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Li J, Choi BY, Eltawil Y, Ismail Mohamad N, Park Y, Matthews IR, Han JH, Kim BJ, Sherr EH, Chan DK. TMTC4 is a hair cell-specific human deafness gene. JCI Insight 2023; 8:e172665. [PMID: 37943620 PMCID: PMC10807715 DOI: 10.1172/jci.insight.172665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023] Open
Abstract
Transmembrane and tetratricopeptide repeat 4 (Tmtc4) is a deafness gene in mice. Tmtc4-KO mice have rapidly progressive postnatal hearing loss due to overactivation of the unfolded protein response (UPR); however, the cellular basis and human relevance of Tmtc4-associated hearing loss in the cochlea was not heretofore appreciated. We created a hair cell-specific conditional KO mouse that phenocopies the constitutive KO with postnatal onset deafness, demonstrating that Tmtc4 is a hair cell-specific deafness gene. Furthermore, we identified a human family in which Tmtc4 variants segregate with adult-onset progressive hearing loss. Lymphoblastoid cells derived from multiple affected and unaffected family members, as well as human embryonic kidney cells engineered to harbor each of the variants, demonstrated that the human Tmtc4 variants confer hypersensitivity of the UPR toward apoptosis. These findings provide evidence that TMTC4 is a deafness gene in humans and further implicate the UPR in progressive hearing loss.
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Affiliation(s)
- Jiang Li
- Department of Neurology and
- Department of Pediatrics, Institute of Human Genetics, Weill Institute for Neurosciences, UCSF, San Francisco, California, USA
| | - Byung Yoon Choi
- Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seoul, South Korea
| | - Yasmin Eltawil
- Department of Otolaryngology-Head and Neck Surgery, San Francisco, California, USA
| | - Noura Ismail Mohamad
- Department of Otolaryngology-Head and Neck Surgery, San Francisco, California, USA
| | - Yesai Park
- Department of Otolaryngology-Head and Neck Surgery, San Francisco, California, USA
| | - Ian R. Matthews
- Department of Otolaryngology-Head and Neck Surgery, San Francisco, California, USA
| | - Jin Hee Han
- Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seoul, South Korea
- Department of Otorhinolaryngology, Chungnam National University College of Medicine, Chungnam National University Sejong Hospital, Sejong City, South Korea
| | - Bong Jik Kim
- Department of Otorhinolaryngology, Chungnam National University College of Medicine, Chungnam National University Sejong Hospital, Sejong City, South Korea
| | - Elliott H. Sherr
- Department of Neurology and
- Department of Pediatrics, Institute of Human Genetics, Weill Institute for Neurosciences, UCSF, San Francisco, California, USA
| | - Dylan K. Chan
- Department of Otolaryngology-Head and Neck Surgery, San Francisco, California, USA
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Linnert J, Knapp B, Güler BE, Boldt K, Ueffing M, Wolfrum U. Usher syndrome proteins ADGRV1 (USH2C) and CIB2 (USH1J) interact and share a common interactome containing TRiC/CCT-BBS chaperonins. Front Cell Dev Biol 2023; 11:1199069. [PMID: 37427378 PMCID: PMC10323441 DOI: 10.3389/fcell.2023.1199069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
The human Usher syndrome (USH) is the most common form of a sensory hereditary ciliopathy characterized by progressive vision and hearing loss. Mutations in the genes ADGRV1 and CIB2 have been associated with two distinct sub-types of USH, namely, USH2C and USH1J. The proteins encoded by the two genes belong to very distinct protein families: the adhesion G protein-coupled receptor ADGRV1 also known as the very large G protein-coupled receptor 1 (VLGR1) and the Ca2+- and integrin-binding protein 2 (CIB2), respectively. In the absence of tangible knowledge of the molecular function of ADGRV1 and CIB2, pathomechanisms underlying USH2C and USH1J are still unknown. Here, we aimed to enlighten the cellular functions of CIB2 and ADGRV1 by the identification of interacting proteins, a knowledge that is commonly indicative of cellular functions. Applying affinity proteomics by tandem affinity purification in combination with mass spectrometry, we identified novel potential binding partners of the CIB2 protein and compared these with the data set we previously obtained for ADGRV1. Surprisingly, the interactomes of both USH proteins showed a high degree of overlap indicating their integration in common networks, cellular pathways and functional modules which we confirmed by GO term analysis. Validation of protein interactions revealed that ADGRV1 and CIB2 mutually interact. In addition, we showed that the USH proteins also interact with the TRiC/CCT chaperonin complex and the Bardet Biedl syndrome (BBS) chaperonin-like proteins. Immunohistochemistry on retinal sections demonstrated the co-localization of the interacting partners at the photoreceptor cilia, supporting the role of USH proteins ADGRV1 and CIB2 in primary cilia function. The interconnection of protein networks involved in the pathogenesis of both syndromic retinal dystrophies BBS and USH suggest shared pathomechanisms for both syndromes on the molecular level.
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Affiliation(s)
- Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Barbara Knapp
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Baran E. Güler
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Karsten Boldt
- Institute for Ophthalmic Research, Eberhard Karls University of Tuebingen, Tubingen, Germany
| | - Marius Ueffing
- Institute for Ophthalmic Research, Eberhard Karls University of Tuebingen, Tubingen, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University Mainz, Mainz, Germany
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Xing Y, Peng K, Yi Q, Yu D, Shi H, Yang G, Yin S. TMEM30A is essential for hair cell polarity maintenance in postnatal mouse cochlea. Cell Mol Biol Lett 2023; 28:23. [PMID: 36959542 PMCID: PMC10035192 DOI: 10.1186/s11658-023-00437-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/08/2023] [Indexed: 03/25/2023] Open
Abstract
BACKGROUND Phosphatidylserine is translocated to the inner leaflet of the phospholipid bilayer membrane by the flippase function of type IV P-tape ATPase (P4-ATPase), which is critical to maintain cellular stability and homeostasis. Transmembrane protein 30A (TMEM30A) is the β-subunit of P4-ATPase. Loss of P4-ATPase function causes sensorineural hearing loss and visual dysfunction in human. However, the function of TMEM30A in the auditory system is unclear. METHODS P4-ATPase subtype expression in the cochlea was detected by immunofluorescence staining and quantitative real-time polymerase chain reaction (qRT-PCR) at different developmental stages. Hair cell specific TMEM30A knockout mice and wild-type littermates were used for the following functional and morphological analysis. Auditory function was evaluated by auditory brainstem response. We investigated hair cell and stereocilia morphological changes by immunofluorescence staining. Scanning electron microscopy was applied to observe the stereocilia ultrastructure. Differentially expressed transcriptomes were analyzed based on RNA-sequencing data from knockout and wild-type mouse cochleae. Differentially expressed genes were verified by qRT-PCR. RESULTS TMEM30A and subtypes of P4-ATPase are expressed in the mouse cochlea in a temporal-dependent pattern. Deletion of TMEM30A in hair cells impaired hearing onset due to progressive hair cell loss. The disrupted kinocilia placement and irregular distribution of spectrin-α in cuticular plate indicated the hair cell planar polarity disruption in TMEM30A deletion hair cells. Hair cell degeneration begins at P7 and finishes around P14. Transcriptional analysis indicates that the focal adhesion pathway and stereocilium tip-related genes changed dramatically. Without the TMEM30A chaperone, excessive ATP8A2 accumulated in the cytoplasm, leading to overwhelming endoplasmic reticulum stress, which eventually contributed to hair cell death. CONCLUSIONS Deletion of TMEM30A led to disrupted planar polarity and stereocilia bundles, and finally led to hair cell loss and auditory dysfunction. TMEM30A is essential for hair cell polarity maintenance and membrane homeostasis. Our study highlights a pivotal role of TMEM30A in the postnatal development of hair cells and reveals the possible mechanisms underlying P4-ATPase-related genetic hearing loss.
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Affiliation(s)
- Yazhi Xing
- Department of Otolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1301 Research Bldg, 600 Yishan Rd, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, 600 Yishan Rd, Shanghai, 200233, China
| | - Kun Peng
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610054, Sichuan, China
| | - Qian Yi
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, 610054, Sichuan, China
| | - Dongzhen Yu
- Department of Otolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1301 Research Bldg, 600 Yishan Rd, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, 600 Yishan Rd, Shanghai, 200233, China
| | - Haibo Shi
- Department of Otolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1301 Research Bldg, 600 Yishan Rd, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, 600 Yishan Rd, Shanghai, 200233, China
| | - Guang Yang
- Department of Otolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1301 Research Bldg, 600 Yishan Rd, Shanghai, China.
- Otolaryngology Institute of Shanghai Jiao Tong University, 600 Yishan Rd, Shanghai, 200233, China.
| | - Shankai Yin
- Department of Otolaryngology Head & Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 1301 Research Bldg, 600 Yishan Rd, Shanghai, China
- Otolaryngology Institute of Shanghai Jiao Tong University, 600 Yishan Rd, Shanghai, 200233, China
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Gao G, Guo S, Zhang Q, Zhang H, Zhang C, Peng G. Kiaa1024L/Minar2 is essential for hearing by regulating cholesterol distribution in hair bundles. eLife 2022; 11:e80865. [PMID: 36317962 PMCID: PMC9714970 DOI: 10.7554/elife.80865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/31/2022] [Indexed: 12/05/2022] Open
Abstract
Unbiased genetic screens implicated a number of uncharacterized genes in hearing loss, suggesting some biological processes required for auditory function remain unexplored. Loss of Kiaa1024L/Minar2, a previously understudied gene, caused deafness in mice, but how it functioned in the hearing was unclear. Here, we show that disruption of kiaa1024L/minar2 causes hearing loss in the zebrafish. Defects in mechanotransduction, longer and thinner hair bundles, and enlarged apical lysosomes in hair cells are observed in the kiaa1024L/minar2 mutant. In cultured cells, Kiaa1024L/Minar2 is mainly localized to lysosomes, and its overexpression recruits cholesterol and increases cholesterol labeling. Strikingly, cholesterol is highly enriched in the hair bundle membrane, and loss of kiaa1024L/minar2 reduces cholesterol localization to the hair bundles. Lowering cholesterol levels aggravates, while increasing cholesterol levels rescues the hair cell defects in the kiaa1024L/minar2 mutant. Therefore, cholesterol plays an essential role in hair bundles, and Kiaa1024L/Minar2 regulates cholesterol distribution and homeostasis to ensure normal hearing.
