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Keshavan N, Minczuk M, Viscomi C, Rahman S. Gene therapy for mitochondrial disorders. J Inherit Metab Dis 2024; 47:145-175. [PMID: 38171948 DOI: 10.1002/jimd.12699] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/30/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024]
Abstract
In this review, we detail the current state of application of gene therapy to primary mitochondrial disorders (PMDs). Recombinant adeno-associated virus-based (rAAV) gene replacement approaches for nuclear gene disorders have been undertaken successfully in more than ten preclinical mouse models of PMDs which has been made possible by the development of novel rAAV technologies that achieve more efficient organ targeting. So far, however, the greatest progress has been made for Leber Hereditary Optic Neuropathy, for which phase 3 clinical trials of lenadogene nolparvovec demonstrated efficacy and good tolerability. Other methods of treating mitochondrial DNA (mtDNA) disorders have also had traction, including refinements to nucleases that degrade mtDNA molecules with pathogenic variants, including transcription activator-like effector nucleases, zinc-finger nucleases, and meganucleases (mitoARCUS). rAAV-based approaches have been used successfully to deliver these nucleases in vivo in mice. Exciting developments in CRISPR-Cas9 gene editing technology have achieved in vivo gene editing in mouse models of PMDs due to nuclear gene defects and new CRISPR-free gene editing approaches have shown great potential for therapeutic application in mtDNA disorders. We conclude the review by discussing the challenges of translating gene therapy in patients both from the point of view of achieving adequate organ transduction as well as clinical trial design.
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Affiliation(s)
- Nandaki Keshavan
- UCL Great Ormond Street Institute of Child Health, London, UK
- Great Ormond Street Hospital, London, UK
| | - Michal Minczuk
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- Veneto Institute of Molecular Medicine (VIMM), Padova, Italy
| | - Shamima Rahman
- UCL Great Ormond Street Institute of Child Health, London, UK
- Great Ormond Street Hospital, London, UK
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2
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Averina OA, Kuznetsova SA, Permyakov OA, Sergiev PV. Animal Models of Mitochondrial Diseases Associated with Nuclear Gene Mutations. Acta Naturae 2023; 15:4-22. [PMID: 38234606 PMCID: PMC10790356 DOI: 10.32607/actanaturae.25442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 10/05/2023] [Indexed: 01/19/2024] Open
Abstract
Mitochondrial diseases (MDs) associated with nuclear gene mutations are part of a large group of inherited diseases caused by the suppression of energy metabolism. These diseases are of particular interest, because nuclear genes encode not only most of the structural proteins of the oxidative phosphorylation system (OXPHOS), but also all the proteins involved in the OXPHOS protein import from the cytoplasm and their assembly in mitochondria. Defects in any of these proteins can lead to functional impairment of the respiratory chain, including dysfunction of complex I that plays a central role in cellular respiration and oxidative phosphorylation, which is the most common cause of mitopathologies. Mitochondrial diseases are characterized by an early age of onset and a progressive course and affect primarily energy-consuming tissues and organs. The treatment of MDs should be initiated as soon as possible, but the diagnosis of mitopathologies is extremely difficult because of their heterogeneity and overlapping clinical features. The molecular pathogenesis of mitochondrial diseases is investigated using animal models: i.e. animals carrying mutations causing MD symptoms in humans. The use of mutant animal models opens new opportunities in the study of genes encoding mitochondrial proteins, as well as the molecular mechanisms of mitopathology development, which is necessary for improving diagnosis and developing approaches to drug therapy. In this review, we present the most recent information on mitochondrial diseases associated with nuclear gene mutations and animal models developed to investigate them.
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Affiliation(s)
- O. A. Averina
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - S. A. Kuznetsova
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - O. A. Permyakov
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - P. V. Sergiev
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
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3
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Wanrooij PH, Chabes A. NME6: ribonucleotide salvage sustains mitochondrial transcription. EMBO J 2023; 42:e114990. [PMID: 37548337 PMCID: PMC10505902 DOI: 10.15252/embj.2023114990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/08/2023] Open
Abstract
The building blocks for RNA and DNA are made in the cytosol, meaning mitochondria depend on the import and salvage of ribonucleoside triphosphates (rNTPs) and deoxyribonucleoside triphosphates (dNTPs) for the synthesis of their own genetic material. While extensive research has focused on mitochondrial dNTP homeostasis due to its defects being associated with various mitochondrial DNA (mtDNA) depletion and deletion syndromes, the investigation of mitochondrial rNTP homeostasis has received relatively little attention. In this issue of the EMBO Journal, Grotehans et al provide compelling evidence of a major role for NME6, a mitochondrial nucleoside diphosphate kinase, in the conversion of pyrimidine ribonucleoside diphosphates into the corresponding triphosphates. These data also suggest a significant physiological role for NME6, as its absence results in the depletion of mitochondrial transcripts and destabilization of the electron transport chain (Grotehans et al, 2023).
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Affiliation(s)
- Paulina H Wanrooij
- Department of Medical Biochemistry and BiophysicsUmeå UniversityUmeåSweden
| | - Andrei Chabes
- Department of Medical Biochemistry and BiophysicsUmeå UniversityUmeåSweden
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4
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Olkhova EA, Smith LA, Bradshaw C, Gorman GS, Erskine D, Ng YS. Neurological Phenotypes in Mouse Models of Mitochondrial Disease and Relevance to Human Neuropathology. Int J Mol Sci 2023; 24:ijms24119698. [PMID: 37298649 DOI: 10.3390/ijms24119698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 05/24/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Mitochondrial diseases represent the most common inherited neurometabolic disorders, for which no effective therapy currently exists for most patients. The unmet clinical need requires a more comprehensive understanding of the disease mechanisms and the development of reliable and robust in vivo models that accurately recapitulate human disease. This review aims to summarise and discuss various mouse models harbouring transgenic impairments in genes that regulate mitochondrial function, specifically their neurological phenotype and neuropathological features. Ataxia secondary to cerebellar impairment is one of the most prevalent neurological features of mouse models of mitochondrial dysfunction, consistent with the observation that progressive cerebellar ataxia is a common neurological manifestation in patients with mitochondrial disease. The loss of Purkinje neurons is a shared neuropathological finding in human post-mortem tissues and numerous mouse models. However, none of the existing mouse models recapitulate other devastating neurological phenotypes, such as refractory focal seizures and stroke-like episodes seen in patients. Additionally, we discuss the roles of reactive astrogliosis and microglial reactivity, which may be driving the neuropathology in some of the mouse models of mitochondrial dysfunction, as well as mechanisms through which cellular death may occur, beyond apoptosis, in neurons undergoing mitochondrial bioenergy crisis.
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Affiliation(s)
- Elizaveta A Olkhova
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Laura A Smith
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Carla Bradshaw
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, UK
- NIHR Newcastle Biomedical Research Centre, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Daniel Erskine
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- NIHR Newcastle Biomedical Research Centre, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, UK
- NIHR Newcastle Biomedical Research Centre, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
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5
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Harada N, Nagasaki H, Yamamoto H, Matsubara K, Suzuki T, Gomori A, Yokogawa T, Matsuo K, Miyadera K. Depletion of plasma thymidine results in growth retardation and mitochondrial myopathy in mice overexpressing human thymidine phosphorylase. J Biol Chem 2023; 299:103002. [PMID: 36773803 PMCID: PMC10020661 DOI: 10.1016/j.jbc.2023.103002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
Abstract
Plasma thymidine levels in rodents are higher than in other mammals including humans, possibly due to a different pattern and lower level of thymidine phosphorylase expression. Here, we generated a novel knock-in (KI) mouse line with high systemic expression of human thymidine phosphorylase to investigate this difference in nucleotide metabolism in rodents. The KI mice showed growth retardation around weaning and died by 4 weeks of age with a decrease in plasma thymidine level compared with the litter-control WT mice. These phenotypes were completely or partially rescued by administration of the thymidine phosphorylase inhibitor 5-chloro-6-(2-iminopyrrolidin-1-yl) methyl-2,4(1H,3H)-pyrimidinedione hydrochloride or thymidine, respectively. Interestingly, when thymidine phosphorylase inhibitor administration was discontinued in adult animals, KI mice showed deteriorated grip strength and locomotor activity, decreased bodyweight, and subsequent hind-limb paralysis. Upon histological analyses, we observed axonal degeneration in the spinal cord, muscular atrophy with morphologically abnormal mitochondria in quadriceps, retinal degeneration, and abnormality in the exocrine pancreas. Moreover, we detected mitochondrial DNA depletion in multiple tissues of KI mice. These results indicate that the KI mouse represents a new animal model for mitochondrial diseases and should be applicable for the study of differences in nucleotide metabolism between humans and mice.
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Affiliation(s)
- Naomoto Harada
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan.
| | - Haruka Nagasaki
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Hiromi Yamamoto
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Kenji Matsubara
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Takamasa Suzuki
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Akira Gomori
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Tatsushi Yokogawa
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Kenichi Matsuo
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
| | - Kazutaka Miyadera
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co Ltd, Tsukuba, Ibaraki, Japan
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6
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Uusimaa J, Kettunen J, Varilo T, Järvelä I, Kallijärvi J, Kääriäinen H, Laine M, Lapatto R, Myllynen P, Niinikoski H, Rahikkala E, Suomalainen A, Tikkanen R, Tyynismaa H, Vieira P, Zarybnicky T, Sipilä P, Kuure S, Hinttala R. The Finnish genetic heritage in 2022 – from diagnosis to translational research. Dis Model Mech 2022; 15:278566. [PMID: 36285626 PMCID: PMC9637267 DOI: 10.1242/dmm.049490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Isolated populations have been valuable for the discovery of rare monogenic diseases and their causative genetic variants. Finnish disease heritage (FDH) is an example of a group of hereditary monogenic disorders caused by single major, usually autosomal-recessive, variants enriched in the population due to several past genetic drift events. Interestingly, distinct subpopulations have remained in Finland and have maintained their unique genetic repertoire. Thus, FDH diseases have persisted, facilitating vigorous research on the underlying molecular mechanisms and development of treatment options. This Review summarizes the current status of FDH, including the most recently discovered FDH disorders, and introduces a set of other recently identified diseases that share common features with the traditional FDH diseases. The Review also discusses a new era for population-based studies, which combine various forms of big data to identify novel genotype–phenotype associations behind more complex conditions, as exemplified here by the FinnGen project. In addition to the pathogenic variants with an unequivocal causative role in the disease phenotype, several risk alleles that correlate with certain phenotypic features have been identified among the Finns, further emphasizing the broad value of studying genetically isolated populations.
