1
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Appell MB, Pejavar J, Pasupathy A, Rompicharla SVK, Abbasi S, Malmberg K, Kolodziejski P, Ensign LM. Next generation therapeutics for retinal neurodegenerative diseases. J Control Release 2024; 367:708-736. [PMID: 38295996 PMCID: PMC10960710 DOI: 10.1016/j.jconrel.2024.01.063] [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: 08/14/2023] [Revised: 01/05/2024] [Accepted: 01/28/2024] [Indexed: 02/13/2024]
Abstract
Neurodegenerative diseases affecting the visual system encompass glaucoma, macular degeneration, retinopathies, and inherited genetic disorders such as retinitis pigmentosa. These ocular pathologies pose a serious burden of visual impairment and blindness worldwide. Current treatment modalities include small molecule drugs, biologics, or gene therapies, most of which are administered topically as eye drops or as injectables. However, the topical route of administration faces challenges in effectively reaching the posterior segment and achieving desired concentrations at the target site, while injections and implants risk severe complications, such as retinal detachment and endophthalmitis. This necessitates the development of innovative therapeutic strategies that can prolong drug release, deliver effective concentrations to the back of the eye with minimal systemic exposure, and improve patient compliance and safety. In this review, we introduce retinal degenerative diseases, followed by a discussion of the existing clinical standard of care. We then delve into detail about drug and gene delivery systems currently in preclinical and clinical development, including formulation and delivery advantages/drawbacks, with a special emphasis on potential for clinical translation.
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Affiliation(s)
- Matthew B Appell
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Jahnavi Pejavar
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Ashwin Pasupathy
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Sri Vishnu Kiran Rompicharla
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Saed Abbasi
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Kiersten Malmberg
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Patricia Kolodziejski
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA
| | - Laura M Ensign
- Center for Nanomedicine at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Departments of Gynecology and Obstetrics, Biomedical Engineering, Oncology, and Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
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2
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Whalen M, Akula M, McNamee SM, DeAngelis MM, Haider NB. Seeing the Future: A Review of Ocular Therapy. Bioengineering (Basel) 2024; 11:179. [PMID: 38391665 PMCID: PMC10886198 DOI: 10.3390/bioengineering11020179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/03/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
Ocular diseases present a unique challenge and opportunity for therapeutic development. The eye has distinct advantages as a therapy target given its accessibility, compartmentalization, immune privilege, and size. Various methodologies for therapeutic delivery in ocular diseases are under investigation that impact long-term efficacy, toxicity, invasiveness, and delivery range. While gene, cell, and antibody therapy and nanoparticle delivery directly treat regions that have been damaged by disease, they can be limited in the duration of the therapeutic delivery and have a focal effect. In contrast, contact lenses and ocular implants can more effectively achieve sustained and widespread delivery of therapies; however, they can increase dilution of therapeutics, which may result in reduced effectiveness. Current therapies either offer a sustained release or a broad therapeutic effect, and future directions should aim toward achieving both. This review discusses current ocular therapy delivery systems and their applications, mechanisms for delivering therapeutic products to ocular tissues, advantages and challenges associated with each delivery system, current approved therapies, and clinical trials. Future directions for the improvement in existing ocular therapies include combination therapies, such as combined cell and gene therapies, as well as AI-driven devices, such as cortical implants that directly transmit visual information to the cortex.
