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Tiberi J, Segatto M, Fiorenza MT, La Rosa P. Apparent Opportunities and Hidden Pitfalls: The Conflicting Results of Restoring NRF2-Regulated Redox Metabolism in Friedreich's Ataxia Pre-Clinical Models and Clinical Trials. Biomedicines 2023; 11:biomedicines11051293. [PMID: 37238963 DOI: 10.3390/biomedicines11051293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/18/2023] [Accepted: 04/22/2023] [Indexed: 05/28/2023] Open
Abstract
Friedreich's ataxia (FRDA) is an autosomal, recessive, inherited neurodegenerative disease caused by the loss of activity of the mitochondrial protein frataxin (FXN), which primarily affects dorsal root ganglia, cerebellum, and spinal cord neurons. The genetic defect consists of the trinucleotide GAA expansion in the first intron of FXN gene, which impedes its transcription. The resulting FXN deficiency perturbs iron homeostasis and metabolism, determining mitochondrial dysfunctions and leading to reduced ATP production, increased reactive oxygen species (ROS) formation, and lipid peroxidation. These alterations are exacerbated by the defective functionality of the nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor acting as a key mediator of the cellular redox signalling and antioxidant response. Because oxidative stress represents a major pathophysiological contributor to FRDA onset and progression, a great effort has been dedicated to the attempt to restore the NRF2 signalling axis. Despite this, the beneficial effects of antioxidant therapies in clinical trials only partly reflect the promising results obtained in preclinical studies conducted in cell cultures and animal models. For these reasons, in this critical review, we overview the outcomes obtained with the administration of various antioxidant compounds and critically analyse the aspects that may have contributed to the conflicting results of preclinical and clinical studies.
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Affiliation(s)
- Jessica Tiberi
- Division of Neuroscience, Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
- PhD Program in Behavioral Neuroscience, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
| | - Marco Segatto
- Department of Bioscience and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy
| | - Maria Teresa Fiorenza
- Division of Neuroscience, Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
- European Center for Brain Research, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00179 Rome, Italy
| | - Piergiorgio La Rosa
- Division of Neuroscience, Department of Psychology, Sapienza University of Rome, Via dei Marsi 78, 00185 Rome, Italy
- European Center for Brain Research, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 64, 00179 Rome, Italy
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2
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Seminotti B, Grings M, Tucci P, Leipnitz G, Saso L. Nuclear Factor Erythroid-2-Related Factor 2 Signaling in the Neuropathophysiology of Inherited Metabolic Disorders. Front Cell Neurosci 2021; 15:785057. [PMID: 34955754 PMCID: PMC8693715 DOI: 10.3389/fncel.2021.785057] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/05/2021] [Indexed: 01/14/2023] Open
Abstract
Inherited metabolic disorders (IMDs) are rare genetic conditions that affect multiple organs, predominantly the central nervous system. Since treatment for a large number of IMDs is limited, there is an urgent need to find novel therapeutical targets. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a transcription factor that has a key role in controlling the intracellular redox environment by regulating the expression of antioxidant enzymes and several important genes related to redox homeostasis. Considering that oxidative stress along with antioxidant system alterations is a mechanism involved in the neuropathophysiology of many IMDs, this review focuses on the current knowledge about Nrf2 signaling dysregulation observed in this group of disorders characterized by neurological dysfunction. We review here Nrf2 signaling alterations observed in X-linked adrenoleukodystrophy, glutaric acidemia type I, hyperhomocysteinemia, and Friedreich’s ataxia. Additionally, beneficial effects of different Nrf2 activators are shown, identifying a promising target for treatment of patients with these disorders. We expect that this article stimulates research into the investigation of Nrf2 pathway involvement in IMDs and the use of potential pharmacological modulators of this transcription factor to counteract oxidative stress and exert neuroprotection.
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Affiliation(s)
- Bianca Seminotti
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Mateus Grings
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Paolo Tucci
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Guilhian Leipnitz
- Postgraduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Department of Biochemistry, Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Postgraduate Program in Biological Sciences: Physiology, Institute of Basic Health Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Luciano Saso
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy
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Petrillo S, Santoro M, La Rosa P, Perna A, Gallo MG, Bertini ES, Silvestri G, Piemonte F. Nuclear Factor Erythroid 2-Related Factor 2 Activation Might Mitigate Clinical Symptoms in Friedreich's Ataxia: Clues of an "Out-Brain Origin" of the Disease From a Family Study. Front Neurosci 2021; 15:638810. [PMID: 33708070 PMCID: PMC7940825 DOI: 10.3389/fnins.2021.638810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/22/2021] [Indexed: 11/25/2022] Open
Abstract
Friedreich’s ataxia (FRDA) is the most frequent autosomal recessive ataxia in western countries, with a mean age of onset at 10–15 years. Patients manifest progressive cerebellar and sensory ataxia, dysarthria, lower limb pyramidal weakness, and other systemic manifestations. Previously, we described a family displaying two expanded GAA alleles not only in the proband affected by late-onset FRDA but also in the two asymptomatic family members: the mother and the younger sister. Both of them showed a significant reduction of frataxin levels, without any disease manifestation. Here, we analyzed if a protective mechanism might contribute to modulate the phenotype in this family. We particularly focused on the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2), the first line of antioxidant defense in cells, and on the glutathione (GSH) system, an index of reactive oxygen species (ROS) detoxification ability. Our findings show a great reactivity of the GSH system to the frataxin deficiency, particularly in the asymptomatic mother, where the genes of GSH synthesis [glutamate–cysteine ligase (GCL)] and GSSG detoxification [GSH S-reductase (GSR)] were highly responsive. The GSR was activated even in the asymptomatic sister and in the proband, reflecting the need of buffering the GSSG increase. Furthermore, and contrasting the NRF2 expression documented in FRDA tissues, NRF2 was highly activated in the mother and in the younger sister, while it was constitutively low in the proband. This suggests that, also under frataxin depletion, the endogenous stimulation of NRF2 in asymptomatic FRDA subjects may contribute to protect against the progressive oxidative damage, helping to prevent the onset of neurological symptoms and highlighting an “out-brain origin” of the disease.
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Affiliation(s)
- Sara Petrillo
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | | | - Piergiorgio La Rosa
- Division of Neuroscience, Department of Psychology, Sapienza University of Rome, Rome, Italy
| | - Alessia Perna
- Department of Neurosciences, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Maria Giovanna Gallo
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Enrico Silvio Bertini
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
| | - Gabriella Silvestri
- Department of Neurosciences, Università Cattolica del Sacro Cuore, Rome, Italy.,UOC of Neurology, Area of Neuroscience, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Fiorella Piemonte
- Unit of Muscular and Neurodegenerative Diseases, Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy
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Haberberger RV, Barry C, Dominguez N, Matusica D. Human Dorsal Root Ganglia. Front Cell Neurosci 2019; 13:271. [PMID: 31293388 PMCID: PMC6598622 DOI: 10.3389/fncel.2019.00271] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/04/2019] [Indexed: 12/14/2022] Open
Abstract
Sensory neurons with cell bodies situated in dorsal root ganglia convey information from external or internal sites of the body such as actual or potential harm, temperature or muscle length to the central nervous system. In recent years, large investigative efforts have worked toward an understanding of different types of DRG neurons at transcriptional, translational, and functional levels. These studies most commonly rely on data obtained from laboratory animals. Human DRG, however, have received far less investigative focus over the last 30 years. Nevertheless, knowledge about human sensory neurons is critical for a translational research approach and future therapeutic development. This review aims to summarize both historical and emerging information about the size and location of human DRG, and highlight advances in the understanding of the neurochemical characteristics of human DRG neurons, in particular nociceptive neurons.
