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Da Conceição LMA, Cabral LM, Pereira GRC, De Mesquita JF. An In Silico Analysis of Genetic Variants and Structural Modeling of the Human Frataxin Protein in Friedreich's Ataxia. Int J Mol Sci 2024; 25:5796. [PMID: 38891993 PMCID: PMC11172458 DOI: 10.3390/ijms25115796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
Friedreich's Ataxia (FRDA) stands out as the most prevalent form of hereditary ataxias, marked by progressive movement ataxia, loss of vibratory sensitivity, and skeletal deformities, severely affecting daily functioning. To date, the only medication available for treating FRDA is Omaveloxolone (Skyclarys®), recently approved by the FDA. Missense mutations within the human frataxin (FXN) gene, responsible for intracellular iron homeostasis regulation, are linked to FRDA development. These mutations induce FXN dysfunction, fostering mitochondrial iron accumulation and heightened oxidative stress, ultimately triggering neuronal cell death pathways. This study amalgamated 226 FXN genetic variants from the literature and database searches, with only 18 previously characterized. Predictive analyses revealed a notable prevalence of detrimental and destabilizing predictions for FXN mutations, predominantly impacting conserved residues crucial for protein function. Additionally, an accurate, comprehensive three-dimensional model of human FXN was constructed, serving as the basis for generating genetic variants I154F and W155R. These variants, selected for their severe clinical implications, underwent molecular dynamics (MD) simulations, unveiling flexibility and essential dynamic alterations in their N-terminal segments, encompassing FXN42, FXN56, and FXN78 domains pivotal for protein maturation. Thus, our findings indicate potential interaction profile disturbances in the FXN42, FXN56, and FXN78 domains induced by I154F and W155R mutations, aligning with the existing literature.
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Affiliation(s)
- Loiane Mendonça Abrantes Da Conceição
- Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro (UNIRIO), Avenida Pasteur, 296, Urca, Rio de Janeiro 22290-250, Brazil (J.F.D.M.)
| | - Lucio Mendes Cabral
- Pharmaceutical Industrial Technology Laboratory, Federal University of Rio de Janeiro (UFRJ), Avenida Carlos Chagas Filho, 373, Cidade Universitária, Rio de Janeiro 21941-590, Brazil
| | - Gabriel Rodrigues Coutinho Pereira
- Pharmaceutical Industrial Technology Laboratory, Federal University of Rio de Janeiro (UFRJ), Avenida Carlos Chagas Filho, 373, Cidade Universitária, Rio de Janeiro 21941-590, Brazil
- Laboratory of Molecular Modeling & QSAR, Federal University of Rio de Janeiro (UFRJ), Avenida Carlos Chagas Filho, 373, Cidade Universitária, Rio de Janeiro 21941-590, Brazil
| | - Joelma Freire De Mesquita
- Laboratory of Bioinformatics and Computational Biology, Federal University of the State of Rio de Janeiro (UNIRIO), Avenida Pasteur, 296, Urca, Rio de Janeiro 22290-250, Brazil (J.F.D.M.)
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Bernardo-Seisdedos G, Schedlbauer A, Pereira-Ortuzar T, Mato JM, Millet O. Protoporphyrin IX Binds to Iron(II)-Loaded and to Zinc-Loaded Human Frataxin. LIFE (BASEL, SWITZERLAND) 2023; 13:life13010222. [PMID: 36676171 PMCID: PMC9866752 DOI: 10.3390/life13010222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/14/2023]
Abstract
(1) Background: Human frataxin is an iron binding protein that participates in the biogenesis of iron sulfur clusters and enhances ferrochelatase activity. While frataxin association to other proteins has been extensively characterized up to the structural level, much less is known about the putative capacity of frataxin to interact with functionally related metabolites. In turn, current knowledge about frataxin's capacity to coordinate metal ions is limited to iron (II and III); (2) Methods: here, we used NMR spectroscopy, Molecular Dynamics, and Docking approaches to demonstrate new roles of frataxin; (3) Results: We demonstrate that frataxin also binds Zn2+ in a structurally similar way to Fe2+, but with lower affinity. In turn, both Fe2+-loaded and Zn2+-loaded frataxins specifically associate to protoporphyrin IX with micromolar affinity, while apo-frataxin does not bind to the porphyrin. Protoporphyrin IX association to metal-loaded frataxin shares the binding epitope with ferrochelatase; and (4) Conclusions: these findings expand the plethora of relevant molecular targets for frataxin and may help to elucidate the yet unknown different roles that this protein exerts in iron regulation and metabolism.
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Affiliation(s)
- Ganeko Bernardo-Seisdedos
- ATLAS Molecular Pharma, Bizkaia Science and Technology Park, 48160 Derio, Spain
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160 Derio, Spain
| | - Andreas Schedlbauer
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160 Derio, Spain
| | - Tania Pereira-Ortuzar
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160 Derio, Spain
| | - José M. Mato
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160 Derio, Spain
- Biomedical Research Network on Hepatic and Digestive Diseases (CIBEREHD), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Oscar Millet
- ATLAS Molecular Pharma, Bizkaia Science and Technology Park, 48160 Derio, Spain
- Precision Medicine and Metabolism Laboratory, CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park, 48160 Derio, Spain
- Biomedical Research Network on Hepatic and Digestive Diseases (CIBEREHD), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence:
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Wang D, Ho ES, Cotticelli MG, Xu P, Napierala JS, Hauser LA, Napierala M, Himes BE, Wilson RB, Lynch DR, Mesaros C. Skin fibroblast metabolomic profiling reveals that lipid dysfunction predicts the severity of Friedreich's ataxia. J Lipid Res 2022; 63:100255. [PMID: 35850241 PMCID: PMC9399481 DOI: 10.1016/j.jlr.2022.100255] [Citation(s) in RCA: 5] [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: 11/27/2021] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 12/26/2022] Open
Abstract
Friedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by a triplet guanine-adenine-adenine (GAA) repeat expansion in intron 1 of the FXN gene, which leads to decreased levels of the frataxin protein. Frataxin is involved in the formation of iron-sulfur (Fe-S) cluster prosthetic groups for various metabolic enzymes. To provide a better understanding of the metabolic status of patients with FRDA, here we used patient-derived fibroblast cells as a surrogate tissue for metabolic and lipidomic profiling by liquid chromatography-high resolution mass spectrometry. We found elevated HMG-CoA and β-hydroxybutyrate-CoA levels, implying dysregulated fatty acid oxidation, which was further demonstrated by elevated acyl-carnitine levels. Lipidomic profiling identified dysregulated levels of several lipid classes in FRDA fibroblast cells when compared with non-FRDA fibroblast cells. For example, levels of several ceramides were significantly increased in FRDA fibroblast cells; these results positively correlated with the GAA repeat length and negatively correlated with the frataxin protein levels. Furthermore, stable isotope tracing experiments indicated increased ceramide synthesis, especially for long-chain fatty acid-ceramides, in FRDA fibroblast cells compared with ceramide synthesis in healthy control fibroblast cells. In addition, PUFA-containing triglycerides and phosphatidylglycerols were enriched in FRDA fibroblast cells and negatively correlated with frataxin levels, suggesting lipid remodeling as a result of FXN deficiency. Altogether, we demonstrate patient-derived fibroblast cells exhibited dysregulated metabolic capabilities, and their lipid dysfunction predicted the severity of FRDA, making them a useful surrogate to study the metabolic status in FRDA.
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Affiliation(s)
- Dezhen Wang
- Center for Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elaine S Ho
- Center for Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - M Grazia Cotticelli
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Peining Xu
- Center for Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jill S Napierala
- University of Alabama at Birmingham, Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, Birmingham, Alabama, USA
| | - Lauren A Hauser
- Department of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research, Philadelphia, Pennsylvania, USA
| | - Marek Napierala
- University of Alabama at Birmingham, Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, Birmingham, Alabama, USA
| | - Blanca E Himes
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert B Wilson
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - David R Lynch
- Department of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research, Philadelphia, Pennsylvania, USA
| | - Clementina Mesaros
- Center for Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Terenzi A, Pagani MA, Gomez-Casati DF, Busi MV. Structural and Functional Characterization of CreFH1, the Frataxin Homolog from Chlamydomonas reinhardtii. PLANTS 2022; 11:plants11151931. [PMID: 35893635 PMCID: PMC9331050 DOI: 10.3390/plants11151931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/14/2022] [Accepted: 07/19/2022] [Indexed: 11/29/2022]
Abstract
Frataxin plays a key role in cellular iron homeostasis of different organisms. It has been implicated in iron storage, detoxification, delivery for Fe-S cluster assembly and heme biosynthesis. However, its specific role in iron metabolism remains unclear, especially in photosynthetic organisms. To gain insight into the role and properties of frataxin in algae, we identified the gene CreFH1, which codes for the frataxin homolog from Chlamydomonas reinhardtii. We performed the cloning, expression and biochemical characterization of CreFH1. This protein has a predicted mitochondrial transit peptide and a significant structural similarity to other members of the frataxin family. In addition, CreFH1 was able to form a dimer in vitro, and this effect was increased by the addition of Cu2+ and also attenuated the Fenton reaction in the presence of a mixture of Fe2+ and H2O2. Bacterial cells with overexpression of CreFH1 showed increased growth in the presence of different metals, such as Fe, Cu, Zn and Ni and H2O2. Thus, results indicated that CreFH1 is a functional protein that shows some distinctive features compared to its more well-known counterparts, and would play an important role in response to oxidative stress in C. reinhardtii.
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Monfort B, Want K, Gervason S, D’Autréaux B. Recent Advances in the Elucidation of Frataxin Biochemical Function Open Novel Perspectives for the Treatment of Friedreich’s Ataxia. Front Neurosci 2022; 16:838335. [PMID: 35310092 PMCID: PMC8924461 DOI: 10.3389/fnins.2022.838335] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/28/2022] [Indexed: 12/25/2022] Open
Abstract
Friedreich’s ataxia (FRDA) is the most prevalent autosomic recessive ataxia and is associated with a severe cardiac hypertrophy and less frequently diabetes. It is caused by mutations in the gene encoding frataxin (FXN), a small mitochondrial protein. The primary consequence is a defective expression of FXN, with basal protein levels decreased by 70–98%, which foremost affects the cerebellum, dorsal root ganglia, heart and liver. FXN is a mitochondrial protein involved in iron metabolism but its exact function has remained elusive and highly debated since its discovery. At the cellular level, FRDA is characterized by a general deficit in the biosynthesis of iron-sulfur (Fe-S) clusters and heme, iron accumulation and deposition in mitochondria, and sensitivity to oxidative stress. Based on these phenotypes and the proposed ability of FXN to bind iron, a role as an iron storage protein providing iron for Fe-S cluster and heme biosynthesis was initially proposed. However, this model was challenged by several other studies and it is now widely accepted that FXN functions primarily in Fe-S cluster biosynthesis, with iron accumulation, heme deficiency and oxidative stress sensitivity appearing later on as secondary defects. Nonetheless, the biochemical function of FXN in Fe-S cluster biosynthesis is still debated. Several roles have been proposed for FXN: iron chaperone, gate-keeper of detrimental Fe-S cluster biosynthesis, sulfide production stimulator and sulfur transfer accelerator. A picture is now emerging which points toward a unique function of FXN as an accelerator of a key step of sulfur transfer between two components of the Fe-S cluster biosynthetic complex. These findings should foster the development of new strategies for the treatment of FRDA. We will review here the latest discoveries on the biochemical function of frataxin and the implication for a potential therapeutic treatment of FRDA.