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Affiliation(s)
- Ge Gao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
| | - Shuyu Guo
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
| | - Quan Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
| | - Hefei Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
| | - Cuizhen Zhang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
| | - Gang Peng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan UniversityShanghaiChina
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5
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Ikäheimo K, Herranen A, Iivanainen V, Lankinen T, Aarnisalo AA, Sivonen V, Patel KA, Demir K, Saarma M, Lindahl M, Pirvola U. MANF supports the inner hair cell synapse and the outer hair cell stereocilia bundle in the cochlea. Life Sci Alliance 2021; 5:5/2/e202101068. [PMID: 34815294 PMCID: PMC8616558 DOI: 10.26508/lsa.202101068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 11/29/2022] Open
Abstract
The authors show in the mouse how the auditory hair cell structural maintenance is perturbed by the inactivation of Manf and the concomitant ER stress, causing early-onset, progressive hearing loss. Failure in the structural maintenance of the hair cell stereocilia bundle and ribbon synapse causes hearing loss. Here, we have studied how ER stress elicits hair cell pathology, using mouse models with inactivation of Manf (mesencephalic astrocyte-derived neurotrophic factor), encoding an ER-homeostasis-promoting protein. From hearing onset, Manf deficiency caused disarray of the outer hair cell stereocilia bundle and reduced cochlear sound amplification capability throughout the tonotopic axis. In high-frequency outer hair cells, the pathology ended in molecular changes in the stereocilia taper region and in strong stereocilia fusion. In high-frequency inner hair cells, Manf deficiency degraded ribbon synapses. The altered phenotype strongly depended on the mouse genetic background. Altogether, the failure in the ER homeostasis maintenance induced early-onset stereociliopathy and synaptopathy and accelerated the effect of genetic causes driving age-related hearing loss. Correspondingly, MANF mutation in a human patient induced severe sensorineural hearing loss from a young age onward. Thus, we present MANF as a novel protein and ER stress as a mechanism that regulate auditory hair cell maintenance in both mice and humans.
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Affiliation(s)
- Kuu Ikäheimo
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Anni Herranen
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Vilma Iivanainen
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Tuuli Lankinen
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Antti A Aarnisalo
- Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Ville Sivonen
- Department of Otorhinolaryngology-Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Kashyap A Patel
- Institute of Biomedical and Clinical Science, College of Medicine and Health, University of Exeter, Exeter, UK
| | - Korcan Demir
- Department of Paediatric Endocrinology, Dokuz Eylul University, Izmir, Turkey
| | - Mart Saarma
- Institute of Biotechnology, HILIFE Unit, University of Helsinki, Helsinki, Finland
| | - Maria Lindahl
- Institute of Biotechnology, HILIFE Unit, University of Helsinki, Helsinki, Finland
| | - Ulla Pirvola
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
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6
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Marom R, Burrage LC, Venditti R, Clément A, Blanco-Sánchez B, Jain M, Scott DA, Rosenfeld JA, Sutton VR, Shinawi M, Mirzaa G, DeVile C, Roberts R, Calder AD, Allgrove J, Grafe I, Lanza DG, Li X, Joeng KS, Lee YC, Song IW, Sliepka JM, Batkovskyte D, Washington M, Dawson BC, Jin Z, Jiang MM, Chen S, Chen Y, Tran AA, Emrick LT, Murdock DR, Hanchard NA, Zapata GE, Mehta NR, Weis MA, Scott AA, Tremp BA, Phillips JB, Wegner J, Taylor-Miller T, Gibbs RA, Muzny DM, Jhangiani SN, Hicks J, Stottmann RW, Dickinson ME, Seavitt JR, Heaney JD, Eyre DR, Westerfield M, De Matteis MA, Lee B. COPB2 loss of function causes a coatopathy with osteoporosis and developmental delay. Am J Hum Genet 2021; 108:1710-1724. [PMID: 34450031 PMCID: PMC8456174 DOI: 10.1016/j.ajhg.2021.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/04/2021] [Indexed: 02/08/2023] Open
Abstract
Coatomer complexes function in the sorting and trafficking of proteins between subcellular organelles. Pathogenic variants in coatomer subunits or associated factors have been reported in multi-systemic disorders, i.e., coatopathies, that can affect the skeletal and central nervous systems. We have identified loss-of-function variants in COPB2, a component of the coatomer complex I (COPI), in individuals presenting with osteoporosis, fractures, and developmental delay of variable severity. Electron microscopy of COPB2-deficient subjects' fibroblasts showed dilated endoplasmic reticulum (ER) with granular material, prominent rough ER, and vacuoles, consistent with an intracellular trafficking defect. We studied the effect of COPB2 deficiency on collagen trafficking because of the critical role of collagen secretion in bone biology. COPB2 siRNA-treated fibroblasts showed delayed collagen secretion with retention of type I collagen in the ER and Golgi and altered distribution of Golgi markers. copb2-null zebrafish embryos showed retention of type II collagen, disorganization of the ER and Golgi, and early larval lethality. Copb2+/- mice exhibited low bone mass, and consistent with the findings in human cells and zebrafish, studies in Copb2+/- mouse fibroblasts suggest ER stress and a Golgi defect. Interestingly, ascorbic acid treatment partially rescued the zebrafish developmental phenotype and the cellular phenotype in Copb2+/- mouse fibroblasts. This work identifies a form of coatopathy due to COPB2 haploinsufficiency, explores a potential therapeutic approach for this disorder, and highlights the role of the COPI complex as a regulator of skeletal homeostasis.
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Affiliation(s)
- Ronit Marom
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Lindsay C Burrage
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | | | - Aurélie Clément
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Mahim Jain
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Daryl A Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Marwan Shinawi
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Ghayda Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, and Department of Pediatrics, University of Washington, and Brotman Baty Institute for Precision Medicine, Seattle, WA 98105, USA
| | - Catherine DeVile
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Rowenna Roberts
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Alistair D Calder
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Jeremy Allgrove
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Ingo Grafe
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Denise G Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiaohui Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kyu Sang Joeng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yi-Chien Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - I-Wen Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joseph M Sliepka
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dominyka Batkovskyte
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Megan Washington
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brian C Dawson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zixue Jin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ming-Ming Jiang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shan Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yuqing Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alyssa A Tran
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lisa T Emrick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Section of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - David R Murdock
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Neil A Hanchard
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA; Laboratory for Translational Genomics, ARS/USDA Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Gladys E Zapata
- Laboratory for Translational Genomics, ARS/USDA Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nitesh R Mehta
- Laboratory for Translational Genomics, ARS/USDA Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mary Ann Weis
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 98195, USA
| | - Abbey A Scott
- Division of Genetic Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Brenna A Tremp
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Jeremy Wegner
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - John Hicks
- Texas Children's Hospital, Houston, TX 77030, USA; Department of Pathology, Texas Children's Hospital, and Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Rolf W Stottmann
- Division of Human Genetics, and Division of Developmental Biology, and Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Mary E Dickinson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA
| | - John R Seavitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jason D Heaney
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - David R Eyre
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 98195, USA
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Maria Antonietta De Matteis
- Telethon Institute of Genetics and Medicine, Naples 80078, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Napoli Federico II, Naples 80078, Italy
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA.
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7
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Fuster-García C, García-Bohórquez B, Rodríguez-Muñoz A, Aller E, Jaijo T, Millán JM, García-García G. Usher Syndrome: Genetics of a Human Ciliopathy. Int J Mol Sci 2021; 22:6723. [PMID: 34201633 PMCID: PMC8268283 DOI: 10.3390/ijms22136723] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/21/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive syndromic ciliopathy characterized by sensorineural hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. There are three clinical types depending on the severity and age of onset of the symptoms; in addition, ten genes are reported to be causative of USH, and six more related to the disease. These genes encode proteins of a diverse nature, which interact and form a dynamic protein network called the "Usher interactome". In the organ of Corti, the USH proteins are essential for the correct development and maintenance of the structure and cohesion of the stereocilia. In the retina, the USH protein network is principally located in the periciliary region of the photoreceptors, and plays an important role in the maintenance of the periciliary structure and the trafficking of molecules between the inner and the outer segments of photoreceptors. Even though some genes are clearly involved in the syndrome, others are controversial. Moreover, expression of some USH genes has been detected in other tissues, which could explain their involvement in additional mild comorbidities. In this paper, we review the genetics of Usher syndrome and the spectrum of mutations in USH genes. The aim is to identify possible mutation associations with the disease and provide an updated genotype-phenotype correlation.
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Affiliation(s)
- Carla Fuster-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Belén García-Bohórquez
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
- Genetics Unit, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe (IIS La Fe), 46026 Valencia, Spain; (C.F.-G.); (B.G.-B.); (A.R.-M.); (E.A.); (T.J.); (G.G.-G.)
- Unidad Mixta de Enfermedades Raras IIS La Fe-Centro de Investigación Príncipe Felipe, 46026 Valencia, Spain
- Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, 46026 Valencia, Spain
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8
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Sheets L, Holmgren M, Kindt KS. How Zebrafish Can Drive the Future of Genetic-based Hearing and Balance Research. J Assoc Res Otolaryngol 2021; 22:215-235. [PMID: 33909162 PMCID: PMC8110678 DOI: 10.1007/s10162-021-00798-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/23/2021] [Indexed: 02/06/2023] Open
Abstract
Over the last several decades, studies in humans and animal models have successfully identified numerous molecules required for hearing and balance. Many of these studies relied on unbiased forward genetic screens based on behavior or morphology to identify these molecules. Alongside forward genetic screens, reverse genetics has further driven the exploration of candidate molecules. This review provides an overview of the genetic studies that have established zebrafish as a genetic model for hearing and balance research. Further, we discuss how the unique advantages of zebrafish can be leveraged in future genetic studies. We explore strategies to design novel forward genetic screens based on morphological alterations using transgenic lines or behavioral changes following mechanical or acoustic damage. We also outline how recent advances in CRISPR-Cas9 can be applied to perform reverse genetic screens to validate large sequencing datasets. Overall, this review describes how future genetic studies in zebrafish can continue to advance our understanding of inherited and acquired hearing and balance disorders.
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Affiliation(s)
- Lavinia Sheets
- Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Melanie Holmgren
- Department of Otolaryngology-Head & Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | - Katie S Kindt
- Section On Sensory Cell Development and Function, National Institutes On Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, USA.
