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Lu L, Jifu C, Xia J, Wang J. E3 ligases and DUBs target ferroptosis: A potential therapeutic strategy for neurodegenerative diseases. Biomed Pharmacother 2024; 175:116753. [PMID: 38761423 DOI: 10.1016/j.biopha.2024.116753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/30/2024] [Accepted: 05/10/2024] [Indexed: 05/20/2024] Open
Abstract
Ferroptosis is a form of cell death mediated by iron and lipid peroxidation (LPO). Recent studies have provided compelling evidence to support the involvement of ferroptosis in the pathogenesis of various neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD). Therefore, understanding the mechanisms that regulate ferroptosis in NDDs may improve disease management. Ferroptosis is regulated by multiple mechanisms, and different degradation pathways, including autophagy and the ubiquitinproteasome system (UPS), orchestrate the complex ferroptosis response by directly or indirectly regulating iron accumulation or lipid peroxidation. Ubiquitination plays a crucial role as a protein posttranslational modification in driving ferroptosis. Notably, E3 ubiquitin ligases (E3s) and deubiquitinating enzymes (DUBs) are key enzymes in the ubiquitin system, and their dysregulation is closely linked to the progression of NDDs. A growing body of evidence highlights the role of ubiquitin system enzymes in regulating ferroptosis sensitivity. However, reports on the interaction between ferroptosis and ubiquitin signaling in NDDs are scarce. In this review, we first provide a brief overview of the biological processes and roles of the UPS, summarize the core molecular mechanisms and potential biological functions of ferroptosis, and explore the pathophysiological relevance and therapeutic implications of ferroptosis in NDDs. In addition, reviewing the roles of E3s and DUBs in regulating ferroptosis in NDDs aims to provide new insights and strategies for the treatment of NDDs. These include E3- and DUB-targeted drugs and ferroptosis inhibitors, which can be used to prevent and ameliorate the progression of NDDs.
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Affiliation(s)
- Linxia Lu
- College of Basic Medicine, Jiamusi University, Jiamusi 154007, People's Republic of China
| | - Cili Jifu
- College of Basic Medicine, Jiamusi University, Jiamusi 154007, People's Republic of China
| | - Jun Xia
- College of Basic Medicine, Jiamusi University, Jiamusi 154007, People's Republic of China
| | - Jingtao Wang
- College of Basic Medicine, Jiamusi University, Jiamusi 154007, People's Republic of China.
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Grander M, Haschka D, Indelicato E, Kremser C, Amprosi M, Nachbauer W, Henninger B, Stefani A, Högl B, Fischer C, Seifert M, Kiechl S, Weiss G, Boesch S. Genetic Determined Iron Starvation Signature in Friedreich's Ataxia. Mov Disord 2024. [PMID: 38686449 DOI: 10.1002/mds.29819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/02/2024] [Accepted: 04/09/2024] [Indexed: 05/02/2024] Open
Abstract
BACKGROUND Early studies in cellular models suggested an iron accumulation in Friedreich's ataxia (FA), yet findings from patients are lacking. OBJECTIVES The objective is to characterize systemic iron metabolism, body iron storages, and intracellular iron regulation in FA patients. METHODS In FA patients and matched healthy controls, we assessed serum iron parameters, regulatory hormones as well as the expression of regulatory proteins and iron distribution in peripheral blood mononuclear cells (PBMCs). We applied magnetic resonance imaging with R2*-relaxometry to quantify iron storages in the liver, spleen, and pancreas. Across all evaluations, we assessed the influence of the genetic severity as expressed by the length of the shorter GAA-expansion (GAA1). RESULTS We recruited 40 FA patients (19 women). Compared to controls, FA patients displayed lower serum iron and transferrin saturation. Serum ferritin, hepcidin, mean corpuscular hemoglobin and mean corpuscular volume in FA inversely correlated with the GAA1-repeat length, indicating iron deficiency and restricted availability for erythropoiesis with increasing genetic severity. R2*-relaxometry revealed a reduction of splenic and hepatic iron stores in FA. Liver and spleen R2* values inversely correlated with the GAA1-repeat length. FA PBMCs displayed downregulation of ferritin and upregulation of transferrin receptor and divalent metal transporter-1 mRNA, particularly in patients with >500 GAA1-repeats. In FA PBMCs, intracellular iron was not increased, but shifted toward mitochondria. CONCLUSIONS We provide evidence for a previously unrecognized iron starvation signature at systemic and cellular levels in FA patients, which is related to the underlying genetic severity. These findings challenge the use of systemic iron lowering therapies in FA. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Manuel Grander
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - David Haschka
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Elisabetta Indelicato
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christian Kremser
- Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Matthias Amprosi
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Wolfgang Nachbauer
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Benjamin Henninger
- Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ambra Stefani
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Birgit Högl
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Christine Fischer
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Markus Seifert
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Kiechl
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
- VASCage, Centre on Clinical Stroke Research, Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, Austria
| | - Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Liu J, Chen H, Lin H, Peng S, Chen L, Cheng X, Yao P, Tang Y. Iron-frataxin involved in the protective effect of quercetin against alcohol-induced liver mitochondrial dysfunction. J Nutr Biochem 2023; 114:109258. [PMID: 36587874 DOI: 10.1016/j.jnutbio.2022.109258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 12/17/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022]
Abstract
Emerging evidence supports the beneficial effect of quercetin on liver mitochondrial disorders. However, the molecular mechanism by which quercetin protects mitochondria is limited, especially in alcoholic liver disease. In this study, C57BL/6N mice were fed with Lieber De Carli liquid diet (28% ethanol-derived calories) for 12 weeks plus a single binge ethanol and intervened with quercetin (100 mg/kg.bw). Moreover, HepG2CYP2E1+/+ were stimulated with ethanol (100 mM) and quercetin (50 µM) to investigate the effects of mitochondrial protein frataxin. The results indicated that quercetin alleviated alcohol-induced histopathological changes and mitochondrial functional disorders in mice livers. Consistent with increased PINK1, Parkin, Bnip3 and LC3II as well as decreased p62, TOM20 and VDAC1 expression, the inhibition of mitophagy by ethanol was blocked by quercetin. Additionally, quercetin improved the imbalance of iron metabolism-related proteins expression in alcohol-fed mice livers. Compared with ethanol-treated Lv-empty HepG2CYP2E1+/+ cells, frataxin deficiency further exacerbated the inhibition of mitochondrial function. Conversely, restoration of frataxin expression ameliorated the effect of ethanol. Furthermore, frataxin deficiency reduced the protective effects of quercetin on mitochondria disordered by ethanol. Attentively, ferric ammonium citrate (FAC) and deferiprone decreased or increased frataxin expression in HepG2CYP2E1+/+, respectively. Notably, we further found FAC reversed the increasing effect of quercetin on frataxin expression. Ultimately, silencing NCOA4 attenuated the inhibition of quercetin on LDH release and mitochondrial membrane potential increase, and similar results were observed by adding FAC. Collectively, these findings demonstrated quercetin increased frataxin expression through regulating iron level, thereby mitigating ethanol-induced mitochondrial dysfunction.
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Affiliation(s)
- Jingjing Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Henan Center for Disease Control and Prevention, Zhengzhou 450016, China
| | - Huimin Chen
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hongkun Lin
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shufen Peng
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Li Chen
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xueer Cheng
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ping Yao
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yuhan Tang
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Kalef-Ezra E, Edzeamey FJ, Valle A, Khonsari H, Kleine P, Oggianu C, Al-Mahdawi S, Pook MA, Anjomani Virmouni S. A new FRDA mouse model [ Fxn null:YG8s(GAA) > 800] with more than 800 GAA repeats. Front Neurosci 2023; 17:930422. [PMID: 36777637 PMCID: PMC9909538 DOI: 10.3389/fnins.2023.930422] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 01/04/2023] [Indexed: 01/27/2023] Open
Abstract
Introduction Friedreich's ataxia (FRDA) is an inherited recessive neurodegenerative disorder caused by a homozygous guanine-adenine-adenine (GAA) repeat expansion within intron 1 of the FXN gene, which encodes the essential mitochondrial protein frataxin. There is still no effective therapy for FRDA, therefore the development of optimal cell and animal models of the disease is one of the priorities for preclinical therapeutic testing. Methods We obtained the latest FRDA humanized mouse model that was generated on the basis of our previous YG8sR, by Jackson laboratory [YG8JR, Fxn null:YG8s(GAA) > 800]. We characterized the behavioral, cellular, molecular and epigenetics properties of the YG8JR model, which has the largest GAA repeat sizes compared to all the current FRDA mouse models. Results We found statistically significant behavioral deficits, together with reduced levels of frataxin mRNA and protein, and aconitase activity in YG8JR mice compared with control Y47JR mice. YG8JR mice exhibit intergenerational GAA repeat instability by the analysis of parent and offspring tissue samples. Somatic GAA repeat instability was also detected in individual brain and cerebellum tissue samples. In addition, increased DNA methylation of CpG U13 was identified in FXN GAA repeat region in the brain, cerebellum, and heart tissues. Furthermore, we show decreased histone H3K9 acetylation and increased H3K9 methylation of YG8JR cerebellum tissues within the FXN gene, upstream and downstream of the GAA repeat region compared to Y47JR controls. Discussion These studies provide a detailed characterization of the GAA repeat expansion-based YG8JR transgenic mouse models that will help investigations of FRDA disease mechanisms and therapy.
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Affiliation(s)
- Ester Kalef-Ezra
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Fred Jonathan Edzeamey
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Adamo Valle
- Energy Metabolism and Nutrition, Research Institute of Health Sciences (IUNICS), University of Balearic Islands, Palma, Spain,Health Research Institute of Balearic Islands (IdISBa), Palma, Spain,Biomedical Research Networking Center for Physiopathology of Obesity and Nutrition (CIBERobn CB06/03/0043), Instituto de Salud Carlos III, Madrid, Spain
| | - Hassan Khonsari
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Paula Kleine
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Carlo Oggianu
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Sahar Al-Mahdawi
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Mark A. Pook
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Sara Anjomani Virmouni
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, Brunel University London, Uxbridge, United Kingdom,*Correspondence: Sara Anjomani Virmouni,
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Profeta V, McIntyre K, Wells M, Park C, Lynch DR. Omaveloxolone: an activator of Nrf2 for the treatment of Friedreich ataxia. Expert Opin Investig Drugs 2023; 32:5-16. [PMID: 36708320 DOI: 10.1080/13543784.2023.2173063] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
INTRODUCTION Friedreich ataxia (FRDA) is a rare autosomal recessive degenerative disorder characterized by ataxia, dysarthria, diabetes, cardiomyopathy, scoliosis, and occasionally vision loss in late-stage disease. The discovery of the abnormal gene in FRDA and its product frataxin has provided insight into the pathophysiology and mechanisms of treatment. AREAS COVERED Although the neurologic phenotype of FRDA is well defined, there are currently no established pharmacological treatments. Omaveloxolone, a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, is currently under review by the Food and Drug Administration (FDA) and has the potential to be the first approved treatment for FRDA. In the present report, we have reviewed the basic and clinical literature on Nrf2 deficiency in FRDA, and evidence for the benefit of omaveloxolone. EXPERT OPINION The present perspective suggests that omaveloxolone is a rational and efficacious therapy that is possibly disease modifying in treatment of FRDA.
