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Abstract
Mitochondrial diseases require customized approaches for reproductive counseling, addressing differences in recurrence risks and reproductive options. The majority of mitochondrial diseases is caused by mutations in nuclear genes and segregate in a Mendelian way. Prenatal diagnosis (PND) or preimplantation genetic testing (PGT) are available to prevent the birth of another severely affected child. In at least 15%-25% of cases, mitochondrial diseases are caused by mitochondrial DNA (mtDNA) mutations, which can occur de novo (25%) or be maternally inherited. For de novo mtDNA mutations, the recurrence risk is low and PND can be offered for reassurance. For maternally inherited, heteroplasmic mtDNA mutations, the recurrence risk is often unpredictable, due to the mitochondrial bottleneck. PND for mtDNA mutations is technically possible, but often not applicable given limitations in predicting the phenotype. Another option for preventing the transmission of mtDNA diseases is PGT. Embryos with mutant load below the expression threshold are being transferred. Oocyte donation is another safe option to prevent the transmission of mtDNA disease to a future child for couples who reject PGT. Recently, mitochondrial replacement therapy (MRT) became available for clinical application as an alternative to prevent the transmission of heteroplasmic and homoplasmic mtDNA mutations.
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2
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Abstract
Leigh syndrome, or subacute necrotizing encephalomyelopathy, was initially recognized as a neuropathological entity in 1951. Bilateral symmetrical lesions, typically extending from the basal ganglia and thalamus through brainstem structures to the posterior columns of the spinal cord, are characterized microscopically by capillary proliferation, gliosis, severe neuronal loss, and relative preservation of astrocytes. Leigh syndrome is a pan-ethnic disorder usually with onset in infancy or early childhood, but late-onset forms occur, including in adult life. Over the last six decades it has emerged that this complex neurodegenerative disorder encompasses more than 100 separate monogenic disorders associated with enormous clinical and biochemical heterogeneity. This chapter discusses clinical, biochemical and neuropathological aspects of the disorder, and postulated pathomechanisms. Known genetic causes, including defects of 16 mitochondrial DNA (mtDNA) genes and approaching 100 nuclear genes, are categorized into disorders of subunits and assembly factors of the five oxidative phosphorylation enzymes, disorders of pyruvate metabolism and vitamin and cofactor transport and metabolism, disorders of mtDNA maintenance, and defects of mitochondrial gene expression, protein quality control, lipid remodeling, dynamics, and toxicity. An approach to diagnosis is presented, together with known treatable causes and an overview of current supportive management options and emerging therapies on the horizon.
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Affiliation(s)
- Shamima Rahman
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, United Kingdom; Metabolic Medicine Department, Great Ormond Street Hospital for Children, London, United Kingdom.
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3
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Genetic testing for mitochondrial disease: the United Kingdom best practice guidelines. Eur J Hum Genet 2023; 31:148-163. [PMID: 36513735 PMCID: PMC9905091 DOI: 10.1038/s41431-022-01249-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/12/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
Primary mitochondrial disease describes a diverse group of neuro-metabolic disorders characterised by impaired oxidative phosphorylation. Diagnosis is challenging; >350 genes, both nuclear and mitochondrial DNA (mtDNA) encoded, are known to cause mitochondrial disease, leading to all possible inheritance patterns and further complicated by heteroplasmy of the multicopy mitochondrial genome. Technological advances, particularly next-generation sequencing, have driven a shift in diagnostic practice from 'biopsy first' to genome-wide analyses of blood and/or urine DNA. This has led to the need for a reference framework for laboratories involved in mitochondrial genetic testing to facilitate a consistent high-quality service. In the United Kingdom, consensus guidelines have been prepared by a working group of Clinical Scientists from the NHS Highly Specialised Service followed by national laboratory consultation. These guidelines summarise current recommended technologies and methodologies for the analysis of mtDNA and nuclear-encoded genes in patients with suspected mitochondrial disease. Genetic testing strategies for diagnosis, family testing and reproductive options including prenatal diagnosis are outlined. Importantly, recommendations for the minimum levels of mtDNA testing for the most common referral reasons are included, as well as guidance on appropriate referrals and information on the minimal appropriate gene content of panels when analysing nuclear mitochondrial genes. Finally, variant interpretation and recommendations for reporting of results are discussed, focussing particularly on the challenges of interpreting and reporting mtDNA variants.
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Russo V, Ancora M, Gatta V, Orsini M, Prencipe G, Peserico A, Colosimo A, El Khatib M, Mauro A, Di Berardino C, Scialabba S, Tiboni GM, Marcacci M, Cammà C, Barboni B. Profiling of mitochondrial heteroplasmy in single human oocytes by next-generation sequencing. Mol Reprod Dev 2022; 89:646-654. [PMID: 36444830 DOI: 10.1002/mrd.23655] [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: 05/23/2022] [Revised: 10/14/2022] [Accepted: 11/16/2022] [Indexed: 11/30/2022]
Abstract
Mitochondrial DNA (mtDNA) plays a crucial role in the development of a competent oocyte. Indeed, mtDNA alterations may predispose to chromosome nondisjunction, resulting in infertility due to a reduced vitality and quality of oocytes and embryos. In this methods paper, the multiple displacement amplification approach was applied in combination with next-generation sequencing (NGS) to amplify and sequence, in single-end, the entire mtDNA of single human oocytes to directly construct genomic NGS libraries, and subsequently, to highlight and quantify the mutations they presented. The bioinformatic workflow was carried out with a specific ad hoc developed in-house software. This approach proved to be sensitive and specific, also highlighting the mutations present in heteroplasmy, showing deletion, insertion or substitution mutations in the genes involved in the respiratory chain, even if the found variants were benign or of uncertain meaning. The analysis of mtDNA mutations in the oocyte could provide a better understanding of specific genetic abnormalities and of their possible effect on oocyte developmental competence. This study shows how this approach, based on a massive parallel sequencing of clonally amplified DNA molecules, allows to sequence the entire mitochondrial genome of single oocytes in a short time and with a single analytical run and to verify mtDNA mutations.
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Affiliation(s)
- Valentina Russo
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Massimo Ancora
- Laboratory of Molecular Biology and Genomics, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Valentina Gatta
- Center for Advanced Studies and Technology (CAST), University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy.,Department of Psychological, Health and Territory Sciences, School of Medicine and Health Sciences, University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - Massimiliano Orsini
- Laboratory of Molecular Biology and Genomics, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy.,Laboratory of Microbial Ecology and Genomics, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy
| | - Giuseppe Prencipe
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Alessia Peserico
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Alessia Colosimo
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Mohammad El Khatib
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Annunziata Mauro
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Chiara Di Berardino
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
| | - Silvia Scialabba
- Laboratory of Molecular Biology and Genomics, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Gian Mario Tiboni
- Department of Medical, Oral and Biotechnological Sciences (DSMOB), University "G. d'Annunzio" of Chieti-Pescara, Chieti, Italy
| | - Maurilia Marcacci
- Laboratory of Molecular Biology and Genomics, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Cesare Cammà
- Laboratory of Molecular Biology and Genomics, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Barbara Barboni
- Unit of Basic and Applied Biosciences, Department of Bioscience and Agro-Food and Environmental Technology, University of Teramo, Teramo, Italy
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Lee J, Willett CS. Frequent Paternal Mitochondrial Inheritance and Rapid Haplotype Frequency Shifts in Copepod Hybrids. J Hered 2022; 113:171-183. [PMID: 35575078 DOI: 10.1093/jhered/esab068] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are assumed to be maternally inherited in most animal species, and this foundational concept has fostered advances in phylogenetics, conservation, and population genetics. Like other animals, mitochondria were thought to be solely maternally inherited in the marine copepod Tigriopus californicus, which has served as a useful model for studying mitonuclear interactions, hybrid breakdown, and environmental tolerance. However, we present PCR, Sanger sequencing, and Illumina Nextera sequencing evidence that extensive paternal mitochondrial DNA (mtDNA) transmission is occurring in inter-population hybrids of T. californicus. PCR on four types of crosses between three populations (total sample size of 376 F1 individuals) with 20% genome-wide mitochondrial divergence showed 2% to 59% of F1 hybrids with both paternal and maternal mtDNA, where low and high paternal leakage values were found in different cross directions of the same population pairs. Sequencing methods further verified nucleotide similarities between F1 mtDNA and paternal mtDNA sequences. Interestingly, the paternal mtDNA in F1s from some crosses inherited haplotypes that were uncommon in the paternal population. Compared to some previous research on paternal leakage, we employed more rigorous methods to rule out contamination and false detection of paternal mtDNA due to non-functional nuclear mitochondrial DNA fragments. Our results raise the potential that other animal systems thought to only inherit maternal mitochondria may also have paternal leakage, which would then affect the interpretation of past and future population genetics or phylogenetic studies that rely on mitochondria as uniparental markers.
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Affiliation(s)
- Jeeyun Lee
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Christopher S Willett
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Musson R, Gąsior Ł, Bisogno S, Ptak GE. DNA damage in preimplantation embryos and gametes: specification, clinical relevance and repair strategies. Hum Reprod Update 2022; 28:376-399. [PMID: 35021196 PMCID: PMC9071077 DOI: 10.1093/humupd/dmab046] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/13/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND DNA damage is a hazard that affects all cells of the body. DNA-damage repair (DDR) mechanisms are in place to repair damage and restore cellular function, as are other damage-induced processes such as apoptosis, autophagy and senescence. The resilience of germ cells and embryos in response to DNA damage is less well studied compared with other cell types. Given that recent studies have described links between embryonic handling techniques and an increased likelihood of disease in post-natal life, an update is needed to summarize the sources of DNA damage in embryos and their capacity to repair it. In addition, numerous recent publications have detailed novel techniques for detecting and repairing DNA damage in embryos. This information is of interest to medical or scientific personnel who wish to obtain undamaged embryos for use in offspring generation by ART. OBJECTIVE AND RATIONALE This review aims to thoroughly discuss sources of DNA damage in male and female gametes and preimplantation embryos. Special consideration is given to current knowledge and limits in DNA damage detection and screening strategies. Finally, obstacles and future perspectives in clinical diagnosis and treatment (repair) of DNA damaged embryos are discussed. SEARCH METHODS Using PubMed and Google Scholar until May 2021, a comprehensive search for peer-reviewed original English-language articles was carried out using keywords relevant to the topic with no limits placed on time. Keywords included ‘DNA damage repair’, ‘gametes’, ‘sperm’, ‘oocyte’, ‘zygote’, ‘blastocyst’ and ‘embryo’. References from retrieved articles were also used to obtain additional articles. Literature on the sources and consequences of DNA damage on germ cells and embryos was also searched. Additional papers cited by primary references were included. Results from our own studies were included where relevant. OUTCOMES DNA damage in gametes and embryos can differ greatly based on the source and severity. This damage affects the development of the embryo and can lead to long-term health effects on offspring. DDR mechanisms can repair damage to a certain extent, but the factors that play a role in this process are numerous and altogether not well characterized. In this review, we describe the multifactorial origin of DNA damage in male and female gametes and in the embryo, and suggest screening strategies for the selection of healthy gametes and embryos. Furthermore, possible therapeutic solutions to decrease the frequency of DNA damaged gametes and embryos and eventually to repair DNA and increase mitochondrial quality in embryos before their implantation is discussed. WIDER IMPLICATIONS Understanding DNA damage in gametes and embryos is essential for the improvement of techniques that could enhance embryo implantation and pregnancy success. While our knowledge about DNA damage factors and regulatory mechanisms in cells has advanced greatly, the number of feasible practical techniques to avoid or repair damaged embryos remains scarce. Our intention is therefore to focus on strategies to obtain embryos with as little DNA damage as possible, which will impact reproductive biology research with particular significance for reproductive clinicians and embryologists.
