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Chen M, Wang Y, Dalal R, Du J, Vollrath D. Alternative oxidase blunts pseudohypoxia and photoreceptor degeneration due to RPE mitochondrial dysfunction. Proc Natl Acad Sci U S A 2024; 121:e2402384121. [PMID: 38865272 PMCID: PMC11194566 DOI: 10.1073/pnas.2402384121] [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: 02/05/2024] [Accepted: 05/15/2024] [Indexed: 06/14/2024] Open
Abstract
Loss of mitochondrial electron transport complex (ETC) function in the retinal pigment epithelium (RPE) in vivo results in RPE dedifferentiation and progressive photoreceptor degeneration, and has been implicated in the pathogenesis of age-related macular degeneration. Xenogenic expression of alternative oxidases in mammalian cells and tissues mitigates phenotypes arising from some mitochondrial electron transport defects, but can exacerbate others. We expressed an alternative oxidase from Ciona intestinalis (AOX) in ETC-deficient murine RPE in vivo to assess the retinal consequences of stimulating coenzyme Q oxidation and respiration without ATP generation. RPE-restricted expression of AOX in this context is surprisingly beneficial. This focused intervention mitigates RPE mTORC1 activation, dedifferentiation, hypertrophy, stress marker expression, pseudohypoxia, and aerobic glycolysis. These RPE cell autonomous changes are accompanied by increased glucose delivery to photoreceptors with attendant improvements in photoreceptor structure and function. RPE-restricted AOX expression normalizes accumulated levels of succinate and 2-hydroxyglutarate in ETC-deficient RPE, and counteracts deficiencies in numerous neural retinal metabolites. These features can be attributed to the activation of mitochondrial inner membrane flavoproteins such as succinate dehydrogenase and proline dehydrogenase, and alleviation of inhibition of 2-oxyglutarate-dependent dioxygenases such as prolyl hydroxylases and epigenetic modifiers. Our work underscores the importance to outer retinal health of coenzyme Q oxidation in the RPE and identifies a metabolic network critical for photoreceptor survival in the context of RPE mitochondrial dysfunction.
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Affiliation(s)
- Ming Chen
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA94305
| | - Yekai Wang
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV26506
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA94305
| | - Jianhai Du
- Department of Ophthalmology and Visual Sciences, West Virginia University, Morgantown, WV26506
- Department of Biochemistry and Molecular Medicine, West Virginia University, Morgantown, WV26506
| | - Douglas Vollrath
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA94305
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA94305
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2
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Chou TH, Hao Z, Alba D, Lazo A, Gallo Afflitto G, Eastwood JD, Porciatti V, Guy J, Yu H. Mitochondrially Targeted Gene Therapy Rescues Visual Loss in a Mouse Model of Leber's Hereditary Optic Neuropathy. Int J Mol Sci 2023; 24:17068. [PMID: 38069388 PMCID: PMC10707051 DOI: 10.3390/ijms242317068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 11/26/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a common mitochondrial genetic disease, causing irreversible blindness in young individuals. Current treatments are inadequate, and there is no definitive cure. This study evaluates the effectiveness of delivering wildtype human NADH ubiquinone oxidoreductase subunit 4 (hND4) gene using mito-targeted AAV(MTSAAV) to rescue LHOH mice. We observed a declining pattern in electroretinograms amplitudes as mice aged across all groups (p < 0.001), with significant differences among groups (p = 0.023; Control vs. LHON, p = 0.008; Control vs. Rescue, p = 0.228). Inner retinal thickness and intraocular pressure did not change significantly with age or groups. Compared to LHON mice, those rescued with wildtype hND4 exhibited improved retinal visual acuity (0.29 ± 0.1 cy/deg vs. 0.15 ± 0.1 cy/deg) and increased functional hyperemia response (effect of flicker, p < 0.001, effect of Group, p = 0.004; Interaction Flicker × Group, p < 0.001). Postmortem analysis shows a marked reduction in retinal ganglion cell density in the LHON group compared to the other groups (Effect of Group, p < 0.001, Control vs. LHON, p < 0.001, Control vs. Rescue, p = 0.106). These results suggest that MTSAAV-delivered wildtype hND4 gene rescues, at least in part, visual impairment in an LHON mouse model and has the therapeutic potential to treat this disease.
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Affiliation(s)
| | | | | | | | | | | | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (T.-H.C.); (Z.H.); (D.A.); (A.L.); (G.G.A.); (J.D.E.); (J.G.)
| | | | - Hong Yu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA; (T.-H.C.); (Z.H.); (D.A.); (A.L.); (G.G.A.); (J.D.E.); (J.G.)
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3
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Ling Q, Herstine JA, Bradbury A, Gray SJ. AAV-based in vivo gene therapy for neurological disorders. Nat Rev Drug Discov 2023; 22:789-806. [PMID: 37658167 DOI: 10.1038/s41573-023-00766-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2023] [Indexed: 09/03/2023]
Abstract
Recent advancements in gene supplementation therapy are expanding the options for the treatment of neurological disorders. Among the available delivery vehicles, adeno-associated virus (AAV) is often the favoured vector. However, the results have been variable, with some trials dramatically altering the course of disease whereas others have shown negligible efficacy or even unforeseen toxicity. Unlike traditional drug development with small molecules, therapeutic profiles of AAV gene therapies are dependent on both the AAV capsid and the therapeutic transgene. In this rapidly evolving field, numerous clinical trials of gene supplementation for neurological disorders are ongoing. Knowledge is growing about factors that impact the translation of preclinical studies to humans, including the administration route, timing of treatment, immune responses and limitations of available model systems. The field is also developing potential solutions to mitigate adverse effects, including AAV capsid engineering and designs to regulate transgene expression. At the same time, preclinical research is addressing new frontiers of gene supplementation for neurological disorders, with a focus on mitochondrial and neurodevelopmental disorders. In this Review, we describe the current state of AAV-mediated neurological gene supplementation therapy, including critical factors for optimizing the safety and efficacy of treatments, as well as unmet needs in this field.
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Affiliation(s)
- Qinglan Ling
- Department of Paediatrics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jessica A Herstine
- Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Paediatrics, The Ohio State University, Columbus, OH, USA
| | - Allison Bradbury
- Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH, USA
- Department of Paediatrics, The Ohio State University, Columbus, OH, USA
| | - Steven J Gray
- Department of Paediatrics, UT Southwestern Medical Center, Dallas, TX, USA.
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4
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Velmurugan S, Chou TH, Eastwood JD, Porciatti V, Liu Y, Hauswirth WW, Guy J, Yu H. Comparison of different gene-therapy methods to treat Leber hereditary optic neuropathy in a mouse model. Front Neurosci 2023; 17:1119724. [PMID: 37051151 PMCID: PMC10083341 DOI: 10.3389/fnins.2023.1119724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/13/2023] [Indexed: 03/28/2023] Open
Abstract
IntroductionTherapies for Leber hereditary optic neuropathy (LHON), in common with all disorders caused by mutated mitochondrial DNA, are inadequate. We have developed two gene therapy strategies for the disease: mitochondrial-targeted and allotopic expressed and compared them in a mouse model of LHON.MethodsA LHON mouse model was generated by intravitreal injection of a mitochondrialtargeted Adeno-associated virus (AAV) carrying mutant human NADH dehydrogenase 4 gene (hND4/m.11778G>A) to induce retinal ganglion cell (RGC) degeneration and axon loss, the hallmark of the human disease. We then attempted to rescue those mice using a second intravitreal injection of either mitochondrial-targeted or allotopic expressed wildtype human ND4. The rescue of RGCs and their axons were assessed using serial pattern electroretinogram (PERG) and transmission electron microscopy.ResultsCompared to non-rescued LHON controls where PERG amplitude was much reduced, both strategies significantly preserved PERG amplitude over 15 months. However, the rescue effect was more marked with mitochondrial-targeted therapy than with allotopic therapy (p = 0.0128). Post-mortem analysis showed that mitochondrial-targeted human ND4 better preserved small axons that are preferentially lost in human LHON.ConclusionsThese results in a pre-clinical mouse model of LHON suggest that mitochondrially-targeted AAV gene therapy, compared to allotopic AAV gene therapy, is more efficient in rescuing the LHON phenotype.
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Affiliation(s)
- Sindhu Velmurugan
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Tsung-Han Chou
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Jeremy D. Eastwood
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Vittorio Porciatti,
| | - Yuan Liu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - William W. Hauswirth
- Department of Ophthalmology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - John Guy
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Hong Yu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
- Hong Yu,
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5
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Millington-Ward S, Chadderton N, Finnegan LK, Post IJM, Carrigan M, Nixon R, Humphries MM, Humphries P, Kenna PF, Palfi A, Farrar GJ. RPE-Directed Gene Therapy Improves Mitochondrial Function in Murine Dry AMD Models. Int J Mol Sci 2023; 24:ijms24043847. [PMID: 36835257 PMCID: PMC9968062 DOI: 10.3390/ijms24043847] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/03/2023] [Accepted: 02/04/2023] [Indexed: 02/17/2023] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness in the aged population. However, to date there is no effective treatment for the dry form of the disease, representing 85-90% of cases. AMD is an immensely complex disease which affects, amongst others, both retinal pigment epithelium (RPE) and photoreceptor cells and leads to the progressive loss of central vision. Mitochondrial dysfunction in both RPE and photoreceptor cells is emerging as a key player in the disease. There are indications that during disease progression, the RPE is first impaired and RPE dysfunction in turn leads to subsequent photoreceptor cell degeneration; however, the exact sequence of events has not as yet been fully determined. We recently showed that AAV delivery of an optimised NADH-ubiquinone oxidoreductase (NDI1) gene, a nuclear-encoded complex 1 equivalent from S. cerevisiae, expressed from a general promoter, provided robust benefit in a variety of murine and cellular models of dry AMD; this was the first study employing a gene therapy to directly boost mitochondrial function, providing functional benefit in vivo. However, use of a restricted RPE-specific promoter to drive expression of the gene therapy enables exploration of the optimal target retinal cell type for dry AMD therapies. Furthermore, such restricted transgene expression could reduce potential off-target effects, possibly improving the safety profile of the therapy. Therefore, in the current study, we interrogate whether expression of the gene therapy from the RPE-specific promoter, Vitelliform macular dystrophy 2 (VMD2), might be sufficient to rescue dry AMD models.
