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Stehle IF, Imventarza JA, Woerz F, Hoffmann F, Boldt K, Beyer T, Quinn PM, Ueffing M. Human CRB1 and CRB2 form homo- and heteromeric protein complexes in the retina. Life Sci Alliance 2024; 7:e202302440. [PMID: 38570189 PMCID: PMC10992996 DOI: 10.26508/lsa.202302440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
Crumbs homolog 1 (CRB1) is one of the key genes linked to retinitis pigmentosa and Leber congenital amaurosis, which are characterized by a high clinical heterogeneity. The Crumbs family member CRB2 has a similar protein structure to CRB1, and in zebrafish, Crb2 has been shown to interact through the extracellular domain. Here, we show that CRB1 and CRB2 co-localize in the human retina and human iPSC-derived retinal organoids. In retina-specific pull-downs, CRB1 was enriched in CRB2 samples, supporting a CRB1-CRB2 interaction. Furthermore, novel interactors of the crumbs complex were identified, representing a retina-derived protein interaction network. Using co-immunoprecipitation, we further demonstrate that human canonical CRB1 interacts with CRB1 and CRB2, but not with CRB3, which lacks an extracellular domain. Next, we explored how missense mutations in the extracellular domain affect CRB1-CRB2 interactions. We observed no or a mild loss of CRB1-CRB2 interaction, when interrogating various CRB1 or CRB2 missense mutants in vitro. Taken together, our results show a stable interaction of human canonical CRB2 and CRB1 in the retina.
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Affiliation(s)
- Isabel F Stehle
- https://ror.org/03a1kwz48 Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Joel A Imventarza
- Department of Ophthalmology, Vagelos College of Physicians & Surgeons, Columbia University; New York, NY, USA
| | - Franziska Woerz
- https://ror.org/03a1kwz48 Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Felix Hoffmann
- https://ror.org/03a1kwz48 Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Karsten Boldt
- https://ror.org/03a1kwz48 Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Tina Beyer
- https://ror.org/03a1kwz48 Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Peter Mj Quinn
- Department of Ophthalmology, Vagelos College of Physicians & Surgeons, Columbia University; New York, NY, USA
| | - Marius Ueffing
- https://ror.org/03a1kwz48 Institute for Ophthalmic Research, Eberhard Karls University Tübingen, Tübingen, Germany
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Zhou X, Zhao L, Wang C, Sun W, Jia B, Li D, Fu J. Diverse functions and pathogenetic role of Crumbs in retinopathy. Cell Commun Signal 2024; 22:290. [PMID: 38802833 PMCID: PMC11129452 DOI: 10.1186/s12964-024-01673-z] [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: 02/13/2024] [Accepted: 05/20/2024] [Indexed: 05/29/2024] Open
Abstract
The Crumbs protein (CRB) family plays a crucial role in maintaining the apical-basal polarity and integrity of embryonic epithelia. The family comprises different isoforms in different animals and possesses diverse structural, localization, and functional characteristics. Mutations in the human CRB1 or CRB2 gene may lead to a broad spectrum of retinal dystrophies. Various CRB-associated experimental models have recently provided mechanistic insights into human CRB-associated retinopathies. The knowledge obtained from these models corroborates the importance of CRB in retinal development and maintenance. Therefore, complete elucidation of these models can provide excellent therapeutic prospects for human CRB-associated retinopathies. In this review, we summarize the current animal models and human-derived models of different CRB family members and describe the main characteristics of their retinal phenotypes.
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Affiliation(s)
- Xuebin Zhou
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Liangliang Zhao
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Chenguang Wang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Wei Sun
- College of Basic Medical Sciences, Jilin University, Changchun, 130000, China
| | - Bo Jia
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Dan Li
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China
| | - Jinling Fu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130000, China.
