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Venkatakrishnan J, Yuan Y, Zhang J, Yu Y, Hu YC, Kao WWY. Self-complementary AAV vector therapy for treating corneal cloudiness of mucopolysaccharidosis type VII (MPS VII). Ocul Surf 2024; 32:39-47. [PMID: 38218582 DOI: 10.1016/j.jtos.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 11/26/2023] [Accepted: 01/06/2024] [Indexed: 01/15/2024]
Abstract
PURPOSE To design a novel efficacious scAAV-Gusb viral vector for treating Mucopolysaccharidosis Type VII (MPS VII) caused by a mutation in the β-Glu gene (Gusb allele). METHODS β-Glu expression of single-stranded AAV-Gusb (ssAAV-Gusb) and self-complementary AAV (scAAV-Gusb) vectors are tested with cultured murine Gusb fibroblasts. The scAAV-Gusb vector was chosen in further studies to prolong the life span and treat corneal pathology of Gusb mice via intrahepatic injection of neonates and intrastromal injection in adults, respectively. Corneal pathology was studied using HRT2 in vivo confocal microscope and histochemistry in mice corneas. RESULTS Both ssAAV-Gusb and scAAV-Gusb vectors expressed murine β-Glu in cultured Gusb fibroblasts. The scAAV-Gusb vector had higher transduction efficiency than the ssAAV-Gusb vector. To prolong the life span of Gusb mice, neonates (3 days old) were administered with scAAV-Gusb virus via intrahepatic injection. The treatment improves the survival rate of Gusb mice, prolonging the median survival rate from 22.5 weeks (untreated) to 50 weeks (treated). Thereafter, we determined the efficacy of the scAAV-Gusb virus in ameliorating corneal cloudiness observed in aged Gusb mice. Both corneal cloudiness and stroma thickness decreased, and there was the presence of β-Glu enzyme activity in the Gusb corneas receiving scAAV-Gusb virus associated with morphology change of amoeboid stromal cells in untreated to characteristic dendritic keratocytes morphology after 4-12 weeks of scAAV-Gusb virus injection. CONCLUSION Intrahepatic injection of scAAV-Gusb is efficacious in prolonging the life span of Gusb mice, and intrastromal injection can ameliorate corneal phenotypes. Both strategies can be adapted for treating other MPS.
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Affiliation(s)
- Jhuwala Venkatakrishnan
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA; Department of Biomedical Engineering, University of Cincinnati, OH, USA
| | - Yong Yuan
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Jianhua Zhang
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yang Yu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, OH, USA
| | - Yueh-Chiang Hu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, OH, USA
| | - Winston W-Y Kao
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA.
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He X, Fu Y, Ma L, Yao Y, Ge S, Yang Z, Fan X. AAV for Gene Therapy in Ocular Diseases: Progress and Prospects. RESEARCH (WASHINGTON, D.C.) 2023; 6:0291. [PMID: 38188726 PMCID: PMC10768554 DOI: 10.34133/research.0291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 11/27/2023] [Indexed: 01/09/2024]
Abstract
Owing to the promising therapeutic effect and one-time treatment advantage, gene therapy may completely change the management of eye diseases, especially retinal diseases. Adeno-associated virus (AAV) is considered one of the most promising viral gene delivery tools because it can infect various types of tissues and is considered as a relatively safe gene delivery vector. The eye is one of the most popular organs for gene therapy, since its limited volume is suitable for small doses of AAV stably transduction. Recently, an increasing number of clinical trials of AAV-mediated gene therapy are underway. This review summarizes the biological functions of AAV and its application in the treatment of various ocular diseases, as well as the characteristics of different AAV delivery routes in clinical applications. Here, the latest research progresses in AAV-mediated gene editing and silencing strategies to modify that the genetic ocular diseases are systematically outlined, especially by base editing and prime editing. We discuss the progress of AAV in ocular optogenetic therapy. We also summarize the application of AAV-mediated gene therapy in animal models and the difficulties in its clinical transformation.
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Affiliation(s)
- Xiaoyu He
- Department of Ophthalmology, Ninth People’s Hospital,
Shanghai JiaoTong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
| | - Yidian Fu
- Department of Ophthalmology, Ninth People’s Hospital,
Shanghai JiaoTong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
| | - Liang Ma
- Department of Ophthalmology, Ninth People’s Hospital,
Shanghai JiaoTong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
| | - Yizheng Yao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University; Clinical Research Center of Neurological Disease,
The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Shengfang Ge
- Department of Ophthalmology, Ninth People’s Hospital,
Shanghai JiaoTong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
| | - Zhi Yang
- Department of Ophthalmology, Ninth People’s Hospital,
Shanghai JiaoTong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
| | - Xianqun Fan
- Department of Ophthalmology, Ninth People’s Hospital,
Shanghai JiaoTong University School of Medicine, Shanghai, China
- Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China
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3
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Dong F, Amlal H, Venkatakrishnan J, Zhang J, Fry M, Yuan Y, Cheng YC, Hu YC, Kao WWY. The gene therapy for corneal pathology with novel nonsense cystinosis mouse lines created by CRISPR Gene Editing. Ocul Surf 2023; 29:432-443. [PMID: 37355021 PMCID: PMC10725217 DOI: 10.1016/j.jtos.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/26/2023] [Accepted: 06/02/2023] [Indexed: 06/26/2023]
Abstract
PURPOSE Cystinosis is an autosomal recessive lysosomal storage disease (LSDs) caused by mutations in the gene encoding cystinosin (CTNS) that leads to cystine crystal accumulation in the lysosome that compromises cellular functions resulting in tissue damage and organ failure, especially in kidneys and eyes. However, the underlying molecular mechanism of its pathogenesis remains elusive. Two novel mice lines created via CRISPR are used to examine the pathogenesis of cystinosis in the kidney and cornea and the treatment efficacy of corneal pathology using self-complimentary Adeno-associated viral (scAAV-CTNS) vector. METHODS The CRISPR technique generated two novel cystinotic mouse lines, Ctnsis1 (an insertional mutation) and Ctnsis2 (a nonsense mutation). Immune histochemistry, renal functions test and HRT2 in vivo confocal microscopy were used to evaluate the age-related renal pathogenesis and treatment efficacy of the scAAV-CTNS virus in corneal pathology. RESULTS Both mutations lead to the production of truncated Ctns proteins. Ctnsis1 and Ctnsis 2 mice exhibit the characteristic of cystinotic corneal crystal phenotype at four-week-old. Treatment with the scAAV-CTNS viral vector decreased the corneal crystals in the treated mice cornea. Ctnsis 1 show renal abnormalities manifested by increased urine volume, reduced urine osmolality, and the loss of response to Desmopressin (dDAVP) at 22-month-old but Ctnsis2 don't manifest renal pathology up to 2 years of age. CONCLUSIONS Both Ctnsis1 and Ctnsis2 mice exhibit phenotypes resembling human intermediate nephropathic and ocular cystinosis, respectively. scAAV-CTNS viral vectors reduce the corneal cystine crystals and have a great potential as a therapeutic strategy for treating patients suffering from cystinosis.
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Affiliation(s)
- Fei Dong
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Hassane Amlal
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | | | - Jianhua Zhang
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Matthew Fry
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yong Yuan
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yu Chia Cheng
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yueh-Chiang Hu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Winston W-Y Kao
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA.
