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Ashok S, Ramachandra Rao S. Updates on protein-prenylation and associated inherited retinopathies. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1410874. [PMID: 39026984 PMCID: PMC11254824 DOI: 10.3389/fopht.2024.1410874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 06/13/2024] [Indexed: 07/20/2024]
Abstract
Membrane-anchored proteins play critical roles in cell signaling, cellular architecture, and membrane biology. Hydrophilic proteins are post-translationally modified by a diverse range of lipid molecules such as phospholipids, glycosylphosphatidylinositol, and isoprenes, which allows their partition and anchorage to the cell membrane. In this review article, we discuss the biochemical basis of isoprenoid synthesis, the mechanisms of isoprene conjugation to proteins, and the functions of prenylated proteins in the neural retina. Recent discovery of novel prenyltransferases, prenylated protein chaperones, non-canonical prenylation-target motifs, and reversible prenylation is expected to increase the number of inherited systemic and blinding diseases with aberrant protein prenylation. Recent important investigations have also demonstrated the role of several unexpected regulators (such as protein charge, sequence/protein-chaperone interaction, light exposure history) in the photoreceptor trafficking of prenylated proteins. Technical advances in the investigation of the prenylated proteome and its application in vision research are discussed. Clinical updates and technical insights into known and putative prenylation-associated retinopathies are provided herein. Characterization of non-canonical prenylation mechanisms in the retina and retina-specific prenylated proteome is fundamental to the understanding of the pathogenesis of protein prenylation-associated inherited blinding disorders.
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Affiliation(s)
- Sudhat Ashok
- Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY, United States
| | - Sriganesh Ramachandra Rao
- Department of Ophthalmology, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY, United States
- Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY, United States
- Research Service, VA Western New York Healthcare System, Buffalo, NY, United States
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2
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Raeker MÖ, Perera ND, Karoukis AJ, Chen L, Feathers KL, Ali RR, Thompson DA, Fahim AT. Reduced Retinal Pigment Epithelial Autophagy Due to Loss of Rab12 Prenylation in a Human iPSC-RPE Model of Choroideremia. Cells 2024; 13:1068. [PMID: 38920696 PMCID: PMC11201631 DOI: 10.3390/cells13121068] [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: 04/23/2024] [Revised: 05/31/2024] [Accepted: 06/14/2024] [Indexed: 06/27/2024] Open
Abstract
Choroideremia is an X-linked chorioretinal dystrophy caused by mutations in CHM, encoding Rab escort protein 1 (REP-1), leading to under-prenylation of Rab GTPases (Rabs). Despite ubiquitous expression of CHM, the phenotype is limited to degeneration of the retina, retinal pigment epithelium (RPE), and choroid, with evidence for primary pathology in RPE cells. However, the spectrum of under-prenylated Rabs in RPE cells and how they contribute to RPE dysfunction remain unknown. A CRISPR/Cas-9-edited CHM-/- iPSC-RPE model was generated with isogenic control cells. Unprenylated Rabs were biotinylated in vitro and identified by tandem mass tag (TMT) spectrometry. Rab12 was one of the least prenylated and has an established role in suppressing mTORC1 signaling and promoting autophagy. CHM-/- iPSC-RPE cells demonstrated increased mTORC1 signaling and reduced autophagic flux, consistent with Rab12 dysfunction. Autophagic flux was rescued in CHM-/- cells by transduction with gene replacement (ShH10-CMV-CHM) and was reduced in control cells by siRNA knockdown of Rab12. This study supports Rab12 under-prenylation as an important cause of RPE cell dysfunction in choroideremia and highlights increased mTORC1 and reduced autophagy as potential disease pathways for further investigation.
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Affiliation(s)
- Maide Ö. Raeker
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
| | - Nirosha D. Perera
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
| | - Athanasios J. Karoukis
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
| | - Lisheng Chen
- Department of Orthopedic Surgery, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Kecia L. Feathers
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
| | - Robin R. Ali
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
- KCL Center for Cell and Gene Therapy, London WC2R 2LS, UK
| | - Debra A. Thompson
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Abigail T. Fahim
- Department of Ophthalmology, University of Michigan, Ann Arbor, MI 48105, USA; (M.Ö.R.); (N.D.P.); (A.J.K.); (K.L.F.); (R.R.A.); (D.A.T.)
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Erol ÖD, Şenocak Ş, Aerts-Kaya F. The Role of Rab GTPases in the development of genetic and malignant diseases. Mol Cell Biochem 2024; 479:255-281. [PMID: 37060515 DOI: 10.1007/s11010-023-04727-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/01/2023] [Indexed: 04/16/2023]
Abstract
Small GTPases have been shown to play an important role in several cellular functions, including cytoskeletal remodeling, cell polarity, intracellular trafficking, cell-cycle, progression and lipid transformation. The Ras-associated binding (Rab) family of GTPases constitutes the largest family of GTPases and consists of almost 70 known members of small GTPases in humans, which are known to play an important role in the regulation of intracellular membrane trafficking, membrane identity, vesicle budding, uncoating, motility and fusion of membranes. Mutations in Rab genes can cause a wide range of inherited genetic diseases, ranging from neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD) to immune dysregulation/deficiency syndromes, like Griscelli Syndrome Type II (GS-II) and hemophagocytic lymphohistiocytosis (HLH), as well as a variety of cancers. Here, we provide an extended overview of human Rabs, discussing their function and diseases related to Rabs and Rab effectors, as well as focusing on effects of (aberrant) Rab expression. We aim to underline their importance in health and the development of genetic and malignant diseases by assessing their role in cellular structure, regulation, function and biology and discuss the possible use of stem cell gene therapy, as well as targeting of Rabs in order to treat malignancies, but also to monitor recurrence of cancer and metastasis through the use of Rabs as biomarkers. Future research should shed further light on the roles of Rabs in the development of multifactorial diseases, such as diabetes and assess Rabs as a possible treatment target.
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Affiliation(s)
- Özgür Doğuş Erol
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Şimal Şenocak
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Fatima Aerts-Kaya
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey.
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey.
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MacLaren RE, Fischer MD, Gow JA, Lam BL, Sankila EMK, Girach A, Panda S, Yoon D, Zhao G, Pennesi ME. Subretinal timrepigene emparvovec in adult men with choroideremia: a randomized phase 3 trial. Nat Med 2023; 29:2464-2472. [PMID: 37814062 PMCID: PMC10579095 DOI: 10.1038/s41591-023-02520-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 07/28/2023] [Indexed: 10/11/2023]
Abstract
Choroideremia is a rare, X-linked retinal degeneration resulting in progressive vision loss. A randomized, masked, phase 3 clinical trial evaluated the safety and efficacy over 12 months of follow-up in adult males with choroideremia randomized to receive a high-dose (1.0 × 1011 vector genomes (vg); n = 69) or low-dose (1.0 × 1010 vg; n = 34) subretinal injection of the AAV2-vector-based gene therapy timrepigene emparvovec versus non-treated control (n = 66). Most treatment-emergent adverse events were mild or moderate. The trial did not meet its primary endpoint of best-corrected visual acuity (BCVA) improvement. In the primary endpoint analysis, three of 65 participants (5%) in the high-dose group, one of 34 (3%) participants in the low-dose group and zero of 62 (0%) participants in the control group had ≥15-letter Early Treatment Diabetic Retinopathy Study (ETDRS) improvement from baseline BCVA at 12 months (high dose, P = 0.245 versus control; low dose, P = 0.354 versus control). As the primary endpoint was not met, key secondary endpoints were not tested for significance. In a key secondary endpoint, nine of 65 (14%), six of 35 (18%) and one of 62 (2%) participants in the high-dose, low-dose and control groups, respectively, experienced ≥10-letter ETDRS improvement from baseline BCVA at 12 months. Potential opportunities to enhance future gene therapy studies for choroideremia include optimization of entry criteria (more preserved retinal area), surgical techniques and clinical endpoints. EudraCT registration: 2015-003958-41 .
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Affiliation(s)
- Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
- Oxford University Hospitals NIHR Biomedical Research Centre, Oxford, UK.
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
| | - M Dominik Fischer
- University Eye Hospital Tübingen, Center for Ophthalmology, Tübingen, Germany
| | | | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | - Aniz Girach
- Formerly of Nightstar Therapeutics, London, UK
| | | | | | | | - Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
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A patient advocating for transparent science in rare disease research. Orphanet J Rare Dis 2023; 18:14. [PMID: 36658594 PMCID: PMC9854194 DOI: 10.1186/s13023-022-02557-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 06/14/2022] [Accepted: 10/12/2022] [Indexed: 01/20/2023] Open
Abstract
300 million people live with at least one of 6,000 rare diseases worldwide. However, rare disease research is not always reviewed with scrutiny, making it susceptible to what the author refers to as nontransparent science. Nontransparent science can obscure animal model flaws, misguide medicine regulators and drug developers, delay or frustrate orphan drug development, or waste limited resources for rare disease research. Flawed animal models not only lack pharmacologic relevance, but also give rise to issue of clinical translatability. Sadly, these consequences and risks are grossly overlooked. Nontransparency in science can take many forms, such as premature publication of animal models without clinically significant data, not providing corrections when flaws to the model are discovered, lack of warning of critical study limitations, missing critical control data, questionable data quality, surprising results without a sound explanation, failure to rule out potential factors which may affect study conclusions, lack of sufficient detail for others to replicate the study, dubious authorship and study accountability. Science has no boarders, neither does nontransparent science. Nontransparent science can happen irrespective of the researcher's senority, institutional affiliation or country. As a patient-turned researcher suffering from Bietti crystalline dystrophy (BCD), I use BCD as an example to analyze various forms of nontransparent science in rare disease research. This article analyzes three papers published by different research groups on Cyp4v3-/-, high-fat diet (HFD)-Cyp4v3-/-, and Exon1-Cyp4v3-/- mouse models of BCD. As the discussion probes various forms of nontransparent science, the flaws of these knockout mouse models are uncovered. These mouse models do not mimic BCD in humans nor do they address the lack of Cyp4v3 (murine ortholog of human CYP4V2) expression in wild type (WT) mouse retina which is markedly different from CYP4V2 expression in human retina. Further, this article discusses the impact of nontransparent science on drug development which can lead to significant delays ultimately affecting the patients. Lessons from BCD research can be helpful to all those suffering from rare diseases. As a patient, I call for transparent science in rare disease research.
