1
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Inner Ear Gene Therapies Take Off: Current Promises and Future Challenges. J Clin Med 2020; 9:jcm9072309. [PMID: 32708116 PMCID: PMC7408650 DOI: 10.3390/jcm9072309] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 11/16/2022] Open
Abstract
Hearing impairment is the most frequent sensory deficit in humans of all age groups, from children (1/500) to the elderly (more than 50% of the over-75 s). Over 50% of congenital deafness are hereditary in nature. The other major causes of deafness, which also may have genetic predisposition, are aging, acoustic trauma, ototoxic drugs such as aminoglycosides, and noise exposure. Over the last two decades, the study of inherited deafness forms and related animal models has been instrumental in deciphering the molecular, cellular, and physiological mechanisms of disease. However, there is still no curative treatment for sensorineural deafness. Hearing loss is currently palliated by rehabilitation methods: conventional hearing aids, and for more severe forms, cochlear implants. Efforts are continuing to improve these devices to help users to understand speech in noisy environments and to appreciate music. However, neither approach can mediate a full recovery of hearing sensitivity and/or restoration of the native inner ear sensory epithelia. New therapeutic approaches based on gene transfer and gene editing tools are being developed in animal models. In this review, we focus on the successful restoration of auditory and vestibular functions in certain inner ear conditions, paving the way for future clinical applications.
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2
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Yao Q, Wang L, Mittal R, Yan D, Richmond MT, Denyer S, Requena T, Liu K, Varshney GK, Lu Z, Liu XZ. Transcriptomic Analyses of Inner Ear Sensory Epithelia in Zebrafish. Anat Rec (Hoboken) 2019; 303:527-543. [PMID: 31883312 DOI: 10.1002/ar.24331] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 08/01/2019] [Accepted: 11/18/2019] [Indexed: 12/25/2022]
Abstract
Analysis of gene expression has the potential to assist in the understanding of multiple cellular processes including proliferation, cell-fate specification, senesence, and activity in both healthy and disease states. Zebrafish model has been increasingly used to understand the process of hearing and the development of the vertebrate auditory system. Within the zebrafish inner ear, there are three otolith organs, each containing a sensory macula of hair cells. The saccular macula is primarily involved in hearing, the utricular macula is primarily involved in balance and the function of the lagenar macula is not completely understood. The goal of this study is to understand the transcriptional differences in the sensory macula associated with different otolith organs with the intention of understanding the genetic mechanisms responsible for the distinct role each organ plays in sensory perception. The sensory maculae of the saccule, utricle, and lagena were dissected out of adult Et(krt4:GFP)sqet4 zebrafish expressing green fluorescent protein in hair cells for transcriptional analysis. The total RNAs of the maculae were isolated and analyzed by RNA GeneChip microarray. Several of the differentially expressed genes are known to be involved in deafness, otolith development and balance. Gene expression among these otolith organs was very well conserved with less than 10% of genes showing differential expression. Data from this study will help to elucidate which genes are involved in hearing and balance. Furthermore, the findings of this study will assist in the development of the zebrafish model for human hearing and balance disorders. Anat Rec, 303:527-543, 2020. © 2019 American Association for Anatomy.