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Weatherly SM, Collin GB, Charette JR, Stone L, Damkham N, Hyde LF, Peterson JG, Hicks W, Carter GW, Naggert JK, Krebs MP, Nishina PM. Identification of Arhgef12 and Prkci as genetic modifiers of retinal dysplasia in the Crb1rd8 mouse model. PLoS Genet 2022; 18:e1009798. [PMID: 35675330 PMCID: PMC9212170 DOI: 10.1371/journal.pgen.1009798] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 06/21/2022] [Accepted: 05/03/2022] [Indexed: 12/03/2022] Open
Abstract
Mutations in the apicobasal polarity gene CRB1 lead to diverse retinal diseases, such as Leber congenital amaurosis, cone-rod dystrophy, retinitis pigmentosa (with and without Coats-like vasculopathy), foveal retinoschisis, macular dystrophy, and pigmented paravenous chorioretinal atrophy. Limited correlation between disease phenotypes and CRB1 alleles, and evidence that patients sharing the same alleles often present with different disease features, suggest that genetic modifiers contribute to clinical variation. Similarly, the retinal phenotype of mice bearing the Crb1 retinal degeneration 8 (rd8) allele varies with genetic background. Here, we initiated a sensitized chemical mutagenesis screen in B6.Cg-Crb1rd8/Pjn, a strain with a mild clinical presentation, to identify genetic modifiers that cause a more severe disease phenotype. Two models from this screen, Tvrm266 and Tvrm323, exhibited increased retinal dysplasia. Genetic mapping with high-throughput exome and candidate-gene sequencing identified causative mutations in Arhgef12 and Prkci, respectively. Epistasis analysis of both strains indicated that the increased dysplastic phenotype required homozygosity of the Crb1rd8 allele. Retinal dysplastic lesions in Tvrm266 mice were smaller and caused less photoreceptor degeneration than those in Tvrm323 mice, which developed an early, large diffuse lesion phenotype. At one month of age, Müller glia and microglia mislocalization at dysplastic lesions in both modifier strains was similar to that in B6.Cg-Crb1rd8/Pjn mice but photoreceptor cell mislocalization was more extensive. External limiting membrane disruption was comparable in Tvrm266 and B6.Cg-Crb1rd8/Pjn mice but milder in Tvrm323 mice. Immunohistological analysis of mice at postnatal day 0 indicated a normal distribution of mitotic cells in Tvrm266 and Tvrm323 mice, suggesting normal early development. Aberrant electroretinography responses were observed in both models but functional decline was significant only in Tvrm323 mice. These results identify Arhgef12 and Prkci as modifier genes that differentially shape Crb1-associated retinal disease, which may be relevant to understanding clinical variability and underlying disease mechanisms in humans.
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Affiliation(s)
| | - Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Wanda Hicks
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | | | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
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Zhang H, Shen H, Gong W, Sun X, Jiang X, Wang J, Jin L, Xu X, Luo D, Wang X. Plasma homocysteine and macular thickness in older adults-the Rugao Longevity and Aging Study. Eye (Lond) 2022; 36:1050-1060. [PMID: 33976397 PMCID: PMC9046221 DOI: 10.1038/s41433-021-01549-3] [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: 09/03/2020] [Revised: 03/08/2021] [Accepted: 04/09/2021] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES To determine the association of plasma homocysteine levels with retinal layer thickness in a large community cohort of older adults. METHODS The Rugao Longevity and Ageing Study is an observational, prospective and community-based cohort study. A total of 989 older adults who underwent spectral-domain optical coherence tomography (SD-OCT) were included and analyzed. Foveal, macular retinal nerve fibre layer (mRNFL) and ganglion cell layer plus inner plexiform layer (GC-IPL) thicknesses were measured by SD-OCT. Plasma homocysteine levels were measured using chemiluminescence immunoassay. Linear regression analyses were performed to evaluate the relationship between plasma homocysteine and retinal layer thickness while controlling for confounding factors. RESULTS Of the 989 participants, 500 (50.56%) were men. The mean age was 78.26 (4.58) years, and the mean plasma homocysteine level was 16.38 (8.05) μmol/L. In multivariable analyses, each unit increase in plasma homocysteine was associated with an 8.84 × 10-2 (95% CI: -16.54 × 10-2 to -1.15 × 10-2, p = 0.032) μm decrease in the average inner thickness of the GC-IPL after controlling for confounding factors. The association remained significant even in participants without major cardiovascular disease or diabetes (β = -10.33 × 10-2, 95% CI: -18.49 × 10-2 to -2.18 × 10-2, p = 0.013). No significant associations of plasma homocysteine levels with macular thickness or mRNFL were found in primary and sensitivity analyses (p > 0.05). CONCLUSIONS Increased plasma homocysteine levels are associated with a thinner GC-IPL. Plasma homocysteine may be a risk factor for thinner retinas in older adults.
