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Wen X, Xu H, Woolley PR, Conway OM, Yao J, Matouschek A, Lambowitz AM, Paull TT. Senataxin deficiency disrupts proteostasis through nucleolar ncRNA-driven protein aggregation. J Cell Biol 2024; 223:e202309036. [PMID: 38717338 PMCID: PMC11080644 DOI: 10.1083/jcb.202309036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 01/19/2024] [Accepted: 03/13/2024] [Indexed: 05/12/2024] Open
Abstract
Senataxin is an evolutionarily conserved RNA-DNA helicase involved in DNA repair and transcription termination that is associated with human neurodegenerative disorders. Here, we investigated whether Senataxin loss affects protein homeostasis based on previous work showing R-loop-driven accumulation of DNA damage and protein aggregates in human cells. We find that Senataxin loss results in the accumulation of insoluble proteins, including many factors known to be prone to aggregation in neurodegenerative disorders. These aggregates are located primarily in the nucleolus and are promoted by upregulation of non-coding RNAs expressed from the intergenic spacer region of ribosomal DNA. We also map sites of R-loop accumulation in human cells lacking Senataxin and find higher RNA-DNA hybrids within the ribosomal DNA, peri-centromeric regions, and other intergenic sites but not at annotated protein-coding genes. These findings indicate that Senataxin loss affects the solubility of the proteome through the regulation of transcription-dependent lesions in the nucleus and the nucleolus.
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Affiliation(s)
- Xuemei Wen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Hengyi Xu
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Phillip R. Woolley
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Olivia M. Conway
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Jun Yao
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Andreas Matouschek
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Alan M. Lambowitz
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Tanya T. Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
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2
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Westover KR, Jin P, Yao B. Bridging the gap: R-loop mediated genomic instability and its implications in neurological diseases. Epigenomics 2024; 16:589-608. [PMID: 38530068 PMCID: PMC11160457 DOI: 10.2217/epi-2023-0379] [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: 10/27/2023] [Accepted: 03/12/2024] [Indexed: 03/27/2024] Open
Abstract
R-loops, intricate three-stranded structures formed by RNA-DNA hybrids and an exposed non-template DNA strand, are fundamental to various biological phenomena. They carry out essential and contrasting functions within cellular mechanisms, underlining their critical role in maintaining cellular homeostasis. The specific cellular context that dictates R-loop formation determines their function, particularly emphasizing the necessity for their meticulous genomic regulation. Notably, the aberrant formation or misregulation of R-loops is implicated in numerous neurological disorders. This review focuses on the complex interactions between R-loops and double-strand DNA breaks, exploring how R-loop dysregulation potentially contributes to the pathogenesis of various brain disorders, which could provide novel insights into the molecular mechanisms underpinning neurological disease progression and identify potential therapeutic targets by highlighting these aspects.
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Affiliation(s)
- Katherine R Westover
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
| | - Bing Yao
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
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3
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Jeridi C, Rachdi A, Nabli F, Saied Z, Zouari R, Ben Mohamed D, Ben Said M, Masmoudi S, Ben Sassi S, Amouri R. Genetic heterogeneity within a consanguineous family involving TTPA and SETX genes. J Neurogenet 2023; 37:124-130. [PMID: 38109176 DOI: 10.1080/01677063.2023.2281916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 11/03/2023] [Indexed: 12/19/2023]
Abstract
Autosomal recessive cerebellar ataxias (ARCA) constitute a highly heterogeneous group of progressive neurodegenerative disorders that typically occur prior to adulthood. Despite some clinical resemblance between these disorders, different genes are involved. We report in this study four Tunisian patients belonging to the same large consanguineous family, sharing autosomal recessive cerebellar ataxia phenotypes but with clinical, biological, electrophysiological, and radiological differences leading to the diagnosis of two distinct ARCA caused by two distinct gene defects. Two of our patients presented ataxia with the vitamin E deficiency (AVED) phenotype, and the other two presented ataxia with oculo-motor apraxia 2 (AOA2). Genetic testing confirmed the clinical diagnosis by the detection of a frameshift c.744delA pathogenic variant in the TTPA gene, which is the most frequent in Tunisia, and a new variant c.1075dupT in the SETX gene. In Tunisia, data suggest that genetic disorders are common. The combined effects of the founder effect and inbreeding, added to genetic drift, may increase the frequency of detrimental rare disorders. The genetic heterogeneity observed in this family highlights the difficulty of genetic counseling in an inbred population. The examination and genetic testing of all affected patients, not just the index patient, is essential to not miss a treatable ataxia such as AVED, as in the case of this family.