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Affiliation(s)
- Victoria Profeta
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kellie McIntyre
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - McKenzie Wells
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Courtney Park
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David R Lynch
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Keita M, McIntyre K, Rodden LN, Schadt K, Lynch DR. Friedreich ataxia: clinical features and new developments. Neurodegener Dis Manag 2022; 12:267-283. [PMID: 35766110 PMCID: PMC9517959 DOI: 10.2217/nmt-2022-0011] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 06/15/2022] [Indexed: 11/21/2022] Open
Abstract
Friedreich's ataxia (FRDA), a neurodegenerative disease characterized by ataxia and other neurological features, affects 1 in 50,000-100,000 individuals in the USA. However, FRDA also includes cardiac, orthopedic and endocrine dysfunction, giving rise to many secondary disease characteristics. The multifaceted approach for clinical care has necessitated the development of disease-specific clinical care guidelines. New developments in FRDA include the advancement of clinical drug trials targeting the NRF2 pathway and frataxin restoration. Additionally, a novel understanding of gene silencing in FRDA, reflecting a variegated silencing pattern, will have applications to current and future therapeutic interventions. Finally, new perspectives on the neuroanatomy of FRDA and its developmental features will refine the time course and anatomical targeting of novel approaches.
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Affiliation(s)
- Medina Keita
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kellie McIntyre
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Layne N Rodden
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kim Schadt
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David R Lynch
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Mandal AK. Mitochondrial targeting of potent nanoparticulated drugs in combating diseases. J Biomater Appl 2022; 37:614-633. [PMID: 35790487 DOI: 10.1177/08853282221111656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Mitochondrial dysfunction, characterized by the electron transport chain (ETC) leakage and reduced adenosine tri-phosphate synthesis, occurs primarily due to free radicals -induced mutations in either the mitochondrial deoxyribonucleic acid (mtDNA) or nuclear (n) DNA caused by pathogenic infections, toxicant exposures, adverse drug-effects, or other environmental exposures, leading to secondary dysfunction affecting ischemic, diabetic, cancerous, and degenerative diseases. In these concerns, mitochondria-targeted remedies may include a significant role in the protection and treatment of mitochondrial function to enhance its activity. Coenzyme Q10 pyridinol and pyrimidinol antioxidant analogues and other potent drug-compounds for their multifunctional radical quencher and other anti-toxic activities may take a significant therapeutic effectivity for ameliorating mitochondrial dysfunction. Moreover, the encapsulation of these bioactive ligands-attached potent compounds in vesicular system may enable them a superb biological effective for the treatment of mitochondria-targeted dysfunction-related diseases with least side effects. This review depicts mainly on mitochondrial enzymatic dysfunction and their amelioration by potent drugs with the usages of nanoparticulated delivery system against mitochondria-affected diseases.
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Hackett PT, Jia X, Li L, Ward DM. Posttranslational regulation of mitochondrial frataxin and identification of compounds that increase frataxin levels in Friedreich's ataxia. J Biol Chem 2022; 298:101982. [PMID: 35472330 PMCID: PMC9127368 DOI: 10.1016/j.jbc.2022.101982] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 04/18/2022] [Accepted: 04/19/2022] [Indexed: 11/18/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a degenerative disease caused by a decrease in the mitochondrial protein frataxin (Fxn), which is involved in iron-sulfur cluster (ISC) synthesis. Diminutions in Fxn result in decreased ISC synthesis, increased mitochondrial iron accumulation, and impaired mitochondrial function. Here, we show that conditions that result in increased mitochondrial reactive oxygen species in yeast or mammalian cell culture give rise to increased turnover of Fxn but not of other ISC synthesis proteins. We demonstrate that the mitochondrial Lon protease is involved in Fxn degradation and that iron export through the mitochondrial metal transporter Mmt1 protects yeast Fxn from degradation. We also determined that when FRDA fibroblasts were grown in media containing elevated iron, mitochondrial reactive oxygen species increased and Fxn decreased compared to WT fibroblasts. Furthermore, we screened a library of FDA-approved compounds and identified 38 compounds that increased yeast Fxn levels, including the azole bifonazole, antiparasitic fipronil, antitumor compound dibenzoylmethane, antihypertensive 4-hydroxychalcone, and a nonspecific anion channel inhibitor 4,4-diisothiocyanostilbene-2,2-sulfonic acid. We show that top hits 4-hydroxychalcone and dibenzoylmethane increased mRNA levels of transcription factor nuclear factor erythroid 2-related factor 2 in FRDA patient-derived fibroblasts, as well as downstream antioxidant targets thioredoxin, glutathione reductase, and superoxide dismutase 2. Taken together, these findings reveal that FRDA progression may be in part due to oxidant-mediated decreases in Fxn and that some approved compounds may be effective in increasing mitochondrial Fxn in FRDA, delaying disease progression.
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Affiliation(s)
- Peter T Hackett
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Xuan Jia
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Liangtao Li
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Diane M Ward
- Department of Pathology, Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, Utah, USA.
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Campos OA, Attar N, Cheng C, Vogelauer M, Mallipeddi NV, Schmollinger S, Matulionis N, Christofk HR, Merchant SS, Kurdistani SK. A pathogenic role for histone H3 copper reductase activity in a yeast model of Friedreich's ataxia. SCIENCE ADVANCES 2021; 7:eabj9889. [PMID: 34919435 PMCID: PMC8682991 DOI: 10.1126/sciadv.abj9889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
Disruptions to iron-sulfur (Fe-S) clusters, essential cofactors for a broad range of proteins, cause widespread cellular defects resulting in human disease. A source of damage to Fe-S clusters is cuprous (Cu1+) ions. Since histone H3 enzymatically produces Cu1+ for copper-dependent functions, we asked whether this activity could become detrimental to Fe-S clusters. Here, we report that histone H3–mediated Cu1+ toxicity is a major determinant of cellular functional pool of Fe-S clusters. Inadequate Fe-S cluster supply, due to diminished assembly as occurs in Friedreich’s ataxia or defective distribution, causes severe metabolic and growth defects in Saccharomyces cerevisiae. Decreasing Cu1+ abundance, through attenuation of histone cupric reductase activity or depletion of total cellular copper, restored Fe-S cluster–dependent metabolism and growth. Our findings reveal an interplay between chromatin and mitochondria in Fe-S cluster homeostasis and a potential pathogenic role for histone enzyme activity and Cu1+ in diseases with Fe-S cluster dysfunction.
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Affiliation(s)
- Oscar A. Campos
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Narsis Attar
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Chen Cheng
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Maria Vogelauer
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Nathan V. Mallipeddi
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | - Nedas Matulionis
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Heather R. Christofk
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Sabeeha S. Merchant
- QB3-Berkeley, University of California, Berkeley, Berkeley, CA 94720, USA
- Departments of Molecular and Cell Biology and Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Siavash K. Kurdistani
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
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Dietz JV, Fox JL, Khalimonchuk O. Down the Iron Path: Mitochondrial Iron Homeostasis and Beyond. Cells 2021; 10:cells10092198. [PMID: 34571846 PMCID: PMC8468894 DOI: 10.3390/cells10092198] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/22/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
Abstract
Cellular iron homeostasis and mitochondrial iron homeostasis are interdependent. Mitochondria must import iron to form iron–sulfur clusters and heme, and to incorporate these cofactors along with iron ions into mitochondrial proteins that support essential functions, including cellular respiration. In turn, mitochondria supply the cell with heme and enable the biogenesis of cytosolic and nuclear proteins containing iron–sulfur clusters. Impairment in cellular or mitochondrial iron homeostasis is deleterious and can result in numerous human diseases. Due to its reactivity, iron is stored and trafficked through the body, intracellularly, and within mitochondria via carefully orchestrated processes. Here, we focus on describing the processes of and components involved in mitochondrial iron trafficking and storage, as well as mitochondrial iron–sulfur cluster biogenesis and heme biosynthesis. Recent findings and the most pressing topics for future research are highlighted.
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Affiliation(s)
- Jonathan V. Dietz
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
| | - Jennifer L. Fox
- Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424, USA;
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
- Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
- Fred and Pamela Buffett Cancer Center, Omaha, NE 68198, USA
- Correspondence:
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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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12
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Liu J, Bandyopadhyay I, Zheng L, Khdour OM, Hecht SM. Antiferroptotic Activity of Phenothiazine Analogues: A Novel Therapeutic Strategy for Oxidative Stress Related Disease. ACS Med Chem Lett 2020; 11:2165-2173. [PMID: 33214825 DOI: 10.1021/acsmedchemlett.0c00293] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Ferroptosis is an iron-catalyzed, nonapoptotic form of regulated necrosis that has been implicated in the pathological cell death associated with various disorders including neurodegenerative diseases (e.g., Friedreich's ataxia (FRDA), Alzheimer's disease, and Parkinson's disease), stroke, and traumatic brain injury. Recently, we showed that lipophilic methylene blue (MB) and methylene violet (MV) analogues both promoted increased frataxin levels and mitochondrial biogenesis, in addition to their antioxidant activity in cultured FRDA cells. Presently, we report the synthesis of series of lipophilic phenothiazine analogues that potently inhibit ferroptosis. The most promising compounds (1b-5b) exhibited an improved protection compared to the parent phenothiazine against erastin- and RSL3-induced ferroptotic cell death. These analogues have equivalent or better potency than ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1), that are among the most potent inhibitors of this regulated cell death described so far. They represent novel lead compounds with therapeutic potential in relevant ferroptosis-driven disease models such as FRDA.