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Affiliation(s)
- Sophia Millington-Ward
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
- Correspondence:
| | - Naomi Chadderton
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Laura K. Finnegan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Iris J. M. Post
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Matthew Carrigan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Rachel Nixon
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Marian M. Humphries
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Pete Humphries
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - Paul F. Kenna
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
- The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51 Dublin, Ireland
| | - Arpad Palfi
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
| | - G. Jane Farrar
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, D02 VF25 Dublin, Ireland
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6
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Optimisation of AAV-NDI1 Significantly Enhances Its Therapeutic Value for Correcting Retinal Mitochondrial Dysfunction. Pharmaceutics 2023; 15:pharmaceutics15020322. [PMID: 36839646 PMCID: PMC9960502 DOI: 10.3390/pharmaceutics15020322] [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: 11/11/2022] [Revised: 12/27/2022] [Accepted: 01/07/2023] [Indexed: 01/20/2023] Open
Abstract
AAV gene therapy for ocular disease has become a reality with the market authorisation of LuxturnaTM for RPE65-linked inherited retinal degenerations and many AAV gene therapies currently undergoing phase III clinical trials. Many ocular disorders have a mitochondrial involvement from primary mitochondrial disorders such as Leber hereditary optic neuropathy (LHON), predominantly due to mutations in genes encoding subunits of complex I, to Mendelian and multifactorial ocular conditions such as dominant optic atrophy, glaucoma and age-related macular degeneration. In this study, we have optimised the nuclear yeast gene, NADH-quinone oxidoreductase (NDI1), which encodes a single subunit complex I equivalent, creating a candidate gene therapy to improve mitochondrial function, independent of the genetic mutation driving disease. Optimisation of NDI1 (ophNdi1) substantially increased expression in vivo, protected RGCs and increased visual function, as assessed by optokinetic and photonegative response, in a rotenone-induced murine model. In addition, ophNdi1 increased cellular oxidative phosphorylation and ATP production and protected cells from rotenone insult to a significantly greater extent than wild type NDI1. Significantly, ophNdi1 treatment of complex I deficient patient-derived fibroblasts increased oxygen consumption and ATP production rates, demonstrating the potential of ophNdi1 as a candidate therapy for ocular disorders where mitochondrial deficits comprise an important feature.
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7
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Saidia AR, Ruel J, Bahloul A, Chaix B, Venail F, Wang J. Current Advances in Gene Therapies of Genetic Auditory Neuropathy Spectrum Disorder. J Clin Med 2023; 12:jcm12030738. [PMID: 36769387 PMCID: PMC9918155 DOI: 10.3390/jcm12030738] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023] Open
Abstract
Auditory neuropathy spectrum disorder (ANSD) refers to a range of hearing impairments characterized by an impaired transmission of sound from the cochlea to the brain. This defect can be due to a lesion or defect in the inner hair cell (IHC), IHC ribbon synapse (e.g., pre-synaptic release of glutamate), postsynaptic terminals of the spiral ganglion neurons, or demyelination and axonal loss within the auditory nerve. To date, the only clinical treatment options for ANSD are hearing aids and cochlear implantation. However, despite the advances in hearing-aid and cochlear-implant technologies, the quality of perceived sound still cannot match that of the normal ear. Recent advanced genetic diagnostics and clinical audiology made it possible to identify the precise site of a lesion and to characterize the specific disease mechanisms of ANSD, thus bringing renewed hope to the treatment or prevention of auditory neurodegeneration. Moreover, genetic routes involving the replacement or corrective editing of mutant sequences or defected genes to repair damaged cells for the future restoration of hearing in deaf people are showing promise. In this review, we provide an update on recent discoveries in the molecular pathophysiology of genetic lesions, auditory synaptopathy and neuropathy, and gene-therapy research towards hearing restoration in rodent models and in clinical trials.
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Affiliation(s)
- Anissa Rym Saidia
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34295 Montpellier, France
| | - Jérôme Ruel
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34295 Montpellier, France
- Cognitive Neuroscience Laboratory, Aix-Marseille University, CNRS, UMR 7291, 13331 Marseille, France
| | - Amel Bahloul
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34295 Montpellier, France
| | - Benjamin Chaix
- Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, 34295 Montpellier, France
| | - Frédéric Venail
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34295 Montpellier, France
- Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, 34295 Montpellier, France
| | - Jing Wang
- Institute for Neurosciences of Montpellier (INM), University Montpellier, INSERM, 34295 Montpellier, France
- Department of ENT and Head and Neck Surgery, University Hospital of Montpellier, 34295 Montpellier, France
- Correspondence: ; Tel.: +33-499-63-60-48
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Soldatov VO, Kubekina MV, Skorkina MY, Belykh AE, Egorova TV, Korokin MV, Pokrovskiy MV, Deykin AV, Angelova PR. Current advances in gene therapy of mitochondrial diseases. J Transl Med 2022; 20:562. [PMID: 36471396 PMCID: PMC9724384 DOI: 10.1186/s12967-022-03685-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/04/2022] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial diseases (MD) are a heterogeneous group of multisystem disorders involving metabolic errors. MD are characterized by extremely heterogeneous symptoms, ranging from organ-specific to multisystem dysfunction with different clinical courses. Most primary MD are autosomal recessive but maternal inheritance (from mtDNA), autosomal dominant, and X-linked inheritance is also known. Mitochondria are unique energy-generating cellular organelles designed to survive and contain their own unique genetic coding material, a circular mtDNA fragment of approximately 16,000 base pairs. The mitochondrial genetic system incorporates closely interacting bi-genomic factors encoded by the nuclear and mitochondrial genomes. Understanding the dynamics of mitochondrial genetics supporting mitochondrial biogenesis is especially important for the development of strategies for the treatment of rare and difficult-to-diagnose diseases. Gene therapy is one of the methods for correcting mitochondrial disorders.
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Affiliation(s)
- Vladislav O. Soldatov
- grid.4886.20000 0001 2192 9124Core Facility Centre, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia ,grid.445984.00000 0001 2224 0652Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia ,grid.445984.00000 0001 2224 0652Laboratory of Genome Editing for Biomedicine and Animal Health, Belgorod State National Research University, Belgorod, Russia ,grid.465470.4Laboratory of Biophysics of Cell Membranes under Critical State, V.A. Negovsky Scientific Research Institute of General Reanimatology, Russian Academy of Sciences, Moscow, Russia
| | - Marina V. Kubekina
- grid.4886.20000 0001 2192 9124Core Facility Centre, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Marina Yu. Skorkina
- grid.445984.00000 0001 2224 0652Department of Biochemistry, Belgorod State National Research University, Belgorod, Russia ,grid.445984.00000 0001 2224 0652Laboratory of Genome Editing for Biomedicine and Animal Health, Belgorod State National Research University, Belgorod, Russia
| | - Andrei E. Belykh
- grid.419305.a0000 0001 1943 2944Dioscuri Centre for Metabolic Diseases, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Tatiana V. Egorova
- grid.4886.20000 0001 2192 9124Laboratory of Modeling and Gene Therapy of Hereditary Diseases, Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail V. Korokin
- grid.445984.00000 0001 2224 0652Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia
| | - Mikhail V. Pokrovskiy
- grid.445984.00000 0001 2224 0652Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia
| | - Alexey V. Deykin
- grid.445984.00000 0001 2224 0652Department of Pharmacology and Clinical Pharmacology, Belgorod State National Research University, Belgorod, Russia ,grid.445984.00000 0001 2224 0652Laboratory of Genome Editing for Biomedicine and Animal Health, Belgorod State National Research University, Belgorod, Russia
| | - Plamena R. Angelova
- grid.83440.3b0000000121901201Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
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Chen BS, Yu-Wai-Man P, Newman NJ. Developments in the Treatment of Leber Hereditary Optic Neuropathy. Curr Neurol Neurosci Rep 2022; 22:881-892. [PMID: 36414808 PMCID: PMC9750907 DOI: 10.1007/s11910-022-01246-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2022] [Indexed: 11/24/2022]
Abstract
PURPOSEOF REVIEW To outline the current landscape of treatments for Leber hereditary optic neuropathy (LHON) along the therapeutic delivery pipeline, exploring the mechanisms of action and evidence for these therapeutic approaches. RECENT FINDINGS Treatments for LHON can be broadly classified as either mutation-specific or mutation-independent. Mutation-specific therapies aim to correct the underlying mutation through the use of a gene-editing platform or replace the faulty mitochondrial DNA-encoded protein by delivering the wild-type gene using a suitable vector. Recent gene therapy clinical trials assessing the efficacy of allotopically expressed MT-ND4 for the treatment of LHON due to the m.11778G > A mutation in MT-ND4 have shown positive results when treated within 12 months of symptom onset. Mutation-independent therapies can have various downstream targets that aim to improve mitochondrial respiration, reduce mitochondrial stress, inhibit or delay retinal ganglion cell apoptosis, and/or promote retinal ganglion cell survival. Idebenone, a synthetic hydrosoluble analogue of co-enzyme Q10 (ubiquinone), is the only approved treatment for LHON. Mutation-independent approaches to gene therapy under pre-clinical investigation for other neurodegenerative disorders may have the potential to benefit patients with LHON. Although approved treatments are presently limited, innovations in gene therapy and editing are driving the expansion of the therapeutic delivery pipeline for LHON.
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Affiliation(s)
- Benson S Chen
- John Van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK.
- Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK.
| | - Patrick Yu-Wai-Man
- John Van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
- Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | - Nancy J Newman
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
- Department of Neurological Surgery, Emory University School of Medicine, Atlanta, GA, USA
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10
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Traitements médicaux dans la neuropathie optique héréditaire de Leber. J Fr Ophtalmol 2022; 45:S24-S31. [DOI: 10.1016/s0181-5512(22)00447-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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11
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Chen BS, Yu-Wai-Man P. From Bench to Bedside-Delivering Gene Therapy for Leber Hereditary Optic Neuropathy. Cold Spring Harb Perspect Med 2022; 12:a041282. [PMID: 35863905 PMCID: PMC9310952 DOI: 10.1101/cshperspect.a041282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Leber hereditary optic neuropathy (LHON) is a rare, maternally inherited mitochondrial disorder that presents with severe bilateral sequential vision loss, due to the selective degeneration of retinal ganglion cells (RGCs). Since the mitochondrial genetic basis for LHON was uncovered in 1988, considerable progress has been made in understanding the pathogenetic mechanisms driving RGC loss, which has enabled the development of therapeutic approaches aimed at mitigating the underlying mitochondrial dysfunction. In this review, we explore the genetics of LHON, from bench to bedside, focusing on the pathogenetic mechanisms and how these have informed the development of different gene therapy approaches, in particular the technique of allotopic expression with adeno-associated viral vectors. Finally, we provide an overview of the recent gene therapy clinical trials and consider the unanswered questions, challenges, and future prospects.
