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Miyoshi T, Vishwasrao H, Belyantseva I, Sajeevadathan M, Ishibashi Y, Adadey S, Harada N, Shroff H, Friedman T. Live-cell single-molecule fluorescence microscopy for protruding organelles reveals regulatory mechanisms of MYO7A-driven cargo transport in stereocilia of inner ear hair cells. RESEARCH SQUARE 2024:rs.3.rs-4369958. [PMID: 38826223 PMCID: PMC11142366 DOI: 10.21203/rs.3.rs-4369958/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Stereocilia are unidirectional F-actin-based cylindrical protrusions on the apical surface of inner ear hair cells and function as biological mechanosensors of sound and acceleration. Development of functional stereocilia requires motor activities of unconventional myosins to transport proteins necessary for elongating the F-actin cores and to assemble the mechanoelectrical transduction (MET) channel complex. However, how each myosin localizes in stereocilia using the energy from ATP hydrolysis is only partially understood. In this study, we develop a methodology for live-cell single-molecule fluorescence microscopy of organelles protruding from the apical surface using a dual-view light-sheet microscope, diSPIM. We demonstrate that MYO7A, a component of the MET machinery, traffics as a dimer in stereocilia. Movements of MYO7A are restricted when scaffolded by the plasma membrane and F-actin as mediated by MYO7A's interacting partners. Here, we discuss the technical details of our methodology and its future applications including analyses of cargo transportation in various organelles.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Thomas Friedman
- National Institute on Deafness and Other Communication Disorders, NIH
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2
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Miyoshi T, Vishwasrao HD, Belyantseva IA, Sajeevadathan M, Ishibashi Y, Adadey SM, Harada N, Shroff H, Friedman TB. Live-cell single-molecule fluorescence microscopy for protruding organelles reveals regulatory mechanisms of MYO7A-driven cargo transport in stereocilia of inner ear hair cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.04.590649. [PMID: 38766013 PMCID: PMC11100596 DOI: 10.1101/2024.05.04.590649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Stereocilia are unidirectional F-actin-based cylindrical protrusions on the apical surface of inner ear hair cells and function as biological mechanosensors of sound and acceleration. Development of functional stereocilia requires motor activities of unconventional myosins to transport proteins necessary for elongating the F-actin cores and to assemble the mechanoelectrical transduction (MET) channel complex. However, how each myosin localizes in stereocilia using the energy from ATP hydrolysis is only partially understood. In this study, we develop a methodology for live-cell single-molecule fluorescence microscopy of organelles protruding from the apical surface using a dual-view light-sheet microscope, diSPIM. We demonstrate that MYO7A, a component of the MET machinery, traffics as a dimer in stereocilia. Movements of MYO7A are restricted when scaffolded by the plasma membrane and F-actin as mediated by MYO7A's interacting partners. Here, we discuss the technical details of our methodology and its future applications including analyses of cargo transportation in various organelles.
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Affiliation(s)
- Takushi Miyoshi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
- Division of Molecular and Integrative Physiology, Department of Biomedical Sciences, Southern Illinois University School of Medicine, Carbondale, IL, 62901, USA
| | - Harshad D. Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Inna A. Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Mrudhula Sajeevadathan
- Division of Molecular and Integrative Physiology, Department of Biomedical Sciences, Southern Illinois University School of Medicine, Carbondale, IL, 62901, USA
| | - Yasuko Ishibashi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
- Inner Ear Gene Therapy Program, National Institute on Deafness and Other Communication Disorders, National Institute of Health, Bethesda, Maryland 20892, USA
| | - Samuel M. Adadey
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Narinobu Harada
- Hearing Research Laboratory, Harada ENT Clinic, Higashi-Osaka, Osaka, 577-0816, Japan
| | - Hari Shroff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, 20892, USA
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Miyoshi T, Belyantseva IA, Sajeevadathan M, Friedman TB. Pathophysiology of human hearing loss associated with variants in myosins. Front Physiol 2024; 15:1374901. [PMID: 38562617 PMCID: PMC10982375 DOI: 10.3389/fphys.2024.1374901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 02/21/2024] [Indexed: 04/04/2024] Open
Abstract
Deleterious variants of more than one hundred genes are associated with hearing loss including MYO3A, MYO6, MYO7A and MYO15A and two conventional myosins MYH9 and MYH14. Variants of MYO7A also manifest as Usher syndrome associated with dysfunction of the retina and vestibule as well as hearing loss. While the functions of MYH9 and MYH14 in the inner ear are debated, MYO3A, MYO6, MYO7A and MYO15A are expressed in inner ear hair cells along with class-I myosin MYO1C and are essential for developing and maintaining functional stereocilia on the apical surface of hair cells. Stereocilia are large, cylindrical, actin-rich protrusions functioning as biological mechanosensors to detect sound, acceleration and posture. The rigidity of stereocilia is sustained by highly crosslinked unidirectionally-oriented F-actin, which also provides a scaffold for various proteins including unconventional myosins and their cargo. Typical myosin molecules consist of an ATPase head motor domain to transmit forces to F-actin, a neck containing IQ-motifs that bind regulatory light chains and a tail region with motifs recognizing partners. Instead of long coiled-coil domains characterizing conventional myosins, the tails of unconventional myosins have various motifs to anchor or transport proteins and phospholipids along the F-actin core of a stereocilium. For these myosins, decades of studies have elucidated their biochemical properties, interacting partners in hair cells and variants associated with hearing loss. However, less is known about how myosins traffic in a stereocilium using their motor function, and how each variant correlates with a clinical condition including the severity and onset of hearing loss, mode of inheritance and presence of symptoms other than hearing loss. Here, we cover the domain structures and functions of myosins associated with hearing loss together with advances, open questions about trafficking of myosins in stereocilia and correlations between hundreds of variants in myosins annotated in ClinVar and the corresponding deafness phenotypes.