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Affiliation(s)
- Johanna Uusimaa
- Children and Adolescents, Oulu University Hospital 1 , 90029 Oulu , Finland
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
| | - Johannes Kettunen
- Computational Medicine, Center for Life Course Health Research, University of Oulu 3 , 90014 Oulu , Finland
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare 4 , 00271 Helsinki
- Finland 4 , 00271 Helsinki
- Biocenter Oulu, University of Oulu 5 , 90014 Oulu , Finland
| | - Teppo Varilo
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare 4 , 00271 Helsinki
- Finland 4 , 00271 Helsinki
- Department of Medical Genetics, University of Helsinki 6 , 00251 Helsinki , Finland
| | - Irma Järvelä
- Department of Medical Genetics, University of Helsinki 6 , 00251 Helsinki , Finland
| | - Jukka Kallijärvi
- Folkhälsan Institute of Genetics, Folkhälsan Research Center 7 , 00014 Helsinki , Finland
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
| | - Helena Kääriäinen
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare 4 , 00271 Helsinki
- Finland 4 , 00271 Helsinki
| | - Minna Laine
- Department of Pediatric Neurology, Helsinki University Hospital and University of Helsinki 9 , 00029 Helsinki , Finland
| | - Risto Lapatto
- Children's Hospital, University of Helsinki and Helsinki University Central Hospital 10 , 00029 Helsinki , Finland
| | - Päivi Myllynen
- Department of Clinical Chemistry, Cancer and Translational Medicine Research Unit, Medical Research Center, University of Oulu and Northern Finland Laboratory Centre NordLab, Oulu University Hospital 11 , 90029 Oulu , Finland
| | - Harri Niinikoski
- Research Centre for Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku 12 , 20014 Turku , Finland
- Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku 13 , 20014 Turku , Finland
- Centre for Population Health Research, University of Turku and Turku University Hospital 14 , 20014 Turku , Finland
- Department of Pediatrics, Turku University Hospital 15 , 20014 Turku , Finland
| | - Elisa Rahikkala
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
- Department of Clinical Genetics, Oulu University Hospital 16 , 90029 Oulu , Finland
| | - Anu Suomalainen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- HUS Diagnostics, Helsinki University Hospital 17 , 00014 Helsinki , Finland
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen 18 , D-35392 Giessen , Germany
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki 19 , 00014 Helsinki , Finland
| | - Päivi Vieira
- Children and Adolescents, Oulu University Hospital 1 , 90029 Oulu , Finland
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
| | - Tomas Zarybnicky
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- Helsinki Institute of Life Science, University of Helsinki 20 , 00014 Helsinki , Finland
| | - Petra Sipilä
- Research Centre for Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku 12 , 20014 Turku , Finland
- Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku 21 , 20014 Turku , Finland
| | - Satu Kuure
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki 8 , 00014 Helsinki , Finland
- GM-Unit, Laboratory Animal Center, Helsinki Institute of Life Science, University of Helsinki 22 , 00014 Helsinki , Finland
| | - Reetta Hinttala
- Research Unit of Clinical Medicine and Medical Research Center, Oulu University Hospital and University of Oulu 2 , 90014 Oulu , Finland
- Biocenter Oulu, University of Oulu 5 , 90014 Oulu , Finland
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Metrics of progression and prognosis in untreated adults with thymidine kinase 2 deficiency: An observational study. Neuromuscul Disord 2022; 32:728-735. [PMID: 35907766 DOI: 10.1016/j.nmd.2022.07.399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/23/2022] [Accepted: 07/13/2022] [Indexed: 11/21/2022]
Abstract
This historical cohort study evaluated clinical characteristics of progression and prognosis in adults with thymidine kinase 2 deficiency (TK2d). Records were available for 17 untreated adults with TK2d (mean age of onset, 32 years), including longitudinal data from 6 patients (mean follow-up duration, 26.5 months). Pearson's correlation assessed associations between standard motor and respiratory assessments, clinical characteristics, and laboratory values. Longitudinal data were assessed by linear regression mixed models. Respiratory involvement progressed at an annual rate of 8.16% decrement in forced vital capacity (FVC). Most patients under noninvasive ventilation (NIV) remained ambulant (12/14, 86%), reduced FVC was not associated with concomitant decline in 6-minute walk test (6MWT), and 6MWT results were not correlated with FVC. Disease severity, assessed by age at NIV onset, correlated most strongly at diagnosis with: creatinine levels (r = 0.8036; P = 0.0009), followed by FVC (r = 0.7265; P = 0.0033), mtDNA levels in muscle (r = 0.7933; P = 0.0188), and age at disease onset (r = 0.7128; P = 0.0042). This population of adults with TK2d demonstrates rapid deterioration of respiratory muscles, which progresses independently of motor impairment. The results support FVC at diagnosis, mtDNA levels in muscle, and age at disease onset as prognostic indicators. Creatinine levels may also be potentially prognostic, as previously reported in other neuromuscular disorders.
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Gene Therapy for Mitochondrial Diseases: Current Status and Future Perspective. Pharmaceutics 2022; 14:pharmaceutics14061287. [PMID: 35745859 PMCID: PMC9231068 DOI: 10.3390/pharmaceutics14061287] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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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9
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Hanaford AR, Cho YJ, Nakai H. AAV-vector based gene therapy for mitochondrial disease: progress and future perspectives. Orphanet J Rare Dis 2022; 17:217. [PMID: 35668433 PMCID: PMC9169410 DOI: 10.1186/s13023-022-02324-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 04/09/2022] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial diseases are a group of rare, heterogeneous diseases caused by gene mutations in both nuclear and mitochondrial genomes that result in defects in mitochondrial function. They are responsible for significant morbidity and mortality as they affect multiple organ systems and particularly those with high energy-utilizing tissues, such as the nervous system, skeletal muscle, and cardiac muscle. Virtually no effective treatments exist for these patients, despite the urgent need. As the majority of these conditions are monogenic and caused by mutations in nuclear genes, gene replacement is a highly attractive therapeutic strategy. Adeno-associated virus (AAV) is a well-characterized gene replacement vector, and its safety profile and ability to transduce quiescent cells nominates it as a potential gene therapy vehicle for several mitochondrial diseases. Indeed, AAV vector-based gene replacement is currently being explored in clinical trials for one mitochondrial disease (Leber hereditary optic neuropathy) and preclinical studies have been published investigating this strategy in other mitochondrial diseases. This review summarizes the preclinical findings of AAV vector-based gene replacement therapy for mitochondrial diseases including Leigh syndrome, Barth syndrome, ethylmalonic encephalopathy, and others.
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Affiliation(s)
- Allison R Hanaford
- Center for Integrative Brain Research, Seattle Children's Reserach Institute, Seattle, WA, 98101, USA.
- Papé Family Pediatric Research Institute, Oregon Health and Science University, Portland, OR, 97239, USA.
| | - Yoon-Jae Cho
- Papé Family Pediatric Research Institute, Oregon Health and Science University, Portland, OR, 97239, USA
- Division of Pediatric Neurology, Doernbecher Children's Hospital, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR, 97239, USA
- Knight Cancer Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Hiroyuki Nakai
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, 97239, USA
- Department of Molecular Immunology and Microbiology, Oregon Health and Science University, Portland, OR, 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
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10
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232nd ENMC International Workshop: Recommendations for treatment of mitochondrial DNA maintenance disorders. 16 – 18 June 2017, Heemskerk, The Netherlands. Neuromuscul Disord 2022; 32:609-620. [DOI: 10.1016/j.nmd.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/24/2022]
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11
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Berardo A, Engelstad K, Hirano M. Advances in Thymidine Kinase 2 Deficiency: Clinical Aspects, Translational Progress, and Emerging Therapies. J Neuromuscul Dis 2022; 9:225-235. [PMID: 35094997 PMCID: PMC9028656 DOI: 10.3233/jnd-210786] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Defects in the replication, maintenance, and repair of mitochondrial DNA (mtDNA) constitute a growing and genetically heterogeneous group of mitochondrial disorders. Multiple genes participate in these processes, including thymidine kinase 2 (TK2) encoding the mitochondrial matrix protein TK2, a critical component of the mitochondrial nucleotide salvage pathway. TK2 deficiency (TK2d) causes mtDNA depletion, multiple deletions, or both, which manifest predominantly as mitochondrial myopathy. A wide clinical spectrum phenotype includes a severe, rapidly progressive, early onset form (median survival: < 2 years); a less severe childhood-onset form; and a late-onset form with a variably slower rate of progression. Clinical presentation typically includes progressive weakness of limb, neck, facial, oropharyngeal, and respiratory muscle, whereas limb myopathy with ptosis, ophthalmoparesis, and respiratory involvement is more common in the late-onset form. Deoxynucleoside monophosphates and deoxynucleosides that can bypass the TK2 enzyme defect have been assessed in a mouse model, as well as under open-label compassionate use (expanded access) in TK2d patients, indicating clinical efficacy with a favorable side-effect profile. This treatment is currently undergoing testing in clinical trials intended to support approval in the US and European Union (EU). In the early expanded access program, growth differentiation factor 15 (GDF-15) appears to be a useful biomarker that correlates with therapeutic response. With the advent of a specific treatment and given the high morbidity and mortality associated with TK2d, clinicians need to know how to recognize and diagnose this disorder. Here, we summarize translational research about this rare condition emphasizing clinical aspects.
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Affiliation(s)
- Andres Berardo
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
| | - Kristin Engelstad
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
| | - Michio Hirano
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA
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12
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Domínguez-González C, Madruga-Garrido M, Hirano M, Martí I, Martín MA, Munell F, Nascimento A, Olivé M, Quan J, Sardina MD, Martí R, Paradas C. Collaborative model for diagnosis and treatment of very rare diseases: experience in Spain with thymidine kinase 2 deficiency. Orphanet J Rare Dis 2021; 16:407. [PMID: 34600563 PMCID: PMC8487573 DOI: 10.1186/s13023-021-02030-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 09/18/2021] [Indexed: 11/22/2022] Open
Abstract
Background Mitochondrial diseases are difficult to diagnose and treat. Recent advances in genetic diagnostics and more effective treatment options can improve patient diagnosis and prognosis, but patients with mitochondrial disease typically experience delays in diagnosis and treatment. Here, we describe a unique collaborative practice model among physicians and scientists in Spain focused on identifying TK2 deficiency (TK2d), an ultra-rare mitochondrial DNA depletion and deletions syndrome.
Main Body This collaboration spans research and clinical care, including laboratory scientists, adult and pediatric neuromuscular clinicians, geneticists, and pathologists, and has resulted in diagnosis and consolidation of care for patients with TK2d. The incidence of TK2d is not known; however, the first clinical cases of TK2d were reported in 2001, and only ~ 107 unique cases had been reported as of 2018. This unique collaboration in Spain has led to the diagnosis of more than 30 patients with genetically confirmed TK2d across different regions of the country. Research affiliate centers have led investigative treatment with nucleosides based on understanding of TK2d clinical manifestations and disease mechanisms, which resulted in successful treatment of a TK2d mouse model with nucleotide therapy in 2010. Only 1 year later, this collaboration enabled rapid adoption of treatment with pyrimidine nucleotides (and later, nucleosides) under compassionate use. Success in TK2d diagnosis and treatment in Spain is attributable to two important factors: Spain’s fully public national healthcare system, and the designation in 2015 of major National Reference Centers for Neuromuscular Disorders (CSURs). CSUR networking and dissemination facilitated development of a collaborative care network for TK2d disease, wherein participants share information and protocols to request approval from the Ministry of Health to initiate nucleoside therapy. Data have recently been collected in a retrospective study conducted under a Good Clinical Practice–compliant protocol to support development of a new therapeutic approach for TK2d, a progressive disease with no approved therapies. Conclusions The Spanish experience in diagnosis and treatment of TK2d is a model for the diagnosis and development of new treatments for very rare diseases within an existing healthcare system.