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Doni D, Rigoni G, Palumbo E, Baschiera E, Peruzzo R, De Rosa E, Caicci F, Passerini L, Bettio D, Russo A, Szabò I, Soriano ME, Salviati L, Costantini P. The displacement of frataxin from the mitochondrial cristae correlates with abnormal respiratory supercomplexes formation and bioenergetic defects in cells of Friedreich ataxia patients. FASEB J 2021; 35:e21362. [PMID: 33629768 DOI: 10.1096/fj.202000524rr] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 12/09/2020] [Accepted: 12/28/2020] [Indexed: 12/23/2022]
Abstract
Friedreich ataxia (FRDA) is a neurodegenerative disease resulting from a severe decrease of frataxin (FXN). Most patients carry a GAA repeat expansion in both alleles of the FXN gene, whereas a small fraction of them are compound heterozygous for the expansion and a point mutation in the other allele. FXN is involved in the mitochondrial biogenesis of the FeS-clusters. Distinctive feature of FRDA patient cells is an impaired cellular respiration, likely due to a deficit of key redox cofactors working as electrons shuttles through the respiratory chain. However, a definite relationship between FXN levels, FeS-clusters assembly dysregulation and bioenergetics failure has not been established. In this work, we performed a comparative analysis of the mitochondrial phenotype of cell lines from FRDA patients, either homozygous for the expansion or compound heterozygotes for the G130V mutation. We found that, in healthy cells, FXN and two key proteins of the FeS-cluster assembly machinery are enriched in mitochondrial cristae, the dynamic subcompartment housing the respiratory chain. On the contrary, FXN widely redistributes to the matrix in FRDA cells with defects in respiratory supercomplexes assembly and altered respiratory function. We propose that this could be relevant for the early mitochondrial defects afflicting FRDA cells and that perturbation of mitochondrial morphodynamics could in turn be critical in terms of disease mechanisms.
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Affiliation(s)
- Davide Doni
- Department of Biology, University of Padova, Padova, Italy
| | | | - Elisa Palumbo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Elisa Baschiera
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
- Istituto di Ricerca Pediatrica (IRP) Città della Speranza, Padova, Italy
| | | | - Edith De Rosa
- Department of Biology, University of Padova, Padova, Italy
| | | | | | - Daniela Bettio
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
- Istituto di Ricerca Pediatrica (IRP) Città della Speranza, Padova, Italy
| | - Antonella Russo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Ildiko Szabò
- Department of Biology, University of Padova, Padova, Italy
| | | | - Leonardo Salviati
- Clinical Genetics Unit, Department of Women's and Children's Health, University of Padova, Padova, Italy
- Istituto di Ricerca Pediatrica (IRP) Città della Speranza, Padova, Italy
- Myology Center, University of Padova, Padova, Italy
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Gladyck S, Aras S, Hüttemann M, Grossman LI. Regulation of COX Assembly and Function by Twin CX 9C Proteins-Implications for Human Disease. Cells 2021; 10:197. [PMID: 33498264 PMCID: PMC7909247 DOI: 10.3390/cells10020197] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/29/2022] Open
Abstract
Oxidative phosphorylation is a tightly regulated process in mammals that takes place in and across the inner mitochondrial membrane and consists of the electron transport chain and ATP synthase. Complex IV, or cytochrome c oxidase (COX), is the terminal enzyme of the electron transport chain, responsible for accepting electrons from cytochrome c, pumping protons to contribute to the gradient utilized by ATP synthase to produce ATP, and reducing oxygen to water. As such, COX is tightly regulated through numerous mechanisms including protein-protein interactions. The twin CX9C family of proteins has recently been shown to be involved in COX regulation by assisting with complex assembly, biogenesis, and activity. The twin CX9C motif allows for the import of these proteins into the intermembrane space of the mitochondria using the redox import machinery of Mia40/CHCHD4. Studies have shown that knockdown of the proteins discussed in this review results in decreased or completely deficient aerobic respiration in experimental models ranging from yeast to human cells, as the proteins are conserved across species. This article highlights and discusses the importance of COX regulation by twin CX9C proteins in the mitochondria via COX assembly and control of its activity through protein-protein interactions, which is further modulated by cell signaling pathways. Interestingly, select members of the CX9C protein family, including MNRR1 and CHCHD10, show a novel feature in that they not only localize to the mitochondria but also to the nucleus, where they mediate oxygen- and stress-induced transcriptional regulation, opening a new view of mitochondrial-nuclear crosstalk and its involvement in human disease.
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Affiliation(s)
- Stephanie Gladyck
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.G.); (S.A.); (M.H.)
| | - Siddhesh Aras
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.G.); (S.A.); (M.H.)
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland and Detroit, MI 48201, USA
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.G.); (S.A.); (M.H.)
| | - Lawrence I. Grossman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.G.); (S.A.); (M.H.)
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland and Detroit, MI 48201, USA
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Gao J, Zhou Q, Wu D, Chen L. Mitochondrial iron metabolism and its role in diseases. Clin Chim Acta 2020; 513:6-12. [PMID: 33309797 DOI: 10.1016/j.cca.2020.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 12/25/2022]
Abstract
Iron is one of the most important elements for life, but excess iron is toxic. Intracellularly, mitochondria are the center of iron utilization requiring sufficient amounts to maintain normal physiologic function. Accordingly, disruption of iron homeostasis could seriously impact mitochondrial function leading to impaired energy state and potential disease development. In this review, we discuss mechanisms of iron metabolism including transport, processing, heme synthesis, iron-sulfur cluster biogenesis and storage. We highlight the vital role of mitochondrial iron in pathologic states including neurodegenerative disorders and sideroblastic anemia.
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Affiliation(s)
- Jiayin Gao
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Qionglin Zhou
- Department of Pharmacy, The First People's Hospital of Shaoguan, Shaoguan Hospital of Southern Medical University, Shaoguan 512000, China
| | - Di Wu
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China.
| | - Linxi Chen
- Institute of Pharmacy and Pharmacology, Learning Key Laboratory for Pharmacoproteomics, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China.
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Rodríguez LR, Calap-Quintana P, Lapeña-Luzón T, Pallardó FV, Schneuwly S, Navarro JA, Gonzalez-Cabo P. Oxidative stress modulates rearrangement of endoplasmic reticulum-mitochondria contacts and calcium dysregulation in a Friedreich's ataxia model. Redox Biol 2020; 37:101762. [PMID: 33128998 PMCID: PMC7585950 DOI: 10.1016/j.redox.2020.101762] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 10/07/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Friedreich ataxia (FRDA) is a neurodegenerative disorder characterized by neuromuscular and neurological manifestations. It is caused by mutations in the FXN gene, which results in loss of the mitochondrial protein frataxin. Endoplasmic Reticulum-mitochondria associated membranes (MAMs) are inter-organelle structures involved in the regulation of essential cellular processes, including lipid metabolism and calcium signaling. In the present study, we have analyzed in both, unicellular and multicellular models of FRDA, calcium management and integrity of MAMs. We observed that function of MAMs is compromised in our cellular model of FRDA, which was improved upon treatment with antioxidants. In agreement, promoting mitochondrial calcium uptake was sufficient to restore several defects caused by frataxin deficiency in Drosophila Melanogaster. Remarkably, our findings describe for the first time frataxin as a member of the protein network of MAMs, where interacts with two of the main proteins implicated in endoplasmic reticulum-mitochondria communication. These results suggest a new role of frataxin, indicate that FRDA goes beyond mitochondrial defects and highlight MAMs as novel therapeutic candidates to improve patient's conditions.
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Affiliation(s)
- Laura R Rodríguez
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain; Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain
| | - Pablo Calap-Quintana
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain; Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain; CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Tamara Lapeña-Luzón
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain; Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain; CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Federico V Pallardó
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain; Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain; CIBER de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Stephan Schneuwly
- Institute of Zoology, Universitaetsstrasse 31, University of Regensburg, 93040, Regensburg, Germany
| | - Juan A Navarro
- Institute of Zoology, Universitaetsstrasse 31, University of Regensburg, 93040, Regensburg, Germany; INCLIVA Biomedial Research Institute, Valencia, Spain
| | - Pilar Gonzalez-Cabo
- Department of Physiology, Faculty of Medicine and Dentistry. University of Valencia-INCLIVA, Valencia, 46010, Spain; Associated Unit for Rare Diseases INCLIVA-CIPF, Valencia, Spain; CIBER de Enfermedades Raras (CIBERER), Valencia, Spain.
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Misiorek JO, Schreiber AM, Urbanek-Trzeciak MO, Jazurek-Ciesiołka M, Hauser LA, Lynch DR, Napierala JS, Napierala M. A Comprehensive Transcriptome Analysis Identifies FXN and BDNF as Novel Targets of miRNAs in Friedreich's Ataxia Patients. Mol Neurobiol 2020; 57:2639-2653. [PMID: 32291635 PMCID: PMC7253519 DOI: 10.1007/s12035-020-01899-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/09/2020] [Indexed: 12/13/2022]
Abstract
Friedreich's ataxia (FRDA) is a genetic neurodegenerative disease that is caused by guanine-adenine-adenine (GAA) nucleotide repeat expansions in the first intron of the frataxin (FXN) gene. Although present in the intron, this mutation leads to a substantial decrease in protein expression. Currently, no effective treatment is available for FRDA, and, in addition to FXN, other targets with therapeutic potential are continuously sought. As miRNAs can regulate the expression of a broad spectrum of genes, are used as biomarkers, and can serve as therapeutic tools, we decided to identify and characterize differentially expressed miRNAs and their targets in FRDA cells compared to unaffected control (CTRL) cells. In this study, we performed an integrated miRNAseq and RNAseq analysis using the same cohort of primary FRDA and CTRL cells. The results of the transcriptome studies were supported by bioinformatic analyses and validated by qRT-PCR. miRNA interactions with target genes were assessed by luciferase assays, qRT-PCR, and immunoblotting. In silico analysis identified the FXN transcript as a target of five miRNAs upregulated in FRDA cells. Further studies confirmed that miRNA-224-5p indeed targets FXN, resulting in decreases in mRNA and protein levels. We also validated the ability of miRNA-10a-5p to bind and regulate the levels of brain-derived neurotrophic factor (BDNF), an important modulator of neuronal growth. We observed a significant decrease in the levels of miRNA-10a-5p and increase in the levels of BDNF upon correction of FRDA cells via zinc-finger nuclease (ZFN)-mediated excision of expanded GAA repeats. Our comprehensive transcriptome analyses identified miRNA-224-5p and miRNA-10a-5p as negative regulators of the FXN and BDNF expression, respectively. These results emphasize not only the importance of miRNAs in the pathogenesis of FRDA but also their potential as therapeutic targets for this disease.