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Affiliation(s)
- Benson S Chen
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, United Kingdom
- Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge CB2 0QQ, United Kingdom
| | - Patrick Yu-Wai-Man
- John van Geest Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 0PY, United Kingdom
- Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge CB2 0QQ, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, United Kingdom
- Institute of Ophthalmology, University College London, London EC1V 9EL, United Kingdom
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12
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Palfi A, Chadderton N, Millington-Ward S, Post I, Humphries P, Kenna PF, Farrar GJ. AAV-PHP.eB transduces both the inner and outer retina with high efficacy in mice. Mol Ther Methods Clin Dev 2022; 25:236-249. [PMID: 35474956 PMCID: PMC9018541 DOI: 10.1016/j.omtm.2022.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/27/2022] [Indexed: 12/18/2022]
Abstract
Recombinant adeno-associated virus (AAV) vectors are one of the main gene delivery vehicles used in retinal gene therapy approaches; however, there is a need to further improve the efficacy, tropism, and safety of these vectors. In this study, using a CMV-EGFP expression cassette, we characterize the retinal utility of AAV-PHP.eB, a serotype recently developed by in vivo directed evolution, which can cross the blood-brain barrier and target neurons with high efficacy in mice. Systemic and intravitreal delivery of AAV-PHP.eB resulted in the high transduction efficacy of retinal ganglion and horizontal cells, with systemic delivery providing pan-retinal coverage of the mouse retina. Subretinal delivery transduced photoreceptors and retinal pigment epithelium cells robustly. EGFP expression (number of transduced cells and mRNA levels) were similar when the retinas were transduced systemically or intravitreally with AAV-PHP.eB or intravitreally with AAV2/2. Notably, in photoreceptors, EGFP fluorescence intensities and mRNA levels were 50–70 times higher, when subretinal injections with AAV-PHP.eB were compared to AAV2/8. Our results demonstrate the pan-retinal transduction of ganglion cells and extremely efficient transduction of photoreceptor and retinal pigment epithelium cells as the most valuable features of AAV-PHP.eB in the mouse retina.
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Affiliation(s)
- Arpad Palfi
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland
| | - Naomi Chadderton
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland
| | - Sophia Millington-Ward
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland
| | - Iris Post
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland
| | - Pete Humphries
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland
| | - Paul F Kenna
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland.,The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51, Dublin, Ireland
| | - G Jane Farrar
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, D02 VF25, Dublin, Ireland
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13
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Finnegan LK, Chadderton N, Kenna PF, Palfi A, Carty M, Bowie AG, Millington-Ward S, Farrar GJ. SARM1 Ablation Is Protective and Preserves Spatial Vision in an In Vivo Mouse Model of Retinal Ganglion Cell Degeneration. Int J Mol Sci 2022; 23:ijms23031606. [PMID: 35163535 PMCID: PMC8835928 DOI: 10.3390/ijms23031606] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
The challenge of developing gene therapies for genetic forms of blindness is heightened by the heterogeneity of these conditions. However, mechanistic commonalities indicate key pathways that may be targeted in a gene-independent approach. Mitochondrial dysfunction and axon degeneration are common features of many neurodegenerative conditions including retinal degenerations. Here we explore the neuroprotective effect afforded by the absence of sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1), a prodegenerative NADase, in a rotenone-induced mouse model of retinal ganglion cell loss and visual dysfunction. Sarm1 knockout mice retain visual function after rotenone insult, displaying preservation of photopic negative response following rotenone treatment in addition to significantly higher optokinetic response measurements than wild type mice following rotenone. Protection of spatial vision is sustained over time in both sexes and is accompanied by increased RGC survival and additionally preservation of axonal density in optic nerves of Sarm1−/− mice insulted with rotenone. Primary fibroblasts extracted from Sarm1−/− mice demonstrate an increased oxygen consumption rate relative to those from wild type mice, with significantly higher basal, maximal and spare respiratory capacity. Collectively, our data indicate that Sarm1 ablation increases mitochondrial bioenergetics and confers histological and functional protection in vivo in the mouse retina against mitochondrial dysfunction, a hallmark of many neurodegenerative conditions including a variety of ocular disorders.
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Affiliation(s)
- Laura K. Finnegan
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
- Correspondence:
| | - Naomi Chadderton
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
| | - Paul F. Kenna
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
- The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51 Dublin, Ireland
| | - Arpad Palfi
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
| | - Michael Carty
- Trinity Biomedical Sciences Institute, The School of Biochemistry and Immunology, Trinity College Dublin, D02 R590 Dublin, Ireland; (M.C.); (A.G.B.)
| | - Andrew G. Bowie
- Trinity Biomedical Sciences Institute, The School of Biochemistry and Immunology, Trinity College Dublin, D02 R590 Dublin, Ireland; (M.C.); (A.G.B.)
| | - Sophia Millington-Ward
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
| | - G. Jane Farrar
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
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14
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Wang Y, Hu LF, Cui PF, Qi LY, Xing L, Jiang HL. Pathologically Responsive Mitochondrial Gene Therapy in an Allotopic Expression-Independent Manner Cures Leber's Hereditary Optic Neuropathy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2103307. [PMID: 34431574 DOI: 10.1002/adma.202103307] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Leber's hereditary optic neuropathy (LHON) is a rare inherited blindness caused by mutations in the mitochondrial DNA (mtDNA). The disorder is untreatable and tricky, as the existing chemotherapeutic agent Idebenone alleviates symptoms rather than overcoming the underlying cause. Although some studies have made progress on allotopic expression for LHON, in situ mitochondrial gene therapy remains challenging, which may simplify delivery procedures to be a promising therapeutic for LHON. LHON becomes more difficult to manage in the changed mitochondrial microenvironment, including increasing reactive oxygen species (ROS) and decreasing mitochondrial membrane potential (MMP). Herein, a pathologically responsive mitochondrial gene delivery vector named [triphenylphosphine-terminated poly(sulfur-containing thioketal undecafluorohexylamine histamine) and Ide-terminated poly(sulfur-containing thioketal undecafluorohexylamine histamine)] (TISUH) is reported to facilitate commendable in situ mitochondrial gene therapy for LHON. TISUH directly targets diseased mitochondria via triphenylphosphine and fluorination addressing the decreasing MMP. In addition, TISUH can be disassembled by high mitochondrial ROS levels to release functional genes for enhancing gene transfection efficiency and fundamentally correcting genetic abnormalities. In both traditional and gene-mutation-induced LHON mouse models, TISUH-mediated gene therapy shows satisfactory curative effect through the sustained therapeutic protein expression in vivo. This work proposes a novel pathologically responsive in situ mitochondrial delivery platform and provides a promising approach for refractory LHON as well as other mtDNA mutated diseases treatments.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Li-Fan Hu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Peng-Fei Cui
- School of Pharmacy, Changzhou University, Changzhou, 213164, China
| | - Lian-Yu Qi
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Lei Xing
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
| | - Hu-Lin Jiang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Druggability of Biopharmaceuticals, China Pharmaceutical University, Nanjing, 210009, China
- Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
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15
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Hage R, Vignal-Clermont C. Leber Hereditary Optic Neuropathy: Review of Treatment and Management. Front Neurol 2021; 12:651639. [PMID: 34122299 PMCID: PMC8187781 DOI: 10.3389/fneur.2021.651639] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 04/06/2021] [Indexed: 01/16/2023] Open
Abstract
Leber hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease that specifically targets the retinal ganglion cells by reducing their ability to produce enough energy to sustain. The mutations of the mitochondrial DNA that cause LHON are silent until an unknown trigger causes bilateral central visual scotoma. After the onset of loss of vision, most patients experience progressive worsening within the following months. Few of them regain some vision after a period of ~1 year. Management of LHON patients has been focused on understanding the triggers of the disease and its pathophysiology to prevent the onset of visual loss in a carrier. Medical treatment is recommended once visual loss has started in at least one eye. Research evaluated drugs that are thought to be able to restore the mitochondrial electron transport chain of the retinal ganglion cells. Significant advances were made in evaluating free radical cell scavengers and gene therapy as potential treatments for LHON. Although encouraging the results of clinical trial have been mixed in stopping the worsening of visual loss. In patients with chronic disease of over 1 year, efficient treatment that restores vision is yet to be discovered. In this review, we summarize the management strategies for patients with LHON before, during, and after the loss of vision, explain the rationale and effectiveness of previous and current treatments, and report findings about emerging treatments.
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Affiliation(s)
- Rabih Hage
- Neuro-ophthalmology Department, Hôpital Fondation Rothschild, Paris, France
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16
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Maloney DM, Chadderton N, Millington-Ward S, Palfi A, Shortall C, O'Byrne JJ, Cassidy L, Keegan D, Humphries P, Kenna P, Farrar GJ. Optimized OPA1 Isoforms 1 and 7 Provide Therapeutic Benefit in Models of Mitochondrial Dysfunction. Front Neurosci 2020; 14:571479. [PMID: 33324145 PMCID: PMC7726421 DOI: 10.3389/fnins.2020.571479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/30/2020] [Indexed: 01/09/2023] Open
Abstract
Optic Atrophy 1 (OPA1) is a mitochondrially targeted GTPase that plays a pivotal role in mitochondrial health, with mutations causing severe mitochondrial dysfunction and typically associated with Dominant Optic Atrophy (DOA), a progressive blinding disease involving retinal ganglion cell loss and optic nerve damage. In the current study, we investigate the use of codon-optimized versions of OPA1 isoform 1 and 7 as potential therapeutic interventions in a range of in vitro and in vivo models of mitochondrial dysfunction. We demonstrate that both isoforms perform equally well in ameliorating mitochondrial dysfunction in OPA1 knockout mouse embryonic fibroblast cells but that OPA1 expression levels require tight regulation for optimal benefit. Of note, we demonstrate for the first time that both OPA1 isoform 1 and 7 can be used independently to protect spatial visual function in a murine model of retinal ganglion cell degeneration caused by mitochondrial dysfunction, as well as providing benefit to mitochondrial bioenergetics in DOA patient derived fibroblast cells. These results highlight the potential value of OPA1-based gene therapy interventions.
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Affiliation(s)
- Daniel M Maloney
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Naomi Chadderton
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | | | - Arpad Palfi
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Ciara Shortall
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | - James J O'Byrne
- National Centre for Inherited Metabolic Disorders, The Mater Misericordiae University Hospital, Dublin, Ireland.,Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, Dublin, Ireland
| | - Lorraine Cassidy
- The Research Foundation, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - David Keegan
- Clinical Genetics Centre for Ophthalmology, The Mater Misericordiae University Hospital, Dublin, Ireland
| | - Peter Humphries
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Paul Kenna
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland.,The Research Foundation, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Gwyneth Jane Farrar
- The School of Genetics & Microbiology, Trinity College Dublin, Dublin, Ireland
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17
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Bottani E, Lamperti C, Prigione A, Tiranti V, Persico N, Brunetti D. Therapeutic Approaches to Treat Mitochondrial Diseases: "One-Size-Fits-All" and "Precision Medicine" Strategies. Pharmaceutics 2020; 12:E1083. [PMID: 33187380 PMCID: PMC7696526 DOI: 10.3390/pharmaceutics12111083] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 12/11/2022] Open
Abstract
Primary mitochondrial diseases (PMD) refer to a group of severe, often inherited genetic conditions due to mutations in the mitochondrial genome or in the nuclear genes encoding for proteins involved in oxidative phosphorylation (OXPHOS). The mutations hamper the last step of aerobic metabolism, affecting the primary source of cellular ATP synthesis. Mitochondrial diseases are characterized by extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. The limited information of the natural history, the limitations of currently available preclinical models, coupled with the large variability of phenotypical presentations of PMD patients, have strongly penalized the development of effective therapies. However, new therapeutic strategies have been emerging, often with promising preclinical and clinical results. Here we review the state of the art on experimental treatments for mitochondrial diseases, presenting "one-size-fits-all" approaches and precision medicine strategies. Finally, we propose novel perspective therapeutic plans, either based on preclinical studies or currently used for other genetic or metabolic diseases that could be transferred to PMD.