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Affiliation(s)
- Cristina Domínguez-González
- Neuromuscular Disorders Unit, Neurology Department, Hospital 12 de Octubre, Madrid, Spain.,Instituto de Investigación imas12, Hospital 12 de Octubre, Madrid, Spain.,Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Michio Hirano
- Neurology Department, H. Houston Merritt Center, Columbia University Irving Medical Center, New York, NY, USA
| | - Itxaso Martí
- Pediatric Department, Donostia University Hospital, Biodonostia Health Research Institute, University of the Basque Country, San Sebastián, Spain
| | - Miguel A Martín
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Mitochondrial Diseases Laboratory, Department of Biochemistry, Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Francina Munell
- Pediatric Department, Vall d'Hebron Hospital, Barcelona, Spain
| | - Andrés Nascimento
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Pediatric Department, Vall d'Hebron Hospital, Barcelona, Spain.,Neuromuscular Unit, Neurology Department, Sant Joan de Déu Research Institute, Sant Joan de Déu Hospital, Barcelona, Spain
| | - Montse Olivé
- Neuromuscular Disorders Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau/Center for Biomedical Network Research On Rare Diseases (CIBERER), Barcelona, Spain
| | | | - M Dolores Sardina
- Pediatric Neurology Department, Badajoz Hospital Complex, Badajoz, Spain
| | - Ramon Martí
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Research Group On Neuromuscular and Mitochondrial Diseases, Vall d'Hebron Research Institute, Autonomous University of Barcelona, Barcelona, Spain
| | - Carmen Paradas
- Neurology Department, Neuromuscular Disorders Unit, Instituto de Biomedicina de Sevilla, Hospital U. Virgen del Rocío, CSIC, Universidad de Sevilla, Avd. Manuel Siurot s/n, 41013, Sevilla, Spain. .,Center for Biomedical Network Research On Neurodegenerative Disorders (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
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Lopez-Gomez C, Sanchez-Quintero MJ, Lee EJ, Kleiner G, Tadesse S, Xie J, Akman HO, Gao G, Hirano M. Synergistic Deoxynucleoside and Gene Therapies for Thymidine Kinase 2 Deficiency. Ann Neurol 2021; 90:640-652. [PMID: 34338329 PMCID: PMC9307066 DOI: 10.1002/ana.26185] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 07/30/2021] [Accepted: 07/31/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Autosomal recessive human thymidine kinase 2 (TK2) mutations cause TK2 deficiency, which typically manifests as a progressive and fatal mitochondrial myopathy in infants and children. Treatment with pyrimidine deoxynucleosides deoxycytidine and thymidine ameliorates mitochondrial defects and extends the lifespan of Tk2 knock-in mouse (Tk2KI ) and compassionate use deoxynucleoside therapy in TK2 deficient patients have shown promising indications of efficacy. To augment therapy for Tk2 deficiency, we assessed gene therapy alone and in combination with deoxynucleoside therapy in Tk2KI mice. METHODS We generated pAAVsc CB6 PI vectors containing human TK2 cDNA (TK2). Adeno-associated virus (AAV)-TK2 was administered to Tk2KI , which were serially assessed for weight, motor functions, and survival as well as biochemical functions in tissues. AAV-TK2 treated mice were further treated with deoxynucleosides. RESULTS AAV9 delivery of human TK2 cDNA to Tk2KI mice efficiently rescued Tk2 activity in all the tissues tested except the kidneys, delayed disease onset, and increased lifespan. Sequential treatment of Tk2KI mice with AAV9 first followed by AAV2 at different ages allowed us to reduce the viral dose while further prolonging the lifespan. Furthermore, addition of deoxycytidine and deoxythymidine supplementation to AAV9 + AAV2 treated Tk2KI mice dramatically improved mtDNA copy numbers in the liver and kidneys, animal growth, and lifespan. INTERPRETATION Our data indicate that AAV-TK2 gene therapy as well as combination deoxynucleoside and gene therapies is more effective in Tk2KI mice than pharmacological alone. Thus, combination of gene therapy with substrate enhancement is a promising therapeutic approach for TK2 deficiency and potentially other metabolic disorders. ANN NEUROL 2021.
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Affiliation(s)
- Carlos Lopez-Gomez
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY.,Unidad de Gestión Clínica de Aparato Digestivo, Hospital Universitario Virgen de la Victoria/Instituto de Investigación Biomédica de Málaga-IBIMA, Málaga, Spain
| | - Maria J Sanchez-Quintero
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY.,Area del Corazón. Hospital Clínico Universitario Virgen de la Victoria, CIBERCV. Instituto de Investigación Biomédica de Málaga-IBIMA. UMA, Málaga, Spain
| | - Eung Jeon Lee
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY
| | - Gulio Kleiner
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY
| | - Saba Tadesse
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY
| | - Jun Xie
- Microbiology and Physiological Systems, University of Massachusetts Medical Center, Worcester, MA.,Horae Gene Therapy Center, University of Massachusetts Medical Center, Worcester, MA
| | - Hasan Orhan Akman
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY
| | - Guangping Gao
- Microbiology and Physiological Systems, University of Massachusetts Medical Center, Worcester, MA.,Horae Gene Therapy Center, University of Massachusetts Medical Center, Worcester, MA
| | - Michio Hirano
- H. Houston Merritt Neuromuscular Research Center, Department of Neurology, Columbia University Irving Medical Center, New York, NY
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Chen JY, Chen HJ, Chen PF. Association of expression and genotypes of thymidylate synthase in non-small cell lung cancer patients with different clinicopathological characteristics. Pteridines 2021. [DOI: 10.1515/pteridines-2020-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Abstract
Objective
To explore the expression and genotypes of thymidylate synthase (TS) in patients of non-small cell lung cancer (NSCLC) with different clinicopathological characteristics.
Methods
The expression profiles of TS were examined by immunohistochemical staining and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) in 160 patients with NSCLC. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect TS-5′UTR tandem repeats, G/C nucleotide polymorphisms, and 3′UTR 6 bp deletion/insertion polymorphisms. The relationships between clinicopathological characteristics and TS expression or genotypes were investigated through χ
2 test. Kaplan–Meier survival analysis was used to analyze the association between TS expression and overall survival (OS) and disease-free survival (DFS) of NSCLC patients.
Results
The expression levels of TS protein and TS gene in NSCLC tissues were significantly higher than that in paracancerous tissues (P < 0.05). Furthermore, high expression of TS protein and 5′UTR polymorphism of TS gene showed significant correlation with differentiation, TNM stage, and lymph node metastases. The frequency of −6 bp/−6 bp genotypes in patients with NSCLC was 43.13% (69/160), which was higher than others. In addition, the rate of TS protein overexpression in NSCLC patients with 3R/3R was 79.79%, which was higher than others. Interestingly, high expression of TS protein predicted shorter DFS and OS and lower 3-year DFS rate and 3-year OS rate.
Conclusions
The expression levels of TS in NSCLC were significantly increased and may help to predict the prognosis of NSCLC, and high expression of TS protein and 5′UTR polymorphism of TS gene were significantly related to differentiation, TNM stage, and lymph node metastases.
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Affiliation(s)
- Jin-Yin Chen
- Department of Respiratory Medicine, Zhuji Affiliated Hospital of Wenzhou Medical University (Zhuji People’s Hospital of Zhejiang Province), 9 Jianmin Street, Taozhu Sub-district, Zhuji , Zhejiang 311800 , China
| | - He-Jian Chen
- Department of Respiratory Medicine, Zhuji Affiliated Hospital of Wenzhou Medical University (Zhuji People’s Hospital of Zhejiang Province), 9 Jianmin Street, Taozhu Sub-district, Zhuji , Zhejiang 311800 , China
| | - Pei-Feng Chen
- Department of Respiratory Medicine, Zhuji Affiliated Hospital of Wenzhou Medical University (Zhuji People’s Hospital of Zhejiang Province), 9 Jianmin Street, Taozhu Sub-district, Zhuji , Zhejiang 311800 , China
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Ramón J, Vila-Julià F, Molina-Granada D, Molina-Berenguer M, Melià MJ, García-Arumí E, Torres-Torronteras J, Cámara Y, Martí R. Therapy Prospects for Mitochondrial DNA Maintenance Disorders. Int J Mol Sci 2021; 22:6447. [PMID: 34208592 PMCID: PMC8234938 DOI: 10.3390/ijms22126447] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial DNA depletion and multiple deletions syndromes (MDDS) constitute a group of mitochondrial diseases defined by dysfunctional mitochondrial DNA (mtDNA) replication and maintenance. As is the case for many other mitochondrial diseases, the options for the treatment of these disorders are rather limited today. Some aggressive treatments such as liver transplantation or allogeneic stem cell transplantation are among the few available options for patients with some forms of MDDS. However, in recent years, significant advances in our knowledge of the biochemical pathomechanisms accounting for dysfunctional mtDNA replication have been achieved, which has opened new prospects for the treatment of these often fatal diseases. Current strategies under investigation to treat MDDS range from small molecule substrate enhancement approaches to more complex treatments, such as lentiviral or adenoassociated vector-mediated gene therapy. Some of these experimental therapies have already reached the clinical phase with very promising results, however, they are hampered by the fact that these are all rare disorders and so the patient recruitment potential for clinical trials is very limited.
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Affiliation(s)
- Javier Ramón
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ferran Vila-Julià
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Miguel Molina-Berenguer
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Maria Jesús Melià
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Elena García-Arumí
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
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Hirano M, Berardo A, Barca E, Emmanuele V, Quinzii C, Simpson CV, Engelstad K, Rosales XQ, Thompson JLP. Regulatory environment for novel therapeutic development in mitochondrial diseases. J Inherit Metab Dis 2021; 44:292-300. [PMID: 33368420 PMCID: PMC9326497 DOI: 10.1002/jimd.12353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/17/2020] [Accepted: 12/22/2020] [Indexed: 11/11/2022]
Abstract
At present, there is just one approved therapy for patients with mitochondrial diseases in Europe, another in Japan, and none in the United States. These facts reveal an important and significant unmet need for approved therapies for these debilitating and often fatal disorders. To fill this need, it is critical for clinicians and drug developers to work closely with regulatory agencies. In the United States, mitochondrial disease patients and clinicians, the United Mitochondrial Disease Foundation, and pharmaceutical industry members have engaged with the Food and Drug Administration to educate each other about these complex and heterogeneous diseases and about regulatory requirements to obtain approvals for novel therapies. Clinical development of therapies for rare diseases has been facilitated by the 1983 US Orphan Drug Act (ODA) and similar legislation in Japan and the European Union. Further legislation and regulatory guidance have expanded and refined regulatory flexibility. While regulatory and financial incentives of the ODA have augmented involvement of pharmaceutical companies, clinicians, with patient advocacy groups and industry, need to conduct natural history studies, develop clinical outcome measures, and identify potential supportive surrogate endpoints predictive of clinical benefit, which together are critical foundations for clinical trials. Thus, the regulatory environment for novel therapeutic development is conducive and offers flexibility for mitochondrial diseases. Nevertheless, flexibility does not mean lower standards, as well-controlled rigorous clinical trials of high quality are still required to establish the efficacy of potential therapies and to obtain regulatory agency approvals for their commercial use. This process is illustrated through the authors' ongoing efforts to develop therapy for thymidine kinase 2 deficiency.
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Affiliation(s)
- Michio Hirano
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | - Andres Berardo
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | - Emanuele Barca
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | - Valentina Emmanuele
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | - Catarina Quinzii
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | | | - Kristin Engelstad
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | - Xiomara Q. Rosales
- Department of Neurology, Columbia University Irving Medical Center, New York, New York
| | - John L. P. Thompson
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York
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17
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Thompson PW. Developing new treatments in partnership for primary mitochondrial disease: What does industry need from academics, and what do academics need from industry? J Inherit Metab Dis 2021; 44:301-311. [PMID: 33141457 DOI: 10.1002/jimd.12326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 10/23/2020] [Accepted: 10/28/2020] [Indexed: 12/11/2022]
Abstract
Developing novel therapeutics for primary mitochondrial disease is likely to require significant academia-industry collaboration. Translational assessments, a tool often used in industry at target validation stage, can highlight disease specific development challenges which requires focused collaborative effort. For PMD, definition of pivotal trial populations and primary endpoints is challenging given lack of clinical precedence, high numbers of subgroups with overlapping symptoms despite common genetics. Disease pathophysiology has not been systematically assessed simultaneously with outcomes in available natural history studies, resulting in a lack of pathophysiology biomarker utilization in clinical trials. Preclinical model systems are available to assist drug development efforts, although these may require better standardization and access. Multistakeholder precompetitive efforts have been used to progress disease pathophysiology biomarker and confirmatory clinical trial endpoint readiness in neurological disease with limited treatment options, such as rare familial Parkinson's disease. This type of approach may be beneficial for PMD therapeutic development, although requires significant funding and time, supported by industry and other funding bodies. Industry expertise on chemistry, data quality and drug development know-how is available to support academic drug development efforts. A combination of industry mindset-reduction of uncertainty to provide an indication statement supportable by evidence-together with academic approach-question-based studies to understand disease mechanisms and patients-has great potential to deliver novel PMD therapeutics.
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Affiliation(s)
- Paul W Thompson
- Mission Therapeutics, Babraham Research Campus, Cambridge, UK
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18
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Abstract
PURPOSE OF REVIEW Although mitochondrial diseases impose a significant functional limitation in the lives of patients, treatment of these conditions has been limited to dietary supplements, exercise, and physical therapy. In the past few years, however, translational medicine has identified potential therapies for these patients. RECENT FINDINGS For patients with primary mitochondrial myopathies, preliminary phase I and II multicenter clinical trials of elamipretide indicate safety and suggest improvement in 6-min walk test (6MWT) performance and fatigue scales. In addition, for thymidine kinase 2-deficient (TK2d) myopathy, compassionate-use oral administration of pyrimidine deoxynucleosides have shown preliminary evidence of safety and efficacy in survival of early onset patients and motor functions relative to historical TK2d controls. SUMMARY The prospects of effective therapies that improve the quality of life for patients with mitochondrial myopathy underscore the necessity for definitive diagnoses natural history studies for better understanding of the diseases.