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Affiliation(s)
- Qi Yao
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Biology, University of Miami, Miami, Florida
| | - Lingyu Wang
- Department of Biology, University of Miami, Miami, Florida
| | - Rahul Mittal
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida
| | - Denise Yan
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida
| | | | - Steven Denyer
- Department of Biology, University of Miami, Miami, Florida
| | - Teresa Requena
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Kaili Liu
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Gaurav K Varshney
- Genes & Human Disease Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Zhongmin Lu
- Department of Biology, University of Miami, Miami, Florida
| | - Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida.,Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha, Hunan, China
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3
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Girotto G, Morgan A, Krishnamoorthy N, Cocca M, Brumat M, Bassani S, La Bianca M, Di Stazio M, Gasparini P. Next Generation Sequencing and Animal Models Reveal SLC9A3R1 as a New Gene Involved in Human Age-Related Hearing Loss. Front Genet 2019; 10:142. [PMID: 30863428 PMCID: PMC6399162 DOI: 10.3389/fgene.2019.00142] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/11/2019] [Indexed: 01/29/2023] Open
Abstract
Age-related hearing loss (ARHL) is the most common sensory impairment in the elderly affecting millions of people worldwide. To shed light on the genetics of ARHL, a large cohort of 464 Italian patients has been deeply characterized at clinical and molecular level. In particular, 46 candidate genes, selected on the basis of genome-wide association studies (GWAS), animal models and literature updates, were analyzed by targeted re-sequencing. After filtering and prioritization steps, SLC9A3R1 has been identified as a strong candidate and then validated by "in vitro" and "in vivo" studies. Briefly, a rare (MAF: 2.886e-5) missense variant c.539G > A, p.(R180Q) was detected in two unrelated male patients affected by ARHL characterized by a severe to profound high-frequency hearing loss. The variant, predicted as damaging, was not present in healthy matched controls. Protein modeling confirmed the pathogenic effect of p.(R180Q) variant on protein's structure leading to a change in the total number of hydrogen bonds. In situ hybridization showed slc9a3r1 expression in zebrafish inner ear. A zebrafish knock-in model, generated by CRISPR-Cas9 technology, revealed a reduced auditory response at all frequencies in slc9a3r1 R180Q/R180Q mutants compared to slc9a3r1 +/+ and slc9a3r1 +/R180Q animals. Moreover, a significant reduction (5.8%) in the total volume of the saccular otolith (which is responsible for sound detection) was observed in slc9a3r1 R180Q/R180Q compared to slc9a3r1 +/+ (P = 0.0014), while the utricular otolith, necessary for balance, was not affected in agreement with the human phenotype. Overall, these data strongly support the role of SLC9A3R1 gene in the pathogenesis of ARHL opening new perspectives in terms of diagnosis, prevention and treatment.
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Affiliation(s)
- Giorgia Girotto
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Anna Morgan
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Navaneethakrishnan Krishnamoorthy
- Sidra Medical and Research Center, Doha, Qatar.,Heart Science Centre, National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Massimiliano Cocca
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Marco Brumat
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Sissy Bassani
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Martina La Bianca
- Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Mariateresa Di Stazio
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
| | - Paolo Gasparini
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.,Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy
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4
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Lee C, Guinan JJ, Rutherford MA, Kaf WA, Kennedy KM, Buchman CA, Salt AN, Lichtenhan JT. Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region. J Neurophysiol 2019; 121:1018-1033. [PMID: 30673362 DOI: 10.1152/jn.00677.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve "tails," and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.
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Affiliation(s)
- C Lee
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - J J Guinan
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, and Department of Otolaryngology, Harvard Medical School , Boston, Massachusetts
| | - M A Rutherford
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - W A Kaf
- Communication Sciences and Disorders Department, Missouri State University , Springfield, Missouri
| | - K M Kennedy
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri.,Communication Sciences and Disorders Department, Missouri State University , Springfield, Missouri
| | - C A Buchman
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - A N Salt
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - J T Lichtenhan
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
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5
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Michel V, Booth KT, Patni P, Cortese M, Azaiez H, Bahloul A, Kahrizi K, Labbé M, Emptoz A, Lelli A, Dégardin J, Dupont T, Aghaie A, Oficjalska-Pham D, Picaud S, Najmabadi H, Smith RJ, Bowl MR, Brown SD, Avan P, Petit C, El-Amraoui A. CIB2, defective in isolated deafness, is key for auditory hair cell mechanotransduction and survival. EMBO Mol Med 2018; 9:1711-1731. [PMID: 29084757 PMCID: PMC5709726 DOI: 10.15252/emmm.201708087] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Defects of CIB2, calcium‐ and integrin‐binding protein 2, have been reported to cause isolated deafness, DFNB48 and Usher syndrome type‐IJ, characterized by congenital profound deafness, balance defects and blindness. We report here two new nonsense mutations (pGln12* and pTyr110*) in CIB2 patients displaying nonsyndromic profound hearing loss, with no evidence of vestibular or retinal dysfunction. Also, the generated CIB2−/− mice display an early onset profound deafness and have normal balance and retinal functions. In these mice, the mechanoelectrical transduction currents are totally abolished in the auditory hair cells, whilst they remain unchanged in the vestibular hair cells. The hair bundle morphological abnormalities of CIB2−/− mice, unlike those of mice defective for the other five known USH1 proteins, begin only after birth and lead to regression of the stereocilia and rapid hair‐cell death. This essential role of CIB2 in mechanotransduction and cell survival that, we show, is restricted to the cochlea, probably accounts for the presence in CIB2−/− mice and CIB2 patients, unlike in Usher syndrome, of isolated hearing loss without balance and vision deficits.
