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Zin EA, Ozturk BE, Dalkara D, Byrne LC. Developing New Vectors for Retinal Gene Therapy. Cold Spring Harb Perspect Med 2023; 13:a041291. [PMID: 36987583 PMCID: PMC10691475 DOI: 10.1101/cshperspect.a041291] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Since their discovery over 55 years ago, adeno-associated virus (AAV) vectors have become powerful tools for experimental and therapeutic in vivo gene delivery, particularly in the retina. Increasing knowledge of AAV structure and biology has propelled forward the development of engineered AAV vectors with improved abilities for gene delivery. However, major obstacles to safe and efficient therapeutic gene delivery remain, including tropism, inefficient and untargeted gene delivery, and limited carrying capacity. Additional improvements to AAV vectors will be required to achieve therapeutic benefit while avoiding safety issues. In this review, we provide an overview of recent methods for engineering-enhanced AAV capsids, as well as remaining challenges that must be overcome to achieve optimized therapeutic gene delivery in the eye.
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Affiliation(s)
- Emilia A Zin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France
| | - Bilge E Ozturk
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012 Paris, France
| | - Leah C Byrne
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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2
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Boye SL, O’Riordan C, Morris J, Lukason M, Compton D, Baek R, Elmore DM, Peterson J, Fajardo D, McCullough KT, Scaria A, McVie-Wylie A, Boye SE. Preclinical studies in support of phase I/II clinical trials to treat GUCY2D-associated Leber congenital amaurosis. Mol Ther Methods Clin Dev 2023; 28:129-145. [PMID: 36654798 PMCID: PMC9830033 DOI: 10.1016/j.omtm.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Mutations in GUCY2D are associated with severe early-onset retinal dystrophy, Leber congenital amaurosis type 1 (LCA1), a leading cause of blindness in children. Despite a high degree of visual disturbance stemming from photoreceptor dysfunction, patients with LCA1 largely retain normal photoreceptor structure, suggesting that they are good candidates for gene replacement therapy. The purpose of this study was to conduct the preclinical and IND-enabling experiments required to support clinical application of AAV5-hGRK1-GUCY2D in patients harboring biallelic recessive mutations in GUCY2D. Preclinical studies were conducted in mice to evaluate the effect of vector manufacturing platforms and transgene species on the therapeutic response. Dose-ranging studies were conducted in cynomolgus monkeys to establish the minimum dose required for efficient photoreceptor transduction. Good laboratory practice (GLP) studies evaluated systemic biodistribution in rats and toxicology in non-human primates (NHPs). These results expanded our knowledge of dose response for an AAV5-vectored transgene under control of the human rhodopsin kinase (hGRK1) promoter in NHPs with respect to photoreceptor transduction and safety and, in combination with the rat biodistribution and mouse efficacy studies, informed the design of a first-in-human clinical study in patients with LCA1.
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Affiliation(s)
- Sanford L. Boye
- Powell Gene Therapy Center, Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA
| | | | | | | | | | | | | | | | | | | | | | | | - Shannon E. Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, PO Box 100296, Gainesville, FL 32610, USA
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Jacobson SG, Cideciyan AV, Ho AC, Roman AJ, Wu V, Garafalo AV, Sumaroka A, Krishnan AK, Swider M, Mascio AA, Kay CN, Yoon D, Fujita KP, Boye SL, Peshenko IV, Dizhoor AM, Boye SE. Night vision restored in days after decades of congenital blindness. iScience 2022; 25:105274. [PMID: 36274938 PMCID: PMC9579015 DOI: 10.1016/j.isci.2022.105274] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/29/2022] [Accepted: 09/30/2022] [Indexed: 11/29/2022] Open
Abstract
Signaling of vision to the brain starts with the retinal phototransduction cascade which converts visible light from the environment into chemical changes. Vision impairment results when mutations inactivate proteins of the phototransduction cascade. A severe monogenically inherited blindness, Leber congenital amaurosis (LCA), is caused by mutations in the GUCY2D gene, leading to a molecular defect in the production of cyclic GMP, the second messenger of phototransduction. We studied two patients with GUCY2D-LCA who were undergoing gene augmentation therapy. Both patients had large deficits in rod photoreceptor-based night vision before intervention. Within days of therapy, rod vision in both patients changed dramatically; improvements in visual function and functional vision in these hyper-responding patients reached more than 3 log10 units (1000-fold), nearing healthy rod vision. Quick activation of the complex molecular pathways from retinal photoreceptor to visual cortex and behavior is thus possible in patients even after being disabled and dormant for decades.
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Affiliation(s)
- Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Allen C. Ho
- Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vivian Wu
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexandra V. Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arun K. Krishnan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Abraham A. Mascio
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Dan Yoon
- Atsena Therapeutics, Inc., Durham, NC 27709, USA
| | | | - Sanford L. Boye
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL 32601, USA
| | - Igor V. Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA 19027, USA
| | | | - Shannon E. Boye
- Department of Pediatrics, Division of Cellular and Molecular Therapy, University of Florida College of Medicine, Gainesville, FL 32611, USA
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Qian X, Liu H, Fu S, Lu J, Hung YT, Turner C, Gu H, Chen R. AAV8-Mediated Gene Therapy Rescues Retinal Degeneration Phenotype in a Tlcd3b Knockout Mouse Model. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 35275174 PMCID: PMC8934561 DOI: 10.1167/iovs.63.3.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/22/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to assess the therapeutic efficacy of rAAV8-hGRK1-Tlcd3b in a Tlcd3b-/- mouse model of retinal generation and validate TLCD3B's role as a ceramide synthase in vivo. Methods Using Tlcd3b-/- mice as an inherited retinal disease animal model, we performed subretinal injection of rAAV8-hGRK1-Tlcd3b and evaluated the efficacy of gene replacement therapy. Tlcd3b-/- mice were treated at two time points: postnatal day 21 (P21) and postnatal day 120 (P120) with various dosages. Results Tlcd3b overexpression rescued retinal degeneration in the mutant mice, as indicated by significantly improved photoreceptor function and preservation of photoreceptor cells over the course of 1 year. Although Tlcd3b is expressed in all cell types in the retina, photoreceptor cell-specific expression of Tlcd3b is sufficient to rescue the phenotype, indicating the primary function of TLCD3B is in photoreceptors. Consistent with the idea that TLCD3B is a ceramide synthase, mass spectrometry analyses of the mutant retina indicate the reduction of C16-, C18-, and C20-ceramides in the retina, which are restored with Tlcd3b overexpression. Conclusions Our findings demonstrated the therapeutic efficacy of gene therapy in treating Tlcd3b mutant retina, laying the foundation for developing future therapy for TLCD3B retinopathy.
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Affiliation(s)
- Xinye Qian
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States
| | - Hehe Liu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States
| | - Shangyi Fu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States
- School of Medicine, Baylor College of Medicine, Houston, Texas, United States
| | - Jiaxiong Lu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States
| | - Yu-Ting Hung
- Arizona Metabolomics Laboratory, College of Health Solutions, Arizona State University, Scottsdale, Arizona, United States
| | - Cassidy Turner
- Arizona Metabolomics Laboratory, College of Health Solutions, Arizona State University, Scottsdale, Arizona, United States
| | - Haiwei Gu
- Arizona Metabolomics Laboratory, College of Health Solutions, Arizona State University, Scottsdale, Arizona, United States
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
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5
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Amato A, Arrigo A, Aragona E, Manitto MP, Saladino A, Bandello F, Battaglia Parodi M. Gene Therapy in Inherited Retinal Diseases: An Update on Current State of the Art. Front Med (Lausanne) 2021; 8:750586. [PMID: 34722588 PMCID: PMC8553993 DOI: 10.3389/fmed.2021.750586] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 12/11/2022] Open
Abstract
Background: Gene therapy cannot be yet considered a far perspective, but a tangible therapeutic option in the field of retinal diseases. Although still confined in experimental settings, the preliminary results are promising and provide an overall scenario suggesting that we are not so far from the application of gene therapy in clinical settings. The main aim of this review is to provide a complete and updated overview of the current state of the art and of the future perspectives of gene therapy applied on retinal diseases. Methods: We carefully revised the entire literature to report all the relevant findings related to the experimental procedures and the future scenarios of gene therapy applied in retinal diseases. A clinical background and a detailed description of the genetic features of each retinal disease included are also reported. Results: The current literature strongly support the hope of gene therapy options developed for retinal diseases. Although being considered in advanced stages of investigation for some retinal diseases, such as choroideremia (CHM), retinitis pigmentosa (RP), and Leber's congenital amaurosis (LCA), gene therapy is still quite far from a tangible application in clinical practice for other retinal diseases. Conclusions: Gene therapy is an extremely promising therapeutic tool for retinal diseases. The experimental data reported in this review offer a strong hope that gene therapy will be effectively available in clinical practice in the next years.
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Affiliation(s)
- Alessia Amato
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Emanuela Aragona
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Maria Pia Manitto
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Andrea Saladino
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
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Padhy SK, Takkar B, Narayanan R, Venkatesh P, Jalali S. Voretigene Neparvovec and Gene Therapy for Leber's Congenital Amaurosis: Review of Evidence to Date. APPLICATION OF CLINICAL GENETICS 2020; 13:179-208. [PMID: 33268999 PMCID: PMC7701157 DOI: 10.2147/tacg.s230720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/06/2020] [Indexed: 12/13/2022]
Abstract
Gene therapy has now evolved as the upcoming modality for management of many disorders, both inheritable and non-inheritable. Knowledge of genetics pertaining to a disease has therefore become paramount for physicians across most specialities. Inheritable retinal dystrophies (IRDs) are notorious for progressive and relentless vision loss, frequently culminating in complete blindness in both eyes. Leber’s congenital amaurosis (LCA) is a typical example of an IRD that manifests very early in childhood. Research in gene therapy has led to the development and approval of voretigene neparvovec (VN) for use in patients of LCA with a deficient biallelic RPE65 gene. The procedure involves delivery of a recombinant virus vector that carries the RPE65 gene in the subretinal space. This comprehensive review reports the evidence thus far in support of gene therapy for LCA. We explore and compare the various gene targets including but not limited to RPE65, and discuss the choice of vector and method for ocular delivery. The review details the evolution of gene therapy with VN in a phased manner, concluding with the challenges that lie ahead for its translation for use in communities that differ much both genetically and economically.
