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da Palma MM, Marra M, Igelman AD, Ku CA, Burr A, Andersen K, Everett LA, Porto FBO, Sallum JMF, Yang P, Pennesi ME. Expanding the phenotypic and genotypic spectrum of patients with HGSNAT-related retinopathy. Ophthalmic Genet 2024; 45:167-174. [PMID: 37592806 DOI: 10.1080/13816810.2023.2245035] [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: 03/12/2023] [Accepted: 08/01/2023] [Indexed: 08/19/2023]
Abstract
BACKGROUND Variants in HGSNAT have historically been associated with syndromic mucopolysaccharidosis type IIIC (MPSIIIC) but more recent studies demonstrate cases of HGSNAT-related non-syndromic retinitis pigmentosa. We describe and expand the genotypic and phenotypic spectrum of this disease. MATERIALS AND METHODS This is a retrospective, observational, case series of 11 patients with pericentral retinitis pigmentosa due to variants in HGSNAT gene without a syndromic diagnosis of MPSIIIC. We reviewed ophthalmologic data extracted from medical records, genetic testing, color fundus photos, fundus autofluorescence (FAF), and optical coherence tomography (OCT). RESULTS Of the 11 patients, the mean age was 52 years (range: 26-78). The mean age of ophthalmologic symptoms onset was 45 years (range: 15-72). The visual acuity varied from 20/20 to 20/80 (mean 20/30 median 20/20). We described five novel variants in HGSNAT: c.715del (p.Arg239Alafs *37), c.118 G>A (p.Asp40Asn), c.1218_1220delinsTAT, c.1297A>G (p.Asn433Asp), and c.1726 G>T (p.Gly576*). CONCLUSIONS HGSNAT has high phenotypic heterogeneity. Data from our cohort showed that all patients who had at least one variant of c.1843 G>A (p.Ala615Thr) presented with the onset of ocular symptoms after the fourth decade of life. The two patients with onset of ocular symptoms before the fourth decade did not carry this variant. This may suggest that c.1843 G>A variant is associated with a later onset of retinopathy.
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Affiliation(s)
- Mariana Matioli da Palma
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
- Department of Ophthalmology and Visual Sciences, Universidade Federal de São Paulo Escola Paulista de Medicina (UNIFESP), São Paulo, Brazil
- Instituto de Genética Ocular, São Paulo, Brazil
- Department of Surgery & Hospital Clinic of Barcelona, School of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Molly Marra
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Austin D Igelman
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Cristy A Ku
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, California, USA
| | - Amanda Burr
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Katherine Andersen
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Lesley A Everett
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | | | - Juliana Maria Ferraz Sallum
- Department of Ophthalmology and Visual Sciences, Universidade Federal de São Paulo Escola Paulista de Medicina (UNIFESP), São Paulo, Brazil
- Instituto de Genética Ocular, São Paulo, Brazil
| | - Paul Yang
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
| | - Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute at Oregon Health & Science University (OHSU), Portland, Oregon, USA
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Lalnunthangi A, Dakpa G, Tiwari S. Multifunctional role of the ubiquitin proteasome pathway in phagocytosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:179-217. [PMID: 36631192 DOI: 10.1016/bs.pmbts.2022.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Phagocytosis is a specialized form of endocytosis where large cells and particles (>0.5μm) are engulfed by the phagocytic cells, and ultimately digested in the phagolysosomes. This process not only eliminates unwanted particles and pathogens from the extracellular sources, but also eliminates apoptotic cells within the body, and is critical for maintenance of tissue homeostasis. It is believed that both endocytosis and phagocytosis share common pathways after particle internalization, but specialized features and differences between these two routes of internalization are also likely. The recruitment and removal of each protein/particle during the maturation of endocytic/phagocytic vesicles has to be tightly regulated to ensure their timely action. Ubiquitin proteasome pathway (UPP), degrades unwanted proteins by post-translational modification of proteins with chains of conserved protein Ubiquitin (Ub), with subsequent recognition of Ub chains by the 26S proteasomes and substrate degradation by this protease. This pathway utilizes different Ub linkages to modify proteins to regulate protein-protein interaction, localization, and activity. Due to its vast number of targets, it is involved in many cellular pathways, including phagocytosis. This chapters describes the basic steps and signaling in phagocytosis and different roles that UPP plays at multiple steps in regulating phagocytosis directly, or through its interaction with other phagosomal proteins. How aberrations in UPP function affect phagocytosis and their association with human diseases, and how pathogens exploit this pathway for their own benefit is also discussed.
