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Sun J, Ren D, Gong M, Guo X, Zhang Y, Du B. Identification of novel CDH23 variants linked to hearing loss in a Chinese family: A case report. Medicine (Baltimore) 2024; 103:e39360. [PMID: 39287240 PMCID: PMC11404951 DOI: 10.1097/md.0000000000039360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/19/2024] Open
Abstract
RATIONALE Deafness is associated with both environmental and genetic factors, with hereditary deafness often caused by mutations in deafness-related genes. Identifying and analyzing deafness-related genes will aid in early diagnosis and pave the way for treating inherited deafness through gene therapy in the future. PATIENT CONCERNS A 15-month-old girl underwent audiological examination at the outpatient clinic of the hospital due to hearing loss and her brother was diagnosed with profound bilateral sensorineural hearing loss at the age of 3. DIAGNOSES The diagnosis was determined as extremely severe sensorineural hearing loss caused by genetic factors. INTERVENTIONS Clinical data of the patient were collected, and peripheral blood samples were obtained from both the patient and her family members for DNA extraction and sequencing. OUTCOMES By utilizing targeted capture next-generation sequencing to further screen for deafness-related genes, 2 novel variants in CDH23 were identified as the causative factors for the patient's deafness. LESSONS This study identified 2 novel heterozygous mutations in a Chinese family. Both the proband and her sibling have non-syndromic hearing loss (NSHL) and carry distinct heterozygous mutations of cadherin-like 23 (CDH23). One mutation, CDH23:c.2651 A>G, originated from their mother and paternal family, affecting the exon23 domain of CDH23. The other mutation, CDH23:c.2113 G>T, was inherited from their paternal grandmother, impacting the exon19 domain of CDH23. These 2 novel mutations likely cause NSHL by affecting protein function. This finding suggests that identifying 2 novel mutations in CDH23 contributes to the genetic basis of NSHL.
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Affiliation(s)
- Jing Sun
- Department of Otolaryngology Head and Neck Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
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2
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Wang P, Miller KK, He E, Dhawan SS, Cunningham CL, Grillet N. LOXHD1 is indispensable for maintaining TMC1 auditory mechanosensitive channels at the site of force transmission. Nat Commun 2024; 15:7865. [PMID: 39256406 PMCID: PMC11387651 DOI: 10.1038/s41467-024-51850-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 08/20/2024] [Indexed: 09/12/2024] Open
Abstract
Hair cell bundles consist of stereocilia arranged in rows of increasing heights, connected by tip links that transmit sound-induced forces to shorter stereocilia tips. Auditory mechanotransduction channel complexes, composed of proteins TMC1/2, TMIE, CIB2, and LHFPL5, are located at the tips of shorter stereocilia. While most components can interact with the tip link in vitro, their ability to maintain the channel complexes at the tip link in vivo is uncertain. Return, using mouse models, we show that an additional component, LOXHD1, is essential for keeping TMC1-pore forming subunits at the tip link but is dispensable for TMC2. Using SUB-immunogold-SEM, we showed that TMC1 localizes near the tip link but mislocalizes without LOXHD1. LOXHD1 selectively interacts with TMC1, CIB2, LHFPL5, and tip-link protein PCDH15. Our results demonstrate that TMC1-driven mature auditory channels require LOXHD1 to stay connected to the tip link and remain functional, while TMC2-driven developmental channels do not.
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Affiliation(s)
- Pei Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Katharine K Miller
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Enqi He
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Siddhant S Dhawan
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA
| | - Christopher L Cunningham
- Pittsburgh Hearing Research Center, Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, 15213, USA
| | - Nicolas Grillet
- Department of Otolaryngology-Head and Neck Surgery, Stanford University, 240 Pasteur Drive, Stanford, CA, USA.
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3
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Hussain S, Sedlacek M, Cui R, Zhang-Hooks W, Bergles D, Bum-Shin J, Kindt KS, Kachar B. Spontaneous calcium transients in hair cell stereocilia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.12.607658. [PMID: 39185174 PMCID: PMC11343103 DOI: 10.1101/2024.08.12.607658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
The hair bundle of auditory and vestibular hair cells converts mechanical stimuli into electrical signals through mechanoelectrical transduction (MET). The MET apparatus is built around a tip link that connects neighboring stereocilia that are aligned in the direction of mechanosensitivity of the hair bundle. Upon stimulation, the MET channel complex responds to changes in tip-link tension and allows a cation influx into the cell. Ca2+ influx in stereocilia has been used as a signature of MET activity. Using genetically encoded Ca2+ sensors (GCaMP3, GCaMP6s) and high-performance fluorescence confocal microscopy, we detect spontaneous Ca2+ transients in individual stereocilia in developing and fully formed hair bundles. We demonstrate that this activity is abolished by MET channel blockers and thus likely originates from putative MET channels. We observe Ca2+ transients in the stereocilia of mice in tissue explants as well as in vivo in zebrafish hair cells, indicating this activity is functionally conserved. Within stereocilia, the origin of Ca2+ transients is not limited to the canonical MET site at the stereocilia tip but is also present along the stereocilia length. Remarkably, we also observe these Ca2+ transients in the microvilli-like structures on the hair cell surface in the early stages of bundle development, prior to the onset of MET. Ca2+ transients are also present in the tallest rows of stereocilia in auditory hair cells, structures not traditionally thought to contain MET channels. We hypothesize that this newly described activity may reflect stochastic and spontaneous MET channel opening. Localization of these transients to other regions of the stereocilia indicates the presence of a pool of channels or channel precursors. Our work provides insights into MET channel assembly, maturation, function, and turnover.
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Affiliation(s)
- Saman Hussain
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Miloslav Sedlacek
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Runjia Cui
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wendy Zhang-Hooks
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Dwight Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Otolaryngology-Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jung Bum-Shin
- Department of Neuroscience, University of Virginia, Charlottesville, VA 22908
| | - Katie S. Kindt
- Laboratory of Cellular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bechara Kachar
- Laboratory of Cell Structure and Dynamics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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4
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Giese APJ, Weng WH, Kindt KS, Chang HHV, Montgomery JS, Ratzan EM, Beirl AJ, Rivera RA, Lotthammer JM, Walujkar S, Foster MP, Zobeiri OA, Holt JR, Riazuddin S, Cullen KE, Sotomayor M, Ahmed ZM. Complexes of vertebrate TMC1/2 and CIB2/3 proteins form hair-cell mechanotransduction cation channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.26.542533. [PMID: 37398045 PMCID: PMC10312449 DOI: 10.1101/2023.05.26.542533] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Calcium and integrin-binding protein 2 (CIB2) and CIB3 bind to transmembrane channel-like 1 (TMC1) and TMC2, the pore-forming subunits of the inner-ear mechano-electrical transduction (MET) apparatus. These interactions have been proposed to be functionally relevant across mechanosensory organs and vertebrate species. Here we show that both CIB2 and CIB3 can form heteromeric complexes with TMC1 and TMC2 and are integral for MET function in mouse cochlea and vestibular end organs as well as in zebrafish inner ear and lateral line. Our AlphaFold 2 models suggest that vertebrate CIB proteins can simultaneously interact with at least two cytoplasmic domains of TMC1 and TMC2 as validated using nuclear magnetic resonance spectroscopy of TMC1 fragments interacting with CIB2 and CIB3. Molecular dynamics simulations of TMC1/2 complexes with CIB2/3 predict that TMCs are structurally stabilized by CIB proteins to form cation channels. Overall, our work demonstrates that intact CIB2/3 and TMC1/2 complexes are integral to hair-cell MET function in vertebrate mechanosensory epithelia.
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Affiliation(s)
- Arnaud P J Giese
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Wei-Hsiang Weng
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Katie S Kindt
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | | | - Jonathan S Montgomery
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Evan M Ratzan
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alisha J Beirl
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Roberto Aponte Rivera
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA
| | - Jeffrey M Lotthammer
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Sanket Walujkar
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Mark P Foster
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Omid A Zobeiri
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Jeffrey R Holt
- Departments of Otolaryngology and Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kathleen E Cullen
- Departments of Biomedical Engineering, Neuroscience, and Otolaryngology and Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
- Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
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5
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de Guimaraes TAC, Robson AG, de Guimaraes IMC, Laich Y, Aychoua N, Wright G, Kalitzeos A, Mahroo OA, Webster AR, Michaelides M. CDH23-Associated Usher Syndrome: Clinical Features, Retinal Imaging, and Natural History. Invest Ophthalmol Vis Sci 2024; 65:27. [PMID: 39017633 PMCID: PMC11262472 DOI: 10.1167/iovs.65.8.27] [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: 02/07/2024] [Accepted: 06/12/2024] [Indexed: 07/18/2024] Open
Abstract
Purpose The purpose of this study was to analyze the clinical spectrum and natural history of CDH23-associated Usher syndrome type ID (USH1D). Methods Molecularly-confirmed individuals had data extracted from medical records. Retinal imaging was extracted from an in-house database. The main outcome measurements were retinal imaging and electroretinography (ERG) and clinical findings, including age of onset, symptoms, best-corrected visual acuity (BCVA), outer nuclear layer (ONL) thickness, ellipsoid zone width (EZW), and hyperautofluorescent ring area. Results Thirty-one patients were identified, harboring 40 variants in CDH23 (10 being novel). The mean (range, ±SD) age of symptom onset was 10.1 years (range = 1-18, SD = ±4.1). The most common visual symptoms at presentation were nyctalopia (93.5%) and peripheral vision difficulties (61.3%). The mean BCVA at baseline was 0.25 ± 0.22 in the right eyes and 0.35 ± 0.58 LogMAR in the left eyes. The mean annual loss rate in BCVA was 0.018 LogMAR/year over a mean follow-up of 9.5 years. Individuals harboring the c.5237G>A p.(Arg1746Gln) allele had retinitis pigmentosa (RP) sparing the superior retina. Seventy-seven percent of patients had hyperautofluorescent rings in fundus autofluorescence. Full-field and pattern ERGs indicated moderate-severe rod-cone or photoreceptor dysfunction with relative sparing of macular function in most patients tested. Optical coherence tomography (OCT) revealed intraretinal cysts in the transfoveal B-scan of 13 individuals (43.3%). The rate of EZW and ONL thickness loss was mild and suggestive of a wide window of macular preservation. Conclusions Despite the early onset of symptoms, USH1D has a slowly progressive phenotype. There is high interocular symmetry across all parameters, making it an attractive target for novel therapies.
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Affiliation(s)
- Thales A. C. de Guimaraes
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Anthony G. Robson
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | | | - Yannik Laich
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Eye Center, Faculty of Medicine, University Freiburg, Germany
| | - Nancy Aychoua
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Genevieve Wright
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Omar A. Mahroo
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew R. Webster
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
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6
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Pedro De-la-Torre, Wen H, Brower J, Martínez-Pérez K, Narui Y, Yeh F, Hale E, Ivanchenko MV, Corey DP, Sotomayor M, Indzhykulian AA. Elasticity and Thermal Stability are Key Determinants of Hearing Rescue by Mini-Protocadherin-15 Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.16.599132. [PMID: 38948700 PMCID: PMC11212938 DOI: 10.1101/2024.06.16.599132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Protocadherin-15 is a core protein component of inner-ear hair-cell tip links pulling on transduction channels essential for hearing and balance. Protocadherin-15 defects can result in non-syndromic deafness or Usher syndrome type 1F (USH1F) with hearing loss, balance deficits, and progressive blindness. Three rationally engineered shortened versions of protocadherin-15 (mini-PCDH15s) amenable for gene therapy have been used to rescue function in USH1F mouse models. Two can successfully or partially rescue hearing, while another one fails. Here we show that despite varying levels of hearing rescue, all three mini-PCDH15 versions can rescue hair-cell mechanotransduction. Negative-stain electron microscopy shows that all three versions form dimers like the wild-type protein, while crystal structures of some engineered fragments show that these can properly fold and bind calcium ions essential for function. In contrast, simulations predict distinct elasticities and nano differential scanning fluorimetry shows differences in melting temperature measurements. Our data suggest that elasticity and thermal stability are key determinants of sustained hearing rescue by mini-PCDH15s.
