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Loreto A, Merlini E, Coleman MP. Programmed axon death: a promising target for treating retinal and optic nerve disorders. Eye (Lond) 2024; 38:1802-1809. [PMID: 38538779 PMCID: PMC11226669 DOI: 10.1038/s41433-024-03025-0] [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: 09/04/2023] [Revised: 02/13/2024] [Accepted: 03/08/2024] [Indexed: 07/07/2024] Open
Abstract
Programmed axon death is a druggable pathway of axon degeneration that has garnered considerable interest from pharmaceutical companies as a promising therapeutic target for various neurodegenerative disorders. In this review, we highlight mechanisms through which this pathway is activated in the retina and optic nerve, and discuss its potential significance for developing therapies for eye disorders and beyond. At the core of programmed axon death are two enzymes, NMNAT2 and SARM1, with pivotal roles in NAD metabolism. Extensive preclinical data in disease models consistently demonstrate remarkable, and in some instances, complete and enduring neuroprotection when this mechanism is targeted. Findings from animal studies are now being substantiated by genetic human data, propelling the field rapidly toward clinical translation. As we approach the clinical phase, the selection of suitable disorders for initial clinical trials targeting programmed axon death becomes crucial for their success. We delve into the multifaceted roles of programmed axon death and NAD metabolism in retinal and optic nerve disorders. We discuss the role of SARM1 beyond axon degeneration, including its potential involvement in neuronal soma death and photoreceptor degeneration. We also discuss genetic human data and environmental triggers of programmed axon death. Lastly, we touch upon potential therapeutic approaches targeting NMNATs and SARM1, as well as the nicotinamide trials for glaucoma. The extensive literature linking programmed axon death to eye disorders, along with the eye's suitability for drug delivery and visual assessments, makes retinal and optic nerve disorders strong contenders for early clinical trials targeting programmed axon death.
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Affiliation(s)
- Andrea Loreto
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
- School of Medical Sciences and Save Sight Institute, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
| | - Elisa Merlini
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
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2
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Moya R, Angée C, Hanein S, Jabot-Hanin F, Kaplan J, Perrault I, Rozet JM, Fares Taie L. Four Unique Genetic Variants in Three Genes Account for 62.7% of Early-Onset Severe Retinal Dystrophy in Chile: Diagnostic and Therapeutic Consequences. Int J Mol Sci 2024; 25:6151. [PMID: 38892339 PMCID: PMC11172861 DOI: 10.3390/ijms25116151] [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: 04/04/2024] [Revised: 05/29/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
Leber congenital amaurosis (LCA)/early-onset severe retinal dystrophy (EOSRD) stand as primary causes of incurable childhood blindness. This study investigates the clinical and molecular architecture of syndromic and non-syndromic LCA/EOSRD within a Chilean cohort (67 patients/60 families). Leveraging panel sequencing, 95.5% detection was achieved, revealing 17 genes and 126 variants (32 unique). CRB1, LCA5, and RDH12 dominated (71.9%), with CRB1 being the most prevalent (43.8%). Notably, four unique variants (LCA5 p.Glu415*, CRB1 p.Ser1049Aspfs*40 and p.Cys948Tyr, RDH12 p.Leu99Ile) constituted 62.7% of all disease alleles, indicating their importance for targeted analysis in Chilean patients. This study underscores a high degree of inbreeding in Chilean families affected by pediatric retinal blindness, resulting in a limited mutation repertoire. Furthermore, it complements and reinforces earlier reports, indicating the involvement of ADAM9 and RP1 as uncommon causes of LCA/EOSRD. These data hold significant value for patient and family counseling, pharmaceutical industry endeavors in personalized medicine, and future enrolment in gene therapy-based treatments, particularly with ongoing trials (LCA5) or advancing preclinical developments (CRB1 and RDH12).
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Affiliation(s)
- Rene Moya
- Department of Ophthalmology, Hospital del Salvador, Universidad de Chile, Santiago 7500922, Chile;
| | - Clémentine Angée
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France (I.P.)
| | - Sylvain Hanein
- Bioinformatic Platform, INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France
| | - Fabienne Jabot-Hanin
- Bioinformatic Platform, INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France
| | - Josseline Kaplan
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France (I.P.)
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France (I.P.)
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France (I.P.)
| | - Lucas Fares Taie
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris Descartes University, 75015 Paris, France (I.P.)
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Villafuerte-de la Cruz RA, Garza-Garza LA, Garza-Leon M, Rodriguez-De la Torre C, Parra-Bernal C, Vazquez-Camas I, Ramos-Gonzalez D, Rangel-Padilla A, Espino Barros-Palau A, Nava-García J, Castillo-Velazquez J, Castillo-De Leon E, Del Valle-Penella A, Valdez-Garcia JE, Rojas-Martinez A. Spectrum of variants associated with inherited retinal dystrophies in Northeast Mexico. BMC Ophthalmol 2024; 24:60. [PMID: 38347443 PMCID: PMC10860328 DOI: 10.1186/s12886-023-03276-7] [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: 08/30/2023] [Accepted: 12/26/2023] [Indexed: 02/15/2024] Open
Abstract
BACKGROUND Inherited retinal dystrophies are hereditary diseases which have in common the progressive degeneration of photoreceptors. They are a group of diseases with clinical, genetic, and allelic heterogeneity. There is limited information regarding the genetic landscape of inherited retinal diseases in Mexico, therefore, the present study was conducted in the northeast region of the country. METHODS Patients with inherited retinal dystrophies were included. A complete history, full ophthalmological and medical genetics evaluations, and genetic analysis through a targeted NGS panel for inherited retinal dystrophies comprising at least 293 genes were undertaken. RESULTS A total of 126 patients were included. Cases were solved in 74.6% of the study's population. Retinitis pigmentosa accounted for the most found inherited retinal disease. Ninety-nine causal variants were found, being USH2A and ABCA4 the most affected genes (26 and 15 cases, respectively). CONCLUSIONS The present study documents the most prevalent causative genes in IRDs, as USH2A, in northeastern Mexico. This contrasts with previous reports of IRDs in other zones of the country. Further studies, targeting previously unstudied populations in Mexico are important to document the genetic background of inherited retinal dystrophies in the country.
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Affiliation(s)
- Rocio A Villafuerte-de la Cruz
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
- Destellos de Luz, San Pedro Garza García, México
| | | | - Manuel Garza-Leon
- Destellos de Luz, San Pedro Garza García, México
- Clinical Science Department, Health Sciences Division, University of Monterrey, Monterrey, México
| | - Cesar Rodriguez-De la Torre
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | - Cinthya Parra-Bernal
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | - Ilse Vazquez-Camas
- Tecnologico de Monterrey, The Institute for Obesity Research, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
- Tecnologico Nacional de Mexico Campus Tuxtla Gutierrez, Tuxtla Gutierrez, Mexico
| | - David Ramos-Gonzalez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | - Andrea Rangel-Padilla
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | - Angelina Espino Barros-Palau
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | - Jose Nava-García
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | | | | | | | - Jorge E Valdez-Garcia
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico
| | - Augusto Rojas-Martinez
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de La Salud, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico.
- Tecnologico de Monterrey, The Institute for Obesity Research, Ave. Morones Prieto 3000, Col. Los Doctores, Monterrey, CP 64710, Mexico.
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Kuo CY, Chung MY, Chen SJ. Pseudocoloboma-like maculopathy with biallelic RDH12 missense mutations. J Med Genet 2023; 60:859-865. [PMID: 36690427 PMCID: PMC10447408 DOI: 10.1136/jmg-2022-108918] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 01/02/2023] [Indexed: 01/25/2023]
Abstract
BACKGROUND Hereditary maculopathy is a group of clinically and genetically heterogeneous disorders. With distinctive clinical features, subtypes of macular atrophy may correlate with their genetic defects. METHODS Seven patients from six families with adolescent/adult-onset maculopathy were examined in this clinical case series. A detailed medical history and eye examination were performed. Genomic DNA sequencing was performed using whole exome sequencing or direct sequencing of retinol dehydrogenase 12 (RDH12) coding exons. RESULTS Seven patients, including one male and six female patients, with pseudocoloboma-like maculopathy had biallelic missense RDH12 mutations. The most common mutant allele found in six of the seven patients was p.Ala269Gly. The average disease onset was at age 19.3 years, and visual acuity ranged from count fingers to 1.0. Most of the patients had mild myopic refraction. Common findings on fundus examination and spectral-domain optical coherence tomography include discrete margins of pseudocoloboma-like macular lesions with variable degrees of chorioretinal atrophy, excavation of retinal tissue and pigmentary changes mainly in the macular area. The electroretinograms were relatively normal to subnormal in all participants. CONCLUSIONS Progressive macular degeneration with a relatively normal peripheral retina and subsequent development of a pseudocoloboma-like appearance were the main clinical features in patients with compound heterozygous RDH12 missense mutations. Genetic testing may be crucial for early diagnosis and may play a key role in the development of future treatment strategies.
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Affiliation(s)
- Che-Yuan Kuo
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Ophthalmology, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ming-Yi Chung
- Department of Life Sciences & Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shih-Jen Chen
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Ophthalmology, National Yang Ming Chiao Tung University, Taipei, Taiwan
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5
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Ju WK, Perkins GA, Kim KY, Bastola T, Choi WY, Choi SH. Glaucomatous optic neuropathy: Mitochondrial dynamics, dysfunction and protection in retinal ganglion cells. Prog Retin Eye Res 2023; 95:101136. [PMID: 36400670 DOI: 10.1016/j.preteyeres.2022.101136] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/04/2022] [Accepted: 11/03/2022] [Indexed: 11/18/2022]
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by a slow, progressive, and multifactorial degeneration of retinal ganglion cells (RGCs) and their axons, resulting in vision loss. Despite its high prevalence in individuals 60 years of age and older, the causing factors contributing to glaucoma progression are currently not well characterized. Intraocular pressure (IOP) is the only proven treatable risk factor. However, lowering IOP is insufficient for preventing disease progression. One of the significant interests in glaucoma pathogenesis is understanding the structural and functional impairment of mitochondria in RGCs and their axons and synapses. Glaucomatous risk factors such as IOP elevation, aging, genetic variation, neuroinflammation, neurotrophic factor deprivation, and vascular dysregulation, are potential inducers for mitochondrial dysfunction in glaucoma. Because oxidative phosphorylation stress-mediated mitochondrial dysfunction is associated with structural and functional impairment of mitochondria in glaucomatous RGCs, understanding the underlying mechanisms and relationship between structural and functional alterations in mitochondria would be beneficial to developing mitochondria-related neuroprotection in RGCs and their axons and synapses against glaucomatous neurodegeneration. Here, we review the current studies focusing on mitochondrial dynamics-based structural and functional alterations in the mitochondria of glaucomatous RGCs and therapeutic strategies to protect RGCs against glaucomatous neurodegeneration.
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Affiliation(s)
- Won-Kyu Ju
- Hamilton Glaucoma Center and Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Tonking Bastola
- Hamilton Glaucoma Center and Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, 92093, USA
| | - Woo-Young Choi
- Hamilton Glaucoma Center and Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, 92093, USA; Department of Plastic Surgery, College of Medicine, Chosun University, Gwang-ju, South Korea
| | - Soo-Ho Choi
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
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6
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Brown EE, Scandura MJ, Pierce EA. Expression of NMNAT1 in the photoreceptors is sufficient to prevent NMNAT1-associated retinal degeneration. Mol Ther Methods Clin Dev 2023; 29:319-328. [PMID: 37214313 PMCID: PMC10193288 DOI: 10.1016/j.omtm.2023.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 04/12/2023] [Indexed: 05/24/2023]
Abstract
Nicotinamide nucleotide adenylyltransferase 1 (NMNAT1) is a ubiquitously expressed enzyme involved in nuclear NAD+ production throughout the body. However, mutations in the NMNAT1 gene lead to retina-specific disease with few reports of systemic effects. We have previously demonstrated that AAV-mediated gene therapy using self-complementary AAV (scAAV) to ubiquitously express NMNAT1 throughout the retina prevents retinal degeneration in a mouse model of NMNAT1-associated disease. We aimed to develop a better understanding of the cell types in the retina that contribute to disease pathogenesis in NMNAT1-associated disease, and to identify the cell types that require NMNAT1 expression for therapeutic benefit. To achieve this goal, we treated Nmnat1V9M/V9M mice with scAAV using cell type-specific promoters to restrict NMNAT1 expression to distinct retinal cell types. We hypothesized that photoreceptors are uniquely vulnerable to NAD+ depletion due to mutations in NMNAT1. Consistent with this hypothesis, we identified that treatments that drove NMNAT1 expression in the photoreceptors led to preservation of retinal morphology. These findings suggest that gene therapies for NMNAT1-associated disease should aim to express NMNAT1 in the photoreceptor cells.