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Wang L, Sun R, Eriksson S. Basic biochemical characterization of cytosolic enzymes in thymidine nucleotide synthesis in adult rat tissues: implications for tissue specific mitochondrial DNA depletion and deoxynucleoside-based therapy for TK2-deficiency. BMC Mol Cell Biol 2020; 21:33. [PMID: 32345222 PMCID: PMC7189545 DOI: 10.1186/s12860-020-00272-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Deficiency in thymidine kinase 2 (TK2) or p53 inducible ribonucleotide reductase small subunit (p53R2) is associated with tissue specific mitochondrial DNA (mtDNA) depletion. To understand the mechanisms of the tissue specific mtDNA depletion we systematically studied key enzymes in dTMP synthesis in mitochondrial and cytosolic extracts prepared from adult rat tissues. RESULTS In addition to mitochondrial TK2 a cytosolic isoform of TK2 was characterized, which showed similar substrate specificity to the mitochondrial TK2. Total TK activity was highest in spleen and lowest in skeletal muscle. Thymidylate synthase (TS) was detected in cytosols and its activity was high in spleen but low in other tissues. TS protein levels were high in heart, brain and skeletal muscle, which deviated from TS activity levels. The p53R2 proteins were at similar levels in all tissues except liver where it was ~ 6-fold lower. Our results strongly indicate that mitochondria in most tissues are capable of producing enough dTTP for mtDNA replication via mitochondrial TK2, but skeletal muscle mitochondria do not and are most likely dependent on both the salvage and de novo synthesis pathways. CONCLUSION These results provide important information concerning mechanisms for the tissue dependent variation of dTTP synthesis and explained why deficiency in TK2 or p53R2 leads to skeletal muscle dysfunctions. Furthermore, the presence of a putative cytosolic TK2-like enzyme may provide basic knowledge for the understanding of deoxynucleoside-based therapy for mitochondrial disorders.
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Affiliation(s)
- Liya Wang
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden.
| | - Ren Sun
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
| | - Staffan Eriksson
- Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden
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Dard L, Blanchard W, Hubert C, Lacombe D, Rossignol R. Mitochondrial functions and rare diseases. Mol Aspects Med 2020; 71:100842. [PMID: 32029308 DOI: 10.1016/j.mam.2019.100842] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/26/2019] [Accepted: 12/27/2019] [Indexed: 12/19/2022]
Abstract
Mitochondria are dynamic cellular organelles responsible for a large variety of biochemical processes as energy transduction, REDOX signaling, the biosynthesis of hormones and vitamins, inflammation or cell death execution. Cell biology studies established that 1158 human genes encode proteins localized to mitochondria, as registered in MITOCARTA. Clinical studies showed that a large number of these mitochondrial proteins can be altered in expression and function through genetic, epigenetic or biochemical mechanisms including the interaction with environmental toxics or iatrogenic medicine. As a result, pathogenic mitochondrial genetic and functional defects participate to the onset and the progression of a growing number of rare diseases. In this review we provide an exhaustive survey of the biochemical, genetic and clinical studies that demonstrated the implication of mitochondrial dysfunction in human rare diseases. We discuss the striking diversity of the symptoms caused by mitochondrial dysfunction and the strategies proposed for mitochondrial therapy, including a survey of ongoing clinical trials.
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Affiliation(s)
- L Dard
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CELLOMET, CGFB-146 Rue Léo Saignat, Bordeaux, France
| | - W Blanchard
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CELLOMET, CGFB-146 Rue Léo Saignat, Bordeaux, France
| | - C Hubert
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France
| | - D Lacombe
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CHU de Bordeaux, Service de Génétique Médicale, F-33076, Bordeaux, France
| | - R Rossignol
- Bordeaux University, 33000, Bordeaux, France; INSERM U1211, 33000, Bordeaux, France; CELLOMET, CGFB-146 Rue Léo Saignat, Bordeaux, France.
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Khan S, Ince-Dunn G, Suomalainen A, Elo LL. Integrative omics approaches provide biological and clinical insights: examples from mitochondrial diseases. J Clin Invest 2020; 130:20-28. [PMID: 31895050 PMCID: PMC6934214 DOI: 10.1172/jci129202] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
High-throughput technologies for genomics, transcriptomics, proteomics, and metabolomics, and integrative analysis of these data, enable new, systems-level insights into disease pathogenesis. Mitochondrial diseases are an excellent target for hypothesis-generating omics approaches, as the disease group is mechanistically exceptionally complex. Although the genetic background in mitochondrial diseases is in either the nuclear or the mitochondrial genome, the typical downstream effect is dysfunction of the mitochondrial respiratory chain. However, the clinical manifestations show unprecedented variability, including either systemic or tissue-specific effects across multiple organ systems, with mild to severe symptoms, and occurring at any age. So far, the omics approaches have provided mechanistic understanding of tissue-specificity and potential treatment options for mitochondrial diseases, such as metabolome remodeling. However, no curative treatments exist, suggesting that novel approaches are needed. In this Review, we discuss omics approaches and discoveries with the potential to elucidate mechanisms of and therapies for mitochondrial diseases.
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Affiliation(s)
- Sofia Khan
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Gulayse Ince-Dunn
- Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anu Suomalainen
- Research Programs Unit, Stem Cells and Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Neuroscience Center, HiLife, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, HUSlab, Helsinki, Finland
| | - Laura L. Elo
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
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Bioavailability and cytosolic kinases modulate response to deoxynucleoside therapy in TK2 deficiency. EBioMedicine 2019; 46:356-367. [PMID: 31383553 PMCID: PMC6710986 DOI: 10.1016/j.ebiom.2019.07.037] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/10/2019] [Accepted: 07/15/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND TK2 is a nuclear gene encoding the mitochondrial matrix protein thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial nucleotide salvage pathway. Deficiency of TK2 activity causes mitochondrial DNA (mtDNA) depletion, which in humans manifests predominantly as a mitochondrial myopathy with onset typically in infancy and childhood. We previously showed that oral treatment of the Tk2 H126N knock-in mouse model (Tk2-/-) with the TK2 substrates, deoxycytidine (dCtd) and thymidine (dThd), delayed disease onset and prolonged median survival by 3-fold. Nevertheless, dCtd + dThd treated Tk2-/- mice showed mtDNA depletion in brain as early as postnatal day 13 and in virtually all other tissues at age 29 days. METHODS To enhance mechanistic understanding and efficacy of dCtd + dThd therapy, we studied the bioavailability of dCtd and dThd in various tissues as well as levels of the cytosolic enzymes, TK1 and dCK that convert the deoxynucleosides into dCMP and dTMP. FINDINGS Parenteral treatment relative to oral treatment produced higher levels of dCtd and dThd and improved mtDNA levels in liver and heart, but did not ameliorate molecular defects in brain or prolong survival. Down-regulation of TK1 correlated with temporal- and tissue-specificity of response to dCtd + dThd. Finally, we observed in human infant and adult muscle expression of TK1 and dCK, which account for the long-term efficacy to dCtd + dThd therapy in TK2 deficient patients. INTERPRETATIONS These data indicate that the cytosolic pyrimidine salvage pathway enzymes TK1 and dCK are critical for therapeutic efficacy of deoxynucleoside therapy for Tk2 deficiency. FUND: National Institutes of Health P01HD32062.
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Blázquez-Bermejo C, Molina-Granada D, Vila-Julià F, Jiménez-Heis D, Zhou X, Torres-Torronteras J, Karlsson A, Martí R, Cámara Y. Age-related metabolic changes limit efficacy of deoxynucleoside-based therapy in thymidine kinase 2-deficient mice. EBioMedicine 2019; 46:342-355. [PMID: 31351931 PMCID: PMC6711114 DOI: 10.1016/j.ebiom.2019.07.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/05/2019] [Accepted: 07/15/2019] [Indexed: 01/01/2023] Open
Abstract
Background Thymidine kinase 2 (TK2) catalyses the phosphorylation of deoxythymidine (dThd) and deoxycytidine (dCtd) within mitochondria. TK2 deficiency leads to mtDNA depletion or accumulation of multiple deletions. In patients, TK2 mutations typically manifest as a rapidly progressive myopathy with infantile onset, leading to respiratory insufficiency and encephalopathy in the most severe clinical presentations. TK2-deficient mice develop the most severe form of the disease and die at average postnatal day 16. dThd+dCtd administration delayed disease progression and expanded lifespan of a knockin murine model of the disease. Methods We daily administered TK2 knockout mice (Tk2KO) from postnatal day 4 with equimolar doses of dThd+dCtd, dTMP+dCMP, dThd alone or dCtd alone. We monitored body weight and survival and studied different variables at 12 or 29 days of age. We determined metabolite levels in plasma and target tissues, mtDNA copy number in tissues, and the expression and activities of enzymes with a relevant role in mitochondrial dNTP anabolism or catabolism. Findings dThd+dCtd treatment extended average lifespan of Tk2KO mice from 16 to 34 days, attenuated growth retardation, and rescued mtDNA depletion in skeletal muscle and other target tissues of 12-day-old mice, except in brain. However, the treatment was ineffective in 29-day-old mice that still died prematurely. Bioavailability of dThd and dCtd markedly decreased during mouse development. Activity of enzymes catabolizing dThd and dCtd increased with age in small intestine. Conversely, the activity of the anabolic enzymes decreased in target tissues during mouse development. We also found that administration of dThd alone had the same impact on survival to that of dThd+dCtd, whereas dCtd alone had no influence on lifespan. Interpretation dThd+dCtd treatment recruits alternative cytosolic salvage pathways for dNTP synthesis, suggesting that this therapy would be of benefit for any Tk2 mutation. dThd accounts for the therapeutic effect of the combined treatment in mice. During the first weeks after birth, mice experience marked tissue-specific metabolic regulations and ontogenetic changes in dNTP metabolism-related enzymes that limit therapeutic efficacy to early developmental stages. Fund This study was funded by grants from the Spanish Ministry of Industry, Economy and Competitiveness, the Spanish Instituto de Salud Carlos III, the Fundación Inocente, Inocente, AFM Téléthon and the Generalitat de Catalunya. The disclosed funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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Affiliation(s)
- Cora Blázquez-Bermejo
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Ferran Vila-Julià
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Daniel Jiménez-Heis
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Xiaoshan Zhou
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, 141 86 Stockholm, Sweden
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Anna Karlsson
- Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, 141 86 Stockholm, Sweden
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Disorders, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain; Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
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24
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Domínguez-González C, Madruga-Garrido M, Mavillard F, Garone C, Aguirre-Rodríguez FJ, Donati MA, Kleinsteuber K, Martí I, Martín-Hernández E, Morealejo-Aycinena JP, Munell F, Nascimento A, Kalko SG, Sardina MD, Álvarez Del Vayo C, Serrano O, Long Y, Tu Y, Levin B, Thompson JLP, Engelstad K, Uddin J, Torres-Torronteras J, Jimenez-Mallebrera C, Martí R, Paradas C, Hirano M. Deoxynucleoside Therapy for Thymidine Kinase 2-Deficient Myopathy. Ann Neurol 2019; 86:293-303. [PMID: 31125140 DOI: 10.1002/ana.25506] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Thymidine kinase 2, encoded by the nuclear gene TK2, is required for mitochondrial DNA maintenance. Autosomal recessive TK2 mutations cause depletion and multiple deletions of mtDNA that manifest predominantly as a myopathy usually beginning in childhood and progressing relentlessly. We investigated the safety and efficacy of deoxynucleoside monophosphate and deoxynucleoside therapies. METHODS We administered deoxynucleoside monophosphates and deoxynucleoside to 16 TK2-deficient patients under a compassionate use program. RESULTS In 5 patients with early onset and severe disease, survival and motor functions were better than historically untreated patients. In 11 childhood and adult onset patients, clinical measures stabilized or improved. Three of 8 patients who were nonambulatory at baseline gained the ability to walk on therapy; 4 of 5 patients who required enteric nutrition were able to discontinue feeding tube use; and 1 of 9 patients who required mechanical ventilation became able to breathe independently. In motor functional scales, improvements were observed in the 6-minute walk test performance in 7 of 8 subjects, Egen Klassifikation in 2 of 3, and North Star Ambulatory Assessment in all 5 tested. Baseline elevated serum growth differentiation factor 15 levels decreased with treatment in all 7 patients tested. A side effect observed in 8 of the 16 patients was dose-dependent diarrhea, which did not require withdrawal of treatment. Among 12 other TK2 patients treated with deoxynucleoside, 2 adults developed elevated liver enzymes that normalized following discontinuation of therapy. INTERPRETATION This open-label study indicates favorable side effect profiles and clinical efficacy of deoxynucleoside monophosphate and deoxynucleoside therapies for TK2 deficiency. ANN NEUROL 2019;86:293-303.