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AAV2-hCHM Subretinal Delivery to the Macula in Choroideremia: Two Year Interim Results of an Ongoing Phase I/II Gene Therapy Trial. Ophthalmology 2022; 129:1177-1191. [PMID: 35714735 DOI: 10.1016/j.ophtha.2022.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 11/22/2022] Open
Abstract
PURPOSE To assess the safety of the subretinal delivery of a recombinant adeno-associated virus serotype 2 (AAV2) vector carrying a human CHM-encoding cDNA in choroideremia (CHM). DESIGN Prospective, open-label, non-randomized, dose-escalation, phase 1/2 clinical trial. SUBJECTS, PARTICIPANTS, AND/OR CONTROLS Fifteen CHM patients (ages 20-57 years at dosing). METHODS, INTERVENTION, OR TESTING Patients received uniocular subfoveal injections of low dose (up to 5x1010 vector genome (vg) per eye, n=5) or high dose (up to 1x1011 vg per eye, n=10) AAV2-hCHM. Patients were evaluated pre- and post-operatively for two years with ophthalmic examinations, multimodal retinal imaging and psychophysical testing. MAIN OUTCOME Measures: visual acuity (VA), perimetry (10-2 protocol), spectral-domain optical coherence tomography (SD-OCT) and short-wavelength fundus autofluorescence (SW-FAF). RESULTS We detected no vector-related or systemic toxicities. VA returned to within 15 letters of baseline in all but two patients (one developed acute foveal thinning, another patient, a macular hole); the rest showed no gross changes in foveal structure at two years. There were no significant differences between intervention and control eyes in mean light-adapted sensitivity by perimetry, or in the lateral extent of retinal pigment epithelium (RPE) relative preservation by SD-OCT and SW-FAF. Microperimetry showed non-significant (<3SD of the intervisit variability) gains in sensitivity in some locations and participants in the intervention eye. There were no obvious dose-dependent relationships. CONCLUSIONS VA was within 15 letters of baseline after the subfoveal AAV2-hCHM injections in 13/15 (87%) of the patients. Acute foveal thinning with unchanged perifoveal function in one patient and macular hole in a second suggests foveal vulnerability to the subretinal injections. Longer observation intervals will help establish the significance of the minor differences in sensitivities and rate of disease progression observed between intervention and control eyes.
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Amato A, Arrigo A, Aragona E, Manitto MP, Saladino A, Bandello F, Battaglia Parodi M. Gene Therapy in Inherited Retinal Diseases: An Update on Current State of the Art. Front Med (Lausanne) 2021; 8:750586. [PMID: 34722588 PMCID: PMC8553993 DOI: 10.3389/fmed.2021.750586] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 12/11/2022] Open
Abstract
Background: Gene therapy cannot be yet considered a far perspective, but a tangible therapeutic option in the field of retinal diseases. Although still confined in experimental settings, the preliminary results are promising and provide an overall scenario suggesting that we are not so far from the application of gene therapy in clinical settings. The main aim of this review is to provide a complete and updated overview of the current state of the art and of the future perspectives of gene therapy applied on retinal diseases. Methods: We carefully revised the entire literature to report all the relevant findings related to the experimental procedures and the future scenarios of gene therapy applied in retinal diseases. A clinical background and a detailed description of the genetic features of each retinal disease included are also reported. Results: The current literature strongly support the hope of gene therapy options developed for retinal diseases. Although being considered in advanced stages of investigation for some retinal diseases, such as choroideremia (CHM), retinitis pigmentosa (RP), and Leber's congenital amaurosis (LCA), gene therapy is still quite far from a tangible application in clinical practice for other retinal diseases. Conclusions: Gene therapy is an extremely promising therapeutic tool for retinal diseases. The experimental data reported in this review offer a strong hope that gene therapy will be effectively available in clinical practice in the next years.
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Affiliation(s)
- Alessia Amato
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Emanuela Aragona
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Maria Pia Manitto
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Andrea Saladino
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, Scientific Institute San Raffaele Hospital, Milan, Italy
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Kalatzis V, Roux AF, Meunier I. Molecular Therapy for Choroideremia: Pre-clinical and Clinical Progress to Date. Mol Diagn Ther 2021; 25:661-675. [PMID: 34661884 DOI: 10.1007/s40291-021-00558-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 12/01/2022]
Abstract
Choroideremia is an inherited retinal disease characterised by a degeneration of the light-sensing photoreceptors, supporting retinal pigment epithelium and underlying choroid. Patients present with the same symptoms as those with classic rod-cone dystrophy: (1) night blindness early in life; (2) progressive peripheral visual field loss, and (3) central vision decline with a slow progression to legal blindness. Choroideremia is monogenic and caused by mutations in CHM. Eight clinical trials (three phase 1/2, four phase 2, and one phase 3) have started (four of which are already finished) to evaluate the therapeutic efficacy of gene supplementation mediated by subretinal delivery of an adeno-associated virus serotype 2 (AAV2/2) vector expressing CHM. Furthermore, one phase 1 clinical trial has been initiated to evaluate the efficiency of a novel AAV variant to deliver CHM to the outer retina following intravitreal delivery. Lastly, a non-viral-mediated CHM replacement strategy is currently under development, which could lead to a future clinical trial. Here, we summarise the rationale behind these various studies, as well as any results published to date. The diversity of these trials currently places choroideremia at the forefront of the retinal gene therapy field. As a consequence, the trial outcomes, regardless of the results, have the potential to change the landscape of gene supplementation for inherited retinal diseases.
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Affiliation(s)
- Vasiliki Kalatzis
- Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm U1298, Hôpital St Eloi, 80 Avenue Augustin Fliche, 34091, Montpellier, France.
| | - Anne-Françoise Roux
- Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm U1298, Hôpital St Eloi, 80 Avenue Augustin Fliche, 34091, Montpellier, France.,Molecular Genetics Laboratory, Univ Montpellier, CHU Montpellier, Montpellier, France
| | - Isabelle Meunier
- Institute for Neurosciences of Montpellier, Univ Montpellier, Inserm U1298, Hôpital St Eloi, 80 Avenue Augustin Fliche, 34091, Montpellier, France.,National Reference Centre for Inherited Sensory Diseases, University of Montpellier, CHU Montpellier, Montpellier, France
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Shughoury A, Ciulla TA, Bakall B, Pennesi ME, Kiss S, Cunningham ET. Genes and Gene Therapy in Inherited Retinal Disease. Int Ophthalmol Clin 2021; 61:3-45. [PMID: 34584043 DOI: 10.1097/iio.0000000000000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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Zeitz C, Nassisi M, Laurent-Coriat C, Andrieu C, Boyard F, Condroyer C, Démontant V, Antonio A, Lancelot ME, Frederiksen H, Kloeckener-Gruissem B, El-Shamieh S, Zanlonghi X, Meunier I, Roux AF, Mohand-Saïd S, Sahel JA, Audo I. CHM mutation spectrum and disease: An update at the time of human therapeutic trials. Hum Mutat 2021; 42:323-341. [PMID: 33538369 DOI: 10.1002/humu.24174] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/21/2020] [Accepted: 01/20/2021] [Indexed: 12/15/2022]
Abstract
Choroideremia is an X-linked inherited retinal disorder (IRD) characterized by the degeneration of retinal pigment epithelium, photoreceptors, choriocapillaris and choroid affecting males with variable phenotypes in female carriers. Unlike other IRD, characterized by a large clinical and genetic heterogeneity, choroideremia shows a specific phenotype with causative mutations in only one gene, CHM. Ongoing gene replacement trials raise further interests in this disorder. We describe here the clinical and genetic data from a French cohort of 45 families, 25 of which carry novel variants, in the context of 822 previously reported choroideremia families. Most of the variants represent loss-of-function mutations with eleven families having large (i.e. ≥6 kb) genomic deletions, 18 small insertions, deletions or insertion deletions, six showing nonsense variants, eight splice site variants and two missense variants likely to affect splicing. Similarly, 822 previously published families carry mostly loss-of-function variants. Recurrent variants are observed worldwide, some of which linked to a common ancestor, others arisen independently in specific CHM regions prone to mutations. Since all exons of CHM may harbor variants, Sanger sequencing combined with quantitative polymerase chain reaction or multiplex ligation-dependent probe amplification experiments are efficient to achieve the molecular diagnosis in patients with typical choroideremia features.