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Affiliation(s)
- Emanuela Bottani
- Department of Diagnostics and Public Health, Section of Pharmacology, University of Verona, 37134 Verona, Italy
| | - Costanza Lamperti
- Medical Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy; (C.L.); (V.T.)
| | - Alessandro Prigione
- Department of General Pediatrics, Neonatology, and Pediatric Cardiology, University Clinic Düsseldorf (UKD), Heinrich Heine University (HHU), 40225 Dusseldorf, Germany;
| | - Valeria Tiranti
- Medical Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy; (C.L.); (V.T.)
| | - Nicola Persico
- Department of Clinical Science and Community Health, University of Milan, 20122 Milan, Italy;
- Fetal Medicine and Surgery Service, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Dario Brunetti
- Medical Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy; (C.L.); (V.T.)
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
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18
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Millington-Ward S, Chadderton N, Berkeley M, Finnegan LK, Hanlon KS, Carrigan M, Humphries P, Kenna PF, Palfi A, Farrar GJ. Novel 199 base pair NEFH promoter drives expression in retinal ganglion cells. Sci Rep 2020; 10:16515. [PMID: 33020509 PMCID: PMC7536420 DOI: 10.1038/s41598-020-73257-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 09/08/2020] [Indexed: 01/13/2023] Open
Abstract
Retinal ganglion cells (RGCs) are known to be involved in several ocular disorders, including glaucoma and Leber hereditary optic neuropathy (LHON), and hence represent target cells for gene therapies directed towards these diseases. Restricting gene therapeutics to the target cell type in many situations may be preferable compared to ubiquitous transgene expression, stimulating researchers to identify RGC-specific promoters, particularly promoter sequences that may also be appropriate in size to fit readily into recombinant adeno associated viral (AAV) vectors, the vector of choice for many ocular gene therapies. In the current study we analysed EGFP expression driven by various sequences of the putative human NEFH promoter in order to define sequences required for preferential expression in RGCs. EGFP expression profiles from four different potential NEFH promoter constructs were compared in vivo in mice using retinal histology and mRNA expression analysis. Notably, two efficient promoter sequences, one comprising just 199 bp, are presented in the study.
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Affiliation(s)
| | - Naomi Chadderton
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Megan Berkeley
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Laura K Finnegan
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Killian S Hanlon
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Matthew Carrigan
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Peter Humphries
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Paul F Kenna
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland.,The Research Foundation, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - Arpad Palfi
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - G Jane Farrar
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
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19
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Palfi A, Yesmambetov A, Millington-Ward S, Shortall C, Humphries P, Kenna PF, Chadderton N, Farrar GJ. AAV-Delivered Tulp1 Supplementation Therapy Targeting Photoreceptors Provides Minimal Benefit in Tulp1-/- Retinas. Front Neurosci 2020; 14:891. [PMID: 32973439 PMCID: PMC7482550 DOI: 10.3389/fnins.2020.00891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/30/2020] [Indexed: 12/23/2022] Open
Abstract
With marketing approval of the first ocular gene therapy, and other gene therapies in clinical trial, treatments for inherited retinal degenerations (IRDs) have become a reality. Biallelic mutations in the tubby like protein 1 gene (TULP1) are causative of IRDs in humans; a mouse knock-out model (Tulp1−/−) is characterized by a similar disease phenotype. We developed a Tulp1 supplementation therapy for Tulp1−/− mice. Utilizing subretinal AAV2/5 delivery at postnatal day (p)2–3 and rhodopsin-kinase promoter (GRK1P) we targeted Tulp1 to photoreceptor cells exploring three doses, 2.2E9, 3.7E8, and 1.2E8 vgs. Tulp1 mRNA and TULP1 protein were assessed by RT-qPCR, western blot and immunocytochemistry, and visual function by electroretinography. Our results indicate that TULP1 was expressed in photoreceptors; achieved levels of Tulp1 mRNA and protein were similar to wild type levels at p20. However, the thickness of the outer nuclear layer (ONL) did not improve in treated Tulp1−/− mice. There was a small and transient electroretinography benefit in the treated retinas at 4 weeks of age (not observed by 6 weeks) when using 3.7E8 vg dose. Dark-adapted mixed rod and cone a- and b-wave amplitudes were 24.3 ± 13.5 μV and 52.2 ± 31.7 μV in treated Tulp1−/− mice, which were significantly different (p < 0.001, t-test), from those detected in untreated eyes (7.1 ± 7.0 μV and 9.4 ± 15.1 μV, respectively). Our results indicate that Tulp1 supplementation in photoreceptors may not be sufficient to provide robust benefit in Tulp1−/− mice. As such, further studies are required to fine tune the Tulp1 supplementation therapy, which, in principle, should rescue the Tulp1−/− phenotype.
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Affiliation(s)
- Arpad Palfi
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Adlet Yesmambetov
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Sophia Millington-Ward
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Ciara Shortall
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Pete Humphries
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Paul F Kenna
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - Naomi Chadderton
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | - G Jane Farrar
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
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20
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Tay LS, Palmer N, Panwala R, Chew WL, Mali P. Translating CRISPR-Cas Therapeutics: Approaches and Challenges. CRISPR J 2020; 3:253-275. [PMID: 32833535 PMCID: PMC7469700 DOI: 10.1089/crispr.2020.0025] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
CRISPR-Cas clinical trials have begun, offering a first glimpse at how DNA and RNA targeting could enable therapies for many genetic and epigenetic human diseases. The speedy progress of CRISPR-Cas from discovery and adoption to clinical use is built on decades of traditional gene therapy research and belies the multiple challenges that could derail the successful translation of these new modalities. Here, we review how CRISPR-Cas therapeutics are translated from technological systems to therapeutic modalities, paying particular attention to the therapeutic cascade from cargo to delivery vector, manufacturing, administration, pipelines, safety, and therapeutic target profiles. We also explore potential solutions to some of the obstacles facing successful CRISPR-Cas translation. We hope to illuminate how CRISPR-Cas is brought from the academic bench toward use in the clinic.
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Affiliation(s)
- Lavina Sierra Tay
- Laboratory of Synthetic Biology and Genome Editing Therapeutics, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Nathan Palmer
- Division of Biological Sciences, University of California San Diego, La Jolla, California, USA
| | - Rebecca Panwala
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
| | - Wei Leong Chew
- Laboratory of Synthetic Biology and Genome Editing Therapeutics, Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Prashant Mali
- Department of Bioengineering, University of California San Diego, La Jolla, California, USA
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21
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Sasaoka M, Ota T, Kageyama M. Rotenone-induced inner retinal degeneration via presynaptic activation of voltage-dependent sodium and L-type calcium channels in rats. Sci Rep 2020; 10:969. [PMID: 31969611 PMCID: PMC6976703 DOI: 10.1038/s41598-020-57638-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/31/2019] [Indexed: 01/11/2023] Open
Abstract
Rotenone, a mitochondrial complex I inhibitor, causes retinal degeneration via unknown mechanisms. To elucidate the molecular mechanisms of its action, we further characterized a rat model of rotenone-induced retinal degeneration. Intravitreal injection of rotenone (2 nmol/eye) damaged mainly the inner retinal layers, including cell loss in the ganglion cell and inner nuclear layers, which were very similar to those induced by 10 nmol/eye N-methyl-D-aspartate (NMDA). These morphological changes were accompanied by the reduced b-wave amplitude of electroretinogram, and increased immunostaining of 2,4-dinitrophenyl, an oxidative stress marker. Rotenone also downregulated expression of neurofilament light-chain gene (Nfl) as a retinal ganglion cell (RGC) marker. This effect was prevented by simultaneous injection of rotenone with antioxidants or NMDA receptor antagonists. More importantly, voltage-dependent sodium and L-type calcium channel blockers and intracellular calcium signaling modulators remarkably suppressed rotenone-induced Nfl downregulation, whereas none of these agents modified NMDA-induced Nfl downregulation. These results suggest that rotenone-induced inner retinal degeneration stems from indirect postsynaptic NMDA stimulation that is triggered by oxidative stress-mediated presynaptic intracellular calcium signaling via activation of voltage-dependent sodium and L-type calcium channels.
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Affiliation(s)
- Masaaki Sasaoka
- Global Alliances and External Research, Santen Pharmaceutical Co., Ltd., Ikoma-shi, Nara, 630-0101, Japan
| | - Takashi Ota
- Global Alliances and External Research, Santen Pharmaceutical Co., Ltd., Ikoma-shi, Nara, 630-0101, Japan
| | - Masaaki Kageyama
- Global Alliances and External Research, Santen Pharmaceutical Co., Ltd., Ikoma-shi, Nara, 630-0101, Japan.
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22
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Arabidopsis thaliana alternative dehydrogenases: a potential therapy for mitochondrial complex I deficiency? Perspectives and pitfalls. Orphanet J Rare Dis 2019; 14:236. [PMID: 31665043 PMCID: PMC6821020 DOI: 10.1186/s13023-019-1185-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Complex I (CI or NADH:ubiquinone oxidoreductase) deficiency is the most frequent cause of mitochondrial respiratory chain defect. Successful attempts to rescue CI function by introducing an exogenous NADH dehydrogenase, such as the NDI1 from Saccharomyces cerevisiae (ScNDI1), have been reported although with drawbacks related to competition with CI. In contrast to ScNDI1, which is permanently active in yeast naturally devoid of CI, plant alternative NADH dehydrogenases (NDH-2) support the oxidation of NADH only when the CI is metabolically inactive and conceivably when the concentration of matrix NADH exceeds a certain threshold. We therefore explored the feasibility of CI rescue by NDH-2 from Arabidopsis thaliana (At) in human CI defective fibroblasts. RESULTS We showed that, other than ScNDI1, two different NDH-2 (AtNDA2 and AtNDB4) targeted to the mitochondria were able to rescue CI deficiency and decrease oxidative stress as indicated by a normalization of SOD activity in human CI-defective fibroblasts. We further demonstrated that when expressed in human control fibroblasts, AtNDA2 shows an affinity for NADH oxidation similar to that of CI, thus competing with CI for the oxidation of NADH as opposed to our initial hypothesis. This competition reduced the amount of ATP produced per oxygen atom reduced to water by half in control cells. CONCLUSIONS In conclusion, despite their promising potential to rescue CI defects, due to a possible competition with remaining CI activity, plant NDH-2 should be regarded with caution as potential therapeutic tools for human mitochondrial diseases.
