1
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Sarkar A, Junnuthula V, Dyawanapelly S. Ocular Therapeutics and Molecular Delivery Strategies for Neovascular Age-Related Macular Degeneration (nAMD). Int J Mol Sci 2021; 22:10594. [PMID: 34638935 PMCID: PMC8508687 DOI: 10.3390/ijms221910594] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of vision loss in geriatric population. Intravitreal (IVT) injections are popular clinical option. Biologics and small molecules offer efficacy but relatively shorter half-life after intravitreal injections. To address these challenges, numerous technologies and therapies are under development. Most of these strategies aim to reduce the frequency of injections, thereby increasing patient compliance and reducing patient-associated burden. Unlike IVT frequent injections, molecular therapies such as cell therapy and gene therapy offer restoration ability hence gained a lot of traction. The recent approval of ocular gene therapy for inherited disease offers new hope in this direction. However, until such breakthrough therapies are available to the majority of patients, antibody therapeutics will be on the shelf, continuing to provide therapeutic benefits. The present review aims to highlight the status of pre-clinical and clinical studies of neovascular AMD treatment modalities including Anti-VEGF therapy, upcoming bispecific antibodies, small molecules, port delivery systems, photodynamic therapy, radiation therapy, gene therapy, cell therapy, and combination therapies.
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Affiliation(s)
- Aira Sarkar
- Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA;
| | | | - Sathish Dyawanapelly
- Department of Pharmaceutical Sciences & Technology, Institute of Chemical Technology, Nathalal Parekh Marg, Mumbai 400019, India
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2
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Sinenko SA, Ponomartsev SV, Tomilin AN. Pluripotent stem cell-based gene therapy approach: human de novo synthesized chromosomes. Cell Mol Life Sci 2021; 78:1207-1220. [PMID: 33011821 PMCID: PMC11072874 DOI: 10.1007/s00018-020-03653-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/14/2020] [Accepted: 09/22/2020] [Indexed: 02/06/2023]
Abstract
A novel approach in gene therapy was introduced 20 years ago since artificial non-integrative chromosome-based vectors containing gene loci size inserts were engineered. To date, different human artificial chromosomes (HAC) were generated with the use of de novo construction or "top-down" engineering approaches. The HAC-based therapeutic approach includes ex vivo gene transferring and correction of pluripotent stem cells (PSCs) or highly proliferative modified stem cells. The current progress in the technology of induced PSCs, integrating with the HAC technology, resulted in a novel platform of stem cell-based tissue replacement therapy for the treatment of genetic disease. Nowadays, the sophisticated and laborious HAC technology has significantly improved and is now closer to clinical studies. In here, we reviewed the achievements in the technology of de novo synthesized HACs for a chromosome transfer for developing gene therapy tissue replacement models of monogenic human diseases.
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Affiliation(s)
- Sergey A Sinenko
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave, St-Petersburg, 194064, Russia.
| | - Sergey V Ponomartsev
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave, St-Petersburg, 194064, Russia
| | - Alexey N Tomilin
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Ave, St-Petersburg, 194064, Russia.
- Institute of Translational Biomedicine, St-Petersburg State University, 7-9, Universitetskaya Emb, St-Petersburg, 199034, Russia.
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3
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Ruan Y, Jiang S, Gericke A. Age-Related Macular Degeneration: Role of Oxidative Stress and Blood Vessels. Int J Mol Sci 2021; 22:ijms22031296. [PMID: 33525498 PMCID: PMC7866075 DOI: 10.3390/ijms22031296] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/25/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is a common irreversible ocular disease characterized by vision impairment among older people. Many risk factors are related to AMD and interact with each other in its pathogenesis. Notably, oxidative stress and choroidal vascular dysfunction were suggested to be critically involved in AMD pathogenesis. In this review, we give an overview on the factors contributing to the pathophysiology of this multifactorial disease and discuss the role of reactive oxygen species and vascular function in more detail. Moreover, we give an overview on therapeutic strategies for patients suffering from AMD.
