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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Tagliani S, Malaventura C, Ceccato C, Parmeggiani F, Suppiej A. Leber Mitochondrial Optic Neuropathy in Pediatric Females With Focus on Very Early Onset Cases. J Child Neurol 2023; 38:5-15. [PMID: 36659874 DOI: 10.1177/08830738221149962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The aim of this study was to describe the phenotype of Leber hereditary optic neuropathy occurring in pediatric females. This disease generally affects young adult males, but it can occur also in females, and research data in this population is lacking. The very early onset can challenge the diagnosis and delay treatment. We searched PubMed through February 2021 and identified 226 pediatric females with genetically confirmed Leber hereditary optic neuropathy and added a new case of a 3-year-old female. The male-female ratio was 1.8:1; the mean onset age in females was 11 years with the onset at 3 years of age occurring in 3 females only. Acute onset with mild visual impairment was the most common presentation, associated with optic disc edema in 16%. Differential diagnoses are pseudotumor cerebri, optic nerve drusen and optic neuritis. The outcome is poor with partial recovery in 50%, despite some receiving Idebenone therapy.
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Affiliation(s)
- Sara Tagliani
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy
| | - Cristina Malaventura
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy
| | | | - Francesco Parmeggiani
- Department of Translational Medicine and for Romagna, 9299University of Ferrara, Ferrara, Italy.,ERN-EYE Network - Center for Retinitis Pigmentosa of Veneto Region, 196013Camposampiero Hospital, Padova, Italy
| | - Agnese Suppiej
- Department of Medical Sciences, Pediatric Section, University Hospital of Ferrara, Ferrara, Italy.,87812Robert Hollman Foundation, Padova, Italy.,ERN-EYE Network - Center for Retinitis Pigmentosa of Veneto Region, 196013Camposampiero Hospital, Padova, Italy
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Moreno-Loshuertos R, Movilla N, Marco-Brualla J, Soler-Agesta R, Ferreira P, Enríquez JA, Fernández-Silva P. A Mutation in Mouse MT-ATP6 Gene Induces Respiration Defects and Opposed Effects on the Cell Tumorigenic Phenotype. Int J Mol Sci 2023; 24. [PMID: 36674816 DOI: 10.3390/ijms24021300] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Nowak-Malczewska DM, Karolak JA, Swierkowska J, Jaworska MM, Kulinska KI, Polakowski P, Rydzanicz M, Ploski R, Szaflik JP, Gajecka M. Changes in Nuclear Gene Expression Related to Mitochondrial Function Affect Extracellular Matrix, Collagens, and Focal Adhesion in Keratoconus. Transl Vis Sci Technol 2021; 10:6. [PMID: 34478492 PMCID: PMC8419871 DOI: 10.1167/tvst.10.11.6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Purpose Mitochondrial DNA (mtDNA) abnormalities were previously found to be causative in the pathogenesis of various diseases. Here, comprehensive mitochondrial and nuclear sequence and transcript analyses, along with analyses of the methylation aspects of nuclear genes related to mitochondrial function, were performed in patients with keratoconus (KTCN) to evaluate their contribution to the KTCN pathogenesis. Methods Blood mtDNA of 42 KTCN and 51 non-KTCN individuals was Sanger sequenced and analyzed along with the previously obtained corneal RNA-sequencing data of 20 KTCN and 21 non-KTCN individuals. In addition, the expression and methylation of mtDNA genes and 1223 mitochondria-related nuclear genes were evaluated. Results The mtDNA sequence alterations detected in blood coincided with variants identified in transcripts of the matched corneal tissues. In KTCN corneas, 97 mitochondria-related genes were deregulated, including TGFB1, P4HB, and BCL2, which are involved in the extracellular matrix (ECM) organization, collagen formation, and focal adhesion pathways. No changes in the expression of mtDNA transcripts and no differentially methylated genes among the assessed mitochondrial–nuclear gene sets were found. Conclusions The absence of corneal-specific mtDNA variants indicates that there is no direct relationship between mitochondrial sequence variability and KTCN phenotype in the studied individuals. However, the identified KTCN-specific transcriptomic alterations of the nuclear genes directly related to the mitochondria functioning point to their possible involvement in the ECM organization, collagen formation, and focal adhesion. Translational Relevance The identification of abnormalities within nuclear genes regulating ECM formation, collagen synthesis, and/or focal adhesion may form the basis of future treatment strategies or predict the progression of corneal changes in KTCN.