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Affiliation(s)
- Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Haosheng Wen
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
- Biophysics Program, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
| | - Joseph Brower
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Karina Martínez-Pérez
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Biology Program, Department of Basic Sciences, Universidad del Atlántico, Cra 30 # 8-49, Puerto Colombia, 081007, Colombia
| | - Yoshie Narui
- Center for Electron Microscopy and Analysis, The Ohio State University, 1275-1305 Kinnear Road, Columbus, OH, USA
| | - Frank Yeh
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Evan Hale
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Speech and Hearing Biosciences and Technology graduate program, Harvard University, Cambridge, MA, USA
| | - Maryna V. Ivanchenko
- Department of Neurobiology, Harvard Medical School, 200 Longwood Ave, Boston, MA, USA
| | - David P. Corey
- Department of Neurobiology, Harvard Medical School, 200 Longwood Ave, Boston, MA, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
- Biophysics Program, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
| | - Artur A. Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Speech and Hearing Biosciences and Technology graduate program, Harvard University, Cambridge, MA, USA
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7
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De-la-Torre P, Martínez-García C, Gratias P, Mun M, Santana P, Akyuz N, González W, Indzhykulian AA, Ramírez D. Identification of Druggable Binding Sites and Small Molecules as Modulators of TMC1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.05.583611. [PMID: 38826329 PMCID: PMC11142246 DOI: 10.1101/2024.03.05.583611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Our ability to hear and maintain balance relies on the proper functioning of inner ear sensory hair cells, which translate mechanical stimuli into electrical signals via mechano-electrical transducer (MET) channels, composed of TMC1/2 proteins. However, the therapeutic use of ototoxic drugs, such as aminoglycosides and cisplatin, which can enter hair cells through MET channels, often leads to profound auditory and vestibular dysfunction. Despite extensive research on otoprotective compounds targeting MET channels, our understanding of how small molecule modulators interact with these channels remains limited, hampering the discovery of novel compounds. Here, we propose a structure-based screening approach, integrating 3D-pharmacophore modeling, molecular simulations, and experimental validation. Our pipeline successfully identified several novel compounds and FDA-approved drugs that reduced dye uptake in cultured cochlear explants, indicating MET modulation activity. Molecular docking and free-energy estimations for binding allowed us to identify three potential drug binding sites within the channel pore, phospholipids, and key amino acids involved in modulator interactions. We also identified shared ligand-binding features between TMC and structurally related TMEM16 protein families, providing novel insights into their distinct inhibition, while potentially guiding the rational design of MET-channel-specific modulators. Our pipeline offers a broad application to discover small molecule modulators for a wide spectrum of mechanosensitive ion channels.
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Affiliation(s)
- Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | | | - Paul Gratias
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | - Matthew Mun
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | - Paula Santana
- Facultad de Ingeniería, Instituto de Ciencias Químicas Aplicadas, Universidad Autónoma de Chile, Santiago, Chile
| | - Nurunisa Akyuz
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Wendy González
- Center for Bioinformatics and Molecular Simulations (CBSM), University of Talca, Talca 3460000, Chile
| | - Artur A. Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Mass Eye and Ear, Boston, MA, USA
| | - David Ramírez
- Department of Pharmacology, Faculty of Biological Sciences, University of Concepción, Chile
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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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Neuhofer CM, Prokisch H. Digenic Inheritance in Rare Disorders and Mitochondrial Disease-Crossing the Frontier to a More Comprehensive Understanding of Etiology. Int J Mol Sci 2024; 25:4602. [PMID: 38731822 PMCID: PMC11083678 DOI: 10.3390/ijms25094602] [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: 02/13/2024] [Revised: 04/10/2024] [Accepted: 04/12/2024] [Indexed: 05/13/2024] Open
Abstract
Our understanding of rare disease genetics has been shaped by a monogenic disease model. While the traditional monogenic disease model has been successful in identifying numerous disease-associated genes and significantly enlarged our knowledge in the field of human genetics, it has limitations in explaining phenomena like phenotypic variability and reduced penetrance. Widening the perspective beyond Mendelian inheritance has the potential to enable a better understanding of disease complexity in rare disorders. Digenic inheritance is the simplest instance of a non-Mendelian disorder, characterized by the functional interplay of variants in two disease-contributing genes. Known digenic disease causes show a range of pathomechanisms underlying digenic interplay, including direct and indirect gene product interactions as well as epigenetic modifications. This review aims to systematically explore the background of digenic inheritance in rare disorders, the approaches and challenges when investigating digenic inheritance, and the current evidence for digenic inheritance in mitochondrial disorders.
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Affiliation(s)
- Christiane M. Neuhofer
- Institute of Human Genetics, University Medical Center, Technical University of Munich, Trogerstr. 32, 81675 Munich, Germany
- Institute of Neurogenomics, Computational Health Center, Helmholtz Centre Munich Neuherberg, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany
- Institute of Human Genetics, Salzburger Landeskliniken, University Hospital of the Paracelsus Medical University, Müllner Hauptstraße 48, 5020 Salzburg, Austria
| | - Holger Prokisch
- Institute of Human Genetics, University Medical Center, Technical University of Munich, Trogerstr. 32, 81675 Munich, Germany
- Institute of Neurogenomics, Computational Health Center, Helmholtz Centre Munich Neuherberg, Ingolstädter Landstraße 1, 85764 Oberschleißheim, Germany
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Datta P, Rhee KD, Staudt RJ, Thompson JM, Hsu Y, Hassan S, Drack AV, Seo S. Delivering large genes using adeno-associated virus and the CRE-lox DNA recombination system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588864. [PMID: 38645107 PMCID: PMC11030439 DOI: 10.1101/2024.04.10.588864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Adeno-associated virus (AAV) is a safe and efficient gene delivery vehicle for gene therapies. However, its relatively small packaging capacity limits its use as a gene transfer vector. Here, we describe a strategy to deliver large genes that exceed the AAV's packaging capacity using up to four AAV vectors and the CRE-lox DNA recombination system. We devised novel lox sites by combining non-compatible and reaction equilibrium-modifying lox site variants. These lox sites facilitate sequence-specific and near-unidirectional recombination of AAV vector genomes, enabling efficient reconstitution of up to 16 kb of therapeutic genes in a pre-determined configuration. Using this strategy, we have developed AAV gene therapy vectors to deliver IFT140 , PCDH15 , CEP290 , and CDH23 and demonstrate efficient production of full-length proteins in cultured mammalian cells and mouse retinas. Notably, this approach significantly surpasses the trans-splicing and split-intein-based reconstitution methods in efficiency, requiring lower doses, minimizing or eliminating the production of truncated protein products, and offering flexibility in selecting splitting positions. The CRE-lox approach described here provides a simple and effective platform for producing AAV gene therapy vectors beyond AAV's packaging capacity.
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11
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Jiao J, Yu S, Gu G, Chen G, Zhang H, Zheng Y. Variations in the Cadherin 23 Gene Associated With Noise-Induced Hearing Loss. J Multidiscip Healthc 2024; 17:1473-1482. [PMID: 38605856 PMCID: PMC11007390 DOI: 10.2147/jmdh.s453417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 03/11/2024] [Indexed: 04/13/2024] Open
Abstract
Background The relationship between CDH23 gene variants and NIHL is unclear. This study investigates the association between cadherin 23 (CDH23) gene variants and noise-induced hearing loss (NIHL). Methods This is a case-control study. Workers who were exposed to noise from a steel factory in North China were recruited and divided into two groups: the case group (both ears' high-frequency threshold average [BHFTA] ≥40dB) and the control group (BHFTA ≤25 dB). This study used the generalised multifactor dimensionality reduction method to analyse the association among 18 single-nucleotide polymorphisms (SNPs) in CDH23 and NIHL. Logistic regression was performed to investigate the main effects of SNPs and the interactions between cumulative noise exposure (CNE) and SNPs. Furthermore, CNE was adjusted for age, gender, smoking, drinking, physical exercise and hypertension. Results This study recruited 1,117 participants. The results showed that for rs11592462, participants who carried the GG genotype showed an association with NIHL greater than that of those who carried the CC genotype. Accordingly, genetic variation in the CDH23 gene could play an essential role in determining individual susceptibility to NIHL. Conclusion Genetic variations in the CDH23 gene may play an important role in determining individual susceptibility to NIHL. These results provide new insight into the pathogenesis and early prevention of NIHL.
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Affiliation(s)
- Jie Jiao
- The Third People’s Hospital of Henan Province (Henan Hospital for Occupational Diseases), Zhengzhou, Henan, People’s Republic of China
| | - Shanfa Yu
- Henan Medical College, Zhengzhou, Henan, People’s Republic of China
| | - Guizhen Gu
- The Third People’s Hospital of Henan Province (Henan Hospital for Occupational Diseases), Zhengzhou, Henan, People’s Republic of China
| | - Guoshun Chen
- Wugang Institute for Occupational Health, Wugang, Henan, People’s Republic of China
| | - Huanling Zhang
- Wugang Institute for Occupational Health, Wugang, Henan, People’s Republic of China
| | - Yuxin Zheng
- School of Public Health, Qingdao University, Qingdao, Shandong, People’s Republic of China
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12
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Strelkova OS, Osgood RT, Tian CJ, Zhang X, Hale E, De-la-Torre P, Hathaway DM, Indzhykulian AA. PKHD1L1 is required for stereocilia bundle maintenance, durable hearing function and resilience to noise exposure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.29.582786. [PMID: 38496629 PMCID: PMC10942330 DOI: 10.1101/2024.02.29.582786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Sensory hair cells of the cochlea are essential for hearing, relying on the mechanosensitive stereocilia bundle at their apical pole for their function. Polycystic Kidney and Hepatic Disease 1-Like 1 (PKHD1L1) is a stereocilia protein required for normal hearing in mice, and for the formation of the transient stereocilia surface coat, expressed during early postnatal development. While the function of the stereocilia coat remains unclear, growing evidence supports PKHD1L1 as a human deafness gene. In this study we carry out in depth characterization of PKHD1L1 expression in mice during development and adulthood, analyze hair-cell bundle morphology and hearing function in aging PKHD1L1-defficient mouse lines, and assess their susceptibility to noise damage. Our findings reveal that PKHD1L1-deficient mice display no disruption to bundle cohesion or tectorial membrane attachment-crown formation during development. However, starting from 6 weeks of age, PKHD1L1-defficient mice display missing stereocilia and disruptions to bundle coherence. Both conditional and constitutive PKHD1L1 knock-out mice develop high-frequency hearing loss progressing to lower frequencies with age. Furthermore, PKHD1L1-deficient mice are susceptible to permanent hearing loss following moderate acoustic overexposure, which induces only temporary hearing threshold shifts in wild-type mice. These results suggest a role for PKHD1L1 in establishing robust sensory hair bundles during development, necessary for maintaining bundle cohesion and function in response to acoustic trauma and aging.
