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Ballios BG, Mandola A, Tayyib A, Tumber A, Garkaby J, Vong L, Heon E, Roifman CM, Vincent A. Deep phenotypic characterization of the retinal dystrophy in patients with RNU4ATAC-associated Roifman syndrome. Eye (Lond) 2023; 37:3734-3742. [PMID: 37225827 PMCID: PMC10697969 DOI: 10.1038/s41433-023-02581-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/01/2023] [Accepted: 05/11/2023] [Indexed: 05/26/2023] Open
Abstract
PURPOSE To characterize the retinal phenotype in RNU4ATAC-associated Roifman syndrome. METHODS Ten patients (including 8 males) with molecularly confirmed Roifman syndrome underwent detailed ophthalmologic evaluation including fundus imaging, fundus autofluorescence (FAF) imaging, spectral-domain optical coherence tomography (SD-OCT), and electroretinography (ERG). Six patients had follow-up eye exams. All patients also underwent comprehensive examination for features of extra-retinal Roifman syndrome. RESULTS All patients had biallelic RNU4ATAC variants. Nyctalopia was common (7/10). Visual acuity at presentation ranged from 20/20 to 20/200 (Age Range: 5-41 years). Retinal exam revealed features of generalized retinopathy with mid-peripheral pigment epithelial changes. A para or peri-foveal ring of hyper-autofluorescence was the commonest FAF abnormality noted (6/8). The SD-OCT demonstrated relative preservation of the foveal ellipsoid zone in six cases; associated features included cystoid changes (5/10) and posterior staphyloma (3/10). The ERG was abnormal in all patients; nine showed generalized rod-cone dystrophy, whilst one patient with sectoral retinal involvement only had isolated rod dystrophy (20 years old). On follow-up examination (Mean duration: 8.16 years), progressive loss of visual acuity (2/6), mid-peripheral retinal atrophy (3/6) or shortening of ellipsoid zone width (1/6) were observed. CONCLUSION This study has characterized the retinal phenotype in RNU4ATAC-associated Roifman syndrome. Retinal involvement is universal, early-onset, and overall, the retinal and FAF features are consistent with rod-cone degeneration that is slowly progressive over time. The sub-foveal retinal ultrastructure is relatively preserved in majority of patients. Phenotypic variability independent of age exists, and more study of allelic- and sex-based determinants of disease severity are necessary.
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Affiliation(s)
- Brian G Ballios
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
| | - Amarilla Mandola
- Division of Immunology and Allergy, The Hospital for Sick Children and the University of Toronto, Toronto, ON, Canada
| | - Alaa Tayyib
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada
| | - Jenny Garkaby
- Division of Immunology and Allergy, The Hospital for Sick Children and the University of Toronto, Toronto, ON, Canada
| | - Linda Vong
- The Canadian Centre for Primary Immunodeficiency and The Jeffrey Modell Research Laboratory for the Diagnosis of Primary Immunodeficiency, The Hospital for Sick Children, Toronto, ON, Canada
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada
| | - Chaim M Roifman
- Division of Immunology and Allergy, The Hospital for Sick Children and the University of Toronto, Toronto, ON, Canada
- The Canadian Centre for Primary Immunodeficiency and The Jeffrey Modell Research Laboratory for the Diagnosis of Primary Immunodeficiency, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada.
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada.
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2
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Vincent A, Ahmed K, Hussein R, Berberovic Z, Tumber A, Zhao X, Minassian BA. Retinal Phenotyping of a Murine Model of Lafora Disease. Genes (Basel) 2023; 14:genes14040854. [PMID: 37107612 PMCID: PMC10137594 DOI: 10.3390/genes14040854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 04/05/2023] Open
Abstract
Lafora disease (LD) is a progressive neurologic disorder caused by biallelic pathogenic variants in EPM2A or EPM2B, leading to tissue accumulation of polyglucosan aggregates termed Lafora bodies (LBs). This study aimed to characterize the retinal phenotype in Epm2a−/− mice by examining knockout (KO; Epm2a−/−) and control (WT) littermates at two time points (10 and 14 months, respectively). In vivo exams included electroretinogram (ERG) testing, optical coherence tomography (OCT) and retinal photography. Ex vivo retinal testing included Periodic acid Schiff Diastase (PASD) staining, followed by imaging to assess and quantify LB deposition. There was no significant difference in any dark-adapted or light-adapted ERG parameters between KO and WT mice. The total retinal thickness was cFigure mparable between the groups and the retinal appearance was normal in both groups. On PASD staining, LBs were observed in KO mice within the inner and outer plexiform layers and in the inner nuclear layer. The average number of LBs within the inner plexiform layer in KO mice were 1743 ± 533 and 2615 ± 915 per mm2, at 10 and 14 months, respectively. This is the first study to characterize the retinal phenotype in an Epm2a−/− mouse model, demonstrating significant LB deposition in the bipolar cell nuclear layer and its synapses. This finding may be used to monitor the efficacy of experimental treatments in mouse models.
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Affiliation(s)
- Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada
| | - Kashif Ahmed
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Rowaida Hussein
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | | | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Xiaochu Zhao
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Berge A. Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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3
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Dvaladze A, Tavares E, Di Scipio M, Nimmo G, Grudzinska-Pechhacker MK, Paton T, Tumber A, Li S, Eileen C, Ertl-Wagner B, Mamak E, Hoffmann G, Marshall CR, Haas D, Mayatepek E, Schulze A, Heon E, Vincent A. Deep Intronic Variant in MVK as a Cause for Mevalonic Aciduria Initially Presenting as Non-syndromic Retinitis Pigmentosa. Clin Genet 2022; 102:524-529. [PMID: 35916082 DOI: 10.1111/cge.14207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 11/29/2022]
Abstract
Non-syndromic retinitis pigmentosa (NSRP) is a clinically and genetically heterogeneous group of disorders characterized by progressive degeneration of the rod and cone photoreceptors, often leading to blindness. The evolving association of syndromic genes to cause NSRP and the increasing role of intronic variants in explaining missing heritability in genetic disorders present challenges in establishing conclusive clinical and genetic diagnoses. This study sought to identify and validate the causative genetic variant(s) in a 13-year-old male initially diagnosed with NSRP. Genome sequencing identified a pathogenic missense variant in MVK [NM_000431.3:c.803T>C (p. Ile268Thr)], in trans with a novel intronic variant predicted to create a new donor splice site (c.768+71C>A). Proband cDNA analysis confirmed the inclusion of the first 68 base pairs of intron 8 that resulted in a frameshift in MVK (r.768_769ins[768+1_768+68]) and significantly reduced the expression of reference transcript (17.6%). Patient re-phenotyping revealed ataxia, cerebellar atrophy, elevated urinary mevalonate and LTE4 , in keeping with mild mevalonic aciduria and associated syndromic retinitis pigmentosa. Leakage of reference transcript likely explains the milder phenotype observed. This is the first association of a deep intronic splice variant to cause MVK-related disorder. This report highlights the importance of variant validation and patient re-phenotyping in establishing accurate diagnosis in the era of genome sequencing.
