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Loss of Myh14 Increases Susceptibility to Noise-Induced Hearing Loss in CBA/CaJ Mice. Neural Plast 2016; 2016:6720420. [PMID: 28101381 PMCID: PMC5215640 DOI: 10.1155/2016/6720420] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 10/08/2016] [Accepted: 11/07/2016] [Indexed: 01/24/2023] Open
Abstract
MYH14 is a member of the myosin family, which has been implicated in many motile processes such as ion-channel gating, organelle translocation, and the cytoskeleton rearrangement. Mutations in MYH14 lead to a DFNA4-type hearing impairment. Further evidence also shows that MYH14 is a candidate noise-induced hearing loss (NIHL) susceptible gene. However, the specific roles of MYH14 in auditory function and NIHL are not fully understood. In the present study, we used CRISPR/Cas9 technology to establish a Myh14 knockout mice line in CBA/CaJ background (now referred to as Myh14−/− mice) and clarify the role of MYH14 in the cochlea and NIHL. We found that Myh14−/− mice did not exhibit significant hearing loss until five months of age. In addition, Myh14−/− mice were more vulnerable to high intensity noise compared to control mice. More significant outer hair cell loss was observed in Myh14−/− mice than in wild type controls after acoustic trauma. Our findings suggest that Myh14 may play a beneficial role in the protection of the cochlea after acoustic overstimulation in CBA/CaJ mice.
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Reinhold AK, Rittner HL. Barrier function in the peripheral and central nervous system-a review. Pflugers Arch 2016; 469:123-134. [PMID: 27957611 DOI: 10.1007/s00424-016-1920-8] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/23/2016] [Accepted: 11/27/2016] [Indexed: 11/29/2022]
Abstract
The peripheral (PNS) and central nervous system (CNS) are delicate structures, highly sensitive to homeostatic changes-and crucial for basic vital functions. Thus, a selection of barriers ensures the protection of the nervous system from noxious blood-borne or surrounding stimuli. In this chapter, anatomy and functioning of the blood-nerve (BNB), the blood-brain (BBB), and the blood-spinal cord barriers (BSCB) are presented and the key tight junction (TJ) proteins described: claudin-1, claudin-3, claudin-5, claudin-11, claudin-12, claudin-19, occludin, Zona occludens-1 (ZO-1), and tricellulin are by now identified as relevant for nerval barriers. Different diseases can lead to or be accompanied by neural barrier disruption, and impairment of these barriers worsens pathology. Peripheral nerve injury and inflammatory polyneuropathy cause an increased permeability of BNB as well as BSCB, while, e.g., diseases of the CNS such as amyotrophic lateral sclerosis, multiple sclerosis, spinal cord injury, or Alzheimer's disease can progress and worsen through barrier dysfunction. Moreover, the complex role and regulation of the BBB after ischemic stroke is described. On the other side, PNS and CNS barriers hamper the delivery of drugs in diseases when the barrier is intact, e.g., in certain neurodegenerative diseases or inflammatory pain. Understanding of the barrier - regulating processes has already lead to the discovery of new molecules as drug enhancers. In summary, the knowledge of all of these mechanisms might ultimately lead to the invention of drugs to control barrier function to help ameliorating or curing neurological diseases.
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Affiliation(s)
- A K Reinhold
- Department of Anesthesiology, University Hospitals Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany.
| | - H L Rittner
- Department of Anesthesiology, University Hospitals Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany
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Spatial integration of E-cadherin adhesion, signalling and the epithelial cytoskeleton. Curr Opin Cell Biol 2016; 42:138-145. [DOI: 10.1016/j.ceb.2016.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/22/2016] [Accepted: 07/08/2016] [Indexed: 12/18/2022]
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Zhou L, Gong Y, Sunq A, Hou J, Baker LA. Capturing Rare Conductance in Epithelia with Potentiometric-Scanning Ion Conductance Microscopy. Anal Chem 2016; 88:9630-9637. [DOI: 10.1021/acs.analchem.6b02392] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Lushan Zhou
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Yongfeng Gong
- Renal
Division, Washington University Medical School, 660 South Euclid
Avenue, St. Louis, Missouri 63110, United States
| | - Abby Sunq
- Renal
Division, Washington University Medical School, 660 South Euclid
Avenue, St. Louis, Missouri 63110, United States
| | - Jianghui Hou
- Renal
Division, Washington University Medical School, 660 South Euclid
Avenue, St. Louis, Missouri 63110, United States
- Center
for Investigation of Membrane Excitability Diseases, Washington University Medical School, 660 South Euclid Avenue, St. Louis, Missouri 63110, United States
| | - Lane A. Baker
- Department
of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405, United States
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Tricellular Tight Junctions in the Inner Ear. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6137541. [PMID: 27195292 PMCID: PMC4852330 DOI: 10.1155/2016/6137541] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 04/03/2016] [Indexed: 11/26/2022]
Abstract
Tight junctions (TJs) are structures that seal the space between the epithelial cell sheets. In the inner ear, the barrier function of TJs is indispensable for the separation of the endolymphatic and perilymphatic spaces, which is essential for the generation and maintenance of the endocochlear potential (EP). TJs are formed by the intercellular binding of membrane proteins, known as claudins, and mutations in these proteins cause deafness in humans and mice. Within the epithelial cell sheet, however, a bound structure is present at the site where the corners of three cells meet (tricellular tight junctions (tTJs)), and the maintenance of the barrier function at this location cannot be explained by the claudins alone. Tricellulin and the angulin family of proteins (angulin-1/LSR, angulin-2/ILDR1, and angulin-3/ILDR2) have been identified as tTJ-associated proteins. Tricellulin and ILDR1 are localized at the tTJ and alterations in these proteins have been reported to be involved in deafness. In this review, we will present the current state of knowledge for tTJs.