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Affiliation(s)
- Maiya Whalen
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | | | - Margaret M DeAngelis
- Department of Ophthalmology, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Neena B Haider
- Shifa Precision, Boston, MA 02138, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02138, USA
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3
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Matsevich C, Gopalakrishnan P, Chang N, Obolensky A, Beryozkin A, Salameh M, Kostic C, Sharon D, Arsenijevic Y, Banin E. Gene augmentation therapy attenuates retinal degeneration in a knockout mouse model of Fam161a retinitis pigmentosa. Mol Ther 2023; 31:2948-2961. [PMID: 37580905 PMCID: PMC10556223 DOI: 10.1016/j.ymthe.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 07/14/2023] [Accepted: 08/10/2023] [Indexed: 08/16/2023] Open
Abstract
Photoreceptor cell degeneration and death is the major hallmark of a wide group of human blinding diseases including age-related macular degeneration and inherited retinal diseases such as retinitis pigmentosa. In recent years, inherited retinal diseases have become the "testing ground" for novel therapeutic modalities, including gene and cell-based therapies. Currently there is no available treatment for retinitis pigmentosa caused by FAM161A biallelic pathogenic variants. In this study, we injected an adeno-associated virus encoding for the longer transcript of mFam161a into the subretinal space of P24-P29 Fam161a knockout mice to characterize the safety and efficacy of gene augmentation therapy. Serial in vivo assessment of retinal function and structure at 3, 6, and 8 months of age using the optomotor response test, full-field electroretinography, fundus autofluorescence, and optical coherence tomography imaging as well as ex vivo quantitative histology and immunohistochemical studies revealed a significant structural and functional rescue effect in treated eyes accompanied by expression of the FAM161A protein in photoreceptors. The results of this study may serve as an important step toward future application of gene augmentation therapy in FAM161A-deficient patients by identifying a promising isoform to rescue photoreceptors and their function.
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Affiliation(s)
- Chen Matsevich
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | | | - Ning Chang
- Group for Retinal Disorder Research, Department of Ophthalmology, University Lausanne - Jules-Gonin Eye Hospital Fondation Asile des Aveugles, Lausanne, Switzerland
| | - Alexey Obolensky
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Avigail Beryozkin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Manar Salameh
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Corinne Kostic
- Group for Retinal Disorder Research, Department of Ophthalmology, University Lausanne - Jules-Gonin Eye Hospital Fondation Asile des Aveugles, Lausanne, Switzerland
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
| | - Yvan Arsenijevic
- Unit of Retinal Degeneration and Regeneration, Department of Ophthalmology, University Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland
| | - Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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4
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Pan H, Liu YF, Luo Y, Chen L, Shen B, Song S, Liu M, Wang Z, Wu W, Li M, Zhang Y. Goats with low levels of AAV antibody may serve as candidates for large animal gene therapy. Exp Eye Res 2023; 233:109514. [PMID: 37207869 DOI: 10.1016/j.exer.2023.109514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/11/2023] [Accepted: 05/16/2023] [Indexed: 05/21/2023]
Abstract
AAV vector-mediated gene therapy has been proposed as a feasible strategy for several eye diseases. However, AAV antibodies in the serum prior to treatment hinder the transduction efficiency and thus the therapeutic effect. Therefore, it is necessary to evaluate AAV antibodies in the serum before gene therapy. As large animals, goats are more closely related to humans than rodents and more economically available than nonhuman primates. Here, we first evaluated the AAV2 antibody serum level in rhesus monkeys before AAV injection. Then, we optimized a cell-based neutralizing antibody assay for detecting AAV antibodies in the serum of Saanen goats and evaluated the consistency of the cell-based neutralizing antibody assay and ELISA for goat serum antibody evaluation. The cell-based neutralizing antibody assay showed that the percentage of macaques with low antibody levels was 42.86%; however, there were no macaques with low antibody levels when the serum was evaluated by ELISA. The proportion of goats with low antibody levels was 56.67% according to the neutralizing antibody assay and 33. 33% according to the ELISA, and McNemar's test showed that the results of the two assays were not significantly different (P = 0.754), but that their consistency is poor (Kappa = 0.286, P = 0.114). Moreover, longitudinal evaluation of serum antibodies before and after intravitreal injection of AAV2 in goats revealed that the level of AAV antibodies increased and transduction inhibition subsequently increased, as reported in humans, indicating that transduction inhibition should be taken into account at different stages of gene therapy. In summary, starting with an evaluation of monkey serum antibodies, we optimized a detection method of goat serum antibodies, providing an alternative large animal model for gene therapy, and our serum antibody measurement method may be applied to other large animals.
