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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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Shamsnajafabadi H, Kaukonen M, Bellingrath JS, MacLaren RE, Cehajic-Kapetanovic J. In Silico CRISPR-Cas-Mediated Base Editing Strategies for Early-Onset, Severe Cone-Rod Retinal Degeneration in Three Crumbs homolog 1 Patients, including the Novel Variant c.2833G>A. Genes (Basel) 2024; 15:625. [PMID: 38790254 PMCID: PMC11121323 DOI: 10.3390/genes15050625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/07/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024] Open
Abstract
Pathogenic variants in the Crumbs homolog 1 (CRB1) gene lead to severe, childhood-onset retinal degeneration leading to blindness in early adulthood. There are no approved therapies, and traditional adeno-associated viral vector-based gene therapy approaches are challenged by the existence of multiple CRB1 isoforms. Here, we describe three CRB1 variants, including a novel, previously unreported variant that led to retinal degeneration. We offer a CRISPR-Cas-mediated DNA base editing strategy as a potential future therapeutic approach. This study is a retrospective case series. Clinical and genetic assessments were performed, including deep phenotyping by retinal imaging. In silico analyses were used to predict the pathogenicity of the novel variant and to determine whether the variants are amenable to DNA base editing strategies. Case 1 was a 24-year-old male with cone-rod dystrophy and retinal thickening typical of CRB1 retinopathy. He had a relatively preserved central outer retinal structure and a best corrected visual acuity (BCVA) of 60 ETDRS letters in both eyes. Genetic testing revealed compound heterozygous variants in exon 9: c.2843G>A, p.(Cys948Tyr) and a novel variant, c.2833G>A, p.(Gly945Arg), which was predicted to likely be pathogenic by an in silico analysis. Cases 2 and 3 were two brothers, aged 20 and 24, who presented with severe cone-rod dystrophy and a significant disruption of the outer nuclear layers. The BCVA was reduced to hand movements in both eyes in Case 2 and to 42 ETDRS letters in both eyes in Case 3. Case 2 was also affected with marked cystoid macular lesions, which are common in CRB1 retinopathy, but responded well to treatment with oral acetazolamide. Genetic testing revealed two c.2234C>T, p.(Thr745Met) variants in both brothers. As G-to-A and C-to-T variants, all three variants are amenable to adenine base editors (ABEs) targeting the forward strand in the Case 1 variants and the reverse strand in Cases 2 and 3. Available PAM sites were detected for KKH-nSaCas9-ABE8e for the c.2843G>A variant, nSaCas9-ABE8e and KKH-nSaCas9-ABE8e for the c.2833G>A variant, and nSpCas9-ABE8e for the c.2234C>T variant. In this case series, we report three pathogenic CRB1 variants, including a novel c.2833G>A variant associated with early-onset cone-rod dystrophy. We highlight the severity and rapid progression of the disease and offer ABEs as a potential future therapeutic approach for this devastating blinding condition.
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Affiliation(s)
- Hoda Shamsnajafabadi
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK; (H.S.)
| | - Maria Kaukonen
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK; (H.S.)
| | - Julia-Sophia Bellingrath
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK; (H.S.)
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK; (H.S.)
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK; (H.S.)
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, John Radcliffe Hospital, Oxford OX3 9DU, UK
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Daher A, Banjak M, Noureldine J, Nehme J, El Shamieh S. Genotype-phenotype associations in CRB1 bi-allelic patients: a novel mutation, a systematic review and meta-analysis. BMC Ophthalmol 2024; 24:167. [PMID: 38622537 PMCID: PMC11017593 DOI: 10.1186/s12886-024-03419-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 03/29/2024] [Indexed: 04/17/2024] Open
Abstract
PURPOSE The goal of the study was to search for novel bi-allelic CRB1 mutations, and then to analyze the CRB1 literature at the genotypic and phenotypic levels. APPROACH We screened various variables such as the CRB1 mutation types, domains, exons, and genotypes and their relation with specific ocular phenotypes. An emphasis was given to the bi-allelic missense and nonsense mutations because of their high prevalence compared to other mutation types. Finally, we quantified the effect of various non-modifiable factors over the best-corrected visual acuity oculus uterque (BCVA OU) using multivariate linear regression models and identified genetic interactions. RESULTS A novel bi-allelic missense in the exon 9 of CRB1; c.2936G > A; p.(Gly979Asp) was found to be associated with rod-cone dystrophy (RCD). CRB1 mutation type, exons, domains, and genotype distribution varied significantly according to fundus characteristics, such as peripheral pigmentation and condition, optic disc, vessels, macular condition, and pigmentation (P < 0.05). Of the 154 articles retrieved from PubMed, 96 studies with 439 bi-allelic CRB1 patients were included. Missense mutations were significantly associated with an absence of macular pigments, pale optic disc, and periphery pigmentation, resulting in a higher risk of RCD (P < 0.05). In contrast, homozygous nonsense mutations were associated with macular pigments, periphery pigments, and a high risk of LCA (P < 0.05) and increased BCVA OU levels. We found that age, mutation types, and inherited retinal diseases were critical determinants of BCVA OU as they significantly increased it by 33% 26%, and 38%, respectively (P < 0.05). Loss of function alleles additively increased the risk of LCA, with nonsense having a more profound effect than indels. Finally, our analysis showed that p.(Cys948Tyr) and p.(Lys801Ter) and p.(Lys801Ter); p.(Cys896Ter) might interact to modify BCVA OU levels. CONCLUSION This meta-analysis updated the literature and identified genotype-phenotype associations in bi-allelic CRB1 patients.
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Affiliation(s)
- Ahmad Daher
- Medical Testing Laboratory, Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon
| | - Malak Banjak
- Rammal Hassan Rammal Research Laboratory, PhyToxE Research Group, Faculty of Sciences, Lebanese University, Nabatieh, Lebanon
| | - Jinane Noureldine
- Rammal Hassan Rammal Research Laboratory, PhyToxE Research Group, Faculty of Sciences, Lebanese University, Nabatieh, Lebanon
| | - Joseph Nehme
- Faculty of Medicine, Holy Spirit University of Kaslik (USEK), Jounieh, Lebanon
| | - Said El Shamieh
- Medical Testing Laboratory, Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon.
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Peng S, Li JJ, Song W, Li Y, Zeng L, Liang Q, Wen X, Shang H, Liu K, Peng P, Xue W, Zou B, Yang L, Liang J, Zhang Z, Guo S, Chen T, Li W, Jin M, Xing XB, Wan P, Liu C, Lin H, Wei H, Lee RWJ, Zhang F, Wei L. CRB1-associated retinal degeneration is dependent on bacterial translocation from the gut. Cell 2024; 187:1387-1401.e13. [PMID: 38412859 DOI: 10.1016/j.cell.2024.01.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 07/07/2023] [Accepted: 01/25/2024] [Indexed: 02/29/2024]
Abstract
The Crumbs homolog 1 (CRB1) gene is associated with retinal degeneration, most commonly Leber congenital amaurosis (LCA) and retinitis pigmentosa (RP). Here, we demonstrate that murine retinas bearing the Rd8 mutation of Crb1 are characterized by the presence of intralesional bacteria. While normal CRB1 expression was enriched in the apical junctional complexes of retinal pigment epithelium and colonic enterocytes, Crb1 mutations dampened its expression at both sites. Consequent impairment of the outer blood retinal barrier and colonic intestinal epithelial barrier in Rd8 mice led to the translocation of intestinal bacteria from the lower gastrointestinal (GI) tract to the retina, resulting in secondary retinal degeneration. Either the depletion of bacteria systemically or the reintroduction of normal Crb1 expression colonically rescued Rd8-mutation-associated retinal degeneration without reversing the retinal barrier breach. Our data elucidate the pathogenesis of Crb1-mutation-associated retinal degenerations and suggest that antimicrobial agents have the potential to treat this devastating blinding disease.
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Affiliation(s)
- Shanzhen Peng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Jing Jing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Wanying Song
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Ye Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Lei Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Qiaoxing Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Xiaofeng Wen
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510000, China
| | - Haitao Shang
- Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Keli Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Peiyao Peng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Wei Xue
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Bin Zou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Liu Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Juanran Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Zhihui Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Tianjin Medical University Eye Hospital, Eye Institute & School of Optometry and Ophthalmology, Tianjin 300384, China
| | - Shixin Guo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Tingting Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Wenxuan Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Department of Biostatistics, Yale School of Public Health, New Haven, CT 06510, USA
| | - Ming Jin
- Department of Ophthalmology, China-Japan Friendship Hospital, Beijing 10029, China
| | - Xiang-Bin Xing
- Department of Gastroenterology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Pengxia Wan
- Department of Ophthalmology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, China
| | - Chunqiao Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Haotian Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Hong Wei
- Precision Medicine Institute, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
| | - Richard W J Lee
- UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust, London, UK.
| | - Feng Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
| | - Lai Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China; Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou 510260, China; The First Affiliated Hospital, Department of Ophthalmology, University of South China, Hengyang 421001, Hunan, China.
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Du X, Butler AG, Chen HY. Cell-cell interaction in the pathogenesis of inherited retinal diseases. Front Cell Dev Biol 2024; 12:1332944. [PMID: 38500685 PMCID: PMC10944940 DOI: 10.3389/fcell.2024.1332944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/06/2024] [Indexed: 03/20/2024] Open
Abstract
The retina is part of the central nervous system specialized for vision. Inherited retinal diseases (IRD) are a group of clinically and genetically heterogenous disorders that lead to progressive vision impairment or blindness. Although each disorder is rare, IRD accumulatively cause blindness in up to 5.5 million individuals worldwide. Currently, the pathophysiological mechanisms of IRD are not fully understood and there are limited treatment options available. Most IRD are caused by degeneration of light-sensitive photoreceptors. Genetic mutations that abrogate the structure and/or function of photoreceptors lead to visual impairment followed by blindness caused by loss of photoreceptors. In healthy retina, photoreceptors structurally and functionally interact with retinal pigment epithelium (RPE) and Müller glia (MG) to maintain retinal homeostasis. Multiple IRD with photoreceptor degeneration as a major phenotype are caused by mutations of RPE- and/or MG-associated genes. Recent studies also reveal compromised MG and RPE caused by mutations in ubiquitously expressed ciliary genes. Therefore, photoreceptor degeneration could be a direct consequence of gene mutations and/or could be secondary to the dysfunction of their interaction partners in the retina. This review summarizes the mechanisms of photoreceptor-RPE/MG interaction in supporting retinal functions and discusses how the disruption of these processes could lead to photoreceptor degeneration, with an aim to provide a unique perspective of IRD pathogenesis and treatment paradigm. We will first describe the biology of retina and IRD and then discuss the interaction between photoreceptors and MG/RPE as well as their implications in disease pathogenesis. Finally, we will summarize the recent advances in IRD therapeutics targeting MG and/or RPE.
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Affiliation(s)
| | | | - Holly Y. Chen
- Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
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Liu S, Ren Y, Wang D, Xiao D, Li Z, Xu D, Sun Y, Wang Z, Pang J. Case report: Familial foveal retinoschisis caused by CRB1 gene mutation in a family with recessive inheritance. Front Med (Lausanne) 2023; 10:1220075. [PMID: 37636578 PMCID: PMC10451074 DOI: 10.3389/fmed.2023.1220075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/17/2023] [Indexed: 08/29/2023] Open
Abstract
X-linked retinoschisis is more common in male children and rare in females. Clinically, male patients mainly present with early onset visual impairment or vision loss, and retinal retinoschisis due to division of the inner retina. We report a long-term observation of a female patient with familial foveal retinoschisis (FFR) caused by CRB1 gene with complex heterozygotic mutation. The initial symptoms of the female patient reported in this study were very similar to some early manifestations of X-linked retinoschisis (XLRS) caused by RS1 mutations involving macular fovea. However, as time going on, the splitting height at retinal fovea of FFR gradually decreased, and the splitting extent at retinal fovea of FFR gradually decreased.
