1
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Späte E, Zhou B, Sun T, Kusch K, Asadollahi E, Siems SB, Depp C, Werner HB, Saher G, Hirrlinger J, Möbius W, Nave KA, Goebbels S. Downregulated expression of lactate dehydrogenase in adult oligodendrocytes and its implication for the transfer of glycolysis products to axons. Glia 2024; 72:1374-1391. [PMID: 38587131 DOI: 10.1002/glia.24533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/09/2024]
Abstract
Oligodendrocytes and astrocytes are metabolically coupled to neuronal compartments. Pyruvate and lactate can shuttle between glial cells and axons via monocarboxylate transporters. However, lactate can only be synthesized or used in metabolic reactions with the help of lactate dehydrogenase (LDH), a tetramer of LDHA and LDHB subunits in varying compositions. Here we show that mice with a cell type-specific disruption of both Ldha and Ldhb genes in oligodendrocytes lack a pathological phenotype that would be indicative of oligodendroglial dysfunctions or lack of axonal metabolic support. Indeed, when combining immunohistochemical, electron microscopical, and in situ hybridization analyses in adult mice, we found that the vast majority of mature oligodendrocytes lack detectable expression of LDH. Even in neurodegenerative disease models and in mice under metabolic stress LDH was not increased. In contrast, at early development and in the remyelinating brain, LDHA was readily detectable in immature oligodendrocytes. Interestingly, by immunoelectron microscopy LDHA was particularly enriched at gap junctions formed between adjacent astrocytes and at junctions between astrocytes and oligodendrocytes. Our data suggest that oligodendrocytes metabolize lactate during development and remyelination. In contrast, for metabolic support of axons mature oligodendrocytes may export their own glycolysis products as pyruvate rather than lactate. Lacking LDH, these oligodendrocytes can also "funnel" lactate through their "myelinic" channels between gap junction-coupled astrocytes and axons without metabolizing it. We suggest a working model, in which the unequal cellular distribution of LDH in white matter tracts facilitates a rapid and efficient transport of glycolysis products among glial and axonal compartments.
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Affiliation(s)
- Erik Späte
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Baoyu Zhou
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Laboratory of Molecular Neurobiology, Department of Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Ebrahim Asadollahi
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sophie B Siems
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Constanze Depp
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Gesine Saher
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Johannes Hirrlinger
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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2
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Caron-Godon CA, Collington E, Wolf JL, Coletta G, Glerum DM. More than Just Bread and Wine: Using Yeast to Understand Inherited Cytochrome Oxidase Deficiencies in Humans. Int J Mol Sci 2024; 25:3814. [PMID: 38612624 PMCID: PMC11011759 DOI: 10.3390/ijms25073814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 03/26/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Inherited defects in cytochrome c oxidase (COX) are associated with a substantial subset of diseases adversely affecting the structure and function of the mitochondrial respiratory chain. This multi-subunit enzyme consists of 14 subunits and numerous cofactors, and it requires the function of some 30 proteins to assemble. COX assembly was first shown to be the primary defect in the majority of COX deficiencies 36 years ago. Over the last three decades, most COX assembly genes have been identified in the yeast Saccharomyces cerevisiae, and studies in yeast have proven instrumental in testing the impact of mutations identified in patients with a specific COX deficiency. The advent of accessible genome-wide sequencing capabilities has led to more patient mutations being identified, with the subsequent identification of several new COX assembly factors. However, the lack of genotype-phenotype correlations and the large number of genes involved in generating a functional COX mean that functional studies must be undertaken to assign a genetic variant as being causal. In this review, we provide a brief overview of the use of yeast as a model system and briefly compare the COX assembly process in yeast and humans. We focus primarily on the studies in yeast that have allowed us to both identify new COX assembly factors and to demonstrate the pathogenicity of a subset of the mutations that have been identified in patients with inherited defects in COX. We conclude with an overview of the areas in which studies in yeast are likely to continue to contribute to progress in understanding disease arising from inherited COX deficiencies.
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Affiliation(s)
- Chenelle A. Caron-Godon
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - Emma Collington
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - Jessica L. Wolf
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - Genna Coletta
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
| | - D. Moira Glerum
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada; (C.A.C.-G.); (E.C.); (J.L.W.); (G.C.)
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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3
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Lopriore P, Ricciarini V, Siciliano G, Mancuso M, Montano V. Mitochondrial Ataxias: Molecular Classification and Clinical Heterogeneity. Neurol Int 2022; 14:337-356. [PMID: 35466209 PMCID: PMC9036286 DOI: 10.3390/neurolint14020028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 01/25/2023] Open
Abstract
Ataxia is increasingly being recognized as a cardinal manifestation in primary mitochondrial diseases (PMDs) in both paediatric and adult patients. It can be caused by disruption of cerebellar nuclei or fibres, its connection with the brainstem, or spinal and peripheral lesions leading to proprioceptive loss. Despite mitochondrial ataxias having no specific defining features, they should be included in hereditary ataxias differential diagnosis, given the high prevalence of PMDs. This review focuses on the clinical and neuropathological features and genetic background of PMDs in which ataxia is a prominent manifestation.
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4
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Garcia S, Saldana-Caboverde A, Anwar M, Raval AP, Nissanka N, Pinto M, Moraes CT, Diaz F. Enhanced glycolysis and GSK3 inactivation promote brain metabolic adaptations following neuronal mitochondrial stress. Hum Mol Genet 2021; 31:692-704. [PMID: 34559217 DOI: 10.1093/hmg/ddab282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/10/2021] [Accepted: 09/17/2021] [Indexed: 11/14/2022] Open
Abstract
We analyzed early brain metabolic adaptations in response to mitochondrial dysfunction in a mouse model of mitochondrial encephalopathy with complex IV deficiency (neuron specific COX10 KO). In this mouse model the onset of the mitochondrial defect did not coincide with immediate cell death suggesting early adaptive metabolic responses to compensate for the energetic deficit. Metabolomic analysis in the knockout mice revealed increased levels of glycolytic and pentose phosphate pathway intermediates, amino acids and lysolipids. Glycolysis was modulated by enhanced activity of glycolytic enzymes, and not by their overexpression, suggesting the importance of post-translational modifications in the adaptive response. GSK3 inactivation was the most upstream regulation identified, implying that it is a key event in this adaptive mechanism. Because neurons are thought not to rely on glycolysis for ATP production in normal conditions, our results indicate that neurons still maintain their ability to upregulate this pathway when under mitochondrial respiration stress.
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Affiliation(s)
- Sofia Garcia
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Amy Saldana-Caboverde
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Mir Anwar
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Ami Pravinkant Raval
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Nadee Nissanka
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Milena Pinto
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Carlos Torres Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida 33136
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5
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Dietz JV, Fox JL, Khalimonchuk O. Down the Iron Path: Mitochondrial Iron Homeostasis and Beyond. Cells 2021; 10:cells10092198. [PMID: 34571846 PMCID: PMC8468894 DOI: 10.3390/cells10092198] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
Abstract
Cellular iron homeostasis and mitochondrial iron homeostasis are interdependent. Mitochondria must import iron to form iron–sulfur clusters and heme, and to incorporate these cofactors along with iron ions into mitochondrial proteins that support essential functions, including cellular respiration. In turn, mitochondria supply the cell with heme and enable the biogenesis of cytosolic and nuclear proteins containing iron–sulfur clusters. Impairment in cellular or mitochondrial iron homeostasis is deleterious and can result in numerous human diseases. Due to its reactivity, iron is stored and trafficked through the body, intracellularly, and within mitochondria via carefully orchestrated processes. Here, we focus on describing the processes of and components involved in mitochondrial iron trafficking and storage, as well as mitochondrial iron–sulfur cluster biogenesis and heme biosynthesis. Recent findings and the most pressing topics for future research are highlighted.
