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Palmieri F, Monné M. Discoveries, metabolic roles and diseases of mitochondrial carriers: A review. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2362-78. [PMID: 26968366 DOI: 10.1016/j.bbamcr.2016.03.007] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 12/25/2022]
Abstract
Mitochondrial carriers (MCs) are a superfamily of nuclear-encoded proteins that are mostly localized in the inner mitochondrial membrane and transport numerous metabolites, nucleotides, cofactors and inorganic anions. Their unique sequence features, i.e., a tripartite structure, six transmembrane α-helices and a three-fold repeated signature motif, allow MCs to be easily recognized. This review describes how the functions of MCs from Saccharomyces cerevisiae, Homo sapiens and Arabidopsis thaliana (listed in the first table) were discovered after the genome sequence of S. cerevisiae was determined in 1996. In the genomic era, more than 50 previously unknown MCs from these organisms have been identified and characterized biochemically using a method consisting of gene expression, purification of the recombinant proteins, their reconstitution into liposomes and transport assays (EPRA). Information derived from studies with intact mitochondria, genetic and metabolic evidence, sequence similarity, phylogenetic analysis and complementation of knockout phenotypes have guided the choice of substrates that were tested in the transport assays. In addition, the diseases associated to defects of human MCs have been briefly reviewed. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy.
| | - Magnus Monné
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via E. Orabona 4, 70125 Bari, Italy; Department of Sciences, University of Basilicata, Via Ateneo Lucano 10, 85100 Potenza, Italy
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102
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Filosto M, Lanzi G, Nesti C, Vielmi V, Marchina E, Galvagni A, Giliani S, Santorelli FM, Padovani A. A novel mitochondrial tRNA(Ala) gene variant causes chronic progressive external ophthalmoplegia in a patient with Huntington disease. Mol Genet Metab Rep 2016; 6:70-3. [PMID: 27014581 PMCID: PMC4789388 DOI: 10.1016/j.ymgmr.2016.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 02/07/2016] [Indexed: 12/14/2022] Open
Abstract
Chronic progressive external ophthalmoplegia is a mitochondrial disorder usually caused by single or multiple mitochondrial DNA (mtDNA) deletions and, more rarely, by maternally inherited mtDNA point mutations, most frequently in tRNA genes (MTT). We report on a patient presenting with a progressive eyelid ptosis with bilateral ophthalmoparesis, dysphagia, dysphonia and mild proximal limb weakness associate with a mild movement disorder characterized by abnormal involuntary movements involving head and limbs, imbalance and gait instability. Muscle biopsy demonstrated the presence of ragged red fibers and several cytochrome-C-oxidase negative fibers. Molecular analysis showed the novel m.5613T > C heteroplasmic mutation in the mitochondrial tRNA(Ala) gene (MTTA) which disrupts a conserved site and fulfills the accepted criteria of pathogenicity. Moreover, a 38 CAG trinucleotide repeat expansion was found on the huntingtin gene, thus configuring a singular CPEO/"reduced penetrance" Huntington disease "double trouble". With this novel MTTA point mutation, we extend the spectrum of provisional pathogenic changes in this gene, which is a very rare site of pathogenic mutation, and confirm that clinical expression of these mutations is hardly ever heterogeneous, including myopathy and CPEO. Mitochondrial involvement is an emerging key determinant in the pathogenesis of Huntington disease and it is well known that mutant huntingtin influences the mitochondrial respiratory complexes II and III. A synergist effect of the HTT and MTTA mutations on respiratory chain function may be hypothesized in our patient and should be regarded as a spur for further studies on the mtDNA/HTT reciprocal interactions.
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Affiliation(s)
- Massimiliano Filosto
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
| | - Gaetana Lanzi
- Institute of Molecular Medicine “A. Nocivelli”, University Hospital “Spedali Civili”, Brescia, Italy
| | - Claudia Nesti
- Unit of Molecular Medicine, IRCCS Stella Maris, Pisa, Italy
| | - Valentina Vielmi
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
| | - Eleonora Marchina
- Division of Biology and Genetics, Department of Biomedical Sciences and Biotechnology, University of Brescia, Italy
| | - Anna Galvagni
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
| | - Silvia Giliani
- Institute of Molecular Medicine “A. Nocivelli”, University Hospital “Spedali Civili”, Brescia, Italy
| | | | - Alessandro Padovani
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
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103
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Lasserre JP, Dautant A, Aiyar RS, Kucharczyk R, Glatigny A, Tribouillard-Tanvier D, Rytka J, Blondel M, Skoczen N, Reynier P, Pitayu L, Rötig A, Delahodde A, Steinmetz LM, Dujardin G, Procaccio V, di Rago JP. Yeast as a system for modeling mitochondrial disease mechanisms and discovering therapies. Dis Model Mech 2016; 8:509-26. [PMID: 26035862 PMCID: PMC4457039 DOI: 10.1242/dmm.020438] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondrial diseases are severe and largely untreatable. Owing to the many essential processes carried out by mitochondria and the complex cellular systems that support these processes, these diseases are diverse, pleiotropic, and challenging to study. Much of our current understanding of mitochondrial function and dysfunction comes from studies in the baker's yeast Saccharomyces cerevisiae. Because of its good fermenting capacity, S. cerevisiae can survive mutations that inactivate oxidative phosphorylation, has the ability to tolerate the complete loss of mitochondrial DNA (a property referred to as ‘petite-positivity’), and is amenable to mitochondrial and nuclear genome manipulation. These attributes make it an excellent model system for studying and resolving the molecular basis of numerous mitochondrial diseases. Here, we review the invaluable insights this model organism has yielded about diseases caused by mitochondrial dysfunction, which ranges from primary defects in oxidative phosphorylation to metabolic disorders, as well as dysfunctions in maintaining the genome or in the dynamics of mitochondria. Owing to the high level of functional conservation between yeast and human mitochondrial genes, several yeast species have been instrumental in revealing the molecular mechanisms of pathogenic human mitochondrial gene mutations. Importantly, such insights have pointed to potential therapeutic targets, as have genetic and chemical screens using yeast. Summary: In this Review, we discuss the use of budding yeast to understand mitochondrial diseases and help in the search for their treatments.
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Affiliation(s)
- Jean-Paul Lasserre
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
| | - Alain Dautant
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
| | - Raeka S Aiyar
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany
| | - Roza Kucharczyk
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Annie Glatigny
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, 1 avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Déborah Tribouillard-Tanvier
- Institut National de la Santé et de la Recherche Médicale UMR1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Joanna Rytka
- Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Marc Blondel
- Institut National de la Santé et de la Recherche Médicale UMR1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest F-29200, France
| | - Natalia Skoczen
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France Department of Genetics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw 02-106, Poland
| | - Pascal Reynier
- UMR CNRS 6214-INSERM U1083, Angers 49933, Cedex 9, France Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers 49933, Cedex 9, France
| | - Laras Pitayu
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, rue Gregor Mendel, Orsay 91405, France
| | - Agnès Rötig
- Inserm U1163, Hôpital Necker-Enfants-Malades, Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 149 rue de Sèvres, Paris 75015, France
| | - Agnès Delahodde
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, rue Gregor Mendel, Orsay 91405, France
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Meyerhofstrasse 1, Heidelberg 69117, Germany Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304, USA Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305-5301, USA
| | - Geneviève Dujardin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, 1 avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Vincent Procaccio
- UMR CNRS 6214-INSERM U1083, Angers 49933, Cedex 9, France Département de Biochimie et Génétique, Centre Hospitalier Universitaire d'Angers, Angers 49933, Cedex 9, France
| | - Jean-Paul di Rago
- University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, Bordeaux F-33000, France
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104
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Khan NA, Govindaraj P, Meena AK, Thangaraj K. Mitochondrial disorders: challenges in diagnosis & treatment. Indian J Med Res 2016; 141:13-26. [PMID: 25857492 PMCID: PMC4405934 DOI: 10.4103/0971-5916.154489] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mitochondrial dysfunctions are known to be responsible for a number of heterogenous clinical presentations with multi-systemic involvement. Impaired oxidative phosphorylation leading to a decrease in cellular energy (ATP) production is the most important cause underlying these disorders. Despite significant progress made in the field of mitochondrial medicine during the last two decades, the molecular mechanisms underlying these disorders are not fully understood. Since the identification of first mitochondrial DNA (mtDNA) mutation in 1988, there has been an exponential rise in the identification of mtDNA and nuclear DNA mutations that are responsible for mitochondrial dysfunction and disease. Genetic complexity together with ever widening clinical spectrum associated with mitochondrial dysfunction poses a major challenge in diagnosis and treatment. Effective therapy has remained elusive till date and is mostly efficient in relieving symptoms. In this review, we discuss the important clinical and genetic features of mitochondrials disorders with special emphasis on diagnosis and treatment.
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Affiliation(s)
| | | | | | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular & Molecular Biology, Nizam's Institute of Medical Sciences, Hyderabad, India
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105
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Paramasivam A, Meena AK, Pedaparthi L, Jyothi V, Uppin MS, Jabeen SA, Sundaram C, Thangaraj K. Novel mutation in C10orf2 associated with multiple mtDNA deletions, chronic progressive external ophthalmoplegia and premature aging. Mitochondrion 2015; 26:81-5. [PMID: 26689116 DOI: 10.1016/j.mito.2015.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/11/2015] [Accepted: 12/11/2015] [Indexed: 11/15/2022]
Abstract
Chronic progressive external ophthalmoplegia (CPEO) is caused by defects in both mitochondrial and nuclear genes, however, the causal genetic factors in large number of patients remains undetermined. Therefore, our aim was to screen 12 unrelated patients with CPEO for mutation/multiple deletions in mtDNA and mutations in the coding regions of C10orf2, which is essential for mtDNA replication. Histopathological study of muscle biopsy revealed cytochrome c oxidase-deficient fibers and ragged blue fibers in all the patients. Long-range PCR of DNA from skeletal muscle revealed multiple mtDNA deletions in all the 12 patients. Further, sequencing coding regions of C10orf2 revealed three variants in three different patients, of which two were novel (c.1964G>A/p.G655D; c.204G>A/p.G68G) variants and one was reported (c.1052A>G/p. N351S). Sequencing of other nuclear genes that are associated with CPEO and multiple mtDNA deletions, such as; POLG1, POLG2, TK2, ANT1, DGUOK, MPV17 and RRM2B did not reveal any pathogenic mutation in patients with C10orf2 mutation. Since in silico analyses revealed p.G655D could be a potentially pathogenic and it was absent in 200 healthy controls, p.G655D could be the causative factor for CPEO. Therefore, we suggest that C10orf2 gene should be screened in CPEO individuals with multiple mtDNA deletions, which might help in prognosis of this disease and appropriate genetic counseling.