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4
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Chen J, Lin FL, Leung JYK, Tu L, Wang JH, Chuang YF, Li F, Shen HH, Dusting GJ, Wong VHY, Lisowski L, Hewitt AW, Bui BV, Zhong J, Liu GS. A drug-tunable Flt23k gene therapy for controlled intervention in retinal neovascularization. Angiogenesis 2021; 24:97-110. [PMID: 32935224 DOI: 10.1007/s10456-020-09745-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 09/04/2020] [Indexed: 12/15/2022]
Abstract
Gene therapies that chronically suppress vascular endothelial growth factor (VEGF) represent a new approach for managing retinal vascular leakage and neovascularization. However, constitutive suppression of VEGF in the eye may have deleterious side effects. Here, we developed a novel strategy to introduce Flt23k, a decoy receptor that binds intracellular VEGF, fused to the destabilizing domain (DD) of Escherichia coli dihydrofolate reductase (DHFR) into the retina. The expressed DHFR(DD)-Flt23k fusion protein is degraded unless "switched on" by administering a stabilizer; in this case, the antibiotic trimethoprim (TMP). Cells transfected with the DHFR(DD)-Flt23k construct expressed the fusion protein at levels correlated with the TMP dose. Stabilization of the DHFR(DD)-Flt23k fusion protein by TMP was able to inhibit intracellular VEGF in hypoxic cells. Intravitreal injection of self-complementary adeno-associated viral vector (scAAV)-DHFR(DD)-Flt23k and subsequent administration of TMP resulted in tunable suppression of ischemia-induced retinal neovascularization in a rat model of oxygen-induced retinopathy (OIR). Hence, our study suggests a promising novel approach for the treatment of retinal neovascularization. Schematic diagram of the tunable system utilizing the DHFR(DD)-Flt23k approach to reduce VEGF secretion. a The schematic shows normal VEGF secretion. b Without the ligand TMP, the DHFR(DD)-Flt23k protein is destabilized and degraded by the proteasome. c In the presence of the ligand TMP, DHFR(DD)-Flt23k is stabilized and sequestered in the ER, thereby conditionally inhibiting VEGF. Green lines indicate the intracellular and extracellular distributions of VEGF. Blue lines indicate proteasomal degradation of the DHFR(DD)-Flt23k protein. Orange lines indicate the uptake of cell-permeable TMP. TMP, trimethoprim; VEGF, vascular endothelial growth factor; ER, endoplasmic reticulum.
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Affiliation(s)
- Jinying Chen
- Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Fan-Li Lin
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Jacqueline Y K Leung
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | - Leilei Tu
- Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Yu-Fan Chuang
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS, Australia
| | - Fan Li
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Hsin-Hui Shen
- Department of Materials Science and Engineering, Faculty of Engineering, Monash University, Clayton, VIC, Australia
- Department of Biochemistry and Molecular Biology, School of Biomedical Science, Monash University, Clayton, VIC, Australia
| | - Gregory J Dusting
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Leszek Lisowski
- Translational Vectorology Group, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- Vector and Genome Engineering Facility, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
- Military Institute of Hygiene and Epidemiology, The Biological Threats Identification and Countermeasure Centre, Puławy, Poland
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Jingxiang Zhong
- Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China
| | - Guei-Sheung Liu
- Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong, China.
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia.
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia.
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5
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Mohan RR, Martin LM, Sinha NR. Novel insights into gene therapy in the cornea. Exp Eye Res 2020; 202:108361. [PMID: 33212142 DOI: 10.1016/j.exer.2020.108361] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/17/2022]
Abstract
Corneal disease remains a leading cause of impaired vision world-wide, and advancements in gene therapy continue to develop with promising success to prevent, treat and cure blindness. Ideally, gene therapy requires a vector and gene delivery method that targets treatment of specific cells or tissues and results in a safe and non-immunogenic response. The cornea is a model tissue for gene therapy due to its ease of clinician access and immune-privileged state. Improvements in the past 5-10 years have begun to revolutionize the approach to gene therapy in the cornea with a focus on adeno-associated virus and nanoparticle delivery of single and combination gene therapies. In addition, the potential applications of gene editing (zinc finger nucleases [ZNFs], transcription activator-like effector nucleases [TALENs], Clustered Regularly Interspaced Short Palindromic Repeats/Associated Systems [CRISPR/Cas9]) are rapidly expanding. This review focuses on recent developments in gene therapy for corneal diseases, including promising multiple gene therapy, while outlining a practical approach to the development of such therapies and potential impediments to successful delivery of genes to the cornea.
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Affiliation(s)
- Rajiv R Mohan
- Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, United States; One-health Vision Research Center, Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, United States; Mason Eye Institute, School of Medicine, University of Missouri, Columbia, MO, United States.
| | - Lynn M Martin
- Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, United States; One-health Vision Research Center, Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, United States
| | - Nishant R Sinha
- Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, United States; One-health Vision Research Center, Departments of Veterinary Medicine & Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, United States
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6
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Greenwald SH, Brown EE, Scandura MJ, Hennessey E, Farmer R, Pawlyk BS, Xiao R, Vandenberghe LH, Pierce EA. Gene Therapy Preserves Retinal Structure and Function in a Mouse Model of NMNAT1-Associated Retinal Degeneration. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 18:582-594. [PMID: 32775493 PMCID: PMC7397406 DOI: 10.1016/j.omtm.2020.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022]
Abstract
No treatment is available for nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1)-associated retinal degeneration, an inherited disease that leads to severe vision loss early in life. Although the causative gene, NMNAT1, plays an essential role in nuclear nicotinamide adenine dinucleotide (NAD)+ metabolism in tissues throughout the body, NMNAT1-associated disease is isolated to the retina. Since this condition is recessive, supplementing the retina with a normal copy of NMNAT1 should protect vulnerable cells from disease progression. We tested this hypothesis in a mouse model that harbors the p.Val9Met mutation in Nmnat1 and consequently develops a retinal degenerative phenotype that recapitulates key features of the human disease. Gene augmentation therapy, delivered by subretinal injection of adeno-associated virus (AAV) carrying a normal human copy of NMNAT1, rescued retinal structure and function. Due to the early-onset profile of the phenotype, a rapidly activating self-complementary AAV was required to initiate transgene expression during the narrow therapeutic window. These data represent the first proof of concept for a therapy to treat patients with NMNAT1-associated disease.