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Affiliation(s)
- Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Marco Nassisi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Camille Andrieu
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France
| | - Fiona Boyard
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Vanessa Démontant
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Helen Frederiksen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Barbara Kloeckener-Gruissem
- Institute of Medical Molecular Genetics, University of Zurich, Schlieren, Switzerland.,Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Said El-Shamieh
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon
| | - Xavier Zanlonghi
- Clinique Pluridisciplinaire Jules Verne, Institut Ophtalmologique de l'Ouest, Nantes, France
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Montpellier, France.,Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France
| | - Anne-Françoise Roux
- Laboratoire de Génétique Moléculaire, CHU de Montpellier, Université de Montpellier, Montpellier, France
| | - Saddek Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Académie des Sciences-Institut de France, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC1423, Paris, France.,Department of Genetics, UCL-Institute of Ophthalmology, London, UK
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Abstract
PURPOSE Choroideremia (CHM) is a rare inherited retinal degeneration resulting from mutation of the CHM gene, which results in absence of functional Rab escort protein 1 (REP1). We evaluated retinal gene therapy with an adeno-associated virus vector that used to deliver a functional version of the CHM gene (AAV2-REP1). METHODS THOR (NCT02671539) is a Phase 2, open-label, single-center, randomized study. Six male patients (51-60 years) with CHM received AAV2-REP1, by a single 0.1-mL subretinal injection of 10 genome particles during vitrectomy. Twelve-month data are reported. RESULTS In study eyes, 4 patients experienced minor changes in best-corrected visual acuity (-4 to +1 Early Treatment Diabetic Retinopathy Study [ETDRS] letters); one gained 17 letters and another lost 14 letters. Control eyes had changes of -2 to +4 letters. In 5/6 patients, improvements in mean (95% confidence intervals) retinal sensitivity (2.3 [4.0] dB), peak retinal sensitivity (2.8 [3.5] dB), and gaze fixation area (-36.1 [66.9] deg) were recorded. Changes in anatomical endpoints were similar between study and control eyes. Adverse events were consistent with the surgical procedure. CONCLUSION Gene therapy with AAV2-REP1 can maintain, and in some cases, improve, visual acuity in CHM. Longer term follow-up is required to establish whether these benefits are maintained.
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12
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Abstract
PURPOSE Choroideremia is an incurable, X-linked, recessive retinal dystrophy caused by loss of function mutations in the CHM gene. It is estimated to affect approximately 1 in 50,000 male patients. It is characterized by progressive degeneration of the retinal pigment epithelium, choroid, and photoreceptors, resulting in visual impairment and blindness. There is an unmet need in choroideremia, because currently, there are no approved treatments available for patients with the disease. METHODS We review the patient journey, societal impact, and emerging treatments for patients with choroideremia. RESULTS Its relative rarity and similarities with other retinal diseases in early years mean that diagnosis of choroideremia can often be delayed. Furthermore, its impact on affected individuals, and wider society, is also likely underestimated. AAV2-mediated gene therapy is an investigational treatment that aims to replace the faulty CHM gene. Early-phase studies reported potentially important visual acuity gains and maintenance of vision in some patients, and a large Phase 3 program is now underway. CONCLUSION Choroideremia is a disease with a significant unmet need. Interventions that can treat progression of the disease and improve visual and functional outcomes have the potential to reduce health care costs and enhance patient quality of life.
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13
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Sinha D, Steyer B, Shahi PK, Mueller KP, Valiauga R, Edwards KL, Bacig C, Steltzer SS, Srinivasan S, Abdeen A, Cory E, Periyasamy V, Siahpirani AF, Stone EM, Tucker BA, Roy S, Pattnaik BR, Saha K, Gamm DM. Human iPSC Modeling Reveals Mutation-Specific Responses to Gene Therapy in a Genotypically Diverse Dominant Maculopathy. Am J Hum Genet 2020; 107:278-292. [PMID: 32707085 DOI: 10.1016/j.ajhg.2020.06.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 06/12/2020] [Indexed: 12/26/2022] Open
Abstract
Dominantly inherited disorders are not typically considered to be therapeutic candidates for gene augmentation. Here, we utilized induced pluripotent stem cell-derived retinal pigment epithelium (iPSC-RPE) to test the potential of gene augmentation to treat Best disease, a dominant macular dystrophy caused by over 200 missense mutations in BEST1. Gene augmentation in iPSC-RPE fully restored BEST1 calcium-activated chloride channel activity and improved rhodopsin degradation in an iPSC-RPE model of recessive bestrophinopathy as well as in two models of dominant Best disease caused by different mutations in regions encoding ion-binding domains. A third dominant Best disease iPSC-RPE model did not respond to gene augmentation, but showed normalization of BEST1 channel activity following CRISPR-Cas9 editing of the mutant allele. We then subjected all three dominant Best disease iPSC-RPE models to gene editing, which produced premature stop codons specifically within the mutant BEST1 alleles. Single-cell profiling demonstrated no adverse perturbation of retinal pigment epithelium (RPE) transcriptional programs in any model, although off-target analysis detected a silent genomic alteration in one model. These results suggest that gene augmentation is a viable first-line approach for some individuals with dominant Best disease and that non-responders are candidates for alternate approaches such as gene editing. However, testing gene editing strategies for on-target efficiency and off-target events using personalized iPSC-RPE model systems is warranted. In summary, personalized iPSC-RPE models can be used to select among a growing list of gene therapy options to maximize safety and efficacy while minimizing time and cost. Similar scenarios likely exist for other genotypically diverse channelopathies, expanding the therapeutic landscape for affected individuals.
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Affiliation(s)
- Divya Sinha
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Benjamin Steyer
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Pawan K Shahi
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Katherine P Mueller
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Rasa Valiauga
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Cole Bacig
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Stephanie S Steltzer
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Sandhya Srinivasan
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Amr Abdeen
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Evan Cory
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Viswesh Periyasamy
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | | | - Edwin M Stone
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Budd A Tucker
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Sushmita Roy
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biostatistics, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Bikash R Pattnaik
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53792, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Krishanu Saha
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - David M Gamm
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI 53705, USA; Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI 53705, USA.
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14
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Garafalo AV, Cideciyan AV, Héon E, Sheplock R, Pearson A, WeiYang Yu C, Sumaroka A, Aguirre GD, Jacobson SG. Progress in treating inherited retinal diseases: Early subretinal gene therapy clinical trials and candidates for future initiatives. Prog Retin Eye Res 2020; 77:100827. [PMID: 31899291 PMCID: PMC8714059 DOI: 10.1016/j.preteyeres.2019.100827] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/21/2019] [Accepted: 12/26/2019] [Indexed: 12/15/2022]
Abstract
Due to improved phenotyping and genetic characterization, the field of 'incurable' and 'blinding' inherited retinal diseases (IRDs) has moved substantially forward. Decades of ascertainment of IRD patient data from Philadelphia and Toronto centers illustrate the progress from Mendelian genetic types to molecular diagnoses. Molecular genetics have been used not only to clarify diagnoses and to direct counseling but also to enable the first clinical trials of gene-based treatment in these diseases. An overview of the recent reports of gene augmentation clinical trials by subretinal injections is used to reflect on the reasons why there has been limited success in this early venture into therapy. These first-in human experiences have taught that there is a need for advancing the techniques of delivery of the gene products - not only for refining further subretinal trials, but also for evaluating intravitreal delivery. Candidate IRDs for intravitreal gene delivery are then suggested to illustrate some of the disorders that may be amenable to improvement of remaining central vision with the least photoreceptor trauma. A more detailed understanding of the human IRDs to be considered for therapy and the calculated potential for efficacy should be among the routine prerequisites for initiating a clinical trial.
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Affiliation(s)
- Alexandra V Garafalo
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Rebecca Sheplock
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Alexander Pearson
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Caberry WeiYang Yu
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Alexander Sumaroka
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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15
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Gene Therapy in Retinal Dystrophies. Int J Mol Sci 2019; 20:ijms20225722. [PMID: 31739639 PMCID: PMC6888000 DOI: 10.3390/ijms20225722] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/13/2019] [Accepted: 11/13/2019] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal dystrophies (IRDs) are a group of clinically and genetically heterogeneous degenerative disorders. To date, mutations have been associated with IRDs in over 270 disease genes, but molecular diagnosis still remains elusive in about a third of cases. The methodologic developments in genome sequencing techniques that we have witnessed in this last decade have represented a turning point not only in diagnosis and prognosis but, above all, in the identification of new therapeutic perspectives. The discovery of new disease genes and pathogenetic mechanisms underlying IRDs has laid the groundwork for gene therapy approaches. Several clinical trials are ongoing, and the recent approval of Luxturna, the first gene therapy product for Leber congenital amaurosis, marks the beginning of a new era. Due to its anatomical and functional characteristics, the retina is the organ of choice for gene therapy, although there are quite a few difficulties in the translational approaches from preclinical models to humans. In the first part of this review, an overview of the current knowledge on methodological issues and future perspectives of gene therapy applied to IRDs is discussed; in the second part, the state of the art of clinical trials on the gene therapy approach in IRDs is illustrated.
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16
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McDougald DS, Duong TT, Palozola KC, Marsh A, Papp TE, Mills JA, Zhou S, Bennett J. CRISPR Activation Enhances In Vitro Potency of AAV Vectors Driven by Tissue-Specific Promoters. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 13:380-389. [PMID: 31024980 PMCID: PMC6477656 DOI: 10.1016/j.omtm.2019.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/21/2019] [Indexed: 12/28/2022]
Abstract
Validation of gene transfer vectors containing tissue-specific promoters in cell-based functional assays poses a formidable challenge for gene therapy product development. Here, we describe a novel approach based on CRISPR/dCas9 transcriptional activation to achieve robust transgene expression from transgene cassettes containing tissue or cell type-specific promoters after infection with AAV vectors in cell-based systems. Guide RNA sequences targeting two promoters that are highly active within mammalian photoreceptors were screened in a novel promoter activation assay. Using this screen, we generated and characterized stable cell lines that co-express dCas9.VPR and top-performing guide RNA candidates. These cells exhibit potent activation of proviral plasmids after transfection or after infection with AAV vectors delivering transgene cassettes carrying photoreceptor-specific promoters. In addition, we interrogated mechanisms to optimize this platform through the addition of multiple guide RNA sequences and co-expression of the universal adeno-associated virus receptor (AAVR). Collectively, this investigation identifies a rapid and broadly applicable strategy to enhance in vitro expression and to evaluate potency of AAV vectors that rely upon cell or tissue-specific regulatory elements.
