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Bernardino Gomes TM, Vincent AE, Menger KE, Stewart JB, Nicholls TJ. Mechanisms and pathologies of human mitochondrial DNA replication and deletion formation. Biochem J 2024; 481:683-715. [PMID: 38804971 DOI: 10.1042/bcj20230262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Human mitochondria possess a multi-copy circular genome, mitochondrial DNA (mtDNA), that is essential for cellular energy metabolism. The number of copies of mtDNA per cell, and their integrity, are maintained by nuclear-encoded mtDNA replication and repair machineries. Aberrant mtDNA replication and mtDNA breakage are believed to cause deletions within mtDNA. The genomic location and breakpoint sequences of these deletions show similar patterns across various inherited and acquired diseases, and are also observed during normal ageing, suggesting a common mechanism of deletion formation. However, an ongoing debate over the mechanism by which mtDNA replicates has made it difficult to develop clear and testable models for how mtDNA rearrangements arise and propagate at a molecular and cellular level. These deletions may impair energy metabolism if present in a high proportion of the mtDNA copies within the cell, and can be seen in primary mitochondrial diseases, either in sporadic cases or caused by autosomal variants in nuclear-encoded mtDNA maintenance genes. These mitochondrial diseases have diverse genetic causes and multiple modes of inheritance, and show notoriously broad clinical heterogeneity with complex tissue specificities, which further makes establishing genotype-phenotype relationships challenging. In this review, we aim to cover our current understanding of how the human mitochondrial genome is replicated, the mechanisms by which mtDNA replication and repair can lead to mtDNA instability in the form of large-scale rearrangements, how rearranged mtDNAs subsequently accumulate within cells, and the pathological consequences when this occurs.
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Affiliation(s)
- Tiago M Bernardino Gomes
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- NHS England Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne NE2 4HH, U.K
| | - Amy E Vincent
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Katja E Menger
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - James B Stewart
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
| | - Thomas J Nicholls
- Wellcome Centre for Mitochondrial Research, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K
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2
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Mathis D, Koch J, Koller S, Sauter K, Flück C, Uldry AC, Forny P, Froese DS, Laemmle A. Induced pluripotent stem cell-derived hepatocytes reveal TCA cycle disruption and the potential basis for triheptanoin treatment for malate dehydrogenase 2 deficiency. Mol Genet Metab Rep 2024; 39:101066. [PMID: 38425868 PMCID: PMC10900122 DOI: 10.1016/j.ymgmr.2024.101066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024] Open
Abstract
Mitochondrial malate dehydrogenase 2 (MDH2) is crucial to cellular energy generation through direct participation in the tricarboxylic acid (TCA) cycle and the malate aspartate shuttle (MAS). Inherited MDH2 deficiency is an ultra-rare metabolic disease caused by bi-allelic pathogenic variants in the MDH2 gene, resulting in early-onset encephalopathy, psychomotor delay, muscular hypotonia and frequent seizures. Currently, there is no cure for this devastating disease. We recently reported symptomatic improvement of a three-year-old girl with MDH2 deficiency following treatment with the triglyceride triheptanoin. Here, we aimed to better characterize this disease and improve our understanding of the potential utility of triheptanoin treatment. Using fibroblasts derived from this patient, we generated induced pluripotent stem cells (hiPSCs) and differentiated them into hepatocytes (hiPSC-Heps). Characterization of patient-derived hiPSCs and hiPSC-Heps revealed significantly reduced MDH2 protein expression. Untargeted proteotyping of hiPSC-Heps revealed global dysregulation of mitochondrial proteins, including upregulation of TCA cycle and fatty acid oxidation enzymes. Metabolomic profiling confirmed TCA cycle and MAS dysregulation, and demonstrated normalization of malate, fumarate and aspartate following treatment with the triheptanoin components glycerol and heptanoate. Taken together, our results provide the first patient-derived hiPSC-Hep-based model of MDH2 deficiency, confirm altered TCA cycle function, and provide further evidence for the implementation of triheptanoin therapy for this ultra-rare disease. Synopsis This study reveals altered expression of mitochondrial pathways including the tricarboxylic acid cycle and changes in metabolite profiles in malate dehydrogenase 2 deficiency and provides the molecular basis for triheptanoin treatment in this ultra-rare disease.
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Affiliation(s)
- Déborah Mathis
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Jasmine Koch
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Sophie Koller
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Switzerland
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Pharmacy, Medical Faculty, University of Bern, Bern, Switzerland
| | - Kay Sauter
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Christa Flück
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Patrick Forny
- Division of Metabolism and Children's Research Center, University Children's Hospital, University of Zurich, Zurich, Switzerland
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA
| | - D. Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital, University of Zurich, Zurich, Switzerland
| | - Alexander Laemmle
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Switzerland
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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3
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Yan W, Xie C, Sun S, Zheng Q, Wang J, Wang Z, Man CH, Wang H, Yang Y, Wang T, Shi L, Zhang S, Huang C, Xu S, Wang YP. SUCLG1 restricts POLRMT succinylation to enhance mitochondrial biogenesis and leukemia progression. EMBO J 2024; 43:2337-2367. [PMID: 38649537 PMCID: PMC11183053 DOI: 10.1038/s44318-024-00101-9] [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: 09/27/2023] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/25/2024] Open
Abstract
Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.
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Affiliation(s)
- Weiwei Yan
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Chengmei Xie
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Sijun Sun
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Quan Zheng
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jingyi Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Zihao Wang
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China
| | - Cheuk-Him Man
- Division of Haematology, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Haiyan Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Yunfan Yang
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 250012, Jinan, China
| | - Tianshi Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Leilei Shi
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Shengjie Zhang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Chen Huang
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Shuangnian Xu
- Department of Hematology, Southwest Hospital, Army Medical University, 400038, Chongqing, China.
| | - Yi-Ping Wang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China.
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Yu H, Wang F, Wu J, Gong J, Bi S, Mao Y, Jia D, Chai G. Integrated transcriptomics reveals the brain and blood biomarkers in Alzheimer's disease. CNS Neurosci Ther 2023; 29:3943-3951. [PMID: 37334737 PMCID: PMC10651972 DOI: 10.1111/cns.14316] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/20/2023] Open
Abstract
BACKGROUND The systematic molecular associations between the peripheral blood cells and brain in Alzheimer's disease (AD) remains unclear, which hinders our understanding of AD pathological mechanisms and the exploration of new diagnostic biomarkers. METHODS Here, we performed an integrated analysis of the brain and peripheral blood cells transcriptomics to establish peripheral biomarkers of AD. By employing multiple statistical analyses plus machine learning, we identified and validated multiple regulated central and peripheral network in patients with AD. RESULTS By bioinformatics analysis, a total of 243 genes were differentially expressed in the central and peripheral systems, mainly enriched in three modules: immune response, glucose metabolism and lysosome. In addition, lysosome related gene ATP6V1E1 and immune response related genes (IL2RG, OSM, EVI2B TNFRSF1A, CXCR4, STAT5A) were significantly correlated with Aβ or Tau pathology. Finally, receiver operating characteristic (ROC) analysis revealed that ATP6V1E1 showed high-diagnostic potential for AD. CONCLUSION Taken together, our data identified the main pathological pathways in AD progression, particularly the systemic dysregulation of the immune response, and provided peripheral biomarkers for AD diagnosis.
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Affiliation(s)
- Haitao Yu
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
| | - Fangzhou Wang
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
| | - Jia‐jun Wu
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
| | - Juan Gong
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
| | - Shuguang Bi
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
| | - Yumin Mao
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
| | - Dongdong Jia
- The Affiliated Mental Health Center of Jiangnan UniversityWuxi Central Rehabilitation HospitalWuxiChina
| | - Gao‐shang Chai
- Department of Fundamental Medicine, Wuxi School of MedicineJiangnan UniversityWuxiChina
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Lancaster MS, Kim B, Doud EH, Tate MD, Sharify AD, Gao H, Chen D, Simpson E, Gillespie P, Chu X, Miller MJ, Wang Y, Liu Y, Mosley AL, Kim J, Graham BH. Loss of succinyl-CoA synthetase in mouse forebrain results in hypersuccinylation with perturbed neuronal transcription and metabolism. Cell Rep 2023; 42:113241. [PMID: 37819759 PMCID: PMC10683835 DOI: 10.1016/j.celrep.2023.113241] [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: 08/08/2022] [Revised: 08/24/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023] Open
Abstract
Lysine succinylation is a subtype of protein acylation associated with metabolic regulation of succinyl-CoA in the tricarboxylic acid cycle. Deficiency of succinyl-CoA synthetase (SCS), the tricarboxylic acid cycle enzyme catalyzing the interconversion of succinyl-CoA to succinate, results in mitochondrial encephalomyopathy in humans. This report presents a conditional forebrain-specific knockout (KO) mouse model of Sucla2, the gene encoding the ATP-specific beta isoform of SCS, resulting in postnatal deficiency of the entire SCS complex. Results demonstrate that accumulation of succinyl-CoA in the absence of SCS leads to hypersuccinylation within the murine cerebral cortex. Specifically, increased succinylation is associated with functionally significant reduced activity of respiratory chain complex I and widescale alterations in chromatin landscape and gene expression. Integrative analysis of the transcriptomic data also reveals perturbations in regulatory networks of neuronal transcription in the KO forebrain. Together, these findings provide evidence that protein succinylation plays a significant role in the pathogenesis of SCS deficiency.
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Affiliation(s)
- Makayla S Lancaster
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Byungwook Kim
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Emma H Doud
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Mason D Tate
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ahmad D Sharify
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Hongyu Gao
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Duojiao Chen
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ed Simpson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Patrick Gillespie
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Xiaona Chu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Marcus J Miller
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yue Wang
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yunlong Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Jungsu Kim
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Brett H Graham
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Kim YR, Sang MK. Effects of di-(2-ethylhexyl) phthalate on growth, metabolism, and virulence of the plant pathogenic bacterium Acidovorax citrulli. Front Cell Infect Microbiol 2023; 13:1228713. [PMID: 37692166 PMCID: PMC10485622 DOI: 10.3389/fcimb.2023.1228713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 08/07/2023] [Indexed: 09/12/2023] Open
Abstract
Acidovorax citrulli is a seed-borne bacterial pathogen that causes bacterial fruit blotch in cucurbits and severely affects the production of cucumbers and watermelons globally. In this study, we investigated the effects of di-(2-ethylhexyl) phthalate (DEHP) on the growth, metabolism, and virulence of A. citrulli. Bacterial population was not affected by DEHP exposure; moreover, significant changes were not observed in lipid peroxidation, membrane permeability, and nucleic acid leakage. However, palmitoleic acid content was increased in the cell membrane of DEHP-exposed A. citrulli. Further, DEHP exposure increased the activity of TCA cycle-related enzymes, including α-ketoglutarate dehydrogenase and succinyl-CoA synthetase, along with increase in the content of glutamate, succinate, fumarate, and malate in TCA cycle. Additionally, total 270 genes were differentially expressed by the treatment, of which 28 genes were upregulated and 242 genes, including those related to translation, flagellum-dependent cell motility, and flagellum assembly, were downregulated. Regarding virulence traits, swimming activity was decreased in DEHP-exposed A. citrulli; however, biofilm formation was not affected in in vitro assay. Moreover, relative expression of pathogenicity genes, including hrpX and hrpG, were decreased in DEHP-exposed A. citrulli compared to that of unexposed A. citrulli. Therefore, these results suggest that DEHP accumulation in soil could potentially influence the metabolism and virulence traits of A. citrulli.
