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Ayyagari R, Borooah S, Durham T, Gelfman C, Bowman A. Current and Future Directions in Developing Effective Treatments for PRPH2-Associated Retinal Diseases: A Workshop Report. Transl Vis Sci Technol 2024; 13:16. [PMID: 39382871 DOI: 10.1167/tvst.13.10.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2024] Open
Abstract
Purpose and Methods A workshop of affected individuals and their families, clinicians, researchers, and industry representatives was convened in March 2023 to define the knowledge landscape of peripherin 2 (PRPH2) biology and identify challenges and opportunities towards developing PRPH2-associated inherited retinal disease (IRD) treatments. Results The results of an online survey and presentations from affected individuals and their family members revealed disease characteristics and impacts on daily living. Scientific sessions highlighted the significant heterogeneity in clinical presentation of PRPH2-related retinopathy; PRPH2's crucial function in rod and cone outer segment formation and maintenance; the usefulness of existing animal and cellular models for understanding disease pathophysiology; and possible therapeutic approaches for autosomal dominant PRPH2-associated IRDs, including gene-specific therapies and gene-agnostic approaches. Priority gaps identified by the workshop included having a more complete understanding of PRPH2's fundamental biology and factors contributing to PRPH2-related disease phenotypic diversity, establishing genotype-phenotype correlations, and creating additional models to probe the functional consequences of PRPH2 variants and to test therapies. Additionally, a natural history study involving a large number of participants is required to more fully characterize PRPH2-related disease progression, aiding in interventional clinical trial design. Conclusions Because PRPH2-associated IRDs are rare, maximizing opportunities for communication and collaboration among stakeholders, such as that provided by the workshop, is crucial to overcome the challenges to developing effective treatments and improve the lives of affected individuals. Translational Relevance Fostering communication among stakeholders to identify knowledge gaps, therapeutic challenges, and potential opportunities toward developing effective treatments for PRPH2-related IRDs.
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Affiliation(s)
- Radha Ayyagari
- Shiley Eye Institute, University of California, San Diego, CA, USA
| | | | - Todd Durham
- Foundation Fighting Blindness, Columbia, MD, USA
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2
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Rutan Woods CT, Makia MS, Lewis TR, Crane R, Zeibak S, Yu P, Kakakhel M, Castillo CM, Arshavsky VY, Naash MI, Al-Ubaidi MR. Downregulation of rhodopsin is an effective therapeutic strategy in ameliorating peripherin-2-associated inherited retinal disorders. Nat Commun 2024; 15:4756. [PMID: 38834544 PMCID: PMC11150396 DOI: 10.1038/s41467-024-48846-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 05/15/2024] [Indexed: 06/06/2024] Open
Abstract
Given the absence of approved treatments for pathogenic variants in Peripherin-2 (PRPH2), it is imperative to identify a universally effective therapeutic target for PRPH2 pathogenic variants. To test the hypothesis that formation of the elongated discs in presence of PRPH2 pathogenic variants is due to the presence of the full complement of rhodopsin in absence of the required amounts of functional PRPH2. Here we demonstrate the therapeutic potential of reducing rhodopsin levels in ameliorating disease phenotype in knockin models for p.Lys154del (c.458-460del) and p.Tyr141Cys (c.422 A > G) in PRPH2. Reducing rhodopsin levels improves physiological function, mitigates the severity of disc abnormalities, and decreases retinal gliosis. Additionally, intravitreal injections of a rhodopsin-specific antisense oligonucleotide successfully enhance the physiological function of photoreceptors and improves the ultrastructure of discs in mutant mice. Presented findings shows that reducing rhodopsin levels is an effective therapeutic strategy for the treatment of inherited retinal degeneration associated with PRPH2 pathogenic variants.
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Affiliation(s)
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Ryan Crane
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Stephanie Zeibak
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Paul Yu
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA.
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3
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Heath Jeffery RC, Chen FK. Macular neovascularization in inherited retinal diseases: A review. Surv Ophthalmol 2024; 69:1-23. [PMID: 37544613 DOI: 10.1016/j.survophthal.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023]
Abstract
Inherited retinal diseases (IRDs) are the most common cause of blindness in working-age adults. Macular neovascularization (MNV) may be a presenting feature or occurs as a late-stage complication in several IRDs. We performed an extensive literature review on MNV associated with IRDs. MNV is a well-known complication of Sorsby fundus dystrophy and pseudoxanthoma elasticum. Those with late-onset Stargardt disease may masquerade as exudative age-related macular degeneration (AMD) when MNV is the presenting feature. Peripherinopathies may develop MNV that responds well to a short course of anti-vascular endothelial growth factor (anti-VEGF) therapy, while bestrophinopathies tend to develop MNV in the early stages of the disease without vision loss. Enhanced S-cone syndrome manifests type 3 MNV that typically regresses into a subfoveal fibrotic nodule. MNV is only a rare complication in choroideraemia and rod-cone dystrophies. Most IRD-related MNVs exhibit a favorable visual prognosis requiring less intensive regimens of anti-vascular endothelial growth factor therapy compared to age-related macular degeneration. We discuss the role of key imaging modalities in the diagnosis of MNV across a wide spectrum of IRDs and highlight the gaps in our knowledge with respect to the natural history and prognosis to pave the way for future directions of research.
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Affiliation(s)
- Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia; Royal Victorian Eye and Ear Hospital (Centre for Eye Research Australia), East Melbourne, VIC, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (Lions Eye Institute), The University of Western Australia, Nedlands, WA, Australia; Royal Victorian Eye and Ear Hospital (Centre for Eye Research Australia), East Melbourne, VIC, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, East Melbourne, VIC, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, WA, Australia.