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Affiliation(s)
- Devin S McDougald
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Thu T Duong
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Katherine C Palozola
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anson Marsh
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tyler E Papp
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jason A Mills
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shangzhen Zhou
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Comparative AAV-eGFP Transgene Expression Using Vector Serotypes 1-9, 7m8, and 8b in Human Pluripotent Stem Cells, RPEs, and Human and Rat Cortical Neurons. Stem Cells Int 2019; 2019:7281912. [PMID: 30800164 PMCID: PMC6360060 DOI: 10.1155/2019/7281912] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 10/30/2018] [Accepted: 11/16/2018] [Indexed: 01/03/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV), produced from a nonpathogenic parvovirus, has become an increasing popular vector for gene therapy applications in human clinical trials. However, transduction and transgene expression of rAAVs can differ across in vitro and ex vivo cellular transduction strategies. This study compared 11 rAAV serotypes, carrying one reporter transgene cassette containing a cytomegalovirus immediate-early enhancer (eCMV) and chicken beta actin (CBA) promoter driving the expression of an enhanced green-fluorescent protein (eGFP) gene, which was transduced into four different cell types: human iPSC, iPSC-derived RPE, iPSC-derived cortical, and dissociated embryonic day 18 rat cortical neurons. Each cell type was exposed to three multiplicity of infections (MOI: 1E4, 1E5, and 1E6 vg/cell). After 24, 48, 72, and 96 h posttransduction, GFP-expressing cells were examined and compared across dosage, time, and cell type. Retinal pigmented epithelium showed highest AAV-eGFP expression and iPSC cortical the lowest. At an MOI of 1E6 vg/cell, all serotypes show measurable levels of AAV-eGFP expression; moreover, AAV7m8 and AAV6 perform best across MOI and cell type. We conclude that serotype tropism is not only capsid dependent but also cell type plays a significant role in transgene expression dynamics.
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18
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Ong T, Pennesi ME, Birch DG, Lam BL, Tsang SH. Adeno-Associated Viral Gene Therapy for Inherited Retinal Disease. Pharm Res 2019; 36:34. [PMID: 30617669 PMCID: PMC6534121 DOI: 10.1007/s11095-018-2564-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/13/2018] [Indexed: 01/17/2023]
Abstract
Inherited retinal diseases (IRDs) are a group of rare, heterogenous eye disorders caused by gene mutations that result in degeneration of the retina. There are currently limited treatment options for IRDs; however, retinal gene therapy holds great promise for the treatment of different forms of inherited blindness. One such IRD for which gene therapy has shown positive initial results is choroideremia, a rare, X-linked degenerative disorder of the retina and choroid. Mutation of the CHM gene leads to an absence of functional Rab escort protein 1 (REP1), which causes retinal pigment epithelium cell death and photoreceptor degeneration. The condition presents in childhood as night blindness, followed by progressive constriction of visual fields, generally leading to vision loss in early adulthood and total blindness thereafter. A recently developed adeno-associated virus-2 (AAV2) vector construct encoding REP1 (AAV2-REP1) has been shown to deliver a functional version of the CHM gene into the retinal pigment epithelium and photoreceptor cells. Phase 1 and 2 studies of AAV2-REP1 in patients with choroideremia have produced encouraging results, suggesting that it is possible not only to slow or stop the decline in vision following treatment with AAV2-REP1, but also to improve visual acuity in some patients.
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Affiliation(s)
- Tuyen Ong
- Nightstar Therapeutics, 203 Crescent Street, Suite 303, Waltham, Massachusetts, 02453, USA.
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - David G Birch
- Retina Foundation of the Southwest, Dallas, Texas, USA
| | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Stephen H Tsang
- Department of Ophthalmology and of Pathology and Cell Biology, Columbia University, New York, New York, USA
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19
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A Mini Review: Moving iPSC-Derived Retinal Subtypes Forward for Clinical Applications for Retinal Degenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:557-561. [PMID: 31884670 DOI: 10.1007/978-3-030-27378-1_91] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Patient-derived human-induced pluripotent stem cells (iPSCs) have been critical in advancing our understanding of the underlying mechanisms of numerous retinal disorders. Many of these retinal disorders have no effective treatment and result in severe visual impairment and even blindness. Among the retinal degenerative diseases modeled by iPSCs are age-related macular degeneration (AMD), glaucoma, Leber congenital amaurosis (LCA), retinitis pigmentosa (RP), and autosomal dominant retinitis pigmentosa (adRP). In addition to studying retinal disease ontogenesis and pathology, hiPSCs have clinical and pharmacological applications, such as developing drug screening and gene therapy approaches and new cell-based clinical treatments. Recent studies have primarily focused on three retinal cell fates - retinal pigmented epithelium cells (RPE), retinal ganglion cells (RGCs), and photoreceptor cells - and have demonstrated that hiPSCs have great potential for increasing our knowledge of and developing treatments for retinal degenerative disorders.
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20
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Lam BL, Davis JL, Gregori NZ, MacLaren RE, Girach A, Verriotto JD, Rodriguez B, Rosa PR, Zhang X, Feuer WJ. Choroideremia Gene Therapy Phase 2 Clinical Trial: 24-Month Results. Am J Ophthalmol 2019; 197:65-73. [PMID: 30240725 DOI: 10.1016/j.ajo.2018.09.012] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 09/09/2018] [Accepted: 09/11/2018] [Indexed: 11/26/2022]
Abstract
PURPOSE To report the final results of a phase 2 high-dose gene therapy clinical trial in choroideremia. METHODS Design: Phase 2 clinical trial. PARTICIPANTS Six men (aged 32-72 years) with genetically-confirmed advanced choroideremia. Patients received subfoveal injection of AAV2-REP1 (1011 genome particles in 0.1 mL) in the worse-sighted eye. OUTCOME MEASURES Primary measure was best-corrected visual acuity (BCVA) change from baseline in the treated eye compared to the untreated eye. Secondary endpoints included change from baseline in microperimetry, fundus autofluorescence, and spectral-domain optical coherence tomography (OCT). Safety evaluations included adverse events, viral shedding in body fluids, and vector antibody responses. RESULTS Baseline mean ETDRS BCVA was 65.3 ± 8.8 (SD, range 56-77, 20/32-20/80) letters in the treated eyes and 77.0 ± 4.2 (69-81, 20/25-20/40) letters in the untreated eyes. At 2 years, 1 treated eye improved by 10 letters and another by 5 letters, while 1 untreated eye improved by 4 letters. All other eyes were within 2 letters of baseline. Baseline microperimetry sensitivities in the treated eyes were poor (1.2 ± 2.1 (0, 5.1) dB) and showed no significant change. No serious adverse event occurred. Two patients developed an atrophic retinal hole in a nonfunctioning macular area where baseline OCT showed preexisting thinning. Intraoperative microscope-integrated OCT allowed proper subretinal injection with avoidance of excessive foveal stretching and macular hole formation. CONCLUSIONS Sustained improvement or maintenance of BCVA is achievable in choroideremia with high-dose AAV2-REP1, indicating BCVA is a viable primary outcome in advanced choroideremia. Choroideremia gene therapy delivered with intraoperative OCT has a good safety profile.
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21
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Cehajic Kapetanovic J, Patrício MI, MacLaren RE. Progress in the development of novel therapies for choroideremia. EXPERT REVIEW OF OPHTHALMOLOGY 2019; 14:277-285. [PMID: 32002021 PMCID: PMC6992425 DOI: 10.1080/17469899.2019.1699406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
INTRODUCTION There are no currently approved treatments for choroideremia, an X-linked progressive inherited retinal degeneration that leads to blindness by middle age. Several treatment options are being explored, but with major advances in adeno-associated vector (AAV) gene replacement therapy that has reached phase III clinical trials. AREAS COVERED In this review we discuss new insights into the clinical phenotyping and genetic testing of choroideremia patients, that aid disease characterisation, progression and patient inclusion into clinical trials. Recent advances in in-vitro studies have resulted in the development of functional assays that can be used to confirm the diagnosis in challenging cases and to quantify vector potency for use in clinical trials. We review the progress in current gene therapy trials and some considerations towards gene therapy approval for the treatment of choroideremia. Lastly, we discuss developments in alternative therapies including optogenetics. EXPERT COMMENTARY AAV gene replacement therapy is the most promising treatment strategy for choroideremia, that has developed exponentially over the last few years with a phase III clinical trial now underway. Optogenetics is a promising alternative strategy that might be applicable in late stages of degeneration.
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Affiliation(s)
- Jasmina Cehajic Kapetanovic
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Maria I Patrício
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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22
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Foltz LP, Clegg DO. Patient-derived induced pluripotent stem cells for modelling genetic retinal dystrophies. Prog Retin Eye Res 2018; 68:54-66. [PMID: 30217765 DOI: 10.1016/j.preteyeres.2018.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 09/05/2018] [Accepted: 09/07/2018] [Indexed: 12/22/2022]
Abstract
The human retina is a highly complex tissue that makes up an integral part of our central nervous system. It is astonishing that our retina works seamlessly to provide one of our most critical senses, and it is equally devastating when a disease destroys a portion of the retina and robs people of their vision. After decades of research, scientists are beginning to understand retinal cells in a way that can benefit the millions of individuals suffering from inherited blindness. This understanding has come about in part with the ability to culture human embryonic stem cells and the innovation of induced pluripotent stem cells, which can be cultured from patients and used to model their disease. In this review, we highlight the successes of specific disease modelling studies and resulting molecular discoveries. The greatest strides in cellular modelling have come from mutations in genes with established and well-understood cellular functions in the context of the retina. We believe that the future of cellular modelling depends on emphasising reproducible production of retinal cell types, demonstrating functional rescue using site-specific programmable nucleases, and shifting towards unbiased screening using next generation sequencing.
