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Lewis TR, Klementieva NV, Phan S, Castillo CM, Kim KY, Cao LY, Ellisman MH, Arshavsky VY, Alekseev O. Human rod photoreceptor outer segments are supported by accessory inner segment structures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.09.607370. [PMID: 39149258 PMCID: PMC11326293 DOI: 10.1101/2024.08.09.607370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
The first steps in vision take place in photoreceptor cells, which are highly compartmentalized neurons exhibiting significant structural variation across species. The light-sensitive ciliary compartment, called the outer segment, is located atop of the cell soma, called the inner segment. In this study, we present an ultrastructural analysis of human photoreceptors, which reveals that, in contrast to this classic arrangement, the inner segment of human rods extends alongside the outer segment to form a structure hereby termed the "accessory inner segment". While reminiscent of the actin-based microvilli known as "calyceal processes" observed in other species, the accessory inner segment is a unique structure: (1) it contains an extensive microtubule-based cytoskeleton, (2) it extends far alongside the outer segment, (3) its diameter is comparable to that of the outer segment, (4) it contains numerous mitochondria, and (5) it forms electron-dense structures that likely mediate adhesion to the outer segment. Given that the spacing of extrafoveal human photoreceptors is more sparse than in non-primate species, with vast amounts of interphotoreceptor matrix present between cells, the closely apposed accessory inner segment likely provides structural support to the outer segment. This discovery expands our understanding of the human retina and directs future studies of human photoreceptor function in health and disease.
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Affiliation(s)
- Tylor R. Lewis
- Department of Ophthalmology, Duke University, Durham, NC
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, AL
| | | | - Sebastien Phan
- National Center for Microscopy and Imaging Research, Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA
| | | | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA
| | - Lauren Y. Cao
- Department of Ophthalmology, Duke University, Durham, NC
| | - Mark H. Ellisman
- National Center for Microscopy and Imaging Research, Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA
| | - Vadim Y. Arshavsky
- Department of Ophthalmology, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
| | - Oleg Alekseev
- Department of Ophthalmology, Duke University, Durham, NC
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Major L, McClements ME, MacLaren RE. A Review of CRISPR Tools for Treating Usher Syndrome: Applicability, Safety, Efficiency, and In Vivo Delivery. Int J Mol Sci 2023; 24:ijms24087603. [PMID: 37108761 PMCID: PMC10146473 DOI: 10.3390/ijms24087603] [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: 03/10/2023] [Revised: 04/12/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
This review considers research into the treatment of Usher syndrome, a deaf-blindness syndrome inherited in an autosomal recessive manner. Usher syndrome mutations are markedly heterogeneous, involving many different genes, and research grants are limited due to minimal patient populations. Furthermore, gene augmentation therapies are impossible in all but three Usher syndromes as the cDNA sequence exceeds the 4.7 kb AAV packaging limit. It is, therefore, vital to focus research efforts on alternative tools with the broadest applicability. The CRISPR field took off in recent years following the discovery of the DNA editing activity of Cas9 in 2012. New generations of CRISPR tools have succeeded the original CRISPR/Cas9 model to enable more sophisticated genomic amendments such as epigenetic modification and precise sequence alterations. This review will evaluate the most popular CRISPR tools to date: CRISPR/Cas9, base editing, and prime editing. It will consider these tools in terms of applicability (in relation to the ten most prevalent USH2A mutations), safety, efficiency, and in vivo delivery potential with the intention of guiding future research investment.
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Affiliation(s)
- Lauren Major
- Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Michelle E McClements
- Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Robert E MacLaren
- Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences & NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
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Zaw K, Carvalho LS, Aung-Htut MT, Fletcher S, Wilton SD, Chen FK, McLenachan S. Pathogenesis and Treatment of Usher Syndrome Type IIA. Asia Pac J Ophthalmol (Phila) 2022; 11:369-379. [PMID: 36041150 DOI: 10.1097/apo.0000000000000546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/27/2022] [Indexed: 12/16/2022] Open
Abstract
Usher syndrome (USH) is the most common form of deaf-blindness, with an estimated prevalence of 4.4 to 16.6 per 100,000 people worldwide. The most common form of USH is type IIA (USH2A), which is caused by homozygous or compound heterozygous mutations in the USH2A gene and accounts for around half of all USH cases. USH2A patients show moderate to severe hearing loss from birth, with diagnosis of retinitis pigmentosa in the second decade of life and variable vestibular involvement. Although hearing aids or cochlear implants can provide some mitigation of hearing deficits, there are currently no treatments aimed at preventing or restoring vision loss in USH2A patients. In this review, we first provide an overview of the molecular biology of the USH2A gene and its protein isoforms, which include a transmembrane protein (TM usherin) and an extracellular protein (EC usherin). The role of these proteins in the inner ear and retina and their impact on the pathogenesis of USH2A is discussed. We review animal cell-derived and patient cell-derived models currently used in USH2A research and conclude with an overview of potential treatment strategies currently in preclinical development and clinical trials.