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Affiliation(s)
- Emily E. Brown
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Harvard Medical School, Boston, MA 02114, USA
| | - Michael J. Scandura
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Harvard Medical School, Boston, MA 02114, USA
| | - Eric A. Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Harvard Medical School, Boston, MA 02114, USA
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7
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Skorczyk-Werner A, Sowińska-Seidler A, Wawrocka A, Walczak-Sztulpa J, Krawczyński MR. Molecular background of Leber congenital amaurosis in a Polish cohort of patients-novel variants discovered by NGS. J Appl Genet 2023; 64:89-104. [PMID: 36369640 PMCID: PMC9837007 DOI: 10.1007/s13353-022-00733-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/05/2022] [Accepted: 10/12/2022] [Indexed: 11/13/2022]
Abstract
Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophies and the most frequent cause of congenital blindness in children. To date, 25 genes have been implicated in the pathogenesis of this rare disorder. Performing an accurate molecular diagnosis is crucial as gene therapy is becoming available. This study aimed to report the molecular basis of Leber congenital amaurosis, especially novel and rare variants in 27 Polish families with a clinical diagnosis of LCA fully confirmed by molecular analyses. Whole exome sequencing or targeted next-generation sequencing (NGS) of inherited retinal dystrophies-associated (IRD) genes was applied to identify potentially pathogenic variants. Bidirectional Sanger sequencing and quantitative PCR (qPCR) were carried out for validation and segregation analysis of the variants identified within the families. We identified 28 potentially pathogenic variants, including 11 novel, in 8 LCA genes: CEP290, CRB1, GUCY2D, NMNAT1, RPGRIP1, CRX, LRAT1, and LCA5. This study expands the mutational spectrum of the LCA genes. Moreover, these results, together with the conclusions from our previous studies, allow us to point to the most frequently mutated genes and variants in the Polish cohort of LCA patients.
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Affiliation(s)
- Anna Skorczyk-Werner
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland.
| | - Anna Sowińska-Seidler
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Anna Wawrocka
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | | | - Maciej Robert Krawczyński
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
- Centers for Medical Genetics GENESIS, Poznan, Poland
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Brown EE, Scandura MJ, Pierce E. Role of Nuclear NAD + in Retinal Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:235-239. [PMID: 37440039 DOI: 10.1007/978-3-031-27681-1_34] [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
The retina is one of the most metabolically active tissues and maintenance of metabolic homeostasis is critical for retinal function. Nicotinamide adenine dinucleotide (NAD+) is a cofactor that is required for key processes, including the electron transport chain, glycolysis, fatty acid oxidation, and redox reactions. NAD+ also acts as a co-substrate for enzymes involved in maintaining genomic DNA integrity and cellular homeostasis, including poly-ADP ribose polymerases (PARPs) and Sirtuins. This review highlights the importance of NAD+ in the retina, including the role of enzymes involved in NAD+ production in the retina and how NAD+-consuming enzymes may play a role in disease pathology. We also suggest a cell death pathway that may be common in multiple models of photoreceptor degeneration and highlight the role that NAD+ likely plays in this process. Finally, we explore future experimental approaches to enhance our understanding of the role of NAD+ in the retina.
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Affiliation(s)
- Emily E Brown
- Ocular Genomics Institute, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Michael J Scandura
- Ocular Genomics Institute, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Eric Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear, Boston, MA, USA.
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
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Yi Z, Li S, Wang S, Xiao X, Sun W, Zhang Q. Clinical features and genetic spectrum of NMNAT1-associated retinal degeneration. Eye (Lond) 2022; 36:2279-2285. [PMID: 34837036 PMCID: PMC9674661 DOI: 10.1038/s41433-021-01853-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 10/14/2021] [Accepted: 11/10/2021] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES To systematically analyse the NMNAT1 variant spectrum and frequency, the associated phenotypic characteristics, and potential genotype-phenotype correlations based on our data and literature review. METHODS Biallelic potential pathogenic variants (PPV) in NMNAT1 were collected from our in-house exome sequencing data. Whole-genome sequencing was conducted subsequently for patients with only one heterozygous PPV detected in NMNAT1. The clinical data were reviewed and evaluated in detail. Furthermore, the literature was reviewed for reports of NMNAT1 variants and their associated phenotypes. RESULTS Eleven NMNAT1 variants, including two novel variants, were detected in 8 families from our cohort. All of the 9 available patients showed generalized tapetoretinal dystrophy at an early age (88.9% in the first decade), and disciform macular atrophy was identified in six patients from five unrelated families. Among a total of 125 patients from 8 families of our cohort and 91 families reported by the available literature, 92.9% patients showed onset of disease in the first year after birth, and 89.0% patients showed visual acuity of 0.05 or lower. All of the 39 patients with fundus photos available presented disciform macular atrophy with generalized tapetoretinal dystrophy. Most (54/80, 67.5%) of causative NMNAT1 variants were missense. The most frequent variants in Caucasian and Asian population are p.E257K and p.R237C, respectively. CONCLUSIONS Early-onset age, disciform macular atrophy with generalized tapetoretinal dystrophy, and poor visual acuity are the typical features of NMNAT1-associated retinal degeneration. Different variant hot spots of NMNAT1 were observed in different populations.
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Affiliation(s)
- Zhen Yi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Siyu Wang
- Department of Ophthalmology, Li Chuan People's Hospital, Enshi, HuBei, 445400, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, China.
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10
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Hanna J, David LA, Touahri Y, Fleming T, Screaton RA, Schuurmans C. Beyond Genetics: The Role of Metabolism in Photoreceptor Survival, Development and Repair. Front Cell Dev Biol 2022; 10:887764. [PMID: 35663397 PMCID: PMC9157592 DOI: 10.3389/fcell.2022.887764] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/19/2022] [Indexed: 12/11/2022] Open
Abstract
Vision commences in the retina with rod and cone photoreceptors that detect and convert light to electrical signals. The irreversible loss of photoreceptors due to neurodegenerative disease leads to visual impairment and blindness. Interventions now in development include transplanting photoreceptors, committed photoreceptor precursors, or retinal pigment epithelial (RPE) cells, with the latter protecting photoreceptors from dying. However, introducing exogenous human cells in a clinical setting faces both regulatory and supply chain hurdles. Recent work has shown that abnormalities in central cell metabolism pathways are an underlying feature of most neurodegenerative disorders, including those in the retina. Reversal of key metabolic alterations to drive retinal repair thus represents a novel strategy to treat vision loss based on cell regeneration. Here, we review the connection between photoreceptor degeneration and alterations in cell metabolism, along with new insights into how metabolic reprogramming drives both retinal development and repair following damage. The potential impact of metabolic reprogramming on retinal regeneration is also discussed, specifically in the context of how metabolic switches drive both retinal development and the activation of retinal glial cells known as Müller glia. Müller glia display latent regenerative properties in teleost fish, however, their capacity to regenerate new photoreceptors has been lost in mammals. Thus, re-activating the regenerative properties of Müller glia in mammals represents an exciting new area that integrates research into developmental cues, central metabolism, disease mechanisms, and glial cell biology. In addition, we discuss this work in relation to the latest insights gleaned from other tissues (brain, muscle) and regenerative species (zebrafish).
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Affiliation(s)
- Joseph Hanna
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
| | - Luke Ajay David
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
| | - Yacine Touahri
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Taylor Fleming
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
| | - Robert A. Screaton
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, Biological Sciences, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- *Correspondence: Carol Schuurmans,
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11
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Fang F, Zhuang P, Feng X, Liu P, Liu D, Huang H, Li L, Chen W, Liu L, Sun Y, Jiang H, Ye J, Hu Y. NMNAT2 is downregulated in glaucomatous RGCs, and RGC-specific gene therapy rescues neurodegeneration and visual function. Mol Ther 2022; 30:1421-1431. [PMID: 35114390 PMCID: PMC9077370 DOI: 10.1016/j.ymthe.2022.01.035] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/17/2021] [Accepted: 01/27/2022] [Indexed: 11/19/2022] Open
Abstract
The lack of neuroprotective treatments for retinal ganglion cells (RGCs) and optic nerve (ON) is a central challenge for glaucoma management. Emerging evidence suggests that redox factor NAD+ decline is a hallmark of aging and neurodegenerative diseases. Supplementation with NAD+ precursors and overexpression of NMNAT1, the key enzyme in the NAD+ biosynthetic process, have significant neuroprotective effects. We first profile the translatomes of RGCs in naive mice and mice with silicone oil-induced ocular hypertension (SOHU)/glaucoma by RiboTag mRNA sequencing. Intriguingly, only NMNAT2, but not NMNAT1 or NMNAT3, is significantly decreased in SOHU glaucomatous RGCs, which we confirm by in situ hybridization. We next demonstrate that AAV2 intravitreal injection-mediated overexpression of long half-life NMNAT2 mutant driven by RGC-specific mouse γ-synuclein (mSncg) promoter restores decreased NAD+ levels in glaucomatous RGCs and ONs. Moreover, this RGC-specific gene therapy strategy delivers significant neuroprotection of both RGC soma and axon and preservation of visual function in the traumatic ON crush model and the SOHU glaucoma model. Collectively, our studies suggest that the weakening of NMNAT2 expression in glaucomatous RGCs contributes to a deleterious NAD+ decline, and that modulating RGC-intrinsic NMNAT2 levels by AAV2-mSncg vector is a promising gene therapy for glaucomatous neurodegeneration.
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Affiliation(s)
- Fang Fang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA; Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Pei Zhuang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Xue Feng
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Pingting Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Dong Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Liang Li
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Wei Chen
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Liang Liu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Haowen Jiang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jiangbin Ye
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA.
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12
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Kayazawa T, Kuniyoshi K, Hatsukawa Y, Fujinami K, Yoshitake K, Tsunoda K, Shimojo H, Iwata T, Kusaka S. Clinical course of a Japanese girl with Leber congenital amaurosis associated with a novel nonsense pathogenic variant in NMNAT1: a case report and mini review. Ophthalmic Genet 2022; 43:400-408. [PMID: 35026968 DOI: 10.1080/13816810.2021.2023195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Leber congenital amaurosis (LCA), although rare, is one of the most severe forms of early-onset inherited retinal dystrophy (IRD). Here, we review the molecular genetics and phenotypic characteristics of patients with NMNAT1-associated IRD. The longitudinal clinical and molecular findings of a Japanese girl diagnosed with LCA associated with pathogenic variants in NMNAT1 c.648delG, (p.Trp216Ter*) and c.709C>T (p.Arg237Cys) have been described to highlight the salient clinical features of NMNAT1-associated IRD.
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Affiliation(s)
- Tomoyasu Kayazawa
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Yoshikazu Hatsukawa
- Department of Ophthalmology, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Kaoru Fujinami
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Genetics, UCL Institute of Ophthalmology Associated with Moorfields Eye Hospital, London, UK.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Kazutoshi Yoshitake
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Graduate School of Agricultural and Life Science, Faculty of Agriculture, The University of Tokyo, Tokyo, Japan
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Hiroshi Shimojo
- Department of Ophthalmology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Shunji Kusaka
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
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13
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Sokolov D, Sechrest ER, Wang Y, Nevin C, Du J, Kolandaivelu S. Nuclear NAD +-biosynthetic enzyme NMNAT1 facilitates development and early survival of retinal neurons. eLife 2021; 10:e71185. [PMID: 34878972 PMCID: PMC8754432 DOI: 10.7554/elife.71185] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Despite mounting evidence that the mammalian retina is exceptionally reliant on proper NAD+ homeostasis for health and function, the specific roles of subcellular NAD+ pools in retinal development, maintenance, and disease remain obscure. Here, we show that deletion of the nuclear-localized NAD+ synthase nicotinamide mononucleotide adenylyltransferase-1 (NMNAT1) in the developing murine retina causes early and severe degeneration of photoreceptors and select inner retinal neurons via multiple distinct cell death pathways. This severe phenotype is associated with disruptions to retinal central carbon metabolism, purine nucleotide synthesis, and amino acid pathways. Furthermore, transcriptomic and immunostaining approaches reveal dysregulation of a collection of photoreceptor and synapse-specific genes in NMNAT1 knockout retinas prior to detectable morphological or metabolic alterations. Collectively, our study reveals previously unrecognized complexity in NMNAT1-associated retinal degeneration and suggests a yet-undescribed role for NMNAT1 in gene regulation during photoreceptor terminal differentiation.