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Affiliation(s)
- Leah P Foltz
- Biochemistry and Molecular Biology, University of California, Santa Barbara, CA, USA; Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, CA, USA.
| | - Dennis O Clegg
- Biochemistry and Molecular Biology, University of California, Santa Barbara, CA, USA; Center for Stem Cell Biology and Engineering, University of California, Santa Barbara, CA, USA
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23
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Patrício MI, Barnard AR, Xue K, MacLaren RE. Choroideremia: molecular mechanisms and development of AAV gene therapy. Expert Opin Biol Ther 2018; 18:807-820. [DOI: 10.1080/14712598.2018.1484448] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Maria I Patrício
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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24
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Fu X, Huu VAN, Duan Y, Kermany DS, Valentim CCS, Zhang R, Zhu J, Zhang CL, Sun X, Zhang K. Clinical applications of retinal gene therapies. PRECISION CLINICAL MEDICINE 2018; 1:5-20. [PMID: 35694125 PMCID: PMC8982485 DOI: 10.1093/pcmedi/pby004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Retinal degenerative diseases are a major cause of blindness. Retinal gene therapy is a
trail-blazer in the human gene therapy field, leading to the first FDA approved gene
therapy product for a human genetic disease. The application of Clustered Regularly
Interspaced Short Palindromic Repeat/Cas9 (CRISPR/Cas9)-mediated gene editing technology
is transforming the delivery of gene therapy. We review the history, present, and future
prospects of retinal gene therapy.
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Affiliation(s)
- Xin Fu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Viet Anh Nguyen Huu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Yaou Duan
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Daniel S Kermany
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Carolina C S Valentim
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Runze Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jie Zhu
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Charlotte L Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Xiaodong Sun
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Jiaodong University, Shanghai, China
| | - Kang Zhang
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
- Molecular Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
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25
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DiCarlo JE, Mahajan VB, Tsang SH. Gene therapy and genome surgery in the retina. J Clin Invest 2018; 128:2177-2188. [PMID: 29856367 DOI: 10.1172/jci120429] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Precision medicine seeks to treat disease with molecular specificity. Advances in genome sequence analysis, gene delivery, and genome surgery have allowed clinician-scientists to treat genetic conditions at the level of their pathology. As a result, progress in treating retinal disease using genetic tools has advanced tremendously over the past several decades. Breakthroughs in gene delivery vectors, both viral and nonviral, have allowed the delivery of genetic payloads in preclinical models of retinal disorders and have paved the way for numerous successful clinical trials. Moreover, the adaptation of CRISPR-Cas systems for genome engineering have enabled the correction of both recessive and dominant pathogenic alleles, expanding the disease-modifying power of gene therapies. Here, we highlight the translational progress of gene therapy and genome editing of several retinal disorders, including RPE65-, CEP290-, and GUY2D-associated Leber congenital amaurosis, as well as choroideremia, achromatopsia, Mer tyrosine kinase- (MERTK-) and RPGR X-linked retinitis pigmentosa, Usher syndrome, neovascular age-related macular degeneration, X-linked retinoschisis, Stargardt disease, and Leber hereditary optic neuropathy.
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Affiliation(s)
- James E DiCarlo
- Jonas Children's Vision Care and Bernard and Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, New York, USA
| | - Vinit B Mahajan
- Omics Laboratory, Byers Eye Institute, Department of Ophthalmology, Stanford University, Palo Alto, California, USA.,Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard and Shirlee Brown Glaucoma Laboratory, Columbia Stem Cell Initiative, Departments of Ophthalmology, Pathology and Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, New York, USA
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Xue K, MacLaren RE. Ocular gene therapy for choroideremia: clinical trials and future perspectives. EXPERT REVIEW OF OPHTHALMOLOGY 2018; 13:129-138. [PMID: 31105764 DOI: 10.1080/17469899.2018.1475232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Introduction Gene therapy offers the potential for targeted replacement of single gene defects in inherited retinal degenerations. Areas covered Choroideremia is an X-linked blinding retinal disease resulting from deficiency of the CHM gene product, REP1. The disease represents an ideal target for retinal gene therapy, as it is readily diagnosed in the clinic, relatively homogenous in phenotype and slow progressing, thereby providing a wide therapeutic window for intervention. Ongoing clinical trials of retinal gene therapy for choroideremia using an adeno-associated viral vector have demonstrated safety and early efficacy. We review the clinical characteristics of the disease with a view to interpreting the findings of gene therapy clinical trials and discuss future directions. Expert commentary Choroideremia gene therapy has so far demonstrated good safety profile and early functional visual acuity gains in a proportion of trial participants, which appear to be sustained.
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Affiliation(s)
- Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford & Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford & Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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Patrício MI, Barnard AR, Cox CI, Blue C, MacLaren RE. The Biological Activity of AAV Vectors for Choroideremia Gene Therapy Can Be Measured by In Vitro Prenylation of RAB6A. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2018; 9:288-295. [PMID: 29707603 PMCID: PMC5918179 DOI: 10.1016/j.omtm.2018.03.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/25/2018] [Indexed: 11/23/2022]
Abstract
Choroideremia (CHM) is a rare, X-linked recessive retinal dystrophy caused by mutations in the CHM gene. CHM is ubiquitously expressed in human cells and encodes Rab escort protein 1 (REP1). REP1 plays a key role in intracellular trafficking through the prenylation of Rab GTPases, a reaction that can be reproduced in vitro. With recent advances in adeno-associated virus (AAV) gene therapy for CHM showing gene replacement to be a promising approach, an assay to assess the biological activity of the vectors is of the uttermost importance. Here we sought to compare the response of two Rab proteins, RAB27A and RAB6A, to the incorporation of a biotinylated lipid donor in a prenylation reaction in vitro. First, we found the expression of REP1 to be proportional to the amount of recombinant AAV (rAAV)2/2-REP1 used to transduce the cells. Second, prenylation of RAB6A appeared to be more sensitive to REP1 protein expression than prenylation of RAB27A. Moreover, the method was reproducible in other cell lines. These results support the further development of a prenylation reaction using a biotinylated lipid donor and RAB6A to assess the biological activity of AAV vectors for CHM gene therapy.
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Affiliation(s)
- Maria I Patrício
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Christopher I Cox
- Nightstar Therapeutics, Wellcome Gibbs Building, 215 Euston Road, London, UK
| | - Clare Blue
- Nightstar Therapeutics, Wellcome Gibbs Building, 215 Euston Road, London, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.,National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC), Oxford, UK.,Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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Kannabiran C, Mariappan I. Therapeutic avenues for hereditary forms of retinal blindness. J Genet 2018; 97:341-352. [PMID: 29666355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hereditary retinal diseases, known as retinal degenerations or dystrophies, are a large group of inherited eye disorders resulting in irreversible visual loss and blindness. They develop due to mutations in one or more genes that lead to the death of the retinal photoreceptor cells. Till date, mutations in over 200 genes are known to be associated with all different forms of retinal disorders. The enormous genetic heterogeneity of this group of diseases has posedmany challenges in understanding the mechanisms of disease and in developing suitable therapies. Therapeutic avenues that are being investigated for these disorders include gene therapy to replace the defective gene, treatment with neurotrophic factors to stimulate the growth of photoreceptors, cell replacement therapy, and prosthetic devices that can capture light and transmit electrical signals through retinal neurons to the brain. Several of these are in process of human trials in patients, and have shown safety and efficacy of the treatment. A combination of approaches that involve both gene replacement and cell replacement may be required for optimum benefit.
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Affiliation(s)
- Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, L. V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad 500 034, India.
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Duong TT, Vasireddy V, Ramachandran P, Herrera PS, Leo L, Merkel C, Bennett J, Mills JA. Use of induced pluripotent stem cell models to probe the pathogenesis of Choroideremia and to develop a potential treatment. Stem Cell Res 2018; 27:140-150. [PMID: 29414605 DOI: 10.1016/j.scr.2018.01.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 01/04/2018] [Accepted: 01/06/2018] [Indexed: 12/17/2022] Open
Abstract
Choroideremia (CHM) is a rare monogenic, X-linked recessive inherited retinal degeneration resulting from mutations in the Rab Escort Protein-1 (REP1) encoding CHM gene. The primary retinal cell type leading to CHM is unknown. In this study, we explored the utility of induced pluripotent stem cell-derived models of retinal pigmented epithelium (iPSC-RPE) to study disease pathogenesis and a potential gene-based intervention in four different genetically distinct forms of CHM. A number of abnormal cell biologic, biochemical, and physiologic functions were identified in the CHM mutant cells. We then identified a recombinant adeno-associated virus (AAV) serotype, AAV7m8, that is optimal for both delivering transgenes to iPSC-RPEs as well as to appropriate target cells (RPE cells and rod photoreceptors) in the primate retina. To establish the proof of concept of AAV7m8 mediated CHM gene therapy, we developed AAV7m8.hCHM, which delivers the human CHM cDNA under control of CMV-enhanced chicken β-actin promoter (CßA). Delivery of AAV7m8.hCHM to CHM iPSC-RPEs restored protein prenylation, trafficking and phagocytosis. The results confirm that AAV-mediated delivery of the REP1-encoding gene can rescue defects in CHM iPSC-RPE regardless of the type of disease-causing mutation. The results also extend our understanding of mechanisms involved in the pathophysiology of choroideremia.
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Affiliation(s)
- Thu T Duong
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Vidyullatha Vasireddy
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Pavitra Ramachandran
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Pamela S Herrera
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Lanfranco Leo
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Carrie Merkel
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Jean Bennett
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA
| | - Jason A Mills
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ocular Therapeutics (CAROT), Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, PA 19104, USA.
