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Aguilar K, Jakubek P, Zorzano A, Wieckowski MR. Primary mitochondrial diseases: The intertwined pathophysiology of bioenergetic dysregulation, oxidative stress and neuroinflammation. Eur J Clin Invest 2024; 54:e14217. [PMID: 38644687 DOI: 10.1111/eci.14217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/23/2024]
Abstract
OBJECTIVES AND SCOPE Primary mitochondrial diseases (PMDs) are rare genetic disorders resulting from mutations in genes crucial for effective oxidative phosphorylation (OXPHOS) that can affect mitochondrial function. In this review, we examine the bioenergetic alterations and oxidative stress observed in cellular models of primary mitochondrial diseases (PMDs), shedding light on the intricate complexity between mitochondrial dysfunction and cellular pathology. We explore the diverse cellular models utilized to study PMDs, including patient-derived fibroblasts, induced pluripotent stem cells (iPSCs) and cybrids. Moreover, we also emphasize the connection between oxidative stress and neuroinflammation. INSIGHTS The central nervous system (CNS) is particularly vulnerable to mitochondrial dysfunction due to its dependence on aerobic metabolism and the correct functioning of OXPHOS. Similar to other neurodegenerative diseases affecting the CNS, individuals with PMDs exhibit several neuroinflammatory hallmarks alongside neurodegeneration, a pattern also extensively observed in mouse models of mitochondrial diseases. Based on histopathological analysis of postmortem human brain tissue and findings in mouse models of PMDs, we posit that neuroinflammation is not merely a consequence of neurodegeneration but a potential pathogenic mechanism for disease progression that deserves further investigation. This recognition may pave the way for novel therapeutic strategies for this group of devastating diseases that currently lack effective treatments. SUMMARY In summary, this review provides a comprehensive overview of bioenergetic alterations and redox imbalance in cellular models of PMDs while underscoring the significance of neuroinflammation as a potential driver in disease progression.
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Affiliation(s)
- Kevin Aguilar
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
| | - Patrycja Jakubek
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology PAS, Warsaw, Poland
| | - Antonio Zorzano
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona, Spain
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Barcelona, Spain
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology PAS, Warsaw, Poland
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de Muijnck C, van Schooneveld MJ, Plomp AS, Rodenburg RJ, van Genderen MM, Boon CJ. Leber's hereditary optic neuropathy like disease in MT-ATP6 variant m.8969G>A. Am J Ophthalmol Case Rep 2024; 34:102070. [PMID: 38756953 PMCID: PMC11096717 DOI: 10.1016/j.ajoc.2024.102070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 05/18/2024] Open
Abstract
Purpose To describe a case with Leber's hereditary optic neuropathy (LHON) like optic atrophy in the presence of MT-ATP6 gene variant m.8969G > A. Observations A 20-year-old patient with a history of mild developmental delay, mild cognitive impairment, and positional tremor presented with subacute painless visual loss over a few weeks. Mitochondrial genome sequencing revealed a variant in MT-ATP6, m.8969G > A (p.Ser148Asn). This variant was previously reported in association with mitochondrial myopathy, lactic acidosis, and sideroblastic anemia (MLASA) and with nephropathy, followed by brain atrophy, muscle weakness and arrhythmias, but not with optic atrophy. Conclusions and importance Rare variants in MT-ATP6 can also cause LHON like optic atrophy. It is important to perform further genetic analysis of mitochondrial DNA in genetically unsolved cases suspected of Leber's hereditary optic neuropathy to confirm the clinical diagnosis.
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Affiliation(s)
- Cansu de Muijnck
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht, the Netherlands
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Mary J. van Schooneveld
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands
| | - Astrid S. Plomp
- Department of Human Genetics, Amsterdam University Medical Centers, Amsterdam, the Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, the Netherlands
| | - Richard J. Rodenburg
- Radboud Center for Mitochondrial Medicine, Departments of Pediatrics and Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Maria M. van Genderen
- Department of Ophthalmology, University Medical Center Utrecht, Utrecht, the Netherlands
- Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, the Netherlands
| | - Camiel J.F. Boon
- Department of Ophthalmology, Amsterdam University Medical Centers, Amsterdam, the Netherlands
- Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
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Emperador S, Habbane M, López-Gallardo E, Del Rio A, Llobet L, Mateo J, Sanz-López AM, Fernández-García MJ, Sánchez-Tocino H, Benbunan-Ferreiro S, Calabuig-Goena M, Narvaez-Palazón C, Fernández-Vega B, González-Iglesias H, Urreizti R, Artuch R, Pacheu-Grau D, Bayona-Bafaluy P, Montoya J, Ruiz-Pesini E. Identification and characterization of a new pathologic mutation in a large Leber hereditary optic neuropathy pedigree. Orphanet J Rare Dis 2024; 19:148. [PMID: 38582886 PMCID: PMC10999093 DOI: 10.1186/s13023-024-03165-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 03/30/2024] [Indexed: 04/08/2024] Open
Abstract
BACKGROUND Most patients suffering from Leber hereditary optic neuropathy carry one of the three classic pathologic mutations, but not all individuals with these genetic alterations develop the disease. There are different risk factors that modify the penetrance of these mutations. The remaining patients carry one of a set of very rare genetic variants and, it appears that, some of the risk factors that modify the penetrance of the classical pathologic mutations may also affect the phenotype of these other rare mutations. RESULTS We describe a large family including 95 maternally related individuals, showing 30 patients with Leber hereditary optic neuropathy. The mutation responsible for the phenotype is a novel transition, m.3734A > G, in the mitochondrial gene encoding the ND1 subunit of respiratory complex I. Molecular-genetic, biochemical and cellular studies corroborate the pathogenicity of this genetic change. CONCLUSIONS With the study of this family, we confirm that, also for this very rare mutation, sex and age are important factors modifying penetrance. Moreover, this pedigree offers an excellent opportunity to search for other genetic or environmental factors that additionally contribute to modify penetrance.
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Affiliation(s)
- Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Mouna Habbane
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Laboratoire Biologie Et Santé, Faculté Des Sciences Ben M'Sick, Hassan II University of Casablanca, 20670, Casablanca, Morocco
| | - Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Alejandro Del Rio
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
| | - Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Certest Biotec, 50840-San Mateo de Gállego, Zaragoza, Spain
| | - Javier Mateo
- Servicio de Oftalmología, Hospital Clínico Universitario Lozano Blesa, 50009, Zaragoza, Spain
| | - Ana María Sanz-López
- Servicio de Oftalmología, Hospital Universitario de Toledo, 45004, Toledo, Spain
| | | | | | - Sol Benbunan-Ferreiro
- Servicio de Oftalmología. Hospital Universitario Río Hortega, 47012, Valladolid, Spain
| | - María Calabuig-Goena
- Servicio de Oftalmología. Hospital Universitario Río Hortega, 47012, Valladolid, Spain
| | | | | | - Hector González-Iglesias
- Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas (IPLA-CSIC), 33300-Villaviciosa, Asturias, Spain
| | - Roser Urreizti
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
- Departament de Bioquímica Clínica, Institut de Recerca Sant Joan de Déu, 08950, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
- Departament de Bioquímica Clínica, Institut de Recerca Sant Joan de Déu, 08950, Barcelona, Spain
| | - David Pacheu-Grau
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018, Zaragoza, Spain
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain.
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain.
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50009- and 50013, Zaragoza, Spain.
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009, Zaragoza, Spain.
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.
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Del Dotto V, Musiani F, Baracca A, Solaini G. Variants in Human ATP Synthase Mitochondrial Genes: Biochemical Dysfunctions, Associated Diseases, and Therapies. Int J Mol Sci 2024; 25:2239. [PMID: 38396915 PMCID: PMC10889682 DOI: 10.3390/ijms25042239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Mitochondrial ATP synthase (Complex V) catalyzes the last step of oxidative phosphorylation and provides most of the energy (ATP) required by human cells. The mitochondrial genes MT-ATP6 and MT-ATP8 encode two subunits of the multi-subunit Complex V. Since the discovery of the first MT-ATP6 variant in the year 1990 as the cause of Neuropathy, Ataxia, and Retinitis Pigmentosa (NARP) syndrome, a large and continuously increasing number of inborn variants in the MT-ATP6 and MT-ATP8 genes have been identified as pathogenic. Variants in these genes correlate with various clinical phenotypes, which include several neurodegenerative and multisystemic disorders. In the present review, we report the pathogenic variants in mitochondrial ATP synthase genes and highlight the molecular mechanisms underlying ATP synthase deficiency that promote biochemical dysfunctions. We discuss the possible structural changes induced by the most common variants found in patients by considering the recent cryo-electron microscopy structure of human ATP synthase. Finally, we provide the state-of-the-art of all therapeutic proposals reported in the literature, including drug interventions targeting mitochondrial dysfunctions, allotopic gene expression- and nuclease-based strategies, and discuss their potential translation into clinical trials.