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Affiliation(s)
- Hui Zhang
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Hangqi Shen
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Wei Gong
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Xuehui Sun
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Xiaoyan Jiang
- grid.24516.340000000123704535Key Laboratory of Arrhythmias of the Ministry of Education of China, Tongji University School of Medicine, Shanghai, China
| | - Jiucun Wang
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Li Jin
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China
| | - Xun Xu
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Dawei Luo
- grid.16821.3c0000 0004 0368 8293Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China ,Shanghai Engineering Center for Visual Science and Photomedicin, Shanghai, China ,grid.412478.c0000 0004 1760 4628Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China ,grid.412478.c0000 0004 1760 4628National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Xiaofeng Wang
- grid.8547.e0000 0001 0125 2443State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences, Fudan University, Shanghai, China ,grid.8547.e0000 0001 0125 2443Human Phenome Institute, Fudan University, Shanghai, China ,grid.413597.d0000 0004 1757 8802Shanghai Key Laboratory of Clinical Geriatric Medicine and Huadong Hospital Clinical Research Center for Geriatric Medicine, Shanghai, China ,grid.8547.e0000 0001 0125 2443National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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Shen RJ, Wang JG, Li Y, Jin ZB. Consanguinity-based analysis of exome sequencing yields likely genetic causes in patients with inherited retinal dystrophy. Orphanet J Rare Dis 2021; 16:278. [PMID: 34130719 PMCID: PMC8204521 DOI: 10.1186/s13023-021-01902-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/07/2021] [Indexed: 12/11/2022] Open
Abstract
Background Consanguineous families have a relatively high prevalence of genetic disorders caused by bi-allelic mutations in recessive genes. This study aims to evaluate the effectiveness and efficiency of a consanguinity-based exome sequencing approach to capturing genetic mutations in inherited retinal dystrophy families with consanguineous marriages. Methods Ten unrelated consanguineous families with a proband affected by inherited retinal dystrophy were recruited in this study. All participants underwent comprehensive ophthalmic examinations. Whole exome sequencing was performed, followed by a homozygote-prior strategy to rapidly filter disease-causing mutations. Bioinformatic prediction of pathogenicity, Sanger sequencing and co-segregation analysis were carried out for further validation. Results In ten consanguineous families, a total of 10 homozygous mutations in 8 IRD genes were identified, including 2 novel mutations, c.1654_1655delAG (p. R552Afs*5) in gene FAM161A in a patient diagnosed with retinitis pigmentosa, and c.830T > C (p.L277P) in gene CEP78 in a patient diagnosed with cone and rod dystrophy. Conclusion The genetic etiology in consanguineous families with IRD were successfully identified using consanguinity-based analysis of exome sequencing data, suggesting that this approach could provide complementary insights into genetic diagnoses in consanguineous families with variant genetic disorders. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-01902-5.
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Affiliation(s)
- Ren-Juan Shen
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Jun-Gang Wang
- Department of Ophthalmology, Eye Hospital of Shandong First Medical University, State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Yang Li
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China.