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Miyata M, Hata M, Ooto S, Ogino K, Gotoh N, Morooka S, Hasegawa T, Hirashima T, Sugahara M, Kuroda Y, Yamashiro K, Yoshimura N. CHOROIDAL AND RETINAL ATROPHY OF BIETTI CRYSTALLINE DYSTROPHY PATIENTS WITH CYP4V2 MUTATIONS COMPARED TO RETINITIS PIGMENTOSA PATIENTS WITH EYS MUTATIONS. Retina 2018; 37:1193-1202. [PMID: 27658286 DOI: 10.1097/iae.0000000000001323] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To compare atrophy of the choroid and retina between Bietti crystalline dystrophy (BCD) patients and EYS-related retinitis pigmentosa (RP) patients with a similar degree of central visual field defects, age, and axial length (AL). METHODS Nine eyes of nine BCD patients with CYP4V2 mutations (BCD group) were examined. Moreover, we selected 10 eyes of 10 RP patients with EYS mutations matched for age, axial length, and mean deviation (measured with the 10-2 SITA standard program; EYS-RP group), and 10 eyes of 10 normal volunteers matched for age and axial length (control group). Macular thicknesses of the choroid and retina were measured via swept-source optical coherence tomography. RESULTS The macular choroid was significantly thinner in the BCD group than in the EYS-RP and control groups, although the thickness did not significantly differ between the EYS-RP and control groups. The macular retina was significantly thinner in the BCD and EYS-RP groups than in the control group, although the thickness did not significantly differ between the BCD and EYS-RP groups at most sites. CONCLUSION Bietti crystalline dystrophy patients with CYP4V2 mutations showed more severe macular choroid atrophy as compared to EYS-related RP patients. These different damage patterns suggest differences in choroidal expression between CYP4V2 and EYS.
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Affiliation(s)
- Manabu Miyata
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Gupta PR, Huckfeldt RM. Gene therapy for inherited retinal degenerations: initial successes and future challenges. J Neural Eng 2017; 14:051002. [DOI: 10.1088/1741-2552/aa7a27] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Battu R, Jeyabalan N, Murthy P, Reddy KS, Schouten JS, Webers CA. Genetic analysis and clinical phenotype of two Indian families with X-linked choroideremia. Indian J Ophthalmol 2017; 64:924-929. [PMID: 28112135 PMCID: PMC5322709 DOI: 10.4103/0301-4738.198866] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Purpose: This study aims to describe the phenotype and genotype of two Indian families affected with X-linked choroideremia (CHM). Materials and Methods: In these two families, the affected individuals and unaffected family members underwent a comprehensive ophthalmic examination including an optical coherence tomography (OCT) and electroretinogram. Blood samples were collected from the families for genetic analysis. Next generation sequencing (NGS) was done using a panel of 184 genes, which covered previously associated genes with retinal dystrophies. Sequencing data were analyzed for the CHM, RPGR, and RP2 genes that have been implicated in CHM and X-linked retinitis pigmentosa (XLRP), respectively. The identified variants were confirmed by Sanger sequencing in available individuals and unrelated controls. Results: In two unrelated male patients, NGS analysis revealed a previously reported 3’-splice site change c.820-1G>C in the CHM gene in the first family and hemizygous mutation c.653G>C (p.Ser218X) in the second family. The asymptomatic family members were carriers for these mutations. Spectral domain-OCT showed loss of outer retina, preservation of the inner retina, and choroidal thinning in the affected males and retinal pigment epithelial changes in the asymptomatic carriers. The identified mutations were not present in 100 controls of Indian origin. There were no potential mutations found in XLRP-associated (RPGR and RP2) genes. Conclusion: This report describes the genotype and phenotype findings in patients with CHM from India. The identified genetic mutation leads to lack of Rab escort protein-1 (REP-1) or affects the production of a REP-1 protein that is likely to cause retinal abnormalities in patients.
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Affiliation(s)
- Rajani Battu
- Department of Vitreoretina, Narayana Nethralaya, Bengaluru, Karnataka, India
| | - Nallathambi Jeyabalan
- Department of Molecular Signaling and Gene Therapy, Grow Research Laboratory, Narayana Nethralaya Foundation, Narayana Nethralaya, Bengaluru, Karnataka, India
| | - Praveen Murthy
- Department of Vitreoretina, Vittala International Institute of Ophthalmology, Bengaluru, Karnataka, India
| | - Kavita S Reddy
- Department of Genetics, Strand Life Sciences Pvt. Limited, Bengaluru, Karnataka, India
| | - Jan Sag Schouten
- Department of Ophthalmology, Maastricht University, Maastricht, The Netherlands
| | - Caroll A Webers
- Department of Ophthalmology, Maastricht University, Maastricht, The Netherlands
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Taking Stock of Retinal Gene Therapy: Looking Back and Moving Forward. Mol Ther 2017; 25:1076-1094. [PMID: 28391961 DOI: 10.1016/j.ymthe.2017.03.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/04/2017] [Accepted: 03/04/2017] [Indexed: 11/23/2022] Open
Abstract
Over the past 20 years, there has been tremendous progress in retinal gene therapy. The safety and efficacy results in one early-onset severe blinding disease may lead to the first gene therapy drug approval in the United States. Here, we review how far the field has come over the past two decades and speculate on the directions that the field will take in the future.
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Abstract
As our understanding of the genetic basis for inherited retinal disease has expanded, gene therapy has advanced into clinical development. When the gene mutations associated with inherited retinal dystrophies were identified, it became possible to create animal models in which individual gene were altered to match the human mutations. The retina of these animals were then characterized to assess whether the mutated genes produced retinal phenotypes characteristic of disease-affected patients. Following the identification of a subpopulation of patients with the affected gene and the development of techniques for the viral gene transduction of retinal cells, it has become possible to deliver a copy of the normal gene into the retinal sites of the mutated genes. When this was performed in animal models of monogenic diseases, at an early stage of retinal degeneration when the affected cells remained viable, successful gene augmentation corrected the structural and functional lesions characteristic of the specific diseases in the areas of the retina that were successfully transduced. These studies provided the essential proof-of-concept needed to advance monogenic gene therapies into clinic development; these therapies include treatments for: Leber's congenital amaurosis type 2, caused by mutations to RPE65, retinoid isomerohydrolase; choroideremia, caused by mutations to REP1, Rab escort protein 1; autosomal recessive Stargardt disease, caused by mutations to ABCA4, the photoreceptor-specific ATP-binding transporter; Usher 1B disease caused by mutations to MYO7A, myosin heavy chain 7; X-linked juvenile retinoschisis caused by mutations to RS1, retinoschisin; autosomal recessive retinitis pigmentosa caused by mutations to MERTK, the proto-oncogene tyrosine-protein kinase MER; Leber's hereditary optic neuropathy caused by mutations to ND4, mitochondrial nicotinamide adenine dinucleotide ubiquinone oxidoreductase (complex I) subunit 4 and achromatopsia, caused by mutations to CNGA3, cyclic nucleotide-gated channel alpha 3 and CNGB3, cyclic nucleotide-gated channel beta 3. This review includes a tabulated summary of treatments for these monogenic retinal dystrophies that have entered into clinical development, as well as a brief summary of the preclinical data that supported their advancement into clinical development.
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Patrício MI, Barnard AR, Orlans HO, McClements ME, MacLaren RE. Inclusion of the Woodchuck Hepatitis Virus Posttranscriptional Regulatory Element Enhances AAV2-Driven Transduction of Mouse and Human Retina. MOLECULAR THERAPY. NUCLEIC ACIDS 2016; 6:198-208. [PMID: 28325286 PMCID: PMC5363497 DOI: 10.1016/j.omtn.2016.12.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/13/2016] [Accepted: 12/13/2016] [Indexed: 11/26/2022]
Abstract
The woodchuck hepatitis virus posttranscriptional regulatory element (WPRE) has been included in the transgene cassette of adeno-associated virus (AAV) in several gene therapy clinical trials, including those for inherited retinal diseases. However, the extent to which WPRE increases transgene expression in the retina is still unclear. To address this question, AAV2 vectors containing a reporter gene with and without WPRE were initially compared in vitro and subsequently in vivo by subretinal delivery in mice. In both instances, the presence of WPRE led to significantly higher levels of transgene expression as measured by fundus fluorescence, western blot, and immunohistochemistry. The two vectors were further compared in human retinal explants derived from patients undergoing clinically indicated retinectomy, where again the presence of WPRE resulted in an enhancement of reporter gene expression. Finally, an analogous approach using a transgene currently employed in a clinical trial for choroideremia delivered similar results both in vitro and in vivo, confirming that the WPRE effect is transgene independent. Our data fully support the inclusion of WPRE in ongoing and future AAV retinal gene therapy trials, where it may allow a therapeutic effect to be achieved at an overall lower dose of vector.
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Affiliation(s)
- Maria I Patrício
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Harry O Orlans
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; Moorfields Eye Hospital, NHS Foundation Trust, London EC1V 2PD, UK
| | - Michelle E McClements
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK; NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford OX3 9DU, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; Moorfields Eye Hospital, NHS Foundation Trust, London EC1V 2PD, UK.
