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Jia S, Liang R, Chen J, Liao S, Lin J, Li W. Emerging technology has a brilliant future: the CRISPR-Cas system for senescence, inflammation, and cartilage repair in osteoarthritis. Cell Mol Biol Lett 2024; 29:64. [PMID: 38698311 PMCID: PMC11067114 DOI: 10.1186/s11658-024-00581-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 04/19/2024] [Indexed: 05/05/2024] Open
Abstract
Osteoarthritis (OA), known as one of the most common types of aseptic inflammation of the musculoskeletal system, is characterized by chronic pain and whole-joint lesions. With cellular and molecular changes including senescence, inflammatory alterations, and subsequent cartilage defects, OA eventually leads to a series of adverse outcomes such as pain and disability. CRISPR-Cas-related technology has been proposed and explored as a gene therapy, offering potential gene-editing tools that are in the spotlight. Considering the genetic and multigene regulatory mechanisms of OA, we systematically review current studies on CRISPR-Cas technology for improving OA in terms of senescence, inflammation, and cartilage damage and summarize various strategies for delivering CRISPR products, hoping to provide a new perspective for the treatment of OA by taking advantage of CRISPR technology.
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Affiliation(s)
- Shicheng Jia
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, 518036, China
- Shantou University Medical College, Shantou, 515041, China
| | - Rongji Liang
- Shantou University Medical College, Shantou, 515041, China
| | - Jiayou Chen
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, 518036, China
- Shantou University Medical College, Shantou, 515041, China
| | - Shuai Liao
- Department of Bone and Joint, Peking University Shenzhen Hospital, Shenzhen, 518036, China
- Shenzhen University School of Medicine, Shenzhen, 518060, China
| | - Jianjing Lin
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, 518036, China.
| | - Wei Li
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, 518036, China.
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2
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Fragkoulis G, Hangas A, Fekete Z, Michell C, Moraes C, Willcox S, Griffith JD, Goffart S, Pohjoismäki JO. Linear DNA-driven recombination in mammalian mitochondria. Nucleic Acids Res 2024; 52:3088-3105. [PMID: 38300793 PMCID: PMC11014290 DOI: 10.1093/nar/gkae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 01/11/2024] [Indexed: 02/03/2024] Open
Abstract
Mitochondrial DNA (mtDNA) recombination in animals has remained enigmatic due to its uniparental inheritance and subsequent homoplasmic state, which excludes the biological need for genetic recombination, as well as limits tools to study it. However, molecular recombination is an important genome maintenance mechanism for all organisms, most notably being required for double-strand break repair. To demonstrate the existence of mtDNA recombination, we took advantage of a cell model with two different types of mitochondrial genomes and impaired its ability to degrade broken mtDNA. The resulting excess of linear DNA fragments caused increased formation of cruciform mtDNA, appearance of heterodimeric mtDNA complexes and recombinant mtDNA genomes, detectable by Southern blot and by long range PacBio® HiFi sequencing approach. Besides utilizing different electrophoretic methods, we also directly observed molecular complexes between different mtDNA haplotypes and recombination intermediates using transmission electron microscopy. We propose that the known copy-choice recombination by mitochondrial replisome could be sufficient for the needs of the small genome, thus removing the requirement for a specialized mitochondrial recombinase. The error-proneness of this system is likely to contribute to the formation of pathological mtDNA rearrangements.
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Affiliation(s)
- Georgios Fragkoulis
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
| | - Anu Hangas
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
| | - Zsófia Fekete
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
- Department of Genetics and Genomics, Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
- Doctoral School of Animal Biotechnology and Animal Science, Hungarian University of Agriculture and Life Sciences, Gödöllő, Hungary
| | - Craig Michell
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami,FL, USA
| | - Smaranda Willcox
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, USA
| | - Jack D Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, USA
| | - Steffi Goffart
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
| | - Jaakko L O Pohjoismäki
- Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland
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3
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Bacman SR, Barrera-Paez JD, Pinto M, Van Booven D, Stewart JB, Griswold AJ, Moraes CT. mitoTALEN reduces the mutant mtDNA load in neurons. Mol Ther Nucleic Acids 2024; 35:102132. [PMID: 38404505 PMCID: PMC10883830 DOI: 10.1016/j.omtn.2024.102132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024]
Abstract
Mutations within mtDNA frequently give rise to severe encephalopathies. Given that a majority of these mtDNA defects exist in a heteroplasmic state, we harnessed the precision of mitochondrial-targeted TALEN (mitoTALEN) to selectively eliminate mutant mtDNA within the CNS of a murine model harboring a heteroplasmic mutation in the mitochondrial tRNA alanine gene (m.5024C>T). This targeted approach was accomplished by the use of AAV-PHP.eB and a neuron-specific synapsin promoter for effective neuronal delivery and expression of mitoTALEN. We found that most CNS regions were effectively transduced and showed a significant reduction in mutant mtDNA. This reduction was accompanied by an increase in mitochondrial tRNA alanine levels, which are drastically reduced by the m.5024C>T mutation. These results showed that mitochondrial-targeted gene editing can be effective in reducing CNS-mutant mtDNA in vivo, paving the way for clinical trials in patients with mitochondrial encephalopathies.
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Affiliation(s)
- Sandra R. Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jose Domingo Barrera-Paez
- Graduate Program in Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Milena Pinto
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Derek Van Booven
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - James B. Stewart
- Biosciences Institute, Faculty of Medical Sciences, Wellcome Centre for Mitochondrial Research, Newcastle University, Newcastle upon Tyne, UK
| | - Anthony J. Griswold
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL, USA
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4
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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.
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5
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Shoop WK, Lape J, Trum M, Powell A, Sevigny E, Mischler A, Bacman SR, Fontanesi F, Smith J, Jantz D, Gorsuch CL, Moraes CT. Efficient elimination of MELAS-associated m.3243G mutant mitochondrial DNA by an engineered mitoARCUS nuclease. Nat Metab 2023; 5:2169-2183. [PMID: 38036771 PMCID: PMC10730414 DOI: 10.1038/s42255-023-00932-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 10/16/2023] [Indexed: 12/02/2023]
Abstract
Nuclease-mediated editing of heteroplasmic mitochondrial DNA (mtDNA) seeks to preferentially cleave and eliminate mutant mtDNA, leaving wild-type genomes to repopulate the cell and shift mtDNA heteroplasmy. Various technologies are available, but many suffer from limitations based on size and/or specificity. The use of ARCUS nucleases, derived from naturally occurring I-CreI, avoids these pitfalls due to their small size, single-component protein structure and high specificity resulting from a robust protein-engineering process. Here we describe the development of a mitochondrial-targeted ARCUS (mitoARCUS) nuclease designed to target one of the most common pathogenic mtDNA mutations, m.3243A>G. mitoARCUS robustly eliminated mutant mtDNA without cutting wild-type mtDNA, allowing for shifts in heteroplasmy and concomitant improvements in mitochondrial protein steady-state levels and respiration. In vivo efficacy was demonstrated using a m.3243A>G xenograft mouse model with mitoARCUS delivered systemically by adeno-associated virus. Together, these data support the development of mitoARCUS as an in vivo gene-editing therapeutic for m.3243A>G-associated diseases.
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Affiliation(s)
- Wendy K Shoop
- Precision BioSciences, Durham, NC, USA
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | | | | | | | | | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA
| | | | | | | | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA.