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4
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Ikelle L, Makia M, Lewis T, Crane R, Kakakhel M, Conley SM, Birtley JR, Arshavsky VY, Al-Ubaidi MR, Naash MI. Comparative study of PRPH2 D2 loop mutants reveals divergent disease mechanism in rods and cones. Cell Mol Life Sci 2023; 80:214. [PMID: 37466729 PMCID: PMC10356684 DOI: 10.1007/s00018-023-04851-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/10/2023] [Accepted: 06/28/2023] [Indexed: 07/20/2023]
Abstract
Mutations in the photoreceptor-specific tetraspanin gene peripherin-2 (PRPH2) lead to widely varying forms of retinal degeneration ranging from retinitis pigmentosa to macular dystrophy. Both inter- and intra-familial phenotypic heterogeneity has led to much interest in uncovering the complex pathogenic mechanisms of PRPH2-associated disease. Majority of disease-causing mutations in PRPH2 reside in the second intradiscal loop, wherein seven cysteines control protein folding and oligomerization. Here, we utilize knockin models to evaluate the role of three D2 loop cysteine mutants (Y141C, C213Y and C150S), alone or in combination. We elucidated how these mutations affect PRPH2 properties, including oligomerization and subcellular localization, and contribute to disease processes. Results from our structural, functional and molecular studies revealed that, in contrast to our understanding from prior investigations, rods are highly affected by PRPH2 mutations interfering with oligomerization and not merely by the haploinsufficiency associated with these mutations. On the other hand, cones are less affected by the toxicity of the mutant protein and significantly reduced protein levels, suggesting that knockdown therapeutic strategies may sustain cone functionality for a longer period. This observation provides useful data to guide and simplify the current development of effective therapeutic approaches for PRPH2-associated diseases that combine knockdown with high levels of gene supplementation needed to generate prolonged rod improvement.
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Affiliation(s)
- Larissa Ikelle
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Mustafa Makia
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Tylor Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Ryan Crane
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | | | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA.
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, 3517 Cullen Blvd. Room 2027, Houston, TX, 77204-5060, USA.
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5
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Makuloluwa A, Madhusudhan S. Clinical outcomes of treated macular neovascularisation secondary to inherited retinal diseases: a literature review. BMJ Open Ophthalmol 2023; 8:e001309. [PMID: 37493670 PMCID: PMC10364169 DOI: 10.1136/bmjophth-2023-001309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/10/2023] [Indexed: 07/27/2023] Open
Abstract
Many inherited retinal diseases (IRD) can be associated with, or be secondarily complicated by, macular neovascularisation (MNV), which has been variably treated with intravitreal antivascular endothelial growth factor, steroids, laser and surgery. In this article, we aim to present a consolidated literature review of management of IRD-related MNV.
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Affiliation(s)
- Aruni Makuloluwa
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
| | - Savita Madhusudhan
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK
- Department of Eye and Vision Science, University of Liverpool, Liverpool, UK
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6
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Chiang TK, Yu M. Electrophysiological Evaluation of Macular Dystrophies. J Clin Med 2023; 12:jcm12041430. [PMID: 36835965 PMCID: PMC9962076 DOI: 10.3390/jcm12041430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023] Open
Abstract
Macular dystrophies are a heterogeneous group of genetic disorders that often severely threatens the bilateral central vision of the affected patient. While advances in molecular genetics have been instrumental in the understanding and diagnosis of these disorders, there remains significant phenotypical variation among patients within any particular subset of macular dystrophies. Electrophysiological testing remains a vital tool not only to characterize vision loss for differential diagnosis but also to understand the pathophysiology of these disorders and to monitor the treatment effect, potentially leading to therapeutic advances. This review summarizes the application of electrophysiological testing in macular dystrophies, including Stargardt disease, bestrophinopathies, X-linked retinoschisis, Sorsby fundus dystrophy, Doyne honeycomb retina dystrophy, autosomal dominant drusen, occult macular dystrophy, North Carolina macular dystrophy, pattern dystrophy, and central areolar choroidal dystrophy.
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Antonelli G, Parravano M, Barbano L, Costanzo E, Bertelli M, Medori MC, Parisi V, Ziccardi L. Multimodal Study of PRPH2 Gene-Related Retinal Phenotypes. Diagnostics (Basel) 2022; 12:diagnostics12081851. [PMID: 36010202 PMCID: PMC9406607 DOI: 10.3390/diagnostics12081851] [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] [Received: 07/06/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 11/25/2022] Open
Abstract
PRPH2 gene mutations are frequently found in inherited retinal dystrophies (IRD) and are associated with a wide spectrum of clinical phenotypes. We studied 28 subjects affected by IRD carrying pathogenic PRPH2 mutations, belonging to 11 unrelated families. Functional tests (best-corrected visual acuity measurement, chromatic test, visual field, full-field, 30 Hz flicker, and multifocal electroretinogram), morphological retino-choroidal imaging (optical coherence tomography, optical coherence tomography angiography, and fundus autofluorescence), and clinical data were collected and analyzed. Common primary complaints, with onset in their 40s, were visual acuity reduction and abnormal dark adaptation. Visual acuity ranged from light perception to 20/20 Snellen. Visual field peripheral constriction and central scotoma were found. Chromatic sense was reduced in one third of patients. Electrophysiological tests were abnormal in most of the patients. Choroidal neovascular lesions were detected in five patients. Three novel PRPH2 variants were found in four different families. Based on the present multimodal study, we identified seven distinct PRPH2 phenotypes in 11 unrelated families carrying either different mutations or the same mutation, both within the same family or among them. Fundus autofluorescence modality turned out to be the most adequate imaging method for early recognition of this dystrophy, and the optical coherence tomography angiography was highly informative to promptly detect choroidal neovascularization, even in the presence of the extensive chorioretinal atrophy phenotype.
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Affiliation(s)
- Giulio Antonelli
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Mariacristina Parravano
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
- Correspondence: ; Tel.: +39-067-705-2963
| | - Lucilla Barbano
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Eliana Costanzo
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Matteo Bertelli
- MAGI’S LAB, Via Delle Maioliche 57/D, 38068 Rovereto, Italy; (M.B.); (M.C.M.)
- MAGI EUREGIO, Via Maso Delle Pieve 60/A, 39100 Bolzano, Italy
- MAGISNAT, Atlanta Tech Park, 107 Technology, Parkway, Peachtree Corners, GA 30092, USA
| | - Maria Chiara Medori
- MAGI’S LAB, Via Delle Maioliche 57/D, 38068 Rovereto, Italy; (M.B.); (M.C.M.)
| | - Vincenzo Parisi
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
| | - Lucia Ziccardi
- IRCCS—Fondazione Bietti, Via Livenza 3, 00198 Rome, Italy; (G.A.); (L.B.); (E.C.); (V.P.); (L.Z.)