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Affiliation(s)
- Vincent Michel
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Kevin T Booth
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology- Head and Neck Surgery, University of Iowa, Iowa City, Iowa.,Department of Molecular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Pranav Patni
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Matteo Cortese
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Hela Azaiez
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology- Head and Neck Surgery, University of Iowa, Iowa City, Iowa
| | - Amel Bahloul
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Kimia Kahrizi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Ménélik Labbé
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Alice Emptoz
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Andrea Lelli
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Julie Dégardin
- Sorbonne Universités, UPMC Univ Paris06, Paris, France.,Retinal information processing - Pharmacology and Pathology, Institut de la Vision, Paris, France
| | - Typhaine Dupont
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Asadollah Aghaie
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France.,Syndrome de Usher et Autres Atteintes Rétino-Cochléaires, Institut de la Vision, Paris, France
| | - Danuta Oficjalska-Pham
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
| | - Serge Picaud
- Sorbonne Universités, UPMC Univ Paris06, Paris, France.,Retinal information processing - Pharmacology and Pathology, Institut de la Vision, Paris, France
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Richard J Smith
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology- Head and Neck Surgery, University of Iowa, Iowa City, Iowa
| | - Michael R Bowl
- Mammalian Genetics Unit, MRC Harwell Institute, Oxford, UK
| | | | - Paul Avan
- Laboratoire de Biophysique Sensorielle, Faculté de Médecine, Biophysique Médicale, Centre Jean Perrin, Université d'Auvergne, Clermont-Ferrand, France
| | - Christine Petit
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France.,Collège de France, Paris, France
| | - Aziz El-Amraoui
- Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France .,Unité Mixte de Recherche- UMRS 1120, Institut National de la Santé et de la Recherche Médicale, Paris, France.,Sorbonne Universités, UPMC Univ Paris06, Paris, France
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6
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Dulon D, Papal S, Patni P, Cortese M, Vincent PF, Tertrais M, Emptoz A, Tlili A, Bouleau Y, Michel V, Delmaghani S, Aghaie A, Pepermans E, Alegria-Prevot O, Akil O, Lustig L, Avan P, Safieddine S, Petit C, El-Amraoui A. Clarin-1 gene transfer rescues auditory synaptopathy in model of Usher syndrome. J Clin Invest 2018; 128:3382-3401. [PMID: 29985171 DOI: 10.1172/jci94351] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/17/2018] [Indexed: 11/17/2022] Open
Abstract
Clarin-1, a tetraspan-like membrane protein defective in Usher syndrome type IIIA (USH3A), is essential for hair bundle morphogenesis in auditory hair cells. We report a new synaptic role for clarin-1 in mouse auditory hair cells elucidated by characterization of Clrn1 total (Clrn1ex4-/-) and postnatal hair cell-specific conditional (Clrn1ex4fl/fl Myo15-Cre+/-) knockout mice. Clrn1ex4-/- mice were profoundly deaf, whereas Clrn1ex4fl/fl Myo15-Cre+/- mice displayed progressive increases in hearing thresholds, with, initially, normal otoacoustic emissions and hair bundle morphology. Inner hair cell (IHC) patch-clamp recordings for the 2 mutant mice revealed defective exocytosis and a disorganization of synaptic F-actin and CaV1.3 Ca2+ channels, indicative of a synaptopathy. Postsynaptic defects were also observed, with an abnormally broad distribution of AMPA receptors associated with a loss of afferent dendrites and defective electrically evoked auditory brainstem responses. Protein-protein interaction assays revealed interactions between clarin-1 and the synaptic CaV1.3 Ca2+ channel complex via the Cavβ2 auxiliary subunit and the PDZ domain-containing protein harmonin (defective in Usher syndrome type IC). Cochlear gene therapy in vivo, through adeno-associated virus-mediated Clrn1 transfer into hair cells, prevented the synaptic defects and durably improved hearing in Clrn1ex4fl/fl Myo15-Cre+/- mice. Our results identify clarin-1 as a key organizer of IHC ribbon synapses, and suggest new treatment possibilities for USH3A patients.