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Talib M, Boon CJF. Retinal Dystrophies and the Road to Treatment: Clinical Requirements and Considerations. Asia Pac J Ophthalmol (Phila) 2020; 9:159-179. [PMID: 32511120 PMCID: PMC7299224 DOI: 10.1097/apo.0000000000000290] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022] Open
Abstract
: Retinal dystrophies (RDs) comprise relatively rare but devastating causes of progressive vision loss. They represent a spectrum of diseases with marked genetic and clinical heterogeneity. Mutations in the same gene may lead to different diagnoses, for example, retinitis pigmentosa or cone dystrophy. Conversely, mutations in different genes may lead to the same phenotype. The age at symptom onset, and the rate and characteristics of peripheral and central vision decline, may vary widely per disease group and even within families. For most RD cases, no effective treatment is currently available. However, preclinical studies and phase I/II/III gene therapy trials are ongoing for several RD subtypes, and recently the first retinal gene therapy has been approved by the US Food and Drug Administration for RPE65-associated RDs: voretigene neparvovec-rzyl (Luxturna). With the rapid advances in gene therapy studies, insight into the phenotypic spectrum and long-term disease course is crucial information for several RD types. The vast clinical heterogeneity presents another important challenge in the evaluation of potential efficacy in future treatment trials, and in establishing treatment candidacy criteria. This perspective describes these challenges, providing detailed clinical descriptions of several forms of RD that are caused by genes of interest for ongoing and future gene or cell-based therapy trials. Several ongoing and future treatment options will be described.
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Affiliation(s)
- Mays Talib
- Department of Ophthalmology, Leiden, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden, The Netherlands
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, University of Amsterdam. Amsterdam, The Netherlands
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ERG Alteration Due to the rd8 Mutation of the Crb1 Gene in Cln3 +/+ rd8-/rd8- Mice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020. [PMID: 31884644 DOI: 10.1007/978-3-030-27378-1_65] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Mattapallil et al. described that vendor lines for C57BL/6 N mice may carry the rd8 mutation that leads to an ocular phenotype, which could be mistaken for an induced retinal degeneration. This mouse strain is widely used in ophthalmic research as a background for modeling retinal degeneration. In the process of studying Cln3Δex7/8 knock-in mice on a C57BL/6 N background, we became aware of this issue. The aim of this study thus was to use electroretinography to investigate the age-dependent functional loss in Cln3+/+ rd8-/rd8- mice and compare it to C57BL/6 J mice.The scotopic and photopic amplitudes of the a-wave and b-wave decrease significantly in mutant mice with increasing age, and the implicit time is prolonged. Especially the oscillatory potentials arising from inner retinal interaction seem to be notably affected by the rd8 mutation. Surprisingly, the amplitudes in young C57BL/6 J mice were lower than those measured in C57BL/6 N at any time point.Our results indicate that the rd8 mutation present in C57BL/6 N mice affects the function of the inner and outer retina. This is surprising given that the major retinal morphological alterations due to the rd8 mutation are found in the outer retina.We conclude that the rd8 mutation does affect the retinal function in Cln3+/+ rd8-/rd8- mice in a variable manner. Epigenetic factors and modifying genes lead to a phenotype shift in these mice. Interpreting the results of previous studies in mutant mice on C57BL/6 N background is challenging as comparing results obtained in independent studies or on other mouse backgrounds may be misleading. Using littermates as controls remains the only valid option.