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Affiliation(s)
- Jonathan V. Dietz
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
| | - Jennifer L. Fox
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424, USA;
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
- Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
- Fred and Pamela Buffett Cancer Center, Omaha, NE 68198, USA
- Correspondence:
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6
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Zanfardino P, Doccini S, Santorelli FM, Petruzzella V. Tackling Dysfunction of Mitochondrial Bioenergetics in the Brain. Int J Mol Sci 2021; 22:8325. [PMID: 34361091 PMCID: PMC8348117 DOI: 10.3390/ijms22158325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/15/2022] Open
Abstract
Oxidative phosphorylation (OxPhos) is the basic function of mitochondria, although the landscape of mitochondrial functions is continuously growing to include more aspects of cellular homeostasis. Thanks to the application of -omics technologies to the study of the OxPhos system, novel features emerge from the cataloging of novel proteins as mitochondrial thus adding details to the mitochondrial proteome and defining novel metabolic cellular interrelations, especially in the human brain. We focussed on the diversity of bioenergetics demand and different aspects of mitochondrial structure, functions, and dysfunction in the brain. Definition such as 'mitoexome', 'mitoproteome' and 'mitointeractome' have entered the field of 'mitochondrial medicine'. In this context, we reviewed several genetic defects that hamper the last step of aerobic metabolism, mostly involving the nervous tissue as one of the most prominent energy-dependent tissues and, as consequence, as a primary target of mitochondrial dysfunction. The dual genetic origin of the OxPhos complexes is one of the reasons for the complexity of the genotype-phenotype correlation when facing human diseases associated with mitochondrial defects. Such complexity clinically manifests with extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. Finally, we briefly discuss the future directions of the multi-omics study of human brain disorders.
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Affiliation(s)
- Paola Zanfardino
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
| | - Stefano Doccini
- IRCCS Fondazione Stella Maris, Calambrone, 56128 Pisa, Italy;
| | | | - Vittoria Petruzzella
- Department of Medical Basic Sciences, Neurosciences and Sense Organs, University of Bari Aldo Moro, 70124 Bari, Italy;
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7
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Fernandez-Vizarra E, Zeviani M. Mitochondrial disorders of the OXPHOS system. FEBS Lett 2020; 595:1062-1106. [PMID: 33159691 DOI: 10.1002/1873-3468.13995] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/21/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022]
Abstract
Mitochondrial disorders are among the most frequent inborn errors of metabolism, their primary cause being the dysfunction of the oxidative phosphorylation system (OXPHOS). OXPHOS is composed of the electron transport chain (ETC), formed by four multimeric enzymes and two mobile electron carriers, plus an ATP synthase [also called complex V (cV)]. The ETC performs the redox reactions involved in cellular respiration while generating the proton motive force used by cV to synthesize ATP. OXPHOS biogenesis involves multiple steps, starting from the expression of genes encoded in physically separated genomes, namely the mitochondrial and nuclear DNA, to the coordinated assembly of components and cofactors building each individual complex and eventually the supercomplexes. The genetic cause underlying around half of the diagnosed mitochondrial disease cases is currently known. Many of these cases result from pathogenic variants in genes encoding structural subunits or additional factors directly involved in the assembly of the ETC complexes. Here, we review the historical and most recent findings concerning the clinical phenotypes and the molecular pathological mechanisms underlying this particular group of disorders.
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Affiliation(s)
- Erika Fernandez-Vizarra
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK
| | - Massimo Zeviani
- Venetian Institute of Molecular Medicine, Padova, Italy.,Department of Neurosciences, University of Padova, Italy
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8
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Human Mitochondrial Pathologies of the Respiratory Chain and ATP Synthase: Contributions from Studies of Saccharomyces cerevisiae. Life (Basel) 2020; 10:life10110304. [PMID: 33238568 PMCID: PMC7700678 DOI: 10.3390/life10110304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/14/2022] Open
Abstract
The ease with which the unicellular yeast Saccharomyces cerevisiae can be manipulated genetically and biochemically has established this organism as a good model for the study of human mitochondrial diseases. The combined use of biochemical and molecular genetic tools has been instrumental in elucidating the functions of numerous yeast nuclear gene products with human homologs that affect a large number of metabolic and biological processes, including those housed in mitochondria. These include structural and catalytic subunits of enzymes and protein factors that impinge on the biogenesis of the respiratory chain. This article will review what is currently known about the genetics and clinical phenotypes of mitochondrial diseases of the respiratory chain and ATP synthase, with special emphasis on the contribution of information gained from pet mutants with mutations in nuclear genes that impair mitochondrial respiration. Our intent is to provide the yeast mitochondrial specialist with basic knowledge of human mitochondrial pathologies and the human specialist with information on how genes that directly and indirectly affect respiration were identified and characterized in yeast.
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9
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Cytochrome c oxidase deficiency. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148335. [PMID: 33171185 DOI: 10.1016/j.bbabio.2020.148335] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/31/2020] [Accepted: 11/03/2020] [Indexed: 12/23/2022]
Abstract
Cytochrome c oxidase (COX) deficiency is characterized by a high degree of genetic and phenotypic heterogeneity, partly reflecting the extreme structural complexity, multiple post-translational modification, variable, tissue-specific composition, and the high number of and intricate connections among the assembly factors of this enzyme. In fact, decreased COX specific activity can manifest with different degrees of severity, affect the whole organism or specific tissues, and develop a wide spectrum of disease natural history, including disease onsets ranging from birth to late adulthood. More than 30 genes have been linked to COX deficiency, but the list is still incomplete and in fact constantly updated. We here discuss the current knowledge about COX in health and disease, focusing on genetic aetiology and link to clinical manifestations. In addition, information concerning either fundamental biological features of the enzymes or biochemical signatures of its defects have been provided by experimental in vivo models, including yeast, fly, mouse and fish, which expanded our knowledge on the functional features and the phenotypical consequences of different forms of COX deficiency.
