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Eisel MLS, Burns M, Ashizawa T, Byrne B, Corti M, Subramony SH. Emerging therapies in hereditary ataxias. Trends Mol Med 2024:S1471-4914(24)00194-1. [PMID: 39153956 DOI: 10.1016/j.molmed.2024.07.008] [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: 05/21/2024] [Revised: 07/15/2024] [Accepted: 07/22/2024] [Indexed: 08/19/2024]
Abstract
Recent investigations have defined the pathophysiological basis of many hereditary ataxias (HAs), including loss-of-function as well as gain-of-function mechanisms at either the RNA or protein level. Preclinical studies have assessed gene editing, gene and protein replacement, gene enhancement, and gene knockdown strategies. Methodologies include viral vector delivery of genes, oligonucleotide therapies, cell-penetrating peptides, synthetic transcription factors, and technologies to deliver therapies to defined targets. In this review, we focus on Friedreich ataxia (FRDA) and the polyglutamine ataxias in which translational research is active. However, much remains to be done to identify safe and effective molecules, create ideal delivery methods, and perform innovative clinical trials to prove the safety and efficacy of treatments for these rare but devastating diseases.
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Affiliation(s)
- Mallory L S Eisel
- Department of Neurology and the Fixel Institute for Neurological Disorders, University of Florida College of Medicine, Gainesville, FL, USA
| | - Matthew Burns
- Department of Neurology and the Fixel Institute for Neurological Disorders, University of Florida College of Medicine, Gainesville, FL, USA
| | - Tetsuo Ashizawa
- Stanley H. Appel Department of Neurology, Weill Cornell Medicine at Houston Methodist Hospital, Houston, TX, USA
| | - Barry Byrne
- Department of Pediatrics and the Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Manuela Corti
- Department of Pediatrics and the Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL, USA
| | - Sub H Subramony
- Department of Neurology and the Fixel Institute for Neurological Disorders, University of Florida College of Medicine, Gainesville, FL, USA.
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2
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Mosbach V, Puccio H. A multiple animal and cellular models approach to study frataxin deficiency in Friedreich Ataxia. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119809. [PMID: 39134123 DOI: 10.1016/j.bbamcr.2024.119809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 08/01/2024] [Accepted: 08/02/2024] [Indexed: 08/15/2024]
Abstract
Friedreich's ataxia (FA) is one of the most frequent inherited recessive ataxias characterized by a progressive sensory and spinocerebellar ataxia. The main causative mutation is a GAA repeat expansion in the first intron of the frataxin (FXN) gene which leads to a transcriptional silencing of the gene resulting in a deficit in FXN protein. The nature of the mutation (an unstable GAA expansion), as well as the multi-systemic nature of the disease (with neural and non-neural sites affected) make the generation of models for Friedreich's ataxia quite challenging. Over the years, several cellular and animal models for FA have been developed. These models are all complementary and possess their own strengths to investigate different aspects of the disease, such as the epigenetics of the locus or the pathophysiology of the disease, as well as being used to developed novel therapeutic approaches. This review will explore the recent advancements in the different mammalian models developed for FA.
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Affiliation(s)
- Valentine Mosbach
- Institut NeuroMyoGene-PGNM UCBL-CNRS UMR5261 INSERM U1315, Lyon, France
| | - Hélène Puccio
- Institut NeuroMyoGene-PGNM UCBL-CNRS UMR5261 INSERM U1315, Lyon, France.
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3
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Gunther K, Lynch DR. Pharmacotherapeutic strategies for Friedreich Ataxia: a review of the available data. Expert Opin Pharmacother 2024; 25:529-539. [PMID: 38622054 DOI: 10.1080/14656566.2024.2343782] [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: 02/05/2024] [Accepted: 04/12/2024] [Indexed: 04/17/2024]
Abstract
INTRODUCTION Friedreich ataxia (FRDA) is a rare autosomal recessive disease, marked by loss of coordination as well as impaired neurological, endocrine, orthopedic, and cardiac function. There are many symptomatic medications for FRDA, and many clinical trials have been performed, but only one FDA-approved medication exists. AREAS COVERED The relative absence of the frataxin protein (FXN) in FRDA causes mitochondrial dysfunction, resulting in clinical manifestations. Currently, the only approved treatment for FRDA is an Nrf2 activator called omaveloxolone (Skyclarys). Patients with FRDA also rely on various symptomatic medications for treatment. Because there is only one approved medication for FRDA, clinical trials continue to advance in FRDA. Although some trials have not met their endpoints, many current and upcoming clinical trials provide exciting possibilities for the treatment of FRDA. EXPERT OPINION The approval of omaveloxolone provides a major advance in FRDA therapeutics. Although well tolerated, it is not curative. Reversal of deficient frataxin levels with gene therapy, protein replacement, or epigenetic approaches provides the most likely prospect for enduring, disease-modifying therapy in the future.