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Constable IJ, Pierce CM, Lai CM, Magno AL, Degli-Esposti MA, French MA, McAllister IL, Butler S, Barone SB, Schwartz SD, Blumenkranz MS, Rakoczy EP. Phase 2a Randomized Clinical Trial: Safety and Post Hoc Analysis of Subretinal rAAV.sFLT-1 for Wet Age-related Macular Degeneration. EBioMedicine 2016; 14:168-175. [PMID: 27865764 PMCID: PMC5161436 DOI: 10.1016/j.ebiom.2016.11.016] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND We present the results of a Phase 2a randomized controlled trial investigating the safety, and secondary endpoints of subretinal rAAV.sFLT-1 gene therapy in patients with active wet age-related macular degeneration (wAMD). METHODS All patients (n=32), (ClinicalTrials.gov; NCT01494805), received ranibizumab injections at baseline and week 4, and thereafter according to prespecified criteria. Patients in the gene therapy group (n=21) received rAAV.sFLT-1 (1×1011vg). All patients were assessed every 4weeks to the week 52 primary endpoint. FINDINGS Ocular adverse events (AEs) in the rAAV.sFLT-1 group were mainly procedure related and self-resolved. All 11 phakic patients in the rAAV.sFLT-1 group showed progression of cataract following vitrectomy. No systemic safety signals were observed and none of the serious AEs were associated with rAAV.sFLT-1. AAV2 capsid was not detected and rAAV.sFLT-1 DNA was detected transiently in the tears of 13 patients. ELISPOT analysis did not identify any notable changes in T-cell response. In the rAAV.sFLT-1 group 12 patients had neutralizing antibodies (nAb) to AAV2. There was no change in sFLT-1 levels in bodily fluids. In the rAAV.sFLT-1 group, Best Corrected Visual Acuity (BCVA) improved by a median of 1.0 (IQR: -3.0 to 9.0) Early Treatment Diabetic Retinopathy Study (ETDRS) letters from baseline compared to a median of -5.0 (IQR: -17.5 to 1.0) ETDRS letters change in the control group. Twelve (57%) patients in the rAAV.sFLT-1 group maintained or improved vision compared to 4 (36%) in the control group. The median number of ranibizumab retreatments was 2.0 (IQR: 1.0 to 6.0) for the gene therapy group compared to 4.0 (IQR: 3.5 to 4.0) for the control group. Interpretation rAAV.sFLT-1 combined with the option for co-treatment appears to be a safe and promising approach to the treatment of wAMD. FUNDING National Health and Medical Research Council of Australia (AP1010405), Lions Eye Institute, Perth Australia, Avalanche Biotechnologies, Menlo Pk, CA, USA.
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Affiliation(s)
- Ian J Constable
- Lions Eye Institute, Nedlands, WA, Australia; Sir Charles Gairdner Hospital, Nedlands, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
| | | | - Chooi-May Lai
- Lions Eye Institute, Nedlands, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
| | | | - Mariapia A Degli-Esposti
- Lions Eye Institute, Nedlands, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
| | - Martyn A French
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia; Department of Clinical Immunology, The University of Western Australia, Crawley, WA, Australia
| | - Ian L McAllister
- Lions Eye Institute, Nedlands, WA, Australia; Sir Charles Gairdner Hospital, Nedlands, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia
| | - Steve Butler
- Avalanche Biotechnologies, Inc., Menlo Park, CA, USA
| | | | | | - Mark S Blumenkranz
- Byers Eye Institute, Stanford Department of Ophthalmology, Palo Alto, CA, USA
| | - Elizabeth P Rakoczy
- Lions Eye Institute, Nedlands, WA, Australia; Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, WA, Australia.
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Adeno-associated virus-mediated CASQ2 delivery rescues phenotypic alterations in a patient-specific model of recessive catecholaminergic polymorphic ventricular tachycardia. Cell Death Dis 2016; 7:e2393. [PMID: 27711080 PMCID: PMC5133973 DOI: 10.1038/cddis.2016.304] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 08/01/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022]
Abstract
Catecholaminergic Polymorphic Ventricular Tachycardia type 2 (CPVT2) is a highly lethal recessive arrhythmogenic disease caused by mutations in the calsequestrin-2 (CASQ2) gene. We have previously demonstrated that viral transfer of the wild-type (WT) CASQ2 gene prevents the development of CPVT2 in a genetically induced mouse model of the disease homozygous carrier of the R33Q mutation. In the present study, we investigated the efficacy of the virally mediated gene therapy in cardiomyocytes (CMs) differentiated from induced pluripotent stem cells (iPSCs) obtained from a patient carrying the homozygous CASQ2-G112+5X mutation. To this end, we infected cells with an Adeno-Associated Viral vector serotype 9 (AAV9) encoding the human CASQ2 gene (AAV9-hCASQ2). Administration of the human WT CASQ2 gene was capable and sufficient to restore the physiological expression of calsequestrin-2 protein and to rescue functional defects of the patient-specific iPSC-derived CMs. Indeed, after viral gene transfer, we observed a remarkable decrease in the percentage of delayed afterdepolarizations (DADs) developed by the diseased CMs upon adrenergic stimulation, the calcium transient amplitude was re-established and the density and duration of calcium sparks were normalized. We therefore demonstrate the efficacy of the AAV9-mediated gene replacement therapy for CPVT2 in a human cardiac-specific model system, supporting the view that the gene-therapy tested is curative in models with different human mutations of CPVT.
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Gopinath C, Nathar TJ, Ghosh A, Hickstein DD, Nelson EJR. Contemporary Animal Models For Human Gene Therapy Applications. Curr Gene Ther 2016; 15:531-40. [PMID: 26415576 DOI: 10.2174/1566523215666150929110424] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/02/2015] [Accepted: 09/08/2015] [Indexed: 01/18/2023]
Abstract
Over the past three decades, gene therapy has been making considerable progress as an alternative strategy in the treatment of many diseases. Since 2009, several studies have been reported in humans on the successful treatment of various diseases. Animal models mimicking human disease conditions are very essential at the preclinical stage before embarking on a clinical trial. In gene therapy, for instance, they are useful in the assessment of variables related to the use of viral vectors such as safety, efficacy, dosage and localization of transgene expression. However, choosing a suitable disease-specific model is of paramount importance for successful clinical translation. This review focuses on the animal models that are most commonly used in gene therapy studies, such as murine, canine, non-human primates, rabbits, porcine, and a more recently developed humanized mice. Though small and large animals both have their own pros and cons as disease-specific models, the choice is made largely based on the type and length of study performed. While small animals with a shorter life span could be well-suited for degenerative/aging studies, large animals with longer life span could suit longitudinal studies and also help with dosage adjustments to maximize therapeutic benefit. Recently, humanized mice or mouse-human chimaeras have gained interest in the study of human tissues or cells, thereby providing a more reliable understanding of therapeutic interventions. Thus, animal models are of great importance with regard to testing new vector technologies in vivo for assessing safety and efficacy prior to a gene therapy clinical trial.
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Lopez Sanchez M, Crowston J, Mackey D, Trounce I. Emerging Mitochondrial Therapeutic Targets in Optic Neuropathies. Pharmacol Ther 2016; 165:132-52. [DOI: 10.1016/j.pharmthera.2016.06.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Indexed: 12/14/2022]
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Wiley LA, Burnight ER, Drack AV, Banach BB, Ochoa D, Cranston CM, Madumba RA, East JS, Mullins RF, Stone EM, Tucker BA. Using Patient-Specific Induced Pluripotent Stem Cells and Wild-Type Mice to Develop a Gene Augmentation-Based Strategy to Treat CLN3-Associated Retinal Degeneration. Hum Gene Ther 2016; 27:835-846. [PMID: 27400765 DOI: 10.1089/hum.2016.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Juvenile neuronal ceroid lipofuscinosis (JNCL) is a childhood neurodegenerative disease with early-onset, severe central vision loss. Affected children develop seizures and CNS degeneration accompanied by severe motor and cognitive deficits. There is no cure for JNCL, and patients usually die during the second or third decade of life. In this study, independent lines of induced pluripotent stem cells (iPSCs) were generated from two patients with molecularly confirmed mutations in CLN3, the gene mutated in JNCL. Clinical-grade adeno-associated adenovirus serotype 2 (AAV2) carrying the full-length coding sequence of human CLN3 was generated in a U.S. Food and Drug Administration-registered cGMP facility. AAV2-CLN3 was efficacious in restoring full-length CLN3 transcript and protein in patient-specific fibroblasts and iPSC-derived retinal neurons. When injected into the subretinal space of wild-type mice, purified AAV2-CLN3 did not show any evidence of retinal toxicity. This study provides proof-of-principle for initiation of a clinical trial using AAV-mediated gene augmentation for the treatment of children with CLN3-associated retinal degeneration.
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Affiliation(s)
- Luke A Wiley
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Erin R Burnight
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Arlene V Drack
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Bailey B Banach
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Dalyz Ochoa
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Cathryn M Cranston
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Robert A Madumba
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Jade S East
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Robert F Mullins
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Edwin M Stone
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
| | - Budd A Tucker
- Department of Ophthalmology and Visual Sciences, Stephen A. Wynn Institute for Vision Research, Carver College of Medicine, University of Iowa , Iowa City, Iowa
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Personalized Medicine: Cell and Gene Therapy Based on Patient-Specific iPSC-Derived Retinal Pigment Epithelium Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:549-55. [PMID: 26427458 DOI: 10.1007/978-3-319-17121-0_73] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Interest in generating human induced pluripotent stem (iPS) cells for stem cell modeling of diseases has overtaken that of patient-specific human embryonic stem cells due to the ethical, technical, and political concerns associated with the latter. In ophthalmology, researchers are currently using iPS cells to explore various applications, including: (1) modeling of retinal diseases using patient-specific iPS cells; (2) autologous transplantation of differentiated retinal cells that undergo gene correction at the iPS cell stage via gene editing tools (e.g., CRISPR/Cas9, TALENs and ZFNs); and (3) autologous transplantation of patient-specific iPS-derived retinal cells treated with gene therapy. In this review, we will discuss the uses of patient-specific iPS cells for differentiating into retinal pigment epithelium (RPE) cells, uncovering disease pathophysiology, and developing new treatments such as gene therapy and cell replacement therapy via autologous transplantation.
