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Ullah Khan S, Daniela Hernández-González K, Ali A, Shakeel Raza Rizvi S. Diabetes and the fabkin complex: A dual-edged sword. Biochem Pharmacol 2024; 223:116196. [PMID: 38588831 DOI: 10.1016/j.bcp.2024.116196] [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: 11/21/2023] [Revised: 03/27/2024] [Accepted: 04/05/2024] [Indexed: 04/10/2024]
Abstract
The Fabkin complex, composed of FABP4, ADK, and NDPKs, emerges as a novel regulator of insulin-producing beta cells, offering promising prospects for diabetes treatment. Our approach, which combines literature review and database analysis, sets the stage for future research. These findings hold significant implications for both diabetes treatment and research, as they present potential therapeutic targets for personalized treatment, leading to enhanced patient outcomes and a deeper comprehension of the disease. The multifaceted role of the Fabkin complex in glucose metabolism, insulin resistance, anti-inflammation, beta cell proliferation, and vascular function underscores its therapeutic potential, reshaping diabetes management and propelling advancements in the field.
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Affiliation(s)
- Safir Ullah Khan
- Department of Zoology, Wildlife & Fisheries, Faculty of sciences, Pir Mehr Ali Shah Arid Agriculture University, P.C. 46300, Rawalpindi, Pakistan
| | - Karla Daniela Hernández-González
- Facultad de Biología, Universidad Veracruzana, Circuito Gonzalo Aguirre Beltrán s/n, Zona Universitaria, C.P. 91000 Xalapa, Veracruz, México
| | - Amir Ali
- Nanoscience and Nanotechnology Program, Center for Research and Advanced Studies of the IPN, Mexico City, Mexico
| | - Syed Shakeel Raza Rizvi
- Department of Zoology, Wildlife & Fisheries, Faculty of sciences, Pir Mehr Ali Shah Arid Agriculture University, P.C. 46300, Rawalpindi, Pakistan.
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2
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Wang C, Zhao F, Wu Z, Cai X, Zhou M, Hou Y. Mitochondria-Associated Protein FgNdk1 Regulates the Development, Pathogenicity, and SDHI Fungicide Sensitivity of Fusarium graminearum by Interacting with Succinate Dehydrogenase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:3913-3925. [PMID: 38355300 DOI: 10.1021/acs.jafc.3c07934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Nucleoside diphosphate kinase (NDK) plays an important role in many cellular processes in all organisms. In this study, we functionally characterized a nucleoside diphosphate kinase (FgNdk1) in Fusarium graminearum, a causal agent of Fusarium head blight (FHB). FgNdk1 was involved in the generation of energy in the electron-transfer chain by interacting with succinate dehydrogenase (FgSdhA, FgSdhC1, and FgSdhC2). Deletion of FgNdk1 not only resulted in abnormal mitochondrial morphology, decreased ATP content, defective fungal development, and impairment in the formation of the toxisome but also led to the suppressed expression level of DON biosynthesis enzymes, decreased DON biosynthesis, and declined pathogenicity as well. Furthermore, deletion of FgNdk1 caused increasing transcriptional levels of FgSdhC1 and FgdhC2, in the presence of pydiflumetofen, related to the decreased sensitivity to SDHI fungicides. Overall, this study identified a new regulatory mechanism of FgNdk1 in the pathogenicity and SDHI fungicide sensitivity of Fusarium graminearum.
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Affiliation(s)
- Chenguang Wang
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Feifei Zhao
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - ZhiWen Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Xiaowei Cai
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Mingguo Zhou
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Yiping Hou
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
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3
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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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4
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Galceran F, Digirolamo FA, Rengifo M, Reigada C, Saye M, Maciel BJ, Estecho IG, Errasti AE, Pereira CA, Miranda MR. Identifying inhibitors of Trypanosoma cruzi nucleoside diphosphate kinase 1 as potential repurposed drugs for Chagas' disease. Biochem Pharmacol 2023; 216:115766. [PMID: 37634596 DOI: 10.1016/j.bcp.2023.115766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 08/29/2023]
Abstract
Trypanosoma cruzi is the causative agent of Chagas' disease, an endemic and neglected disease. The treatment is limited to only two drugs, benznidazole (BZL) and nifurtimox (NFX), introduced more than fifty years ago and no new advances have been made since then. Nucleoside diphosphate kinases (NDPK) are key metabolic enzymes which have gained interest as drug targets of pathogen organisms. Taking advantage of the computer-assisted drug repurposing approaches, in the present work we initiate a search of potential T. cruzi nucleoside diphosphate kinase 1 (TcNDPK1) inhibitors over an ∼ 12,000 compound structures database to find drugs targeted to this enzyme with trypanocidal activity. Four medicines were selected and evaluated in vitro, ketorolac (KET, an anti-inflamatory), dutasteride (DUT, used to treat benign prostatic hyperplasia), nebivolol and telmisartan (NEB and TEL, used to treat high blood pressure). The four compounds were weak inhibitors and presented different trypanocidal effect on epimastigotes, trypomastigotes and intracellular stages. NEB and TEL were the most active drugs with increased effect on intracellular stages, (IC50 = 2.25 µM and 13.21 µM respectively), and selectivity indexes of 13.01 and 8.59 respectively, showing comparable effect to BZL, the first line drug for Chagas' disease treatment. In addition, both presented positive interactions when combined with BZL. Finally, transgenic epimastigotes with increased expression of TcNDPK1 were more resistant to TEL and NEB, suggesting that TcNDPK1 is at least one of the molecular targets. In view of the results, NEB and TEL could be repurposed medicines for Chagas' disease therapy.
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Affiliation(s)
- Facundo Galceran
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Fabio A Digirolamo
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Marcos Rengifo
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Chantal Reigada
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Melisa Saye
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Belen J Maciel
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Ivana G Estecho
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Andrea E Errasti
- Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Claudio A Pereira
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina
| | - Mariana R Miranda
- Universidad de Buenos Aires, Facultad de Medicina, Instituto de Investigaciones Médicas A. Lanari, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Instituto de Investigaciones Médicas (IDIM), Laboratorio de Parasitología Molecular, Buenos Aires, Argentina.
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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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Hydrogen peroxide initiates oxidative stress and proteomic alterations in meningothelial cells. Sci Rep 2022; 12:14519. [PMID: 36008468 PMCID: PMC9411503 DOI: 10.1038/s41598-022-18548-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 08/16/2022] [Indexed: 11/26/2022] Open
Abstract
Meningothelial cells (MECs) are fundamental cells of the sheaths covering the brain and optic nerve, where they build a brain/optic nerve-cerebral spinal fluid (CSF) barrier that prevents the free flow of CSF from the subarachnoid space, but their exact roles and underlying mechanisms remain unclear. Our attempt here was to investigate the influence elicited by hydrogen peroxide (H2O2) on functional changes of MECs. Our study showed that cell viability of MECs was inhibited after cells were exposed to oxidative agents. Cells subjected to H2O2 at the concentration of 150 µM for 24 h and 48 h exhibited an elevation of reactive oxygen species (ROS) activity, decrease of total antioxidant capacity (T-AOC) level and reduced mitochondrial membrane potential (ΔΨm) compared with control cells. 95 protein spots with more than twofold difference were detected in two dimensional electrophoresis (2DE) gels through proteomics assay following H2O2 exposure for 48 h, 10 proteins were identified through TOF/MS analysis. Among the proteomic changes explored, 8 proteins related to energy metabolism, mitochondrial function, structural regulation, and cell cycle control were downregulated. Our study provides key insights that enhance our understanding of the role of MECs in the pathology of brain and optic nerve disorders.
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7
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Metabolic cycles and signals for insulin secretion. Cell Metab 2022; 34:947-968. [PMID: 35728586 PMCID: PMC9262871 DOI: 10.1016/j.cmet.2022.06.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 06/01/2022] [Accepted: 06/04/2022] [Indexed: 02/03/2023]
Abstract
In this review, we focus on recent developments in our understanding of nutrient-induced insulin secretion that challenge a key aspect of the "canonical" model, in which an oxidative phosphorylation-driven rise in ATP production closes KATP channels. We discuss the importance of intrinsic β cell metabolic oscillations; the phasic alignment of relevant metabolic cycles, shuttles, and shunts; and how their temporal and compartmental relationships align with the triggering phase or the secretory phase of pulsatile insulin secretion. Metabolic signaling components are assigned regulatory, effectory, and/or homeostatic roles vis-à-vis their contribution to glucose sensing, signal transmission, and resetting the system. Taken together, these functions provide a framework for understanding how allostery, anaplerosis, and oxidative metabolism are integrated into the oscillatory behavior of the secretory pathway. By incorporating these temporal as well as newly discovered spatial aspects of β cell metabolism, we propose a much-refined MitoCat-MitoOx model of the signaling process for the field to evaluate.
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Chen YM, Chen W, Xu Y, Lu CS, Zhu MM, Sun RY, Wang Y, Chen Y, Shi J, Wang D. Novel compound heterozygous SUCLG1 variants may contribute to mitochondria DNA depletion syndrome-9. Mol Genet Genomic Med 2022; 10:e2010. [PMID: 35762302 PMCID: PMC9482404 DOI: 10.1002/mgg3.2010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 05/18/2022] [Accepted: 06/08/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Succinate-CoA ligase/synthetase (SCS) deficiency is responsible for encephalomyopathy with mitochondrial DNA depletion and mild methylmalonic aciduria. Variants in SUCLG1, the nuclear gene encoding the alpha subunit of the SCS enzyme playing a pivotal role in maintaining mtDNA integrity and stability, are associated with mitochondrial DNA depletion syndrome 9 (MTDPS9). METHODS In this study, we reported an infant with clinical features of MTDPS9 from China. Whole exome sequencing (WES) was used to identify the genetic cause. Bioinformatic analysis and mtDNA level detection were performed to assess pathogenicity. RESULTS The proband manifested with hypotonia, lactic acidosis, mild methylmalonic aciduria, hearing loss and psychomotor retardation. WES identified new compound heterozygous SUCLG1 variants of c.601A>G (p.R201G) in exon 6 and c.871G>C (p.A291P) in exon 8. Computational analysis predicted that these missense variants might alter structure stability and mitochondrial translocation of SUCLG1. qRT-PCR showed 68% depletion of mtDNA content in proband as compared to controls. CONCLUSION Novel compound heterozygous variants c.601A>G (p.R201G) and c.871G>C (p.A291P) in SUCLG1 may cause MTDPS9 in this family. Our finding should be helpful for molecular diagnosis, genetic counseling and clinical management of SCS deficiency disorders.