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Affiliation(s)
- Scott H Greenwald
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Emily E Brown
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Michael J Scandura
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Erin Hennessey
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Raymond Farmer
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Basil S Pawlyk
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Ru Xiao
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Ocular Genomics Institute, Grousebeck Gene Therapy Center, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Luk H Vandenberghe
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA.,Ocular Genomics Institute, Grousebeck Gene Therapy Center, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
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7
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Buck TM, Wijnholds J. Recombinant Adeno-Associated Viral Vectors (rAAV)-Vector Elements in Ocular Gene Therapy Clinical Trials and Transgene Expression and Bioactivity Assays. Int J Mol Sci 2020; 21:E4197. [PMID: 32545533 PMCID: PMC7352801 DOI: 10.3390/ijms21124197] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
Inherited retinal dystrophies and optic neuropathies cause chronic disabling loss of visual function. The development of recombinant adeno-associated viral vectors (rAAV) gene therapies in all disease fields have been promising, but the translation to the clinic has been slow. The safety and efficacy profiles of rAAV are linked to the dose of applied vectors. DNA changes in the rAAV gene cassette affect potency, the expression pattern (cell-specificity), and the production yield. Here, we present a library of rAAV vectors and elements that provide a workflow to design novel vectors. We first performed a meta-analysis on recombinant rAAV elements in clinical trials (2007-2020) for ocular gene therapies. We analyzed 33 unique rAAV gene cassettes used in 57 ocular clinical trials. The rAAV gene therapy vectors used six unique capsid variants, 16 different promoters, and six unique polyadenylation sequences. Further, we compiled a list of promoters, enhancers, and other sequences used in current rAAV gene cassettes in preclinical studies. Then, we give an update on pro-viral plasmid backbones used to produce the gene therapy vectors, inverted terminal repeats, production yield, and rAAV safety considerations. Finally, we assess rAAV transgene and bioactivity assays applied to cells or organoids in vitro, explants ex vivo, and clinical studies.
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Affiliation(s)
- Thilo M. Buck
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, The Netherlands;
| | - Jan Wijnholds
- Department of Ophthalmology, Leiden University Medical Center (LUMC), 2333 ZC Leiden, The Netherlands;
- Netherlands Institute of Neuroscience, Royal Netherlands Academy of Arts and Sciences (KNAW), 1105 BA Amsterdam, The Netherlands
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8
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Khabou H, Cordeau C, Pacot L, Fisson S, Dalkara D. Dosage Thresholds and Influence of Transgene Cassette in Adeno-Associated Virus-Related Toxicity. Hum Gene Ther 2018; 29:1235-1241. [PMID: 30132368 DOI: 10.1089/hum.2018.144] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Today, there are >500 published studies and 40 clinical trials to treat retinal disorders using gene therapy. The great majority of them rely on the use of adeno-associated virus vectors (AAV) for therapeutic gene delivery. Thus far, AAVs have an excellent safety profile in the clinic. Nevertheless, it is known that AAV-mediated gene delivery leads to toxicity at higher input doses in experimental gene therapy. This study reveals the factors that contribute to retinal toxicity after subretinal administration of AAV vectors in wild-type mice. The study shows that alongside the input dose, the nature of the transgene and the cells mediating the expression determine the extent of toxicity. Importantly, the study shows that AAV vectors encoding green fluorescent protein (GFP) used as controls in experimental gene therapy are toxic at doses as low as 5 × 109 vg, confounding the observed therapeutic effect in gene therapy paradigms. Altogether, the data show the importance of reducing input doses while increasing transgene expression levels via the use of more efficient capsids and promoters in order to avoid side effects in AAV-mediated gene therapy. Furthermore, the toxicity observed with AAV-GFP vectors imply a reinterpretation of previous gene therapy studies where the therapeutic effect was measured in relation to this control.
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Affiliation(s)
- Hanen Khabou
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Chloé Cordeau
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Laure Pacot
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Sylvain Fisson
- 2 Généthon, Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
| | - Deniz Dalkara
- 1 Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision , Paris, France; and Inserm UMR_S951, Univ Evry, Université Paris-Saclay, EPHE, Evry, France
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9
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Bee YS, Tu L, Sheu SJ, Lin HC, Tang JH, Wang JH, Prea SM, Dusting GJ, Wu DC, Zhong J, Bui BV, Tai MH, Liu GS. Gene Delivery of Calreticulin Anti-Angiogenic Domain Attenuates the Development of Choroidal Neovascularization in Rats. Hum Gene Ther 2017; 28:403-414. [DOI: 10.1089/hum.2016.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Youn-Shen Bee
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- Yuh-Ing Junior College of Health Care and Management, Kaohsiung, Taiwan
- National Defense Medical Center, Taipei, Taiwan
| | - Leilei Tu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shwu-Jiuan Sheu
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Hsiu-Chen Lin
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Jia-Hua Tang
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Australia
| | - Selwyn M. Prea
- Department of Optometry and Vision Sciences, University of Melbourne, East Melbourne, Australia
| | - Gregory J. Dusting
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Australia
| | - Deng-Chyang Wu
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jingxiang Zhong
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, University of Melbourne, East Melbourne, Australia
| | - Ming-Hong Tai
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
- Center for Neuroscience, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Guei-Sheung Liu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Australia
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10
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De Silva SR, Charbel Issa P, Singh MS, Lipinski DM, Barnea-Cramer AO, Walker NJ, Barnard AR, Hankins MW, MacLaren RE. Single residue AAV capsid mutation improves transduction of photoreceptors in the Abca4 -/- mouse and bipolar cells in the rd1 mouse and human retina ex vivo. Gene Ther 2016; 23:767-774. [PMID: 27416076 PMCID: PMC5097463 DOI: 10.1038/gt.2016.54] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 04/12/2016] [Accepted: 04/20/2016] [Indexed: 02/08/2023]
Abstract
Gene therapy using adeno-associated viral (AAV) vectors for the treatment of retinal degenerations has shown safety and efficacy in clinical trials. However, very high levels of vector expression may be necessary for the treatment of conditions such as Stargardt disease where a dual vector approach is potentially needed, or in optogenetic strategies for end-stage degeneration in order to achieve maximal light sensitivity. In this study, we assessed two vectors with single capsid mutations, rAAV2/2(Y444F) and rAAV2/8(Y733F) in their ability to transduce retina in the Abca4-/- and rd1 mouse models of retinal degeneration. We noted significantly increased photoreceptor transduction using rAAV2/8(Y733F) in the Abca4-/- mouse, in contrast to previous work where vectors tested in this model have shown low levels of photoreceptor transduction. Bipolar cell transduction was achieved following subretinal delivery of both vectors in the rd1 mouse, and via intravitreal delivery of rAAV2/2(Y444F). The successful use of rAAV2/8(Y733F) to target bipolar cells was further validated on human tissue using an ex vivo culture system of retinal explants. Capsid mutant AAV vectors transduce human retinal cells and may be particularly suited to treat retinal degenerations in which high levels of transgene expression are required.