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9
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Alassaf M, Halloran MC. Pregnancy-associated plasma protein-aa regulates endoplasmic reticulum-mitochondria associations. eLife 2021; 10:59687. [PMID: 33759764 PMCID: PMC8024009 DOI: 10.7554/elife.59687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 03/23/2021] [Indexed: 11/13/2022] Open
Abstract
Endoplasmic reticulum (ER) and mitochondria form close physical associations to facilitate calcium transfer, thereby regulating mitochondrial function. Neurons with high metabolic demands, such as sensory hair cells, are especially dependent on precisely regulated ER-mitochondria associations. We previously showed that the secreted metalloprotease pregnancy-associated plasma protein-aa (Pappaa) regulates mitochondrial function in zebrafish lateral line hair cells (Alassaf et al., 2019). Here, we show that pappaa mutant hair cells exhibit excessive and abnormally close ER-mitochondria associations, suggesting increased ER-mitochondria calcium transfer. pappaa mutant hair cells are more vulnerable to pharmacological induction of ER-calcium transfer. Additionally, pappaa mutant hair cells display ER stress and dysfunctional downstream processes of the ER-mitochondria axis including altered mitochondrial morphology and reduced autophagy. We further show that Pappaa influences ER-calcium transfer and autophagy via its ability to stimulate insulin-like growth factor-1 bioavailability. Together our results identify Pappaa as a novel regulator of the ER-mitochondria axis.
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Affiliation(s)
- Mroj Alassaf
- Department of Integrative Biology, University of Wisconsin, Madison, United States.,Department of Neuroscience, University of Wisconsin, Madison, United States.,Neuroscience Training Program, University of Wisconsin, Madison, United States
| | - Mary C Halloran
- Department of Integrative Biology, University of Wisconsin, Madison, United States.,Department of Neuroscience, University of Wisconsin, Madison, United States.,Neuroscience Training Program, University of Wisconsin, Madison, United States
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10
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Spectrum of MYO7A Mutations in an Indigenous South African Population Further Elucidates the Nonsyndromic Autosomal Recessive Phenotype of DFNB2 to Include Both Homozygous and Compound Heterozygous Mutations. Genes (Basel) 2021; 12:genes12020274. [PMID: 33671976 PMCID: PMC7919343 DOI: 10.3390/genes12020274] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 11/17/2022] Open
Abstract
MYO7A gene encodes unconventional myosin VIIA, which, when mutated, causes a phenotypic spectrum ranging from recessive hearing loss DFNB2 to deaf-blindness, Usher Type 1B (USH1B). MYO7A mutations are reported in nine DFNB2 families to date, none from sub-Saharan Africa.In DNA, from a cohort of 94 individuals representing 92 families from the Limpopo province of South Africa, eight MYO7A variations were detected among 10 individuals. Family studies identified homozygous and compound heterozygous mutations in 17 individuals out of 32 available family members. Four mutations were novel, p.Gly329Asp, p.Arg373His, p.Tyr1780Ser, and p.Pro2126Leufs*5. Two variations, p.Ser617Pro and p.Thr381Met, previously listed as of uncertain significance (ClinVar), were confirmed to be pathogenic. The identified mutations are predicted to interfere with the conformational properties of myosin VIIA through interruption or abrogation of multiple interactions between the mutant and neighbouring residues. Specifically, p.Pro2126Leufs*5, is predicted to abolish the critical site for the interactions between the tail and the motor domain essential for the autoregulation, leaving a non-functional, unregulated protein that causes hearing loss. We have identified MYO7A as a possible key deafness gene among indigenous sub-Saharan Africans. The spectrum of MYO7A mutations in this South African population points to DFNB2 as a specific entity that may occur in a homozygous or in a compound heterozygous state.
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11
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Whatley M, Francis A, Ng ZY, Khoh XE, Atlas MD, Dilley RJ, Wong EYM. Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy. Front Genet 2020; 11:565216. [PMID: 33193648 PMCID: PMC7642844 DOI: 10.3389/fgene.2020.565216] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped. The proteins encoded by these genes form complexes that play critical roles in the development and maintenance of cellular structures within the inner ear and retina, which have minimal capacity for repair or regeneration. In the cochlea, stereocilia are located on the apical surface of inner ear hair cells (HC) and are responsible for transducing mechanical stimuli from sound pressure waves into chemical signals. These signals are then detected by the auditory nerve fibers, transmitted to the brain and interpreted as sound. Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction. This review summarizes the current knowledge on Usher syndrome with a particular emphasis on mutations in USH genes, USH protein structures, and functional analyses in animal models. Currently, there is no cure for USH. However, the genetic therapies that are rapidly developing will benefit from this compilation of detailed genetic information to identify the most effective strategies for restoring functional USH proteins.
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Affiliation(s)
- Meg Whatley
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Abbie Francis
- Ear Science Institute Australia, Nedlands, WA, Australia
- Emergency Medicine, The University of Western Australia, Nedlands, WA, Australia
| | - Zi Ying Ng
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Xin Ee Khoh
- Ear Science Institute Australia, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
| | - Rodney J. Dilley
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Perth, WA, Australia
| | - Elaine Y. M. Wong
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
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12
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Xu A, Shang W, Wang Y, Sun X, Zhou B, Xie Y, Xu X, Liu T, Han F. ALA protects against ERS-mediated apoptosis in a cochlear cell model with low citrate synthase expression. Arch Biochem Biophys 2020; 688:108402. [PMID: 32418909 DOI: 10.1016/j.abb.2020.108402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/06/2020] [Accepted: 04/29/2020] [Indexed: 01/04/2023]
Abstract
A/J mouse is a model of age-related hearing loss (AHL). Mutation in the citrate synthase (Cs) gene of the mouse plays an important role in the hearing loss and degeneration of cochlear cells. To investigate the pathogenesis of cochlear cell damage in A/J mice resulted from Cs mutation, we downregulated the expression level of CS in HEI-OC1, a cell line of mouse cochlea, by shRNA. The results showed that low CS expression led to low ability of cell proliferation. Further study revealed an increase level of reactive oxygen species (ROS), activation of ATF6 mediated endoplasmic reticulum stress (ERS) and high expression levels of caspase12 and Bax in the cells. Moreover, the AEBSF, an ATF6 inhibitor, could reduce the expression levels of caspase-12 and Bax by inhibiting the hydrolysis of ATF6 in the cells. Finally, antioxidant alpha-lipoic acid (ALA) reduced the ROS levels and the apoptotic signals in the cell model with low CS expression. We therefore conclude that the ERS mediated apoptosis, which is triggered by ROS, may be involved in the cell degeneration in the cochleae of A/J mice.
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Affiliation(s)
- Ang Xu
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Otolaryngology, Yantai Affiliated Hospital of Binzhou Medical University, 717 Jinbu Road of Muping District, Yantai, 264100, Shandong, PR China
| | - Wenjing Shang
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Biochemistry and Molecular Biology, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China
| | - Yan Wang
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Biochemistry and Molecular Biology, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China
| | - Xiumei Sun
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Otolaryngology, Yantai Affiliated Hospital of Binzhou Medical University, 717 Jinbu Road of Muping District, Yantai, 264100, Shandong, PR China
| | - Bingxin Zhou
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Biochemistry and Molecular Biology, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China
| | - Yi Xie
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Biochemistry and Molecular Biology, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China
| | - Xiaowen Xu
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Otolaryngology, Yantai Affiliated Hospital of Binzhou Medical University, 717 Jinbu Road of Muping District, Yantai, 264100, Shandong, PR China
| | - Tingyan Liu
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Otolaryngology, Yantai Affiliated Hospital of Binzhou Medical University, 717 Jinbu Road of Muping District, Yantai, 264100, Shandong, PR China.
| | - Fengchan Han
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China; Department of Biochemistry and Molecular Biology, Binzhou Medical University, 346 Guanhai Road, Yantai, 264003, Shandong, PR China.
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13
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Blanco-Sánchez B, Clément A, Stednitz SJ, Kyle J, Peirce JL, McFadden M, Wegner J, Phillips JB, Macnamara E, Huang Y, Adams DR, Toro C, Gahl WA, Malicdan MCV, Tifft CJ, Zink EM, Bloodsworth KJ, Stratton KG, Koeller DM, Metz TO, Washbourne P, Westerfield M. yippee like 3 (ypel3) is a novel gene required for myelinating and perineurial glia development. PLoS Genet 2020; 16:e1008841. [PMID: 32544203 PMCID: PMC7319359 DOI: 10.1371/journal.pgen.1008841] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 06/26/2020] [Accepted: 05/08/2020] [Indexed: 12/30/2022] Open
Abstract
Hypomyelination, a neurological condition characterized by decreased production of myelin sheets by glial cells, often has no known etiology. Elucidating the genetic causes of hypomyelination provides a better understanding of myelination, as well as means to diagnose, council, and treat patients. Here, we present evidence that YIPPEE LIKE 3 (YPEL3), a gene whose developmental role was previously unknown, is required for central and peripheral glial cell development. We identified a child with a constellation of clinical features including cerebral hypomyelination, abnormal peripheral nerve conduction, hypotonia, areflexia, and hypertrophic peripheral nerves. Exome and genome sequencing revealed a de novo mutation that creates a frameshift in the open reading frame of YPEL3, leading to an early stop codon. We used zebrafish as a model system to validate that YPEL3 mutations are causative of neuropathy. We found that ypel3 is expressed in the zebrafish central and peripheral nervous system. Using CRISPR/Cas9 technology, we created zebrafish mutants carrying a genomic lesion similar to that of the patient. Our analysis revealed that Ypel3 is required for development of oligodendrocyte precursor cells, timely exit of the perineurial glial precursors from the central nervous system (CNS), formation of the perineurium, and Schwann cell maturation. Consistent with these observations, zebrafish ypel3 mutants have metabolomic signatures characteristic of oligodendrocyte and Schwann cell differentiation defects, show decreased levels of Myelin basic protein in the central and peripheral nervous system, and develop defasciculated peripheral nerves. Locomotion defects were observed in adult zebrafish ypel3 mutants. These studies demonstrate that Ypel3 is a novel gene required for perineurial cell development and glial myelination.