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Affiliation(s)
- Cyrine Jeridi
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Amine Rachdi
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Fatma Nabli
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Zacharia Saied
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Rania Zouari
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Dina Ben Mohamed
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Mariem Ben Said
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisia
| | - Samia Ben Sassi
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Rim Amouri
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
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4
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Ponger P, Kurolap A, Lerer I, Dagan J, Chai Gadot C, Mory A, Wilnai Y, Oniashvili N, Giladi N, Gurevich T, Meiner V, Lossos A, Baris Feldman H. Unique Ataxia-Oculomotor Apraxia 2 (AOA2) in Israel with Novel Variants, Atypical Late Presentation, and Possible Identification of a Poison Exon. J Mol Neurosci 2022; 72:1715-1723. [PMID: 35676594 DOI: 10.1007/s12031-022-02035-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/27/2022] [Indexed: 10/18/2022]
Abstract
AOA2 is a rare progressive adolescent-onset disease characterised by cerebellar vermis atrophy, peripheral neuropathy and elevated serum alpha-fetoprotein (AFP) caused by pathogenic bi-allelic variants in SETX, encoding senataxin, involved in DNA repair and RNA maturation. Sanger sequencing of genomic DNA, co-segregation and oxidative stress functional studies were performed in Family 1. Trio whole-exome sequencing (WES), followed by SETX RNA and qRT-PCR analysis, were performed in Family 2. Sanger sequencing in Family 1 revealed two novel in-frame SETX deletion and duplication variants in trans (c.7009_7011del; p.Val2337del and c.7369_7371dup; p.His2457dup). Patients had increased induced chromosomal aberrations at baseline and following exposure to higher mitomycin-C concentration and increased sensitivity to oxidative stress at the lower mitomycin-C concentration in cell viability test. Trio WES in Family 2 revealed two novel SETX variants in trans, a nonsense variant (c.568C > T; p.Gln190*), and a deep intronic variant (c.5549-107A > G). Intronic variant analysis and SETX mRNA expression revealed activation of a cryptic exon introducing a premature stop codon (p.Met1850Lysfs*18) and resulting in aberrant splicing, as shown by qRT-PCR analysis, thus leading to higher levels of cryptic exon activation. Along with a second deleterious allele, this variant leads to low levels of SETX mRNA and disease manifestations. Our report expands the phenotypic spectrum of AOA2. Results provide initial support for the hypomorphic nature of the novel in-frame deletion and duplication variants in Family 1. Deep-intronic variant analysis of Family 2 variants potentially reveals a previously undescribed poison exon in the SETX gene, which may contribute to tailored therapy development.
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Affiliation(s)
- Penina Ponger
- Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel. .,The Genetics Institute and Genomics Center, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.
| | - Alina Kurolap
- The Genetics Institute and Genomics Center, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Israela Lerer
- Department of Genetics, Hebrew University-Hadassah Medical Center, Jerusalem, Israel
| | - Judith Dagan
- Department of Genetics, Hebrew University-Hadassah Medical Center, Jerusalem, Israel
| | - Chofit Chai Gadot
- The Genetics Institute and Genomics Center, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Adi Mory
- The Genetics Institute and Genomics Center, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Wilnai
- The Genetics Institute and Genomics Center, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Nino Oniashvili
- Cytogenetic Laboratory, Oncology Department, Schneider Children's Medical Center in Israel, Petah Tikva, Israel
| | - Nir Giladi
- Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Tanya Gurevich
- Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Vardiella Meiner
- Department of Genetics, Hebrew University-Hadassah Medical Center, Jerusalem, Israel
| | - Alexander Lossos
- Department of Neurology, Hebrew University-Hadassah Medical Center, Jerusalem, Israel
| | - Hagit Baris Feldman
- The Genetics Institute and Genomics Center, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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5
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Molecular Characterization of Portuguese Patients with Hereditary Cerebellar Ataxia. Cells 2022; 11:cells11060981. [PMID: 35326432 PMCID: PMC8946949 DOI: 10.3390/cells11060981] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 01/02/2023] Open
Abstract
Hereditary cerebellar ataxia (HCA) comprises a clinical and genetic heterogeneous group of neurodegenerative disorders characterized by incoordination of movement, speech, and unsteady gait. In this study, we performed whole-exome sequencing (WES) in 19 families with HCA and presumed autosomal recessive (AR) inheritance, to identify the causal genes. A phenotypic classification was performed, considering the main clinical syndromes: spastic ataxia, ataxia and neuropathy, ataxia and oculomotor apraxia (AOA), ataxia and dystonia, and ataxia with cognitive impairment. The most frequent causal genes were associated with spastic ataxia (SACS and KIF1C) and with ataxia and neuropathy or AOA (PNKP). We also identified three families with autosomal dominant (AD) forms arising from de novo variants in KIF1A, CACNA1A, or ATP1A3, reinforcing the importance of differential diagnosis (AR vs. AD forms) in families with only one affected member. Moreover, 10 novel causal-variants were identified, and the detrimental effect of two splice-site variants confirmed through functional assays. Finally, by reviewing the molecular mechanisms, we speculated that regulation of cytoskeleton function might be impaired in spastic ataxia, whereas DNA repair is clearly associated with AOA. In conclusion, our study provided a genetic diagnosis for HCA families and proposed common molecular pathways underlying cerebellar neurodegeneration.