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Affiliation(s)
- Khine Zaw
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Livia S Carvalho
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
| | - May T Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Murdoch, Western Australia, Australia
- Perron Institute for Neurological and Translational Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia
| | - Samuel McLenachan
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia
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Deafness-related protein PDZD7 forms complex with the C-terminal tail of FCHSD2. Biochem J 2022; 479:1393-1405. [PMID: 35695292 PMCID: PMC9317961 DOI: 10.1042/bcj20220147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 11/24/2022]
Abstract
In cochlea, deafness-related protein PDZD7 is an indispensable component of the ankle link complex, which is critical for the maturation of inner-ear hair cell for sound perception. Ankle links, connecting the different rows of cochlear stereocilia, are essential for the staircase-like development of stereocilia. However, the molecular mechanism of how PDZD7 governs stereociliary development remains unknown. Here, we reported a novel PDZD7-binding partner, FCHSD2, identified by yeast two-hybrid screening. FCHSD2 was reported to be expressed in hair cell, where it co-operated with CDC42 and N-WASP to regulate the formation of cell protrusion. The association between FCHSD2 and PDZD7 was further confirmed in COS-7 cells. More importantly, we solved the complex structure of FCHSD2 tail with PDZD7 PDZ3 domain at 2.0 Å resolution. The crystal structure shows that PDZD7 PDZ3 adopts a typical PDZ domain topology, comprising five β strands and two α helixes. The PDZ-binding motif of FCHSD2 tail stretches through the αB/βB groove of PDZD7 PDZ3. Our study not only uncovers the interaction between FCHSD2 tail and PDZD7 PDZ3 at the atomic level, but also provides clues of connecting the ankle link complex with cytoskeleton dynamics for exploiting the molecular mechanism of stereociliary development.
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Schroeder M, Peter VG, Gränse L, Andréasson S, Rivolta C, Kjellström U. A novel phenotype associated with the R162W variant in the KCNJ13 gene. Ophthalmic Genet 2022; 43:500-507. [PMID: 35477418 DOI: 10.1080/13816810.2022.2068041] [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: 10/18/2022]
Abstract
BACKGROUND Pathogenic variants in KCNJ13 have been associated with both autosomal dominant Snowflake vitreoretinal degeneration (SVD) and autosomal recessive Leber congenital amaurosis. SVD is characterized by aberrant vitreoretinal interface leading to increased risk of retinal detachment, crystalline retinal snowflake deposits, optic disc abnormalities, early-onset cataract, and cornea guttae. Reduced dark adaptation and reduced scotopic rod b-waves have also been described. We report a novel phenotype associated with the R162W variant in KCNJ13. METHODS Four affected members of a Swedish family were included. Three of them were examined with best corrected visual acuity, Goldmann perimetry, full-field-and multifocal electroretinography, optical coherence tomography, fundus color photographs, fundus autofluorescence images, slit lamp inspection, and genetic testing. The fourth subject only managed genetic testing. RESULTS All subjects carry the pathogenic missense variant; c.484C>T (NM_002242.4), R162W, in KCNJ13. ERG measurements revealed reduced macular-as well as general retinal function. Two of the subjects had a history of retinal detachment and the two younger subjects demonstrated early onset cataract. They all had structural macular changes and slightly gliotic optic discs. CONCLUSION In this family, the R162W variant in KCNJ13, previously described in association with SVD, causes a somewhat novel phenotype including macular dystrophy and moderate reduction of general retinal function as the main features combined with disc abnormalities, retinal detachment, and presenile cataract that has been described before. In times of up-coming gene-based therapies, it is important to report new genotype-phenotype associations to improve the possibilities to identify future treatment candidates.
