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Pedro De-la-Torre, Wen H, Brower J, Martínez-Pérez K, Narui Y, Yeh F, Hale E, Ivanchenko MV, Corey DP, Sotomayor M, Indzhykulian AA. Elasticity and Thermal Stability are Key Determinants of Hearing Rescue by Mini-Protocadherin-15 Proteins. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.16.599132. [PMID: 38948700 PMCID: PMC11212938 DOI: 10.1101/2024.06.16.599132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Protocadherin-15 is a core protein component of inner-ear hair-cell tip links pulling on transduction channels essential for hearing and balance. Protocadherin-15 defects can result in non-syndromic deafness or Usher syndrome type 1F (USH1F) with hearing loss, balance deficits, and progressive blindness. Three rationally engineered shortened versions of protocadherin-15 (mini-PCDH15s) amenable for gene therapy have been used to rescue function in USH1F mouse models. Two can successfully or partially rescue hearing, while another one fails. Here we show that despite varying levels of hearing rescue, all three mini-PCDH15 versions can rescue hair-cell mechanotransduction. Negative-stain electron microscopy shows that all three versions form dimers like the wild-type protein, while crystal structures of some engineered fragments show that these can properly fold and bind calcium ions essential for function. In contrast, simulations predict distinct elasticities and nano differential scanning fluorimetry shows differences in melting temperature measurements. Our data suggest that elasticity and thermal stability are key determinants of sustained hearing rescue by mini-PCDH15s.
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Affiliation(s)
- Pedro De-la-Torre
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Haosheng Wen
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
- Biophysics Program, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
| | - Joseph Brower
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Karina Martínez-Pérez
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Biology Program, Department of Basic Sciences, Universidad del Atlántico, Cra 30 # 8-49, Puerto Colombia, 081007, Colombia
| | - Yoshie Narui
- Center for Electron Microscopy and Analysis, The Ohio State University, 1275-1305 Kinnear Road, Columbus, OH, USA
| | - Frank Yeh
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
| | - Evan Hale
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Speech and Hearing Biosciences and Technology graduate program, Harvard University, Cambridge, MA, USA
| | - Maryna V. Ivanchenko
- Department of Neurobiology, Harvard Medical School, 200 Longwood Ave, Boston, MA, USA
| | - David P. Corey
- Department of Neurobiology, Harvard Medical School, 200 Longwood Ave, Boston, MA, USA
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
- Biophysics Program, The Ohio State University, 484 W. 12th Avenue, Columbus, OH, USA
| | - Artur A. Indzhykulian
- Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, 243 Charles St, Boston, MA, USA
- Speech and Hearing Biosciences and Technology graduate program, Harvard University, Cambridge, MA, USA
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2
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Yusuf IH, Burgoyne T, Salman A, McClements ME, MacLaren RE, Charbel Issa P. Rescue of cone and rod photoreceptor function in a CDHR1-model of age-related retinal degeneration. Mol Ther 2024; 32:1445-1460. [PMID: 38504520 PMCID: PMC11081940 DOI: 10.1016/j.ymthe.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/22/2024] [Accepted: 03/15/2024] [Indexed: 03/21/2024] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of untreatable blindness in the developed world. Recently, CDHR1 has been identified as the cause of a subset of AMD that has the appearance of the "dry" form, or geographic atrophy. Biallelic variants in CDHR1-a specialized protocadherin highly expressed in cone and rod photoreceptors-result in blindness from shortened photoreceptor outer segments and progressive photoreceptor cell death. Here we demonstrate long-term morphological, ultrastructural, functional, and behavioral rescue following CDHR1 gene therapy in a relevant murine model, sustained to 23-months after injection. This represents the first demonstration of rescue of a monogenic cadherinopathy in vivo. Moreover, the durability of CDHR1 gene therapy seems to be near complete-with morphological findings of the rescued retina not obviously different from wildtype throughout the lifespan of the mouse model. A follow-on clinical trial in patients with CDHR1-associated retinal degeneration is warranted. Hypomorphic CDHR1 variants may mimic advanced dry AMD. Accurate clinical classification is now critical, as their pathogenesis and treatment are distinct.
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Affiliation(s)
- Imran H Yusuf
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford OX3 9DU, UK
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Ahmed Salman
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford OX3 9DU, UK.
| | - Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK; Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Headley Way, Oxford OX3 9DU, UK.
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3
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Willsey HR, Seaby EG, Godwin A, Ennis S, Guille M, Grainger RM. Modelling human genetic disorders in Xenopus tropicalis. Dis Model Mech 2024; 17:dmm050754. [PMID: 38832520 PMCID: PMC11179720 DOI: 10.1242/dmm.050754] [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] [Indexed: 06/05/2024] Open
Abstract
Recent progress in human disease genetics is leading to rapid advances in understanding pathobiological mechanisms. However, the sheer number of risk-conveying genetic variants being identified demands in vivo model systems that are amenable to functional analyses at scale. Here we provide a practical guide for using the diploid frog species Xenopus tropicalis to study many genes and variants to uncover conserved mechanisms of pathobiology relevant to human disease. We discuss key considerations in modelling human genetic disorders: genetic architecture, conservation, phenotyping strategy and rigour, as well as more complex topics, such as penetrance, expressivity, sex differences and current challenges in the field. As the patient-driven gene discovery field expands significantly, the cost-effective, rapid and higher throughput nature of Xenopus make it an essential member of the model organism armamentarium for understanding gene function in development and in relation to disease.
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Affiliation(s)
- Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, Weill Institute for Neurosciences, University of California San Francisco, San Francisco, CA 94158, USA
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA 94518, USA
| | - Eleanor G Seaby
- Genomic Informatics Group, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Annie Godwin
- European Xenopus Resource Centre (EXRC), School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
| | - Sarah Ennis
- Genomic Informatics Group, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Matthew Guille
- European Xenopus Resource Centre (EXRC), School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
| | - Robert M Grainger
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
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4
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Sharkova M, Aparicio G, Mouzaaber C, Zolessi FR, Hocking JC. Photoreceptor calyceal processes accompany the developing outer segment, adopting a stable length despite a dynamic core. J Cell Sci 2024; 137:jcs261721. [PMID: 38477343 PMCID: PMC11058337 DOI: 10.1242/jcs.261721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
Vertebrate photoreceptors detect light through a large cilium-based outer segment, which is filled with photopigment-laden membranous discs. Surrounding the base of the outer segment are microvilli-like calyceal processes (CPs). Although CP disruption has been associated with altered outer segment morphology and photoreceptor degeneration, the role of the CPs remains elusive. Here, we used zebrafish as a model to characterize CPs. We quantified CP parameters and report a strong disparity in outer segment coverage between photoreceptor subtypes. CP length is stable across light and dark conditions, yet heat-shock inducible expression of tagged actin revealed rapid turnover of the CP actin core. Detailed imaging of the embryonic retina uncovered substantial remodeling of the developing photoreceptor apical surface, including a transition from dynamic tangential processes to vertically oriented CPs immediately prior to outer segment formation. Remarkably, we also found a direct connection between apical extensions of the Müller glia and retinal pigment epithelium, arranged as bundles around the ultraviolet sensitive cones. In summary, our data characterize the structure, development and surrounding environment of photoreceptor microvilli in the zebrafish retina.
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Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Gonzalo Aparicio
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, 11400, Uruguay
- Institut Pasteur Montevideo, Uruguay
| | - Constantin Mouzaaber
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Flavio R. Zolessi
- Sección Biología Celular, Facultad de Ciencias, Universidad de la República, 11400, Uruguay
- Institut Pasteur Montevideo, Uruguay
| | - Jennifer C. Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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5
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McDonald A, Wijnholds J. Retinal Ciliopathies and Potential Gene Therapies: A Focus on Human iPSC-Derived Organoid Models. Int J Mol Sci 2024; 25:2887. [PMID: 38474133 DOI: 10.3390/ijms25052887] [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: 01/26/2024] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
The human photoreceptor function is dependent on a highly specialised cilium. Perturbation of cilial function can often lead to death of the photoreceptor and loss of vision. Retinal ciliopathies are a genetically diverse range of inherited retinal disorders affecting aspects of the photoreceptor cilium. Despite advances in the understanding of retinal ciliopathies utilising animal disease models, they can often lack the ability to accurately mimic the observed patient phenotype, possibly due to structural and functional deviations from the human retina. Human-induced pluripotent stem cells (hiPSCs) can be utilised to generate an alternative disease model, the 3D retinal organoid, which contains all major retinal cell types including photoreceptors complete with cilial structures. These retinal organoids facilitate the study of disease mechanisms and potential therapies in a human-derived system. Three-dimensional retinal organoids are still a developing technology, and despite impressive progress, several limitations remain. This review will discuss the state of hiPSC-derived retinal organoid technology for accurately modelling prominent retinal ciliopathies related to genes, including RPGR, CEP290, MYO7A, and USH2A. Additionally, we will discuss the development of novel gene therapy approaches targeting retinal ciliopathies, including the delivery of large genes and gene-editing techniques.
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Affiliation(s)
- Andrew McDonald
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, The Netherlands
| | - Jan Wijnholds
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, The Netherlands
- Netherlands Institute of Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), 1105 BA Amsterdam, The Netherlands
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6
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Riaz S, Sethna S, Duncan T, Naeem MA, Redmond TM, Riazuddin S, Riazuddin S, Carvalho LS, Ahmed ZM. Dual AAV-based PCDH15 gene therapy achieves sustained rescue of visual function in a mouse model of Usher syndrome 1F. Mol Ther 2023; 31:3490-3501. [PMID: 37864333 PMCID: PMC10727994 DOI: 10.1016/j.ymthe.2023.10.017] [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: 06/15/2023] [Revised: 09/20/2023] [Accepted: 10/18/2023] [Indexed: 10/22/2023] Open
Abstract
Mutations in the PCDH15 gene, encoding protocadherin-15, are among the leading causes of Usher syndrome type 1 (USH1F), and account for up to 12% USH1 cases worldwide. A founder truncating variant of PCDH15 has a ∼2% carrier frequency in Ashkenazi Jews accounting for nearly 60% of their USH1 cases. Although cochlear implants can restore hearing perception in USH1 patients, presently there are no effective treatments for the vision loss due to retinitis pigmentosa. We established a founder allele-specific Pcdh15 knockin mouse model as a platform to ascertain therapeutic strategies. Using a dual-vector approach to circumvent the size limitation of adeno-associated virus, we observed robust expression of exogenous PCDH15 in the retinae of Pcdh15KI mice, sustained recovery of electroretinogram amplitudes and key retinoid oxime, substantially improved light-dependent translocation of phototransduction proteins, and enhanced levels of retinal pigment epithelium-derived enzymes. Thus, our data raise hope and pave the way for future gene therapy trials in USH1F subjects.