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Gentile F, Scarlino S, Falzone YM, Lunetta C, Tremolizzo L, Quattrini A, Riva N. The Peripheral Nervous System in Amyotrophic Lateral Sclerosis: Opportunities for Translational Research. Front Neurosci 2019; 13:601. [PMID: 31293369 PMCID: PMC6603245 DOI: 10.3389/fnins.2019.00601] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/27/2019] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS) has been considered as a disorder of the motor neuron (MN) cell body, recent evidences show the non-cell-autonomous pathogenic nature of the disease. Axonal degeneration, loss of peripheral axons and destruction of nerve terminals are early events in the disease pathogenic cascade, anticipating MN degeneration, and the onset of clinical symptoms. Therefore, although ALS and peripheral axonal neuropathies should be differentiated in clinical practice, they also share damage to common molecular pathways, including axonal transport, RNA metabolism and proteostasis. Thus, an extensive evaluation of the molecular events occurring in the peripheral nervous system (PNS) could be fundamental to understand the pathogenic mechanisms of ALS, favoring the discovery of potential disease biomarkers, and new therapeutic targets.
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Affiliation(s)
- Francesco Gentile
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
| | - Stefania Scarlino
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
| | - Yuri Matteo Falzone
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
- Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Lucio Tremolizzo
- Neurology Unit, ALS Clinic, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy
| | - Angelo Quattrini
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
| | - Nilo Riva
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
- Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
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7
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Elert-Dobkowska E, Stepniak I, Krysa W, Ziora-Jakutowicz K, Rakowicz M, Sobanska A, Pilch J, Antczak-Marach D, Zaremba J, Sulek A. Next-generation sequencing study reveals the broader variant spectrum of hereditary spastic paraplegia and related phenotypes. Neurogenetics 2019; 20:27-38. [PMID: 30778698 PMCID: PMC6411833 DOI: 10.1007/s10048-019-00565-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/11/2019] [Indexed: 12/18/2022]
Abstract
Hereditary spastic paraplegias (HSPs) are clinically and genetically heterogeneous neurodegenerative disorders. Numerous genes linked to HSPs, overlapping phenotypes between HSP subtypes and other neurodegenerative disorders and the HSPs’ dual mode of inheritance (both dominant and recessive) make the genetic diagnosis of HSPs complex and difficult. Out of the original HSP cohort comprising 306 index cases (familial and isolated) who had been tested according to “traditional workflow/guidelines” by Multiplex Ligation-dependent Probe Amplification (MLPA) and Sanger sequencing, 30 unrelated patients (all familial cases) with unsolved genetic diagnoses were tested using next-generation sequencing (NGS). One hundred thirty-two genes associated with spastic paraplegias, hereditary ataxias and related movement disorders were analysed using the Illumina TruSight™ One Sequencing Panel. The targeted NGS data showed pathogenic variants, likely pathogenic variants and those of uncertain significance (VUS) in the following genes: SPAST (spastin, SPG4), ATL1 (atlastin 1, SPG3), WASHC5 (SPG8), KIF5A (SPG10), KIF1A (SPG30), SPG11 (spatacsin), CYP27A1, SETX and ITPR1. Out of the nine genes mentioned above, three have not been directly associated with the HSP phenotype to date. Considering the phenotypic overlap and joint cellular pathways of the HSP, spinocerebellar ataxia (SCA) and amyotrophic lateral sclerosis (ALS) genes, our findings provide further evidence that common genetic testing may improve the diagnostics of movement disorders with a spectrum of ataxia-spasticity signs.
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Affiliation(s)
- Ewelina Elert-Dobkowska
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Iwona Stepniak
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Wioletta Krysa
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Karolina Ziora-Jakutowicz
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland
| | - Maria Rakowicz
- Department of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Anna Sobanska
- Department of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Jacek Pilch
- Department of Paediatric Neurology, Medical University of Silesia, Katowice, Poland
| | - Dorota Antczak-Marach
- Clinic of Neurology of Children and Adolescents, Institute of Mother and Child, Warsaw, Poland
| | - Jacek Zaremba
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland.,Division Five of Medical Sciences, Polish Academy of Science, Warsaw, Poland
| | - Anna Sulek
- Department of Genetics, Institute of Psychiatry and Neurology, Sobieskiego 9 Street, 02-957, Warsaw, Poland.
