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Wu L, Huang F, Yang L, Yang L, Sun Z, Zhang J, Xia S, Zhao H, Ding Y, Bian D, Li K. Interplay of FXN expression and lipolysis in white adipocytes plays a critical role in insulin sensitivity in Friedreich's ataxia mouse model. Sci Rep 2024; 14:19876. [PMID: 39191875 DOI: 10.1038/s41598-024-71099-7] [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: 06/12/2024] [Accepted: 08/23/2024] [Indexed: 08/29/2024] Open
Abstract
Frataxin (FXN) is required for iron-sulfur cluster biogenesis, and its loss causes the early-onset neurodegenerative disease Friedreich ataxia (FRDA). Loss of FXN is a susceptibility factor in the development of diabetes, a common metabolic complication after myocardial hypertrophy in patients with FRDA. The underlying mechanism of FXN deficient-induced hyperglycemia in FRDA is, however, poorly understood. In this study, we confirmed that the FXN deficiency mouse model YG8R develops insulin resistance in elder individuals by disturbing lipid metabolic homeostasis in adipose tissues. Evaluation of lipolysis, lipogenesis, and fatty acid β-oxidation showed that lipolysis is most severely affected in white adipose tissues. Consistently, FXN deficiency significantly decreased expression of lipolytic genes encoding adipose triglyceride lipase (Atgl) and hormone-sensitive lipase (Hsl) resulting in adipocyte enlargement and inflammation. Lipolysis induction by fasting or cold exposure remarkably upregulated FXN expression, though FXN deficiency lessened the competency of lipolysis compared with the control or wild type mice. Moreover, we found that the impairment of lipolysis was present at a young age, a few months earlier than hyperglycemia and insulin resistance. Forskolin, an activator of lipolysis, or pioglitazone, an agonist of PPARγ, improved insulin sensitivity in FXN-deficient adipocytes or mice. We uncovered the interplay between FXN expression and lipolysis and found that impairment of lipolysis, particularly the white adipocytes, is an early event, likely, as a primary cause for insulin resistance in FRDA patients at later age.
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Affiliation(s)
- Lin Wu
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Fei Huang
- Endocrinology Department, Yancheng First People's Hospital, Affiliated Hospital of Medical School, Nanjing University, Yancheng, 224000, People's Republic of China
| | - Lu Yang
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Liu Yang
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Zichen Sun
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Jinghua Zhang
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Siyu Xia
- Endocrinology Department, Yancheng First People's Hospital, Affiliated Hospital of Medical School, Nanjing University, Yancheng, 224000, People's Republic of China
| | - Hongting Zhao
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Yibing Ding
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Dezhi Bian
- Endocrinology Department, Yancheng First People's Hospital, Affiliated Hospital of Medical School, Nanjing University, Yancheng, 224000, People's Republic of China.
| | - Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, 210093, People's Republic of China.
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Gnimpieba E, Diing DM, Ailts J, Cucak A, Gakh O, Isaya G, Vitiello S, Wang S, Pierce P, Cooper A, Roux K, Rogers LK, Vitiello PF. Mapping Novel Frataxin Mitochondrial Networks Through Protein- Protein Interactions. RESEARCH SQUARE 2024:rs.3.rs-4259413. [PMID: 38746130 PMCID: PMC11092868 DOI: 10.21203/rs.3.rs-4259413/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Friedreich's Ataxia (FRDA) is a neuromuscular degenerative disorder caused by trinucleotide expansions in the first intron of the frataxin (FXN) gene, resulting in insufficient levels of functional FNX protein. Deficits in FXN involve mitochondrial disruptions including iron-sulfur cluster synthesis and impaired energetics. These studies were to identify unique protein-protein interactions with FXN to better understand its function and design therapeutics. Two complementary approaches were employed, BioID and Co-IP, to identify protein interactions with FXN at the direct binding, indirect binding, and non-proximal levels. Forty-one novel protein interactions were identified by BioID and IP techniques. The FXN protein landscape was further analyzed incorporating both interaction type and functional pathways using a maximum path of 6 proteins with a potential direct interaction between FXN and NFS1. Probing the intersection between FXN-protein landscape and biological pathways associated with FRDA, we identified 41 proteins of interest. Peroxiredoxin 3 (Prdx3) was chosen for further analysis because of its role in mitochondrial oxidative injury. Our data has demonstrated the strengths of employing complementary methods to identify a unique interactome for FXN. Our data provides new insights into FXN function and regulation, a potential direct interaction between FXN and NFS1, and pathway interactions between FXN and Prdx3.
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Affiliation(s)
| | | | - Jared Ailts
- University of South Dakota Sanford School of Medicine
| | | | | | | | | | | | - Paul Pierce
- University of Oklahoma Health Sciences Center
| | - Alec Cooper
- University of Oklahoma Health Sciences Center
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Averina OA, Kuznetsova SA, Permyakov OA, Sergiev PV. Animal Models of Mitochondrial Diseases Associated with Nuclear Gene Mutations. Acta Naturae 2023; 15:4-22. [PMID: 38234606 PMCID: PMC10790356 DOI: 10.32607/actanaturae.25442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 10/05/2023] [Indexed: 01/19/2024] Open
Abstract
Mitochondrial diseases (MDs) associated with nuclear gene mutations are part of a large group of inherited diseases caused by the suppression of energy metabolism. These diseases are of particular interest, because nuclear genes encode not only most of the structural proteins of the oxidative phosphorylation system (OXPHOS), but also all the proteins involved in the OXPHOS protein import from the cytoplasm and their assembly in mitochondria. Defects in any of these proteins can lead to functional impairment of the respiratory chain, including dysfunction of complex I that plays a central role in cellular respiration and oxidative phosphorylation, which is the most common cause of mitopathologies. Mitochondrial diseases are characterized by an early age of onset and a progressive course and affect primarily energy-consuming tissues and organs. The treatment of MDs should be initiated as soon as possible, but the diagnosis of mitopathologies is extremely difficult because of their heterogeneity and overlapping clinical features. The molecular pathogenesis of mitochondrial diseases is investigated using animal models: i.e. animals carrying mutations causing MD symptoms in humans. The use of mutant animal models opens new opportunities in the study of genes encoding mitochondrial proteins, as well as the molecular mechanisms of mitopathology development, which is necessary for improving diagnosis and developing approaches to drug therapy. In this review, we present the most recent information on mitochondrial diseases associated with nuclear gene mutations and animal models developed to investigate them.
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Affiliation(s)
- O. A. Averina
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - S. A. Kuznetsova
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - O. A. Permyakov
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - P. V. Sergiev
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
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Slobodian MR, Petahtegoose JD, Wallis AL, Levesque DC, Merritt TJS. The Effects of Essential and Non-Essential Metal Toxicity in the Drosophila melanogaster Insect Model: A Review. TOXICS 2021; 9:269. [PMID: 34678965 PMCID: PMC8540122 DOI: 10.3390/toxics9100269] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 02/07/2023]
Abstract
The biological effects of environmental metal contamination are important issues in an industrialized, resource-dependent world. Different metals have different roles in biology and can be classified as essential if they are required by a living organism (e.g., as cofactors), or as non-essential metals if they are not. While essential metal ions have been well studied in many eukaryotic species, less is known about the effects of non-essential metals, even though essential and non-essential metals are often chemically similar and can bind to the same biological ligands. Insects are often exposed to a variety of contaminated environments and associated essential and non-essential metal toxicity, but many questions regarding their response to toxicity remain unanswered. Drosophila melanogaster is an excellent insect model species in which to study the effects of toxic metal due to the extensive experimental and genetic resources available for this species. Here, we review the current understanding of the impact of a suite of essential and non-essential metals (Cu, Fe, Zn, Hg, Pb, Cd, and Ni) on the D. melanogaster metal response system, highlighting the knowledge gaps between essential and non-essential metals in D. melanogaster. This review emphasizes the need to use multiple metals, multiple genetic backgrounds, and both sexes in future studies to help guide future research towards better understanding the effects of metal contamination in general.
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Affiliation(s)
| | | | | | | | - Thomas J. S. Merritt
- Faculty of Science and Engineering, Laurentian University, 935 Ramsey Lake Rd, Sudbury, ON P3E 2C6, Canada; (M.R.S.); (J.D.P.); (A.L.W.); (D.C.L.)
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Petrillo S, Santoro M, La Rosa P, Perna A, Gallo MG, Bertini ES, Silvestri G, Piemonte F. Nuclear Factor Erythroid 2-Related Factor 2 Activation Might Mitigate Clinical Symptoms in Friedreich's Ataxia: Clues of an "Out-Brain Origin" of the Disease From a Family Study. Front Neurosci 2021; 15:638810. [PMID: 33708070 PMCID: PMC7940825 DOI: 10.3389/fnins.2021.638810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/22/2021] [Indexed: 11/25/2022] Open
Abstract
Friedreich’s ataxia (FRDA) is the most frequent autosomal recessive ataxia in western countries, with a mean age of onset at 10–15 years. Patients manifest progressive cerebellar and sensory ataxia, dysarthria, lower limb pyramidal weakness, and other systemic manifestations. Previously, we described a family displaying two expanded GAA alleles not only in the proband affected by late-onset FRDA but also in the two asymptomatic family members: the mother and the younger sister. Both of them showed a significant reduction of frataxin levels, without any disease manifestation. Here, we analyzed if a protective mechanism might contribute to modulate the phenotype in this family. We particularly focused on the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), the first line of antioxidant defense in cells, and on the glutathione (GSH) system, an index of reactive oxygen species (ROS) detoxification ability. Our findings show a great reactivity of the GSH system to the frataxin deficiency, particularly in the asymptomatic mother, where the genes of GSH synthesis [glutamate–cysteine ligase (GCL)] and GSSG detoxification [GSH S-reductase (GSR)] were highly responsive. The GSR was activated even in the asymptomatic sister and in the proband, reflecting the need of buffering the GSSG increase. Furthermore, and contrasting the NRF2 expression documented in FRDA tissues, NRF2 was highly activated in the mother and in the younger sister, while it was constitutively low in the proband. This suggests that, also under frataxin depletion, the endogenous stimulation of NRF2 in asymptomatic FRDA subjects may contribute to protect against the progressive oxidative damage, helping to prevent the onset of neurological symptoms and highlighting an “out-brain origin” of the disease.
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Affiliation(s)
- Sara Petrillo
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | - Piergiorgio La Rosa
- Division of Neuroscience, Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Alessia Perna
- Department of Neurosciences, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Maria Giovanna Gallo
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Gabriella Silvestri
- Department of Neurosciences, Università Cattolica del Sacro Cuore, Rome, Italy.,UOC of Neurology, Area of Neuroscience, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Fiorella Piemonte
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
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Phang MWL, Lew SY, Chung I, Lim WKS, Lim LW, Wong KH. Therapeutic roles of natural remedies in combating hereditary ataxia: A systematic review. Chin Med 2021; 16:15. [PMID: 33509239 PMCID: PMC7841890 DOI: 10.1186/s13020-020-00414-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/17/2020] [Accepted: 12/11/2020] [Indexed: 12/30/2022] Open
Abstract
Background Hereditary ataxia (HA) represents a group of genetically heterogeneous neurodegenerative diseases caused by dysfunction of the cerebellum or disruption of the connection between the cerebellum and other areas of the central nervous system. Phenotypic manifestation of HA includes unsteadiness of stance and gait, dysarthria, nystagmus, dysmetria and complaints of clumsiness. There are no specific treatments for HA. Management strategies provide supportive treatment to reduce symptoms. Objectives This systematic review aimed to identify, evaluate and summarise the published literature on the therapeutic roles of natural remedies in the treatment of HA to provide evidence for clinical practice. Methods A systematic literature search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Web of Science, PubMed and Science Direct Scopus were thoroughly searched for relevant published articles from June 2007 to July 2020. Results Ten pre-clinical and two clinical studies were eligible for inclusion in this systematic review. We identified the therapeutic roles of medicinal plants Brassica napus, Gardenia jasminoides, Gastrodia elata, Ginkgo biloba, Glycyrrhiza inflata, Paeonia lactiflora, Pueraria lobata and Rehmannia glutinosa; herbal formulations Shaoyao Gancao Tang and Zhengan Xifeng Tang; and medicinal mushroom Hericium erinaceus in the treatment of HA. In this review, we evaluated the mode of actions contributing to their therapeutic effects, including activation of the ubiquitin–proteasome system, activation of antioxidant pathways, maintenance of intracellular calcium homeostasis and regulation of chaperones. We also briefly highlighted the integral cellular signalling pathways responsible for orchestrating the mode of actions. Conclusion We reviewed the therapeutic roles of natural remedies in improving or halting the progression of HA, which warrant further study for applications into clinical practice.