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Affiliation(s)
- Samantha R De Silva
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Peter Charbel Issa
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Mandeep S Singh
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Daniel M Lipinski
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Alona O Barnea-Cramer
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Nathan J Walker
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Mark W Hankins
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, NIHR Biomedical Research Centre, UK
- Moorfields Eye Hospital, NIHR Biomedical Research Centre, UK
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Heparan Sulfate Binding Promotes Accumulation of Intravitreally Delivered Adeno-associated Viral Vectors at the Retina for Enhanced Transduction but Weakly Influences Tropism. J Virol 2016; 90:9878-9888. [PMID: 27558418 DOI: 10.1128/jvi.01568-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/15/2016] [Indexed: 12/20/2022] Open
Abstract
Many adeno-associated virus (AAV) serotypes efficiently transduce the retina when delivered to the subretinal space but show limited success when delivered to the vitreous due to the inner limiting membrane (ILM). Subretinal delivery of AAV serotype 2 (AAV2) and its heparan sulfate (HS)-binding-deficient capsid led to similar expression, indicating transduction of the outer retina occurred by HS-independent mechanisms. However, intravitreal delivery of HS-ablated recombinant AAV2 (rAAV2) led to a 300-fold decrease in transduction compared to AAV2. Fluorescence in situ hybridization of AAV transgenes was used to identify differences in retinal trafficking and revealed that HS binding was responsible for AAV2 accumulation at the ILM. This mechanism was tested on human ex vivo retinas and showed similar accumulation with HS-binding AAV2 capsid only. To evaluate if HS binding could be applied to other AAV serotypes to enhance their transduction, AAV1 and AAV8 were modified to bind HS with a single-amino-acid mutation and tested in mice. Both HS-binding mutants of AAV1 and AAV8 had higher intravitreal transduction than their non-HS-binding parent capsid due to increased retinal accumulation. To understand the influence that HS binding has on tropism, chimeric AAV2 capsids with dual-glycan usage were tested intravitreally in mice. Compared to HS binding alone, these chimeric capsids displayed enhanced transduction that was correlated with a change in tropism. Taken together, these data indicate that HS binding serves to sequester AAV capsids from the vitreous to the ILM but does not influence retinal tropism. The enhanced retinal transduction of HS-binding capsids provides a rational design strategy for engineering capsids for intravitreal delivery. IMPORTANCE Adeno-associated virus (AAV) has become the vector of choice for viral gene transfer and has shown great promise in clinical trials. The need for development of an easy, less invasive injection route for ocular gene therapy is met by intravitreal delivery, but delivery of AAV by this route results in poor transduction outcomes. The inner limiting membrane (ILM) creates a barrier separating the vitreous and the retina. Binding of AAV to heparan sulfate proteoglycan (HSPG) at the ILM may allow the virus to traverse this barrier for better retinal transduction. We show that HSPG binding is correlated with greater accumulation and penetration of AAV in the retina. We demonstrated that this accumulation is conserved across mouse and human retinas and that the addition of HSPG binding to other AAV capsids can increase the number of vectors accumulating at the ILM without dictating tropism.
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12
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Self-Complementary Adeno-Associated Virus Vectors Improve Transduction Efficiency of Corneal Endothelial Cells. PLoS One 2016; 11:e0152589. [PMID: 27023329 PMCID: PMC4811580 DOI: 10.1371/journal.pone.0152589] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/16/2016] [Indexed: 12/13/2022] Open
Abstract
Transplantation of a donor cornea to restore vision is the most frequently performed transplantation in the world. Corneal endothelial cells (CEC) are crucial for the outcome of a graft as they maintain corneal transparency and avoid graft failure due to corneal opaqueness. Given the characteristic of being a monolayer and in direct contact with culture medium during cultivation in eye banks, CEC are specifically suitable for gene therapeutic approaches prior to transplantation. Recombinant adeno-associated virus 2 (rAAV2) vectors represent a promising tool for gene therapy of CEC. However, high vector titers are needed to achieve sufficient gene expression. One of the rate-limiting steps for transgene expression is the conversion of single-stranded (ss-) DNA vector genome into double-stranded (ds-) DNA. This step can be bypassed by using self-complementary (sc-) AAV2 vectors. Aim of this study was to compare for the first time transduction efficiencies of ss- and scAAV2 vectors in CEC. For this purpose AAV2 vectors containing enhanced green fluorescent protein (GFP) as transgene were used. Both in CEC and in donor corneas, transduction with scAAV2 resulted in significantly higher transgene expression compared to ssAAV2. The difference in transduction efficiency decreased with increasing vector titer. In most cases, only half the vector titer of scAAV2 was required for equal or higher gene expression rates than those of ssAAV2. In human donor corneas, GFP expression was 64.7±11.3% (scAAV) and 38.0±8.6% (ssAAV) (p<0.001), respectively. Furthermore, transduced cells maintained their viability and showed regular morphology. Working together with regulatory authorities, a translation of AAV2 vector-mediated gene therapy to achieve a temporary protection of corneal allografts during cultivation and transplantation could therefore become more realistic.
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Mookherjee S, Hiriyanna S, Kaneshiro K, Li L, Li Y, Li W, Qian H, Li T, Khanna H, Colosi P, Swaroop A, Wu Z. Long-term rescue of cone photoreceptor degeneration in retinitis pigmentosa 2 (RP2)-knockout mice by gene replacement therapy. Hum Mol Genet 2015; 24:6446-58. [PMID: 26358772 DOI: 10.1093/hmg/ddv354] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/01/2015] [Indexed: 11/14/2022] Open
Abstract
Retinal neurodegenerative diseases are especially attractive targets for gene replacement therapy, which appears to be clinically effective for several monogenic diseases. X-linked forms of retinitis pigmentosa (XLRP) are relatively severe blinding disorders, resulting from progressive photoreceptor dysfunction primarily caused by mutations in RPGR or RP2 gene. With a goal to develop gene therapy for the XLRP-RP2 disease, we first performed detailed characterization of the Rp2-knockout (Rp2-KO) mice and observed early-onset cone dysfunction, which was followed by progressive cone degeneration, mimicking cone vision impairment in XLRP patients. The mice also exhibited distinct and significantly delayed falling phase of photopic b-wave of electroretinogram (ERG). Concurrently, we generated a self-complementary adeno-associated viral (AAV) vector carrying human RP2-coding sequence and demonstrated its ability to mediate stable RP2 protein expression in mouse photoreceptors. A long-term efficacy study was then conducted in Rp2-KO mice following AAV-RP2 vector administration. Preservation of cone function was achieved with a wide dose range over 18-month duration, as evidenced by photopic ERG and optomotor tests. The slower b-wave kinetics was also completely restored. Morphologically, the treatment preserved cone viability, corrected mis-trafficking of M-cone opsin and restored cone PDE6 expression. The therapeutic effect was achieved even in mice that received treatment at an advanced disease stage. The highest AAV-RP2 dose group demonstrated retinal toxicity, highlighting the importance of careful vector dosing in designing future human trials. The wide range of effective dose, a broad treatment window and long-lasting therapeutic effects should make the RP2 gene therapy attractive for clinical development.
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Affiliation(s)
| | - Suja Hiriyanna
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Kayleigh Kaneshiro
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Linjing Li
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Yichao Li
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Wei Li
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Haohua Qian
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Tiansen Li
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Hemant Khanna
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Peter Colosi
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Anand Swaroop
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
| | - Zhijian Wu
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA and
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14
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Retinal gene delivery by adeno-associated virus (AAV) vectors: Strategies and applications. Eur J Pharm Biopharm 2015; 95:343-52. [DOI: 10.1016/j.ejpb.2015.01.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/10/2015] [Accepted: 01/12/2015] [Indexed: 11/20/2022]
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15
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de Silva SR, McClements ME, Hankins MW, MacLaren RE. Adeno-Associated Viral Gene Therapy for Retinal Disorders. NEUROMETHODS 2015. [DOI: 10.1007/978-1-4939-2306-9_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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16
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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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Takahashi Y, Moiseyev G, Ma JX. Identification of key residues determining isomerohydrolase activity of human RPE65. J Biol Chem 2014; 289:26743-26751. [PMID: 25112876 DOI: 10.1074/jbc.m114.558619] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
RPE65 is the retinoid isomerohydrolase that converts all-trans-retinyl ester to 11-cis-retinol, a key reaction in the retinoid visual cycle. We have previously reported that cone-dominant chicken RPE65 (cRPE65) shares 90% sequence identity with human RPE65 (hRPE65) but exhibits substantially higher isomerohydrolase activity than that of bovine RPE65 or hRPE65. In this study, we sought to identify key residues responsible for the higher enzymatic activity of cRPE65. Based on the amino acid sequence comparison of mammalian and other lower vertebrates' RPE65, including cone-dominant chicken, 8 residues of hRPE65 were separately replaced by their counterparts of cRPE65 using site-directed mutagenesis. The enzymatic activities of cRPE65, hRPE65, and its mutants were measured by in vitro isomerohydrolase activity assay, and the retinoid products were analyzed by HPLC. Among the mutants analyzed, two single point mutants, N170K and K297G, and a double mutant, N170K/K297G, of hRPE65 exhibited significantly higher catalytic activity than WT hRPE65. Further, when an amino-terminal fragment (Met(1)-Arg(33)) of the N170K/K297G double mutant of hRPE65 was replaced with the corresponding cRPE65 fragment, the isomerohydrolase activity was further increased to a level similar to that of cRPE65. This finding contributes to the understanding of the structural basis for isomerohydrolase activity. This highly efficient human isomerohydrolase mutant can be used to improve the efficacy of RPE65 gene therapy for retinal degeneration caused by RPE65 mutations.
