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Gnimpieba E, Diing DM, Ailts J, Cucak A, Gakh O, Isaya G, Vitiello S, Wang S, Pierce P, Cooper A, Roux K, Rogers LK, Vitiello PF. Mapping Novel Frataxin Mitochondrial Networks Through Protein- Protein Interactions. RESEARCH SQUARE 2024:rs.3.rs-4259413. [PMID: 38746130 PMCID: PMC11092868 DOI: 10.21203/rs.3.rs-4259413/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Friedreich's Ataxia (FRDA) is a neuromuscular degenerative disorder caused by trinucleotide expansions in the first intron of the frataxin (FXN) gene, resulting in insufficient levels of functional FNX protein. Deficits in FXN involve mitochondrial disruptions including iron-sulfur cluster synthesis and impaired energetics. These studies were to identify unique protein-protein interactions with FXN to better understand its function and design therapeutics. Two complementary approaches were employed, BioID and Co-IP, to identify protein interactions with FXN at the direct binding, indirect binding, and non-proximal levels. Forty-one novel protein interactions were identified by BioID and IP techniques. The FXN protein landscape was further analyzed incorporating both interaction type and functional pathways using a maximum path of 6 proteins with a potential direct interaction between FXN and NFS1. Probing the intersection between FXN-protein landscape and biological pathways associated with FRDA, we identified 41 proteins of interest. Peroxiredoxin 3 (Prdx3) was chosen for further analysis because of its role in mitochondrial oxidative injury. Our data has demonstrated the strengths of employing complementary methods to identify a unique interactome for FXN. Our data provides new insights into FXN function and regulation, a potential direct interaction between FXN and NFS1, and pathway interactions between FXN and Prdx3.
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Affiliation(s)
| | | | - Jared Ailts
- University of South Dakota Sanford School of Medicine
| | | | | | | | | | | | - Paul Pierce
- University of Oklahoma Health Sciences Center
| | - Alec Cooper
- University of Oklahoma Health Sciences Center
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2
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Medina-Carbonero M, Sanz-Alcázar A, Britti E, Delaspre F, Cabiscol E, Ros J, Tamarit J. Mice harboring the FXN I151F pathological point mutation present decreased frataxin levels, a Friedreich ataxia-like phenotype, and mitochondrial alterations. Cell Mol Life Sci 2022; 79:74. [PMID: 35038030 PMCID: PMC8763788 DOI: 10.1007/s00018-021-04100-5] [Citation(s) in RCA: 6] [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: 05/25/2021] [Revised: 11/21/2021] [Accepted: 12/16/2021] [Indexed: 12/13/2022]
Abstract
Friedreich Ataxia (FA) is a rare neuro-cardiodegenerative disease caused by mutations in the frataxin (FXN) gene. The most prevalent mutation is a GAA expansion in the first intron of the gene causing decreased frataxin expression. Some patients present the GAA expansion in one allele and a missense mutation in the other allele. One of these mutations, FXNI154F, was reported to result in decreased content of mature frataxin and increased presence of an insoluble intermediate proteoform in cellular models. By introducing this mutation into the murine Fxn gene (I151F, equivalent to human I154F) we have now analyzed the consequences of this pathological point mutation in vivo. We have observed that FXNI151F homozygous mice present low frataxin levels in all tissues, with no evidence of insoluble proteoforms. Moreover, they display neurological deficits resembling those observed in FA patients. Biochemical analysis of heart, cerebrum and cerebellum have revealed decreased content of components from OXPHOS complexes I and II, decreased aconitase activity, and alterations in antioxidant defenses. These mitochondrial alterations are more marked in the nervous system than in heart, precede the appearance of neurological symptoms, and are similar to those observed in other FA models. We conclude that the primary pathological mechanism underlying the I151F mutation is frataxin deficiency, like in patients carrying GAA expansions. Therefore, patients carrying the I154F mutation would benefit from frataxin replacement therapies. Furthermore, our results also show that the FXNI151F mouse is an excellent tool for analyzing tissue-specific consequences of frataxin deficiency and for testing new therapies.
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Affiliation(s)
- Marta Medina-Carbonero
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Arabela Sanz-Alcázar
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Elena Britti
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Fabien Delaspre
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Elisa Cabiscol
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Joaquim Ros
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain
| | - Jordi Tamarit
- Dept. Ciències Mèdiques Bàsiques, Fac. Medicina, IRBLleida, Universitat de Lleida, Av. Rovira Roure, 80, 25198, Lleida, Spain.
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3
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SINEUPs: a novel toolbox for RNA therapeutics. Essays Biochem 2021; 65:775-789. [PMID: 34623427 PMCID: PMC8564737 DOI: 10.1042/ebc20200114] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/22/2021] [Accepted: 08/23/2021] [Indexed: 12/17/2022]
Abstract
RNA molecules have emerged as a new class of promising therapeutics to expand the range of druggable targets in the genome. In addition to ‘canonical’ protein-coding mRNAs, the emerging richness of sense and antisense long non-coding RNAs (lncRNAs) provides a new reservoir of molecular tools for RNA-based drugs. LncRNAs are composed of modular structural domains with specific activities involving the recruitment of protein cofactors or directly interacting with nucleic acids. A single therapeutic RNA transcript can then be assembled combining domains with defined secondary structures and functions, and antisense sequences specific for the RNA/DNA target of interest. As the first representative molecules of this new pharmacology, we have identified SINEUPs, a new functional class of natural antisense lncRNAs that increase the translation of partially overlapping mRNAs. Their activity is based on the combination of two domains: an embedded mouse inverted SINEB2 element that enhances mRNA translation (effector domain) and an overlapping antisense region that provides specificity for the target sense transcript (binding domain). By genetic engineering, synthetic SINEUPs can potentially target any mRNA of interest increasing translation and therefore the endogenous level of the encoded protein. In this review, we describe the state-of-the-art knowledge of SINEUPs and discuss recent publications showing their potential application in diseases where a physiological increase of endogenous protein expression can be therapeutic.
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4
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Ijomone OM, Ifenatuoha CW, Aluko OM, Ijomone OK, Aschner M. The aging brain: impact of heavy metal neurotoxicity. Crit Rev Toxicol 2020; 50:801-814. [PMID: 33210961 DOI: 10.1080/10408444.2020.1838441] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The aging process is accompanied by critical changes in cellular and molecular functions, which upset the homeostatic balance in the central nervous system. Accumulation of metals renders the brain susceptible to neurotoxic insults by mechanisms such as mitochondrial dysfunction, neuronal calcium-ion dyshomeostasis, buildup of damaged molecules, compromised DNA repair, reduction in neurogenesis, and impaired energy metabolism. These hallmarks have been identified to be responsible for neuronal injuries, resulting in several neurological disorders. Various studies have shown solid associations between metal accumulation, abnormal protein expressions, and pathogenesis of neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and Amyotrophic lateral sclerosis. This review highlights metals (such as manganese, zinc, iron, copper, and nickel) for their accumulation, and consequences in the development of neurological disorders, in relation to the aging brain.
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Affiliation(s)
- Omamuyovwi M Ijomone
- The Neuro-Lab, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria.,Department of Human Anatomy, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Chibuzor W Ifenatuoha
- The Neuro-Lab, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Oritoke M Aluko
- The Neuro-Lab, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria.,Department of Physiology, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria
| | - Olayemi K Ijomone
- The Neuro-Lab, School of Health and Health Technology, Federal University of Technology, Akure, Nigeria.,Department of Anatomy, University of Medical Sciences, Ondo, Nigeria
| | - Michael Aschner
- Departments of Molecular Pharmacology, Pediatrics and Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
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5
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Chiang S, Huang MLH, Richardson DR. Treatment of dilated cardiomyopathy in a mouse model of Friedreich's ataxia using N-acetylcysteine and identification of alterations in microRNA expression that could be involved in its pathogenesis. Pharmacol Res 2020; 159:104994. [PMID: 32534099 DOI: 10.1016/j.phrs.2020.104994] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/01/2020] [Accepted: 06/01/2020] [Indexed: 01/01/2023]
Abstract
Deficient expression of the mitochondrial protein, frataxin, leads to a deadly cardiomyopathy. Our laboratory reported the master regulator of oxidative stress, nuclear factor erythroid 2-related factor-2 (Nrf2), demonstrates marked down-regulation after frataxin deletion in the heart. This was due, in part, to a pronounced increase in Keap1. To assess if this can be therapeutically targeted, cells were incubated with N-acetylcysteine (NAC), or buthionine sulfoximine (BSO), which increases or decreases glutathione (GSH), respectively, or the NRF2-inducer, sulforaphane (SFN). While SFN significantly (p < 0.05) induced NRF2, KEAP1 and BACH1, NAC attenuated SFN-induced NRF2, KEAP1 and BACH1. The down-regulation of KEAP1 by NAC was of interest, as Keap1 is markedly increased in the MCK conditional frataxin knockout (MCK KO) mouse model and this could lead to the decreased Nrf2 levels. Considering this, MCK KO mice were treated with i.p. NAC (500- or 1500-mg/kg, 5 days/week for 5-weeks) and demonstrated slightly less (p > 0.05) body weight loss versus the vehicle-treated KO. However, NAC did not rescue the cardiomyopathy. To additionally examine the dys-regulation of Nrf2 upon frataxin deletion, studies assessed the role of microRNA (miRNA) in this process. In MCK KO mice, miR-144 was up-regulated, which down-regulates Nrf2. Furthermore, miRNA screening in MCK KO mice demonstrated 23 miRNAs from 756 screened were significantly (p < 0.05) altered in KOs versus WT littermates. Of these, miR-21*, miR-34c*, and miR-200c, demonstrated marked alterations, with functional clustering analysis showing they regulate genes linked to cardiac hypertrophy, cardiomyopathy, and oxidative stress, respectively.
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MESH Headings
- Acetylcysteine/pharmacology
- Animals
- Basic-Leucine Zipper Transcription Factors/metabolism
- Cardiomyopathy, Dilated/drug therapy
- Cardiomyopathy, Dilated/etiology
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cell Line, Tumor
- Disease Models, Animal
- Friedreich Ataxia/complications
- Friedreich Ataxia/genetics
- Gene Expression Regulation
- Humans
- Iron-Binding Proteins/genetics
- Iron-Binding Proteins/metabolism
- Isothiocyanates/pharmacology
- Kelch-Like ECH-Associated Protein 1/metabolism
- Mice, Knockout
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- NF-E2-Related Factor 2/genetics
- NF-E2-Related Factor 2/metabolism
- Sulfoxides/pharmacology
- Frataxin
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Affiliation(s)
- S Chiang
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Medical Foundation Building (K25), University of Sydney, Sydney, New South Wales, 2006 Australia
| | - M L H Huang
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Medical Foundation Building (K25), University of Sydney, Sydney, New South Wales, 2006 Australia
| | - D R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Medical Foundation Building (K25), University of Sydney, Sydney, New South Wales, 2006 Australia; Centre for Cancer Cell Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, 4111, Queensland, Australia.
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6
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Angeloni C, Gatti M, Prata C, Hrelia S, Maraldi T. Role of Mesenchymal Stem Cells in Counteracting Oxidative Stress-Related Neurodegeneration. Int J Mol Sci 2020; 21:ijms21093299. [PMID: 32392722 PMCID: PMC7246730 DOI: 10.3390/ijms21093299] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/30/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023] Open
Abstract
Neurodegenerative diseases include a variety of pathologies such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and so forth, which share many common characteristics such as oxidative stress, glycation, abnormal protein deposition, inflammation, and progressive neuronal loss. The last century has witnessed significant research to identify mechanisms and risk factors contributing to the complex etiopathogenesis of neurodegenerative diseases, such as genetic, vascular/metabolic, and lifestyle-related factors, which often co-occur and interact with each other. Apart from several environmental or genetic factors, in recent years, much evidence hints that impairment in redox homeostasis is a common mechanism in different neurological diseases. However, from a pharmacological perspective, oxidative stress is a difficult target, and antioxidants, the only strategy used so far, have been ineffective or even provoked side effects. In this review, we report an analysis of the recent literature on the role of oxidative stress in Alzheimer’s and Parkinson’s diseases as well as in amyotrophic lateral sclerosis, retinal ganglion cells, and ataxia. Moreover, the contribution of stem cells has been widely explored, looking at their potential in neuronal differentiation and reporting findings on their application in fighting oxidative stress in different neurodegenerative diseases. In particular, the exposure to mesenchymal stem cells or their secretome can be considered as a promising therapeutic strategy to enhance antioxidant capacity and neurotrophin expression while inhibiting pro-inflammatory cytokine secretion, which are common aspects of neurodegenerative pathologies. Further studies are needed to identify a tailored approach for each neurodegenerative disease in order to design more effective stem cell therapeutic strategies to prevent a broad range of neurodegenerative disorders.