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Affiliation(s)
| | | | | | - Xinyuan Zhang
- Department of Otolaryngology Head and Neck Surgery, Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Evan Hale
- Department of Otolaryngology Head and Neck Surgery, Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Pedro De-la-Torre
- Department of Otolaryngology Head and Neck Surgery, Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Daniel M. Hathaway
- Department of Otolaryngology Head and Neck Surgery, Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
| | - Artur A. Indzhykulian
- Department of Otolaryngology Head and Neck Surgery, Mass Eye and Ear, Harvard Medical School, Boston, MA, United States
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13
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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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14
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Li N, Liu S, Zhao D, Du H, Xi Y, Wei X, Liu Q, Müller U, Lu Q, Xiong W, Xu Z. Disruption of Cdh23 exon 68 splicing leads to progressive hearing loss in mice by affecting tip-link stability. Proc Natl Acad Sci U S A 2024; 121:e2309656121. [PMID: 38408254 PMCID: PMC10927504 DOI: 10.1073/pnas.2309656121] [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: 06/13/2023] [Accepted: 12/21/2023] [Indexed: 02/28/2024] Open
Abstract
Inner ear hair cells are characterized by the F-actin-based stereocilia that are arranged into a staircase-like pattern on the apical surface of each hair cell. The tips of shorter-row stereocilia are connected with the shafts of their neighboring taller-row stereocilia through extracellular links named tip links, which gate mechano-electrical transduction (MET) channels in hair cells. Cadherin 23 (CDH23) forms the upper part of tip links, and its cytoplasmic tail is inserted into the so-called upper tip-link density (UTLD) that contains other proteins such as harmonin. The Cdh23 gene is composed of 69 exons, and we show here that exon 68 is subjected to hair cell-specific alternative splicing. Tip-link formation is not affected in genetically modified mutant mice lacking Cdh23 exon 68. Instead, the stability of tip links is compromised in the mutants, which also suffer from progressive and noise-induced hearing loss. Moreover, we show that the cytoplasmic tail of CDH23(+68) but not CDH23(-68) cooperates with harmonin in phase separation-mediated condensate formation. In conclusion, our work provides evidence that inclusion of Cdh23 exon 68 is critical for the stability of tip links through regulating condensate formation of UTLD components.
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Affiliation(s)
- Nana Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong266237, China
| | - Shuang Liu
- Chinese Institute for Brain Research, Beijing102206, China
| | - Dange Zhao
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai200030, China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong266237, China
| | - Yuehui Xi
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong266237, China
| | - Xiaoxi Wei
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai200030, China
| | - Qingling Liu
- Chinese Institute for Brain Research, Beijing102206, China
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Qing Lu
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai200030, China
| | - Wei Xiong
- Chinese Institute for Brain Research, Beijing102206, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong266237, China
- Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, Shandong250014, China
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15
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Arora N, Hazra JP, Roy S, Bhati GK, Gupta S, Yogendran KP, Chaudhuri A, Sagar A, Rakshit S. Emergence of slip-ideal-slip behavior in tip-links serve as force filters of sound in hearing. Nat Commun 2024; 15:1595. [PMID: 38383683 PMCID: PMC10881517 DOI: 10.1038/s41467-024-45423-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
Tip-links in the inner ear convey force from sound and trigger mechanotransduction. Here, we present evidence that tip-links (collectively as heterotetrameric complexes of cadherins) function as force filters during mechanotransduction. Our force-clamp experiments reveal that the tip-link complexes show slip-ideal-slip bond dynamics. At low forces, the lifetime of the tip-link complex drops monotonically, indicating slip-bond dynamics. The ideal bond, rare in nature, is seen in an intermediate force regime where the survival of the complex remains constant over a wide range. At large forces, tip-links follow a slip bond and dissociate entirely to cut-off force transmission. In contrast, the individual tip-links (heterodimers) display slip-catch-slip bonds to the applied forces. While with a phenotypic mutant, we showed the importance of the slip-catch-slip bonds in uninterrupted hearing, our coarse-grained Langevin dynamics simulations demonstrated that the slip-ideal-slip bonds emerge as a collective feature from the slip-catch-slip bonds of individual tip-links.
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Affiliation(s)
- Nisha Arora
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Jagadish P Hazra
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Sandip Roy
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Gaurav K Bhati
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Sarika Gupta
- National Institute of Immunology, New Delhi, India
| | - K P Yogendran
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Abhishek Chaudhuri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
| | - Amin Sagar
- Centre de Biologie Structurale, INSERM, CNRS, Université de Montpellier, Montpellier, France.
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India.
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16
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Clark S, Jeong H, Posert R, Goehring A, Gouaux E. The structure of the Caenorhabditis elegans TMC-2 complex suggests roles of lipid-mediated subunit contacts in mechanosensory transduction. Proc Natl Acad Sci U S A 2024; 121:e2314096121. [PMID: 38354260 PMCID: PMC10895266 DOI: 10.1073/pnas.2314096121] [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: 08/15/2023] [Accepted: 12/21/2023] [Indexed: 02/16/2024] Open
Abstract
Mechanotransduction is the process by which a mechanical force, such as touch, is converted into an electrical signal. Transmembrane channel-like (TMC) proteins are an evolutionarily conserved family of membrane proteins whose function has been linked to a variety of mechanosensory processes, including hearing and balance sensation in vertebrates and locomotion in Drosophila. TMC1 and TMC2 are components of ion channel complexes, but the molecular features that tune these complexes to diverse mechanical stimuli are unknown. Caenorhabditis elegans express two TMC homologs, TMC-1 and TMC-2, both of which are the likely pore-forming subunits of mechanosensitive ion channels but differ in their expression pattern and functional role in the worm. Here, we present the single-particle cryo-electron microscopy structure of the native TMC-2 complex isolated from C. elegans. The complex is composed of two copies of the pore-forming TMC-2 subunit, the calcium and integrin binding protein CALM-1 and the transmembrane inner ear protein TMIE. Comparison of the TMC-2 complex to the recently published cryo-EM structure of the C. elegans TMC-1 complex highlights conserved protein-lipid interactions, as well as a π-helical structural motif in the pore-forming helices, that together suggest a mechanism for TMC-mediated mechanosensory transduction.
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Affiliation(s)
- Sarah Clark
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - Hanbin Jeong
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - Rich Posert
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
| | - April Goehring
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
- HHMI, Oregon Health and Science University, Portland, OR97239
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, OR97239
- HHMI, Oregon Health and Science University, Portland, OR97239
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17
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Lee JH, Perez-Flores MC, Park S, Kim HJ, Chen Y, Kang M, Kersigo J, Choi J, Thai PN, Woltz RL, Perez-Flores DC, Perkins G, Sihn CR, Trinh P, Zhang XD, Sirish P, Dong Y, Feng WW, Pessah IN, Dixon RE, Sokolowski B, Fritzsch B, Chiamvimonvat N, Yamoah EN. The Piezo channel is a mechano-sensitive complex component in the mammalian inner ear hair cell. Nat Commun 2024; 15:526. [PMID: 38228630 PMCID: PMC10791687 DOI: 10.1038/s41467-023-44230-x] [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: 07/02/2023] [Accepted: 12/04/2023] [Indexed: 01/18/2024] Open
Abstract
The inner ear is the hub where hair cells (HCs) transduce sound, gravity, and head acceleration stimuli to the brain. Hearing and balance rely on mechanosensation, the fastest sensory signals transmitted to the brain. The mechanoelectrical transducer (MET) channel is the entryway for the sound-balance-brain interface, but the channel-complex composition is not entirely known. Here, we report that the mouse utilizes Piezo1 (Pz1) and Piezo2 (Pz2) isoforms as MET-complex components. The Pz channels, expressed in HC stereocilia, and cell lines are co-localized and co-assembled with MET complex partners. Mice expressing non-functional Pz1 and Pz2 at the ROSA26 locus have impaired auditory and vestibular traits that can only be explained if the Pzs are integral to the MET complex. We suggest that Pz subunits constitute part of the MET complex and that interactions with other MET complex components yield functional MET units to generate HC MET currents.
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Affiliation(s)
- Jeong Han Lee
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Maria C Perez-Flores
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Seojin Park
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
- Prestige Biopharma, 11-12F, 44, Myongjigukje7-ro, Gangseo-gu, Busan, 67264, South Korea
| | - Hyo Jeong Kim
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Yingying Chen
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Mincheol Kang
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
- Prestige Biopharma, 11-12F, 44, Myongjigukje7-ro, Gangseo-gu, Busan, 67264, South Korea
| | | | - Jinsil Choi
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Phung N Thai
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Ryan L Woltz
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | | | - Guy Perkins
- National Center for Microscopy and Imaging Research, University of California San Diego, La Jolla, CA, 92093, USA
| | - Choong-Ryoul Sihn
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA
| | - Pauline Trinh
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Padmini Sirish
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Yao Dong
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 VM3B, Davis, CA, 95616, USA
| | - Wayne Wei Feng
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 VM3B, Davis, CA, 95616, USA
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 VM3B, Davis, CA, 95616, USA
| | - Rose E Dixon
- Department of Physiology & Membrane Biology, Tupper Hall, One Shields Avenue, Davis, CA, 95616, USA
| | - Bernd Sokolowski
- Department of Otolaryngology-Head and Neck Surgery, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
- VA Northern California Healthcare System, Sacramento, USA
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, 89557, USA.
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18
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Beurg M, Schwalbach ET, Fettiplace R. LHFPL5 is a key element in force transmission from the tip link to the hair cell mechanotransducer channel. Proc Natl Acad Sci U S A 2024; 121:e2318270121. [PMID: 38194445 PMCID: PMC10801851 DOI: 10.1073/pnas.2318270121] [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: 10/19/2023] [Accepted: 11/30/2023] [Indexed: 01/11/2024] Open
Abstract
During auditory transduction, sound-evoked vibrations of the hair cell stereociliary bundles open mechanotransducer (MET) ion channels via tip links extending from one stereocilium to its neighbor. How tension in the tip link is delivered to the channel is not fully understood. The MET channel comprises a pore-forming subunit, transmembrane channel-like protein (TMC1 or TMC2), aided by several accessory proteins, including LHFPL5 (lipoma HMGIC fusion partner-like 5). We investigated the role of LHFPL5 in transduction by comparing MET channel activation in outer hair cells of Lhfpl5-/- knockout mice with those in Lhfpl5+/- heterozygotes. The 10 to 90 percent working range of transduction in Tmc1+/+; Lhfpl5+/- was 52 nm, from which the single-channel gating force, Z, was evaluated as 0.34 pN. However, in Tmc1+/+; Lhfpl5-/- mice, the working range increased to 123 nm and Z more than halved to 0.13 pN, indicating reduced sensitivity. Tip link tension is thought to activate the channel via a gating spring, whose stiffness is inferred from the stiffness change on tip link destruction. The gating stiffness was ~40 percent of the total bundle stiffness in wild type but was virtually abolished in Lhfpl5-/-, implicating LHFPL5 as a principal component of the gating spring. The mutation Tmc1 p.D569N reduced the LHFPL5 immunolabeling in the stereocilia and like Lhfpl5-/- doubled the MET working range, but other deafness mutations had no effect on the dynamic range. We conclude that tip-link tension is transmitted to the channel primarily via LHFPL5; residual activation without LHFPL5 may occur by direct interaction between PCDH15 and TMC1.