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Affiliation(s)
- Valentina Del Dotto
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy; (V.D.D.); (G.S.)
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology (FABIT), University of Bologna, 40127 Bologna, Italy;
| | - Alessandra Baracca
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy; (V.D.D.); (G.S.)
| | - Giancarlo Solaini
- Laboratory of Biochemistry and Mitochondrial Pathophysiology, Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy; (V.D.D.); (G.S.)
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Sanchis-Juan A, Megy K, Stephens J, Armirola Ricaurte C, Dewhurst E, Low K, French CE, Grozeva D, Stirrups K, Erwood M, McTague A, Penkett CJ, Shamardina O, Tuna S, Daugherty LC, Gleadall N, Duarte ST, Hedrera-Fernández A, Vogt J, Ambegaonkar G, Chitre M, Josifova D, Kurian MA, Parker A, Rankin J, Reid E, Wakeling E, Wassmer E, Woods CG, Raymond FL, Carss KJ. Genome sequencing and comprehensive rare-variant analysis of 465 families with neurodevelopmental disorders. Am J Hum Genet 2023; 110:1343-1355. [PMID: 37541188 PMCID: PMC10432178 DOI: 10.1016/j.ajhg.2023.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/07/2023] [Accepted: 07/07/2023] [Indexed: 08/06/2023] Open
Abstract
Despite significant progress in unraveling the genetic causes of neurodevelopmental disorders (NDDs), a substantial proportion of individuals with NDDs remain without a genetic diagnosis after microarray and/or exome sequencing. Here, we aimed to assess the power of short-read genome sequencing (GS), complemented with long-read GS, to identify causal variants in participants with NDD from the National Institute for Health and Care Research (NIHR) BioResource project. Short-read GS was conducted on 692 individuals (489 affected and 203 unaffected relatives) from 465 families. Additionally, long-read GS was performed on five affected individuals who had structural variants (SVs) in technically challenging regions, had complex SVs, or required distal variant phasing. Causal variants were identified in 36% of affected individuals (177/489), and a further 23% (112/489) had a variant of uncertain significance after multiple rounds of re-analysis. Among all reported variants, 88% (333/380) were coding nuclear SNVs or insertions and deletions (indels), and the remainder were SVs, non-coding variants, and mitochondrial variants. Furthermore, long-read GS facilitated the resolution of challenging SVs and invalidated variants of difficult interpretation from short-read GS. This study demonstrates the value of short-read GS, complemented with long-read GS, in investigating the genetic causes of NDDs. GS provides a comprehensive and unbiased method of identifying all types of variants throughout the nuclear and mitochondrial genomes in individuals with NDD.
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Affiliation(s)
- Alba Sanchis-Juan
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Karyn Megy
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Jonathan Stephens
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Camila Armirola Ricaurte
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Eleanor Dewhurst
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Kayyi Low
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | | | - Detelina Grozeva
- Department of Medical Genetics, University of Cambridge, Cambridge, UK; Centre for Trials Research, Cardiff University, Cardiff, UK
| | - Kathleen Stirrups
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Marie Erwood
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Amy McTague
- Molecular Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, UK; Department of Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Christopher J Penkett
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Olga Shamardina
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Salih Tuna
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Louise C Daugherty
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Nicholas Gleadall
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Sofia T Duarte
- Hospital Dona Estefânia, Centro Hospitalar de Lisboa Central, Lisbon, Portugal
| | | | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women's and Children's Hospital, Birmingham, UK
| | - Gautam Ambegaonkar
- Child Development Centre, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Manali Chitre
- Clinical Medical School, University of Cambridge, Cambridge, UK
| | | | - Manju A Kurian
- Molecular Neurosciences, Zayed Centre for Research into Rare Disease in Children, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Alasdair Parker
- Clinical Medical School, University of Cambridge, Cambridge, UK; Child Development Centre, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Julia Rankin
- Department of Clinical Genetics, Royal Devon University Healthcare NHS Foundation Trust, Exeter, UK
| | - Evan Reid
- Cambridge Institute for Medical Research and Department of Medical Genetics, University of Cambridge, Cambridge, UK
| | - Emma Wakeling
- North West Thames Regional Genetics Service, Harrow, UK
| | - Evangeline Wassmer
- Neurology Department, Birmingham Women and Children's Hospital, Birmingham, UK
| | - C Geoffrey Woods
- Clinical Medical School, University of Cambridge, Cambridge, UK; Department of Medical Genetics, University of Cambridge, Cambridge, UK
| | - F Lucy Raymond
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Department of Medical Genetics, University of Cambridge, Cambridge, UK.
| | - Keren J Carss
- Department of Haematology, University of Cambridge, Cambridge, UK; NIHR BioResource, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK; Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK.
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Baranowska E, Niedzwiecka K, Panja C, Charles C, Dautant A, Poznanski J, di Rago JP, Tribouillard-Tanvier D, Kucharczyk R. Probing the pathogenicity of patient-derived variants of MT-ATP6 in yeast. Dis Model Mech 2023; 16:307138. [PMID: 37083953 PMCID: PMC10151828 DOI: 10.1242/dmm.049783] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 02/28/2023] [Indexed: 04/22/2023] Open
Abstract
The list of mitochondrial DNA (mtDNA) variants detected in individuals with neurodegenerative diseases is constantly growing. Evaluating their functional consequences and pathogenicity is not easy, especially when they are found in only a limited number of patients together with wild-type mtDNA (heteroplasmy). Owing to its amenability to mitochondrial genetic transformation and incapacity to stably maintain heteroplasmy, and the strong evolutionary conservation of the proteins encoded in mitochondria, Saccharomyces cerevisiae provides a convenient model to investigate the functional consequences of human mtDNA variants. We herein report the construction and energy-transducing properties of yeast models of eight MT-ATP6 gene variants identified in patients with various disorders: m.8843T>C, m.8950G>A, m.9016A>G, m.9025G>A, m.9029A>G, m.9058A>G, m.9139G>A and m.9160T>C. Significant defect in growth dependent on respiration and deficits in ATP production were observed in yeast models of m.8950G>A, m.9025G>A and m.9029A>G, providing evidence of pathogenicity for these variants. Yeast models of the five other variants showed very mild, if any, effect on mitochondrial function, suggesting that the variants do not have, at least alone, the potential to compromise human health.
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Affiliation(s)
- Emilia Baranowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106 Warsaw, Poland
| | - Katarzyna Niedzwiecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106 Warsaw, Poland
| | - Chiranjit Panja
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106 Warsaw, Poland
| | - Camille Charles
- University of Bordeaux, Centre National de la Recherche Scientifique, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France
| | - Alain Dautant
- University of Bordeaux, Centre National de la Recherche Scientifique, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France
| | - Jarosław Poznanski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106 Warsaw, Poland
| | - Jean-Paul di Rago
- University of Bordeaux, Centre National de la Recherche Scientifique, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France
| | - Déborah Tribouillard-Tanvier
- University of Bordeaux, Centre National de la Recherche Scientifique, Institut de Biochimie et Génétique Cellulaires, UMR 5095, F-33000 Bordeaux, France
| | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02106 Warsaw, Poland
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Finsterer J. Neuropathy, Ataxia, and Retinitis Pigmentosa Syndrome. J Clin Neuromuscul Dis 2023; 24:140-146. [PMID: 36809201 DOI: 10.1097/cnd.0000000000000422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVES To provide an overview about the phenotype, genotype, treatment, and outcome of neuropathy, ataxia, and retinitis pigmentosa (NARP) syndrome. METHODS Systematic review by application of appropriate search terms. RESULTS NARP syndrome is a syndromic mitochondrial disorder due to pathogenic variants in MT-ATP6. The canonical phenotypic features of NARP syndrome include proximal muscle weakness, axonal neuropathy, cerebellar ataxia, and retinitis pigmentosa. Noncanonical phenotypic features in NARP include epilepsy, cerebral or cerebellar atrophy, optic atrophy, cognitive impairment, dementia, sleep apnea syndrome, hearing impairment, renal insufficiency, and diabetes. So far, 10 pathogenic variants in MT-ATP6 have been associated with NARP, NARP-like syndrome, or NARP/maternally inherited Leigh overlap syndrome. Most pathogenic MT-ATP6 variants are missense, but a few truncating pathogenic variants have been reported. The most common variant responsible for NARP is the transversion m.8993T>G. Only symptomatic treatment for NARP syndrome is available. In most of the cases, patients die prematurely. Patients with late-onset NARP survive longer. CONCLUSIONS NARP is a rare, syndromic, monogenic mitochondrial disorder due to pathogenic variants in MT-ATP6. The nervous system and the eyes are most commonly affected. Although only symptomatic treatment is available, the outcome is usually fair.
