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Gong Y, Ke Y, Yu Z, Pan J, Zhou X, Jiang Y, Zhou M, Zeng H, Geng X, Hu G. Identified RP2 as a prognostic biomarker for glioma, facilitating glioma pathogenesis mainly via regulating tumor immunity. Aging (Albany NY) 2023; 15:8155-8184. [PMID: 37602882 PMCID: PMC10497014 DOI: 10.18632/aging.204962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023]
Abstract
Glioma is the most common primary intracranial tumor in the central nervous system, with a high degree of malignancy and poor prognosis, easy to recur, difficult to cure. The mutation of Retinitis Pigmentosa 2 (RP2) can cause retinitis pigmentosa, it is a prognostic factor of osteosarcoma, however, its role in glioma remains unclear. Based on the data from TCGA and GTEx, we identified RP2 as the most related gene for glioma by WGCNA, and used a series of bioinformatics analyses including LinkedOmics, GSCA, CTD, and so on, to explore the expression of RP2 in glioma and the biological functions it is involved in. The results showed that RP2 was highly expressed in glioma, and its overexpression could lead to poor prognosis. In addition, the results of enrichment analysis showed that RP2 was highly correlated with cell proliferation and immune response. And then, we found significant enrichment of Macrophages among immune cells. Furthermore, our experiments have confirmed that Macrophages can promote the development of glioma by secreting or influencing the secretion of some cytokines. Moreover, we investigated the influence of RP2 on the immunotherapy of glioma and the role of m6A modification in the influence of RP2 on glioma. Ultimately, we determined that RP2 is an independent prognostic factor that is mainly closely related to immune for glioma.
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Affiliation(s)
- Yiyang Gong
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Yun Ke
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Zichuan Yu
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Jingying Pan
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Xuanrui Zhou
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Yike Jiang
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Minqin Zhou
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Hong Zeng
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Xitong Geng
- Second College of Clinical Medicine, Nanchang University, Nanchang, Jiangxi 330047, China
| | - Guowen Hu
- Department of Neurosurgery, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
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Georgiou M, Robson AG, Jovanovic K, Guimarães TACD, Ali N, Pontikos N, Uwaydat SH, Mahroo OA, Cheetham ME, Webster AR, Hardcastle AJ, Michaelides M. RP2-Associated X-linked Retinopathy: Clinical Findings, Molecular Genetics, and Natural History. Ophthalmology 2023; 130:413-422. [PMID: 36423731 PMCID: PMC10567581 DOI: 10.1016/j.ophtha.2022.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To review and describe in detail the clinical course, functional and anatomic characteristics of RP2-associated retinal degeneration. DESIGN Retrospective case series. PARTICIPANTS Male participants with disease-causing variants in the RP2 gene. METHODS Review of all case notes and results of molecular genetic testing, retinal imaging (fundus autofluorescence [FAF] imaging, OCT), and electrophysiology assessment. MAIN OUTCOME MEASURES Molecular genetic testing, clinical findings including best-corrected visual acuity (BCVA), qualitative and quantitative retinal imaging analysis, and electrophysiology parameters. RESULTS Fifty-four molecularly confirmed patients were identified from 38 pedigrees. Twenty-eight disease-causing variants were identified, with 20 not previously clinically characterized. Fifty-three patients (98.1%) presented with retinitis pigmentosa. The mean age of onset (range ± standard deviation [SD]) was 9.6 years (1-57 ± 9.2 years). Forty-four patients (91.7%) had childhood-onset disease, with mean age of onset of 7.6 years. The most common first symptom was night blindness (68.8%). Mean BCVA (range ± SD) was 0.91 logarithm of the minimum angle of resolution (logMAR) (0-2.7 ± 0.80) and 0.94 logMAR (0-2.7 ± 0.78) for right and left eyes, respectively. On the basis of the World Health Organization visual impairment criteria, 18 patients (34%) had low vision. The majority (17/22) showed electroretinogram (ERG) evidence of a rod-cone dystrophy. Pattern ERG P50 was undetectable in all but 2 patients. A range of FAF findings was observed, from normal to advanced atrophy. There were no statistically significant differences between right and left eyes for ellipsoid zone width (EZW) and outer nuclear layer (ONL) thickness. The mean annual rate of EZW loss was 219 μm/year, and the mean annual decrease in ONL thickness was 4.93 μm/year. No patient with childhood-onset disease had an identifiable ellipsoid zone (EZ) after the age of 26 years at baseline or follow-up. Four patients had adulthood-onset disease and a less severe phenotype. CONCLUSIONS This study details the clinical phenotype of RP2 retinopathy in a large cohort. The majority presented with early-onset severe retinal degeneration, with early macular involvement and complete loss of the foveal photoreceptor layer by the third decade of life. Full-field ERGs revealed rod-cone dystrophy in the vast majority, but with generalized (peripheral) cone system involvement of widely varying severity in the first 2 decades of life. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.
