1
|
Edzeamey FJ, Ramchunder Z, Pourzand C, Anjomani Virmouni S. Emerging antioxidant therapies in Friedreich's ataxia. Front Pharmacol 2024; 15:1359618. [PMID: 38379897 PMCID: PMC10876797 DOI: 10.3389/fphar.2024.1359618] [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: 12/21/2023] [Accepted: 01/25/2024] [Indexed: 02/22/2024] Open
Abstract
Friedreich's ataxia (FRDA) is a rare childhood neurologic disorder, affecting 1 in 50,000 Caucasians. The disease is caused by the abnormal expansion of the GAA repeat sequence in intron 1 of the FXN gene, leading to the reduced expression of the mitochondrial protein frataxin. The disease is characterised by progressive neurodegeneration, hypertrophic cardiomyopathy, diabetes mellitus and musculoskeletal deformities. The reduced expression of frataxin has been suggested to result in the downregulation of endogenous antioxidant defence mechanisms and mitochondrial bioenergetics, and the increase in mitochondrial iron accumulation thereby leading to oxidative stress. The confirmation of oxidative stress as one of the pathological signatures of FRDA led to the search for antioxidants which can be used as therapeutic modality. Based on this observation, antioxidants with different mechanisms of action have been explored for FRDA therapy since the last two decades. In this review, we bring forth all antioxidants which have been investigated for FRDA therapy and have been signed off for clinical trials. We summarise their various target points in FRDA disease pathway, their performances during clinical trials and possible factors which might have accounted for their failure or otherwise during clinical trials. We also discuss the limitation of the studies completed and propose possible strategies for combinatorial therapy of antioxidants to generate synergistic effect in FRDA patients.
Collapse
Affiliation(s)
- Fred Jonathan Edzeamey
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, College of Health, Medicine, and Life Sciences (CHMLS), Brunel University London, Uxbridge, United Kingdom
| | - Zenouska Ramchunder
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, College of Health, Medicine, and Life Sciences (CHMLS), Brunel University London, Uxbridge, United Kingdom
| | - Charareh Pourzand
- Department of Life Sciences, University of Bath, Bath, United Kingdom
- Centre for Therapeutic Innovation, University of Bath, Bath, United Kingdom
| | - Sara Anjomani Virmouni
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, College of Health, Medicine, and Life Sciences (CHMLS), Brunel University London, Uxbridge, United Kingdom
| |
Collapse
|
2
|
Dionisi C, Chazalon M, Rai M, Keime C, Imbault V, Communi D, Puccio H, Schiffmann SN, Pandolfo M. Proprioceptors-enriched neuronal cultures from induced pluripotent stem cells from Friedreich ataxia patients show altered transcriptomic and proteomic profiles, abnormal neurite extension, and impaired electrophysiological properties. Brain Commun 2023; 5:fcad007. [PMID: 36865673 PMCID: PMC9972525 DOI: 10.1093/braincomms/fcad007] [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: 04/13/2022] [Revised: 09/28/2022] [Accepted: 01/14/2023] [Indexed: 01/19/2023] Open
Abstract
Friedreich ataxia is an autosomal recessive multisystem disorder with prominent neurological manifestations and cardiac involvement. The disease is caused by large GAA expansions in the first intron of the FXN gene, encoding the mitochondrial protein frataxin, resulting in downregulation of gene expression and reduced synthesis of frataxin. The selective loss of proprioceptive neurons is a hallmark of Friedreich ataxia, but the cause of the specific vulnerability of these cells is still unknown. We herein perform an in vitro characterization of human induced pluripotent stem cell-derived sensory neuronal cultures highly enriched for primary proprioceptive neurons. We employ neurons differentiated from healthy donors, Friedreich ataxia patients and Friedreich ataxia sibling isogenic control lines. The analysis of the transcriptomic and proteomic profile suggests an impairment of cytoskeleton organization at the growth cone, neurite extension and, at later stages of maturation, synaptic plasticity. Alterations in the spiking profile of tonic neurons are also observed at the electrophysiological analysis of mature neurons. Despite the reversal of the repressive epigenetic state at the FXN locus and the restoration of FXN expression, isogenic control neurons retain many features of Friedreich ataxia neurons. Our study suggests the existence of abnormalities affecting proprioceptors in Friedreich ataxia, particularly their ability to extend towards their targets and transmit proper synaptic signals. It also highlights the need for further investigations to better understand the mechanistic link between FXN silencing and proprioceptive degeneration in Friedreich ataxia.
Collapse
Affiliation(s)
| | | | - Myriam Rai
- Laboratory of Experimental Neurology, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Céline Keime
- Institut de Génétique et de Biologie Moléculaire et Cellulaire UMR 7104 CNRS-UdS / INSERM U1258, Université de Strasbourg, 67404 Illkirch Cedex, Strasbourg, France
| | - Virginie Imbault
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - David Communi
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Hélène Puccio
- Institut de Génétique et de Biologie Moléculaire et Cellulaire UMR 7104 CNRS-UdS / INSERM U1258, Université de Strasbourg, 67404 Illkirch Cedex, Strasbourg, France,Institut NeuroMyoGene (INMG) UMR5310—INSERM U1217, Faculté de Médecine, Université Claude Bernard—Lyon I, 69008 Lyon, France
| | - Serge N Schiffmann
- Laboratory of Neurophysiology, ULB-Neuroscience Institute (UNI), Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium
| | - Massimo Pandolfo
- Correspondence to: Massimo Pandolfo Department of Neurology and Neurosurgery McGill University, Montreal Neurological Institute 3801 University Street, Montreal, Quebec H3A 2B4, Canada E-mail:
| |
Collapse
|
3
|
Brown AF, Parkinson MH, Garcia-Moreno H, Mudanohwo E, Labrum R, Sweeney M, Giunti P. Friedreich's Ataxia Frequency in a Large Cohort of Genetically Undetermined Ataxia Patients. Front Neurol 2021; 12:736253. [PMID: 34956042 PMCID: PMC8697107 DOI: 10.3389/fneur.2021.736253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 10/19/2021] [Indexed: 11/25/2022] Open
Abstract
Background: Patients with suspected genetic ataxia are often tested for Friedreich's ataxia (FRDA) and/or a variety of spinocerebellar ataxias (SCAs). FRDA can present with atypical, late-onset forms and so may be missed in the diagnostic process. We aimed to determine FRDA-positive subjects among two cohorts of patients referred to a specialist ataxia centre either for FRDA or SCA testing to determine the proportion of FRDA cases missed in the diagnostic screening process. Methods: 2000 SCA-negative ataxia patients, not previously referred for FRDA testing (group A), were tested for FRDA expansions and mutations. This group was compared with 1768 ataxia patients who had been previously referred for FRDA testing (group B) and were therefore more likely to have a typical presentation. The phenotypes of positive cases were assessed through review of the clinical case notes. Results: Three patients (0.2%) in group A had the FRDA expansion on both alleles, compared with 207 patients (11.7%) in group B. The heterozygous carrier rate across both cohorts was of 41 out of 3,768 cases (1.1%). The size of the expansions in the three FRDA-positive cases in group A was small, and their presentation atypical with late-onset. Conclusions: This study demonstrates that FRDA is very rare among patients who were referred purely for SCA testing without the clinical suspicion of FRDA. Such cases should be referred to specialist ataxia centres for more extensive testing to improve patient management and outcomes.