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Affiliation(s)
- Dorota M Nowak-Malczewska
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland.,Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
| | - Justyna A Karolak
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
| | | | - Marcelina M Jaworska
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Karolina I Kulinska
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Piotr Polakowski
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | | | - Rafal Ploski
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | - Jacek P Szaflik
- Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
| | - Marzena Gajecka
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland.,Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
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Rovcanin B, Jancic J, Samardzic J, Rovcanin M, Nikolic B, Ivancevic N, Novakovic I, Kostic V. In silico model of mtDNA mutations effect on secondary and 3D structure of mitochondrial rRNA and tRNA in Leber's hereditary optic neuropathy. Exp Eye Res 2020; 201:108277. [PMID: 32991883 DOI: 10.1016/j.exer.2020.108277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 09/05/2020] [Accepted: 09/25/2020] [Indexed: 02/03/2023]
Abstract
The Leber's hereditary optic neuropathy (LHON) is a rare disease caused by mitochondrial DNA (mtDNA) mutations. Beside primary mutations, the effect of secondary mtDNA mutations in still unclear. We examined the effect of secondary mtDNA mutations on secondary structure of different mitochondrial RNAs. Whole mitochondrial genome sequence of LHON patients has been obtained from in six non related pedigrees by Sanger sequencing method. The effect of mutations located in mitochondrial RNA genes was examined by creating in silico models of RNA secondary and regional 3D structure, accompanied by sequence conservation analysis. All three primary LHON mutations (m.3460G>A, m.11778G>A and m.14484 T>C) were revealed in study families. Four mutations in MT-RNR1 gene (m.750A>G, m.956delC, m.1438A>G and m.1555A>G) were identified and only an m.1555A>G causes significant changes of secondary structure of mitochondrial 12S ribosomal RNA (rRNA), while it is the only mutation which does not alter its 3D structure. Five mutations (m.1811A>G, m.2706A>G, m.2831G>A, m.3010G>A and m.3197T>C) were discovered in MT-RNR2 gene and all of them induced substantial alterations of mitochondrial 16S rRNA secondary structure. Significant changes of mitochondrial 16S rRNA 3D structure are caused by m.1811A>G, m.2706A>G, m.3010G>A and m.3197T>C. A single insertion variant (m.15986insG) has been found in the MT-TP gene which encodes mitochondrial transfer RNA for Proline (tRNA Pro). This mutation does not cause substantial changes of tRNA for Proline secondary structure, while the 3D geometry remains without major changes. Most of the mutation loci exhibited high level of sequence conservation. Presence of multiple mutations in a single family appears to cause more extensive changes in mitochondrial 12S and 16S rRNA, then their individual influence. The effect of discovered mutations on in silico modelled RNA structure is in a significant correlation with the present knowledge about the potential of these mutation to participate in the pathophysiology of LHON and other human diseases. The presence of certain multiple mitochondrial RNA mutations could be a possible explanation of LHON clinical presentation in some families. All revealed mutations have been evaluated for the first time in terms of in silico structural modelling. The application of bioinformatics tools such as secondary and 3D RNA structure prediction can have a great advantage in better understanding of the molecular standpoint of the LHON pathophysiology and clinical phenotype.