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Affiliation(s)
- Huirong Pan
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Yu-Fen Liu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Yuting Luo
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Lili Chen
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Bingyan Shen
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Shihan Song
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Mingyue Liu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Zhuowei Wang
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Wencan Wu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - Mengyun Li
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; Shaoxing People's Hospital, Shaoxing, 312000, China.
| | - Yikui Zhang
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
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5
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Hammadi S, Tzoumas N, Ferrara M, Meschede IP, Lo K, Harris C, Lako M, Steel DH. Bruch's Membrane: A Key Consideration with Complement-Based Therapies for Age-Related Macular Degeneration. J Clin Med 2023; 12:2870. [PMID: 37109207 PMCID: PMC10145879 DOI: 10.3390/jcm12082870] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
The complement system is crucial for immune surveillance, providing the body's first line of defence against pathogens. However, an imbalance in its regulators can lead to inappropriate overactivation, resulting in diseases such as age-related macular degeneration (AMD), a leading cause of irreversible blindness globally affecting around 200 million people. Complement activation in AMD is believed to begin in the choriocapillaris, but it also plays a critical role in the subretinal and retinal pigment epithelium (RPE) spaces. Bruch's membrane (BrM) acts as a barrier between the retina/RPE and choroid, hindering complement protein diffusion. This impediment increases with age and AMD, leading to compartmentalisation of complement activation. In this review, we comprehensively examine the structure and function of BrM, including its age-related changes visible through in vivo imaging, and the consequences of complement dysfunction on AMD pathogenesis. We also explore the potential and limitations of various delivery routes (systemic, intravitreal, subretinal, and suprachoroidal) for safe and effective delivery of conventional and gene therapy-based complement inhibitors to treat AMD. Further research is needed to understand the diffusion of complement proteins across BrM and optimise therapeutic delivery to the retina.
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Affiliation(s)
- Sarah Hammadi
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Nikolaos Tzoumas
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
| | | | - Ingrid Porpino Meschede
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Katharina Lo
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
| | - Claire Harris
- Gyroscope Therapeutics Limited, a Novartis Company, Rolling Stock Yard, 6th Floor, 188 York Way, London N7 9AS, UK
- Clinical and Translational Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Majlinda Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - David H. Steel
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Sunderland Eye Infirmary, Queen Alexandra Rd., Sunderland SR2 9H, UK
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6
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Ross M, Obolensky A, Averbukh E, Desrosiers M, Ezra-Elia R, Honig H, Yamin E, Rosov A, Dvir H, Gootwine E, Banin E, Dalkara D, Ofri R. Outer retinal transduction by AAV2-7m8 following intravitreal injection in a sheep model of CNGA3 achromatopsia. Gene Ther 2022; 29:624-635. [PMID: 34853444 DOI: 10.1038/s41434-021-00306-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2021] [Revised: 10/26/2021] [Accepted: 11/15/2021] [Indexed: 01/09/2023]
Abstract
Sheep carrying a mutated CNGA3 gene exhibit diminished cone function and provide a naturally occurring large animal model of achromatopsia. Subretinal injection of a vector carrying the CNGA3 transgene resulted in long-term recovery of cone function and photopic vision in these sheep. Research is underway to develop efficacious vectors that would enable safer transgene delivery, while avoiding potential drawbacks of subretinal injections. The current study evaluated two modified vectors, adeno-associated virus 2-7m8 (AAV2-7m8) and AAV9-7m8. Intravitreal injection of AAV2-7m8 carrying enhanced green fluorescent protein under a cone-specific promoter resulted in moderate photoreceptor transduction in wild-type sheep, whereas peripheral subretinal delivery of AAV9-7m8 resulted in the radial spread of the vector beyond the point of deposition. Intravitreal injection of AAV2-7m8 carrying human CNGA3 in mutant sheep resulted in mild photoreceptor transduction, but did not lead to the clinical rescue of photopic vision, while day-blind sheep treated with a subretinal injection exhibited functional recovery of photopic vision. Transgene messenger RNA levels in retinas of intravitreally treated eyes amounted to 4-23% of the endogenous CNGA3 levels, indicating that expression levels >23% are needed to achieve clinical rescue. Overall, our results indicate intravitreal injections of AAV2.7m8 transduce ovine photoreceptors, but not with sufficient efficacy to achieve clinical rescue in CNGA3 mutant sheep.