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Affiliation(s)
- Shu Liu
- Shenyang He Eye Specialist Hospital, Shenyang, China
- Liaoning Provincial Innovation Center of Ophthalmology, Shenyang, China
| | - Yue Ren
- Shenyang He Eye Specialist Hospital, Shenyang, China
| | - Di Wang
- Shenyang He Eye Specialist Hospital, Shenyang, China
| | - Dan Xiao
- Shenyang He Eye Specialist Hospital, Shenyang, China
| | - Zhuang Li
- Shenyang He Eye Specialist Hospital, Shenyang, China
| | - Dan Xu
- Shenyang Weijing Biotechnology Co., Ltd., Shenyang, China
| | - Yan Sun
- Shenyang He Eye Specialist Hospital, Shenyang, China
| | - Zhuoshi Wang
- Shenyang He Eye Specialist Hospital, Shenyang, China
| | - Jijing Pang
- Shenyang He Eye Specialist Hospital, Shenyang, China
- Shenyang Weijing Biotechnology Co., Ltd., Shenyang, China
- Institute of Innovation Research for Precision Medical Treatment, He University, Shenyang, China
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8
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Albakri A, Pisuchpen P, Capasso JE, Schneider A, Kopinsky S, Glaser T, Chiang JPW, Yomai AA, McNear D, Levin AV. Novel CRB1 pathogenic variant in Chuuk families with Leber congenital amaurosis. Am J Med Genet A 2023; 191:1007-1012. [PMID: 36595661 PMCID: PMC10262898 DOI: 10.1002/ajmg.a.63108] [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: 09/14/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 01/05/2023]
Abstract
The purpose of this article is to determine the cause of Leber congenital amaurosis (LCA) in Chuuk state, Federated States of Micronesia (FSM). In this prospective observational case series, five patients with early-onset vision loss were examined in Chuuk state, FSM, during an ocular genetics visit to study the elevated incidence of microphthalmia. Because of their low vision these patients were incorrectly assumed to have microphthalmia. A complete ophthalmological exam established a clinical diagnosis of LCA. Candidate gene exons were sequenced with a targeted retinal dystrophy panel. Five subjects in three related families were diagnosed with LCA. All five were from Tonoas Island, within the Chuuk Lagoon, with ages ranging from 6 months to 16 years. DNA sequencing of affected individuals revealed a homozygous CRB1 NM_201253.3:c.3134del pathogenic variant, which was heterozygous in their parents. CRB1 genotypes were confirmed by a PCR restriction assay. We report identification of a founder pathogenic variant in CRB1 responsible for autosomal recessive LCA in this isolated community. This discovery will lead to appropriate recurrence risk counseling.
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Affiliation(s)
- Amani Albakri
- Pediatric and Ocular Genetics, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
- Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Phattrawan Pisuchpen
- Pediatric and Ocular Genetics, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
- Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Jenina E. Capasso
- Pediatric and Ocular Genetics, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
| | - Adele Schneider
- Pediatric and Ocular Genetics, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
- Division of Genetics, Einstein Healthcare Network, Philadelphia, Pennsylvania, USA
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Sarina Kopinsky
- Division of Genetics, Einstein Healthcare Network, Philadelphia, Pennsylvania, USA
| | - Tom Glaser
- Department of Cell Biology & Human Anatomy, University of California, Davis, California, USA
| | | | | | - Donna McNear
- Independent Educational Consultant, Cambridge, Minnesota, USA
| | - Alex V. Levin
- Pediatric and Ocular Genetics, Wills Eye Hospital, Philadelphia, Pennsylvania, USA
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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9
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Daich Varela M, Georgiou M, Alswaiti Y, Kabbani J, Fujinami K, Fujinami-Yokokawa Y, Khoda S, Mahroo OA, Robson AG, Webster AR, AlTalbishi A, Michaelides M. CRB1-Associated Retinal Dystrophies: Genetics, Clinical Characteristics, and Natural History. Am J Ophthalmol 2023; 246:107-121. [PMID: 36099972 PMCID: PMC10555856 DOI: 10.1016/j.ajo.2022.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 01/24/2023]
Abstract
PURPOSE To analyze the clinical characteristics, natural history, and genetics of CRB1-associated retinal dystrophies. DESIGN Multicenter international retrospective cohort study. METHODS Review of clinical notes, ophthalmic images, and genetic testing results of 104 patients (91 probands) with disease-causing CRB1 variants. Macular optical coherence tomography (OCT) parameters, visual function, fundus characteristics, and associations between variables were the main outcome measures. RESULTS The mean age of the cohort at the first visit was 19.8 ± 16.1 (median 15) years, with a mean follow-up of 9.6 ± 10 years. Based on history, imaging, and clinical examination, 26 individuals were diagnosed with retinitis pigmentosa (RP; 25%), 54 with early-onset severe retinal dystrophy / Leber congenital amaurosis (EOSRD/LCA; 52%), and 24 with macular dystrophy (MD; 23%). Severe visual impairment was most frequent after 40 years of age for patients with RP and after 20 years of age for EOSRD/LCA. Longitudinal analysis revealed a significant difference between baseline and follow-up best-corrected visual acuity in the 3 subcohorts. Macular thickness decreased in most patients with EOSRD/LCA and MD, whereas the majority of patients with RP had increased perifoveal thickness. CONCLUSIONS A subset of individuals with CRB1 variants present with mild, adult-onset RP. EOSRD/LCA phenotype was significantly associated with null variants, and 167_169 deletion was exclusively present in the MD cohort. The poor OCT lamination may have a degenerative component, as well as being congenital. Disease symmetry and reasonable window for intervention highlight CRB1 retinal dystrophies as a promising target for trials of novel therapeutics.
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Affiliation(s)
- Malena Daich Varela
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom
| | - Michalis Georgiou
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; Jones Eye Institute (M.G.), University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Yahya Alswaiti
- St John of Jerusalem Eye Hospital group, Jerusalem, Palestine (Y.A., A.A.)
| | - Jamil Kabbani
- Imperial College London (J.K.), London, United Kingdom
| | - Kaoru Fujinami
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center (Y.F.-Y.), Tokyo, Japan
| | - Yu Fujinami-Yokokawa
- UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center (Y.F.-Y.), Tokyo, Japan; Department of Health Policy and Management, School of Medicine, Keio University(Y.F.-Y.), Tokyo, Japan
| | - Shaheeni Khoda
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom
| | - Omar A Mahroo
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom
| | - Anthony G Robson
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom
| | - Andrew R Webster
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom
| | - Alaa AlTalbishi
- St John of Jerusalem Eye Hospital group, Jerusalem, Palestine (Y.A., A.A.)
| | - Michel Michaelides
- Moorfields Eye Hospital (M.D.V., M.G., K.F., S.K., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom; UCL Institute of Ophthalmology, University College London (M.D.V., M.G., K.F., Y.F.-Y., O.A.M., A.G.R., A.R.W., M.M.), London, United Kingdom.
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10
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Kumari A, Borooah S. The Role of Microglia in Inherited Retinal Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:197-205. [PMID: 37440034 DOI: 10.1007/978-3-031-27681-1_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Inherited retinal diseases (IRDs) are a leading cause of irreversible visual loss in the developed world. The primary driver of pathology in IRDs is pathogenic genetic variant. However, there is increasing evidence, from recent studies, for a role of the immune system in disease mechanism, particularly retinal microglia. Microglia are the primary immune cells in the retina and actively contribute to disease pathogenesis when activated locally by phagocytosing photoreceptors, inducing inflammation and signaling infiltration of circulating monocytes. In this article, we discuss the evidence for the contribution of retinal microglia to IRD pathogenesis reported so far using mice model.
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Affiliation(s)
- Asha Kumari
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
| | - Shyamanga Borooah
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA.
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11
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Yamada T, Saitoh Y, Kametani K, Kamijo A, Sakamoto T, Terada N. Involvement of membrane palmitoylated protein 2 (MPP2) in the synaptic molecular complex at the mouse cerebellar glomerulus. Histochem Cell Biol 2022; 158:497-511. [PMID: 35854144 DOI: 10.1007/s00418-022-02137-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2022] [Indexed: 11/30/2022]
Abstract
We previously reported that the membrane skeletal protein 4.1G in the peripheral nervous system transports membrane palmitoylated protein 6 (MPP6), which interacts with the synaptic scaffolding protein Lin7 and cell adhesion molecule 4 (CADM4) in Schwann cells that form myelin. In the present study, we investigated the localization of and proteins related to MPP2, a highly homologous family protein of MPP6, in the cerebellum of the mouse central nervous system, in which neurons are well organized. Immunostaining for MPP2 was observed at cerebellar glomeruli (CG) in the granular layer after postnatal day 14. Using the high-resolution Airyscan mode of a confocal laser-scanning microscope, MPP2 was detected as a dot pattern and colocalized with CADM1 and Lin7, recognized as small ring/line patterns, as well as with calcium/calmodulin-dependent serine protein kinase (CASK), NMDA glutamate receptor 1 (GluN1), and M-cadherin, recognized as dot patterns, indicating the localization of MPP2 in the excitatory postsynaptic region and adherens junctions of granule cells. An immunoprecipitation analysis revealed that MPP2 formed a molecular complex with CADM1, CASK, M-cadherin, and Lin7. Furthermore, the Lin7 staining pattern showed small rings surrounding mossy fibers in wild-type CG, while it changed to the dot/spot pattern inside small rings detected with CADM1 staining in MPP2-deficient CG. These results indicate that MPP2 influences the distribution of Lin7 to synaptic cell membranes at postsynaptic regions in granule cells at CG, at which electric signals enter the cerebellum.
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Affiliation(s)
- Tomoki Yamada
- Health Science Division, Department of Medical Sciences, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Yurika Saitoh
- Health Science Division, Department of Medical Sciences, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
- Center for Medical Education, Teikyo University of Science, Adachi-ku, Tokyo, Japan
| | - Kiyokazu Kametani
- Health Science Division, Department of Medical Sciences, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
| | - Akio Kamijo
- Health Science Division, Department of Medical Sciences, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan
- Division of Basic and Clinical Medicine, Nagano College of Nursing, Komagane, Nagano, Japan
| | - Takeharu Sakamoto
- Department of Cancer Biology, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka, Japan
| | - Nobuo Terada
- Health Science Division, Department of Medical Sciences, Shinshu University Graduate School of Medicine, Science and Technology, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.
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12
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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: 0] [Impact Index Per Article: 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. Inherited eye diseases affect roughly 1:1,000 individuals worldwide. Although these diseases are often linked to variants of a single gene, it is increasingly recognized that a second variant in other genes may modify disease characteristics, including age of onset, severity, and lesion appearance. Identifying such modifier genes in humans is difficult. In this study, two modifiers of a gene associated with retinal damage leading to childhood blindness in humans (CRB1) were identified in mice. Retinal damage caused by Crb1 mutation alone was less severe than in the presence of Arhgef12 or Prkci mutations. Furthermore, the modifier gene mutations caused retinal damage only in the presence of the Crb1 mutation. Our results point to a role of mouse Crb1 and the modifying effects of Arhgef12 and Prkci in a biological network that controls adhesive interactions between cells. The variation in disease severity, lesion appearance, and visual responses in these mice provide a dramatic example of modifier gene influence. This work may lead to an improved understanding of the molecular basis of CRB1-associated retinal disease, with possible relevance to diagnostic and therapeutic intervention 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
- * E-mail: (MPK); (PMN)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail: (MPK); (PMN)
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13
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AbuMaziad AS, Abusaleh R, Bhati S. Congenital nephrotic syndrome. J Perinatol 2021; 41:2704-2712. [PMID: 34983935 DOI: 10.1038/s41372-021-01279-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 06/24/2021] [Accepted: 11/15/2021] [Indexed: 11/09/2022]
Abstract
Congenital nephrotic syndrome (CNS), a challenging form of nephrotic syndrome, is characterized by massive proteinuria, hypoalbuminemia, and edema. Extensive leakage of plasma proteins is the main feature of CNS. Patients can be diagnosed in utero or during the first few weeks of life, usually before three months. The etiology of CNS can be related to either genetic or nongenetic etiologies. Pathogenic variants in NPHS1, NPHS2, LAMB2, WT1, and PLCE1 genes have been implicated in this disease. The clinical course is complicated by significant edema, infections, thrombosis, hypothyroidism, failure to thrive, and others. Obtaining vascular access, frequent intravenous albumin infusions, diuretic use, infection prevention, and nutritional support are the mainstay management during their first month of life. The best therapy for these patients is kidney transplantation. CNS diagnosis and treatment continue to be a challenge for clinicians. This review increases the awareness about the pathogenesis, diagnosis, and management of CNS patients.