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Affiliation(s)
- Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Katarina Jovanovic
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Thales A C de Guimarães
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Naser Ali
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Nikolas Pontikos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Sami H Uwaydat
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Michael E Cheetham
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Alison J Hardcastle
- 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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Kuruvilla SE, Song E, Raoof N, van Bysterveldt K, Oliver VF, Hong SC, Al-Taie R, Wilson G, Vincent AL. Genotypic and phenotypic characterisation of RP2- and RPGR-associated X-linked inherited retinal dystrophy, including female manifestations. Clin Exp Ophthalmol 2023. [PMID: 36882936 DOI: 10.1111/ceo.14220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/24/2023] [Accepted: 02/28/2023] [Indexed: 03/09/2023]
Abstract
BACKGROUND With the promise of gene replacement therapy, eligible males and females with X-linked inherited retinal dystrophy (XL-IRD) should be identified. METHODS Retrospective observational cohort study to establish the phenotypic and genotypic spectrum of XL-IRD within New Zealand (NZ). Thirty-two probands, including 9 females, with molecularly proven XL-IRD due to RP2 or RPGR mutations, and 72 family members, of which 43 were affected, were identified from the NZ IRD Database. Comprehensive ophthalmic phenotyping, familial cosegregation, genotyping, and bioinformatics were undertaken. Main outcome measures were: RP2 and RPGR pathogenic variant spectrum, phenotype in males and females (symptoms, age of onset, visual acuity, refraction, electrophysiology, autofluorescence, retinal appearance), and genotype-phenotype correlation. RESULTS For 32 families, 26 unique pathogenic variants were identified; in RP2 (n = 6, 21.9% of all families), RPGR exons 1-14 (n = 10, 43.75%), and RPGR-ORF15 (n = 10, 34.3%). Three RP2 and 8 RPGR exons 1-14 variants are novel, rare, and cosegregate. Thirty-one percent of carrier females were significantly affected, with 18.5% of families initially classified as autosomal dominant. Of five Polynesian families, 80% had novel disease-causing variants. One Māori family showed keratoconus segregating with an ORF15 variant. CONCLUSIONS Significant disease was present in 31% of genetically proven female carriers, often leading to an erroneous presumption of the inheritance pattern. Pathogenic variants in 44% of the families were in exon 1-14 of RPGR, more frequent than usually described, which may inform the gene testing algorithm. Proving cosegregation in families for novel variants and identifying affected females and males translates to optimised clinical care and potential for gene therapy.
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Affiliation(s)
- Shilpa E Kuruvilla
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Eileen Song
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Naz Raoof
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Katherine van Bysterveldt
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Verity F Oliver
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Sheng Chiong Hong
- Eye Department - Gisborne Hospital, Hauora Tairawhiti, Gisborne, New Zealand
| | - Rasha Al-Taie
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, Manukau Super Clinic, Counties Manukau District Health Board, Manukau, New Zealand
| | - Graham Wilson
- Eye Department - Gisborne Hospital, Hauora Tairawhiti, Gisborne, New Zealand
| | - Andrea L Vincent
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
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Travis AM, Pearring JN. Human Mutations in Arl3, a Small GTPase Involved in Lipidated Cargo Delivery to the Cilia, Cause Retinal Dystrophy. Adv Exp Med Biol 2023; 1415:283-288. [PMID: 37440046 DOI: 10.1007/978-3-031-27681-1_41] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Photoreceptors are highly polarized sensory neurons. Precise localization of signaling molecules within the ciliary outer segment is critical for photoreceptor function and viability. The small GTPase Arl3 plays a particularly important role in photoreceptors as it regulates outer segment enrichment of lipidated proteins essential for the visual response: transducin-α, transducin-γ, PDEα, PDE β, and Grk1. Recently, mutations in Arl3 have been identified in human patients with nonsyndromic autosomal recessive and dominant inherited retinal degenerations as well as syndromic Joubert syndrome including retinal dystrophy.