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Affiliation(s)
| | - Aurélie Clément
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Sara J. Stednitz
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Jennifer Kyle
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Judy L. Peirce
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Marcie McFadden
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Jeremy Wegner
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Jennifer B. Phillips
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Ellen Macnamara
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yan Huang
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David R. Adams
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Camilo Toro
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - William A. Gahl
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
- Section of Human Biochemical Genetics, Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - May Christine V. Malicdan
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Cynthia J. Tifft
- National Institutes of Health Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland, United States of America
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Erika M. Zink
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Kent J. Bloodsworth
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Kelly G. Stratton
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | | | - David M. Koeller
- Molecular and Medical Genetics, School of Medicine, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Thomas O. Metz
- Pacific Northwest National Laboratory, Richland, Washington, United States of America
| | - Philip Washbourne
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
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14
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Deficiency of the ER-stress-regulator MANF triggers progressive outer hair cell death and hearing loss. Cell Death Dis 2020; 11:100. [PMID: 32029702 PMCID: PMC7005028 DOI: 10.1038/s41419-020-2286-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 11/28/2022]
Abstract
The non-conventional neurotrophic factor mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER)-resident protein that promotes ER homeostasis. MANF has a cytoprotective function, shown in the central nervous system neurons and pancreatic beta cells. Here, we report that MANF is expressed in the hair cells and neurons and in selected non-sensory cells of the cochlea and that Manf inactivation triggers upregulation of the ER chaperones in these cells. However, Manf inactivation resulted in the death of only outer hair cells (OHCs), the cells responsible for sound amplification in the cochlea. All OHCs were formed in Manf-inactivated mice, but progressive OHC death started soon after the onset of hearing function. The robust OHC loss was accompanied by strongly elevated hearing thresholds. Conditional Manf inactivation demonstrated that MANF has a local function in the cochlea. Immunostainings revealed the upregulation of CHOP, the pro-apoptotic component of the unfolded protein response (UPR), in Manf-inactivated OHCs, linking the UPR to the loss of these cells. The phenotype of Manf-inactivated OHCs was distinctly dependent on the mouse strain, such that the strains characterized by early-onset age-related hearing loss (C57BL/6J and CD-1) were affected. These results suggest that Manf deficiency becomes detrimental when accompanied by gene mutations that predispose to hearing loss, by intensifying ER dyshomeostasis. Together, MANF is the first growth factor shown to antagonize ER stress-mediated OHC death. MANF might serve as a therapeutic candidate for protection against hearing loss induced by the ER-machinery-targeting stressors.
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15
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Erickson T, Pacentine IV, Venuto A, Clemens R, Nicolson T. The lhfpl5 Ohnologs lhfpl5a and lhfpl5b Are Required for Mechanotransduction in Distinct Populations of Sensory Hair Cells in Zebrafish. Front Mol Neurosci 2020; 12:320. [PMID: 32009898 PMCID: PMC6974483 DOI: 10.3389/fnmol.2019.00320] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/16/2019] [Indexed: 01/20/2023] Open
Abstract
Hair cells sense and transmit auditory, vestibular, and hydrodynamic information by converting mechanical stimuli into electrical signals. This process of mechano-electrical transduction (MET) requires a mechanically gated channel localized in the apical stereocilia of hair cells. In mice, lipoma HMGIC fusion partner-like 5 (LHFPL5) acts as an auxiliary subunit of the MET channel whose primary role is to correctly localize PCDH15 and TMC1 to the mechanotransduction complex. Zebrafish have two lhfpl5 genes (lhfpl5a and lhfpl5b), but their individual contributions to MET channel assembly and function have not been analyzed. Here we show that the zebrafish lhfpl5 genes are expressed in discrete populations of hair cells: lhfpl5a expression is restricted to auditory and vestibular hair cells in the inner ear, while lhfpl5b expression is specific to hair cells of the lateral line organ. Consequently, lhfpl5a mutants exhibit defects in auditory and vestibular function, while disruption of lhfpl5b affects hair cells only in the lateral line neuromasts. In contrast to previous reports in mice, localization of Tmc1 does not depend upon Lhfpl5 function in either the inner ear or lateral line organ. In both lhfpl5a and lhfpl5b mutants, GFP-tagged Tmc1 and Tmc2b proteins still localize to the stereocilia of hair cells. Using a stably integrated GFP-Lhfpl5a transgene, we show that the tip link cadherins Pcdh15a and Cdh23, along with the Myo7aa motor protein, are required for correct Lhfpl5a localization at the tips of stereocilia. Our work corroborates the evolutionarily conserved co-dependence between Lhfpl5 and Pcdh15, but also reveals novel requirements for Cdh23 and Myo7aa to correctly localize Lhfpl5a. In addition, our data suggest that targeting of Tmc1 and Tmc2b proteins to stereocilia in zebrafish hair cells occurs independently of Lhfpl5 proteins.
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Affiliation(s)
- Timothy Erickson
- Department of Biology, East Carolina University, Greenville, NC, United States.,Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - Itallia V Pacentine
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - Alexandra Venuto
- Department of Biology, East Carolina University, Greenville, NC, United States
| | - Rachel Clemens
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - Teresa Nicolson
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR, United States
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16
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Abstract
The inner ear, which mediates the senses of hearing and balance, derives from a simple ectodermal vesicle in the vertebrate embryo. In the zebrafish, the otic placode and vesicle express a whole suite of genes required for ciliogenesis and ciliary motility. Every cell of the otic epithelium is ciliated at early stages; at least three different ciliary subtypes can be distinguished on the basis of length, motility, genetic requirements and function. In the early otic vesicle, most cilia are short and immotile. Long, immotile kinocilia on the first sensory hair cells tether the otoliths, biomineralized aggregates of calcium carbonate and protein. Small numbers of motile cilia at the poles of the otic vesicle contribute to the accuracy of otolith tethering, but neither the presence of cilia nor ciliary motility is absolutely required for this process. Instead, otolith tethering is dependent on the presence of hair cells and the function of the glycoprotein Otogelin. Otic cilia or ciliary proteins also mediate sensitivity to ototoxins and coordinate responses to extracellular signals. Other studies are beginning to unravel the role of ciliary proteins in cellular compartments other than the kinocilium, where they are important for the integrity and survival of the sensory hair cell. This article is part of the Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.
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Affiliation(s)
- Tanya T Whitfield
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
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17
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Caspase-8 Regulates Endoplasmic Reticulum Stress-Induced Necroptosis Independent of the Apoptosis Pathway in Auditory Cells. Int J Mol Sci 2019; 20:ijms20235896. [PMID: 31771290 PMCID: PMC6928907 DOI: 10.3390/ijms20235896] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/15/2019] [Accepted: 11/21/2019] [Indexed: 12/20/2022] Open
Abstract
The aim of this study is to elucidate the detailed mechanism of endoplasmic reticulum (ER) stress-induced auditory cell death based on the function of the initiator caspases and molecular complex of necroptosis. Here, we demonstrated that ER stress initiates not only caspase-9-dependent intrinsic apoptosis along with caspase-3, but also receptor-interacting serine/threonine kinase (RIPK)1-dependent necroptosis in auditory cells. We observed the ultrastructural characteristics of both apoptosis and necroptosis in tunicamycin-treated cells under transmission electron microscopy (TEM). We demonstrated that ER stress-induced necroptosis was dependent on the induction of RIPK1, negatively regulated by caspase-8 in auditory cells. Our data suggested that ER stress-induced intrinsic apoptosis depends on the induction of caspase-9 along with caspase-3 in auditory cells. The results of this study reveal that necroptosis could exist for the alternative backup cell death route of apoptosis in auditory cells under ER stress. Interestingly, our data results in a surge in the recognition that therapies aimed at the inner ear protection effect by caspase inhibitors like zVAD-fmk might arrest apoptosis but can also have the unanticipated effect of promoting necroptosis. Thus, RIPK1-dependent necroptosis would be a new therapeutic target for the treatment of sensorineural hearing loss due to ER stress.
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18
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Megdiche S, Mastrangelo S, Ben Hamouda M, Lenstra JA, Ciani E. A Combined Multi-Cohort Approach Reveals Novel and Known Genome-Wide Selection Signatures for Wool Traits in Merino and Merino-Derived Sheep Breeds. Front Genet 2019; 10:1025. [PMID: 31708969 PMCID: PMC6824410 DOI: 10.3389/fgene.2019.01025] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 09/24/2019] [Indexed: 12/24/2022] Open
Abstract
Merino sheep represents a valuable genetic resource worldwide. In this study, we investigated selection signatures in Merino (and Merino-derived) sheep breeds using genome-wide SNP data and two different approaches: a classical FST-outlier method and an approach based on the analysis of local ancestry in admixed populations. In order to capture the most reliable signals, we adopted a combined, multi-cohort approach. In particular, scenarios involving four Merino breeds (Spanish Merino, Australian Merino, Chinese Merino, and Sopravissana) were tested via the local ancestry approach, while nine pair-wise breed comparisons contrasting the above breeds, as well as the Gentile di Puglia breed, with non-Merino breeds from the same geographic area were tested via the FST-outlier method. Signals observed using both methods were compared with genome-wide patterns of distribution of runs of homozygosity (ROH) islands. Novel and known selection signatures were detected. The most reliable signals were observed on OAR 3 (MSRB3 and LEMD3), OAR10 (FRY and RXFP2), OAR 13 (RALY), OAR17 (FAM101A), and OAR18 (NFKBIA, SEC23A, and PAX9). All the above overlapped with known QTLs for wool traits, and evidences from the literature of their involvement in skin/hair/wool biology, as well as gene network analysis, further corroborated these results. The signal on OAR10 also contains well known evidence for association with horn morphology and polledness. More elusive biological evidences of association with the Merino phenotype were observed for a number of other genes, notably LOC101120019 and TMEM132B (OAR17), LOC105609948 (OAR3), LOC101110773 (OAR10), and EIF2S2 (OAR17). Taken together, the above results further contribute to decipher the genetic basis underlying the Merino phenotype.
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Affiliation(s)
- Sami Megdiche
- Départment des Ressources Animales, Agroalimentaire et Développement Rural, Institut Supérieur Agronomique de Chott-Mariem, Université de Sousse, Sousse, Tunisia
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, University of Bari “Aldo Moro,”Bari, Italy
| | - Salvatore Mastrangelo
- Dipartimento di Scienze Agrarie, Alimentari e Forestali, University of Palermo, Palermo, Italy
| | | | | | - Elena Ciani
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica, University of Bari “Aldo Moro,”Bari, Italy
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19
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Sorusch N, Yildirim A, Knapp B, Janson J, Fleck W, Scharf C, Wolfrum U. SANS (USH1G) Molecularly Links the Human Usher Syndrome Protein Network to the Intraflagellar Transport Module by Direct Binding to IFT-B Proteins. Front Cell Dev Biol 2019; 7:216. [PMID: 31637240 PMCID: PMC6787559 DOI: 10.3389/fcell.2019.00216] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 09/18/2019] [Indexed: 01/19/2023] Open
Abstract
The human Usher syndrome (USH) is a retinal ciliopathy, characterized by profound congenital deafness, variable vestibular dysfunction and pre-pubertal onset of retinitis pigmentosa. In the effected sensory cells, USH protein networks are assumed to function in ciliary transport processes. The USH1G protein SANS is a scaffold of the ciliary/periciliary USH protein network of photoreceptor cells. Moreover, SANS is associated with microtubules, the transport routes for protein delivery toward the cilium. To enlighten the role of SANS in ciliary transport processes, we aimed to identify transport related proteins associated with SANS. The intraflagellar transport (IFT) system is a conserved mechanism for bi-directional transport toward and through primary cilia. Thus, we tested the direct binding of SANS to IFT molecules, namely IFT20, IFT57, and IFT74 in 1:1 yeast-two-hybrid assay. The identified SANS-IFT interactions were validated in vitro via independent complementary interaction assays and in cells by applying membrane targeting assays. Quantitative immunofluorescence microscopy revealed the co-localization of SANS with IFT20, IFT52, and IFT57 particularly at ciliary base of wild type mouse photoreceptor cells. Analysis of photoreceptor cells of SANS knock out mice revealed the decrease of IFTs in the ciliary compartment indicating a role of SANS in the proper positioning of IFT-B molecules in primary cilia. Our study demonstrated direct binding of IFT complex B proteins IFT52 and IFT57 to the N-terminal ankyrin repeats and the central domain of SANS. Our data also indicate that pathologic mutations in the N-terminus of SANS lead to the loos of SANS binding to IFT-B molecules. Our findings provide direct evidence for a molecular link between the ciliary USH protein network and the IFT transport module in primary cilia.