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Ohlemiller KK, Kiener AL, Gagnon PM. QTL Mapping of Endocochlear Potential Differences between C57BL/6J and BALB/cJ mice. J Assoc Res Otolaryngol 2016; 17:173-94. [PMID: 26980469 DOI: 10.1007/s10162-016-0558-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 02/25/2016] [Indexed: 12/18/2022] Open
Abstract
We reported earlier that the endocochlear potential (EP) differs between C57BL/6J (B6) and BALB/cJ (BALB) mice, being lower in BALBs by about 10 mV (Ohlemiller et al. Hear Res 220: 10-26, 2006). This difference corresponds to strain differences with respect to the density of marginal cells in cochlear stria vascularis. After about 1 year of age, BALB mice also tend toward EP reduction that correlates with further marginal cell loss. We therefore suggested that early sub-clinical features of the BALB stria vascularis may predispose these mice to a condition modeling Schuknecht's strial presbycusis. We further reported (Ohlemiller et al. J Assoc Res Otolaryngol 12: 45-58, 2011) that the acute effects of a 2-h 110 dB SPL noise exposure differ between B6 and BALB mice, such that the EP remains unchanged in B6 mice, but is reduced by 40-50 mV in BALBs. In about 25 % of BALBs, the EP does not completely recover, so that permanent EP reduction may contribute to noise-induced permanent threshold shifts in BALBs. To identify genes and alleles that may promote natural EP variation as well as noise-related EP reduction in BALB mice, we have mapped related quantitative trait loci (QTLs) using 12 recombinant inbred (RI) strains formed from B6 and BALB (CxB1-CxB12). EP and strial marginal cell density were measured in B6 mice, BALB mice, their F1 hybrids, and RI mice without noise exposure, and 1-3 h after broadband noise (4-45 kHz, 110 dB SPL, 2 h). For unexposed mice, the strain distribution patterns for EP and marginal cell density were used to generate preliminary QTL maps for both EP and marginal cell density. Six QTL regions were at least statistically suggestive, including a significant QTL for marginal cell density on chromosome 12 that overlapped a weak QTL for EP variation. This region, termed Maced (Marginal cell density QTL) supports the notion of marginal cell density as a genetically influenced contributor to natural EP variation. Candidate genes for Maced notably include Foxg1, Foxa1, Akap6, Nkx2-1, and Pax9. Noise exposure produced significant EP reductions in two RI strains as well as significant EP increases in two RI strains. QTL mapping of the EP in noise-exposed RI mice yielded four suggestive regions. Two of these overlapped with QTL regions we previously identified for noise-related EP reduction in CBA/J mice (Ohlemiller et al. Hear Res 260: 47-53, 2010) on chromosomes 5 and 18 (Nirep). The present map may narrow the Nirep interval to a ~10-Mb region of proximal Chr. 18 that includes Zeb1, Arhgap12, Mpp7, and Gjd4. This study marks the first exploration of natural gene variants that modulate the EP. Their orthologs may underlie some human hearing loss that originates in the lateral wall.
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Affiliation(s)
- Kevin K Ohlemiller
- Department of Otolaryngology, Central Institute for the Deaf at Washington University School of Medicine, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, St. Louis, MO, 63110, USA.
| | - Anna L Kiener
- Department of Speech and Hearing Science, Ohio State University, Columbus, OH, USA
| | - Patricia M Gagnon
- Department of Otolaryngology, Central Institute for the Deaf at Washington University School of Medicine, Fay and Carl Simons Center for Hearing and Deafness, Washington University School of Medicine, 660 S. Euclid, St. Louis, MO, 63110, USA
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Abstract
UNLABELLED Disordered protein ubiquitination has been linked to neurodegenerative disease, yet its role in inner ear homeostasis and hearing loss is essentially unknown. Here we show that progressive hearing loss in the ethylnitrosourea-generated mambo mouse line is caused by a mutation in Usp53, a member of the deubiquitinating enzyme family. USP53 contains a catalytically inactive ubiquitin-specific protease domain and is expressed in cochlear hair cells and a subset of supporting cells. Although hair cell differentiation is unaffected in mambo mice, outer hair cells degenerate rapidly after the first postnatal week. USP53 colocalizes and interacts with the tight junction scaffolding proteins TJP1 and TJP2 in polarized epithelial cells, suggesting that USP53 is part of the tight junction complex. The barrier properties of tight junctions of the stria vascularis appeared intact in a biotin tracer assay, but the endocochlear potential is reduced in adult mambo mice. Hair cell degeneration in mambo mice precedes endocochlear potential decline and is rescued in cochlear organotypic cultures in low potassium milieu, indicating that hair cell loss is triggered by extracellular factors. Remarkably, heterozygous mambo mice show increased susceptibility to noise injury at high frequencies. We conclude that USP53 is a novel tight junction-associated protein that is essential for the survival of auditory hair cells and normal hearing in mice, possibly by modulating the barrier properties and mechanical stability of tight junctions. SIGNIFICANCE STATEMENT Hereditary hearing loss is extremely prevalent in the human population, but many genes linked to hearing loss remain to be discovered. Forward genetics screens in mice have facilitated the identification of genes involved in sensory perception and provided valuable animal models for hearing loss in humans. This involves introducing random mutations in mice, screening the mice for hearing defects, and mapping the causative mutation. Here, we have identified a mutation in the Usp53 gene that causes progressive hearing loss in the mambo mouse line. We demonstrate that USP53 is a catalytically inactive deubiquitinating enzyme and a novel component of tight junctions that is necessary for sensory hair cell survival and inner ear homeostasis.
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Deletion of Tricellulin Causes Progressive Hearing Loss Associated with Degeneration of Cochlear Hair Cells. Sci Rep 2015; 5:18402. [PMID: 26677943 PMCID: PMC4683410 DOI: 10.1038/srep18402] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 11/17/2015] [Indexed: 12/20/2022] Open
Abstract
Tricellulin (also known as MARVELD2) is considered as a central component of tricellular tight junctions and is distributed among various epithelial tissues. Although mutations in the gene encoding tricellulin are known to cause deafness in humans (DFNB49) and mice, the influence of its systemic deletion in vivo remains unknown. When we generated tricellulin-knockout mice (Tric−/−), we found an early-onset rapidly progressive hearing loss associated with the degeneration of hair cells (HCs); however, their body size and overall appearance were normal. Tric−/− mice did not show any morphological change pertaining to other organs such as the gastrointestinal tract, liver, kidney, thyroid gland and heart. The endocochlear potential (EP) was normal in Tric−/− mice, suggesting that the tight junction barrier is maintained in the stria vascularis, where EP is generated. The degeneration of HCs, which occurred after the maturation of EP, was prevented in the culture medium with an ion concentration similar to that of the perilymph. These data demonstrate the specific requirement of tricellulin for maintaining ion homeostasis around cochlear HCs to ensure their survival. The Tric−/− mouse provides a new model for understanding the distinct roles of tricellulin in different epithelial systems as well as in the pathogenesis of DFNB49.
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Yousaf R, Meng Q, Hufnagel RB, Xia Y, Puligilla C, Ahmed ZM, Riazuddin S. MAP3K1 function is essential for cytoarchitecture of the mouse organ of Corti and survival of auditory hair cells. Dis Model Mech 2015; 8:1543-53. [PMID: 26496772 PMCID: PMC4728323 DOI: 10.1242/dmm.023077] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/16/2015] [Indexed: 12/11/2022] Open
Abstract
MAP3K1 is a serine/threonine kinase that is activated by a diverse set of stimuli and exerts its effect through various downstream effecter molecules, including JNK, ERK1/2 and p38. In humans, mutant alleles of MAP3K1 are associated with 46,XY sex reversal. Until recently, the only phenotype observed in Map3k1tm1Yxia mutant mice was open eyelids at birth. Here, we report that homozygous Map3k1tm1Yxia mice have early-onset profound hearing loss accompanied by the progressive degeneration of cochlear outer hair cells. In the mouse inner ear, MAP3K1 has punctate localization at the apical surface of the supporting cells in close proximity to basal bodies. Although the cytoarchitecture, neuronal wiring and synaptic junctions in the organ of Corti are grossly preserved, Map3k1tm1Yxia mutant mice have supernumerary functional outer hair cells (OHCs) and Deiters' cells. Loss of MAP3K1 function resulted in the downregulation of Fgfr3, Fgf8, Fgf10 and Atf3 expression in the inner ear. Fgfr3, Fgf8 and Fgf10 have a role in induction of the otic placode or in otic epithelium development in mice, and their functional deficits cause defects in cochlear morphogenesis and hearing loss. Our studies suggest that MAP3K1 has an essential role in the regulation of these key cochlear morphogenesis genes. Collectively, our data highlight the crucial role of MAP3K1 in the development and function of the mouse inner ear and hearing. Summary:Map3k1 mutant mice exhibit early-onset profound hearing loss and supernumerary outer hair cells, along with dysregulation of the FGF signaling pathway, accentuating its function in otic epithelium development and morphogenesis.