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Affiliation(s)
- Yusuke Takahashi
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Gennadiy Moiseyev
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Department of Physiology, and University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Jian-Xing Ma
- Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104; Department of Physiology, and University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
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Colella P, Auricchio A. Gene therapy of inherited retinopathies: a long and successful road from viral vectors to patients. Hum Gene Ther 2013; 23:796-807. [PMID: 22734691 DOI: 10.1089/hum.2012.123] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Inherited retinopathies (IRs) are common and untreatable blinding conditions inherited mostly as monogenic due to mutations in genes expressed in retinal photoreceptors (PRs) and in retinal pigment epithelium (RPE). Over the last two decades, the retina has emerged as one of the most favorable target tissues for gene therapy given its small size and its enclosed and immune-privileged environment. Different types of viral vectors have been developed, especially those based on the adeno-associated virus (AAV), which efficiently deliver therapeutic genes to PRs or RPE upon subretinal injections. Dozens of successful proofs of concept of the efficacy of gene therapy for recessive and dominant IRs have been generated in small and large models that have paved the way to the first clinical trials using AAV in patients with Leber congenital amaurosis, a severe form of childhood blindness. The results from these initial trials suggest that retinal gene therapy with AAV is safe in humans, that vision can be improved in patients that have suffered from severe impairment of visual function, in some cases for decades, and that readministration of AAV to the subretinal space is feasible, effective, and safe. However, none of the trials could match the levels of efficacy of gene therapy observed in a dog model of the disease, suggesting that there is room for improvement. In conclusion, these results bode well for further testing of AAV-mediated retinal gene therapy in patients with other monogenic and complex forms of blindness.
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Askou AL, Pournaras JAC, Pihlmann M, Svalgaard JD, Arsenijevic Y, Kostic C, Bek T, Dagnaes-Hansen F, Mikkelsen JG, Jensen TG, Corydon TJ. Reduction of choroidal neovascularization in mice by adeno-associated virus-delivered anti-vascular endothelial growth factor short hairpin RNA. J Gene Med 2013; 14:632-41. [PMID: 23080553 DOI: 10.1002/jgm.2678] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/04/2012] [Accepted: 10/15/2012] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Strategies leading to the long-term suppression of inappropriate ocular angiogenesis are required to avoid the need for repetitive monthly injections for treatment of diseases of the eye, such as age-related macular degeneration (AMD). The present study aimed to develop a strategy for the sustained repression of vascular endothelial growth factor (VEGF), which is identified as the key player in exudative AMD. METHODS We have employed short hairpin (sh)RNAs combined with adeno-associated virus (AAV) delivery to obtain the targeted expression of potent gene-regulatory molecules. Anti-VEGF shRNAs were analyzed in human retinal pigment epithelial (RPE) cells using Renilla luciferase screening. For in vivo delivery of the most potent shRNA, self-complementary AAV vectors were packaged in serotype 8 capsids (scAAV2/8-hU6-sh9). In vivo efficacy was evaluated either by injection of scAAV2/8-hU6-sh9 into murine hind limb muscles or in a laser-induced murine model of choroidal neovascularization (CNV) following scAAV2/8-hU6-sh9 subretinal delivery. RESULTS Plasmids encoding anti-VEGF shRNAs showed efficient knockdown of human VEGF in RPEs. Intramuscular administration led to localized expression and 91% knockdown of endogenous murine (m)VEGF. Subsequently, the ability of AAV2/8-encoded shRNAs to impair vessel formation was evaluated in the murine model of CNV. In this model, the sizes of the CNV were significantly reduced (up to 48%) following scAAV2/8-hU6-sh9 subretinal delivery. CONCLUSIONS Using anti-VEGF vectors, we have demonstrated efficient silencing of endogenous mVEGF and showed that subretinal administration of scAAV2/8-hU6-sh9 has the ability to impair vessel formation in an AMD animal model. Thus, AAV-encoded shRNA can be used for the inhibition of neovascularization, leading to the development of sustained anti-VEGF therapy.
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20
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McClements ME, MacLaren RE. Gene therapy for retinal disease. Transl Res 2013; 161:241-54. [PMID: 23305707 PMCID: PMC3831157 DOI: 10.1016/j.trsl.2012.12.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/12/2012] [Accepted: 12/13/2012] [Indexed: 01/16/2023]
Abstract
Gene therapy strategies for the treatment of inherited retinal diseases have made major advances in recent years. This review focuses on adeno-associated viral (AAV) vector approaches to treat retinal degeneration and, thus, prevent or delay the onset of blindness. Data from human clinical trials of gene therapy for retinal disease show encouraging signs of safety and efficacy from AAV vectors. Recent progress in enhancing cell-specific targeting and transduction efficiency of the various retinal layers plus the use of AAV-delivered growth factors to augment the therapeutic effect and limit cell death suggest even greater success in future human trials is possible.