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23
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Liu W, Li X, Chen X, Zhang J, Luo L, Hu Q, Zhou J, Yan J, Lin S, Ye J. JIP1 Deficiency Protects Retinal Ganglion Cells From Apoptosis in a Rotenone-Induced Injury Model. Front Cell Dev Biol 2019; 7:225. [PMID: 31681759 PMCID: PMC6804425 DOI: 10.3389/fcell.2019.00225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/24/2019] [Indexed: 11/13/2022] Open
Abstract
Retinal ganglion cells (RGCs) undergo apoptosis after injury. c-Jun N-terminal kinase (JNK)-interacting protein 1 (JIP1) is a scaffold protein that is relevant to JNK activation and a key molecule known to regulate neuronal apoptosis. However, the specific role of JIP1 in the apoptosis of RGCs is currently undefined. Here, we used JIP1 gene knockout (KO) mice to investigate the importance of JIP1-JNK signaling in the apoptosis of RGCs in a rotenone-induced injury model. In adult JIP1 KO mice, the number and electrophysiological functions of RGCs were not different from those of wild-type (WT) mice. Ablation of JIP1 attenuated the activation of JNK and the cleavage of caspase-3 in the retina after rotenone injury and contributed to a lower number of TUNEL-positive RGCs, a greater percentage of surviving RGCs, and a significant reduction in the electrophysiological functional loss of RGCs when compared to those in WT controls. We also found that JIP1 was located in the neurites of primary RGCs, but accumulated in soma in response to rotenone treatment. Moreover, the number of TUNEL-positive RGCs, the level of activation of JNK and the rate of cleavage of caspase-3 were reduced in primary JIP1-deficient RGCs after rotenone injury than in WT controls. Together, our results demonstrate that the JIP1-mediated activation of JNK contributes to the apoptosis of RGCs in a rotenone-induced injury model in vitro and in vivo, suggesting that JIP1 may be a potential therapeutic target for RGC degeneration.
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Affiliation(s)
- Wenyi Liu
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Xue Li
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Xi Chen
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Jieqiong Zhang
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Linlin Luo
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Qiumei Hu
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Jiaxing Zhou
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Jun Yan
- Department 1, Research Institute of Surgery & Daping Hospital, Army Medical University, Chongqing, China
| | - Sen Lin
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
| | - Jian Ye
- Department of Ophthalmology, Daping Hospital, Army Medical Center of PLA, Army Medical University, Chongqing, China
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24
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Indrieri A, Carrella S, Romano A, Spaziano A, Marrocco E, Fernandez‐Vizarra E, Barbato S, Pizzo M, Ezhova Y, Golia FM, Ciampi L, Tammaro R, Henao‐Mejia J, Williams A, Flavell RA, De Leonibus E, Zeviani M, Surace EM, Banfi S, Franco B. miR-181a/b downregulation exerts a protective action on mitochondrial disease models. EMBO Mol Med 2019; 11:emmm.201708734. [PMID: 30979712 PMCID: PMC6505685 DOI: 10.15252/emmm.201708734] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mitochondrial diseases (MDs) are a heterogeneous group of devastating and often fatal disorders due to defective oxidative phosphorylation. Despite the recent advances in mitochondrial medicine, effective therapies are still not available for these conditions. Here, we demonstrate that the microRNAs miR-181a and miR-181b (miR-181a/b) regulate key genes involved in mitochondrial biogenesis and function and that downregulation of these miRNAs enhances mitochondrial turnover in the retina through the coordinated activation of mitochondrial biogenesis and mitophagy. We thus tested the effect of miR-181a/b inactivation in different animal models of MDs, such as microphthalmia with linear skin lesions and Leber's hereditary optic neuropathy. We found that miR-181a/b downregulation strongly protects retinal neurons from cell death and significantly ameliorates the disease phenotype in all tested models. Altogether, our results demonstrate that miR-181a/b regulate mitochondrial homeostasis and that these miRNAs may be effective gene-independent therapeutic targets for MDs characterized by neuronal degeneration.
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Affiliation(s)
- Alessia Indrieri
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly,Medical GeneticsDepartment of Translational Medical ScienceUniversity of Naples “Federico II”NaplesItaly
| | - Sabrina Carrella
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly,Medical GeneticsDepartment of Precision MedicineUniversity of Campania “L. Vanvitelli”Caserta CEItaly
| | - Alessia Romano
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Elena Marrocco
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Sara Barbato
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Yulia Ezhova
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | | | - Ludovica Ciampi
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Roberta Tammaro
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly
| | - Jorge Henao‐Mejia
- Department of Pathology and Laboratory MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA,Institute for ImmunologyPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Adam Williams
- The Jackson Laboratory for Genomic MedicineFarmingtonCTUSA,Department of Genetics and Genomic SciencesUniversity of Connecticut Health CenterFarmingtonCTUSA
| | - Richard A Flavell
- Department of ImmunobiologyYale University School of MedicineNew HavenCTUSA,Howard Hughes Medical InstituteChevy ChaseMDUSA
| | - Elvira De Leonibus
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly,Institute of Cellular Biology and Neurobiology “ABT”CNRRomaItaly
| | - Massimo Zeviani
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
| | - Enrico M Surace
- Telethon Institute of Genetics and Medicine (TIGEM)PozzuoliItaly,Medical GeneticsDepartment of Translational Medical ScienceUniversity of Naples “Federico II”NaplesItaly,Present address:
Medical GeneticsDepartment of Translational Medical ScienceUniversity of Naples “Federico II”NaplesItaly
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy .,Medical Genetics, Department of Precision Medicine, University of Campania "L. Vanvitelli", Caserta CE, Italy
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy .,Medical Genetics, Department of Translational Medical Science, University of Naples "Federico II", Naples, Italy
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25
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Bian WP, Chen YL, Luo JJ, Wang C, Xie SL, Pei DS. Knock-In Strategy for Editing Human and Zebrafish Mitochondrial DNA Using Mito-CRISPR/Cas9 System. ACS Synth Biol 2019; 8:621-632. [PMID: 30955321 DOI: 10.1021/acssynbio.8b00411] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The mitochondria DNA (mtDNA) editing tool, zinc finger nucleases (ZFNs), transcription activator-like effector nuclease (TALENs), and clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/Cas9) system, is a promising approach for the treatment of mtDNA diseases by eliminating mutant mitochondrial genomes. However, there have been no reports of repairing the mutant mtDNA with homologous recombination strategy to date. Here, we show a mito-CRISPR/Cas9 system that mito-Cas9 protein can specifically target mtDNA and reduce mtDNA copy number in both human cells and zebrafish. An exogenous single-stranded DNA with short homologous arm was knocked into the targeting loci accurately, and this mutagenesis could be steadily transmitted to F1 generation of zebrafish. Moreover, we found some major factors involved in nuclear DNA repair were upregulated significantly by the mito-CRISPR/Cas9 system. Taken together, our data suggested that the mito-CRISPR/Cas9 system could be a useful method to edit mtDNA by knock-in strategy, providing a potential therapy for the treatment of inherited mitochondrial diseases.
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Affiliation(s)
- Wan-Ping Bian
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Yan-Ling Chen
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Juan-Juan Luo
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Chao Wang
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Shao-Lin Xie
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - De-Sheng Pei
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
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26
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Differential Effects of Yeast NADH Dehydrogenase (Ndi1) Expression on Mitochondrial Function and Inclusion Formation in a Cell Culture Model of Sporadic Parkinson's Disease. Biomolecules 2019; 9:biom9040119. [PMID: 30934776 PMCID: PMC6523508 DOI: 10.3390/biom9040119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/14/2019] [Accepted: 03/16/2019] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that exhibits aberrant protein aggregation and mitochondrial dysfunction. Ndi1, the yeast mitochondrial NADH dehydrogenase (complex I) enzyme, is a single subunit, internal matrix-facing protein. Previous studies have shown that Ndi1 expression leads to improved mitochondrial function in models of complex I-mediated mitochondrial dysfunction. The trans-mitochondrial cybrid cell model of PD was created by fusing mitochondrial DNA-depleted SH-SY5Y cells with platelets from a sporadic PD patient. PD cybrid cells reproduce the mitochondrial dysfunction observed in a patient's brain and periphery and form intracellular, cybrid Lewy bodies comparable to Lewy bodies in PD brain. To improve mitochondrial function and alter the formation of protein aggregates, Ndi1 was expressed in PD cybrid cells and parent SH-SY5Y cells. We observed a dramatic increase in mitochondrial respiration, increased mitochondrial gene expression, and increased PGC-1α gene expression in PD cybrid cells expressing Ndi1. Total cellular aggregated protein content was decreased but Ndi1 expression was insufficient to prevent cybrid Lewy body formation. Ndi1 expression leads to improved mitochondrial function and biogenesis signaling, both processes that could improve neuron survival during disease. However, other aspects of PD pathology such as cybrid Lewy body formation were not reduced. Consequently, resolution of mitochondrial dysfunction alone may not be sufficient to overcome other aspects of PD-related cellular pathology.
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27
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Zaninello M, Scorrano L. Rapidly purified ganglion cells from neonatal mouse retinas allow studies of mitochondrial morphology and autophagy. Pharmacol Res 2018; 138:16-24. [PMID: 30077733 DOI: 10.1016/j.phrs.2018.07.024] [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] [Received: 05/08/2018] [Revised: 07/27/2018] [Accepted: 07/29/2018] [Indexed: 01/09/2023]
Abstract
Retinal explants and mixed primary cultures are currently used to investigate retinal ganglion cells (RGCs) pathophysiology and pharmacology, but information on yield, quality and quantity of contaminant cells for the available RGCs enrichment techniques is lacking. Here we compare two methods of mouse primary RGCs purification and show that mitochondrial and autophagy parameters can be measured in rapidly purified RGCs. RGCs were purified from P0 mouse eyes using two methods based on the surface antigen Thy1. In a two-step immunopanning purification, a subtraction plate bound macrophage antiserum removed contaminant macrophages and endothelial cells; unbound RGCs were then affinity selected using a plate-bound antiThy1 antibody. In an immunopanning-magnetic separation, macrophage-antiserum bound cells were first subtracted and then RGCs were positively selected using an antiThy1 antibody bound to a magnetic column. The two-steps immunopanning yielded low amounts of 90% pure RGCs, whereas RGCs represented 30% of the 6-fold more cells collected by immunopanning-magnetic separation. RGCs purified with both methods could be microelectroporated to image expressed mitochondria and autophagosomes fluorescent probes and to show that expression of pathogenic Optic atrophy 1 mutants causes mitochondrial fragmentation. Thus, these two methods purify primary mouse RGCs amenable to studies of cell morphology, mitochondrial biology and autophagy.
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Affiliation(s)
- Marta Zaninello
- Venetian Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy; Department of Biology, University of Padova, Via U. Bassi 58B, 35121 Padova, Italy
| | - Luca Scorrano
- Venetian Institute of Molecular Medicine, Via Orus 2, 35129 Padova, Italy; Department of Biology, University of Padova, Via U. Bassi 58B, 35121 Padova, Italy.