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Affiliation(s)
- Cristina Angeloni
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032 Camerino, Italy;
| | - Martina Gatti
- Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia, Via del Pozzo 71, 41124 Modena, Italy; (M.G.); (T.M.)
| | - Cecilia Prata
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum—University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
- Correspondence:
| | - Silvana Hrelia
- Department for Life Quality Studies, Alma Mater Studiorum—University of Bologna, Corso d’Augusto 237, 47921 Rimini, Italy;
| | - Tullia Maraldi
- Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia, Via del Pozzo 71, 41124 Modena, Italy; (M.G.); (T.M.)
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7
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Muñoz-Lasso DC, Mollá B, Calap-Quintana P, García-Giménez JL, Pallardo FV, Palau F, Gonzalez-Cabo P. Cofilin dysregulation alters actin turnover in frataxin-deficient neurons. Sci Rep 2020; 10:5207. [PMID: 32251310 PMCID: PMC7090085 DOI: 10.1038/s41598-020-62050-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 03/04/2020] [Indexed: 01/04/2023] Open
Abstract
Abnormalities in actin cytoskeleton have been linked to Friedreich's ataxia (FRDA), an inherited peripheral neuropathy characterised by an early loss of neurons in dorsal root ganglia (DRG) among other clinical symptoms. Despite all efforts to date, we still do not fully understand the molecular events that contribute to the lack of sensory neurons in FRDA. We studied the adult neuronal growth cone (GC) at the cellular and molecular level to decipher the connection between frataxin and actin cytoskeleton in DRG neurons of the well-characterised YG8R Friedreich's ataxia mouse model. Immunofluorescence studies in primary cultures of DRG from YG8R mice showed neurons with fewer and smaller GCs than controls, associated with an inhibition of neurite growth. In frataxin-deficient neurons, we also observed an increase in the filamentous (F)-actin/monomeric (G)-actin ratio (F/G-actin ratio) in axons and GCs linked to dysregulation of two crucial modulators of filamentous actin turnover, cofilin-1 and the actin-related protein (ARP) 2/3 complex. We show how the activation of cofilin is due to the increase in chronophin (CIN), a cofilin-activating phosphatase. Thus cofilin emerges, for the first time, as a link between frataxin deficiency and actin cytoskeleton alterations.
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Affiliation(s)
- Diana C Muñoz-Lasso
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain
- Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain
| | - Belén Mollá
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Instituto de Biomedicina de Valencia (IBV), CSIC, Valencia, 46010, Spain
| | - Pablo Calap-Quintana
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain
- Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain
| | - José Luis García-Giménez
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain
- Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain
| | - Federico V Pallardo
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain
- Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain
| | - Francesc Palau
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
- Institut de Recerca Sant Joan de Déu and Department of Genetic & Molecular Medicine and IPER, Hospital Sant Joan de Déu, Barcelona, 08950, Spain
- Hospital Clínic and Division of Pediatrics, University of Barcelona School of Medicine and Health Sciences, Barcelona, Spain
| | - Pilar Gonzalez-Cabo
- CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain.
- Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain.
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8
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Bolotta A, Pini A, Abruzzo PM, Ghezzo A, Modesti A, Gamberi T, Ferreri C, Bugamelli F, Fortuna F, Vertuani S, Manfredini S, Zucchini C, Marini M. Effects of tocotrienol supplementation in Friedreich's ataxia: A model of oxidative stress pathology. Exp Biol Med (Maywood) 2020; 245:201-212. [PMID: 31795754 PMCID: PMC7045332 DOI: 10.1177/1535370219890873] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 11/04/2019] [Indexed: 01/08/2023] Open
Abstract
Friedreich’s ataxia is an autosomal recessive disorder characterized by impaired mitochondrial function, resulting in oxidative stress. In this study, we aimed at evaluating whether tocotrienol, a phytonutrient that diffuses easily in tissues with saturated fatty layers, could complement the current treatment with idebenone, a quinone analogue with antioxidant properties. Five young Friedreich’s ataxia patients received a low-dose tocotrienol supplementation (5 mg/kg/day), while not discontinuing idebenone treatment. Several oxidative stress markers and biological parameters related to oxidative stress were evaluated at the time of initiation of treatment and 2 and 12 months post-treatment. Some oxidative stress-related parameters and some inflammation indices were altered in Friedreich’s ataxia patients taking idebenone alone and tended to be normal values following tocotrienol supplementation; likewise, a cardiac magnetic resonance study showed some improvement following one-year tocotrienol treatment. The pathway by which tocotrienol affects the Nrf2 modulation of hepcidin gene expression, a peptide involved in iron handling and in inflammatory responses, is viewed in the light of the disruption of the iron intracellular distribution and of the Nrf2 anergy characterizing Friedreich’s ataxia. This research provides a suitable model to analyze the efficacy of therapeutic strategies able to counteract the excess free radicals in Friedreich’s ataxia, and paves the way to long-term clinical studies.
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Affiliation(s)
- Alessandra Bolotta
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy
- IRCCS Fondazione Don Carlo Gnocchi, Milan 20148, Italy
| | - Antonella Pini
- Child Neurology and Psychiatry Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna 40139, Italy
| | - Provvidenza M Abruzzo
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy
- IRCCS Fondazione Don Carlo Gnocchi, Milan 20148, Italy
| | - Alessandro Ghezzo
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy
| | - Alessandra Modesti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Firenze 50134, Italy
| | - Tania Gamberi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, Firenze 50134, Italy
| | | | - Francesca Bugamelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy
| | - Filippo Fortuna
- Neurochemistry Laboratory, Azienda Ospedaliera Ospedali Riuniti Marche Nord, Pesaro 61121, Italy
| | - Silvia Vertuani
- Department of Pharmaceutical Sciences, University of Ferrara, Ferrara 44100, Italy
| | - Stefano Manfredini
- Department of Pharmaceutical Sciences, University of Ferrara, Ferrara 44100, Italy
| | - Cinzia Zucchini
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy
| | - Marina Marini
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna 40126, Italy
- IRCCS Fondazione Don Carlo Gnocchi, Milan 20148, Italy
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9
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Bon C, Luffarelli R, Russo R, Fortuni S, Pierattini B, Santulli C, Fimiani C, Persichetti F, Cotella D, Mallamaci A, Santoro C, Carninci P, Espinoza S, Testi R, Zucchelli S, Condò I, Gustincich S. SINEUP non-coding RNAs rescue defective frataxin expression and activity in a cellular model of Friedreich's Ataxia. Nucleic Acids Res 2019; 47:10728-10743. [PMID: 31584077 PMCID: PMC6847766 DOI: 10.1093/nar/gkz798] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 08/08/2019] [Accepted: 09/28/2019] [Indexed: 12/16/2022] Open
Abstract
Friedreich's ataxia (FRDA) is an untreatable disorder with neuro- and cardio-degenerative progression. This monogenic disease is caused by the hyper-expansion of naturally occurring GAA repeats in the first intron of the FXN gene, encoding for frataxin, a protein implicated in the biogenesis of iron-sulfur clusters. As the genetic defect interferes with FXN transcription, FRDA patients express a normal frataxin protein but at insufficient levels. Thus, current therapeutic strategies are mostly aimed to restore physiological FXN expression. We have previously described SINEUPs, natural and synthetic antisense long non-coding RNAs, which promote translation of partially overlapping mRNAs through the activity of an embedded SINEB2 domain. Here, by in vitro screening, we have identified a number of SINEUPs targeting human FXN mRNA and capable to up-regulate frataxin protein to physiological amounts acting at the post-transcriptional level. Furthermore, FXN-specific SINEUPs promote the recovery of disease-associated mitochondrial aconitase defects in FRDA-derived cells. In summary, we provide evidence that SINEUPs may be the first gene-specific therapeutic approach to activate FXN translation in FRDA and, more broadly, a novel scalable platform to develop new RNA-based therapies for haploinsufficient diseases.
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Affiliation(s)
- Carlotta Bon
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
| | - Riccardo Luffarelli
- Department of Biomedicine and Prevention, Laboratory of Signal Transduction, University of Rome Tor Vergata, Rome, Italy
| | - Roberta Russo
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
| | - Silvia Fortuni
- Department of Biomedicine and Prevention, Laboratory of Signal Transduction, University of Rome Tor Vergata, Rome, Italy
| | - Bianca Pierattini
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
| | - Chiara Santulli
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
| | - Cristina Fimiani
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
| | - Francesca Persichetti
- Department of Health Sciences and Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Diego Cotella
- Department of Health Sciences and Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Antonello Mallamaci
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
| | - Claudio Santoro
- Department of Health Sciences and Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Piero Carninci
- RIKEN Center for Life Science Technologies, Division of Genomic Technologies, Yokohama, Kanagawa, Japan
| | - Stefano Espinoza
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
| | - Roberto Testi
- Department of Biomedicine and Prevention, Laboratory of Signal Transduction, University of Rome Tor Vergata, Rome, Italy
| | - Silvia Zucchelli
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
- Department of Health Sciences and Interdisciplinary Research Center of Autoimmune Diseases (IRCAD), University of Piemonte Orientale (UPO), Novara, Italy
| | - Ivano Condò
- Department of Biomedicine and Prevention, Laboratory of Signal Transduction, University of Rome Tor Vergata, Rome, Italy
| | - Stefano Gustincich
- Central RNA Laboratory, Istituto Italiano di Tecnologia (IIT), Genova, Italy
- Area of Neuroscience, International School for Advanced Studies (SISSA), Italy
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10
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Georges P, Boza-Moran MG, Gide J, Pêche GA, Forêt B, Bayot A, Rustin P, Peschanski M, Martinat C, Aubry L. Induced pluripotent stem cells-derived neurons from patients with Friedreich ataxia exhibit differential sensitivity to resveratrol and nicotinamide. Sci Rep 2019; 9:14568. [PMID: 31601825 PMCID: PMC6787055 DOI: 10.1038/s41598-019-49870-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/30/2019] [Indexed: 12/20/2022] Open
Abstract
Translation of pharmacological results from in vitro cell testing to clinical trials is challenging. One of the causes that may underlie these discrepant results is the lack of the phenotypic or species-specific relevance of the tested cells; today, this lack of relevance may be reduced by relying on cells differentiated from human pluripotent stem cells. To analyse the benefits provided by this approach, we chose to focus on Friedreich ataxia, a neurodegenerative condition for which the recent clinical testing of two compounds was not successful. These compounds, namely, resveratrol and nicotinamide, were selected because they had been shown to stimulate the expression of frataxin in fibroblasts and lymphoblastoid cells. Our results indicated that these compounds failed to do so in iPSC-derived neurons generated from two patients with Friedreich ataxia. By comparing the effects of both molecules on different cell types that may be considered to be non-relevant for the disease, such as fibroblasts, or more relevant to the disease, such as neurons differentiated from iPSCs, a differential response was observed; this response suggests the importance of developing more predictive in vitro systems for drug discovery. Our results demonstrate the value of utilizing human iPSCs early in drug discovery to improve translational predictability.