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Affiliation(s)
- Sehar Riaz
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - Saumil Sethna
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Muhammad A Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54500, Pakistan
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sheikh Riazuddin
- Jinnah Burn and Reconstructive Surgery Centre, Allama Iqbal Medical Research, University of Health Sciences, Lahore 54500, Pakistan
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Livia S Carvalho
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA 6009, Australia; Retinal Genomics and Therapy Group, Lions Eye Institute Ltd, Nedlands, WA 6009, Australia
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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7
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Gilmore WB, Hultgren NW, Chadha A, Barocio SB, Zhang J, Kutsyr O, Flores-Bellver M, Canto-Soler MV, Williams DS. Expression of two major isoforms of MYO7A in the retina: Considerations for gene therapy of Usher syndrome type 1B. Vision Res 2023; 212:108311. [PMID: 37586294 PMCID: PMC10984346 DOI: 10.1016/j.visres.2023.108311] [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: 05/03/2023] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 08/18/2023]
Abstract
Usher syndrome type 1B (USH1B) is a deaf-blindness disorder, caused by mutations in the MYO7A gene, which encodes the heavy chain of an unconventional actin-based motor protein. Here, we examined the two retinal isoforms of MYO7A, IF1 and IF2. We compared 3D models of the two isoforms and noted that the 38-amino acid region that is present in IF1 but absent from IF2 affects the C lobe of the FERM1 domain and the opening of a cleft in this potentially important protein binding domain. Expression of each of the two isoforms of human MYO7A and pig and mouse Myo7a was detected in the RPE and neural retina. Quantification by qPCR showed that the expression of IF2 was typically ∼ 7-fold greater than that of IF1. We discuss the implications of these findings for any USH1B gene therapy strategy. Given the current incomplete knowledge of the functions of each isoform, both isoforms should be considered for targeting both the RPE and the neural retina in gene augmentation therapies.
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Affiliation(s)
- W Blake Gilmore
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Nan W Hultgren
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Abhishek Chadha
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sonia B Barocio
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Joyce Zhang
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Oksana Kutsyr
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, CO, USA
| | - Miguel Flores-Bellver
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, CO, USA
| | - M Valeria Canto-Soler
- CellSight Ocular Stem Cell and Regeneration Research Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, CO, USA
| | - David S Williams
- Department of Ophthalmology and Stein Eye Institute, Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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8
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Shamshad A, Kang C, Jenny LA, Persad-Paisley EM, Tsang SH. Translatability barriers between preclinical and clinical trials of AAV gene therapy in inherited retinal diseases. Vision Res 2023; 210:108258. [PMID: 37244011 PMCID: PMC10526971 DOI: 10.1016/j.visres.2023.108258] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/02/2023] [Accepted: 05/09/2023] [Indexed: 05/29/2023]
Abstract
Inherited retinal diseases (IRDs) are progressive degenerative diseases which cause gradual vision loss or complete blindness. As over 270 gene mutations have been identified in the underlying pathology of IRDs, gene therapy as a treatment modality has been an increasingly active realm of investigation. Currently, the most common vehicle of ocular gene delivery is the adeno-associated virus (AAV) vector. This is injected into the immune-privileged subretinal space to mediate transgene expression in retinal cells. Although numerous animal models of IRDs have demonstrated successful outcomes following AAV-mediated gene delivery, many of these studies fail to translate into successful outcomes in clinical trials. The purpose of this review is to A) comparatively assess preclinical and clinical IRD trials in which the success of AAV-mediated therapy failed to translate between animal and human participants B) discuss factors which may complicate the translatability of gene therapy in animals to results in humans.
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Affiliation(s)
| | - Chaerim Kang
- Warren Alpert Medical School of Brown University, USA
| | - Laura A Jenny
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, NY, USA; Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA
| | | | - Stephen H Tsang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, NY, USA; Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, NY, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY, USA; Department of Biomedical Engineering, Columbia University, New York, NY, USA; Columbia Stem Cell Initiative, Columbia University, New York, NY, USA; Insitute of Human Nutrition, Columbia University, New York, NY, USA
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9
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Peters CW, Hanlon KS, Ivanchenko MV, Zinn E, Linarte EF, Li Y, Levy JM, Liu DR, Kleinstiver BP, Indzhykulian AA, Corey DP. Rescue of hearing by adenine base editing in a humanized mouse model of Usher syndrome type 1F. Mol Ther 2023; 31:2439-2453. [PMID: 37312453 PMCID: PMC10421997 DOI: 10.1016/j.ymthe.2023.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 04/03/2023] [Accepted: 06/08/2023] [Indexed: 06/15/2023] Open
Abstract
Usher syndrome type 1F (USH1F), characterized by congenital lack of hearing and balance and progressive loss of vision, is caused by mutations in the PCDH15 gene. In the Ashkenazi population, a recessive truncation mutation accounts for a large proportion of USH1F cases. The truncation is caused by a single C→T mutation, which converts an arginine codon to a stop (R245X). To test the potential for base editors to revert this mutation, we developed a humanized Pcdh15R245X mouse model for USH1F. Mice homozygous for the R245X mutation were deaf and exhibited profound balance deficits, while heterozygous mice were unaffected. Here we show that an adenine base editor (ABE) is capable of reversing the R245X mutation to restore the PCDH15 sequence and function. We packaged a split-intein ABE into dual adeno-associated virus (AAV) vectors and delivered them into cochleas of neonatal USH1F mice. Hearing was not restored in a Pcdh15 constitutive null mouse despite base editing, perhaps because of early disorganization of cochlear hair cells. However, injection of vectors encoding the split ABE into a late-deletion conditional Pcdh15 knockout rescued hearing. This study demonstrates the ability of an ABE to correct the PCDH15 R245X mutation in the cochlea and restore hearing.
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Affiliation(s)
- Cole W Peters
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Killian S Hanlon
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Eric Zinn
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | | | - Yaqiao Li
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jonathan M Levy
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Benjamin P Kleinstiver
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Artur A Indzhykulian
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Otolaryngology - Head and Neck Surgery, Harvard Medical School and Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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10
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Sharkova M, Chow E, Erickson T, Hocking JC. The morphological and functional diversity of apical microvilli. J Anat 2023; 242:327-353. [PMID: 36281951 PMCID: PMC9919547 DOI: 10.1111/joa.13781] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/30/2022] Open
Abstract
Sensory neurons use specialized apical processes to perceive external stimuli and monitor internal body conditions. The apical apparatus can include cilia, microvilli, or both, and is adapted for the functions of the particular cell type. Photoreceptors detect light through a large, modified cilium (outer segment), that is supported by a surrounding ring of microvilli-like calyceal processes (CPs). Although first reported 150 years ago, CPs remain poorly understood. As a basis for future study, we therefore conducted a review of existing literature about sensory cell microvilli, which can act either as the primary sensory detector or as support for a cilia-based detector. While all microvilli are finger-like cellular protrusions with an actin core, the processes vary across cell types in size, number, arrangement, dynamics, and function. We summarize the current state of knowledge about CPs and the characteristics of the microvilli found on inner ear hair cells (stereocilia) and cerebral spinal fluid-contacting neurons, with comparisons to the brush border of the intestinal and renal epithelia. The structure, stability, and dynamics of the actin core are regulated by a complement of actin-binding proteins, which includes both common components and unique features when compared across cell types. Further, microvilli are often supported by lateral links, a glycocalyx, and a defined extracellular matrix, each adapted to the function and environment of the cell. Our comparison of microvillar features will inform further research into how CPs support photoreceptor function, and also provide a general basis for investigations into the structure and functions of apical microvilli found on sensory neurons.
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Affiliation(s)
- Maria Sharkova
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Erica Chow
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Jennifer C Hocking
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Division of Anatomy, Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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11
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Boye SE, Durham T, Laster A, Gelfman CM, Sahel JA. Identifying and Overcoming Challenges in Developing Effective Treatments for Usher 1B: A Workshop Report. Transl Vis Sci Technol 2023; 12:2. [PMID: 36723965 PMCID: PMC9904327 DOI: 10.1167/tvst.12.2.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Purpose To identify challenges and opportunities for the development of treatments for Usher syndrome (USH) type 1B. Methods In September 2021, the Foundation Fighting Blindness hosted a virtual workshop of clinicians, academic and industry researchers, advocates, and affected individuals and their families to discuss the challenges and opportunities for USH1B treatment development. Results The workshop began with insights from individuals affected by USH1B. Presentation topics included myosin VIIA protein function in the ear and eye and its role in disease pathology; challenges with the USH1B mouse model most used in disease research to date; new investigations into alternative disease models that may provide closer analogues to USH1B in the human retina, including retinal organoids and large animal models; and learnings from and limitations of available disease natural history data. Participants discussed the need for an open dialogue between researchers and regulators to design USH1B clinical trials with appropriate outcome measures of vision improvement, along with multimodal imaging of the retina and other testing approaches that can help inform trial designs. The workshop concluded with presentations and a roundtable reviewing emerging treatments, including USH1B-targeted genetic augmentation therapy and gene-agnostic approaches. Conclusions Initiatives like this workshop are important to foster all stakeholders in support of achieving the shared goal of treating and curing USH1B. Translational Relevance Presentations and discussions focused on overcoming disease modeling and clinical trial design challenges to facilitate development, testing, and implementation of effective USH1B treatments.