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Affiliation(s)
- Branislav Rovcanin
- Center for Endocrine Surgery, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
| | - Jasna Jancic
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Janko Samardzic
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia; Institute of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Marija Rovcanin
- The Obstetrics and Gynecology Clinic Narodni Front, Belgrade, Serbia
| | - Blazo Nikolic
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Nikola Ivancevic
- Clinic of Neurology and Psychiatry for Children and Youth, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Ivana Novakovic
- Institute for Human Genetics, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Vladimir Kostic
- Clinic of Neurology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
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Mani S, Rao SN, Kranthi Kumar M. Genetic heterogeneity of mitochondrial genome in thiamine deficient Leigh syndrome patients. J Neurol Sci 2019; 404:91-100. [DOI: 10.1016/j.jns.2019.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/03/2019] [Accepted: 07/08/2019] [Indexed: 10/26/2022]
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Šileikytė J, Forte M. The Mitochondrial Permeability Transition in Mitochondrial Disorders. Oxid Med Cell Longev 2019; 2019:3403075. [PMID: 31191798 PMCID: PMC6525910 DOI: 10.1155/2019/3403075] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/15/2019] [Accepted: 04/01/2019] [Indexed: 12/22/2022]
Abstract
Mitochondrial permeability transition pore (PTP), a (patho)physiological phenomenon discovered over 40 years ago, is still not completely understood. PTP activation results in a formation of a nonspecific channel within the inner mitochondrial membrane with an exclusion size of 1.5 kDa. PTP openings can be transient and are thought to serve a physiological role to allow quick Ca2+ release and/or metabolite exchange between mitochondrial matrix and cytosol or long-lasting openings that are associated with pathological conditions. While matrix Ca2+ and oxidative stress are crucial in its activation, the consequence of prolonged PTP opening is dissipation of the inner mitochondrial membrane potential, cessation of ATP synthesis, bioenergetic crisis, and cell death-a primary characteristic of mitochondrial disorders. PTP involvement in mitochondrial and cellular demise in a variety of disease paradigms has been long appreciated, yet the exact molecular entity of the PTP and the development of potent and specific PTP inhibitors remain areas of active investigation. In this review, we will (i) summarize recent advances made in elucidating the molecular nature of the PTP focusing on evidence pointing to mitochondrial FoF1-ATP synthase, (ii) summarize studies aimed at discovering novel PTP inhibitors, and (iii) review data supporting compromised PTP activity in specific mitochondrial diseases.
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Affiliation(s)
- Justina Šileikytė
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Michael Forte
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
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Spangenberg L, Graña M, Mansilla S, Martínez J, Tapié A, Greif G, Montano N, Vaglio A, Gueçaimburú R, Robello C, Castro L, Quijano C, Raggio V, Naya H. Deep sequencing discovery of causal mtDNA mutations in a patient with unspecific neurological disease. Mitochondrion 2019; 46:337-344. [DOI: 10.1016/j.mito.2018.09.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 06/30/2018] [Accepted: 09/11/2018] [Indexed: 11/15/2022]
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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] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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Flaquer A, Heinzmann A, Rospleszcz S, Mailaparambil B, Dietrich H, Strauch K, Grychtol R. Association study of mitochondrial genetic polymorphisms in asthmatic children. Mitochondrion 2014; 14:49-53. [PMID: 24270090 DOI: 10.1016/j.mito.2013.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 09/03/2013] [Accepted: 11/13/2013] [Indexed: 11/21/2022]
Abstract
It has been suggested that mitochondrial dysfunction plays a role in the pathogenesis of asthma. To test whether mitochondrial variants influence the risk of asthma, we analyzed 16,158 mtSNPs in a sample of 372 asthmatic children and 395 healthy children using the DNA pooling technique and genome wide association analysis. Stratified analysis by sex was performed to explain the differences observed between sexes in the etiology of asthma. Different variants were detected to be significant in the sample of girls and boys with the smallest adjusted p values being 1.4 × 10(-09) (mt5295) and 3.6 × 10(-12) (mt16158), respectively. Most of the significant locations found in boys are within the CYB gene and the non-coding region. For girls, most of the significant mtSNPs lie within NADH-dehydrogenase-subunits. The variants reported here have not previously been described in connection with asthma. Although further studies in other cohorts are needed to confirm these findings our study highlights the importance of the mitochondria among the factors that contribute to the risk of asthma.