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Affiliation(s)
- Cristina Domínguez-González
- Neuromuscular Disorders Unit, Neurology Department, Hospital 12 de Octubre, Madrid, Spain.,Instituto de Investigación i + 12, Hospital 12 de Octubre, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marcos Madruga-Garrido
- Neuromuscular Disorders Unit, Pediatric Neurology Department, Instituto de Biomedicina de Sevilla, Hospital U. Virgen del Rocío, Consejo Superior de Investigaciones Científicas, University of Seville, Seville, Spain
| | - Fabiola Mavillard
- Neuromuscular Disorders Unit, Neurology Department, Instituto de Biomedicina de Sevilla, Hospital U. Virgen del Rocío, Consejo Superior de Investigaciones Científicas, University of Seville, Seville, Spain.,Center for Biomedical Network Research on Neurodegenerative Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Caterina Garone
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, UK
| | | | - M Alice Donati
- Metabolic and Neuromuscular Unit, Meyer Hospital, Florence, Italy
| | - Karin Kleinsteuber
- Pediatric Neurology Department, Faculty of Medicine, University of Chile, Las Condes Clinic, Santiago, Chile
| | - Itxaso Martí
- Pediatric Neurology Department, Donostia University Hospital, San Sebastian, Spain
| | - Elena Martín-Hernández
- Instituto de Investigación i + 12, Hospital 12 de Octubre, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Hereditary Metabolic and Mitochondrial Disorders Unit, Pediatric Department, October 12 Hospital, Madrid, Spain
| | | | - Francina Munell
- Pediatric Department, Vall d'Hebron Hospital, Barcelona, Spain
| | - Andrés Nascimento
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Neuromuscular Unit, Neurology Department, Sant Joan de Déu Research Institute, Sant Joan de Déu Hospital, Barcelona, Spain
| | - Susana G Kalko
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Neuromuscular Unit, Neurology Department, Sant Joan de Déu Research Institute, Sant Joan de Déu Hospital, Barcelona, Spain
| | - M Dolores Sardina
- Pediatric Neurology Department, Badajoz Hospital Complex, Badajoz, Spain
| | - Concepcion Álvarez Del Vayo
- Center for Biomedical Network Research on Neurodegenerative Diseases, Instituto de Salud Carlos III, Madrid, Spain.,Pharmacy Department, Virgin of el Rocío University Hospital, Seville, Spain
| | - Olga Serrano
- Pharmacy Department, October 12 Hospital, Madrid, Spain
| | - Yuelin Long
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY
| | - Yuqi Tu
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY
| | - Bruce Levin
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY
| | - John L P Thompson
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY
| | - Kristen Engelstad
- Neurology Department, H. Houston Merritt Center, Columbia University Medical Center, New York, NY
| | - Jasim Uddin
- Neurology Department, H. Houston Merritt Center, Columbia University Medical Center, New York, NY
| | - Javier Torres-Torronteras
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Research Group on Neuromuscular and Mitochondrial Diseases, Vall d'Hebron Research Institute, Autonomous University of Barcelona, Barcelona, Spain
| | - Cecilia Jimenez-Mallebrera
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Neuromuscular Unit, Neurology Department, Sant Joan de Déu Research Institute, Sant Joan de Déu Hospital, Barcelona, Spain
| | - Ramon Martí
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Research Group on Neuromuscular and Mitochondrial Diseases, Vall d'Hebron Research Institute, Autonomous University of Barcelona, Barcelona, Spain
| | - Carmen Paradas
- Neuromuscular Disorders Unit, Neurology Department, Instituto de Biomedicina de Sevilla, Hospital U. Virgen del Rocío, Consejo Superior de Investigaciones Científicas, University of Seville, Seville, Spain.,Center for Biomedical Network Research on Neurodegenerative Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Michio Hirano
- Neurology Department, H. Houston Merritt Center, Columbia University Medical Center, New York, NY
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25
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Wang L, Zhang L, Sun R, Eriksson S. Negative Cooperative Binding of Thymidine, Ordered Substrate Binding, and Product Release of Human Mitochondrial Thymidine Kinase 2 Explain Its Complex Kinetic Properties and Physiological Functions. ACS OMEGA 2018; 3:8971-8979. [PMID: 31459030 PMCID: PMC6644362 DOI: 10.1021/acsomega.8b01376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/30/2018] [Indexed: 06/10/2023]
Abstract
Mitochondrial thymidine kinase 2 (TK2) catalyzes the phosphorylation of thymidine (dT) and deoxycytidine (dC) and is essential for mitochondrial function in post-mitotic tissues. The phosphorylation of dT shows negative cooperativity, but the phosphorylation of dC follows classical Michaelis-Menten kinetics. The enzyme is feedback-inhibited by its end products deoxythymidine triphosphate (dTTP) and deoxycytidine triphosphate (dCTP). In order to better understand the reaction mechanism and the negative cooperative behavior, we conducted isothermal titration calorimetry (ITC) and intrinsic tryptophan fluorescence (ITF) quenching studies with purified recombinant human TK2. Cooperative binding was observed with dT but not dC by the ITC analysis in accordance with earlier enzyme kinetic studies. The phosphate donor adenosine triphosphate (ATP) did not bind to either dTTP-bound or dTTP-free enzymes but bound tightly to the dT- or dC-TK2 complexes with large differences in enthalpy and entropy changes, strongly suggesting an ordered binding of the substrates and different conformational states of the ATP and dT- and dC-TK2 ternary complexes. dTTP binding was endothermic; however, dCTP could not be shown to interact with the enzyme. ITF quenching studies also revealed tight binding of dT, dC, deoxythymidine monophosphate, deoxycytidine monophosphate, and dTTP but not adenosine 5'-diphosphate or ATP. These results strongly indicate an ordered sequential binding of the substrates and ordered release of the products as well as different conformational states of the active site of TK2. These results help to explain the different kinetics observed with dT and dC as substrates, which have important implications for TK2 regulation in vivo.
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Affiliation(s)
- Liya Wang
- Department of Anatomy,
Physiology and Biochemistry, Swedish University
of Agricultural Sciences, Box 7011, SE-750 07 Uppsala, Sweden
| | - Li Zhang
- Department of Cell and Molecular Biology, Uppsala University, The Biomedical Centre, Box 590, SE-751 23 Uppsala, Sweden
| | - Ren Sun
- Department of Immunology, Genetics and
Pathology, Uppsala University, The Rudbeck
Laboratory, SE-751 85 Uppsala, Sweden
| | - Staffan Eriksson
- Department of Anatomy,
Physiology and Biochemistry, Swedish University
of Agricultural Sciences, Box 7011, SE-750 07 Uppsala, Sweden
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26
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Kapnick SM, Pacheco SE, McGuire PJ. The emerging role of immune dysfunction in mitochondrial diseases as a paradigm for understanding immunometabolism. Metabolism 2018; 81:97-112. [PMID: 29162500 PMCID: PMC5866745 DOI: 10.1016/j.metabol.2017.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/07/2017] [Accepted: 11/11/2017] [Indexed: 01/08/2023]
Abstract
Immunometabolism aims to define the role of intermediary metabolism in immune cell function, with bioenergetics and the mitochondria recently taking center stage. To date, the medical literature on mitochondria and immune function extols the virtues of mouse models in exploring this biologic intersection. While the laboratory mouse has become a standard for studying mammalian biology, this model comprises part of a comprehensive approach. Humans, with their broad array of inherited phenotypes, serve as a starting point for studying immunometabolism; specifically, patients with mitochondrial disease. Using this top-down approach, the mouse as a model organism facilitates further exploration of the consequences of mutations involved in mitochondrial maintenance and function. In this review, we will discuss the emerging phenotype of immune dysfunction in mitochondrial disease as a model for understanding the role of the mitochondria in immune function in available mouse models.
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Affiliation(s)
- Senta M Kapnick
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Susan E Pacheco
- Department of Pediatrics, The University of Texas Health Science Center, Houston, TX, USA
| | - Peter J McGuire
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
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27
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Siegmund SE, Yang H, Sharma R, Javors M, Skinner O, Mootha V, Hirano M, Schon EA. Low-dose rapamycin extends lifespan in a mouse model of mtDNA depletion syndrome. Hum Mol Genet 2017; 26:4588-4605. [PMID: 28973153 PMCID: PMC5886265 DOI: 10.1093/hmg/ddx341] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/31/2017] [Accepted: 08/24/2017] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial disorders affecting oxidative phosphorylation (OxPhos) are caused by mutations in both the nuclear and mitochondrial genomes. One promising candidate for treatment is the drug rapamycin, which has been shown to extend lifespan in multiple animal models, and which was previously shown to ameliorate mitochondrial disease in a knock-out mouse model lacking a nuclear-encoded gene specifying an OxPhos structural subunit (Ndufs4). In that model, relatively high-dose intraperitoneal rapamycin extended lifespan and improved markers of neurological disease, via an unknown mechanism. Here, we administered low-dose oral rapamycin to a knock-in (KI) mouse model of authentic mtDNA disease, specifically, progressive mtDNA depletion syndrome, resulting from a mutation in the mitochondrial nucleotide salvage enzyme thymidine kinase 2 (TK2). Importantly, low-dose oral rapamycin was sufficient to extend Tk2KI/KI mouse lifespan significantly, and did so in the absence of detectable improvements in mitochondrial dysfunction. We found no evidence that rapamycin increased survival by acting through canonical pathways, including mitochondrial autophagy. However, transcriptomics and metabolomics analyses uncovered systemic metabolic changes pointing to a potential 'rapamycin metabolic signature.' These changes also implied that rapamycin may have enabled the Tk2KI/KI mice to utilize alternative energy reserves, and possibly triggered indirect signaling events that modified mortality through developmental reprogramming. From a therapeutic standpoint, our results support the possibility that low-dose rapamycin, while not targeting the underlying mtDNA defect, could represent a crucial therapy for the treatment of mtDNA-driven, and some nuclear DNA-driven, mitochondrial diseases.
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Affiliation(s)
| | | | - Rohit Sharma
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Martin Javors
- Department of Psychiatry, University of Texas, San Antonio, TX 78229, USA
| | - Owen Skinner
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Vamsi Mootha
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | - Eric A Schon
- Department of Neurology
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
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28
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Lopez-Gomez C, Levy RJ, Sanchez-Quintero MJ, Juanola-Falgarona M, Barca E, Garcia-Diaz B, Tadesse S, Garone C, Hirano M. Deoxycytidine and Deoxythymidine Treatment for Thymidine Kinase 2 Deficiency. Ann Neurol 2017; 81:641-652. [PMID: 28318037 DOI: 10.1002/ana.24922] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/09/2017] [Accepted: 03/09/2017] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene, TK2, cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, deoxycytidine monophosphate (dCMP) and deoxythymidine monophosphate (dTMP), prolongs the life span of Tk2-deficient (Tk2-/- ) mice by 2- to 3-fold. Because we observed rapid catabolism of the deoxynucleoside monophosphates to deoxythymidine (dT) and deoxycytidine (dC), we hypothesized that: (1) deoxynucleosides might be the major active agents and (2) inhibition of deoxycytidine deamination might enhance dTMP+dCMP therapy. METHODS To test these hypotheses, we assessed two therapies in Tk2-/- mice: (1) dT+dC and (2) coadministration of the deaminase inhibitor, tetrahydrouridine (THU), with dTMP+dCMP. RESULTS We observed that dC+dT delayed disease onset, prolonged life span of Tk2-deficient mice and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased life span of Tk2-/- animals compared to dCMP+dTMP. INTERPRETATION Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. Ann Neurol 2017;81:641-652.