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Affiliation(s)
- Yi-Ming Chen
- Department of Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Wei Chen
- Department of Radiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yue Xu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chao-Sheng Lu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Mian-Mian Zhu
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Rong-Yue Sun
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yihong Wang
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yuan Chen
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jiaming Shi
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Dan Wang
- Department of Pediatrics, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
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Roy A, Kandettu A, Ray S, Chakrabarty S. Mitochondrial DNA replication and repair defects: Clinical phenotypes and therapeutic interventions. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148554. [PMID: 35341749 DOI: 10.1016/j.bbabio.2022.148554] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 03/06/2022] [Accepted: 03/16/2022] [Indexed: 12/15/2022]
Abstract
Mitochondria is a unique cellular organelle involved in multiple cellular processes and is critical for maintaining cellular homeostasis. This semi-autonomous organelle contains its circular genome - mtDNA (mitochondrial DNA), that undergoes continuous cycles of replication and repair to maintain the mitochondrial genome integrity. The majority of the mitochondrial genes, including mitochondrial replisome and repair genes, are nuclear-encoded. Although the repair machinery of mitochondria is quite efficient, the mitochondrial genome is highly susceptible to oxidative damage and other types of exogenous and endogenous agent-induced DNA damage, due to the absence of protective histones and their proximity to the main ROS production sites. Mutations in replication and repair genes of mitochondria can result in mtDNA depletion and deletions subsequently leading to mitochondrial genome instability. The combined action of mutations and deletions can result in compromised mitochondrial genome maintenance and lead to various mitochondrial disorders. Here, we review the mechanism of mitochondrial DNA replication and repair process, key proteins involved, and their altered function in mitochondrial disorders. The focus of this review will be on the key genes of mitochondrial DNA replication and repair machinery and the clinical phenotypes associated with mutations in these genes.
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Affiliation(s)
- Abhipsa Roy
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Amoolya Kandettu
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Swagat Ray
- Department of Life Sciences, School of Life and Environmental Sciences, University of Lincoln, Lincoln LN6 7TS, United Kingdom
| | - Sanjiban Chakrabarty
- Department of Cell and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India.
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Abstract
Significance: The small, multicopy mitochondrial genome (mitochondrial DNA [mtDNA]) is essential for efficient energy production, as alterations in its coding information or a decrease in its copy number disrupt mitochondrial ATP synthesis. However, the mitochondrial replication machinery encounters numerous challenges that may limit its ability to duplicate this important genome and that jeopardize mtDNA stability, including various lesions in the DNA template, topological stress, and an insufficient nucleotide supply. Recent Advances: An ever-growing array of DNA repair or maintenance factors are being reported to localize to the mitochondria. We review current knowledge regarding the mitochondrial factors that may contribute to the tolerance or repair of various types of changes in the mitochondrial genome, such as base damage, incorporated ribonucleotides, and strand breaks. We also discuss the newly discovered link between mtDNA instability and activation of the innate immune response. Critical Issues: By which mechanisms do mitochondria respond to challenges that threaten mtDNA maintenance? What types of mtDNA damage are repaired, and when are the affected molecules degraded instead? And, finally, which forms of mtDNA instability trigger an immune response, and how? Future Directions: Further work is required to understand the contribution of the DNA repair and damage-tolerance factors present in the mitochondrial compartment, as well as the balance between mtDNA repair and degradation. Finally, efforts to understand the events underlying mtDNA release into the cytosol are warranted. Pursuing these and many related avenues can improve our understanding of what goes wrong in mitochondrial disease. Antioxid. Redox Signal. 36, 885-905.
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Affiliation(s)
- Gustavo Carvalho
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Bruno Marçal Repolês
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Isabela Mendes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Paulina H Wanrooij
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
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11
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Lacombe ML, Lamarche F, De Wever O, Padilla-Benavides T, Carlson A, Khan I, Huna A, Vacher S, Calmel C, Desbourdes C, Cottet-Rousselle C, Hininger-Favier I, Attia S, Nawrocki-Raby B, Raingeaud J, Machon C, Guitton J, Le Gall M, Clary G, Broussard C, Chafey P, Thérond P, Bernard D, Fontaine E, Tokarska-Schlattner M, Steeg P, Bièche I, Schlattner U, Boissan M. The mitochondrially-localized nucleoside diphosphate kinase D (NME4) is a novel metastasis suppressor. BMC Biol 2021; 19:228. [PMID: 34674701 PMCID: PMC8529772 DOI: 10.1186/s12915-021-01155-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 09/17/2021] [Indexed: 12/11/2022] Open
Abstract
Background Mitochondrial nucleoside diphosphate kinase (NDPK-D, NME4, NM23-H4) is a multifunctional enzyme mainly localized in the intermembrane space, bound to the inner membrane. Results We constructed loss-of-function mutants of NDPK-D, lacking either NDP kinase activity or membrane interaction and expressed mutants or wild-type protein in cancer cells. In a complementary approach, we performed depletion of NDPK-D by RNA interference. Both loss-of-function mutations and NDPK-D depletion promoted epithelial-mesenchymal transition and increased migratory and invasive potential. Immunocompromised mice developed more metastases when injected with cells expressing mutant NDPK-D as compared to wild-type. This metastatic reprogramming is a consequence of mitochondrial alterations, including fragmentation and loss of mitochondria, a metabolic switch from respiration to glycolysis, increased ROS generation, and further metabolic changes in mitochondria, all of which can trigger pro-metastatic protein expression and signaling cascades. In human cancer, NME4 expression is negatively associated with markers of epithelial-mesenchymal transition and tumor aggressiveness and a good prognosis factor for beneficial clinical outcome. Conclusions These data demonstrate NME4 as a novel metastasis suppressor gene, the first localizing to mitochondria, pointing to a role of mitochondria in metastatic dissemination. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01155-5.
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Affiliation(s)
- Marie-Lise Lacombe
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Frederic Lamarche
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Olivier De Wever
- Laboratory of Experimental Cancer Research, Department of Human Structure and Repair, Cancer Research Institute Ghent (CRIG), Ghent University, Ghent, Belgium
| | | | - Alyssa Carlson
- Molecular Biology and Biochemistry Department, Wesleyan University, Middletown, USA
| | - Imran Khan
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, USA
| | - Anda Huna
- Cancer Research Center of Lyon, INSERM U1052, CNRS UMR 5286, Léon Bérard Center, Lyon University, Lyon, France
| | - Sophie Vacher
- Unit of Pharmacogenetics, Department of Genetics, Curie Institute, Paris, France
| | - Claire Calmel
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Céline Desbourdes
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Cécile Cottet-Rousselle
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Isabelle Hininger-Favier
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Stéphane Attia
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Béatrice Nawrocki-Raby
- Reims Champagne Ardenne University, INSERM, P3Cell UMR-S 1250, SFR CAP-SANTE, Reims, France
| | - Joël Raingeaud
- INSERM U1279, Gustave Roussy Institute, Villejuif, France
| | - Christelle Machon
- Cancer Research Center of Lyon, INSERM U1052, CNRS UMR 5286, Léon Bérard Center, Lyon University, Lyon, France
| | - Jérôme Guitton
- Cancer Research Center of Lyon, INSERM U1052, CNRS UMR 5286, Léon Bérard Center, Lyon University, Lyon, France
| | - Morgane Le Gall
- Proteomics Platform 3P5, Paris University, Cochin Institute, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Guilhem Clary
- Proteomics Platform 3P5, Paris University, Cochin Institute, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Cedric Broussard
- Proteomics Platform 3P5, Paris University, Cochin Institute, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Philippe Chafey
- Proteomics Platform 3P5, Paris University, Cochin Institute, INSERM, U1016, CNRS, UMR8104, Paris, France
| | - Patrice Thérond
- AP-HP, CHU Bicêtre, Laboratory of Biochemistry, Le Kremlin-Bicêtre Hospital, Le Kremlin-Bicêtre, France.,EA7537, Paris Saclay University, Châtenay-Malabry, France
| | - David Bernard
- Cancer Research Center of Lyon, INSERM U1052, CNRS UMR 5286, Léon Bérard Center, Lyon University, Lyon, France
| | - Eric Fontaine
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Malgorzata Tokarska-Schlattner
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), Grenoble, France
| | - Patricia Steeg
- Women's Malignancies Branch, Center for Cancer Research, National Cancer Institute, Bethesda, USA
| | - Ivan Bièche
- Unit of Pharmacogenetics, Department of Genetics, Curie Institute, Paris, France
| | - Uwe Schlattner
- Université Grenoble Alpes, INSERM U1055, Laboratory of Fundamental and Applied Bioenergetics (LBFA), Institut Universitaire de France (IUF), Grenoble, France.
| | - Mathieu Boissan
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France. .,AP-HP, Laboratory of Biochemistry and Hormonology, Tenon Hospital, Paris, France.
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12
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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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13
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Sant’Anna-Silva ACB, Perez-Valencia JA, Sciacovelli M, Lalou C, Sarlak S, Tronci L, Nikitopoulou E, Meszaros AT, Frezza C, Rossignol R, Gnaiger E, Klocker H. Succinate Anaplerosis Has an Onco-Driving Potential in Prostate Cancer Cells. Cancers (Basel) 2021; 13:cancers13071727. [PMID: 33917317 PMCID: PMC8038717 DOI: 10.3390/cancers13071727] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/23/2021] [Accepted: 04/02/2021] [Indexed: 12/29/2022] Open
Abstract
Simple Summary Depending on the availability of nutrients and increased metabolic demands, tumor cells rearrange their metabolism to survive and, ultimately, proliferate. Here, the authors investigated the effect of succinate, a metabolite of the mitochondrial citric acid cycle, on malignant and non-malignant prostate cells. They analyzed uptake through membrane transporters and intracellular accumulation, which subsequently fuels metabolism and enhances oncogenic properties of the tumor cells. The findings shed light to the metabolic adaptations that prostate tumor cells undergo, providing a better understanding of metabolic rewiring and strategies for therapeutic intervention. Abstract Tumor cells display metabolic alterations when compared to non-transformed cells. These characteristics are crucial for tumor development, maintenance and survival providing energy supplies and molecular precursors. Anaplerosis is the property of replenishing the TCA cycle, the hub of carbon metabolism, participating in the biosynthesis of precursors for building blocks or signaling molecules. In advanced prostate cancer, an upshift of succinate-driven oxidative phosphorylation via mitochondrial Complex II was reported. Here, using untargeted metabolomics, we found succinate accumulation mainly in malignant cells and an anaplerotic effect contributing to biosynthesis, amino acid, and carbon metabolism. Succinate also stimulated oxygen consumption. Malignant prostate cells displayed higher mitochondrial affinity for succinate when compared to non-malignant prostate cells and the succinate-driven accumulation of metabolites induced expression of mitochondrial complex subunits and their activities. Moreover, extracellular succinate stimulated migration, invasion, and colony formation. Several enzymes linked to accumulated metabolites in the malignant cells were found upregulated in tumor tissue datasets, particularly NME1 and SHMT2 mRNA expression. High expression of the two genes was associated with shorter disease-free survival in prostate cancer cohorts. Moreover, in-vitro expression of both genes was enhanced in prostate cancer cells upon succinate stimulation. In conclusion, the data indicate that uptake of succinate from the tumor environment has an anaplerotic effect that enhances the malignant potential of prostate cancer cells.