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Affiliation(s)
- Maryline Beurg
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
| | - Evan Travis Schwalbach
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
| | - Robert Fettiplace
- Department of Neuroscience, University of WisconsinSchool of Medicine and Public Health, Madison, WI53706
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19
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Warren B, Eberl D. What can insects teach us about hearing loss? J Physiol 2024; 602:297-316. [PMID: 38128023 DOI: 10.1113/jp281281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Over the last three decades, insects have been utilized to provide a deep and fundamental understanding of many human diseases and disorders. Here, we present arguments for insects as models to understand general principles underlying hearing loss. Despite ∼600 million years since the last common ancestor of vertebrates and invertebrates, we share an overwhelming degree of genetic homology particularly with respect to auditory organ development and maintenance. Despite the anatomical differences between human and insect auditory organs, both share physiological principles of operation. We explain why these observations are expected and highlight areas in hearing loss research in which insects can provide insight. We start by briefly introducing the evolutionary journey of auditory organs, the reasons for using insect auditory organs for hearing loss research, and the tools and approaches available in insects. Then, the first half of the review focuses on auditory development and auditory disorders with a genetic cause. The second half analyses the physiological and genetic consequences of ageing and short- and long-term changes as a result of noise exposure. We finish with complex age and noise interactions in auditory systems. In this review, we present some of the evidence and arguments to support the use of insects to study mechanisms and potential treatments for hearing loss in humans. Obviously, insects cannot fully substitute for all aspects of human auditory function and loss of function, although there are many important questions that can be addressed in an animal model for which there are important ethical, practical and experimental advantages.
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Affiliation(s)
- Ben Warren
- Neurogenetics Group, College of Life Sciences, University of Leicester, Leicester, UK
| | - Daniel Eberl
- Department of Biology, University of Iowa, Iowa City, IA, USA
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20
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Chess MM, Douglas W, Saunders J, Ettensohn CA. Genome-wide identification and spatiotemporal expression analysis of cadherin superfamily members in echinoderms. EvoDevo 2023; 14:15. [PMID: 38124068 PMCID: PMC10734073 DOI: 10.1186/s13227-023-00219-7] [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: 10/09/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Cadherins are calcium-dependent transmembrane cell-cell adhesion proteins that are essential for metazoan development. They consist of three subfamilies: classical cadherins, which bind catenin, protocadherins, which contain 6-7 calcium-binding repeat domains, and atypical cadherins. Their functions include forming adherens junctions, establishing planar cell polarity (PCP), and regulating cell shape, proliferation, and migration. Because they are basal deuterostomes, echinoderms provide important insights into bilaterian evolution, but their only well-characterized cadherin is G-cadherin, a classical cadherin that is expressed by many embryonic epithelia. We aimed to better characterize echinoderm cadherins by conducting phylogenetic analyses and examining the spatiotemporal expression patterns of cadherin-encoding genes during Strongylocentrotus purpuratus development. RESULTS Our phylogenetic analyses conducted on two echinoid, three asteroid, and one crinoid species identified ten echinoderm cadherins, including one deuterostome-specific ortholog, cadherin-23, and an echinoderm-specific atypical cadherin that possibly arose in an echinoid-asteroid ancestor. Catenin-binding domains in dachsous-2 orthologs were found to be a deuterostome-specific innovation that was selectively lost in mouse, while those in Fat4 orthologs appeared to be Ambulacraria-specific and were selectively lost in non-crinoid echinoderms. The identified suite of echinoderm cadherins lacks vertebrate-specific innovations but contains two proteins that are present in protostomes and absent from mouse. The spatiotemporal expression patterns of four embryonically expressed cadherins (fat atypical cadherins 1 and 4, dachsous-2, and protocadherin-9) were dynamic and mirrored the expression pattern of Frizzled 5/8, a non-canonical Wnt PCP pathway receptor protein essential for archenteron morphogenesis. CONCLUSIONS The echinoderm cadherin toolkit is more similar to that of an ancient bilaterian predating protostomes and deuterostomes than it is to the suite of cadherins found in extant vertebrates. However, it also appears that deuterostomes underwent several cadherin-related innovations. Based on their similar spatiotemporal expression patterns and orthologous relationships to PCP-related and tumor-suppressing proteins, we hypothesize that sea urchin cadherins may play a role in regulating the shape and growth of embryonic epithelia and organs. Future experiments will examine cadherin expression in non-echinoid echinoderms and explore the functions of cadherins during echinoderm development.
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Affiliation(s)
- Macie M Chess
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - William Douglas
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Josiah Saunders
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Charles A Ettensohn
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
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21
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Clark S, Mitra J, Elferich J, Goehring A, Ge J, Ha T, Gouaux E. Single molecule studies of the native hair cell mechanosensory transduction complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.11.571162. [PMID: 38168376 PMCID: PMC10760052 DOI: 10.1101/2023.12.11.571162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Hearing and balance rely on the conversion of a mechanical stimulus into an electrical signal, a process known as mechanosensory transduction (MT). In vertebrates, this process is accomplished by an MT complex that is located in hair cells of the inner ear. While the past three decades of research have identified many subunits that are important for MT and revealed interactions between these subunits, the composition and organization of a functional complex remains unknown. The major challenge associated with studying the MT complex is its extremely low abundance in hair cells; current estimates of MT complex quantity range from 3-60 attomoles per cochlea or utricle, well below the detection limit of most biochemical assays that are used to characterize macromolecular complexes. Here we describe the optimization of two single molecule assays, single molecule pull-down (SiMPull) and single molecule array (SiMoA), to study the composition and quantity of native mouse MT complexes. We demonstrate that these assays are capable of detecting and quantifying low attomoles of the native MT subunits protocadherin-15 (PCDH15) and lipoma HMGIC fusion partner-like protein 5 (LHFPL5). Our results illuminate the stoichiometry of PCDH15- and LHFPL5-containing complexes and establish SiMPull and SiMoA as productive methods for probing the abundance, composition, and arrangement of subunits in the native MT complex.
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Affiliation(s)
- Sarah Clark
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Present address: Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | - Jaba Mitra
- Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, IL 61801, USA
- Present address: Pacific Biosciences, Menlo Park, CA 94025, USA
| | - Johannes Elferich
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Present address: UMass Chan Medical School, Worcester, MA 01655, USA
| | - April Goehring
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Jingpeng Ge
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Present address: School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, 201210, China
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, MD 21215, USA
- Present address: Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Present address: Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
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22
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Ivanchenko MV, Hathaway DM, Mulhall EM, Booth KT, Wang M, Peters CW, Klein AJ, Chen X, Li Y, György B, Corey DP. PCDH15 Dual-AAV Gene Therapy for Deafness and Blindness in Usher Syndrome Type 1F. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566447. [PMID: 38014037 PMCID: PMC10680673 DOI: 10.1101/2023.11.09.566447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Usher syndrome type 1F (USH1F), resulting from mutations in the protocadherin-15 (PCDH15) gene, is characterized by congenital lack of hearing and balance, and progressive blindness in the form of retinitis pigmentosa. In this study, we explore a novel approach for USH1F gene therapy, exceeding the single AAV packaging limit by employing a dual adeno-associated virus (AAV) strategy to deliver the full-length PCDH15 coding sequence. We demonstrate the efficacy of this strategy in mouse USH1F models, effectively restoring hearing and balance in these mice. Importantly, our approach also proves successful in expressing PCDH15 in clinically relevant retinal models, including human retinal organoids and non-human primate retina, showing efficient targeting of photoreceptors and proper protein expression in the calyceal processes. This research represents a major step toward advancing gene therapy for USH1F and the multiple challenges of hearing, balance, and vision impairment.
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23
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Newton S, Aguilar C, Bunton-Stasyshyn RK, Flook M, Stewart M, Marcotti W, Brown S, Bowl MR. Absence of Embigin accelerates hearing loss and causes sub-viability, brain and heart defects in C57BL/6N mice due to interaction with Cdh23ahl. iScience 2023; 26:108056. [PMID: 37854703 PMCID: PMC10579432 DOI: 10.1016/j.isci.2023.108056] [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: 06/05/2023] [Revised: 08/08/2023] [Accepted: 09/22/2023] [Indexed: 10/20/2023] Open
Abstract
Mouse studies continue to help elaborate upon the genetic landscape of mammalian disease and the underlying molecular mechanisms. Here, we have investigated an Embigintm1b allele maintained on a standard C57BL/6N background and on a co-isogenic C57BL/6N background in which the Cdh23ahl allele has been "repaired." The hypomorphic Cdh23ahl allele is present in several commonly used inbred mouse strains, predisposing them to progressive hearing loss, starting in high-frequency regions. Absence of the neural cell adhesion molecule Embigin on the standard C57BL/6N background leads to accelerated hearing loss and causes sub-viability, brain and cardiac defects. Contrastingly, Embigintm1b/tm1b mice maintained on the co-isogenic "repaired" C57BL/6N background exhibit normal hearing and viability. Thus Embigin genetically interacts with Cdh23. Importantly, our study is the first to demonstrate an effect of the common Cdh23ahl allele outside of the auditory system, which has important ramifications for genetic studies involving inbred strains carrying this allele.
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Affiliation(s)
- Sherylanne Newton
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Oxford, Oxfordshire OX11 0RD, UK
- UCL Ear Institute, University College London, 332 Gray’s Inn Road, London WC1X 8EE, UK
| | - Carlos Aguilar
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Oxford, Oxfordshire OX11 0RD, UK
- UCL Ear Institute, University College London, 332 Gray’s Inn Road, London WC1X 8EE, UK
| | | | - Marisa Flook
- UCL Ear Institute, University College London, 332 Gray’s Inn Road, London WC1X 8EE, UK
| | - Michelle Stewart
- The Mary Lyon Centre, Medical Research Council Harwell Institute, Oxford, Oxfordshire OX11 0RD, UK
| | - Walter Marcotti
- School of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
- Sheffield Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Steve Brown
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Oxford, Oxfordshire OX11 0RD, UK
| | - Michael R. Bowl
- Mammalian Genetics Unit, Medical Research Council Harwell Institute, Harwell Oxford, Oxfordshire OX11 0RD, UK
- UCL Ear Institute, University College London, 332 Gray’s Inn Road, London WC1X 8EE, UK
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24
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Villasante CM, Deng X, Cohen JE, Hudspeth AJ. Nanomechanics of wild-type and mutant dimers of the tip-link protein protocadherin 15. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.562769. [PMID: 37905108 PMCID: PMC10614884 DOI: 10.1101/2023.10.17.562769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Mechanical force controls the opening and closing of mechanosensitive ion channels atop the hair bundles of the inner ear. The filamentous tip link connecting transduction channels to the tallest neighboring stereocilium modulates the force transmitted to the channels and thus changes their probability of opening. Each tip link comprises four molecules: a dimer of protocadherin 15 and a dimer of cadherin 23, all of which are stabilized by Ca2+ binding. Using a high-speed optical trap to examine dimeric PCDH15, we find that the protein's configuration is sensitive to Ca2+ and that the molecule exhibits limited unfolding at a physiological Ca2+ concentration. PCDH15 can therefore modulate its stiffness without undergoing large unfolding events in physiological Ca2+ conditions. The experimentally determined stiffness of PCDH15 accords with published values for the stiffness of the gating spring, the mechanical element that controls the opening of mechanotransduction channels. When PCDH15 has a point mutation, V507D, associated with non-syndromic hearing loss, unfolding events occur more frequently under tension and refolding events occur less often than in the wild-type protein. Our results suggest that the maintenance of appropriate tension in the gating spring is critical to the appropriate transmission of force to transduction channels, and hence to hearing.