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Affiliation(s)
- Michael Weng Lok Phang
- Department of Anatomy, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Sze Yuen Lew
- Department of Anatomy, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Ivy Chung
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - William Kiong-Seng Lim
- Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kuching, Sarawak, 94300, Malaysia
| | - Lee Wei Lim
- Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, China.
| | - Kah Hui Wong
- Department of Anatomy, Faculty of Medicine, University of Malaya, Kuala Lumpur, 50603, Malaysia.
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Kahroba H, Ramezani B, Maadi H, Sadeghi MR, Jaberie H, Ramezani F. The role of Nrf2 in neural stem/progenitors cells: From maintaining stemness and self-renewal to promoting differentiation capability and facilitating therapeutic application in neurodegenerative disease. Ageing Res Rev 2021; 65:101211. [PMID: 33186670 DOI: 10.1016/j.arr.2020.101211] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/05/2020] [Accepted: 11/07/2020] [Indexed: 02/07/2023]
Abstract
Neurodegenerative diseases (NDs) cause progressive loss of neurons in nervous system. NDs are categorized as acute NDs such as stroke and head injury, besides chronic NDs including Alzheimer's, Parkinson's, Huntington's diseases, Friedreich's Ataxia, Multiple Sclerosis. The exact etiology of NDs is not understood but oxidative stress, inflammation and synaptic dysfunction are main hallmarks. Oxidative stress leads to free radical attack on neural cells which contributes to protein misfolding, glia cell activation, mitochondrial dysfunction, impairment of DNA repair system and subsequently cellular death. Neural stem cells (NSCs) support adult neurogenesis in nervous system during injuries which is limited to certain regions in brain. NSCs can differentiate into the neurons, astrocytes or oligodendrocytes. Impaired neurogenesis and inadequate induction of neurogenesis are the main obstacles in treatment of NDs. Protection of neural cells from oxidative damages and supporting neurogenesis are promising strategies to treat NDs. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional master regulator that maintains the redox homeostasis in cells by provoking expression of antioxidant, anti-inflammatory and cytoprotective genes. Nrf2 can strongly influence the NSCs function and fate determination by reducing levels of reactive oxygen species in benefit of NSC survival and neurogenesis. In this review we will summarize the role of Nrf2 in NSC function, and exogenous and endogenous therapeutic strategies in treatment of NDs.
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Affiliation(s)
- Houman Kahroba
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Bahman Ramezani
- Department of Chemistry, Tabriz Branch, Islamic Azad University, Tabriz, Iran
| | - Hamid Maadi
- Department of Medical Genetics, and Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Mohammad Reza Sadeghi
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hajar Jaberie
- Department of Biochemistry, Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Fatemeh Ramezani
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
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La Rosa P, Petrillo S, Fiorenza MT, Bertini ES, Piemonte F. Ferroptosis in Friedreich's Ataxia: A Metal-Induced Neurodegenerative Disease. Biomolecules 2020; 10:biom10111551. [PMID: 33202971 PMCID: PMC7696618 DOI: 10.3390/biom10111551] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 02/07/2023] Open
Abstract
Ferroptosis is an iron-dependent form of regulated cell death, arising from the accumulation of lipid-based reactive oxygen species when glutathione-dependent repair systems are compromised. Lipid peroxidation, mitochondrial impairment and iron dyshomeostasis are the hallmark of ferroptosis, which is emerging as a crucial player in neurodegeneration. This review provides an analysis of the most recent advances in ferroptosis, with a special focus on Friedreich's Ataxia (FA), the most common autosomal recessive neurodegenerative disease, caused by reduced levels of frataxin, a mitochondrial protein involved in iron-sulfur cluster synthesis and antioxidant defenses. The hypothesis is that the iron-induced oxidative damage accumulates over time in FA, lowering the ferroptosis threshold and leading to neuronal cell death and, at last, to cardiac failure. The use of anti-ferroptosis drugs combined with treatments able to activate the antioxidant response will be of paramount importance in FA therapy, such as in many other neurodegenerative diseases triggered by oxidative stress.
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Affiliation(s)
- Piergiorgio La Rosa
- Department of Psychology, Division of Neuroscience, Sapienza University of Rome, 00185 Rome, Italy; (P.L.R.); (M.T.F.)
| | - Sara Petrillo
- Unit of Muscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (S.P.); (E.S.B.)
| | - Maria Teresa Fiorenza
- Department of Psychology, Division of Neuroscience, Sapienza University of Rome, 00185 Rome, Italy; (P.L.R.); (M.T.F.)
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (S.P.); (E.S.B.)
| | - Fiorella Piemonte
- Unit of Muscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (S.P.); (E.S.B.)
- Correspondence: ; Tel.: +39-06-6859-2102
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Catapano MC, Protti M, Fontana T, Mandrioli R, Mladěnka P, Mercolini L. An Original HPLC Method with Coulometric Detection to Monitor Hydroxyl Radical Generation via Fenton Chemistry. Molecules 2019; 24:molecules24173066. [PMID: 31450723 PMCID: PMC6749383 DOI: 10.3390/molecules24173066] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 12/28/2022] Open
Abstract
Hydroxyl radicals (•OH) can be generated via Fenton chemistry catalyzed by transition metals. An in vitro Fenton system was developed to test both the inhibition and stimulation of •OH formation, by monitoring salicylate aromatic hydroxylation derivatives as markers of •OH production. The reaction was optimized with either iron or copper, and target analytes were determined by means of an original HPLC method coupled to coulometric detection. The method granted good sensitivity and precision, while method applicability was tested on antioxidant compounds with and without chelating properties in different substance to metal ratios. This analytical approach shows how Fenton's reaction can be monitored by HPLC coupled to coulometric detection, as a powerful tool for studying molecules' redox behavior.
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Affiliation(s)
- Maria Carmen Catapano
- Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum-University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Michele Protti
- Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum-University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy.
| | - Tommaso Fontana
- Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum-University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
| | - Roberto Mandrioli
- Department for Life Quality Studies (QuVi), Alma Mater Studiorum-University of Bologna, Corso d'Augusto 237, 47921 Rimini, Italy
| | - Přemysl Mladěnka
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Laura Mercolini
- Department of Pharmacy and Biotechnology (FaBiT), Alma Mater Studiorum-University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy
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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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11
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Deal SL, Yamamoto S. Unraveling Novel Mechanisms of Neurodegeneration Through a Large-Scale Forward Genetic Screen in Drosophila. Front Genet 2019; 9:700. [PMID: 30693015 PMCID: PMC6339878 DOI: 10.3389/fgene.2018.00700] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 12/13/2018] [Indexed: 01/04/2023] Open
Abstract
Neurodegeneration is characterized by progressive loss of neurons. Genetic and environmental factors both contribute to demise of neurons, leading to diverse devastating cognitive and motor disorders, including Alzheimer's and Parkinson's diseases in humans. Over the past few decades, the fruit fly, Drosophila melanogaster, has become an integral tool to understand the molecular, cellular and genetic mechanisms underlying neurodegeneration. Extensive tools and sophisticated technologies allow Drosophila geneticists to identify and study evolutionarily conserved genes that are essential for neural maintenance. In this review, we will focus on a large-scale mosaic forward genetic screen on the fly X-chromosome that led to the identification of a number of essential genes that exhibit neurodegenerative phenotypes when mutated. Most genes identified from this screen are evolutionarily conserved and many have been linked to human diseases with neurological presentations. Systematic electrophysiological and ultrastructural characterization of mutant tissue in the context of the Drosophila visual system, followed by a series of experiments to understand the mechanism of neurodegeneration in each mutant led to the discovery of novel molecular pathways that are required for neuronal integrity. Defects in mitochondrial function, lipid and iron metabolism, protein trafficking and autophagy are recurrent themes, suggesting that insults that eventually lead to neurodegeneration may converge on a set of evolutionarily conserved cellular processes. Insights from these studies have contributed to our understanding of known neurodegenerative diseases such as Leigh syndrome and Friedreich's ataxia and have also led to the identification of new human diseases. By discovering new genes required for neural maintenance in flies and working with clinicians to identify patients with deleterious variants in the orthologous human genes, Drosophila biologists can play an active role in personalized medicine.
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Affiliation(s)
- Samantha L Deal
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, United States
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12
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Abstract
Friedreich's ataxia (FRDA) is a degenerative disease that affects both the central and the peripheral nervous systems and non-neural tissues including, mainly, heart, and endocrine pancreas. It is an autosomal recessive disease caused by a GAA triplet-repeat localized within an Alu sequence element in intron 1 of frataxin (FXN) gene, which encodes a mitochondrial protein FXN. This protein is essential for mitochondrial function by the involvement of iron-sulfur cluster biogenesis. The effects of its deficiency also include disruption of cellular, particularly mitochondrial, iron homeostasis, i.e., relatively more iron accumulated in mitochondria and less iron presented in cytosol. Though iron toxicity is commonly thought to be mediated via Fenton reaction, oxidative stress seems not to be the main problem to result in detrimental effects on cell survival, particularly neuron survival. Therefore, the basic research on FXN function is urgently demanded to understand the disease. This chapter focuses on the outcome of FXN expression, regulation, and function in cellular or animal models of FRDA and on iron pathophysiology in the affected tissues. Finally, therapeutic strategies based on the control of iron toxicity and iron cellular redistribution are considered. The combination of multiple therapeutic targets including iron, oxidative stress, mitochondrial function, and FXN regulation is also proposed.
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Affiliation(s)
- Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, 210093, People's Republic of China.
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13
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Role of frataxin protein deficiency and metabolic dysfunction in Friedreich ataxia, an autosomal recessive mitochondrial disease. Neuronal Signal 2018; 2:NS20180060. [PMID: 32714592 PMCID: PMC7373238 DOI: 10.1042/ns20180060] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 01/04/2023] Open
Abstract
Friedreich ataxia (FRDA) is a progressive neurodegenerative disease with developmental features caused by a genetic deficiency of frataxin, a small, nuclear-encoded mitochondrial protein. Frataxin deficiency leads to impairment of iron–sulphur cluster synthesis, and consequently, ATP production abnormalities. Based on the involvement of such processes in FRDA, initial pathophysiological hypotheses focused on reactive oxygen species (ROS) production as a key component of the mechanism. With further study, a variety of other events appear to be involved, including abnormalities of mitochondrially related metabolism and dysfunction in mitochondrial biogenesis. Consequently, present therapies focus not only on free radical damage, but also on control of metabolic abnormalities and correction of mitochondrial biogenesis. Understanding the multitude of abnormalities in FRDA thus offers possibilities for treatment of this disorder.