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Affiliation(s)
- Julia O. Misiorek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Anna M. Schreiber
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, Birmingham, AL USA
| | | | | | - Lauren A. Hauser
- Department of Pediatrics and Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
- Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - David R. Lynch
- Department of Pediatrics and Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA USA
- Children’s Hospital of Philadelphia, Philadelphia, PA USA
| | - Jill S. Napierala
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, Birmingham, AL USA
| | - Marek Napierala
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, Birmingham, AL USA
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Chiabrando D, Bertino F, Tolosano E. Hereditary Ataxia: A Focus on Heme Metabolism and Fe-S Cluster Biogenesis. Int J Mol Sci 2020; 21:ijms21113760. [PMID: 32466579 PMCID: PMC7312568 DOI: 10.3390/ijms21113760] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023] Open
Abstract
Heme and Fe-S clusters regulate a plethora of essential biological processes ranging from cellular respiration and cell metabolism to the maintenance of genome integrity. Mutations in genes involved in heme metabolism and Fe-S cluster biogenesis cause different forms of ataxia, like posterior column ataxia and retinitis pigmentosa (PCARP), Friedreich's ataxia (FRDA) and X-linked sideroblastic anemia with ataxia (XLSA/A). Despite great efforts in the elucidation of the molecular pathogenesis of these disorders several important questions still remain to be addressed. Starting with an overview of the biology of heme metabolism and Fe-S cluster biogenesis, the review discusses recent progress in the understanding of the molecular pathogenesis of PCARP, FRDA and XLSA/A, and highlights future line of research in the field. A better comprehension of the mechanisms leading to the degeneration of neural circuity responsible for balance and coordinated movement will be crucial for the therapeutic management of these patients.
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12
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McMackin MZ, Durbin-Johnson B, Napierala M, Napierala JS, Ruiz L, Napoli E, Perlman S, Giulivi C, Cortopassi GA. Potential biomarker identification for Friedreich's ataxia using overlapping gene expression patterns in patient cells and mouse dorsal root ganglion. PLoS One 2019; 14:e0223209. [PMID: 31665133 PMCID: PMC6821053 DOI: 10.1371/journal.pone.0223209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/15/2019] [Indexed: 12/22/2022] Open
Abstract
Friedreich's ataxia (FA) is a neurodegenerative disease with no approved therapy that is the result of frataxin deficiency. The identification of human FA blood biomarkers related to disease severity and neuro-pathomechanism could support clinical trials of drug efficacy. To try to identify human biomarkers of neuro-pathomechanistic relevance, we compared the overlapping gene expression changes of primary blood and skin cells of FA patients with changes in the Dorsal Root Ganglion (DRG) of the KIKO FA mouse model. As DRG is the primary site of neurodegeneration in FA, our goal was to identify which changes in blood and skin of FA patients provide a 'window' into the FA neuropathomechanism inside the nervous system. In addition, gene expression in frataxin-deficient neuroglial cells and FA mouse hearts were compared for a total of 5 data sets. The overlap of these changes strongly supports mitochondrial changes, apoptosis and alterations of selenium metabolism. Consistent biomarkers were observed, including three genes of mitochondrial stress (MTIF2, ENO2), apoptosis (DDIT3/CHOP), oxidative stress (PREX1), and selenometabolism (SEPW1). These results prompted our investigation of the GPX1 activity as a marker of selenium and oxidative stress, in which we observed a significant change in FA patients. We believe these lead biomarkers that could be assayed in FA patient blood as indicators of disease severity and progression, and also support the involvement of mitochondria, apoptosis and selenium in the neurodegenerative process.
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Affiliation(s)
- Marissa Z. McMackin
- Department of Molecular Biosciences, University of California, Davis, Davis, California, United States of America
| | - Blythe Durbin-Johnson
- Bioinformatics, University of California, Davis, Davis, California, United States of America
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jill S. Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Luis Ruiz
- Department of Molecular Biosciences, University of California, Davis, Davis, California, United States of America
| | - Eleonora Napoli
- Department of Molecular Biosciences, University of California, Davis, Davis, California, United States of America
| | - Susan Perlman
- Department of Neurology, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Cecilia Giulivi
- Department of Molecular Biosciences, University of California, Davis, Davis, California, United States of America
| | - Gino A. Cortopassi
- Department of Molecular Biosciences, University of California, Davis, Davis, California, United States of America
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13
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Llorens JV, Soriano S, Calap-Quintana P, Gonzalez-Cabo P, Moltó MD. The Role of Iron in Friedreich's Ataxia: Insights From Studies in Human Tissues and Cellular and Animal Models. Front Neurosci 2019; 13:75. [PMID: 30833885 PMCID: PMC6387962 DOI: 10.3389/fnins.2019.00075] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/23/2019] [Indexed: 12/12/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a rare early-onset degenerative disease that affects both the central and peripheral nervous systems, and other extraneural tissues, mainly the heart and endocrine pancreas. This disorder progresses as a mixed sensory and cerebellar ataxia, primarily disturbing the proprioceptive pathways in the spinal cord, peripheral nerves and nuclei of the cerebellum. FRDA is an inherited disease with an autosomal recessive pattern caused by an insufficient amount of the nuclear-encoded mitochondrial protein frataxin, which is an essential and highly evolutionary conserved protein whose deficit results in iron metabolism dysregulation and mitochondrial dysfunction. The first experimental evidence connecting frataxin with iron homeostasis came from Saccharomyces cerevisiae; iron accumulates in the mitochondria of yeast with deletion of the frataxin ortholog gene. This finding was soon linked to previous observations of iron deposits in the hearts of FRDA patients and was later reported in animal models of the disease. Despite advances made in the understanding of FRDA pathophysiology, the role of iron in this disease has not yet been completely clarified. Some of the questions still unresolved include the molecular mechanisms responsible for the iron accumulation and iron-mediated toxicity. Here, we review the contribution of the cellular and animal models of FRDA and relevance of the studies using FRDA patient samples to gain knowledge about these issues. Mechanisms of mitochondrial iron overload are discussed considering the potential roles of frataxin in the major mitochondrial metabolic pathways that use iron. We also analyzed the effect of iron toxicity on neuronal degeneration in FRDA by reactive oxygen species (ROS)-dependent and ROS-independent mechanisms. Finally, therapeutic strategies based on the control of iron toxicity are considered.
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Affiliation(s)
- José Vicente Llorens
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Valencia, Spain
- Unit for Psychiatry and Neurodegenerative Diseases, Biomedical Research Institute INCLIVA, Valencia, Spain
| | - Sirena Soriano
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
| | - Pablo Calap-Quintana
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Valencia, Spain
- Unit for Psychiatry and Neurodegenerative Diseases, Biomedical Research Institute INCLIVA, Valencia, Spain
| | - Pilar Gonzalez-Cabo
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
- Center of Biomedical Network Research on Rare Diseases CIBERER, Valencia, Spain
- Associated Unit for Rare Diseases INCLIVA-CIPF, Biomedical Research Institute INCLIVA, Valencia, Spain
| | - María Dolores Moltó
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Valencia, Spain
- Unit for Psychiatry and Neurodegenerative Diseases, Biomedical Research Institute INCLIVA, Valencia, Spain
- Center of Biomedical Network Research on Mental Health CIBERSAM, Valencia, Spain
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14
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Castro IH, Pignataro MF, Sewell KE, Espeche LD, Herrera MG, Noguera ME, Dain L, Nadra AD, Aran M, Smal C, Gallo M, Santos J. Frataxin Structure and Function. Subcell Biochem 2019; 93:393-438. [PMID: 31939159 DOI: 10.1007/978-3-030-28151-9_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mammalian frataxin is a small mitochondrial protein involved in iron sulfur cluster assembly. Frataxin deficiency causes the neurodegenerative disease Friedreich's Ataxia. Valuable knowledge has been gained on the structural dynamics of frataxin, metal-ion-protein interactions, as well as on the effect of mutations on protein conformation, stability and internal motions. Additionally, laborious studies concerning the enzymatic reactions involved have allowed for understanding the capability of frataxin to modulate Fe-S cluster assembly function. Remarkably, frataxin biological function depends on its interaction with some proteins to form a supercomplex, among them NFS1 desulfurase and ISCU, the scaffolding protein. By combining multiple experimental tools including high resolution techniques like NMR and X-ray, but also SAXS, crosslinking and mass-spectrometry, it was possible to build a reliable model of the structure of the desulfurase supercomplex NFS1/ACP-ISD11/ISCU/frataxin. In this chapter, we explore these issues showing how the scientific view concerning frataxin structure-function relationships has evolved over the last years.
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Affiliation(s)
- Ignacio Hugo Castro
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
- Intituto de Química y Fisicoquímica Biológicas, Dr. Alejandro Paladini Universidad de Buenos Aires, CONICET, Junín 956, 1113AAD, C.A.B.A, Argentina
| | - María Florencia Pignataro
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
- Intituto de Química y Fisicoquímica Biológicas, Dr. Alejandro Paladini Universidad de Buenos Aires, CONICET, Junín 956, 1113AAD, C.A.B.A, Argentina
| | - Karl Ellioth Sewell
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
- Intituto de Química y Fisicoquímica Biológicas, Dr. Alejandro Paladini Universidad de Buenos Aires, CONICET, Junín 956, 1113AAD, C.A.B.A, Argentina
| | - Lucía Daniela Espeche
- Departamento de Diagnóstico Genético, Centro Nacional de Genética Médica "Dr. Eduardo E. Castilla"-A.N.L.I.S, Av. Las Heras 2670, C1425ASQ, C.A.B.A, Argentina
| | - María Georgina Herrera
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
| | - Martín Ezequiel Noguera
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
- Intituto de Química y Fisicoquímica Biológicas, Dr. Alejandro Paladini Universidad de Buenos Aires, CONICET, Junín 956, 1113AAD, C.A.B.A, Argentina
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Sáenz Peña 352, B1876BXD, Bernal, Provincia de Buenos Aires, Argentina
| | - Liliana Dain
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
- Departamento de Diagnóstico Genético, Centro Nacional de Genética Médica "Dr. Eduardo E. Castilla"-A.N.L.I.S, Av. Las Heras 2670, C1425ASQ, C.A.B.A, Argentina
| | - Alejandro Daniel Nadra
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Martín Aran
- Fundación Instituto Leloir E IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina
| | - Clara Smal
- Fundación Instituto Leloir E IIBBA-CONICET, Av. Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina
| | - Mariana Gallo
- IRBM Science Park S.p.A, Via Pontina km 30,600, 00071, Pomezia, RM, Italy
| | - Javier Santos
- Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencia Exactas y Naturales, Instituto de Biociencias, Biotecnología y Biomedicina (iB3), Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA, C.A.B.A, Argentina.
- Intituto de Química y Fisicoquímica Biológicas, Dr. Alejandro Paladini Universidad de Buenos Aires, CONICET, Junín 956, 1113AAD, C.A.B.A, Argentina.
