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Boesch S, Indelicato E. Approval of omaveloxolone for Friedreich ataxia. Nat Rev Neurol 2024; 20:313-314. [PMID: 38570703 DOI: 10.1038/s41582-024-00957-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Affiliation(s)
- Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Elisabetta Indelicato
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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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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Indelicato E, Faserl K, Amprosi M, Nachbauer W, Schneider R, Wanschitz J, Sarg B, Boesch S. Skeletal muscle proteome analysis underpins multifaceted mitochondrial dysfunction in Friedreich's ataxia. Front Neurosci 2023; 17:1289027. [PMID: 38027498 PMCID: PMC10644315 DOI: 10.3389/fnins.2023.1289027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Friedreich's ataxia (FRDA) is a severe multisystemic disorder caused by a deficiency of the mitochondrial protein frataxin. While some aspects of FRDA pathology are developmental, the causes underlying the steady progression are unclear. The inaccessibility of key affected tissues to sampling is a main hurdle. Skeletal muscle displays a disease phenotype and may be sampled in vivo to address open questions on FRDA pathophysiology. Thus, we performed a quantitative mass spectrometry-based proteomics analysis in gastrocnemius skeletal muscle biopsies from genetically confirmed FRDA patients (n = 5) and controls. Obtained data files were processed using Proteome Discoverer and searched by Sequest HT engine against a UniProt human reference proteome database. Comparing skeletal muscle proteomics profiles between FRDA and controls, we identified 228 significant differentially expressed (DE) proteins, of which 227 were downregulated in FRDA. Principal component analysis showed a clear separation between FRDA and control samples. Interactome analysis revealed clustering of DE proteins in oxidative phosphorylation, ribosomal elements, mitochondrial architecture control, and fission/fusion pathways. DE findings in the muscle-specific proteomics suggested a shift toward fast-twitching glycolytic fibers. Notably, most DE proteins (169/228, 74%) are target of the transcription factor nuclear factor-erythroid 2. Our data corroborate a mitochondrial biosignature of FRDA, which extends beyond a mere oxidative phosphorylation failure. Skeletal muscle proteomics highlighted a derangement of mitochondrial architecture and maintenance pathways and a likely adaptive metabolic shift of contractile proteins. The present findings are relevant for the design of future therapeutic strategies and highlight the value of skeletal muscle-omics as disease state readout in FRDA.
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Affiliation(s)
- Elisabetta Indelicato
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Klaus Faserl
- Institute of Medical Biochemistry, Protein Core Facility, Medical University of Innsbruck, Innsbruck, Austria
| | - Matthias Amprosi
- Center for Rare Movement Disorders Innsbruck, 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
| | - Rainer Schneider
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), Leopold-Franzens University Innsbruck, Innsbruck, Austria
| | - Julia Wanschitz
- Laboratory of Tissue Diagnostics, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Bettina Sarg
- Institute of Medical Biochemistry, Protein Core Facility, Medical University of Innsbruck, Innsbruck, Austria
| | - Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Boesch S, Indelicato E. Experimental drugs for Friedrich's ataxia: progress and setbacks in clinical trials. Expert Opin Investig Drugs 2023; 32:967-969. [PMID: 37886821 DOI: 10.1080/13543784.2023.2276758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 10/25/2023] [Indexed: 10/28/2023]
Affiliation(s)
- Sylvia Boesch
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Elisabetta Indelicato
- Center for Rare Movement Disorders Innsbruck, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Thomas-Black G, Dumitrascu A, Garcia-Moreno H, Vallortigara J, Greenfield J, Hunt B, Walther S, Wells M, Lynch DR, Montgomery H, Giunti P. The attitude of patients with progressive ataxias towards clinical trials. Orphanet J Rare Dis 2022; 17:1. [PMID: 34983593 PMCID: PMC8729009 DOI: 10.1186/s13023-021-02091-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/17/2021] [Indexed: 12/17/2022] Open
Abstract
Background The development of new therapies may rely on the conduct of human experimentation as well as later clinical trials of therapeutic interventions. Ethical considerations seek to protect the patient from risk but few have sought to ascertain the attitude to such risk of patients with progressive debilitating or terminal conditions, for which no mitigating or curative therapies exist. Such understanding is also important if recruitment is to be maximized. We therefore sought to define the motivations for and barriers to trial participation amongst patients with progressive ataxias, as well as their condition-specific trial preferences. Methods We conducted an online survey consisting of 29 questions covering four key domains (demographics, personal motivation, drug therapy and study design) relating to the design of clinical trials. Two major ataxia charities, Ataxia UK and the Friedreich’s Ataxia Research Alliance (FARA) sent the survey to their members. Responses were analysed by disease and by ambulatory status. Results Of 342 respondents, 204 reported a diagnosis of Friedreich’s ataxia (FRDA), 55 inherited cerebellar ataxia (CA) and 70 idiopathic CA. The most important symptoms to be addressed by a trial were considered to be balance problems and ambulation, although these were superseded by speech problems in wheelchair users. Common motivations for participation were potential benefits to self and others. Reasons for non-participation included concerns about side effects, and the burden and cost of travel. Financial reimbursement for expenses was reported to be likely to increase trial engagement, Phase two trials were the most popular to participate in, and the use of a placebo arm was seen as a disincentive. Across all disease subgroups, drug repurposing trials proved popular and just under 70% of participants would be prepared to undergo intrathecal drug administration. Conclusions Knowledge of motivations for and barriers to trial participation as well as the acceptability of investigations, time commitments and routes of drug administration should inform better, more patient focused trial design. This in turn may improve recruitment and retention of participants to future trials. Supplementary Information The online version contains supplementary material available at 10.1186/s13023-021-02091-x.