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Affiliation(s)
- Carlos Lopez-Gomez
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY
| | - Rebecca J Levy
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY
| | - Maria J Sanchez-Quintero
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY
| | - Martí Juanola-Falgarona
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY
| | - Emanuele Barca
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY.,Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Beatriz Garcia-Diaz
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY.,Unidad de Gestión Clínica de Neurociencias, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga, Spain
| | - Saba Tadesse
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY
| | - Caterina Garone
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY.,MRC Mitochondrial Biology Unit, Cambridge University, Cambridge, United Kingdom
| | - Michio Hirano
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY
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29
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Wang T, Zhang M, Jiang Z, Seli E. Mitochondrial dysfunction and ovarian aging. Am J Reprod Immunol 2017; 77. [PMID: 28194828 DOI: 10.1111/aji.12651] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/17/2017] [Indexed: 01/02/2023] Open
Abstract
Mitochondria are double-membrane-bound organelles that are responsible for the generation of most of the cell's energy. Mitochondrial dysfunction has been implicated in cellular senescence in general and ovarian aging in particular. Recent studies exploited this association by studying mitochondrial DNA (mtDNA) copy number as a potential biomarker of embryo viability and the use of mitochondrial nutrients and autologous mitochondrial transfer as a potential treatment for poor ovarian function and response.
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Affiliation(s)
- Tianren Wang
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Man Zhang
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Zongliang Jiang
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Emre Seli
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
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30
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Two transgenic mouse models for β-subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations. Biochem J 2016; 473:3463-3485. [PMID: 27496549 PMCID: PMC5126846 DOI: 10.1042/bcj20160594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/05/2016] [Indexed: 12/14/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer enzyme composed of Suclg1 α-subunit and a substrate-specific Sucla2 or Suclg2 β-subunit yielding ATP or GTP, respectively. In humans, the deficiency of this enzyme leads to encephalomyopathy with or without methylmalonyl aciduria, in addition to resulting in mitochondrial DNA depletion. We generated mice lacking either one Sucla2 or Suclg2 allele. Sucla2 heterozygote mice exhibited tissue- and age-dependent decreases in Sucla2 expression associated with decreases in ATP-forming activity, but rebound increases in cardiac Suclg2 expression and GTP-forming activity. Bioenergetic parameters including substrate-level phosphorylation (SLP) were not different between wild-type and Sucla2 heterozygote mice unless a submaximal pharmacological inhibition of SUCL was concomitantly present. mtDNA contents were moderately decreased, but blood carnitine esters were significantly elevated. Suclg2 heterozygote mice exhibited decreases in Suclg2 expression but no rebound increases in Sucla2 expression or changes in bioenergetic parameters. Surprisingly, deletion of one Suclg2 allele in Sucla2 heterozygote mice still led to a rebound but protracted increase in Suclg2 expression, yielding double heterozygote mice with no alterations in GTP-forming activity or SLP, but more pronounced changes in mtDNA content and blood carnitine esters, and an increase in succinate dehydrogenase activity. We conclude that a partial reduction in Sucla2 elicits rebound increases in Suclg2 expression, which is sufficiently dominant to overcome even a concomitant deletion of one Suclg2 allele, pleiotropically affecting metabolic pathways associated with SUCL. These results as well as the availability of the transgenic mouse colonies will be of value in understanding SUCL deficiency.
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31
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Zhang J, Wang C, Chen X, Takada M, Fan C, Zheng X, Wen H, Liu Y, Wang C, Pestell RG, Aird KM, Kaelin WG, Liu XS, Zhang Q. EglN2 associates with the NRF1-PGC1α complex and controls mitochondrial function in breast cancer. EMBO J 2015; 34:2953-70. [PMID: 26492917 DOI: 10.15252/embj.201591437] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 09/11/2015] [Indexed: 12/15/2022] Open
Abstract
The EglN2/PHD1 prolyl hydroxylase is an important oxygen sensor contributing to breast tumorigenesis. Emerging studies suggest that there is functional cross talk between oxygen sensing and mitochondrial function, both of which play an essential role for sustained tumor growth. However, the potential link between EglN2 and mitochondrial function remains largely undefined. Here, we show that EglN2 depletion decreases mitochondrial respiration in breast cancer under normoxia and hypoxia, which correlates with decreased mitochondrial DNA in a HIF1/2α-independent manner. Integrative analyses of gene expression profile and genomewide binding of EglN2 under hypoxic conditions reveal nuclear respiratory factor 1 (NRF1) motif enrichment in EglN2-activated genes, suggesting NRF1 as an EglN2 binding partner. Mechanistically, by forming an activator complex with PGC1α and NRF1 on chromatin, EglN2 promotes the transcription of ferridoxin reductase (FDXR) and maintains mitochondrial function. In addition, FDXR, as one of effectors for EglN2, contributes to breast tumorigenesis in vitro and in vivo. Our findings suggest that EglN2 regulates mitochondrial function in ERα-positive breast cancer.
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Affiliation(s)
- Jing Zhang
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Chengyang Wang
- Department of Bioinformatics, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xi Chen
- Department of Molecular and Cellular Biology, The Lester and Sue Smith Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
| | - Mamoru Takada
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Cheng Fan
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Xingnan Zheng
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Haitao Wen
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA Department of Surgery, University of North Carolina, Chapel Hill, NC, USA
| | - Yong Liu
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Chenguang Wang
- Program of Radiation Protection and Drug Discovery, Institute of Radiation Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin, China
| | - Richard G Pestell
- Department of Cancer Biology and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Katherine M Aird
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA, USA
| | - William G Kaelin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Xiaole Shirley Liu
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard School of Public Health, Boston, MA, USA
| | - Qing Zhang
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, USA
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Ripolone M, Ronchi D, Violano R, Vallejo D, Fagiolari G, Barca E, Lucchini V, Colombo I, Villa L, Berardinelli A, Balottin U, Morandi L, Mora M, Bordoni A, Fortunato F, Corti S, Parisi D, Toscano A, Sciacco M, DiMauro S, Comi GP, Moggio M. Impaired Muscle Mitochondrial Biogenesis and Myogenesis in Spinal Muscular Atrophy. JAMA Neurol 2015; 72:666-75. [PMID: 25844556 PMCID: PMC4944827 DOI: 10.1001/jamaneurol.2015.0178] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
IMPORTANCE The important depletion of mitochondrial DNA (mtDNA) and the general depression of mitochondrial respiratory chain complex levels (including complex II) have been confirmed, implying an increasing paucity of mitochondria in the muscle from patients with types I, II, and III spinal muscular atrophy (SMA-I, -II, and -III, respectively). OBJECTIVE To investigate mitochondrial dysfunction in a large series of muscle biopsy samples from patients with SMA. DESIGN, SETTING, AND PARTICIPANTS We studied quadriceps muscle samples from 24 patients with genetically documented SMA and paraspinal muscle samples from 3 patients with SMA-II undergoing surgery for scoliosis correction. Postmortem muscle samples were obtained from 1 additional patient. Age-matched controls consisted of muscle biopsy specimens from healthy children aged 1 to 3 years who had undergone analysis for suspected myopathy. Analyses were performed at the Neuromuscular Unit, Istituto di Ricovero e Cura a Carattere Scientifico Foundation Ca' Granda Ospedale Maggiore Policlinico-Milano, from April 2011 through January 2015. EXPOSURES We used histochemical, biochemical, and molecular techniques to examine the muscle samples. MAIN OUTCOMES AND MEASURES Respiratory chain activity and mitochondrial content. RESULTS Results of histochemical analysis revealed that cytochrome-c oxidase (COX) deficiency was more evident in muscle samples from patients with SMA-I and SMA-II. Residual activities for complexes I, II, and IV in muscles from patients with SMA-I were 41%, 27%, and 30%, respectively, compared with control samples (P < .005). Muscle mtDNA content and cytrate synthase activity were also reduced in all 3 SMA types (P < .05). We linked these alterations to downregulation of peroxisome proliferator-activated receptor coactivator 1α, the transcriptional activators nuclear respiratory factor 1 and nuclear respiratory factor 2, mitochondrial transcription factor A, and their downstream targets, implying depression of the entire mitochondrial biogenesis. Results of Western blot analysis confirmed the reduced levels of the respiratory chain subunits that included mitochondrially encoded COX1 (47.5%; P = .004), COX2 (32.4%; P < .001), COX4 (26.6%; P < .001), and succinate dehydrogenase complex subunit A (65.8%; P = .03) as well as the structural outer membrane mitochondrial porin (33.1%; P < .001). Conversely, the levels of expression of 3 myogenic regulatory factors-muscle-specific myogenic factor 5, myoblast determination 1, and myogenin-were higher in muscles from patients with SMA compared with muscles from age-matched controls (P < .05). CONCLUSIONS AND RELEVANCE Our results strongly support the conclusion that an altered regulation of myogenesis and a downregulated mitochondrial biogenesis contribute to pathologic change in the muscle of patients with SMA. Therapeutic strategies should aim at counteracting these changes.
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Affiliation(s)
- Michela Ripolone
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Dario Ronchi
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Raffaella Violano
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Dionis Vallejo
- Sien-Servicios Integrales en Neurologia, Universidad de Antioquia, Medellin, Colombia
| | - Gigliola Fagiolari
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Emanuele Barca
- Department of Neurology, Columbia University Medical Center, New York, New York
| | - Valeria Lucchini
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Irene Colombo
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Luisa Villa
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Angela Berardinelli
- Child Neuropsychiatry Unit, C. Mondino National Neurological Institute, Pavia, Italy
| | - Umberto Balottin
- Child Neuropsychiatry Unit, C. Mondino National Neurological Institute, Pavia, Italy
| | - Lucia Morandi
- Neuromuscular Diseases and Neuroimmunology Unit, Department of Clinical Neurosciences, IRCCS Foundation, Carlo Besta Neurological Institute, Milan, Italy
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Department of Clinical Neurosciences, IRCCS Foundation, Carlo Besta Neurological Institute, Milan, Italy
| | - Andreina Bordoni
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Francesco Fortunato
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Stefania Corti
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Daniela Parisi
- Reference Center for Rare Neuromuscular Disorders, Department of Neurosciences, University of Messina, Azienda Ospedaliera Universitaria Policlinico G. Martino, Messina, Italy
| | - Antonio Toscano
- Reference Center for Rare Neuromuscular Disorders, Department of Neurosciences, University of Messina, Azienda Ospedaliera Universitaria Policlinico G. Martino, Messina, Italy
| | - Monica Sciacco
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, New York
| | - Giacomo P Comi
- Neurology Unit, Neuroscience Section, Department of Pathophysiology and Transplantation, Dino Ferrari Centre, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular Unit, Dino Ferrari Centre, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Foundation Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
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Fasullo M, Endres L. Nucleotide salvage deficiencies, DNA damage and neurodegeneration. Int J Mol Sci 2015; 16:9431-49. [PMID: 25923076 PMCID: PMC4463597 DOI: 10.3390/ijms16059431] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/16/2015] [Accepted: 04/03/2015] [Indexed: 12/20/2022] Open
Abstract
Nucleotide balance is critically important not only in replicating cells but also in quiescent cells. This is especially true in the nervous system, where there is a high demand for adenosine triphosphate (ATP) produced from mitochondria. Mitochondria are particularly prone to oxidative stress-associated DNA damage because nucleotide imbalance can lead to mitochondrial depletion due to low replication fidelity. Failure to maintain nucleotide balance due to genetic defects can result in infantile death; however there is great variability in clinical presentation for particular diseases. This review compares genetic diseases that result from defects in specific nucleotide salvage enzymes and a signaling kinase that activates nucleotide salvage after DNA damage exposure. These diseases include Lesch-Nyhan syndrome, mitochondrial depletion syndromes, and ataxia telangiectasia. Although treatment options are available to palliate symptoms of these diseases, there is no cure. The conclusions drawn from this review include the critical role of guanine nucleotides in preventing neurodegeneration, the limitations of animals as disease models, and the need to further understand nucleotide imbalances in treatment regimens. Such knowledge will hopefully guide future studies into clinical therapies for genetic diseases.