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Affiliation(s)
- Marion Schroeder
- Department of Ophthalmology and Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Virginie G Peter
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.,Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Lotta Gränse
- Department of Ophthalmology and Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Sten Andréasson
- Department of Ophthalmology and Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Carlo Rivolta
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.,Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Ulrika Kjellström
- Department of Ophthalmology and Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
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Hunt H, Dittmer KE, Garrick DJ, Fairley RA, Heap SJ, Jolly RD. An inherited night blindness in Wiltshire sheep. Vet Pathol 2022; 59:310-318. [PMID: 34974772 DOI: 10.1177/03009858211067461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Twelve cases of adult-onset blindness were identified in a flock of 130 polled Wiltshire sheep in New Zealand over a 3-year period. Affected sheep developed night blindness between 2 and 3 years of age, which progressed to complete blindness by 4 to 5 years of age. Fundic examination findings included progressive tapetal hyperreflectivity and attenuation of retinal blood vessels. Histologically, the retinas had a selective loss of rod photoreceptors with initial preservation of cone photoreceptors. Retinal degeneration was not accompanied by any other ocular or central nervous system abnormalities, and pedigree analysis suggested an inherited basis for the disease. Mating an affected Wiltshire ram to 2 affected Wiltshire ewes resulted in 6 progeny that all developed retinal degeneration by 2 years of age, while mating of the same affected ram to 6 unaffected ewes resulted in 8 unaffected progeny, consistent with autosomal recessive inheritance. Homozygosity mapping of 5 affected Wiltshire sheep and 1 unaffected Wiltshire sheep using an OvineSNP50 Genotyping BeadChip revealed an identical-by-descent region on chromosome 5, but none of the genes within this region were considered plausible candidate genes. Whole-genome sequencing of 2 affected sheep did not reveal any significant mutations in any of the genes associated with retinitis pigmentosa in humans or progressive retinal atrophy in dogs. Inherited progressive retinal degeneration affecting rod photoreceptors has not been previously reported in sheep, but this disease has several similarities to inherited retinal dystrophies in other species.
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Affiliation(s)
- Hayley Hunt
- Massey University, Palmerston North, New Zealand
| | | | | | | | - Stephen J Heap
- McMaster and Heap Veterinary Practice, Christchurch, New Zealand
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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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Genetics, pathogenesis and therapeutic developments for Usher syndrome type 2. Hum Genet 2021; 141:737-758. [PMID: 34331125 DOI: 10.1007/s00439-021-02324-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/24/2021] [Indexed: 12/28/2022]
Abstract
Usher syndrome (USH) is a rare, autosomal recessively inherited disorder resulting in a combination of sensorineural hearing loss and a progressive loss of vision resulting from retinitis pigmentosa (RP), occasionally accompanied by an altered vestibular function. More and more evidence is building up indicating that also sleep deprivation, olfactory dysfunction, deficits in tactile perception and reduced sperm motility are part of the disease etiology. USH can be clinically classified into three different types, of which Usher syndrome type 2 (USH2) is the most prevalent. In this review, we, therefore, assess the genetic and clinical aspects, available models and therapeutic developments for USH2. Mutations in USH2A, ADGRV1 and WHRN have been described to be responsible for USH2, with USH2A being the most frequently mutated USH-associated gene, explaining 50% of all cases. The proteins encoded by the USH2 genes together function in a dynamic protein complex that, among others, is found at the photoreceptor periciliary membrane and at the base of the hair bundles of inner ear hair cells. To unravel the pathogenic mechanisms underlying USH2, patient-derived cellular models and animal models including mouse, zebrafish and drosophila, have been generated that all in part mimic the USH phenotype. Multiple cellular and genetic therapeutic approaches are currently under development for USH2, mainly focused on preserving or partially restoring the visual function of which one is already in the clinical phase. These developments are opening a new gate towards a possible treatment for USH2 patients.
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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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Meng X, Liu X, Li Y, Guo T, Yang L. Correlation between Genotype and Phenotype in 69 Chinese Patients with USH2A Mutations: A comparative study of the patients with Usher Syndrome and Nonsyndromic Retinitis Pigmentosa. Acta Ophthalmol 2021; 99:e447-e460. [PMID: 33124170 DOI: 10.1111/aos.14626] [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: 04/06/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE The aim of this study was to analyse 69 Chinese patients with USH2A mutations and to assess the genotype-phenotype correlation. METHODS All 36 Usher syndrome type IIA patients and 33 nonsyndromic RP (retinitis pigmentosa) patients underwent clinical examinations. Eye examinations included best-corrected visual acuity, slit-lamp biomicroscopy, fundus examination with dilated pupils, fundus fluorescent angiography, visual field test, full-field electroretinography and optic coherence tomography; audiological assessment included pure tone audiometry and hearing thresholds. The molecular diagnosis of genotype combined the single-gene Sanger sequencing and next-generation sequencing. This study is a retrospective study. RESULTS The mean age of first symptoms with Usher syndrome type IIa and nonsyndromic RP patients was 13.7 versus 29.8 years (ocular phenotypes, p < 0.001); 17.7 versus 29.9 years (nyctalopia, p < 0.001); 44.7 versus 54.8 years (low vision based on VF, p < 0.001); 41.7 versus 54.7 years (low vision based on VA, p < 0.001); and 46.0 versus 56.7 years (legal blindness based on VF, p < 0.001). There was significant difference in variants in the two groups (p < 0.05). Among patients with mutation c.2802T > G (p.Cys934Trp), more (66.7%) presented with normal hearing. All patients (3/3, 100%) with the variant c.8232G > C (p.Trp2744Cys) had hearing loss. Furthermore, we identified 23 novel variants in USH2A. CONCLUSIONS Patients with Usher syndrome type IIa had an earlier onset of the disease, inferior visual function and presented with more truncating variants, compared with the nonsyndromic RP patients.