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Affiliation(s)
- Asmaa S AbuMaziad
- Department of Pediatrics, Division of Nephrology, University of Arizona, Tucson, AZ, USA.
| | - Rami Abusaleh
- Department of Pediatrics, Division of Nephrology, University of Arizona, Tucson, AZ, USA
| | - Shanti Bhati
- Department of Pediatrics, Division of Nephrology, University of Arizona, Tucson, AZ, USA
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14
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Andreazzoli M, Barravecchia I, De Cesari C, Angeloni D, Demontis GC. Inducible Pluripotent Stem Cells to Model and Treat Inherited Degenerative Diseases of the Outer Retina: 3D-Organoids Limitations and Bioengineering Solutions. Cells 2021; 10:cells10092489. [PMID: 34572137 PMCID: PMC8471616 DOI: 10.3390/cells10092489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/12/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degenerations (IRD) affecting either photoreceptors or pigment epithelial cells cause progressive visual loss and severe disability, up to complete blindness. Retinal organoids (ROs) technologies opened up the development of human inducible pluripotent stem cells (hiPSC) for disease modeling and replacement therapies. However, hiPSC-derived ROs applications to IRD presently display limited maturation and functionality, with most photoreceptors lacking well-developed outer segments (OS) and light responsiveness comparable to their adult retinal counterparts. In this review, we address for the first time the microenvironment where OS mature, i.e., the subretinal space (SRS), and discuss SRS role in photoreceptors metabolic reprogramming required for OS generation. We also address bioengineering issues to improve culture systems proficiency to promote OS maturation in hiPSC-derived ROs. This issue is crucial, as satisfying the demanding metabolic needs of photoreceptors may unleash hiPSC-derived ROs full potential for disease modeling, drug development, and replacement therapies.
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Affiliation(s)
| | - Ivana Barravecchia
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy;
- Institute of Life Sciences, Scuola Superiore Sant’Anna, 56124 Pisa, Italy;
| | | | - Debora Angeloni
- Institute of Life Sciences, Scuola Superiore Sant’Anna, 56124 Pisa, Italy;
| | - Gian Carlo Demontis
- Department of Pharmacy, University of Pisa, 56126 Pisa, Italy;
- Correspondence: (M.A.); (G.C.D.)
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15
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Roshandel D, Thompson JA, Heath Jeffery RC, Sampson DM, Chelva E, McLaren TL, Lamey TM, De Roach JN, Durkin SR, Chen FK. Multimodal Retinal Imaging and Microperimetry Reveal a Novel Phenotype and Potential Trial End Points in CRB1-Associated Retinopathies. Transl Vis Sci Technol 2021; 10:38. [PMID: 34003923 PMCID: PMC7910635 DOI: 10.1167/tvst.10.2.38] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Purpose Biallelic crumbs cell polarity complex component 1 (CRB1) mutations can present as Leber congenital amaurosis (LCA), retinitis pigmentosa (RP), or cystic maculopathy. This study reports a novel phenotype of asymptomatic fenestrated slit maculopathy (AFSM) and examines macular volume profile and microperimetry as clinical trial end points in CRB1-associated retinopathies. Methods Twelve patients from nine families with CRB1 mutation were recruited. Ultra-widefield (UWF) color fundus photography and autofluorescence (AF), spectral-domain optical coherence tomography (SD-OCT), microperimetry, and adaptive optics (AO) imaging were performed. Macular volume profiles were compared with age-matched healthy controls. Genotyping was performed using APEX genotyping microarrays, targeted next-generation sequencing, and Sanger sequencing. Results We identified one patient with LCA, five patients with RP, and four patients with macular dystrophy (MD) with biallelic CRB1 mutations. Two siblings with compound heterozygote genotype (c.[2843G>A]; [498_506del]) had AFSM characterized by localized outer retinal disruption on SD-OCT and parafoveal cone loss on AO imaging despite normal fundus appearance, visual acuity, and foveal sensitivity. UWF AF demonstrated preserved para-arteriolar retinal pigment epithelium (PPRPE) in all patients with RP. Microperimetry documented preserved central retinal function in six patients. The ratio of perifoveal-to-foveal retinal volume was greater than controls in 89% (8/9) of patients with RP or MD, whereas central subfield and total macular volume were outside normal limits in 67% (6/9). Conclusions AO imaging was helpful in detecting parafoveal cone loss in asymptomatic patients. Macular volume profile and microperimetry parameters may have utility as CRB1 trials end points. Translational Relevance Macular volume and sensitivity can be used as structural and functional end points for trials on CRB1-associated RP and MD.
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Affiliation(s)
- Danial Roshandel
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Danuta M Sampson
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia.,Surrey Biophotonics, Centre for Vision, Speech and Signal Processing and School of Biosciences and Medicine, The University of Surrey, Guildford, UK
| | - Enid Chelva
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Shane R Durkin
- Discipline of Ophthalmology and Visual Science, The University of Adelaide, South Australia, Australia.,Department of Ophthalmology, The Royal Adelaide and Queen Elizabeth Hospital, Adelaide, South Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
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16
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Functional compartmentalization of photoreceptor neurons. Pflugers Arch 2021; 473:1493-1516. [PMID: 33880652 DOI: 10.1007/s00424-021-02558-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 12/16/2022]
Abstract
Retinal photoreceptors are neurons that convert dynamically changing patterns of light into electrical signals that are processed by retinal interneurons and ultimately transmitted to vision centers in the brain. They represent the essential first step in seeing without which the remainder of the visual system is rendered moot. To support this role, the major functions of photoreceptors are segregated into three main specialized compartments-the outer segment, the inner segment, and the pre-synaptic terminal. This compartmentalization is crucial for photoreceptor function-disruption leads to devastating blinding diseases for which therapies remain elusive. In this review, we examine the current understanding of the molecular and physical mechanisms underlying photoreceptor functional compartmentalization and highlight areas where significant knowledge gaps remain.
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17
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Chytła A, Gajdzik-Nowak W, Olszewska P, Biernatowska A, Sikorski AF, Czogalla A. Not Just Another Scaffolding Protein Family: The Multifaceted MPPs. Molecules 2020; 25:molecules25214954. [PMID: 33114686 PMCID: PMC7662862 DOI: 10.3390/molecules25214954] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 01/03/2023] Open
Abstract
Membrane palmitoylated proteins (MPPs) are a subfamily of a larger group of multidomain proteins, namely, membrane-associated guanylate kinases (MAGUKs). The ubiquitous expression and multidomain structure of MPPs provide the ability to form diverse protein complexes at the cell membranes, which are involved in a wide range of cellular processes, including establishing the proper cell structure, polarity and cell adhesion. The formation of MPP-dependent complexes in various cell types seems to be based on similar principles, but involves members of different protein groups, such as 4.1-ezrin-radixin-moesin (FERM) domain-containing proteins, polarity proteins or other MAGUKs, showing their multifaceted nature. In this review, we discuss the function of the MPP family in the formation of multiple protein complexes. Notably, we depict their significant role for cell physiology, as the loss of interactions between proteins involved in the complex has a variety of negative consequences. Moreover, based on recent studies concerning the mechanism of membrane raft formation, we shed new light on a possible role played by MPPs in lateral membrane organization.
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Affiliation(s)
- Agnieszka Chytła
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Weronika Gajdzik-Nowak
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Paulina Olszewska
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Agnieszka Biernatowska
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
| | - Aleksander F. Sikorski
- Research and Development Center, Regional Specialist Hospital, Kamieńskiego 73a, 51-154 Wroclaw, Poland;
| | - Aleksander Czogalla
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, 50-383 Wroclaw, Poland; (A.C.); (W.G.-N.); (P.O.); (A.B.)
- Correspondence: ; Tel.: +48-71375-6356
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18
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Richert E, Klettner A, von der Burchard C, Roider J, Tode J. CRB1 rd8 mutation influences the age-related macular degeneration phenotype of NRF2 knockout mice and favors choroidal neovascularization. Adv Med Sci 2020; 65:71-77. [PMID: 31918066 DOI: 10.1016/j.advms.2019.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 08/08/2019] [Accepted: 11/03/2019] [Indexed: 01/23/2023]
Abstract
PURPOSE We examined the influence of retinal degeneration 8 (rd8) mutation of crumbs homolog 1 (CRB1) gene on age-related macular degeneration (AMD) phenotype in nuclear factor E2-related factor 2 knock out (NRF2-/-) mouse model. METHODS CRB1rd8 mutation genotype was determined by polymerase chain reaction from tail clips in 73 NRF2-/- mice originating from C57BL/6J background on mixed C57BL/6J and C57BL/6N ancestry. The clinical grade of AMD-like fundus alterations was determined by funduscopy, optical coherence tomography (OCT) and fluorescein angiography (FLA) at the age of 9 or 12 months. RESULTS Twelve NRF2-/- mice were wildtype CRB1+/+, 61 NRF2-/- were homozygous CRB1rd8/rd8. NRF2-/-CRB1rd8/rd8 mice had a significantly higher probability to show an advanced grade (grade 4 and 5) of AMD-like fundus alterations known to appear in NRF2-/- mice. Choroidal neovascularization (CNV) was only detected in NRF2-/-CRB1rd8/rd8 homozygous mice. CONCLUSIONS Homozygous CRB1rd8/rd8 mutation is common in commercial vendor mice strains of C57BL/6J origin if partly on C57BL/6N ancestry. The mutation has an influence on the extent of AMD-like retinal alterations in NRF2-/- mice and favors CNV formation.
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Affiliation(s)
- Elisabeth Richert
- Christian-Albrechts-University of Kiel, University Medical Center, Kiel, Germany
| | - Alexa Klettner
- Christian-Albrechts-University of Kiel, University Medical Center, Kiel, Germany
| | | | - Johann Roider
- Christian-Albrechts-University of Kiel, University Medical Center, Kiel, Germany
| | - Jan Tode
- Christian-Albrechts-University of Kiel, University Medical Center, Kiel, Germany.
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19
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Genetic and preimplantation diagnosis of cystic kidney disease with ventriculomegaly. J Hum Genet 2020; 65:455-459. [PMID: 32051522 DOI: 10.1038/s10038-020-0731-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/10/2020] [Accepted: 01/22/2020] [Indexed: 11/09/2022]
Abstract
Ventriculomegaly with cystic kidney disease (VMCKD) is a rare and severe disorder characterized by cerebral ventriculomegaly, greatly elevated maternal serum alpha-fetoprotein (MSAFP) or amniotic fluid alpha-fetoprotein (AFAFP) levels and kidney disease similar to Finnish congenital nephrosis. Recessive mutations in the CRB2 (NM_173689) gene have been shown to cause the syndrome. Here, we described a nonconsanguineous Chinese family with two fetuses affected with VMCKD. A novel compound heterozygous mutation was identified in the CRB2 gene with co-segregation. One mutation [c.1960G>C (p.A654P)] was inherited from the father, while another mutation [c.3078_c.3093delGGCGCGGCCCCGGCCC (p.L1026Lfs*110)] was inherited from the mother. Preimplantation genetic testing for monogenic disease (PGT-M) was performed for the carrier couple with full informed consent and successfully blocked the inheritance of the disease. Our study has important implications on molecular diagnosis and genetic counseling for VMCKD and extends the mutation spectrum in CRB2 gene.
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Leber congenital amaurosis: Current genetic basis, scope for genetic testing and personalized medicine. Exp Eye Res 2019; 189:107834. [PMID: 31639339 DOI: 10.1016/j.exer.2019.107834] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 10/06/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023]
Abstract
Retinal dystrophies are one of the leading causes of pediatric congenital blindness. Leber's congenital amaurosis (LCA) encompasses one of the most severe forms of inherited retinal dystrophy responsible for early-onset childhood blindness in infancy. These are clinically characterized by nystagmus, amaurotic pupil response and markedly reduced or in most instances completely absent full-field electroretinogram. LCA exhibits immense genetic heterogeneity. With advances in next-generation genetic technologies, tremendous progress has been achieved over the last two decades in discovering genes and genetic defects leading to retinal dystrophies. Currently, 28 genes have been implicated in the pathogenesis of LCA and with initial reports of success in management with targeted gene therapy the disease has attracted a lot of research attention in the recent time. The review provides an update on genetic basis of LCA, scope for genetic testing and pharmacogenetic medicine in diagnosis and treatment of these diseases.
