicular transport, rod outer segment disc formation, and stability, as well as the rhodopsin protein itself. Often, these mutations result in the most early-onset cases of both recessive and dominant retinitis pigmentosa, and the following presents a discussion of the proteins, their degenerative phenotypes, and possible treatments of the disease.
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Affiliation(s)
- T J Hollingsworth
- Department of Vision Sciences, University of Alabama, Birmingham, Alabama, USA
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47
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Kazmierczak P, Müller U. Sensing sound: molecules that orchestrate mechanotransduction by hair cells. Trends Neurosci 2011; 35:220-9. [PMID: 22177415 DOI: 10.1016/j.tins.2011.10.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/25/2011] [Accepted: 10/27/2011] [Indexed: 01/19/2023]
Abstract
Animals use acoustic signals to communicate and to obtain information about their environment. The processing of acoustic signals is initiated at auditory sense organs, where mechanosensory hair cells convert sound-induced vibrations into electrical signals. Although the biophysical principles underlying the mechanotransduction process in hair cells have been characterized in much detail over the past 30 years, the molecular building-blocks of the mechanotransduction machinery have proved to be difficult to determine. We review here recent studies that have both identified some of these molecules and established the mechanisms by which they regulate the activity of the still-elusive mechanotransduction channel.
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Affiliation(s)
- Piotr Kazmierczak
- Dorris Neuroscience Center, Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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48
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Abstract
Hereditary deafness is genetically heterogeneous such that mutations of many different genes can cause hearing loss. This review focuses on the evidence and implications that several of these deafness genes encode actin-interacting proteins or actin itself. There is a growing appreciation of the contribution of the actin interactome in stereocilia development, maintenance, mechanotransduction and malfunction of the auditory system.
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49
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Gregory FD, Bryan KE, Pangršič T, Calin-Jageman IE, Moser T, Lee A. Harmonin inhibits presynaptic Cav1.3 Ca²⁺ channels in mouse inner hair cells. Nat Neurosci 2011; 14:1109-11. [PMID: 21822269 PMCID: PMC3164920 DOI: 10.1038/nn.2895] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Accepted: 06/27/2011] [Indexed: 11/22/2022]
Abstract
Harmonin is a scaffolding protein required for normal mechanosensory function in hair cells. Here, we describe a novel presynaptic association of harmonin and Cav1.3 Ca2+ channels at the mouse inner hair cell synapse, which limits channel availability through a ubiquitin-dependent pathway.
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Affiliation(s)
- Frederick D Gregory
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, USA
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50
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Phillips JB, Blanco-Sanchez B, Lentz JJ, Tallafuss A, Khanobdee K, Sampath S, Jacobs ZG, Han PF, Mishra M, Titus TA, Williams DS, Keats BJ, Washbourne P, Westerfield M. Harmonin (Ush1c) is required in zebrafish Müller glial cells for photoreceptor synaptic development and function. Dis Model Mech 2011; 4:786-800. [PMID: 21757509 PMCID: PMC3209648 DOI: 10.1242/dmm.006429] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Usher syndrome is the most prevalent cause of hereditary deaf-blindness, characterized by congenital sensorineural hearing impairment and progressive photoreceptor degeneration beginning in childhood or adolescence. Diagnosis and management of this disease are complex, and the molecular changes underlying sensory cell impairment remain poorly understood. Here we characterize two zebrafish models for a severe form of Usher syndrome, Usher syndrome type 1C (USH1C): one model is a mutant with a newly identified ush1c nonsense mutation, and the other is a morpholino knockdown of ush1c. Both have defects in hearing, balance and visual function from the first week of life. Histological analyses reveal specific defects in sensory cell structure that are consistent with these behavioral phenotypes and could implicate Müller glia in the retinal pathology of Usher syndrome. This study shows that visual defects associated with loss of ush1c function in zebrafish can be detected from the onset of vision, and thus could be applicable to early diagnosis for USH1C patients.
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