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Affiliation(s)
| | - Mee Kyung Sang
- Division of Agricultural Microbiology, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea
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7
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Lancaster MS, Graham BH. Succinyl-CoA Synthetase Dysfunction as a Mechanism of Mitochondrial Encephalomyopathy: More than Just an Oxidative Energy Deficit. Int J Mol Sci 2023; 24:10725. [PMID: 37445899 PMCID: PMC10342173 DOI: 10.3390/ijms241310725] [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: 05/12/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Biallelic pathogenic variants in subunits of succinyl-CoA synthetase (SCS), a tricarboxylic acid (TCA) cycle enzyme, are associated with mitochondrial encephalomyopathy in humans. SCS catalyzes the interconversion of succinyl-CoA to succinate, coupled to substrate-level phosphorylation of either ADP or GDP, within the TCA cycle. SCS-deficient encephalomyopathy typically presents in infancy and early childhood, with many patients succumbing to the disease during childhood. Common symptoms include abnormal brain MRI, basal ganglia lesions and cerebral atrophy, severe hypotonia, dystonia, progressive psychomotor regression, and growth deficits. Although subunits of SCS were first identified as causal genes for progressive metabolic encephalomyopathy in the early 2000s, recent investigations are now beginning to unravel the pathomechanisms underlying this metabolic disorder. This article reviews the current understanding of SCS function within and outside the TCA cycle as it relates to the complex and multifactorial mechanisms underlying SCS-related mitochondrial encephalomyopathy.
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Affiliation(s)
| | - Brett H. Graham
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, 975 W. Walnut St., Room IB257, Indianapolis, IN 46202, USA;
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8
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Abstract
Mitochondrial dysfunction, especially perturbation of oxidative phosphorylation and adenosine triphosphate (ATP) generation, disrupts cellular homeostasis and is a surprisingly frequent cause of central and peripheral nervous system pathology. Mitochondrial disease is an umbrella term that encompasses a host of clinical syndromes and features caused by in excess of 300 different genetic defects affecting the mitochondrial and nuclear genomes. Patients with mitochondrial disease can present at any age, ranging from neonatal onset to late adult life, with variable organ involvement and neurological manifestations including neurodevelopmental delay, seizures, stroke-like episodes, movement disorders, optic neuropathy, myopathy, and neuropathy. Until relatively recently, analysis of skeletal muscle biopsy was the focus of diagnostic algorithms, but step-changes in the scope and availability of next-generation sequencing technology and multiomics analysis have revolutionized mitochondrial disease diagnosis. Currently, there is no specific therapy for most types of mitochondrial disease, although clinical trials research in the field is gathering momentum. In that context, active management of epilepsy, stroke-like episodes, dystonia, brainstem dysfunction, and Parkinsonism are all the more important in improving patient quality of life and reducing mortality.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.
| | - Robert McFarland
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
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9
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Lopriore P, Gomes F, Montano V, Siciliano G, Mancuso M. Mitochondrial Epilepsy, a Challenge for Neurologists. Int J Mol Sci 2022; 23:ijms232113216. [PMID: 36362003 PMCID: PMC9656379 DOI: 10.3390/ijms232113216] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 01/29/2023] Open
Abstract
Primary mitochondrial diseases are relatively common inborn errors of energy metabolism, with a combined prevalence of 1 in 4300. These disorders typically affect tissues with high energy requirements, including the brain. Epilepsy affects >1% of the worldwide population, making it one of the most common neurological illnesses; it may be the presenting feature of a mitochondrial disease, but is often part of a multisystem clinical presentation. The major genetic causes of mitochondrial epilepsy are mutations in mitochondrial DNA and in the nuclear-encoded gene POLG. Treatment of mitochondrial epilepsy may be challenging, often representing a poor prognostic feature. This narrative review will cover the most recent advances in the field of mitochondrial epilepsy, from pathophysiology and genetic etiologies to phenotype and treatment options.
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Affiliation(s)
- Piervito Lopriore
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Fábio Gomes
- Neurology Department, Coimbra University Hospital Centre, 3004-561 Coimbra, Portugal
| | - Vincenzo Montano
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Gabriele Siciliano
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Michelangelo Mancuso
- Neurological Institute, Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
- Correspondence:
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10
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Shintaku J, Pernice WM, Eyaid W, Gc JB, Brown ZP, Juanola-Falgarona M, Torres-Torronteras J, Sommerville EW, Hellebrekers DM, Blakely EL, Donaldson A, van de Laar IM, Leu CS, Marti R, Frank J, Tanji K, Koolen DA, Rodenburg RJ, Chinnery PF, Smeets HJM, Gorman GS, Bonnen PE, Taylor RW, Hirano M. RRM1 variants cause a mitochondrial DNA maintenance disorder via impaired de novo nucleotide synthesis. J Clin Invest 2022; 132:145660. [PMID: 35617047 PMCID: PMC9246377 DOI: 10.1172/jci145660] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 05/19/2022] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial DNA (mtDNA) depletion/deletions syndromes (MDDS) encompass a clinically and etiologically heterogenous group of mitochondrial disorders due to impaired mtDNA maintenance. Among the most frequent causes of MDDS are defects in nucleoside/nucleotide metabolism, which is critical for synthesis and homeostasis of the deoxynucleoside triphosphate (dNTP) substrates of mtDNA replication. A central enzyme for generating dNTPs is ribonucleotide reductase, a critical mediator of de novo nucleotide synthesis composed of catalytic RRM1 subunits in complex with RRM2 or p53R2. Here, we report five probands from four families who presented with ptosis and ophthalmoplegia, plus other manifestations and multiple mtDNA deletions in muscle. We identified three RRM1 loss-of-function variants, including a dominant catalytic site variant (NP_001024.1: p.N427K) and two homozygous recessive variants at p.R381, which has evolutionarily conserved interactions with the specificity site. Atomistic molecular dynamics simulations indicate mechanisms by which RRM1 variants affect protein structure. Cultured primary skin fibroblasts of probands manifested mtDNA depletion under cycling conditions, indicating impaired de novo nucleotide synthesis. Fibroblasts also exhibited aberrant nucleoside diphosphate and dNTP pools and mtDNA ribonucleotide incorporation. Our data reveal primary RRM1 deficiency and, by extension, impaired de novo nucleotide synthesis are causes of MDDS.
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Affiliation(s)
- Jonathan Shintaku
- Department of Neurology, Columbia University Irving Medical Center, New York, United States of America
| | - Wolfgang M Pernice
- Department of Neurology, Columbia University Irving Medical Center, New York, United States of America
| | - Wafaa Eyaid
- Department of Pediatrics, King Saud bin Abdulaziz University for Health Science, Riyadh, Saudi Arabia
| | - Jeevan B Gc
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States of America
| | - Zuben P Brown
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States of America
| | - Marti Juanola-Falgarona
- Department of Neurology, Columbia University Irving Medical Center, New York, United States of America
| | | | - Ewen W Sommerville
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle, United Kingdom
| | - Debby Mei Hellebrekers
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, Netherlands
| | - Emma L Blakely
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle, United Kingdom
| | - Alan Donaldson
- Clinical Genetics Department, University of Bristol, Bristol, United Kingdom
| | - Ingrid Mbh van de Laar
- Department of Clinical Genetics, Erasmus Medical Center Rotterdam, Rotterdam, Netherlands
| | - Cheng-Shiun Leu
- Biostatistics, Columbia University, New York, United States of America
| | - Ramon Marti
- Laboratori de patologia neuromuscular i mitocondrial, Vall d'Hebron Research Institute, Barcelona, Spain
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, United States of America
| | - Kurenai Tanji
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, United States of America
| | - David A Koolen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Richard J Rodenburg
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Patrick F Chinnery
- Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - H J M Smeets
- University of Maastricht, Maastricht, Netherlands
| | - Gráinne S Gorman
- Wellcome Trust Centre for Mitochondrial Research, Newcastle University, Newcastle, United Kingdom
| | - Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States of America
| | | | - Michio Hirano
- Department of Neurology, Columbia University Irving Medical Center, New York, United States of America
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11
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232nd ENMC International Workshop: Recommendations for treatment of mitochondrial DNA maintenance disorders. 16 – 18 June 2017, Heemskerk, The Netherlands. Neuromuscul Disord 2022; 32:609-620. [DOI: 10.1016/j.nmd.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/24/2022]
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12
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Complex hereditary peripheral neuropathies caused by novel variants in mitochondrial-related nuclear genes. J Neurol 2022; 269:4129-4140. [PMID: 35235001 PMCID: PMC9293870 DOI: 10.1007/s00415-022-11026-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/05/2022] [Accepted: 02/11/2022] [Indexed: 11/04/2022]
Abstract
Mitochondrial disorders are a group of clinically and genetically heterogeneous multisystem disorders and peripheral neuropathy is frequently described in the context of mutations in mitochondrial-related nuclear genes. This study aimed to identify the causative mutations in mitochondrial-related nuclear genes in suspected hereditary peripheral neuropathy patients. We enrolled a large Japanese cohort of clinically suspected hereditary peripheral neuropathy patients who were mutation negative in the prescreening of the known Charcot–Marie–Tooth disease-causing genes. We performed whole-exome sequencing on 247 patients with autosomal recessive or sporadic inheritance for further analysis of 167 mitochondrial-related nuclear genes. We detected novel bi-allelic likely pathogenic/pathogenic variants in four patients, from four mitochondrial-related nuclear genes: pyruvate dehydrogenase beta-polypeptide (PDHB), mitochondrial poly(A) polymerase (MTPAP), hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase, beta subunit (HADHB), and succinate-CoA ligase ADP-forming beta subunit (SUCLA2). All these patients showed sensory and motor axonal polyneuropathy, combined with central nervous system or multisystem involvements. The pathological analysis of skeletal muscles revealed mild neurogenic changes without significant mitochondrial abnormalities. Targeted screening of mitochondria-related nuclear genes should be considered for patients with complex hereditary axonal polyneuropathy, accompanied by central nervous system dysfunctions, or with unexplainable multisystem disorders.
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13
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Mitochondrial Neurodegeneration. Cells 2022; 11:cells11040637. [PMID: 35203288 PMCID: PMC8870525 DOI: 10.3390/cells11040637] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 01/28/2022] [Accepted: 02/06/2022] [Indexed: 01/27/2023] Open
Abstract
Mitochondria are cytoplasmic organelles, which generate energy as heat and ATP, the universal energy currency of the cell. This process is carried out by coupling electron stripping through oxidation of nutrient substrates with the formation of a proton-based electrochemical gradient across the inner mitochondrial membrane. Controlled dissipation of the gradient can lead to production of heat as well as ATP, via ADP phosphorylation. This process is known as oxidative phosphorylation, and is carried out by four multiheteromeric complexes (from I to IV) of the mitochondrial respiratory chain, carrying out the electron flow whose energy is stored as a proton-based electrochemical gradient. This gradient sustains a second reaction, operated by the mitochondrial ATP synthase, or complex V, which condensates ADP and Pi into ATP. Four complexes (CI, CIII, CIV, and CV) are composed of proteins encoded by genes present in two separate compartments: the nuclear genome and a small circular DNA found in mitochondria themselves, and are termed mitochondrial DNA (mtDNA). Mutations striking either genome can lead to mitochondrial impairment, determining infantile, childhood or adult neurodegeneration. Mitochondrial disorders are complex neurological syndromes, and are often part of a multisystem disorder. In this paper, we divide the diseases into those caused by mtDNA defects and those that are due to mutations involving nuclear genes; from a clinical point of view, we discuss pediatric disorders in comparison to juvenile or adult-onset conditions. The complementary genetic contributions controlling organellar function and the complexity of the biochemical pathways present in the mitochondria justify the extreme genetic and phenotypic heterogeneity of this new area of inborn errors of metabolism known as ‘mitochondrial medicine’.