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An Autogenously Regulated Expression System for Gene Therapeutic Ocular Applications. Sci Rep 2015; 5:17105. [PMID: 26597678 PMCID: PMC4656984 DOI: 10.1038/srep17105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 10/26/2015] [Indexed: 12/22/2022] Open
Abstract
The future of treating inherited and acquired genetic diseases will be defined by our ability to introduce transgenes into cells and restore normal physiology. Here we describe an autogenous transgene regulatory system (ARES), based on the bacterial lac repressor, and demonstrate its utility for controlling the expression of a transgene in bacteria, eukaryotic cells, and in the retina of mice. This ARES system is inducible by the small non-pharmacologic molecule, Isopropyl β-D-1-thiogalactopyranoside (IPTG) that has no off-target effects in mammals. Following subretinal injection of an adeno-associated virus (AAV) vector encoding ARES, luciferase expression can be reversibly controlled in the murine retina by oral delivery of IPTG over three induction-repression cycles. The ability to induce transgene expression repeatedly via administration of an oral inducer in vivo, suggests that this type of regulatory system holds great promise for applications in human gene therapy.
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BEST1: the Best Target for Gene and Cell Therapies. Mol Ther 2015; 23:1805-9. [PMID: 26388462 DOI: 10.1038/mt.2015.177] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 09/14/2015] [Indexed: 12/14/2022] Open
Abstract
A retinal pigmented epithelial (RPE) disorder, bestrophinopathy has recently been proven to be amenable to gene and cell-based therapies in preclinical models. RPE disorders and allied retinal degenerations exhibit significant genetic heterogeneity, and diverse mutations can result in similar disease phenotypes. Several RPE disorders have recently become targets for gene therapies in humans. The year 2011 brought a new advance in cell-based therapies, with the Food and Drug Administration approving clinical trials using embryonic stem cells for an RPE disorder known as age-related macular degeneration. Recent studies on induced pluripotent stem (iPS)-RPE generation indicate strong potential for developing patient-specific disease models in vitro, which could eventually enable personalized treatment. This mini-review will briefly highlight the suitability of the retina for gene and cell therapies, the pathophysiology of bestrophinopathy, and the research and treatment opportunities afforded by stem cell and genetic therapies.
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Singh R, Kuai D, Guziewicz KE, Meyer J, Wilson M, Lu J, Smith M, Clark E, Verhoeven A, Aguirre GD, Gamm DM. Pharmacological Modulation of Photoreceptor Outer Segment Degradation in a Human iPS Cell Model of Inherited Macular Degeneration. Mol Ther 2015; 23:1700-1711. [PMID: 26300224 DOI: 10.1038/mt.2015.141] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/23/2015] [Indexed: 12/16/2022] Open
Abstract
Degradation of photoreceptor outer segments (POS) by retinal pigment epithelium (RPE) is essential for vision, and studies have implicated altered POS processing in the pathogenesis of some retinal degenerative diseases. Consistent with this concept, a recently established hiPSC-RPE model of inherited macular degeneration, Best disease (BD), displayed reduced rates of POS breakdown. Herein we utilized this model to determine (i) if disturbances in protein degradation pathways are associated with delayed POS digestion and (ii) whether such defect(s) can be pharmacologically targeted. We found that BD hiPSC-RPE cultures possessed increased protein oxidation, decreased free-ubiquitin levels, and altered rates of exosome secretion, consistent with altered POS processing. Application of valproic acid (VPA) with or without rapamycin increased rates of POS degradation in our model, whereas application of bafilomycin-A1 decreased such rates. Importantly, the negative effect of bafilomycin-A1 could be fully reversed by VPA. The utility of hiPSC-RPE for VPA testing was further evident following examination of its efficacy and metabolism in a complementary canine disease model. Our findings suggest that disturbances in protein degradation pathways contribute to the POS processing defect observed in BD hiPSC-RPE, which can be manipulated pharmacologically. These results have therapeutic implications for BD and perhaps other maculopathies.
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Affiliation(s)
- Ruchira Singh
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, USA
| | - David Kuai
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Karina E Guziewicz
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jackelyn Meyer
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Molly Wilson
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jianfeng Lu
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Molly Smith
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Eric Clark
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amelia Verhoeven
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Gustavo D Aguirre
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA; McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, USA; Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, USA.
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Dimopoulos IS, Chan S, MacLaren RE, MacDonald IM. Pathogenic mechanisms and the prospect of gene therapy for choroideremia. Expert Opin Orphan Drugs 2015; 3:787-798. [PMID: 26251765 PMCID: PMC4522943 DOI: 10.1517/21678707.2015.1046434] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Choroideremia is a rare, X-linked disorder recognized by its specific ocular phenotype as a progressive degenerative retinopathy resulting in blindness. New therapeutic approaches, primarily based on genetic mechanisms, have emerged that aim to prevent the progressive vision loss. AREAS COVERED This article will review the research that has progressed incrementally over the past two decades from mapping to gene discovery, uncovering the presumed mechanisms triggering the retinopathy to preclinical testing of potential therapies. EXPERT OPINION While still in an evaluative phase, the introduction of gene replacement as a potential therapy has been greeted with great enthusiasm by patients, advocacy groups and the medical community.
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Affiliation(s)
- Ioannis S Dimopoulos
- University of Alberta, Department of Ophthalmology and Visual Sciences, Edmonton, Alberta, Canada
| | - Stephanie Chan
- University of Alberta, Department of Ophthalmology and Visual Sciences, Edmonton, Alberta, Canada
| | - Robert E MacLaren
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, UK
- Moorfields Eye Hospital Foundation Trust, NIHR Ophthalmology Biomedical Research Centre, London, UK
| | - Ian M MacDonald
- University of Alberta, Department of Ophthalmology and Visual Sciences, Edmonton, Alberta, Canada
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Vasireddy V, Mills JA, Gaddameedi R, Basner-Tschakarjan E, Kohnke M, Black AD, Alexandrov K, Zhou S, Maguire AM, Chung DC, Mac H, Sullivan L, Gadue P, Bennicelli JL, French DL, Bennett J. Correction: AAV-Mediated Gene Therapy for Choroideremia: Preclinical Studies in Personalized Models. PLoS One 2015; 10:e0129982. [PMID: 26090960 PMCID: PMC4474960 DOI: 10.1371/journal.pone.0129982] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
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Bennett J. My career path for developing gene therapy for blinding diseases: the importance of mentors, collaborators, and opportunities. Hum Gene Ther 2015; 25:663-70. [PMID: 25136912 DOI: 10.1089/hum.2014.2529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Jean Bennett
- Department of Ophthalmology and Center for Advanced Retinal and Ophthalmic Therapeutics, Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA 19104
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Nguyen HV, Li Y, Tsang SH. Patient-Specific iPSC-Derived RPE for Modeling of Retinal Diseases. J Clin Med 2015; 4:567-78. [PMID: 26239347 PMCID: PMC4470156 DOI: 10.3390/jcm4040567] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/26/2015] [Accepted: 03/03/2015] [Indexed: 11/16/2022] Open
Abstract
Inherited retinal diseases, such as age-related macular degeneration and retinitis pigmentosa, are the leading cause of blindness in the developed world. Currently, treatments for these conditions are limited. Recently, considerable attention has been given to the possibility of using patient-specific induced pluripotent stem cells (iPSCs) as a treatment for these conditions. iPSCs reprogrammed from adult somatic cells offer the possibility of generating patient-specific cell lines in vitro. In this review, we will discuss the current literature pertaining to iPSC modeling of retinal disease, gene therapy of iPSC-derived retinal pigmented epithelium (RPE) cells, and retinal transplantation. We will focus on the use of iPSCs created from patients with inherited eye diseases for testing the efficacy of gene or drug-based therapies, elucidating previously unknown mechanisms and pathways of disease, and as a source of autologous cells for cell replacement.
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Affiliation(s)
- Huy V Nguyen
- College of Physicians and Surgeons, Columbia University, 100 Haven Ave, Apt 14B, New York, NY 10032, USA.
| | - Yao Li
- Department of Ophthalmology, Columbia University, 635 W 165th St, New York, NY 10032, USA.
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University, 635 W 165th St, New York, NY 10032, USA.
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Black A, Vasireddy V, Chung DC, Maguire AM, Gaddameedi R, Tolmachova T, Seabra M, Bennett J. Adeno-associated virus 8-mediated gene therapy for choroideremia: preclinical studies in in vitro and in vivo models. J Gene Med 2015; 16:122-30. [PMID: 24962736 DOI: 10.1002/jgm.2768] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/04/2014] [Accepted: 06/16/2014] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Choroideremia (CHM) is a slowly progressive X-linked retinal degeneration that results in a loss of photoreceptors, retinal pigment epithelium and choroid. CHM, the gene implicated in choroideremia, encodes Rab escort protein-1 (REP-1), which is involved in the post-translational activation via prenylation of Rab proteins. METHODS We evaluated AAV8.CBA.hCHM, a recombinant adeno-associated virus serotype 8 (rAAV8) vector, which targets retinal cells efficiently, for both therapeutic effect and safety in vitro and in vivo in a murine model. In vitro studies included western blot analyses and prenylation assays. In vivo studies included ophthalmoscopy, pupillometry, histology and immunofluorescence analysis. RESULTS Infection with AAV8.CBA.hCHM induced the expression of REP-1 protein in a dose-responsive fashion. Transduction with AAV8.CBA.hCHM reverses the biochemical and pathogenetic defects in CHM both in vitro and in vivo and showed no safety concerns in the in vivo investigations performed in the present study. CONCLUSIONS AAV8 is a promising vector for human clinical gene therapy trials for choroideremia.
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Affiliation(s)
- Aaron Black
- F.M. Kirby Center for Molecular Ophthalmology and Center for Advanced Retinal and Ophthalmic Therapeutics, Scheie Eye Institute, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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