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8
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Modulation of SOD3 Levels Is Detrimental to Retinal Homeostasis. Antioxidants (Basel) 2021; 10:antiox10101595. [PMID: 34679728 PMCID: PMC8533566 DOI: 10.3390/antiox10101595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/05/2021] [Accepted: 10/07/2021] [Indexed: 01/08/2023] Open
Abstract
Retinal oxidative stress is a common secondary feature of many retinal diseases. Though it may not be the initial insult, it is a major contributor to the pathogenesis of highly prevalent retinal dystrophic diseases like macular degeneration, diabetic retinopathy, and retinitis pigmentosa. We explored the role of superoxide dismutase 3 (SOD3) in retinal homeostasis since SOD3 protects the extracellular matrix (ECM) from oxidative injury. We show that SOD3 is mainly extracellularly localized and is upregulated as a result of environmental and pathogenic stress. Ablation of SOD3 resulted in reduced functional electroretinographic responses and number of photoreceptors, which is exacerbated with age. By contrast, overexpression showed increased electroretinographic responses and increased number of photoreceptors at young ages, but appears deleterious as the animal ages, as determined from the associated functional decline. Our exploration shows that SOD3 is vital to retinal homeostasis but its levels are tightly regulated. This suggests that SOD3 augmentation to combat oxidative stress during retinal degenerative changes may only be effective in the short-term.
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9
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Peeters MHCA, Khan M, Rooijakkers AAMB, Mulders T, Haer-Wigman L, Boon CJF, Klaver CCW, van den Born LI, Hoyng CB, Cremers FPM, den Hollander AI, Dhaenens CM, Collin RWJ. PRPH2 mutation update: In silico assessment of 245 reported and 7 novel variants in patients with retinal disease. Hum Mutat 2021; 42:1521-1547. [PMID: 34411390 PMCID: PMC9290825 DOI: 10.1002/humu.24275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/22/2021] [Accepted: 08/16/2021] [Indexed: 01/31/2023]
Abstract
Mutations in PRPH2, encoding peripherin-2, are associated with the development of a wide variety of inherited retinal diseases (IRDs). To determine the causality of the many PRPH2 variants that have been discovered over the last decades, we surveyed all published PRPH2 variants up to July 2020, describing 720 index patients that in total carried 245 unique variants. In addition, we identified seven novel PRPH2 variants in eight additional index patients. The pathogenicity of all variants was determined using the ACMG guidelines. With this, 107 variants were classified as pathogenic, 92 as likely pathogenic, one as benign, and two as likely benign. The remaining 50 variants were classified as variants of uncertain significance. Interestingly, of the total 252 PRPH2 variants, more than half (n = 137) were missense variants. All variants were uploaded into the Leiden Open source Variation and ClinVar databases. Our study underscores the need for experimental assays for variants of unknown significance to improve pathogenicity classification, which would allow us to better understand genotype-phenotype correlations, and in the long-term, hopefully also support the development of therapeutic strategies for patients with PRPH2-associated IRD.
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Affiliation(s)
- Manon H C A Peeters
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | | | - Timo Mulders
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, Amsterdam, The Netherlands
| | - Caroline C W Klaver
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Ophthalmology, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - L Ingeborgh van den Born
- The Rotterdam Eye Hospital, Rotterdam, The Netherlands.,Rotterdam Ophthalmic Institute, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claire-Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Biochemistry and Molecular Biology, Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, Lille, France
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Human Genetics and Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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10
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Sodi A, Mucciolo DP, Giorgio D, Passerini I, Pacini B, Bruschi M, Verdina T, Virgili G, Giansanti F, Murro V. Clinical and molecular findings in patients with pattern dystrophy. Ophthalmic Genet 2021; 42:577-587. [PMID: 34240658 DOI: 10.1080/13816810.2021.1938140] [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: 10/20/2022]
Abstract
Purposes: To study the clinical and genetic background of a series of Italian patients affected by pattern dystrophy (PD).Methods: We reviewed patients with a clinical diagnosis of PD examined at the Eye Clinic in Florence from 2012 to 2019. We took into consideration patients with a standard ophthalmological examination, personal and familial ophthalmological history, fundus imaging, and molecular genetic analysis of genes PRPH2 and BEST1. We labelled patients with BEST1 and PRPH2 mutations as m-PD group (mutated) whereas patients with no mutations in these 2 genes as nm-PD group (non-mutated).Results: Seventy-seven PD patients were assessed (average age 59.7 ± 14.2, range 31-88 years). Fifty patients were placed in the nm-PD group and 27 in the m-PD. Pathogenic BEST1 and PRPH2 mutations were detected in 7% and 22% of PD patients, respectively. In total, we reported 1 BEST1 and 8 PRPH2 novel mutations. Ten patients were characterized by drusen in the nm-PD group whereas in no patients in the m-PD group drusen were detected at the fundus.Conclusions: An important proportion of patients affected by PD showed BEST1 or PRPH2 mutations. Patients affected by drusen represent a different sub-phenotype. Genetic examination is recommended for a correct clinical management.
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Affiliation(s)
- Andrea Sodi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy.,Ophthalmology Unit, San Jacopo Hospital, Pistoia, Italy
| | - Dario Giorgio
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Ilaria Passerini
- Department of Genetic Diagnosis, Careggi Teaching Hospital, Florence, Italy
| | - Bianca Pacini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Mario Bruschi
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Tommaso Verdina
- Institute of Ophthalmology, University of Modena and Reggio Emilia, Modena, Italy
| | - Gianni Virgili
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy.,IRCCS Fondazione G. B. Bietti, Roma, Italy
| | - Fabrizio Giansanti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
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11
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Absence of Genotype/Phenotype Correlations Requires Molecular Diagnostic to Ascertain Stargardt and Stargardt-Like Swiss Patients. Genes (Basel) 2021; 12:genes12060812. [PMID: 34073554 PMCID: PMC8229718 DOI: 10.3390/genes12060812] [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: 05/04/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
We genetically characterized 22 Swiss patients who had been diagnosed with Stargardt disease after clinical examination. We identified in 11 patients (50%) pathogenic bi-allelic ABCA4 variants, c.1760+2T>C and c.4496T>C being novel. The dominantly inherited pathogenic ELOVL4 c.810C>G p.(Tyr270*) and PRPH2-c.422A>G p.(Tyr141Cys) variants were identified in eight (36%) and three patients (14%), respectively. All patients harboring the ELOVL4 c.810C>G p.(Tyr270*) variant originated from the same small Swiss area, identifying a founder mutation. In the ABCA4 and ELOVL4 cohorts, the clinical phenotypes of “flecks”, “atrophy”, and “bull’s eye like” were observed by fundus examination. In the small number of patients harboring the pathogenic PRPH2 variant, we could observe both “flecks” and “atrophy” clinical phenotypes. The onset of disease, progression of visual acuity and clinical symptoms, inheritance patterns, fundus autofluorescence, and optical coherence tomography did not allow discrimination between the genetically heterogeneous Stargardt patients. The genetic heterogeneity observed in the relatively small Swiss population should prompt systematic genetic testing of clinically diagnosed Stargardt patients. The resulting molecular diagnostic is required to prevent potentially harmful vitamin A supplementation, to provide genetic counseling with respect to inheritance, and to schedule appropriate follow-up visits in the presence of increased risk of choroidal neovascularization.