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Affiliation(s)
- Amanda M Travis
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA
| | - Jillian N Pearring
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI, USA.
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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5
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Travis AM, Manocha S, Willer JR, Wessler TS, Skiba NP, Pearring JN. Disrupting the ciliary gradient of active Arl3 affects rod photoreceptor nuclear migration. eLife 2023; 12:80533. [PMID: 36598133 PMCID: PMC9831603 DOI: 10.7554/elife.80533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 01/03/2023] [Indexed: 01/05/2023] Open
Abstract
The small GTPase Arl3 is important for the enrichment of lipidated proteins to primary cilia, including the outer segment of photoreceptors. Human mutations in the small GTPase Arl3 cause both autosomal recessive and dominant inherited retinal dystrophies. We discovered that dominant mutations result in increased active G-protein-Arl3-D67V has constitutive activity and Arl3-Y90C is fast cycling-and their expression in mouse rods resulted in a displaced nuclear phenotype due to an aberrant Arl3-GTP gradient. Using multiple strategies, we go on to show that removing or restoring the Arl3-GTP gradient within the cilium is sufficient to rescue the nuclear migration defect. Together, our results reveal that an Arl3 ciliary gradient is involved in proper positioning of photoreceptor nuclei during retinal development.
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Affiliation(s)
- Amanda M Travis
- Department of Ophthalmology and Visual Science, University of Michigan-Ann ArborAnn ArborUnited States
| | - Samiya Manocha
- Department of Ophthalmology and Visual Science, University of Michigan-Ann ArborAnn ArborUnited States
| | - Jason R Willer
- Department of Ophthalmology and Visual Science, University of Michigan-Ann ArborAnn ArborUnited States
| | - Timothy S Wessler
- Department of Mathematics, University of North Carolina at Chapel HillChapel HillUnited States
| | - Nikolai P Skiba
- Department of Ophthalmology, Duke UniversityDurhamUnited States
| | - Jillian N Pearring
- Department of Ophthalmology and Visual Science, University of Michigan-Ann ArborAnn ArborUnited States,Department of Cell and Developmental Biology, University of Michigan–Ann ArborAnn ArborUnited States
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Cheloni R, Jackson D, Moosajee M. A Natural History Study of RP2-Related Retinopathy. J Clin Med 2022; 11:jcm11236877. [PMID: 36498452 PMCID: PMC9738434 DOI: 10.3390/jcm11236877] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/10/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
X-linked retinitis pigmentosa (RP) is a severe form of RP, often with early macular involvement. This study aimed to characterise the natural history of patients with a diagnosis of X-linked RP due to RP2 mutations. Clinical details, best-corrected visual acuity (BCVA) and multimodal retinal imaging were retrospectively collected from patients with RP2 variants from Moorfields Eye Hospital (London, UK). Measures of the ellipsoid-zone (EZ) width, central retinal thickness (CRT), and thickness of the photoreceptor and retinal pigment epithelium complex (PR+RPE, taken between the external limiting membrane and RPE) were extracted from spectral-domain optical coherence tomography (SD-OCT) scans. A total of 47 affected males (median baseline age: 20 years, IQR: 12.5−36.5) were included, and 41 had two or more visits (median follow-up: 8.0 years, IQR: 3.2−14.5). A total of 24 RP2 variants were identified, 13 of which were novel. BCVA dropped from 0.66 LogMAR at baseline (IQR, 0.35−1.4) to 1.3 LogMAR at the most recent visit (IQR: 0.6−1.4). SD-OCT revealed a prevalent outer retinal atrophy (n = 23/35, 65.7%), and measurable EZ width at baseline in 34.3% of patients (n = 12). Age significantly affected all quantitative measures (p < 0.001) except EZ width (p = 0.58), with exponential decays of 46−49% and 12.6−33.9% per decade for BCVA and SD-OCT measures, respectively. RP2 patients exhibited rapid progression to outer retina atrophy and early macular involvement with substantial vision loss by age 30−40.