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Affiliation(s)
| | | | - Lalitha Pedaparthi
- Department of Neurology, Nizam's Institute of Medical Sciences, Hyderabad, India
| | | | - Megha S Uppin
- Department of Pathology, Nizam's Institute of Medical Sciences, Hyderabad, India
| | - Shaikh Afshan Jabeen
- Department of Neurology, Nizam's Institute of Medical Sciences, Hyderabad, India
| | - Challa Sundaram
- Department of Pathology, Nizam's Institute of Medical Sciences, Hyderabad, India
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106
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Shamseldin HE, Smith LL, Kentab A, Alkhalidi H, Summers B, Alsedairy H, Xiong Y, Gupta VA, Alkuraya FS. Mutation of the mitochondrial carrier SLC25A42 causes a novel form of mitochondrial myopathy in humans. Hum Genet 2015; 135:21-30. [PMID: 26541337 DOI: 10.1007/s00439-015-1608-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/24/2015] [Indexed: 01/08/2023]
Abstract
Myopathies are heterogeneous disorders characterized clinically by weakness and hypotonia, usually in the absence of gross dystrophic changes. Mitochondrial dysfunction is a frequent cause of myopathy. We report a simplex case born to consanguineous parents who presented with muscle weakness, lactic acidosis, and muscle changes suggestive of mitochondrial dysfunction. Combined autozygome and exome analysis revealed a missense variant in the SLC25A42 gene, which encodes an inner mitochondrial membrane protein that imports coenzyme A into the mitochondrial matrix. Zebrafish slc25a42 knockdown morphants display severe muscle disorganization and weakness. Importantly, these features are rescued by normal human SLC25A42 RNA, but not by RNA harboring the patient's variant. Our data support a potentially causal link between SLC25A42 mutation and mitochondrial myopathy in humans.
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Affiliation(s)
- Hanan E Shamseldin
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Laura L Smith
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amal Kentab
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Hisham Alkhalidi
- Department of Pathology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Brady Summers
- Department of Molecular Biophysics & Biochemistry 260 Whitney Avenue P.O. Box 208114. New Haven, CT, USA
| | - Haifa Alsedairy
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Yong Xiong
- Department of Molecular Biophysics & Biochemistry 260 Whitney Avenue P.O. Box 208114. New Haven, CT, USA
| | - Vandana A Gupta
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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107
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Zuo L, Pannell BK, Re AT, Best TM, Wagner PD. Po2 cycling protects diaphragm function during reoxygenation via ROS, Akt, ERK, and mitochondrial channels. Am J Physiol Cell Physiol 2015; 309:C759-66. [PMID: 26423578 DOI: 10.1152/ajpcell.00174.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/25/2015] [Indexed: 11/22/2022]
Abstract
Po2 cycling, often referred to as intermittent hypoxia, involves exposing tissues to brief cycles of low oxygen environments immediately followed by hyperoxic conditions. After experiencing long-term hypoxia, muscle can be damaged during the subsequent reintroduction of oxygen, which leads to muscle dysfunction via reperfusion injury. The protective effect and mechanism behind Po2 cycling in skeletal muscle during reoxygenation have yet to be fully elucidated. We hypothesize that Po2 cycling effectively increases muscle fatigue resistance through reactive oxygen species (ROS), protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and certain mitochondrial channels during reoxygenation. Using a dihydrofluorescein fluorescent probe, we detected the production of ROS in mouse diaphragmatic skeletal muscle in real time under confocal microscopy. Muscles treated with Po2 cycling displayed significantly attenuated ROS levels (n = 5; P < 0.001) as well as enhanced force generation compared with controls during reperfusion (n = 7; P < 0.05). We also used inhibitors for signaling molecules or membrane channels such as ROS, Akt, ERK, as well as chemical stimulators to close mitochondrial ATP-sensitive potassium channel (KATP) or open mitochondrial permeability transition pore (mPTP). All these blockers or stimulators abolished improved muscle function with Po2 cycling treatment. This current investigation has discovered a correlation between KATP and mPTP and the Po2 cycling pathway in diaphragmatic skeletal muscle. Thus we have identified a unique signaling pathway that may involve ROS, Akt, ERK, and mitochondrial channels responsible for Po2 cycling protection during reoxygenation conditions in the diaphragm.
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Affiliation(s)
- Li Zuo
- Radiologic Sciences and Respiratory Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio; Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio
| | - Benjamin K Pannell
- Radiologic Sciences and Respiratory Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Anthony T Re
- Radiologic Sciences and Respiratory Therapy Division, School of Health and Rehabilitation Sciences, The Ohio State University College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Thomas M Best
- Division of Sports Medicine, Department of Family Medicine, Sports Health and Performance Institute, The Ohio State University, Columbus, Ohio; and
| | - Peter D Wagner
- Department of Medicine, University of California, San Diego, La Jolla, California
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108
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Cabrera-Pérez R, Torres-Torronteras J, Vila-Julià F, Ortega FJ, Cámara Y, Barquinero J, Martí R. Prospective therapeutic approaches in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1090307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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109
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Wang X, Chen XJ. A cytosolic network suppressing mitochondria-mediated proteostatic stress and cell death. Nature 2015; 524:481-4. [PMID: 26192197 PMCID: PMC4582408 DOI: 10.1038/nature14859] [Citation(s) in RCA: 244] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 06/29/2015] [Indexed: 12/23/2022]
Abstract
Mitochondria are multifunctional organelles whose dysfunction leads to neuromuscular degeneration and ageing. The multi-functionality poses a great challenge for understanding the mechanisms by which mitochondrial dysfunction causes specific pathologies. Among the leading mitochondrial mediators of cell death are energy depletion, free radical production, defects in iron-sulfur cluster biosynthesis, the release of pro-apoptotic and non-cell-autonomous signalling molecules, and altered stress signalling. Here we identify a new pathway of mitochondria-mediated cell death in yeast. This pathway was named mitochondrial precursor over-accumulation stress (mPOS), and is characterized by aberrant accumulation of mitochondrial precursors in the cytosol. mPOS can be triggered by clinically relevant mitochondrial damage that is not limited to the core machineries of protein import. We also discover a large network of genes that suppress mPOS, by modulating ribosomal biogenesis, messenger RNA decapping, transcript-specific translation, protein chaperoning and turnover. In response to mPOS, several ribosome-associated proteins were upregulated, including Gis2 and Nog2, which promote cap-independent translation and inhibit the nuclear export of the 60S ribosomal subunit, respectively. Gis2 and Nog2 upregulation promotes cell survival, which may be part of a feedback loop that attenuates mPOS. Our data indicate that mitochondrial dysfunction contributes directly to cytosolic proteostatic stress, and provide an explanation for the association between these two hallmarks of degenerative diseases and ageing. The results are relevant to understanding diseases (for example, spinocerebellar ataxia, amyotrophic lateral sclerosis and myotonic dystrophy) that involve mutations within the anti-degenerative network.
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Affiliation(s)
- Xiaowen Wang
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
| | - Xin Jie Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210, USA
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110
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Ahmed N, Ronchi D, Comi GP. Genes and Pathways Involved in Adult Onset Disorders Featuring Muscle Mitochondrial DNA Instability. Int J Mol Sci 2015; 16:18054-76. [PMID: 26251896 PMCID: PMC4581235 DOI: 10.3390/ijms160818054] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 12/31/2022] Open
Abstract
Replication and maintenance of mtDNA entirely relies on a set of proteins encoded by the nuclear genome, which include members of the core replicative machinery, proteins involved in the homeostasis of mitochondrial dNTPs pools or deputed to the control of mitochondrial dynamics and morphology. Mutations in their coding genes have been observed in familial and sporadic forms of pediatric and adult-onset clinical phenotypes featuring mtDNA instability. The list of defects involved in these disorders has recently expanded, including mutations in the exo-/endo-nuclease flap-processing proteins MGME1 and DNA2, supporting the notion that an enzymatic DNA repair system actively takes place in mitochondria. The results obtained in the last few years acknowledge the contribution of next-generation sequencing methods in the identification of new disease loci in small groups of patients and even single probands. Although heterogeneous, these genes can be conveniently classified according to the pathway to which they belong. The definition of the molecular and biochemical features of these pathways might be helpful for fundamental knowledge of these disorders, to accelerate genetic diagnosis of patients and the development of rational therapies. In this review, we discuss the molecular findings disclosed in adult patients with muscle pathology hallmarked by mtDNA instability.
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Affiliation(s)
- Naghia Ahmed
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
| | - Dario Ronchi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
| | - Giacomo Pietro Comi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, via Francesco Sforza 35, Milan 20122, Italy.