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Affiliation(s)
- Srikanta Kumar Padhy
- Vitreoretina and Uveitis Services, L V Prasad Eye Institute, Mithu Tulsi Chanrai Campus, Bhubaneswar, India
| | - Brijesh Takkar
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India.,Center of Excellence for Rare Eye Diseases, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
| | - Raja Narayanan
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India
| | - Pradeep Venkatesh
- Dr RP Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Subhadra Jalali
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Kallam Anji Reddy Campus, L.V. Prasad Eye Institute, Hyderabad, India.,Jasti V. Ramanamma Childrens' Eye Care Centre, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
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7
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Cideciyan AV, Jacobson SG. Leber Congenital Amaurosis (LCA): Potential for Improvement of Vision. Invest Ophthalmol Vis Sci 2019; 60:1680-1695. [PMID: 31009524 PMCID: PMC6892385 DOI: 10.1167/iovs.19-26672] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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8
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Tao Y, Zhu Q, Wang L, Zha X, Teng D, Xu L. Adeno-associated virus (AAV)-mediated neuroprotective effects on the degenerative retina: the therapeutic potential of erythropoietin. Fundam Clin Pharmacol 2019; 34:131-147. [PMID: 31243792 DOI: 10.1111/fcp.12494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/01/2019] [Accepted: 06/20/2019] [Indexed: 12/12/2022]
Abstract
Retinal degeneration (RD) results in photoreceptor loss and irreversible visual impairments. This study sought to alleviate the photoreceptor degeneration via the adeno-associated virus (AAV)-mediated erythropoietin (EPO) therapy. AAV-2/2-mCMV-EPO vectors were constructed and delivered into the subretinal space of a RD model. The retinal morphology, optokinetic behaviour and electrophysiological function of the treated animals were analysed. The subretinal delivery of AAV-2/2 vectors induced robust EPO gene expressions in the retinas. AAV2/2-mediated EPO therapy ameliorated the photoreceptor degeneration and visual impairments of the RD animal model. Furthermore, the multi-electrodes array (MEA) was used to detect the firing activities of retinal ganglion cells. MEA recording showed that the EPO therapy could restrain the spontaneous firing response, enhance the light-induced firing response and preserve the basic configurations of visual signal pathway in RD model. Our MEA assay provided an example to evaluate the potency of pharmacological compounds on retinal plasticity. In conclusion, AAV2/2-mediated EPO therapy can ameliorate the photoreceptor degeneration and rectify the abnormities in visual signal transmission. These beneficial results suggest the AAV vector is a viable therapeutic option for retinopathies with rapidly degenerating kinetics and lay the groundwork for future development of EPO gene therapy.
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Affiliation(s)
- Ye Tao
- Department of Ultrasound, China-Japan Union Hospital of Jilin University, Changchun, 130031, China.,Department of Ophthalmology, Key Lab of Ophthalmology and Visual Science, Chinese PLA General Hospital, Beijing, 100853, China
| | - Qi Zhu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Liqiang Wang
- Department of Ophthalmology, Key Lab of Ophthalmology and Visual Science, Chinese PLA General Hospital, Beijing, 100853, China
| | - Xiaobing Zha
- Department of Rehabilitation, Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Dengke Teng
- Department of Ultrasound, China-Japan Union Hospital of Jilin University, Changchun, 130031, China
| | - Lei Xu
- Department of Thoracic Surgery, China-Japan Union Hospital of Jilin University, Changchun, 130033, China
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9
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McCullough KT, Boye SL, Fajardo D, Calabro K, Peterson JJ, Strang CE, Chakraborty D, Gloskowski S, Haskett S, Samuelsson S, Jiang H, Witherspoon CD, Gamlin PD, Maeder ML, Boye SE. Somatic Gene Editing of GUCY2D by AAV-CRISPR/Cas9 Alters Retinal Structure and Function in Mouse and Macaque. Hum Gene Ther 2019; 30:571-589. [PMID: 30358434 PMCID: PMC6534089 DOI: 10.1089/hum.2018.193] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 10/23/2018] [Indexed: 12/15/2022] Open
Abstract
Mutations in GUCY2D, the gene encoding retinal guanylate cyclase-1 (retGC1), are the leading cause of autosomal dominant cone-rod dystrophy (CORD6). Significant progress toward clinical application of gene replacement therapy for Leber congenital amaurosis (LCA) due to recessive mutations in GUCY2D (LCA1) has been made, but a different approach is needed to treat CORD6 where gain of function mutations cause dysfunction and dystrophy. The CRISPR/Cas9 gene editing system efficiently disrupts genes at desired loci, enabling complete gene knockout or homology directed repair. Here, adeno-associated virus (AAV)-delivered CRISPR/Cas9 was used specifically to edit/disrupt this gene's early coding sequence in mouse and macaque photoreceptors in vivo, thereby knocking out retGC1 expression and demonstrably altering retinal function and structure. Neither preexisting nor induced Cas9-specific T-cell responses resulted in ocular inflammation in macaques, nor did it limit GUCY2D editing. The results show, for the first time, the ability to perform somatic gene editing in primates using AAV-CRISPR/Cas9 and demonstrate the viability this approach for treating inherited retinal diseases in general and CORD6 in particular.
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Affiliation(s)
| | - Sanford L. Boye
- Department of Ophthalmology, University of Florida, Gainesville, Florida
| | - Diego Fajardo
- Department of Ophthalmology, University of Florida, Gainesville, Florida
| | - Kaitlyn Calabro
- Department of Ophthalmology, University of Florida, Gainesville, Florida
| | - James J. Peterson
- Department of Ophthalmology, University of Florida, Gainesville, Florida
| | - Christianne E. Strang
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Dibyendu Chakraborty
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama
| | | | | | | | | | | | - Paul D. Gamlin
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Shannon E. Boye
- Department of Ophthalmology, University of Florida, Gainesville, Florida
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10
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Sinha T, Makia M, Du J, Naash MI, Al-Ubaidi MR. Flavin homeostasis in the mouse retina during aging and degeneration. J Nutr Biochem 2018; 62:123-133. [PMID: 30290331 PMCID: PMC7162609 DOI: 10.1016/j.jnutbio.2018.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/31/2018] [Accepted: 09/01/2018] [Indexed: 12/14/2022]
Abstract
Involvement of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) in cellular homeostasis has been well established for tissues other than the retina. Here, we present an optimized method to effectively extract and quantify FAD and FMN from a single neural retina and its corresponding retinal pigment epithelium (RPE). Optimizations led to detection efficiency of 0.1 pmol for FAD and FMN while 0.01 pmol for riboflavin. Interestingly, levels of FAD and FMN in the RPE were found to be 1.7- and 12.5-fold higher than their levels in the retina, respectively. Both FAD and FMN levels in the RPE and retina gradually decline with age and preceded the age-dependent drop in the functional competence of the retina as measured by electroretinography. Further, quantifications of retinal levels of FAD and FMN in different mouse models of retinal degeneration revealed differential metabolic requirements of these two factors in relation to the rate and degree of photoreceptor degeneration. We also found twofold reductions in retinal levels of FAD and FMN in two mouse models of diabetic retinopathy. Altogether, our results suggest that retinal levels of FAD and FMN can be used as potential markers to determine state of health of the retina in general and more specifically the photoreceptors.
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Affiliation(s)
- Tirthankar Sinha
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204
| | - Mustafa Makia
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204
| | - Jianhai Du
- Department of Ophthalmology and Department of Biochemistry, West Virginia University, Morgantown, WV 26506
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204.
| | - Muayyad R Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204.
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11
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Zaneveld SA, Eblimit A, Liang Q, Bertrand R, Wu N, Liu H, Nguyen Q, Zaneveld J, Wang K, Li Y, Chen R. Gene Therapy Rescues Retinal Degeneration in Receptor Expression-Enhancing Protein 6 Mutant Mice. Hum Gene Ther 2018; 30:302-315. [PMID: 30101608 PMCID: PMC6437630 DOI: 10.1089/hum.2018.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hereditary retinal dystrophy is clinically defined as a broad group of chronic and progressive disorders that affect visual function by causing photoreceptor degeneration. Previously, we identified mutations in the gene encoding receptor expression-enhancing protein 6 (REEP6), in individuals with autosomal recessive retinitis pigmentosa (RP), the most common form of inherited retinal dystrophy. One individual was molecularly diagnosed with biallelic REEP6 mutations, a missense mutation over a frameshift mutation. In this study, we generated Reep6 compound heterozygous mice, Reep6L135P/-, which mimic the patient genotype and recapitulate the early-onset retinal degeneration phenotypes observed in the individual with RP. To determine the feasibility of rescuing the Reep6 mutant phenotype via gene replacement therapy, we delivered Reep6.1, the mouse retina-specific isoform of REEP6, to photoreceptors of Reep6 mutant mice on postnatal day 20. Evaluation of the therapeutic effects 2 months posttreatment showed improvements in the photoresponse as well as preservation of photoreceptor cells. Importantly, guanylyl cyclase 1 (GC1) expression was also restored to the outer segment after treatment. Furthermore, rAAV8-Reep6.1 single treatment in Reep6 mutant mice 1 year postinjection showed significant improvements in retinal function and morphology, suggesting that the treatment is effective even after a prolonged period. Findings from this study show that gene replacement therapy in the retina with rAAV overexpressing Reep6 is effective, preserving photoreceptor function in Reep6 mutant mice. These findings provide evidence that rAAV8-based gene therapy can prolong survival of photoreceptors in vivo and can be potentially used as a therapeutic modality for treatment of patients with RP.