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Cytoglobin deficiency potentiates Crb1-mediated retinal degeneration in rd8 mice. Dev Biol 2019; 458:141-152. [PMID: 31634437 DOI: 10.1016/j.ydbio.2019.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 02/02/2023]
Abstract
PURPOSE The purpose of this study is to determine the effect of Cytoglobin (Cygb) deficiency on Crb1-related retinopathy. The Crb1 cell polarity complex is required for photoreceptor function and survival. Crb1-related retinopathies encompass a broad range of phenotypes which are not completely explained by the variability of Crb1 mutations. Genes thought to modify Crb1 function are therefore important targets of research. The biological function of Cygb involves oxygen delivery, scavenging of reactive oxygen species, and nitric oxide metabolism. However, the relationship of Cygb to diseases involving the Crb1 cell polarity complex is unknown. METHODS Cygb knockout mice homozygous for the rd8 mutation (Cygb-/-rd8/rd8) were screened for ocular abnormalities and imaged using optical coherence tomography and fundus photography. Electroretinography was performed, as was histology and immunohistochemistry. Quantitative PCR was used to determine the effect of Cygb deficiency on transcription of Crb1 related cell polarity genes. RESULTS Cygb-/-rd8/rd8 mice develop an abnormal retina with severe lamination abnormalities. The retina undergoes progressive degeneration with the ventral retina more severely affected than the dorsal retina. Cygb expression is in neurons of the retinal ganglion cell layer and inner nuclear layer. Immunohistochemical studies suggest that cell death predominates in the photoreceptors. Electroretinography amplitudes show reduced a- and b-waves, consistent with photoreceptor disease. Cygb deficient retinas had only modest transcriptional perturbations of Crb1-related cell polarity genes. Cygb-/- mice without the rd8 mutation did not exhibit obvious retinal abnormalities. CONCLUSIONS Cygb is necessary for retinal lamination, maintenance of cell polarity, and photoreceptor survival in rd8 mice. These results are consistent with Cygb as a disease modifying gene in Crb1-related retinopathy. Further studies are necessary to investigate the role of Cygb in the human retina.
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Trujillo-Gonzalez I, Friday WB, Munson CA, Bachleda A, Weiss ER, Alam NM, Sha W, Zeisel SH, Surzenko N. Low availability of choline in utero disrupts development and function of the retina. FASEB J 2019; 33:9194-9209. [PMID: 31091977 PMCID: PMC6662989 DOI: 10.1096/fj.201900444r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/15/2019] [Indexed: 12/14/2022]
Abstract
Adequate supply of choline, an essential nutrient, is necessary to support proper brain development. Whether prenatal choline availability plays a role in development of the visual system is currently unknown. In this study, we addressed the role of in utero choline supply for the development and later function of the retina in a mouse model. We lowered choline availability in the maternal diet during pregnancy and assessed proliferative and differentiation properties of retinal progenitor cells (RPCs) in the developing prenatal retina, as well as visual function in adult offspring. We report that low choline availability during retinogenesis leads to persistent retinal cytoarchitectural defects, ranging from focal lesions with displacement of retinal neurons into subretinal space to severe hypocellularity and ultrastructural defects in photoreceptor organization. We further show that low choline availability impairs timely differentiation of retinal neuronal cells, such that the densities of early-born retinal ganglion cells, amacrine and horizontal cells, as well as cone photoreceptor precursors, are reduced in low choline embryonic d 17.5 retinas. Maintenance of higher proportions of RPCs that fail to exit the cell cycle underlies aberrant neuronal differentiation in low choline embryos. Increased RPC cell cycle length, and associated reduction in neurofibromin 2/Merlin protein, an upstream regulator of the Hippo signaling pathway, at least in part, explain aberrant neurogenesis in low choline retinas. Furthermore, we find that animals exposed to low choline diet in utero exhibit a significant degree of intraindividual variation in vision, characterized by marked functional discrepancy between the 2 eyes in individual animals. Together, our findings demonstrate, for the first time, that choline availability plays an essential role in the regulation of temporal progression of retinogenesis and provide evidence for the importance of adequate supply of choline for proper development of the visual system.-Trujillo-Gonzalez, I., Friday, W. B., Munson, C. A., Bachleda, A., Weiss, E. R., Alam, N. M., Sha, W., Zeisel, S. H., Surzenko, N. Low availability of choline in utero disrupts development and function of the retina.
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Affiliation(s)
- Isis Trujillo-Gonzalez
- Nutrition Research Institute, University of North Carolina–Chapel Hill, Kannapolis, North Carolina, USA
| | - Walter B. Friday
- Nutrition Research Institute, University of North Carolina–Chapel Hill, Kannapolis, North Carolina, USA
| | - Carolyn A. Munson
- Nutrition Research Institute, University of North Carolina–Chapel Hill, Kannapolis, North Carolina, USA
| | - Amelia Bachleda
- Department of Cell Biology and Physiology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, USA
| | - Ellen R. Weiss
- Department of Cell Biology and Physiology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, USA
| | - Nazia M. Alam
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, USA
- Center for Visual Restoration, Burke Neurological Institute, White Plains, New York, USA
| | - Wei Sha
- Bioinformatics Services Division, University of North Carolina–Charlotte, Kannapolis, North Carolina, USA
| | - Steven H. Zeisel
- Nutrition Research Institute, University of North Carolina–Chapel Hill, Kannapolis, North Carolina, USA
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, USA
| | - Natalia Surzenko
- Nutrition Research Institute, University of North Carolina–Chapel Hill, Kannapolis, North Carolina, USA
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina, USA
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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] [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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Kujawski S, Sonawane M, Knust E. penner/lgl2 is required for the integrity of the photoreceptor layer in the zebrafish retina. Biol Open 2019; 8:8/4/bio041830. [PMID: 31015218 PMCID: PMC6503998 DOI: 10.1242/bio.041830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The vertebrate retina is a complex tissue built from multiple neuronal cell types, which develop from a pseudostratified neuroepithelium. These cells are arranged into a highly organized and stereotypic pattern formed by nuclear and plexiform layers. The process of lamination as well as the maturation and differentiation of photoreceptor cells rely on the establishment and maintenance of apico-basal cell polarity and formation of adhesive junctions. Defects in any of these processes can result in impaired vision and are causally related to a variety of human diseases leading to blindness. While the importance of apical polarity regulators in retinal stratification and disease is well established, little is known about the function of basal regulators in retinal development. Here, we analyzed the role of Lgl2, a basolateral polarity factor, in the zebrafish retina. Lgl2 is upregulated in photoreceptor cells and in the retinal pigment epithelium by 72 h post fertilization. In both cell types, Lgl2 is localized basolaterally. Loss of zygotic Lgl2 does not interfere with retinal lamination or photoreceptor cell polarity or maturation. However, knockdown of both maternal and zygotic Lgl2 leads to impaired cell adhesion. As a consequence, severe layering defects occur in the distal retina, manifested by a breakdown of the outer plexiform layer and the outer limiting membrane. These results define zebrafish Lgl2 as an important regulator of retinal lamination, which, given the high degree of evolutionary conservation, may be preserved in other vertebrates, including human. Summary: Knockdown of penner/lgl2 leads to a breakdown of the outer plexiform layer and the outer limiting membrane in the zebrafish retina due to impaired cell adhesion.
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Affiliation(s)
- Satu Kujawski
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108 01307 Dresden, Germany
| | - Mahendra Sonawane
- Tata Institute of Fundamental Research, Department of Biological Sciences, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108 01307 Dresden, Germany
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Association of crumbs homolog-2 with mTORC1 in developing podocyte. PLoS One 2018; 13:e0202400. [PMID: 30125302 PMCID: PMC6101391 DOI: 10.1371/journal.pone.0202400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 08/02/2018] [Indexed: 02/06/2023] Open
Abstract
The evidence that gene mutations in the polarity determinant Crumbs homologs-2 (CRB2) cause congenital nephrotic syndrome suggests the functional importance of this gene product in podocyte development. Because another isoform, CRB3, was reported to repress the mechanistic/mammalian target of the rapamycin complex 1 (mTORC1) pathway, we examined the role of CRB2 function in developing podocytes in relation to mTORC1. In HEK-293 and MDCK cells constitutively expressing CRB2, we found that the protein localized to the apicolateral side of the cell plasma membrane and that this plasma membrane assembly required N-glycosylation. Confocal microscopy of the neonate mouse kidney revealed that both the tyrosine-phosphorylated form and non-phosphorylated form of CRB2 commence at the S-shaped body stage at the apicolateral side of podocyte precursor cells and move to foot processes in a capillary tuft pattern. The pattern of phosphorylated mTOR in developing podocytes was similar to that of CRB2 tyrosine phosphorylation. Additionally, the lack of a tyrosine phosphorylation site on CRB2 led to the reduced sensitivity of mTORC1 activation in response to energy starvation. CRB2 may play an important role in the mechanistic pathway of developing podocytes through tyrosine phosphorylation by associating with mTORC1 activation.
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Fu J, Nagashima M, Guo C, Raymond PA, Wei X. Novel Animal Model of Crumbs-Dependent Progressive Retinal Degeneration That Targets Specific Cone Subtypes. Invest Ophthalmol Vis Sci 2018; 59:505-518. [PMID: 29368007 PMCID: PMC5786287 DOI: 10.1167/iovs.17-22572] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Purpose Human Crb1 is implicated in some forms of retinal degeneration, suggesting a role in photoreceptor maintenance. Multiple Crumbs (Crb) polarity genes are expressed in vertebrate retina, although their functional roles are not well understood. To gain further insight into Crb and photoreceptor maintenance, we compared retinal cell densities between wild-type and Tg(RH2-2:Crb2b-sfEX/RH2-2:GFP)pt108b transgenic zebrafish, in which the extracellular domain of Crb2b-short form (Crb2b-sfEX) is expressed in the retina as a secreted protein, which disrupts the planar organization of RGB cones (red, green, and blue) by interfering with Crb2a/2b-based cone-cone adhesion. Methods We used standard morphometric techniques to assess age-related changes in retinal cell densities in adult zebrafish (3 to 27 months old), and to assess effects of the Crb2b-sfEX transgene on retinal structure and photoreceptor densities. Linear cell densities were measured in all retinal layers in radial sections with JB4-Feulgen histology. Planar (surface) densities of cones were determined in retinal flat-mounts. Cell counts from wild-type and pt108b transgenic fish were compared with both a “photoreceptor maintenance index” and statistical analysis of cell counts. Results Age-related changes in retinal cell linear densities and cone photoreceptor planar densities in wild-type adult zebrafish provided a baseline for analysis. Expression of Crb2b-sfEX caused progressive and selective degeneration of RGB cones, but had no effect on ultraviolet-sensitive (UV) cones, and increased numbers of rod photoreceptors. Conclusions These differential responses of RGB cones, UV cones, and rods to sustained exposure to Crb2b-sfEX suggest that Crb-based photoreceptor maintenance mechanisms are highly selective.
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Affiliation(s)
- Jinling Fu
- Department of Ophthalmology, the Second Hospital of Jilin University, Changchun, Jilin, China.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Mikiko Nagashima
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States
| | - Chuanyu Guo
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States
| | - Pamela A Raymond
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States
| | - Xiangyun Wei
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States.,Department of Developmental Biology, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, United States.,Department of Microbiology and Molecular Genetics, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, United States.,Louis J. Fox Center for Vision Restoration, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania, United States
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Khan KN, Robson A, Mahroo OAR, Arno G, Inglehearn CF, Armengol M, Waseem N, Holder GE, Carss KJ, Raymond LF, Webster AR, Moore AT, McKibbin M, van Genderen MM, Poulter JA, Michaelides M. A clinical and molecular characterisation of CRB1-associated maculopathy. Eur J Hum Genet 2018; 26:687-694. [PMID: 29391521 PMCID: PMC5945653 DOI: 10.1038/s41431-017-0082-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/14/2017] [Accepted: 12/05/2017] [Indexed: 12/22/2022] Open
Abstract
To date, over 150 disease-associated variants in CRB1 have been described, resulting in a range of retinal disease phenotypes including Leber congenital amaurosis and retinitis pigmentosa. Despite this, no genotype–phenotype correlations are currently recognised. We performed a retrospective review of electronic patient records to identify patients with macular dystrophy due to bi-allelic variants in CRB1. In total, seven unrelated individuals were identified. The median age at presentation was 21 years, with a median acuity of 0.55 decimalised Snellen units (IQR = 0.43). The follow-up period ranged from 0 to 19 years (median = 2.0 years), with a median final decimalised Snellen acuity of 0.65 (IQR = 0.70). Fundoscopy revealed only a subtly altered foveal reflex, which evolved into a bull’s-eye pattern of outer retinal atrophy. Optical coherence tomography identified structural changes—intraretinal cysts in the early stages of disease, and later outer retinal atrophy. Genetic testing revealed that one rare allele (c.498_506del, p.(Ile167_Gly169del)) was present in all patients, with one patient being homozygous for the variant and six being heterozygous. In trans with this, one variant recurred twice (p.(Cys896Ter)), while the four remaining alleles were each observed once (p.(Pro1381Thr), p.(Ser478ProfsTer24), p.(Cys195Phe) and p.(Arg764Cys)). These findings show that the rare CRB1 variant, c.498_506del, is strongly associated with localised retinal dysfunction. The clinical findings are much milder than those observed with bi-allelic, loss-of-function variants in CRB1, suggesting this in-frame deletion acts as a hypomorphic allele. This is the most prevalent disease-causing CRB1 variant identified in the non-Asian population to date.