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Affiliation(s)
- Rizwan Yousaf
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Qinghang Meng
- Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Robert B Hufnagel
- Divisions of Pediatric Ophthalmology and Human Genetics, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Ying Xia
- Department of Environmental Health, University of Cincinnati, College of Medicine, Cincinnati, OH 45267, USA
| | - Chandrakala Puligilla
- Department of Pathology & Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Zubair M Ahmed
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21201, USA
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Mruk DD, Cheng CY. The Mammalian Blood-Testis Barrier: Its Biology and Regulation. Endocr Rev 2015; 36:564-91. [PMID: 26357922 PMCID: PMC4591527 DOI: 10.1210/er.2014-1101] [Citation(s) in RCA: 400] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 09/03/2015] [Indexed: 12/31/2022]
Abstract
Spermatogenesis is the cellular process by which spermatogonia develop into mature spermatids within seminiferous tubules, the functional unit of the mammalian testis, under the structural and nutritional support of Sertoli cells and the precise regulation of endocrine factors. As germ cells develop, they traverse the seminiferous epithelium, a process that involves restructuring of Sertoli-germ cell junctions, as well as Sertoli-Sertoli cell junctions at the blood-testis barrier. The blood-testis barrier, one of the tightest tissue barriers in the mammalian body, divides the seminiferous epithelium into 2 compartments, basal and adluminal. The blood-testis barrier is different from most other tissue barriers in that it is not only comprised of tight junctions. Instead, tight junctions coexist and cofunction with ectoplasmic specializations, desmosomes, and gap junctions to create a unique microenvironment for the completion of meiosis and the subsequent development of spermatids into spermatozoa via spermiogenesis. Studies from the past decade or so have identified the key structural, scaffolding, and signaling proteins of the blood-testis barrier. More recent studies have defined the regulatory mechanisms that underlie blood-testis barrier function. We review here the biology and regulation of the mammalian blood-testis barrier and highlight research areas that should be expanded in future studies.
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Affiliation(s)
- Dolores D Mruk
- Center for Biomedical Research, Population Council, New York, New York 10065
| | - C Yan Cheng
- Center for Biomedical Research, Population Council, New York, New York 10065
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Mašindová I, Šoltýsová A, Varga L, Mátyás P, Ficek A, Hučková M, Sůrová M, Šafka-Brožková D, Anwar S, Bene J, Straka S, Janicsek I, Ahmed ZM, Seeman P, Melegh B, Profant M, Klimeš I, Riazuddin S, Kádasi Ľ, Gašperíková D. MARVELD2 (DFNB49) mutations in the hearing impaired Central European Roma population--prevalence, clinical impact and the common origin. PLoS One 2015; 10:e0124232. [PMID: 25885414 PMCID: PMC4401708 DOI: 10.1371/journal.pone.0124232] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 02/27/2015] [Indexed: 01/26/2023] Open
Abstract
Background In the present study we aimed: 1) To establish the prevalence and clinical impact of DFNB49 mutations in deaf Roma from 2 Central European countries (Slovakia and Hungary), and 2) to analyze a possible common origin of the c.1331+2T>C mutation among Roma and Pakistani mutation carriers identified in the present and previous studies. Methods We sequenced 6 exons of the MARVELD2 gene in a group of 143 unrelated hearing impaired Slovak Roma patients. Simultaneously, we used RFLP to detect the c.1331+2T>C mutation in 85 Hungarian deaf Roma patients, control groups of 702 normal hearing Romanies from both countries and 375 hearing impaired Slovak Caucasians. We analyzed the haplotype using 21 SNPs spanning a 5.34Mb around the mutation c.1331+2T>C. Results One pathogenic mutation (c.1331+2T>C) was identified in 12 homozygous hearing impaired Roma patients. Allele frequency of this mutation was higher in Hungarian (10%) than in Slovak (3.85%) Roma patients. The identified common haplotype in Roma patients was defined by 18 SNP markers (3.89 Mb). Fourteen common SNPs were also shared among Pakistani and Roma homozygotes. Biallelic mutation carriers suffered from prelingual bilateral moderate to profound sensorineural hearing loss. Conclusions We demonstrate different frequencies of the c.1331+2T>C mutation in hearing impaired Romanies from 3 Central European countries. In addition, our results provide support for the hypothesis of a possible common ancestor of the Slovak, Hungarian and Czech Roma as well as Pakistani deaf patients. Testing for the c.1331+2T>C mutation may be recommended in GJB2 negative Roma cases with early-onset sensorineural hearing loss.