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Affiliation(s)
- Xiang Meng
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - XiaoZhen Liu
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - YingYing Li
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - Tong Guo
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
| | - Liping Yang
- Department of Ophthalmology Peking University Third Hospital Beijing Key Laboratory of Restoration of Damaged Ocular Nerve Beijing China
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Whatley M, Francis A, Ng ZY, Khoh XE, Atlas MD, Dilley RJ, Wong EYM. Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy. Front Genet 2020; 11:565216. [PMID: 33193648 PMCID: PMC7642844 DOI: 10.3389/fgene.2020.565216] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022] Open
Abstract
Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped. The proteins encoded by these genes form complexes that play critical roles in the development and maintenance of cellular structures within the inner ear and retina, which have minimal capacity for repair or regeneration. In the cochlea, stereocilia are located on the apical surface of inner ear hair cells (HC) and are responsible for transducing mechanical stimuli from sound pressure waves into chemical signals. These signals are then detected by the auditory nerve fibers, transmitted to the brain and interpreted as sound. Disease-causing mutations in USH genes can destabilize the tip links that bind the stereocilia to each other, and cause defects in protein trafficking and stereocilia bundle morphology, thereby inhibiting mechanosensory transduction. This review summarizes the current knowledge on Usher syndrome with a particular emphasis on mutations in USH genes, USH protein structures, and functional analyses in animal models. Currently, there is no cure for USH. However, the genetic therapies that are rapidly developing will benefit from this compilation of detailed genetic information to identify the most effective strategies for restoring functional USH proteins.
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Affiliation(s)
- Meg Whatley
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Abbie Francis
- Ear Science Institute Australia, Nedlands, WA, Australia
- Emergency Medicine, The University of Western Australia, Nedlands, WA, Australia
| | - Zi Ying Ng
- Ear Science Institute Australia, Nedlands, WA, Australia
| | - Xin Ee Khoh
- Ear Science Institute Australia, Nedlands, WA, Australia
- School of Human Sciences, The University of Western Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
| | - Rodney J. Dilley
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, The University of Western Australia, Perth, WA, Australia
| | - Elaine Y. M. Wong
- Ear Science Institute Australia, Nedlands, WA, Australia
- Ear Sciences Centre, The University of Western Australia, Nedlands, WA, Australia
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Bentley, WA, Australia
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Zou J, Li R, Wang Z, Yang J. Studies of the Periciliary Membrane Complex in the Syrian Hamster Photoreceptor. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:543-547. [PMID: 31884668 DOI: 10.1007/978-3-030-27378-1_89] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Mutations in USH2A, ADGRV1, and WHRN genes cause Usher syndrome type 2 (USH2) and retinitis pigmentosa (RP). The proteins encoded by these genes form the periciliary membrane complex (PMC) in photoreceptors. Unlike patients, who show retinal degeneration in their second decade of life, mice carrying USH2 mutations have very-late-onset retinal degeneration, although the PMC is disrupted. A similar weak retinal degeneration phenotype was also reported in ush2a mutant zebrafish. The lack of appropriate USH2 animal models hinders our understanding on PMC function in photoreceptors and retinal pathogenesis caused by USH2 mutations. In this study, we examined the molecular composition of the PMC and the morphology of the PMC and its surrounding subcellular structure in Syrian hamster photoreceptors. We demonstrate that the PMC and its neighboring structure in hamsters are similar to those in mice. Therefore, the Syrian hamster may not offer advantages over the mouse as an animal model for USH2 pathogenic studies.
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Affiliation(s)
- Junhuang Zou
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Rong Li
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, USA
| | - Zhongde Wang
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, USA
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT, USA.
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA.
- Department of Surgery, Division of Otolaryngology, University of Utah, Salt Lake City, UT, USA.