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Affiliation(s)
- Kamron N Khan
- University College London Institute of Ophthalmology, University College London, London, UK. .,Inherited Eye Disease Service, Moorfields Eye Hospital, London, UK. .,Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, UK. .,Department of Ophthalmology, St. James's University Teaching Hospital, Leeds, UK.
| | - Anthony Robson
- Department of Electrophysiology, Moorfields Eye Hospital, London, UK
| | - Omar A R Mahroo
- University College London Institute of Ophthalmology, University College London, London, UK.,Inherited Eye Disease Service, Moorfields Eye Hospital, London, UK
| | - Gavin Arno
- University College London Institute of Ophthalmology, University College London, London, UK
| | - Chris F Inglehearn
- Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, UK
| | - Monica Armengol
- Inherited Eye Disease Service, Moorfields Eye Hospital, London, UK
| | - Naushin Waseem
- Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, UK
| | - Graham E Holder
- Department of Electrophysiology, Moorfields Eye Hospital, London, UK
| | - Keren J Carss
- NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK.,Department of Haematology, NHS Blood and Transplant Centre, University of Cambridge, Cambridge, CB2 0PT, UK.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Lucy F Raymond
- NIHR BioResource - Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, UK.,Department of Haematology, NHS Blood and Transplant Centre, University of Cambridge, Cambridge, CB2 0PT, UK.,Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Andrew R Webster
- University College London Institute of Ophthalmology, University College London, London, UK.,Inherited Eye Disease Service, Moorfields Eye Hospital, London, UK
| | - Anthony T Moore
- University College London Institute of Ophthalmology, University College London, London, UK.,Inherited Eye Disease Service, Moorfields Eye Hospital, London, UK.,Ophthalmology Department, University of California San Francisco Medical School, San Francisco, CA, USA
| | - Martin McKibbin
- Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, UK.,Department of Ophthalmology, St. James's University Teaching Hospital, Leeds, UK
| | - Maria M van Genderen
- Bartiméus Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands.,Department of Ophthalmology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - James A Poulter
- Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences, University of Leeds, Leeds, UK
| | - Michel Michaelides
- University College London Institute of Ophthalmology, University College London, London, UK.,Inherited Eye Disease Service, Moorfields Eye Hospital, London, UK
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Abstract
Cellular functions are often performed by multiprotein structures called protein complexes. These complexes are dynamic structures that evolve during the cell cycle or in response to external and internal stimuli, and are tightly regulated by protein expression in different tissues resulting in quantitative and qualitative variation of protein complexes. Advances in high-throughput techniques, such as mass-spectrometry and yeast two-hybrid provided a large amount of data on protein-protein interactions. This sparked the development of computational methods able to predict protein complex formation under a variety of biological and clinical conditions. However, the challenges that need to be addressed for successful computational protein complex prediction are highly complex.The post-genomic era saw an emerging number of algorithms and software, which are able to predict protein complexes from protein-protein interaction networks and a variety of other sources. Despite the high capacity of these methods to qualitatively predict protein complexes, they could provide only limited or no quantitative information of the predicted complexes. Recently, a new large-scale simulation of protein complexes was able to achieve this task by simulating protein complex formation on the proteome scale.In this chapter, we review representative methods that can predict multiple protein complexes at different scales and discuss how these can be combined with emerging sources of data in order to improve protein complex characterization.
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Nagashima M, Hadidjojo J, Barthel LK, Lubensky DK, Raymond PA. Anisotropic Müller glial scaffolding supports a multiplex lattice mosaic of photoreceptors in zebrafish retina. Neural Dev 2017; 12:20. [PMID: 29141686 PMCID: PMC5688757 DOI: 10.1186/s13064-017-0096-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/19/2017] [Indexed: 11/21/2022] Open
Abstract
Background The multiplex, lattice mosaic of cone photoreceptors in the adult fish retina is a compelling example of a highly ordered epithelial cell pattern, with single cell width rows and columns of cones and precisely defined neighbor relationships among different cone types. Cellular mechanisms patterning this multiplex mosaic are not understood. Physical models can provide new insights into fundamental mechanisms of biological patterning. In earlier work, we developed a mathematical model of photoreceptor cell packing in the zebrafish retina, which predicted that anisotropic mechanical tension in the retinal epithelium orients planar polarized adhesive interfaces to align the columns as cone photoreceptors are generated at the retinal margin during post-embryonic growth. Methods With cell-specific fluorescent reporters and in vivo imaging of the growing retinal margin in transparent juvenile zebrafish we provide the first view of how cell packing, spatial arrangement, and cell identity are coordinated to build the lattice mosaic. With targeted laser ablation we probed the tissue mechanics of the retinal epithelium. Results Within the lattice mosaic, planar polarized Crumbs adhesion proteins pack cones into a single cell width column; between columns, N-cadherin-mediated adherens junctions stabilize Müller glial apical processes. The concentration of activated pMyosin II at these punctate adherens junctions suggests that these glial bands are under tension, forming a physical barrier between cone columns and contributing to mechanical stress anisotropies in the epithelial sheet. Unexpectedly, we discovered that the appearance of such parallel bands of Müller glial apical processes precedes the packing of cones into single cell width columns, hinting at a possible role for glia in the initial organization of the lattice mosaic. Targeted laser ablation of Müller glia directly demonstrates that these glial processes support anisotropic mechanical tension in the planar dimension of the retinal epithelium. Conclusions These findings uncovered a novel structural feature of Müller glia associated with alignment of photoreceptors into a lattice mosaic in the zebrafish retina. This is the first demonstration, to our knowledge, of planar, anisotropic mechanical forces mediated by glial cells. Electronic supplementary material The online version of this article (10.1186/s13064-017-0096-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mikiko Nagashima
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI, 48109-1048, USA
| | - Jeremy Hadidjojo
- Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI, 48109-1040, USA
| | - Linda K Barthel
- Microscopy and Image Analysis Laboratory, University of Michigan, Ann Arbor, MI, USA
| | - David K Lubensky
- Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI, 48109-1040, USA.
| | - Pamela A Raymond
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI, 48109-1048, USA.
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Mechanisms of macular edema: Beyond the surface. Prog Retin Eye Res 2017; 63:20-68. [PMID: 29126927 DOI: 10.1016/j.preteyeres.2017.10.006] [Citation(s) in RCA: 342] [Impact Index Per Article: 48.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 10/24/2017] [Accepted: 10/31/2017] [Indexed: 02/07/2023]
Abstract
Macular edema consists of intra- or subretinal fluid accumulation in the macular region. It occurs during the course of numerous retinal disorders and can cause severe impairment of central vision. Major causes of macular edema include diabetes, branch and central retinal vein occlusion, choroidal neovascularization, posterior uveitis, postoperative inflammation and central serous chorioretinopathy. The healthy retina is maintained in a relatively dehydrated, transparent state compatible with optimal light transmission by multiple active and passive systems. Fluid accumulation results from an imbalance between processes governing fluid entry and exit, and is driven by Starling equation when inner or outer blood-retinal barriers are disrupted. The multiple and intricate mechanisms involved in retinal hydro-ionic homeostasis, their molecular and cellular basis, and how their deregulation lead to retinal edema, are addressed in this review. Analyzing the distribution of junction proteins and water channels in the human macula, several hypotheses are raised to explain why edema forms specifically in the macular region. "Pure" clinical phenotypes of macular edema, that result presumably from a single causative mechanism, are detailed. Finally, diabetic macular edema is investigated, as a complex multifactorial pathogenic example. This comprehensive review on the current understanding of macular edema and its mechanisms opens perspectives to identify new preventive and therapeutic strategies for this sight-threatening condition.
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31
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Hazime K, Malicki JJ. Apico-basal Polarity Determinants Encoded by crumbs Genes Affect Ciliary Shaft Protein Composition, IFT Movement Dynamics, and Cilia Length. Genetics 2017; 207:1041-1051. [PMID: 28882989 PMCID: PMC5676222 DOI: 10.1534/genetics.117.300260] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/23/2017] [Indexed: 02/04/2023] Open
Abstract
One of the most obvious manifestations of polarity in epithelia is the subdivision of the cell surface by cell junctions into apical and basolateral domains. crumbs genes are among key regulators of this form of polarity. Loss of crumbs function disrupts the apical cell junction belt and crumbs overexpression expands the apical membrane size. Crumbs proteins contain a single transmembrane domain and localize to cell junction area at the apical surface of epithelia. In some tissues, they are also found in cilia. To test their role in ciliogenesis, we investigated mutant phenotypes of zebrafish crumbs genes. In zebrafish, mutations of three crumbs genes, oko meduzy/crb2a, crb3a, and crb2b, affect cilia length in a subset of tissues. In oko meduzy (ome), this is accompanied by accumulation of other Crumbs proteins in the ciliary compartment. Moreover, intraflagellar transport (IFT) particle components accumulate in the ciliary shaft of ome;crb3a double mutants. Consistent with the above, Crb3 knockdown in mammalian cells affects the dynamics of IFT particle movement. These findings reveal crumbs-dependent mechanisms that regulate the localization of ciliary proteins, including Crumbs proteins themselves, and show that crumbs genes modulate intraflagellar transport and cilia elongation.
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Affiliation(s)
- Khodor Hazime
- Bateson Centre, Department of Biomedical Science, University of Sheffield, S10 2TN, United Kingdom
| | - Jarema J Malicki
- Bateson Centre, Department of Biomedical Science, University of Sheffield, S10 2TN, United Kingdom
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Motta FL, Salles MV, Costa KA, Filippelli-Silva R, Martin RP, Sallum JMF. The correlation between CRB1 variants and the clinical severity of Brazilian patients with different inherited retinal dystrophy phenotypes. Sci Rep 2017; 7:8654. [PMID: 28819299 PMCID: PMC5561187 DOI: 10.1038/s41598-017-09035-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/20/2017] [Indexed: 12/18/2022] Open
Abstract
Inherited retinal dystrophies are characterized by progressive retina degeneration and mutations in at least 250 genes have been associated as disease-causing. CRB1 is one of many genes analyzed in molecular diagnosis for inherited retinal dystrophy. Crumbs homolog-1 protein encoded by CRB1 is important for cell-to-cell contact, polarization of epithelial cells and the morphogenesis of photoreceptors. Pathogenic variants in CRB1 lead to a huge variety of phenotypes ranging from milder forms of inherited retinal dystrophy, such as retinitis pigmentosa to more severe phenotypes such as Leber congenital amaurosis. In this study, seven novel likely-pathogenic variants were identified: four missense variants (p.Leu479Pro, p.Ala921Pro, p.Cys948Arg and p.Asp1031Asn), two frameshift deletions (c.2536_2542del7 and c.3460_3461delTG) and one frameshift indel variant (c.276_294delinsTGAACACTGTAC). Furthermore, two patients with cone-rod dystrophy due to mutations in CRB1 were reported, supporting previous data, in which mutations in CRB1 can also cause cone-rod dystrophy. Finally, our data suggested there was a direct relation between phenotype severity and the mutation effect on protein functionality in 15 Brazilian CRB1 patients.