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111
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Carelli V, Musumeci O, Caporali L, Zanna C, La Morgia C, Del Dotto V, Porcelli AM, Rugolo M, Valentino ML, Iommarini L, Maresca A, Barboni P, Carbonelli M, Trombetta C, Valente EM, Patergnani S, Giorgi C, Pinton P, Rizzo G, Tonon C, Lodi R, Avoni P, Liguori R, Baruzzi A, Toscano A, Zeviani M. Syndromic parkinsonism and dementia associated with OPA1 missense mutations. Ann Neurol 2015; 78:21-38. [PMID: 25820230 PMCID: PMC5008165 DOI: 10.1002/ana.24410] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 01/07/2023]
Abstract
Objective Mounting evidence links neurodegenerative disorders such as Parkinson disease and Alzheimer disease with mitochondrial dysfunction, and recent emphasis has focused on mitochondrial dynamics and quality control. Mitochondrial dynamics and mtDNA maintenance is another link recently emerged, implicating mutations in the mitochondrial fusion genes OPA1 and MFN2 in the pathogenesis of multisystem syndromes characterized by neurodegeneration and accumulation of mtDNA multiple deletions in postmitotic tissues. Here, we report 2 Italian families affected by dominant chronic progressive external ophthalmoplegia (CPEO) complicated by parkinsonism and dementia. Methods Patients were extensively studied by optical coherence tomography (OCT) to assess retinal nerve fibers, and underwent muscle and brain magnetic resonance spectroscopy (MRS), and muscle biopsy and fibroblasts were analyzed. Candidate genes were sequenced, and mtDNA was analyzed for rearrangements. Results Affected individuals displayed a slowly progressive syndrome characterized by CPEO, mitochondrial myopathy, sensorineural deafness, peripheral neuropathy, parkinsonism, and/or cognitive impairment, in most cases without visual complains, but with subclinical loss of retinal nerve fibers at OCT. Muscle biopsies showed cytochrome c oxidase‐negative fibers and mtDNA multiple deletions, and MRS displayed defective oxidative metabolism in muscle and brain. We found 2 heterozygous OPA1 missense mutations affecting highly conserved amino acid positions (p.G488R, p.A495V) in the guanosine triphosphatase domain, each segregating with affected individuals. Fibroblast studies showed a reduced amount of OPA1 protein with normal mRNA expression, fragmented mitochondria, impaired bioenergetics, increased autophagy and mitophagy. Interpretation The association of CPEO and parkinsonism/dementia with subclinical optic neuropathy widens the phenotypic spectrum of OPA1 mutations, highlighting the association of defective mitochondrial dynamics, mtDNA multiple deletions, and altered mitophagy with parkinsonism. Ann Neurol 2015;78:21–38
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Affiliation(s)
- Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Olimpia Musumeci
- Department of Neuroscience, University of Messina, Messina, Italy
| | - Leonardo Caporali
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Claudia Zanna
- Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Valentina Del Dotto
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Anna Maria Porcelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Michela Rugolo
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Maria Lucia Valentino
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Alessandra Maresca
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | | | | | | | - Enza Maria Valente
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Foggia, Italy
| | - Simone Patergnani
- Department of Morphology, Surgery, and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Carlotta Giorgi
- Department of Morphology, Surgery, and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery, and Experimental Medicine, University of Ferrara, Ferrara, Italy
| | - Giovanni Rizzo
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Caterina Tonon
- Functional Magnetic Resonance Unit, St Orsola-Malpighi Polyclinic, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Raffaele Lodi
- Functional Magnetic Resonance Unit, St Orsola-Malpighi Polyclinic, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Patrizia Avoni
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Rocco Liguori
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Agostino Baruzzi
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Unit of Neurology, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Antonio Toscano
- Department of Neuroscience, University of Messina, Messina, Italy
| | - Massimo Zeviani
- Mitochondrial Biology Unit, Medical Research Council, Cambridge, United Kingdom
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112
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Liu Y, Wang X, Chen XJ. Misfolding of mutant adenine nucleotide translocase in yeast supports a novel mechanism of Ant1-induced muscle diseases. Mol Biol Cell 2015; 26:1985-94. [PMID: 25833713 PMCID: PMC4472010 DOI: 10.1091/mbc.e15-01-0030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/26/2015] [Indexed: 12/17/2022] Open
Abstract
Missense mutations in membrane proteins cause dominant diseases by unknown mechanisms. Pathogenic mutations in adenine nucleotide translocase 1 affect protein folding and the assembly of multiple protein complexes. The misfolding of one single protein is therefore sufficient to induce proteostatic stress on the membrane. Approximately one-third of proteins in the cell reside in the membrane. Mutations in membrane proteins can induce conformational changes and expose nonnative polar domains/residues to the lipid environment. The molecular effect of the resulting membrane stress is poorly defined. Adenine nucleotide translocase 1 (Ant1) is a mitochondrial inner membrane protein involved in ATP/ADP exchange. Missense mutations in the Ant1 isoform cause autosomal dominant progressive external ophthalmoplegia (adPEO), cardiomyopathy, and myopathy. The mechanism of the Ant1-induced pathologies is highly debated. Here we show that equivalent mutations in the yeast Aac2 protein cause protein misfolding. Misfolded Aac2 drastically affects the assembly and stability of multiple protein complexes in the membrane, which ultimately inhibits cell growth. Despite causing similar proteostatic damages, the adPEO- but not the cardiomyopathy/myopathy-type Aac2 proteins form large aggregates. The data suggest that the Ant1-induced diseases belong to protein misfolding disorders. Protein homeostasis is subtly maintained on the mitochondrial inner membrane and can be derailed by the misfolding of one single protein with or without aggregate formation. This finding could have broad implications for understanding other dominant diseases (e.g., retinitis pigmentosa) caused by missense mutations in membrane proteins.
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Affiliation(s)
- Yaxin Liu
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Xiaowen Wang
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Xin Jie Chen
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
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113
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Two Novel Mutations in the SLC25A4 Gene in a Patient with Mitochondrial Myopathy. JIMD Rep 2015; 22:39-45. [PMID: 25732997 DOI: 10.1007/8904_2015_409] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 12/12/2022] Open
Abstract
In a 28-year-old male with a mild mitochondrial myopathy manifesting as exercise intolerance and early signs of cardiomyopathy without muscle weakness or ophthalmoplegia, we identified two novel mutations in the SLC25A4 gene: c.707G>C in exon 3 (p.(R236P)) and c.116_137del in exon 2 (p.(Q39Lfs*14)). Serum lactate levels at rest were elevated (12.7 mM). Both the patient's father and brother were heterozygous carriers of the c.707G>C mutation and were asymptomatic. The second mutation causes a 22 bp deletion leading to a frame shift likely giving rise to a premature stop codon and nonsense-mediated decay (NMD). The segregation of the mutations could not be tested directly as the mother had died before. However, indirect evidence from NMD experiments showed that the two mutations were situated on two different alleles in the patient. This case is unique compared to other previously reported patients with either progressive external ophthalmoplegia (PEO) or clear hypertrophic cardiomyopathy with exercise intolerance and/or muscle weakness carrying recessive mutations leading to a complete absence of the SLC25A4 protein. Most likely in our patient, although severely reduced, SLC25A4 is still partially present and functional.
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114
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Iommarini L, Peralta S, Torraco A, Diaz F. Mitochondrial Diseases Part II: Mouse models of OXPHOS deficiencies caused by defects in regulatory factors and other components required for mitochondrial function. Mitochondrion 2015; 22:96-118. [PMID: 25640959 DOI: 10.1016/j.mito.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are defined as defects that affect the oxidative phosphorylation system (OXPHOS). They are characterized by a heterogeneous array of clinical presentations due in part to a wide variety of factors required for proper function of the components of the OXPHOS system. There is no cure for these disorders owing to our poor knowledge of the pathogenic mechanisms of disease. To understand the mechanisms of human disease numerous mouse models have been developed in recent years. Here we summarize the features of several mouse models of mitochondrial diseases directly related to those factors affecting mtDNA maintenance, replication, transcription, translation as well as other proteins that are involved in mitochondrial dynamics and quality control which affect mitochondrial OXPHOS function without being intrinsic components of the system. We discuss how these models have contributed to our understanding of mitochondrial diseases and their pathogenic mechanisms.
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Affiliation(s)
- Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40128 Bologna, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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115
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The ADP/ATP carrier and its relationship to oxidative phosphorylation in ancestral protist trypanosoma brucei. EUKARYOTIC CELL 2015; 14:297-310. [PMID: 25616281 DOI: 10.1128/ec.00238-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The highly conserved ADP/ATP carrier (AAC) is a key energetic link between the mitochondrial (mt) and cytosolic compartments of all aerobic eukaryotic cells, as it exchanges the ATP generated inside the organelle for the cytosolic ADP. Trypanosoma brucei, a parasitic protist of medical and veterinary importance, possesses a single functional AAC protein (TbAAC) that is related to the human and yeast ADP/ATP carriers. However, unlike previous studies performed with these model organisms, this study showed that TbAAC is most likely not a stable component of either the respiratory supercomplex III+IV or the ATP synthasome but rather functions as a physically separate entity in this highly diverged eukaryote. Therefore, TbAAC RNA interference (RNAi) ablation in the insect stage of T. brucei does not impair the activity or arrangement of the respiratory chain complexes. Nevertheless, RNAi silencing of TbAAC caused a severe growth defect that coincides with a significant reduction of mt ATP synthesis by both substrate and oxidative phosphorylation. Furthermore, TbAAC downregulation resulted in a decreased level of cytosolic ATP, a higher mt membrane potential, an elevated amount of reactive oxygen species, and a reduced consumption of oxygen in the mitochondria. Interestingly, while TbAAC has previously been demonstrated to serve as the sole ADP/ATP carrier for ADP influx into the mitochondria, our data suggest that a second carrier for ATP influx may be present and active in the T. brucei mitochondrion. Overall, this study provides more insight into the delicate balance of the functional relationship between TbAAC and the oxidative phosphorylation (OXPHOS) pathway in an early diverged eukaryote.
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116
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Carroll CJ, Brilhante V, Suomalainen A. Next-generation sequencing for mitochondrial disorders. Br J Pharmacol 2014; 171:1837-53. [PMID: 24138576 DOI: 10.1111/bph.12469] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 10/03/2013] [Accepted: 10/13/2013] [Indexed: 12/30/2022] Open
Abstract
A great deal of our understanding of mitochondrial function has come from studies of inherited mitochondrial diseases, but still majority of the patients lack molecular diagnosis. Furthermore, effective treatments for mitochondrial disorders do not exist. Development of therapies has been complicated by the fact that the diseases are extremely heterogeneous, and collecting large enough cohorts of similarly affected individuals to assess new therapies properly has been difficult. Next-generation sequencing technologies have in the last few years been shown to be an effective method for the genetic diagnosis of inherited mitochondrial diseases. Here we review the strategies and findings from studies applying next-generation sequencing methods for the genetic diagnosis of mitochondrial disorders. Detailed knowledge of molecular causes also enables collection of homogenous cohorts of patients for therapy trials, and therefore boosts development of intervention.
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Affiliation(s)
- C J Carroll
- Research Programs Unit, Molecular Neurology, Biomedicum-Helsinki, University of Helsinki, Helsinki, Finland
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117
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Zierz CM, Joshi PR, Zierz S. Frequencies of myohistological mitochondrial changes in patients with mitochondrial DNA deletions and the common m.3243A>G point mutation. Neuropathology 2014; 35:130-6. [DOI: 10.1111/neup.12173] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 09/10/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Charlotte Maria Zierz
- Department of Neurology; Martin-Luther-University, Halle-Wittenberg; Halle/Saale Germany
| | - Pushpa Raj Joshi
- Department of Neurology; Martin-Luther-University, Halle-Wittenberg; Halle/Saale Germany
| | - Stephan Zierz
- Department of Neurology; Martin-Luther-University, Halle-Wittenberg; Halle/Saale Germany
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118
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Palmieri F. Mitochondrial transporters of the SLC25 family and associated diseases: a review. J Inherit Metab Dis 2014; 37:565-75. [PMID: 24797559 DOI: 10.1007/s10545-014-9708-5] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/11/2014] [Accepted: 03/13/2014] [Indexed: 11/25/2022]
Abstract
To date, 14 inherited diseases (including phenotypes) associated to mitochondrial transporters of the SLC25 family have been well characterized biochemically and genetically. They are rare metabolic disorders caused by mutations in the SLC25 nuclear genes that encode mitochondrial carriers, a superfamily of 53 proteins in humans that shuttle a variety of solutes across the mitochondrial membrane. Mitochondrial carriers vary considerably in the nature and size of the substrates they transport, the modes of transport and driving forces. However, their substrate translocation mechanism at the molecular level is thought to be basically the same. Herein, the main structural and functional properties of the SLC25 mitochondrial carriers and the known carrier-related diseases are presented. Two of these disorders, ADP/ATP carrier deficiency and phosphate carrier deficiency, are caused by defects of the two mitochondrial carriers that provide mitochondria with ADP and phosphate, the substrates of oxidative phosphorylation; these disorders therefore are characterized by defective energy production by mitochondria. The mutations of SLC25 carrier genes involved in other cellular functions cause carnitine/acylcarnitine carrier deficiency, HHH syndrome, aspartate/glutamate isoform 1 and 2 deficiencies, congenital Amish microcephaly, neuropathy with bilateral striatal necrosis, congenital sideroblastic anemia, neonatal epileptic encephalopathy, and citrate carrier deficiency; these disorders are characterized by specific metabolic dysfunctions depending on the role of the defective carrier in intermediary metabolism.