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14
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Alsina D, Purroy R, Ros J, Tamarit J. Iron in Friedreich Ataxia: A Central Role in the Pathophysiology or an Epiphenomenon? Pharmaceuticals (Basel) 2018; 11:E89. [PMID: 30235822 PMCID: PMC6161073 DOI: 10.3390/ph11030089] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 12/16/2022] Open
Abstract
Friedreich ataxia is a neurodegenerative disease with an autosomal recessive inheritance. In most patients, the disease is caused by the presence of trinucleotide GAA expansions in the first intron of the frataxin gene. These expansions cause the decreased expression of this mitochondrial protein. Many evidences indicate that frataxin deficiency causes the deregulation of cellular iron homeostasis. In this review, we will discuss several hypotheses proposed for frataxin function, their caveats, and how they could provide an explanation for the deregulation of iron homeostasis found in frataxin-deficient cells. We will also focus on the potential mechanisms causing cellular dysfunction in Friedreich Ataxia and on the potential use of the iron chelator deferiprone as a therapeutic agent for this disease.
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Affiliation(s)
- David Alsina
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
| | - Rosa Purroy
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
| | - Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25198 Lleida, Spain.
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15
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Palandri A, Martin E, Russi M, Rera M, Tricoire H, Monnier V. Identification of cardioprotective drugs by medium-scale in vivo pharmacological screening on a Drosophila cardiac model of Friedreich's ataxia. Dis Model Mech 2018; 11:dmm033811. [PMID: 29898895 PMCID: PMC6078405 DOI: 10.1242/dmm.033811] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/06/2018] [Indexed: 12/30/2022] Open
Abstract
Friedreich's ataxia (FA) is caused by reduced levels of frataxin, a highly conserved mitochondrial protein. There is currently no effective treatment for this disease, which is characterized by progressive neurodegeneration and cardiomyopathy, the latter being the most common cause of death in patients. We previously developed a Drosophila melanogaster cardiac model of FA, in which the fly frataxin is inactivated specifically in the heart, leading to heart dilatation and impaired systolic function. Methylene Blue (MB) was highly efficient to prevent these cardiac dysfunctions. Here, we used this model to screen in vivo the Prestwick Chemical Library, comprising 1280 compounds. Eleven drugs significantly reduced the cardiac dilatation, some of which may possibly lead to therapeutic applications in the future. The one with the strongest protective effects was paclitaxel, a microtubule-stabilizing drug. In parallel, we characterized the histological defects induced by frataxin deficiency in cardiomyocytes and observed strong sarcomere alterations with loss of striation of actin fibers, along with full disruption of the microtubule network. Paclitaxel and MB both improved these structural defects. Therefore, we propose that frataxin inactivation induces cardiac dysfunction through impaired sarcomere assembly or renewal due to microtubule destabilization, without excluding additional mechanisms. This study is the first drug screening of this extent performed in vivo on a Drosophila model of cardiac disease. Thus, it also brings the proof of concept that cardiac functional imaging in adult Drosophila flies is usable for medium-scale in vivo pharmacological screening, with potent identification of cardioprotective drugs in various contexts of cardiac diseases.
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Affiliation(s)
- Amandine Palandri
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) UMR8251 CNRS, 75205, Paris Cedex 13, France
| | - Elodie Martin
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) UMR8251 CNRS, 75205, Paris Cedex 13, France
| | - Maria Russi
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) UMR8251 CNRS, 75205, Paris Cedex 13, France
| | - Michael Rera
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) UMR8251 CNRS, 75205, Paris Cedex 13, France
| | - Hervé Tricoire
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) UMR8251 CNRS, 75205, Paris Cedex 13, France
| | - Véronique Monnier
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) UMR8251 CNRS, 75205, Paris Cedex 13, France
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16
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Monnier V, Llorens JV, Navarro JA. Impact of Drosophila Models in the Study and Treatment of Friedreich's Ataxia. Int J Mol Sci 2018; 19:E1989. [PMID: 29986523 PMCID: PMC6073496 DOI: 10.3390/ijms19071989] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 06/26/2018] [Accepted: 07/03/2018] [Indexed: 02/07/2023] Open
Abstract
Drosophila melanogaster has been for over a century the model of choice of several neurobiologists to decipher the formation and development of the nervous system as well as to mirror the pathophysiological conditions of many human neurodegenerative diseases. The rare disease Friedreich’s ataxia (FRDA) is not an exception. Since the isolation of the responsible gene more than two decades ago, the analysis of the fly orthologue has proven to be an excellent avenue to understand the development and progression of the disease, to unravel pivotal mechanisms underpinning the pathology and to identify genes and molecules that might well be either disease biomarkers or promising targets for therapeutic interventions. In this review, we aim to summarize the collection of findings provided by the Drosophila models but also to go one step beyond and propose the implications of these discoveries for the study and cure of this disorder. We will present the physiological, cellular and molecular phenotypes described in the fly, highlighting those that have given insight into the pathology and we will show how the ability of Drosophila to perform genetic and pharmacological screens has provided valuable information that is not easily within reach of other cellular or mammalian models.
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Affiliation(s)
- Véronique Monnier
- Unité de Biologie Fonctionnelle et Adaptative (BFA), Sorbonne Paris Cité, Université Paris Diderot, UMR8251 CNRS, 75013 Paris, France.
| | - Jose Vicente Llorens
- Department of Genetics, University of Valencia, Campus of Burjassot, 96100 Valencia, Spain.
| | - Juan Antonio Navarro
- Lehrstuhl für Entwicklungsbiologie, Universität Regensburg, 93040 Regensburg, Germany.
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17
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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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18
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Calap-Quintana P, Navarro JA, González-Fernández J, Martínez-Sebastián MJ, Moltó MD, Llorens JV. Drosophila melanogaster Models of Friedreich's Ataxia. BIOMED RESEARCH INTERNATIONAL 2018; 2018:5065190. [PMID: 29850527 PMCID: PMC5907503 DOI: 10.1155/2018/5065190] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 01/29/2018] [Accepted: 02/28/2018] [Indexed: 11/17/2022]
Abstract
Friedreich's ataxia (FRDA) is a rare inherited recessive disorder affecting the central and peripheral nervous systems and other extraneural organs such as the heart and pancreas. This incapacitating condition usually manifests in childhood or adolescence, exhibits an irreversible progression that confines the patient to a wheelchair, and leads to early death. FRDA is caused by a reduced level of the nuclear-encoded mitochondrial protein frataxin due to an abnormal GAA triplet repeat expansion in the first intron of the human FXN gene. FXN is evolutionarily conserved, with orthologs in essentially all eukaryotes and some prokaryotes, leading to the development of experimental models of this disease in different organisms. These FRDA models have contributed substantially to our current knowledge of frataxin function and the pathogenesis of the disease, as well as to explorations of suitable treatments. Drosophila melanogaster, an organism that is easy to manipulate genetically, has also become important in FRDA research. This review describes the substantial contribution of Drosophila to FRDA research since the characterization of the fly frataxin ortholog more than 15 years ago. Fly models have provided a comprehensive characterization of the defects associated with frataxin deficiency and have revealed genetic modifiers of disease phenotypes. In addition, these models are now being used in the search for potential therapeutic compounds for the treatment of this severe and still incurable disease.
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Affiliation(s)
- P. Calap-Quintana
- Department of Genetics, University of Valencia, Campus of Burjassot, Valencia, Spain
| | - J. A. Navarro
- Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - J. González-Fernández
- Department of Genetics, University of Valencia, Campus of Burjassot, Valencia, Spain
- Biomedical Research Institute INCLIVA, Valencia, Spain
| | | | - M. D. Moltó
- Department of Genetics, University of Valencia, Campus of Burjassot, Valencia, Spain
- Biomedical Research Institute INCLIVA, Valencia, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - J. V. Llorens
- Department of Genetics, University of Valencia, Campus of Burjassot, Valencia, Spain
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19
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Edenharter O, Schneuwly S, Navarro JA. Mitofusin-Dependent ER Stress Triggers Glial Dysfunction and Nervous System Degeneration in a Drosophila Model of Friedreich's Ataxia. Front Mol Neurosci 2018; 11:38. [PMID: 29563863 PMCID: PMC5845754 DOI: 10.3389/fnmol.2018.00038] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/29/2018] [Indexed: 11/13/2022] Open
Abstract
Friedreich's ataxia (FRDA) is the most important recessive ataxia in the Caucasian population. It is caused by a deficit of the mitochondrial protein frataxin. Despite its pivotal effect on biosynthesis of iron-sulfur clusters and mitochondrial energy production, little is known about the influence of frataxin depletion on homeostasis of the cellular mitochondrial network. We have carried out a forward genetic screen to analyze genetic interactions between genes controlling mitochondrial homeostasis and Drosophila frataxin. Our screen has identified silencing of Drosophila mitofusin (Marf) as a suppressor of FRDA phenotypes in glia. Drosophila Marf is known to play crucial roles in mitochondrial fusion, mitochondrial degradation and in the interface between mitochondria and endoplasmic reticulum (ER). Thus, we have analyzed the effects of frataxin knockdown on mitochondrial morphology, mitophagy and ER function in our fly FRDA model using different histological and molecular markers such as tetramethylrhodamine, ethyl ester (TMRE), mitochondria-targeted GFP (mitoGFP), p62, ATG8a, LAMP1, Xbp1 and BiP/GRP78. Furthermore, we have generated the first Drosophila transgenic line containing the mtRosella construct under the UAS control to study the progression of the mitophagy process in vivo. Our results indicated that frataxin-deficiency had a small impact on mitochondrial morphology but enhanced mitochondrial clearance and altered the ER stress response in Drosophila. Remarkably, we demonstrate that downregulation of Marf suppresses ER stress in frataxin-deficient cells and this is sufficient to improve locomotor dysfunction, brain degeneration and lipid dyshomeostasis in our FRDA model. In agreement, chemical reduction of ER stress by means of two different compounds was sufficient to ameliorate the effects of frataxin deficiency in three different fly FRDA models. Altogether, our results strongly suggest that the protection mediated by Marf knockdown in glia is mainly linked to its role in the mitochondrial-ER tethering and not to mitochondrial dynamics or mitochondrial degradation and that ER stress is a novel and pivotal player in the progression and etiology of FRDA. This work might define a new pathological mechanism in FRDA, linking mitochondrial dysfunction due to frataxin deficiency and mitofusin-mediated ER stress, which might be responsible for characteristic cellular features of the disease and also suggests ER stress as a therapeutic target.
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Affiliation(s)
- Oliver Edenharter
- Department of Developmental Biology, Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Stephan Schneuwly
- Department of Developmental Biology, Institute of Zoology, University of Regensburg, Regensburg, Germany
| | - Juan A. Navarro
- Department of Developmental Biology, Institute of Zoology, University of Regensburg, Regensburg, Germany
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20
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Lupoli F, Vannocci T, Longo G, Niccolai N, Pastore A. The role of oxidative stress in Friedreich's ataxia. FEBS Lett 2018; 592:718-727. [PMID: 29197070 PMCID: PMC5887922 DOI: 10.1002/1873-3468.12928] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 11/24/2017] [Accepted: 11/27/2017] [Indexed: 12/12/2022]
Abstract
Oxidative stress and an increase in the levels of free radicals are important markers associated with several pathologies, including Alzheimer's disease, cancer and diabetes. Friedreich's ataxia (FRDA) is an excellent paradigmatic example of a disease in which oxidative stress plays an important, albeit incompletely understood, role. FRDA is a rare genetic neurodegenerative disease that involves the partial silencing of frataxin, a small mitochondrial protein that was completely overlooked before being linked to FRDA. More than 20 years later, we now know how important this protein is in terms of being an essential and vital part of the machinery that produces iron-sulfur clusters in the cell. In this review, we revisit the most important steps that have brought us to our current understanding of the function of frataxin and its role in disease. We discuss the current hypotheses on the role of oxidative stress in FRDA and review some of the existing animal and cellular models. We also evaluate new techniques that can assist in the study of the disease mechanisms, as well as in our understanding of the interplay between primary and secondary phenotypes.