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Affiliation(s)
- Takushi Miyoshi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
- Division of Molecular and Integrative Physiology, Department of Biomedical Sciences, Southern Illinois University School of Medicine, Carbondale, IL, United States
| | - Inna A. Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Mrudhula Sajeevadathan
- Division of Molecular and Integrative Physiology, Department of Biomedical Sciences, Southern Illinois University School of Medicine, Carbondale, IL, United States
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
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Cirilo JA, Liao X, Perrin BJ, Yengo CM. The dynamics of actin protrusions can be controlled by tip-localized myosin motors. J Biol Chem 2024; 300:105516. [PMID: 38042485 PMCID: PMC10801316 DOI: 10.1016/j.jbc.2023.105516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
Class III myosins localize to inner ear hair cell stereocilia and are thought to be crucial for stereocilia length regulation. Mutations within the motor domain of MYO3A that disrupt its intrinsic motor properties have been associated with non-syndromic hearing loss, suggesting that the motor properties of MYO3A are critical for its function within stereocilia. In this study, we investigated the impact of a MYO3A hearing loss mutation, H442N, using both in vitro motor assays and cell biological studies. Our results demonstrate the mutation causes a dramatic increase in intrinsic motor properties, actin-activated ATPase and in vitro actin gliding velocity, as well as an increase in actin protrusion extension velocity. We propose that both "gain of function" and "loss of function" mutations in MYO3A can impair stereocilia length regulation, which is crucial for stereocilia formation during development and normal hearing. Furthermore, we generated chimeric MYO3A constructs that replace the MYO3A motor and neck domain with the motor and neck domain of other myosins. We found that duty ratio, fraction of ATPase cycle myosin is strongly bound to actin, is a critical motor property that dictates the ability to tip localize within filopodia. In addition, in vitro actin gliding velocities correlated extremely well with filopodial extension velocities over a wide range of gliding and extension velocities. Taken together, our data suggest a model in which tip-localized myosin motors exert force that slides the membrane tip-ward, which can combat membrane tension and enhance the actin polymerization rate that ultimately drives protrusion elongation.
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Affiliation(s)
- Joseph A Cirilo
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Xiayi Liao
- Department of Biology, Indiana University - Purdue University, Indianapolis, Indiana, USA
| | - Benjamin J Perrin
- Department of Biology, Indiana University - Purdue University, Indianapolis, Indiana, USA
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA.
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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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Sharma N, Kumari D, Panigrahi I, Khetarpal P. A systematic review of the monogenic causes of Non-Syndromic Hearing Loss (NSHL) and discussion of Current Diagnosis and Treatment options. Clin Genet 2023; 103:16-34. [PMID: 36089522 DOI: 10.1111/cge.14228] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 12/13/2022]
Abstract
Hearing impairment is one of the most widespread inheritable sensory disorder affecting at least 1 in every 1000 born. About two-third of hereditary hearing loss (HHL) disorders are non-syndromic. To provide comprehensive update of monogenic causes of non-syndromic hearing loss (NSHL), literature search has been carried out with appropriate keywords in the following databases-PubMed, Google Scholar, Cochrane library, and Science Direct. Out of 2214 papers, 271 papers were shortlisted after applying inclusion and exclusion criterion. Data extracted from selected papers include information about gene name, identified pathogenic variants, ethnicity of the patient, age of onset, gender, title, authors' name, and year of publication. Overall, pathogenic variants in 98 different genes have been associated with NSHL. These genes have important role to play during early embryonic development in ear structure formation and hearing development. Here, we also review briefly the recent information about diagnosis and treatment approaches. Understanding pathogenic genetic variants are helpful in the management of affected and may offer targeted therapies in future.