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Affiliation(s)
- Rainer Viktor Haberberger
- Pain and Pulmonary Neurobiology Laboratory, Centre for Neuroscience, Anatomy and Histology, Flinders University, Adelaide, SA, Australia.,Órama Institute, Flinders University, Adelaide, SA, Australia
| | - Christine Barry
- Pain and Pulmonary Neurobiology Laboratory, Centre for Neuroscience, Anatomy and Histology, Flinders University, Adelaide, SA, Australia
| | - Nicholas Dominguez
- Pain and Pulmonary Neurobiology Laboratory, Centre for Neuroscience, Anatomy and Histology, Flinders University, Adelaide, SA, Australia
| | - Dusan Matusica
- Pain and Pulmonary Neurobiology Laboratory, Centre for Neuroscience, Anatomy and Histology, Flinders University, Adelaide, SA, Australia.,Órama Institute, Flinders University, Adelaide, SA, Australia
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Lynch DR, Hauser L, McCormick A, Wells M, Dong YN, McCormack S, Schadt K, Perlman S, Subramony SH, Mathews KD, Brocht A, Ball J, Perdok R, Grahn A, Vescio T, Sherman JW, Farmer JM. Randomized, double-blind, placebo-controlled study of interferon- γ 1b in Friedreich Ataxia. Ann Clin Transl Neurol 2019; 6:546-553. [PMID: 30911578 PMCID: PMC6414489 DOI: 10.1002/acn3.731] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 01/05/2019] [Accepted: 01/08/2019] [Indexed: 01/04/2023] Open
Abstract
Objective In vitro, in vivo, and open-label studies suggest that interferon gamma (IFN-γ 1b) may improve clinical features in Friedreich Ataxia through an increase in frataxin levels. The present study evaluates the efficacy and safety of IFN-γ 1b in the treatment of Friedreich Ataxia through a double-blind, multicenter, placebo-controlled trial. Methods Ninety-two subjects with FRDA between 10 and 25 years of age were enrolled. Subjects received either IFN-γ 1b or placebo for 6 months. The primary outcome measure was the modified Friedreich Ataxia Rating Scale (mFARS). Results No difference was noted between the groups after 6 months of treatment in the mFARS or secondary outcome measures. No change was noted in buccal cell or whole blood frataxin levels. However, during an open-label extension period, subjects had a more stable course than expected based on natural history data. Conclusions This study provides no direct evidence for a beneficial effect of IFN-γ1b in FRDA. The modest stabilization compared to natural history data leaves open the possibility that longer studies may demonstrate benefit.
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Affiliation(s)
- David R. Lynch
- Division of NeurologyChildren's Hospital of Philadelphia502 Abramson Research Center, 3615 Civic Center BlvdPhiladelphiaPennsylvania19104‐4318
| | - Lauren Hauser
- Division of NeurologyChildren's Hospital of Philadelphia502 Abramson Research Center, 3615 Civic Center BlvdPhiladelphiaPennsylvania19104‐4318
| | - Ashley McCormick
- Division of NeurologyChildren's Hospital of Philadelphia502 Abramson Research Center, 3615 Civic Center BlvdPhiladelphiaPennsylvania19104‐4318
| | - McKenzie Wells
- Division of NeurologyChildren's Hospital of Philadelphia502 Abramson Research Center, 3615 Civic Center BlvdPhiladelphiaPennsylvania19104‐4318
| | - Yi Na Dong
- Division of NeurologyChildren's Hospital of Philadelphia502 Abramson Research Center, 3615 Civic Center BlvdPhiladelphiaPennsylvania19104‐4318
| | - Shana McCormack
- Division of Endocrinology & DiabetesChildren's Hospital of PhiladelphiaPhiladelphia19104
| | - Kim Schadt
- Division of NeurologyChildren's Hospital of Philadelphia502 Abramson Research Center, 3615 Civic Center BlvdPhiladelphiaPennsylvania19104‐4318
| | - Susan Perlman
- Department of NeurologyUniversity of California Los AngelesBox 956975, 1‐167 RNRCLos AngelesCalifornia90095
| | - Sub H. Subramony
- Department of NeurologyUniversity of FloridaRoom L3‐100, McKnight Brain Institute, 1149 Newell DriveGainesvilleFlorida32611
| | - Katherine D. Mathews
- Department of Pediatrics and NeurologyUniversity of Iowa Carver College of MedicineIowa CityIowa
| | - Alicia Brocht
- Department of NeurologyUniversity of RochesterRochesterNew York14620
| | - Julie Ball
- Horizon Pharma, Inc.Lake ForestIllinois60045
| | | | - Amy Grahn
- Horizon Pharma, Inc.Lake ForestIllinois60045
| | - Tom Vescio
- Horizon Pharma, Inc.Lake ForestIllinois60045
| | | | - Jennifer M. Farmer
- Friedreich's Ataxia Research Alliance533 W Uwchlan AveDowningtownPennsylvania19335
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6
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Diagnostics and Treatments of Iron-Related CNS Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1173:179-194. [PMID: 31456211 DOI: 10.1007/978-981-13-9589-5_10] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Iron has been proposed to be responsible for neuronal loss in several diseases of the central nervous system, including Alzheimer's disease (AD), Parkinson's disease (PD), stroke, Friedreich's ataxia (FRDA), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS). In many diseases, abnormal accumulation of brain iron in disease-affected area has been observed, without clear knowledge of the contribution of iron overload to pathogenesis. Recent evidences implicate that key proteins involved in the disease pathogenesis may also participate in cellular iron metabolism, suggesting that the imbalance of brain iron homeostasis is associated with the diseases. Considering the complicated regulation of iron homeostasis within the brain, a thorough understanding of the molecular events leading to this phenotype is still to be investigated. However, current understanding has already provided the basis for the diagnosis and treatment of iron-related CNS diseases, which will be reviewed here.
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7
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Ferroptosis, a Recent Defined Form of Critical Cell Death in Neurological Disorders. J Mol Neurosci 2018; 66:197-206. [DOI: 10.1007/s12031-018-1155-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 08/06/2018] [Indexed: 12/12/2022]
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8
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Abstract
Trinucleotide repeat disorders comprise a variable group of inherited neurodegenerative diseases, with a large range in prevalence figures. There is a broad range in clinical presentations, but many of these diseases lead to some form of ataxia or other movement disorders, which are frequently combined with cognitive or psychiatric disturbances. This group can be divided into CAG- versus non-CAG-repeat diseases. Apart from spinocerebellar ataxia type 6 and 12 (SCA6 and SCA12), these CAG-repeat diseases, as well as Huntington disease-like 2 (HDL2) and SCA8, can be neuropathologically identified using 1C2 polyglutamine antibodies. In fragile X-associated tremor and ataxia, SCA6 and SCA12 ubiquitin/p62-positive and 1C2-negative inclusion bodies can be observed. In the other diseases proteinaceous inclusions are not found. For definite diagnosis genetic analysis is necessary.
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Affiliation(s)
- W F A Den Dunnen
- Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, The Netherlands.