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6
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Yang L, Rathnam C, Hidaka T, Hou Y, Conklin B, Pandian GN, Sugiyama H, Lee KB. Nanoparticle-Based Artificial Mitochondrial DNA Transcription Regulator: MitoScript. Nano Lett 2023; 23:2046-2055. [PMID: 36688839 DOI: 10.1021/acs.nanolett.2c03958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The growing knowledge of the links between aberrant mitochondrial gene transcription and human diseases necessitates both an effective and dynamic approach to control mitochondrial DNA (mtDNA) transcription. To address this challenge, we developed a nanoparticle-based synthetic mitochondrial transcription regulator (MitoScript). MitoScript provides great colloidal stability, excellent biocompatibility, efficient cell uptake, and selective mitochondria targeting and can be monitored in live cells using near-infrared fluorescence. Notably, MitoScript controlled mtDNA transcription in a human cell line in an effective and selective manner. MitoScript targeting the light strand promoter region of mtDNA resulted in the downregulation of ND6 gene silencing, which eventually affected cell redox status, with considerably increased reactive oxygen species (ROS) generation. In summary, we developed MitoScript for the efficient, nonviral modification of mitochondrial DNA transcription. Our platform technology can potentially contribute to understanding the fundamental mechanisms of mitochondrial disorders and developing effective treatments for mitochondrial diseases.
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Affiliation(s)
- Letao Yang
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Christopher Rathnam
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Takuya Hidaka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Yannan Hou
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Brandon Conklin
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
| | - Ganesh N Pandian
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan
| | - Ki-Bum Lee
- Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Road, Piscataway, New Jersey 08854, United States
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7
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Liu Y, Huang Y, Xu C, An P, Luo Y, Jiao L, Luo J, Li Y. Mitochondrial Dysfunction and Therapeutic Perspectives in Cardiovascular Diseases. Int J Mol Sci 2022; 23:16053. [PMID: 36555691 PMCID: PMC9788331 DOI: 10.3390/ijms232416053] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/21/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
High mortality rates due to cardiovascular diseases (CVDs) have attracted worldwide attention. It has been reported that mitochondrial dysfunction is one of the most important mechanisms affecting the pathogenesis of CVDs. Mitochondrial DNA (mtDNA) mutations may result in impaired oxidative phosphorylation (OXPHOS), abnormal respiratory chains, and ATP production. In dysfunctional mitochondria, the electron transport chain (ETC) is uncoupled and the energy supply is reduced, while reactive oxygen species (ROS) production is increased. Here, we discussed and analyzed the relationship between mtDNA mutations, impaired mitophagy, decreased OXPHOS, elevated ROS, and CVDs from the perspective of mitochondrial dysfunction. Furthermore, we explored current potential therapeutic strategies for CVDs by eliminating mtDNA mutations (e.g., mtDNA editing and mitochondrial replacement), enhancing mitophagy, improving OXPHOS capacity (e.g., supplement with NAD+, nicotinamide riboside (NR), nicotinamide mononucleotide (NMN), and nano-drug delivery), and reducing ROS (e.g., supplement with Coenzyme Q10 and other antioxidants), and dissected their respective advantages and limitations. In fact, some therapeutic strategies are still a long way from achieving safe and effective clinical treatment. Although establishing effective and safe therapeutic strategies for CVDs remains challenging, starting from a mitochondrial perspective holds bright prospects.
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Affiliation(s)
- Yu Liu
- China Astronaut Research and Training Center, Beijing 100094, China
| | - Yuejia Huang
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Chong Xu
- China Astronaut Research and Training Center, Beijing 100094, China
| | - Peng An
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Yongting Luo
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Lei Jiao
- China Astronaut Research and Training Center, Beijing 100094, China
| | - Junjie Luo
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Yongzhi Li
- China Astronaut Research and Training Center, Beijing 100094, China
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8
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Shoop WK, Gorsuch CL, Bacman SR, Moraes CT. Precise and simultaneous quantification of mitochondrial DNA heteroplasmy and copy number by digital PCR. J Biol Chem 2022; 298:102574. [DOI: 10.1016/j.jbc.2022.102574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/01/2022] [Accepted: 10/05/2022] [Indexed: 11/09/2022] Open
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Mikhailov N, Hämäläinen RH. Modulating Mitochondrial DNA Heteroplasmy with Mitochondrially Targeted Endonucleases. Ann Biomed Eng 2022:10.1007/s10439-022-03051-7. [PMID: 36001180 DOI: 10.1007/s10439-022-03051-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/09/2022] [Indexed: 11/01/2022]
Abstract
Mitochondria, mainly known as energy factories of eukaryotic cells, also exert several additional signaling and metabolic functions and are today recognized as major cellular biosynthetic and signaling hubs. Mitochondria possess their own genome (mitochondrial DNA-mtDNA), that encodes proteins essential for oxidative phosphorylation, and mutations in it are an important contributor to human disease. The mtDNA mutations often exist in heteroplasmic conditions, with both healthy and mutant versions of the mtDNA residing in patients' cells and the level of mutant mtDNA may vary between different tissues and organs and affect the clinical outcome of the disease. Thus, shifting the ratio between healthy and mutant mtDNA in patients' cells provides an intriguing therapeutic option for mtDNA diseases. In this review we describe current strategies for modulating mitochondrial heteroplasmy levels with engineered endonucleases including mitochondrially targeted TALENs and Zinc finger nucleases (ZFNs) and discuss their therapeutic potential. These gene therapy tools could in the future provide therapeutic help both for patients with mitochondrial disease as well as in preventing the transfer of pathogenic mtDNA mutations from a mother to her offspring.
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Affiliation(s)
- Nikita Mikhailov
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland
| | - Riikka H Hämäläinen
- A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211, Kuopio, Finland.
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Di Donfrancesco A, Massaro G, Di Meo I, Tiranti V, Bottani E, Brunetti D. Gene Therapy for Mitochondrial Diseases: Current Status and Future Perspective. Pharmaceutics 2022; 14:1287. [PMID: 35745859 DOI: 10.3390/pharmaceutics14061287] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial diseases (MDs) are a group of severe genetic disorders caused by mutations in the nuclear or mitochondrial genome encoding proteins involved in the oxidative phosphorylation (OXPHOS) system. MDs have a wide range of symptoms, ranging from organ-specific to multisystemic dysfunctions, with different clinical outcomes. The lack of natural history information, the limits of currently available preclinical models, and the wide range of phenotypic presentations seen in MD patients have all hampered the development of effective therapies. The growing number of pre-clinical and clinical trials over the last decade has shown that gene therapy is a viable precision medicine option for treating MD. However, several obstacles must be overcome, including vector design, targeted tissue tropism and efficient delivery, transgene expression, and immunotoxicity. This manuscript offers a comprehensive overview of the state of the art of gene therapy in MD, addressing the main challenges, the most feasible solutions, and the future perspectives of the field.
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11
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Barrera-Paez JD, Moraes CT. Mitochondrial genome engineering coming-of-age. Trends Genet 2022; 38:869-880. [PMID: 35599021 PMCID: PMC9283244 DOI: 10.1016/j.tig.2022.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/11/2022] [Accepted: 04/27/2022] [Indexed: 12/16/2022]
Abstract
The mitochondrial genome has been difficult to manipulate because it is shielded by the organelle double membranes, preventing efficient nucleic acid entry. Moreover, mitochondrial DNA (mtDNA) recombination is not a robust system in most species. This limitation has forced investigators to rely on naturally occurring alterations to study both mitochondrial function and pathobiology. Because most pathogenic mtDNA mutations are heteroplasmic, the development of specific nucleases has allowed us to selectively eliminate mutant species. Several 'protein only' gene-editing platforms have been successfully used for this purpose. More recently, a DNA double-strand cytidine deaminase has been identified and adapted to edit mtDNA. This enzyme was also used as a component to adapt a DNA single-strand deoxyadenosine deaminase to mtDNA editing. These are major advances in our ability to precisely alter the mtDNA in animal cells.