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Affiliation(s)
- Ana Carolina B. Sant’Anna-Silva
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, 6020 Innsbruck, Austria; (A.T.M.); (E.G.)
- Oroboros Instruments GmbH, 6020 Innsbruck, Austria
- Correspondence: (A.C.B.S.-S.); (H.K.)
| | | | - Marco Sciacovelli
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Claude Lalou
- Institut National de la Santé Et de la Recherche Médicale (INSERM) U1211, Bordeaux University, 33076 Bordeaux, France; (C.L.); (S.S.); (R.R.)
| | - Saharnaz Sarlak
- Institut National de la Santé Et de la Recherche Médicale (INSERM) U1211, Bordeaux University, 33076 Bordeaux, France; (C.L.); (S.S.); (R.R.)
| | - Laura Tronci
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Efterpi Nikitopoulou
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Andras T. Meszaros
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, 6020 Innsbruck, Austria; (A.T.M.); (E.G.)
| | - Christian Frezza
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Rodrigue Rossignol
- Institut National de la Santé Et de la Recherche Médicale (INSERM) U1211, Bordeaux University, 33076 Bordeaux, France; (C.L.); (S.S.); (R.R.)
| | - Erich Gnaiger
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, 6020 Innsbruck, Austria; (A.T.M.); (E.G.)
- Oroboros Instruments GmbH, 6020 Innsbruck, Austria
| | - Helmut Klocker
- Department of Surgery, Division of Experimental Urology, University Hospital for Urology, Medical University Innsbruck, 6020 Innsbruck, Austria
- Correspondence: (A.C.B.S.-S.); (H.K.)
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14
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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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15
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Adam K, Ning J, Reina J, Hunter T. NME/NM23/NDPK and Histidine Phosphorylation. Int J Mol Sci 2020; 21:E5848. [PMID: 32823988 PMCID: PMC7461546 DOI: 10.3390/ijms21165848] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 12/15/2022] Open
Abstract
The NME (Non-metastatic) family members, also known as NDPKs (nucleoside diphosphate kinases), were originally identified and studied for their nucleoside diphosphate kinase activities. This family of kinases is extremely well conserved through evolution, being found in prokaryotes and eukaryotes, but also diverges enough to create a range of complexity, with homologous members having distinct functions in cells. In addition to nucleoside diphosphate kinase activity, some family members are reported to possess protein-histidine kinase activity, which, because of the lability of phosphohistidine, has been difficult to study due to the experimental challenges and lack of molecular tools. However, over the past few years, new methods to investigate this unstable modification and histidine kinase activity have been reported and scientific interest in this area is growing rapidly. This review presents a global overview of our current knowledge of the NME family and histidine phosphorylation, highlighting the underappreciated protein-histidine kinase activity of NME family members, specifically in human cells. In parallel, information about the structural and functional aspects of the NME family, and the knowns and unknowns of histidine kinase involvement in cell signaling are summarized.
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Affiliation(s)
| | | | | | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; (K.A.); (J.N.); (J.R.)
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16
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Abstract
Glucose-induced (physiological) insulin secretion from the islet β-cell involves interplay between cationic (i.e., changes in intracellular calcium) and metabolic (i.e., generation of hydrophobic and hydrophilic second messengers) events. A large body of evidence affirms support for novel regulation, by G proteins, of specific intracellular signaling events, including actin cytoskeletal remodeling, transport of insulin-containing granules to the plasma membrane for fusion, and secretion of insulin into the circulation. This article highlights the following aspects of GPCR-G protein biology of the islet. First, it overviews our current understanding of the identity of a wide variety of G protein regulators and their modulatory roles in GPCR-G protein-effector coupling, which is requisite for optimal β-cell function under physiological conditions. Second, it describes evidence in support of novel, noncanonical, GPCR-independent mechanisms of activation of G proteins in the islet. Third, it highlights the evidence indicating that abnormalities in G protein function lead to islet β-cell dysregulation and demise under the duress of metabolic stress and diabetes. Fourth, it summarizes observations of potential beneficial effects of GPCR agonists in preventing/halting metabolic defects in the islet β-cell under various pathological conditions (e.g., metabolic stress and inflammation). Lastly, it identifies knowledge gaps and potential avenues for future research in this evolving field of translational islet biology. Published 2020. Compr Physiol 10:453-490, 2020.
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Affiliation(s)
- Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Center for Translational Research in Diabetes, Biomedical Research Service, John D. Dingell VA Medical Center, Wayne State University, Detroit, Michigan, USA
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17
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Chinopoulos C, Seyfried TN. Mitochondrial Substrate-Level Phosphorylation as Energy Source for Glioblastoma: Review and Hypothesis. ASN Neuro 2019; 10:1759091418818261. [PMID: 30909720 PMCID: PMC6311572 DOI: 10.1177/1759091418818261] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common and malignant of the primary adult brain cancers. Ultrastructural and biochemical evidence shows that GBM cells exhibit mitochondrial abnormalities incompatible with energy production through oxidative phosphorylation (OxPhos). Under such conditions, the mitochondrial F0-F1 ATP synthase operates in reverse at the expense of ATP hydrolysis to maintain a moderate membrane potential. Moreover, expression of the dimeric M2 isoform of pyruvate kinase in GBM results in diminished ATP output, precluding a significant ATP production from glycolysis. If ATP synthesis through both glycolysis and OxPhos was impeded, then where would GBM cells obtain high-energy phosphates for growth and invasion? Literature is reviewed suggesting that the succinate-CoA ligase reaction in the tricarboxylic acid cycle can substantiate sufficient ATP through mitochondrial substrate-level phosphorylation (mSLP) to maintain GBM growth when OxPhos is impaired. Production of high-energy phosphates would be supported by glutaminolysis—a hallmark of GBM metabolism—through the sequential conversion of glutamine → glutamate → alpha-ketoglutarate → succinyl CoA → succinate. Equally important, provision of ATP through mSLP would maintain the adenine nucleotide translocase in forward mode, thus preventing the reverse-operating F0-F1 ATP synthase from depleting cytosolic ATP reserves. Because glucose and glutamine are the primary fuels driving the rapid growth of GBM and most tumors for that matter, simultaneous restriction of these two substrates or inhibition of mSLP should diminish cancer viability, growth, and invasion.
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18
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De la Casa-Fages B, Fernández-Eulate G, Gamez J, Barahona-Hernando R, Morís G, García-Barcina M, Infante J, Zulaica M, Fernández-Pelayo U, Muñoz-Oreja M, Urtasun M, Olaskoaga A, Zelaya V, Jericó I, Saez-Villaverde R, Catalina I, Sola E, Martínez-Sáez E, Pujol A, Ruiz M, Schlüter A, Spinazzola A, Muñoz-Blanco JL, Grandas F, Holt I, Álvarez V, López de Munaín A. Parkinsonism and spastic paraplegia type 7: Expanding the spectrum of mitochondrial Parkinsonism. Mov Disord 2019; 34:1547-1561. [PMID: 31433872 DOI: 10.1002/mds.27812] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 07/02/2019] [Accepted: 07/14/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Pathogenic variants in the spastic paraplegia type 7 gene cause a complicated hereditary spastic paraplegia phenotype associated with classical features of mitochondrial diseases, including ataxia, progressive external ophthalmoplegia, and deletions of mitochondrial DNA. OBJECTIVES To better characterize spastic paraplegia type 7 disease with a clinical, genetic, and functional analysis of a Spanish cohort of spastic paraplegia type 7 patients. METHODS Genetic analysis was performed in patients suspecting hereditary spastic paraplegia and in 1 patient with parkinsonism and Pisa syndrome, through next-generation sequencing, whole-exome sequencing, targeted Sanger sequencing, and multiplex ligation-dependent probe analysis, and blood mitochondrial DNA levels determined by quantitative polymerase chain reaction. RESULTS Thirty-five patients were found to carry homozygous or compound heterozygous pathogenic variants in the spastic paraplegia type 7 gene. Mean age at onset was 40 years (range, 12-63); 63% of spastic paraplegia type 7 patients were male, and three-quarters of all patients had at least one allele with the c.1529C>T (p.Ala510Val) mutation. Eighty percent of the cohort showed a complicated phenotype, combining ataxia and progressive external ophthalmoplegia (65% and 26%, respectively). Parkinsonism was observed in 21% of cases. Analysis of blood mitochondrial DNA indicated that both patients and carriers of spastic paraplegia type 7 pathogenic variants had markedly lower levels of mitochondrial DNA than control subjects (228 per haploid nuclear DNA vs. 176 vs. 573, respectively; P < 0.001). CONCLUSIONS Parkinsonism is a frequent finding in spastic paraplegia type 7 patients. Spastic paraplegia type 7 pathogenic variants impair mitochondrial DNA homeostasis irrespective of the number of mutant alleles, type of variant, and patient or carrier status. Thus, spastic paraplegia type 7 supports mitochondrial DNA maintenance, and variants in the gene may cause parkinsonism owing to mitochondrial DNA abnormalities. Moreover, mitochondrial DNA blood analysis could be a useful biomarker to detect at risk families. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Beatriz De la Casa-Fages
- Department of Neurology, Hospital General Universitario Gregorio Marañon, Madrid, Spain.,Movement Disorders Unit, National Referral Center for rare diseases with Movement Disorders (CSUR), Hospital General Universitario Gregorio Marañon, Madrid, Spain.,Neurosciences Area, Instituto Investigacion Sanitaria Gregorio Marañon, Madrid, Spain
| | - Gorka Fernández-Eulate
- Department of Neurology, Hospital Universitario Donostia, San Sebastian, Spain.,Department of Neurosciences, Instituto Biodonostia, San Sebastian, Spain
| | - Josep Gamez
- Department of Neurology, Hospital General Universitari Vall d'Hebron-UAB-VHIR, Barcelona, Spain.,European Reference Network on Rare Neurological Diseases (ERN-RND), Hospital General Universitari Vall d'Hebron-UAB, Barcelona, Spain
| | - Raúl Barahona-Hernando
- Department of Neurology, Hospital General Universitario Gregorio Marañon, Madrid, Spain.,ALS-Neuromuscular Unit, Hospital General Universitario Gregorio Marañon, Madrid, Spain.,Department of Neurology, Hospital Ruber Juan Bravo, Grupo Quironsalud, Madrid, Spain
| | - Germán Morís
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), Oviedo, Spain.,Department of Neurology, Hospital Universitario Central de Asturias, Oviedo, Spain
| | | | - Jon Infante