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Affiliation(s)
- Shannon E. Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA,Atsena Therapeutics, Inc., Durham, NC, USA
| | - Todd Durham
- Foundation Fighting Blindness, Columbia, MD, USA
| | - Amy Laster
- Foundation Fighting Blindness, Columbia, MD, USA
| | | | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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12
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Sato K, Liu Y, Yamashita T, Ohuchi H. The medaka mutant deficient in eyes shut homolog exhibits opsin transport defects and enhanced autophagy in retinal photoreceptors. Cell Tissue Res 2023; 391:249-267. [PMID: 36418571 DOI: 10.1007/s00441-022-03702-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 11/03/2022] [Indexed: 11/27/2022]
Abstract
Eyes shut homolog (EYS) encodes a proteoglycan and the human mutation causes retinitis pigmentosa type 25 (RP25) with progressive retinal degeneration. RP25 most frequently affects autosomal recessive RP patients with many ethnic backgrounds. Although studies using RP models have facilitated the development of therapeutic medications, Eys has been lost in rodent model animals. Here we examined the roles for Eys in the maintenance of photoreceptor structure and function by generating eys-null medaka fish using the CRISPR-Cas9 system. Medaka EYS protein was present near the connecting cilium of wild-type photoreceptors, while it was absent from the eys-/- retina. The mutant larvae exhibited a reduced visual motor response compared with wild-type. In contrast to reported eys-deficient zebrafish at the similar stage, no retinal cell death was detected in the 8-month post-hatching (8-mph) medaka eys mutant. Immunohistochemistry showed a significant reduction in the length of cone outer segments (OSs), retention of OS proteins in the inner segments of photoreceptors, and abnormal filamentous actin network at the base of cone OSs in the mutant retina by 8 mph. Electron microscopy revealed aberrant structure of calyceal processes, numerous vesiculation and lamellar interruptions, and autophagosomes in the eys-mutant cone photoreceptors. In situ hybridization showed an autophagy component gene, gabarap, was ectopically expressed in the eys-null retina. These results suggest eys is required for regeneration of OS, especially of cone photoreceptors, and transport of OS proteins by regulating actin filaments. Enhanced autophagy may delay the progression of retinal degeneration when lacking EYS in the medaka retina.
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Affiliation(s)
- Keita Sato
- Department of Cytology and Histology, Faculty of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan.
| | - Yang Liu
- Department of Cytology and Histology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Hideyo Ohuchi
- Department of Cytology and Histology, Faculty of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama, 700-8558, Japan.
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13
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Nagel-Wolfrum K, Fadl BR, Becker MM, Wunderlich KA, Schäfer J, Sturm D, Fritze J, Gür B, Kaplan L, Andreani T, Goldmann T, Brooks M, Starostik MR, Lokhande A, Apel M, Fath KR, Stingl K, Kohl S, DeAngelis MM, Schlötzer-Schrehardt U, Kim IK, Owen LA, Vetter JM, Pfeiffer N, Andrade-Navarro MA, Grosche A, Swaroop A, Wolfrum U. Expression and subcellular localization of USH1C/harmonin in human retina provides insights into pathomechanisms and therapy. Hum Mol Genet 2023; 32:431-449. [PMID: 35997788 PMCID: PMC9851744 DOI: 10.1093/hmg/ddac211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 01/24/2023] Open
Abstract
Usher syndrome (USH) is the most common form of hereditary deaf-blindness in humans. USH is a complex genetic disorder, assigned to three clinical subtypes differing in onset, course and severity, with USH1 being the most severe. Rodent USH1 models do not reflect the ocular phenotype observed in human patients to date; hence, little is known about the pathophysiology of USH1 in the human eye. One of the USH1 genes, USH1C, exhibits extensive alternative splicing and encodes numerous harmonin protein isoforms that function as scaffolds for organizing the USH interactome. RNA-seq analysis of human retinae uncovered harmonin_a1 as the most abundant transcript of USH1C. Bulk RNA-seq analysis and immunoblotting showed abundant expression of harmonin in Müller glia cells (MGCs) and retinal neurons. Furthermore, harmonin was localized in the terminal endfeet and apical microvilli of MGCs, presynaptic region (pedicle) of cones and outer segments (OS) of rods as well as at adhesive junctions between MGCs and photoreceptor cells (PRCs) in the outer limiting membrane (OLM). Our data provide evidence for the interaction of harmonin with OLM molecules in PRCs and MGCs and rhodopsin in PRCs. Subcellular expression and colocalization of harmonin correlate with the clinical phenotype observed in USH1C patients. We also demonstrate that primary cilia defects in USH1C patient-derived fibroblasts could be reverted by the delivery of harmonin_a1 transcript isoform. Our studies thus provide novel insights into PRC cell biology, USH1C pathophysiology and development of gene therapy treatment(s).
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Affiliation(s)
- Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Benjamin R Fadl
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mirjana M Becker
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Kirsten A Wunderlich
- Department of Physiological Genomics, BioMedical Center, Ludwig-Maximilian University Munich, 82152 Planegg-Martinsried, Germany
| | - Jessica Schäfer
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Daniel Sturm
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Jacques Fritze
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Burcu Gür
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Lew Kaplan
- Department of Physiological Genomics, BioMedical Center, Ludwig-Maximilian University Munich, 82152 Planegg-Martinsried, Germany
| | - Tommaso Andreani
- Computational Biology and Data Mining, Institute of Organismic & Molecular Evolution Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Tobias Goldmann
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Matthew Brooks
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Margaret R Starostik
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anagha Lokhande
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Melissa Apel
- Department of Ophthalmology, University Medical Centre Mainz, 55131 Mainz, Germany
| | - Karl R Fath
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Department of Biology, Queens College of CUNY, Kissena Blvd, Flushing, NY 11367, USA
| | - Katarina Stingl
- University Eye Hospital, Centre for Ophthalmology, University of Tubingen, 72076 Tubingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tubingen, 72076 Tubingen, Germany
| | - Margaret M DeAngelis
- Department of Ophthalmology and Ira G. Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, NY 14209, USA
| | | | - Ivana K Kim
- Retina Service, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Leah A Owen
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT 84132, USA
| | - Jan M Vetter
- Department of Ophthalmology, University Medical Centre Mainz, 55131 Mainz, Germany
| | - Norbert Pfeiffer
- Department of Ophthalmology, University Medical Centre Mainz, 55131 Mainz, Germany
| | - Miguel A Andrade-Navarro
- Computational Biology and Data Mining, Institute of Organismic & Molecular Evolution Biology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Antje Grosche
- Department of Physiological Genomics, BioMedical Center, Ludwig-Maximilian University Munich, 82152 Planegg-Martinsried, Germany
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
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14
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Chen N, Lee H, Kim AH, Liu PK, Kang EYC, Tseng YJ, Seo GH, Khang R, Liu L, Chen KJ, Wu WC, Hsiao MC, Wang NK. Case report: novel PCDH15 variant causes usher syndrome type 1F with congenital hearing loss and syndromic retinitis pigmentosa. BMC Ophthalmol 2022; 22:441. [PMID: 36384460 PMCID: PMC9670441 DOI: 10.1186/s12886-022-02659-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/29/2022] [Indexed: 11/17/2022] Open
Abstract
Abstract
Background
Usher syndrome (USH) is an autosomal recessive disorder primarily responsible for deaf-blindness. Patients with subtype Usher syndrome type 1 (USH1) typically experience congenital sensorineural hearing loss, abnormal vestibular function, and retinitis pigmentosa (RP). Here we present a case of Usher syndrome type 1F (USH1F) with a novel homozygous variant in the calcium-dependent cell-cell adhesion protocadherin-15 (PCDH15) gene.
Case presentation
Ophthalmic examinations were evaluated over a course of 10 years and the disease-causing variant was identified by whole exome sequencing (WES). Initial and follow-up examination of color fundus photos after 10 years revealed an increase in bone spicule pigment deposits in both eyes. A parafoveal hyper-AF ring in both eyes was shown in fundus autofluorescence (FAF) with a progressive diameter-wise constriction observed over 8 years. Outer nuclear layer (ONL) loss was observed in parafoveal and perifoveal regions of both eyes on spectral domain–optical coherence tomography (SD-OCT). Full-field electroretinography (ffERG) showed extinguished global retinal function. WES identified a novel two-base-pair deletion, c.60_61del (p.Phe21Ter), in the PCDH15 gene, confirming the diagnosis of USH1F.
Conclusions
We report a novel homozygous PCDH15 pathogenic variant expected to lead to nonsense-mediated decay (NMD) of PCDH15 mRNA. The patient exhibits a loss of function with USH1F, experiencing congenital hearing loss and syndromic RP.
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15
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Leong YC, Di Foggia V, Pramod H, Bitner-Glindzicz M, Patel A, Sowden JC. Molecular pathology of Usher 1B patient-derived retinal organoids at single cell resolution. Stem Cell Reports 2022; 17:2421-2437. [DOI: 10.1016/j.stemcr.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 11/08/2022] Open
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16
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Zebrafish and inherited photoreceptor disease: Models and insights. Prog Retin Eye Res 2022; 91:101096. [PMID: 35811244 DOI: 10.1016/j.preteyeres.2022.101096] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 11/21/2022]
Abstract
Photoreceptor dysfunctions and degenerative diseases are significant causes of vision loss in patients, with few effective treatments available. Targeted interventions to prevent or reverse photoreceptor-related vision loss are not possible without a thorough understanding of the underlying mechanism leading to disease, which is exceedingly difficult to accomplish in the human system. Cone diseases are particularly challenging to model, as some popular genetically modifiable model animals are nocturnal with a rod-dominant visual system and cones that have dissimilarities to human cones. As a result, cone diseases, which affect visual acuity, colour perception, and central vision in patients, are generally poorly understood in terms of pathology and mechanism. Zebrafish (Danio rerio) provide the opportunity to model photoreceptor diseases in a diurnal vertebrate with a cone-rich retina which develops many macular degeneration-like pathologies. Zebrafish undergo external development, allowing early-onset retinal diseases to be detected and studied, and many ophthalmic tools are available for zebrafish visual assessment during development and adulthood. There are numerous zebrafish models of photoreceptor disease, spanning the various types of photoreceptor disease (developmental, rod, cone, and mixed photoreceptor diseases) and genetic/molecular cause. In this review, we explore the features of zebrafish that make them uniquely poised to model cone diseases, summarize the established zebrafish models of inherited photoreceptor disease, and discuss how disease in these models compares to the human presentation, where applicable. Further, we highlight the contributions of these zebrafish models to our understanding of photoreceptor biology and disease, and discuss future directions for utilising and investigating these diverse models.