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Affiliation(s)
| | | | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, India.
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Wang J, Wang Y, Jiang Y, Li X, Xiao X, Li S, Jia X, Sun W, Wang P, Zhang Q. Autosomal Dominant Retinitis Pigmentosa-Associated TOPORS Protein Truncating Variants Are Exclusively Located in the Region of Amino Acid Residues 807 to 867. Invest Ophthalmol Vis Sci 2022; 63:19. [PMID: 35579903 PMCID: PMC9123486 DOI: 10.1167/iovs.63.5.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Heterozygous truncating variants of TOPORS have been reported to cause autosomal dominant retinitis pigmentosa (adRP). The purpose of this study was to investigate whether all heterozygous truncating variants, including copy number variants (CNVs), are pathogenic. Methods TOPORS truncating variants were collected and reviewed through an in-house dataset and existing databases. Individuals with truncating variants underwent ophthalmological evaluation. Results Six truncating variants were detected in seven families. Three N-terminus truncating variants were detected in three families without RP, and the other three were identified in four unrelated families with typical RP. Based on the in-house dataset and published literature, 17 truncating variants were identified in 47 families with RP. All RP-associated truncating alleles, except one, were distributed in the last exon of TOPORS and clustered in amino acid residues 807 to 867 (46/47, 97.9%). Conversely, in the gnomAD database, only one truncating allele (1/27, 3.7%) was in this region, and the others were outside (26/27, 96.3%), suggesting that the pathogenic truncating variants were significantly clustered in residues 807 to 867 (χ2 = 65.6, P = 1.1 × 10–17). Additionally, three CNVs involving the N-terminus of TOPORS were recorded in control populations but were absent in affected patients. Conclusions This study suggests that all pathogenic truncating variants of TOPORS were clustered in residues 807 to 867, whereas the truncating variants outside this region and the CNVs involving the N-terminus were not associated with RP. A dominant-negative effect, rather than haploinsufficiency, is speculated to be the underlying pathogenesis. These findings provide valuable information for interpreting variation in TOPORS and other genes in similar situations, especially for CNVs.
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Affiliation(s)
- Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueqing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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He K, Zhou Y, Li N. Mutations of TOPORS identified in families with retinitis pigmentosa. Ophthalmic Genet 2022; 43:371-377. [PMID: 35254173 DOI: 10.1080/13816810.2022.2039721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Kaiwen He
- Department of Ophthalmology, Key Laboratory of Major Diseases in Children, Ministry of Education, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, China 100045
| | - Yunyu Zhou
- Department of Ophthalmology, Key Laboratory of Major Diseases in Children, Ministry of Education, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, China 100045
| | - Ningdong Li
- Department of Ophthalmology, Key Laboratory of Major Diseases in Children, Ministry of Education, Beijing Children’s Hospital, Capital Medical University, National Center for Children’s Health, China 100045
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Karali M, Testa F, Brunetti-Pierri R, Di Iorio V, Pizzo M, Melillo P, Barillari MR, Torella A, Musacchia F, D’Angelo L, Banfi S, Simonelli F. Clinical and Genetic Analysis of a European Cohort with Pericentral Retinitis Pigmentosa. Int J Mol Sci 2019; 21:ijms21010086. [PMID: 31877679 PMCID: PMC6982348 DOI: 10.3390/ijms21010086] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/12/2019] [Accepted: 12/19/2019] [Indexed: 12/28/2022] Open
Abstract
Retinitis pigmentosa (RP) is a clinically heterogenous disease that comprises a wide range of phenotypic and genetic subtypes. Pericentral RP is an atypical form of RP characterized by bone-spicule pigmentation and/or atrophy confined in the near mid-periphery of the retina. In contrast to classic RP, the far periphery is better preserved in pericentral RP. The aim of this study was to perform the first detailed clinical and genetic analysis of a cohort of European subjects with pericentral RP to determine the phenotypic features and the genetic bases of the disease. A total of 54 subjects from 48 independent families with pericentral RP, non-syndromic and syndromic, were evaluated through a full ophthalmological examination and underwent clinical exome or retinopathy gene panel sequencing. Disease-causative variants were identified in 22 of the 35 families (63%) in 10 different genes, four of which are also responsible for syndromic RP. Thirteen of the 34 likely pathogenic variants were novel. Intra-familiar variability was also observed. The current study confirms the mild phenotype of pericentral RP and extends the spectrum of genes associated with this condition.