- Department of Neurology, Hospital Universitario Marques de Valdecilla-IDIVAL, University of Cantabria, Santander, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Spain
| | - Miren Zulaica
- Department of Neurosciences, Instituto Biodonostia, San Sebastian, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Spain
| | | | - Mikel Muñoz-Oreja
- Department of Neurosciences, Instituto Biodonostia, San Sebastian, Spain
| | - Miguel Urtasun
- Department of Neurology, Hospital Universitario Donostia, San Sebastian, Spain
| | | | - Victoria Zelaya
- Department of Pathology, Complejo Hospitalario de Navarra, Pamplona, Spain
| | - Ivonne Jericó
- Department of Neurology, Complejo Hospitalario de Navarra, Pamplona, Spain
| | | | - Irene Catalina
- Department of Neurology, Hospital General Universitario Gregorio Marañon, Madrid, Spain.,ALS-Neuromuscular Unit, Hospital General Universitario Gregorio Marañon, Madrid, Spain
| | - Emma Sola
- Department of Pathology, Hospital General Universitario Gregorio Marañon, Madrid, Spain
| | - Elena Martínez-Sáez
- Department of Pathology, Hospital General Universitari Vall d'Hebron-UAB-VHIR, Barcelona, Spain.,Department of Medicine, UAB, Barcelona, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Catalan Institution of Research and Advanced Studies (ICREA), Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), Institute Carlos III, Madrid, Spain
| | - Montserrat Ruiz
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), Institute Carlos III, Madrid, Spain
| | - Agatha Schlüter
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), Institute Carlos III, Madrid, Spain
| | - Antonella Spinazzola
- Department of Clinical Movement Neurosciences, UCL Queen Square Institute of Neurology, Royal Free Campus, London, United Kingdom.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Jose Luis Muñoz-Blanco
- Department of Neurology, Hospital General Universitario Gregorio Marañon, Madrid, Spain.,Neurosciences Area, Instituto Investigacion Sanitaria Gregorio Marañon, Madrid, Spain.,ALS-Neuromuscular Unit, Hospital General Universitario Gregorio Marañon, Madrid, Spain
| | - Francisco Grandas
- Department of Neurology, Hospital General Universitario Gregorio Marañon, Madrid, Spain.,Movement Disorders Unit, National Referral Center for rare diseases with Movement Disorders (CSUR), Hospital General Universitario Gregorio Marañon, Madrid, Spain.,Neurosciences Area, Instituto Investigacion Sanitaria Gregorio Marañon, Madrid, Spain
| | - Ian Holt
- Department of Neurosciences, Instituto Biodonostia, San Sebastian, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Victoria Álvarez
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), Oviedo, Spain.,Genetics Laboratory, AGC Medicine Laboratory, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Adolfo López de Munaín
- Department of Neurology, Hospital Universitario Donostia, San Sebastian, Spain.,Department of Neurosciences, Instituto Biodonostia, San Sebastian, Spain.,Department of Neurosciences UPV/EHU, San Sebastian, Spain.,Ciberned, Ministry of Science, Innovation and Universities, Madrid, Spain
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19
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Wang W, Dong M, Cui J, Xu F, Yan C, Ma C, Yi L, Tang W, Dong J, Wei Y. NME4 may enhance non‑small cell lung cancer progression by overcoming cell cycle arrest and promoting cellular proliferation. Mol Med Rep 2019; 20:1629-1636. [PMID: 31257488 PMCID: PMC6625391 DOI: 10.3892/mmr.2019.10413] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 05/28/2019] [Indexed: 02/03/2023] Open
Abstract
Nucleoside diphosphate kinase 4 (NME4) is abnormally expressed in a variety of cancer types. However, the function of the NME4 gene in non-small cell lung cancer (NSCLC) remains to be elucidated. In order to investigate the role of NME4 in NSCLC, the present study detected the expression of the NME4 gene in the Cancer Genome Atlas database, and in BEAS-2B, NCI-H1299 and A549 cell lines. NME4 was significantly overexpressed in NSCLC tissues and NSCLC cell lines. Furthermore, lentivirus-mediated knockdown vector infection, cell proliferation, cell cycle, apoptosis, colony formation and MTT assays were conducted to explore the effect of NME4 on NSCLC in vitro. After knockdown of NME4 with short hairpin RNA, the cell cycle was arrest at the G1 phase, and proliferation and colony formation were inhibited in the NCI-H1299 and A549 cell lines. The present results suggested that NME4 may serve as a novel tumor promoter, capable of enhancing NSCLC progression by overcoming cell cycle arrest and promoting proliferation.
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Affiliation(s)
- Wenqian Wang
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Ming Dong
- Gumei Community Health Center of Minhang District of Shanghai, Shanghai 201102, P.R. China
| | - Jie Cui
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Fei Xu
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Chen Yan
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Cheng Ma
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - La Yi
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Weifeng Tang
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Jingcheng Dong
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Ying Wei
- Department of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
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20
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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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21
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Mitochondrial DNA replication: clinical syndromes. Essays Biochem 2018; 62:297-308. [PMID: 29950321 DOI: 10.1042/ebc20170101] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 03/17/2018] [Accepted: 05/23/2018] [Indexed: 02/08/2023]
Abstract
Each nucleated cell contains several hundreds of mitochondria, which are unique organelles in being under dual genome control. The mitochondria contain their own DNA, the mtDNA, but most of mitochondrial proteins are encoded by nuclear genes, including all the proteins required for replication, transcription, and repair of mtDNA. MtDNA replication is a continuous process that requires coordinated action of several enzymes that are part of the mtDNA replisome. It also requires constant supply of deoxyribonucleotide triphosphates(dNTPs) and interaction with other mitochondria for mixing and unifying the mitochondrial compartment. MtDNA maintenance defects are a growing list of disorders caused by defects in nuclear genes involved in different aspects of mtDNA replication. As a result of defects in these genes, mtDNA depletion and/or multiple mtDNA deletions develop in affected tissues resulting in variable manifestations that range from adult-onset mild disease to lethal presentation early in life.
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22
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Lacombe ML, Tokarska-Schlattner M, Boissan M, Schlattner U. The mitochondrial nucleoside diphosphate kinase (NDPK-D/NME4), a moonlighting protein for cell homeostasis. J Transl Med 2018; 98:582-588. [PMID: 29491425 DOI: 10.1038/s41374-017-0004-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/12/2017] [Accepted: 11/13/2017] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial nucleoside diphosphate kinase (NDPK-D; synonyms: NME4, NM23-H4) represents the major mitochondrial NDP kinase. The homohexameric complex emerged as a protein with multiple functions in bioenergetics and phospholipid signaling. It occurs at different but precise mitochondrial locations and can affect among other mitochondrial shapes and dynamics, as well as the specific elimination of defective mitochondria or cells via mitophagy or apoptosis. With these various functions in cell homeostasis, NDPK-D/NME4 adds to the group of so-called moonlighting (or gene sharing) proteins.
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Affiliation(s)
- Marie-Lise Lacombe
- Sorbonne Université, UPMC Univ Paris 06, Paris, France. .,INSERM UMR-S 938, Saint-Antoine Research Center, Paris, France.
| | - Malgorzata Tokarska-Schlattner
- Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), University Grenoble Alpes, Grenoble, France.,Inserm U1055, Grenoble, France
| | - Mathieu Boissan
- Sorbonne Université, UPMC Univ Paris 06, Paris, France.,INSERM UMR-S 938, Saint-Antoine Research Center, Paris, France.,AP-HP, Hôpital Tenon, Service de Biochimie et Hormonologie, Paris, 75020, France
| | - Uwe Schlattner
- Laboratory of Fundamental and Applied Bioenergetics (LBFA), and SFR Environmental and Systems Biology (BEeSy), University Grenoble Alpes, Grenoble, France.,Inserm U1055, Grenoble, France
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23
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Molecular signature pathway of gene protein interaction in human mitochondrial DNA (mtDNA) metabolism linked disease. INDIAN JOURNAL OF MEDICAL SPECIALITIES 2018. [DOI: 10.1016/j.injms.2018.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Maalej M, Tej A, Bouguila J, Tilouche S, Majdoub S, Khabou B, Tabbebi M, Felhi R, Ammar M, Mkaouar-Rebai E, Keskes L, Boughamoura L, Fakhfakh F. Clinical, Molecular, and Computational Analysis in two cases with mitochondrial encephalomyopathy associated with SUCLG1 mutation in a consanguineous family. Biochem Biophys Res Commun 2017; 495:1730-1737. [PMID: 29217198 DOI: 10.1016/j.bbrc.2017.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 12/02/2017] [Indexed: 11/28/2022]
Abstract
Deficiency of the mitochondrial enzyme succinyl COA ligase (SUCL) is associated with encephalomyopathic mtDNA depletion syndrome and methylmalonic aciduria. This disorder is caused by mutations in both SUCL subunits genes: SUCLG1 (α subnit) and SUCLA2 (β subnit). We report here, two Tunisian patients belonging to a consanguineous family with mitochondrial encephalomyopathy, hearing loss, lactic acidosis, hypotonia, psychomotor retardation and methylmalonic aciduria. Mutational analysis of SUCLG1 gene showed, for the first time, the presence of c.41T > C in the exon 1 at homozygous state. In-silico analysis revealed that this mutation substitutes a conserved methionine residue to a threonine at position 14 (p.M14T) located at the SUCLG1 protein mitochondrial targeting sequence. Moreover, these analysis predicted that this mutation alter stability structure and mitochondrial translocation of the protein. In Addition, a decrease in mtDNA copy number was revealed by real time PCR in the peripheral blood leukocytes in the two patients compared with controls.
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Affiliation(s)
- Marwa Maalej
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia; Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia.
| | - Amel Tej
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Jihène Bouguila
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Samia Tilouche
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Senda Majdoub
- Service de Radiologie, CHU Farhat Hached, Sousse, University of Sousse, Tunisia
| | - Boudour Khabou
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Mouna Tabbebi
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Rahma Felhi
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Marwa Ammar
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Emna Mkaouar-Rebai
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia
| | - Leila Keskes
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Tunisia
| | - Lamia Boughamoura
- Service de pédiatrie, C.H.U. Farhat Hachad de sousse, University of Sousse, Tunisia
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Science of Sfax, University of Sfax, Tunisia.