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Affiliation(s)
- Riccardo Cheloni
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Daniel Jackson
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- The Francis Crick Institute, London NW1 1AT, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- Correspondence:
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7
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Fu L, Li Y, Yao S, Guo Q, You Y, Zhu X, Lei B. Autosomal Recessive Rod-Cone Dystrophy Associated With Compound Heterozygous Variants in ARL3 Gene. Front Cell Dev Biol 2021; 9:635424. [PMID: 33748123 PMCID: PMC7969994 DOI: 10.3389/fcell.2021.635424] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/15/2021] [Indexed: 01/17/2023] Open
Abstract
Purpose: ARL3 (ADP-ribosylation factor-like 3) variants cause autosomal dominant retinitis pigmentosa (RP) or autosomal recessive Joubert syndrome. We found a family with rod-cone dystrophy (RCD) and verified it was associated with compound heterozygous variants in ARL3 gene. Methods: Ophthalmic examinations including optical coherence tomography and electroretinogram (ERG) were performed. Targeted next generation sequencing (NGS) was performed for the proband using a custom designed panel. Sanger sequencing and co-segregation were conducted in the family members. Changes of protein structure mediated by the variants were studied in vitro. ARL3 protein stability and its interaction with RP2 protein were assessed by cycloheximide chase assay and co-immunoprecipitation (Co-IP) assay. Results: Visual acuity of the 18-year-old male proband was 0.25 in the right and 0.20 in the left eye, while his non-consanguineous parents and sister was normal. The proband showed signs of RCD, including nyctalopia, peripheral field loss, bone-spicule deposits in the retina, and reduced ERG responses. The father, aged 50 years old, showed visual acuity of 1.0 in both eyes. Unlike the proband, he presented late onset and mild cone-rod dystrophy (CRD), including macular atrophy, central scotomata, moderate reduction in photopic ERG responses. None of all the family members had hearing abnormality, mental dysplasia or gait instability. We identified two novel compound heterozygous variants (c.91A>G, p.T31A; c.353G>T, p.C118F) in ARL3 in the proband, while his father only had variant c.91A>G. Bioinformatics analysis indicated amino acid positions of the two variants are highly conserved among species. The in silico tools predicted the variants to be harmful. Protein structure analysis showed the two variants had potential to alter the protein structure. Based on the ACMG guidelines, the two variants were likely pathogenic. In addition, the ARL3 mutations destabilized ARL3 protein, and the mutation c.353G>T disrupted the interaction between ARL3 and RP2 in HEK293T cells. Conclusions: We showed novel compound heterozygous variants in ARL3 were associated with early onset of autosomal recessive RCD, while c.91A>G along may be associated with a late onset of dominant CRD. The two variants in ARL3 could be causative by destabilizing ARL3 protein and impairing its interaction with RP2 protein.
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Affiliation(s)
- Leming Fu
- Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ya Li
- Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute/Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Shun Yao
- Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute/Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Qingge Guo
- Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute/Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ya You
- Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute/Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Xianjun Zhu
- Department of Laboratory Medicine, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Lei
- Henan University People's Hospital, Henan Provincial People's Hospital, Zhengzhou, China
- Henan Branch of National Clinical Research Center for Ocular Diseases, Henan Eye Institute/Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
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8
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Santos-Rebouças CB, Boy R, Vianna EQ, Gonçalves AP, Piergiorge RM, Abdala BB, Dos Santos JM, Calassara V, Machado FB, Medina-Acosta E, Pimentel MMG. Skewed X-Chromosome Inactivation and Compensatory Upregulation of Escape Genes Precludes Major Clinical Symptoms in a Female With a Large Xq Deletion. Front Genet 2020; 11:101. [PMID: 32194616 PMCID: PMC7064548 DOI: 10.3389/fgene.2020.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/29/2020] [Indexed: 11/13/2022] Open
Abstract
In mammalian females, X-chromosome inactivation (XCI) acts as a dosage compensation mechanism that equalizes X-linked genes expression between homo- and heterogametic sexes. However, approximately 12–23% of X-linked genes escape from XCI, being bi-allelic expressed. Herein, we report on genetic and functional data from an asymptomatic female of a Fragile X syndrome family, who harbors a large deletion on the X-chromosome. Array-CGH uncovered that the de novo, terminal, paternally originated 32 Mb deletion on Xq25-q28 spans 598 RefSeq genes, including escape and variable escape genes. Androgen receptor (AR) and retinitis pigmentosa 2 (RP2) methylation assays showed extreme skewed XCI ratios from both peripheral blood and buccal mucosa, silencing the abnormal X-chromosome. Surprisingly, transcriptome-wide analysis revealed that escape and variable escape genes spanning the deletion are mostly upregulated on the active X-chromosome, precluding major clinical/cognitive phenotypes in the female. Metaphase high count, hemizygosity concordance for microsatellite markers, and monoallelic expression of genes within the deletion suggest the absence of mosaicism in both blood and buccal mucosa. Taken together, our data suggest that an additional protective gene-by-gene mechanism occurs at the transcriptional level in the active X-chromosome to counterbalance detrimental phenotype effects of large Xq deletions.