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Affiliation(s)
- Katherine Gunther
- Friedreich Ataxia Program, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - David R Lynch
- Friedreich Ataxia Program, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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4
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Pilotto F, Del Bondio A, Puccio H. Hereditary Ataxias: From Bench to Clinic, Where Do We Stand? Cells 2024; 13:319. [PMID: 38391932 PMCID: PMC10886822 DOI: 10.3390/cells13040319] [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: 12/01/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024] Open
Abstract
Cerebellar ataxias are a wide heterogeneous group of movement disorders. Within this broad umbrella of diseases, there are both genetics and sporadic forms. The clinical presentation of these conditions can exhibit a diverse range of symptoms across different age groups, spanning from pure cerebellar manifestations to sensory ataxia and multisystemic diseases. Over the last few decades, advancements in our understanding of genetics and molecular pathophysiology related to both dominant and recessive ataxias have propelled the field forward, paving the way for innovative therapeutic strategies aimed at preventing and arresting the progression of these diseases. Nevertheless, the rarity of certain forms of ataxia continues to pose challenges, leading to limited insights into the etiology of the disease and the identification of target pathways. Additionally, the lack of suitable models hampers efforts to comprehensively understand the molecular foundations of disease's pathophysiology and test novel therapeutic interventions. In the following review, we describe the epidemiology, symptomatology, and pathological progression of hereditary ataxia, including both the prevalent and less common forms of these diseases. Furthermore, we illustrate the diverse molecular pathways and therapeutic approaches currently undergoing investigation in both pre-clinical studies and clinical trials. Finally, we address the existing and anticipated challenges within this field, encompassing both basic research and clinical endeavors.
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Affiliation(s)
- Federica Pilotto
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
| | - Andrea Del Bondio
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
| | - Hélène Puccio
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
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Perfitt TL, Huichalaf C, Gooch R, Kuperman A, Ahn Y, Chen X, Ullas S, Hirenallur-Shanthappa D, Zhan Y, Otis D, Whiteley LO, Bulawa C, Martelli A. A modified mouse model of Friedreich's ataxia with conditional Fxn allele homozygosity delays onset of cardiomyopathy. Am J Physiol Heart Circ Physiol 2024; 326:H357-H369. [PMID: 38038720 DOI: 10.1152/ajpheart.00496.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/02/2023]
Abstract
Friedreich's ataxia (FA) is an autosomal recessive disorder caused by a deficiency in frataxin (FXN), a mitochondrial protein that plays a critical role in the synthesis of iron-sulfur clusters (Fe-S), vital inorganic cofactors necessary for numerous cellular processes. FA is characterized by progressive ataxia and hypertrophic cardiomyopathy, with cardiac dysfunction as the most common cause of mortality in patients. Commonly used cardiac-specific mouse models of FA use the muscle creatine kinase (MCK) promoter to express Cre recombinase in cardiomyocytes and striated muscle cells in mice with one conditional Fxn allele and one floxed-out/null allele. These mice quickly develop cardiomyopathy that becomes fatal by 9-11 wk of age. Here, we generated a cardiac-specific model with floxed Fxn allele homozygosity (MCK-Fxnflox/flox). MCK-Fxnflox/flox mice were phenotypically normal at 9 wk of age, despite no detectable FXN protein expression. Between 13 and 15 wk of age, these mice began to display progressive cardiomyopathy, including decreased ejection fraction and fractional shortening and increased left ventricular mass. MCK-Fxnflox/flox mice began to lose weight around 16 wk of age, characteristically associated with heart failure in other cardiac-specific FA models. By 18 wk of age, MCK-Fxnflox/flox mice displayed elevated markers of Fe-S deficiency, cardiac stress and injury, and cardiac fibrosis. This modified model reproduced important pathophysiological and biochemical features of FA over a longer timescale than previous cardiac-specific mouse models, offering a larger window for studying potential therapeutics.NEW & NOTEWORTHY Previous cardiac-specific frataxin knockout models exhibit rapid and fatal cardiomyopathy by 9 wk of age. This severe phenotype poses challenges for the design and execution of intervention studies. We introduce an alternative cardiac-specific model, MCK-Fxnflox/flox, with increased longevity and delayed onset of all major phenotypes. These phenotypes develop to the same severity as previous models. Thus, this new model provides the same cardiomyopathy-associated mortality with a larger window for potential studies.
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Affiliation(s)
- Tyler L Perfitt
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Claudia Huichalaf
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Renea Gooch
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Anna Kuperman
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Youngwook Ahn
- Target Sciences, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Xian Chen
- Comparative Medicine, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Soumya Ullas
- Comparative Medicine, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Dinesh Hirenallur-Shanthappa
- Comparative Medicine, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Yutian Zhan
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Diana Otis
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Laurence O Whiteley
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Christine Bulawa
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
| | - Alain Martelli
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer, Incorporated, Cambridge, Massachusetts, United States
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Ast T, Wang H, Marutani E, Nagashima F, Malhotra R, Ichinose F, Mootha VK. Continuous, but not intermittent, regimens of hypoxia prevent and reverse ataxia in a murine model of Friedreich's ataxia. Hum Mol Genet 2023; 32:2600-2610. [PMID: 37260376 PMCID: PMC10407700 DOI: 10.1093/hmg/ddad091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 05/08/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023] Open
Abstract
Friedreich's ataxia (FA) is a devastating, multi-systemic neurodegenerative disease affecting thousands of people worldwide. We previously reported that oxygen is a key environmental variable that can modify FA pathogenesis. In particular, we showed that chronic, continuous normobaric hypoxia (11% FIO2) prevents ataxia and neurological disease in a murine model of FA, although it did not improve cardiovascular pathology or lifespan. Here, we report the pre-clinical evaluation of seven 'hypoxia-inspired' regimens in the shFxn mouse model of FA, with the long-term goal of designing a safe, practical and effective regimen for clinical translation. We report three chief results. First, a daily, intermittent hypoxia regimen (16 h 11% O2/8 h 21% O2) conferred no benefit and was in fact harmful, resulting in elevated cardiac stress and accelerated mortality. The detrimental effect of this regimen is likely owing to transient tissue hyperoxia that results when daily exposure to 21% O2 combines with chronic polycythemia, as we could blunt this toxicity by pharmacologically inhibiting polycythemia. Second, we report that more mild regimens of chronic hypoxia (17% O2) confer a modest benefit by delaying the onset of ataxia. Third, excitingly, we show that initiating chronic, continuous 11% O2 breathing once advanced neurological disease has already started can rapidly reverse ataxia. Our studies showcase both the promise and limitations of candidate hypoxia-inspired regimens for FA and underscore the need for additional pre-clinical optimization before future translation into humans.