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Affiliation(s)
| | - Maria-Gabriela Boza-Moran
- INSERM UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
- UEVE, Paris-Saclay UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
| | | | - Georges Arielle Pêche
- INSERM UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
- UEVE, Paris-Saclay UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
| | | | - Aurélien Bayot
- CNRS UMR 3691, Institut Pasteur, Mitochondrial Biology Group, Paris, France
| | - Pierre Rustin
- Hôpital Robert Debré, INSERM UMR, 1141, Paris, France
| | - Marc Peschanski
- INSERM UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
- UEVE, Paris-Saclay UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
| | - Cécile Martinat
- INSERM UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
- UEVE, Paris-Saclay UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France
| | - Laetitia Aubry
- INSERM UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France.
- UEVE, Paris-Saclay UMR 861, I-STEM, AFM, 91100, Corbeil-Essonnes, France.
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11
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Synofzik M, Puccio H, Mochel F, Schöls L. Autosomal Recessive Cerebellar Ataxias: Paving the Way toward Targeted Molecular Therapies. Neuron 2019; 101:560-583. [PMID: 30790538 DOI: 10.1016/j.neuron.2019.01.049] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/20/2018] [Accepted: 01/23/2019] [Indexed: 12/22/2022]
Abstract
Autosomal-recessive cerebellar ataxias (ARCAs) comprise a heterogeneous group of rare degenerative and metabolic genetic diseases that share the hallmark of progressive damage of the cerebellum and its associated tracts. This Review focuses on recent translational research in ARCAs and illustrates the steps from genetic characterization to preclinical and clinical trials. The emerging common pathways underlying ARCAs include three main clusters: mitochondrial dysfunction, impaired DNA repair, and complex lipid homeostasis. Novel ARCA treatments might target common hubs in pathogenesis by modulation of gene expression, stem cell transplantation, viral gene transfer, or interventions in faulty pathways. All these translational steps are addressed in current ARCA research, leading to the expectation that novel treatments for ARCAs will be reached in the next decade.
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Affiliation(s)
- Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Hélène Puccio
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; INSERM, U1258, 67404 Illkirch, France; CNRS, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Fanny Mochel
- Sorbonne Université, UPMC-Paris 6, UMR S 1127 and Inserm U 1127, and CNRS UMR 7225, and Institut du Cerveau et de la Moelle épinière, 75013 Paris, France; Department of Genetics and Reference Centre for Adult Neurometabolic Diseases, AP-HP, La Pitié-Salpêtriere University Hospital, Paris, France
| | - Ludger Schöls
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany.
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12
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Sbodio JI, Snyder SH, Paul BD. Redox Mechanisms in Neurodegeneration: From Disease Outcomes to Therapeutic Opportunities. Antioxid Redox Signal 2019; 30:1450-1499. [PMID: 29634350 PMCID: PMC6393771 DOI: 10.1089/ars.2017.7321] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 03/16/2018] [Accepted: 03/18/2018] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Once considered to be mere by-products of metabolism, reactive oxygen, nitrogen and sulfur species are now recognized to play important roles in diverse cellular processes such as response to pathogens and regulation of cellular differentiation. It is becoming increasingly evident that redox imbalance can impact several signaling pathways. For instance, disturbances of redox regulation in the brain mediate neurodegeneration and alter normal cytoprotective responses to stress. Very often small disturbances in redox signaling processes, which are reversible, precede damage in neurodegeneration. Recent Advances: The identification of redox-regulated processes, such as regulation of biochemical pathways involved in the maintenance of redox homeostasis in the brain has provided deeper insights into mechanisms of neuroprotection and neurodegeneration. Recent studies have also identified several post-translational modifications involving reactive cysteine residues, such as nitrosylation and sulfhydration, which fine-tune redox regulation. Thus, the study of mechanisms via which cell death occurs in several neurodegenerative disorders, reveal several similarities and dissimilarities. Here, we review redox regulated events that are disrupted in neurodegenerative disorders and whose modulation affords therapeutic opportunities. CRITICAL ISSUES Although accumulating evidence suggests that redox imbalance plays a significant role in progression of several neurodegenerative diseases, precise understanding of redox regulated events is lacking. Probes and methodologies that can precisely detect and quantify in vivo levels of reactive oxygen, nitrogen and sulfur species are not available. FUTURE DIRECTIONS Due to the importance of redox control in physiologic processes, organisms have evolved multiple pathways to counteract redox imbalance and maintain homeostasis. Cells and tissues address stress by harnessing an array of both endogenous and exogenous redox active substances. Targeting these pathways can help mitigate symptoms associated with neurodegeneration and may provide avenues for novel therapeutics. Antioxid. Redox Signal. 30, 1450-1499.
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Affiliation(s)
- Juan I. Sbodio
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Solomon H. Snyder
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bindu D. Paul
- The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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13
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Alsina D, Purroy R, Ros J, Tamarit J. Iron in Friedreich Ataxia: A Central Role in the Pathophysiology or an Epiphenomenon? Pharmaceuticals (Basel) 2018; 11:E89. [PMID: 30235822 PMCID: PMC6161073 DOI: 10.3390/ph11030089] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 12/16/2022] Open
Abstract
Friedreich ataxia is a neurodegenerative disease with an autosomal recessive inheritance. In most patients, the disease is caused by the presence of trinucleotide GAA expansions in the first intron of the frataxin gene. These expansions cause the decreased expression of this mitochondrial protein. Many evidences indicate that frataxin deficiency causes the deregulation of cellular iron homeostasis. In this review, we will discuss several hypotheses proposed for frataxin function, their caveats, and how they could provide an explanation for the deregulation of iron homeostasis found in frataxin-deficient cells. We will also focus on the potential mechanisms causing cellular dysfunction in Friedreich Ataxia and on the potential use of the iron chelator deferiprone as a therapeutic agent for this disease.
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Affiliation(s)
- David Alsina
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
| | - Rosa Purroy
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
| | - Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
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14
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Liu P, Lin H, Xu Y, Zhou F, Wang J, Liu J, Zhu X, Guo X, Tang Y, Yao P. Frataxin-Mediated PINK1-Parkin-Dependent Mitophagy in Hepatic Steatosis: The Protective Effects of Quercetin. Mol Nutr Food Res 2018; 62:e1800164. [PMID: 29935106 DOI: 10.1002/mnfr.201800164] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 05/20/2018] [Indexed: 12/18/2022]
Abstract
SCOPE Naturally occurring quercetin has been found to induce mitophagy and prevent nonalcoholic fatty liver disease (NAFLD). However, it still remains elusive whether frataxin upregulation by quercetin contributes to the beneficial effect through mitophagy or not. METHODS AND RESULTS Adult male C57BL/J mice were fed a high-fat diet (HFD, 60% of energy from fat) with quercetin (100 mg kg-1 body weight) or not for 10 weeks. Quercetin alleviated HFD-induced histopathological changes, disorders of lipid metabolism, and mitochondrial damage. Moreover, quercetin blocked mitophagy suppression by HFD based on the increased LC3II, PTEN-induced putative kinase 1 (PINK1) and Beclin1 expressions, as well as decreased p62 levels. Quercetin also improved the Parkin translocation to mitochondria confirmed by immunofluorescence. Specifically, frataxin was lowered in the liver of HFD-fed mice or HepG2 cell incubated with oleate/palmitate but restored by quercetin, and quercetin's regulation of frataxin may depend on p53. Furthermore, lentivirus-mediated stable knockdown of frataxin in HepG2 inhibited PINK1-Parkin-associated mitophagy and resulted in lipid accumulation. Frataxin was further decreased by free fatty acids in knockdown cells concomitantly with depressed PINK1-Parkin-associated mitophagy, which was partially normalized by quercetin. CONCLUSION Quercetin alleviated hepatic steatosis by enhancing frataxin-mediated PINK1/Parkin-dependent mitophagy, highlighting a promising preventive strategy and mechanism for NAFLD by quercetin.
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Affiliation(s)
- Peiyi Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Hongkun Lin
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Yanyan Xu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Feng Zhou
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Jing Wang
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Jingjing Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Xinhong Zhu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Xiaoping Guo
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Yuhan Tang
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Ping Yao
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
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15
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Alsina D, Ros J, Tamarit J. Nitric oxide prevents Aft1 activation and metabolic remodeling in frataxin-deficient yeast. Redox Biol 2018; 14:131-141. [PMID: 28918000 PMCID: PMC5602528 DOI: 10.1016/j.redox.2017.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/25/2017] [Accepted: 09/02/2017] [Indexed: 11/30/2022] Open
Abstract
Yeast frataxin homolog (Yfh1) is the orthologue of human frataxin, a mitochondrial protein whose deficiency causes Friedreich Ataxia. Yfh1 deficiency activates Aft1, a transcription factor governing iron homeostasis in yeast cells. Although the mechanisms causing this activation are not completely understood, it is assumed that it may be caused by iron-sulfur deficiency. However, several evidences indicate that activation of Aft1 occurs in the absence of iron-sulfur deficiency. Besides, Yfh1 deficiency also leads to metabolic remodeling (mainly consisting in a shift from respiratory to fermentative metabolism) and to induction of Yhb1, a nitric oxide (NO) detoxifying enzyme. In this work, we have used conditional Yfh1 mutant yeast strains to investigate the relationship between NO, Aft1 activation and metabolic remodeling. We have observed that NO prevents Aft1 activation caused by Yfh1 deficiency. This phenomenon is not observed when Aft1 is activated by iron scarcity or impaired iron-sulfur biogenesis. In addition, analyzing key metabolic proteins by a targeted proteomics approach, we have observed that NO prevents the metabolic remodeling caused by Yfh1 deficiency. We conclude that Aft1 activation in Yfh1-deficient yeasts is not caused by iron-sulfur deficiency or iron scarcity. Our hypothesis is that Yfh1 deficiency leads to the presence of anomalous iron species that can compromise iron bioavailability and activate a signaling cascade that results in Aft1 activation and metabolic remodeling.
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Affiliation(s)
- David Alsina
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Lleida, Spain
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Lleida, Spain
| | - Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, Lleida, Spain.
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16
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Nonneurological Involvement in Late-Onset Friedreich Ataxia (LOFA): Exploring the Phenotypes. THE CEREBELLUM 2017; 16:253-256. [PMID: 26754264 DOI: 10.1007/s12311-015-0755-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Friedreich's ataxia (FDRA) is the most common inherited ataxia worldwide, caused by homozygous GAA expansions in the FXN gene. Patients usually have early onset ataxia, areflexia, Babinski sign, scoliosis and pes cavus, but at least 25 % of cases have atypical phenotypes. Disease begins after the age of 25 in occasional patients (late-onset Friedreich ataxia (LOFA)). Little is known about the frequency and clinical profile of LOFA patients. One hundred six patients with molecular confirmation of FDRA and followed in three Brazilian outpatient centers were enrolled. General demographics, GAA expansion size, age at onset, cardiac, endocrine, and skeletal manifestations were evaluated and compared between LOFA and classic FDRA (cFDRA) groups. We used Mann-Whitney and Fisher tests to compare means and proportions between groups; p values <0.05 were considered significant. LOFA accounted for 17 % (18/106) and cFDRA for 83 % (88/106) of the patients. There were 13 and 48 women in each group, respectively. LOFA patients were significantly older and had smaller GAA expansions. Clinically, LOFA group had a tendency toward lower frequency of diabetes/impaired glucose tolerance (5.8 vs. 17 %, p = 0.29) and cardiomyopathy (16.6 vs. 28.4 %, p = 0.38). Skeletal abnormalities were significantly less frequent in LOFA (scoliosis 22 vs. 61 %, p = 0.003, and pes cavus 22 vs.75 %, p < 0.001) as were spasticity and sustained reflexes, found in 22 % of LOFA patients but in none of the cFDRA patients (p = 0.001). LOFA accounts for 17 % of Brazilian FDRA patients evaluated herein. Clinically, orthopedic features and spasticity with retained reflexes are helpful tips to differentiate LOFA from cFDRA patients.