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Saravanan S, Lewis CJ, Dixit B, O’connor MS, Stolzing A, Boominathan A. The Mitochondrial Genome in Aging and Disease and the Future of Mitochondrial Therapeutics. Biomedicines 2022; 10:490. [PMID: 35203698 PMCID: PMC8962324 DOI: 10.3390/biomedicines10020490] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/10/2022] [Accepted: 02/16/2022] [Indexed: 11/29/2022] Open
Abstract
Mitochondria are intracellular organelles that utilize nutrients to generate energy in the form of ATP by oxidative phosphorylation. Mitochondrial DNA (mtDNA) in humans is a 16,569 base pair double-stranded circular DNA that encodes for 13 vital proteins of the electron transport chain. Our understanding of the mitochondrial genome’s transcription, translation, and maintenance is still emerging, and human pathologies caused by mtDNA dysfunction are widely observed. Additionally, a correlation between declining mitochondrial DNA quality and copy number with organelle dysfunction in aging is well-documented in the literature. Despite tremendous advancements in nuclear gene-editing technologies and their value in translational avenues, our ability to edit mitochondrial DNA is still limited. In this review, we discuss the current therapeutic landscape in addressing the various pathologies that result from mtDNA mutations. We further evaluate existing gene therapy efforts, particularly allotopic expression and its potential to become an indispensable tool for restoring mitochondrial health in disease and aging.
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13
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Zhong G, Madry H, Cucchiarini M. Mitochondrial Genome Editing to Treat Human Osteoarthritis-A Narrative Review. Int J Mol Sci 2022; 23:1467. [PMID: 35163384 DOI: 10.3390/ijms23031467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 12/27/2022] Open
Abstract
Osteoarthritis (OA) is a severe, common chronic orthopaedic disorder characterised by a degradation of the articular cartilage with an incidence that increases over years. Despite the availability of various clinical options, none can stop the irreversible progression of the disease to definitely cure OA. Various mutations have been evidenced in the mitochondrial DNA (mtDNA) of cartilage cells (chondrocytes) in OA, leading to a dysfunction of the mitochondrial oxidative phosphorylation processes that significantly contributes to OA cartilage degeneration. The mitochondrial genome, therefore, represents a central, attractive target for therapy in OA, especially using genome editing procedures. In this narrative review article, we present and discuss the current advances and breakthroughs in mitochondrial genome editing as a potential, novel treatment to overcome mtDNA-related disorders such as OA. While still in its infancy and despite a number of challenges that need to be addressed (barriers to effective and site-specific mtDNA editing and repair), such a strategy has strong value to treat human OA in the future, especially using the groundbreaking clustered regularly interspaced short palindromic repeats (CRIPSR)/CRISPR-associated 9 (CRISPR/Cas9) technology and mitochondrial transplantation approaches.
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14
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Fu L, Luo YX, Liu Y, Liu H, Li HZ, Yu Y. Potential of Mitochondrial Genome Editing for Human Fertility Health. Front Genet 2021; 12:673951. [PMID: 34354734 PMCID: PMC8329452 DOI: 10.3389/fgene.2021.673951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 06/28/2021] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial DNA (mtDNA) encodes vital proteins and RNAs for the normal functioning of the mitochondria. Mutations in mtDNA leading to mitochondrial dysfunction are relevant to a large spectrum of diseases, including fertility disorders. Since mtDNA undergoes rather complex processes during gametogenesis and fertilization, clarification of the changes and functions of mtDNA and its essential impact on gamete quality and fertility during this process is of great significance. Thanks to the emergence and rapid development of gene editing technology, breakthroughs have been made in mitochondrial genome editing (MGE), offering great potential for the treatment of mtDNA-related diseases. In this review, we summarize the features of mitochondria and their unique genome, emphasizing their inheritance patterns; illustrate the role of mtDNA in gametogenesis and fertilization; and discuss potential therapies based on MGE as well as the outlook in this field.
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Affiliation(s)
- Lin Fu
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology and Key Laboratory of Assisted Reproduction, Ministry of Education, Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Yu-Xin Luo
- Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou, China
| | - Ying Liu
- Food Inspection and Quarantine Technology Center of Shenzhen Customs District, FICS, Shenzhen, China
| | - Hui Liu
- Stem Cell Research Center, Peking University Third Hospital, Beijing, China
| | - Hong-Zhen Li
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology and Key Laboratory of Assisted Reproduction, Ministry of Education, Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China
| | - Yang Yu
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology and Key Laboratory of Assisted Reproduction, Ministry of Education, Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, China.,Stem Cell Research Center, Peking University Third Hospital, Beijing, China
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15
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Abstract
Mitochondrial noncoding RNAs (mt-ncRNAs) include noncoding RNAs inside the mitochondria that are transcribed from the mitochondrial genome or nuclear genome, and noncoding RNAs transcribed from the mitochondrial genome that are transported to the cytosol or nucleus. Recent findings have revealed that mt-ncRNAs play important roles in not only mitochondrial functions, but also other cellular activities. This review proposes a classification of mt-ncRNAs and outlines the emerging understanding of mitochondrial circular RNAs (mt-circRNAs), mitochondrial microRNAs (mitomiRs), and mitochondrial long noncoding RNAs (mt-lncRNAs), with an emphasis on their identification and functions.
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Affiliation(s)
- Huixin Liang
- Department of Infectious Diseases, the Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Liver Disease Research, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Jiayu Liu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Shicheng Su
- Department of Infectious Diseases, the Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.,Breast Tumor Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.,Department of Immunology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Qiyi Zhao
- Department of Infectious Diseases, the Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Liver Disease Research, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
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16
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Zekonyte U, Bacman SR, Smith J, Shoop W, Pereira CV, Tomberlin G, Stewart J, Jantz D, Moraes CT. Mitochondrial targeted meganuclease as a platform to eliminate mutant mtDNA in vivo. Nat Commun 2021; 12:3210. [PMID: 34050192 DOI: 10.1038/s41467-021-23561-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 04/26/2021] [Indexed: 11/24/2022] Open
Abstract
Diseases caused by heteroplasmic mitochondrial DNA mutations have no effective treatment or cure. In recent years, DNA editing enzymes were tested as tools to eliminate mutant mtDNA in heteroplasmic cells and tissues. Mitochondrial-targeted restriction endonucleases, ZFNs, and TALENs have been successful in shifting mtDNA heteroplasmy, but they all have drawbacks as gene therapy reagents, including: large size, heterodimeric nature, inability to distinguish single base changes, or low flexibility and effectiveness. Here we report the adaptation of a gene editing platform based on the I-CreI meganuclease known as ARCUS®. These mitochondrial-targeted meganucleases (mitoARCUS) have a relatively small size, are monomeric, and can recognize sequences differing by as little as one base pair. We show the development of a mitoARCUS specific for the mouse m.5024C>T mutation in the mt-tRNAAla gene and its delivery to mice intravenously using AAV9 as a vector. Liver and skeletal muscle show robust elimination of mutant mtDNA with concomitant restoration of mt-tRNAAla levels. We conclude that mitoARCUS is a potential powerful tool for the elimination of mutant mtDNA. Heteroplasmic mitochondrial DNA mutations lack effective treatments. Here the authors adapt I-CreI meganuclease to target the mitochondria and specifically-eliminate mtDNA with a m.5024C>T mutation in the mttRNA Ala gene.