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Liu Y, Zhao S, Chen X, Bian Y, Cao Y, Xu P, Zhang C, Zhang J, Zhao S, Zhao H. Variations in mitochondrial DNA coding and D-loop region are associated with early embryonic development defects in infertile women. Hum Genet 2023; 142:193-200. [PMID: 36352239 DOI: 10.1007/s00439-022-02505-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 10/31/2022] [Indexed: 11/11/2022]
Abstract
Mitochondrial DNA (mtDNA) plays a critical role in oocyte maturation, fertilization, and early embryonic development. Defects in mtDNA may determine the alteration of the mitochondrial function, affecting cellular oxidative phosphorylation and ATP supply, leading to impaired oocyte maturation, abnormal fertilization, and low embryonic developmental potential, ultimately leading to female infertility. This case-control study was established to investigate the correlation between mtDNA variations and early embryonic development defects. Peripheral blood was collected for next-generation sequencing from women who suffered the repeated failures of in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI) cycles due to early embryonic development defects as well as in-house healthy controls, and the sequencing results were statistically analyzed for all subjects. This study found that infertile women with early embryonic development defects carried more mtDNA variants, especially in the D-loop region, ATP6 gene, and CYTB gene. By univariate logistic regression analysis, 16 mtDNA variants were associated with an increased risk of early embryonic development defects (OR > 1, p < 0.05). Furthermore, we identified 16 potentially pathogenic mtDNA variants only in infertile cases. The data proved that mtDNA variations were associated with early embryonic development defects in infertile Chinese women.
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Affiliation(s)
- Yuqing Liu
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Shuai Zhao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Xiaolei Chen
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Yuehong Bian
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Yongzhi Cao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Peiwen Xu
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Changming Zhang
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Jiangtao Zhang
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Shigang Zhao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China.,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Han Zhao
- Center for Reproductive Medicine, Shandong University, 157 Jingliu Road, Jinan, 250021, Shandong, China. .,Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China. .,Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China. .,Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China. .,Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China. .,National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China.
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9
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A Mutation in Mouse MT-ATP6 Gene Induces Respiration Defects and Opposed Effects on the Cell Tumorigenic Phenotype. Int J Mol Sci 2023; 24:ijms24021300. [PMID: 36674816 PMCID: PMC9865613 DOI: 10.3390/ijms24021300] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 12/23/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023] Open
Abstract
As the last step of the OXPHOS system, mitochondrial ATP synthase (or complex V) is responsible for ATP production by using the generated proton gradient, but also has an impact on other important functions linked to this system. Mutations either in complex V structural subunits, especially in mtDNA-encoded ATP6 gene, or in its assembly factors, are the molecular cause of a wide variety of human diseases, most of them classified as neurodegenerative disorders. The role of ATP synthase alterations in cancer development or metastasis has also been postulated. In this work, we reported the generation and characterization of the first mt-Atp6 pathological mutation in mouse cells, an m.8414A>G transition that promotes an amino acid change from Asn to Ser at a highly conserved residue of the protein (p.N163S), located near the path followed by protons from the intermembrane space to the mitochondrial matrix. The phenotypic consequences of the p.N163S change reproduce the effects of MT-ATP6 mutations in human diseases, such as dependence on glycolysis, defective OXPHOS activity, ATP synthesis impairment, increased ROS generation or mitochondrial membrane potential alteration. These observations demonstrate that this mutant cell line could be of great interest for the generation of mouse models with the aim of studying human diseases caused by alterations in ATP synthase. On the other hand, mutant cells showed lower migration capacity, higher expression of MHC-I and slightly lower levels of HIF-1α, indicating a possible reduction of their tumorigenic potential. These results could suggest a protective role of ATP synthase inhibition against tumor transformation that could open the door to new therapeutic strategies in those cancer types relying on OXPHOS metabolism.
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10
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Baranowska E, Niedzwiecka K, Panja C, Charles C, Dautant A, di Rago JP, Tribouillard-Tanvier D, Kucharczyk R. Molecular basis of diseases induced by the mitochondrial DNA mutation m.9032 T > C. Hum Mol Genet 2022; 32:1313-1323. [PMID: 36434790 PMCID: PMC10077503 DOI: 10.1093/hmg/ddac292] [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: 09/05/2022] [Revised: 11/08/2022] [Accepted: 11/22/2022] [Indexed: 11/28/2022] Open
Abstract
The mitochondrial DNA mutation m.9032 T > C was previously identified in patients presenting with NARP (Neuropathy Ataxia Retinitis Pigmentosa). Their clinical features had a maternal transmission and patient's cells showed a reduced oxidative phosphorylation capacity, elevated reactive oxygen species (ROS) production and hyperpolarization of the mitochondrial inner membrane, providing evidence that m.9032 T > C is truly pathogenic. This mutation leads to replacement of a highly conserved leucine residue with proline at position 169 of ATP synthase subunit a (L169P). This protein and a ring of identical c-subunits (c-ring) move protons through the mitochondrial inner membrane coupled to ATP synthesis. We herein investigated the consequences of m.9032 T > C on ATP synthase in a strain of Saccharomyces cerevisiae with an equivalent mutation (L186P). The mutant enzyme assembled correctly but was mostly inactive as evidenced by a > 95% drop in the rate of mitochondrial ATP synthesis and absence of significant ATP-driven proton pumping across the mitochondrial membrane. Intragenic suppressors selected from L186P yeast restoring ATP synthase function to varying degrees (30-70%) were identified at the original mutation site (L186S) or in another position of the subunit a (H114Q, I118T). In light of atomic structures of yeast ATP synthase recently described, we conclude from these results that m.9032 T > C disrupts proton conduction between the external side of the membrane and the c-ring, and that H114Q and I118T enable protons to access the c-ring through a modified pathway.
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Affiliation(s)
- Emilia Baranowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Niedzwiecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Chiranjit Panja
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Camille Charles
- Univ. Bordeaux, CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Alain Dautant
- Univ. Bordeaux, CNRS, IBGC, UMR 5095, F-33000 Bordeaux, France
| | | | | | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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11
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Kuan SW, Chua KH, Tan EW, Tan LK, Loch A, Kee BP. Whole mitochondrial genome sequencing of Malaysian patients with cardiomyopathy. PeerJ 2022; 10:e13265. [PMID: 35441061 PMCID: PMC9013480 DOI: 10.7717/peerj.13265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/23/2022] [Indexed: 01/13/2023] Open
Abstract
Cardiomyopathy (CMP) constitutes a diverse group of myocardium diseases affecting the pumping ability of the heart. Genetic predisposition is among the major factors affecting the development of CMP. Globally, there are over 100 genes in autosomal and mitochondrial DNA (mtDNA) that have been reported to be associated with the pathogenesis of CMP. However, most of the genetic studies have been conducted in Western countries, with limited data being available for the Asian population. Therefore, this study aims to investigate the mutation spectrum in the mitochondrial genome of 145 CMP patients in Malaysia. Long-range PCR was employed to amplify the entire mtDNA, and whole mitochondrial genome sequencing was conducted on the MiSeq platform. Raw data was quality checked, mapped, and aligned to the revised Cambridge Reference Sequence (rCRS). Variants were named, annotated, and filtered. The sequencing revealed 1,077 variants, including 18 novel and 17 CMP and/or mitochondrial disease-associated variants after filtering. In-silico predictions suggested that three of the novel variants (m.8573G>C, m.11916T>A and m.11918T>G) in this study are potentially pathogenic. Two confirmed pathogenic variants (m.1555A>G and m.11778G>A) were also found in the CMP patients. The findings of this study shed light on the distribution of mitochondrial mutations in Malaysian CMP patients. Further functional studies are required to elucidate the role of these variants in the development of CMP.