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Affiliation(s)
- Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, Laboratory of Biochemistry and Molecular Biology, University of Bari "A. Moro", via E. Orabona, 4, 70125, Bari, Italy,
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119
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Nicholls TJ, Zsurka G, Peeva V, Schöler S, Szczesny RJ, Cysewski D, Reyes A, Kornblum C, Sciacco M, Moggio M, Dziembowski A, Kunz WS, Minczuk M. Linear mtDNA fragments and unusual mtDNA rearrangements associated with pathological deficiency of MGME1 exonuclease. Hum Mol Genet 2014; 23:6147-62. [PMID: 24986917 PMCID: PMC4222359 DOI: 10.1093/hmg/ddu336] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
MGME1, also known as Ddk1 or C20orf72, is a mitochondrial exonuclease found to be involved in the processing of mitochondrial DNA (mtDNA) during replication. Here, we present detailed insights on the role of MGME1 in mtDNA maintenance. Upon loss of MGME1, elongated 7S DNA species accumulate owing to incomplete processing of 5′ ends. Moreover, an 11-kb linear mtDNA fragment spanning the entire major arc of the mitochondrial genome is generated. In contrast to control cells, where linear mtDNA molecules are detectable only after nuclease S1 treatment, the 11-kb fragment persists in MGME1-deficient cells. In parallel, we observed characteristic mtDNA duplications in the absence of MGME1. The fact that the breakpoints of these mtDNA rearrangements do not correspond to either classical deletions or the ends of the linear 11-kb fragment points to a role of MGME1 in processing mtDNA ends, possibly enabling their repair by homologous recombination. In agreement with its functional involvement in mtDNA maintenance, we show that MGME1 interacts with the mitochondrial replicase PolgA, suggesting that it is a constituent of the mitochondrial replisome, to which it provides an additional exonuclease activity. Thus, our results support the viewpoint that MGME1-mediated mtDNA processing is essential for faithful mitochondrial genome replication and might be required for intramolecular recombination of mtDNA.
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Affiliation(s)
| | - Gábor Zsurka
- Department of Epileptology, Life and Brain Center and
| | | | | | - Roman J Szczesny
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland and
| | - Dominik Cysewski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland and
| | - Aurelio Reyes
- Mitochondrial Biology Unit, Medical Research Council, Cambridge, UK
| | - Cornelia Kornblum
- Department of Neurology, University of Bonn Medical Center, Bonn, Germany
| | - Monica Sciacco
- Neuromuscular Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Dino Ferrari, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Centro Dino Ferrari, University of Milan, Milan, Italy
| | - Andrzej Dziembowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland and
| | | | - Michal Minczuk
- Mitochondrial Biology Unit, Medical Research Council, Cambridge, UK,
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120
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Vartiainen S, Chen S, George J, Tuomela T, Luoto KR, O'Dell KMC, Jacobs HT. Phenotypic rescue of a Drosophila model of mitochondrial ANT1 disease. Dis Model Mech 2014; 7:635-48. [PMID: 24812436 PMCID: PMC4036471 DOI: 10.1242/dmm.016527] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A point mutation in the Drosophila gene that codes for the major adult isoform of adenine nuclear translocase (ANT) represents a model for human diseases that are associated with ANT insufficiency [stress-sensitive B1 (sesB1)]. We characterized the organismal, bioenergetic and molecular phenotype of sesB1 flies then tested strategies to compensate the mutant phenotype. In addition to developmental delay and mechanical-stress-induced seizures, sesB1 flies have an impaired response to sound, defective male courtship, female sterility and curtailed lifespan. These phenotypes, excluding the latter two, are shared with the mitoribosomal protein S12 mutant, tko25t. Mitochondria from sesB1 adults showed a decreased respiratory control ratio and downregulation of cytochrome oxidase. sesB1 adults exhibited ATP depletion, lactate accumulation and changes in gene expression that were consistent with a metabolic shift towards glycolysis, characterized by activation of lactate dehydrogenase and anaplerotic pathways. Females also showed downregulation of many genes that are required for oogenesis, and their eggs, although fertilized, failed to develop to the larval stages. The sesB1 phenotypes of developmental delay and mechanical-stress-induced seizures were alleviated by an altered mitochondrial DNA background. Female sterility was substantially rescued by somatic expression of alternative oxidase (AOX) from the sea squirt Ciona intestinalis, whereas AOX did not alleviate developmental delay. Our findings illustrate the potential of different therapeutic strategies for ANT-linked diseases, based on alleviating metabolic stress.
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Affiliation(s)
- Suvi Vartiainen
- BioMediTech and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Shanjun Chen
- BioMediTech and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Jack George
- BioMediTech and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Tea Tuomela
- BioMediTech and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Kaisa R Luoto
- BioMediTech and Tampere University Hospital, FI-33014 University of Tampere, Finland
| | - Kevin M C O'Dell
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - Howard T Jacobs
- BioMediTech and Tampere University Hospital, FI-33014 University of Tampere, Finland. Research Program of Molecular Neurology, FI-00014 University of Helsinki, Finland.
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121
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Mutlu N, Garipler G, Akdoğan E, Dunn CD. Activation of the pleiotropic drug resistance pathway can promote mitochondrial DNA retention by fusion-defective mitochondria in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2014; 4:1247-58. [PMID: 24807265 PMCID: PMC4455774 DOI: 10.1534/g3.114.010330] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Accepted: 05/05/2014] [Indexed: 11/18/2022]
Abstract
Genetic and microscopic approaches using Saccharomyces cerevisiae have identified many proteins that play a role in mitochondrial dynamics, but it is possible that other proteins and pathways that play a role in mitochondrial division and fusion remain to be discovered. Mutants lacking mitochondrial fusion are characterized by rapid loss of mitochondrial DNA. We took advantage of a petite-negative mutant that is unable to survive mitochondrial DNA loss to select for mutations that allow cells with fusion-deficient mitochondria to maintain the mitochondrial genome on fermentable medium. Next-generation sequencing revealed that all identified suppressor mutations not associated with known mitochondrial division components were localized to PDR1 or PDR3, which encode transcription factors promoting drug resistance. Further studies revealed that at least one, if not all, of these suppressor mutations dominantly increases resistance to known substrates of the pleiotropic drug resistance pathway. Interestingly, hyperactivation of this pathway did not significantly affect mitochondrial shape, suggesting that mitochondrial division was not greatly affected. Our results reveal an intriguing genetic connection between pleiotropic drug resistance and mitochondrial dynamics.
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Affiliation(s)
- Nebibe Mutlu
- Department of Molecular Biology and Genetic, Koç University, Sarıyer, İstanbul, 34450, Turkey
| | - Görkem Garipler
- Department of Molecular Biology and Genetic, Koç University, Sarıyer, İstanbul, 34450, Turkey
| | - Emel Akdoğan
- Department of Molecular Biology and Genetic, Koç University, Sarıyer, İstanbul, 34450, Turkey
| | - Cory D Dunn
- Department of Molecular Biology and Genetic, Koç University, Sarıyer, İstanbul, 34450, Turkey
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122
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Chaussenot A, Paquis-Flucklinger V. An overview of neurological and neuromuscular signs in mitochondrial diseases. Rev Neurol (Paris) 2014; 170:323-38. [DOI: 10.1016/j.neurol.2014.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 03/24/2014] [Indexed: 01/10/2023]
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123
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Genetics of mitochondrial respiratory chain deficiencies. Rev Neurol (Paris) 2014; 170:309-22. [DOI: 10.1016/j.neurol.2013.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/27/2013] [Indexed: 01/21/2023]
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124
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Tanaka K, Tateishi T, Kawamura N, Ohyagi Y, Urata M, Kira JI. [A case of sensory ataxic neuropathy, dysarthria, and ophthalmoparesis with multiple mitochondrial DNA deletions]. Rinsho Shinkeigaku 2014; 53:205-11. [PMID: 23524600 DOI: 10.5692/clinicalneurol.53.205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report the case of a 62-year-old man with sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO). He developed gait disturbance at 54 years of age, muscle weakness at 56 years, and difficulty hearing at 58 years. His brother had muscle weakness in both legs from age 20 years, and was diagnosed with Charcot-Marie-Tooth disease because he had muscle weakness of the four extremities, decreased CMAP and SNAP amplitudes on peripheral nerve conduction tests, and loss of large myelinated fibers and onion-bulb formations on sural nerve biopsy. His brother died aged 46 years, but no accurate cause of death was identified. Neurological examination of the present patient revealed bilateral ptosis, external ophthalmoparesis, dysarthria, dysphagia, sensorineural hearing loss, mild weakness and atrophy of proximal muscles in all four limbs, severe sensory ataxia, and disturbance of deep sensation in his legs. He showed elevation of lactate and pyruvate levels in cerebrospinal fluid and serum. An aerobic exercise test disclosed a marked increase in lactate and pyruvate levels in serum. On nerve conduction study, amplitudes of CMAP and SNAP, and F wave-evoked frequency were decreased. Needle electromyography showed chronic neurogenic patterns with fibrillation potentials in the extremity muscles. Head MRI demonstrated T2 prolonged lesions in the bilateral basal ganglia, while brain MRS revealed a small lactate peak. Biopsy of his left lateral vastus muscle showed ragged-red fibers and group atrophy, and some muscle fibers had decreased cytochrome c activity. Left sural nerve biopsy revealed a marked loss of large myelinated fibers, and some onion-bulb formations. Genetic testing disclosed a large mtDNA deletion in the biopsied muscle. Among nuclear genes, we found point mutations in ANT-1 (exon 1 c.105G>A, 5' untranslated region) and POLG-1 (exon 4, c.1218G>A, p. and exon 23 c.3920C>T, p.A1217V). We diagnosed SANDO. This is the first case of SANDO with large mitochondrial DNA deletions in Japanese.