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17
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The genetic and phenotypic landscapes of Usher syndrome: from disease mechanisms to a new classification. Hum Genet 2022; 141:709-735. [PMID: 35353227 PMCID: PMC9034986 DOI: 10.1007/s00439-022-02448-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/04/2022] [Indexed: 12/16/2022]
Abstract
Usher syndrome (USH) is the most common cause of deaf–blindness in humans, with a prevalence of about 1/10,000 (~ 400,000 people worldwide). Cochlear implants are currently used to reduce the burden of hearing loss in severe-to-profoundly deaf patients, but many promising treatments including gene, cell, and drug therapies to restore the native function of the inner ear and retinal sensory cells are under investigation. The traditional clinical classification of Usher syndrome defines three major subtypes—USH1, 2 and 3—according to hearing loss severity and onset, the presence or absence of vestibular dysfunction, and age at onset of retinitis pigmentosa. Pathogenic variants of nine USH genes have been initially reported: MYO7A, USH1C, PCDH15, CDH23, and USH1G for USH1, USH2A, ADGRV1, and WHRN for USH2, and CLRN1 for USH3. Based on the co-occurrence of hearing and vision deficits, the list of USH genes has been extended to few other genes, but with limited supporting information. A consensus on combined criteria for Usher syndrome is crucial for the development of accurate diagnosis and to improve patient management. In recent years, a wealth of information has been obtained concerning the properties of the Usher proteins, related molecular networks, potential genotype–phenotype correlations, and the pathogenic mechanisms underlying the impairment or loss of hearing, balance and vision. The advent of precision medicine calls for a clear and more precise diagnosis of Usher syndrome, exploiting all the existing data to develop a combined clinical/genetic/network/functional classification for Usher syndrome.
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18
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Grotz S, Schäfer J, Wunderlich KA, Ellederova Z, Auch H, Bähr A, Runa-Vochozkova P, Fadl J, Arnold V, Ardan T, Veith M, Santamaria G, Dhom G, Hitzl W, Kessler B, Eckardt C, Klein J, Brymova A, Linnert J, Kurome M, Zakharchenko V, Fischer A, Blutke A, Döring A, Suchankova S, Popelar J, Rodríguez-Bocanegra E, Dlugaiczyk J, Straka H, May-Simera H, Wang W, Laugwitz KL, Vandenberghe LH, Wolf E, Nagel-Wolfrum K, Peters T, Motlik J, Fischer MD, Wolfrum U, Klymiuk N. Early disruption of photoreceptor cell architecture and loss of vision in a humanized pig model of usher syndromes. EMBO Mol Med 2022; 14:e14817. [PMID: 35254721 PMCID: PMC8988205 DOI: 10.15252/emmm.202114817] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 02/04/2022] [Accepted: 02/09/2022] [Indexed: 01/17/2023] Open
Abstract
Usher syndrome (USH) is the most common form of monogenic deaf-blindness. Loss of vision is untreatable and there are no suitable animal models for testing therapeutic strategies of the ocular constituent of USH, so far. By introducing a human mutation into the harmonin-encoding USH1C gene in pigs, we generated the first translational animal model for USH type 1 with characteristic hearing defect, vestibular dysfunction, and visual impairment. Changes in photoreceptor architecture, quantitative motion analysis, and electroretinography were characteristics of the reduced retinal virtue in USH1C pigs. Fibroblasts from USH1C pigs or USH1C patients showed significantly elongated primary cilia, confirming USH as a true and general ciliopathy. Primary cells also proved their capacity for assessing the therapeutic potential of CRISPR/Cas-mediated gene repair or gene therapy in vitro. AAV-based delivery of harmonin into the eye of USH1C pigs indicated therapeutic efficacy in vivo.
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Affiliation(s)
- Sophia Grotz
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Jessica Schäfer
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Kirsten A Wunderlich
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Zdenka Ellederova
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Hannah Auch
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Andrea Bähr
- Center for Innovative Medical Models, LMU Munich, Munich, Germany.,Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Petra Runa-Vochozkova
- Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Janet Fadl
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Vanessa Arnold
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Taras Ardan
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Miroslav Veith
- Ophthalmology Clinic, University Hospital Kralovske Vinohrady, Praha, Czech Republic
| | - Gianluca Santamaria
- Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Georg Dhom
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Wolfgang Hitzl
- Biostatistics and Data Science, Paracelsus Medical University, Salzburg, Austria
| | - Barbara Kessler
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Christian Eckardt
- Center for Innovative Medical Models, LMU Munich, Munich, Germany.,Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Joshua Klein
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Anna Brymova
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - Joshua Linnert
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Mayuko Kurome
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Valeri Zakharchenko
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Andrea Fischer
- Veterinary Faculty, Small Animal Clinics, LMU Munich, Munich, Germany
| | - Andreas Blutke
- Institute of Experimental Genetics, Helmholtz Center Munich, Neuherberg, Germany
| | - Anna Döring
- Veterinary Faculty, Small Animal Clinics, LMU Munich, Munich, Germany
| | - Stepanka Suchankova
- Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Jiri Popelar
- Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic
| | - Eduardo Rodríguez-Bocanegra
- Centre for Ophthalmology, University Eye Hospital, University Hospital Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Julia Dlugaiczyk
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich (USZ), University of Zurich, Zurich, Switzerland
| | - Hans Straka
- Faculty of Biology, LMU Munich, Planegg, Germany
| | - Helen May-Simera
- Institute of Molecular Physiology, Cilia Biology, JGU Mainz, Mainz, Germany
| | - Weiwei Wang
- Grousbeck Gene Therapy Center, Mass Eye and Ear and Harvard Medical School, Boston, MA, USA
| | - Karl-Ludwig Laugwitz
- Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
| | - Luk H Vandenberghe
- Grousbeck Gene Therapy Center, Mass Eye and Ear and Harvard Medical School, Boston, MA, USA
| | - Eckhard Wolf
- Chair of Molecular Animal Breeding and Biotechnology, LMU Munich, Munich, Germany.,Center for Innovative Medical Models, LMU Munich, Munich, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany.,Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Tobias Peters
- Centre for Ophthalmology, University Eye Hospital, University Hospital Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
| | - Jan Motlik
- Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov, Czech Republic
| | - M Dominik Fischer
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford, UK.,Nuffield Laboratory of Ophthalmology, NDCN, University of Oxford, Oxford, UK
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg University (JGU), Mainz, Germany
| | - Nikolai Klymiuk
- Center for Innovative Medical Models, LMU Munich, Munich, Germany.,Large Animal Models in Cardiovascular Research, Internal Medical Department I, TU Munich, Munich, Germany
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19
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Planar polarity in primate cone photoreceptors: a potential role in Stiles Crawford effect phototropism. Commun Biol 2022; 5:89. [PMID: 35075261 PMCID: PMC8786850 DOI: 10.1038/s42003-021-02998-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 12/15/2021] [Indexed: 11/18/2022] Open
Abstract
Human cone phototropism is a key mechanism underlying the Stiles-Crawford effect, a psychophysiological phenomenon according to which photoreceptor outer/inner segments are aligned along with the direction of incoming light. However, such photomechanical movements of photoreceptors remain elusive in mammals. We first show here that primate cone photoreceptors have a planar polarity organized radially around the optical center of the eye. This planar polarity, based on the structure of the cilium and calyceal processes, is highly reminiscent of the planar polarity of the hair cells and their kinocilium and stereocilia. Secondly, we observe under super-high resolution expansion microscopy the cytoskeleton and Usher proteins architecture in the photoreceptors, which appears to establish a mechanical continuity between the outer and inner segments. Taken together, these results suggest a comprehensive cellular mechanism consistent with an active phototropism of cones toward the optical center of the eye, and thus with the Stiles-Crawford effect. Verschueren et al. expand our understanding of the Stiles-Crawford effect in mammals by using super-high resolution expansion microscopy of the adult macaque eye. They show that cone photoreceptors have a planar polarity organized radially around the optical center of the eye and that Usher proteins establish a mechanical continuity between the outer and inner segments, which sheds light on the Stiles-Crawford effect in this species.
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20
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Yusuf IH, Garrett A, MacLaren RE, Issa PC. Retinal cadherins and the retinal cadherinopathies: Current concepts and future directions. Prog Retin Eye Res 2022; 90:101038. [DOI: 10.1016/j.preteyeres.2021.101038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 12/13/2021] [Accepted: 12/20/2021] [Indexed: 12/18/2022]
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21
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Miles A, Blair C, Emili A, Tropepe V. Usher syndrome type 1-associated gene, pcdh15b, is required for photoreceptor structural integrity in zebrafish. Dis Model Mech 2021; 14:272551. [PMID: 34668518 PMCID: PMC8669488 DOI: 10.1242/dmm.048965] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 10/13/2021] [Indexed: 12/23/2022] Open
Abstract
Blindness associated with Usher syndrome type 1 (USH1) is typically characterized as rod photoreceptor degeneration, followed by secondary loss of cones. The mechanisms leading to blindness are unknown because most genetic mouse models only recapitulate auditory defects. We generated zebrafish mutants for one of the USH1 genes, protocadherin-15b (pcdh15b), a putative cell adhesion molecule. Zebrafish Pcdh15 is expressed exclusively in photoreceptors within calyceal processes (CPs), at the base of the outer segment (OS) and within the synapse. In our mutants, rod and cone photoreceptor integrity is compromised, with early and progressively worsening abnormal OS disc growth and detachment, in part due to weakening CP contacts. These effects were attenuated or exacerbated by growth in dark and bright-light conditions, respectively. We also describe novel evidence for structural defects in synapses of pcdh15b mutant photoreceptors. Cell death does not accompany these defects at early stages, suggesting that photoreceptor structural defects, rather than overt cell loss, may underlie vision deficits. Thus, we present the first genetic animal model of a PCDH15-associated retinopathy that can be used to understand the aetiology of blindness in USH1. This article has an associated First Person interview with the first author of the paper. Summary: We present one of the first genetic animal mutants for PCDH15 that displays a severe, early retinopathy and suggests that zebrafish could be a useful model for PCDH15-associated retinal phenotypes.