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Wang L, Wei B, Fu X, Wang Y, Sui Y, Ma J, Gong X, Hao J, Xing S. Identification of whirlin domains interacting with espin: A study of the mechanism of Usher syndrome type II. Mol Med Rep 2019; 20:5111-5117. [PMID: 31638198 PMCID: PMC6854525 DOI: 10.3892/mmr.2019.10728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/19/2019] [Indexed: 11/23/2022] Open
Abstract
Usher syndrome is the most common condition of combined blindness and deafness and is classified into three types (USH1-USH3). USH2 is the most commonly diagnosed of all Usher syndrome cases. There are three identified proteins (usherin, GPR98 and whirlin) that form the USH2 complex. Defects in any of these proteins may cause failure in the formation of the USH2 complex, which is the primary cause of USH2. Whirlin is a scaffold protein and is essential for the assembly of the USH2 protein complex. It has been reported that espin is an interacting partner protein for whirlin. However, which fragment of whirlin interacts with espin remains unclear. In the present study, whirlin N- and C-terminal fragments in the pEGFP-C2 vectors were constructed. The recombinant plasmids were transfected into COS-7 cells to observe the co-localization by confocal laser scanning microscopy. The interactions between whirlin and espin were investigated by co-immunoprecipitation using the 293 cell line. It was demonstated that only the whirlin N-terminal fragment was able to interact with espin and the PR (proline-rich) region in whirlin may be important for the interaction. However, the present study did not investigate the interaction between whirlin and espin without the PR domain which warrants future research. Our findings elucidated a primary mechanism of interaction between whirlin and espin, which are crucial for further study on the USH2 complex and USH2 pathogenesis.
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Affiliation(s)
- Le Wang
- Department of Ophthalmology, First Hospital, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Bo Wei
- Department of Neurosurgery, China‑Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China
| | - Xueqi Fu
- Edmond H. Fischer Signal Transduction Laboratory, School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Yuchen Wang
- Edmond H. Fischer Signal Transduction Laboratory, School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Yuan Sui
- Edmond H. Fischer Signal Transduction Laboratory, School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Junfeng Ma
- Edmond H. Fischer Signal Transduction Laboratory, School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Xianhui Gong
- Department of Opthalmology, Eye Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Jilong Hao
- Department of Ophthalmology, First Hospital, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Shu Xing
- Edmond H. Fischer Signal Transduction Laboratory, School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
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Zou J, Chen Q, Almishaal A, Mathur PD, Zheng T, Tian C, Zheng QY, Yang J. The roles of USH1 proteins and PDZ domain-containing USH proteins in USH2 complex integrity in cochlear hair cells. Hum Mol Genet 2017; 26:624-636. [PMID: 28031293 DOI: 10.1093/hmg/ddw421] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 12/07/2016] [Indexed: 11/14/2022] Open
Abstract
Usher syndrome (USH) is the most common cause of inherited deaf-blindness, manifested as USH1, USH2 and USH3 clinical types. The protein products of USH2 causative and modifier genes, USH2A, ADGRV1, WHRN and PDZD7, interact to assemble a multiprotein complex at the ankle link region of the mechanosensitive stereociliary bundle in hair cells. Defects in this complex cause stereociliary bundle disorganization and hearing loss. The four USH2 proteins also interact in vitro with USH1 proteins including myosin VIIa, USH1G (SANS), CIB2 and harmonin. However, it is unclear whether the interactions between USH1 and USH2 proteins occur in vivo and whether USH1 proteins play a role in USH2 complex assembly in hair cells. In this study, we identified a novel interaction between myosin VIIa and PDZD7 by FLAG pull-down assay. We further investigated the role of the above-mentioned four USH1 proteins in the cochlear USH2 complex assembly using USH1 mutant mice. We showed that only myosin VIIa is indispensable for USH2 complex assembly at ankle links, indicating the potential transport and/or anchoring role of myosin VIIa for USH2 proteins in hair cells. However, myosin VIIa is not required for USH2 complex assembly in photoreceptors. We further showed that, while PDZ protein harmonin is not involved, its paralogous USH2 proteins, PDZD7 and whirlin, function synergistically in USH2 complex assembly in cochlear hair cells. In summary, our studies provide novel insight into the functional relationship between USH1 and USH2 proteins in the cochlea and the retina as well as the disease mechanisms underlying USH1 and USH2.