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9
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Lin H, Magrane J, Clark EM, Halawani SM, Warren N, Rattelle A, Lynch DR. Early VGLUT1-specific parallel fiber synaptic deficits and dysregulated cerebellar circuit in the KIKO mouse model of Friedreich ataxia. Dis Model Mech 2017; 10:1529-1538. [PMID: 29259026 PMCID: PMC5769605 DOI: 10.1242/dmm.030049] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 10/30/2017] [Indexed: 01/01/2023] Open
Abstract
Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disorder with progressive ataxia that affects both the peripheral and central nervous system (CNS). While later CNS neuropathology involves loss of large principal neurons and glutamatergic and GABAergic synaptic terminals in the cerebellar dentate nucleus, early pathological changes in FRDA cerebellum remain largely uncharacterized. Here, we report early cerebellar VGLUT1 (SLC17A7)-specific parallel fiber (PF) synaptic deficits and dysregulated cerebellar circuit in the frataxin knock-in/knockout (KIKO) FRDA mouse model. At asymptomatic ages, VGLUT1 levels in cerebellar homogenates are significantly decreased, whereas VGLUT2 (SLC17A6) levels are significantly increased, in KIKO mice compared with age-matched controls. Additionally, GAD65 (GAD2) levels are significantly increased, while GAD67 (GAD1) levels remain unaltered. This suggests early VGLUT1-specific synaptic input deficits, and dysregulation of VGLUT2 and GAD65 synaptic inputs, in the cerebellum of asymptomatic KIKO mice. Immunohistochemistry and electron microscopy further show specific reductions of VGLUT1-containing PF presynaptic terminals in the cerebellar molecular layer, demonstrating PF synaptic input deficiency in asymptomatic and symptomatic KIKO mice. Moreover, the parvalbumin levels in cerebellar homogenates and Purkinje neurons are significantly reduced, but preserved in other interneurons of the cerebellar molecular layer, suggesting specific parvalbumin dysregulation in Purkinje neurons of these mice. Furthermore, a moderate loss of large principal neurons is observed in the dentate nucleus of asymptomatic KIKO mice, mimicking that of FRDA patients. Our findings thus identify early VGLUT1-specific PF synaptic input deficits and dysregulated cerebellar circuit as potential mediators of cerebellar dysfunction in KIKO mice, reflecting developmental features of FRDA in this mouse model.
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Affiliation(s)
- Hong Lin
- Departments of Pediatrics and Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jordi Magrane
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Elisia M Clark
- Departments of Pediatrics and Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarah M Halawani
- Departments of Pediatrics and Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nathan Warren
- Departments of Pediatrics and Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Amy Rattelle
- Departments of Pediatrics and Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - David R Lynch
- Departments of Pediatrics and Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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10
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Byard RW, Gilbert JD. Mechanisms of unexpected death and autopsy findings in Friedreich ataxia. MEDICINE, SCIENCE, AND THE LAW 2017; 57:192-196. [PMID: 28803513 DOI: 10.1177/0025802417723809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A 36-year-old woman with a clinical history of Friedreich ataxia and hypertrophic cardiomyopathy was found unexpectedly dead at her home. The heart showed asymmetric left ventricular hypertrophy, with an interventricular septal thickness of 20-25 mm (the remainder of the left ventricular wall measured 15 mm). Histologically, both ventricles had irregular areas of marked myocyte hypertrophy with associated interstitial fibrosis and focal myofibre disarray. There was neuronal loss within the dentate nucleus of the cerebellum, with vacuolation and axonal loss in the dorsal columns and spinocerebellar tracts of the upper cervical spinal cord. Death was due to hypertrophic cardiomyopathy complicating Friedreich ataxia. Other causes of death in this condition include embolic stroke, cerebral haemorrhage, aspiration pneumonia, renal failure, diabetic ketoacidosis, myocardial infarction, generalised inanition and trauma. Sudden death due to cardiac disease, resulting in presentation for medicolegal autopsy, may be the presenting feature at all ages, including childhood.
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Affiliation(s)
- Roger W Byard
- 1 The University of Adelaide Medical School, Australia
- 2 Forensic Science SA, Australia
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11
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Nonneurological Involvement in Late-Onset Friedreich Ataxia (LOFA): Exploring the Phenotypes. THE CEREBELLUM 2017; 16:253-256. [PMID: 26754264 DOI: 10.1007/s12311-015-0755-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Friedreich's ataxia (FDRA) is the most common inherited ataxia worldwide, caused by homozygous GAA expansions in the FXN gene. Patients usually have early onset ataxia, areflexia, Babinski sign, scoliosis and pes cavus, but at least 25 % of cases have atypical phenotypes. Disease begins after the age of 25 in occasional patients (late-onset Friedreich ataxia (LOFA)). Little is known about the frequency and clinical profile of LOFA patients. One hundred six patients with molecular confirmation of FDRA and followed in three Brazilian outpatient centers were enrolled. General demographics, GAA expansion size, age at onset, cardiac, endocrine, and skeletal manifestations were evaluated and compared between LOFA and classic FDRA (cFDRA) groups. We used Mann-Whitney and Fisher tests to compare means and proportions between groups; p values <0.05 were considered significant. LOFA accounted for 17 % (18/106) and cFDRA for 83 % (88/106) of the patients. There were 13 and 48 women in each group, respectively. LOFA patients were significantly older and had smaller GAA expansions. Clinically, LOFA group had a tendency toward lower frequency of diabetes/impaired glucose tolerance (5.8 vs. 17 %, p = 0.29) and cardiomyopathy (16.6 vs. 28.4 %, p = 0.38). Skeletal abnormalities were significantly less frequent in LOFA (scoliosis 22 vs. 61 %, p = 0.003, and pes cavus 22 vs.75 %, p < 0.001) as were spasticity and sustained reflexes, found in 22 % of LOFA patients but in none of the cFDRA patients (p = 0.001). LOFA accounts for 17 % of Brazilian FDRA patients evaluated herein. Clinically, orthopedic features and spasticity with retained reflexes are helpful tips to differentiate LOFA from cFDRA patients.
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Mollá B, Muñoz-Lasso DC, Riveiro F, Bolinches-Amorós A, Pallardó FV, Fernandez-Vilata A, de la Iglesia-Vaya M, Palau F, Gonzalez-Cabo P. Reversible Axonal Dystrophy by Calcium Modulation in Frataxin-Deficient Sensory Neurons of YG8R Mice. Front Mol Neurosci 2017; 10:264. [PMID: 28912677 PMCID: PMC5583981 DOI: 10.3389/fnmol.2017.00264] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/04/2017] [Indexed: 11/13/2022] Open
Abstract
Friedreich’s ataxia (FRDA) is a peripheral neuropathy involving a loss of proprioceptive sensory neurons. Studies of biopsies from patients suggest that axonal dysfunction precedes the death of proprioceptive neurons in a dying-back process. We observed that the deficiency of frataxin in sensory neurons of dorsal root ganglia (DRG) of the YG8R mouse model causes the formation of axonal spheroids which retain dysfunctional mitochondria, shows alterations in the cytoskeleton and it produces impairment of axonal transport and autophagic flux. The homogenous distribution of axonal spheroids along the neurites supports the existence of continues focal damages. This lead us to propose for FRDA a model of distal axonopathy based on axonal focal damages. In addition, we observed the involvement of oxidative stress and dyshomeostasis of calcium in axonal spheroid formation generating axonal injury as a primary cause of pathophysiology. Axonal spheroids may be a consequence of calcium imbalance, thus we propose the quenching or removal extracellular Ca2+ to prevent spheroids formation. In our neuronal model, treatments with BAPTA and o-phenanthroline reverted the axonal dystrophy and the mitochondrial dysmorphic parameters. These results support the hypothesis that axonal pathology is reversible in FRDA by pharmacological manipulation of intracellular Ca2+ with Ca2+ chelators or metalloprotease inhibitors, preventing Ca2+-mediated axonal injury. Thus, the modulation of Ca2+ levels may be a relevant therapeutic target to develop early axonal protection and prevent dying-back neurodegeneration.
