1
|
Battista M, Carelli V, Bottazzi L, Bandello F, Cascavilla ML, Barboni P. Gene therapy for Leber hereditary optic neuropathy. Expert Opin Biol Ther 2024; 24:521-528. [PMID: 38939999 DOI: 10.1080/14712598.2024.2359015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 05/20/2024] [Indexed: 06/29/2024]
Abstract
INTRODUCTION Leber hereditary optic neuropathy (LHON) is among the most frequent inherited mitochondrial disease, causing a severe visual impairment, mostly in young-adult males. The causative mtDNA variants (the three common are m.11778 G>A/MT-ND4, m.3460 G>A/MT-ND1, and m.14484T>C/MT-ND6) by affecting complex I impair oxidative phosphorylation in retinal ganglion cells, ultimately leading to irreversible cell death and consequent functional loss. The gene therapy based on allotopic expression of a wild-type transgene carried by adeno-associated viral vectors (AVV-based) appears a promising approach in mitochondrial disease and its efficacy has been explored in several large clinical trials. AREAS COVERED The review work employed basic concepts in mitochondrial diseases, LHON, and gene therapy procedures. Reports from completed trials in LHON (i.e. RESCUE) were reviewed and critically compared. EXPERT OPINION New challenges, as the improvement of the contralateral untreated eye or the apparently better outcome in patients treated in later stages (6-12 months), were highlighted by the latest gene therapy trials. A better understanding of the pathogenetic mechanisms of the disease together with combined therapy (medical and gene therapy) and optimization in genetic correction approaches could improve the visual outcome of treated eyes.
Collapse
Affiliation(s)
- Marco Battista
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Valerio Carelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
- Programma di Neurogenetica, IRCCS Istituto di Scienze Neurologiche di Bologna, Bologna, Italy
| | - Leonardo Bottazzi
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Maria Lucia Cascavilla
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Piero Barboni
- Department of Ophthalmology, University Vita-Salute, IRCCS Ospedale San Raffaele, Milan, Italy
- Studio Oculistico d'Azeglio, Bologna, Italy
| |
Collapse
|
2
|
Lam BL. Leber hereditary optic neuropathy gene therapy. Curr Opin Ophthalmol 2024; 35:244-251. [PMID: 38117686 PMCID: PMC10959684 DOI: 10.1097/icu.0000000000001028] [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] [Indexed: 12/22/2023]
Abstract
PURPOSE OF REVIEW To discuss relevant clinical outcomes, challenges, and future opportunities of gene therapy in Leber hereditary optic neuropathy (LHON). RECENT FINDINGS Results of G11778A LHON Phase 3 randomized clinical trials with unilateral intravitreal rAAV2/2-ND4 allotopic gene therapy show good safety and unexpected bilateral partial improvements of BCVA (best-corrected visual acuity) with mean logMAR BCVA improvements of up to near ∼0.3 logMAR (3 lines) in the treated eyes and ∼0.25 logMAR (2.5 lines) in the sham-treated or placebo-treated fellow eyes. Final mean BCVA levels after gene therapy were in the range of ∼1.3 logMAR (20/400) bilaterally. SUMMARY Bilateral partial improvement with unilateral LHON gene therapy was unanticipated and may be due to treatment efficacy, natural history, learning effect, and other mediators. The overall efficacy is limited given the final BCVA levels. The sequential progressive visual loss and varied occurrence of spontaneous partial improvement in LHON confound trial results. Future clinical trials with randomization of patients to a group not receiving gene therapy in either eye would help to assess treatment effect. Promising future LHON gene therapy strategies include mitochondrially-targeted-sequence adeno-associated virus ('MTS-AAV') for direct delivery of the wild-type mitochondrial DNA into the mitochondria and CRISPR-free, RNA-free mitochondrial base editing systems. Signs of anatomical optic nerve damage and objective retinal ganglion cell dysfunction are evident in the asymptomatic eyes of LHON patients experiencing unilateral visual loss, indicating the therapeutic window is narrowing before onset of visual symptoms. Future treatment strategies utilizing mitochondrial base editing in LHON carriers without optic neuropathy holds the promise of a more advantageous approach to achieve optimal visual outcome by reducing disease penetrance and mitigating retinal ganglion cell loss when optic neuropathy develops.