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Affiliation(s)
- David Sokolov
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
| | - Emily R Sechrest
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
- Department of Biochemistry, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
| | - Connor Nevin
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
- Department of Biochemistry, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
| | - Saravanan Kolandaivelu
- Department of Ophthalmology and Visual Sciences, Eye Institute, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
- Department of Biochemistry, One Medical Center Drive, West Virginia UniversityMorgantownUnited States
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14
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Fortunato C, Mazzola F, Raffaelli N. The key role of the NAD biosynthetic enzyme nicotinamide mononucleotide adenylyltransferase in regulating cell functions. IUBMB Life 2021; 74:562-572. [PMID: 34866305 PMCID: PMC9299865 DOI: 10.1002/iub.2584] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/09/2021] [Accepted: 11/17/2021] [Indexed: 01/06/2023]
Abstract
The enzyme nicotinamide mononucleotide adenylyltransferase (NMNAT) catalyzes a reaction central to all known NAD biosynthetic routes. In mammals, three isoforms with distinct molecular and catalytic properties, different subcellular and tissue distribution have been characterized. Each isoform is essential for cell survival, with a critical role in modulating NAD levels in a compartment‐specific manner. Each isoform supplies NAD to specific NAD‐dependent enzymes, thus regulating their activity with impact on several biological processes, including DNA repair, proteostasis, cell differentiation, and neuronal maintenance. The nuclear NMNAT1 and the cytoplasmic NMNAT2 are also emerging as relevant targets in specific types of cancers and NMNAT2 has a key role in the activation of antineoplastic compounds. This review recapitulates the biochemical properties of the three isoforms and focuses on recent advances on their protective function, involvement in human diseases and role as druggable targets.
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Affiliation(s)
- Carlo Fortunato
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Francesca Mazzola
- Department of Clinical Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Nadia Raffaelli
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
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15
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Brown EE, Scandura MJ, Mehrotra S, Wang Y, Du J, Pierce EA. Reduced nuclear NAD+ drives DNA damage and subsequent immune activation in the retina. Hum Mol Genet 2021; 31:1370-1388. [PMID: 34750622 DOI: 10.1093/hmg/ddab324] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/14/2021] [Accepted: 11/04/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in NMNAT1, a key enzyme involved in the synthesis of NAD+ in the nucleus, lead to an early onset severe inherited retinal degeneration (IRD). We aimed to understand the role of nuclear NAD+ in the retina and to identify the molecular mechanisms underlying NMNAT1-associated disease, using a mouse model that harbors the p.V9M mutation in Nmnat1 (Nmnat1V9M/V9M). We identified temporal transcriptional reprogramming in the retinas of Nmnat1V9M/V9M mice prior to retinal degeneration, which begins at 4 weeks of age, with no significant alterations in gene expression at 2 weeks of age and over 2600 differentially expressed genes by 3 weeks of age. Expression of the primary consumer of NAD+ in the nucleus, PARP1, an enzyme involved in DNA damage repair and transcriptional regulation, as well as 7 other PARP family enzymes, was elevated in the retinas of Nmnat1V9M/V9M. This was associated with elevated levels of DNA damage, PARP-mediated NAD+ consumption, and migration of Iba1+/CD45+ microglia/macrophages to the subretinal space in the retinas of Nmnat1V9M/V9M mice. These findings suggest that photoreceptor cells are especially sensitive to perturbation of genome homeostasis, and that PARP-mediated cell death may play a role in other genetic forms of IRDs, and potentially other forms of neurodegeneration.
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Affiliation(s)
- Emily E Brown
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
| | - Michael J Scandura
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
| | - Sudeep Mehrotra
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, 26506, USA.,Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV, 26506, USA.,Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, 02114, USA
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16
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Bedoni N, Quinodoz M, Pinelli M, Cappuccio G, Torella A, Nigro V, Testa F, Simonelli F, Corton M, Lualdi S, Lanza F, Morana G, Ayuso C, Di Rocco M, Filocamo M, Banfi S, Brunetti-Pierri N, Superti-Furga A, Rivolta C. An Alu-mediated duplication in NMNAT1, involved in NAD biosynthesis, causes a novel syndrome, SHILCA, affecting multiple tissues and organs. Hum Mol Genet 2021; 29:2250-2260. [PMID: 32533184 DOI: 10.1093/hmg/ddaa112] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/30/2020] [Accepted: 06/01/2020] [Indexed: 12/22/2022] Open
Abstract
We investigated the genetic origin of the phenotype displayed by three children from two unrelated Italian families, presenting with a previously unrecognized autosomal recessive disorder that included a severe form of spondylo-epiphyseal dysplasia, sensorineural hearing loss, intellectual disability and Leber congenital amaurosis (SHILCA), as well as some brain anomalies that were visible at the MRI. Autozygome-based analysis showed that these children shared a 4.76 Mb region of homozygosity on chromosome 1, with an identical haplotype. Nonetheless, whole-exome sequencing failed to identify any shared rare coding variants, in this region or elsewhere. We then determined the transcriptome of patients' fibroblasts by RNA sequencing, followed by additional whole-genome sequencing experiments. Gene expression analysis revealed a 4-fold downregulation of the gene NMNAT1, residing indeed in the shared autozygous interval. Short- and long-read whole-genome sequencing highlighted a duplication involving 2 out of the 5 exons of NMNAT1 main isoform (NM_022787.3), leading to the production of aberrant mRNAs. Pathogenic variants in NMNAT1 have been previously shown to cause non-syndromic Leber congenital amaurosis (LCA). However, no patient with null biallelic mutations has ever been described, and murine Nmnat1 knockouts show embryonic lethality, indicating that complete absence of NMNAT1 activity is probably not compatible with life. The rearrangement found in our cases, presumably causing a strong but not complete reduction of enzymatic activity, may therefore result in an intermediate syndromic phenotype with respect to LCA and lethality.
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Affiliation(s)
- Nicola Bedoni
- Department of Computational Biology, University of Lausanne, 1011 Lausanne, Switzerland.,Division of Genetic Medicine, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Mathieu Quinodoz
- Department of Computational Biology, University of Lausanne, 1011 Lausanne, Switzerland.,Department of Genetics and Genome Biology, University of LE1 7RH Leicester, Leicester, UK.,Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland.,Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Department of Translational Medicine, Section of Pediatrics, Federico II University, 80131 Naples, Italy
| | - Gerarda Cappuccio
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Department of Translational Medicine, Section of Pediatrics, Federico II University, 80131 Naples, Italy
| | - Annalaura Torella
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Medical Genetics, Department of Precision Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Medical Genetics, Department of Precision Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", 80131 Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania "Luigi Vanvitelli", 80131 Naples, Italy
| | | | - Marta Corton
- Department of Genetics, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz, University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, 28029 Madrid, Spain
| | - Susanna Lualdi
- Laboratorio di Genetica Molecolare e Biobanche, Istituto G. Gaslini, 16147 Genoa, Italy
| | - Federica Lanza
- Laboratorio di Genetica Molecolare e Biobanche, Istituto G. Gaslini, 16147 Genoa, Italy
| | - Giovanni Morana
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Carmen Ayuso
- Department of Genetics, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz, University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, 28029 Madrid, Spain
| | - Maja Di Rocco
- Laboratorio di Genetica Molecolare e Biobanche, Istituto G. Gaslini, 16147 Genoa, Italy
| | - Mirella Filocamo
- Laboratorio di Genetica Molecolare e Biobanche, Istituto G. Gaslini, 16147 Genoa, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Medical Genetics, Department of Precision Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Department of Translational Medicine, Section of Pediatrics, Federico II University, 80131 Naples, Italy
| | - Andrea Superti-Furga
- Division of Genetic Medicine, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Carlo Rivolta
- Department of Genetics and Genome Biology, University of LE1 7RH Leicester, Leicester, UK.,Institute of Molecular and Clinical Ophthalmology Basel, 4031 Basel, Switzerland.,Department of Ophthalmology, University of Basel, 4031 Basel, Switzerland
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17
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Meunier I, Bocquet B, Charif M, Dhaenens CM, Manes G, Amati-Bonneau P, Roubertie A, Zanlonghi X, Lenaers G. A ROD-CONE DYSTROPHY IS SYSTEMATICALLY ASSOCIATED TO THE RTN4IP1 RECESSIVE OPTIC ATROPHY. Retina 2021; 41:1771-1779. [PMID: 33315831 PMCID: PMC8297537 DOI: 10.1097/iae.0000000000003054] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE RTN4IP1 biallelic mutations cause a recessive optic atrophy, sometimes associated to more severe neurological syndromes, but so far, no retinal phenotype has been reported in RTN4IP1 patients, justifying their reappraisal. METHODS Seven patients from four families carrying biallelic RTN4IP1 variants were retrospectively reviewed, with emphasis on their age of onset, visual acuity, multimodal imaging including color and autofluorescence frames, spectral-domain optical coherence tomography with RNFL and macular analyses. RESULTS Seven patients from four RTN4IP1 families developed in their first decade of life a bilateral recessive optic atrophy with severe central visual loss, and primary nystagmus developed in 5 of 7 patients. Six patients were legally blind. In a second stage, the seven individuals developed a rod-cone dystrophy, sparing the macular zone and the far periphery. This retinal damage was identified by 55° field fundus autofluorescence frames and also by spectral-domain optical coherence tomography scans of the temporal part of the macular zone in five of the seven patients. Full-field electroretinography measurements disclosed reduced b-wave amplitude of the rod responses in all patients but two. Family 4 with the p.R103H and c.601A > T (p.K201*) truncating mutation had further combined neurological signs with cerebellar ataxia, seizures, and intellectual disability. CONCLUSION RTN4IP1 recessive optic atrophy is systematically associated to a rod-cone dystrophy, which suggests that both the retinal ganglion cells and the rods are affected as a result of a deficit in the mitochondrial respiratory chain. Thus, systematic widefield autofluorescence frames and temporal macular scans are recommended for the evaluation of patients with optic neuropathies.
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Affiliation(s)
- Isabelle Meunier
- Institute for Neurosciences of Montpellier U1051, University of Montpellier, Montpellier, France
- National Center in Rare Diseases, Genetics of Sensory Diseases, University Hospital, Montpellier, France
| | - Béatrice Bocquet
- Institute for Neurosciences of Montpellier U1051, University of Montpellier, Montpellier, France
- National Center in Rare Diseases, Genetics of Sensory Diseases, University Hospital, Montpellier, France
| | - Majida Charif
- Genetics, and Immuno-cell Therapy Team, Mohammed First University, Oujda, Morocco
| | - Claire-Marie Dhaenens
- Biochemistry and Molecular Biology Department—UF Génopathies, Univ Lille, Lille, France
| | - Gael Manes
- Institute for Neurosciences of Montpellier U1051, University of Montpellier, Montpellier, France
| | | | - Agathe Roubertie
- Institute for Neurosciences of Montpellier U1051, University of Montpellier, Montpellier, France
- National Center in Rare Diseases, Genetics of Sensory Diseases, University Hospital, Montpellier, France
| | | | - Guy Lenaers
- MitoLab Team, UMR CNRS 6015—INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
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18
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Zapata‐Pérez R, Wanders RJA, van Karnebeek CDM, Houtkooper RH. NAD + homeostasis in human health and disease. EMBO Mol Med 2021; 13:e13943. [PMID: 34041853 PMCID: PMC8261484 DOI: 10.15252/emmm.202113943] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/15/2021] [Accepted: 03/25/2021] [Indexed: 12/12/2022] Open
Abstract
Depletion of nicotinamide adenine dinucleotide (NAD+ ), a central redox cofactor and the substrate of key metabolic enzymes, is the causative factor of a number of inherited and acquired diseases in humans. Primary deficiencies of NAD+ homeostasis are the result of impaired biosynthesis, while secondary deficiencies can arise due to other factors affecting NAD+ homeostasis, such as increased NAD+ consumption or dietary deficiency of its vitamin B3 precursors. NAD+ depletion can manifest in a wide variety of pathological phenotypes, ranging from rare inherited defects, characterized by congenital malformations, retinal degeneration, and/or encephalopathy, to more common multifactorial, often age-related, diseases. Here, we discuss NAD+ biochemistry and metabolism and provide an overview of the etiology and pathological consequences of alterations of the NAD+ metabolism in humans. Finally, we discuss the state of the art of the potential therapeutic implications of NAD+ repletion for boosting health as well as treating rare and common diseases, and the possibilities to achieve this by means of the different NAD+ -enhancing agents.