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13
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The Nrf2 induction prevents ferroptosis in Friedreich's Ataxia. Redox Biol 2020; 38:101791. [PMID: 33197769 PMCID: PMC7677700 DOI: 10.1016/j.redox.2020.101791] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/14/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022] Open
Abstract
Ferroptosis is an iron-dependent cell death caused by impaired glutathione metabolism, lipid peroxidation and mitochondrial failure. Emerging evidences report a role for ferroptosis in Friedreich's Ataxia (FRDA), a neurodegenerative disease caused by the decreased expression of the mitochondrial protein frataxin. Nrf2 signalling is implicated in many molecular aspects of ferroptosis, by upstream regulating glutathione homeostasis, mitochondrial function and lipid metabolism. As Nrf2 is down-regulated in FRDA, targeting Nrf2-mediated ferroptosis in FRDA may be an attractive option to counteract neurodegeneration in such disease, thus paving the way to new therapeutic opportunities. In this study, we evaluated ferroptosis hallmarks in frataxin-silenced mouse myoblasts, in hearts of a frataxin Knockin/Knockout (KIKO) mouse model, in skin fibroblasts and blood of patients, particularly focusing on ferroptosis-driven gene expression, mitochondrial impairment and lipid peroxidation. The efficacy of Nrf2 inducers to neutralize ferroptosis has been also evaluated.
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14
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The NRF2 Signaling Network Defines Clinical Biomarkers and Therapeutic Opportunity in Friedreich's Ataxia. Int J Mol Sci 2020; 21:ijms21030916. [PMID: 32019240 PMCID: PMC7037688 DOI: 10.3390/ijms21030916] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/27/2020] [Accepted: 01/29/2020] [Indexed: 02/06/2023] Open
Abstract
Friedreich’s ataxia (FA) is a trinucleotide repeats expansion neurodegenerative disorder, for which no cure or approved therapies are present. In most cases, GAA trinucleotide repetitions in the first intron of the FXN gene are the genetic trigger of FA, determining a strong reduction of frataxin, a mitochondrial protein involved in iron homeostasis. Frataxin depletion impairs iron–sulfur cluster biosynthesis and determines iron accumulation in the mitochondria. Mounting evidence suggests that these defects increase oxidative stress susceptibility and reactive oxygen species production in FA, where the pathologic picture is worsened by a defective regulation of the expression and signaling pathway modulation of the transcription factor NF-E2 p45-related factor 2 (NRF2), one of the fundamental mediators of the cellular antioxidant response. NRF2 protein downregulation and impairment of its nuclear translocation can compromise the adequate cellular response to the frataxin depletion-dependent redox imbalance. As NRF2 stability, expression, and activation can be modulated by diverse natural and synthetic compounds, efforts have been made in recent years to understand if regulating NRF2 signaling might ameliorate the pathologic defects in FA. Here we provide an analysis of the pharmaceutical interventions aimed at restoring the NRF2 signaling network in FA, elucidating specific biomarkers useful for monitoring therapeutic effectiveness, and developing new therapeutic tools.
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15
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Sacchetto C, Sequeira V, Bertero E, Dudek J, Maack C, Calore M. Metabolic Alterations in Inherited Cardiomyopathies. J Clin Med 2019; 8:jcm8122195. [PMID: 31842377 PMCID: PMC6947282 DOI: 10.3390/jcm8122195] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 12/12/2022] Open
Abstract
The normal function of the heart relies on a series of complex metabolic processes orchestrating the proper generation and use of energy. In this context, mitochondria serve a crucial role as a platform for energy transduction by supplying ATP to the varying demand of cardiomyocytes, involving an intricate network of pathways regulating the metabolic flux of substrates. The failure of these processes results in structural and functional deficiencies of the cardiac muscle, including inherited cardiomyopathies. These genetic diseases are characterized by cardiac structural and functional anomalies in the absence of abnormal conditions that can explain the observed myocardial abnormality, and are frequently associated with heart failure. Since their original description, major advances have been achieved in the genetic and phenotype knowledge, highlighting the involvement of metabolic abnormalities in their pathogenesis. This review provides a brief overview of the role of mitochondria in the energy metabolism in the heart and focuses on metabolic abnormalities, mitochondrial dysfunction, and storage diseases associated with inherited cardiomyopathies.
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Affiliation(s)
- Claudia Sacchetto
- IMAiA—Institute for Molecular Biology and RNA Technology, Faculty of Health, Universiteitssingel 50, 6229ER Maastricht, The Netherlands;
- Medicine and Life Sciences, Faculty of Science and Engineering, Universiteitssingel 50, 6229ER Maastricht, The Netherlands
- Department of Biology, University of Padova, via Ugo Bassi 58B, 35121 Padova, Italy
| | - Vasco Sequeira
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Edoardo Bertero
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Jan Dudek
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
| | - Christoph Maack
- Department of Translational Science, Comprehensive Heart Failure Center, University Clinic Würzburg, Am Schwarzenberg 15, 9708 Würzburg, Germany; (V.S.); (E.B.); (J.D.)
- Correspondence: (C.M.); (M.C.)
| | - Martina Calore
- IMAiA—Institute for Molecular Biology and RNA Technology, Faculty of Health, Universiteitssingel 50, 6229ER Maastricht, The Netherlands;
- Medicine and Life Sciences, Faculty of Science and Engineering, Universiteitssingel 50, 6229ER Maastricht, The Netherlands
- Correspondence: (C.M.); (M.C.)
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Delatycki MB, Bidichandani SI. Friedreich ataxia- pathogenesis and implications for therapies. Neurobiol Dis 2019; 132:104606. [PMID: 31494282 DOI: 10.1016/j.nbd.2019.104606] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/08/2019] [Accepted: 09/04/2019] [Indexed: 01/01/2023] Open
Abstract
Friedreich ataxia is the most common of the hereditary ataxias. It is due to homozygous/compound heterozygous mutations in FXN. This gene encodes frataxin, a protein largely localized to mitochondria. In about 96% of affected individuals there is homozygosity for a GAA repeat expansion in intron 1 of the FXN gene. Studies of people with Friedreich ataxia and of animal and cell models, have provided much insight into the pathogenesis of this disorder. The expanded GAA repeat leads to transcriptional deficiency of the FXN gene. The consequent deficiency of frataxin protein leads to reduced iron-sulfur cluster biogenesis and mitochondrial ATP production, elevated mitochondrial iron, and oxidative stress. More recently, a role for inflammation has emerged as being important in the pathogenesis of Friedreich ataxia. These findings have led to a number of potential therapies that have been subjected to clinical trials or are being developed toward human studies. Therapies that have been proposed include pharmaceuticals that increase frataxin levels, protein and gene replacement therapies, antioxidants, iron chelators and modulators of inflammation. Whilst no therapies have yet been approved for Friedreich ataxia, there is much optimism that the advances in the understanding of the pathogenesis of this disorder since the discovery its genetic basis, will result in approved disease modifying therapies in the near future.
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Affiliation(s)
- Martin B Delatycki
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, Victoria, Australia; Victorian Clinical Genetics Services, Parkville, Victoria, Australia; Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.
| | - Sanjay I Bidichandani
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Clay A, Hearle P, Schadt K, Lynch DR. New developments in pharmacotherapy for Friedreich ataxia. Expert Opin Pharmacother 2019; 20:1855-1867. [PMID: 31311349 DOI: 10.1080/14656566.2019.1639671] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Friedreich ataxia (FRDA), a rare disease caused by the deficiency of the mitochondrial matrix protein frataxin, affects roughly 1 in 50,000 individuals worldwide. Current and emerging therapies focus on reversing the deleterious effects of such deficiency including mitochondrial augmentation and increasing frataxin levels, providing the possibility of treatment options for this physiologically complex, multisystem disorder. Areas covered: In this review article, the authors discuss the current and prior in vivo and in vitro research studies related to the treatment of FRDA, with a particular interest in future implications of each therapy. Expert opinion: Since the discovery of FXN in 1996, multiple clinical trials have occurred or are currently occurring; at a rapid pace for a rare disease. These trials have been directed at the augmentation of mitochondrial function and/or alleviation of symptoms and are not regarded as potential cures in FRDA. Either a combination of therapies or a drug that replaces or increases the pathologically low levels of frataxin better represent potential cures in FRDA.
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Affiliation(s)
- Alexandra Clay
- Division of Neurology, Children's Hospital of Philadelphia , Philadelphia , PA , USA
| | - Patrick Hearle
- Division of Neurology, Children's Hospital of Philadelphia , Philadelphia , PA , USA
| | - Kim Schadt
- Division of Neurology, Children's Hospital of Philadelphia , Philadelphia , PA , USA
| | - David R Lynch
- Division of Neurology, Children's Hospital of Philadelphia , Philadelphia , PA , USA
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18
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Jasoliya M, Sacca F, Sahdeo S, Chedin F, Pane C, Brescia Morra V, Filla A, Pook M, Cortopassi G. Dimethyl fumarate dosing in humans increases frataxin expression: A potential therapy for Friedreich's Ataxia. PLoS One 2019; 14:e0217776. [PMID: 31158268 PMCID: PMC6546270 DOI: 10.1371/journal.pone.0217776] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/18/2019] [Indexed: 11/19/2022] Open
Abstract
Friedreich's Ataxia (FA) is an inherited neurodegenerative disorder resulting from decreased expression of the mitochondrial protein frataxin, for which there is no approved therapy. High throughput screening of clinically used drugs identified Dimethyl fumarate (DMF) as protective in FA patient cells. Here we demonstrate that DMF significantly increases frataxin gene (FXN) expression in FA cell model, FA mouse model and in DMF treated humans. DMF also rescues mitochondrial biogenesis deficiency in FA-patient derived cell model. We further examined the mechanism of DMF's frataxin induction in FA patient cells. It has been shown that transcription-inhibitory R-loops form at GAA expansion mutations, thus decreasing FXN expression. In FA patient cells, we demonstrate that DMF significantly increases transcription initiation. As a potential consequence, we observe significant reduction in both R-loop formation and transcriptional pausing thereby significantly increasing FXN expression. Lastly, DMF dosed Multiple Sclerosis (MS) patients showed significant increase in FXN expression by ~85%. Since inherited deficiency in FXN is the primary cause of FA, and DMF is demonstrated to increase FXN expression in humans, DMF could be considered for Friedreich's therapy.