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28
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Aravintha Siva M, Mahalakshmi R, Bhakta-Guha D, Guha G. Gene therapy for the mitochondrial genome: Purging mutations, pacifying ailments. Mitochondrion 2018; 46:195-208. [PMID: 29890303 DOI: 10.1016/j.mito.2018.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
In the recent years, the reported cases of mitochondrial disorders have reached a colossal number. These disorders spawn a sundry of pathological conditions, which lead to pernicious symptoms and even fatality. Due to the unpredictable etiologies, mitochondrial diseases are putatively referred to as "mystondria" (mysterious diseases of mitochondria). Although present-day research has greatly improved our understanding of mitochondrial disorders, effective therapeutic interventions are still at the precursory stage. The conundrum becomes further complicated because these pathologies might occur due to either mitochondrial DNA (mtDNA) mutations or due to mutations in the nuclear DNA (nDNA), or both. While correcting nDNA mutations by using gene therapy (replacement of defective genes by delivering wild-type (WT) ones into the host cell, or silencing a dominant mutant allele that is pathogenic) has emerged as a promising strategy to address some mitochondrial diseases, the complications in correcting the defects of mtDNA in order to renovate mitochondrial functions have remained a steep challenge. In this review, we focus specifically on the selective gene therapy strategies that have demonstrated prospects in targeting the pathological mutations in the mitochondrial genome, thereby treating mitochondrial ailments.
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Affiliation(s)
- M Aravintha Siva
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - R Mahalakshmi
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | - Dipita Bhakta-Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
| | - Gunjan Guha
- Cellular Dyshomeostasis Laboratory (CDHL), School of Chemical and Bio Technology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India.
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29
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Farrar GJ, Carrigan M, Dockery A, Millington-Ward S, Palfi A, Chadderton N, Humphries M, Kiang AS, Kenna PF, Humphries P. Toward an elucidation of the molecular genetics of inherited retinal degenerations. Hum Mol Genet 2017; 26:R2-R11. [PMID: 28510639 PMCID: PMC5886474 DOI: 10.1093/hmg/ddx185] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 05/08/2017] [Indexed: 02/06/2023] Open
Abstract
While individually classed as rare diseases, hereditary retinal degenerations (IRDs) are the major cause of registered visual handicap in the developed world. Given their hereditary nature, some degree of intergenic heterogeneity was expected, with genes segregating in autosomal dominant, recessive, X-linked recessive, and more rarely in digenic or mitochondrial modes. Today, it is recognized that IRDs, as a group, represent one of the most genetically diverse of hereditary conditions - at least 260 genes having been implicated, with 70 genes identified in the most common IRD, retinitis pigmentosa (RP). However, targeted sequencing studies of exons from known IRD genes have resulted in the identification of candidate mutations in only approximately 60% of IRD cases. Given recent advances in the development of gene-based medicines, characterization of IRD patient cohorts for known IRD genes and elucidation of the molecular pathologies of disease in those remaining unresolved cases has become an endeavor of the highest priority. Here, we provide an outline of progress in this area.
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Affiliation(s)
- G Jane Farrar
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Matthew Carrigan
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Adrian Dockery
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Sophia Millington-Ward
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Arpad Palfi
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Naomi Chadderton
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Marian Humphries
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Anna Sophia Kiang
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
| | - Paul F Kenna
- Research Foundation, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - Pete Humphries
- Institute of Genetics, School of Genetics and Microbiology, University of Dublin, Trinity College, Dublin 2, Ireland
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30
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Hanlon KS, Chadderton N, Palfi A, Blanco Fernandez A, Humphries P, Kenna PF, Millington-Ward S, Farrar GJ. A Novel Retinal Ganglion Cell Promoter for Utility in AAV Vectors. Front Neurosci 2017; 11:521. [PMID: 28983234 PMCID: PMC5613148 DOI: 10.3389/fnins.2017.00521] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 09/04/2017] [Indexed: 12/13/2022] Open
Abstract
Significant advances in gene therapy have enabled exploration of therapies for inherited retinal disorders, many of which are in preclinical development or clinical evaluation. Gene therapy for retinal conditions has led the way in this growing field. The loss of retinal ganglion cells (RGCs) is a hallmark of a number of retinal disorders. As the field matures innovations that aid in refining therapies and optimizing efficacy are in demand. Gene therapies under development for RGC-related disorders, when delivered with recombinant adeno associated vectors (AAV), have typically been expressed from ubiquitous promoter sequences. Here we describe how a novel promoter from the murine Nefh gene was selected to drive transgene expression in RGCs. The Nefh promoter, in an AAV2/2 vector, was shown to drive preferential EGFP expression in murine RGCs in vivo following intravitreal injection. In contrast, EGFP expression from a CMV promoter was observed not only in RGCs, but throughout the inner nuclear layer and in amacrine cells located within the ganglion cell layer (GCL). Of note, the Nefh promoter sequence is sufficiently compact to be readily accommodated in AAV vectors, where transgene size represents a significant constraint. Moreover, this promoter should in principle provide a more targeted and potentially safer alternative for RGC-directed gene therapies.
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Affiliation(s)
- Killian S Hanlon
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - Naomi Chadderton
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - Arpad Palfi
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | | | - Peter Humphries
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - Paul F Kenna
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland.,Research Foundation, Royal Victoria Eye and Ear HospitalDublin, Ireland
| | - Sophia Millington-Ward
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
| | - G Jane Farrar
- School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College DublinDublin, Ireland
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31
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Leinonen H, Tanila H. Vision in laboratory rodents-Tools to measure it and implications for behavioral research. Behav Brain Res 2017; 352:172-182. [PMID: 28760697 DOI: 10.1016/j.bbr.2017.07.040] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/17/2017] [Accepted: 07/27/2017] [Indexed: 02/09/2023]
Abstract
Mice and rats are nocturnal mammals and their vision is specialized for detection of motion and contrast in dim light conditions. These species possess a large proportion of UV-sensitive cones in their retinas and the majority of their optic nerve axons target superior colliculus rather than visual cortex. Therefore, it was a widely held belief that laboratory rodents hardly utilize vision during day-time behavior. This dogma is being questioned as accumulating evidence suggests that laboratory rodents are able to perform complex visual functions, such as perceiving subjective contours, and that declined vision may affect their performance in many behavioral tasks. For instance, genetic engineering may have unexpected consequences on vision as mouse models of Alzheimer's and Huntington's diseases have declined visual function. Rodent vision can be tested in numerous ways using operant training or reflex-based behavioral tasks, or alternatively using electrophysiological recordings. In this article, we will first provide a summary of visual system and explain its characteristics unique to rodents. Then, we present well-established techniques to test rodent vision, with an emphasis on pattern vision: visual water test, optomotor reflex test, pattern electroretinography and pattern visual evoked potentials. Finally, we highlight the importance of visual phenotyping in rodents. As the number of genetically engineered rodent models and volume of behavioral testing increase simultaneously, the possibility of visual dysfunctions needs to be addressed. Neglect in this matter potentially leads to crude biases in the field of neuroscience and beyond.
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Affiliation(s)
- Henri Leinonen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Neulaniementie 2, 70211 Kuopio, Finland.
| | - Heikki Tanila
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, Neulaniementie 2, 70211 Kuopio, Finland
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32
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Kamel K, Farrell M, O'Brien C. Mitochondrial dysfunction in ocular disease: Focus on glaucoma. Mitochondrion 2017; 35:44-53. [PMID: 28499981 DOI: 10.1016/j.mito.2017.05.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/08/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Mitochondrial dysfunction commonly presents with ocular findings as a part of a systemic disorder. These ophthalmic manifestations can be the first sign of a mitochondrial abnormality, which highlights the key role of a comprehensive ophthalmic assessment. On the other hand, a number of visually disabling genetic and acquired eye diseases with no curative treatment show abnormal mitochondrial function. Recent advances in mitochondrial research have improved our understanding of previously unexplained ocular disorders utilising better diagnostic approaches. Further studies on mitochondrial dysfunction and novel modalities of treatment will help to improve outcomes of these conditions. In this review article we discuss the clinical picture of common mitochondrial-related eye diseases, diagnostic approaches and possible treatment options including a very recent interesting report about gene therapy, with a particular focus on glaucoma.
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Affiliation(s)
- Khalid Kamel
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | | | - Colm O'Brien
- Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.
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33
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Lv L, Wang Y, Feng W, Hernandez JA, Huang W, Zheng Y, Zhou X, Lv S, Chen Y, Yuan ZG. iTRAQ-based differential proteomic analysis in Mongolian gerbil brains chronically infected with Toxoplasma gondii. J Proteomics 2017; 160:74-83. [DOI: 10.1016/j.jprot.2017.03.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 02/13/2017] [Accepted: 03/13/2017] [Indexed: 12/12/2022]
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34
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Bi R, Logan I, Yao YG. Leber Hereditary Optic Neuropathy: A Mitochondrial Disease Unique in Many Ways. Handb Exp Pharmacol 2017; 240:309-336. [PMID: 27787713 DOI: 10.1007/164_2016_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Leber hereditary optic neuropathy (LHON) was the first mitochondrial disease to be identified as being caused by mutations in the mitochondrial DNA (mtDNA). This disease has been studied extensively in the past two decades, particularly in Brazilian, Chinese and European populations; and many primary mutations have been reported. However, the disease is enigmatic with many unique features, and there still are several important questions to be resolved. The incomplete penetrance, the male-biased disease expression and the prevalence in young adults all defy a proper explanation. It has been reported that the development of LHON is affected by the interaction between mtDNA mutations, mtDNA haplogroup background, nuclear genes, environmental factors and epigenetics. Furthermore, with the help of new animal models for LHON that have been created in recent years, we are continuing to learn more about the mechanism of this disease. The stage has now been reached at which there is a good understanding of both the genetic basis of the disease and its epidemiology, but just how the blindness that follows from the death of cells in the optic nerve can be prevented remains to be a pharmacological challenge. In this chapter, we summarize the progress that has been made in various recent studies on LHON, focusing on the molecular pathogenic mechanisms, clinical features, biochemical effects, the pharmacology and its treatment.
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Affiliation(s)
- Rui Bi
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | | | - Yong-Gang Yao
- Division of Medical Genetics & Evolutionary Medicine, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.
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35
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Abstract
The report in 1988 that Leber Hereditary Optic Neuropathy (LHON) was the product of mitochondrial DNA (mtDNA) mutations provided the first demonstration of the clinical relevance of inherited mtDNA variation. From LHON studies, the medical importance was demonstrated for the mtDNA showing its coding for the most important energy genes, its maternal inheritance, its high mutation rate, its presence in hundreds to thousands of copies per cell, its quantitatively segregation of biallelic genotypes during both mitosis and meiosis, its preferential effect on the most energetic tissues including the eye and brain, its wide range of functional polymorphisms that predispose to common diseases, and its accumulation of mutations within somatic tissues providing the aging clock. These features of mtDNA genetics, in combination with the genetics of the 1-2000 nuclear DNA (nDNA) coded mitochondrial genes, is not only explaining the genetics of LHON but also providing a model for understanding the complexity of many common diseases. With the maturation of LHON biology and genetics, novel animal models for complex disease have been developed and new therapeutic targets and strategies envisioned, both pharmacological and genetic. Multiple somatic gene therapy approaches are being developed for LHON which are applicable to other mtDNA diseases. Moreover, the unique cytoplasmic genetics of the mtDNA has permitted the first successful human germline gene therapy via spindle nDNA transfer from mtDNA mutant oocytes to enucleated normal mtDNA oocytes. Such LHON lessons are actively being applied to common ophthalmological diseases like glaucoma and neurological diseases like Parkinsonism.