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12
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Lewis TR, Makia MS, Castillo CM, Al-Ubaidi MR, Naash MI, Arshavsky VY. Photoreceptor Disc Enclosure Is Tightly Controlled by Peripherin-2 Oligomerization. J Neurosci 2021; 41:3588-3596. [PMID: 33707293 PMCID: PMC8055076 DOI: 10.1523/jneurosci.0041-21.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/15/2021] [Accepted: 03/05/2021] [Indexed: 11/21/2022] Open
Abstract
Mutations in the PRPH2 gene encoding the photoreceptor-specific protein PRPH2 (also known as peripherin-2 or rds) cause a broad range of autosomal dominant retinal diseases. Most of these mutations affect the structure of the light-sensitive photoreceptor outer segment, which is composed of a stack of flattened "disc" membranes surrounded by the plasma membrane. The outer segment is renewed on a daily basis in a process whereby new discs are added at the outer segment base and old discs are shed at the outer segment tip. New discs are formed as serial membrane evaginations, which eventually enclose through a complex process of membrane remodeling (completely in rods and partially in cones). As disc enclosure proceeds, PRPH2 localizes to the rims of enclosed discs where it forms oligomers which fortify the highly curved membrane structure of these rims. In this study, we analyzed the outer segment phenotypes of mice of both sexes bearing a single copy of either the C150S or the Y141C PRPH2 mutation known to prevent or increase the degree of PRPH2 oligomerization, respectively. Strikingly, both mutations increased the number of newly forming, not-yet-enclosed discs, indicating that the precision of disc enclosure is regulated by PRPH2 oligomerization. Without tightly controlled enclosure, discs occasionally over-elongate and form large membranous "whorls" instead of disc stacks. These data show that the defects in outer segment structure arising from abnormal PRPH2 oligomerization are manifested at the stage of disc enclosure.SIGNIFICANCE STATEMENT The light-sensitive photoreceptor outer segment contains a stack of flattened "disc" membranes that are surrounded, or "enclosed," by the outer segment membrane. Disc enclosure is an adaptation increasing photoreceptor light sensitivity by facilitating the diffusion of the second messenger along the outer segment axes. However, the molecular mechanisms by which photoreceptor discs enclose within the outer segment membrane remain poorly understood. We now demonstrate that oligomers of the photoreceptor-specific protein peripherin-2, or PRPH2, play an active role in this process. We further propose that defects in disc enclosure because of abnormal PRPH2 oligomerization result in major structural abnormalities of the outer segment, ultimately leading to loss of visual function and cell degeneration in PRPH2 mutant models and human patients.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
| | - Carson M Castillo
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, Texas 77204
- College of Optometry, University of Houston, Houston, Texas 77204
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
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13
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Genc AM, Makia MS, Sinha T, Conley SM, Al-Ubaidi MR, Naash MI. Retbindin: A riboflavin Binding Protein, Is Critical for Photoreceptor Homeostasis and Survival in Models of Retinal Degeneration. Int J Mol Sci 2020; 21:ijms21218083. [PMID: 33138244 PMCID: PMC7662319 DOI: 10.3390/ijms21218083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Abstract
The large number of inherited retinal disease genes (IRD), including the photopigment rhodopsin and the photoreceptor outer segment (OS) structural component peripherin 2 (PRPH2), has prompted interest in identifying common cellular mechanisms involved in degeneration. Although metabolic dysregulation has been shown to play an important role in the progression of the disease etiology, identifying a common regulator that can preserve the metabolic ecosystem is needed for future development of neuroprotective treatments. Here, we investigated whether retbindin (RTBDN), a rod-specific protein with riboflavin binding capability, and a regulator of riboflavin-derived cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), is protective to the retina in different IRD models; one carrying the P23H mutation in rhodopsin (which causes retinitis pigmentosa) and one carrying the Y141C mutation in Prph2 (which causes a blended cone-rod dystrophy). RTBDN levels are significantly upregulated in both the rhodopsin (Rho)P23H/+ and Prph2Y141C/+ retinas. Rod and cone structural and functional degeneration worsened in models lacking RTBDN. In addition, removing Rtbdn worsened other phenotypes, such as fundus flecking. Retinal flavin levels were reduced in RhoP23H/+/Rtbdn−/− and Prph2Y141C/+/Rtbdn−/− retinas. Overall, these findings suggest that RTBDN may play a protective role during retinal degenerations that occur at varying rates and due to varying disease mechanisms.
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Affiliation(s)
- Ayse M. Genc
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (A.M.G.); (M.S.M.); (T.S.)
| | - Mustafa S. Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (A.M.G.); (M.S.M.); (T.S.)
| | - Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (A.M.G.); (M.S.M.); (T.S.)
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (A.M.G.); (M.S.M.); (T.S.)
- College of Optometry, University of Houston, Houston, TX 77204, USA
- Department of Biology and Biochemistry, University of Houston, TX 77204, USA
- Correspondence: (M.R.A.-U.); (M.I.N.); Tel.: +1-713-743-1651 (M.R.A.-U. & M.I.N.); Fax: +1-713-743-0226 (M.R.A.-U. & M.I.N.)
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA; (A.M.G.); (M.S.M.); (T.S.)
- College of Optometry, University of Houston, Houston, TX 77204, USA
- Department of Biology and Biochemistry, University of Houston, TX 77204, USA
- Correspondence: (M.R.A.-U.); (M.I.N.); Tel.: +1-713-743-1651 (M.R.A.-U. & M.I.N.); Fax: +1-713-743-0226 (M.R.A.-U. & M.I.N.)