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14
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Hadrava Vanova K, Pang Y, Krobova L, Kraus M, Nahacka Z, Boukalova S, Pack SD, Zobalova R, Zhu J, Huynh TT, Jochmanova I, Uher O, Hubackova S, Dvorakova S, Garrett TJ, Ghayee HK, Wu X, Schuster B, Knapp PE, Frysak Z, Hartmann I, Nilubol N, Cerny J, Taieb D, Rohlena J, Neuzil J, Yang C, Pacak K. Germline SUCLG2 Variants in Patients with Pheochromocytoma and Paraganglioma. J Natl Cancer Inst 2021; 114:130-138. [PMID: 34415331 DOI: 10.1093/jnci/djab158] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/14/2020] [Accepted: 08/18/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Pheochromocytoma and paraganglioma (PPGL) are neuroendocrine tumors with frequent mutations in genes linked to the tricarboxylic acid cycle. However, no pathogenic variant has been found to date in succinyl-CoA ligase (SUCL), an enzyme that provides substrate for succinate dehydrogenase (SDH; mitochondrial complex II; CII), a known tumor suppressor in PPGL. METHODS A cohort of 352 subjects with apparently sporadic PPGL underwent genetic testing using a panel of 54 genes developed at the National Institutes of Health, including the SUCLG2 subunit of SUCL. Gene deletion, succinate levels, and protein levels were assessed in tumors where possible. To confirm the possible mechanism, we used a progenitor cell line, hPheo1, derived from a human pheochromocytoma, and ablated and re-expressed SUCLG2. RESULTS We describe eight germline variants in the GTP-binding domain of SUCLG2 in 15 patients (15 of 352, 4.3%) with apparently sporadic PPGL. Analysis of SUCLG2-mutated tumors and SUCLG2-deficient hPheo1 cells revealed absence of SUCLG2 protein, decrease in the level of the SDHB subunit of CII and faulty assembly of the complex, resulting in aberrant respiration and elevated succinate accumulation. CONCLUSIONS Our study suggests SUCLG2 as a novel candidate gene in the genetic landscape of PPGL. Large-scale sequencing may uncover additional cases harboring SUCLG2 variants and provide more detailed information about their prevalence and penetrance.
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Affiliation(s)
- Katerina Hadrava Vanova
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Ying Pang
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Linda Krobova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Michal Kraus
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Zuzana Nahacka
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Stepana Boukalova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Svetlana D Pack
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Renata Zobalova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Jun Zhu
- Systems Biology Center, National Heart Lung Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Thanh-Truc Huynh
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Ivana Jochmanova
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,1st Department of Internal Medicine, Pavol Jozef Safarik University in Kosice, Faculty of Medicine and Teaching Hospital of Louis Pasteur, Kosice, Slovakia
| | - Ondrej Uher
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Department of Medical Biology, Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Sona Hubackova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Sarka Dvorakova
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Timothy J Garrett
- Southeast Center for Integrated Metabolomics, Clinical and Translational Science Institute, University of Florida, Gainesville, FL, USA
| | - Hans K Ghayee
- Department of Medicine, Division of Endocrinology, Malcom Randall VA Medical Center, University of Florida, Gainesville, FL, USA
| | - Xiaolin Wu
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Bjoern Schuster
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Philip E Knapp
- Section of Endocrinology, Boston Medical Center, Boston University, Boston, MA, USA
| | - Zdenek Frysak
- 3rd Department of Internal Medicine, University Hospital and Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Igor Hartmann
- Department of Urology, University Hospital Olomouc and Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Naris Nilubol
- Endocrine Surgery Section, Surgical Oncology Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jiri Cerny
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - David Taieb
- Department of Nuclear Medicine, La Timone University Hospital, CERIMED, Aix-Marseille University, Marseille, France
| | - Jakub Rohlena
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic
| | - Jiri Neuzil
- Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czech Republic.,School of Pharmacy and Medical Science, Griffith University, Southport, Qld, Australia
| | - Chunzhang Yang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Karel Pacak
- Section of Medical Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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15
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Ramón J, Vila-Julià F, Molina-Granada D, Molina-Berenguer M, Melià MJ, García-Arumí E, Torres-Torronteras J, Cámara Y, Martí R. Therapy Prospects for Mitochondrial DNA Maintenance Disorders. Int J Mol Sci 2021; 22:6447. [PMID: 34208592 PMCID: PMC8234938 DOI: 10.3390/ijms22126447] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial DNA depletion and multiple deletions syndromes (MDDS) constitute a group of mitochondrial diseases defined by dysfunctional mitochondrial DNA (mtDNA) replication and maintenance. As is the case for many other mitochondrial diseases, the options for the treatment of these disorders are rather limited today. Some aggressive treatments such as liver transplantation or allogeneic stem cell transplantation are among the few available options for patients with some forms of MDDS. However, in recent years, significant advances in our knowledge of the biochemical pathomechanisms accounting for dysfunctional mtDNA replication have been achieved, which has opened new prospects for the treatment of these often fatal diseases. Current strategies under investigation to treat MDDS range from small molecule substrate enhancement approaches to more complex treatments, such as lentiviral or adenoassociated vector-mediated gene therapy. Some of these experimental therapies have already reached the clinical phase with very promising results, however, they are hampered by the fact that these are all rare disorders and so the patient recruitment potential for clinical trials is very limited.
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Affiliation(s)
- Javier Ramón
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ferran Vila-Julià
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - David Molina-Granada
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Miguel Molina-Berenguer
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Maria Jesús Melià
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Elena García-Arumí
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Javier Torres-Torronteras
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Yolanda Cámara
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Ramon Martí
- Research Group on Neuromuscular and Mitochondrial Diseases, Vall d’Hebron Research Institute, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (J.R.); (F.V.-J.); (D.M.-G.); (M.M.-B.); (M.J.M.); (E.G.-A.); (J.T.-T.); (Y.C.)
- Biomedical Network Research Centre on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029 Madrid, Spain
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16
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Jacinto S, Guerreiro P, de Oliveira RM, Cunha-Oliveira T, Santos MJ, Grazina M, Rego AC, Outeiro TF. MPV17 Mutations Are Associated With a Quiescent Energetic Metabolic Profile. Front Cell Neurosci 2021; 15:641264. [PMID: 33815063 PMCID: PMC8011494 DOI: 10.3389/fncel.2021.641264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/08/2021] [Indexed: 02/03/2023] Open
Abstract
Mutations in the MPV17 gene are associated with hepatocerebral form of mitochondrial depletion syndrome. The mechanisms through which MPV17 mutations cause respiratory chain dysfunction and mtDNA depletion is still unclear. The MPV17 gene encodes an inner membrane mitochondrial protein that was recently described to function as a non-selective channel. Although its exact function is unknown, it is thought to be important in the maintenance of mitochondrial membrane potential (ΔΨm). To obtain more information about the role of MPV17 in human disease, we investigated the effect of MPV17 knockdown and of selected known MPV17 mutations associated with MPV17 disease in vitro. We used different approaches in order to evaluate the cellular consequences of MPV17 deficiency. We found that lower levels of MPV17 were associated with impaired mitochondrial respiration and with a quiescent energetic metabolic profile. All the mutations studied destabilized the protein, resulting in reduced protein levels. We also demonstrated that different mutations caused different cellular abnormalities, including increased ROS production, decreased oxygen consumption, loss of ΔΨm, and mislocalization of MPV17 protein. Our study provides novel insight into the molecular effects of MPV17 mutations and opens novel possibilities for testing therapeutic strategies for a devastating group of disorders.
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Affiliation(s)
- Sandra Jacinto
- Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Serviço de Neurologia Pediátrica, Hospital Dona Estefânia, Centro Hospitalar Universitário Lisboa Central-EPE, Lisboa, Portugal
| | - Patrícia Guerreiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Switch Laboratory, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Switch Laboratory, Department of Cellular and Molecular Medicine, Katholiek Universiteit (KU), Leuven, Belgium
| | - Rita Machado de Oliveira
- CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | | | - Maria João Santos
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Portugal
| | - Manuela Grazina
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Portugal
| | - Ana Cristina Rego
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.,Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,Max Planck Institute for Experimental Medicine, Göttingen, Germany
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17
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Yap ZY, Strucinska K, Matsuzaki S, Lee S, Si Y, Humphries K, Tarnopolsky MA, Yoon WH. A biallelic pathogenic variant in the OGDH gene results in a neurological disorder with features of a mitochondrial disease. J Inherit Metab Dis 2021; 44:388-400. [PMID: 32383294 PMCID: PMC7647956 DOI: 10.1002/jimd.12248] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/29/2020] [Accepted: 04/30/2020] [Indexed: 12/27/2022]
Abstract
2-Oxoglutarate dehydrogenase (OGDH) is a rate-limiting enzyme in the mitochondrial TCA cycle, encoded by the OGDH gene. α-Ketoglutarate dehydrogenase (OGDH) deficiency was previously reported in association with developmental delay, hypotonia, and movement disorders and metabolic decompensation, with no genetic data provided. Using whole exome sequencing, we identified two individuals carrying a homozygous missense variant c.959A>G (p.N320S) in the OGDH gene. These individuals presented with global developmental delay, elevated lactate, ataxia and seizure. Fibroblast analysis and modeling of the mutation in Drosophila were used to evaluate pathogenicity of the variant. Skin fibroblasts from subject # 2 showed a decrease in both OGDH protein and enzyme activity. Transfection of human OGDH cDNA in HEK293 cells carrying p.N320S also produced significantly lower protein levels compared to those with wild-type cDNA. Loss of Drosophila Ogdh (dOgdh) caused early developmental lethality, rescued by expressing wild-type dOgdh (dOgdhWT ) or human OGDH (OGDHWT ) cDNA. In contrast, expression to the mutant OGDH (OGDHN320S ) or dOgdh carrying homologous mutations to human OGDH p.N320S variant (dOgdhN324S ) failed to rescue lethality of dOgdh null mutants. Knockdown of dOgdh in the nervous system resulted in locomotion defects which were rescued by dOgdhWT expression but not by dOgdhN324S expression. Collectively, the results indicate that c.959A>G variant in OGDH leads to an amino acid change (p.N320S) causing a severe loss of OGDH protein function. Our study establishes in the first time a genetic link between an OGDH gene mutation and OGDH deficiency.
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Affiliation(s)
- Zheng Yie Yap
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Klaudia Strucinska
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Satoshi Matsuzaki
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Sukyeong Lee
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas
| | | | - Kenneth Humphries
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | | | - Wan Hee Yoon
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
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18
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Tozawa T, Nishimura A, Ueno T, Shikata A, Taura Y, Yoshida T, Nakagawa N, Wada T, Kosugi S, Uehara T, Takenouchi T, Kosaki K, Chiyonobu T. Complex hereditary spastic paraplegia associated with episodic visual loss caused by ACO2 variants. Hum Genome Var 2021; 8:4. [PMID: 33500398 PMCID: PMC7838304 DOI: 10.1038/s41439-021-00136-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 11/09/2022] Open
Abstract
Most patients with homozygous or compound heterozygous pathogenic ACO2 variants present with muscular hypotonia features, namely, infantile cerebellar-retinal degeneration. Recently, two studies reported rare familial cases of ACO2 variants presenting as complex hereditary spastic paraplegia (HSP) with broad clinical spectra. Here, we report the case of a 20-year-old Japanese woman with complex HSP caused by compound heterozygous ACO2 variants, revealing a new phenotype of episodic visual loss during febrile illness.