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25
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Huang X, Bedoyan JK, Demirbas D, Harris DJ, Miron A, Edelheit S, Grahame G, DeBrosse SD, Wong LJ, Hoppel CL, Kerr DS, Anselm I, Berry GT. Succinyl-CoA synthetase (SUCLA2) deficiency in two siblings with impaired activity of other mitochondrial oxidative enzymes in skeletal muscle without mitochondrial DNA depletion. Mol Genet Metab 2017; 120:213-222. [PMID: 27913098 PMCID: PMC5346465 DOI: 10.1016/j.ymgme.2016.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 12/18/2022]
Abstract
Mutations in SUCLA2 result in succinyl-CoA ligase (ATP-forming) or succinyl-CoA synthetase (ADP-forming) (A-SCS) deficiency, a mitochondrial tricarboxylic acid cycle disorder. The phenotype associated with this gene defect is largely encephalomyopathy. We describe two siblings compound heterozygous for SUCLA2 mutations, c.985A>G (p.M329V) and c.920C>T (p.A307V), with parents confirmed as carriers of each mutation. We developed a new LC-MS/MS based enzyme assay to demonstrate the decreased SCS activity in the siblings with this unique genotype. Both siblings shared bilateral progressive hearing loss, encephalopathy, global developmental delay, generalized myopathy, and dystonia with choreoathetosis. Prior to diagnosis and because of lactic acidosis and low activity of muscle pyruvate dehydrogenase complex (PDC), sibling 1 (S1) was placed on dichloroacetate, while sibling 2 (S2) was on a ketogenic diet. S1 developed severe cyclic vomiting refractory to therapy, while S2 developed Leigh syndrome, severe GI dysmotility, intermittent anemia, hypogammaglobulinemia and eventually succumbed to his disorder. The mitochondrial DNA contents in skeletal muscle (SM) were normal in both siblings. Pyruvate dehydrogenase complex, ketoglutarate dehydrogenase complex, and several mitochondrial electron transport chain (ETC) activities were low or at the low end of the reference range in frozen SM from S1 and/or S2. In contrast, activities of PDC, other mitochondrial enzymes of pyruvate metabolism, ETC and, integrated oxidative phosphorylation, in skin fibroblasts were not significantly impaired. Although we show that propionyl-CoA inhibits PDC, it does not appear to account for decreased PDC activity in SM. A better understanding of the mechanisms of phenotypic variability and the etiology for tissue-specific secondary deficiencies of mitochondrial enzymes of oxidative metabolism, and independently mitochondrial DNA depletion (common in other cases of A-SCS deficiency), is needed given the implications for control of lactic acidosis and possible clinical management.
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Affiliation(s)
- Xiaoping Huang
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA
| | - Jirair K Bedoyan
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA; Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Didem Demirbas
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA
| | - David J Harris
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Alexander Miron
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Simone Edelheit
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - George Grahame
- Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA
| | - Suzanne D DeBrosse
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Charles L Hoppel
- Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA; Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Douglas S Kerr
- Center for Inherited Disorders of Energy Metabolism (CIDEM), University Hospitals Cleveland Medical Center, Cleveland, OH, USA; Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Irina Anselm
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - Gerard T Berry
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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26
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El-Hattab AW, Craigen WJ, Scaglia F. Mitochondrial DNA maintenance defects. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1539-1555. [PMID: 28215579 DOI: 10.1016/j.bbadis.2017.02.017] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/31/2017] [Accepted: 02/14/2017] [Indexed: 01/12/2023]
Abstract
The maintenance of mitochondrial DNA (mtDNA) depends on a number of nuclear gene-encoded proteins including a battery of enzymes forming the replisome needed to synthesize mtDNA. These enzymes need to be in balanced quantities to function properly that is in part achieved by exchanging intramitochondrial contents through mitochondrial fusion. In addition, mtDNA synthesis requires a balanced supply of nucleotides that is achieved by nucleotide recycling inside the mitochondria and import from the cytosol. Mitochondrial DNA maintenance defects (MDMDs) are a group of diseases caused by pathogenic variants in the nuclear genes involved in mtDNA maintenance resulting in impaired mtDNA synthesis leading to quantitative (mtDNA depletion) and qualitative (multiple mtDNA deletions) defects in mtDNA. Defective mtDNA leads to organ dysfunction due to insufficient mtDNA-encoded protein synthesis, resulting in an inadequate energy production to meet the needs of affected organs. MDMDs are inherited as autosomal recessive or dominant traits, and are associated with a broad phenotypic spectrum ranging from mild adult-onset ophthalmoplegia to severe infantile fatal hepatic failure. To date, pathogenic variants in 20 nuclear genes known to be crucial for mtDNA maintenance have been linked to MDMDs, including genes encoding enzymes of mtDNA replication machinery (POLG, POLG2, TWNK, TFAM, RNASEH1, MGME1, and DNA2), genes encoding proteins that function in maintaining a balanced mitochondrial nucleotide pool (TK2, DGUOK, SUCLG1, SUCLA2, ABAT, RRM2B, TYMP, SLC25A4, AGK, and MPV17), and genes encoding proteins involved in mitochondrial fusion (OPA1, MFN2, and FBXL4).
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Affiliation(s)
- Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatrics Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Fernando Scaglia
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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27
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Two transgenic mouse models for β-subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations. Biochem J 2016; 473:3463-3485. [PMID: 27496549 PMCID: PMC5126846 DOI: 10.1042/bcj20160594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/05/2016] [Indexed: 12/14/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer enzyme composed of Suclg1 α-subunit and a substrate-specific Sucla2 or Suclg2 β-subunit yielding ATP or GTP, respectively. In humans, the deficiency of this enzyme leads to encephalomyopathy with or without methylmalonyl aciduria, in addition to resulting in mitochondrial DNA depletion. We generated mice lacking either one Sucla2 or Suclg2 allele. Sucla2 heterozygote mice exhibited tissue- and age-dependent decreases in Sucla2 expression associated with decreases in ATP-forming activity, but rebound increases in cardiac Suclg2 expression and GTP-forming activity. Bioenergetic parameters including substrate-level phosphorylation (SLP) were not different between wild-type and Sucla2 heterozygote mice unless a submaximal pharmacological inhibition of SUCL was concomitantly present. mtDNA contents were moderately decreased, but blood carnitine esters were significantly elevated. Suclg2 heterozygote mice exhibited decreases in Suclg2 expression but no rebound increases in Sucla2 expression or changes in bioenergetic parameters. Surprisingly, deletion of one Suclg2 allele in Sucla2 heterozygote mice still led to a rebound but protracted increase in Suclg2 expression, yielding double heterozygote mice with no alterations in GTP-forming activity or SLP, but more pronounced changes in mtDNA content and blood carnitine esters, and an increase in succinate dehydrogenase activity. We conclude that a partial reduction in Sucla2 elicits rebound increases in Suclg2 expression, which is sufficiently dominant to overcome even a concomitant deletion of one Suclg2 allele, pleiotropically affecting metabolic pathways associated with SUCL. These results as well as the availability of the transgenic mouse colonies will be of value in understanding SUCL deficiency.
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28
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Besse A, Wu P, Bruni F, Donti T, Graham BH, Craigen WJ, McFarland R, Moretti P, Lalani S, Scott KL, Taylor RW, Bonnen PE. The GABA transaminase, ABAT, is essential for mitochondrial nucleoside metabolism. Cell Metab 2015; 21:417-27. [PMID: 25738457 PMCID: PMC4757431 DOI: 10.1016/j.cmet.2015.02.008] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/18/2014] [Accepted: 02/06/2015] [Indexed: 01/12/2023]
Abstract
ABAT is a key enzyme responsible for catabolism of principal inhibitory neurotransmitter γ-aminobutyric acid (GABA). We report an essential role for ABAT in a seemingly unrelated pathway, mitochondrial nucleoside salvage, and demonstrate that mutations in this enzyme cause an autosomal recessive neurometabolic disorder and mtDNA depletion syndrome (MDS). We describe a family with encephalomyopathic MDS caused by a homozygous missense mutation in ABAT that results in elevated GABA in subjects' brains as well as decreased mtDNA levels in subjects' fibroblasts. Nucleoside rescue and co-IP experiments pinpoint that ABAT functions in the mitochondrial nucleoside salvage pathway to facilitate conversion of dNDPs to dNTPs. Pharmacological inhibition of ABAT through the irreversible inhibitor Vigabatrin caused depletion of mtDNA in photoreceptor cells that was prevented through addition of dNTPs in cell culture media. This work reveals ABAT as a connection between GABA metabolism and nucleoside metabolism and defines a neurometabolic disorder that includes MDS.
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Affiliation(s)
- Arnaud Besse
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ping Wu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Francesco Bruni
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Taraka Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Paolo Moretti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Seema Lalani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kenneth L Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA.
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29
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Localization of SUCLA2 and SUCLG2 subunits of succinyl CoA ligase within the cerebral cortex suggests the absence of matrix substrate-level phosphorylation in glial cells of the human brain. J Bioenerg Biomembr 2014; 47:33-41. [PMID: 25370487 DOI: 10.1007/s10863-014-9586-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/21/2014] [Indexed: 10/24/2022]
Abstract
We have recently shown that the ATP-forming SUCLA2 subunit of succinyl-CoA ligase, an enzyme of the citric acid cycle, is exclusively expressed in neurons of the human cerebral cortex; GFAP- and S100-positive astroglial cells did not exhibit immunohistoreactivity or in situ hybridization reactivity for either SUCLA2 or the GTP-forming SUCLG2. However, Western blotting of post mortem samples revealed a minor SUCLG2 immunoreactivity. In the present work we sought to identify the cell type(s) harboring SUCLG2 in paraformaldehyde-fixed, free-floating surgical human cortical tissue samples. Specificity of SUCLG2 antiserum was supported by co-localization with mitotracker orange staining of paraformaldehyde-fixed human fibroblast cultures, delineating the mitochondrial network. In human cortical tissue samples, microglia and oligodendroglia were identified by antibodies directed against Iba1 and myelin basic protein, respectively. Double immunofluorescence for SUCLG2 and Iba1 or myelin basic protein exhibited no co-staining; instead, SUCLG2 appeared to outline the cerebral microvasculature. In accordance to our previous work there was no co-localization of SUCLA2 immunoreactivity with either Iba1 or myelin basic protein. We conclude that SUCLG2 exist only in cells forming the vasculature or its contents in the human brain. The absence of SUCLA2 and SUCLG2 in human glia is in compliance with the presence of alternative pathways occurring in these cells, namely the GABA shunt and ketone body metabolism which do not require succinyl CoA ligase activity, and glutamate dehydrogenase 1, an enzyme exhibiting exquisite sensitivity to inhibition by GTP.
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30
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Landsverk ML, Zhang VW, Wong LJC, Andersson HC. A SUCLG1 mutation in a patient with mitochondrial DNA depletion and congenital anomalies. Mol Genet Metab Rep 2014; 1:451-454. [PMID: 27896121 PMCID: PMC5121340 DOI: 10.1016/j.ymgmr.2014.09.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/25/2014] [Accepted: 09/25/2014] [Indexed: 02/05/2023] Open
Abstract
Defects in two subunits of succinate-CoA ligase encoded by the genes SUCLG1 and SUCLA2 have been identified in mitochondrial DNA (mtDNA) depletion syndromes. Patients generally present with encephalomyopathy and mild methylmalonic acidemia (MMA), however mutations in SUCLG1 normally appear to result in a more severe clinical phenotype. In this report, we describe a patient with fatal infantile lactic acidosis and multiple congenital anomalies (MCAs) including renal and cardiac defects. Molecular studies showed a defective electron transport chain (ETC), mtDNA depletion, and a novel homozygous mutation in the SUCLG1 gene. Although our patient's clinical biochemical phenotype is consistent with a SUCLG1 mutation, it is unclear whether the MCAs observed in our patient are a result of the SUCLG1 mutation or alterations in a second gene. An increasing number of reports have described MCAs associated with mitochondrial disorders and SUCLG1 specifically. Additional studies such as whole exome sequencing will further define whether additional genes are responsible for the observed MCAs.