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Affiliation(s)
- Rubén Zapata‐Pérez
- Laboratory Genetic Metabolic DiseasesAmsterdam Gastroenterology, Endocrinology, and Metabolism (AGEM)Amsterdam Cardiovascular Sciences (ACS)Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic DiseasesAmsterdam Gastroenterology, Endocrinology, and Metabolism (AGEM)Amsterdam Cardiovascular Sciences (ACS)Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
| | - Clara D M van Karnebeek
- Department of PediatricsAmsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
- Department of Pediatrics (Metabolic Diseases)Radboud Centre for Mitochondrial MedicineAmalia Children’s HospitalRadboud University Medical CenterNijmegenThe Netherlands
- On behalf of ‘United for Metabolic Diseases’AmsterdamThe Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic DiseasesAmsterdam Gastroenterology, Endocrinology, and Metabolism (AGEM)Amsterdam Cardiovascular Sciences (ACS)Amsterdam UMCUniversity of AmsterdamAmsterdamThe Netherlands
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19
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Greenwald SH, Brown EE, Scandura MJ, Hennessey E, Farmer R, Du J, Wang Y, Pierce EA. Mutant Nmnat1 leads to a retina-specific decrease of NAD+ accompanied by increased poly(ADP-ribose) in a mouse model of NMNAT1-associated retinal degeneration. Hum Mol Genet 2021; 30:644-657. [PMID: 33709122 PMCID: PMC8127407 DOI: 10.1093/hmg/ddab070] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/01/2021] [Accepted: 03/04/2021] [Indexed: 12/11/2022] Open
Abstract
Nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) is required for nuclear nicotinamide adenine mononucleotide (NAD+) biosynthesis in all nucleated cells, and despite its functional ubiquity, mutations in this gene lead to an isolated retinal degeneration. The mechanisms underlying how mutant NMNAT1 causes disease are not well understood, nor is the reason why the pathology is confined to the retina. Using a mouse model of NMNAT1-associated retinal degeneration that harbors the p.Val9Met mutation, we tested the hypothesis that decreased function of mutant NMNAT1 has a greater effect on the levels of NAD+ in the retina than elsewhere in the body. Measurements by liquid chromatography with tandem mass spectrometry showed an early and sustained decrease of NAD+ in mutant retinas that was not observed in other tissues. To understand how consumers of nuclear NAD+ are affected by the reduced availability of NAD+ in mutant retinas, poly(ADP-ribose) polymerase (PARP) and nuclear sirtuin activity were evaluated. PARP activity was elevated during disease progression, as evidenced by overproduction of poly(ADP-ribose) (PAR) in photoreceptors, whereas histone deacetylation activity of nuclear sirtuins was not altered. We hypothesized that PARP could be activated because of elevated levels of oxidative stress; however, we did not observe oxidative DNA damage, lipid peroxidation, or a low glutathione to oxidized glutathione ratio. Terminal deoxynucleotidyl transferase dUTP nick end labeling staining revealed that photoreceptors appear to ultimately die by apoptosis, although the low NAD+ levels and overproduction of PAR suggest that cell death may include aspects of the parthanatos cell death pathway.
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Affiliation(s)
- Scott H Greenwald
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Emily E Brown
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Michael J Scandura
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Erin Hennessey
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Raymond Farmer
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506, USA
- Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV 26506, USA
- Department of Biochemistry, West Virginia University, Morgantown, WV 26506, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
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20
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Hopp AK, Hottiger MO. Uncovering the Invisible: Mono-ADP-ribosylation Moved into the Spotlight. Cells 2021; 10:680. [PMID: 33808662 PMCID: PMC8003356 DOI: 10.3390/cells10030680] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 02/06/2023] Open
Abstract
Adenosine diphosphate (ADP)-ribosylation is a nicotinamide adenine dinucleotide (NAD+)-dependent post-translational modification that is found on proteins as well as on nucleic acids. While ARTD1/PARP1-mediated poly-ADP-ribosylation has extensively been studied in the past 60 years, comparably little is known about the physiological function of mono-ADP-ribosylation and the enzymes involved in its turnover. Promising technological advances have enabled the development of innovative tools to detect NAD+ and NAD+/NADH (H for hydrogen) ratios as well as ADP-ribosylation. These tools have significantly enhanced our current understanding of how intracellular NAD dynamics contribute to the regulation of ADP-ribosylation as well as to how mono-ADP-ribosylation integrates into various cellular processes. Here, we discuss the recent technological advances, as well as associated new biological findings and concepts.
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Affiliation(s)
| | - Michael O. Hottiger
- Department of Molecular Mechanisms of Disease (DMMD), University of Zurich, 8057 Zurich, Switzerland;
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21
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Neuroprotective effects and mechanisms of action of nicotinamide mononucleotide (NMN) in a photoreceptor degenerative model of retinal detachment. Aging (Albany NY) 2020; 12:24504-24521. [PMID: 33373320 PMCID: PMC7803565 DOI: 10.18632/aging.202453] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/21/2020] [Indexed: 01/17/2023]
Abstract
Currently, no pharmacotherapy has been proven effective in treating photoreceptor degeneration in patients. Discovering readily available and safe neuroprotectants is therefore highly sought after. Here, we investigated nicotinamide mononucleotide (NMN), a precursor of nicotinamide adenine dinucleotide (NAD+), in a retinal detachment (RD) induced photoreceptor degeneration. NMN administration after RD resulted in a significant reduction of TUNEL+ photoreceptors, CD11b+ macrophages, and GFAP labeled glial activation; a normalization of protein carbonyl content (PCC), and a preservation of the outer nuclear layer (ONL) thickness. NMN administration significantly increased NAD+ levels, SIRT1 protein expression, and heme oxygenase-1 (HO-1) expression. Delayed NMN administration still exerted protective effects after RD. Mechanistic in vitro studies using 661W cells revealed a SIRT1/HO-1 signaling as a downstream effector of NMN-mediated protection under oxidative stress and LPS stimulation. In conclusion, NMN administration exerts neuroprotective effects on photoreceptors after RD and oxidative injury, suggesting a therapeutic avenue to treating photoreceptor degeneration.
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22
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Skorczyk-Werner A, Niedziela Z, Stopa M, Krawczyński MR. Novel gene variants in Polish patients with Leber congenital amaurosis (LCA). Orphanet J Rare Dis 2020; 15:345. [PMID: 33308271 PMCID: PMC7731562 DOI: 10.1186/s13023-020-01634-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/27/2020] [Indexed: 12/26/2022] Open
Abstract
Background Leber congenital amaurosis (LCA) is a rare retinal disease that is the most frequent cause of congenital blindness in children and the most severe form of inherited retinal dystrophies. To date, 25 genes have been implicated in the pathogenesis of LCA. As gene therapy is becoming available, the identification of potential treatment candidates is crucial. The aim of the study was to report the molecular basis of Leber congenital amaurosis in 22 Polish families.
Methods Single Nucleotide Polymorphism-microarray for LCA genes or Next Generation Sequencing diagnostic panel for LCA genes (or both tests) were performed to identify potentially pathogenic variants. Bidirectional Sanger sequencing was carried out for validation and segregation analysis of the variants identified within the families. Results The molecular background was established in 22 families. From a total of 24 identified variants, 23 were predicted to affect protein-coding or splicing, including 10 novel variants. The variants were identified in 7 genes: CEP290, GUCY2D, RPE65, NMNAT1, CRB1, RPGRIP1, and CRX. More than one-third of the patients, with clinical LCA diagnosis confirmed by the results of molecular analysis, appeared to be affected with a severe form of the disease: LCA10 caused by the CEP290 gene variants. Intronic mutation c.2991+1655A>G in the CEP290 gene was the most frequent variant identified in the studied group. Conclusions This study provides the first molecular genetic characteristics of patients with Leber congenital amaurosis from the previously unexplored Polish population. Our study expands the mutational spectrum as we report 10 novel variants identified in LCA genes. The fact that the most frequent causes of the disease in the studied group of Polish patients are mutations in one out of three genes that are currently the targets for gene therapy (CEP290, GUCY2D, and RPE65) strongly emphasizes the importance of the molecular background analyses of LCA in Polish patients.
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Affiliation(s)
- Anna Skorczyk-Werner
- Department of Medical Genetics, Poznan University of Medical Sciences, 8, Rokietnicka St, 60-806, Poznan, Poland.
| | - Zuzanna Niedziela
- Department of Medical Genetics, Poznan University of Medical Sciences, 8, Rokietnicka St, 60-806, Poznan, Poland.,Department of Ophthalmology, Chair of Ophthalmology and Optometry, Poznan University of Medical Sciences, Poznan, Poland
| | - Marcin Stopa
- Department of Ophthalmology, Chair of Ophthalmology and Optometry, Poznan University of Medical Sciences, Poznan, Poland
| | - Maciej Robert Krawczyński
- Department of Medical Genetics, Poznan University of Medical Sciences, 8, Rokietnicka St, 60-806, Poznan, Poland.,Centers for Medical Genetics GENESIS, Poznan, Poland
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23
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Sasaki Y, Kakita H, Kubota S, Sene A, Lee TJ, Ban N, Dong Z, Lin JB, Boye SL, DiAntonio A, Boye SE, Apte RS, Milbrandt J. SARM1 depletion rescues NMNAT1-dependent photoreceptor cell death and retinal degeneration. eLife 2020; 9:e62027. [PMID: 33107823 PMCID: PMC7591247 DOI: 10.7554/elife.62027] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/13/2020] [Indexed: 01/02/2023] Open
Abstract
Leber congenital amaurosis type nine is an autosomal recessive retinopathy caused by mutations of the NAD+ synthesis enzyme NMNAT1. Despite the ubiquitous expression of NMNAT1, patients do not manifest pathologies other than retinal degeneration. Here we demonstrate that widespread NMNAT1 depletion in adult mice mirrors the human pathology, with selective loss of photoreceptors highlighting the exquisite vulnerability of these cells to NMNAT1 loss. Conditional deletion demonstrates that NMNAT1 is required within the photoreceptor. Mechanistically, loss of NMNAT1 activates the NADase SARM1, the central executioner of axon degeneration, to trigger photoreceptor death and vision loss. Hence, the essential function of NMNAT1 in photoreceptors is to inhibit SARM1, highlighting an unexpected shared mechanism between axonal degeneration and photoreceptor neurodegeneration. These results define a novel SARM1-dependent photoreceptor cell death pathway and identifies SARM1 as a therapeutic candidate for retinopathies.
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Affiliation(s)
- Yo Sasaki
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
| | - Hiroki Kakita
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
- Department of Perinatal and Neonatal Medicine, Aichi Medical UniversityAichiJapan
| | - Shunsuke Kubota
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Abdoulaye Sene
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Tae Jun Lee
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Norimitsu Ban
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Zhenyu Dong
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Joseph B Lin
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Sanford L Boye
- Department of Pediatrics, Powell Gene Therapy CenterGainesvilleUnited States
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Needleman Center for Neurometabolism and Axonal TherapeuticsSt. LouisUnited States
| | - Shannon E Boye
- Department of Pediatrics, Division of Cellular and Molecular TherapyGainesvilleUnited States
| | - Rajendra S Apte
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Department of Medicine, Washington University School of MedicineSt. LouisUnited States
| | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
- Needleman Center for Neurometabolism and Axonal TherapeuticsSt. LouisUnited States
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24
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Sallum JMF, Motta FL, Arno G, Porto FBO, Resende RG, Belfort R. Clinical and molecular findings in a cohort of 152 Brazilian severe early onset inherited retinal dystrophy patients. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:728-752. [PMID: 32865313 DOI: 10.1002/ajmg.c.31828] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/25/2020] [Accepted: 07/28/2020] [Indexed: 12/17/2022]
Abstract
Leber congenital amaurosis (LCA) and early-onset retinal dystrophy (EORD) are severe inherited retinal dystrophy that can cause deep blindness childhood. They represent 5% of all retinal dystrophies in the world population and about 10% in Brazil. Clinical findings and molecular basis of syndromic and nonsyndromic LCA/EORD in a Brazilian sample (152 patients/137 families) were studied. In this population, 15 genes were found to be related to the phenotype, 38 new variants were detected and four new complex alleles were discovered. Among 123 variants found, the most common were CEP290: c.2991+1655A>G, CRB1: p.Cys948Tyr, and RPGRIP1: exon10-18 deletion.