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Affiliation(s)
- Takenori Tozawa
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. .,Department of Pediatrics, Ayabe City Hospital, Ayabe, Japan.
| | - Akira Nishimura
- Department of Neonatology, Japanese Red Cross Society Kyoto Daiichi Hospital, Kyoto, Japan
| | - Tamaki Ueno
- Department of Pediatrics, Ayabe City Hospital, Ayabe, Japan.,Department of Pediatrics, Tokai Central Hospital, Kakamigahara, Japan
| | - Akane Shikata
- Kyoto Prefectural Maizuru Rehabilitation Center for Children, Maizuru, Japan
| | - Yoshihiro Taura
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takeshi Yoshida
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Naoko Nakagawa
- Department of Medical Ethics/Medical Genetics, Kyoto University School of Public Health, Kyoto, Japan
| | - Takahito Wada
- Department of Medical Ethics/Medical Genetics, Kyoto University School of Public Health, Kyoto, Japan
| | - Shinji Kosugi
- Department of Medical Ethics/Medical Genetics, Kyoto University School of Public Health, Kyoto, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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19
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Filograna R, Mennuni M, Alsina D, Larsson NG. Mitochondrial DNA copy number in human disease: the more the better? FEBS Lett 2020; 595:976-1002. [PMID: 33314045 PMCID: PMC8247411 DOI: 10.1002/1873-3468.14021] [Citation(s) in RCA: 204] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/02/2020] [Accepted: 11/26/2020] [Indexed: 12/19/2022]
Abstract
Most of the genetic information has been lost or transferred to the nucleus during the evolution of mitochondria. Nevertheless, mitochondria have retained their own genome that is essential for oxidative phosphorylation (OXPHOS). In mammals, a gene‐dense circular mitochondrial DNA (mtDNA) of about 16.5 kb encodes 13 proteins, which constitute only 1% of the mitochondrial proteome. Mammalian mtDNA is present in thousands of copies per cell and mutations often affect only a fraction of them. Most pathogenic human mtDNA mutations are recessive and only cause OXPHOS defects if present above a certain critical threshold. However, emerging evidence strongly suggests that the proportion of mutated mtDNA copies is not the only determinant of disease but that also the absolute copy number matters. In this review, we critically discuss current knowledge of the role of mtDNA copy number regulation in various types of human diseases, including mitochondrial disorders, neurodegenerative disorders and cancer, and during ageing. We also provide an overview of new exciting therapeutic strategies to directly manipulate mtDNA to restore OXPHOS in mitochondrial diseases.
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Affiliation(s)
- Roberta Filograna
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Mara Mennuni
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - David Alsina
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Nils-Göran Larsson
- Division of Molecular Metabolism, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.,Max Planck Institute for Biology of Ageing - Karolinska Institutet Laboratory, Karolinska Institutet, Stockholm, Sweden
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20
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Alkhater RA, Ahonen S, Minassian BA. SUCLA2 Arg407Trp mutation can cause a nonprogressive movement disorder - deafness syndrome. Ann Clin Transl Neurol 2020; 8:252-258. [PMID: 33231368 PMCID: PMC7818133 DOI: 10.1002/acn3.51247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/04/2020] [Accepted: 10/13/2020] [Indexed: 11/25/2022] Open
Abstract
SUCLA2 is a component of mitochondrial succinate‐CoA ligase and nucleotide diphosphokinase activities. Its absence results in Krebs cycle failure, mitochondrial DNA depletion, and a childhood‐fatal encephalomyopathy. We describe a purely neurologic allelic form of the disease consisting of deafness, putamenal hyperintensity on MRI and a myoclonic‐dystonic movement disorder unchanging from childhood into, so far, the late fourth decade. We show that succinate supplementation circumvents the Krebs cycle block, but does not correct the neurologic disease. Our patients’ Arg407Trp mutation has been reported in children with (yet) no MRI abnormalities. It remains possible that early succinate supplementation could impact the disease.
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Affiliation(s)
- Reem A. Alkhater
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
- Institute of Medical SciencesUniversity of TorontoTorontoOntarioCanada
- Johns’ Hopkins Aramco HealthcareDhahranSaudi Arabia
| | - Saija Ahonen
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
| | - Berge A. Minassian
- Program in Genetics and Genome BiologyThe Hospital for Sick ChildrenTorontoOntarioCanada
- Institute of Medical SciencesUniversity of TorontoTorontoOntarioCanada
- Division of NeurologyDepartment of PediatricsUniversity of Texas SouthwesternDallasTexasUSA
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21
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SUCLA2 mutations cause global protein succinylation contributing to the pathomechanism of a hereditary mitochondrial disease. Nat Commun 2020; 11:5927. [PMID: 33230181 PMCID: PMC7684291 DOI: 10.1038/s41467-020-19743-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/26/2020] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial acyl-coenzyme A species are emerging as important sources of protein modification and damage. Succinyl-CoA ligase (SCL) deficiency causes a mitochondrial encephalomyopathy of unknown pathomechanism. Here, we show that succinyl-CoA accumulates in cells derived from patients with recessive mutations in the tricarboxylic acid cycle (TCA) gene succinyl-CoA ligase subunit-β (SUCLA2), causing global protein hyper-succinylation. Using mass spectrometry, we quantify nearly 1,000 protein succinylation sites on 366 proteins from patient-derived fibroblasts and myotubes. Interestingly, hyper-succinylated proteins are distributed across cellular compartments, and many are known targets of the (NAD+)-dependent desuccinylase SIRT5. To test the contribution of hyper-succinylation to disease progression, we develop a zebrafish model of the SCL deficiency and find that SIRT5 gain-of-function reduces global protein succinylation and improves survival. Thus, increased succinyl-CoA levels contribute to the pathology of SCL deficiency through post-translational modifications. The pathomechanism of succinyl-CoA ligase (SCL) deficiency, a hereditary mitochondrial disease, is not fully understood. Here, the authors show that increased succinyl-CoA levels contribute to SCL pathology by causing global protein hyper-succinylation.
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22
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Chen W, Wang Z, Xu W, Tian R, Zeng J. Dibutyl phthalate contamination accelerates the uptake and metabolism of sugars by microbes in black soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 262:114332. [PMID: 32182534 DOI: 10.1016/j.envpol.2020.114332] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/21/2020] [Accepted: 03/04/2020] [Indexed: 06/10/2023]
Abstract
Dibutyl phthalate (DBP) is widely used as plasticizer and has been detected in the environment, posing a threat to animal health. However, the effects of DBP on agricultural microbiomes are not known. In this study, DBP levels in black soil were evaluated, and the impact of DBP contamination on the uptake and metabolism of sugars in microbes was assessed by glucose absorption tests, metaproteomics, metabolomics, enzyme activity assays and computational simulation analysis. The results indicated that DBP contamination accelerated glucose consumption and upregulated the expression of porins and periplasmic monosaccharide ATP-binding cassette (ABC) transporter solute-binding proteins (SBPs). DBP and its metabolic intermediates (carboxymuconate and butanol) may form a stable complex with sugar transporters and enhance the rigidity and stability of these proteins. Sugar metabolism resulting in the generation of ATP and reducing agent (NADPH), as well as the expression of some key enzymes (dehydrogenases) were also upregulated by DBP treatment. Moreover, a diverse bacterial community appears to utilize sugar, suggesting that there are widespread effects of DBP contamination on soil microbial ecosystems. The results of this study provide a theoretical basis for investigating the toxicological effects of DBP on microbes in black soil.
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Affiliation(s)
- Wenjing Chen
- Center for Ecological Research, Northeast Forestry University, Heilongjiang Province, Harbin, 150040, China; Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar, 161006, China; College of Life Sciences, Agriculture and Forestry, Qiqihar University, Heilongjiang Province, Qiqihar, 161006, China.
| | - Zhigang Wang
- Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar, 161006, China; College of Life Sciences, Agriculture and Forestry, Qiqihar University, Heilongjiang Province, Qiqihar, 161006, China.
| | - Weihui Xu
- Heilongjiang Provincial Technology Innovation Center of Agromicrobial Preparation Industrialization, Qiqihar, 161006, China; College of Life Sciences, Agriculture and Forestry, Qiqihar University, Heilongjiang Province, Qiqihar, 161006, China.
| | - Renmao Tian
- Institute for Food Safety and Health, Illinois Institute of Technology, Chicago, IL, 60501, USA.
| | - Jin Zeng
- Nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
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23
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Abstract
Mitochondrial disease presenting in childhood is characterized by clinical, biochemical and genetic complexity. Some children are affected by canonical syndromes, but the majority have nonclassical multisystemic disease presentations involving virtually any organ in the body. Each child has a unique constellation of clinical features and disease trajectory, leading to enormous challenges in diagnosis and management of these heterogeneous disorders. This review discusses the classical mitochondrial syndromes presenting most frequently in childhood and then presents an organ-based perspective including systems less frequently linked to mitochondrial disease, such as skin and hair abnormalities and immune dysfunction. An approach to diagnosis is then presented, encompassing clinical evaluation and biochemical, neuroimaging and genetic investigations, and emphasizing the problem of phenocopies. The impact of next-generation sequencing is discussed, together with the importance of functional validation of novel genetic variants never previously linked to mitochondrial disease. The review concludes with a brief discussion of currently available and emerging therapies. The field of mitochondrial medicine has made enormous strides in the last 30 years, with approaching 400 different genes across two genomes now linked to primary mitochondrial disease. However, many important questions remain unanswered, including the reasons for tissue specificity and variability of clinical presentation of individuals sharing identical gene defects, and a lack of disease-modifying therapies and biomarkers to monitor disease progression and/or response to treatment.
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Affiliation(s)
- S Rahman
- Mitochondrial Research Group, UCL Great Ormond Street Institute of Child Health, London, UK
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24
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McGuire PJ. Chemical individuality in T cells: A Garrodian view of immunometabolism. Immunol Rev 2020; 295:82-100. [PMID: 32236968 DOI: 10.1111/imr.12854] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/28/2020] [Accepted: 03/01/2020] [Indexed: 02/06/2023]
Abstract
Metabolically quiescent T cells circulate throughout the body in search of antigen. Following engagement of their cognate receptors, T cells undergo metabolic reprogramming to support their activation, differentiation, and ultimately function. In the spirit of Sir Archibald Garrod, this metabolic reprogramming actually imparts a chemical individuality which confers advantage, while in others confers vulnerability, depending upon the milieu. Studying T cell immunometabolism in the context of inborn errors of metabolism allows one to define essential pathways of intermediary metabolism as well metabolic vulnerabilities and plasticity. Inborn errors of metabolism, a class of diseases first named by Garrod, have a long history of being informative for common physiologic and pathologic processes. This endeavor may be accomplished through the study of patients, animal models, and in vitro models of inborn errors of metabolism. In this review, the basics of intermediary metabolism and core metabolic pathways will be discussed, along with their relationship to T cell immunometabolism. Due to their pleiotropic nature, the reader will be specifically directed toward various inborn errors of metabolism which may be helpful for answering important questions about the role of metabolism in T cells.