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Affiliation(s)
- Megan L Landsverk
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Sanford Health, Sioux Falls, SD, USA
| | - Victor Wei Zhang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Hans C Andersson
- Hayward Genetics Center, Tulane University, New Orleans, LA, USA; Department of Pediatrics, Tulane University, New Orleans, LA, USA
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Different effects of guanine nucleotides (GDP and GTP) on protein-mediated mitochondrial proton leak. PLoS One 2014; 9:e98969. [PMID: 24904988 PMCID: PMC4056835 DOI: 10.1371/journal.pone.0098969] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 05/08/2014] [Indexed: 11/19/2022] Open
Abstract
In this study, we compared the influence of GDP and GTP on isolated mitochondria respiring under conditions favoring oxidative phosphorylation (OXPHOS) and under conditions excluding this process, i.e., in the presence of carboxyatractyloside, an adenine nucleotide translocase inhibitor, and/or oligomycin, an FOF1-ATP synthase inhibitor. Using mitochondria isolated from rat kidney and human endothelial cells, we found that the action of GDP and GTP can differ diametrically depending on the conditions. Namely, under conditions favoring OXPHOS, both in the absence and presence of linoleic acid, an activator of uncoupling proteins (UCPs), the addition of 1 mM GDP resulted in the state 4 (non-phosphorylating respiration)-state 3 (phosphorylating respiration) transition, which is characteristic of ADP oxidative phosphorylation. In contrast, the addition of 1 mM GTP resulted in a decrease in the respiratory rate and an increase in the membrane potential, which is characteristic of UCP inhibition. The stimulatory effect of GDP, but not GTP, was also observed in inside-out submitochondrial particles prepared from rat kidney mitochondria. However, the effects of GDP and GTP were more similar in the presence of OXPHOS inhibitors. The importance of these observations in connection with the action of UCPs, adenine nucleotide translocase (or other carboxyatractyloside-sensitive carriers), carboxyatractyloside- and purine nucleotide-insensitive carriers, as well as nucleoside-diphosphate kinase (NDPK) are considered. Because the measurements favoring oxidative phosphorylation better reflect in vivo conditions, our study strongly supports the idea that GDP cannot be considered a significant physiological inhibitor of UCP. Moreover, it appears that, under native conditions, GTP functions as a more efficient UCP inhibitor than GDP and ATP.
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Luís PBM, Ruiter J, IJlst L, de Almeida IT, Duran M, Wanders RJA, Silva MFB. Valproyl-CoA inhibits the activity of ATP- and GTP-dependent succinate:CoA ligases. J Inherit Metab Dis 2014; 37:353-7. [PMID: 24154984 DOI: 10.1007/s10545-013-9657-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/23/2013] [Accepted: 09/26/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Valproic acid (VPA) is an effective antiepileptic drug that may induce progressive microvesicular steatosis. The impairment of mitochondrial function may be an important metabolic effect of VPA treatment with potential adverse consequences. OBJECTIVE To investigate the influence of VPA on the activity of GTP- and ATP-specific succinate:CoA ligases (G-SUCL and A-SUCL). METHODS The GTP- and ATP-specific SUCL activities were measured in human fibroblasts in the reverse direction, i.e. the formation of succinyl-CoA. These were assessed at different concentrations of succinate in the presence of VPA, valproyl-CoA and zinc chloride, an established inhibitor of the enzymes. Activities were measured using an optimized HPLC procedure. RESULTS Valproyl-CoA (1 mM) inhibited the activity of A-SUCL and G-SUCL by 45-55% and 25-50%, respectively. VPA (1 mM) had no influence on the activity of the two enzymes. DISCUSSION Valproyl-CoA appears to affect the activity of SUCL, especially with the ATP-specific enzyme. Considering the key role of SUCL in the Krebs cycle, interference with its activity might impair the cellular energy status. Moreover, A-SUCL is bound to the nucleoside diphosphate kinase (NDPK), which is responsible for the mitochondrial (deoxy)nucleotide synthesis. An inhibition of A-SUCL might influence the activity of NDPK inducing an imbalance of nucleotides in the mitochondria and eventually mitochondrial DNA depletion. This may account for the potential liver failure associated with valproate therapy, reported in patients with deficiencies within the mitochondrial DNA replicase system such as polymerase gamma 1.
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Affiliation(s)
- Paula B M Luís
- Research Institute for Medicines and Pharmaceutical Sciences - iMED.UL, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003, Lisboa, Portugal
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Stark R, Kibbey RG. The mitochondrial isoform of phosphoenolpyruvate carboxykinase (PEPCK-M) and glucose homeostasis: has it been overlooked? BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1840:1313-30. [PMID: 24177027 PMCID: PMC3943549 DOI: 10.1016/j.bbagen.2013.10.033] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/13/2013] [Accepted: 10/18/2013] [Indexed: 01/03/2023]
Abstract
BACKGROUND Plasma glucose levels are tightly regulated within a narrow physiologic range. Insulin-mediated glucose uptake by tissues must be balanced by the appearance of glucose from nutritional sources, glycogen stores, or gluconeogenesis. In this regard, a common pathway regulating both glucose clearance and appearance has not been described. The metabolism of glucose to produce ATP is generally considered to be the primary stimulus for insulin release from beta-cells. Similarly, gluconeogenesis from phosphoenolpyruvate (PEP) is believed to be the primarily pathway via the cytosolic isoform of phosphoenolpyruvate carboxykinase (PEPCK-C). These models cannot adequately explain the regulation of insulin secretion or gluconeogenesis. SCOPE OF REVIEW A metabolic sensing pathway involving mitochondrial GTP (mtGTP) and PEP synthesis by the mitochondrial isoform of PEPCK (PEPCK-M) is associated with glucose-stimulated insulin secretion from pancreatic beta-cells. Here we examine whether there is evidence for a similar mtGTP-dependent pathway involved in gluconeogenesis. In both islets and the liver, mtGTP is produced at the substrate level by the enzyme succinyl CoA synthetase (SCS-GTP) with a rate proportional to the TCA cycle. In the beta-cell PEPCK-M then hydrolyzes mtGTP in the production of PEP that, unlike mtGTP, can escape the mitochondria to generate a signal for insulin release. Similarly, PEPCK-M and mtGTP might also provide a significant source of PEP in gluconeogenic tissues for the production of glucose. This review will focus on the possibility that PEPCK-M, as a sensor for TCA cycle flux, is a key mechanism to regulate both insulin secretion and gluconeogenesis suggesting conservation of this biochemical mechanism in regulating multiple aspects of glucose homeostasis. Moreover, we propose that this mechanism may be important for regulating insulin secretion and gluconeogenesis compared to canonical nutrient sensing pathways. MAJOR CONCLUSIONS PEPCK-M, initially believed to be absent in islets, carries a substantial metabolic flux in beta-cells. This flux is intimately involved with the coupling of glucose-stimulated insulin secretion. PEPCK-M activity may have been similarly underestimated in glucose producing tissues and could potentially be an unappreciated but important source of gluconeogenesis. GENERAL SIGNIFICANCE The generation of PEP via PEPCK-M may occur via a metabolic sensing pathway important for regulating both insulin secretion and gluconeogenesis. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Romana Stark
- Department of Physiology, Monash University, Clayton, Victoria 3800, Australia.
| | - Richard G Kibbey
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8020, USA.
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Donti TR, Stromberger C, Ge M, Eldin KW, Craigen WJ, Graham BH. Screen for abnormal mitochondrial phenotypes in mouse embryonic stem cells identifies a model for succinyl-CoA ligase deficiency and mtDNA depletion. Dis Model Mech 2014; 7:271-80. [PMID: 24271779 PMCID: PMC3917248 DOI: 10.1242/dmm.013466] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/18/2013] [Indexed: 12/12/2022] Open
Abstract
Mutations in subunits of succinyl-CoA synthetase/ligase (SCS), a component of the citric acid cycle, are associated with mitochondrial encephalomyopathy, elevation of methylmalonic acid (MMA), and mitochondrial DNA (mtDNA) depletion. A FACS-based retroviral-mediated gene trap mutagenesis screen in mouse embryonic stem (ES) cells for abnormal mitochondrial phenotypes identified a gene trap allele of Sucla2 (Sucla2(SAβgeo)), which was used to generate transgenic mice. Sucla2 encodes the ADP-specific β-subunit isoform of SCS. Sucla2(SAβgeo) homozygotes exhibited recessive lethality, with most mutants dying late in gestation (e18.5). Mutant placenta and embryonic (e17.5) brain, heart and muscle showed varying degrees of mtDNA depletion (20-60%). However, there was no mtDNA depletion in mutant liver, where the gene is not normally expressed. Elevated levels of MMA were observed in embryonic brain. SCS-deficient mouse embryonic fibroblasts (MEFs) demonstrated a 50% reduction in mtDNA content compared with wild-type MEFs. The mtDNA depletion resulted in reduced steady state levels of mtDNA encoded proteins and multiple respiratory chain deficiencies. mtDNA content could be restored by reintroduction of Sucla2. This mouse model of SCS deficiency and mtDNA depletion promises to provide insights into the pathogenesis of mitochondrial diseases with mtDNA depletion and into the biology of mtDNA maintenance. In addition, this report demonstrates the power of a genetic screen that combines gene trap mutagenesis and FACS analysis in mouse ES cells to identify mitochondrial phenotypes and to develop animal models of mitochondrial dysfunction.
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Affiliation(s)
- Taraka R. Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Carmen Stromberger
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Ming Ge
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Karen W. Eldin
- Department of Pathology and Immunology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - William J. Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Dobolyi A, Ostergaard E, Bagó AG, Dóczi T, Palkovits M, Gál A, Molnár MJ, Adam-Vizi V, Chinopoulos C. Exclusive neuronal expression of SUCLA2 in the human brain. Brain Struct Funct 2013; 220:135-51. [PMID: 24085565 DOI: 10.1007/s00429-013-0643-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/18/2013] [Indexed: 11/24/2022]
Abstract
SUCLA2 encodes the ATP-forming β subunit (A-SUCL-β) of succinyl-CoA ligase, an enzyme of the citric acid cycle. Mutations in SUCLA2 lead to a mitochondrial disorder manifesting as encephalomyopathy with dystonia, deafness and lesions in the basal ganglia. Despite the distinct brain pathology associated with SUCLA2 mutations, the precise localization of SUCLA2 protein has never been investigated. Here, we show that immunoreactivity of A-SUCL-β in surgical human cortical tissue samples was present exclusively in neurons, identified by their morphology and visualized by double labeling with a fluorescent Nissl dye. A-SUCL-β immunoreactivity co-localized >99 % with that of the d subunit of the mitochondrial F0-F1 ATP synthase. Specificity of the anti-A-SUCL-β antiserum was verified by the absence of labeling in fibroblasts from a patient with a complete deletion of SUCLA2. A-SUCL-β immunoreactivity was absent in glial cells, identified by antibodies directed against the glial markers GFAP and S100. Furthermore, in situ hybridization histochemistry demonstrated that SUCLA2 mRNA was present in Nissl-labeled neurons but not glial cells labeled with S100. Immunoreactivity of the GTP-forming β subunit (G-SUCL-β) encoded by SUCLG2, or in situ hybridization histochemistry for SUCLG2 mRNA could not be demonstrated in either neurons or astrocytes. Western blotting of post mortem brain samples revealed minor G-SUCL-β immunoreactivity that was, however, not upregulated in samples obtained from diabetic versus non-diabetic patients, as has been described for murine brain. Our work establishes that SUCLA2 is expressed exclusively in neurons in the human cerebral cortex.