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Affiliation(s)
- Federica Lupoli
- Department of Biotechnology, Chemistry and PharmacyUniversity of SienaItaly
| | - Tommaso Vannocci
- The Maurice Wohl InstituteDementia Research CentreKing's College LondonUK
| | | | - Neri Niccolai
- Department of Biotechnology, Chemistry and PharmacyUniversity of SienaItaly
| | - Annalisa Pastore
- The Maurice Wohl InstituteDementia Research CentreKing's College LondonUK
- Department of Molecular MedicineUniversity of PaviaItaly
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21
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Marelja Z, Leimkühler S, Missirlis F. Iron Sulfur and Molybdenum Cofactor Enzymes Regulate the Drosophila Life Cycle by Controlling Cell Metabolism. Front Physiol 2018; 9:50. [PMID: 29491838 PMCID: PMC5817353 DOI: 10.3389/fphys.2018.00050] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/16/2018] [Indexed: 12/20/2022] Open
Abstract
Iron sulfur (Fe-S) clusters and the molybdenum cofactor (Moco) are present at enzyme sites, where the active metal facilitates electron transfer. Such enzyme systems are soluble in the mitochondrial matrix, cytosol and nucleus, or embedded in the inner mitochondrial membrane, but virtually absent from the cell secretory pathway. They are of ancient evolutionary origin supporting respiration, DNA replication, transcription, translation, the biosynthesis of steroids, heme, catabolism of purines, hydroxylation of xenobiotics, and cellular sulfur metabolism. Here, Fe-S cluster and Moco biosynthesis in Drosophila melanogaster is reviewed and the multiple biochemical and physiological functions of known Fe-S and Moco enzymes are described. We show that RNA interference of Mocs3 disrupts Moco biosynthesis and the circadian clock. Fe-S-dependent mitochondrial respiration is discussed in the context of germ line and somatic development, stem cell differentiation and aging. The subcellular compartmentalization of the Fe-S and Moco assembly machinery components and their connections to iron sensing mechanisms and intermediary metabolism are emphasized. A biochemically active Fe-S core complex of heterologously expressed fly Nfs1, Isd11, IscU, and human frataxin is presented. Based on the recent demonstration that copper displaces the Fe-S cluster of yeast and human ferredoxin, an explanation for why high dietary copper leads to cytoplasmic iron deficiency in flies is proposed. Another proposal that exosomes contribute to the transport of xanthine dehydrogenase from peripheral tissues to the eye pigment cells is put forward, where the Vps16a subunit of the HOPS complex may have a specialized role in concentrating this enzyme within pigment granules. Finally, we formulate a hypothesis that (i) mitochondrial superoxide mobilizes iron from the Fe-S clusters in aconitase and succinate dehydrogenase; (ii) increased iron transiently displaces manganese on superoxide dismutase, which may function as a mitochondrial iron sensor since it is inactivated by iron; (iii) with the Krebs cycle thus disrupted, citrate is exported to the cytosol for fatty acid synthesis, while succinyl-CoA and the iron are used for heme biosynthesis; (iv) as iron is used for heme biosynthesis its concentration in the matrix drops allowing for manganese to reactivate superoxide dismutase and Fe-S cluster biosynthesis to reestablish the Krebs cycle.
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Affiliation(s)
- Zvonimir Marelja
- Imagine Institute, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Silke Leimkühler
- Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Fanis Missirlis
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, Mexico
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22
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Edenharter O, Clement J, Schneuwly S, Navarro JA. Overexpression of Drosophila frataxin triggers cell death in an iron-dependent manner. J Neurogenet 2017; 31:189-202. [PMID: 28838288 DOI: 10.1080/01677063.2017.1363200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/31/2017] [Indexed: 10/24/2022]
Abstract
Friedreich ataxia (FRDA) is the most important autosomal recessive ataxia in the Caucasian population. FRDA patients display severe neurological and cardiac symptoms that reflect a strong cellular and axonal degeneration. FRDA is caused by a loss of function of the mitochondrial protein frataxin which impairs the biosynthesis of iron-sulfur clusters and in turn the catalytic activity of several enzymes in the Krebs cycle and the respiratory chain leading to a diminished energy production. Although FRDA is due to frataxin depletion, overexpression might also be very helpful to better understand cellular functions of frataxin. In this work, we have increased frataxin expression in neurons to elucidate specific roles that frataxin might play in these tissues. Using molecular, biochemical, histological and behavioral methods, we report that frataxin overexpression is sufficient to increase oxidative phosphorylation, modify mitochondrial morphology, alter iron homeostasis and trigger oxidative stress-dependent cell death. Interestingly, genetic manipulation of mitochondrial iron metabolism by silencing mitoferrin successfully improves cell survival under oxidative-attack conditions, although enhancing antioxidant defenses or mitochondrial fusion failed to ameliorate frataxin overexpression phenotypes. This result suggests that cell degeneration is directly related to enhanced incorporation of iron into the mitochondria. Drosophila frataxin overexpression might also provide an alternative approach to identify processes that are important in FRDA such as changes in mitochondrial morphology and oxidative stress induced cell death.
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Affiliation(s)
- Oliver Edenharter
- a Institute of Zoology , University of Regensburg , Regensburg , Germany
| | - Janik Clement
- a Institute of Zoology , University of Regensburg , Regensburg , Germany
| | - Stephan Schneuwly
- a Institute of Zoology , University of Regensburg , Regensburg , Germany
| | - Juan A Navarro
- a Institute of Zoology , University of Regensburg , Regensburg , Germany
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23
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Kemp K, Dey R, Cook A, Scolding N, Wilkins A. Mesenchymal Stem Cell-Derived Factors Restore Function to Human Frataxin-Deficient Cells. CEREBELLUM (LONDON, ENGLAND) 2017; 16:840-851. [PMID: 28456899 PMCID: PMC5498643 DOI: 10.1007/s12311-017-0860-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Friedreich's ataxia is an inherited neurological disorder characterised by mitochondrial dysfunction and increased susceptibility to oxidative stress. At present, no therapy has been shown to reduce disease progression. Strategies being trialled to treat Friedreich's ataxia include drugs that improve mitochondrial function and reduce oxidative injury. In addition, stem cells have been investigated as a potential therapeutic approach. We have used siRNA-induced knockdown of frataxin in SH-SY5Y cells as an in vitro cellular model for Friedreich's ataxia. Knockdown of frataxin protein expression to levels detected in patients with the disorder was achieved, leading to decreased cellular viability, increased susceptibility to hydrogen peroxide-induced oxidative stress, dysregulation of key anti-oxidant molecules and deficiencies in both cell proliferation and differentiation. Bone marrow stem cells are being investigated extensively as potential treatments for a wide range of neurological disorders, including Friedreich's ataxia. The potential neuroprotective effects of bone marrow-derived mesenchymal stem cells were therefore studied using our frataxin-deficient cell model. Soluble factors secreted by mesenchymal stem cells protected against cellular changes induced by frataxin deficiency, leading to restoration in frataxin levels and anti-oxidant defences, improved survival against oxidative stress and stimulated both cell proliferation and differentiation down the Schwann cell lineage. The demonstration that mesenchymal stem cell-derived factors can restore cellular homeostasis and function to frataxin-deficient cells further suggests that they may have potential therapeutic benefits for patients with Friedreich's ataxia.
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Affiliation(s)
- Kevin Kemp
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK.
| | - Rimi Dey
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Amelia Cook
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Neil Scolding
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
| | - Alastair Wilkins
- Multiple Sclerosis and Stem Cell Group, School of Clinical Sciences, Clinical Neurosciences office, University of Bristol, 1st floor, Learning and Research building, Southmead Hospital, Bristol, BS10 5NB, UK
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Tamarit J, Obis È, Ros J. Oxidative stress and altered lipid metabolism in Friedreich ataxia. Free Radic Biol Med 2016; 100:138-146. [PMID: 27296838 DOI: 10.1016/j.freeradbiomed.2016.06.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/07/2016] [Accepted: 06/10/2016] [Indexed: 12/31/2022]
Abstract
Friedreich ataxia is a genetic disease caused by the deficiency of frataxin, a mitochondrial protein. Frataxin deficiency impacts in the cell physiology at several levels. One of them is oxidative stress with consequences in terms of protein dysfunctions and metabolic alterations. Among others, alterations in lipid metabolism have been observed in several models of the disease. In this review we summarize the current knowledge of the molecular basis of the disease, the relevance of oxidative stress and the therapeutic strategies based on reduction of mitochondrial reactive oxygen species production. Finally, we will focus the interest in alterations of lipid metabolism as a consequence of mitochondrial dysfunction and describe the therapeutic approaches based on targeting lipid metabolism.
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Affiliation(s)
- Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Èlia Obis
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, IRB-Lleida, Universitat de Lleida, Lleida, Spain.
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25
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Piermarini E, Cartelli D, Pastore A, Tozzi G, Compagnucci C, Giorda E, D'Amico J, Petrini S, Bertini E, Cappelletti G, Piemonte F. Frataxin silencing alters microtubule stability in motor neurons: implications for Friedreich's ataxia. Hum Mol Genet 2016; 25:4288-4301. [PMID: 27516386 DOI: 10.1093/hmg/ddw260] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 07/04/2016] [Accepted: 07/19/2016] [Indexed: 12/23/2022] Open
Abstract
To elucidate the pathogenesis of axonopathy in Friedreich's Ataxia (FRDA), a neurodegenerative disease characterized by axonal retraction, we analyzed the microtubule (MT) dynamics in an in vitro frataxin-silenced neuronal model (shFxn). A typical feature of MTs is their "dynamic instability", in which they undergo phases of growth (polymerization) and shrinkage (depolymerization). MTs play a fundamental role in the physiology of neurons and every perturbation of their dynamicity is highly detrimental for neuronal functions. The aim of this study is to determine whether MTs are S-glutathionylated in shFxn and if the glutathionylation triggers MT dysfunction. We hypothesize that oxidative stress, determined by high GSSG levels, induces axonal retraction by interfering with MT dynamics. We propose a mechanism of the axonopathy in FRDA where GSSG overload and MT de-polymerization are strictly interconnected. Indeed, using a frataxin-silenced neuronal model we show a significant reduction of neurites extension, a shift of tubulin toward the unpolymerized fraction and a consistent increase of glutathione bound to the cytoskeleton. The live cell imaging approach further reveals a significant decrease in MT growth lifetime due to frataxin silencing, which is consistent with the MT destabilization. The in vitro antioxidant treatments trigger the axonal re-growth and the increase in stable MTs in shFxn, thus contributing to identify new neuronal targets of oxidation in this disease and providing a novel approach for antioxidant therapies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Graziella Cappelletti
- Department of Biosciences
- Center of Excellence on Neurodegenerative Diseases, University of Milan, Via Celoria 26, Milan, Italy
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Soriano S, Calap-Quintana P, Llorens JV, Al-Ramahi I, Gutiérrez L, Martínez-Sebastián MJ, Botas J, Moltó MD. Metal Homeostasis Regulators Suppress FRDA Phenotypes in a Drosophila Model of the Disease. PLoS One 2016; 11:e0159209. [PMID: 27433942 PMCID: PMC4951068 DOI: 10.1371/journal.pone.0159209] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/28/2016] [Indexed: 11/19/2022] Open
Abstract
Friedreich's ataxia (FRDA), the most commonly inherited ataxia in populations of European origin, is a neurodegenerative disorder caused by a decrease in frataxin levels. One of the hallmarks of the disease is the accumulation of iron in several tissues including the brain, and frataxin has been proposed to play a key role in iron homeostasis. We found that the levels of zinc, copper, manganese and aluminum were also increased in a Drosophila model of FRDA, and that copper and zinc chelation improve their impaired motor performance. By means of a candidate genetic screen, we identified that genes implicated in iron, zinc and copper transport and metal detoxification can restore frataxin deficiency-induced phenotypes. Taken together, these results demonstrate that the metal dysregulation in FRDA includes other metals besides iron, therefore providing a new set of potential therapeutic targets.