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10
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Functions of Cytochrome c oxidase Assembly Factors. Int J Mol Sci 2020; 21:ijms21197254. [PMID: 33008142 PMCID: PMC7582755 DOI: 10.3390/ijms21197254] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 09/23/2020] [Indexed: 12/22/2022] Open
Abstract
Cytochrome c oxidase is the terminal complex of eukaryotic oxidative phosphorylation in mitochondria. This process couples the reduction of electron carriers during metabolism to the reduction of molecular oxygen to water and translocation of protons from the internal mitochondrial matrix to the inter-membrane space. The electrochemical gradient formed is used to generate chemical energy in the form of adenosine triphosphate to power vital cellular processes. Cytochrome c oxidase and most oxidative phosphorylation complexes are the product of the nuclear and mitochondrial genomes. This poses a series of topological and temporal steps that must be completed to ensure efficient assembly of the functional enzyme. Many assembly factors have evolved to perform these steps for insertion of protein into the inner mitochondrial membrane, maturation of the polypeptide, incorporation of co-factors and prosthetic groups and to regulate this process. Much of the information about each of these assembly factors has been gleaned from use of the single cell eukaryote Saccharomyces cerevisiae and also mutations responsible for human disease. This review will focus on the assembly factors of cytochrome c oxidase to highlight some of the outstanding questions in the assembly of this vital enzyme complex.
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11
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Koripella RK, Sharma MR, Bhargava K, Datta PP, Kaushal PS, Keshavan P, Spremulli LL, Banavali NK, Agrawal RK. Structures of the human mitochondrial ribosome bound to EF-G1 reveal distinct features of mitochondrial translation elongation. Nat Commun 2020; 11:3830. [PMID: 32737313 PMCID: PMC7395135 DOI: 10.1038/s41467-020-17715-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/15/2020] [Indexed: 02/06/2023] Open
Abstract
The mammalian mitochondrial ribosome (mitoribosome) and its associated translational factors have evolved to accommodate greater participation of proteins in mitochondrial translation. Here we present the 2.68-3.96 Å cryo-EM structures of the human 55S mitoribosome in complex with the human mitochondrial elongation factor G1 (EF-G1mt) in three distinct conformational states, including an intermediate state and a post-translocational state. These structures reveal the role of several mitochondria-specific (mito-specific) mitoribosomal proteins (MRPs) and a mito-specific segment of EF-G1mt in mitochondrial tRNA (tRNAmt) translocation. In particular, the mito-specific C-terminal extension in EF-G1mt is directly involved in translocation of the acceptor arm of the A-site tRNAmt. In addition to the ratchet-like and independent head-swiveling motions exhibited by the small mitoribosomal subunit, we discover significant conformational changes in MRP mL45 at the nascent polypeptide-exit site within the large mitoribosomal subunit that could be critical for tethering of the elongating mitoribosome onto the inner-mitochondrial membrane.
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MESH Headings
- Amino Acid Sequence
- Binding Sites
- Cryoelectron Microscopy
- HEK293 Cells
- Humans
- Mitochondria/metabolism
- Mitochondria/ultrastructure
- Mitochondrial Membranes/metabolism
- Mitochondrial Membranes/ultrastructure
- Mitochondrial Proteins/chemistry
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Models, Molecular
- Nucleic Acid Conformation
- Peptide Chain Elongation, Translational
- Peptide Elongation Factor G/chemistry
- Peptide Elongation Factor G/genetics
- Peptide Elongation Factor G/metabolism
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- RNA, Mitochondrial/chemistry
- RNA, Mitochondrial/genetics
- RNA, Mitochondrial/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Ribosomal Proteins/chemistry
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomes/metabolism
- Ribosomes/ultrastructure
- Sequence Alignment
- Sequence Homology, Amino Acid
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Affiliation(s)
- Ravi Kiran Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
| | - Manjuli R Sharma
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
| | - Kalpana Bhargava
- Department of Chemistry, Campus Box 3290, University of North Carolina, Chapel Hill, NC, USA
- High Energy Material Research Lab, Defense Research and Development Organization, Sutarwadi, Pashan, Pune, Maharashtra, 411021, India
| | - Partha P Datta
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India
| | - Prem S Kaushal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
- Regional Centre for Biotechnology, 3rd Milestone, Faridabad-Gurgaon Expressway, PO Box # 3, Faridabad, Haryana, 121001, India
| | - Pooja Keshavan
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
| | - Linda L Spremulli
- Department of Chemistry, Campus Box 3290, University of North Carolina, Chapel Hill, NC, USA
| | - Nilesh K Banavali
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY, 12201-0509, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY, 12201, USA.
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY, 12201-0509, USA.
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12
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Mani S, Chandak GR, Singh KK, Singh R, Rao SN. Novel p.P298L SURF1 mutation in thiamine deficient Leigh syndrome patients compromises cytochrome c oxidase activity. Mitochondrion 2020; 53:91-98. [PMID: 32380162 DOI: 10.1016/j.mito.2020.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/20/2020] [Accepted: 04/29/2020] [Indexed: 01/15/2023]
Abstract
SURF1 is a nuclear gene and encodes for an important assembly factor for cytochrome c oxidase enzyme. A number of mutations in SURF1 gene render cytochrome c oxidase deficiency, a major causative factor for Leigh syndrome. We screened all the 9 exons and exon-intron boundaries of SURF1 gene in 165 Indian Leigh syndrome patients who were thiamine responsive too. Consequently, we identified several novel and reported nucleotide variations in this gene. The nucleotide changes were analysed by using different in-silico tools for predicting their pathogenicity. Based upon the predictions, we further validated the analyzed functional significance of p.N249D and p.P298L mutations in SURF1 protein using COS-7 cells. Though, both the mutations did not affect the localization of SURF1protein into the mitochondria. But, interestingly the novel mutation p.P298L was reported to significantly compromise the COX activity in these cells.
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Affiliation(s)
- Shalini Mani
- Department of Biotechnology, Centre for Emerging Disease, Jaypee Institute of Information Technology, Noida, India; CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India.
| | - G R Chandak
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Keshav K Singh
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rajender Singh
- Division of Endocrinology, Central Drug Research Institute, Lucknow, India
| | - S Narasimha Rao
- Government Institute of Child Health, Niloufer Hospital for Women and Children, Red Hills, Hyderabad, India
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13
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From Synthesis to Utilization: The Ins and Outs of Mitochondrial Heme. Cells 2020; 9:cells9030579. [PMID: 32121449 PMCID: PMC7140478 DOI: 10.3390/cells9030579] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 12/14/2022] Open
Abstract
Heme is a ubiquitous and essential iron containing metallo-organic cofactor required for virtually all aerobic life. Heme synthesis is initiated and completed in mitochondria, followed by certain covalent modifications and/or its delivery to apo-hemoproteins residing throughout the cell. While the biochemical aspects of heme biosynthetic reactions are well understood, the trafficking of newly synthesized heme—a highly reactive and inherently toxic compound—and its subsequent delivery to target proteins remain far from clear. In this review, we summarize current knowledge about heme biosynthesis and trafficking within and outside of the mitochondria.