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Affiliation(s)
- Belén Mollá
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Instituto de Biomedicina de Valencia (IBV), CSICValencia, Spain
| | - Diana C Muñoz-Lasso
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia-Instituto de Investigación Sanitaria (INCLIVA)Valencia, Spain.,Associated Unit for Rare Diseases INCLIVA-CIPFValencia, Spain.,VEDAS Corporación de Investigación e Innovación, VEDASCIIMedellín, Colombia
| | - Fátima Riveiro
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Fundacion Publica Galega de Medicina Xenomica (FPGMX)-SERGAS, Grupo de Medicina Xenomica, Hospital Clínico UniversitarioSantiago de Compostela, Spain
| | - Arantxa Bolinches-Amorós
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Cell Therapy Program, Prince Felipe Research Centre (CIPF)Valencia, Spain
| | - Federico V Pallardó
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia-Instituto de Investigación Sanitaria (INCLIVA)Valencia, Spain.,Associated Unit for Rare Diseases INCLIVA-CIPFValencia, Spain
| | | | - María de la Iglesia-Vaya
- Regional Ministry of Health in Valencia, Hospital Sagunto (CEIB-CSUSP)Valencia, Spain.,Brain Connectivity Laboratory, Joint Unit FISABIO & Prince Felipe Research Centre (CIPF)Valencia, Spain.,CIBER de Salud Mental (CIBERSAM)Valencia, Spain
| | - Francesc Palau
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Department of Genetic and Molecular Medicine, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de DéuBarcelona, Spain.,Department of Pediatrics, University of Barcelona School of MedicineBarcelona, Spain
| | - Pilar Gonzalez-Cabo
- CIBER de Enfermedades Raras (CIBERER)Valencia, Spain.,Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia-Instituto de Investigación Sanitaria (INCLIVA)Valencia, Spain.,Associated Unit for Rare Diseases INCLIVA-CIPFValencia, Spain
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13
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Koeppen AH, Becker AB, Qian J, Feustel PJ. Friedreich Ataxia: Hypoplasia of Spinal Cord and Dorsal Root Ganglia. J Neuropathol Exp Neurol 2017; 76:101-108. [PMID: 28082326 DOI: 10.1093/jnen/nlw111] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After Friedreich's description in 1877, depletion of myelinated fibers in the dorsal columns, dorsal spinocerebellar and lateral corticospinal tracts, and neuronal loss in the dorsal nuclei of Clarke columns were considered unique and essential neuropathological features of Friedreich ataxia (FA). Lack of large neurons in dorsal root ganglia (DRG), thinning of dorsal roots (DR), and poor myelination in sensory nerves are now recognized as key components of FA. Here, we measured cross-sectional areas of the mid-thoracic spinal cord (SC) and neuronal sizes in lumbosacral DRG of 24 genetically confirmed FA cases. Mean thoracic SC areas in FA (24.17 mm2) were significantly smaller than those in 12 normal controls (37.5 mm2); DRG neuron perikarya in FA (1362 µm2) were also significantly smaller than normal (2004 µm2). DRG neuron sizes were not correlated with SC areas. The FA patients included a wide range of disease onset and duration suggesting that the SC undergoes growth arrest early and remains abnormally small throughout life. Immunohistochemistry for phosphorylated neurofilament protein, peripheral myelin protein 22, and myelin proteolipid protein confirmed chaotic transition of axons into the SC in DR entry zones. We conclude that smaller SC areas and lack of large DRG neurons indicate hypoplasia rather than atrophy in FA.
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Affiliation(s)
- Arnulf H Koeppen
- Research Service, Veterans Affairs Medical Center, Albany, NY, USA.,Department of Pathology, Albany Medical College, Albany, NY, USA
| | - Alyssa B Becker
- Research Service, Veterans Affairs Medical Center, Albany, NY, USA
| | - Jiang Qian
- Department of Pathology, Albany Medical College, Albany, NY, USA
| | - Paul J Feustel
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, USA
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Mascalchi M, Bianchi A, Ciulli S, Ginestroni A, Aiello M, Dotti MT, Salvi F, Nicolai E, Soricelli A, Diciotti S. Lower medulla hypoplasia in Friedreich ataxia: MR Imaging confirmation 140 years later. J Neurol 2017. [PMID: 28620720 DOI: 10.1007/s00415-017-8542-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Mario Mascalchi
- Neuroscience Centre, "Anna Meyer" Children Hospital, Florence, Italy.
- "Mario Serio" Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.
| | - Andrea Bianchi
- "Mario Serio" Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Stefano Ciulli
- "Mario Serio" Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | | | | | - Maria Teresa Dotti
- Unit of Neurology and Neurometabolic Disorders, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Fabrizio Salvi
- "Il Bene" Center for Immunological and Rare Neurological Diseases at Bellaria Hospital, IRCCS, Istituto delle Scienze Neurologiche, Bologna, Italy
| | | | | | - Stefano Diciotti
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy
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15
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Rezende TJR, Martinez ARM, Faber I, Girotto K, Pedroso JL, Barsottini OG, Lopes-Cendes I, Cendes F, Faria AV, França MC. Structural signature of classical versus late-onset friedreich's ataxia by Multimodality brain MRI. Hum Brain Mapp 2017; 38:4157-4168. [PMID: 28543952 DOI: 10.1002/hbm.23655] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/08/2017] [Accepted: 05/11/2017] [Indexed: 01/08/2023] Open
Abstract
INTRODUCTION Friedreich's ataxia (FRDA) is the most common autosomal-recessive ataxia worldwide. It is characterized by early onset, sensory abnormalities, and slowly progressive ataxia. However, some individuals manifest the disease after the age of 25 years and are classified as late-onset FRDA (LOFA). Therefore, we propose a transversal multimodal MRI-based study to investigate which anatomical substrates are involved in classical (cFRDA) and LOFA. METHODS We enrolled 36 patients (13 with LOFA) and 29 healthy controls. All subjects underwent magnetic resonance imaging in a 3 T device; three-dimensional high-resolution T1-weighted images and diffusion tensor images were used to assess gray and white matter, respectively. We used T1 multiatlas approach to assess deep gray matter and cortical thickness measures to evaluate cerebral cortex and DTI multiatlas approach to assess white matter. All analyses were corrected for multiple comparisons. RESULTS Group comparison showed that both groups presented gray matter atrophy mostly in the motor cortex. Regarding white matter, we found abnormalities in the cerebellar peduncles, pyramidal tracts, midbrain, pons, and medulla oblongata for both groups, but the microstructural abnormalities in the cFRDA group were more widespread. In addition, we found that the corticospinal tract presented more severe microstructural damage in the LOFA group. Finally, the midbrain volume of the cFRDA, but not of the LOFA group, correlated with disease duration (R = -0.552, P = 0.012) and severity (R = -0.783, P < 0.001). CONCLUSION The cFRDA and LOFA groups have similar, but not identical neuroimaging damage pattern. These structural differences might help to explain the phenotypic variability observed in FRDA. Hum Brain Mapp 38:4157-4168, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Thiago Junqueira R Rezende
- Department of Neurology and Neuroimaging Laboratory, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
| | - Alberto Rolim M Martinez
- Department of Neurology and Neuroimaging Laboratory, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
| | - Ingrid Faber
- Department of Neurology and Neuroimaging Laboratory, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
| | - Karen Girotto
- Department of Neurology and Neuroimaging Laboratory, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
| | - José Luiz Pedroso
- Division of General Neurology and Ataxia Unit, Federal University of São Paulo, São Paulo, Sao Paulo, Brazil
| | - Orlando G Barsottini
- Division of General Neurology and Ataxia Unit, Federal University of São Paulo, São Paulo, Sao Paulo, Brazil
| | - Iscia Lopes-Cendes
- Department of Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
| | - Fernando Cendes
- Department of Neurology and Neuroimaging Laboratory, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
| | - Andreia V Faria
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Marcondes C França
- Department of Neurology and Neuroimaging Laboratory, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, Sao Paulo, Brazil
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Abeti R, Parkinson MH, Hargreaves IP, Angelova PR, Sandi C, Pook MA, Giunti P, Abramov AY. 'Mitochondrial energy imbalance and lipid peroxidation cause cell death in Friedreich's ataxia'. Cell Death Dis 2016; 7:e2237. [PMID: 27228352 PMCID: PMC4917650 DOI: 10.1038/cddis.2016.111] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/04/2016] [Accepted: 03/16/2016] [Indexed: 12/27/2022]
Abstract
Friedreich's ataxia (FRDA) is an inherited neurodegenerative disease. The mutation consists of a GAA repeat expansion within the FXN gene, which downregulates frataxin, leading to abnormal mitochondrial iron accumulation, which may in turn cause changes in mitochondrial function. Although, many studies of FRDA patients and mouse models have been conducted in the past two decades, the role of frataxin in mitochondrial pathophysiology remains elusive. Are the mitochondrial abnormalities only a side effect of the increased accumulation of reactive iron, generating oxidative stress? Or does the progressive lack of iron-sulphur clusters (ISCs), induced by reduced frataxin, cause an inhibition of the electron transport chain complexes (CI, II and III) leading to reactive oxygen species escaping from oxidative phosphorylation reactions? To answer these crucial questions, we have characterised the mitochondrial pathophysiology of a group of disease-relevant and readily accessible neurons, cerebellar granule cells, from a validated FRDA mouse model. By using live cell imaging and biochemical techniques we were able to demonstrate that mitochondria are deregulated in neurons from the YG8R FRDA mouse model, causing a decrease in mitochondrial membrane potential (▵Ψm) due to an inhibition of Complex I, which is partially compensated by an overactivation of Complex II. This complex activity imbalance leads to ROS generation in both mitochondrial matrix and cytosol, which results in glutathione depletion and increased lipid peroxidation. Preventing this increase in lipid peroxidation, in neurons, protects against in cell death. This work describes the pathophysiological properties of the mitochondria in neurons from a FRDA mouse model and shows that lipid peroxidation could be an important target for novel therapeutic strategies in FRDA, which still lacks a cure.