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Affiliation(s)
- Peter J McGuire
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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25
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Guo X, Park JE, Gallart-Palau X, Sze SK. Oxidative Damage to the TCA Cycle Enzyme MDH1 Dysregulates Bioenergetic Enzymatic Activity in the Aged Murine Brain. J Proteome Res 2020; 19:1706-1717. [DOI: 10.1021/acs.jproteome.9b00861] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Xue Guo
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Jung Eun Park
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Xavier Gallart-Palau
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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26
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Abstract
Mitochondrial disorders present in a myriad of ways, which causes them to be included in the differential diagnosis for many patients with undiagnosed disease. A subset of mitochondrial disorders are caused by intrinsic defects in the mitochondrial replication machinery, leading to loss of cellular mitochondrial content over time. The diagnosis of mitochondrial disease is complex. Several best-practice guides are available that enable a higher likelihood of detecting a mitochondrial disorder. The application of genomic sequencing and advanced physiologic analysis of the electron transport chain can offer more definitive evidence of mitochondrial dysfunction.
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27
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Sommerville EW, Dalla Rosa I, Rosenberg MM, Bruni F, Thompson K, Rocha M, Blakely EL, He L, Falkous G, Schaefer AM, Yu‐Wai‐Man P, Chinnery PF, Hedstrom L, Spinazzola A, Taylor RW, Gorman GS. Identification of a novel heterozygous guanosine monophosphate reductase (GMPR) variant in a patient with a late-onset disorder of mitochondrial DNA maintenance. Clin Genet 2020; 97:276-286. [PMID: 31600844 PMCID: PMC7004030 DOI: 10.1111/cge.13652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/18/2019] [Accepted: 09/27/2019] [Indexed: 12/18/2022]
Abstract
Autosomal dominant progressive external ophthalmoplegia (adPEO) is a late-onset, Mendelian mitochondrial disorder characterised by paresis of the extraocular muscles, ptosis, and skeletal-muscle restricted multiple mitochondrial DNA (mtDNA) deletions. Although dominantly inherited, pathogenic variants in POLG, TWNK and RRM2B are among the most common genetic defects of adPEO, identification of novel candidate genes and the underlying pathomechanisms remains challenging. We report the clinical, genetic and molecular investigations of a patient who presented in the seventh decade of life with PEO. Oxidative histochemistry revealed cytochrome c oxidase-deficient fibres and occasional ragged red fibres showing subsarcolemmal mitochondrial accumulation in skeletal muscle, while molecular studies identified the presence of multiple mtDNA deletions. Negative candidate screening of known nuclear genes associated with PEO prompted diagnostic exome sequencing, leading to the prioritisation of a novel heterozygous c.547G>C variant in GMPR (NM_006877.3) encoding guanosine monophosphate reductase, a cytosolic enzyme required for maintaining the cellular balance of adenine and guanine nucleotides. We show that the novel c.547G>C variant causes aberrant splicing, decreased GMPR protein levels in patient skeletal muscle, proliferating and quiescent cells, and is associated with subtle changes in nucleotide homeostasis protein levels and evidence of disturbed mtDNA maintenance in skeletal muscle. Despite confirmation of GMPR deficiency, demonstrating marked defects of mtDNA replication or nucleotide homeostasis in patient cells proved challenging. Our study proposes that GMPR is the 19th locus for PEO and highlights the complexities of uncovering disease mechanisms in late-onset PEO phenotypes.
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Affiliation(s)
- Ewen W. Sommerville
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Ilaria Dalla Rosa
- Department of Clinical and Movement Neurosciences, UCL Queens Square Institute of Neurology, Royal Free CampusUniversity College LondonLondonUK
| | | | - Francesco Bruni
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
- Department of Biosciences, Biotechnologies and BiopharmaceuticsUniversity of Bari “ldo Moro”BariItaly
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Mariana Rocha
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Emma L. Blakely
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Gavin Falkous
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Andrew M. Schaefer
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Patrick Yu‐Wai‐Man
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and UCL Institute of OphthalmologyLondonUK
- MRC Mitochondrial Biology UnitUniversity of CambridgeCambridgeUK
- Cambridge Centre for Brain Repair, Department of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
| | - Patrick F. Chinnery
- Department of Clinical Neuroscience & Medical Research Council Mitochondrial Biology UnitSchool of Clinical Medicine, University of CambridgeCambridgeUK
| | - Lizbeth Hedstrom
- Department of BiologyBrandeis UniversityWalthamMA
- Department of ChemistryBrandeis University, 415 South St.WalthamMA
| | - Antonella Spinazzola
- Department of Clinical and Movement Neurosciences, UCL Queens Square Institute of Neurology, Royal Free CampusUniversity College LondonLondonUK
- MRC Centre for Neuromuscular DiseasesUCL Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
| | - Gráinne S. Gorman
- Wellcome Centre for Mitochondrial Research, Institute of NeuroscienceNewcastle UniversityNewcastle upon TyneUK
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28
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Abstract
The POLG gene encodes the mitochondrial DNA polymerase that is responsible for replication of the mitochondrial genome. Mutations in POLG can cause early childhood mitochondrial DNA (mtDNA) depletion syndromes or later-onset syndromes arising from mtDNA deletions. POLG mutations are the most common cause of inherited mitochondrial disorders, with as many as 2% of the population carrying these mutations. POLG-related disorders comprise a continuum of overlapping phenotypes with onset from infancy to late adulthood. The six leading disorders caused by POLG mutations are Alpers-Huttenlocher syndrome, which is one of the most severe phenotypes; childhood myocerebrohepatopathy spectrum, which presents within the first 3 years of life; myoclonic epilepsy myopathy sensory ataxia; ataxia neuropathy spectrum; autosomal recessive progressive external ophthalmoplegia; and autosomal dominant progressive external ophthalmoplegia. This Review describes the clinical features, pathophysiology, natural history and treatment of POLG-related disorders, focusing particularly on the neurological manifestations of these conditions.
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29
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Abstract
This chapter focuses on the methods to measure unique metabolites, specific enzymes, and metabolic flux in fatty acid β-oxidation, and on biochemical assays of tricarboxylic acid (TCA) cycle enzymes and the pyruvate dehydrogenase complex. These assays play an important role in the diagnosis of genetic diseases, newborn screening, and in cancer and metabolism research. The rationale, protocol, pros and cons, and alternative methods are discussed. Nevertheless, each laboratory should adapt the preferred method optimizing sample preparation and assay conditions for linearity and a low signal-to-noise ratio. The reader is also referred to the additional literature citing methods and clinical descriptions of the various diseases.
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30
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Lim A, Thomas RH. The mitochondrial epilepsies. Eur J Paediatr Neurol 2020; 24:47-52. [PMID: 31973983 DOI: 10.1016/j.ejpn.2019.12.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/19/2023]
Abstract
Mitochondria are vital organelles within cells that undertake many important metabolic roles, the most significant of which is to generate energy to support organ function. Dysfunction of the mitochondrion can lead to a wide range of clinical features, predominantly affecting organs with a high metabolic demand such as the brain. One of the main neurological manifestations of mitochondrial disease is metabolic epilepsies. These epileptic seizures are more frequently of posterior quadrant and occipital lobe onset, more likely to present with non-convulsive status epilepticus which may last months and be more resistant to treatment from the onset. The onset of can be of any age. Childhood onset epilepsy is a major phenotypic feature in mitochondrial disorders such as Alpers-Huttenlocher syndrome, pyruvate dehydrogenase complex deficiencies, and Leigh syndrome. Meanwhile, adults with classical mitochondrial disease syndrome such as MELAS, MERFF or POLG-related disorders could present with either focal or generalised seizures. There are no specific curative treatments for mitochondrial epilepsy. Generally, the epileptic seizures should be managed by specialist neurologist with appropriate use of anticonvulsants. As a general rule, especially in disorders associated with mutation in POLG, sodium valproate is best avoided because hepato-toxicity can be fulminant and fatal.
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Affiliation(s)
- Albert Lim
- Department of Paediatrics, Great Northern Children's Hospital, Queen Victoria Rd, Newcastle-Upon-Tyne, NE1 4LP, United Kingdom; Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle-Upon-Tyne, NE2 4HH, United Kingdom
| | - Rhys H Thomas
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle-Upon-Tyne, NE2 4HH, United Kingdom; Department of Neurology, Royal Victoria Infirmary, Queen Victoria Rd, Newcastle-Upon-Tyne, NE1 4LP, United Kingdom; Institute of Neuroscience, Henry Wellcome Building, Framlington Place, Newcastle University, Newcastle-Upon-Tyne, NE2 4HH, United Kingdom.
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31
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Smirlis D, Dingli F, Pescher P, Prina E, Loew D, Rachidi N, Späth GF. SILAC-based quantitative proteomics reveals pleiotropic, phenotypic modulation in primary murine macrophages infected with the protozoan pathogen Leishmania donovani. J Proteomics 2019; 213:103617. [PMID: 31846769 DOI: 10.1016/j.jprot.2019.103617] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 12/04/2019] [Accepted: 12/13/2019] [Indexed: 01/06/2023]
Abstract
Leishmaniases are major vector-borne tropical diseases responsible for great human morbidity and mortality, caused by protozoan, trypanosomatid parasites of the genus Leishmania. In the mammalian host, parasites survive and multiply within mononuclear phagocytes, especially macrophages. However, the underlying mechanisms by which Leishmania spp. affect their host are not fully understood. Herein, proteomic alterations of primary, bone marrow-derived BALB/c macrophages are documented after 72 h of infection with Leishmania donovani insect-stage promastigotes, applying a SILAC-based, quantitative proteomics approach. The protocol was optimised by combining strong anion exchange and gel electrophoresis fractionation that displayed similar depth of analysis (combined total of 6189 mouse proteins). Our analyses revealed 86 differentially modulated proteins (35 showing increased and 51 decreased abundance) in response to Leishmania donovani infection. The proteomics results were validated by analysing the abundance of selected proteins. Intracellular Leishmania donovani infection led to changes in various host cell biological processes, including primary metabolism and catabolic process, with a significant enrichment in lysosomal organisation. Overall, our analysis establishes the first proteome of bona fide primary macrophages infected ex vivo with Leishmania donovani, revealing new mechanisms acting at the host/pathogen interface. SIGNIFICANCE: Little is known on proteome changes that occur in primary macrophages after Leishmania donovani infection. This study describes a SILAC-based quantitative proteomics approach to characterise changes of bone marrow-derived macrophages infected with L. donovani promastigotes for 72 h. With the application of SILAC and the use of SAX and GEL fractionation methods, we have tested new routes for proteome quantification of primary macrophages. The protocols developed here can be applicable to other diseases and pathologies. Moreover, this study sheds important new light on the "proteomic reprogramming" of infected macrophages in response to L. donovani promastigotes that affects primary metabolism, cellular catabolic processes, and lysosomal/vacuole organisation. Thus, our study reveals key molecules and processes that act at the host/pathogen interface that may inform on new immuno- or chemotherapeutic interventions to combat leishmaniasis.
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Affiliation(s)
- Despina Smirlis
- Institut Pasteur and Institut National de Santé et Recherche Médicale INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France; Hellenic Pasteur Institute, Molecular Parasitology Laboratory, Athens, Greece.
| | - Florent Dingli
- Laboratoire de Spectrométrie de Masse Protéomique, Centre de Recherche, Institut Curie, Université de recherche PSL, Paris, France
| | - Pascale Pescher
- Institut Pasteur and Institut National de Santé et Recherche Médicale INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France
| | - Eric Prina
- Institut Pasteur and Institut National de Santé et Recherche Médicale INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France
| | - Damarys Loew
- Laboratoire de Spectrométrie de Masse Protéomique, Centre de Recherche, Institut Curie, Université de recherche PSL, Paris, France
| | - Najma Rachidi
- Institut Pasteur and Institut National de Santé et Recherche Médicale INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France
| | - Gerald F Späth
- Institut Pasteur and Institut National de Santé et Recherche Médicale INSERM U1201, Unité de Parasitologie Moléculaire et Signalisation, Paris, France.