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Affiliation(s)
- Smriti Agrawal Zaneveld
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Aiden Eblimit
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Qingnan Liang
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,3 Department of Biochemistry, Baylor College of Medicine, Houston, TX
| | - Renae Bertrand
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,3 Department of Biochemistry, Baylor College of Medicine, Houston, TX
| | - Nathaniel Wu
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Hehe Liu
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Quynh Nguyen
- 3 Department of Biochemistry, Baylor College of Medicine, Houston, TX
| | - Jacques Zaneveld
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Keqing Wang
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Yumei Li
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Rui Chen
- 1 Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX.,2 Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
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12
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Wimberg H, Lev D, Yosovich K, Namburi P, Banin E, Sharon D, Koch KW. Photoreceptor Guanylate Cyclase ( GUCY2D) Mutations Cause Retinal Dystrophies by Severe Malfunction of Ca 2+-Dependent Cyclic GMP Synthesis. Front Mol Neurosci 2018; 11:348. [PMID: 30319355 PMCID: PMC6167591 DOI: 10.3389/fnmol.2018.00348] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/06/2018] [Indexed: 12/12/2022] Open
Abstract
Over 100 mutations in GUCY2D that encodes the photoreceptor guanylate cyclase GC-E are known to cause two major diseases: autosomal recessive Leber congenital amaurosis (arLCA) or autosomal dominant cone-rod dystrophy (adCRD) with a poorly understood mechanism at the molecular level in most cases. Only few mutations were further characterized for their enzymatic and molecular properties. GC-E activity is under control of neuronal Ca2+-sensor proteins, which is often a possible route to dysfunction. We investigated five recently-identified GC-E mutants that have been reported in patients suffering from arLCA (one large family) and adCRD/maculopathy (four families). Microsatellite analysis revealed that one of the mutations, c.2538G > C (p.K846N), occurred de novo. To better understand the mechanism by which mutations that are located in different GC-E domains develop different phenotypes, we investigated the molecular consequences of these mutations by expressing wildtype and mutant GC-E variants in HEK293 cells. Analyzing their general enzymatic behavior, their regulation by Ca2+ sensor proteins and retinal degeneration protein 3 (RD3) dimerization domain mutants (p.E841K and p.K846N) showed a shift in Ca2+-sensitive regulation by guanylate cyclase-activating proteins (GCAPs). Mutations in the cyclase catalytic domain led to a loss of enzyme function in the mutant p.P873R, but not in p.V902L. Instead, the p.V902L mutation increased the guanylate cyclase activity more than 20-fold showing a high GCAP independent activity and leading to a constitutively active mutant. This is the first mutation to be described affecting the GC-E catalytic core in a complete opposite way.
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Affiliation(s)
- Hanna Wimberg
- Department of Neuroscience, Biochemistry Group, University of Oldenburg, Oldenburg, Germany
| | - Dorit Lev
- The Rina Mor Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Keren Yosovich
- The Rina Mor Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel.,Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Prasanthi Namburi
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Karl-Wilhelm Koch
- Department of Neuroscience, Biochemistry Group, University of Oldenburg, Oldenburg, Germany
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13
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Duncan JL, Pierce EA, Laster AM, Daiger SP, Birch DG, Ash JD, Iannaccone A, Flannery JG, Sahel JA, Zack DJ, Zarbin MA. Inherited Retinal Degenerations: Current Landscape and Knowledge Gaps. Transl Vis Sci Technol 2018; 7:6. [PMID: 30034950 PMCID: PMC6052953 DOI: 10.1167/tvst.7.4.6] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/28/2018] [Indexed: 12/11/2022] Open
Affiliation(s)
- Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Amy M Laster
- Foundation Fighting Blindness, Columbia, MD, USA
| | - Stephen P Daiger
- Human Genetics Center, School of Public Health, and Ruiz Department of Ophthalmology and Visual Science, The University of Texas Health Science Center, Houston, TX, USA
| | - David G Birch
- Rose-Silverthorne Retinal Degenerations Laboratory, Retina Foundation of the Southwest, Dallas, TX, USA
| | - John D Ash
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Alessandro Iannaccone
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - John G Flannery
- Vision Science, the Helen Wills Neuroscience Institute, the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - José A Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Institut de la Vision-Sorbonne Université, Inserm, CNRS-Paris, France
| | - Donald J Zack
- Departments of Ophthalmology, Neuroscience, Molecular Biology and Genetics, and Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marco A Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers-New Jersey Medical School, Rutgers University, Newark, NJ, USA
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14
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Carvalho LS, Xiao R, Wassmer SJ, Langsdorf A, Zinn E, Pacouret S, Shah S, Comander JI, Kim LA, Lim L, Vandenberghe LH. Synthetic Adeno-Associated Viral Vector Efficiently Targets Mouse and Nonhuman Primate Retina In Vivo. Hum Gene Ther 2018; 29:771-784. [PMID: 29325457 DOI: 10.1089/hum.2017.154] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gene therapy is a promising approach in the treatment of inherited and common complex disorders of the retina. Preclinical and clinical studies have validated the use of adeno-associated viral vectors (AAV) as a safe and efficient delivery vehicle for gene transfer. Retinal pigment epithelium and rods-and to a lesser extent, cone photoreceptors-can be efficiently targeted with AAV. Other retinal cell types however are more challenging targets. The aim of this study was to characterize the transduction profile and efficiency of in silico designed, synthetic Anc80 AAVs for retinal gene transfer. Three Anc80 variants were evaluated for retinal targeting in mice and primates following subretinal delivery. In the murine retina Anc80L65 demonstrated high level of retinal pigment epithelium and photoreceptor targeting with comparable cone photoreceptor affinity compared to other AAVs. Remarkably, Anc80L65 enhanced transduction kinetics with visible expression as early as day 1 and steady state mRNA levels at day 3. Inner retinal tropism of Anc80 variants demonstrated distinct transduction patterns of Müller glia, retinal ganglion cells and inner nuclear layer neurons. Finally, murine findings with Anc80L65 qualitatively translated to the Rhesus macaque in terms of cell targets, levels and onset of expression. Our findings support the use of Anc80L65 for therapeutic subretinal gene delivery.
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Affiliation(s)
- Livia S Carvalho
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Ru Xiao
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Sarah J Wassmer
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Aliete Langsdorf
- 2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Eric Zinn
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Simon Pacouret
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,6 INSERM UMR 1089, University of Nantes, Nantes University Hospital , Nantes, France
| | - Samiksha Shah
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Jason I Comander
- 2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Leo A Kim
- 3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Laurence Lim
- 4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Luk H Vandenberghe
- 1 Grousbeck Gene Therapy Center, Boston, Massachusetts.,2 Ocular Genomics Institute , Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,3 Schepens Eye Research Institute, Boston, Massachusetts.,4 Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,5 Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts
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15
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Sharon D, Wimberg H, Kinarty Y, Koch KW. Genotype-functional-phenotype correlations in photoreceptor guanylate cyclase (GC-E) encoded by GUCY2D. Prog Retin Eye Res 2018; 63:69-91. [DOI: 10.1016/j.preteyeres.2017.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/16/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
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16
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Kumaran N, Smith AJ, Michaelides M, Ali R, Bainbridge J. Gene therapy for Leber congenital amaurosis. EXPERT REVIEW OF OPHTHALMOLOGY 2018. [DOI: 10.1080/17469899.2018.1429916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Neruban Kumaran
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Alexander J. Smith
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - Robin Ali
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
| | - James Bainbridge
- NIHR Biomedical Research Centre for Ophthalmology, UCL and Moorfields Eye Hospital, London, UK
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17
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Hanlon KS, Chadderton N, Palfi A, Blanco Fernandez A, Humphries P, Kenna PF, Millington-Ward S, Farrar GJ. A Novel Retinal Ganglion Cell Promoter for Utility in AAV Vectors. Front Neurosci 2017; 11:521. [PMID: 28983234 PMCID: PMC5613148 DOI: 10.3389/fnins.2017.00521] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 09/04/2017] [Indexed: 12/13/2022] Open
Abstract
Significant advances in gene therapy have enabled exploration of therapies for inherited retinal disorders, many of which are in preclinical development or clinical evaluation. Gene therapy for retinal conditions has led the way in this growing field. The loss of retinal ganglion cells (RGCs) is a hallmark of a number of retinal disorders. As the field matures innovations that aid in refining therapies and optimizing efficacy are in demand. Gene therapies under development for RGC-related disorders, when delivered with recombinant adeno associated vectors (AAV), have typically been expressed from ubiquitous promoter sequences. Here we describe how a novel promoter from the murine Nefh gene was selected to drive transgene expression in RGCs. The Nefh promoter, in an AAV2/2 vector, was shown to drive preferential EGFP expression in murine RGCs in vivo following intravitreal injection. In contrast, EGFP expression from a CMV promoter was observed not only in RGCs, but throughout the inner nuclear layer and in amacrine cells located within the ganglion cell layer (GCL). Of note, the Nefh promoter sequence is sufficiently compact to be readily accommodated in AAV vectors, where transgene size represents a significant constraint. Moreover, this promoter should in principle provide a more targeted and potentially safer alternative for RGC-directed gene therapies.