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Affiliation(s)
- Anna Dvaladze
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Erika Tavares
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Matteo Di Scipio
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Graeme Nimmo
- Clinical and Metabolic Genetics, HSC, Canada.,Fred A Litwin Family Centre for Genetic Medicine, The University Health Network, Toronto, Canada
| | - Monika K Grudzinska-Pechhacker
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada.,Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
| | - Tara Paton
- The Centre for Applied Genomics, HSC, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
| | - Shuning Li
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Christabel Eileen
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada
| | - Birgit Ertl-Wagner
- Division of Neuroradiology, HSC, Canada.,Department of Medical Imaging, University of Toronto, Canada
| | - Eva Mamak
- Department of Psychology, HSC, Canada
| | - Georg Hoffmann
- Neuropaediatrics and Paediatric Metabolic Medicine, University Hospital Heidelberg, Germany
| | | | - Dorothea Haas
- Neuropaediatrics and Paediatric Metabolic Medicine, University Hospital Heidelberg, Germany
| | - Ertan Mayatepek
- Department of General Paediatrics, Neonatology and Paediatric Cardiology, University Children's Hospital, Heinrich Heine University, Dusseldorf, Germany
| | - Andreas Schulze
- Clinical and Metabolic Genetics, HSC, Canada.,Department of Paediatrics, University of Toronto, Canada.,Department of Biochemistry, University of Toronto, Canada
| | - Elise Heon
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada.,Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genome Biology, The Hospital for Sick Children (HSC), Toronto, Canada.,Department of Ophthalmology and Vision Sciences, HSC and University of Toronto, Canada
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4
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Orsini A, Ferrari D, Riva A, Santangelo A, Macrì A, Freri E, Canafoglia L, D'Aniello A, Di Gennaro G, Massimetti G, Minetti C, Zara F, Michelucci R, Tumber A, Vincent A, Minassian BA, Striano P. Ocular phenotype and electroretinogram abnormalities in Lafora disease and correlation with disease stage. J Neurol 2022; 269:3597-3604. [PMID: 35184210 PMCID: PMC9217906 DOI: 10.1007/s00415-022-10974-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 12/01/2022]
Abstract
Abstract
Background
Lafora disease (LD) is a neurodegenerative disorder featuring action and stimulus-sensitive myoclonus, epilepsy, and cognitive deterioration. Mutations in the EPM2A/EPM2B genes classically prove causative for the disease in most cases. Since full-field electroretinogram (ffERG) may reveal early-stage changes in a wide spectrum of diseases, we aimed to evaluate retinal cones and rods dysfunction in a cohort of Italian LD patients.
Methods
Patients with genetically confirmed LD were recruited and subjected to ffERG analysis following the International Society for Clinical Electrophysiology of Vision (ISCEV) protocol.
Results
Six patients aged between 13 and 26 years (mean 19.5 years) were included. The mean age at disease onset was 12.5 years with a mean disease duration of 7 years. The ffERG analysis revealed a global mild to severe generalized cones dysfunction in all patients. Linear correlation was identified between disease stage and the degree of cones and rods dysfunction, as well as between the type of mutation and the cones and rods dysfunction.
Conclusions
This study brings further evidence of early retinal alterations in LD patients. The cones and rods dysfunction grade is related to disease duration. The ffERG is an important tool to determine the disease stage, allowing to evaluate either natural or treatment-related disease progression in a minimally invasive way.
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Affiliation(s)
- Alessandro Orsini
- Paediatric Neurology, Paediatric Department, Santa Chiara's University Hospital, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | - Daniele Ferrari
- Ophthalmology Unit, Department of Head/Neck Pathologies, Policlinico San Martino Hospital, IRCCS Hospital-University San Martino, Viale Benedetto XV, 16132, Genoa, Italy
| | - Antonella Riva
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health, IRCCS Istituto "G. Gaslini", Via Gaslini 5, 16148, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Andrea Santangelo
- Paediatric Neurology, Paediatric Department, Santa Chiara's University Hospital, Azienda Ospedaliero Universitaria Pisana, Pisa, Italy
| | - Angelo Macrì
- Ophthalmology Unit, Department of Head/Neck Pathologies, Policlinico San Martino Hospital, IRCCS Hospital-University San Martino, Viale Benedetto XV, 16132, Genoa, Italy
| | - Elena Freri
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Laura Canafoglia
- Department of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | | | | | - Gabriele Massimetti
- Section of Psychiatry, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Carlo Minetti
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health, IRCCS Istituto "G. Gaslini", Via Gaslini 5, 16148, Genoa, Italy
| | - Federico Zara
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health, IRCCS Istituto "G. Gaslini", Via Gaslini 5, 16148, Genoa, Italy
| | - Roberto Michelucci
- Unit of Neurology, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bellaria Hospital, Bologna, Italy
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada
| | - Berge Arakel Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health, IRCCS Istituto "G. Gaslini", Via Gaslini 5, 16148, Genoa, Italy.
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.