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Affiliation(s)
- Camila M Villasante
- Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10065 USA
| | - Xinyue Deng
- Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10065 USA
| | - Joel E Cohen
- Laboratory of Populations, The Rockefeller University, New York, NY 10065 USA
- Earth Institute and Department of Statistics, Columbia University, New York, NY 10027 USA
- Department of Statistics, University of Chicago, Chicago, IL 60637 USA
| | - A J Hudspeth
- Laboratory of Sensory Neuroscience, The Rockefeller University, New York, NY 10065 USA
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065 USA
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25
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Hool SA, Jeng J, Jagger DJ, Marcotti W, Ceriani F. Age-related changes in P2Y receptor signalling in mouse cochlear supporting cells. J Physiol 2023; 601:4375-4395. [PMID: 37715703 PMCID: PMC10952729 DOI: 10.1113/jp284980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/16/2023] [Indexed: 09/18/2023] Open
Abstract
Our sense of hearing depends on the function of a specialised class of sensory cells, the hair cells, which are found in the organ of Corti of the mammalian cochlea. The unique physiological environment in which these cells operate is maintained by a syncitium of non-sensory supporting cells, which are crucial for regulating cochlear physiology and metabolic homeostasis. Despite their importance for cochlear function, the role of these supporting cells in age-related hearing loss, the most common sensory deficit in the elderly, is poorly understood. Here, we investigated the age-related changes in the expression and function of metabotropic purinergic receptors (P2Y1 , P2Y2 and P2Y4 ) in the supporting cells of the cochlear apical coil. Purinergic signalling in supporting cells is crucial during the development of the organ of Corti and purinergic receptors are known to undergo changes in expression during ageing in several tissues. Immunolabelling and Ca2+ imaging experiments revealed a downregulation of P2Y receptor expression and a decrease of purinergic-mediated calcium responses after early postnatal stages in the supporting cells. An upregulation of P2Y receptor expression was observed in the aged cochlea when compared to 1 month-old adults. The aged mice also had significantly larger calcium responses and displayed calcium oscillations during prolonged agonist applications. We conclude that supporting cells in the aged cochlea upregulate P2Y2 and P2Y4 receptors and display purinergic-induced Ca2+ responses that mimic those observed during pre-hearing stages of development, possibly aimed at limiting or preventing further damage to the sensory epithelium. KEY POINTS: Age-related hearing loss is associated with lower hearing sensitivity and decreased ability to understand speech. We investigated age-related changes in the expression and function of metabotropic purinergic (P2Y) receptors in cochlear non-sensory supporting cells of mice displaying early-onset (C57BL/6N) and late-onset (C3H/HeJ) hearing loss. The expression of P2Y1 , P2Y2 and P2Y4 receptors in the supporting cells decreased during cochlear maturation, but that of P2Y2 and P2Y4 was upregulated in the aged cochlea. P2Y2 and P2Y4 receptors were primarily responsible for the ATP-induced Ca2+ responses in the supporting cells. The degree of purinergic expression upregulation in aged supporting cells mirrored hearing loss progression in the different mouse strains. We propose that the upregulation of purinergic-mediated signalling in the aged cochlea is subsequent to age-related changes in the hair cells and may act as a protective mechanism to limit or to avoid further damage to the sensory epithelium.
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Affiliation(s)
- Sarah A. Hool
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Jing‐Yi Jeng
- School of BiosciencesUniversity of SheffieldSheffieldUK
| | | | - Walter Marcotti
- School of BiosciencesUniversity of SheffieldSheffieldUK
- Neuroscience InstituteUniversity of SheffieldSheffieldUK
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26
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Park J, Bird JE. The actin cytoskeleton in hair bundle development and hearing loss. Hear Res 2023; 436:108817. [PMID: 37300948 PMCID: PMC10408727 DOI: 10.1016/j.heares.2023.108817] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/18/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023]
Abstract
Inner ear hair cells assemble mechanosensitive hair bundles on their apical surface that transduce sounds and accelerations. Each hair bundle is comprised of ∼ 100 individual stereocilia that are arranged into rows of increasing height and width; their specific and precise architecture being necessary for mechanoelectrical transduction (MET). The actin cytoskeleton is fundamental to establishing this architecture, not only by forming the structural scaffold shaping each stereocilium, but also by composing rootlets and the cuticular plate that together provide a stable foundation supporting each stereocilium. In concert with the actin cytoskeleton, a large assortment of actin-binding proteins (ABPs) function to cross-link actin filaments into specific topologies, as well as control actin filament growth, severing, and capping. These processes are individually critical for sensory transduction and are all disrupted in hereditary forms of human hearing loss. In this review, we provide an overview of actin-based structures in the hair bundle and the molecules contributing to their assembly and functional properties. We also highlight recent advances in mechanisms driving stereocilia elongation and how these processes are tuned by MET.
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Affiliation(s)
- Jinho Park
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, United States; Myology Institute, University of Florida, Gainesville, FL 32610, United States
| | - Jonathan E Bird
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, United States; Myology Institute, University of Florida, Gainesville, FL 32610, United States.
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27
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Clark S, Jeong H, Posert R, Goehring A, Gouaux E. Structure of C. elegans TMC-2 complex suggests roles of lipid-mediated subunit contacts in mechanosensory transduction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.16.553618. [PMID: 37645790 PMCID: PMC10462014 DOI: 10.1101/2023.08.16.553618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Mechanotransduction is the process by which a mechanical force, such as touch, is converted into an electrical signal. Transmembrane channel-like (TMC) proteins are an evolutionarily-conserved family of ion channels whose function has been linked to a variety of mechanosensory processes, including hearing and balance sensation in vertebrates and locomotion in Drosophila. The molecular features that tune homologous TMC ion channel complexes to diverse mechanical stimuli are unknown. Caenorhabditis elegans express two TMC homologs, TMC-1 and TMC-2, both of which are the likely pore-forming subunits of mechanosensitive ion channels but differ in their expression pattern and functional role in the worm. Here we present the single particle cryo-electron microscopy structure of the native TMC-2 complex isolated from C. elegans. The complex is composed of two copies each of the pore-forming TMC-2 subunit, the calcium and integrin binding protein CALM-1 and the transmembrane inner ear protein TMIE. Comparison of the TMC-2 complex to the recently published cryo-EM structure of the C. elegans TMC-1 complex reveals differences in subunit composition and highlights conserved protein-lipid interactions, as well as other structural features, that together suggest a mechanism for TMC-mediated mechanosensory transduction.
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Affiliation(s)
- Sarah Clark
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Hanbin Jeong
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Rich Posert
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - April Goehring
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, Oregon 97239, USA
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28
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Peters CW, Hanlon KS, Ivanchenko MV, Zinn E, Linarte EF, Li Y, Levy JM, Liu DR, Kleinstiver BP, Indzhykulian AA, Corey DP. Rescue of hearing by adenine base editing in a humanized mouse model of Usher syndrome type 1F. Mol Ther 2023; 31:2439-2453. [PMID: 37312453 PMCID: PMC10421997 DOI: 10.1016/j.ymthe.2023.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/03/2023] [Accepted: 06/08/2023] [Indexed: 06/15/2023] Open
Abstract
Usher syndrome type 1F (USH1F), characterized by congenital lack of hearing and balance and progressive loss of vision, is caused by mutations in the PCDH15 gene. In the Ashkenazi population, a recessive truncation mutation accounts for a large proportion of USH1F cases. The truncation is caused by a single C→T mutation, which converts an arginine codon to a stop (R245X). To test the potential for base editors to revert this mutation, we developed a humanized Pcdh15R245X mouse model for USH1F. Mice homozygous for the R245X mutation were deaf and exhibited profound balance deficits, while heterozygous mice were unaffected. Here we show that an adenine base editor (ABE) is capable of reversing the R245X mutation to restore the PCDH15 sequence and function. We packaged a split-intein ABE into dual adeno-associated virus (AAV) vectors and delivered them into cochleas of neonatal USH1F mice. Hearing was not restored in a Pcdh15 constitutive null mouse despite base editing, perhaps because of early disorganization of cochlear hair cells. However, injection of vectors encoding the split ABE into a late-deletion conditional Pcdh15 knockout rescued hearing. This study demonstrates the ability of an ABE to correct the PCDH15 R245X mutation in the cochlea and restore hearing.
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Affiliation(s)
- Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Killian S Hanlon
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Eric Zinn
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | | | - Yaqiao Li
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jonathan M Levy
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Benjamin P Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Artur A Indzhykulian
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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29
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Aristizábal-Ramírez I, Dragich AK, Giese APJ, Sofia Zuluaga-Osorio K, Watkins J, Davies GK, Hadi SE, Riazuddin S, Vander Kooi CW, Ahmed ZM, Frolenkov GI. Calcium and Integrin-binding protein 2 (CIB2) controls force sensitivity of the mechanotransducer channels in cochlear outer hair cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.09.545606. [PMID: 37461484 PMCID: PMC10350036 DOI: 10.1101/2023.07.09.545606] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Calcium and Integrin-Binding Protein 2 (CIB2) is an essential subunit of the mechano-electrical transduction (MET) complex in mammalian auditory hair cells. CIB2 binds to pore-forming subunits of the MET channel, TMC1/2 and is required for their transport and/or retention at the tips of mechanosensory stereocilia. Since genetic ablation of CIB2 results in complete loss of MET currents, the exact role of CIB2 in the MET complex remains elusive. Here, we generated a new mouse strain with deafness-causing p.R186W mutation in Cib2 and recorded small but still measurable MET currents in the cochlear outer hair cells. We found that R186W variant causes increase of the resting open probability of MET channels, steeper MET current dependence on hair bundle deflection (I-X curve), loss of fast adaptation, and increased leftward shifts of I-X curves upon hair cell depolarization. Combined with AlphaFold2 prediction that R186W disrupts one of the multiple interacting sites between CIB2 and TMC1/2, our data suggest that CIB2 mechanically constraints TMC1/2 conformations to ensure proper force sensitivity and dynamic range of the MET channels. Using a custom piezo-driven stiff probe deflecting the hair bundles in less than 10 µs, we also found that R186W variant slows down the activation of MET channels. This phenomenon, however, is unlikely to be due to direct effect on MET channels, since we also observed R186W-evoked disruption of the electron-dense material at the tips of mechanotransducing stereocilia and the loss of membrane-shaping BAIAP2L2 protein from the same location. We concluded that R186W variant of CIB2 disrupts force sensitivity of the MET channels and force transmission to these channels.
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30
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Abstract
Tip links are seen under microscopes as double-helical tetrameric complexes of long nonclassical cadherins, cadherin-23 and protocadherin-15. The twisted filamentous structure enables tip links to regulate mechanotransduction in hearing and balance. While the molecular details of the double-helical protocadherin-15 cis dimers have been deciphered, a similar conformation of cadherin-23 is still elusive. In a search of cadherin-23 cis dimers, we performed photoinduced cross-linking of unmodified proteins in solution and on lipid membranes and observed no trace of cadherin-23 cis dimers. Reportedly, tip links are dynamic connections, assembling and disassembling in seconds. Using lipid vesicles, we measured significantly slower aggregations between cis dimers of tip link cadherins than via dimer-monomer interactions, indicating that the trans interactions between two cis dimers may possess steric restraints and defer reassociations. Reconnections of tip links are thus kinetically most desired between protocadherin-15 cis dimers and cadherin-23 monomers. Here we propose that the helical geometry of tip links is induced by protocadherin-15 cis dimers, while cadherin-23 remains single before tip linking.
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Affiliation(s)
- Veerpal Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali 140306, Punjab, India
| | - Sanat K Ghosh
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Mohali 140306, Punjab, India
| | - Tripta Bhatia
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Mohali 140306, Punjab, India
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali 140306, Punjab, India
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31
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Lan Y, Hou T, Peng L, Li Y, Yin S. The association of genetic polymorphisms in protocadherin 15 with sudden sensorineural hearing loss in a Chinese population. J Clin Lab Anal 2023:e24896. [PMID: 37198144 DOI: 10.1002/jcla.24896] [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] [Received: 01/07/2023] [Revised: 04/27/2023] [Accepted: 05/04/2023] [Indexed: 05/19/2023] Open
Abstract
BACKGROUND Sudden sensorineural hearing loss (SSNHL) is a multifactorial disease, and its etiology is still unknown. SSNHL may be caused by environmental factors and genetic changes. PCDH15 is associated with susceptibility to hearing loss. The relationship between PCDH15 and SSNHL remains unknown. METHODS In this study, the potential association between PCDH15 polymorphism and SSNHL in Chinese population was evaluated. Two single nucleotide polymorphisms PCDH15-rs7095441 and rs11004085 in 195 SSNHL patients and 182 healthy controls were determined by TaqMan technology. RESULTS In Chinese population, the TT genotype and T allele of rs7095441 are associated with increased susceptibility to SSNHL. The relationships between rs7095441 and the degree of hearing loss were analyzed, and TT genotype increased the risk of hearing loss. Among SSNHL patients, patients with TT genotype of rs7095441 have an increased risk of vertigo. CONCLUSION This study found that the TT genotype of SNP rs7095441 can increase the risk of SSNHL in Chinese population.