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Affiliation(s)
- Sheh Wen Kuan
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kek Heng Chua
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - E-Wei Tan
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Lay Koon Tan
- National Heart Institute, Kuala Lumpur, Malaysia
| | - Alexander Loch
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Boon Pin Kee
- Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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12
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Na J, Lee Y. Genotype-phenotype analysis of MT-ATP6-associated Leigh syndrome. Acta Neurol Scand 2022; 145:414-422. [PMID: 34877647 DOI: 10.1111/ane.13566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/25/2021] [Accepted: 11/27/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Mitochondrial DNA (mtDNA)-associated Leigh syndrome (LS) is characterized by maternal inheritance, and the heteroplasmic mutant load of mtDNA pathogenic variants is known to affect clinical phenotypes. Among mtDNA pathogenic variants, variants of the MT-ATP6 gene account for most of reported cases. In this report, we aimed to describe the clinical and genetic findings of MT-ATP6-associated LS patients diagnosed at a single tertiary institution in Korea. METHODS Thirteen patients with genetically confirmed MT-ATP6-associated LS were selected. We reviewed each patient's clinical findings, including general characteristics, biochemical parameters, brain MR images, muscle biopsy results, and heteroplasmic mutant load over a long-term follow-up period. RESULTS MT-ATP6-associated LS was of predominantly early onset (age <2 years), although we identified 2 late-onset (>60 months) LS patients. The heteroplasmic mutant load estimated by next-generation sequencing was 96%-100% in all nucleotide change groups. Compared with other forms of MT-ATP6-associated LS, the m.8993T>G point mutation elicited a significantly higher rate of symptom onset before 2 years of age. Brain MRI showed bilateral basal ganglia involvement in all patients, followed by cerebral atrophy, brainstem and thalamus involvement, and cerebellar atrophy. After follow-up (median 7.2 years, range 1.4 to 11.5 years), LS with m.8993T>G point mutations had a slightly more severe clinical progression compared with other forms of MT-ATP6-associated LS. CONCLUSIONS MT-ATP6-associated LS patients presented with a broad spectrum of clinical diagnoses and had a very high heteroplasmic mutant load. This study provides valuable data on MT-ATP6-associated LS that will inform subsequent studies on LS.
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Affiliation(s)
- Ji‐Hoon Na
- Department of Pediatrics Yonsei University College of Medicine Seoul Korea
| | - Young‐Mock Lee
- Department of Pediatrics Yonsei University College of Medicine Seoul Korea
- Epilepsy Research Institute Yonsei University College of Medicine Seoul Korea
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13
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Garone C, Pietra A, Nesci S. From the Structural and (Dys)Function of ATP Synthase to Deficiency in Age-Related Diseases. Life (Basel) 2022; 12:life12030401. [PMID: 35330152 PMCID: PMC8949411 DOI: 10.3390/life12030401] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 02/25/2022] [Accepted: 03/08/2022] [Indexed: 12/21/2022] Open
Abstract
The ATP synthase is a mitochondrial inner membrane complex whose function is essential for cell bioenergy, being responsible for the conversion of ADP into ATP and playing a role in mitochondrial cristae morphology organization. The enzyme is composed of 18 protein subunits, 16 nuclear DNA (nDNA) encoded and two mitochondrial DNA (mtDNA) encoded, organized in two domains, FO and F1. Pathogenetic variants in genes encoding structural subunits or assembly factors are responsible for fatal human diseases. Emerging evidence also underlines the role of ATP-synthase in neurodegenerative diseases as Parkinson’s, Alzheimer’s, and motor neuron diseases such as Amyotrophic Lateral Sclerosis. Post-translational modification, epigenetic modulation of ATP gene expression and protein level, and the mechanism of mitochondrial transition pore have been deemed responsible for neuronal cell death in vivo and in vitro models for neurodegenerative diseases. In this review, we will explore ATP synthase assembly and function in physiological and pathological conditions by referring to the recent cryo-EM studies and by exploring human disease models.
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Affiliation(s)
- Caterina Garone
- Department of Medical and Surgical Sciences, Alma Mater Studiorum University of Bologna, 40137 Bologna, Italy;
- Center for Applied Biomedical Research, Alma Mater Studiorum University of Bologna, 40137 Bologna, Italy
- UOC Neuropsichiatria dell’età Pediatrica, IRCCS Istituto delle Scienze Neurologiche di Bologna, 40137 Bologna, Italy
- Correspondence: (C.G.); (S.N.); Tel.: +39-051-2094763 (C.G.); Tel.: +39-051-209-7004 (S.N.)
| | - Andrea Pietra
- Department of Medical and Surgical Sciences, Alma Mater Studiorum University of Bologna, 40137 Bologna, Italy;
- UO Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, 40137 Bologna, Italy
| | - Salvatore Nesci
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy
- Correspondence: (C.G.); (S.N.); Tel.: +39-051-2094763 (C.G.); Tel.: +39-051-209-7004 (S.N.)
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14
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Juaristi L, Irigoyen C, Quiroga J. NEUROPATHY, ATAXIA, AND RETINITIS PIGMENTOSA SYNDROME: A MULTIDISCIPLINARY DIAGNOSIS. Retin Cases Brief Rep 2021; 15:486-489. [PMID: 30346353 PMCID: PMC8219086 DOI: 10.1097/icb.0000000000000835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To report a case of neuropathy, ataxia, and retinitis pigmentosa syndrome, a rare and undiagnosed disease in ophthalmology due to the need for multidisciplinary evaluation. METHODS Multimodal testing was performed, including neurologic, ophthalmologic, and genetic assessments. The neurologic tests comprised electromyogram and muscle biopsy; the ophthalmologic examination consisted of slit-lamp and fundus examinations, optical coherence tomography, visual field testing, and electrophysiology tests such as a full-field electroretinogram and multifocal electroretinogram; and genetic tests were performed for spinocerebellar ataxia. In addition, the patient underwent magnetic resonance imaging, an electrocardiogram, cerebrospinal fluid analysis with lactate levels, and a blood workup including antineuronal, antithyroid peroxidase, antinuclear, antimitochondrial, and antitransglutaminase antibodies and fat-soluble vitamins (A, D, E, K). RESULTS The ocular fundus examination showed bone spicules with retinal pigment epithelium alteration, optic nerve pallor, and arterial attenuation. Optical coherence tomography demonstrated macular atrophy. Visual field testing revealed concentric reduction. Electrophysiology examinations showed involvement of rods and cones in both eyes. The muscle biopsy was compatible with mitochondrial disease, and electromyogram demonstrated sensory axonal damage. However, genetic tests for spinocerebellar ataxia were negative. Magnetic resonance imaging showed cerebellar atrophy, whereas the electrocardiogram did not detect any abnormalities. Cerebrospinal fluid lactate levels were above normal but antibody levels in blood were normal. CONCLUSION This is the first report of macular atrophy demonstrated by optical coherence tomography in a patient with neuropathy, ataxia, and retinitis pigmentosa syndrome. For the diagnosis, a multidisciplinary team including a neurologist, a geneticist, and an ophthalmologist was essential. Patients with suspected mitochondrial disease could greatly benefit from an ophthalmology examination like that conducted in this case because it was the key factor that led to the suspicion of syndromic disease, and ultimately the diagnosis.
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Affiliation(s)
- Leire Juaristi
- Department of Ophthalmology, Donostia University Hospital, Donostia - San-Sebastian, Spain
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15
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Nolte D, Kang JS, Hofmann A, Schwaab E, Krämer HH, Müller U. Mutations in MT-ATP6 are a frequent cause of adult-onset spinocerebellar ataxia. J Neurol 2021; 268:4866-4873. [PMID: 34037856 PMCID: PMC8563540 DOI: 10.1007/s00415-021-10607-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/06/2021] [Accepted: 05/08/2021] [Indexed: 01/30/2023]
Abstract
Adult-onset ataxias are a genetically and clinically heterogeneous group of movement disorders. In addition to nuclear gene mutations, sequence changes have also been described in the mitochondrial genome. Here, we present findings of mutation analysis of the mitochondrial gene MT-ATP6. We analyzed 94 patients with adult-onset spinocerebellar ataxia (SCA), including 34 sporadic cases. In all patients, common sequence changes found in SCAs such as repeat expansions and point mutations had been excluded previously. We found pathogenic MT-ATP variants in five of these patients (5.32%), two of whom were sporadic. Four of the five mutations have not previously been described in ataxias. All but one of these mutations affect transmembrane helices of subunit-α of ATP synthase. Two mutations (p.G16S, and p.P18S) disrupt transmembrane helix 1 (TMH1), one mutation (p.G167D) affects TMH5, and another one (p.L217P) TMH6. The fifth mutation (p.T96A) describes an amino acid change in close proximity to transmembrane helix 3 (TMH3). The level of heteroplasmy was either complete or very high ranging from 87 to 99%. The high prevalence of pathogenic MT-ATP6 variants suggests that analysis of this gene should be included in the routine workup of both hereditary and sporadic ataxias.
