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McNamee SM, Akula M, Love Z, Nasraty N, Nystuen K, Singh P, Upadhyay AK, DeAngelis MM, Haider NB. Evaluating therapeutic potential of NR2E3 doses in the rd7 mouse model of retinal degeneration. Sci Rep 2024; 14:16490. [PMID: 39019967 PMCID: PMC11254931 DOI: 10.1038/s41598-024-67095-6] [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: 03/25/2024] [Accepted: 07/08/2024] [Indexed: 07/19/2024] Open
Abstract
Retinitis Pigmentosa is a leading cause of severe vision loss. Retinitis Pigmentosa can present with a broad range of phenotypes impacted by disease age of onset, severity, and progression. This variation is influenced both by different gene mutations as well as unique variants within the same gene. Mutations in the nuclear hormone receptor 2 family e, member 3 are associated with several forms of retinal degeneration, including Retinitis Pigmentosa. In our previous studies we demonstrated that subretinal administration of one Nr2e3 dose attenuated retinal degeneration in rd7 mice for at least 3 months. Here we expand the studies to evaluate the efficacy and longitudinal impact of the NR2E3 therapeutic by examining three different doses administered at early or intermediate stages of retinal degeneration in the rd7 mice. Our study revealed retinal morphology was significantly improved 6 months post for all doses in the early-stage treatment groups and for the low and mid doses in the intermediate stage treatment groups. Similarly, photoreceptor function was significantly improved in the early stage for all doses and intermediate stage low and mid dose groups 6 months post treatment. This study demonstrated efficacy in multiple doses of NR2E3 therapy.
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Affiliation(s)
- Shannon M McNamee
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Monica Akula
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Zoe Love
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Neelaab Nasraty
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Kaden Nystuen
- University of Massachusetts Amherst, Amherst, MA, USA
| | | | | | - Margaret M DeAngelis
- Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Neena B Haider
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA.
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02138, USA.
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2
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Hassanpoor N, Ebrahimiadib N, Riazi-Esfahani H, Moghaddasi A, Suri F. Bilateral helicoid peri-papillary sub-retinal fibrosis due to a biallelic NR2E3 mutation: Describing variable expressivity of a mutation. Eur J Ophthalmol 2024:11206721241234396. [PMID: 38444285 DOI: 10.1177/11206721241234396] [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: 03/07/2024]
Abstract
BACKGROUND To describe different clinical presentations of a same NR2E3 recessive mutation in two families and within one family. DESIGN Interventional family study. RESULTS Our first case was a one-year-old male child with high hyperopia and refractive accommodative esotropia. In retinal examination, peri-papillary sub-retinal fibrosis with a helicoid configuration was observed in both eyes. The parents and the only sibling had no pathologic findings in the eyes. The child showed to have severely reduced responses in both photopic and scotopic electroretinogram components. In the genetic investigation, a homozygous autosomal recessive mutation in the NR2E3 gene (IVS1-2A > C) was discovered in the affected child, while the other family members were heterozygous for this mutation. We followed up with the patient for 3 years and no new lesion developed during this period. The second case was a 13-year-old male child referred to the retina clinic for decreased vision in the right eye. In retina examination, there were nummular pigmentary changes at the level of retinal pigment epithelium and along the vascular arcades with foveo-schitic changes in both eyes. A choroidal neovascularization (CNV) was noticed in the macula of his right eye. The genetic evaluation proved the same mutation in the NR2E3 gene as in the first case. Family history was remarkable for an uncle, an aunt, and two cousins with night blindness. CONCLUSION Same NR2E3 gene mutation can cause heterogeneous clinical manifestations such as slight retinal changes in the absence of any visual symptoms to high hyperopia associated with helicoid peri-papillary sub-retinal fibrosis.
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Affiliation(s)
- Narges Hassanpoor
- Retina & Vitreous Service, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Nazanin Ebrahimiadib
- Department of Ophthalmology, University of Florida, College of Medicine, Gainesville, FL, USA
| | - Hamid Riazi-Esfahani
- Retina & Vitreous Service, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Afrooz Moghaddasi
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Suri
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Haraguchi Y, Chiang TK, Yu M. Application of Electrophysiology in Non-Macular Inherited Retinal Dystrophies. J Clin Med 2023; 12:6953. [PMID: 37959417 PMCID: PMC10649281 DOI: 10.3390/jcm12216953] [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: 07/23/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
Inherited retinal dystrophies encompass a diverse group of disorders affecting the structure and function of the retina, leading to progressive visual impairment and, in severe cases, blindness. Electrophysiology testing has emerged as a valuable tool in assessing and diagnosing those conditions, offering insights into the function of different parts of the visual pathway from retina to visual cortex and aiding in disease classification. This review provides an overview of the application of electrophysiology testing in the non-macular inherited retinal dystrophies focusing on both common and rare variants, including retinitis pigmentosa, progressive cone and cone-rod dystrophy, bradyopsia, Bietti crystalline dystrophy, late-onset retinal degeneration, and fundus albipunctatus. The different applications and limitations of electrophysiology techniques, including multifocal electroretinogram (mfERG), full-field ERG (ffERG), electrooculogram (EOG), pattern electroretinogram (PERG), and visual evoked potential (VEP), in the diagnosis and management of these distinctive phenotypes are discussed. The potential for electrophysiology testing to allow for further understanding of these diseases and the possibility of using these tests for early detection, prognosis prediction, and therapeutic monitoring in the future is reviewed.
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Affiliation(s)
| | | | - Minzhong Yu
- Department of Ophthalmology, University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA
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Xiao S, Yi Z, Xiao X, Li S, Jia X, Lian P, Sun W, Wang P, Lu L, Zhang Q. Clinical and Genetic Features of NR2E3-Associated Retinopathy: A Report of Eight Families with a Longitudinal Study and Literature Review. Genes (Basel) 2023; 14:1525. [PMID: 37628579 PMCID: PMC10454055 DOI: 10.3390/genes14081525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/27/2023] Open
Abstract
(1) Background: NR2E3 encodes a nuclear receptor transcription factor that is considered to promote cell differentiation, affect retinal development, and regulate phototransduction in rods and cones. This study aimed to analyze the clinical characteristics and observe the prognosis of autosomal dominant retinopathy (ADRP) and autosomal recessive retinopathy (ARRP) associated with NR2E3; (2) Methods: NR2E3 variants were collected from our exome sequencing data and identified per the American College of Medical Genetics and Genomics criteria. Data from our cohort and a systemic literature review were conducted to explore the NR2E3 variants spectrum and potential genotype-phenotype correlations; (3) Results: Nine pathogenic variants/likely pathogenic variants in NR2E3, including five novel variants, were detected in eight families (four each with ADRP and ARRP). Follow-up data showed schisis/atrophy in the macula and retinal degeneration initiation around the vascular arcades with differences in ADRP and ARRP. A systemic literature review indicated patients with ADRP presented better visual acuity (p < 0.01) and later onset age (p < 0.0001) than did those with ARRP; (4) Conclusions: Macular schisis and retinal degeneration around vascular arcades may present as the prognosis of NR2E3-retinopathy, dominant, or recessive. Our data might further enrich our understanding of NR2E3 variants and associated inherited retinopathy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China; (S.X.); (Z.Y.); (X.X.); (S.L.); (X.J.); (P.L.); (W.S.); (P.W.); (L.L.)
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Toms M, Ward N, Moosajee M. Nuclear Receptor Subfamily 2 Group E Member 3 (NR2E3): Role in Retinal Development and Disease. Genes (Basel) 2023; 14:1325. [PMID: 37510230 PMCID: PMC10379133 DOI: 10.3390/genes14071325] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/11/2023] [Accepted: 06/19/2023] [Indexed: 07/30/2023] Open
Abstract
NR2E3 is a nuclear hormone receptor gene required for the correct development of the retinal rod photoreceptors. Expression of NR2E3 protein in rod cell precursors suppresses cone-specific gene expression and, in concert with other transcription factors including NRL, activates the expression of rod-specific genes. Pathogenic variants involving NR2E3 cause a spectrum of retinopathies, including enhanced S-cone syndrome, Goldmann-Favre syndrome, retinitis pigmentosa, and clumped pigmentary retinal degeneration, with limited evidence of genotype-phenotype correlations. A common feature of NR2E3-related disease is an abnormally high number of cone photoreceptors that are sensitive to short wavelength light, the S-cones. This characteristic has been supported by mouse studies, which have also revealed that loss of Nr2e3 function causes photoreceptors to develop as cells that are intermediate between rods and cones. While there is currently no available cure for NR2E3-related retinopathies, there are a number of emerging therapeutic strategies under investigation, including the use of viral gene therapy and gene editing, that have shown promise for the future treatment of patients with NR2E3 variants and other inherited retinal diseases. This review provides a detailed overview of the current understanding of the role of NR2E3 in normal development and disease, and the associated clinical phenotypes, animal models, and therapeutic studies.
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Affiliation(s)
- Maria Toms
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Ocular Genomics and Therapeutics, The Francis Crick Institute, London NW1 1AT, UK
| | - Natasha Ward
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London EC1V 9EL, UK
| | - Mariya Moosajee
- Development, Ageing and Disease, UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Ocular Genomics and Therapeutics, The Francis Crick Institute, London NW1 1AT, UK
- Department of Genetics, Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Department of Ophthalmology, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
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6
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Buckley TM, Cehajic-Kapetanovic J, Shanks M, Clouston P, MacLaren RE. Compound dominant-null heterozygosity in a family with RP1-related retinal dystrophy. Am J Ophthalmol Case Rep 2022; 28:101698. [PMID: 36393903 PMCID: PMC9650022 DOI: 10.1016/j.ajoc.2022.101698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/15/2022] [Accepted: 09/01/2022] [Indexed: 11/20/2022] Open
Abstract
Purpose To report on the presence of autosomal dominant and compound dominant-null RP1-related retinitis pigmentosa in the same non-consanguineous family. Observation The father was minimally symptomatic and referred by his optometrist aged 38. He was diagnosed with rod-cone dystrophy, confirmed to be caused by the previously reported RP1 c.2613dupA mutation. He was reassured that his 11-year-old daughter had a 50% chance of inheriting the same mutation and that the condition, if she had it, would most likely be similar. Clinical phenotyping of his daughter however revealed an early onset cone-rod dystrophy. The mother was entirely asymptomatic and clinically normal. Sanger sequencing of the RP1 gene in the daughter confirmed the presence of biallelic mutations - the dominant c.2613dupA variant from her father and a c.3843dupT truncating variant inherited from her mother, both located in exon 4 of the RP1 gene. The maternal c.3843dupT has previously been reported. Conclusions and importance Pathogenic variants in exon 4 of RP1 are known to cause differential dominant and recessive disease. The presence of both phenotypes in a single family has not yet been reported. The father, being minimally symptomatic, is affected by a known dominant variant which truncates the RP1 protein more proximally. However, inheritance of both variants in a compound heterozygous state in the daughter resulted in a much more severe, early onset cone-rod phenotype in a pattern akin to recessive disease. This raises challenges for genetic counselling and development of gene-based therapies for RP1 mutations.
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Affiliation(s)
- Thomas M.W. Buckley
- Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way, OX3 9DU, UK
| | | | - Morag Shanks
- Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way, OX3 9DU, UK
| | - Penny Clouston
- Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way, OX3 9DU, UK
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Level 6, West Wing, John Radcliffe Hospital, Headley Way, OX3 9DU, UK
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Nieves FR, Villegas VM, Patel NA, Berrocal AM, Murray TG. Multimodal treatment of Coats-like exudative vitreoretinopathy in Goldmann-Favre syndrome. Am J Ophthalmol Case Rep 2022; 25:101362. [PMID: 35243140 PMCID: PMC8859797 DOI: 10.1016/j.ajoc.2022.101362] [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: 04/21/2021] [Revised: 07/30/2021] [Accepted: 01/22/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose To report a Coats-like exudative vitreoretinopathy in Goldmann-Favre syndrome. Observations A 64 year-old woman with prior diagnosis of retinal dystrophy presented with decreased vision in the right eye (OD). Ophthalmologic examination was remarkable for bilateral arteriolar attenuation, mid-peripheral bony-spicules, and waxy disc pallor. Coats-like exudative vitreoretinopathy and cystoid macular edema were present OD. Genetic testing showed a homozygous pathogenic mutation in gene NR2E3, variant c.932G>A (p.Arg311Gln), consistent with Goldmann-Favre syndrome. Targeted laser ablation and combination intravitreal therapy were effective in decreasing macular edema. Conclusions and Importance A Coats-like exudative vitreoretinopathy may occur in the setting of Goldmann-Favre syndrome. Targeted laser ablation in combination with intravitreal therapy can be efficacious in select patients.