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Affiliation(s)
- Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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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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Lipinski DM, Thake M, MacLaren RE. Clinical applications of retinal gene therapy. Prog Retin Eye Res 2013; 32:22-47. [DOI: 10.1016/j.preteyeres.2012.09.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 09/04/2012] [Accepted: 09/04/2012] [Indexed: 02/08/2023]
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Hellström M, Pollett MA, Harvey AR. Post-injury delivery of rAAV2-CNTF combined with short-term pharmacotherapy is neuroprotective and promotes extensive axonal regeneration after optic nerve trauma. J Neurotrauma 2012; 28:2475-83. [PMID: 21861632 DOI: 10.1089/neu.2011.1928] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recombinant adeno-associated viral (rAAV) vectors expressing neurotrophic genes reduce neuronal death and promote axonal regeneration in central nervous system (CNS) injury models. Currently, however, use of rAAV to treat clinical neurotrauma is problematic because there is a delay in the onset of transgene expression. Using the adult rat retina and optic nerve (ON), we have tested whether rAAV gene therapy administered at the time of injury combined with short-term pharmacotherapy has synergistic effects that enhance neuronal survival and regeneration. The ON was transected and a 1.5 cm segment of autologous peripheral nerve (PN) was grafted onto the cut end. At this time, bicistronic rAAV2 encoding ciliary neurotrophic factor (CNTF) and green fluorescent protein (rAAV2-CNTF-GFP) was injected into the injured eye. To provide interim support for axotomized retinal ganglion cells (RGCs) during vector integration and therapeutic transgene expression, rCNTF protein and a cyclic adenosine monophosphate (cAMP) analogue (CPT-cAMP) were injected intravitreally 3 and 10 days postoperatively. For comparison, another rAAV2-CNTF-GFP group received two intravitreal saline injections 3 and 10 days after the PN-ON surgery. A further PN graft group received only postoperative intravitreal injections of rCNTF plus CPT-cAMP. After 4 weeks, regenerating RGCs were retrogradely labelled by applying fluorogold to the distal end of each PN graft. Compared to saline-injected animals, both RGC survival and axonal regrowth were significantly higher in the rCNTF and CPT-cAMP injected rAAV2-CNTF-GFP group; approximately one third of the RGC population survived axotomy, and 27% of these regrew an axon. These values were also higher than those obtained in rats that received only rCNTF plus CPT-cAMP injections. Therefore, we show for the first time that rAAV-mediated gene delivery at the time of, or just after, neurotrauma is most successful when combined with temporary post-injury trophic support, and is potentially a viable treatment strategy for patients after acute CNS injury.
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Affiliation(s)
- Mats Hellström
- School of Anatomy and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
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Abstract
Clinical trials are currently underway using gene therapy to treat retinal disease such as Leber congenital amaurosis (LCA). Viral vectors that have been utilized to target retinal cells include adenoviruses, lentiviruses, and recombinant adeno-associated viruses (rAAV). Of the three classes, rAAV vectors show the greatest promise for retinal gene therapy. Recent developments in virus technology such as the development of hybrid and capsid mutant rAAV vectors mean that specific retinal cells can be targeted and faster stronger transgene expression is now possible compared to that achieved with the first generation of vectors. Gene therapy trials in dogs have been very important in the development of therapy for RPE65 LCA which is currently in phase I/II clinical trials in humans. Recent successes in using gene therapy to treat canine achromatopsia, X-linked progressive retinal atrophy (PRA) and the more severe rapid degenerations such as rod-cone dysplasia type 3 may lead also to the translation to human clinical trials. Dogs have played and continue to play an important role as animal models for proof-of-concept studies of retinal gene therapy. As modifications and improvements in gene therapy protocols are made from experience gathered from human clinical trials perhaps gene therapy for the treatment of canine clinical patients will become available to veterinary ophthalmologists.
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Affiliation(s)
- Simon M Petersen-Jones
- Veterinary Medical Center, Michigan State University, 736 Wilson Road, D-208, East Lansing, MI 48824, USA.
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Zarbin MA, Montemagno C, Leary JF, Ritch R. Regenerative nanomedicine and the treatment of degenerative retinal diseases. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2011; 4:113-37. [DOI: 10.1002/wnan.167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Marco A. Zarbin
- Institute of Ophthalmology and Visual Science, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | - Carlo Montemagno
- College of Engineering, University of Cincinnati, Cincinnati, OH, USA
| | - James F. Leary
- Department of Basic Medical Sciences, Purdue University, West Lafayette, IN Purdue University, School of Veterinary Medicine, West Lafayette, IN, USA
| | - Robert Ritch
- Einhorn Clinical Research Center, New York Eye & Ear Infirmary, New York, NY, USA
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Raj D, Davidoff AM, Nathwani AC. Self-complementary adeno-associated viral vectors for gene therapy of hemophilia B: progress and challenges. Expert Rev Hematol 2011; 4:539-49. [PMID: 21939421 PMCID: PMC3200187 DOI: 10.1586/ehm.11.48] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Therapies currently used for hemophilia involve injection of protein concentrates that are expensive, invasive and associated with side effects such as development of neutralizing antibodies (inhibitors) that diminish therapeutic efficacy. Gene transfer is an attractive alternative to circumvent these issues. However, until now, clinical trials using gene therapy to treat hemophilia have failed to demonstrate sustained efficacy, although a vector based on a self-complementary adeno-associated virus has recently shown promise. This article will briefly outline a novel gene-transfer approach using self-complementary adeno-associated viral vectors using hemophilia B as a target disorder. This approach is currently being evaluated in the clinic. We will provide an overview of the development of self-complementary adeno-associated virus vectors as well as preclinical and clinical data with this vector system.
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Affiliation(s)
- Deepak Raj
- Department of Haematology, University College London Cancer Institute, London, UK
| | - Andrew M Davidoff
- Department of Surgery, St Jude Children’s Research Hospital, Memphis, TN, USA
- Departments of Surgery and Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Amit C Nathwani
- Department of Haematology, University College London Cancer Institute, London, UK
- NHS Blood and Transplant, London, UK
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Rahim AA, Wong AMS, Hoefer K, Buckley SMK, Mattar CN, Cheng SH, Chan JKY, Cooper JD, Waddington SN. Intravenous administration of AAV2/9 to the fetal and neonatal mouse leads to differential targeting of CNS cell types and extensive transduction of the nervous system. FASEB J 2011; 25:3505-18. [DOI: 10.1096/fj.11-182311] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ahad A. Rahim
- Gene Transfer Technology Group, Institute for Women's HealthUniversity College London London UK
| | - Andrew M. S. Wong
- Pediatric Storage Disorders LaboratoryInstitute of Psychiatry, King's College London London UK
| | - Klemens Hoefer
- Pediatric Storage Disorders LaboratoryInstitute of Psychiatry, King's College London London UK
| | - Suzanne M. K. Buckley
- Gene Transfer Technology Group, Institute for Women's HealthUniversity College London London UK
| | - Citra N. Mattar
- Experimental Fetal Medicine Group, Department of Obstetrics and GynaecologyNational University of Singapore Singapore
| | | | - Jerry K. Y. Chan
- Experimental Fetal Medicine Group, Department of Obstetrics and GynaecologyNational University of Singapore Singapore
- Department of Reproductive MedicineKandang Kerbau Women's and Children's Hospital Singapore
| | - Jonathan D. Cooper
- Pediatric Storage Disorders LaboratoryInstitute of Psychiatry, King's College London London UK
| | - Simon N. Waddington
- Gene Transfer Technology Group, Institute for Women's HealthUniversity College London London UK
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28
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AAV mediated GDNF secretion from retinal glia slows down retinal degeneration in a rat model of retinitis pigmentosa. Mol Ther 2011; 19:1602-8. [PMID: 21522134 DOI: 10.1038/mt.2011.62] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mutations in over 80 identified genes can induce apoptosis in photoreceptors, resulting in blindness with a prevalence of 1 in 3,000 individuals. This broad genetic heterogeneity of disease impacting a wide range of photoreceptor functions renders the design of gene-specific therapies for photoreceptor degeneration impractical and necessitates the development of mutation-independent treatments to slow photoreceptor cell death. One promising strategy for photoreceptor neuroprotection is neurotrophin secretion from Müller cells, the primary retinal glia. Müller glia are excellent targets for secreting neurotrophins as they span the entire tissue, ensheath all neuronal populations, are numerous, and persist through retinal degeneration. We previously engineered an adeno-associated virus (AAV) variant (ShH10) capable of efficient and selective glial cell transduction through intravitreal injection. ShH10-mediated glial-derived neurotrophic factor (GDNF) secretion from glia, generates high GDNF levels in treated retinas, leading to sustained functional rescue for over 5 months. This GDNF secretion from glia following intravitreal vector administration is a safe and effective means to slow the progression of retinal degeneration in a rat model of retinitis pigmentosa (RP) and shows significant promise as a gene therapy to treat human retinal degenerations. These findings also demonstrate for the first time that glia-mediated secretion of neurotrophins is a promising treatment that may be applicable to other neurodegenerative conditions.