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Affiliation(s)
- Ivica Mašindová
- Laboratory of Diabetes and Metabolic Disorders & DIABGENE, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Andrea Šoltýsová
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
- Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Lukáš Varga
- Laboratory of Diabetes and Metabolic Disorders & DIABGENE, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
- Department of Otorhinolaryngology—Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia
| | - Petra Mátyás
- Department of Medical Genetics, University of Pécs, Clinical Centre, Pécs, Hungary
| | - Andrej Ficek
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Miloslava Hučková
- Laboratory of Diabetes and Metabolic Disorders & DIABGENE, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
- Center for Molecular Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Martina Sůrová
- Laboratory of Diabetes and Metabolic Disorders & DIABGENE, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Dana Šafka-Brožková
- DNA Laboratory, Department of Paediatric Neurology, Charles University 2nd Medical School and University Hospital Motol, Prague, Czech Republic
| | - Saima Anwar
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Judit Bene
- Department of Medical Genetics, University of Pécs, Clinical Centre, Pécs, Hungary
- Szentagothai Research Centre, University of Pécs, Pécs, Hungary
| | - Slavomír Straka
- Department of Otorhinolaryngology—Head and Neck Surgery, Faculty Hospital of J. A. Reiman, Prešov, Slovakia
| | - Ingrid Janicsek
- Department of Medical Genetics, University of Pécs, Clinical Centre, Pécs, Hungary
| | - Zubair M. Ahmed
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Pavel Seeman
- DNA Laboratory, Department of Paediatric Neurology, Charles University 2nd Medical School and University Hospital Motol, Prague, Czech Republic
| | - Béla Melegh
- Department of Medical Genetics, University of Pécs, Clinical Centre, Pécs, Hungary
- Szentagothai Research Centre, University of Pécs, Pécs, Hungary
| | - Milan Profant
- Department of Otorhinolaryngology—Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia
| | - Iwar Klimeš
- Laboratory of Diabetes and Metabolic Disorders & DIABGENE, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Ľudevít Kádasi
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
- Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Daniela Gašperíková
- Laboratory of Diabetes and Metabolic Disorders & DIABGENE, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
- Center for Molecular Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
- * E-mail:
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Nayak G, Varga L, Trincot C, Shahzad M, Friedman PL, Klimes I, Greinwald JH, Riazuddin SA, Masindova I, Profant M, Khan SN, Friedman TB, Ahmed ZM, Gasperikova D, Riazuddin S, Riazuddin S. Molecular genetics of MARVELD2 and clinical phenotype in Pakistani and Slovak families segregating DFNB49 hearing loss. Hum Genet 2015; 134:423-37. [PMID: 25666562 PMCID: PMC4561550 DOI: 10.1007/s00439-015-1532-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 01/29/2015] [Indexed: 11/24/2022]
Abstract
Pathogenic mutations of MARVELD2, encoding tricellulin, a tricelluar tight junction protein, cause autosomal recessive non-syndromic hearing loss (DFNB49) in families of Pakistan and Czech Roma origin. In fact, they are a significant cause of prelingual hearing loss in the Czech Roma, second only to GJB2 variants. Previously, we reported that mice homozygous for p.Arg497* variant of Marveld2 had a broad phenotypic spectrum, where defects were observed in the inner ear, heart, mandibular salivary gland, thyroid gland and olfactory epithelium. The current study describes the types and frequencies of MARVELD2 alleles and clinically reexamines members of DFNB49 families. We found that MARVELD2 variants are responsible for about 1.5 % (95 % CI 0.8-2.6) of non-syndromic hearing loss in our cohort of 800 Pakistani families. The c.1331+2T>C allele is recurrent. In addition, we identified a novel large deletion in a single family, which appears to have resulted from non-allelic homologous recombination between two similar Alu short interspersed elements. Finally, we observed no other clinical manifestations co-segregating with hearing loss in DFNB49 human families, and hypothesize that the additional abnormalities in the Marveld2 mutant mouse indicates a critical non-redundant function for tricellulin in other organ systems.
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Affiliation(s)
- Gowri Nayak
- Division of Pediatric Otolaryngology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Lukas Varga
- Department of Otorhinolaryngology Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia
- Diabgene, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Claire Trincot
- Division of Pediatric Otolaryngology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Mohsin Shahzad
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21203, USA
| | - Penelope L. Friedman
- Internal Medicine Consult Service, Hatfield Clinical Research Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Iwar Klimes
- Diabgene, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - John H. Greinwald
- Division of Pediatric Otolaryngology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - S Amer Riazuddin
- National Center of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ivica Masindova
- Diabgene, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Milan Profant
- Department of Otorhinolaryngology Head and Neck Surgery, Faculty of Medicine and University Hospital, Comenius University, Bratislava, Slovakia
| | - Shaheen N. Khan
- National Center of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, Porter Neuroscience Research Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zubair M. Ahmed
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21203, USA
| | - Daniela Gasperikova
- Diabgene, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
- Centre for Molecular Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Sheikh Riazuddin
- Allama Iqbal Medical College-Jinnah Hospital Complex, University of Health Sciences, Lahore, Pakistan
- University of Lahore, Raiwind Road, Lahore, Pakistan
| | - Saima Riazuddin
- Department of Otorhinolaryngology Head and Neck Surgery, School of Medicine, University of Maryland, Baltimore, MD 21203, USA
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Higashi T, Katsuno T, Kitajiri SI, Furuse M. Deficiency of angulin-2/ILDR1, a tricellular tight junction-associated membrane protein, causes deafness with cochlear hair cell degeneration in mice. PLoS One 2015; 10:e0120674. [PMID: 25822906 PMCID: PMC4378975 DOI: 10.1371/journal.pone.0120674] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 02/05/2015] [Indexed: 11/18/2022] Open
Abstract
Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the vertices of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and tricellulin have been reported to cause human hereditary deafness DFNB42 and DFNB49, respectively. To investigate the pathogenesis of DFNB42, we analyzed mice with a targeted disruption of Ildr1, which encodes angulin-2/ILDR1. Ildr1 null mice exhibited profound deafness. Hair cells in the cochlea of Ildr1 null mice develop normally, but begin to degenerate by two weeks after birth. Tricellulin localization at tricellular contacts of the organ of Corti in the cochlea was retained in Ildr1 null mice, but its distribution along the depth of tricellular contacts was affected. Interestingly, compensatory tricellular contact localization of angulin-1/LSR was observed in the organ of Corti in Ildr1 null mice although it was hardly detected in the organ of Corti in wild-type mice. The onset of hair cell degeneration in Ildr1 null mice was earlier than that in the reported Tric mutant mice, which mimic one of the tricellulin mutations in DFNB49 deafness. These results indicate that the angulin-2/ILDR1 deficiency causes the postnatal degenerative loss of hair cells in the cochlea, leading to human deafness DFNB42. Our data also suggest that angulin family proteins have distinct functions in addition to their common roles of tricellulin recruitment and that the function of angulin-2/ILDR1 for hearing cannot be substituted by angulin-1/LSR.
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Affiliation(s)
- Tomohito Higashi
- Division of Cell Biology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tatsuya Katsuno
- Department of Otolaryngology—Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shin-ichiro Kitajiri
- Department of Otolaryngology—Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- * E-mail: (SK); (MF)
| | - Mikio Furuse
- Division of Cell Biology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
- Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, Japan
- * E-mail: (SK); (MF)
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64
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Sang Q, Li W, Xu Y, Qu R, Xu Z, Feng R, Jin L, He L, Li H, Wang L. ILDR1 deficiency causes degeneration of cochlear outer hair cells and disrupts the structure of the organ of Corti: a mouse model for human DFNB42. Biol Open 2015; 4:411-8. [PMID: 25819842 PMCID: PMC4400585 DOI: 10.1242/bio.201410876] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Immunoglobulin-like domain containing receptor 1 (ILDR1) is a poorly characterized gene that was first identified in lymphoma cells. Mutations in ILDR1 are responsible for DFNB42, but the pathogenesis of hearing loss caused by ILDR1 mutations remains to be elucidated. To explore the role of ILDR1 in hearing, we created Ildr1 knockout mice. In heterozygous mice, ILDR1 expression was found in outer hair cells (OHCs) and inner hair cells (IHCs) of the organ of Corti. ILDR1-deficient mice are profoundly deaf by postnatal day 21 (P21). No significant difference was observed in the supporting cells and IHCs of ILDR1-deficient mice, but progressive degeneration of OHCs occurred at P15 and disruption of the tunnel running through the organ of Corti was noticeable at P21. By P28, there were no OHCs visible in any of the turns of the organ of Corti, and the tunnel of the organ of Corti was entirely destroyed. ILDR1 deficiency affects expression of tricellulin in vivo, and this provides a possible explanation to hearing loss. To further elucidate the mechanism of deafness related to ILDR1 deficiency, we pursued a differential proteomic approach to comprehensively assess differential protein expression in the cochleae of Ildr1+/− and Ildr1−/− mice at P21. Altogether, 708 proteins were up-regulated (fold change >1.5) and 114 proteins were down-regulated (fold change <0.5) in the Ildr1−/− mice compared with Ildr1+/− mice. Gene ontology classification indicated that a number of differentially expressed proteins are involved in cell adhesion, protein and vesicle-mediated transport, cell death, membrane organization, and cellular homeostasis. A few of these proteins are closely related to hearing development. Taken together, our data suggest that ILDR1 is important for the survival of OHCs and provide novel insights into the pathogenesis of human deafness DFNB42 deafness.