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Affiliation(s)
- Didier Dulon
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Université de Bordeaux, Laboratoire de Neurophysiologie de la Synapse Auditive, Bordeaux Neurocampus, Bordeaux, France
| | - Samantha Papal
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Pranav Patni
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Matteo Cortese
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Philippe Fy Vincent
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Université de Bordeaux, Laboratoire de Neurophysiologie de la Synapse Auditive, Bordeaux Neurocampus, Bordeaux, France
| | - Margot Tertrais
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Université de Bordeaux, Laboratoire de Neurophysiologie de la Synapse Auditive, Bordeaux Neurocampus, Bordeaux, France
| | - Alice Emptoz
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Abdelaziz Tlili
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Yohan Bouleau
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Université de Bordeaux, Laboratoire de Neurophysiologie de la Synapse Auditive, Bordeaux Neurocampus, Bordeaux, France
| | - Vincent Michel
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Sedigheh Delmaghani
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Alain Aghaie
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Elise Pepermans
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Olinda Alegria-Prevot
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
| | - Omar Akil
- Department of Otolaryngology-Head and Neck Surgery, UCSF, San Francisco, California, USA
| | - Lawrence Lustig
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Medical Center, New York, New York, USA
| | - Paul Avan
- Laboratoire de Biophysique Sensorielle, Faculté de Médecine, Université d'Auvergne; Biophysique Médicale, Centre Jean Perrin, Clermont-Ferrand, France
| | - Saaid Safieddine
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France.,Centre National de la Recherche Scientifique, Paris, France
| | - Christine Petit
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France.,Collège de France, Paris, France
| | - Aziz El-Amraoui
- UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France.,Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France.,Sorbonne Universités, Complexité du Vivant, Paris, France
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7
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Transient Abnormalities in Masking Tuning Curve in Early Progressive Hearing Loss Mouse Model. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6280969. [PMID: 29662891 PMCID: PMC5832037 DOI: 10.1155/2018/6280969] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/26/2017] [Indexed: 01/17/2023]
Abstract
Damage to cochlear outer hair cells (OHCs) usually affects frequency selectivity in proportion to hearing threshold increase. However, the current clinical heuristics that attributes poor hearing performance despite near-normal auditory sensitivity to auditory neuropathy or “hidden” synaptopathy overlooks possible underlying OHC impairment. Here, we document the part played by OHCs in influencing suprathreshold auditory performance in the presence of noise in a mouse model of progressive hair cell degeneration, the CD1 strain, at postnatal day 18–30 stages when high-frequency auditory thresholds remained near-normal. Nonetheless, total loss of high-frequency distortion product otoacoustic emissions pointed to nonfunctioning basal OHCs. This “discordant profile” came with a huge low-frequency shift of masking tuning curves that plot the level of interfering sound necessary to mask the response to a probe tone, against interfering frequency. Histology revealed intense OHC hair bundle abnormalities in the basal cochlea uncharacteristically associated with OHC survival and preserved coupling with the tectorial membrane. This pattern dismisses the superficial diagnosis of “hidden” neuropathy while underpinning a disorganization of cochlear frequency mapping with optimistic high-frequency auditory thresholds perhaps because responses to high frequencies are apically shifted. The audiometric advantage of frequency transposition is offset by enhanced masking by low-frequency sounds, a finding essential for guiding rehabilitation.