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14
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Tesarova M, Vondrackova A, Stufkova H, Veprekova L, Stranecky V, Berankova K, Hansikova H, Magner M, Galoova N, Honzik T, Vodickova E, Stary J, Zeman J. Sideroblastic anemia associated with multisystem mitochondrial disorders. Pediatr Blood Cancer 2019; 66:e27591. [PMID: 30588737 DOI: 10.1002/pbc.27591] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/18/2018] [Accepted: 11/29/2018] [Indexed: 01/19/2023]
Abstract
BACKGROUND Sideroblastic anemia represents a heterogeneous group of inherited or acquired diseases with disrupted erythroblast iron utilization, ineffective erythropoiesis, and variable systemic iron overload. In a cohort of 421 patients with multisystem mitochondrial diseases, refractory anemia was found in 8 children. RESULTS Five children had sideroblastic anemia with increased numbers of ring sideroblasts >15%. Two of the children had a fatal course of MLASA1 syndrome (mitochondrial myopathy, lactic acidosis, and sideroblastic anemia [SA]) due to a homozygous, 6-kb deletion in the PUS1 gene, part of the six-member family of pseudouridine synthases (pseudouridylases). Large homozygous deletions represent a novel cause of presumed PUS1-loss-of-function phenotype. The other three children with SA had Pearson syndrome (PS) due to mtDNA deletions of 4 to 8 kb; two of these children showed early onset of PS and died due to repeated sepsis; the other child had later onset of PS and survived as the hematological parameters normalized and the disease transitioned to Kearns-Sayre syndrome. In addition, anemia without ring sideroblasts was found in three other patients with mitochondrial disorders, including two children with later onset of PS and one child with failure to thrive, microcephaly, developmental delay, hypertrophic cardiomyopathy, and renal tubular acidosis due to the heterozygous mutations c.610A>G (p.Asn204Asp) and c.674C>T (p.Pro225Leu) in the COX10 gene encoding the cytochrome c oxidase assembly factor. CONCLUSIONS Sideroblastic anemia was found in fewer than 1.2% of patients with multisystem mitochondrial disease, and it was usually associated with an unfavorable prognosis.
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Affiliation(s)
- Marketa Tesarova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Alzbeta Vondrackova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Hana Stufkova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Lenka Veprekova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Viktor Stranecky
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Kamila Berankova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Hana Hansikova
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Martin Magner
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Natalia Galoova
- Department of Paediatric Oncology and Haematology, Children's University Hospital, Kosice, Slovakia
| | - Tomas Honzik
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - Elena Vodickova
- Department of Haematology, Motol University Hospital, Prague, Czech Republic
| | - Jan Stary
- Department of Paediatric Haematology and Oncology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic
| | - Jiri Zeman
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
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15
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Baek JH, Gomez IG, Wada Y, Roach A, Mahad D, Duffield JS. Deletion of the Mitochondrial Complex-IV Cofactor Heme A:Farnesyltransferase Causes Focal Segmental Glomerulosclerosis and Interferon Response. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:2745-2762. [PMID: 30268775 DOI: 10.1016/j.ajpath.2018.08.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/02/2018] [Accepted: 08/06/2018] [Indexed: 01/31/2023]
Abstract
Mutations in mitochondrial DNA as well as nuclear-encoded mitochondrial proteins have been reported to cause tubulointerstitial kidney diseases and focal segmental glomerulosclerosis (FSGS). Recently, genes and pathways affecting mitochondrial turnover and permeability have been implicated in adult-onset FSGS. Furthermore, dysfunctioning mitochondria may be capable of engaging intracellular innate immune-sensing pathways. To determine the impact of mitochondrial dysfunction in FSGS and secondary innate immune responses, we generated Cre/loxP transgenic mice to generate a loss-of-function deletion mutation of the complex IV assembly cofactor heme A:farnesyltransferase (COX10) restricted to cells of the developing nephrons. These mice develop severe, early-onset FSGS with innate immune activation and die prematurely with kidney failure. Mutant kidneys showed loss of glomerular and tubular epithelial function, epithelial apoptosis, and, in addition, a marked interferon response. In vitro modeling of Cox10 deletion in primary kidney epithelium compromises oxygen consumption, ATP generation, and induces oxidative stress. In addition, loss of Cox10 triggers a selective interferon response, which may be caused by the leak of mitochondrial DNA into the cytosol activating the intracellular DNA sensor, stimulator of interferon genes. This new animal model provides a mechanism to study mitochondrial dysfunction in vivo and demonstrates a direct link between mitochondrial dysfunction and intracellular innate immune response.
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Affiliation(s)
- Jea-Hyun Baek
- Research and Development, Biogen Inc., Cambridge, Massachusetts.
| | - Ivan G Gomez
- Research and Development, Biogen Inc., Cambridge, Massachusetts; Division of Nephrology, Departments of Medicine and Pathology, University of Washington, Seattle, Washington
| | - Yukihiro Wada
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
| | - Allie Roach
- Research and Development, Biogen Inc., Cambridge, Massachusetts; Division of Nephrology, Departments of Medicine and Pathology, University of Washington, Seattle, Washington
| | - Don Mahad
- Centre for Clinical Brain Sciences, Anne Rowling Regenerative Neurology Clinic and Centre for Neuroregeneration, University of Edinburgh, Edinburgh, United Kingdom
| | - Jeremy S Duffield
- Research and Development, Biogen Inc., Cambridge, Massachusetts; Division of Nephrology, Departments of Medicine and Pathology, University of Washington, Seattle, Washington; Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts.
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16
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Kapnick SM, Pacheco SE, McGuire PJ. The emerging role of immune dysfunction in mitochondrial diseases as a paradigm for understanding immunometabolism. Metabolism 2018; 81:97-112. [PMID: 29162500 PMCID: PMC5866745 DOI: 10.1016/j.metabol.2017.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/07/2017] [Accepted: 11/11/2017] [Indexed: 01/08/2023]
Abstract
Immunometabolism aims to define the role of intermediary metabolism in immune cell function, with bioenergetics and the mitochondria recently taking center stage. To date, the medical literature on mitochondria and immune function extols the virtues of mouse models in exploring this biologic intersection. While the laboratory mouse has become a standard for studying mammalian biology, this model comprises part of a comprehensive approach. Humans, with their broad array of inherited phenotypes, serve as a starting point for studying immunometabolism; specifically, patients with mitochondrial disease. Using this top-down approach, the mouse as a model organism facilitates further exploration of the consequences of mutations involved in mitochondrial maintenance and function. In this review, we will discuss the emerging phenotype of immune dysfunction in mitochondrial disease as a model for understanding the role of the mitochondria in immune function in available mouse models.
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Affiliation(s)
- Senta M Kapnick
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Susan E Pacheco
- Department of Pediatrics, The University of Texas Health Science Center, Houston, TX, USA
| | - Peter J McGuire
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
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17
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Tissue- and Condition-Specific Isoforms of Mammalian Cytochrome c Oxidase Subunits: From Function to Human Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:1534056. [PMID: 28593021 PMCID: PMC5448071 DOI: 10.1155/2017/1534056] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/29/2017] [Indexed: 01/05/2023]
Abstract
Cytochrome c oxidase (COX) is the terminal enzyme of the electron transport chain and catalyzes the transfer of electrons from cytochrome c to oxygen. COX consists of 14 subunits, three and eleven encoded, respectively, by the mitochondrial and nuclear DNA. Tissue- and condition-specific isoforms have only been reported for COX but not for the other oxidative phosphorylation complexes, suggesting a fundamental requirement to fine-tune and regulate the essentially irreversible reaction catalyzed by COX. This article briefly discusses the assembly of COX in mammals and then reviews the functions of the six nuclear-encoded COX subunits that are expressed as isoforms in specialized tissues including those of the liver, heart and skeletal muscle, lung, and testes: COX IV-1, COX IV-2, NDUFA4, NDUFA4L2, COX VIaL, COX VIaH, COX VIb-1, COX VIb-2, COX VIIaH, COX VIIaL, COX VIIaR, COX VIIIH/L, and COX VIII-3. We propose a model in which the isoforms mediate the interconnected regulation of COX by (1) adjusting basal enzyme activity to mitochondrial capacity of a given tissue; (2) allosteric regulation to adjust energy production to need; (3) altering proton pumping efficiency under certain conditions, contributing to thermogenesis; (4) providing a platform for tissue-specific signaling; (5) stabilizing the COX dimer; and (6) modulating supercomplex formation.