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Affiliation(s)
- Qing Sang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200032, PR China Institute of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai, 200032, PR China
| | - Wen Li
- Department of Otolaryngology, Eye & ENT hospital, Fudan University, 83 Fenyang Road, Shanghai, 200031, PR China
| | - Yao Xu
- Institute of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai, 200032, PR China
| | - Ronggui Qu
- Institute of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai, 200032, PR China
| | - Zhigang Xu
- School of Life Sciences, Shandong University, Shandong, China
| | - Ruizhi Feng
- Institute of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai, 200032, PR China
| | - Li Jin
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200032, PR China
| | - Lin He
- Institute of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai, 200032, PR China Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, 200030, PR China
| | - Huawei Li
- Department of Otolaryngology, Eye & ENT hospital, Fudan University, 83 Fenyang Road, Shanghai, 200031, PR China
| | - Lei Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, 200032, PR China Institute of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai, 200032, PR China
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65
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Nishio SY, Hattori M, Moteki H, Tsukada K, Miyagawa M, Naito T, Yoshimura H, Iwasa YI, Mori K, Shima Y, Sakuma N, Usami SI. Gene expression profiles of the cochlea and vestibular endorgans: localization and function of genes causing deafness. Ann Otol Rhinol Laryngol 2015; 124 Suppl 1:6S-48S. [PMID: 25814645 DOI: 10.1177/0003489415575549] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES We sought to elucidate the gene expression profiles of the causative genes as well as the localization of the encoded proteins involved in hereditary hearing loss. METHODS Relevant articles (as of September 2014) were searched in PubMed databases, and the gene symbols of the genes reported to be associated with deafness were located on the Hereditary Hearing Loss Homepage using localization, expression, and distribution as keywords. RESULTS Our review of the literature allowed us to systematize the gene expression profiles for genetic deafness in the inner ear, clarifying the unique functions and specific expression patterns of these genes in the cochlea and vestibular endorgans. CONCLUSIONS The coordinated actions of various encoded molecules are essential for the normal development and maintenance of auditory and vestibular function.
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Affiliation(s)
- Shin-Ya Nishio
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Mitsuru Hattori
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hideaki Moteki
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Keita Tsukada
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Maiko Miyagawa
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takehiko Naito
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hidekane Yoshimura
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yoh-Ichiro Iwasa
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kentaro Mori
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yutaka Shima
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Naoko Sakuma
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Otorhinolaryngology and Head and Neck Surgery, Yokohama City University School of Medicine, Yokohama, Japan
| | - Shin-Ichi Usami
- Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Japan
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66
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Downsloping high-frequency hearing loss due to inner ear tricellular tight junction disruption by a novel ILDR1 mutation in the Ig-like domain. PLoS One 2015; 10:e0116931. [PMID: 25668204 PMCID: PMC4323246 DOI: 10.1371/journal.pone.0116931] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 12/16/2014] [Indexed: 11/19/2022] Open
Abstract
The immunoglobulin (Ig)-like domain containing receptor 1 (ILDR1) gene encodes angulin-2/ILDR1, a recently discovered tight junction protein, which forms tricellular tight junction (tTJ) structures with tricellulin and lipolysis-stimulated lipoprotein receptor (LSR) at tricellular contacts (TCs) in the inner ear. Previously reported recessive mutations within ILDR1 have been shown to cause severe to profound nonsyndromic sensorineural hearing loss (SNHL), DFNB42. Whole-exome sequencing of a Korean multiplex family segregating partial deafness identified a novel homozygous ILDR1 variant (p.P69H) within the Ig-like domain. To address the pathogenicity of p.P69H, the angulin-2/ILDR1 p.P69H variant protein, along with the previously reported pathogenic ILDR1 mutations, was expressed in angulin-1/LSR knockdown epithelial cells. Interestingly, partial mislocalization of the p.P69H variant protein and tricellulin at TCs was observed, in contrast to a severe mislocalization and complete failure of tricellulin recruitment of the other reported ILDR1 mutations. Additionally, three-dimensional protein modeling revealed that angulin-2/ILDR1 contributed to tTJ by forming a homo-trimer structure through its Ig-like domain, and the p.P69H variant was predicted to disturb homo-trimer formation. In this study, we propose a possible role of angulin-2/ILDR1 in tTJ formation in the inner ear and a wider audiologic phenotypic spectrum of DFNB42 caused by mutations within ILDR1.
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67
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Vaz-Drago R, Pinheiro MT, Martins S, Enguita FJ, Carmo-Fonseca M, Custódio N. Transcription-coupled RNA surveillance in human genetic diseases caused by splice site mutations. Hum Mol Genet 2015; 24:2784-95. [PMID: 25652404 DOI: 10.1093/hmg/ddv039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/31/2015] [Indexed: 12/15/2022] Open
Abstract
Current estimates indicate that approximately one-third of all disease-causing mutations are expected to disrupt splicing. Abnormal splicing often leads to disruption of the reading frame with introduction of a premature termination codon (PTC) that targets the mRNA for degradation in the cytoplasm by nonsense mediated decay (NMD). In addition to NMD there are RNA surveillance mechanisms that act in the nucleus while transcripts are still associated with the chromatin template. However, the significance of nuclear RNA quality control in the context of human genetic diseases is unknown. Here we used patient-derived lymphoblastoid cell lines as disease models to address how biogenesis of mRNAs is affected by splice site mutations. We observed that most of the mutations analyzed introduce PTCs and trigger mRNA degradation in the cytoplasm. However, for some mutant transcripts, RNA levels associated with chromatin were found down-regulated. Quantification of nascent transcripts further revealed that a subset of genes containing splicing mutations (SM) have reduced transcriptional activity. Following treatment with the translation inhibitor cycloheximide the cytoplasmic levels of mutant RNAs increased, while the levels of chromatin-associated transcripts remained unaltered. These results suggest that transcription-coupled surveillance mechanisms operate independently from NMD to reduce cellular levels of abnormal RNAs caused by SM.