Collapse
Affiliation(s)
- Byron L Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| |
Collapse
|
3
|
Gao Y, Guo L, Wang F, Wang Y, Li P, Zhang D. Development of mitochondrial gene-editing strategies and their potential applications in mitochondrial hereditary diseases: a review. Cytotherapy 2024; 26:11-24. [PMID: 37930294 DOI: 10.1016/j.jcyt.2023.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 11/07/2023]
Abstract
Mitochondrial DNA (mtDNA) is a critical genome contained within the mitochondria of eukaryotic cells, with many copies present in each mitochondrion. Mutations in mtDNA often are inherited and can lead to severe health problems, including various inherited diseases and premature aging. The lack of efficient repair mechanisms and the susceptibility of mtDNA to damage exacerbate the threat to human health. Heteroplasmy, the presence of different mtDNA genotypes within a single cell, increases the complexity of these diseases and requires an effective editing method for correction. Recently, gene-editing techniques, including programmable nucleases such as restriction endonuclease, zinc finger nuclease, transcription activator-like effector nuclease, clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated 9 and base editors, have provided new tools for editing mtDNA in mammalian cells. Base editors are particularly promising because of their high efficiency and precision in correcting mtDNA mutations. In this review, we discuss the application of these techniques in mitochondrial gene editing and their limitations. We also explore the potential of base editors for mtDNA modification and discuss the opportunities and challenges associated with their application in mitochondrial gene editing. In conclusion, this review highlights the advancements, limitations and opportunities in current mitochondrial gene-editing technologies and approaches. Our insights aim to stimulate the development of new editing strategies that can ultimately alleviate the adverse effects of mitochondrial hereditary diseases.
Collapse
Affiliation(s)
- Yanyan Gao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Linlin Guo
- The Affiliated Cardiovascular Hospital of Qingdao University, Qingdao University, Qingdao, China
| | - Fei Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Dejiu Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.
| |
Collapse
|
4
|
Keshavan N, Minczuk M, Viscomi C, Rahman S. Gene therapy for mitochondrial disorders. J Inherit Metab Dis 2024; 47:145-175. [PMID: 38171948 DOI: 10.1002/jimd.12699] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/30/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024]
Abstract
In this review, we detail the current state of application of gene therapy to primary mitochondrial disorders (PMDs). Recombinant adeno-associated virus-based (rAAV) gene replacement approaches for nuclear gene disorders have been undertaken successfully in more than ten preclinical mouse models of PMDs which has been made possible by the development of novel rAAV technologies that achieve more efficient organ targeting. So far, however, the greatest progress has been made for Leber Hereditary Optic Neuropathy, for which phase 3 clinical trials of lenadogene nolparvovec demonstrated efficacy and good tolerability. Other methods of treating mitochondrial DNA (mtDNA) disorders have also had traction, including refinements to nucleases that degrade mtDNA molecules with pathogenic variants, including transcription activator-like effector nucleases, zinc-finger nucleases, and meganucleases (mitoARCUS). rAAV-based approaches have been used successfully to deliver these nucleases in vivo in mice. Exciting developments in CRISPR-Cas9 gene editing technology have achieved in vivo gene editing in mouse models of PMDs due to nuclear gene defects and new CRISPR-free gene editing approaches have shown great potential for therapeutic application in mtDNA disorders. We conclude the review by discussing the challenges of translating gene therapy in patients both from the point of view of achieving adequate organ transduction as well as clinical trial design.
Collapse
Affiliation(s)
- Nandaki Keshavan
- UCL Great Ormond Street Institute of Child Health, London, UK
- Great Ormond Street Hospital, London, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Shamima Rahman
- UCL Great Ormond Street Institute of Child Health, London, UK
- Great Ormond Street Hospital, London, UK
| |
Collapse
|
5
|
Arjomandnejad M, Dasgupta I, Flotte TR, Keeler AM. Immunogenicity of Recombinant Adeno-Associated Virus (AAV) Vectors for Gene Transfer. BioDrugs 2023; 37:311-329. [PMID: 36862289 PMCID: PMC9979149 DOI: 10.1007/s40259-023-00585-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2023] [Indexed: 03/03/2023]
Abstract
Recombinant adeno-associated viruses (AAVs) have emerged as promising gene delivery vehicles resulting in three US Food and Drug Administration (FDA) and one European Medicines Agency (EMA)-approved AAV-based gene therapies. Despite being a leading platform for therapeutic gene transfer in several clinical trials, host immune responses against the AAV vector and transgene have hampered their widespread application. Multiple factors, including vector design, dose, and route of administration, contribute to the overall immunogenicity of AAVs. The immune responses against the AAV capsid and transgene involve an initial innate sensing. The innate immune response subsequently triggers an adaptive immune response to elicit a robust and specific response against the AAV vector. AAV gene therapy clinical trials and preclinical studies provide important information about the immune-mediated toxicities associated with AAV, yet studies suggest preclinical models fail to precisely predict the outcome of gene delivery in humans. This review discusses the contribution of the innate and adaptive immune response against AAVs, highlighting the challenges and potential strategies to mitigate these responses, thereby enhancing the therapeutic potential of AAV gene therapy.
Collapse
Affiliation(s)
- Motahareh Arjomandnejad
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, 386 Plantation Street, Worcester, MA, 01605, USA
| | - Ishani Dasgupta
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, 386 Plantation Street, Worcester, MA, 01605, USA
| | - Terence R Flotte
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, 386 Plantation Street, Worcester, MA, 01605, USA
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Allison M Keeler
- Horae Gene Therapy Center, University of Massachusetts Chan Medical School, 386 Plantation Street, Worcester, MA, 01605, USA.
- Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA, USA.
- NeuroNexus Institute, University of Massachusetts Chan Medical School, Worcester, MA, USA.
| |
Collapse
|