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Senataxin resolves RNA:DNA hybrids forming at DNA double-strand breaks to prevent translocations. Nat Commun 2018; 9:533. [PMID: 29416069 PMCID: PMC5803260 DOI: 10.1038/s41467-018-02894-w] [Citation(s) in RCA: 221] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 01/05/2018] [Indexed: 12/21/2022] Open
Abstract
Ataxia with oculomotor apraxia 2 (AOA-2) and amyotrophic lateral sclerosis (ALS4) are neurological disorders caused by mutations in the gene encoding for senataxin (SETX), a putative RNA:DNA helicase involved in transcription and in the maintenance of genome integrity. Here, using ChIP followed by high throughput sequencing (ChIP-seq), we report that senataxin is recruited at DNA double-strand breaks (DSBs) when they occur in transcriptionally active loci. Genome-wide mapping unveiled that RNA:DNA hybrids accumulate on DSB-flanking chromatin but display a narrow, DSB-induced, depletion near DNA ends coinciding with senataxin binding. Although neither required for resection nor for timely repair of DSBs, senataxin was found to promote Rad51 recruitment, to minimize illegitimate rejoining of distant DNA ends and to sustain cell viability following DSB production in active genes. Our data suggest that senataxin functions at DSBs in order to limit translocations and ensure cell viability, providing new insights on AOA2/ALS4 neuropathies.
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9
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Groh M, Albulescu LO, Cristini A, Gromak N. Senataxin: Genome Guardian at the Interface of Transcription and Neurodegeneration. J Mol Biol 2016; 429:3181-3195. [PMID: 27771483 DOI: 10.1016/j.jmb.2016.10.021] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/14/2016] [Accepted: 10/15/2016] [Indexed: 12/12/2022]
Abstract
R-loops comprise an RNA/DNA hybrid and a displaced single-stranded DNA. They play crucial biological functions and are implicated in neurological diseases, including ataxias, amyotrophic lateral sclerosis, nucleotide expansion disorders (Friedreich ataxia and fragile X syndrome), and cancer. Currently, it is unclear which mechanisms cause R-loop structures to become pathogenic. The RNA/DNA helicase senataxin (SETX) is one of the best characterised R-loop-binding factors in vivo. Mutations in SETX are linked to two neurodegenerative disorders: ataxia with oculomotor apraxia type 2 (AOA2) and amyotrophic lateral sclerosis type 4 (ALS4). SETX is known to play a role in transcription, neurogenesis, and antiviral response. Here, we review the causes of R-loop dysregulation in neurodegenerative diseases and how these structures contribute to pathomechanisms. We will discuss the importance of SETX as a genome guardian in suppressing aberrant R-loop formation and analyse how SETX mutations can lead to neurodegeneration in AOA2/ALS4. Finally, we will discuss the implications for other R-loop-associated neurodegenerative diseases and point to future therapeutic approaches to treat these disorders.
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Affiliation(s)
- Matthias Groh
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, UK
| | - Laura Oana Albulescu
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, UK
| | - Agnese Cristini
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, UK
| | - Natalia Gromak
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, OX1 3RE, UK.
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Becherel OJ, Sun J, Yeo AJ, Nayler S, Fogel BL, Gao F, Coppola G, Criscuolo C, De Michele G, Wolvetang E, Lavin MF. A new model to study neurodegeneration in ataxia oculomotor apraxia type 2. Hum Mol Genet 2015; 24:5759-74. [PMID: 26231220 PMCID: PMC4581605 DOI: 10.1093/hmg/ddv296] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 06/12/2015] [Accepted: 07/20/2015] [Indexed: 12/18/2022] Open
Abstract
Ataxia oculomotor apraxia type 2 (AOA2) is a rare autosomal recessive cerebellar ataxia. Recent evidence suggests that the protein defective in this syndrome, senataxin (SETX), functions in RNA processing to protect the integrity of the genome. To date, only patient-derived lymphoblastoid cells, fibroblasts and SETX knockdown cells were available to investigate AOA2. Recent disruption of the Setx gene in mice did not lead to neurobehavioral defects or neurodegeneration, making it difficult to study the etiology of AOA2. To develop a more relevant neuronal model to study neurodegeneration in AOA2, we derived neural progenitors from a patient with AOA2 and a control by induced pluripotent stem cell (iPSC) reprogramming of fibroblasts. AOA2 iPSC and neural progenitors exhibit increased levels of oxidative damage, DNA double-strand breaks, increased DNA damage-induced cell death and R-loop accumulation. Genome-wide expression and weighted gene co-expression network analysis in these neural progenitors identified both previously reported and novel affected genes and cellular pathways associated with senataxin dysfunction and the pathophysiology of AOA2, providing further insight into the role of senataxin in regulating gene expression on a genome-wide scale. These data show that iPSCs can be generated from patients with the autosomal recessive ataxia, AOA2, differentiated into neurons, and that both cell types recapitulate the AOA2 cellular phenotype. This represents a novel and appropriate model system to investigate neurodegeneration in this syndrome.