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Affiliation(s)
- Nandita Sharma
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
| | - Divya Kumari
- Department of Pediatrics Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Inusha Panigrahi
- Department of Pediatrics Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Preeti Khetarpal
- Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
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Souissi A, Abdelmalek Driss D, Chakchouk I, Ben Said M, Ben Ayed I, Mosrati MA, Elloumi I, Tlili A, Aifa S, Masmoudi S. Molecular insights into MYO3A kinase domain variants explain variability in both severity and progression of DFNB30 hearing impairment. J Biomol Struct Dyn 2022; 40:10940-10951. [PMID: 34423747 DOI: 10.1080/07391102.2021.1953600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Hereditary hearing impairment (HI) is a common disease with the highest incidence among sensory defects. Several genes have been identified to affect stereocilia structure causing HI, including the unconventional myosin3A. Interestingly, we noticed that variants in MYO3A gene have been previously found to cause variable HI onset and severity. Using clinical exome sequencing, we identified a novel pathogenic variant p.(Lys50Arg) in the MYO3A kinase domain (MYO3A-KD). Previous in vitro studies supported its damaging effect as a 'kinase-dead' mutant. We further analyzed this variation through molecular dynamics which predicts that changes in flexibility of MYO3A structure would influence the protein-ATP binding properties. This Lys50Arg mutation segregated with congenital profound non-syndromic HI. To better investigate this variability, we collected previously identified MYO3A-KDs variants, p.(Tyr129Cys), p.(His142Gln) and p.(Pro189Thr), and built both wild type and mutant 3 D MYO3A-KD models to assess their impact on the protein structure and function. Our results suggest that KD mutations could either cause a congenital profound form of HI, when particularly affecting the kinase activity and preventing the auto-phosphorylation of the motor, or a late onset and progressive form, when partially or completely inactivating the MYO3A protein. In conclusion, we report a novel pathogenic variant affecting the ATP-binding site within the MYO3A-KD causing congenital profound HI. Through computational approaches we provide a deeper understanding on the correlation between the effects of MYO3A-KD mutations and the variable hearing phenotypes. To the best of our knowledge this is the first study to correlate mutations' genotypes with the variable phenotypes of DFNB30.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Amal Souissi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Dorra Abdelmalek Driss
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Imen Chakchouk
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Ikhlas Ben Ayed
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.,Medical Genetic Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
| | - Mohamed Ali Mosrati
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Ines Elloumi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Abdelaziz Tlili
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates.,Human Genetics and Stem Cell Laboratory, Research Institute of Sciences and Engineering, University of Sharjah, Sharjah, United Arab Emirates
| | - Sami Aifa
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
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Miyoshi T, Belyantseva IA, Kitajiri SI, Miyajima H, Nishio SY, Usami SI, Kim BJ, Choi BY, Omori K, Shroff H, Friedman TB. Human deafness-associated variants alter the dynamics of key molecules in hair cell stereocilia F-actin cores. Hum Genet 2022; 141:363-382. [PMID: 34232383 PMCID: PMC11351816 DOI: 10.1007/s00439-021-02304-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/15/2021] [Indexed: 12/16/2022]
Abstract
Stereocilia protrude up to 100 µm from the apical surface of vertebrate inner ear hair cells and are packed with cross-linked filamentous actin (F-actin). They function as mechanical switches to convert sound vibration into electrochemical neuronal signals transmitted to the brain. Several genes encode molecular components of stereocilia including actin monomers, actin regulatory and bundling proteins, motor proteins and the proteins of the mechanotransduction complex. A stereocilium F-actin core is a dynamic system, which is continuously being remodeled while maintaining an outwardly stable architecture under the regulation of F-actin barbed-end cappers, severing proteins and crosslinkers. The F-actin cores of stereocilia also provide a pathway for motor proteins to transport cargos including components of tip-link densities, scaffolding proteins and actin regulatory proteins. Deficiencies and mutations of stereocilia components that disturb this "dynamic equilibrium" in stereocilia can induce morphological changes and disrupt mechanotransduction causing sensorineural hearing loss, best studied in mouse and zebrafish models. Currently, at least 23 genes, associated with human syndromic and nonsyndromic hearing loss, encode proteins involved in the development and maintenance of stereocilia F-actin cores. However, it is challenging to predict how variants associated with sensorineural hearing loss segregating in families affect protein function. Here, we review the functions of several molecular components of stereocilia F-actin cores and provide new data from our experimental approach to directly evaluate the pathogenicity and functional impact of reported and novel variants of DIAPH1 in autosomal-dominant DFNA1 hearing loss using single-molecule fluorescence microscopy.
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Affiliation(s)
- Takushi Miyoshi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, Room 1F-143A, Bethesda, MD, 20892, USA.
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan.
| | - Inna A Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, Room 1F-143A, Bethesda, MD, 20892, USA
| | - Shin-Ichiro Kitajiri
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 390-8621, Matsumoto, Japan
| | - Hiroki Miyajima
- Department of Otolaryngology, Shinshu University School of Medicine, Matsumoto, 390-8621, Japan
- Department of Otolaryngology, Aizawa Hospital, Matsumoto, 390-8510, Japan
| | - Shin-Ya Nishio
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 390-8621, Matsumoto, Japan
| | - Shin-Ichi Usami
- Department of Hearing Implant Sciences, Shinshu University School of Medicine, 390-8621, Matsumoto, Japan
| | - Bong Jik Kim
- Department of Otolaryngology-Head and Neck Surgery, Chungnam National University College of Medicine, Chungnam National University Sejong Hospital, Sejong, 30099, South Korea
- Brain Research Institute, Chungnam National University College of Medicine, Daejeon, 35015, South Korea
| | - Byung Yoon Choi
- Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seongnam, 13620, South Korea
| | - Koichi Omori
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, Japan
| | - Hari Shroff
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Porter Neuroscience Research Center, Room 1F-143A, Bethesda, MD, 20892, USA
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Frequency and origin of the c.2090T>G p.(Leu697Trp) MYO3A variant associated with autosomal dominant hearing loss. Eur J Hum Genet 2022; 30:13-21. [PMID: 33953343 PMCID: PMC8738757 DOI: 10.1038/s41431-021-00891-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/15/2021] [Accepted: 04/08/2021] [Indexed: 02/07/2023] Open
Abstract
We recently described a novel missense variant [c.2090T>G:p.(Leu697Trp)] in the MYO3A gene, found in two Brazilian families with late-onset autosomal dominant nonsyndromic hearing loss (ADNSHL). Since then, with the objective of evaluating its contribution to ADNSHL in Brazil, the variant was screened in additional 101 pedigrees with probable ADNSHL without conclusive molecular diagnosis. The variant was found in three additional families, explaining 3/101 (~3%) of cases with ADNSHL in our Brazilian pedigree collection. In order to identify the origin of the variant, 21 individuals from the five families were genotyped with a high-density SNP array (~600 K SNPs- Axiom Human Origins; ThermoFisher). The identity by descent (IBD) approach revealed that many pairs of individuals from the different families have a kinship coefficient equivalent to that of second cousins, and all share a minimum haplotype of ~607 kb which includes the c.2090T>G variant suggesting it probably arose in a common ancestor. We inferred that the mutation occurred in a chromosomal segment of European ancestry and the time since the most common ancestor was estimated in 1100 years (CI = 775-1425). This variant was also reported in a Dutch family, which shares a 87,121 bp haplotype with the Brazilian samples, suggesting that Dutch colonists may have brought it to Northeastern Brazil in the 17th century. Therefore, the present study opens new avenues to investigate this variant not only in Brazilians but also in European families with ADNSHL.