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Affiliation(s)
- Richard Musson
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Łukasz Gąsior
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Simona Bisogno
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Grażyna Ewa Ptak
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
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Dawod PGA, Jancic J, Marjanovic A, Brankovic M, Jankovic M, Samardzic J, Gamil Anwar Dawod A, Novakovic I, Abdel Motaleb FI, Radlovic V, Kostic VS, Nikolic D. Mutational Analysis and mtDNA Haplogroup Characterization in Three Serbian Cases of Mitochondrial Encephalomyopathies and Literature Review. Diagnostics (Basel) 2021; 11:1969. [PMID: 34829316 PMCID: PMC8620769 DOI: 10.3390/diagnostics11111969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial encephalomyopathies (MEMP) are heterogeneous multisystem disorders frequently associated with mitochondrial DNA (mtDNA) mutations. Clinical presentation varies considerably in age of onset, course, and severity up to death in early childhood. In this study, we performed molecular genetic analysis for mtDNA pathogenic mutation detection in Serbian children, preliminary diagnosed clinically, biochemically and by brain imaging for mitochondrial encephalomyopathies disorders. Sanger sequencing analysis in three Serbian probands revealed two known pathogenic mutations. Two probands had a heteroplasmic point mutation m.3243A>G in the MT-TL1 gene, which confirmed mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode syndrome (MELAS), while a single case clinically manifested for Leigh syndrome had an almost homoplasmic (close to 100%) m.8993T>G mutation in the MT-ATP6 gene. After full mtDNA MITOMASTER analysis and PhyloTree build 17, we report MELAS' association with haplogroups U and H (U2e and H15 subclades); likewise, the mtDNA-associated Leigh syndrome proband shows a preference for haplogroup H (H34 subclade). Based on clinical-genetic correlation, we suggest that haplogroup H may contribute to the mitochondrial encephalomyopathies' phenotypic variability of the patients in our study. We conclude that genetic studies for the distinctive mitochondrial encephalomyopathies should be well-considered for realizing clinical severity and possible outcomes.
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Affiliation(s)
- Phepy G. A. Dawod
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt;
| | - Jasna Jancic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Clinic of Neurology and Psychiatry of Children and Youth, 11000 Belgrade, Serbia
| | - Ana Marjanovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
| | - Marija Brankovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
| | - Milena Jankovic
- Neurology Clinic, Clinical Center of Serbia, 11000 Belgrade, Serbia;
| | - Janko Samardzic
- Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;
| | - Ayman Gamil Anwar Dawod
- Internal Medicine, Hepatogastroenterology and Endoscopy Department, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt;
| | - Ivana Novakovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
| | - Fayda I. Abdel Motaleb
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt;
| | - Vladimir Radlovic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Pediatric Surgery Department, University Children’s Hospital, 11000 Belgrade, Serbia
| | - Vladimir S. Kostic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Neurology Clinic, Clinical Center of Serbia, 11000 Belgrade, Serbia;
| | - Dejan Nikolic
- Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia; (P.G.A.D.); (J.J.); (A.M.); (M.B.); (I.N.); (V.R.); (V.S.K.)
- Physical Medicine and Rehabilitation Department, University Children’s Hospital, Tirsova 10, 11000 Belgrade, Serbia
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Spath K, Babariya D, Konstantinidis M, Lowndes J, Child T, Grifo JA, Poulton J, Wells D. Clinical application of sequencing-based methods for parallel preimplantation genetic testing for mitochondrial DNA disease and aneuploidy. Fertil Steril 2021; 115:1521-1532. [PMID: 33745725 DOI: 10.1016/j.fertnstert.2021.01.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To validate and apply a strategy permitting parallel preimplantation genetic testing (PGT) for mitochondrial DNA (mtDNA) disease and aneuploidy (PGT-A). DESIGN Preclinical test validation and case reports. SETTING Fertility centers. Diagnostics laboratory. PATIENTS Four patients at risk of transmitting mtDNA disease caused by m.8993T>G (Patients A and B), m.10191T>G (Patient C), and m.3243A>G (Patient D). Patients A, B, and C had affected children. Patients A and D displayed somatic heteroplasmy for mtDNA mutations. INTERVENTIONS Embryo biopsy, genetic testing, and uterine transfer of embryos predicted to be euploid and mutation-free. MAIN OUTCOME MEASURES Test accuracy, treatment outcomes, and mutation segregation. RESULTS Accuracy of mtDNA mutation quantification was confirmed. The test was compatible with PGT-A, and half of the embryos tested were shown to be aneuploid (16/33). Mutations were detected in approximately 40% of embryo biopsies from Patients A and D (10/24) but in none from Patients B and C (n = 29). Patients B and C had healthy children following PGT and natural conception, respectively. The m.8993T>G mutation displayed skewed segregation, whereas m.3243A>G mutation levels were relatively low and potentially impacted embryo development. CONCLUSIONS Considering the high aneuploidy rate, strategies providing a combination of PGT for mtDNA disease and aneuploidy may be advantageous compared with approaches that consider only mtDNA. Heteroplasmic women had a higher incidence of affected embryos than those with undetectable somatic mutant mtDNA but were still able to produce mutation-free embryos. While not conclusive, the results are consistent with the existence of mutation-specific segregation mechanisms occurring during oogenesis and possibly embryogenesis.
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Affiliation(s)
- Katharina Spath
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom; Juno Genetics, Oxford, United Kingdom.
| | - Dhruti Babariya
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom; Juno Genetics, Oxford, United Kingdom
| | | | - Jo Lowndes
- Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Nuffield Orthopaedic Centre, Oxford, United Kingdom
| | - Tim Child
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom; Oxford Fertility, Fertility Partnership, Oxford, United Kingdom
| | | | - Joanna Poulton
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom
| | - Dagan Wells
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, United Kingdom; Juno Genetics, Oxford, United Kingdom
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Steffann J, Monnot S, Magen M, Assouline Z, Gigarel N, Ville Y, Salomon L, Bessiere B, Martinovic J, Rötig A, Bengoa J, Borghèse R, Munnich A, Barcia G, Bonnefont JP. A retrospective study on the efficacy of prenatal diagnosis for pregnancies at risk of mitochondrial DNA disorders. Genet Med 2020; 23:720-731. [PMID: 33303968 DOI: 10.1038/s41436-020-01043-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 11/11/2020] [Accepted: 11/11/2020] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Prenatal diagnosis of mitochondrial DNA (mtDNA) disorders is challenging due to potential instability of fetal mutant loads and paucity of data connecting prenatal mutant loads to postnatal observations. Retrospective study of our prenatal cohort aims to examine the efficacy of prenatal diagnosis to improve counseling and reproductive options for those with pregnancies at risk of mtDNA disorders. METHODS We report on a retrospective review of 20 years of prenatal diagnosis of pathogenic mtDNA variants in 80 pregnant women and 120 fetuses. RESULTS Patients with undetectable pathogenic variants (n = 29) consistently had fetuses free of variants, while heteroplasmic women (n = 51) were very likely to transmit their variant (57/78 fetuses, 73%). In the latter case, 26 pregnancies were terminated because fetal mutant loads were >40%. Of the 84 children born, 27 were heteroplasmic (mutant load <65%). To date, no medical problems related to mitochondrial dysfunction have been reported. CONCLUSION Placental heterogeneity of mutant loads questioned the reliability of chorionic villous testing. Fetal mutant load stability, however, suggests the reliability of a single analysis of amniotic fluid at any stage of pregnancy for prenatal diagnosis of mtDNA disorders. Mutant loads under 40% reliably predict lack of symptoms in the progeny of heteroplasmic women.
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Affiliation(s)
- Julie Steffann
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France. .,Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France.
| | - Sophie Monnot
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Maryse Magen
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Zahra Assouline
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Nadine Gigarel
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Yves Ville
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service d'Obstétrique - Maternité, chirurgie médecine et imagerie fœtale, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Laurent Salomon
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service d'Obstétrique - Maternité, chirurgie médecine et imagerie fœtale, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Bettina Bessiere
- Service d'histo-embryologie et fœtopathologie, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Jelena Martinovic
- Unité de Foetopathologie, Hôpital Antoine Béclère, GHU Paris Saclay, AP-HP, Clamart, France
| | - Agnès Rötig
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France
| | - Joana Bengoa
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Roxana Borghèse
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Arnold Munnich
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Giulia Barcia
- Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
| | - Jean-Paul Bonnefont
- Université de Paris-Sorbonne Paris Cité, Imagine Institute, INSERM UMR1163, Paris, France.,Service de Génétique Moléculaire, Groupe hospitalier Necker-Enfants Malades, AP-HP, Paris, France
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10
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Walker MA, Lareau CA, Ludwig LS, Karaa A, Sankaran VG, Regev A, Mootha VK. Purifying Selection against Pathogenic Mitochondrial DNA in Human T Cells. N Engl J Med 2020; 383:1556-1563. [PMID: 32786181 PMCID: PMC7593775 DOI: 10.1056/nejmoa2001265] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Many mitochondrial diseases are caused by mutations in mitochondrial DNA (mtDNA). Patients' cells contain a mixture of mutant and nonmutant mtDNA (a phenomenon called heteroplasmy). The proportion of mutant mtDNA varies across patients and among tissues within a patient. We simultaneously assayed single-cell heteroplasmy and cell state in thousands of blood cells obtained from three unrelated patients who had A3243G-associated mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes. We observed a broad range of heteroplasmy across all cell types but also found markedly reduced heteroplasmy in T cells, a finding consistent with purifying selection within this lineage. We observed this pattern in six additional patients who had heteroplasmic A3243G without strokelike episodes. (Funded by the Marriott Foundation and others.).
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Affiliation(s)
- Melissa A Walker
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
| | - Caleb A Lareau
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
| | - Leif S Ludwig
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
| | - Amel Karaa
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
| | - Vijay G Sankaran
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
| | - Aviv Regev
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
| | - Vamsi K Mootha
- From the Departments of Molecular Biology (M.A.W., V.K.M.), Neurology (M.A.W.), and Medicine (V.K.M) and the Genetics Unit, Department of Pediatrics (A.K.), Massachusetts General Hospital, Howard Hughes Medical Institute (M.A.W., A.R., V.K.M.), the Division of Hematology-Oncology, Boston Children's Hospital (C.A.L., L.S.L., V.G.S.), the Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School (C.A.L., L.S.L., V.G.S.), the Department of Systems Biology, Harvard Medical School (V.K.M.), and Harvard Medical School (M.A.W., A.K.), Boston, and the Klarman Cell Observatory (L.S.L., A.R.), Broad Institute of MIT (Massachusetts Institute of Technology) and Harvard (M.A.W., C.A.L., V.G.S., V.K.M.), the Harvard Stem Cell Institute (V.G.S.), and the Department of Biology and Koch Institute of Integrative Cancer Research, Massachusetts Institute of Technology (A.R.), Cambridge - both in Massachusetts
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11
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Nissanka N, Moraes CT. Mitochondrial DNA heteroplasmy in disease and targeted nuclease-based therapeutic approaches. EMBO Rep 2020; 21:e49612. [PMID: 32073748 DOI: 10.15252/embr.201949612] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/11/2019] [Accepted: 01/29/2020] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial DNA (mtDNA) encodes a subset of the genes which are responsible for oxidative phosphorylation. Pathogenic mutations in the human mtDNA are often heteroplasmic, where wild-type mtDNA species co-exist with the pathogenic mtDNA and a bioenergetic defect is only seen when the pathogenic mtDNA percentage surpasses a threshold for biochemical manifestations. mtDNA segregation during germline development can explain some of the extreme variation in heteroplasmy from one generation to the next. Patients with high heteroplasmy for deleterious mtDNA species will likely suffer from bona-fide mitochondrial diseases, which currently have no cure. Shifting mtDNA heteroplasmy toward the wild-type mtDNA species could provide a therapeutic option to patients. Mitochondrially targeted engineered nucleases, such as mitoTALENs and mitoZFNs, have been used in vitro in human cells harboring pathogenic patient-derived mtDNA mutations and more recently in vivo in a mouse model of a pathogenic mtDNA point mutation. These gene therapy tools for shifting mtDNA heteroplasmy can also be used in conjunction with other therapies aimed at eliminating and/or preventing the transfer of pathogenic mtDNA from mother to child.