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Affiliation(s)
- Olivier J Becherel
- UQ Centre for Clinical Research (UQCCR), School of Chemistry and Molecular Biosciences and
| | - Jane Sun
- Australian Institute for Bioengineering and Nanotechnology
| | - Abrey J Yeo
- UQ Centre for Clinical Research (UQCCR), School of Medicine, The University of Queensland, Brisbane, QLD 4029, Australia
| | - Sam Nayler
- Australian Institute for Bioengineering and Nanotechnology
| | | | - Fuying Gao
- Department of Psychiatry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA and
| | - Giovanni Coppola
- Department of Neurology and Department of Psychiatry, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA and
| | - Chiara Criscuolo
- Department of Neuroscience and Reproductive and Odontostomatological Sciences, Federico II University, Napoli, Italy
| | - Giuseppe De Michele
- Department of Neuroscience and Reproductive and Odontostomatological Sciences, Federico II University, Napoli, Italy
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11
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Vantaggiato C, Cantoni O, Guidarelli A, Romaniello R, Citterio A, Arrigoni F, Doneda C, Castelli M, Airoldi G, Bresolin N, Borgatti R, Bassi MT. Novel SETX variants in a patient with ataxia, neuropathy, and oculomotor apraxia are associated with normal sensitivity to oxidative DNA damaging agents. Brain Dev 2014; 36:682-9. [PMID: 24183476 DOI: 10.1016/j.braindev.2013.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Homozygous and compound heterozygous mutations in SETX are associated with AOA2 disease, a recessive form of ataxia with oculomotor apraxia and neuropathy with onset of ataxia between the first and second decade of life. The majority of the AOA2 mutated cell lines tested show hypersensitivity to oxidative DNA damaging agents, with one exception. RESULTS We describe a patient presenting with early-onset progressive ataxia, oculomotor apraxia, axonal sensory-motor neuropathy, optic atrophy, delayed psychomotor development, and a behavior disorder. The patient carries two novel missense variants in the SETX gene. Based on the hypothesis that the patient's clinical phenotype may represent an atypical form of the AOA2 disease, we tested the patient-derived cell line for hypersensitivity to oxidative DNA damaging agents, with negative results. CONCLUSIONS The lack of hypersensitivity we observed may be explained either by considering the atypical clinical picture of the patient analyzed or, alternatively, by hypothesizing that the variants detected are not the cause of the observed phenotype. Consistent with the first hypothesis of an atypical AOA2 form and based on the multiple functions of senataxin reported so far, it is likely that different sets of SETX mutations/variants may have variable functional effects that still need to be functionally characterized. The possibility that the severe and complicated clinical picture presented by the patient described here represents a clinical entity differing from the known recessive ataxias should be considered as well.
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Affiliation(s)
- Chiara Vantaggiato
- Scientific Institute IRCCS E. Medea, Laboratory of Molecular Biology, 23842 Bosisio Parini, Lecco, Italy
| | - Orazio Cantoni
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Andrea Guidarelli
- Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
| | - Romina Romaniello
- Scientific Institute IRCCS E. Medea, Neuropsychiatry and Neurorehabilitation Unit, Bosisio Parini, Lecco, Italy
| | - Andrea Citterio
- Scientific Institute IRCCS E. Medea, Laboratory of Molecular Biology, 23842 Bosisio Parini, Lecco, Italy
| | - Filippo Arrigoni
- Scientific Institute IRCCS E.Medea, Neuroimaging Unit, Bosisio Parini, Lecco, Italy
| | - Chiara Doneda
- Radiology and Pediatric Neuroradiology, Buzzi Hospital, Milan, Italy
| | - Marianna Castelli
- Scientific Institute IRCCS E. Medea, Laboratory of Molecular Biology, 23842 Bosisio Parini, Lecco, Italy
| | - Giovanni Airoldi
- Scientific Institute IRCCS E. Medea, Laboratory of Molecular Biology, 23842 Bosisio Parini, Lecco, Italy
| | - Nereo Bresolin
- Scientific Institute IRCCS E. Medea, Laboratory of Molecular Biology, 23842 Bosisio Parini, Lecco, Italy; Dino Ferrari Centre, IRCCS Ca' Granda, Ospedale Maggiore Policlinico Foundation, Department of Physiopathology and Transplantation, University of Milan, Italy
| | - Renato Borgatti
- Scientific Institute IRCCS E. Medea, Neuropsychiatry and Neurorehabilitation Unit, Bosisio Parini, Lecco, Italy
| | - Maria Teresa Bassi
- Scientific Institute IRCCS E. Medea, Laboratory of Molecular Biology, 23842 Bosisio Parini, Lecco, Italy.