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Affiliation(s)
- Cíntia B Santos-Rebouças
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Raquel Boy
- Pedro Ernesto University Hospital, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Evelyn Q Vianna
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Andressa P Gonçalves
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Rafael M Piergiorge
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bianca B Abdala
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jussara M Dos Santos
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Veluma Calassara
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Filipe B Machado
- Department of Biological Sciences, Minas Gerais State University, Ubá, Brazil
| | - Enrique Medina-Acosta
- Laboratory of Biotechnology, State University of Northern Rio de Janeiro Darcy Ribeiro, Rio de Janeiro, Brazil
| | - Márcia M G Pimentel
- Department of Genetics, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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9
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Abstract
UNC119 and PDEδ are lipid-binding proteins and are thought to form diffusible complexes with transducin-α and prenylated OS proteins, respectively, to mediate their trafficking to photoreceptor outer segments. Here, we investigate mechanisms of trafficking which are controlled by Arf-like protein 3 (Arl3), a small GTPase. The activity of ARL3 is regulated by a GEF (ARL13b) and a GAP (RP2). In a mouse germline knockout of RP2, ARL3-GTP is abundant as its intrinsic GTPase activity is extremely low. High levels of ARL3-GTP impair binding and trafficking of cargo to the outer segment. Germline knockout of ARL3 is embryonically lethal generating a syndromic ciliopathy-like phenotype. Retina- and rod-specific knockout of ARL3 allow to determine the precise mechanisms leading to photoreceptor degeneration. The knockouts reveal binary functions of ARL3-GTP as a key molecule in late-stage photoreceptor ciliogenesis and cargo displacement factor.
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Affiliation(s)
- Christin Hanke-Gogokhia
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA. .,Department of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
| | - Jeanne M Frederick
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Houbin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA. .,Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA. .,Department of Biology, University of Utah, Salt Lake City, UT, USA.
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10
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Zhang J, Gao F, Du C, Wang J, Pi X, Guo W, Li J, Li H, Ma Y, Zhang W, Mu H, Hu Y, Cui X. A novel RP2 missense mutation Q158P identified in an X-linked retinitis pigmentosa family impaired RP2 protein stability. Gene 2019; 707:86-92. [PMID: 31071385 DOI: 10.1016/j.gene.2019.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/19/2019] [Accepted: 05/03/2019] [Indexed: 12/23/2022]
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal degenerative diseases. X-linked RP accounts for nearly 15% of all RP cases. In this study, we identified a novel RP2 missense mutation Q158P in a Chinese XLRP family. The RP2 Q158P mutation located in the RP2 TBCC domain and obviously destabilized RP2 protein in ARPE-19 cells. The proteasome inhibitor MG132 could restore the RP2 Q158P protein levels. Meanwhile, lower doses of bortezomib and carfilzomib, another two proteasome inhibitors that have been approved in multiple myeloma clinical therapy, also could rescue the RP2 Q158P protein levels. The ubiquitination of RP2 Q158P protein obviously increased when compared with wild type RP2 protein. Our findings broadened the spectrum of RP2 mutations and may contribute a better understanding of the molecular mechanism of XLRP.