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Affiliation(s)
- M Ross
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - A Obolensky
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - E Averbukh
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - M Desrosiers
- Department of Therapeutics, Institut de la Vision, Paris, France
| | - R Ezra-Elia
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - H Honig
- Department of Animal Science, ARO, The Volcani Center, Rishon LeZion, Israel
| | - E Yamin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - A Rosov
- Department of Animal Science, ARO, The Volcani Center, Rishon LeZion, Israel
| | - H Dvir
- Department of Animal Science, ARO, The Volcani Center, Rishon LeZion, Israel
| | - E Gootwine
- Department of Animal Science, ARO, The Volcani Center, Rishon LeZion, Israel
| | - E Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - D Dalkara
- Department of Therapeutics, Institut de la Vision, Paris, France
| | - R Ofri
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel.
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Murray SJ, Mitchell NL. Natural history of retinal degeneration in ovine models of CLN5 and CLN6 neuronal ceroid lipofuscinoses. Sci Rep 2022; 12:3670. [PMID: 35256654 PMCID: PMC8901734 DOI: 10.1038/s41598-022-07612-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/14/2022] [Indexed: 11/08/2022] Open
Abstract
Neuronal ceroid lipofuscinoses (NCL; Batten disease) are a group of inherited neurodegenerative diseases with a common set of symptoms including cognitive and motor decline and vision loss. Naturally occurring sheep models of CLN5 and CLN6 disease display the key clinical features of NCL, including a progressive loss of vision. We assessed retinal histology, astrogliosis, and lysosomal storage accumulation in CLN5 affected (CLN5-/-) and CLN6 affected (CLN6-/-) sheep eyes and age-matched controls at 3, 6, 12, and 18 months of age to determine the onset and progression of retinal pathology in NCL sheep. The retina of CLN5-/- sheep shows progressive atrophy of the outer retinal layers, widespread gliosis, and accumulation of lysosomal storage in retinal ganglion cells late in disease. In contrast, CLN6-/- retina shows significant atrophy of all retinal layers, progressive gliosis, and earlier accumulation of lysosomal storage. This study has highlighted the differential vulnerability of retinal layers and the time course of retinal atrophy in two distinct models of NCL disease. This data will be valuable in determining potential targets for ocular therapies and the optimal timing of these therapies for protection from retinal dysfunction and degeneration in NCL.
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Affiliation(s)
- S J Murray
- Faculty of Agriculture and Life Sciences, Lincoln University, PO Box 85084, Lincoln, Canterbury, 7647, New Zealand
| | - N L Mitchell
- Faculty of Agriculture and Life Sciences, Lincoln University, PO Box 85084, Lincoln, Canterbury, 7647, New Zealand.