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Affiliation(s)
- Juliana Maria Ferraz Sallum
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil.,Instituto de Genética Ocular, Sao Paulo, Brazil
| | - Fabiana Louise Motta
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil.,Instituto de Genética Ocular, Sao Paulo, Brazil
| | - Gavin Arno
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Fernanda Belga Ottoni Porto
- INRET Clínica e Centro de Pesquisa, Belo Horizonte, Minas Gerais, Brazil.,Centro Oftalmológico de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Rubens Belfort
- Department of Ophthalmology, Universidade Federal de São Paulo, Sao Paulo, Brazil
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25
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Greenwald SH, Brown EE, Scandura MJ, Hennessey E, Farmer R, Pawlyk BS, Xiao R, Vandenberghe LH, Pierce EA. Gene Therapy Preserves Retinal Structure and Function in a Mouse Model of NMNAT1-Associated Retinal Degeneration. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 18:582-594. [PMID: 32775493 PMCID: PMC7397406 DOI: 10.1016/j.omtm.2020.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022]
Abstract
No treatment is available for nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1)-associated retinal degeneration, an inherited disease that leads to severe vision loss early in life. Although the causative gene, NMNAT1, plays an essential role in nuclear nicotinamide adenine dinucleotide (NAD)+ metabolism in tissues throughout the body, NMNAT1-associated disease is isolated to the retina. Since this condition is recessive, supplementing the retina with a normal copy of NMNAT1 should protect vulnerable cells from disease progression. We tested this hypothesis in a mouse model that harbors the p.Val9Met mutation in Nmnat1 and consequently develops a retinal degenerative phenotype that recapitulates key features of the human disease. Gene augmentation therapy, delivered by subretinal injection of adeno-associated virus (AAV) carrying a normal human copy of NMNAT1, rescued retinal structure and function. Due to the early-onset profile of the phenotype, a rapidly activating self-complementary AAV was required to initiate transgene expression during the narrow therapeutic window. These data represent the first proof of concept for a therapy to treat patients with NMNAT1-associated disease.
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Affiliation(s)
- Scott H Greenwald
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Emily E Brown
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Michael J Scandura
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Erin Hennessey
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Raymond Farmer
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Basil S Pawlyk
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Ru Xiao
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Ocular Genomics Institute, Grousebeck Gene Therapy Center, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Luk H Vandenberghe
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Ocular Genomics Institute, Grousebeck Gene Therapy Center, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
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26
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Abstract
We report the molecular basis of the largest Tunisian cohort with inherited retinal dystrophies (IRD) reported to date, identify disease-causing pathogenic variants and describe genotype-phenotype correlations. A subset of 26 families from a cohort of 73 families with clinical diagnosis of autosomal recessive IRD (AR-IRD) excluding Usher syndrome was analyzed by whole exome sequencing and autozygosity mapping. Causative pathogenic variants were identified in 50 families (68.4%), 42% of which were novel. The most prevalent pathogenic variants were observed in ABCA4 (14%) and RPE65, CRB1 and CERKL (8% each). 26 variants (8 novel and 18 known) in 19 genes were identified in 26 families (14 missense substitutions, 5 deletions, 4 nonsense pathogenic variants and 3 splice site variants), with further allelic heterogeneity arising from different pathogenic variants in the same gene. The most common phenotype in our cohort is retinitis pigmentosa (23%) and cone rod dystrophy (23%) followed by Leber congenital amaurosis (19.2%). We report the association of new disease phenotypes. This research was carried out in Tunisian patients with IRD in order to delineate the genetic population architecture.
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27
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Cambronne XA, Kraus WL. Location, Location, Location: Compartmentalization of NAD + Synthesis and Functions in Mammalian Cells. Trends Biochem Sci 2020; 45:858-873. [PMID: 32595066 DOI: 10.1016/j.tibs.2020.05.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 05/06/2020] [Accepted: 05/19/2020] [Indexed: 02/07/2023]
Abstract
The numerous biological roles of NAD+ are organized and coordinated via its compartmentalization within cells. The spatial and temporal partitioning of this intermediary metabolite is intrinsic to understanding the impact of NAD+ on cellular signaling and metabolism. We review evidence supporting the compartmentalization of steady-state NAD+ levels in cells, as well as how the modulation of NAD+ synthesis dynamically regulates signaling by controlling subcellular NAD+ concentrations. We further discuss potential benefits to the cell of compartmentalizing NAD+, and methods for measuring subcellular NAD+ levels.
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Affiliation(s)
- Xiaolu A Cambronne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
| | - W Lee Kraus
- Laboratory of Signaling and Gene Regulation, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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28
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NMNAT1-ASSOCIATED CONE-ROD DYSTROPHY: EVIDENCE FOR A SPECTRUM OF FOVEAL MALDEVELOPMENT. Retin Cases Brief Rep 2020; 16:385-392. [PMID: 32150116 DOI: 10.1097/icb.0000000000000992] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe in detail the phenotype of two siblings with biallelic NMNAT1 mutations. METHODS A 4-year-old male patient (P1) and his 7-year-old sister (P2), product of a nonconsanguineous union of Egyptian ancestry, underwent a comprehensive ophthalmic examination, retinal imaging with spectral domain optical coherence tomography and near infrared (NIR) fundus autofluorescence (FAF), and full-field electroretinograms (ERG). RESULTS Patients had blurred vision and nystagmus at ∼3 years of age. P2 was hyperopic (+6D). Visual acuity in P1 was 20/100 at age 3 and remained at ∼20/125 at age 4; P2 visual acuity was 20/70 at age 4 and declined to ∼20/200 at age 7. ERGs recorded in P1 showed relatively large rod-mediated responses but nearly undetectable cone signals. There was foveal/parafoveal depigmentation. Spectral domain optical coherence tomography showed hypoplastic foveas, a thin outer nuclear layer centrally but normal thickness beyond the vascular arcades. At the foveal center, cone outer segments were absent and the outer nuclear layer was further hyporreflective. The inner retina was mostly within normal limits. There was central depigmentation on near infrared fundus autofluorescence. Biallelic mutations were identified in NMNAT1: One was previously reported (c.769 G>A; pGlu257Lys), and the other one (c.245T>C; pVal82Ala) was novel. CONCLUSION NMNAT1 mutations cause a consistent phenotype characterized by early-onset, progressive, cone>rod retinawide dysfunction and predominantly central abnormalities ranging from a hypoplastic to an atrophic fovea, supporting a critical role for NMNAT1 in central retinal development and maintenance. Relatively preserved inner retina and detectable photoreceptors may become therapeutic targets.
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29
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Croft T, Venkatakrishnan P, Lin SJ. NAD + Metabolism and Regulation: Lessons From Yeast. Biomolecules 2020; 10:E330. [PMID: 32092906 PMCID: PMC7072712 DOI: 10.3390/biom10020330] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/15/2020] [Accepted: 02/16/2020] [Indexed: 12/13/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite involved in various cellular processes. The cellular NAD+ pool is maintained by three biosynthesis pathways, which are largely conserved from bacteria to human. NAD+ metabolism is an emerging therapeutic target for several human disorders including diabetes, cancer, and neuron degeneration. Factors regulating NAD+ homeostasis have remained incompletely understood due to the dynamic nature and complexity of NAD+ metabolism. Recent studies using the genetically tractable budding yeast Saccharomyces cerevisiae have identified novel NAD+ homeostasis factors. These findings help provide a molecular basis for how may NAD+ and NAD+ homeostasis factors contribute to the maintenance and regulation of cellular function. Here we summarize major NAD+ biosynthesis pathways, selected cellular processes that closely connect with and contribute to NAD+ homeostasis, and regulation of NAD+ metabolism by nutrient-sensing signaling pathways. We also extend the discussions to include possible implications of NAD+ homeostasis factors in human disorders. Understanding the cross-regulation and interconnections of NAD+ precursors and associated cellular pathways will help elucidate the mechanisms of the complex regulation of NAD+ homeostasis. These studies may also contribute to the development of effective NAD+-based therapeutic strategies specific for different types of NAD+ deficiency related disorders.
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Affiliation(s)
| | | | - Su-Ju Lin
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California, Davis, CA 95616, USA; (T.C.); (P.V.)
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30
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Ritter M, Arno G, Ba-Abbad R, Holder GE, Webster AR. Macular maldevelopment in ATF6-mediated retinal dysfunction. Ophthalmic Genet 2020; 40:564-569. [PMID: 31900015 DOI: 10.1080/13816810.2019.1706749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background: Achromatopsia has been previously associated with mutations in the ATF6 gene. Rod-monochromatism, foveal hypoplasia, and disruption of the subfoveal photoreceptor layer are described as phenotypical features. We report detailed structural and electrophysiological assessment of two patients from two families, one manifesting severe macular maldevelopment and one with foveal hypoplasia.Materials and methods: The patients underwent a complete ophthalmic examination including electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence, and fundus photography. Genetic testing was performed by next-generation sequencing.Results: In one patient, fundoscopy and SD-OCT revealed well-demarcated coloboma-like excavated lesions at the central macula of both eyes. Genetic analysis identified a novel homozygous p.Asp140Ter mutation in the ATF6 gene. The second patient had foveal hypoplasia in association with a homozygous ATF6 mutation affecting a splice donor site (c.1187 + 5G>C). In both patients, electrophysiological assessment showed normal rod-specific (DA 0.01) and dark-adapted bright white-flash ERGs (DA 10.0). 30 Hz flicker ERGs were undetectable. There were low-amplitude single-flash photopic ERGs (LA 3.0) with timing and shape suggesting S-cone origin.Conclusions: The findings, particularly a case with severe macular maldevelopment, may expand on the phenotype previously associated with ATF6-mediated achromatopsia. In addition, the comprehensive electrophysiological assessment suggests that preserved S-cone activity can be detected in this particular molecular sub-type of cone dysfunction.
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Affiliation(s)
- Markus Ritter
- Moorfields Eye Hospital, London, UK.,Department of Ophthalmology, Medical University of Vienna, Vienna, Austria
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Rola Ba-Abbad
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
| | - Graham E Holder
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK.,National University of Singapore, Department of Ophthalmology, National University Hospital, Singapore
| | - Andrew R Webster
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
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31
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Ma X, Zhu Y, Lu J, Xie J, Li C, Shin WS, Qiang J, Liu J, Dou S, Xiao Y, Wang C, Jia C, Long H, Yang J, Fang Y, Jiang L, Zhang Y, Zhang S, Zhai RG, Liu C, Li D. Nicotinamide mononucleotide adenylyltransferase uses its NAD + substrate-binding site to chaperone phosphorylated Tau. eLife 2020; 9:51859. [PMID: 32250733 PMCID: PMC7136026 DOI: 10.7554/elife.51859] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 03/21/2020] [Indexed: 01/07/2023] Open
Abstract
Tau hyper-phosphorylation and deposition into neurofibrillary tangles have been found in brains of patients with Alzheimer's disease (AD) and other tauopathies. Molecular chaperones are involved in regulating the pathological aggregation of phosphorylated Tau (pTau) and modulating disease progression. Here, we report that nicotinamide mononucleotide adenylyltransferase (NMNAT), a well-known NAD+ synthase, serves as a chaperone of pTau to prevent its amyloid aggregation in vitro as well as mitigate its pathology in a fly tauopathy model. By combining NMR spectroscopy, crystallography, single-molecule and computational approaches, we revealed that NMNAT adopts its enzymatic pocket to specifically bind the phosphorylated sites of pTau, which can be competitively disrupted by the enzymatic substrates of NMNAT. Moreover, we found that NMNAT serves as a co-chaperone of Hsp90 for the specific recognition of pTau over Tau. Our work uncovers a dedicated chaperone of pTau and suggests NMNAT as a key node between NAD+ metabolism and Tau homeostasis in aging and neurodegeneration.