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14
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Strayve D, Makia MS, Kakakhel M, Sakthivel H, Conley SM, Al-Ubaidi MR, Naash MI. ROM1 contributes to phenotypic heterogeneity in PRPH2-associated retinal disease. Hum Mol Genet 2020; 29:2708-2722. [PMID: 32716032 DOI: 10.1093/hmg/ddaa160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/03/2020] [Accepted: 07/16/2020] [Indexed: 11/14/2022] Open
Abstract
Peripherin 2 (PRPH2) is a retina-specific tetraspanin protein essential for the formation of rod and cone photoreceptor outer segments (OS). Patients with mutations in PRPH2 exhibit severe retinal degeneration characterized by vast inter- and intra-familial phenotypic heterogeneity. To help understand contributors to this within-mutation disease variability, we asked whether the PRPH2 binding partner rod OS membrane protein 1 (ROM1) could serve as a phenotypic modifier. We utilized knockin and transgenic mouse models to evaluate the structural, functional and biochemical effects of eliminating one allele of Rom1 (Rom1+/-) in three different Prph2 models which mimic human disease: C213Y Prph2 (Prph2C/+), K153Del Prph2 (Prph2K/+) and R172W (Prph2R172W). Reducing Rom1 in the absence of Prph2 mutations (Rom1+/-) had no effect on retinal structure or function. However, the effects of reducing Rom1 in the presence of Prph2 mutations were highly variable. Prph2K/+/Rom1+/- mice had improved rod and cone function compared with Prph2K/+ as well as amelioration of K153Del-associated defects in PRPH2/ROM1 oligomerization. In contrast, Prph2R172W/Rom1+/- animals had worsened rod and cone function and exacerbated retinal degeneration compared with Prph2R172W animals. Removing one allele of Rom1 had no effect in Prph2C/+. Combined, our findings support a role for non-pathogenic ROM1 null variants in contributing to phenotypic variability in mutant PRPH2-associated retinal degeneration. Since the effects of Rom1 reduction are variable, our data suggest that this contribution is specific to the type of Prph2 mutation.
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Affiliation(s)
- Daniel Strayve
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Haarthi Sakthivel
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.,Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.,College of Optometry, University of Houston, Houston, TX 77004, USA.,Depatment of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA.,College of Optometry, University of Houston, Houston, TX 77004, USA.,Depatment of Biology and Biochemistry, University of Houston, Houston, TX 77204-5001, USA
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15
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Lee CS, Leys M. A Family Affected by Novel C213W Mutation in
PRPH2
: Long-Term Follow-Up of CNV Secondary to Pattern Dystrophy. Ophthalmic Surg Lasers Imaging Retina 2020; 51:354-362. [DOI: 10.3928/23258160-20200603-06] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/04/2020] [Indexed: 12/11/2022]
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16
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Parodi MB, Iacono P, Da Pozzo S. Anti-VEGF and Retinal Dystrophies. Curr Drug Targets 2020; 21:1201-1207. [PMID: 32342816 DOI: 10.2174/1389450121666200428103334] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 02/19/2020] [Accepted: 03/02/2020] [Indexed: 11/22/2022]
Abstract
The therapeutic approach based on anti-vascular endothelial growth factor (anti-VEGF) molecules can be used to treat two important complications of retinal dystrophies: choroidal neovascularization and macular edema. The macular involvement in retinal dystrophies can lead to further visual deterioration in patients at a young age and already affected by functional limitations. The study reports the effect of anti-VEGF treatment in several subforms of retinal dystrophies, critically discussing advantages and limitations.
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17
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Lewis TR, Makia MS, Kakakhel M, Al-Ubaidi MR, Arshavsky VY, Naash MI. Photoreceptor Disc Enclosure Occurs in the Absence of Normal Peripherin-2/rds Oligomerization. Front Cell Neurosci 2020; 14:92. [PMID: 32410962 PMCID: PMC7198881 DOI: 10.3389/fncel.2020.00092] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in the peripherin-2 gene (PRPH2, also known as rds) cause a heterogeneous range of autosomal dominant retinal diseases. PRPH2 encodes a photoreceptor-specific tetraspanin protein, PRPH2, that is a main structural component of the photoreceptor outer segment. PRPH2 distributes to the rims of outer segment disc membranes as they undergo the process of disc membrane enclosure. Within these rims, PRPH2 exists in homo-oligomeric form or as a hetero-oligomer with another tetraspanin protein, ROM1. While complete loss of PRPH2 prevents photoreceptor outer segment formation, mutations affecting the state of its oligomerization, including C150S, C213Y and Y141C, produce outer segment structural defects. In this study, we addressed whether any of these mutations also affect disc enclosure. We employed recently developed methodology for ultrastructural analysis of the retina, involving tissue processing with tannic acid, to assess the status of disc enclosure in knockin mouse models bearing either one or two alleles of the C150S, C213Y and Y141C PRPH2 mutations. While varying degrees of outer segment structural abnormalities were observed in each of these mouse models, they contained both newly forming “open” discs and mature “enclosed” discs. These data demonstrate that normal PRPH2 oligomerization is not essential for photoreceptor disc enclosure.
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Affiliation(s)
- Tylor R Lewis
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, United States
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Mashal Kakakhel
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States.,College of Optometry, University of Houston, Houston, TX, United States
| | - Vadim Y Arshavsky
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, United States.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, United States
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States.,College of Optometry, University of Houston, Houston, TX, United States
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18
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Rodríguez-Muñoz A, Aller E, Jaijo T, González-García E, Cabrera-Peset A, Gallego-Pinazo R, Udaondo P, Salom D, García-García G, Millán JM. Expanding the Clinical and Molecular Heterogeneity of Nonsyndromic Inherited Retinal Dystrophies. J Mol Diagn 2020; 22:532-543. [PMID: 32036094 DOI: 10.1016/j.jmoldx.2020.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/01/2019] [Accepted: 01/12/2020] [Indexed: 12/21/2022] Open
Abstract
A cohort of 172 patients diagnosed clinically with nonsyndromic retinal dystrophies, from 110 families underwent full ophthalmologic examination, including retinal imaging, electrophysiology, and optical coherence tomography, when feasible. Molecular analysis was performed using targeted next-generation sequencing (NGS). Variants were filtered and prioritized according to the minimum allele frequency, and finally classified according to the American College of Medical Genetics and Genomics guidelines. Multiplex ligation-dependent probe amplification and array comparative genomic hybridization were performed to validate copy number variations identified by NGS. The diagnostic yield of this study was 62% of studied families. Thirty novel mutations were identified. The study found phenotypic intra- and interfamilial variability in families with mutations in C1QTNF5, CERKL, and PROM1; biallelic mutations in PDE6B in a unilateral retinitis pigmentosa patient; interocular asymmetry RP in 50% of the symptomatic RPGR-mutated females; the first case with possible digenism between CNGA1 and CNGB1; and a ROM1 duplication in two unrelated retinitis pigmentosa families. Ten unrelated cases were reclassified. This study highlights the clinical utility of targeted NGS for nonsyndromic inherited retinal dystrophy cases and the importance of full ophthalmologic examination, which allows new genotype-phenotype associations and expands the knowledge of this group of disorders. Identifying the cause of disease is essential to improve patient management, provide accurate genetic counseling, and take advantage of gene therapy-based treatments.