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Kurata K, Hosono K, Hayashi T, Mizobuchi K, Katagiri S, Miyamichi D, Nishina S, Sato M, Azuma N, Nakano T, Hotta Y. X-linked Retinitis Pigmentosa in Japan: Clinical and Genetic Findings in Male Patients and Female Carriers. Int J Mol Sci 2019; 20:E1518. [PMID: 30917587 DOI: 10.3390/ijms20061518] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 03/23/2019] [Accepted: 03/25/2019] [Indexed: 12/18/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is a type of severe retinal dystrophy, and female carriers of XLRP demonstrate markedly variable clinical severity. In this study, we aimed to elucidate the clinical findings of male patients with and female carriers of XLRP in a Japanese cohort and demonstrate the genetic contribution. Twelve unrelated families (13 male patients, 15 female carriers) harboring pathogenic mutations in RPGR or RP2 were included, and comprehensive ophthalmic examinations were performed. To identify potential pathogenic mutations, targeted next-generation sequencing was employed. Consequently, we identified 11 pathogenic mutations, of which five were novel. Six and five mutations were detected in RPGR and RP2, respectively. Only one mutation was detected in ORF15. Affected male patients with RP2 mutations tended to have lower visual function than those with RPGR mutations. Female carriers demonstrated varying visual acuities and visual fields. Among the female carriers, 92% had electroretinographical abnormalities and 63% had a radial autofluorescent pattern, and the carriers who had higher myopia showed worse visual acuity and more severe retinal degeneration. Our results expand the knowledge of the clinical phenotypes of male patients with and female carriers of XLRP and suggest the possibility that RP2 mutations are relatively highly prevalent in Japan.
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12
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Fu YC, Chen N, Qiu ZL, Liu L, Shen J. Compound pathogenic mutation in the USH2A gene in Chinese RP families detected by whole‑exome sequencing. Mol Med Rep 2018; 18:5016-5022. [PMID: 30280194 PMCID: PMC6236299 DOI: 10.3892/mmr.2018.9530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 09/04/2018] [Indexed: 12/19/2022] Open
Abstract
Retinitis pigmentosa (RP) is a common form of inherited retinal degeneration that causes progressive loss of vision or adult blindness, characterized by the impairment of rod and cone photoreceptors. At present, mutations in >60 pathogenic genes have been confirmed to cause RP. The predominant modes of inheritance are autosomal dominant, autosomal recessive and X‑linked. In addition, other modes of inheritance, including digenic or mitochondrial inheritance, have been reported. In previous decades, with the development of sequencing techniques, significant advances in identifying novel RP pathogenic genes and screening mutations have been made. In the present study, whole‑exome sequencing was performed on samples from two Chinese pedigrees diagnosed with RP. A compound heterozygous mutation in the gene usherin 2A (USH2A; c.6,485+5G>A/c.11,156G>A) and a heterozygous X‑linked mutation in the gene retinitis pigmentosa 2 (RP2) ARL3 GTPase‑activating protein (RP2; c.358C>T) were identified by Sanger sequencing and co‑segregation analysis, of which the pathogenic mutation (c.6,485+5G>A) in USH2A has not been previously reported among Chinese patients. The findings of the present study may expand on current knowledge of RP among the Chinese population, providing essential assistance in the molecular diagnosis and screening of RP, and promoting further investigation of the pathogenesis of RP.
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Affiliation(s)
- Yue-Chuan Fu
- Department of Ophthalmology, The Shanghai Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200120, P.R. China
| | - Na Chen
- Department of Ophthalmology, The Shanghai Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200120, P.R. China
| | - Zi-Long Qiu
- Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Lin Liu
- Department of Ophthalmology, The Shanghai Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200120, P.R. China
| | - Jie Shen
- Department of Ophthalmology, The Shanghai Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200120, P.R. China
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Lyraki R, Lokaj M, Soares DC, Little A, Vermeren M, Marsh JA, Wittinghofer A, Hurd T. Characterization of a novel RP2-OSTF1 interaction and its implication for actin remodelling. J Cell Sci 2018; 131:jcs.211748. [PMID: 29361551 DOI: 10.1242/jcs.211748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/21/2017] [Indexed: 11/20/2022] Open
Abstract
Retinitis pigmentosa 2 (RP2) is the causative gene for a form of X-linked retinal degeneration. RP2 was previously shown to have GTPase-activating protein (GAP) activity towards the small GTPase ARL3 via its N-terminus, but the function of the C-terminus remains elusive. Here, we report a novel interaction between RP2 and osteoclast-stimulating factor 1 (OSTF1), an intracellular protein that indirectly enhances osteoclast formation and activity and is a negative regulator of cell motility. Moreover, this interaction is abolished by a human pathogenic mutation in RP2. We utilized a structure-based approach to pinpoint the binding interface to a strictly conserved cluster of residues on the surface of RP2 that spans both the C- and N-terminal domains of the protein, and which is structurally distinct from the ARL3-binding site. In addition, we show that RP2 is a positive regulator of cell motility in vitro, recruiting OSTF1 to the cell membrane and preventing its interaction with the migration regulator Myo1E.