Collapse
Affiliation(s)
- Alexander F. Brown
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - Michael H. Parkinson
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - Hector Garcia-Moreno
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| | - Ese Mudanohwo
- Neurogenetics Unit, National Hospital for Neurology & Neurosurgery, University College London Hospitals, Queen Square, London, United Kingdom
| | - Robyn Labrum
- Neurogenetics Unit, National Hospital for Neurology & Neurosurgery, University College London Hospitals, Queen Square, London, United Kingdom
| | - Mary Sweeney
- Neurogenetics Unit, National Hospital for Neurology & Neurosurgery, University College London Hospitals, Queen Square, London, United Kingdom
| | - Paola Giunti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, Queen Square, London, United Kingdom
| |
Collapse
|
4
|
Agrò M, Díaz-Nido J. Effect of Mitochondrial and Cytosolic FXN Isoform Expression on Mitochondrial Dynamics and Metabolism. Int J Mol Sci 2020; 21:E8251. [PMID: 33158039 PMCID: PMC7662637 DOI: 10.3390/ijms21218251] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/27/2020] [Accepted: 11/02/2020] [Indexed: 02/07/2023] Open
Abstract
Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by recessive mutations in the frataxin gene that lead to a deficiency of the mitochondrial frataxin (FXN) protein. Alternative forms of frataxin have been described, with different cellular localization and tissue distribution, including a cerebellum-specific cytosolic isoform called FXN II. Here, we explored the functional roles of FXN II in comparison to the mitochondrial FXN I isoform, highlighting the existence of potential cross-talk between cellular compartments. To achieve this, we transduced two human cell lines of patient and healthy subjects with lentiviral vectors overexpressing the mitochondrial or the cytosolic FXN isoforms and studied their effect on the mitochondrial network and metabolism. We confirmed the cytosolic localization of FXN isoform II in our in vitro models. Interestingly, both cytosolic and mitochondrial isoforms have an effect on mitochondrial dynamics, affecting different parameters. Accordingly, increases of mitochondrial respiration were detected after transduction with FXN I or FXN II in both cellular models. Together, these results point to the existence of a potential cross-talk mechanism between the cytosol and mitochondria, mediated by FXN isoforms. A more thorough knowledge of the mechanisms of action behind the extra-mitochondrial FXN II isoform could prove useful in unraveling FRDA physiopathology.
Collapse
Affiliation(s)
| | - Javier Díaz-Nido
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM) and Departamento de Biología Molecular, Universidad Autónoma de Madrid, Nicolás Cabrera, 1, 28049 Madrid, Spain;
| |
Collapse
|
5
|
Khristich AN, Mirkin SM. On the wrong DNA track: Molecular mechanisms of repeat-mediated genome instability. J Biol Chem 2020; 295:4134-4170. [PMID: 32060097 PMCID: PMC7105313 DOI: 10.1074/jbc.rev119.007678] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Expansions of simple tandem repeats are responsible for almost 50 human diseases, the majority of which are severe, degenerative, and not currently treatable or preventable. In this review, we first describe the molecular mechanisms of repeat-induced toxicity, which is the connecting link between repeat expansions and pathology. We then survey alternative DNA structures that are formed by expandable repeats and review the evidence that formation of these structures is at the core of repeat instability. Next, we describe the consequences of the presence of long structure-forming repeats at the molecular level: somatic and intergenerational instability, fragility, and repeat-induced mutagenesis. We discuss the reasons for gender bias in intergenerational repeat instability and the tissue specificity of somatic repeat instability. We also review the known pathways in which DNA replication, transcription, DNA repair, and chromatin state interact and thereby promote repeat instability. We then discuss possible reasons for the persistence of disease-causing DNA repeats in the genome. We describe evidence suggesting that these repeats are a payoff for the advantages of having abundant simple-sequence repeats for eukaryotic genome function and evolvability. Finally, we discuss two unresolved fundamental questions: (i) why does repeat behavior differ between model systems and human pedigrees, and (ii) can we use current knowledge on repeat instability mechanisms to cure repeat expansion diseases?
Collapse
Affiliation(s)
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, Massachusetts 02155.