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8
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Venturini G, Kokona D, Steiner BL, Bulla EG, Jovanovic J, Zinkernagel MS, Escher P. In vivo analysis of onset and progression of retinal degeneration in the Nr2e3 rd7/rd7 mouse model of enhanced S-cone sensitivity syndrome. Sci Rep 2021; 11:19032. [PMID: 34561487 PMCID: PMC8463594 DOI: 10.1038/s41598-021-98271-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 09/06/2021] [Indexed: 12/02/2022] Open
Abstract
The photoreceptor-specific nuclear receptor Nr2e3 is not expressed in Nr2e3rd7/rd7 mice, a mouse model of the recessively inherited retinal degeneration enhanced S-cone sensitivity syndrome (ESCS). We characterized in detail C57BL/6J Nr2e3rd7/rd7 mice in vivo by fundus photography, optical coherence tomography and fluorescein angiography and, post mortem, by histology and immunohistochemistry. White retinal spots and so-called 'rosettes' first appear at postnatal day (P) 12 in the dorsal retina and reach maximal expansion at P21. The highest density in 'rosettes' is observed within a region located between 100 and 350 µM from the optic nerve head. 'Rosettes' disappear between 9 to 12 months. Non-apoptotic cell death markers are detected during the slow photoreceptor degeneration, at a rate of an approximately 3% reduction of outer nuclear layer thickness per month, as observed from 7 to 31 months of age. In vivo analysis of Nr2e3rd7/rd7 Cx3cr1gfp/+ retinas identified microglial cells within 'rosettes' from P21 on. Subretinal macrophages were observed in vivo and by confocal microscopy earliest in 12-months-old Nr2e3rd7/rd7 retinas. At P21, S-opsin expression and the number of S-opsin expressing dorsal cones was increased. The dorso-ventral M-cone gradient was present in Nr2e3rd7/rd7 retinas, but M-opsin expression and M-opsin expressing cones were decreased. Retinal vasculature was normal.
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Affiliation(s)
- Giulia Venturini
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Beatrice L Steiner
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Emanuele G Bulla
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Joel Jovanovic
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Pascal Escher
- Department of Ophthalmology, Inselspital, Bern University Hospital, Bern, Switzerland.
- Department of BioMedical Research, University of Bern, Bern, Switzerland.
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Diakatou M, Dubois G, Erkilic N, Sanjurjo-Soriano C, Meunier I, Kalatzis V. Allele-Specific Knockout by CRISPR/Cas to Treat Autosomal Dominant Retinitis Pigmentosa Caused by the G56R Mutation in NR2E3. Int J Mol Sci 2021; 22:ijms22052607. [PMID: 33807610 PMCID: PMC7961898 DOI: 10.3390/ijms22052607] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/01/2021] [Accepted: 03/03/2021] [Indexed: 12/18/2022] Open
Abstract
Retinitis pigmentosa (RP) is an inherited retinal dystrophy that causes progressive vision loss. The G56R mutation in NR2E3 is the second most common mutation causing autosomal dominant (ad) RP, a transcription factor that is essential for photoreceptor development and maintenance. The G56R variant is exclusively responsible for all cases of NR2E3-associated adRP. Currently, there is no treatment for NR2E3-related or, other, adRP, but genome editing holds promise. A pertinent approach would be to specifically knockout the dominant mutant allele, so that the wild type allele can perform unhindered. In this study, we developed a CRISPR/Cas strategy to specifically knockout the mutant G56R allele of NR2E3 and performed a proof-of-concept study in induced pluripotent stem cells (iPSCs) of an adRP patient. We demonstrate allele-specific knockout of the mutant G56R allele in the absence of off-target events. Furthermore, we validated this knockout strategy in an exogenous overexpression system. Accordingly, the mutant G56R-CRISPR protein was truncated and mis-localized to the cytosol in contrast to the (peri)nuclear localizations of wild type or G56R NR2E3 proteins. Finally, we show, for the first time, that G56R iPSCs, as well as G56R-CRISPR iPSCs, can differentiate into NR2E3-expressing retinal organoids. Overall, we demonstrate that G56R allele-specific knockout by CRISPR/Cas could be a clinically relevant approach to treat NR2E3-associated adRP.
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Affiliation(s)
- Michalitsa Diakatou
- INM, University of Montpellier, Inserm, 34091 Montpellier, France; (M.D.); (G.D.); (N.E.); (C.S.-S.); (I.M.)
| | - Gregor Dubois
- INM, University of Montpellier, Inserm, 34091 Montpellier, France; (M.D.); (G.D.); (N.E.); (C.S.-S.); (I.M.)
| | - Nejla Erkilic
- INM, University of Montpellier, Inserm, 34091 Montpellier, France; (M.D.); (G.D.); (N.E.); (C.S.-S.); (I.M.)
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, CHU, 34295 Montpellier, France
| | - Carla Sanjurjo-Soriano
- INM, University of Montpellier, Inserm, 34091 Montpellier, France; (M.D.); (G.D.); (N.E.); (C.S.-S.); (I.M.)
| | - Isabelle Meunier
- INM, University of Montpellier, Inserm, 34091 Montpellier, France; (M.D.); (G.D.); (N.E.); (C.S.-S.); (I.M.)
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, CHU, 34295 Montpellier, France
| | - Vasiliki Kalatzis
- INM, University of Montpellier, Inserm, 34091 Montpellier, France; (M.D.); (G.D.); (N.E.); (C.S.-S.); (I.M.)
- Correspondence:
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de Carvalho ER, Robson AG, Arno G, Boon CJF, Webster AA, Michaelides M. Enhanced S-Cone Syndrome: Spectrum of Clinical, Imaging, Electrophysiologic, and Genetic Findings in a Retrospective Case Series of 56 Patients. Ophthalmol Retina 2021; 5:195-214. [PMID: 32679203 PMCID: PMC7861019 DOI: 10.1016/j.oret.2020.07.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 11/19/2022]
Abstract
PURPOSE To describe the detailed phenotype, long-term clinical course, clinical variability, and genotype of patients with enhanced S-cone syndrome (ESCS). DESIGN Retrospective case series. PARTICIPANTS Fifty-six patients with ESCS. METHODS Clinical history, examination, imaging, and electrophysiologic findings of 56 patients (age range, 1-75 years) diagnosed with ESCS were reviewed. Diagnosis was established by molecular confirmation of disease-causing variants in the NR2E3 gene (n = 38) or by diagnostic full-field electroretinography findings (n = 18). MAIN OUTCOME MEASURES Age at onset of visual symptoms, best-corrected visual acuity (BCVA), quantitative age-related electrophysiologic decline, and imaging findings. RESULTS Mean age at onset of visual symptoms was 4.0 years, and median age at presentation was 20.5 years, with mean follow-up interval being 6.1 years. Six patients were assessed once. Disease-causing variants in NR2E3 were identified in 38 patients. Mean BCVA of the better-seeing eye was 0.32 logarithm of the minimum angle of resolution (logMAR) at baseline and 0.39 logMAR at follow-up. In most eyes (76% [76/100]), BCVA remained stable, with a mean BCVA change of 0.07 logMAR during follow-up. Nyctalopia was the most common initial symptom, reported in 92.9% of patients (52/56). Clinical findings were highly variable and included foveomacular schisis (41.1% [26/56]), yellow-white dots (57.1% [32/56]), nummular pigmentation (85.7% [48/56]), torpedo-like lesions (10.7% [6/56]), and circumferential subretinal fibrosis (7.1% [4/56]). Macular and peripheral patterns of autofluorescence were classified as (1) minimal change, (2) hypoautofluorescent (mild diffuse, moderate speckled, moderate diffuse, or advanced), or (3) hyperautofluorescent flecks. One patient showed undetectable electroretinography findings; quantification of main electroretinography components in all other patients revealed amplitude and peak time variability but with pathognomonic electroretinography features. The main electroretinography components showed evidence of age-related worsening over 6.7 decades, at a rate indistinguishable from that seen in unaffected control participants. Eighteen sequence variants in NR2E3 were identified, including 4 novel missense changes. CONCLUSIONS Enhanced S-cone syndrome has a highly variable phenotype with relative clinical and imaging stability over time. Most electroretinography findings have pathognomonic features, but quantitative assessment reveals variability and a normal mean rate of age-related decline, consistent with largely nonprogressive peripheral retinal dysfunction.
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Affiliation(s)
- Emanuel R de Carvalho
- Moorfields Eye Hospital, London, United Kingdom; Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Gavin Arno
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, The Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew A Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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11
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Iannaccone A, Brabbit E, Lopez-Miro C, Love Z, Griffiths V, Kedrov M, Haider NB. Interspecies Correlations between Human and Mouse NR2E3-Associated Recessive Disease. J Clin Med 2021; 10:jcm10030475. [PMID: 33513943 PMCID: PMC7865474 DOI: 10.3390/jcm10030475] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/13/2021] [Accepted: 01/18/2021] [Indexed: 11/16/2022] Open
Abstract
NR2E3-associated recessive disease in humans is historically defined by congenital night blinding retinopathy, characterized by an initial increase in short-wavelength (S)-cone sensitivity and progressive loss of rod and cone function. The retinal degeneration 7 (rd7) murine model, harboring a recessive mutation in the mouse ortholog of NR2E3, has been a well-studied disease model and recently evaluated as a therapeutic model for NR2E3-associated retinal degenerations. This study aims to draw parallels between human and mouse NR2E3-related disease through examination of spectral domain optical coherence tomography (SD-OCT) imaging between different stage of human disease and its murine counterpart. We propose that SD-OCT is a useful non-invasive diagnostic tool to compare human clinical dystrophy presentation with that of the rd7 mouse and make inference that may be of therapeutically relevance. Additionally, a longitudinal assessment of rd7 disease progression, utilizing available clinical data from our patients as well as extensive retrospective analysis of visual acuity data from published cases of human NR2E3-related disease, was curated to identify further valuable correlates between human and mouse Nr2e3 disease. Results of this study validate the slow progression of NR2E3-associated disease in humans and the rd7 mice and identify SD-OCT characteristics in patients at or near the vascular arcades that correlate well with the whorls and rosettes that are seen also in the rd7 mouse and point to imaging features that appear to be associated with better preserved S-cone mediated retinal function. The correlation of histological findings between rd7 mice and human imaging provides a solid foundation for diagnostic use of pathophysiological and prognostic information to further define characteristics and a relevant timeline for therapeutic intervention in the field of NR2E3-associated retinopathies.
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Affiliation(s)
- Alessandro Iannaccone
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC 27710, USA; (C.L.-M.); (V.G.); (M.K.)
- Correspondence: (A.I.); (N.B.H.)
| | - Emily Brabbit
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; (E.B.); (Z.L.)
| | - Christiaan Lopez-Miro
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC 27710, USA; (C.L.-M.); (V.G.); (M.K.)
| | - Zoe Love
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; (E.B.); (Z.L.)
| | - Victoria Griffiths
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC 27710, USA; (C.L.-M.); (V.G.); (M.K.)
| | - Marina Kedrov
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke Eye Center, Duke University School of Medicine, Durham, NC 27710, USA; (C.L.-M.); (V.G.); (M.K.)
| | - Neena B. Haider
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA; (E.B.); (Z.L.)