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Affiliation(s)
- Ana Rodríguez-Muñoz
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Unidad Mixta de Enfermedades raras IIS La Fe-Centro de Investigación Príncipe Felipe, Valencia, Spain; Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Unidad Mixta de Enfermedades raras IIS La Fe-Centro de Investigación Príncipe Felipe, Valencia, Spain; Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, Valencia, Spain; Genetics Unit, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Unidad Mixta de Enfermedades raras IIS La Fe-Centro de Investigación Príncipe Felipe, Valencia, Spain; Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, Valencia, Spain; Genetics Unit, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Emilio González-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Departments of Neurophysiology, Hospital de Manises, Valencia, Spain
| | | | - Roberto Gallego-Pinazo
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Macula Unit, Oftalvist Clinic, Valencia, Spain
| | - Patricia Udaondo
- Ophthalmology, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - David Salom
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, Valencia, Spain; Departments of Ophthalmology, Hospital de Manises, Valencia, Spain
| | - Gema García-García
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Unidad Mixta de Enfermedades raras IIS La Fe-Centro de Investigación Príncipe Felipe, Valencia, Spain; Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
| | - José M Millán
- Molecular, Cellular and Genomics Biomedicine Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Unidad Mixta de Enfermedades raras IIS La Fe-Centro de Investigación Príncipe Felipe, Valencia, Spain; Biomedical Research Network for Rare Diseases, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
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19
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Chakraborty D, Strayve DG, Makia MS, Conley SM, Kakahel M, Al-Ubaidi MR, Naash MI. Novel molecular mechanisms for Prph2-associated pattern dystrophy. FASEB J 2019; 34:1211-1230. [PMID: 31914632 DOI: 10.1096/fj.201901888r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/10/2019] [Accepted: 11/14/2019] [Indexed: 01/16/2023]
Abstract
Mutations in peripherin 2 (PRPH2) have been associated with retinitis pigmentosa (RP) and macular/pattern dystrophies, but the origin of this phenotypic variability is unclear. The majority of Prph2 mutations are located in the large intradiscal loop (D2), a region that contains seven cysteines involved in intra- and intermolecular disulfide bonding and protein folding. A mutation at cysteine 213, which is engaged in an intramolecular disulfide bond, leads to butterfly-shaped pattern dystrophy in humans, in sharp contrast to mutations in the adjacent cysteine at position 214 which result in RP. To help understand this unexpected phenotypic variability, we generated a knockin mouse line carrying the C213Y disease mutation. The mutant Prph2 protein lost the ability to oligomerize with rod outer segment membrane protein 1 (Rom1), but retained the ability to form homotetramers. C213Y heterozygotes had significantly decreased overall Prph2 levels as well as decreased rod and cone function. Critically, supplementation with extra wild-type Prph2 protein elicited improvements in Prph2 protein levels and rod outer segment structure, but not functional rescue in rods or cones. These findings suggest that not all interruptions of D2 loop intramolecular disulfide bonding lead to haploinsufficiency-related RP, but rather that more subtle changes can lead to mutant proteins stable enough to exert gain-of-function defects in rods and cones. This outcome highlights the difficulty in targeting Prph2-associated gain-of-function disease and suggests that elimination of the mutant protein will be a pre-requisite for any curative therapeutic strategy.
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Affiliation(s)
- Dibyendu Chakraborty
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA.,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Daniel G Strayve
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Mustafa S Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Mashal Kakahel
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
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20
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Grzybowski A, Kanclerz P. The Role of Steroids and NSAIDs in Prevention and Treatment of Postsurgical Cystoid Macular Edema. Curr Pharm Des 2019; 24:4896-4902. [PMID: 30727876 DOI: 10.2174/1381612825666190206104524] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/24/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Pseudophakic cystoid macular edema (PCME) remains one of the most common visionthreatening complication of phacoemulsification cataract surgery (PCS). Pharmacological therapy is the current mainstay of both prophylaxis, and treatment of PCME in patients undergoing PCS. We aimed to review pharmacological treatment options for PCME, which primarily include topical steroids, topical nonsteroidal antiinflammatory drugs (NSAIDS), periocular and intravitreal steroids, as well as anti-vascular endothelial growth factor therapy. METHODS The PubMed and Web Of Science web platforms were used to find relevant studies using the following keywords: cataract surgery, phacoemulsification, cystoid macular edema, and pseudophakic cystoid macular edema. Of articles retrieved by this method, all publications in English and abstracts of non-English publications were reviewed. Other studies were also considered as a potential source of information when referenced in relevant articles. The search revealed 193 publications. Finally 82 articles dated from 1974 to 2018 were assessed as significant and analyzed. RESULTS Based on the current literature, we found that corticosteroids remain the mainstay of PCME prophylaxis in uncomplicated cataract surgery, while it is still unclear if NSAID can offer additional benefits. In patients at risk for PCME development, periocular subconjunctival injection of triamcinolone acetonide may prevent PCME development. For PCME treatment the authors recommend a stepwise therapy: initial topical steroids and adjuvant NSAIDs, followed by additional posterior sub-Tenon or retrobulbar corticosteroids in moderate PCME, and intravitreal corticosteroids in recalcitrant PCME. Intravitreal anti-vascular endothelial growth factor agents may be considered in patients unresponsive to steroid therapy at risk of elevated intraocular pressure, and with comorbid macular disease. CONCLUSION Therapy with topical corticosteroids and NSAIDs is the mainstay of PCME prophylaxis and treatment, however, periocular and intravitreal steroids should be considered in refractory cases.