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17
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Han THL, Camadro JM, Santos R, Lesuisse E, El Hage Chahine JM, Ha-Duong NT. Mechanisms of iron and copper-frataxin interactions. Metallomics 2017; 9:1073-1085. [PMID: 28573291 DOI: 10.1039/c7mt00031f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Frataxin is a mitochondrial protein whose deficiency is the cause of Friedreich's ataxia, a hereditary neurodegenerative disease. This protein plays a role in iron-sulfur cluster biosynthesis, protection against oxidative stress and iron metabolism. In an attempt to provide a better understanding of the role played by metals in its metabolic functions, the mechanisms of mitochondrial metal binding to frataxin in vitro have been investigated. A purified recombinant yeast frataxin homolog Yfh1 binds two Cu(ii) ions with a Kd1(CuII) of 1.3 × 10-7 M and a Kd2(CuII) of 3.1 × 10-4 M and a single Cu(i) ion with a higher affinity than for Cu(ii) (Kd(CuI) = 3.2 × 10-8 M). Mn(ii) forms two complexes with Yfh1 (Kd1(MnII) = 4.0 × 10-8 M; Kd2(MnII) = 4.0 × 10-7 M). Cu and Mn bind Yfh1 with higher affinities than Fe(ii). It is established for the first time that the mechanisms of the interaction of iron and copper with frataxin are comparable and involve three kinetic steps. The first step occurs in the 50-500 ms range and corresponds to a first metal uptake. This is followed by two other kinetic processes that are related to a second metal uptake and/or to a change in the conformation leading to thermodynamic equilibrium. Frataxin deficient Δyfh1 yeast cells exhibited a marked growth defect in the presence of exogenous Cu or Mn. Mitochondria from Δyfh1 strains also accumulated higher amounts of copper, suggesting a functional role of frataxin in vivo in copper homeostasis.
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Affiliation(s)
- T H L Han
- Université Paris Diderot, Sorbonne Paris Cité, "Interfaces, Traitements, Organisation et Dynamique des Systèmes", CNRS-UMR 7086, 15 rue Jean Antoine de Baïf, 75205 Paris Cedex 13, France.
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18
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Kemp K, Dey R, Cook A, Scolding N, Wilkins A. Mesenchymal Stem Cell-Derived Factors Restore Function to Human Frataxin-Deficient Cells. CEREBELLUM (LONDON, ENGLAND) 2017; 16:840-851. [PMID: 28456899 PMCID: PMC5498643 DOI: 10.1007/s12311-017-0860-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Friedreich's ataxia is an inherited neurological disorder characterised by mitochondrial dysfunction and increased susceptibility to oxidative stress. At present, no therapy has been shown to reduce disease progression. Strategies being trialled to treat Friedreich's ataxia include drugs that improve mitochondrial function and reduce oxidative injury. In addition, stem cells have been investigated as a potential therapeutic approach. We have used siRNA-induced knockdown of frataxin in SH-SY5Y cells as an in vitro cellular model for Friedreich's ataxia. Knockdown of frataxin protein expression to levels detected in patients with the disorder was achieved, leading to decreased cellular viability, increased susceptibility to hydrogen peroxide-induced oxidative stress, dysregulation of key anti-oxidant molecules and deficiencies in both cell proliferation and differentiation. Bone marrow stem cells are being investigated extensively as potential treatments for a wide range of neurological disorders, including Friedreich's ataxia. The potential neuroprotective effects of bone marrow-derived mesenchymal stem cells were therefore studied using our frataxin-deficient cell model. Soluble factors secreted by mesenchymal stem cells protected against cellular changes induced by frataxin deficiency, leading to restoration in frataxin levels and anti-oxidant defences, improved survival against oxidative stress and stimulated both cell proliferation and differentiation down the Schwann cell lineage. The demonstration that mesenchymal stem cell-derived factors can restore cellular homeostasis and function to frataxin-deficient cells further suggests that they may have potential therapeutic benefits for patients with Friedreich's ataxia.
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Affiliation(s)
- Kevin Kemp
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK.
| | - Rimi Dey
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Amelia Cook
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Neil Scolding
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Alastair Wilkins
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
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19
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Chen K, Ho TSY, Lin G, Tan KL, Rasband MN, Bellen HJ. Loss of Frataxin activates the iron/sphingolipid/PDK1/Mef2 pathway in mammals. eLife 2016; 5:e20732. [PMID: 27901468 PMCID: PMC5130293 DOI: 10.7554/elife.20732] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 11/17/2016] [Indexed: 01/05/2023] Open
Abstract
Friedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disease caused by mutations in Frataxin (FXN). Loss of FXN causes impaired mitochondrial function and iron homeostasis. An elevated production of reactive oxygen species (ROS) was previously proposed to contribute to the pathogenesis of FRDA. We recently showed that loss of frataxin homolog (fh), a Drosophila homolog of FXN, causes a ROS independent neurodegeneration in flies (Chen et al., 2016). In fh mutants, iron accumulation in the nervous system enhances the synthesis of sphingolipids, which in turn activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2) to trigger neurodegeneration of adult photoreceptors. Here, we show that loss of Fxn in the nervous system in mice also activates an iron/sphingolipid/PDK1/Mef2 pathway, indicating that the mechanism is evolutionarily conserved. Furthermore, sphingolipid levels and PDK1 activity are also increased in hearts of FRDA patients, suggesting that a similar pathway is affected in FRDA.
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Affiliation(s)
- Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kai Li Tan
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Matthew N Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Houston, United States
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20
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DeBrosse C, Nanga RPR, Wilson N, D'Aquilla K, Elliott M, Hariharan H, Yan F, Wade K, Nguyen S, Worsley D, Parris-Skeete C, McCormick E, Xiao R, Cunningham ZZ, Fishbein L, Nathanson KL, Lynch DR, Stallings VA, Yudkoff M, Falk MJ, Reddy R, McCormack SE. Muscle oxidative phosphorylation quantitation using creatine chemical exchange saturation transfer (CrCEST) MRI in mitochondrial disorders. JCI Insight 2016; 1:e88207. [PMID: 27812541 DOI: 10.1172/jci.insight.88207] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Systemic mitochondrial energy deficiency is implicated in the pathophysiology of many age-related human diseases. Currently available tools to estimate mitochondrial oxidative phosphorylation (OXPHOS) capacity in skeletal muscle in vivo lack high anatomic resolution. Muscle groups vary with respect to their contractile and metabolic properties. Therefore, muscle group-specific estimates of OXPHOS would be advantageous. To address this need, a noninvasive creatine chemical exchange saturation transfer (CrCEST) MRI technique has recently been developed, which provides a measure of free creatine. After exercise, skeletal muscle can be imaged with CrCEST in order to make muscle group-specific measurements of OXPHOS capacity, reflected in the recovery rate (τCr) of free Cr. In this study, we found that individuals with genetic mitochondrial diseases had significantly (P = 0.026) prolonged postexercise τCr in the medial gastrocnemius muscle, suggestive of less OXPHOS capacity. Additionally, we observed that lower resting CrCEST was associated with prolonged τPCr, with a Pearson's correlation coefficient of -0.42 (P = 0.046), consistent with previous hypotheses predicting that resting creatine levels may correlate with 31P magnetic resonance spectroscopy-based estimates of OXPHOS capacity. We conclude that CrCEST can noninvasively detect changes in muscle creatine content and OXPHOS capacity, with high anatomic resolution, in individuals with mitochondrial disorders.
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Affiliation(s)
- Catherine DeBrosse
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravi Prakash Reddy Nanga
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neil Wilson
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kevin D'Aquilla
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark Elliott
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hari Hariharan
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felicia Yan
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | - Kristin Wade
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | - Sara Nguyen
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | - Diana Worsley
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia
| | | | - Elizabeth McCormick
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Rui Xiao
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Lauren Fishbein
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Katherine L Nathanson
- Division of Translational Medicine and Human Genetics, Department of Medicine, Perelman School of Medicine, University of Pennsylvania.,Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania
| | - David R Lynch
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Virginia A Stallings
- Division of Gastroenterology, Hepatology, and Nutrition, The Children's Hospital of Philadelphia.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marc Yudkoff
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marni J Falk
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shana E McCormack
- Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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21
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Tamarit J, Obis È, Ros J. Oxidative stress and altered lipid metabolism in Friedreich ataxia. Free Radic Biol Med 2016; 100:138-146. [PMID: 27296838 DOI: 10.1016/j.freeradbiomed.2016.06.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 12/31/2022]
Abstract
Friedreich ataxia is a genetic disease caused by the deficiency of frataxin, a mitochondrial protein. Frataxin deficiency impacts in the cell physiology at several levels. One of them is oxidative stress with consequences in terms of protein dysfunctions and metabolic alterations. Among others, alterations in lipid metabolism have been observed in several models of the disease. In this review we summarize the current knowledge of the molecular basis of the disease, the relevance of oxidative stress and the therapeutic strategies based on reduction of mitochondrial reactive oxygen species production. Finally, we will focus the interest in alterations of lipid metabolism as a consequence of mitochondrial dysfunction and describe the therapeutic approaches based on targeting lipid metabolism.
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Affiliation(s)
- Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Èlia Obis
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain.
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22
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Piermarini E, Cartelli D, Pastore A, Tozzi G, Compagnucci C, Giorda E, D'Amico J, Petrini S, Bertini E, Cappelletti G, Piemonte F. Frataxin silencing alters microtubule stability in motor neurons: implications for Friedreich's ataxia. Hum Mol Genet 2016; 25:4288-4301. [PMID: 27516386 DOI: 10.1093/hmg/ddw260] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 07/04/2016] [Accepted: 07/19/2016] [Indexed: 12/23/2022] Open
Abstract
To elucidate the pathogenesis of axonopathy in Friedreich's Ataxia (FRDA), a neurodegenerative disease characterized by axonal retraction, we analyzed the microtubule (MT) dynamics in an in vitro frataxin-silenced neuronal model (shFxn). A typical feature of MTs is their "dynamic instability", in which they undergo phases of growth (polymerization) and shrinkage (depolymerization). MTs play a fundamental role in the physiology of neurons and every perturbation of their dynamicity is highly detrimental for neuronal functions. The aim of this study is to determine whether MTs are S-glutathionylated in shFxn and if the glutathionylation triggers MT dysfunction. We hypothesize that oxidative stress, determined by high GSSG levels, induces axonal retraction by interfering with MT dynamics. We propose a mechanism of the axonopathy in FRDA where GSSG overload and MT de-polymerization are strictly interconnected. Indeed, using a frataxin-silenced neuronal model we show a significant reduction of neurites extension, a shift of tubulin toward the unpolymerized fraction and a consistent increase of glutathione bound to the cytoskeleton. The live cell imaging approach further reveals a significant decrease in MT growth lifetime due to frataxin silencing, which is consistent with the MT destabilization. The in vitro antioxidant treatments trigger the axonal re-growth and the increase in stable MTs in shFxn, thus contributing to identify new neuronal targets of oxidation in this disease and providing a novel approach for antioxidant therapies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Graziella Cappelletti
- Department of Biosciences
- Center of Excellence on Neurodegenerative Diseases, University of Milan, Via Celoria 26, Milan, Italy
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23
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Chen K, Lin G, Haelterman NA, Ho TSY, Li T, Li Z, Duraine L, Graham BH, Jaiswal M, Yamamoto S, Rasband MN, Bellen HJ. Loss of Frataxin induces iron toxicity, sphingolipid synthesis, and Pdk1/Mef2 activation, leading to neurodegeneration. eLife 2016; 5:e16043. [PMID: 27343351 PMCID: PMC4956409 DOI: 10.7554/elife.16043] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
Mutations in Frataxin (FXN) cause Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder. Previous studies have proposed that loss of FXN causes mitochondrial dysfunction, which triggers elevated reactive oxygen species (ROS) and leads to the demise of neurons. Here we describe a ROS independent mechanism that contributes to neurodegeneration in fly FXN mutants. We show that loss of frataxin homolog (fh) in Drosophila leads to iron toxicity, which in turn induces sphingolipid synthesis and ectopically activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2). Dampening iron toxicity, inhibiting sphingolipid synthesis by Myriocin, or reducing Pdk1 or Mef2 levels, all effectively suppress neurodegeneration in fh mutants. Moreover, increasing dihydrosphingosine activates Mef2 activity through PDK1 in mammalian neuronal cell line suggesting that the mechanisms are evolutionarily conserved. Our results indicate that an iron/sphingolipid/Pdk1/Mef2 pathway may play a role in FRDA.