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Affiliation(s)
- Nadee Nissanka
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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12
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Johnston IG. Varied Mechanisms and Models for the Varying Mitochondrial Bottleneck. Front Cell Dev Biol 2019; 7:294. [PMID: 31824946 PMCID: PMC6879659 DOI: 10.3389/fcell.2019.00294] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/06/2019] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial DNA (mtDNA) molecules exist in populations within cells, and may carry mutations. Different cells within an organism, and organisms within a family, may have different proportions of mutant mtDNA in these cellular populations. This diversity is often thought of as arising from a “genetic bottleneck.” This article surveys approaches to characterize and model the generation of this genetic diversity, aiming to provide an introduction to the range of concepts involved, and to highlight some recent advances in understanding. In particular, differences between the statistical “genetic bottleneck” (mutant proportion spread) and the physical mtDNA bottleneck and other cellular processes are highlighted. Particular attention is paid to the quantitative analysis of the “genetic bottleneck,” estimation of its magnitude from observed data, and inference of its underlying mechanisms. Evidence that the “genetic bottleneck” (mutant proportion spread) varies with age, between individuals and species, and across mtDNA sequences, is described. The interpretation issues that arise from sampling errors, selection, and different quantitative definitions are also discussed.
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Affiliation(s)
- Iain G Johnston
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Bergen, Bergen, Norway
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13
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Poulton J, Steffann J, Burgstaller J, McFarland R. 243rd ENMC international workshop: Developing guidelines for management of reproductive options for families with maternally inherited mtDNA disease, Amsterdam, the Netherlands, 22–24 March 2019. Neuromuscul Disord 2019; 29:725-733. [DOI: 10.1016/j.nmd.2019.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/13/2019] [Indexed: 01/13/2023]
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14
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Otten ABC, Sallevelt SCEH, Carling PJ, Dreesen JCFM, Drüsedau M, Spierts S, Paulussen ADC, de Die-Smulders CEM, Herbert M, Chinnery PF, Samuels DC, Lindsey P, Smeets HJM. Mutation-specific effects in germline transmission of pathogenic mtDNA variants. Hum Reprod 2019; 33:1331-1341. [PMID: 29850888 DOI: 10.1093/humrep/dey114] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 05/15/2018] [Indexed: 12/31/2022] Open
Abstract
STUDY QUESTION Does germline selection (besides random genetic drift) play a role during the transmission of heteroplasmic pathogenic mitochondrial DNA (mtDNA) mutations in humans? SUMMARY ANSWER We conclude that inheritance of mtDNA is mutation-specific and governed by a combination of random genetic drift and negative and/or positive selection. WHAT IS KNOWN ALREADY mtDNA inherits maternally through a genetic bottleneck, but the underlying mechanisms are largely unknown. Although random genetic drift is recognized as an important mechanism, selection mechanisms are thought to play a role as well. STUDY DESIGN, SIZE, DURATION We determined the mtDNA mutation loads in 160 available oocytes, zygotes, and blastomeres of five carriers of the m.3243A>G mutation, one carrier of the m.8993T>G mutation, and one carrier of the m.14487T>C mutation. PARTICIPANTS/MATERIALS, SETTING, METHODS Mutation loads were determined in PGD samples using PCR assays and analysed mathematically to test for random sampling effects. In addition, a meta-analysis has been performed on mutation load transmission data in the literature to confirm the results of the PGD samples. MAIN RESULTS AND THE ROLE OF CHANCE By applying the Kimura distribution, which assumes random mechanisms, we found that mtDNA segregations patterns could be explained by variable bottleneck sizes among all our carriers (moment estimates ranging from 10 to 145). Marked differences in the bottleneck size would determine the probability that a carrier produces offspring with mutations markedly different than her own. We investigated whether bottleneck sizes might also be influenced by non-random mechanisms. We noted a consistent absence of high mutation loads in all our m.3243A>G carriers, indicating non-random events. To test this, we fitted a standard and a truncated Kimura distribution to the m.3243A>G segregation data. A Kimura distribution truncated at 76.5% heteroplasmy has a significantly better fit (P-value = 0.005) than the standard Kimura distribution. For the m.8993T>G mutation, we suspect a skewed mutation load distribution in the offspring. To test this hypothesis, we performed a meta-analysis on published blood mutation levels of offspring-mother (O-M) transmission for the m.3243A>G and m.8993T>G mutations. This analysis revealed some evidence that the O-M ratios for the m.8993T>G mutation are different from zero (P-value <0.001), while for the m.3243A>G mutation there was little evidence that the O-M ratios are non-zero. Lastly, for the m.14487T>G mutation, where the whole range of mutation loads was represented, we found no indications for selective events during its transmission. LARGE SCALE DATA All data are included in the Results section of this article. LIMITATIONS, REASON FOR CAUTION The availability of human material for the mutations is scarce, requiring additional samples to confirm our findings. WIDER IMPLICATIONS OF THE FINDINGS Our data show that non-random mechanisms are involved during mtDNA segregation. We aimed to provide the mechanisms underlying these selection events. One explanation for selection against high m.3243A>G mutation loads could be, as previously reported, a pronounced oxidative phosphorylation (OXPHOS) deficiency at high mutation loads, which prohibits oogenesis (e.g. progression through meiosis). No maximum mutation loads of the m.8993T>G mutation seem to exist, as the OXPHOS deficiency is less severe, even at levels close to 100%. In contrast, high mutation loads seem to be favoured, probably because they lead to an increased mitochondrial membrane potential (MMP), a hallmark on which healthy mitochondria are being selected. This hypothesis could provide a possible explanation for the skewed segregation pattern observed. Our findings are corroborated by the segregation pattern of the m.14487T>C mutation, which does not affect OXPHOS and MMP significantly, and its transmission is therefore predominantly determined by random genetic drift. Our conclusion is that mutation-specific selection mechanisms occur during mtDNA inheritance, which has implications for PGD and mitochondrial replacement therapy. STUDY FUNDING/COMPETING INTEREST(S) This work has been funded by GROW-School of Oncology and Developmental Biology. The authors declare no competing interests.
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Affiliation(s)
- Auke B C Otten
- Department of Genetics and Cell Biology, School for Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, the Netherlands
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands
| | - Phillippa J Carling
- Department of Neuroscience, Sheffield institute for translational neuroscience (SITraN), University of Sheffield, Sheffield, UK
| | - Joseph C F M Dreesen
- Department of Clinical Genetics, Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands
| | - Marion Drüsedau
- Department of Clinical Genetics, Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands
| | - Sabine Spierts
- Department of Clinical Genetics, Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands
| | - Aimee D C Paulussen
- Department of Clinical Genetics, Maastricht University Medical Centre+ (MUMC+), Maastricht, the Netherlands
| | | | - Mary Herbert
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Patrick F Chinnery
- Department of Clinical Neuroscience, School of Clinical Medicine, University of Cambridge, Cambridge, UK.,Medical Research Council Mitochondrial Biology Unit, Cambridge, Biomedical Campus, Cambridge, UK
| | - David C Samuels
- Department of Molecular Physiology and Biophysics, Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Patrick Lindsey
- Department of Genetics and Cell Biology, School for Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, the Netherlands
| | - Hubert J M Smeets
- Department of Genetics and Cell Biology, School for Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, the Netherlands
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15
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Clinical syndromes associated with mtDNA mutations: where we stand after 30 years. Essays Biochem 2018; 62:235-254. [DOI: 10.1042/ebc20170097] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/16/2023]
Abstract
The landmark year 1988 can be considered as the birthdate of mitochondrial medicine, when the first pathogenic mutations affecting mtDNA were associated with human diseases. Three decades later, the field still expands and we are not ‘scraping the bottom of the barrel’ yet. Despite the tremendous progress in terms of molecular characterization and genotype/phenotype correlations, for the vast majority of cases we still lack a deep understanding of the pathogenesis, good models to study, and effective therapeutic options. However, recent technological advances including somatic cell reprogramming to induced pluripotent stem cells (iPSCs), organoid technology, and tailored endonucleases provide unprecedented opportunities to fill these gaps, casting hope to soon cure the major primary mitochondrial phenotypes reviewed here. This group of rare diseases represents a key model for tackling the pathogenic mechanisms involving mitochondrial biology relevant to much more common disorders that affect our currently ageing population, such as diabetes and metabolic syndrome, neurodegenerative and inflammatory disorders, and cancer.
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16
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Plucnara M, Eksin E, Erdem A, Fojta M. Electrochemical Detection of SNP in Human Mitochondrial DNA Using Cyclic Primer Extension with Biotinylated Nucletides and Enzymatic Labeling at Disposable Pencil Graphite Electrodes. ELECTROANAL 2018. [DOI: 10.1002/elan.201800314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Medard Plucnara
- Institute of Biophysics Academy of Sciences of the Czech Republic, v.v.i. Královopolská 135 612 65 Brno Czech Republic
| | - Ece Eksin
- Ege University, Faculty of Pharmacy Analytical Chemistry Department 35100 Bornova, Izmir Turkey
- Ege University, Graduate School of Natural and Applied Science Biotechnology Department 35100 Bornova, Izmir Turkey
| | - Arzum Erdem
- Ege University, Faculty of Pharmacy Analytical Chemistry Department 35100 Bornova, Izmir Turkey
- Ege University, Graduate School of Natural and Applied Science Biotechnology Department 35100 Bornova, Izmir Turkey
| | - Miroslav Fojta
- Institute of Biophysics Academy of Sciences of the Czech Republic, v.v.i. Královopolská 135 612 65 Brno Czech Republic
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17
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Poulton J, Finsterer J, Yu-Wai-Man P. Genetic Counselling for Maternally Inherited Mitochondrial Disorders. Mol Diagn Ther 2018; 21:419-429. [PMID: 28536827 DOI: 10.1007/s40291-017-0279-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aim of this review was to provide an evidence-based approach to frequently asked questions relating to the risk of transmitting a maternally inherited mitochondrial disorder (MID). We do not address disorders linked with disturbed mitochondrial DNA (mtDNA) maintenance, causing mtDNA depletion or multiple mtDNA deletions, as these are autosomally inherited. The review addresses questions regarding prognosis, recurrence risks and the strategies available to prevent disease transmission. The clinical and genetic complexity of maternally inherited MIDs represent a major challenge for patients, their relatives and health professionals. Since many of the genetic and pathophysiological aspects of MIDs remain unknown, counselling of affected patients and at-risk family members remains difficult. MtDNA mutations are maternally transmitted or, more rarely, they are sporadic, occurring de novo (~25%). Females carrying homoplasmic mtDNA mutations will transmit the mutant species to all of their offspring, who may or may not exhibit a similar phenotype depending on modifying, secondary factors. Females carrying heteroplasmic mtDNA mutations will transmit a variable amount of mutant mtDNA to their offspring, which can result in considerable phenotypic heterogeneity among siblings. The majority of mtDNA rearrangements, such as single large-scale deletions, are sporadic, but there is a small risk of recurrence (~4%) among the offspring of affected women. The range and suitability of reproductive choices for prospective mothers is a complex area of mitochondrial medicine that needs to be managed by experienced healthcare professionals as part of a multidisciplinary team. Genetic counselling is facilitated by the identification of the underlying causative genetic defect. To provide more precise genetic counselling, further research is needed to clarify the secondary factors that account for the variable penetrance and the often marked differential expressivity of pathogenic mtDNA mutations both within and between families.