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8
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Cho SH, Nahar A, Kim JH, Lee M, Kozmik Z, Kim S. Targeted deletion of Crb1/Crb2 in the optic vesicle models key features of leber congenital amaurosis 8. Dev Biol 2019; 453:141-154. [PMID: 31145883 DOI: 10.1016/j.ydbio.2019.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/20/2019] [Accepted: 05/21/2019] [Indexed: 01/01/2023]
Abstract
The Crb1 and 2 (Crumbs homolog 1 & 2) genes encode large, single-pass transmembrane proteins essential for the apicobasal polarity and adhesion of epithelial cells. Crb1 mutations cause degenerative retinal diseases in humans, including Leber congenital amaurosis type 8 (LCA8) and retinitis pigmentosa type 12 (RP12). In LCA8, impaired photoreceptor development and/or survival is thought to cause blindness during early infancy, whereas, in RP12, progressive photoreceptor degeneration damages peripheral vision later in life. There are multiple animal models of RP12 pathology, but no experimental model of LCA8 recapitulates the full spectrum of its pathological features. To generate a mouse model of LCA8 and identify the functions of Crb1/2 in developing ocular tissues, we used an mRx-Cre driver to generate allelic combinations that enabled conditional gene ablation from the optic vesicle stage. In this series only Crb1/2 double knockout (dKO) mice exhibited characteristics of human LCA8 disease: locally thickened retina with spots devoid of cells, aberrant positioning of retinal cells, severely disrupted lamination, and depigmented retinal-pigmented epithelium. Retinal defects antedated E12.5, which is far earlier than the stage at which photoreceptor cells mainly differentiate. Most remarkably, Crb1/Crb2 dKO showed a severely attenuated electroretinogram at the eye opening stage. These results suggest that human LCA8 can be modeled in the mouse by simultaneously ablating Crb1/2 from the beginning of eye development. Importantly, they also indicate that LCA8 is caused by malfunction of retinal progenitor cells during early ocular development rather than by defective photoreceptor-Muller glial interaction, a mechanism proposed for RP12.
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Affiliation(s)
- Seo-Hee Cho
- Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA.
| | - Ankur Nahar
- Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Ji Hyang Kim
- Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Matthew Lee
- Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Zbynek Kozmik
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Seonhee Kim
- Shriners Hospitals Pediatric Research Center, Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
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9
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Navneet S, Zhao J, Wang J, Mysona B, Barwick S, Ammal Kaidery N, Saul A, Kaddour-Djebbar I, Bollag WB, Thomas B, Bollinger KE, Smith SB. Hyperhomocysteinemia-induced death of retinal ganglion cells: The role of Müller glial cells and NRF2. Redox Biol 2019; 24:101199. [PMID: 31026769 PMCID: PMC6482349 DOI: 10.1016/j.redox.2019.101199] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/05/2019] [Accepted: 04/10/2019] [Indexed: 12/23/2022] Open
Abstract
Hyperhomocysteinemia (Hhcy), or increased levels of the excitatory amino acid homocysteine (Hcy), is implicated in glaucoma, a disease characterized by increased oxidative stress and loss of retinal ganglion cells (RGCs). Whether Hhcy is causative or merely a biomarker for RGC loss in glaucoma is unknown. Here we analyzed the role of NRF2, a master regulator of the antioxidant response, in Hhcy-induced RGC death in vivo and in vitro. By crossing Nrf2−/− mice and two mouse models of chronic Hhcy (Cbs+/- and Mthfr+/- mice), we generated Cbs+/-Nrf2−/− and Mthfr+/-Nrf2−/− mice and performed systematic analysis of retinal architecture and visual acuity followed by assessment of retinal morphometry and gliosis. We observed significant reduction of inner retinal layer thickness and reduced visual acuity in Hhcy mice lacking NRF2. These functional deficits were accompanied by fewer RGCs and increased gliosis. Given the key role of Müller glial cells in maintaining RGCs, we established an ex-vivo indirect co-culture system using primary RGCs and Müller cells. Hhcy-exposure decreased RGC viability, which was abrogated when cells were indirectly cultured with wildtype (WT) Müller cells, but not with Nrf2−/− Müller cells. Exposure of WT Müller cells to Hhcy yielded a robust mitochondrial and glycolytic response, which was not observed in Nrf2−/− Müller cells. Taken together, the in vivo and in vitro data suggest that deleterious effects of Hhcy on RGCs are likely dependent upon the health of retinal glial cells and the availability of an intact retinal antioxidant response mechanism. Oxidative stress is linked to homocysteine (Hcy)-induced retinal ganglion cell death. NRF2's role in protecting ganglion cells from excess Hcy was studied in vitro/vivo. Hyper-Hcy mice were crossed with Nrf2−/− mice to study retinal function/structure. Ganglion cells co-cultured with primary WT Müller glial cells survived Hcy treatment. Nrf2−/− Müller cells did not afford neuroprotective advantage to Hcy-treated cells.