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Affiliation(s)
- Koji Tanaka
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University
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125
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Wedding IM, Koht J, Tran GT, Misceo D, Selmer KK, Holmgren A, Frengen E, Bindoff L, Tallaksen CME, Tzoulis C. Spastic paraplegia type 7 is associated with multiple mitochondrial DNA deletions. PLoS One 2014; 9:e86340. [PMID: 24466038 PMCID: PMC3899233 DOI: 10.1371/journal.pone.0086340] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 12/11/2013] [Indexed: 11/19/2022] Open
Abstract
Spastic paraplegia 7 is an autosomal recessive disorder caused by mutations in the gene encoding paraplegin, a protein located at the inner mitochondrial membrane and involved in the processing of other mitochondrial proteins. The mechanism whereby paraplegin mutations cause disease is unknown. We studied two female and two male adult patients from two Norwegian families with a combination of progressive external ophthalmoplegia and spastic paraplegia. Sequencing of SPG7 revealed a novel missense mutation, c.2102A>C, p.H 701P, which was homozygous in one family and compound heterozygous in trans with a known pathogenic mutation c.1454_1462del in the other. Muscle was examined from an additional, unrelated adult female patient with a similar phenotype caused by a homozygous c.1047insC mutation in SPG7. Immunohistochemical studies in skeletal muscle showed mosaic deficiency predominantly affecting respiratory complex I, but also complexes III and IV. Molecular studies in single, microdissected fibres showed multiple mitochondrial DNA deletions segregating at high levels (38-97%) in respiratory deficient fibres. Our findings demonstrate for the first time that paraplegin mutations cause accumulation of mitochondrial DNA damage and multiple respiratory chain deficiencies. While paraplegin is not known to be directly associated with the mitochondrial nucleoid, it is known to process other mitochondrial proteins and it is possible therefore that paraplegin mutations lead to mitochondrial DNA deletions by impairing proteins involved in the homeostasis of the mitochondrial genome. These studies increase our understanding of the molecular pathogenesis of SPG7 mutations and suggest that SPG7 testing should be included in the diagnostic workup of autosomal recessive, progressive external ophthalmoplegia, especially if spasticity is present.
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Affiliation(s)
- Iselin Marie Wedding
- Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway
- University of Oslo, Faculty of Medicine, Oslo, Norway
| | - Jeanette Koht
- University of Oslo, Faculty of Medicine, Oslo, Norway
- Department of Neurology, Drammen Hospital, Vestre Viken Health Trust, Norway
| | - Gia Tuong Tran
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Doriana Misceo
- University of Oslo, Faculty of Medicine, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Kaja Kristine Selmer
- University of Oslo, Faculty of Medicine, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Asbjørn Holmgren
- University of Oslo, Faculty of Medicine, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Eirik Frengen
- University of Oslo, Faculty of Medicine, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Laurence Bindoff
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Chantal M. E. Tallaksen
- Department of Neurology, Oslo University Hospital, Ullevål, Oslo, Norway
- University of Oslo, Faculty of Medicine, Oslo, Norway
| | - Charalampos Tzoulis
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
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Siciliano G, Pasquali L, Mancuso M, Murri L. Molecular diagnostics and mitochondrial dysfunction: a future perspective. Expert Rev Mol Diagn 2014; 8:531-49. [DOI: 10.1586/14737159.8.4.531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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127
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Ohnuki Y, Takahashi K, Iijima E, Takahashi W, Suzuki S, Ozaki Y, Kitao R, Mihara M, Ishihara T, Nakamura M, Sawano Y, Goto YI, Izumi S, Kulski JK, Shiina T, Takizawa S. Multiple deletions in mitochondrial DNA in a patient with progressive external ophthalmoplegia, leukoencephalopathy and hypogonadism. Intern Med 2014; 53:1365-9. [PMID: 24930659 DOI: 10.2169/internalmedicine.53.1320] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Progressive external ophthalmoplegia (PEO) is one of a number of major types of mitochondrial disorders. Most sporadic PEO patients have a heteroplasmic large deletion of mitochondrial DNA (mtDNA) in the mitochondria in skeletal muscles. We herein analyzed mtDNA deletions using sub-cloning and Sanger sequencing of PCR products in a 31-year-old Japanese man with multiple symptoms, including PEO, muscle weakness, hearing loss, leukoencephalopathy and hypogonadism. A large number of multiple deletions was detected, as well as four kinds of deletion breakpoints identified in different locations, including m.3347_12322, m.5818_13964, m.5829_13964 and m.5837_13503.
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Affiliation(s)
- Yuko Ohnuki
- Department of Molecular Life Science, Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, Japan
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Paradas C, Camaño P, Otaegui D, Oz O, Emmanuele V, DiMauro S, Hirano M. Longitudinal clinical follow-up of a large family with the R357P Twinkle mutation. JAMA Neurol 2013; 70:1425-8. [PMID: 24018892 DOI: 10.1001/jamaneurol.2013.3185] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Autosomal dominant progressive external ophthalmoplegia due to PEO1 mutations is considered relatively benign, but no data about long-term progression of this disease have been reported. The aim of this study was to provide a 16-year clinical follow-up of autosomal dominant progressive external ophthalmoplegia due to the p.R357P gene mutation in PEO1. OBSERVATIONS Twenty-two members of an Irish-American family were examined in 1996, when PEO1 sequencing revealed a c.1071G>C/p.R357P mutation in 9 of them. We reexamined the family in 2012 using a standardized clinical protocol. Autosomal dominant progressive external ophthalmoplegia due to the p.R357P PEO1 mutation is a late-onset ocular myopathy beginning with ptosis and progressing slowly. Ophthalmoparesis, if present, is mild and evident only by neurological examination. CONCLUSIONS AND RELEVANCE Our results are important for prognosis and genetic counseling.
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Affiliation(s)
- Carmen Paradas
- Unidad de Enfermedades Neuromusculares, Servicio de Neurología, Hospital Universitario Virgen del Rocío/Instituto de Biomedicina de Sevilla/Consejo Superior de Investigaciones Científicas/Universidad de Sevilla, Seville, Spain2Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III, Ministry of Economy and Competitiveness, Madrid, Spain3Department of Neurology, Columbia University Medical Center, New York, New York
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Zapico SC, Ubelaker DH. mtDNA Mutations and Their Role in Aging, Diseases and Forensic Sciences. Aging Dis 2013; 4:364-80. [PMID: 24307969 DOI: 10.14336/ad.2013.0400364] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/02/2013] [Accepted: 10/02/2013] [Indexed: 12/28/2022] Open
Abstract
Mitochondria are independent organelles with their own DNA. As a primary function, mitochondria produce the energy for the cell through Oxidative Phosphorylation (OXPHOS) in the Electron Transport Chain (ETC). One of the toxic products of this process is Reactive Oxygen Species (ROS), which can induce oxidative damage in macromolecules like lipids, proteins and DNA. Mitochondrial DNA (mtDNA) is less protected and has fewer reparation mechanisms than nuclear DNA (nDNA), and as such is more exposed to oxidative, mutation-inducing damage. This review analyzes the causes and consequences of mtDNA mutations and their relationship with the aging process. Neurodegenerative diseases, related with the aging, are consequences of mtDNA mutations resulting in a decrease in mitochondrial function. Also described are "mitochondrial diseases", pathologies produced by mtDNA mutations and whose symptoms are related with mitochondrial dysfunction. Finally, mtDNA haplogroups are defined in this review; these groups are important for determination of geographical origin of an individual. Additionally, different haplogroups exhibit variably longevity and risk of certain diseases. mtDNA mutations in aging and haplogroups are of special interest to forensic science research. Therefore this review will help to clarify the key role of mtDNA mutations in these processes and support further research in this area.
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Affiliation(s)
- Sara C Zapico
- Smithsonian Institution, National Museum of Natural History, Department of Anthropology, Washington, DC 20560, USA
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130
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Cámara Y, González-Vioque E, Scarpelli M, Torres-Torronteras J, Martí R. Feeding the deoxyribonucleoside salvage pathway to rescue mitochondrial DNA. Drug Discov Today 2013; 18:950-7. [DOI: 10.1016/j.drudis.2013.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/27/2013] [Accepted: 06/19/2013] [Indexed: 12/16/2022]
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Clémençon B, Babot M, Trézéguet V. The mitochondrial ADP/ATP carrier (SLC25 family): pathological implications of its dysfunction. Mol Aspects Med 2013; 34:485-93. [PMID: 23506884 DOI: 10.1016/j.mam.2012.05.006] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 02/10/2012] [Indexed: 02/04/2023]
Abstract
In aerobic eukaryotic cells, the high energy metabolite ATP is generated mainly within the mitochondria following the process of oxidative phosphorylation. The mitochondrial ATP is exported to the cytoplasm using a specialized transport protein, the ADP/ATP carrier, to provide energy to the cell. Any deficiency or dysfunction of this membrane protein leads to serious consequences on cell metabolism and can cause various diseases such as muscular dystrophy. Described as a decisive player in the programmed cell death, it was recently shown to play a role in cancer. The objective of this review is to summarize the current knowledge of the involvement of the ADP/ATP carrier, encoded by the SLC25A4, SLC25A5, SLC25A6 and SLC25A31 genes, in human diseases and of the efforts made at designing different model systems to study this carrier and the associated pathologies through biochemical, genetic, and structural approaches.
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Affiliation(s)
- Benjamin Clémençon
- Institute of Biochemistry and Molecular Medicine, NCCR TransCure, University of Bern, Bern, Switzerland.
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132
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Milone M, Wong LJ. Diagnosis of mitochondrial myopathies. Mol Genet Metab 2013; 110:35-41. [PMID: 23911206 DOI: 10.1016/j.ymgme.2013.07.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 07/10/2013] [Accepted: 07/10/2013] [Indexed: 01/01/2023]
Abstract
Mitochondria are ubiquitous organelles and play crucial roles in vital functions, most importantly, the oxidative phosphorylation and energy metabolism. Therefore, mitochondrial dysfunction can affect multiple tissues, with muscle and nerve preferentially affected. Mitochondrial myopathy is a common clinical phenotype, which is characterized by early fatigue and/or fixed muscle weakness; rhabdomyolysis can seldom occur. Muscle biopsy often identifies signs of diseased mitochondria by morphological studies, while biochemical analysis may identify respiratory chain deficiencies. The clinical, morphological and biochemical data guide molecular analysis. Being the mitochondrial function under the control of both mitochondrial DNA and nuclear DNA, the search for mitochondrial DNA mutations and mitochondrial DNA quantitation, may not be sufficient for the molecular diagnosis of mitochondrial myopathies. Approximately 1500 nuclear genes can affect mitochondrial structure and function and the targeting of such genes may be necessary to reach the diagnosis. The identification of causative molecular defects in nuclear or mitochondrial genome leads to the definite diagnosis of mitochondrial myopathy.