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Affiliation(s)
- Sirena Soriano
- Department of Genetics, University of Valencia, Burjassot, Valencia, Spain
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | | | | | - Ismael Al-Ramahi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lucía Gutiérrez
- Department of Biomaterials and Bioinspired Materials, Instituto de Ciencia de Materiales de Madrid/CSIC, Madrid, Spain
| | | | - Juan Botas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - María Dolores Moltó
- Department of Genetics, University of Valencia, Burjassot, Valencia, Spain
- CIBERSAM, INCLIVA, Valencia, Spain
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27
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Chen K, Lin G, Haelterman NA, Ho TSY, Li T, Li Z, Duraine L, Graham BH, Jaiswal M, Yamamoto S, Rasband MN, Bellen HJ. Loss of Frataxin induces iron toxicity, sphingolipid synthesis, and Pdk1/Mef2 activation, leading to neurodegeneration. eLife 2016; 5:e16043. [PMID: 27343351 PMCID: PMC4956409 DOI: 10.7554/elife.16043] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/24/2016] [Indexed: 12/22/2022] Open
Abstract
Mutations in Frataxin (FXN) cause Friedreich's ataxia (FRDA), a recessive neurodegenerative disorder. Previous studies have proposed that loss of FXN causes mitochondrial dysfunction, which triggers elevated reactive oxygen species (ROS) and leads to the demise of neurons. Here we describe a ROS independent mechanism that contributes to neurodegeneration in fly FXN mutants. We show that loss of frataxin homolog (fh) in Drosophila leads to iron toxicity, which in turn induces sphingolipid synthesis and ectopically activates 3-phosphoinositide dependent protein kinase-1 (Pdk1) and myocyte enhancer factor-2 (Mef2). Dampening iron toxicity, inhibiting sphingolipid synthesis by Myriocin, or reducing Pdk1 or Mef2 levels, all effectively suppress neurodegeneration in fh mutants. Moreover, increasing dihydrosphingosine activates Mef2 activity through PDK1 in mammalian neuronal cell line suggesting that the mechanisms are evolutionarily conserved. Our results indicate that an iron/sphingolipid/Pdk1/Mef2 pathway may play a role in FRDA.
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Affiliation(s)
- Kuchuan Chen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Guang Lin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Tammy Szu-Yu Ho
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
| | - Zhihong Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Lita Duraine
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Brett H Graham
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Manish Jaiswal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
| | - Shinya Yamamoto
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
| | - Matthew N Rasband
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, United States
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, United States
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28
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Crombie DE, Pera MF, Delatycki MB, Pébay A. Using human pluripotent stem cells to study Friedreich ataxia cardiomyopathy. Int J Cardiol 2016; 212:37-43. [PMID: 27019046 DOI: 10.1016/j.ijcard.2016.03.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 03/02/2016] [Accepted: 03/13/2016] [Indexed: 12/16/2022]
Abstract
Friedreich ataxia (FRDA) is the most common of the inherited ataxias. It is an autosomal recessive disease characterised by degeneration of peripheral sensory neurons, regions of the central nervous system and cardiomyopathy. FRDA is usually due to homozygosity for trinucleotide GAA repeat expansions found within first intron of the FRATAXIN (FXN) gene, which results in reduced levels of the mitochondrial protein FXN. Reduced FXN protein results in mitochondrial dysfunction and iron accumulation leading to increased oxidative stress and cell death in the nervous system and heart. Yet the precise functions of FXN and the underlying mechanisms leading to disease pathology remain elusive. This is particularly true of the cardiac aspect of FRDA, which remains largely uncharacterized at the cellular level. Here, we summarise current knowledge on experimental models in which to study FRDA cardiomyopathy, with a particular focus on the use of human pluripotent stem cells as a disease model.
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Affiliation(s)
- Duncan E Crombie
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Australia
| | - Martin F Pera
- Department of Anatomy and Neurosciences, The University of Melbourne, Florey Neuroscience & Mental Health Institute, Walter and Eliza Hall Institute of Medical Research, Australia
| | - Martin B Delatycki
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Department of Paediatrics, The University of Melbourne, Australia; School of Psychology and Psychiatry, Monash University, Australia; Clinical Genetics, Austin Health, Australia
| | - Alice Pébay
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Australia.
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29
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Kumar S, Wang J, Rani R, Gandhi CR. Hepatic Deficiency of Augmenter of Liver Regeneration Exacerbates Alcohol-Induced Liver Injury and Promotes Fibrosis in Mice. PLoS One 2016; 11:e0147864. [PMID: 26808690 PMCID: PMC4726524 DOI: 10.1371/journal.pone.0147864] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/08/2016] [Indexed: 12/29/2022] Open
Abstract
Why only a subpopulation (about 15%) of humans develops liver cirrhosis due to alcohol is a critical as yet unanswered question. Liver-specific depletion of augmenter of liver regeneration (ALR) protein in mice causes robust steatosis and hepatocyte apoptosis by 2 weeks; these pathologies regress subsequently with return of ALR expression even at lower than control levels, but the mice develop modest steatohepatitis by 8 weeks. We aimed to investigate whether chronic alcohol ingestion promotes excessive hepatic fibrosis in these ALR-deficient mice. Liver-specific ALR-deficient and wild type (WT) female mice (8–10 weeks old) were placed on 4% alcohol-supplemented or isocaloric diet for 4 weeks. Liver sections were examined for histopathology, and parameters of steatosis and fibrosis were quantified. The mRNA expression of alcohol dehydrogenase-1, acetaldehyde dehydrogenase-1 and cytochrome P450-2E1 increased in WT mice but decreased in ALR-deficient mice upon alcohol ingestion. While alcohol induced steatosis and mild inflammation in WT mice, ALR-deficient mice showed minimal steatosis, strong hepatocellular injury and inflammation, prominent ductular proliferation, and robust fibrosis. Compared to the WT mice, alcohol feeding of ALR-deficient mice resulted in significantly greater increase in hepatic TNFα and TGFβ, and oxidative stress; there was also hepatic iron accumulation, robust lipid peroxidation and mitochondrial DNA damage. Importantly, similar to ALR-deficient mice, lower hepatic ALR levels in human alcoholic liver cirrhosis were associated with increased iron content, reduced expression of alcohol dehydrogenase and acetaldehyde dehydrogenase, and elevated fibrogenic markers. We conclude that ALR deficiency or anomaly can play a critical role in alcohol-induced hepatic fibrosis/cirrhosis, mechanisms of which may involve dysregulation of alcohol metabolism and iron homeostasis, mitochondrial damage and oxidative injury.
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Affiliation(s)
- Sudhir Kumar
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, United States of America
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
| | - Jiang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Richa Rani
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, United States of America
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
| | - Chandrashekhar R. Gandhi
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, United States of America
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United states of America
- * E-mail:
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30
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Seguin A, Monnier V, Palandri A, Bihel F, Rera M, Schmitt M, Camadro JM, Tricoire H, Lesuisse E. A Yeast/Drosophila Screen to Identify New Compounds Overcoming Frataxin Deficiency. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:565140. [PMID: 26523199 PMCID: PMC4619980 DOI: 10.1155/2015/565140] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/26/2014] [Accepted: 01/06/2015] [Indexed: 11/17/2022]
Abstract
Friedreich's ataxia (FA) is a rare neurodegenerative disease which is very debilitating for the patients who progressively lose their autonomy. The lack of efficient therapeutic treatment of the disease strongly argues for urgent need to search for new active compounds that may stop the progression of the disease or prevent the appearance of the symptoms when the genetic defect is diagnosed early enough. In the present study, we used a yeast strain with a deletion of the frataxin homologue gene as a model of FA cells in a primary screen of two chemical libraries, a fraction of the French National Chemical Library (5500 compounds) and the Prestwick collection (880 compounds). We ran a secondary screen on Drosophila melanogaster flies expressing reduced levels of frataxin during larval development. Half of the compounds selected in yeast appeared to be active in flies in this developmental paradigm, and one of the two compounds with highest activities in this assay partially rescued the heart dilatation phenotype resulting from heart specific depletion of frataxin. The unique complementarity of these two frataxin-deficient models, unicellular and multicellular, appears to be very efficient to select new compounds with improved selectivity, bringing significant perspectives towards improvements in FA therapy.
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Affiliation(s)
- Alexandra Seguin
- “Mitochondries, Métaux et Stress Oxydant”, Institut Jacques Monod, UMR7592 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Véronique Monnier
- Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR8251 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 4 rue M. A. Lagroua Weill Halle, 75205 Paris Cedex 13, France
| | - Amandine Palandri
- Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR8251 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 4 rue M. A. Lagroua Weill Halle, 75205 Paris Cedex 13, France
| | - Frédéric Bihel
- Laboratoire d'Innovation Thérapeutique, UMR7200 CNRS-Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, BP 60024, 67401 Illkirch Cedex, France
| | - Michael Rera
- Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR8251 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 4 rue M. A. Lagroua Weill Halle, 75205 Paris Cedex 13, France
| | - Martine Schmitt
- Laboratoire d'Innovation Thérapeutique, UMR7200 CNRS-Université de Strasbourg, Faculté de Pharmacie, 74 route du Rhin, BP 60024, 67401 Illkirch Cedex, France
| | - Jean-Michel Camadro
- “Mitochondries, Métaux et Stress Oxydant”, Institut Jacques Monod, UMR7592 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Hervé Tricoire
- Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR8251 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 4 rue M. A. Lagroua Weill Halle, 75205 Paris Cedex 13, France
| | - Emmanuel Lesuisse
- “Mitochondries, Métaux et Stress Oxydant”, Institut Jacques Monod, UMR7592 CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
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31
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O’Keefe LV, Lee CS, Choo A, Richards RI. Tumor Suppressor WWOX Contributes to the Elimination of Tumorigenic Cells in Drosophila melanogaster. PLoS One 2015; 10:e0136356. [PMID: 26302329 PMCID: PMC4547717 DOI: 10.1371/journal.pone.0136356] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/31/2015] [Indexed: 01/27/2023] Open
Abstract
WWOX is a >1Mb gene spanning FRA16D Common Chromosomal Fragile Site, a region of DNA instability in cancer. Consequently, altered WWOX levels have been observed in a wide variety of cancers. In vitro studies have identified a large number and variety of potential roles for WWOX. Although its normal role in vivo and functional contribution to cancer have not been fully defined, WWOX does have an integral role in metabolism and can suppress tumor growth. Using Drosophila melanogaster as an in vivo model system, we find that WWOX is a modulator of TNFα/Egr-mediated cell death. We found that altered levels of WWOX can modify phenotypes generated by low level ectopic expression of TNFα/Egr and this corresponds to altered levels of Caspase 3 activity. These results demonstrate an in vivo role for WWOX in promoting cell death. This form of cell death is accompanied by an increase in levels of reactive oxygen species, the regulation of which we have previously shown can also be modified by altered WWOX activity. We now hypothesise that, through regulation of reactive oxygen species, WWOX constitutes a link between alterations in cellular metabolism observed in cancer cells and their ability to evade normal cell death pathways. We have further shown that WWOX activity is required for the efficient removal of tumorigenic cells from a developing epithelial tissue. Together these results provide a molecular basis for the tumor suppressor functions of WWOX and the better prognosis observed in cancer patients with higher levels of WWOX activity. Understanding the conserved cellular pathways to which WWOX contributes provides novel possibilities for the development of therapeutic approaches to restore WWOX function in cancer.