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Affiliation(s)
- Yue Ruan
- Correspondence: (Y.R.); (A.G.); Tel.: +49-6131-178-276 (Y.R. & A.G.)
| | | | - Adrian Gericke
- Correspondence: (Y.R.); (A.G.); Tel.: +49-6131-178-276 (Y.R. & A.G.)
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4
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Sinenko SA, Ponomartsev SV, Tomilin AN. Human artificial chromosomes for pluripotent stem cell-based tissue replacement therapy. Exp Cell Res 2020; 389:111882. [DOI: 10.1016/j.yexcr.2020.111882] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/23/2020] [Accepted: 01/29/2020] [Indexed: 02/08/2023]
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5
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Moore NA, Bracha P, Hussain RM, Morral N, Ciulla TA. Gene therapy for age-related macular degeneration. Expert Opin Biol Ther 2017; 17:1235-1244. [PMID: 28726562 DOI: 10.1080/14712598.2017.1356817] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
INTRODUCTION In neovascular age related macular degeneration (nAMD), gene therapy to chronically express anti-vascular endothelial growth factor (VEGF) proteins could ameliorate the treatment burden of chronic intravitreal therapy and improve limited visual outcomes associated with 'real world' undertreatment. Areas covered: In this review, the authors assess the evolution of gene therapy for AMD. Adeno-associated virus (AAV) vectors can transduce retinal pigment epithelium; one such early application was a phase I trial of AAV2-delivered pigment epithelium derived factor gene in advanced nAMD. Subsequently, gene therapy for AMD shifted to the investigation of soluble fms-like tyrosine kinase-1 (sFLT-1), an endogenously expressed VEGF inhibitor, binding and neutralizing VEGF-A. After some disappointing results, research has centered on novel vectors, including optimized AAV2, AAV8 and lentivirus, as well as genes encoding other anti-angiogenic proteins, including ranibizumab, aflibercept, angiostatin and endostatin. Also, gene therapy targeting the complement system is being investigated for geographic atrophy due to non-neovascular AMD. Expert opinion: The success of gene therapy for AMD will depend on the selection of the most appropriate therapeutic protein and its level of chronic expression. Future investigations will center on optimizing vector, promoter and delivery methods, and evaluating the risks of the chronic expression of anti-angiogenic or anti-complement proteins.
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Affiliation(s)
- Nicholas A Moore
- a Department of Ophthalmology , Indiana University School of Medicine , Indianapolis , IN , USA
| | - Peter Bracha
- a Department of Ophthalmology , Indiana University School of Medicine , Indianapolis , IN , USA
| | - Rehan M Hussain
- a Department of Ophthalmology , Indiana University School of Medicine , Indianapolis , IN , USA
| | - Nuria Morral
- c Department of Medical and Molecular Genetics , Indiana University School of Medicine , Indianapolis , IN , USA
| | - Thomas A Ciulla
- a Department of Ophthalmology , Indiana University School of Medicine , Indianapolis , IN , USA.,b Retina Service , Midwest Eye Institute , Indianapolis , IN , USA
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6
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Trapani I, Banfi S, Simonelli F, Surace EM, Auricchio A. Gene therapy of inherited retinal degenerations: prospects and challenges. Hum Gene Ther 2016; 26:193-200. [PMID: 25762209 DOI: 10.1089/hum.2015.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Because of its favorable anatomical and immunological characteristics, the eye has been at the forefront of translational gene therapy. Dozens of promising proofs of concept have been obtained in animal models of inherited retinal degenerations (IRDs), and some of them have been relayed to the clinic. The results from the first clinical trials for a congenital form of blindness have generated great interest and have demonstrated the safety and efficacy of intraocular administrations of viral vectors in humans. However, this progress has also generated new questions and posed challenges that need to be addressed to further expand the applicability of gene therapy in the eye, including safe delivery of viral vectors to the outer retina, treatment of dominant IRDs as well as of IRDs caused by mutations in large genes, and, finally, selection of the appropriate IRDs and patients to maximize the efficacy of gene transfer. This review summarizes the strategies that are currently being exploited to overcome these challenges and drive the clinical development of retinal gene therapy.