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Roda RH, Rinaldi C, Singh R, Schindler AB, Blackstone C. Ataxia with oculomotor apraxia type 2 fibroblasts exhibit increased susceptibility to oxidative DNA damage. J Clin Neurosci 2014; 21:1627-31. [PMID: 24814856 DOI: 10.1016/j.jocn.2013.11.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/05/2013] [Accepted: 11/10/2013] [Indexed: 10/25/2022]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is an autosomal recessive cerebellar ataxia associated with mutations in SETX, which encodes the senataxin protein, a DNA/RNA helicase. We describe the clinical phenotype and molecular characterization of a Colombian AOA2 patient who is compound heterozygous for a c.994 C>T (p.R332W) missense mutation in exon 7 and a c.6848_6851delCAGA (p.T2283KfsX32) frameshift deletion in SETX exon 21. Immunocytochemistry of patient-derived fibroblasts revealed a normal cellular distribution of the senataxin protein, suggesting that these mutations do not lead to loss or mis-localization of the protein, but rather that aberrant function of senataxin underlies the disease pathogenesis. Furthermore, we used the alkaline comet assay to demonstrate that patient-derived fibroblast cells exhibit an increased susceptibility to oxidative DNA damage. This assay provides a novel and additional means to establish pathogenicity of SETX mutations.
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Affiliation(s)
- Ricardo H Roda
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C-911, 9000 Rockville Pike, Bethesda, MD 20892-3738, USA.
| | - Carlo Rinaldi
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Rajat Singh
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C-911, 9000 Rockville Pike, Bethesda, MD 20892-3738, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Alice B Schindler
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C-911, 9000 Rockville Pike, Bethesda, MD 20892-3738, USA
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13
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Richard P, Manley JL. SETX sumoylation: A link between DNA damage and RNA surveillance disrupted in AOA2. Rare Dis 2014; 2:e27744. [PMID: 25054092 PMCID: PMC4091563 DOI: 10.4161/rdis.27744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 12/18/2013] [Accepted: 01/06/2014] [Indexed: 01/09/2023] Open
Abstract
Senataxin (SETX) is a putative RNA:DNA helicase that is mutated in two distinct juvenile neurological disorders, AOA2 and ALS4. SETX is involved in the response to oxidative stress and is suggested to resolve R loops formed at transcription termination sites or at sites of collisions between the transcription and replication machineries. R loops are hybrids between RNA and DNA that are believed to lead to DNA damage and genomic instability. We discovered that Rrp45, a core component of the exosome, is a SETX-interacting protein and that the interaction depends on modification of SETX by sumoylation. Importantly, we showed that AOA2 but not ALS4 mutations prevented both SETX sumoylation and the Rrp45 interaction. We also found that upon replication stress induction, SETX and Rrp45 co-localize in nuclear foci that constitute sites of R-loop formation generated by transcription and replication machinery collisions. We suggest that SETX links transcription, DNA damage and RNA surveillance, and discuss here how this link can be relevant to AOA2 disease.
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Affiliation(s)
- Patricia Richard
- Department of Biological Sciences; Columbia University; New York, NY USA
| | - James L Manley
- Department of Biological Sciences; Columbia University; New York, NY USA
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Abstract
OBJECTIVE In this paper, we document two cases of a new SETX mutation (820:A>G) combined with an established recessive SETX mutation (5927:T>G) causing ataxia with oculomotor apraxia type 2 (AOA2). METHODS The patients had a detailed neurological history and examination performed. Radiological imaging was obtained and genetic analysis was obtained. RESULTS Both siblings demonstrated healthy and normal growth until adolescence. At that time, slowed speech, hypophonia, dysarthria, extraocular muscle dysfunction and some mild choreiform movements began to appear. Family history included some movement disorder difficulties in second degree relatives. The diagnosis of AOA2 was confirmed by genetic testing. CONCLUSIONS We describe a new SETX gene mutation, which when combined with a recognized SETX mutation results in AOA2. The clinical, radiographic and ancillary testing are described.
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Affiliation(s)
- Neil Datta
- Boston University School of Medicine, Department of Neurology, Boston, MA, USA.
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Clinical and molecular findings of ataxia with oculomotor apraxia type 2 (AOA2) in 5 Tunisian families. ACTA ACUST UNITED AC 2013; 21:241-5. [PMID: 23111195 DOI: 10.1097/pdm.0b013e318257ad9a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is a recently described autosomal recessive cerebellar ataxia caused by mutations in the SETX gene. It is a rare monogenic disease characterized by progressive cerebellar ataxia, oculomotor apraxia, axonal sensorimotor neuropathy, and an elevated serum α-fetoprotein level. To date, >100 AOA2 patients have been described and 75 different mutations in the SETX gene have been identified. We report here the clinical and genetic findings of 13 AOA2 patients from 5 unrelated Tunisian consanguineous families. DNA was collected from probands and available family members, and the 24 SETX exons were screened by direct sequencing. Four different homozygous SETX gene mutations were identified. The missense mutation 915G>T [W305C] has been described previously in Algeria. The 3 other SETX mutations are novel, including a missense mutation c.7231C>T [R 2380 W], a nonsense mutation c.6475 C>T [R2098X], and a deletion c.7180-7183delAAAA [D2332fsX2343]. More extensive screening by molecular genetic analysis of SETX in patients with Friedreich ataxia-like phenotype may show that AOA2 is more common in Tunisia than previously thought.