- Correspondence: (A.I.); (N.B.H.)
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12
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Al-khuzaei S, Broadgate S, Halford S, Jolly JK, Shanks M, Clouston P, Downes SM. Novel Pathogenic Sequence Variants in NR2E3 and Clinical Findings in Three Patients. Genes (Basel) 2020; 11:genes11111288. [PMID: 33138239 PMCID: PMC7716234 DOI: 10.3390/genes11111288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/21/2020] [Accepted: 10/28/2020] [Indexed: 01/08/2023] Open
Abstract
A retrospective review of the clinical records of patients seen at the Oxford Eye Hospital identified as having NR2E3 mutations was performed. The data included symptoms, best-corrected visual acuity, multimodal retinal imaging, visual fields and electrophysiology testing. Three participants were identified with biallelic NR2E3 pathogenic sequence variants detected using a targeted NGS gene panel, two of which were novel. Participant I was a Nepalese male aged 68 years, and participants II and III were white Caucasian females aged 69 and 10 years old, respectively. All three had childhood onset nyctalopia, a progressive decrease in central vision, and visual field loss. Patients I and III had photopsia, patient II had photosensitivity and patient III also had photophobia. Visual acuities in patients I and II were preserved even into the seventh decade, with the worst visual acuity measured at 6/36. Visual field constriction was severe in participant I, less so in II, and fields were full to bright targets targets in participant III. Electrophysiology testing in all three demonstrated loss of rod function. The three patients share some of the typical distinctive features of NR2E3 retinopathies, as well as a novel clinical observation of foveal ellipsoid thickening.
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Affiliation(s)
- Saoud Al-khuzaei
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-k.); (J.K.J.)
| | - Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (S.H.)
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (S.H.)
| | - Jasleen K. Jolly
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-k.); (J.K.J.)
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (S.H.)
| | - Morag Shanks
- Oxford Medical Genetics Laboratory, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 7LE, UK; (M.S.); (P.C.)
| | - Penny Clouston
- Oxford Medical Genetics Laboratory, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 7LE, UK; (M.S.); (P.C.)
| | - Susan M. Downes
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-k.); (J.K.J.)
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (S.H.)
- Correspondence:
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13
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Nr2e3 functional domain ablation by CRISPR-Cas9D10A identifies a new isoform and generates retinitis pigmentosa and enhanced S-cone syndrome models. Neurobiol Dis 2020; 146:105122. [PMID: 33007388 DOI: 10.1016/j.nbd.2020.105122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 12/18/2022] Open
Abstract
Mutations in NR2E3 cause retinitis pigmentosa (RP) and enhanced S-cone syndrome (ESCS) in humans. This gene produces a large isoform encoded in 8 exons and a previously unreported shorter isoform of 7 exons, whose function is unknown. We generated two mouse models by targeting exon 8 of Nr2e3 using CRISPR/Cas9-D10A nickase. Allele Δ27 is an in-frame deletion of 27 bp that ablates the dimerization domain H10, whereas allele ΔE8 (full deletion of exon 8) produces only the short isoform, which lacks the C-terminal part of the ligand binding domain (LBD) that encodes both H10 and the AF2 domain involved in the Nr2e3 repressor activity. The Δ27 mutant shows developmental alterations and a non-progressive electrophysiological dysfunction that resembles the ESCS phenotype. The ΔE8 mutant exhibits progressive retinal degeneration, as occurs in human RP patients. Our mutants suggest a role for Nr2e3 as a cone-patterning regulator and provide valuable models for studying mechanisms of NR2E3-associated retinal dystrophies and evaluating potential therapies.
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14
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Genome Editing as a Treatment for the Most Prevalent Causative Genes of Autosomal Dominant Retinitis Pigmentosa. Int J Mol Sci 2019; 20:ijms20102542. [PMID: 31126147 PMCID: PMC6567127 DOI: 10.3390/ijms20102542] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/15/2019] [Accepted: 05/22/2019] [Indexed: 02/07/2023] Open
Abstract
: Inherited retinal dystrophies (IRDs) are a clinically and genetically heterogeneous group of diseases with more than 250 causative genes. The most common form is retinitis pigmentosa. IRDs lead to vision impairment for which there is no universal cure. Encouragingly, a first gene supplementation therapy has been approved for an autosomal recessive IRD. However, for autosomal dominant IRDs, gene supplementation therapy is not always pertinent because haploinsufficiency is not the only cause. Disease-causing mechanisms are often gain-of-function or dominant-negative, which usually require alternative therapeutic approaches. In such cases, genome-editing technology has raised hopes for treatment. Genome editing could be used to i) invalidate both alleles, followed by supplementation of the wild type gene, ii) specifically invalidate the mutant allele, with or without gene supplementation, or iii) to correct the mutant allele. We review here the most prevalent genes causing autosomal dominant retinitis pigmentosa and the most appropriate genome-editing strategy that could be used to target their different causative mutations.
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15
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Antisense Oligonucleotide-Based Downregulation of the G56R Pathogenic Variant Causing NR2E3-Associated Autosomal Dominant Retinitis Pigmentosa. Genes (Basel) 2019; 10:genes10050363. [PMID: 31083481 PMCID: PMC6562693 DOI: 10.3390/genes10050363] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/28/2019] [Accepted: 05/06/2019] [Indexed: 12/11/2022] Open
Abstract
The recurrent missense variant in Nuclear Receptor Subfamily 2 Group E Member 3 (NR2E3), c.166G>A, p.(Gly56Arg) or G56R, underlies 1%–2% of cases with autosomal dominant retinitis pigmentosa (adRP), a frequent, genetically heterogeneous inherited retinal disease (IRD). The mutant NR2E3 protein has a presumed dominant negative effect (DNE) by competition for dimer formation with Cone-Rod Homeobox (CRX) but with abolishment of DNA binding, acting as a repressor in trans. Both the frequency and DNE of G56R make it an interesting target for allele-specific knock-down of the mutant allele using antisense oligonucleotides (AONs), an emerging therapeutic strategy for IRD. Here, we designed gapmer AONs with or without a locked nucleic acid modification at the site of the mutation, which were analyzed for potential off-target effects. Next, we overexpressed wild type (WT) or mutant NR2E3 in RPE-1 cells, followed by AON treatment. Transcript and protein levels of WT and mutant NR2E3 were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot respectively. All AONs showed a general knock-down of mutant and WT NR2E3 on RNA and protein level, showing the accessibility of the region for AON-induced knockdown. Further modifications are needed however to increase allele-specificity. In conclusion, we propose the first proof-of-concept for AON-mediated silencing of a single nucleotide variation with a dominant negative effect as a therapeutic approach for NR2E3-associated adRP.
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16
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Correction of NR2E3 Associated Enhanced S-cone Syndrome Patient-specific iPSCs using CRISPR-Cas9. Genes (Basel) 2019; 10:genes10040278. [PMID: 30959774 PMCID: PMC6523438 DOI: 10.3390/genes10040278] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 12/24/2022] Open
Abstract
Enhanced S-cone syndrome (ESCS) is caused by recessive mutations in the photoreceptor cell transcription factor NR2E3. Loss of NR2E3 is characterized by repression of rod photoreceptor cell gene expression, over-expansion of the S-cone photoreceptor cell population, and varying degrees of M- and L-cone photoreceptor cell development. In this study, we developed a CRISPR-based homology-directed repair strategy and corrected two different disease-causing NR2E3 mutations in patient-derived induced pluripotent stem cells (iPSCs) generated from two affected individuals. In addition, one patient’s iPSCs were differentiated into retinal cells and NR2E3 transcription was evaluated in CRISPR corrected and uncorrected clones. The patient’s c.119-2A>C mutation caused the inclusion of a portion of intron 1, the creation of a frame shift, and generation of a premature stop codon. In summary, we used a single set of CRISPR reagents to correct different mutations in iPSCs generated from two individuals with ESCS. In doing so we demonstrate the advantage of using retinal cells derived from affected patients over artificial in vitro model systems when attempting to demonstrate pathophysiologic mechanisms of specific mutations.
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17
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Anasagasti A, Ezquerra-Inchausti M, Barandika O, Muñoz-Culla M, Caffarel MM, Otaegui D, López de Munain A, Ruiz-Ederra J. Expression Profiling Analysis Reveals Key MicroRNA-mRNA Interactions in Early Retinal Degeneration in Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2019; 59:2381-2392. [PMID: 29847644 PMCID: PMC5939684 DOI: 10.1167/iovs.18-24091] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The aim of this study was to identify differentially expressed microRNAs (miRNAs) that might play an important role in the etiology of retinal degeneration in a genetic mouse model of retinitis pigmentosa (rd10 mice) at initial stages of the disease. Methods miRNAs–mRNA interaction networks were generated for analysis of biological pathways involved in retinal degeneration. Results Of more than 1900 miRNAs analyzed, we selected 19 miRNAs on the basis of (1) a significant differential expression in rd10 retinas compared with control samples and (2) an inverse expression relationship with predicted mRNA targets involved in biological pathways relevant to retinal biology and/or degeneration. Seven of the selected miRNAs have been associated with retinal dystrophies, whereas, to our knowledge, nine have not been previously linked to any disease. Conclusions This study contributes to our understanding of the etiology and progression of retinal degeneration.
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Affiliation(s)
- Ander Anasagasti
- Neuroscience Area, Sensorial Neurodegeneration Group, Biodonostia Health Research Institute, San Sebastian, Spain
| | - Maitane Ezquerra-Inchausti
- Neuroscience Area, Sensorial Neurodegeneration Group, Biodonostia Health Research Institute, San Sebastian, Spain.,RETICS OFTARED, National Institute of Health Carlos III, Ministry of Economy and Competitiveness, Spain
| | - Olatz Barandika
- Neuroscience Area, Sensorial Neurodegeneration Group, Biodonostia Health Research Institute, San Sebastian, Spain
| | - Maider Muñoz-Culla
- Neuroscience Area, Multiple Sclerosis Group, Biodonostia Health Research Institute, San Sebastian, Spain.,Spanish Network on Multiple Sclerosis (Red Española de Esclerosis Múltiple)
| | - María M Caffarel
- Oncology Area, Biodonostia Health Research Institute, San Sebastian, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - David Otaegui
- Neuroscience Area, Multiple Sclerosis Group, Biodonostia Health Research Institute, San Sebastian, Spain.,Spanish Network on Multiple Sclerosis (Red Española de Esclerosis Múltiple)
| | - Adolfo López de Munain
- Neuroscience Area, Sensorial Neurodegeneration Group, Biodonostia Health Research Institute, San Sebastian, Spain.,Department of Neurology, Donostia University Hospital, San Sebastian, Spain.,Centro de Investigaciones Biomédicas en Red Sobre Enfermedades Neurodegenerativas, Instituto Carlos III, Ministerio de Economía y Competitividad, Spain.,Department of Neuroscience, University of the Basque Country, San Sebastian, Spain
| | - Javier Ruiz-Ederra
- Neuroscience Area, Sensorial Neurodegeneration Group, Biodonostia Health Research Institute, San Sebastian, Spain.,RETICS OFTARED, National Institute of Health Carlos III, Ministry of Economy and Competitiveness, Spain
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18
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Novel clinical findings in autosomal recessive NR2E3-related retinal dystrophy. Graefes Arch Clin Exp Ophthalmol 2018; 257:9-22. [PMID: 30324420 DOI: 10.1007/s00417-018-4161-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/01/2018] [Accepted: 10/03/2018] [Indexed: 02/07/2023] Open
Abstract
PURPOSE To evaluate the clinical phenotype of autosomal recessive NR2E3-related retinal dystrophy. METHODS We retrospectively studied 11 patients carrying out at least 2 NR2E3 mutations; they had undergone comprehensive ophthalmological examination, fundus photography, optical coherence tomography, electrophysiological testing, and visual field at the Regional Reference Center for Hereditary Retinal Degenerations of the Eye Clinic in Florence. RESULTS Five females and six males with a diagnosis of NR2E3-related retinal dystrophy were included in the study. All patients complained of nyctalopia. Visual acuity ranged from 0.00 logMAR to hand motion. Two patients presented bull's eye maculopathy, and one of these was characterized by a triple hyper-autofluorescent ring at the fundus autofluorescence examination. Three patients showed small yellowish dots and spots at the mid-periphery. One patient was characterized by widespread subretinal drusenoid deposits (SDD) at the posterior pole. Four patients showed vitreous abnormalities. Optical coherence tomography (OCT) examinations detected variable degrees of abnormal retinal lamination and schitic changes. Seven patients were compound heterozygous and four were homozygous for mutations in NR2E3. CONCLUSIONS Our study confirmed high variable phenotype in autosomal recessive NR2E3-related retinal dystrophy. Bull's eye maculopathy, subretinal drusenoid deposits, and foveal hypoplasia represent novel clinical findings in NR2E3-related retinal dystrophy. Macular involvement was detectable in all the patients, and the abnormal foveal avascular zone (FAZ) supports the role of NR2E3 in retinal development.