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Affiliation(s)
- Louise V. O’Keefe
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Cheng Shoou Lee
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Amanda Choo
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Robert I. Richards
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
- * E-mail:
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32
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Navarro JA, Botella JA, Metzendorf C, Lind MI, Schneuwly S. Mitoferrin modulates iron toxicity in a Drosophila model of Friedreich's ataxia. Free Radic Biol Med 2015; 85:71-82. [PMID: 25841783 DOI: 10.1016/j.freeradbiomed.2015.03.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/26/2015] [Accepted: 03/13/2015] [Indexed: 01/12/2023]
Abstract
Friedreich's ataxia is the most important recessive ataxia in the Caucasian population. Loss of frataxin expression affects the production of iron-sulfur clusters and, therefore, mitochondrial energy production. One of the pathological consequences is an increase of iron transport into the mitochondrial compartment leading to a toxic accumulation of reactive iron. However, the mechanism underlying this inappropriate mitochondrial iron accumulation is still unknown. Control and frataxin-deficient flies were fed with an iron diet in order to mimic an iron overload and used to assess various cellular as well as mitochondrial functions. We showed that frataxin-deficient flies were hypersensitive toward dietary iron and developed an iron-dependent decay of mitochondrial functions. In the fly model exhibiting only partial frataxin loss, we demonstrated that the inability to activate ferritin translation and the enhancement of mitochondrial iron uptake via mitoferrin upregulation were likely the key molecular events behind the iron-induced phenotype. Both defects were observed during the normal process of aging, confirming their importance in the progression of the pathology. In an effort to further assess the importance of these mechanisms, we carried out genetic interaction studies. We showed that mitoferrin downregulation improved many of the frataxin-deficient conditions, including nervous system degeneration, whereas mitoferrin overexpression exacerbated most of them. Taken together, this study demonstrates the crucial role of mitoferrin dysfunction in the etiology of Friedreich's ataxia and provides evidence that impairment of mitochondrial iron transport could be an effective treatment of the disease.
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Affiliation(s)
- Juan A Navarro
- Institute of Zoology, University of Regensburg, Universitaetsstrasse 31, 93040 Regensburg, Germany.
| | - Jose A Botella
- Institute of Zoology, University of Regensburg, Universitaetsstrasse 31, 93040 Regensburg, Germany
| | - Christoph Metzendorf
- Biochemistry Center, Heidelberg University, Im Neuenheimer Feld 328, 69120 Heidelberg, Germany
| | - Maria I Lind
- Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden
| | - Stephan Schneuwly
- Institute of Zoology, University of Regensburg, Universitaetsstrasse 31, 93040 Regensburg, Germany
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33
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Calap-Quintana P, Soriano S, Llorens JV, Al-Ramahi I, Botas J, Moltó MD, Martínez-Sebastián MJ. TORC1 Inhibition by Rapamycin Promotes Antioxidant Defences in a Drosophila Model of Friedreich's Ataxia. PLoS One 2015; 10:e0132376. [PMID: 26158631 PMCID: PMC4497667 DOI: 10.1371/journal.pone.0132376] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/14/2015] [Indexed: 12/22/2022] Open
Abstract
Friedreich's ataxia (FRDA), the most common inherited ataxia in the Caucasian population, is a multisystemic disease caused by a significant decrease in the frataxin level. To identify genes capable of modifying the severity of the symptoms of frataxin depletion, we performed a candidate genetic screen in a Drosophila RNAi-based model of FRDA. We found that genetic reduction in TOR Complex 1 (TORC1) signalling improves the impaired motor performance phenotype of FRDA model flies. Pharmacologic inhibition of TORC1 signalling by rapamycin also restored this phenotype and increased the lifespan and ATP levels. Furthermore, rapamycin reduced the altered levels of malondialdehyde + 4-hydroxyalkenals and total glutathione of the model flies. The rapamycin-mediated protection against oxidative stress is due in part to an increase in the transcription of antioxidant genes mediated by cap-n-collar (Drosophila ortholog of Nrf2). Our results suggest that autophagy is indeed necessary for the protective effect of rapamycin in hyperoxia. Rapamycin increased the survival and aconitase activity of model flies subjected to high oxidative insult, and this improvement was abolished by the autophagy inhibitor 3-methyladenine. These results point to the TORC1 pathway as a new potential therapeutic target for FRDA and as a guide to finding new promising molecules for disease treatment.
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Affiliation(s)
| | - Sirena Soriano
- Department of Genetics, University of Valencia, Burjassot, Valencia, Spain
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | | | - Ismael Al-Ramahi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Juan Botas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - María Dolores Moltó
- Department of Genetics, University of Valencia, Burjassot, Valencia, Spain
- CIBERSAM, INCLIVA, Valencia, Spain
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Palandri A, L'hôte D, Cohen-Tannoudji J, Tricoire H, Monnier V. Frataxin inactivation leads to steroid deficiency in flies and human ovarian cells. Hum Mol Genet 2015; 24:2615-26. [PMID: 25628335 DOI: 10.1093/hmg/ddv024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 01/21/2015] [Indexed: 01/26/2023] Open
Abstract
Friedreich ataxia (FA), the most common inherited autosomal-recessive ataxia in Caucasians, is characterized by progressive degeneration of the central and peripheral nervous system, hypertrophic cardiomyopathy and increased incidence of diabetes. FA is caused by a GAA repeat expansion in the first intron of the gene encoding frataxin, an evolutionarily conserved mitochondrial protein, which results in decreased gene expression. Ubiquitous inactivation of the fly frataxin ortholog dfh blocks the transition from larval to pupal stages. In this study, we show that this phenotype is due to ecdysteroid deficiency and that feeding larvae with the 20-hydroxyecdysone steroid hormone rescues this developmental blockage. In mammals, adrenodoxin, the ferredoxin FDX1, is an Fe-S-containing protein essential for the synthesis of various steroid hormones. We show here that the two fly ferredoxins, Fdxh and Fdxh2 (encoded by CG1319), are also involved in steroidogenesis. This provides a potent mechanism by which frataxin, known to be involved in Fe-S cluster biosynthesis, could affect steroidogenesis through reduced ferredoxin activity. Finally, we show that frataxin inactivation decreases progesterone synthesis in human KGN ovarian granulosa cells. Thus, the involvement of frataxin in steroid synthesis appears to be a conserved function of the protein from flies to human and our data suggest that steroidogenesis could be affected in FA patients.
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Affiliation(s)
- Amandine Palandri
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) CNRS UMR8251, Paris, France and
| | - David L'hôte
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) CNRS UMR8251, Paris, France and INSERM U1133, Physiologie de l'Axe Gonadotrope, F-75013 Paris, France
| | - Joëlle Cohen-Tannoudji
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) CNRS UMR8251, Paris, France and INSERM U1133, Physiologie de l'Axe Gonadotrope, F-75013 Paris, France
| | - Hervé Tricoire
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) CNRS UMR8251, Paris, France and
| | - Véronique Monnier
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative (BFA) CNRS UMR8251, Paris, France and
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Igoillo-Esteve M, Gurgul-Convey E, Hu A, Romagueira Bichara Dos Santos L, Abdulkarim B, Chintawar S, Marselli L, Marchetti P, Jonas JC, Eizirik DL, Pandolfo M, Cnop M. Unveiling a common mechanism of apoptosis in β-cells and neurons in Friedreich's ataxia. Hum Mol Genet 2015; 24:2274-86. [PMID: 25552656 DOI: 10.1093/hmg/ddu745] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a neurodegenerative disorder associated with cardiomyopathy and diabetes. Effective therapies for FRDA are an urgent unmet need; there are currently no options to prevent or treat this orphan disease. FRDA is caused by reduced expression of the mitochondrial protein frataxin. We have previously demonstrated that pancreatic β-cell dysfunction and death cause diabetes in FRDA. This is secondary to mitochondrial dysfunction and apoptosis but the underlying molecular mechanisms are not known. Here we show that β-cell demise in frataxin deficiency is the consequence of oxidative stress-mediated activation of the intrinsic pathway of apoptosis. The pro-apoptotic Bcl-2 family members Bad, DP5 and Bim are the key mediators of frataxin deficiency-induced β-cell death. Importantly, the intrinsic pathway of apoptosis is also activated in FRDA patients' induced pluripotent stem cell-derived neurons. Interestingly, cAMP induction normalizes mitochondrial oxidative status and fully prevents activation of the intrinsic pathway of apoptosis in frataxin-deficient β-cells and neurons. This preclinical study suggests that incretin analogs hold potential to prevent/delay both diabetes and neurodegeneration in FRDA.
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Affiliation(s)
| | - Ewa Gurgul-Convey
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover 30625, Germany
| | - Amélie Hu
- Laboratory of Experimental Neurology, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Laila Romagueira Bichara Dos Santos
- Institut de Recherche Expérimentale et Clinique, Pôle d' Endocrinologie, Diabète et Nutrition, Université Catholique de Louvain, Brussels 1200, Belgium
| | | | - Satyan Chintawar
- Laboratory of Experimental Neurology, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Lorella Marselli
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy and
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy and
| | - Jean-Christophe Jonas
- Institut de Recherche Expérimentale et Clinique, Pôle d' Endocrinologie, Diabète et Nutrition, Université Catholique de Louvain, Brussels 1200, Belgium
| | | | - Massimo Pandolfo
- Laboratory of Experimental Neurology, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Miriam Cnop
- ULB Center for Diabetes Research and, Division of Endocrinology, Erasmus Hospital, 1070, Brussels, Belgium
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Mitochondrial diseases: Drosophila melanogaster as a model to evaluate potential therapeutics. Int J Biochem Cell Biol 2015; 63:60-5. [PMID: 25666557 DOI: 10.1016/j.biocel.2015.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/19/2015] [Accepted: 01/29/2015] [Indexed: 01/26/2023]
Abstract
While often presented as a single entity, mitochondrial diseases comprise a wide range of clinical, biochemical and genetic heterogeneous disorders. Among them, defects in the process of oxidative phosphorylation are the most prevalent. Despite intense research efforts, patients are still without effective treatment. An important part of the development of new therapeutics relies on predictive models of the pathology in order to assess their therapeutic potential. Since mitochondrial diseases are a heterogeneous group of progressive multisystemic disorders that can affect any organ at any time, the development of various in vivo models for the different diseases-associated genes defects will accelerate the search for effective therapeutics. Here, we review existing Drosophila melanogaster models for mitochondrial diseases, with a focus on alterations in oxidative phosphorylation, and discuss the potential of this powerful model organism in the process of drug target discovery. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.
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Friedreich's Ataxia: A Neuronal Point of View on the Oxidative Stress Hypothesis. Antioxidants (Basel) 2014; 3:592-603. [PMID: 26785073 PMCID: PMC4665420 DOI: 10.3390/antiox3030592] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 05/06/2014] [Accepted: 05/16/2014] [Indexed: 12/02/2022] Open
Abstract
A prominent feature of Friedreich’s ataxia (FRDA) is the neurodegeneration of the central and peripheral nervous systems, but little information is available about the mechanisms leading to neuronal damage in this pathology. Currently, no treatments delay, prevent, or reverse the inexorable decline that occurs in this condition. Evidence of oxidative damage has been demonstrated in Friedreich’s ataxia, and this damage has been proposed as the origin of the disease. Nevertheless, the role of oxidative stress in FRDA remains debatable. The lack of direct evidence of reactive oxygen species overproduction in FRDA cells and tissues and the failure of exogenous antioxidants to rescue FRDA phenotypes questions the role of oxidative stress in this pathology. For example, the antioxidant “idebenone” ameliorates cardiomyopathy in FRDA patients, but this therapy does not improve neurodegeneration. To date, no known pharmacological treatment with antioxidant properties cures or delays FRDA neuropathology. This review reports and discusses the evidence of oxidative stress in FRDA and focuses on the existing knowledge of the apparent ineffectiveness of antioxidants for the treatment of neuronal damage.