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Affiliation(s)
- Mittal Jasoliya
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Francesco Sacca
- Department of Neurosciences, Odontostomatological and Reproductive Sciences, University Federico II, Naples, Italy
| | - Sunil Sahdeo
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Frederic Chedin
- Department of Molecular and Cellular Biology, University of California, Davis, California, United States of America
| | - Chiara Pane
- Department of Neurosciences, Odontostomatological and Reproductive Sciences, University Federico II, Naples, Italy
| | - Vincenzo Brescia Morra
- Department of Neurosciences, Odontostomatological and Reproductive Sciences, University Federico II, Naples, Italy
| | - Alessandro Filla
- Department of Neurosciences, Odontostomatological and Reproductive Sciences, University Federico II, Naples, Italy
| | - Mark Pook
- Department of Life Sciences, College of Health & Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Gino Cortopassi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, California, United States of America
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Cook A, Boesch S, Heck S, Brunt E, Klockgether T, Schöls L, Schulz A, Giunti P. Patient-reported outcomes in Friedreich's ataxia after withdrawal from idebenone. Acta Neurol Scand 2019; 139:533-539. [PMID: 30887496 DOI: 10.1111/ane.13088] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 03/07/2019] [Accepted: 03/12/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Friedreich's ataxia is the most common inherited ataxia, and pathogenesis is known to involve mitochondrial oxidative stress. Idebenone is a potent antioxidant which has already been evaluated in several clinical trials in FRDA, with reports of symptomatic benefit but inconclusive objective results. Following patient consultation on design, we have completed a treatment-withdrawal study to establish whether patients could correctly determine their treatment allocation to placebo or idebenone. Our aim was to capture subjective experiences of symptoms such as fatigue, which can be difficult to measure with questionnaires or semi-quantitative scales, particularly in chronic, slowly progressive conditions. MATERIALS AND METHODS Patients taking idebenone for at least 12 months as part of the open-label MICONOS Extension Study were randomized to receive either placebo or idebenone continuation for 2-month treatment cycles. The primary endpoint was patient assessment of treatment assignment. RESULTS A total of 29 patients were randomized, forming the idebenone group (n = 16) and the placebo group (n = 13). No significant differences were detected between the idebenone and placebo groups on assessment of treatment assignment or early study withdrawal. A small but significant difference in ataxia rating scale scores was detected between treatment groups when considering ambulatory patients only. CONCLUSIONS This study provides no data to suggest that FRDA patients could correctly determine their treatment assignment over a 2-month period. We hope that this study design will help inform future trials so that patients' experiences of symptoms are more reliably measured.
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Affiliation(s)
- Arron Cook
- Department of Molecular Neuroscience, Ataxia Centre UCL Institute of Neurology, Queen Square London UK
| | - Sylvia Boesch
- Neurologische Klinik Universitätsklinik Innsbruck Innsbruck Austria
| | - Suzette Heck
- Department of Neurology Klinikum Grosshadern Munich Germany
| | - Ewout Brunt
- Department of Neurology UMC Groningen Groningen Netherlands
| | | | - Ludger Schöls
- Department of Neurodegeneration and Hertie Institute for Clinical Brain Research University of Tübingen Tübingen Germany
- German Center for Neurodegenerative Diseases (DZNE) Tübingen Germany
| | - Angela Schulz
- Specialty Clinic for Degenerative Brain Diseases, Children’s Hospital University Medical Center Hamburg‐Eppendorf Hamburg Germany
| | - Paola Giunti
- Department of Molecular Neuroscience, Ataxia Centre UCL Institute of Neurology, Queen Square London UK
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Cotticelli MG, Xia S, Lin D, Lee T, Terrab L, Wipf P, Huryn DM, Wilson RB. Ferroptosis as a Novel Therapeutic Target for Friedreich's Ataxia. J Pharmacol Exp Ther 2019; 369:47-54. [PMID: 30635474 DOI: 10.1124/jpet.118.252759] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 01/04/2019] [Indexed: 12/17/2023] Open
Abstract
Friedreich ataxia (FRDA) is a progressive neuro- and cardio-degenerative disorder characterized by ataxia, sensory loss, and hypertrophic cardiomyopathy. In most cases, the disorder is caused by GAA repeat expansions in the first introns of both alleles of the FXN gene, resulting in decreased expression of the encoded protein, frataxin. Frataxin localizes to the mitochondrial matrix and is required for iron-sulfur-cluster biosynthesis. Decreased expression of frataxin is associated with mitochondrial dysfunction, mitochondrial iron accumulation, and increased oxidative stress. Ferropotosis is a recently identified pathway of regulated, iron-dependent cell death, which is biochemically distinct from apoptosis. We evaluated whether there is evidence for ferroptotic pathway activation in cellular models of FRDA. We found that primary patient-derived fibroblasts, murine fibroblasts with FRDA-associated mutations, and murine fibroblasts in which a repeat expansion had been introduced (knockin/knockout) were more sensitive than normal control cells to erastin, a known ferroptosis inducer. We also found that the ferroptosis inhibitors ethyl 3-(benzylamino)-4-(cyclohexylamino)benzoate (SRS11-92) and ethyl 3-amino-4-(cyclohexylamino)benzoate, used at 500 nM, were efficacious in protecting human and mouse cellular models of FRDA treated with ferric ammonium citrate (FAC) and an inhibitor of glutathione synthesis [L-buthionine (S,R)-sulfoximine (BSO)], whereas caspase-3 inhibitors failed to show significant biologic activity. Cells treated with FAC and BSO consistently showed decreased glutathione-dependent peroxidase activity and increased lipid peroxidation, both hallmarks of ferroptosis. Finally, the ferroptosis inhibitor SRS11-92 decreased the cell death associated with frataxin knockdown in healthy human fibroblasts. Taken together, these data suggest that ferroptosis inhibitors may have therapeutic potential in FRDA.
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Affiliation(s)
- M Grazia Cotticelli
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Shujuan Xia
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel Lin
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Taehee Lee
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Leila Terrab
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Peter Wipf
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Donna M Huryn
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert B Wilson
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, Pennsylvania (M.G.C., S.X., D.L., T.L., R.B.W.); Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania (L.T., P.W.); Department of Chemistry (D.M.H.), and Perelman School of Medicine (R.B.W.), University of Pennsylvania, Philadelphia, Pennsylvania
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21
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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: 43] [Impact Index Per Article: 8.6] [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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22
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Ward PGD, Harding IH, Close TG, Corben LA, Delatycki MB, Storey E, Georgiou-Karistianis N, Egan GF. Longitudinal evaluation of iron concentration and atrophy in the dentate nuclei in friedreich ataxia. Mov Disord 2019; 34:335-343. [PMID: 30624809 DOI: 10.1002/mds.27606] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/26/2018] [Accepted: 12/06/2018] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Friedreich ataxia is a recessively inherited, progressive neurological disease characterized by impaired mitochondrial iron metabolism. The dentate nuclei of the cerebellum are characteristic sites of neurodegeneration in the disease, but little is known of the longitudinal progression of abnormalities in these structures. METHODS Using in vivo magnetic resonance imaging, including quantitative susceptibility mapping, we investigated changes in iron concentration and volume in the dentate nuclei in individuals with Friedreich ataxia (n = 20) and healthy controls (n = 18) over a 2-year period. RESULTS The longitudinal rate of iron concentration was significantly elevated bilaterally in participants with Friedreich ataxia relative to healthy controls. Atrophy rates did not differ significantly between groups. Change in iron concentration and atrophy both correlated with baseline disease severity or duration, indicating sensitivity of these measures to disease stage. Specifically, atrophy was maximal in individuals early in the disease course, whereas the rate of iron concentration increased with disease progression. CONCLUSIONS Progressive dentate nucleus abnormalities are evident in vivo in Friedreich ataxia, and the rates of change of iron concentration and atrophy in these structures are sensitive to the disease stage. The findings are consistent with an increased rate of iron concentration and atrophy early in the disease, followed by iron accumulation and stable volume in later stages. This pattern suggests that iron dysregulation persists after loss of the vulnerable neurons in the dentate. The significant changes observed over a 2-year period highlight the utility of quantitative susceptibility mapping as a longitudinal biomarker and staging tool. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Phillip G D Ward
- Monash Biomedical Imaging, Monash University, Melbourne, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne, Australia
| | - Ian H Harding
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia
| | - Thomas G Close
- Monash Biomedical Imaging, Monash University, Melbourne, Australia
| | - Louise A Corben
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia.,Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia
| | - Martin B Delatycki
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia.,Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia.,Victorian Clinical Genetics Service, Parkville, Australia
| | - Elsdon Storey
- Department of Medicine, Monash University, Melbourne, Australia
| | - Nellie Georgiou-Karistianis
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia
| | - Gary F Egan
- Monash Biomedical Imaging, Monash University, Melbourne, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Melbourne, Australia
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23
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Khdour OM, Bandyopadhyay I, Visavadiya NP, Roy Chowdhury S, Hecht SM. Phenothiazine antioxidants increase mitochondrial biogenesis and frataxin levels in Friedreich's ataxia cells. MEDCHEMCOMM 2018; 9:1491-1501. [PMID: 30288223 DOI: 10.1039/c8md00274f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/25/2018] [Indexed: 12/13/2022]
Abstract
Friedreich's ataxia (FRDA) is a progressive neurodegenerative disease that is linked to transcriptional repression of the nuclear FXN gene encoding the essential mitochondrial protein frataxin (FXN). Compounds that increase frataxin levels may enable effective therapeutic intervention for blunting disease progression. Recently, we showed that lipophilic methylene violet (MV) and methylene blue (MB) analogues both conferred benefit to cultured FRDA cells in several regards, including ROS suppression, maintenance of mitochondrial membrane potential and increased ATP production. Some of the MB analogues were also shown to promote increased frataxin levels and mitochondrial biogenesis. Presently, we report that two of the MV analogues studied previously (1 and 2) also increased frataxin levels and mitochondrial biogenesis significantly. Because the substitution pattern in the two series of compounds was not the same, we also prepared new MV derivatives having the same substitution pattern as the original MB derivatives studied to enable a more direct comparison. Two of the new MV compounds, 4b and 6b, exhibited enhanced antioxidant capability, increased frataxin levels and mitochondrial biogenesis, and improved aconitase activity. These encouraging findings demonstrated that the MV analogues had better overall activity with less cytotoxicity.