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Affiliation(s)
- Arpád Dobolyi
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, 1094, Hungary
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36
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Veluthakal R, Kaetzel D, Kowluru A. Nm23-H1 regulates glucose-stimulated insulin secretion in pancreatic β-cells via Arf6-Rac1 signaling axis. Cell Physiol Biochem 2013; 32:533-41. [PMID: 24008651 DOI: 10.1159/000354457] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND A growing body of evidence implicates novel roles for nm23-like proteins in the regulation of cellular functions. However, roles of these proteins in islet function and glucose-stimulated insulin secretion (GSIS) remain largely unknown. METHODS siRNA-nm23-H1 and nucleoside diphosphate kinase and histidine kinase-deficient mutants of nm23-H1 (K12Q and H118F) were used to assess roles of nm23-H1 in GSIS. RESULTS siRNA-mediated knockdown of the expression of nm23-H1 markedly inhibited GSIS in INS-1 832/13 cells. Nm23-H1 knockdown also resulted in significant inhibition of glucose-mediated activation of Arf6, a small G-protein, which has been implicated in GSIS. Expression of K12Q and H118F mutants of nm23-H1 in INS-1 832/13 cells led to inhibition of glucose-induced translocation and membrane association of Rac1, another small G-protein, which is downstream to Arf6 in the signaling events leading to GSIS. A significant inhibition of GSIS was also seen in these cells expressing K12Q and H118F. CONCLUSIONS We conclude that the nm23-H1 activation step is upstream of Arf6 activation in signaling events leading to GSIS. NDP kinase and histidine kinase functions of nm23-H1 are necessary for glucose-induced membrane association of Rac1 and ensuing insulin secretion. We present the first evidence for regulation of GSIS by nm23-H1 in pancreatic β-cells.
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37
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The novel mutation p.Asp251Asn in the β-subunit of succinate-CoA ligase causes encephalomyopathy and elevated succinylcarnitine. J Hum Genet 2013; 58:526-30. [DOI: 10.1038/jhg.2013.45] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/08/2013] [Accepted: 04/13/2013] [Indexed: 02/08/2023]
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38
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Huang S, Jacoby RP, Shingaki-Wells RN, Li L, Millar AH. Differential induction of mitochondrial machinery by light intensity correlates with changes in respiratory metabolism and photorespiration in rice leaves. THE NEW PHYTOLOGIST 2013; 198:103-115. [PMID: 23356873 DOI: 10.1111/nph.12123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/27/2012] [Indexed: 05/04/2023]
Abstract
The light responsiveness of mitochondrial function was investigated through changes in mitochondrial composition and metabolism in rice (Oryza sativa) shoots. The mitochondrial proteome and metabolite abundances under low light, (LL, 100 μmol m(-2) s(-1) ), and high light (HL, 700 μmol m(-2) s(-1) ) were measured along with information on shoot photosynthetic, respiratory and photorespiratory activity. Specific steps in mitochondrial tricarboxylic acid (TCA) cycle metabolism were decreased under HL, correlating with lower respiration rate under HL. The abundance of mitochondrial enzymes in branch chain metabolism was reduced under HL/LL, and correlated with a decrease in the abundance of a range of amino acids in the HL/LL. Mitochondrial nucleoside diphosphate kinase was increased under LL/HL treatments. Significant accumulation of glycine decarboxylase P, T subunits and serine hydroxymethyltransferase occurred in response to light. The abundance of the glycine decarboxylase (GDC) H subunit proteins was not changed by HL/LL treatments, and the abundance of GDC L subunit protein was halved under HL, indicating a change in the stoichiometry of GDC subunits, while photorespiration was fourfold higher in LL- than in HL-treated plants. Insights into these light-dependent phenomena and their importance for understanding the initiation of photorespiration in rice and adaptation of mitochondria to function in photosynthetic cells are discussed.
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Affiliation(s)
- Shaobai Huang
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Richard P Jacoby
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Rachel N Shingaki-Wells
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Lei Li
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - A Harvey Millar
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
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39
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Huang S, Jacoby RP, Shingaki-Wells RN, Li L, Millar AH. Differential induction of mitochondrial machinery by light intensity correlates with changes in respiratory metabolism and photorespiration in rice leaves. THE NEW PHYTOLOGIST 2013. [PMID: 23356873 DOI: 10.1111/nph.12123 [epub ahead of print]] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The light responsiveness of mitochondrial function was investigated through changes in mitochondrial composition and metabolism in rice (Oryza sativa) shoots. The mitochondrial proteome and metabolite abundances under low light, (LL, 100 μmol m(-2) s(-1) ), and high light (HL, 700 μmol m(-2) s(-1) ) were measured along with information on shoot photosynthetic, respiratory and photorespiratory activity. Specific steps in mitochondrial tricarboxylic acid (TCA) cycle metabolism were decreased under HL, correlating with lower respiration rate under HL. The abundance of mitochondrial enzymes in branch chain metabolism was reduced under HL/LL, and correlated with a decrease in the abundance of a range of amino acids in the HL/LL. Mitochondrial nucleoside diphosphate kinase was increased under LL/HL treatments. Significant accumulation of glycine decarboxylase P, T subunits and serine hydroxymethyltransferase occurred in response to light. The abundance of the glycine decarboxylase (GDC) H subunit proteins was not changed by HL/LL treatments, and the abundance of GDC L subunit protein was halved under HL, indicating a change in the stoichiometry of GDC subunits, while photorespiration was fourfold higher in LL- than in HL-treated plants. Insights into these light-dependent phenomena and their importance for understanding the initiation of photorespiration in rice and adaptation of mitochondria to function in photosynthetic cells are discussed.
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Affiliation(s)
- Shaobai Huang
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Richard P Jacoby
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Rachel N Shingaki-Wells
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Lei Li
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - A Harvey Millar
- ARC Centre of Excellence in Plant Energy Biology and Centre for Comparative Analysis of Biomolecular Networks (CABiN), The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, WA, 6009, Australia
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El-Hattab AW, Scaglia F. Mitochondrial DNA depletion syndromes: review and updates of genetic basis, manifestations, and therapeutic options. Neurotherapeutics 2013; 10:186-98. [PMID: 23385875 PMCID: PMC3625391 DOI: 10.1007/s13311-013-0177-6] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are a genetically and clinically heterogeneous group of autosomal recessive disorders that are characterized by a severe reduction in mtDNA content leading to impaired energy production in affected tissues and organs. MDS are due to defects in mtDNA maintenance caused by mutations in nuclear genes that function in either mitochondrial nucleotide synthesis (TK2, SUCLA2, SUCLG1, RRM2B, DGUOK, and TYMP) or mtDNA replication (POLG and C10orf2). MDS are phenotypically heterogeneous and usually classified as myopathic, encephalomyopathic, hepatocerebral or neurogastrointestinal. Myopathic MDS, caused by mutations in TK2, usually present before the age of 2 years with hypotonia and muscle weakness. Encephalomyopathic MDS, caused by mutations in SUCLA2, SUCLG1, or RRM2B, typically present during infancy with hypotonia and pronounced neurological features. Hepatocerebral MDS, caused by mutations in DGUOK, MPV17, POLG, or C10orf2, commonly have an early-onset liver dysfunction and neurological involvement. Finally, TYMP mutations have been associated with mitochondrial neurogastrointestinal encephalopathy (MNGIE) disease that typically presents before the age of 20 years with progressive gastrointestinal dysmotility and peripheral neuropathy. Overall, MDS are severe disorders with poor prognosis in the majority of affected individuals. No efficacious therapy is available for any of these disorders. Affected individuals should have a comprehensive evaluation to assess the degree of involvement of different systems. Treatment is directed mainly toward providing symptomatic management. Nutritional modulation and cofactor supplementation may be beneficial. Liver transplantation remains controversial. Finally, stem cell transplantation in MNGIE disease shows promising results.
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Affiliation(s)
- Ayman W. El-Hattab
- />Division of Medical Genetics, Department of Pediatrics, The Children’s Hospital, King Fahad Medical City and Faculty of Medicine, King Saud bin Abdulaziz University for Health Science, Riyadh, Kingdom of Saudi Arabia
| | - Fernando Scaglia
- />Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS BCM225, Houston, TX 77030 USA
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41
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Lipskaya TY, Voinova VV. Activity of nucleoside diphosphate kinase α (NDPK α) capable of binding to outer mitochondrial membrane accounts for less than 10% of total NDPK activity present in cytoplasm of liver cells. BIOCHEMISTRY (MOSCOW) 2012; 77:593-602. [PMID: 22817458 DOI: 10.1134/s0006297912060053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
During incubation of a constant volume of rat liver cytosol with an increasing quantity of mitochondrial protein in the presence of 3.3 mM MgCl(2), the binding of nucleoside diphosphate kinase (NDPK) from the cytosol to mitochondrial membranes is described by a saturation curve. The highest bound NDPK activity accounts for less than 9% of the added activity. Analysis of the results suggests that only one NDPK isozyme is bound to the membranes. Western blotting showed it to be NDPK α, a homolog of human NDPK-B. Substrates of NDPK, hexokinase, and glycerol kinase, as well as N,N'-dicyclohexylcarbodiimide and palmitate, did not influence the association of NDPK with mitochondrial membranes. We conclude that the sites of NDPK binding to the outer mitochondrial membrane are not identical to those of hexokinase and glycerol kinase.
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Affiliation(s)
- T Yu Lipskaya
- Department of Biochemistry, Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia.