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32
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Chinopoulos C. Quantification of mitochondrial DNA from peripheral tissues: Limitations in predicting the severity of neurometabolic disorders and proposal of a novel diagnostic test. Mol Aspects Med 2019; 71:100834. [PMID: 31740079 DOI: 10.1016/j.mam.2019.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/07/2019] [Accepted: 11/12/2019] [Indexed: 11/25/2022]
Abstract
Neurometabolic disorders stem from errors in metabolic processes yielding a neurological phenotype. A subset of those disorders encompasses mitochondrial abnormalities partially due to mitochondrial DNA (mtDNA) depletion. mtDNA depletion can be attributed to inheritance, spontaneous mutations or acquired from drug-related toxicities. In the armamentarium of diagnostic procedures, mtDNA quantification is a standard for disease classification. However, alterations in mtDNA obtained from peripheral tissues such as skin fibroblasts and blood cells do not often reflect the severity of the affected organ, in this case, the brain. The purpose of this review is to highlight the pitfalls of quantitating mtDNA from peripheral -and not limited to-tissues for diagnosing patients suffering from a variety of mtDNA depletion syndromes exhibiting neurologic abnormalities. In lieu, a qualitative test of mitochondrial substrate-level phosphorylation -even from peripheral tissues-reflecting the ability of mitochondria to rely on glutaminolysis in the presence of respiratory chain defects is proposed as a novel diagnostic assessment of mitochondrial functionality.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Tuzolto St. 37-47, Budapest, 1094, Hungary.
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33
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A Brief History of Mitochondrial Pathologies. Int J Mol Sci 2019; 20:ijms20225643. [PMID: 31718067 PMCID: PMC6888695 DOI: 10.3390/ijms20225643] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 01/19/2023] Open
Abstract
The history of "mitochondrial pathologies", namely genetic pathologies affecting mitochondrial metabolism because of mutations in nuclear DNA-encoded genes for proteins active inside mitochondria or mutations in mitochondrial DNA-encoded genes, began in 1988. In that year, two different groups of researchers discovered, respectively, large-scale single deletions of mitochondrial DNA (mtDNA) in muscle biopsies from patients with "mitochondrial myopathies" and a point mutation in the mtDNA gene for subunit 4 of NADH dehydrogenase (MTND4), associated with maternally inherited Leber's hereditary optic neuropathy (LHON). Henceforth, a novel conceptual "mitochondrial genetics", separate from mendelian genetics, arose, based on three features of mtDNA: (1) polyplasmy; (2) maternal inheritance; and (3) mitotic segregation. Diagnosis of mtDNA-related diseases became possible through genetic analysis and experimental approaches involving histochemical staining of muscle or brain sections, single-fiber polymerase chain reaction (PCR) of mtDNA, and the creation of patient-derived "cybrid" (cytoplasmic hybrid) immortal fibroblast cell lines. The availability of the above-mentioned techniques along with the novel sensitivity of clinicians to such disorders led to the characterization of a constantly growing number of pathologies. Here is traced a brief historical perspective on the discovery of autonomous pathogenic mtDNA mutations and on the related mendelian pathology altering mtDNA integrity.
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34
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Genetic architecture related to contour feathers density in an F 2 resource population via a genome-wide association study. 3 Biotech 2019; 9:400. [PMID: 31656738 DOI: 10.1007/s13205-019-1918-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/24/2019] [Indexed: 01/02/2023] Open
Abstract
The density of contour feathers is an important trait as it is closely related to heat dissipation in birds. Thus, identification of the major genes that control this trait will be useful to improve heat tolerance in chicken. So far, no GWAS study for the density of contour feathers in birds has been previously published; therefore, this study was aimed to identify genomic regions controlling the density of contour feathers. A total of 1252 hens were genotyped, using the 600 K Affymetrix Axiom Chicken Genotyping Array. The association analyses were performed using the GenABEL package in the R program. In brief, 146 significant SNP markers were mainly located on chromosome 1 and were identified to associate with the density of contour feathers in the current GWAS analysis. Moreover, we identified several within/nearby candidate genes (SUCLA2, DNAJC15, DHRS12, MLNR, and RB1) that are either directly or indirectly involved in the genetic control of the density of contour feathers in chicken. This study laid the foundation for studying the mechanism that underlies the density of chicken feathers. Furthermore, it is feasible to shear the back feathers of live chickens and measure the density of the feathers to improve heat tolerance in breeding practice.
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35
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Li X, Li L, Sun Y, Lv F, Zhang G, Liu W, Zhang M, Jiang H, Liu S. Whole exome sequencing reveals two novel compound heterozygous mutations in TWNK as a cause of the hepatocerebral form of mitochondrial DNA depletion syndrome: a case report. BMC MEDICAL GENETICS 2019; 20:146. [PMID: 31455269 PMCID: PMC6712797 DOI: 10.1186/s12881-019-0875-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 08/11/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Although Mitochondrial DNA depletion syndrome (MDS) can be classified into three forms: myopathic, encephalomyopathic and hepatocerebral form, it is difficult to identify its form due to its clinical heterogeneity. Therefore, it is very important to conduct molecular genetic analysis on suspected patients. This study presented a male 38 weeks and 5 days infant with liver cytolysis and leukodystrophy. CASE PRESENTATION A male infant proband was admitted to the department of NICU for feeding intolerance, irregular rhythm of respiration, hypoglycemia, lactic acidosis, liver cytolysis and neurological abnormalities. He was onset of mild jaundice with leukodystrophy and high lactate and phenylderivatives for urine organic acids on the 7th day. Whole exome sequencing (WES) and Sanger sequencing were performed to screen and confirm the suspicious pathogenic mutations. The results revealed this proband carried two compound heterozygous mutations in TWNK: c.1186 C > T / p.Pro396Ser and c.1844 G > C / p.Gly615Ala inherited by an autosomal recessive form from his parents, of which protein conservative analysis and structural modeling supported the pathogenicity of the two mutations. Unfortunately, the conditions described above were not improved until he was discharged from the hospital on the 23rd day and died at 4 months of age. CONCLUSIONS In this study, we investigated a Chinese family with the hepatocerebral form of MDS and conducted WES and Sanger sequencing to explore the causative mutations for this proband born from non-consanguineous and healthy parents. We identified two novel TWNK c.1186 C > T/ c.1844 G > C compound heterozygous mutations which were probably the disease-causing mutations of hepatocerebral form of MDS and described the clinical manifestations of the proband, which expanded the phenotypic spectrum of MDS caused by variants in TWNK. This study also emphasized WES technology can provide the genetic diagnosis of Mendelian genetic disease.
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Affiliation(s)
- Xianghong Li
- Department of Neonatology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China
| | - Liangshan Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China
| | - Yaqi Sun
- Shandong Provincial Key Laboratory of Metabolic Diseases and Qingdao Key Laboratory of Gout, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China
| | - Fuyan Lv
- Qingdao Women and Children's Hospital, Qingdao, 266034, China
| | - Guoqing Zhang
- Department of Orthopaedic Surgery, the Affiliated Hospital of Qingdao University, Qingdao, 266000, China
| | - Wenmiao Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China
| | - Meiyan Zhang
- Department of Neonatology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China
| | - Hong Jiang
- Department of Neonatology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China.
| | - Shiguo Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266000, China.
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Huang J, Nguyen VH, Hamblin KA, Maytum R, van der Giezen M, Fraser ME. ATP-specificity of succinyl-CoA synthetase from Blastocystis hominis. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:647-659. [PMID: 31282474 DOI: 10.1107/s2059798319007976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/03/2019] [Indexed: 11/10/2022]
Abstract
Succinyl-CoA synthetase (SCS) catalyzes the only step of the tricarboxylic acid cycle that leads to substrate-level phosphorylation. Some forms of SCS are specific for ADP/ATP or for GDP/GTP, while others can bind all of these nucleotides, generally with different affinities. The theory of `gatekeeper' residues has been proposed to explain the nucleotide-specificity. Gatekeeper residues lie outside the binding site and create specific electrostatic interactions with incoming nucleotides to determine whether the nucleotides can enter the binding site. To test this theory, the crystal structure of the nucleotide-binding domain in complex with Mg2+-ADP was determined, as well as the structures of four proteins with single mutations, K46βE, K114βD, V113βL and L227βF, and one with two mutations, K46βE/K114βD. The crystal structures show that the enzyme is specific for ADP/ATP because of interactions between the nucleotide and the binding site. Nucleotide-specificity is provided by hydrogen-bonding interactions between the adenine base and Gln20β, Gly111β and Val113β. The O atom of the side chain of Gln20β interacts with N6 of ADP, while the side-chain N atom interacts with the carbonyl O atom of Gly111β. It is the different conformations of the backbone at Gln20β, of the side chain of Gln20β and of the linker that make the enzyme ATP-specific. This linker connects the two subdomains of the ATP-grasp fold and interacts differently with adenine and guanine bases. The mutant proteins have similar conformations, although the L227βF mutant shows structural changes that disrupt the binding site for the magnesium ion. Although the K46βE/K114βD double mutant of Blastocystis hominis SCS binds GTP better than ATP according to kinetic assays, only the complex with Mg2+-ADP was obtained.
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Affiliation(s)
- Ji Huang
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Vinh H Nguyen
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Karleigh A Hamblin
- Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, England
| | - Robin Maytum
- School of Life Sciences, University of Bedfordshire, University Square, Luton LU1 3JU, England
| | | | - Marie E Fraser
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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Fukada M, Yamada K, Eda S, Inoue K, Ohba C, Matsumoto N, Saitsu H, Nakayama A. Identification of novel compound heterozygous mutations in ACO2 in a patient with progressive cerebral and cerebellar atrophy. Mol Genet Genomic Med 2019; 7:e00698. [PMID: 31106992 PMCID: PMC6625133 DOI: 10.1002/mgg3.698] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 01/29/2019] [Accepted: 04/08/2019] [Indexed: 01/24/2023] Open
Abstract
Background The tricarboxylic acid (TCA) cycle is a sequence of catabolic reactions within the mitochondrial matrix, and is a central pathway for cellular energy metabolism. Genetic defects affecting the TCA cycle are known to cause severe multisystem disorders. Methods We performed whole exome sequencing of genomic DNA of a patient with progressive cerebellar and cerebral atrophy, hypotonia, ataxia, seizure disorder, developmental delay, ophthalmological abnormalities and hearing loss. We also performed biochemical studies using patient fibroblasts. Results We identified new compound heterozygous mutations (c.1534G > A, p.Asp512Asn and c.1997G > C, p.Gly666Ala) in ACO2, which encodes aconitase 2, a component of the TCA cycle. In patient fibroblasts, the aconitase activity was reduced to 15% of that of the control, and the aconitase 2 level decreased to 36% of that of the control. As such a decrease in aconitase 2 in patient fibroblasts was partially restored by proteasome inhibition, mutant aconitase 2 was suggested to be relatively unstable and rapidly degraded after being synthesized. In addition, the activity of the father‐derived variant of aconitase 2 (p.Gly666Ala), which had a mutation near the active center, was 55% of that of wild‐type. Conclusion The marked reduction of aconitase activity in patient fibroblasts was due to the combination of decreased aconitase 2 amount and activity due to mutations. Reduced aconitase activity directly suppresses the TCA cycle, resulting in mitochondrial dysfunction, which may lead to symptoms similar to those observed in mitochondrial diseases.