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Affiliation(s)
- Amanda Miles
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Clarke Blair
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Andrew Emili
- Center for Network Systems Biology, Boston University, Boston, MA 02118, USA
| | - Vincent Tropepe
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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22
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Sethna S, Zein WM, Riaz S, Giese AP, Schultz JM, Duncan T, Hufnagel RB, Brewer CC, Griffith AJ, Redmond TM, Riazuddin S, Friedman TB, Ahmed ZM. Proposed therapy, developed in a Pcdh15-deficient mouse, for progressive loss of vision in human Usher syndrome. eLife 2021; 10:67361. [PMID: 34751129 PMCID: PMC8577840 DOI: 10.7554/elife.67361] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 10/20/2021] [Indexed: 12/15/2022] Open
Abstract
Usher syndrome type I (USH1) is characterized by deafness, vestibular areflexia, and progressive retinal degeneration. The protein-truncating p.Arg245* founder variant of PCDH15 (USH1F) has an ~2% carrier frequency amongst Ashkenazi Jews accounts for ~60% of their USH1 cases. Here, longitudinal phenotyping in 13 USH1F individuals revealed progressive retinal degeneration, leading to severe vision loss with macular atrophy by the sixth decade. Half of the affected individuals were legally blind by their mid-50s. The mouse Pcdh15R250X variant is equivalent to human p.Arg245*. Homozygous Pcdh15R250X mice also have visual deficits and aberrant light-dependent translocation of the phototransduction cascade proteins, arrestin, and transducin. Retinal pigment epithelium (RPE)-specific retinoid cycle proteins, RPE65 and CRALBP, were also reduced in Pcdh15R250X mice, indicating a dual role for protocadherin-15 in photoreceptors and RPE. Exogenous 9-cis retinal improved ERG amplitudes in Pcdh15R250X mice, suggesting a basis for a clinical trial of FDA-approved retinoids to preserve vision in USH1F patients.
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Affiliation(s)
- Saumil Sethna
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Sehar Riaz
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States.,National Center of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Arnaud Pj Giese
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States
| | - Julie M Schultz
- Laboratory of Molecular Genetics, National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Todd Duncan
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Carmen C Brewer
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, Bethesda, United States
| | - Andrew J Griffith
- Otolaryngology Branch, National Institute of Deafness and Other Communication Disorders, Bethesda, United States
| | - T Michael Redmond
- Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Saima Riazuddin
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute of Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, United States
| | - Zubair M Ahmed
- Department of Otorhinolaryngology - Head & Neck Surgery, University of Maryland School of Medicine, Baltimore, United States.,Departments of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, United States.,Departments of Molecular Biology and Biochemistry, University of Maryland School of Medicine, Baltimore, United States
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23
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Dinculescu A, Link BA, Saperstein DA. Retinal Gene Therapy for Usher Syndrome: Current Developments, Challenges, and Perspectives. Int Ophthalmol Clin 2021; 61:109-124. [PMID: 34584048 PMCID: PMC8478317 DOI: 10.1097/iio.0000000000000378] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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24
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Zhao Q, Shen Y, Li X, Tian F, Yu X, Yobas L, Park H, Duan Y, Huang P. Analyzing protein-protein interactions in rare cells using microbead-based single-molecule pulldown assay. LAB ON A CHIP 2021; 21:3137-3149. [PMID: 34165117 DOI: 10.1039/d1lc00260k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
For studying protein-protein interactions (PPIs) in general, a powerful and commonly used technique is conventional coimmunoprecipitation (co-IP/pulldown) followed by western blotting. However, the technique does not provide precise information regarding the kinetics and stoichiometry of PPIs. Another drawback is that the sensitivity of conventional co-IP is not suitable for examining PPIs in rare cells such as sensory hair cells, circulating tumor cells, embryonic stem cells, and subsets of immune cells. The current single-molecule pulldown (SiMPull) assay can potentially be used for studying PPIs in rare cells but its wide application is hindered by the high technical barrier and time consumption. We report an innovative, agarose microbead-based approach for SiMPull. We used commercially available, pre-surface-functionalized agarose microbeads to capture the protein of interest together with its binding partners specifically from cell extracts and observed these interactions under a microscope at the single-molecule level. Relative to the original method, microbead-based SiMPull is considerably faster, easier to use, and more reproducible and yet provides similar sensitivity and signal-to-background ratio; specifically, with the new method, sample-preparation time is substantially decreased (from ∼10 to ∼3 h). These crucial features should facilitate wide application of the powerful and versatile SiMPull method in common biological and clinical laboratories. Notably, by exploiting the simplicity and ultrahigh sensitivity of microbead-based SiMPull, we used the method in the study of rare auditory hair cells and γδ T cells for the first time.
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Affiliation(s)
- Qirui Zhao
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
| | - Yusheng Shen
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiaofen Li
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Fang Tian
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiaojie Yu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.
| | - Levent Yobas
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China and Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Hyokeun Park
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China. and Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yuanyuan Duan
- Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Pingbo Huang
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China. and Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China and HKUST Shenzhen Research Institute, Hong Kong University of Science and Technology, Hong Kong, China and Hong Kong Branch of Guangdong Southern Marine Science and Engineering Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong, China
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25
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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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26
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Garcia-Delgado AB, Valdes-Sanchez L, Morillo-Sanchez MJ, Ponte-Zuñiga B, Diaz-Corrales FJ, de la Cerda B. Dissecting the role of EYS in retinal degeneration: clinical and molecular aspects and its implications for future therapy. Orphanet J Rare Dis 2021; 16:222. [PMID: 34001227 PMCID: PMC8127272 DOI: 10.1186/s13023-021-01843-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/23/2021] [Indexed: 01/22/2023] Open
Abstract
Mutations in the EYS gene are one of the major causes of autosomal recessive retinitis pigmentosa. EYS-retinopathy presents a severe clinical phenotype, and patients currently have no therapeutic options. The progress in personalised medicine and gene and cell therapies hold promise for treating this degenerative disease. However, lack of understanding and incomplete comprehension of disease's mechanism and the role of EYS in the healthy retina are critical limitations for the translation of current technical advances into real therapeutic possibilities. This review recapitulates the present knowledge about EYS-retinopathies, their clinical presentations and proposed genotype–phenotype correlations. Molecular details of the gene and the protein, mainly based on animal model data, are analysed. The proposed cellular localisation and roles of this large multi-domain protein are detailed. Future therapeutic approaches for EYS-retinopathies are discussed.
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Affiliation(s)
- Ana B Garcia-Delgado
- Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Avda. Americo Vespucio 24, 41092, Seville, Spain
| | - Lourdes Valdes-Sanchez
- Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Avda. Americo Vespucio 24, 41092, Seville, Spain
| | | | - Beatriz Ponte-Zuñiga
- Department of Ophthalmology, University Hospital Virgen Macarena, Seville, Spain.,Retics Oftared, Institute of Health Carlos III, Madrid, Spain
| | - Francisco J Diaz-Corrales
- Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Avda. Americo Vespucio 24, 41092, Seville, Spain.
| | - Berta de la Cerda
- Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER), Avda. Americo Vespucio 24, 41092, Seville, Spain
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27
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Lewis TR, Makia MS, Castillo CM, Al-Ubaidi MR, Naash MI, Arshavsky VY. Photoreceptor Disc Enclosure Is Tightly Controlled by Peripherin-2 Oligomerization. J Neurosci 2021; 41:3588-3596. [PMID: 33707293 PMCID: PMC8055076 DOI: 10.1523/jneurosci.0041-21.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/15/2021] [Accepted: 03/05/2021] [Indexed: 11/21/2022] Open
Abstract
Mutations in the PRPH2 gene encoding the photoreceptor-specific protein PRPH2 (also known as peripherin-2 or rds) cause a broad range of autosomal dominant retinal diseases. Most of these mutations affect the structure of the light-sensitive photoreceptor outer segment, which is composed of a stack of flattened "disc" membranes surrounded by the plasma membrane. The outer segment is renewed on a daily basis in a process whereby new discs are added at the outer segment base and old discs are shed at the outer segment tip. New discs are formed as serial membrane evaginations, which eventually enclose through a complex process of membrane remodeling (completely in rods and partially in cones). As disc enclosure proceeds, PRPH2 localizes to the rims of enclosed discs where it forms oligomers which fortify the highly curved membrane structure of these rims. In this study, we analyzed the outer segment phenotypes of mice of both sexes bearing a single copy of either the C150S or the Y141C PRPH2 mutation known to prevent or increase the degree of PRPH2 oligomerization, respectively. Strikingly, both mutations increased the number of newly forming, not-yet-enclosed discs, indicating that the precision of disc enclosure is regulated by PRPH2 oligomerization. Without tightly controlled enclosure, discs occasionally over-elongate and form large membranous "whorls" instead of disc stacks. These data show that the defects in outer segment structure arising from abnormal PRPH2 oligomerization are manifested at the stage of disc enclosure.SIGNIFICANCE STATEMENT The light-sensitive photoreceptor outer segment contains a stack of flattened "disc" membranes that are surrounded, or "enclosed," by the outer segment membrane. Disc enclosure is an adaptation increasing photoreceptor light sensitivity by facilitating the diffusion of the second messenger along the outer segment axes. However, the molecular mechanisms by which photoreceptor discs enclose within the outer segment membrane remain poorly understood. We now demonstrate that oligomers of the photoreceptor-specific protein peripherin-2, or PRPH2, play an active role in this process. We further propose that defects in disc enclosure because of abnormal PRPH2 oligomerization result in major structural abnormalities of the outer segment, ultimately leading to loss of visual function and cell degeneration in PRPH2 mutant models and human patients.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
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28
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Functional compartmentalization of photoreceptor neurons. Pflugers Arch 2021; 473:1493-1516. [PMID: 33880652 DOI: 10.1007/s00424-021-02558-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 12/16/2022]
Abstract
Retinal photoreceptors are neurons that convert dynamically changing patterns of light into electrical signals that are processed by retinal interneurons and ultimately transmitted to vision centers in the brain. They represent the essential first step in seeing without which the remainder of the visual system is rendered moot. To support this role, the major functions of photoreceptors are segregated into three main specialized compartments-the outer segment, the inner segment, and the pre-synaptic terminal. This compartmentalization is crucial for photoreceptor function-disruption leads to devastating blinding diseases for which therapies remain elusive. In this review, we examine the current understanding of the molecular and physical mechanisms underlying photoreceptor functional compartmentalization and highlight areas where significant knowledge gaps remain.