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Affiliation(s)
| | | | | | | | - Renan Paulo Martin
- Department of Biophysics, Federal University of Sao Paulo, Sao Paulo, Brazil
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Lajko M, Cardona HJ, Taylor JM, Farrow KN, Fawzi AA. Photoreceptor oxidative stress in hyperoxia-induced proliferative retinopathy accelerates rd8 degeneration. PLoS One 2017; 12:e0180384. [PMID: 28671996 PMCID: PMC5495396 DOI: 10.1371/journal.pone.0180384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/14/2017] [Indexed: 12/13/2022] Open
Abstract
To investigate the impact of photoreceptor oxidative stress on photoreceptor degeneration in mice carrying the rd8 mutation (C57BL/6N). We compared the hyperoxia-induced proliferative retinopathy (HIPR) model in two mouse strains (C57BL/6J and C57BL/6N). Pups were exposed to 75% oxygen, starting at birth and continuing for 14 days (P14). Mice were euthanized at P14, or allowed to recover in room air for one day (P15), seven days (P21), or 14 days (P28). We quantified retinal thickness and the length of residual photoreceptors not affected by rosette formation. In addition we explored differences in retinal immunostaining for NADPH oxidase 4 (NOX4), Rac1, vascular endothelium, and activated Mϋller cells. We analyzed photoreceptor oxidative stress using DCF staining in cross sections and quantified NOX4 protein levels using western blotting. C57BL/6N mice in HIPR showed increased oxidative stress, NOX4, and Rac1 in the photoreceptors at P14 and P15 compared to C57BL/6J. In addition, we observed significant progression of photoreceptor degeneration, with significantly accelerated rosette formation in C57BL/6N under HIPR, compared to their room air counterparts. Furthermore, C57BL/6N under HIPR had significantly thinner central retinas than C57BL/6J in HIPR. We did not find a difference in vascular disruption or Mϋller cell activation comparing the two strains in hyperoxia. In HIPR, the C57BL/6N strain carrying the rd8 mutation showed significantly accelerated photoreceptor degeneration, mediated via exacerbated photoreceptor oxidative stress, which we believe relates to Rac1-NOX dysregulation in the setting of Crb1 loss-of-function.
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Affiliation(s)
- Michelle Lajko
- Department of Ophthalmology, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America
| | - Herminio J. Cardona
- Department of Pediatrics, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America
| | - Joann M. Taylor
- Department of Pediatrics, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America
| | - Kathryn N. Farrow
- Department of Pediatrics, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America
| | - Amani A. Fawzi
- Department of Ophthalmology, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
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Ghofrani M, Yahyaei M, Brunner HG, Cremers FP, Movasat M, Imran Khan M, Keramatipour M. Homozygosity Mapping and Targeted Sanger Sequencing Identifies Three Novel CRB1 (Crumbs homologue 1) Mutations in Iranian Retinal Degeneration Families. IRANIAN BIOMEDICAL JOURNAL 2017; 21:294-302. [PMID: 28460491 PMCID: PMC5548961 DOI: 10.18869/acadpub.ibj.21.5.294] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background: Inherited retinal diseases (IRDs) are a group of genetic disorders with high degrees of clinical, genetic and allelic heterogeneity. IRDs generally show progressive retinal cell death resulting in gradual vision loss. IRDs constitute a broad spectrum of disorders including retinitis pigmentosa and Leber congenital amaurosis. In this study, we performed genotyping studies to identify the underlying mutations in three Iranian families. Methods: Having employed homozygosity mapping and Sanger sequencing, we identified the underlying mutations in the crumbs homologue 1 gene. The CRB1 protein is a part of a macromolecular complex with a vital role in retinal cell polarity, morphogenesis, and maintenance. Results: We identified a novel homozygous variant (c.1053_1061del; p.Gly352_Cys354del) in one family, a combination of a novel (c.2086T>C; p.Cys696Arg) and a known variant (c.2234C>T, p.Thr745Met) in another family and a homozygous novel variant (c.3090T>A; p.Asn1030Lys) in a third family. Conclusion: This study shows that mutations in CRB1 are relatively common in Iranian non-syndromic IRD patients.
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Affiliation(s)
- Mohammad Ghofrani
- Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mahin Yahyaei
- Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Han G. Brunner
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P.M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Morteza Movasat
- Eye Research Center, Tehran University of Medical Sciences, Farabi Eye Hospital, Tehran, Iran
| | - Muhammad Imran Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
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Rainbow Enhancers Regulate Restrictive Transcription in Teleost Green, Red, and Blue Cones. J Neurosci 2017; 37:2834-2848. [PMID: 28193687 DOI: 10.1523/jneurosci.3421-16.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/31/2016] [Accepted: 01/27/2017] [Indexed: 01/24/2023] Open
Abstract
Photoreceptor-specific transcription of individual genes collectively constitutes the transcriptional profile that orchestrates the structural and functional characteristics of each photoreceptor type. It is challenging, however, to study the transcriptional specificity of individual photoreceptor genes because each gene's distinct spatiotemporal transcription patterns are determined by the unique interactions between a specific set of transcription factors and the gene's own cis-regulatory elements (CREs), which remain unknown for most of the genes. For example, it is unknown what CREs underlie the zebrafish mpp5bponli (ponli) and crumbs2b (crb2b) apical polarity genes' restrictive transcription in the red, green, and blue (RGB) cones in the retina, but not in other retinal cell types. Here we show that the intronic enhancers of both the ponli and crb2b genes are conserved among teleost species and that they share sequence motifs that are critical for RGB cone-specific transcription. Given their similarities in sequences and functions, we name the ponli and crb2b enhancers collectively rainbow enhancers. Rainbow enhancers may represent a cis-regulatory mechanism to turn on a group of genes that are commonly and restrictively expressed in RGB cones, which largely define the beginning of the color vision pathway.SIGNIFICANCE STATEMENT Dim-light achromatic vision and bright-light color vision are initiated in rod and several types of cone photoreceptors, respectively; these photoreceptors are structurally distinct from each other. In zebrafish, although quite different from rods and UV cones, RGB cones (red, green, and blue cones) are structurally similar and unite into mirror-symmetric pentamers (G-R-B-R-G) by adhesion. This structural commonality and unity suggest that a set of genes is commonly expressed only in RGB cones but not in other cells. Here, we report that the rainbow enhancers activate RGB cone-specific transcription of the ponli and crb2b genes. This study provides a starting point to study how RGB cone-specific transcription defines RGB cones' distinct functions for color vision.
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Yang Y, Yang Y, Huang L, Zhai Y, Li J, Jiang Z, Gong B, Fang H, Kim R, Yang Z, Sundaresan P, Zhu X, Zhou Y. Whole exome sequencing identified novel CRB1 mutations in Chinese and Indian populations with autosomal recessive retinitis pigmentosa. Sci Rep 2016; 6:33681. [PMID: 27670293 PMCID: PMC5037368 DOI: 10.1038/srep33681] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/31/2016] [Indexed: 01/02/2023] Open
Abstract
Retinitis pigmentosa (RP) is a leading cause of inherited blindness characterized by progressive degeneration of the retinal photoreceptor cells. This study aims to identify genetic mutations in a Chinese family RP-2236, an Indian family RP-IC-90 and 100 sporadic Indian individuals with autosomal recessive RP (arRP). Whole exome sequencing was performed on the index patients of RP-2236, RP-IC-90 and all of the 100 sporadic Indian patients. Direct Sanger sequencing was used to validate the mutations identified. Four novel mutations and one reported mutation in the crumbs homolog 1 (CRB1) gene, which has been known to cause severe retinal dystrophies, were identified. A novel homozygous splicing mutation c.2129-1G>C was found in the three patients In family RP-2236. A homozygous point mutation p.R664C was found in RP-IC-90. A novel homozygous mutation p.G1310C was identified in patient I-44, while novel compound heterozygous mutations p.N629D and p.A593T were found in patient I-7. All mutations described above were not present in the 1000 normal controls. In conclusion, we identified four novel mutations in CRB1 in a cohort of RP patients from the Chinese and Indian populations. Our data enlarges the CRB1 mutation spectrums and may provide new target loci for RP diagnose and treatment.
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Affiliation(s)
- Yin Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China
| | - Yeming Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China.,Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Key Laboratory for NeuroInformation of Ministry of Education and Medicine Information Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Lulin Huang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Yaru Zhai
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Jie Li
- Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China
| | - Zhilin Jiang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Bo Gong
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Hao Fang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Ramasamy Kim
- Retina-vitreous services, Aravind Eye Hospital, Madurai, Tamilnadu, India
| | - Zhenglin Yang
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China.,Key Laboratory for NeuroInformation of Ministry of Education and Medicine Information Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Periasamy Sundaresan
- Department of Genetics, Aravind Medical Research Foundation, Aravind Eye Hospital, Madurai, Tamilnadu, India
| | - Xianjun Zhu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China.,Institute of Laboratory Animal Sciences, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.,Key Laboratory for NeuroInformation of Ministry of Education and Medicine Information Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Yu Zhou
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, School of Medicine, Sichuan Academy of Medical Sciences &Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.,Department of Laboratory Medicine, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China.,Key Laboratory for NeuroInformation of Ministry of Education and Medicine Information Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China.,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
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Slavotinek AM. The Family of Crumbs Genes and Human Disease. Mol Syndromol 2016; 7:274-281. [PMID: 27867342 DOI: 10.1159/000448109] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2016] [Indexed: 11/19/2022] Open
Abstract
The family of vertebrate Crumbs proteins, homologous to Drosophila Crumbs (Crb), share large extracellular domains with epidermal growth factor-like repeats and laminin-globular domains, a single transmembrane domain, and a short intracellular C-terminus containing a single membrane proximal 4.1/ezrin/radixin/moesin-binding domain and PSD-95/Discs large/ZO-1-binding motifs. There are 3 Crb genes in humans - Crumbs homolog-1 (CRB1), Crumbs homolog-2 (CRB2), and Crumbs homolog-3 (CRB3). Bilallelic loss-of-function mutations in CRB1 cause visual impairment, with Leber's congenital amaurosis and retinitis pigmentosa, whereas CRB2 mutations are associated with raised maternal serum and amniotic fluid alpha feto-protein levels, ventriculomegaly/hydrocephalus, and renal disease, ranging from focal segmental glomerulosclerosis to congenital Finnish nephrosis. CRB3 has not yet been associated with human disease. In this review, we summarize the phenotypic findings associated with deleterious sequence variants in CRB1 and CRB2. We discuss the mutational spectrum, animal models of loss of function for both genes and speculate on the likely mechanisms of disease.
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Affiliation(s)
- Anne M Slavotinek
- Department of Pediatrics, UCSF School of Medicine, University of California San Francisco, San Francisco, Calif., USA
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Markand S, Saul A, Tawfik A, Cui X, Rozen R, Smith SB. Mthfr as a modifier of the retinal phenotype of Crb1(rd8/rd8) mice. Exp Eye Res 2015; 145:164-172. [PMID: 26646559 DOI: 10.1016/j.exer.2015.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/21/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022]
Abstract
Mutations in crumb homologue 1 (CRB1) in humans are associated with Leber's congenital amaurosis (LCA) and retinitis pigmentosa (RP). There is no clear genotype-phenotype correlation for human CRB1 mutations in RP and LCA. The high variability in clinical features observed in CRB1 mutations suggests that environmental factors or genetic modifiers influence severity of CRB1 related retinopathies. Retinal degeneration 8 (rd8) is a spontaneous mutation in the Crb1 gene (Crb1(rdr/rd8)). Crb1(rdr/rd8) mice present with focal disruption in the outer retina manifesting as white spots on fundus examination. Mild retinal dysfunction with decreased b-wave amplitude has been reported in Crb1(rdr/rd8) mice at 18 months. Methylene tetrahydrofolate reductase (MTHFR) is a crucial enzyme of homocysteine metabolism. MTHFR mutations are prevalent in humans and are linked to a broad spectrum of disorders including cardiovascular and neurodegenerative diseases. We recently reported the retinal phenotype in Mthfr-deficient (Mthfr(+/-)) heterozygous mice. At 24 weeks the mice showed decreased RGC function, thinner nerve fiber layer, focal areas of vascular leakage and 20% fewer cells in the ganglion cell layer (GCL). Considering the variability in CRB1-related retinopathies and the high occurrence of human MTHFR mutations we evaluated whether Mthfr deficiency influences rd8 retinal phenotype. Mthfr heterozygous mice with rd8 mutations (Mthfr(+/-)(rd8/rd8)) and Crb(rd8/rd8) mice (Mthfr(+/+rd8/rd8)) mice were subjected to comprehensive retinal evaluation using ERG, fundoscopy, fluorescein angiography (FA), morphometric and retinal flat mount immunostaining analyses of isolectin-B4 at 8-54 wks. Assessment of retinal function revealed a significant decrease in the a-, b- and c-wave amplitudes in Mthfr(+/-)(rd8/rd8) mice at 52 wks. Fundoscopic evaluation demonstrated the presence of signature rd8 spots in Mthfr(+/+rd8/rd8) mice and an increase in the extent of these rd8 spots in Mthfr(+/-)(rd8/rd8) mice at 24 weeks and beyond. FA revealed marked vascular leakage, ischemia and vascular tortuosity in Mthfr(+/-)(rd8/rd8) mice at 24 and 52 weeks. Retinal dysplasia was observed in ∼14-33% Mthfr(+/-)(rd8/rd8) mice by morphometric analysis. This was accompanied by a ∼20% reduction in cells of the GCL of Mthfr(+/-)(rd8/rd8) mice at 24 and 52 weeks. Retinal flat mount immunostaining with isolectin-B4 showed neovascularization and loss of blood vessel integrity in Mthfr(+/-)(rd8/rd8) mice in contrast to mild vasculopathy in Mthfr(+/+rd8/rd8) mice. Taken together, our data support an earlier onset and worsened retinal phenotype when Mthfr and rd8 mutations coexist. Our study sets the stage for future studies to investigate the role of MTHFR deficiency in human CRB1 retinopathies.