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Affiliation(s)
- Marianthi Karali
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Luigi De Crecchio 7, 80138 Naples, Italy; (M.K.); (A.T.)
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Valentina Di Iorio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Mariateresa Pizzo
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
| | - Paolo Melillo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Maria Rosaria Barillari
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Annalaura Torella
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Luigi De Crecchio 7, 80138 Naples, Italy; (M.K.); (A.T.)
| | - Francesco Musacchia
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
| | - Luigi D’Angelo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Sandro Banfi
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Luigi De Crecchio 7, 80138 Naples, Italy; (M.K.); (A.T.)
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
- Correspondence: (S.B.); (F.S.); Tel.: +39-081-19230628 (S.B.); +39-081-7704501 (F.S.)
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
- Correspondence: (S.B.); (F.S.); Tel.: +39-081-19230628 (S.B.); +39-081-7704501 (F.S.)
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Comander J, Weigel-DiFranco C, Maher M, Place E, Wan A, Harper S, Sandberg MA, Navarro-Gomez D, Pierce EA. The Genetic Basis of Pericentral Retinitis Pigmentosa-A Form of Mild Retinitis Pigmentosa. Genes (Basel) 2017; 8:genes8100256. [PMID: 28981474 PMCID: PMC5664106 DOI: 10.3390/genes8100256] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/06/2017] [Accepted: 09/19/2017] [Indexed: 12/25/2022] Open
Abstract
Pericentral retinitis pigmentosa (RP) is an atypical form of RP that affects the near-peripheral retina first and tends to spare the far periphery. This study was performed to further define the genetic basis of this phenotype. We identified a cohort of 43 probands with pericentral RP based on a comprehensive analysis of their retinal phenotype. Genetic analyses of DNA samples from these patients were performed using panel-based next-generation sequencing, copy number variations, and whole exome sequencing (WES). Mutations provisionally responsible for disease were found in 19 of the 43 families (44%) analyzed. These include mutations in RHO (five patients), USH2A (four patients), and PDE6B (two patients). Of 28 putatively pathogenic alleles, 15 (54%) have been previously identified in patients with more common forms of typical RP, while the remaining 13 mutations (46%) were novel. Burden testing of WES data successfully identified HGSNAT as a cause of pericentral RP in at least two patients, suggesting it is also a relatively common cause of pericentral RP. While additional sequencing might uncover new genes specifically associated with pericentral RP, the current results suggest that genetically pericentral RP is not a separate clinical entity, but rather is part of the spectrum of mild RP phenotypes.
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Affiliation(s)
- Jason Comander
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Carol Weigel-DiFranco
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Matthew Maher
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Emily Place
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Aliete Wan
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Shyana Harper
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Michael A Sandberg
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Daniel Navarro-Gomez
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
| | - Eric A Pierce
- Ocular Genomics Institute, Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.
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Latasiewicz M, Salvetti AP, MacLaren RE. A novel mutation in the dominantly inherited TOPORS gene supports haploinsufficiency as the mechanism of retinitis pigmentosa. Ophthalmic Genet 2017; 38:562-566. [PMID: 28453362 DOI: 10.1080/13816810.2017.1313994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Inherited retinal degenerations are a major cause of untreatable blindness in the younger age group. Recent advances in gene therapy using adeno-associated viral (AAV) vectors have raised the possibility of slowing or stopping retinal degenerations with gene replacement in cases of gene deficiency. MATERIALS AND METHODS In this report, we present a family with autosomal dominant retinitis pigmentosa. A screen for common ADRP genes was performed with 105 genes targeted. Next generation sequencing was used to identify the mutation which was next confirmed by bidirectional Sanger sequencing. RESULTS A novel mutation of the TOPORS gene was identified, c.2539C>T p.(Arg847Ter), resulting in a premature termination codon and suggesting haploinsufficiency as the pathological mechanism. CONCLUSIONS Since the cDNA encoding TOPORS is 3,135 nucleotides (within the coding capacity of AAV vectors) and haploinsufficiency is a mechanism relating to inadequate gene expression, gene replacement therapy may be an option for patients with this condition.