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8
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Ross M, Ofri R. The future of retinal gene therapy: evolving from subretinal to intravitreal vector delivery. Neural Regen Res 2021; 16:1751-1759. [PMID: 33510064 PMCID: PMC8328774 DOI: 10.4103/1673-5374.306063] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/26/2020] [Accepted: 12/09/2020] [Indexed: 12/18/2022] Open
Abstract
Inherited retinal degenerations are a leading and untreatbale cause of blindness, and as such they are targets for gene therapy. Numerous gene therapy treatments have progressed from laboratory research to clinical trails, and a pioneering gene therapy received the first ever FDA approval for treating patients. However, currently retinal gene therapy mostly involves subretinal injection of the therapeutic agent, which treats a limited area, entails retinal detachment and other potential complications, and requires general anesthesia with consequent risks, costs and prolonged recovery. Therefore there is great impetus to develop safer, less invasive and cheapter methods of gene delivery. A promising method is intravitreal injection, that does not cause retinal detachment, can lead to pan-retinal transduction and can be performed under local anesthesia in out-patient clinics. Intravitreally-injected vectors face several obstacles. First, the vector is diluted by the vitreous and has to overcome a long diffusion distance to the target cells. Second, the vector is exposed to the host's immune response, risking neutralization by pre-existing antibodies and triggering a stronger immune response to the injection. Third, the vector has to cross the inner limiting membrane which is both a physical and a biological barrier as it contains binding sites that could cause the vector's sequestration. Finally, in the target cell the vector is prone to proteasome degradation before delivering the transgene to the nucleus. Strategies to overcome these obstacles include modifications of the viral capsid, through rational design or directed evolution, which allow resistance to the immune system, enhancement of penetration through the inner limiting membrane or reduced degradation by intracellular proteasomes. Furthermore, physical and chemical manipulations of the inner limiting membrane and vitreous aim to improve vector penetration. Finally, compact non-viral vectors that can overcome the immunological, physical and anatomical and barriers have been developed. This paper reviews ongoing efforts to develop novel, safe and efficacious methods for intravitreal delivery of therapeutic genes for inherited retinal degenerations. To date, the most promising results are achieved in rodents with robust, pan-retinal transduction following intravitreal delivery. Trials in larger animal models demonstrate transduction mostly of inner retinal layers. Despite ongoing efforts, currently no intravitreally-injected vector has demonstrated outer retinal transduction efficacy comparable to that of subretinal delivery. Further work is warranted to test promising new viral and non-viral vectors on large animal models of inherited retinal degenerations. Positive results will pave the way to development of the next generation of treatments for inherited retinal degeneration.
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Affiliation(s)
- Maya Ross
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ron Ofri
- Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot, Israel
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9
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Sahu B, Chug I, Khanna H. The Ocular Gene Delivery Landscape. Biomolecules 2021; 11:1135. [PMID: 34439800 PMCID: PMC8394578 DOI: 10.3390/biom11081135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 07/19/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
The eye is at the forefront of developing therapies for genetic diseases. With the FDA approval of the first gene-therapy drug for a form of congenital blindness, numerous studies have been initiated to develop gene therapies for other forms of eye diseases. These examinations have revealed new information about the benefits as well as restrictions to using drug-delivery routes to the different parts of the eye. In this article, we will discuss a brief history of gene therapy and its importance to the eye and ocular delivery landscape that is currently being investigated, and provide insights into their advantages and disadvantages. Efficient delivery routes and vehicle are crucial for an effective, safe, and longer-lasting therapy.
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Affiliation(s)
| | | | - Hemant Khanna
- Department of Ophthalmology & Visual Sciences, UMass Medical School, Worcester, MA 01655, USA; (B.S.); (I.C.)