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Affiliation(s)
- Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
| | - Matthew N Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
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24
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Poburski D, Boerner JB, Koenig M, Ristow M, Thierbach R. Time-resolved functional analysis of acute impairment of frataxin expression in an inducible cell model of Friedreich ataxia. Biol Open 2016; 5:654-61. [PMID: 27106929 PMCID: PMC4874353 DOI: 10.1242/bio.017004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Friedreich ataxia is a neurodegenerative disease caused by a GAA triplet repeat expansion in the first intron of the frataxin gene, which results in reduced expression levels of the corresponding protein. Despite numerous animal and cellular models, therapeutic options that mechanistically address impaired frataxin expression are lacking. Here, we have developed a new mammalian cell model employing the Cre/loxP recombination system to induce a homozygous or heterozygous frataxin knockout in mouse embryonic fibroblasts. Induction of Cre-mediated disruption by tamoxifen was successfully tested on RNA and protein levels. After loss of frataxin protein, cell division, aconitase activity and oxygen consumption rates were found to be decreased, while ROS production was increased in the homozygous state. By contrast, in the heterozygous state no such changes were observed. A time-resolved analysis revealed the loss of aconitase activity as an initial event after induction of complete frataxin deficiency, followed by secondarily elevated ROS production and a late increase in iron content. Initial impairments of oxygen consumption and ATP production were found to be compensated in the late state and seemed to play a minor role in Friedreich ataxia pathophysiology. In conclusion and as predicted from its proposed role in iron sulfur cluster (ISC) biosynthesis, disruption of frataxin primarily causes impaired function of ISC-containing enzymes, whereas other consequences, including elevated ROS production and iron accumulation, appear secondary. These parameters and the robustness of the newly established system may additionally be used for a time-resolved study of pharmacological candidates in a HTS manner. Summary: The use of a new mammalian cell model with inducible homozygous and heterozygous frataxin knockout allows new insights into the chronology and causes of the disease Friedreich ataxia.
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Affiliation(s)
- Dörte Poburski
- Institute of Nutrition, Friedrich Schiller University (FSU) Jena, Dornburgerstraße 24, Jena D-07743, Germany
| | - Josefine Barbara Boerner
- Institute of Nutrition, Friedrich Schiller University (FSU) Jena, Dornburgerstraße 24, Jena D-07743, Germany
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares EA7402, Institut Universitaire de Recherche Clinique, Université de Montpellier, Montpellier F-34093, France
| | - Michael Ristow
- Institute of Nutrition, Friedrich Schiller University (FSU) Jena, Dornburgerstraße 24, Jena D-07743, Germany
| | - René Thierbach
- Institute of Nutrition, Friedrich Schiller University (FSU) Jena, Dornburgerstraße 24, Jena D-07743, Germany
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25
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Liddell JR. Targeting mitochondrial metal dyshomeostasis for the treatment of neurodegeneration. Neurodegener Dis Manag 2015; 5:345-64. [DOI: 10.2217/nmt.15.19] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial impairment and metal dyshomeostasis are suggested to be associated with many neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and Friedreich's ataxia. Treatments aimed at restoring metal homeostasis are highly effective in models of these diseases, and clinical trials hold promise. However, in general, the effect of these treatments on mitochondrial metal homeostasis is unclear, and the contribution of mitochondrial metal dyshomeostasis to disease pathogenesis requires further investigation. This review describes the role of metals in mitochondria in health, how mitochondrial metals are disrupted in neurodegenerative diseases, and potential therapeutics aimed at restoring mitochondrial metal homeostasis and function.
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Affiliation(s)
- Jeffrey R Liddell
- Department of Pathology, University of Melbourne, Victoria 3010, Australia
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26
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Mena NP, Urrutia PJ, Lourido F, Carrasco CM, Núñez MT. Mitochondrial iron homeostasis and its dysfunctions in neurodegenerative disorders. Mitochondrion 2015; 21:92-105. [PMID: 25667951 DOI: 10.1016/j.mito.2015.02.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/13/2015] [Accepted: 02/02/2015] [Indexed: 12/17/2022]
Abstract
Synthesis of the iron-containing prosthetic groups-heme and iron-sulfur clusters-occurs in mitochondria. The mitochondrion is also an important producer of reactive oxygen species (ROS), which are derived from electrons leaking from the electron transport chain. The coexistence of both ROS and iron in the secluded space of the mitochondrion makes this organelle particularly prone to oxidative damage. Here, we review the elements that configure mitochondrial iron homeostasis and discuss the principles of iron-mediated ROS generation in mitochondria. We also review the evidence for mitochondrial dysfunction and iron accumulation in Alzheimer's disease, Huntington Disease, Friedreich's ataxia, and in particular Parkinson's disease. We postulate that a positive feedback loop of mitochondrial dysfunction, iron accumulation, and ROS production accounts for the process of cell death in various neurodegenerative diseases in which these features are present.
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Affiliation(s)
- Natalia P Mena
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Pamela J Urrutia
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Fernanda Lourido
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Carlos M Carrasco
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Marco T Núñez
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile.
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27
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Iommarini L, Peralta S, Torraco A, Diaz F. Mitochondrial Diseases Part II: Mouse models of OXPHOS deficiencies caused by defects in regulatory factors and other components required for mitochondrial function. Mitochondrion 2015; 22:96-118. [PMID: 25640959 DOI: 10.1016/j.mito.2015.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 01/22/2015] [Indexed: 01/21/2023]
Abstract
Mitochondrial disorders are defined as defects that affect the oxidative phosphorylation system (OXPHOS). They are characterized by a heterogeneous array of clinical presentations due in part to a wide variety of factors required for proper function of the components of the OXPHOS system. There is no cure for these disorders owing to our poor knowledge of the pathogenic mechanisms of disease. To understand the mechanisms of human disease numerous mouse models have been developed in recent years. Here we summarize the features of several mouse models of mitochondrial diseases directly related to those factors affecting mtDNA maintenance, replication, transcription, translation as well as other proteins that are involved in mitochondrial dynamics and quality control which affect mitochondrial OXPHOS function without being intrinsic components of the system. We discuss how these models have contributed to our understanding of mitochondrial diseases and their pathogenic mechanisms.
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Affiliation(s)
- Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40128 Bologna, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15 - 00146, Rome, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
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28
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Friedreich's Ataxia: A Neuronal Point of View on the Oxidative Stress Hypothesis. Antioxidants (Basel) 2014; 3:592-603. [PMID: 26785073 PMCID: PMC4665420 DOI: 10.3390/antiox3030592] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 05/06/2014] [Accepted: 05/16/2014] [Indexed: 12/02/2022] Open
Abstract
A prominent feature of Friedreich’s ataxia (FRDA) is the neurodegeneration of the central and peripheral nervous systems, but little information is available about the mechanisms leading to neuronal damage in this pathology. Currently, no treatments delay, prevent, or reverse the inexorable decline that occurs in this condition. Evidence of oxidative damage has been demonstrated in Friedreich’s ataxia, and this damage has been proposed as the origin of the disease. Nevertheless, the role of oxidative stress in FRDA remains debatable. The lack of direct evidence of reactive oxygen species overproduction in FRDA cells and tissues and the failure of exogenous antioxidants to rescue FRDA phenotypes questions the role of oxidative stress in this pathology. For example, the antioxidant “idebenone” ameliorates cardiomyopathy in FRDA patients, but this therapy does not improve neurodegeneration. To date, no known pharmacological treatment with antioxidant properties cures or delays FRDA neuropathology. This review reports and discusses the evidence of oxidative stress in FRDA and focuses on the existing knowledge of the apparent ineffectiveness of antioxidants for the treatment of neuronal damage.
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29
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Lee YK, Ho PWL, Schick R, Lau YM, Lai WH, Zhou T, Li Y, Ng KM, Ho SL, Esteban MA, Binah O, Tse HF, Siu CW. Modeling of Friedreich ataxia-related iron overloading cardiomyopathy using patient-specific-induced pluripotent stem cells. Pflugers Arch 2014; 466:1831-44. [PMID: 24327207 DOI: 10.1007/s00424-013-1414-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/07/2013] [Accepted: 11/28/2013] [Indexed: 11/24/2022]
Abstract
Friedreich ataxia (FRDA), a recessive neurodegenerative disorder commonly associated with hypertrophic cardiomyopathy, is due to GAA repeat expansions within the first intron of the frataxin (FXN) gene encoding the mitochondrial protein involved in iron-sulfur cluster biosynthesis. The triplet codon repeats lead to heterochromatin-mediated gene silencing and loss of frataxin. Nevertheless, inadequacy of existing FRDA-cardiac cellular models limited cardiomyopathy studies. We tested the hypothesis that iron homeostasis deregulation accelerates reduction in energy synthesis dynamics which contributes to impaired cardiac calcium homeostasis and contractile force. Silencing of FXN expressions occurred both in somatic FRDA-skin fibroblasts and two of the induced pluripotent stem cells (iPSC) clones; a sign of stress condition was shown in FRDA-iPSC cardiomyocytes with disorganized mitochondrial network and mitochondrial DNA (mtDNA) depletion; hypertrophic cardiac stress responses were observed by an increase in α-actinin-positive cell sizes revealed by FACS analysis as well as elevation in brain natriuretic peptide (BNP) gene expression; the intracellular iron accumulated in FRDA cardiomyocytes might be due to attenuated negative feedback response of transferring receptor (TSFR) expression and positive feedback response of ferritin (FTH1); energy synthesis dynamics, in terms of ATP production rate, was impaired in FRDA-iPSC cardiomyocytes, which were prone to iron overload condition. Energetic insufficiency determined slower Ca(2+) transients by retarding calcium reuptake to sarcoplasmic reticulum (SR) and impaired the positive inotropic and chronotropic responses to adrenergic stimulation. Our data showed for the first time that FRDA-iPSCs cardiac derivatives represent promising models to study cardiac stress response due to impaired iron homeostasis condition and mitochondrial damages. The cardiomyopathy phenotype was accelerated in an iron-overloaded condition early in calcium homeostasis aspect.
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Affiliation(s)
- Yee-Ki Lee
- Cardiology Division, Department of Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong, China
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30
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Abstract
SIGNIFICANCE Iron is the most abundant transition metal in biology and an essential cofactor for many cellular enzymes. Iron homeostasis impairment is also a component of peripheral neuropathies. RECENT ADVANCES During the past years, much effort has been paid to understand the molecular mechanism involved in maintaining systemic iron homeostasis in mammals. This has been stimulated by the evidence that iron dyshomeostasis is an initial cause of several disorders, including genetic and sporadic neurodegenerative disorders. CRITICAL ISSUES However, very little has been done to investigate the physiological role of iron in peripheral nervous system (PNS), despite the development of suitable cellular and animal models. FUTURE DIRECTIONS To stimulate research on iron metabolism and peripheral neuropathy, we provide a summary of the knowledge on iron homeostasis in the PNS, on its transport across the blood-nerve barrier, its involvement in myelination, and we identify unresolved questions. Furthermore, we comment on the role of iron in iron-related disorder with peripheral component, in demyelinating and metabolic peripheral neuropathies.