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Affiliation(s)
- Margherita Milone
- Department of Neurology, Neuromuscular Division, Mayo Clinic, Rochester, MN, USA
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133
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134
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Dolhun R, Presant EM, Hedera P. Novel polymerase gamma (POLG1) gene mutation in the linker domain associated with parkinsonism. BMC Neurol 2013; 13:92. [PMID: 23865558 PMCID: PMC3728152 DOI: 10.1186/1471-2377-13-92] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 07/11/2013] [Indexed: 11/18/2022] Open
Abstract
Background Mutations in the POLG1 gene have variable phenotypic presentations and a high degree of clinical suspicion is necessary for their recognition. Parkinsonism and ataxia are the most common movement disorders associated with POLG1 mutations but no phenotype-genotype correlation has been established. Case presentation We identified a male patient with progressive external ophthalmoplegia who also developed a progressive bradykinesia, rigidity and camptocormia in the third decade. Parkinsonism was partially responsive to dopaminegic replacement. His father and brother had reportedly similar clinical problems. Genetic analysis identified a novel mutation p.K512M in the POLG1 gene. Conclusion This report further expands the spectrum of POLG1-associated neurologic problems with the report of a novel mutation in the linker region of the gene, which are rarely associated with parkinsonism.
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Affiliation(s)
- Rachel Dolhun
- Department of Neurology, Vanderbilt University, 465 21st Avenue South, 6140 MRB III, Nashville, TN, USA
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135
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Adenine nucleotide translocase, mitochondrial stress, and degenerative cell death. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:146860. [PMID: 23970947 PMCID: PMC3732615 DOI: 10.1155/2013/146860] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 06/14/2013] [Accepted: 06/24/2013] [Indexed: 12/18/2022]
Abstract
Mitochondria are intracellular organelles involved in ATP synthesis, apoptosis, calcium signaling, metabolism, and the synthesis of critical metabolic cofactors. Mitochondrial dysfunction is associated with age-related degenerative diseases. How mitochondrial dysfunction causes cell degeneration is not well understood. Recent studies have shown that mutations in the adenine nucleotide translocase (Ant) cause aging-dependent degenerative cell death (DCD) in yeast, which is sequentially manifested by inner membrane stress, mitochondrial DNA (mtDNA) loss, and progressive loss of cell viability. Ant is an abundant protein primarily involved in ADP/ATP exchange across the mitochondrial inner membrane. It also mediates basal proton leak and regulates the mitochondrial permeability transition pore. Missense mutations in the human Ant1 cause several degenerative diseases which are commonly manifested by fractional mtDNA deletions. Multiple models have been proposed to explain the Ant1-induced pathogenesis. Studies from yeast have suggested that in addition to altered nucleotide transport properties, the mutant proteins cause a global stress on the inner membrane. The mutant proteins likely interfere with general mitochondrial biogenesis in a dominant-negative manner, which secondarily destabilizes mtDNA. More recent work revealed that the Ant-induced DCD is suppressed by reduced cytosolic protein synthesis. This finding suggests a proteostatic crosstalk between mitochondria and the cytosol, which may play an important role for cell survival during aging.
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136
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Affiliation(s)
- Jin-Hong Shin
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Dae-Seong Kim
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
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137
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Abstract
The classical Mendelian genetic perspective has failed to adequately explain the biology and genetics of common metabolic and degenerative diseases. This is because these diseases are primarily systemic bioenergetic diseases, and the most important energy genes are located in the cytoplasmic mitochondrial DNA (mtDNA). Therefore, to understand these "complex" diseases, we must investigate their bioenergetic pathophysiology and consider the genetics of the thousands of copies of maternally inherited mtDNA, the more than 1,000 nuclear DNA (nDNA) bioenergetic genes, and the epigenomic and signal transduction systems that coordinate these dispersed elements of the mitochondrial genome.
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Affiliation(s)
- Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia, and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-4302, USA.
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138
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Malki K, Campbell J, Davies M, Keers R, Uher R, Ward M, Paya-Cano J, Aitchinson KJ, Binder E, Sluyter F, Kuhn K, Selzer S, Craig I, McGuffin P, Schalkwyk LC. Pharmacoproteomic investigation into antidepressant response in two mouse inbred strains. Proteomics 2013; 12:2355-65. [PMID: 22696452 DOI: 10.1002/pmic.201100306] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this study, we present a pharmacoproteomic investigation of response to antidepressants two inbred strains. Our aim was to uncover molecular mechanisms underlying antidepressant action and identify new biomarkers to determine therapeutic response to two antidepressants with proven efficacy in the treatment of depression but divergent mechanisms of action. Mice were treated with the pro-noradrenergic drug nortriptyline, the pro-serotonergic drug escitalopram or saline. Quantitative proteomic analyses were undertaken on hippocampal tissue from a study design that used two inbred mouse strains, two depressogenic protocols and a control condition, (maternal separation, chronic mild stress, control), two antidepressant drugs and two dosing protocols. The proteomic analysis was aimed at the identification of specific drug-response markers. Complementary approaches, 2DE and isobaric tandem mass tagging (TMT), were applied to the selected experimental groups. To investigate the relationship between proteomic profiles, depressogenic protocols and drug response, 2DE and TMT data sets were analysed using multivariate methods. The results highlighted significant strain- and stress-related differences across both 2DE and TMT data sets and identified the three gene products involved in serotonergic (PXBD5, YHWAB, SLC25A4) and one in noradrenergic antidepressant action (PXBD6).
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Affiliation(s)
- Karim Malki
- King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, London, UK.
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139
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Strauss KA, DuBiner L, Simon M, Zaragoza M, Sengupta PP, Li P, Narula N, Dreike S, Platt J, Procaccio V, Ortiz-González XR, Puffenberger EG, Kelley RI, Morton DH, Narula J, Wallace DC. Severity of cardiomyopathy associated with adenine nucleotide translocator-1 deficiency correlates with mtDNA haplogroup. Proc Natl Acad Sci U S A 2013; 110:3453-8. [PMID: 23401503 PMCID: PMC3587196 DOI: 10.1073/pnas.1300690110] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mutations of both nuclear and mitochondrial DNA (mtDNA)-encoded mitochondrial proteins can cause cardiomyopathy associated with mitochondrial dysfunction. Hence, the cardiac phenotype of nuclear DNA mitochondrial mutations might be modulated by mtDNA variation. We studied a 13-generation Mennonite pedigree with autosomal recessive myopathy and cardiomyopathy due to an SLC25A4 frameshift null mutation (c.523delC, p.Q175RfsX38), which codes for the heart-muscle isoform of the adenine nucleotide translocator-1. Ten homozygous null (adenine nucleotide translocator-1(-/-)) patients monitored over a median of 6 years had a phenotype of progressive myocardial thickening, hyperalaninemia, lactic acidosis, exercise intolerance, and persistent adrenergic activation. Electrocardiography and echocardiography with velocity vector imaging revealed abnormal contractile mechanics, myocardial repolarization abnormalities, and impaired left ventricular relaxation. End-stage heart disease was characterized by massive, symmetric, concentric cardiac hypertrophy; widespread cardiomyocyte degeneration; overabundant and structurally abnormal mitochondria; extensive subendocardial interstitial fibrosis; and marked hypertrophy of arteriolar smooth muscle. Substantial variability in the progression and severity of heart disease segregated with maternal lineage, and sequencing of mtDNA from five maternal lineages revealed two major European haplogroups, U and H. Patients with the haplogroup U mtDNAs had more rapid and severe cardiomyopathy than those with haplogroup H.
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Affiliation(s)
- Kevin A. Strauss
- Clinic for Special Children, Strasburg, PA 17579
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17603
- Lancaster General Hospital, Lancaster, PA 17602
| | - Lauren DuBiner
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17603
| | - Mariella Simon
- Departments of Pediatrics and Biological Chemistry and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, CA 92697
| | - Michael Zaragoza
- Departments of Pediatrics and Biological Chemistry and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, CA 92697
| | | | - Peng Li
- Department of Medicine, University of California, Irvine, CA 92697
| | - Navneet Narula
- Department of Pathology, Weill Cornell Medical College, New York, NY 10019
| | - Sandra Dreike
- Departments of Pediatrics and Biological Chemistry and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, CA 92697
- Kapiolani Medical Center for Women and Children, Honolulu, HI 96826
| | - Julia Platt
- Departments of Pediatrics and Biological Chemistry and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, CA 92697
- Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA 94305
| | - Vincent Procaccio
- Departments of Pediatrics and Biological Chemistry and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, CA 92697
- Biochemistry and Genetics Department, National Center for Neurodegenerative and Mitochondrial Diseases, Centre Hospitalier Universitaire d' Angers, 49933 Angers, France
| | - Xilma R. Ortiz-González
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Erik G. Puffenberger
- Clinic for Special Children, Strasburg, PA 17579
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17603
| | - Richard I. Kelley
- Kennedy Krieger Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - D. Holmes Morton
- Clinic for Special Children, Strasburg, PA 17579
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17603
- Lancaster General Hospital, Lancaster, PA 17602
| | | | - Douglas C. Wallace
- Departments of Pediatrics and Biological Chemistry and Center for Molecular and Mitochondrial Medicine and Genetics, University of California, Irvine, CA 92697
- Center for Mitochondrial and Epigenomic Medicine, Children’s Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
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140
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Early-onset ataxia with progressive external ophthalmoplegia associated with POLG mutation: autosomal recessive mitochondrial ataxic syndrome or SANDO? Neurologist 2013; 18:287-9. [PMID: 22931735 DOI: 10.1097/nrl.0b013e318266f5a6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Autosomal recessive ataxias caused by mutations of the polymerase γ (POLG) gene make an important group of progressive ataxias accompanied by a diverse spectrum of neurological disorders. Because the clinical picture can be quite miscellaneous, it is challenging to assort patients to any of the currently described syndromes; therefore, to provide such a patient with a conclusive diagnosis can be challenging for the neurologist. A typical magnetic resonance imaging finding is probably the most useful landmark in the diagnostic process, which will steer the clinician toward POLG gene testing. To illustrate this, we present a case of progressive ataxia caused by A467T and W748S mutations of POLG gene, who presented with overlapping symptoms of autosomal recessive mitochondrial ataxic syndrome and SANDO, as well as choreoathetotic movements and dysphonia. After lengthy investigations, magnetic resonance imaging showed T2 and FLAIR hyperintensities in the thalamus, inferior olives, and cerebellum, which led us to the analysis of POLG mutations.