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15
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Guo L, Wang Q, Weng L, Hauser LA, Strawser CJ, Mesaros C, Lynch DR, Blair IA. Characterization of a new N-terminally acetylated extra-mitochondrial isoform of frataxin in human erythrocytes. Sci Rep 2018; 8:17043. [PMID: 30451920 PMCID: PMC6242848 DOI: 10.1038/s41598-018-35346-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/02/2018] [Indexed: 01/18/2023] Open
Abstract
Frataxin is a highly conserved protein encoded by the frataxin (FXN) gene. The full-length 210-amino acid form of protein frataxin (1-210; isoform A) expressed in the cytosol of cells rapidly translocates to the mitochondria, where it is converted to the mature form (81-210) by mitochondrial processing peptidase. Mature frataxin (81-210) is a critically important protein because it facilitates the assembly of mitochondrial iron-sulfur cluster protein complexes such as aconitase, lipoate synthase, and succinate dehydrogenases. Decreased expression of frataxin protein is responsible for the devastating rare genetic disease of Friedreich's ataxia. The mitochondrial form of frataxin has long been thought to be present in erythrocytes even though paradoxically, erythrocytes lack mitochondria. We have discovered that erythrocyte frataxin is in fact a novel isoform of frataxin (isoform E) with 135-amino acids and an N-terminally acetylated methionine residue. There is three times as much isoform E in erythrocytes (20.9 ± 6.4 ng/mL) from the whole blood of healthy volunteers (n = 10) when compared with the mature mitochondrial frataxin present in other blood cells (7.1 ± 1.0 ng/mL). Isoform E lacks a mitochondrial targeting sequence and so is distributed to both cytosol and the nucleus when expressed in cultured cells. When extra-mitochondrial frataxin isoform E is expressed in HEK 293 cells, it is converted to a shorter isoform identical to the mature frataxin found in mitochondria, which raises the possibility that it is involved in disease etiology. The ability to specifically quantify extra-mitochondrial and mitochondrial isoforms of frataxin in whole blood will make it possible to readily follow the natural history of diseases such as Friedreich's ataxia and monitor the efficacy of therapeutic interventions.
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Affiliation(s)
- Lili Guo
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
| | - Qingqing Wang
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
| | - Liwei Weng
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Lauren A Hauser
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Cassandra J Strawser
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Clementina Mesaros
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
| | - David R Lynch
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
- Departments of Pediatrics and Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Ian A Blair
- Penn SRP Center and Center of Excellence in Environmental Toxicology Center, Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States.
- Penn/CHOP Center of Excellence in Friedreich's ataxia, Philadelphia, PA, 19104, United States.
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16
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Chiabrando D, Fiorito V, Petrillo S, Tolosano E. Unraveling the Role of Heme in Neurodegeneration. Front Neurosci 2018; 12:712. [PMID: 30356807 PMCID: PMC6189481 DOI: 10.3389/fnins.2018.00712] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/19/2018] [Indexed: 12/24/2022] Open
Abstract
Heme (iron-protoporphyrin IX) is an essential co-factor involved in several biological processes, including neuronal survival and differentiation. Nevertheless, an excess of free-heme promotes oxidative stress and lipid peroxidation, thus leading to cell death. The toxic properties of heme in the brain have been extensively studied during intracerebral or subarachnoid hemorrhages. Recently, a growing number of neurodegenerative disorders have been associated to alterations of heme metabolism. Hence, the etiology of such diseases remains undefined. The aim of this review is to highlight the neuropathological role of heme and to discuss the major heme-regulated pathways that might be crucial for the survival of neuronal cells. The understanding of the molecular mechanisms linking heme to neurodegeneration will be important for therapeutic purposes.
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Affiliation(s)
- Deborah Chiabrando
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
| | - Veronica Fiorito
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
| | - Sara Petrillo
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
| | - Emanuela Tolosano
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
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17
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Mitochondrial Targeting in Neurodegeneration: A Heme Perspective. Pharmaceuticals (Basel) 2018; 11:ph11030087. [PMID: 30231533 PMCID: PMC6161291 DOI: 10.3390/ph11030087] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/07/2018] [Accepted: 09/14/2018] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial dysfunction has achieved an increasing interest in the field of neurodegeneration as a pathological hallmark for different disorders. The impact of mitochondria is related to a variety of mechanisms and several of them can co-exist in the same disease. The central role of mitochondria in neurodegenerative disorders has stimulated studies intended to implement therapeutic protocols based on the targeting of the distinct mitochondrial processes. The review summarizes the most relevant mechanisms by which mitochondria contribute to neurodegeneration, encompassing therapeutic approaches. Moreover, a new perspective is proposed based on the heme impact on neurodegeneration. The heme metabolism plays a central role in mitochondrial functions, and several evidences indicate that alterations of the heme metabolism are associated with neurodegenerative disorders. By reporting the body of knowledge on this topic, the review intends to stimulate future studies on the role of heme metabolism in neurodegeneration, envisioning innovative strategies in the struggle against neurodegenerative diseases.
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18
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Chiang S, Kalinowski DS, Jansson PJ, Richardson DR, Huang MLH. Mitochondrial dysfunction in the neuro-degenerative and cardio-degenerative disease, Friedreich's ataxia. Neurochem Int 2018; 117:35-48. [PMID: 28782591 DOI: 10.1016/j.neuint.2017.08.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 07/25/2017] [Accepted: 08/03/2017] [Indexed: 01/09/2023]
Abstract
Mitochondrial homeostasis is essential for maintaining healthy cellular function and survival. The detrimental involvement of mitochondrial dysfunction in neuro-degenerative diseases has recently been highlighted in human conditions, such as Parkinson's, Alzheimer's and Huntington's disease. Friedreich's ataxia (FA) is another neuro-degenerative, but also cardio-degenerative condition, where mitochondrial dysfunction plays a crucial role in disease progression. Deficient expression of the mitochondrial protein, frataxin, is the primary cause of FA, which leads to adverse alterations in whole cell and mitochondrial iron metabolism. Dys-regulation of iron metabolism in these compartments, results in the accumulation of inorganic iron deposits in the mitochondrial matrix that is thought to potentiate oxidative damage observed in FA. Therefore, the maintenance of mitochondrial homeostasis is crucial in the progression of neuro-degenerative conditions, particularly in FA. In this review, vital mitochondrial homeostatic processes and their roles in FA pathogenesis will be discussed. These include mitochondrial iron processing, mitochondrial dynamics (fusion and fission processes), mitophagy, mitochondrial biogenesis, mitochondrial energy production and calcium metabolism.
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Affiliation(s)
- Shannon Chiang
- Department of Pathology and Bosch Institute, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Danuta S Kalinowski
- Department of Pathology and Bosch Institute, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Patric J Jansson
- Department of Pathology and Bosch Institute, University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Des R Richardson
- Department of Pathology and Bosch Institute, University of Sydney, Sydney, New South Wales, 2006, Australia.
| | - Michael L-H Huang
- Department of Pathology and Bosch Institute, University of Sydney, Sydney, New South Wales, 2006, Australia.
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19
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Roy AR, Ahmed A, DiStefano PV, Chi L, Khyzha N, Galjart N, Wilson MD, Fish JE, Delgado-Olguín P. The transcriptional regulator CCCTC-binding factor limits oxidative stress in endothelial cells. J Biol Chem 2018; 293:8449-8461. [PMID: 29610276 PMCID: PMC5986204 DOI: 10.1074/jbc.m117.814699] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 03/28/2018] [Indexed: 12/22/2022] Open
Abstract
The CCCTC-binding factor (CTCF) is a versatile transcriptional regulator required for embryogenesis, but its function in vascular development or in diseases with a vascular component is poorly understood. Here, we found that endothelial Ctcf is essential for mouse vascular development and limits accumulation of reactive oxygen species (ROS). Conditional knockout of Ctcf in endothelial progenitors and their descendants affected embryonic growth, and caused lethality at embryonic day 10.5 because of defective yolk sac and placental vascular development. Analysis of global gene expression revealed Frataxin (Fxn), the gene mutated in Friedreich's ataxia (FRDA), as the most strongly down-regulated gene in Ctcf-deficient placental endothelial cells. Moreover, in vitro reporter assays showed that Ctcf activates the Fxn promoter in endothelial cells. ROS are known to accumulate in the endothelium of FRDA patients. Importantly, Ctcf deficiency induced ROS-mediated DNA damage in endothelial cells in vitro, and in placental endothelium in vivo Taken together, our findings indicate that Ctcf promotes vascular development and limits oxidative stress in endothelial cells. These results reveal a function for Ctcf in vascular development, and suggest a potential mechanism for endothelial dysfunction in FRDA.
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Affiliation(s)
- Anna R Roy
- From the Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Abdalla Ahmed
- From the Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Peter V DiStefano
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 2C4, Canada
| | - Lijun Chi
- From the Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Nadiya Khyzha
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 2C4, Canada
| | - Niels Galjart
- Department of Cell Biology and Genetics, Erasmus Medical Center, Rotterdam 3015 CN, The Netherlands
| | - Michael D Wilson
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Genetics and Genome Biology Research Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada
| | - Jason E Fish
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario M5G 2C4, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
- Heart and Stroke Richard Lewar Centre of Excellence in Cardiovascular Research, Toronto, Ontario M5S 3H2, Canada
| | - Paul Delgado-Olguín
- From the Translational Medicine Research Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada,
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Heart and Stroke Richard Lewar Centre of Excellence in Cardiovascular Research, Toronto, Ontario M5S 3H2, Canada
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20
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Télot L, Rousseau E, Lesuisse E, Garcia C, Morlet B, Léger T, Camadro JM, Serre V. Quantitative proteomics in Friedreich's ataxia B-lymphocytes: A valuable approach to decipher the biochemical events responsible for pathogenesis. Biochim Biophys Acta Mol Basis Dis 2018; 1864:997-1009. [DOI: 10.1016/j.bbadis.2018.01.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/19/2017] [Accepted: 01/08/2018] [Indexed: 11/29/2022]
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21
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Intrinsic Disorder in Proteins with Pathogenic Repeat Expansions. Molecules 2017; 22:molecules22122027. [PMID: 29186753 PMCID: PMC6149999 DOI: 10.3390/molecules22122027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.
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22
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Buchensky C, Sánchez M, Carrillo M, Palacios O, Capdevila M, Domínguez-Vera JM, Busi MV, Atrian S, Pagani MA, Gomez-Casati DF. Identification of two frataxin isoforms in Zea mays: Structural and functional studies. Biochimie 2017; 140:34-47. [PMID: 28630009 DOI: 10.1016/j.biochi.2017.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/15/2017] [Indexed: 11/19/2022]
Abstract
Frataxin is a ubiquitous protein that plays a role in Fe-S cluster biosynthesis and iron and heme metabolism, although its molecular functions are not entirely clear. In non-photosynthetic eukaryotes, frataxin is encoded by a single gene, and the protein localizes to mitochondria. Here we report the presence of two functional frataxin isoforms in Zea mays, ZmFH-1 and ZmFH-2. We confirmed our previous findings regarding plant frataxins: both proteins have dual localization in mitochondria and chloroplasts. Physiological, biochemical and biophysical studies show some differences in the expression pattern, protection against oxidants and in the aggregation state of both isoforms, suggesting that the two frataxin homologs would play similar but not identical roles in plant cell metabolism. In addition, two specific features of plant frataxins were evidenced: their ability to form dimers and their tendency to undergo conformational change under oxygen exposure.