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Affiliation(s)
- Ying Lan
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
- Department of Otolaryngology Head and Neck Surgery, The Third Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Tao Hou
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Lu Peng
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Yongpeng Li
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Shihua Yin
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
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Wang X, Liu S, Cheng Q, Qu C, Ren R, Du H, Li N, Yan K, Wang Y, Xiong W, Xu Z. CIB2 and CIB3 Regulate Stereocilia Maintenance and Mechanoelectrical Transduction in Mouse Vestibular Hair Cells. J Neurosci 2023; 43:3219-3231. [PMID: 37001993 PMCID: PMC10162464 DOI: 10.1523/jneurosci.1807-22.2023] [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: 09/22/2022] [Revised: 03/20/2023] [Accepted: 03/25/2023] [Indexed: 04/03/2023] Open
Abstract
The mechanoelectrical transduction (MET) protein complex in the inner-ear hair cells is essential for hearing and balance perception. Calcium and integrin-binding protein 2 (CIB2) has been reported to be a component of MET complex, and loss of CIB2 completely abolishes MET currents in auditory hair cells, causing profound congenital hearing loss. However, loss of CIB2 does not affect MET currents in vestibular hair cells (VHCs) as well as general balance function. Here, we show that CIB2 and CIB3 act redundantly to regulate MET in VHCs, as MET currents are completely abolished in the VHCs of Cib2/Cib3 double knock-out mice of either sex. Furthermore, we show that Cib2 and Cib3 transcripts have complementary expression patterns in the vestibular maculae, and that they play different roles in stereocilia maintenance in VHCs. Cib2 transcripts are highly expressed in the striolar region, and knock-out of Cib2 affects stereocilia maintenance in striolar VHCs. In contrast, Cib3 transcripts are highly expressed in the extrastriolar region, and knock-out of Cib3 mainly affects stereocilia maintenance in extrastriolar VHCs. Simultaneous knock-out of Cib2 and Cib3 affects stereocilia maintenance in all VHCs and leads to severe balance deficits. Taken together, our present work reveals that CIB2 and CIB3 are important for stereocilia maintenance as well as MET in mouse VHCs.SIGNIFICANCE STATEMENT Calcium and integrin-binding protein 2 (CIB2) is an important component of mechanoelectrical transduction (MET) complex, and loss of CIB2 completely abolishes MET in auditory hair cells. However, MET is unaffected in Cib2 knock-out vestibular hair cells (VHCs). In the present work, we show that CIB3 could compensate for the loss of CIB2 in VHCs, and Cib2/Cib3 double knock-out completely abolishes MET in VHCs. Interestingly, CIB2 and CIB3 could also regulate VHC stereocilia maintenance in a nonredundant way. Cib2 and Cib3 transcripts are highly expressed in the striolar and extrastriolar regions, respectively. Stereocilia maintenance and balance function are differently affected in Cib2 or Cib3 knock-out mice. In conclusion, our data suggest that CIB2 and CIB3 are important for stereocilia maintenance and MET in mouse VHCs.
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Affiliation(s)
- Xiaoying Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Shuang Liu
- School of Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, People's Republic of China
- Chinese Institute for Brain Research, Beijing 102206, People's Republic of China
| | - Qi Cheng
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Chengli Qu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Rui Ren
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Nana Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Keji Yan
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Wei Xiong
- School of Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, People's Republic of China
- Chinese Institute for Brain Research, Beijing 102206, People's Republic of China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
- Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, Shandong 250014, People's Republic of China
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Nishiguchi S, Kasai RS, Uchihashi T. Antiparallel dimer structure of CELSR cadherin in solution revealed by high-speed atomic force microscopy. Proc Natl Acad Sci U S A 2023; 120:e2302047120. [PMID: 37094146 PMCID: PMC10160967 DOI: 10.1073/pnas.2302047120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/03/2023] [Indexed: 04/26/2023] Open
Abstract
Cadherin EGF LAG seven-pass G-type receptors (CELSR) cadherins, members of the cadherin superfamily, and adhesion G-protein-coupled receptors, play a vital role in cell-cell adhesion. The mutual binding of the extracellular domains (ectodomains) of CELSR cadherins between cells is crucial for tissue formation, including the establishment of planar cell polarity, which directs the proper patterning of cells. CELSR cadherins possess nine cadherin ectodomains (EC1-EC9) and noncadherin ectodomains. However, the structural and functional mechanisms of the binding mode of CELSR cadherins have not been determined. In this study, we investigated the binding mode of CELSR cadherins using single-molecule fluorescence microscopy, high-speed atomic force microscopy (HS-AFM), and bead aggregation assay. The fluorescence microscopy analysis results indicated that the trans-dimer of the CELSR cadherin constitutes the essential adhesive unit between cells. HS-AFM analysis and bead aggregation assay results demonstrated that EC1-EC8 entirely overlap and twist to form antiparallel dimer conformations and that the binding of EC1-EC4 is sufficient to sustain bead aggregation. The interaction mechanism of CELSR cadherin may elucidate the variation of the binding mechanism within the cadherin superfamily and physiological role of CELSR cadherins in relation to planar cell polarity.
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Affiliation(s)
- Shigetaka Nishiguchi
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki444-8787, Japan
| | - Rinshi S. Kasai
- Institute for Life and Medical Sciences, Kyoto University, Kyoto606-8507, Japan
- Institute for Glyco-core Research, Gifu University, Gifu501-1193, Japan
| | - Takayuki Uchihashi
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki444-8787, Japan
- Department of Physics, Nagoya University, Nagoya464-8602, Japan
- Institute for Glyco-core Research, Nagoya University, Nagoya464-8602, Japan
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Ivanchenko MV, Hathaway DM, Klein AJ, Pan B, Strelkova O, De-la-Torre P, Wu X, Peters CW, Mulhall EM, Booth KT, Goldstein C, Brower J, Sotomayor M, Indzhykulian AA, Corey DP. Mini-PCDH15 gene therapy rescues hearing in a mouse model of Usher syndrome type 1F. Nat Commun 2023; 14:2400. [PMID: 37100771 PMCID: PMC10133396 DOI: 10.1038/s41467-023-38038-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/11/2023] [Indexed: 04/28/2023] Open
Abstract
Usher syndrome type 1 F (USH1F), caused by mutations in the protocadherin-15 gene (PCDH15), is characterized by congenital deafness, lack of balance, and progressive blindness. In hair cells, the receptor cells of the inner ear, PCDH15 is a component of tip links, fine filaments which pull open mechanosensory transduction channels. A simple gene addition therapy for USH1F is challenging because the PCDH15 coding sequence is too large for adeno-associated virus (AAV) vectors. We use rational, structure-based design to engineer mini-PCDH15s in which 3-5 of the 11 extracellular cadherin repeats are deleted, but which still bind a partner protein. Some mini-PCDH15s can fit in an AAV. An AAV encoding one of these, injected into the inner ears of mouse models of USH1F, produces a mini-PCDH15 which properly forms tip links, prevents the degeneration of hair cell bundles, and rescues hearing. Mini-PCDH15s may be a useful therapy for the deafness of USH1F.
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Affiliation(s)
| | - Daniel M Hathaway
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Alex J Klein
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Bifeng Pan
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Olga Strelkova
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Xudong Wu
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Eric M Mulhall
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Kevin T Booth
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Corey Goldstein
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Joseph Brower
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Artur A Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
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Krey JF, Chatterjee P, Halford J, Cunningham CL, Perrin BJ, Barr-Gillespie PG. Control of stereocilia length during development of hair bundles. PLoS Biol 2023; 21:e3001964. [PMID: 37011103 PMCID: PMC10101650 DOI: 10.1371/journal.pbio.3001964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/13/2023] [Accepted: 03/14/2023] [Indexed: 04/05/2023] Open
Abstract
Assembly of the hair bundle, the sensory organelle of the inner ear, depends on differential growth of actin-based stereocilia. Separate rows of stereocilia, labeled 1 through 3 from tallest to shortest, lengthen or shorten during discrete time intervals during development. We used lattice structured illumination microscopy and surface rendering to measure dimensions of stereocilia from mouse apical inner hair cells during early postnatal development; these measurements revealed a sharp transition at postnatal day 8 between stage III (row 1 and 2 widening; row 2 shortening) and stage IV (final row 1 lengthening and widening). Tip proteins that determine row 1 lengthening did not accumulate simultaneously during stages III and IV; while the actin-bundling protein EPS8 peaked at the end of stage III, GNAI3 peaked several days later-in early stage IV-and GPSM2 peaked near the end of stage IV. To establish the contributions of key macromolecular assemblies to bundle structure, we examined mouse mutants that eliminated tip links (Cdh23v2J or Pcdh15av3J), transduction channels (TmieKO), or the row 1 tip complex (Myo15ash2). Cdh23v2J/v2J and Pcdh15av3J/av3J bundles had adjacent stereocilia in the same row that were not matched in length, revealing that a major role of these cadherins is to synchronize lengths of side-by-side stereocilia. Use of the tip-link mutants also allowed us to distinguish the role of transduction from effects of transduction proteins themselves. While levels of GNAI3 and GPSM2, which stimulate stereocilia elongation, were greatly attenuated at the tips of TmieKO/KO row 1 stereocilia, they accumulated normally in Cdh23v2J/v2J and Pcdh15av3J/av3J stereocilia. These results reinforced the suggestion that the transduction proteins themselves facilitate localization of proteins in the row 1 complex. By contrast, EPS8 concentrates at tips of all TmieKO/KO, Cdh23v2J/v2J, and Pcdh15av3J/av3J stereocilia, correlating with the less polarized distribution of stereocilia lengths in these bundles. These latter results indicated that in wild-type hair cells, the transduction complex prevents accumulation of EPS8 at the tips of shorter stereocilia, causing them to shrink (rows 2 and 3) or disappear (row 4 and microvilli). Reduced rhodamine-actin labeling at row 2 stereocilia tips of tip-link and transduction mutants suggests that transduction's role is to destabilize actin filaments there. These results suggest that regulation of stereocilia length occurs through EPS8 and that CDH23 and PCDH15 regulate stereocilia lengthening beyond their role in gating mechanotransduction channels.