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Affiliation(s)
- R Abeti
- Ataxia Centre, Department of Molecular Neuroscience, UCL, Institute of Neurology, Queen Square, London, UK
| | - M H Parkinson
- Ataxia Centre, Department of Molecular Neuroscience, UCL, Institute of Neurology, Queen Square, London, UK
| | | | - P R Angelova
- Department of Molecular Neuroscience, UCL, Institute of Neurology, Queen Square, London, UK
| | - C Sandi
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, College of Health & Life Sciences, and Synthetic Biology Theme, Institute of Environment, Health & Societies, Brunel University London, Uxbridge, UK
| | - M A Pook
- Ataxia Research Group, Division of Biosciences, Department of Life Sciences, College of Health & Life Sciences, and Synthetic Biology Theme, Institute of Environment, Health & Societies, Brunel University London, Uxbridge, UK
| | - P Giunti
- Ataxia Centre, Department of Molecular Neuroscience, UCL, Institute of Neurology, Queen Square, London, UK
| | - A Y Abramov
- Department of Molecular Neuroscience, UCL, Institute of Neurology, Queen Square, London, UK
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Koeppen AH, Ramirez RL, Becker AB, Mazurkiewicz JE. Dorsal root ganglia in Friedreich ataxia: satellite cell proliferation and inflammation. Acta Neuropathol Commun 2016; 4:46. [PMID: 27142428 PMCID: PMC4855486 DOI: 10.1186/s40478-016-0288-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 02/13/2016] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION Dorsal root ganglia (DRG) are highly vulnerable to frataxin deficiency in Friedreich ataxia (FA), an autosomal recessive disease due to pathogenic homozygous guanine-adenine-adenine trinucleotide repeat expansions in intron 1 of the FXN gene (chromosome 9q21.11). An immunohistochemical and immunofluorescence study of DRG in 15 FA cases and 12 controls revealed that FA causes major primary changes in satellite cells and inflammatory destruction of neurons. A panel of antibodies was used to reveal the cytoplasm of satellite cells (glutamine synthetase, S100, metabotropic glutamate receptors 2/3, excitatory amino acid transporter 1, ATP-sensitive inward rectifier potassium channel 10, and cytosolic ferritin), gap junctions (connexin 43), basement membranes (laminin), mitochondria (ATP synthase subunit beta and frataxin), and monocytes (CD68 and IBA1). RESULTS Reaction product of the cytoplasmic markers and laminin confirmed proliferation of satellite cells and processes into multiple perineuronal layers and residual nodules. The formation of connexin 43-reactive gap junctions between satellite cells was strongly upregulated. Proliferating satellite cells in FA displayed many more frataxin- and ATP5B-reactive mitochondria than normal. Monocytes entered into the satellite cell layer, appeared to penetrate neuronal plasma membranes, and infiltrated residual nodules. Satellite cells and IBA1-reactive monocytes displayed upregulated ferritin biosynthesis, which was most likely due to leakage of iron from dying neurons. CONCLUSIONS We conclude that FA differentially affects the key cellular elements of DRG, and postulate that the disease causes loss of bidirectional trophic support between satellite cells and neurons.
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Affiliation(s)
- Arnulf H Koeppen
- Research Service, Veterans Affairs Medical Center, Albany, NY, USA.
- Departments of Neurology and Pathology, Albany Medical College, Albany, NY, USA.
| | - R Liane Ramirez
- Research Service, Veterans Affairs Medical Center, Albany, NY, USA
| | - Alyssa B Becker
- Research Service, Veterans Affairs Medical Center, Albany, NY, USA
| | - Joseph E Mazurkiewicz
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY, USA
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Harding IH, Corben LA, Storey E, Egan GF, Stagnitti MR, Poudel GR, Delatycki MB, Georgiou-Karistianis N. Fronto-cerebellar dysfunction and dysconnectivity underlying cognition in friedreich ataxia: The IMAGE-FRDA study. Hum Brain Mapp 2015; 37:338-50. [PMID: 26502936 DOI: 10.1002/hbm.23034] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 09/16/2015] [Accepted: 10/12/2015] [Indexed: 12/22/2022] Open
Abstract
Friedreich ataxia (FRDA) is a progressive neurodegenerative disorder defined by pathology within the cerebellum and spinal tracts. Although FRDA is most readily linked to motor and sensory dysfunctions, reported impairments in working memory and executive functions indicate that abnormalities may also extend to associations regions of the cerebral cortex and/or cerebello-cerebral interactions. To test this hypothesis, 29 individuals with genetically confirmed FRDA and 34 healthy controls performed a verbal n-back working memory task while undergoing functional magnetic resonance imaging. No significant group differences were evident in task performance. However, individuals with FRDA had deficits in brain activations both in the lateral cerebellar hemispheres, principally encompassing lobule VI, and the prefrontal cortex, including regions of the anterior insular and rostrolateral prefrontal cortices. Functional connectivity between these brain regions was also impaired, supporting a putative link between primary cerebellar dysfunction and subsequent cerebral abnormalities. Disease severity and genetic markers of disease liability were correlated specifically with cerebellar dysfunction, while correlations between behavioural performance and both cerebral activations and cerebello-cerebral connectivity were observed in controls, but not in the FRDA cohort. Taken together, these findings support a diaschisis model of brain dysfunction, whereby primary disease effects in the cerebellum result in functional changes in downstream fronto-cerebellar networks. These fronto-cerebellar disturbances provide a putative biological basis for the nonmotor symptoms observed in FRDA, and reflect the consequence of localized cerebellar pathology to distributed brain function underlying higher-order cognition.