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Affiliation(s)
- Joanna Poulton
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford, UK
| | - Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180, Vienna, Austria.
| | - Patrick Yu-Wai-Man
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.,NIHR Biomedical Research Centre, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK.,Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
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18
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Craven L, Tang MX, Gorman GS, De Sutter P, Heindryckx B. Novel reproductive technologies to prevent mitochondrial disease. Hum Reprod Update 2018. [PMID: 28651360 DOI: 10.1093/humupd/dmx018] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The use of nuclear transfer (NT) has been proposed as a novel reproductive treatment to overcome the transmission of maternally-inherited mitochondrial DNA (mtDNA) mutations. Pathogenic mutations in mtDNA can cause a wide-spectrum of life-limiting disorders, collectively known as mtDNA disease, for which there are currently few effective treatments and no known cures. The many unique features of mtDNA make genetic counselling challenging for women harbouring pathogenic mtDNA mutations but reproductive options that involve medical intervention are available that will minimize the risk of mtDNA disease in their offspring. This includes PGD, which is currently offered as a clinical treatment but will not be suitable for all. The potential for NT to reduce transmission of mtDNA mutations has been demonstrated in both animal and human models, and has recently been clinically applied not only to prevent mtDNA disease but also for some infertility cases. In this review, we will interrogate the different NT techniques, including a discussion on the available safety and efficacy data of these technologies for mtDNA disease prevention. In addition, we appraise the evidence for the translational use of NT technologies in infertility. OBJECTIVE AND RATIONALE We propose to review the current scientific evidence regarding the clinical use of NT to prevent mitochondrial disease. SEARCH METHODS The scientific literature was investigated by searching PubMed database until Jan 2017. Relevant documents from Human Fertilisation and Embryology Authority as well as reports from both the scientific and popular media were also implemented. The above searches were based on the following key words: 'mitochondria', 'mitochondrial DNA'; 'mitochondrial DNA disease', 'fertility'; 'preimplantation genetic diagnosis', 'nuclear transfer', 'mitochondrial replacement' and 'mitochondrial donation'. OUTCOMES While NT techniques have been shown to effectively reduce the transmission of heteroplasmic mtDNA variants in animal models, and increasing evidence supports their use to prevent the transmission of human mtDNA disease, the need for robust, long-term evaluation is still warranted. Moreover, prenatal screening would still be strongly advocated in combination with the use of these IVF-based technologies. Scientific evidence to support the use of NT and other novel reproductive techniques for infertility is currently lacking. WIDER IMPLICATIONS It is mandatory that any new ART treatments are first adequately assessed in both animal and human models before the cautious implementation of these new therapeutic approaches is clinically undertaken. There is growing evidence to suggest that the translation of these innovative technologies into clinical practice should be cautiously adopted only in highly selected patients. Indeed, given the limited safety and efficacy data, close monitoring of any offspring remains paramount.
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Affiliation(s)
- Lyndsey Craven
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Mao-Xing Tang
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Gráinne S Gorman
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Petra De Sutter
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
| | - Björn Heindryckx
- Ghent-Fertility and Stem Cell Team (G-FaST), Department for Reproductive Medicine, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium
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19
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Burr SP, Pezet M, Chinnery PF. Mitochondrial DNA Heteroplasmy and Purifying Selection in the Mammalian Female Germ Line. Dev Growth Differ 2018; 60:21-32. [PMID: 29363102 DOI: 10.1111/dgd.12420] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 12/08/2017] [Indexed: 01/19/2023]
Abstract
Inherited mutations in the mitochondrial (mt)DNA are a major cause of human disease, with approximately 1 in 5000 people affected by one of the hundreds of identified pathogenic mtDNA point mutations or deletions. Due to the severe, and often untreatable, symptoms of many mitochondrial diseases, identifying how these mutations are inherited from one generation to the next has been an area of intense research in recent years. Despite large advances in our understanding of this complex process, many questions remain unanswered, with one of the most hotly debated being whether or not purifying selection acts against pathogenic mutations during germline development.
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Affiliation(s)
- Stephen P Burr
- MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Mikael Pezet
- MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Patrick F Chinnery
- MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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20
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Modulating mitochondrial quality in disease transmission: towards enabling mitochondrial DNA disease carriers to have healthy children. Biochem Soc Trans 2017; 44:1091-100. [PMID: 27528757 PMCID: PMC4984448 DOI: 10.1042/bst20160095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Indexed: 12/19/2022]
Abstract
One in 400 people has a maternally inherited mutation in mtDNA potentially causing incurable disease. In so-called heteroplasmic disease, mutant and normal mtDNA co-exist in the cells of carrier women. Disease severity depends on the proportion of inherited abnormal mtDNA molecules. Families who have had a child die of severe, maternally inherited mtDNA disease need reliable information on the risk of recurrence in future pregnancies. However, prenatal diagnosis and even estimates of risk are fraught with uncertainty because of the complex and stochastic dynamics of heteroplasmy. These complications include an mtDNA bottleneck, whereby hard-to-predict fluctuations in the proportions of mutant and normal mtDNA may arise between generations. In ‘mitochondrial replacement therapy’ (MRT), damaged mitochondria are replaced with healthy ones in early human development, using nuclear transfer. We are developing non-invasive alternatives, notably activating autophagy, a cellular quality control mechanism, in which damaged cellular components are engulfed by autophagosomes. This approach could be used in combination with MRT or with the regular management, pre-implantation genetic diagnosis (PGD). Mathematical theory, supported by recent experiments, suggests that this strategy may be fruitful in controlling heteroplasmy. Using mice that are transgenic for fluorescent LC3 (the hallmark of autophagy) we quantified autophagosomes in cleavage stage embryos. We confirmed that the autophagosome count peaks in four-cell embryos and this correlates with a drop in the mtDNA content of the whole embryo. This suggests removal by mitophagy (mitochondria-specific autophagy). We suggest that modulating heteroplasmy by activating mitophagy may be a useful complement to mitochondrial replacement therapy.
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21
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Claeys KG, Abicht A, Häusler M, Kleinle S, Wiesmann M, Schulz JB, Horvath R, Weis J. Novel genetic and neuropathological insights in neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP). Muscle Nerve 2017; 54:328-33. [PMID: 27015314 DOI: 10.1002/mus.25125] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2016] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Neurogenic muscle weakness, ataxia, and retinitis pigmentosa (NARP) is caused by m.8993T>G/C mutations in the mitochondrial adenosine triphosphate synthase subunit 6 gene (MT-ATP6). Traditionally, heteroplasmy levels between 70% and 90% lead to NARP, and >90% result in Leigh syndrome. METHODS In this study we report a 30-year-old man with NARP and m.8993T>G in MT-ATP6. RESULTS Although the patient carried the mutation in homoplasmic state in blood with similarly high levels in urine (94%) and buccal swab (92%), he presented with NARP and not the expected, more severe Leigh phenotype. The mutation could not be detected in any of the 3 analyzed tissues of the mother, indicating a large genetic shift between mother and offspring. Nerve biopsy revealed peculiar endoneurial Schwann cell nuclear accumulations, clusters of concentrically arranged Schwann cells devoid of myelinated axons, and degenerated mitochondria. CONCLUSIONS We emphasize the phenotypic variability of the m.8993T>G MT-ATP6 mutation and the need for caution in predictive counseling in such patients. Muscle Nerve 54: 328-333, 2016.
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Affiliation(s)
- Kristl G Claeys
- Institute of Neuropathology and Department of Neurology, RWTH Aachen University, Aachen, Germany.,Department of Neurology, University Hospitals Leuven and University of Leuven (KU Leuven), Herestraat 49, 3000, Leuven, Belgium
| | | | - Martin Häusler
- Department of Pediatrics, Division of Neuropediatrics and Social Pediatrics, RWTH Aachen University, Aachen, Germany
| | | | - Martin Wiesmann
- Department of Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany
| | - Jörg B Schulz
- Department of Neurology and Jülich Aachen Research Alliance-Translational Brain Medicine, RWTH Aachen University, Aachen, Germany
| | - Rita Horvath
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle upon Tyne, UK
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University, Aachen, Germany
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22
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Replication Errors Made During Oogenesis Lead to Detectable De Novo mtDNA Mutations in Zebrafish Oocytes with a Low mtDNA Copy Number. Genetics 2016; 204:1423-1431. [PMID: 27770035 DOI: 10.1534/genetics.116.194035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/13/2016] [Indexed: 01/30/2023] Open
Abstract
Of all pathogenic mitochondrial DNA (mtDNA) mutations in humans, ∼25% is de novo, although the occurrence in oocytes has never been directly assessed. We used next-generation sequencing to detect point mutations directly in the mtDNA of 3-15 individual mature oocytes and three somatic tissues from eight zebrafish females. Various statistical and biological filters allowed reliable detection of de novo variants with heteroplasmy ≥1.5%. In total, we detected 38 de novo base substitutions, but no insertions or deletions. These 38 de novo mutations were present in 19 of 103 mature oocytes, indicating that ∼20% of the mature oocytes carry at least one de novo mutation with heteroplasmy ≥1.5%. This frequency of de novo mutations is close to that deducted from the reported error rate of polymerase gamma, the mitochondrial replication enzyme, implying that mtDNA replication errors made during oogenesis are a likely explanation. Substantial variation in the mutation prevalence among mature oocytes can be explained by the highly variable mtDNA copy number, since we previously reported that ∼20% of the primordial germ cells have a mtDNA copy number of ≤73 and would lead to detectable mutation loads. In conclusion, replication errors made during oogenesis are an important source of de novo mtDNA base substitutions and their location and heteroplasmy level determine their significance.
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23
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Balasubramaniam S, Lewis B, Mock DM, Said HM, Tarailo-Graovac M, Mattman A, van Karnebeek CD, Thorburn DR, Rodenburg RJ, Christodoulou J. Leigh-Like Syndrome Due to Homoplasmic m.8993T>G Variant with Hypocitrullinemia and Unusual Biochemical Features Suggestive of Multiple Carboxylase Deficiency (MCD). JIMD Rep 2016; 33:99-107. [PMID: 27450367 DOI: 10.1007/8904_2016_559] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 03/09/2016] [Accepted: 03/16/2016] [Indexed: 01/15/2023] Open
Abstract
Leigh syndrome (LS), or subacute necrotizing encephalomyelopathy, is a genetically heterogeneous, relentlessly progressive, devastating neurodegenerative disorder that usually presents in infancy or early childhood. A diagnosis of Leigh-like syndrome may be considered in individuals who do not fulfil the stringent diagnostic criteria but have features resembling Leigh syndrome.We describe a unique presentation of Leigh-like syndrome in a 3-year-old boy with elevated 3-hydroxyisovalerylcarnitine (C5-OH) on newborn screening (NBS). Subsequent persistent plasma elevations of C5-OH and propionylcarnitine (C3) as well as fluctuating urinary markers were suggestive of multiple carboxylase deficiency (MCD). Normal enzymology and mutational analysis of genes encoding holocarboxylase synthetase (HLCS) and biotinidase (BTD) excluded MCD. Biotin uptake studies were normal excluding biotin transporter deficiency. His clinical features at 13 months of age comprised psychomotor delay, central hypotonia, myopathy, failure to thrive, hypocitrullinemia, recurrent episodes of decompensation with metabolic keto-lactic acidosis and an episode of hyperammonemia. Biotin treatment from 13 months of age was associated with increased patient activity, alertness, and attainment of new developmental milestones, despite lack of biochemical improvements. Whole exome sequencing (WES) analysis failed to identify any other variants which could likely contribute to the observed phenotype, apart from the homoplasmic (100%) m.8993T>G variant initially detected by mitochondrial DNA (mtDNA) sequencing.Hypocitrullinemia has been reported in patients with the m.8993T>G variant and other mitochondrial disorders. However, persistent plasma elevations of C3 and C5-OH have previously only been reported in one other patient with this homoplasmic mutation. We suggest considering the m.8993T>G variant early in the diagnostic evaluation of MCD-like biochemical disturbances, particularly when associated with hypocitrullinemia on NBS and subsequent confirmatory tests. An oral biotin trial is also warranted.