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Affiliation(s)
- Xiaojuan Ma
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of the Chinese Academy of SciencesBeijingChina
| | - Yi Zhu
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of MedicineMiamiUnited States
| | - Jinxia Lu
- Bio-X-Renji Hospital Research Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong UniversityShanghaiChina,Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong UniversityShanghaiChina
| | - Jingfei Xie
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of the Chinese Academy of SciencesBeijingChina
| | - Chong Li
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of MedicineMiamiUnited States
| | - Woo Shik Shin
- Department of Neurology, Molecular Biology Institute, and Brain Research Institute, University of California, Los AngelesLos AngelesUnited States
| | - Jiali Qiang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of the Chinese Academy of SciencesBeijingChina
| | - Jiaqi Liu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai UniversityYantaiChina
| | - Shuai Dou
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Yi Xiao
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Chuchu Wang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of the Chinese Academy of SciencesBeijingChina
| | - Chunyu Jia
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of the Chinese Academy of SciencesBeijingChina
| | - Houfang Long
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina,University of the Chinese Academy of SciencesBeijingChina
| | - Juntao Yang
- State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical CollegeBeijingChina
| | - Yanshan Fang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Lin Jiang
- Department of Neurology, Molecular Biology Institute, and Brain Research Institute, University of California, Los AngelesLos AngelesUnited States
| | - Yaoyang Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Shengnan Zhang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Rong Grace Zhai
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of MedicineMiamiUnited States
| | - Cong Liu
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of SciencesShanghaiChina
| | - Dan Li
- Bio-X-Renji Hospital Research Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong UniversityShanghaiChina,Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong UniversityShanghaiChina
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32
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Hikosaka K, Yaku K, Okabe K, Nakagawa T. Implications of NAD metabolism in pathophysiology and therapeutics for neurodegenerative diseases. Nutr Neurosci 2019; 24:371-383. [PMID: 31280708 DOI: 10.1080/1028415x.2019.1637504] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme that mediates various redox reactions. Particularly, mitochondrial NAD plays a critical role in energy production pathways, including the tricarboxylic acid (TCA) cycle, fatty acid oxidation, and oxidative phosphorylation. NAD also serves as a substrate for ADP-ribosylation and deacetylation by poly(ADP-ribose) polymerases (PARPs) and sirtuins, respectively. Thus, NAD regulates energy metabolism, DNA damage repair, gene expression, and stress response. Numerous studies have demonstrated the involvement of NAD metabolism in neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and retinal degenerative diseases. Mitochondrial dysfunction is considered crucial pathogenesis for neurodegenerative diseases such as AD and PD. Maintaining appropriate NAD levels is important for mitochondrial function. Indeed, decreased NAD levels are observed in AD and PD, and supplementation of NAD precursors ameliorates disease phenotypes by activating mitochondrial functions. NAD metabolism also plays an important role in axonal degeneration, a characteristic feature of peripheral neuropathy and neurodegenerative diseases. In addition, dysregulated NAD metabolism is implicated in retinal degenerative diseases such as glaucoma and Leber congenital amaurosis, and NAD metabolism is considered a therapeutic target for these diseases. In this review, we summarize the involvement of NAD metabolism in axon degeneration and various neurodegenerative diseases and discuss perspectives of nutritional intervention using NAD precursors.
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Affiliation(s)
- Keisuke Hikosaka
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
| | - Keisuke Yaku
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
| | - Keisuke Okabe
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan.,First Department of Internal Medicine, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan
| | - Takashi Nakagawa
- Department of Metabolism and Nutrition, Graduate School of Medicine and Pharmaceutical Science for Research, University of Toyama, Toyama, Japan.,Institute of Natural Medicine, University of Toyama, Toyama, Japan
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Lukacs M, Gilley J, Zhu Y, Orsomando G, Angeletti C, Liu J, Yang X, Park J, Hopkin RJ, Coleman MP, Zhai RG, Stottmann RW. Severe biallelic loss-of-function mutations in nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) in two fetuses with fetal akinesia deformation sequence. Exp Neurol 2019; 320:112961. [PMID: 31136762 DOI: 10.1016/j.expneurol.2019.112961] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/14/2019] [Accepted: 05/17/2019] [Indexed: 10/26/2022]
Abstract
The three nicotinamide mononucleotide adenylyltransferase (NMNAT) family members synthesize the electron carrier nicotinamide adenine dinucleotide (NAD+) and are essential for cellular metabolism. In mammalian axons, NMNAT activity appears to be required for axon survival and is predominantly provided by NMNAT2. NMNAT2 has recently been shown to also function as a chaperone to aid in the refolding of misfolded proteins. Nmnat2 deficiency in mice, or in its ortholog dNmnat in Drosophila, results in axon outgrowth and survival defects. Peripheral nerve axons in NMNAT2-deficient mice fail to extend and innervate targets, and skeletal muscle is severely underdeveloped. In addition, removing NMNAT2 from established axons initiates axon death by Wallerian degeneration. We report here on two stillborn siblings with fetal akinesia deformation sequence (FADS), severely reduced skeletal muscle mass and hydrops fetalis. Clinical exome sequencing identified compound heterozygous NMNAT2 variant alleles in both cases. Both protein variants are incapable of supporting axon survival in mouse primary neuron cultures when overexpressed. In vitro assays demonstrate altered protein stability and/or defects in NAD+ synthesis and chaperone functions. Thus, both patient NMNAT2 alleles are null or severely hypo-morphic. These data indicate a previously unknown role for NMNAT2 in human neurological development and provide the first direct molecular evidence to support the involvement of Wallerian degeneration in a human axonal disorder. SIGNIFICANCE: Nicotinamide Mononucleotide Adenylyltransferase 2 (NMNAT2) both synthesizes the electron carrier Nicotinamide Adenine Dinucleotide (NAD+) and acts a protein chaperone. NMNAT2 has emerged as a major neuron survival factor. Overexpression of NMNAT2 protects neurons from Wallerian degeneration after injury and declining levels of NMNAT2 have been implicated in neurodegeneration. While the role of NMNAT2 in neurodegeneration has been extensively studied, the role of NMNAT2 in human development remains unclear. In this work, we present the first human variants in NMNAT2 identified in two fetuses with severe skeletal muscle hypoplasia and fetal akinesia. Functional studies in vitro showed that the mutations impair both NMNAT2 NAD+ synthase and chaperone functions. This work identifies the critical role of NMNAT2 in human development.
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Affiliation(s)
- Marshall Lukacs
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45229, USA..
| | - Jonathan Gilley
- John van Geest Centre for Brain Repair, University of Cambridge, ED Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.; Signalling ISPG, The Babraham Institute, Babraham, Cambridge CB22 3AT, UK.
| | - Yi Zhu
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Giuseppe Orsomando
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Via Ranieri 67, 60131, Ancona, Italy.
| | - Carlo Angeletti
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Via Ranieri 67, 60131, Ancona, Italy.
| | - Jiaqi Liu
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, Shandong 264005, China.
| | - Xiuna Yang
- John van Geest Centre for Brain Repair, University of Cambridge, ED Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Joun Park
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Robert J Hopkin
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45229, USA..
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, University of Cambridge, ED Adrian Building, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.; Signalling ISPG, The Babraham Institute, Babraham, Cambridge CB22 3AT, UK.
| | - R Grace Zhai
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA; School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, Shandong 264005, China.
| | - Rolf W Stottmann
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45229, USA.; Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45229, USA..
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Yaku K, Okabe K, Nakagawa T. NAD metabolism: Implications in aging and longevity. Ageing Res Rev 2018; 47:1-17. [PMID: 29883761 DOI: 10.1016/j.arr.2018.05.006] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/31/2018] [Accepted: 05/31/2018] [Indexed: 12/20/2022]
Abstract
Nicotinamide adenine dinucleotide (NAD) is an important co-factor involved in numerous physiological processes, including metabolism, post-translational protein modification, and DNA repair. In living organisms, a careful balance between NAD production and degradation serves to regulate NAD levels. Recently, a number of studies have demonstrated that NAD levels decrease with age, and the deterioration of NAD metabolism promotes several aging-associated diseases, including metabolic and neurodegenerative diseases and various cancers. Conversely, the upregulation of NAD metabolism, including dietary supplementation with NAD precursors, has been shown to prevent the decline of NAD and exhibits beneficial effects against aging and aging-associated diseases. In addition, many studies have demonstrated that genetic and/or nutritional activation of NAD metabolism can extend the lifespan of diverse organisms. Collectively, it is clear that NAD metabolism plays important roles in aging and longevity. In this review, we summarize the basic functions of the enzymes involved in NAD synthesis and degradation, as well as the outcomes of their dysregulation in various aging processes. In addition, a particular focus is given on the role of NAD metabolism in the longevity of various organisms, with a discussion of the remaining obstacles in this research field.
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Kuribayashi H, Baba Y, Iwagawa T, Arai E, Murakami A, Watanabe S. Roles of Nmnat1 in the survival of retinal progenitors through the regulation of pro-apoptotic gene expression via histone acetylation. Cell Death Dis 2018; 9:891. [PMID: 30166529 PMCID: PMC6117278 DOI: 10.1038/s41419-018-0907-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 11/21/2022]
Abstract
Leber congenital amaurosis (LCA) is a severe, genetically heterogeneous dystrophy of the retina and mutations in the nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) gene is one of causal factors of LCA. NMNAT1 is a nuclear enzyme essential for nicotinamide adenine dinucleotide (NAD) biosynthesis pathways, but the mechanisms underlying the LCA pathology and whether NMNAT1 has a role in normal retinal development remain unclear. Thus, we examined the roles of Nmnat1 in retinal development via short hairpin (sh)-RNA-mediated downregulation. Retinal explants expressing sh-Nmnat1 showed large numbers of apoptotic retinal progenitor cells in the inner half of the neuroblastic layer. Decreased intracellular NAD content was observed and the addition of NAD to the culture medium attenuated sh-Nmnat1-induced apoptosis. Of the nuclear Sirtuin (Sirt) family, the expression of sh-Sirt1 and sh-Sirt6 resulted in a phenotype similar to that of sh-Nmnat1. Sirt proteins are histone deacetylases and the expression of sh-Nmnat1 increased the levels of acetylated histones H3 and H4 in the retina. Expression of sh-Nmnat1 resulted in significantly increased expression of Noxa and Fas, two pro-apoptotic genes. Acetylation of the genomic 5′-untranslated regions of Noxa and Fas loci was upregulated by sh-Nmnat1 expression. The co-expression of sh-Fas with sh-Nmnat1 reduced the number of apoptotic cells induced by sh-Nmnat1 expression alone. Taken together, our data suggested that the increased expression of Noxa and Fas explains, at least in part, the phenotype associated with sh-Nmnat1 in the retina. Taken together, these findings demonstrate the importance of the NAD biosynthesis pathway in normal development of the retina.
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Affiliation(s)
- Hiroshi Kuribayashi
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Yukihiro Baba
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Toshiro Iwagawa
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Eisuke Arai
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.,Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Akira Murakami
- Graduate School of Medicine, Juntendo University, Tokyo, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
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Diagnostic and Therapeutic Challenges. Retina 2018; 39:2053-2058. [PMID: 30074523 DOI: 10.1097/iae.0000000000002277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Sun W, Zhang Q. A novel variant in IDH3A identified in a case with Leber congenital amaurosis accompanied by macular pseudocoloboma. Ophthalmic Genet 2018; 39:662-663. [DOI: 10.1080/13816810.2018.1502788] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Molecular Diagnosis of 34 Japanese Families with Leber Congenital Amaurosis Using Targeted Next Generation Sequencing. Sci Rep 2018; 8:8279. [PMID: 29844330 PMCID: PMC5974356 DOI: 10.1038/s41598-018-26524-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/14/2018] [Indexed: 02/07/2023] Open
Abstract
Leber congenital amaurosis (LCA) is a genetically and clinically heterogeneous disease, and represents the most severe form of inherited retinal dystrophy (IRD). The present study reports the mutation spectra and frequency of known LCA and IRD-associated genes in 34 Japanese families with LCA (including three families that were previously reported). A total of 74 LCA- and IRD-associated genes were analysed via targeted-next generation sequencing (TS), while recently discovered LCA-associated genes, as well as known variants not able to be screened using this approach, were evaluated via additional Sanger sequencing, long-range polymerase chain reaction, and/or copy number variation analyses. The results of these analyses revealed 30 potential pathogenic variants in 12 (nine LCA-associated and three other IRD-associated) genes among 19 of the 34 analysed families. The most frequently mutated genes were CRB1, NMNAT1, and RPGRIP1. The results also showed the mutation spectra and frequencies identified in the analysed Japanese population to be distinctly different from those previously identified for other ethnic backgrounds. Finally, the present study, which is the first to conduct a NGS-based molecular diagnosis of a large Japanese LCA cohort, achieved a detection rate of approximately 56%, indicating that TS is a valuable method for molecular diagnosis of LCA cases in the Japanese population.
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NMNAT1 E257K variant, associated with Leber Congenital Amaurosis (LCA9), causes a mild retinal degeneration phenotype. Exp Eye Res 2018; 173:32-43. [PMID: 29674119 DOI: 10.1016/j.exer.2018.04.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 03/18/2018] [Accepted: 04/13/2018] [Indexed: 01/25/2023]
Abstract
NMNAT1 (nicotinamide mononucleotide adenylyltransferase 1) encodes a rate-limiting enzyme that catalyzes the biosynthesis of NAD+ and plays a role in neuroprotection. Mutations in NMNAT1 have been identified to cause a recessive, non-syndromic early form of blindness genetically defined as Leber Congenital Amaurosis 9 (LCA9). One of the most common alleles reported so far in NMNAT1 is the c.769G > A (E257K) missense mutation, which occurs in 70% of all LCA9 cases. However, given its relatively high population frequency and the observation of individuals with homozygous E257K variant without phenotype, the pathogenicity of this allele has been questioned. To address this issue, we have studied the pathogenic effects of this allele by generating a knock-in mouse model. Interestingly, no obvious morphological or functional defects are observed in Nmnat1 E257K homozygous mice up to one year old, even after light-damage. Together with the previous clinical reports, we propose that the E257K allele is a weak hypomorphic allele that has significantly reduced penetrance in the homozygous state. In contrast, compound heterozygous Nmnat1E257K/- mice exhibit photoreceptor defects which are exacerbated upon exposure to light. Furthermore, retina tissue- specific Nmnat1 conditional knockout mice exhibit photoreceptor degeneration before the retina has terminally differentiated. These findings suggest that NMNAT1 plays an important role in photoreceptors and is likely involved in both retinal development and maintenance of photoreceptor integrity.