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Affiliation(s)
- Omar M Khdour
- Biodesign Center for BioEnergetics , Arizona State University , Tempe , AZ 85287 , USA .
| | - Indrajit Bandyopadhyay
- Biodesign Center for BioEnergetics , Arizona State University , Tempe , AZ 85287 , USA . .,School of Molecular Sciences , Arizona State University , Tempe , AZ 85287 , USA
| | - Nishant P Visavadiya
- Biodesign Center for BioEnergetics , Arizona State University , Tempe , AZ 85287 , USA .
| | - Sandipan Roy Chowdhury
- Biodesign Center for BioEnergetics , Arizona State University , Tempe , AZ 85287 , USA . .,School of Molecular Sciences , Arizona State University , Tempe , AZ 85287 , USA
| | - Sidney M Hecht
- Biodesign Center for BioEnergetics , Arizona State University , Tempe , AZ 85287 , USA . .,School of Molecular Sciences , Arizona State University , Tempe , AZ 85287 , USA
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24
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Khdour OM, Bandyopadhyay I, Chowdhury SR, Visavadiya NP, Hecht SM. Lipophilic methylene blue analogues enhance mitochondrial function and increase frataxin levels in a cellular model of Friedreich's ataxia. Bioorg Med Chem 2018; 26:3359-3369. [PMID: 29773347 DOI: 10.1016/j.bmc.2018.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 04/25/2018] [Accepted: 05/03/2018] [Indexed: 01/31/2023]
Abstract
Friedreich's ataxia (FRDA) is an autosomal recessive neurodegenerative disorder resulting from reduced expression of the protein frataxin (FXN). Although its function is not fully understood, frataxin appears to help assemble iron sulfur clusters; these are critical for the function of many proteins, including those needed for mitochondrial energy production. Finding ways to increase FXN levels has been a major therapeutic strategy for this disease. Previously, we described a novel series of methylene violet analogues and their structural optimization as potential therapeutic agents for neurodegenerative and mitochondrial disorders. Presently, a series of methylene blue analogues has been synthesized and characterized for their in vitro biochemical and biological properties in cultured Friedreich's ataxia lymphocytes. Favorable methylene blue analogues were shown to increase frataxin levels and mitochondrial biogenesis, and to improve aconitase activity. The analogues were found to be good ROS scavengers, and able to protect cultured FRDA lymphocytes from oxidative stress resulting from inhibition of complex I and from glutathione depletion. The analogues also preserved mitochondrial membrane potential and augmented ATP production. Our results suggest that analogue 5, emerging from the initial structure of the parent compound methylene blue (MB), represents a promising lead structure and lacks the cytotoxicity associated with the parent compound MB.
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Affiliation(s)
- Omar M Khdour
- Biodesign Center for BioEnergetics, and School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA.
| | - Indrajit Bandyopadhyay
- Biodesign Center for BioEnergetics, and School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Sandipan Roy Chowdhury
- Biodesign Center for BioEnergetics, and School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Nishant P Visavadiya
- Biodesign Center for BioEnergetics, and School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Sidney M Hecht
- Biodesign Center for BioEnergetics, and School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
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25
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Cotticelli MG, Xia S, Kaur A, Lin D, Wang Y, Ruff E, Tobias JW, Wilson RB. Identification of p38 MAPK as a novel therapeutic target for Friedreich's ataxia. Sci Rep 2018; 8:5007. [PMID: 29568068 PMCID: PMC5864720 DOI: 10.1038/s41598-018-23168-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 03/07/2018] [Indexed: 01/28/2023] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive neuro- and cardio-degenerative disorder caused by decreased expression of frataxin, a protein that localizes to mitochondria and is critical for iron-sulfur-cluster (ISC) assembly. There are no proven effective treatments for FRDA. We previously screened a random shRNA library and identified a synthetic shRNA (gFA11) that reverses the growth defect of FRDA cells in culture. We now report that gFA11 decreases cytokine secretion in primary FRDA fibroblasts and reverts other changes associated with cell senescence. The gene-expression profile induced by gFA11 is remarkably similar to the gene-expression profile induced by the p38 MAPK inhibitor SB203580. We found that p38 phosphorylation, indicating activation of the p38 pathway, is higher in FRDA cells than in normal control cells, and that siRNA knockdown of frataxin in normal fibroblasts also increases p38 phosphorylation. Treatment of FRDA cells with p38 inhibitors recapitulates the reversal of the slow-growth phenotype induced by clone gFA11. These data highlight the involvement of the p38 MAPK pathway in the pathogenesis of FRDA and the potential use of p38 inhibitors as a treatment for FRDA.
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Affiliation(s)
- M Grazia Cotticelli
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, PA, USA
- The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, USA
| | - Shujuan Xia
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, PA, USA
- The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, USA
| | - Avinash Kaur
- Marian University College of Osteopathic Medicine, Indianapolis, USA
| | - Daniel Lin
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, PA, USA
- The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, USA
| | - Yongping Wang
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, PA, USA
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA
| | - Eric Ruff
- State University of New York Downstate College of Medicine, New York, USA
| | - John W Tobias
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA
| | - Robert B Wilson
- Department of Pathology and Laboratory Medicine, Children's Hospital Philadelphia, Philadelphia, PA, USA.
- The Penn Medicine/CHOP Center of Excellence for Friedreich's Ataxia Research, Philadelphia, USA.
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, USA.
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26
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Progress in the treatment of Friedreich ataxia. Neurol Neurochir Pol 2018; 52:129-139. [PMID: 29499876 DOI: 10.1016/j.pjnns.2018.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 02/12/2018] [Indexed: 11/19/2022]
Abstract
Friedreich ataxia (FRDA) is a progressive neurological disorder affecting approximately 1 in 29,000 individuals of European descent. At present, there is no approved pharmacological treatment for this condition however research into treatment of FRDA has advanced considerably over the last two decades since the genetic cause was identified. Current proposed treatment strategies include decreasing oxidative stress, increasing cellular frataxin, improving mitochondrial function as well as modulating frataxin controlled metabolic pathways. Genetic and cell based therapies also hold great promise. Finally, physical therapies are being explored as a means of maximising function in those affected by FRDA.
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27
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Chandran V, Gao K, Swarup V, Versano R, Dong H, Jordan MC, Geschwind DH. Inducible and reversible phenotypes in a novel mouse model of Friedreich's Ataxia. eLife 2017; 6:e30054. [PMID: 29257745 PMCID: PMC5736353 DOI: 10.7554/elife.30054] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Abstract
Friedreich's ataxia (FRDA), the most common inherited ataxia, is caused by recessive mutations that reduce the levels of frataxin (FXN), a mitochondrial iron binding protein. We developed an inducible mouse model of Fxn deficiency that enabled us to control the onset and progression of disease phenotypes by the modulation of Fxn levels. Systemic knockdown of Fxn in adult mice led to multiple phenotypes paralleling those observed in human patients across multiple organ systems. By reversing knockdown after clinical features appear, we were able to determine to what extent observed phenotypes represent reversible cellular dysfunction. Remarkably, upon restoration of near wild-type FXN levels, we observed significant recovery of function, associated pathology and transcriptomic dysregulation even after substantial motor dysfunction and pathology were observed. This model will be of broad utility in therapeutic development and in refining our understanding of the relative contribution of reversible cellular dysfunction at different stages in disease.
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Affiliation(s)
- Vijayendran Chandran
- Program in Neurogenetics, Department of Neurology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
| | - Kun Gao
- Program in Neurogenetics, Department of Neurology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
| | - Vivek Swarup
- Program in Neurogenetics, Department of Neurology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
| | - Revital Versano
- Program in Neurogenetics, Department of Neurology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
| | - Hongmei Dong
- Program in Neurogenetics, Department of Neurology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
| | - Maria C Jordan
- Department of Physiology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
| | - Daniel H Geschwind
- Program in Neurogenetics, Department of Neurology, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
- Department of Human Genetics, David Geffen School of MedicineUniversity of California, Los AngelesLos AngelesUnited States
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28
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Marcus D, Lichtenstein M, Cohen N, Hadad R, Erlich-Hadad T, Greif H, Lorberboum-Galski H. Heterologous mitochondrial targeting sequences can deliver functional proteins into mitochondria. Int J Biochem Cell Biol 2016; 81:48-56. [PMID: 27771440 DOI: 10.1016/j.biocel.2016.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 10/13/2016] [Accepted: 10/18/2016] [Indexed: 01/23/2023]
Abstract
Mitochondrial Targeting Sequences (MTSs) are responsible for trafficking nuclear-encoded proteins into mitochondria. Once entering the mitochondria, the MTS is recognized and cleaved off. Some MTSs are long and undergo two-step processing, as in the case of the human frataxin (FXN) protein (80aa), implicated in Friedreich's ataxia (FA). Therefore, we chose the FXN protein to examine whether nuclear-encoded mitochondrial proteins can efficiently be targeted via a heterologous MTS (hMTS) and deliver a functional protein into mitochondria. We examined three hMTSs; that of citrate synthase (cs), lipoamide deydrogenase (LAD) and C6ORF66 (ORF), as classically MTS sequences, known to be removed by one-step processing, to deliver FXN into mitochondria, in the form of fusion proteins. We demonstrate that using hMTSs for delivering FXN results in the production of 4-5-fold larger amounts of the fusion proteins, and at 4-5-fold higher concentrations. Moreover, hMTSs delivered a functional FXN protein into the mitochondria even more efficiently than the native MTSfxn, as evidenced by the rescue of FA patients' cells from oxidative stress; demonstrating a 18%-54% increase in cell survival; and a 13%-33% increase in ATP levels, as compared to the fusion protein carrying the native MTS. One fusion protein with MTScs increased aconitase activity within patients' cells, by 400-fold. The implications form our studies are of vast importance for both basic and translational research of mitochondrial proteins as any mitochondrial protein can be delivered efficiently by an hMTS. Moreover, effective targeting of functional proteins is important for restoration of mitochondrial function and treatment of related disorders.
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Affiliation(s)
- Dana Marcus
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Michal Lichtenstein
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Natali Cohen
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Rita Hadad
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Tal Erlich-Hadad
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | | | - Haya Lorberboum-Galski
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada (IMRIC), Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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29
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Vitamin K2 suppresses rotenone-induced microglial activation in vitro. Acta Pharmacol Sin 2016; 37:1178-89. [PMID: 27498777 DOI: 10.1038/aps.2016.68] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/30/2016] [Indexed: 02/06/2023] Open
Abstract
AIM Increasing evidence has shown that environmental factors such as rotenone and paraquat induce neuroinflammation, which contributes to the pathogenesis of Parkinson's disease (PD). In this study, we investigated the molecular mechanisms underlying the repression by menaquinone-4 (MK-4), a subtype of vitamin K2, of rotenone-induced microglial activation in vitro. METHODS A microglial cell line (BV2) was exposed to rotenone (1 μmol/L) with or without MK-4 treatment. The levels of TNF-α or IL-1β in 100 μL of cultured media of BV2 cells were measured using ELISA kits. BV2 cells treated with rotenone with or without MK4 were subjected to mitochondrial membrane potential, ROS production, immunofluorescence or immunoblot assays. The neuroblastoma SH-SY5Y cells were treated with conditioned media (CM) of BV2 cells that were exposed to rotenone with or without MK-4 treatment, and the cell viability was assessed using MTT assay. RESULTS In rotenone-treated BV2 cells, MK-4 (0.5-20 μmol/L) dose-dependently suppressed the upregulation in the expression of iNOS and COX-2 in the cells, as well as the production of TNF-α and IL-1β in the cultured media. MK-4 (5-20 μmol/L) significantly inhibited rotenone-induced nuclear translocation of NF-κB in BV2 cells. MK-4 (5-20 μmol/L) significantly inhibited rotenone-induced p38 activation, ROS production, and caspase-1 activation in BV2 cells. MK-4 (5-20 μmol/L) also restored the mitochondrial membrane potential that had been damaged by rotenone. Exposure to CM from rotenone-treated BV2 cells markedly decreased the viability of SH-SY5Y cells. However, this rotenone-activated microglia-mediated death of SH-SY5Y cells was significantly attenuated when the BV2 cells were co-treated with MK-4 (5-20 μmol/L). CONCLUSION Vitamin K2 can directly suppress rotenone-induced activation of microglial BV2 cells in vitro by repressing ROS production and p38 activation.