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19
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The nuclear hormone receptor gene Nr2c1 (Tr2) is a critical regulator of early retina cell patterning. Dev Biol 2017; 429:343-355. [DOI: 10.1016/j.ydbio.2017.05.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 02/08/2023]
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20
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Genetic characterization and disease mechanism of retinitis pigmentosa; current scenario. 3 Biotech 2017; 7:251. [PMID: 28721681 DOI: 10.1007/s13205-017-0878-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
Retinitis pigmentosa is a group of genetically transmitted disorders affecting 1 in 3000-8000 individual people worldwide ultimately affecting the quality of life. Retinitis pigmentosa is characterized as a heterogeneous genetic disorder which leads by progressive devolution of the retina leading to a progressive visual loss. It can occur in syndromic (with Usher syndrome and Bardet-Biedl syndrome) as well as non-syndromic nature. The mode of inheritance can be X-linked, autosomal dominant or autosomal recessive manner. To date 58 genes have been reported to associate with retinitis pigmentosa most of them are either expressed in photoreceptors or the retinal pigment epithelium. This review focuses on the disease mechanisms and genetics of retinitis pigmentosa. As retinitis pigmentosa is tremendously heterogeneous disorder expressing a multiplicity of mutations; different variations in the same gene might induce different disorders. In recent years, latest technologies including whole-exome sequencing contributing effectively to uncover the hidden genesis of retinitis pigmentosa by reporting new genetic mutations. In future, these advancements will help in better understanding the genotype-phenotype correlations of disease and likely to develop new therapies.
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21
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Li Y, Hao H, Swerdel MR, Cho HY, Lee KB, Hart RP, Lyu YL, Cai L. Top2b is involved in the formation of outer segment and synapse during late-stage photoreceptor differentiation by controlling key genes of photoreceptor transcriptional regulatory network. J Neurosci Res 2017; 95:1951-1964. [PMID: 28370415 DOI: 10.1002/jnr.24037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 01/17/2023]
Abstract
Topoisomerase II beta (Top2b) is an enzyme that alters the topologic states of DNA during transcription. Top2b deletion in early retinal progenitor cells causes severe defects in neural differentiation and affects cell survival in all retinal cell types. However, it is unclear whether the observed severe phenotypes are the result of cell-autonomous/primary defects or non-cell-autonomous/secondary defects caused by alterations of other retinal cells. Using photoreceptor cells as a model, we first characterized the phenotypes in Top2b conditional knockout. Top2b deletion leads to malformation of photoreceptor outer segments (OSs) and synapses accompanied by dramatic cell loss at late-stage photoreceptor differentiation. Then, we performed mosaic analysis with shRNA-mediated Top2b knockdown in neonatal retina using in vivo electroportation to target rod photoreceptors in neonatal retina. Top2b knockdown causes defective OS without causing a dramatic cell loss, suggesting a Top2b cell-autonomous function. Furthermore, RNA-seq analysis reveals that Top2b controls the expression of key genes in the photoreceptor gene-regulatory network (e.g., Crx, Nr2e3, Opn1sw, Vsx2) and retinopathy-related genes (e.g., Abca4, Bbs7, Pde6b). Together, our data establish a combinatorial cell-autonomous and non-cell-autonomous role for Top2b in the late stage of photoreceptor differentiation and maturation. © 2017 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Ying Li
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Hailing Hao
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
| | - Mavis R Swerdel
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Hyeon-Yeol Cho
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey
| | - Ki-Bum Lee
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey
| | - Yi Lisa Lyu
- Office of Research Commercialization, Rutgers University, Piscataway, New Jersey
| | - Li Cai
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey
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22
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Fulton J, Mazumder B, Whitchurch JB, Monteiro CJ, Collins HM, Chan CM, Clemente MP, Hernandez-Quiles M, Stewart EA, Amoaku WM, Moran PM, Mongan NP, Persson JL, Ali S, Heery DM. Heterodimers of photoreceptor-specific nuclear receptor (PNR/NR2E3) and peroxisome proliferator-activated receptor-γ (PPARγ) are disrupted by retinal disease-associated mutations. Cell Death Dis 2017; 8:e2677. [PMID: 28300834 PMCID: PMC5386588 DOI: 10.1038/cddis.2017.98] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 12/30/2022]
Abstract
Photoreceptor-specific nuclear receptor (PNR/NR2E3) and Tailless homolog (TLX/NR2E1) are human orthologs of the NR2E group, a subgroup of phylogenetically related members of the nuclear receptor (NR) superfamily of transcription factors. We assessed the ability of these NRs to form heterodimers with other members of the human NRs representing all major subgroups. The TLX ligand-binding domain (LBD) did not appear to form homodimers or interact directly with any other NR tested. The PNR LBD was able to form homodimers, but also exhibited robust interactions with the LBDs of peroxisome proliferator-activated receptor-γ (PPARγ)/NR1C3 and thyroid hormone receptor b (TRb) TRβ/NR1A2. The binding of PNR to PPARγ was specific for this paralog, as no interaction was observed with the LBDs of PPARα/NR1C1 or PPARδ/NR1C2. In support of these findings, PPARγ and PNR were found to be co-expressed in human retinal tissue extracts and could be co-immunoprecipitated as a native complex. Selected sequence variants in the PNR LBD associated with human retinopathies, or a mutation in the dimerization region of PPARγ LBD associated with familial partial lipodystrophy type 3, were found to disrupt PNR/PPARγ complex formation. Wild-type PNR, but not a PNR309G mutant, was able to repress PPARγ-mediated transcription in reporter assays. In summary, our results reveal novel heterodimer interactions in the NR superfamily, suggesting previously unknown functional interactions of PNR with PPARγ and TRβ that have potential importance in retinal development and disease.
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Affiliation(s)
- Joel Fulton
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | - Bismoy Mazumder
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | | | | | | | - Chun M Chan
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | | | | | - Elizabeth A Stewart
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - Winfried M Amoaku
- Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
| | - Paula M Moran
- School of Psychology, University of Nottingham, Nottingham, UK
| | - Nigel P Mongan
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham, UK
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA
| | - Jenny L Persson
- Division of Experimental Cancer Research, Department of Translational Medicine, Lund University, Clinical Research Centre, Malmö, Sweden
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Simak Ali
- Department of Surgery and Cancer, Imperial College London, London, UK
| | - David M Heery
- School of Pharmacy, University of Nottingham, Nottingham, UK
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23
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Ullah I, Kabir F, Iqbal M, Gottsch CBS, Naeem MA, Assir MZ, Khan SN, Akram J, Riazuddin S, Ayyagari R, Hejtmancik JF, Riazuddin SA. Pathogenic mutations in TULP1 responsible for retinitis pigmentosa identified in consanguineous familial cases. Mol Vis 2016; 22:797-815. [PMID: 27440997 PMCID: PMC4947966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 07/14/2016] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To identify pathogenic mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous familial cases. METHODS Seven large familial cases with multiple individuals diagnosed with retinitis pigmentosa were included in the study. Affected individuals in these families underwent ophthalmic examinations to document the symptoms and confirm the initial diagnosis. Blood samples were collected from all participating members, and genomic DNA was extracted. An exclusion analysis with microsatellite markers spanning the TULP1 locus on chromosome 6p was performed, and two-point logarithm of odds (LOD) scores were calculated. All coding exons along with the exon-intron boundaries of TULP1 were sequenced bidirectionally. We constructed a single nucleotide polymorphism (SNP) haplotype for the four familial cases harboring the K489R allele and estimated the likelihood of a founder effect. RESULTS The ophthalmic examinations of the affected individuals in these familial cases were suggestive of RP. Exclusion analyses confirmed linkage to chromosome 6p harboring TULP1 with positive two-point LOD scores. Subsequent Sanger sequencing identified the single base pair substitution in exon14, c.1466A>G (p.K489R), in four families. Additionally, we identified a two-base deletion in exon 4, c.286_287delGA (p.E96Gfs77*); a homozygous splice site variant in intron 14, c.1495+4A>C; and a novel missense variation in exon 15, c.1561C>T (p.P521S). All mutations segregated with the disease phenotype in the respective families and were absent in ethnically matched control chromosomes. Haplotype analysis suggested (p<10(-6)) that affected individuals inherited the causal mutation from a common ancestor. CONCLUSIONS Pathogenic mutations in TULP1 are responsible for the RP phenotype in seven familial cases with a common ancestral mutation responsible for the disease phenotype in four of the seven families.
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Affiliation(s)
- Inayat Ullah
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Firoz Kabir
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Muhammad Iqbal
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | | | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Zaman Assir
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Shaheen N. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan,Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California, San Diego, CA
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
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Kabir F, Ullah I, Ali S, Gottsch AD, Naeem MA, Assir MZ, Khan SN, Akram J, Riazuddin S, Ayyagari R, Hejtmancik JF, Riazuddin SA. Loss of function mutations in RP1 are responsible for retinitis pigmentosa in consanguineous familial cases. Mol Vis 2016; 22:610-25. [PMID: 27307693 PMCID: PMC4901054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 06/08/2016] [Indexed: 10/31/2022] Open
Abstract
PURPOSE This study was undertaken to identify causal mutations responsible for autosomal recessive retinitis pigmentosa (arRP) in consanguineous families. METHODS Large consanguineous families were ascertained from the Punjab province of Pakistan. An ophthalmic examination consisting of a fundus evaluation and electroretinography (ERG) was completed, and small aliquots of blood were collected from all participating individuals. Genomic DNA was extracted from white blood cells, and a genome-wide linkage or a locus-specific exclusion analysis was completed with polymorphic short tandem repeats (STRs). Two-point logarithm of odds (LOD) scores were calculated, and all coding exons and exon-intron boundaries of RP1 were sequenced to identify the causal mutation. RESULTS The ophthalmic examination showed that affected individuals in all families manifest cardinal symptoms of RP. Genome-wide scans localized the disease phenotype to chromosome 8q, a region harboring RP1, a gene previously implicated in the pathogenesis of RP. Sanger sequencing identified a homozygous single base deletion in exon 4: c.3697delT (p.S1233Pfs22*), a single base substitution in intron 3: c.787+1G>A (p.I263Nfs8*), a 2 bp duplication in exon 2: c.551_552dupTA (p.Q185Yfs4*) and an 11,117 bp deletion that removes all three coding exons of RP1. These variations segregated with the disease phenotype within the respective families and were not present in ethnically matched control samples. CONCLUSIONS These results strongly suggest that these mutations in RP1 are responsible for the retinal phenotype in affected individuals of all four consanguineous families.