| |
Collapse
|
6
|
Weng L, Wang Q, Yu S, Yang X, Lynch DR, Mesaros C, Blair IA. Evaluation of antibodies for western blot analysis of frataxin protein isoforms. J Immunol Methods 2019; 474:112629. [PMID: 31279523 PMCID: PMC6829029 DOI: 10.1016/j.jim.2019.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/21/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022]
Abstract
Frataxin is the protein that is down-regulated in Friedreich ataxia (FRDA), an autosomal recessive genetic disease caused by an intronic GAA repeat expansion in intron-1 of the FXN gene. The GAA repeats result in epigenetic silencing of the FXN gene and reduced expression of the cytosolic full-length frataxin (1-210) protein. Full length frataxin translocates to the mitochondria, leading to formation of mature frataxin (81-210) formed by cleavage of the mitochondrial targeting sequence at K-80 of the full-length protein. There are currently no approved treatments for FRDA, although experimental approaches involving up-regulation or replacement of mature frataxin protein through numerous approaches are being tested. Many of the pre-clinical studies of these experimental approaches are conducted in mouse and monkey models as well as in human cell lines. Consequently, well-validated antibodies are required for use in western blot analysis to determine whether levels of various forms of frataxin have been increased. Here we examined the specificity of five commercially available anti-frataxin antibodies and determined whether they detect mature frataxin in mouse heart tissue. Four protein standards of monkey, human, and mouse frataxin as well as mouse heart tissue were examined using polyacrylamide gel electrophoresis (PAGE) in combination with western blot analysis. One antibody failed to detect any of the frataxin standards or endogenous frataxin in mouse heart tissue. Three of the antibodies detected a protein in mouse heart tissue that ran slightly faster on PAGE (at 23.4 kDa) to that predicted for full-length frataxin (23.9 kDa). One antibody detected all four frataxin standards as well as endogenous mouse mature frataxin in mouse tissue. Significantly, this antibody, which will be useful for monitoring mature frataxin levels in monkey, human, and mouse tissues, did not detect a protein in mouse heart tissue at 23.4 kDa. Therefore, antibodies detecting the immunoreactive protein at 23.4 kDa could be misleading when testing for the up-regulation of frataxin in animal models.
Collapse
Affiliation(s)
- Liwei Weng
- Penn/CHOP Center of Excellence in Friedreich's Ataxia, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn SRP Center and Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Qingqing Wang
- Penn/CHOP Center of Excellence in Friedreich's Ataxia, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn SRP Center and Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sixiang Yu
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Xiaolu Yang
- Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David R Lynch
- Penn/CHOP Center of Excellence in Friedreich's Ataxia, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pediatrics and Neurology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Clementina Mesaros
- Penn/CHOP Center of Excellence in Friedreich's Ataxia, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn SRP Center and Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ian A Blair
- Penn/CHOP Center of Excellence in Friedreich's Ataxia, University of Pennsylvania, Philadelphia, PA 19104, USA; Penn SRP Center and Center of Excellence in Environmental Toxicology, Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| |
Collapse
|
7
|
Llorens JV, Soriano S, Calap-Quintana P, Gonzalez-Cabo P, Moltó MD. The Role of Iron in Friedreich's Ataxia: Insights From Studies in Human Tissues and Cellular and Animal Models. Front Neurosci 2019; 13:75. [PMID: 30833885 PMCID: PMC6387962 DOI: 10.3389/fnins.2019.00075] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/23/2019] [Indexed: 12/12/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a rare early-onset degenerative disease that affects both the central and peripheral nervous systems, and other extraneural tissues, mainly the heart and endocrine pancreas. This disorder progresses as a mixed sensory and cerebellar ataxia, primarily disturbing the proprioceptive pathways in the spinal cord, peripheral nerves and nuclei of the cerebellum. FRDA is an inherited disease with an autosomal recessive pattern caused by an insufficient amount of the nuclear-encoded mitochondrial protein frataxin, which is an essential and highly evolutionary conserved protein whose deficit results in iron metabolism dysregulation and mitochondrial dysfunction. The first experimental evidence connecting frataxin with iron homeostasis came from Saccharomyces cerevisiae; iron accumulates in the mitochondria of yeast with deletion of the frataxin ortholog gene. This finding was soon linked to previous observations of iron deposits in the hearts of FRDA patients and was later reported in animal models of the disease. Despite advances made in the understanding of FRDA pathophysiology, the role of iron in this disease has not yet been completely clarified. Some of the questions still unresolved include the molecular mechanisms responsible for the iron accumulation and iron-mediated toxicity. Here, we review the contribution of the cellular and animal models of FRDA and relevance of the studies using FRDA patient samples to gain knowledge about these issues. Mechanisms of mitochondrial iron overload are discussed considering the potential roles of frataxin in the major mitochondrial metabolic pathways that use iron. We also analyzed the effect of iron toxicity on neuronal degeneration in FRDA by reactive oxygen species (ROS)-dependent and ROS-independent mechanisms. Finally, therapeutic strategies based on the control of iron toxicity are considered.
Collapse
Affiliation(s)
- José Vicente Llorens
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Valencia, Spain
- Unit for Psychiatry and Neurodegenerative Diseases, Biomedical Research Institute INCLIVA, Valencia, Spain
| | - Sirena Soriano
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
| | - Pablo Calap-Quintana
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Valencia, Spain
- Unit for Psychiatry and Neurodegenerative Diseases, Biomedical Research Institute INCLIVA, Valencia, Spain
| | - Pilar Gonzalez-Cabo
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain
- Center of Biomedical Network Research on Rare Diseases CIBERER, Valencia, Spain
- Associated Unit for Rare Diseases INCLIVA-CIPF, Biomedical Research Institute INCLIVA, Valencia, Spain
| | - María Dolores Moltó
- Department of Genetics, Faculty of Biological Sciences, University of Valencia, Valencia, Spain
- Unit for Psychiatry and Neurodegenerative Diseases, Biomedical Research Institute INCLIVA, Valencia, Spain
- Center of Biomedical Network Research on Mental Health CIBERSAM, Valencia, Spain
| |
Collapse
|
8
|
Filatova EN, Utkin OV. The Role of Noncoding mRNA Isoforms in the Regulation of Gene Expression. RUSS J GENET+ 2018. [DOI: 10.1134/s1022795418080057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
9
|
Piguet F, de Montigny C, Vaucamps N, Reutenauer L, Eisenmann A, Puccio H. Rapid and Complete Reversal of Sensory Ataxia by Gene Therapy in a Novel Model of Friedreich Ataxia. Mol Ther 2018; 26:1940-1952. [PMID: 29853274 PMCID: PMC6094869 DOI: 10.1016/j.ymthe.2018.05.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/03/2018] [Accepted: 05/05/2018] [Indexed: 01/15/2023] Open
Abstract
Friedreich ataxia (FA) is a rare mitochondrial disease characterized by sensory and spinocerebellar ataxia, hypertrophic cardiomyopathy, and diabetes, for which there is no treatment. FA is caused by reduced levels of frataxin (FXN), an essential mitochondrial protein involved in the biosynthesis of iron-sulfur (Fe-S) clusters. Despite significant progress in recent years, to date, there are no good models to explore and test therapeutic approaches to stop or reverse the ganglionopathy and the sensory neuropathy associated to frataxin deficiency. Here, we report a new conditional mouse model with complete frataxin deletion in parvalbumin-positive cells that recapitulate the sensory ataxia and neuropathy associated to FA, albeit with a more rapid and severe course. Interestingly, although fully dysfunctional, proprioceptive neurons can survive for many weeks without frataxin. Furthermore, we demonstrate that post-symptomatic delivery of frataxin-expressing AAV allows for rapid and complete rescue of the sensory neuropathy associated with frataxin deficiency, thus establishing the pre-clinical proof of concept for the potential of gene therapy in treating FA neuropathy.