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30
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Chiang S, Kovacevic Z, Sahni S, Lane DJR, Merlot AM, Kalinowski DS, Huang MLH, Richardson DR. Frataxin and the molecular mechanism of mitochondrial iron-loading in Friedreich's ataxia. Clin Sci (Lond) 2016; 130:853-70. [PMID: 27129098 DOI: 10.1042/cs20160072] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/16/2016] [Indexed: 12/19/2022]
Abstract
The mitochondrion is a major site for the metabolism of the transition metal, iron, which is necessary for metabolic processes critical for cell vitality. The enigmatic mitochondrial protein, frataxin, is known to play a significant role in both cellular and mitochondrial iron metabolism due to its iron-binding properties and its involvement in iron-sulfur cluster (ISC) and heme synthesis. The inherited neuro- and cardio-degenerative disease, Friedreich's ataxia (FA), is caused by the deficient expression of frataxin that leads to deleterious alterations in iron metabolism. These changes lead to the accumulation of inorganic iron aggregates in the mitochondrial matrix that are presumed to play a key role in the oxidative damage and subsequent degenerative features of this disease. Furthermore, the concurrent dys-regulation of cellular antioxidant defense, which coincides with frataxin deficiency, exacerbates oxidative stress. Hence, the pathogenesis of FA underscores the importance of the integrated homeostasis of cellular iron metabolism and the cytoplasmic and mitochondrial redox environments. This review focuses on describing the pathogenesis of the disease, the molecular mechanisms involved in mitochondrial iron-loading and the dys-regulation of cellular antioxidant defense due to frataxin deficiency. In turn, current and emerging therapeutic strategies are also discussed.
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Affiliation(s)
- Shannon Chiang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Zaklina Kovacevic
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Sumit Sahni
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Angelica M Merlot
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Danuta S Kalinowski
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael L-H Huang
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia )
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology, University of Sydney, Sydney, New South Wales 2006, Australia )
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31
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Compartmentalization of iron between mitochondria and the cytosol and its regulation. Eur J Cell Biol 2015; 94:292-308. [DOI: 10.1016/j.ejcb.2015.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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32
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Filali M, Lalonde R, Gérard C, Coulombe Z, Tremblay JP. Sensorimotor skills in Fxn KO/Mck mutants deficient for frataxin in muscle. Brain Res 2015; 1608:91-6. [PMID: 25765157 DOI: 10.1016/j.brainres.2015.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/17/2015] [Accepted: 03/01/2015] [Indexed: 10/23/2022]
Abstract
Friedreich ataxia is the most common autosomal recessive disorder of the cerebellum, causing degeneration of spinal sensory neurons and spinocerebellar tracts. The disease is caused by severely reduced levels of frataxin, a mitochondrial protein involved in iron metabolism. An experimental model has been generated by crossing mice homozygous for a conditional allele of the Fxn gene with mice heterozygous for a deleted exon 4 of Fxn carrying a tissue-specific Cre transgene under control of the muscle creatine kinase promoter. Relative to wild-type, Fxn null mutants were impaired on tests of motor coordination comprising horizontal bar, vertical pole, and the rotorod as well as displaying gait anomalies and the hindlimb clasping response. The Fxn KO/Mck model reproduces some key features of patients with Friedreich ataxia and provides an opportunity of ameliorating their symptoms with experimental therapies.
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Affiliation(s)
- Mohammed Filali
- Plateforme d׳analyse fonctionnelle du comportement animal, Axe Neurosciences, Centre Hospitalier Universitaire de Québec, Département de Médecine Moléculaire, Faculté de Médecine Université Laval, Canada.
| | - Robert Lalonde
- Université de Rouen, Faculté de Sciences and Département de Psychologie, Laboratoire ICONES EA 4699, 76821 Mont-Saint-Aignan, France
| | - Catherine Gérard
- Plateforme d׳analyse fonctionnelle du comportement animal, Axe Neurosciences, Centre Hospitalier Universitaire de Québec, Département de Médecine Moléculaire, Faculté de Médecine Université Laval, Canada
| | - Zoé Coulombe
- Plateforme d׳analyse fonctionnelle du comportement animal, Axe Neurosciences, Centre Hospitalier Universitaire de Québec, Département de Médecine Moléculaire, Faculté de Médecine Université Laval, Canada
| | - Jacques P Tremblay
- Plateforme d׳analyse fonctionnelle du comportement animal, Axe Neurosciences, Centre Hospitalier Universitaire de Québec, Département de Médecine Moléculaire, Faculté de Médecine Université Laval, Canada
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33
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Mena NP, Urrutia PJ, Lourido F, Carrasco CM, Núñez MT. Mitochondrial iron homeostasis and its dysfunctions in neurodegenerative disorders. Mitochondrion 2015; 21:92-105. [PMID: 25667951 DOI: 10.1016/j.mito.2015.02.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/13/2015] [Accepted: 02/02/2015] [Indexed: 12/17/2022]
Abstract
Synthesis of the iron-containing prosthetic groups-heme and iron-sulfur clusters-occurs in mitochondria. The mitochondrion is also an important producer of reactive oxygen species (ROS), which are derived from electrons leaking from the electron transport chain. The coexistence of both ROS and iron in the secluded space of the mitochondrion makes this organelle particularly prone to oxidative damage. Here, we review the elements that configure mitochondrial iron homeostasis and discuss the principles of iron-mediated ROS generation in mitochondria. We also review the evidence for mitochondrial dysfunction and iron accumulation in Alzheimer's disease, Huntington Disease, Friedreich's ataxia, and in particular Parkinson's disease. We postulate that a positive feedback loop of mitochondrial dysfunction, iron accumulation, and ROS production accounts for the process of cell death in various neurodegenerative diseases in which these features are present.
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Affiliation(s)
- Natalia P Mena
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Pamela J Urrutia
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Fernanda Lourido
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Carlos M Carrasco
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile
| | - Marco T Núñez
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile; Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile, Santiago, Chile.
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Zwarts L, Van Eijs F, Callaerts P. Glia in Drosophila behavior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 201:879-93. [PMID: 25336160 DOI: 10.1007/s00359-014-0952-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 10/02/2014] [Accepted: 10/07/2014] [Indexed: 02/06/2023]
Abstract
Glial cells constitute about 10 % of the Drosophila nervous system. The development of genetic and molecular tools has helped greatly in defining different types of glia. Furthermore, considerable progress has been made in unraveling the mechanisms that control the development and differentiation of Drosophila glia. By contrast, the role of glia in adult Drosophila behavior is not well understood. We here summarize recent work describing the role of glia in normal behavior and in Drosophila models for neurological and behavioral disorders.
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Affiliation(s)
- L Zwarts
- Laboratory of Behavioral and Developmental Genetics VIB Center for the Biology of Disease, Center for Human Genetics, KULeuven, O&N IV Herestraat 49, Box 602, 3000, Louvain, Belgium
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Wang Y, Wang Y, Marcus S, Busenlehner LS. The role of frataxin in fission yeast iron metabolism: implications for Friedreich's ataxia. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1840:3022-33. [PMID: 24997422 DOI: 10.1016/j.bbagen.2014.06.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/25/2014] [Accepted: 06/26/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND The neurodegenerative disease Friedreich's ataxia is the result of frataxin deficiency. Frataxin is a mitochondrial protein involved in iron-sulfur cluster (Fe-S) cofactor biogenesis, but its functional role in this pathway is debated. This is due to the interconnectivity of iron metabolic and oxidative stress response pathways that make distinguishing primary effects of frataxin deficiency challenging. Since Fe-S cluster assembly is conserved, frataxin overexpression phenotypes in a simple eukaryotic organism will provide additional insight into frataxin function. METHODS The Schizosaccharomyces pombe frataxin homologue (fxn1) was overexpressed from a plasmid under a thiamine repressible promoter. The S. pombe transformants were characterized at several expression strengths for cellular growth, mitochondrial organization, iron levels, oxidative stress, and activities of Fe-S cluster containing enzymes. RESULTS Observed phenotypes were dependent on the amount of Fxn1 overexpression. High Fxn1 overexpression severely inhibited S. pombe growth, impaired mitochondrial membrane integrity and cellular respiration, and led to Fxn1 aggregation. Cellular iron accumulation was observed at moderate Fxn1 overexpression but was most pronounced at high levels of Fxn1. All levels of Fxn1 overexpression up-regulated oxidative stress defense and mitochondrial Fe-S cluster containing enzyme activities. CONCLUSIONS Despite the presence of oxidative stress and accumulated iron, activation of Fe-S cluster enzymes was common to all levels of Fxn1 overexpression; therefore, Fxn1 may regulate the efficiency of Fe-S cluster biogenesis in S. pombe. GENERAL SIGNIFICANCE We provide evidence that suggests that dysregulated Fe-S cluster biogenesis is a primary effect of both frataxin overexpression and deficiency as in Friedreich's ataxia.
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Affiliation(s)
- Yu Wang
- Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Yiwei Wang
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - S Marcus
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | - L S Busenlehner
- Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487, USA.
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Solbach K, Kraff O, Minnerop M, Beck A, Schöls L, Gizewski E, Ladd M, Timmann D. Cerebellar pathology in Friedreich's ataxia: atrophied dentate nuclei with normal iron content. Neuroimage Clin 2014; 6:93-9. [PMID: 25379420 PMCID: PMC4215469 DOI: 10.1016/j.nicl.2014.08.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 08/06/2014] [Accepted: 08/21/2014] [Indexed: 01/03/2023]
Abstract
BACKGROUND In Friedreich's ataxia (FA) the genetically decreased expression of the mitochondrial protein frataxin leads to disturbance of the mitochondrial iron metabolism. Within the cerebellum the dentate nuclei (DN) are primarily affected. Histopathological studies show atrophy and accumulation of mitochondrial iron in DN. Dentate iron content has been suggested as a biomarker to measure the effects of siderophores/antioxidant treatment of FA. We assessed the iron content and the volume of DN in FA patients and controls based on ultra-high-field MRI (7 Tesla) images. METHODS Fourteen FA patients (mean age 38.1 yrs) and 14 age- and gender-matched controls participated. Multi-echo gradient echo and susceptibility weighted imaging (SWI) sequences were acquired on a 7 T whole-body scanner. For comparison SWI images were acquired on a 1.5 T MR scanner. Volumes of the DN and cerebellum were assessed at 7 and 1.5 T, respectively. Parametric maps of T2 and T2* sequences were created and proton transverse relaxation rates were estimated as a measure of iron content. RESULTS In FA, the DN and the cerebellum were significantly smaller compared to controls. However, proton transverse relaxation rates of the DN were not significantly different between both groups. CONCLUSIONS Applying in vivo MRI methods we could demonstrate significant atrophy of the DN in the presence of normal iron content. The findings suggest that relaxation rates are not reliable biomarkers in clinical trials evaluating the potential effect of FA therapy.