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Affiliation(s)
- Tslil Ast
- Broad Institute, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Hong Wang
- Broad Institute, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Eizo Marutani
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Fumiaki Nagashima
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Rajeev Malhotra
- Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Fumito Ichinose
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Vamsi K Mootha
- Broad Institute, Cambridge, MA 02142, USA
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
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Yaméogo P, Gérard C, Majeau N, Tremblay JP. Removal of the GAA repeat in the heart of a Friedreich's ataxia mouse model using CjCas9. Gene Ther 2023; 30:612-619. [PMID: 36781946 DOI: 10.1038/s41434-023-00387-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/12/2023] [Accepted: 01/27/2023] [Indexed: 02/15/2023]
Abstract
Most Friedreich ataxia (FRDA) cases are caused by the elongation of the GAA repeat (GAAr) sequence in the first intron of the FXN gene, leading to a decrease of the frataxin protein expression. Deletion of this GAAr with CRISPR/Cas9 technology leads to an increase in frataxin expression in vitro. We are therefore aiming to develop FRDA treatment based on the deletion of GAAr with CRISPR/Cas9 technology using a single AAV expressing a small Cas9 (CjCas9) and two single guide RNAs (sgRNAs) targeting the FXN gene. This AAV was intraperitoneally administrated to YG8sR (250-300 GAAr) and to YG8-800 (800 GAAr) mice. DNA and RNA were extracted from different organs a month later. PCR amplification of part of intron 1 of the FXN gene detected some GAAr deletion in some cells in heart and liver of both mouse models, but the editing rate was not sufficient to cause an increase in frataxin mRNA in the heart. However, the correlation observed between the editing rate and the distribution of AAV suggests a possible therapy based on the removal of the GAAr with a better delivery tool of the CRISPR/Cas9 system.
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Affiliation(s)
- Pouiré Yaméogo
- Centre de Recherche du CHU de Québec-Université Laval, Québec city, QC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec city, QC, Canada
| | - Catherine Gérard
- Centre de Recherche du CHU de Québec-Université Laval, Québec city, QC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec city, QC, Canada
| | - Nathalie Majeau
- Centre de Recherche du CHU de Québec-Université Laval, Québec city, QC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec city, QC, Canada
| | - Jacques P Tremblay
- Centre de Recherche du CHU de Québec-Université Laval, Québec city, QC, Canada.
- Département de Médecine Moléculaire, Université Laval, Québec city, QC, Canada.
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8
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Munoz-Zuluaga C, Gertz M, Yost-Bido M, Greco A, Gorman N, Chen A, Kooner V, Rosenberg JB, De BP, Kaminsky SM, Borczuk A, Ricart Arbona RJ, Martin HR, Monette S, Khanna R, Barth JA, Crystal RG, Sondhi D. Identification of Safe and Effective Intravenous Dose of AAVrh.10hFXN to Treat the Cardiac Manifestations of Friedreich's Ataxia. Hum Gene Ther 2023; 34:605-615. [PMID: 37166361 PMCID: PMC10354731 DOI: 10.1089/hum.2023.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/16/2023] [Indexed: 05/12/2023] Open
Abstract
Friedreich's ataxia (FA) is a life-threatening autosomal recessive disorder characterized by neurological and cardiac dysfunction. Arrhythmias and heart failure are the main cause of premature death. From prior studies in murine models of FA, adeno-associated virus encoding the normal human frataxin gene (AAVrh.10hFXN) effectively treated the cardiac manifestations of the disease. However, the therapeutic dose window is limited by high level of human frataxin (hFXN) gene expression associated with toxicity. As a therapeutic goal, since FA heterozygotes have no clinical manifestations of FA, we estimated the level of frataxin (FXN) necessary to convert the heart of a homozygote to that of a heterozygote. In noncardiac cells, FA heterozygotes have 30-80% of normal FXN levels (17.7-47.2 ng/mg, average 32.5 ng/mg) and FA homozygotes 2-30% normal levels (1.2-17.7 ng/mg, average 9.4 ng/mg). Therefore, an AAV vector would need to augment endogenous in an FA homozygote by >8.3 ng/mg. To determine the required dose of AAVrh.10hFXN, we administered 1.8 × 1011, 5.7 × 1011, or 1.8 × 1012 gc/kg of AAVrh.10hFXN intravenously (IV) to muscle creatine kinase (mck)-Cre conditional knockout Fxn mice, a cardiac and skeletal FXN knockout model. The minimally effective dose was 5.7 × 1011 gc/kg, resulting in cardiac hFXN levels of 6.1 ± 4.2 ng/mg and a mild (p < 0.01 compared with phosphate-buffered saline controls) improvement in mortality. A dose of 1.8 × 1012 gc/kg resulted in cardiac hFXN levels of 33.7 ± 6.4 ng/mg, a significant improvement in ejection fraction and fractional shortening (p < 0.05, both comparisons) and a 21.5% improvement in mortality (p < 0.001). To determine if the significantly effective dose of 1.8 × 1012 gc/kg could achieve human FA heterozygote levels in a large animal, this dose was administered IV to nonhuman primates. After 12 weeks, the vector-expressed FXN in the heart was 17.8 ± 4.9 ng/mg, comparable to the target human levels. These data identify both minimally and significantly effective therapeutic doses that are clinically relevant for the treatment of the cardiac manifestations of FA.