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Affiliation(s)
- Soumya Navneet
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Jing Zhao
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Jing Wang
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Barbara Mysona
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Shannon Barwick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA
| | - Navneet Ammal Kaidery
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA
| | - Alan Saul
- James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Ismail Kaddour-Djebbar
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, One Freedom Way, Augusta, GA, 30904, USA
| | - Wendy B Bollag
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA; Charlie Norwood VA Medical Center, One Freedom Way, Augusta, GA, 30904, USA
| | - Bobby Thomas
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA; Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA; Department of Drug Discovery, Medical University of South Carolina, Charleston, SC, USA
| | - Kathryn E Bollinger
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; James and Jean Culver Vision Discovery Institute, Augusta University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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Detailed electroretinographic findings in rd8 mice. Doc Ophthalmol 2017; 134:195-203. [DOI: 10.1007/s10633-017-9585-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/23/2017] [Indexed: 11/25/2022]
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Forman OP, Hitti RJ, Boursnell M, Miyadera K, Sargan D, Mellersh C. Canine genome assembly correction facilitates identification of a MAP9 deletion as a potential age of onset modifier for RPGRIP1-associated canine retinal degeneration. Mamm Genome 2016; 27:237-45. [PMID: 27017229 DOI: 10.1007/s00335-016-9627-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/15/2016] [Indexed: 11/25/2022]
Abstract
Retinal degeneration (RD) in the Miniature Long Haired Dachshund (MLHD) is a cone-rod dystrophy resulting in eventual blindness in affected individuals. In a previous study, a 44-nucleotide insertion (ins44) in exon 2 of RPGRIP1 was associated with RD. However, results on an extended population of MLHD revealed a variable RD onset age for ins44 homozygous dogs. Further investigations using a genome-wide association study comparing early onset and late onset RD cases identified an age of onset modifying locus for RD, approximately 30 Mb upstream of RPGRIP1 on chr15. In this investigation, target enriched sequencing identified a MAP9 deletion spanning approximately 22 kb associated with early RD onset. Identification of the deletion required correction to the CanFam3.1 genome build as canine MAP9 is part of a historic tandem duplication, resulting in incomplete assembly of this genome region. The deletion breakpoints were identified in MAP9 intron 10 and in a downstream partial MAP9 pseudogene. The fusion of these two genes, which we have called MAP9 EORD (microtubule-associated protein, early onset retinal degeneration), is in frame and is expressed at the RNA level, with the 3' region containing several predicted deleterious variants. We speculate that MAP9 associates with α-tubulin in the basal body of the cilium. RPGRIP1 is also known to locate to the cilium, where it is closely associated with RPGR. RPGRIP1 mutations also cause redistribution of α-tubulin away from the ciliary region in photoreceptors. Hence, a MAP9 partial deficit is a particularly attractive candidate to synergise with a partial RPGRIP1 deficit to cause a more serious disease.
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Affiliation(s)
- Oliver P Forman
- Kennel Club Genetics Centre, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - Rebekkah J Hitti
- Kennel Club Genetics Centre, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK.
| | - Mike Boursnell
- Kennel Club Genetics Centre, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - Keiko Miyadera
- School of Veterinary Medicine, University of Pennsylvania, 3900 Delancey St, Philadelphia, PA, 19104, USA
| | - David Sargan
- Comparative Genetics Group, Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Rd., Cambridge, CB3 0ES, UK
| | - Cathryn Mellersh
- Kennel Club Genetics Centre, Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
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