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Koilkonda RD, Chou TH, Porciatti V, Hauswirth WW, Guy J. Induction of rapid and highly efficient expression of the human ND4 complex I subunit in the mouse visual system by self-complementary adeno-associated virus. ACTA ACUST UNITED AC 2010; 128:876-83. [PMID: 20625049 DOI: 10.1001/archophthalmol.2010.135] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To demonstrate the high efficiency and rapidity of allotopic expression of a normal human ND4 subunit of complex I in the vertebrate retina using a self-complementary adeno-associated virus (scAAV) vector for ocular gene delivery to treat acute visual loss in Leber hereditary optic neuropathy (LHON). METHODS The nuclear-encoded human ND4 subunit fused to the P1 isoform of subunit C of adenosine triphosphate synthase (ATPc) mitochondrial targeting sequence and FLAG epitope was packaged in scAAV2 capsids or single-stranded (ss) AAV2 capsids. These constructs were injected into the vitreous cavities of mice. The contralateral eyes were injected with scAAV-green fluorescent protein (GFP). One week later, pattern electroretinograms and gene expression of the human ND4 subunit and GFP were evaluated. Quantitative analysis of ND4FLAG-injected eyes was assessed relative to Thy1.2-labeled retinal ganglion cells (RGCs). RESULTS Pattern electroretinogram amplitudes remained normal in eyes inoculated with scAAV-ND4FLAG, ssAAV-ND4FLAG, and GFP. Confocal microscopy revealed the typical perinuclear mitochondrial expression of scAAV-ND4FLAG in almost the entire retinal flat mount. In contrast, scAAV-GFP expression was cytoplasmic and nuclear. Relative to Thy1.2-positive RGCs, quantification of scAAV-ND4FLAG-positive RGCs was 91% and that of ssAAV-ND4FLAG-positive RGCs was 51%. CONCLUSION Treatment of acute visual loss due to LHON may be possible with a normal human ND4 subunit gene of complex I, mutated in most cases of LHON, when delivered by an scAAV vector. Clinical Relevance Unlike most retinal degenerations that result in slowly progressive loss of vision over many years, LHON due to mutated mitochondrial DNA results in apoplectic, bilateral severe and usually irreversible visual loss. For rescue of acute visual loss in LHON, a highly efficient and rapid gene expression system is required.
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Affiliation(s)
- Rajeshwari D Koilkonda
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 1638 NW 10th Ave., Miami, FL 33136, USA
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Pang J, Boye SE, Lei B, Boye SL, Everhart D, Ryals R, Umino Y, Rohrer B, Alexander J, Li J, Dai X, Li Q, Chang B, Barlow R, Hauswirth WW. Self-complementary AAV-mediated gene therapy restores cone function and prevents cone degeneration in two models of Rpe65 deficiency. Gene Ther 2010; 17:815-26. [PMID: 20237510 DOI: 10.1038/gt.2010.29] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
To test whether fast-acting, self-complimentary (sc), adeno-associated virus-mediated RPE65 expression prevents cone degeneration and/or restores cone function, we studied two mouse lines: the Rpe65-deficient rd12 mouse and the Rpe65-deficient, rhodopsin null ('that is, cone function-only') Rpe65(-/-)::Rho(-/-) mouse. scAAV5 expressing RPE65 was injected subretinally into one eye of rd12 and Rpe65(-/-)::Rho(-/-) mice at postnatal day 14 (P14). Contralateral rd12 eyes were injected later, at P35. Rd12 behavioral testing revealed that rod vision loss was prevented with either P14 or P35 treatment, whereas cone vision was only detected after P14 treatment. Consistent with this observation, P35 treatment only restored rod electroretinogram (ERG) signals, a result likely due to reduced cone densities at this time point. For Rpe65(-/-)::Rho(-/-) mice in which there is no confounding rod contribution to the ERG signal, cone cells and cone-mediated ERGs were also maintained with treatment at P14. This work establishes that a self-complimentary AAV5 vector can restore substantial visual function in two genetically distinct models of Rpe65 deficiency within 4 days of treatment. In addition, this therapy prevents cone degeneration but only if administered before extensive cone degeneration, thus supporting continuation of current Leber's congenital amaurosis-2 clinical trials with an added emphasis on cone subtype analysis and early intervention.
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Affiliation(s)
- J Pang
- Department of Ophthalmology and Powell Gene Therapy Center, University of Florida, Gainesville, FL 32610, USA.
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31
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Kong F, Li W, Li X, Zheng Q, Dai X, Zhou X, Boye SL, Hauswirth WW, Qu J, Pang JJ. Self-complementary AAV5 vector facilitates quicker transgene expression in photoreceptor and retinal pigment epithelial cells of normal mouse. Exp Eye Res 2010; 90:546-54. [PMID: 20138034 DOI: 10.1016/j.exer.2010.01.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 01/25/2010] [Accepted: 01/25/2010] [Indexed: 12/27/2022]
Abstract
To clarify whether transduction efficiency and cell type specificity of self-complementary (sc) AAV5 vectors are similar to those of standard, single-stranded AAV5 vectors in normal retina, one micro liter of scAAV5-smCBA-GFP vector (1 x 10(12) genome-containing particles/ml) and AAV5-smCBA-GFP vector (1 x 10(12) genome-containing particles/ml) were subretinally or intravitreally (in both cases through the cornea) injected into the right and left eyes of adult C57BL/6J mice, respectively. On post-injection day (PID) 1, 2, 5, 7, 10, 14, 21, 28 and 35, eyes were enucleated; retinal pigment epithelium (RPE) wholemounts, neuroretinal wholemounts and eyecup sections were prepared to evaluate green fluorescent protein (GFP) expression by fluorescent microscopy. GFP expression following trans-cornea subretinal injection of scAAV5-smCBA-GFP vector was first detected in RPE wholemounts around PID 1 and in neuroretinal wholemounts between PID 2 and 5; GFP expression peaked and stabilized between PID 10-14 in RPE wholemounts and between P14 and P21 in neuroretinal wholemounts with strong, homogeneous green fluorescence covering the entire wholemounts. The frozen sections supported the following findings from the wholemounts: GFP expression appeared first in RPE around PID 1-2 and soon spread to photoreceptors (PR) cells; by PID 7, moderate GFP expression was found mainly in PR and RPE layers; between PID 14 and 21, strong and homogenous GFP expression was observed in RPE and PR cells. GFP expression following subretinal injection of AAV5-smCBA-GFP was first detected in RPE wholemounts around PID 5-7 and in neuroretinal wholemounts around PID 7-10; ssAAV5-mediated GFP expression peaked at PID 21 in RPE wholemounts and around PID 28 in neuroretinal wholemounts; sections from AAV5 treated eyes also supported findings obtained from wholemounts: GFP expression was first detected in RPE and then spread to the PR cells. Peak GFP expression in RPE mediated by scAAV5 was similar to that mediated by AAV5. However, peak GFP expression mediated by scAAV5 in PR cells was stronger than that mediated by AAV5. No GFP fluorescence was detected in any retinal cells (RPE wholemounts, neuroretinal wholemounts and retinal sections) after trans-cornea intravitreal delivery of either scAAV5-GFP or AAV5-GFP. Neither scAAV5 nor AAV5 can transduce retinal cells following trans-cornea intravitreal injection. The scAAV5 vector used in this study directs an earlier onset of transgene expression than the matched AAV5 vector, and has stronger transgene expression in PR cells following subretinal injection. Our data confirm the previous reports that scAAV vectors have an earlier onset than the standard, single strand AAV vectors (Natkunarajah et al., 2008; Yokoi et al., 2007). scAAV5 vectors may be more useful than standard, single-stranded AAV vector when addressing certain RPE and/or PR cell-related models of retinal dystrophy, particularly for mouse models of human retinitis pigmentosa that require rapid and robust transgene expression to prevent early degeneration in PR cells.