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Affiliation(s)
- Shanu Markand
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; The James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
| | - Alan Saul
- The James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - Amany Tawfik
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; The James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
| | - Xuezhi Cui
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; The James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA
| | - Rima Rozen
- Departments of Pediatrics and Human Genetics, McGill University, Montreal, Canada
| | - Sylvia B Smith
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA; The James and Jean Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA; Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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Paniagua AE, Herranz-Martín S, Jimeno D, Jimeno ÁM, López-Benito S, Carlos Arévalo J, Velasco A, Aijón J, Lillo C. CRB2 completes a fully expressed Crumbs complex in the Retinal Pigment Epithelium. Sci Rep 2015; 5:14504. [PMID: 26404741 PMCID: PMC4585915 DOI: 10.1038/srep14504] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/26/2015] [Indexed: 11/24/2022] Open
Abstract
The CRB proteins CRB1, CRB2 and CRB3 are members of the cell polarity complex Crumbs in mammals that together with Scribble and Par complexes stablish the polarity of a variety of cell types. Although many members of the Crumbs complex proteins are expressed in the retinal pigment epithelium (RPE), and even though the mRNA of CRB2 has been detected in ARPE-19 cells and in the RPE/Choroid, to date no CRB protein has yet been found in this tissue. To investigate this possibility, we generated an antibody that specifically recognize the mouse CRB2 protein, and we demonstrate the expression of CRB2 in mouse RPE. Confocal analysis shows that CRB2 is restricted to the apicolateral membrane of RPE cells, and more precisely, in the tight junctions. Our study identified CRB2 as the member of the CRB protein family that is present together with the rest of the components of the Crumbs complex in the RPE apico-lateral cell membrane. Considering that the functions of CRB proteins are decisive in the establishment and maintenance of cell-cell junctions in several epithelial-derived cell types, we believe that these findings are a relevant starting point for unraveling the functions that CRB2 might perform in the RPE.
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Affiliation(s)
- Antonio E Paniagua
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - Saúl Herranz-Martín
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - David Jimeno
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - Ángela M Jimeno
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - Saray López-Benito
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - Juan Carlos Arévalo
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - Almudena Velasco
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - José Aijón
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
| | - Concepción Lillo
- Institute of Neurosciences of Castilla y León, IBSAL, Cell Biology and Pathology, University of Salamanca, 37007, Salamanca, Spain
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40
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Pan X, Schnell U, Karner CM, Small EV, Carroll TJ. A Cre-inducible fluorescent reporter for observing apical membrane dynamics. Genesis 2015; 53:285-93. [PMID: 25809849 DOI: 10.1002/dvg.22848] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 01/31/2015] [Accepted: 03/09/2015] [Indexed: 01/02/2023]
Abstract
The ability to image living tissues with fluorescent proteins has revolutionized the fields of cell and developmental biology. Fusions between fluorescent proteins and various polypeptides are allowing scientists to image tissues with sub-cellular resolution. Here, we describe the generation and activity of a genetically engineered mouse line expressing a fusion between the green fluorescent protein (GFP) and the apically localized protein Crumbs3 (Crb3). This reporter drives Cre-inducible expression of Crb3-GFP under control of the EF1a regulatory domains. The fusion protein is broadly expressed in embryonic and adult tissues and shows apical restriction in the majority of epithelial cell types. It displays a variably penetrant gain of function activity in the neural tube. However, in several cell types, over-expression of Crb3 does not appear to have any effect on normal development or maintenance. Detailed analysis of kidneys expressing this reporter indicates normal morphology and function highlighting the utility for live imaging. Thus, the EF1a(Crb3-GFP) mouse line will be of broad use for studying membrane and/or tissue dynamics in living tissues.
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Affiliation(s)
- Xinchao Pan
- Department of Internal Medicine (Nephrology), UT Southwestern Medical Center, Dallas, Texas; Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas
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Kim JY, Song JY, Karnam S, Park JY, Lee JJH, Kim S, Cho SH. Common and distinctive localization patterns of Crumbs polarity complex proteins in the mammalian eye. Gene Expr Patterns 2015; 17:31-7. [PMID: 25636444 DOI: 10.1016/j.gep.2015.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/19/2014] [Accepted: 01/21/2015] [Indexed: 12/11/2022]
Abstract
Crumbs polarity complex proteins are essential for cellular and tissue polarity, and for adhesion of epithelial cells. In epithelial tissues deletion of any of three core proteins disrupts localization of the other proteins, indicating structural and functional interdependence among core components. Despite previous studies of function and co-localization that illustrated the properties that these proteins share, it is not known whether an individual component of the complex plays a distinct role in a unique cellular and developmental context. In order to investigate this question, we primarily used confocal imaging to determine the expression and subcellular localization of the core Crumbs polarity complex proteins during ocular development. Here we show that in developing ocular tissues core Crumbs polarity complex proteins, Crb, Pals1 and Patj, generally appear in an overlapping pattern with some exceptions. All three core complex proteins localize to the apical junction of the retinal and lens epithelia. Pals1 is also localized in the Golgi of the retinal cells and Patj localizes to the nuclei of the apically located subset of progenitor cells. These findings suggest that core Crumbs polarity complex proteins exert common and independent functions depending on cellular context.
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Affiliation(s)
- Jin Young Kim
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Ji Yun Song
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Santi Karnam
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Jun Young Park
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Jamie J H Lee
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Seonhee Kim
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Seo-Hee Cho
- Shriners Hospitals Pediatric Research Center and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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Slavotinek A, Kaylor J, Pierce H, Cahr M, DeWard S, Schneidman-Duhovny D, Alsadah A, Salem F, Schmajuk G, Mehta L. CRB2 mutations produce a phenotype resembling congenital nephrosis, Finnish type, with cerebral ventriculomegaly and raised alpha-fetoprotein. Am J Hum Genet 2015; 96:162-9. [PMID: 25557780 DOI: 10.1016/j.ajhg.2014.11.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/21/2014] [Indexed: 12/17/2022] Open
Abstract
We report five fetuses and a child from three families who shared a phenotype comprising cerebral ventriculomegaly and echogenic kidneys with histopathological findings of congenital nephrosis. The presenting features were greatly elevated maternal serum alpha-fetoprotein (MSAFP) or amniotic fluid alpha-fetoprotein (AFAFP) levels or abnormalities visualized on ultrasound scan during the second trimester of pregnancy. Exome sequencing revealed deleterious sequence variants in Crumbs, Drosophila, Homolog of, 2 (CRB2) consistent with autosomal-recessive inheritance. Two fetuses with cerebral ventriculomegaly and renal microcysts were compound heterozygotes for p.Asn800Lys and p.Trp759Ter, one fetus with renal microcysts was a compound heterozygote for p.Glu643Ala and p.Asn800Lys, and one child with cerebral ventriculomegaly, periventricular heterotopias, echogenic kidneys, and renal failure was homozygous for p.Arg633Trp in CRB2. Examination of the kidneys in one fetus showed tubular cysts at the corticomedullary junction and diffuse effacement of the epithelial foot processes and microvillous transformation of the renal podocytes, findings that were similar to those reported in congenital nephrotic syndrome, Finnish type, that is caused by mutations in nephrin (NPHS1). Loss of function for crb2b and nphs1 in Danio rerio were previously shown to result in loss of the slit diaphragms of the podocytes, leading to the hypothesis that nephrosis develops from an inability to develop a functional glomerular barrier. We conclude that the phenotype associated with CRB2 mutations is pleiotropic and that the condition is an important consideration in the evaluation of high MSAFP/AFAFP where a renal cause is suspected.
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Tsang SH, Burke T, Oll M, Yzer S, Lee W, Xie YA, Allikmets R. Whole exome sequencing identifies CRB1 defect in an unusual maculopathy phenotype. Ophthalmology 2014; 121:1773-82. [PMID: 24811962 DOI: 10.1016/j.ophtha.2014.03.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 03/07/2014] [Accepted: 03/07/2014] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVE To report a new phenotype caused by mutations in the CRB1 gene in a family with 2 affected siblings. DESIGN Molecular genetics and observational case studies. PARTICIPANTS Two affected siblings and 3 unaffected family members. METHODS Each subject received a complete ophthalmic examination together with color fundus photography, fundus autofluorescence (FAF), and spectral-domain optical coherence tomography (SD-OCT). Microperimetry 1 (MP-1) mapping and electroretinogram (ERG) analysis were performed on the proband. Screening for disease-causing mutations was performed by whole exome sequencing in 3 family members followed by segregation analyses in the entire family. MAIN OUTCOME MEASURES Appearance of the macula as examined by clinical examination, fundus photography, FAF imaging, SD-OCT, and visual function by MP-1 and ERG. RESULTS The proband and her affected brother exhibited unusual, previously unreported, findings of a macular dystrophy with relative sparing of the retinal periphery beyond the vascular arcades. The FAF imaging showed severely affected areas of hypoautofluorescence that extended nasally beyond the optic disc in both eyes. A central macular patch of retinal pigment epithelium (RPE) sparing was evident in both eyes on FAF, whereas photoreceptor sparing was documented in the right eye only using SD-OCT. The affected brother presented with irregular patterns of autofluorescence in both eyes characterized by concentric rings of alternating hyper- and hypoautofluorescence, and foveal sparing of photoreceptors and RPE, as seen on SD-OCT, bilaterally. After negative results in screening for mutations in candidate genes including ABCA4 and PRPH2, DNA from 3 members of the family, including both affected siblings and their mother, was screened by whole exome sequencing resulting in identification of 2 CRB1 missense mutations, c.C3991T:p.R1331C and c.C4142T:p.P1381L, which segregated with the disease in the family. Of the 2, the p.R1331C CRB1 mutation has not been described before and the p.P1381L variant has been described in 1 patient with Leber congenital amaurosis. CONCLUSIONS This report illustrates a novel presentation of a macular dystrophy caused by CRB1 mutations. Both affected siblings exhibited a relatively well-developed retinal structure and preservation of generalized retinal function. An unusual 5-year progression of macular atrophy alone was observed that has not been described in any other CRB1-associated phenotypes.
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Affiliation(s)
- Stephen H Tsang
- Department of Ophthalmology, Columbia University, New York, New York; Department of Pathology & Cell Biology, Columbia University, New York, New York
| | - Tomas Burke
- Department of Ophthalmology, Columbia University, New York, New York; Department of Ophthalmology, Stoke Mandeville Hospital, Aylesbury, Buckinghamshire, United Kingdom
| | - Maris Oll
- Department of Ophthalmology, Columbia University, New York, New York; University Eye Clinic, Tartu University, Tartu, Estonia
| | - Suzanne Yzer
- Department of Ophthalmology, Columbia University, New York, New York; Rotterdam Eye Hospital, Rotterdam, The Netherlands
| | - Winston Lee
- Department of Ophthalmology, Columbia University, New York, New York
| | - Yajing Angela Xie
- Department of Ophthalmology, Columbia University, New York, New York
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, New York; Department of Pathology & Cell Biology, Columbia University, New York, New York.