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Affiliation(s)
- Rita Vaz-Drago
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Marco T Pinheiro
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Sandra Martins
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Francisco J Enguita
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Noélia Custódio
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
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68
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Krug SM, Schulzke JD, Fromm M. Tight junction, selective permeability, and related diseases. Semin Cell Dev Biol 2014; 36:166-76. [DOI: 10.1016/j.semcdb.2014.09.002] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 08/29/2014] [Accepted: 09/04/2014] [Indexed: 02/09/2023]
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69
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Spontaneous regeneration of cochlear supporting cells after neonatal ablation ensures hearing in the adult mouse. Proc Natl Acad Sci U S A 2014; 111:16919-24. [PMID: 25385613 DOI: 10.1073/pnas.1408064111] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Supporting cells in the cochlea play critical roles in the development, maintenance, and function of sensory hair cells and auditory neurons. Although the loss of hair cells or auditory neurons results in sensorineural hearing loss, the consequence of supporting cell loss on auditory function is largely unknown. In this study, we specifically ablated inner border cells (IBCs) and inner phalangeal cells (IPhCs), the two types of supporting cells surrounding inner hair cells (IHCs) in mice in vivo. We demonstrate that the organ of Corti has the intrinsic capacity to replenish IBCs/IPhCs effectively during early postnatal development. Repopulation depends on the presence of hair cells and cells within the greater epithelial ridge and is independent of cell proliferation. This plastic response in the neonatal cochlea preserves neuronal survival, afferent innervation, and hearing sensitivity in adult mice. In contrast, the capacity for IBC/IPhC regeneration is lost in the mature organ of Corti, and consequently IHC survival and hearing sensitivity are impaired significantly, demonstrating that there is a critical period for the regeneration of cochlear supporting cells. Our findings indicate that the quiescent neonatal organ of Corti can replenish specific supporting cells completely after loss in vivo to guarantee mature hearing function.
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70
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Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014; 244:239-53. [PMID: 25255879 DOI: 10.1002/dvdy.24195] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
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Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
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71
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Lundberg YW, Xu Y, Thiessen KD, Kramer KL. Mechanisms of otoconia and otolith development. Dev Dyn 2014. [PMID: 25255879 DOI: 10.1002/dvdy.24195(2014)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Otoconia are bio-crystals that couple mechanic forces to the sensory hair cells in the utricle and saccule, a process essential for us to sense linear acceleration and gravity for the purpose of maintaining bodily balance. In fish, structurally similar bio-crystals called otoliths mediate both balance and hearing. Otoconia abnormalities are common and can cause vertigo and imbalance in humans. However, the molecular etiology of these illnesses is unknown, as investigators have only begun to identify genes important for otoconia formation in recent years. RESULTS To date, in-depth studies of selected mouse otoconial proteins have been performed, and about 75 zebrafish genes have been identified to be important for otolith development. CONCLUSIONS This review will summarize recent findings as well as compare otoconia and otolith development. It will provide an updated brief review of otoconial proteins along with an overview of the cells and cellular processes involved. While continued efforts are needed to thoroughly understand the molecular mechanisms underlying otoconia and otolith development, it is clear that the process involves a series of temporally and spatially specific events that are tightly coordinated by numerous proteins. Such knowledge will serve as the foundation to uncover the molecular causes of human otoconia-related disorders.
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Affiliation(s)
- Yunxia Wang Lundberg
- Vestibular Genetics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska
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72
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Morozko EL, Nishio A, Ingham NJ, Chandra R, Fitzgerald T, Martelletti E, Borck G, Wilson E, Riordan GP, Wangemann P, Forge A, Steel KP, Liddle RA, Friedman TB, Belyantseva IA. ILDR1 null mice, a model of human deafness DFNB42, show structural aberrations of tricellular tight junctions and degeneration of auditory hair cells. Hum Mol Genet 2014; 24:609-24. [PMID: 25217574 PMCID: PMC4291242 DOI: 10.1093/hmg/ddu474] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the mammalian inner ear, bicellular and tricellular tight junctions (tTJs) seal the paracellular space between epithelial cells. Tricellulin and immunoglobulin-like (Ig-like) domain containing receptor 1 (ILDR1, also referred to as angulin-2) localize to tTJs of the sensory and non-sensory epithelia in the organ of Corti and vestibular end organs. Recessive mutations of TRIC (DFNB49) encoding tricellulin and ILDR1 (DFNB42) cause human nonsyndromic deafness. However, the pathophysiology of DFNB42 deafness remains unknown. ILDR1 was recently reported to be a lipoprotein receptor mediating the secretion of the fat-stimulated cholecystokinin (CCK) hormone in the small intestine, while ILDR1 in EpH4 mouse mammary epithelial cells in vitro was shown to recruit tricellulin to tTJs. Here we show that two different mouse Ildr1 mutant alleles have early-onset severe deafness associated with a rapid degeneration of cochlear hair cells (HCs) but have a normal endocochlear potential. ILDR1 is not required for recruitment of tricellulin to tTJs in the cochlea in vivo; however, tricellulin becomes mislocalized in the inner ear sensory epithelia of ILDR1 null mice after the first postnatal week. As revealed by freeze-fracture electron microscopy, ILDR1 contributes to the ultrastructure of inner ear tTJs. Taken together, our data provide insight into the pathophysiology of human DFNB42 deafness and demonstrate that ILDR1 is crucial for normal hearing by maintaining the structural and functional integrity of tTJs, which are critical for the survival of auditory neurosensory HCs.
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Affiliation(s)
- Eva L Morozko
- National Institute on Deafness and Other Communication Disorders, Section on Human Genetics
| | - Ayako Nishio
- National Institute on Deafness and Other Communication Disorders, Molecular Biology and Genetics Section
| | - Neil J Ingham
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, UK
| | - Rashmi Chandra
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Tracy Fitzgerald
- National Institute on Deafness and Other Communication Disorders, Mouse Auditory Testing Core Facility, National Institutes of Health, Bethesda, MD 20892-3729, USA
| | - Elisa Martelletti
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, UK
| | - Guntram Borck
- Institute of Human Genetics, University of Ulm, Ulm 89081, Germany
| | - Elizabeth Wilson
- National Institute on Deafness and Other Communication Disorders, Section on Human Genetics
| | - Gavin P Riordan
- National Institute on Deafness and Other Communication Disorders, Section on Human Genetics
| | - Philine Wangemann
- Anatomy and Physiology Department, Kansas State University, Manhattan, KS 66506-5802, USA and
| | - Andrew Forge
- Centre for Auditory Research, University College London, London WC1X 8EE, UK
| | - Karen P Steel
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, UK
| | - Rodger A Liddle
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | - Thomas B Friedman
- National Institute on Deafness and Other Communication Disorders, Section on Human Genetics
| | - Inna A Belyantseva
- National Institute on Deafness and Other Communication Disorders, Section on Human Genetics
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73
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Oda Y, Otani T, Ikenouchi J, Furuse M. Tricellulin regulates junctional tension of epithelial cells at tricellular contacts through Cdc42. J Cell Sci 2014; 127:4201-12. [PMID: 25097232 DOI: 10.1242/jcs.150607] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
When the surface view of each epithelial cell is compared with a polygon, its sides correspond to cell-cell junctions, whereas its vertices correspond to tricellular contacts, whose roles in epithelial cell morphogenesis have not been well studied. Here, we show that tricellulin (also known as MARVELD2), which is localized at tricellular contacts, regulates F-actin organization through Cdc42. Tricellulin-knockdown epithelial cells exhibit irregular polygonal shapes with curved cell borders and impaired organization of F-actin fibers around tricellular contacts during cell-cell junction formation. The N-terminal cytoplasmic domain of tricellulin binds to the Cdc42 guanine-nucleotide-exchange factor (GEF) Tuba (also known as DNMBP and ARHGEF36), and activates Cdc42. A tricellulin mutant that lacks the ability to bind Tuba cannot rescue the curved cell border phenotype of tricellulin-knockdown cells. These findings indicate that tricellular contacts play crucial roles in regulating the actomyosin-mediated apical junctional complex tension through the tricellulin-Tuba-Cdc42 system.