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Affiliation(s)
- Masahide Fukada
- Department of Embryology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan
| | - Keitaro Yamada
- Department of Pediatric Neurology, Aichi Prefectural Colony Central Hospital, Aichi Human Service Center, Kasugai, Japan
| | - Shima Eda
- Department of Embryology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Chihiro Ohba
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Atsuo Nakayama
- Department of Embryology, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan.,Department of Neurochemistry, Nagoya University Graduate School of Medicine, Nagoya, Japan
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38
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Chen Z, Zhang F, Xu H. Human mitochondrial DNA diseases and Drosophila models. J Genet Genomics 2019; 46:201-212. [DOI: 10.1016/j.jgg.2019.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/05/2019] [Accepted: 03/25/2019] [Indexed: 01/06/2023]
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Demirbas D, Harris DJ, Arn PH, Huang X, Waisbren SE, Anselm I, Lerner‐Ellis JP, Wong L, Levy HL, Berry GT. Phenotypic variability in deficiency of the α subunit of succinate-CoA ligase. JIMD Rep 2019; 46:63-69. [PMID: 31240156 PMCID: PMC6498818 DOI: 10.1002/jmd2.12018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 12/31/2018] [Indexed: 12/30/2022] Open
Abstract
Succinyl-CoA synthetase or succinate-CoA ligase deficiency can result from biallelic mutations in SUCLG1 gene that encodes for the alpha subunit of the succinyl-CoA synthetase. Mutations in this gene were initially associated with fatal infantile lactic acidosis. We describe an individual with a novel biallelic pathogenic mutation in SUCLG1 with a less severe phenotype dominated by behavioral problems. The mutation was identified to be c.512A>G corresponding to a p.Asn171Ser change in the protein. The liquid chromatography tandem mass spectrometry-based enzyme activity assay on cultured fibroblasts revealed a markedly reduced activity of succinyl-CoA synthetase enzyme when both ATP and GTP were substrates, affecting both ADP-forming and GDP-forming functions of the enzyme.
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Affiliation(s)
- Didem Demirbas
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - David J. Harris
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Pamela H. Arn
- Department of PediatricsNemours Children's Health SystemJacksonvilleFlorida
| | - Xiaoping Huang
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Susan E. Waisbren
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Irina Anselm
- Department of NeurologyBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Jordan P. Lerner‐Ellis
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | | | - Harvey L. Levy
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
| | - Gerard T. Berry
- Division of Genetics and Genomics, Manton Center for Orphan Disease ResearchBoston Children's Hospital, Harvard Medical SchoolBostonMassachusetts
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40
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Oyarzabal A, Marin-Valencia I. Synaptic energy metabolism and neuronal excitability, in sickness and health. J Inherit Metab Dis 2019; 42:220-236. [PMID: 30734319 DOI: 10.1002/jimd.12071] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 01/06/2019] [Accepted: 01/30/2019] [Indexed: 12/11/2022]
Abstract
Most of the energy produced in the brain is dedicated to supporting synaptic transmission. Glucose is the main fuel, providing energy and carbon skeletons to the cells that execute and support synaptic function: neurons and astrocytes, respectively. It is unclear, however, how glucose is provided to and used by these cells under different levels of synaptic activity. It is even more unclear how diseases that impair glucose uptake and oxidation in the brain alter metabolism in neurons and astrocytes, disrupt synaptic activity, and cause neurological dysfunction, of which seizures are one of the most common clinical manifestations. Poor mechanistic understanding of diseases involving synaptic energy metabolism has prevented the expansion of therapeutic options, which, in most cases, are limited to symptomatic treatments. To shed light on the intersections between metabolism, synaptic transmission, and neuronal excitability, we briefly review current knowledge of compartmentalized metabolism in neurons and astrocytes, the biochemical pathways that fuel synaptic transmission at resting and active states, and the mechanisms by which disorders of brain glucose metabolism disrupt neuronal excitability and synaptic function and cause neurological disease in the form of epilepsy.
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Affiliation(s)
- Alfonso Oyarzabal
- Synaptic Metabolism Laboratory, Department of Neurology, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Isaac Marin-Valencia
- Laboratory of Developmental Neurobiology, The Rockefeller University, New York, New York
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41
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Chinopoulos C, Batzios S, van den Heuvel LP, Rodenburg R, Smeets R, Waterham HR, Turkenburg M, Ruiter JP, Wanders RJA, Doczi J, Horvath G, Dobolyi A, Vargiami E, Wevers RA, Zafeiriou D. Mutated SUCLG1 causes mislocalization of SUCLG2 protein, morphological alterations of mitochondria and an early-onset severe neurometabolic disorder. Mol Genet Metab 2019; 126:43-52. [PMID: 30470562 DOI: 10.1016/j.ymgme.2018.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 11/19/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer consisting of an alpha subunit encoded by SUCLG1, and a beta subunit encoded by either SUCLA2 or SUCLG2 catalyzing an ATP- or GTP-forming reaction, respectively, in the mitochondrial matrix. The deficiency of this enzyme represents an encephalomyopathic form of mtDNA depletion syndromes. We describe the fatal clinical course of a female patient with a pathogenic mutation in SUCLG1 (c.626C > A, p.Ala209Glu) heterozygous at the genomic DNA level, but homozygous at the transcriptional level. The patient exhibited early-onset neurometabolic abnormality culminating in severe brain atrophy and dystonia leading to death by the age of 3.5 years. Urine and plasma metabolite profiling was consistent with SUCL deficiency which was confirmed by enzyme analysis and lack of mitochondrial substrate-level phosphorylation (mSLP) in skin fibroblasts. Oxygen consumption- but not extracellular acidification rates were altered only when using glutamine as a substrate, and this was associated with mild mtDNA depletion and no changes in ETC activities. Immunoblot analysis revealed no detectable levels of SUCLG1, while SUCLA2 and SUCLG2 protein expressions were largely reduced. Confocal imaging of triple immunocytochemistry of skin fibroblasts showed that SUCLG2 co-localized only partially with the mitochondrial network which otherwise exhibited an increase in fragmentation compared to control cells. Our results outline the catastrophic consequences of the mutated SUCLG1 leading to strongly reduced SUCL activity, mSLP impairment, mislocalization of SUCLG2, morphological alterations in mitochondria and clinically to a severe neurometabolic disease, but in the absence of changes in mtDNA levels or respiratory complex activities.
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Affiliation(s)
| | - Spyros Batzios
- 1st Department of Pediatrics, "Hippokratio" General Hospital, Aristotle University, Thessaloniki, Greece; Department of Paediatric Metabolic Medicine, Great Ormond Street Hospital, London, UK
| | - Lambertus P van den Heuvel
- Department of Pediatrics, Radboud University Medical Centre, Nijmegen, The Netherlands; Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Richard Rodenburg
- Department of Pediatrics, Radboud University Medical Centre, Nijmegen, The Netherlands; Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Roel Smeets
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Marjolein Turkenburg
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Jos P Ruiter
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centers, University of Amsterdam, The Netherlands
| | - Judit Doczi
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - Gergo Horvath
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - Arpad Dobolyi
- MTA-ELTE Laboratory of Molecular and Systems Neurobiology, Department of Physiology and Neurobiology, Hungarian Academy of Sciences, Eotvos Lorand University, Budapest, Hungary; Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Euthymia Vargiami
- 1st Department of Pediatrics, "Hippokratio" General Hospital, Aristotle University, Thessaloniki, Greece
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Dimitrios Zafeiriou
- 1st Department of Pediatrics, "Hippokratio" General Hospital, Aristotle University, Thessaloniki, Greece.
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42
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Reversing wrinkled skin and hair loss in mice by restoring mitochondrial function. Cell Death Dis 2018; 9:735. [PMID: 30026579 PMCID: PMC6053453 DOI: 10.1038/s41419-018-0765-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 04/27/2018] [Accepted: 06/08/2018] [Indexed: 12/12/2022]
Abstract
Mitochondrial DNA (mtDNA) depletion is involved in mtDNA depletion syndromes, mitochondrial diseases, aging and aging-associated chronic diseases, and other human pathologies. To evaluate the consequences of depletion of mtDNA in the whole animal, we created an inducible mtDNA-depleter mouse expressing, in the polymerase domain of POLG1, a dominant-negative mutation to induce depletion of mtDNA in various tissues. These mice showed reduced mtDNA content, reduced mitochondrial gene expression, and instability of supercomplexes involved in oxidative phosphorylation (OXPHOS) resulting in reduced OXPHOS enzymatic activities. We demonstrate that ubiquitous depletion of mtDNA in mice leads to predominant and profound effects on the skin resulting in wrinkles and visual hair loss with an increased number of dysfunctional hair follicles and inflammatory responses. Development of skin wrinkle was associated with the significant epidermal hyperplasia, hyperkeratosis, increased expression of matrix metalloproteinases, and decreased expression of matrix metalloproteinase inhibitor TIMP1. We also discovered markedly increased skin inflammation that appears to be a contributing factor in skin pathology. Histopathologic analyses revealed dysfunctional hair follicles. mtDNA-depleter mice also show changes in expression of aging-associated markers including IGF1R, KLOTHO, VEGF, and MRPS5. mtDNA-repleter mice showed that, by turning off the mutant POLG1 transgene expression, mitochondrial function, as well as the skin and hair pathology, is reversed to wild-type level. To our knowledge that restoration of mitochondrial functions can reverse the skin and hair pathology is unprecedented.
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Huangyang P, Simon MC. Hidden features: exploring the non-canonical functions of metabolic enzymes. Dis Model Mech 2018; 11:11/8/dmm033365. [PMID: 29991493 PMCID: PMC6124551 DOI: 10.1242/dmm.033365] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The study of cellular metabolism has been rigorously revisited over the past decade, especially in the field of cancer research, revealing new insights that expand our understanding of malignancy. Among these insights is the discovery that various metabolic enzymes have surprising activities outside of their established metabolic roles, including in the regulation of gene expression, DNA damage repair, cell cycle progression and apoptosis. Many of these newly identified functions are activated in response to growth factor signaling, nutrient and oxygen availability, and external stress. As such, multifaceted enzymes directly link metabolism to gene transcription and diverse physiological and pathological processes to maintain cell homeostasis. In this Review, we summarize the current understanding of non-canonical functions of multifaceted metabolic enzymes in disease settings, especially cancer, and discuss specific circumstances in which they are employed. We also highlight the important role of subcellular localization in activating these novel functions. Understanding their non-canonical properties should enhance the development of new therapeutic strategies for cancer treatment. Summary: This Review summarizes recent findings about multifaceted metabolic enzymes with non-canonical activities outside their core biochemical functions, and how they may provide new therapeutic strategies for cancers.