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18
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Peralta S, Garcia S, Yin HY, Arguello T, Diaz F, Moraes CT. Sustained AMPK activation improves muscle function in a mitochondrial myopathy mouse model by promoting muscle fiber regeneration. Hum Mol Genet 2016; 25:3178-3191. [PMID: 27288451 PMCID: PMC5179920 DOI: 10.1093/hmg/ddw167] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/22/2016] [Accepted: 05/23/2016] [Indexed: 12/25/2022] Open
Abstract
Acute pharmacological activation of adenosine monophosphate (AMP)-kinase using 5-aminoimidazole-4-carboxamide-1-b-D-ribofuranoside (AICAR) has been shown to improve muscle mitochondrial function by increasing mitochondrial biogenesis. We asked whether prolonged AICAR treatment is beneficial in a mouse model of slowly progressing mitochondrial myopathy (Cox10-Mef2c-Cre), and whether the compensatory mechanism is indeed an increase in mitochondrial biogenesis. We treated the animals for 3 months and found that sustained AMP-dependent kinase activation improved cytochrome c oxidase activity, rescued the motor phenotype and delayed the onset of the myopathy. This improvement was observed whether treatment started before or after the onset of the disease. We found that AICAR increased skeletal muscle regeneration thereby decreasing the levels of deleted Cox10-floxed alleles. We conclude that although increase in mitochondrial biogenesis and other pathways may contribute, the main mechanism by which AICAR improves the myopathy phenotype is by promoting muscle regeneration.
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Affiliation(s)
| | | | | | | | | | - Carlos T Moraes
- Department of Neurology
- Genetics Graduate Program
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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19
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Swenson S, Cannon A, Harris NJ, Taylor NG, Fox JL, Khalimonchuk O. Analysis of Oligomerization Properties of Heme a Synthase Provides Insights into Its Function in Eukaryotes. J Biol Chem 2016; 291:10411-25. [PMID: 26940873 DOI: 10.1074/jbc.m115.707539] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Indexed: 11/06/2022] Open
Abstract
Heme a is an essential cofactor for function of cytochrome c oxidase in the mitochondrial electron transport chain. Several evolutionarily conserved enzymes have been implicated in the biosynthesis of heme a, including the heme a synthase Cox15. However, the structure of Cox15 is unknown, its enzymatic mechanism and the role of active site residues remain debated, and recent discoveries suggest additional chaperone-like roles for this enzyme. Here, we investigated Cox15 in the model eukaryote Saccharomyces cerevisiae via several approaches to examine its oligomeric states and determine the effects of active site and human pathogenic mutations. Our results indicate that Cox15 exhibits homotypic interactions, forming highly stable complexes dependent upon hydrophobic interactions. This multimerization is evolutionarily conserved and independent of heme levels and heme a synthase catalytic activity. Four conserved histidine residues are demonstrated to be critical for eukaryotic heme a synthase activity and cannot be substituted with other heme-ligating amino acids. The 20-residue linker region connecting the two conserved domains of Cox15 is also important; removal of this linker impairs both Cox15 multimerization and enzymatic activity. Mutations of COX15 causing single amino acid conversions associated with fatal infantile hypertrophic cardiomyopathy and the neurological disorder Leigh syndrome result in impaired stability (S344P) or catalytic function (R217W), and the latter mutation affects oligomeric properties of the enzyme. Structural modeling of Cox15 suggests these two mutations affect protein folding and heme binding, respectively. We conclude that Cox15 multimerization is important for heme a biosynthesis and/or transfer to maturing cytochrome c oxidase.
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Affiliation(s)
- Samantha Swenson
- From the Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 and
| | - Andrew Cannon
- From the Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 and
| | - Nicholas J Harris
- the Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424
| | - Nicholas G Taylor
- the Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424
| | - Jennifer L Fox
- the Department of Chemistry and Biochemistry, College of Charleston, Charleston, South Carolina 29424
| | - Oleh Khalimonchuk
- From the Department of Biochemistry and Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 and
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20
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Torraco A, Peralta S, Iommarini L, Diaz F. Mitochondrial Diseases Part I: mouse models of OXPHOS deficiencies caused by defects in respiratory complex subunits or assembly factors. Mitochondrion 2015; 21:76-91. [PMID: 25660179 DOI: 10.1016/j.mito.2015.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/22/2014] [Accepted: 01/05/2015] [Indexed: 10/24/2022]
Abstract
Mitochondrial disorders are the most common inborn errors of metabolism affecting the oxidative phosphorylation system (OXPHOS). Because of the poor knowledge of the pathogenic mechanisms, a cure for these disorders is still unavailable and all the treatments currently in use are supportive more than curative. Therefore, in the past decade a great variety of mouse models have been developed to assess the in vivo function of several mitochondrial proteins involved in human diseases. Due to the genetic and physiological similarity to humans, mice represent reliable models to study the pathogenic mechanisms of mitochondrial disorders and are precious to test new therapeutic approaches. Here we summarize the features of several mouse models of mitochondrial diseases directly related to defects in subunits of the OXPHOS complexes or in assembly factors. We discuss how these models recapitulate many human conditions and how they have contributed to the understanding of mitochondrial function in health and disease.
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Affiliation(s)
- 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.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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21
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Lim SC, Friemel M, Marum JE, Tucker EJ, Bruno DL, Riley LG, Christodoulou J, Kirk EP, Boneh A, DeGennaro CM, Springer M, Mootha VK, Rouault TA, Leimkühler S, Thorburn DR, Compton AG. Mutations in LYRM4, encoding iron-sulfur cluster biogenesis factor ISD11, cause deficiency of multiple respiratory chain complexes. Hum Mol Genet 2013; 22:4460-73. [PMID: 23814038 DOI: 10.1093/hmg/ddt295] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Iron-sulfur clusters (ISCs) are important prosthetic groups that define the functions of many proteins. Proteins with ISCs (called iron-sulfur or Fe-S proteins) are present in mitochondria, the cytosol, the endoplasmic reticulum and the nucleus. They participate in various biological pathways including oxidative phosphorylation (OXPHOS), the citric acid cycle, iron homeostasis, heme biosynthesis and DNA repair. Here, we report a homozygous mutation in LYRM4 in two patients with combined OXPHOS deficiency. LYRM4 encodes the ISD11 protein, which forms a complex with, and stabilizes, the sulfur donor NFS1. The homozygous mutation (c.203G>T, p.R68L) was identified via massively parallel sequencing of >1000 mitochondrial genes (MitoExome sequencing) in a patient with deficiency of complexes I, II and III in muscle and liver. These three complexes contain ISCs. Sanger sequencing identified the same mutation in his similarly affected cousin, who had a more severe phenotype and died while a neonate. Complex IV was also deficient in her skeletal muscle. Several other Fe-S proteins were also affected in both patients, including the aconitases and ferrochelatase. Mutant ISD11 only partially complemented for an ISD11 deletion in yeast. Our in vitro studies showed that the l-cysteine desulfurase activity of NFS1 was barely present when co-expressed with mutant ISD11. Our findings are consistent with a defect in the early step of ISC assembly affecting a broad variety of Fe-S proteins. The differences in biochemical and clinical features between the two patients may relate to limited availability of cysteine in the newborn period and suggest a potential approach to therapy.