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Affiliation(s)
- Celeste Buchensky
- CEFOBI - CONICET, Centro de Estudios Fotosintéticos y Bioquímicos - Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Manuel Sánchez
- Departamento de Química Inorgánica, Facultad de Ciencias. Instituto de Biotecnología, Universidad de Granada, 18071, Granada, Spain
| | - Martin Carrillo
- CEFOBI - CONICET, Centro de Estudios Fotosintéticos y Bioquímicos - Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Oscar Palacios
- Departament de Química, Facultat de Ciènces, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain
| | - Mercè Capdevila
- Departament de Química, Facultat de Ciènces, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Barcelona, Spain
| | - Jose M Domínguez-Vera
- Departamento de Química Inorgánica, Facultad de Ciencias. Instituto de Biotecnología, Universidad de Granada, 18071, Granada, Spain
| | - Maria V Busi
- CEFOBI - CONICET, Centro de Estudios Fotosintéticos y Bioquímicos - Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Sílvia Atrian
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Maria A Pagani
- CEFOBI - CONICET, Centro de Estudios Fotosintéticos y Bioquímicos - Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina
| | - Diego F Gomez-Casati
- CEFOBI - CONICET, Centro de Estudios Fotosintéticos y Bioquímicos - Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Santa Fe, Argentina.
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23
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Steinkellner H, Singh HN, Muckenthaler MU, Goldenberg H, Moganty RR, Scheiber-Mojdehkar B, Sturm B. No changes in heme synthesis in human Friedreich´s ataxia erythroid progenitor cells. Gene 2017; 621:5-11. [PMID: 28412459 DOI: 10.1016/j.gene.2017.04.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 12/28/2022]
Abstract
Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by reduced expression of the protein frataxin. Frataxin is thought to play a role in iron-sulfur cluster biogenesis and heme synthesis. In this study, we used erythroid progenitor stem cells obtained from FRDA patients and healthy donors to investigate the putative role, if any, of frataxin deficiency in heme synthesis. We used electrochemiluminescence and qRT-PCR for frataxin protein and mRNA quantification. We used atomic absorption spectrophotometry for iron levels and a photometric assay for hemoglobin levels. Protoporphyrin IX and Ferrochelatase were analyzed using auto-fluorescence. An "IronChip" microarray analysis followed by a protein-protein interaction analysis was performed. FRDA patient cells showed no significant changes in iron levels, hemoglobin synthesis, protoporphyrin IX levels, and ferrochelatase activity. Microarray analysis presented 11 genes that were significantly changed in all patients compared to controls. The genes are especially involved in oxidative stress, iron homeostasis and angiogenesis. The mystery about the involvement of frataxin on iron metabolism raises the question why frataxin deficiency in primary FRDA cells did not lead to changes in biochemical parameters of heme synthesis. It seems that alternative pathways can circumvent the impact of frataxin deficiency on heme synthesis. We show for the first time in primary FRDA patient cells that reduced frataxin levels are still sufficient for heme synthesis and possibly other mechanisms can overcome reduced frataxin levels in this process. Our data strongly support the fact that so far no anemia in FRDA patients was reported.
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Affiliation(s)
- Hannes Steinkellner
- Department of Medical Chemistry and Pathobiochemistry, Medical University of Vienna, Vienna, Austria; Department of Medical Genetics, Medical University of Vienna, Vienna, Austria
| | - Himanshu Narayan Singh
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
| | | | - Hans Goldenberg
- Department of Medical Chemistry and Pathobiochemistry, Medical University of Vienna, Vienna, Austria
| | - Rajeswari R Moganty
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110029, India
| | | | - Brigitte Sturm
- Department of Medical Chemistry and Pathobiochemistry, Medical University of Vienna, Vienna, Austria.
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24
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Chiang S, Kovacevic Z, Sahni S, Lane DJR, Merlot AM, Kalinowski DS, Huang MLH, Richardson DR. Frataxin and the molecular mechanism of mitochondrial iron-loading in Friedreich's ataxia. Clin Sci (Lond) 2016; 130:853-70. [PMID: 27129098 DOI: 10.1042/cs20160072] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/16/2016] [Indexed: 12/19/2022]
Abstract
The mitochondrion is a major site for the metabolism of the transition metal, iron, which is necessary for metabolic processes critical for cell vitality. The enigmatic mitochondrial protein, frataxin, is known to play a significant role in both cellular and mitochondrial iron metabolism due to its iron-binding properties and its involvement in iron-sulfur cluster (ISC) and heme synthesis. The inherited neuro- and cardio-degenerative disease, Friedreich's ataxia (FA), is caused by the deficient expression of frataxin that leads to deleterious alterations in iron metabolism. These changes lead to the accumulation of inorganic iron aggregates in the mitochondrial matrix that are presumed to play a key role in the oxidative damage and subsequent degenerative features of this disease. Furthermore, the concurrent dys-regulation of cellular antioxidant defense, which coincides with frataxin deficiency, exacerbates oxidative stress. Hence, the pathogenesis of FA underscores the importance of the integrated homeostasis of cellular iron metabolism and the cytoplasmic and mitochondrial redox environments. This review focuses on describing the pathogenesis of the disease, the molecular mechanisms involved in mitochondrial iron-loading and the dys-regulation of cellular antioxidant defense due to frataxin deficiency. In turn, current and emerging therapeutic strategies are also discussed.
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Affiliation(s)
- Shannon Chiang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Zaklina Kovacevic
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Sumit Sahni
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Angelica M Merlot
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Danuta S Kalinowski
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael L-H Huang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia )
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia )
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25
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Wang L, Tian D, Hu J, Xing H, Sun M, Wang J, Jian Q, Yang H. MiRNA-145 Regulates the Development of Congenital Heart Disease Through Targeting FXN. Pediatr Cardiol 2016; 37:629-36. [PMID: 26717909 DOI: 10.1007/s00246-015-1325-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 12/11/2015] [Indexed: 11/30/2022]
Abstract
Congenital heart disease (CHD) is the leading cause of death in infants in the world. The study of CHDs has come a long way since their classification and description. Although transcriptional programmes that are impaired in individuals with CHDs are being identified, the mechanisms of how these deficiencies translate to a structural defect are unknown. In this study, using high-throughput microarray analysis and molecular network analysis, FXN was identified to be the most differentially expressed key gene in CHD. By TargetScan analysis, we predicted FXN was the target gene of miRNA-145 and miRNA-182. Through real-time PCR analysis of clinical samples and experiments in cell lines, we confirmed that miRNA-145 but not miRNA-182 directly binds to the 3' UTR region of FXN and negatively regulates its expression. We further found that through targeting FXN, miRNA-145 regulates apoptosis and mitochondrial function. In general, our study confirmed the differentially expressed FXN regulates the development of CHD and the differential expression was under the control of miRNA-145. These results might provide new insight into the understanding of the CHD pathogenesis and may facilitate further therapeutic studies.
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Affiliation(s)
- Lei Wang
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China.
| | - Danqiu Tian
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
| | - Jihua Hu
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
| | - Haijian Xing
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
| | - Min Sun
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
| | - Juanli Wang
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
| | - Qiang Jian
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
| | - Hua Yang
- Department of Cardiology, Xi'an Children's Hospital, No. 69, Xiju RD, Lianhu District, Xi'an, 710003, Shaanxi, China
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26
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Modjtahedi N, Tokatlidis K, Dessen P, Kroemer G. Mitochondrial Proteins Containing Coiled-Coil-Helix-Coiled-Coil-Helix (CHCH) Domains in Health and Disease. Trends Biochem Sci 2016; 41:245-260. [PMID: 26782138 DOI: 10.1016/j.tibs.2015.12.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 12/08/2015] [Accepted: 12/15/2015] [Indexed: 11/19/2022]
Abstract
Members of the coiled-coil-helix-coiled-coil-helix (CHCH) domain-containing protein family that carry (CX9C) type motifs are imported into the mitochondrion with the help of the disulfide relay-dependent MIA import pathway. These evolutionarily conserved proteins are emerging as new cellular factors that control mitochondrial respiration, redox regulation, lipid homeostasis, and membrane ultrastructure and dynamics. We discuss recent insights on the activity of known (CX9C) motif-carrying proteins in mammals and review current data implicating the Mia40/CHCHD4 import machinery in the regulation of their mitochondrial import. Recent findings and the identification of disease-associated mutations in specific (CX9C) motif-carrying proteins have highlighted members of this family of proteins as potential therapeutic targets in a variety of human disorders.
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Affiliation(s)
- Nazanine Modjtahedi
- Institut National de la Santé et de la Recherche Médicale, U1030, Villejuif, France; Gustave Roussy Cancer Campus, Villejuif, France; Faculty of Medicine, Université Paris-Saclay, Kremlin-Bicêtre, France.
| | - Kostas Tokatlidis
- Institute of Molecular Cell and Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Philippe Dessen
- Gustave Roussy Cancer Campus, Villejuif, France; Faculty of Medicine, Université Paris-Saclay, Kremlin-Bicêtre, France; Groupe bioinformatique Gustave Roussy Cancer Campus, Villejuif, France
| | - Guido Kroemer
- Equipe 11 Labellisée Ligue Nationale Contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Institut National de la Santé et de la Recherche Médicale, U1138, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie, Paris, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, Paris, AP-HP, France; Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden.
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27
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Zhang Y, Maurizi MR. Mitochondrial ClpP activity is required for cisplatin resistance in human cells. Biochim Biophys Acta Mol Basis Dis 2015; 1862:252-64. [PMID: 26675528 DOI: 10.1016/j.bbadis.2015.12.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 11/05/2015] [Accepted: 12/04/2015] [Indexed: 02/07/2023]
Abstract
In human cells ClpP and ClpX are imported into the mitochondrial matrix, where they interact to form the ATP-dependent protease ClpXP and play a role in the mitochondrial unfolded protein response. We find that reducing the levels of mitochondrial ClpP or ClpX renders human cancer cells more sensitive to cisplatin, a widely used anti-cancer drug. Conversely, overexpression of HClpP desensitizes cells to cisplatin. Overexpression of inactive HClpP-S97A had no effect. Cisplatin resistance correlated with decreased cellular accumulation of cisplatin and decreased levels of diguanosine-cisplatin adducts in both mitochondrial and genomic DNA. In contrast, higher levels of cisplatin-DNA adducts were found in cells in which HClpP had been depleted. Changes in the levels of ClpP had no effect on the levels of CTR1, a copper transporter that contributes to cisplatin uptake. However, the levels of ATP7A and ATP7B, copper efflux pumps that help eliminate cisplatin from cells, were increased when HClpP was overexpressed. HClpP levels were elevated in cervical carcinoma cells (KB-CP20) and hepatoma cells (BEL-7404-CP20) independently selected for cisplatin resistance. The data indicate that robust HClpXP activity positively affects the ability of cells to efflux cisplatin and suggest that targeting HClpP or HClpX would offer a novel mechanism for sensitizing cancer cells to cisplatin.
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Affiliation(s)
- Yang Zhang
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Michael R Maurizi
- Laboratory of Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States.