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Affiliation(s)
- Sonia Levi
- 1 University Vita-Salute San Raffaele , Milan, Italy
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31
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Obis È, Irazusta V, Sanchís D, Ros J, Tamarit J. Frataxin deficiency in neonatal rat ventricular myocytes targets mitochondria and lipid metabolism. Free Radic Biol Med 2014; 73:21-33. [PMID: 24751525 DOI: 10.1016/j.freeradbiomed.2014.04.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 04/04/2014] [Accepted: 04/04/2014] [Indexed: 11/21/2022]
Abstract
Friedreich ataxia (FRDA) is a hereditary disease caused by deficient frataxin expression. This mitochondrial protein has been related to iron homeostasis, energy metabolism, and oxidative stress. Patients with FRDA experience neurologic alterations and cardiomyopathy, which is the leading cause of death. The specific effects of frataxin depletion on cardiomyocytes are poorly understood because no appropriate cardiac cellular model is available to researchers. To address this research need, we present a model based on primary cultures of neonatal rat ventricular myocytes (NRVMs) and short-hairpin RNA interference. Using this approach, frataxin was reduced down to 5 to 30% of control protein levels after 7 days of transduction. At this stage the activity and amount of the iron-sulfur protein aconitase, in vitro activities of several OXPHOS components, levels of iron-regulated mRNAs, and the ATP/ADP ratio were comparable to controls. However, NRVMs exhibited markers of oxidative stress and a disorganized mitochondrial network with enlarged mitochondria. Lipids, the main energy source of heart cells, also underwent a clear metabolic change, indicated by the increased presence of lipid droplets and induction of medium-chain acyl-CoA dehydrogenase. These results indicate that mitochondria and lipid metabolism are primary targets of frataxin deficiency in NRVMs. Therefore, they contribute to the understanding of cardiac-specific mechanisms occurring in FRDA and give clues for the design of cardiac-specific treatment strategies for FRDA.
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MESH Headings
- Aconitate Hydratase/metabolism
- Animals
- Cardiomyopathies/pathology
- Cells, Cultured
- Disease Models, Animal
- Friedreich Ataxia/pathology
- Heart Ventricles/cytology
- Heart Ventricles/metabolism
- Humans
- Iron-Binding Proteins/genetics
- Lipid Metabolism/genetics
- Membrane Potential, Mitochondrial/physiology
- Mitochondria, Heart/genetics
- Mitochondria, Heart/metabolism
- Mitochondria, Heart/pathology
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Oxidative Stress/physiology
- Peroxisome Proliferator-Activated Receptors/metabolism
- RNA Interference
- RNA, Small Interfering
- Rats
- Rats, Sprague-Dawley
- Frataxin
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Affiliation(s)
- Èlia Obis
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, 25198 Lleida, Spain
| | - Verónica Irazusta
- Instituto de Investigación para la Industria Química, INIQUI-CONICET, Salta, Argentina
| | - Daniel Sanchís
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, 25198 Lleida, Spain
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, 25198 Lleida, Spain
| | - Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, 25198 Lleida, Spain.
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Puccio H, Anheim M, Tranchant C. Pathophysiogical and therapeutic progress in Friedreich ataxia. Rev Neurol (Paris) 2014; 170:355-65. [PMID: 24792433 DOI: 10.1016/j.neurol.2014.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 01/10/2023]
Abstract
Friedreich ataxia (FRDA) is the most common hereditary autosomal recessive ataxia, but is also a multisystemic condition with frequent presence of cardiomyopathy or diabetes. It has been linked to expansion of a GAA-triplet repeat in the first intron of the FXN gene, leading to a reduced level of frataxin, a mitochondrial protein which, by controlling both iron entry and/or sulfide production, is essential to properly assemble and protect the Fe-S cluster during the initial stage of biogenesis. Several data emphasize the role of oxidative damage in FRDA, but better understanding of pathophysiological consequences of FXN mutations has led to develop animal models. Conditional knockout models recapitulate important features of the human disease but lack the genetic context, GAA repeat expansion-based knock-in and transgenic models carry a GAA repeat expansion but they only show a very mild phenotype. Cells derived from FRDA patients constitute the most relevant frataxin-deficient cell model as they carry the complete frataxin locus together with GAA repeat expansions and regulatory sequences. Induced pluripotent stem cell (iPSC)-derived neurons present a maturation delay and lower mitochondrial membrane potential, while cardiomyocytes exhibit progressive mitochondrial degeneration, with frequent dark mitochondria and proliferation/accumulation of normal mitochondria. Efforts in developing therapeutic strategies can be divided into three categories: iron chelators, antioxidants and/or stimulants of mitochondrial biogenesis, and frataxin level modifiers. A promising therapeutic strategy that is currently the subject of intense research is to directly target the heterochromatin state of the GAA repeat expansion with histone deacytelase inhibitors (HDACi) to restore frataxin levels.
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Affiliation(s)
- H Puccio
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Collège de France, chaire de génétique humaine, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France
| | - M Anheim
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Service de neurologie, unité des pathologies du mouvement, hôpital de Hautepierre, hôpital universitaire, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - C Tranchant
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Service de neurologie, unité des pathologies du mouvement, hôpital de Hautepierre, hôpital universitaire, 1, place de l'Hôpital, 67000 Strasbourg, France.
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Anzovino A, Lane DJR, Huang MLH, Richardson DR. Fixing frataxin: 'ironing out' the metabolic defect in Friedreich's ataxia. Br J Pharmacol 2014; 171:2174-90. [PMID: 24138602 PMCID: PMC3976629 DOI: 10.1111/bph.12470] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/17/2013] [Accepted: 10/07/2013] [Indexed: 12/14/2022] Open
Abstract
The metabolically active and redox-active mitochondrion appears to play a major role in the cellular metabolism of the transition metal, iron. Frataxin, a mitochondrial matrix protein, has been identified as playing a key role in the iron metabolism of this organelle due to its iron-binding properties and is known to be essential for iron-sulphur cluster formation. However, the precise function of frataxin remains elusive. The decrease in frataxin expression, as seen in the inherited disorder Friedreich's ataxia, markedly alters cellular and mitochondrial iron metabolism in both the mitochondrion and the cell. The resulting dysregulation of iron trafficking damages affects tissues leading to neuro- and cardiodegeneration. This disease underscores the importance of iron homeostasis in the redox-active environment of the mitochondrion and the molecular players involved. Unravelling the mechanisms of altered iron metabolism in Friedreich's ataxia will help elucidate a biochemical function for frataxin. Consequently, this will enable the development of more effective and rationally designed treatments. This review will focus on the emerging function of frataxin in relation to the observed alterations in mitochondrial iron metabolism in Friedreich's ataxia. Tissue-specific alterations due to frataxin loss will also be discussed, as well as current and emerging therapeutic strategies.
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Affiliation(s)
- A Anzovino
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of SydneySydney, NSW, Australia
| | - D J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of SydneySydney, NSW, Australia
| | | | - D R Richardson
- Correspondence Professor D R Richardson, Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia. E-mail:
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Lynch DR, Regner SR, Schadt KA, Friedman LS, Lin KY, Sutton MGSJ. Management and therapy for cardiomyopathy in Friedreich’s ataxia. Expert Rev Cardiovasc Ther 2014; 10:767-77. [DOI: 10.1586/erc.12.57] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Bayot A, Rustin P. Friedreich's ataxia, frataxin, PIP5K1B: echo of a distant fracas. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:725635. [PMID: 24194977 PMCID: PMC3806116 DOI: 10.1155/2013/725635] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/12/2013] [Indexed: 01/15/2023]
Abstract
"Frataxin fracas" were the words used when referring to the frataxin-encoding gene (FXN) burst in as a motive to disqualify an alternative candidate gene, PIP5K1B, as an actor in Friedreich's ataxia (FRDA) (Campuzano et al., 1996; Cossee et al., 1997; Carvajal et al., 1996). The instrumental role in the disease of large triplet expansions in the first intron of FXN has been thereafter fully confirmed, and this no longer suffers any dispute (Koeppen, 2011). On the other hand, a recent study suggests that the consequences of these large expansions in FXN are wider than previously thought and that the expression of surrounding genes, including PIP5K1B, could be concurrently modulated by these large expansions (Bayot et al., 2013). This recent observation raises a number of important and yet unanswered questions for scientists and clinicians working on FRDA; these questions are the substratum of this paper.
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Affiliation(s)
- Aurélien Bayot
- INSERM UMR 676, Bâtiment Ecran, Hôpital Robert Debré, 48 boulevard Sérurier, 75019 Paris, France
- Université Paris 7, Faculté de Médecine Denis Diderot, Site Robert Debré, 48 boulevard Sérurier, 75019 Paris, France
| | - Pierre Rustin
- INSERM UMR 676, Bâtiment Ecran, Hôpital Robert Debré, 48 boulevard Sérurier, 75019 Paris, France
- Université Paris 7, Faculté de Médecine Denis Diderot, Site Robert Debré, 48 boulevard Sérurier, 75019 Paris, France
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González-Cabo P, Palau F. Mitochondrial pathophysiology in Friedreich's ataxia. J Neurochem 2013; 126 Suppl 1:53-64. [PMID: 23859341 DOI: 10.1111/jnc.12303] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/09/2013] [Accepted: 05/08/2013] [Indexed: 12/01/2022]
Abstract
Neurological examination indicates that Friedreich's ataxia corresponds to a mixed sensory and cerebellar ataxia, which affects the proprioceptive pathways. Neuropathology and pathophysiology of Friedreich's ataxia involves the peripheral sensory nerves, dorsal root ganglia, posterior columns, the spinocerebellar, and corticospinal tracts of the spinal cord, gracile and cuneate nuclei, dorsal nuclei of Clarke, and the dentate nucleus. Involvement of the myocardium and pancreatic islets of Langerhans indicates that it is also a systemic disease. The pathophysiology of the disease is the consequence of frataxin deficiency in the mitochondria and cells. Some of the biological consequences are currently recognized such as the effects on iron-sulfur cluster biogenesis or the oxidative status, but others deserve to be studied in depth. Among physiological aspects of mitochondria that have been associated with neurodegeneration and may be interesting to investigate in Friedreich's ataxia we can include mitochondrial dynamics and movement, communication with other organelles especially the endoplasmic reticulum, calcium homeostasis, apoptosis, and mitochondrial biogenesis and quality control. Changes in the mitochondrial physiology and transport in peripheral and central axons and mitochondrial metabolic functions such as bioenergetics and energy delivery in the synapses are also relevant functions to be considered. Thus, to understand the general pathophysiology of the disease and fundamental pathogenic mechanisms such as dying-back axonopathy, and determine molecular, cellular and tissue therapeutic targets, we need to discover the effect of frataxin depletion on mitochondrial properties and on specific cell susceptibility in the nervous system and other affected organs.
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Affiliation(s)
- Pilar González-Cabo
- Program in Rare and Genetic Diseases, Centro de Investigación Príncipe Felipe, Valencia, Spain
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Perdomini M, Hick A, Puccio H, Pook MA. Animal and cellular models of Friedreich ataxia. J Neurochem 2013; 126 Suppl 1:65-79. [PMID: 23859342 DOI: 10.1111/jnc.12219] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 11/30/2022]
Abstract
The development and use of animal and cellular models of Friedreich ataxia (FRDA) are essential requirements for the understanding of FRDA disease mechanisms and the investigation of potential FRDA therapeutic strategies. Although animal and cellular models of lower organisms have provided valuable information on certain aspects of FRDA disease and therapy, it is intuitive that the most useful models are those of mammals and mammalian cells, which are the closest in physiological terms to FRDA patients. To date, there have been considerable efforts put into the development of several different FRDA mouse models and relevant FRDA mouse and human cell line systems. We summarize the principal mammalian FRDA models, discuss the pros and cons of each system, and describe the ways in which such models have been used to address two of the fundamental, as yet unanswered, questions regarding FRDA. Namely, what is the exact pathophysiology of FRDA and what is the detailed genetic and epigenetic basis of FRDA?
