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Abstract
Friedreich's ataxia (FRDA) is a degenerative disease that affects both the central and the peripheral nervous systems and non-neural tissues including, mainly, heart, and endocrine pancreas. It is an autosomal recessive disease caused by a GAA triplet-repeat localized within an Alu sequence element in intron 1 of frataxin (FXN) gene, which encodes a mitochondrial protein FXN. This protein is essential for mitochondrial function by the involvement of iron-sulfur cluster biogenesis. The effects of its deficiency also include disruption of cellular, particularly mitochondrial, iron homeostasis, i.e., relatively more iron accumulated in mitochondria and less iron presented in cytosol. Though iron toxicity is commonly thought to be mediated via Fenton reaction, oxidative stress seems not to be the main problem to result in detrimental effects on cell survival, particularly neuron survival. Therefore, the basic research on FXN function is urgently demanded to understand the disease. This chapter focuses on the outcome of FXN expression, regulation, and function in cellular or animal models of FRDA and on iron pathophysiology in the affected tissues. Finally, therapeutic strategies based on the control of iron toxicity and iron cellular redistribution are considered. The combination of multiple therapeutic targets including iron, oxidative stress, mitochondrial function, and FXN regulation is also proposed.
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Affiliation(s)
- Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, People's Republic of China.
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Garcia-Serres R, Clémancey M, Latour JM, Blondin G. Contribution of Mössbauer spectroscopy to the investigation of Fe/S biogenesis. J Biol Inorg Chem 2018; 23:635-644. [PMID: 29350298 PMCID: PMC6006220 DOI: 10.1007/s00775-018-1534-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/04/2018] [Indexed: 10/27/2022]
Abstract
Fe/S cluster biogenesis involves a complex machinery comprising several mitochondrial and cytosolic proteins. Fe/S cluster biosynthesis is closely intertwined with iron trafficking in the cell. Defects in Fe/S cluster elaboration result in severe diseases such as Friedreich ataxia. Deciphering this machinery is a challenge for the scientific community. Because iron is a key player, 57Fe-Mössbauer spectroscopy is especially appropriate for the characterization of Fe species and monitoring the iron distribution. This minireview intends to illustrate how Mössbauer spectroscopy contributes to unravel steps in Fe/S cluster biogenesis. Studies were performed on isolated proteins that may be present in multiple protein complexes. Since a few decades, Mössbauer spectroscopy was also performed on whole cells or on isolated compartments such as mitochondria and vacuoles, affording an overview of the iron trafficking. This minireview aims at presenting selected applications of 57Fe-Mössbauer spectroscopy to Fe/S cluster biogenesis.
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Affiliation(s)
| | - Martin Clémancey
- Univ. Grenoble Alpes, CEA, CNRS, LCBM UMR 5249, pmb, 38000, Grenoble, France
| | - Jean-Marc Latour
- Univ. Grenoble Alpes, CEA, CNRS, LCBM UMR 5249, pmb, 38000, Grenoble, France
| | - Geneviève Blondin
- Univ. Grenoble Alpes, CEA, CNRS, LCBM UMR 5249, pmb, 38000, Grenoble, France. .,LCBM/pmb, CEA Bât C5, 17 Rue des Martyrs, 38054, Grenoble Cedex 9, France.