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Affiliation(s)
| | | | | | | | | | | | - Uwe Wolfrum
- Molecular Cell Biology, Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
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20
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Stawicki TM, Linbo T, Hernandez L, Parkinson L, Bellefeuille D, Rubel EW, Raible DW. The role of retrograde intraflagellar transport genes in aminoglycoside-induced hair cell death. Biol Open 2019; 8:bio.038745. [PMID: 30578252 PMCID: PMC6361216 DOI: 10.1242/bio.038745] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Sensory hair cells are susceptible to numerous insults, including certain therapeutic medications like aminoglycoside antibiotics, and hearing and balance disorders are often a dose-limiting side effect of these medications. We show that mutations in multiple genes in both the retrograde intraflagellar transport (IFT) motor and adaptor complexes lead to resistance to aminoglycoside-induced hair cell death. These mutations also lead to defects in the entry of both aminoglycosides and the vital dye FM1-43 into hair cells, both processes that depend on hair cell mechanotransduction activity. However, the trafficking of proteins important for mechanotransduction activity is not altered by these mutations. Our data suggest that both retrograde IFT motor and adaptor complex genes are playing a role in aminoglycoside toxicity through affecting aminoglycoside uptake into hair cells. Summary: Here we show that both retrograde intraflagellar transport motor proteins and IFT-A adaptor molecules play a role in aminoglycoside-induced hair cell death, seemingly through regulating aminoglycoside uptake.
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Affiliation(s)
- Tamara M Stawicki
- Program in Neuroscience, Lafayette College, Easton, PA 18042, USA .,Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Tor Linbo
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Liana Hernandez
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Lauren Parkinson
- Program in Neuroscience, Lafayette College, Easton, PA 18042, USA
| | | | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA
| | - David W Raible
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA.,Virginia Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA 98195, USA
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21
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Pickett SB, Raible DW. Water Waves to Sound Waves: Using Zebrafish to Explore Hair Cell Biology. J Assoc Res Otolaryngol 2019; 20:1-19. [PMID: 30635804 DOI: 10.1007/s10162-018-00711-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/19/2018] [Indexed: 01/09/2023] Open
Abstract
Although perhaps best known for their use in developmental studies, over the last couple of decades, zebrafish have become increasingly popular model organisms for investigating auditory system function and disease. Like mammals, zebrafish possess inner ear mechanosensory hair cells required for hearing, as well as superficial hair cells of the lateral line sensory system, which mediate detection of directional water flow. Complementing mammalian studies, zebrafish have been used to gain significant insights into many facets of hair cell biology, including mechanotransduction and synaptic physiology as well as mechanisms of both hereditary and acquired hair cell dysfunction. Here, we provide an overview of this literature, highlighting some of the particular advantages of using zebrafish to investigate hearing and hearing loss.
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Affiliation(s)
- Sarah B Pickett
- Department of Biological Structure, University of Washington, Health Sciences Building H-501, 1959 NE Pacific Street, Box 357420, Seattle, WA, 98195-7420, USA
- Graduate Program in Neuroscience, University of Washington, 1959 NE Pacific Street, Box 357270, Seattle, WA, 98195-7270, USA
| | - David W Raible
- Department of Biological Structure, University of Washington, Health Sciences Building H-501, 1959 NE Pacific Street, Box 357420, Seattle, WA, 98195-7420, USA.
- Graduate Program in Neuroscience, University of Washington, 1959 NE Pacific Street, Box 357270, Seattle, WA, 98195-7270, USA.
- Virginia Merrill Bloedel Hearing Research Center, University of Washington, 1701 NE Columbia Rd, Box 357923, Seattle, WA, 98195-7923, USA.
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22
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Blanco-Sánchez B, Clément A, Fierro J, Stednitz S, Phillips JB, Wegner J, Panlilio JM, Peirce JL, Washbourne P, Westerfield M. Grxcr1 Promotes Hair Bundle Development by Destabilizing the Physical Interaction between Harmonin and Sans Usher Syndrome Proteins. Cell Rep 2018; 25:1281-1291.e4. [PMID: 30380418 PMCID: PMC6284068 DOI: 10.1016/j.celrep.2018.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/11/2018] [Accepted: 09/28/2018] [Indexed: 01/02/2023] Open
Abstract
Morphogenesis and mechanoelectrical transduction of the hair cell mechanoreceptor depend on the correct assembly of Usher syndrome (USH) proteins into highly organized macromolecular complexes. Defects in these proteins lead to deafness and vestibular areflexia in USH patients. Mutations in a non-USH protein, glutaredoxin domain-containing cysteine-rich 1 (GRXCR1), cause non-syndromic sensorineural deafness. To understand the deglutathionylating enzyme function of GRXCR1 in deafness, we generated two grxcr1 zebrafish mutant alleles. We found that hair bundles are thinner in homozygous grxcr1 mutants, similar to the USH1 mutants ush1c (Harmonin) and ush1ga (Sans). In vitro assays showed that glutathionylation promotes the interaction between Ush1c and Ush1ga and that Grxcr1 regulates mechanoreceptor development by preventing physical interaction between these proteins without affecting the assembly of another USH1 protein complex, the Ush1c-Cadherin23-Myosin7aa tripartite complex. By elucidating the molecular mechanism through which Grxcr1 functions, we also identify a mechanism that dynamically regulates the formation of Usher protein complexes.
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Affiliation(s)
| | - Aurélie Clément
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Javier Fierro
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Sarah Stednitz
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Jeremy Wegner
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Judy L Peirce
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Philip Washbourne
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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23
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Li J, Akil O, Rouse SL, McLaughlin CW, Matthews IR, Lustig LR, Chan DK, Sherr EH. Deletion of Tmtc4 activates the unfolded protein response and causes postnatal hearing loss. J Clin Invest 2018; 128:5150-5162. [PMID: 30188326 DOI: 10.1172/jci97498] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 08/30/2018] [Indexed: 12/16/2022] Open
Abstract
Hearing loss is a significant public health concern, affecting over 250 million people worldwide. Both genetic and environmental etiologies are linked to hearing loss, but in many cases the underlying cellular pathophysiology is not well understood, highlighting the importance of further discovery. We found that inactivation of the gene Tmtc4 (transmembrane and tetratricopeptide repeat 4), which was broadly expressed in the mouse cochlea, caused acquired hearing loss in mice. Our data showed Tmtc4 enriched in the endoplasmic reticulum, and that it functioned by regulating Ca2+ dynamics and the unfolded protein response (UPR). Given this genetic linkage of the UPR to hearing loss, we demonstrated a direct link between the more common noise-induced hearing loss (NIHL) and the UPR. These experiments suggested a novel approach to treatment. We demonstrated that the small-molecule UPR and stress response modulator ISRIB (integrated stress response inhibitor), which activates eIF2B, prevented NIHL in a mouse model. Moreover, in an inverse genetic complementation approach, we demonstrated that mice with homozygous inactivation of both Tmtc4 and Chop had less hearing loss than knockout of Tmtc4 alone. This study implicated a novel mechanism for hearing impairment, highlighting a potential treatment approach for a broad range of human hearing loss disorders.
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Affiliation(s)
| | - Omar Akil
- Department of Otolaryngology - Head and Neck Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Stephanie L Rouse
- Department of Otolaryngology - Head and Neck Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Conor W McLaughlin
- Department of Otolaryngology - Head and Neck Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Ian R Matthews
- Department of Otolaryngology - Head and Neck Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Lawrence R Lustig
- Department of Otolaryngology - Head and Neck Surgery, College of Physicians and Surgeons, Columbia University and New York Presbyterian Hospital, New York, New York, USA
| | - Dylan K Chan
- Department of Otolaryngology - Head and Neck Surgery, University of California San Francisco (UCSF), San Francisco, California, USA
| | - Elliott H Sherr
- Department of Neurology and.,Department of Pediatrics, Institute of Human Genetics, Weill Institute for Neurosciences, UCSF, San Francisco, California, USA
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24
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Ferreira CR, Xia ZJ, Clément A, Parry DA, Davids M, Taylan F, Sharma P, Turgeon CT, Blanco-Sánchez B, Ng BG, Logan CV, Wolfe LA, Solomon BD, Cho MT, Douglas G, Carvalho DR, Bratke H, Haug MG, Phillips JB, Wegner J, Tiemeyer M, Aoki K, Nordgren A, Hammarsjö A, Duker AL, Rohena L, Hove HB, Ek J, Adams D, Tifft CJ, Onyekweli T, Weixel T, Macnamara E, Radtke K, Powis Z, Earl D, Gabriel M, Russi AHS, Brick L, Kozenko M, Tham E, Raymond KM, Phillips JA, Tiller GE, Wilson WG, Hamid R, Malicdan MC, Nishimura G, Grigelioniene G, Jackson A, Westerfield M, Bober MB, Gahl WA, Freeze HH, Gahl WA, Freeze HH. A Recurrent De Novo Heterozygous COG4 Substitution Leads to Saul-Wilson Syndrome, Disrupted Vesicular Trafficking, and Altered Proteoglycan Glycosylation. Am J Hum Genet 2018; 103:553-567. [PMID: 30290151 DOI: 10.1016/j.ajhg.2018.09.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/31/2018] [Indexed: 12/18/2022] Open
Abstract
The conserved oligomeric Golgi (COG) complex is involved in intracellular vesicular transport, and is composed of eight subunits distributed in two lobes, lobe A (COG1-4) and lobe B (COG5-8). We describe fourteen individuals with Saul-Wilson syndrome, a rare form of primordial dwarfism with characteristic facial and radiographic features. All affected subjects harbored heterozygous de novo variants in COG4, giving rise to the same recurrent amino acid substitution (p.Gly516Arg). Affected individuals' fibroblasts, whose COG4 mRNA and protein were not decreased, exhibited delayed anterograde vesicular trafficking from the ER to the Golgi and accelerated retrograde vesicular recycling from the Golgi to the ER. This altered steady-state equilibrium led to a decrease in Golgi volume, as well as morphologic abnormalities with collapse of the Golgi stacks. Despite these abnormalities of the Golgi apparatus, protein glycosylation in sera and fibroblasts from affected subjects was not notably altered, but decorin, a proteoglycan secreted into the extracellular matrix, showed altered Golgi-dependent glycosylation. In summary, we define a specific heterozygous COG4 substitution as the molecular basis of Saul-Wilson syndrome, a rare skeletal dysplasia distinct from biallelic COG4-CDG.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - William A Gahl
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hudson H Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
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25
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Clément A, Blanco-Sánchez B, Peirce JL, Westerfield M. Cog4 is required for protrusion and extension of the epithelium in the developing semicircular canals. Mech Dev 2018; 155:1-7. [PMID: 30287385 DOI: 10.1016/j.mod.2018.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/06/2018] [Accepted: 09/22/2018] [Indexed: 11/17/2022]
Abstract
The semicircular canals in the inner ear sense angular acceleration. In zebrafish, the semicircular canals develop from epithelial projections that grow toward each other and fuse to form pillars. The growth of the epithelial projections is driven by the production and secretion of extracellular matrix components by the epithelium. The conserved oligomeric Golgi 4 protein, Cog4, functions in retrograde vesicle transport within the Golgi and mutations can lead to sensory neural hearing loss. In zebrafish cog4 mutants, the inner ear is smaller and the number of hair cells is reduced. Here, we show that formation of the pillars is delayed and that secretion of extracellular matrix components (ECM) is impaired in cog4-/- mutants. These results show that Cog4 is required for secretion of ECM molecules essential to drive the growth of the epithelial projections and thus regulates morphogenesis of the semicircular canals.