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Affiliation(s)
- Killian S Hanlon
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - Naomi Chadderton
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - Arpad Palfi
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | | | - Peter Humphries
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - Paul F Kenna
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland.,Research Foundation, Royal Victoria Eye and Ear HospitalDublin, Ireland
| | - Sophia Millington-Ward
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - G Jane Farrar
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
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18
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Affiliation(s)
- Arthur Planul
- Inserm, Institut de la Vision, UMR S968, 75012 Paris, France;,
- Sorbonne Universités, UPMC Université Paris 6, UMR S968, 75012 Paris, France
- CNRS, UMR 7210, 75012 Paris, France
| | - Deniz Dalkara
- Inserm, Institut de la Vision, UMR S968, 75012 Paris, France;,
- Sorbonne Universités, UPMC Université Paris 6, UMR S968, 75012 Paris, France
- CNRS, UMR 7210, 75012 Paris, France
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19
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Kumaran N, Moore AT, Weleber RG, Michaelides M. Leber congenital amaurosis/early-onset severe retinal dystrophy: clinical features, molecular genetics and therapeutic interventions. Br J Ophthalmol 2017; 101:1147-1154. [PMID: 28689169 PMCID: PMC5574398 DOI: 10.1136/bjophthalmol-2016-309975] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/26/2017] [Accepted: 04/30/2017] [Indexed: 12/29/2022]
Abstract
Leber congenital amaurosis (LCA) and early-onset severe retinal dystrophy (EOSRD) are both genetically and phenotypically heterogeneous, and characterised clinically by severe congenital/early infancy visual loss, nystagmus, amaurotic pupils and markedly reduced/absent full-field electroretinograms. The vast genetic heterogeneity of inherited retinal disease has been established over the last 10 - 20 years, with disease-causing variants identified in 25 genes to date associated with LCA/EOSRD, accounting for 70–80% of cases, with thereby more genes yet to be identified. There is now far greater understanding of the structural and functional associations seen in the various LCA/EOSRD genotypes. Subsequent development/characterisation of LCA/EOSRD animal models has shed light on the underlying pathogenesis and allowed the demonstration of successful rescue with gene replacement therapy and pharmacological intervention in multiple models. These advancements have culminated in more than 12 completed, ongoing and anticipated phase I/II and phase III gene therapy and pharmacological human clinical trials. This review describes the clinical and genetic characteristics of LCA/EOSRD and the differential diagnoses to be considered. We discuss in further detail the diagnostic clinical features, pathophysiology, animal models and human treatment studies and trials, in the more common genetic subtypes and/or those closest to intervention.
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Affiliation(s)
- Neruban Kumaran
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,University of California San Francisco, San Francisco CA, California, USA
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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20
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Aguirre GK, Butt OH, Datta R, Roman AJ, Sumaroka A, Schwartz SB, Cideciyan AV, Jacobson SG. Postretinal Structure and Function in Severe Congenital Photoreceptor Blindness Caused by Mutations in the GUCY2D Gene. Invest Ophthalmol Vis Sci 2017; 58:959-973. [PMID: 28403437 PMCID: PMC5308769 DOI: 10.1167/iovs.16-20413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Purpose To examine how severe congenital blindness resulting from mutations of the GUCY2D gene alters brain structure and function, and to relate these findings to the notable preservation of retinal architecture in this form of Leber congenital amaurosis (LCA). Methods Six GUCY2D-LCA patients (ages 20–46) were studied with optical coherence tomography of the retina and multimodal magnetic resonance imaging (MRI) of the brain. Measurements from this group were compared to those obtained from populations of normally sighted controls and people with congenital blindness of a variety of causes. Results Patients with GUCY2D-LCA had preservation of the photoreceptors, ganglion cells, and nerve fiber layer. Despite this, visual function in these patients ranged from 20/160 acuity to no light perception, and functional MRI responses to light stimulation were attenuated and restricted. This severe visual impairment was reflected in substantial thickening of the gray matter layer of area V1, accompanied by an alteration of resting-state correlations within the occipital lobe, similar to a comparison group of congenitally blind people with structural damage to the retina. In contrast to the comparison blind population, however, the GUCY2D-LCA group had preservation of the size of the optic chiasm, and the fractional anisotropy of the optic radiations as measured with diffusion tensor imaging was also normal. Conclusions These results identify dissociable effects of blindness upon the visual pathway. Further, the relatively intact postgeniculate white matter pathway in GUCY2D-LCA is encouraging for the prospect of recovery of visual function with gene augmentation therapy.
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Affiliation(s)
- Geoffrey K Aguirre
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Omar H Butt
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Ritobrato Datta
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alejandro J Roman
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alexander Sumaroka
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Sharon B Schwartz
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Artur V Cideciyan
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Samuel G Jacobson
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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21
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Boye SL, Olshevskaya EV, Peshenko IV, McCullough KT, Boye SE, Dizhoor AM. Functional study of two biochemically unusual mutations in GUCY2D Leber congenital amaurosis expressed via adenoassociated virus vector in mouse retinas. Mol Vis 2016; 22:1342-1351. [PMID: 27881908 PMCID: PMC5108460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/08/2016] [Indexed: 11/03/2022] Open
Abstract
PURPOSE To test, in living photoreceptors, two mutations, S248W and R1091x, in the GUCY2D gene linked to Leber congenital amaurosis 1 (LCA1) that fail to inactivate the catalytic activity of a heterologously expressed retinal membrane guanylyl cyclase 1 (RetGC1). METHODS GUC2YD cDNA constructs coding for wild-type human (hWT), R1091x, and S248W GUCY2D under the control of the human rhodopsin kinase promoter were expressed in Gucy2e-/-Gucy2f-/- knockout (GCdKO) mouse retinas, which lack endogenous RetGC activity. The constructs were delivered via subretinally injected adenoassociated virus (AAV) vector in one eye, leaving the opposite eye as the non-injected negative control. After testing with electroretinography (ERG), the retinas extracted from the AAV-treated and control eyes were used in guanylyl cyclase activity assays, immunoblotting, and anti-RetGC1 immunofluorescence staining. RESULTS Cyclase activity in retinas treated with either hWT or R1091x GUCY2D transgenes was similar but was undetectable in the S248W GUCY2D-treated retinas, which starkly contrasts their relative activities when heterologously expressed in human embryonic kidney (HEK293) cells. Rod and cone ERGs, absent in GCdKO, appeared in the hWT and R1091x GUCY2D-injected eyes, while the S248W mutant failed to restore scotopic ERG response and enabled only rudimentary photopic ERG response. The hWT and R1091x GUCY2D immunofluorescence was robust in the rod and cone outer segments, whereas the S248W was detectable only in the sparse cone outer segments and sporadic photoreceptor cell bodies. Robust RetGC1 expression was detected with immunoblotting in the hWT and R1091x-treated retinas but was marginal at best in the S248W GUCY2D retinas, despite the confirmed presence of the S248W GUCY2D transcripts. CONCLUSIONS The phenotype of S248W GUCY2D in living retinas did not correlate with the previously described normal biochemical activity of this mutant when heterologously expressed in non-photoreceptor cell culture. This result suggests that the S248W mutation contributes to LCA1 by hampering the expression, processing, and/or cellular transport of GUCY2D, rather than its enzymatic properties. In contrast, the effective restoration of rod and cone function by R1091x GUCY2D is paradoxical and does not explain the severe loss of vision typical for LCA1 associated with that mutant allele.
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Affiliation(s)
- Sanford L. Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL
| | | | - Igor V. Peshenko
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA
| | | | - Shannon E. Boye
- Department of Ophthalmology, University of Florida, Gainesville, FL
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22
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Sengillo JD, Justus S, Tsai YT, Cabral T, Tsang SH. Gene and cell-based therapies for inherited retinal disorders: An update. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2016; 172:349-366. [PMID: 27862925 DOI: 10.1002/ajmg.c.31534] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Retinal degenerations present a unique challenge as disease progression is irreversible and the retina has little regenerative potential. No current treatments for inherited retinal disease have the ability to reverse blindness, and current dietary supplement recommendations only delay disease progression with varied results. However, the retina is anatomically accessible and capable of being monitored at high resolution in vivo. This, in addition to the immune-privileged status of the eye, has put ocular disease at the forefront of advances in gene- and cell-based therapies. This review provides an update on gene therapies and randomized control trials for inherited retinal disease, including Leber congenital amaurosis, choroideremia, retinitis pigmentosa, Usher syndrome, X-linked retinoschisis, Leber hereditary optic neuropathy, and achromatopsia. New gene-modifying and cell-based strategies are also discussed. © 2016 Wiley Periodicals, Inc.
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23
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Dizhoor AM, Olshevskaya EV, Peshenko IV. The R838S Mutation in Retinal Guanylyl Cyclase 1 (RetGC1) Alters Calcium Sensitivity of cGMP Synthesis in the Retina and Causes Blindness in Transgenic Mice. J Biol Chem 2016; 291:24504-24516. [PMID: 27703005 DOI: 10.1074/jbc.m116.755553] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/03/2016] [Indexed: 11/06/2022] Open
Abstract
Substitutions of Arg838 in the dimerization domain of a human retinal membrane guanylyl cyclase 1 (RetGC1) linked to autosomal dominant cone-rod degeneration type 6 (CORD6) change RetGC1 regulation in vitro by Ca2+ In addition, we find that R838S substitution makes RetGC1 less sensitive to inhibition by retinal degeneration-3 protein (RD3). We selectively expressed human R838S RetGC1 in mouse rods and documented the decline in rod vision and rod survival. To verify that changes in rods were specifically caused by the CORD6 mutation, we used for comparison cones, which in the same mice did not express R838S RetGC1 from the transgenic construct. The R838S RetGC1 expression in rod outer segments reduced inhibition of cGMP production in the transgenic mouse retinas at the free calcium concentrations typical for dark-adapted rods. The transgenic mice demonstrated early-onset and rapidly progressed with age decline in visual responses from the targeted rods, in contrast to the longer lasting preservation of function in the non-targeted cones. The decline in rod function in the retina resulted from a progressive degeneration of rods between 1 and 6 months of age, with the severity and pace of the degeneration consistent with the extent to which the Ca2+ sensitivity of the retinal cGMP production was affected. Our study presents a new experimental model for exploring cellular mechanisms of the CORD6-related photoreceptor death. This mouse model provides the first direct biochemical and physiological in vivo evidence for the Arg838 substitutions in RetGC1 being the culprit behind the pathogenesis of the CORD6 congenital blindness.