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Affiliation(s)
- Marta Latasiewicz
- a Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Anna Paola Salvetti
- a Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK.,b Nuffield Laboratory of Ophthalmology, University of Oxford , Oxford , UK
| | - Robert E MacLaren
- a Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK.,b Nuffield Laboratory of Ophthalmology, University of Oxford , Oxford , UK
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TOPORS, a Dual E3 Ubiquitin and Sumo1 Ligase, Interacts with 26 S Protease Regulatory Subunit 4, Encoded by the PSMC1 Gene. PLoS One 2016; 11:e0148678. [PMID: 26872363 PMCID: PMC4752349 DOI: 10.1371/journal.pone.0148678] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 01/20/2016] [Indexed: 11/19/2022] Open
Abstract
The significance of the ubiquitin-proteasome system (UPS) for protein degradation has been highlighted in the context of neurodegenerative diseases, including retinal dystrophies. TOPORS, a dual E3 ubiquitin and SUMO1 ligase, forms a component of the UPS and selected substrates for its enzymatic activities, such as DJ-1/PARK7 and APOBEC2, are important for neuronal as well as retinal homeostasis, respectively. TOPORS is ubiquitously expressed, yet its mutations are only known to result in autosomal dominant retinitis pigmentosa. We performed a yeast two-hybrid (Y2H) screen of a human retinal cDNA library in order to identify interacting protein partners of TOPORS from the retina, and thus begin delineating the putative disease mechanism(s) associated with the retina-specific phenotype resulting from mutations in TOPORS. The screen led to isolation of the 26 S protease regulatory subunit 4 (P26s4/ PSMC1), an ATPase indispensable for correct functioning of UPS-mediated proteostasis. The interaction between endogenous TOPORS and P26s4 proteins was validated by co-immuno-precipitation from mammalian cell extracts and further characterised by immunofluorescent co-localisation studies in cell lines and retinal sections. Findings from hTERT-RPE1 and 661W cells demonstrated that TOPORS and P26s4 co-localise at the centrosome in cultured cells. Immunofluorescent staining of mouse retinae revealed a strong P26s4 reactivity at the interface between retinal pigmented epithelium (RPE) layer and the photoreceptors outer segments (OS). This finding leads us to speculate that P26s4, along with TOPORS, may have a role(s) in RPE phagocytosis, in addition to contributing to the overall photoreceptor and retinal homeostasis via the UPS.
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Matsui R, Cideciyan AV, Schwartz SB, Sumaroka A, Roman AJ, Swider M, Huang WC, Sheplock R, Jacobson SG. Molecular Heterogeneity Within the Clinical Diagnosis of Pericentral Retinal Degeneration. Invest Ophthalmol Vis Sci 2016; 56:6007-18. [PMID: 26393467 DOI: 10.1167/iovs.15-17174] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize in detail the phenotype and genotype of patients with pericentral retinal degeneration (PRD). METHODS Patients were screened for an annular ring scotoma ranging from 3° to 40° (n = 28, ages 24-71) with kinetic perimetry. All patients had pigmentary retinopathy in the region of the dysfunction. Further studies included cross-sectional and en face imaging, static chromatic perimetry, and electroretinography. Molecular screening was performed. RESULTS Genotypes of 14 of 28 PRD patients were identified: There were mutations in eight different genes previously associated with autosomal dominant or autosomal recessive RDs. Kinetic fields monitored in some patients over years to more than a decade could be stable or show increased extent of the scotoma. Electroretinograms were recordable but with different severities of dysfunction. Patterns of photoreceptor outer nuclear layer (ONL) loss corresponded to the distribution of visual dysfunction. Outer nuclear layer thickness topography and en face imaging indicated that the greatest disease expression was in the area of known highest rod photoreceptor density. CONCLUSIONS Molecular heterogeneity was a feature of the PRD phenotype. Many of the molecular causes were also associated with other phenotypes, such as maculopathies, typical retinitis pigmentosa (RP) and cone-rod dystrophy. The pericentral pattern of retinal degeneration is thus confirmed to be an uncommon phenotype of many different genotypes rather than a distinct disease entity.