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Affiliation(s)
| | - Monica Gertz
- Department of Genetic Medicine, New York, New York, USA
| | | | | | | | - Alvin Chen
- Department of Genetic Medicine, New York, New York, USA
| | - Vikrum Kooner
- Department of Genetic Medicine, New York, New York, USA
| | | | - Bishnu P. De
- Department of Genetic Medicine, New York, New York, USA
| | | | - Alain Borczuk
- Department of Pathology, Weill Cornell Medicine, New York, New York, USA
| | - Rodolfo J. Ricart Arbona
- Center for Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Heather R. Martin
- Center for Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | - Sebastien Monette
- Center for Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medicine, New York, New York, USA
| | | | | | | | - Dolan Sondhi
- Department of Genetic Medicine, New York, New York, USA
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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: 10] [Impact Index Per Article: 10.0] [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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10
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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: 21] [Impact Index Per Article: 10.5] [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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11
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Tong WH, Ollivierre H, Noguchi A, Ghosh MC, Springer DA, Rouault TA. Hyperactivation of mTOR and AKT in a cardiac hypertrophy animal model of Friedreich ataxia. Heliyon 2022; 8:e10371. [PMID: 36061025 PMCID: PMC9433723 DOI: 10.1016/j.heliyon.2022.e10371] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 02/28/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022] Open
Abstract
Cardiomyopathy is a primary cause of death in Friedreich ataxia (FRDA) patients with defective iron-sulfur cluster (ISC) biogenesis due to loss of functional frataxin and in rare patients with functional loss of other ISC biogenesis factors. The mechanistic target of rapamycin (mTOR) and AKT signaling cascades that coordinate eukaryotic cell growth and metabolism with environmental inputs, including nutrients and growth factors, are crucial regulators of cardiovascular growth and homeostasis. We observed increased phosphorylation of AKT and dysregulation of multiple downstream effectors of mTORC1, including S6K1, S6, ULK1 and 4EBP1, in a cardiac/skeletal muscle specific FRDA conditional knockout (cKO) mouse model and in human cell lines depleted of ISC biogenesis factors. Knockdown of several mitochondrial metabolic proteins that are downstream targets of ISC biogenesis, including lipoyl synthase and subunit B of succinate dehydrogenase, also resulted in activation of mTOR and AKT signaling, suggesting that mTOR and AKT hyperactivations are part of the metabolic stress response to ISC deficiencies. Administration of rapamycin, a specific inhibitor of mTOR signaling, enhanced the survival of the Fxn cKO mice, providing proof of concept for the potential of mTOR inhibition to ameliorate cardiac disease in patients with defective ISC biogenesis. However, AKT phosphorylation remained high in rapamycin-treated Fxn cKO hearts, suggesting that parallel mTOR and AKT inhibition might be necessary to further improve the lifespan and healthspan of ISC deficient individuals.
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Affiliation(s)
- Wing-Hang Tong
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
| | - Hayden Ollivierre
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
| | - Audrey Noguchi
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, United States
| | - Manik C. Ghosh
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
| | - Danielle A. Springer
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, United States
| | - Tracey A. Rouault
- Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20892, United States
- Corresponding author.
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12
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Affiliation(s)
- R. Mark Payne
- Indiana University School of Medicine, Wells Center for Pediatric Research, 1044 West Walnut, R4302b, Indianapolis, IN 46202, USA
- Corresponding author R. Mark Payne, MD, Indiana University School of Medicine, Wells Center for Pediatric Research, 1044 West Walnut, R4302b, Indianapolis, IN 46202, USA.