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Special Issue Introduction: Inherited Retinal Disease: Novel Candidate Genes, Genotype-Phenotype Correlations, and Inheritance Models. Genes (Basel) 2018; 9:genes9040215. [PMID: 29659558 PMCID: PMC5924557 DOI: 10.3390/genes9040215] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 04/13/2018] [Indexed: 02/06/2023] Open
Abstract
Inherited retinal diseases (IRDs) are genetically and clinically heterogeneous disorders.[...].
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Li Y, Pan Q, Gu YS. Phenotype-genotype correlation with Sanger sequencing identified retinol dehydrogenase 12 (RDH12) compound heterozygous variants in a Chinese family with Leber congenital amaurosis. J Zhejiang Univ Sci B 2018; 18:421-429. [PMID: 28471114 DOI: 10.1631/jzus.b1600156] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Leber congenital amaurosis (LCA) is a group of clinically and genetically heterogeneous retinal dystrophy. To date, 22 genes are known to be responsible for LCA, and some specific phenotypic features could provide significant prognostic information for a potential genetic etiology. This study is to identify gene variants responsible for LCA in a Chinese family using direct Sanger sequencing, with the help of phenotype-genotype correlations. METHODS A Chinese family with six members including two individuals affected with LCA was studied. All patients underwent a complete ophthalmic examination. Based on phenotype-genotype correlation, direct Sanger sequencing was performed to identify the candidate gene on all family members and normal controls. Targeted next-generation sequencing was used to exclude other known LCA genes. RESULTS By Sanger sequencing, we identified two novel missense variants in the retinol dehydrogenase 12 (RDH12) gene: a c.164C>A transversion predicting a p.T55K substitution, and a c.535C>G transversion predicting a p.H179D substitution. The two affected subjects carried both RDH12 variants, while their parents and offspring carried only one of heterozygous variants, showing complete cosegregation of the variants. The compound heterozygous variants were not present in 600 normal controls. Besides, the RDH12 variants were confirmed by targeted next-generation sequencing. CONCLUSIONS The RDH12 compound heterozygous variants might be the cause of the LCA family. Our study adds to the molecular spectrum of RDH12-related retinopathy and offers an effective example of the power of phenotype-genotype correlations in molecular diagnosis of LCA.
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Affiliation(s)
- Yun Li
- Department of Ophthalmology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
| | - Qing Pan
- Department of Ophthalmology, Zhejiang Provincial People's Hospital, Hangzhou 310014, China
| | - Yang-Shun Gu
- Department of Ophthalmology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China
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Rossi F, Geiszler PC, Meng W, Barron MR, Prior M, Herd-Smith A, Loreto A, Lopez MY, Faas H, Pardon MC, Conforti L. NAD-biosynthetic enzyme NMNAT1 reduces early behavioral impairment in the htau mouse model of tauopathy. Behav Brain Res 2018; 339:140-152. [PMID: 29175372 PMCID: PMC5769520 DOI: 10.1016/j.bbr.2017.11.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/08/2017] [Accepted: 11/22/2017] [Indexed: 11/04/2022]
Abstract
NAD metabolism and the NAD biosynthetic enzymes nicotinamide nucleotide adenylyltransferases (NMNATs) are thought to play a key neuroprotective role in tauopathies, including Alzheimer's disease. Here, we investigated whether modulating the expression of the NMNAT nuclear isoform NMNAT1, which is important for neuronal maintenance, influences the development of behavioral and neuropathological abnormalities in htau mice, which express non-mutant human tau isoforms and represent a model of tauopathy relevant to Alzheimer's disease. Prior to the development of cognitive symptoms, htau mice exhibit tau hyperphosphorylation associated with a selective deficit in food burrowing, a behavior reminiscent to activities of daily living which are impaired early in Alzheimer's disease. We crossed htau mice with Nmnat1 transgenic and knockout mice and tested the resulting offspring until the age of 6 months. We show that overexpression of NMNAT1 ameliorates the early deficit in food burrowing characteristic of htau mice. At 6 months of age, htau mice did not show neurodegenerative changes in both the cortex and hippocampus, and these were not induced by downregulating NMNAT1 levels. Modulating NMNAT1 levels produced a corresponding effect on NMNAT enzymatic activity but did not alter NAD levels in htau mice. Although changes in local NAD levels and subsequent modulation of NAD-dependent enzymes cannot be ruled out, this suggests that the effects seen on behavior may be due to changes in tau phosphorylation. Our results suggest that increasing NMNAT1 levels can slow the progression of symptoms and neuropathological features of tauopathy, but the underlying mechanisms remain to be established.
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Affiliation(s)
- Francesca Rossi
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK; Department of Biomedical Sciences, Cagliari University, Cagliari 09042, Italy
| | - Philippine C Geiszler
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Weina Meng
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Matthew R Barron
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Malcolm Prior
- Department of Biomedical Sciences, Cagliari University, Cagliari 09042, Italy
| | - Anna Herd-Smith
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Andrea Loreto
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Maria Yanez Lopez
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Queen's Medical Centre, Medical School, Nottingham NG7 2UH, UK; Faculty of Medicine, Department of Medicine, Imperial College London, Burlington Danes, Hammersmith campus, London W12 0NN, UK
| | - Henryk Faas
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Queen's Medical Centre, Medical School, Nottingham NG7 2UH, UK
| | - Marie-Christine Pardon
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK.
| | - Laura Conforti
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
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Rim JH, Lee ST, Gee HY, Lee BJ, Choi JR, Park HW, Han SH, Han J. Accuracy of Next-Generation Sequencing for Molecular Diagnosis in Patients With Infantile Nystagmus Syndrome. JAMA Ophthalmol 2017; 135:1376-1385. [PMID: 29145603 PMCID: PMC6583550 DOI: 10.1001/jamaophthalmol.2017.4859] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/23/2017] [Indexed: 01/10/2023]
Abstract
Importance Infantile nystagmus syndrome (INS) is a group of disorders presenting with genetic and clinical heterogeneities that have challenged the genetic and clinical diagnoses of INS. Precise molecular diagnosis in early infancy may result in more accurate genetic counseling and improved patient management. Objective To assess the accuracy of genomic data from next-generation sequencing (NGS) and phenotypic data to enhance the definitive diagnosis of INS. Design, Setting, and Participants A single-center retrospective case series was conducted in 48 unrelated, consecutive patients with INS, with or without associated ocular or systemic conditions, who underwent genetic testing between June 1, 2015, and January 31, 2017. Next-generation sequencing analysis was performed using a target panel that included 113 genes associated with INS (n = 47) or a TruSight One sequencing panel that included 4813 genes associated with known human phenotypes (n = 1). Variants were filtered and prioritized by in-depth clinical review, and finally classified according to the American College of Medical Genetics and Genomics guidelines. Patients underwent a detailed ophthalmic examination, including electroretinography and optical coherence tomography, if feasible. Main Outcomes and Measures Diagnostic yield of targeted NGS testing. Results Among the 48 patients (21 female and 27 male; mean [SD] age at genetic testing, 9.2 [10.3] years), 8 had a family history of nystagmus and 40 were simplex. All patients were of a single ethnicity (Korean). Genetic variants that were highly likely to be causative were identified in 28 of the 48 patients, corresponding to a molecular diagnostic yield of 58.3% (95% CI, 44.4%-72.2%). FRMD7, GPR143, and PAX6 mutations appeared to be the major genetic causes of familial INS. A total of 10 patients (21%) were reclassified to a different diagnosis based on results of NGS testing, enabling accurate clinical management. Conclusions and Relevance These findings suggest that NGS is an accurate diagnostic tool to differentiate causes of INS because diagnostic tests, such as electroretinography and optical coherence tomography, are not easily applicable in young infants. Accurate application of NGS using a standardized, stepwise, team-based approach in early childhood not only facilitated early molecular diagnosis but also led to improved personalized management in patients with INS.
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Affiliation(s)
- John Hoon Rim
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Department of Medicine, Yonsei University Graduate School of Medicine, Seoul, Korea
- Department of Pharmacology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Heon Yung Gee
- Department of Medicine, Yonsei University Graduate School of Medicine, Seoul, Korea
- Department of Pharmacology, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Byung Joo Lee
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hye Won Park
- Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Sueng-Han Han
- Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
| | - Jinu Han
- Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea
- Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Biswas P, Duncan JL, Ali M, Matsui H, Naeem MA, Raghavendra PB, Frazer KA, Arts HH, Riazuddin S, Akram J, Hejtmancik JF, Riazuddin SA, Ayyagari R. A mutation in IFT43 causes non-syndromic recessive retinal degeneration. Hum Mol Genet 2017; 26:4741-4751. [PMID: 28973684 PMCID: PMC6075558 DOI: 10.1093/hmg/ddx356] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 09/08/2017] [Accepted: 09/12/2017] [Indexed: 01/12/2023] Open
Abstract
The aim of this work is to identify the molecular cause of autosomal recessive early onset retinal degeneration in a consanguineous pedigree. Seventeen members of a four-generation Pakistani family were recruited and underwent a detailed ophthalmic examination. Exomes of four affected and two unaffected individuals were sequenced. Variants were filtered using exomeSuite to identify rare potentially pathogenic variants in genes expressed in the retina and/or brain and consistent with the pattern of inheritance. Effect of the variant observed in the gene Intraflagellar Transport Protein 43 (IFT43) was studied by heterologous expression in mIMCD3 and MDCK cells. Expression and sub-cellular localization of IFT43 in the retina and transiently transfected cells was examined by RT-PCR, western blot analysis, and immunohistochemistry. Affected members were diagnosed with early onset non-syndromic progressive retinal degeneration and the presence of bone spicules distributed throughout the retina at younger ages while the older affected members showed severe central choroidal atrophy. Whole-exome sequencing analysis identified a novel homozygous c.100 G > A change in IFT43 segregating with retinal degeneration and not present in ethnicity-matched controls. Immunostaining showed IFT43 localized in the photoreceptors, and to the tip of the cilia in transfected mIMCD3 and MDCK cells. The cilia in mIMCD3 and MDCK cells expressing mutant IFT43 were found to be significantly shorter (P < 0.001) than cells expressing wild-type IFT43. Our studies identified a novel homozygous mutation in the ciliary protein IFT43 as the underlying cause of recessive inherited retinal degeneration. This is the first report demonstrating the involvement of IFT43 in retinal degeneration.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India
| | - Jacque L Duncan
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Muhammad Ali
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiroko Matsui
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Pongali B Raghavendra
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India
- School of Regenerative Medicine, Manipal University, Bangalore, India
| | - Kelly A Frazer
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Pediatrics, Division of Genome Information Sciences, Rady Children‘s Hospital, San Diego, CA, USA
| | - Heleen H Arts
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- Allama Iqbal Medical College, University of Health Sciences Lahore, Pakistan
- National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences Lahore, Pakistan
- National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, MD, USA
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
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45
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Nash BM, Symes R, Goel H, Dinger ME, Bennetts B, Grigg JR, Jamieson RV. NMNAT1 variants cause cone and cone-rod dystrophy. Eur J Hum Genet 2017; 26:428-433. [PMID: 29184169 DOI: 10.1038/s41431-017-0029-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/13/2017] [Accepted: 10/10/2017] [Indexed: 11/09/2022] Open
Abstract
Cone and cone-rod dystrophies (CD and CRD, respectively) are degenerative retinal diseases that predominantly affect the cone photoreceptors. The underlying disease gene is not known in approximately 75% of autosomal recessive cases. Variants in NMNAT1 cause a severe, early-onset retinal dystrophy called Leber congenital amaurosis (LCA). We report two patients where clinical phenotyping indicated diagnoses of CD and CRD, respectively. NMNAT1 variants were identified, with Case 1 showing an extremely rare homozygous variant c.[271G > A] p.(Glu91Lys) and Case 2 compound heterozygous variants c.[53 A > G];[769G > A] p.(Asn18Ser);(Glu257Lys). The detailed variant analysis, in combination with the observation of an associated macular atrophy phenotype, indicated that these variants were disease-causing. This report demonstrates that the variants in NMNAT1 may cause CD or CRD associated with macular atrophy. Genetic investigations of the patients with CD or CRD should include NMNAT1 in the genes examined.