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5
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Grudzinska Pechhacker MK, Jacobson SG, Drack AV, Scipio MD, Strubbe I, Pfeifer W, Duncan JL, Dollfus H, Goetz N, Muller J, Vincent AL, Aleman TS, Tumber A, Van Cauwenbergh C, De Baere E, Bedoukian E, Leroy BP, Maynes JT, Munier FL, Tavares E, Saleh E, Vincent A, Heon E. Comparative Natural History of Visual Function From Patients With Biallelic Variants in BBS1 and BBS10. Invest Ophthalmol Vis Sci 2021; 62:26. [PMID: 34940782 PMCID: PMC8711006 DOI: 10.1167/iovs.62.15.26] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to compare the natural history of visual function change in cohorts of patients affected with retinal degeneration due to biallelic variants in Bardet-Biedl syndrome genes: BBS1 and BBS10. Methods Patients were recruited from nine academic centers from six countries (Belgium, Canada, France, New Zealand, Switzerland, and the United States). Inclusion criteria were: (1) female or male patients with a clinical diagnosis of retinal dystrophy, (2) biallelic disease-causing variants in BBS1 or BBS10, and (3) measures of visual function for at least one visit. Retrospective data collected included genotypes, age, onset of symptoms, and best corrected visual acuity (VA). When possible, data on refractive error, fundus images and autofluorescence (FAF), optical coherence tomography (OCT), Goldmann kinetic perimetry (VF), electroretinography (ERG), and the systemic phenotype were collected. Results Sixty-seven individuals had variants in BBS1 (n = 38; 20 female patients and 18 male patients); or BBS10 (n = 29; 14 female patients and 15 male patients). Missense variants were the most common type of variants for patients with BBS1, whereas frameshift variants were most common for BBS10. When ERGs were recordable, rod-cone dystrophy (RCD) was observed in 82% (23/28) of patients with BBS1 and 73% (8/11) of patients with BBS10; cone-rod dystrophy (CORD) was seen in 18% of patients with BBS1 only, and cone dystrophy (COD) was only seen in 3 patients with BBS10 (27%). ERGs were nondetectable earlier in patients with BBS10 than in patients with BBS1. Similarly, VA and VF declined more rapidly in patients with BBS10 compared to patients with BBS1. Conclusions Retinal degeneration appears earlier and is more severe in BBS10 cases as compared to those with BBS1 variants. The course of change of visual function appears to relate to genetic subtypes of BBS.
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Affiliation(s)
- Monika K Grudzinska Pechhacker
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Arlene V Drack
- Department of Ophthalmology, Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States
| | - Matteo Di Scipio
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Ine Strubbe
- Department of Ophthalmology, Ghent University Hospital & Department of Head and Skin, Ghent University, Ghent, Belgium
| | - Wanda Pfeifer
- Department of Ophthalmology, Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States
| | - Helene Dollfus
- CARGO ( Centre de référence pour les affections rares génétiques ), IGMA Institut de Génétqiue Médicale d'Alsace , Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,UMRS_1112, IGMA ( Institut de génétique Médicale d'Alsace ) Université de Strasbourg, Strasbourg, France
| | - Nathalie Goetz
- UMRS_1112, IGMA ( Institut de génétique Médicale d'Alsace ) Université de Strasbourg, Strasbourg, France
| | - Jean Muller
- CARGO ( Centre de référence pour les affections rares génétiques ), IGMA Institut de Génétqiue Médicale d'Alsace , Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,UMRS_1112, IGMA ( Institut de génétique Médicale d'Alsace ) Université de Strasbourg, Strasbourg, France.,Laboratoire de diagnostique génétique, IGMA ( Institut de génétique Médicale d'Alsace ) Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Tomas S Aleman
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, Philadelphia, Pennsylvania, United States.,Scheie Eye Institute at the Perelman Center for Advanced Medicine, Philadelphia, Pennsylvania, United States.,Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada
| | - Caroline Van Cauwenbergh
- Department of Ophthalmology, Ghent University Hospital & Department of Head and Skin, Ghent University, Ghent, Belgium.,Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Elfride De Baere
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Emma Bedoukian
- Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
| | - Bart P Leroy
- Department of Ophthalmology, Ghent University Hospital & Department of Head and Skin, Ghent University, Ghent, Belgium.,Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, Philadelphia, Pennsylvania, United States.,Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States.,Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium.,Center for Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
| | - Jason T Maynes
- Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Departments of Biochemistry and Anesthesiology and Pain Medicine, University of Toronto, Program in Molecular Medicine, The Hospital for Sick Children, Toronto, Canada
| | - Francis L Munier
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Erika Tavares
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Eman Saleh
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada.,Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada.,Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
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6
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Leahy KE, Wright T, Grudzinska Pechhacker MK, Audo I, Tumber A, Tavares E, MacDonald H, Locke J, VandenHoven C, Zeitz C, Heon E, Buncic JR, Vincent A. Optic Atrophy and Inner Retinal Thinning in CACNA1F-related Congenital Stationary Night Blindness. Genes (Basel) 2021; 12:genes12030330. [PMID: 33668843 PMCID: PMC7996180 DOI: 10.3390/genes12030330] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/06/2021] [Accepted: 02/20/2021] [Indexed: 12/25/2022] Open
Abstract
Hemizygous pathogenic variants in CACNA1F lead to defective signal transmission from retinal photoreceptors to bipolar cells and cause incomplete congenital stationary night blindness in humans. Although the primary defect is at the terminal end of first-order neurons (photoreceptors), there is limited knowledge of higher-order neuronal changes (inner retinal) in this disorder. This study aimed to investigate inner retinal changes in CACNA1F-retinopathy by analyzing macular ganglion cell layer-inner plexiform layer (GCL-IPL) thickness and optic disc pallor in 22 subjects with molecularly confirmed CACNA1F-retinopathy. Detailed ocular phenotypic data including distance and color vision, refraction and electroretinogram (ERG) were collected. Distance vision was universally reduced (mean: 0.42 LogMAR), six had abnormal color vision and myopia was common (n = 15; mean: −6.32 diopters). Mean GCL-IPL thickness was significantly lower in patients (55.00 µm) compared to age-matched controls (n = 87; 84.57 µm; p << 0.001). The GCL-IPL thickness correlated with scotopic standard (p = 0.04) and bright-flash (p = 0.014) ERG b/a ratios and photopic b-wave amplitudes (p = 0.05). Twenty-one patients had some degree of disc pallor (bilateral in 19). Fifteen putative disease-causing, including five novel variants were identified. This study establishes macular inner retinal thinning and optic atrophy as characteristic features of CACNA1F-retinopathy, which are independent of myopia and could impact potential future treatment strategies.
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Affiliation(s)
- Kate E Leahy
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada;
| | - Tom Wright
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada;
- Kensington Eye Institute, Toronto, ON M5T 3A9, Canada
| | - Monika K Grudzinska Pechhacker
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada;
| | - Isabelle Audo
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, 75012 Paris, France; (I.A.); (C.Z.)