Collapse
Affiliation(s)
- Françoise Piguet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Charline de Montigny
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Nadège Vaucamps
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Laurence Reutenauer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Aurélie Eisenmann
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Hélène Puccio
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France.
| |
Collapse
|
10
|
Intron retention induced by microsatellite expansions as a disease biomarker. Proc Natl Acad Sci U S A 2018; 115:4234-4239. [PMID: 29610297 DOI: 10.1073/pnas.1716617115] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Expansions of simple sequence repeats, or microsatellites, have been linked to ∼30 neurological-neuromuscular diseases. While these expansions occur in coding and noncoding regions, microsatellite sequence and repeat length diversity is more prominent in introns with eight different trinucleotide to hexanucleotide repeats, causing hereditary diseases such as myotonic dystrophy type 2 (DM2), Fuchs endothelial corneal dystrophy (FECD), and C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). Here, we test the hypothesis that these GC-rich intronic microsatellite expansions selectively trigger host intron retention (IR). Using DM2, FECD, and C9-ALS/FTD as examples, we demonstrate that retention is readily detectable in affected tissues and peripheral blood lymphocytes and conclude that IR screening constitutes a rapid and inexpensive biomarker for intronic repeat expansion disease.
Collapse
|
11
|
Madireddy A, Gerhardt J. Replication Through Repetitive DNA Elements and Their Role in Human Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:549-581. [PMID: 29357073 DOI: 10.1007/978-981-10-6955-0_23] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human cells contain various repetitive DNA sequences, which can be a challenge for the DNA replication machinery to travel through and replicate correctly. Repetitive DNA sequence can adopt non-B DNA structures, which could block the DNA replication. Prolonged stalling of the replication fork at the endogenous repeats in human cells can have severe consequences such as genome instability that includes repeat expansions, contractions, and chromosome fragility. Several neurological and muscular diseases are caused by a repeat expansion. Furthermore genome instability is the major cause of cancer. This chapter describes some of the important classes of repetitive DNA sequences in the mammalian genome, their ability to form secondary DNA structures, their contribution to replication fork stalling, and models for repeat expansion as well as chromosomal fragility. Included in this chapter are also some of the strategies currently employed to detect changes in DNA replication and proteins that could prevent the repeat-mediated disruption of DNA replication in human cells. Additionally summarized are the consequences of repeat-associated perturbation of the DNA replication, which could lead to specific human diseases.
Collapse
|
12
|
Guaraldo M, Santambrogio P, Rovelli E, Di Savino A, Saglio G, Cittaro D, Roetto A, Levi S. Characterization of human mitochondrial ferritin promoter: identification of transcription factors and evidences of epigenetic control. Sci Rep 2016; 6:33432. [PMID: 27625068 PMCID: PMC5022048 DOI: 10.1038/srep33432] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 08/02/2016] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial ferritin (FtMt) is an iron storage protein belonging to the ferritin family but, unlike the cytosolic ferritin, it has an iron-unrelated restricted tissue expression. FtMt appears to be preferentially expressed in cell types characterized by high metabolic activity and oxygen consumption, suggesting a role in protecting mitochondria from iron-dependent oxidative damage. The human gene (FTMT) is intronless and its promoter region has not been described yet. To analyze the regulatory mechanisms controlling FTMT expression, we characterized the 5' flanking region upstream the transcriptional starting site of FTMT by in silico enquiry of sequences conservation, DNA deletion analysis, and ChIP assay. The data revealed a minimal promoter region and identified the presence of SP1, CREB and YY1 as positive regulators, and GATA2, FoxA1 and C/EBPβ as inhibitors of the transcriptional regulation. Furthermore, the FTMT transcription is increased by acetylating and de-methylating agent treatments in K562 and HeLa cells. These treatments up-regulate FtMt expression even in fibroblasts derived from a Friedreich ataxia patient, where it might exert a beneficial effect against mitochondrial oxidative damage. The expression of FTMT appears regulated by a complex mechanism involving epigenetic events and interplay between transcription factors.
Collapse
Affiliation(s)
- Michela Guaraldo
- San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milano, Italy
| | - Paolo Santambrogio
- San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milano, Italy
| | - Elisabetta Rovelli
- San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milano, Italy
| | - Augusta Di Savino
- University of Torino, Department of Clinical and Biological Sciences, AOU San Luigi Gonzaga, 10043 Orbassano, Torino, Italy
| | - Giuseppe Saglio
- University of Torino, Department of Clinical and Biological Sciences, AOU San Luigi Gonzaga, 10043 Orbassano, Torino, Italy
| | - Davide Cittaro
- San Raffaele Scientific Institute, Center for Translational Genomics and Bioinformatics, 20132 Milano, Italy
| | - Antonella Roetto
- University of Torino, Department of Clinical and Biological Sciences, AOU San Luigi Gonzaga, 10043 Orbassano, Torino, Italy
| | - Sonia Levi
- San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milano, Italy
- University Vita-Salute San Raffaele, 20132 Milano, Italy
| |
Collapse
|
13
|
Babaknejad N, Sayehmiri F, Sayehmiri K, Mohamadkhani A, Bahrami S. The Relationship between Zinc Levels and Autism: A Systematic Review and Meta-analysis. IRANIAN JOURNAL OF CHILD NEUROLOGY 2016; 10:1-9. [PMID: 27843460 PMCID: PMC5100031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/25/2015] [Accepted: 11/14/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Autism is a complex behaviorally defined disorder.There is a relationship between zinc (Zn) levels in autistic patients and development of pathogenesis, but the conclusion is not permanent. MATERIALS & METHODS The present study conducted to estimate this probability using meta-analysis method. In this study, Fixed Effect Model, twelve articles published from 1978 to 2012 were selected by searching Google scholar, PubMed, ISI Web of Science, and Scopus and information were analyzed. I² statistics were calculated to examine heterogeneity. The information was analyzed using R and STATA Ver. 12.2. RESULTS There was no significant statistical difference between hair, nail, and teeth Zn levels between controls and autistic patients: -0.471 [95% confidence interval (95% CI): -1.172 to 0.231]. There was significant statistical difference between plasma Zn concentration and autistic patients besides healthy controls: -0.253 (95% CI: 0.498 to -0.007). Using a Random Effect Model, the overall Integration of data from the two groups was -0.414 (95% CI: -0.878 to -0.051). CONCLUSION Based on sensitivity analysis, zinc supplements can be used for the nutritional therapy for autistic patients.