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Affiliation(s)
- Rodanthi Lyraki
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Mandy Lokaj
- Structural Biology Group, Max-Planck Institut für Molekulare Physiologie, Abteilung Strukturelle Biologie, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Dinesh C Soares
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Abigail Little
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Matthieu Vermeren
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK.,MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Joseph A Marsh
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Alfred Wittinghofer
- Structural Biology Group, Max-Planck Institut für Molekulare Physiologie, Abteilung Strukturelle Biologie, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Toby Hurd
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
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Lyraki R, Megaw R, Hurd T. Disease mechanisms of X-linked retinitis pigmentosa due to RP2 and RPGR mutations. Biochem Soc Trans 2016; 44:1235-44. [PMID: 27911705 DOI: 10.1042/BST20160148] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 01/24/2023]
Abstract
Photoreceptor degeneration is the prominent characteristic of retinitis pigmentosa (RP), a heterogeneous group of inherited retinal dystrophies resulting in blindness. Although abnormalities in many pathways can cause photoreceptor degeneration, one of the most important causes is defective protein transport through the connecting cilium, the structure that connects the biosynthetic inner segment with the photosensitive outer segment of the photoreceptors. The majority of patients with X-linked RP have mutations in the retinitis pigmentosa GTPase regulator (RPGR) or RP2 genes, the protein products of which are both components of the connecting cilium and associated with distinct mechanisms of protein delivery to the outer segment. RP2 and RPGR proteins are associated with severe diseases ranging from classic RP to atypical forms. In this short review, we will summarise current knowledge generated by experimental studies and knockout animal models, compare and discuss the prominent hypotheses about the two proteins' functions in retinal cell biology.
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15
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Boisselier É, Demers É, Cantin L, Salesse C. How to gather useful and valuable information from protein binding measurements using Langmuir lipid monolayers. Adv Colloid Interface Sci 2017; 243:60-76. [PMID: 28372794 DOI: 10.1016/j.cis.2017.03.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 12/22/2022]
Abstract
This review presents data on the influence of various experimental parameters on the binding of proteins onto Langmuir lipid monolayers. The users of the Langmuir methodology are often unaware of the importance of choosing appropriate experimental conditions to validate the data acquired with this method. The protein Retinitis pigmentosa 2 (RP2) has been used throughout this review to illustrate the influence of these experimental parameters on the data gathered with Langmuir monolayers. The methods detailed in this review include the determination of protein binding parameters from the measurement of adsorption isotherms, infrared spectra of the protein in solution and in monolayers, ellipsometric isotherms and fluorescence micrographs.