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, 75012 Paris, France
- Institute of Ophthalmology, University College of London, London EC1V 9EL, UK
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
| | - Erika Tavares
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
| | - Heather MacDonald
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Genetic Counselling, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Jeff Locke
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
| | - Cynthia VandenHoven
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
| | - Christina Zeitz
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, 75012 Paris, France; (I.A.); (C.Z.)
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada;
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
| | - J Raymond Buncic
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada;
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; (K.E.L.); (M.K.G.P.); (A.T.); (H.M.); (J.L.); (C.V.); (E.H.); (J.R.B.)
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON M5T 3A9, Canada;
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada;
- Correspondence: ; Tel.: +1-416-813-1500
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7
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Di Scipio M, Tavares E, Deshmukh S, Audo I, Green-Sanderson K, Zubak Y, Zine-Eddine F, Pearson A, Vig A, Tang CY, Mollica A, Karas J, Tumber A, Yu CW, Billingsley G, Wilson MD, Zeitz C, Héon E, Vincent A. Phenotype Driven Analysis of Whole Genome Sequencing Identifies Deep Intronic Variants that Cause Retinal Dystrophies by Aberrant Exonization. Invest Ophthalmol Vis Sci 2021; 61:36. [PMID: 32881472 PMCID: PMC7443117 DOI: 10.1167/iovs.61.10.36] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose To demonstrate the effectiveness of combining retinal phenotyping and focused variant filtering from genome sequencing (GS) in identifying deep intronic disease causing variants in inherited retinal dystrophies. Methods Affected members from three pedigrees with classical enhanced S-cone syndrome (ESCS; Pedigree 1), congenital stationary night blindness (CSNB; Pedigree 2), and achromatopsia (ACHM; Pedigree 3), respectively, underwent detailed ophthalmologic evaluation, optical coherence tomography, and electroretinography. The probands underwent panel-based genetic testing followed by GS analysis. Minigene constructs (NR2E3, GPR179 and CNGB3) and patient-derived cDNA experiments (NR2E3 and GPR179) were performed to assess the functional effect of the deep intronic variants. Results The electrophysiological findings confirmed the clinical diagnosis of ESCS, CSNB, and ACHM in the respective pedigrees. Panel-based testing revealed heterozygous pathogenic variants in NR2E3 (NM_014249.3; c.119-2A>C; Pedigree 1) and CNGB3 (NM_019098.4; c.1148delC/p.Thr383Ilefs*13; Pedigree 3). The GS revealed heterozygous deep intronic variants in Pedigrees 1 (NR2E3; c.1100+1124G>A) and 3 (CNGB3; c.852+4751A>T), and a homozygous GPR179 variant in Pedigree 2 (NM_001004334.3; c.903+343G>A). The identified variants segregated with the phenotype in all pedigrees. All deep intronic variants were predicted to generate a splice acceptor gain causing aberrant exonization in NR2E3 [89 base pairs (bp)], GPR179 (197 bp), and CNGB3 (73 bp); splicing defects were validated through patient-derived cDNA experiments and/or minigene constructs and rescued by antisense oligonucleotide treatment. Conclusions Deep intronic mutations contribute to missing heritability in retinal dystrophies. Combining results from phenotype-directed gene panel testing, GS, and in silico splice prediction tools can help identify these difficult-to-detect pathogenic deep intronic variants.
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Affiliation(s)
- Matteo Di Scipio
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Erika Tavares
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Shriya Deshmukh
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, INSERM-DGOS CIC1423, Paris, France.,University College London Institute of Ophthalmology, London, United Kingdom
| | - Kit Green-Sanderson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Yuliya Zubak
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Fayçal Zine-Eddine
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Alexander Pearson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Anjali Vig
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Chen Yu Tang
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Antonio Mollica
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Jonathan Karas
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada
| | - Caberry W Yu
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Gail Billingsley
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada
| | - Michael D Wilson
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Elise Héon
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
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Grudzinska Pechhacker MK, Di Scipio M, Vig A, Tumber A, Roslin N, Tavares E, Vincent A, Hèon E. CRB1-related retinopathy overlapping the ocular phenotype of S-adenosylhomocysteine hydrolase deficiency. Ophthalmic Genet 2020; 41:457-464. [PMID: 32689861 DOI: 10.1080/13816810.2020.1790013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND S-adenosylhomocysteine hydrolase deficiency due to pathologic variants in AHCY gene is a rare neurometabolic disease for which no eye phenotype has been documented. Pathologic variants in CRB1 gene are known to cause a wide spectrum of autosomal recessive retinal diseases with Leber's congenital amaurosis as a most common. The aim of this study is to report co-inheritance of neurometabolic disease and eye disease in a pedigree. MATERIALS AND METHODS Comprehensive eye examination was performed in available family members together with color vision test, visual fields, fundus images, OCT, electroretinogram and visual evoked potentials. Genetic testing included whole-exome sequencing (WES), retinal dystrophy gene panel and segregation analysis. RESULTS Two children from a family not known to be consanguineous were affected with neurometabolic disease and one of them presented with reduced vision due to maculopathy. The mother had symptoms of retinal degeneration of unspecified cause. Clinical WES revealed homozygous missense pathologic variants in AHCY gene c.148G>A, p.(Ala50Thr) as a cause of S-adenosylhomocysteine hydrolase deficiency. Retinal dystrophy gene panel sequencing revealed two heterozygous missense pathologic variants in CRB1 gene c.1831T>C, p.(Ser611Pro) and c.3955T>C, p.(Phe1319Leu) in the proband and her mother. These variants segregated with disease phenotype in family members. CONCLUSIONS Establishing an ocular genetic diagnosis may be challenging with the co-existence of a rare systemic genetic disease with previously unknown eye involvement. Extensive phenotyping and genotyping of available family members showed that the proband and her mother shared a CRB1-related retinopathy at different stages while the brother did not.