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10
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Gunther LK, Cirilo JA, Desetty R, Yengo CM. Deafness mutation in the MYO3A motor domain impairs actin protrusion elongation mechanism. Mol Biol Cell 2021; 33:ar5. [PMID: 34788109 PMCID: PMC8886822 DOI: 10.1091/mbc.e21-05-0232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Class III myosins are actin-based motors proposed to transport cargo to the distal tips of stereocilia in the inner ear hair cells and/or to participate in stereocilia length regulation, which is especially important during development. Mutations in the MYO3A gene are associated with delayed onset deafness. A previous study demonstrated that L697W, a dominant deafness mutation, disrupts MYO3A ATPase and motor properties but does not impair its ability to localize to the tips of actin protrusions. In the current study, we characterized the transient kinetic mechanism of the L697W motor ATPase cycle. Our kinetic analysis demonstrates that the mutation slows the ADP release and ATP hydrolysis steps, which results in a slight reduction in the duty ratio and slows detachment kinetics. Fluorescence recovery after photobleaching (FRAP) of filopodia tip localized L697W and WT MYO3A in COS-7 cells revealed that the mutant does not alter turnover or average intensity at the actin protrusion tips. We demonstrate that the mutation slows filopodia extension velocity in COS-7 cells which correlates with its twofold slower in vitro actin gliding velocity. Overall, this work allowed us to propose a model for how the motor properties of MYO3A are crucial for facilitating actin protrusion length regulation.
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Affiliation(s)
- Laura K Gunther
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, 17033
| | - Joseph A Cirilo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, 17033
| | - Rohini Desetty
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, 17033
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, 17033
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11
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Trigila AP, Pisciottano F, Franchini LF. Hearing loss genes reveal patterns of adaptive evolution at the coding and non-coding levels in mammals. BMC Biol 2021; 19:244. [PMID: 34784928 PMCID: PMC8594068 DOI: 10.1186/s12915-021-01170-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 10/21/2021] [Indexed: 11/26/2022] Open
Abstract
Background Mammals possess unique hearing capacities that differ significantly from those of the rest of the amniotes. In order to gain insights into the evolution of the mammalian inner ear, we aim to identify the set of genetic changes and the evolutionary forces that underlie this process. We hypothesize that genes that impair hearing when mutated in humans or in mice (hearing loss (HL) genes) must play important roles in the development and physiology of the inner ear and may have been targets of selective forces across the evolution of mammals. Additionally, we investigated if these HL genes underwent a human-specific evolutionary process that could underlie the evolution of phenotypic traits that characterize human hearing. Results We compiled a dataset of HL genes including non-syndromic deafness genes identified by genetic screenings in humans and mice. We found that many genes including those required for the normal function of the inner ear such as LOXHD1, TMC1, OTOF, CDH23, and PCDH15 show strong signatures of positive selection. We also found numerous noncoding accelerated regions in HL genes, and among them, we identified active transcriptional enhancers through functional enhancer assays in transgenic zebrafish. Conclusions Our results indicate that the key inner ear genes and regulatory regions underwent adaptive evolution in the basal branch of mammals and along the human-specific branch, suggesting that they could have played an important role in the functional remodeling of the cochlea. Altogether, our data suggest that morphological and functional evolution could be attained through molecular changes affecting both coding and noncoding regulatory regions. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01170-6.
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Affiliation(s)
- Anabella P Trigila
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina
| | - Francisco Pisciottano
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina.,Current address: Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina
| | - Lucía F Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina.
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12
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Cirilo JA, Gunther LK, Yengo CM. Functional Role of Class III Myosins in Hair Cells. Front Cell Dev Biol 2021; 9:643856. [PMID: 33718386 PMCID: PMC7947357 DOI: 10.3389/fcell.2021.643856] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/01/2021] [Indexed: 11/14/2022] Open
Abstract
Cytoskeletal motors produce force and motion using the energy from ATP hydrolysis and function in a variety of mechanical roles in cells including muscle contraction, cargo transport, and cell division. Actin-based myosin motors have been shown to play crucial roles in the development and function of the stereocilia of auditory and vestibular inner ear hair cells. Hair cells can contain hundreds of stereocilia, which rely on myosin motors to elongate, organize, and stabilize their structure. Mutations in many stereocilia-associated myosins have been shown to cause hearing loss in both humans and animal models suggesting that each myosin isoform has a specific function in these unique parallel actin bundle-based protrusions. Here we review what is known about the classes of myosins that function in the stereocilia, with a special focus on class III myosins that harbor point mutations associated with delayed onset hearing loss. Much has been learned about the role of the two class III myosin isoforms, MYO3A and MYO3B, in maintaining the precise stereocilia lengths required for normal hearing. We propose a model for how class III myosins play a key role in regulating stereocilia lengths and demonstrate how their motor and regulatory properties are particularly well suited for this function. We conclude that ongoing studies on class III myosins and other stereocilia-associated myosins are extremely important and may lead to novel therapeutic strategies for the treatment of hearing loss due to stereocilia degeneration.