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17
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Amai T, Tsuji T, Ueda M, Kuroda K. Development of a mito-CRISPR system for generating mitochondrial DNA-deleted strain in Saccharomyces cerevisiae. Biosci Biotechnol Biochem 2021; 85:895-901. [PMID: 33580687 DOI: 10.1093/bbb/zbaa119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 12/22/2020] [Indexed: 11/13/2022]
Abstract
Mitochondrial dysfunction can occur in a variety of ways, most often due to the deletion or mutation of mitochondrial DNA (mtDNA). The easy generation of yeasts with mtDNA deletion is attractive for analyzing the functions of the mtDNA gene. Treatment of yeasts with ethidium bromide is a well-known method for generating ρ° cells with complete deletion of mtDNA from Saccharomyces cerevisiae. However, the mutagenic effects of ethidium bromide on the nuclear genome cannot be excluded. In this study, we developed a "mito-CRISPR system" that specifically generates ρ° cells of yeasts. This system enabled the specific cleavage of mtDNA by introducing Cas9 fused with the mitochondrial target sequence at the N-terminus and guide RNA into mitochondria, resulting in the specific generation of ρ° cells in yeasts. The mito-CRISPR system provides a concise technology for deleting mtDNA in yeasts.
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Affiliation(s)
- Takamitsu Amai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Tomoka Tsuji
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Kouichi Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
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18
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Abstract
Mitochondrial disorders make up a large class of heritable diseases that cause a broad array of different human pathologies. They can affect many different organ systems, or display very specific tissue presentation, and can lead to illness either in childhood or later in life. While the over 1200 genes encoded in the nuclear DNA play an important role in human mitochondrial disease, it has been known for over 30 years that mutations of the mitochondria's own small, multicopy DNA chromosome (mtDNA) can lead to heritable human diseases. Unfortunately, animal mtDNA has resisted transgenic and directed genome editing technologies until quite recently. As such, animal models to aid in our understanding of these diseases, and to explore preclinical therapeutic research have been quite rare. This review will discuss the unusual properties of animal mitochondria that have hindered the generation of animal models. It will also discuss the existing mammalian models of human mtDNA disease, describe the methods employed in their generation, and will discuss recent advances in the targeting of DNA-manipulating enzymes to the mitochondria and how these may be employed to generate new models.
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Affiliation(s)
- James Bruce Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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19
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Filograna R, Mennuni M, Alsina D, Larsson NG. Mitochondrial DNA copy number in human disease: the more the better? FEBS Lett 2020; 595:976-1002. [PMID: 33314045 PMCID: PMC8247411 DOI: 10.1002/1873-3468.14021] [Citation(s) in RCA: 180] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
Most of the genetic information has been lost or transferred to the nucleus during the evolution of mitochondria. Nevertheless, mitochondria have retained their own genome that is essential for oxidative phosphorylation (OXPHOS). In mammals, a gene‐dense circular mitochondrial DNA (mtDNA) of about 16.5 kb encodes 13 proteins, which constitute only 1% of the mitochondrial proteome. Mammalian mtDNA is present in thousands of copies per cell and mutations often affect only a fraction of them. Most pathogenic human mtDNA mutations are recessive and only cause OXPHOS defects if present above a certain critical threshold. However, emerging evidence strongly suggests that the proportion of mutated mtDNA copies is not the only determinant of disease but that also the absolute copy number matters. In this review, we critically discuss current knowledge of the role of mtDNA copy number regulation in various types of human diseases, including mitochondrial disorders, neurodegenerative disorders and cancer, and during ageing. We also provide an overview of new exciting therapeutic strategies to directly manipulate mtDNA to restore OXPHOS in mitochondrial diseases.
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Affiliation(s)
- Roberta Filograna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Mara Mennuni
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - David Alsina
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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20
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Wallace DC. CRISPR-Free Mitochondrial DNA Base Editing. CRISPR J 2020; 3:228-230. [PMID: 32833534 DOI: 10.1089/crispr.2020.29101.dwa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Affiliation(s)
- Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, Department of Pediatrics, Division of Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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21
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Silva-Pinheiro P, Cerutti R, Luna-Sanchez M, Zeviani M, Viscomi C. A Single Intravenous Injection of AAV-PHP.B- hNDUFS4 Ameliorates the Phenotype of Ndufs4 -/- Mice. Mol Ther Methods Clin Dev 2020; 17:1071-1078. [PMID: 32478122 PMCID: PMC7248291 DOI: 10.1016/j.omtm.2020.04.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 04/29/2020] [Indexed: 12/21/2022]
Abstract
Leigh syndrome, or infantile necrotizing subacute encephalopathy (OMIM #256000), is one of the most common manifestations of mitochondrial dysfunction, due to mutations in more than 75 genes, with mutations in respiratory complex I subunits being the most common cause. In the present study, we used the recently described PHP.B serotype, characterized by efficient capacity to cross the blood-brain barrier, to express the hNDUFS4 gene in the Ndufs4 -/- mouse model of Leigh disease. A single intravenous injection of PHP.B-hNDUFS4 in adult Ndufs4 -/- mice led to a normalization of the body weight, marked amelioration of the rotarod performance, delayed onset of neurodegeneration, and prolongation of the lifespan up to 1 year of age. hNDUFS4 protein was expressed in virtually all brain regions, leading to a partial recovery of complex I activity. Our findings strongly support the feasibility and effectiveness of adeno-associated viral vector (AAV)-mediated gene therapy for mitochondrial disease, particularly with new serotypes showing increased permeability to the blood-brain barrier in order to achieve widespread expression in the central nervous system.
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Affiliation(s)
- Pedro Silva-Pinheiro
- MRC/University of Cambridge Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | - Raffaele Cerutti
- MRC/University of Cambridge Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | - Marta Luna-Sanchez
- MRC/University of Cambridge Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
| | - Massimo Zeviani
- Department of Neurosciences, University of Padova, Via Giustiniani, 2, 35128 Padova, Italy
- Venetian Institute of Molecular Medicine, Via Orus, 2, 35128 Padova, Italy
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi, 58/B, 35131 Padova, Italy
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22
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Zekonyte U, Bacman SR, Moraes CT. DNA-editing enzymes as potential treatments for heteroplasmic mtDNA diseases. J Intern Med 2020; 287:685-697. [PMID: 32176378 PMCID: PMC7260085 DOI: 10.1111/joim.13055] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/04/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022]
Abstract
Mutations in the mitochondrial genome are the cause of many debilitating neuromuscular disorders. Currently, there is no cure or treatment for these diseases, and symptom management is the only relief doctors can provide. Although supplements and vitamins are commonly used in treatment, they provide little benefit to the patient and are only palliative. This is why gene therapy is a promising research topic to potentially treat and, in theory, even cure diseases caused by mutations in the mitochondrial DNA (mtDNA). Mammalian cells contain approximately a thousand copies of mtDNA, which can lead to a phenomenon called heteroplasmy, where both wild-type and mutant mtDNA molecules co-exist within the cell. Disease only manifests once the per cent of mutant mtDNA reaches a high threshold (usually >80%), which causes mitochondrial dysfunction and reduced ATP production. This is a useful feature to take advantage of for gene therapy applications, as not every mutant copy of mtDNA needs to be eliminated, but only enough to shift the heteroplasmic ratio below the disease threshold. Several DNA-editing enzymes have been used to shift heteroplasmy in cell culture and mice. This review provides an overview of these enzymes and discusses roadblocks of applying these to gene therapy in humans.