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Affiliation(s)
- Dagmar Nolte
- Institut für Humangenetik , Justus-Liebig-Universität Giessen, Schlangenzahl 14, Giessen, 35392, Germany.
| | - Jun-Suk Kang
- Klinikum der Johann Wolfgang Goethe-Universität, Klinik für Neurologie, Frankfurt, Germany.,Neuropraxis, Frankfurt, Germany
| | - Amrei Hofmann
- Institut für Humangenetik , Justus-Liebig-Universität Giessen, Schlangenzahl 14, Giessen, 35392, Germany.,Klinikum Worms, Klinik für Pädiatrie, Worms, Germany
| | - Eva Schwaab
- Praxis für Humangenetik , Wiesbaden, Germany
| | - Heidrun H Krämer
- Klinik für Neurologie , Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Ulrich Müller
- Institut für Humangenetik , Justus-Liebig-Universität Giessen, Schlangenzahl 14, Giessen, 35392, Germany
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16
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Knight KM, Shelkowitz E, Larson AA, Mirsky DM, Wang Y, Chen T, Wong LJ, Friederich MW, Van Hove JLK. The mitochondrial DNA variant m.9032T > C in MT-ATP6 encoding p.(Leu169Pro) causes a complex mitochondrial neurological syndrome. Mitochondrion 2020; 55:8-13. [PMID: 32931937 DOI: 10.1016/j.mito.2020.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 07/09/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Diagnosing complex V deficiencies caused by new variants in mitochondrial DNA is challenging due to the rarity, phenotypic diversity, and limited functional assessments. We describe a child with the m.9032T > C variant in MT-ATP6 encoding p.(Leu169Pro), with primary presentation of microcephaly, ataxia, hearing loss, and lactic acidosis. Functional studies reveal abnormal fragment F1 of complex V on blue native gel electrophoresis. Respirometry showed excessively tight coupling through complex V depressing oxygen consumption upon ADP stimulation and an excessive increase following uncoupling, in the presence of upregulation of mitochondrial biogenesis. These data add evidence about pathogenicity and functional impact of this variant.
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Affiliation(s)
- Kaz M Knight
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - Emily Shelkowitz
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - Austin A Larson
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA
| | - David M Mirsky
- Department of Radiology, University of Colorado, and Children's Hospital Colorado, Aurora, CO, USA
| | - Yue Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Ting Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Endocrinology, Genetics and Metabolism, Children's Hospital of Soochow University, Suzhou, China
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Marisa W Friederich
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA; Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, 13121 East 16th Avenue, Aurora, CO, USA
| | - Johan L K Van Hove
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA; Department of Pathology and Laboratory Medicine, Children's Hospital Colorado, 13121 East 16th Avenue, Aurora, CO, USA.
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17
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Habbane M, Llobet L, Bayona-Bafaluy MP, Bárcena JE, Ceberio L, Gómez-Díaz C, Gort L, Artuch R, Montoya J, Ruiz-Pesini E. Leigh Syndrome in a Pedigree Harboring the m.1555A>G Mutation in the Mitochondrial 12S rRNA. Genes (Basel) 2020; 11:genes11091007. [PMID: 32867169 PMCID: PMC7565518 DOI: 10.3390/genes11091007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/28/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Leigh syndrome (LS) is a serious genetic disease that can be caused by mutations in dozens of different genes. Methods: Clinical study of a deafness pedigree in which some members developed LS. Cellular, biochemical and molecular genetic analyses of patients’ tissues and cybrid cell lines were performed. Results: mitochondrial DNA (mtDNA) m.1555A>G/MT-RNR1 and m.9541T>C/MT-CO3 mutations were found. The first one is a well-known pathologic mutation. However, the second one does not appear to contribute to the high hearing loss penetrance and LS phenotype observed in this family. Conclusion: The m.1555A>G pathological mutation, accompanied with an unknown nuclear DNA (nDNA) factor, could be the cause of the phenotypic manifestations in this pedigree.
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Affiliation(s)
- Mouna Habbane
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.H.); (L.L.); (M.P.B.-B.); (J.M.)
- Laboratoire Biologie et Santé, Faculté des Sciences Ben M’Sik, Université Hassan II, 20670 Casablanca, Morocco
| | - Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.H.); (L.L.); (M.P.B.-B.); (J.M.)
| | - M. Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.H.); (L.L.); (M.P.B.-B.); (J.M.)
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009 Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (L.G.); (R.A.)
| | - José E. Bárcena
- Servicio de Neurología, Hospital Universitario Cruces, 48903 Baracaldo, Vizcaya, Spain;
| | - Leticia Ceberio
- Servicio de Medicina Interna, Hospital Universitario Cruces, 48903 Baracaldo, Vizcaya, Spain;
| | - Covadonga Gómez-Díaz
- Servicio de Otorrinolaringología, Hospital Universitario Miguel Servet, 50009 Zaragoza, Spain;
| | - Laura Gort
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (L.G.); (R.A.)
- Errors Congènits del Metabolisme, Servicio de Bioquímica i Genètica Molecular, CDB, Hospital Clínic, IDIBAPS, 08036 Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (L.G.); (R.A.)
- Servicio de Bioquímica Clínica, Institut de Recerca Sant Joan de Déu, 08950 Barcelona, Spain
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.H.); (L.L.); (M.P.B.-B.); (J.M.)
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009 Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (L.G.); (R.A.)
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.H.); (L.L.); (M.P.B.-B.); (J.M.)
- Instituto de Investigación Sanitaria (IIS) de Aragón, 50009 Zaragoza, Spain
- Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (L.G.); (R.A.)
- Fundación Araid, 50018 Zaragoza, Spain
- Correspondence: ; Tel.: +34-976761646
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18
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Wong LJC, Chen T, Schmitt ES, Wang J, Tang S, Landsverk M, Li F, Zhang S, Wang Y, Zhang VW, Craigen WJ. Clinical and laboratory interpretation of mitochondrial mRNA variants. Hum Mutat 2020; 41:1783-1796. [PMID: 32652755 DOI: 10.1002/humu.24082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/29/2020] [Accepted: 07/09/2020] [Indexed: 12/26/2022]
Abstract
Interpretation of mitochondrial protein-encoding (mt-mRNA) variants has been challenging due to mitochondrial characteristics that have not been addressed by American College of Medical Genetics and Genomics guidelines. We developed criteria for the interpretation of mt-mRNA variants via literature review of reported variants, tested and refined these criteria by using our new cases, followed by interpreting 421 novel variants in our clinical database using these verified criteria. A total of 32 of 56 previously reported pathogenic (P) variants had convincing evidence for pathogenicity. These variants are either null variants, well-known disease-causing variants, or have robust functional data or strong phenotypic correlation with heteroplasmy levels. Based on our criteria, 65.7% (730/1,111) of variants of unknown significance (VUS) were reclassified as benign (B) or likely benign (LB), and one variant was scored as likely pathogenic (LP). Furthermore, using our criteria we classified 2, 12, and 23 as P, LP, and LB, respectively, among 421 novel variants. The remaining stayed as VUS (91.2%). Appropriate interpretation of mt-mRNA variants is the basis for clinical diagnosis and genetic counseling. Mutation type, heteroplasmy levels in different tissues of the probands and matrilineal relatives, in silico predictions, population data, as well as functional studies are key points for pathogenicity assessments.
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Affiliation(s)
- Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
| | - Ting Chen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Eric S Schmitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
| | - Jing Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Sha Tang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Megan Landsverk
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Fangyuan Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Shulin Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Yue Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
| | - Victor W Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Baylor Genetics Laboratory, Houston, Texas
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19
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López-Gallardo E, Cammarata-Scalisi F, Emperador S, Hernández-Ainsa C, Habbane M, Vela-Sebastián A, Bayona-Bafaluy MP, Montoya J, Ruiz-Pesini E. Mitochondrial DNA pathogenic mutations in multiple symmetric lipomatosis. Clin Genet 2020; 97:731-735. [PMID: 31912494 DOI: 10.1111/cge.13701] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/30/2019] [Accepted: 12/30/2019] [Indexed: 12/25/2022]
Abstract
The frequency of dermatological manifestations in diseases due to mitochondrial DNA mutations is not well known, although multiple symmetric lipomatosis has been repeatedly associated to mitochondrial DNA mutations. Here, we present a patient suffering from multiple symmetric lipomatosis and other skin signs. We found a new mitochondrial DNA mutation, m.8357T>C, in the tRNALys -coding gene and, using a cybrid approach, confirmed its pathogenicity. A meta-analysis of the dermatological signs of the patient shows that they are not common in patients with confirmed mitochondrial DNA mutations and suggests that, in these cases, lipomatosis is not related to the oxidative phosphorylation dysfunction, but to an alteration of an additional function associated to particular mitochondrial tRNAs.