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Affiliation(s)
- Monika K Grudzinska Pechhacker
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children , Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto , Toronto, Canada
| | - Matteo Di Scipio
- Genetics and Genome Biology, The Hospital for Sick Children , Toronto, Canada
| | - Anjali Vig
- Genetics and Genome Biology, The Hospital for Sick Children , Toronto, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children , Toronto, Canada
| | - Nicole Roslin
- Genetics and Genome Biology, The Hospital for Sick Children , Toronto, Canada
| | - Erika Tavares
- Genetics and Genome Biology, The Hospital for Sick Children , Toronto, Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children , Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto , Toronto, Canada.,Genetics and Genome Biology, The Hospital for Sick Children , Toronto, Canada
| | - Elise Hèon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children , Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto , Toronto, Canada.,Genetics and Genome Biology, The Hospital for Sick Children , Toronto, Canada
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9
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Sanderson KG, Millar E, Tumber A, Klatt R, Sondheimer N, Vincent A. Rod bipolar cell dysfunction in POLG retinopathy. Doc Ophthalmol 2020; 142:111-118. [PMID: 32567010 DOI: 10.1007/s10633-020-09777-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/09/2020] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To report the clinical and novel electrophysiological features in a child with POLG-related sensory ataxic neuropathy, dysarthria and ophthalmoparesis (SANDO). METHODS The proband, a male child of Indian descent, underwent serial systemic and ophthalmological evaluations from birth until 14 years of age. Eye examinations included visual acuity and extraocular movement assessments, fundus photography, spectral domain optical coherence tomography and full-field electroretinography (ERG). Detailed genetic testing was also performed. RESULTS The child carried a homozygous mutation in POLG (c.911T > G/p.Leu304Arg) and manifested systemic features such as seizures, headaches, areflexia, hypotonia, myopathy and vomiting. The child's distance visual acuity was 0.50 and 0.40 LogMAR in the right and left eyes, respectively. Bilateral ophthalmoplegia and ptosis were observed at 5 years of age. The dark-adapted (DA) ERG responses to 2.29 cd s m-2 and 7.6 cd s m-2 stimuli showed a markedly reduced b/a ratio; an electronegative configuration was noted to a DA 7.6 ERG. CONCLUSION This is the first documented case of an electronegative ERG in a POLG-related disorder consistent with generalized rod ON-bipolar dysfunction. The rest of the proband's systemic and ophthalmological features were consistent with SANDO but some features overlapped with other POLG-related disorders such as Alpers-Huttenlocher syndrome and autosomal dominant progressive external ophthalmoplegia demonstrating the wide phenotypic overlap expected due to POLG mutations.
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Affiliation(s)
- Kit Green Sanderson
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Eoghan Millar
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Regan Klatt
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Neal Sondheimer
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada.,Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Canada
| | - Ajoy Vincent
- Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada. .,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada.
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10
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Vincent A, Macrì A, Tumber A, Koukas N, Ahonen S, Striano P, Minassian B. Ocular phenotype and electroretinogram abnormalities in Lafora disease: A "window to the brain". Neurology 2018; 91:137-139. [PMID: 29907606 DOI: 10.1212/wnl.0000000000005821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 04/05/2018] [Indexed: 11/15/2022] Open
Affiliation(s)
- Ajoy Vincent
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas
| | - Angelo Macrì
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas
| | - Anupreet Tumber
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas
| | - Nikolas Koukas
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas
| | - Saija Ahonen
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas
| | - Pasquale Striano
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas
| | - Berge Minassian
- From the Hospital for Sick Children (A.V., A.T., S.A., B.M.), Toronto; University of Toronto (A.V.),Canada; Polyclinic Hospital San Martino (A.M.), Genova; University of Genova (N.K., P.S.); G. Gaslini Institute (P.S.), Genova; and University of Texas Southwestern (B.M.), Dallas.
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11
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Vincent A, Ng J, Gerth-Kahlert C, Tavares E, Maynes JT, Wright T, Tiwari A, Tumber A, Li S, Hanson JVM, Bahr A, MacDonald H, Bähr L, Westall C, Berger W, Cremers FPM, den Hollander AI, Héon E. Biallelic Mutations inCRB1Underlie Autosomal Recessive Familial Foveal Retinoschisis. ACTA ACUST UNITED AC 2016; 57:2637-46. [DOI: 10.1167/iovs.15-18281] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Ajoy Vincent
- Program of Genetics and Genome Biology The Hospital for Sick Children, Toronto, Canada 2Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada 3Department of Ophthalmology and Vision Science
| | - Judith Ng
- Program of Genetics and Genome Biology The Hospital for Sick Children, Toronto, Canada
| | | | - Erika Tavares
- Program of Genetics and Genome Biology The Hospital for Sick Children, Toronto, Canada
| | - Jason T. Maynes
- Department of Anesthesia and Pain Medicine, and Program in Molecular Structure and Function, The Hospital for Sick Children, Toronto, Canada
| | - Thomas Wright
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Amit Tiwari
- Institute of Medical Molecular Genetics, University of Zürich, Wagistrasse 12, Schlieren, Switzerland
| | - Anupreet Tumber
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Shuning Li
- Program of Genetics and Genome Biology The Hospital for Sick Children, Toronto, Canada
| | - James V. M. Hanson
- Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland
| | - Angela Bahr
- Institute of Medical Molecular Genetics, University of Zürich, Wagistrasse 12, Schlieren, Switzerland
| | - Heather MacDonald
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada 7Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada 8Division of Clinical and Metabolic Genetics, The Ho
| | - Luzy Bähr