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Affiliation(s)
- Morgane Perdomini
- Translational Medecine and Neurogenetics, IGBMC-Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
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Lane DJR, Huang MLH, Ting S, Sivagurunathan S, Richardson DR. Biochemistry of cardiomyopathy in the mitochondrial disease Friedreich's ataxia. Biochem J 2013; 453:321-36. [PMID: 23849057 DOI: 10.1042/bj20130079] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
FRDA (Friedreich's ataxia) is a debilitating mitochondrial disorder leading to neural and cardiac degeneration, which is caused by a mutation in the frataxin gene that leads to decreased frataxin expression. The most common cause of death in FRDA patients is heart failure, although it is not known how the deficiency in frataxin potentiates the observed cardiomyopathy. The major proposed biochemical mechanisms for disease pathogenesis and the origins of heart failure in FRDA involve metabolic perturbations caused by decreased frataxin expression. Additionally, recent data suggest that low frataxin expression in heart muscle of conditional frataxin knockout mice activates an integrated stress response that contributes to and/or exacerbates cardiac hypertrophy and the loss of cardiomyocytes. The elucidation of these potential mechanisms will lead to a more comprehensive understanding of the pathogenesis of FRDA, and will contribute to the development of better treatments and therapeutics.
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Affiliation(s)
- Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building, D06, University of Sydney, Sydney, NSW 2006, Australia
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Bayot A, Reichman S, Lebon S, Csaba Z, Aubry L, Sterkers G, Husson I, Rak M, Rustin P. Cis-silencing of PIP5K1B evidenced in Friedreich's ataxia patient cells results in cytoskeleton anomalies. Hum Mol Genet 2013; 22:2894-904. [PMID: 23552101 DOI: 10.1093/hmg/ddt144] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Friedreich's ataxia (FRDA) is a progressive neurodegenerative disease characterized by ataxia, variously associating heart disease, diabetes mellitus and/or glucose intolerance. It results from intronic expansion of GAA triplet repeats at the FXN locus. Homozygous expansions cause silencing of the FXN gene and subsequent decreased expression of the encoded mitochondrial frataxin. Detailed analyses in fibroblasts and neuronal tissues from FRDA patients have revealed profound cytoskeleton anomalies. So far, however, the molecular mechanism underlying these cytoskeleton defects remains unknown. We show here that gene silencing spreads in cis over the PIP5K1B gene in cells from FRDA patients (circulating lymphocytes and primary fibroblasts), correlating with expanded GAA repeat size. PIP5K1B encodes phosphatidylinositol 4-phosphate 5-kinase β type I (pip5k1β), an enzyme functionally linked to actin cytoskeleton dynamics that phosphorylates phosphatidylinositol 4-phosphate [PI(4)P] to generate phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. Accordingly, loss of pip5k1β function in FRDA cells was accompanied by decreased PI(4,5)P2 levels and was shown instrumental for destabilization of the actin network and delayed cell spreading. Knockdown of PIP5K1B in control fibroblasts using shRNA reproduced abnormal actin cytoskeleton remodeling, whereas over-expression of PIP5K1B, but not FXN, suppressed this phenotype in FRDA cells. In addition to provide new insights into the consequences of the FXN gene expansion, these findings raise the question whether PIP5K1B silencing may contribute to the variable manifestation of this complex disease.
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Affiliation(s)
- Aurélien Bayot
- Hôpital Robert Debré, INSERM UMR 676 Faculté de Médecine Denis Diderot, Université Paris 7, 75019 Paris, France.
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Gomes CM, Santos R. Neurodegeneration in Friedreich's ataxia: from defective frataxin to oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:487534. [PMID: 23936609 PMCID: PMC3725840 DOI: 10.1155/2013/487534] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 06/14/2013] [Indexed: 02/08/2023]
Abstract
Friedreich's ataxia is the most common inherited autosomal recessive ataxia and is characterized by progressive degeneration of the peripheral and central nervous systems and cardiomyopathy. This disease is caused by the silencing of the FXN gene and reduced levels of the encoded protein, frataxin. Frataxin is a mitochondrial protein that functions primarily in iron-sulfur cluster synthesis. This small protein with an α / β sandwich fold undergoes complex processing and imports into the mitochondria, generating isoforms with distinct N-terminal lengths which may underlie different functionalities, also in respect to oligomerization. Missense mutations in the FXN coding region, which compromise protein folding, stability, and function, are found in 4% of FRDA heterozygous patients and are useful to understand how loss of functional frataxin impacts on FRDA physiopathology. In cells, frataxin deficiency leads to pleiotropic phenotypes, including deregulation of iron homeostasis and increased oxidative stress. Increasing amount of data suggest that oxidative stress contributes to neurodegeneration in Friedreich's ataxia.
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Affiliation(s)
- Cláudio M. Gomes
- Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2784-505 Oeiras, Portugal
| | - Renata Santos
- Development of the Nervous System, IBENS, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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Vaubel RA, Isaya G. Iron-sulfur cluster synthesis, iron homeostasis and oxidative stress in Friedreich ataxia. Mol Cell Neurosci 2013; 55:50-61. [PMID: 22917739 PMCID: PMC3530001 DOI: 10.1016/j.mcn.2012.08.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/01/2012] [Accepted: 08/05/2012] [Indexed: 12/21/2022] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive, multi-systemic degenerative disease that results from reduced synthesis of the mitochondrial protein frataxin. Frataxin has been intensely studied since its deficiency was linked to FRDA in 1996. The defining properties of frataxin - (i) the ability to bind iron, (ii) the ability to interact with, and donate iron to, other iron-binding proteins, and (iii) the ability to oligomerize, store iron and control iron redox chemistry - have been extensively characterized with different frataxin orthologs and their interacting protein partners. This very large body of biochemical and structural data [reviewed in (Bencze et al., 2006)] supports equally extensive biological evidence that frataxin is critical for mitochondrial iron metabolism and overall cellular iron homeostasis and antioxidant protection [reviewed in (Wilson, 2006)]. However, the precise biological role of frataxin remains a matter of debate. Here, we review seminal and recent data that strongly link frataxin to the synthesis of iron-sulfur cluster cofactors (ISC), as well as controversial data that nevertheless link frataxin to additional iron-related processes. Finally, we discuss how defects in ISC synthesis could be a major (although likely not unique) contributor to the pathophysiology of FRDA via (i) loss of ISC-dependent enzymes, (ii) mitochondrial and cellular iron dysregulation, and (iii) enhanced iron-mediated oxidative stress. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Rachael A Vaubel
- Department of Pediatric & Adolescent Medicine and the Mayo Clinic Children's Center, Mayo Clinic, Rochester, MN 55905, USA
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Koeppen AH, Kuntzsch EC, Bjork ST, Ramirez RL, Mazurkiewicz JE, Feustel PJ. Friedreich ataxia: metal dysmetabolism in dorsal root ganglia. Acta Neuropathol Commun 2013; 1:26. [PMID: 24252376 PMCID: PMC3893523 DOI: 10.1186/2051-5960-1-26] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 06/16/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Friedreich ataxia (FA) causes distinctive lesions of dorsal root ganglia (DRG), including neuronal atrophy, satellite cell hyperplasia, and absorption of dying nerve cells into residual nodules. Two mechanisms may be involved: hypoplasia of DRG neurons from birth and superimposed iron (Fe)- and zinc (Zn)-mediated oxidative injury. This report presents a systematic analysis of DRG in 7 FA patients and 13 normal controls by X-ray fluorescence (XRF) of polyethylene glycol-embedded DRG; double-label confocal immunofluorescence microscopy of Zn- and Fe-related proteins; and immunohistochemistry of frataxin and the mitochondrial marker, ATP synthase F1 complex V β-polypeptide (ATP5B). RESULTS XRF revealed normal total Zn- and Fe-levels in the neural tissue of DRG in FA (mean ± standard deviation): Zn=5.46±2.29 μg/ml, Fe=19.99±13.26 μg/ml in FA; Zn=8.16±6.19 μg/ml, Fe=23.85±12.23 μg/ml in controls. Despite these unchanged total metal concentrations, Zn- and Fe-related proteins displayed major shifts in their cellular localization. The Zn transporter Zip14 that is normally expressed in DRG neurons and satellite cells became more prominent in hyperplastic satellite cells and residual nodules. Metallothionein 3 (MT3) stains confirmed reduction of neuronal size in FA, but MT3 expression remained low in hyperplastic satellite cells. In contrast, MT1/2 immunofluorescence was prominent in proliferating satellite cells. Neuronal ferritin immunofluorescence declined but remained strong in hyperplastic satellite cells and residual nodules. Satellite cells in FA showed a larger number of mitochondria expressing ATB5B. Frataxin immunohistochemistry in FA confirmed small neuronal sizes, irregular distribution of reaction product beneath the plasma membrane, and enhanced expression in hyperplastic satellite cells. CONCLUSIONS The pool of total cellular Zn in normal DRG equals 124.8 μM, which is much higher than needed for the proper function of Zn ion-dependent proteins. It is likely that any disturbance of Zn buffering by Zip14 and MT3 causes mitochondrial damage and cell death. In contrast to Zn, sequestration of Fe in hyperplastic satellite cells may represent a protective mechanism. The changes in the cellular localization of Zn- and Fe-handling proteins suggest metal transfer from degenerating DRG neurons to activated satellite cells and connect neuronal metal dysmetabolism with the pathogenesis of the DRG lesion in FA.
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Affiliation(s)
- Arnulf H Koeppen
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
- Neurology Service, Veterans Affairs Medical Center, Albany, NY 12208, USA
- Department of Neurology, Albany Medical College, Albany, NY 12208, USA
- Department of Pathology, Albany Medical College, Albany, NY 12208, USA
| | - Erik C Kuntzsch
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
| | - Sarah T Bjork
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
| | - R Liane Ramirez
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
| | - Joseph E Mazurkiewicz
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Paul J Feustel
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
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Koeppen AH, Ramirez RL, Yu D, Collins SE, Qian J, Parsons PJ, Yang KX, Chen Z, Mazurkiewicz JE, Feustel PJ. Friedreich's ataxia causes redistribution of iron, copper, and zinc in the dentate nucleus. THE CEREBELLUM 2013; 11:845-60. [PMID: 22562713 PMCID: PMC3497958 DOI: 10.1007/s12311-012-0383-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Friedreich's ataxia (FRDA) causes selective atrophy of the large neurons of the dentate nucleus (DN). High iron (Fe) concentration and failure to clear the metal from the affected brain tissue are potential risk factors in the progression of the lesion. The DN also contains relatively high amounts of copper (Cu) and zinc (Zn), but the importance of these metals in FRDA has not been established. This report describes nondestructive quantitative X-ray fluorescence (XRF) and "mapping" of Fe, Cu, and Zn in polyethylene glycol–dimethylsulfoxide (PEG/DMSO)-embedded DN of 10 FRDA patients and 13 controls. Fe fluorescence arose predominantly from the hilar white matter, whereas Cu and Zn were present at peak levels in DN gray matter. Despite collapse of the DN in FRDA, the location of the peak Fe signal did not change. In contrast, the Cu and Zn regions broadened and overlapped extensively with the Fe-rich region. Maximal metal concentrations did not differ from normal (in micrograms per milliliter of solid PEG/DMSO as means ± S.D.): Fe normal, 364 ± 117, FRDA, 344 ± 159; Cu normal, 33 ± 13, FRDA, 33 ± 18; and Zn normal, 32 ± 16, FRDA, 33 ± 19. Tissues were recovered from PEG/DMSO and transferred into paraffin for matching with immunohistochemistry of neuron-specific enolase (NSE), glutamic acid decarboxylase (GAD), and ferritin. NSE and GAD reaction products confirmed neuronal atrophy and grumose degeneration that coincided with abnormally diffuse Cu and Zn zones. Ferritin immunohistochemistry matched Fe XRF maps, revealing the most abundant reaction product in oligodendroglia of the DN hilus. In FRDA, these cells were smaller and more numerous than normal. In the atrophic DN gray matter of FRDA, anti-ferritin labeled mostly hypertrophic microglia. Immunohistochemistry and immunofluorescence of the Cu-responsive proteins Cu,Zn-superoxide dismutase and Cu++-transporting ATPase α-peptide did not detect specific responses to Cu redistribution in FRDA. In contrast, metallothionein (MT)-positive processes were more abundant than normal and contributed to the gliosis of the DN. The isoforms of MT, MT-1/2, and brain-specific MT-3 displayed only limited co-localization with glial fibrillary acidic protein. The results suggest that MT can provide effective protection against endogenous Cu and Zn toxicity in FRDA, similar to the neuroprotective sequestration of Fe in holoferritin.