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8
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Hanada Y, Nakamura Y, Ishida Y, Takimoto Y, Taniguchi M, Ozono Y, Koyama Y, Morihana T, Imai T, Ota Y, Sato T, Inohara H, Shimada S. Epiphycan is specifically expressed in cochlear supporting cells and is necessary for normal hearing. Biochem Biophys Res Commun 2017; 492:379-385. [DOI: 10.1016/j.bbrc.2017.08.092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 08/23/2017] [Indexed: 12/12/2022]
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9
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Vogl C, Butola T, Haag N, Hausrat TJ, Leitner MG, Moutschen M, Lefèbvre PP, Speckmann C, Garrett L, Becker L, Fuchs H, Hrabe de Angelis M, Nietzsche S, Kessels MM, Oliver D, Kneussel M, Kilimann MW, Strenzke N. The BEACH protein LRBA is required for hair bundle maintenance in cochlear hair cells and for hearing. EMBO Rep 2017; 18:2015-2029. [PMID: 28893864 DOI: 10.15252/embr.201643689] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 07/27/2017] [Accepted: 08/07/2017] [Indexed: 12/15/2022] Open
Abstract
Lipopolysaccharide-responsive beige-like anchor protein (LRBA) belongs to the enigmatic class of BEACH domain-containing proteins, which have been attributed various cellular functions, typically involving intracellular protein and membrane transport processes. Here, we show that LRBA deficiency in mice leads to progressive sensorineural hearing loss. In LRBA knockout mice, inner and outer hair cell stereociliary bundles initially develop normally, but then partially degenerate during the second postnatal week. LRBA deficiency is associated with a reduced abundance of radixin and Nherf2, two adaptor proteins, which are important for the mechanical stability of the basal taper region of stereocilia. Our data suggest that due to the loss of structural integrity of the central parts of the hair bundle, the hair cell receptor potential is reduced, resulting in a loss of cochlear sensitivity and functional loss of the fraction of spiral ganglion neurons with low spontaneous firing rates. Clinical data obtained from two human patients with protein-truncating nonsense or frameshift mutations suggest that LRBA deficiency may likewise cause syndromic sensorineural hearing impairment in humans, albeit less severe than in our mouse model.
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Affiliation(s)
- Christian Vogl
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tanvi Butola
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Synaptic Nanophysiology Group, Max-Planck-Institute for Biophysical Chemistry Göttingen, Göttingen, Germany
| | - Natja Haag
- Institute for Biochemistry I, University Hospital Jena, Jena, Germany
| | - Torben J Hausrat
- Department for Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Michael G Leitner
- Department of Physiology, Philipps University Marburg, Marburg, Germany
| | - Michel Moutschen
- Department of Immunology and Infectious Diseases, University of Liège CHU Liège, Liège, Belgium
| | - Philippe P Lefèbvre
- Department of Otorhinolaryngology, University of Liège CHU Liège, Liège, Belgium
| | - Carsten Speckmann
- Division of Pediatric Hematology and Oncology, Center for Chronic Immunodeficiency and Department of Pediatrics and Adolescent Medicine, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lillian Garrett
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany.,Institute of Developmental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany
| | - Lore Becker
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany
| | - Helmut Fuchs
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München German Research Center for Environmental Health, Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, München, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | | | - Michael M Kessels
- Institute for Biochemistry I, University Hospital Jena, Jena, Germany
| | - Dominik Oliver
- Department of Physiology, Philipps University Marburg, Marburg, Germany
| | - Matthias Kneussel
- Department for Molecular Neurogenetics, Center for Molecular Neurobiology, ZMNH University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Manfred W Kilimann
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany.,Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Nicola Strenzke
- Auditory Systems Physiology Group Department of Otolaryngology University Medical Center Göttingen, Göttingen, Germany