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Blanco-Grau A, Bonaventura-Ibars I, Coll-Cantí J, Melià MJ, Martinez R, Martínez-Gallo M, Andreu AL, Pinós T, García-Arumí E. Identification and biochemical characterization of the novel mutation m.8839G>C in the mitochondrial ATP6 gene associated with NARP syndrome. Genes Brain Behav 2013; 12:812-20. [PMID: 24118886 DOI: 10.1111/gbb.12089] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 12/21/2022]
Abstract
Mutations in the ATP6 gene are reported to be associated with Leber hereditary optic neuropathy, bilateral striatal necrosis, coronary atherosclerosis risk and neuropathy, ataxia and retinitis pigmentosa (NARP)/maternally inherited Leigh syndromes. Here, we present a patient with NARP syndrome, in whom a previously undescribed mutation was detected in the ATP6 gene: m.8839G>C. Several observations support the concept that m.8839G>C is pathogenically involved in the clinical phenotype of this patient: (1) the mutation was heteroplasmic in muscle; (2) mutation load was higher in the symptomatic patient than in the asymptomatic carriers; (3) cybrids carrying this mutation presented lower cell proliferation, increased mitochondrial DNA (mtDNA) copy number, increased steady-state OxPhos protein levels and decreased mitochondrial membrane potential with respect to isogenic wild-type cybrids; (4) this change was not observed in 2959 human mtDNAs from different mitochondrial haplogroups; (5) the affected amino acid was conserved in all the ATP6 sequences analyzed; and (6) using in silico prediction, the mutation was classified as 'probably damaging'. However, measurement of ATP synthesis showed no differences between wild-type and mutated cybrids. Thus, we suggest that m.8839G>C may lower the efficiency between proton translocation within F0 and F1 rotation, required for ATP synthesis. Further experiments are needed to fully characterize the molecular mechanisms involved in m.8839G>C pathogenicity.
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Affiliation(s)
- A Blanco-Grau
- Departament de Patología Mitocondrial i Neuromuscular, Universitari Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona
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Rezvani Z, Didari E, Arastehkani A, Ghodsinejad V, Aryani O, Kamalidehghan B, Houshmand M. Fifteen novel mutations in the mitochondrial NADH dehydrogenase subunit 1, 2, 3, 4, 4L, 5 and 6 genes from Iranian patients with Leber's hereditary optic neuropathy (LHON). Mol Biol Rep 2013; 40:6837-41. [PMID: 24158608 DOI: 10.1007/s11033-013-2801-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 09/26/2013] [Indexed: 01/11/2023]
Abstract
Leber's hereditary optic neuropathy (LHON) is an optic nerve dysfunction resulting from mutations in mitochondrial DNA (mtDNA), which is transmitted in a maternal pattern of inheritance. It is caused by three primary point mutations: G11778A, G3460A and T14484C; in the mitochondrial genome. These mutations are sufficient to induce the disease, accounting for the majority of LHON cases, and affect genes that encode for the different subunits of mitochondrial complexes I and III of the mitochondrial respiratory chain. Other mutations are secondary mutations associated with the primary mutations. The purpose of this study was to determine MT-ND variations in Iranian patients with LHON. In order to determine the prevalence and distribution of mitochondrial mutations in the LHON patients, their DNA was studied using PCR and DNA sequencing analysis. Sequencing of MT-ND genes from 35 LHON patients revealed a total of 44 nucleotide variations, in which fifteen novel variations-A14020G, A13663G, C10399T, C4932A, C3893G, C10557A, C12012A, C13934T, G4596A, T12851A, T4539A, T4941A, T13255A, T14353C and del A 4513-were observed in 27 LHON patients. However, eight patients showed no variation in the ND genes. These mutations contribute to the current database of mtDNA polymorphisms in LHON patients and may facilitate the definition of disease-related mutations in human mtDNA. This research may help to understand the disease mechanism and open up new diagnostic opportunities for LHON.