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Affiliation(s)
- Joseph A Cirilo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States
| | - Laura K Gunther
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States
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13
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Vona B, Doll J, Hofrichter MAH, Haaf T, Varshney GK. Small fish, big prospects: using zebrafish to unravel the mechanisms of hereditary hearing loss. Hear Res 2020; 397:107906. [PMID: 32063424 PMCID: PMC7415493 DOI: 10.1016/j.heares.2020.107906] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/13/2020] [Accepted: 01/29/2020] [Indexed: 12/16/2022]
Abstract
Over the past decade, advancements in high-throughput sequencing have greatly enhanced our knowledge of the mutational signatures responsible for hereditary hearing loss. In its present state, the field has a largely uncensored view of protein coding changes in a growing number of genes that have been associated with hereditary hearing loss, and many more that have been proposed as candidate genes. Sequencing data can now be generated using methods that have become widespread and affordable. The greatest hurdles facing the field concern functional validation of uncharacterized genes and rapid application to human diseases, including hearing and balance disorders. To date, over 30 hearing-related disease models exist in zebrafish. New genome editing technologies, including CRISPR/Cas9 will accelerate the functional validation of hearing loss genes and variants in zebrafish. Here, we discuss current progress in the field and recent advances in genome editing approaches.
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Affiliation(s)
- Barbara Vona
- Department of Otolaryngology--Head & Neck Surgery, Tübingen Hearing Research Centre, Eberhard Karls University Tübingen, Tübingen, Germany.
| | - Julia Doll
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | | | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States.
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14
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Wonkam A, Manyisa N, Bope CD, Dandara C, Chimusa ER. Whole exome sequencing reveals pathogenic variants in MYO3A, MYO15A and COL9A3 and differential frequencies in ancestral alleles in hearing impairment genes among individuals from Cameroon. Hum Mol Genet 2020; 29:3729-3743. [PMID: 33078831 PMCID: PMC7861016 DOI: 10.1093/hmg/ddaa225] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 10/01/2020] [Accepted: 10/12/2020] [Indexed: 12/30/2022] Open
Abstract
There is scarcity of known gene variants of hearing impairment (HI) in African populations. This knowledge deficit is ultimately affecting the development of genetic diagnoses. We used whole exome sequencing to investigate gene variants, pathways of interactive genes and the fractions of ancestral overderived alleles for 159 HI genes among 18 Cameroonian patients with non-syndromic HI (NSHI) and 129 ethnically matched controls. Pathogenic and likely pathogenic (PLP) variants were found in MYO3A, MYO15A and COL9A3, with a resolution rate of 50% (9/18 patients). The study identified significant genetic differentiation in novel population-specific gene variants at FOXD4L2, DHRS2L6, RPL3L and VTN between HI patients and controls. These gene variants are found in functional/co-expressed interactive networks with other known HI-associated genes and in the same pathways with VTN being a hub protein, that is, focal adhesion pathway and regulation of the actin cytoskeleton (P-values <0.05). The results suggest that these novel population-specific gene variants are possible modifiers of the HI phenotypes. We found a high proportion of ancestral allele versus derived at low HI patients-specific minor allele frequency in the range of 0.0–0.1. The results showed a relatively low pickup rate of PLP variants in known genes in this group of Cameroonian patients with NSHI. In addition, findings may signal an evolutionary enrichment of some variants of HI genes in patients, as the result of polygenic adaptation, and suggest the possibility of multigenic influence on the phenotype of congenital HI, which deserves further investigations.
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Affiliation(s)
- Ambroise Wonkam
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa.,Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Noluthando Manyisa
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa
| | - Christian D Bope
- Department of Mathematics and Department of Computer Science, Faculty of Sciences, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Collet Dandara
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa
| | - Emile R Chimusa
- Division of Human Genetics, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa
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15
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Abstract
Myosins constitute a superfamily of actin-based molecular motor proteins that mediates a variety of cellular activities including muscle contraction, cell migration, intracellular transport, the formation of membrane projections, cell adhesion, and cell signaling. The 12 myosin classes that are expressed in humans share sequence similarities especially in the N-terminal motor domain; however, their enzymatic activities, regulation, ability to dimerize, binding partners, and cellular functions differ. It is becoming increasingly apparent that defects in myosins are associated with diseases including cardiomyopathies, colitis, glomerulosclerosis, neurological defects, cancer, blindness, and deafness. Here, we review the current state of knowledge regarding myosins and disease.
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16
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Gene therapy development in hearing research in China. Gene Ther 2020; 27:349-359. [PMID: 32681137 DOI: 10.1038/s41434-020-0177-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/13/2020] [Accepted: 07/08/2020] [Indexed: 12/15/2022]
Abstract
Sensorineural hearing loss, the most common form of hearing impairment, is mainly attributable to genetic mutations or acquired factors, such as aging, noise exposure, and ototoxic drugs. In the field of gene therapy, advances in genetic and physiological studies and profound increases in knowledge regarding the underlying mechanisms have yielded great progress in terms of restoring the auditory function in animal models of deafness. Nonetheless, many challenges associated with the translation from basic research to clinical therapies remain to be overcome before a total restoration of auditory function can be expected. In recent years, Chinese research teams have promoted various developmental efforts in this field, including gene sequencing to identify additional potential loci that cause deafness, studies to elucidate the underlying molecular mechanisms, and research to optimize vectors and delivery routes. In this review, we summarize the state of the field and focus mainly on the progress of gene therapy in animal model studies and the optimization of therapeutic strategies in China.