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10
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Georgescu MM, Gagea M, Cote G. NHERF1/EBP50 Suppresses Wnt-β-Catenin Pathway-Driven Intestinal Neoplasia. Neoplasia 2017; 18:512-23. [PMID: 27566107 PMCID: PMC5018097 DOI: 10.1016/j.neo.2016.07.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 07/01/2016] [Accepted: 07/11/2016] [Indexed: 12/31/2022] Open
Abstract
NHERF1/EBP50, an adaptor molecule that interacts with β-catenin, YAP, and PTEN, has been recently implicated in the progression of various human malignancies, including colorectal cancer. We report here that NHERF1 acts as a tumor suppressor in vivo for intestinal adenoma development. NHERF1 is highly expressed at the apical membrane of mucosa intestinal epithelial cells (IECs) and serosa mesothelial cells. NHERF1-deficient mice show overall longer small intestine and colon that most likely could be attributed to a combination of defects, including altered apical brush border of absorbtive IECs and increased number of secretory IECs. NHERF1 deficiency in Apc(Min/+) mice resulted in significantly shorter animal survival due to markedly increased tumor burden. This resulted from a moderate increase of the overall tumor density, more pronounced in females than males, and a massive increase in the number of large adenomas in both genders. The analysis of possible pathways controlling tumor size showed upregulation of Wnt-β-catenin pathway, higher expression of unphosphorylated YAP, and prominent nuclear expression of cyclin D1 in NHERF1-deficient tumors. Similar YAP changes, with relative decrease of phosphorylated YAP and increase of nuclear YAP expression, were observed as early as the adenoma stages in the progression of human colorectal cancer. This study discusses a complex role of NHERF1 for intestinal morphology and presents indisputable evidence for its in vivo tumor suppressor function upstream of Wnt-β-catenin and Hippo-YAP pathways.
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Affiliation(s)
- Maria-Magdalena Georgescu
- Department of Pathology and Translational Pathobiology, Louisiana State University, Shreveport, LA, 71103, USA.
| | - Mihai Gagea
- Department of Veterinary Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Gilbert Cote
- Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
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11
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Callaway DJE, Matsui T, Weiss T, Stingaciu LR, Stanley CB, Heller WT, Bu Z. Controllable Activation of Nanoscale Dynamics in a Disordered Protein Alters Binding Kinetics. J Mol Biol 2017; 429:987-998. [PMID: 28285124 DOI: 10.1016/j.jmb.2017.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/04/2017] [Accepted: 03/02/2017] [Indexed: 01/03/2023]
Abstract
The phosphorylation of specific residues in a flexible disordered activation loop yields precise control of signal transduction. One paradigm is the phosphorylation of S339/S340 in the intrinsically disordered tail of the multi-domain scaffolding protein NHERF1, which affects the intracellular localization and trafficking of NHERF1 assembled signaling complexes. Using neutron spin echo spectroscopy (NSE), we show salt-concentration-dependent excitation of nanoscale motion at the tip of the C-terminal tail in the phosphomimic S339D/S340D mutant. The "tip of the whip" that is unleashed is near the S339/S340 phosphorylation site and flanks the hydrophobic Ezrin-binding motif. The kinetic association rate constant of the binding of the S339D/S340D mutant to the FERM domain of Ezrin is sensitive to buffer salt concentration, correlating with the excited nanoscale dynamics. The results suggest that electrostatics modulates the activation of nanoscale dynamics of an intrinsically disordered protein, controlling the binding kinetics of signaling partners. NSE can pinpoint the nanoscale dynamics changes in a highly specific manner.
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Affiliation(s)
- David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Thomas Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, CA 94025, USA
| | - Laura R Stingaciu
- Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Christopher B Stanley
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - William T Heller
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, CUNY, New York, NY 10031, USA.