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Reynolds JJ, Stewart GS. A single strand that links multiple neuropathologies in human disease. ACTA ACUST UNITED AC 2013; 136:14-27. [PMID: 23365091 DOI: 10.1093/brain/aws310] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The development of the human central nervous system is a complex process involving highly coordinated periods of neuronal proliferation, migration and differentiation. Disruptions in these neurodevelopmental processes can result in microcephaly, a neuropathological disorder characterized by a reduction in skull circumference and total brain volume, whereas a failure to maintain neuronal health in the adult brain can lead to progressive neurodegeneration. Defects in the cellular pathways that detect and repair DNA damage are a common cause of both these neuropathologies and are associated with a growing number of hereditary human disorders. In particular, defects in the repair of DNA single strand breaks, one of the most commonly occurring types of DNA lesion, have been associated with three neuropathological diseases: ataxia oculomotor apraxia 1, spinocerebellar ataxia with neuronal neuropathy 1 and microcephaly, early-onset, intractable seizures and developmental delay. A striking similarity between these three human diseases is that they are all caused by mutations in DNA end processing factors, suggesting that a particularly crucial stage of DNA single strand break repair is the repair of breaks with 'damaged' termini. Additionally all three disorders lack any extraneurological symptoms, such as immunodeficiency and cancer predisposition, which are typically found in other human diseases associated with defective DNA repair. However despite these similarities, two of these disorders present with progressive cerebellar degeneration, whereas the third presents with severe microcephaly. This review discusses the molecular defects behind these disorders and presents several hypotheses based on current literature on a number of important questions, in particular, how do mutations in different end processing factors within the same DNA repair pathway lead to such different neuropathologies?
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Affiliation(s)
- John J Reynolds
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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Cozzolino M, Pesaresi MG, Gerbino V, Grosskreutz J, Carrì MT. Amyotrophic lateral sclerosis: new insights into underlying molecular mechanisms and opportunities for therapeutic intervention. Antioxid Redox Signal 2012; 17:1277-330. [PMID: 22413952 DOI: 10.1089/ars.2011.4328] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent years have witnessed a renewed interest in the pathogenic mechanisms of amyotrophic lateral sclerosis (ALS), a late-onset progressive degeneration of motor neurons. The discovery of new genes associated with the familial form of the disease, along with a deeper insight into pathways already described for this disease, has led scientists to reconsider previous postulates. While protein misfolding, mitochondrial dysfunction, oxidative damage, defective axonal transport, and excitotoxicity have not been dismissed, they need to be re-examined as contributors to the onset or progression of ALS in the light of the current knowledge that the mutations of proteins involved in RNA processing, apparently unrelated to the previous "old partners," are causative of the same phenotype. Thus, newly envisaged models and tools may offer unforeseen clues on the etiology of this disease and hopefully provide the key to treatment.
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Vantaggiato C, Bondioni S, Airoldi G, Bozzato A, Borsani G, Rugarli EI, Bresolin N, Clementi E, Bassi MT. Senataxin modulates neurite growth through fibroblast growth factor 8 signalling. ACTA ACUST UNITED AC 2011; 134:1808-28. [PMID: 21576111 DOI: 10.1093/brain/awr084] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Senataxin is encoded by the SETX gene and is mainly involved in two different neurodegenerative diseases, the dominant juvenile form of amyotrophic lateral sclerosis type 4 and a recessive form of ataxia with oculomotor apraxia type 2. Based on protein homology, senataxin is predicted to be a putative DNA/RNA helicase, while senataxin interactors from patients' lymphoblast cell lines suggest a possible involvement of the protein in different aspects of RNA metabolism. Except for an increased sensitivity to oxidative DNA damaging agents shown by some ataxia with neuropathy patients' cell lines, no data are available about possible functional consequences of dominant SETX mutations and no studies address the function of senataxin in neurons. To start elucidating the physiological role of senataxin in neurons and how disease-causing mutations in this protein lead to neurodegeneration, we analysed the effect of senataxin on neuronal differentiation in primary hippocampal neurons and retinoic acid-treated P19 cells by modulating the expression levels of wild-type senataxin and three different dominant mutant forms of the protein. Wild-type senataxin overexpression was required and sufficient to trigger neuritogenesis and protect cells from apoptosis during differentiation. These actions were reversed by silencing of senataxin. In contrast, overexpression of the dominant mutant forms did not affect the regular differentiation process in primary hippocampal neurons. Analysis of the cellular pathways leading to neuritogenesis and cytoprotection revealed a role of senataxin in modulating the expression levels and signalling activity of fibroblast growth factor 8. Silencing of senataxin reduced, while overexpression enhanced, fibroblast growth factor 8 expression levels and the phosphorylation of related target kinases and effector proteins. The effects of senataxin overexpression were prevented when fibroblast growth factor 8 signalling was inhibited, while exogenous fibroblast growth factor 8 reversed the effects of senataxin silencing. Overall, these results reveal a key role of senataxin in neuronal differentiation through the fibroblast growth factor 8 signalling and provide initial molecular bases to explain the neurodegeneration associated with loss-of-function mutations in senataxin found in recessive ataxia. The lack of effect on neuritogenesis observed with the overexpression of the dominant mutant forms of senataxin apparently excludes a dominant negative effect of these mutants while favouring haploinsufficiency as the pathogenic mechanism implicated in the amyotrophic lateral sclerosis 4-related degenerative condition. Alternatively, a different protein function, other than the one involved in neuritogenesis, may be implicated in these dominant degenerative processes.