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Affiliation(s)
- Firoz Kabir
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Inayat Ullah
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Shahbaz Ali
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | | | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Zaman Assir
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Shaheen N. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan,Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California, San Diego, CA
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD
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Dominant Retinitis Pigmentosa, p.Gly56Arg Mutation in NR2E3: Phenotype in a Large Cohort of 24 Cases. PLoS One 2016; 11:e0149473. [PMID: 26910043 PMCID: PMC4766102 DOI: 10.1371/journal.pone.0149473] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/31/2016] [Indexed: 11/20/2022] Open
Abstract
Importance This research is the single largest NR2E3 genotype-phenotype correlation study performed to date in autosomal dominant Retinitis Pigmentosa. Objective The aim of this study is to analyse the frequency of the p.Gly56Arg mutation in NR2E3 for the largest cohort of autosomal dominant Retinitis Pigmentosa patients to date and its associated phenotype. Patients and Methods A cohort of 201 unrelated Spanish families affected by autosomal dominant Retinitis Pigmentosa. The p.Gly56Arg mutation in the NR2E3 (NM_014249.2) gene was analysed in 201 families. In the 24 cases where the mutation had been detected, a haplotype analysis linked to the p.Gly56Arg families was performed, using four extragenic polymorphic markers D15S967, D15S1050, D15S204 and D15S188. Phenotype study included presence and age of onset of night blindness, visual field loss and cataracts; and an ophthalmoscopic examination after pupillary dilation and electroretinogram for the 24 cases. Results Seven of the 201 analyzed families were positive for the p.Gly56Arg, leading to a prevalence of 3.5%. Clinical data were available for 24 subjects. Night blindness was the first noticeable symptom (mean 15.9 years). Visual field loss onset was variable (23.3 ± 11.9 years). Loss of visual acuity appeared late in the disease´s evolution. Most of the patients with cataracts (50%) presented it from the third decade of life. Fundus changes showed inter and intrafamiliar variability, but most of the patients showed typical RP changes and it was common to find macular affectation (47.4%). Electroretinogram was impaired from the beginning of the disease. Two families shared a common haplotype. Additionally, all patients shared a 104Kb region between D15S1050 and the NR2E3 gene. Conclusions This study highlights the importance of p.Gly56Arg in the NR2E3 gene as a common mutation associated with adRP, and provides new clues to its phenotype, which can allow for a better clinical management and genetic counselling of patients and their families.
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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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von Alpen D, Tran HV, Guex N, Venturini G, Munier FL, Schorderet DF, Haider NB, Escher P. Differential dimerization of variants linked to enhanced S-cone sensitivity syndrome (ESCS) located in the NR2E3 ligand-binding domain. Hum Mutat 2015; 36:599-610. [PMID: 25703721 DOI: 10.1002/humu.22775] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 02/10/2015] [Indexed: 11/11/2022]
Abstract
NR2E3 encodes the photoreceptor-specific nuclear hormone receptor that acts as a repressor of cone-specific gene expression in rod photoreceptors, and as an activator of several rod-specific genes. Recessive variants located in the ligand-binding domain (LBD) of NR2E3 cause enhanced short wavelength sensitive- (S-) cone syndrome (ESCS), a retinal degeneration characterized by an excess of S-cones and non-functional rods. We analyzed the dimerization properties of NR2E3 and the effect of disease-causing LBD missense variants by bioluminescence resonance energy transfer (BRET(2) ) protein interaction assays. Homodimerization was not affected in presence of p.A256V, p.R039G, p.R311Q, and p.R334G variants, but abolished in presence of p.L263P, p.L336P, p.L353V, p.R385P, and p.M407K variants. Homology modeling predicted structural changes induced by NR2E3 LBD variants. NR2E3 LBD variants did not affect interaction with CRX, but with NRL and rev-erbα/NR1D1. CRX and NRL heterodimerized more efficiently together, than did either with NR2E3. NR2E3 did not heterodimerize with TLX/NR2E1 and RXRα/NR2C1. The identification of a new compound heterozygous patient with detectable rod function, who expressed solely the p.A256V variant protein, suggests a correlation between LBD variants able to form functional NR2E3 dimers and atypical mild forms of ESCS with residual rod function.
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Affiliation(s)
- Désirée von Alpen
- IRO-Institute for Research in Ophthalmology, Sion, Switzerland.,EPFL-Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Hoai Viet Tran
- Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Guex
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Francis L Munier
- Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | - Daniel F Schorderet
- IRO-Institute for Research in Ophthalmology, Sion, Switzerland.,EPFL-Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | - Neena B Haider
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute, Boston, Massachusetts
| | - Pascal Escher
- IRO-Institute for Research in Ophthalmology, Sion, Switzerland.,Jules-Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
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Avila-Fernandez A, Perez-Carro R, Corton M, Lopez-Molina MI, Campello L, Garanto A, Fernandez-Sanchez L, Duijkers L, Lopez-Martinez MA, Riveiro-Alvarez R, Da Silva LRJ, Sanchez-Alcudia R, Martin-Garrido E, Reyes N, Garcia-Garcia F, Dopazo J, Garcia-Sandoval B, Collin RW, Cuenca N, Ayuso C. Whole-exome sequencing reveals ZNF408 as a new gene associated with autosomal recessive retinitis pigmentosa with vitreal alterations. Hum Mol Genet 2015; 24:4037-48. [DOI: 10.1093/hmg/ddv140] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/13/2015] [Indexed: 12/20/2022] Open
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Zhi X, Zhou XE, He Y, Searose-Xu K, Zhang CL, Tsai CC, Melcher K, Xu HE. Structural basis for corepressor assembly by the orphan nuclear receptor TLX. Genes Dev 2015; 29:440-50. [PMID: 25691470 PMCID: PMC4335298 DOI: 10.1101/gad.254904.114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Zhi et al. report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. Mutations that weaken the TLX–Atrophin interaction compromise the repressive activity of TLX. In addition, mutations of corresponding residues in other members of this class of receptors diminish their repressor activities. The orphan nuclear receptor TLX regulates neural stem cell self-renewal in the adult brain and functions primarily as a transcription repressor through recruitment of Atrophin corepressors, which bind to TLX via a conserved peptide motif termed the Atro box. Here we report crystal structures of the human and insect TLX ligand-binding domain in complex with Atro box peptides. In these structures, TLX adopts an autorepressed conformation in which its helix H12 occupies the coactivator-binding groove. Unexpectedly, H12 in this autorepressed conformation forms a novel binding pocket with residues from helix H3 that accommodates a short helix formed by the conserved ALXXLXXY motif of the Atro box. Mutations that weaken the TLX–Atrophin interaction compromise the repressive activity of TLX, demonstrating that this interaction is required for Atrophin to confer repressor activity to TLX. Moreover, the autorepressed conformation is conserved in the repressor class of orphan nuclear receptors, and mutations of corresponding residues in other members of this class of receptors diminish their repressor activities. Together, our results establish the functional conservation of the autorepressed conformation and define a key sequence motif in the Atro box that is essential for TLX-mediated repression.
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Affiliation(s)
- Xiaoyong Zhi
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA; Autophagy Research Center,
| | - X Edward Zhou
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA
| | - Yuanzheng He
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA
| | - Kelvin Searose-Xu
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA
| | - Chun-Li Zhang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Texas 75390, USA
| | - Chih-Cheng Tsai
- Department of Cell Biology and Neuroscience, University of California at Riverside, Riverside, California 92521, USA
| | - Karsten Melcher
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA
| | - H Eric Xu
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA; Van Andel Research Institute-Shanghai Institute of Materia Medica (VARI/SIMM) Center, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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30
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Bates KE, Molnar J, Robinow S. The unfulfilled gene and nervous system development in Drosophila. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:217-23. [PMID: 24953188 DOI: 10.1016/j.bbagrm.2014.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 06/07/2014] [Accepted: 06/10/2014] [Indexed: 11/29/2022]
Abstract
The unfulfilled gene of Drosophila encodes a member of the NR2E subfamily of nuclear receptors. Like related members of the NR2E subfamily, UNFULFILLED is anticipated to function as a dimer, binding to DNA response elements and regulating the expression of target genes. The UNFULFILLED protein may be regulated by ligand-binding and may also be post-transcriptionally modified by sumoylation and phosphorylation. unfulfilled mutants display a range of aberrant phenotypes, problems with eclosion and post-eclosion behaviors, compromised fertility, arrhythmicity, and a lack of all adult mushroom body lobes. The locus of the fertility problem has not been determined. The behavioral arrhythmicity is due to the unfulfilled-dependent disruption of gene expression in a set of pacemaker neurons. The eclosion and the mushroom body lobe phenotypes of unfulfilled mutants are the result of developmental problems associated with failures in axon pathfinding or re-extension. Interest in genes that act downstream of unfulfilled has resulted in the identification of a growing number of unfulfilled interacting loci, providing the first glimpse into the composition of unfulfilled-dependent gene networks. This article is part of a Special Issue entitled: Nuclear receptors in animal development.
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Affiliation(s)
- Karen E Bates
- Department of Biology, University of Hawaii, Honolulu, HI 96822, USA
| | - Janos Molnar
- Department of Biology, University of Hawaii, Honolulu, HI 96822, USA
| | - Steven Robinow
- Department of Biology, University of Hawaii, Honolulu, HI 96822, USA.
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31
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Roosing S, Thiadens AAHJ, Hoyng CB, Klaver CCW, den Hollander AI, Cremers FPM. Causes and consequences of inherited cone disorders. Prog Retin Eye Res 2014; 42:1-26. [PMID: 24857951 DOI: 10.1016/j.preteyeres.2014.05.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 04/29/2014] [Accepted: 05/06/2014] [Indexed: 11/18/2022]
Abstract
Hereditary cone disorders (CDs) are characterized by defects of the cone photoreceptors or retinal pigment epithelium underlying the macula, and include achromatopsia (ACHM), cone dystrophy (COD), cone-rod dystrophy (CRD), color vision impairment, Stargardt disease (STGD) and other maculopathies. Forty-two genes have been implicated in non-syndromic inherited CDs. Mutations in the 5 genes implicated in ACHM explain ∼93% of the cases. On the contrary, only 21% of CRDs (17 genes) and 25% of CODs (8 genes) have been elucidated. The fact that the large majority of COD and CRD-associated genes are yet to be discovered hints towards the existence of unknown cone-specific or cone-sensitive processes. The ACHM-associated genes encode proteins that fulfill crucial roles in the cone phototransduction cascade, which is the most frequently compromised (10 genes) process in CDs. Another 7 CD-associated proteins are required for transport processes towards or through the connecting cilium. The remaining CD-associated proteins are involved in cell membrane morphogenesis and maintenance, synaptic transduction, and the retinoid cycle. Further novel genes are likely to be identified in the near future by combining large-scale DNA sequencing and transcriptomics technologies. For 31 of 42 CD-associated genes, mammalian models are available, 14 of which have successfully been used for gene augmentation studies. However, gene augmentation for CDs should ideally be developed in large mammalian models with cone-rich areas, which are currently available for only 11 CD genes. Future research will aim to elucidate the remaining causative genes, identify the molecular mechanisms of CD, and develop novel therapies aimed at preventing vision loss in individuals with CD in the future.
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Affiliation(s)
- Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | | | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Caroline C W Klaver
- Department of Ophthalmology Erasmus Medical Centre, 3000 CA, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus Medical Centre, 3000 CA, Rotterdam, The Netherlands
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Department of Ophthalmology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Modifier genes as therapeutics: the nuclear hormone receptor Rev Erb alpha (Nr1d1) rescues Nr2e3 associated retinal disease. PLoS One 2014; 9:e87942. [PMID: 24498227 PMCID: PMC3909326 DOI: 10.1371/journal.pone.0087942] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/30/2013] [Indexed: 11/19/2022] Open
Abstract
Nuclear hormone receptors play a major role in many important biological processes. Most nuclear hormone receptors are ubiquitously expressed and regulate processes such as metabolism, circadian function, and development. They function in these processes to maintain homeostasis through modulation of transcriptional gene networks. In this study we evaluate the effectiveness of a nuclear hormone receptor gene to modulate retinal degeneration and restore the integrity of the retina. Currently, there are no effective treatment options for retinal degenerative diseases leading to progressive and irreversible blindness. In this study we demonstrate that the nuclear hormone receptor gene Nr1d1 (Rev-Erbα) rescues Nr2e3-associated retinal degeneration in the rd7 mouse, which lacks a functional Nr2e3 gene. Mutations in human NR2E3 are associated with several retinal degenerations including enhanced S cone syndrome and retinitis pigmentosa. The rd7 mouse, lacking Nr2e3, exhibits an increase in S cones and slow, progressive retinal degeneration. A traditional genetic mapping approach previously identified candidate modifier loci. Here, we demonstrate that in vivo delivery of the candidate modifier gene, Nr1d1 rescues Nr2e3 associated retinal degeneration. We observed clinical, histological, functional, and molecular restoration of the rd7 retina. Furthermore, we demonstrate that the mechanism of rescue at the molecular and functional level is through the re-regulation of key genes within the Nr2e3-directed transcriptional network. Together, these findings reveal the potency of nuclear receptors as modulators of disease and specifically of NR1D1 as a novel therapeutic for retinal degenerations.