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Affiliation(s)
- U Zekonyte
- From the, Graduate Program in Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - S R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - C T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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23
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Naeem MM, Maheshan R, Costford SR, Wahedi A, Trajkovski M, Plavec J, Yatsunyk LA, Ciesielski GL, Kaufman BA, Sondheimer N. G-quadruplex-mediated reduction of a pathogenic mitochondrial heteroplasmy. Hum Mol Genet 2020; 28:3163-3174. [PMID: 31261379 DOI: 10.1093/hmg/ddz153] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/28/2019] [Accepted: 06/21/2019] [Indexed: 12/18/2022] Open
Abstract
Disease-associated variants in mitochondrial DNA (mtDNA) are frequently heteroplasmic, a state of co-existence with the wild-type genome. Because heteroplasmy correlates with the severity and penetrance of disease, improvement in the ratio between these genomes in favor of the wild-type, known as heteroplasmy shifting, is potentially therapeutic. We evaluated known pathogenic mtDNA variants and identified those with the potential for allele-specific differences in the formation of non-Watson-Crick G-quadruplex (GQ) structures. We found that the Leigh syndrome (LS)-associated m.10191C variant promotes GQ formation within local sequence in vitro. Interaction of this sequence with a small molecule GQ-binding agent, berberine hydrochloride, further increased GQ stability. The GQ formed at m.10191C differentially impeded the processivity of the mitochondrial DNA polymerase gamma (Pol γ) in vitro, providing a potential means to favor replication of the wild-type allele. We tested the potential for shifting heteroplasmy through the cyclical application of two different mitochondria-targeted GQ binding compounds in primary fibroblasts from patients with m.10191T>C heteroplasmy. Treatment induced alternating mtDNA depletion and repopulation and was effective in shifting heteroplasmy towards the non-pathogenic allele. Similar treatment of pathogenic heteroplasmies that do not affect GQ formation did not induce heteroplasmy shift. Following treatment, heteroplasmic m.10191T>C cells had persistent improvements and heteroplasmy and a corresponding increase in maximal mitochondrial oxygen consumption. This study demonstrates the potential for using small-molecule GQ-binding agents to induce genetic and functional improvements in m.10191T>C heteroplasmy.
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Affiliation(s)
| | - Rathena Maheshan
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Sheila R Costford
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Azizia Wahedi
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Marko Trajkovski
- National Institute of Chemistry, Slovenian NMR Center, Ljubljana, Slovenia
| | - Janez Plavec
- National Institute of Chemistry, Slovenian NMR Center, Ljubljana, Slovenia
| | - Liliya A Yatsunyk
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore PA, USA
| | | | - Brett A Kaufman
- Center for Metabolism and Mitochondrial Medicine, Division of Cardiology, Vascular Medicine Institute, Department of Medicine, University of Pittsburgh Medical School, Pittsburgh, PA, USA
| | - Neal Sondheimer
- Institute of Medical Science.,Departments of Paediatrics and Molecular Genetics, The University of Toronto, Toronto, ON, Canada.,Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
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24
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Cappa R, de Campos C, Maxwell AP, McKnight AJ. "Mitochondrial Toolbox" - A Review of Online Resources to Explore Mitochondrial Genomics. Front Genet 2020; 11:439. [PMID: 32457801 PMCID: PMC7225359 DOI: 10.3389/fgene.2020.00439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 04/09/2020] [Indexed: 12/30/2022] Open
Abstract
Mitochondria play a significant role in many biological systems. There is emerging evidence that differences in the mitochondrial genome may contribute to multiple common diseases, leading to an increasing number of studies exploring mitochondrial genomics. There is often a large amount of complex data generated (for example via next generation sequencing), which requires optimised bioinformatics tools to efficiently and effectively generate robust outcomes from these large datasets. Twenty-four online resources dedicated to mitochondrial genomics were reviewed. This 'mitochondrial toolbox' summary resource will enable researchers to rapidly identify the resource(s) most suitable for their needs. These resources fulfil a variety of functions, with some being highly specialised. No single tool will provide all users with the resources they require; therefore, the most suitable tool will vary between users depending on the nature of the work they aim to carry out. Genetics resources are well established for phylogeny and DNA sequence changes, but further epigenetic and gene expression resources need to be developed for mitochondrial genomics.
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Affiliation(s)
- Ruaidhri Cappa
- Centre for Public Health, Institute of Clinical Sciences B, Queen's University Belfast, Royal Victoria Hospital, Belfast, United Kingdom
| | - Cassio de Campos
- School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, Belfast, United Kingdom
| | - Alexander P Maxwell
- Centre for Public Health, Institute of Clinical Sciences B, Queen's University Belfast, Royal Victoria Hospital, Belfast, United Kingdom
| | - Amy J McKnight
- Centre for Public Health, Institute of Clinical Sciences B, Queen's University Belfast, Royal Victoria Hospital, Belfast, United Kingdom
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25
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Jackson CB, Turnbull DM, Minczuk M, Gammage PA. Therapeutic Manipulation of mtDNA Heteroplasmy: A Shifting Perspective. Trends Mol Med 2020; 26:698-709. [PMID: 32589937 DOI: 10.1016/j.molmed.2020.02.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/19/2020] [Accepted: 02/21/2020] [Indexed: 12/23/2022]
Abstract
Mutations of mitochondrial DNA (mtDNA) often underlie mitochondrial disease, one of the most common inherited metabolic disorders. Since the sequencing of the human mitochondrial genome and the discovery of pathogenic mutations in mtDNA more than 30 years ago, a movement towards generating methods for robust manipulation of mtDNA has ensued, although with relatively few advances and some controversy. While developments in the transformation of mammalian mtDNA have stood still for some time, recent demonstrations of programmable nuclease-based technology suggest that clinical manipulation of mtDNA heteroplasmy may be on the horizon for these largely untreatable disorders. Here we review historical and recent developments in mitochondrially targeted nuclease technology and the clinical outlook for treatment of hereditary mitochondrial disease.
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Affiliation(s)
- Christopher B Jackson
- Stem Cells and Metabolism, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Payam A Gammage
- CRUK Beatson Institute, Glasgow, UK; Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
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26
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Nissanka N, Moraes CT. Mitochondrial DNA heteroplasmy in disease and targeted nuclease-based therapeutic approaches. EMBO Rep 2020; 21:e49612. [PMID: 32073748 DOI: 10.15252/embr.201949612] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/11/2019] [Accepted: 01/29/2020] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial DNA (mtDNA) encodes a subset of the genes which are responsible for oxidative phosphorylation. Pathogenic mutations in the human mtDNA are often heteroplasmic, where wild-type mtDNA species co-exist with the pathogenic mtDNA and a bioenergetic defect is only seen when the pathogenic mtDNA percentage surpasses a threshold for biochemical manifestations. mtDNA segregation during germline development can explain some of the extreme variation in heteroplasmy from one generation to the next. Patients with high heteroplasmy for deleterious mtDNA species will likely suffer from bona-fide mitochondrial diseases, which currently have no cure. Shifting mtDNA heteroplasmy toward the wild-type mtDNA species could provide a therapeutic option to patients. Mitochondrially targeted engineered nucleases, such as mitoTALENs and mitoZFNs, have been used in vitro in human cells harboring pathogenic patient-derived mtDNA mutations and more recently in vivo in a mouse model of a pathogenic mtDNA point mutation. These gene therapy tools for shifting mtDNA heteroplasmy can also be used in conjunction with other therapies aimed at eliminating and/or preventing the transfer of pathogenic mtDNA from mother to child.
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Affiliation(s)
- Nadee Nissanka
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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27
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28
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Kotrys AV, Szczesny RJ. Mitochondrial Gene Expression and Beyond-Novel Aspects of Cellular Physiology. Cells 2019; 9:cells9010017. [PMID: 31861673 PMCID: PMC7017415 DOI: 10.3390/cells9010017] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 02/06/2023] Open
Abstract
Mitochondria are peculiar organelles whose proper function depends on the crosstalk between two genomes, mitochondrial and nuclear. The human mitochondrial genome (mtDNA) encodes only 13 proteins; nevertheless, its proper expression is essential for cellular homeostasis, as mtDNA-encoded proteins are constituents of mitochondrial respiratory complexes. In addition, mtDNA expression results in the production of RNA molecules, which influence cell physiology once released from the mitochondria into the cytoplasm. As a result, dysfunctions of mtDNA expression may lead to pathologies in humans. Here, we review the mechanisms of mitochondrial gene expression with a focus on recent findings in the field. We summarize the complex turnover of mitochondrial transcripts and present an increasing body of evidence indicating new functions of mitochondrial transcripts. We discuss mitochondrial gene regulation in different cellular contexts, focusing on stress conditions. Finally, we highlight the importance of emerging aspects of mitochondrial gene regulation in human health and disease.