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Affiliation(s)
- Yukako Oda
- Division of Cell Biology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Tetsuhisa Otani
- Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Chuo-ku, Kobe 650-0047, Japan
| | - Junichi Ikenouchi
- Department of Biology, Faculty of Sciences, Kyushu University, Kyushu, 812-8581, Japan PRESTO, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Mikio Furuse
- Division of Cell Biology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki 444-8787, Japan Department of Physiological Sciences, The Graduate School for Advanced Studies, Okazaki 444-8585, Japan
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74
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Kitajiri SI, Katsuno T, Sasaki H, Ito J, Furuse M, Tsukita S. Deafness in occludin-deficient mice with dislocation of tricellulin and progressive apoptosis of the hair cells. Biol Open 2014; 3:759-66. [PMID: 25063198 PMCID: PMC4133728 DOI: 10.1242/bio.20147799] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Occludin is the first identified protein in the tight junction (TJ), but its function has remained for the most part obscure. TJs have been demonstrated to play important roles in the inner ear function, and occludin is expressed in all the epithelial TJs in the inner ear. Thus, we examined the inner ears of occludin-deficient (Occ−/−) mice. Although inner ears initially developed normally in Occ−/− mice, apoptosis occurs in hair cells in the organ of Corti around day 12 after birth, and deafness develops. Since hair cell degeneration was not observed in cochlear explant cultures of Occ−/− mice, environmental changes were considered to be the trigger of cell death. As for the vestibular system, both the morphologies and functions are normal in Occ−/− mice. These phenotypes of Occ−/− mice are very similar with those of claudin-14 or claudin-9 deficient mice, leading us to speculate on the existence of imbalance induced by TJ abnormalities, such as localized ionic components. Moreover, the occludin deficiency led to dislocalization of tricellulin, a gene responsible for human deafness DFNB49. The deafness in Occ−/− mice may be due to this dislocalization of tricellulin.
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Affiliation(s)
- Shin-Ichiro Kitajiri
- Department of Otolaryngology, Head and Neck Surgery, Kyoto University Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tatsuya Katsuno
- Department of Otolaryngology, Head and Neck Surgery, Kyoto University Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Hiroyuki Sasaki
- Department of Physical Therapy, Faculty of Community Health Care, Teikyo Heisei University, Uruido Minami, Ichihara, Chiba 290-0193, Japan
| | - Juichi Ito
- Department of Otolaryngology, Head and Neck Surgery, Kyoto University Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
| | - Mikio Furuse
- Department of Cell Biology, Division of Cell Biology, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan Division of Cerebral Structure, National Institute for Physiological Sciences, Okazaki, 444-8787, Japan
| | - Shoichiro Tsukita
- Department of Cell Biology, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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75
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Sang Q, Zhang J, Feng R, Wang X, Li Q, Zhao X, Xing Q, Chen W, Du J, Sun S, Chai R, Liu D, Jin L, He L, Li H, Wang L. Ildr1b is essential for semicircular canal development, migration of the posterior lateral line primordium and hearing ability in zebrafish: implications for a role in the recessive hearing impairment DFNB42. Hum Mol Genet 2014; 23:6201-11. [PMID: 24990150 DOI: 10.1093/hmg/ddu340] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Immunoglobulin-like domain containing receptor 1 (ILDR1) is a poorly characterized gene that was first identified in lymphoma cells. Recently, ILDR1 has been found to be responsible for autosomal recessive hearing impairment DFNB42. Patients with ILDR1 mutations cause bilateral non-progressive moderate-to-profound sensorineural hearing impairment. However, the etiology and mechanism of ILDR1-related hearing loss remains to be elucidated. In order to uncover the pathology of DFNB42 deafness, we used the morpholino injection technique to establish an ildr1b-morphant zebrafish model. Ildr1b-morphant zebrafish displayed defective hearing and imbalanced swimming, and developmental delays were seen in the semicircular canals of the inner ear. The gene expression profile and real-time PCR revealed down-regulation of atp1b2b (encoding Na(+)/K(+) transporting, beta 2b polypeptide) in ildr1b-morphant zebrafish. We found that injection of atp1b2b mRNA into ildr1b-knockdown zebrafish could rescue the phenotype of developmental delay of the semicircular canals. Moreover, ildr1b-morphant zebrafish had reduced numbers of lateral line neuromasts due to the disruption of lateral line primordium migration. In situ hybridization showed the involvement of attenuated FGF signaling and the chemokine receptor 4b (cxcr4b) and chemokine receptor 7b (cxcr7b) in posterior lateral line primordium of ildr1b-morphant zebrafish. We concluded that Ildr1b is crucial for the development of the inner ear and the lateral line system. This study provides the first evidence for the mechanism of Ildr1b on hearing in vivo and sheds light on the pathology of DFNB42.
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Affiliation(s)
- Qing Sang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai 200032, PR China, Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China
| | - Junyu Zhang
- Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China
| | - Ruizhi Feng
- Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China
| | - Xu Wang
- The Key Laboratory of Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Qiaoli Li
- Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China
| | - Xinzhi Zhao
- Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China
| | - Qinghe Xing
- Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China
| | - Weiyu Chen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China
| | - Jiulin Du
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China
| | - Shan Sun
- Department of Otolaryngology, Eye and ENT Hospital, Fudan University, 83 Fenyang Road, Shanghai 200031, PR China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China and
| | - Dong Liu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong 226001, China
| | - Li Jin
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai 200032, PR China
| | - Lin He
- Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China, Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200030, PR China
| | - Huawei Li
- Department of Otolaryngology, Eye and ENT Hospital, Fudan University, 83 Fenyang Road, Shanghai 200031, PR China,
| | - Lei Wang
- State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai 200032, PR China, Institutes of Biomedical Sciences, Fudan University, No 138 Yixueyuan Road, Shanghai 200032, PR China,
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76
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Lu RY, Yang WX, Hu YJ. The role of epithelial tight junctions involved in pathogen infections. Mol Biol Rep 2014; 41:6591-610. [PMID: 24965148 DOI: 10.1007/s11033-014-3543-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/20/2014] [Indexed: 12/12/2022]
Abstract
Tight junctions (TJs) are sealing complexes between adjacent epithelial cells, functioning by controlling paracellular passage and maintaining cell polarity. These functions of TJs are primarily based on structural integrity as well as dynamic regulatory balance, indicating plasticity of TJ in response to external stimuli. An indispensable role of TJs involved in pathogen infection has been widely demonstrated since disruption of TJs leads to a distinct increase in paracellular permeability and polarity defects which facilitate viral or bacterial entry and spread. In addition to pathological changes in TJ integrity, TJ proteins such as occludin and claudins can either function as receptors for pathogen entry or interact with viral/bacterial effector molecules as an essential step for characterizing an infective stage. This suggests a more complicated role for TJ itself and especially specific TJ components. Thus, this review surveys the role of the epithelial TJs involved in various pathogen infections, and extends TJ targeted therapeutic and pharmacological application prospects.