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Weleber RG, Smith TB, Peters D, Chegarnov EN, Gillespie SP, Francis PJ, Gardiner SK, Paetzold J, Dietzsch J, Schiefer U, Johnson CA. VFMA: Topographic Analysis of Sensitivity Data From Full-Field Static Perimetry. Transl Vis Sci Technol 2015; 4:14. [PMID: 25938002 DOI: 10.1167/tvst.4.2.14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 11/16/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To analyze static visual field sensitivity with topographic models of the hill of vision (HOV), and to characterize several visual function indices derived from the HOV volume. METHODS A software application, Visual Field Modeling and Analysis (VFMA), was developed for static perimetry data visualization and analysis. Three-dimensional HOV models were generated for 16 healthy subjects and 82 retinitis pigmentosa patients. Volumetric visual function indices, which are measures of quantity and comparable regardless of perimeter test pattern, were investigated. Cross-validation, reliability, and cross-sectional analyses were performed to assess this methodology and compare the volumetric indices to conventional mean sensitivity and mean deviation. Floor effects were evaluated by computer simulation. RESULTS Cross-validation yielded an overall R2 of 0.68 and index of agreement of 0.89, which were consistent among subject groups, indicating good accuracy. Volumetric and conventional indices were comparable in terms of test-retest variability and discriminability among subject groups. Simulated floor effects did not negatively impact the repeatability of any index, but large floor changes altered the discriminability for regional volumetric indices. CONCLUSIONS VFMA is an effective tool for clinical and research analyses of static perimetry data. Topographic models of the HOV aid the visualization of field defects, and topographically derived indices quantify the magnitude and extent of visual field sensitivity. TRANSLATIONAL RELEVANCE VFMA assists with the interpretation of visual field data from any perimetric device and any test location pattern. Topographic models and volumetric indices are suitable for diagnosis, monitoring of field loss, patient counseling, and endpoints in therapeutic trials.
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Affiliation(s)
- Richard G Weleber
- Casey Eye Institute Oregon Retinal Degeneration Center, Oregon Health & Science University, Portland, OR, USA
| | - Travis B Smith
- Casey Eye Institute Oregon Retinal Degeneration Center, Oregon Health & Science University, Portland, OR, USA
| | - Dawn Peters
- Casey Eye Institute Oregon Retinal Degeneration Center, Oregon Health & Science University, Portland, OR, USA ; Department of Public Health and Preventative Medicine, Division of Biostatistics, Oregon Health & Science University, Portland, OR, USA
| | - Elvira N Chegarnov
- Casey Eye Institute Oregon Retinal Degeneration Center, Oregon Health & Science University, Portland, OR, USA
| | | | | | | | - Jens Paetzold
- Centre for Ophthalmology/Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Janko Dietzsch
- Centre for Ophthalmology/Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Ulrich Schiefer
- Centre for Ophthalmology/Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany ; Competence Centre "Vision Research", University of Applied Sciences, Aalen, Germany
| | - Chris A Johnson
- Department of Ophthalmology and Visual Sciences and the Institute for Vision Research, University of Iowa, Iowa City, IA, USA
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van Huet RAC, Siemiatkowska AM, Özgül RK, Yücel D, Hoyng CB, Banin E, Blumenfeld A, Rotenstreich Y, Riemslag FCC, den Hollander AI, Theelen T, Collin RWJ, van den Born LI, Klevering BJ. Retinitis pigmentosa caused by mutations in the ciliary MAK gene is relatively mild and is not associated with apparent extra-ocular features. Acta Ophthalmol 2015; 93:83-94. [PMID: 25385675 DOI: 10.1111/aos.12500] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/17/2014] [Indexed: 12/13/2022]
Abstract
PURPOSE Defects in MAK, encoding a protein localized to the photoreceptor connecting cilium, have recently been associated with autosomal recessive retinitis pigmentosa (RP). The aim of this study is to describe our detailed clinical observations in patients with MAK-associated RP, including an assessment of syndromic symptoms frequently observed in ciliopathies. METHODS In this international collaborative study, 11 patients carrying nonsense or missense mutations in MAK were clinically evaluated, including extensive assessment of the medical history, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence imaging and fundus photography. Additionally, we used a questionnaire to evaluate the presence of syndromic features and tested the olfactory function. RESULTS MAK-associated RP is not associated with syndromic features, not even with subclinical dysfunction of the olfactory apparatus. All patients experienced typical RP symptoms of night blindness followed by visual field constriction. Symptoms initiated between childhood and the age of 43 (mean: 23 years). Although some patients experienced vision loss, the visual acuity remained normal in most patients. ERG and ophthalmoscopy revealed classic RP characteristics, and SD-OCT demonstrated thinning of the overall retina, outer nuclear layer and photoreceptor-pigment epithelium complex. CONCLUSION Nonsense and missense mutations in MAK give rise to a non-syndromic recessive RP phenotype without apparent extra-ocular features. When compared to other retinal ciliopathies, MAK-associated RP appears to be relatively mild and shows remarkable resemblance to RP1-associated RP, which could be explained by the close functional relation of these proteins.