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Affiliation(s)
- Jocelyn F. Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Paroma Chatterjee
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Julia Halford
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Christopher L. Cunningham
- Pittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Benjamin J. Perrin
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana, United States of America
| | - Peter G. Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health & Science University, Portland, Oregon, United States of America
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36
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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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37
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Wang Y, Zhang C, Peng W, Du H, Xi Y, Xu Z. RBM24 is required for mouse hair cell development through regulating pre-mRNA alternative splicing and mRNA stability. J Cell Physiol 2023; 238:1095-1110. [PMID: 36947695 DOI: 10.1002/jcp.31003] [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: 12/30/2022] [Revised: 02/28/2023] [Accepted: 03/06/2023] [Indexed: 03/24/2023]
Abstract
As the sensory receptor cells in vertebrate inner ear and lateral lines, hair cells are characterized by the hair bundle that consists of one tubulin-based kinocilium and dozens of actin-based stereocilia on the apical surface of each hair cell. Hair cell development is tightly regulated, and deficits in this process usually lead to hearing loss and/or balance dysfunctions. RNA-binding motif protein 24 (RBM24) is an RNA-binding protein that is specifically expressed in the hair cells in the inner ear. Previously, we showed that RBM24 affects hair cell development in zebrafish by regulating messenger RNA (mRNA) stability. In the present work, we further investigate the role of RBM24 in hearing and balance using conditional knockout mice. Our results show that Rbm24 knockout results in severe hearing and balance deficits. Hair cell development is significantly affected in Rbm24 knockout cochlea, as the hair bundles are poorly developed and eventually degenerated. Hair bundle disorganization is also observed in Rbm24 knockout vestibular hair cells, although to a lesser extent. Consistently, significant hair cell loss is observed in the cochlea but not vestibule. RNAseq analysis identified several genes whose mRNA stability or pre-mRNA alternative splicing is affected by Rbm24 knockout. Among them are Cdh23, Pcdh15, and Myo7a, which have been shown to play important roles in stereocilia development as well as mechano-electrical transduction. Taken together, our present work suggests that RBM24 is required for mouse hair cell development through regulating pre-mRNA alternative splicing as well as mRNA stability.
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Affiliation(s)
- Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Cuiqiao Zhang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Wu Peng
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Yuehui Xi
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, China
- Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, Shandong, China
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Srinivas CS, Singaraju GS, Kaur V, Das S, Ghosh SK, Sagar A, Kumar A, Bhatia T, Rakshit S. Transient interactions drive the lateral clustering of cadherin-23 on membrane. Commun Biol 2023; 6:293. [PMID: 36934176 PMCID: PMC10024700 DOI: 10.1038/s42003-023-04677-6] [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: 09/21/2022] [Accepted: 03/07/2023] [Indexed: 03/20/2023] Open
Abstract
Cis and trans-interactions among cadherins secure multicellularity. While the molecular structure of trans-interactions of cadherins is well understood, work to identify the molecular cues that spread the cis-interactions two-dimensionally is still ongoing. Here, we report that transient, weak, yet multivalent, and spatially distributed hydrophobic interactions that are involved in liquid-liquid phase separations of biomolecules in solution, alone can drive the lateral-clustering of cadherin-23 on a membrane. No specific cis-dimer interactions are required for the lateral clustering. In cells, the cis-clustering accelerates cell-cell adhesion and, thus, contributes to cell-adhesion kinetics along with strengthening the junction. Although the physiological connection of cis-clustering with rapid adhesion is yet to be explored, we speculate that the over-expression of cadherin-23 in M2-macrophages may facilitate faster attachments to circulatory tumor cells during metastasis.
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Affiliation(s)
- Cheerneni S Srinivas
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Gayathri S Singaraju
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Veerpal Kaur
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Sayan Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Sanat K Ghosh
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Amin Sagar
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Anuj Kumar
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
- Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Tripta Bhatia
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Sabyasachi Rakshit
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
- Centre for Protein Science Design and Engineering, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
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The tetraspan LHFPL5 is critical to establish maximal force sensitivity of the mechanotransduction channel of cochlear hair cells. Cell Rep 2023; 42:112245. [PMID: 36917610 DOI: 10.1016/j.celrep.2023.112245] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/28/2023] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
The mechanoelectrical transduction (MET) channel of cochlear hair cells is gated by the tip link, but the mechanisms that establish the exquisite force sensitivity of this MET channel are not known. Here, we show that the tetraspan lipoma HMGIC fusion partner-like 5 (LHFPL5) directly couples the tip link to the MET channel. Disruption of these interactions severely perturbs MET. Notably, the N-terminal cytoplasmic domain of LHFPL5 binds to an amphipathic helix in TMC1, a critical gating domain conserved between different MET channels. Mutations in the amphipathic helix of TMC1 or in the N-terminus of LHFPL5 that perturb interactions of LHFPL5 with the amphipathic helix affect channel responses to mechanical force. We conclude that LHFPL5 couples the tip link to the MET channel and that channel gating depends on a structural element in TMC1 that is evolutionarily conserved between MET channels. Overall, our findings support a tether model for transduction channel gating by the tip link.
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Sharkova M, Chow E, Erickson T, Hocking JC. The morphological and functional diversity of apical microvilli. J Anat 2023; 242:327-353. [PMID: 36281951 PMCID: PMC9919547 DOI: 10.1111/joa.13781] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022] Open
Abstract
Sensory neurons use specialized apical processes to perceive external stimuli and monitor internal body conditions. The apical apparatus can include cilia, microvilli, or both, and is adapted for the functions of the particular cell type. Photoreceptors detect light through a large, modified cilium (outer segment), that is supported by a surrounding ring of microvilli-like calyceal processes (CPs). Although first reported 150 years ago, CPs remain poorly understood. As a basis for future study, we therefore conducted a review of existing literature about sensory cell microvilli, which can act either as the primary sensory detector or as support for a cilia-based detector. While all microvilli are finger-like cellular protrusions with an actin core, the processes vary across cell types in size, number, arrangement, dynamics, and function. We summarize the current state of knowledge about CPs and the characteristics of the microvilli found on inner ear hair cells (stereocilia) and cerebral spinal fluid-contacting neurons, with comparisons to the brush border of the intestinal and renal epithelia. The structure, stability, and dynamics of the actin core are regulated by a complement of actin-binding proteins, which includes both common components and unique features when compared across cell types. Further, microvilli are often supported by lateral links, a glycocalyx, and a defined extracellular matrix, each adapted to the function and environment of the cell. Our comparison of microvillar features will inform further research into how CPs support photoreceptor function, and also provide a general basis for investigations into the structure and functions of apical microvilli found on sensory neurons.
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Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Erica Chow
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jennifer C Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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41
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Calcium signaling and genetic rare diseases: An auditory perspective. Cell Calcium 2023; 110:102702. [PMID: 36791536 DOI: 10.1016/j.ceca.2023.102702] [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: 12/14/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/07/2023]
Abstract
Deafness is a highly heterogeneous disorder which stems, for 50%, from genetic origins. Sensory transduction relies mainly on sensory hair cells of the cochlea, in the inner ear. Calcium is key for the function of these cells and acts as a fundamental signal transduction. Its homeostasis depends on three factors: the calcium influx, through the mechanotransduction channel at the apical pole of the hair cell as well as the voltage-gated calcium channel at the base of the cells; the calcium buffering via Ca2+-binding proteins in the cytoplasm, but also in organelles such as mitochondria and the reticulum endoplasmic mitochondria-associated membranes with specialized proteins; and the calcium extrusion through the Ca-ATPase pump, located all over the plasma membrane. In addition, the synaptic transmission to the central nervous system is also controlled by calcium. Genetic studies of inherited deafness have tremendously helped understand the underlying molecular pathways of calcium signaling. In this review, we discuss these different factors in light of the associated genetic diseases (syndromic and non-syndromic deafness) and the causative genes.
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Rajan S, Kudryashov DS, Reisler E. Actin Bundles Dynamics and Architecture. Biomolecules 2023; 13:450. [PMID: 36979385 PMCID: PMC10046292 DOI: 10.3390/biom13030450] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/04/2023] Open
Abstract
Cells use the actin cytoskeleton for many of their functions, including their division, adhesion, mechanosensing, endo- and phagocytosis, migration, and invasion. Actin bundles are the main constituent of actin-rich structures involved in these processes. An ever-increasing number of proteins that crosslink actin into bundles or regulate their morphology is being identified in cells. With recent advances in high-resolution microscopy and imaging techniques, the complex process of bundles formation and the multiple forms of physiological bundles are beginning to be better understood. Here, we review the physiochemical and biological properties of four families of highly conserved and abundant actin-bundling proteins, namely, α-actinin, fimbrin/plastin, fascin, and espin. We describe the similarities and differences between these proteins, their role in the formation of physiological actin bundles, and their properties-both related and unrelated to their bundling abilities. We also review some aspects of the general mechanism of actin bundles formation, which are known from the available information on the activity of the key actin partners involved in this process.
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Affiliation(s)
- Sudeepa Rajan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Dmitri S. Kudryashov
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA
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43
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Structure of the planar cell polarity cadherins Fat4 and Dachsous1. Nat Commun 2023; 14:891. [PMID: 36797229 PMCID: PMC9935876 DOI: 10.1038/s41467-023-36435-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/01/2023] [Indexed: 02/18/2023] Open
Abstract
The atypical cadherins Fat and Dachsous are key regulators of cell growth and animal development. In contrast to classical cadherins, which form homophilic interactions to segregate cells, Fat and Dachsous cadherins form heterophilic interactions to induce cell polarity within tissues. Here, we determine the co-crystal structure of the human homologs Fat4 and Dachsous1 (Dchs1) to establish the molecular basis for Fat-Dachsous interactions. The binding domains of Fat4 and Dchs1 form an extended interface along extracellular cadherin (EC) domains 1-4 of each protein. Biophysical measurements indicate that Fat4-Dchs1 affinity is among the highest reported for cadherin superfamily members, which is attributed to an extensive network of salt bridges not present in structurally similar protocadherin homodimers. Furthermore, modeling suggests that unusual extracellular phosphorylation modifications directly modulate Fat-Dachsous binding by introducing charged contacts across the interface. Collectively, our analyses reveal how the molecular architecture of Fat4-Dchs1 enables them to form long-range, high-affinity interactions to maintain planar cell polarity.
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44
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Wang X, Fan Q, Yu X, Wang Y. Cellular distribution of the Fragile X mental retardation protein in the inner ear: a developmental and comparative study in the mouse, rat, gerbil, and chicken. J Comp Neurol 2023; 531:149-169. [PMID: 36222577 PMCID: PMC9691623 DOI: 10.1002/cne.25420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 09/08/2022] [Accepted: 09/16/2022] [Indexed: 11/11/2022]
Abstract
The Fragile X mental retardation protein (FMRP) is an mRNA binding protein that is essential for neural circuit assembly and synaptic plasticity. Loss of functional FMRP leads to Fragile X syndrome (FXS), a neurodevelopmental disorder characterized by sensory dysfunction including abnormal auditory processing. While the central mechanisms of FMRP regulation have been studied in the brain, whether FMRP is expressed in the auditory periphery and how it develops and functions remains unknown. In this study, we characterized the spatiotemporal distribution pattern of FMRP immunoreactivity in the inner ear of mice, rats, gerbils, and chickens. Across species, FMRP was expressed in hair cells and supporting cells, with a particularly high level in immature hair cells during the prehearing period. Interestingly, the distribution of cytoplasmic FMRP displayed an age-dependent translocation in hair cells, and this feature was conserved across species. In the auditory ganglion (AG), FMRP immunoreactivity was detected in neuronal cell bodies as well as their peripheral and central processes. Distinct from hair cells, FMRP intensity in AG neurons was high both during development and after maturation. Additionally, FMRP was evident in mature glial cells surrounding AG neurons. Together, these observations demonstrate distinct developmental trajectories across cell types in the auditory periphery. Given the importance of peripheral inputs to the maturation of auditory circuits, these findings implicate involvement of FMRP in inner ear development as well as a potential contribution of periphery FMRP to the generation of auditory dysfunction in FXS.