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Doll J, Hofrichter MAH, Bahena P, Heihoff A, Segebarth D, Müller T, Dittrich M, Haaf T, Vona B. A novel missense variant in MYO3A is associated with autosomal dominant high-frequency hearing loss in a German family. Mol Genet Genomic Med 2020; 8:e1343. [PMID: 32519820 PMCID: PMC7434730 DOI: 10.1002/mgg3.1343] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/16/2020] [Accepted: 05/19/2020] [Indexed: 12/30/2022] Open
Abstract
Background MYO3A, encoding the myosin IIIA protein, is associated with autosomal recessive and autosomal dominant nonsyndromic hearing loss. To date, only two missense variants located in the motor‐head domain of MYO3A have been described in autosomal dominant families with progressive, mild‐to‐profound sensorineural hearing loss. These variants alter the ATPase activity of myosin IIIA. Methods Exome sequencing of a proband from a three‐generation German family with prelingual, moderate‐to‐profound, high‐frequency hearing loss was performed. Segregation analysis confirmed a dominant inheritance pattern. Regression analysis of mean hearing level thresholds per individual and ear was performed at high‐, mid‐, and low‐frequencies. Results A novel heterozygous missense variant c.716T>C, p.(Leu239Pro) in the kinase domain of MYO3A was identified that is predicted in silico as disease causing. High‐frequency, progressive hearing loss was identified. Conclusion Correlation analysis of pure‐tone hearing thresholds revealed progressive hearing loss, especially in the high‐frequencies. In the present study, we report the first dominant likely pathogenic variant in MYO3A in a European family and further support MYO3A as an autosomal dominant hearing loss gene.
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Affiliation(s)
- Julia Doll
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | | | - Paulina Bahena
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | | | - Dennis Segebarth
- Institute of Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Tobias Müller
- Institute of Bioinformatics, Julius Maximilians University, Würzburg, Germany
| | - Marcus Dittrich
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany.,Institute of Bioinformatics, Julius Maximilians University, Würzburg, Germany
| | - Thomas Haaf
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany
| | - Barbara Vona
- Institute of Human Genetics, Julius Maximilians University, Würzburg, Germany.,Tübingen Hearing Research Centre, Department of Otolaryngology - Head and Neck Surgery, Eberhard Karls University, Tübingen, Germany
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18
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Friedman TB, Belyantseva IA, Frolenkov GI. Myosins and Hearing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1239:317-330. [DOI: 10.1007/978-3-030-38062-5_13] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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19
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Abstract
OBJECTIVE Literature review of the genetic etiology of hearing loss (HL) in the African American (AA) population. DATA SOURCES PubMed, EBSCO, and CINAHL were accessed from 1966 to 2018. REVIEW METHODS PRISMA guidelines were followed. Search terms included permutations of "hearing loss," "African American," "black," and "genetic"; "African American" was then cross-referenced against documented HL genes. AA subjects included in multiethnic cohorts of genetic HL testing were identified by searching the key terms "hearing loss" and "ethnic cohort" and "genetic." The Q-Genie tool was used in the quality assessment of included studies. An allele frequency meta-analysis of pathogenic GJB2 variants in the AA population was performed and stratified by hearing status. RESULTS Four hundred seventeen articles were reviewed, and 26 met our inclusion criteria. Ten studies were included in the GJB2 meta-analysis. In the general AA population, pathogenic GJB2 variants are rare, including the 35delG allele, which displayed a carrier frequency of 0.05%. Pathogenic variants were discovered in seven nonsyndromic HL genes (GJB2, MYO3A, TECTA, STRC, OTOF, MYH14, TMC1), eight syndromic HL genes, and one mitochondrial HL gene. Recent comprehensive genetic testing using custom genetic HL testing platforms has yielded only a 26% molecular diagnosis rate for HL etiologies in the AA population. CONCLUSIONS Investigators should be encouraged to provide an ethnic breakdown of results. Sparse literature and poor diagnosis rates indicate that genes involved in HL in the AA population have yet to be identified. Future explorative investigations using next-generation sequencing technologies, such as whole-exome sequencing, into the AA population are warranted.
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20
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Yizhar-Barnea O, Valensisi C, Jayavelu ND, Kishore K, Andrus C, Koffler-Brill T, Ushakov K, Perl K, Noy Y, Bhonker Y, Pelizzola M, Hawkins RD, Avraham KB. DNA methylation dynamics during embryonic development and postnatal maturation of the mouse auditory sensory epithelium. Sci Rep 2018; 8:17348. [PMID: 30478432 PMCID: PMC6255903 DOI: 10.1038/s41598-018-35587-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/08/2018] [Indexed: 12/17/2022] Open
Abstract
The inner ear is a complex structure responsible for hearing and balance, and organ pathology is associated with deafness and balance disorders. To evaluate the role of epigenomic dynamics, we performed whole genome bisulfite sequencing at key time points during the development and maturation of the mouse inner ear sensory epithelium (SE). Our single-nucleotide resolution maps revealed variations in both general characteristics and dynamics of DNA methylation over time. This allowed us to predict the location of non-coding regulatory regions and to identify several novel candidate regulatory factors, such as Bach2, that connect stage-specific regulatory elements to molecular features that drive the development and maturation of the SE. Constructing in silico regulatory networks around sites of differential methylation enabled us to link key inner ear regulators, such as Atoh1 and Stat3, to pathways responsible for cell lineage determination and maturation, such as the Notch pathway. We also discovered that a putative enhancer, defined as a low methylated region (LMR), can upregulate the GJB6 gene and a neighboring non-coding RNA. The study of inner ear SE methylomes revealed novel regulatory regions in the hearing organ, which may improve diagnostic capabilities, and has the potential to guide the development of therapeutics for hearing loss by providing multiple intervention points for manipulation of the auditory system.