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Affiliation(s)
- Ian H Harding
- School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Louise A Corben
- School of Psychological Sciences, Monash University, Melbourne, Australia.,Bruce Lefroy Centre, Murdoch Childrens Research Institute, Melbourne, Australia.,Friedreich Ataxia Clinic, Monash Medical Centre, Monash Health, Melbourne, Australia
| | - Elsdon Storey
- Department of Medicine, Monash University, Melbourne, Australia
| | - Gary F Egan
- Monash Biomedical Imaging, Monash University, Melbourne, Australia
| | | | - Govinda R Poudel
- School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Martin B Delatycki
- School of Psychological Sciences, Monash University, Melbourne, Australia.,Bruce Lefroy Centre, Murdoch Childrens Research Institute, Melbourne, Australia.,Department of Clinical Genetics, Austin Health, Melbourne, Australia
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Martínez-Sánchez P, Cazorla-García R, Sanz-Gallego I, Correas-Callero E, Pulido-Valdeolivas I, Arpa J. Substantia nigra echogenicity in hereditary ataxias with and without nigrostriatal pathology: a pilot study. THE CEREBELLUM 2015; 14:240-6. [PMID: 25592070 DOI: 10.1007/s12311-014-0642-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Our objective was to determine whether substantia nigra (SN) hyperechogenicity is greater in spinocerebellar ataxias (SCA) with nigrostriatal affectation than in ataxias without it. A cross-sectional case-control study analyzing four groups of patients was conducted: 1) nigrostriatal ataxias (SCA3 and SCA6), 2) nigrostriatal healthy controls matched by age and sex, 3) non-nigrostriatal ataxias (FRDA and SCA7), and 4) non-nigrostriatal healthy controls matched by age and sex. All the patients underwent a transcranial ultrasound performed by an experienced sonographer blinded to the clinical, genetic, and neuroimaging data. The SN area was measured and compared in the four groups. The SN area was also correlated with clinical features and genetic data in the two ataxia groups. We examined 12 patients with nigrostriatal ataxia (11 SCA3 and 1 SCA6), 12 nigrostriatal healthy control patients, 7 patients with non-nigrostriatal ataxia (5 FRDA and 2 SCA7), and 7 non-nigrostriatal healthy control patients. The median (IQR) SN area (cm(2)) was greater in the nigrostriatal ataxias compared with the controls (right SN, 0.43 [0.44] vs. 0.11 [0.25]; P=0.001; left SN, 0.32 [0.25] vs. 0.11 [0.16]; P=0.001), but was similar among the non-nigrostriatal ataxias and controls. There were no statistically significant differences in the SN area between the nigrostriatal and non-nigrostriatal ataxias, although there was a tendency for a greater left SN area in the nigrostriatal compared with the non-nigrostriatal ataxias (0.32 [0.25] vs. 0.16 [0.24], P=0.083). SN echogenicity is markedly greater in ataxias with nigrostriatal pathology than in controls. The role of SN hyperechogenicity in differentiating ataxias with and without nigrostriatal pathology should be elucidated in future studies.
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Affiliation(s)
- Patricia Martínez-Sánchez
- Department of Neurology and Stroke Center, La Paz University Hospital, Autonoma of Madrid University IdiPAZ Health Research Institute, Paseo de la Castellana 261, 28046, Madrid, Spain,
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Relevance of the glutathione system in temporal lobe epilepsy: evidence in human and experimental models. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:759293. [PMID: 25538816 PMCID: PMC4265701 DOI: 10.1155/2014/759293] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 11/11/2014] [Indexed: 12/14/2022]
Abstract
Oxidative stress, which is a state of imbalance in the production of reactive oxygen species and nitrogen, is induced by a wide variety of factors. This biochemical state is associated with diseases that are systemic as well as diseases that affect the central nervous system. Epilepsy is a chronic neurological disorder, and temporal lobe epilepsy represents an estimated 40% of all epilepsy cases. Currently, evidence from human and experimental models supports the involvement of oxidative stress during seizures and in the epileptogenesis process. Hence, the aim of this review was to provide information that facilitates the processing of this evidence and investigate the therapeutic impact of the biochemical status for this specific pathology.
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Laffita-Mesa JM, Bauer P. Herencia epigenética (metilación del ácido desoxirribonucleico): contexto clínico en neurodegeneraciones y gen ATXN2. Med Clin (Barc) 2014; 143:360-5. [DOI: 10.1016/j.medcli.2013.11.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/31/2013] [Accepted: 11/14/2013] [Indexed: 12/19/2022]
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Tajiri N, Staples M, Kaneko Y, Kim SU, Zesiewicz TA, Borlongan CV. Autologous stem cell transplant with gene therapy for Friedreich ataxia. Med Hypotheses 2014; 83:296-8. [PMID: 24962209 PMCID: PMC4145018 DOI: 10.1016/j.mehy.2014.05.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 05/23/2014] [Accepted: 05/28/2014] [Indexed: 11/25/2022]
Abstract
We advance the overarching hypothesis that stem cell therapy is a potent treatment for Friedreich's ataxia (FRDA). Here, we discuss the feasibility of autologous transplantation in FRDA, highlighting the need for the successful isolation of the FRDA patient's bone marrow-derived mesenchymal stem cells, followed by characterization that these cells maintain the GAA repeat expansion and the reduced FXN mRNA expression, both hallmark features of FRDA. Next, we discuss the need for assessment of the proliferative capability and pluripotency of FRDA patient's bone marrow-derived mesenchymal stem cells. In particular, we view the need for characterizing the in vitro differentiation of bone marrow-derived mesenchymal stem cells into the two cell types primarily affected in FRDA, peripheral neurons and cardiomyocytes. Finally, we discuss the need to test the application of bone marrow-derived mesenchymal stem cells as potent autologous donor cells for FRDA. The demonstration of the functional correction of the mutated gene in these cells will be a critical endpoint of determining the potential of stem cell therapy in FRDA. We envision a gene-based cell transplant strategy as a likely therapeutic approach for FRDA, involving stable insertion of functional human bacterial artificial chromosomes or BACs containing the intact FXN gene into stem cells, thereafter leading to the expression of frataxin protein in differentiated neurons/cardiomyocytes.
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Affiliation(s)
- Naoki Tajiri
- Center of Excellence for Aging & Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Meaghan Staples
- Center of Excellence for Aging & Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Yuji Kaneko
- Center of Excellence for Aging & Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Seung U Kim
- Department of Neurology, University of British Columbia, Vancouver, Canada
| | - Theresa A Zesiewicz
- University of South Florida Ataxia Research Center, Department of Neurology, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA
| | - Cesar V Borlongan
- Center of Excellence for Aging & Brain Repair, Department of Neurosurgery and Brain Repair, University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
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Myelin paucity of the superior cerebellar peduncle in individuals with Friedreich ataxia: an MRI magnetization transfer imaging study. J Neurol Sci 2014; 343:138-43. [PMID: 24930398 DOI: 10.1016/j.jns.2014.05.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 05/23/2014] [Accepted: 05/26/2014] [Indexed: 11/23/2022]
Abstract
The dentate nucleus (DN) is the major relay station for neural connection between the cerebellum and cerebrum via the thalamus, and is a significant component of the neuropathological profile of Friedreich ataxia (FRDA). We have previously shown that the size of the superior cerebellar peduncle (SCP), which links the DN to cortical and subcortical structures via the thalamus, is significantly reduced in individuals with FRDA compared to control participants. This study used magnetization transfer imaging (MTI) to examine and contrast the integrity of white matter (WM) in the SCP and the corpus callosum (CC) (control region) in ten individuals with FRDA and ten controls. Individuals with FRDA demonstrated a significant reduction in the magnetization transfer ratio (MTR) in the SCP compared to control participants. However, there was no significant difference between groups in MTR in the CC. When comparing regions within groups, there was a significant reduction in MTR in the SCP compared to CC in participants with FRDA only. We suggest that the reduction in MTR in the SCP may be indicative of lack of myelin secondary to axonal loss and oligodendroglial dysfunction in WM tracts in individuals with FRDA.