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Affiliation(s)
- Ivana Trapani
- 1 Telethon Institute of Genetics and Medicine (TIGEM) , Pozzuoli, Naples 80078, Italy
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7
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Halder S, Van Vliet K, Smith JK, Duong TTP, McKenna R, Wilson JM, Agbandje-McKenna M. Structure of neurotropic adeno-associated virus AAVrh.8. J Struct Biol 2015; 192:21-36. [PMID: 26334681 PMCID: PMC4617535 DOI: 10.1016/j.jsb.2015.08.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 08/22/2015] [Accepted: 08/30/2015] [Indexed: 12/19/2022]
Abstract
Adeno-associated virus rhesus isolate 8 (AAVrh.8) is a leading vector for the treatment of neurological diseases due to its efficient transduction of neuronal cells and reduced peripheral tissue tropism. Toward identification of the capsid determinants for these properties, the structure of AAVrh.8 was determined by X-ray crystallography to 3.5 Å resolution and compared to those of other AAV isolates. The capsid viral protein (VP) structure consists of an αA helix and an eight-stranded anti-parallel β-barrel core conserved in parvoviruses, and large insertion loop regions between the β-strands form the capsid surface topology. The AAVrh.8 capsid exhibits the surface topology conserved in all AAVs: depressions at the icosahedral twofold axis and surrounding the cylindrical channel at the fivefold axis, and three protrusions around the threefold axis. A structural comparison to serotypes AAV2, AAV8, and AAV9, to which AAVrh.8 shares ∼ 84%, ∼ 91%, and ∼ 87% VP sequence identity, respectively, revealed differences in the surface loops known to affect receptor binding, transduction efficiency, and antigenicity. Consistent with this observation, biochemical assays showed that AAVrh.8 is unable to bind heparin and does not cross-react with conformational monoclonal antibodies and human donor serum directed against the other AAVs compared. This structure of AAVrh.8 thus identified capsid surface differences which can serve as template regions for rational design of vectors with enhanced transduction for specific tissues and escape pre-existing antibody recognition. These features are essential for the creation of an AAV vector toolkit that is amenable to personalized disease treatment.
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Affiliation(s)
- Sujata Halder
- University of Florida, Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, Gainesville, FL 32610, USA
| | - Kim Van Vliet
- University of Florida, Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, Gainesville, FL 32610, USA
| | - J Kennon Smith
- University of Florida, Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, Gainesville, FL 32610, USA
| | - Thao Thi Phuong Duong
- University of Florida, Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, Gainesville, FL 32610, USA
| | - Robert McKenna
- University of Florida, Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, Gainesville, FL 32610, USA
| | - James M Wilson
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mavis Agbandje-McKenna
- University of Florida, Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, Gainesville, FL 32610, USA.
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8
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Cronin T, Vandenberghe LH, Hantz P, Juttner J, Reimann A, Kacsó AE, Huckfeldt RM, Busskamp V, Kohler H, Lagali PS, Roska B, Bennett J. Efficient transduction and optogenetic stimulation of retinal bipolar cells by a synthetic adeno-associated virus capsid and promoter. EMBO Mol Med 2015; 6:1175-90. [PMID: 25092770 PMCID: PMC4197864 DOI: 10.15252/emmm.201404077] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this report, we describe the development of a modified adeno-associated virus (AAV) capsid and promoter for transduction of retinal ON-bipolar cells. The bipolar cells, which are post-synaptic to the photoreceptors, are important retinal targets for both basic and preclinical research. In particular, a therapeutic strategy under investigation for advanced forms of blindness involves using optogenetic molecules to render ON-bipolar cells light-sensitive. Currently, delivery of adequate levels of gene expression is a limiting step for this approach. The synthetic AAV capsid and promoter described here achieves high level of optogenetic transgene expression in ON-bipolar cells. This evokes high-frequency (∼100 Hz) spiking responses in ganglion cells of previously blind, rd1, mice. Our vector is a promising vehicle for further development toward potential clinical use.