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28
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Turowski VR, Aknin C, Maliandi MV, Buchensky C, Leaden L, Peralta DA, Busi MV, Araya A, Gomez-Casati DF. Frataxin Is Localized to Both the Chloroplast and Mitochondrion and Is Involved in Chloroplast Fe-S Protein Function in Arabidopsis. PLoS One 2015; 10:e0141443. [PMID: 26517126 PMCID: PMC4636843 DOI: 10.1371/journal.pone.0141443] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/07/2015] [Indexed: 11/19/2022] Open
Abstract
Frataxin plays a key role in eukaryotic cellular iron metabolism, particularly in mitochondrial heme and iron-sulfur (Fe-S) cluster biosynthesis. However, its precise role has yet to be elucidated. In this work, we studied the subcellular localization of Arabidopsis frataxin, AtFH, using confocal microscopy, and found a novel dual localization for this protein. We demonstrate that plant frataxin is targeted to both the mitochondria and the chloroplast, where it may play a role in Fe-S cluster metabolism as suggested by functional studies on nitrite reductase (NIR) and ferredoxin (Fd), two Fe-S containing chloroplast proteins, in AtFH deficient plants. Our results indicate that frataxin deficiency alters the normal functioning of chloroplasts by affecting the levels of Fe, chlorophyll, and the photosynthetic electron transport chain in this organelle.
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Affiliation(s)
- Valeria R. Turowski
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina
| | - Cindy Aknin
- UMR5234 Microbiologie Fondamentale et Pathogénicité, Centre National de la Recherche Scientifique and Université Bordeaux-Segalen, 146 rue Léo Saignat, 33076, Bordeaux cedex, France
| | - Maria V. Maliandi
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH) CONICET/UNSAM, Camino de Circunvaación Km 6, 7130, Chascomús, Argentina
| | - Celeste Buchensky
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina
| | - Laura Leaden
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina
| | - Diego A. Peralta
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina
| | - Maria V. Busi
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina
| | - Alejandro Araya
- Centre National de la Recherche Scientifique & UMR 1332 –Biologie du Fruit et Pathologie, Institute National de la Recherche Agronomique (INRA) Bordeaux Aquitaine, 71 avenue Edouard Bourlaux, 33882, Villenave D’Ornon, France
| | - Diego F. Gomez-Casati
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario, Suipacha 531, 2000, Rosario, Argentina
- * E-mail:
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29
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Compartmentalization of iron between mitochondria and the cytosol and its regulation. Eur J Cell Biol 2015; 94:292-308. [DOI: 10.1016/j.ejcb.2015.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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30
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Lane DJR, Merlot AM, Huang MLH, Bae DH, Jansson PJ, Sahni S, Kalinowski DS, Richardson DR. Cellular iron uptake, trafficking and metabolism: Key molecules and mechanisms and their roles in disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1130-44. [PMID: 25661197 DOI: 10.1016/j.bbamcr.2015.01.021] [Citation(s) in RCA: 253] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/09/2015] [Accepted: 01/28/2015] [Indexed: 01/08/2023]
Abstract
Iron is a crucial transition metal for virtually all life. Two major destinations of iron within mammalian cells are the cytosolic iron-storage protein, ferritin, and mitochondria. In mitochondria, iron is utilized in critical anabolic pathways, including: iron-storage in mitochondrial ferritin, heme synthesis, and iron-sulfur cluster (ISC) biogenesis. Although the pathways involved in ISC synthesis in the mitochondria and cytosol have begun to be characterized, many crucial details remain unknown. In this review, we discuss major aspects of the journey of iron from its initial cellular uptake, its modes of trafficking within cells, to an overview of its downstream utilization in the cytoplasm and within mitochondria. The understanding of mitochondrial iron processing and its communication with other organelles/subcellular locations, such as the cytosol, has been elucidated by the analysis of certain diseases e.g., Friedreich's ataxia. Increased knowledge of the molecules and their mechanisms of action in iron processing pathways (e.g., ISC biogenesis) will shape the investigation of iron metabolism in human health and disease.
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Affiliation(s)
- D J R Lane
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia.
| | - A M Merlot
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia
| | - M L-H Huang
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia
| | - D-H Bae
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia
| | - P J Jansson
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia
| | - S Sahni
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia
| | - D S Kalinowski
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia
| | - D R Richardson
- Department of Pathology and Bosch Institute, Molecular Pharmacology and Pathology Program, Blackburn Building, University of Sydney, Sydney, New South Wales 2006, Australia.
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31
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Shimizu R, Lan NN, Tai TT, Adachi Y, Kawazoe A, Mu A, Taketani S. p53 directly regulates the transcription of the human frataxin gene and its lack of regulation in tumor cells decreases the utilization of mitochondrial iron. Gene 2014; 551:79-85. [PMID: 25158131 DOI: 10.1016/j.gene.2014.08.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/19/2014] [Accepted: 08/21/2014] [Indexed: 02/05/2023]
Abstract
Mitochondrial frataxin functions in iron homeostasis, biogenesis of iron-sulfur clusters, protection from oxidative stress and apoptosis, and as a tumor suppressor protein. We examined regulation of the expression of the human frataxin by p53. Pifithrin-α, an inhibitor of p53 function, and knockdown of p53 decreased the level of frataxin mRNA in human kidney HEK 293T cells. The transcriptional activity of the human frataxin gene is enhanced by the proximal promoter containing the p53-responsive element (p53RE) on the gene. Chromatin immunoprecipitation assay and electrophoretic mobility shift assay confirmed the binding of p53 to the human frataxin p53RE. The expression of wild-type p53 in human cancer HeLa cells increased the reporter activity carrying p53RE at the region of -209 to -200bp of the frataxin promoter. Finally, when the HeLa cells overexpressing frataxin were treated with 5-aminolevulinic acid (ALA), there was less accumulation of protoporphyrin than HeLa control cells, and it was sharply decreased by the addition of iron citrate, suggesting that the utilization of mitochondrial iron for heme biosynthesis can be dependent on the level of frataxin. Alternatively, the low expression of frataxin not regulated by p53 in tumor cells lowers the utilization of iron in mitochondria, causing the tumor-specific ALA-induced accumulation of protoporphyrin.
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Affiliation(s)
- Rina Shimizu
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Nguyen Ngoc Lan
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Tran Tien Tai
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Yuka Adachi
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Asako Kawazoe
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Anfeng Mu
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan
| | - Shigeru Taketani
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto 606-8585, Japan; Insect Biomedical Center, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
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32
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Papadopoulou LC, Kyriazou AV, Bonovolias ID, Tsiftsoglou AS. Imatinib inhibits the expression of SCO2 and FRATAXIN genes that encode mitochondrial proteins in human Bcr-Abl⁺ leukemia cells. Blood Cells Mol Dis 2014; 53:84-90. [PMID: 24726617 DOI: 10.1016/j.bcmd.2014.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/06/2014] [Accepted: 03/06/2014] [Indexed: 12/19/2022]
Abstract
Imatinib mesylate (IM/Gleevec®), a selective inhibitor of chimeric Bcr-Abl tyrosine kinase, was developed as a first line drug to treat CML and ALL Ph(+) patients. Earlier studies have shown that hemin counteracts the IM-induced cell killing in human K-562 CML cells. In this study, we investigated whether IM disrupts the heme-dependent Cytochrome c Oxidase (COX) Biosynthesis and Assembly Pathway (HDCBAP) in Bcr-Abl(+) and Bcr-Abl(-) cells by affecting the expression of key-genes. Cells were exposed to IM and evaluated at time intervals for cell growth, cell death, expression of various genes by RT-PCR analysis as well as Sco2 mature protein levels by western blot analysis and COX enzymatic activity. IM at 1 μM induced extensive cell growth inhibition and cell death as well as marked suppression of the expression of SCO2 and FRATAXIN (FXN) genes in human K-562 and KU-812 Bcr-Abl(+) CML cells. IM also reduced the protein level of mature Sco2 mitochondrial protein as well as COX activity in these cell lines. However, treatment of human MOLT-4 Bcr-Abl(-) cells with 1μM and even with higher concentrations (4×10(-5)M) of IM neither reduced the expression of SCO2 and FXN genes nor suppressed the protein level of mature Sco2 protein and COX activity. Our findings indicate that SCO2 and FXN genes, involved in HDCBAP, are repressed by IM in human Bcr-Abl(+) CML cells and may represent novel target sites in leukemia therapy.
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Affiliation(s)
- Lefkothea C Papadopoulou
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki (A.U.TH.), GR-54124 Thessaloniki, Macedonia, Greece
| | - Angeliki V Kyriazou
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki (A.U.TH.), GR-54124 Thessaloniki, Macedonia, Greece
| | - Ioannis D Bonovolias
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki (A.U.TH.), GR-54124 Thessaloniki, Macedonia, Greece
| | - Asterios S Tsiftsoglou
- Laboratory of Pharmacology, Department of Pharmaceutical Sciences, Aristotle University of Thessaloniki (A.U.TH.), GR-54124 Thessaloniki, Macedonia, Greece.
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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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Pastore A, Puccio H. Frataxin: a protein in search for a function. J Neurochem 2013; 126 Suppl 1:43-52. [PMID: 23859340 DOI: 10.1111/jnc.12220] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 01/18/2013] [Accepted: 01/23/2013] [Indexed: 01/01/2023]
Abstract
Reduced levels of the protein frataxin cause the neurodegenerative disease Friedreich's ataxia. Pathology is associated with disruption of iron-sulfur cluster biosynthesis, mitochondrial iron overload, and oxidative stress. Frataxin is a highly conserved iron-binding protein present in most organisms. Despite the intense interest generated since the determination of its pathology, identification of the cellular function of frataxin has so far remained elusive. In this review, we revisit the most significant milestones that have led us to our current understanding of frataxin and its functions. The picture that emerges is that frataxin is a crucial element of one of the most essential cellular machines specialized in iron-sulfur cluster biogenesis. Future developments, therefore, can be expected from further advancements in our comprehension of this machine.
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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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Sawamoto M, Imai T, Umeda M, Fukuda K, Kataoka T, Taketani S. The p53-dependent expression of frataxin controls 5-aminolevulinic acid-induced accumulation of protoporphyrin IX and photo-damage in cancerous cells. Photochem Photobiol 2013; 89:163-72. [PMID: 22862424 DOI: 10.1111/j.1751-1097.2012.01215.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 07/25/2012] [Indexed: 11/29/2022]
Abstract
Mitochondrial frataxin is involved in various functions such as iron homeostasis, iron-sulfur cluster biogenesis, the protection from oxidative stress and apoptosis and acts as a tumor suppressor protein. We now show that the expression of frataxin is stimulated in a p53-dependent manner and prove that frataxin is a direct p53 target gene by showing that the p53-responsive element in the promoter of the mouse frataxin gene is bound by p53. The bacterial expression of human frataxin stimulated maturation of human ferrochelatase, which catalyzes the insertion of iron into protoporphyrin at the last step of heme biosynthesis. Overexpression of frataxin in human cancer A431 and HeLa cells lowered 5-aminolevulinic acid(ALA)-induced accumulation of protoporphyrin and induced resistance to ALA-induced photo-damage, whereas p53 silencing with siRNA in non tumor HEK293T cells down-regulated the expression of frataxin and increased the accumulation of protoporphyrin. Thus, the decrease of the expression of frataxin unregulated by p53 in tumor cells enhances ALA-induced photo-damage, by down-regulation of mitochondrial functions.