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Robb EL, Christoff CA, Maddalena LA, Stuart JA. Mitochondrial reactive oxygen species (ROS) in animal cells: relevance to aging and normal physiology. CAN J ZOOL 2014. [DOI: 10.1139/cjz-2013-0131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In animal mitochondria, the four electron reduction of molecular oxygen to produce water at respiratory complex IV is the terminal step in substrate oxidation. However, respiratory complexes I, II, and III can participate in the single electron reduction of oxygen to produce the radical species superoxide. This progenitor reactive oxygen species (ROS) participates in a number of reactions that generate other ROS. These molecules may react with, and damage, intracellular macromolecules, leading to cellular dysfunction. Mitochondrial ROS production is often considered from this perspective of macromolecular damage and is central to the “oxidative damage theory of aging”, which suggests the accumulation of oxidative damage in animal cells underlies the aging phenotype and limits lifespan. In this review, we discuss some experimental results accumulated over the past decade that are inconsistent with this theory. A limitation of the theory is that it presupposes mitochondrial ROS are inherently harmful. However, it is increasingly apparent that some basic cellular functions are physiologically regulated by normal levels of mitochondrial ROS. For example, cell growth and division, the apoptotic pathway, and mitochondrial fusion–fission dynamics all appear to be redox-regulated by mitochondrial ROS and perhaps the matrix manganese superoxide dismutase (MnSOD). Therefore, it is less clear how the balance between ROS regulation of normal cellular activities and ROS-mediated macromolecular damage is maintained and how this relates to aging and longevity in animals.
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Affiliation(s)
- Ellen L. Robb
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Casey A. Christoff
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Lucas A. Maddalena
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Jeffrey A. Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
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Tricoire H, Palandri A, Bourdais A, Camadro JM, Monnier V. Methylene blue rescues heart defects in a Drosophila model of Friedreich's ataxia. Hum Mol Genet 2014; 23:968-79. [PMID: 24105471 DOI: 10.1093/hmg/ddt493] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Friedreich's ataxia (FRDA), the most common hereditary ataxia, is characterized by progressive degeneration of the central and peripheral nervous system, hypertrophic cardiomyopathy and a high risk of diabetes. FRDA is caused by abnormally low levels of frataxin, a highly conserved mitochondrial protein. Drosophila has been previously successfully used to model FRDA in various cell types, including neurons and glial cells. Here, we report the development of a Drosophila cardiac model of FRDA. In vivo heart imaging revealed profound impairments in heart function in frataxin-depleted Drosophila, including a strong increase in end-systolic and end-diastolic diameters and a decrease in fractional shortening (FS). These features, reminiscent of pathological phenotypes in humans, are fully rescued by complementation with human frataxin, suggesting conserved cardiac functions of frataxin between the two organisms. Oxidative stress is not a major factor of heart impairment in frataxin-depleted flies, suggesting the involvement of other pathological mechanisms notably mitochondrial respiratory chain (MRC) dysfunction. Accordingly, we report that methylene blue (MB), a compound known to act as an alternative electron carrier that bypasses mitochondrial complexes I-III, was able to prevent heart dysfunction. MB also partially rescued the phenotype when administered post-symptomatically. Analysis of MB derivatives demonstrates that only compounds with electron carrier properties are able to prevent the heart phenotype. Thus MB, a compound already used for several clinical applications, appears promising for the treatment of the heart dysfunctions that are a major cause of death of FRDA patients. This work provides the grounds for further evaluation of MB action in mammals.
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Affiliation(s)
- Hervé Tricoire
- Unité de Biologie Fonctionnelle et Adaptative (BFA) EAC4413 CNRS, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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Moreno-Cermeño A, Alsina D, Cabiscol E, Tamarit J, Ros J. Metabolic remodeling in frataxin-deficient yeast is mediated by Cth2 and Adr1. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1833:3326-3337. [PMID: 24100161 DOI: 10.1016/j.bbamcr.2013.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 09/10/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022]
Abstract
Frataxin is a mitochondrial protein involved in iron metabolism whose deficiency in humans causes Friedreich ataxia. We performed transcriptomic and proteomic analyses of conditional Yeast Frataxin Homologue (Yfh1) mutants (tetO7-YFH1) to investigate metabolic remodeling upon Yfh1 depletion. These studies revealed that Yfh1 depletion leads to downregulation of many glucose-repressed genes. Most of them were Adr1 targets, a key transcription factor required for growth in non-fermentable carbon sources. Using a GFP-tagged Adr1, we observed that Yfh1 depletion promotes the export of Adr1 from the nucleus to the cytosol without affecting its protein levels. This effect was also observed upon H2O2 treatment, but not by iron overload/starvation, indicating the presence of a regulatory pathway involved in Adr1 export and inactivation upon stress conditions. We also observed that CTH2, a gene involved in the mRNA degradation of several iron-containing enzymes, was induced upon Yfh1 depletion. Accordingly, decreased levels of aconitase and succinate dehydrogenase were observed. Nevertheless, their levels were maintained in a Δcth2 mutant even in the absence of Yfh1. From these results we can conclude that, in addition to altering iron homeostasis, frataxin depletion involves drastic metabolic remodeling governed by Adr1 and Cth2 that finally leads to downregulation of iron-sulfur proteins and other proteins involved in respiratory metabolism.
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Affiliation(s)
- Armando Moreno-Cermeño
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, IRB-Lleida, Universitat de Lleida, Lleida, Spain.
| | - David Alsina
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Elisa Cabiscol
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Jordi Tamarit
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, IRB-Lleida, Universitat de Lleida, Lleida, Spain
| | - Joaquim Ros
- Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, IRB-Lleida, Universitat de Lleida, Lleida, Spain.
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41
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Shan Y, Schoenfeld RA, Hayashi G, Napoli E, Akiyama T, Iodi Carstens M, Carstens EE, Pook MA, Cortopassi GA. Frataxin deficiency leads to defects in expression of antioxidants and Nrf2 expression in dorsal root ganglia of the Friedreich's ataxia YG8R mouse model. Antioxid Redox Signal 2013; 19:1481-93. [PMID: 23350650 PMCID: PMC3797453 DOI: 10.1089/ars.2012.4537] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 01/23/2013] [Accepted: 01/26/2013] [Indexed: 12/11/2022]
Abstract
AIMS Oxidative stress is thought to be involved in Friedreich's ataxia (FRDA), yet it has not been demonstrated in the target neurons that are first to degenerate. Using the YG8R mouse model of FRDA, microarray and neuritic growth experiments were carried out in the dorsal root ganglion (DRG), the primary site of neurodegeneration in this disease. RESULTS YG8R hemizygous mice exhibited defects in movement, and DRG neurites had growth defects. Microarray of DRG tissue identified decreased transcripts encoding the antioxidants, including peroxiredoxins, glutaredoxins, and glutathione S-transferase, and these were confirmed by immunoblots and quantitative real-time PCR. Because the decreased gene transcripts are the known targets of the antioxidant transcription factor nuclear factor-E2-related factor-2 (Nrf2), Nrf2 expression was measured; it was significantly decreased at the transcript and protein level in both the DRG and the cerebella of the YG8R hemizygous mouse; further, frataxin expression was significantly correlated with Nrf2 expression. Functionally, in YG8R hemizygous DRG, the total glutathione levels were reduced and explanted cells were more sensitive to the thioredoxin reductase (TxnRD) inhibitor auranofin, a thiol oxidant. In cell models of FRDA, including Schwann and the DRG, frataxin deficiency caused a decreased expression of the Nrf2 protein level in the nucleus, but not a defect in its translocation from the cytosol. Further, frataxin-deficient cells had decreased enzyme activity and expression of TxnRD, which is regulated by Nrf2, and were sensitive the TxnRD inhibitor auranofin. INNOVATION AND CONCLUSION These results support a mechanistic hypothesis in which frataxin deficiency decreases Nrf2 expression in vivo, causing the sensitivity to oxidative stress in target tissues the DRG and the cerebella, which contributes to the process of neurodegeneration.
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Affiliation(s)
- Yuxi Shan
- Department of Molecular Biosciences, University of California, Davis, California
| | - Robert A. Schoenfeld
- Department of Molecular Biosciences, University of California, Davis, California
| | - Genki Hayashi
- Department of Molecular Biosciences, University of California, Davis, California
| | - Eleonora Napoli
- Department of Molecular Biosciences, University of California, Davis, California
| | - Tasuku Akiyama
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - Mirela Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - Earl E. Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, California
| | - Mark A. Pook
- Biosciences, School of Health Sciences & Social Care, Brunel University, Uxbridge, United Kingdom
| | - Gino A. Cortopassi
- Department of Molecular Biosciences, University of California, Davis, California
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Cnop M, Mulder H, Igoillo-Esteve M. Diabetes in Friedreich ataxia. J Neurochem 2013; 126 Suppl 1:94-102. [PMID: 23859345 DOI: 10.1111/jnc.12216] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 01/06/2013] [Indexed: 12/20/2022]
Abstract
Diabetes is a common metabolic disorder in patients with Friedreich ataxia. In this Supplement article, we review the clinical data on diabetes in Friedreich ataxia, and the experimental data from rodent and in vitro models of the disease. Increased body adiposity and insulin resistance are frequently present in Friedreich ataxia, but pancreatic β cell dysfunction and death are a conditio sine qua non for the loss of glucose tolerance and development of diabetes. The loss of frataxin function in mitochondria accounts for these pathogenic processes in Friedreich ataxia. Mitochondria are essential for the sensing of nutrients by the β cell and for the generation of signals that trigger and amplify insulin secretion, known as stimulus-secretion coupling. Moreover, in the intrinsic pathway of apoptosis, pro-apoptotic signals converge on mitochondria, resulting in mitochondrial Bax translocation, membrane permeabilization, cytochrome c release and caspase cleavage. How and at which level frataxin deficiency impacts on these processes in β cells is only partially understood. A better understanding of the molecular mechanisms mediating β cell demise in Friedreich ataxia will pave the way for new therapeutic approaches.
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Affiliation(s)
- Miriam Cnop
- Laboratory of Experimental Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Gomes CM, Santos R. Neurodegeneration in Friedreich's ataxia: from defective frataxin to oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:487534. [PMID: 23936609 PMCID: PMC3725840 DOI: 10.1155/2013/487534] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 06/14/2013] [Indexed: 02/08/2023]
Abstract
Friedreich's ataxia is the most common inherited autosomal recessive ataxia and is characterized by progressive degeneration of the peripheral and central nervous systems and cardiomyopathy. This disease is caused by the silencing of the FXN gene and reduced levels of the encoded protein, frataxin. Frataxin is a mitochondrial protein that functions primarily in iron-sulfur cluster synthesis. This small protein with an α / β sandwich fold undergoes complex processing and imports into the mitochondria, generating isoforms with distinct N-terminal lengths which may underlie different functionalities, also in respect to oligomerization. Missense mutations in the FXN coding region, which compromise protein folding, stability, and function, are found in 4% of FRDA heterozygous patients and are useful to understand how loss of functional frataxin impacts on FRDA physiopathology. In cells, frataxin deficiency leads to pleiotropic phenotypes, including deregulation of iron homeostasis and increased oxidative stress. Increasing amount of data suggest that oxidative stress contributes to neurodegeneration in Friedreich's ataxia.