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Affiliation(s)
- Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria (IIS) de Aragón, Zaragoza, Spain.,Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Francisco Cammarata-Scalisi
- Unidad de Genética Médica, Departamento de Puericultura y Pediatría, Universidad de Los Andes, Mérida, Venezuela
| | - Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria (IIS) de Aragón, Zaragoza, Spain.,Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Carmen Hernández-Ainsa
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria (IIS) de Aragón, Zaragoza, Spain
| | - Mouna Habbane
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Faculté des Sciences Ben M'Sik, Université Hassan II, Casablanca, Morocco
| | - Ana Vela-Sebastián
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - María Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria (IIS) de Aragón, Zaragoza, Spain.,Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria (IIS) de Aragón, Zaragoza, Spain.,Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria (IIS) de Aragón, Zaragoza, Spain.,Centro de Investigaciones Biomédicas en Red de Enfermedades Raras (CIBERER), Madrid, Spain.,Fundación ARAID, Zaragoza, Spain
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20
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Shinoda S, Kitagawa S, Nakagawa S, Wei FY, Tomizawa K, Araki K, Araki M, Suzuki T, Suzuki T. Mammalian NSUN2 introduces 5-methylcytidines into mitochondrial tRNAs. Nucleic Acids Res 2019; 47:8734-8745. [PMID: 31287866 PMCID: PMC6895283 DOI: 10.1093/nar/gkz575] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/15/2019] [Accepted: 06/20/2019] [Indexed: 12/11/2022] Open
Abstract
Post-transcriptional modifications in mitochondrial tRNAs (mt-tRNAs) play critical roles in mitochondrial protein synthesis, which produces respiratory chain complexes. In this study, we took advantage of mass spectrometric analysis to map 5-methylcytidine (m5C) at positions 48–50 in eight mouse and six human mt-tRNAs. We also confirmed the absence of m5C in mt-tRNAs isolated from Nsun2 knockout (KO) mice, as well as from NSUN2 KO human culture cells. In addition, we successfully reconstituted m5C at positions 48–50 of mt-tRNA in vitro with NSUN2 protein in the presence of S-adenosylmethionine. Although NSUN2 is predominantly localized to the nucleus and introduces m5C into cytoplasmic tRNAs and mRNAs, structured illumination microscopy clearly revealed NSUN2 foci inside mitochondria. These observations provide novel insights into the role of NSUN2 in the physiology and pathology of mitochondrial functions.
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Affiliation(s)
- Saori Shinoda
- Department of Chemistry and Biotechnology, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Sho Kitagawa
- Department of Chemistry and Biotechnology, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Shinichi Nakagawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido 060-0812, Japan
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012 Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan
| | - Masatake Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan
| | - Takeo Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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21
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Ganetzky RD, Stendel C, McCormick EM, Zolkipli-Cunningham Z, Goldstein AC, Klopstock T, Falk MJ. MT-ATP6 mitochondrial disease variants: Phenotypic and biochemical features analysis in 218 published cases and cohort of 14 new cases. Hum Mutat 2019; 40:499-515. [PMID: 30763462 DOI: 10.1002/humu.23723] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/29/2019] [Accepted: 02/11/2019] [Indexed: 01/30/2023]
Abstract
Mitochondrial complex V (CV) generates cellular energy as adenosine triphosphate (ATP). Mitochondrial disease caused by the m.8993T>G pathogenic variant in the CV subunit gene MT-ATP6 was among the first described human mitochondrial DNA diseases. Due to a lack of clinically available functional assays, validating the definitive pathogenicity of additional MT-ATP6 variants remains challenging. We reviewed all reportedMT-ATP6 disease cases ( n = 218) to date, to assess for MT-ATP6 variants, heteroplasmy levels, and inheritance correlation with clinical presentation and biochemical findings. We further describe the clinical and biochemical features of a new cohort of 14 kindreds with MT-ATP6 variants of uncertain significance. Despite extensive overlap in the heteroplasmy levels of MT-ATP6 variant carriers with and without a wide range of clinical symptoms, previously reported symptomatic subjects had significantly higher heteroplasmy load (p = 2.2 x 10-16 ). Pathogenic MT-ATP6 variants resulted in diverse biochemical features. The most common findings were reduced ATP synthesis rate, preserved ATP hydrolysis capacity, and abnormally increased mitochondrial membrane potential. However, no single biochemical feature was universally observed. Extensive heterogeneity exists among both clinical and biochemical features of distinct MT-ATP6 variants. Improved mechanistic understanding and development of consistent biochemical diagnostic analyses are needed to permit accurate pathogenicity assessment of variants of uncertain significance in MT-ATP6.
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Affiliation(s)
- Rebecca D Ganetzky
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Claudia Stendel
- Department of Psychiatry, Ludwig Maximilians University of Munich, Munich, Germany
| | - Elizabeth M McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Zarazuela Zolkipli-Cunningham
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Amy C Goldstein
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Thomas Klopstock
- Department of Neurology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Marni J Falk
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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22
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Von der isolierten Optikusatrophie zur Multisystemerkrankung. Monatsschr Kinderheilkd 2018. [DOI: 10.1007/s00112-017-0318-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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23
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Byrnes J, Ganetzky R, Lightfoot R, Tzeng M, Nakamaru-Ogiso E, Seiler C, Falk MJ. Pharmacologic modeling of primary mitochondrial respiratory chain dysfunction in zebrafish. Neurochem Int 2018; 117:23-34. [PMID: 28732770 PMCID: PMC5773416 DOI: 10.1016/j.neuint.2017.07.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 07/11/2017] [Accepted: 07/16/2017] [Indexed: 02/07/2023]
Abstract
Mitochondrial respiratory chain (RC) disease is a heterogeneous and highly morbid group of energy deficiency disorders for which no proven effective therapies exist. Robust vertebrate animal models of primary RC dysfunction are needed to explore the effects of variation in RC disease subtypes, tissue-specific manifestations, and major pathogenic factors contributing to each disorder, as well as their pre-clinical response to therapeutic candidates. We have developed a series of zebrafish (Danio rerio) models that inhibit, to variable degrees, distinct aspects of RC function, and enable quantification of animal development, survival, behaviors, and organ-level treatment effects as well as effects on mitochondrial biochemistry and physiology. Here, we characterize four pharmacologic inhibitor models of mitochondrial RC dysfunction in early larval zebrafish, including rotenone (complex I inhibitor), azide (complex IV inhibitor), oligomycin (complex V inhibitor), and chloramphenicol (mitochondrial translation inhibitor that leads to multiple RC complex dysfunction). A range of concentrations and exposure times of each RC inhibitor were systematically evaluated on early larval development, animal survival, integrated behaviors (touch and startle responses), organ physiology (brain death, neurologic tone, heart rate), and fluorescence-based analyses of mitochondrial physiology in zebrafish skeletal muscle. Pharmacologic RC inhibitor effects were validated by spectrophotometric analysis of Complex I, II and IV enzyme activities, or relative quantitation of ATP levels in larvae. Outcomes were prioritized that utilize in vivo animal imaging and quantitative behavioral assessments, as may optimally inform the translational potential of pre-clinical drug screens for future clinical study in human mitochondrial disease subjects. The RC complex inhibitors each delayed early embryo development, with short-term exposures of these three agents or chloramphenicol from 5 to 7 days post fertilization also causing reduced larval survival and organ-specific defects ranging from brain death, behavioral and neurologic alterations, reduced mitochondrial membrane potential in skeletal muscle (rotenone), and/or cardiac edema with visible blood pooling (oligomycin). Remarkably, we demonstrate that treating animals with probucol, a nutrient-sensing signaling network modulating drug that has been shown to yield therapeutic effects in a range of other RC disease cellular and animal models, both prevented acute rotenone-induced brain death in zebrafish larvae, and significantly rescued early embryo developmental delay from either rotenone or oligomycin exposure. Overall, these zebrafish pharmacologic RC function inhibition models offer a unique opportunity to gain novel insights into diverse developmental, survival, organ-level, and behavioral defects of varying severity, as well as their individual response to candidate therapies, in a highly tractable and cost-effective vertebrate animal model system.