- Institute of Medical Molecular Genetics, University of Zürich, Wagistrasse 12, Schlieren, Switzerland
| | - Carol Westall
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada 3Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zürich, Wagistrasse 12, Schlieren, Switzerland 9Zurich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zürich, Switzerland 10Neuroscience Center Zurich (ZNZ), University and ETH
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Anneke I. den Hollander
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands 12Department of Ophthalmology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Elise Héon
- Program of Genetics and Genome Biology The Hospital for Sick Children, Toronto, Canada 2Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada 3Department of Ophthalmology and Vision Science
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12
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Vincent A, Audo I, Tavares E, Maynes J, Tumber A, Wright T, Li S, Michiels C, Condroyer C, MacDonald H, Verdet R, Sahel JA, Hamel CP, Zeitz C, Héon E, Banin E, Bocquet B, De Baere E, Casteels I, Defoort-Dhellemmes S, Drumare I, Friedburg C, Gottlob I, Jacobson S, Kellner U, Koenekoop R, Kohl S, Leroy B, Lorenz B, McLean R, Meire F, Meunier I, Munier F, de Ravel T, Reiff C, Mohand-Saïd S, Sharon D, Schorderet D, Schwartz S, Zanlonghi X. Biallelic Mutations in GNB3 Cause a Unique Form of Autosomal-Recessive Congenital Stationary Night Blindness. Am J Hum Genet 2016; 98:1011-1019. [PMID: 27063057 DOI: 10.1016/j.ajhg.2016.03.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/18/2016] [Indexed: 01/13/2023] Open
Abstract
Congenital stationary night blindness (CSNB) is a heterogeneous group of non-progressive inherited retinal disorders with characteristic electroretinogram (ERG) abnormalities. Riggs and Schubert-Bornschein are subtypes of CSNB and demonstrate distinct ERG features. Riggs CSNB demonstrates selective rod photoreceptor dysfunction and occurs due to mutations in genes encoding proteins involved in rod phototransduction cascade; night blindness is the only symptom and eye examination is otherwise normal. Schubert-Bornschein CSNB is a consequence of impaired signal transmission between the photoreceptors and bipolar cells. Schubert-Bornschein CSNB is subdivided into complete CSNB with an ON bipolar signaling defect and incomplete CSNB with both ON and OFF pathway involvement. Both subtypes are associated with variable degrees of night blindness or photophobia, reduced visual acuity, high myopia, and nystagmus. Whole-exome sequencing of a family screened negative for mutations in genes associated with CSNB identified biallelic mutations in the guanine nucleotide-binding protein subunit beta-3 gene (GNB3). Two siblings were compound heterozygous for a deletion (c.170_172delAGA [p.Lys57del]) and a nonsense mutation (c.1017G>A [p.Trp339(∗)]). The maternal aunt was homozygous for the nonsense mutation (c.1017G>A [p.Trp339(∗)]). Mutational analysis of GNB3 in a cohort of 58 subjects with CSNB identified a sporadic case individual with a homozygous GNB3 mutation (c.200C>T [p.Ser67Phe]). GNB3 encodes the β subunit of G protein heterotrimer (Gαβγ) and is known to modulate ON bipolar cell signaling and cone transducin function in mice. Affected human subjects showed an unusual CSNB phenotype with variable degrees of ON bipolar dysfunction and reduced cone sensitivity. This unique retinal disorder with dual anomaly in visual processing expands our knowledge about retinal signaling.
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13
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Thinnes CC, Tumber A, Yapp C, Scozzafava G, Yeh T, Chan MC, Tran TA, Hsu K, Tarhonskaya H, Walport LJ, Wilkins SE, Martinez ED, Müller S, Pugh CW, Ratcliffe PJ, Brennan PE, Kawamura A, Schofield CJ. Betti reaction enables efficient synthesis of 8-hydroxyquinoline inhibitors of 2-oxoglutarate oxygenases. Chem Commun (Camb) 2015; 51:15458-61. [PMID: 26345662 DOI: 10.1039/c5cc06095h] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2024]
Abstract
There is interest in developing potent, selective, and cell-permeable inhibitors of human ferrous iron and 2-oxoglutarate (2OG) oxygenases for use in functional and target validation studies. The 3-component Betti reaction enables efficient one-step C-7 functionalisation of modified 8-hydroxyquinolines (8HQs) to produce cell-active inhibitors of KDM4 histone demethylases and other 2OG oxygenases; the work exemplifies how a template-based metallo-enzyme inhibitor approach can be used to give biologically active compounds.
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Affiliation(s)
- C C Thinnes
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
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Abstract
Programmed cell death (PCD) or apoptosis is a naturally occurring cell suicide pathway induced in a variety of cell types. We determined whether ceramide treatment contributes to reduced cell viability and increased PCD in primary osteoblasts and the signalling pathways that are involved. Cell viability was determined by the 3-(4,5-dimethyl-thiozol-2-yl)-2,5-diphenyl tetrazolium bromide assay. We found that C(2)-ceramide (<or=10(-7) M) promoted osteoblast viability, whilst concentrations >or=2 x 10(-6) M significantly reduced osteoblast viability in a dose- and time-dependent manner. The effect of ceramide on cell viability was specific since C(2)-dihydroceramide had no effect. Increasing intracellular ceramide levels with either sphingomyelinase (SMase) or an inhibitor of ceramide metabolism also increased osteoblast apoptosis. Ceramide-induced PCD in osteoblasts was determined by nuclear appearance and DNA fragmentation. PCD was induced by both C(2)-ceramide and SMase. The ability of ceramide (5 x 10(-8) M) to promote osteoblast survival was prevented by a general protein kinase C (PKC) inhibitor and by a PKC zeta inhibitor, whilst osteoblast survival was enhanced in the presence of a protein phosphatase 1 (PP1) inhibitor. Phosphatidylinositol-3 kinase (PI3K) inhibitors had no effect on osteoblast survival. The ability of ceramide (5 x 10(-5) M) to induce apoptosis was prevented by the inhibitors of PP1 and PKC delta, whilst the general PKC and PI3K inhibitors had no effect on it. Our findings suggest that ceramide signals osteoblast survival and apoptosis through different intracellular pathways, and that alteration in the intracellular levels of ceramide may play an important role in bone remodelling.
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Affiliation(s)
- P A Hill
- Department of Craniofacial Development and Orthodontics, Kings College London, GKT Dental Institute, London SE1 9RT, UK.