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Affiliation(s)
- Michael Fasullo
- Colleges of Nanoscale Sciences and Engineering, State University of New York Polytechnic University, Albany, NY 12203, USA.
| | - Lauren Endres
- Colleges of Nanoscale Sciences and Engineering, State University of New York Polytechnic University, Albany, NY 12203, USA.
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34
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Garone C, Garcia-Diaz B, Emmanuele V, Lopez LC, Tadesse S, Akman HO, Tanji K, Quinzii CM, Hirano M. Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency. EMBO Mol Med 2015; 6:1016-27. [PMID: 24968719 PMCID: PMC4154130 DOI: 10.15252/emmm.201404092] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2(-/-)) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-old Tk2(-/-) mice treated with dCMP+dTMP 200 mg/kg/day each (Tk2(-/-200dCMP/) (dTMP)) demonstrated that in mutant animals, the compounds raise dTTP concentrations, increase levels of mtDNA, ameliorate defects of mitochondrial respiratory chain enzymes, and significantly prolong their lifespan (34 days with treatment versus 13 days untreated). A second trial of dCMP+dTMP each at 400 mg/kg/day showed even greater phenotypic and biochemical improvements. In conclusion, dCMP/dTMP supplementation is the first effective pharmacologic treatment for Tk2 deficiency.
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Affiliation(s)
- Caterina Garone
- Department of Neurology, Columbia University Medical Center, New York, NY, USA Human Genetics Joint PhD Program, University of Bologna and Turin, Turin, Italy
| | - Beatriz Garcia-Diaz
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Valentina Emmanuele
- Department of Neurology, Columbia University Medical Center, New York, NY, USA Pediatric Clinic University of Genoa IRCCS G. Gaslini Institute, Genoa, Italy
| | - Luis C Lopez
- Instituto de Biotecnología, Centro de Investigación Biomédica, Universidad de Granada Parque Tecnológico de Ciencias de la Salud, Armilla, Spain
| | - Saba Tadesse
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Hasan O Akman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Kurenai Tanji
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Catarina M Quinzii
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Michio Hirano
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
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Peralta S, Torraco A, Iommarini L, Diaz F. Mitochondrial Diseases Part III: Therapeutic interventions in mouse models of OXPHOS deficiencies. Mitochondrion 2015; 23:71-80. [PMID: 25638392 DOI: 10.1016/j.mito.2015.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 12/19/2022]
Abstract
Mitochondrial defects are the cause of numerous disorders affecting the oxidative phosphorylation system (OXPHOS) in humans leading predominantly to neurological and muscular degeneration. The molecular origin, manifestations, and progression of mitochondrial diseases have a broad spectrum, which makes very challenging to find a globally effective therapy. The study of the molecular mechanisms underlying the mitochondrial dysfunction indicates that there is a wide range of pathways, enzymes and molecules that can be potentially targeted for therapeutic purposes. Therefore, focusing on the pathology of the disease is essential to design new treatments. In this review, we will summarize and discuss the different therapeutic interventions tested in some mouse models of mitochondrial diseases emphasizing the molecular mechanisms of action and their potential applications.
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Affiliation(s)
- Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40126, Bologna, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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36
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Iommarini L, Peralta S, Torraco A, Diaz F. Mitochondrial Diseases Part II: Mouse models of OXPHOS deficiencies caused by defects in regulatory factors and other components required for mitochondrial function. Mitochondrion 2015; 22:96-118. [PMID: 25640959 DOI: 10.1016/j.mito.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are defined as defects that affect the oxidative phosphorylation system (OXPHOS). They are characterized by a heterogeneous array of clinical presentations due in part to a wide variety of factors required for proper function of the components of the OXPHOS system. There is no cure for these disorders owing to our poor knowledge of the pathogenic mechanisms of disease. To understand the mechanisms of human disease numerous mouse models have been developed in recent years. Here we summarize the features of several mouse models of mitochondrial diseases directly related to those factors affecting mtDNA maintenance, replication, transcription, translation as well as other proteins that are involved in mitochondrial dynamics and quality control which affect mitochondrial OXPHOS function without being intrinsic components of the system. We discuss how these models have contributed to our understanding of mitochondrial diseases and their pathogenic mechanisms.
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Affiliation(s)
- Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40128 Bologna, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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37
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Inhibition of oxidative metabolism leads to p53 genetic inactivation and transformation in neural stem cells. Proc Natl Acad Sci U S A 2015; 112:1059-64. [PMID: 25583481 DOI: 10.1073/pnas.1413165112] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alterations of mitochondrial metabolism and genomic instability have been implicated in tumorigenesis in multiple tissues. High-grade glioma (HGG), one of the most lethal human neoplasms, displays genetic modifications of Krebs cycle components as well as electron transport chain (ETC) alterations. Furthermore, the p53 tumor suppressor, which has emerged as a key regulator of mitochondrial respiration at the expense of glycolysis, is genetically inactivated in a large proportion of HGG cases. Therefore, it is becoming evident that genetic modifications can affect cell metabolism in HGG; however, it is currently unclear whether mitochondrial metabolism alterations could vice versa promote genomic instability as a mechanism for neoplastic transformation. Here, we show that, in neural progenitor/stem cells (NPCs), which can act as HGG cell of origin, inhibition of mitochondrial metabolism leads to p53 genetic inactivation. Impairment of respiration via inhibition of complex I or decreased mitochondrial DNA copy number leads to p53 genetic loss and a glycolytic switch. p53 genetic inactivation in ETC-impaired neural stem cells is caused by increased reactive oxygen species and associated oxidative DNA damage. ETC-impaired cells display a marked growth advantage in the presence or absence of oncogenic RAS, and form undifferentiated tumors when transplanted into the mouse brain. Finally, p53 mutations correlated with alterations in ETC subunit composition and activity in primary glioma-initiating neural stem cells. Together, these findings provide previously unidentified insights into the relationship between mitochondria, genomic stability, and tumor suppressive control, with implications for our understanding of brain cancer pathogenesis.
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38
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Generating Mouse Models of Mitochondrial Disease. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00043-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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39
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Kamath VG, Hsiung CH, Lizenby ZJ, McKee EE. Heart mitochondrial TTP synthesis and the compartmentalization of TMP. J Biol Chem 2014; 290:2034-41. [PMID: 25505243 DOI: 10.1074/jbc.m114.624213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The primary pathway of TTP synthesis in the heart requires thymidine salvage by mitochondrial thymidine kinase 2 (TK2). However, the compartmentalization of this pathway and the transport of thymidine nucleotides are not well understood. We investigated the metabolism of [(3)H]thymidine or [(3)H]TMP as precursors of [(3)H]TTP in isolated intact or broken mitochondria from the rat heart. The results demonstrated that [(3)H]thymidine was readily metabolized by the mitochondrial salvage enzymes to TTP in intact mitochondria. The equivalent addition of [(3)H]TMP produced far less [(3)H]TTP than the amount observed with [(3)H]thymidine as the precursor. Using zidovudine to inhibit TK2, the synthesis of [(3)H]TTP from [(3)H]TMP was effectively blocked, demonstrating that synthesis of [(3)H]TTP from [(3)H]TMP arose solely from the dephosphorysynthase pathway that includes deoxyuridine triphosphatelation of [(3)H]TMP to [(3)H]thymidine. To determine the role of the membrane in TMP metabolism, mitochondrial membranes were disrupted by freezing and thawing. In broken mitochondria, [(3)H]thymidine was readily converted to [(3)H]TMP, but further phosphorylation was prevented even though the energy charge was well maintained by addition of oligomycin A, phosphocreatine, and creatine phosphokinase. The failure to synthesize TTP in broken mitochondria was not related to a loss of membrane potential or inhibition of the electron transport chain, as confirmed by addition of carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone and potassium cyanide, respectively, in intact mitochondria. In summary, these data, taken together, suggest that the thymidine salvage pathway is compartmentalized so that TMP kinase prefers TMP synthesized by TK2 over medium TMP and that this is disrupted in broken mitochondria.
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Affiliation(s)
- Vasudeva G Kamath
- From the Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859
| | - Chia-Heng Hsiung
- From the Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859
| | - Zachary J Lizenby
- From the Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859
| | - Edward E McKee
- From the Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859
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40
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Kanabus M, Heales SJ, Rahman S. Development of pharmacological strategies for mitochondrial disorders. Br J Pharmacol 2014; 171:1798-817. [PMID: 24116962 PMCID: PMC3976606 DOI: 10.1111/bph.12456] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 09/21/2013] [Accepted: 09/26/2013] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial diseases are an unusually genetically and phenotypically heterogeneous group of disorders, which are extremely challenging to treat. Currently, apart from supportive therapy, there are no effective treatments for the vast majority of mitochondrial diseases. Huge scientific effort, however, is being put into understanding the mechanisms underlying mitochondrial disease pathology and developing potential treatments. To date, a variety of treatments have been evaluated by randomized clinical trials, but unfortunately, none of these has delivered breakthrough results. Increased understanding of mitochondrial pathways and the development of many animal models, some of which are accurate phenocopies of human diseases, are facilitating the discovery and evaluation of novel prospective treatments. Targeting reactive oxygen species has been a treatment of interest for many years; however, only in recent years has it been possible to direct antioxidant delivery specifically into the mitochondria. Increasing mitochondrial biogenesis, whether by pharmacological approaches, dietary manipulation or exercise therapy, is also currently an active area of research. Modulating mitochondrial dynamics and mitophagy and the mitochondrial membrane lipid milieu have also emerged as possible treatment strategies. Recent technological advances in gene therapy, including allotopic and transkingdom gene expression and mitochondrially targeted transcription activator-like nucleases, have led to promising results in cell and animal models of mitochondrial diseases, but most of these techniques are still far from clinical application.
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Affiliation(s)
- M Kanabus
- Clinical and Molecular Genetics Unit, UCL Institute of Child Health, London, UK
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Knierim E, Seelow D, Gill E, von Moers A, Schuelke M. Clinical application of whole exome sequencing reveals a novel compound heterozygous TK2-mutation in two brothers with rapidly progressive combined muscle-brain atrophy, axonal neuropathy, and status epilepticus. Mitochondrion 2014; 20:1-6. [PMID: 25446393 DOI: 10.1016/j.mito.2014.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 10/05/2014] [Accepted: 10/29/2014] [Indexed: 10/24/2022]
Abstract
Mutations in several genes cause mtDNA depletion associated with encephalomyopathy. Due to phenotypic overlap, it is difficult to conclude from clinical phenotype to genetic defect. Here we report on two brothers who presented with rapid fatty muscle degeneration, axonal neuropathy, rapid loss of supratentorial white and gray matter, and status epilepticus. Whole exome sequencing coupled with 'identity-by-state' (IBS) analysis revealed a compound heterozygous missense mutation (p.M117V, p.A139V) in the thymidine kinase 2 (TK2) gene that segregated with the phenotype. Both mutations were located in the thymidine binding pouch of the enzyme. Residual mtDNA copy numbers in muscle were 8.5%, but normal in blood and fibroblasts. Our results broaden the clinical phenotype spectrum of TK2 mutations and promote WES as a useful method in the clinical setting for mutation detection, even in untypical cases. If two or more affected siblings from a non-consanguineous family can be investigated, IBS-analysis provides a powerful tool to narrow the number of disease candidates, similarly to autozygosity mapping in consanguineous families.
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Affiliation(s)
- Ellen Knierim
- NeuroCure Clinical Research Center (NCRC), Charité-Universitätsmedizin Berlin, Germany; Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Germany
| | - Dominik Seelow
- NeuroCure Clinical Research Center (NCRC), Charité-Universitätsmedizin Berlin, Germany; Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Germany
| | - Esther Gill
- NeuroCure Clinical Research Center (NCRC), Charité-Universitätsmedizin Berlin, Germany
| | | | - Markus Schuelke
- NeuroCure Clinical Research Center (NCRC), Charité-Universitätsmedizin Berlin, Germany; Department of Neuropediatrics, Charité-Universitätsmedizin Berlin, Germany.