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12
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Henkel B, Bintig W, Bhat SS, Spehr M, Neuhaus EM. NHERF1 in Microvilli of Vomeronasal Sensory Neurons. Chem Senses 2016; 42:25-35. [PMID: 27655939 DOI: 10.1093/chemse/bjw094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In most mammals, the vomeronasal system detects a variety of (semio)chemicals that mediate olfactory-driven social and sexual behaviors. Vomeronasal chemosensation depends on G protein-coupled receptors (V1R, V2R, and FPR-rs) that operate at remarkably low stimulus concentrations, thus, indicating a highly sensitive and efficient signaling pathway. We identified the PDZ domain-containing protein, Na+/H+ exchanger regulatory factor-1 (NHERF1), as putative molecular organizer of signal transduction in vomeronasal neurons. NHERF1 is a protein that contains 2 PDZ domains and a carboxy-terminal ezrin-binding domain. It localizes to microvilli of vomeronasal sensory neurons and interacts with V1Rs. Furthermore, NHERF1 and Gαi2 are closely colocalized. These findings open up new aspects of the functional organization and regulation of vomeronasal signal transduction by PDZ scaffolding proteins.
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Affiliation(s)
- Bastian Henkel
- Pharmacology and Toxicology, University Hospital Jena, Friedrich Schiller University Jena, Drackendorfer Straße 1, 07743 Jena, Germany.,Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany and.,Present address: Institute of Anatomy, Medical Faculty, University Duisburg-Essen, Hufelandstr. 55, 45147 Essen, Germany
| | - Willem Bintig
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany and.,Present address: Institute of Biochemistry, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - S Sneha Bhat
- Pharmacology and Toxicology, University Hospital Jena, Friedrich Schiller University Jena, Drackendorfer Straße 1, 07743 Jena, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Eva M Neuhaus
- Pharmacology and Toxicology, University Hospital Jena, Friedrich Schiller University Jena, Drackendorfer Straße 1, 07743 Jena, Germany, .,Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany and
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13
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Georgescu MM, Mobley BC, Orr BA, Shang P, Lehman NL, Zhu X, O’Neill TJ, Rajaram V, Hatanpaa KJ, Timmons CF, Raisanen JM. NHERF1/EBP50 and NF2 as diagnostic markers for choroid plexus tumors. Acta Neuropathol Commun 2016; 4:55. [PMID: 27229317 PMCID: PMC4882843 DOI: 10.1186/s40478-016-0329-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/21/2016] [Indexed: 11/10/2022] Open
Abstract
The adaptor protein NHERF1 (Na/H exchanger-3 regulatory factor-1) and its associated ezrin-radixin-moesin-merlin/neurofibromin-2 (ERM-NF2) family proteins are required for epithelial morphogenesis and have been implicated in cancer progression. NHERF1 is expressed in ependymal cells and constitutes a highly sensitive diagnostic marker for ependymoma, where it labels membrane polarity structures. Since NHERF1 and ERM-NF2 proteins show polarized expression in choroid plexus (CP) cells, we tested their diagnostic utility in CP neoplasms. NHERF1 immunohistochemistry in 43 adult and pediatric tumors with papillary morphology revealed strong apical plasma membrane staining in CP papilloma (WHO grade I) and cytoplasmic expression in CP carcinoma (WHO grade III). Ezrin and moesin showed similar but less distinctive staining. NHERF1 also labeled papillary tumors of the pineal region in a microlumen and focal apical membrane pattern, suggestive of a transitional morphology between CP papilloma and ependymoma. CP tumors of all grades could be differentiated from metastatic carcinomas with papillary architecture by NF2, which showed polarized membranous staining in CP tumors. NHERF1 and NF2 immunohistochemistry showed enhanced sensitivity and specificity for CP tumors compared to commonly used markers, including cytokeratins and Kir7.1, emerging as reliable diagnostic tools for the differential diagnosis of papillary tumors of the central nervous system.