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29
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Colcombet-Cazenave B, Druart K, Bonnet C, Petit C, Spérandio O, Guglielmini J, Wolff N. Phylogenetic analysis of Harmonin homology domains. BMC Bioinformatics 2021; 22:190. [PMID: 33853521 PMCID: PMC8048344 DOI: 10.1186/s12859-021-04116-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/24/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Harmonin Homogy Domains (HHD) are recently identified orphan domains of about 70 residues folded in a compact five alpha-helix bundle that proved to be versatile in terms of function, allowing for direct binding to a partner as well as regulating the affinity and specificity of adjacent domains for their own targets. Adding their small size and rather simple fold, HHDs appear as convenient modules to regulate protein-protein interactions in various biological contexts. Surprisingly, only nine HHDs have been detected in six proteins, mainly expressed in sensory neurons. RESULTS Here, we built a profile Hidden Markov Model to screen the entire UniProtKB for new HHD-containing proteins. Every hit was manually annotated, using a clustering approach, confirming that only a few proteins contain HHDs. We report the phylogenetic coverage of each protein and build a phylogenetic tree to trace the evolution of HHDs. We suggest that a HHD ancestor is shared with Paired Amphipathic Helices (PAH) domains, a four-helix bundle partially sharing fold and functional properties. We characterized amino-acid sequences of the various HHDs using pairwise BLASTP scoring coupled with community clustering and manually assessed sequence features among each individual family. These sequence features were analyzed using reported structures as well as homology models to highlight structural motifs underlying HHDs fold. We show that functional divergence is carried out by subtle differences in sequences that automatized approaches failed to detect. CONCLUSIONS We provide the first HHD databases, including sequences and conservation, phylogenic trees and a list of HHD variants found in the auditory system, which are available for the community. This case study highlights surprising phylogenetic properties found in orphan domains and will assist further studies of HHDs. We unveil the implication of HHDs in their various binding interfaces using conservation across families and a new protein-protein surface predictor. Finally, we discussed the functional consequences of three identified pathogenic HHD variants involved in Hoyeraal-Hreidarsson syndrome and of three newly reported pathogenic variants identified in patients suffering from Usher Syndrome.
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Affiliation(s)
- Baptiste Colcombet-Cazenave
- Unité Récepteurs-Canaux, Institut Pasteur, 75015, Paris, France
- Collège Doctoral, Sorbonne Université, 75005, Paris, France
| | - Karen Druart
- Unité de Bio-Informatique Structurale, Institut Pasteur, 75015, Paris, France
| | - Crystel Bonnet
- Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, 75015, Paris, France
- INSERM, Institut de l'Audition, Institut Pasteur, 75012, Paris, France
| | - Christine Petit
- Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, 75015, Paris, France
- INSERM, Institut de l'Audition, Institut Pasteur, 75012, Paris, France
| | - Olivier Spérandio
- Unité de Bio-Informatique Structurale, Institut Pasteur, 75015, Paris, France
| | - Julien Guglielmini
- Hub de Bioinformatique et Biostatistique - Département Biologie Computationnelle, USR 3756 CNRS, Institut Pasteur, Paris, France
| | - Nicolas Wolff
- Unité Récepteurs-Canaux, Institut Pasteur, 75015, Paris, France.
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30
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Cirilo JA, Gunther LK, Yengo CM. Functional Role of Class III Myosins in Hair Cells. Front Cell Dev Biol 2021; 9:643856. [PMID: 33718386 PMCID: PMC7947357 DOI: 10.3389/fcell.2021.643856] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/01/2021] [Indexed: 11/14/2022] Open
Abstract
Cytoskeletal motors produce force and motion using the energy from ATP hydrolysis and function in a variety of mechanical roles in cells including muscle contraction, cargo transport, and cell division. Actin-based myosin motors have been shown to play crucial roles in the development and function of the stereocilia of auditory and vestibular inner ear hair cells. Hair cells can contain hundreds of stereocilia, which rely on myosin motors to elongate, organize, and stabilize their structure. Mutations in many stereocilia-associated myosins have been shown to cause hearing loss in both humans and animal models suggesting that each myosin isoform has a specific function in these unique parallel actin bundle-based protrusions. Here we review what is known about the classes of myosins that function in the stereocilia, with a special focus on class III myosins that harbor point mutations associated with delayed onset hearing loss. Much has been learned about the role of the two class III myosin isoforms, MYO3A and MYO3B, in maintaining the precise stereocilia lengths required for normal hearing. We propose a model for how class III myosins play a key role in regulating stereocilia lengths and demonstrate how their motor and regulatory properties are particularly well suited for this function. We conclude that ongoing studies on class III myosins and other stereocilia-associated myosins are extremely important and may lead to novel therapeutic strategies for the treatment of hearing loss due to stereocilia degeneration.
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Affiliation(s)
- Joseph A Cirilo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States
| | - Laura K Gunther
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, College of Medicine, Pennsylvania State University, Hershey, PA, United States
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31
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Toualbi L, Toms M, Moosajee M. USH2A-retinopathy: From genetics to therapeutics. Exp Eye Res 2020; 201:108330. [PMID: 33121974 PMCID: PMC8417766 DOI: 10.1016/j.exer.2020.108330] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 01/21/2023]
Abstract
Bilallelic variants in the USH2A gene can cause Usher syndrome type 2 and non-syndromic retinitis pigmentosa. In both disorders, the retinal phenotype involves progressive rod photoreceptor loss resulting in nyctalopia and a constricted visual field, followed by subsequent cone degeneration, leading to the loss of central vision and severe visual impairment. The USH2A gene raises many challenges for researchers and clinicians due to a broad spectrum of mutations, a large gene size hampering gene therapy development and limited knowledge on its pathogenicity. Patients with Usher type 2 may benefit from hearing aids or cochlear implants to correct their hearing defects, but there are currently no approved treatments available for the USH2A-retinopathy. Several treatment strategies, including antisense oligonucleotides and translational readthrough inducing drugs, have shown therapeutic promise in preclinical studies. Further understanding of the pathogenesis and natural history of USH2A-related disorders is required to develop innovative treatments and design clinical trials based on reliable outcome measures. The present review will discuss the current knowledge about USH2A, the emerging therapeutics and existing challenges.
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Affiliation(s)
- Lyes Toualbi
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Maria Toms
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London, EC1V 9EL, UK; Ocular Genomics and Therapeutics Laboratory, The Francis Crick Institute, London, NW1 1AT, UK; Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK; Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK.
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Bolz HJ. Usher syndrome: diagnostic approach, differential diagnoses and proposal of an updated function-based genetic classification. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
Usher syndrome (USH) manifests with congenital and apparently isolated hearing loss, followed by retinal degeneration in later life. Therefore, and because of its high prevalence in the congenitally hearing-impaired population, USH is one of the most relevant deafness syndromes. Next-generation sequencing (NGS)-based testing can now provide most analyzed USH patients with a molecular diagnosis, based on mutations in 11 genes. Given the availability of several excellent articles on the clinical and biochemical basis of USH, this short review focuses on critical assessment of new genes announced as USH genes, clinical and genetic differential diagnoses and therapeutic developments. Because obsolete loci, disproved USH genes and the inclusion of genes whose mutations cause similar phenotypes have increasingly blurred genetic classification, a revision based on phenotype restricted to genes related to the Usher protein complex is proposed.
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Affiliation(s)
- Hanno J. Bolz
- Senckenberg Centre for Human Genetics , Weismüllerstr. 50 , Frankfurt am Main , Germany
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Zheng C, Ren X, Xing D, Bu S, Wen D, He Y, Zhang J, Dong L, Li X. A novel missense mutation locus of cadherin 23 and the interaction of cadherin 23 and protocadherin 15 in a patient with usher syndrome. Ophthalmic Genet 2020; 41:501-504. [PMID: 32835555 DOI: 10.1080/13816810.2020.1768554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Chuanzhen Zheng
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Xinjun Ren
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Dongjun Xing
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Shaochong Bu
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Dejia Wen
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Ye He
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Jinping Zhang
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Lijie Dong
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
| | - Xiaorong Li
- Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin International Joint Research and Development Centre of Ophthalmology and Vision Science, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital , Tianjin, China
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French LS, Mellough CB, Chen FK, Carvalho LS. A Review of Gene, Drug and Cell-Based Therapies for Usher Syndrome. Front Cell Neurosci 2020; 14:183. [PMID: 32733204 PMCID: PMC7363968 DOI: 10.3389/fncel.2020.00183] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022] Open
Abstract
Usher syndrome is a genetic disorder causing neurosensory hearing loss and blindness from retinitis pigmentosa (RP). Adaptive techniques such as braille, digital and optical magnifiers, mobility training, cochlear implants, or other assistive listening devices are indispensable for reducing disability. However, there is currently no treatment to reduce or arrest sensory cell degeneration. There are several classes of treatments for Usher syndrome being investigated. The present article reviews the progress this research has made towards delivering commercial options for patients with Usher syndrome.