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Affiliation(s)
- Aurélie Clément
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | | | - Judy L Peirce
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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26
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Honda A, Kita T, Seshadri SV, Misaki K, Ahmed Z, Ladbury JE, Richardson GP, Yonemura S, Ladher RK. FGFR1-mediated protocadherin-15 loading mediates cargo specificity during intraflagellar transport in inner ear hair-cell kinocilia. Proc Natl Acad Sci U S A 2018; 115:8388-8393. [PMID: 30061390 PMCID: PMC6099903 DOI: 10.1073/pnas.1719861115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The mechanosensory hair cells of the inner ear are required for hearing and balance and have a distinctive apical structure, the hair bundle, that converts mechanical stimuli into electrical signals. This structure comprises a single cilium, the kinocilium, lying adjacent to an ensemble of actin-based projections known as stereocilia. Hair bundle polarity depends on kinociliary protocadherin-15 (Pcdh15) localization. Protocadherin-15 is found only in hair-cell kinocilia, and is not localized to the primary cilia of adjacent supporting cells. Thus, Pcdh15 must be specifically targeted and trafficked into the hair-cell kinocilium. Here we show that kinocilial Pcdh15 trafficking relies on cell type-specific coupling to the generic intraflagellar transport (IFT) transport mechanism. We uncover a role for fibroblast growth factor receptor 1 (FGFR1) in loading Pcdh15 onto kinociliary transport particles in hair cells. We find that on activation, FGFR1 binds and phosphorylates Pcdh15. Moreover, we find a previously uncharacterized role for clathrin in coupling this kinocilia-specific cargo with the anterograde IFT-B complex through the adaptor, DAB2. Our results identify a modified ciliary transport pathway used for Pcdh15 transport into the cilium of the inner ear hair cell and coordinated by FGFR1 activity.
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Affiliation(s)
- Akira Honda
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, 650-0047 Kobe, Japan
| | - Tomoko Kita
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, 650-0047 Kobe, Japan
- Department of Otolaryngology, Head and Neck Surgery, Kyoto University Hospital, 606-8507 Kyoto, Japan
| | | | - Kazuyo Misaki
- Ultrastructural Research Team, RIKEN Center for Life Science Technologies, 650-0047 Kobe, Japan
- Department of Cell Biology, Tokushima University, 770-8503 Tokushima, Japan
| | - Zamal Ahmed
- School of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, United Kingdom
| | - John E Ladbury
- School of Molecular and Cellular Biology, University of Leeds, LS2 9JT Leeds, United Kingdom
- Department of Biochemistry and Molecular Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Center for Biomolecular Structure and Function, University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Guy P Richardson
- Sussex Neuroscience, School of Life Sciences, University of Sussex, BN1 9QG Brighton, United Kingdom
| | - Shigenobu Yonemura
- Ultrastructural Research Team, RIKEN Center for Life Science Technologies, 650-0047 Kobe, Japan
- Department of Cell Biology, Tokushima University, 770-8503 Tokushima, Japan
| | - Raj K Ladher
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, 650-0047 Kobe, Japan;
- National Centre for Biological Sciences, 560-065 Bangalore, India
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27
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Dona M, Slijkerman R, Lerner K, Broekman S, Wegner J, Howat T, Peters T, Hetterschijt L, Boon N, de Vrieze E, Sorusch N, Wolfrum U, Kremer H, Neuhauss S, Zang J, Kamermans M, Westerfield M, Phillips J, van Wijk E. Usherin defects lead to early-onset retinal dysfunction in zebrafish. Exp Eye Res 2018; 173:148-159. [PMID: 29777677 DOI: 10.1016/j.exer.2018.05.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 01/24/2023]
Abstract
Mutations in USH2A are the most frequent cause of Usher syndrome and autosomal recessive nonsyndromic retinitis pigmentosa. To unravel the pathogenic mechanisms underlying USH2A-associated retinal degeneration and to evaluate future therapeutic strategies that could potentially halt the progression of this devastating disorder, an animal model is needed. The available Ush2a knock-out mouse model does not mimic the human phenotype, because it presents with only a mild and late-onset retinal degeneration. Using CRISPR/Cas9-technology, we introduced protein-truncating germline lesions into the zebrafish ush2a gene (ush2armc1: c.2337_2342delinsAC; p.Cys780GlnfsTer32 and ush2ab1245: c.15520_15523delinsTG; p.Ala5174fsTer). Homozygous mutants were viable and displayed no obvious morphological or developmental defects. Immunohistochemical analyses with antibodies recognizing the N- or C-terminal region of the ush2a-encoded protein, usherin, demonstrated complete absence of usherin in photoreceptors of ush2armc1, but presence of the ectodomain of usherin at the periciliary membrane of ush2ab1245-derived photoreceptors. Furthermore, defects of usherin led to a reduction in localization of USH2 complex members, whirlin and Adgrv1, at the photoreceptor periciliary membrane of both mutants. Significantly elevated levels of apoptotic photoreceptors could be observed in both mutants when kept under constant bright illumination for three days. Electroretinogram (ERG) recordings revealed a significant and similar decrease in both a- and b-wave amplitudes in ush2armc1 as well as ush2ab1245 larvae as compared to strain- and age-matched wild-type larvae. In conclusion, this study shows that mutant ush2a zebrafish models present with early-onset retinal dysfunction that is exacerbated by light exposure. These models provide a better understanding of the pathophysiology underlying USH2A-associated RP and a unique opportunity to evaluate future therapeutic strategies.
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Affiliation(s)
- Margo Dona
- Department of Otorhinolaryngology, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 28, 6525 GA Nijmegen, The Netherlands
| | - Ralph Slijkerman
- Department of Otorhinolaryngology, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Geert Grooteplein Zuid 28, 6525 GA Nijmegen, The Netherlands
| | - Kimberly Lerner
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403-1254, USA
| | - Sanne Broekman
- Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Donders Institute for Brain, Cognition, and Behavior, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands
| | - Jeremy Wegner
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403-1254, USA
| | - Taylor Howat
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403-1254, USA
| | - Theo Peters
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403-1254, USA; Donders Institute for Brain, Cognition, and Behavior, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands
| | - Lisette Hetterschijt
- Department of Otorhinolaryngology, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Donders Institute for Brain, Cognition, and Behavior, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands
| | - Nanda Boon
- Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands
| | - Erik de Vrieze
- Department of Otorhinolaryngology, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Donders Institute for Brain, Cognition, and Behavior, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands
| | - Nasrin Sorusch
- Institute of Molecular Physiology, Johannes Gutenberg University, Johannes-von-Muellerweg 6, D-55099 Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University, Johannes-von-Muellerweg 6, D-55099 Mainz, Germany
| | - Hannie Kremer
- Department of Otorhinolaryngology, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Donders Institute for Brain, Cognition, and Behavior, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands
| | - Stephan Neuhauss
- University of Zürich, Institute of Molecular Life Sciences, Winterthurerstrasse 190, Zürich, CH - 8057, Switzerland
| | - Jingjing Zang
- University of Zürich, Institute of Molecular Life Sciences, Winterthurerstrasse 190, Zürich, CH - 8057, Switzerland
| | - Maarten Kamermans
- Retinal Signal Processing Lab, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands; Department of Biomedical Physics, Academisch Medisch Centrum, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Monte Westerfield
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403-1254, USA
| | - Jennifer Phillips
- Institute of Neuroscience, 1254 University of Oregon, Eugene, OR, 97403-1254, USA
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, The Netherlands; Donders Institute for Brain, Cognition, and Behavior, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands.
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Matern MS, Beirl A, Ogawa Y, Song Y, Paladugu N, Kindt KS, Hertzano R. Transcriptomic Profiling of Zebrafish Hair Cells Using RiboTag. Front Cell Dev Biol 2018; 6:47. [PMID: 29765956 PMCID: PMC5939014 DOI: 10.3389/fcell.2018.00047] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/13/2018] [Indexed: 01/27/2023] Open
Abstract
The zebrafish inner ear organs and lateral line neuromasts are comprised of a variety of cell types, including mechanosensitive hair cells. Zebrafish hair cells are evolutionarily homologous to mammalian hair cells, and have been particularly useful for studying normal hair cell development and function. However, the relative scarcity of hair cells within these complex organs, as well as the difficulty of fine dissection at early developmental time points, makes hair cell-specific gene expression profiling technically challenging. Cell sorting methods, as well as single-cell RNA-Seq, have proved to be very informative in studying hair cell-specific gene expression. However, these methods require that tissues are dissociated, the processing for which can lead to changes in gene expression prior to RNA extraction. To bypass this problem, we have developed a transgenic zebrafish model to evaluate the translatome of the inner ear and lateral line hair cells in their native tissue environment; the Tg(myo6b:RiboTag) zebrafish. This model expresses both GFP and a hemagglutinin (HA) tagged rpl10a gene under control of the myo6b promoter (myo6b:GFP-2A-rpl10a-3xHA), resulting in HA-tagged ribosomes expressed specifically in hair cells. Consequently, intact zebrafish larvae can be used to enrich for actively translated hair cell mRNA via an immunoprecipitation protocol using an antibody for the HA-tag (similar to the RiboTag mice). We demonstrate that this model can be used to reliably enrich for actively translated zebrafish hair cell mRNA. Additionally, we perform a global hair cell translatome analysis using RNA-Seq and show enrichment of known hair cell expressed transcripts and depletion of non-hair cell expressed transcripts in the immunoprecipitated material compared with mRNA extracted from whole fish (input). Our results show that our model can identify novel hair cell expressed genes in intact zebrafish, without inducing changes to gene expression that result from tissue dissociation and delays during cell sorting. Overall, we believe that this model will be highly useful for studying changes in zebrafish hair cell-specific gene expression in response to developmental progression, mutations, as well as hair cell damage by noise or ototoxic drug exposure.