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Nieto A, Correia R, de Nóbrega E, Montón F, Barroso J. Cognition in late-onset Friedreich ataxia. THE CEREBELLUM 2014; 12:504-12. [PMID: 23397368 DOI: 10.1007/s12311-013-0457-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Friedreich ataxia (FRDA) is the most common hereditary ataxia. Since the discovery of the genetic cause of this disease, the phenotypic spectrum seems to be wider, including late-onset forms such as late-onset Friedreich ataxia--LOFA (25-39 years at onset). The neuropathological and clinical patterns in patients with LOFA are similar to those in patients with typical FRDA, but LOFA patients tend to have an overall milder, slowly evolving disease. Given the lack of data about cognitive performance of LOFA, we aimed to investigate whether differences in age at disease onset may be related also to differences at a cognitive level. Twenty-nine typical FRDA and seven LOFA patients were administered a comprehensive neuropsychological battery measuring multiple domains: processing speed, attention, working memory, executive functions, verbal and visual memory, visuoperceptive and visuospatial skills, visuoconstructive functions, and language. There were no significant differences in disease duration between the two groups of patients. Every patient group was matched in gender, age, years of education, and estimated IQ with a healthy-participant control group. Results indicate that both patient groups shared slowed motor processing speed and impaired conceptual thinking and verbal fluency. However, only typical FRDA patients showed a diminished cognitive processing speed and impaired visuoperceptive and visuoconstructive abilities. This pattern indicates that a later disease onset is associated to a milder cognitive impairment. Thus, our findings are in concordance with those related to clinical differences between typical FRDA and LOFA.
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Affiliation(s)
- Antonieta Nieto
- School of Psychology, University of La Laguna, 38205, La Laguna, Tenerife, Spain.
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Abstract
Abnormal accumulation of brain iron has been detected in various neurodegenerative diseases, but the contribution of iron overload to pathology remains unclear. In a group of distinctive brain iron overload diseases known as 'neurodegeneration with brain iron accumulation' (NBIA) diseases, nine disease genes have been identified. Brain iron accumulation is observed in the globus pallidus and other brain regions in NBIA diseases, which are often associated with severe dystonia and gait abnormalities. Only two of these diseases, aceruloplasminaemia and neuroferritinopathy, are directly caused by abnormalities in iron metabolism, mainly in astrocytes and neurons, respectively. Understanding the early molecular pathophysiology of these diseases should aid insights into the role of iron and the design of specific therapeutic approaches.
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Koeppen AH, Kuntzsch EC, Bjork ST, Ramirez RL, Mazurkiewicz JE, Feustel PJ. Friedreich ataxia: metal dysmetabolism in dorsal root ganglia. Acta Neuropathol Commun 2013; 1:26. [PMID: 24252376 PMCID: PMC3893523 DOI: 10.1186/2051-5960-1-26] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 06/16/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Friedreich ataxia (FA) causes distinctive lesions of dorsal root ganglia (DRG), including neuronal atrophy, satellite cell hyperplasia, and absorption of dying nerve cells into residual nodules. Two mechanisms may be involved: hypoplasia of DRG neurons from birth and superimposed iron (Fe)- and zinc (Zn)-mediated oxidative injury. This report presents a systematic analysis of DRG in 7 FA patients and 13 normal controls by X-ray fluorescence (XRF) of polyethylene glycol-embedded DRG; double-label confocal immunofluorescence microscopy of Zn- and Fe-related proteins; and immunohistochemistry of frataxin and the mitochondrial marker, ATP synthase F1 complex V β-polypeptide (ATP5B). RESULTS XRF revealed normal total Zn- and Fe-levels in the neural tissue of DRG in FA (mean ± standard deviation): Zn=5.46±2.29 μg/ml, Fe=19.99±13.26 μg/ml in FA; Zn=8.16±6.19 μg/ml, Fe=23.85±12.23 μg/ml in controls. Despite these unchanged total metal concentrations, Zn- and Fe-related proteins displayed major shifts in their cellular localization. The Zn transporter Zip14 that is normally expressed in DRG neurons and satellite cells became more prominent in hyperplastic satellite cells and residual nodules. Metallothionein 3 (MT3) stains confirmed reduction of neuronal size in FA, but MT3 expression remained low in hyperplastic satellite cells. In contrast, MT1/2 immunofluorescence was prominent in proliferating satellite cells. Neuronal ferritin immunofluorescence declined but remained strong in hyperplastic satellite cells and residual nodules. Satellite cells in FA showed a larger number of mitochondria expressing ATB5B. Frataxin immunohistochemistry in FA confirmed small neuronal sizes, irregular distribution of reaction product beneath the plasma membrane, and enhanced expression in hyperplastic satellite cells. CONCLUSIONS The pool of total cellular Zn in normal DRG equals 124.8 μM, which is much higher than needed for the proper function of Zn ion-dependent proteins. It is likely that any disturbance of Zn buffering by Zip14 and MT3 causes mitochondrial damage and cell death. In contrast to Zn, sequestration of Fe in hyperplastic satellite cells may represent a protective mechanism. The changes in the cellular localization of Zn- and Fe-handling proteins suggest metal transfer from degenerating DRG neurons to activated satellite cells and connect neuronal metal dysmetabolism with the pathogenesis of the DRG lesion in FA.
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Affiliation(s)
- Arnulf H Koeppen
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
- Neurology Service, Veterans Affairs Medical Center, Albany, NY 12208, USA
- Department of Neurology, Albany Medical College, Albany, NY 12208, USA
- Department of Pathology, Albany Medical College, Albany, NY 12208, USA
| | - Erik C Kuntzsch
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
| | - Sarah T Bjork
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
| | - R Liane Ramirez
- Research Services, Veterans Affairs Medical Center, 113 Holland Ave, Albany, NY 12208, USA
| | - Joseph E Mazurkiewicz
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
| | - Paul J Feustel
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208, USA
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Kelp A, Koeppen AH, Petrasch-Parwez E, Calaminus C, Bauer C, Portal E, Yu-Taeger L, Pichler B, Bauer P, Riess O, Nguyen HP. A novel transgenic rat model for spinocerebellar ataxia type 17 recapitulates neuropathological changes and supplies in vivo imaging biomarkers. J Neurosci 2013; 33:9068-81. [PMID: 23699518 PMCID: PMC6705027 DOI: 10.1523/jneurosci.5622-12.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/18/2013] [Accepted: 04/09/2013] [Indexed: 02/05/2023] Open
Abstract
Spinocerebellar ataxia 17 (SCA17) is an autosomal-dominant, late-onset neurodegenerative disorder caused by an expanded polyglutamine (polyQ) repeat in the TATA-box-binding protein (TBP). To further investigate this devastating disease, we sought to create a first transgenic rat model for SCA17 that carries a full human cDNA fragment of the TBP gene with 64 CAA/CAG repeats (TBPQ64). In line with previous observations in mouse models for SCA17, TBPQ64 rats show a severe neurological phenotype including ataxia, impairment of postural reflexes, and hyperactivity in early stages followed by reduced activity, loss of body weight, and early death. Neuropathologically, the severe phenotype of SCA17 rats was associated with neuronal loss, particularly in the cerebellum. Degeneration of Purkinje, basket, and stellate cells, changes in the morphology of the dendrites, nuclear TBP-positive immunoreactivity, and axonal torpedos were readily found by light and electron microscopy. While some of these changes are well recapitulated in existing mouse models for SCA17, we provide evidence that some crucial characteristics of SCA17 are better mirrored in TBPQ64 rats. Thus, this SCA17 model represents a valuable tool to pursue experimentation and therapeutic approaches that may be difficult or impossible to perform with SCA17 transgenic mice. We show for the first time positron emission tomography (PET) and diffusion tensor imaging (DTI) data of a SCA animal model that replicate recent PET studies in human SCA17 patients. Our results also confirm that DTI are potentially useful correlates of neuropathological changes in TBPQ64 rats and raise hope that DTI imaging could provide a biomarker for SCA17 patients.