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Abstract
The aims of this study were to identify the role and sites of action of serine proteinases (SPs) in bone resorption, a process which involves a cascade of events, the central step of which is the removal of bone matrix by osteoclasts (OCs). This resorbing activity, however, is also determined by recruitment of new OCs to future resorption sites and removal of the osteoid layer by osteoblasts (OBs), which enables OCs to gain access to the underlying mineralized bone. The resorption systems we have studied consisted of (i) neonatal calvarial explants, (ii) isolated OCs cultured on ivory slices, (iii) mouse OBs cultured on either radiolabelled type I collagen films or bone-like matrix, (iv) bone marrow cultures to assess OC formation and (v) 17-day-old fetal mouse metatarsal bone rudiments to assess OC migration and fusion. Two separate SP inhibitors, aprotinin and alpha(2)-antiplasmin dose-dependently inhibited (45)Ca release from neonatal calvarial explants: aprotinin (10(-6) M) was the most effective SP inhibitor, producing a maximum inhibitory effect of 55.9%. Neither of the SP inhibitors influenced either OC formation or OC resorptive activity. In contrast, each SP inhibitor dose-dependently inhibited OB-mediated degradation of both type I collagen fibrils and non-mineralized bone matrix. In 17-day-old metatarsal explants aprotinin produced a 55% reduction in the migration of OCs from the periosteum to the mineralized matrix after 3 days in culture but after 6 days in culture aprotinin was without effect on OC migration. Primary mouse osteoblasts expressed mRNA for urokinase type plasminogen activator (uPA), tIssue type plasminogen activator (tPA), the type I receptor for uPA, plasminogen activator inhibitor types I and II and the broad spectrum serine proteinase inhibitor, protease nexin I. In situ hybridization demonstrated expression of tPA and uPA in osteoclasts disaggregated from 6-day-old mouse long bones. We propose that the regulation of these various enzyme systems within bone tIssue determines the sites where bone resorption will be initiated.
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Affiliation(s)
- A Tumber
- Department of Orthodontics and Paediatric Dentistry, United Medical and Dental Schools of Guy's, King's and St Thomas' Hospitals, University of London, London SE1 9RT, UK
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Abstract
A central event in bone resorption is the recruitment of osteoclasts to future resorption sites. Breast-cancer cells invariably metastasise to the skeleton and induce extensive bone destruction by osteoclasts. However, our understanding of the mechanisms by which cancer cells interact with osteoclasts remains unclear. Consequently, we compared the effects of conditioned medium (CM) from 2 human breast-cancer cell lines, MB-MDA-231 and MCF-7, with those of a normal human breast epithelial cell line, HME, on osteoclastic fusion, resorptive activity and migration from the periosteum to the developing marrow cavity of fetal mouse metatarsals in culture. Osteoclastic resorptive activity was assessed by pre-labelling 17-day-old fetal metatarsal explants with 45Ca, whilst fusion and migration were monitored by histomorphometry and osteoclasts were identified by their tartrate-resistant acid phosphatase activity. CM from TPA-stimulated breast-cancer cell lines produced a significant increase in osteoclastic resorptive activity, whilst the normal breast cell line produced a minimal increase. The breast-cancer cell lines also stimulated osteoclastic fusion and migration in the metatarsal explants, but the normal breast cell line was without effect. The stimulatory effect of CM from MDA-MB-231 cells on osteoclastic fusion, but not migration, was partially inhibited by preventing prostaglandin and leukotriene synthesis by cells within the bone explants. In contrast, a synthetic matrix metalloproteinase (MMP) inhibitor, but not a cysteine proteinase inhibitor, prevented the migration of osteoclasts to the calcified centre of the metatarsal explants in response to CM from MDA-MB-231 cells. MDA-MB-231 cells also induced an increase in the expression of MMP-9 by migrating osteoclasts. Fractionation of the TPA-stimulated breast cancer cell CM established that the resorptive activity was associated with factors of m.w. >3 kDa. We determined by immuno-assay that human breast-cancer cells secrete parathyroid hormone-related protein (PTH-rP), tumour necrosis factor-alpha (TNF-alpha) and interleukins (ILs) 6 and 11. Neutralizing experiments with human antibodies to these cytokines established that PTH-rP and TNF-alpha production by MDA-MB-231 cells were responsible for mediating their effects on osteoclastic migration and ultimately bone resorption in the metatarsal explants.
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Affiliation(s)
- A Tumber
- Bone Biology Unit, Department of Orthodontics and Paediatric Dentistry, Guy's, King's and St. Thomas' School of Medicine and Dentistry, Guy's Hospital, London, United Kingdom
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17
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Abstract
We have studied the survival requirements of osteoblasts to test the hypothesis that osteoblasts undergo programmed cell death (PCD) or apoptosis unless they are continuously signalled by other cells not to do so. Osteoblasts survived for 6 days in culture at high cell density in the absence of other cell types, serum or exogenous proteins, but they died with the morphological features of apoptosis in these conditions at low cell density. Osteoblast survival was enhanced during the first 2 days of culture by the addition of the sulphydryl compound, cysteine to the culture medium which was converted intracellularly to the antioxidant glutathione. Catalase, an enzyme decomposing hydrogen peroxide, also protected the cells, whereas superoxide dismutase had no effect. Therefore, osteoblasts in culture are sensitive to toxic compounds derived from molecular oxygen, i.e. hydroxyl radicals or hydrogen peroxide spontaneously generated in CMRL medium containing ascorbate and ferrous ions. Conditioned medium from high density cultures prevented osteoblast apoptosis in low density cultures, as long as antioxidants were also present. The enhancing effect of conditioned medium on osteoblast survival was prevented by neutralizing antibodies to insulin-like growth factor-I (IGF-I) and IGF-II but not by antibodies to either platelet-derived growth factor (PDGF) or basic fibroblast growth factor (bFGF). These results suggest that in addition to regulating cell growth and differentiation, IGF-I and IGF-II also function as survival factors for osteoblasts. Our data also indicate that antioxidants are required for osteoblast survival and that they enhance growth factor mediated osteoblast survival.