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Affiliation(s)
- Maggie S. Matern
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Alisha Beirl
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, Bethesda, MD, United States
| | - Yoko Ogawa
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Yang Song
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Nikhil Paladugu
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Katie S. Kindt
- Section on Sensory Cell Development and Function, National Institute on Deafness and Other Communication Disorders, Bethesda, MD, United States
| | - Ronna Hertzano
- Department of Otorhinolaryngology Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, MD, United States,Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, United States,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States,*Correspondence: Ronna Hertzano
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Endoplasmic Reticulum Stress in Hearing Loss. JOURNAL OF OTORHINOLARYNGOLOGY, HEARING AND BALANCE MEDICINE 2017. [DOI: 10.3390/ohbm1010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Abstract
Our ears are remarkable sensory organs, providing the important senses of balance and hearing. The complex structure of the inner ear, or 'labyrinth', along with the assorted neuroepithelia, have evolved to detect head movements and sounds with impressive sensitivity. The rub is that the inner ear is highly vulnerable to genetic lesions and environmental insults. According to National Institute of Health estimates, hearing loss is one of the most commonly inherited or acquired sensorineural diseases. To understand the causes of deafness and balance disorders, it is imperative to understand the underlying biology of the inner ear, especially the inner workings of the sensory receptors. These receptors, which are termed hair cells, are particularly susceptible to genetic mutations - more than two dozen genes are associated with defects in this cell type in humans. Over the past decade, a substantial amount of progress has been made in working out the molecular basis of hair-cell function using vertebrate animal models. Given the transparency of the inner ear and the genetic tools that are available, zebrafish have become an increasingly popular animal model for the study of deafness and vestibular dysfunction. Mutagenesis screens for larval defects in hearing and balance have been fruitful in finding key components, many of which have been implicated in human deafness. This review will focus on the genes that are required for hair-cell function in zebrafish, with a particular emphasis on mechanotransduction. In addition, the generation of new tools available for the characterization of zebrafish hair-cell mutants will be discussed.
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Affiliation(s)
- Teresa Nicolson
- Oregon Hearing Research Center and the Vollum Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, Tel: 503-494-3693,
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McGowan SE, McCoy DM. Platelet-derived growth factor receptor-α and Ras-related C3 botulinum toxin substrate-1 regulate mechano-responsiveness of lung fibroblasts. Am J Physiol Lung Cell Mol Physiol 2017; 313:L1174-L1187. [PMID: 28775097 DOI: 10.1152/ajplung.00185.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/27/2017] [Accepted: 07/27/2017] [Indexed: 12/23/2022] Open
Abstract
Platelet-derived growth factor (PDGF)-A, which only signals through PDGF-receptor-α (PDGFR-α), is required for secondary alveolar septal formation. Although PDGFR-α distinguishes mesenchymal progenitor cells during the saccular stage, PDGFR-α-expressing alveolar cells persist through adulthood. PDGF-A sustains proliferation, limits apoptosis, and maintains α-smooth muscle actin (α-SMA)-containing alveolar cells, which congregate at the alveolar entry ring at postnatal day (P)12. PDGFR-α-expressing, α-SMA-containing alveolar cells redistribute in the elongating septum, suggesting that they migrate to the alveolar entry rings, where mechanical tension is higher. We hypothesized that PDGFR-α and Ras-related C3 botulinum toxin substrate 1(Rac1) are required for mechanosensitive myofibroblast migration. Spreading of PDGFR-α-deficient lung fibroblasts was insensitive to increased rigidity, and their migration was not reduced by Rac1-guanine exchange factor (GEF)-inhibition. PDGFR-α-expressing fibroblasts migrated toward stiffer regions within two-dimensional substrates by increasing migrational persistence (durotaxis). Using a Förster resonance energy transfer (FRET) biosensor for Rac1-GTP, we observed that PDGFR-α was required for fibroblast Rac1 responsiveness to stiffness within a three-dimensional collagen substrate, which by itself increased Rac1-FRET. Rho-GTPase stabilized, whereas Rac1-GTPase increased the turnover of focal adhesions. Under conditions that increased Rac1-GTP, PDGFR-α signaled through both phosphoinositide-3-kinase (PIK) or Src to engage the Rac1 GEF dedicator of cytokinesis-1 (Dock180) and p21-activated-kinase interacting exchange factor-β (βPIX). In cooperation with collagen fibers, these signaling pathways may guide fibroblasts toward the more rigid alveolar entry ring during secondary septation. Because emphysema and interstitial fibrosis disrupt the parenchymal mechanical continuum, understanding how mechanical factors regulate fibroblast migration could elicit strategies for alveolar repair and regeneration.
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Affiliation(s)
- Stephen E McGowan
- Department of Veterans Affairs Research Service and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Diann M McCoy
- Department of Veterans Affairs Research Service and Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Ding J, Shao L, Yao Y, Tong X, Liu H, Yue S, Xie L, Cheng SY. DGKδ triggers endoplasmic reticulum release of IFT88-containing vesicles destined for the assembly of primary cilia. Sci Rep 2017; 7:5296. [PMID: 28706295 PMCID: PMC5509727 DOI: 10.1038/s41598-017-05680-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 06/01/2017] [Indexed: 11/16/2022] Open
Abstract
The morphogenic factor Sonic hedgehog (Shh) signals through the primary cilium, which relies on intraflagellar transport to maintain its structural integrity and function. However, the process by which protein and lipid cargos are delivered to the primary cilium from their sites of synthesis still remains poorly characterized. Here, we report that diacylglycerol kinase δ (DGKδ), a residential lipid kinase in the endoplasmic reticulum, triggers the release of IFT88-containing vesicles from the ER exit sites (ERES), thereby setting forth their movement to the primary cilium. Encoded by the gene whose mutations originally implicated the primary cilium as the venue of Shh signaling, IFT88 is known to be part of the complex B that drives the anterograde transport within cilia. We show that IFT88 interacts with DGKδ, and is associated with COPII-coated vesicles at the ERES. Using a combination of RNAi silencing and gene knockout strategies, we further show that DGKδ is required for supporting Shh signaling both in vitro and in vivo, demonstrating the physiological significance of this regulation.
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Affiliation(s)
- Jie Ding
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Lei Shao
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Yixing Yao
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Xin Tong
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Huaize Liu
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Shen Yue
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Lu Xie
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China
| | - Steven Y Cheng
- Department of Developmental Genetics, School of Basic Medical Sciences, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China.
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Myosin 7 and its adaptors link cadherins to actin. Nat Commun 2017; 8:15864. [PMID: 28660889 PMCID: PMC5493754 DOI: 10.1038/ncomms15864] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/03/2017] [Indexed: 12/17/2022] Open
Abstract
Cadherin linkages between adjacent stereocilia and microvilli are essential for mechanotransduction and maintaining their organization. They are anchored to actin through interaction of their cytoplasmic domains with related tripartite complexes consisting of a class VII myosin and adaptor proteins: Myo7a/SANS/Harmonin in stereocilia and Myo7b/ANKS4B/Harmonin in microvilli. Here, we determine high-resolution structures of Myo7a and Myo7b C-terminal MyTH4-FERM domain (MF2) and unveil how they recognize harmonin using a novel binding mode. Systematic definition of interactions between domains of the tripartite complex elucidates how the complex assembles and prevents possible self-association of harmonin-a. Several Myo7a deafness mutants that map to the surface of MF2 disrupt harmonin binding, revealing the molecular basis for how they impact the formation of the tripartite complex and disrupt mechanotransduction. Our results also suggest how switching between different harmonin isoforms can regulate the formation of networks with Myo7a motors and coordinate force sensing in stereocilia. Cadherin is essential for mechanotransduction and myosin-adaptor-harmonin complexes anchor it to actin. Here the authors present the structures of myosin 7 MF2 domains bound to the harmonin PDZ3c domain and give insights into myosin-adaptor-harmonin complex assembly.
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Reduced expression of citrate synthase leads to excessive superoxide formation and cell apoptosis. Biochem Biophys Res Commun 2017; 485:388-394. [PMID: 28216161 DOI: 10.1016/j.bbrc.2017.02.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 02/13/2017] [Indexed: 02/04/2023]
Abstract
A/J mice are a mouse model of age-related hearing loss. It has been demonstrated that a mutation in gene of citrate synthase (CS) contributes to the early onset of hearing loss occurring at about one month of age. To understand the effects of a decreased CS activity that results from the mutation in Cs gene on hearing loss in A/J mice, human kidney cell line (293T) was transiently transfected with short hairpin RNA for Cs (shRNA-Cs) to reduce expression of CS. In comparison with those of cells transfected with a scrambled sequence (shRNA-NC), the oxygen consumption rate and adenosine trisphosphate (ATP) production level were decreased in 293T cells transfected with shRNA-Cs. Meanwhile, excessive superoxide production was induced as determined by mitochondrial superoxide formation assay (MitoSOX) and superoxide dismutase 2 (SOD2) detection. Moreover, the expression levels of BIP (binding immunoglobulin protein) and CHOP (CCAAT/enhancer-binding protein-homologous protein), markers of endoplasmic reticulum stress, were upregulated. Furthermore, apoptosis related molecule caspase-3 and the mitochondrial membrane potential were reduced. It is therefore concluded that downregulation of Cs expression in 293T cells leads to low level of ATP production, excessive superoxide formation and cell apoptosis, which implies a possible mechanism for hearing loss in A/J mice.