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Affiliation(s)
- Ofer Yizhar-Barnea
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Cristina Valensisi
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Naresh Doni Jayavelu
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Kamal Kishore
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milano, 20139, Italy
| | - Colin Andrus
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Tal Koffler-Brill
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Kathy Ushakov
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Kobi Perl
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Yael Noy
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Yoni Bhonker
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Mattia Pelizzola
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milano, 20139, Italy
| | - R David Hawkins
- Division of Medical Genetics, Department of Medicine, Department of Genome Sciences, Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA.
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel.
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21
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Characterization of a novel MYO3A missense mutation associated with a dominant form of late onset hearing loss. Sci Rep 2018; 8:8706. [PMID: 29880844 PMCID: PMC5992146 DOI: 10.1038/s41598-018-26818-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/18/2018] [Indexed: 01/08/2023] Open
Abstract
Whole-exome sequencing of samples from affected members of two unrelated families with late-onset non-syndromic hearing loss revealed a novel mutation (c.2090 T > G; NM_017433) in MYO3A. The mutation was confirmed in 36 affected individuals, showing autosomal dominant inheritance. The mutation alters a single residue (L697W or p.Leu697Trp) in the motor domain of the stereocilia protein MYO3A, leading to a reduction in ATPase activity, motility, and an increase in actin affinity. MYO3A-L697W showed reduced filopodial actin protrusion initiation in COS7 cells, and a predominant tipward accumulation at filopodia and stereocilia when coexpressed with wild-type MYO3A and espin-1, an actin-regulatory MYO3A cargo. The combined higher actin affinity and duty ratio of the mutant myosin cause increased retention time at stereocilia tips, resulting in the displacement of the wild-type MYO3A protein, which may impact cargo transport, stereocilia length, and mechanotransduction. The dominant negative effect of the altered myosin function explains the dominant inheritance of deafness.
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22
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Rudman JR, Kabahuma RI, Bressler SE, Feng Y, Blanton SH, Yan D, Liu XZ. The genetic basis of deafness in populations of African descent. J Genet Genomics 2017; 44:285-294. [PMID: 28642064 DOI: 10.1016/j.jgg.2017.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/03/2017] [Accepted: 03/24/2017] [Indexed: 11/24/2022]
Abstract
Hearing loss is the most common sensorineural disorder worldwide and is associated with more than 1000 mutations in more than 90 genes. While mutations in genes such as GJB2 (gap-junction protein β 2) and GJB6 (gap-junction protein β 6) are highly prevalent in Caucasian, Asian, and Middle Eastern populations, they are rare in both native African populations and those of African descent. The objective of this paper is to review the current knowledge regarding the epidemiology and genetics of hearing loss in African populations with a focus on native sub-Saharan African populations. Environmental etiologies related to poor access to healthcare and perinatal care account for the majority of cases. Syndromic etiologies including Waardenburg, Pendred and Usher syndromes are uncommon causes of hearing loss in these populations. Of the non-syndromic causes, common mutations in GJB2 and GJB6 are rarely implicated in populations of African descent. Recent use of next-generation sequencing (NGS) has identified several candidate deafness genes in African populations from Nigeria and South Africa that are unique when compared to common causative mutations worldwide. Researchers also recently described a dominant mutation in MYO3a in an African American family with non-syndromic hearing loss. The use of NGS and specialized panels will aid in identifying rare and novel mutations in a more cost- and time-effective manner. The identification of common hearing loss mutations in indigenous African populations will pave the way for translation into genetic deafness research in populations of African descent worldwide.
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Affiliation(s)
- Jason R Rudman
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Rosemary I Kabahuma
- Department of Otorhinolaryngology, Steve Biko Academic Hospital, University of Pretoria, Pretoria 0001, South Africa.
| | - Sara E Bressler
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Yong Feng
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Susan H Blanton
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xue-Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410008, China; Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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23
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Mittal R, Debs LH, Nguyen D, Patel AP, Grati M, Mittal J, Yan D, Eshraghi AA, Liu XZ. Signaling in the Auditory System: Implications in Hair Cell Regeneration and Hearing Function. J Cell Physiol 2017; 232:2710-2721. [DOI: 10.1002/jcp.25695] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 11/18/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Luca H. Debs
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Desiree Nguyen
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Amit P. Patel
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - M'hamed Grati
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Jeenu Mittal
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Denise Yan
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Adrien A. Eshraghi
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
| | - Xue Zhong Liu
- Department of Otolaryngology; University of Miami Miller School of Medicine; Miami Florida
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24
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Plasma Membrane Targeting of Protocadherin 15 Is Regulated by the Golgi-Associated Chaperone Protein PIST. Neural Plast 2016; 2016:8580675. [PMID: 27867666 PMCID: PMC5102745 DOI: 10.1155/2016/8580675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/26/2016] [Indexed: 01/12/2023] Open
Abstract
Protocadherin 15 (PCDH15) is a core component of hair cell tip-links and crucial for proper function of inner ear hair cells. Mutations of PCDH15 gene cause syndromic and nonsyndromic hearing loss. At present, the regulatory mechanisms responsible for the intracellular transportation of PCDH15 largely remain unknown. Here we show that PIST, a Golgi-associated, PDZ domain-containing protein, interacts with PCDH15. The interaction is mediated by the PDZ domain of PIST and the C-terminal PDZ domain-binding interface (PBI) of PCDH15. Through this interaction, PIST retains PCDH15 in the trans-Golgi network (TGN) and reduces the membrane expression of PCDH15. We have previously showed that PIST regulates the membrane expression of another tip-link component, cadherin 23 (CDH23). Taken together, our finding suggests that PIST regulates the intracellular trafficking and membrane targeting of the tip-link proteins CDH23 and PCDH15.