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Affiliation(s)
- Shanti Balasubramaniam
- Metabolic Unit, Department of Rheumatology and Metabolic Medicine, Princess Margaret Hospital, Perth, WA, Australia. .,School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia. .,Western Sydney Genetics Program, Children's Hospital at Westmead, Westmead, NSW, Australia.
| | - B Lewis
- PathWest Laboratories WA, Princess Margaret Hospital, Perth, WA, Australia
| | - D M Mock
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - H M Said
- Department of Medicine, University of California School of Medicine Irvine, Irvine, CA, USA
| | - M Tarailo-Graovac
- Centre for Molecular Medicine, Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - A Mattman
- Adult Metabolic Diseases Clinic, Division of Endocrinology and Metabolism, Vancouver General Hospital, UBC, Vancouver, BC, Canada
| | - C D van Karnebeek
- Centre for Molecular Medicine, Department of Pediatrics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - D R Thorburn
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - R J Rodenburg
- Radboud Center for Mitochondrial Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J Christodoulou
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
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24
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Engelstad K, Sklerov M, Kriger J, Sanford A, Grier J, Ash D, Egli D, DiMauro S, Thompson JLP, Sauer MV, Hirano M. Attitudes toward prevention of mtDNA-related diseases through oocyte mitochondrial replacement therapy. Hum Reprod 2016; 31:1058-65. [PMID: 26936885 DOI: 10.1093/humrep/dew033] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 02/07/2016] [Indexed: 12/21/2022] Open
Abstract
STUDY QUESTION Among women who carry pathogenic mitochondrial DNA (mtDNA) point mutations and healthy oocyte donors, what are the levels of support for developing oocyte mitochondrial replacement therapy (OMRT) to prevent transmission of mtDNA mutations? SUMMARY ANSWER The majority of mtDNA carriers and oocyte donors support the development of OMRT techniques to prevent transmission of mtDNA diseases. WHAT IS KNOWN ALREADY Point mutations of mtDNA cause a variety of maternally inherited human diseases that are frequently disabling and often fatal. Recent developments in (OMRT) as well as pronuclear transfer between embryos offer new potential options to prevent transmission of mtDNA disease. However, it is unclear whether the non-scientific community will approve of embryos that contain DNA from three people. STUDY DESIGN, SIZE, DURATION Between 1 June 2012 through 12 February 2015, we administered surveys in cross-sectional studies of 92 female carriers of mtDNA point mutations and 112 healthy oocyte donors. PARTICIPANTS/MATERIALS, SETTING, METHODS The OMRT carrier survey was completed by 92 female carriers of an mtDNA point mutation. Carriers were recruited through the North American Mitochondrial Disease Consortium (NAMDC), the United Mitochondrial Disease Foundation (UMDF), patient support groups, research and private patients followed at the Columbia University Medical Center (CUMC) and patients' referrals of maternal relatives. The OMRT donor survey was completed by 112 women who had donated oocytes through a major ITALIC! in vitro fertilization clinic. MAIN RESULTS AND THE ROLE OF CHANCE All carriers surveyed were aware that they could transmit the mutation to their offspring, with 78% (35/45) of women, who were of childbearing age, indicating that the risk was sufficient to consider not having children, and 95% (87/92) of all carriers designating that the development of this technique was important and worthwhile. Of the 21 surveyed female carriers considering childbearing, 20 (95%) considered having their own biological offspring somewhat or very important and 16 of the 21 respondents (76%) were willing to donate oocytes for research and development. Of 112 healthy oocyte donors who completed the OMRT donor survey, 97 (87%) indicated that they would donate oocytes for generating a viable embryo through OMRT. LIMITATIONS, REASONS FOR CAUTION Many of the participants were either patients or relatives of patients who were already enrolled in a research-oriented database, or who sought care in a tertiary research university setting, indicating a potential sampling bias. The survey was administered to a select group of individuals, who carry, or are at risk for carrying, mtDNA point mutations. These individuals are more likely to have been affected by the mutation or have witnessed first-hand the devastating effects of these mutations. It has not been established whether the general public would be supportive of this work. This survey did not explicitly address alternatives to OMRT. WIDER IMPLICATIONS OF THE FINDINGS This is the first study indicating a high level of interest in the development of these methods among women affected by the diseases or who are at risk of carrying mtDNA mutations as well as willingness of most donors to provide oocytes for the development of OMRT. STUDY FUNDING/COMPETING INTERESTS This work was conducted under the auspices of the NAMDC (Study Protocol 7404). NAMDC (U54NS078059) is part of the NCATS Rare Diseases Clinical Research Network (RDCRN). RDCRN is an initiative of the Office of Rare Diseases Research (ORDR) and NCATS. NAMDC is funded through a collaboration between NCATS, NINDS, NICHD and NIH Office of Dietary Supplements. The work was also supported by the Bernard and Anne Spitzer Fund and the New York Stem Cell Foundation (NYSCF). Dr Hirano has received research support from Santhera Pharmaceuticals and Edison Pharmaceuticals for studies unrelated to this work. None of the other authors have conflicts of interest. TRIAL REGISTRATION NUMBER Not applicable.
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Affiliation(s)
- Kristin Engelstad
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Miriam Sklerov
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Joshua Kriger
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Alexandra Sanford
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Johnston Grier
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Daniel Ash
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Dieter Egli
- Department of Pediatrics, Columbia University Medical Center, New York, NY 10032, USA The New York Stem Cell Foundation Research Institute, New York City, NY 10032, USA
| | - Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - John L P Thompson
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Mark V Sauer
- Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA
| | - Michio Hirano
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
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25
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Wilson IJ, Carling PJ, Alston CL, Floros VI, Pyle A, Hudson G, Sallevelt SCEH, Lamperti C, Carelli V, Bindoff LA, Samuels DC, Wonnapinij P, Zeviani M, Taylor RW, Smeets HJM, Horvath R, Chinnery PF. Mitochondrial DNA sequence characteristics modulate the size of the genetic bottleneck. Hum Mol Genet 2016; 25:1031-41. [PMID: 26740552 PMCID: PMC4754047 DOI: 10.1093/hmg/ddv626] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/22/2015] [Indexed: 01/03/2023] Open
Abstract
With a combined carrier frequency of 1:200, heteroplasmic mitochondrial DNA (mtDNA) mutations cause human disease in ∼1:5000 of the population. Rapid shifts in the level of heteroplasmy seen within a single generation contribute to the wide range in the severity of clinical phenotypes seen in families transmitting mtDNA disease, consistent with a genetic bottleneck during transmission. Although preliminary evidence from human pedigrees points towards a random drift process underlying the shifting heteroplasmy, some reports describe differences in segregation pattern between different mtDNA mutations. However, based on limited observations and with no direct comparisons, it is not clear whether these observations simply reflect pedigree ascertainment and publication bias. To address this issue, we studied 577 mother–child pairs transmitting the m.11778G>A, m.3460G>A, m.8344A>G, m.8993T>G/C and m.3243A>G mtDNA mutations. Our analysis controlled for inter-assay differences, inter-laboratory variation and ascertainment bias. We found no evidence of selection during transmission but show that different mtDNA mutations segregate at different rates in human pedigrees. m.8993T>G/C segregated significantly faster than m.11778G>A, m.8344A>G and m.3243A>G, consistent with a tighter mtDNA genetic bottleneck in m.8993T>G/C pedigrees. Our observations support the existence of different genetic bottlenecks primarily determined by the underlying mtDNA mutation, explaining the different inheritance patterns observed in human pedigrees transmitting pathogenic mtDNA mutations.
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Affiliation(s)
| | - Phillipa J Carling
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research and
| | - Charlotte L Alston
- Wellcome Trust Centre for Mitochondrial Research and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Vasileios I Floros
- Medical Research Council Mitochondrial Biology Unit, Cambridge, UK, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Angela Pyle
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research and
| | - Gavin Hudson
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research and
| | - Suzanne C E H Sallevelt
- Department of Clinical Genetics, Research Schools GROW/CARIM, Maastricht University Medical Center, Maastricht, Netherlands
| | - Costanza Lamperti
- Division of Molecular Neurogenetics, National Neurological Institute 'C. Besta', Milano, Italy
| | - Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy, Unit of Neurology, Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Laurence A Bindoff
- Department of Neurology, Haukeland University Hospital, Bergen, Norway, Department of Clinical Medicine (K1), University of Bergen, Bergen, Norway
| | - David C Samuels
- Vanderbilt Genetics Institute, Department of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, TN, USA and
| | - Passorn Wonnapinij
- Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Massimo Zeviani
- Medical Research Council Mitochondrial Biology Unit, Cambridge, UK, Division of Molecular Neurogenetics, National Neurological Institute 'C. Besta', Milano, Italy
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research and Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Hubert J M Smeets
- Department of Clinical Genetics, Research Schools GROW/CARIM, Maastricht University Medical Center, Maastricht, Netherlands
| | - Rita Horvath
- Institute of Genetic Medicine, Wellcome Trust Centre for Mitochondrial Research and
| | - Patrick F Chinnery
- Wellcome Trust Centre for Mitochondrial Research and Medical Research Council Mitochondrial Biology Unit, Cambridge, UK, Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge, UK,
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26
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Smeets HJ, Sallevelt SC, Dreesen JC, de Die-Smulders CE, de Coo IF. Preventing the transmission of mitochondrial DNA disorders using prenatal or preimplantation genetic diagnosis. Ann N Y Acad Sci 2015; 1350:29-36. [DOI: 10.1111/nyas.12866] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Hubert J.M. Smeets
- Department of Clinical Genetics; Maastricht University Medical Centre; Maastricht the Netherlands
- CARIM School for Cardiovascular Diseases; Maastricht University; Maastricht the Netherlands
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht the Netherlands
| | - Suzanne C.E.H. Sallevelt
- Department of Clinical Genetics; Maastricht University Medical Centre; Maastricht the Netherlands
- CARIM School for Cardiovascular Diseases; Maastricht University; Maastricht the Netherlands
| | - Jos C.F.M. Dreesen
- Department of Clinical Genetics; Maastricht University Medical Centre; Maastricht the Netherlands
| | - Christine E.M. de Die-Smulders
- Department of Clinical Genetics; Maastricht University Medical Centre; Maastricht the Netherlands
- GROW School for Oncology and Developmental Biology; Maastricht University; Maastricht the Netherlands
| | - Irenaeus F.M. de Coo
- Department of Neurology; Erasmus MC-Sophia Children's Hospital; Rotterdam the Netherlands
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27
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Otten ABC, Smeets HJM. Evolutionary defined role of the mitochondrial DNA in fertility, disease and ageing. Hum Reprod Update 2015; 21:671-89. [PMID: 25976758 DOI: 10.1093/humupd/dmv024] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 04/22/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The endosymbiosis of an alpha-proteobacterium and a eubacterium a billion years ago paved the way for multicellularity and enabled eukaryotes to flourish. The selective advantage for the host was the acquired ability to generate large amounts of intracellular hydrogen-dependent adenosine triphosphate. The price was increased reactive oxygen species (ROS) inside the eukaryotic cell, causing high mutation rates of the mitochondrial DNA (mtDNA). According to the Muller's ratchet theory, this accumulation of mutations in asexually transmitted mtDNA would ultimately lead to reduced reproductive fitness and eventually extinction. However, mitochondria have persisted over the course of evolution, initially due to a rapid, extreme evolutionary reduction of the mtDNA content. After the phylogenetic divergence of eukaryotes into animals, fungi and plants, differences in evolution of the mtDNA occurred with different adaptations for coping with the mutation burden within these clades. As a result, mitochondrial evolutionary mechanisms have had a profound effect on human adaptation, fertility, healthy reproduction, mtDNA disease manifestation and transmission and ageing. An understanding of these mechanisms might elucidate novel approaches for treatment and prevention of mtDNA disease. METHODS The scientific literature was investigated to determine how mtDNA evolved in animals, plants and fungi. Furthermore, the different mechanisms of mtDNA inheritance and of balancing Muller's ratchet in these species were summarized together with the consequences of these mechanisms for human health and reproduction. RESULTS Animal, plant and fungal mtDNA have evolved differently. Animals have compact genomes, little recombination, a stable number of genes and a high mtDNA copy number, whereas plants have larger genomes with variable gene counts, a low mtDNA copy number and many recombination events. Fungal mtDNA is somewhere in between. In plants, the mtDNA mutation rate is kept low by effective ROS defence and efficient recombination-mediated mtDNA repair. In animal mtDNA, these mechanisms are not or less well-developed and the detrimental mutagenesis events are controlled by a high mtDNA copy number in combination with a genetic bottleneck and purifying selection during transmission. The mtDNA mutation rates in animals are higher than in plants, which allow mobile animals to adapt more rapidly to various environmental conditions in terms of energy production, whereas static plants do not have this need. Although at the level of the species, these mechanisms have been extremely successful, they can have adverse effects for the individual, resulting, in humans, in severe or unpredictably segregating mtDNA diseases, as well as fertility problems and unhealthy ageing. CONCLUSIONS Understanding the forces and processes that underlie mtDNA evolution among different species increases our knowledge on the detrimental consequences that individuals can have from these evolutionary end-points. Alternative outcomes in animals, fungi and plants will lead to a better understanding of the inheritance of mtDNA disorders and mtDNA-related fertility problems. These will allow the development of options to ameliorate, cure and/or prevent mtDNA diseases and mtDNA-related fertility problems.