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13
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Mercado-Ayón E, Warren N, Halawani S, Rodden LN, Ngaba L, Dong YN, Chang JC, Fonck C, Mavilio F, Lynch DR, Lin H. Cerebellar Pathology in an Inducible Mouse Model of Friedreich Ataxia. Front Neurosci 2022; 16:819569. [PMID: 35401081 PMCID: PMC8987918 DOI: 10.3389/fnins.2022.819569] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by deficiency of the mitochondrial protein frataxin. Lack of frataxin causes neuronal loss in various areas of the CNS and PNS. In particular, cerebellar neuropathology in FRDA patients includes loss of large principal neurons and synaptic terminals in the dentate nucleus (DN), and previous studies have demonstrated early synaptic deficits in the Knockin-Knockout mouse model of FRDA. However, the exact correlation of frataxin deficiency with cerebellar neuropathology remains unclear. Here we report that doxycycline-induced frataxin knockdown in a mouse model of FRDA (FRDAkd) leads to synaptic cerebellar degeneration that can be partially reversed by AAV8-mediated frataxin restoration. Loss of cerebellar Purkinje neurons and large DN principal neurons are observed in the FRDAkd mouse cerebellum. Levels of the climbing fiber-specific glutamatergic synaptic marker VGLUT2 decline starting at 4 weeks after dox induction, whereas levels of the parallel fiber-specific synaptic marker VGLUT1 are reduced by 18-weeks. These findings suggest initial selective degeneration of climbing fiber synapses followed by loss of parallel fiber synapses. The GABAergic synaptic marker GAD65 progressively declined during dox induction in FRDAkd mice, while GAD67 levels remained unaltered, suggesting specific roles for frataxin in maintaining cerebellar synaptic integrity and function during adulthood. Expression of frataxin following AAV8-mediated gene transfer partially restored VGLUT1/2 levels. Taken together, our findings show that frataxin knockdown leads to cerebellar degeneration in the FRDAkd mouse model, suggesting that frataxin helps maintain cerebellar structure and function.
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Affiliation(s)
- Elizabeth Mercado-Ayón
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Nathan Warren
- Department of Pediatrics and Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Sarah Halawani
- Department of Pediatrics and Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Layne N. Rodden
- Department of Pediatrics and Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Lucie Ngaba
- Department of Pediatrics and Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Yi Na Dong
- Department of Pediatrics and Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | | | - Carlos Fonck
- Audentes Therapeutics, San Francisco, CA, United States
| | - Fulvio Mavilio
- Audentes Therapeutics, San Francisco, CA, United States
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - David R. Lynch
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Department of Pediatrics and Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- *Correspondence: David R. Lynch, ;
| | - Hong Lin
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Hong Lin,
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14
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Huichalaf C, Perfitt TL, Kuperman A, Gooch R, Kovi RC, Brenneman KA, Chen X, Hirenallur-Shanthappa D, Ma T, Assaf BT, Pardo I, Franks T, Monarski L, Cheng TW, Le K, Su C, Somanathan S, Whiteley LO, Bulawa C, Pregel MJ, Martelli A. In vivo overexpression of frataxin causes toxicity mediated by iron-sulfur cluster deficiency. Mol Ther Methods Clin Dev 2022; 24:367-378. [PMID: 35252470 PMCID: PMC8866050 DOI: 10.1016/j.omtm.2022.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 02/04/2022] [Indexed: 12/25/2022]
Abstract
Friedreich's ataxia is a rare disorder resulting from deficiency of frataxin, a mitochondrial protein implicated in the synthesis of iron-sulfur clusters. Preclinical studies in mice have shown that gene therapy is a promising approach to treat individuals with Friedreich's ataxia. However, a recent report provided evidence that AAVrh10-mediated overexpression of frataxin could lead to cardiotoxicity associated with mitochondrial dysfunction. While evaluating an AAV9-based frataxin gene therapy using a chicken β-actin promoter, we showed that toxic overexpression of frataxin could be reached in mouse liver and heart with doses between 1 × 1013 and 1 × 1014 vg/kg. In a mouse model of cardiac disease, these doses only corrected cardiac dysfunction partially and transiently and led to adverse findings associated with iron-sulfur cluster deficiency in liver. We demonstrated that toxicity required frataxin's primary function by using a frataxin construct bearing the N146K mutation, which impairs binding to the iron-sulfur cluster core complex. At the lowest tested dose, we observed moderate liver toxicity that was accompanied by progressive loss of transgene expression and liver regeneration. Together, our data provide insights into the toxicity of frataxin overexpression that should be considered in the development of a gene therapy approach for Friedreich's ataxia.