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Affiliation(s)
- Xiaoyu Wang
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, College of Medicine, Jinan University, Guangzhou 510632, China
- Program in Neuroscience, Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Qiwei Fan
- Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, College of Medicine, Jinan University, Guangzhou 510632, China
| | - Xiaoyan Yu
- Program in Neuroscience, Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
| | - Yuan Wang
- Program in Neuroscience, Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306, USA
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45
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Li J. Liquid-liquid phase separation in hair cell stereocilia development and maintenance. Comput Struct Biotechnol J 2023; 21:1738-1745. [PMID: 36890881 PMCID: PMC9986246 DOI: 10.1016/j.csbj.2023.02.040] [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: 10/28/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
As an emerging concept, liquid-liquid phase separation (LLPS) in biological systems has shed light on the formation mechanisms of membrane-less compartments in cells. The process is driven by multivalent interactions of biomolecules such as proteins and/or nucleic acids, allowing them to form condensed structures. In the inner ear hair cells, LLPS-based biomolecular condensate assembly plays a vital role in the development and maintenance of stereocilia, the mechanosensing organelles located at the apical surface of hair cells. This review aims to summarize recent findings on the molecular basis governing the LLPS of Usher syndrome-related gene-encoding proteins and their binding partners, which may ultimately result in the formation of upper tip-link density and tip complex density in hair cell stereocilia, offering a better understanding of this severe inherited disease that causes deaf-blindness.
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Affiliation(s)
- Jianchao Li
- Department of Otorhinolaryngology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou 510180, China.,Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
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46
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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: 18] [Impact Index Per Article: 9.0] [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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47
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Dooley SA, Engevik KA, Digrazia J, Stubler R, Kaji I, Krystofiak E, Engevik AC. Myosin 5b is required for proper localization of the intermicrovillar adhesion complex in the intestinal brush border. Am J Physiol Gastrointest Liver Physiol 2022; 323:G501-G510. [PMID: 36218265 PMCID: PMC9639760 DOI: 10.1152/ajpgi.00212.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/27/2022] [Accepted: 10/03/2022] [Indexed: 01/31/2023]
Abstract
Intestinal enterocytes have an elaborate apical membrane of actin-rich protrusions known as microvilli. The organization of microvilli is orchestrated by the intermicrovillar adhesion complex (IMAC), which connects the distal tips of adjacent microvilli. The IMAC is composed of CDHR2 and CDHR5 as well as the scaffolding proteins USH1C, ANKS4B, and Myosin 7b (MYO7B). To create an IMAC, cells must transport the proteins to the apical membrane. Myosin 5b (MYO5B) is a molecular motor that traffics ion transporters to the apical membrane of enterocytes, and we hypothesized that MYO5B may also be responsible for the localization of IMAC proteins. To address this question, we used two different mouse models: 1) neonatal germline MYO5B knockout (MYO5B KO) mice and 2) adult intestinal-specific tamoxifen-inducible VillinCreERT2;MYO5Bflox/flox mice. In control mice, immunostaining revealed that CDHR2, CDHR5, USH1C, and MYO7B were highly enriched at the tips of the microvilli. In contrast, neonatal germline and adult MYO5B-deficient mice showed loss of apical CDHR2, CDHR5, and MYO7B in the brush border and accumulation in a subapical compartment. Colocalization analysis revealed decreased Mander's coefficients in adult inducible MYO5B-deficient mice compared with control mice for CDHR2, CDHR5, USH1C, and MYO7B. Scanning electron microscopy images further demonstrated aberrant microvilli packing in adult inducible MYO5B-deficient mouse small intestine. These data indicate that MYO5B is responsible for the delivery of IMAC components to the apical membrane.NEW & NOTEWORTHY The intestinal epithelium absorbs nutrients and water through an elaborate apical membrane of highly organized microvilli. Microvilli organization is regulated by the intermicrovillar adhesion complexes, which create links between neighboring microvilli and control microvilli packing and density. In this study, we report a new trafficking partner of the IMAC, Myosin 5b. Loss of Myosin 5b results in a disorganized brush border and failure of IMAC proteins to reach the distal tips of microvilli.
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Affiliation(s)
- Sarah A Dooley
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina
| | - Kristen A Engevik
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
| | - Jessica Digrazia
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina
| | - Rachel Stubler
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina
| | - Izumi Kaji
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee
- Epithelial Biology Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Evan Krystofiak
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
- Cell Imaging Shared Resource, Vanderbilt University, Nashville, Tennessee
| | - Amy C Engevik
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina
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48
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The conductance and organization of the TMC1-containing mechanotransducer channel complex in auditory hair cells. Proc Natl Acad Sci U S A 2022; 119:e2210849119. [PMID: 36191207 PMCID: PMC9564823 DOI: 10.1073/pnas.2210849119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We studied the role of TMC1 as the central component of the hair cell mechanotransducer (MET) channel by characterizing transduction in mice harboring mutations in the pore region. All Tmc1 mutations reduced the Ca2+ influx into the hair bundle. Two mutations (Tmc1 p.D528N or Tmc1 p.E520Q) also decreased channel conductance and two (Tmc1 p. D569N or Tmc1 p.W554L) lowered expression. These mutations endorse TMC1 as the pore of the MET channel. The MET channel also contains accessory subunits, LHFPL5 and TMIE. MET currents were small in Lhfpl5 or Tmie knockout mice. Nevertheless, MET channels could still be activated by hair bundle displacement; single-channel conductance was unaffected in Lhfpl5−/− but reduced in Tmie−/−, suggesting TMIE likely contributes to the pore. Transmembrane channel-like protein 1 (TMC1) is thought to form the ion-conducting pore of the mechanoelectrical transducer (MET) channel in auditory hair cells. Using single-channel analysis and ionic permeability measurements, we characterized six missense mutations in the purported pore region of mouse TMC1. All mutations reduced the Ca2+ permeability of the MET channel, triggering hair cell apoptosis and deafness. In addition, Tmc1 p.E520Q and Tmc1 p.D528N reduced channel conductance, whereas Tmc1 p.W554L and Tmc1 p.D569N lowered channel expression without affecting the conductance. Tmc1 p.M412K and Tmc1 p.T416K reduced only the Ca2+ permeability. The consequences of these mutations endorse TMC1 as the pore of the MET channel. The accessory subunits, LHFPL5 and TMIE, are thought to be involved in targeting TMC1 to the tips of the stereocilia. We found sufficient expression of TMC1 in outer hair cells of Lhfpl5 and Tmie knockout mice to determine the properties of the channels, which could still be gated by hair bundle displacement. Single-channel conductance was unaffected in Lhfpl5−/− but was reduced in Tmie−/−, implying TMIE very likely contributes to the pore. Both the working range and half-saturation point of the residual MET current in Lhfpl5−/− were substantially increased, suggesting that LHFPL5 is part of the mechanical coupling between the tip-link and the MET channel. Based on counts of numbers of stereocilia per bundle, we estimate that each PCDH15 and LHFPL5 monomer may contact two channels irrespective of location.
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49
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Gaspar LM, Gonçalves CI, Fonseca F, Carvalho D, Cortez L, Palha A, Barros IF, Nobre E, Duarte JS, Amaral C, Bugalho MJ, Marques O, Pereira BD, Lemos MC. A Common Variant in the CDK8 Gene Is Associated with Sporadic Pituitary Adenomas in the Portuguese Population: A Case-Control Study. Int J Mol Sci 2022; 23:ijms231911749. [PMID: 36233050 PMCID: PMC9570112 DOI: 10.3390/ijms231911749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/21/2022] [Accepted: 10/01/2022] [Indexed: 11/16/2022] Open
Abstract
The majority of pituitary adenomas occur in a sporadic context, and in the absence of known genetic predisposition. Three common variants at the NEBL (rs2359536), PCDH15 (rs10763170) and CDK8 (rs17083838) loci were previously associated with sporadic pituitary adenomas in the Han Chinese population, but these findings have not yet been replicated in any other population. The aim of this case-control study was to assess if these variants are associated with susceptibility to sporadic pituitary adenomas in the Portuguese population. Genotype and allele frequencies were determined in 570 cases and in 546 controls. The CDK8 rs17083838 minor allele (A allele) was significantly associated with sporadic pituitary adenomas, under an additive (odds ratio (OR) 1.73, 95% confidence interval (CI) 1.19–2.50, p = 0.004) and dominant (OR 1.82, 95% CI 1.24–2.68, p = 0.002) inheritance model. The NEBL rs2359536 and PCDH15 rs10763170 variants were not associated with the overall risk for the disease, although a borderline significant association was observed between the PCDH15 rs10763170 minor allele (T allele) and somatotrophinomas (dominant model, OR 1.55, 95% CI 1.02–2.35, p = 0.035). These findings suggest that the CDK8 rs17083838 variant, and possibly the PCDH15 rs10763170 variant, may increase susceptibility to sporadic pituitary adenomas in the Portuguese population.
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Affiliation(s)
- Leonor M. Gaspar
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Catarina I. Gonçalves
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Fernando Fonseca
- Serviço de Endocrinologia, Hospital de Curry Cabral, Centro Hospitalar Universitário Lisboa Central, 1050-099 Lisboa, Portugal
| | - Davide Carvalho
- Serviço de Endocrinologia, Diabetes e Metabolismo, Centro Hospitalar de São João, Faculdade de Medicina e Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-319 Porto, Portugal
| | - Luísa Cortez
- Serviço de Endocrinologia, Hospital de Curry Cabral, Centro Hospitalar Universitário Lisboa Central, 1050-099 Lisboa, Portugal
| | - Ana Palha
- Serviço de Endocrinologia, Hospital de Curry Cabral, Centro Hospitalar Universitário Lisboa Central, 1050-099 Lisboa, Portugal
| | - Inês F. Barros
- Serviço de Endocrinologia, Hospital de Braga, 4710-243 Braga, Portugal
| | - Ema Nobre
- Serviço de Endocrinologia, Diabetes e Metabolismo, Hospital de Santa Maria, Centro Hospitalar Universitário Lisboa Norte, 1649-028 Lisboa, Portugal
| | - João S. Duarte
- Serviço de Endocrinologia, Hospital de Egas Moniz, Centro Hospitalar Lisboa Ocidental, 1349-019 Lisboa, Portugal
| | - Cláudia Amaral
- Serviço de Endocrinologia, Hospital de Santo António, Centro Hospitalar Universitário do Porto, 4099-001 Porto, Portugal
| | - Maria J. Bugalho
- Serviço de Endocrinologia, Diabetes e Metabolismo, Hospital de Santa Maria, Centro Hospitalar Universitário Lisboa Norte, 1649-028 Lisboa, Portugal
| | - Olinda Marques
- Serviço de Endocrinologia, Hospital de Braga, 4710-243 Braga, Portugal
| | - Bernardo D. Pereira
- Serviço de Endocrinologia e Nutrição, Hospital do Divino Espírito Santo de Ponta Delgada, 9500-782 Ponta Delgada, Portugal
| | - Manuel C. Lemos
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal
- Correspondence:
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50
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Selective binding and transport of protocadherin 15 isoforms by stereocilia unconventional myosins in a heterologous expression system. Sci Rep 2022; 12:13764. [PMID: 35962067 PMCID: PMC9374675 DOI: 10.1038/s41598-022-17757-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 07/30/2022] [Indexed: 11/09/2022] Open
Abstract
During hair cell development, the mechanoelectrical transduction (MET) apparatus is assembled at the stereocilia tips, where it coexists with the stereocilia actin regulatory machinery. While the myosin-based tipward transport of actin regulatory proteins is well studied, isoform complexity and built-in redundancies in the MET apparatus have limited our understanding of how MET components are transported. We used a heterologous expression system to elucidate the myosin selective transport of isoforms of protocadherin 15 (PCDH15), the protein that mechanically gates the MET apparatus. We show that MYO7A selectively transports the CD3 isoform while MYO3A and MYO3B transports the CD2 isoform. Furthermore, MYO15A showed an insignificant role in the transport of PCDH15, and none of the myosins tested transport PCDH15-CD1. Our data suggest an important role for MYO3A, MYO3B, and MYO7A in the MET apparatus formation and highlight the intricate nature of MET and actin regulation during development and functional maturation of the stereocilia bundle.
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