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Abstract
Mutations in the CRB1 gene cause severe retinal degenerations, which may present as Leber congenital amaurosis, early onset retinal dystrophy, retinitis pigmentosa, or cone-rod dystrophy. Some clinical features should alert the ophthalmologist to the possibility of CRB1 disease. These features are nummular pigmentation of the retina, atrophic macula, retinal degeneration associated with Coats disease, and a unique form of retinitis pigmentosa named para-arteriolar preservation of the retinal pigment epithelium (PPRPE). Retinal degenerations associated with nanophthalmos and hyperopia, or with keratoconus, can serve as further clinical cues to mutations in CRB1. Despite this, no clear genotype-phenotype relationship has been established in CRB1 disease. In CRB1-disease, as in other inherited retinal degenerations (IRDs), it is essential to diagnose the specific disease-causing gene for the disease as genetic therapy has progressed considerably in the last few years and might be applicable.
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Affiliation(s)
- Miriam Ehrenberg
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston , Massachusetts , USA
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Pellissier LP, Lundvig DMS, Tanimoto N, Klooster J, Vos RM, Richard F, Sothilingam V, Garcia Garrido M, Le Bivic A, Seeliger MW, Wijnholds J. CRB2 acts as a modifying factor of CRB1-related retinal dystrophies in mice. Hum Mol Genet 2014; 23:3759-71. [PMID: 24565864 DOI: 10.1093/hmg/ddu089] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mutations in the CRB1 gene lead to retinal dystrophies ranging from Leber congenital amaurosis (LCA) to early-onset retinitis pigmentosa (RP), due to developmental defects or loss of adhesion between photoreceptors and Müller glia cells, respectively. Whereas over 150 mutations have been found, no clear genotype-phenotype correlation has been established. Mouse Crb1 knockout retinas show a mild phenotype limited to the inferior quadrant, whereas Crb2 knockout retinas display a severe degeneration throughout the retina mimicking the phenotype observed in RP patients associated with CRB1 mutations. Crb1Crb2 double mutant retinas have severe developmental defects similar to the phenotype observed in LCA patients associated with CRB1 mutations. Therefore, CRB2 is a candidate modifying gene of human CRB1-related retinal dystrophy. In this study, we studied the cellular localization of CRB1 and CRB2 in human retina and tested the influence of the Crb2 gene allele on Crb1-retinal dystrophies in mice. We found that in contrast to mice, in the human retina CRB1 protein was expressed at the subapical region in photoreceptors and Müller glia cells, and CRB2 only in Müller glia cells. Genetic ablation of one allele of Crb2 in heterozygote Crb1(+/-) retinas induced a mild retinal phenotype, but in homozygote Crb1 knockout mice lead to an early and severe phenotype limited to the entire inferior retina. Our data provide mechanistic insight for CRB1-related LCA and RP.
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Affiliation(s)
| | | | - Naoyuki Tanimoto
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany and
| | - Jan Klooster
- Department of Retinal Signal Processing, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam 1105 BA, The Netherlands
| | | | - Fabrice Richard
- Aix-Marseille Université, CNRS, UMR 7288, Developmental Biology Institute of Marseille (IBDM), Case 907, Marseille, Cedex 09 13288, France
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany and
| | - Marina Garcia Garrido
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany and
| | - André Le Bivic
- Aix-Marseille Université, CNRS, UMR 7288, Developmental Biology Institute of Marseille (IBDM), Case 907, Marseille, Cedex 09 13288, France
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany and
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Cordovez JA, Traboulsi EI, Capasso JE, Sadagopan KA, Ganesh A, Rychwalski PJ, Neely KA, Brodie SE, Levin AV. Retinal Dystrophy with Intraretinal Cystoid Spaces Associated with Mutations in the Crumbs Homologue (CRB1) Gene. Ophthalmic Genet 2014; 36:257-64. [DOI: 10.3109/13816810.2014.881505] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Alves CH, Pellissier LP, Wijnholds J. The CRB1 and adherens junction complex proteins in retinal development and maintenance. Prog Retin Eye Res 2014; 40:35-52. [PMID: 24508727 DOI: 10.1016/j.preteyeres.2014.01.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 01/21/2014] [Accepted: 01/27/2014] [Indexed: 12/30/2022]
Abstract
The early developing retinal neuroepithelium is composed of multipotent retinal progenitor cells that differentiate in a time specific manner, giving rise to six major types of neuronal and one type of glial cells. These cells migrate and organize in three distinct nuclear layers divided by two plexiform layers. Apical and adherens junction complexes have a crucial role in this process by the establishment of polarity and adhesion. Changes in these complexes disturb the spatiotemporal aspects of retinogenesis, leading to retinal degeneration resulting in mild or severe impairment of retinal function and vision. In this review, we summarize the mouse models for the different members of the apical and adherens junction protein complexes and describe the main features of their retinal phenotypes. The knowledge acquired from the different mutant animals for these proteins corroborate their importance in retina development and maintenance of normal retinal structure and function. More recently, several studies have tried to unravel the connection between the apical proteins, important cellular signaling pathways and their relation in retina development. Still, the mechanisms by which these proteins function remain largely unknown. Here, we hypothesize how the mammalian apical CRB1 complex might control retinogenesis and prevents onset of Leber congenital amaurosis or retinitis pigmentosa.
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Affiliation(s)
- Celso Henrique Alves
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Lucie P Pellissier
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Jan Wijnholds
- Department of Neuromedical Genetics, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands.
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Alves CH, Pellissier LP, Vos RM, Garcia Garrido M, Sothilingam V, Seide C, Beck SC, Klooster J, Furukawa T, Flannery JG, Verhaagen J, Seeliger MW, Wijnholds J. Targeted ablation of Crb2 in photoreceptor cells induces retinitis pigmentosa. Hum Mol Genet 2014; 23:3384-401. [PMID: 24493795 DOI: 10.1093/hmg/ddu048] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
In humans, the Crumbs homolog-1 (CRB1) gene is mutated in autosomal recessive Leber congenital amaurosis and early-onset retinitis pigmentosa. In mammals, the Crumbs family is composed of: CRB1, CRB2, CRB3A and CRB3B. Recently, we showed that removal of mouse Crb2 from retinal progenitor cells, and consequent removal from Müller glial and photoreceptor cells, results in severe and progressive retinal degeneration with concomitant loss of retinal function that mimics retinitis pigmentosa due to mutations in the CRB1 gene. Here, we studied the effects of cell-type-specific loss of CRB2 from the developing mouse retina using targeted conditional deletion of Crb2 in photoreceptors or Müller cells. We analyzed the consequences of targeted loss of CRB2 in the adult mouse retina using adeno-associated viral vectors encoding Cre recombinase and short hairpin RNA against Crb2. In vivo retinal imaging by means of optical coherence tomography on retinas lacking CRB2 in photoreceptors showed progressive thinning of the photoreceptor layer and cellular mislocalization. Electroretinogram recordings under scotopic conditions showed severe attenuation of the a-wave, confirming the degeneration of photoreceptors. Retinas lacking CRB2 in developing photoreceptors showed early onset of abnormal lamination, whereas retinas lacking CRB2 in developing Müller cells showed late onset retinal disorganization. Our data suggest that in the developing retina, CRB2 has redundant functions in Müller glial cells, while CRB2 has essential functions in photoreceptors. Our data suggest that short-term loss of CRB2 in adult mouse photoreceptors, but not in Müller glial cells, causes sporadic loss of adhesion between photoreceptors and Müller cells.
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Affiliation(s)
| | | | | | - Marina Garcia Garrido
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany
| | - Christina Seide
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany
| | - Susanne C Beck
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany
| | | | - Takahisa Furukawa
- Institute for Protein Research & CREST-JST, Osaka University, Osaka, Japan Department of Developmental Biology, Osaka Bioscience Institute, Suita, Osaka, Japan and
| | - John G Flannery
- Department of Molecular and Cellular Biology and The Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - Joost Verhaagen
- Department of Neuroregeneration, The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen D-72076, Germany
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Raymond PA, Colvin SM, Jabeen Z, Nagashima M, Barthel LK, Hadidjojo J, Popova L, Pejaver VR, Lubensky DK. Patterning the cone mosaic array in zebrafish retina requires specification of ultraviolet-sensitive cones. PLoS One 2014; 9:e85325. [PMID: 24465536 PMCID: PMC3897441 DOI: 10.1371/journal.pone.0085325] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 11/25/2013] [Indexed: 12/17/2022] Open
Abstract
Cone photoreceptors in teleost fish are organized in precise, crystalline arrays in the epithelial plane of the retina. In zebrafish, four distinct morphological/spectral cone types occupy specific, invariant positions within a regular lattice. The cone lattice is aligned orthogonal and parallel to circumference of the retinal hemisphere: it emerges as cones generated in a germinal zone at the retinal periphery are incorporated as single-cell columns into the cone lattice. Genetic disruption of the transcription factor Tbx2b eliminates most of the cone subtype maximally sensitive to ultraviolet (UV) wavelengths and also perturbs the long-range organization of the cone lattice. In the tbx2b mutant, the other three cone types (red, green, and blue cones) are specified in the correct proportion, differentiate normally, and acquire normal, planar polarized adhesive interactions mediated by Crumbs 2a and Crumbs 2b. Quantitative image analysis of cell adjacency revealed that the cones in the tbx2b mutant primarily have two nearest neighbors and align in single-cell-wide column fragments that are separated by rod photoreceptors. Some UV cones differentiate at the dorsal retinal margin in the tbx2b mutant, although they are severely dysmorphic and are eventually eliminated. Incorporating loss of UV cones during formation of cone columns at the margin into our previously published mathematical model of zebrafish cone mosaic formation (which uses bidirectional interactions between planar cell polarity proteins and anisotropic mechanical stresses in the plane of the retinal epithelium to generate regular columns of cones parallel to the margin) reproduces many features of the pattern disruptions seen in the tbx2b mutant.
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Affiliation(s)
- Pamela A. Raymond
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (PAR); (DKL)
| | - Steven M. Colvin
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Zahera Jabeen
- Department of Physics, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Mikiko Nagashima
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Linda K. Barthel
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jeremy Hadidjojo
- Department of Physics, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lilia Popova
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Vivek R. Pejaver
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
| | - David K. Lubensky
- Department of Physics, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (PAR); (DKL)
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50
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Lenkowski JR, Raymond PA. Müller glia: Stem cells for generation and regeneration of retinal neurons in teleost fish. Prog Retin Eye Res 2014; 40:94-123. [PMID: 24412518 DOI: 10.1016/j.preteyeres.2013.12.007] [Citation(s) in RCA: 223] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 12/28/2013] [Accepted: 12/30/2013] [Indexed: 12/31/2022]
Abstract
Adult zebrafish generate new neurons in the brain and retina throughout life. Growth-related neurogenesis allows a vigorous regenerative response to damage, and fish can regenerate retinal neurons, including photoreceptors, and restore functional vision following photic, chemical, or mechanical destruction of the retina. Müller glial cells in fish function as radial-glial-like neural stem cells. During adult growth, Müller glial nuclei undergo sporadic, asymmetric, self-renewing mitotic divisions in the inner nuclear layer to generate a rod progenitor that migrates along the radial fiber of the Müller glia into the outer nuclear layer, proliferates, and differentiates exclusively into rod photoreceptors. When retinal neurons are destroyed, Müller glia in the immediate vicinity of the damage partially and transiently dedifferentiate, re-express retinal progenitor and stem cell markers, re-enter the cell cycle, undergo interkinetic nuclear migration (characteristic of neuroepithelial cells), and divide once in an asymmetric, self-renewing division to generate a retinal progenitor. This daughter cell proliferates rapidly to form a compact neurogenic cluster surrounding the Müller glia; these multipotent retinal progenitors then migrate along the radial fiber to the appropriate lamina to replace missing retinal neurons. Some aspects of the injury-response in fish Müller glia resemble gliosis as observed in mammals, and mammalian Müller glia exhibit some neurogenic properties, indicative of a latent ability to regenerate retinal neurons. Understanding the specific properties of fish Müller glia that facilitate their robust capacity to generate retinal neurons will inform and inspire new clinical approaches for treating blindness and visual loss with regenerative medicine.
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Affiliation(s)
- Jenny R Lenkowski
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA.
| | - Pamela A Raymond
- Department of Molecular, Cellular, and Developmental Biology, College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA.
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