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Affiliation(s)
- Ramon A. C. van Huet
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
| | - Anna M. Siemiatkowska
- Department of Human Genetics; Radboud University Medical Center; Nijmegen The Netherlands
| | - Riza K. Özgül
- Institute of Child Health and Metabolism Unit; Department of Pediatrics; Hacettepe University; Ankara Turkey
| | - Didem Yücel
- Institute of Child Health and Metabolism Unit; Department of Pediatrics; Hacettepe University; Ankara Turkey
| | - Carel B. Hoyng
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
| | - Eyal Banin
- Department of Ophthalmology; Hadassah-Hebrew University Medical Center; Jerusalem Israel
| | - Anat Blumenfeld
- Department of Ophthalmology; Hadassah-Hebrew University Medical Center; Jerusalem Israel
| | - Ygal Rotenstreich
- Electrophysiology Clinic; Goldschleger Eye Research Institute; Tel Aviv University; Sheba Medical Centre; Ramat Gan Israel
| | - Frans C. C. Riemslag
- The Rotterdam Eye Hospital; Rotterdam The Netherlands
- Bartiméus, Institute for the Visually Handicapped; Zeist The Netherlands
| | - Anneke I. den Hollander
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
- Department of Human Genetics; Radboud University Medical Center; Nijmegen The Netherlands
- Nijmegen Center for Molecular Life Sciences; Radboud University Medical Center; Nijmegen The Netherlands
| | - Thomas Theelen
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
| | - Rob W. J. Collin
- Department of Human Genetics; Radboud University Medical Center; Nijmegen The Netherlands
- Nijmegen Center for Molecular Life Sciences; Radboud University Medical Center; Nijmegen The Netherlands
| | | | - B. Jeroen Klevering
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
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Xiang F, Yah M, Song G, Zheng F. Gene mapping and mutation screeneng in candidate genes in a Chinese family of autosomal dominant retinitis pigmentosa. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412010188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Chakarova CF, Khanna H, Shah AZ, Patil SB, Sedmak T, Murga-Zamalloa CA, Papaioannou MG, Nagel-Wolfrum K, Lopez I, Munro P, Cheetham M, Koenekoop RK, Rios RM, Matter K, Wolfrum U, Swaroop A, Bhattacharya SS. TOPORS, implicated in retinal degeneration, is a cilia-centrosomal protein. Hum Mol Genet 2010; 20:975-87. [PMID: 21159800 DOI: 10.1093/hmg/ddq543] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We recently reported that mutations in the widely expressed nuclear protein TOPORS (topoisomerase I-binding arginine/serine rich) are associated with autosomal dominant retinal degeneration. However, the precise localization and a functional role of TOPORS in the retina remain unknown. Here, we demonstrate that TOPORS is a novel component of the photoreceptor sensory cilium, which is a modified primary cilium involved with polarized trafficking of proteins. In photoreceptors, TOPORS localizes primarily to the basal bodies of connecting cilium and in the centrosomes of cultured cells. Morpholino-mediated silencing of topors in zebrafish embryos demonstrates in another species a comparable retinal problem as seen in humans, resulting in defective retinal development and failure to form outer segments. These defects can be rescued by mRNA encoding human TOPORS. Taken together, our data suggest that TOPORS may play a key role in regulating primary cilia-dependent photoreceptor development and function. Additionally, it is well known that mutations in other ciliary proteins cause retinal degeneration, which may explain why mutations in TOPORS result in the same phenotype.
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