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Affiliation(s)
- Auke B C Otten
- Department of Clinical Genetics, Unit Clinical Genomics, Maastricht University Medical Centre, PO box 616 (box 16), 6200 MD Maastricht, The Netherlands School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Hubert J M Smeets
- Department of Clinical Genetics, Unit Clinical Genomics, Maastricht University Medical Centre, PO box 616 (box 16), 6200 MD Maastricht, The Netherlands School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre, Maastricht, The Netherlands
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28
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Steffann J, Monnot S, Bonnefont JP. mtDNA mutations variously impact mtDNA maintenance throughout the human embryofetal development. Clin Genet 2015; 88:416-24. [PMID: 25523230 DOI: 10.1111/cge.12557] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/08/2014] [Accepted: 12/16/2014] [Indexed: 12/31/2022]
Abstract
Mitochondria are the largest generator of ATP in the cell. It is therefore expected that energy-requiring processes such as oocyte maturation, early embryonic or fetal development, would be adversely impacted in case of mitochondrial deficiency. Human mitochondrial DNA (mtDNA) mutations constitute a spontaneous model of mitochondrial failure and offer the opportunity to study the consequences of energetic defects over fertility and embryofetal development. This review provides an update on the mtDNA metabolism in the early preimplantation embryo, and compiles data showing the impact of mtDNA mutations over mtDNA segregation. Despite convincing evidences about the essential role of mitochondria in oogenesis and preimplantation development, no correlation between the presence of a mtDNA mutation and fertilization failure, impaired oocyte quality, or embryofetal development arrest was found. In some cases, mutant cells might upregulate their mitochondrial content to overcome the bioenergetic defects induced by mtDNA mutations, and might escape negative selection. Finally we discuss some of the clinical consequences of these observations.
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Affiliation(s)
- J Steffann
- Université Paris-Descartes, Sorbonne Paris Cité, Institut Imagine and INSERM U1163, Hôpital Necker-Enfants Malades, Paris, France
| | - S Monnot
- Université Paris-Descartes, Sorbonne Paris Cité, Institut Imagine and INSERM U1163, Hôpital Necker-Enfants Malades, Paris, France
| | - J-P Bonnefont
- Université Paris-Descartes, Sorbonne Paris Cité, Institut Imagine and INSERM U1163, Hôpital Necker-Enfants Malades, Paris, France
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29
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Burgstaller JP, Johnston IG, Poulton J. Mitochondrial DNA disease and developmental implications for reproductive strategies. Mol Hum Reprod 2014; 21:11-22. [PMID: 25425607 PMCID: PMC4275042 DOI: 10.1093/molehr/gau090] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial diseases are potentially severe, incurable diseases resulting from dysfunctional mitochondria. Several important mitochondrial diseases are caused by mutations in mitochondrial DNA (mtDNA), the genetic material contained within mitochondria, which is maternally inherited. Classical and modern therapeutic approaches exist to address the inheritance of mtDNA disease, but are potentially complicated by the fact that cellular mtDNA populations evolve according to poorly-understood dynamics during development and organismal lifetimes. We review these therapeutic approaches and models of mtDNA dynamics during development, and discuss the implications of recent results from these models for modern mtDNA therapies. We particularly highlight mtDNA segregation—differences in proliferative rates between different mtDNA haplotypes—as a potential and underexplored issue in such therapies. However, straightforward strategies exist to combat this and other potential therapeutic problems. In particular, we describe haplotype matching as an approach with the power to potentially ameliorate any expected issues from mtDNA incompatibility.
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Affiliation(s)
- Joerg Patrick Burgstaller
- Biotechnology in Animal Production, Department for Agrobiotechnology, IFA Tulln, 3430 Tulln, Austria Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Iain G Johnston
- Department of Mathematics, Imperial College London, London SW7 2AZ, UK
| | - Joanna Poulton
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford OX3 9DU, UK
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30
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Heindryckx B, Neupane J, Vandewoestyne M, Christodoulou C, Jackers Y, Gerris J, Van den Abbeel E, Van Coster R, Deforce D, De Sutter P. Mutation-free baby born from a mitochondrial encephalopathy, lactic acidosis and stroke-like syndrome carrier after blastocyst trophectoderm preimplantation genetic diagnosis. Mitochondrion 2014; 18:12-7. [DOI: 10.1016/j.mito.2014.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 08/18/2014] [Accepted: 08/18/2014] [Indexed: 01/01/2023]
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31
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Regulation of mitochondrial genome inheritance by autophagy and ubiquitin-proteasome system: implications for health, fitness, and fertility. BIOMED RESEARCH INTERNATIONAL 2014; 2014:981867. [PMID: 25028670 PMCID: PMC4083708 DOI: 10.1155/2014/981867] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 04/01/2014] [Accepted: 04/07/2014] [Indexed: 01/07/2023]
Abstract
Mitochondria, the energy-generating organelles, play a role in numerous cellular functions including adenosine triphosphate (ATP) production, cellular homeostasis, and apoptosis. Maternal inheritance of mitochondria and mitochondrial DNA (mtDNA) is universally observed in humans and most animals. In general, high levels of mitochondrial heteroplasmy might contribute to a detrimental effect on fitness and disease resistance. Therefore, a disposal of the sperm-derived mitochondria inside fertilized oocytes assures normal preimplantation embryo development. Here we summarize the current research and knowledge concerning the role of autophagic pathway and ubiquitin-proteasome-dependent proteolysis in sperm mitophagy in mammals, including humans. Current data indicate that sperm mitophagy inside the fertilized oocyte could occur along multiple degradation routes converging on autophagic clearance of paternal mitochondria. The influence of assisted reproductive therapies (ART) such as intracytoplasmic sperm injection (ICSI), mitochondrial replacement (MR), and assisted fertilization of oocytes from patients of advanced reproductive age on mitochondrial function, inheritance, and fitness and for the development and health of ART babies will be of particular interest to clinical audiences. Altogether, the study of sperm mitophagy after fertilization has implications in the timing of evolution and developmental and reproductive biology and in human health, fitness, and management of mitochondrial disease.
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Pallotti F, Binelli G, Fabbri R, Valentino ML, Vicenti R, Macciocca M, Cevoli S, Baruzzi A, DiMauro S, Carelli V. A wide range of 3243A>G/tRNALeu(UUR) (MELAS) mutation loads may segregate in offspring through the female germline bottleneck. PLoS One 2014; 9:e96663. [PMID: 24805791 PMCID: PMC4013013 DOI: 10.1371/journal.pone.0096663] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 04/10/2014] [Indexed: 12/19/2022] Open
Abstract
Segregation of mutant mtDNA in human tissues and through the germline is debated, with no consensus about the nature and size of the bottleneck hypothesized to explain rapid generational shifts in mutant loads. We investigated two maternal lineages with an apparently different inheritance pattern of the same pathogenic mtDNA 3243A>G/tRNALeu(UUR) (MELAS) mutation. We collected blood cells, muscle biopsies, urinary epithelium and hair follicles from 20 individuals, as well as oocytes and an ovarian biopsy from one female mutation carrier, all belonging to the two maternal lineages to assess mutant mtDNA load, and calculated the theoretical germline bottleneck size (number of segregating units). We also evaluated “mother-to-offspring” segregations from the literature, for which heteroplasmy assessment was available in at least three siblings besides the proband. Our results showed that mutation load was prevalent in skeletal muscle and urinary epithelium, whereas in blood cells there was an inverse correlation with age, as previously reported. The histoenzymatic staining of the ovarian biopsy failed to show any cytochrome-c-oxidase defective oocyte. Analysis of four oocytes and one offspring from the same unaffected mother of the first family showed intermediate heteroplasmic mutant loads (10% to 75%), whereas very skewed loads of mutant mtDNA (0% or 81%) were detected in five offspring of another unaffected mother from the second family. Bottleneck size was 89 segregating units for the first mother and 84 for the second. This was remarkably close to 88, the number of “segregating units” in the “mother-to-offspring” segregations retrieved from literature. In conclusion, a wide range of mutant loads may be found in offspring tissues and oocytes, resulting from a similar theoretical bottleneck size.