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Affiliation(s)
- Lucy S French
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia
| | - Carla B Mellough
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, WA, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, WA, Australia
| | - Livia S Carvalho
- Centre for Ophthalmology and Visual Sciences (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia
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Choi MS, Graves MJ, Matoo S, Storad ZA, El Sheikh Idris RA, Weck ML, Smith ZB, Tyska MJ, Crawley SW. The small EF-hand protein CALML4 functions as a critical myosin light chain within the intermicrovillar adhesion complex. J Biol Chem 2020; 295:9281-9296. [PMID: 32209652 DOI: 10.1074/jbc.ra120.012820] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 03/18/2020] [Indexed: 11/06/2022] Open
Abstract
Specialized transporting and sensory epithelial cells employ homologous protocadherin-based adhesion complexes to remodel their apical membrane protrusions into organized functional arrays. Within the intestine, the nutrient-transporting enterocytes utilize the intermicrovillar adhesion complex (IMAC) to assemble their apical microvilli into an ordered brush border. The IMAC bears remarkable homology to the Usher complex, whose disruption results in the sensory disorder type 1 Usher syndrome (USH1). However, the entire complement of proteins that comprise both the IMAC and Usher complex are not yet fully elucidated. Using a protein isolation strategy to recover the IMAC, we have identified the small EF-hand protein calmodulin-like protein 4 (CALML4) as an IMAC component. Consistent with this finding, we show that CALML4 exhibits marked enrichment at the distal tips of enterocyte microvilli, the site of IMAC function, and is a direct binding partner of the IMAC component myosin-7b. Moreover, distal tip enrichment of CALML4 is strictly dependent upon its association with myosin-7b, with CALML4 acting as a light chain for this myosin. We further show that genetic disruption of CALML4 within enterocytes results in brush border assembly defects that mirror the loss of other IMAC components and that CALML4 can also associate with the Usher complex component myosin-7a. Our study further defines the molecular composition and protein-protein interaction network of the IMAC and Usher complex and may also shed light on the etiology of the sensory disorder USH1H.
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Affiliation(s)
- Myoung Soo Choi
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Maura J Graves
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Samaneh Matoo
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | - Zachary A Storad
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
| | | | - Meredith L Weck
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37240
| | - Zachary B Smith
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37240
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37240
| | - Scott W Crawley
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606
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Géléoc GGS, El-Amraoui A. Disease mechanisms and gene therapy for Usher syndrome. Hear Res 2020; 394:107932. [PMID: 32199721 DOI: 10.1016/j.heares.2020.107932] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/03/2020] [Accepted: 02/26/2020] [Indexed: 12/11/2022]
Abstract
Usher syndrome (USH) is a major cause of deaf-blindness in humans, affecting ∼400 000 patients worldwide. Three clinical subtypes, USH1-3, have been defined, with 10 USH genes identified so far. In recent years, in addition to identification of new Usher genes and diagnostic tools, major progress has been made in understanding the role of Usher proteins and how they cooperate through interaction networks to ensure proper development, architecture and function of the stereociliary bundle at the apex of sensory hair cells in the inner ear. Several Usher mouse models of known human Usher genes have been characterized. These mice faithfully reproduce the auditory phenotype associated with Usher syndrome and the vestibular phenotype associated with some mutations in USH genes, particularly USH1. Interestingly, very few mouse models of Usher syndrome recapitulate the retinal phenotype associated with the disease in human. Usher patients can benefit from hearing aids or cochlear implants, which partially alleviate auditory sensory deprivation. However, there are currently no biological treatments available for auditory or visual dysfunction in Usher patients. Development of novel therapies for Usher syndrome has sprouted over the past decade, building on recent progress in gene transfer and new gene editing tools. Promising success demonstrating recovery of hearing and balance functions have been obtained via distinct therapeutic strategies in animal models. Clinical translation to Usher patients, however, calls for further improvements and concerted efforts to overcome the challenges ahead.
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Affiliation(s)
- Gwenaelle G S Géléoc
- Boston Children's Hospital and Harvard Medical School, 3, Blackfan circle, Center for Life Science, 03001, Boston, MA, 02115, United States.
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Institut Pasteur, INSERM-UMRS1120, Sorbonne Université, 25 rue du Dr. Roux, 75015, Paris, France.
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Menghini M, Cehajic-Kapetanovic J, Yusuf IH, MacLaren RE. A novel splice-site variant in CDH23 in a patient with Usher syndrome type 1. Ophthalmic Genet 2019; 40:545-548. [PMID: 31755791 DOI: 10.1080/13816810.2019.1692359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background: Gene editing has shown huge potential in correcting aberrant splicing and Cas13 has been identified as being particularly suitable for targeting RNA. It has therefore become increasingly important to highlight new splice site mutations that may be correctable, particularly in genes that are too large to be encoded by AAV vectors. About 20% of Usher Type 1 cases are caused by mutations in CDH23.Purpose: To report a novel splice site mutation of CDH23 associated with Usher Type 1D.Materials and Methods: Case report.Results: A 35-year-old Caucasian female who is congenitally deaf with vestibular dysfunction presented with visual acuity of 6/12 in both eyes. Fundus examination revealed findings typical of retinitis pigmentosa with foveal preservation of photoreceptor layer. Next generation sequencing analysis revealed a novel homozygous variant, c.9319 + 1G>T in CDH23 consistent with the diagnosis of Usher Syndrome Type 1D. The c.9319 + 1G>T variant is predicted to affect splicing at the exon 65/intron 65 boundary, which highly likely leads to complete skipping of exon 65.Conclusions: We describe a case of a typical Usher Syndrome Type 1D caused by a novel splice site variant in CDH23. Currently there are no treatments for CDH23 related retinal degeneration, partly because the cDNA size of 10kb is too large for AAV vector gene augmentation therapy. Alternative strategies include CRISPR-Cas9 adenine base editors and RNA editing with CRISPR-Cas13. Single-nucleotide editing represents a promising approach for targeting this variant in CDH23 to restore the wildtype splice donor site at this position.
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Affiliation(s)
- Moreno Menghini
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Imran H Yusuf
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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38
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Stingl K, Kurtenbach A, Hahn G, Kernstock C, Hipp S, Zobor D, Kohl S, Bonnet C, Mohand-Saïd S, Audo I, Fakin A, Hawlina M, Testa F, Simonelli F, Petit C, Sahel JA, Zrenner E. Full-field electroretinography, visual acuity and visual fields in Usher syndrome: a multicentre European study. Doc Ophthalmol 2019; 139:151-160. [PMID: 31267413 DOI: 10.1007/s10633-019-09704-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/19/2019] [Indexed: 01/30/2023]
Abstract
PURPOSE Usher syndrome (USH) is a multisensory deficiency involving vision, hearing and the vestibular system. The purpose of this study is to report on the functional data (i.e. electroretinography, visual fields, visual acuity) of patients with retinitis pigmentosa (RP) due to Usher syndrome that were collected in a multicentre European study (TREATRUSH). METHODS A total of 268 genetically confirmed USH patients underwent electrophysiological examinations in the context of multimodal ophthalmological examination in the study (75 USH1, 189 USH2 and four USH3). Full-field electroretinography (ERG) was performed according to ISCEV standards, visual field determination was carried out with either the Octopus or Goldmann perimeters and visual acuity was examined with either ETDRS or Snellen charts. The data were compared between USH subtypes (USH1/USH2/USH3) and correlated with age. RESULTS Visual acuity decreases significantly with age for both USH1 and USH2 (p < 0.001), without a difference between the two cohorts. When corrected for age, the preserved kinetic visual field was significantly larger in USH2 than in USH1 (p = 0.04). Furthermore, the preserved kinetic visual field area showed a significant decrease with age (based on an exponential fit) in both USH1 and USH2 (p < 0.001). In USH1 patients, however, the visual field was already vastly reduced at an early age. The ERG results were abnormal in all patients. Detectable data for scotopic ERG were obtained from nine patients, and data of photopic ERG were obtained from 24 patients, without a difference between USH1 and USH2 subtypes. CONCLUSIONS There are differences in the phenotypes of RP in USH subtypes, most visible in the progression of visual fields between USH1 and USH2. The perimetric reduction occurs earlier in USH1 than in USH2. In both subtypes, visual acuity decreases significantly with age and the ERG is not detectable already at early ages.