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de Llanos R, Martínez-Garay CA, Fita-Torró J, Romero AM, Martínez-Pastor MT, Puig S. Soybean Ferritin Expression in Saccharomyces cerevisiae Modulates Iron Accumulation and Resistance to Elevated Iron Concentrations. Appl Environ Microbiol 2016; 82:3052-3060. [PMID: 26969708 PMCID: PMC4959083 DOI: 10.1128/aem.00305-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/08/2016] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Fungi, including the yeast Saccharomyces cerevisiae, lack ferritin and use vacuoles as iron storage organelles. This work explored how plant ferritin expression influenced baker's yeast iron metabolism. Soybean seed ferritin H1 (SFerH1) and SFerH2 genes were cloned and expressed in yeast cells. Both soybean ferritins assembled as multimeric complexes, which bound yeast intracellular iron in vivo and, consequently, induced the activation of the genes expressed during iron scarcity. Soybean ferritin protected yeast cells that lacked the Ccc1 vacuolar iron detoxification transporter from toxic iron levels by reducing cellular oxidation, thus allowing growth at high iron concentrations. Interestingly, when simultaneously expressed in ccc1Δ cells, SFerH1 and SFerH2 assembled as heteropolymers, which further increased iron resistance and reduced the oxidative stress produced by excess iron compared to ferritin homopolymer complexes. Finally, soybean ferritin expression led to increased iron accumulation in both wild-type and ccc1Δ yeast cells at certain environmental iron concentrations. IMPORTANCE Iron deficiency is a worldwide nutritional disorder to which women and children are especially vulnerable. A common strategy to combat iron deficiency consists of dietary supplementation with inorganic iron salts, whose bioavailability is very low. Iron-enriched yeasts and cereals are alternative strategies to diminish iron deficiency. Animals and plants possess large ferritin complexes that accumulate, detoxify, or buffer excess cellular iron. However, the yeast Saccharomyces cerevisiae lacks ferritin and uses vacuoles as iron storage organelles. Here, we explored how soybean ferritin expression influenced yeast iron metabolism, confirming that yeasts that express soybean seed ferritin could be explored as a novel strategy to increase dietary iron absorption.
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Affiliation(s)
- Rosa de Llanos
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Paterna, Valencia, Spain
| | - Carlos Andrés Martínez-Garay
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Paterna, Valencia, Spain
| | - Josep Fita-Torró
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Paterna, Valencia, Spain
| | - Antonia María Romero
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Paterna, Valencia, Spain
| | | | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Paterna, Valencia, Spain
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Martelli A, Puccio H. Dysregulation of cellular iron metabolism in Friedreich ataxia: from primary iron-sulfur cluster deficit to mitochondrial iron accumulation. Front Pharmacol 2014; 5:130. [PMID: 24917819 PMCID: PMC4042101 DOI: 10.3389/fphar.2014.00130] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 05/14/2014] [Indexed: 01/25/2023] Open
Abstract
Friedreich ataxia (FRDA) is the most common recessive ataxia in the Caucasian population and is characterized by a mixed spinocerebellar and sensory ataxia frequently associating cardiomyopathy. The disease results from decreased expression of the FXN gene coding for the mitochondrial protein frataxin. Early histological and biochemical study of the pathophysiology in patient's samples revealed that dysregulation of iron metabolism is a key feature of the disease, mainly characterized by mitochondrial iron accumulation and by decreased activity of iron-sulfur cluster enzymes. In the recent past years, considerable progress in understanding the function of frataxin has been provided through cellular and biochemical approaches, pointing to the primary role of frataxin in iron-sulfur cluster biogenesis. However, why and how the impact of frataxin deficiency on this essential biosynthetic pathway leads to mitochondrial iron accumulation is still poorly understood. Herein, we review data on both the primary function of frataxin and the nature of the iron metabolism dysregulation in FRDA. To date, the pathophysiological implication of the mitochondrial iron overload in FRDA remains to be clarified.