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Affiliation(s)
- Peiwei Huangyang
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Departments of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - M Celeste Simon
- Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA .,Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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44
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Mice lacking the mitochondrial exonuclease MGME1 accumulate mtDNA deletions without developing progeria. Nat Commun 2018; 9:1202. [PMID: 29572490 PMCID: PMC5865154 DOI: 10.1038/s41467-018-03552-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 02/21/2018] [Indexed: 12/17/2022] Open
Abstract
Replication of mammalian mitochondrial DNA (mtDNA) is an essential process that requires high fidelity and control at multiple levels to ensure proper mitochondrial function. Mutations in the mitochondrial genome maintenance exonuclease 1 (MGME1) gene were recently reported in mitochondrial disease patients. Here, to study disease pathophysiology, we generated Mgme1 knockout mice and report that homozygous knockouts develop depletion and multiple deletions of mtDNA. The mtDNA replication stalling phenotypes vary dramatically in different tissues of Mgme1 knockout mice. Mice with MGME1 deficiency accumulate a long linear subgenomic mtDNA species, similar to the one found in mtDNA mutator mice, but do not develop progeria. This finding resolves a long-standing debate by showing that point mutations of mtDNA are the main cause of progeria in mtDNA mutator mice. We also propose a role for MGME1 in the regulation of replication and transcription termination at the end of the control region of mtDNA. It has been debated whether premature ageing in mitochondrial DNA mutator mice is driven by point mutations or deletions of mtDNA. Matic et al generate Mgme1 knockout mice and show here that these mice have tissue-specific replication stalling and accumulate deleted mtDNA, without developing progeria.
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45
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Abstract
The heart failure accounts for the highest mortality rate all over the world. The development of preventive therapeutic approaches is still in their infancy. Owing to the extremely high energy demand of the heart, the bioenergetics pathways need to respond efficiently based on substrate availability. The metabolic regulation of such heart bioenergetics is mediated by various rate limiting enzymes involved in energy metabolism. Although all the pertinent mechanisms are not clearly understood, the progressive decline in the activity of metabolic enzymes leading to diminished ATP production is known to cause progression of the heart failure. Therefore, metabolic therapy that can maintain the appropriate activities of metabolic enzymes can be a promising approach for the prevention and treatment of the heart failure. The flavonoids that constitute various human dietary ingredients also effectively offer a variety of health benefits. The flavonoids target a variety of metabolic enzymes and facilitate effective management of the equilibrium between production and utilization of energy in the heart. This review discusses the broad impact of metabolic enzymes in the heart functions and explains how the dysregulated enzyme activity causes the heart failure. In addition, the prospects of targeting dysregulated metabolic enzymes by developing flavonoid-based metabolic approaches are discussed.
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46
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Loss of succinyl-CoA synthase ADP-forming β subunit disrupts mtDNA stability and mitochondrial dynamics in neurons. Sci Rep 2017; 7:7169. [PMID: 28769029 PMCID: PMC5541051 DOI: 10.1038/s41598-017-05168-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/24/2017] [Indexed: 11/30/2022] Open
Abstract
Succinyl Coenzyme A synthetase (SCS) is a key mitochondrial enzyme. Defected SCS ADP-forming β subunit (SCS A-β) is linked to lethal infantile Leigh or leigh-like syndrome. However, the impacts of SCS A-β deficiency on mitochondria specifically in neurons have not yet been comprehensively investigated. Here, by down-regulating the expression levels of SCS A-β in cultured mouse neurons, we have found that SCS A-β deficiency induces severe mitochondrial dysfunction including lowered oxidative phosphorylation (OXPHOS) efficiency, increased mitochondrial superoxide production, and mtDNA depletion as well as aberrations of mitochondrial fusion and fission proteins, which eventually leads to neuronal stress. Our data also suggest that the deregulation of mitochondrial nucleoside diphosphate kinase (NDPK) together with defects in mitochondrial transcription factors including mitochondrial DNA pol γ and Twinkle contribute to SCS A-β deficiency-mediated mtDNA instability. Furthermore, we have found that SCS A-β deficiency has detrimental influence on neuronal mitochondrial dynamics. Put together, the results have furnished our knowledge on the pathogenesis of SCS A-β deficiency-related mitochondrial diseases and revealed the vital role of SCS A-β in maintaining neuronal mitochondrial quality control and neuronal physiology.
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47
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Couser NL, Marchuk DS, Smith LD, Arreola A, Kaiser-Rogers KA, Muenzer J, Pandya A, Gucsavas-Calikoglu M, Powell CM. Co-occurring Down syndrome and SUCLA2-related mitochondrial depletion syndrome. Am J Med Genet A 2017; 173:2720-2724. [PMID: 28749033 DOI: 10.1002/ajmg.a.38351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 06/09/2017] [Accepted: 06/14/2017] [Indexed: 01/23/2023]
Abstract
Mitochondrial DNA depletion syndrome 5 (MIM 612073) is a rare autosomal recessive disorder caused by homozygous or compound heterozygous pathogenic variants in the beta subunit of the succinate-CoA ligase gene located within the 13q14 band. We describe two siblings of Hispanic descent with SUCLA2-related mitochondrial depletion syndrome (encephalomyopathic form with methylmalonic aciduria); the older sibling is additionally affected with trisomy 21. SUCLA2 sequencing identified homozygous p.Arg284Cys pathogenic variants in both patients. This mutation has previously been identified in four individuals of Italian and Caucasian descent. The older sibling with concomitant disease has a more severe phenotype than what is typically described in patients with either SUCLA2-related mitochondrial depletion syndrome or Down syndrome alone. The younger sibling, who has a normal female chromosome complement, is significantly less affected compared to her brother. While the clinical and molecular findings have been reported in about 50 patients affected with a deficiency of succinate-CoA ligase caused by pathogenic variants in SUCLA2, this report describes the first known individual affected with both a mitochondrial depletion syndrome and trisomy 21.
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Affiliation(s)
- Natario L Couser
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Daniel S Marchuk
- University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Laurie D Smith
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Alexandra Arreola
- Department of Pathology & Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Kathleen A Kaiser-Rogers
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Pathology & Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Joseph Muenzer
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Arti Pandya
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Muge Gucsavas-Calikoglu
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Cynthia M Powell
- Department of Pediatrics, Division of Genetics and Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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48
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Viscomi C, Zeviani M. MtDNA-maintenance defects: syndromes and genes. J Inherit Metab Dis 2017; 40:587-599. [PMID: 28324239 PMCID: PMC5500664 DOI: 10.1007/s10545-017-0027-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 02/02/2023]
Abstract
A large group of mitochondrial disorders, ranging from early-onset pediatric encephalopathic syndromes to late-onset myopathy with chronic progressive external ophthalmoplegia (CPEOs), are inherited as Mendelian disorders characterized by disturbed mitochondrial DNA (mtDNA) maintenance. These errors of nuclear-mitochondrial intergenomic signaling may lead to mtDNA depletion, accumulation of mtDNA multiple deletions, or both, in critical tissues. The genes involved encode proteins belonging to at least three pathways: mtDNA replication and maintenance, nucleotide supply and balance, and mitochondrial dynamics and quality control. In most cases, allelic mutations in these genes may lead to profoundly different phenotypes associated with either mtDNA depletion or multiple deletions.
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Affiliation(s)
- Carlo Viscomi
- MRC-Mitochondrial Biology Unit, MRC MBU, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Massimo Zeviani
- MRC-Mitochondrial Biology Unit, MRC MBU, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.
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49
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Abela L, Spiegel R, Crowther LM, Klein A, Steindl K, Papuc SM, Joset P, Zehavi Y, Rauch A, Plecko B, Simmons TL. Plasma metabolomics reveals a diagnostic metabolic fingerprint for mitochondrial aconitase (ACO2) deficiency. PLoS One 2017; 12:e0176363. [PMID: 28463998 PMCID: PMC5413020 DOI: 10.1371/journal.pone.0176363] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 04/10/2017] [Indexed: 12/02/2022] Open
Abstract
Mitochondrial respiratory chain dysfunction has been identified in a number of neurodegenerative disorders. Infantile cerebellar-retinal degeneration associated with mutations in the mitochondrial aconitase 2 gene (ACO2) has been recently described as a neurodegenerative disease of autosomal recessive inheritance. To date there is no biomarker for ACO2 deficiency and diagnosis relies on genetic analysis. Here we report global metabolic profiling in eight patients with ACO2 deficiency. Using an LC-MS-based metabolomics platform we have identified several metabolites with affected plasma concentrations including the tricarboxylic acid cycle metabolites cis-aconitate, isocitrate and alpha-ketoglutarate, as well as phosphoenolpyruvate and hydroxybutyrate. Taken together we report a diagnostic metabolic fingerprint for mitochondrial aconitase 2 deficiency.
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Affiliation(s)
- Lucia Abela
- Division of Child Neurology, University Children’s Hospital Zurich, Zurich, Switzerland
- Children’s Research Centre, University Children’s Hospital Zurich, Zurich, Switzerland
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
| | - Ronen Spiegel
- Department of Pediatrics B, Emek Medical Center, Afula, Rappaport Faculty of Medicine, Technion, Israel
| | - Lisa M. Crowther
- Division of Child Neurology, University Children’s Hospital Zurich, Zurich, Switzerland
- Children’s Research Centre, University Children’s Hospital Zurich, Zurich, Switzerland
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
| | - Andrea Klein
- Division of Child Neurology, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Katharina Steindl
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Sorina Mihaela Papuc
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Pascal Joset
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Yoav Zehavi
- Department of Pediatrics B, Emek Medical Center, Afula, Rappaport Faculty of Medicine, Technion, Israel
| | - Anita Rauch
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Institute of Medical Genetics, University of Zurich, Schlieren, Switzerland
| | - Barbara Plecko
- Division of Child Neurology, University Children’s Hospital Zurich, Zurich, Switzerland
- Children’s Research Centre, University Children’s Hospital Zurich, Zurich, Switzerland
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
| | - Thomas Luke Simmons
- Division of Child Neurology, University Children’s Hospital Zurich, Zurich, Switzerland
- Children’s Research Centre, University Children’s Hospital Zurich, Zurich, Switzerland
- Radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- * E-mail:
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50
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Wang L. Mitochondrial purine and pyrimidine metabolism and beyond. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 35:578-594. [PMID: 27906631 DOI: 10.1080/15257770.2015.1125001] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Carefully balanced deoxynucleoside triphosphate (dNTP) pools are essential for both nuclear and mitochondrial genome replication and repair. Two synthetic pathways operate in cells to produce dNTPs, e.g., the de novo and the salvage pathways. The key regulatory enzymes for de novo synthesis are ribonucleotide reductase (RNR) and thymidylate synthase (TS), and this process is considered to be cytosolic. The salvage pathway operates both in the cytosol (TK1 and dCK) and the mitochondria (TK2 and dGK). Mitochondrial dNTP pools are separated from the cytosolic ones owing to the double membrane structure of the mitochondria, and are formed by the salvage enzymes TK2 and dGK together with NMPKs and NDPK in postmitotic tissues, while in proliferating cells the mitochondrial dNTPs are mainly imported from the cytosol produced by the cytosolic pathways. Imbalanced mitochondrial dNTP pools lead to mtDNA depletion and/or deletions resulting in serious mitochondrial diseases. The mtDNA depletion syndrome is caused by deficiencies not only in enzymes in dNTP synthesis (TK2, dGK, p53R2, and TP) and mtDNA replication (mtDNA polymerase and twinkle helicase), but also in enzymes in other metabolic pathways such as SUCLA2 and SUCLG1, ABAT and MPV17. Basic questions are why defects in these enzymes affect dNTP synthesis and how important is mitochondrial nucleotide synthesis in the whole cell/organism perspective? This review will focus on recent studies on purine and pyrimidine metabolism, which have revealed several important links that connect mitochondrial nucleotide metabolism with amino acids, glucose, and fatty acid metabolism.
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Affiliation(s)
- Liya Wang
- a Department of Anatomy, Physiology and Biochemistry , Swedish University of Agricultural Sciences , Uppsala , Sweden
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