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Affiliation(s)
- A Tumber
- Bone Biology Unit, Department of Orthodontics and Paediatric Dentistry, Guy's, King's and St Thomas' Hospital's Medical and Dental Schools, Guy's Hospital, St Thomas' Street, London SE1 9RT, UK
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18
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Breckon JJ, Papaioannou S, Kon LW, Tumber A, Hembry RM, Murphy G, Reynolds JJ, Meikle MC. Stromelysin (MMP-3) synthesis is up-regulated in estrogen-deficient mouse osteoblasts in vivo and in vitro. J Bone Miner Res 1999; 14:1880-90. [PMID: 10571688 DOI: 10.1359/jbmr.1999.14.11.1880] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Sex steroids are important regulators of bone cell function and osteoblast-derived matrix metalloproteinases (MMPs) are key mediators of bone resorption during the initial stage of osteoid removal prior to osteoclast attachment. To investigate the mechanism of bone loss following estrogen deficiency, we examined the effects of estrogen on osteoblast synthesis of MMPs and tissue inhibitor of metalloproteinases (TIMPs). Immunolocalization in mouse bone samples ex vivo and primary mouse osteoblast (MOB) cultures was used to document the synthesis of mouse interstitial collagenase (MMP-13), stromelysin-1 (MMP-3), gelatinase-A (MMP-2), and gelatinase-B (MMP-9). Endosteal bone lining cells from distal femoral head and lumbar vertebral body showed an increase in the pattern of synthesis of stromelysin-1 following ovariectomy, compared with sham-operated controls; the synthesis of other MMPs was unaffected. The expression of all classes of MMPs and TIMP-1 and TIMP-2 by MOB in culture was demonstrated by reverse transcriptase-polymerase chain reaction. Following the withdrawal of 17beta-estradiol, MOB cultures showed a significant increase in the number of cells synthesizing stromelysin-1; this effect was enhanced by stimulation with either interleukin-1 or interleukin-6. Northern blot analysis showed only a slight increase in stromelysin-1 mRNA message following the withdrawal of 17beta-estradiol. Our data show an unexpected up-regulation of stromelysin-1 synthesis by osteoblasts both in vivo and in vitro following estrogen withdrawal. Although this effect was not reflected in a significant change in stromelysin-1 mRNA expression in vitro, there is evidence to suggest a role for this enzyme in the early stages of bone loss during the pathogenesis of osteoporosis.
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Affiliation(s)
- J J Breckon
- Bone Biology Unit, Department of Orthodontics, GKT School of Medicine and Dentistry, Guy's Hospital, London, United Kingdom
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19
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Abstract
The pleiotropic cytokine interleukin-11 (IL-11) stimulates osteoclast formation in vitro, but it is not known whether it influences other steps in the bone-resorptive cascade. Using a variety of in vitro model systems for studying bone resorption we have investigated the effects of IL-11 on 1) osteoclast formation, fusion, migration, and activity; and 2) osteoblast-mediated osteoid degradation. The involvement of matrix metalloproteinases (MMPs) and products of arachidonic acid metabolism in IL-11-mediated resorption were also assessed. We first examined the bone-resorptive effects of IL-11 by assessing 45Ca release from neonatal mouse calvarial bones. IL-11 dose-dependently stimulated bone resorption with an EC50 of 10(-10) M. The kinetics of IL-11-mediated 45Ca release demonstrated that it was without effect for the first 48 h of culture, but by 96 h, it stimulated 45Ca release to the same level as that produced by 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] (a hormone that stimulates osteoclast formation and activity). IL-11 also produced a dose-dependent increase in osteoblast-mediated type I collagen degradation with a maximum of 58.0 +/- 6.2% at 5 x 10(-9) M; this effect of IL-11 was less than that produced by 1,25-(OH)2D3 (76.5 +/- 7.1%) and was prevented by an inhibitor of MMPs, but not those blocking arachidonic acid metabolism. We then tested the effects of IL-11 on isolated mouse osteoclasts cultured on ivory slices in the presence and absence of primary mouse osteoblasts. IL-11 had no effect on isolated osteoclast activity even in coculture with primary osteoblasts. We then examined the effects of IL-11 on the formation of osteoclast-like multinucleate cells in mouse bone marrow cultures and the resorptive activity of such cultures using ivory as a substrate. IL-11 dose-dependently increased 1) the number of tartrate-resistant acid phosphatase-positive osteoclast-like multinucleate cells and 2) the surface area of lacunar resorption, although the effects were less than that of 1,25-(OH)2D3. The effect of IL-11 on bone marrow lacunar resorption was prevented by a combination of inhibitors of 5-lipoxygenase and cyclooxygenase. In 17-day-old metatarsal bones, IL-11 prevented the migration of (pre)osteoclasts to future resorption sites, whereas their fusion was unaffected. These results provide strong evidence that IL-11 stimulates bone resorption by enhancing osteoclast formation and osteoblast-mediated osteoid degradation rather than stimulating osteoclast migration and activity. Our data also suggest that the stimulatory effects of IL-11 involve both MMPs and products of arachidonic acid metabolism.
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Affiliation(s)
- P A Hill
- Department of Orthodontics, United Medical and Dental Schools of Guy's and St. Thomas' Hospitals, University of London, United Kingdom
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20
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Abstract
Programed cell death (PCD) or apoptosis is a naturally occurring cell suicide pathway induced in a variety of cell types. In many cases, PCD apparently arises as a result of competition for limiting amounts of survival signals. In this study, we have investigated the potential role of growth factors (GF), cytokines, and osteotropic hormones on osteoblast survival in vitro. Our results indicate that in the absence of any of these factors, osteoblasts rapidly undergo PCD, as determined by cell morphology, mitochondrial function, and nuclei fragmentation. Osteoblast survival was promoted by insulin-like growth factor I (IGF-I), IGF-II, insulin, and basic fibroblast growth factor (bFGF). Platelet-derived growth factor had no effect on osteoblast survival, but this GF potentiated the survival-promoting effects of IGF-I, IGF-II, and insulin. A similar effect occurred when bFGF was added in combination with either of the IGFs or insulin. The effects of the IGFs were blocked by alphaIR-3, an antibody to the type I IGF receptor, whereas the effects of insulin were only partially blocked. This antibody blocked the potentiating effects of platelet-derived growth factor on IGF-I-mediated osteoblast survival, but only partially blocked those of bFGF. Although a 100% survival of osteoblasts was seen in the presence of 2% FCS, the highest level attained by any of the above GF combinations was approximately 75%. The monocyte-derived factor, tumor necrosis factor-alpha (TNF alpha) was the only agent that enhanced PCD in this study. These results suggest that osteoblast survival is promoted by those GFs sequestrated in bone matrix and that the type I, but not the type II, IGF receptor is involved in the response. Our data also indicate that other unidentified GFs or components of the extracellular matrix may be involved in promoting osteoblast survival and that TNF alpha may abrogate their effects in vivo. We propose that these GFs may be released from bone matrix during phases of bone resorption and promote osteoblast survival, thereby playing an important role in bone remodeling, and that PCD induced by TNF alpha may contribute to the bone loss in inflammatory bone disease.
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Affiliation(s)
- P A Hill
- Department of Orthodontics and Pediatric Dentistry, United Medical and Dental Schools of Guy's and St. Thomas' Hospitals, University of London, United Kingdom
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