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Affiliation(s)
- Ru-Yi Lu
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, China
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77
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Nakatsu D, Kano F, Taguchi Y, Sugawara T, Nishizono T, Nishikawa K, Oda Y, Furuse M, Murata M. JNK1/2-dependent phosphorylation of angulin-1/LSR is required for the exclusive localization of angulin-1/LSR and tricellulin at tricellular contacts in EpH4 epithelial sheet. Genes Cells 2014; 19:565-81. [PMID: 24889144 DOI: 10.1111/gtc.12158] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 03/27/2014] [Indexed: 01/16/2023]
Abstract
Tricellular tight junctions (tTJs) are specialized structural variants of tight junctions within tricellular contacts of an epithelial sheet and comprise several transmembrane proteins including lipolysis-stimulated lipoprotein receptor (angulin-1/LSR) and tricellulin. To elucidate the mechanism of its formation, we carried out stepwise screening of kinase inhibitors followed by RNAi screening to identify kinases that regulate intracellular localization of angulin-1/LSR to the tTJs using a fluorescence image-based screen. We found that the activity of JNK1 and JNK2, but not JNK3, was required for the exclusive localization of angulin-1/LSR at the tTJs. Based on a bioinformatics approach, we estimated the potential phosphorylation site of angulin-1/LSR by JNK1 to be serine 288 and experimentally confirmed that JNK1 directly phosphorylates angulin-1/LSR at this site. We found that JNK2 was also involved in the phosphorylation of angulin-1/LSR. Furthermore, GFP-tagged angulin-1/LSR(S288A), in which serine 288 was substituted by alanine, was observed to be dispersed to bicellular junctions, indicating that phosphorylation of Ser288 is crucial for the exclusive localization of angulin-1/LSR and tricellulin at tTJs. Our fluorescence image-based screening for kinases inhibitor or siRNAs combined with the phosphorylation site prediction could become a versatile and useful tool to elucidate the mechanisms underlying the maintenance of tTJs regulated by kinase networks.
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Affiliation(s)
- Daiki Nakatsu
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan
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78
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Abstract
Within an epithelial cellular sheet, the paracellular pathway can be divided into two routes: one between two adjacent cells and one at tricellular contacts, where the vertices of three cells meet. For epithelial barrier function, tight junctions restrict solute permeability through the paracellular pathway between two cells, while tricellular contacts contain specialized structures of tight junctions, named tricellular tight junctions (tTJs). Two types of membrane proteins, tricellulin and angulin family proteins (angulin-1/LSR, angulin-2/ILDR1 and angulin-3/ILDR2) have been identified as molecular components of tTJs. Angulins recruit triellulin to tTJs and these tTJ-associated proteins are required for normal tTJ formation as well as strong epithelial barrier function. Furthermore, mutations in tricellulin and angulin-2/ILDR1 genes cause autosomal recessive familial deafness, DFNB49 and DFNB42, respectively. Further analyses of the angulin-tricellulin system should lead to better understanding of the molecular mechanism and regulation of tTJs.
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Affiliation(s)
- Mikio Furuse
- Division of Cell Biology, Kobe University Graduate School of Medicine
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79
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Furuse M, Izumi Y, Oda Y, Higashi T, Iwamoto N. Molecular organization of tricellular tight junctions. Tissue Barriers 2014; 2:e28960. [PMID: 25097825 PMCID: PMC4117683 DOI: 10.4161/tisb.28960] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/19/2014] [Accepted: 04/21/2014] [Indexed: 01/22/2023] Open
Abstract
When the apicolateral border of epithelial cells is compared with a polygon, its sides correspond to the apical junctional complex, where cell adhesion molecules assemble from the plasma membranes of two adjacent cells. On the other hand, its vertices correspond to tricellular contacts, where the corners of three cells meet. Vertebrate tricellular contacts have specialized structures of tight junctions, termed tricellular tight junctions (tTJs). tTJs were identified by electron microscopic observations more than 40 years ago, but have been largely forgotten in epithelial cell biology since then. The identification of tricellulin and angulin family proteins as tTJ-associated membrane proteins has enabled us to study tTJs in terms of not only the paracellular barrier function but also unknown characteristics of epithelial cell corners via molecular biological approaches.
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Affiliation(s)
- Mikio Furuse
- Division of Cell Biology; Department of Physiology and Cell Biology; Kobe University Graduate School of Medicine; Kobe, Japan ; Division of Cerebral Structure; National Institute for Physiological Sciences; Okazaki, Aichi Japan
| | - Yasushi Izumi
- Division of Cell Biology; Department of Physiology and Cell Biology; Kobe University Graduate School of Medicine; Kobe, Japan
| | - Yukako Oda
- Division of Cell Biology; Department of Physiology and Cell Biology; Kobe University Graduate School of Medicine; Kobe, Japan
| | - Tomohito Higashi
- Division of Cell Biology; Department of Physiology and Cell Biology; Kobe University Graduate School of Medicine; Kobe, Japan
| | - Noriko Iwamoto
- Division of Cell Biology; Department of Physiology and Cell Biology; Kobe University Graduate School of Medicine; Kobe, Japan
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80
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Higashi T, Lenz DR, Furuse M, Avraham KB. A "Tric" to tighten cell-cell junctions in the cochlea for hearing. J Clin Invest 2013; 123:3712-5. [PMID: 23979155 DOI: 10.1172/jci69651] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Tricellulin is a tricellular tight junction-associated membrane protein that controls movement of solutes at these specialized cell intersections. Mutations in the gene encoding tricellulin, TRIC, lead to nonsyndromic deafness. In this issue of the JCI, Nayak et al. created a gene-targeted knockin mouse in order to mimic the pathology of a human TRIC mutation. Deafness appears to be caused either by an increase in the K+ ion concentration around the basolateral surfaces of the outer hair cells or, alternatively, by an increase in small molecules such as ATP around the hair bundle, leading to cellular dysfunction and degeneration. Furthermore, the mice have features suggestive of syndromic hearing loss, which may have implications for care and treatment of patients harboring TRIC mutations.
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Affiliation(s)
- Tomohito Higashi
- Division of Cell Biology, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
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