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Affiliation(s)
- Therese Cronin
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Luk H Vandenberghe
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Péter Hantz
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Josephine Juttner
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Andreas Reimann
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | | | - Rachel M Huckfeldt
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Volker Busskamp
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland Genetics Department, Harvard Medical School, Boston, MA, USA
| | - Hubertus Kohler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Pamela S Lagali
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Botond Roska
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Jean Bennett
- Center for Advanced Retinal and Ophthalmic Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
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9
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Vandecasteele M, Senova YS, Palfi S, Dugué GP. Potentiel thérapeutique de la neuromodulation optogénétique. Med Sci (Paris) 2015; 31:404-16. [DOI: 10.1051/medsci/20153104015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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10
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Yvon C, Ramsden CM, Lane A, Powner MB, da Cruz L, Coffey PJ, Carr AJF. Using Stem Cells to Model Diseases of the Outer Retina. Comput Struct Biotechnol J 2015; 13:382-9. [PMID: 26106463 PMCID: PMC4477013 DOI: 10.1016/j.csbj.2015.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/30/2015] [Accepted: 05/01/2015] [Indexed: 12/13/2022] Open
Abstract
Retinal degeneration arises from the loss of photoreceptors or retinal pigment epithelium (RPE). It is one of the leading causes of irreversible blindness worldwide with limited effective treatment options. Generation of induced pluripotent stem cell (IPSC)-derived retinal cells and tissues from individuals with retinal degeneration is a rapidly evolving technology that holds a great potential for its use in disease modelling. IPSCs provide an ideal platform to investigate normal and pathological retinogenesis, but also deliver a valuable source of retinal cell types for drug screening and cell therapy. In this review, we will provide some examples of the ways in which IPSCs have been used to model diseases of the outer retina including retinitis pigmentosa (RP), Usher syndrome (USH), Leber congenital amaurosis (LCA), gyrate atrophy (GA), juvenile neuronal ceroid lipofuscinosis (NCL), Best vitelliform macular dystrophy (BVMD) and age related macular degeneration (AMD).
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Affiliation(s)
- Camille Yvon
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Conor M. Ramsden
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust, UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - Amelia Lane
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Michael B. Powner
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Lyndon da Cruz
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust, UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - Peter J. Coffey
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- Center for Stem Cell Biology and Engineering, NRI, UC, Santa Barbara, USA
| | - Amanda-Jayne F. Carr
- The London Project to Cure Blindness, Division of ORBIT, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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11
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Gene Therapy with Endogenous Inhibitors of Angiogenesis for Neovascular Age-Related Macular Degeneration: Beyond Anti-VEGF Therapy. J Ophthalmol 2015; 2015:201726. [PMID: 25821585 PMCID: PMC4363820 DOI: 10.1155/2015/201726] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/08/2014] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of substantial and irreversible vision loss amongst elderly populations in industrialized countries. The advanced neovascular (or “wet”) form of the disease is responsible for severe and aggressive loss of central vision. Current treatments aim to seal off leaky blood vessels via laser therapy or to suppress vessel leakage and neovascular growth through intraocular injections of antibodies that target vascular endothelial growth factor (VEGF). However, the long-term success of anti-VEGF therapy can be hampered by limitations such as low or variable efficacy, high frequency of administration (usually monthly), potentially serious side effects, and, most importantly, loss of efficacy with prolonged treatment. Gene transfer of endogenous antiangiogenic proteins is an alternative approach that has the potential to provide long-term suppression of neovascularization and/or excessive vascular leakage in the eye. Preclinical studies of gene transfer in a large animal model have provided impressive preliminary results with a number of transgenes. In addition, a clinical trial in patients suffering from advanced neovascular AMD has provided proof-of-concept for successful gene transfer. In this mini review, we summarize current theories pertaining to the application of gene therapy for neovascular AMD and the potential benefits when used in conjunction with endogenous antiangiogenic proteins.