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36
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ER stress inhibitor attenuates hearing loss and hair cell death in Cdh23 erl/erl mutant mice. Cell Death Dis 2016; 7:e2485. [PMID: 27882946 PMCID: PMC5260868 DOI: 10.1038/cddis.2016.386] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 10/19/2016] [Accepted: 10/24/2016] [Indexed: 12/17/2022]
Abstract
Hearing loss is one of the most common sensory impairments in humans. Mouse mutant models helped us to better understand the mechanisms of hearing loss. Recently, we have discovered that the erlong (erl) mutation of the cadherin23 (Cdh23) gene leads to hearing loss due to hair cell apoptosis. In this study, we aimed to reveal the molecular pathways upstream to apoptosis in hair cells to exploit more effective therapeutics than an anti-apoptosis strategy. Our results suggest that endoplasmic reticulum (ER) stress is the earliest molecular event leading to the apoptosis of hair cells and hearing loss in erl mice. We also report that the ER stress inhibitor, Salubrinal (Sal), could delay the progression of hearing loss and preserve hair cells. Our results provide evidence that therapies targeting signaling pathways in ER stress development prevent hair cell apoptosis at an early stage and lead to better outcomes than those targeting downstream factors, such as tip-link degeneration and apoptosis.
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Cilia-Associated Genes Play Differing Roles in Aminoglycoside-Induced Hair Cell Death in Zebrafish. G3-GENES GENOMES GENETICS 2016; 6:2225-35. [PMID: 27207957 PMCID: PMC4938675 DOI: 10.1534/g3.116.030080] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Hair cells possess a single primary cilium, called the kinocilium, early in development. While the kinocilium is lost in auditory hair cells of most species it is maintained in vestibular hair cells. It has generally been believed that the primary role of the kinocilium and cilia-associated genes in hair cells is in the establishment of the polarity of actin-based stereocilia, the hair cell mechanotransduction apparatus. Through genetic screening and testing of candidate genes in zebrafish (Danio rerio) we have found that mutations in multiple cilia genes implicated in intraflagellar transport (dync2h1, wdr35, ift88, and traf3ip), and the ciliary transition zone (cc2d2a, mks1, and cep290) lead to resistance to aminoglycoside-induced hair cell death. These genes appear to have differing roles in hair cells, as mutations in intraflagellar transport genes, but not transition zone genes, lead to defects in kinocilia formation and processes dependent upon hair cell mechanotransduction activity. These mutants highlight a novel role of cilia-associated genes in hair cells, and provide powerful tools for further study.
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Li T, Fan J, Blanco-Sánchez B, Giagtzoglou N, Lin G, Yamamoto S, Jaiswal M, Chen K, Zhang J, Wei W, Lewis MT, Groves AK, Westerfield M, Jia J, Bellen HJ. Ubr3, a Novel Modulator of Hh Signaling Affects the Degradation of Costal-2 and Kif7 through Poly-ubiquitination. PLoS Genet 2016; 12:e1006054. [PMID: 27195754 PMCID: PMC4873228 DOI: 10.1371/journal.pgen.1006054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 04/25/2016] [Indexed: 12/21/2022] Open
Abstract
Hedgehog (Hh) signaling regulates multiple aspects of metazoan development and tissue homeostasis, and is constitutively active in numerous cancers. We identified Ubr3, an E3 ubiquitin ligase, as a novel, positive regulator of Hh signaling in Drosophila and vertebrates. Hh signaling regulates the Ubr3-mediated poly-ubiquitination and degradation of Cos2, a central component of Hh signaling. In developing Drosophila eye discs, loss of ubr3 leads to a delayed differentiation of photoreceptors and a reduction in Hh signaling. In zebrafish, loss of Ubr3 causes a decrease in Shh signaling in the developing eyes, somites, and sensory neurons. However, not all tissues that require Hh signaling are affected in zebrafish. Mouse UBR3 poly-ubiquitinates Kif7, the mammalian homologue of Cos2. Finally, loss of UBR3 up-regulates Kif7 protein levels and decreases Hh signaling in cultured cells. In summary, our work identifies Ubr3 as a novel, evolutionarily conserved modulator of Hh signaling that boosts Hh in some tissues.
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Affiliation(s)
- Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Junkai Fan
- Markey Cancer Center and Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | | | - Nikolaos Giagtzoglou
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jie Zhang
- Markey Cancer Center and Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Wei Wei
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michael T. Lewis
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Andrew K. Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America
| | - Jianhang Jia
- Markey Cancer Center and Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Hugo J. Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Han F, Wang O, Cai Q. Anti-apoptotic treatment in mouse models of age-related hearing loss. J Otol 2016; 11:7-12. [PMID: 29937804 PMCID: PMC6002598 DOI: 10.1016/j.joto.2016.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/22/2016] [Accepted: 03/24/2016] [Indexed: 01/05/2023] Open
Abstract
Age-related hearing loss (AHL), or presbycusis, is the most common neurodegenerative disorder and top communication deficit of the aged population. Genetic predisposition is one of the major factors in the development of AHL. Generally, AHL is associated with an age-dependent loss of sensory hair cells, spiral ganglion neurons and stria vascularis cells in the inner ear. Although the mechanisms leading to genetic hearing loss are not completely understood, caspase-family proteases function as important signals in the inner ear pathology. It is now accepted that mouse models are the best tools to study the mechanism of genetic hearing loss or AHL. Here, we provide a brief review of recent studies on hearing improvement in mouse models of AHL by anti-apoptotic treatment.
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Affiliation(s)
- Fengchan Han
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
- Institute of Neurobiology, School of Special Education, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
- Corresponding author. Key Laboratory for Genetic Hearing Disorders in Shandong, and Institute of Neurobiology, School of Special Education, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China.
| | - Oumei Wang
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
- Institute of Neurobiology, School of Special Education, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
| | - Quanxiang Cai
- Key Laboratory for Genetic Hearing Disorders in Shandong, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
- Institute of Neurobiology, School of Special Education, Binzhou Medical University, 346 Guanhai Road, Yantai 264003, Shandong, PR China
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The unconventional myosin CRINKLED and its mammalian orthologue MYO7A regulate caspases in their signalling roles. Nat Commun 2016; 7:10972. [PMID: 26960254 PMCID: PMC4792956 DOI: 10.1038/ncomms10972] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 02/05/2016] [Indexed: 12/25/2022] Open
Abstract
Caspases provide vital links in non-apoptotic regulatory networks controlling inflammation, compensatory proliferation, morphology and cell migration. How caspases are activated under non-apoptotic conditions and process a selective set of substrates without killing the cell remain enigmatic. Here we find that the Drosophila unconventional myosin CRINKLED (CK) selectively interacts with the initiator caspase DRONC and regulates some of its non-apoptotic functions. Loss of CK in the arista, border cells or proneural clusters of the wing imaginal discs affects DRONC-dependent patterning. Our data indicate that CK acts as substrate adaptor, recruiting SHAGGY46/GSK3-β to DRONC, thereby facilitating caspase-mediated cleavage and localized modulation of kinase activity. Similarly, the mammalian CK counterpart, MYO7A, binds to and impinges on CASPASE-8, revealing a new regulatory axis affecting receptor interacting protein kinase-1 (RIPK1)>CASPASE-8 signalling. Together, our results expose a conserved role for unconventional myosins in transducing caspase-dependent regulation of kinases, allowing them to take part in specific signalling events.
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Zebrafish Models for the Mechanosensory Hair Cell Dysfunction in Usher Syndrome 3 Reveal That Clarin-1 Is an Essential Hair Bundle Protein. J Neurosci 2015; 35:10188-201. [PMID: 26180195 DOI: 10.1523/jneurosci.1096-15.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Usher syndrome type III (USH3) is characterized by progressive loss of hearing and vision, and varying degrees of vestibular dysfunction. It is caused by mutations that affect the human clarin-1 protein (hCLRN1), a member of the tetraspanin protein family. The missense mutation CLRN1(N48K), which affects a conserved N-glycosylation site in hCLRN1, is a common causative USH3 mutation among Ashkenazi Jews. The affected individuals hear at birth but lose that function over time. Here, we developed an animal model system using zebrafish transgenesis and gene targeting to provide an explanation for this phenotype. Immunolabeling demonstrated that Clrn1 localized to the hair cell bundles (hair bundles). The clrn1 mutants generated by zinc finger nucleases displayed aberrant hair bundle morphology with diminished function. Two transgenic zebrafish that express either hCLRN1 or hCLRN1(N48K) in hair cells were produced to examine the subcellular localization patterns of wild-type and mutant human proteins. hCLRN1 localized to the hair bundles similarly to zebrafish Clrn1; in contrast, hCLRN1(N48K) largely mislocalized to the cell body with a small amount reaching the hair bundle. We propose that this small amount of hCLRN1(N48K) in the hair bundle provides clarin-1-mediated function during the early stages of life; however, the presence of hCLRN1(N48K) in the hair bundle diminishes over time because of intracellular degradation of the mutant protein, leading to progressive loss of hair bundle integrity and hair cell function. These findings and genetic tools provide an understanding and path forward to identify therapies to mitigate hearing loss linked to the CLRN1 mutation. SIGNIFICANCE STATEMENT Mutations in the clarin-1 gene affect eye and ear function in humans. Individuals with the CLRN1(N48K) mutation are born able to hear but lose that function over time. Here, we develop an animal model system using zebrafish transgenesis and gene targeting to provide an explanation for this phenotype. This approach illuminates the role of clarin-1 and the molecular mechanism linked to the CLRN1(N48K) mutation in sensory hair cells of the inner ear. Additionally, the investigation provided an in vivo model to guide future drug discovery to rescue the hCLRN1(N48K) in hair cells.
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Whitfield TT. Development of the inner ear. Curr Opin Genet Dev 2015; 32:112-8. [DOI: 10.1016/j.gde.2015.02.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/11/2015] [Accepted: 02/13/2015] [Indexed: 02/04/2023]
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Mathur P, Yang J. Usher syndrome: Hearing loss, retinal degeneration and associated abnormalities. Biochim Biophys Acta Mol Basis Dis 2014; 1852:406-20. [PMID: 25481835 DOI: 10.1016/j.bbadis.2014.11.020] [Citation(s) in RCA: 222] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 02/06/2023]
Abstract
Usher syndrome (USH), clinically and genetically heterogeneous, is the leading genetic cause of combined hearing and vision loss. USH is classified into three types, based on the hearing and vestibular symptoms observed in patients. Sixteen loci have been reported to be involved in the occurrence of USH and atypical USH. Among them, twelve have been identified as causative genes and one as a modifier gene. Studies on the proteins encoded by these USH genes suggest that USH proteins interact among one another and function in multiprotein complexes in vivo. Although their exact functions remain enigmatic in the retina, USH proteins are required for the development, maintenance and function of hair bundles, which are the primary mechanosensitive structure of inner ear hair cells. Despite the unavailability of a cure, progress has been made to develop effective treatments for this disease. In this review, we focus on the most recent discoveries in the field with an emphasis on USH genes, protein complexes and functions in various tissues as well as progress toward therapeutic development for USH.
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Affiliation(s)
- Pranav Mathur
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA; Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA; Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA; Department of Otolaryngology Head and Neck Surgery, University of Utah, Salt Lake City, UT 84132, USA.
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