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Affiliation(s)
- Alexandra Kelp
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Arnulf H. Koeppen
- Department of Neuropathology and Neurology, Albany, New York 12208, and
| | - Elisabeth Petrasch-Parwez
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, 44787 Bochum, Germany
| | - Carsten Calaminus
- Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, and
| | - Claudia Bauer
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Esteban Portal
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Libo Yu-Taeger
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Bernd Pichler
- Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, and
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Olaf Riess
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Huu Phuc Nguyen
- Institute of Medical Genetics and Applied Genomics
- Centre for Rare Diseases Tübingen, University of Tübingen, 72076 Tübingen, Germany
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Abstract
Friedreich ataxia is an autosomal recessive disorder that affects children and young adults. The mutation consists of a homozygous guanine-adenine-adenine trinucleotide repeat expansion that causes deficiency of frataxin, a small nuclear genome-encoded mitochondrial protein. Low frataxin levels lead to insufficient biosynthesis of iron-sulfur clusters that are required for mitochondrial electron transport and assembly of functional aconitase, and iron dysmetabolism of the entire cell. This review of the neuropathology of Friedreich ataxia stresses the critical role of hypoplasia and superimposed atrophy of dorsal root ganglia. Progressive destruction of dorsal root ganglia accounts for thinning of dorsal roots, degeneration of dorsal columns, transsynaptic atrophy of nerve cells in Clarke column and dorsal spinocerebellar fibers, atrophy of gracile and cuneate nuclei, and neuropathy of sensory nerves. The lesion of the dentate nucleus consists of progressive and selective atrophy of large glutamatergic neurons and grumose degeneration of corticonuclear synaptic terminals that contain γ-aminobutyric acid (GABA). Small GABA-ergic neurons and their projection fibers in the dentato-olivary tract survive. Atrophy of Betz cells and corticospinal tracts constitute a second intrinsic CNS lesion. In light of the selective vulnerability of organs and tissues to systemic frataxin deficiency, many questions about the pathogenesis of Friedreich ataxia remain.
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Affiliation(s)
- Arnulf H Koeppen
- Research Service, Veterans Affairs Medical Center, Albany, New York 12208, USA.
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Iron dysregulation in movement disorders. Neurobiol Dis 2012; 46:1-18. [DOI: 10.1016/j.nbd.2011.12.054] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/22/2011] [Accepted: 12/31/2011] [Indexed: 01/04/2023] Open
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Corben LA, Georgiou-Karistianis N, Bradshaw JL, Evans-Galea MV, Churchyard AJ, Delatycki MB. Characterising the neuropathology and neurobehavioural phenotype in Friedreich ataxia: a systematic review. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 769:169-84. [PMID: 23560311 DOI: 10.1007/978-1-4614-5434-2_11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Friedreich ataxia (FRDA), the most common of the hereditary ataxias, is an autosomal recessive, multisystem disorder characterised by progressive ataxia, sensory symptoms, weakness, scoliosis and cardiomyopathy. FRDA is caused by a GAA expansion in intron one of the FXN gene, leading to reduced levels of the encoded protein frataxin, which is thought to regulate cellular iron homeostasis. The cerebellar and spinocerebellar dysfunction seen in FRDA has known effects on motor function; however until recently slowed information processing has been the main feature consistently reported by the limited studies addressing cognitive function in FRDA. This chapter will systematically review the current literature regarding the neuropathological and neurobehavioural phenotype associated with FRDA. It will evaluate more recent evidence adopting systematic experimental methodologies that postulate that the neurobehavioural phenotype associated with FRDA is likely to involve impairment in cerebello-cortico connectivity.
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Affiliation(s)
- Louise A Corben
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, The Royal Children's Hospital, Parkville, Victoria, Australia.
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Schneider SA, Hardy J, Bhatia KP. Syndromes of neurodegeneration with brain iron accumulation (NBIA): An update on clinical presentations, histological and genetic underpinnings, and treatment considerations. Mov Disord 2011; 27:42-53. [DOI: 10.1002/mds.23971] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 08/09/2011] [Accepted: 08/15/2011] [Indexed: 11/07/2022] Open
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The cerebellar component of Friedreich's ataxia. Acta Neuropathol 2011; 122:323-30. [PMID: 21638087 DOI: 10.1007/s00401-011-0844-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 05/24/2011] [Accepted: 05/24/2011] [Indexed: 10/18/2022]
Abstract
Lack of frataxin in Friedreich's ataxia (FRDA) causes a complex neurological and pathological phenotype. Progressive atrophy of the dentate nucleus (DN) is a major intrinsic central nervous system lesion. Antibodies to neuron-specific enolase (NSE), calbindin, glutamic acid decarboxylase (GAD), and vesicular glutamate transporters 1 and 2 (VGluT1, VGluT2) allowed insight into the disturbed synaptic circuitry of the DN. The available case material included autopsy specimens of 24 patients with genetically defined FRDA and 14 normal controls. In FRDA, the cerebellar cortex revealed intact Purkinje cell somata and dendrites as assessed by calbindin immunoreactivity. The DN, however, displayed severe loss of large NSE-reactive neurons. Small neurons remained intact. Labeling of Purkinje cells, basket fibers, Golgi neurons, and Golgi axonal plexuses with antibodies to GAD indicated normal intrinsic circuitry of the cerebellar cortex involving γ-aminobutyric acid (GABA). In contrast, the DN displayed severe loss of GABA-ergic terminals and formation of GAD- and calbindin-reactive grumose degeneration. The surviving small GAD-positive DN neurons provided normal GABA-ergic terminals to intact inferior olivary nuclei. The olives also received normal glutamatergic terminals as shown by VGluT2-reactivity. VGluT1-immunocytochemistry of the cerebellar cortex confirmed normal glutamatergic input to the molecular layer by parallel fibers and the granular layer by mossy fibers. VGluT2-immunoreactivity visualized normal climbing fibers and mossy fiber terminals. The DN, however, showed depletion of VGluT1- and VGluT2-reactive terminals arising from climbing and mossy fiber collaterals. The main functional deficit underlying cerebellar ataxia in FRDA is defective processing of inhibitory and excitatory impulses that converge on the large neurons of the DN. The reason for the selective vulnerability of these nerve cells remains elusive.
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Koeppen AH. Friedreich's ataxia: pathology, pathogenesis, and molecular genetics. J Neurol Sci 2011; 303:1-12. [PMID: 21315377 PMCID: PMC3062632 DOI: 10.1016/j.jns.2011.01.010] [Citation(s) in RCA: 303] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 12/29/2010] [Accepted: 01/12/2011] [Indexed: 12/27/2022]
Abstract
The pathogenic mutation in Friedreich's ataxia (FRDA) is a homozygous guanine-adenine-adenine (GAA) trinucleotide repeat expansion on chromosome 9q13 that causes a transcriptional defect of the frataxin gene. Deficiency of frataxin, a small mitochondrial protein, is responsible for all clinical and morphological manifestations of FRDA. This autosomal recessive disease affects central and peripheral nervous systems, heart, skeleton, and endocrine pancreas. Long expansions lead to early onset, severe clinical illness, and death in young adult life. Patients with short expansions have a later onset and a more benign course. Some are not diagnosed during life. The neurological phenotype reflects lesions in dorsal root ganglia (DRG), sensory peripheral nerves, corticospinal tracts, and dentate nuclei (DN). Most patients succumb to cardiomyopathy, and many become diabetic during the course of their disease. This review seeks to reconcile the diverse clinical features with pathological and molecular data. In the pathogenesis of the lesion in DRG, dorsal spinal roots, and sensory peripheral nerves, developmental defects and atrophy occur in combination. The progressive lesion of the DN lacks a known developmental component. Destruction of the DN, optic atrophy, and degeneration of the corticospinal tracts are intrinsic central nervous system lesions. Fiber loss in dorsal columns and spinocerebellar tracts, and atrophy of the neurons in the dorsal nuclei of Clarke are secondary to the lesion in DRG. The role of frataxin deficiency in the pathogenesis of FRDA is still unclear because the protein has multiple functions in the normal state, including biogenesis of iron-sulfur clusters; iron chaperoning; iron storage; and control of iron-mediated oxidative tissue damage.
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Affiliation(s)
- Arnulf H Koeppen
- VA Medical Center, 113 Holland Ave, and Albany Medical College, 47 New Scotland Ave, Albany, NY 12208, USA.
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