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Affiliation(s)
- Francesco Pallotti
- Department of Neurology, Columbia University, New York City, New York, United States of America
- Dipartimento di Scienze Chirurgiche e Morfologiche, University of Insubria, Varese, Italy
| | - Giorgio Binelli
- Dipartimento di Scienze Teoriche e Applicate, University of Insubria, Varese, Italy
| | - Raffaella Fabbri
- Unità Operativa di Ginecologia e Fisiopatologia della Riproduzione Umana, Ospedale S.Orsola-Malpighi, University of Bologna, Bologna, Italy
- Dipartimento di Scienze Mediche e Chirurgiche (DIMEC), University of Bologna, Bologna, Italy
| | - Maria L. Valentino
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy
- Dipartimento di Scienze Biomediche e Neuromotorie (DIBINEM), University of Bologna, Bologna, Italy
| | - Rossella Vicenti
- Unità Operativa di Ginecologia e Fisiopatologia della Riproduzione Umana, Ospedale S.Orsola-Malpighi, University of Bologna, Bologna, Italy
- Dipartimento di Scienze Mediche e Chirurgiche (DIMEC), University of Bologna, Bologna, Italy
| | - Maria Macciocca
- Unità Operativa di Ginecologia e Fisiopatologia della Riproduzione Umana, Ospedale S.Orsola-Malpighi, University of Bologna, Bologna, Italy
- Dipartimento di Scienze Mediche e Chirurgiche (DIMEC), University of Bologna, Bologna, Italy
| | - Sabina Cevoli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy
- Dipartimento di Scienze Biomediche e Neuromotorie (DIBINEM), University of Bologna, Bologna, Italy
| | - Agostino Baruzzi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy
- Dipartimento di Scienze Biomediche e Neuromotorie (DIBINEM), University of Bologna, Bologna, Italy
| | - Salvatore DiMauro
- Department of Neurology, Columbia University, New York City, New York, United States of America
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, Bologna, Italy
- Dipartimento di Scienze Biomediche e Neuromotorie (DIBINEM), University of Bologna, Bologna, Italy
- * E-mail:
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Neupane J, Vandewoestyne M, Heindryckx B, Ghimire S, Lu Y, Qian C, Lierman S, Van Coster R, Gerris J, Deroo T, Deforce D, De Sutter P. A systematic analysis of the suitability of preimplantation genetic diagnosis for mitochondrial diseases in a heteroplasmic mitochondrial mouse model. Hum Reprod 2014; 29:852-9. [DOI: 10.1093/humrep/deu016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Rambags BPB, van Boxtel DCJ, Tharasanit T, Lenstra JA, Colenbrander B, Stout TAE. Advancing maternal age predisposes to mitochondrial damage and loss during maturation of equine oocytes in vitro. Theriogenology 2014; 81:959-65. [PMID: 24576711 DOI: 10.1016/j.theriogenology.2014.01.020] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 01/08/2014] [Accepted: 01/16/2014] [Indexed: 01/09/2023]
Abstract
In many mammalian species, reproductive success decreases with maternal age. One proposed contributor to this age-related decrease in fertility is a reduction in the quantity or functionality of mitochondria in oocytes. This study examined whether maternal age or (in vitro maturation). IVM affect the quantity of mitochondria in equine oocytes. Oocytes were collected from the ovaries of slaughtered mares categorized as young (<12 years) or aged (≥12 years) and either denuded and prepared for analysis immediately (not-IVM) or matured in vitro for 30 hours before preparation (IVM). The mean oocyte mitochondrial DNA copy number was estimated by quantitative polymerase chain reaction and found to be significantly lower in oocytes from aged mares and that had been subjected to IVM than in any other group. Transmission electron microscopy demonstrated that mitochondria in aged mare oocytes subjected to IVM experienced significantly more swelling and loss of cristae than in other groups. We conclude that maternal aging is associated with a heightened susceptibility to mitochondrial damage and loss in equine oocytes, which manifests during IVM. This predisposition to mitochondrial degeneration probably contributes to reduced fertility in aged mares.
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Affiliation(s)
- B P B Rambags
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584 CM Utrecht, The Netherlands
| | - D C J van Boxtel
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584 CM Utrecht, The Netherlands
| | - T Tharasanit
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584 CM Utrecht, The Netherlands
| | - J A Lenstra
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584 CM Utrecht, The Netherlands
| | - B Colenbrander
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584 CM Utrecht, The Netherlands
| | - T A E Stout
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584 CM Utrecht, The Netherlands.
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Wallace DC, Chalkia D. Mitochondrial DNA genetics and the heteroplasmy conundrum in evolution and disease. Cold Spring Harb Perspect Biol 2013; 5:a021220. [PMID: 24186072 PMCID: PMC3809581 DOI: 10.1101/cshperspect.a021220] [Citation(s) in RCA: 415] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The unorthodox genetics of the mtDNA is providing new perspectives on the etiology of the common "complex" diseases. The maternally inherited mtDNA codes for essential energy genes, is present in thousands of copies per cell, and has a very high mutation rate. New mtDNA mutations arise among thousands of other mtDNAs. The mechanisms by which these "heteroplasmic" mtDNA mutations come to predominate in the female germline and somatic tissues is poorly understood, but essential for understanding the clinical variability of a range of diseases. Maternal inheritance and heteroplasmy also pose major challengers for the diagnosis and prevention of mtDNA disease.
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Affiliation(s)
- Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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St John J. The control of mtDNA replication during differentiation and development. Biochim Biophys Acta Gen Subj 2013; 1840:1345-54. [PMID: 24183916 DOI: 10.1016/j.bbagen.2013.10.036] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND Mitochondrial DNA (mtDNA) is important for energy production as it encodes some of the key genes of electron transfer chain, where the majority of cellular energy is generated through oxidative phosphorylation (OXPHOS). MtDNA replication is mediated by nuclear DNA-encoded proteins or enzymes, which translocate to the mitochondria, and is strictly regulated throughout development. It starts with approximately 200 copies in each primordial germ cell and these copies undergo expansion and restriction events at various stages of development. SCOPE OF REVIEW I describe the patterns of mtDNA replication at key stages of development. I explain that it is essential to regulate mtDNA copy number and to establish the mtDNA set point in order that the mature, specialised cell acquires the appropriate numbers of mtDNA copy to generate sufficient adenosine triphosphate (ATP) through OXPHOS to undertake its specialised function. I discuss how these processes are dependent on the controlled expression of the nuclear-encoded mtDNA-specific replication factors and that this can be modulated by mtDNA haplotypes. I discuss how these events are altered by certain assisted reproductive technologies, some of which have been proposed to prevent the transmission of mutant mtDNA and others to overcome infertility. Furthermore, some of these technologies are predisposed to transmitting two or more populations of mtDNA, which can be extremely harmful. MAJOR CONCLUSIONS The failure to regulate mtDNA replication and mtDNA transmission during development is disadvantageous. GENERAL SIGNIFICANCE Manipulation of oocytes and embryos can lead to significant implications for the maternal-only transmission of mtDNA. This article is part of a Special Issue entitled Frontiers of mitochondrial research.
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Affiliation(s)
- Justin St John
- Mitochondrial Genetics Group, Centre for Genetic Diseases, Monash Institute of Medical Research, Monash University, 27-31 Wright Street, Clayton, Victoria 3168, Australia.
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Affiliation(s)
- Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, New York
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Smeets HJM. Preventing the transmission of mitochondrial DNA disorders: selecting the good guys or kicking out the bad guys. Reprod Biomed Online 2013; 27:599-610. [PMID: 24135157 DOI: 10.1016/j.rbmo.2013.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 07/26/2013] [Accepted: 08/01/2013] [Indexed: 01/30/2023]
Abstract
Mitochondrial disorders represent the most common group of inborn errors of metabolism. Clinical manifestations can be extremely variable, ranging from single affected tissues to multisystemic syndromes. Maternally inherited mitochondrial DNA (mtDNA) mutations are a frequent cause, affecting about one in 5000 individuals. The expression of mtDNA mutations differs from nuclear gene defects. Mutations are either homoplasmic or heteroplasmic, and in the latter case disease becomes manifest when the mutation load exceeds a tissue-specific threshold. Mutation load can vary between tissues and in time, and often an exact correlation between mutation load and clinical manifestations is lacking. Because of the possible clinical severity, the lack of treatment and the high recurrence risk of affected offspring for female carriers, couples request prevention of transmission of mtDNA mutations. Previously, choices have been limited due to a segregational bottleneck, which makes the mtDNA mutation load in embryos highly variable and the consequences largely unpredictable. However, recently it was shown that preimplantation genetic diagnosis offers a fair chance of unaffected offspring to carriers of heteroplasmic mtDNA mutations. Technically and ethically challenging possibilities, such maternal spindle transfer and pronuclear transfer, are emerging and providing carriers additional prospects of giving birth to a healthy child.
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Affiliation(s)
- Hubert J M Smeets
- Unit Clinical Genomics, Department of Genetics and Cell Biology, School for Growth and Development and for Cardiovascular Research, Maastricht University Medical Centre, Maastricht, The Netherlands.
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Lombès A, Auré K, Bellanné-Chantelot C, Gilleron M, Jardel C. Unsolved issues related to human mitochondrial diseases. Biochimie 2013; 100:171-6. [PMID: 23973280 DOI: 10.1016/j.biochi.2013.08.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/10/2013] [Indexed: 12/21/2022]
Abstract
Human mitochondrial diseases, defined as the diseases due to a mitochondrial oxidative phosphorylation defect, represent a large group of very diverse diseases with respect to phenotype and genetic causes. They present with many unsolved issues, the comprehensive analysis of which is beyond the scope of this review. We here essentially focus on the mechanisms underlying the diversity of targeted tissues, which is an important component of the large panel of these diseases phenotypic expression. The reproducibility of genotype/phenotype expression, the presence of modifying factors, and the potential causes for the restricted pattern of tissular expression are reviewed. Special emphasis is made on heteroplasmy, a specific feature of mitochondrial diseases, defined as the coexistence within the cell of mutant and wild type mitochondrial DNA molecules. Its existence permits unequal segregation during mitoses of the mitochondrial DNA populations and consequently heterogeneous tissue distribution of the mutation load. The observed tissue distributions of recurrent human mitochondrial DNA deleterious mutations are diverse but reproducible for a given mutation demonstrating that the segregation is not a random process. Its extent and mechanisms remain essentially unknown despite recent advances obtained in animal models.
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Affiliation(s)
- Anne Lombès
- Inserm Institut Cochin U1016, CNRS UMR 8104, 24 rue du Fb St Jacques, Paris F-75014, France; Université Paris-Descartes-Paris5, Paris F-75014, France; AP-HP, Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, GHU Pitié-Salpêtrière, Paris F-75651, France.
| | - Karine Auré
- Inserm Institut Cochin U1016, CNRS UMR 8104, 24 rue du Fb St Jacques, Paris F-75014, France; AP-HP, Hôpital Ambroise Paré, Service d'explorations fonctionnelles, Boulogne-Billancourt F-92100, France; Université Versailles-Saint-Quentin en Yvelines, Faculté de Médecine, F-78180, France.
| | - Christine Bellanné-Chantelot
- AP-HP, Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, GHU Pitié-Salpêtrière, Paris F-75651, France.
| | - Mylène Gilleron
- Inserm Institut Cochin U1016, CNRS UMR 8104, 24 rue du Fb St Jacques, Paris F-75014, France; AP-HP, Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, GHU Pitié-Salpêtrière, Paris F-75651, France.
| | - Claude Jardel
- Inserm Institut Cochin U1016, CNRS UMR 8104, 24 rue du Fb St Jacques, Paris F-75014, France; AP-HP, Service de Biochimie Métabolique et Centre de Génétique moléculaire et chromosomique, GHU Pitié-Salpêtrière, Paris F-75651, France.
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Kasashima K, Nagao Y, Endo H. Dynamic regulation of mitochondrial genome maintenance in germ cells. Reprod Med Biol 2013; 13:11-20. [PMID: 24482608 PMCID: PMC3890057 DOI: 10.1007/s12522-013-0162-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/04/2013] [Indexed: 12/11/2022] Open
Abstract
Mitochondria play a crucial role in the development and function of germ cells. Mitochondria contain a maternally inherited genome that should be transmitted to offspring without reactive oxygen species‐induced damage during germ line development. Germ cells are also involved in the mitochondrial DNA (mtDNA) bottleneck; thus, the appropriate regulation of mtDNA in these cells is very important for this characteristic transmission. In this review, we focused on unique regulation of the mitochondrial genome in animal germ cells; paternal elimination and the mtDNA bottleneck in females. We also summarized the mitochondrial nucleoid factors involved in various mtDNA regulation pathways. Among them, mitochondrial transcription factor A (TFAM), which has pleiotropic and essential roles in mtDNA maintenance, appears to have putative roles in germ cell regulation.