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Affiliation(s)
- Alexander M Dizhoor
- From the Department of Research, Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027.
| | - Elena V Olshevskaya
- From the Department of Research, Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
| | - Igor V Peshenko
- From the Department of Research, Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania 19027
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24
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Abstract
Over the last few years, huge progress has been made with regard to the understanding of molecular mechanisms underlying the pathogenesis of neurodegenerative diseases of the eye. Such knowledge has led to the development of gene therapy approaches to treat these devastating disorders. Challenges regarding the efficacy and efficiency of therapeutic gene delivery have driven the development of novel therapeutic approaches, which continue to evolve the field of ocular gene therapy. In this review article, we will discuss the evolution of preclinical and clinical strategies that have improved gene therapy in the eye, showing that treatment of vision loss has a bright future.
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Affiliation(s)
- Lolita Petit
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Hemant Khanna
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts.,2 Department of Neurobiology, University of Massachusetts Medical School , Worcester, Massachusetts
| | - Claudio Punzo
- 1 Department of Ophthalmology and Gene Therapy Center, University of Massachusetts Medical School , Worcester, Massachusetts.,2 Department of Neurobiology, University of Massachusetts Medical School , Worcester, Massachusetts
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25
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Dinculescu A, Stupay RM, Deng WT, Dyka FM, Min SH, Boye SL, Chiodo VA, Abrahan CE, Zhu P, Li Q, Strettoi E, Novelli E, Nagel-Wolfrum K, Wolfrum U, Smith WC, Hauswirth WW. AAV-Mediated Clarin-1 Expression in the Mouse Retina: Implications for USH3A Gene Therapy. PLoS One 2016; 11:e0148874. [PMID: 26881841 PMCID: PMC4755610 DOI: 10.1371/journal.pone.0148874] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Accepted: 01/23/2016] [Indexed: 02/07/2023] Open
Abstract
Usher syndrome type III (USH3A) is an autosomal recessive disorder caused by mutations in clarin-1 (CLRN1) gene, leading to progressive retinal degeneration and sensorineural deafness. Efforts to develop therapies for preventing photoreceptor cell loss are hampered by the lack of a retinal phenotype in the existing USH3 mouse models and by conflicting reports regarding the endogenous retinal localization of clarin-1, a transmembrane protein of unknown function. In this study, we used an AAV-based approach to express CLRN1 in the mouse retina in order to determine the pattern of its subcellular localization in different cell types. We found that all major classes of retinal cells express AAV-delivered CLRN1 driven by the ubiquitous, constitutive small chicken β-actin promoter, which has important implications for the design of future USH3 gene therapy studies. Within photoreceptor cells, AAV-expressed CLRN1 is mainly localized at the inner segment region and outer plexiform layer, similar to the endogenous expression of other usher proteins. Subretinal delivery using a full strength viral titer led to significant loss of retinal function as evidenced by ERG analysis, suggesting that there is a critical limit for CLRN1 expression in photoreceptor cells. Taken together, these results suggest that CLRN1 expression is potentially supported by a variety of retinal cells, and the right combination of AAV vector dose, promoter, and delivery method needs to be selected to develop safe therapies for USH3 disorder.
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Affiliation(s)
- Astra Dinculescu
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
- * E-mail:
| | - Rachel M. Stupay
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Wen-Tao Deng
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Frank M. Dyka
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Seok-Hong Min
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Sanford L. Boye
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Vince A. Chiodo
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Carolina E. Abrahan
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Ping Zhu
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | - Qiuhong Li
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
| | | | | | - Kerstin Nagel-Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | - W. Clay Smith
- Ophthalmology, University of Florida, Gainesville, FL, United States of America
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Dalkara D, Goureau O, Marazova K, Sahel JA. Let There Be Light: Gene and Cell Therapy for Blindness. Hum Gene Ther 2016; 27:134-47. [PMID: 26751519 PMCID: PMC4779297 DOI: 10.1089/hum.2015.147] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/06/2016] [Indexed: 12/14/2022] Open
Abstract
Retinal degenerative diseases are a leading cause of irreversible blindness. Retinal cell death is the main cause of vision loss in genetic disorders such as retinitis pigmentosa, Stargardt disease, and Leber congenital amaurosis, as well as in complex age-related diseases such as age-related macular degeneration. For these blinding conditions, gene and cell therapy approaches offer therapeutic intervention at various disease stages. The present review outlines advances in therapies for retinal degenerative disease, focusing on the progress and challenges in the development and clinical translation of gene and cell therapies. A significant body of preclinical evidence and initial clinical results pave the way for further development of these cutting edge treatments for patients with retinal degenerative disorders.
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Affiliation(s)
- Deniz Dalkara
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
| | - Olivier Goureau
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
| | - Katia Marazova
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, France
- Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
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27
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A Mini-review: Animal Models of GUCY2D Leber Congenital Amaurosis (LCA1). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:253-8. [PMID: 26427419 DOI: 10.1007/978-3-319-17121-0_34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
GUCY2D encodes retinal guanylate cylase-1 (retGC1), a protein that plays a pivotal role in the recovery phase of phototransduction. Mutations in GUCY2D are associated with a leading cause of recessive Leber congenital amaurosis (LCA1). Patients present within the first year of life with aberrant or unrecordable electroretinogram (ERG), nystagmus and a relatively normal fundus. Aside from abnormalities in the outer segments of foveal cones and, in some patients, foveal cone loss, LCA1 patients retain normal retinal laminar architecture suggesting they may be good candidates for gene replacement therapy. Several animal models of LCA1, both naturally occurring and engineered, have been characterized and provide valuable tools for translational studies. This mini-review will summarize the phenotypes of these models and describe how each has been instrumental in proof of concept studies to develop a gene replacement therapy for GUCY2D-LCA1.
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28
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Kostic C, Arsenijevic Y. Animal modelling for inherited central vision loss. J Pathol 2015; 238:300-10. [PMID: 26387748 PMCID: PMC5063185 DOI: 10.1002/path.4641] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/02/2015] [Accepted: 09/16/2015] [Indexed: 01/01/2023]
Abstract
Disease-causing variants of a large number of genes trigger inherited retinal degeneration leading to photoreceptor loss. Because cones are essential for daylight and central vision such as reading, mobility, and face recognition, this review focuses on a variety of animal models for cone diseases. The pertinence of using these models to reveal genotype/phenotype correlations and to evaluate new therapeutic strategies is discussed. Interestingly, several large animal models recapitulate human diseases and can serve as a strong base from which to study the biology of disease and to assess the scale-up of new therapies. Examples of innovative approaches will be presented such as lentiviral-based transgenesis in pigs and adeno-associated virus (AAV)-gene transfer into the monkey eye to investigate the neural circuitry plasticity of the visual system. The models reported herein permit the exploration of common mechanisms that exist between different species and the identification and highlighting of pathways that may be specific to primates, including humans.
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Affiliation(s)
- Corinne Kostic
- Unit of Gene Therapy and Stem Cell Biology, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Switzerland
| | - Yvan Arsenijevic
- Unit of Gene Therapy and Stem Cell Biology, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Switzerland
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29
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Veleri S, Lazar CH, Chang B, Sieving PA, Banin E, Swaroop A. Biology and therapy of inherited retinal degenerative disease: insights from mouse models. Dis Model Mech 2015; 8:109-29. [PMID: 25650393 PMCID: PMC4314777 DOI: 10.1242/dmm.017913] [Citation(s) in RCA: 177] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases.
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Affiliation(s)
- Shobi Veleri
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Csilla H Lazar
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA. Molecular Biology Center, Interdisciplinary Research Institute on Bio-Nano Sciences, Babes-Bolyai-University, Cluj-Napoca, 400271, Romania
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eyal Banin
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA. Center for Retinal and Macular Degenerations, Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Anand Swaroop
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Scalabrino ML, Boye SL, Fransen KMH, Noel JM, Dyka FM, Min SH, Ruan Q, De Leeuw CN, Simpson EM, Gregg RG, McCall MA, Peachey NS, Boye SE. Intravitreal delivery of a novel AAV vector targets ON bipolar cells and restores visual function in a mouse model of complete congenital stationary night blindness. Hum Mol Genet 2015; 24:6229-39. [PMID: 26310623 DOI: 10.1093/hmg/ddv341] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/17/2015] [Indexed: 11/13/2022] Open
Abstract
Adeno-associated virus (AAV) effectively targets therapeutic genes to photoreceptors, pigment epithelia, Müller glia and ganglion cells of the retina. To date, no one has shown the ability to correct, with gene replacement, an inherent defect in bipolar cells (BCs), the excitatory interneurons of the retina. Targeting BCs with gene replacement has been difficult primarily due to the relative inaccessibility of BCs to standard AAV vectors. This approach would be useful for restoration of vision in patients with complete congenital stationary night blindness (CSNB1), where signaling through the ON BCs is eliminated due to mutations in their G-protein-coupled cascade genes. For example, the majority of CSNB1 patients carry a mutation in nyctalopin (NYX), which encodes a protein essential for proper localization of the TRPM1 cation channel required for ON BC light-evoked depolarization. As a group, CSNB1 patients have a normal electroretinogram (ERG) a-wave, indicative of photoreceptor function, but lack a b-wave due to defects in ON BC signaling. Despite retinal dysfunction, the retinas of CSNB1 patients do not degenerate. The Nyx(nob) mouse model of CSNB1 faithfully mimics this phenotype. Here, we show that intravitreally injected, rationally designed AAV2(quadY-F+T-V) containing a novel 'Ple155' promoter drives either GFP or YFP_Nyx in postnatal Nyx(nob) mice. In treated Nyx(nob) retina, robust and targeted Nyx transgene expression in ON BCs partially restored the ERG b-wave and, at the cellular level, signaling in ON BCs. Our results support the potential for gene delivery to BCs and gene replacement therapy in human CSNB1.