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Affiliation(s)
- Élodie Boisselier
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
| | - Éric Demers
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Line Cantin
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Christian Salesse
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
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Liu F, Qin Y, Yu S, Soares DC, Yang L, Weng J, Li C, Gao M, Lu Z, Hu X, Liu X, Jiang T, Liu JY, Shu X, Tang Z, Liu M. Pathogenic mutations in retinitis pigmentosa 2 predominantly result in loss of RP2 protein stability in humans and zebrafish. J Biol Chem 2017; 292:6225-6239. [PMID: 28209709 DOI: 10.1074/jbc.m116.760314] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 02/14/2017] [Indexed: 12/20/2022] Open
Abstract
Mutations in retinitis pigmentosa 2 (RP2) account for 10-20% of X-linked retinitis pigmentosa (RP) cases. The encoded RP2 protein is implicated in ciliary trafficking of myristoylated and prenylated proteins in photoreceptor cells. To date >70 mutations in RP2 have been identified. How these mutations disrupt the function of RP2 is not fully understood. Here we report a novel in-frame 12-bp deletion (c.357_368del, p.Pro120_Gly123del) in zebrafish rp2 The mutant zebrafish shows reduced rod phototransduction proteins and progressive retinal degeneration. Interestingly, the protein level of mutant Rp2 is almost undetectable, whereas its mRNA level is near normal, indicating a possible post-translational effect of the mutation. Consistent with this hypothesis, the equivalent 12-bp deletion in human RP2 markedly impairs RP2 protein stability and reduces its protein level. Furthermore, we found that a majority of the RP2 pathogenic mutations (including missense, single-residue deletion, and C-terminal truncation mutations) severely destabilize the RP2 protein. The destabilized RP2 mutant proteins are degraded via the proteasome pathway, resulting in dramatically decreased protein levels. The remaining non-destabilizing mutations T87I, R118H/R118G/R118L/R118C, E138G, and R211H/R211L are suggested to impair the interaction between RP2 and its protein partners (such as ARL3) or with as yet unknown partners. By utilizing a combination of in silico, in vitro, and in vivo approaches, our work comprehensively indicates that loss of RP2 protein structural stability is the predominating pathogenic consequence for most RP2 mutations. Our study also reveals a role of the C-terminal domain of RP2 in maintaining the overall protein stability.
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Affiliation(s)
- Fei Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Yayun Qin
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Shanshan Yu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Dinesh C Soares
- MRC Human Genetics Unit/Centre for Genomic and Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom, and
| | - Lifang Yang
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jun Weng
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Chang Li
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Meng Gao
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Zhaojing Lu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xuebin Hu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xiliang Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Tao Jiang
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Jing Yu Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xinhua Shu
- Department of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, United Kingdom
| | - Zhaohui Tang
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Mugen Liu
- From the Key Laboratory of Molecular Biophysics of Ministry of Education, Department of Genetics and Developmental Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China,
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17
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Zhang H, Hanke-Gogokhia C, Jiang L, Li X, Wang P, Gerstner CD, Frederick JM, Yang Z, Baehr W. Mistrafficking of prenylated proteins causes retinitis pigmentosa 2. FASEB J 2014; 29:932-42. [PMID: 25422369 DOI: 10.1096/fj.14-257915] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The retinitis pigmentosa 2 polypeptide (RP2) functions as a GTPase-activating protein (GAP) for ARL3 (Arf-like protein 3), a small GTPase. ARL3 is an effector of phosphodiesterase 6 Δ (PDE6D), a prenyl-binding protein and chaperone of prenylated protein in photoreceptors. Mutations in the human RP2 gene cause X-linked retinitis pigmentosa (XLRP) and cone-rod dystrophy (XL-CORD). To study mechanisms causing XLRP, we generated an RP2 knockout mouse. The Rp2h(-/-) mice exhibited a slowly progressing rod-cone dystrophy simulating the human disease. Rp2h(-/-) scotopic a-wave and photopic b-wave amplitudes declined at 1 mo of age and continued to decline over the next 6 mo. Prenylated PDE6 subunits and G-protein coupled receptor kinase 1 (GRK1) were unable to traffic effectively to the Rp2h(-/-) outer segments. Mechanistically, absence of RP2 GAP activity increases ARL3-GTP levels, forcing PDE6D to assume a predominantly "closed" conformation that impedes binding of lipids. Lack of interaction disrupts trafficking of PDE6 and GRK1 to their destination, the photoreceptor outer segments. We propose that hyperactivity of ARL3-GTP in RP2 knockout mice and human patients with RP2 null alleles leads to XLRP resembling recessive rod-cone dystrophy.
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Affiliation(s)
- Houbin Zhang
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Christin Hanke-Gogokhia
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Li Jiang
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Xiaobo Li
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Pu Wang
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Cecilia D Gerstner
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Jeanne M Frederick
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Zhenglin Yang
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Wolfgang Baehr
- *The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Institute of Laboratory Medicine, Hospital of University of Electronic Science and Technology of China and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China; School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China; Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA; Department of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, Germany; and Department of Biology, University of Utah, Salt Lake City, Utah, USA
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