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12
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Nanoparticle-based technologies for retinal gene therapy. Eur J Pharm Biopharm 2015; 95:353-67. [PMID: 25592325 DOI: 10.1016/j.ejpb.2014.12.028] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/15/2014] [Accepted: 12/22/2014] [Indexed: 01/17/2023]
Abstract
For patients with hereditary retinal diseases, retinal gene therapy offers significant promise for the prevention of retinal degeneration. While adeno-associated virus (AAV)-based systems remain the most popular gene delivery method due to their high efficiency and successful clinical results, other delivery systems, such as non-viral nanoparticles (NPs) are being developed as additional therapeutic options. NP technologies come in several categories (e.g., polymer, liposomes, peptide compacted DNA), several of which have been tested in mouse models of retinal disease. Here, we discuss the key biochemical features of the different NPs that influence how they are internalized into cells, escape from endosomes, and are delivered into the nucleus. We review the primary mechanism of NP uptake by retinal cells and highlight various NPs that have been successfully used for in vivo gene delivery to the retina and RPE. Finally, we consider the various strategies that can be implemented in the plasmid DNA to generate persistent, high levels of gene expression.
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13
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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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14
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Marc R, Pfeiffer R, Jones B. Retinal prosthetics, optogenetics, and chemical photoswitches. ACS Chem Neurosci 2014; 5:895-901. [PMID: 25089879 PMCID: PMC4210130 DOI: 10.1021/cn5001233] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
![]()
Three
technologies have emerged as therapies to restore light sensing to
profoundly blind patients suffering from late-stage retinal degenerations:
(1) retinal prosthetics, (2) optogenetics, and (3) chemical photoswitches.
Prosthetics are the most mature and the only approach in clinical
practice. Prosthetic implants require complex surgical intervention
and provide only limited visual resolution but can potentially restore
navigational ability to many blind patients. Optogenetics uses viral
delivery of type 1 opsin genes from prokaryotes or eukaryote algae
to restore light responses in survivor neurons. Targeting and expression
remain major problems, but are potentially soluble. Importantly, optogenetics
could provide the ultimate in high-resolution vision due to the long
persistence of gene expression achieved in animal models. Nevertheless,
optogenetics remains challenging to implement in human eyes with large
volumes, complex disease progression, and physical barriers to viral
penetration. Now, a new generation of photochromic ligands or chemical
photoswitches (azobenzene-quaternary ammonium derivatives) can be
injected into a degenerated mouse eye and, in minutes to hours, activate
light responses in neurons. These photoswitches offer the potential
for rapidly and reversibly screening the vision restoration expected
in an individual patient. Chemical photoswitch variants that persist
in the cell membrane could make them a simple therapy of choice, with
resolution and sensitivity equivalent to optogenetics approaches.
A major complexity in treating retinal degenerations is retinal remodeling:
pathologic network rewiring, molecular reprogramming, and cell death
that compromise signaling in the surviving retina. Remodeling forces
a choice between upstream and downstream targeting, each engaging
different benefits and defects. Prosthetics and optogenetics can be
implemented in either mode, but the use of chemical photoswitches
is currently limited to downstream implementations. Even so, given
the high density of human foveal ganglion cells, the ultimate chemical
photoswitch treatment could deliver cost-effective, high-resolution
vision for the blind.