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29
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Wallis CP, Scott LH, Filipovska A, Rackham O. Manipulating and elucidating mitochondrial gene expression with engineered proteins. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190185. [PMID: 31787043 DOI: 10.1098/rstb.2019.0185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Many conventional, modern genome engineering tools cannot be used to study mitochondrial genetics due to the unusual structure and physiology of the mitochondrial genome. Here, we review a number of newly developed, synthetic biology-based approaches for altering levels of mutant mammalian mitochondrial DNA and mitochondrial RNAs, including transcription activator-like effector nucleases, zinc finger nucleases and engineered RNA-binding proteins. These approaches allow researchers to manipulate and visualize mitochondrial processes and may provide future therapeutics. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.
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Affiliation(s)
- Christopher P Wallis
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia.,The University of Western Australia Centre for Medical Research, Crawley, Western Australia 6009, Australia
| | - Louis H Scott
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia.,The University of Western Australia Centre for Medical Research, Crawley, Western Australia 6009, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia.,The University of Western Australia Centre for Medical Research, Crawley, Western Australia 6009, Australia.,School of Molecular Sciences, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia.,School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, Western Australia 6102, Australia.,Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
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30
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Affiliation(s)
- Toshimasa Harumoto
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Narumi Shigi
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kouhei Tsumoto
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Makoto Komiyama
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, P. R. China
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31
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Pereira CV, Bacman SR, Arguello T, Zekonyte U, Williams SL, Edgell DR, Moraes CT. mitoTev-TALE: a monomeric DNA editing enzyme to reduce mutant mitochondrial DNA levels. EMBO Mol Med 2019; 10:emmm.201708084. [PMID: 30012581 PMCID: PMC6127889 DOI: 10.15252/emmm.201708084] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Pathogenic mitochondrial DNA (mtDNA) mutations often co‐exist with wild‐type molecules (mtDNA heteroplasmy). Phenotypes manifest when the percentage of mutant mtDNA is high (70–90%). Previously, our laboratory showed that mitochondria‐targeted transcription activator‐like effector nucleases (mitoTALENs) can eliminate mutant mtDNA from heteroplasmic cells. However, mitoTALENs are dimeric and relatively large, making it difficult to package their coding genes into viral vectors, limiting their clinical application. The smaller monomeric GIY‐YIG homing nuclease from T4 phage (I‐TevI) provides a potential alternative. We tested whether molecular hybrids (mitoTev‐TALEs) could specifically bind and cleave mtDNA of patient‐derived cybrids harboring different levels of the m.8344A>G mtDNA point mutation, associated with myoclonic epilepsy with ragged‐red fibers (MERRF). We tested two mitoTev‐TALE designs, one of which robustly shifted the mtDNA ratio toward the wild type. When this mitoTev‐TALE was tested in a clone with high levels of the MERRF mutation (91% mutant), the shift in heteroplasmy resulted in an improvement of oxidative phosphorylation function. mitoTev‐TALE provides an effective architecture for mtDNA editing that could facilitate therapeutic delivery of mtDNA editing enzymes to affected tissues.
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Affiliation(s)
- Claudia V Pereira
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Tania Arguello
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ugne Zekonyte
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Sion L Williams
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry University of Western Ontario, London, ON, Canada
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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Bacman SR, Kauppila JHK, Pereira CV, Nissanka N, Miranda M, Pinto M, Williams SL, Larsson NG, Stewart JB, Moraes CT. MitoTALEN reduces mutant mtDNA load and restores tRNA Ala levels in a mouse model of heteroplasmic mtDNA mutation. Nat Med 2018; 24:1696-700. [PMID: 30250143 DOI: 10.1038/s41591-018-0166-8] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/26/2018] [Indexed: 11/08/2022]
Abstract
Mutations in the mitochondrial DNA (mtDNA) are responsible for several metabolic disorders, commonly involving muscle and the central nervous system1. Because of the critical role of mtDNA in oxidative phosphorylation, the majority of pathogenic mtDNA mutations are heteroplasmic, co-existing with wild-type molecules1. Using a mouse model with a heteroplasmic mtDNA mutation2, we tested whether mitochondrial-targeted TALENs (mitoTALENs)3,4 could reduce the mutant mtDNA load in muscle and heart. AAV9-mitoTALEN was administered via intramuscular, intravenous, and intraperitoneal injections. Muscle and heart were efficiently transduced and showed a robust reduction in mutant mtDNA, which was stable over time. The molecular defect, namely a decrease in transfer RNAAla levels, was restored by the treatment. These results showed that mitoTALENs, when expressed in affected tissues, could revert disease-related phenotypes in mice.
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Hirano M, Emmanuele V, Quinzii CM. Emerging therapies for mitochondrial diseases. Essays Biochem 2018; 62:467-81. [PMID: 29980632 DOI: 10.1042/EBC20170114] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 05/20/2018] [Accepted: 05/23/2018] [Indexed: 12/25/2022]
Abstract
For the vast majority of patients with mitochondrial diseases, only supportive and symptomatic therapies are available. However, in the last decade, due to extraordinary advances in defining the causes and pathomechanisms of these diverse disorders, new therapies are being developed in the laboratory and are entering human clinical trials. In this review, we highlight the current use of dietary supplement and exercise therapies as well as emerging therapies that may be broadly applicable across multiple mitochondrial diseases or tailored for specific disorders. Examples of non-tailored therapeutic targets include: activation of mitochondrial biogenesis, regulation of mitophagy and mitochondrial dynamics, bypass of biochemical defects, mitochondrial replacement therapy, and hypoxia. In contrast, tailored therapies are: scavenging of toxic compounds, deoxynucleoside and deoxynucleotide treatments, cell replacement therapies, gene therapy, shifting mitochondrial DNA mutation heteroplasmy, and stabilization of mutant mitochondrial transfer RNAs.
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Nissanka N, Bacman SR, Plastini MJ, Moraes CT. The mitochondrial DNA polymerase gamma degrades linear DNA fragments precluding the formation of deletions. Nat Commun 2018; 9:2491. [PMID: 29950568 PMCID: PMC6021392 DOI: 10.1038/s41467-018-04895-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 05/25/2018] [Indexed: 02/03/2023] Open
Abstract
Double-strand breaks in the mitochondrial DNA (mtDNA) result in the formation of linear fragments that are rapidly degraded. However, the identity of the nuclease(s) performing this function is not known. We found that the exonuclease function of the mtDNA polymerase gamma (POLG) is required for this rapid degradation of mtDNA fragments. POLG is recruited to linearized DNA fragments in an origin of replication-independent manner. Moreover, in the absence of POLG exonuclease activity, the prolonged existence of mtDNA linear fragments leads to increased levels of mtDNA deletions, which have been previously identified in the mutator mouse, patients with POLG mutations and normal aging. Mitochondrial DNA fragments are rapidly degraded when double strand breaks occur. Here the authors reveal that the exonuclease activity of polymerase gamma is important for efficient degradation of these fragments and to avoid formation of large deletions.