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Affiliation(s)
- Andrzej Grzybowski
- Department of Ophthalmology, University of Warmia and Mazury, Olsztyn, Poland.,Institute for Research in Ophthalmology, Foundation for Ophthalmology Development, Poznan, Poland
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21
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Battaglia Parodi M, Romano F, Marchese A, Arrigo A, Llorenç V, Cicinelli MV, Bandello F, Adán A. Anti-VEGF treatment for choroidal neovascularization complicating pattern dystrophy-like deposit associated with pseudoxanthoma elasticum. Graefes Arch Clin Exp Ophthalmol 2018; 257:273-278. [DOI: 10.1007/s00417-018-4190-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/11/2018] [Accepted: 11/15/2018] [Indexed: 11/28/2022] Open
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22
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Ebran JM, Martin L, Navasiolava N, Ferre M, Milea D, Leruez S. Subretinal fibrosis is associated with fundus pulverulentus in pseudoxanthoma elasticum. Graefes Arch Clin Exp Ophthalmol 2018; 256:699-707. [PMID: 29480367 DOI: 10.1007/s00417-018-3937-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 02/09/2018] [Accepted: 02/15/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Pseudoxanthoma elasticum (PXE) is a rare autosomal recessive disorder caused by mutations in the ABCC6 gene, resulting in various retinal lesions, among other systemic manifestations. Visual loss may occur in PXE, most commonly caused by choroidal neovascularization and macular atrophy, but little is known about the consequences of fundus pulverulentus (FP) in PXE. The aim of this study was to evaluate ophthalmic outcomes in patients with FP associated with PXE in a large series of PXE patients. METHODS In a retrospective observational study, ophthalmic outcomes were compared between two groups of age-matched patients with genetically and pathologically confirmed PXE: one group with FP versus one without FP. All included patients underwent thorough clinical examination. Further investigation (optical coherence tomography (OCT), Cirrhus, Zeiss Germany, and/or fluorescein/indocyanin green angiography) was performed in cases of suspected choroidal neovascularization (CNV). RESULTS The study included 13 PXE patients with FP (group 1: 8 men and 5 women, aged 45-65 years) and 47 age-matched PXE patients without FP (group 2: 19 men and 28 women). Mean patient follow-up was 63 months (range 0-132 months). Subretinal fibrosis (SRF) was more frequently associated with FP (9/26 eyes, 34.6%), compared to absence of FP (4/94, 4.2%) (p = 0.0001). Independently of SRF, FP can evolve into deep macular atrophy and/or CNV with dramatic consequences for central vision. CONCLUSIONS Fundus pulverulentus may occur in PXE and is most commonly associated with subretinal fibrosis in the posterior pole and visual loss by macular atrophy even in the absence of CNV.
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Affiliation(s)
- J M Ebran
- Ophthalmology Department, CHU Angers, Angers, France.
- PXE Referral Center, Angers University Hospital, Angers, France.
| | - L Martin
- PXE Referral Center, Angers University Hospital, Angers, France
- Dermatology Department, CHU Angers, Angers, France
- Mitovasc, Institute CNRS 6015, INSERM U 1083, University of Angers, Angers, France
| | - N Navasiolava
- PXE Referral Center, Angers University Hospital, Angers, France
| | - M Ferre
- Mitovasc, Institute CNRS 6015, INSERM U 1083, University of Angers, Angers, France
| | - D Milea
- Ophthalmology Department, CHU Angers, Angers, France
- Singapore National Eye Center, Singapore Eye Research Hospital and Duke-NUS, Singapore, Singapore
| | - S Leruez
- Ophthalmology Department, CHU Angers, Angers, France
- PXE Referral Center, Angers University Hospital, Angers, France
- Mitovasc, Institute CNRS 6015, INSERM U 1083, University of Angers, Angers, France
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Conley SM, Stuck MW, Watson JN, Naash MI. Rom1 converts Y141C-Prph2-associated pattern dystrophy to retinitis pigmentosa. Hum Mol Genet 2017; 26:509-518. [PMID: 28053051 PMCID: PMC6075606 DOI: 10.1093/hmg/ddw408] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/02/2016] [Accepted: 11/21/2016] [Indexed: 12/15/2022] Open
Abstract
Mutations in peripherin 2 (PRPH2), also known as retinal degeneration slow/RDS, lead to various retinal degenerations including retinitis pigmentosa (RP) and macular/pattern dystrophy (MD/PD). PRPH2-associated disease is often characterized by a phenotypic variability even within families carrying the same mutation, raising interest in potential modifiers. PRPH2 oligomerizes with its homologue rod outer segment (OS) membrane protein 1 (ROM1), and non-pathogenic PRPH2/ROM1 mutations, when present together, lead to digenic RP. We asked whether ROM1 could modify the phenotype of a PRPH2 mutation associated with a high degree of intrafamilial phenotypic heterogeneity: Y141C. In vitro, Y141C-Prph2 showed signs of retention in the endoplasmic reticulum (ER), however co-expression with Rom1 rescued this phenotype. In the heterozygous Y141C knockin mouse model (Prph2Y/+), Y141C-Prph2 and Rom1 formed abnormal complexes but were present at normal levels. Abnormal complexes were eliminated in the absence of Rom1 (Prph2Y/+/Rom1-/-) and total Prph2 levels were reduced to those found in the haploinsufficient Prph2+/- RP model. The biochemical changes had functional and structural consequences; while Prph2Y/+ animals exhibited a cone-rod electroretinogram defect, Prph2Y/+/Rom1-/- animals displayed a rod-dominant phenotype and OSs similar to those seen in the Prph2+/-. These data show that ablation of Rom1 results in the conversion of an MD/PD phenotype characterized by cone functional defects and the formation of abnormal Prph2/Rom1 complexes to an RP phenotype characterized by rod-dominant functional defects and reductions in total Prph2 protein. Thus one method by which ROM1 may act as a disease modifier is by contributing to the large variability in PRPH2-associated disease phenotypes.