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Affiliation(s)
- Junhuang Zou
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Qian Chen
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Ali Almishaal
- Department of Communication Sciences and Disorders, University of Utah, 390 South 1530 East, Salt Lake City, UT 84112, USA
| | - Pranav Dinesh Mathur
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA.,Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT 84132, USA
| | - Tihua Zheng
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA
| | - Cong Tian
- Department of Otolaryngology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Qing Y Zheng
- Department of Otolaryngology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA.,Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT 84132, USA.,Division of Otolaryngology, Department of Surgery, University of Utah, 50 North Medical Drive, Salt Lake City, UT 84132, USA
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15
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Sengillo JD, Cabral T, Schuerch K, Duong J, Lee W, Boudreault K, Xu Y, Justus S, Sparrow JR, Mahajan VB, Tsang SH. Electroretinography Reveals Difference in Cone Function between Syndromic and Nonsyndromic USH2A Patients. Sci Rep 2017; 7:11170. [PMID: 28894305 PMCID: PMC5593892 DOI: 10.1038/s41598-017-11679-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 08/15/2017] [Indexed: 11/23/2022] Open
Abstract
Usher syndrome is an inherited and irreversible disease that manifests as retinitis pigmentosa (RP) and bilateral neurosensory hearing loss. Mutations in Usherin 2A (USH2A) are not only a frequent cause of Usher syndrome, but also nonsyndromic RP. Although gene- and cell-based therapies are on the horizon for RP and Usher syndrome, studies characterizing natural disease are lacking. In this retrospective analysis, retinal function of USH2A patients was quantified with electroretinography. Both groups had markedly reduced rod and cone responses, but nonsyndromic USH2A patients had 30 Hz-flicker electroretinogram amplitudes that were significantly higher than syndromic patients, suggesting superior residual cone function. There was a tendency for Usher syndrome patients to have a higher distribution of severe mutations, and alleles in this group had a higher odds of containing nonsense or frame-shift mutations. These data suggest that the previously reported severe visual phenotype seen in syndromic USH2A patients could relate to a greater extent of cone dysfunction. Additionally, a genetic threshold may exist where mutation burden relates to visual phenotype and the presence of hearing deficits. The auditory phenotype and allelic hierarchy observed among patients should be considered in prospective studies of disease progression and during enrollment for future clinical trials.
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Affiliation(s)
- Jesse D Sengillo
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Thiago Cabral
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Department of Ophthalmology, Federal University of Espírito Santo, Vitoria, Brazil.,Department of Ophthalmology, Federal University of São Paulo, Sao Paulo, Brazil
| | - Kaspar Schuerch
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Jimmy Duong
- Department of Biostatistics, Columbia University, New York, NY, USA
| | - Winston Lee
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Katherine Boudreault
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Department of Ophthalmology, University of Montreal, Montreal, Canada
| | - Yu Xu
- Department of Ophthalmology, Xin Hua Hospital affiliate of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sally Justus
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Janet R Sparrow
- Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Department of Pathology & Cell Biology, Stem Cell Initiative (CSCI), Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Vinit B Mahajan
- Omics Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, CA, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA. .,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA. .,Department of Pathology & Cell Biology, Stem Cell Initiative (CSCI), Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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16
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Yao L, Zhang L, Qi LS, Liu W, An J, Wang B, Xue JH, Zhang ZM. The Time Course of Deafness and Retinal Degeneration in a Kunming Mouse Model for Usher Syndrome. PLoS One 2016; 11:e0155619. [PMID: 27186975 PMCID: PMC4871471 DOI: 10.1371/journal.pone.0155619] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 05/02/2016] [Indexed: 01/13/2023] Open
Abstract
Usher syndrome is a group of autosomal recessive diseases characterized by congenital deafness and retinitis pigmentosa. In a mouse model for Usher syndrome, KMush/ush, discovered in our laboratory, we measured the phenotypes, characterized the architecture and morphology of the retina, and quantified the level of expression of pde6b and ush2a between postnatal (P) days 7, and 56. Electroretinograms and auditory brainstem response were used to measure visual and auditory phenotypes. Fundus photography and light microscopy were used to measure the architecture and morphology of the retina. Quantitative real-time PCR was used to measure the expression levels of mRNA. KMush/ush mice had low amplitudes and no obvious waveforms of Electroretinograms after P14 compared with controls. Thresholds of auditory brainstem response in our model were higher than those of controls after P14. By P21, the retinal vessels of KMush/ush mice were attenuated and their optic discs had a waxy pallor. The retinas of KMush/ush mice atrophied and the choroidal vessels were clearly visible. Notably, the architecture of each retinal layer was not different as compared with control mice at P7, while the outer nuclear layer (ONL) and other retinal layers of KMush/ush mice were attenuated significantly between P14 and P21. ONL cells were barely seen in KMush/ush mice at P56. As compared with control mice, the expression of pde6b and ush2a in KMush/ush mice declined significantly after P7. This study is a first step toward characterizing the progression of disease in our mouse model. Future studies using this model may provide insights about the etiology of the disease and the relationships between genotypes and phenotypes providing a valuable resource that could contribute to the foundation of knowledge necessary to develop therapies to prevent the retinal degeneration in patients with Usher Syndrome.