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Affiliation(s)
- Robert Marc
- Department of Ophthalmology, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
| | - Rebecca Pfeiffer
- Department of Ophthalmology, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
| | - Bryan Jones
- Department of Ophthalmology, University of Utah School of Medicine, Salt Lake City, Utah 84132, United States
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15
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D'Amico JM, Condliffe EG, Martins KJB, Bennett DJ, Gorassini MA. Recovery of neuronal and network excitability after spinal cord injury and implications for spasticity. Front Integr Neurosci 2014; 8:36. [PMID: 24860447 PMCID: PMC4026713 DOI: 10.3389/fnint.2014.00036] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/17/2014] [Indexed: 01/08/2023] Open
Abstract
The state of areflexia and muscle weakness that immediately follows a spinal cord injury (SCI) is gradually replaced by the recovery of neuronal and network excitability, leading to both improvements in residual motor function and the development of spasticity. In this review we summarize recent animal and human studies that describe how motoneurons and their activation by sensory pathways become hyperexcitable to compensate for the reduction of functional activation of the spinal cord and the eventual impact on the muscle. Specifically, decreases in the inhibitory control of sensory transmission and increases in intrinsic motoneuron excitability are described. We present the idea that replacing lost patterned activation of the spinal cord by activating synaptic inputs via assisted movements, pharmacology or electrical stimulation may help to recover lost spinal inhibition. This may lead to a reduction of uncontrolled activation of the spinal cord and thus, improve its controlled activation by synaptic inputs to ultimately normalize circuit function. Increasing the excitation of the spinal cord with spared descending and/or peripheral inputs by facilitating movement, instead of suppressing it pharmacologically, may provide the best avenue to improve residual motor function and manage spasticity after SCI.
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Affiliation(s)
- Jessica M D'Amico
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada
| | - Elizabeth G Condliffe
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada ; Department of Biomedical Engineering, University of Alberta Edmonton, AB, Canada ; Division of Physical Medicine and Rehabilitation, University of Alberta Edmonton, AB, Canada
| | - Karen J B Martins
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Physical Education and Recreation, University of Alberta Edmonton, AB, Canada
| | - David J Bennett
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Rehabilitation Medicine, University of Alberta Edmonton, AB, Canada
| | - Monica A Gorassini
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada ; Department of Biomedical Engineering, University of Alberta Edmonton, AB, Canada
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16
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Cell therapy using retinal progenitor cells shows therapeutic effect in a chemically-induced rotenone mouse model of Leber hereditary optic neuropathy. Eur J Hum Genet 2014; 22:1314-20. [PMID: 24569607 DOI: 10.1038/ejhg.2014.26] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/19/2013] [Accepted: 12/26/2013] [Indexed: 01/08/2023] Open
Abstract
Primary mitochondrial disorders occur at a prevalence of one in 10 000; ∼50% of these demonstrate ocular pathology. Leber hereditary optic neuropathy (LHON) is the most common primary mitochondrial disorder. LHON results from retinal ganglion cell pathology, which leads to optic nerve degeneration and blindness. Over 95% of cases result from one of the three common mutations in mitochondrial genes MTND1, MTND4 and MTND6, which encode elements of the complex I respiratory chain. Various therapies for LHON are in development, for example, intravitreal injection of adeno-associated virus carrying either the yeast NDI1 gene or a specific subunit of mammalian Complex I have shown visual improvement in animal models. Given the course of LHON, it is likely that in many cases prompt administration may be necessary before widespread cell death. An alternative approach for therapy may be the use of stem cells to protect visual function; this has been evaluated by us in a rotenone-induced model of LHON. Freshly dissected embryonic retinal cells do not integrate into the ganglion cell layer (GCL), unlike similarly obtained photoreceptor precursors. However, cultured retinal progenitor cells can integrate in close proximity to the GCL, and act to preserve retinal function as assessed by manganese-enhanced magnetic resonance imaging, optokinetic responses and ganglion cell counts. Cell therapies for LHON therefore represent a promising therapeutic approach, and may be of particular utility in treating more advanced disease.