Collapse
Affiliation(s)
- Nasim Babaknejad
- Research Committee, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Fatemeh Sayehmiri
- Research Committee, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Kourosh Sayehmiri
- Department of Social Medicine, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran.; Department of Biostatistics, Research Center for Prevention of psychosocial impairment, University of Ilam, Ilam, Iran
| | - Ashraf Mohamadkhani
- Liver and Pancreatobiliary Diseases Research Center, Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Somaye Bahrami
- Research Committee, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| |
Collapse
|
14
|
Nageshwaran S, Festenstein R. Epigenetics and Triplet-Repeat Neurological Diseases. Front Neurol 2015; 6:262. [PMID: 26733936 PMCID: PMC4685448 DOI: 10.3389/fneur.2015.00262] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 11/30/2015] [Indexed: 01/15/2023] Open
Abstract
The term "junk DNA" has been reconsidered following the delineation of the functional significance of repetitive DNA regions. Typically associated with centromeres and telomeres, DNA repeats are found in nearly all organisms throughout their genomes. Repetitive regions are frequently heterochromatinized resulting in silencing of intrinsic and nearby genes. However, this is not a uniform rule, with several genes known to require such an environment to permit transcription. Repetitive regions frequently exist as dinucleotide, trinucleotide, and tetranucleotide repeats. The association between repetitive regions and disease was emphasized following the discovery of abnormal trinucleotide repeats underlying spinal and bulbar muscular atrophy (Kennedy's disease) and fragile X syndrome of mental retardation (FRAXA) in 1991. In this review, we provide a brief overview of epigenetic mechanisms and then focus on several diseases caused by DNA triplet-repeat expansions, which exhibit diverse epigenetic effects. It is clear that the emerging field of epigenetics is already generating novel potential therapeutic avenues for this group of largely incurable diseases.
Collapse
Affiliation(s)
- Sathiji Nageshwaran
- Division of Brain Sciences and MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus , London , UK
| | - Richard Festenstein
- Division of Brain Sciences and MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus , London , UK
| |
Collapse
|
15
|
GAA triplet-repeats cause nucleosome depletion in the human genome. Genomics 2015; 106:88-95. [DOI: 10.1016/j.ygeno.2015.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 06/15/2015] [Accepted: 06/18/2015] [Indexed: 11/18/2022]
|
16
|
Zeier Z, Esanov R, Belle KC, Volmar CH, Johnstone AL, Halley P, DeRosa BA, Khoury N, van Blitterswijk M, Rademakers R, Albert J, Brothers SP, Wuu J, Dykxhoorn DM, Benatar M, Wahlestedt C. Bromodomain inhibitors regulate the C9ORF72 locus in ALS. Exp Neurol 2015; 271:241-50. [PMID: 26099177 DOI: 10.1016/j.expneurol.2015.06.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 06/05/2015] [Accepted: 06/16/2015] [Indexed: 12/13/2022]
Abstract
A hexanucleotide repeat expansion residing within the C9ORF72 gene represents the most common known cause of amyotrophic lateral sclerosis (ALS) and places the disease among a growing family of repeat expansion disorders. The presence of RNA foci, repeat-associated translation products, and sequestration of RNA binding proteins suggests that toxic RNA gain-of-function contributes to pathology while C9ORF72 haploinsufficiency may be an additional pathological factor. One viable therapeutic strategy for treating expansion diseases is the use of small molecule inhibitors of epigenetic modifier proteins to reactivate expanded genetic loci. Indeed, previous studies have established proof of this principle by increasing the drug-induced expression of expanded (and abnormally heterochromatinized) FMR1, FXN and C9ORF72 genes in respective patient cells. While epigenetic modifier proteins are increasingly recognized as druggable targets, there have been few screening strategies to address this avenue of drug discovery in the context of expansion diseases. Here we utilize a semi-high-throughput gene expression based screen to identify siRNAs and small molecule inhibitors of epigenetic modifier proteins that regulate C9ORF72 RNA in patient fibroblasts, lymphocytes and reprogrammed motor neurons. We found that several bromodomain small molecule inhibitors increase the expression of C9ORF72 mRNA and pre-mRNA without affecting repressive epigenetic signatures of expanded C9ORF72 alleles. These data suggest that bromodomain inhibition increases the expression of unexpanded C9ORF72 alleles and may therefore compensate for haploinsufficiency without increasing the production of toxic RNA and protein products, thereby conferring therapeutic value.
Collapse
Affiliation(s)
- Zane Zeier
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Rustam Esanov
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Kinsley C Belle
- John P. Hussman Institute for Human Genomics and The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, USA
| | - Claude-Henry Volmar
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Andrea L Johnstone
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Paul Halley
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Brooke A DeRosa
- John P. Hussman Institute for Human Genomics and The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, USA
| | - Nathalie Khoury
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | | | | | | | - Shaun P Brothers
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Joanne Wuu
- Department of Neurology, University of Miami Miller School of Medicine, USA
| | - Derek M Dykxhoorn
- John P. Hussman Institute for Human Genomics and The Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, USA
| | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, USA
| | - Claes Wahlestedt
- Center for Therapeutic Innovation and Department of Psychiatry & Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| |
Collapse
|
17
|
Mastroeni D, Khdour OM, Arce PM, Hecht SM, Coleman PD. Novel antioxidants protect mitochondria from the effects of oligomeric amyloid beta and contribute to the maintenance of epigenome function. ACS Chem Neurosci 2015; 6:588-98. [PMID: 25668062 DOI: 10.1021/cn500323q] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Alzheimer's disease is associated with metabolic deficits and reduced mitochondrial function, with the latter due to the effects of oligomeric amyloid beta peptide (AβO) on the respiratory chain. Recent evidence has demonstrated reduction of epigenetic markers, such as DNA methylation, in Alzheimer's disease. Here we demonstrate a link between metabolic and epigenetic deficits via reduction of mitochondrial function which alters the expression of mediators of epigenetic modifications. AβO-induced loss of mitochondrial function in differentiated neuronal cells was reversed using two novel antioxidants (1 and 2); both have been shown to mitigate the effects of reactive oxygen species (ROS), and compound 1 also restores adenosine triphosphate (ATP) levels. While both compounds were effective in reducing ROS, restoration of ATP levels was associated with a more robust response to AβO treatment. Our in vitro system recapitulates key aspects of data from Alzheimer's brain samples, the expression of epigenetic genes in which are also shown to be normalized by the novel analogues.