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Affiliation(s)
- Fansheng Kong
- Eye Hospital, School of Ophthalmology & Optometry, Wenzhou Medical College, Wenzhou 325027, China
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32
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Zhang T, Hu J, Ding W, Wang X. Doxorubicin augments rAAV-2 transduction in rat neuronal cells. Neurochem Int 2009; 55:521-8. [PMID: 19450628 DOI: 10.1016/j.neuint.2009.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 05/06/2009] [Accepted: 05/07/2009] [Indexed: 12/29/2022]
Abstract
Doxorubicin, an approved drug for cancer therapy, was recently found to be a potent agent to augment adeno-associated virus (AAV)-mediated transgene expression, especially in airway cells. Recombinant AAV type 2 (rAAV-2) has been shown to preferentially transduce neural tissues and is considered as the primary viral vector for the treatments of various neurodegenerative diseases including Parkinson's disease (PD). The goal of this study is to investigate whether doxorubicin can be applied to increase the efficacy of rAAV-2 transduction in the central nervous system. We co-administrated doxorubicin with AV2.luc/EGFP into the rat striatum, a preferred target site for PD gene therapy, and found that doxorubicin augmented rAAV-2 transduction dramatically without significant cytotoxicity and alteration of rAAV-2 tropism. By evaluating the effects of doxorubicin on rAAV-2 transduction in PC12 and MN9D neuronal cells, we found that doxorubicin appeared to promote the nuclear accumulation of rAAV-2, but did not affect viral binding or uptake. Our data suggested that doxorubicin might play an important role in modulating rAAV-2 intracellular trafficking in neuron-like cells. Our study also provided the initial in vivo evidence to facilitate AAV-mediated gene expression in the midbrain with the treatment of doxorubicin.
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Affiliation(s)
- Ting Zhang
- Neuroscience Research Institute, Peking University, China
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33
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High-efficiency transduction of the mouse retina by tyrosine-mutant AAV serotype vectors. Mol Ther 2008; 17:463-71. [PMID: 19066593 DOI: 10.1038/mt.2008.269] [Citation(s) in RCA: 312] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Vectors derived from adeno-associated viruses (AAVs) have become important gene delivery tools for the treatment of many inherited ocular diseases in well-characterized animal models. Previous studies have determined that the viral capsid plays an essential role in the cellular tropism and efficiency of transgene expression. Recently, it was shown that phosphorylation of surface-exposed tyrosine residues from AAV2 capsid targets the viral particles for ubiquitination and proteasome- mediated degradation, and mutations of these tyrosine residues lead to highly efficient vector transduction in vitro and in vivo. Because the tyrosine residues are highly conserved in other AAV serotypes, in this study we evaluated the intraocular transduction characteristics of vectors containing point mutations in surface- exposed capsid tyrosine residues in AAV serotypes 2, 8, and 9. Several of these novel AAV mutants were found to display a strong and widespread transgene expression in many retinal cells after subretinal or intravitreal delivery compared with their wild-type counterparts. For the first time, we show efficient transduction of the ganglion cell layer by AAV serotype 8 or 9 mutant vectors, thus providing additional tools besides AAV2 for targeting these cells. These enhanced AAV vectors have a great potential for future therapeutic applications for retinal degenerations and ocular neovascular diseases.
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35
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Buch PK, Bainbridge JW, Ali RR. AAV-mediated gene therapy for retinal disorders: from mouse to man. Gene Ther 2008; 15:849-57. [PMID: 18418417 DOI: 10.1038/gt.2008.66] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A wide range of retinal disorders can potentially be treated using viral vector-mediated gene therapy. The most widely used vectors for ocular gene delivery are based on adeno-associated virus (AAV), because they elicit minimal immune responses and mediate long-term transgene expression in a variety of retinal cell types. Proof-of-concept experiments have demonstrated the efficacy of AAV-mediated transgene delivery in a number of animal models of inherited and acquired retinal disorders. Following extensive preclinical evaluation in large animal models, gene therapy for one form of inherited retinal degeneration due to RPE65 deficiency is now being tested in three concurrent clinical trials. Here, we review different approaches for treating inherited retinal degenerations and more common acquired retinal disorders using AAV-based vectors.
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Affiliation(s)
- P K Buch
- Division of Molecular Therapy, UCL Institute of Ophthalmology and UCL/Moorfields Eye Hospital Biomedical Research Centre for Ophthalmology, London, UK
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Paskowitz DM, Greenberg KP, Yasumura D, Grimm D, Yang H, Duncan JL, Kay MA, Lavail MM, Flannery JG, Vollrath D. Rapid and Stable Knockdown of an Endogenous Gene in Retinal Pigment Epithelium. Hum Gene Ther 2007; 18:871-80. [PMID: 17892416 DOI: 10.1089/hum.2007.065] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The selective silencing of target genes in specific cell types by RNA interference (RNAi) represents a powerful approach both to gene therapy of dominantly active mutant alleles, and to the investigation of normal gene function in animal models in vivo. We established a simple and versatile in vitro method for screening the efficacy of DNA-based short hairpin RNAs (shRNAs), and identified a highly effective shRNA targeting basic fibroblast growth factor (bFGF), a gene thought to play important roles in endogenous neuroprotective responses in the rat retina. We used two viral vectors, based on lentivirus and adeno-associated virus (AAV), to deliver shRNAs and silence bFGF in retinal pigment epithelial cells in vivo. The AAV experiments made use of a "stabilized double-stranded" version of these vectors with rapid onset of gene expression. In the rat retinal pigment epithelium, shRNAs delivered by either vector reduced bFGF immunoreactivity to undetectable levels in transduced cells, whereas a nonfunctional control construct incorporating a two-base pair mutation had no measurable effect on bFGF expression. Silencing commenced within a few days after injection of virus and remained stable throughout the period of observation, as long as 60 days. Viral delivery of RNAi constructs offers a powerful and versatile approach for both gene therapy and the analysis of fundamental questions in retinal biology.
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Affiliation(s)
- Daniel M Paskowitz
- Beckman Vision Center, University of California, San Francisco, San Francisco, CA 94143, USA
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