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Affiliation(s)
- Nadee Nissanka
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Sandra R Bacman
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Melanie J Plastini
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Carlos T Moraes
- Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL, 33136, USA. .,Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Slone J, Gui B, Huang T. The current landscape for the treatment of mitochondrial disorders. J Genet Genomics 2018; 45:71-7. [DOI: 10.1016/j.jgg.2017.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/29/2017] [Accepted: 11/18/2017] [Indexed: 12/14/2022]
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Gammage PA, Moraes CT, Minczuk M. Mitochondrial Genome Engineering: The Revolution May Not Be CRISPR-Ized. Trends Genet 2018; 34:101-110. [PMID: 29179920 PMCID: PMC5783712 DOI: 10.1016/j.tig.2017.11.001] [Citation(s) in RCA: 196] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/28/2017] [Accepted: 11/02/2017] [Indexed: 12/17/2022]
Abstract
In recent years mitochondrial DNA (mtDNA) has transitioned to greater prominence across diverse areas of biology and medicine. The recognition of mitochondria as a major biochemical hub, contributions of mitochondrial dysfunction to various diseases, and several high-profile attempts to prevent hereditary mtDNA disease through mitochondrial replacement therapy have roused interest in the organellar genome. Subsequently, attempts to manipulate mtDNA have been galvanized, although with few robust advances and much controversy. Re-engineered protein-only nucleases such as mtZFN and mitoTALEN function effectively in mammalian mitochondria, although efficient delivery of nucleic acids into the organelle remains elusive. Such an achievement, in concert with a mitochondria-adapted CRISPR/Cas9 platform, could prompt a revolution in mitochondrial genome engineering and biological understanding. However, the existence of an endogenous mechanism for nucleic acid import into mammalian mitochondria, a prerequisite for mitochondrial CRISPR/Cas9 gene editing, remains controversial.
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Affiliation(s)
- Payam A Gammage
- Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - Carlos T Moraes
- Miller School of Medicine, University of Miami, Miami, FL, USA.
| | - Michal Minczuk
- Medical Research Council (MRC) Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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Yang Y, Wu H, Kang X, Liang Y, Lan T, Li T, Tan T, Peng J, Zhang Q, An G, Liu Y, Yu Q, Ma Z, Lian Y, Soh BS, Chen Q, Liu P, Chen Y, Sun X, Li R, Zhen X, Liu P, Yu Y, Li X, Fan Y. Targeted elimination of mutant mitochondrial DNA in MELAS-iPSCs by mitoTALENs. Protein Cell 2018; 9:283-297. [PMID: 29318513 PMCID: PMC5829275 DOI: 10.1007/s13238-017-0499-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/13/2017] [Indexed: 11/03/2022] Open
Abstract
Mitochondrial diseases are maternally inherited heterogeneous disorders that are primarily caused by mitochondrial DNA (mtDNA) mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy, mitochondrial defects can result in a wide spectrum of clinical manifestations. Mitochondria-targeted endonucleases provide an alternative avenue for treating mitochondrial disorders via targeted destruction of the mutant mtDNA and induction of heteroplasmic shifting. Here, we generated mitochondrial disease patient-specific induced pluripotent stem cells (MiPSCs) that harbored a high proportion of m.3243A>G mtDNA mutations and caused mitochondrial encephalomyopathy and stroke-like episodes (MELAS). We engineered mitochondrial-targeted transcription activator-like effector nucleases (mitoTALENs) and successfully eliminated the m.3243A>G mutation in MiPSCs. Off-target mutagenesis was not detected in the targeted MiPSC clones. Utilizing a dual fluorescence iPSC reporter cell line expressing a 3243G mutant mtDNA sequence in the nuclear genome, mitoTALENs displayed a significantly limited ability to target the nuclear genome compared with nuclear-localized TALENs. Moreover, genetically rescued MiPSCs displayed normal mitochondrial respiration and energy production. Moreover, neuronal progenitor cells differentiated from the rescued MiPSCs also demonstrated normal metabolic profiles. Furthermore, we successfully achieved reduction in the human m.3243A>G mtDNA mutation in porcine oocytes via injection of mitoTALEN mRNA. Our study shows the great potential for using mitoTALENs for specific targeting of mutant mtDNA both in iPSCs and mammalian oocytes, which not only provides a new avenue for studying mitochondrial biology and disease but also suggests a potential therapeutic approach for the treatment of mitochondrial disease, as well as the prevention of germline transmission of mutant mtDNA.
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Affiliation(s)
- Yi Yang
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Han Wu
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Xiangjin Kang
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Yanhui Liang
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Ting Lan
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Tianjie Li
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China
| | - Tao Tan
- Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, 650500, China
| | - Jiangyun Peng
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Quanjun Zhang
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Geng An
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Yali Liu
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Qian Yu
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Zhenglai Ma
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Ying Lian
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China
| | - Boon Seng Soh
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.,Disease Modeling and Therapeutics Laboratory, A*STAR Institute of Molecular and Cell Biology, 61 Biopolis Drive Proteos, Singapore, 138673, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Qingfeng Chen
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.,Disease Modeling and Therapeutics Laboratory, A*STAR Institute of Molecular and Cell Biology, 61 Biopolis Drive Proteos, Singapore, 138673, Singapore
| | - Ping Liu
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China
| | - Yaoyong Chen
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Xiaofang Sun
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Rong Li
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China
| | - Xiumei Zhen
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China
| | - Ping Liu
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China
| | - Yang Yu
- Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, 100191, China.
| | - Xiaoping Li
- Key Laboratory of Regenerative Biology of the Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cells and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.
| | - Yong Fan
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.
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Abstract
As a platform capable of mtDNA heteroplasmy manipulation, mitochondrially targeted zinc-finger nuclease (mtZFN) technology holds significant potential for the future of mitochondrial genome engineering, in both laboratory and clinic. Recent work highlights the importance of finely controlled mtZFN levels in mitochondria, permitting far greater mtDNA heteroplasmy modification efficiencies than observed in early applications. An initial approach, differential fluorescence-activated cell sorting (dFACS), allowing selection of transfected cells expressing various levels of mtZFN, demonstrated improved heteroplasmy modification. A further, key optimization has been the use of an engineered hammerhead ribozyme as a means for dynamic regulation of mtZFN expression, which has allowed the development of a unique isogenic cellular model of mitochondrial dysfunction arising from mutations in mtDNA, known as mTUNE. Protocols detailing these transformative optimizations are described in this chapter.
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Affiliation(s)
- Payam A Gammage
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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Abstract
Mitochondrial diseases often result from mutations in the mitochondrial genome (mtDNA). In most cases, mutant mtDNA coexists with wild-type mtDNA, resulting in heteroplasmy. One potential future approach to treat heteroplasmic mtDNA diseases is the specific elimination of pathogenic mtDNA mutations, lowering the level of mutant mtDNA below pathogenic thresholds. Mitochondrially targeted zinc-finger nucleases (mtZFNs) have been demonstrated to specifically target and introduce double-strand breaks in mutant mtDNA, facilitating substantial shifts in heteroplasmy. One application of mtZFN technology, in the context of heteroplasmic mtDNA disease, is delivery into the heteroplasmic oocyte or early embryo to eliminate mutant mtDNA, preventing transmission of mitochondrial diseases through the germline. Here we describe a protocol for efficient production of mtZFN mRNA in vitro, and delivery of these into 0.5 dpc mouse embryos to elicit shifts of mtDNA heteroplasmy.