Collapse
Affiliation(s)
- Diego Mastroeni
- L.J.
Roberts Alzheimer’s Disease Center, Banner Sun Health Research Institute, 10515 West Santa Fe Drive, Sun City, Arizona 85351, United States
- School
for Mental Health and Neuroscience (MHeNS), Department of Psychiatry
and Neuropsychology, Faculty of Health, Medicine and Life Sciences,
European Graduate School of Neuroscience (EURON), Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands
| | - Omar M. Khdour
- Center
for BioEnergetics, Biodesign Institute, and Department of Chemistry
and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Pablo M. Arce
- Center
for BioEnergetics, Biodesign Institute, and Department of Chemistry
and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Sidney M. Hecht
- Center
for BioEnergetics, Biodesign Institute, and Department of Chemistry
and Biochemistry, Arizona State University, Tempe, Arizona 85287, United States
| | - Paul D. Coleman
- L.J.
Roberts Alzheimer’s Disease Center, Banner Sun Health Research Institute, 10515 West Santa Fe Drive, Sun City, Arizona 85351, United States
| |
Collapse
|
18
|
Shah KA, McGinty RJ, Egorova VI, Mirkin SM. Coupling transcriptional state to large-scale repeat expansions in yeast. Cell Rep 2014; 9:1594-1602. [PMID: 25464841 DOI: 10.1016/j.celrep.2014.10.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 09/07/2014] [Accepted: 10/19/2014] [Indexed: 11/15/2022] Open
Abstract
Expansions of simple DNA repeats cause numerous hereditary disorders in humans. Replication, repair, and transcription are implicated in the expansion process, but their relative contributions are yet to be distinguished. To separate the roles of replication and transcription in the expansion of Friedreich's ataxia (GAA)n repeats, we designed two yeast genetic systems that utilize a galactose-inducible GAL1 promoter but contain these repeats in either the transcribed or nontranscribed region of a selectable cassette. We found that large-scale repeat expansions can occur in the lack of transcription. Induction of transcription strongly elevated the rate of expansions in both systems, indicating that active transcriptional state rather than transcription through the repeat per se affects this process. Furthermore, replication defects increased the rate of repeat expansions irrespective of transcriptional state. We present a model in which transcriptional state, linked to the nucleosomal density of a region, acts as a modulator of large-scale repeat expansions.
Collapse
Affiliation(s)
- Kartik A Shah
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Ryan J McGinty
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Vera I Egorova
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA.
| |
Collapse
|
19
|
Groh M, Lufino MMP, Wade-Martins R, Gromak N. R-loops associated with triplet repeat expansions promote gene silencing in Friedreich ataxia and fragile X syndrome. PLoS Genet 2014; 10:e1004318. [PMID: 24787137 PMCID: PMC4006715 DOI: 10.1371/journal.pgen.1004318] [Citation(s) in RCA: 246] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 03/06/2014] [Indexed: 12/14/2022] Open
Abstract
Friedreich ataxia (FRDA) and Fragile X syndrome (FXS) are among 40 diseases associated with expansion of repeated sequences (TREDs). Although their molecular pathology is not well understood, formation of repressive chromatin and unusual DNA structures over repeat regions were proposed to play a role. Our study now shows that RNA/DNA hybrids (R-loops) form in patient cells on expanded repeats of endogenous FXN and FMR1 genes, associated with FRDA and FXS. These transcription-dependent R-loops are stable, co-localise with repressive H3K9me2 chromatin mark and impede RNA Polymerase II transcription in patient cells. We investigated the interplay between repressive chromatin marks and R-loops on the FXN gene. We show that decrease in repressive H3K9me2 chromatin mark has no effect on R-loop levels. Importantly, increasing R-loop levels by treatment with DNA topoisomerase inhibitor camptothecin leads to up-regulation of repressive chromatin marks, resulting in FXN transcriptional silencing. This provides a direct molecular link between R-loops and the pathology of TREDs, suggesting that R-loops act as an initial trigger to promote FXN and FMR1 silencing. Thus R-loops represent a common feature of nucleotide expansion disorders and provide a new target for therapeutic interventions.
Collapse
Affiliation(s)
- Matthias Groh
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Michele M. P. Lufino
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Richard Wade-Martins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Natalia Gromak
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
20
|
Puccio H, Anheim M, Tranchant C. Pathophysiogical and therapeutic progress in Friedreich ataxia. Rev Neurol (Paris) 2014; 170:355-65. [PMID: 24792433 DOI: 10.1016/j.neurol.2014.03.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/25/2014] [Accepted: 03/26/2014] [Indexed: 01/10/2023]
Abstract
Friedreich ataxia (FRDA) is the most common hereditary autosomal recessive ataxia, but is also a multisystemic condition with frequent presence of cardiomyopathy or diabetes. It has been linked to expansion of a GAA-triplet repeat in the first intron of the FXN gene, leading to a reduced level of frataxin, a mitochondrial protein which, by controlling both iron entry and/or sulfide production, is essential to properly assemble and protect the Fe-S cluster during the initial stage of biogenesis. Several data emphasize the role of oxidative damage in FRDA, but better understanding of pathophysiological consequences of FXN mutations has led to develop animal models. Conditional knockout models recapitulate important features of the human disease but lack the genetic context, GAA repeat expansion-based knock-in and transgenic models carry a GAA repeat expansion but they only show a very mild phenotype. Cells derived from FRDA patients constitute the most relevant frataxin-deficient cell model as they carry the complete frataxin locus together with GAA repeat expansions and regulatory sequences. Induced pluripotent stem cell (iPSC)-derived neurons present a maturation delay and lower mitochondrial membrane potential, while cardiomyocytes exhibit progressive mitochondrial degeneration, with frequent dark mitochondria and proliferation/accumulation of normal mitochondria. Efforts in developing therapeutic strategies can be divided into three categories: iron chelators, antioxidants and/or stimulants of mitochondrial biogenesis, and frataxin level modifiers. A promising therapeutic strategy that is currently the subject of intense research is to directly target the heterochromatin state of the GAA repeat expansion with histone deacytelase inhibitors (HDACi) to restore frataxin levels.