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Affiliation(s)
| | | | | | | | | | | | | | - Charles N De Leeuw
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and Therapeutics at the Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Ronald G Gregg
- Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202, USA
| | - Maureen A McCall
- Department of Ophthalmology and Visual Sciences, Department of Anatomical Sciences and Neurobiology and
| | - Neal S Peachey
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA, Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA and Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Shannon E Boye
- Department of Ophthalmology and, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL 32610, USA,
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Boye SL, Peterson JJ, Choudhury S, Min SH, Ruan Q, McCullough KT, Zhang Z, Olshevskaya EV, Peshenko IV, Hauswirth WW, Ding XQ, Dizhoor AM, Boye SE. Gene Therapy Fully Restores Vision to the All-Cone Nrl(-/-) Gucy2e(-/-) Mouse Model of Leber Congenital Amaurosis-1. Hum Gene Ther 2015; 26:575-92. [PMID: 26247368 DOI: 10.1089/hum.2015.053] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mutations in GUCY2D are the cause of Leber congenital amaurosis type 1 (LCA1). GUCY2D encodes retinal guanylate cyclase-1 (retGC1), a protein expressed exclusively in outer segments of photoreceptors and essential for timely recovery from photoexcitation. Recent clinical data show that, despite a high degree of visual disturbance stemming from a loss of cone function, LCA1 patients retain normal photoreceptor architecture, except for foveal cone outer segment abnormalities and, in some patients, foveal cone loss. These results point to the cone-rich central retina as a target for GUCY2D replacement. LCA1 gene replacement studies thus far have been conducted in rod-dominant models (mouse) or with vectors and organisms lacking clinical translatability. Here we investigate gene replacement in the Nrl(-/-) Gucy2e(-/-) mouse, an all-cone model deficient in retGC1. We show that AAV-retGC1 treatment fully restores cone function, cone-mediated visual behavior, and guanylate cyclase activity, and preserves cones in treated Nrl(-/-) Gucy2e(-/-) mice over the long-term. A novel finding was that retinal function could be restored to levels above that in Nrl(-/-) controls, contrasting results in other models of retGC1 deficiency. We attribute this to increased cyclase activity in treated Nrl(-/-) Gucy2e(-/-) mice relative to Nrl(-/-) controls. Thus, Nrl(-/-) Gucy2e(-/-) mice possess an expanded dynamic range in ERG response to gene replacement relative to other models. Lastly, we show that a candidate clinical vector, AAV5-GRK1-GUCY2D, when delivered to adult Nrl(-/-) Gucy2e(-/-) mice, restores retinal function that persists for at least 6 months. Our results provide strong support for clinical application of a gene therapy targeted to the cone-rich, central retina of LCA1 patients.
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Affiliation(s)
- Sanford L Boye
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - James J Peterson
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Shreyasi Choudhury
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Seok Hong Min
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Qing Ruan
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - K Tyler McCullough
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Zhonghong Zhang
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Elena V Olshevskaya
- 2 Department of Basic Sciences Research, Salus University , Elkins Park, Pennsylvania
| | - Igor V Peshenko
- 2 Department of Basic Sciences Research, Salus University , Elkins Park, Pennsylvania
| | - William W Hauswirth
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Xi-Qin Ding
- 3 Department of Cell Biology, College of Medicine, University of Oklahoma , Oklahoma City, Oklahoma
| | - Alexander M Dizhoor
- 2 Department of Basic Sciences Research, Salus University , Elkins Park, Pennsylvania
| | - Shannon E Boye
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
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32
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Psychophysical testing in rodent models of glaucomatous optic neuropathy. Exp Eye Res 2015; 141:154-63. [PMID: 26144667 DOI: 10.1016/j.exer.2015.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/08/2015] [Accepted: 06/29/2015] [Indexed: 12/14/2022]
Abstract
Processing of visual information begins in the retina, with photoreceptors converting light stimuli into neural signals. Ultimately, signals are transmitted to the brain through signaling networks formed by interneurons, namely bipolar, horizontal and amacrine cells providing input to retinal ganglion cells (RGCs), which form the optic nerve with their axons. As part of the chronic nature of glaucomatous optic neuropathy, the increasing and irreversible damage and ultimately loss of neurons, RGCs in particular, occurs following progressive damage to the optic nerve head (ONH), eventually resulting in visual impairment and visual field loss. There are two behavioral assays that are typically used to assess visual deficits in glaucoma rodent models, the visual water task and the optokinetic drum. The visual water task can assess an animal's ability to distinguish grating patterns that are associated with an escape from water. The optokinetic drum relies on the optomotor response, a reflex turning of the head and neck in the direction of the visual stimuli, which usually consists of rotating black and white gratings. This reflex is a physiological response critical for keeping the image stable on the retina. Driven initially by the neuronal input from direction-selective RGCs, this reflex is comprised of a number of critical sensory and motor elements. In the presence of repeatable and defined stimuli, this reflex is extremely well suited to analyze subtle changes in the circuitry and performance of retinal neurons. Increasing the cycles of these alternating gratings per degree, or gradually reducing the contrast of the visual stimuli, threshold levels can be determined at which the animal is no longer tracking the stimuli, and thereby visual function of the animal can be determined non-invasively. Integrating these assays into an array of outcome measures that determine multiple aspects of visual function is a central goal in vision research and can be realized, for example, by the combination of measuring optomotor reflex function with electroretinograms (ERGs) and optical coherence tomography (OCT) of the retina. These structure-function correlations in vivo are urgently needed to identify disease mechanisms as potential new targets for drug development. Such a combination of the experimental assessment of the optokinetic reflex (OKR) or optomotor response (OMR) with other measures of retinal structure and function is especially valuable for research on GON. The chronic progression of the disease is characterized by a gradual decrease in function accompanied by a concomitant increase in structural damage to the retina, therefore the assessment of subtle changes is key to determining the success of novel intervention strategies.
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33
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Induction of autophagy in rats upon overexpression of wild-type and mutant optineurin gene. BMC Cell Biol 2015; 16:14. [PMID: 25943884 PMCID: PMC4429416 DOI: 10.1186/s12860-015-0060-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/22/2015] [Indexed: 12/31/2022] Open
Abstract
Background Optineurin is a gene associated with normal tension glaucoma and amyotrophic lateral sclerosis. It has been reported previously that in cultured RGC5 cells, the turnover of endogenous optineurin involves mainly the ubiquitin-proteasome pathway (UPP). When optineurin is upregulated or mutated, the UPP function is compromised as evidenced by a decreased proteasome β5 subunit (PSMB5) level and autophagy is induced for clearance of the optineurin protein. Results Adeno-associated type 2 viral (AAV2) vectors for green fluorescence protein (GFP) only, GFP-tagged wild-type and Glu50Lys (E50K) mutated optineurin were intravitreally injected into rats for expression in retinal ganglion cells (RGCs). Following intravitreal injections, eyes that received optineurin vectors exhibited retinal thinning, as well as RGC and axonal loss compared to GFP controls. By immunostaining and Western blotting, the level of PSMB5 and autophagic substrate degradation marker p62 was reduced, and the level of autophagic marker microtubule associated protein 1 light chain 3 (LC3) was enhanced. The UPP impairment and autophagy induction evidently occurred in vivo as in vitro. The optineurin level, RGC and axonal counts, and apoptosis in AAV2-E50K-GFP-injected rat eyes were averted to closer to normal limits after treatment with rapamycin, an autophagic enhancer. Conclusions The UPP function was reduced and autophagy was induced when wild-type and E50K optineurin was overexpressed in rat eyes. This study validates the in vitro findings, confirming that UPP impairment and autophagy induction also occur in vivo. In addition, rapamycin is demonstrated to clear the accumulated mutant optineurin. This agent may potentially be useful for rescuing of the adverse optineurin phenotypes in vivo.
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Hauswirth WW. Retinal gene therapy using adeno-associated viral vectors: multiple applications for a small virus. Hum Gene Ther 2015; 25:671-8. [PMID: 25136913 DOI: 10.1089/hum.2014.2530] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- William W Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, FL 32610-0284
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35
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Du W, Tao Y, Deng WT, Zhu P, Li J, Dai X, Zhang Y, Shi W, Liu X, Chiodo VA, Ding XQ, Zhao C, Michalakis S, Biel M, Zhang Z, Qu J, Hauswirth WW, Pang JJ. Vitreal delivery of AAV vectored Cnga3 restores cone function in CNGA3-/-/Nrl-/- mice, an all-cone model of CNGA3 achromatopsia. Hum Mol Genet 2015; 24:3699-707. [PMID: 25855802 DOI: 10.1093/hmg/ddv114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/30/2015] [Indexed: 11/14/2022] Open
Abstract
The CNGA3(-/-)/Nrl(-/-) mouse is a cone-dominant model with Cnga3 channel deficiency, which partially mimics the all cone foveal structure of human achromatopsia 2 with CNGA3 mutations. Although subretinal (SR) AAV vector administration can transfect retinal cells efficiently, the injection-induced retinal detachment can cause retinal damage, particularly when SR vector bleb includes the fovea. We therefore explored whether cone function-structure could be rescued in CNGA3(-/-)/Nrl(-/-) mice by intravitreal (IVit) delivery of tyrosine to phenylalanine (Y-F) capsid mutant AAV8. We find that AAV-mediated CNGA3 expression can restore cone function and rescue structure following IVit delivery of AAV8 (Y447, 733F) vector. Rescue was assessed by restoration of the cone-mediated electroretinogram (ERG), optomotor responses, and cone opsin immunohistochemistry. Demonstration of gene therapy in a cone-dominant mouse model by IVit delivery provides a potential alternative vector delivery mode for safely transducing foveal cones in achromatopsia patients and in other human retinal diseases affecting foveal function.