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Affiliation(s)
- Lu Yao
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Lei Zhang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Lin-Song Qi
- Department of Physical Examination, Air Force General Hospital, 30 Fucheng Road, Beijing, China
| | - Wei Liu
- Medical Experiment Center, Shaanxi University of Chinese Medicine, Shiji Ave., Xi'an-Xianyang New Ecomic Zone, 712046, Xi'an, China
| | - Jing An
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Bin Wang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
| | - Jun-Hui Xue
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
- * E-mail: (JHX); (ZMZ)
| | - Zuo-Ming Zhang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, 169 West Changle Road, Xi'an, China
- * E-mail: (JHX); (ZMZ)
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17
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Sliesoraityte I, Peto T, Mohand-Said S, Sahel JA. Novel grading system for quantification of cystic macular lesions in Usher syndrome. Orphanet J Rare Dis 2015; 10:157. [PMID: 26654877 PMCID: PMC4676164 DOI: 10.1186/s13023-015-0372-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/25/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To evaluate novel grading system used to quantify optical coherence tomography (OCT) scans for cystic macular lesions (CML) in Usher syndrome (USH) patients, focusing on CML associated alterations in MOY7A and USH2A mutations. METHODS Two readers evaluated 76 patients' (mean age 42 ± 14 years) data prospectively uploaded on Eurush database. OCT was used to obtain high quality cross-sectional images through the fovea. The CML was graded as none, mild, moderate or severe, depending on the following features set: subretinal fluid without clearly detectable CML boundaries; central macular thickness; largest diameter of CML; calculated mean of all detectable CML; total number of detectable CML; retinal layers affected by CML. Intra-and inter-grader reproducibility was evaluated. RESULTS CML were observed in 37 % of USH eyes, while 45 % were observed in MYO7A and 29 % in USH2A cases. Of those with CML: 52 % had mild, 22 % had moderate and 26 % had severe changes, respectively. CML were found in following retinal layers: 50 % inner nuclear layer, 44 % outer nuclear layer, 6 % retinal ganglion cell layer. For the inter-grader repeatability analysis, agreements rates for CML were 97 % and kappa statistics was 0.91 (95 % CI 0.83-0.99). For the intra-grader analysis, agreement rates for CML were 98 %, while kappa statistics was 0.96 (95 % CI 0.92-0.99). CONCLUSIONS The novel grading system is a reproducible tool for grading OCT images in USH complicated by CML, and potentially could be used for objective tracking of macular pathology in clinical therapy trials.
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Affiliation(s)
- Ieva Sliesoraityte
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1243, 28 rue de Charenton, 75012, Paris, France.
| | - Tunde Peto
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, 162 City Road, ECV1 2PD, London, UK
| | - Saddek Mohand-Said
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1243, 28 rue de Charenton, 75012, Paris, France
| | - Jose Alain Sahel
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1243, 28 rue de Charenton, 75012, Paris, France.,INSERM, CNRS, Institut de la Vision, Sorbonne Universités, UPMC Univ Paris 06, 17 rue Moreau, 75012, Paris, France
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18
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A novel mutation of the USH2C (GPR98) gene in an Iranian family with Usher syndrome type II. J Genet 2014; 93:837-41. [DOI: 10.1007/s12041-014-0443-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Mathur P, Yang J. Usher syndrome: Hearing loss, retinal degeneration and associated abnormalities. Biochim Biophys Acta Mol Basis Dis 2014; 1852:406-20. [PMID: 25481835 DOI: 10.1016/j.bbadis.2014.11.020] [Citation(s) in RCA: 222] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/25/2014] [Accepted: 11/26/2014] [Indexed: 02/06/2023]
Abstract
Usher syndrome (USH), clinically and genetically heterogeneous, is the leading genetic cause of combined hearing and vision loss. USH is classified into three types, based on the hearing and vestibular symptoms observed in patients. Sixteen loci have been reported to be involved in the occurrence of USH and atypical USH. Among them, twelve have been identified as causative genes and one as a modifier gene. Studies on the proteins encoded by these USH genes suggest that USH proteins interact among one another and function in multiprotein complexes in vivo. Although their exact functions remain enigmatic in the retina, USH proteins are required for the development, maintenance and function of hair bundles, which are the primary mechanosensitive structure of inner ear hair cells. Despite the unavailability of a cure, progress has been made to develop effective treatments for this disease. In this review, we focus on the most recent discoveries in the field with an emphasis on USH genes, protein complexes and functions in various tissues as well as progress toward therapeutic development for USH.
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Affiliation(s)
- Pranav Mathur
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA; Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA; Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132, USA; Department of Otolaryngology Head and Neck Surgery, University of Utah, Salt Lake City, UT 84132, USA.