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141
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Krag TO, Hauerslev S, Jeppesen TD, Duno M, Vissing J. Muscle regeneration in mitochondrial myopathies. Mitochondrion 2013; 13:63-70. [PMID: 23376095 DOI: 10.1016/j.mito.2013.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 01/18/2013] [Accepted: 01/24/2013] [Indexed: 10/27/2022]
Abstract
Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected by a dystrophic morphology. The results add to the complexity of the pathogenesis underlying mitochondrial myopathies, and expand the knowledge about the impact of energy deficiency on another aspect of muscle structure and function.
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Affiliation(s)
- T O Krag
- Neuromuscular Research Unit, Department of Neurology, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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142
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Abstract
Mutations in the human mitochondrial genome are known to cause an array of diverse disorders, most of which are maternally inherited, and all of which are associated with defects in oxidative energy metabolism. It is now emerging that somatic mutations in mitochondrial DNA (mtDNA) are also linked to other complex traits, including neurodegenerative diseases, ageing and cancer. Here we discuss insights into the roles of mtDNA mutations in a wide variety of diseases, highlighting the interesting genetic characteristics of the mitochondrial genome and challenges in studying its contribution to pathogenesis.
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143
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Loss-of-function mutations in MGME1 impair mtDNA replication and cause multisystemic mitochondrial disease. Nat Genet 2013; 45:214-9. [PMID: 23313956 DOI: 10.1038/ng.2501] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 11/28/2012] [Indexed: 12/17/2022]
Abstract
Known disease mechanisms in mitochondrial DNA (mtDNA) maintenance disorders alter either the mitochondrial replication machinery (POLG, POLG2 and C10orf2) or the biosynthesis pathways of deoxyribonucleoside 5'-triphosphates for mtDNA synthesis. However, in many of these disorders, the underlying genetic defect has yet to be discovered. Here, we identify homozygous nonsense and missense mutations in the orphan gene C20orf72 in three families with a mitochondrial syndrome characterized by external ophthalmoplegia, emaciation and respiratory failure. Muscle biopsies showed mtDNA depletion and multiple mtDNA deletions. C20orf72, hereafter MGME1 (mitochondrial genome maintenance exonuclease 1), encodes a mitochondrial RecB-type exonuclease belonging to the PD-(D/E)XK nuclease superfamily. We show that MGME1 cleaves single-stranded DNA and processes DNA flap substrates. Fibroblasts from affected individuals do not repopulate after chemically induced mtDNA depletion. They also accumulate intermediates of stalled replication and show increased levels of 7S DNA, as do MGME1-depleted cells. Thus, we show that MGME1-mediated mtDNA processing is essential for mitochondrial genome maintenance.
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144
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Pitceathly RDS, Smith C, Fratter C, Alston CL, He L, Craig K, Blakely EL, Evans JC, Taylor J, Shabbir Z, Deschauer M, Pohl U, Roberts ME, Jackson MC, Halfpenny CA, Turnpenny PD, Lunt PW, Hanna MG, Schaefer AM, McFarland R, Horvath R, Chinnery PF, Turnbull DM, Poulton J, Taylor RW, Gorman GS. Adults with RRM2B-related mitochondrial disease have distinct clinical and molecular characteristics. ACTA ACUST UNITED AC 2012; 135:3392-403. [PMID: 23107649 PMCID: PMC3501970 DOI: 10.1093/brain/aws231] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mutations in the nuclear-encoded mitochondrial maintenance gene RRM2B are an important cause of familial mitochondrial disease in both adults and children and represent the third most common cause of multiple mitochondrial DNA deletions in adults, following POLG [polymerase (DNA directed), gamma] and PEO1 (now called C10ORF2, encoding the Twinkle helicase) mutations. However, the clinico-pathological and molecular features of adults with RRM2B-related disease have not been clearly defined. In this multicentre study of 26 adult patients from 22 independent families, including five additional cases published in the literature, we show that extra-ocular neurological complications are common in adults with genetically confirmed RRM2B mutations. We also demonstrate a clear correlation between the clinical phenotype and the underlying genetic defect. Myopathy was a prominent manifestation, followed by bulbar dysfunction and fatigue. Sensorineural hearing loss and gastrointestinal disturbance were also important findings. Severe multisystem neurological disease was associated with recessively inherited compound heterozygous mutations with a mean age of disease onset at 7 years. Dominantly inherited heterozygous mutations were associated with a milder predominantly myopathic phenotype with a later mean age of disease onset at 46 years. Skeletal muscle biopsies revealed subsarcolemmal accumulation of mitochondria and/or cytochrome c oxidase-deficient fibres. Multiple mitochondrial DNA deletions were universally present in patients who underwent a muscle biopsy. We identified 18 different heterozygous RRM2B mutations within our cohort of patients, including five novel mutations that have not previously been reported. Despite marked clinical overlap between the mitochondrial maintenance genes, key clinical features such as bulbar dysfunction, hearing loss and gastrointestinal disturbance should help prioritize genetic testing towards RRM2B analysis, and sequencing of the gene may preclude performance of a muscle biopsy.
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Affiliation(s)
- Robert D S Pitceathly
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
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145
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Ronchi D, Garone C, Bordoni A, Gutierrez Rios P, Calvo SE, Ripolone M, Ranieri M, Rizzuti M, Villa L, Magri F, Corti S, Bresolin N, Mootha VK, Moggio M, DiMauro S, Comi GP, Sciacco M. Next-generation sequencing reveals DGUOK mutations in adult patients with mitochondrial DNA multiple deletions. Brain 2012; 135:3404-15. [PMID: 23043144 DOI: 10.1093/brain/aws258] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The molecular diagnosis of mitochondrial disorders still remains elusive in a large proportion of patients, but advances in next generation sequencing are significantly improving our chances to detect mutations even in sporadic patients. Syndromes associated with mitochondrial DNA multiple deletions are caused by different molecular defects resulting in a wide spectrum of predominantly adult-onset clinical presentations, ranging from progressive external ophthalmoplegia to multi-systemic disorders of variable severity. The mutations underlying these conditions remain undisclosed in half of the affected subjects. We applied next-generation sequencing of known mitochondrial targets (MitoExome) to probands presenting with adult-onset mitochondrial myopathy and harbouring mitochondrial DNA multiple deletions in skeletal muscle. We identified autosomal recessive mutations in the DGUOK gene (encoding mitochondrial deoxyguanosine kinase), which has previously been associated with an infantile hepatocerebral form of mitochondrial DNA depletion. Mutations in DGUOK occurred in five independent subjects, representing 5.6% of our cohort of patients with mitochondrial DNA multiple deletions, and impaired both muscle DGUOK activity and protein stability. Clinical presentations were variable, including mitochondrial myopathy with or without progressive external ophthalmoplegia, recurrent rhabdomyolysis in a young female who had received a liver transplant at 9 months of age and adult-onset lower motor neuron syndrome with mild cognitive impairment. These findings reinforce the concept that mutations in genes involved in deoxyribonucleotide metabolism can cause diverse clinical phenotypes and suggest that DGUOK should be screened in patients harbouring mitochondrial DNA deletions in skeletal muscle.
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Affiliation(s)
- Dario Ronchi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy.
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Sanchez-Martinez A, Calleja M, Peralta S, Matsushima Y, Hernandez-Sierra R, Whitworth AJ, Kaguni LS, Garesse R. Modeling pathogenic mutations of human twinkle in Drosophila suggests an apoptosis role in response to mitochondrial defects. PLoS One 2012; 7:e43954. [PMID: 22952820 PMCID: PMC3429445 DOI: 10.1371/journal.pone.0043954] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 07/27/2012] [Indexed: 01/31/2023] Open
Abstract
The human gene C10orf2 encodes the mitochondrial replicative DNA helicase Twinkle, mutations of which are responsible for a significant fraction of cases of autosomal dominant progressive external ophthalmoplegia (adPEO), a human mitochondrial disease caused by defects in intergenomic communication. We report the analysis of orthologous mutations in the Drosophila melanogaster mitochondrial DNA (mtDNA) helicase gene, d-mtDNA helicase. Increased expression of wild type d-mtDNA helicase using the UAS-GAL4 system leads to an increase in mtDNA copy number throughout adult life without any noteworthy phenotype, whereas overexpression of d-mtDNA helicase containing the K388A mutation in the helicase active site results in a severe depletion of mtDNA and a lethal phenotype. Overexpression of two d-mtDNA helicase variants equivalent to two human adPEO mutations shows differential effects. The A442P mutation exhibits a dominant negative effect similar to that of the active site mutant. In contrast, overexpression of d-mtDNA helicase containing the W441C mutation results in a slight decrease in mtDNA copy number during the third instar larval stage, and a moderate decrease in life span in the adult population. Overexpression of d-mtDNA helicase containing either the K388A or A442P mutations causes a mitochondrial oxidative phosphorylation (OXPHOS) defect that significantly reduces cell proliferation. The mitochondrial impairment caused by these mutations promotes apoptosis, arguing that mitochondria regulate programmed cell death in Drosophila. Our study of d-mtDNA helicase overexpression provides a tractable Drosophila model for understanding the cellular and molecular effects of human adPEO mutations.
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Affiliation(s)
- Alvaro Sanchez-Martinez
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, and Centro de Investigación Biomédica en Red en Enfermedades Raras, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- Instituto de Investigación Santitaria Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Manuel Calleja
- Centro de Biología Molecular “Severo Ochoa” Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Susana Peralta
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, and Centro de Investigación Biomédica en Red en Enfermedades Raras, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- Instituto de Investigación Santitaria Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Yuichi Matsushima
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Rosana Hernandez-Sierra
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, and Centro de Investigación Biomédica en Red en Enfermedades Raras, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- Instituto de Investigación Santitaria Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Alexander J. Whitworth
- Department of Biomedical Sciences, MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
| | - Laurie S. Kaguni
- Department of Biochemistry and Molecular Biology and Center for Mitochondrial Science and Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Rafael Garesse
- Departamento de Bioquímica, Instituto de Investigaciones Biomédicas “Alberto Sols” Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, and Centro de Investigación Biomédica en Red en Enfermedades Raras, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
- Instituto de Investigación Santitaria Hospital 12 de Octubre (i+12), Madrid, Spain
- * E-mail:
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147
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Dhillon S, Hellings JA, Butler MG. Genetics and mitochondrial abnormalities in autism spectrum disorders: a review. Curr Genomics 2012; 12:322-32. [PMID: 22294875 PMCID: PMC3145262 DOI: 10.2174/138920211796429745] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/24/2011] [Accepted: 05/25/2011] [Indexed: 02/08/2023] Open
Abstract
We review the current status of the role and function of the mitochondrial DNA (mtDNA) in the etiology of autism spectrum disorders (ASD) and the interaction of nuclear and mitochondrial genes. High lactate levels reported in about one in five children with ASD may indicate involvement of the mitochondria in energy metabolism and brain development. Mitochondrial disturbances include depletion, decreased quantity or mutations of mtDNA producing defects in biochemical reactions within the mitochondria. A subset of individuals with ASD manifests copy number variation or small DNA deletions/duplications, but fewer than 20 percent are diagnosed with a single gene condition such as fragile X syndrome. The remaining individuals with ASD have chromosomal abnormalities (e.g., 15q11-q13 duplications), other genetic or multigenic causes or epigenetic defects. Next generation DNA sequencing techniques will enable better characterization of genetic and molecular anomalies in ASD, including defects in the mitochondrial genome particularly in younger children.