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Schorderet DF, Bernasconi M, Tiab L, Favez T, Escher P. IROme, a new high-throughput molecular tool for the diagnosis of inherited retinal dystrophies-a price comparison with Sanger sequencing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:171-6. [PMID: 24664695 DOI: 10.1007/978-1-4614-3209-8_22] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The molecular diagnosis of retinal dystrophies (RD) is difficult because of genetic and clinical heterogeneity. Previously, the molecular screening of genes was done one by one, sometimes in a scheme based on the frequency of sequence variants and the number of exons/length of the candidate genes. Payment for these procedures was complicated and the sequential billing of several genes created endless paperwork. We therefore evaluated the costs of generating and sequencing a hybridization-based DNA library enriched for the 64 most frequently mutated genes in RD, called IROme, and compared them to the costs of amplifying and sequencing these genes by the Sanger method. The production cost generated by the high-throughput (HT) sequencing of IROme was established at CHF 2,875.75 per case. Sanger sequencing of the same exons cost CHF 69,399.02. Turnaround time of the analysis was 3 days for IROme. For Sanger sequencing, it could only be estimated, as we never sequenced all 64 genes in one single patient. Sale cost for IROme calculated on the basis of the sale cost of one exon by Sanger sequencing is CHF 8,445.88, which corresponds to the sale price of 40 exons. In conclusion, IROme is cheaper and faster than Sanger sequencing and therefore represents a sound approach for the diagnosis of RD, both scientifically and economically. As a drop in the costs of HT sequencing is anticipated, target resequencing might become the new gold standard in the molecular diagnosis of RD.
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Affiliation(s)
- Daniel F Schorderet
- IRO, Institute for Research in Ophthalmology, 64 Avenue du Grand-Champsec, 1950, Sion, Switzerland,
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Park SP, Hong IH, Tsang SH, Lee W, Horowitz J, Yzer S, Allikmets R, Chang S. Disruption of the human cone photoreceptor mosaic from a defect in NR2E3 transcription factor function in young adults. Graefes Arch Clin Exp Ophthalmol 2013; 251:2299-309. [PMID: 23604511 PMCID: PMC4291322 DOI: 10.1007/s00417-013-2296-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 02/19/2013] [Accepted: 02/24/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Enhanced S-cone syndrome is an orphan disease caused by mutations in the NR2E3 gene which result in an increased number of S-cones overpopulating the retina. Although the characteristic onset of enhanced S-cone syndrome can be well-documented by current ophthalmic imaging modalities, techniques such as spectral-domain optical coherence tomography (SD-OCT) and scanning laser ophthalmoscopy (SLO) fail to provide sufficient details regarding the microstructure of photoreceptors in retinal diseases. Adaptive optics (AO) provides a unique opportunity to analyze the effects of genetic mutations on photoreceptors by compensating aberrations of human eyes. METHODS Three eyes of three young adults with enhanced S-cone syndrome were studied by clinical examination, genetic screening, fundus autofluorescence (FAF) imaging, SD-OCT, and electroretinography (ERG). Cone mosaic imaging was accomplished by an AO-SLO equipped with a dual crystal on silicon spatial light modulator. Qualitative image analyses and genetic findings were investigated in each patient. RESULTS The diagnosis of patients was confirmed by ERG finding. Genetic screening confirmed the presence of two disease-causing mutations in the NR2E3 gene in each study patient, as well as identified a novel mutation (202 A > G, S68G). Fundus photograph, FAF, and SD-OCT found rosette-like lesion within the mid-periphery along the vascular arcades of the retina. In all AO-SLO images of patients, sparse distribution and asymmetric size of cone mosaic pattern were found within central retina. There were regions of dark space between groups of photoreceptors, distinguishable from shadowing and artifacts. CONCLUSIONS AO-SLO provided an in-depth window into the retina of live enhanced S-cone syndrome patients beyond the ability of other current imaging modalities. Dark lesions within the central retina in each patient contain structurally dysfunctional cones which account for retinal mosaic disorganization, and may predispose affected areas to other abnormalities such as rosette lesions. AO-SLO can be an efficient diagnostic tool in clinics for examining cellular-level pathologies in various retinal dystrophies.
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Affiliation(s)
- Sung Pyo Park
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Ophthalmology, Kangdong Sacred Heart Hospital, Hallym University Medical Center, Seoul, South Korea
| | - In Hwan Hong
- Department of Ophthalmology, Kangdong Sacred Heart Hospital, Hallym University Medical Center, Seoul, South Korea
| | - Stephen H. Tsang
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
- Departments of Ophthalmology, Pathology and Cell Biology, Edward S. Harkness Eye Institute, Columbia University, 635 west 165th street, New York, NY 10032, USA
| | - Winston Lee
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Jason Horowitz
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | | | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Pathology & Cell Biology, Columbia University, New York, NY, USA
| | - Stanley Chang
- Department of Ophthalmology, Columbia University, New York, NY, USA
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Systematic analyses of the cytotoxic effects of compound 11a, a putative synthetic agonist of photoreceptor-specific nuclear receptor (PNR), in cancer cell lines. PLoS One 2013; 8:e75198. [PMID: 24066170 PMCID: PMC3774666 DOI: 10.1371/journal.pone.0075198] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 08/11/2013] [Indexed: 12/19/2022] Open
Abstract
Photoreceptor cell-specific receptor (PNR/NR2E3) is an orphan nuclear receptor that plays a critical role in retinal development and photoreceptor maintenance. The disease-causing mutations in PNR have a pleiotropic effect resulting in varying retinal diseases. Recently, PNR has been implicated in control of cellular functions in cancer cells. PNR was reported to be a novel regulator of ERα expression in breast cancer cells, and high PNR expression correlates with favorable response to tamoxifen treatment. Moreover, PNR was shown to increase p53 stability in HeLa cells, implying that PNR may be a therapeutic target in this and other cancers that retain a wild type p53 gene. To facilitate further understanding of PNR functions in cancer, we characterized compound 11a, a synthetic, putative PNR agonist in several cell-based assays. Interestingly, we showed that 11a failed to activate PNR and its cytotoxicity was independent of PNR expression, excluding PNR as a mediator for 11a cytotoxicity. Systematic analyses of the cytotoxic effects of 11a in NCI-60 cell lines revealed a strong positive correlation of cytotoxicity with p53 status, i.e., p53 wild type cell lines were significantly more sensitive to 11a than p53 mutated or null cell lines. Furthermore, using HCT116 p53+/+ and p53-/- isogenic cell lines we revealed that the mechanism of 11a-induced cytotoxicity occurred through G1/S phase cell cycle arrest rather than apoptosis. In conclusion, we observed a correlation of 11a sensitivity with p53 status but not with PNR expression, suggesting that tumors expressing wild type p53 might be responsive to this compound.
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Chan CM, Fulton J, Montiel-Duarte C, Collins HM, Bharti N, Wadelin FR, Moran PM, Mongan NP, Heery DM. A signature motif mediating selective interactions of BCL11A with the NR2E/F subfamily of orphan nuclear receptors. Nucleic Acids Res 2013; 41:9663-79. [PMID: 23975195 PMCID: PMC3834829 DOI: 10.1093/nar/gkt761] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Despite their physiological importance, selective interactions between nuclear receptors (NRs) and their cofactors are poorly understood. Here, we describe a novel signature motif (F/YSXXLXXL/Y) in the developmental regulator BCL11A that facilitates its selective interaction with members of the NR2E/F subfamily. Two copies of this motif (named here as RID1 and RID2) permit BCL11A to bind COUP-TFs (NR2F1;NR2F2;NR2F6) and Tailless/TLX (NR2E1), whereas RID1, but not RID2, binds PNR (NR2E3). We confirmed the existence of endogenous BCL11A/TLX complexes in mouse cortex tissue. No interactions of RID1 and RID2 with 20 other ligand-binding domains from different NR subtypes were observed. We show that RID1 and RID2 are required for BCL11A-mediated repression of endogenous γ-globin gene and the regulatory non-coding transcript Bgl3, and we identify COUP-TFII binding sites within the Bgl3 locus. In addition to their importance for BCL11A function, we show that F/YSXXLXXL/Y motifs are conserved in other NR cofactors. A single FSXXLXXL motif in the NR-binding SET domain protein NSD1 facilitates its interactions with the NR2E/F subfamily. However, the NSD1 motif incorporates features of both LXXLL and FSXXLXXL motifs, giving it a distinct NR-binding pattern in contrast to other cofactors. In summary, our results provide new insights into the selectivity of NR/cofactor complex formation.
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Affiliation(s)
- Chun Ming Chan
- Gene Regulation Group, Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, UK, School of Psychology, University of Nottingham, Nottingham NG7 2RD, UK and School of Veterinary Medicine and Science, University of Nottingham, Nottingham NG7 2RD, UK
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Abstract
PURPOSE To review three inherited retinal disorders associated with diagnostic or pathognomonic electroretinogram (ERG) abnormalities: cone dystrophy with supernormal rod ERG (KCNV2), enhanced S-cone syndrome (NR2E3), and bradyopsia (RGS9/R9AP). METHODS A review of clinical details, genetic basis, and electrophysiological features in these disorders and a brief summary of the standard and nonstandard ERG techniques required to identify the disorders. RESULTS The electrophysiological features in each of these three disorders are pathognomonic such that the responsible gene can be specified. The results from nonstandard electrophysiological testing in excess of international standards are necessary to describe the pathognomonic changes in cone dystrophy with supernormal rod ERG and bradyopsia. The clinical phenotype in the disorders can be variable. Mutations in NR2E3 may additionally be associated with phenotypes other than enhanced S-cone syndrome. CONCLUSION : Characteristic ERG changes enable the diagnosis of cone dystrophy with supernormal rod ERG, enhanced S-cone syndrome, and bradyopsia and accurate genetic screening. This review highlights the need for additional nonstandard ERGs to make the diagnosis in two of these disorders.
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Dias MDS, Hernan I, Pascual B, Borràs E, Mañé B, Gamundi MJ, Carballo M. Detection of novel mutations that cause autosomal dominant retinitis pigmentosa in candidate genes by long-range PCR amplification and next-generation sequencing. Mol Vis 2013; 19:654-64. [PMID: 23559859 PMCID: PMC3611935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/19/2013] [Indexed: 10/27/2022] Open
Abstract
PURPOSE To devise an effective method for detecting mutations in 12 genes (CA4, CRX, IMPDH1, NR2E3, RP9, PRPF3, PRPF8, PRPF31, PRPH2, RHO, RP1, and TOPORS) commonly associated with autosomal dominant retinitis pigmentosa (adRP) that account for more than 95% of known mutations. METHODS We used long-range PCR (LR-PCR) amplification and next-generation sequencing (NGS) performed in a GS Junior 454 benchtop sequencing platform. Twenty LR-PCR fragments, between 3,000 and 10,000 bp, containing all coding exons and flanking regions of the 12 genes, were obtained from DNA samples of patients with adRP. Sequencing libraries were prepared with an enzymatic (Fragmentase technology) method. RESULTS Complete coverage of the coding and flanking sequences of the 12 genes assayed was obtained with NGS, with an average sequence depth of 380× (ranging from 128× to 1,077×). Five previous known mutations in the adRP genes were detected with a sequence variation percentage between 35% and 65%. We also performed a parallel sequence analysis of four samples, three of them new patients with index adRP, in which two novel mutations were detected in RHO (p.Asn73del) and PRPF31 (p.Ile109del). CONCLUSIONS The results demonstrate that genomic LR-PCR amplification together with NGS is an effective method for analyzing individual patient samples for mutations in a monogenic heterogeneous disease such as adRP. This approach proved effective for the parallel analysis of adRP and has been introduced as routine. Additionally, this approach could be extended to other heterogeneous genetic diseases.