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Affiliation(s)
- Gilbert Thomas-Black
- Department of Clinical and Movement Neurosciences, The Ataxia Centre, UCL Queen Square Institute of Neurology, University College London, London, UK.,National Hospital for Neurology and Neurosurgery, University College London Hospitals Foundation NHS Trust, London, UK
| | - Andrada Dumitrascu
- Department of Clinical and Movement Neurosciences, The Ataxia Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Hector Garcia-Moreno
- Department of Clinical and Movement Neurosciences, The Ataxia Centre, UCL Queen Square Institute of Neurology, University College London, London, UK.,National Hospital for Neurology and Neurosurgery, University College London Hospitals Foundation NHS Trust, London, UK
| | - Julie Vallortigara
- Department of Clinical and Movement Neurosciences, The Ataxia Centre, UCL Queen Square Institute of Neurology, University College London, London, UK
| | | | - Barry Hunt
- Ataxia UK, 12 Broadbent Close, N6 5JW, London, UK
| | - Susan Walther
- Friedreich'S Ataxia Research Alliance, 533 W Uwchlan Ave, Downingtown, PA, 19335, USA
| | - Mackenzie Wells
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - David R Lynch
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Hugh Montgomery
- Institute of Sport Exercise and Health, University College London, London, UK
| | - Paola Giunti
- Department of Clinical and Movement Neurosciences, The Ataxia Centre, UCL Queen Square Institute of Neurology, University College London, London, UK. .,National Hospital for Neurology and Neurosurgery, University College London Hospitals Foundation NHS Trust, London, UK.
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Zesiewicz TA, Hancock J, Ghanekar SD, Kuo SH, Dohse CA, Vega J. Emerging therapies in Friedreich's Ataxia. Expert Rev Neurother 2020; 20:1215-1228. [PMID: 32909841 PMCID: PMC8018609 DOI: 10.1080/14737175.2020.1821654] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 09/07/2020] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Friedreich's ataxia (FRDA) is a progressive, neurodegenerative disease that results in gait and limb ataxia, diabetes, cardiac hypertrophy, and scoliosis. At the cellular level, FRDA results in the deficiency of frataxin, a mitochondrial protein that plays a vital role in iron homeostasis and amelioration of oxidative stress. No cure currently exists for FRDA, but exciting therapeutic developments which target different parts of the pathological cascade are on the horizon. AREAS COVERED Areas covered include past and emerging therapies for FRDA, including antioxidants and mitochondrial-related agents, nuclear factor erythroid-derived 2-related factor 2 (Nrf2) activators, deuterated polyunsaturated fatty acids, iron chelators, histone deacetylase (HDAC) inhibitors, trans-activator of transcription (TAT)-frataxin, interferon gamma (IFNγ), erythropoietin, resveratrol, gene therapy, and anti-sense oligonucleotides (ASOs), among others. EXPERT OPINION While drug discovery has been challenging, new and exciting prospective treatments for FRDA are currently on the horizon, including pharmaceutical agents and gene therapy. Agents that enhance mitochondrial function, such as Nrf2 activators, dPUFAs and catalytic antioxidants, as well as novel methods of frataxin augmentation and genetic modulation will hopefully provide treatment for this devastating disease.