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Affiliation(s)
- Wei Du
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Ye Tao
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Wen-Tao Deng
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Ping Zhu
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Jie Li
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Xufeng Dai
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA, School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China
| | - Yuxin Zhang
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA, Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Wei Shi
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Xuan Liu
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Vince A Chiodo
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Chen Zhao
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China
| | - Stylianos Michalakis
- Munich Center for Integrated Protein Science and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany and
| | - Martin Biel
- Munich Center for Integrated Protein Science and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany and
| | - Zuoming Zhang
- Department of Clinical Aerospace Medicine, Fourth Military Medical University, Xi'an 710032, China
| | - Jia Qu
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China,
| | - William W Hauswirth
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA,
| | - Ji-Jing Pang
- Deparment of Ophthalmology, University of Florida, Gainesville, FL 32610, USA, School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang 325027, China, Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University and State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China,
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36
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Chacon-Camacho OF, Zenteno JC. Review and update on the molecular basis of Leber congenital amaurosis. World J Clin Cases 2015; 3:112-124. [PMID: 25685757 PMCID: PMC4317604 DOI: 10.12998/wjcc.v3.i2.112] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/03/2014] [Accepted: 11/19/2014] [Indexed: 02/05/2023] Open
Abstract
Inherited retinal diseases are uncommon pathologies and one of the most harmful causes of childhood and adult blindness. Leber congenital amaurosis (LCA) is the most severe kind of these diseases accounting for approximately 5% of the whole retinal dystrophies and 20% of the children that study on blind schools. Clinical ophthalmologic findings including severe vision loss, nystagmus and ERG abnormalities should be suspected through the first year of life in this group of patients. Phenotypic variability is found when LCA patients have a full ophthalmologic examination. However, a correct diagnosis may be carried out; the determination of ophthalmologic clues as light sensibility, night blindness, fundus pigmentation, among other, join with electroretinographics findings, optical coherence tomography, and new technologies as molecular gene testing may help to reach to a precise diagnosis. Several retinal clinical features in LCA may suggest a genetic or gene particular defect; thus genetic-molecular tools could directly corroborate the clinical diagnosis. Currently, approximately 20 genes have been associated to LCA. In this review, historical perspective, clinical ophthalmological findings, new molecular-genetics technologies, possible phenotype-genotypes correlations, and gene therapy for some LCA genes are described.
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O'Reilly M, Federoff HJ, Fong Y, Kohn DB, Patterson AP, Ahmed N, Asokan A, Boye SE, Crystal RG, De Oliveira S, Gargiulo L, Harper SQ, Ikeda Y, Jambou R, Montgomery M, Prograis L, Rosenthal E, Sterman DH, Vandenberghe LH, Zoloth L, Abedi M, Adair J, Adusumilli PS, Goins WF, Gray J, Monahan P, Popplewell L, Sena-Esteves M, Tannous B, Weber T, Wierda W, Gopal-Srivastava R, McDonald CL, Rosenblum D, Corrigan-Curay J. Gene therapy: charting a future course--summary of a National Institutes of Health Workshop, April 12, 2013. Hum Gene Ther 2015; 25:488-97. [PMID: 24773122 DOI: 10.1089/hum.2014.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recently, the gene therapy field has begun to experience clinical successes in a number of different diseases using various approaches and vectors. The workshop Gene Therapy: Charting a Future Course, sponsored by the National Institutes of Health (NIH) Office of Biotechnology Activities, brought together early and mid-career researchers to discuss the key scientific challenges and opportunities, ethical and communication issues, and NIH and foundation resources available to facilitate further clinical advances.
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Affiliation(s)
- Marina O'Reilly
- 1 Office of Science Policy, Office of the Director, National Institutes of Health , Bethesda, MD 20892
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Pierce EA, Bennett J. The Status of RPE65 Gene Therapy Trials: Safety and Efficacy. Cold Spring Harb Perspect Med 2015; 5:a017285. [PMID: 25635059 DOI: 10.1101/cshperspect.a017285] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Several groups have reported the results of clinical trials of gene augmentation therapy for Leber congenital amaurosis (LCA) because of mutations in the RPE65 gene. These studies have used subretinal injection of adeno-associated virus (AAV) vectors to deliver the human RPE65 cDNA to the retinal pigment epithelial (RPE) cells of the treated eyes. In all of the studies reported to date, this approach has been shown to be both safe and effective. The successful clinical trials of gene augmentation therapy for retinal degeneration caused by mutations in the RPE65 gene sets the stage for broad application of gene therapy to treat retinal degenerative disorders.
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Affiliation(s)
- Eric A Pierce
- Department of Ophthalmology, Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts 02114
| | - Jean Bennett
- Department of Ophthalmology, Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
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Trapani I, Puppo A, Auricchio A. Vector platforms for gene therapy of inherited retinopathies. Prog Retin Eye Res 2014; 43:108-28. [PMID: 25124745 PMCID: PMC4241499 DOI: 10.1016/j.preteyeres.2014.08.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/26/2014] [Accepted: 08/02/2014] [Indexed: 12/20/2022]
Abstract
Inherited retinopathies (IR) are common untreatable blinding conditions. Most of them are inherited as monogenic disorders, due to mutations in genes expressed in retinal photoreceptors (PR) and in retinal pigment epithelium (RPE). The retina's compatibility with gene transfer has made transduction of different retinal cell layers in small and large animal models via viral and non-viral vectors possible. The ongoing identification of novel viruses as well as modifications of existing ones based either on rational design or directed evolution have generated vector variants with improved transduction properties. Dozens of promising proofs of concept have been obtained in IR animal models with both viral and non-viral vectors, and some of them have been relayed to clinical trials. To date, recombinant vectors based on the adeno-associated virus (AAV) represent the most promising tool for retinal gene therapy, given their ability to efficiently deliver therapeutic genes to both PR and RPE and their excellent safety and efficacy profiles in humans. However, AAVs' limited cargo capacity has prevented application of the viral vector to treatments requiring transfer of genes with a coding sequence larger than 5 kb. Vectors with larger capacity, i.e. nanoparticles, adenoviral and lentiviral vectors are being exploited for gene transfer to the retina in animal models and, more recently, in humans. This review focuses on the available platforms for retinal gene therapy to fight inherited blindness, highlights their main strengths and examines the efforts to overcome some of their limitations.
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Affiliation(s)
- Ivana Trapani
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Agostina Puppo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy.
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Abstract
Leber congenital amaurosis (LCA) is a clinically and genetically heterogeneous group of diseases that account for the most severe form of early-onset retinal dystrophy. Mutations in retinal guanylate cyclase-1 (GUCY2D) are associated with LCA1, a prevalent form. GUCY2D encodes guanylate cyclase-1 (GC1), a protein expressed in rod and cone photoreceptors that regulates cGMP and Ca(2+) levels within these cells. LCA1 patients present with severely impaired vision, reduced, or ablated electroretinogram and nystagmus. Despite a high degree of visual disturbance, LCA1 patients retain normal photoreceptor laminar architecture, except for foveal cone outer segment abnormalities and, in some patients, foveal cone loss. This article will summarize clinical characterization of patients and proof of concept gene replacement studies in several animal models of GC1 deficiency, both of which have laid the groundwork for clinical application of a gene therapy for treatment of LCA1.
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Tran NM, Chen S. Mechanisms of blindness: animal models provide insight into distinct CRX-associated retinopathies. Dev Dyn 2014; 243:1153-66. [PMID: 24888636 DOI: 10.1002/dvdy.24151] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/24/2014] [Accepted: 05/10/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The homeodomain transcription factor CRX is a crucial regulator of mammalian photoreceptor gene expression. Mutations in the human CRX gene are associated with dominant inherited retinopathies Retinitis Pigmentosa (RP), Cone-Rod Dystrophy (CoRD), and Leber Congenital Amaurosis (LCA), of varying severity. In vitro and in vivo assessment of mutant CRX proteins have revealed pathogenic mechanisms for several mutations, but no comprehensive mutation-disease correlation has yet been reported. RESULTS Here we describe four different classes of disease-causing CRX mutations, characterized by mutation type, pathogenetic mechanism, and the molecular activity of the mutant protein: (1) hypomorphic missense mutations with reduced DNA binding, (2) antimorphic missense mutations with variable DNA binding, (3) antimorphic frameshift/nonsense mutations with intact DNA binding, and (4) antimorphic frameshift mutations with reduced DNA binding. Mammalian models representing three of these classes have been characterized. CONCLUSIONS Models carrying Class I mutations display a mild dominant retinal phenotype and recessive LCA, while models carrying Class III and IV mutations display characteristically distinct dominant LCA phenotypes. These animal models also reveal unexpected pathogenic mechanisms underlying CRX-associated retinopathies. The complexity of genotype-phenotype correlation for CRX-associated diseases highlights the value of developing comprehensive "true-to-disease" animal models for understanding pathologic mechanisms and testing novel therapeutic approaches.
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Affiliation(s)
- Nicholas M Tran
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri
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Abstract
Significant advances have been made over the last decade or two in the elucidation of the molecular pathogenesis of inherited ocular disorders. In particular, remarkable successes have been achieved in exploration of gene-based medicines for these conditions, both in preclinical and in clinical studies. Progress in the development of gene therapies targeted toward correcting the primary genetic defect or focused on modulating secondary effects associated with retinal pathologies are discussed in the review. Likewise, the recent utilization of genes encoding light-sensing molecules to provide new functions to residual retinal cells in the degenerating retina is discussed. While a great deal has been learned over the last two decades, the next decade should result in an increasing number of preclinical studies progressing to human clinical trial, an exciting prospect for patients, those active in research and development and bystanders alike.