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Affiliation(s)
- Mari Sawamoto
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto, Japan
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Lill R, Hoffmann B, Molik S, Pierik AJ, Rietzschel N, Stehling O, Uzarska MA, Webert H, Wilbrecht C, Mühlenhoff U. The role of mitochondria in cellular iron-sulfur protein biogenesis and iron metabolism. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:1491-508. [PMID: 22609301 DOI: 10.1016/j.bbamcr.2012.05.009] [Citation(s) in RCA: 364] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 12/21/2022]
Abstract
Mitochondria play a key role in iron metabolism in that they synthesize heme, assemble iron-sulfur (Fe/S) proteins, and participate in cellular iron regulation. Here, we review the latter two topics and their intimate connection. The mitochondrial Fe/S cluster (ISC) assembly machinery consists of 17 proteins that operate in three major steps of the maturation process. First, the cysteine desulfurase complex Nfs1-Isd11 as the sulfur donor cooperates with ferredoxin-ferredoxin reductase acting as an electron transfer chain, and frataxin to synthesize an [2Fe-2S] cluster on the scaffold protein Isu1. Second, the cluster is released from Isu1 and transferred toward apoproteins with the help of a dedicated Hsp70 chaperone system and the glutaredoxin Grx5. Finally, various specialized ISC components assist in the generation of [4Fe-4S] clusters and cluster insertion into specific target apoproteins. Functional defects of the core ISC assembly machinery are signaled to cytosolic or nuclear iron regulatory systems resulting in increased cellular iron acquisition and mitochondrial iron accumulation. In fungi, regulation is achieved by iron-responsive transcription factors controlling the expression of genes involved in iron uptake and intracellular distribution. They are assisted by cytosolic multidomain glutaredoxins which use a bound Fe/S cluster as iron sensor and additionally perform an essential role in intracellular iron delivery to target metalloproteins. In mammalian cells, the iron regulatory proteins IRP1, an Fe/S protein, and IRP2 act in a post-transcriptional fashion to adjust the cellular needs for iron. Thus, Fe/S protein biogenesis and cellular iron metabolism are tightly linked to coordinate iron supply and utilization. This article is part of a Special Issue entitled: Cell Biology of Metals.
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Affiliation(s)
- Roland Lill
- Institut für Zytobiologie und Zytopathologie, Philipps-Universität Marburg, Robert-Koch Str. 6, 35033 Marburg, Germany.
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Rines AK, Ardehali H. Transition metals and mitochondrial metabolism in the heart. J Mol Cell Cardiol 2012; 55:50-7. [PMID: 22668786 DOI: 10.1016/j.yjmcc.2012.05.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 05/23/2012] [Accepted: 05/25/2012] [Indexed: 12/12/2022]
Abstract
Transition metals are essential to many biological processes in almost all organisms from bacteria to humans. Their versatility, which arises from an ability to undergo reduction-oxidation chemistry, enables them to act as critical cofactors of enzymes throughout the cell. Accumulation of metals, however, can also lead to oxidative stress and cellular damage. The importance of metals to both enzymatic reactions and oxidative stress makes them key players in mitochondria. Mitochondria are the primary energy-generating organelles of the cell that produce ATP through a chain of enzymatic complexes that require transition metals, and are highly sensitive to oxidative damage. Moreover, the heart is one of the most mitochondrially-rich tissues in the body, making metals of particular importance to cardiac function. In this review, we focus on the current knowledge about the role of transition metals (specifically iron, copper, and manganese) in mitochondrial metabolism in the heart. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism".
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Affiliation(s)
- Amy K Rines
- Feinberg Cardiovascular Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Research on plants for the understanding of diseases of nuclear and mitochondrial origin. J Biomed Biotechnol 2012; 2012:836196. [PMID: 22690124 PMCID: PMC3368588 DOI: 10.1155/2012/836196] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 03/28/2012] [Indexed: 11/17/2022] Open
Abstract
Different model organisms, such as Escherichia coli, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, mouse, cultured human cell lines, among others, were used to study the mechanisms of several human diseases. Since human genes and proteins have been structurally and functionally conserved in plant organisms, the use of plants, especially Arabidopsis thaliana, as a model system to relate molecular defects to clinical disorders has recently increased. Here, we briefly review our current knowledge of human diseases of nuclear and mitochondrial origin and summarize the experimental findings of plant homologs implicated in each process.
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Huang MLH, Lane DJR, Richardson DR. Mitochondrial mayhem: the mitochondrion as a modulator of iron metabolism and its role in disease. Antioxid Redox Signal 2011; 15:3003-19. [PMID: 21545274 DOI: 10.1089/ars.2011.3921] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mitochondrion plays vital roles in various aspects of cellular metabolism, ranging from energy transduction and apoptosis to the synthesis of important molecules such as heme. Mitochondria are also centrally involved in iron metabolism, as exemplified by disruptions in mitochondrial proteins that lead to perturbations in whole-cell iron processing. Recent investigations have identified a host of mitochondrial proteins (e.g., mitochondrial ferritin; mitoferrins 1 and 2; ABCBs 6, 7, and 10; and frataxin) that may play roles in the homeostasis of mitochondrial iron. These mitochondrial proteins appear to participate in one or more processes of iron storage, iron uptake, and heme and iron-sulfur cluster synthesis. In this review, we present and critically discuss the evidence suggesting that the mitochondrion may contribute to the regulation of whole-cell iron metabolism. Further, human diseases that arise from a dysregulation of these mitochondrial molecules reveal the ability of the mitochondrion to communicate with cytosolic iron metabolism to coordinate whole-cell iron processing and to fulfill the high demands of this organelle for iron. This review highlights new advances in understanding iron metabolism in terms of novel molecular players and diseases associated with its dysregulation.
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Affiliation(s)
- Michael Li-Hsuan Huang
- Iron Metabolism and Chelation Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
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41
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Ohgari Y, Miyata Y, Miyagi T, Gotoh S, Ohta T, Kataoka T, Furuyama K, Taketani S. Roles of porphyrin and iron metabolisms in the δ-aminolevulinic acid (ALA)-induced accumulation of protoporphyrin and photodamage of tumor cells. Photochem Photobiol 2011; 87:1138-45. [PMID: 21668870 DOI: 10.1111/j.1751-1097.2011.00950.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
δ-Aminolevulinic acid (ALA)-induced porphyrin accumulation is widely used in the treatment of cancer, as photodynamic therapy. To clarify the mechanisms of the tumor-preferential accumulation of protoporphyrin, we examined the effect of the expression of heme-biosynthetic and -degradative enzymes on the ALA-induced accumulation of protoporphyrin as well as photodamage. The transient expression of heme-biosynthetic enzymes in HeLa cells caused variations of the ALA-induced accumulation of protoporphyrin. When ALA-treated cells were exposed to white light, the extent of photodamage of the cells was dependent on the accumulation of protoporphyrin. The decrease of the accumulation of protoporphyrin was observed in the cells treated with inducers of heme oxygenase (HO)-1. The ALA-dependent accumulation of protoporphyrin was decreased in HeLa cells by transfection with HO-1 and HO-2 cDNA. Conversely, knockdown of HO-1/-2 with siRNAs enhanced the ALA-induced protoporphyrin accumulation and photodamage. The ALA effect was decreased with HeLa cells expressing mitoferrin-2, a mitochondrial iron transporter, whereas it was enhanced by the mitoferrin-2 siRNA transfection. These results indicated that not only the production of porphyrin intermediates but also the reuse of iron from heme and mitochondrial iron utilization control the ALA-induced accumulation of protoporphyrin in cancerous cells.
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Affiliation(s)
- Yoshiko Ohgari
- Department of Biotechnology, Kyoto Institute of Technology, Kyoto, Japan
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42
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Maliandi MV, Busi MV, Turowski VR, Leaden L, Araya A, Gomez-Casati DF. The mitochondrial protein frataxin is essential for heme biosynthesis in plants. FEBS J 2010; 278:470-81. [DOI: 10.1111/j.1742-4658.2010.07968.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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43
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Gille G, Reichmann H. Iron-dependent functions of mitochondria--relation to neurodegeneration. J Neural Transm (Vienna) 2010; 118:349-59. [PMID: 21161302 DOI: 10.1007/s00702-010-0503-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 10/05/2010] [Indexed: 11/25/2022]
Abstract
A number of neurodegenerative diseases are associated with iron dyshomeostasis and mitochondrial dysfunction. However, the pathomechanistic interplay between iron and mitochondria varies. This review summarises the physiological role of iron in mitochondria and subsequently exemplifies two neurodegenerative diseases with disturbed iron function in mitochondria: inherited Friedreich ataxia (FRDA) and idiopathic Parkinson disease (PD). In eukaryotes, mitochondria are main consumers of iron. The respiratory chain relies on iron-containing redox systems in the form of complexes I-III with iron-sulphur clusters and cytochromes with haem as prosthetic groups. The bifunctional enzyme aconitase is not only important in the citric acid cycle, but also functions as a key regulator of cell iron metabolism. Haem biosynthesis occurs partially in mitochondria as well as the biogenesis of iron-sulphur clusters that are co-factors in numerous iron-sulphur proteins. FRDA is characterised by a mutation of the frataxin gene, the protein of which serves as an iron chaperone in iron-sulphur cluster assembly. The lack of frataxin expression leads to defective iron-sulphur cluster biogenesis with decreased respiratory and aconitase activity. The resulting mitochondrial iron overload might fuel reactive oxygen species formation and contribute to clinical signs of oxidative stress. PD is typically associated with an increased iron content of the substantia nigra, the causes of which are largely unknown. Recent research demonstrated raised iron levels in individual dopaminergic neurons of the substantia nigra. Moreover, transferrin/transferrin receptor 2 mediated transport of iron into the mitochondria of these neurons was identified together with increased transferrin immunoreactivity. Resulting accumulation of iron into mitochondria might lead to oxidative stress damaging iron-sulphur cluster-containing proteins.
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Affiliation(s)
- Gabriele Gille
- Klinik und Poliklinik für Neurologie, TU Dresden, Fetscherstr. 74, 01307, Dresden, Germany.
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44
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Cavallaro G. Genome-wide analysis of eukaryotic twin CX9C proteins. MOLECULAR BIOSYSTEMS 2010; 6:2459-70. [PMID: 20922212 DOI: 10.1039/c0mb00058b] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Twin CX(9)C proteins are eukaryotic proteins that derive their name from their characteristic motif, consisting of two pairs of cysteines that form two disulfide bonds stabilizing a coiled coil-helix-coiled coil-helix (CHCH) fold. The best characterized of these proteins are Cox17, a copper chaperone acting in cytochrome c oxidase biogenesis, and Mia40, the central component of a system for protein import into the mitochondrial inter-membrane space (IMS). However, the range of possible functions for these proteins is unclear. Here, we performed a systematic search of twin CX(9)C proteins in eukaryotic organisms, and classified them into groups of putative homologues, by combining bioinformatics methods with literature analysis. Our results suggest that the functions of most twin CX(9)C proteins vary around the common theme of playing a scaffolding role, which can tie their observed roles in mitochondrial structure and function. This study will enhance the present annotation of eukaryotic proteomes, and will provide a rational basis for future experimental work aimed at a deeper understanding of this remarkable class of proteins.