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Affiliation(s)
- Zahra Rezvani
- Department of Biotechnology, Faculty of Chemistry, University of Kashan, Kashan, Iran
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Tranah GJ, Lam ET, Katzman SM, Nalls MA, Zhao Y, Evans DS, Yokoyama JS, Pawlikowska L, Kwok PY, Mooney S, Kritchevsky S, Goodpaster BH, Newman AB, Harris TB, Manini TM, Cummings SR. Mitochondrial DNA sequence variation is associated with free-living activity energy expenditure in the elderly. Biochim Biophys Acta 2012; 1817:1691-700. [PMID: 22659402 DOI: 10.1016/j.bbabio.2012.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 05/19/2012] [Accepted: 05/24/2012] [Indexed: 01/11/2023]
Abstract
The decline in activity energy expenditure underlies a range of age-associated pathological conditions, neuromuscular and neurological impairments, disability, and mortality. The majority (90%) of the energy needs of the human body are met by mitochondrial oxidative phosphorylation (OXPHOS). OXPHOS is dependent on the coordinated expression and interaction of genes encoded in the nuclear and mitochondrial genomes. We examined the role of mitochondrial genomic variation in free-living activity energy expenditure (AEE) and physical activity levels (PAL) by sequencing the entire (~16.5 kilobases) mtDNA from 138 Health, Aging, and Body Composition Study participants. Among the common mtDNA variants, the hypervariable region 2 m.185G>A variant was significantly associated with AEE (p=0.001) and PAL (p=0.0005) after adjustment for multiple comparisons. Several unique nonsynonymous variants were identified in the extremes of AEE with some occurring at highly conserved sites predicted to affect protein structure and function. Of interest is the p.T194M, CytB substitution in the lower extreme of AEE occurring at a residue in the Qi site of complex III. Among participants with low activity levels, the burden of singleton variants was 30% higher across the entire mtDNA and OXPHOS complex I when compared to those having moderate to high activity levels. A significant pooled variant association across the hypervariable 2 region was observed for AEE and PAL. These results suggest that mtDNA variation is associated with free-living AEE in older persons and may generate new hypotheses by which specific mtDNA complexes, genes, and variants may contribute to the maintenance of activity levels in late life.
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Affiliation(s)
- Gregory J Tranah
- California Pacific Medical Center Research Institute, San Francisco, San Francisco, CA 94107, USA.
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Jonckheere AI, Smeitink JAM, Rodenburg RJT. Mitochondrial ATP synthase: architecture, function and pathology. J Inherit Metab Dis 2012; 35:211-25. [PMID: 21874297 PMCID: PMC3278611 DOI: 10.1007/s10545-011-9382-9] [Citation(s) in RCA: 355] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 07/22/2011] [Accepted: 07/27/2011] [Indexed: 12/16/2022]
Abstract
Human mitochondrial (mt) ATP synthase, or complex V consists of two functional domains: F(1), situated in the mitochondrial matrix, and F(o), located in the inner mitochondrial membrane. Complex V uses the energy created by the proton electrochemical gradient to phosphorylate ADP to ATP. This review covers the architecture, function and assembly of complex V. The role of complex V di-and oligomerization and its relation with mitochondrial morphology is discussed. Finally, pathology related to complex V deficiency and current therapeutic strategies are highlighted. Despite the huge progress in this research field over the past decades, questions remain to be answered regarding the structure of subunits, the function of the rotary nanomotor at a molecular level, and the human complex V assembly process. The elucidation of more nuclear genetic defects will guide physio(patho)logical studies, paving the way for future therapeutic interventions.