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Affiliation(s)
- Katsumi Kasashima
- Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
| | - Yasumitsu Nagao
- Center for Experimental Medicine, Jichi Medical University, Shimotsuke, Tochigi 329-0498 Japan
| | - Hitoshi Endo
- Department of Biochemistry, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498 Japan
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Shanske S, Naini A, Chmait RH, Akman HO, Mansukhani M, Lu J, Hirano M, DiMauro S. Mutation in an mtDNA protein-coding gene: prenatal diagnosis aided by fetal muscle biopsy. J Child Neurol 2013; 28:264-8. [PMID: 22532554 PMCID: PMC3959766 DOI: 10.1177/0883073812441067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Prenatal diagnosis of disorders due to mitochondrial DNA (mtDNA) tRNA gene mutations is problematic. Experience in families harboring the protein-coding ATPase 6 m.8993T>G mutation suggests that the mutant load is homogeneous in different tissues, thus allowing prenatal diagnosis. We have encountered a novel protein-coding gene mutation, m.10198C>T in MT-ND3. A baby girl homoplasmic for this mutation died at 3 months after severe psychomotor regression and respiratory arrest. The mother had no detectable mutation in accessible tissues. The product of a second pregnancy showed only wild-type mt genomes in amniocytes, chorionic villi, and biopsied fetal muscle. This second girl is now 18 months old and healthy. Our observations support the concept that the pathogenic mutation in this patient appeared de novo and that fetal muscle biopsy is a useful aide in prenatal diagnosis.
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Affiliation(s)
- Sara Shanske
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Ali Naini
- Department of Neurology, Columbia University Medical Center, New York, NY, USA,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Ramen H. Chmait
- Department of Obstetrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Hasan O. Akman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Mahesh Mansukhani
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Jiesheng Lu
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Michio Hirano
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Salvatore DiMauro
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
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Pearce S, Nezich CL, Spinazzola A. Mitochondrial diseases: translation matters. Mol Cell Neurosci 2012; 55:1-12. [PMID: 22986124 DOI: 10.1016/j.mcn.2012.08.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 08/22/2012] [Accepted: 08/25/2012] [Indexed: 11/30/2022] Open
Abstract
Mitochondrial diseases comprise a heterogeneous group of disorders characterized by compromised energy production. Since the early days of mitochondrial medical genetics, it has been known that these can be caused by defects in mitochondrial protein synthesis. However, only in recent years have we begun to develop a broader picture of the array of proteins required for mitochondrial translation. With this new knowledge has come the realization that there are many more neurological and other, diseases attributable to impaired mitochondrial translation than previously thought. Perturbation of any part of this intricate machinery, from the primary sequence of transfer or ribosomal RNAs, to the proteolytic processing of ribosomal proteins, can cause mitochondrial dysfunction and disease. In this review we discuss the current understanding of the mechanisms and factors involved in mammalian mitochondrial translation, and the diverse pathologies resulting when it malfunctions. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Sarah Pearce
- MRC Mitochondrial Biology Unit, Wellcome Trust-MRC Building, Hills Road Cambridge, CB2 0XY, UK
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Henriques M, Diogo L, Garcia P, Pratas J, Simões M, Grazina M. Mitochondrial DNA 8993T>G mutation in a child with ornithine transcarbamylase deficiency and leigh syndrome: an unexpected association. J Child Neurol 2012; 27:1059-61. [PMID: 22241703 DOI: 10.1177/0883073811431015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
MC, female, is the third child of a nonconsanguineous Portuguese couple, born after an uneventful pregnancy and delivery. A positive family history of ornithine transcarbamylase deficiency, associated with the IVS8+1 G>A mutation in the ornithine transcarbamylase gene, prompted prenatal diagnosis with identification of the same mutation in the proband. During an episode of Klebsiella pneumoniae sepsis at 1.5 months of age, lactic acidosis and moderate hyperammonemia were noticed. After a short asymptomatic period, progressive neurologic symptoms, with normal ammonemia, persistent hyperlactacidemia, and typical lesions in brain computed tomography (CT) scan led to a diagnosis of Leigh syndrome. Mitochondrial respiratory chain complex V was reduced in the liver. The mtDNA 8993T>G mutation was identified in the liver, muscle, and blood (82%-87% heteroplasmy). She died at 6 months of age. This case represents a benign phenotype of ornithine transcarbamylase deficiency, associated with a severe mitochondrial respiratory chain disorder due to an mtDNA pathogenic mutation.
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Affiliation(s)
- Margarida Henriques
- Centro de Desenvolvimento Dr Luís Borges, Hospital Pediátrico de Coimbra, CHC, Coimbra, Portugal
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44
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Transmission, inheritance and replication of mitochondrial DNA in mammals: implications for reproductive processes and infertility. Cell Tissue Res 2012; 349:795-808. [DOI: 10.1007/s00441-012-1444-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 04/26/2012] [Indexed: 01/03/2023]
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Hellebrekers D, Wolfe R, Hendrickx A, de Coo I, de Die C, Geraedts J, Chinnery P, Smeets H. PGD and heteroplasmic mitochondrial DNA point mutations: a systematic review estimating the chance of healthy offspring. Hum Reprod Update 2012; 18:341-9. [DOI: 10.1093/humupd/dms008] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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46
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Jonckheere AI, Smeitink JAM, Rodenburg RJT. Mitochondrial ATP synthase: architecture, function and pathology. J Inherit Metab Dis 2012; 35:211-25. [PMID: 21874297 PMCID: PMC3278611 DOI: 10.1007/s10545-011-9382-9] [Citation(s) in RCA: 364] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 07/22/2011] [Accepted: 07/27/2011] [Indexed: 12/16/2022]
Abstract
Human mitochondrial (mt) ATP synthase, or complex V consists of two functional domains: F(1), situated in the mitochondrial matrix, and F(o), located in the inner mitochondrial membrane. Complex V uses the energy created by the proton electrochemical gradient to phosphorylate ADP to ATP. This review covers the architecture, function and assembly of complex V. The role of complex V di-and oligomerization and its relation with mitochondrial morphology is discussed. Finally, pathology related to complex V deficiency and current therapeutic strategies are highlighted. Despite the huge progress in this research field over the past decades, questions remain to be answered regarding the structure of subunits, the function of the rotary nanomotor at a molecular level, and the human complex V assembly process. The elucidation of more nuclear genetic defects will guide physio(patho)logical studies, paving the way for future therapeutic interventions.
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Affiliation(s)
- An I. Jonckheere
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, 656 Laboratory for Genetic, Endocrine, and Metabolic Disorders, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Jan A. M. Smeitink
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, 656 Laboratory for Genetic, Endocrine, and Metabolic Disorders, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Richard J. T. Rodenburg
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, 656 Laboratory for Genetic, Endocrine, and Metabolic Disorders, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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47
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Monnot S, Gigarel N, Samuels DC, Burlet P, Hesters L, Frydman N, Frydman R, Kerbrat V, Funalot B, Martinovic J, Benachi A, Feingold J, Munnich A, Bonnefont JP, Steffann J. Segregation of mtDNA throughout human embryofetal development: m.3243A>G as a model system. Hum Mutat 2011; 32:116-25. [PMID: 21120938 PMCID: PMC3058134 DOI: 10.1002/humu.21417] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mitochondrial DNA (mtDNA) mutations cause a wide range of serious diseases with high transmission risk and maternal inheritance. Tissue heterogeneity of the heteroplasmy rate (“mutant load”) accounts for the wide phenotypic spectrum observed in carriers. Owing to the absence of therapy, couples at risk to transmit such disorders commonly ask for prenatal (PND) or preimplantation diagnosis (PGD). The lack of data regarding heteroplasmy distribution throughout intrauterine development, however, hampers the implementation of such procedures. We tracked the segregation of the m.3243A > G mutation (MT-TL1 gene) responsible for the MELAS syndrome in the developing embryo/fetus, using tissues and cells from eight carrier females, their 38 embryos and 12 fetuses. Mutant mtDNA segregation was found to be governed by random genetic drift, during oogenesis and somatic tissue development. The size of the bottleneck operating for m.3243A > G during oogenesis was shown to be individual-dependent. Comparison with data we achieved for the m.8993T > G mutation (MT-ATP6 gene), responsible for the NARP/Leigh syndrome, indicates that these mutations differentially influence mtDNA segregation during oogenesis, while their impact is similar in developing somatic tissues. These data have major consequences for PND and PGD procedures in mtDNA inherited disorders. Hum Mutat 32:116–125, 2011. © 2010 Wiley-Liss, Inc.
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Affiliation(s)
- Sophie Monnot
- Université Paris-Descartes, Unité INSERM U, Hopital Necker-Enfants Malades, France
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The awakening of an advanced malignant cancer: an insult to the mitochondrial genome. Biochim Biophys Acta Gen Subj 2011; 1820:652-62. [PMID: 21920409 DOI: 10.1016/j.bbagen.2011.08.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 08/26/2011] [Accepted: 08/29/2011] [Indexed: 02/08/2023]
Abstract
BACKGROUND In only months-to-years a primary cancer can progress to an advanced phenotype that is metastatic and resistant to clinical treatments. As early as the 1900s, it was discovered that the progression of a cancer to the advanced phenotype is often associated with a shift in the metabolic profile of the disease from a state of respiration to anaerobic fermentation - a phenomenon denoted as the Warburg Effect. SCOPE OF REVIEW Reports in the literature strongly suggest that the Warburg Effect is generated as a response to a loss in the integrity of the sequence and/or copy number of the mitochondrial genome content within a cancer. MAJOR CONCLUSIONS Multiple studies regarding the progression of cancer indicate that mutation, and/or, a flux in the copy number, of the mitochondrial genome content can support the early development of a cancer, until; the mutational load and/or the reduction-to-depletion of the copy number of the mitochondrial genome content induces the progression of the disease to an advanced phenotype. GENERAL SIGNIFICANCE Collectively, evidence has revealed that the human cell has incorporated the mitochondrial genome content into a cellular mechanism that, when pathologically actuated, can de(un)differentiate a cancer from the parental tissue of origin into an autonomous disease that disrupts the hierarchical structure-and-function of the human body. This article is part of a Special Issue entitled: Biochemistry of Mitochondria.
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Chiaratti MR, Meirelles FV, Wells D, Poulton J. Therapeutic treatments of mtDNA diseases at the earliest stages of human development. Mitochondrion 2011; 11:820-8. [DOI: 10.1016/j.mito.2010.11.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 11/29/2010] [Indexed: 11/25/2022]
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Spinazzola A. Mitochondrial DNA mutations and depletion in pediatric medicine. Semin Fetal Neonatal Med 2011; 16:190-6. [PMID: 21652274 DOI: 10.1016/j.siny.2011.04.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are a group of diseases traditionally ascribed to defects of the respiratory chain, which is the only metabolic pathway in the cell that is under the control of the two separate genetic systems, the mitochondrial genome (mtDNA) and the nuclear genome (nDNA). Therefore the genetic classification of the primary mitochondrial diseases distinguishes disorders due to mutations in mtDNA, which are sporadic or maternal inherited, from disorders due to mutations in nDNA, which are governed by the stricter rules of mendelian genetics. Pathological alterations of mtDNA fall into two main categories: primary mutations of mitochondrial DNA (point mutations and rearrangements) and mtDNA perturbation, due to mutations in nuclear genes whose products are involved in mtDNA maintenance or replication. This article will focus on the primary mitochondrial DNA mutations and mtDNA depletion syndromes related to neonatal-infant human pathology.
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Affiliation(s)
- A Spinazzola
- MRC, Mitochondrial Biology Unit, Wellcome Trust, MRC Building, Hills Road, Cambridge CB2 0XY, UK.
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