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Affiliation(s)
- Chiara Vantaggiato
- E. Medea Scientific Institute, Laboratory of Molecular Biology, Via D. L. Monza 20, 23842 Bosisio Parini, Lecco, Italy
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De Amicis A, Piane M, Ferrari F, Fanciulli M, Delia D, Chessa L. Role of senataxin in DNA damage and telomeric stability. DNA Repair (Amst) 2010; 10:199-209. [PMID: 21112256 DOI: 10.1016/j.dnarep.2010.10.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 09/28/2010] [Accepted: 10/30/2010] [Indexed: 11/15/2022]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is an autosomal recessive neurodegenerative disorder characterized by cerebellar ataxia and oculomotor apraxia. The gene mutated in AOA2, SETX, encodes senataxin (SETX), a putative DNA/RNA helicase. The presence of the helicase domain led us to investigate whether SETX might play a role in DNA damage repair and telomere stability. We analyzed the response of AOA2 lymphocytes and lymphoblasts after treatment with camptothecin (CPT), mitomycin C (MMC), H₂O₂ and X-rays by cytogenetic and Q-FISH (quantitative-FISH) assays. The rate of chromosomal aberrations was normal in AOA2 cells after treatment with CPT, MMC, H₂O₂ and X-rays. Conversely, Q-FISH analysis showed constitutively reduced telomere length in AOA2 lymphocytes, compared to age-matched controls. Furthermore, CPT- or X-ray-induced telomere shortening was more marked in AOA2 than in control cells. The partial co-localization of SETX with telomeric DNA, demonstrated by combined immunofluorescence-Q-FISH and chromatin immunoprecipitation, suggests a possible involvement of SETX in telomere stability.
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Affiliation(s)
- Andrea De Amicis
- II School of Medicine, Department of Clinical and Molecular Medicine, University La Sapienza, Roma, Italy. andrea.deamicis@unirom
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Iltis I, Hutter D, Bushara KO, Clark HB, Gross M, Eberly LE, Gomez CM, Oz G. (1)H MR spectroscopy in Friedreich's ataxia and ataxia with oculomotor apraxia type 2. Brain Res 2010; 1358:200-10. [PMID: 20713024 DOI: 10.1016/j.brainres.2010.08.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Revised: 08/07/2010] [Accepted: 08/09/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND AIM Friedreich's ataxia (FRDA) and ataxia with oculomotor apraxia type 2 (AOA2) are the two most frequent forms of autosomal recessive cerebellar ataxias. However, brain metabolism in these disorders is poorly characterized and biomarkers of the disease progression are lacking. We aimed at assessing the neurochemical profile of the pons, the cerebellar hemisphere and the vermis in patients with FRDA and AOA2 to identify potential biomarkers of these diseases. METHODS Short-echo, single-voxel proton ((1)H) magnetic resonance spectroscopy data were acquired from 8 volunteers with FRDA, 9 volunteers with AOA2, and 38 control volunteers at 4T. Disease severity was assessed by the Friedreich's Ataxia Rating Scale (FARS). RESULTS Neuronal loss/dysfunction was indicated in the cerebellar vermis and hemispheres in both diseases by lower total N-acetylaspartate levels than controls. The putative gliosis marker myo-inositol was higher than controls in the vermis and pons in AOA2 and in the vermis in FRDA. Total creatine, another potential gliosis marker, was higher in the cerebellar hemispheres in FRDA relative to controls. Higher glutamine in FRDA and lower glutamate in AOA2 than controls were observed in the vermis, indicating different mechanisms possibly leading to altered glutamatergic neurotransmission. In AOA2, total N-acetylaspartate levels in the cerebellum strongly correlated with the FARS score (p<0.01). CONCLUSION Distinct neurochemical patterns were observed in the two patient populations, warranting further studies with larger patient populations to determine if the alterations in metabolite levels observed here may be utilized to monitor disease progression and treatment.
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Affiliation(s)
- Isabelle Iltis
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA.
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