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Affiliation(s)
- An I. Jonckheere
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, 656 Laboratory for Genetic, Endocrine, and Metabolic Disorders, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Jan A. M. Smeitink
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, 656 Laboratory for Genetic, Endocrine, and Metabolic Disorders, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Richard J. T. Rodenburg
- Department of Pediatrics, Nijmegen Center for Mitochondrial Disorders, 656 Laboratory for Genetic, Endocrine, and Metabolic Disorders, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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Houshmand M, Kasraie S, Etemad Ahari S, Moin M, Bahar M, Zamani A. Investigation of tRNA and ATPase 6/8 gene mutations in Iranian ataxia telangiectasia patients. Arch Med Sci 2011; 7:523-7. [PMID: 22295039 PMCID: PMC3258747 DOI: 10.5114/aoms.2011.23424] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 07/01/2010] [Accepted: 10/14/2010] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Ataxia telangiectasia (AT) is a rare human neurodegenerative autosomal recessive multisystem disease. AT is the result of mutations in the AT-mutated (ATM) gene. ATM protein is required for radiation-induced apoptosis and acts before mitochondrial collapse. The tRNA genes are considered one of the hot spots for mutations causing mitochondrial disorders. Due to the important role of ATM in apoptosis and its effect on the cell cycle it might be possible that it has a central role in mtDNA mutations. On the other hand, the tRNA(Lys/Leu) gene and also ATPase6 and ATPase8 genes are important for many mitochondrial diseases and many causative mutations have been reported from these genes. MATERIAL AND METHODS In the present research, we performed mutation screening for these genes in 20 patients who were diagnosed with ataxia telangiectasia by a PCR sequencing method. RESULTS The results showed a significant level of mtDNA variations in AT patients. Among 20 patients in this study, 12 patients (60%) were detected with point mutations, among which 8 mutations (40%) belonged to the MT-ATP6 gene. There was probably a second effect of mtDNA mutations in AT disease and mtDNA plays a main role in establishment of AT. CONCLUSIONS MtDNA mutations might be responsible for the decline of mitochondrial function in AT patients. Mitochondrial investigation can help to understand the mechanism of damage in AT disease.
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Affiliation(s)
- Massoud Houshmand
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Sadaf Kasraie
- Islamic Azad University, Science and Research, Tehran, Iran
| | | | - Mostafa Moin
- Immunology, Asthma and Allergy Research Institute, Tehran, Iran
| | - Mohammadali Bahar
- Immunology Research Center No 5, Tehran University of Medical Sciences, Iran
| | - Akram Zamani
- Genetic Diagnostic Department, Special Medical Center, Tehran, Iran
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Koilkonda RD, Guy J. Leber's Hereditary Optic Neuropathy-Gene Therapy: From Benchtop to Bedside. J Ophthalmol 2011; 2011:179412. [PMID: 21253496 DOI: 10.1155/2011/179412] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/07/2010] [Accepted: 11/12/2010] [Indexed: 02/06/2023] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternally transmitted disorder caused by point mutations in mitochondrial DNA (mtDNA). Most cases are due to mutations in genes encoding subunits of the NADH-ubiquinone oxidoreductase that is Complex I of the electron transport chain (ETC). These mutations are located at nucleotide positions 3460, 11778, or 14484 in the mitochondrial genome. The disease is characterized by apoplectic, bilateral, and severe visual loss. While the mutated mtDNA impairs generation of ATP by all mitochondria, there is only a selective loss of retinal ganglion cells and degeneration of optic nerve axons. Thus, blindness is typically permanent. Half of the men and 10% of females who harbor the pathogenic mtDNA mutation actually develop the phenotype. This incomplete penetrance and gender bias is not fully understood. Additional mitochondrial and/or nuclear genetic factors may modulate the phenotypic expression of LHON. In a population-based study, the mtDNA background of haplogroup J was associated with an inverse relationship of low-ATP generation and increased production of reactive oxygen species (ROS). Effective therapy for LHON has been elusive. In this paper, we describe the findings of pertinent published studies and discuss the controversies of potential strategies to ameliorate the disease.
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Crispim D, Estivalet AAF, Roisenberg I, Gross JL, Canani LH. Prevalence of 15 mitochondrial DNA mutations among type 2 diabetic patients with or without clinical characteristics of maternally inherited diabetes and deafness. ACTA ACUST UNITED AC 2009; 52:1228-35. [PMID: 19169474 DOI: 10.1590/s0004-27302008000800005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 09/23/2008] [Indexed: 11/21/2022]
Abstract
The aim of the present study is to investigate the prevalence of ten described mitochondrial DNA (mtDNA) mutations in patients with type 2 diabetes, and search for new mutations in four mtDNA genes in a subgroup of patients with characteristics of maternally inherited diabetes and deafness (MIDD). These mutations were investigated in 407 type 2 diabetic patients without characteristics of mitochondrial diabetes ('classical' type 2 diabetes group) and in 38 type 2 diabetic patients with characteristics suggestive of MIDD. Through sequencing of four mtDNA genes in MIDD patients, we selected five others potentially pathogenic mutations that were also screened in the remaining patients. Overall, the frequency of the fifteen analyzed mutations was 36.84% in the MIDD group and 2.45% in the 'classical' type 2 diabetes group (p < 0.001). In conclusion, our study reinforces the importance of mtDNA mutations in the pathogenesis of MIDD.