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Affiliation(s)
- Beverly J McCann
- Mitochondrial Genetics Group, MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Andy Cox
- Mammalian Embryo and Stem Cell Group, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Payam A Gammage
- Mitochondrial Genetics Group, MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - James B Stewart
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Magdalena Zernicka-Goetz
- Mammalian Embryo and Stem Cell Group, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Michal Minczuk
- Mitochondrial Genetics Group, MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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Abstract
PURPOSE OF THE REVIEW The connections between allergy, asthma and metabolic syndrome are becoming increasingly clear. Recent research suggests a unifying mitochondrial link between the diverse phenotypes of these interlinked morbidities. The scope of this review is to highlight cellular mechanisms, epidemiology and environmental allergens influencing mitochondrial function and its importance in allergy and asthma. We briefly also consider the potential of mitochondria-targeted therapies in prevention and cure. RECENT FINDINGS Recent research has shown allergy, asthma and metabolic syndrome to be linked to mitochondrial dysfunction. Environmental pollutants and allergens are observed to cause mitochondrial dysfunction, primarily by inducing oxidative stress and ROS production. Malfunctioning mitochondria change the bioenergetics of the cell and its metabolic profile to favour systemic inflammation, which drives all three types of morbidities. Given the existing experimental evidence, approaches targeting mitochondria (e.g. antioxidant therapy and mitochondrial replacement) are being conducted in relevant disease models-with some progressing towards clinical trials, making mitochondrial function the focus of translational therapy research in asthma, allergy and linked metabolic syndrome.
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Affiliation(s)
- Divyaanka Iyer
- CSIR Institute of Genomics and Integrative Biology, Delhi University campus, Mall Road, Delhi, 110007, India
| | - Navya Mishra
- Indian Institute of Public Health, Gurugram, India.,Chest Research Foundation, Pune, India.,Academy of Scientific and Innovative Research, New Delhi, India
| | - Anurag Agrawal
- CSIR Institute of Genomics and Integrative Biology, Delhi University campus, Mall Road, Delhi, 110007, India. .,Academy of Scientific and Innovative Research, New Delhi, India.
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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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Abstract
Mitochondrial disease is a multifactorial disorder involving both nuclear and mitochondrial genomes. Over the past 20 years, great progress was achieved in the field of gene editing which raised the possibility of partial or complete elimination of mutant mtDNA that causes disease phenotypes. Each cell contains thousands of copies of mtDNA which can be either wild-type (WT) or mutant, a condition called heteroplasmy. As there are multiple copies of mtDNA inside a cell, the percentage of mutant mtDNA can vary and a directional shift in the heteroplasmy ratio towards an increase of WT mtDNA copies would have therapeutic value. Gene editing tools have been adapted to translocate to mitochondria and were able to change heteroplasmy in a predictable manner. These include mitochondrial targeted restriction endonucleases, Zinc-finger nucleases, and TAL-effector nucleases. These procedures could also be adapted to reduce the levels of mutant mtDNA in embryos, offering an option to the controversial mitochondrial replacement techniques during in vitro fertilization. The current strategies to induce heteroplasmy shift of mtDNA and its implications will be comprehensively discussed.
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Affiliation(s)
- Claudia V Pereira
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA,
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45
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Gammage PA, Gaude E, Van Haute L, Rebelo-Guiomar P, Jackson CB, Rorbach J, Pekalski ML, Robinson AJ, Charpentier M, Concordet JP, Frezza C, Minczuk M. Near-complete elimination of mutant mtDNA by iterative or dynamic dose-controlled treatment with mtZFNs. Nucleic Acids Res 2016; 44:7804-16. [PMID: 27466392 PMCID: PMC5027515 DOI: 10.1093/nar/gkw676] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 07/20/2016] [Indexed: 01/08/2023] Open
Abstract
Mitochondrial diseases are frequently associated with mutations in mitochondrial DNA (mtDNA). In most cases, mutant and wild-type mtDNAs coexist, resulting in heteroplasmy. The selective elimination of mutant mtDNA, and consequent enrichment of wild-type mtDNA, can rescue pathological phenotypes in heteroplasmic cells. Use of the mitochondrially targeted zinc finger-nuclease (mtZFN) results in degradation of mutant mtDNA through site-specific DNA cleavage. Here, we describe a substantial enhancement of our previous mtZFN-based approaches to targeting mtDNA, allowing near-complete directional shifts of mtDNA heteroplasmy, either by iterative treatment or through finely controlled expression of mtZFN, which limits off-target catalysis and undesired mtDNA copy number depletion. To demonstrate the utility of this improved approach, we generated an isogenic distribution of heteroplasmic cells with variable mtDNA mutant level from the same parental source without clonal selection. Analysis of these populations demonstrated an altered metabolic signature in cells harbouring decreased levels of mutant m.8993T>G mtDNA, associated with neuropathy, ataxia, and retinitis pigmentosa (NARP). We conclude that mtZFN-based approaches offer means for mtDNA heteroplasmy manipulation in basic research, and may provide a strategy for therapeutic intervention in selected mitochondrial diseases.
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Affiliation(s)
| | | | | | - Pedro Rebelo-Guiomar
- MRC Mitochondrial Biology Unit, Cambridge, UK GABBA, University of Porto, Portugal
| | | | | | - Marcin L Pekalski
- JDRF/Wellcome Trust DIL, Cambridge Institute for Medical Research, University of Cambridge, UK
| | | | - Marine Charpentier
- INSERM U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, Paris, France
| | - Jean-Paul Concordet
- INSERM U1154, CNRS UMR 7196, Muséum National d'Histoire Naturelle, Paris, France
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Abstract
Human mitochondria produce ATP and metabolites to support development and maintain cellular homeostasis. Mitochondria harbor multiple copies of a maternally inherited, non-nuclear genome (mtDNA) that encodes for 13 subunit proteins of the respiratory chain. Mutations in mtDNA occur mainly in the 24 non-coding genes, with specific mutations implicated in early death, neuromuscular and neurodegenerative diseases, cancer, and diabetes. A significant barrier to new insights in mitochondrial biology and clinical applications for mtDNA disorders is our general inability to manipulate the mtDNA sequence. Microinjection, cytoplasmic fusion, nucleic acid import strategies, targeted endonucleases, and newer approaches, which include the transfer of genomic DNA, somatic cell reprogramming, and a photothermal nanoblade, attempt to change the mtDNA sequence in target cells with varying efficiencies and limitations. Here, we discuss the current state of manipulating mammalian mtDNA and provide an outlook for mitochondrial reverse genetics, which could further enable mitochondrial research and therapies for mtDNA diseases.
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Affiliation(s)
- Alexander N Patananan
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | - Pei-Yu Chiou
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael A Teitell
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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47
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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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48
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Isakova EP, Deryabina YI, Leonovich OA, Zylkova MV, Biriukova IK. Study of the Accumulation of Rec A from Bacillus subtilis in the Mitochondria of a Recombinant Strain of the Yeast Yarovia lipolytica. APPL BIOCHEM MICRO+ 2016. [DOI: 10.1134/s0003683816020071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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49
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Abstract
Mammalian mitochondria contain multiple small genomes. While these organelles have efficient base excision removal of oxidative DNA lesions and alkylation damage, many DNA repair systems that work on nuclear DNA damage are not active in mitochondria. What is the fate of DNA damage in the mitochondria that cannot be repaired or that overwhelms the repair system? Some forms of mitochondrial DNA damage can apparently trigger mitochondrial DNA destruction, either via direct degradation or through specific forms of autophagy, such as mitophagy. However, accumulation of certain types of mitochondrial damage, in the absence of DNA ligase III (Lig3) or exonuclease G (EXOG), can directly trigger cell death. This review examines the cellular effects of persistent damage to mitochondrial genomes and discusses the very different cell fates that occur in response to different kinds of damage.
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Affiliation(s)
- Bennett Van Houten
- Department of Pharmacology Chemical Biology, University of Pittsburgh, 15213-1863,
| | - Senyene E Hunter
- School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27516
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC 27708-0328
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50
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Tischner C, Wenz T. Keep the fire burning: Current avenues in the quest of treating mitochondrial disorders. Mitochondrion 2015; 24:32-49. [DOI: 10.1016/j.mito.2015.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/18/2015] [Accepted: 06/24/2015] [Indexed: 12/18/2022]
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