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Affiliation(s)
- Benjamin M Nash
- Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia.,Disciplines of Genetic Medicine, and Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.,Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Richard Symes
- Discipline of Ophthalmology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | | | - Marcel E Dinger
- Kinghorn Centre for Clinical Genomics, Garvan Institute for Medical Research, Sydney, NSW, Australia.,St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Bruce Bennetts
- Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - John R Grigg
- Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia.,Discipline of Ophthalmology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Robyn V Jamieson
- Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia. .,Disciplines of Genetic Medicine, and Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia. .,Department of Clinical Genetics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia.
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46
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NAMPT-Mediated NAD(+) Biosynthesis Is Essential for Vision In Mice. Cell Rep 2017; 17:69-85. [PMID: 27681422 DOI: 10.1016/j.celrep.2016.08.073] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 07/26/2016] [Accepted: 08/19/2016] [Indexed: 01/20/2023] Open
Abstract
Photoreceptor death is the endpoint of many blinding diseases. Identifying unifying pathogenic mechanisms in these diseases may offer global approaches for facilitating photoreceptor survival. We found that rod or cone photoreceptor-specific deletion of nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme in the major NAD(+) biosynthetic pathway beginning with nicotinamide, caused retinal degeneration. In both cases, we could rescue vision with nicotinamide mononucleotide (NMN). Significantly, retinal NAD(+) deficiency was an early feature of multiple mouse models of retinal dysfunction, including light-induced degeneration, streptozotocin-induced diabetic retinopathy, and age-associated dysfunction. Mechanistically, NAD(+) deficiency caused metabolic dysfunction and consequent photoreceptor death. We further demonstrate that the NAD(+)-dependent mitochondrial deacylases SIRT3 and SIRT5 play important roles in retinal homeostasis and that NAD(+) deficiency causes SIRT3 dysfunction. These findings demonstrate that NAD(+) biosynthesis is essential for vision, provide a foundation for future work to further clarify the mechanisms involved, and identify a unifying therapeutic target for diverse blinding diseases.
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Di Iorio V, Karali M, Brunetti-Pierri R, Filippelli M, Di Fruscio G, Pizzo M, Mutarelli M, Nigro V, Testa F, Banfi S, Simonelli F. Clinical and Genetic Evaluation of a Cohort of Pediatric Patients with Severe Inherited Retinal Dystrophies. Genes (Basel) 2017; 8:genes8100280. [PMID: 29053603 PMCID: PMC5664130 DOI: 10.3390/genes8100280] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/02/2017] [Accepted: 10/13/2017] [Indexed: 12/30/2022] Open
Abstract
We performed a clinical and genetic characterization of a pediatric cohort of patients with inherited retinal dystrophy (IRD) to identify the most suitable cases for gene therapy. The cohort comprised 43 patients, aged between 2 and 18 years, with severe isolated IRD at the time of presentation. The ophthalmological characterization also included assessment of the photoreceptor layer integrity in the macular region (ellipsoid zone (EZ) band). In parallel, we carried out a targeted, next-generation sequencing (NGS)-based analysis using a panel that covers over 150 genes with either an established or a candidate role in IRD pathogenesis. Based on the ophthalmological assessment, the cohort was composed of 24 Leber congenital amaurosis, 14 early onset retinitis pigmentosa, and 5 achromatopsia patients. We identified causative mutations in 58.1% of the cases. We also found novel genotype-phenotype correlations in patients harboring mutations in the CEP290 and CNGB3 genes. The EZ band was detectable in 40% of the analyzed cases, also in patients with genotypes usually associated with severe clinical manifestations. This study provides the first detailed clinical-genetic assessment of severe IRDs with infantile onset and lays the foundation of a standardized protocol for the selection of patients that are more likely to benefit from gene replacement therapeutic approaches.
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Affiliation(s)
- Valentina Di Iorio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania Luigi Vanvitelli, via Pansini 5, Naples 80131, Italy.
| | - Marianthi Karali
- Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, Università degli Studi della Campania Luigi Vanvitelli, via Luigi De Crecchio 7, Naples 80138, Italy.
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, Pozzuoli 80078, Italy.
| | - Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania Luigi Vanvitelli, via Pansini 5, Naples 80131, Italy.
| | - Mariaelena Filippelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania Luigi Vanvitelli, via Pansini 5, Naples 80131, Italy.
| | - Giuseppina Di Fruscio
- Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, Università degli Studi della Campania Luigi Vanvitelli, via Luigi De Crecchio 7, Naples 80138, Italy.
| | - Mariateresa Pizzo
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, Pozzuoli 80078, Italy.
| | - Margherita Mutarelli
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, Pozzuoli 80078, Italy.
| | - Vincenzo Nigro
- Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, Università degli Studi della Campania Luigi Vanvitelli, via Luigi De Crecchio 7, Naples 80138, Italy.
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, Pozzuoli 80078, Italy.
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania Luigi Vanvitelli, via Pansini 5, Naples 80131, Italy.
| | - Sandro Banfi
- Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, Università degli Studi della Campania Luigi Vanvitelli, via Luigi De Crecchio 7, Naples 80138, Italy.
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, Pozzuoli 80078, Italy.
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania Luigi Vanvitelli, via Pansini 5, Naples 80131, Italy.
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48
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Galindo R, Banks Greenberg M, Araki T, Sasaki Y, Mehta N, Milbrandt J, Holtzman DM. NMNAT3 is protective against the effects of neonatal cerebral hypoxia-ischemia. Ann Clin Transl Neurol 2017; 4:722-738. [PMID: 29046881 PMCID: PMC5634348 DOI: 10.1002/acn3.450] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/11/2017] [Accepted: 07/14/2017] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVE To determine whether the NAD+ biosynthetic protein, nicotinamide mononucleotide adenylyltransferase-3 (NMNAT3), is a neuroprotective inducible enzyme capable of decreasing cerebral injury after neonatal hypoxia-ischemia (H-I) and reducing glutamate receptor-mediated excitotoxic neurodegeneration of immature neurons. METHODS Using NMNAT3-overexpressing mice we investigated whether increases in brain NMNAT3 reduced cerebral tissue loss following H-I. We then employed biochemical methods from injured neonatal brains to examine the inducibility of NMNAT3 and the mechanism of NMNAT3-dependent neuroprotection. Using AAV8-mediated vectors for in vitro neuronal NMNAT3 knockdown, we then examine the endogenous role of this protein on immature neuronal survival prior and following NMDA receptor-mediated excitotoxicity. RESULTS NMNAT3 mRNA and protein levels increased after neonatal H-I. In addition, NMNAT3 overexpression decreased cortical and hippocampal tissue loss 7 days following injury. We further show that the NMNAT3 neuroprotective mechanism involves a decrease in calpastatin degradation, and a decrease in caspase-3 activity and calpain-mediated cleavage. Conversely, NMNAT3 knockdown of cortical and hippocampal neurons in vitro caused neuronal degeneration and increased excitotoxic cell death. The neurodegenerative effects of NMNAT3 knockdown were counteracted by exogenous upregulation of NMNAT3. CONCLUSIONS Our observations provide new insights into the neuroprotective mechanisms of NMNATs in the injured developing brain, adding NMNAT3 as an important neuroprotective enzyme in neonatal H-I via inhibition of apoptotic and necrotic neurodegeneration. Interestingly, we find that endogenous NMNAT3 is an inducible protein important for maintaining the survival of immature neurons. Future studies aimed at uncovering the mechanisms of NMNAT3 upregulation and neuroprotection may offer new therapies against the effects of hypoxic-ischemic encephalopathy.
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Affiliation(s)
- Rafael Galindo
- Department of NeurologyHope Center for Neurological DisordersWashington UniversitySt. LouisMissouri63110
| | - Marianne Banks Greenberg
- Department of NeurologyHope Center for Neurological DisordersWashington UniversitySt. LouisMissouri63110
| | - Toshiyuki Araki
- Department of Peripheral Nervous System ResearchNational Institute of NeuroscienceKodairaTokyoJapan
| | - Yo Sasaki
- Department of GeneticsWashington UniversitySt. LouisMissouri63110
| | - Nehali Mehta
- Department of NeurologyHope Center for Neurological DisordersWashington UniversitySt. LouisMissouri63110
| | | | - David M. Holtzman
- Department of NeurologyHope Center for Neurological DisordersWashington UniversitySt. LouisMissouri63110
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49
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Thompson JA, De Roach JN, McLaren TL, Montgomery HE, Hoffmann LH, Campbell IR, Chen FK, Mackey DA, Lamey TM. The genetic profile of Leber congenital amaurosis in an Australian cohort. Mol Genet Genomic Med 2017; 5:652-667. [PMID: 29178642 PMCID: PMC5702575 DOI: 10.1002/mgg3.321] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 12/21/2022] Open
Abstract
Background Leber congenital amaurosis (LCA) is a severe visual impairment responsible for infantile blindness, representing ~5% of all inherited retinal dystrophies. LCA encompasses a group of heterogeneous disorders, with 24 genes currently implicated in pathogenesis. Such clinical and genetic heterogeneity poses great challenges for treatment, with personalized therapies anticipated to be the best treatment candidates. Unraveling the individual genetic etiology of disease is a prerequisite for personalized therapies, and could identify potential treatment candidates, inform patient management, and discriminate syndromic forms of disease. Methods We have genetically analyzed 45 affected and 82 unaffected individuals from 34 unrelated LCA pedigrees using predominantly next‐generation sequencing and Array CGH technology. Results We present the molecular findings for an Australian LCA cohort, sourced from the Australian Inherited Retinal Disease Registry & DNA Bank. CEP290 and GUCY2D mutations, each represent 19% of unrelated LCA cases, followed by NMNAT1 (12%). Genetic subtypes were consistent with other reports, and were resolved in 90% of this cohort. Conclusion The high resolution rate achieved, equivalent to recent findings using whole exome/genome sequencing, reflects the progression from hypothesis (LCA Panel) to non‐hypothesis (RD Panel) testing and, coupled with Array CGH analysis, is a highly effective first‐tier test for LCA.
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Affiliation(s)
- 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
| | - John N De Roach
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
| | - Terri L McLaren
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Hannah E Montgomery
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Ling H Hoffmann
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Isabella R Campbell
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia
| | - Fred K Chen
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.,Lions Eye Institute, Nedlands, Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - David A Mackey
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia.,Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Tina M Lamey
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.,Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
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50
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Khan AO, Budde BS, Nürnberg P, Kawalia A, Lenzner S, Bolz HJ. Genome-wide linkage and sequence analysis challenge CCDC66 as a human retinal dystrophy candidate gene and support a distinct NMNAT1-related fundus phenotype. Clin Genet 2017; 93:149-154. [PMID: 28369829 DOI: 10.1111/cge.13022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/20/2017] [Accepted: 03/23/2017] [Indexed: 02/06/2023]
Abstract
To uncover the genotype underlying early-onset cone-rod dystrophy and central nummular macular atrophic lesion in 2 siblings from an endogamous Arab family, we performed targeted next-generation sequencing (NGS) of 44 retinal dystrophy genes, whole-exome sequencing (WES) and genome-wide linkage analysis. Targeted NGS and WES in the index patient highlighted 2 homozygous variants, a CCDC66 frameshift deletion and a novel missense NMNAT1 variant, c.500G>A (p.Asn167Ser). Linkage and segregation analysis excluded the CCDC66 variant and confirmed the NMNAT1 mutation. Biallelic NMNAT1 mutations cause Leber congenital amaurosis with a central nummular macular atrophic lesion (LCA9). The NMNAT1 mutation reported here underlied cone-rod dystrophy rather than LCA but the fundus lesion was compatible with that of LCA9 patients, highlighting that such a fundus appearance should raise suspicion for biallelic mutations in NMNAT1 when in the context of any retinal dystrophy. Although Ccdc66 mutations have been proposed to cause retinal disease in dogs, our results and public databases challenge CCDC66 as a candidate gene for human retinal dystrophy.
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Affiliation(s)
- A O Khan
- Eye Institute, Cleveland Clinic Abu Dhabi (CCAD), Abu Dhabi, United Arab Emirates
| | - B S Budde
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - P Nürnberg
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - A Kawalia
- Cologne Center for Genomics (CCG) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - S Lenzner
- Bioscientia, Center for Human Genetics, Ingelheim, Germany
| | - H J Bolz
- Bioscientia, Center for Human Genetics, Ingelheim, Germany.,Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
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