Collapse
Affiliation(s)
- H Puccio
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Collège de France, chaire de génétique humaine, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France
| | - M Anheim
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Service de neurologie, unité des pathologies du mouvement, hôpital de Hautepierre, hôpital universitaire, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - C Tranchant
- Translational medicine and neurogenetics, institut de génétique et de biologie moléculaire et cellulaire (IGBMC), 1, rue Laurent-Fries, BP 10142, 67404 Illkirch cedex, France; Inserm, U596, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; CNRS, UMR7104, 1, rue Laurent-Fries, 67400 Illkirch Graffenstaden, France; Université de Strasbourg, 4, rue Blaise-Pascal, 67400 Strasbourg, France; Service de neurologie, unité des pathologies du mouvement, hôpital de Hautepierre, hôpital universitaire, 1, place de l'Hôpital, 67000 Strasbourg, France.
| |
Collapse
|
21
|
Eigentler A, Boesch S, Schneider R, Dechant G, Nat R. Induced pluripotent stem cells from friedreich ataxia patients fail to upregulate frataxin during in vitro differentiation to peripheral sensory neurons. Stem Cells Dev 2013; 22:3271-82. [PMID: 23879205 DOI: 10.1089/scd.2013.0126] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The value of human disease models, which are based on induced pluripotent stem cells (iPSCs), depends on the capacity to generate specifically those cell types affected by pathology. We describe a new iPSC-based model of Friedreich ataxia (FRDA), an autosomal recessive neurodegenerative disorder with an intronic GAA repeat expansion in the frataxin gene. As the peripheral sensory neurons are particularly susceptible to neurodegeneration in FRDA, we applied a development-based differentiation protocol to generate specifically these cells. FRDA and control iPSC lines were efficiently differentiated toward neural crest progenitors and peripheral sensory neurons. The progress of the cell lines through discrete steps of in vitro differentiation was closely monitored by expression levels of key markers for peripheral neural development. Since it had been suggested that FRDA pathology might start early during ontogenesis, we investigated frataxin expression in our development-related model. A pronounced frataxin deficit was found in FRDA iPSCs and neural crest cells compared to controls. Whereas we identified an upregulation of frataxin expression during sensory specification for control cells, this increase was not observed for FRDA peripheral sensory neurons. This early failure, aggravating frataxin deficiency in a specifically vulnerable human cell population, indicates a developmental component in FRDA.
Collapse
Affiliation(s)
- Andreas Eigentler
- 1 Department of Neurology, Innsbruck Medical University , Innsbruck, Austria
| | | | | | | | | |
Collapse
|
22
|
Abstract
Friedreich ataxia is the most common autosomal recessive ataxia. It is a progressive neurodegenerative disorder, typically with onset before 20 years of age. Signs and symptoms include progressive ataxia, ascending weakness and ascending loss of vibration and joint position senses, pes cavus, scoliosis, cardiomyopathy, and arrhythmias. There are no disease-modifying medications to either slow or halt the progression of the disease, but research investigating therapies to increase endogenous frataxin production and decrease the downstream consequences of disrupted iron homeostasis is ongoing. Clinical trials of promising medications are underway, and the treatment era of Friedreich ataxia is beginning.
Collapse
Affiliation(s)
- Abigail Collins
- Pediatrics and Neurology, Children's Hospital Colorado, University of Colorado, Denver, School of Medicine, 13123 East 16th Avenue, B155, Aurora, CO 80045, USA.
| |
Collapse
|
23
|
Perdomini M, Hick A, Puccio H, Pook MA. Animal and cellular models of Friedreich ataxia. J Neurochem 2013; 126 Suppl 1:65-79. [PMID: 23859342 DOI: 10.1111/jnc.12219] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/01/2013] [Accepted: 02/04/2013] [Indexed: 11/30/2022]
Abstract
The development and use of animal and cellular models of Friedreich ataxia (FRDA) are essential requirements for the understanding of FRDA disease mechanisms and the investigation of potential FRDA therapeutic strategies. Although animal and cellular models of lower organisms have provided valuable information on certain aspects of FRDA disease and therapy, it is intuitive that the most useful models are those of mammals and mammalian cells, which are the closest in physiological terms to FRDA patients. To date, there have been considerable efforts put into the development of several different FRDA mouse models and relevant FRDA mouse and human cell line systems. We summarize the principal mammalian FRDA models, discuss the pros and cons of each system, and describe the ways in which such models have been used to address two of the fundamental, as yet unanswered, questions regarding FRDA. Namely, what is the exact pathophysiology of FRDA and what is the detailed genetic and epigenetic basis of FRDA?
Collapse
Affiliation(s)
- Morgane Perdomini
- Translational Medecine and Neurogenetics, IGBMC-Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | | | | | | |
Collapse
|
24
|
Yandim C, Natisvili T, Festenstein R. Gene regulation and epigenetics in Friedreich's ataxia. J Neurochem 2013; 126 Suppl 1:21-42. [PMID: 23859339 DOI: 10.1111/jnc.12254] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/05/2013] [Accepted: 03/06/2013] [Indexed: 12/20/2022]
Abstract
This is an exciting time in the study of Friedreich's ataxia. Over the last 10 years much progress has been made in uncovering the mechanisms, whereby the Frataxin gene is silenced by (GAA)n repeat expansions and several of the findings are now ripe for testing in the clinic. The discovery that the Frataxin gene is heterochromatinised and that this can be antagonised in vivo has led to the tantalizing possibility that the disease might be amenable to a more radical therapeutic approach involving epigenetic modifiers. Here, we set out to review progress in the understanding of the fundamental mechanisms whereby genes are regulated at this level and how these findings have been applied to achieve a deeper understanding of the dysregulation that occurs as the primary genetic lesion in Friedreich's ataxia.