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Affiliation(s)
- Cláudio M. Gomes
- Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2784-505 Oeiras, Portugal
| | - Renata Santos
- Development of the Nervous System, IBENS, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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Vaubel RA, Isaya G. Iron-sulfur cluster synthesis, iron homeostasis and oxidative stress in Friedreich ataxia. Mol Cell Neurosci 2013; 55:50-61. [PMID: 22917739 PMCID: PMC3530001 DOI: 10.1016/j.mcn.2012.08.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/01/2012] [Accepted: 08/05/2012] [Indexed: 12/21/2022] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive, multi-systemic degenerative disease that results from reduced synthesis of the mitochondrial protein frataxin. Frataxin has been intensely studied since its deficiency was linked to FRDA in 1996. The defining properties of frataxin - (i) the ability to bind iron, (ii) the ability to interact with, and donate iron to, other iron-binding proteins, and (iii) the ability to oligomerize, store iron and control iron redox chemistry - have been extensively characterized with different frataxin orthologs and their interacting protein partners. This very large body of biochemical and structural data [reviewed in (Bencze et al., 2006)] supports equally extensive biological evidence that frataxin is critical for mitochondrial iron metabolism and overall cellular iron homeostasis and antioxidant protection [reviewed in (Wilson, 2006)]. However, the precise biological role of frataxin remains a matter of debate. Here, we review seminal and recent data that strongly link frataxin to the synthesis of iron-sulfur cluster cofactors (ISC), as well as controversial data that nevertheless link frataxin to additional iron-related processes. Finally, we discuss how defects in ISC synthesis could be a major (although likely not unique) contributor to the pathophysiology of FRDA via (i) loss of ISC-dependent enzymes, (ii) mitochondrial and cellular iron dysregulation, and (iii) enhanced iron-mediated oxidative stress. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
- Rachael A Vaubel
- Department of Pediatric & Adolescent Medicine and the Mayo Clinic Children's Center, Mayo Clinic, Rochester, MN 55905, USA
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45
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Maresca A, la Morgia C, Caporali L, Valentino ML, Carelli V. The optic nerve: a "mito-window" on mitochondrial neurodegeneration. Mol Cell Neurosci 2013; 55:62-76. [PMID: 22960139 PMCID: PMC3629569 DOI: 10.1016/j.mcn.2012.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/27/2012] [Accepted: 08/06/2012] [Indexed: 01/16/2023] Open
Abstract
Retinal ganglion cells (RGCs) project their long axons, composing the optic nerve, to the brain, transmitting the visual information gathered by the retina, ultimately leading to formed vision in the visual cortex. The RGC cellular system, representing the anterior part of the visual pathway, is vulnerable to mitochondrial dysfunction and optic atrophy is a very frequent feature of mitochondrial and neurodegenerative diseases. The start of the molecular era of mitochondrial medicine, the year 1988, was marked by the identification of a maternally inherited form of optic atrophy, Leber's hereditary optic neuropathy, as the first disease due to mitochondrial DNA point mutations. The field of mitochondrial medicine has expanded enormously over the last two decades and many neurodegenerative diseases are now known to have a primary mitochondrial etiology or mitochondrial dysfunction plays a relevant role in their pathogenic mechanism. Recent technical advancements in neuro-ophthalmology, such as optical coherence tomography, prompted a still ongoing systematic re-investigation of retinal and optic nerve involvement in neurodegenerative disorders. In addition to inherited optic neuropathies, such as Leber's hereditary optic neuropathy and dominant optic atrophy, and in addition to the syndromic mitochondrial encephalomyopathies or mitochondrial neurodegenerative disorders such as some spinocerebellar ataxias or familial spastic paraparesis and other disorders, we draw attention to the involvement of the optic nerve in classic age-related neurodegenerative disorders such as Parkinson and Alzheimer disease. We here provide an overview of optic nerve pathology in these different clinical settings, and we review the possible mechanisms involved in the pathogenesis of optic atrophy. This may be a model of general value for the field of neurodegeneration. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
| | | | | | | | - Valerio Carelli
- Corresponding author at: IRCCS Institute of Neurological Sciences of Bologna, Department of Neurological Sciences, University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy. Fax: + 39 051 2092751.
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46
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Kovacic P, Somanathan R. Redox processes in neurodegenerative disease involving reactive oxygen species. Curr Neuropharmacol 2013; 10:289-302. [PMID: 23730253 PMCID: PMC3520039 DOI: 10.2174/157015912804143487] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 06/12/2012] [Accepted: 06/20/2012] [Indexed: 11/22/2022] Open
Abstract
Much attention has been devoted to neurodegenerative diseases involving redox processes. This review comprises an update involving redox processes reported in the considerable literature in recent years. The mechanism involves reactive oxygen species and oxidative stress, usually in the brain. There are many examples including Parkinson’s, Huntington’s, Alzheimer’s, prions, Down’s syndrome, ataxia, multiple sclerosis, Creutzfeldt-Jacob disease, amyotrophic lateral sclerosis, schizophrenia, and Tardive Dyskinesia. Evidence indicates a protective role for antioxidants, which may have clinical implications. A multifaceted approach to mode of action appears reasonable.
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Affiliation(s)
- Peter Kovacic
- Department of Chemistry and Biochemistry, San Diego State University, San Diego CA 92182 USA
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47
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Mandilaras K, Pathmanathan T, Missirlis F. Iron absorption in Drosophila melanogaster. Nutrients 2013; 5:1622-47. [PMID: 23686013 PMCID: PMC3708341 DOI: 10.3390/nu5051622] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/03/2013] [Accepted: 05/07/2013] [Indexed: 12/20/2022] Open
Abstract
The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration.
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Affiliation(s)
- Konstantinos Mandilaras
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK; E-Mail:
| | - Tharse Pathmanathan
- Department of Physiology, Biophysics and Neuroscience, CINVESTAV-IPN, IPN Avenue 2508, Zacatenco, 07360, Mexico City, Mexico; E-Mail:
| | - Fanis Missirlis
- Department of Physiology, Biophysics and Neuroscience, CINVESTAV-IPN, IPN Avenue 2508, Zacatenco, 07360, Mexico City, Mexico; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +52-55-5747-3963; Fax: +52-55-5747-5713
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48
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D’Oria V, Petrini S, Travaglini L, Priori C, Piermarini E, Petrillo S, Carletti B, Bertini E, Piemonte F. Frataxin deficiency leads to reduced expression and impaired translocation of NF-E2-related factor (Nrf2) in cultured motor neurons. Int J Mol Sci 2013; 14:7853-65. [PMID: 23574943 PMCID: PMC3645720 DOI: 10.3390/ijms14047853] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 03/29/2013] [Accepted: 04/02/2013] [Indexed: 11/22/2022] Open
Abstract
Oxidative stress has been implicated in the pathogenesis of Friedreich's Ataxia (FRDA), a neurodegenerative disease caused by the decreased expression of frataxin, a mitochondrial protein responsible of iron homeostasis. Under conditions of oxidative stress, the activation of the transcription factor NF-E2-related factor (Nrf2) triggers the antioxidant cellular response by inducing antioxidant response element (ARE) driven genes. Increasing evidence supports a role for the Nrf2-ARE pathway in neurodegenerative diseases. In this study, we analyzed the expression and the distribution of Nrf2 in silenced neurons for frataxin gene. Decreased Nrf2 mRNA content and a defective activation after treatment with pro-oxidants have been evidenced in frataxin-silenced neurons by RT-PCR and confocal microscopy. The loss of Nrf2 in FRDA may greatly enhance the cellular susceptibility to oxidative stress and make FRDA neurons more vulnerable to injury. Our findings may help to focus on this promising target, especially in its emerging role in the neuroprotective response.
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Affiliation(s)
- Valentina D’Oria
- Confocal Microscopy Core Facility, Research Laboratories, Bambino Gesù Children’s Hospital, IRCCS, Rome 00165, Italy; E-Mails: (V.D.); (S.P.)
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, Bambino Gesù Children’s Hospital, IRCCS, Rome 00165, Italy; E-Mails: (V.D.); (S.P.)
| | - Lorena Travaglini
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
| | - Chiara Priori
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
| | - Emanuela Piermarini
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
| | - Sara Petrillo
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
| | - Barbara Carletti
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
| | - Enrico Bertini
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
| | - Fiorella Piemonte
- Unit for Neuromuscular and Neurodegenerative Diseases, Bambino Gesù Children’s Hospital, IRCCS, Piazza S’Onofrio, 4, Rome 00165, Italy; E-Mails: (L.T.); (C.P.); (E.P.); (S.P.); (B.C.); (E.B.)
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Landry AP, Cheng Z, Ding H. Iron binding activity is essential for the function of IscA in iron-sulphur cluster biogenesis. Dalton Trans 2013; 42:3100-6. [PMID: 23258274 PMCID: PMC3569480 DOI: 10.1039/c2dt32000b] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Iron-sulphur cluster biogenesis requires coordinated delivery of iron and sulphur to scaffold proteins, followed by transfer of the assembled clusters from scaffold proteins to target proteins. This complex process is accomplished by a group of dedicated iron-sulphur cluster assembly proteins that are conserved from bacteria to humans. While sulphur in iron-sulphur clusters is provided by L-cysteine via cysteine desulfurase, the iron donor(s) for iron-sulphur cluster assembly remains largely elusive. Here we report that among the primary iron-sulphur cluster assembly proteins, IscA has a unique and strong binding activity for mononuclear iron in vitro and in vivo. Furthermore, the ferric iron centre tightly bound in IscA can be readily extruded by l-cysteine, followed by reduction to ferrous iron for iron-sulphur cluster biogenesis. Substitution of the highly conserved residue tyrosine 40 with phenylalanine (Y40F) in IscA results in a mutant protein that has a diminished iron binding affinity but retains the iron-sulphur cluster binding activity. Genetic complementation studies show that the IscA Y40F mutant is inactive in vivo, suggesting that the iron binding activity is essential for the function of IscA in iron-sulphur cluster biogenesis.
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Affiliation(s)
- Aaron P Landry
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Uhrigshardt H, Rouault TA, Missirlis F. Insertion mutants in Drosophila melanogaster Hsc20 halt larval growth and lead to reduced iron-sulfur cluster enzyme activities and impaired iron homeostasis. J Biol Inorg Chem 2013; 18:441-9. [PMID: 23444034 PMCID: PMC3612401 DOI: 10.1007/s00775-013-0988-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 02/07/2013] [Indexed: 10/31/2022]
Abstract
Despite the prominence of iron-sulfur cluster (ISC) proteins in bioenergetics, intermediary metabolism, and redox regulation of cellular, mitochondrial, and nuclear processes, these proteins have been given scarce attention in Drosophila. Moreover, biosynthesis and delivery of ISCs to target proteins requires a highly regulated molecular network that spans different cellular compartments. The only Drosophila ISC biosynthetic protein studied to date is frataxin, in attempts to model Friedreich's ataxia, a disease arising from reduced expression of the human frataxin homologue. One of several proteins involved in ISC biogenesis is heat shock protein cognate 20 (Hsc20). Here we characterize two piggyBac insertion mutants in Drosophila Hsc20 that display larval growth arrest and deficiencies in aconitase and succinate dehydrogenase activities, but not in isocitrate dehydrogenase activity; phenotypes also observed with ubiquitous frataxin RNA interference. Furthermore, a disruption of iron homeostasis in the mutant flies was evidenced by an apparent reduction in induction of intestinal ferritin with ferric iron accumulating in a subcellular pattern reminiscent of mitochondria. These phenotypes were specific to intestinal cell types that regulate ferritin expression, but were notably absent in the iron cells where ferritin is constitutively expressed and apparently translated independently of iron regulatory protein 1A. Hsc20 mutant flies represent an independent tool to disrupt ISC biogenesis in vivo without using the RNA interference machinery.
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Affiliation(s)
- Helge Uhrigshardt
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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