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Affiliation(s)
- Sze Chern Lim
- Murdoch Childrens Research Institute, Royal Children's Hospital, Flemington Road, Parkville, VIC 3052, Australia
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22
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Abstract
INTRODUCTION In the last 10 years the field of mitochondrial genetics has widened, shifting the focus from rare sporadic, metabolic disease to the effects of mitochondrial DNA (mtDNA) variation in a growing spectrum of human disease. The aim of this review is to guide the reader through some key concepts regarding mitochondria before introducing both classic and emerging mitochondrial disorders. SOURCES OF DATA In this article, a review of the current mitochondrial genetics literature was conducted using PubMed (http://www.ncbi.nlm.nih.gov/pubmed/). In addition, this review makes use of a growing number of publically available databases including MITOMAP, a human mitochondrial genome database (www.mitomap.org), the Human DNA polymerase Gamma Mutation Database (http://tools.niehs.nih.gov/polg/) and PhyloTree.org (www.phylotree.org), a repository of global mtDNA variation. AREAS OF AGREEMENT The disruption in cellular energy, resulting from defects in mtDNA or defects in the nuclear-encoded genes responsible for mitochondrial maintenance, manifests in a growing number of human diseases. AREAS OF CONTROVERSY The exact mechanisms which govern the inheritance of mtDNA are hotly debated. GROWING POINTS Although still in the early stages, the development of in vitro genetic manipulation could see an end to the inheritance of the most severe mtDNA disease.
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Affiliation(s)
| | - Gavin Hudson
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne NE1 3BZ, UK
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23
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Luo LF, Hou CC, Yang WX. Nuclear factors: roles related to mitochondrial deafness. Gene 2013; 520:79-89. [PMID: 23510774 DOI: 10.1016/j.gene.2013.03.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 03/08/2013] [Indexed: 12/16/2022]
Abstract
Hearing loss (HL) is a common disorder with mitochondrial dysfunction as one of the major causes leading to deafness. Mitochondrial dysfunction may be caused by either mutations in nuclear genes leading to defective nuclear-encoded proteins or mutations in mitochondrial genes leading to defective mitochondrial-encoded products. The specific nuclear genes involved in HL can be classified into two categories depending on whether mitochondrial gene mutations co-exist (modifier genes) or not (deafness-causing genes). TFB1M, MTO1, GTPBP3, and TRMU are modifier genes. A mutation in any of these modifier genes may lead to a deafness phenotype when accompanied by the mitochondrial gene mutation. OPA1, TIMM8A, SMAC/DIABLO, MPV17, PDSS1, BCS1L, SUCLA2, C10ORF2, COX10, PLOG1and RRM2B are deafness-causing genes. A mutation in any of these deafness-causing genes will directly induce variable phenotypic HL.
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Affiliation(s)
- Ling-Feng Luo
- Institute of Cell and Developmental Biology, Zhejiang University, Hangzhou 310058, China
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24
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Kim KH, Song K, Yoon SH, Shehzad O, Kim YS, Son JH. Rescue of PINK1 protein null-specific mitochondrial complex IV deficits by ginsenoside Re activation of nitric oxide signaling. J Biol Chem 2012; 287:44109-20. [PMID: 23144451 DOI: 10.1074/jbc.m112.408146] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PINK1, linked to familial Parkinson's disease, is known to affect mitochondrial function. Here we identified a novel regulatory role of PINK1 in the maintenance of complex IV activity and characterized a novel mechanism by which NO signaling restored complex IV deficiency in PINK1 null dopaminergic neuronal cells. In PINK1 null cells, levels of specific chaperones, including Hsp60, leucine-rich pentatricopeptide repeat-containing (LRPPRC), and Hsp90, were severely decreased. LRPPRC and Hsp90 were found to act upstream of Hsp60 to regulate complex IV activity. Specifically, knockdown of Hsp60 resulted in a decrease in complex IV activity, whereas antagonistic inhibition of Hsp90 by 17-(allylamino) geldanamycin decreased both Hsp60 and complex IV activity. In contrast, overexpression of the PINK1-interacting factor LRPPRC augmented complex IV activity by up-regulating Hsp60. A similar recovery of complex IV activity was also induced by coexpression of Hsp90 and Hsp60. Drug screening identified ginsenoside Re as a compound capable of reversing the deficit in complex IV activity in PINK1 null cells through specific increases of LRPPRC, Hsp90, and Hsp60 levels. The pharmacological effects of ginsenoside Re could be reversed by treatment of the pan-NOS inhibitor L-NG-Nitroarginine Methyl Ester (L-NAME) and could also be reproduced by low-level NO treatment. These results suggest that PINK1 regulates complex IV activity via interactions with upstream regulators of Hsp60, such as LRPPRC and Hsp90. Furthermore, they demonstrate that treatment with ginsenoside Re enhances functioning of the defective PINK1-Hsp90/LRPPRC-Hsp60-complex IV signaling axis in PINK1 null neurons by restoring NO levels, providing potential for new therapeutics targeting mitochondrial dysfunction in Parkinson's disease.
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Affiliation(s)
- Kyung-Hee Kim
- Department of Brain and Cognitive Sciences, College of Pharmacy, Brain Disease Research Institute, Ewha Womans University, 120-750 Seoul, South Korea
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25
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Srinivasan S, Avadhani NG. Cytochrome c oxidase dysfunction in oxidative stress. Free Radic Biol Med 2012; 53:1252-63. [PMID: 22841758 PMCID: PMC3436951 DOI: 10.1016/j.freeradbiomed.2012.07.021] [Citation(s) in RCA: 237] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/14/2012] [Accepted: 07/17/2012] [Indexed: 12/22/2022]
Abstract
Cytochrome c oxidase (CcO) is the terminal oxidase of the mitochondrial electron transport chain. This bigenomic enzyme in mammals contains 13 subunits of which the 3 catalytic subunits are encoded by the mitochondrial genes. The remaining 10 subunits with suspected roles in the regulation, and/or assembly, are coded by the nuclear genome. The enzyme contains two heme groups (heme a and a3) and two Cu(2+) centers (Cu(2+) A and Cu(2+) B) as catalytic centers and handles more than 90% of molecular O(2) respired by the mammalian cells and tissues. CcO is a highly regulated enzyme which is believed to be the pacesetter for mitochondrial oxidative metabolism and ATP synthesis. The structure and function of the enzyme are affected in a wide variety of diseases including cancer, neurodegenerative diseases, myocardial ischemia/reperfusion, bone and skeletal diseases, and diabetes. Despite handling a high O(2) load the role of CcO in the production of reactive oxygen species still remains a subject of debate. However, a volume of evidence suggests that CcO dysfunction is invariably associated with increased mitochondrial reactive oxygen species production and cellular toxicity. In this paper we review the literature on mechanisms of multimodal regulation of CcO activity by a wide spectrum of physiological and pathological factors. We also review an array of literature on the direct or indirect roles of CcO in reactive oxygen species production.