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Affiliation(s)
- Alain Martelli
- Department of Translational Medecine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch, France ; INSERM, U596 Illkirch, France ; CNRS, UMR7104 Illkirch, France ; Université de Strasbourg Strasbourg, France ; Chaire de Génétique Humaine, Collège de France Illkirch, France
| | - Hélène Puccio
- Department of Translational Medecine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch, France ; INSERM, U596 Illkirch, France ; CNRS, UMR7104 Illkirch, France ; Université de Strasbourg Strasbourg, France ; Chaire de Génétique Humaine, Collège de France Illkirch, France
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Vigani G, Tarantino D, Murgia I. Mitochondrial ferritin is a functional iron-storage protein in cucumber (Cucumis sativus) roots. FRONTIERS IN PLANT SCIENCE 2013; 4:316. [PMID: 23967005 PMCID: PMC3744851 DOI: 10.3389/fpls.2013.00316] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/28/2013] [Indexed: 05/23/2023]
Abstract
In plants, intracellular Fe trafficking must satisfy chloroplasts' and mitochondrial demands for Fe without allowing its accumulation in the organelles in dangerous redox-active forms. Protein ferritin is involved in such homeostatic control, however its functional role in mitochondria, differently from its role in chloroplasts, is still matter of debate. To test ferritin functionality as a 24-mer Fe-storage complex in mitochondria, cucumber seedlings were grown under different conditions of Fe supply (excess, control, deficiency) and mitochondria were purified from the roots. A ferritin monomer of around 25 KDa was detected by SDS-PAGE in Fe-excess root mitochondria, corresponding to the annotated Csa5M215130/XP_004163524 protein: such a monomer is barely detectable in the control mitochondria and not at all in the Fe-deficient ones. Correspondingly, the ferritin 24-mer complex is abundant in root mitochondria from Fe-excess plants and it stores Fe as Fe(III): such a complex is also detectable, though to a much smaller extent, in control mitochondria, but not in Fe-deficient ones. Cucumber ferritin Csa5M215130/XP_004163524 is therefore a functional Fe(III)-store in root mitochondria and its abundance is dependent on the Fe nutritional status of the plant.
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Affiliation(s)
- Gianpiero Vigani
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
| | - Delia Tarantino
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilano, Italy
| | - Irene Murgia
- Dipartimento di Bioscienze, Università degli Studi di MilanoMilano, Italy
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Couturier J, Touraine B, Briat JF, Gaymard F, Rouhier N. The iron-sulfur cluster assembly machineries in plants: current knowledge and open questions. FRONTIERS IN PLANT SCIENCE 2013; 4:259. [PMID: 23898337 PMCID: PMC3721309 DOI: 10.3389/fpls.2013.00259] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/25/2013] [Indexed: 05/18/2023]
Abstract
Many metabolic pathways and cellular processes occurring in most sub-cellular compartments depend on the functioning of iron-sulfur (Fe-S) proteins, whose cofactors are assembled through dedicated protein machineries. Recent advances have been made in the knowledge of the functions of individual components through a combination of genetic, biochemical and structural approaches, primarily in prokaryotes and non-plant eukaryotes. Whereas most of the components of these machineries are conserved between kingdoms, their complexity is likely increased in plants owing to the presence of additional assembly proteins and to the existence of expanded families for several assembly proteins. This review focuses on the new actors discovered in the past few years, such as glutaredoxin, BOLA and NEET proteins as well as MIP18, MMS19, TAH18, DRE2 for the cytosolic machinery, which are integrated into a model for the plant Fe-S cluster biogenesis systems. It also discusses a few issues currently subjected to an intense debate such as the role of the mitochondrial frataxin and of glutaredoxins, the functional separation between scaffold, carrier and iron-delivery proteins and the crosstalk existing between different organelles.
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Affiliation(s)
- Jérémy Couturier
- Interactions Arbres/Micro-organismes, Faculté des Sciences, UMR1136 Université de Lorraine-INRAVandoeuvre, France
| | - Brigitte Touraine
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-INRA-Université Montpellier 2Montpellier, France
| | - Jean-François Briat
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-INRA-Université Montpellier 2Montpellier, France
| | - Frédéric Gaymard
- Biochimie et Physiologie Moléculaire des Plantes, Centre National de la Recherche Scientifique-INRA-Université Montpellier 2Montpellier, France
| | - Nicolas Rouhier
- Interactions Arbres/Micro-organismes, Faculté des Sciences, UMR1136 Université de Lorraine-INRAVandoeuvre, France
- *Correspondence: Nicolas Rouhier, Université de Lorraine, UMR1136 Université de Lorraine-INRA, Interactions Arbres/Micro-organismes, Faculté des Sciences, Bd des aiguillettes, BP 239,54506 Vandoeuvre, France e-mail:
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