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14
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Lu X, Sipe CW. Developmental regulation of planar cell polarity and hair-bundle morphogenesis in auditory hair cells: lessons from human and mouse genetics. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 5:85-101. [PMID: 26265594 DOI: 10.1002/wdev.202] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/12/2015] [Accepted: 06/29/2015] [Indexed: 12/11/2022]
Abstract
Hearing loss is the most common and costly sensory defect in humans and genetic causes underlie a significant proportion of affected individuals. In mammals, sound is detected by hair cells (HCs) housed in the cochlea of the inner ear, whose function depends on a highly specialized mechanotransduction organelle, the hair bundle. Understanding the factors that regulate the development and functional maturation of the hair bundle is crucial for understanding the pathophysiology of human deafness. Genetic analysis of deafness genes in animal models, together with complementary forward genetic screens and conditional knock-out mutations in essential genes, have provided great insights into the molecular machinery underpinning hair-bundle development and function. In this review, we highlight recent advances in our understanding of hair-bundle morphogenesis, with an emphasis on the molecular pathways governing hair-bundle polarity and orientation. We next discuss the proteins and structural elements important for hair-cell mechanotransduction as well as hair-bundle cohesion and maintenance. In addition, developmental signals thought to regulate tonotopic features of HCs are introduced. Finally, novel approaches that complement classic genetics for studying the molecular etiology of human deafness are presented. WIREs Dev Biol 2016, 5:85-101. doi: 10.1002/wdev.202 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Xiaowei Lu
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Conor W Sipe
- Department of Biology, University of Virginia, Charlottesville, VA, USA
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15
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NHERF1/EBP50 is an organizer of polarity structures and a diagnostic marker in ependymoma. Acta Neuropathol Commun 2015; 3:11. [PMID: 25775275 PMCID: PMC4352254 DOI: 10.1186/s40478-015-0197-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 02/18/2015] [Indexed: 12/01/2022] Open
Abstract
NHERF1/EBP50, an adaptor protein required for epithelial morphogenesis, has been implicated in the progression of various human malignancies. NHERF1-deficient mice have intestinal brush border structural defects and we report here that they also have disorganized ependymal cilia with development of non-obstructive hydrocephalus. Examination of mouse and human brain tissues revealed highest NHERF1 expression at the apical plasma membrane of ependymal cells. In ependymal tumors, NHERF1 expression was retained in polarized membrane structures, such as microlumens, rosettes and canals, where it co-localized with some of its ligands, such as moesin and PTEN. Analysis of a comprehensive panel of 113 tumors showed robust NHERF1 labeling of microlumens in 100% of ependymomas, subependymomas, and pediatric anaplastic ependymomas, and in 67% of adult anaplastic ependymomas. NHERF1 staining was present in 35% of ependymoma cases that lacked reactivity for EMA, the routine immunohistochemical marker used for ependymoma diagnosis. NHERF1 labeling of microlumens was either absent or rarely seen in other types of brain tumors analyzed, denoting NHERF1 as a reliable diagnostic marker of ependymal tumors. Anaplastic foci and a subset of adult anaplastic ependymomas showed complete absence of NHERF1-labeled polarity structures, consistent with a loss of differentiation in these aggressive tumors. These data highlight a role for NHERF1 in ependymal morphogenesis with direct application to the diagnosis of ependymal tumors.
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16
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Genetics of auditory mechano-electrical transduction. Pflugers Arch 2014; 467:49-72. [PMID: 24957570 PMCID: PMC4281357 DOI: 10.1007/s00424-014-1552-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 12/29/2022]
Abstract
The hair bundles of cochlear hair cells play a central role in the auditory mechano-electrical transduction (MET) process. The identification of MET components and of associated molecular complexes by biochemical approaches is impeded by the very small number of hair cells within the cochlea. In contrast, human and mouse genetics have proven to be particularly powerful. The study of inherited forms of deafness led to the discovery of several essential proteins of the MET machinery, which are currently used as entry points to decipher the associated molecular networks. Notably, MET relies not only on the MET machinery but also on several elements ensuring the proper sound-induced oscillation of the hair bundle or the ionic environment necessary to drive the MET current. Here, we review the most significant advances in the molecular bases of the MET process that emerged from the genetics of hearing.
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