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Corso-Díaz X, Borrie AE, Bonaguro R, Schuetz JM, Rosenberg T, Jensen H, Brooks BP, MacDonald IM, Pasutto F, Walter MA, Grønskov K, Brooks-Wilson A, Simpson EM. Absence of NR2E1 mutations in patients with aniridia. Mol Vis 2012; 18:2770-82. [PMID: 23213277 PMCID: PMC3513187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 11/20/2012] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Nuclear receptor 2E1 (NR2E1) is a transcription factor with many roles during eye development and thus may be responsible for the occurrence of certain congenital eye disorders in humans. To test this hypothesis, we screened NR2E1 for candidate mutations in patients with aniridia and other congenital ocular malformations (anterior segment dysgenesis, congenital optic nerve malformation, and microphthalmia). METHODS The NR2E1 coding region, 5' and 3' untranslated regions (UTRs), exon flanking regions including consensus splice sites, and six evolutionarily conserved non-coding candidate regulatory regions were analyzed by sequencing 58 probands with aniridia of whom 42 were negative for PAX6 mutations. Nineteen probands with anterior segment dysgenesis, one proband with optic nerve malformation, and two probands with microphthalmia were also sequenced. The control population comprised 376 healthy individuals. All sequences were analyzed against the GenBank sequence AL078596.8 for NR2E1. In addition, the coding region and flanking intronic sequences of FOXE3, FOXC1, PITX2, CYP1B1, PAX6, and B3GALTL were sequenced in one patient and his relatives. RESULTS Sequencing analysis showed 17 NR2E1 variants including two novel rare non-coding variants (g.-1507G>A, g.14258C>T), and one novel rare coding variant (p.Arg274Gly). The latter was present in a male diagnosed with Peters' anomaly who subsequently was found to have a known causative mutation for Peters' plus syndrome in B3GALTL (c.660+1G>A). In addition, the NR2E1 novel rare variant Arg274Gly was present in the unaffected mother of the patient but absent in 746 control chromosomes. CONCLUSIONS We eliminated a major role for NR2E1 regulatory and coding mutations in aniridia and found a novel rare coding variant in NR2E1. In addition, we found no coding region variation in the control population for NR2E1, which further supports its previously reported high level of conservation and low genetic diversity. Future NR2E1 studies in ocular disease groups such as those involving retinal and optic nerve abnormalities should be undertaken to determine whether NR2E1 plays a role in these conditions.
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Affiliation(s)
- Ximena Corso-Díaz
- Centre for Molecular Medicine and Therapeutics at the Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada,Genetics Graduate Program, University of British Columbia, Vancouver, BC, Canada
| | - Adrienne E. Borrie
- Centre for Molecular Medicine and Therapeutics at the Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada,Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Russell Bonaguro
- Centre for Molecular Medicine and Therapeutics at the Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Johanna M. Schuetz
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada,Canada’s Michael Smith’s Genome Sciences Centre, BC Cancer Agency, Vancouver, BC, Canada
| | - Thomas Rosenberg
- National Eye Clinic for the Visually Impaired, The Kennedy Center, Glostrup, Denmark
| | - Hanne Jensen
- National Eye Clinic for the Visually Impaired, The Kennedy Center, Glostrup, Denmark,Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Glostrup, Denmark
| | - Brian P. Brooks
- National Eye Institute, National Institute of Health, Bethesda, Maryland, United States of America
| | - Ian M. MacDonald
- Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Francesca Pasutto
- Institute of Human Genetics, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Michael A. Walter
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Karen Grønskov
- Center for Applied Human Molecular Genetics, The Kennedy Center, Rigshospitalet, Glostrup, Denmark,Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Angela Brooks-Wilson
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada,Canada’s Michael Smith’s Genome Sciences Centre, BC Cancer Agency, Vancouver, BC, Canada,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Elizabeth M. Simpson
- Centre for Molecular Medicine and Therapeutics at the Child & Family Research Institute, University of British Columbia, Vancouver, BC, Canada,Genetics Graduate Program, University of British Columbia, Vancouver, BC, Canada,Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada,Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
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Qin Q, Knapinska A, Dobri N, Madoux F, Chase P, Hodder P, Petrukhin K. In pursuit of synthetic modulators for the orphan retina-specific nuclear receptor NR2E3. J Ocul Pharmacol Ther 2012; 29:298-309. [PMID: 23098562 DOI: 10.1089/jop.2012.0135] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE NR2E3 is an orphan nuclear receptor expressed exclusively in photoreceptor cells of the retina. NR2E3-specific modulators may prolong photoreceptor survival in patients with dry age-related macular degeneration and other forms of retinal degeneration. To definitively establish NR2E3 as a photoreceptor protection target, identification of small-molecule NR2E3 modulators and their testing in animal models of retinal degeneration are required. Development of the high-throughput screen (HTS)-compatible screen for small-molecule NR2E3 modulators is the first step toward this goal. METHODS Purification protocol for isolation of the functionally competent soluble NR2E3 protein after its expression in the insect Sf9 cells was developed. The time-resolved fluorescence energy-transfer (TR-FRET) assay assessing agonist-sensitive interaction between apo-NR2E3 and transcriptional corepressor RetCOR was used for characterization of the previously reported putative NR2E3 agonist, Compound 11a, and to conduct the HTS for novel small-molecule NR2E3 modulators (direct and inverse agonists). A counterscreen TR-FRET assay that measures the affect of test compounds on PPARγ interaction with corepressor NCOR was used for assessing the specificity of compounds identified in the HTS. RESULTS We developed the cell-free TR-FRET assay for small-molecule NR2E3 modulators, which is based on agonist-induced disruption of the interaction between GST-tagged apo-NR2E3 and MBP-tagged fragment of transcriptional corepressor RetCOR. Compound 11a, a putative NR2E3 agonist, did not affect the NR2E3-RetCOR interaction, as was established by its titration in the developed assay. The assay was miniaturized for an ultralow-volume 1,536-well format and automated into 3 simple pipetting steps. Consistent with excellent assay performance, the test runs established a Z'-score within the 0.6-0.8 range. Analysis of the mid-size National Institutes of Health collection of 315,001 structurally diverse drug-like compounds confirmed excellent assay performance, but did not reveal NR2E3-specific agonists or inverse agonists. CONCLUSIONS A robust and reliable TR-FRET assay for small-molecule NR2E3-specific modulators suitable for the analysis of million compound-strong HTS libraries was developed. A previously described putative NR2E3 agonist, Compound 11a, is unlikely to represent a direct NR2E3 agonist. Application of the developed assay for screening of a more abundant and diverse compound collection be required for identification of synthetic NR2E3 ligands.
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Affiliation(s)
- Qiong Qin
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032, USA
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Cheng H, Khan NW, Roger JE, Swaroop A. Excess cones in the retinal degeneration rd7 mouse, caused by the loss of function of orphan nuclear receptor Nr2e3, originate from early-born photoreceptor precursors. Hum Mol Genet 2011; 20:4102-15. [PMID: 21813656 DOI: 10.1093/hmg/ddr334] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The orphan nuclear receptor NR2E3 is a direct transcriptional target of NRL, the key basic motif leucine zipper transcription factor that dictates rod versus cone photoreceptor cell fate in the mammalian retina. The lack of NR2E3 function in humans and in retinal degeneration rd7 mutant mouse leads to increased S-cones accompanied by rod degeneration, whereas ectopic expression of Nr2e3 in the cone-only Nrl(-/-) retina generates rod-like cells that do not exhibit any visual function. Using GFP to tag the newborn rods and by 5-bromo-2'-deoxyuridine birthdating, we demonstrate that early-born post-mitotic photoreceptor precursors in the rd7 retina express cone-specific genes. Transgenic mouse studies in the rd7 background show that Nr2e3 when expressed under the control of Crx promoter can restore rod photoreceptor function and suppress cone gene expression. Furthermore, Nr2e3 expression in photoreceptor precursors committed to be rods (driven by the Nrl promoter) could completely rescue the retinal phenotype of the rd7 mice. We conclude that excess of S-cones in the rd7 retina originate from photoreceptor precursors with a 'default' fate and not from proliferation of cones and that Nr2e3 is required to suppress the expression of S-cone genes during normal rod differentiation. These studies further support the 'transcriptional dominance' model of photoreceptor cell fate determination and provide insights into the pathogenesis of retinal disease phenotypes caused by NR2E3 mutations.
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Affiliation(s)
- Hong Cheng
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA
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Yuan Y, Zhou X, Wang F, Yan M, Ding F. Evidence for a novel autosomal dominant retinitis pigmentosa linked to chromosome 1p22.1-q12 in a Chinese family. Curr Eye Res 2011; 36:154-67. [PMID: 21281067 DOI: 10.3109/02713683.2010.511393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To identify the causative genetic locus in a Chinese autosomal dominant retinitis pigmentosa (adRP) family that contained seven affected members in three generations. METHODS After clinical diagnosis and exclusion of all mapped genes and loci, the SLINK program was used to simulate the maximum logarithm of the likelihood ratio (LOD) score for a linkage study in this small family. A genome-wide scan was performed using microsatellite markers at 10 cM intervals. Two-point and multipoint LOD scores were calculated, and haplotypes were constructed. RESULTS The H11 family clinical presentation included an early onset of night blindness, a progressive loss of the peripheral visual field, typical retinitis pigmentosa (RP) fundus changes, and a cataract complication. A maximum two-point LOD score of 2.54 (θ = 0) was found at markers D1S2739, D1S457, D1S187, D1S189, and D1S305, and multipoint linkage analysis yielded a maximum LOD score of 2.54 for marker D1S187. These LOD scores were the closest to the maximum simulated LOD score. Haplotype analysis revealed that this form of adRP segregates with a 38.25 cM region that spanned 50 Mb on chromosome 1p22.1-q12. CONCLUSIONS Although this locus overlaps the RP19 locus caused by mutations in ABCA4 and the RP32 locus, both are inherited in an autosomal recessive mode rather than the autosomal dominant mode of inheritance found in the H11 family. The identification of this potential new locus for adRP further confirms the high level of heterogeneity for RP.
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Affiliation(s)
- Yuan Yuan
- Center for Gene Diagnosis, Zhongnan Hospital, Wuhan University, Wuhan, China
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Nuclear receptor Rev-erb alpha (Nr1d1) functions in concert with Nr2e3 to regulate transcriptional networks in the retina. PLoS One 2011; 6:e17494. [PMID: 21408158 PMCID: PMC3050883 DOI: 10.1371/journal.pone.0017494] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 02/07/2011] [Indexed: 12/23/2022] Open
Abstract
The majority of diseases in the retina are caused by genetic mutations affecting the development and function of photoreceptor cells. The transcriptional networks directing these processes are regulated by genes such as nuclear hormone receptors. The nuclear hormone receptor gene Rev-erb alpha/Nr1d1 has been widely studied for its role in the circadian cycle and cell metabolism, however its role in the retina is unknown. In order to understand the role of Rev-erb alpha/Nr1d1 in the retina, we evaluated the effects of loss of Nr1d1 to the developing retina and its co-regulation with the photoreceptor-specific nuclear receptor gene Nr2e3 in the developing and mature retina. Knock-down of Nr1d1 expression in the developing retina results in pan-retinal spotting and reduced retinal function by electroretinogram. Our studies show that NR1D1 protein is co-expressed with NR2E3 in the outer neuroblastic layer of the developing mouse retina. In the adult retina, NR1D1 is expressed in the ganglion cell layer and is co-expressed with NR2E3 in the outer nuclear layer, within rods and cones. Several genes co-targeted by NR2E3 and NR1D1 were identified that include: Nr2c1, Recoverin, Rgr, Rarres2, Pde8a, and Nupr1. We examined the cyclic expression of Nr1d1 and Nr2e3 over a twenty-four hour period and observed that both nuclear receptors cycle in a similar manner. Taken together, these studies reveal a novel role for Nr1d1, in conjunction with its cofactor Nr2e3, in regulating transcriptional networks critical for photoreceptor development and function.