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Affiliation(s)
- Satish Srinivasan
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104
| | - Narayan G. Avadhani
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104
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26
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Diaz F, Garcia S, Padgett KR, Moraes CT. A defect in the mitochondrial complex III, but not complex IV, triggers early ROS-dependent damage in defined brain regions. Hum Mol Genet 2012; 21:5066-77. [PMID: 22914734 DOI: 10.1093/hmg/dds350] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have created two neuron-specific mouse models of mitochondrial electron transport chain deficiencies involving defects in complex III (CIII) or complex IV (CIV). These conditional knockouts (cKOs) were created by ablation of the genes coding for the Rieske iron-sulfur protein (RISP) and COX10, respectively. RISP is one of the catalytic subunits of CIII and COX10 is an assembly factor indispensable for the maturation of Cox1, one of the catalytic subunits of CIV. Although the rates of gene deletion, protein loss and complex dysfunction were similar, the RISP cKO survived 3.5 months of age, whereas the COX10 cKO survived for 10-12 months. The RISP cKO had a sudden death, with minimal behavioral changes. In contrast, the COX10 cKO showed a distinctive behavioral phenotype with onset at 4 months of age followed by a slower but progressive neurodegeneration. Curiously, the piriform and somatosensory cortices were more vulnerable to the CIII defect whereas cingulate cortex and to a less extent piriform cortex were affected preferentially by the CIV defect. In addition, the CIII model showed severe and early reactive oxygen species damage, a feature not observed until very late in the pathology of the CIV model. These findings illustrate how specific respiratory chain defects have distinct molecular mechanisms, leading to distinct pathologies, akin to the clinical heterogeneity observed in patients with mitochondrial diseases.
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Affiliation(s)
- Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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27
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Adaptation of respiratory chain biogenesis to cytochrome c oxidase deficiency caused by SURF1 gene mutations. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1114-24. [PMID: 22465034 DOI: 10.1016/j.bbadis.2012.03.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 03/09/2012] [Accepted: 03/12/2012] [Indexed: 01/26/2023]
Abstract
The loss of Surf1 protein leads to a severe COX deficiency manifested as a fatal neurodegenerative disorder, the Leigh syndrome (LS(COX)). Surf1 appears to be involved in the early step of COX assembly but its function remains unknown. The aim of the study was to find out how SURF1 gene mutations influence expression of OXPHOS and other pro-mitochondrial genes and to further characterize the altered COX assembly. Analysis of fibroblast cell lines from 9 patients with SURF1 mutations revealed a 70% decrease of the COX complex content to be associated with 32-54% upregulation of respiratory chain complexes I, III and V and accumulation of Cox5a subunit. Whole genome expression profiling showed a general decrease of transcriptional activity in LS(COX) cells and indicated that the adaptive changes in OXPHOS complexes are due to a posttranscriptional compensatory mechanism. Electrophoretic and WB analysis showed that in mitochondria of LS(COX) cells compared to controls, the assembled COX is present entirely in a supercomplex form, as I-III₂-IV supercomplex but not as larger supercomplexes. The lack of COX also caused an accumulation of I-III₂ supercomplex. The accumulated Cox5a was mainly present as a free subunit. We have found out that the major COX assembly subcomplexes accumulated due to SURF1 mutations range in size between approximately 85-140kDa. In addition to the originally proposed S2 intermediate they might also represent Cox1-containing complexes lacking other COX subunits. Unlike the assembled COX, subcomplexes are unable to associate with complexes I and III.
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Abstract
Mitochondrial diseases involve the dysfunction of the oxidative phosphorylation (OXPHOS) system. This group of diseases presents with heterogeneous clinical symptoms affecting mainly organs with high energy demands. Defects in the multimeric complexes comprising the OXPHOS system have a dual genetic origin, mitochondrial or nuclear DNA. Although many nuclear DNA mutations involve genes coding for subunits of the respiratory complexes, the majority of mutations found to date affect factors that do not form part of the final complexes. These assembly factors or chaperones have multiple functions ranging from cofactor insertion to proper assembly/stability of the complexes. Although significant progress has been made in the last few years in the discovery of new assembly factors, the function of many remains elusive. Here, we describe assembly factors or chaperones that are required for respiratory chain complex assembly and their clinical relevance.
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Ugalde C, Morán M, Blázquez A, Arenas J, Martín MA. Mitochondrial Disorders Due to Nuclear OXPHOS Gene Defects. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 652:85-116. [DOI: 10.1007/978-90-481-2813-6_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Diaz F. Cytochrome c oxidase deficiency: patients and animal models. Biochim Biophys Acta Mol Basis Dis 2009; 1802:100-10. [PMID: 19682572 DOI: 10.1016/j.bbadis.2009.07.013] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 12/17/2022]
Abstract
Cytochrome c oxidase (COX) deficiencies are one of the most common defects of the respiratory chain found in mitochondrial diseases. COX is a multimeric inner mitochondrial membrane enzyme formed by subunits encoded by both the nuclear and the mitochondrial genome. COX biosynthesis requires numerous assembly factors that do not form part of the final complex but participate in prosthetic group synthesis and metal delivery in addition to membrane insertion and maturation of COX subunits. Human diseases associated with COX deficiency including encephalomyopathies, Leigh syndrome, hypertrophic cardiomyopathies, and fatal lactic acidosis are caused by mutations in COX subunits or assembly factors. In the last decade, numerous animal models have been created to understand the pathophysiology of COX deficiencies and the function of assembly factors. These animal models, ranging from invertebrates to mammals, in most cases mimic the pathological features of the human diseases.
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Affiliation(s)
- Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, Florida 33136, USA.
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Torraco A, Diaz F, Vempati UD, Moraes CT. Mouse models of oxidative phosphorylation defects: powerful tools to study the pathobiology of mitochondrial diseases. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1793:171-80. [PMID: 18601959 PMCID: PMC2652735 DOI: 10.1016/j.bbamcr.2008.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 05/28/2008] [Accepted: 06/04/2008] [Indexed: 01/14/2023]
Abstract
Defects in the oxidative phosphorylation system (OXPHOS) are responsible for a group of extremely heterogeneous and pleiotropic pathologies commonly known as mitochondrial diseases. Although many mutations have been found to be responsible for OXPHOS defects, their pathogenetic mechanisms are still poorly understood. An important contribution to investigate the in vivo function of several mitochondrial proteins and their role in mitochondrial dysfunction, has been provided by mouse models. Thanks to their genetic and physiologic similarity to humans, mouse models represent a powerful tool to investigate the impact of pathological mutations on metabolic pathways. In this review we discuss the main mouse models of mitochondrial disease developed, focusing on the ones that directly affect the OXPHOS system.