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42
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Huypens PR, Huang M, Joseph JW. Overcoming the spatial barriers of the stimulus secretion cascade in pancreatic β-cells. Islets 2012; 4:1-116. [PMID: 22143007 DOI: 10.4161/isl.18338] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ability of the pancreatic β-cells to adapt the rate of insulin release in accordance to changes in circulating glucose levels is essential for glucose homeostasis. Two spatial barriers imposed by the plasma membrane and inner mitochondrial membrane need to be overcome in order to achieve stringent coupling between the different steps in the stimulus-secretion cascade. The first spatial barrier is overcome by the presence of a glucose transporter (GLUT) in the plasma membrane, whereas a low affinity hexokinase IV (glucokinase, GK) in the cytosol conveys glucose availability into a metabolic flux that triggers and accelerates insulin release. The mitochondrial inner membrane comprises a second spatial barrier that compartmentalizes glucose metabolism into glycolysis (cytosol) and tricarboxylate (TCA) cycle (mitochondrial matrix). The exchange of metabolites between cytosol and mitochondrial matrix is mediated via a set of mitochondrial carriers, including the aspartate-glutamate carrier (aralar1), α- ketoglutarate carrier (OGC), ATP/ADP carrier (AAC), glutamate carrier (GC1), dicarboxylate carrier (DIC) and citrate/isocitrate carrier (CIC). The scope of this review is to provide an overview of the role these carriers play in stimulus-secretion coupling and discuss the importance of these findings in the context of the exquisite glucose responsive state of the pancreatic β-cell.
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Affiliation(s)
- Peter R Huypens
- School of Pharmacy; Health Science Campus; University of Waterloo; Kitchener, CN Canada
| | - Mei Huang
- School of Pharmacy; Health Science Campus; University of Waterloo; Kitchener, CN Canada
| | - Jamie W Joseph
- School of Pharmacy; Health Science Campus; University of Waterloo; Kitchener, CN Canada
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43
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Spinazzola A. Mitochondrial DNA mutations and depletion in pediatric medicine. Semin Fetal Neonatal Med 2011; 16:190-6. [PMID: 21652274 DOI: 10.1016/j.siny.2011.04.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are a group of diseases traditionally ascribed to defects of the respiratory chain, which is the only metabolic pathway in the cell that is under the control of the two separate genetic systems, the mitochondrial genome (mtDNA) and the nuclear genome (nDNA). Therefore the genetic classification of the primary mitochondrial diseases distinguishes disorders due to mutations in mtDNA, which are sporadic or maternal inherited, from disorders due to mutations in nDNA, which are governed by the stricter rules of mendelian genetics. Pathological alterations of mtDNA fall into two main categories: primary mutations of mitochondrial DNA (point mutations and rearrangements) and mtDNA perturbation, due to mutations in nuclear genes whose products are involved in mtDNA maintenance or replication. This article will focus on the primary mitochondrial DNA mutations and mtDNA depletion syndromes related to neonatal-infant human pathology.
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Affiliation(s)
- A Spinazzola
- MRC, Mitochondrial Biology Unit, Wellcome Trust, MRC Building, Hills Road, Cambridge CB2 0XY, UK.
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Lipskaya TY, Voinova VV. Mitochondrial nucleoside diphosphate kinase: Mode of interaction with the outer mitochondrial membrane and proportion of catalytic activity functionally coupled to oxidative phosphorylation. BIOCHEMISTRY (MOSCOW) 2011; 73:321-31. [DOI: 10.1134/s0006297908030139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kowluru A, Klumpp S, Krieglstein J. Protein histidine [de]phosphorylation in insulin secretion: abnormalities in models of impaired insulin secretion. Naunyn Schmiedebergs Arch Pharmacol 2011; 384:383-90. [PMID: 21626002 DOI: 10.1007/s00210-011-0616-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 02/18/2011] [Indexed: 12/20/2022]
Abstract
In the majority of cell types, including the islet β-cell, transduction of extracellular signals involves ligand binding to a receptor, often followed by the activation G proteins and their effector modules. The islet β-cell is unusual in that glucose lacks an extracellular receptor. Instead, events consequent to glucose metabolism promote insulin secretion via the generation of diffusible second messengers and mobilization of calcium. A selective increase in intracellular calcium has been shown to regulate the phosphorylation status key islet proteins thereby facilitating insulin secretion. In addition to classical protein kinases [e.g., protein kinases A and C], recent studies from our laboratory have focused on the expression and function of various forms of NDPK/nm23-like histidine kinases in clonal β-cells, normal rodent, and human islets. Further, we recently reported localization of a cytosolic protein histidine phosphatase [PHP] in INS 832/13 cells, normal rat islets, and human islets. siRNA-mediated knock down of nm23-H1 and PHP in insulin-secreting INS 832/13 cells significantly attenuated glucose-induced insulin secretion. We also observed significant alterations in the expression and function of nm23-H1/PHP in β-cells chronically exposed to elevated levels of glucose and saturated fatty acids, such as palmitate (i.e., glucolipotoxicity). Similar changes were also noted in islets from the Goto-Kakizaki and Zucker Diabetic Fatty rats, two known models for type 2 diabetes. It is concluded that protein histidine phosphorylation-dephosphorylation cycles play novel regulatory roles in G protein-mediated physiological insulin secretion and that abnormalities in this signaling axis lead to impaired insulin secretion in glucolipotoxicity and type 2 diabetes.
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Affiliation(s)
- Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, John D. Dingell VA Medical Center, Detroit, MI 48201, USA.
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Miller C, Wang L, Ostergaard E, Dan P, Saada A. The interplay between SUCLA2, SUCLG2, and mitochondrial DNA depletion. Biochim Biophys Acta Mol Basis Dis 2011; 1812:625-9. [PMID: 21295139 DOI: 10.1016/j.bbadis.2011.01.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 01/22/2011] [Accepted: 01/26/2011] [Indexed: 11/24/2022]
Abstract
SUCLA2-related mitochondrial DNA (mtDNA) depletion syndrome is a result of mutations in the β subunit of the ADP-dependent isoform of the Krebs cycle succinyl-CoA synthase (SCS). The mechanism of tissue specificity and mtDNA depletion is elusive but complementation by the GDP-dependent isoform encoded by SUCLG2, and the association with mitochondrial nucleoside diphosphate kinase (NDPK), is a plausible link. We have investigated this relationship by studying SUCLA2 deficient fibroblasts derived from patients and detected normal mtDNA content and normal NDPK activity. However, knockdown of SUCLG2 by shRNA in both patient and control fibroblasts resulted in a significant decrease in mtDNA amount, decreased NDPK and cytochrome c oxidase activities, and a marked growth impairment. This suggests that, SUCLG2, to a higher degree than SUCLA2, is crucial for mtDNA maintenance and that mitochondrial NDPK is involved. Although results pertain to a cell culture system, the findings might explain the pathomechanism and tissue specificity in mtDNA depletion caused by defective SUCLA2.
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Affiliation(s)
- Chaya Miller
- Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, POB 1200, 91120 Jerusalem, Israel
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Van Hove JLK, Saenz MS, Thomas JA, Gallagher RC, Lovell MA, Fenton LZ, Shanske S, Myers SM, Wanders RJA, Ruiter J, Turkenburg M, Waterham HR. Succinyl-CoA ligase deficiency: a mitochondrial hepatoencephalomyopathy. Pediatr Res 2010; 68:159-64. [PMID: 20453710 PMCID: PMC2928220 DOI: 10.1203/pdr.0b013e3181e5c3a4] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This patient presented on the first day of life with pronounced lactic acidosis with an elevated lactate/pyruvate ratio. Urine organic acids showed Krebs cycle metabolites and mildly elevated methylmalonate and methylcitrate. The acylcarnitine profile showed elevated propionylcarnitine and succinylcarnitine. Amino acids showed elevated glutamic acid, glutamine, proline, and alanine. From the age 2 of mo on, she had elevated transaminases and intermittent episodes of liver failure. Liver biopsy showed steatosis and a decrease of mitochondrial DNA to 50% of control. She had bilateral sensorineural hearing loss. Over the course of the first 2 y of life, she developed a progressively severe myopathy with pronounced muscle weakness eventually leading to respiratory failure, Leigh disease, and recurrent hepatic failure. The hepatic symptoms and the metabolic parameters temporarily improved on treatment with aspartate, but neither muscle symptoms nor brain lesions improved. Laboratory testing revealed a deficiency of succinyl-CoA ligase enzyme activity and protein in fibroblasts because of a novel homozygous mutation in the SUCLG1 gene: c.40A>T (p.M14L). Functional analysis suggests that this methionine is more likely to function as the translation initiator methionine, explaining the pathogenic nature of the mutation. Succinyl-CoA ligase deficiency due to an SUCLG1 mutation is a new cause for mitochondrial hepatoencephalomyopathy.
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Affiliation(s)
- Johan L K Van Hove
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado 80045, USA.
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Abstract
Some cases of mitochondrial diseases are due to mitochondrial DNA instability: multiple deletions or depletions. These anomalies are responsible for a mitochondrial respiratory chain impairment leading to various clinical involvements ranging from mild features with multiple mtDNA deletions to severe organ failure and premature death caused by mtDNA depletions. Both, deletions and depletions share an important and common feature between these two specificities: indeed, both are expressed in a tissue-specific manner.
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Affiliation(s)
- Emmanuelle Sarzi
- Inserm U781, Hôpital Necker Enfants malades, 75015 Paris, France.
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Ostergaard E, Schwartz M, Batbayli M, Christensen E, Hjalmarson O, Kollberg G, Holme E. A novel missense mutation in SUCLG1 associated with mitochondrial DNA depletion, encephalomyopathic form, with methylmalonic aciduria. Eur J Pediatr 2010; 169:201-5. [PMID: 19526370 DOI: 10.1007/s00431-009-1007-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Accepted: 05/19/2009] [Indexed: 01/27/2023]
Abstract
Mitochondrial DNA depletion, encephalomyopathic form, with methylmalonic aciduria is associated with mutations in SUCLA2, the gene encoding a beta subunit of succinate-CoA ligase, where 17 patients have been reported. Mutations in SUCLG1, encoding the alpha subunit of the enzyme, have been reported in only one family, where a homozygous 2 bp deletion was associated with fatal infantile lactic acidosis. We here report a patient with a novel homozygous missense mutation in SUCLG1, whose phenotype is similar to that of patients with SUCLA2 mutations.
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Affiliation(s)
- Elsebet Ostergaard
- Department of Clinical Genetics 4062, National University Hospital Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark.
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Rötig A, Poulton J. Genetic causes of mitochondrial DNA depletion in humans. Biochim Biophys Acta Mol Basis Dis 2009; 1792:1103-8. [PMID: 19596444 DOI: 10.1016/j.bbadis.2009.06.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 06/19/2009] [Accepted: 06/24/2009] [Indexed: 11/16/2022]
Abstract
Mitochondrial DNA (mtDNA) depletion is characterized by a profound reduction of mtDNA copy number. The maintenance of mtDNA copy number requires several nuclear-encoded factors involved in replication and in dNTP supply. In the past decade mutations in several of these factors have been reported in a growing number of syndromes. This article reviews the current knowledge of genes causing mitochondrial DNA depletion syndromes.
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Affiliation(s)
- Agnès Rötig
- INSERM U781, Hôpital Necker-Enfants Malades, Université René Descartes Paris V, 149 rue de Sèvres, 75015 Paris, France.
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