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Udar N, Small K, Chalukya M, Silva-Garcia R, Marmor M. Developmental or degenerative--NR2E3 gene mutations in two patients with enhanced S cone syndrome. Mol Vis 2011; 17:519-25. [PMID: 21364904 PMCID: PMC3044695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 02/14/2011] [Indexed: 11/05/2022] Open
Abstract
PURPOSE Enhanced S Cone Syndrome is a rare autosomal recessive disorder characterized clinically by an absence of rod function, a replacement of most L and M cone function by S cone activity (Goldmann-Favre Syndrome) and by variable degrees of retinal degeneration in different families. The causative gene, nuclear receptor subfamily 2, group E, member 3 (NR2E3), controls the developmental sequence for rods and cones. The purpose of this study was to compare the nature and implications of mutations in two subjects with Enhanced S Cone Syndrome who have significantly different degrees of degenerative damage. METHODS A direct sequencing approach was used to identify the mutations. Genomic DNA was amplified from all the exons of NR2E3 and used as a template for sequencing. Of the two families studied, Case 1 is of Persian ethnicity while Case 2 is Brazilian. A total of six individuals within the two families were studied. RESULTS Case 1 (original propositus of the syndrome) has the characteristic developmental rod/cone abnormality with large amplitude electroretinogram responses and no retinal degeneration. She was homozygous for a novel mutation, c.[del196-201del6] (p.G66-C67del), which lies entirely within the P-box for this gene. By comparison, Case 2 had Goldmann-Favre Syndrome with retinal degeneration and low electroretinogram signals. She was a compound heterozygote for c.[119-2A>C]+[del194-202del9] (p.N65-C67del), mutations that have been reported previously. Her second mutation overlaps that of Case 1 within the P-box. CONCLUSIONS The novel in-frame homozygous deletion of Case 1, within the P-box motif of the DNA binding domain, caused a developmental abnormality without retinal degeneration. Case 2, with more traditional Goldmann-Favre Syndrome with retinal degeneration, was a compound heterozygote where one allele had a similar P-box deletion but the other was a splicing defect. Case 1 is the first reported homozygous deletion within the P-box. This is the first report of NR2E3 mutations in a Persian and a Brazilian family.
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Affiliation(s)
- Nitin Udar
- Department of Ophthalmology, University of California Irvine, Irvine, CA
| | - Kent Small
- Molecular Insight LLC, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Meenal Chalukya
- Department of Hematology and Oncology, University of California Los Angeles, Los Angeles, CA
| | | | - Michael Marmor
- Department of Ophthalmology, Stanford University Medical Center, Stanford, CA
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A novel mutation (Cys83Tyr) in the second zinc finger of NR2E3 in enhanced S-cone syndrome. Graefes Arch Clin Exp Ophthalmol 2010; 249:201-8. [PMID: 20725840 DOI: 10.1007/s00417-010-1482-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 07/25/2010] [Accepted: 07/26/2010] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND Enhanced S-cone syndrome (ESCS) is an autosomal recessive retinal disorder characterized by an increased number of S-cones over L/M cones and rods. Mutations in the NR2E3 gene, encoding a photoreceptor-specific nuclear receptor, are identified in patients with ESCS. The purpose of this study is to report the ophthalmic features of a 25-year-old Portuguese male with a typical ESCS phenotype and a novel homozygous NR2E3 mutation. METHODS The patient underwent a detailed ophthalmic examination including fundus photography, fluorescein angiography (FAF), fundus autofluorescence imaging (FAI), and spectral domain optical coherence tomography (SD-OCT). Full-field electroretinography (ERG), S-cone ERG, and multifocal ERG were performed. Mutation screening of the NR2E3 gene was performed with polymerase chain reaction amplification and direct sequencing. RESULTS The patient had poor visual acuity but good color vision. Funduscopy showed degenerative changes from the vascular arcades to the midperipheral retina. The SD-OCT revealed macular schisis and cystoid changes that had no fluorescein leakage. The posterior pole showed diffusely increased autofluorescence compared with eccentric areas in both eyes. International-standard full-field ERG showed the typical pathognomonic changes associated with ESCS and the short-wavelength flash ERG was simplified, delayed, and similar to the standard photopic flash ERG. Multifocal ERG showed widespread delay and reduction. Genetic analysis revealed a novel homozygous mutation (p.C83Y), which resides in the second zinc finger of the DNA-binding domain. CONCLUSIONS This homozygous mutation is likely to affect binding to target DNA sites, resulting in a non-functional behavior of NR2E3 protein. It is associated with a typical form of ESCS with a nondetectable rod response and reduced/delayed mfERG responses at all eccentricities.
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Current World Literature. Curr Opin Ophthalmol 2010; 21:239-46. [DOI: 10.1097/icu.0b013e32833983a3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Schorderet DF, Escher P. NR2E3 mutations in enhanced S-cone sensitivity syndrome (ESCS), Goldmann-Favre syndrome (GFS), clumped pigmentary retinal degeneration (CPRD), and retinitis pigmentosa (RP). Hum Mutat 2010; 30:1475-85. [PMID: 19718767 DOI: 10.1002/humu.21096] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
NR2E3, also called photoreceptor-specific nuclear receptor (PNR), is a transcription factor of the nuclear hormone receptor superfamily whose expression is uniquely restricted to photoreceptors. There, its physiological activity is essential for proper rod and cone photoreceptor development and maintenance. Thirty-two different mutations in NR2E3 have been identified in either homozygous or compound heterozygous state in the recessively inherited enhanced S-cone sensitivity syndrome (ESCS), Goldmann-Favre syndrome (GFS), and clumped pigmentary retinal degeneration (CPRD). The clinical phenotype common to all these patients is night blindness, rudimental or absent rod function, and hyperfunction of the "blue" S-cones. A single p.G56R mutation is inherited in a dominant manner and causes retinitis pigmentosa (RP). We have established a new locus-specific database for NR2E3 (www.LOVD.nl/eye), containing all reported mutations, polymorphisms, and unclassified sequence variants, including novel ones. A high proportion of mutations are located in the evolutionarily-conserved DNA-binding domains (DBDs) and ligand-binding domains (LBDs) of NR2E3. Based on homology modeling of these NR2E3 domains, we propose a structural localization of mutated residues. The high variability of clinical phenotypes observed in patients affected by NR2E3-linked retinal degenerations may be caused by different disease mechanisms, including absence of DNA-binding, altered interactions with transcriptional coregulators, and differential activity of modifier genes.
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Kanda A, Swaroop A. A comprehensive analysis of sequence variants and putative disease-causing mutations in photoreceptor-specific nuclear receptor NR2E3. Mol Vis 2009; 15:2174-84. [PMID: 19898638 PMCID: PMC2773741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 10/19/2009] [Indexed: 11/01/2022] Open
Abstract
PURPOSE The photoreceptor-specific orphan nuclear receptor NR2E3 is a key regulator of transcriptional events during photoreceptor differentiation in mammalian retina. Mutations in NR2E3 are associated with enhanced S-cone syndrome and related retinal phenotypes that reveal characteristic excess of S-cone function. This study was undertaken to determine biochemical as well as functional consequences of reported sequence variants and disease-causing mutations in NR2E3. METHODS Twenty-five different mutations in the wild-type NR2E3 expression construct were generated by site-directed mutagenesis and performed nuclear localization, gel-shift, rhodopsin promoter activity assays, and co-immunoprecipitation in cultured mammalian cells. RESULTS Of the 25 mutant proteins, 15 mislocalize at least partially to the cytoplasm. Eight of the nine changes in the DNA-binding domain (DBD) and 12 of the 14 mutations in the ligand-binding domain (LBD) of NR2E3 exhibited reduced DNA-binding and transcriptional activation of the rhodopsin promoter. Moreover, these mutations dramatically altered the interaction of NR2E3 with NRL as well as with CRX. Two NR2E3 variants between DBD and LBD showed no effect on any biochemical or functional parameter tested. CONCLUSIONS These data provide a better understanding of sequence variants, validate disease-causing mutations, and demonstrate the significance of DBD and LBD in mediating NR2E3 function. These studies contribute to molecular mechanisms underlying retinal phenotypes caused by NR2E3 mutations.
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Roduit R, Escher P, Schorderet DF. Mutations in the DNA-binding domain of NR2E3 affect in vivo dimerization and interaction with CRX. PLoS One 2009; 4:e7379. [PMID: 19823680 PMCID: PMC2757917 DOI: 10.1371/journal.pone.0007379] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 09/16/2009] [Indexed: 02/04/2023] Open
Abstract
Background NR2E3 (PNR) is an orphan nuclear receptor essential for proper photoreceptor determination and differentiation. In humans, mutations in NR2E3 have been associated with the recessively inherited enhanced short wavelength sensitive (S-) cone syndrome (ESCS) and, more recently, with autosomal dominant retinitis pigmentosa (adRP). NR2E3 acts as a suppressor of the cone generation program in late mitotic retinal progenitor cells. In adult rod photoreceptors, NR2E3 represses cone-specific gene expression and acts in concert with the transcription factors CRX and NRL to activate rod-specific genes. NR2E3 and CRX have been shown to physically interact in vitro through their respective DNA-binding domains (DBD). The DBD also contributes to homo- and heterodimerization of nuclear receptors. Methodology/Principal Findings We analyzed NR2E3 homodimerization and NR2E3/CRX complex formation in an in vivo situation by Bioluminescence Resonance Energy Transfer (BRET2). NR2E3 wild-type protein formed homodimers in transiently transfected HEK293T cells. NR2E3 homodimerization was impaired in presence of disease-causing mutations in the DBD, except for the p.R76Q and p.R104W mutant proteins. Strikingly, the adRP-linked p.G56R mutant protein interacted with CRX with a similar efficiency to that of NR2E3 wild-type and p.R311Q proteins. In contrast, all other NR2E3 DBD-mutant proteins did not interact with CRX. The p.G56R mutant protein was also more effective in abolishing the potentiation of rhodospin gene transactivation by the NR2E3 wild-type protein. In addition, the p.G56R mutant enhanced the transrepression of the M- and S-opsin promoter, while all other NR2E3 DBD-mutants did not. Conclusions/Significance These results suggest different disease mechanisms in adRP- and ESCS-patients carrying NR2E3 mutations. Titration of CRX by the p.G56R mutant protein acting as a repressor in trans may account for the severe clinical phenotype in adRP patients.
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Affiliation(s)
- Raphael Roduit
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland.
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Abstract
Although outnumbered more than 20:1 by rod photoreceptors, cone cells in the human retina mediate daylight vision and are critical for visual acuity and color discrimination. A variety of human diseases are characterized by a progressive loss of cone photoreceptors but the low abundance of cones and the absence of a macula in non-primate mammalian retinas have made it difficult to investigate cones directly. Conventional rodents (laboratory mice and rats) are nocturnal rod-dominated species with few cones in the retina, and studying other animals with cone-rich retinas presents various logistic and technical difficulties. Originating in the early 1900s, past research has begun to provide insights into cone ultrastructure but has yet to afford an overall perspective of cone cell organization. This review summarizes our past progress and focuses on the recent introduction of special mammalian models (transgenic mice and diurnal rats rich in cones) that together with new investigative techniques such as atomic force microscopy and cryo-electron tomography promise to reveal a more unified concept of cone photoreceptor organization and its role in retinal diseases.
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