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20
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Zenner HP, Pfister M, Friese N, Zrenner E, Röcken M. [Personalized molecular medicine: new paradigms in the treatment of cochlear implant and cancer patients]. HNO 2014; 62:520-4. [PMID: 24920503 DOI: 10.1007/s00106-014-2859-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To evaluate present options for the indication of cochlear implants (CI) and new forms of treatment for head and neck cancer, melanomas and basal cell carcinomas, with emphasis on future perspectives. METHODS A literature search was performed in the PubMed database. Search parameters were "personalized medicine", "individualized medicine" and "molecular medicine". RESULTS Personalized medicine based on molecular-genetic evaluation of functional proteins such as otoferlin, connexin 26 and KCNQ4 or the Usher gene is becoming increasingly important for the indication of CI in the context of infant deafness. Determination of HER2/EGFR mutations in the epithelial growth factor receptor (EGFR) gene may be an important prognostic parameter for therapeutic decisions in head and neck cancer patients. In basal cell carcinoma therapy, mutations in the Hedgehog (PCTH1) and Smoothened (SMO) pathways strongly influence the indication of therapeutic Hedgehog inhibition, e.g. using small molecules. Analyses of c-Kit receptor, BRAF-600E and NRAS mutations are required for specific molecular therapy of metastasizing melanomas. The significant advances in the field of specific molecular therapy are best illustrated by the availability of the first gene therapeutic procedures for treatment of RPE65-induced infantile retinal degradation. CONCLUSION The aim of personalized molecular medicine is to identify patients who will respond particularly positively or negatively (e.g. in terms of adverse side effects) to a therapy using the methods of molecular medicine. This should allow a specific therapy to be successfully applied or preclude its indication in order to avoid serious adverse side effects. This approach serves to stratify patients for adequate treatment.
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Affiliation(s)
- H P Zenner
- Universitätsklinik für HNO-Heilkunde, Universität Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Deutschland,
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Localization of PDZD7 to the stereocilia ankle-link associates this scaffolding protein with the Usher syndrome protein network. J Neurosci 2013; 32:14288-93. [PMID: 23055499 DOI: 10.1523/jneurosci.3071-12.2012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Usher syndrome is the leading cause of genetic deaf-blindness. Monoallelic mutations in PDZD7 increase the severity of Usher type II syndrome caused by mutations in USH2A and GPR98, which respectively encode usherin and GPR98. PDZ domain-containing 7 protein (PDZD7) is a paralog of the scaffolding proteins harmonin and whirlin, which are implicated in Usher type 1 and type 2 syndromes. While usherin and GPR98 have been reported to form hair cell stereocilia ankle-links, harmonin localizes to the stereocilia upper tip-link density and whirlin localizes to both tip and ankle-link regions. Here, we used mass spectrometry to show that PDZD7 is expressed in chick stereocilia at a comparable molecular abundance to GPR98. We also show by immunofluorescence and by overexpression of tagged proteins in rat and mouse hair cells that PDZD7 localizes to the ankle-link region, overlapping with usherin, whirlin, and GPR98. Finally, we show in LLC-PK1 cells that cytosolic domains of usherin and GPR98 can bind to both whirlin and PDZD7. These observations are consistent with PDZD7 being a modifier and candidate gene for USH2, and suggest that PDZD7 is a second scaffolding component of the ankle-link complex.
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22
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Zou J, Lee A, Yang J. The expression of whirlin and Cav1.3α₁ is mutually independent in photoreceptors. Vision Res 2012; 75:53-9. [PMID: 22892111 DOI: 10.1016/j.visres.2012.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/27/2012] [Accepted: 07/30/2012] [Indexed: 12/18/2022]
Abstract
Whirlin is a gene responsible for Usher syndrome type II (USH2) and congenital deafness. In photoreceptors, it organizes a protein complex through binding to proteins encoded by other USH2 genes, usherin (USH2A) and G-protein-coupled receptor 98 (GPR98). Recently, Ca(v)1.3α(1) (α(1D)) has been discovered to interact with whirlin in vitro and these two proteins are localized to the same subcellular compartments in photoreceptors. Accordingly, it is proposed that Ca(v)1.3α(1) is in the USH2 protein complex and that the USH2 protein complex is involved in regulating Ca(2+) in photoreceptors. To test this hypothesis, we investigated the interdependence of Ca(v)1.3α(1) and whirlin expression in photoreceptors. We found that lack of Ca(v)1.3α(1) did not change the whirlin distribution or expression level in photoreceptors. In the retina, several Ca(v)1.3α(1) splice variants were found at the RNA level. Among them, the whirlin-interacting Ca(v)1.3α(1) long variant had no change in its protein expression level in the absence of whirlin. The localization of Ca(v)1.3α(1) in photoreceptors, published previously, cannot be confirmed. Therefore, the mutual independence of whirlin and Ca(v)1.3α(1) expressions in photoreceptors suggests that Ca(v)1.3α(1) may not be a key member of the USH2 protein complex at the periciliary membrane complex.
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Affiliation(s)
- Junhuang Zou
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT 84132, United States
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