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17
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Kouprina N, Tomilin AN, Masumoto H, Earnshaw WC, Larionov V. Human artificial chromosome-based gene delivery vectors for biomedicine and biotechnology. Expert Opin Drug Deliv 2014; 11:517-35. [DOI: 10.1517/17425247.2014.882314] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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18
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Shastry BS. Genetics of familial exudative vitreoretinopathy and its implications for management. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.40] [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: 01/18/2023]
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19
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Venkatesh A, Ma S, Langellotto F, Gao G, Punzo C. Retinal gene delivery by rAAV and DNA electroporation. ACTA ACUST UNITED AC 2013; Chapter 14:Unit 14D.4. [PMID: 23408132 DOI: 10.1002/9780471729259.mc14d04s28] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ocular gene therapy is a fast-growing area of research. The eye is an ideal organ for gene therapy since it is immune privileged and easily accessible, and direct viral delivery results primarily in local infection. Because the eye is not a vital organ, mutations in eye-specific genes tend to be more common. To date, over 40 eye-specific genes have been identified harboring mutations that lead to blindness. Gene therapy with recombinant adeno-associated virus (rAAV) holds the promise to treat patients with such mutations. However, proof-of-concept and safety evaluation for gene therapy remains to be established for most of these diseases. This unit describes the in vivo delivery of genes to the mouse eye by rAAV-mediated gene transfer and plasmid DNA electroporation. Advantages and limitations of these methods are discussed, and detailed protocols for gene delivery, required materials, and subsequent tissue processing methods are described.
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Affiliation(s)
- Aditya Venkatesh
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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20
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Lustremant C, Habeler W, Plancheron A, Goureau O, Grenot L, de la Grange P, Audo I, Nandrot EF, Monville C. Human induced pluripotent stem cells as a tool to model a form of Leber congenital amaurosis. Cell Reprogram 2013; 15:233-46. [PMID: 23663011 DOI: 10.1089/cell.2012.0076] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Our purpose was to investigate genes and molecular mechanisms involved in patients with Leber congenital amaurosis (LCA) and to model this type of LCA for drug screening. Fibroblasts from two unrelated clinically identified patients with a yet undetermined gene mutation were reprogrammed to pluripotency by retroviral transduction. These human induced pluripotent stem cells (hiPSCs) were differentiated into neural stem cells (NSCs) that mimicked the neural tube stage and retinal pigmented epithelial (RPE) cells that could be targeted by the disease. A genome-wide transcriptome analysis was performed with Affymetrix Exon Array GeneChip(®), comparing LCA-hiPSCs derivatives to controls. A genomic search for alteration in all genes known to be involved in LCA revealed a common polymorphism on the GUCY2D gene, referenced as the LCA type I (OMIM *600179 and #204000), but the causative gene remained unknown. The hiPSCs expressed the key pluripotency factors and formed embryoid bodies in vitro containing cells originating from all three germ layers. They were successfully differentiated into NSC and RPE cells. One gene, NNAT, was upregulated in LCA cell populations, and three genes were downregulated, GSTT1, TRIM61 and ZNF558, with potential correlates for molecular mechanisms of this type of LCA, in particular for protein degradation and oxidative stress. The two LCA patient-specific iPSC lines will contribute to modeling LCA phenotypes and screening candidate drugs.