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Affiliation(s)
- K. Solbach
- Department of Neurology, University of Duisburg-Essen, Hufelandstr. 55, Essen 45147, Germany
| | - O. Kraff
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Arendahls Wiese 199, Essen 45141, Germany
| | - M. Minnerop
- Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich 52425, Germany
- Department of Neurology, University Hospital Bonn, Sigmund-Freud-straße 25, Bonn 53127, Germany
| | - A. Beck
- Department of Computer Sciences, University of Düsseldorf, Universitätsstraße 1, Düsseldorf 40225, Germany
| | - L. Schöls
- Department of Neurology, Eberhard Karls-University, Geschwister-Scholl-platz, Tübingen, Tübingen 72074, Germany
- Hertie Institute for Clinical Brain Research, Eberhard Karls-University Tübingen, Hoppe-Seyler-straße 3, Tübingen 72076, Germany
- German Research Center for Neurodegenerative Diseases (DZNE), Otfried-Müller-straße 27, Tübingen 72076, Germany
| | - E.R. Gizewski
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University of Duisburg-Essen, Hufelandstr. 55, Essen 45147, Germany
| | - M.E. Ladd
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Arendahls Wiese 199, Essen 45141, Germany
- Institute of Diagnostic and Interventional Radiology and Neuroradiology, University of Duisburg-Essen, Hufelandstr. 55, Essen 45147, Germany
| | - D. Timmann
- Department of Neurology, University of Duisburg-Essen, Hufelandstr. 55, Essen 45147, Germany
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Delatycki MB, Tai G, Corben L, Yiu EM, Evans-Galea MV, Stephenson SEM, Gurrin L, Allen KJ, Lynch D, Lockhart PJ. HFE p.C282Y heterozygosity is associated with earlier disease onset in Friedreich ataxia. Mov Disord 2014; 29:940-3. [PMID: 24390816 DOI: 10.1002/mds.25795] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 11/26/2013] [Accepted: 12/03/2013] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Friedreich ataxia (FRDA) generally results from reduced frataxin, a mitochondrial protein involved in iron metabolism. We assessed whether HFE p.C282Y and/or p.H63D heterozygosity modifies age at disease onset or disease severity in individuals with FRDA. METHODS One hundred seventy individuals with FRDA were assessed for the association of HFE p.C282Y and p.H63D with (1) age at disease onset and (2) Friedreich Ataxia Rating Scale (FARS) score. RESULTS After adjusting for the smaller FXN GAA repeat size and sex, individuals with FRDA and heterozygous for p.C282Y had disease onset on average 3.72 years earlier than those homozygous for the wild-type amino acid (P = 0.02). Neither mutation affected disease severity as measured by FARS. CONCLUSIONS It is hypothesized that the association between p.C282Y heterozygosity and an earlier age at FRDA onset relates to exacerbation of the already dysregulated iron metabolism that plays a major role in the pathogenesis of FRDA.
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Affiliation(s)
- Martin B Delatycki
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia; Clinical Genetics, Austin Health, Heidelberg, Victoria, Australia; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia; School of Psychology and Psychiatry, Monash University, Clayton, Victoria, Australia
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Dhamija R, Kirmani S. A 7-year-old girl with hypertrophic cardiomyopathy and progressive scoliosis. Semin Pediatr Neurol 2014; 21:67-71. [PMID: 25149925 DOI: 10.1016/j.spen.2014.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report a 7 year old girl who was evaluated for progressive thoracolumbar scoliosis and hypertrophic cardiomyopathy. Neurological examination was found to be abnormal and significant for absent reflexes and weakness distally in lower extremities and positive Romberg sign. Electromyogram showed length-dependent, axonal, sensorimotor polyneuropathy. Frataxin levels were low at 3ng/mL. Molecular testing for Friedreich ataxia showed significantly expanded GAA repeats at 799 (abnormal >67 GAA repeats) on one allele and a heterozygous disease causing mutation, c.317T>C (p.Leu106Ser) on the other allele, confirming the diagnosis. A review of Friedreich ataxia is provided in the case report.
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Affiliation(s)
| | - Salman Kirmani
- Department of Medical Genetics, Mayo Clinic, Rochester, MN
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39
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Sarsero JP, Holloway TP, Li L, Finkelstein DI, Ioannou PA. Rescue of the Friedreich ataxia knockout mutation in transgenic mice containing an FXN-EGFP genomic reporter. PLoS One 2014; 9:e93307. [PMID: 24667739 PMCID: PMC3965543 DOI: 10.1371/journal.pone.0093307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 03/03/2014] [Indexed: 11/18/2022] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive disorder characterized by neurodegeneration and cardiomyopathy. The presence of a GAA trinucleotide repeat expansion in the first intron of the FXN gene results in the inhibition of gene expression and an insufficiency of the mitochondrial protein frataxin. We previously generated BAC-based transgenic mice containing an FXN-EGFP genomic reporter construct in which the EGFP gene is fused in-frame immediately following the final codon of exon 5a of the human FXN gene. These transgenic mice were mated with mice heterozygous for a knockout mutation of the murine Fxn gene, to generate mice homozygous for the Fxn knockout mutation and hemizygous or homozygous for the human transgene. Rescue of the embryonic lethality that is associated with homozygosity for the Fxn knockout mutation was observed. Rescue mice displayed normal behavioral and histological parameters with normal viability, fertility and life span and without any signs of aberrant phenotype. Immunoblotting demonstrated the production of full-length frataxin-EGFP fusion protein that appears to act as a bifunctional hybrid protein. This study shows frataxin replacement may be a viable therapeutic option. Further, these mice should provide a useful resource for the study of human FXN gene expression, frataxin function, the evaluation of pharmacologic inducers of FXN expression in a whole-animal model and provide a useful source of cells for stem cell transplantation studies.
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Affiliation(s)
- Joseph P. Sarsero
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Timothy P. Holloway
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Lingli Li
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - David I. Finkelstein
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
| | - Panos A. Ioannou
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, Victoria, Australia
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Saha PP, Kumar SKP, Srivastava S, Sinha D, Pareek G, D'Silva P. The presence of multiple cellular defects associated with a novel G50E iron-sulfur cluster scaffold protein (ISCU) mutation leads to development of mitochondrial myopathy. J Biol Chem 2014; 289:10359-10377. [PMID: 24573684 DOI: 10.1074/jbc.m113.526665] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are versatile cofactors involved in regulating multiple physiological activities, including energy generation through cellular respiration. Initially, the Fe-S clusters are assembled on a conserved scaffold protein, iron-sulfur cluster scaffold protein (ISCU), in coordination with iron and sulfur donor proteins in human mitochondria. Loss of ISCU function leads to myopathy, characterized by muscle wasting and cardiac hypertrophy. In addition to the homozygous ISCU mutation (g.7044G→C), compound heterozygous patients with severe myopathy have been identified to carry the c.149G→A missense mutation converting the glycine 50 residue to glutamate. However, the physiological defects and molecular mechanism associated with G50E mutation have not been elucidated. In this report, we uncover mechanistic insights concerning how the G50E ISCU mutation in humans leads to the development of severe ISCU myopathy, using a human cell line and yeast as the model systems. The biochemical results highlight that the G50E mutation results in compromised interaction with the sulfur donor NFS1 and the J-protein HSCB, thus impairing the rate of Fe-S cluster synthesis. As a result, electron transport chain complexes show significant reduction in their redox properties, leading to loss of cellular respiration. Furthermore, the G50E mutant mitochondria display enhancement in iron level and reactive oxygen species, thereby causing oxidative stress leading to impairment in the mitochondrial functions. Thus, our findings provide compelling evidence that the respiration defect due to impaired biogenesis of Fe-S clusters in myopathy patients leads to manifestation of complex clinical symptoms.
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Affiliation(s)
- Prasenjit Prasad Saha
- Department of Biochemistry, Indian Institute of Science, Biological Sciences Building, Bangalore 560012, Karnataka, India
| | - S K Praveen Kumar
- Department of Biochemistry, Indian Institute of Science, Biological Sciences Building, Bangalore 560012, Karnataka, India
| | - Shubhi Srivastava
- Department of Biochemistry, Indian Institute of Science, Biological Sciences Building, Bangalore 560012, Karnataka, India
| | - Devanjan Sinha
- Department of Biochemistry, Indian Institute of Science, Biological Sciences Building, Bangalore 560012, Karnataka, India
| | - Gautam Pareek
- Department of Biochemistry, Indian Institute of Science, Biological Sciences Building, Bangalore 560012, Karnataka, India
| | - Patrick D'Silva
- Department of Biochemistry, Indian Institute of Science, Biological Sciences Building, Bangalore 560012, Karnataka, India.
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41
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Stehling O, Wilbrecht C, Lill R. Mitochondrial iron-sulfur protein biogenesis and human disease. Biochimie 2014; 100:61-77. [PMID: 24462711 DOI: 10.1016/j.biochi.2014.01.010] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/13/2014] [Indexed: 12/29/2022]
Abstract
Work during the past 14 years has shown that mitochondria are the primary site for the biosynthesis of iron-sulfur (Fe/S) clusters. In fact, it is this process that renders mitochondria essential for viability of virtually all eukaryotes, because they participate in the synthesis of the Fe/S clusters of key nuclear and cytosolic proteins such as DNA polymerases, DNA helicases, and ABCE1 (Rli1), an ATPase involved in protein synthesis. As a consequence, mitochondrial function is crucial for nuclear DNA synthesis and repair, ribosomal protein synthesis, and numerous other extra-mitochondrial pathways including nucleotide metabolism and cellular iron regulation. Within mitochondria, the synthesis of Fe/S clusters and their insertion into apoproteins is assisted by 17 proteins forming the ISC (iron-sulfur cluster) assembly machinery. Biogenesis of mitochondrial Fe/S proteins can be dissected into three main steps: First, a Fe/S cluster is generated de novo on a scaffold protein. Second, the Fe/S cluster is dislocated from the scaffold and transiently bound to transfer proteins. Third, the latter components, together with specific ISC targeting factors insert the Fe/S cluster into client apoproteins. Disturbances of the first two steps impair the maturation of extra-mitochondrial Fe/S proteins and affect cellular and systemic iron homeostasis. In line with the essential function of mitochondria, genetic mutations in a number of ISC genes lead to severe neurological, hematological and metabolic diseases, often with a fatal outcome in early childhood. In this review we briefly summarize our current functional knowledge on the ISC assembly machinery, and we present a comprehensive overview of the various Fe/S protein assembly diseases.