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36
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Abstract
Leber hereditary optic neuropathy (LHON) was the first clinically characterized mitochondrial disorder. Since its first description in 1871, much has been discovered regarding the genetics and pathophysiology of the disease. This has enabled the development of in vitro cell and animal models that can be used to try to determine not only the effects of the genetic mutation upon the clinical phenotype but to also test potential novel therapies. Treatments for LHON have ranged from vitamins and minerals to immunosuppressants and, more recently, targeted gene therapy. This article reviews the pathophysiology and clinical features of LHON with a focus on translational research.
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Affiliation(s)
- Nailyn Rasool
- a Neuro-Ophthalmology Service, Massachusetts Eye and Ear Infirmary, Harvard Medical School , Boston , Massachusetts , USA
| | - Simmons Lessell
- a Neuro-Ophthalmology Service, Massachusetts Eye and Ear Infirmary, Harvard Medical School , Boston , Massachusetts , USA
| | - Dean M Cestari
- a Neuro-Ophthalmology Service, Massachusetts Eye and Ear Infirmary, Harvard Medical School , Boston , Massachusetts , USA
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Nightingale H, Pfeffer G, Bargiela D, Horvath R, Chinnery PF. Emerging therapies for mitochondrial disorders. Brain 2016; 139:1633-48. [PMID: 27190030 PMCID: PMC4892756 DOI: 10.1093/brain/aww081] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/26/2016] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial disorders are a diverse group of debilitating conditions resulting from nuclear and mitochondrial DNA mutations that affect multiple organs, often including the central and peripheral nervous system. Despite major advances in our understanding of the molecular mechanisms, effective treatments have not been forthcoming. For over five decades patients have been treated with different vitamins, co-factors and nutritional supplements, but with no proven benefit. There is therefore a clear need for a new approach. Several new strategies have been proposed acting at the molecular or cellular level. Whilst many show promise in vitro, the clinical potential of some is questionable. Here we critically appraise the most promising preclinical developments, placing the greatest emphasis on diseases caused by mitochondrial DNA mutations. With new animal and cellular models, longitudinal deep phenotyping in large patient cohorts, and growing interest from the pharmaceutical industry, the field is poised to make a breakthrough.
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Affiliation(s)
- Helen Nightingale
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Gerald Pfeffer
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK Department of Clinical Neurosciences, University of Calgary, Calgary, Canada Hotchkiss Brain Institute, at the University of Calgary, Calgary, Canada
| | - David Bargiela
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK MRC-Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0QQ, UK
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Yu-Wai-Man P. Genetic manipulation for inherited neurodegenerative diseases: myth or reality? Br J Ophthalmol 2016; 100:1322-31. [PMID: 27002113 PMCID: PMC5050284 DOI: 10.1136/bjophthalmol-2015-308329] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/28/2016] [Indexed: 12/22/2022]
Abstract
Rare genetic diseases affect about 7% of the general population and over 7000 distinct clinical syndromes have been described with the majority being due to single gene defects. This review will provide a critical overview of genetic strategies that are being pioneered to halt or reverse disease progression in inherited neurodegenerative diseases. This field of research covers a vast area and only the most promising treatment paradigms will be discussed with a particular focus on inherited eye diseases, which have paved the way for innovative gene therapy paradigms, and mitochondrial diseases, which are currently generating a lot of debate centred on the bioethics of germline manipulation.
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Affiliation(s)
- Patrick Yu-Wai-Man
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
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Abstract
PURPOSE OF REVIEW To discuss recent advances in potential treatments for Leber hereditary optic neuropathy (LHON), a typically visually devastating hereditary optic neuropathy caused by mutations in the mitochondrial genome. RECENT FINDINGS Idebenone has been proposed as a means of bypassing defective complex I activity and a free radical scavenger to prevent oxidative damage. EPI-743 may have more potency than idebenone, but no clinical trials have been performed. Gene therapy techniques have advanced significantly, including allotopic expression and nuclear transfer. Successful rescue of animal models of LHON with both of these therapies has been demonstrated. Introduction of exogenous DNA into the mitochondrial genome with mitochondrial targeting of viral vectors is another promising technique. SUMMARY There are currently no proven treatments for LHON. However, there are many promising novel treatment modalities that are currently being evaluated, with several clinical trials underway or in the planning stages. Supportive measures and genetic counseling remain of great importance for these patients.
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Dalkara D, Goureau O, Marazova K, Sahel JA. Let There Be Light: Gene and Cell Therapy for Blindness. Hum Gene Ther 2016; 27:134-47. [PMID: 26751519 PMCID: PMC4779297 DOI: 10.1089/hum.2015.147] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/06/2016] [Indexed: 12/14/2022] Open
Abstract
Retinal degenerative diseases are a leading cause of irreversible blindness. Retinal cell death is the main cause of vision loss in genetic disorders such as retinitis pigmentosa, Stargardt disease, and Leber congenital amaurosis, as well as in complex age-related diseases such as age-related macular degeneration. For these blinding conditions, gene and cell therapy approaches offer therapeutic intervention at various disease stages. The present review outlines advances in therapies for retinal degenerative disease, focusing on the progress and challenges in the development and clinical translation of gene and cell therapies. A significant body of preclinical evidence and initial clinical results pave the way for further development of these cutting edge treatments for patients with retinal degenerative disorders.
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Affiliation(s)
- Deniz Dalkara
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
| | - Olivier Goureau
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
| | - Katia Marazova
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de la Vision, France
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, France
- Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
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Feuer WJ, Schiffman JC, Davis JL, Porciatti V, Gonzalez P, Koilkonda RD, Yuan H, Lalwani A, Lam BL, Guy J. Gene Therapy for Leber Hereditary Optic Neuropathy: Initial Results. Ophthalmology 2015; 123:558-70. [PMID: 26606867 DOI: 10.1016/j.ophtha.2015.10.025] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 10/13/2015] [Accepted: 10/13/2015] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Leber hereditary optic neuropathy (LHON) is a disorder characterized by severe and rapidly progressive visual loss when caused by a mutation in the mitochondrial gene encoding NADH:ubiquinone oxidoreductase subunit 4 (ND4). We have initiated a gene therapy trial to determine the safety and tolerability of escalated doses of an adeno-associated virus vector (AAV) expressing a normal ND4 complementary DNA in patients with a G to A mutation at nucleotide 11778 of the mitochondrial genome. DESIGN In this prospective open-label trial (NCT02161380), the study drug (self-complementary AAV [scAAV]2(Y444,500,730F)-P1ND4v2) was intravitreally injected unilaterally into the eyes of 5 blind participants with G11778A LHON. Four participants with visual loss for more than 12 months were treated. The fifth participant had visual loss for less than 12 months. The first 3 participants were treated at the low dose of vector (5 × 10(9) vg), and the fourth participant was treated at the medium dose (2.46 × 10(10) vg). The fifth participant with visual loss for less than 12 months received the low dose. Treated participants were followed for 90 to 180 days and underwent ocular and systemic safety assessments along with visual structure and function examinations. PARTICIPANTS Five legally blind patients with G11778A LHON. MAIN OUTCOME MEASURES Loss of visual acuity. RESULTS Visual acuity as measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) eye chart remained unchanged from baseline to 3 months in the first 3 participants. For 2 participants with 90-day follow-up, acuity increased from hand movements to 7 letters in 1 and by 15 letters in 1, representing an improvement equivalent to 3 lines. No one lost vision, and no serious adverse events were observed. Minor adverse events included a transient increase of intraocular pressure (IOP), exposure keratitis, subconjunctival hemorrhage, a sore throat, and a transient increase in neutralizing antibodies (NAbs) against AAV2 in 1 participant. All blood samples were negative for vector DNA. CONCLUSIONS No serious safety problems were observed in the first 5 participants enrolled in this phase I trial of virus-based gene transfer in this mitochondrial disorder. Additional study follow-up of these and additional participants planned for the next 4 years is needed to confirm these preliminary observations.
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Affiliation(s)
- William J Feuer
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Joyce C Schiffman
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Janet L Davis
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Phillip Gonzalez
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Rajeshwari D Koilkonda
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Huijun Yuan
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Anil Lalwani
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - John Guy
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
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Rahman S. Emerging aspects of treatment in mitochondrial disorders. J Inherit Metab Dis 2015; 38:641-53. [PMID: 25962587 DOI: 10.1007/s10545-015-9855-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 11/26/2022]
Abstract
Mitochondrial diseases are clinically, biochemically and genetically heterogeneous disorders of two genomes, for which effective curative therapies are currently lacking. With the exception of a few rare vitamin/cofactor responsive conditions (including ACAD9 deficiency, disorders of coenzyme Q(10) biosynthesis, and Leigh syndrome caused by mutations in the SLC19A3 transporter), the mainstay of treatment for the vast majority of patients involves supportive measures. The search for a cure for mitochondrial disease is the subject of intensive research efforts by many investigators across the globe, but the goal remains elusive. The clinical and genetic heterogeneity, multisystemic nature of many of these disorders, unpredictable natural course, relative inaccessibility of the mitochondrion and lack of validated, clinically meaningful outcome measures, have all presented great challenges to the design of rigorous clinical trials. This review discusses barriers to developing effective therapies for mitochondrial disease, models for evaluating the efficacy of novel treatments and summarises the most promising emerging therapies in six key areas: 1) antioxidant approaches; 2) stimulating mitochondrial biogenesis; 3) targeting mitochondrial membrane lipids, dynamics and mitophagy; 4) replacement therapy; 5) cell-based therapies; and 6) gene therapy approaches for both mtDNA and nuclear-encoded defects of mitochondrial metabolism.
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Affiliation(s)
- Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine, Institute of Child Health, University College London and Metabolic Unit, Great Ormond Street Hospital, 30 Guilford Street, London, WC1N 1EH, UK,
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Cossard R, Esposito M, Sellem CH, Pitayu L, Vasnier C, Delahodde A, Dassa EP. Caenorhabditis elegans expressing the Saccharomyces cerevisiae NADH alternative dehydrogenase Ndi1p, as a tool to identify new genes involved in complex I related diseases. Front Genet 2015; 6:206. [PMID: 26124772 PMCID: PMC4463008 DOI: 10.3389/fgene.2015.00206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 05/26/2015] [Indexed: 11/17/2022] Open
Abstract
Isolated complex I deficiencies are one of the most commonly observed biochemical features in patients suffering from mitochondrial disorders. In the majority of these clinical cases the molecular bases of the diseases remain unknown suggesting the involvement of unidentified factors that are critical for complex I function. The Saccharomyces cerevisiae NDI1 gene, encoding the mitochondrial internal NADH dehydrogenase was previously shown to complement a complex I deficient strain in Caenorhabditis elegans with notable improvements in reproduction and whole organism respiration. These features indicate that Ndi1p can functionally integrate the respiratory chain, allowing complex I deficiency complementation. Taking into account the Ndi1p ability to bypass complex I, we evaluate the possibility to extend the range of defects/mutations causing complex I deficiencies that can be alleviated by NDI1 expression. We report here that NDI1 expressing animals unexpectedly exhibit a slightly shortened lifespan, a reduction in the progeny, and a depletion of the mitochondrial genome. However, Ndi1p is expressed and targeted to the mitochondria as a functional protein that confers rotenone resistance to those animals without affecting their respiration rate and ATP content. We show that the severe embryonic lethality level caused by the RNAi knockdowns of complex I structural subunit encoding genes (e.g., NDUFV1, NDUFS1, NDUFS6, NDUFS8, or GRIM-19 human orthologs) in wild type animals is significantly reduced in the Ndi1p expressing worm. All together these results open up the perspective to identify new genes involved in complex I function, assembly, or regulation by screening an RNAi library of genes leading to embryonic lethality that should be rescued by NDI1 expression.