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21
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Corneal gene therapy: basic science and translational perspective. Ocul Surf 2013; 11:150-64. [PMID: 23838017 DOI: 10.1016/j.jtos.2012.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/21/2012] [Accepted: 12/01/2012] [Indexed: 11/20/2022]
Abstract
Corneal blindness is the third leading cause of blindness worldwide. Gene therapy is an emerging technology for corneal blindness due to the accessibility and immune-privileged nature of the cornea, ease of vector administration and visual monitoring, and ability to perform frequent noninvasive corneal assessment. Vision restoration by gene therapy is contingent upon vector and mode of therapeutic gene introduction into targeted cells/tissues. Numerous efficacious vectors, delivery techniques, and approaches have evolved in the last decade for developing gene-based interventions for corneal diseases. Maximizing the potential benefits of gene therapy requires efficient and sustained therapeutic gene expression in target cells, low toxicity, and a high safety profile. This review describes the basic science associated with many gene therapy vectors and the present progress of gene therapy carried out for various ocular surface disorders and diseases.
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22
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Targeting astrocytes ameliorates neurologic changes in a mouse model of Alzheimer's disease. J Neurosci 2013; 32:16129-40. [PMID: 23152597 DOI: 10.1523/jneurosci.2323-12.2012] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Astrocytes are the most abundant cell type in the brain and play a critical role in maintaining healthy nervous tissue. In Alzheimer's disease (AD) and most other neurodegenerative disorders, many astrocytes convert to a chronically "activated" phenotype characterized by morphologic and biochemical changes that appear to compromise protective properties and/or promote harmful neuroinflammatory processes. Activated astrocytes emerge early in the course of AD and become increasingly prominent as clinical and pathological symptoms progress, but few studies have tested the potential of astrocyte-targeted therapeutics in an intact animal model of AD. Here, we used adeno-associated virus (AAV) vectors containing the astrocyte-specific Gfa2 promoter to target hippocampal astrocytes in APP/PS1 mice. AAV-Gfa2 vectors drove the expression of VIVIT, a peptide that interferes with the immune/inflammatory calcineurin/NFAT (nuclear factor of activated T-cells) signaling pathway, shown by our laboratory and others to orchestrate biochemical cascades leading to astrocyte activation. After several months of treatment with Gfa2-VIVIT, APP/PS1 mice exhibited improved cognitive and synaptic function, reduced glial activation, and lower amyloid levels. The results confirm a deleterious role for activated astrocytes in AD and lay the groundwork for exploration of other novel astrocyte-based therapies.
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Katsanis N, Cotten M, Angrist M. Exome and genome sequencing of neonates with neurodevelopmental disorders. FUTURE NEUROLOGY 2012. [DOI: 10.2217/fnl.12.74] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Nicholas Katsanis
- Center for Human Disease Modeling, Duke University School of Medicine, Durham, NC 27710, USA
| | - Michael Cotten
- Department of Pediatrics, Division of Neonatology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Misha Angrist
- Institute for Genome Sciences & Policy, Duke University School of Medicine, Durham, NC 27710, USA
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Abstract
Parvoviruses package a ssDNA genome. Both nonpathogenic and pathogenic members exist, including those that cause fetal infections, encompassing the entire spectrum of virus phenotypes. Their small genomes and simple coding strategy has enabled functional annotation of many steps in the infectious life cycle. They assemble a multifunctional capsid responsible for cell recognition and the transport of the packaged genome to the nucleus for replication and progeny virus production. It is also the target of the host immune response. Understanding how the capsid structure relates to the function of parvoviruses provides a platform for recombinant engineering of viral gene delivery vectors for the treatment of clinical diseases, and is fundamental for dissecting the viral determinants of pathogenicity. This review focuses on our current understanding of parvovirus capsid structure and function with respect to the infectious life cycle.
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Affiliation(s)
- Sujata Halder
- Department of Biochemistry & Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, College of Medicine, 1600 SW Archer Road, PO Box 100245, University of Florida, Gainesville, FL 32610, USA
| | - Robert Ng
- Department of Biochemistry & Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, College of Medicine, 1600 SW Archer Road, PO Box 100245, University of Florida, Gainesville, FL 32610, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry & Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, College of Medicine, 1600 SW Archer Road, PO Box 100245, University of Florida, Gainesville, FL 32610, USA
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