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Affiliation(s)
- Sukhbir Dhillon
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, Kansas University Medical Center, Kansas City, Kansas 66160, USA
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148
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Ravaud S, Bidon-Chanal A, Blesneac I, Machillot P, Juillan-Binard C, Dehez F, Chipot C, Pebay-Peyroula E. Impaired transport of nucleotides in a mitochondrial carrier explains severe human genetic diseases. ACS Chem Biol 2012; 7:1164-9. [PMID: 22497660 DOI: 10.1021/cb300012j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mitochondrial ADP/ATP carrier (AAC) is a prominent actor in the energetic regulation of the cell, importing ADP into the mitochondria and exporting ATP toward the cytoplasm. Severe genetic diseases have been ascribed to specific mutations in this membrane protein. How minute, well-localized modifications of the transporter impact the function of the mitochondria remains, however, largely unclear. Here, for the first time, the relationship between all documented pathological mutations of the AAC and its transport properties is established. Activity measurements combined synergistically with molecular-dynamics simulations demonstrate how all documented pathological mutations alter the binding affinity and the translocation kinetics of the nucleotides. Throwing a bridge between the pathologies and their molecular origins, these results reveal two distinct mechanisms responsible for AAC-related genetic disorders, wherein the mutations either modulate the association of the nucleotides to the carrier by modifying its electrostatic signature or reduce its conformational plasticity.
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Affiliation(s)
- Stéphanie Ravaud
- Université
Grenoble 1,
IBS, Institut de Biologie Structurale, 41, rue Jules Horowitz, 38027
Grenoble cedex 1, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Axel Bidon-Chanal
- Nancy Université, BP239,
54506 Vandoeuvre-lès-Nancy Cedex, France
- CNRS, SRSMC, Nancy, France
| | - Iulia Blesneac
- Université
Grenoble 1,
IBS, Institut de Biologie Structurale, 41, rue Jules Horowitz, 38027
Grenoble cedex 1, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Paul Machillot
- Université
Grenoble 1,
IBS, Institut de Biologie Structurale, 41, rue Jules Horowitz, 38027
Grenoble cedex 1, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - Céline Juillan-Binard
- Université
Grenoble 1,
IBS, Institut de Biologie Structurale, 41, rue Jules Horowitz, 38027
Grenoble cedex 1, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
| | - François Dehez
- Nancy Université, BP239,
54506 Vandoeuvre-lès-Nancy Cedex, France
- CNRS, SRSMC, Nancy, France
| | - Chris Chipot
- Nancy Université, BP239,
54506 Vandoeuvre-lès-Nancy Cedex, France
- CNRS, SRSMC, Nancy, France
| | - Eva Pebay-Peyroula
- Université
Grenoble 1,
IBS, Institut de Biologie Structurale, 41, rue Jules Horowitz, 38027
Grenoble cedex 1, France
- CEA, IBS, Grenoble, France
- CNRS, IBS, Grenoble, France
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149
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Ronchi D, Fassone E, Bordoni A, Sciacco M, Lucchini V, Di Fonzo A, Rizzuti M, Colombo I, Napoli L, Ciscato P, Moggio M, Cosi A, Collotta M, Corti S, Bresolin N, Comi GP. Two novel mutations in PEO1 (twinkle) gene associated with chronic external ophthalmoplegia. J Neurol Sci 2012; 308:173-6. [PMID: 21689831 PMCID: PMC3158327 DOI: 10.1016/j.jns.2011.05.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 12/02/2022]
Abstract
Maintenance and replication of mitochondrial DNA require the concerted action of several factors encoded by nuclear genome. The mitochondrial helicase Twinkle is a key player of replisome machinery. Heterozygous mutations in its coding gene, PEO1, are associated with progressive external ophthalmoplegia (PEO) characterised by ptosis and ophthalmoparesis, with cytochrome c oxidase (COX)-deficient fibres, ragged-red fibres (RRF) and multiple mtDNA deletions in muscle. Here we describe clinical, histological and molecular features of two patients presenting with mitochondrial myopathy associated with PEO. PEO1 sequencing disclosed two novel mutations in exons 1 and 4 of the gene, respectively. Although mutations in PEO1 exon 1 have already been described, this is the first report of mutation occurring in exon 4.
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Affiliation(s)
- Dario Ronchi
- Dino Ferrari Centre, Department of Neurological Sciences, University of Milan, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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150
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Abstract
BACKGROUND Mitochondrial respiratory chain disorders are the most prevalent group of inherited neurometabolic diseases. They present with central and peripheral neurological features usually in association with other organ involvement including the eye, the heart, the liver, and kidneys, diabetes mellitus and sensorineural deafness. Current treatment is largely supportive and the disorders progress relentlessly causing significant morbidity and premature death. Vitamin supplements, pharmacological agents and exercise therapy have been used in isolated cases and small clinical trials, but the efficacy of these interventions is unclear. The first review was carried out in 2003, and identified six clinical trials. This major update was carried out to identify new studies and grade the original studies for potential bias in accordance with revised Cochrane Collaboration guidelines. OBJECTIVES To determine whether there is objective evidence to support the use of current treatments for mitochondrial disease. SEARCH METHODS We searched the Cochrane Neuromuscular Disease Group Specialized Register (4 July 2011), CENTRAL (2011, Issue 2, MEDLINE (1966 to July 2011), and EMBASE (January 1980 to July 2011), and contacted experts in the field. SELECTION CRITERIA We included randomised controlled trials (including cross-over studies). Two of the authors independently selected abstracts for further detailed review. Further review was performed independently by all five authors to decide which trials fit the inclusion criteria and graded risk of bias. Participants included males and females of any age with a confirmed diagnosis of mitochondrial disease based upon muscle histochemistry, respiratory chain complex analysis of tissues or cell lines or DNA studies. Interventions included any pharmacological agent, dietary modification, nutritional supplement, exercise therapy or other treatment. The review authors excluded studies at high risk of bias in any category. The primary outcome measures included an change in muscle strength and/or endurance, or neurological clinical features. Secondary outcome measures included quality of life assessments, biochemical markers of disease and negative outcomes. DATA COLLECTION AND ANALYSIS Two of the authors (GP and PFC) independently identified studies for further evaluation from all abstracts within the search period. For those studies identified for further review, all five authors then independently assessed which studies met the entry criteria. For the included studies, we extracted details of the number of randomised participants, treatment, study design, study category, allocation concealment and other risk of bias criteria, and participant characteristics. Analysis was based on intention-to-treat data. We planned to use meta-analysis, but this did not prove necessary. MAIN RESULTS The authors reviewed 1335 abstracts, and from these identified 21 potentially eligible abstracts. Upon detailed review, 12 studies fulfilled the entry criteria. Of these, eight were new studies that had been published since the previous version of this review. Two studies which were included in the previous version of this review were excluded because of potential for bias. The comparability of the included studies is extremely low because of differences in the specific diseases studied, differences in the therapeutic agents used, dosage, study design, and outcomes. The methodological quality of included studies was generally high, although risk of bias was unclear in random sequence generation and allocation concealment for most studies. Otherwise, the risk of bias was low for most studies in the other categories. Serious adverse events were uncommon, except for peripheral nerve toxicity in a long-term trial of dichloroacetate (DCA) in adults.One trial studied high-dose coenzyme Q10 without clinically meaningful improvement (although there were multiple biochemical, physiologic, and neuroimaging outcomes, in 30 participants). Three trials used creatine monohydrate alone, with one reporting evidence of improved measures of muscle strength and post-exercise lactate, but the other two reported no benefit (total of 38 participants). One trial studied the effects of a combination of coenzyme Q10, creatine monohydrate, and lipoic acid and reported a statistically significant improvement in biochemical markers and peak ankle dorsiflexion strength, but overall no clinical improvement in 16 participants. Five trials studied the effects of DCA: three trials in children showed a statistically significant improvement in secondary outcome measures of mitochondrial metabolism (venous lactate in three trials, and magnetic resonance spectroscopy (MRS) in one trial; total of 63 participants). One trial of short-term DCA in adults demonstrated no clinically relevant improvement (improved venous lactate but no change in physiologic, imaging, or questionnaire findings, in eight participants). One longer-term DCA trial in adults was terminated prematurely due to peripheral nerve toxicity without clinical benefit (assessments included the GATE score, venous lactate and MRS, in 30 participants). One trial using dimethylglycine showed no significant effect (measurements of venous lactate and oxygen consumption (VO(2)) in five participants). One trial using a whey-based supplement showed statistically significant improvement in markers of free radical reducing capacity but no clinical benefit (assessments included the Short Form 36 Health Survey (SF-36) questionnaire and UK Medical Research Council (MRC) muscle strength, in 13 participants). AUTHORS' CONCLUSIONS Despite identifying eight new trials there is currently no clear evidence supporting the use of any intervention in mitochondrial disorders. Further research is needed to establish the role of a wide range of therapeutic approaches. We suggest further research should identify novel agents to be tested in homogeneous study populations with clinically relevant primary endpoints.
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Affiliation(s)
- Gerald Pfeffer
- Newcastle UniversityInstitute of Genetic MedicineCentral ParkwayNewcastle upon TyneUKNE1 3BZ
- University of British ColumbiaClinician Investigator ProgramVancouverBritish ColumbiaCanada
| | - Kari Majamaa
- University of OuluInstitute of Clinical Medicine, Department of NeurologyPO Box 5000OuluFinland
| | - Douglass M Turnbull
- Newcastle UniversityMitochondrial Research Group, The Medical SchoolFramlington PlaceNewcastle Upon TyneUKNE2 4HH
| | - David Thorburn
- Royal Children's HospitalMurdoch Children's Research Institute10th Floor Main BuildingFlemington Rd, ParkvilleVictoriaAustralia3052
| | - Patrick F Chinnery
- Newcastle UniversityInstitute of Genetic MedicineCentral ParkwayNewcastle upon TyneUKNE1 3BZ
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