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Affiliation(s)
- Claudia Huichalaf
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Tyler L Perfitt
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Anna Kuperman
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Renea Gooch
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Ramesh C Kovi
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Karrie A Brenneman
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Xian Chen
- Comparative Medicine, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | | | - Tiffany Ma
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Basel T Assaf
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Ingrid Pardo
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Tania Franks
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Laura Monarski
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Ting-Wen Cheng
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Kevin Le
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Chunyan Su
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Suryanarayan Somanathan
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Laurence O Whiteley
- Drug Safety Research and Development, Worldwide Research, Development and Medical, Pfizer Inc., Cambridge, MA 02139, USA
| | - Christine Bulawa
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Marko J Pregel
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
| | - Alain Martelli
- Rare Disease Research Unit, Worldwide Research, Development and Medical, Pfizer Inc., 610 Main Street, Cambridge, MA 02139, USA
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15
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Jayakumar D, S Narasimhan KK, Periandavan K. Triad role of hepcidin, ferroportin, and Nrf2 in cardiac iron metabolism: From health to disease. J Trace Elem Med Biol 2022; 69:126882. [PMID: 34710708 DOI: 10.1016/j.jtemb.2021.126882] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/29/2021] [Accepted: 10/19/2021] [Indexed: 11/28/2022]
Abstract
Iron is an essential trace element required for several vital physiological and developmental processes, including erythropoiesis, bone, and neuronal development. Iron metabolism and oxygen homeostasis are interlinked to perform a vital role in the functionality of the heart. The metabolic machinery of the heart utilizes almost 90 % of oxygen through the electron transport chain. To handle this tremendous level of oxygen, the iron metabolism in the heart is utmost crucial. Iron availability to the heart is therefore tightly regulated by (i) the hepcidin/ferroportin axis, which controls dietary iron absorption, storage, and recycling, and (ii) iron regulatory proteins 1 and 2 (IRP1/2) via hypoxia inducible factor 1 (HIF1) pathway. Despite iron being vital to the heart, recent investigations have demonstrated that iron imbalance is a common manifestation in conditions of heart failure (HF), since free iron readily transforms between Fe2+ and Fe3+via the Fenton reaction, leading to reactive oxygen species (ROS) production and oxidative damage. Therefore, to combat iron-mediated oxidative stress, targeting Nrf2/ARE antioxidant signaling is rational. The involvement of Nrf2 in regulating several genes engaged in heme synthesis, iron storage, and iron export is beginning to be uncovered. Consequently, it is possible that Nrf2/hepcidin/ferroportin might act as an epicenter connecting iron metabolism to redox alterations. However, the mechanism bridging the two remains obscure. In this review, we tried to summarize the contemporary insight of how cardiomyocytes regulate intracellular iron levels and discussed the mechanisms linking cardiac dysfunction with iron imbalance. Further, we emphasized the impact of Nrf2 on the interplay between systemic/cardiac iron control in the context of heart disease, particularly in myocardial ischemia and HF.
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Affiliation(s)
- Deepthy Jayakumar
- Department of Medical Biochemistry, Dr. ALM Post Graduate Institute for Basic Medical Sciences, University of Madras, Chennai, 600113, Tamil Nadu, India
| | - Kishore Kumar S Narasimhan
- Department of Pharmacology and Neurosciences, Creighton University, 2500 California Plaza, Omaha, NE, USA
| | - Kalaiselvi Periandavan
- Department of Medical Biochemistry, Dr. ALM Post Graduate Institute for Basic Medical Sciences, University of Madras, Chennai, 600113, Tamil Nadu, India.
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16
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Vásquez-Trincado C, Patel M, Sivaramakrishnan A, Bekeová C, Anderson-Pullinger L, Wang N, Tang HY, Seifert EL. Adaptation of the heart to Frataxin depletion: Evidence that integrated stress response can predominate over mTORC1 activation. Hum Mol Genet 2021; 33:ddab216. [PMID: 34550363 PMCID: PMC11000666 DOI: 10.1093/hmg/ddab216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/12/2022] Open
Abstract
Friedreich's ataxia (FRDA) is an inherited disorder caused by depletion of frataxin (FXN), a mitochondrial protein required for iron-sulfur cluster (ISC) biogenesis. Cardiac dysfunction is the main cause of death. Yet pathogenesis, and, more generally, how the heart adapts to FXN loss, remain poorly understood, though are expected to be linked to an energy deficit. We modified a transgenic (TG) mouse model of inducible FXN depletion that permits phenotypic evaluation of the heart at different FXN levels, and focused on substrate-specific bioenergetics and stress signaling. When FXN protein in the TG heart was 17% of normal, bioenergetics and signaling were not different from control. When, 8 weeks later, FXN was ~ 97% depleted in the heart, TG heart mass and cardiomyocyte cross-sectional area were less, without evidence of fibrosis or apoptosis. mTORC1 signaling was activated, as was the integrated stress response, evidenced by greater phosphorylation of eIF2α relative to total eIF2α, and decreased protein translation. We interpret these results to suggest that, in TG hearts, an anabolic stimulus was constrained by eIF2α phosphorylation. Cardiac contractility was maintained in the 97%-FXN-depleted hearts, possibly contributed by an unexpected preservation of β-oxidation, though pyruvate oxidation was lower. Bioenergetics alterations were matched by changes in the mitochondrial proteome, including a non-uniform decrease in abundance of ISC-containing proteins. Altogether, these findings suggest that the FXN depleted heart can suppress a major ATP demanding process such as protein translation, which, together with some preservation of β-oxidation, could be adaptive, at least in the short term.