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Affiliation(s)
- Raynald Cossard
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
| | - Michela Esposito
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
| | - Carole H Sellem
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
| | - Laras Pitayu
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
| | - Christelle Vasnier
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
| | - Agnès Delahodde
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
| | - Emmanuel P Dassa
- I2BC, Institute for Integrative Biology of the Cell, CEA, CNRS, Université Paris-Sud Orsay, France
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Palfi A, Chadderton N, O'Reilly M, Nagel-Wolfrum K, Wolfrum U, Bennett J, Humphries P, Kenna P, Millington-Ward S, Farrar J. Efficient gene delivery to photoreceptors using AAV2/rh10 and rescue of the Rho(-/-) mouse. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2015; 2:15016. [PMID: 26029727 PMCID: PMC4444994 DOI: 10.1038/mtm.2015.16] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/06/2015] [Accepted: 03/17/2015] [Indexed: 01/17/2023]
Abstract
As gene therapies for various forms of retinal degeneration progress toward human clinical trial, it will be essential to have a repertoire of safe and efficient vectors for gene delivery to the target cells. Recombinant adeno-associated virus (AAV) serotype 2/2 has been shown to be well tolerated in the human retina and has provided efficacy in human patients for some inherited retinal degenerations. In this study, the AAV2/8 and AAV2/rh10 serotypes have been compared as a means of gene delivery to mammalian photoreceptor cells using a photoreceptor specific promoter for transgene expression. Both AAV2/8 and AAV2/rh10 provided rescue of the retinal degeneration present in the rhodopsin knockout mouse, with similar levels of benefit as evaluated by molecular, histological, and functional readouts. Transgene expression levels were significantly higher (fivefold) 1 week postsubretinal injection when employing AAV2/8 for rhodopsin gene delivery compared to AAV2/rh10, and were indistinguishable by 6 weeks postadministration of vector. This study reports the use of the AAV2/rh10 serotype to provide rescue in a degenerating retina and provides a comparative evaluation of AAV2/rh10 with respect to AAV2/8, a serotype regarded as providing efficient delivery to photoreceptors.
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Affiliation(s)
- Arpad Palfi
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
| | - Naomi Chadderton
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
| | - Mary O'Reilly
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
| | - Kerstin Nagel-Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-Universität Mainz , Mainz, Germany
| | - Uwe Wolfrum
- Cell and Matrix Biology, Institute of Zoology, Johannes Gutenberg-Universität Mainz , Mainz, Germany
| | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, Perelman School Of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania, USA
| | - Peter Humphries
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
| | - Paul Kenna
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
| | - Sophia Millington-Ward
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
| | - Jane Farrar
- Department of Genetics, School of Genetics and Microbiology, Trinity College Dublin , Dublin 2, Ireland
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Therapeutic strategies for mitochondrial disorders. Pediatr Neurol 2015; 52:302-13. [PMID: 25701186 DOI: 10.1016/j.pediatrneurol.2014.06.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/14/2014] [Accepted: 06/19/2014] [Indexed: 12/31/2022]
Abstract
OBJECTIVES There is currently no curative therapy for mitochondrial disorders, although symptomatic measures can be highly effective and greatly improve the quality of life and outcome of these patients. This review highlights potential strategies for the therapeutic management of mitochondrial disorders. METHODS Data for this review were identified by searches of MEDLINE, Current Contents, using various relevant search terms. RESULTS Strategies to establish a therapeutic regimen aim to enhance respiratory chain function, eliminate noxious compounds, shift the heteroplasmy rate, alter mitochondrial dynamics, transfer cytoplasm, and promote gene therapy. Symptomatic measures rely on drugs (e.g., antiepileptics), avoidance of mitochondrion-toxic agents, substitution of blood cells, hemodialysis, invasive measures (such as a pacemaker), surgery (e.g., ptosis correction), physiotherapy, speech therapy, occupational therapy, dietary measures (e.g., ketogenic diet, anaplerotic diet), and the avoidance of mitochondrion-toxic agents (e.g., ozone). With the increasing awareness of mitochondrial disorders, the number of treatment studies is growing and its quality is improving. If high quality studies (high Jadad score) yield statistical significance for end points, a treatment is more reliable than with lower quality studies. CONCLUSIONS Despite the lack of a proven treatment for mitochondrial disorders, a nihilistic attitude toward treatment is not justified. A number of studies are seeking targeted therapies, and highly effective symptomatic measures are available.
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Nuclear expression of mitochondrial ND4 leads to the protein assembling in complex I and prevents optic atrophy and visual loss. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2015; 2:15003. [PMID: 26029714 PMCID: PMC4444999 DOI: 10.1038/mtm.2015.3] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/05/2015] [Accepted: 01/09/2015] [Indexed: 12/13/2022]
Abstract
Leber hereditary optic neuropathy is due to mitochondrial DNA mutations; in ~70% of all cases, a point mutation in the mitochondrial NADH dehydrogenase subunit 4, ND4, gene leads to central vision loss. We optimized allotopic expression (nuclear transcription of a gene that is normally transcribed inside the mitochondria) aimed at designing a gene therapy for ND4; its coding sequence was associated with the cis-acting elements of the human COX10 mRNA to allow the efficient mitochondrial delivery of the protein. After ocular administration to adult rats of a recombinant adeno-associated viral vector containing the human ND4 gene, we demonstrated that: (i) the sustained expression of human ND4 did not lead to harmful effects, instead the human protein is efficiently imported inside the mitochondria and assembled in respiratory chain complex I; (ii) the presence of the human protein in the experimental model of Leber hereditary optic neuropathy significantly prevents retinal ganglion cell degeneration and preserves both complex I function in optic nerves and visual function. Hence, the use of optimized allotopic expression is relevant for treating mitochondrial disorders due to mutations in the organelle genome.
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Thompson DA, Ali RR, Banin E, Branham KE, Flannery JG, Gamm DM, Hauswirth WW, Heckenlively JR, Iannaccone A, Jayasundera KT, Khan NW, Molday RS, Pennesi ME, Reh TA, Weleber RG, Zacks DN. Advancing therapeutic strategies for inherited retinal degeneration: recommendations from the Monaciano Symposium. Invest Ophthalmol Vis Sci 2015; 56:918-31. [PMID: 25667399 DOI: 10.1167/iovs.14-16049] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Although rare in the general population, retinal dystrophies occupy a central position in current efforts to develop innovative therapies for blinding diseases. This status derives, in part, from the unique biology, accessibility, and function of the retina, as well as from the synergy between molecular discoveries and transformative advances in functional assessment and retinal imaging. The combination of these factors has fueled remarkable progress in the field, while at the same time creating complex challenges for organizing collective efforts aimed at advancing translational research. The present position paper outlines recent progress in gene therapy and cell therapy for this group of disorders, and presents a set of recommendations for addressing the challenges remaining for the coming decade. It is hoped that the formulation of these recommendations will stimulate discussions among researchers, funding agencies, industry, and policy makers that will accelerate the development of safe and effective treatments for retinal dystrophies and related diseases.
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Affiliation(s)
- Debra A Thompson
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Robin R Ali
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States Division of Molecular Therapy, University College London Institute of Ophthalmology, London, England, United Kingdom
| | - Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Kari E Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - John G Flannery
- Helen Wills Neuroscience Institute, University of California-Berkeley, Berkeley, California, United States
| | - David M Gamm
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, Florida, United States
| | - John R Heckenlively
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Alessandro Iannaccone
- Department of Ophthalmology, Hamilton Eye Institute, University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - K Thiran Jayasundera
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Naheed W Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mark E Pennesi
- Casey Eye Institute and the Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, United States
| | - Thomas A Reh
- Department of Biological Structure, University of Washington, Seattle, Washington, United States
| | - Richard G Weleber
- Casey Eye Institute and the Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, United States Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon, United States
| | - David N Zacks
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States
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Trapani I, Puppo A, Auricchio A. Vector platforms for gene therapy of inherited retinopathies. Prog Retin Eye Res 2014; 43:108-28. [PMID: 25124745 PMCID: PMC4241499 DOI: 10.1016/j.preteyeres.2014.08.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 07/26/2014] [Accepted: 08/02/2014] [Indexed: 12/20/2022]
Abstract
Inherited retinopathies (IR) are common untreatable blinding conditions. Most of them are inherited as monogenic disorders, due to mutations in genes expressed in retinal photoreceptors (PR) and in retinal pigment epithelium (RPE). The retina's compatibility with gene transfer has made transduction of different retinal cell layers in small and large animal models via viral and non-viral vectors possible. The ongoing identification of novel viruses as well as modifications of existing ones based either on rational design or directed evolution have generated vector variants with improved transduction properties. Dozens of promising proofs of concept have been obtained in IR animal models with both viral and non-viral vectors, and some of them have been relayed to clinical trials. To date, recombinant vectors based on the adeno-associated virus (AAV) represent the most promising tool for retinal gene therapy, given their ability to efficiently deliver therapeutic genes to both PR and RPE and their excellent safety and efficacy profiles in humans. However, AAVs' limited cargo capacity has prevented application of the viral vector to treatments requiring transfer of genes with a coding sequence larger than 5 kb. Vectors with larger capacity, i.e. nanoparticles, adenoviral and lentiviral vectors are being exploited for gene transfer to the retina in animal models and, more recently, in humans. This review focuses on the available platforms for retinal gene therapy to fight inherited blindness, highlights their main strengths and examines the efforts to overcome some of their limitations.
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Affiliation(s)
- Ivana Trapani
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Agostina Puppo
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy.
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50
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Abstract
Significant advances have been made over the last decade or two in the elucidation of the molecular pathogenesis of inherited ocular disorders. In particular, remarkable successes have been achieved in exploration of gene-based medicines for these conditions, both in preclinical and in clinical studies. Progress in the development of gene therapies targeted toward correcting the primary genetic defect or focused on modulating secondary effects associated with retinal pathologies are discussed in the review. Likewise, the recent utilization of genes encoding light-sensing molecules to provide new functions to residual retinal cells in the degenerating retina is discussed. While a great deal has been learned over the last two decades, the next decade should result in an increasing number of preclinical studies progressing to human clinical trial, an exciting prospect for patients, those active in research and development and bystanders alike.
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