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Affiliation(s)
- Oliver Stehling
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany
| | - Claudia Wilbrecht
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Robert-Koch-Str. 6, 35032 Marburg, Germany; Max-Planck-Institut für terrestrische Mikrobiologie, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany; LOEWE Zentrum für Synthetische Mikrobiologie SynMikro, Hans-Meerwein-Str., 35043 Marburg, Germany.
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42
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Holmes-Hampton GP, Tong WH, Rouault TA. Biochemical and biophysical methods for studying mitochondrial iron metabolism. Methods Enzymol 2014; 547:275-307. [PMID: 25416363 DOI: 10.1016/b978-0-12-801415-8.00015-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Iron is a heavily utilized element in organisms and numerous mechanisms accordingly regulate the trafficking, metabolism, and storage of iron. Despite the high regulation of iron homeostasis, several diseases and mutations can lead to the misregulation and often accumulation of iron in the cytosol or mitochondria of tissues. To understand the genesis of iron overload, it is necessary to employ various techniques to quantify iron in organisms and mitochondria. This chapter discusses techniques for determining the total iron content of tissue samples, ranging from colorimetric determination of iron concentrations, atomic absorption spectroscopy, inductively coupled plasma-optical emission spectroscopy, and inductively coupled plasma-mass spectrometry. In addition, we discuss in situ techniques for analyzing iron including electron microscopic nonheme iron histochemistry, electron energy loss spectroscopy, synchrotron X-ray fluorescence imaging, and confocal Raman microscopy. Finally, we discuss biophysical methods for studying iron in isolated mitochondria, including ultraviolet-visible, electron paramagnetic resonance, X-ray absorbance, and Mössbauer spectroscopies. This chapter should aid researchers to select and interpret mitochondrial iron quantifications.
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Affiliation(s)
- Gregory P Holmes-Hampton
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA
| | - Wing-Hang Tong
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA
| | - Tracey A Rouault
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA.
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Abstract
Friedreich ataxia is the most common autosomal recessive ataxia. It is a progressive neurodegenerative disorder, typically with onset before 20 years of age. Signs and symptoms include progressive ataxia, ascending weakness and ascending loss of vibration and joint position senses, pes cavus, scoliosis, cardiomyopathy, and arrhythmias. There are no disease-modifying medications to either slow or halt the progression of the disease, but research investigating therapies to increase endogenous frataxin production and decrease the downstream consequences of disrupted iron homeostasis is ongoing. Clinical trials of promising medications are underway, and the treatment era of Friedreich ataxia is beginning.
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Affiliation(s)
- Abigail Collins
- Pediatrics and Neurology, Children's Hospital Colorado, University of Colorado, Denver, School of Medicine, 13123 East 16th Avenue, B155, Aurora, CO 80045, USA.
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Parkinson MH, Schulz JB, Giunti P. Co-enzyme Q10 and idebenone use in Friedreich's ataxia. J Neurochem 2013; 126 Suppl 1:125-41. [PMID: 23859348 DOI: 10.1111/jnc.12322] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/22/2013] [Accepted: 05/22/2013] [Indexed: 12/28/2022]
Abstract
Friedreich's ataxia is a debilitating progressive neurodegenerative disease associated with cardiomyopathy and other features. The underlying cause is a deficiency of the mitochondrial protein frataxin which causes mitochondrial iron deposition, increased oxidative stress and impaired adenosine triphosphate production. Over the last 15 years, multiple clinical trials have assessed the efficacy of antioxidant agents in this disease. This article reviews trials of the two most important agents, namely co-enzyme Q10 and idebenone.
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Affiliation(s)
- Michael H Parkinson
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
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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: 88] [Impact Index Per Article: 8.0] [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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Amela I, Delicado P, Gómez A, Querol E, Cedano J. A dynamic model of the proteins that form the initial iron-sulfur cluster biogenesis machinery in yeast mitochondria. Protein J 2013; 32:183-96. [PMID: 23463383 DOI: 10.1007/s10930-013-9475-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The assembly of iron-sulfur clusters (ISCs) in eukaryotes involves the protein Frataxin. Deficits in this protein have been associated with iron inside the mitochondria and impair ISC biogenesis as it is postulated to act as the iron donor for ISCs assembly in this organelle. A pronounced lack of Frataxin causes Friedreich's Ataxia, which is a human neurodegenerative and hereditary disease mainly affecting the equilibrium, coordination, muscles and heart. Moreover, it is the most common autosomal recessive ataxia. High similarities between the human and yeast molecular mechanisms that involve Frataxin have been suggested making yeast a good model to study that process. In yeast, the protein complex that forms the central assembly platform for the initial step of ISC biogenesis is composed by yeast frataxin homolog, Nfs1-Isd11 and Isu. In general, it is commonly accepted that protein function involves interaction with other protein partners, but in this case not enough is known about the structure of the protein complex and, therefore, how it exactly functions. The objective of this work is to model the protein complex in order to gain insight into structural details that end up with its biological function. To achieve this goal several bioinformatics tools, modeling techniques and protein docking programs have been used. As a result, the structure of the protein complex and the dynamic behavior of its components, along with that of the iron and sulfur atoms required for the ISC assembly, have been modeled. This hypothesis will help to better understand the function and molecular properties of Frataxin as well as those of its ISC assembly protein partners.
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Affiliation(s)
- I Amela
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i de Biomedicina, Parc de Recerca Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Catalonia, Spain
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47
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Li L, Voullaire L, Sandi C, Pook MA, Ioannou PA, Delatycki MB, Sarsero JP. Pharmacological screening using an FXN-EGFP cellular genomic reporter assay for the therapy of Friedreich ataxia. PLoS One 2013; 8:e55940. [PMID: 23418481 PMCID: PMC3572186 DOI: 10.1371/journal.pone.0055940] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 01/03/2013] [Indexed: 11/18/2022] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive disorder characterized by neurodegeneration and cardiomyopathy. The presence of a GAA trinucleotide repeat expansion in the first intron of the FXN gene results in the inhibition of gene expression and an insufficiency of the mitochondrial protein frataxin. There is a correlation between expansion length, the amount of residual frataxin and the severity of disease. As the coding sequence is unaltered, pharmacological up-regulation of FXN expression may restore frataxin to therapeutic levels. To facilitate screening of compounds that modulate FXN expression in a physiologically relevant manner, we established a cellular genomic reporter assay consisting of a stable human cell line containing an FXN-EGFP fusion construct, in which the EGFP gene is fused in-frame with the entire normal human FXN gene present on a BAC clone. The cell line was used to establish a fluorometric cellular assay for use in high throughput screening (HTS) procedures. A small chemical library containing FDA-approved compounds and natural extracts was screened and analyzed. Compound hits identified by HTS were further evaluated by flow cytometry in the cellular genomic reporter assay. The effects on FXN mRNA and frataxin protein levels were measured in lymphoblast and fibroblast cell lines derived from individuals with FRDA and in a humanized GAA repeat expansion mouse model of FRDA. Compounds that were established to increase FXN gene expression and frataxin levels included several anti-cancer agents, the iron-chelator deferiprone and the phytoalexin resveratrol.
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Affiliation(s)
- Lingli Li
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Lucille Voullaire
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Chiranjeevi Sandi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Mark A. Pook
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Panos A. Ioannou
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Martin B. Delatycki
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Clinical Genetics, Austin Health, Heidelberg, Victoria, Australia
| | - Joseph P. Sarsero
- Cell and Gene Therapy, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, Victoria, Australia
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48
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Abstract
There are now 21 agents or classes of therapeutic agents in the Friedreich ataxia research pipeline (http://www.curefa.org/pipeline.html) that have been developed in the 15 years since the discovery of the frataxin gene, with the ongoing characterization of its mutations and the resulting molecular pathology. Twenty-four studies are currently posted on ClinicalTrials.gov. Twenty-seven works discussing the results of clinical trials in Friedreich ataxia have been published. In 2010, 42 public (National Institutes of Health) and private (Friedreich Ataxia Research Alliance, Muscular Dystrophy Association, and National Ataxia Foundation) grants were funded for translational and clinical research in Friedreich ataxia. Millions of dollars from public, private, and industry-based initiatives have been dedicated to research in Friedreich ataxia therapeutics. Despite this vigorous international effort, there is as yet no proven disease-modifying therapy for Friedreich ataxia.
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Affiliation(s)
- Susan L Perlman
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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49
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Abstract
It is now established that a small fraction of genomic DNA does adopt the non-canonical B-DNA structure or 'unusual' DNA structure. The unusual DNA structures like DNA-hairpin, cruciform, Z-DNA, triplex and tetraplex are represented as hotspots of chromosomal breaks, homologous recombination and gross chromosomal rearrangements since they are prone to the structural alterations. Friedreich's ataxia (FRDA), the autosomal recessive degenerative disorder of nervous and muscles tissue, is caused by the massive expansion of (GAA) repeats that occur in the first intron of Frataxin gene X25 on chromosome 9q13-q21.1. The purine strand of the DNA in the expanded (GAA) repeat region folds back to form the (R.R*Y) type of triplex, which further inhibits the frataxin gene expression, and this clearly suggests that the shape of DNA is the determining factor in the cellular function. FRDA is the only disease known so far to be associated with DNA triplex. Structural characterization of GAA-containing DNA triplexes using some simple biophysical methods like UV melting, UV absorption, circular dichroic spectroscopy and electrophoretic mobility shift assay are discussed. Further, the clinical aspects and genetic analysis of FRDA patients who carry (GAA) repeat expansions are presented. The potential of some small molecules that do not favour the DNA triplex formation as therapeutics for FRDA are also briefly discussed.
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Affiliation(s)
- Moganty R Rajeswari
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi 110 029, India.
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50
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Iron dysregulation in movement disorders. Neurobiol Dis 2012; 46:1-18. [DOI: 10.1016/j.nbd.2011.12.054] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/22/2011] [Accepted: 12/31/2011] [Indexed: 01/04/2023] Open
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