Collapse
Affiliation(s)
- Cihangir Yandim
- Gene Control Mechanisms and Disease, Department of Medicine and MRC Clinical Sciences Centre, Imperial College London, London, UK
| | | | | |
Collapse
|
25
|
Bayot A, Reichman S, Lebon S, Csaba Z, Aubry L, Sterkers G, Husson I, Rak M, Rustin P. Cis-silencing of PIP5K1B evidenced in Friedreich's ataxia patient cells results in cytoskeleton anomalies. Hum Mol Genet 2013; 22:2894-904. [PMID: 23552101 DOI: 10.1093/hmg/ddt144] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Friedreich's ataxia (FRDA) is a progressive neurodegenerative disease characterized by ataxia, variously associating heart disease, diabetes mellitus and/or glucose intolerance. It results from intronic expansion of GAA triplet repeats at the FXN locus. Homozygous expansions cause silencing of the FXN gene and subsequent decreased expression of the encoded mitochondrial frataxin. Detailed analyses in fibroblasts and neuronal tissues from FRDA patients have revealed profound cytoskeleton anomalies. So far, however, the molecular mechanism underlying these cytoskeleton defects remains unknown. We show here that gene silencing spreads in cis over the PIP5K1B gene in cells from FRDA patients (circulating lymphocytes and primary fibroblasts), correlating with expanded GAA repeat size. PIP5K1B encodes phosphatidylinositol 4-phosphate 5-kinase β type I (pip5k1β), an enzyme functionally linked to actin cytoskeleton dynamics that phosphorylates phosphatidylinositol 4-phosphate [PI(4)P] to generate phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. Accordingly, loss of pip5k1β function in FRDA cells was accompanied by decreased PI(4,5)P2 levels and was shown instrumental for destabilization of the actin network and delayed cell spreading. Knockdown of PIP5K1B in control fibroblasts using shRNA reproduced abnormal actin cytoskeleton remodeling, whereas over-expression of PIP5K1B, but not FXN, suppressed this phenotype in FRDA cells. In addition to provide new insights into the consequences of the FXN gene expansion, these findings raise the question whether PIP5K1B silencing may contribute to the variable manifestation of this complex disease.
Collapse
Affiliation(s)
- Aurélien Bayot
- Hôpital Robert Debré, INSERM UMR 676 Faculté de Médecine Denis Diderot, Université Paris 7, 75019 Paris, France.
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Xia H, Cao Y, Dai X, Marelja Z, Zhou D, Mo R, Al-Mahdawi S, Pook MA, Leimkühler S, Rouault TA, Li K. Novel frataxin isoforms may contribute to the pathological mechanism of Friedreich ataxia. PLoS One 2012; 7:e47847. [PMID: 23082224 PMCID: PMC3474739 DOI: 10.1371/journal.pone.0047847] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 09/21/2012] [Indexed: 12/12/2022] Open
Abstract
Friedreich ataxia (FRDA) is an inherited neurodegenerative disease caused by frataxin (FXN) deficiency. The nervous system and heart are the most severely affected tissues. However, highly mitochondria-dependent tissues, such as kidney and liver, are not obviously affected, although the abundance of FXN is normally high in these tissues. In this study we have revealed two novel FXN isoforms (II and III), which are specifically expressed in affected cerebellum and heart tissues, respectively, and are functional in vitro and in vivo. Increasing the abundance of the heart-specific isoform III significantly increased the mitochondrial aconitase activity, while over-expression of the cerebellum-specific isoform II protected against oxidative damage of Fe-S cluster-containing aconitase. Further, we observed that the protein level of isoform III decreased in FRDA patient heart, while the mRNA level of isoform II decreased more in FRDA patient cerebellum compared to total FXN mRNA. Our novel findings are highly relevant to understanding the mechanism of tissue-specific pathology in FRDA.
Collapse
Affiliation(s)
- Haiyan Xia
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
| | - Yun Cao
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Xiaoman Dai
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Zvonimir Marelja
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Di Zhou
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Ran Mo
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
| | - Sahar Al-Mahdawi
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Mark A. Pook
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom
| | - Silke Leimkühler
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Tracey A. Rouault
- Molecular Medicine Program, National Institute of Child Health and Human Development, Bethesda, Maryland, United States of America
| | - Kuanyu Li
- Jiangsu Key Laboratory of Molecular Medicine, Medical School of Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
| |
Collapse
|
27
|
Zhang Y, Shishkin AA, Nishida Y, Marcinkowski-Desmond D, Saini N, Volkov KV, Mirkin SM, Lobachev KS. Genome-wide screen identifies pathways that govern GAA/TTC repeat fragility and expansions in dividing and nondividing yeast cells. Mol Cell 2012; 48:254-65. [PMID: 22959270 DOI: 10.1016/j.molcel.2012.08.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 07/06/2012] [Accepted: 08/02/2012] [Indexed: 12/20/2022]
Abstract
Triplex structure-forming GAA/TTC repeats pose a dual threat to the eukaryotic genome integrity. Their potential to expand can lead to gene inactivation, the cause of Friedreich's ataxia disease in humans. In model systems, long GAA/TTC tracts also act as chromosomal fragile sites that can trigger gross chromosomal rearrangements. The mechanisms that regulate the metabolism of GAA/TTC repeats are poorly understood. We have developed an experimental system in the yeast Saccharomyces cerevisiae that allows us to systematically identify genes crucial for maintaining the repeat stability. Two major groups of mutants defective in DNA replication or transcription initiation are found to be prone to fragility and large-scale expansions. We demonstrate that problems imposed by the repeats during DNA replication in actively dividing cells and during transcription initiation in nondividing cells can culminate in genome instability. We propose that similar mechanisms can mediate detrimental metabolism of GAA/TTC tracts in human cells.
Collapse
Affiliation(s)
- Yu Zhang
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | | | | | | | | | | | | |
Collapse
|