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Affiliation(s)
- James Byrnes
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Rebecca Ganetzky
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Richard Lightfoot
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Michael Tzeng
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Eiko Nakamaru-Ogiso
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States
| | - Christoph Seiler
- Aquatics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, United States
| | - Marni J Falk
- Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, United States; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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24
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Masserrat A, Sharifpanah F, Akbari L, Tonekaboni SH, Karimzadeh P, Asharafi MR, Mazouei S, Sauer H, Houshmand M. Mitochondrial G8292A and C8794T mutations in patients with Niemann-Pick disease type C. Biomed Rep 2018; 9:65-73. [PMID: 29930807 DOI: 10.3892/br.2018.1095] [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: 11/02/2017] [Accepted: 04/27/2018] [Indexed: 11/06/2022] Open
Abstract
Niemann-Pick disease type C (NP-C) is a neurovisceral lipid storage disorder. At the cellular level, the disorder is characterized by accumulation of unesterified cholesterol and glycolipids in the lysosomal/late endosomal system. NP-C is transmitted in an autosomal recessive manner and is caused by mutations in either the NPC1 (95% of families) or NPC2 gene. The estimated disease incidence is 1 in 120,000 live births, but this likely represents an underestimate, as the disease may be under-diagnosed due to its highly heterogeneous presentation. Variants of adenosine triphosphatase (ATPase) subunit 6 and ATPase subunit 8 (ATPase6/8) in mitochondrial DNA (mtDNA) have been reported in different types of genetic diseases including NP-C. In the present study, the blood samples of 22 Iranian patients with NP-C and 150 healthy subjects as a control group were analyzed. The DNA of the blood samples was extracted by the salting out method and analyzed for ATPase6/8 mutations using polymerase chain reaction sequencing. Sequence variations in mitochondrial genome samples were determined via the Mitomap database. Analysis of sequencing data confirmed the existence of 11 different single nucleotide polymorphisms (SNPs) in patients with NP-C1. One of the most prevalent polymorphisms was the A8860G variant, which was observed in both affected and non-affected groups and determined to have no significant association with NP-C incidence. Amongst the 11 polymorphisms, only one was identified in the ATPase8 gene, while 9 including A8860G were observed in the ATPase6 gene. Furthermore, two SNPs, G8292A and C8792A, located in the non-coding region of mtDNA and the ATPase6 gene, respectively, exhibited significantly higher prevalence rates in NP-C1 patients compared with the control group (P<0.01). The present study suggests that there may be an association between mitochondrial ATPase6/8 mutations and the incidence of NP-C disease. In addition, the mitochondrial SNPs identified maybe pathogenic mutations involved in the development and prevalence of NP-C. Furthermore, these results suggest a higher occurrence of mutations in ATPase6 than in ATPase8 in NP-C patients.
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Affiliation(s)
- Abbas Masserrat
- Department of Biology, Faculty of Science, Islamic Azad University, Damghan 3671639998, Iran
| | - Fatemeh Sharifpanah
- Department of Physiology, Faculty of Medicine, Justus Liebig University, D-35392 Giessen, Germany
| | - Leila Akbari
- Houshmand Genetic Diagnostics Laboratory, Taban Clinic, Tehran 1997844151, Iran.,School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Seyed Hasan Tonekaboni
- Department of Neurology, Faculty of Medicine, Shahid Beheshti University, Tehran 19839-63113, Iran
| | - Parvaneh Karimzadeh
- Department of Neurology, Faculty of Medicine, Shahid Beheshti University, Tehran 19839-63113, Iran
| | - Mahmood Reza Asharafi
- Department of Neurology, Faculty of Medicine, Tehran University, Tehran 1417613151, Iran
| | - Safoura Mazouei
- Department of Cardiology, Clinic of Internal Medicine I, Friedrich Schiller University, D-07747 Jena, Germany
| | - Heinrich Sauer
- Department of Physiology, Faculty of Medicine, Justus Liebig University, D-35392 Giessen, Germany
| | - Massoud Houshmand
- Department of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran 14965/161, Iran
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25
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Uittenbogaard M, Brantner CA, Fang Z, Wong LJC, Gropman A, Chiaramello A. Novel insights into the functional metabolic impact of an apparent de novo m.8993T>G variant in the MT-ATP6 gene associated with maternally inherited form of Leigh Syndrome. Mol Genet Metab 2018; 124:71-81. [PMID: 29602698 PMCID: PMC6016550 DOI: 10.1016/j.ymgme.2018.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/22/2018] [Accepted: 03/22/2018] [Indexed: 01/02/2023]
Abstract
In this study, we report a novel perpective of metabolic consequences for the m.8993T>G variant using fibroblasts from a proband with clinical symptoms compatible with Maternally Inherited Leigh Syndrome (MILS). Definitive diagnosis was corroborated by mitochondrial DNA testing for the pathogenic variant m.8993T>G in MT-ATP6 subunit by Sanger sequencing. The long-range PCR followed by massively parallel sequencing method detected the near homoplasmic m.8993T>G variant at 83% in the proband's fibroblasts and at 0.4% in the mother's fibroblasts. Our results are compatible with very low levels of germline heteroplasmy or an apparent de novo mutation. Our mitochondrial morphometric analysis reveals severe defects in mitochondrial cristae structure in the proband's fibroblasts. Our live-cell mitochondrial respiratory analyses show impaired oxidative phosphorylation with decreased spare respiratory capacity in response to energy stress in the proband's fibroblasts. We detected a diminished glycolysis with a lessened glycolytic capacity and reserve, revealing a stunted ability to switch to glycolysis upon full inhibition of OXPHOS activities. This dysregulated energy reprogramming results in a defective interplay between OXPHOS and glycolysis during an energy crisis. Our study sheds light on the potential pathophysiologic mechanism leading to chronic energy crisis in this MILS patient harboring the m.8993T>G variant.
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Affiliation(s)
- Martine Uittenbogaard
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA
| | - Christine A Brantner
- GW Nanofabrication and Imaging Center, Office of the Vice President for Research, George Washington University, Washington, DC 20052, USA
| | - ZiShui Fang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Andrea Gropman
- Children's National Medical Center, Division of Neurogenetics and Developmental Pediatrics, Washington, DC 20010, USA
| | - Anne Chiaramello
- Department of Anatomy and Regenerative Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20037, USA.
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26
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Dautant A, Meier T, Hahn A, Tribouillard-Tanvier D, di Rago JP, Kucharczyk R. ATP Synthase Diseases of Mitochondrial Genetic Origin. Front Physiol 2018; 9:329. [PMID: 29670542 PMCID: PMC5893901 DOI: 10.3389/fphys.2018.00329] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/15/2018] [Indexed: 01/30/2023] Open
Abstract
Devastating human neuromuscular disorders have been associated to defects in the ATP synthase. This enzyme is found in the inner mitochondrial membrane and catalyzes the last step in oxidative phosphorylation, which provides aerobic eukaryotes with ATP. With the advent of structures of complete ATP synthases, and the availability of genetically approachable systems such as the yeast Saccharomyces cerevisiae, we can begin to understand these molecular machines and their associated defects at the molecular level. In this review, we describe what is known about the clinical syndromes induced by 58 different mutations found in the mitochondrial genes encoding membrane subunits 8 and a of ATP synthase, and evaluate their functional consequences with respect to recently described cryo-EM structures.
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Affiliation(s)
- Alain Dautant
- Institut de Biochimie et Génétique Cellulaires, Centre National de la Recherche Scientifique UMR 5095, Université de Bordeaux, Bordeaux, France
| | - Thomas Meier
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Alexander Hahn
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Frankfurt, Germany
| | - Déborah Tribouillard-Tanvier
- Institut de Biochimie et Génétique Cellulaires, Centre National de la Recherche Scientifique UMR 5095, Université de Bordeaux, Bordeaux, France
| | - Jean-Paul di Rago
- Institut de Biochimie et Génétique Cellulaires, Centre National de la Recherche Scientifique UMR 5095, Université de Bordeaux, Bordeaux, France
| | - Roza Kucharczyk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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27
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Emperador S, Vidal M, Hernández-Ainsa C, Ruiz-Ruiz C, Woods D, Morales-Becerra A, Arruga J, Artuch R, López-Gallardo E, Bayona-Bafaluy MP, Montoya J, Ruiz-Pesini E. The Decrease in Mitochondrial DNA Mutation Load Parallels Visual Recovery in a Leber Hereditary Optic Neuropathy Patient. Front Neurosci 2018; 12:61. [PMID: 29479304 PMCID: PMC5811516 DOI: 10.3389/fnins.2018.00061] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/24/2018] [Indexed: 11/13/2022] Open
Abstract
The onset of Leber hereditary optic neuropathy is relatively rare in childhood and, interestingly, the rate of spontaneous visual recovery is very high in this group of patients. Here, we report a child harboring a rare pathological mitochondrial DNA mutation, present in heteroplasmy, associated with the disease. A patient follow-up showed a rapid recovery of the vision accompanied by a decrease of the percentage of mutated mtDNA. A retrospective study on the age of recovery of all childhood-onset Leber hereditary optic neuropathy patients reported in the literature suggested that this process was probably related with pubertal changes.