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Affiliation(s)
- Theresa A. Zesiewicz
- University of South Florida (USF) Department of Neurology, USF Ataxia Research Center, Tampa Florida, James A Haley Veteran’s Hospital, Tampa, Florida, USA
| | - Joshua Hancock
- University of South Florida (USF) Department of Neurology, USF Ataxia Research Center, Tampa Florida, James A Haley Veteran’s Hospital, Tampa, Florida, USA
| | - Shaila D. Ghanekar
- University of South Florida (USF) Department of Neurology, USF Ataxia Research Center, Tampa Florida, James A Haley Veteran’s Hospital, Tampa, Florida, USA
| | - Sheng-Han Kuo
- Department of Neurology, Columbia University, New York, NY, USA
- Initiative for Columbia Ataxia and Tremor, New York, NY, USA
| | - Carlos A. Dohse
- Universidad Central Del Caribe School of Medicine, Bayamon, Puerto Rico
| | - Joshua Vega
- University of South Florida (USF) Department of Neurology, USF Ataxia Research Center, Tampa Florida, James A Haley Veteran’s Hospital, Tampa, Florida, USA
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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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Consalvi S, Scarpecci C, Biava M, Poce G. Mycobacterial tryptophan biosynthesis: A promising target for tuberculosis drug development? Bioorg Med Chem Lett 2019; 29:126731. [PMID: 31627992 DOI: 10.1016/j.bmcl.2019.126731] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/17/2019] [Accepted: 10/01/2019] [Indexed: 12/25/2022]
Abstract
The biosynthetic pathways of amino acids are attractive targets for drug development against pathogens with an intracellular behavior like M. tuberculosis (Mtb). Indeed, while in the macrophages Mtb has restricted access to amino acids such as tryptophan (Trp). Auxotrophic Mtb strains, with mutations in the Trp biosynthetic pathway, showed reduced intracellular survival in cultured human and murine macrophages and failed to cause the disease in immunocompetent and immunocompromised mice. Herein we present recent efforts in the discovery of Trp biosynthesis inhibitors.
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Affiliation(s)
- Sara Consalvi
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Cristina Scarpecci
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Mariangela Biava
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy
| | - Giovanna Poce
- Department of Chemistry and Technologies of Drug, Sapienza University of Rome, piazzale A. Moro 5, 00185 Rome, Italy.
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Shen X, Beasley S, Putman JN, Li Y, Prakash TP, Rigo F, Napierala M, Corey DR. Efficient electroporation of neuronal cells using synthetic oligonucleotides: identifying duplex RNA and antisense oligonucleotide activators of human frataxin expression. RNA (NEW YORK, N.Y.) 2019; 25:1118-1129. [PMID: 31151992 PMCID: PMC6800520 DOI: 10.1261/rna.071290.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/23/2019] [Indexed: 05/08/2023]
Abstract
Oligonucleotide drugs are experiencing greater success in the clinic, encouraging the initiation of new projects. Resources are insufficient to develop every potentially important project, and persuasive experimental data using cell lines close to disease target tissue is needed to prioritize candidates. Friedreich's ataxia (FRDA) is a devastating and currently incurable disease caused by insufficient expression of the enzyme frataxin (FXN). We have previously shown that synthetic nucleic acids can activate FXN expression in human patient-derived fibroblast cells. We chose to further test these compounds in induced pluripotent stem cell-derived neuronal progenitor cells (iPSC-NPCs). Here we describe methods to deliver oligonucleotides and duplex RNAs into iPSC-NPCs using electroporation. Activation of FXN expression is potent, easily reproducible, and potencies parallel those determined using patient-derived fibroblast cells. A duplex RNA and several antisense oligonucleotides (ASOs) with different combinations of 2'-methoxyethyl (2'-MOE), 2'-fluoro (2'-F), and constrained ethyl (cEt) were active, providing multiple starting points for further development and highlighting improved potency as an important goal for preclinical development. Our data support the conclusion that ASO-mediated activation of FXN is a feasible approach for treating FRDA and that electroporation is a robust method for introducing ASOs to modulate gene expressions in neuronal cells.