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Affiliation(s)
- Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Michael W. Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Jamie N. Watson
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
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Diagnostic and Therapeutic Challenges. Retina 2017; 37:405-408. [DOI: 10.1097/iae.0000000000001176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Mutations in CTNNA1 cause butterfly-shaped pigment dystrophy and perturbed retinal pigment epithelium integrity. Nat Genet 2015; 48:144-51. [PMID: 26691986 PMCID: PMC4787620 DOI: 10.1038/ng.3474] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 11/25/2015] [Indexed: 11/11/2022]
Abstract
Butterfly-shaped pigment dystrophy is an eye disease characterized by lesions in the macula that can resemble the wings of a butterfly. Here, we report the identification of heterozygous missense mutations in the α-catenin 1 (CTNNA1) gene in three families with butterfly-shaped pigment dystrophy. In addition, we identified a Ctnna1 missense mutation in a chemically induced mouse mutant, tvrm5. Parallel clinical phenotypes were observed in the retinal pigment epithelium (RPE) of individuals with butterfly-shaped pigment dystrophy and in tvrm5 mice, including pigmentary abnormalities, focal thickening and elevated lesions, and decreased light-activated responses. Morphological studies in tvrm5 mice revealed increased cell shedding and large multinucleated RPE cells, suggesting defects in intercellular adhesion and cytokinesis. This study identifies CTNNA1 gene variants as a cause of macular dystrophy, suggests that CTNNA1 is involved in maintaining RPE integrity, and suggests that other components that participate in intercellular adhesion may be implicated in macular disease.
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Zulliger R, Conley SM, Mwoyosvi ML, Stuck MW, Azadi S, Naash MI. SNAREs Interact with Retinal Degeneration Slow and Rod Outer Segment Membrane Protein-1 during Conventional and Unconventional Outer Segment Targeting. PLoS One 2015; 10:e0138508. [PMID: 26406599 PMCID: PMC4583372 DOI: 10.1371/journal.pone.0138508] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/31/2015] [Indexed: 12/31/2022] Open
Abstract
Mutations in the photoreceptor protein peripherin-2 (also known as RDS) cause severe retinal degeneration. RDS and its homolog ROM-1 (rod outer segment protein 1) are synthesized in the inner segment and then trafficked into the outer segment where they function in tetramers and covalently linked larger complexes. Our goal is to identify binding partners of RDS and ROM-1 that may be involved in their biosynthetic pathway or in their function in the photoreceptor outer segment (OS). Here we utilize several methods including mass spectrometry after affinity purification, in vitro co-expression followed by pull-down, in vivo pull-down from mouse retinas, and proximity ligation assay to identify and confirm the SNARE proteins Syntaxin 3B and SNAP-25 as novel binding partners of RDS and ROM-1. We show that both covalently linked and non-covalently linked RDS complexes interact with Syntaxin 3B. RDS in the mouse is trafficked from the inner segment to the outer segment by both conventional (i.e., Golgi dependent) and unconventional secretory pathways, and RDS from both pathways interacts with Syntaxin3B. Syntaxin 3B and SNAP-25 are enriched in the inner segment (compared to the outer segment) suggesting that the interaction with RDS/ROM-1 occurs in the inner segment. Syntaxin 3B and SNAP-25 are involved in mediating fusion of vesicles carrying other outer segment proteins during outer segment targeting, so could be involved in the trafficking of RDS/ROM-1.
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Affiliation(s)
- Rahel Zulliger
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America
| | - Maggie L. Mwoyosvi
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America
| | - Michael W. Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America
| | - Seifollah Azadi
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America
| | - Muna I. Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, 73104, United States of America
- * E-mail:
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Conley SM, Naash MI. Gene therapy for PRPH2-associated ocular disease: challenges and prospects. Cold Spring Harb Perspect Med 2014; 4:a017376. [PMID: 25167981 DOI: 10.1101/cshperspect.a017376] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The peripherin-2 (PRPH2) gene encodes a photoreceptor-specific tetraspanin protein called peripherin-2/retinal degeneration slow (RDS), which is critical for the formation and maintenance of rod and cone outer segments. Over 90 different disease-causing mutations in PRPH2 have been identified, which cause a variety of forms of retinitis pigmentosa and macular degeneration. Given the disease burden associated with PRPH2 mutations, the gene has long been a focus for preclinical gene therapy studies. Adeno-associated viruses and compacted DNA nanoparticles carrying PRPH2 have been successfully used to mediate improvement in the rds(-/-) and rds(+/-) mouse models. However, complexities in the pathogenic mechanism for PRPH2-associated macular disease coupled with the need for a precise dose of peripherin-2 to combat a severe haploinsufficiency phenotype have delayed the development of clinically viable genetic treatments. Here we discuss the progress and prospects for PRPH2-associated gene therapy.
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Affiliation(s)
- Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Muna I Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
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Stuck MW, Conley SM, Naash MI. The Y141C knockin mutation in RDS leads to complex phenotypes in the mouse. Hum Mol Genet 2014; 23:6260-74. [PMID: 25001182 DOI: 10.1093/hmg/ddu345] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mutations in the photoreceptor-specific gene peripherin-2 (PRPH-2, also known as retinal degeneration slow/RDS) cause incurable retinal degeneration with a high degree of phenotypic variability. Patient phenotypes range from retinitis pigmentosa to various forms of macular and pattern dystrophy. Macular and pattern dystrophy in particular are associated with complex, poorly understood disease mechanisms, as severe vision loss is often associated both with defects in the photoreceptors, as well as the choroid and retinal pigment epithelium (RPE). Since there is currently no satisfactory model to study pattern dystrophy disease mechanisms, we generated a knockin mouse model expressing an RDS pattern dystrophy mutation, Y141C. Y141C mice exhibited clinical signs similar to those in patients including late-onset fundus abnormalities characteristic of RPE and choroidal defects and electroretinogram defects. Ultrastructural examination indicated that disc formation was initiated by the Y141C protein, but proper sizing and alignment of discs required wild-type RDS. The biochemical mechanism underlying these abnormalities was tied to defects in the normal process of RDS oligomerization which is required for proper RDS function. Y141C-RDS formed strikingly abnormal disulfide-linked complexes which were localized to the outer segment (OS) where they impaired the formation of proper OS structure. These data support a model of pattern dystrophy wherein a primary molecular defect occurring in all photoreceptors leads to secondary sequellae in adjacent tissues, an outcome which leads to macular vision loss. An understanding of the role of RDS in the interplay between these tissues significantly enhances our understanding of RDS-associated pathobiology and our ability to design rational treatment strategies.
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Affiliation(s)
- Michael W Stuck
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Muna I Naash
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Saksens NT, Fleckenstein M, Schmitz-Valckenberg S, Holz FG, den Hollander AI, Keunen JE, Boon CJ, Hoyng CB. Macular dystrophies mimicking age-related macular degeneration. Prog Retin Eye Res 2014; 39:23-57. [PMID: 24291520 DOI: 10.1016/j.preteyeres.2013.11.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 01/30/2023]
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