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Affiliation(s)
- César Vásquez-Trincado
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Monika Patel
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Aishwarya Sivaramakrishnan
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Carmen Bekeová
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Lauren Anderson-Pullinger
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Nadan Wang
- Center for Translational Medicine, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, The Wistar Institute, Philadelphia, PA 19104, United States
| | - Erin L Seifert
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
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17
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Frempong B, Wilson RB, Schadt K, Lynch DR. The Role of Serum Levels of Neurofilament Light (NfL) Chain as a Biomarker in Friedreich Ataxia. Front Neurosci 2021; 15:653241. [PMID: 33737864 PMCID: PMC7960909 DOI: 10.3389/fnins.2021.653241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/05/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Bernice Frempong
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Departments of Neurology and Pediatrics, University of Pennsylvania, Philadelphia, PA, United States
| | - Robert B Wilson
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Kimberly Schadt
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Departments of Neurology and Pediatrics, University of Pennsylvania, Philadelphia, PA, United States
| | - David R Lynch
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Departments of Neurology and Pediatrics, University of Pennsylvania, Philadelphia, PA, United States
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18
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Lynch DR, Johnson J. Omaveloxolone: potential new agent for Friedreich ataxia. Neurodegener Dis Manag 2021; 11:91-98. [PMID: 33430645 DOI: 10.2217/nmt-2020-0057] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Friedreich ataxia is a slowly progressive neurodegenerative disorder leading to ataxia, dyscoordination, dysarthria and in many individuals vision and hearing loss. It is associated with cardiomyopathy, the leading cause of death in Friedreich ataxia (FRDA), diabetes and scoliosis. There are no approved therapies, but elucidation of the pathophysiology of FRDA suggest that agents that increase the activity of the transcription factor Nrf2 may provide a mechanism for ameliorating disease progression or severity. In this work, we review the evidence for use of omaveloxolone in FRDA from recent clinical trials. Though not at present approved for any indication, the present data suggest that this agent acting though increases in Nrf2 activity may provide a novel therapy for FRDA.
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Affiliation(s)
- David R Lynch
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Department of Neurology & Pediatrics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joseph Johnson
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Department of Systems Pharmacology & Translational Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
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19
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Belbellaa B, Reutenauer L, Messaddeq N, Monassier L, Puccio H. High Levels of Frataxin Overexpression Lead to Mitochondrial and Cardiac Toxicity in Mouse Models. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 19:120-138. [PMID: 33209958 PMCID: PMC7648087 DOI: 10.1016/j.omtm.2020.08.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/27/2020] [Indexed: 12/18/2022]
Abstract
Friedreich ataxia (FA) is currently an incurable inherited mitochondrial disease caused by reduced levels of frataxin (FXN). Cardiac dysfunction is the main cause of premature death in FA. Adeno-associated virus (AAV)-mediated gene therapy constitutes a promising approach for FA, as demonstrated in cardiac and neurological mouse models. While the minimal therapeutic level of FXN protein to be restored and biodistribution have recently been defined for the heart, it is unclear if FXN overexpression could be harmful. Indeed, depending on the vector delivery route and dose administered, the resulting FXN protein level could reach very high levels in the heart, cerebellum, or off-target organs such as the liver. The present study demonstrates safety of FXN cardiac overexpression up to 9-fold the normal endogenous level but significant toxicity to the mitochondria and heart above 20-fold. We show gradual severity with increasing FXN overexpression, ranging from subclinical cardiotoxicity to left ventricle dysfunction. This appears to be driven by impairment of the mitochondria respiratory chain and ultrastructure, which leads to cardiomyocyte subcellular disorganization, cell death, and fibrosis. Overall, this study underlines the need, during the development of gene therapy approaches, to consider appropriate vector expression level, long-term safety, and biomarkers to monitor such events.
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Affiliation(s)
- Brahim Belbellaa
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
| | - Laurence Reutenauer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
| | - Nadia Messaddeq
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
| | - Laurent Monassier
- Laboratoire de Pharmacologie et Toxicologie NeuroCardiovasculaire EA7296, Faculté de Médecine, Strasbourg 67085, France
| | - Hélène Puccio
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.,Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch 67404, France.,Centre National de la Recherche Scientifique, UMR7104, Illkirch 67404, France.,Université de Strasbourg, Illkirch 67404, France
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20
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Salami CO, Jackson K, Jose C, Alyass L, Cisse GI, De BP, Stiles KM, Chiuchiolo MJ, Sondhi D, Crystal RG, Kaminsky SM. Stress-Induced Mouse Model of the Cardiac Manifestations of Friedreich's Ataxia Corrected by AAV-mediated Gene Therapy. Hum Gene Ther 2020; 31:819-827. [PMID: 32646255 DOI: 10.1089/hum.2019.363] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Friedreich's ataxia (FA), an autosomal recessive disorder caused by a deficiency in the expression of frataxin (FXN), is characterized by progressive ataxia and hypertrophic cardiomyopathy. Although cardiac dysfunction is the most common cause of mortality in FA, the cardiac disease remains subclinical for most of the clinical course because the neurologic disease limits muscle oxygen demands. Previous FXN knockout mouse models exhibit fatal cardiomyopathy similar to human FA, but in contrast to the human condition, untreated mice become moribund by 2 months of age, unlike humans where the cardiac disease often does not manifest until the third decade. The study was designed to create a mouse model for early FA disease relevant to the time for which a gene therapy would likely be most effective. To generate a cardiac-specific mouse model of FA cardiomyopathy similar to the human disease, we used a cardiac promoter (αMyhc) driving CRE recombinase cardiac-specific excision of FXN exon 4 to generate a mild, cardiac-specific FA model that is normal at rest, but exhibits the cardiac phenotype with stress. The hearts of αMyhc mice had decreased levels of FXN and activity of the mitochondrial complex II/complex IV respiratory chain. At rest, αMyhc mice exhibited normal cardiac function as assessed by echocardiographic assessment of ejection fraction and fractional shortening, but when the heart was stressed chemically with dobutamine, αMyhc mice compared with littermate control mice had a 62% reduction in the stress ejection fraction (p < 2 × 10-4) and 71% reduction in stress-related fractional shortening (p < 10-5). When assessing functional cardiac performance using running on an inclined treadmill, αMyhc mice stayed above the midline threefold less than littermate controls (p < 0.02). A one-time intravenous administration of 1011 genome copies of AAVrh.10hFXN, an adeno-associated virus (AAV) serotype rh10 gene transfer vector expressing human FXN, corrected the stress-induced ejection fraction and fractional shortening phenotypes. Treated αMyhc mice exhibited exercise performance on a treadmill indistinguishable from littermate controls (p > 0.07). These αMyhc mice provide an ideal model to study long-term cardiac complications due to FA and AAV-mediated gene therapy correction of stress-induced cardiac phenotypes typical of human FA.