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Affiliation(s)
- Daisy Crispim
- Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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18
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Bandelt HJ, Yao YG, Salas A. The search of 'novel' mtDNA mutations in hypertrophic cardiomyopathy: MITOMAPping as a risk factor. Int J Cardiol 2007; 126:439-42. [PMID: 17482693 DOI: 10.1016/j.ijcard.2007.02.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 02/16/2007] [Indexed: 11/24/2022]
Abstract
MITOMAP is by far the most frequently cited Web resource that is referred to in substantiating novelty of an mtDNA mutation. This database, as is now known, has quite an incomplete coverage of the mtDNA mutations from the literature. This circumstance has seduced many scholars of medical genetics in the past to claim novelty of rather 'worn-out' mtDNA mutations. What is, however, really novel in the field is that researchers take advantage of this situation and deliberately suppress information from other sources, as it appears to have occurred in two recently published cases of hypertrophic cardiomyopathy.
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Jacobs L, Gerards M, Chinnery P, Dumoulin J, de Coo I, Geraedts J, Smeets H. mtDNA point mutations are present at various levels of heteroplasmy in human oocytes. Mol Hum Reprod 2007; 13:149-54. [PMID: 17259224 DOI: 10.1093/molehr/gal112] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Little is known about the load of mutations and polymorphisms in the mitochondrial DNA (mtDNA) of human oocytes and the possible effect these mutations may have during life. To investigate this, we optimised at the single cell level the recently developed method to screen the entire mtDNA for mainly heteroplasmic mutations by denaturing high performance liquid chromatography analysis. This method is sensitive (approximately 1% heteroplasmy detectable), specific and rapid. The entire mtDNA of 26 oocytes of 13 women was screened by this method. Ten different heteroplasmic mutations, of which only one was located in the D-loop and two were observed twice, were detected in seven oocytes with mutation loads ranging from <5% to 50%. From eight women >1 oocyte was received and in four of them heteroplasmic differences between oocytes of the same woman were observed. In one of these four, two homoplasmic D-loop variants were also detected. Additionally, four oocytes of a single woman were sequenced using the MitoChip (which lacks the D-loop region), but all sequences were identical. It is concluded that heteroplasmic mtDNA mutations are common in oocytes and that, depending on the position and mutation load, they might increase the risk of developing OXPHOS disease early or later in life.
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Affiliation(s)
- Lorraine Jacobs
- Department of Genetics and Cell Biology, University of Maastricht, The Netherlands
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Bandelt HJ, Yao YG, Salas A, Kivisild T, Bravi CM. High penetrance of sequencing errors and interpretative shortcomings in mtDNA sequence analysis of LHON patients. Biochem Biophys Res Commun 2006; 352:283-91. [PMID: 17123466 DOI: 10.1016/j.bbrc.2006.10.131] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Accepted: 10/25/2006] [Indexed: 11/18/2022]
Abstract
For identifying mutation(s) that are potentially pathogenic it is essential to determine the entire mitochondrial DNA (mtDNA) sequences from patients suffering from a particular mitochondrial disease, such as Leber hereditary optic neuropathy (LHON). However, such sequencing efforts can, in the worst case, be riddled with errors by imposing phantom mutations or misreporting variant nucleotides, and moreover, by inadvertently regarding some mutations as novel and pathogenic, which are actually known to define minor haplogroups. Under such circumstances it remains unclear whether the disease-associated mutations would have been determined adequately. Here, we re-analyse four problematic LHON studies and propose guidelines by which some of the pitfalls could be avoided.
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