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Affiliation(s)
- Katarina Stingl
- University Eye Hospital, Center for Ophthalmology, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany.
| | - Anne Kurtenbach
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
| | - Gesa Hahn
- University Eye Hospital, Center for Ophthalmology, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
| | - Christoph Kernstock
- University Eye Hospital, Center for Ophthalmology, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
| | - Stephanie Hipp
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
| | - Ditta Zobor
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
| | - Crystel Bonnet
- UMRS 1120, INSERM, Institut de la Vision, Sorbonne Université, 17 rue Moreau, 75012, Paris, France
| | - Saddek Mohand-Saïd
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, 17 rue Moreau, 75012, Paris, France.,DHU Sight Restore, INSERM-DHOS CIC1423, CHNO des Quinze-Vingts, 28 rue de Charenton, 75012, Paris, France
| | - Isabelle Audo
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, 17 rue Moreau, 75012, Paris, France.,DHU Sight Restore, INSERM-DHOS CIC1423, CHNO des Quinze-Vingts, 28 rue de Charenton, 75012, Paris, France
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Zaloška cesta 7, 1000, Ljubljana, Slovenia
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Zaloška cesta 7, 1000, Ljubljana, Slovenia
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Viale Abramo Lincoln, 5, 81100, Caserta, CE, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Viale Abramo Lincoln, 5, 81100, Caserta, CE, Italy
| | - Christine Petit
- UMRS 1120, INSERM, Institut de la Vision, Sorbonne Université, 17 rue Moreau, 75012, Paris, France.,Laboratory of Genetics and Physiology of Hearing, Institut Pasteur, 75015, Paris, France.,Collège de France, 11 place Marcelin-Berthelot, 75005, Paris, France
| | - Jose-Alain Sahel
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, 17 rue Moreau, 75012, Paris, France.,DHU Sight Restore, INSERM-DHOS CIC1423, CHNO des Quinze-Vingts, 28 rue de Charenton, 75012, Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, 29 Rue Manin, 75019, Paris, France.,Académie des Sciences-Institut de France, 23 quai de Conti, 75006, Paris, France.,Department of Ophthalmology, University of Pittsburgh School of Medicine, 203 Lothrop Street, Pittsburgh, PA, 15213, USA
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tuebingen, Elfriede-Aulhorn-Str. 7, 72076, Tuebingen, Germany
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39
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The photoreceptor cilium and its diseases. Curr Opin Genet Dev 2019; 56:22-33. [DOI: 10.1016/j.gde.2019.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/21/2019] [Accepted: 05/11/2019] [Indexed: 12/26/2022]
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40
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Jaiganesh A, Narui Y, Araya-Secchi R, Sotomayor M. Beyond Cell-Cell Adhesion: Sensational Cadherins for Hearing and Balance. Cold Spring Harb Perspect Biol 2018; 10:a029280. [PMID: 28847902 PMCID: PMC6008173 DOI: 10.1101/cshperspect.a029280] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cadherins form a large family of proteins often involved in calcium-dependent cellular adhesion. Although classical members of the family can provide a physical bond between cells, a subset of special cadherins use their extracellular domains to interlink apical specializations of single epithelial sensory cells. Two of these cadherins, cadherin-23 (CDH23) and protocadherin-15 (PCDH15), form extracellular "tip link" filaments that connect apical bundles of stereocilia on hair cells essential for inner-ear mechanotransduction. As these bundles deflect in response to mechanical stimuli from sound or head movements, tip links gate hair-cell mechanosensitive channels to initiate sensory perception. Here, we review the unusual and diverse structural properties of these tip-link cadherins and the functional significance of their deafness-related missense mutations. Based on the structural features of CDH23 and PCDH15, we discuss the elasticity of tip links and models that bridge the gap between the nanomechanics of cadherins and the micromechanics of hair-cell bundles during inner-ear mechanotransduction.
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Affiliation(s)
- Avinash Jaiganesh
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Yoshie Narui
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Raul Araya-Secchi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Marcos Sotomayor
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
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Kurtenbach A, Hahn G, Kernstock C, Hipp S, Zobor D, Stingl K, Kohl S, Bonnet C, Mohand-Saïd S, Sliesoraityte I, Sahel JA, Audo I, Fakin A, Hawlina M, Testa F, Simonelli F, Petit C, Zrenner E. Usher Syndrome and Color Vision. Curr Eye Res 2018; 43:1295-1301. [PMID: 30012035 DOI: 10.1080/02713683.2018.1501804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
PURPOSE The aim of this study is to report on the results of color vision testing in a European cohort of patients with Usher syndrome (USH). We describe the results in relation to Usher type (USH1 and USH2), age and visual acuity. METHODS AND METHODS The color vision of 220 genetically confirmed adult USH patients, aged 18-70 years, was analyzed with one of three methods: the Farnsworth D-15 Dichotomous test (D-15) along with the Lanthony desaturated 15 Hue tests (D-15d), the Roth 28-Hue test, or the Ishihara 14-plate test. Visual acuity was measured with either the ETDRS or the SNELLEN charts. The Confusion index, the Selectivity index and the Confusion angle were calculated for the panel tests and used for analysis. The numbers of plates that could not be read were analyzed for the Ishihara test. RESULTS For the panel tests, the degree of color loss (Confusion index) is similar in both subtypes of USH, but the polarization of error scores (Selectivity index) is significantly lower in USH1 than USH2, showing more diffuse errors than those found in USH2. There is no significant correlation between logMAR visual acuity and the Confusion or the Selectivity indices. Additionally, we find a significant correlation between patient age and the degree and the polarity of the loss only in USH2. There was no difference between USH1 and USH2 in the results of the Ishihara test. CONCLUSIONS The examination of color vision in patients with USH shows a significant difference in the pattern of color vision loss in USH1 and USH2 patients, but not in the severity of the loss. In USH2, we find a correlation between patient age and the degree and the polarity of the loss. These results may be due to differences in the pathogenesis of retinal dystrophy in USH1 and USH2.
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Affiliation(s)
- Anne Kurtenbach
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Gesa Hahn
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Christoph Kernstock
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Stephanie Hipp
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Ditta Zobor
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Katarina Stingl
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Susanne Kohl
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany
| | - Crystel Bonnet
- b Institut de la Vision , INSERM UMRS 1120 , Paris , France.,c Complexité du vivant , UPMC-Sorbonnes Universités , Paris , France
| | - Saddek Mohand-Saïd
- b Institut de la Vision , INSERM UMRS 1120 , Paris , France.,d Centre d'Investigation Clinique, Direction de l'Hospitalisation et de l'Organisation des Soins , Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts , Paris , France
| | | | - José-Alain Sahel
- b Institut de la Vision , INSERM UMRS 1120 , Paris , France.,c Complexité du vivant , UPMC-Sorbonnes Universités , Paris , France.,d Centre d'Investigation Clinique, Direction de l'Hospitalisation et de l'Organisation des Soins , Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts , Paris , France
| | - Isabelle Audo
- b Institut de la Vision , INSERM UMRS 1120 , Paris , France.,d Centre d'Investigation Clinique, Direction de l'Hospitalisation et de l'Organisation des Soins , Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts , Paris , France
| | - Ana Fakin
- f Eye Hospital , University Medical Centre Ljubljana , Ljubljana , Slovenia
| | - Marko Hawlina
- f Eye Hospital , University Medical Centre Ljubljana , Ljubljana , Slovenia
| | - Francesco Testa
- g Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences , University of Campania Luigi Vanvitelli , Naples , Italy
| | - Francesca Simonelli
- g Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences , University of Campania Luigi Vanvitelli , Naples , Italy
| | - Christine Petit
- b Institut de la Vision , INSERM UMRS 1120 , Paris , France.,c Complexité du vivant , UPMC-Sorbonnes Universités , Paris , France.,h , Collège de France , Paris , France.,i Génétique et Physiologie de l`Audition , Institut Pasteur , Paris , France
| | - Eberhart Zrenner
- a Centre for Ophthalmology, Institute for Ophthalmic Research , University of Tuebingen , Tuebingen , Germany.,j Werner Reichardt Centre for Integrative Neuroscience (CIN) , University of Tübingen , Tübingen , Germany
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Cone degeneration is triggered by the absence of USH1 proteins but prevented by antioxidant treatments. Sci Rep 2018; 8:1968. [PMID: 29386551 PMCID: PMC5792440 DOI: 10.1038/s41598-018-20171-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/04/2018] [Indexed: 11/26/2022] Open
Abstract
Usher syndrome type 1 (USH1) is a major cause of inherited deafness and blindness in humans. The eye disorder is often referred to as retinitis pigmentosa, which is characterized by a secondary cone degeneration following the rod loss. The development of treatments to prevent retinal degeneration has been hampered by the lack of clear evidence for retinal degeneration in mutant mice deficient for the Ush1 genes, which instead faithfully mimic the hearing deficit. We show that, under normal housing conditions, Ush1g−/− and Ush1c−/− albino mice have dysfunctional cone photoreceptors whereas pigmented knockout animals have normal photoreceptors. The key involvement of oxidative stress in photoreceptor apoptosis and the ensued retinal gliosis were further confirmed by their prevention when the mutant mice are reared under darkness and/or supplemented with antioxidants. The primary degeneration of cone photoreceptors contrasts with the typical forms of retinitis pigmentosa. Altogether, we propose that oxidative stress probably accounts for the high clinical heterogeneity among USH1 siblings, which also unveils potential targets for blindness prevention.
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Auditory cortex interneuron development requires cadherins operating hair-cell mechanoelectrical transduction. Proc Natl Acad Sci U S A 2017; 114:7765-7774. [PMID: 28705869 DOI: 10.1073/pnas.1703408114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Many genetic forms of congenital deafness affect the sound reception antenna of cochlear sensory cells, the hair bundle. The resulting sensory deprivation jeopardizes auditory cortex (AC) maturation. Early prosthetic intervention should revive this process. Nevertheless, this view assumes that no intrinsic AC deficits coexist with the cochlear ones, a possibility as yet unexplored. We show here that many GABAergic interneurons, from their generation in the medial ganglionic eminence up to their settlement in the AC, express two cadherin-related (cdhr) proteins, cdhr23 and cdhr15, that form the hair bundle tip links gating the mechanoelectrical transduction channels. Mutant mice lacking either protein showed a major decrease in the number of parvalbumin interneurons specifically in the AC, and displayed audiogenic reflex seizures. Cdhr15- and Cdhr23-expressing interneuron precursors in Cdhr23-/- and Cdhr15-/- mouse embryos, respectively, failed to enter the embryonic cortex and were scattered throughout the subpallium, consistent with the cell polarity abnormalities we observed in vitro. In the absence of adhesion G protein-coupled receptor V1 (adgrv1), another hair bundle link protein, the entry of Cdhr23- and Cdhr15-expressing interneuron precursors into the embryonic cortex was also impaired. Our results demonstrate that a population of newborn interneurons is endowed with specific cdhr proteins necessary for these cells to reach the developing AC. We suggest that an "early adhesion code" targets populations of interneuron precursors to restricted neocortical regions belonging to the same functional area. These findings open up new perspectives for auditory rehabilitation and cortical therapies in patients.
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