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25
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Gurumurthy CB, Grati M, Ohtsuka M, Schilit SLP, Quadros RM, Liu XZ. CRISPR: a versatile tool for both forward and reverse genetics research. Hum Genet 2016; 135:971-6. [PMID: 27384229 PMCID: PMC5002245 DOI: 10.1007/s00439-016-1704-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/21/2016] [Indexed: 12/26/2022]
Abstract
Human genetics research employs the two opposing approaches of forward and reverse genetics. While forward genetics identifies and links a mutation to an observed disease etiology, reverse genetics induces mutations in model organisms to study their role in disease. In most cases, causality for mutations identified by forward genetics is confirmed by reverse genetics through the development of genetically engineered animal models and an assessment of whether the model can recapitulate the disease. While many technological advances have helped improve these approaches, some gaps still remain. CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated), which has emerged as a revolutionary genetic engineering tool, holds great promise for closing such gaps. By combining the benefits of forward and reverse genetics, it has dramatically expedited human genetics research. We provide a perspective on the power of CRISPR-based forward and reverse genetics tools in human genetics and discuss its applications using some disease examples.
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Affiliation(s)
- Channabasavaiah B Gurumurthy
- Developmental Neuroscience, Munroe Meyer Institute for Genetics and Rehabilitation, University of Nebraska Medical Center, Omaha, NE, USA.
- Mouse Genome Engineering Core Facility, Vice Chancellor for Research Office, University of Nebraska Medical Center, Omaha, NE, USA.
| | - M'hamed Grati
- Otolaryngology Department, University of Miami Miller School of Medicine, Miami, FL, USA.
| | - Masato Ohtsuka
- Department of Molecular Life Science, Division of Basic Medical Science and Molecular Medicine, School of Medicine, Tokai University, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
- The Institute of Medical Sciences, Tokai University, 143 Shimokasuya, Isehara, Kanagawa, 259-1193, Japan
| | - Samantha L P Schilit
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA
| | - Rolen M Quadros
- Mouse Genome Engineering Core Facility, Vice Chancellor for Research Office, University of Nebraska Medical Center, Omaha, NE, USA
| | - Xue Zhong Liu
- Otolaryngology Department, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, Hunan, China
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26
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Raval MH, Quintero OA, Weck ML, Unrath WC, Gallagher JW, Cui R, Kachar B, Tyska MJ, Yengo CM. Impact of the Motor and Tail Domains of Class III Myosins on Regulating the Formation and Elongation of Actin Protrusions. J Biol Chem 2016; 291:22781-22792. [PMID: 27582493 PMCID: PMC5077211 DOI: 10.1074/jbc.m116.733741] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 08/29/2016] [Indexed: 11/06/2022] Open
Abstract
Class III myosins (MYO3A and MYO3B) are proposed to function as transporters as well as length and ultrastructure regulators within stable actin-based protrusions such as stereocilia and calycal processes. MYO3A differs from MYO3B in that it contains an extended tail domain with an additional actin-binding motif. We examined how the properties of the motor and tail domains of human class III myosins impact their ability to enhance the formation and elongation of actin protrusions. Direct examination of the motor and enzymatic properties of human MYO3A and MYO3B revealed that MYO3A is a 2-fold faster motor with enhanced ATPase activity and actin affinity. A chimera in which the MYO3A tail was fused to the MYO3B motor demonstrated that motor activity correlates with formation and elongation of actin protrusions. We demonstrate that removal of individual exons (30-34) in the MYO3A tail does not prevent filopodia tip localization but abolishes the ability to enhance actin protrusion formation and elongation in COS7 cells. Interestingly, our results demonstrate that MYO3A slows filopodia dynamics and enhances filopodia lifetime in COS7 cells. We also demonstrate that MYO3A is more efficient than MYO3B at increasing formation and elongation of stable microvilli on the surface of cultured epithelial cells. We propose that the unique features of MYO3A, enhanced motor activity, and an extended tail with tail actin-binding motif, allow it to play an important role in stable actin protrusion length and ultrastructure maintenance.
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Affiliation(s)
- Manmeet H Raval
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033
| | - Omar A Quintero
- the Department of Biology, University of Richmond, Richmond, Virginia 23173
| | - Meredith L Weck
- the Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - William C Unrath
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033
| | - James W Gallagher
- the Department of Biology, Lincoln University, Philadelphia, Pennsylvania 19104, and
| | - Runjia Cui
- the Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, Bethesda, Maryland 20892
| | - Bechara Kachar
- the Laboratory of Cell Structure and Dynamics, NIDCD, National Institutes of Health, Bethesda, Maryland 20892
| | - Matthew J Tyska
- the Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Christopher M Yengo
- From the Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033,
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