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Boye SE. Insights gained from gene therapy in animal models of retGC1 deficiency. Front Mol Neurosci 2014; 7:43. [PMID: 24860425 PMCID: PMC4030156 DOI: 10.3389/fnmol.2014.00043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/26/2014] [Indexed: 12/29/2022] Open
Abstract
Vertebrate species possess two retinal guanylate cyclases (retGC1 and retGC2) and at least two guanylate cyclase activating proteins (GCAPs), GCAP1 and GCAP2. GCAPs function as Ca2+ sensors that regulate the activity of guanylate cyclases. Together, these proteins regulate cGMP and Ca2+ levels within the outer segments of rod and cone photoreceptors. Mutations in GUCY2D, the gene that encodes retGC1, are a leading cause of the most severe form of early onset retinal dystrophy, Leber congenital amaurosis (LCA1). These mutations, which reduce or abolish the ability of retGC1 to replenish cGMP in photoreceptors, are thought to lead to the biochemical equivalent of chronic light exposure in these cells. In spite of this, the majority of LCA1 patients retain normal photoreceptor laminar architecture aside from foveal cone outer segment abnormalities, suggesting they may be good candidates for gene replacement therapy. Work began in the 1980s to characterize multiple animal models of retGC1 deficiency. 34 years later, all models have been used in proof of concept gene replacement studies toward the goal of developing a therapy to treat GUCY2D-LCA1. Here we use the results of these studies as well as those of recent clinical studies to address specific questions relating to clinical application of a gene therapy for treatment of LCA1.
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Affiliation(s)
- Shannon E Boye
- Department of Ophthalmology, University of Florida Gainesville, FL, USA
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A detailed phenotypic description of autosomal dominant cone dystrophy due to a de novo mutation in the GUCY2D gene. Eye (Lond) 2014; 28:481-7. [PMID: 24480840 DOI: 10.1038/eye.2014.7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 12/10/2013] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The purpose of this study is to describe the phenotype of a family with de novo mutation in the GUCY2D. MATERIALS AND METHODS Five subjects, including two monozygotic twins, underwent ophthalmic clinical examination while some had autofluorescence imaging (AF) and optical coherence tomography (OCT). Symptomatic individuals underwent electrophysiological testing. The youngest subject (21 years) was also evaluated psychophysically. DNA obtained from the individuals was screened for mutations in GUCY2D. Microsatellite markers were used to determine the haplotype of 17p surrounding the GUCY2D gene. RESULTS The youngest subject had 6/18 visual acuity, an annulus of hyper-autofluorescence in the perifoveal region, and a subfoveal absence of outer segments on OCT. In the older individuals, severe thinning of inner retina and a patchy loss of photoreceptors and retinal pigment epithelium were observed in the perifoveal region. All three showed generalised cone system dysfunction with preserved rod function on electrophysiology. Psychophysical evaluation was consistent with poor cone function. Screening of the GUCY2D gene revealed the mutation p.R838H in all the affected individuals and was absent in the asymptomatic patients. Haplotyping showed that the mutation originated from the unaffected mother. CONCLUSIONS Autosomal dominant cone dystrophy due to GUCY2D can occur without a history in the antecedents due to a de novo mutation. This is important to consider in any simplex case with a similar phenotype. The phenotype description of this disorder is expanded with detailed description of the OCT findings. This paper describes the concordance of the phenotypic findings in the monozygotic twins.
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Shukla R, Kannabiran C, Jalali S. Genetics of Leber congenital amaurosis: an update. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Manfredi A, Marrocco E, Puppo A, Cesi G, Sommella A, Della Corte M, Rossi S, Giunti M, Craft CM, Bacci ML, Simonelli F, Surace EM, Auricchio A. Combined rod and cone transduction by adeno-associated virus 2/8. Hum Gene Ther 2013; 24:982-92. [PMID: 24067103 DOI: 10.1089/hum.2013.154] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Gene transfer to both cone and rod photoreceptors (PRs) is essential for gene therapy of inherited retinal degenerations that are caused by mutations in genes expressed in both PR types. Vectors based on the adeno-associated virus (AAV) efficiently transduce PRs of different species. However, these are predominantly rods and little is known about the ability of the AAV to transduce cones in combination with rods. Here we show that AAV2/8 transduces pig cones to levels that are similar to AAV2/9, and the outer nuclear layer (mainly rods) to levels that are on average higher, although not statistically significant, than both AAV2/5 and AAV2/9. We additionally found that the ubiquitous cytomegalovirus (CMV), but not the PR-specific GRK1 promoter, transduced pig cones efficiently, presumably because GRK1 is not expressed in pig cones as observed in mice and humans. Indeed, the GRK1 and CMV promoters transduce a similar percentage of murine cones with the CMV reaching the highest expression levels. Consistent with this, the AAV2/8 vectors with either the CMV or the GRK1 promoter restore cone function in a mouse model of Leber congenital amaurosis type 1 (LCA1), supporting the use of AAV2/8 for gene therapy of LCA1 as well as of other retinal diseases requiring gene transfer to both PR types.
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Affiliation(s)
- Anna Manfredi
- 1 Telethon Institute of Genetics and Medicine , Naples 80131, Italy
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Successful gene therapy in the RPGRIP1-deficient dog: a large model of cone-rod dystrophy. Mol Ther 2013; 22:265-277. [PMID: 24091916 DOI: 10.1038/mt.2013.232] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 09/22/2013] [Indexed: 12/31/2022] Open
Abstract
For the development of new therapies, proof-of-concept studies in large animal models that share clinical features with their human counterparts represent a pivotal step. For inherited retinal dystrophies primarily involving photoreceptor cells, the efficacy of gene therapy has been demonstrated in canine models of stationary cone dystrophies and progressive rod-cone dystrophies but not in large models of progressive cone-rod dystrophies, another important cause of blindness. To address the last issue, we evaluated gene therapy in the retinitis pigmentosa GTPase regulator interacting protein 1 (RPGRIP1)-deficient dog, a model exhibiting a severe cone-rod dystrophy similar to that seen in humans. Subretinal injection of AAV5 (n = 5) or AAV8 (n = 2) encoding the canine Rpgrip1 improved photoreceptor survival in transduced areas of treated retinas. Cone function was significantly and stably rescued in all treated eyes (18-72% of those recorded in normal eyes) up to 24 months postinjection. Rod function was also preserved (22-29% of baseline function) in four of the five treated dogs up to 24 months postinjection. No detectable rod function remained in untreated contralateral eyes. More importantly, treatment preserved bright- and dim-light vision. Efficacy of gene therapy in this large animal model of cone-rod dystrophy provides great promise for human treatment.
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Boye SL, Peshenko IV, Huang WC, Min SH, McDoom I, Kay CN, Liu X, Dyka FM, Foster TC, Umino Y, Karan S, Jacobson SG, Baehr W, Dizhoor A, Hauswirth WW, Boye SE. AAV-mediated gene therapy in the guanylate cyclase (RetGC1/RetGC2) double knockout mouse model of Leber congenital amaurosis. Hum Gene Ther 2013; 24:189-202. [PMID: 23210611 DOI: 10.1089/hum.2012.193] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mutations in GUCY2D are associated with recessive Leber congenital amaurosis-1 (LCA1). GUCY2D encodes photoreceptor-specific, retinal guanylate cyclase-1 (RetGC1). Reports of retinal degeneration in LCA1 are conflicting; some describe no obvious degeneration and others report loss of both rods and cones. Proof of concept studies in models representing the spectrum of phenotypes is warranted. We have previously demonstrated adeno-associated virus (AAV)-mediated RetGC1 is therapeutic in GC1ko mice, a model exhibiting loss of cones only. The purpose of this study was to characterize AAV-mediated gene therapy in the RetGC1/RetGC2 double knockout (GCdko) mouse, a model lacking rod and cone function and exhibiting progressive loss of both photoreceptor subclasses. Use of this model also allowed for the evaluation of the functional efficiency of transgenic RetGC1 isozyme. Subretinal delivery of AAV8(Y733F) vector containing the human rhodopsin kinase (hGRK1) promoter driving murine Gucy2e was performed in GCdko mice at various postnatal time points. Treatment resulted in restoration of rod and cone function at all treatment ages and preservation of retinal structure in GCdko mice treated as late as 7 weeks of age. Functional gains and structural preservation were stable for at least 1 year. Treatment also conferred cortical- and subcortical-based visually-guided behavior. Functional efficiency of transgenic RetGC1 was indistinguishable from that of endogenous isozyme in congenic wild-type (WT) mice. This study clearly demonstrates AAV-mediated RetGC1 expression restores function to and preserves structure of rod and cone photoreceptors in a degenerative model of retinal guanylate cyclase deficiency, further supporting development of an AAV-based vector for treatment of LCA1.
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Affiliation(s)
- Sanford L Boye
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
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Willett K, Bennett J. Immunology of AAV-Mediated Gene Transfer in the Eye. Front Immunol 2013; 4:261. [PMID: 24009613 PMCID: PMC3757345 DOI: 10.3389/fimmu.2013.00261] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 08/16/2013] [Indexed: 12/20/2022] Open
Abstract
The eye has been at the forefront of translational gene therapy largely owing to suitable disease targets, anatomic accessibility, and well-studied immunologic privilege. These advantages have fostered research culminating in several clinical trials and adeno-associated virus (AAV) has emerged as the vector of choice for many ocular therapies. Pre-clinical and clinical investigations have assessed the humoral and cellular immune responses to a variety of naturally occurring and engineered AAV serotypes as well as their delivered transgenes and these data have been correlated to potential clinical sequelae. Encouragingly, AAV appears safe and effective with clinical follow-up surpassing 5 years in some studies. As disease targets continue to expand for AAV in the eye, thorough and deliberate assessment of immunologic safety is critical. With careful study, the development of these technologies should concurrently inform the biology of the ocular immune response.
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Affiliation(s)
- Keirnan Willett
- Department of Ophthalmology, Scheie Eye Institute, F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania , Philadelphia, PA , USA
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