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10
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Murray SJ, Russell KN, Melzer TR, Gray SJ, Heap SJ, Palmer DN, Mitchell NL. Intravitreal gene therapy protects against retinal dysfunction and degeneration in sheep with CLN5 Batten disease. Exp Eye Res 2021; 207:108600. [PMID: 33930398 DOI: 10.1016/j.exer.2021.108600] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 04/12/2021] [Accepted: 04/21/2021] [Indexed: 01/01/2023]
Abstract
Neuronal ceroid lipofuscinoses (NCL; Batten disease) are a group of inherited neurodegenerative diseases primarily affecting children. A common feature across most NCLs is the progressive loss of vision. We performed intravitreal injections of self-complementary AAV9 vectors packaged with either ovine CLN5 or CLN6 into one eye of 3-month-old CLN5-/- or CLN6-/- animals, respectively. Electroretinography (ERG) was performed every month following treatment, and retinal histology was assessed post-mortem in the treated compared to untreated eye. In CLN5-/- animals, ERG amplitudes were normalised in the treated eye whilst the untreated eye declined in a similar manner to CLN5 affected controls. In CLN6-/- animals, ERG amplitudes in both eyes declined over time although the treated eye showed a slower decline. Post-mortem examination revealed significant attenuation of retinal atrophy and lysosomal storage body accumulation in the treated eye compared with the untreated eye in CLN5-/- animals. This proof-of-concept study provides the first observation of efficacious intravitreal gene therapy in a large animal model of NCL. In particular, the single administration of AAV9-mediated intravitreal gene therapy can successfully ameliorate retinal deficits in CLN5-/- sheep. Combining ocular gene therapy with brain-directed therapy presents a promising treatment strategy to be used in future sheep trials aiming to halt neurological and retinal disease in CLN5 Batten disease.
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Affiliation(s)
- Samantha J Murray
- Faculty of Agricultural and Life Sciences, Lincoln University, Lincoln, 7647, New Zealand
| | - Katharina N Russell
- Faculty of Agricultural and Life Sciences, Lincoln University, Lincoln, 7647, New Zealand
| | - Tracy R Melzer
- Department of Medicine, University of Otago, Christchurch and the New Zealand Brain Research Institute, Christchurch, 8011, New Zealand
| | - Steven J Gray
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Stephen J Heap
- McMaster & Heap Veterinary Practice, Christchurch, 8025, New Zealand
| | - David N Palmer
- Faculty of Agricultural and Life Sciences, Lincoln University, Lincoln, 7647, New Zealand; Department of Radiology, University of Otago, Christchurch, 8140, New Zealand
| | - Nadia L Mitchell
- Faculty of Agricultural and Life Sciences, Lincoln University, Lincoln, 7647, New Zealand; Department of Radiology, University of Otago, Christchurch, 8140, New Zealand.
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Crane R, Conley SM, Al-Ubaidi MR, Naash MI. Gene Therapy to the Retina and the Cochlea. Front Neurosci 2021; 15:652215. [PMID: 33815052 PMCID: PMC8010260 DOI: 10.3389/fnins.2021.652215] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/22/2021] [Indexed: 12/20/2022] Open
Abstract
Vision and hearing disorders comprise the most common sensory disorders found in people. Many forms of vision and hearing loss are inherited and current treatments only provide patients with temporary or partial relief. As a result, developing genetic therapies for any of the several hundred known causative genes underlying inherited retinal and cochlear disorders has been of great interest. Recent exciting advances in gene therapy have shown promise for the clinical treatment of inherited retinal diseases, and while clinical gene therapies for cochlear disease are not yet available, research in the last several years has resulted in significant advancement in preclinical development for gene delivery to the cochlea. Furthermore, the development of somatic targeted genome editing using CRISPR/Cas9 has brought new possibilities for the treatment of dominant or gain-of-function disease. Here we discuss the current state of gene therapy for inherited diseases of the retina and cochlea with an eye toward areas that still need additional development.
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Affiliation(s)
- Ryan Crane
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- College of Optometry, University of Houston, Houston, TX, United States
- Depatment of Biology and Biochemistry, University of Houston, Houston, TX, United States
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- College of Optometry, University of Houston, Houston, TX, United States
- Depatment of Biology and Biochemistry, University of Houston, Houston, TX, United States
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Ali RR. Retinal Gene Therapy: Expansion in Clinical Trials Drives the Need for Further Preclinical Research. Hum Gene Ther 2020; 31:701-702. [PMID: 32716735 DOI: 10.1089/hum.2020.29129.rra] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Robin R Ali
- Centre for Cell and Gene Therapy, King's College London, London, United Kingdom.,Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, USA
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