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Zidovudine induces downregulation of mitochondrial deoxynucleoside kinases: implications for mitochondrial toxicity of antiviral nucleoside analogs. Antimicrob Agents Chemother 2014; 58:6758-66. [PMID: 25182642 DOI: 10.1128/aac.03613-14] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mitochondrial thymidine kinase 2 (TK2) and deoxyguanosine kinase (dGK) catalyze the initial phosphorylation of deoxynucleosides in the synthesis of the DNA precursors required for mitochondrial DNA (mtDNA) replication and are essential for mitochondrial function. Antiviral nucleosides are known to cause toxic mitochondrial side effects. Here, we examined the effects of 3'-azido-2',3'-dideoxythymidine (AZT) (zidovudine) on mitochondrial TK2 and dGK levels and found that AZT treatment led to downregulation of mitochondrial TK2 and dGK in U2OS cells, whereas cytosolic deoxycytidine kinase (dCK) and thymidine kinase 1 (TK1) levels were not affected. The AZT effects on mitochondrial TK2 and dGK were similar to those of oxidants (e.g., hydrogen peroxide); therefore, we examined the oxidative effects of AZT. We found a modest increase in cellular reactive oxygen species (ROS) levels in the AZT-treated cells. The addition of uridine to AZT-treated cells reduced ROS levels and protein oxidation and prevented the degradation of mitochondrial TK2 and dGK. In organello studies indicated that the degradation of mitochondrial TK2 and dGK is a mitochondrial event. These results suggest that downregulation of mitochondrial TK2 and dGK may lead to decreased mitochondrial DNA precursor pools and eventually mtDNA depletion, which has significant implications for the regulation of mitochondrial nucleotide biosynthesis and for antiviral therapy using nucleoside analogs.
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Payne BAI, Gardner K, Chinnery PF. Mitochondrial DNA mutations in ageing and disease: implications for HIV? Antivir Ther 2014; 20:109-20. [PMID: 25032944 DOI: 10.3851/imp2824] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2014] [Indexed: 10/25/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations cause neurological and multisystem disease. Somatic (acquired) mtDNA mutations are also associated with degenerative diseases and with normal human ageing. It is well established that certain nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral drugs cause inhibition of the mtDNA polymerase, pol γ, leading to a reduction in mtDNA content (depletion). Given this effect of NRTI therapy on mtDNA replication, it is plausible that NRTI treatment may also lead to increased mtDNA mutations. Here we review recent evidence for an effect of HIV infection or NRTI therapy on mtDNA mutations, as well as discussing the methodological challenges in addressing this question. Finally, we discuss the possible implications for HIV-infected persons, with particular reference to ageing.
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Affiliation(s)
- Brendan A I Payne
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
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Sun R, Eriksson S, Wang L. Down-regulation of mitochondrial thymidine kinase 2 and deoxyguanosine kinase by didanosine: Implication for mitochondrial toxicities of anti-HIV nucleoside analogs. Biochem Biophys Res Commun 2014; 450:1021-6. [DOI: 10.1016/j.bbrc.2014.06.098] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 06/20/2014] [Indexed: 12/14/2022]
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Lee MH, Wang L, Chang ZF. The contribution of mitochondrial thymidylate synthesis in preventing the nuclear genome stress. Nucleic Acids Res 2014; 42:4972-84. [PMID: 24561807 PMCID: PMC4005647 DOI: 10.1093/nar/gku152] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
In quiescent fibroblasts, the expression levels of cytosolic enzymes for thymidine triphosphate (dTTP) synthesis are down-regulated, causing a marked reduction in the dTTP pool. In this study, we provide evidence that mitochondrial thymidylate synthesis via thymidine kinase 2 (TK2) is a limiting factor for the repair of ultraviolet (UV) damage in the nuclear compartment in quiescent fibroblasts. We found that TK2 deficiency causes secondary DNA double-strand breaks formation in the nuclear genome of quiescent cells at the late stage of recovery from UV damage. Despite slower repair of quiescent fibroblast deficient in TK2, DNA damage signals eventually disappeared, and these cells were capable of re-entering the S phase after serum stimulation. However, these cells displayed severe genome stress as revealed by the dramatic increase in 53BP1 nuclear body in the G1 phase of the successive cell cycle. Here, we conclude that mitochondrial thymidylate synthesis via TK2 plays a role in facilitating the quality repair of UV damage for the maintenance of genome integrity in the cells that are temporarily arrested in the quiescent state.
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Affiliation(s)
- Ming-Hsiang Lee
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan (R.O.C.), Department of Anatomy, Physiology and Biochemistry, The Swedish University of Agricultural Sciences, Biomedical Center, S-751 23 Uppsala, Sweden and Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan (R.O.C.)
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Donti TR, Stromberger C, Ge M, Eldin KW, Craigen WJ, Graham BH. Screen for abnormal mitochondrial phenotypes in mouse embryonic stem cells identifies a model for succinyl-CoA ligase deficiency and mtDNA depletion. Dis Model Mech 2014; 7:271-80. [PMID: 24271779 PMCID: PMC3917248 DOI: 10.1242/dmm.013466] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/18/2013] [Indexed: 12/12/2022] Open
Abstract
Mutations in subunits of succinyl-CoA synthetase/ligase (SCS), a component of the citric acid cycle, are associated with mitochondrial encephalomyopathy, elevation of methylmalonic acid (MMA), and mitochondrial DNA (mtDNA) depletion. A FACS-based retroviral-mediated gene trap mutagenesis screen in mouse embryonic stem (ES) cells for abnormal mitochondrial phenotypes identified a gene trap allele of Sucla2 (Sucla2(SAβgeo)), which was used to generate transgenic mice. Sucla2 encodes the ADP-specific β-subunit isoform of SCS. Sucla2(SAβgeo) homozygotes exhibited recessive lethality, with most mutants dying late in gestation (e18.5). Mutant placenta and embryonic (e17.5) brain, heart and muscle showed varying degrees of mtDNA depletion (20-60%). However, there was no mtDNA depletion in mutant liver, where the gene is not normally expressed. Elevated levels of MMA were observed in embryonic brain. SCS-deficient mouse embryonic fibroblasts (MEFs) demonstrated a 50% reduction in mtDNA content compared with wild-type MEFs. The mtDNA depletion resulted in reduced steady state levels of mtDNA encoded proteins and multiple respiratory chain deficiencies. mtDNA content could be restored by reintroduction of Sucla2. This mouse model of SCS deficiency and mtDNA depletion promises to provide insights into the pathogenesis of mitochondrial diseases with mtDNA depletion and into the biology of mtDNA maintenance. In addition, this report demonstrates the power of a genetic screen that combines gene trap mutagenesis and FACS analysis in mouse ES cells to identify mitochondrial phenotypes and to develop animal models of mitochondrial dysfunction.
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Affiliation(s)
- Taraka R. Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Carmen Stromberger
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Ming Ge
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Karen W. Eldin
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - William J. Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Kalko SG, Paco S, Jou C, Rodríguez MA, Meznaric M, Rogac M, Jekovec-Vrhovsek M, Sciacco M, Moggio M, Fagiolari G, De Paepe B, De Meirleir L, Ferrer I, Roig-Quilis M, Munell F, Montoya J, López-Gallardo E, Ruiz-Pesini E, Artuch R, Montero R, Torner F, Nascimento A, Ortez C, Colomer J, Jimenez-Mallebrera C. Transcriptomic profiling of TK2 deficient human skeletal muscle suggests a role for the p53 signalling pathway and identifies growth and differentiation factor-15 as a potential novel biomarker for mitochondrial myopathies. BMC Genomics 2014; 15:91. [PMID: 24484525 PMCID: PMC3937154 DOI: 10.1186/1471-2164-15-91] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 01/28/2014] [Indexed: 02/08/2023] Open
Abstract
Background Mutations in the gene encoding thymidine kinase 2 (TK2) result in the myopathic form of mitochondrial DNA depletion syndrome which is a mitochondrial encephalomyopathy presenting in children. In order to unveil some of the mechanisms involved in this pathology and to identify potential biomarkers and therapeutic targets we have investigated the gene expression profile of human skeletal muscle deficient for TK2 using cDNA microarrays. Results We have analysed the whole transcriptome of skeletal muscle from patients with TK2 mutations and compared it to normal muscle and to muscle from patients with other mitochondrial myopathies. We have identified a set of over 700 genes which are differentially expressed in TK2 deficient muscle. Bioinformatics analysis reveals important changes in muscle metabolism, in particular, in glucose and glycogen utilisation, and activation of the starvation response which affects aminoacid and lipid metabolism. We have identified those transcriptional regulators which are likely to be responsible for the observed changes in gene expression. Conclusion Our data point towards the tumor suppressor p53 as the regulator at the centre of a network of genes which are responsible for a coordinated response to TK2 mutations which involves inflammation, activation of muscle cell death by apoptosis and induction of growth and differentiation factor 15 (GDF-15) in muscle and serum. We propose that GDF-15 may represent a potential novel biomarker for mitochondrial dysfunction although further studies are required.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Cecilia Jimenez-Mallebrera
- Neuromuscular Unit, Neurology Department, Fundación Sant Joan de Déu, Hospital Sant Joan de Déu, Barcelona, Spain.
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Pinto M, Moraes CT. Mitochondrial genome changes and neurodegenerative diseases. Biochim Biophys Acta Mol Basis Dis 2013; 1842:1198-207. [PMID: 24252612 DOI: 10.1016/j.bbadis.2013.11.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 11/06/2013] [Accepted: 11/08/2013] [Indexed: 12/12/2022]
Abstract
Mitochondria are essential organelles within the cell where most of the energy production occurs by the oxidative phosphorylation system (OXPHOS). Critical components of the OXPHOS are encoded by the mitochondrial DNA (mtDNA) and therefore, mutations involving this genome can be deleterious to the cell. Post-mitotic tissues, such as muscle and brain, are most sensitive to mtDNA changes, due to their high energy requirements and non-proliferative status. It has been proposed that mtDNA biological features and location make it vulnerable to mutations, which accumulate over time. However, although the role of mtDNA damage has been conclusively connected to neuronal impairment in mitochondrial diseases, its role in age-related neurodegenerative diseases remains speculative. Here we review the pathophysiology of mtDNA mutations leading to neurodegeneration and discuss the insights obtained by studying mouse models of mtDNA dysfunction.
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Affiliation(s)
- Milena Pinto
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Cell Biology, 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; Neuroscience Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Bird MJ, Thorburn DR, Frazier AE. Modelling biochemical features of mitochondrial neuropathology. Biochim Biophys Acta Gen Subj 2013; 1840:1380-92. [PMID: 24161927 DOI: 10.1016/j.bbagen.2013.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/29/2013] [Accepted: 10/11/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND The neuropathology of mitochondrial disease is well characterised. However, pathophysiological mechanisms at the level of biochemistry and cell biology are less clear. Progress in this area has been hampered by the limited accessibility of neurologically relevant material for analysis. SCOPE OF REVIEW Here we discuss the recent development of a variety of model systems that have greatly extended our capacity to understand the biochemical features associated with mitochondrial neuropathology. These include animal and cell based models, with mutations in both nuclear and mitochondrial DNA encoded genes, which aim to recapitulate the neuropathology and cellular biochemistry of mitochondrial diseases. MAJOR CONCLUSIONS Analysis of neurological tissue and cells from these models suggests that although there is no unifying mode of pathogenesis, dysfunction of the oxidative phosphorylation (OXPHOS) system is often central. This can be associated with altered reactive oxygen species (ROS) generation, disruption of the mitochondrial membrane potential (ΔΨm) and inadequate ATP synthesis. Thus, other cellular processes such as calcium (Ca(2+)) homeostasis, cellular signaling and mitochondrial morphology could be altered, ultimately compromising viability of neuronal cells. GENERAL SIGNIFICANCE Mechanisms of neuronal dysfunction in mitochondrial disease are only just beginning to be characterised, are system dependent and complex, and not merely driven by energy deficiency. The diversity of pathogenic mechanisms emphasises the need for characterisation in a wide range of models, as different therapeutic strategies are likely to be needed for different diseases. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Matthew J Bird
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia
| | - David R Thorburn
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia; Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - Ann E Frazier
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia.
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Cámara Y, González-Vioque E, Scarpelli M, Torres-Torronteras J, Martí R. Feeding the deoxyribonucleoside salvage pathway to rescue mitochondrial DNA. Drug Discov Today 2013; 18:950-7. [DOI: 10.1016/j.drudis.2013.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/27/2013] [Accepted: 06/19/2013] [Indexed: 12/16/2022]
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