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Affiliation(s)
- Alessandra Torraco
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Uma D. Vempati
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
- Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
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Assembly of the oxidative phosphorylation system in humans: what we have learned by studying its defects. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:200-11. [PMID: 18620006 DOI: 10.1016/j.bbamcr.2008.05.028] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 05/12/2008] [Accepted: 05/17/2008] [Indexed: 02/07/2023]
Abstract
Assembly of the oxidative phosphorylation (OXPHOS) system in the mitochondrial inner membrane is an intricate process in which many factors must interact. The OXPHOS system is composed of four respiratory chain complexes, which are responsible for electron transport and generation of the proton gradient in the mitochondrial intermembrane space, and of the ATP synthase that uses this proton gradient to produce ATP. Mitochondrial human disorders are caused by dysfunction of the OXPHOS system, and many of them are associated with altered assembly of one or more components of the OXPHOS system. The study of assembly defects in patients has been useful in unraveling and/or gaining a complete understanding of the processes by which these large multimeric complexes are formed. We review here current knowledge of the biogenesis of OXPHOS complexes based on investigation of the corresponding disorders.
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Oldfors A, Tulinius M. Mitochondrial encephalomyopathies. HANDBOOK OF CLINICAL NEUROLOGY 2007; 86:125-165. [PMID: 18808998 DOI: 10.1016/s0072-9752(07)86006-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Abstract
Defects of mitochondrial metabolism cause a wide range of human diseases that include examples from all medical subspecialties. This review updates the topic of mitochondrial diseases by reviewing the most important recent advances in this area. The factors influencing inheritance, maintenance and replication of mtDNA are reviewed and the genotype-phenotype of mtDNA disorders has been expanded, with new insights into epidemiology, pathogenesis and its role in ageing. Recently identified nuclear gene mutations of mitochondrial proteins include mutations of frataxin causing Friedreich's ataxia, PINK1, DJ1 causing Parkinson's disease and POLG causing infantile mtDNA depletion syndrome, ophthalmoplegia, parkinsonism, male subfertility and, in a transgenic mouse model, premature senescence. Mitochondrial defects in neurodegenerative diseases include Parkinson's, Alzheimer's and Huntington's disease. Improved understanding of mtDNA inheritance and mutation penetrance patterns, and novel techniques for mtDNA modification offer significant prospects for more accurate genetic counselling and effective future therapies.
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Affiliation(s)
- Anthony H V Schapira
- University Department of Clinical Neurosciences, Royal Free and University College Medical School, and Institute of Neurology, University College London, London NW3 2PF, UK.
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Diaz F, Fukui H, Garcia S, Moraes CT. Cytochrome c oxidase is required for the assembly/stability of respiratory complex I in mouse fibroblasts. Mol Cell Biol 2006; 26:4872-81. [PMID: 16782876 PMCID: PMC1489173 DOI: 10.1128/mcb.01767-05] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 10/30/2005] [Accepted: 04/18/2006] [Indexed: 11/20/2022] Open
Abstract
Cytochrome c oxidase (COX) biogenesis requires COX10, which encodes a protoheme:heme O farnesyl transferase that participates in the biosynthesis of heme a. We created COX10 knockout mouse cells that lacked cytochrome aa3, were respiratory deficient, had no detectable complex IV activity, and were unable to assemble COX. Unexpectedly, the levels of respiratory complex I were markedly reduced in COX10 knockout clones. Pharmacological inhibition of COX did not affect the levels of complex I, and transduction of knockout cells with lentivirus expressing wild-type or mutant COX10 (retaining residual activity) restored complex I to normal levels. Pulse-chase experiments could not detect newly assembled complex I, suggesting that either COX is required for assembly of complex I or the latter is quickly degraded. These results suggest that in rapidly dividing cells, complex IV is required for complex I assembly or stability.
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Affiliation(s)
- Francisca Diaz
- Department of Neurology, University of Miami School of Medicine, 1095 NW 14 Terrace, Miami, FL 33136, USA
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Coenen MJH, Smeitink JAM, Pots JM, van Kaauwen E, Trijbels FJM, Hol FA, van den Heuvel LP. Sequence analysis of the structural nuclear encoded subunits and assembly genes of cytochrome c oxidase in a cohort of 10 isolated complex IV-deficient patients revealed five mutations. J Child Neurol 2006; 21:508-11. [PMID: 16948936 DOI: 10.1177/08830738060210062501] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The mitochondrial oxidative phosphorylation system is composed of five multiprotein complexes. The fourth complex of this system, cytochrome c oxidase (complex IV), consists of 13 subunits: 3 encoded by mitochondrial DNA and 10 encoded by the nuclear genome. Patients with an isolated complex IV deficiency frequently harbor mutations in nuclear genes encoding for proteins necessary for the assembly of the complex. Strikingly, until now, no mutations have been detected in the nuclear encoded structural subunits of complex IV in these patients. We report the results of a mutational analysis study in patients with isolated complex IV deficiency screened for mutations in all structural genes as well as assembly genes known to cause complex IV deficiency. Four patients carried mutations in the complex IV assembly gene SURF1. One patient harbored a mutation in the COX10 gene involved in heme A synthesis. Mutations in the 10 nuclear encoded structural genes were not present.
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Affiliation(s)
- Marieke J H Coenen
- Department of Paediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, the Netherlands
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Diaz F, Thomas CK, Garcia S, Hernandez D, Moraes CT. Mice lacking COX10 in skeletal muscle recapitulate the phenotype of progressive mitochondrial myopathies associated with cytochrome c oxidase deficiency. Hum Mol Genet 2005; 14:2737-48. [PMID: 16103131 PMCID: PMC2778476 DOI: 10.1093/hmg/ddi307] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have created a mouse model with an isolated cytochrome c oxidase (COX) deficiency by disrupting the COX10 gene in skeletal muscle. Missense mutations in COX10 have been previously associated with mitochondrial disorders. Cox10p is a protoheme:heme-O-farnesyl transferase required for the synthesis of heme a, the prosthetic group of the catalytic center of COX. COX10 conditional knockout mice were generated by crossing a LoxP-tagged COX10 mouse with a transgenic mouse expressing cre recombinase under the myosin light chain 1f promoter. The COX10 knockout mice were healthy until approximately 3 months of age when they started developing a slowly progressive myopathy. Surprisingly, even though COX activity in COX10 KO muscles was <5% of control muscle at 2.5 months, these muscles were still able to contract at 80-100% of control maximal forces and showed only a 10% increase in fatigability, and no signs of oxidative damage or apoptosis were detected. However, the myopathy worsened with time, particularly in female animals. This COX10 KO mouse allowed us to correlate the muscle function with residual COX activity, an estimate that can help predict the progression pattern of human mitochondrial myopathies.
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Affiliation(s)
- Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Christine K. Thomas
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Sofia Garcia
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Dayami Hernandez
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Carlos T. Moraes
- Department of Neurology, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
- Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, 1095 NW 14th Terrace, Miami, FL 33136, USA
- To whom correspondence should be addressed. Tel: +1 3052435858; Fax: +1 3052433914.
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