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Affiliation(s)
- Xiulong Shen
- Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA
| | | | - Jennifer N Putman
- Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA
| | - Yanjie Li
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama, Birmingham, Alabama 35294, USA
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, California 92010, USA
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama, Birmingham, Alabama 35294, USA
| | - David R Corey
- Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA
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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: 30] [Impact Index Per Article: 6.0] [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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Boesch S, Indelicato E. Erythropoietin and Friedreich Ataxia: Time for a Reappraisal? Front Neurosci 2019; 13:386. [PMID: 31105516 PMCID: PMC6491891 DOI: 10.3389/fnins.2019.00386] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/04/2019] [Indexed: 12/24/2022] Open
Abstract
Friedreich ataxia (FRDA) is a rare neurological disorder due to deficiency of the mitochondrial protein frataxin. Frataxin deficiency results in impaired mitochondrial function and iron deposition in affected tissues. Erythropoietin (EPO) is a cytokine which was mostly known as a key regulator of erythropoiesis until cumulative evidence showed additional neurotrophic and neuroprotective properties. These features offered the rationale for advancement of EPO in clinical trials in different neurological disorders in the past years, including FRDA. Several mechanisms of action of EPO may be beneficial in FRDA. First of all, EPO exposure results in frataxin upregulation in vitro and in vivo. By promoting erythropoiesis, EPO influences iron metabolism and induces shifts in iron pool which may ameliorate conditions of free iron excess and iron accumulation. Furthermore, EPO signaling is crucial for mitochondrial gene activation and mitochondrial biogenesis. Up to date nine clinical trials investigated the effects of EPO and derivatives in FRDA. The majority of these studies had a proof-of-concept design. Considering the natural history of FRDA, all of them were too short in duration and not powered for clinical changes. However, these studies addressed significant issues in the treatment with EPO, such as (1) the challenge of the dose finding, (2) stability of frataxin up-regulation, (3) continuous versus intermittent stimulation with EPO/regimen, or (4) tissue changes after EPO exposure in humans in vivo (muscle biopsy, brain imaging). Despite several clinical trials in the past, no treatment is available for the treatment of FRDA. Current lines of research focus on gene therapy, frataxin replacement strategies and on regulation of key metabolic checkpoints such as NrF2. Due to potential crosstalk with all these mechanisms, interventions on the EPO pathway still represent a valuable research field. The recent development of small EPO mimetics which maintain cytoprotective properties without erythropoietic action may open a new era in EPO research for the treatment of FRDA.
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Affiliation(s)
- Sylvia Boesch
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
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Zhang S, Napierala M, Napierala JS. Therapeutic Prospects for Friedreich's Ataxia. Trends Pharmacol Sci 2019; 40:229-233. [PMID: 30905359 PMCID: PMC6826337 DOI: 10.1016/j.tips.2019.02.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/01/2019] [Accepted: 02/04/2019] [Indexed: 02/07/2023]
Abstract
Friedreich's ataxia (FRDA) is a progressive disease affecting multiple organs that is caused by systemic insufficiency of the mitochondrial protein frataxin. Current therapeutic strategies aim to elevate frataxin levels and/or alleviate the consequences of frataxin deficiency. Recent significant advances in the FRDA therapeutic pipeline are bringing patients closer to a cure.
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Affiliation(s)
- Siyuan Zhang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), 1825 University Boulevard, Birmingham, AL 35294, USA
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), 1825 University Boulevard, Birmingham, AL 35294, USA
| | - Jill S Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham (UAB), 1825 University Boulevard, Birmingham, AL 35294, USA.
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Shen X, Kilikevicius A, O'Reilly D, Prakash TP, Damha MJ, Rigo F, Corey DR. Activating frataxin expression by single-stranded siRNAs targeting the GAA repeat expansion. Bioorg Med Chem Lett 2018; 28:2850-2855. [PMID: 30076049 PMCID: PMC6129981 DOI: 10.1016/j.bmcl.2018.07.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 11/18/2022]
Abstract
Friedreich's ataxia (FRDA) is an incurable neurodegenerative disorder caused by reduced expression of the mitochondrial protein frataxin (FXN). The genetic cause of the disease is an expanded GAA repeat within the FXN gene. Agents that increase expression of FXN protein are a potential approach to therapy. We previously described anti-trinucleotide GAA duplex RNAs (dsRNAs) and antisense oligonucleotides (ASOs) that activate FXN protein expression in multiple patient derived cell lines. Here we test two distinct series of compounds for their ability to increase FXN expression. ASOs with butane linkers showed low potency, which is consistent with the low Tm values and suggesting that flexible conformation impairs activity. By contrast, single-stranded siRNAs (ss-siRNAs) that combine the strengths of dsRNA and ASO approaches had nanomolar potencies. ss-siRNAs provide an additional option for developing nucleic acid therapeutics to treat FRDA.
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Affiliation(s)
- Xiulong Shen
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States; Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States
| | - Audrius Kilikevicius
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States; Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States
| | - Daniel O'Reilly
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | | | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92010, United States
| | - David R Corey
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States; Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States.
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