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Affiliation(s)
- Arnulf H Koeppen
- Research Service (151), Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY, 12208, USA.
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Abstract
Transition metals are frequently used as cofactors for enzymes and oxygen-carrying proteins that take advantage of their propensity to gain and lose single electrons. Metals are particularly important in mitochondria, where they play essential roles in the production of ATP and detoxification of reactive oxygen species. At the same time, transition metals (particularly Fe and Cu) can promote the formation of harmful radicals, necessitating meticulous control of metal concentration and subcellular compartmentalization. We summarize our current understanding of Fe and Cu in mammalian mitochondrial biology and discuss human diseases associated with aberrations in mitochondrial metal homeostasis.
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Abstract
Friedreich ataxia is an autosomal recessive disorder that affects children and young adults. The mutation consists of a homozygous guanine-adenine-adenine trinucleotide repeat expansion that causes deficiency of frataxin, a small nuclear genome-encoded mitochondrial protein. Low frataxin levels lead to insufficient biosynthesis of iron-sulfur clusters that are required for mitochondrial electron transport and assembly of functional aconitase, and iron dysmetabolism of the entire cell. This review of the neuropathology of Friedreich ataxia stresses the critical role of hypoplasia and superimposed atrophy of dorsal root ganglia. Progressive destruction of dorsal root ganglia accounts for thinning of dorsal roots, degeneration of dorsal columns, transsynaptic atrophy of nerve cells in Clarke column and dorsal spinocerebellar fibers, atrophy of gracile and cuneate nuclei, and neuropathy of sensory nerves. The lesion of the dentate nucleus consists of progressive and selective atrophy of large glutamatergic neurons and grumose degeneration of corticonuclear synaptic terminals that contain γ-aminobutyric acid (GABA). Small GABA-ergic neurons and their projection fibers in the dentato-olivary tract survive. Atrophy of Betz cells and corticospinal tracts constitute a second intrinsic CNS lesion. In light of the selective vulnerability of organs and tissues to systemic frataxin deficiency, many questions about the pathogenesis of Friedreich ataxia remain.
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Affiliation(s)
- Arnulf H Koeppen
- Research Service, Veterans Affairs Medical Center, Albany, New York 12208, USA.
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Ramirez RL, Qian J, Santambrogio P, Levi S, Koeppen AH. Relation of cytosolic iron excess to cardiomyopathy of Friedreich's ataxia. Am J Cardiol 2012; 110:1820-7. [PMID: 23000103 DOI: 10.1016/j.amjcard.2012.08.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 08/10/2012] [Accepted: 08/10/2012] [Indexed: 12/22/2022]
Abstract
Cardiomyopathy is the leading cause of death in Friedreich's ataxia. This autosomal recessive disease is caused by a homozygous guanine-adenine-adenine trinucleotide repeat expansion in the frataxin gene (chromosome 9q21). One untoward effect of frataxin deficiency is the lack of iron (Fe)-sulfur clusters. Progressive remodeling of the heart in FA, however, may be more specifically related to sarcoplasmic Fe overload. The Fe-containing inclusions in a small percentage of cardiomyocytes may not represent purely mitochondrial accumulation of the metal. The objective of the present study was to re-examine the contribution of Fe to cardiomyocyte hypertrophy, fiber necrosis, and myocardial scarring, using a combination of X-ray fluorescence, slide histochemistry of Fe, and immunohistochemistry of 2 Fe-related proteins. Polyethylene glycol-embedded human cardiac tissues from the left and right ventricular walls, ventricular septum, right atrium, and atrial septum were studied using qualitative and quantitative X-ray fluorescence. Tissues were recovered from the polyethylene glycol matrix, re-embedded in paraffin, and sectioned for visualization of Fe, ferritin, and ferroportin. X-ray fluorescence showed quantifiable levels of Fe and zinc. Regions of significantly increased Fe (1 to 4 mm(2)) were irregularly distributed throughout the working myocardium. Fe granules were sparse in conductive tissue. Zinc signals remained unchanged. Robust cytosolic ferritin reaction product occurred in many fibers of the affected regions. Ferroportin displayed no response except in fibers with advanced Fe overload. These observations are at variance with the concept of selective Fe overload only in cardiac mitochondria. In conclusion, Fe-mediated damage to cardiomyocytes and myocardial scarring are more likely due to cytosolic Fe excess.
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Dey R, Kemp K, Gray E, Rice C, Scolding N, Wilkins A. Human mesenchymal stem cells increase anti-oxidant defences in cells derived from patients with Friedreich's ataxia. CEREBELLUM (LONDON, ENGLAND) 2012; 11:861-71. [PMID: 22826109 DOI: 10.1007/s12311-012-0406-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Friedreich's ataxia (FRDA) is a progressive neurodegenerative disorder which is, at present, incurable. Oxidative damage and inhibition of mitochondrial function are key determinants of cellular damage in FRDA, since there is greater sensitivity to oxidative stress in cells with frataxin deficiency. In addition, frataxin-deficient cells have an impaired ability to recruit antioxidant defences against endogenous oxidative stress. We have recently shown that factors derived from bone marrow-derived mesenchymal stem cells (MSCs) increase hydrogen peroxide scavenging enzymes and offer protection against hydrogen peroxide-mediated injury in cells derived from patients with FRDA. Here we extend these studies and have performed a series of experiments showing that expression of superoxide dismutase (1 and 2) enzymes is reduced in FRDA cells but can be restored by treatment with conditioned medium from human MSCs. Furthermore, we have demonstrated that exposure to factors secreted by MSCs increases resistance to nitric oxide-induced oxidative stress in FRDA fibroblasts through, at least in part, restoring the expression of the superoxide dismuting enzymes and via modulation of PI(3) kinase/Akt pathways. These findings suggest that MSCs secrete factors that improve the cellular homeostasis of cells derived from FRDA patients and provide suitable support for their enhanced survival. This study further suggests the potential therapeutic use of MSCs in patients with FRDA.
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Affiliation(s)
- Rimi Dey
- Multiple Sclerosis and Stem Cell Group, Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Bristol, UK
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Lefevre S, Brossas C, Auchère F, Boggetto N, Camadro JM, Santos R. Apn1 AP-endonuclease is essential for the repair of oxidatively damaged DNA bases in yeast frataxin-deficient cells. Hum Mol Genet 2012; 21:4060-72. [PMID: 22706278 PMCID: PMC3428155 DOI: 10.1093/hmg/dds230] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 06/09/2012] [Indexed: 01/16/2023] Open
Abstract
Frataxin deficiency results in mitochondrial dysfunction and oxidative stress and it is the cause of the hereditary neurodegenerative disease Friedreich ataxia (FA). Here, we present evidence that one of the pleiotropic effects of oxidative stress in frataxin-deficient yeast cells (Δyfh1 mutant) is damage to nuclear DNA and that repair requires the Apn1 AP-endonuclease of the base excision repair pathway. Major phenotypes of Δyfh1 cells are respiratory deficit, disturbed iron homeostasis and sensitivity to oxidants. These phenotypes are weak or absent under anaerobiosis. We show here that exposure of anaerobically grown Δyfh1 cells to oxygen leads to down-regulation of antioxidant defenses, increase in reactive oxygen species, delay in G1- and S-phases of the cell cycle and damage to mitochondrial and nuclear DNA. Nuclear DNA lesions in Δyfh1 cells are primarily caused by oxidized bases and single-strand breaks that can be detected 15-30 min after oxygen exposition. The Apn1 enzyme is essential for the repair of the DNA lesions in Δyfh1 cells. Compared with Δyfh1, the double Δyfh1Δapn1 mutant shows growth impairment, increased mutagenesis and extreme sensitivity to H(2)O(2). On the contrary, overexpression of the APN1 gene in Δyfh1 cells decreases spontaneous and induced mutagenesis. Our results show that frataxin deficiency in yeast cells leads to increased DNA base oxidation and requirement of Apn1 for repair, suggesting that DNA damage and repair could be important features in FA disease progression.
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Affiliation(s)
- Sophie Lefevre
- Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
- ED515 UPMC, 4 place Jussieu, 75005 Paris, France and
| | - Caroline Brossas
- Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
| | - Françoise Auchère
- Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
| | - Nicole Boggetto
- ImagoSeine Bioimaging Core Facility, Institut Jacques Monod, 15 rue Hélène Brion, 75205 Paris cedex 13, France
| | - Jean-Michel Camadro
- Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
| | - Renata Santos
- Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France
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Sutak R, Seguin A, Garcia-Serres R, Oddou JL, Dancis A, Tachezy J, Latour JM, Camadro JM, Lesuisse E. Human mitochondrial ferritin improves respiratory function in yeast mutants deficient in iron-sulfur cluster biogenesis, but is not a functional homologue of yeast frataxin. Microbiologyopen 2012; 1:95-104. [PMID: 22950017 PMCID: PMC3426411 DOI: 10.1002/mbo3.18] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/31/2012] [Accepted: 02/06/2012] [Indexed: 12/25/2022] Open
Abstract
We overexpressed human mitochondrial ferritin in frataxin-deficient yeast cells (Δyfh1), but also in another mutant affected in [Fe-S] assembly (Δggc1). Ferritin was correctly processed and expressed in the mitochondria of these cells, but the fraction of total mitochondrial iron bound to ferritin was very low, and most of the iron remained in the form of insoluble particles of ferric phosphate in these mitochondria, as evidenced by gel filtration analysis of the mitochondrial matrix (fast protein liquid chromatography [FPLC]) and by Mössbauer spectroscopy. Mutant cells in which ferritin was overexpressed still accumulated iron in the mitochondria and remained deficient in [Fe-S] assembly, suggesting that human mitochondrial ferritin is not a functional homologue of yeast frataxin. However, the respiratory function was improved in these mutants, which correlates with an improvement of cytochrome and heme synthesis. Overexpression of mitochondrial ferritin in [Fe-S] mutants resulted in the appearance of a small pool of high-spin ferrous iron in the mitochondria, which was probably responsible for the improvement of heme synthesis and of the respiratory function in these mutants.
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Affiliation(s)
- Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University in PragueVinicna 7, 128 44 Prague, Czech Republic
| | - Alexandra Seguin
- Laboratoire Mitochondries, Métaux et Stress oxydant, Institut Jacques Monod, CNRS-Université Paris DiderotFrance
| | - Ricardo Garcia-Serres
- CEA, iRTSV, LCBM, 38054 Grenoble Cedex 9, France; CNRS, UMR5249, Grenoble, France, Université Joseph Fourier38054 Grenoble Cedex 9, France
| | - Jean-Louis Oddou
- CEA, iRTSV, LCBM, 38054 Grenoble Cedex 9, France; CNRS, UMR5249, Grenoble, France, Université Joseph Fourier38054 Grenoble Cedex 9, France
| | - Andrew Dancis
- University of Pennsylvania,, Department of Medicine, Division of Hematology/OncologyBRBII Room 731, 431 Curie Blvd, Philadelphia, PA 19104
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University in PragueVinicna 7, 128 44 Prague, Czech Republic
| | - Jean-Marc Latour
- CEA, iRTSV, LCBM, 38054 Grenoble Cedex 9, France; CNRS, UMR5249, Grenoble, France, Université Joseph Fourier38054 Grenoble Cedex 9, France
| | - Jean-Michel Camadro
- Laboratoire Mitochondries, Métaux et Stress oxydant, Institut Jacques Monod, CNRS-Université Paris DiderotFrance
| | - Emmanuel Lesuisse
- Laboratoire Mitochondries, Métaux et Stress oxydant, Institut Jacques Monod, CNRS-Université Paris DiderotFrance
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