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Affiliation(s)
- Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.,Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Mariona Vidal
- Servicio de Oftalmología Pediátrica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Carmen Hernández-Ainsa
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain
| | - Cristina Ruiz-Ruiz
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - Daniel Woods
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - Ana Morales-Becerra
- Servicio de Oftalmología Pediátrica, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Jorge Arruga
- Servicio de Oftalmología, Hospital Universitario de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Barcelona, Spain.,Servicio de Bioquímica, Hospital Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.,Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - M Pilar Bayona-Bafaluy
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.,Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Barcelona, Spain
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.,Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain.,Centro de Investigaciones Biomédicas En Red de Enfermedades Raras (CIBERER), Barcelona, Spain.,Fundación ARAID, Zaragoza, Spain
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Mordel P, Schaeffer S, Dupas Q, Laville MA, Gérard M, Chapon F, Allouche S. A 2 bp deletion in the mitochondrial ATP 6 gene responsible for the NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome. Biochem Biophys Res Commun 2017; 494:133-137. [PMID: 29054413 DOI: 10.1016/j.bbrc.2017.10.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 10/13/2017] [Indexed: 01/12/2023]
Abstract
Mitochondrial (mt) DNA-associated NARP (neurogenic muscle weakness, ataxia, and retinitis pigmentosa) syndrome is due to mutation in the MT-ATP6 gene. We report the case of a 18-year-old man who presented with deafness, a myoclonic epilepsy, muscle weakness since the age of 10 and further developed a retinitis pigmentosa and ataxia. The whole mtDNA analysis by next-generation sequencing revealed the presence of the 2 bp microdeletion m.9127-9128 del AT in the ATP6 gene at 82% heteroplasmy in muscle and to a lower load in blood (10-20%) and fibroblasts (50%). Using the patient's fibroblasts, we demonstrated a 60% reduction of the oligomycin-sensitive ATPase hydrolytic activity, a 40% decrease in the ATP synthesis and determination of the mitochondrial membrane potential using the fluorescent probe tetramethylrhodamine, ethyl ester indicated a significant reduction in oligomycin sensitivity. In conclusion, we demonstrated that this novel AT deletion in the ATP6 gene is pathogenic and responsible for the NARP syndrome.
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Affiliation(s)
- Patrick Mordel
- Normandie Univ, UNICAEN, CHU Caen, Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, Caen, F-14032, France
| | | | - Quentin Dupas
- Normandie Univ, UNICAEN, CHU Caen, Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, Caen, F-14032, France
| | | | - Marion Gérard
- CHU de Caen, Department of medical genetics, Caen, F-14032, France
| | - Françoise Chapon
- CHU de Caen, Neuromuscular Competence Center, Caen, F-14032, France; CHU de Caen, Department of Pathology, Caen, F-14032, France
| | - S Allouche
- Normandie Univ, UNICAEN, CHU Caen, Signalisation, électrophysiologie et imagerie des lésions d'ischémie-reperfusion myocardique, Caen, F-14032, France; CHU de Caen, Department of biochemistry, Caen, F-14032, France.
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29
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Jackson CB, Hahn D, Schröter B, Richter U, Battersby BJ, Schmitt-Mechelke T, Marttinen P, Nuoffer JM, Schaller A. A novel mitochondrial ATP6 frameshift mutation causing isolated complex V deficiency, ataxia and encephalomyopathy. Eur J Med Genet 2017; 60:345-351. [PMID: 28412374 DOI: 10.1016/j.ejmg.2017.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 04/03/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
We describe a novel frameshift mutation in the mitochondrial ATP6 gene in a 4-year-old girl associated with ataxia, microcephaly, developmental delay and intellectual disability. A heteroplasmic frameshift mutation in the MT-ATP6 gene was confirmed in the patient's skeletal muscle and blood. The mutation was not detectable in the mother's DNA extracted from blood or buccal cells. Enzymatic and oxymetric analysis of the mitochondrial respiratory system in the patients' skeletal muscle and skin fibroblasts demonstrated an isolated complex V deficiency. Native PAGE with subsequent immunoblotting for complex V revealed impaired complex V assembly and accumulation of ATPase subcomplexes. Whilst northern blotting confirmed equal presence of ATP8/6 mRNA, metabolic 35S-labelling of mitochondrial translation products showed a severe depletion of the ATP6 protein together with aberrant translation product accumulation. In conclusion, this novel isolated complex V defect expands the clinical and genetic spectrum of mitochondrial defects of complex V deficiency. Furthermore, this work confirms the benefit of native PAGE as an additional diagnostic method for the identification of OXPHOS defects, as the presence of complex V subcomplexes is associated with pathogenic mutations of mtDNA.
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Affiliation(s)
- Christopher B Jackson
- Institute of Clinical Chemistry, University Hospital Bern, Switzerland; Research Programs for Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Finland.
| | - Dagmar Hahn
- Institute of Clinical Chemistry, University Hospital Bern, Switzerland
| | - Barbara Schröter
- Department of Neuropaediatrics, Children's Hospital, Cantonal Hospital Lucerne, Switzerland.
| | - Uwe Richter
- Institute of Biotechnology, University of Helsinki, Finland.
| | | | - Thomas Schmitt-Mechelke
- Department of Neuropaediatrics, Children's Hospital, Cantonal Hospital Lucerne, Switzerland.
| | - Paula Marttinen
- Institute of Biotechnology, University of Helsinki, Finland.
| | - Jean-Marc Nuoffer
- Institute of Clinical Chemistry, University Hospital Bern, Switzerland.
| | - André Schaller
- Division of Human Genetics, Bern, University Hospital Bern, Switzerland.
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30
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López-Gallardo E, Llobet L, Emperador S, Montoya J, Ruiz-Pesini E. Effects of Tributyltin Chloride on Cybrids with or without an ATP Synthase Pathologic Mutation. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:1399-405. [PMID: 27129022 PMCID: PMC5010394 DOI: 10.1289/ehp182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/27/2015] [Accepted: 04/13/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND The oxidative phosphorylation system (OXPHOS) includes nuclear chromosome (nDNA)- and mitochondrial DNA (mtDNA)-encoded polypeptides. Many rare OXPHOS disorders, such as striatal necrosis syndromes, are caused by genetic mutations. Despite important advances in sequencing procedures, causative mutations remain undetected in some patients. It is possible that etiologic factors, such as environmental toxins, are the cause of these cases. Indeed, the inhibition of a particular enzyme by a poison could imitate the biochemical effects of pathological mutations in that enzyme. Moreover, environmental factors can modify the penetrance or expressivity of pathological mutations. OBJECTIVES We studied the interaction between mitochondrially encoded ATP synthase 6 (p.MT-ATP6) subunit and an environmental exposure that may contribute phenotypic differences between healthy individuals and patients suffering from striatal necrosis syndromes or other mitochondriopathies. METHODS We analyzed the effects of the ATP synthase inhibitor tributyltin chloride (TBTC), a widely distributed environmental factor that contaminates human food and water, on transmitochondrial cell lines with or without an ATP synthase mutation that causes striatal necrosis syndrome. Doses were selected based on TBTC concentrations previously reported in human whole blood samples. RESULTS TBTC modified the phenotypic effects caused by a pathological mtDNA mutation. Interestingly, wild-type cells treated with this xenobiotic showed similar bioenergetics when compared with the untreated mutated cells. CONCLUSIONS In addition to the known genetic causes, our findings suggest that environmental exposure to TBTC might contribute to the etiology of striatal necrosis syndromes. CITATION López-Gallardo E, Llobet L, Emperador S, Montoya J, Ruiz-Pesini E. 2016. Effects of tributyltin chloride on cybrids with or without an ATP synthase pathologic mutation. Environ Health Perspect 124:1399-1405; http://dx.doi.org/10.1289/EHP182.
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Affiliation(s)
- Ester López-Gallardo
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
| | - Laura Llobet
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
| | - Sonia Emperador
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
| | - Julio Montoya
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
- Address correspondence to E. Ruiz-Pesini, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail: , or J. Montoya, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail:
| | - Eduardo Ruiz-Pesini
- Departamento de Bioquímica, Biología Molecular y Celular,
- Instituto de Investigación Sanitaria de Aragón,
- CIBER de Enfermedades Raras (CIBERER), and
- Fundación ARAID, Universidad de Zaragoza, Zaragoza, Spain
- Address correspondence to E. Ruiz-Pesini, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail: , or J. Montoya, Departamento de Bioquímica, Biología Molecular y Celular, Universidad de Zaragoza. C/ Miguel Servet, 177. 50013-Zaragoza, Spain. Telephone: 34-976761640. E-mail:
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