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Affiliation(s)
- Christiana O Salami
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Katie Jackson
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Clarisse Jose
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Laith Alyass
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Georges-Ibrahim Cisse
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Bishnu P De
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Katie M Stiles
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Maria J Chiuchiolo
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Dolan Sondhi
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Stephen M Kaminsky
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
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21
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Outlining the Complex Pathway of Mammalian Fe-S Cluster Biogenesis. Trends Biochem Sci 2020; 45:411-426. [PMID: 32311335 DOI: 10.1016/j.tibs.2020.02.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/27/2020] [Accepted: 02/04/2020] [Indexed: 12/14/2022]
Abstract
Iron-sulfur (Fe-S) clusters (ISCs) are ubiquitous cofactors essential to numerous fundamental cellular processes. Assembly of ISCs and their insertion into apoproteins involves the function of complex cellular machineries that operate in parallel in the mitochondrial and cytosolic/nuclear compartments of mammalian cells. The spectrum of diseases caused by inherited defects in genes that encode the Fe-S assembly proteins has recently expanded to include multiple rare human diseases, which manifest distinctive combinations and severities of global and tissue-specific impairments. In this review, we provide an overview of our understanding of ISC biogenesis in mammalian cells, discuss recent work that has shed light on the molecular interactions that govern ISC assembly, and focus on human diseases caused by failures of the biogenesis pathway.
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22
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Vela D. Keeping heart homeostasis in check through the balance of iron metabolism. Acta Physiol (Oxf) 2020; 228:e13324. [PMID: 31162883 DOI: 10.1111/apha.13324] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 05/31/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023]
Abstract
Highly active cardiomyocytes need iron for their metabolic activity. In physiological conditions, iron turnover is a delicate process which is dependent on global iron supply and local autonomous regulatory mechanisms. Though less is known about the autonomous regulatory mechanisms, data suggest that these mechanisms can preserve cellular iron turnover even in the presence of systemic iron disturbance. Therefore, activity of local iron protein machinery and its relationship with global iron metabolism is important to understand cardiac iron metabolism in physiological conditions and in cardiac disease. Our knowledge in this respect has helped in designing therapeutic strategies for different cardiac diseases. This review is a synthesis of our current knowledge concerning the regulation of cardiac iron metabolism. In addition, different models of cardiac iron dysmetabolism will be discussed through the examples of heart failure (cardiomyocyte iron deficiency), myocardial infarction (acute changes in cardiac iron turnover), doxorubicin-induced cardiotoxicity (cardiomyocyte iron overload in mitochondria), thalassaemia (cardiomyocyte cytosolic and mitochondrial iron overload) and Friedreich ataxia (asymmetric cytosolic/mitochondrial cardiac iron dysmetabolism). Finally, future perspectives will be discussed in order to resolve actual gaps in knowledge, which should be helpful in finding new treatment possibilities in different cardiac diseases.
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Affiliation(s)
- Driton Vela
- Faculty of Medicine, Department of Physiology University of Prishtina Prishtina Kosovo
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23
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Gottesfeld JM. Molecular Mechanisms and Therapeutics for the GAA·TTC Expansion Disease Friedreich Ataxia. Neurotherapeutics 2019; 16:1032-1049. [PMID: 31317428 PMCID: PMC6985418 DOI: 10.1007/s13311-019-00764-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Friedreich ataxia (FRDA), the most common inherited ataxia, is caused by transcriptional silencing of the nuclear FXN gene, encoding the essential mitochondrial protein frataxin. Currently, there is no approved therapy for this fatal disorder. Gene silencing in FRDA is due to hyperexpansion of the triplet repeat sequence GAA·TTC in the first intron of the FXN gene, which results in chromatin histone modifications consistent with heterochromatin formation. Frataxin is involved in mitochondrial iron homeostasis and the assembly and transfer of iron-sulfur clusters to various mitochondrial enzymes and components of the electron transport chain. Frataxin insufficiency leads to progressive spinocerebellar neurodegeneration, causing symptoms of gait and limb ataxia, slurred speech, muscle weakness, sensory loss, and cardiomyopathy in many patients, resulting in death in early adulthood. Numerous approaches are being taken to find a treatment for FRDA, including excision or correction of the repeats by genome engineering methods, gene activation with small molecules or artificial transcription factors, delivery of frataxin to affected cells by protein replacement therapy, gene therapy, or small molecules to increase frataxin protein levels, and therapies aimed at countering the cellular consequences of reduced frataxin. This review will summarize the mechanisms involved in repeat-mediated gene silencing and recent efforts aimed at development of therapeutics.
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Affiliation(s)
- Joel M Gottesfeld
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, 92037, USA.
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