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Affiliation(s)
- Gabriele Cavallaro
- Magnetic Resonance Center (CERM)-University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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Santos R, Lefevre S, Sliwa D, Seguin A, Camadro JM, Lesuisse E. Friedreich ataxia: molecular mechanisms, redox considerations, and therapeutic opportunities. Antioxid Redox Signal 2010; 13:651-90. [PMID: 20156111 PMCID: PMC2924788 DOI: 10.1089/ars.2009.3015] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 02/08/2010] [Accepted: 02/14/2010] [Indexed: 12/14/2022]
Abstract
Mitochondrial dysfunction and oxidative damage are at the origin of numerous neurodegenerative diseases like Friedreich ataxia and Alzheimer and Parkinson diseases. Friedreich ataxia (FRDA) is the most common hereditary ataxia, with one individual affected in 50,000. This disease is characterized by progressive degeneration of the central and peripheral nervous systems, cardiomyopathy, and increased incidence of diabetes mellitus. FRDA is caused by a dynamic mutation, a GAA trinucleotide repeat expansion, in the first intron of the FXN gene. Fewer than 5% of the patients are heterozygous and carry point mutations in the other allele. The molecular consequences of the GAA triplet expansion is transcription silencing and reduced expression of the encoded mitochondrial protein, frataxin. The precise cellular role of frataxin is not known; however, it is clear now that several mitochondrial functions are not performed correctly in patient cells. The affected functions include respiration, iron-sulfur cluster assembly, iron homeostasis, and maintenance of the redox status. This review highlights the molecular mechanisms that underlie the disease phenotypes and the different hypothesis about the function of frataxin. In addition, we present an overview of the most recent therapeutic approaches for this severe disease that actually has no efficient treatment.
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Affiliation(s)
- Renata Santos
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Sophie Lefevre
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
- University Pierre et Marie Curie, Paris, France
| | - Dominika Sliwa
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Alexandra Seguin
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Jean-Michel Camadro
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
| | - Emmanuel Lesuisse
- Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod (UMR 7592 CNRS–University Paris-Diderot), Paris, France
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Erythropoiesis and iron sulfur cluster biogenesis. Adv Hematol 2010; 2010. [PMID: 20862391 PMCID: PMC2939393 DOI: 10.1155/2010/329394] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 06/04/2010] [Accepted: 08/02/2010] [Indexed: 11/22/2022] Open
Abstract
Erythropoiesis in animals is a synchronized process of erythroid cell differentiation that depends on successful acquisition of iron. Heme synthesis depends on iron through its dependence on iron sulfur (Fe-S) cluster biogenesis. Here, we review the relationship between Fe-S biogenesis and heme synthesis in erythropoiesis, with emphasis on the proteins, GLRX5, ABCB7, ISCA, and C1orf69. These Fe-S biosynthesis proteins are highly expressed in erythroid tissues, and deficiency of each of these proteins has been shown to cause anemia in zebrafish model. GLRX5 is involved in the production and ABCB7 in the export of an unknown factor that may function as a gauge of mitochondrial iron status, which may indirectly modulate activity of iron regulatory proteins (IRPs). ALAS2, the enzyme catalyzing the first step in heme synthesis, is translationally controlled by IRPs. GLRX5 may also provide Fe-S cofactor for ferrochelatase, the last enzyme in heme synthesis. ISCA and C1orf69 are thought to assemble Fe-S clusters for mitochondrial aconitase and for lipoate synthase, the enzyme producing lipoate for pyruvate dehydrogenase complex (PDC). PDC and aconitase are involved in the production of succinyl-CoA, a substrate for heme biosynthesis. Thus, many steps of heme synthesis depend on Fe-S cluster assembly.
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Richardson DR, Huang MLH, Whitnall M, Becker EM, Ponka P, Suryo Rahmanto Y. The ins and outs of mitochondrial iron-loading: the metabolic defect in Friedreich's ataxia. J Mol Med (Berl) 2010; 88:323-9. [PMID: 19997898 DOI: 10.1007/s00109-009-0565-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 10/23/2009] [Accepted: 11/13/2009] [Indexed: 01/21/2023]
Abstract
Friedreich's ataxia is a cardio- and neurodegenerative disease due to decreased expression of the mitochondrial protein, frataxin. This defect results in mitochondrial iron-overload, and in this review, we discuss the mechanisms that lead to this iron accumulation. Using a conditional knockout mouse model where frataxin is deleted in the heart, it has been shown that this mutation leads to transferrin receptor-1 upregulation, resulting in increased iron uptake from transferrin. There is also marked downregulation of ferritin that is required for iron storage and decreased expression of the iron exporter, ferroportin 1, leading to decreased cellular iron efflux. The increased mitochondrial iron uptake is facilitated by upregulation of the mitochondrial iron transporter, mitoferrin 2. This stimulation of iron uptake probably attempts to rescue the deficit in mitochondrial iron metabolism that is due to downregulation of mitochondrial iron utilization, namely, heme and iron-sulfur cluster (ISC) synthesis and also iron storage (mitochondrial ferritin). The resultant decrease in heme and ISC synthesis means heme and ISCs are not exiting the mitochondrion for cytosolic use. Hence, increased mitochondrial iron uptake coupled with decreased utilization and release leads to mitochondrial iron-loading. More generally, disturbance of mitochondrial iron utilization in other diseases probably also results in similar compensatory alterations.
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Affiliation(s)
- Des R Richardson
- Iron Metabolism and Chelation Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, NSW, 2006, Australia.
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Johnstone D, Milward EA. Molecular genetic approaches to understanding the roles and regulation of iron in brain health and disease. J Neurochem 2010; 113:1387-402. [PMID: 20345752 DOI: 10.1111/j.1471-4159.2010.06697.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Iron is essential in the brain, yet too much iron can be toxic. Tight regulation of iron in the brain may involve intrinsic mechanisms that control internal homeostasis independent of systemic iron status. Iron abnormalities occur in various neurological disorders, usually with symptoms or neuropathology associated with movement impairment or behavioral disturbances rather than cognitive impairment or dementia. Consistent with this, polymorphisms in the HFE gene, associated with the iron overload disorder hemochromatosis, show stronger associations with the movement disorder amyotrophic lateral sclerosis (motor neuron disease) than with cognitive impairment. Such associations may arise because certain brain regions involved in movement or executive control are particularly iron-rich, notably the basal ganglia, and may be highly reliant on iron. Various mechanisms, including iron redistribution causing functional iron deficiency, lysosomal and mitochondrial abnormalities or oxidative damage, could underlie iron-related neuropathogenesis. Clarifying how iron contributes causatively to neurodegeneration may improve treatment options in a range of neurodegenerative disorders. This review considers how modern molecular genetic approaches can be applied to resolve the complex molecular systems and pathways by which brain iron homeostasis is regulated and the molecular changes that occur with iron dyshomeostasis and neuropathogenesis.
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Affiliation(s)
- Daniel Johnstone
- School of Biomedical Sciences and Pharmacy and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia
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Marmolino D, Manto M. Past, present and future therapeutics for cerebellar ataxias. Curr Neuropharmacol 2010; 8:41-61. [PMID: 20808545 PMCID: PMC2866461 DOI: 10.2174/157015910790909476] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 11/18/2009] [Accepted: 11/30/2009] [Indexed: 01/14/2023] Open
Abstract
Cerebellar ataxias are a group of disabling neurological disorders. Patients exhibit a cerebellar syndrome and can also present with extra-cerebellar deficits, namely pigmentary retinopathy, extrapyramidal movement disorders, pyramidal signs, cortical symptoms (seizures, cognitive impairment/behavioural symptoms), and peripheral neuropathy. Recently, deficits in cognitive operations have been unraveled. Cerebellar ataxias are heterogeneous both at the phenotypic and genotypic point of view. Therapeutical trials performed during these last 4 decades have failed in most cases, in particular because drugs were not targeting a deleterious pathway, but were given to counteract putative defects in neurotransmission. The identification of the causative mutations of many hereditary ataxias, the development of relevant animal models and the recent identifications of the molecular mechanisms underlying ataxias are impacting on the development of new drugs. We provide an overview of the pharmacological treatments currently used in the clinical practice and we discuss the drugs under development.
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Affiliation(s)
- D Marmolino
- Laboratoire de Neurologie Expèrimentale ULB-Erasme, Brussels, Belgium.
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Haugen AC, Di Prospero NA, Parker JS, Fannin RD, Chou J, Meyer JN, Halweg C, Collins JB, Durr A, Fischbeck K, Van Houten B. Altered gene expression and DNA damage in peripheral blood cells from Friedreich's ataxia patients: cellular model of pathology. PLoS Genet 2010; 6:e1000812. [PMID: 20090835 PMCID: PMC2799513 DOI: 10.1371/journal.pgen.1000812] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 12/10/2009] [Indexed: 12/02/2022] Open
Abstract
The neurodegenerative disease Friedreich's ataxia (FRDA) is the most common autosomal-recessively inherited ataxia and is caused by a GAA triplet repeat expansion in the first intron of the frataxin gene. In this disease, transcription of frataxin, a mitochondrial protein involved in iron homeostasis, is impaired, resulting in a significant reduction in mRNA and protein levels. Global gene expression analysis was performed in peripheral blood samples from FRDA patients as compared to controls, which suggested altered expression patterns pertaining to genotoxic stress. We then confirmed the presence of genotoxic DNA damage by using a gene-specific quantitative PCR assay and discovered an increase in both mitochondrial and nuclear DNA damage in the blood of these patients (p<0.0001, respectively). Additionally, frataxin mRNA levels correlated with age of onset of disease and displayed unique sets of gene alterations involved in immune response, oxidative phosphorylation, and protein synthesis. Many of the key pathways observed by transcription profiling were downregulated, and we believe these data suggest that patients with prolonged frataxin deficiency undergo a systemic survival response to chronic genotoxic stress and consequent DNA damage detectable in blood. In conclusion, our results yield insight into the nature and progression of FRDA, as well as possible therapeutic approaches. Furthermore, the identification of potential biomarkers, including the DNA damage found in peripheral blood, may have predictive value in future clinical trials.
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Affiliation(s)
- Astrid C. Haugen
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Nicholas A. Di Prospero
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Joel S. Parker
- Expression Analysis, Durham, North Carolina, United States of America
| | - Rick D. Fannin
- Laboratory of Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Jeff Chou
- Laboratory of Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Joel N. Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Christopher Halweg
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Jennifer B. Collins
- Laboratory of Toxicogenomics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, United States of America
| | - Alexandra Durr
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Université Pierre et Marie Curie, Paris, France
- Département de Génétique et Embryologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - Kenneth Fischbeck
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States of America
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- University of Pittsburgh Cancer Institute, Hillman Cancer Center, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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